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Sample records for reducing microbial populations

  1. Evaluation of chemical immersion treatments to reduce microbial populations in fresh beef.

    Science.gov (United States)

    Kassem, Ahmed; Meade, Joseph; Gibbons, James; McGill, Kevina; Walsh, Ciara; Lyng, James; Whyte, Paul

    2017-11-16

    The aim of the current study was to assess the ability of a number of chemicals (acetic Acid (AA), citric acid (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes) on raw beef using an immersion system. The following concentrations of each chemical were used: 3 & 5% for AA, CA, LA, SD and 10 &12% for TSP. Possible synergistic effects of using combinations of two chemicals sequentially (LA+CA and LA+AA) were also investigated. L*, a* and b* values were measured before and after treatments and ΔE* values were calculated in order to determine any changes in the color of meat due to the use of these chemicals. In general, all chemical treatments resulted in significantly (p0.05). The application of combinations of chemical immersion treatments (LA3%+AA3% and LA3%+CA3%) did not result in further significant reductions in microbial populations when compared to single chemical treatments (P3 immediately after treatment and after 24h storage. The remaining treatments did not result in significant changes to the color of raw beef. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. The Abundance and Activity of Nitrate-Reducing Microbial Populations in Estuarine Sediments

    Science.gov (United States)

    Cardarelli, E.; Francis, C. A.

    2014-12-01

    Estuaries are productive ecosystems that ameliorate nutrient and metal contaminants from surficial water supplies. At the intersection of terrestrial and aquatic environments, estuarine sediments host major microbially-mediated geochemical transformations. These include denitrification (the conversion of nitrate to nitrous oxide and/or dinitrogen) and dissimilatory nitrate reduction to ammonium (DNRA). Denitrification has historically been seen as the predominant nitrate attenuation process and functions as an effective sink for nitrate. DNRA has previously been believed to be a minor nitrate reduction process and transforms nitrate within the ecosystem to ammonium, a more biologically available N species. Recent studies have compared the two processes in coastal environments and determined fluctuating environmental conditions may suppress denitrification, supporting an increased role for DNRA in the N cycle. Nitrate availability and salinity are factors thought to influence the membership of the microbial communities present, and the nitrate reduction process that predominates. The aim of this study is to investigate how nitrate concentration and salinity alter the transcript abundances of N cycling functional gene markers for denitrification (nirK, nirS) and DNRA (nrfA) in estuarine sediments at the mouth of the hypernutrified Old Salinas River, CA. Short-term whole core incubations amended with artificial freshwater/artificial seawater (2 psu, 35 psu) and with varying NO3- concentrations (200mM, 2000mM) were conducted to assess the activity as well as the abundance of the nitrate-reducing microbial populations present. Gene expression of nirK, nirS, and nrfA at the conclusion of the incubations was quantified using reverse transcription quantitative polymerase chain reaction (RT-qPCR). High abundances of nirK, nirS, and nrfA under particular conditions coupled with the resulting geochemical data ultimately provides insight onto how the aforementioned factors

  3. On the use of antibiotics to reduce rhizoplane microbial populations in root physiology and ecology investigations

    Science.gov (United States)

    Smart, D. R.; Ferro, A.; Ritchie, K.; Bugbee, B. G.

    1995-01-01

    No straightforward method exists for separating the proportion of ion exchange and respiration due to rhizoplane microbial organisms from that of root ion exchange and respiration. We examined several antibiotics that might be used for the temporary elimination of rhizoplane bacteria from hydroponically grown wheat roots (Triticum aestivum cv. Veery 10). Each antibiotic was tested for herbicidal activity and plate counts were used to enumerate bacteria and evaluate antibiotic kinetics. Only lactam antibiotics (penicillins and cephalosporins) did not reduce wheat growth rates. Aminoglycosides, the pyrimidine trimethoprim, colistin and rifampicin reduced growth rates substantially. Antibiotics acted slowly, with maximum reductions in rhizoplane bacteria occurring after more than 48 h of exposure. Combinations of nonphytotoxic antibiotics reduced platable rhizoplane bacteria by as much as 98%; however, this was generally a reduction from about 10(9) to 10(6) colony forming units per gram of dry root mass, so that many viable bacteria remained on root surfaces. We present evidence which suggests that insufficient bacterial biomass exists on root surfaces of nonstressed plants grown under well-aerated conditions to quantitatively interfere with root nitrogen absorption measurements.

  4. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations.

    Science.gov (United States)

    Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E; Geelhoed, Jeanine S; Strous, Marc; Ruff, S Emil

    2017-12-01

    For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ' U Sabulitectum silens' and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate‐reducing benthic microbial populations

    Science.gov (United States)

    Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E.; Geelhoed, Jeanine S.; Strous, Marc

    2017-01-01

    Summary For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate‐reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate‐ and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24‐12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate‐reducing microbial communities and their adaptation to a dynamic environment. PMID:28836729

  6. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations

    NARCIS (Netherlands)

    Saad, S.; Bhatnagar, S.; Tegetmeyer, H.E.; Geelhoed, J.S.; Strous, M.; Ruff, S.E.

    2017-01-01

    SummaryFor the anaerobic remineralization of organic matter inmarine sediments, sulfate reduction coupled to fer-mentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidalsediments under defined conditions in continuousculture. We transiently exposed

  7. Microbial populations in contaminant plumes

    Science.gov (United States)

    Haack, Sheridan K.; Bekins, Barbara A.

    Efficient biodegradation of subsurface contaminants requires two elements: (1) microbial populations with the necessary degradative capabilities, and (2) favorable subsurface geochemical and hydrological conditions. Practical constraints on experimental design and interpretation in both the hydrogeological and microbiological sciences have resulted in limited knowledge of the interaction between hydrogeological and microbiological features of subsurface environments. These practical constraints include: (1) inconsistencies between the scales of investigation in the hydrogeological and microbiological sciences, and (2) practical limitations on the ability to accurately define microbial populations in environmental samples. However, advances in application of small-scale sampling methods and interdisciplinary approaches to site investigations are beginning to significantly improve understanding of hydrogeological and microbiological interactions. Likewise, culture-based and molecular analyses of microbial populations in subsurface contaminant plumes have revealed significant adaptation of microbial populations to plume environmental conditions. Results of recent studies suggest that variability in subsurface geochemical and hydrological conditions significantly influences subsurface microbial-community structure. Combined investigations of site conditions and microbial-community structure provide the knowledge needed to understand interactions between subsurface microbial populations, plume geochemistry, and contaminant biodegradation. La biodégradation efficace des polluants souterrains requiert deux éléments: des populations microbiennes possédant les aptitudes nécessaires à la dégradation, et des conditions géochimiques et hydrologiques souterraines favorables. Des contraintes pratiques sur la conception et l'interprétation des expériences à la fois en microbiologie et en hydrogéologie ont conduit à une connaissance limitée des interactions entre les

  8. Interval scanning photomicrography of microbial cell populations.

    Science.gov (United States)

    Casida, L. E., Jr.

    1972-01-01

    A single reproducible area of the preparation in a fixed focal plane is photographically scanned at intervals during incubation. The procedure can be used for evaluating the aerobic or anaerobic growth of many microbial cells simultaneously within a population. In addition, the microscope is not restricted to the viewing of any one microculture preparation, since the slide cultures are incubated separately from the microscope.

  9. Microbial population changes in tropical agricultural soil ...

    African Journals Online (AJOL)

    Impacts of crude petroleum pollution on the soil environment and microbial population dynamics as well as recovery rates of an abandoned farmland was monitored for seven months spanning the two major seasons in Nigeria with a ... The physico-chemistry of the control and contaminated soils differed just significantly (P ...

  10. Septic tank additive impacts on microbial populations.

    Science.gov (United States)

    Pradhan, S; Hoover, M T; Clark, G H; Gumpertz, M; Wollum, A G; Cobb, C; Strock, J

    2008-01-01

    Environmental health specialists, other onsite wastewater professionals, scientists, and homeowners have questioned the effectiveness of septic tank additives. This paper describes an independent, third-party, field scale, research study of the effects of three liquid bacterial septic tank additives and a control (no additive) on septic tank microbial populations. Microbial populations were measured quarterly in a field study for 12 months in 48 full-size, functioning septic tanks. Bacterial populations in the 48 septic tanks were statistically analyzed with a mixed linear model. Additive effects were assessed for three septic tank maintenance levels (low, intermediate, and high). Dunnett's t-test for tank bacteria (alpha = .05) indicated that none of the treatments were significantly different, overall, from the control at the statistical level tested. In addition, the additives had no significant effects on septic tank bacterial populations at any of the septic tank maintenance levels. Additional controlled, field-based research iswarranted, however, to address additional additives and experimental conditions.

  11. Metabolic heterogeneity in clonal microbial populations.

    Science.gov (United States)

    Takhaveev, Vakil; Heinemann, Matthias

    2018-02-21

    In the past decades, numerous instances of phenotypic diversity were observed in clonal microbial populations, particularly, on the gene expression level. Much less is, however, known about phenotypic differences that occur on the level of metabolism. This is likely explained by the fact that experimental tools probing metabolism of single cells are still at an early stage of development. Here, we review recent exciting discoveries that point out different causes for metabolic heterogeneity within clonal microbial populations. These causes range from ecological factors and cell-inherent dynamics in constant environments to molecular noise in gene expression that propagates into metabolism. Furthermore, we provide an overview of current methods to quantify the levels of metabolites and biomass components in single cells. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Effect of Gamma radiation on microbial population of natural casings

    International Nuclear Information System (INIS)

    Trigo, M.J.; Fraqueza, M.J.

    1998-01-01

    The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganims, agents of foodborn diseases. The aim of this work is to evaluate the killing effect of gamma radiation on the resident microbial population of pork and beef casings, to improve their hygiene and safety. Portions of fresh pork (small intestine and colon) and dry beef casings were irradiated in a Cobalt 60 source with absorbed doses of 1, 2, 5 and 10 kGy. The D 10 values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D 10 value found in beef dry casings (small intestine) was 10.17 kGy. Radurization with 5 kGy was able to reduce, at least, 6 logs the coliform bacteria in pork casings. The killing effect over faecal Streptococci was 4 logs for pork fresh casings and 2 logs for beef dry casings. Gamma radiation with 5 kGy proved to be a convenient method to reduce substantially the microbial population of pork fresh casings. Otherwise, the microbial population of beef dry casings still resisted to 10 kGy

  13. The effects of boron management on soil microbial population and ...

    African Journals Online (AJOL)

    Soil microorganisms directly influence boron content of soil as maximum boron release corresponds with the highest microbial activity. The objective of this study is to determine the effects of different levels of boron fertilizer on microbial population, microbial respiration and soil enzyme activities in different soil depths in ...

  14. Effects of nitrate addition to a diet on fermentation and microbial populations in the rumen of goats, with special reference to Selenomonas ruminantium having the ability to reduce nitrate and nitrite.

    Science.gov (United States)

    Asanuma, Narito; Yokoyama, Shota; Hino, Tsuneo

    2015-04-01

    This study investigated the effects of dietary nitrate addition on ruminal fermentation characteristics and microbial populations in goats. The involvement of Selenomonas ruminantium in nitrate and nitrite reduction in the rumen was also examined. As the result of nitrate feeding, the total concentration of ruminal volatile fatty acids decreased, whereas the acetate : propionate ratio and the concentrations of ammonia and lactate increased. Populations of methanogens, protozoa and fungi, as estimated by real-time PCR, were greatly decreased as a result of nitrate inclusion in the diet. There was modest or little impact of nitrate on the populations of prevailing species or genus of bacteria in the rumen, whereas Streptococcus bovis and S. ruminantium significantly increased. Both the activities of nitrate reductase (NaR) and nitrite reductase (NiR) per total mass of ruminal bacteria were increased by nitrate feeding. Quantification of the genes encoding NaR and NiR by real-time PCR with primers specific for S. ruminantium showed that these genes were increased by feeding nitrate, suggesting that the growth of nitrate- and nitrite-reducing S. ruminantium is stimulated by nitrate addition. Thus, S. ruminantium is likely to play a major role in nitrate and nitrite reduction in the rumen. © 2014 Japanese Society of Animal Science.

  15. Microbial Character Related Sulfur Cycle under Dynamic Environmental Factors Based on the Microbial Population Analysis in Sewerage System.

    Science.gov (United States)

    Dong, Qian; Shi, Hanchang; Liu, Yanchen

    2017-01-01

    The undesired sulfur cycle derived by microbial population can ultimately causes the serious problems of sewerage systems. However, the microbial community characters under dynamic environment factors in actual sewerage system is still not enough. This current study aimed to character the distributions and compositions of microbial communities that participate in the sulfur cycle under the dynamic environmental conditions in a local sewerage system. To accomplish this, microbial community compositions were assessed using 454 high-throughput sequencing (16S rDNA) combined with dsrB gene-based denaturing gradient gel electrophoresis. The results indicated that a higher diversity of microbial species was present at locations in sewers with high concentrations of H 2 S. Actinobacteria and Proteobacteria were dominant in the sewerage system, while Actinobacteria alone were dominant in regions with high concentrations of H 2 S. Specifically, the unique operational taxonomic units could aid to characterize the distinct microbial communities within a sewerage manhole. The proportion of sulfate-reducing bacteria, each sulfur-oxidizing bacteria (SOB) were strongly correlated with the liquid parameters (DO, ORP, COD, Sulfide, NH 3 -N), while the Mycobacterium and Acidophilic SOB (M&A) was strongly correlated with gaseous factors within the sewer, such as H 2 S, CH 4 , and CO. Identifying the distributions and proportions of critical microbial communities within sewerage systems could provide insights into how the microbial sulfur cycle is affected by the dynamic environmental conditions that exist in sewers and might be useful for explaining the potential sewerage problems.

  16. Microbial population changes in tropical agricultural soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... Microbial degradation is known to be an efficient process in the in ..... exhibited a great impact on the ecology of the soil by causing drastic ... city of the soil (Dibble and Bartha, 1979). Hydrocarbon .... Atlas RM (1991). Microbial ...

  17. Biotic interactions reduce microbial carbon use efficiency

    Science.gov (United States)

    Bradford, M.; Maynard, D. S.

    2017-12-01

    The efficiency by which microbes decompose organic matter governs the amount of carbon that is retained in microbial biomass versus lost to the atmosphere as respiration. This carbon use efficiency (CUE) is affected by various abiotic conditions, such as temperature and nutrient availability. In biogeochemical model simulations, CUE is a key variable regulating how much soil carbon is stored or lost from ecosystems under simulated global changes, such as climate warming. Theoretically, the physiological costs of biotic interactions such as competition should likewise alter CUE, yet the direction and magnitude of these costs are untested. Here we conduct a microcosm experiment to quantify how competitive interactions among saprotrophic fungi alter growth, respiration, and CUE. Free-living decomposer fungi representing a broad range of traits and phylogenies were grown alone, in pairwise competition, and in multi-species (up to 15) communities. By combing culturing and stable carbon isotope approaches, we could resolve the amount of carbon substrate allocated to fungal biomass versus respiration, and so estimate CUE. By then comparing individual performance to community-level outcomes, we show that species interactions induce consistent declines in CUE, regardless of abiotic conditions. Pairwise competition lowers CUE by as much as 25%, with the magnitude of these costs equal to or greater than the observed variation across abiotic conditions. However, depending on the competitive network structure, increasing species richness led to consistent gains or declines in CUE. Our results suggest that the extent to which microbial-mediated carbon fluxes respond to environmental change may be influenced strongly by competitive interactions. As such, knowledge of abiotic conditions and community composition is necessary to confidently project CUE and hence ecosystem carbon dynamics.

  18. Prescreening of microbial populations for the assessment of sequencing potential.

    Science.gov (United States)

    Hanning, Irene B; Ricke, Steven C

    2011-01-01

    Next-generation sequencing (NGS) is a powerful tool that can be utilized to profile and compare microbial populations. By amplifying a target gene present in all bacteria and subsequently sequencing amplicons, the bacteria genera present in the populations can be identified and compared. In some scenarios, little to no difference may exist among microbial populations being compared in which case a prescreening method would be practical to determine which microbial populations would be suitable for further analysis by NGS. Denaturing density-gradient electrophoresis (DGGE) is relatively cheaper than NGS and the data comparing microbial populations are ready to be viewed immediately after electrophoresis. DGGE follows essentially the same initial methodology as NGS by targeting and amplifying the 16S rRNA gene. However, as opposed to sequencing amplicons, DGGE amplicons are analyzed by electrophoresis. By prescreening microbial populations with DGGE, more efficient use of NGS methods can be accomplished. In this chapter, we outline the protocol for DGGE targeting the same gene (16S rRNA) that would be targeted for NGS to compare and determine differences in microbial populations from a wide range of ecosystems.

  19. Experimental demonstration of an Allee effect in microbial populations

    OpenAIRE

    Kaul, RajReni B.; Kramer, Andrew M.; Dobbs, Fred C.; Drake, John M.

    2016-01-01

    Microbial populations can be dispersal limited. However, microorganisms that successfully disperse into physiologically ideal environments are not guaranteed to establish. This observation contradicts the Baas-Becking tenet: ?Everything is everywhere, but the environment selects?. Allee effects, which manifest in the relationship between initial population density and probability of establishment, could explain this observation. Here, we experimentally demonstrate that small populations of Vi...

  20. Microbially-reduced graphene scaffolds to facilitate extracellular electron transfer in microbial fuel cells.

    Science.gov (United States)

    Yuan, Yong; Zhou, Shungui; Zhao, Bo; Zhuang, Li; Wang, Yueqiang

    2012-07-01

    A one-pot method is exploited by adding graphene oxide (GO) and acetate into an microbial fuel cell (MFC) in which GO is microbially reduced, leading to in situ construction of a bacteria/graphene network in the anode. The obtained microbially reduced graphene (MRG) exhibits comparable conductivity and physical characteristics to the chemically reduced graphene. Electrochemical measurements reveal that the number of exoelectrogens involved in extracellular electron transfer (EET) to the solid electrode, increases due to the presence of graphene scaffolds, and the EET is facilitated in terms of electron transfer kinetics. As a result, the maximum power density of the MFC is enhanced by 32% (from 1440 to 1905 mW m(-2)) and the coulombic efficiency is improved by 80% (from 30 to 54%). The results demonstrate that the construction of the bacteria/graphene network is an effective alternative to improve the MFC performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Exogenous Nitrogen Addition Reduced the Temperature Sensitivity of Microbial Respiration without Altering the Microbial Community Composition

    Directory of Open Access Journals (Sweden)

    Hui Wei

    2017-12-01

    Full Text Available Atmospheric nitrogen (N deposition is changing in both load quantity and chemical composition. The load effects have been studied extensively, whereas the composition effects remain poorly understood. We conducted a microcosm experiment to study how N chemistry affected the soil microbial community composition characterized by phospholipid fatty acids (PLFAs and activity indicated by microbial CO2 release. Surface and subsurface soils collected from an old-growth subtropical forest were supplemented with three N-containing materials (ammonium, nitrate, and urea at the current regional deposition load (50 kg ha-1 yr-1 and incubated at three temperatures (10, 20, and 30°C to detect the interactive effects of N deposition and temperature. The results showed that the additions of N, regardless of form, did not alter the microbial PLFAs at any of the three temperatures. However, the addition of urea significantly stimulated soil CO2 release in the early incubation stage. Compared with the control, N addition consistently reduced the temperature dependency of microbial respiration, implying that N deposition could potentially weaken the positive feedback of the warming-stimulated soil CO2 release to the atmosphere. The consistent N effects for the surface and subsurface soils suggest that the effects of N on soil microbial communities may be independent of soil chemical contents and stoichiometry.

  2. ECONOMIC RETURNS FROM REDUCING POULTRY LITTER PHOSPHORUS WITH MICROBIAL PHYTASE

    OpenAIRE

    Bosch, Darrell J.; Zhu, Minkang; Kornegay, Ervin T.

    1997-01-01

    Requiring that crop applications of manure be based on phosphorus content (P-standard) could increase poultry litter disposal costs. Microbial phytase reduces litter P content and could reduce litter disposal costs under a P-standard. For a representative Virginia turkey farm, phytase costs $2,500 and could increase value of litter used for fertilizer on the turkey farm by $390 and reduce supplemental P feed costs by $1,431. Based on assumed litter demand and supply, estimated litter export p...

  3. Cooperation, cheating, and collapse in microbial populations

    Science.gov (United States)

    Gore, Jeff

    2012-02-01

    Natural populations can suffer catastrophic collapse in response to small changes in environmental conditions, and recovery after such a collapse can be exceedingly difficult. We have used laboratory yeast populations to study proposed early warning signals of impending extinction. Yeast cooperatively breakdown the sugar sucrose, meaning that there is a minimum number of cells required to sustain the population. We have demonstrated experimentally that the fluctuations in the population size increase in magnitude and become slower as the population approaches collapse. The cooperative nature of yeast growth on sucrose suggests that the population may be susceptible to cheater cells, which do not contribute to the public good and instead merely take advantage of the cooperative cells. We have confirmed this possibility experimentally by using a cheater yeast strain that lacks the gene encoding the cooperative behavior [1]. However, recent results in the lab demonstrate that the presence of a bacterial competitor may drive cooperation within the yeast population.[4pt] [1] Gore et al, Nature 459, 253 -- 256 (2009)

  4. Feedback between Population and Evolutionary Dynamics Determines the Fate of Social Microbial Populations

    Science.gov (United States)

    Sanchez, Alvaro; Gore, Jeff

    2013-01-01

    The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50–100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators “spiral” to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the demographic fate

  5. feedback between population and evolutionary dynamics determines the fate of social microbial populations.

    Directory of Open Access Journals (Sweden)

    Alvaro Sanchez

    Full Text Available The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50-100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators "spiral" to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the

  6. 2007 Microbial Population Biology (July 22-26, 2007)

    Energy Technology Data Exchange (ETDEWEB)

    Anthony M. Dean

    2008-04-01

    Microbial Population Biology covers a diverse range of cutting edge issues in the microbial sciences and beyond. Firmly founded in evolutionary biology and with a strongly integrative approach, past meetings have covered topics ranging from the dynamics and genetics of adaptation to the evolution of mutation rate, community ecology, evolutionary genomics, altruism, and epidemiology. This meeting is never dull: some of the most significant and contentious issues in biology have been thrashed out here. We anticipate the 2007 meeting being no exception. The final form of the 2007 meeting is yet to be decided, but the following topics are likely to be included: evolutionary emergence of infectious disease and antibiotic resistance, genetic architecture and implications for the evolution of microbial populations, ageing in bacteria, biogeography, evolution of symbioses, the role of microbes in ecosystem function, and ecological genomics.

  7. The effects of water potential on some microbial populations and ...

    African Journals Online (AJOL)

    The effects of water potential on some microbial populations and decrease kinetic of organic carbon in soil treated with cow manure under laboratory conditions. ... Fourth irrigation treatment was drying-rewetting cycle (D-W) between -0.3 to -15 bars. After 0, 10, 20, 40, 60 and 90 days of incubation, soils were sampled for ...

  8. Microbial control of caged population of Zonocerus variegatus using ...

    African Journals Online (AJOL)

    Microbial control of caged populations of Zonocerus variegatus was carried out using indigenous fungal entomopathogens isolated from the grasshopper's cadaver. Bioassay response indicated a dose-dependent mortality coupled with drastic reduction in food consumption among spores infected grasshoppers. Lethal time ...

  9. Effect of four herbicides on microbial population, soil organic matter ...

    African Journals Online (AJOL)

    The effect of four herbicides (atrazine, primeextra, paraquat and glyphosate) on soil microbial population, soil organic matter and dehydrogenase activity was assessed over a period of six weeks. Soil samples from cassava farms were treated with herbicides at company recommended rates. Soil dehydrogenase activity was ...

  10. Experimental demonstration of an Allee effect in microbial populations.

    Science.gov (United States)

    Kaul, RajReni B; Kramer, Andrew M; Dobbs, Fred C; Drake, John M

    2016-04-01

    Microbial populations can be dispersal limited. However, microorganisms that successfully disperse into physiologically ideal environments are not guaranteed to establish. This observation contradicts the Baas-Becking tenet: 'Everything is everywhere, but the environment selects'. Allee effects, which manifest in the relationship between initial population density and probability of establishment, could explain this observation. Here, we experimentally demonstrate that small populations of Vibrio fischeri are subject to an intrinsic demographic Allee effect. Populations subjected to predation by the bacterivore Cafeteria roenbergensis display both intrinsic and extrinsic demographic Allee effects. The estimated critical threshold required to escape positive density-dependence is around 5, 20 or 90 cells ml(-1)under conditions of high carbon resources, low carbon resources or low carbon resources with predation, respectively. This work builds on the foundations of modern microbial ecology, demonstrating that mechanisms controlling macroorganisms apply to microorganisms, and provides a statistical method to detect Allee effects in data. © 2016 The Author(s).

  11. Microbial Populations of Stony Meteorites: Substrate Controls on First Colonizers

    Directory of Open Access Journals (Sweden)

    Alastair W. Tait

    2017-06-01

    Full Text Available Finding fresh, sterilized rocks provides ecologists with a clean slate to test ideas about first colonization and the evolution of soils de novo. Lava has been used previously in first colonizer studies due to the sterilizing heat required for its formation. However, fresh lava typically falls upon older volcanic successions of similar chemistry and modal mineral abundance. Given enough time, this results in the development of similar microbial communities in the newly erupted lava due to a lack of contrast between the new and old substrates. Meteorites, which are sterile when they fall to Earth, provide such contrast because their reduced and mafic chemistry commonly differs to the surfaces on which they land; thus allowing investigation of how community membership and structure respond to this new substrate over time. We conducted 16S rRNA gene analysis on meteorites and soil from the Nullarbor Plain, Australia. We found that the meteorites have low species richness and evenness compared to soil sampled from directly beneath each meteorite. Despite the meteorites being found kilometers apart, the community structure of each meteorite bore more similarity to those of other meteorites (of similar composition than to the community structure of the soil on which it resided. Meteorites were dominated by sequences that affiliated with the Actinobacteria with the major Operational Taxonomic Unit (OTU classified as Rubrobacter radiotolerans. Proteobacteria and Bacteroidetes were the next most abundant phyla. The soils were also dominated by Actinobacteria but to a lesser extent than the meteorites. We also found OTUs affiliated with iron/sulfur cycling organisms Geobacter spp. and Desulfovibrio spp. This is an important finding as meteorites contain abundant metal and sulfur for use as energy sources. These ecological findings demonstrate that the structure of the microbial community in these meteorites is controlled by the substrate, and will not

  12. Molecular characterization of microbial population dynamics during sildenafil citrate degradation.

    Science.gov (United States)

    De Felice, Bruna; Argenziano, Carolina; Guida, Marco; Trifuoggi, Marco; Russo, Francesca; Condorelli, Valerio; Inglese, Mafalda

    2009-02-01

    Little is known about pharmaceutical and personal care products pollutants (PPCPs), but there is a growing interest in how they might impact the environment and microbial communities. The widespread use of Viagra (sildenafil citrate) has attracted great attention because of the high usage rate, the unpredictable disposal and the unknown potential effects on wildlife and the environment. Until now information regarding the impact of Viagra on microbial community in water environment has not been reported. In this research, for the first time, the genetic profile of the microbial community, developing in a Viagra polluted water environment, was evaluated by means of the 16S and 18S rRNA genes, for bacteria and fungi, respectively, amplified by polymerase chain reaction (PCR) and separated using the denaturing gradient gel electrophoresis (DGGE) technique. The DGGE results revealed a complex microbial community structure with most of the population persisting throughout the experimental period. DNA sequences from bands observed in the different denaturing gradient gel electrophoresis profiles exhibited the highest degree of identity to uncultured bacteria and fungi found previously mainly in polluted environmental and treating bioreactors. Biotransformation ability of sildenafil citrate by the microbial pool was studied and the capability of these microorganisms to detoxify a polluted water ecosystem was assessed. The bacterial and fungal population was able to degrade sildenafil citrate entirely. Additionally, assays conducted on Daphnia magna, algal growth inhibition assay and cell viability determination on HepG2 human cells showed that biotransformation products obtained from the bacterial growth was not toxic. The higher removal efficiency for sildenafil citrate and the lack of toxicity by the biotransformation products obtained showed that the microbial community identified here represented a composite population that might have biotechnological relevance to

  13. Evolutionary Dynamics and Diversity in Microbial Populations

    Science.gov (United States)

    Thompson, Joel; Fisher, Daniel

    2013-03-01

    Diseases such as flu and cancer adapt at an astonishing rate. In large part, viruses and cancers are so difficult to prevent because they are continually evolving. Controlling such ``evolutionary diseases'' requires a better understanding of the underlying evolutionary dynamics. It is conventionally assumed that adaptive mutations are rare and therefore will occur and sweep through the population in succession. Recent experiments using modern sequencing technologies have illuminated the many ways in which real population sequence data does not conform to the predictions of conventional theory. We consider a very simple model of asexual evolution and perform simulations in a range of parameters thought to be relevant for microbes and cancer. Simulation results reveal complex evolutionary dynamics typified by competition between lineages with different sets of adaptive mutations. This dynamical process leads to a distribution of mutant gene frequencies different than expected under the conventional assumption that adaptive mutations are rare. Simulated gene frequencies share several conspicuous features with data collected from laboratory-evolved yeast and the worldwide population of influenza.

  14. Microbial fuel cell based on electroactive sulfate-reducing biofilm

    International Nuclear Information System (INIS)

    Angelov, Anatoliy; Bratkova, Svetlana; Loukanov, Alexandre

    2013-01-01

    Highlights: ► Regulation and management of electricity generation by variation of residence time. ► Design of microbial fuel cell based on electroactive biofilm on zeolite. ► Engineering solution for removing of the obtained elemental sulfur. - abstract: A two chambered laboratory scale microbial fuel cell (MFC) has been developed, based on natural sulfate-reducing bacterium consortium in electroactive biofilm on zeolite. The MFC utilizes potassium ferricyanide in the cathode chamber as an electron acceptor that derives electrons from the obtained in anode chamber H 2 S. The molecular oxygen is finally used as a terminal electron acceptor at cathode compartment. The generated power density was 0.68 W m −2 with current density of 3.2 A m −2 at 150 Ω electrode resistivity. The hydrogen sulfide itself is produced by microbial dissimilative sulfate reduction process by utilizing various organic substrates. Finally, elemental sulfur was identified as the predominant final oxidation product in the anode chamber. It was removed from MFC through medium circulation and gathering in an external tank. This report reveals dependence relationship between the progress of general electrochemical parameters and bacterial sulfate-reduction rate. The presented MFC design can be used for simultaneous sulfate purification of mining drainage wastewater and generation of renewable electricity

  15. Strongly Deterministic Population Dynamics in Closed Microbial Communities

    Directory of Open Access Journals (Sweden)

    Zak Frentz

    2015-10-01

    Full Text Available Biological systems are influenced by random processes at all scales, including molecular, demographic, and behavioral fluctuations, as well as by their interactions with a fluctuating environment. We previously established microbial closed ecosystems (CES as model systems for studying the role of random events and the emergent statistical laws governing population dynamics. Here, we present long-term measurements of population dynamics using replicate digital holographic microscopes that maintain CES under precisely controlled external conditions while automatically measuring abundances of three microbial species via single-cell imaging. With this system, we measure spatiotemporal population dynamics in more than 60 replicate CES over periods of months. In contrast to previous studies, we observe strongly deterministic population dynamics in replicate systems. Furthermore, we show that previously discovered statistical structure in abundance fluctuations across replicate CES is driven by variation in external conditions, such as illumination. In particular, we confirm the existence of stable ecomodes governing the correlations in population abundances of three species. The observation of strongly deterministic dynamics, together with stable structure of correlations in response to external perturbations, points towards a possibility of simple macroscopic laws governing microbial systems despite numerous stochastic events present on microscopic levels.

  16. Nitrogen Deposition Reduces Decomposition Rates Through Shifts in Microbial Community Composition and Function

    Science.gov (United States)

    Waldrop, M.; Zak, D.; Sinsabaugh, R.

    2002-12-01

    Atmospheric nitrogen (N) deposition may alter soil biological activity in northern hardwood forests by repressing phenol oxidase enzyme activity and altering microbial community composition, thereby slowing decomposition and increasing the export of phenolic compounds. We tested this hypothesis by adding 13C-labelled cellobiose, vanillin, and catechol to control and N fertilized soils (30 and 80 kg ha-1) collected from three forests; two dominated by Acer Saccharum and one dominated by Quercus Alba and Quercus Velutina. While N deposition increased total microbial respiration, it decreased soil oxidative enzyme activities, resulting in slower degradation rates of all compounds, and larger DOC pools. This effect was larger in the oak forest, where fungi dominate C-cycling processes. DNA and 13C-phospolipid analyses showed that N addition altered the fungal community and reduced the activity of fungal and bacterial populations in soil, potentially explaining reduced soil enzyme activities and incomplete decomposition.

  17. Effect of inclusion of different levels of silage on rumen microbial population and microbial protein synthesis in dairy steers fed on rice straw

    Directory of Open Access Journals (Sweden)

    Thien Truong Giang Nguyen

    2017-02-01

    Full Text Available Objective Leucaena leucocephala (Leucaena is a perennial tropical legume that can be directly grazed or harvested and offered to ruminants as hay, silage, or fresh. However, Leucaena contain phenolic compounds, which are considered anti-nutritional factors as these may reduce intake, digestibility and thus animal performance. Therefore, the objective of this experiment was to determine effects of Leucaena silage (LS feeding levels on rumen microbial populations, N-balance and microbial protein synthesis in dairy steers. Methods Four, rumen fistulated dairy steers with initial weight of 167±12 kg were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. Treatments were as followings: T1 = untreated rice straw (RS; Control, T2 = 70% RS+30% LS, T3 = 40% RS+60% LS, and T4 = 100% LS. Dairy steers were fed rice straw and LS ad libitum and supplemented with concentrate at 0.2% of body weight/d. Results Results revealed that the rumen microbial population, especially cellulolytic, proteolytic bacteria and fungal zoospores were enhanced in steers that received 60% of LS (p0.05. Protozoal population was linearly decreased with increasing level of LS (p<0.05. Moreover, N-balance and microbial protein synthesis were enhanced by LS feeding (p<0.05 and were the highest in 60% LS group. Conclusion Based on this study, it could be concluded that replacement of RS with 60% LS significantly improved microbial population and microbial protein synthesis in diary steers.

  18. [Formation of microbial populations on the surface of protective coatings].

    Science.gov (United States)

    Kopteva, Zh P; Zanina, V V; Piliashenko-Novokhatnyĭ, A I; Kopteva, A E; Kozlova, I A

    2001-01-01

    Formation of microbial cenosis on the surface of polyethylene-, polyurethane- and oil-bitumen-based protective coatings was studied in dynamics during 1, 3, 7, 14 and 21 days. It has been shown that the biofilm was formed on the protective materials during 14 days and consisted of ammonifying, denitrifying, hydrocarbon-oxidizing and sulphate-reducing bacteria referred to Pseudomonas, Arthrobacter, Bacillus and Kesulfovibrio genera. The bacteria which form the biofilm on coatings possess high denitrifying and sulphate-reducing activities. Corrosion inhibitors-biocydes, introduced in composition of oil-bitumen coatings suppressed growth and metabolic activity of corrosion-active bacteria.

  19. Effect of oil spill on the microbial population in Andaman Sea around Nicobar Island

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, R.

    The microbial studiees of the follow up cruise by FORV Sagar Sampada (cruise No. 113), 9 months after the oil spill in the Andaman Sea due to accident of VLCC Maersk Navigator revealed disturbance in the natural microbial population. Higher...

  20. Microcomputer package for statistical analysis of microbial populations.

    Science.gov (United States)

    Lacroix, J M; Lavoie, M C

    1987-11-01

    We have developed a Pascal system to compare microbial populations from different ecological sites using microcomputers. The values calculated are: the coverage value and its standard error, the minimum similarity and the geometric similarity between two biological samples, and the Lambda test consisting of calculating the ratio of the mean similarity between two subsets by the mean similarity within subsets. This system is written for Apple II, IBM or compatible computers, but it can work for any computer which can use CP/M, if the programs are recompiled for such a system.

  1. BSocial: Deciphering Social Behaviors within Mixed Microbial Populations

    Directory of Open Access Journals (Sweden)

    Jessica Purswani

    2017-05-01

    Full Text Available Ecosystem functionality depends on interactions among populations, of the same or different taxa, and these are not just the sum of pairwise interactions. Thus, know-how of the social interactions occurring in mixed-populations are of high interest, however they are commonly unknown due to the limitations posed in tagging each population. The limitations include costs/time in tediously fluorescent tagging, and the number of different fluorescent tags. Tag-free strategies exist, such as high-throughput sequencing, but ultimately both strategies require the use of expensive machinery. Our work appoints social behaviors on individual strains in mixed-populations, offering a web-tool (BSocialhttp://m4m.ugr.es/BSocial.html for analyzing the community framework. Our quick and cheap approach includes the periodic monitoring of optical density (OD from a full combinatorial testing of individual strains, where number of generations and growth rate are determined. The BSocial analyses then enable us to determine how the addition/absence of a particular species affects the net productivity of a microbial community and use this to select productive combinations, i.e., designate their social effect on a general community. Positive, neutral, or negative assignations are applied to describe the social behavior within the community by comparing fitness effects of the community against the individual strain. The usefulness of this tool for selection of optimal inoculum in biofilm-based methyl tert-butyl ether (MTBE bioremediation was demonstrated. The studied model uses seven bacterial strains with diverse MTBE degradation/growth capacities. Full combinatorial testing of seven individual strains (triplicate tests of 127 combinations were implemented, along with MTBE degradation as the desired function. Sole observation of highest species fitness did not render the best functional outcome, and only when strains with positive and neutral social assignations were

  2. MICROBIAL DEGRADATION OF SEVEN AMIDES BY SUSPENDED BACTERIAL POPULATIONS

    Science.gov (United States)

    Microbial transformation rate constants were determined for seven amides in natural pond water. A second-order mathematical rate expression served as the model for describing the microbial transformation. Also investigated was the relationship between the infrared spectra and the...

  3. Shifts in microbial populations in Rusitec fermenters as affected by the type of diet and impact of the method for estimating microbial growth (15N v. microbial DNA).

    Science.gov (United States)

    Mateos, I; Ranilla, M J; Saro, C; Carro, M D

    2017-11-01

    Rusitec fermenters are in vitro systems widely used to study ruminal fermentation, but little is known about the microbial populations establishing in them. This study was designed to assess the time evolution of microbial populations in fermenters fed medium- (MC; 50% alfalfa hay : concentrate) and high-concentrate diets (HC; 15 : 85 barley straw : concentrate). Samples from solid (SOL) and liquid (LIQ) content of fermenters were taken immediately before feeding on days 3, 8 and 14 of incubation for quantitative polymerase chain reaction and automated ribosomal intergenic spacer analysis analyses. In SOL, total bacterial DNA concentration and relative abundance of Ruminococcus flavefaciens remained unchanged over the incubation period, but protozoal DNA concentration and abundance of Fibrobacter succinogenes, Ruminococcus albus and fungi decreased and abundance of methanogenic archaea increased. In LIQ, total bacterial DNA concentration increased with time, whereas concentration of protozoal DNA and abundance of methanogens and fungi decreased. Diet×time interactions were observed for bacterial and protozoal DNA and relative abundance of F. succinogenes and R. albus in SOL, as well as for protozoal DNA in LIQ. Bacterial diversity in SOL increased with time, but no changes were observed in LIQ. The incubated diet influenced all microbial populations, with the exception of total bacteria and fungi abundance in LIQ. Bacterial diversity was higher in MC-fed than in HC-fed fermenters in SOL, but no differences were detected in LIQ. Values of pH, daily production of volatile fatty acids and CH4 and isobutyrate proportions remained stable over the incubation period, but other fermentation parameters varied with time. The relationships among microbial populations and fermentation parameters were in well agreement with those previously reported in in vivo studies. Using 15N as a microbial marker or quantifying total microbial DNA for estimating microbial protein synthesis

  4. Physiological heterogeneities in microbial populations and implications for physical stress tolerance

    DEFF Research Database (Denmark)

    Carlquist, Magnus; Fernandes, Rita Lencastre; Helmark, Søren

    2012-01-01

    Background: Traditionally average values of the whole population are considered when analysing microbial cell cultivations. However, a typical microbial population in a bioreactor is heterogeneous in most phenotypes measurable at a single-cell level. There are indications that such heterogeneity...

  5. Microbial population changes during bioremediation of an experimental oil spill

    International Nuclear Information System (INIS)

    MacNaughton, S.J.; Stephen, J.R.; Chang, Y.J.; Davis, G.A.; White, D.C.; Oak Ridge National Lab., TN

    1999-01-01

    Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil spill. Four treatments (no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum) were applied. In situ microbial community structures were monitored by phospholipid fatty acid (PLFA) analysis and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) to (i) identify the bacterial community members responsible for the decontamination of the site and (ii) define an end point for the removal of the hydrocarbon substrate. The results of PLFA analysis demonstrated a community shift in all plots from primarily eukaryotic biomass to gram-negative bacterial biomass with time. PLFA profiles from the oiled plots suggested increased gram-negative biomass and adaptation to metabolic stress compared to unoiled controls. DGGE analysis of untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment. This banding pattern disappeared in all oiled plots, indicating that the structure and diversity of the dominant bacterial community changed substantially. No consistent differences were detected between nutrient-amended and indigenous inoculum-treated plots, but both differed from the oil-only plots. Prominent bands were excised for sequence analysis and indicated that oil treatment encouraged the growth of gram-negative microorganisms within the α-proteobacteria and Flexibacter-Cytophaga-Bacteroides phylum. α-Proteobacteria were never detected in unoiled controls. PLFA analysis indicated that by week 14 the microbial community structures of the oiled plots were becoming similar to those of the unoiled controls from the same time point, but DGGE analysis suggested that major differences in the bacterial communities remained

  6. Effects of Alachlor and Metolachlor on Microbial Populations in the Soil

    Directory of Open Access Journals (Sweden)

    Ismail, B. S.

    2005-01-01

    Full Text Available A study of the impact of two acetanilide herbicides, viz. alachlor and metolachlor on bacterial and fungal populations and biomass in the Sungai Buluh soil series samples was carried out under laboratory conditions. The effects of the two herbicides were monitored for 70 days under ambient conditions. Metolachlor caused greater reduction in bacterial counts than on fungal populations. There was approximately 75% reduction in bacterial counts 14 days after treatment (DAT with 2 µg/g metolachlor. Alachlor however was less toxic to bacterial and fungal populations. Alachlor caused a reduction in bacterial counts at 7 and 14 DAT with 2µg/g or above. Fungal population decreased significantly in the presence of 20 µg/g alachlor at 7 DAT but no further effects were observed as the incubation period was prolonged. The study showed that the microbial biomass immediately decreased significantly in the presence of 2 µg/g or more of metolachlor at 0 and 28 DAT. Alachlor, on the other hands, at the lowest experimental dose of 2 µg/g reduced the microbial biomass almost immediately upon incubation, but had no further effects when the incubation period was prolonged.

  7. Anomalous electrical signals associated with microbial activity: Results from Iron and Nitrate-Reducing Columns

    Science.gov (United States)

    Aaron, R. B.; Zheng, Q.; Flynn, P.; Singha, K.; Brantley, S.

    2008-12-01

    Three flow-through columns outfitted with Ag/AgCl electrodes were constructed to test the effects of different microbial processes on the geophysical measurements of self potential (SP), bulk electrical conductivity (σ b), and induced polarization (IP). The columns were filled with sieved, Fe-bearing subsurface sediment from the Delmarva Peninsula near Oyster, VA, inoculated (9:1 ratio) with a freshly-collected, shallow subsurface sediment from a wetland floodplain (Dorn Creek) near Madison, WI. Each of the columns was fed anoxic and sterile PIPES buffered artificial groundwater (PBAGW) containing different concentrations of acetate and nitrate. The medium fed to Column 1 (nitrate-reducing) was amended with 100 μM acetate and 2 mM nitrate. Column 2 (iron-reducing) was run with PBAGW containing 1.0 mM acetate and 0 mM nitrate. Column 3 (alternating redox state) was operated under conditions designed to alternately stimulate nitrate-reducing and iron-reducing populations to provide conditions, i.e., the presence of both nitrate and microbially-produced Fe(II), that would allow growth of nitrate-dependent Fe(II)-oxidizing populations. We operated Column 3 with a cycling strategy of 14-18 days of high C medium (1 mM acetate and 100 μ M nitrate) followed by 14-18 days of low C medium (100 μ M acetate and 2 mM nitrate). Effluent chemistry (NO3-, NO2-, NH4+, acetate, and Fe2+) was sampled daily for four months so as to be concurrent with the electrical measurements. We observed chemical evidence of iron reduction (dissolved [Fe(II)] = 0.2mM) in the effluent from the iron reduction and alternating redox columns. Chemical depletion of NO3- ([NO3-] ranged from 1 to 0.02mM), the production of NO2-, and possible production of NH4+ (0.2 mM) was observed in the nitrate reducing column as well as the alternating redox column. All three columns displayed loss of acetate as microbial activity progressed. σ b remained constant in the alternating redox column (~0.15 S

  8. Determining the specific microbial populations and their spatial distribution within the stromatolite ecosystem of Shark Bay.

    Science.gov (United States)

    Goh, Falicia; Allen, Michelle A; Leuko, Stefan; Kawaguchi, Tomohiro; Decho, Alan W; Burns, Brendan P; Neilan, Brett A

    2009-04-01

    The stromatolites at Shark Bay, Western Australia, are analogues of some of the oldest evidence of life on Earth. The aim of this study was to identify and spatially characterize the specific microbial communities associated with Shark Bay intertidal columnar stromatolites. Conventional culturing methods and construction of 16S rDNA clone libraries from community genomic DNA with both universal and specific PCR primers were employed. The estimated coverage, richness and diversity of stromatolite microbial populations were compared with earlier studies on these ecosystems. The estimated coverage for all clone libraries indicated that population coverage was comprehensive. Phylogenetic analyses of stromatolite and surrounding seawater sequences were performed in ARB with the Greengenes database of full-length non-chimaeric 16S rRNA genes. The communities identified exhibited extensive diversity. The most abundant sequences from the stromatolites were alpha- and gamma-proteobacteria (58%), whereas the cyanobacterial community was characterized by sequences related to the genera Euhalothece, Gloeocapsa, Gloeothece, Chroococcidiopsis, Dermocarpella, Acaryochloris, Geitlerinema and Schizothrix. All clones from the archaeal-specific clone libraries were related to the halophilic archaea; however, no archaeal sequence was identified from the surrounding seawater. Fluorescence in situ hybridization also revealed stromatolite surfaces to be dominated by unicellular cyanobacteria, in contrast to the sub-surface archaea and sulphate-reducing bacteria. This study is the first to compare the microbial composition of morphologically similar stromatolites over time and examine the spatial distribution of specific microorganismic groups in these intertidal structures and the surrounding seawater at Shark Bay. The results provide a platform for identifying the key microbial physiology groups and their potential roles in modern stromatolite morphogenesis and ecology.

  9. Enumeration of microbial populations in radioactive environments by epifluorescence microscopy

    International Nuclear Information System (INIS)

    Pansoy-Hjelvik, M.E.; Strietelmeier, B.A.; Paffett, M.T.

    1997-01-01

    Epifluorescence microscopy was utilized to enumerate halophilic bacterial populations in two studies involving inoculated, actual waste/brine mixtures and pure brine solutions. The studies include an initial set of experiments designed to elucidate potential transformations of actinide-containing wastes under salt-repository conditions, including microbially mediated changes. The first study included periodic enumeration of bacterial populations of a mixed inoculum initially added to a collection of test containers. The contents of the test containers are the different types of actual radioactive waste that could potentially be stored in nuclear waste repositories in a salt environment. The transuranic waste was generated from materials used in actinide laboratory research. The results show that cell numbers decreased with time. Sorption of the bacteria to solid surfaces in the test system is discussed as a possible mechanism for the decrease in cell numbers. The second study was designed to determine radiological and/or chemical effects of 239 Pu, 243 Am, 237 Np, 232 Th and 238 U on the growth of pure and mixed anaerobic, denitrifying bacterial cultures in brine media. Pu, Am, and Np isotopes at concentrations of ≤1x10 -6 M , ≤5x10 -6 M and ≤5x10 -4 M respectively, and Th and U isotopes ≤4x10 -3 M were tested in these media. The results indicate that high concentrations of certain actinides affected both the bacterial growth rate and morphology. However, relatively minor effects from Am were observed at all tested concentrations with the pure culture

  10. Reduced Oral Microbial Diversity in Individuals Harbor Periodontal Diseases

    Directory of Open Access Journals (Sweden)

    Jinghua Sun

    2012-02-01

    Full Text Available Introduction: Bacteria colonize a variety of surfaces of the hu-man body. The bacterial diversity in the oral cavity is estimated to be more than 700 different species. The oral cavity is home to microbial communities, with important implications for human health and disease. Oral microbial flora is responsible for two major human infectious diseases of the oral cavity, dental caries and periodontal diseases. From the clinical samples, previously, using polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE technique, we found a significantly greater diversity of oral microbes in caries-free individuals compared with caries-active individuals. The hypothesis: We hypothesize that a greater diversity of indigenous bacteria inhabits a healthy oral environment, and that a sig-nificant proportion of oral biota may be absent, suppressed, or replaced in a periodontal diseases environment. Evaluation of the hypothesis: The microbiota undergoes a transition from a commensal to a pathogenic relationship with the host due to factors that trigger a shift in the proportions of resident microorganisms. If our hypothesis is true, many techniques which were used to detect the oral bacterial diversity can be used in diagnosis and prognosis of periodontal diseases.

  11. Molecular Characterization of Swine Manure Lagoon Microbial and Antibiotic Resistant Populations

    Science.gov (United States)

    Background: The differences in swine manure lagoon effluent based on differing management styles or approaches such as different stages of swine rearing determines the presence of variable antibiotic resistance determinants and functional microbial populations. These concerns determine the suitabil...

  12. Population density of Beauveria bassiana in soil under the action of fungicides and native microbial populations

    Directory of Open Access Journals (Sweden)

    Flávia Barbosa Soares

    2017-08-01

    Full Text Available This study investigated whether populations of naturally-occurring soil bacteria, fungi and actinomycetes influence the effect of fungicides on the survival and growth of Beauveria bassiana. The toxicity of methyl thiophanate, pyraclostrobin, mancozeb and copper oxychloride at the recommended doses was analyzed in culture medium and in soil inoculated with fungus at various time points after addition of fungicides. All fungicides completely inhibited the growth and sporulation of B. bassiana in the culture medium. The fungicides were less toxic in soil, emphasizing the action of the microbial populations, which interfered with the toxic effects of these products to the fungus. Actinomycetes had the greatest influence on the entomopathogen, inhibiting it or degrading the fungicides to contribute to the survival and growth of B. bassiana in soil. Native populations of fungi and bacteria had a smaller influence on the population density of B. bassiana and the action of fungicides towards entomopathogen. The toxic effect of the fungicides was greater when added to the soil one hour before or after inoculation than at 48h after inoculation.

  13. Microbial community analysis of perchlorate-reducing cultures growing on zero-valent iron

    International Nuclear Information System (INIS)

    Son, Ahjeong; Schmidt, Carl J.; Shin, Hyejin; Cha, Daniel K.

    2011-01-01

    Anaerobic microbial mixed cultures demonstrated its ability to completely remove perchlorate in the presence of zero-valent iron. In order to understand the major microbial reaction in the iron-supported culture, community analysis comprising of microbial fatty acids and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) techniques was performed for perchlorate reducing cultures. Analysis of fatty acid methyl esters (FAMEs) and subsequent principal component analysis (PCA) showed clear distinctions not only between iron-supported perchlorate reducing culture and seed bacteria, but also among perchlorate-reducing cultures receiving different electron donors. The DGGE pattern targeting the chlorite dismutase (cld) gene showed that iron-supported perchlorate reducing culture is similar to hydrogen-fed cultures as compared to acetate-fed culture. The phylogenetic tree suggested that the dominant microbial reaction may be a combination of the autotrophic and heterotrophic reduction of perchlorate. Both molecular and chemotaxonomic experimental results support further understanding in the function of zero-valent iron as an adequate electron source for enhancing the microbial perchlorate reduction in natural and engineered systems.

  14. Microbial community analysis of perchlorate-reducing cultures growing on zero-valent iron

    Energy Technology Data Exchange (ETDEWEB)

    Son, Ahjeong, E-mail: ason@auburn.edu [Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Schmidt, Carl J. [Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716 (United States); Shin, Hyejin [Department of Mathematics and Statistics, Auburn University, Auburn, AL 36849 (United States); Cha, Daniel K. [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States)

    2011-01-30

    Anaerobic microbial mixed cultures demonstrated its ability to completely remove perchlorate in the presence of zero-valent iron. In order to understand the major microbial reaction in the iron-supported culture, community analysis comprising of microbial fatty acids and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) techniques was performed for perchlorate reducing cultures. Analysis of fatty acid methyl esters (FAMEs) and subsequent principal component analysis (PCA) showed clear distinctions not only between iron-supported perchlorate reducing culture and seed bacteria, but also among perchlorate-reducing cultures receiving different electron donors. The DGGE pattern targeting the chlorite dismutase (cld) gene showed that iron-supported perchlorate reducing culture is similar to hydrogen-fed cultures as compared to acetate-fed culture. The phylogenetic tree suggested that the dominant microbial reaction may be a combination of the autotrophic and heterotrophic reduction of perchlorate. Both molecular and chemotaxonomic experimental results support further understanding in the function of zero-valent iron as an adequate electron source for enhancing the microbial perchlorate reduction in natural and engineered systems.

  15. Microbial biotransformation of DON: molecular basis for reduced toxicity

    Science.gov (United States)

    Pierron, Alix; Mimoun, Sabria; Murate, Leticia S.; Loiseau, Nicolas; Lippi, Yannick; Bracarense, Ana-Paula F. L.; Schatzmayr, Gerd; He, Jian Wei; Zhou, Ting; Moll, Wulf-Dieter; Oswald, Isabelle P.

    2016-07-01

    Bacteria are able to de-epoxidize or epimerize deoxynivalenol (DON), a mycotoxin, to deepoxy-deoxynivalenol (deepoxy-DON or DOM-1) or 3-epi-deoxynivalenol (3-epi-DON), respectively. Using different approaches, the intestinal toxicity of 3 molecules was compared and the molecular basis for the reduced toxicity investigated. In human intestinal epithelial cells, deepoxy-DON and 3-epi-DON were not cytotoxic, did not change the oxygen consumption or impair the barrier function. In intestinal explants, exposure for 4 hours to 10 μM DON induced intestinal lesions not seen in explants treated with deepoxy-DON and 3-epi-DON. A pan-genomic transcriptomic analysis was performed on intestinal explants. 747 probes, representing 323 genes, were differentially expressed, between DON-treated and control explants. By contrast, no differentially expressed genes were observed between control, deepoxy-DON and 3-epi-DON treated explants. Both DON and its biotransformation products were able to fit into the pockets of the A-site of the ribosome peptidyl transferase center. DON forms three hydrogen bonds with the A site and activates MAPKinases (mitogen-activated protein kinases). By contrast deepoxy-DON and 3-epi-DON only form two hydrogen bonds and do not activate MAPKinases. Our data demonstrate that bacterial de-epoxidation or epimerization of DON altered their interaction with the ribosome, leading to an absence of MAPKinase activation and a reduced toxicity.

  16. Microbial Population Dynamics Associated with Crude-Oil Biodegradation in Diverse Soils

    OpenAIRE

    Hamamura, Natsuko; Olson, Sarah H.; Ward, David M.; Inskeep, William P.

    2006-01-01

    Soil bacterial population dynamics were examined in several crude-oil-contaminated soils to identify those organisms associated with alkane degradation and to assess patterns in microbial response across disparate soils. Seven soil types obtained from six geographically distinct areas of the United States (Arizona, Oregon, Indiana, Virginia, Oklahoma, and Montana) were used in controlled contamination experiments containing 2% (wt/wt) crude oil spiked with [1-14C]hexadecane. Microbial populat...

  17. Linking Microbial Ecology to Geochemistry in Sulfate Reducing Systems

    Science.gov (United States)

    Drennan, D. M.; Lee, I.; Landkamer, L.; Almstrand, R.; Figueroa, L. A.; Sharp, J. H.

    2013-12-01

    Sulfate reducing bioreactors (SRBRs) can serve as passive treatment systems for mining influenced waters (MIW). An enhanced understanding of the biogeochemistry and efficacy of SRBRs can be achieved by combining molecular biological and geochemical techniques in both field and column settings. To this end, a spatial and temporal sequence of eight pilot-scale columns were analyzed employing a multidisciplinary approach using ICP-AES, next-generation sequencing, and SEM-EDX to explore the effects of variable substrate on community structure and performance (measured by Zn removal). All pilot scale reactors contained 30% limestone by mass, 7 of the 8 had variable amounts of woodchips, sawdust, and alfalfa hay, and an 8th column where the only carbon source was walnut shells. High throughput sequencing of DNA extracted from liquid in pilot-scale columns reveals, similarly to an analogous field system in Arizona, a dominance of Proteobacteria. However, after the first pore volume, performance differences between substrate permutations emerged, where columns containing exclusively walnut shells or sawdust exhibited a more effective startup and metal removal than did columns containing exclusively woodchips or alfalfa hay. SEM-EDX analysis revealed the initial formation of gypsum (CaSO4) precipitates regardless of substrate. Zn was observed in the presence of Ca, S, and O in some column samples, suggesting there was co-precipitation of Zn and CaSO4. This is congruent with micro-XAS analysis of field data suggesting iron sulfides were co-precipitating with gypsum. A SEM-EDX analysis from a subsequent sampling event (8 months into operation) indicated that precipitation may be shifting to ZnS and ZnCO3. Biplots employing Canonical Correspondence Analysis (CCA) describe how diversity scales with performance and substrate selection, and how community shifts may result in differential performance and precipitation in response to selective pressure of bioreactor material on

  18. Soil biochar amendment shapes the composition of N_2O-reducing microbial communities

    International Nuclear Information System (INIS)

    Harter, Johannes; Weigold, Pascal; El-Hadidi, Mohamed; Huson, Daniel H.; Kappler, Andreas; Behrens, Sebastian

    2016-01-01

    Soil biochar amendment has been described as a promising tool to improve soil quality, sequester carbon, and mitigate nitrous oxide (N_2O) emissions. N_2O is a potent greenhouse gas. The main sources of N_2O in soils are microbially-mediated nitrogen transformation processes such as nitrification and denitrification. While previous studies have focused on the link between N_2O emission mitigation and the abundance and activity of N_2O-reducing microorganisms in biochar-amended soils, the impact of biochar on the taxonomic composition of the nosZ gene carrying soil microbial community has not been subject of systematic study to date. We used 454 pyrosequencing in order to study the microbial diversity in biochar-amended and biochar-free soil microcosms. We sequenced bacterial 16S rRNA gene amplicons as well as fragments of common (typical) nosZ genes and the recently described ‘atypical’ nosZ genes. The aim was to describe biochar-induced shifts in general bacterial community diversity and taxonomic variations among the nosZ gene containing N_2O-reducing microbial communities. While soil biochar amendment significantly altered the 16S rRNA gene-based community composition and structure, it also led to the development of distinct functional traits capable of N_2O reduction containing typical and atypical nosZ genes related to nosZ genes found in Pseudomonas stutzeri and Pedobacter saltans, respectively. Our results showed that biochar amendment can affect the relative abundance and taxonomic composition of N_2O-reducing functional microbial traits in soil. Thus these findings broaden our knowledge on the impact of biochar on soil microbial community composition and nitrogen cycling. - Highlights: • Biochar promoted anaerobic, alkalinity-adapted, and polymer-degrading microbial taxa. • Biochar fostered the development of distinct N_2O-reducing microbial taxa. • Taxonomic shifts among N_2O-reducing microbes might explain lower N_2O emissions.

  19. Soil biochar amendment shapes the composition of N{sub 2}O-reducing microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Harter, Johannes; Weigold, Pascal [Geomicrobiology & Microbial Ecology, Center for Applied Geosciences, University of Tuebingen, Sigwartstr. 10, 72076 Tuebingen (Germany); El-Hadidi, Mohamed; Huson, Daniel H. [Algorithms in Bioinformatics, Center for Bioinformatics, University of Tuebingen, Sand 14, 72076 Tuebingen (Germany); Kappler, Andreas [Geomicrobiology & Microbial Ecology, Center for Applied Geosciences, University of Tuebingen, Sigwartstr. 10, 72076 Tuebingen (Germany); Behrens, Sebastian, E-mail: sbehrens@umn.edu [Geomicrobiology & Microbial Ecology, Center for Applied Geosciences, University of Tuebingen, Sigwartstr. 10, 72076 Tuebingen (Germany); Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, 500 Pillsbury Drive S.E., Minneapolis, MN 55455-0116 (United States); BioTechnology Institute, 140 Gortner Labs, 1479 Gortner Avenue, St. Paul, MN 55108-6106 (United States)

    2016-08-15

    Soil biochar amendment has been described as a promising tool to improve soil quality, sequester carbon, and mitigate nitrous oxide (N{sub 2}O) emissions. N{sub 2}O is a potent greenhouse gas. The main sources of N{sub 2}O in soils are microbially-mediated nitrogen transformation processes such as nitrification and denitrification. While previous studies have focused on the link between N{sub 2}O emission mitigation and the abundance and activity of N{sub 2}O-reducing microorganisms in biochar-amended soils, the impact of biochar on the taxonomic composition of the nosZ gene carrying soil microbial community has not been subject of systematic study to date. We used 454 pyrosequencing in order to study the microbial diversity in biochar-amended and biochar-free soil microcosms. We sequenced bacterial 16S rRNA gene amplicons as well as fragments of common (typical) nosZ genes and the recently described ‘atypical’ nosZ genes. The aim was to describe biochar-induced shifts in general bacterial community diversity and taxonomic variations among the nosZ gene containing N{sub 2}O-reducing microbial communities. While soil biochar amendment significantly altered the 16S rRNA gene-based community composition and structure, it also led to the development of distinct functional traits capable of N{sub 2}O reduction containing typical and atypical nosZ genes related to nosZ genes found in Pseudomonas stutzeri and Pedobacter saltans, respectively. Our results showed that biochar amendment can affect the relative abundance and taxonomic composition of N{sub 2}O-reducing functional microbial traits in soil. Thus these findings broaden our knowledge on the impact of biochar on soil microbial community composition and nitrogen cycling. - Highlights: • Biochar promoted anaerobic, alkalinity-adapted, and polymer-degrading microbial taxa. • Biochar fostered the development of distinct N{sub 2}O-reducing microbial taxa. • Taxonomic shifts among N{sub 2}O-reducing microbes

  20. Effects of post-processing handling and packaging on microbial populations

    International Nuclear Information System (INIS)

    Zagory, D.

    1999-01-01

    The type of produce, process conditions, and prior temperature management will all affect the mix of microorganisms found on fresh produce. Normally, fresh produce will be covered by a complex mix of bacteria, fungi and yeasts that are characteristic of that fruit or vegetable. For example, carrots typically have large numbers of Lactobacillus and other lactic acid bacteria while apples may have relatively large numbers of yeasts. Which of these microorganisms will come to dominate the population will be a function of the make-up of the original population on the product in the field, distribution time, distribution temperature and the atmosphere within the package. Another chief determinant of microbial populations will be the physiological condition of the product. Factors that injure or weaken the plant tissues may be expected to encourage microbial growth while conditions that maintain the physiological integrity of the tissues may be expected to discourage microbial growth. Each of these factors can be expected to affect the make-up of the microbial population in characteristic ways but always constrained by the initial condition of original population makeup. This paper describes which microorganisms are favored by given conditions in order to develop a concept of microbial management designed to favor desirable microbes at the expense of undesirable ones. Particular emphasis will be placed on the effects of modified atmospheres on microorganisms, especially human pathogens

  1. Soil biochar amendment shapes the composition of N2O-reducing microbial communities.

    Science.gov (United States)

    Harter, Johannes; Weigold, Pascal; El-Hadidi, Mohamed; Huson, Daniel H; Kappler, Andreas; Behrens, Sebastian

    2016-08-15

    Soil biochar amendment has been described as a promising tool to improve soil quality, sequester carbon, and mitigate nitrous oxide (N2O) emissions. N2O is a potent greenhouse gas. The main sources of N2O in soils are microbially-mediated nitrogen transformation processes such as nitrification and denitrification. While previous studies have focused on the link between N2O emission mitigation and the abundance and activity of N2O-reducing microorganisms in biochar-amended soils, the impact of biochar on the taxonomic composition of the nosZ gene carrying soil microbial community has not been subject of systematic study to date. We used 454 pyrosequencing in order to study the microbial diversity in biochar-amended and biochar-free soil microcosms. We sequenced bacterial 16S rRNA gene amplicons as well as fragments of common (typical) nosZ genes and the recently described 'atypical' nosZ genes. The aim was to describe biochar-induced shifts in general bacterial community diversity and taxonomic variations among the nosZ gene containing N2O-reducing microbial communities. While soil biochar amendment significantly altered the 16S rRNA gene-based community composition and structure, it also led to the development of distinct functional traits capable of N2O reduction containing typical and atypical nosZ genes related to nosZ genes found in Pseudomonas stutzeri and Pedobacter saltans, respectively. Our results showed that biochar amendment can affect the relative abundance and taxonomic composition of N2O-reducing functional microbial traits in soil. Thus these findings broaden our knowledge on the impact of biochar on soil microbial community composition and nitrogen cycling. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The effects of different uranium concentrations on soil microbial populations and enzymatic activities

    International Nuclear Information System (INIS)

    Bagherifam, S.; Lakziyan, A.; Ahmadi, S. J.; Fotovvat, A.; Rahimi, M. F.

    2010-01-01

    Uranium is an ubiquitous constituent of natural environment with an average concentration of 4 mg/kg in earth crust. However, in local areas it may exceed the normal concentration due to human activities resulting in radionuclide contamination in groundwater and surface soil. The effect of six levels of uranium concentration (0, 50, 100,250. 500 and 1000 mg kg -1 ) on soil phosphatase activities and microbial populations were studied in a completely randomized design as a factorial experiment with three replications. The results showed a significant decrease in phosphatase activity. The result of the experiment suggests that soil microbial populations (bacteria, funji and actinomycetes) decrease by increasing the uranium levels in the soil. Therefore, assessment of soil enzymatic activities and microbial populations can be helpful as a useful index for a better management of uranium and radioactive contaminated soils.

  3. Microbial population changes during bioremediation of an experimental oil spill

    International Nuclear Information System (INIS)

    Venosa, A.D.; Stephen, J.R.; Macnaughton, S.J.; Chang, Y.; White, D.C.

    2000-01-01

    Three crude oil bioremediation techniques were tested in a field experiment in Delaware, United States to determine the progress of natural and accelerated attenuation during a controlled oil spill. The four treatments studied were: no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum. During the first 14 weeks, microbial numbers were high but were steadily declining with no major differences among treatments. However, after the 14 week period, phospholipid fatty acid (PLFA) results showed that the communities shifted from being composed mostly of eukaryotes to gram-negative bacteria. The dominant species diversity changed and increased significantly over 14 weeks. Nutrient addition and the addition of the indigenous inoculum altered the nature of this change. Gas chromatography/mass spectrometry analyses of the oil analytes detected major differences in rates of biodegradation between the amended and unamended natural attenuation plots, but not between the nutrient and inoculum plots. 11 refs., 3 figs

  4. Multitaxon activity profiling reveals differential microbial response to reduced seawater pH and oil pollution.

    Science.gov (United States)

    Coelho, Francisco J R C; Cleary, Daniel F R; Costa, Rodrigo; Ferreira, Marina; Polónia, Ana R M; Silva, Artur M S; Simões, Mário M Q; Oliveira, Vanessa; Gomes, Newton C M

    2016-09-01

    There is growing concern that predicted changes to global ocean chemistry will interact with anthropogenic pollution to significantly alter marine microbial composition and function. However, knowledge of the compounding effects of climate change stressors and anthropogenic pollution is limited. Here, we used 16S and 18S rRNA (cDNA)-based activity profiling to investigate the differential responses of selected microbial taxa to ocean acidification and oil hydrocarbon contamination under controlled laboratory conditions. Our results revealed that a lower relative abundance of sulphate-reducing bacteria (Desulfosarcina/Desulfococcus clade) due to an adverse effect of seawater acidification and oil hydrocarbon contamination (reduced pH-oil treatment) may be coupled to changes in sediment archaeal communities. In particular, we observed a pronounced compositional shift and marked reduction in the prevalence of otherwise abundant operational taxonomic units (OTUs) belonging to the archaeal Marine Benthic Group B and Marine Hydrothermal Vent Group (MHVG) in the reduced pH-oil treatment. Conversely, the abundance of several putative hydrocarbonoclastic fungal OTUs was higher in the reduced pH-oil treatment. Sediment hydrocarbon profiling, furthermore, revealed higher concentrations of several alkanes in the reduced pH-oil treatment, corroborating the functional implications of the structural changes to microbial community composition. Collectively, our results advance the understanding of the response of a complex microbial community to the interaction between reduced pH and anthropogenic pollution. In future acidified marine environments, oil hydrocarbon contamination may alter the typical mixotrophic and k-/r-strategist composition of surface sediment microbiomes towards a more heterotrophic state with lower doubling rates, thereby impairing the ability of the ecosystem to recover from acute oil contamination events. © 2016 John Wiley & Sons Ltd.

  5. Physicochemical and sensory analyses on egg powder irradiated to inactivate Salmonella and reduce microbial load

    International Nuclear Information System (INIS)

    Narvaiz, P.; Lescano, G.; Kairiyama, E.

    1992-01-01

    Egg powder was treated with 0, 2, 5 and 10 kGy of gamma radiation at 20 C to inactivate Salmonella and to stabilize its microbial load. Microbial, physicochemical and sensory determinations were performed during 4 months of storage to select the optimal radiation dose to attain the objective without significantly reducing egg quality. Microbial results show that 2.0 kGy inactivated Salmonella and reduced microbial load to levels below those stipulated by the Argentine regulations. Physicochemical determinations of egg powder extracts for peroxide number, spectrophotometric measurements in the visible and ultraviolet regions, functional properties on sponge cakes made with egg powder (height, compression-relaxation cycle parameters), foam stability and viscosity showed that gamma radiation at the dose of 2 kGy, did not cause significant changes in these parameters. Higher radiation doses (5 and 10 kGy) did increase rancidity, pigment loss and protein chain scission. Sensory determinations performed on egg powder, and on cakes manufactured with it, agreed with the physicochemical results. After 110 storage days, 2 kGy was the most suitable of the tested doses

  6. Aerobic Microbial Community of Insectary Population of Phlebotomus papatasi.

    Directory of Open Access Journals (Sweden)

    Naseh Maleki-Ravasan

    2014-06-01

    Full Text Available Microbes particularly bacteria presenting in the gut of haematophagous insects may have an important role in the epidemiology of human infectious disease.The microbial flora of gut and surrounding environmental of a laboratory strain of Phlebotomus papatasi, the main vector of Zoonotic Cutaneous Leishmaniasis (ZCL in the old world, was investigated. Biochemical reactions and 16s rDNA sequencing of the isolated bacteria against 24 sugars and amino acids were used for bacteria species identification. Common mycological media used for fungi identification as well.Most isolates belonged to the Enterobacteriaceae, a large, heterogeneous group of gram-negative rods whose natural habitat is the intestinal tract of humans and animals. Enterobacteriaceae groups included Edwardsiella, Enterobacter, Escherichia, Klebsiella, Kluyvera, Leminorella, Pantoea, Proteus, Providencia, Rahnella, Serratia, Shigella, Tatumella, and Yersinia and non Enterobacteriaceae groups included Bacillus, Staphylococcus and Pseudomonas. The most prevalent isolates were Proteus mirabilis and P. vulgaris. These saprophytic and swarming motile bacteria were isolated from all immature, pupae, and mature fed or unfed male or female sand flies as well as from larval and adult food sources. Five fungi species were also isolated from sand flies, their food sources and colonization materials where Candida sp. was common in all mentioned sources.Midgut microbiota are increasingly seen as an important factor for modulating vector competence in insect vectors so their possible effects of the mirobiota on the biology of P. papatasi and their roles in the sandfly-Leishmania interaction are discussed.

  7. An age-structured population balance model for microbial dynamics

    Directory of Open Access Journals (Sweden)

    Duarte M.V.E.

    2003-01-01

    Full Text Available This work presents an age-structured population balance model (ASPBM for a bioprocess in a continuous stirred-tank fermentor. It relates the macroscopic properties and dynamic behavior of biomass to the operational parameters and microscopic properties of cells. Population dynamics is governed by two time- and age-dependent density functions for living and dead cells, accounting for the influence of substrate and dissolved oxygen concentrations on cell division, aging and death processes. The ASPBM described biomass and substrate oscillations in aerobic continuous cultures as experimentally observed. It is noteworthy that a small data set consisting of nonsegregated measurements was sufficient to adjust a complex segregated mathematical model.

  8. Cellulose digestion in primitive hexapods: Effect of ingested antibiotics on gut microbial populations and gut cellulase levels in the firebrat,Thermobia domestica (Zygentoma, Lepismatidae).

    Science.gov (United States)

    Treves, D S; Martin, M M

    1994-08-01

    Antibiotic feeding studies were conducted on the firebrat,Thermobia domestica (Zygentoma, Lepismatidae) to determine if the insect's gut cellulases were of insect or microbial origin. Firebrats were fed diets containing either nystatin, metronidazole, streptomycin, tetracycline, or an antibiotic cocktail consisting of all four antibiotics, and then their gut microbial populations and gut cellulase levels were monitored and compared with the gut microbial populations and gut cellulase levels in firebrats feeding on antibiotic-free diets. Each antibiotic significantly reduced the firebrat's gut micro-flora. Nystatin reduced the firebrat's viable gut fungi by 89%. Tetracycline and the antibiotic cocktail reduced the firebrat's viable gut bacteria by 81% and 67%, respectively, and metronidazole, streptomycin, tetracycline, and the antibiotic cocktail reduced the firebrat's total gut flora by 35%, 32%, 55%, and 64%, respectively. Although antibiotics significantly reduced the firebrat's viable and total gut flora, gut cellulase levels in firebrats fed antibiotics were not significantly different from those in firebrats on an antibiotic-free diet. Furthermore, microbial populations in the firebrat's gut decreased significantly over time, even in firebrats feeding on the antibiotic-free diet, without corresponding decreases in gut cellulase levels. Based on this evidence, we conclude that the gut cellulases of firebrats are of insect origin. This conclusion implies that symbiont-independent cellulose digestion is a primitive trait in insects and that symbiont-mediated cellulose digestion is a derived condition.

  9. Estimating Population Turnover Rates by Relative Quantification Methods Reveals Microbial Dynamics in Marine Sediment.

    Science.gov (United States)

    Kevorkian, Richard; Bird, Jordan T; Shumaker, Alexander; Lloyd, Karen G

    2018-01-01

    The difficulty involved in quantifying biogeochemically significant microbes in marine sediments limits our ability to assess interspecific interactions, population turnover times, and niches of uncultured taxa. We incubated surface sediments from Cape Lookout Bight, North Carolina, USA, anoxically at 21°C for 122 days. Sulfate decreased until day 68, after which methane increased, with hydrogen concentrations consistent with the predicted values of an electron donor exerting thermodynamic control. We measured turnover times using two relative quantification methods, quantitative PCR (qPCR) and the product of 16S gene read abundance and total cell abundance (FRAxC, which stands for "fraction of read abundance times cells"), to estimate the population turnover rates of uncultured clades. Most 16S rRNA reads were from deeply branching uncultured groups, and ∼98% of 16S rRNA genes did not abruptly shift in relative abundance when sulfate reduction gave way to methanogenesis. Uncultured Methanomicrobiales and Methanosarcinales increased at the onset of methanogenesis with population turnover times estimated from qPCR at 9.7 ± 3.9 and 12.6 ± 4.1 days, respectively. These were consistent with FRAxC turnover times of 9.4 ± 5.8 and 9.2 ± 3.5 days, respectively. Uncultured Syntrophaceae , which are possibly fermentative syntrophs of methanogens, and uncultured Kazan-3A-21 archaea also increased at the onset of methanogenesis, with FRAxC turnover times of 14.7 ± 6.9 and 10.6 ± 3.6 days. Kazan-3A-21 may therefore either perform methanogenesis or form a fermentative syntrophy with methanogens. Three genera of sulfate-reducing bacteria, Desulfovibrio , Desulfobacter , and Desulfobacterium , increased in the first 19 days before declining rapidly during sulfate reduction. We conclude that population turnover times on the order of days can be measured robustly in organic-rich marine sediment, and the transition from sulfate-reducing to methanogenic conditions stimulates

  10. Microbial population analysis improves the evidential value of faecal traces in forensic investigations.

    Science.gov (United States)

    Quaak, Frederike C A; de Graaf, Mei-Lan M; Weterings, Rob; Kuiper, Irene

    2017-01-01

    The forensic science community has a growing interest in microbial population analysis, especially the microbial populations found inside and on the human body. Both their high abundance, microbes outnumber human cells by a factor 10, and their diversity, different sites of the human body harbour different microbial communities, make them an interesting tool for forensics. Faecal material is a type of trace evidence which can be found in a variety of criminal cases, but is often being ignored in forensic investigations. Deriving a human short tandem repeat (STR) profile from a faecal sample can be challenging. However, the microbial communities within faecal material can be of additional criminalistic value in linking a faecal trace to the possible donor. We present a microarray technique in which the faecal microbial community is used to differentiate between faecal samples and developed a decision model to predict the possible common origin of questioned samples. The results show that this technique may be a useful additional tool when no or only partial human STR profiles can be generated.

  11. Microbial populations causing off-flavour in recirculated aquaculture systems

    DEFF Research Database (Denmark)

    Lukassen, Mie Bech; Schramm, Edward; Nielsen, Jeppe Lund

    the distribution of geoA in more than 50 European and Brazilian aquaculture systems has allowed us to identify the diversity among geosmin-producing bacteria. The different populations of geosmin-producers were evaluated relative to plant design, environmental and operational parameters in full-scale aquaculture...... systems using multivariate statistics. The influencing parameters identified were subsequently validated by testing their gene expressions in well-controlled pilot scale aquaculture systems. The results show that the geoA gene is a relative well-conserved gene with limited horizontal gene transfer events...... phase. Furthermore, the gene expressions of the individual groups show positive correlations to the organic loading and presence of oxygen. The current study reveals the presence of important populations involved in geosmin production and which parameters are of importance for their presence...

  12. Cutaneous Microbial Community Variation across Populations of Eastern Hellbenders (Cryptobranchus alleganiensis alleganiensis

    Directory of Open Access Journals (Sweden)

    Obed Hernández-Gómez

    2017-07-01

    Full Text Available Multicellular hosts maintain complex associations with microbial communities. While microbial communities often serve important functional roles for their hosts, our understanding of the local and regional processes that structure these communities remains limited. Metacommunity analyses provide a promising tool for investigating mechanisms shaping microbiome heterogeneity, which is essential for predicting functional variation between hosts. Using a metacommunity framework, we examined heterogeneity in the skin microbiome of the eastern hellbender (Cryptobranchus alleganiensis alleganiensis. Hellbenders are broadly distributed throughout river systems in the eastern United States, but are present in specific environmental locations throughout their range. The large range of the species and history of population fragmentation suggest that local and regional processes contribute to the distribution of cutaneous symbiont diversity. Therefore, we characterized the skin and environmental bacterial communities at eight rivers throughout the range of the species. We observed variation among hellbender populations in skin microbial community diversity and proportion of shared operational taxonomic units (OTUs between animal and river water communities. Among populations sampled, we noted significant clumped OTU turnover (i.e., Clementsian structure resulting in unique cutaneous communities. In addition, we observed a significant positive correlation between skin community divergence and hellbender population genetic divergence. Host-population skin community dissimilarity did not correlate strongly with distance between sampling locations, indicating a weak spatial effect on the distribution of symbionts. These results suggest that species sorting mechanisms (i.e., local processes structure local skin microbial communities in hellbenders. The variation in skin community composition observed among host populations foreshadows a similar pattern in

  13. Phosphatase Activity of Microbial Populations in Different Milk Samples in Relation to Protein and Carbohydrate Content

    Directory of Open Access Journals (Sweden)

    Sosanka Protim SANDILYA

    2014-12-01

    Full Text Available Cattle milk is a rich source of protein, carbohydrate, vitamins, minerals and all other major and micro nutrients. At a moderate pH, milk is an excellent media for the growth of microbes and thus, intake of raw milk is precarious. In this study, attempt was made for a qualitative study of eight raw milk samples of different varieties of cow and goat milk, collected from Jorhat district of Assam, India, on the basis of nutritional value and microbial population. The highest microbial population was found in the milk collected from cross hybrid variety of cow, whereas microbial contamination was the least in Jersey cow milk. Samples of C1 (Jersey cow variety showed presence of the highest amount of protein and carbohydrate content as compared to the others. Almost all the milk samples showed positive acid and alkaline phosphatase activity. Maximum acid phosphatase activity was observed in cross hybrid cow milk, whereas local cow milk exhibited the highest alkaline phosphatase activity. Phosphatase activity did not show any co-relationship with microbial population of the milk samples. Similarly, the protein and carbohydrate content of the samples did not have any significant impact on both acid and alkaline phosphatase activity.

  14. Use of and microbial resistance to antibiotics in China: a path to reducing antimicrobial resistance.

    Science.gov (United States)

    Cui, Dan; Liu, Xinliang; Hawkey, Peter; Li, Hao; Wang, Quan; Mao, Zongfu; Sun, Jing

    2017-12-01

    We analyzed China's current use of and microbial resistance to antibiotics, and possible means of reducing antimicrobial resistance. Interventions like executive orders within clinical settings and educational approach with vertical approaches rather than an integrated strategy to curb the use of antimicrobials remain limited. An underlying problem is the system of incentives that has resulted in the intensification of inappropriate use by health professionals and patients. There is an urgent need to explore the relationship between financial and non-financial incentives for providers and patients, to eliminate inappropriate incentives. China's national health reforms have created an opportunity to contain inappropriate use of antibiotics through more comprehensive and integrated strategies. Containment of microbial resistance may be achieved by strengthening surveillance at national, regional and hospital levels; eliminating detrimental incentives within the health system; and changing prescribing behaviors to a wider health systems approach, to achieve long-term, equitable and sustainable results and coordinate stakeholders' actions through transparent sharing of information.

  15. Dehydrochlorination of 1,1,1-trichloroethane and pentachloroethane by microbially reduced ferruginous smectite.

    Science.gov (United States)

    Cervini-Silva, Javiera; Kostka, Joel E; Larson, Richard A; Stucki, Joseph W; Wu, Jun

    2003-05-01

    Reduction of structural Fe(III) in smectite clay minerals has been identified as a means to promote dechlorination of polychlorinated ethanes, but its environmental significance has yet to be fully assessed because Fe reduction has normally been achieved by agents uncommon in the environment (e.g., dithionite). This study reports the dehydrochlorination of pentachloroethane and 1,1,1-trichloroethane in the presence of ferruginous smectite reduced by two cultures of microorganisms, Shewanella oneidensis strain MR-1 (MR-R) and an enrichment culture from rice paddy soils (PS-R), in aqueous suspension under anoxic conditions. Microbially reduced ferruginous smectite facilitated dehydrochlorination of 1,1,1-trichloroethane to 1,1-dichloroethene with up to 60% conversion within 3 h of incubation time. In contrast, no formation of 1,1-dichloroethene was observed after incubation of 1,1,1-trichloroethane with chemically reduced ferruginous smectite for 24 h. Microbially reduced ferruginous smectite by MR-R and PS-R promoted the dehydrochlorination of pentachloroethane to tetrachloroethene by 80 and 15%, respectively, after 3 h of incubation time. The conversion of pentachloroethane to tetrachloroethene in the presence of chemically reduced ferruginous smectite after 24 h was 65%. These results indicate that structural Fe(II) in clay minerals has the potential to be an important reductant controlling the fate of organic chemicals in contaminated sediments.

  16. Long-term application of winery wastewater - Effect on soil microbial populations and soil chemistry

    Science.gov (United States)

    Mosse, Kim; Patti, Antonio; Smernik, Ron; Cavagnaro, Timothy

    2010-05-01

    The ability to reuse winery wastewater (WWW) has potential benefits both with respect to treatment of a waste stream, as well as providing a beneficial water resource in water limited regions such as south-eastern Australia, California and South Africa. Over an extended time period, this practice leads to changes in soil chemistry, and potentially, also to soil microbial populations. In this study, we compared the short term effects of WWW (both treated and untreated) application on soil biology and chemistry in two adjacent paired sites with the same soil type, one of which had received WWW for approximately 30 years, and the other which had not. The paired sites were treated with an industrially relevant quantity of WWW, and the soil microbial activity (measured as soil CO2 efflux) and common soil physicochemical properties were monitored over a 16-day period. In addition, Solid State 13C NMR was employed on whole soil samples from the two sites, to measure and compare the chemical nature of the soil organic matter at the paired sites. The acclimatised soil showed a high level of organic matter and a greater spike in microbial activity following WWW addition, in comparison with the non-acclimatised soil, suggesting differences in soil chemistry and soil microbial communities between the two sites. Soil nitrate and phosphorus levels showed significant differences between WWW treatments; these differences likely to be microbially mediated.

  17. Methodological flaws introduce strong bias into molecular analysis of microbial populations.

    Science.gov (United States)

    Krakat, N; Anjum, R; Demirel, B; Schröder, P

    2017-02-01

    In this study, we report how different cell disruption methods, PCR primers and in silico analyses can seriously bias results from microbial population studies, with consequences for the credibility and reproducibility of the findings. Our results emphasize the pitfalls of commonly used experimental methods that can seriously weaken the interpretation of results. Four different cell lysis methods, three commonly used primer pairs and various computer-based analyses were applied to investigate the microbial diversity of a fermentation sample composed of chicken dung. The fault-prone, but still frequently used, amplified rRNA gene restriction analysis was chosen to identify common weaknesses. In contrast to other studies, we focused on the complete analytical process, from cell disruption to in silico analysis, and identified potential error rates. This identified a wide disagreement of results between applied experimental approaches leading to very different community structures depending on the chosen approach. The interpretation of microbial diversity data remains a challenge. In order to accurately investigate the taxonomic diversity and structure of prokaryotic communities, we suggest a multi-level approach combining DNA-based and DNA-independent techniques. The identified weaknesses of commonly used methods to study microbial diversity can be overcome by a multi-level approach, which produces more reliable data about the fate and behaviour of microbial communities of engineered habitats such as biogas plants, so that the best performance can be ensured. © 2016 The Society for Applied Microbiology.

  18. Meta-Transcriptomic Analysis of a Chromate-Reducing Aquifer Microbial Community

    Science.gov (United States)

    Beller, H. R.; Brodie, E. L.; Han, R.; Karaoz, U.

    2010-12-01

    A major challenge for microbial ecology that has become more tractable in the advent of new molecular techniques is characterizing gene expression in complex microbial communities. We are using meta-transcriptomic analysis to characterize functional changes in an aquifer-derived, chromate-reducing microbial community as it transitions through various electron-accepting conditions. We inoculated anaerobic microcosms with groundwater from the Cr-contaminated Hanford 100H site and supplemented them with lactate and electron acceptors present at the site, namely, nitrate, sulfate, and Fe(III). The microcosms progressed successively through various electron-accepting conditions (e.g., denitrifying, sulfate-reducing, and ferric iron-reducing conditions, as well as nitrate-dependent, chemolithotrophic Fe(II)-oxidizing conditions). Cr(VI) was rapidly reduced initially and again upon further Cr(VI) amendments. Extensive geochemical sampling and analysis (e.g., lactate, acetate, chloride, nitrate, nitrite, sulfate, dissolved Cr(VI), total Fe(II)), RNA/DNA harvesting, and PhyloChip analyses were conducted. Methods were developed for removal of rRNA from total RNA in preparation for meta-transcriptome sequencing. To date, samples representing denitrifying and fermentative/sulfate-reducing conditions have been sequenced using 454 Titanium technology. Of the non-rRNA related reads for the denitrifying sample (which was also actively reducing chromate), ca. 8% were associated with denitrification and ca. 0.9% were associated with chromate resistance/transport, in contrast to the fermentative/sulfate-reducing sample (in which chromate had already been reduced), which had zero reads associated with either of these categories but many predicted proteins associated with sulfate-reducing bacteria. We observed sequences for key functional transcripts that were unique at the nucleotide level compared to the GenBank non-redundant database [such as L-lactate dehydrogenase (iron

  19. Milankovitch-scale correlations between deeply buried microbial populations and biogenic ooze lithology

    Science.gov (United States)

    Aiello, I.W.; Bekins, B.A.

    2010-01-01

    The recent discoveries of large, active populations of microbes in the subseafloor of the world's oceans supports the impact of the deep biosphere biota on global biogeochemical cycles and raises important questions concerning the functioning of these extreme environments for life. These investigations demonstrated that subseafloor microbes are unevenly distributed and that cell abundances and metabolic activities are often independent from sediment depths, with increased prokaryotic activity at geochemical and/or sedimentary interfaces. In this study we demonstrate that microbial populations vary at the scale of individual beds in the biogenic oozes of a drill site in the eastern equatorial Pacific (Ocean Drilling Program Leg 201, Site 1226). We relate bedding-scale changes in biogenic ooze sediment composition to organic carbon (OC) and microbial cell concentrations using high-resolution color reflectance data as proxy for lithology. Our analyses demonstrate that microbial concentrations are an order of magnitude higher in the more organic-rich diatom oozes than in the nannofossil oozes. The variations mimic small-scale variations in diatom abundance and OC, indicating that the modern distribution of microbial biomass is ultimately controlled by Milankovitch-frequency variations in past oceanographic conditions. ?? 2010 Geological Society of America.

  20. Strategies for Reducing the Start-up Operation of Microbial Electrochemical Treatments of Urban Wastewater

    Directory of Open Access Journals (Sweden)

    Zulema Borjas

    2015-12-01

    Full Text Available Microbial electrochemical technologies (METs constitute the core of a number of emerging technologies with a high potential for treating urban wastewater due to a fascinating reaction mechanism—the electron transfer between bacteria and electrodes to transform metabolism into electrical current. In the current work, we focus on the model electroactive microorganism Geobacter sulfurreducens to explore both the design of new start-up procedures and electrochemical operations. Our chemostat-grown plug and play cells, were able to reduce the start-up period by 20-fold while enhancing chemical oxygen demand (COD removal by more than 6-fold during this period. Moreover, a filter-press based bioreactor was successfully tested for both acetate-supplemented synthetic wastewater and real urban wastewater. This proof-of-concept pre-pilot treatment included a microbial electrolysis cell (MEC followed in time by a microbial fuel cell (MFC to finally generate electrical current of ca. 20 A·m−2 with a power of 10 W·m−2 while removing 42 g COD day−1·m−2. The effective removal of acetate suggests a potential use of this modular technology for treating acetogenic wastewater where Geobacter sulfurreducens outcompetes other organisms.

  1. Microbial deposition of gold nanoparticles by the metal-reducing bacterium Shewanella algae

    International Nuclear Information System (INIS)

    Konishi, Y.; Tsukiyama, T.; Tachimi, T.; Saitoh, N.; Nomura, T.; Nagamine, S.

    2007-01-01

    Microbial reduction and deposition of gold nanoparticles was achieved at 25 deg. C over the pH range 2.0-7.0 using the mesophilic bacterium Shewanella algae in the presence of H 2 as the electron donor. The reductive deposition of gold by the resting cells of S. algae was a fast process: 1 mM AuCl 4 - ions were completely reduced to elemental gold within 30 min. At a solution pH of 7, gold nanoparticles 10-20 nm in size were deposited in the periplasmic space of S. algae cells. At pH 2.8, gold nanoparticles 15-200 nm in size were deposited on the bacterial cells, and the biogenic nanoparticles exhibited a variety of shapes that included nanotriangles: in particular, single crystalline gold nanotriangles 100-200 nm in size were microbially deposited. At a solution pH of 2.0, gold nanoparticles about 20 nm in size were deposited intracellularly, and larger gold particles approximately 350 nm in size were deposited extracellularly. The solution pH was an important factor in controlling the morphology of the biogenic gold particles and the location of gold deposition. Microbial deposition of gold nanoparticles is potentially attractive as an environmentally friendly alternative to conventional methods

  2. Effects of extracts on ruminal fermentation characteristics, methanogenesis, and microbial populations

    Directory of Open Access Journals (Sweden)

    Shin Ja Lee

    2018-01-01

    Full Text Available Objective Gelidium amansii (Lamouroux is a red alga belonging to the family Gelidaceae and is commonly found in the shallow coasts of many East Asian countries, including Korea, China, and Japan. G. amansii has traditionally been utilized as an edible alga, and has various biological activities. The objective of this study was to determine whether dietary supplementation of G. amansii could be useful for improving ruminal fermentation. Methods As assessed by in vitro fermentation parameters such as pH, total gas, volatile fatty acid (VFA production, gas profile (methane, carbon dioxide, hydrogen, and ammonia, and microbial growth rate was compared to a basal diet with timothy hay. Cannulated Holstein cows were used as rumen fluid donors and 15 mL rumen fluid: buffer (1:2 was incubated for up to 72 h with four treatments with three replicates. The treatments were: control (timothy only, basal diet with 1% G. amansii extract, basal diet with 3% G. amansii extract, and basal diet with 5% G. amansii extract. Results Overall, the results of our study indicate that G. amansii supplementation is potentially useful for improving ruminant growth performance, via increased total gas and VFA production, but does come with some undesirable effects, such as increasing pH, ammonia concentration, and methane production. In particular, real-time polymerase chain reaction indicated that the methanogenic archaea and Fibrobacter succinogenes populations were significantly reduced, while the Ruminococcus flavefaciens populations were significantly increased at 24 h, when supplemented with G. amansii extracts as compared with controls. Conclusion More research is required to elucidate what G. amansii supplementation can do to improve growth performance, and its effect on methane production in ruminants.

  3. Effects of Gelidium amansii extracts on in vitro ruminal fermentation characteristics, methanogenesis, and microbial populations.

    Science.gov (United States)

    Lee, Shin Ja; Shin, Nyeon Hak; Jeong, Jin Suk; Kim, Eun Tae; Lee, Su Kyoung; Lee, Il Dong; Lee, Sung Sill

    2018-01-01

    Gelidium amansii (Lamouroux) is a red alga belonging to the family Gelidaceae and is commonly found in the shallow coasts of many East Asian countries, including Korea, China, and Japan. G. amansii has traditionally been utilized as an edible alga, and has various biological activities. The objective of this study was to determine whether dietary supplementation of G. amansii could be useful for improving ruminal fermentation. As assessed by in vitro fermentation parameters such as pH, total gas, volatile fatty acid (VFA) production, gas profile (methane, carbon dioxide, hydrogen, and ammonia), and microbial growth rate was compared to a basal diet with timothy hay. Cannulated Holstein cows were used as rumen fluid donors and 15 mL rumen fluid: buffer (1:2) was incubated for up to 72 h with four treatments with three replicates. The treatments were: control (timothy only), basal diet with 1% G. amansii extract, basal diet with 3% G. amansii extract, and basal diet with 5% G. amansii extract. Overall, the results of our study indicate that G. amansii supplementation is potentially useful for improving ruminant growth performance, via increased total gas and VFA production, but does come with some undesirable effects, such as increasing pH, ammonia concentration, and methane production. In particular, real-time polymerase chain reaction indicated that the methanogenic archaea and Fibrobacter succinogenes populations were significantly reduced, while the Ruminococcus flavefaciens populations were significantly increased at 24 h, when supplemented with G. amansii extracts as compared with controls. More research is required to elucidate what G. amansii supplementation can do to improve growth performance, and its effect on methane production in ruminants.

  4. Effects of intermittent and continuous aeration on accelerative stabilization and microbial population dynamics in landfill bioreactors.

    Science.gov (United States)

    Sang, Nguyen Nhu; Soda, Satoshi; Inoue, Daisuke; Sei, Kazunari; Ike, Michihiko

    2009-10-01

    Performance and microbial population dynamics in landfill bioreactors were investigated in laboratory experiments. Three reactors were operated without aeration (control reactor, CR), with cyclic 6-h aeration and 6-h non-aeration (intermittently aerated reactor, IAR), and with continuous aeration (continuously aerated reactor, CAR). Each reactor was loaded with high-organic solid waste. The performance of IAR was highest among the reactors up to day 90. The respective solid weight, organic matter content, and waste volume on day 90 in the CR, IAR, and CAR were 50.9, 39.1, and 47.5%; 46.5, 29.3 and 35.0%; and 69, 38, and 53% of the initial values. Organic carbon and nitrogen compounds in leachate in the IAR and the CAR showed significant decreases in comparison to those in the CR. The most probable number (MPN) values of fungal 18S rDNA in the CAR and the IAR were higher than those in the CR. Terminal restriction fragment length polymorphism analysis showed that unique and diverse eubacterial and archaeal communities were formed in the IAR. The intermittent aeration strategy was favorable for initiation of solubilization of organic matter by the aerobic fungal populations and the reduction of the acid formation phase. Then the anaerobic H(2)-producing bacteria Clostridium became dominant in the IAR. Sulfate-reducing bacteria, which cannot use acetate/sulfate but which instead use various organics/sulfate as the electron donor/acceptor were also dominant in the IAR. Consequently, Methanosarcinales, which are acetate-utilizing methanogens, became the dominant archaea in the IAR, where high methane production was observed.

  5. Effects of Flavonoid-rich Plant Extracts on Ruminal Methanogenesis, Microbial Populations and Fermentation Characteristics

    Directory of Open Access Journals (Sweden)

    Eun T. Kim

    2015-04-01

    Full Text Available The objective of this study was to evaluate the in vitro effects of flavonoid-rich plant extracts (PE on ruminal fermentation characteristics and methane emission by studying their effectiveness for methanogenesis in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The PE (Punica granatum, Betula schmidtii, Ginkgo biloba, Camellia japonica, and Cudrania tricuspidata known to have high concentrations of flavonoid were added to an in vitro fermentation incubated with rumen fluid. Total gas production and microbial growth with all PE was higher than that of the control at 24 h incubation, while the methane emission was significantly lower (p<0.05 than that of the control. The decrease in methane accumulation relative to the control was 47.6%, 39.6%, 46.7%, 47.9%, and 48.8% for Punica, Betula, Ginkgo, Camellia, and Cudrania treatments, respectively. Ciliate populations were reduced by more than 60% in flavonoid-rich PE treatments. The Fibrobacter succinogenes diversity in all added flavonoid-rich PE was shown to increase, while the Ruminoccocus albus and R. flavefaciens populations in all PE decreased as compared with the control. In particular, the F. succinogenes community with the addition of Birch extract increased to a greater extent than that of others. In conclusion, the results of this study showed that flavonoid-rich PE decreased ruminal methane emission without adversely affecting ruminal fermentation characteristics in vitro in 24 h incubation time, suggesting that the flavonoid-rich PE have potential possibility as bio-active regulator for ruminants.

  6. Experimental evolution and the dynamics of adaptation and genome evolution in microbial populations.

    Science.gov (United States)

    Lenski, Richard E

    2017-10-01

    Evolution is an on-going process, and it can be studied experimentally in organisms with rapid generations. My team has maintained 12 populations of Escherichia coli in a simple laboratory environment for >25 years and 60 000 generations. We have quantified the dynamics of adaptation by natural selection, seen some of the populations diverge into stably coexisting ecotypes, described changes in the bacteria's mutation rate, observed the new ability to exploit a previously untapped carbon source, characterized the dynamics of genome evolution and used parallel evolution to identify the genetic targets of selection. I discuss what the future might hold for this particular experiment, briefly highlight some other microbial evolution experiments and suggest how the fields of experimental evolution and microbial ecology might intersect going forward.

  7. Monomethylhydrazine degradation and its effect on carbon dioxide evolution and microbial populations in soil

    International Nuclear Information System (INIS)

    Ou, L.T.; Street, J.J.

    1988-01-01

    Monomethylhydrazine (MMH), along with hydrazine and 1,1-dimethylhydrazine are the main components of hydrazine fuels. Information on the fate of MMH in soil and its overall effect on soil microbial activity is not known, though MMH is known to be toxic to a number of soil bacteria. Despite the fact that axenic bacterial cultures are inhibited by the three hydrazines, Ou and Street reported that soil respiration, and total bacterial and fungal populations in soil, were not inhibited by hydrazine at concentrations of 100 μg/g and lower. Even at 500 μg/g, only total bacterial populations in soil were inhibited by the presence of hydrazine. They also reported that hydrazine rapidly disappeared in soil. The authors initiated this study to investigate the effect of MMH on soil microbial activity and on degradation of the chemical in soil

  8. Dynamics of organic matter and microbial populations in amended soil: a multidisciplinary approach

    Science.gov (United States)

    Gigliotti, Giovanni; Pezzolla, Daniela; Zadra, Claudia; Albertini, Emidio; Marconi, Gianpiero; Turchetti, Benedetta; Buzzini, Pietro

    2013-04-01

    The application of organic amendments to soils, such as pig slurry, sewage sludge and compost is considered a tool for improving soil fertility and enhancing C stock. The addition of these different organic materials allows a good supply of nutrients for plants but also contributes to C sequestration, affects the microbial activity and the transformation of soil organic matter (SOM). Moreover, the addition of organic amendment has gained importance as a source of greenhouse gas (GHG) emissions and then as a cause of the "Global Warming". Therefore, it is important to investigate the factors controlling the SOM mineralization in order to improve soil C sequestration and decreasing at the same time the GHG emissions. The quality of organic matter added to the soil will play an important role in these dynamics, affecting the microbial activity and the changes in microbial community structure. A laboratory, multidisciplinary experiment was carried out to test the effect of the amendment by anaerobic digested livestock-derived organic materials on labile organic matter evolution and on dynamics of microbial population, this latter both in terms of consistence of microbial biomass, as well as in terms of microbial biodiversity. Different approaches were used to study the microbial community structure: chemical (CO2 fluxes, WEOC, C-biomass, PLFA), microbiological (microbial enumeration) and molecular (DNA extraction and Roche 454, Next Generation Sequencing, NGS). The application of fresh digestate, derived from the anaerobic treatment of animal wastes, affected the short-term dynamics of microbial community, as reflected by the increase of CO2 emissions immediately after the amendment compared to the control soil. This is probably due to the addition of easily available C added with the digestate, demonstrating that this organic material was only partially stabilized by the anaerobic process. In fact, the digestate contained a high amounts of available C, which led to

  9. Effects of feeding whole linseed on ruminal fatty acid composition and microbial population in goats

    Directory of Open Access Journals (Sweden)

    Kamaleldin Abuelfatah

    2016-12-01

    Full Text Available The objective of the present study was to evaluate the effect of feeding different levels of whole linseed, as a source of n-3 polyunsaturated fatty acids (PUFA, on ruminal fatty acid composition and microbial population in the goat. Twenty-four crossbred Boer goats were assigned to 3 dietary treatments: L0 (control, L10 and L20 containing 0, 10%, or 20% whole linseed, respectively. The ruminal pH and concentration of total volatile fatty acids (VFA were not affected by dietary treatments. The feeding of L10 and L20 diets produced higher (P < 0.05 molar proportions of acetate and lower (P < 0.05 molar proportions of butyrate and valerate than the L0 diet. Molar proportions of myristic acid (C14:0 and palmitic acid (C16:0 were lower (P < 0.05 in the rumen of goats offered L10 and L20 diets than the control diet. However, stearic acid (C18:0, vaccenic acid (C18:1 trans-11, conjugated linoleic acid (CLA, C18:2 trans-10, cis-12 and α-lenolenic acid (C18:3 n-3 were higher (P < 0.05 in the rumen of goats fed L10 and L20 than L0. Both inclusion levels of linseed in the diet (L10 and L20 reduced the ruminal total bacteria, methanogens, and protozoa compared with L0 (P < 0.05. The effect of the dietary treatments on cellulolytic bacteria, varied between the individual species. Both inclusion levels of linseed resulted in a significant decrease (P < 0.05 in the population of Fibrobacter succinogenes, and Rumunococus flavefaciens compared with L0, with no significant difference between the groups fed linseed diets. The population of Rumunococus albus was not affected by the different dietary treatments. It was concluded that inclusion of whole linseed in the diet of goats could increase the concentration of PUFA in the rumen, and decrease the population of F. succinogenes, R. flavefaciens, methanogens and protozoa in rumen liquid of goats.

  10. Increasing atmospheric deposition nitrogen and ammonium reduced microbial activity and changed the bacterial community composition of red paddy soil.

    Science.gov (United States)

    Zhou, Fengwu; Cui, Jian; Zhou, Jing; Yang, John; Li, Yong; Leng, Qiangmei; Wang, Yangqing; He, Dongyi; Song, Liyan; Gao, Min; Zeng, Jun; Chan, Andy

    2018-03-27

    Atmospheric deposition nitrogen (ADN) increases the N content in soil and subsequently impacts microbial activity of soil. However, the effects of ADN on paddy soil microbial activity have not been well characterized. In this study, we studied how red paddy soil microbial activity responses to different contents of ADN through a 10-months ADN simulation on well managed pot experiments. Results showed that all tested contents of ADN fluxes (27, 55, and 82kgNha -1 when its ratio of NH 4 + /NO 3 - -N (R N ) was 2:1) enhanced the soil enzyme activity and microbial biomass carbon and nitrogen and 27kgNha -1 ADN had maximum effects while comparing with the fertilizer treatment. Generally, increasing of both ADN flux and R N (1:2, 1:1 and 2:1 with the ADN flux of 55kgNha -1 ) had similar reduced effects on microbial activity. Furthermore, both ADN flux and R N significantly reduced soil bacterial alpha diversity (pADN flux and R N were the main drivers in shaping paddy soil bacteria community. Overall, the results have indicated that increasing ADN flux and ammonium reduced soil microbial activity and changed the soil bacterial community. The finding highlights how paddy soil microbial community response to ADN and provides information for N management in paddy soil. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Sequential enrichment of microbial population exhibiting enhanced biodegradation of crude oil

    International Nuclear Information System (INIS)

    Venkateswaran, Kasthuri; Harayama, Shigeaki.

    1995-01-01

    The distribution of oil-degrading bacteria in the coastal waters and sediments of Hokkaido, Japan, was surveyed. It was found that the potential of mixed microbial populations to degrade weathered crude oil was not confined to any ecological components (water or sediment) nor to the sampling stations. One microbial culture that was stable during repeated subculturing degraded 45% of the saturates and 20% of the aromatics present in crude oil in 10 days during the initial screening. The residual hydrocarbons in this culture were extracted by chloroform and dispersed in a fresh seawater-based medium and subsequently inoculated with microorganisms from the first culture. After full growth of the second culture, the residual hydrocarbons were extracted and dispersed in a fresh medium in which microorganisms from the second culture had been inoculated. This sequential process was carried out six times to enrich those microorganisms that grew on the recalcitrant components of crude oil. After repeated exposure of the residual crude oil to the enriched microorganisms, about 80% of the initially added crude oil was degraded. The cultures obtained after each enrichment cycle were kept, and the degradation of fresh crude oil by the enriched microorganisms was monitored. The degrading activity of the enriched cultures increased as the number of enrichment cycles increased. A microbial population that had been selected six times on the residual crude oil could degrade 70% of the saturates and 30% of the aromatics of crude oil, indicating that growth of a microbial population on residual crude oil improved its ability to biodegrade crude oil. 21 refs., 2 tabs., 7 figs

  12. Bioremediation of hydrocarbon degradation in a petroleum-contaminated soil and microbial population and activity determination.

    Science.gov (United States)

    Wu, Manli; Li, Wei; Dick, Warren A; Ye, Xiqiong; Chen, Kaili; Kost, David; Chen, Liming

    2017-02-01

    Bioremediation of hydrocarbon degradation in petroleum-polluted soil is carried out by various microorganisms. However, little information is available for the relationships between hydrocarbon degradation rates in petroleum-contaminated soil and microbial population and activity in laboratory assay. In a microcosm study, degradation rate and efficiency of total petroleum hydrocarbons (TPH), alkanes, and polycyclic aromatic hydrocarbons (PAH) in a petroleum-contaminated soil were determined using an infrared photometer oil content analyzer and a gas chromatography mass spectrometry (GC-MS). Also, the populations of TPH, alkane, and PAH degraders were enumerated by a modified most probable number (MPN) procedure, and the hydrocarbon degrading activities of these degraders were determined by the Biolog (MT2) MicroPlates assay. Results showed linear correlations between the TPH and alkane degradation rates and the population and activity increases of TPH and alkane degraders, but no correlation was observed between the PAH degradation rates and the PAH population and activity increases. Petroleum hydrocarbon degrading microbial population measured by MPN was significantly correlated with metabolic activity in the Biolog assay. The results suggest that the MPN procedure and the Biolog assay are efficient methods for assessing the rates of TPH and alkane, but not PAH, bioremediation in oil-contaminated soil in laboratory. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Effects of Plant Extracts on Microbial Population, Methane Emission and Ruminal Fermentation Characteristics in

    Directory of Open Access Journals (Sweden)

    E. T. Kim

    2012-06-01

    Full Text Available This study was conducted to evaluate effects of plant extracts on methanogenesis and rumen microbial diversity in in vitro. Plant extracts (Artemisia princeps var. Orientalis; Wormwood, Allium sativum for. Pekinense; Garlic, Allium cepa; Onion, Zingiber officinale; Ginger, Citrus unshiu; Mandarin orange, Lonicera japonica; Honeysuckle were obtained from the Plant Extract Bank at Korea Research Institute of Bioscience and Biotechnology. The rumen fluid was collected before morning feeding from a fistulated Holstein cow fed timothy and commercial concentrate (TDN; 73.5%, crude protein; 19%, crude fat; 3%, crude fiber; 12%, crude ash; 10%, Ca; 0.8%, P; 1.2% in the ratio of 3 to 2. The 30 ml of mixture, comprising McDougall buffer and rumen liquor in the ratio of 4 to 1, was dispensed anaerobically into serum bottles containing 0.3 g of timothy substrate and plant extracts (1% of total volume, respectively filled with O2-free N2 gas and capped with a rubber stopper. The serum bottles were held in a shaking incubator at 39°C for 24 h. Total gas production in all plant extracts was higher (p<0.05 than that of the control, and total gas production of ginger extract was highest (p<0.05. The methane emission was highest (p<0.05 at control, but lowest (p<0.05 at garlic extract which was reduced to about 20% of methane emission (40.2 vs 32.5 ml/g DM. Other plant extracts also resulted in a decrease in methane emissions (wormwood; 8%, onion; 16%, ginger; 16.7%, mandarin orange; 12%, honeysuckle; 12.2%. Total VFAs concentration and pH were not influenced by the addition of plant extracts. Acetate to propionate ratios from garlic and ginger extracts addition samples were lower (p<0.05, 3.36 and 3.38 vs 3.53 than that of the control. Real-time PCR indicted that the ciliate-associated methanogen population in all added plant extracts decreased more than that of the control, while the fibrolytic bacteria population increased. In particular, the F. succinogens

  14. Evaluation of Sanitizing Methods for Reducing Microbial Contamination on Fresh Strawberry, Cherry Tomato, and Red Bayberry

    Directory of Open Access Journals (Sweden)

    Wei Wei

    2017-12-01

    Full Text Available Strawberries, cherry tomatoes, and red bayberries, which are the most popular types of fresh produce in China, are vulnerable to microbial contamination. In this study, different sanitizing methods [treatment with 2% organic acids, 0.02% sodium hypochlorite (SH, 0.1% sodium chlorite (SC, and 0.1% acidified sodium chlorite (ASC] were applied to fresh strawberry, cherry tomato, and red bayberry, and their abilities to reduce aerobic bacteria, Escherichia coli O157:H7, mold, yeast, and Salmonella Typhimurium were evaluated. The commercially used SH method reduced the background microbiota on strawberry, cherry tomato, and red bayberry by 0.20–2.07 log cfu/g. The ASC method reduced background microbiota (except for mold on strawberry and cherry tomato by more than 3.0 log cfu/g. ASC was the only sanitizer that significantly reduced mold on red bayberry, and lactic acid was the only organic acid sanitizer that effectively reduced yeast on red bayberry. The ASC method had the best sterilizing effect on the three fresh fruits and also required the shortest sanitizing time and low chlorite content. The application of ASC method significantly reduced the microbiota on retail grocery samples, and the effect was similar to that achieved by sanitizing methods comparison.

  15. In situ Microbial Community Control of the Stability of Bio-Reduced Uranium

    International Nuclear Information System (INIS)

    Long, Phillip E.; McKinley, James P.; White, David C.

    2006-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is soluble and thus mobile compared to U(IV). Previous work at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site demonstrated that biostimulation by acetate injection promoted growth of Geobacteraceae and stimulated the microbial reduction of U(VI) to less soluble U(IV) (1, 4). Despite the potential for oxidative dissolution of bio-reduced U(IV), field experiments at the Old Rifle site show that although the rate of U(VI) reduction decreases following the on-set of sulfate reduction, U(VI) reduction continues even following the cessation of acetate injection (1, 4). However, U(VI) reduction is reversible and the basis for the observed maintenance of U(VI) reduction post-stimulation is a critical but as yet unresolved issue for the application of biostimulation as a treatment technology. The continued U(VI) reduction and the maintenance of reduced U(IV) may result from many factors including U(VI) reduction by sulfate reducing bacteria (SRB), generation of H2S or FeS0.9 which serves as an oxygen sink, or the preferential sorption of U(VI) by microbial cells or biopolymers. The overall goal of the project is to develop an understanding of the mechanisms for the maintenance of bio-reduced uranium in an aerobic aquifer under field conditions following the cessation of electron donor addition

  16. Diets of differentially processed wheat alter ruminal fermentation parameters and microbial populations in beef cattle.

    Science.gov (United States)

    Jiang, S Z; Yang, Z B; Yang, W R; Li, Z; Zhang, C Y; Liu, X M; Wan, F C

    2015-11-01

    The influences of differently processed wheat products on rumen fermentation, microbial populations, and serum biochemistry profiles in beef cattle were studied. Four ruminally cannulated Limousin × Luxi beef cattle (400 ± 10 kg) were used in the experiment with a 4 × 4 Latin square design. The experimental diets contained (on a DM basis) 60% corn silage as a forage source and 40% concentrate with 4 differently processed wheat products (extruded, pulverized, crushed, and rolled wheat). Concentrations of ruminal NH-N and microbial protein (MCP) in cattle fed crushed and rolled wheat were greater ( Ruminal concentrations of total VFA and acetate and the ratio of acetate to propionate decreased ( 0.05). Our findings suggest that the method of wheat processing could have a significant effect on ruminal fermentation parameters and microbial populations in beef cattle and that crushed and rolled processing is better in terms of ruminal NH-N and MCP content, acetate-to-propionate ratio, and relative abundance of rumen microorganisms.

  17. On reducibility and ergodicity of population projection matrix models

    DEFF Research Database (Denmark)

    Stott, Iain; Townley, Stuart; Carslake, David

    2010-01-01

    from all stages to all other stages) and therefore ergodic (whatever initial stage structure is used in the population projection, it will always exhibit the same stable asymptotic growth rate). 2. Evaluation of 652 PPM models for 171 species from the literature suggests that 24·7% of PPM models...... structure used in the population projection). In our sample of published PPMs, 15·6% are non-ergodic. 3. This presents a problem: reducible–ergodic models often defy biological rationale in their description of the life cycle but may or may not prove problematic for analysis as they often behave similarly...... of reducibility in published PPMs, with significant implications for the predictive power of such models in many cases. We suggest that as a general rule, reducibility of PPM models should be avoided. However, we provide a guide to the pertinent analysis of reducible matrix models, largely based upon whether...

  18. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    International Nuclear Information System (INIS)

    Baldwin, Brett R.; Peacock, Aaron D.; Resch, Charles T.; Arntzen, Evan; Smithgall, Amanda N.; Pfiffner, Susan; Gan, M.; McKinley, James P.; Long, Philip E.; White, David C.

    2008-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  19. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

    2008-03-28

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  20. Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats

    Directory of Open Access Journals (Sweden)

    Jackson Z Lee

    2014-02-01

    Full Text Available Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB. However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico -- permanently submerged Microcoleus microbial mats (GN-S, and intertidal Lyngbya microbial mats (GN-I -- were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl-1,1-dimethylurea (DCMU, molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of dsrA phylotypes were responsible for H2 consumption. Incubation with 13C-acetate and nanoSIMS (secondary ion mass-spectrometry indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi.

  1. Variation in microbial population during composting of agro-industrial waste.

    Science.gov (United States)

    Coelho, Luísa; Reis, Mário; Dionísio, Lídia

    2013-05-01

    Two compost piles were prepared, using two ventilation systems: forced ventilation and ventilation through mechanical turning. The material to compost was a mixture of orange waste, olive pomace, and grass clippings (2:1:1 v/v). During the composting period (375 days), samples were periodically taken from both piles, and the enumeration of fungi, actinomycetes, and heterotrophic bacteria was carried out. All studied microorganisms were incubated at 25 and 55 °C after inoculation in appropriate growth media. Fungi were dominant in the early stages of both composting processes; heterotrophic bacteria proliferated mainly during the thermophilic stage, and actinomycetes were more abundant in the final stage of the composting process. Our results showed that the physical and chemical parameters: temperature, pH, moisture, and aeration influenced the variation of the microbial population along the composting process. This study demonstrated that composting of these types of wastes, despite the prolonged mesophilic stage, provided an expected microbial variation.

  2. Microbial contamination and effects of combination treatments and gamma irradiation on reducing microbial contamination of dried cuttle fish

    International Nuclear Information System (INIS)

    Yen, B.T.

    1989-01-01

    Dried cuttle fish is one of the most valuable sea products but it rapidly becomes mouldy and spoiled. To solve this problem, the studies on microbial contamination and effects of combination treatments and gamma irradiation for dried cuttle fish have been caried out base on IAEA Research Contracts No 4397/AG and 4397/R1/AG

  3. Microbial Diversity in Sulfate-Reducing Marine Sediment Enrichment Cultures Associated with Anaerobic Biotransformation of Coastal Stockpiled Phosphogypsum (Sfax, Tunisia

    Directory of Open Access Journals (Sweden)

    Hana Zouch

    2017-08-01

    Full Text Available Anaerobic biotechnology using sulfate-reducing bacteria (SRB is a promising alternative for reducing long-term stockpiling of phosphogypsum (PG, an acidic (pH ~3 by-product of the phosphate fertilizer industries containing high amounts of sulfate. The main objective of this study was to evaluate, for the first time, the diversity and ability of anaerobic marine microorganisms to convert sulfate from PG into sulfide, in order to look for marine SRB of biotechnological interest. A series of sulfate-reducing enrichment cultures were performed using different electron donors (i.e., acetate, formate, or lactate and sulfate sources (i.e., sodium sulfate or PG as electron acceptors. Significant sulfide production was observed from enrichment cultures inoculated with marine sediments, collected near the effluent discharge point of a Tunisian fertilizer industry (Sfax, Tunisia. Sulfate sources impacted sulfide production rates from marine sediments as well as the diversity of SRB species belonging to Deltaproteobacteria. When PG was used as sulfate source, Desulfovibrio species dominated microbial communities of marine sediments, while Desulfobacter species were mainly detected using sodium sulfate. Sulfide production was also affected depending on the electron donor used, with the highest production obtained using formate. In contrast, low sulfide production (acetate-containing cultures was associated with an increase in the population of Firmicutes. These results suggested that marine Desulfovibrio species, to be further isolated, are potential candidates for bioremediation of PG by immobilizing metals and metalloids thanks to sulfide production by these SRB.

  4. Reducing the extinction risk of stochastic populations via nondemographic noise

    Science.gov (United States)

    Be'er, Shay; Assaf, Michael

    2018-02-01

    We consider nondemographic noise in the form of uncertainty in the reaction step size and reveal a dramatic effect this noise may have on the stability of self-regulating populations. Employing the reaction scheme m A →k A but allowing, e.g., the product number k to be a priori unknown and sampled from a given distribution, we show that such nondemographic noise can greatly reduce the population's extinction risk compared to the fixed k case. Our analysis is tested against numerical simulations, and by using empirical data of different species, we argue that certain distributions may be more evolutionary beneficial than others.

  5. Effects of Variety and Postharvest Handling Practices on Microbial Population at Different Stages of the Value Chain of Fresh Tomato (Solanum lycopersicum) in Western Terai of Nepal.

    Science.gov (United States)

    Khadka, Ram B; Marasini, Madan; Rawal, Ranjana; Gautam, Durga M; Acedo, Antonio L

    2017-01-01

    Background . Fresh vegetables such as tomato should have low microbial population for safe consumption and long storage life. The aerobic bacterial count (ABC) and coliform bacterial count (CBC), yeast, and mold population are the most widely used microbial indicators in fresh vegetables which should be lower than 4 log CFU g -1 for safe consumption. The stages of the supply chain, postharvest handling methods, and crop varieties had significant effects on microbial population. ABC, CBC, yeast, and mold population were significantly highest ( P < 0.05) at retail market (5.59, 4.38, 2.60, and 3.14 log CFU g -1 , resp.), followed by wholesale market (4.72, 4.71, 2.43, and 2.44 log CFU g -1 , resp.), and were least at farm gate (3.89, 3.63, 2.38, and 2.03 log CFU g -1 , resp.). Improved postharvest practices (washing in clean water and grading and packaging in clean plastic crate) helped to reduce ABC, CBC, and mold population by 2.51, 32.70, and 29.86 percentage as compared to the conventional method (no washing and no grading and packaging in mud plastered bamboo baskets). Among varieties, Pusa ruby had the lowest microbial load of 2.58, 4.53, 0.96, and 1.77 log CFU g -1 for ABC, CBC, yeast, and mold count, respectively. Significantly negative correlation ( P < 0.05) was observed between fruit pH & ABC and pH & mold count. Although the microbial quality of fresh tomato is safe in the local market of western Terai of Nepal both in conventional and in improved practices however still it is essential to follow improved postharvest handling practices in production and marketing of newly introduced tomato cultivars (high-pH cultivars) for ensuring the safe availability of fresh tomato in the market.

  6. Development of a microbial population within a hot-drinks vending machine and the microbial load of vended hot chocolate drink.

    Science.gov (United States)

    Hall, A; Short, K; Saltmarsh, M; Fielding, L; Peters, A

    2007-09-01

    In order to understand the development of the microbial population within a hot-drinks vending machine a new machine was placed in a staff area of a university campus vending only hot chocolate. The machine was cleaned weekly using a detergent based protocol. Samples from the mixing bowl, dispense area, and drink were taken over a 19-wk period and enumerated using plate count agar. Bacillus cereus was identified using biochemical methods. Vended drinks were sampled at 0, 3, 6, and 9 min after vending; the hot chocolate powder was also sampled. Over the 1st 8 wk, a significant increase in the microbial load of the machine components was observed. By the end of the study, levels within the vended drink had also increased significantly. Inactivation of the automatic flush over a subsequent 5-wk period led to a statistically but not operationally significant increase in the microbial load of the dispense area and vended drink. The simple weekly clean had a significant impact on the microbial load of the machine components and the vended drink. This study demonstrated that a weekly, detergent-based cleaning protocol was sufficient to maintain the microbial population of the mixing bowl and dispense point in a quasi-steady state below 3.5 log CFU/cm2 ensuring that the microbial load of the vended drinks was maintained below 3.4 log CFU/mL. The microbial load of the drinks showed no significant changes over 9 min after vending, suggesting only spores are present in the final product.

  7. Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting

    DEFF Research Database (Denmark)

    Keraita, Bernard; Konradsen, Flemming; Drechsel, Pay

    2007-01-01

    OBJECTIVE: To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. METHODS: Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials...... were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. RESULTS: On average, 0.65 log units for indicator thermotolerant coliforms and 0.......4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes/ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0...

  8. Microbial removal of Fe(III) impurities from clay using dissimilatory iron reducers.

    Science.gov (United States)

    Lee, E Y; Cho, K S; Ryu, H W; Chang, Y K

    1999-01-01

    Fe(III) impurities, which detract refractoriness and whiteness from porcelain and pottery, could be biologically removed from low-quality clay by indigenous dissimilatory Fe(III)-reducing microorganisms. Insoluble Fe(III) in clay particles was leached out as soluble Fe(II), and the Fe(III) reduction reaction was coupled to the oxidation of sugars such as glucose, maltose and sucrose. A maximum removal of 44-45% was obtained when the relative amount of sugar was 5% (w/w; sugar/clay). By the microbial treatment, the whiteness of the clay was increased from 63.20 to 79.64, whereas the redness was clearly decreased from 13.47 to 3.55.

  9. Natural disturbance reduces disease risk in endangered rainforest frog populations.

    Science.gov (United States)

    Roznik, Elizabeth A; Sapsford, Sarah J; Pike, David A; Schwarzkopf, Lin; Alford, Ross A

    2015-08-21

    Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11-28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

  10. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  11. Microbial populations and activities of mangrove, restinga and Atlantic forest soils from Cardoso Island, Brazil.

    Science.gov (United States)

    Pupin, B; Nahas, E

    2014-04-01

    Mangroves provide a distinctive ecological environment that differentiates them from other ecosystems. This study deal to evaluate the frequency of microbial groups and the metabolic activities of bacteria and fungi isolated from mangrove, restinga and Atlantic forest soils. Soil samples were collected during the summer and winter at depths of 0-2, 2-5 and 5-10 cm. Except for fungi, the counts of the total, sporulating, Gram-negative, actinomycetes, nitrifying and denitrifying bacteria decreased significantly in the following order: Atlantic forest >mangrove > restinga. The counts of micro-organisms decreased by 11 and 21% from the surface to the 2-5 and 5-10 cm layers, but denitrifying bacteria increased by 44 and 166%, respectively. A larger growth of micro-organisms was verified in the summer compared with the winter, except for actinomycetes and fungi. The average frequency of bacteria isolated from mangrove, restinga and Atlantic forest soils was 95, 77 and 78%, and 93, 90 and 95% for fungi, respectively. Bacteria were amylolytic (33%), producers of acid phosphatase (79%) and solubilizers (18%) of inorganic phosphate. The proportions of fungi were 19, 90 and 27%. The mangrove soil studied had higher chemical characteristics than the Atlantic forest, but the high salinity may have restricted the growth of microbial populations. Estimates of the microbial counts and activities were important to elucidate the differences of mangrove ecosystem from restinga and Atlantic forest. © 2013 The Society for Applied Microbiology.

  12. Ecological distribution and population physiology defined by proteomics in a natural microbial community

    Science.gov (United States)

    Mueller, Ryan S.; Denef, Vincent J.; Kalnejais, Linda H.; Suttle, K. Blake; Thomas, Brian C.; Wilmes, Paul; Smith, Richard L.; Nordstrom, D. Kirk; McCleskey, R. Blaine; Shah, Menesh B.; VerBekmoes, Nathan C.; Hettich, Robert L.; Banfield, Jillian F.

    2010-01-01

    An important challenge in microbial ecology is developing methods that simultaneously examine the physiology of organisms at the molecular level and their ecosystem level interactions in complex natural systems. We integrated extensive proteomic, geochemical, and biological information from 28 microbial communities collected from an acid mine drainage environment and representing a range of biofilm development stages and geochemical conditions to evaluate how the physiologies of the dominant and less abundant organisms change along environmental gradients. The initial colonist dominates across all environments, but its proteome changes between two stable states as communities diversify, implying that interspecies interactions affect this organism's metabolism. Its overall physiology is robust to abiotic environmental factors, but strong correlations exist between these factors and certain subsets of proteins, possibly accounting for its wide environmental distribution. Lower abundance populations are patchier in their distribution, and proteomic data indicate that their environmental niches may be constrained by specific sets of abiotic environmental factors. This research establishes an effective strategy to investigate ecological relationships between microbial physiology and the environment for whole communities in situ.

  13. Changes in microbial populations and enzyme activities during the bioremediation of oil-contaminated soil.

    Science.gov (United States)

    Lin, Xin; Li, Xiaojun; Sun, Tieheng; Li, Peijun; Zhou, Qixing; Sun, Lina; Hu, Xiaojun

    2009-10-01

    In the process of bioremediation in the soil contaminated by different oil concentrations, the changes in the microbial numbers (bacteria and fungi) and the enzyme (catalase (CAT), polyphenol oxidase (PPO) and lipase) activities were evaluated over a 2-year period. The results showed that the microbial numbers after 2-year bioremediation were one to ten times higher than those in the initial. The changes in the bacterial and the fungal populations were different during the bioremediation, and the highest microbial numbers for bacteria and fungi were 5.51 x 10(9) CFU g(-1) dry soil in treatment 3 (10,000 mg kg(-1)) in the initial and 5.54 x 10(5) CFU g(-1) dry soil in treatment 5 (50,000 mg kg(-1)) after the 2-year bioremediation period, respectively. The CAT and PPO activities in the contaminated soil decreased with increasing oil concentration, while the lipase activity increased. The activities of CAT and PPO improved after the bioremediation, but lipase activity was on the contrary. The CAT activity was more sensible to the oil than others, and could be alternative to monitor the bioremediation process.

  14. Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

    Science.gov (United States)

    Maslov, Sergei; Sneppen, Kim

    2017-01-01

    Determinants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity. PMID:28051127

  15. Population characteristics may reduce the levels of individual call identity.

    Directory of Open Access Journals (Sweden)

    María del Mar Delgado

    Full Text Available Individual variability influences the demographic and evolutionary dynamics of spatially structured populations, and conversely ecological and evolutionary dynamics provide the context under which variations at the individual level occur. Therefore, it is essential to identify and characterize the importance of the different factors that may promote or hinder individual variability. Animal signaling is a prime example of a type of behavior that is largely dependent on both the features of individuals and the characteristics of the population to which they belong. After 10 years studying the dynamics of a population of a long-lived species, the eagle owl (Bubo bubo, we investigated the emergence and maintenance of traits that reveal individual identity by focusing on vocal features. We found that individuals inhabiting a high density population characterized by a relative lack of heterogeneity (in terms of prey availability and breeding success among breeding sites might be selected for reducing the levels of identity. Two non-mutually exclusive hypotheses may explain the structural call patterns we detected: (1 similarity in calls may be principally a consequence of the particular characteristics of the population; and (2 high density may encourage individuals to mimic each other's vocalizations in a cascade effect, leading to a widespread and unique communication network.

  16. Do roads reduce painted turtle (Chrysemys picta) populations?

    Science.gov (United States)

    Dorland, Alexandra; Rytwinski, Trina; Fahrig, Lenore

    2014-01-01

    Road mortality is thought to be a leading cause of turtle population decline. However, empirical evidence of the direct negative effects of road mortality on turtle population abundance is lacking. The purpose of this study was to provide a strong test of the prediction that roads reduce turtle population abundance. While controlling for potentially confounding variables, we compared relative abundance of painted turtles (Chrysemys picta) in 20 ponds in Eastern Ontario, 10 as close as possible to high traffic roads (Road sites) and 10 as far as possible from any major roads (No Road sites). There was no significant effect of roads on painted turtle relative abundance. Furthermore, our data do not support other predictions of the road mortality hypothesis; we observed neither a higher relative frequency of males to females at Road sites than at No Road sites, nor a lower average body size of turtles at Road than at No Road sites. We speculate that, although roads can cause substantial adult mortality in turtles, other factors, such as release from predation on adults and/or nests close to roads counter the negative effect of road mortality in some populations. We suggest that road mitigation for painted turtles can be limited to locations where turtles are forced to migrate across high traffic roads due, for example, to destruction of local nesting habitat or seasonal drying of ponds. This conclusion should not be extrapolated to other species of turtles, where road mortality could have a larger population-level effect than on painted turtles.

  17. Reduced inflammation in expanding populations of a neotropical bird species.

    Science.gov (United States)

    Bailly, Juliette; Garnier, Stéphane; Khimoun, Aurélie; Arnoux, Emilie; Eraud, Cyril; Goret, Jean-Yves; Luglia, Thomas; Gaucher, Philippe; Faivre, Bruno

    2016-10-01

    The loss of regulating agents such as parasites is among the most important changes in biotic interactions experienced by populations established in newly colonized areas. Under a relaxed parasite pressure, individuals investing less in costly immune mechanisms might experience a selective advantage and become successful colonizers as they re-allocate resources to other fitness-related traits. Accordingly, a refinement of the evolution of increased competitive ability (EICA) hypothesis proposed that immunity of invasive populations has evolved toward a reduced investment in innate immunity, the most costly component of immunity, and an increased humoral immunity that is less costly. Biogeographical approaches comparing populations between native and expansion ranges are particularly relevant in exploring this issue, but remain very scarce. We conducted a biogeographical comparison between populations of Spectacled Thrush ( Turdus nudigenis ) from the native area (South America) and from the expansion range (Caribbean islands). First, we compared haemosporidian prevalence and circulating haptoglobin (an acute-phase protein produced during inflammation). Second, we challenged captive birds from both ranges with Escherichia coli lipopolysaccharides ( LPS ) and measured postchallenge haptoglobin production and body mass change. Birds from the expansion range showed lower haemosporidian prevalence and lower levels of haptoglobin than birds from the native range. In addition, the inflammation elicited by LPS injection and its associated cost in terms of body mass loss were lower in birds from the expansion range than in birds from the native range. In accordance with the enemy release hypothesis, our results suggest that range expansion is associated with a reduced infection risk. Our study also supports the hypothesis that individuals from newly established populations have evolved mechanisms to dampen the inflammatory response and are in accordance with one prediction

  18. Using microbial desalination cells to reduce water salinity prior to reverse osmosis

    KAUST Repository

    Mehanna, Maha

    2010-01-01

    A microbial desalination cell (MDC) is a new method to reduce the salinity of one solution while generating electrical power from organic matter and bacteria in another (anode) solution. Substantial reductions in the salinity can require much larger volumes of the anode solution than the saline water, but any reduction of salinity will benefit the energy efficiency of a downstream reverse osmosis (RO) desalination system. We investigated here the use of an MDC as an RO pre-treatment method using a new type of air-cathode MDC containing three equally sized chambers. A single cycle of operation using a 1 g L -1 acetate solution reduced the conductivity of salt water (5 g L-1 NaCl) by 43 ± 6%, and produced a maximum power density of 480 mW m-2 with a coulombic efficiency of 68 ± 11%. A higher concentration of acetate (2 g L-1) reduced solution conductivity by 60 ± 7%, and a higher salt concentration (20 g L-1 NaCl) reduced solution conductivity by 50 ± 7%. The use of membranes with increased ion exchange capacities further decreased the solution conductivity by 63 ± 2% (20 g L-1 NaCl). These results demonstrate substantial (43-67%) desalination of water is possible using equal volumes of anode solution and salt water. These results show that MDC treatment could be used to substantially reduce salt concentrations and thus energy demands for downstream RO processing, while at the same time producing electrical power. © 2010 The Royal Society of Chemistry.

  19. Effect of buctril super (Bromoxynil herbicide on soil microbial biomass and bacterial population

    Directory of Open Access Journals (Sweden)

    Zafar Abbas

    2014-02-01

    Full Text Available The present study aimed to evaluate the effect of bromoxynil herbicide on soil microorganisms, with the hypothesis that this herbicide caused suppression in microbial activity and biomass by exerting toxic effect on them. Nine sites of Punjab province (Pakistan those had been exposed to bromoxynil herbicide for about last ten years designated as soil 'A' were surveyed in 2011 and samples were collected and analyzed for Microbial Biomass Carbon (MBC, Biomass Nitrogen (MBN, Biomass Phosphorus (MBP and bacterial population. Simultaneously, soil samples from the same areas those were not exposed to herbicide designated as soil 'B' were taken. At all the sites MBC, MBN and MBP ranged from 131 to 457, 1.22 to 13.1 and 0.59 to 3.70 µg g-1 in the contaminated soils (Soil A, which was 187 to 573, 1.70 to 14.4 and 0.72 to 4.12 µg g-1 in the soils without contamination (soil B. Bacterial population ranged from 0.67 to 1.84x10(8 and 0.87 to 2.37x10(8 cfu g-1 soil in the soils A and B, respectively. Bromoxynil residues ranged from 0.09 to 0.24 mg kg-1 at all the sites in soil A. But no residues were detected in the soil B. Due to lethal effect of bromoxynil residues on the above parameters, considerable decline in these parameters was observed in the contaminated soils. Results depicted that the herbicide had left toxic effects on soil microbial parameters, thus confirmed that continuous use of this herbicide affected the quality of soil and sustainable crop production.

  20. Microbial quality of food available to populations of differing socioeconomic status.

    Science.gov (United States)

    Koro, Marlen E; Anandan, Shivanthi; Quinlan, Jennifer J

    2010-05-01

    Low SES has been shown to be linked to poorer-quality diets, decreased consumption of fresh produce, and an increased reliance on small retail stores. The objective of this research was to determine if there is a difference in the microbial quality and potential safety of food available to low-SES versus high-SES populations at the retail level. Aerobic plate count (APC); yeast and mold counts (Y & M); and total coliforms were determined in ready-to-eat (RTE) greens, pre-cut watermelon, broccoli, strawberries, cucumbers, milk, and orange juice and compared among products purchased in stores in low- versus those purchased in high-SES neighborhoods between June 2005 and September 2006. APC, fecal coliforms, and E. coli in ground beef and the presence of Salmonella and Campylobacter in chicken were also compared. Results showed higher microbial loads on produce from markets in low-SES areas. Significant differences observed included (1) APC and Y&M in RTE greens, (2) APC and Y&M in strawberries, and (3) YMCs in cucumbers. No difference was detected in the level of pathogens in raw meat and poultry; however, the APC in ground beef available in high-SES markets was significantly higher compared with that found in low-SES markets. The results presented here indicate that populations of low SES may be more likely to experience produce of poorer microbial quality, which may have an impact on both the appeal and potential safety of the produce. 2010 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  1. Effect of common pesticides used in the Niger Delta basin of southern Nigeria on soil microbial populations.

    Science.gov (United States)

    Ekundayo, E O

    2003-11-01

    The effects of eleven pesticides on the populations of bacteria, actinomycetes, fungi and protozoa was investigated by treating a garden soil with their recommended rates. The microbial populations were estimated using the standard plate-count technique. Of the 11 pesticides investigated, phenylmercuric acetate (agrosan) at 50 microg g(-1) inhibited bacterial density the most, i.e. from 4,600,000 to 220 cells g(-1). The pesticides were Pentachloronitrobenzene (PCNB), tetramethylmethylthiuram disulphide (thiram), 1-naphthylmethylcarbamate (Vetox 85), 1,2,3,4,5,6-hexachlorocyclohexane (Gammalin 20), phenylmercuric acetate (Agrosan), tetrachloroterephthalic acid (Dacthal), 4-nitrophenyl-2-nitro-4-trifluoromethylphenyl ether (Preforan), 2-ethyl-6-methyl-N-2-methoxy-1-methyl ethyl-chloroacetanide (Dual), Benlate, Brestan and Gramoxone. Pentachloronitrobenzene (PCNB) at 240,000 microg g(-1) reduced bacterial population from 4,600,000 to 2,100 cells g(-1), whereas tetramethylthiuram disulphide (thiram) at 100 microg g(-1) suppressed it by 2 log orders of magnitude. Soil application of 1-naphthylmethylcarbamate (Vetox 85) at 100 microg g(-1) and 1,2,3,4,5,6,-hexachlorocyclohexane (Gamalin 20) at 1,300 microg g(-1) repressed the bacterial numbers by 2 log orders of magnitude each. Pentachloronitrobenzene reduced the actinomycetes density from 340,000 to 320 cells g(-1) and completely eliminated all fungal and protozoan propagules from the soil. The Gammalin 20 completely wiped out all the fungi, whereas phenylmercuric acetate totally eliminated all the protozoa and reduced the fungal population from 34,000 to 60 cells g(-1). In general, protozoa and fungi were more susceptible to fungicides than bacteria and actinomycetes. Pentachloronitrobenzene, 1,2,3,4,5,6,-hexachlorocyclohexane and phenylmercuric acetate were toxic particularly to soil microorganisms, whereas the herbicides dacthal, Preforan and Dual were quite harmless in soil at application rates of 0.1, 0.06 and 0

  2. Soil microbial population and nitrogen fixation in peanut under fly ash and sewage sludge

    International Nuclear Information System (INIS)

    Sarkar, S.; Khan, A.R.

    2002-06-01

    Surface disposal of municipal sludge and industrial wastes is an old practice that recently has been attracting concerns due to associated soil, air and water pollution. Wise utilization and recycling of these wastes in agricultural land brings in the much-needed organic and mineral matter to the soil. However, the assimilative capacity of the soil with respect to its physical, chemical and biological properties and the performance of crop grown, needs thorough investigation. Industrial wastes like fly ash (FA) from Thermal Power Plant and Sewage Sludge from municipal and city activities (untreated and treated CW) are some such important organic based waste resources having a potentiality for recycling in the agricultural land. The characteristics of these wastes with respect to their pH, plant nutrient and heavy metals content differs. Fly ash, being a burnt residue of coal, is rich in essential mineral elements and also has capacity in neutralizing soil acidity and supplying the nutrients to the plants (Molliner and Street, 1982). Sewage sludge application also has a significant influence on the physical, chemical and biological properties of soil. The soil biological systems can be altered by new energy input for the organisms, which is reflected by changes in the micro and macrobiological populations, in turn influencing the synthesis and decomposition of soil organic substances, nutrient availability, interactions with soil inorganic components and other exchanges with physical and chemical properties (Clapp et al, 1986). So far, much information is known regarding changes in physico-chemical properties of soil and performance of crop due to applications of such wastes. However, long term studies are needed to improve our understanding of the effects of land application of such wastes on soil biological systems (McGrath et al. 1995). It is known that native soil microbial population is responsible for decomposition of organic matter and recycling of nutrients

  3. In situ examination of microbial populations in a model drinking water distribution system

    DEFF Research Database (Denmark)

    Martiny, Adam Camillo; Nielsen, Alex Toftgaard; Arvin, Erik

    2002-01-01

    A flow cell set-up was used as a model drinking water distribution system to analyze the in situ microbial population. Biofilm growth was followed by transmission light microscopy for 81 days and showed a biofilm consisting of microcolonies separated by a monolayer of cells. Protozoans (ciliates...... of a mixed population of α- and β-Proteobacteria. 65 strains from the inlet water and 20 from the biofilm were isolated on R2A agar plates and sorted into groups with amplified rDNA restriction analysis. The 16S rDNA gene was sequenced for representatives of the abundant groups. A phylogenetic analysis...... revealed that the majority of the isolated strains from the bulk water and biofilm were affiliated to the family of Comamonadaceae in the β-lineage of Proteobacteria. The majority of the strains from the α-lineage were affiliated to the family of Sphingomonadaceae. We were unable to detect any strains from...

  4. Significant Association between Sulfate-Reducing Bacteria and Uranium-Reducing Microbial Communities as Revealed by a Combined Massively Parallel Sequencing-Indicator Species Approach▿ †

    Science.gov (United States)

    Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K.; Jardine, Philip M.; Zhou, Jizhong; Criddle, Craig S.; Marsh, Terence L.; Tiedje, James M.

    2010-01-01

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared. PMID:20729318

  5. Significant association between sulfate-reducing bacteria and uranium-reducing microbial communities as revealed by a combined massively parallel sequencing-indicator species approach.

    Science.gov (United States)

    Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K; Jardine, Philip M; Zhou, Jizhong; Criddle, Craig S; Marsh, Terence L; Tiedje, James M

    2010-10-01

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared.

  6. Do roads reduce painted turtle (Chrysemys picta populations?

    Directory of Open Access Journals (Sweden)

    Alexandra Dorland

    Full Text Available Road mortality is thought to be a leading cause of turtle population decline. However, empirical evidence of the direct negative effects of road mortality on turtle population abundance is lacking. The purpose of this study was to provide a strong test of the prediction that roads reduce turtle population abundance. While controlling for potentially confounding variables, we compared relative abundance of painted turtles (Chrysemys picta in 20 ponds in Eastern Ontario, 10 as close as possible to high traffic roads (Road sites and 10 as far as possible from any major roads (No Road sites. There was no significant effect of roads on painted turtle relative abundance. Furthermore, our data do not support other predictions of the road mortality hypothesis; we observed neither a higher relative frequency of males to females at Road sites than at No Road sites, nor a lower average body size of turtles at Road than at No Road sites. We speculate that, although roads can cause substantial adult mortality in turtles, other factors, such as release from predation on adults and/or nests close to roads counter the negative effect of road mortality in some populations. We suggest that road mitigation for painted turtles can be limited to locations where turtles are forced to migrate across high traffic roads due, for example, to destruction of local nesting habitat or seasonal drying of ponds. This conclusion should not be extrapolated to other species of turtles, where road mortality could have a larger population-level effect than on painted turtles.

  7. Ambient ultraviolet radiation in the Arctic reduces root biomass and alters microbial community composition but has no effects on microbial biomass

    DEFF Research Database (Denmark)

    Rinnan, R.; Keinänen, M.M.; Kasurinen, A.

    2005-01-01

    We assessed the effects of ambient solar ultraviolet (UV) radiation on below-ground parameters in an arctic heath in north-eastern Greenland. We hypothesized that the current UV fluxes would reduce root biomass and mycorrhizal colonization and that these changes would lead to lower soil microbial...... biomass and altered microbial community composition. These hypotheses were tested on cored soil samples from a UV reduction experiment with three filter treatments (Mylar, 60% UV-B reduction; Lexan, up to 90% UV-B reduction+UV-A reduction; UV transparent Teflon, filter control) and an open control...... treatment in two study sites after 3 years' manipulation. Reduction of both UV-A and UV-B radiation caused over 30% increase in the root biomass of Vaccinium uliginosum, which was the dominant plant species. UV reduction had contrasting effects on ericoid mycorrhizal colonization of V. uliginosum roots...

  8. Microbial Anaerobic Ammonium Oxidation Under Iron Reducing Conditions, Alternative Electron Acceptors

    Science.gov (United States)

    Ruiz-Urigüen, M.; Jaffe, P. R.

    2015-12-01

    Autotrophic Acidimicrobiaceae-bacterium named A6 (A6), part of the Actinobacteria phylum have been linked to anaerobic ammonium (NH4+) oxidation under iron reducing conditions. These organisms obtain their energy by oxidizing NH4+ and transferring the electrons to a terminal electron acceptor (TEA). Under environmental conditions, the TEAs are iron oxides [Fe(III)], which are reduced to Fe(II), this process is known as Feammox. Our studies indicate that alternative forms of TEAs can be used by A6, e.g. iron rich clays (i.e. nontronite) and electrodes in bioelectrochemical systems such as Microbial Electrolysis Cells (MECs), which can sustain NH4+removal and A6 biomass production. Our results show that nontronite can support Feammox and promote bacterial cell production. A6 biomass increased from 4.7 x 104 to 3.9 x 105 cells/ml in 10 days. Incubations of A6 in nontronite resulted in up to 10 times more NH4+ removal and 3 times more biomass production than when ferrihydrite is used as the Fe(III) source. Additionally, Fe in nontronite can be reoxidized by aeration and A6 can reutilize it; however, Fe is still finite in the clay. In contrast, in MECs, A6 harvest electrons from NH4+ and use an anode as an unlimited TEA, as a result current is produced. We operated multiple MECs in parallel using a single external power source, as described by Call & Logan (2011). MECs were run with an applied voltage of 0.7V and different growing mediums always containing initial 5mM NH4+. Results show that current production is favored when anthraquinone-2,6-disulfonate (AQDS), an electron shuttled, is present in the medium as it facilitates the transfer of electrons from the bacterial cell to the anode. Additionally, A6 biomass increased from 1 x 104 to 9.77 x 105cells/ml in 14 days of operation. Due to Acidimicrobiaceae-bacterium A6's ability to use various TEAs, MECs represent an alternative, iron-free form, for optimized biomass production of A6 and its application in NH4

  9. Melimine-Coated Antimicrobial Contact Lenses Reduce Microbial Keratitis in an Animal Model.

    Science.gov (United States)

    Dutta, Debarun; Vijay, Ajay K; Kumar, Naresh; Willcox, Mark D P

    2016-10-01

    To determine the ability of antimicrobial peptide melimine-coated contact lenses to reduce the incidence of microbial keratitis (MK) in a rabbit model of contact lens wear. In vitro antimicrobial activity of melimine-coated contact lenses was determined against Pseudomonas aeruginosa by viable count and a radiolabeled assay. The amount of lipopolysaccharide (LPS) associated with bacteria bound to melimine-coated and control lenses was determined. Ocular swabs from rabbit eyes were collected for assessment of ocular microflora. A rabbit model for MK was developed that used overnight wear of contact lenses colonized by P. aeruginosa in the absence of a corneal scratch. During lens wear, detailed ocular examinations were performed, and the incidence of MK was investigated. Bacteria associated with worn lenses and infected corneas were determined by viable plate count. Inhibition in viable and total P. aeruginosa adhesion by melimine-coated contact lenses was 3.1 log10 and 0.4 log10, respectively. After colonization, the amount of LPS on lenses was approximately the same with or without melimine. Gram-positive bacteria were found in all the ocular swabs followed by fungus (42%). Melimine-coated lens wear was protective and significantly (odds ratio 10.12; P = 0.012) reduced the incidence of P. aeruginosa-driven MK in the rabbit model. The antimicrobial lenses were associated with significantly (P lenses can produce MK without corneal epithelial defect in an animal model. Melimine-coated contact lenses reduced the incidence of MK associated with P. aeruginosa in vivo. Development of MK requires viable bacteria adherent to contact lenses, and bacterial debris adherent at the lens surface did not cause keratitis.

  10. Performance and microbial community dynamics of a sulfate-reducing bioreactor treating coal generated acid mine drainage.

    Science.gov (United States)

    Burns, Andrew S; Pugh, Charles W; Segid, Yosief T; Behum, Paul T; Lefticariu, Liliana; Bender, Kelly S

    2012-06-01

    The effectiveness of a passive flow sulfate-reducing bioreactor processing acid mine drainage (AMD) generated from an abandoned coal mine in Southern Illinois was evaluated using geochemical and microbial community analysis 10 months post bioreactor construction. The results indicated that the treatment system was successful in both raising the pH of the AMD from 3.09 to 6.56 and in lowering the total iron level by 95.9%. While sulfate levels did decrease by 67.4%, the level post treatment (1153 mg/l) remained above recommended drinking water levels. Stimulation of biological sulfate reduction was indicated by a +2.60‰ increase in δ(34)S content of the remaining sulfate in the water post-treatment. Bacterial community analysis targeting 16S rRNA and dsrAB genes indicated that the pre-treated samples were dominated by bacteria related to iron-oxidizing Betaproteobacteria, while the post-treated water directly from the reactor outflow was dominated by sequences related to sulfur-oxidizing Epsilonproteobacteria and complex carbon degrading Bacteroidetes and Firmicutes phylums. Analysis of the post-treated water, prior to environmental release, revealed that the community shifted back to predominantly iron-oxidizing Betaproteobacteria. DsrA analysis implied limited diversity in the sulfate-reducing population present in both the bioreactor outflow and oxidation pond samples. These results support the use of passive flow bioreactors to lower the acidity, metal, and sulfate levels present in the AMD at the Tab-Simco mine, but suggest modifications of the system are necessary to both stimulate sulfate-reducing bacteria and inhibit sulfur-oxidizing bacteria.

  11. Microbial populations in an agronomically managed mollisol treated with simulated acid rain

    International Nuclear Information System (INIS)

    Miller, K.W.; Cole, M.A.; Banwart, W.L.

    1991-01-01

    A fertile well-buffered mollisol (Flanagan silt loam, fine montmorillonitic mesic Aquic Arguidoll) under cultivation with corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] was subjected to simulated rain of pH 5.6, 4.2, and 3.0, while moisture-activated rain exclusion shelters provided protection from ambient rain. Soil was sampled to a depth of 3 cm on four dates throughout the 1985 growing season. The following microorganisms were enumerated by plate counts or most probable number: general heterotrophic bacteria, general soil fungi, free-living N-fixing bacteria, fluorescent pseudomonads, autotrophic ammonium-oxidizing, nitrite-oxidizing, and thio-sulfate-oxidizing bacteria. The ANOVA was used to determine the combined and individual effects of rain treatments, crop field, and sampling date. Crop field and sampling date affected microbial numbers more than rain treatments. Overall, rain treatment effects were limited to nitrite-oxidizing bacteria; lower numbers occurred in the corn field in subplots treated with rain of pH 4.2 and 3.0, and in the soybean field treated with rain of pH 3.0. The trend was strongest in June and July. In the corn field in subplots treated with rain of pH 3.0, numbers of thiosulfate-oxidizing bacteria were higher an numbers of general heterotrophic bacteria were lower; however, these trends were comparatively weak. Rain treatments caused essentially no decrease in soil pH, suggesting that acid rain constituents affect certain microbial populations without causing overt changes in pH. Because they appear to be unusually sensitive, nitrite-oxidizing bacteria could be used as experimental indicators of changes in soil microbial communities subjected to acid rain

  12. Distribution of microbial populations and their relationship with environmental variables in the North Yellow Sea, China

    Science.gov (United States)

    Bai, Xiaoge; Wang, Min; Liang, Yantao; Zhang, Zhifeng; Wang, Fang; Jiang, Xuejiao

    2012-03-01

    In order to understand the large-scale spatial distribution characteristics of picoplankton, nanophytoplankton and virioplankton and their relationship with environmental variables in coastal and offshore waters, flow cytometry (FCM) was used to analyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea (NYS). The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer. For the surface layer, picoeukaryotes were abundant in the near-shore waters, Synechococcus was abundant in the offshore areas, and bacterial and viral abundances were high in the near-shore waters around the Liaodong peninsula. In the near-shore waters, no significant vertical variation of picophytoplankton (0.2-2μm) abundance was found. However, the nanophytoplankton abundance was higher in the upper layers (from the surface to 10 m depth) than in the bottom layer. For the offshore waters, both pico- and nanophytoplankton (2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass (NYSCWM). But, for the vertical distribution of virus and bacteria abundance, no significant variation was observed in both near-shore and offshore waters. Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses. Viruses showed a positive correlation with bacterial abundance, suggesting that the bacteriophage might be prominent for virioplankton (about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.

  13. Microbial diversity in soil : Selection of microbial populations by plant and soil type and implications for disease suppressiveness

    NARCIS (Netherlands)

    Garbeva, P; van Veen, JA; van Elsas, JD

    2004-01-01

    An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats. The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms is involved in important soil

  14. Oxygen-Reducing Biocathodes Operating with Passive Oxygen Transfer in Microbial Fuel Cells

    KAUST Repository

    Xia, Xue

    2013-02-19

    Oxygen-reducing biocathodes previously developed for microbial fuel cells (MFCs) have required energy-intensive aeration of the catholyte. To avoid the need for aeration, the ability of biocathodes to function with passive oxygen transfer was examined here using air cathode MFCs. Two-chamber, air cathode MFCs with biocathodes produced a maximum power density of 554 ± 0 mW/m 2, which was comparable to that obtained with a Pt cathode (576 ± 16 mW/m2), and 38 times higher than that produced without a catalyst (14 ± 3 mW/m2). The maximum current density with biocathodes in this air-cathode MFC was 1.0 A/m2, compared to 0.49 A/m2 originally produced in a two-chamber MFC with an aqueous cathode (with cathode chamber aeration). Single-chamber, air-cathode MFCs with the same biocathodes initially produced higher voltages than those with Pt cathodes, but after several cycles the catalytic activity of the biocathodes was lost. This change in cathode performance resulted from direct exposure of the cathodes to solutions containing high concentrations of organic matter in the single-chamber configuration. Biocathode performance was not impaired in two-chamber designs where the cathode was kept separated from the anode solution. These results demonstrate that direct-air biocathodes can work very well, but only under conditions that minimize heterotrophic growth of microorganisms on the cathodes. © 2013 American Chemical Society.

  15. 2009 MICROBIAL POPULATION BIOLOGY GORDON RESEARCH CONFERENCES JULY 19-24,2009

    Energy Technology Data Exchange (ETDEWEB)

    ANTHONY DEAN

    2009-07-24

    The 2009 Gordon Conference on Microbial Population Biology will cover a diverse range of cutting edge issues in the microbial sciences and beyond. Firmly founded in evolutionary biology and with a strongly integrative approach, past Conferences have covered a range of topics from the dynamics and genetics of adaptation to the evolution of mutation rate, community ecology, evolutionary genomics, altruism, and epidemiology. The 2009 Conference is no exception, and will include sessions on the evolution of infectious diseases, social evolution, the evolution of symbioses, experimental evolution, adaptive landscapes, community dynamics, and the evolution of protein structure and function. While genomic approaches continue to make inroads, broadening our knowledge and encompassing new questions, the conference will also emphasize the use of experimental approaches to test hypotheses decisively. As in the past, this Conference provides young scientists and graduate students opportunities to present their work in poster format and exchange ideas with leading investigators from a broad spectrum of disciplines. This meeting is never dull: some of the most significant and contentious issues in biology have been thrashed out here. The 2009 meeting will be no exception.

  16. Effective photodynamic therapy against microbial populations in human deep tissue abscess aspirates.

    Science.gov (United States)

    Haidaris, Constantine G; Foster, Thomas H; Waldman, David L; Mathes, Edward J; McNamara, Joanne; Curran, Timothy

    2013-10-01

    The primary therapy for deep tissue abscesses is drainage accompanied by systemic antimicrobial treatment. However, the long antibiotic course required increases the probability of acquired resistance, and the high incidence of polymicrobial infections in abscesses complicates treatment choices. Photodynamic therapy (PDT) is effective against multiple classes of organisms, including those displaying drug resistance, and may serve as a useful adjunct to the standard of care by reduction of abscess microbial burden following drainage. Aspirates were obtained from 32 patients who underwent image-guided percutaneous drainage of the abscess cavity. The majority of the specimens (24/32) were abdominal, with the remainder from liver and lung. Conventional microbiological techniques and nucleotide sequence analysis of rRNA gene fragments were used to characterize microbial populations from abscess aspirates. We evaluated the sensitivity of microorganisms to methylene blue-sensitized PDT in vitro both within the context of an abscess aspirate and as individual isolates. Most isolates were bacterial, with the fungus Candida tropicalis also isolated from two specimens. We examined the sensitivity of these microorganisms to methylene blue-PDT. Complete elimination of culturable microorganisms was achieved in three different aspirates, and significant killing (P abscess treatment. © 2013 Wiley Periodicals, Inc.

  17. Effects of replacing dietary starch with neutral detergent-soluble fibre on ruminal fermentation, microbial synthesis and populations of ruminal cellulolytic bacteria using the rumen simulation technique (RUSITEC).

    Science.gov (United States)

    Zhao, X H; Liu, C J; Liu, Y; Li, C Y; Yao, J H

    2013-12-01

    A rumen simulation technique (RUSITEC) apparatus with eight 800 ml fermenters was used to investigate the effects of replacing dietary starch with neutral detergent-soluble fibre (NDSF) by inclusion of sugar beet pulp in diets on ruminal fermentation, microbial synthesis and populations of ruminal cellulolytic bacteria. Experimental diets contained 12.7, 16.4, 20.1 or 23.8% NDSF substituted for starch on a dry matter basis. The experiment was conducted over two independent 15-day incubation periods with the last 8 days used for data collection. There was a tendency that 16.4% NDSF in the diet increased the apparent disappearance of organic matter (OM) and neutral detergent fibre (NDF). Increasing dietary NDSF level increased carboxymethylcellulase and xylanase activity in the solid fraction and apparent disappearance of acid detergent fibre (ADF) but reduced the 16S rDNA copy numbers of Ruminococcus albus in both liquid and solid fractions and R. flavefaciens in the solid fraction. The apparent disappearance of dietary nitrogen (N) was reduced by 29.6% with increased dietary NDSF. Substituting NDSF for starch appeared to increase the ratios of acetate/propionate and methane/volatile fatty acids (VFA) (mol/mol). Replacing dietary starch with NDSF reduced the daily production of ammonia-N and increased the growth of the solid-associated microbial pellets (SAM). Total microbial N flow and efficiency of microbial synthesis (EMS), expressed as g microbial N/kg OM fermented, tended to increase with increased dietary NDSF, but the numerical increase did not continue as dietary NDSF exceeded 20.1% of diet DM. Results suggested that substituting NDSF for starch up to 16.4% of diet DM increased digestion of nutrients (except for N) and microbial synthesis, and further increases (from 16.4% to 23.8%) in dietary NDSF did not repress microbial synthesis but did significantly reduce digestion of dietary N. © 2012 Blackwell Verlag GmbH.

  18. Effect of moisture, organic matter, microbial population and fortification level on dissipation of pyraclostrobin in soils.

    Science.gov (United States)

    Reddy, S Navakishore; Gupta, Suman; Gajbhiye, Vijay T

    2013-09-01

    The dissipation of pyraclostrobin, a strobilurin fungicide, in soil was found to be influenced by soil moisture, organic matter content and microbial population. Among the different moisture regimes, dissipation was faster under submerged condition (T1/2 10 days) followed by field capacity (T1/2 28.7 days) and in dry soil (T1/2 41.8 days). Use of sludge at 5 % level to Inceptisol favoured a faster dissipation of pyraclostrobin, whereas a slower rate of dissipation was observed in partial organic matter removed soil as compared to normal soil. Slower rate of dissipation was also observed in sterile soil (T1/2 47 days) compared to normal soil. Pyraclostrobin dissipated faster in Vertisol (T1/2 21.8 days) than in Inceptisol (T1/2 28.7 days). No significant difference in the dissipation rate was observed at 1 and 10 μg g(-1) fortification levels.

  19. Sheep fed with banana leaf hay reduce ruminal protozoa population.

    Science.gov (United States)

    Freitas, Cláudio Eduardo Silva; Duarte, Eduardo Robson; Alves, Dorismar David; Martinele, Isabel; D'Agosto, Marta; Cedrola, Franciane; de Moura Freitas, Angélica Alves; Dos Santos Soares, Franklin Delano; Beltran, Makenzi

    2017-04-01

    A ciliate protozoa suppression can reduce methane production increasing the energy efficiency utilization by ruminants. The physicochemical characteristics of rumen fluid and the profile of the rumen protozoa populations were evaluated for sheep fed banana leaf hay in replacement of the Cynodon dactylon cv. vaqueiro hay. A total of 30 male sheep were raised in intensive system during 15 days of adaptation and 63 days of experimental period. The animals were distributed in a completely randomized design that included six replicates of five treatments with replacement levels (0, 25, 50, 75, and 100%) of the grass vaquero for the banana leaf hay. Samples of fluid were collected directly from the rumen with sterile catheters. Color, odor, viscosity, and the methylene blue reduction potential (MBRP) were evaluated and pH estimated using a digital potentiometer. After decimal dilutions, counts of genus protozoa were performed in Sedgewick Rafter chambers. The averages of pH, MBRP, color, odor, and viscosity were not influenced by the inclusion of the banana leaf hay. However, the total number of protozoa and Entodinium spp. population significantly decreased at 75 and 100% inclusions of banana leaf hay as roughage.

  20. Reduced Nutrient Excretion and Environmental Microbial Load with the Addition of a Combination of Enzymes and Direct-Fed Microbials to the Diet of Broiler Chickens

    Directory of Open Access Journals (Sweden)

    MFFM Praes

    2016-03-01

    Full Text Available Abstract This study evaluated the effects of the dietary inclusion of an enzyme blend and a direct-fed microbials in broiler diets on litter production and quality. In total, 900 Cobb 500(r broiler chicks were distributed according to a completely randomized design into 4 treatments and 9 replicates of 25 birds each. Broilers were reared from 1 to 42 days of age. The treatments consisted of the following diets: NC: negative control; DFM: NC + 500 ppm of direct-fed microbials product (DFM, containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm of xylanase; DFM+E: ENZ + DFM. Birds and litter were weighed at the start and end of the rearing period, for litter production and waste ratio (Rw determination. Litter samples were analyzed for dry matter (DM content, total and thermotolerant coliform counts, nutrient composition (nitrogen (N, phosphorous (P and potassium (K, and fiber fraction (neutral detergent fiber (NDF, acid detergent fiber (ADF and lignin. The dietary inclusion of the evaluated additivesdid not influence litter production or Rw; however, ADF (%, NDF (kg and kg/kg DM litter, and total and thermotolerant coliform counts were reduced, and N content increased in the litter. The diets containing enzymes (ENZ and DFM+E reduced litter P content. The addition of exogenous enzymes and their combination with a DFM based on Bacillus spp .Did not affect waste production, and reduced litter microbial load, and the contents of P and insoluble fiber in the litter.

  1. Effect of Plants Containing Secondary Compounds with Palm Oil on Feed Intake, Digestibility, Microbial Protein Synthesis and Microbial Population in Dairy Cows

    Directory of Open Access Journals (Sweden)

    N. Anantasook

    2013-06-01

    Full Text Available The objective of this study was to determine the effect of rain tree pod meal with palm oil supplementation on feed intake, digestibility, microbial protein synthesis and microbial populations in dairy cows. Four, multiparous early-lactation Holstein-Friesian crossbred (75% lactating dairy cows with an initial body weight (BW of 405±40 kg and 36±8 DIM were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. The four dietary treatments were un-supplementation (control, supplementation with rain tree pod meal (RPM at 60 g/kg, supplementation with palm oil (PO at 20 g/kg, and supplementation with RPM at 60 g/kg and PO at 20 g/kg (RPO, of total dry matter intake. The cows were offered concentrates, at a ratio of concentrate to milk production of 1:2, and chopped 30 g/kg of urea treated rice straw was fed ad libitum. The RPM contained condensed tannins and crude saponins at 88 and 141 g/kg of DM, respectively. It was found that supplementation with RPM and/or PO to dairy cows diets did not show negative effects on feed intake and ruminal pH and BUN at any times of sampling (p>0.05. However, RPM supplementation resulted in lower crude protein digestibility, NH3-N concentration and number of proteolytic bacteria. It resulted in greater allantoin absorption and microbial crude protein (p<0.05. In addition, dairy cows showed a higher efficiency of microbial N supply (EMNS in both RPM and RPO treatments. Moreover, NDF digestibility and cellulolytic bacteria numbers were highest in RPO supplementation (p<0.05 while, supplementation with RPM and/or PO decreased the protozoa population in dairy cows. Based on this study, supplementation with RPM and/or PO in diets could improve fiber digestibility, microbial protein synthesis in terms of quantity and efficiency and microbial populations in dairy cows.

  2. Range expansions transition from pulled to pushed waves with increasing cooperativity in an experimental microbial population

    Science.gov (United States)

    Gandhi, Saurabh; Yurtsev, Eugene; Korolev, Kirill; Gore, Jeff

    Range expansions are becoming more frequent due to environmental changes and rare long distance dispersal, often facilitated by anthropogenic activities. Simple models in theoretical ecology explain many emergent properties of range expansions, such as a constant expansion velocity, in terms of organism-level properties such as growth and dispersal rates. Testing these quantitative predictions in natural populations is difficult because of large environmental variability. Here, we used a controlled microbial model system to study range expansions of populations with and without intra-specific cooperativity. For non-cooperative growth, the expansion dynamics were dominated by population growth at the low-density front, which pulled the expansion forward. We found these expansions to be in close quantitative agreement with the classical theory of pulled waves by Fisher and Skellam, suitably adapted to our experimental system. However, as cooperativity increased, the expansions transitioned to being pushed, i.e. controlled by growth in the bulk as well as in the front. Although both pulled and pushed waves expand at a constant velocity and appear otherwise similar, their distinct dynamics leads to very different evolutionary consequences. Given the prevalence of cooperative growth in nature, understanding the effects of cooperativity is essential to managing invading species and understanding their evolution.

  3. Decline in Performance of Biochemical Reactors for Sulphate Removal from Mine-Influenced Water is Accompanied by Changes in Organic Matter Characteristics and Microbial Population Composition

    Directory of Open Access Journals (Sweden)

    Parissa Mirjafari

    2016-03-01

    Full Text Available Successful long-term bioremediation of mining-influenced water using complex organic matter and naturally-occurring microorganisms in sub-surface flow constructed wetlands requires a balance between easily and more slowly degrading material. This can be achieved by combining different types of organic materials. To provide guidance on what mixture combinations to use, information is needed on how the ratio of labile to recalcitrant components affects the degradation rate and the types of microbial populations supported. To investigate this, different ratios of wood and hay were used in up-flow column bioreactors treating selenium- and sulphate-containing synthetic mine-influenced water. The degradation rates of crude fibre components appeared to be similar regardless of the relative amounts of wood and hay. However, the nature of the degradation products might have differed in that those produced in the hay-rich bioreactors were more biodegradable and supported high sulphate-reduction rates. Microorganisms in the sulphate-reducing and cellulose-degrading inocula persisted in the bioreactors indicating that bio-augmentation was effective. There was a shift in microbial community composition over time suggesting that different microbial groups were involved in decomposition of more recalcitrant material. When dissolved organic carbon (DOC was over-supplied, the relative abundance of sulphate-reducers was low even through high sulphate-reduction rates were achieved. As DOC diminished, sulphate-reducers become more prevalent and their relative abundance correlated with sulphate concentrations rather than sulphate-reduction rate.

  4. Reducing the activity and secretion of microbial antioxidants enhances the immunogenicity of BCG.

    Directory of Open Access Journals (Sweden)

    Shanmugalakshmi Sadagopal

    Full Text Available In early clinical studies, the live tuberculosis vaccine Mycobacterium bovis BCG exhibited 80% protective efficacy against pulmonary tuberculosis (TB. Although BCG still exhibits reliable protection against TB meningitis and miliary TB in early childhood it has become less reliable in protecting against pulmonary TB. During decades of in vitro cultivation BCG not only lost some genes due to deletions of regions of the chromosome but also underwent gene duplication and other mutations resulting in increased antioxidant production.To determine whether microbial antioxidants influence vaccine immunogenicity, we eliminated duplicated alleles encoding the oxidative stress sigma factor SigH in BCG Tice and reduced the activity and secretion of iron co-factored superoxide dismutase. We then used assays of gene expression and flow cytometry with intracellular cytokine staining to compare BCG-specific immune responses in mice after vaccination with BCG Tice or the modified BCG vaccine. Compared to BCG, the modified vaccine induced greater IL-12p40, RANTES, and IL-21 mRNA in the spleens of mice at three days post-immunization, more cytokine-producing CD8+ lymphocytes at the peak of the primary immune response, and more IL-2-producing CD4+ lymphocytes during the memory phase. The modified vaccine also induced stronger secondary CD4+ lymphocyte responses and greater clearance of challenge bacilli.We conclude that antioxidants produced by BCG suppress host immune responses. These findings challenge the hypothesis that the failure of extensively cultivated BCG vaccines to prevent pulmonary tuberculosis is due to over-attenuation and suggest instead a new model in which BCG evolved to produce more immunity-suppressing antioxidants. By targeting these antioxidants it may be possible to restore BCG's ability to protect against pulmonary TB.

  5. Final Report: Stability of U (VII) and Tc (VII) Reducing Microbial Communities To Environmental Perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Istok, Jonathan D

    2008-07-07

    'Bioimmobilization' of redox-sensitive metals and radionuclides is being investigated as a way to remediate contaminated groundwater and sediments. In this approach, growth-limiting substrates are added to stimulate the activity of targeted groups of indigenous microorganisms and create conditions favorable for the microbially-mediated precipitation ('bioimmobilization') of targeted contaminants. This project investigated a fundamentally new approach for modeling this process that couples thermodynamic descriptions for microbial growth with associated geochemical reactions. In this approach, a synthetic microbial community is defined as a collection of defined microbial groups; each with a growth equation derived from bioenergetic principles. The growth equations and standard-state free energy yields are appended to a thermodynamic database for geochemical reactions and the combined equations are solved simultaneously to predict the effect of added substrates on microbial biomass, community composition, and system geochemistry. This approach, with a single set of thermodynamic parameters (one for each growth equation), was used to predict the results of laboratory and field bioimmobilization experiments at two geochemically diverse research sites. Predicted effects of ethanol or acetate addition on uranium and technetium solubility, major ion geochemistry, mineralogy, microbial biomass and community composition were in general agreement with experimental observations although the available experimental data precluded rigorous model testing. Model simulations provide insight into the long-standing difficulty in transferring experimental results from the laboratory to the field and from one field site to the next, especially if the form, concentration, or delivery of growth substrate is varied from one experiment to the next. Although originally developed for use in better understanding bioimmobilization of uranium and technetium via reductive

  6. Development of dielectric barrier discharge for reducing microbial contamination in pepper (Piper nigrum) and sesame (Sesamum indicum Linn.) powder

    Science.gov (United States)

    Promping, J.; Prakongsil, P.; Picha, R.; Traikool, T.

    2017-09-01

    This research is designed to determine the efficacy of DBD plasma to reduce the microbial contamination of pepper and sesame powder. The AC high voltage power supply was used with voltages of up to 20 kV and the frequency of 5.5 kHz was applied to the DBD. The gap of DBD electrodes was set at 5 mm. In raw initial samples, the total aerobic count of pepper (Piper nigrum) was found at quite a high level at 5.40 × 105 CFU/g. Coliform bacteria was also found in both the sesame (Sesamum indicum Linn.) powder and pepper (Piper nigrum) powder. Both kinds of samples were treated with plasma for 2, 4, 6 and 10 minutes. Results indicated that plasma treatment at 2-10 minutes reduced the total aerobic count of pepper allowed to achieve the acceptable microbial level for spices. The plasma treatment times in this experiment were also effective in reducing faecal coliform bacteria in both pepper and sesame powders (MPN/g <3) as indicated in the standard. Plasma from dielectric barrier charge can reduce Staphylococcus epidermidis in sesame powder which was artificially contaminated with 3.50 × 102 CFU/g resulting in 0.15-0.5 log cycle reductions of microbial load.

  7. Distinct Trajectories of Massive Recent Gene Gains and Losses in Populations of a Microbial Eukaryotic Pathogen.

    Science.gov (United States)

    Hartmann, Fanny E; Croll, Daniel

    2017-11-01

    Differences in gene content are a significant source of variability within species and have an impact on phenotypic traits. However, little is known about the mechanisms responsible for the most recent gene gains and losses. We screened the genomes of 123 worldwide isolates of the major pathogen of wheat Zymoseptoria tritici for robust evidence of gene copy number variation. Based on orthology relationships in three closely related fungi, we identified 599 gene gains and 1,024 gene losses that have not yet reached fixation within the focal species. Our analyses of gene gains and losses segregating in populations showed that gene copy number variation arose preferentially in subtelomeres and in proximity to transposable elements. Recently lost genes were enriched in virulence factors and secondary metabolite gene clusters. In contrast, recently gained genes encoded mostly secreted protein lacking a conserved domain. We analyzed the frequency spectrum at loci segregating a gene presence-absence polymorphism in four worldwide populations. Recent gene losses showed a significant excess in low-frequency variants compared with genome-wide single nucleotide polymorphism, which is indicative of strong negative selection against gene losses. Recent gene gains were either under weak negative selection or neutral. We found evidence for strong divergent selection among populations at individual loci segregating a gene presence-absence polymorphism. Hence, gene gains and losses likely contributed to local adaptation. Our study shows that microbial eukaryotes harbor extensive copy number variation within populations and that functional differences among recently gained and lost genes led to distinct evolutionary trajectories. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  8. VAMPS: a website for visualization and analysis of microbial population structures.

    Science.gov (United States)

    Huse, Susan M; Mark Welch, David B; Voorhis, Andy; Shipunova, Anna; Morrison, Hilary G; Eren, A Murat; Sogin, Mitchell L

    2014-02-05

    The advent of next-generation DNA sequencing platforms has revolutionized molecular microbial ecology by making the detailed analysis of complex communities over time and space a tractable research pursuit for small research groups. However, the ability to generate 10⁵-10⁸ reads with relative ease brings with it many downstream complications. Beyond the computational resources and skills needed to process and analyze data, it is difficult to compare datasets in an intuitive and interactive manner that leads to hypothesis generation and testing. We developed the free web service VAMPS (Visualization and Analysis of Microbial Population Structures, http://vamps.mbl.edu) to address these challenges and to facilitate research by individuals or collaborating groups working on projects with large-scale sequencing data. Users can upload marker gene sequences and associated metadata; reads are quality filtered and assigned to both taxonomic structures and to taxonomy-independent clusters. A simple point-and-click interface allows users to select for analysis any combination of their own or their collaborators' private data and data from public projects, filter these by their choice of taxonomic and/or abundance criteria, and then explore these data using a wide range of analytic methods and visualizations. Each result is extensively hyperlinked to other analysis and visualization options, promoting data exploration and leading to a greater understanding of data relationships. VAMPS allows researchers using marker gene sequence data to analyze the diversity of microbial communities and the relationships between communities, to explore these analyses in an intuitive visual context, and to download data, results, and images for publication. VAMPS obviates the need for individual research groups to make the considerable investment in computational infrastructure and bioinformatic support otherwise necessary to process, analyze, and interpret massive amounts of next

  9. Genome-centric metatranscriptomes and ecological roles of the active microbial populations during cellulosic biomass anaerobic digestion.

    Science.gov (United States)

    Jia, Yangyang; Ng, Siu-Kin; Lu, Hongyuan; Cai, Mingwei; Lee, Patrick K H

    2018-01-01

    Although anaerobic digestion for biogas production is used worldwide in treatment processes to recover energy from carbon-rich waste such as cellulosic biomass, the activities and interactions among the microbial populations that perform anaerobic digestion deserve further investigations, especially at the population genome level. To understand the cellulosic biomass-degrading potentials in two full-scale digesters, this study examined five methanogenic enrichment cultures derived from the digesters that anaerobically digested cellulose or xylan for more than 2 years under 35 or 55 °C conditions. Metagenomics and metatranscriptomics were used to capture the active microbial populations in each enrichment culture and reconstruct their meta-metabolic network and ecological roles. 107 population genomes were reconstructed from the five enrichment cultures using a differential coverage binning approach, of which only a subset was highly transcribed in the metatranscriptomes. Phylogenetic and functional convergence of communities by enrichment condition and phase of fermentation was observed for the highly transcribed populations in the metatranscriptomes. In the 35 °C cultures grown on cellulose, Clostridium cellulolyticum -related and Ruminococcus -related bacteria were identified as major hydrolyzers and primary fermenters in the early growth phase, while Clostridium leptum -related bacteria were major secondary fermenters and potential fatty acid scavengers in the late growth phase. While the meta-metabolism and trophic roles of the cultures were similar, the bacterial populations performing each function were distinct between the enrichment conditions. Overall, a population genome-centric view of the meta-metabolism and functional roles of key active players in anaerobic digestion of cellulosic biomass was obtained. This study represents a major step forward towards understanding the microbial functions and interactions at population genome level during the

  10. Assessment of the microbial populations in field and test pit experiments at Elliot Lake, Ontario, Canada

    International Nuclear Information System (INIS)

    Silver, M.; Taylor, J.B.

    1981-01-01

    Enumeration of aerobic and anaerobic heterotrophic (organic carbon-using) bacteria shows the establishment of a microbial population on vegetated tailings. The development of a population of heterotrophic bacteria, 90% of which are obligate aerobes, in the top 5 cm of the tailings is indicative of normal soil formation. The cell concentration decrease is greater than that found in older, well-developed soils. Iron-oxidizing thiobacilli are rarely present in the revegetated tailings, and then only at depths below 40 cm and at cell concentrations less than 100 cells/g. On an adjacent unvegetated portion of the tailings, fewer heterotrophic bacteria are found in the top 5 cm of the tailings. Iron-oxidizing thiobacilli are present uniformly in the top 47 cm. Enumeration of iron-oxidizing bacteria in the effluents of four test pit experiments indicate blockage of the drainage tiles in two experiments. Chemical conditions of the effluents are suitable for the formation of basic ferric precipitates that could cause this blockage

  11. Effect of Portulaca oleracea extracts on growth performance and microbial populations in ceca of broilers.

    Science.gov (United States)

    Zhao, X H; He, X; Yang, X F; Zhong, X H

    2013-05-01

    The aim of this study was to investigate the effects of Portulaca oleracea extracts on growth performance and microbial populations in the ceca of broilers. A total of 120 one-day-old broilers were randomly divided into 3 groups. Portulaca oleracea extracts were added to diets at 0.2 and 0.4% (wt/wt; POL-0.2, POL-0.4), respectively. The control (CON) group was administered with no P. oleracea extract supplementation. Body weight gain and feed conversion ratio were recorded every 2 wk. On d 28 and 42, the cecal contents were collected and assayed for Escherichia coli, Lactobacillus, and Bifidobacterium populations. Additionally, the pH of the ileum and cecum was measured. The results showed that both on d 28 and 42 BW gain of P. oleracea extract supplementation groups was significantly higher, whereas the feed conversion ratio was lower (P < 0.05) compared with CON. On d 28 and 42, significantly (P < 0.05) fewer E. coli were recovered from ceca of broilers provided with the POL-0.2 diet than from broilers provided with the control diet. The quantities of Lactobacillus and Bifidobacterium of POL-0.2 were significantly (P < 0.05) higher than CON. Results showed P. oleracea extracts have no distinct influence on intestinal pH. These data suggest that P. oleracea extract supplementation significantly altered the cecal bacterial community without affecting the intestinal pH.

  12. Porosity and Organic Carbon Controls on Naturally Reduced Zone (NRZ) Formation Creating Microbial ';Hotspots' for Fe, S, and U Cycling in Subsurface Sediments

    Science.gov (United States)

    Jones, M. E.; Janot, N.; Bargar, J.; Fendorf, S. E.

    2013-12-01

    Previous studies have illustrated the importance of Naturally Reduced Zones (NRZs) within saturated sediments for the cycling of metals and redox sensitive contaminants. NRZs can provide a source of reducing equivalents such as reduced organic compounds or hydrogen to stimulate subsurface microbial communities. These NRZ's are typically characterized by low permeability and elevated concentrations of organic carbon and trace metals. However, both the formation of NRZs and their importance to the overall aquifer carbon remineralization is not fully understood. Within NRZs the hydrolysis of particulate organic carbon (POC) and subsequent fermentation of dissolved organic carbon (DOC) to form low molecular weight dissolved organic carbon (LMW-DOC) provides electron donors necessary for the respiration of Fe, S, and in the case of the Rifle aquifer, U. Rates of POC hydrolysis and subsequent fermentation have been poorly constrained and rates in excess and deficit to the rates of subsurface anaerobic respiratory processes have been suggested. In this study, we simulate the development of NRZ sediments in diffusion-limited aggregates to investigate the physical and chemical conditions required for NRZ formation. Effects of sediment porosity and POC loading on Fe, S, and U cycling on molecular and nanoscale are investigated with synchrotron-based Near Edge X-ray Absorption Fine Structure Spectroscopy (NEXAFS). Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and Fourier Transform Infrared spectroscopy (FTIR) are used to characterize the transformations in POC and DOC. Sediment aggregates are inoculated with the natural microbial biota from the Rifle aquifer and population dynamics are monitored by 16S RNA analysis. Overall, establishment of low permeability NRZs within the aquifer stimulate microbial respiration beyond the diffusion-limited zones and can limit the transport of U through a contaminated aquifer. However, the long-term stability of

  13. Efficacy of Denture Cleansers in Reducing Microbial Counts from Removable Partial Dentures: A Short-Term Clinical Evaluation

    OpenAIRE

    Lucena-Ferreira,Silvia Carneiro de; Cavalcanti,Indira Moraes Gomes; Cury,Altair Antoninha Del Bel

    2013-01-01

    This clinical study investigated if daily immersion in denture cleansers reduces microbial counts on removable partial denture's (RPD) biofilm. Twenty-five RPD wearer volunteers were selected and instructed to complement the hygiene of their dentures by immersing them in an enzymatic peroxide-based denture cleanser (Polident® 3 minute) once a day for 3 min for a period of 15 days. The biofilm was collected from RPD surfaces with a swab immediately before (baseline) and after the experimental ...

  14. The nanostructure of microbially-reduced graphene oxide fosters thick and highly-performing electrochemically-active biofilms

    Science.gov (United States)

    Virdis, Bernardino; Dennis, Paul G.

    2017-07-01

    Biofilms of electrochemically-active organisms are used in microbial electrochemical technologies (METs) to catalyze bioreactions otherwise not possible at bare electrodes. At present, however, achievable current outputs are still below levels considered sufficient for economic viability of large-scale METs implementations. Here, we report three-dimensional, self-aggregating biofilm composites comprising of microbial cells embedded with microbially-reduced graphene oxide (rGO) nanoparticles to form a thick macro-porous network with superior electrochemical properties. In the presence of metabolic substrate, these hybrid biofilms are capable of producing up to five times more catalytic current than the control biofilms. Cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy, show that in spite of the increased thickness, the biofilms amended with GO display lower polarization/charge transfer resistance compared to the controls, which we ascribe to the incorporation of rGO into the biofilms, which (1) promotes fast electron transfer, yet conserving a macroporous structure that allows free diffusion of reactants and products, and (2) enhances the interfacial dynamics by allowing a higher load of microbial cells per electrode surface area. These results suggest an easy-to-apply and cost-effective method to produce high-performing electrochemically-active biofilms in situ.

  15. In situ exposure to low herbicide concentrations affects microbial population composition and catabolic gene frequency in an aerobic shallow aquifer

    DEFF Research Database (Denmark)

    de Lipthay, J.R.; Tuxen, Nina; Johnsen, Kaare

    2003-01-01

    and were analyzed for the presence of general microbial populations, Pseudomonas bacteria, and specific phenoxy acid degraders. Both culture-dependent and culture-independent methods were applied. The abundance of microbial phenoxy acid degraders (10(0) to 10(4) g(-1) sediment) was determined by most...... measured by either PCR or plating on selective agar media was higher in sediments subjected to high levels of phenoxy acid. Furthermore, high numbers of CFU compared to direct counting of 4',6-diamidino-2-phenylindole-stained cells in the microscope suggested an increased culturability of the indigenous...

  16. Microbial population analysis of the salivary glands of ticks; a possible strategy for the surveillance of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Yongjin Qiu

    Full Text Available Ticks are one of the most important blood-sucking vectors for infectious microorganisms in humans and animals. When feeding they inject saliva, containing microbes, into the host to facilitate the uptake of blood. An understanding of the microbial populations within their salivary glands would provide a valuable insight when evaluating the vectorial capacity of ticks. Three tick species (Ixodes ovatus, I. persulcatus and Haemaphysalis flava were collected in Shizuoka Prefecture of Japan between 2008 and 2011. Each tick was dissected and the salivary glands removed. Bacterial communities in each salivary gland were characterized by 16S amplicon pyrosequencing using a 454 GS-Junior Next Generation Sequencer. The Ribosomal Database Project (RDP Classifier was used to classify sequence reads at the genus level. The composition of the microbial populations of each tick species were assessed by principal component analysis (PCA using the Metagenomics RAST (MG-RAST metagenomic analysis tool. Rickettsia-specific PCR was used for the characterization of rickettsial species. Almost full length of 16S rDNA was amplified in order to characterize unclassified bacterial sequences obtained in I. persulcatus female samples. The numbers of bacterial genera identified for the tick species were 71 (I. ovatus, 127 (I. persulcatus and 59 (H. flava. Eighteen bacterial genera were commonly detected in all tick species. The predominant bacterial genus observed in all tick species was Coxiella. Spiroplasma was detected in Ixodes, and not in H. flava. PCA revealed that microbial populations in tick salivary glands were different between tick species, indicating that host specificities may play an important role in determining the microbial complement. Four female I. persulcatus samples contained a high abundance of several sequences belonging to Alphaproteobacteria symbionts. This study revealed the microbial populations within the salivary glands of three species of

  17. Reducing assembly complexity of microbial genomes with single-molecule sequencing

    Science.gov (United States)

    Genome assembly algorithms cannot fully reconstruct microbial chromosomes from the DNA reads output by first or second-generation sequencing instruments. Therefore, most genomes are left unfinished due to the significant resources required to manually close gaps left in the draft assemblies. Single-...

  18. Abundance, production and stabilization of microbial biomass under conventional and reduced tillage

    NARCIS (Netherlands)

    Groenigen, van K.J.; Bloem, J.; Baath, E.; Boeckx, P.; Rousk, J.; Bodé, S.; Forristal, P.D.; Jones, M.B.

    2010-01-01

    Soil tillage practices affect the soil microbial community in various ways, with possible consequences for nitrogen (N) losses, plant growth and soil organic carbon (C) sequestration. As microbes affect soil organic matter (SOM) dynamics largely through their activity, their impact may not be

  19. Assessing the effects of iron enrichment across holobiont compartments reveals reduced microbial nitrogen fixation in the Red Sea coral Pocillopora verrucosa

    KAUST Repository

    Radecker, Nils; Pogoreutz, Claudia; Ziegler, Maren; Ashok, Ananya; Barreto, Marcelle M.; Chaidez, Veronica; Grupstra, Carsten G. B.; Ng, Yi Mei; Perna, Gabriela; Aranda, Manuel; Voolstra, Christian R.

    2017-01-01

    The productivity of coral reefs in oligotrophic tropical waters is sustained by an efficient uptake and recycling of nutrients. In reef-building corals, the engineers of these ecosystems, this nutrient recycling is facilitated by a constant exchange of nutrients between the animal host and endosymbiotic photosynthetic dinoflagellates (zooxanthellae), bacteria, and other microbes. Due to the complex interactions in this so-called coral holobiont, it has proven difficult to understand the environmental limitations of productivity in corals. Among others, the micronutrient iron has been proposed to limit primary productivity due to its essential role in photosynthesis and bacterial processes. Here, we tested the effect of iron enrichment on the physiology of the coral Pocillopora verrucosa from the central Red Sea during a 12-day experiment. Contrary to previous reports, we did not see an increase in zooxanthellae population density or gross photosynthesis. Conversely, respiration rates were significantly increased, and microbial nitrogen fixation was significantly decreased. Taken together, our data suggest that iron is not a limiting factor of primary productivity in Red Sea corals. Rather, increased metabolic demands in response to iron enrichment, as evidenced by increased respiration rates, may reduce carbon (i.e., energy) availability in the coral holobiont, resulting in reduced microbial nitrogen fixation. This decrease in nitrogen supply in turn may exacerbate the limitation of other nutrients, creating a negative feedback loop. Thereby, our results highlight that the effects of iron enrichment appear to be strongly dependent on local environmental conditions and ultimately may depend on the availability of other nutrients.

  20. Assessing the effects of iron enrichment across holobiont compartments reveals reduced microbial nitrogen fixation in the Red Sea coral Pocillopora verrucosa

    KAUST Repository

    Radecker, Nils

    2017-07-31

    The productivity of coral reefs in oligotrophic tropical waters is sustained by an efficient uptake and recycling of nutrients. In reef-building corals, the engineers of these ecosystems, this nutrient recycling is facilitated by a constant exchange of nutrients between the animal host and endosymbiotic photosynthetic dinoflagellates (zooxanthellae), bacteria, and other microbes. Due to the complex interactions in this so-called coral holobiont, it has proven difficult to understand the environmental limitations of productivity in corals. Among others, the micronutrient iron has been proposed to limit primary productivity due to its essential role in photosynthesis and bacterial processes. Here, we tested the effect of iron enrichment on the physiology of the coral Pocillopora verrucosa from the central Red Sea during a 12-day experiment. Contrary to previous reports, we did not see an increase in zooxanthellae population density or gross photosynthesis. Conversely, respiration rates were significantly increased, and microbial nitrogen fixation was significantly decreased. Taken together, our data suggest that iron is not a limiting factor of primary productivity in Red Sea corals. Rather, increased metabolic demands in response to iron enrichment, as evidenced by increased respiration rates, may reduce carbon (i.e., energy) availability in the coral holobiont, resulting in reduced microbial nitrogen fixation. This decrease in nitrogen supply in turn may exacerbate the limitation of other nutrients, creating a negative feedback loop. Thereby, our results highlight that the effects of iron enrichment appear to be strongly dependent on local environmental conditions and ultimately may depend on the availability of other nutrients.

  1. Reducing nitrogen crossover in microbial reverse-electrodialysis cells by using adjacent anion exchange membranes and anion exchange resin

    KAUST Repository

    Wallack, Maxwell J.; Geise, Geoffrey M.; Hatzell, Marta C.; Hickner, Michael A.; Logan, Bruce E.

    2015-01-01

    Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Waste heat can be used to distill ammonium bicarbonate into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to avoid ammonia loses, and foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω cm2 (1 AEM) to 295 Ω cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω cm2, no resin; 166 Ω cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.

  2. Microbial impact on metallic corrosion processes: case of iron reducing bacteria

    International Nuclear Information System (INIS)

    Esnault, Loic; Jullien, Michel; Libert, Marie; Mustin, Christian

    2010-01-01

    corrosion product alteration, magnetite and hematite mainly (c). For that, an optimised method of H2 measure at weak pressure has been realised by gaseous phase chromatography coupled with a sensitive pressure captor. - H 2 + Fe 3+ magnetite → Fe 2+ solution + 2H + (c) The interest of this study is to determine and to understand the reactivity of one model microbe species, the ferric-reducing bacterium 'Schewanella oneidensis strain MR-1', on a Fe(0) corrosion and these corrosion products (magnetite, hematite mainly) in presence or not of clay minerals (bentonite MX80). The introduction of short-term experiments in the scattered environment (batch) over reactivity Iron-bacteria with or without clay mineral is here studied through a kinetic study of H 2 bio-consumed or product, chemical analysis in solution, and by use a crystallo-chemistry tool (XRD and SEM). The main results are bio-alteration of corrosion products with development of ferri-reducing bacterial community. This microbial alteration entails an increase of aqueous corrosion by consumption of corrosion products (passivation layer). In such condition, corrosion process could be reactivated. (authors)

  3. Understanding the performance of sulfate reducing bacteria based packed bed reactor by growth kinetics study and microbial profiling.

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2016-07-15

    A novel marine waste extract (MWE) as alternative nitrogen source was explored for the growth of sulfate reducing bacteria (SRB). Variation of sulfate and nitrogen (MWE) showed that SRB growth follows an uncompetitive inhibition model. The maximum specific growth rates (μmax) of 0.085 and 0.124 h(-1) and inhibition constants (Ki) of 56 and 4.6 g/L were observed under optimized sulfate and MWE concentrations, respectively. The kinetic data shows that MWE improves the microbial growth by 27%. The packed bed bioreactor (PBR) under optimized sulfate and MWE regime showed sulfate removal efficiency of 62-66% and metals removal efficiency of 66-75% on using mine wastewater. The microbial community analysis using DGGE showed dominance of SRB (87-89%). The study indicated the optimum dosing of sulfate and cheap organic nitrogen to promote the growth of SRB over other bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Solar energy system reduces time taken to inhibit microbial growth in soil

    Energy Technology Data Exchange (ETDEWEB)

    Phitthayarachasak, Thanathep; Thepa, Sirichai; Kongkiattikajorn, Jirasak [Energy Technology Division, School of Energy Environment and Materials, King Mongkut' s University of Technology Thonburi, 126 Prachauthid Road, Tungkru, Bangkok 10140 (Thailand)

    2009-11-15

    This research studied how to reduce the time consumption and to increase and improve the efficiency of the solarization process. The asymmetry compound parabolic concentrator (ACPC) was developed to produce boiling water to be utilized while the solarization process was in operation. This could decrease the time consumed in the solarization process from 4 to 6 weeks to 4 h, with a temperature of approximately 41.25 C at the various depth levels, not exceeding 50 cm. The test to inhibit the growth of Ralstonia solanacearum, the causative agent of wilt in crops leaves, indicated that R. solanacearum was reduced from the total bacterial population of 10.9 x 10{sup 8} colony forming unit/g soil (cfu g{sup -1}) at soil surface to 9.0 x 10{sup 7}, 7.5 x 10{sup 4} and 4.1 x 10{sup 3} cfu g{sup -1} within 1, 2 and 4 h, respectively. (author)

  5. Population structure of microbial communities associated with two deep, anaerobic, alkaline aquifers.

    Science.gov (United States)

    Fry, N K; Fredrickson, J K; Fishbain, S; Wagner, M; Stahl, D A

    1997-04-01

    Microbial communities of two deep (1,270 and 316 m) alkaline (pH 9.94 and 8.05), anaerobic (Eh, -137 and -27 mV) aquifers were characterized by rRNA-based analyses. Both aquifers, the Grande Ronde (GR) and Priest rapids (PR) formations, are located within the Columbia River Basalt Group in south-central Washington, and sulfidogenesis and methanogenesis characterize the GR and PR formations, respectively. RNA was extracted from microorganisms collected from groundwater by ultrafiltration through hollow-fiber membranes and hybridized to taxon-specific oligonucleotide probes. Of the three domains, Bacteria dominated both communities, making up to 92.0 and 64.4% of the total rRNA from the GR and PR formations, respectively. Eucarya comprised 5.7 and 14.4%, and Archaea comprised 1.8% and 2.5%, respectively. The gram-positive target group was found in both aquifers, 11.7% in GR and 7.6% in PR. Two probes were used to target sulfate- and/or metal-reducing bacteria within the delta subclass of Proteobacteria. The Desulfobacter groups was present (0.3%) only in the high-sulfate groundwater (GR). However, comparable hybridization to a probe selective for the desulfovibrios and some metal-reducing bacteria was found in both aquifers, 2.5 and 2.9% from the GR and PR formations, respectively. Selective PCR amplification and sequencing of the desulfovibrio/metal-reducing group revealed a predominance of desulfovibrios in both systems (17 of 20 clones), suggesting that their environmental distribution is not restricted by sulfate availability.

  6. Effects of probiotic supplement ( and on feed efficiency, growth performance, and microbial population of weaning rabbits

    Directory of Open Access Journals (Sweden)

    Thanh Lam Phuoc

    2017-02-01

    Full Text Available Objective This study aimed to investigate the effects of single or/and double strains of probiotic supplement on feed efficiency, growth performance, and microbial population in distal gastrointestinal tract (GIT of weaning rabbits. Methods Sixty-four weaning (28 days old New Zealand White rabbits were randomly distributed into four groups with treatments including: basal diet without probiotic supplement (control or supplemented as follows: 1×106 cfu/g B. subtilis (BS group, 1×107 cfu/g L. acidophilus (LA group, or 0.5×106 cfu/g B. subtilis plus 0.5×107 cfu/g L. acidophilus (BL group. During the research, the male and female rabbits were fed separately. Body weight of the rabbits was recorded at 28, 42, and 70 d of age. Results There was an increase (p<0.05 in body weight gain for the LA group at 42 d. Rabbits fed BL responsed with a greater growth (p<0.05 and better feed conversion ratio (p<0.05 than those fed with no probiotic. Digestibility coefficients of dry matter, organic matter, crude protein, neutral detergent fiber, and gross energy were higher (p<0.05 in LA and BL groups than those in the control group. Male rabbits had higher (p<0.05 Bacilli spp. and Coliformis spp. in the ileum than female rabbits. Rabbits supplemented with BS had greater (p<0.05 numbers of bacilli in all intestinal segments than those receiving no probiotic, whereas intestinal Lactobacilli populations were greater (p<0.001 in the LA and BL diets compared to control. Average intestinal coliform populations were lowest (p<0.05 in the rabbits supplemented with LA as compared to those fed the control and BS. Conclusion Supplementation of L. acidophilus alone or in combination with B. subtilis at a half of dose could enhance number of gut beneficial bacteria populations, nutrient digestibility, cecal fermentation, feed efficiency, and growth performance, but rabbits receiving only B. subtilis alone were not different from the controls without probiotic.

  7. Copper current collectors reduce long-term fouling of air cathodes in microbial fuel cells

    KAUST Repository

    Myung, Jaewook; Yang, Wulin; Saikaly, Pascal; Logan, Bruce E

    2018-01-01

    Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activated carbon and stainless steel (SS) current collectors can result in decreased performance due to cathode fouling. Copper has good antimicrobial properties, and it is more electrically conductive than SS. To demonstrate that a copper current collector could produce a more fouling resistant cathode, MFCs with air cathodes using either SS or copper current collectors were operated using domestic wastewater for 27 weeks. The reduction in biofouling over time was shown by less biofilm formation on the copper cathode surface compared to SS cathodes, due to the antimicrobial properties of copper. Maximum power densities from 17–27 weeks were 440 ± 38 mW/m2 using copper and 370 ± 21 mW/m2 using SS cathodes. The main difference in the microbial community was a nitrifying community on the SS cathodes, which was not present on the copper cathodes.

  8. Copper current collectors reduce long-term fouling of air cathodes in microbial fuel cells

    KAUST Repository

    Myung, Jaewook

    2018-02-05

    Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activated carbon and stainless steel (SS) current collectors can result in decreased performance due to cathode fouling. Copper has good antimicrobial properties, and it is more electrically conductive than SS. To demonstrate that a copper current collector could produce a more fouling resistant cathode, MFCs with air cathodes using either SS or copper current collectors were operated using domestic wastewater for 27 weeks. The reduction in biofouling over time was shown by less biofilm formation on the copper cathode surface compared to SS cathodes, due to the antimicrobial properties of copper. Maximum power densities from 17–27 weeks were 440 ± 38 mW/m2 using copper and 370 ± 21 mW/m2 using SS cathodes. The main difference in the microbial community was a nitrifying community on the SS cathodes, which was not present on the copper cathodes.

  9. Electricity generation from cattle dung using microbial fuel cell technology during anaerobic acidogenesis and the development of microbial populations.

    Science.gov (United States)

    Zhao, Guang; Ma, Fang; Wei, Li; Chua, Hong; Chang, Chein-Chi; Zhang, Xiao-Jun

    2012-09-01

    A microbial fuel cell (MFC) was constructed to investigate the possible generation of electricity using cattle dung as a substrate. After 30 days of operation, stable electricity was generated, and the maximum volumetric power density was 0.220 W/m(3). The total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of the MFC reached 73.9±1.8% and 2.79±0.6%, respectively, after 120 days of operation. Acetate was the main metabolite in the anolyte, and other volatile fatty acids (VFAs) (propionate and butyrate) were present in minor amounts. The PCR-DGGE analysis indicated that the following five groups of microbes were present: Proteobacteria, Bacteroides, Chloroflexi, Actinobacteria and Firmicutes. Proteobacteria and Firmicutes were the dominant phyla in the sample; specifically, 36.3% and 24.2% of the sequences obtained were Proteobacteria and Firmicutes, respectively. Clostridium sp., Pseudomonas luteola and Ochrobactrum pseudogrignonense were the most dominant groups during the electricity generation process. The diversity of archaea dramatically decreased after 20 days of operation. The detected archaea were hydrogenotrophic methanogens, and the Methanobacterium genus disappeared during the periods of stable electricity generation via acidogenesis. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Electricity Recovery from Municipal Sewage Wastewater Using a Hydrogel Complex Composed of Microbially Reduced Graphene Oxide and Sludge

    Directory of Open Access Journals (Sweden)

    Naoko Yoshida

    2016-08-01

    Full Text Available Graphene oxide (GO has recently been shown to be an excellent anode substrate for exoelectrogens. This study demonstrates the applicability of GO in recovering electricity from sewage wastewater. Anaerobic incubation of sludge with GO formed a hydrogel complex that embeds microbial cells via π-π stacking of microbially reduced GO. The rGO complex was electrically conductive (23 mS·cm−1 and immediately produced electricity in sewage wastewater under polarization at +200 mV vs. Ag/AgCl. Higher and more stable production of electricity was observed with rGO complexes (179–310 μA·cm−3 than with graphite felt (GF; 79–95 μA·cm−3. Electrochemical analyses revealed that this finding was attributable to the greater capacitance and smaller internal resistance of the rGO complex. Microbial community analysis showed abundances of Geobacter species in both rGO and GF complexes, whereas more diverse candidate exoelectrogens in the Desulfarculaceae family and Geothrix genus were particularly prominent in the rGO complex.

  11. Effect of Rhodophyta extracts on in vitro ruminal fermentation characteristics, methanogenesis and microbial populations.

    Science.gov (United States)

    Lee, Shin Ja; Shin, Nyeon Hak; Jeong, Jin Suk; Kim, Eun Tae; Lee, Su Kyoung; Lee, Sung Sill

    2018-01-01

    Due to the threat of global warming, the livestock industry is increasingly interested in exploring how feed additives may reduce anthropogenic greenhouse gas emissions, especially from ruminants. This study investigated the effect of Rhodophyta supplemented bovine diets on in vitro rumen fermentation and rumen microbial diversity. Cannulated Holstein cows were used as rumen fluid donors. Rumen fluid:buffer (1:2; 15 mL) solution was incubated for up to 72 h in six treatments: a control (timothy hay only), along with substrates containing 5% extracts from five Rhodophyta species ( Grateloupia lanceolata [Okamura] Kawaguchi, Hypnea japonica Tanaka, Pterocladia capillacea [Gmelin] Bornet, Chondria crassicaulis Harvey, or Gelidium amansii [Lam.] Lamouroux). Compared with control, Rhodophyta extracts increased cumulative gas production after 24 and 72 h (p = 0.0297 and p = 0.0047). The extracts reduced methane emission at 12 and 24 h (p<0.05). In particular, real-time polymerase chain reaction analysis indicated that at 24 h, ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens decreased at 24 h (p = 0.0002, p<0.0001, and p<0.0001), while Fibrobacter succinogenes ( F. succinogenes ) increased (p = 0.0004). Additionally, Rhodophyta extracts improved acetate concentration at 12 and 24 h (p = 0.0766 and p = 0.0132), as well as acetate/propionate (A/P) ratio at 6 and 12 h (p = 0.0106 and p = 0.0278). Rhodophyta extracts are a viable additive that can improve ruminant growth performance (higher total gas production, lower A/P ratio) and methane abatement (less ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens and more F. succinogenes .

  12. Effect of Rhodophyta extracts on ruminal fermentation characteristics, methanogenesis and microbial populations

    Directory of Open Access Journals (Sweden)

    Shin Ja Lee

    2018-01-01

    Full Text Available Objective Due to the threat of global warming, the livestock industry is increasingly interested in exploring how feed additives may reduce anthropogenic greenhouse gas emissions, especially from ruminants. This study investigated the effect of Rhodophyta supplemented bovine diets on in vitro rumen fermentation and rumen microbial diversity. Methods Cannulated Holstein cows were used as rumen fluid donors. Rumen fluid:buffer (1:2; 15 mL solution was incubated for up to 72 h in six treatments: a control (timothy hay only, along with substrates containing 5% extracts from five Rhodophyta species (Grateloupia lanceolata [Okamura] Kawaguchi, Hypnea japonica Tanaka, Pterocladia capillacea [Gmelin] Bornet, Chondria crassicaulis Harvey, or Gelidium amansii [Lam.] Lamouroux. Results Compared with control, Rhodophyta extracts increased cumulative gas production after 24 and 72 h (p = 0.0297 and p = 0.0047. The extracts reduced methane emission at 12 and 24 h (p<0.05. In particular, real-time polymerase chain reaction analysis indicated that at 24 h, ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens decreased at 24 h (p = 0.0002, p<0.0001, and p<0.0001, while Fibrobacter succinogenes (F. succinogenes increased (p = 0.0004. Additionally, Rhodophyta extracts improved acetate concentration at 12 and 24 h (p = 0.0766 and p = 0.0132, as well as acetate/propionate (A/P ratio at 6 and 12 h (p = 0.0106 and p = 0.0278. Conclusion Rhodophyta extracts are a viable additive that can improve ruminant growth performance (higher total gas production, lower A/P ratio and methane abatement (less ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens and more F. succinogenes.

  13. Microbial metagenomes from three aquifers in the Fennoscandian shield terrestrial deep biosphere reveal metabolic partitioning among populations.

    Science.gov (United States)

    Wu, Xiaofen; Holmfeldt, Karin; Hubalek, Valerie; Lundin, Daniel; Åström, Mats; Bertilsson, Stefan; Dopson, Mark

    2016-05-01

    Microorganisms in the terrestrial deep biosphere host up to 20% of the earth's biomass and are suggested to be sustained by the gases hydrogen and carbon dioxide. A metagenome analysis of three deep subsurface water types of contrasting age (from 86% coverage. The populations were dominated by Proteobacteria, Candidate divisions, unclassified archaea and unclassified bacteria. The estimated genome sizes of the biosphere. The data were finally used to create a combined metabolic model of the deep terrestrial biosphere microbial community.

  14. Population segmentation: an approach to reducing childhood obesity inequalities.

    Science.gov (United States)

    Mahmood, Hashum; Lowe, Susan

    2017-05-01

    The aims of this study are threefold: (1) to investigate the relationship between socio-economic status (inequality) and childhood obesity prevalence within Birmingham local authority, (2) to identify any change in childhood obesity prevalence between deprivation quintiles and (3) to analyse individualised Birmingham National Child Measurement Programme (NCMP) data using a population segmentation tool to better inform obesity prevention strategies. Data from the NCMP for Birmingham (2010/2011 and 2014/2015) were analysed using the deprivation scores from the Income Domain Affecting Children Index (IDACI 2010). The percentage of children with excess weight was calculated for each local deprivation quintile. Population segmentation was carried out using the Experian's Mosaic Public Sector 6 (MPS6) segmentation tool. Childhood obesity levels have remained static at the national and Birmingham level. For Year 6 pupils, obesity levels have increased in the most deprived deprivation quintiles for boys and girls. The most affluent quintile shows a decreasing trend of obesity prevalence for boys and girls in both year groups. For the middle quintiles, the results show fluctuating trends. This research highlighted the link in Birmingham between obesity and socio-economic factors with the gap increasing between deprivation quintiles. Obesity is a complex problem that cannot simply be addressed through targeting most deprived populations, rather through a range of effective interventions tailored for the various population segments that reside within communities. Using population segmentation enables a more nuanced understanding of the potential barriers and levers within populations on their readiness for change. The segmentation of childhood obesity data will allow utilisation of social marketing methodology that will facilitate identification of suitable methods for interventions and motivate individuals to sustain behavioural change. Sequentially, it will also inform

  15. Combined treatment with mild heat, manothermosonication and pulsed electric fields reduces microbial growth in milk

    OpenAIRE

    Halpin, R. M.; Cregenzan-Alberti, O.; Whyte, P.; Lyng, J. G.; Noci, F.

    2013-01-01

    In recent years, there has been considerable interest in non-thermal milk processing. The objective of the present study was to assess the efficacy of two non-thermal technologies (manothermosonication; MTS, and pulsed electric fields; PEF) in comparison to thermal pasteurisation, by assessing the microbial levels of each of these milk samples post-processing. Homogenised milk was subjected to MTS (frequency; 20 kHz, amplitude; 27.9 μm, pressure; 225 kPa) at two temperatures (37 °C or 55 °C),...

  16. [Immunomodulators of microbial origin enhance cytotoxicity of human mononuclear leukocytes and reduce metastatic progression of Lewis lung carcinoma in mice].

    Science.gov (United States)

    Akhmatova, N K; Semenova, I B; Donenko, F V; Kiselevskiĭ, M V; Kurbatova, E A; Egorova, N B

    2006-01-01

    Effect of immunomodulators for microbial origin on innate immunity and antitumor system was continued to study. Immunomodificator Immunovac VP-4, purified staphylococcal toxoid and glucosaminyl muramyl dipeptide (GMDP) equally enhanced cytotoxicity of mononuclear leukocytes of peripheral blood of healthy donors. Index of cytotoxicity was 2.78, 2.77 and 2.70 respectively. Reduced metastatic progression of Lewis lung carcinoma in mice was observed after Immunovac VP-4 and GMDP administration. Effectiveness was seen when preparations administered according to schedules including their administration before implantation of the tumor. If preparations were administered number of metastases reduced in 4.4-5.6 times and size of metastases reduced in 7-10 times. Interplay between antitumor activity of studied immunomodulators and cytotoxic activity of NK-cells, which are base effectors of antitumor immune response, are discussed.

  17. Evolution with a seed bank: The population genetic consequences of microbial dormancy.

    Science.gov (United States)

    Shoemaker, William R; Lennon, Jay T

    2018-01-01

    Dormancy is a bet-hedging strategy that allows organisms to persist through conditions that are suboptimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long-term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence the evolutionary dynamics of microorganisms as well as other taxa.

  18. Analysis of rumen microbial populations in lactating dairy cattle fed diets varying in carbohydrate profiles and Saccharomyces cerevisiae fermentation product.

    Science.gov (United States)

    Mullins, C R; Mamedova, L K; Carpenter, A J; Ying, Y; Allen, M S; Yoon, I; Bradford, B J

    2013-09-01

    The rumen microbial ecosystem is a critical factor that links diets to bovine physiology and productivity; however, information about dietary effects on microbial populations has generally been limited to small numbers of samples and qualitative assessment. To assess whether consistent shifts in microbial populations occur in response to common dietary manipulations in dairy cattle, samples of rumen contents were collected from 2 studies for analysis by quantitative real-time PCR (qPCR). In one study, lactating Holstein cows (n=8) were fed diets in which a nonforage fiber source replaced an increasing proportion of forages and concentrates in a 4×4 Latin square design, and samples of ruminal digesta were collected at 9-h intervals over 3 d at the end of each period. In the second study, lactating Holstein cows (n=15) were fed diets with or without the inclusion of a Saccharomyces cerevisiae fermentation product (SCFP) in a crossover design. In this study, rumen liquid and solid samples were collected during total rumen evacuations before and after feeding in a 42-h period. In total, 146 samples of ruminal digesta were used for microbial DNA isolation and analysis by qPCR. Validated primer sets were used to quantify total bacterial and anaerobic fungal populations as well as 12 well-studied bacterial taxa. The relative abundance of the target populations was similar to those previously reported. No significant treatment effects were observed for any target population. A significant interaction of treatment and dry matter intake was observed, however, for the abundance of Eubacterium ruminantium. Increasing dry matter intake was associated with a quadratic decrease in E. ruminantium populations in control animals but with a quadratic increase in E.ruminantium populations in cows fed SCFP. Analysis of sample time effects revealed that Fibrobacter succinogenes and fungal populations were more abundant postfeeding, whereas Ruminococcus albus tended to be more abundant

  19. Clozapine in Reducing Aggression and Violence in Forensic Populations.

    Science.gov (United States)

    Patchan, Kathleen; Vyas, Gopal; Hackman, Ann L; Mackowick, Marie; Richardson, Charles M; Love, Raymond C; Wonodi, Ikwunga; Sayer, MacKenzie A; Glassman, Matthew; Feldman, Stephanie; Kelly, Deanna L

    2018-03-01

    Popular media often portray people with a mental illness as being aggressive, violent, and incarcerated as a result of their behavior. Despite exaggeration in the media, risks for some aggressive behaviors are in fact higher in individuals with schizophrenia. This is often the case with influence of comorbid substance use disorders. It is essential that mental health professionals are aware of treatments that may help with attenuating and treating behaviors that contribute to violence, aggression and incarceration. This paper reviews violence and incarceration in individuals with schizophrenia as well as recommendations, guidelines and benefits for the use of clozapine in this population. Clozapine remains one of the most underutilized evidence-based medications available in the psychiatric arena in the United States. It is a viable and recommended option in the forensic population and it may be helpful on the path to recovery as well as bring substantial savings to the criminal justice system.

  20. Reducing methane emissions and the methanogen population in the rumen of Tibetan sheep by dietary supplementation with coconut oil.

    Science.gov (United States)

    Ding, Xuezhi; Long, Ruijun; Zhang, Qian; Huang, Xiaodan; Guo, Xusheng; Mi, Jiandui

    2012-10-01

    The objective was to evaluate the effect of dietary coconut oil on methane (CH(4)) emissions and the microbial community in Tibetan sheep. Twelve animals were assigned to receive either a control diet (oaten hay) or a mixture diet containing concentrate (maize meal), in which coconut oil was supplemented at 12 g/day or not for a period of 4 weeks. CH(4) emissions were measured by using the 'tunnel' technique, and microbial communities were examined using quantitative real-time PCR. Daily CH(4) production for the control and forage-to-concentrate ratio of 6:4 was 17.8 and 15.3 g, respectively. Coconut oil was particularly effective at reducing CH(4) emissions from Tibetan sheep. The inclusion of coconut oil for the control decreased CH(4) production (in grams per day) by 61.2%. In addition, there was a positive correlation between the number of methanogens and the daily CH(4) production (R = 0.95, P coconut oil supplemented at 12 g/day decreases the number of methanogens by 77% and a decreases in the ruminal fungal population (85-95%) and Fibrobacter succinogenes (50-98%) but an increase in Ruminococcus flavefaciens (25-70%). The results from our experiment suggest that adding coconut oil to the diet can reduce CH(4) emissions in Tibetan sheep and that these reductions persist for at least the 4-week feeding period.

  1. Reduced neonatal regulatory T cell response to microbial stimuli associates with subsequent eczema in high-risk infants.

    Science.gov (United States)

    Ismail, Intan H; Boyle, Robert J; Mah, Li-Jeen; Licciardi, Paul V; Tang, Mimi L K

    2014-11-01

    Regulatory T cells (Treg) play an essential role in early immune programming and shaping the immune response towards a pro-allergic or tolerant state. We evaluated cord blood Treg and cytokine responses to microbial and non-microbial stimuli in infants at high risk of allergic disease and their associations with development of allergic disease in the first year. Cord blood mononuclear cells from 72 neonates were cultured with toll-like receptors (TLR2) ligands: lipoteichoic acid (LTA) and heat-killed Lactobacillus rhamnosus GG (HKL); TLR4 ligand: lipopolysaccharide (LPS); ovalbumin (OVA); anti-CD3; or media for 48 h. Treg numbers and Treg cytokines were assessed in relation to allergic disease outcomes during the first year of life (eczema and atopic sensitization). Infants with eczema (n = 24) had reduced percentages of FoxP3(hi)CD25(hi) Treg in LTA (p = 0.01, adj p = 0.005) and HKL (p = 0.04, adj p = 0.02) stimulated cultures as well as reduced IL-10 (p = 0.01) production following HKL stimulation compared to those without eczema (n = 48). No differences in Treg or cytokine responses to LPS, OVA or anti-CD3 were seen. Infants who developed sensitization had lower percentages of Treg following TLR2 stimulation (but not other stimuli) compared to non-sensitized infants. High-risk children who develop allergic disease in the first year of life have deficient Treg responses to microbial stimuli but not allergen from the time of birth, which may contribute to failure of immune tolerance development in infancy. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Effects of coconut and fish oils on ruminal methanogenesis, fermentation, and abundance and diversity of microbial populations in vitro.

    Science.gov (United States)

    Patra, A K; Yu, Z

    2013-03-01

    Coconut (CO) and fish (FO) oils were previously shown to inhibit rumen methanogenesis and biohydrogenation, which mitigates methane emission and helps improve beneficial fatty acids in meat and milk. This study aimed at investigating the comparative effects of CO and FO on the methanogenesis, fermentation, and microbial abundances and diversity in vitro rumen cultures containing different doses (0, 3.1, and 6.2 mL/L) of each oil and 400mg feed substrate using rumen fluid from lactating dairy cows as inocula. Increasing doses of CO and FO quadratically decreased concentrations of methane, but hydrogen concentrations were only increased quadratically by CO. Both oils linearly decreased dry matter and neutral detergent fiber digestibility of feeds but did not affect the concentration of total volatile fatty acids. However, CO reduced acetate percentage and acetate to propionate ratio and increased the percentages of propionate and butyrate to a greater extent than FO. Ammonia concentration was greater for CO than FO. As determined by quantitative real-time PCR, FO had greater inhibition to methanogens than CO, but the opposite was true for protozoal, Ruminococcus flavefaciens, and Fibrobacter succinogenes. Ruminococcus albus was not affected by either oil. Denaturing gradient gel electrophoresis (DGGE) profiles revealed that bacterial and archaeal community composition were changed differently by oil type. Based on Pareto-Lorenz evenness curve analysis of the DGGE profiles, CO noticeably changed the functional organization of archaea compared with FO. In conclusion, although both CO and FO decreased methane concentrations to a similar extent, the mode of reduction and the effect on abundances and diversity of archaeal and bacterial populations differed between the oils. Thus, the use of combination of CO and FO at a low dose may additively lower methanogenesis in the rumen while having little adverse effect on rumen fermentation. Copyright © 2013 American Dairy

  3. Dietary fat sources affect feed intake, digestibility, rumen microbial populations, energy partition and methane emissions in different beef cattle genotypes.

    Science.gov (United States)

    Kaewpila, C; Sommart, K; Mitsumori, M

    2018-03-20

    The mitigation of enteric methane emission in beef cattle production is important for reducing feed energy loss and increasing environmental sustainability. The main objective of this study was to evaluate the effect of different oilseeds included in fermented total mixed rations (whole soyabean seed (SBS, control), whole kapok seed (KPS) and cracked oil palm fruit (OPF)) on feed intake, digestibility, rumen microbial populations, energy partition and methane emissions in different cattle genotypes (Charolais crossbred v. Japanese Black crossbred). Three Charolais crossbred and three Japanese Black crossbred bulls were studied in a replicated 3×3 Latin square experimental design; genotypes were analysed in separate squares including three periods of 21 days each and three dietary oilseed treatments fed ad libitum. The cattle were placed in a metabolic cage equipped with a ventilated head box respiration system for evaluating digestibility and energy balance. As compared with Charolais crossbred individuals, Japanese Black crossbred bulls showed consistently lower dry matter intake (15.5%, P0.05) or diet (P>0.05) under the experimental conditions and ranged from 5.8% to 6.0% of gross energy intake. This value is lower than that reported by the Intergovernmental Panel on Climate Change (6.5%) for cattle fed with low-quality crop residues or by-products. Thus, our results imply that the Japanese Black crossbred cattle consume less feed and emits less enteric methane than the Charolais crossbred does, mainly owing to its lower ME requirement for maintenance. The OPF diet could be used to replace SBS for high beef production, although further studies are required to evaluate their application across a wide range of beef production systems.

  4. Importance of using gamma rays to reduce microbial content in heavy cream

    International Nuclear Information System (INIS)

    Abed, H. A.; Aldurrah, O. A. A.; Aldarwash, A. K.

    2012-12-01

    The study aimed to investigate the effect of gamma rays on the pathogenic microorganisms that cause spoilage to the heavy cream and extend its storability period. The heavy cream samples were exposed to 0, 1 and 3 kGy and stored at 4 O C for 1, 10,20 and 30 days. The following microbial tests were carried out for evaluation (Total Bacterial Count, Presence Colonic Bacteria, Fungi and Yeast, Proteolytic Bacteria, and Lipolytic Bacteria). The result revealed that the dose 3 kGy was the best dose could used to control all type of the pathogenic microorganisms tested. Furthermore, the results of the sensory acceptability testes showed that all sensory characteristics of the heavy cream were not affected in comparison with that of the control after one day of storage. (Author)

  5. Effects of operational shocks on key microbial populations for biogas production in UASB (Upflow Anaerobic Sludge Blanket) reactors

    International Nuclear Information System (INIS)

    Couras, C.S.; Louros, V.L.; Grilo, A.M.; Leitão, J.H.; Capela, M.I.; Arroja, L.M.; Nadais, M.H.

    2014-01-01

    This work compares the overall performance and biogas production of continuous and intermittent UASB (Upflow Anaerobic Sludge Blanket) reactors treating dairy wastewater and subjected to fat, hydraulic and temperature shocks. The systems were monitored for methane production, effluent concentration, volatile fatty acids, and microbial populations of the Eubacteria, Archaea and Syntrophomonadaceae groups. This last microbial group has been reported in literature as being determinant for the degradation of fatty substrates present in the wastewater and subsequent biogas production. Results show that both continuous and intermittent systems supported the applied shocks. However, the intermittent systems exhibited better performance than the continuous systems in biogas production and physical-chemical parameters. Syntrophomonadaceae microbial group was present in the intermittent systems, but was not detected in the biomass from the continuous systems. Hydraulic and temperature shocks, but not the fat shock, caused severe losses in the relative abundance of the Syntrophomonadaceae group in intermittent systems, leading to undetectable levels during the temperature shock. The severity of the effects of the applied shocks on the key microbial group Syntrophomonadaceae, were classified as: fats < hydraulic < temperature. Results from a full-scale anaerobic reactor confirm the effect of intermittent operation on the presence of Syntrophomonadaceae and the effect on reactor performance. - Highlights: • We compared intermittent and continuous UASB reactors upon operational shocks. • Syntrophomonadaceae key microbial group for maximizing biogas was quantified by FISH. • Syntrophomonadaceae is present in intermittent but not in continuous UASB reactors. • Syntrophomonadaceae abundance increases with fat shock in intermittent UASB reactor. • Syntrophomonadaceae abundance decreases with hydraulic or temperature shock

  6. Microbial population responses in three stratified Antarctic meltwater ponds during the autumn freeze

    DEFF Research Database (Denmark)

    Safi, Karl; Hawes, Ian; Sorrell, Brian Keith

    2012-01-01

    The planktonic microbial communities of three meltwater ponds, located on the McMurdo Ice Shelf, were investigated from the end of January 2008 to early April, during which almost the entire pond volumes froze. The ponds were comprised of an upper mixed layer overlying a salt-stabilized density g...... for increasing heterotrophy within the remaining microbial communities, although all components of the food web eventually decline as the final freeze approaches....... role of autotrophic and heterotrophic microplankton within the ponds. The results showed that microbial groups responded to the onset of winter by declining in abundance, though an exception was the appearance of filamentous cyanobacteria in the water column in March. As freezing progressed, autotrophs...... declined more rapidly than heterotrophs and grazing rates and abundances of mixotrophic and heterotrophic organisms increased. Grazing pressure on bacteria and picophytoplankton also increased, in part explaining their decline over time. The results indicate that stressors imposed during freezing select...

  7. An approach to mitigating soil CO2 emission by biochemically inhibiting cellulolytic microbial populations through mediation via the medicinal herb Isatis indigotica

    Science.gov (United States)

    Wu, Hong-Sheng; Chen, Su-Yun; Li, Ji; Liu, Dong-Yang; Zhou, Ji; Xu, Ya; Shang, Xiao-Xia; Wei, Dong-yang; Yu, Lu-ji; Fang, Xiao-hang; Li, Shun-yi; Wang, Ke-ke

    2017-06-01

    Greenhouse gases (GHGs, particularly carbon dioxide (CO2)) emissions from soil under wheat production are a significant source of agricultural carbon emissions that have not been mitigated effectively. A field experiment and a static incubation study in a lab were conducted to stimulate wheat growth and investigate its potential to reduce CO2 emissions from soil through intercropping with a traditional Chinese medicinal herb called Isatis indigotica. This work was conducted by adding I. indigotica root exudates based on the quantitative real-time PCR (qPCR) analysis of the DNA copy number of the rhizosphere or bulk soil microbial populations. This addition was performed in relation to the CO2 formation by cellulolytic microorganisms (Penicillium oxalicum, fungi and Ruminococcus albus) to elucidate the microbial ecological basis for the molecular mechanism that decreases CO2 emissions from wheat fields using I. indigotica. The results showed that the panicle weight and full grains per panicle measured through intercropping with I. indigotica (NPKWR) increased by 39% and 28.6%, respectively, compared to that of the CK (NPKW). Intercropping with I. indigotica significantly decreased the CO2 emissions from soil under wheat cultivation. Compared with CK, the total CO2 emission flux during the wheat growth period in the I. indigotica (NPKWR) intercropping treatment decreased by 29.26%. The intensity of CO2 emissions per kg of harvested wheat grain declined from 7.53 kg CO2/kg grain in the NPKW (CK) treatment to 5.55 kg CO2/kg grain in the NPKWR treatment. The qPCR analysis showed that the DNA copy number of the microbial populations of cellulolytic microorganisms (P. oxalicum, fungi and R. albus) in the field rhizosphere around I. indigotica or in the bulk soil under laboratory incubation was significantly lower than that of CK. This finding indicated that root exudates from I. indigotica inhibited the activity and number of cellulolytic microbial populations, which led

  8. Microbially induced separation of quartz from hematite using sulfate reducing bacteria.

    Science.gov (United States)

    Prakasan, M R Sabari; Natarajan, K A

    2010-07-01

    Cells and metabolic products of Desulfovibrio desulfuricans were successfully used to separate quartz from hematite through environmentally benign microbially induced flotation. Bacterial metabolic products such as extracellular proteins and polysaccharides were isolated from both unadapted and mineral-adapted bacterial metabolite and their basic characteristics were studied in order to get insight into the changes brought about on bioreagents during adaptation. Interaction between bacterial cells and metabolites with minerals like hematite and quartz brought about significant surface-chemical changes on both the minerals. Quartz was rendered more hydrophobic, while hematite became more hydrophilic after biotreatment. The predominance of bacterial polysaccharides on interacted hematite and of proteins on quartz was responsible for the above surface-chemical changes, as attested through adsorption studies. Surface-chemical changes were also observed on bacterial cells after adaptation to the above minerals. Selective separation of quartz from hematite was achieved through interaction with quartz-adapted bacterial cells and metabolite. Mineral-specific proteins secreted by quartz-adapted cells were responsible for conferment of hydrophobicity on quartz resulting in enhanced separation from hematite through flotation. 2010 Elsevier B.V. All rights reserved.

  9. Microbial population heterogeneity versus bioreactor heterogeneity: evaluation of Redox Sensor Green as an exogenous metabolic biosensor

    DEFF Research Database (Denmark)

    Baert, Jonathan; Delepierre, Anissa; Telek, Samuel

    2016-01-01

    Microbial heterogeneity in metabolic performances has attracted a lot of attention, considering its potential impact on industrial bioprocesses. However, little is known about the impact of extracellular perturbations (i.e. bioreactor heterogeneity) on cell-to-cell variability in metabolic...

  10. In Silico Gene-Level Evolution Explains Microbial Population Diversity through Differential Gene Mobility

    NARCIS (Netherlands)

    van Dijk, Bram; Hogeweg, P.

    2016-01-01

    Microbial communities can show astonishing ecological and phylogenetic diversity. What is the role of pervasive horizontal gene transfer (HGT) in shaping this diversity in the presence of clonally expanding "killer strains"? Does HGT of antibiotic production and resistance genes erase phylogenetic

  11. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  12. Shifts in the Microbial Population in Relation to in situ Caries Progression

    NARCIS (Netherlands)

    Thomas, R. Z.; Zijnge, V.; Cicek, A.; de Soet, J. J.; Harmsen, H. J. M.; Huysmans, M. C. D. N. J. M.

    2012-01-01

    The shift in microbial diversity from young to mature plaque, related to caries activity on sound and restored surfaces, was studied using denaturing gradient gel electrophoresis. During a 20-week in situ study on caries progression 8 subjects wearing restored and unrestored dentin and enamel

  13. Shifts in the microbial population in relation to in situ caries progression

    NARCIS (Netherlands)

    Thomas, R.Z.; Zijnge, V.; Ciçek, A.; de Soet, J.J.; Harmsen, H.J.M.; Huysmans, M.C.D.N.J.M.

    2012-01-01

    The shift in microbial diversity from young to mature plaque, related to caries activity on sound and restored surfaces, was studied using denaturing gradient gel electrophoresis. During a 20-week in situ study on caries progression 8 subjects wearing restored and unrestored dentin and enamel

  14. Environmental Impact of Tributyltin-Resistant Marine Bacteria in the Indigenous Microbial Population of Tributyltin-Polluted Surface Sediments.

    Science.gov (United States)

    Mimura, Haruo; Yagi, Masahiro; Yoshida, Kazutoshi

    2017-01-01

     We compared the TBT-resistant ability of resting cells prepared from isolates that formed colonies on nutrient agar plates containing 100 µM tributyltin (TBT) chloride, such as Photobacterium sp. TKY1, Halomonas sp. TKY2, and Photobacterium sp. NGY1, with those from taxonomically similar type strains. Photobacterium sp. TKY1 showed the highest ability among those three isolates. The number of surviving Photobacterium sp. TKY1 cells was hardly decreased after 1 h of exposure to 100 µM TBTCl, regardless of the number of resting cells in the range from 10 9.4 to 10 4.2 CFU mL -1 . In such an experimental condition, the maximum number of TBT molecules available to associate with a single cell was estimated to be approximately 6.0 x 10 11.8 . Resting cells prepared from type strains Photobacterium ganghwense JCM 12487 T and P. halotolerans LMG 22194 T , which have 16S rDNA sequences highly homologous with those of Photobacterium sp. TKY1, showed sensitivity to TBT, indicating that TBT-resistant marine bacterial species are not closely related in spite of their taxonomic similarity. We also estimated the impact of TBT-resistant bacterial species to indigenous microbial populations of TBT-polluted surface sediments. The number of surviving TBT-sensitive Vibrio natriegens ATCC 14048 T cells, 10 6.2±0.3 CFU mL -1 , was reduced to 10 4.4±0.4 CFU mL -1 when TBT-resistant Photobacterium sp. TKY1 cells, 10 9.1±0.2 CFU mL -1 , coexisted with 10 9.4±0.2 CFU mL -1 of V. natriegens ATCC 14048 T cells in the presence of 100 µM TBTCl. These results indicate that the toxicity of TBT to TBT-sensitive marine bacterial populations might be enhanced when a TBT-resistant marine bacterial species inhabits TBT-polluted surface sediments.

  15. Process optimization by decoupled control of key microbial populations: distribution of activity and abundance of polyphosphate-accumulating organisms and nitrifying populations in a full-scale IFAS-EBPR plant

    DEFF Research Database (Denmark)

    Onnis-Hayden, Annalisa; Majed, Nehreen; Schramm, Andreas

    2011-01-01

    This study investigated the abundance and distribution of key functional microbial populations and their activities in a full-scale integrated fixed film activated sludgeeenhanced biological phosphorus removal (IFAS-EBPR) process. Polyphosphate accumulating organisms (PAOs) including Accumulibacter...

  16. Corn silage in dairy cow diets to reduce ruminal methanogenesis: effects on the rumen metabolically active microbial communities.

    Science.gov (United States)

    Lettat, A; Hassanat, F; Benchaar, C

    2013-08-01

    Methane produced by the methanogenic Archaea that inhabit the rumen is a potent greenhouse gas and represents an energy loss for the animal. Although several strategies have been proposed to mitigate enteric CH4 production, little is known about the effects of dietary changes on the microbial consortia involved in ruminal methanogenesis. Thus, the current study aimed to examine how the metabolically active microbes are affected when dairy cows were fed diets with increasing proportions of corn silage (CS). For this purpose, 9 ruminally cannulated lactating dairy cows were used in a replicated 3 × 3 Latin square design and fed a total mixed ration (60:40 forage:concentrate ratio on a dry matter basis) with the forage portion being either alfalfa silage (0% CS), corn silage (100% CS), or a 50:50 mixture (50% CS). Enteric CH4 production was determined using respiration chambers and total rumen content was sampled for the determination of fermentation characteristics and molecular biology analyses (cDNA-based length heterogeneity PCR, quantitative PCR). The cDNA-based length heterogeneity PCR targeting active microbes revealed similar bacterial communities in cows fed 0% CS and 50% CS diets, whereas important differences were observed between 0% CS and 100% CS diets, including a reduction in the bacterial richness and diversity in cows fed 100% CS diet. As revealed by quantitative PCR, feeding the 100% CS diet increased the number of total bacteria, Prevotella spp., Archaea, and methanogenic activity, though it reduced protozoal number. Meanwhile, increasing the CS proportion in the diet increased propionate concentration but decreased ruminal pH, CH4 production (L/kg of dry matter intake), and concentrations of acetate and butyrate. Based on these microbial and fermentation changes, and because CH4 production was reduced by feeding 100% CS diet, this study shows that the use of cDNA-based quantitative PCR to estimate archaeal growth and activity is not reliable

  17. Bioaugmentation of anaerobic sludge digestion with iron-reducing bacteria: process and microbial responses to variations in hydraulic retention time.

    Science.gov (United States)

    Baek, Gahyun; Kim, Jaai; Shin, Seung Gu; Lee, Changsoo

    2016-01-01

    Although anaerobic digestion (AD) is a widely used option to manage waste activated sludge (WAS), there are some drawbacks related to its slow reaction rate and low energy productivity. This study examined an anaerobic WAS digester, augmented with an iron-reducing microbial consortium, relative to changes in microbial community structure and process performance at decreasing hydraulic retention times (HRTs) of 20 to 10 days. The enhanced methanation performance (approximately 40 % increase in methane yield) by the bioaugmentation was sustained until the HRT was decreased to 12.5 days, under Fe(3+)-rich conditions (ferric oxyhydroxide, 20 mM Fe). Enhanced iron-reducing activity was evidenced by the increased Fe(2+) to total Fe ratio maintained above 50 % during the stable operational phases. A further decrease in HRT to 10 days resulted in a significant performance deterioration, along with a drop in the Fe(2+) to total Fe ratio to bacteria (IRBs) was identified by denaturing gradient gel electrophoresis (DGGE), with Spirochaetaceae- and Thauera-related organisms being dominant members, and clear dominance shifts among them with respect to decrease in HRT were observed. Lowering HRT led to evident shifts in bacterial community structure likely associated with washout of IRBs, leading to decreases in iron respiration activity and AD performance at a lower HRT. The bacterial community structure shifted dynamically over phases, and the community transitions correlated well with the changes in process performance. Overall, the combined biostimulation and bioaugmentation investigated in this study proved effective for enhanced methane recovery from anaerobic WAS digestion, which suggests an interesting potential for high-rate AD.

  18. Reduced fine-scale spatial genetic structure in grazed populations of Dianthus carthusianorum.

    Science.gov (United States)

    Rico, Y; Wagner, H H

    2016-11-01

    Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on rates of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep grazing on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep grazing showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of grazing treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep grazing were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep grazing has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep grazing to importantly reduce genetic structure at local scales within restored plant populations.

  19. Non-tuberculous mycobacteria and microbial populations in drinking water distribution systems

    Directory of Open Access Journals (Sweden)

    Rossella Briancesco

    2010-01-01

    Full Text Available Data on the occurrence of non-tuberculous mycobacteria (NTM, in parallel with those obtained for bacterial indicators and amoebae, are presented with the aim to collect information on the spread of NTM in drinking water distribution systems in Italy. Samples were collected from taps of hospitals and households in Central and Southern Italy. The concentration values obtained for the more traditional microbial parameters complied with the mandatory requirements for drinking water. Conversely, moderate-to-high microbial loads (till 300 CFU/L were observed for the NTM. Positive samples were obtained from 62% of the investigated water samples. Analogous results were observed for amoebae showing a higher percentage of positive samples (76%. In terms of public health, the presence of mycobacteria in water distribution systems may represent a potential risk especially for vulnerable people such as children, the elderly or immunocompromised individuals.

  20. Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology.

    Science.gov (United States)

    Gilichinsky, D A; Wilson, G S; Friedmann, E I; McKay, C P; Sletten, R S; Rivkina, E M; Vishnivetskaya, T A; Erokhina, L G; Ivanushkina, N E; Kochkina, G A; Shcherbakova, V A; Soina, V S; Spirina, E V; Vorobyova, E A; Fyodorov-Davydov, D G; Hallet, B; Ozerskaya, S M; Sorokovikov, V A; Laurinavichyus, K S; Shatilovich, A V; Chanton, J P; Ostroumov, V E; Tiedje, J M

    2007-04-01

    Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 10(4) viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems.

  1. Turnover of microbial lipids in the deep biosphere and growth of benthic archaeal populations.

    Science.gov (United States)

    Xie, Sitan; Lipp, Julius S; Wegener, Gunter; Ferdelman, Timothy G; Hinrichs, Kai-Uwe

    2013-04-09

    Deep subseafloor sediments host a microbial biosphere with unknown impact on global biogeochemical cycles. This study tests previous evidence based on microbial intact polar lipids (IPLs) as proxies of live biomass, suggesting that Archaea dominate the marine sedimentary biosphere. We devised a sensitive radiotracer assay to measure the decay rate of ([(14)C]glucosyl)-diphytanylglyceroldiether (GlcDGD) as an analog of archaeal IPLs in continental margin sediments. The degradation kinetics were incorporated in model simulations that constrained the fossil fraction of subseafloor IPLs and rates of archaeal turnover. Simulating the top 1 km in a generic continental margin sediment column, we estimated degradation rate constants of GlcDGD being one to two orders of magnitude lower than those of bacterial IPLs, with half-lives of GlcDGD increasing with depth to 310 ky. Given estimated microbial community turnover times of 1.6-73 ky in sediments deeper than 1 m, 50-96% of archaeal IPLs represent fossil signals. Consequently, previous lipid-based estimates of global subseafloor biomass probably are too high, and the widely observed dominance of archaeal IPLs does not rule out a deep biosphere dominated by Bacteria. Reverse modeling of existing concentration profiles suggest that archaeal IPL synthesis rates decline from around 1,000 pg⋅mL(-1) sediment⋅y(-1) at the surface to 0.2 pg⋅mL(-1)⋅y(-1) at 1 km depth, equivalent to production of 7 × 10(5) to 140 archaeal cells⋅mL(-1) sediment⋅y(-1), respectively. These constraints on microbial growth are an important step toward understanding the relationship between the deep biosphere and the carbon cycle.

  2. Microbial population analysis of the midgut of Melophagus ovinus via high-throughput sequencing

    OpenAIRE

    Duan, De-Yong; Liu, Guo-Hua; Cheng, Tian-Yin; Wang, Ya-Qin

    2017-01-01

    Background Melophagus ovinus, one of the most common haematophagous ectoparasites of sheep, can cause anaemia and reductions in weight gain, wool growth and hide value. However, no information is available about the microfloral structure of the midgut of this ectoparasite. In the present study, we investigated the microbial community structure of the midgut contents of fully engorged female and male M. ovinus using Illumina HiSeq. Results The phylum showing the highest abundance was Proteobac...

  3. Among-Population Variation in Microbial Community Structure in the Floral Nectar of the Bee-Pollinated Forest Herb Pulmonaria officinalis L

    Science.gov (United States)

    Jacquemyn, Hans; Lenaerts, Marijke; Brys, Rein; Willems, Kris; Honnay, Olivier; Lievens, Bart

    2013-01-01

    Background Microbial communities in floral nectar have been shown to be characterized by low levels of species diversity, yet little is known about among-plant population variation in microbial community composition. Methodology/Principal Findings We investigated the microbial community structure (yeasts and bacteria) in floral nectar of ten fragmented populations of the bee-pollinated forest herb Pulmonaria officinalis. We also explored possible relationships between plant population size and microbial diversity in nectar, and related microbial community composition to the distance separating plant populations. Culturable bacteria and yeasts occurring in the floral nectar of a total of 100 plant individuals were isolated and identified by partially sequencing the 16S rRNA gene and D1/D2 domains of the 26S rRNA gene, respectively. A total of 9 and 11 yeast and 28 and 39 bacterial OTUs was found, taking into account a 3% (OTU0.03) and 1% sequence dissimilarity cut-off (OTU0.01). OTU richness at the plant population level (i.e. the number of OTUs per population) was low for yeasts (mean: 1.7, range: 0–4 OTUs0.01/0.03 per population), whereas on average 6.9 (range: 2–13) OTUs0.03 and 7.9 (range 2–16) OTUs0.01 per population were found for bacteria. Both for yeasts and bacteria, OTU richness was not significantly related to plant population size. Similarity in community composition among populations was low (average Jaccard index: 0.14), and did not decline with increasing distance between populations. Conclusions/Significance We found low similarity in microbial community structure among populations, suggesting that the assembly of nectar microbiota is to a large extent context-dependent. Although the precise factors that affect variation in microbial community structure in floral nectar require further study, our results indicate that both local and regional processes may contribute to among-population variation in microbial community structure in nectar. PMID

  4. Using microbial desalination cells to reduce water salinity prior to reverse osmosis

    KAUST Repository

    Mehanna, Maha; Saito, Tomonori; Yan, Jingling; Hickner, Michael; Cao, Xiaoxin; Huang, Xia; Logan, Bruce E.

    2010-01-01

    type of air-cathode MDC containing three equally sized chambers. A single cycle of operation using a 1 g L -1 acetate solution reduced the conductivity of salt water (5 g L-1 NaCl) by 43 ± 6%, and produced a maximum power density of 480 mW m-2 with a

  5. Performance evaluation and microbial community analysis of the function and fate of ammonia in a sulfate-reducing EGSB reactor.

    Science.gov (United States)

    Wang, Depeng; Liu, Bo; Ding, Xinchun; Sun, Xinbo; Liang, Zi; Sheng, Shixiong; Du, Lingfeng

    2017-10-01

    Ammonia is widely distributed in sulfate-reducing bioreactor dealing with sulfate wastewater, which shows potential effect on the metabolic pathway of sulfate and ammonia. This study investigates the sulfate-reducing efficiency and microbial community composition in the sulfate-reducing EGSB reactor with the increasing ammonia loading. Results indicated that, compared with low ammonia loading (166-666 mg/L), the sulfate and organic matter removal efficiencies were improved gradually with the appropriate ammonia loading (1000-2000 mg/L), which increased from 63.58 ± 3.81 to 71.08 ± 1.36% and from 66.24 ± 1.32 to 81.88 ± 1.83%, respectively. Meanwhile, with the appropriate ratio of ammonia and sulfate (1.5-3.0) and hydraulic retention time (21 h), the sulfate-reducing anaerobic ammonia oxidation (SRAO) process was occurred efficiently, inducing the accumulation of S 0 (270 mg/L) and the simultaneous ammonia removal (70.83%) in EGSB reactor. Moreover, the key sulfate-reducing bacteria (SRB) (Desulfovibrio) and denitrification bacteria (Pseudomonas and Alcaligenes) were responsible for the sulfate and nitrogen removal in these phases, which accounted for 3.66-5.54 and 3.85-9.13%, respectively. However, as the ammonia loading higher than 3000 mg/L (phases 9 and 10), the sulfate-reducing efficiency was decreased to only 28.3 ± 1.26% with the ammonia removal rate of 18.4 ± 3.37% in the EGSB reactor. Meanwhile, the predominant SRB in phases 9 and 10 were Desulfomicrobium (1.22-1.99%) and Desulfocurvus (4.0-5.46%), and the denitrification bacteria accounted for only 0.88% (phase 10), indicating the low nitrogen removal rate.

  6. Microbial ecology of two hot springs of Sikkim: Predominate population and geochemistry.

    Science.gov (United States)

    Najar, Ishfaq Nabi; Sherpa, Mingma Thundu; Das, Sayak; Das, Saurav; Thakur, Nagendra

    2018-10-01

    Northeastern regions of India are known for their floral and faunal biodiversity. Especially the state of Sikkim lies in the eastern Himalayan ecological hotspot region. The state harbors many sulfur rich hot springs which have therapeutic and spiritual values. However, these hot springs are yet to be explored for their microbial ecology. The development of neo generation techniques such as metagenomics has provided an opportunity for inclusive study of microbial community of different environment. The present study describes the microbial diversity in two hot springs of Sikkim that is Polok and Borong with the assist of culture dependent and culture independent approaches. The culture independent techniques used in this study were next generation sequencing (NGS) and Phospholipid Fatty Acid Analysis (PLFA). Having relatively distinct geochemistry both the hot springs are thermophilic environments with the temperature range of 50-77 °C and pH range of 5-8. Metagenomic data revealed the dominance of bacteria over archaea. The most abundant phyla were Proteobacteria and Bacteroidetes although other phyla were also present such as Acidobacteria, Nitrospirae, Firmicutes, Proteobacteria, Parcubacteria and Spirochaetes. The PLFA studies have shown the abundance of Gram Positive bacteria followed by Gram negative bacteria. The culture dependent technique was correlative with PLFA studies. Most abundant bacteria as isolated and identified were Gram-positive genus Geobacillus and Anoxybacillus. The genus Geobacillus has been reported for the first time in North-Eastern states of India. The Geobacillus species obtained from the concerned hot springs were Geobacillus toebii, Geobacillus lituanicus, Geobacillus Kaustophillus and the Anoxybacillus species includes Anoxybacillus gonensis and Anoxybacillus Caldiproteolyticus. The distribution of major genera and their statistical correlation analyses with the geochemistry of the springs predicted that the temperature, p

  7. Enhancement of the sweep efficiency of waterflooding operations by the in-situ microbial population of petroleum reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.R.; Vadie, A.A.; Stephens, J.O.; Azadpour, A.

    1995-12-31

    Live cores were obtained from five reservoirs using special precautions to prevent contamination by exogenous microorganisms and minimize exposure to oxygen. The depths from which the cores were obtained ranged from 2,705 ft to 6,568 ft. Core plugs were cut radially from live cores, encased in heat-shrink plastic tubes, placed in core holders, and fitted with inlets and outlets. Nutrient additions stimulated the in-situ microbial population to increase, dissolve stratal material, produce gases, and release oil. Reduction in flow through the core plugs was observed in some cases, while in other cases flow was increased, probably due to the dissolution of carbonates in the formation. A field demonstration of the ability of the in-situ microbial population to increase oil recovery by blocking the more permeable zones of the reservoir is currently underway. This demonstration is being conducted in the North Blowhorn Creek Unit situated in Lamar County, Alabama. Live cores were obtained from a newly drilled well in the field and tested as described above. The field project involves four test patterns each including one injector, four to five producers, and a comparable control injector with its four to five producers. Nutrient injection in the field began November 1994.

  8. The Influence of Age and Gender on Skin-Associated Microbial Communities in Urban and Rural Human Populations.

    Directory of Open Access Journals (Sweden)

    Shi Ying

    Full Text Available Differences in the bacterial community structure associated with 7 skin sites in 71 healthy people over five days showed significant correlations with age, gender, physical skin parameters, and whether participants lived in urban or rural locations in the same city. While body site explained the majority of the variance in bacterial community structure, the composition of the skin-associated bacterial communities were predominantly influenced by whether the participants were living in an urban or rural environment, with a significantly greater relative abundance of Trabulsiella in urban populations. Adults maintained greater overall microbial diversity than adolescents or the elderly, while the intragroup variation among the elderly and rural populations was significantly greater. Skin-associated bacterial community structure and composition could predict whether a sample came from an urban or a rural resident ~5x greater than random.

  9. Allee effect: the story behind the stabilization or extinction of microbial ecosystem.

    Science.gov (United States)

    Goswami, Madhurankhi; Bhattacharyya, Purnita; Tribedi, Prosun

    2017-03-01

    A population exhibiting Allee effect shows a positive correlation between population fitness and population size or density. Allee effect decides the extinction or conservation of a microbial population and thus appears to be an important criterion in population ecology. The underlying factor of Allee effect that decides the stabilization and extinction of a particular population density is the threshold or the critical density of their abundance. According to Allee, microbial populations exhibit a definite, critical or threshold density, beyond which the population fitness of a particular population increases with the rise in population density and below it, the population fitness goes down with the decrease in population density. In particular, microbial population displays advantageous traits such as biofilm formation, expression of virulence genes, spore formation and many more only at a high population density. It has also been observed that microorganisms exhibiting a lower population density undergo complete extinction from the residual microbial ecosystem. In reference to Allee effect, decrease in population density or size introduces deleterious mutations among the population density through genetic drift. Mutations are carried forward to successive generations resulting in its accumulation among the population density thus reducing its microbial fitness and thereby increasing the risk of extinction of a particular microbial population. However, when the microbial load is high, the chance of genetic drift is less, and through the process of biofilm formation, the cooperation existing among the microbial population increases that increases the microbial fitness. Thus, the high microbial population through the formation of microbial biofilm stabilizes the ecosystem by increasing fitness. Taken together, microbial fitness shows positive correlation with the ecosystem conservation and negative correlation with ecosystem extinction.

  10. Trichoderma-Based Biostimulants Modulate Rhizosphere Microbial Populations and Improve N Uptake Efficiency, Yield, and Nutritional Quality of Leafy Vegetables

    Directory of Open Access Journals (Sweden)

    Nunzio Fiorentino

    2018-06-01

    Full Text Available Microbial inoculants such as Trichoderma-based products are receiving great interest among researchers and agricultural producers for their potential to improve crop productivity, nutritional quality as well as resistance to plant pathogens/pests and numerous environmental stresses. Two greenhouse experiments were conducted to assess the effects of Trichoderma-based biostimulants under suboptimal, optimal and supraoptimal levels of nitrogen (N fertilization in two leafy vegetables: Iceberg lettuce (Lactuca sativa L. and rocket (Eruca sativa Mill.. The yield, nutritional characteristics, N uptake and mineral composition were analyzed for each vegetable crop after inoculation with Trichoderma strains T. virens (GV41 or T. harzianum (T22, and results were compared to non-inoculated plants. In addition, the effect of the Trichoderma-based biostimulants on microbes associated with the rhizosphere in terms of prokaryotic and eukaryotic composition and concentration using DGGE was also evaluated. Trichoderma-based biostimulants, in particular GV41, positively increased lettuce and rocket yield in the unfertilized plots. The highest marketable lettuce fresh yield was recorded with either of the biostimulant inoculations when plants were supplied with optimal levels of N. The inoculation of rocket with GV41, and to a lesser degree with T22, elicited an increase in total ascorbic acid under both optimal and high N conditions. T. virens GV41 increased N-use efficiency of lettuce, and favored the uptake of native N present in the soil of both lettuce and rocket. The positive effect of biostimulants on nutrient uptake and crop growth was species-dependent, being more marked with lettuce. The best biostimulation effects from the Trichoderma treatments were observed in both crops when grown under low N availability. The Trichoderma inoculation strongly influenced the composition of eukaryotic populations in the rhizosphere, in particularly exerting different

  11. Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

    2001-01-01

    Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs

  12. Effect of Saccharomyces cerevisiae on alfalfa nutrient degradation characteristics and rumen microbial populations of steers fed diets with different concentrate-to-forage ratios.

    Science.gov (United States)

    Ding, Gengzhi; Chang, Ying; Zhao, Liping; Zhou, Zhenming; Ren, Liping; Meng, Qingxiang

    2014-01-01

    Live yeast (Saccharomyces cerevisiae) constitutes an effective additive for animal production; its probiotic effect may be related to the concentrate-to-forage ratio (CTFR). The objective of this study was to assess the effects of S. cerevisiae (SC) on fiber degradation and rumen microbial populations in steers fed diets with different levels of dietary concentrate. Ten Simmental × Local crossbred steers (450 ± 50 kg BW) were assigned to a control group or an SC group. Both groups were fed the same basal diet but the SC group received SC supplementation (8 × 10(9) cfu/h/d through the ruminal fistula) following a two-period crossover design. Each period consisted of four phases, each of which lasted 17 d: 10 d for dietary adaptation, 6 d for degradation study, and 1 d for rumen sample collection. From the 1(st) to the 4(th) phase, steers were fed in a stepwise fashion with increasing CTFRs, i.e., 30:70, 50:50, 70:30, and 90:10. The kinetics of dry matter and fiber degradation of alfalfa pellets were evaluated; the rumen microbial populations were detected using real-time PCR. The results revealed no significant (P > 0.05) interactions between dietary CTFR and SC for most parameters. Dietary CTFR had a significant effect (P trend for these parameters. SC supplementation significantly (P trend of rumen fungi and protozoa in SC group (P < 0.1); copies of total bacteria in SC group were significantly higher (P < 0.05). Additionally, percentage of Ruminobacter amylophilus was significantly lower (P < 0.05) but percentage of Selenomonas ruminantium was significantly higher (P < 0.05) in the SC group. In a word, dietary CTFR had a significant effect on degradation characteristics of forage and rumen microbial population. S. cerevisiae had positive effects on DM and NDF degradation rate or effective degradability of forage; S. cerevisiae increased rumen total bacteria, fungi, protozoa, and lactate-utilizing bacteria but reduced

  13. Taking Exception. Reduced mortality leads to population growth: an inconvenient truth.

    Science.gov (United States)

    Shelton, James D

    2014-05-01

    Reduced mortality has been the predominant cause of the marked global population growth over the last 3/4 of a century. While improved child survival increases motivation to reduce fertility, it comes too little and too late to forestall substantial population growth. And, beyond motivation, couples need effective means to control their fertility. It is an inconvenient truth that reducing child mortality contributes considerably to the population growth destined to compromise the quality of life of many, particularly in sub-Saharan Africa. Vigorous child survival programming is of course imperative. Wide access to voluntary family planning can help mitigate that growth and provide many other benefits.

  14. Long Term Performance of an Arsenite-Oxidizing-Chlorate-Reducing Microbial Consortium in an Upflow Anaerobic Sludge Bed (UASB) Bioreactor

    Science.gov (United States)

    Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A.

    2011-01-01

    A chlorate (ClO3−) reducing microbial consortium oxidized arsenite (As(III)) to arsenate (As(V)) in an upflow anaerobic sludge-bed bioreactor over 550 d operation. As(III) was converted with high conversion efficiencies (>98%) at volumetric loadings ranging from 0.45 to 1.92 mmol As/(Lreactor d). The oxidation of As(III) was linked to the complete reduction of ClO3− to Cl− and H2O, as demonstrated by a molar ratio of approximately 3.0 mol As(III) oxidized per mole of Cl− formed and by the greatly lowered ClO3−-reducing capacity without As(III) feeding. An autotrophic enrichment culture was established from the bioreactor biofilm. A 16S rRNA gene clone library indicated that the culture was dominated by Dechloromonas, and Stenotrophomonas as well as genera within the family Comamonadaceae. The results indicate that the oxidation of As(III) to less mobile As(V) utilizing ClO3− as a terminal electron acceptor provides a sustainable bioremediation strategy for arsenic contamination in anaerobic environments. PMID:21333531

  15. Evaluation of treatments with hot water, chemicals and ventilated containers to reduce microbial spoilage in irradiated potatoes

    International Nuclear Information System (INIS)

    Shirsat, S.G.; Thomas, P.; Nair, P.M.

    1991-01-01

    Potatoes irradiated to control sprouting were dipped in: hot water (56°C, 5 min; 52°C, 10, 15 and 20 min); cold (25°C, 5 min) or hot (56°C, 5 min) salicylic acid (1000 and 2000 ppm); or sodium hypochlorite (0.1 and 0.2%, 5 min); or dusted with salicylic acid (1 and 2%), to try to reduce the incidence of bacterial soft rot (Erwinia sp.) during controlled temperature (10°C, 15°C) and ambient temperature (20–34°C) storage. All treatments, particularly hot water and hot salicylic acid dip, increased microbial spoilage, possibly as a result of handling damage during the treatments combined with the inhibition of wound periderm formation as a result of irradiation. Storing irradiated tubers in well ventilated containers reduced soft rot compared to storing them in sacks and after 6 months storage at 10, 15 and 20–34°C, 95, 90 and 77% respectively were healthy and marketable. (author)

  16. Distribution of phototrophic populations and primary production in a microbial mat from the Ebro Delta, Spain.

    Science.gov (United States)

    Martínez-Alonso, Maira; Mir, Joan; Caumette, Pierre; Gaju, Núria; Guerrero, Ricardo; Esteve, Isabel

    2004-03-01

    Microbial mats arising in the sand flats of the Ebro Delta (Tarragona, Spain) were investigated during the summer season, when the community was highly developed. These mats are composed of three pigmented layers of phototrophic organisms, an upper brown layer mainly composed of Lyngbya aestuarii and diatoms, an intermediate green layer of the cyanobacterium Microcoleus chthonoplastes, and an underlying pink layer of a so-far unidentified purple sulfur bacterium. In the photic zone, oxygenic phototrophs constitute about 58% of total photosynthetic biomass, measured as biovolume, and anoxygenic phototrophs represent 42%. Diatoms constitute 11.8% of the oxygenic biomass, M. chthonoplastes 61.2%, and L. aestuarii and coccoid cyanobacteria 20.6 and 6.4%, respectively. In this laminated community, organic matter has an autochthonous origin, and photosynthesis is the most important source of organic carbon. Oxygen production reaches up to 27.2 mmol O(2) m(-2) h(-1), measured at 1000 microE m(-2) s(-1) light intensity, whereas oxidation of sulfide in the light has been calculated to be 18.6 mmol S m(-2) h(-1). This amount represents 26% of the total photosynthetic production in terms of photoassimilated carbon, demonstrating the important role of anoxygenic phototrophs as primary producers in the pink layer of Ebro Delta microbial mats.

  17. Distribution and composition of microbial populations in a landfill leachate contaminated aquifer (Grindsted, Denmark)

    DEFF Research Database (Denmark)

    Ludvigsen, L.; Albrechtsen, H.-J.; Ringelberg, D.

    1999-01-01

    To investigate whether landfill leachates affected the microbial biomass and/or community composition of the extant microbiota, 37 samples were collected along a 305-m transect of a shallow landfill-leachate polluted aquifer. The samples were analyzed for total numbers of bacteria by use of the a......To investigate whether landfill leachates affected the microbial biomass and/or community composition of the extant microbiota, 37 samples were collected along a 305-m transect of a shallow landfill-leachate polluted aquifer. The samples were analyzed for total numbers of bacteria by use...... of the acridine orange direct count method (AODC). Numbers of dominant, specific groups of bacteria and total numbers of protozoa were measured by use of the most probable number method (MPN). Viable biomass estimates were obtained from measures of ATP and ester-linked phospholipid fatty acid (PLFA......) concentrations. The estimated numbers of total bacteria by direct counts were relatively constant throughout the aquifer, ranging from a low of 4.8 × 106 cells/g dry weight (dw) to a high of 5.3 × 107 cells/g dw. Viable biomass estimates based on PLFA concentrations were one to three orders of magnitude lower...

  18. Metagenomics reveals pervasive bacterial populations and reduced community diversity across the Alaska tundra ecosystem

    Directory of Open Access Journals (Sweden)

    Eric Robert Johnston

    2016-04-01

    Full Text Available How soil microbial communities contrast with respect to taxonomic and functional composition within and between ecosystems remains an unresolved question that is central to predicting how global anthropogenic change will affect soil functioning and services. In particular, it remains unclear how small-scale observations of soil communities based on the typical volume sampled (1-2 grams are generalizable to ecosystem-scale responses and processes. This is especially relevant for remote, northern latitude soils, which are challenging to sample and are also thought to be more vulnerable to climate change compared to temperate soils. Here, we employed well-replicated shotgun metagenome and 16S rRNA gene amplicon sequencing to characterize community composition and metabolic potential in Alaskan tundra soils, combining our own datasets with those publically available from distant tundra and temperate grassland and agriculture habitats. We found that the abundance of many taxa and metabolic functions differed substantially between tundra soil metagenomes relative to those from temperate soils, and that a high degree of OTU-sharing exists between tundra locations. Tundra soils were an order of magnitude less complex than their temperate counterparts, allowing for near-complete coverage of microbial community richness (~92% breadth by sequencing, and the recovery of twenty-seven high-quality, almost complete (>80% completeness population bins. These population bins, collectively, made up to ~10% of the metagenomic datasets, and represented diverse taxonomic groups and metabolic lifestyles tuned toward sulfur cycling, hydrogen metabolism, methanotrophy, and organic matter oxidation. Several population bins, including members of Acidobacteria, Actinobacteria, and Proteobacteria, were also present in geographically distant (~100-530 km apart tundra habitats (full genome representation and up to 99.6% genome-derived average nucleotide identity. Collectively

  19. Population-Sequencing as a Biomarker of Burkholderia mallei and Burkholderia pseudomallei Evolution through Microbial Forensic Analysis

    Directory of Open Access Journals (Sweden)

    John P. Jakupciak

    2013-01-01

    Full Text Available Large-scale genomics projects are identifying biomarkers to detect human disease. B. pseudomallei and B. mallei are two closely related select agents that cause melioidosis and glanders. Accurate characterization of metagenomic samples is dependent on accurate measurements of genetic variation between isolates with resolution down to strain level. Often single biomarker sensitivity is augmented by use of multiple or panels of biomarkers. In parallel with single biomarker validation, advances in DNA sequencing enable analysis of entire genomes in a single run: population-sequencing. Potentially, direct sequencing could be used to analyze an entire genome to serve as the biomarker for genome identification. However, genome variation and population diversity complicate use of direct sequencing, as well as differences caused by sample preparation protocols including sequencing artifacts and mistakes. As part of a Department of Homeland Security program in bacterial forensics, we examined how to implement whole genome sequencing (WGS analysis as a judicially defensible forensic method for attributing microbial sample relatedness; and also to determine the strengths and limitations of whole genome sequence analysis in a forensics context. Herein, we demonstrate use of sequencing to provide genetic characterization of populations: direct sequencing of populations.

  20. Brain microbial populations in HIV/AIDS: α-proteobacteria predominate independent of host immune status.

    Directory of Open Access Journals (Sweden)

    William G Branton

    Full Text Available The brain is assumed to be a sterile organ in the absence of disease although the impact of immune disruption is uncertain in terms of brain microbial diversity or quantity. To investigate microbial diversity and quantity in the brain, the profile of infectious agents was examined in pathologically normal and abnormal brains from persons with HIV/AIDS [HIV] (n = 12, other disease controls [ODC] (n = 14 and in cerebral surgical resections for epilepsy [SURG] (n = 6. Deep sequencing of cerebral white matter-derived RNA from the HIV (n = 4 and ODC (n = 4 patients and SURG (n = 2 groups revealed bacterially-encoded 16 s RNA sequences in all brain specimens with α-proteobacteria representing over 70% of bacterial sequences while the other 30% of bacterial classes varied widely. Bacterial rRNA was detected in white matter glial cells by in situ hybridization and peptidoglycan immunoreactivity was also localized principally in glia in human brains. Analyses of amplified bacterial 16 s rRNA sequences disclosed that Proteobacteria was the principal bacterial phylum in all human brain samples with similar bacterial rRNA quantities in HIV and ODC groups despite increased host neuroimmune responses in the HIV group. Exogenous viruses including bacteriophage and human herpes viruses-4, -5 and -6 were detected variably in autopsied brains from both clinical groups. Brains from SIV- and SHIV-infected macaques displayed a profile of bacterial phyla also dominated by Proteobacteria but bacterial sequences were not detected in experimentally FIV-infected cat or RAG1⁻/⁻ mouse brains. Intracerebral implantation of human brain homogenates into RAG1⁻/⁻ mice revealed a preponderance of α-proteobacteria 16 s RNA sequences in the brains of recipient mice at 7 weeks post-implantation, which was abrogated by prior heat-treatment of the brain homogenate. Thus, α-proteobacteria represented the major bacterial component of the primate brain

  1. Detailed analysis of the microbial population in Malaysian spontaneous cocoa pulp fermentations reveals a core and variable microbiota.

    Directory of Open Access Journals (Sweden)

    Esther Meersman

    Full Text Available The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a "core" and a "variable" part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations ("core" yeasts, and a large number of yeasts that only occur in lower numbers and specific fermentations ("variable" yeasts. Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.

  2. Influence of cereal non-starch polysaccharides on ileo-caecal and rectal microbial populations in growing pigs

    DEFF Research Database (Denmark)

    Høgberg, Ann; Lindberg, Jan; Leser, Thomas

    2004-01-01

    The effect of cereal non-starch polysaccharides (NSP) on the gut microbial populations was studied in 5 growing pigs between 39-116 kg body weight according to a Latin square design. The diets were composed to contain different NSP levels. The control diet had a normal NSP content (139 g/kg dry...... matter (DM)), 2 diets had a low total amount of NSP (95 and 107 g/kg DM) and 2 diets had a high amount of total NSP (191 and 199 g/kg DM). Furthermore, one of the diets within each category had a content of insoluble NSP similar to the control diet and one had a high content of insoluble NSP. Samples...... were collected from the ileum, via intestinal post valve T-caecum (PVTC) cannulas surgically inserted at the ileo-caecal ostium, and from the rectum. The total microbial flora of the ileal samples were analysed for by defining base pair length with terminal restriction fraction length polymorphism (T...

  3. Mapping the Centimeter-Scale Spatial Variability of PAHs and Microbial Populations in the Rhizosphere of Two Plants.

    Directory of Open Access Journals (Sweden)

    Amélia Bourceret

    Full Text Available Rhizoremediation uses root development and exudation to favor microbial activity. Thus it can enhance polycyclic aromatic hydrocarbon (PAH biodegradation in contaminated soils. Spatial heterogeneity of rhizosphere processes, mainly linked to the root development stage and to the plant species, could explain the contrasted rhizoremediation efficiency levels reported in the literature. Aim of the present study was to test if spatial variability in the whole plant rhizosphere, explored at the centimetre-scale, would influence the abundance of microorganisms (bacteria and fungi, and the abundance and activity of PAH-degrading bacteria, leading to spatial variability in PAH concentrations. Two contrasted rhizospheres were compared after 37 days of alfalfa or ryegrass growth in independent rhizotron devices. Almost all spiked PAHs were degraded, and the density of the PAH-degrading bacterial populations increased in both rhizospheres during the incubation period. Mapping of multiparametric data through geostatistical estimation (kriging revealed that although root biomass was spatially structured, PAH distribution was not. However a greater variability of the PAH content was observed in the rhizosphere of alfalfa. Yet, in the ryegrass-planted rhizotron, the Gram-positive PAH-degraders followed a reverse depth gradient to root biomass, but were positively correlated to the soil pH and carbohydrate concentrations. The two rhizospheres structured the microbial community differently: a fungus-to-bacterium depth gradient similar to the root biomass gradient only formed in the alfalfa rhizotron.

  4. Detailed analysis of the microbial population in Malaysian spontaneous cocoa pulp fermentations reveals a core and variable microbiota.

    Science.gov (United States)

    Meersman, Esther; Steensels, Jan; Mathawan, Melissa; Wittocx, Pieter-Jan; Saels, Veerle; Struyf, Nore; Bernaert, Herwig; Vrancken, Gino; Verstrepen, Kevin J

    2013-01-01

    The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a "core" and a "variable" part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations ("core" yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations ("variable" yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.

  5. Increased extinction potential of insular fish populations with reduced life history variation and low genetic diversity.

    Science.gov (United States)

    Hellmair, Michael; Kinziger, Andrew P

    2014-01-01

    Theoretical work has shown that reduced phenotypic heterogeneity leads to population instability and can increase extinction potential, yet few examples exist of natural populations that illustrate how varying levels expressed diversity may influence population persistence, particularly during periods of stochastic environmental fluctuation. In this study, we assess levels of expressed variation and genetic diversity among demographically independent populations of tidewater goby (Eucyclogobius newberryi), show that reductions in both factors typically coincide, and describe how low levels of diversity contribute to the extinction risk of these isolated populations. We illustrate that, for this annual species, continuous reproduction is a safeguard against reproductive failure by any one population segment, as natural, stochastically driven salinity increases frequently result in high mortality among juvenile individuals. Several study populations deviated from the natural pattern of year-round reproduction typical for the species, rendering those with severely truncated reproductive periods vulnerable to extinction in the event of environmental fluctuation. In contrast, demographically diverse populations are more likely to persist through such periods through the continuous presence of adults with broader physiological tolerance to abrupt salinity changes. Notably, we found a significant correlation between genetic diversity and demographic variation in the study populations, which could be the result of population stressors that restrict both of these diversity measures simultaneously, or suggestive of a causative relationship between these population characteristics. These findings demonstrate the importance of biocomplexity at the population level, and assert that the maintenance of diversity contributes to population resilience and conservation of this endangered species.

  6. Increased extinction potential of insular fish populations with reduced life history variation and low genetic diversity.

    Directory of Open Access Journals (Sweden)

    Michael Hellmair

    Full Text Available Theoretical work has shown that reduced phenotypic heterogeneity leads to population instability and can increase extinction potential, yet few examples exist of natural populations that illustrate how varying levels expressed diversity may influence population persistence, particularly during periods of stochastic environmental fluctuation. In this study, we assess levels of expressed variation and genetic diversity among demographically independent populations of tidewater goby (Eucyclogobius newberryi, show that reductions in both factors typically coincide, and describe how low levels of diversity contribute to the extinction risk of these isolated populations. We illustrate that, for this annual species, continuous reproduction is a safeguard against reproductive failure by any one population segment, as natural, stochastically driven salinity increases frequently result in high mortality among juvenile individuals. Several study populations deviated from the natural pattern of year-round reproduction typical for the species, rendering those with severely truncated reproductive periods vulnerable to extinction in the event of environmental fluctuation. In contrast, demographically diverse populations are more likely to persist through such periods through the continuous presence of adults with broader physiological tolerance to abrupt salinity changes. Notably, we found a significant correlation between genetic diversity and demographic variation in the study populations, which could be the result of population stressors that restrict both of these diversity measures simultaneously, or suggestive of a causative relationship between these population characteristics. These findings demonstrate the importance of biocomplexity at the population level, and assert that the maintenance of diversity contributes to population resilience and conservation of this endangered species.

  7. Microbial population analysis of the midgut of Melophagus ovinus via high-throughput sequencing.

    Science.gov (United States)

    Duan, De-Yong; Liu, Guo-Hua; Cheng, Tian-Yin; Wang, Ya-Qin

    2017-08-09

    Melophagus ovinus, one of the most common haematophagous ectoparasites of sheep, can cause anaemia and reductions in weight gain, wool growth and hide value. However, no information is available about the microfloral structure of the midgut of this ectoparasite. In the present study, we investigated the microbial community structure of the midgut contents of fully engorged female and male M. ovinus using Illumina HiSeq. The phylum showing the highest abundance was Proteobacteria (99.9%). The dominant bacterial genera in females and males were Bartonella, Arsenophonus and Wolbachia. Some less abundant bacterial genera were also detected, including Enterobacter, Acinetobacter, Halomonas, Shewanella, Bacillus and Staphylococcus. Bartonella, Arsenophonus and Wolbachia were the dominant bacterial genera in the midgut of female and male M. ovinus. Although detected, Enterobacter, Acinetobacter, Halomonas, Shewanella, Bacillus and Staphylococcus showed low abundances. Importantly, this is the first report of the presence of Arsenophonus, Wolbachia, Enterobacter, Halomonas, Shewanella, Bacillus and Staphylococcus in the midgut of M. ovinus.

  8. Production of biosurfactant from Bacillus licheniformis for microbial enhanced oil recovery and inhibition the growth of sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    H.S. El-Sheshtawy

    2015-06-01

    Full Text Available In this study, the bacterium Bacillus licheniformis has been isolated from oil reservoir; the ability of this bacterium to produce a biosurfactant was detected. Surface properties of the produced biosurfactant were confirmed by determining the emulsification power as well as surface and interfacial tension. The crude biosurfactant has been extracted from supernatant culture growth, and the yield of crude biosurfactant was about 1 g/l. Also, chemical structure of the produced biosurfactant was confirmed using FTIR analysis. Results revealed that, the emulsification power has been increased up to 96% and the surface tension decreased from 72 of distilled water to 36 mN/m after 72 h of incubation. The potential application of this bacterial species in microbial-enhanced oil recovery (MEOR was investigated. The percent of oil recovery was 16.6% upon application in a sand pack column designed to stimulate an oil recovery. It also showed antimicrobial activity against the growth of different strains of SRB (sulfate reducing bacteria. Results revealed that a complete inhibition of SRB growth using 1.0% crude biosurfactant is achieved after 3 h.

  9. Inoculation of soil with an Isoproturon degrading microbial community reduced the pool of "real non-extractable" Isoproturon residues.

    Science.gov (United States)

    Zhu, Xiaomin; Schroll, Reiner; Dörfler, Ulrike; Chen, Baoliang

    2018-03-01

    During pesticides degradation, biogenic non-extractable residues ("apparent NER") may not share the same environmental fate and risks with the "real NER" that are bound to soil matrix. It is not clear how microbial community (MC) inoculation for pesticides degradation would influence the NER composition. To investigate degradation efficiency of pesticides Isoproturon (IPU) and NER composition following MC inoculation, clay particles harboring MC that contains the IPU degrading strain, Sphingomonas sp., were inoculated into soil receiving 14 C-labeled IPU addition. Mineralization of IPU was greatly enhanced with MC inoculation that averagely 55.9% of the applied 14 C-IPU was consumed up into 14 CO 2 during 46 days soil incubation. Isoproturon degradation was more thorough with MC than that in the control: much less amount of metabolic products (4.6% of applied IPU) and NER (35.4%) formed in MC treatment, while the percentages were respectively 30.3% for metabolites and 49.8% for NER in the control. Composition of NER shifted with MC inoculation, that relatively larger amount of IPU was incorporated into the biogenic "apparent NER" in comparison with "real NER". Besides its well-recognized role on enhancing mineralization, MC inoculation with clay particles benefits soil pesticides remediation in term of reducing "real NER" formation, which has been previously underestimated. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers

    Energy Technology Data Exchange (ETDEWEB)

    Miletto, M.; Williams, K.H.; N' Guessan, A.L.; Lovley, D.R.

    2011-04-01

    Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory (bi)sulfite reductase gene transcript abundance in phylogenetically distinct sulfate-reducing populations was quantified during a field experiment in which acetate was added to uranium-contaminated groundwater. Analysis of dsrAB sequences prior to the addition of acetate indicated that Desulfobacteraceae, Desulfobulbaceae, and Syntrophaceae-related sulfate reducers were the most abundant. Quantifying dsrB transcripts of the individual populations suggested that Desulfobacteraceae initially had higher dsrB transcripts per cell than Desulfobulbaceae or Syntrophaceae populations, and that the activity of Desulfobacteraceae increased further when the metabolism of dissimilatory metal reducers competing for the added acetate declined. In contrast, dsrB transcript abundance in Desulfobulbaceae and Syntrophaceae remained relatively constant, suggesting a lack of stimulation by added acetate. The indication of higher sulfate-reducing activity in the Desulfobacteraceae was consistent with the finding that Desulfobacteraceae became the predominant component of the sulfate-reducing community. Discontinuing acetate additions resulted in a decline in dsrB transcript abundance in the Desulfobacteraceae. These results suggest that monitoring transcripts of dissimilatory (bi)sulfite reductase genes in distinct populations of sulfate reducers can provide insight into the relative rates of metabolism of different components of the sulfate-reducing community and their ability to respond to

  11. Influence of pulsed magnetic field on soybean (Glycine max L.) seed germination, seedling growth and soil microbial population.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Kumari, Bollipo Dyana Ranjitha

    2013-08-01

    The effects of pulsed magnetic field (PMF) treatment of soybean (Glycine max L. cv CO3) seeds were investigated on rate of seed germination, seedling growth, physico-chemical properties of seed leachates and soil microbial population under laboratory conditions. Seeds were exposed to PMF of 1500 nT at 0.1, 1.0 10.0 and 100.0 Hz for 5 h per day for 20 days, induced by enclosure coil systems. Non-treated seeds were considered as controls. All PMF treatments significantly increased the rate of seed germination, while 10 and 100 Hz PMFs showed the most effective response. The 1.0 and 10 Hz PMFs remarkably improved the fresh weight of shoots and roots, leaf area and plant height from seedlings from magnetically-exposed seeds compared to the control, while 10 Hz PMF increased the total soluble sugar, total protein and phenol contents. The leaf chlorophyll a, b and total chlorophyll were higher in PMF (10 and 100 Hz) pretreated plants, as compared to other treatments. In addition, activities of alpha-amylase, acid phosphatase, alkaline phosphatase, nitrate reductase, peroxidase and polyphenoloxidase were increased, while beta-amylase and protease activities were declined in PMF (10 Hz)-exposed soybean plants. Similarly, the capacity of absorbance of water by seeds and electrical conductivity of seed leachates were significantly enhanced by 10 Hz PMF exposure, whereas PMF (10 Hz) pretreated plants did not affect the microbial population in rhizosphere soil. The results suggested the potential of 10 Hz PMF treatment to enhance the germination and seedling growth of soybean.

  12. Evolution of increased phenotypic diversity enhances population performance by reducing sexual harassment in damselflies.

    Science.gov (United States)

    Takahashi, Yuma; Kagawa, Kotaro; Svensson, Erik I; Kawata, Masakado

    2014-07-18

    The effect of evolutionary changes in traits and phenotypic/genetic diversity on ecological dynamics has received much theoretical attention; however, the mechanisms and ecological consequences are usually unknown. Female-limited colour polymorphism in damselflies is a counter-adaptation to male mating harassment, and thus, is expected to alter population dynamics through relaxing sexual conflict. Here we show the side effect of the evolution of female morph diversity on population performance (for example, population productivity and sustainability) in damselflies. Our theoretical model incorporating key features of the sexual interaction predicts that the evolution of increased phenotypic diversity will reduce overall fitness costs to females from sexual conflict, which in turn will increase productivity, density and stability of a population. Field data and mesocosm experiments support these model predictions. Our study suggests that increased phenotypic diversity can enhance population performance that can potentially reduce extinction rates and thereby influence macroevolutionary processes.

  13. Petrophilic, Fe(III Reducing Exoelectrogen Citrobacter sp. KVM11, Isolated From Hydrocarbon Fed Microbial Electrochemical Remediation Systems

    Directory of Open Access Journals (Sweden)

    Krishnaveni Venkidusamy

    2018-03-01

    Full Text Available Exoelectrogenic biofilms capable of extracellular electron transfer are important in advanced technologies such as those used in microbial electrochemical remediation systems (MERS Few bacterial strains have been, nevertheless, obtained from MERS exoelectrogenic biofilms and characterized for bioremediation potential. Here we report the identification of one such bacterial strain, Citrobacter sp. KVM11, a petrophilic, iron reducing bacterial strain isolated from hydrocarbon fed MERS, producing anodic currents in microbial electrochemical systems. Fe(III reduction of 90.01 ± 0.43% was observed during 5 weeks of incubation with Fe(III supplemented liquid cultures. Biodegradation screening assays showed that the hydrocarbon degradation had been carried out by metabolically active cells accompanied by growth. The characteristic feature of diazo dye decolorization was used as a simple criterion for evaluating the electrochemical activity in the candidate microbe. The electrochemical activities of the strain KVM11 were characterized in a single chamber fuel cell and three electrode electrochemical cells. The inoculation of strain KVM11 amended with acetate and citrate as the sole carbon and energy sources has resulted in an increase in anodic currents (maximum current density of 212 ± 3 and 359 ± mA/m2 with respective coulombic efficiencies of 19.5 and 34.9% in a single chamber fuel cells. Cyclic voltammetry studies showed that anaerobically grown cells of strain KVM11 are electrochemically active whereas aerobically grown cells lacked the electrochemical activity. Electrobioremediation potential of the strain KVM11 was investigated in hydrocarbonoclastic and dye detoxification conditions using MERS. About 89.60% of 400 mg l-1 azo dye was removed during the first 24 h of operation and it reached below detection limits by the end of the batch operation (60 h. Current generation and biodegradation capabilities of strain KVM11 were examined using an

  14. Petrophilic, Fe(III) Reducing Exoelectrogen Citrobacter sp. KVM11, Isolated From Hydrocarbon Fed Microbial Electrochemical Remediation Systems

    Science.gov (United States)

    Venkidusamy, Krishnaveni; Hari, Ananda Rao; Megharaj, Mallavarapu

    2018-01-01

    Exoelectrogenic biofilms capable of extracellular electron transfer are important in advanced technologies such as those used in microbial electrochemical remediation systems (MERS) Few bacterial strains have been, nevertheless, obtained from MERS exoelectrogenic biofilms and characterized for bioremediation potential. Here we report the identification of one such bacterial strain, Citrobacter sp. KVM11, a petrophilic, iron reducing bacterial strain isolated from hydrocarbon fed MERS, producing anodic currents in microbial electrochemical systems. Fe(III) reduction of 90.01 ± 0.43% was observed during 5 weeks of incubation with Fe(III) supplemented liquid cultures. Biodegradation screening assays showed that the hydrocarbon degradation had been carried out by metabolically active cells accompanied by growth. The characteristic feature of diazo dye decolorization was used as a simple criterion for evaluating the electrochemical activity in the candidate microbe. The electrochemical activities of the strain KVM11 were characterized in a single chamber fuel cell and three electrode electrochemical cells. The inoculation of strain KVM11 amended with acetate and citrate as the sole carbon and energy sources has resulted in an increase in anodic currents (maximum current density) of 212 ± 3 and 359 ± mA/m2 with respective coulombic efficiencies of 19.5 and 34.9% in a single chamber fuel cells. Cyclic voltammetry studies showed that anaerobically grown cells of strain KVM11 are electrochemically active whereas aerobically grown cells lacked the electrochemical activity. Electrobioremediation potential of the strain KVM11 was investigated in hydrocarbonoclastic and dye detoxification conditions using MERS. About 89.60% of 400 mg l-1 azo dye was removed during the first 24 h of operation and it reached below detection limits by the end of the batch operation (60 h). Current generation and biodegradation capabilities of strain KVM11 were examined using an initial

  15. Stability of U(VI) and Tc(VII) Reducing Microbial Communities to Environmental Perturbation: Development and Testing of a Thermodynamic Network Model

    International Nuclear Information System (INIS)

    McKinley, James P.; Istok, Jonathan

    2005-01-01

    Previously published research from in situ field experiments at the NABIR Field Research Center have shown that cooperative metabolism of denitrifiers and Fe(III)/sulfate reducers is essential for creating subsurface conditions favorable for U(VI) and Tc(VII) bioreduction (Istok et al., 2004). The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on the composition and functional stability of subsurface microbial communities. The overall scientific hypothesis is that a thermodynamic analysis of the energy-yielding reactions performed by broadly defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change. An interactive computer program was developed to calculate the overall growth equation and free energy yield for microorganisms that grow by coupling selected combinations of electron acceptor and electron donor half-reactions. Each group performs a specific function (e.g. oxidation of acetate coupled to reduction of nitrate); collectively the groups provide a theoretical description of the entire natural microbial community. The microbial growth data are combined with an existing thermodynamic data base for associated geochemical reactions and used to simulate the coupled microbial-geochemical response of a complex natural system to substrate addition or any other environmental perturbations

  16. Evaluating the microbial community and gene regulation involved in crystallization kinetics of ZnS formation in reduced environments

    Science.gov (United States)

    Falk, Nicholas; Chaganti, Subba Rao; Weisener, Christopher G.

    2018-01-01

    In anoxic environments, sulfate-reducing bacteria (SRB) may precipitate sparingly-soluble, fine-grained sulfides as by-products of dissimilatory sulfate reduction. This bio-mechanism lends importance to acid rock drainage (ARD) remediation efforts for its ability to immobilize harmful metals from contaminant pathways, including Zn. However, SRB often coexist alongside multiple bacterial guilds in these environments, and may be sustained or hindered by the activities and metabolic by-products of their cohorts, driven by the commonly available substrates. Thus, the effectiveness of onset sulfate reduction and resultant metal-sulfide generation in ARD treatment can be enhanced by unravelling the complexities associated with these interactions. This research used material sourced from a passive bioreactor system located at the Stockton Coal Mine, New Zealand to investigate SRB activity and associated community function. RNA sequencing showed spore-forming Desulfitobacterium and Desulfotomaculum as the dominant SRB enriched from the reduced zone of the bioreactor. Metatranscriptomic analysis revealed acetogenic bacteria as syntrophic partners in substrate availability and Pseudomonas as metal-resistant community members. ZnS precipitates were observed by scanning electron microscopy (SEM) in short-term batch enrichments as well as long-term raw bioreactor material, with observed differences in mineral arrangement indicative of different nucleation scenarios. Syntrophy, metal response mechanisms, and the capacity for sporulation were observed as key microbial functions in mine waste reclamation settings. Here, Zn and S mass balance calculations coupled with RNA sequence data and microscopy illuminated favourable physicochemical and biological conditions for early metal sulfide precipitation in passive treatment systems for ARD and highlight the advantages of linking both lab and field-scale studies.

  17. Changes of Microbial Population in the Rumen of Dairy Steers as Influenced by Plant Containing Tannins and Saponins and Roughage to Concentrate Ratio

    Directory of Open Access Journals (Sweden)

    N. Anantasook

    2013-11-01

    Full Text Available The objective of this study was to investigate microbial population in the rumen of dairy steers as influenced by supplementing with dietary condensed tannins and saponins and different roughage to concentrate ratios. Four, rumen fistulated dairy steers (Bos indicus were used in a 2×2 factorial arrangement in a 4×4 Latin square design. The main factors were two roughage to concentrate ratios (R:C, 60:40 and 40:60 and two supplementations of rain tree pod meal (RPM (0 and 60 g/kg of total DM intake. Chopped 30 g/kg urea treated rice straw was used as a roughage source. All animals received feed according to respective R:C ratios at 25 g/kg body weight. The RPM contained crude tannins and saponins at 84 and 143 g/kg of DM, respectively. It was found that ruminal pH decreased while ruminal temperature increased by a higher concentrate ratio (R:C 40:60 (p<0.05. In contrast, total bacterial, Ruminococus albus and viable proteolytic bacteria were not affected by dietary supplementation. Numbers of fungi, cellulolytic bacteria, Fibrobactor succinogenes and Ruminococus flavefaciens were higher while amylolytic bacteria was lower when steers were fed at 400 g/kg of concentrate. The population of Fibrobactor succinogenes, was found to be higher with RPM supplementation. In addition, the use of real-time PCR technique indicated that the population of protozoa and methanogens were decreased (p<0.05 with supplementation of RPM and with an increasing concentrate ratio. Supplementation of RPM and feeding different concentrate ratios resulted in changing the rumen microbes especially, when the animals were fed at 600 g/kg of concentrate and supplemented with RPM which significantly reduced the protozoa and methanogens population.

  18. Effects of diets containing different concentrations of mannanoligosaccharide or antibiotics on growth performance, intestinal development, cecal and litter microbial populations, and carcass parameters of broilers.

    Science.gov (United States)

    Baurhoo, B; Ferket, P R; Zhao, X

    2009-11-01

    The effects of 2 levels of mannanoligosaccharide (MOS) in feed were compared with antibiotic growth promoters on growth performance, intestinal morphology, cecal and litter microbial populations, and carcass parameters in broilers raised in a sanitary environment. Dietary treatments included: 1) antibiotic growth promoter-free diet (control), 2) VIRG (diet 1 + 16.5 mg/kg of virginiamycin), 3) BACT (diet 1 + 55 mg/kg of bacitracin), 4) LMOS (diet 1 + 0.2% MOS), and 5) HMOS (diet 1 + 0.5% MOS). Birds were randomly assigned to 3 replicate pens/treatment (n = 55/pen). Body weight and feed intake were recorded weekly throughout 38 d. At d 14, 24, and 34, a 1-cm segment of duodenum, jejunum, and ileum was used in morphological analysis (n = 9 birds/d per treatment). At the same bird ages, cecal contents were assayed for lactobacilli, bifidobacteria, Salmonella, Campylobacter, and Escherichia coli, whereas litter was analyzed for Salmonella, Campylobacter, and E. coli. Carcass yields (breast fillet and tenders, thigh, drumstick, and wing) were determined at d 38. Body weight, feed conversion, and carcass yields did not differ among treatments. In contrast to birds fed VIRG or BACT, LMOS and HMOS consistently increased (P litter from all treatments were free of Salmonella. At d 14 and 24, cecal E. coli and Campylobacter counts were not different among treatments. In comparison to birds fed control, at d 34, BACT, LMOS, and HMOS significantly reduced (P Litter bacterial counts were not altered by dietary treatments. In conclusion, under conditions of this study, MOS conferred intestinal health benefits to chickens by improving its morphological development and microbial ecology. But, there were no additional benefits of the higher MOS dosage.

  19. Population dynamics and current-generation mechanisms in cassette-electrode microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kazuya [ERATO/JST, Tokyo (Japan). Hashimoto Light Energy Conversion Project; Tokyo Univ. (Japan). Research Center for Advanced Science and Technology; Tokyo Univ. of Pharmacy and Life Sciences (Japan). School of Life Sciences; Miyahara, Morio [ERATO/JST, Tokyo (Japan). Hashimoto Light Energy Conversion Project; Shimoyama, Takefumi [Tokyo Univ. (Japan). Research Center for Advanced Science and Technology; Hashimoto, Kazuhito [ERATO/JST, Tokyo (Japan). Hashimoto Light Energy Conversion Project; Tokyo Univ. (Japan). Dept. of Applied Chemistry

    2011-12-15

    Cassette-electrode microbial fuel cells (CE-MFCs) have been demonstrated useful to treat biomass wastes and recover electric energy from them. In order to reveal electricity-generation mechanisms in CE-MFCs, the present study operated a bench-scale reactor (1 l in capacity; approximately 1,000 cm{sup 2} in anode and cathode areas) for treating a high-strength model organic wastewater (comprised of starch, peptone, and fish extract). Approximately 1 month was needed for the bench reactor to attain a stable performance, after which volumetric maximum power densities persisted between 120 and 150 mW/l throughout the experiment (for over 2 months). Temporal increases in the external resistance were found to induce subsequent increases in power outputs. After electric output became stable, electrolyte and anode were sampled from the reactor for evaluating their current-generation abilities; it was estimated that most of current (over 80%) was generated by microbes in the electrolyte. Cyclic voltammetry of an electrolyte supernatant detected several electron shuttles with different standard redox potentials at high concentrations (equivalent to or more than 100 {mu}M 5-hydroxy-1,4-naphthoquinone). Denaturing gradient gel electrophoresis and quantitative real-time PCR of 16S ribosomal RNA gene fragments showed that bacteria related to the genus Dysgonomonas occurred abundantly in association with the increases in power outputs. These results suggest that mediated electron transfer was the main mechanism for electricity generation in CE-MFC, where high-concentration electron shuttles and Dysgonomonas bacteria played important roles. (orig.)

  20. Environmental whole-genome amplification to access microbial populations in contaminated sediments

    Energy Technology Data Exchange (ETDEWEB)

    Abulencia, Carl B [Diversa Corporation; Wyborski, Denise L. [Diversa Corporation; Garcia, Joseph A. [Diversa Corporation; Podar, Mircea [ORNL; Chen, Wenqiong [Diversa Corporation; Chang, Sherman H. [Diversa Corporation; Chang, Hwai W. [Diversa Corporation; Watson, David B [ORNL; Brodie, Eoin L. [Lawrence Berkeley National Laboratory (LBNL); Hazen, Terry [Lawrence Berkeley National Laboratory (LBNL); Keller, Martin [ORNL

    2006-05-01

    Low-biomass samples from nitrate and heavy metal contaminated soils yield DNA amounts that have limited use for direct, native analysis and screening. Multiple displacement amplification (MDA) using {phi}29 DNA polymerase was used to amplify whole genomes from environmental, contaminated, subsurface sediments. By first amplifying the genomic DNA (gDNA), biodiversity analysis and gDNA library construction of microbes found in contaminated soils were made possible. The MDA method was validated by analyzing amplified genome coverage from approximately five Escherichia coli cells, resulting in 99.2% genome coverage. The method was further validated by confirming overall representative species coverage and also an amplification bias when amplifying from a mix of eight known bacterial strains. We extracted DNA from samples with extremely low cell densities from a U.S. Department of Energy contaminated site. After amplification, small-subunit rRNA analysis revealed relatively even distribution of species across several major phyla. Clone libraries were constructed from the amplified gDNA, and a small subset of clones was used for shotgun sequencing. BLAST analysis of the library clone sequences showed that 64.9% of the sequences had significant similarities to known proteins, and 'clusters of orthologous groups' (COG) analysis revealed that more than half of the sequences from each library contained sequence similarity to known proteins. The libraries can be readily screened for native genes or any target of interest. Whole-genome amplification of metagenomic DNA from very minute microbial sources, while introducing an amplification bias, will allow access to genomic information that was not previously accessible.

  1. Effect of fermented feed on the microbial population of the gastrointestinal tracts of pigs

    NARCIS (Netherlands)

    Winsen, van R.L.; Urlings, B.A.P.; Lipman, L.J.A.; Snijders, J.M.A.; Keuzenkamp, D.; Verheijden, J.H.M.; Knapen, van F.

    2001-01-01

    An in vivo experiment was performed with pigs to study the inhibitory effect of fermented feed on the bacterial population of the gastrointestinal tract. Results demonstrated a significant positive correlation between pH and lactobacilli in the stomach contents of pigs in dry feed as well as in the

  2. Identification of active dehalorespiring microbial populations in anoxic river sediment by RNA-based stable isotope probing

    Science.gov (United States)

    Kittelmann, S.; Friedrich, M. W.

    2005-12-01

    Tetrachloroethene (perchloroethylene, PCE), a persistent contaminant in aquifers, soils and sediments, can be reductively dechlorinated by anaerobic microorganisms in a process referred to as dehalorespiration. However, the biodiversity of dehalorespiring microorganisms and their distribution especially in pristine environments is largely unexplored. Therefore, the aim of this study was to detect potentially novel PCE-dehalorespiring microorganisms by using stable isotope probing (SIP), a technique that allows to directly identify the function of uncultivated microbial populations. We simulated a PCE contamination by incubating pristine river sediment in the presence of PCE at a steady, low aqueous concentration (20 μM). Dehalogenation activity in microcosms (20 nmol cis-dichloroethene per ml slurry per day formed) was detected already after 4 weeks at 20°C with sediment indigenous electron donors. The microbial community in sediment incubations was probed with 13C-labelled acetate (0.5 mM) as electron donor and carbon source at 15°C for 3 days. After RNA extraction, "heavy" 13C-rRNA and light 12C-rRNA were separated by isopycnic centrifugation, and Bacteria-related populations in gradient fractions were characterised by terminal restriction fragment length polymorphism analysis and cloning. In heavy gradient fractions from the microcosm with PCE, we detected a prominent 506-bp terminal restriction fragment (T-RF) and a few minor T-RFs only. In contrast, in the control without PCE, Bacteria-specific rRNA was restricted to light gradient fractions, and the prominent T-RFs found in the PCE-dechlorinating microcosm were of minor importance. Apparently, 13C-acetate was incorporated into bacterial rRNA more effectively in PCE-respiring microcosms. Thus, rRNA-SIP provides strong evidence for the presence of PCE-dehalorespiring, 13C-acetate-utilising populations in river sediment microcosms. Cloning/sequencing analysis identified the prominent members of the heavy

  3. Metagenomic analysis of rumen microbial population in dairy heifers fed a high grain diet supplemented with dicarboxylic acids or polyphenols.

    Science.gov (United States)

    De Nardi, Roberta; Marchesini, Giorgio; Li, Shucong; Khafipour, Ehsan; Plaizier, Kees J C; Gianesella, Matteo; Ricci, Rebecca; Andrighetto, Igino; Segato, Severino

    2016-02-19

    The aim of this study was to investigate the effects of two feed supplements on rumen bacterial communities of heifers fed a high grain diet. Six Holstein-Friesian heifers received one of the following dietary treatments according to a Latin square design: no supplement (control, C), 60 g/day of fumarate-malate (organic acid, O) and 100 g/day of polyphenol-essential oil (P). Rumen fluid was analyzed to assess the microbial population using Illumina sequencing and quantitative real time PCR. The P treatment had the highest number of observed species (P PCoA with unweighted Unifrac distance showed a separation among dietary treatments (P = 0.09), above all between the C and P (P = 0.05). The O and P treatments showed a significant increase of the family Christenenellaceae and a decline of Prevotella brevis compared to C. Additionally, the P treatment enhanced the abundance of many taxa belonging to Bacteroidetes, Firmicutes and Tenericutes phyla due to a potential antimicrobial activity of flavonoids that increased competition among bacteria. Organic acid and polyphenols significantly modified rumen bacterial populations during high-grain feeding in dairy heifers. In particular the polyphenol treatment increased the richness and diversity of rumen microbiota, which are usually high in conditions of physiological rumen pH and rumen function.

  4. Microbial Ecophysiology of Whey Biomethanation: Characterization of Bacterial Trophic Populations and Prevalent Species in Continuous Culture

    OpenAIRE

    Chartrain, M.; Zeikus, J. G.

    1986-01-01

    The organization and species composition of bacterial trophic groups associated with lactose biomethanation were investigated in a whey-processing chemostat by enumeration, isolation, and general characterization studies. The bacteria were spatially organized as free-living forms and as self-immobilized forms appearing in flocs. Three dominant bacterial trophic group populations were present (in most probable number per milliliter) whose species numbers varied with the substrate consumed: hyd...

  5. Stratification of Microbial Processes and Populations in Biofilms Treating Pig Farm Waste Air

    DEFF Research Database (Denmark)

    Juhler, Susanne; Saunders, Aaron Marc; Pedersen, Kristina

    2006-01-01

    Biological air filters have been developed to reduce odor and ammonia emissions resulting from the rapidly expanding pig farm industry in many European countries. In contrast to aqueous biofilm environments, the biofilms of these filters are air-fed, allowing for extreme metabolite accumulation...

  6. Ecological feedbacks can reduce population-level efficacy of wildlife fertility control

    Science.gov (United States)

    Ransom, Jason I.; Powers, Jenny G.; Hobbs, N. Thompson; Baker, Dan L.

    2014-01-01

    1. Anthropogenic stress on natural systems, particularly the fragmentation of landscapes and the extirpation of predators from food webs, has intensified the need to regulate abundance of wildlife populations with management. Controlling population growth using fertility control has been considered for almost four decades, but nearly all research has focused on understanding effects of fertility control agents on individual animals. Questions about the efficacy of fertility control as a way to control populations remain largely unanswered. 2. Collateral consequences of contraception can produce unexpected changes in birth rates, survival, immigration and emigration that may reduce the effectiveness of regulating animal abundance. The magnitude and frequency of such effects vary with species-specific social and reproductive systems, as well as connectivity of populations. Developing models that incorporate static demographic parameters from populations not controlled by contraception may bias predictions of fertility control efficacy. 3. Many population-level studies demonstrate that changes in survival and immigration induced by fertility control can compensate for the reduction in births caused by contraception. The most successful cases of regulating populations using fertility control come from applications of contraceptives to small, closed populations of gregarious and easily accessed species. 4. Fertility control can result in artificial selection pressures on the population and may lead to long-term unintentional genetic consequences. The magnitude of such selection is dependent on individual heritability and behavioural traits, as well as environmental variation. 5. Synthesis and applications. Understanding species' life-history strategies, biology, behavioural ecology and ecological context is critical to developing realistic expectations of regulating populations using fertility control. Before time, effort and funding are invested in wildlife

  7. Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

    Science.gov (United States)

    Maltby, Johanna; Steinle, Lea; Löscher, Carolin R.; Bange, Hermann W.; Fischer, Martin A.; Schmidt, Mark; Treude, Tina

    2018-01-01

    Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority of methanogenesis is located below the sulfate-reducing zone, as sulfate reducers outcompete methanogens for the major substrates hydrogen and acetate. The coexistence of methanogenesis and sulfate reduction has been shown before and is possible through the usage of noncompetitive substrates by methanogens such as methanol or methylated amines. However, knowledge about the magnitude, seasonality, and environmental controls of this noncompetitive methane production is sparse. In the present study, the presence of methanogenesis within the sulfate reduction zone (SRZ methanogenesis) was investigated in sediments (0-30 cm below seafloor, cm b.s.f.) of the seasonally hypoxic Eckernförde Bay in the southwestern Baltic Sea. Water column parameters such as oxygen, temperature, and salinity together with porewater geochemistry and benthic methanogenesis rates were determined in the sampling area Boknis Eck quarterly from March 2013 to September 2014 to investigate the effect of seasonal environmental changes on the rate and distribution of SRZ methanogenesis, to estimate its potential contribution to benthic methane emissions, and to identify the potential methanogenic groups responsible for SRZ methanogenesis. The metabolic pathway of methanogenesis in the presence or absence of sulfate reducers, which after the addition of a noncompetitive substrate was studied in four experimental setups: (1) unaltered sediment batch incubations (net methanogenesis), (2) 14C-bicarbonate labeling experiments (hydrogenotrophic methanogenesis), (3) manipulated experiments with the addition of either molybdate (sulfate reducer inhibitor), 2-bromoethanesulfonate (methanogen inhibitor), or methanol (noncompetitive substrate, potential methanogenesis), and (4) the addition of 13C-labeled methanol (potential methylotrophic methanogenesis). After incubation with methanol, molecular

  8. Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

    Directory of Open Access Journals (Sweden)

    J. Maltby

    2018-01-01

    Full Text Available Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority of methanogenesis is located below the sulfate-reducing zone, as sulfate reducers outcompete methanogens for the major substrates hydrogen and acetate. The coexistence of methanogenesis and sulfate reduction has been shown before and is possible through the usage of noncompetitive substrates by methanogens such as methanol or methylated amines. However, knowledge about the magnitude, seasonality, and environmental controls of this noncompetitive methane production is sparse. In the present study, the presence of methanogenesis within the sulfate reduction zone (SRZ methanogenesis was investigated in sediments (0–30 cm below seafloor, cm b.s.f. of the seasonally hypoxic Eckernförde Bay in the southwestern Baltic Sea. Water column parameters such as oxygen, temperature, and salinity together with porewater geochemistry and benthic methanogenesis rates were determined in the sampling area Boknis Eck quarterly from March 2013 to September 2014 to investigate the effect of seasonal environmental changes on the rate and distribution of SRZ methanogenesis, to estimate its potential contribution to benthic methane emissions, and to identify the potential methanogenic groups responsible for SRZ methanogenesis. The metabolic pathway of methanogenesis in the presence or absence of sulfate reducers, which after the addition of a noncompetitive substrate was studied in four experimental setups: (1 unaltered sediment batch incubations (net methanogenesis, (2 14C-bicarbonate labeling experiments (hydrogenotrophic methanogenesis, (3 manipulated experiments with the addition of either molybdate (sulfate reducer inhibitor, 2-bromoethanesulfonate (methanogen inhibitor, or methanol (noncompetitive substrate, potential methanogenesis, and (4 the addition of 13C-labeled methanol (potential methylotrophic methanogenesis. After incubation with

  9. Cropping Effects on Microbial Population and Nitrogenase Activity in Saline Arid Soil

    OpenAIRE

    EGAMBERDIEVA, Dilfuza; KUCHAROVA, Zulfiya

    2008-01-01

    Soil salinization is a major problem in irrigated agriculture. A field study was conducted in the Sariosiyo district in the Surkhandarya region of southeast Uzbekistan to evaluate soil nitrogenase activity and nitrogen-fixing bacteria populations in saline serozem soils under wheat, maize, and alfalfa, as well as from adjacent fallow land. Composite soil samples were randomly collected from depths of 0-10, 10-20, and 20-30 cm in autumn, winter, spring, and summer, which were then 2-mm sieved ...

  10. How often do they have sex? A comparative analysis of the population structure of seven eukaryotic microbial pathogens.

    Directory of Open Access Journals (Sweden)

    Nicolás Tomasini

    Full Text Available The model of predominant clonal evolution (PCE proposed for micropathogens does not state that genetic exchange is totally absent, but rather, that it is too rare to break the prevalent PCE pattern. However, the actual impact of this "residual" genetic exchange should be evaluated. Multilocus Sequence Typing (MLST is an excellent tool to explore the problem. Here, we compared online available MLST datasets for seven eukaryotic microbial pathogens: Trypanosoma cruzi, the Fusarium solani complex, Aspergillus fumigatus, Blastocystis subtype 3, the Leishmania donovani complex, Candida albicans and Candida glabrata. We first analyzed phylogenetic relationships among genotypes within each dataset. Then, we examined different measures of branch support and incongruence among loci as signs of genetic structure and levels of past recombination. The analyses allow us to identify three types of genetic structure. The first was characterized by trees with well-supported branches and low levels of incongruence suggesting well-structured populations and PCE. This was the case for the T. cruzi and F. solani datasets. The second genetic structure, represented by Blastocystis spp., A. fumigatus and the L. donovani complex datasets, showed trees with weakly-supported branches but low levels of incongruence among loci, whereby genetic structuration was not clearly defined by MLST. Finally, trees showing weakly-supported branches and high levels of incongruence among loci were observed for Candida species, suggesting that genetic exchange has a higher evolutionary impact in these mainly clonal yeast species. Furthermore, simulations showed that MLST may fail to show right clustering in population datasets even in the absence of genetic exchange. In conclusion, these results make it possible to infer variable impacts of genetic exchange in populations of predominantly clonal micro-pathogens. Moreover, our results reveal different problems of MLST to determine the

  11. Degradation of hazardous chemicals in liquid radioactive wastes from biomedical research using a mixed microbial population

    International Nuclear Information System (INIS)

    Wolfram, J.H.; Radtke, M.; Wey, J.E.; Rogers, R.D.; Rau, E.H.

    1997-10-01

    As the costs associated with treatment of mixed wastes by conventional methods increase, new technologies will be investigated as alternatives. This study examines the potential of using a selected mixed population of microorganisms to treat hazardous chemical compounds in liquid low level radioactive wastes from biomedical research procedures. Microorganisms were isolated from various waste samples and enriched against compounds known to occur in the wastes. Individual isolates were tested for their ability to degrade methanol, ethanol, phenol, toluene, phthalates, acetonitrile, chloroform, and trichloroacetic acid. Following these tests, the organisms were combined in a media with a mixture of the different compounds. Three compounds: methanol, acetonitrile, and pseudocumene, were combined at 500 microliter/liter each. Degradation of each compound was shown to occur (75% or greater) under batch conditions with the mixed population. Actual wastes were tested by adding an aliquot to the media, determining the biomass increase, and monitoring the disappearance of the compounds. The compounds in actual waste were degraded, but at different rates than the batch cultures that did not have waste added. The potential of using bioprocessing methods for treating mixed wastes from biomedical research is discussed

  12. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN

    Directory of Open Access Journals (Sweden)

    Penny Lea Morrill

    2014-11-01

    Full Text Available Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in 13 C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ13C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  13. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

    Science.gov (United States)

    Morrill, Penny L; Brazelton, William J; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M; Kavanagh, Heidi; Schrenk, Matthew O; Ziegler, Susan E; Lang, Susan Q

    2014-01-01

    Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  14. Surveillance study of bacterial contamination of the parent's cell phone in the NICU and the effectiveness of an anti-microbial gel in reducing transmission to the hands.

    Science.gov (United States)

    Beckstrom, A C; Cleman, P E; Cassis-Ghavami, F L; Kamitsuka, M D

    2013-12-01

    To determine the bacterial contamination rate of the parent's cell phone and the effectiveness of anti-microbial gel in reducing transmission of bacteria from cell phone to hands. Cross-sectional study of cultures from the cell phone and hands before and after applying anti-microbial gel (n=50). All cell phones demonstrated bacterial contamination. Ninety percent had the same bacteria on the cell phone and their cleaned hands. Twenty two percent had no growth on their hands after applying anti-microbial gel after they had the same bacteria on the cell phone and hands. Ninety-two percent of parents were aware that cell phones carried bacteria, but only 38% cleaned their cell phones at least weekly. Bacterial contamination of cell phones may serve as vectors for nosocomial infection in the neonatal intensive care unit. Bacteria transmitted from cell phone to hands may not be eliminated using anti-microbial gel. Development of hand hygiene and cell phone cleaning guidelines are needed regarding bedside cell phone use.

  15. Effects of reduced-impact logging and forest physiognomy on bat populations of lowland Amazonian forest.

    Science.gov (United States)

    Steven J. Presley; Michael R. Willig; Wunderle Jr. Joseph M.; Luis Nélio. Saldanha

    2008-01-01

    1.As human population size increases, demand for natural resources will increase. Logging pressure related to increasing demands continues to threaten remote areas of Amazonian forest. A harvest protocol is required to provide renewable timber resources that meet consumer needs while minimizing negative effects on biodiversity and ecosystem services. Reduced-impact...

  16. Statins reduce new-onset atrial fibrillation in a first-time myocardial infarction population

    DEFF Research Database (Denmark)

    Bang, Casper N; Gislason, Gunnar H; Greve, Anders M

    2014-01-01

    AIM: To evaluate the effect of statins on reducing new-onset atrial fibrillation (AF) in a large real-world post-myocardial infarction (MI) population. Subsequently, to test if different statin doses, various types and compliance affected the incidence of new-onset AF post MI. METHODS: All patients...

  17. A pilot-scale nonwoven roll goods manufacturing process reduces microbial burden to pharmacopeia acceptance levels for nonsterile hygiene applications

    Science.gov (United States)

    A total of seven source fiber types were selected for use in the manufacturing of nonwoven roll goods: polyester; polypropylene; rayon; greige cotton from two sources; mechanically cleaned greige cotton; and scoured and bleached cotton. The microbial burden of each source fiber was measured as a pr...

  18. Significant Association between Sulfate-Reducing Bacteria and Uranium-Reducing Microbial Communities as Revealed by a Combined Massively Parallel Sequencing-Indicator Species Approach▿ †

    OpenAIRE

    Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K.; Jardine, Philip M.; Zhou, Jizhong; Criddle, Craig S.; Marsh, Terence L.

    2010-01-01

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remedi...

  19. Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth.

    Science.gov (United States)

    Martínez, M E; Ranilla, M J; Tejido, M L; Ramos, S; Carro, M D

    2010-08-01

    Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of forage to concentrate (F:C) ratio and type of forage in the diet on ruminal fermentation and microbial protein synthesis. The purpose of the study was to assess how closely fermenters can mimic the dietary differences found in vivo. The 4 experimental diets contained F:C ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Microbial growth was determined in both systems using (15)N as a microbial marker. Rusitec fermenters detected differences between diets similar to those observed in sheep by changing F:C ratio on pH; neutral detergent fiber digestibility; total volatile fatty acid concentrations; molar proportions of acetate, propionate, butyrate, isovalerate, and caproate; and amylase activity. In contrast, Rusitec fermenters did not reproduce the dietary differences found in sheep for NH(3)-N and lactate concentrations, dry matter (DM) digestibility, proportions of isobutyrate and valerate, carboxymethylcellulase and xylanase activities, and microbial growth and its efficiency. Regarding the effect of the type of forage in the diet, Rusitec fermenters detected differences between diets similar to those found in sheep for most determined parameters, with the exception of pH, DM digestibility, butyrate proportion, and carboxymethylcellulase activity. Minimum pH and maximal volatile fatty acid concentrations were reached at 2h and at 6 to 8h postfeeding in sheep and fermenters, respectively, indicating that feed fermentation was slower in fermenters compared with that in sheep. There were differences between systems in the magnitude of most determined parameters. In general, fermenters showed lower lactate concentrations, neutral detergent fiber digestibility, acetate:propionate ratios, and enzymatic activities. On the contrary, fermenters showed greater NH(3)-N concentrations, DM digestibility, and proportions of propionate

  20. Modeling of Nonlinear Dynamics and Synchronized Oscillations of Microbial Populations, Carbon and Oxygen Concentrations, Induced by Root Exudation in the Rhizosphere

    Science.gov (United States)

    Molz, F. J.; Faybishenko, B.; Jenkins, E. W.

    2012-12-01

    Mass and energy fluxes within the soil-plant-atmosphere continuum are highly coupled and inherently nonlinear. The main focus of this presentation is to demonstrate the results of numerical modeling of a system of 4 coupled, nonlinear ordinary differential equations (ODEs), which are used to describe the long-term, rhizosphere processes of soil microbial dynamics, including the competition between nitrogen-fixing bacteria and those unable to fix nitrogen, along with substrate concentration (nutrient supply) and oxygen concentration. Modeling results demonstrate the synchronized patterns of temporal oscillations of competing microbial populations, which are affected by carbon and oxygen concentrations. The temporal dynamics and amplitude of the root exudation process serve as a driving force for microbial and geochemical phenomena, and lead to the development of the Gompetzian dynamics, synchronized oscillations, and phase-space attractors of microbial populations and carbon and oxygen concentrations. The nonlinear dynamic analysis of time series concentrations from the solution of the ODEs was used to identify several types of phase-space attractors, which appear to be dependent on the parameters of the exudation function and Monod kinetic parameters. This phase space analysis was conducted by means of assessing the global and local embedding dimensions, correlation time, capacity and correlation dimensions, and Lyapunov exponents of the calculated model variables defining the phase space. Such results can be used for planning experimental and theoretical studies of biogeochemical processes in the fields of plant nutrition, phyto- and bio-remediation, and other ecological areas.

  1. Patterns of ecological specialization among microbial populations in the Red Sea and diverse oligotrophic marine environments.

    Science.gov (United States)

    Thompson, Luke R; Field, Chris; Romanuk, Tamara; Ngugi, David; Siam, Rania; El Dorry, Hamza; Stingl, Ulrich

    2013-06-01

    Large swaths of the nutrient-poor surface ocean are dominated numerically by cyanobacteria (Prochlorococcus), cyanobacterial viruses (cyanophage), and alphaproteobacteria (SAR11). How these groups thrive in the diverse physicochemical environments of different oceanic regions remains poorly understood. Comparative metagenomics can reveal adaptive responses linked to ecosystem-specific selective pressures. The Red Sea is well-suited for studying adaptation of pelagic-microbes, with salinities, temperatures, and light levels at the extreme end for the surface ocean, and low nutrient concentrations, yet no metagenomic studies have been done there. The Red Sea (high salinity, high light, low N and P) compares favorably with the Mediterranean Sea (high salinity, low P), Sargasso Sea (low P), and North Pacific Subtropical Gyre (high light, low N). We quantified the relative abundance of genetic functions among Prochlorococcus, cyanophage, and SAR11 from these four regions. Gene frequencies indicate selection for phosphorus acquisition (Mediterranean/Sargasso), DNA repair and high-light responses (Red Sea/Pacific Prochlorococcus), and osmolyte C1 oxidation (Red Sea/Mediterranean SAR11). The unexpected connection between salinity-dependent osmolyte production and SAR11 C1 metabolism represents a potentially major coevolutionary adaptation and biogeochemical flux. Among Prochlorococcus and cyanophage, genes enriched in specific environments had ecotype distributions similar to nonenriched genes, suggesting that inter-ecotype gene transfer is not a major source of environment-specific adaptation. Clustering of metagenomes using gene frequencies shows similarities in populations (Red Sea with Pacific, Mediterranean with Sargasso) that belie their geographic distances. Taken together, the genetic functions enriched in specific environments indicate competitive strategies for maintaining carrying capacity in the face of physical stressors and low nutrient availability.

  2. Influence of erythromycin A on the microbial populations in aquaculture sediment microcosms

    International Nuclear Information System (INIS)

    Kim, Yong-Hak; Cerniglia, Carl E.

    2005-01-01

    Degradation of erythromycin A was studied using two sediment samples obtained from the salmon and trout hatchery sites at Hupp Springs (HS) and Goldendale (GD), Washington, United States. The former site had been treated for 3 years with erythromycin-medicated feed prior to the experiments, and the latter site had not been treated with any antibiotic for at least 6 years. The two sediment microcosms treated with either N-[methyl- 14 C]erythromycin A or [1,3,5,7,9,11,13- 14 C]erythromycin A showed S-curves for erythromycin A mineralization with a prolonged lag time of 120 days, except for GD microcosms treated with [1,3,5,7,9,11,13- 14 C]erythromycin A. We proposed a simplified logistic model to interpret the mineralization curves under the assumption of the low densities of initial populations metabolizing erythromycin A. The model was helpful for knowing the biological potential for erythromycin A degradation in sediments. Although erythromycin A added to the two sediment microcosms did not significantly alter the numbers of total viable aerobic bacteria or erythromycin-resistant bacteria, it affected the bacterial composition. The influence on the bacterial composition appeared to be greater in GD microcosms without pre-exposure to antibiotics. PCR-RFLP and DNA sequence analyses of the 16S ribosomal RNA gene and the erythromycin esterase (ere) gene revealed that ereA type 2 (ereA2) was present in potentially erythromycin-degrading Pseudomonas spp. strains GD100, GD200, HS100, HS200 and HS300, isolated from erythromycin-treated and non-treated GD and HS microcosms. Erythromycin A appeared to influence the development and proliferation of strain GD200, possibly via the lateral gene transfer of ereA2

  3. Influence of erythromycin A on the microbial populations in aquaculture sediment microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong-Hak [Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States)]. E-mail: yhkim660628@hotmail.com; Cerniglia, Carl E. [Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States)]. E-mail: ccerniglia@nctr.fda.gov

    2005-07-01

    Degradation of erythromycin A was studied using two sediment samples obtained from the salmon and trout hatchery sites at Hupp Springs (HS) and Goldendale (GD), Washington, United States. The former site had been treated for 3 years with erythromycin-medicated feed prior to the experiments, and the latter site had not been treated with any antibiotic for at least 6 years. The two sediment microcosms treated with either N-[methyl-{sup 14}C]erythromycin A or [1,3,5,7,9,11,13-{sup 14}C]erythromycin A showed S-curves for erythromycin A mineralization with a prolonged lag time of 120 days, except for GD microcosms treated with [1,3,5,7,9,11,13-{sup 14}C]erythromycin A. We proposed a simplified logistic model to interpret the mineralization curves under the assumption of the low densities of initial populations metabolizing erythromycin A. The model was helpful for knowing the biological potential for erythromycin A degradation in sediments. Although erythromycin A added to the two sediment microcosms did not significantly alter the numbers of total viable aerobic bacteria or erythromycin-resistant bacteria, it affected the bacterial composition. The influence on the bacterial composition appeared to be greater in GD microcosms without pre-exposure to antibiotics. PCR-RFLP and DNA sequence analyses of the 16S ribosomal RNA gene and the erythromycin esterase (ere) gene revealed that ereA type 2 (ereA2) was present in potentially erythromycin-degrading Pseudomonas spp. strains GD100, GD200, HS100, HS200 and HS300, isolated from erythromycin-treated and non-treated GD and HS microcosms. Erythromycin A appeared to influence the development and proliferation of strain GD200, possibly via the lateral gene transfer of ereA2.

  4. Patterns of ecological specialization among microbial populations in the Red Sea and diverse oligotrophic marine environments

    KAUST Repository

    Thompson, Luke R

    2013-05-11

    Large swaths of the nutrient-poor surface ocean are dominated numerically by cyanobacteria (Prochlorococcus), cyanobacterial viruses (cyanophage), and alphaproteobacteria (SAR11). How these groups thrive in the diverse physicochemical environments of different oceanic regions remains poorly understood. Comparative metagenomics can reveal adaptive responses linked to ecosystem-specific selective pressures. The Red Sea is well-suited for studying adaptation of pelagic-microbes, with salinities, temperatures, and light levels at the extreme end for the surface ocean, and low nutrient concentrations, yet no metagenomic studies have been done there. The Red Sea (high salinity, high light, low N and P) compares favorably with the Mediterranean Sea (high salinity, low P), Sargasso Sea (low P), and North Pacific Subtropical Gyre (high light, low N). We quantified the relative abundance of genetic functions among Prochlorococcus, cyanophage, and SAR11 from these four regions. Gene frequencies indicate selection for phosphorus acquisition (Mediterranean/Sargasso), DNA repair and high-light responses (Red Sea/Pacific Prochlorococcus), and osmolyte C1 oxidation (Red Sea/Mediterranean SAR11). The unexpected connection between salinity-dependent osmolyte production and SAR11 C1 metabolism represents a potentially major coevolutionary adaptation and biogeochemical flux. Among Prochlorococcus and cyanophage, genes enriched in specific environments had ecotype distributions similar to nonenriched genes, suggesting that inter-ecotype gene transfer is not a major source of environment-specific adaptation. Clustering of metagenomes using gene frequencies shows similarities in populations (Red Sea with Pacific, Mediterranean with Sargasso) that belie their geographic distances. Taken together, the genetic functions enriched in specific environments indicate competitive strategies for maintaining carrying capacity in the face of physical stressors and low nutrient availability. 2013 The

  5. Effect of adding herbs (Ziziphora clinopodioides, Mentha spicata and Mentha pulegium in milk on performance, blood metabolites and fecal microbial population on Holstein calves

    Directory of Open Access Journals (Sweden)

    narges ghahhari

    2016-08-01

    Full Text Available Introduction Many herbal products (herbs and essential oils are currently used as feed additives by the feed industry in the European Union and elsewhere. These phytogenic substances which increase feed aroma or palatability of feeds are classified as sensory additives by European Council. However, several publications show that some essential oils may have beneficial effects on animal performance and health status because of other properties except their sensory characteristics. These claimed properties are stimulation of digestive secretions; antimicrobial, coccidiostat, anthelmintic, and anti-inflammatory activities; and antioxidant properties. Most research revealed that supplementing herbal essential oils to diets resulted in reducing blood cholesterol, increasing palatability of feed and stimulating the immune system in poultry, while different results obtained by ruminants because of rumen microbial population and ruminal fermentation conditions. The use of large and repeated quantities of antibiotics in animal feed may cause to eliminate beneficial intestinal microflora and innate immune system and subsequently cause to antibiotic resistance and remains antibiotics in animal products. Recently, many herbal products because having flavoring and antimicrobial properties as introduced as good alternatives for antibiotics. The aim of the present investigation was to study of effect of Ziziphora clinopodioies, Mentha spicata and Mentha pulegium on the performance of suckling calves, dry matter digestibility, blood parameters and the immune system, the effect on the incidence of diarrhea and fecal microbial population (Escherichia coli, lactobacillus and total aerobic bacteria. Materials and Methods In the present study, extraction of essential oils from three plant species (Ziziphora clinopodioies, Mentha spicata and Mentha pulegium by means of gas chromatography coupled to mass spectrometry (GC–MS were analyzed. In order to determine the

  6. Taxonomic structure and population level of colon microbial contents in white rats with experimental thyrotoxicosis

    Directory of Open Access Journals (Sweden)

    L.I. Sydorchuk

    2017-08-01

    Full Text Available Background. Production of numerous biologically active compounds and their metabolites by intestinal microflora, interaction with the immune and other systems is of great importance while studying its changes in various diseases, one of which is thyrotoxicosis. So, the purpose of this study was to determine the severity of intestine microbioma disorder in white rats with experimental thyrotoxicosis (ET. Materials and methods. Studies were carried out on 25 mature male white rats (15 — control group, 10 — research group. ET was simulated by intragastric administration of L-thyroxine for 14 days. Under sterile conditions a laparotomy was performed, a section (2–3 cm of the large intestine with its contents was taken. Sterile 0.9% NaCl solution was added to the content. Series of ten-fold dilutions with a concentration of the initial mixture of 10–2 to 10–11 was prepared. From each test tube 0.01 ml was seeded on solid nutrient media with subsequent isolation and identification of microbes according to morphological, tinctorial, cultural and biochemical properties. Results. The results of the study demonstrated that in ET animals the main microbioma is represented by bacteria Bifidobacterium, Lactobacillus, Bacteroides, and also opportunistic enterobacteria (Escherichia, Proteus, Klebsiella, peptococcus, staphylococci and clostridia. This is accompanied by the elimination of Peptostreptococcus, Enterococcus from bacterial biotope and the contamination of K. oxytoca and staphylococci. There was a pronounced deficit of bifidobacteria by 42.81 %, lactobacillus by 22.57 %, normal intestinal bacillus by 16.48 %. By the population level, the coefficient of quantitative dominance and the significance factor, the leading place is occupied by bacteroids, role of which is increased by 21.72 %, and lactobacillus role decreases by 39.31 %, bifidobacteria decreases by 51.48 % and E. coli decreases by 57.49 %. In this case, the role of peptococcus 3

  7. Microbial electrosynthetic cells

    Energy Technology Data Exchange (ETDEWEB)

    May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

    2018-01-30

    Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

  8. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    International Nuclear Information System (INIS)

    Lee, Duu-Jong; Lee, Chin-Yu; Chang, Jo-Shu

    2012-01-01

    Highlights: ► We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. ► Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. ► The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. ► The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  9. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Duu-Jong, E-mail: cedean@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan (China); Lee, Chin-Yu [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. Black-Right-Pointing-Pointer Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. Black-Right-Pointing-Pointer The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. Black-Right-Pointing-Pointer The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  10. Reduced Variance of Gene Expression at Numerous Loci in a Population of Chickens Selected for High Feather Pecking

    DEFF Research Database (Denmark)

    Hughes, A L; Buitenhuis, A J

    2010-01-01

    among populations with respect to mean expression scores, but numerous transcripts showed reduced variance in expression scores in the high FP population in comparison to control and low FP populations. The reduction in variance in the high FP population generally involved transcripts whose expression...

  11. Diminished UV-absorbing nets reduce the Spreads and population density of Macrosiphum euphorbiae in lettuce.

    OpenAIRE

    Legarrea, S.; Díaz, B. M.; Plaza, M.; Barrios, L.; Morales, Ignacio; Viñuela Sandoval, Elisa; Fereres Castiel, Alberto

    2012-01-01

    UV-absorbing covers reduce the incidence of injurious insect pests and viruses in protected crops. In the present study, the effect of a UV-absorbing net (Bionet) on the spatio-temporal dynamics of the potato aphid on lettuce plants was evaluated. A field experiment was conducted during three seasons in two identical tunnels divided in four plots. A set of lettuce plants were artificially infested with Macrosiphum euphorbiae adults and the population was estimated by counting aphids on ev...

  12. Methyl salicylate attracts natural enemies and reduces populations of soybean aphids (Hemiptera: Aphididae) in soybean agroecosystems.

    Science.gov (United States)

    Mallinger, Rachel E; Hogg, David B; Gratton, Claudio

    2011-02-01

    Methyl salicylate, an herbivore-induced plant volatile, has been shown to attract natural enemies and affect herbivore behavior. In this study, methyl salicylate was examined for its attractiveness to natural enemies of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and for its direct effects on soybean aphid population growth rates. Methyl salicylate lures were deployed in plots within organic soybean [Glycine max (L.) Merr.] fields. Sticky card traps adjacent to and 1.5 m from the lure measured the relative abundance of natural enemies, and soybean aphid populations were monitored within treated and untreated plots. In addition, exclusion cage studies were conducted to determine methyl salicylate's effect on soybean aphid population growth rates in the absence of natural enemies. Significantly greater numbers of syrphid flies (Diptera: Syrphidae) and green lacewings (Neuroptera: Chrysopidae) were caught on traps adjacent to the methyl salicylate lure, but no differences in abundance were found at traps 1.5 m from the lure. Furthermore, abundance of soybean aphids was significantly lower in methyl salicylate-treated plots. In exclusion cage studies, soybean aphid numbers were significantly reduced on treated soybean plants when all plants were open to natural enemies. When plants were caged, however, soybean aphid numbers and population growth rates did not differ between treated and untreated plants suggesting no effect of methyl salicylate on soybean aphid reproduction and implicating the role of natural enemies in depressing aphid populations. Although aphid populations were reduced locally around methyl salicylate lures, larger scale studies are needed to assess the technology at the whole-field scale.

  13. A reduced number of mtSNPs saturates mitochondrial DNA haplotype diversity of worldwide population groups.

    Science.gov (United States)

    Salas, Antonio; Amigo, Jorge

    2010-05-03

    The high levels of variation characterising the mitochondrial DNA (mtDNA) molecule are due ultimately to its high average mutation rate; moreover, mtDNA variation is deeply structured in different populations and ethnic groups. There is growing interest in selecting a reduced number of mtDNA single nucleotide polymorphisms (mtSNPs) that account for the maximum level of discrimination power in a given population. Applications of the selected mtSNP panel range from anthropologic and medical studies to forensic genetic casework. This study proposes a new simulation-based method that explores the ability of different mtSNP panels to yield the maximum levels of discrimination power. The method explores subsets of mtSNPs of different sizes randomly chosen from a preselected panel of mtSNPs based on frequency. More than 2,000 complete genomes representing three main continental human population groups (Africa, Europe, and Asia) and two admixed populations ("African-Americans" and "Hispanics") were collected from GenBank and the literature, and were used as training sets. Haplotype diversity was measured for each combination of mtSNP and compared with existing mtSNP panels available in the literature. The data indicates that only a reduced number of mtSNPs ranging from six to 22 are needed to account for 95% of the maximum haplotype diversity of a given population sample. However, only a small proportion of the best mtSNPs are shared between populations, indicating that there is not a perfect set of "universal" mtSNPs suitable for all population contexts. The discrimination power provided by these mtSNPs is much higher than the power of the mtSNP panels proposed in the literature to date. Some mtSNP combinations also yield high diversity values in admixed populations. The proposed computational approach for exploring combinations of mtSNPs that optimise the discrimination power of a given set of mtSNPs is more efficient than previous empirical approaches. In contrast to

  14. Quantification of Functional Marker Genes for Denitrifying Microbial Populations in the Chandeleur Islands Impacted by the 2010 Gulf of Mexico Oil Spill

    Science.gov (United States)

    Crawford, P.; Flournoy, N.; Taylor, C.; Tatariw, C.; Mortazavi, B.; Sobecky, P.

    2017-12-01

    Barrier island ecosystems provide protection by reducing storm surges, dissipating wave energy, and economically through services such as fisheries, water catchment, and water quality. As these ecosystems are deteriorating and threatened in this century, services provided to humans are being valued monetarily to communicate their importance. Events such as the 2010 Gulf of Mexico oil spill, act as catalysts to accelerate deterioration and further loss of these vital ecosystem services. The oil spill impacted the Chandeleur Islands, barrier islands in Louisiana waters located forty miles south of Gulfport, MS. Island chain vegetation; i.e., Avicennia germinans and native Spartina alterniflora was heavily damaged as a result of the oil spill. As oil was deposited differentially, it was important to investigate the microbiology of oil-impacted areas as marsh vegetation is directly linked to microbe-driven ecosystem services such as denitrification, a nitrogen (N) cycle pathway. The objectives of this study were: i) characterize the biodiversity of microorganisms; ii) quantify denitrifying microbial populations using functional marker genes; and iii) measure rates of denitrification during a one-year period. Eco-functional marker genes narG, nirS, norB, nosZ, and nrfA were selected to represent denitrification. Three different marsh sites were selected for study based upon estimated amounts of prior oiling. Highest rates of denitrification were in September while the lowest rates were observed in February. The highest nirS abundance was detected for two of the three sites (Site 1 and 2) in September while Site 3 exhibited the highest abundance in November. Similarly, the highest abundances observed for norB and nosZ varied by site and by month. Weathered oil was also detected in some of the marsh sediment cores and chemically typed to Macondo oil. Studies such as this one are designed to characterize the barrier island microbial biodiversity and N cycle processes to

  15. [Dynamic changes of soil microbial populations and enzyme activities in super-high yielding summer maize farmland soil].

    Science.gov (United States)

    Hou, Peng; Wang, Yong-jun; Wang, Kong-jun; Yang, Jin-sheng; Li, Deng-hai; Dong, Shu-ting; Liu, Jing-guo

    2008-08-01

    To reveal the characteristics of the dynamic changes of soil microbial populations and enzyme activities in super-high yielding ( > 15,000 kg x hm(-2)) summer maize farmland soil, a comparative study was conducted in the experimental fields in National Maize Engineering Research Center (Shandong). On the fields with an annual yield of >15,000 kg x hm(-2) in continuous three years, a plot with the yield of 20 322 kg x hm(-2) (HF) was chosen to make comparison with the conventional farmland (CF) whose maize yield was 8920. 1 kg x hm(-2). The numbers of bacteria, fungi, and actinomycetes as well as the activities of urease and invertase in 0-20 cm soil layer were determined. The results showed that in the growth period of maize, the numbers of bacteria, fungi, and actinomycetes in the two farmland soils increased first and declined then. At the later growth stages of maize, the numbers of soil microbes, especially those of bacteria and actinomycetes, were lower in HF than those in CF. At harvest stage, the ratio of the number of soil bacteria to fungi (B/ F) in HF was 2.03 times higher than that at sowing stage, and 3.02 times higher than that in CF. The B/F in CF had less difference at harvest and sowing stages. The soil urease activity in HF was significantly lower than that in CF at jointing stage, and the invertase activity in HF decreased rapidly after blooming stage, being significantly lower than that in CF.

  16. Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. II. Protozoa population and diversity of bacterial communities.

    Science.gov (United States)

    Martínez, M E; Ranilla, M J; Tejido, M L; Saro, C; Carro, M D

    2010-08-01

    Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of dietary characteristics on microbial populations and bacterial diversity. The purpose of the study was to assess how closely fermenters can mimic the differences between diets found in vivo. The 4 experimental diets contained forage to concentrate (F:C) ratios of 70:30 (high forage; HF) or 30:70 (high concentrate; HC) with either alfalfa hay (A) or grass hay (G) as the forage. Total bacterial numbers were greater in the rumen of sheep fed HF diets compared with those fed HC diets, whereas the opposite was found in fermenters. The numbers of cellulolytic bacteria were not affected by F:C ratio in any fermentation system, but cellulolytic numbers were 2.7 and 1.8 times greater in sheep than in fermenters for HF and HC diets, respectively. Neither total bacterial nor cellulolytic numbers were affected by the type of forage in sheep or fermenters. Decreasing F:C ratio increased total protozoa and Entodiniae numbers in sheep by about 29 and 25%, respectively, but it had no effect in fermenters. Isotrichidae and Ophryoscolecinae numbers in sheep were not affected by changing F:C ratio, but both disappeared completely from fermenters fed HC diets. Total protozoa and Entodiniae numbers were greater in sheep fed A diets than in those fed G diets, whereas the opposite was found in fermenters. Results indicate that under the conditions of the present study, protozoa population in Rusitec fermenters was not representative of that in the rumen of sheep fed the same diets. In addition, protozoa numbers in fermenters were 121 and 226 times lower than those in the sheep rumen for HF and HC diets, respectively. The automated ribosomal intergenic spacer analysis of the 16S ribosomal DNA was used to analyze the diversity of liquid- and solid-associated bacteria in both systems. A total of 170 peaks were detected in the automated ribosomal intergenic spacer analysis

  17. Characterization of microbial associations with methanotrophic archaea and sulfate-reducing bacteria through statistical comparison of nested Magneto-FISH enrichments

    Directory of Open Access Journals (Sweden)

    Elizabeth Trembath-Reichert

    2016-04-01

    Full Text Available Methane seep systems along continental margins host diverse and dynamic microbial assemblages, sustained in large part through the microbially mediated process of sulfate-coupled Anaerobic Oxidation of Methane (AOM. This methanotrophic metabolism has been linked to consortia of anaerobic methane-oxidizing archaea (ANME and sulfate-reducing bacteria (SRB. These two groups are the focus of numerous studies; however, less is known about the wide diversity of other seep associated microorganisms. We selected a hierarchical set of FISH probes targeting a range of Deltaproteobacteria diversity. Using the Magneto-FISH enrichment technique, we then magnetically captured CARD-FISH hybridized cells and their physically associated microorganisms from a methane seep sediment incubation. DNA from nested Magneto-FISH experiments was analyzed using Illumina tag 16S rRNA gene sequencing (iTag. Enrichment success and potential bias with iTag was evaluated in the context of full-length 16S rRNA gene clone libraries, CARD-FISH, functional gene clone libraries, and iTag mock communities. We determined commonly used Earth Microbiome Project (EMP iTAG primers introduced bias in some common methane seep microbial taxa that reduced the ability to directly compare OTU relative abundances within a sample, but comparison of relative abundances between samples (in nearly all cases and whole community-based analyses were robust. The iTag dataset was subjected to statistical co-occurrence measures of the most abundant OTUs to determine which taxa in this dataset were most correlated across all samples. Many non-canonical microbial partnerships were statistically significant in our co-occurrence network analysis, most of which were not recovered with conventional clone library sequencing, demonstrating the utility of combining Magneto-FISH and iTag sequencing methods for hypothesis generation of associations within complex microbial communities. Network analysis pointed to

  18. Characterization of microbial associations with methanotrophic archaea and sulfate-reducing bacteria through statistical comparison of nested Magneto-FISH enrichments.

    Science.gov (United States)

    Trembath-Reichert, Elizabeth; Case, David H; Orphan, Victoria J

    2016-01-01

    Methane seep systems along continental margins host diverse and dynamic microbial assemblages, sustained in large part through the microbially mediated process of sulfate-coupled Anaerobic Oxidation of Methane (AOM). This methanotrophic metabolism has been linked to consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). These two groups are the focus of numerous studies; however, less is known about the wide diversity of other seep associated microorganisms. We selected a hierarchical set of FISH probes targeting a range of Deltaproteobacteria diversity. Using the Magneto-FISH enrichment technique, we then magnetically captured CARD-FISH hybridized cells and their physically associated microorganisms from a methane seep sediment incubation. DNA from nested Magneto-FISH experiments was analyzed using Illumina tag 16S rRNA gene sequencing (iTag). Enrichment success and potential bias with iTag was evaluated in the context of full-length 16S rRNA gene clone libraries, CARD-FISH, functional gene clone libraries, and iTag mock communities. We determined commonly used Earth Microbiome Project (EMP) iTAG primers introduced bias in some common methane seep microbial taxa that reduced the ability to directly compare OTU relative abundances within a sample, but comparison of relative abundances between samples (in nearly all cases) and whole community-based analyses were robust. The iTag dataset was subjected to statistical co-occurrence measures of the most abundant OTUs to determine which taxa in this dataset were most correlated across all samples. Many non-canonical microbial partnerships were statistically significant in our co-occurrence network analysis, most of which were not recovered with conventional clone library sequencing, demonstrating the utility of combining Magneto-FISH and iTag sequencing methods for hypothesis generation of associations within complex microbial communities. Network analysis pointed to many co

  19. Inorganic phosphorus fertilizer ameliorates maize growth by reducing metal uptake, improving soil enzyme activity and microbial community structure.

    Science.gov (United States)

    Wu, Wencheng; Wu, Jiahui; Liu, Xiaowen; Chen, Xianbin; Wu, Yingxin; Yu, Shixiao

    2017-09-01

    Recently, several studies have showed that both organic and inorganic fertilizers are effective in immobilizing heavy metals at low cost, in comparison to other remediation strategies for heavy metal-contaminated farmlands. A pot trial was conducted in this study to examine the effects of inorganic P fertilizer and organic fertilizer, in single application or in combination, on growth of maize, heavy metal availabilities, enzyme activities, and microbial community structure in metal-contaminated soils from an electronic waste recycling region. Results showed that biomass of maize shoot and root from the inorganic P fertilizer treatments were respectively 17.8 and 10.0 folds higher than the un-amended treatments (CK), while the biomass in the organic fertilizer treatments was only comparable to the CK. In addition, there were decreases of 85.0% in Cd, 74.3% in Pb, 66.3% in Cu, and 91.9% in Zn concentrations in the roots of maize grown in inorganic P fertilizer amended soil. Consistently, urease and catalase activities in the inorganic P fertilizer amended soil were 3.3 and 2.0 times higher than the CK, whereas no enhancement was observed in the organic fertilizer amended soil. Moreover, microbial community structure was improved by the application of inorganic P fertilizer, but not by organic fertilizer; the beneficial microbial groups such as Kaistobacter and Koribacter were most frequently detected in the inorganic P fertilizer amended soil. The negligible effect from the organic fertilizer might be ascribed to the decreased pH value in soils. The results suggest that the application of inorganic P fertilizer (or in combination with organic fertilizer) might be a promising strategy for the remediation of heavy metals contaminated soils in electronic waste recycling region. Copyright © 2017. Published by Elsevier Inc.

  20. Application of molecular microbial ecology tools to facilitate the development of feeding systems for ruminant livestock that reduce greenhouse gas emissions

    International Nuclear Information System (INIS)

    McCrabb, G.J.; Fernandez-Rivera, S.; McSweeney, C.S.; Denman, S.; Mitsumori, M.; Makkar, H.P.S.

    2005-01-01

    Ruminant livestock populations in developing countries are increasing in response to increasing demand for meat and milk. These animals are a major global source of methane, a greenhouse gas produced during the degradation of organic matter by micro-organisms in the foregut of ruminant livestock. Chemical inhibition of methanogenic micro-organisms has been reported; however, associated improvements in feed digestion and livestock productivity have not been consistently demonstrated. Gene-based technologies have the potential to contribute new knowledge of the rumen microbial populations involved in these processes, which will assist in identifying feeding practices that lead to methane abatement and improved livestock productivity. For small-scale farmers, feeding interventions that achieve greenhouse gas abatement need also to be associated with improved feed conversion efficiency and enterprise profitability. During the adoption of methane abatement technologies, other regionally important issues such as poverty, food security, sustainable agriculture production systems and environmental management must also be addressed. (author)

  1. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt

    2008-11-01

    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

  2. Dose-response effects of dietary pequi oil on fermentation characteristics and microbial population using a rumen simulation technique (Rusitec).

    Science.gov (United States)

    Duarte, Andrea Camacho; Durmic, Zoey; Vercoe, Philip E; Chaves, Alexandre V

    2017-12-01

    The effect of increasing the concentration of commercial pequi (Caryocar brasiliense) oil on fermentation characteristics and abundance of methanogens and fibrolityc bacteria was evaluated using the rumen simulation technique (Rusitec). In vitro incubation was performed over 15 days using a basal diet consisting of ryegrass, maize silage and concentrate in equal proportions. Treatments consisted of control diet (no pequi oil inclusion, 0 g/kg DM), pequi dose 1 (45 g/kg DM), and pequi dose 2 (91 g/kg DM). After a 7 day adaptation period, samples for fermentation parameters (total gas, methane, and VFA production) were taken on a daily basis. Quantitative real time PCR (q-PCR) was used to evaluate the abundance of the main rumen cellulolytic bacteria, as well as abundance of methanogens. Supplementation with pequi oil did not reduce overall methane production (P = 0.97), however a tendency (P = 0.06) to decrease proportion of methane in overall microbial gas was observed. Increasing addition of pequi oil was associated with a linear decrease (P < 0.01) in dry matter disappearance of maize silage. The abundance of total methanogens was unchanged by the addition of pequi oil, but numbers of those belonging to Methanomassiliicoccaceae decreased in liquid-associated microbes (LAM) samples (P < 0.01) and solid-associated microbes (SAM) samples (P = 0.09) respectively, while Methanobrevibacter spp. increased (P < 0.01) only in SAM samples. Fibrobacter succinogenes decreased (P < 0.01) in both LAM and SAM samples when substrates were supplemented with pequi oil. In conclusion, pequi oil was ineffective in mitigating methane emissions and had some adverse effects on digestibility and selected fibrolytic bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Population-level interventions to reduce alcohol-related harm: an overview of systematic reviews.

    Science.gov (United States)

    Martineau, Fred; Tyner, Elizabeth; Lorenc, Theo; Petticrew, Mark; Lock, Karen

    2013-10-01

    To analyse available review-level evidence on the effectiveness of population-level interventions in non-clinical settings to reduce alcohol consumption or related health or social harm. Health, social policy and specialist review databases between 2002 and 2012 were searched for systematic reviews of the effectiveness of population-level alcohol interventions on consumption or alcohol-related health or social outcomes. Data were extracted on review research aim, inclusion criteria, outcome indicators, results, conclusions and limitations. Reviews were quality-assessed using AMSTAR criteria. A narrative synthesis was conducted overall and by policy area. Fifty-two reviews were included from ten policy areas. There is good evidence for policies and interventions to limit alcohol sale availability, to reduce drink-driving, to increase alcohol price or taxation. There is mixed evidence for family- and community-level interventions, school-based interventions, and interventions in the alcohol server setting and the mass media. There is weak evidence for workplace interventions and for interventions targeting illicit alcohol sales. There is evidence of the ineffectiveness of interventions in higher education settings. There is a pattern of support from the evidence base for regulatory or statutory enforcement interventions over local non-regulatory approaches targeting specific population groups. © 2013.

  4. Reducing Uncertainty in the Daycent Model of Heterotrophic Respiration with a More Mechanistic Representation of Microbial Processes.

    Science.gov (United States)

    Berardi, D.; Gomez-Casanovas, N.; Hudiburg, T. W.

    2017-12-01

    Improving the certainty of ecosystem models is essential to ensuring their legitimacy, value, and ability to inform management and policy decisions. With more than a century of research exploring the variables controlling soil respiration, a high level of uncertainty remains in the ability of ecosystem models to accurately estimate respiration with changing climatic conditions. Refining model estimates of soil carbon fluxes is a high priority for climate change scientists to determine whether soils will be carbon sources or sinks in the future. We found that DayCent underestimates heterotrophic respiration by several magnitudes for our temperate mixed conifer forest site. While traditional ecosystem models simulate decomposition through first order kinetics, recent research has found that including microbial mechanisms explains 20 percent more spatial heterogeneity. We manipulated the DayCent heterotrophic respiration model to include a more mechanistic representation of microbial dynamic and compared the new model with continuous and survey observations from our experimental forest site in the Northern Rockies ecoregion. We also calibrated the model's sensitivity to soil moisture and temperature to our experimental data. We expect to improve the accuracy of the model by 20-30 percent. By using a more representative and calibrated model of soil carbon dynamics, we can better predict feedbacks between climate and soil carbon pools.

  5. Reduced swimming performance repeatedly evolves upon loss of migration in landlocked populations of Alewife

    Science.gov (United States)

    Velotta, Jonathan P.; McCormick, Stephen; Jones, Andrew W.; Schultz, Eric T.

    2018-01-01

    Whole-organism performance tasks are accomplished by the integration of morphological traits and physiological functions. Understanding how evolutionary change in morphology and physiology influences whole-organism performance will yield insight into the factors that shape its own evolution. We demonstrate that nonmigratory populations of alewife (Alosa pseudoharengus) have evolved reduced swimming performance in parallel, compared with their migratory ancestor. In contrast to theoretically and empirically based predictions, poor swimming among nonmigratory populations is unrelated to the evolution of osmoregulation and occurs despite the fact that nonmigratory alewives have a more fusiform (torpedo-like) body shape than their ancestor. Our results suggest that elimination of long-distance migration from the life cycle has shaped performance more than changes in body shape and physiological regulatory capacity.

  6. Clinical Effects of Stabilized Stannous Fluoride Dentifrice in Reducing Plaque Microbial Virulence I: Microbiological and Receptor Cell Findings.

    Science.gov (United States)

    Klukowska, Malgorzata; Haught, John Christian; Xie, Sancai; Circello, Ben; Tansky, Cheryl S; Khambe, Deepa; Huggins, Tom; White, Donald J

    2017-06-01

    Lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs), or bacterial endotoxins, bind with Toll-like receptors (TLRs) that are expressed on host cells of the periodontium, thereby contributing to the periodontal pathogenicity of oral bacteria. Stannous fluoride (SnF2), an antibacterial fluoride that treats and controls gingivitis, has been shown to react with lipophilic domains/anionic charges in LPS and LTA. The effects of bacterial species and dental plaque on toll receptors can be studied using genetically engineered cell lines containing linked toll receptors on their surfaces. This randomized, examiner-blinded study examined the clinical effects of stabilized SnF2 dentifrice intervention on gingivitis and dental plaque virulence in populations exhibiting high and low levels of clinical gingivitis. Recruited populations were evaluated for gingival inflammation (MGI) and gingival bleeding (GBI) at baseline and assigned into two cohorts of 20 each, those with high (GBI > 20 sites) and low (GBI plaque at both healthy (no bleeding, PD = 2 mm), as well as clinically diseased sites (bleeding, PD = 3-4 mm), and then provided with an intervention hygiene product including a stabilized SnF2 dentifrice and a new soft bristle manual toothbrush. Following two and four weeks of assigned dentifrice use, participants returned for a re-evaluation of gingival inflammation and bleeding and repeat samplings of dental plaque. Plaque samples were analyzed by anaerobic culturing of gram negative anaerobes (GNA), as well as by incubation of subgingival sampled plaques with TLR4 transfected HEK293 cells, where gene expression was assessed by measurement of a SEAP alkaline phosphatase reporter as a marker of toll receptor activation. Clinical assessments showed statistically significant reductions in MGI (24-26%) and GBI (42-53%) gingivitis in both diseased and healthy cohorts following four weeks of dentifrice intervention. For all clinical examinations, MGI and bleeding sites were

  7. Numbers, biomass and cultivable diversity of microbial populations relate to depth and borehole-specific conditions in groundwater from depths of 4-450 m in Olkiluoto, Finland.

    Science.gov (United States)

    Pedersen, Karsten; Arlinger, Johanna; Eriksson, Sara; Hallbeck, Anna; Hallbeck, Lotta; Johansson, Jessica

    2008-07-01

    Microbiology, chemistry and dissolved gas in groundwater from Olkiluoto, Finland, were analysed over 3 years; samples came from 16 shallow observation tubes and boreholes from depths of 3.9-16.2 m and 14 deep boreholes from depths of 35-742 m. The average total number of cells (TNC) was 3.9 x 10(5) cells per ml in the shallow groundwater and 5.7 x 10(4) cells per ml in the deep groundwater. There was a significant correlation between the amount of biomass, analysed as ATP concentration, and TNC. ATP concentration also correlated with the stacked output of anaerobic most probable number cultivations of nitrate-, iron-, manganese- and sulphate-reducing bacteria, and acetogenic bacteria and methanogens. The numbers and biomass varied at most by approximately three orders of magnitude between boreholes, and TNC and ATP were positively related to the concentration of dissolved organic carbon. Two depth zones were found where the numbers, biomass and diversity of the microbial populations peaked. Shallow groundwater down to a depth of 16.2 m on average contained more biomass and cultivable microorganisms than did deep groundwater, except in a zone at a depth of approximately 300 m where the average biomass and number of cultivable microorganisms approached those of shallow groundwater. Starting at a depth of approximately 300 m, there were steep gradients of decreasing sulphate and increasing methane concentrations with depth; together with the peaks in biomass and sulphide concentration at this depth, these suggest that anaerobic methane oxidation may be a significant process at depth in Olkiluoto.

  8. Reduced satellite cell population may lead to contractures in children with cerebral palsy.

    Science.gov (United States)

    Smith, Lucas R; Chambers, Henry G; Lieber, Richard L

    2013-03-01

    Satellite cells are the stem cells residing in muscle responsible for skeletal muscle growth and repair. Skeletal muscle in cerebral palsy (CP) has impaired longitudinal growth that results in muscle contractures. We hypothesized that the satellite cell population would be reduced in contractured muscle. We compared the satellite cell populations in hamstring muscles from participants with CP contracture (n=8; six males, two females; age range 6-15y; Gross Motor Function Classification System [GMFCS] levels II-V; 4 with hemiplegia, 4 with diplegia) and from typically developing participants (n=8; six males, two females, age range 15-18y). Muscle biopsies were extracted from the gracilis and semitendinosus muscles and mononuclear cells were isolated. Cell surface markers were stained with fluorescently conjugated antibodies to label satellite cells (neural cell adhesion molecule) and inflammatory and endothelial cells (CD34 and CD4 respectively). Cells were analyzed using flow cytometry to determine cell populations. After gating for intact cells a mean of 12.8% (SD 2.8%) were determined to be satellite cells in typically developing children, but only 5.3% (SD 2.3%; p0.05) suggesting the isolation procedure was valid. A reduced satellite cell population may account for the decreased longitudinal growth of muscles in CP that develop into fixed contractures or the decreased ability to strengthen muscle in CP. This suggests a unique musculoskeletal disease mechanism and provides a potential therapeutic target for debilitating muscle contractures. © The Authors. Developmental Medicine & Child Neurology © 2012 Mac Keith Press.

  9. Impact of fermentation and addition of non-starch polysaccharide-degrading enzymes on microbial population and on digestibility of dried distillers grains with solubles in pigs

    DEFF Research Database (Denmark)

    Venås Jakobsen, Grethe; Jensen, Bent Borg; Knudsen, Knud Erik Bach

    2015-01-01

    Fluctuating prices on feedstock has led to a growing interest in alternative feed ingredients. Co-products from the biofuel industry are hence interesting to include in pig feeds, primarily due to the high protein content. Low nutritional value due to a high content of dietary fibre, however...... of cellulase and xylanase (CelXyl). Microbial population during fermentation of the treatments was determined and apparent ileal and total tract digestibility were measured on eight barrows surgically fitted with a simple T-shaped cannula at the distal ileum and fed the four treatments according to a double......-Latin square design. Microbial activity of the three fermented DDGS treatments was relatively low with lactic acid bacteria counts between 8.8 and 8.9 log cfu/g and lactic acid concentrations between 60.2 and 70.5 mmol/kg. The addition of CelXyl to DDGS resulted in a significant decrease in the amount of non...

  10. Diversity and Composition of Sulfate-Reducing Microbial Communities Based on Genomic DNA and RNA Transcription in Production Water of High Temperature and Corrosive Oil Reservoir

    Directory of Open Access Journals (Sweden)

    Xiao-Xiao Li

    2017-06-01

    Full Text Available Deep subsurface petroleum reservoir ecosystems harbor a high diversity of microorganisms, and microbial influenced corrosion is a major problem for the petroleum industry. Here, we used high-throughput sequencing to explore the microbial communities based on genomic 16S rDNA and metabolically active 16S rRNA analyses of production water samples with different extents of corrosion from a high-temperature oil reservoir. Results showed that Desulfotignum and Roseovarius were the most abundant genera in both genomic and active bacterial communities of all the samples. Both genomic and active archaeal communities were mainly composed of Archaeoglobus and Methanolobus. Within both bacteria and archaea, the active and genomic communities were compositionally distinct from one another across the different oil wells (bacteria p = 0.002; archaea p = 0.01. In addition, the sulfate-reducing microorganisms (SRMs were specifically assessed by Sanger sequencing of functional genes aprA and dsrA encoding the enzymes adenosine-5′-phosphosulfate reductase and dissimilatory sulfite reductase, respectively. Functional gene analysis indicated that potentially active Archaeoglobus, Desulfotignum, Desulfovibrio, and Thermodesulforhabdus were frequently detected, with Archaeoglobus as the most abundant and active sulfate-reducing group. Canonical correspondence analysis revealed that the SRM communities in petroleum reservoir system were closely related to pH of the production water and sulfate concentration. This study highlights the importance of distinguishing the metabolically active microorganisms from the genomic community and extends our knowledge on the active SRM communities in corrosive petroleum reservoirs.

  11. Diversity and Composition of Sulfate-Reducing Microbial Communities Based on Genomic DNA and RNA Transcription in Production Water of High Temperature and Corrosive Oil Reservoir

    Science.gov (United States)

    Li, Xiao-Xiao; Liu, Jin-Feng; Zhou, Lei; Mbadinga, Serge M.; Yang, Shi-Zhong; Gu, Ji-Dong; Mu, Bo-Zhong

    2017-01-01

    Deep subsurface petroleum reservoir ecosystems harbor a high diversity of microorganisms, and microbial influenced corrosion is a major problem for the petroleum industry. Here, we used high-throughput sequencing to explore the microbial communities based on genomic 16S rDNA and metabolically active 16S rRNA analyses of production water samples with different extents of corrosion from a high-temperature oil reservoir. Results showed that Desulfotignum and Roseovarius were the most abundant genera in both genomic and active bacterial communities of all the samples. Both genomic and active archaeal communities were mainly composed of Archaeoglobus and Methanolobus. Within both bacteria and archaea, the active and genomic communities were compositionally distinct from one another across the different oil wells (bacteria p = 0.002; archaea p = 0.01). In addition, the sulfate-reducing microorganisms (SRMs) were specifically assessed by Sanger sequencing of functional genes aprA and dsrA encoding the enzymes adenosine-5′-phosphosulfate reductase and dissimilatory sulfite reductase, respectively. Functional gene analysis indicated that potentially active Archaeoglobus, Desulfotignum, Desulfovibrio, and Thermodesulforhabdus were frequently detected, with Archaeoglobus as the most abundant and active sulfate-reducing group. Canonical correspondence analysis revealed that the SRM communities in petroleum reservoir system were closely related to pH of the production water and sulfate concentration. This study highlights the importance of distinguishing the metabolically active microorganisms from the genomic community and extends our knowledge on the active SRM communities in corrosive petroleum reservoirs. PMID:28638372

  12. Use of Fe-Impregnated Biochar To Efficiently Sorb Chlorpyrifos, Reduce Uptake by Allium fistulosum L., and Enhance Microbial Community Diversity.

    Science.gov (United States)

    Tang, Xiao-Yan; Huang, Wen-Da; Guo, Jing-Jing; Yang, Yang; Tao, Ran; Feng, Xu

    2017-07-05

    Fe-impregnated biochar was assessed as a method to remove the pesticide pollutant chlorpyrifos, utilizing biochar/FeO x composite synthesized via chemical coprecipitation of Fe 3+ /Fe 2+ onto Cyperus alternifolius biochar. Fe-impregnated biochar exhibited a higher sorption capacity than pristine biochar, resulting in more efficient removal of chlorpyrifos from water. Soil was dosed with pristine or Fe-impregnated biochar at 0.1 or 1.0% w/w, to evaluate chlorpyrifos uptake in Allium fistulosum L. (Welsh onion). The results showed that the average concentration of chlorpyrifos and its degradation product, 3,5,6-trichloro-2-pyridinol (TCP), decreased in A. fistulosum L. with increased levels of pristine biochar and Fe-biochar. Fe-biochar was found to be more effective in reducing the uptake of chlorpyrifos by improving the sorption ability and increasing plant root iron plaque. Bioavailability of chlorpyrifos is reduced with both biochar and Fe-biochar soil dosing; however, the greatest persistence of chlorpyrifos residues was observed with 1.0% pristine biochar. Microbial community analysis showed Fe-biochar to have a positive impact on the efficiency of chlorpyrifos degradation in soils, possibly by altering microbial communities.

  13. Simultaneous inhibition of sulfate-reducing bacteria, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl: Applications for microbial enhanced oil recovery.

    Science.gov (United States)

    Zhao, Feng; Zhou, Ji-Dong; Ma, Fang; Shi, Rong-Jiu; Han, Si-Qin; Zhang, Jie; Zhang, Ying

    2016-05-01

    Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Suspension of oysters reduces the populations of Vibrio parahaemolyticus and Vibrio vulnificus.

    Science.gov (United States)

    Cole, K M; Supan, J; Ramirez, A; Johnson, C N

    2015-09-01

    Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) are associated with the consumption of raw oysters and cause illnesses ranging from simple gastroenteritis to life-threatening septicaemia. These halophilic bacteria are frequently found in marine and estuarine systems, accumulating within the tissues of a number of aquatic organisms and passing on to humans after consumption, through contaminated water, or via open wounds. As benthic organisms capable of filtering 40 gallons of water per hour, sediment is an important source of potentially pathogenic vibrios in oysters destined for raw consumption. This research used off-bottom oyster culture to reduce vibrio concentrations in oysters. Colony hybridization was used to enumerate Vp and Vv in bottom and suspended oysters. Vv and Vp concentrations were generally lower in oysters suspended off-bottom, and suspension decreased vibrio loads in oysters by an average of 13%. Suspension of oysters reduced vibrio concentrations. This study found that oyster suspension significantly reduced some populations of potentially pathogenic vibrios. These results indicate that oyster suspension could be a viable approach for preharvest treatment to reduce illness in consumers of raw oysters. © 2015 The Society for Applied Microbiology.

  15. Plant growth promoting rhizobacteria reduce aphid population and enhance the productivity of bread wheat.

    Science.gov (United States)

    Naeem, Muhammad; Aslam, Zubair; Khaliq, Abdul; Ahmed, Jam Nazir; Nawaz, Ahmad; Hussain, Mubshar

    2018-04-24

    Plant growth promoting rhizobacteria increase plant growth and give protection against insect pests and pathogens. Due to the negative impact of chemical pesticides on environment, alternatives to these chemicals are needed. In this scenario, the biological methods of pest control offer an eco-friendly and an attractive option. In this study, the effect of two plant growth promoting rhizobacterial strains (Bacillus sp. strain 6 and Pseudomonas sp. strain 6K) on aphid population and wheat productivity was evaluated in an aphid susceptible (Pasban-90) and resistant (Inqlab-91) wheat cultivar. The seeds were inoculated with each PGPR strain, separately or the combination of both. The lowest aphid population (2.1tiller -1 ), and highest plant height (85.8cm), number of spikelets per spike (18), grains per spike (44), productive tillers (320m -2 ), straw yield (8.6Mgha -1 ), and grain yield (4.8Mgha -1 ) were achieved when seeds were inoculated with Bacillus sp. strain 6+Pseudomonas sp. strain 6K. The grain yield of both varieties was enhanced by 35.5-38.9% with seed inoculation with both bacterial strains. Thus, the combine use of both PGPR strains viz. Bacillus sp. strain 6+Pseudomonas sp. strain 6K offers an attractive option to reduce aphid population tied with better wheat productivity. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  16. Ability of Hand Hygiene Interventions Using Alcohol-Based Hand Sanitizers and Soap To Reduce Microbial Load on Farmworker Hands Soiled during Harvest.

    Science.gov (United States)

    de Aceituno, Anna Fabiszewski; Bartz, Faith E; Hodge, Domonique Watson; Shumaker, David J; Grubb, James E; Arbogast, James W; Dávila-Aviña, Jorgé; Venegas, Fabiola; Heredia, Norma; García, Santos; Leon, Juan S

    2015-11-01

    Effective hand hygiene is essential to prevent the spread of pathogens on produce farms and reduce foodborne illness. The U.S. Food and Drug Administration Food Safety Modernization Act Proposed Rule for Produce Safety recommends the use of soap and running water for hand hygiene of produce handlers. The use of alcohol-based hand sanitizer (ABHS) may be an effective alternative hygiene intervention where access to water is limited. There are no published data on the efficacy of either soap or ABHS-based interventions to reduce microbial contamination in agricultural settings. The goal of this study was to assess the ability of two soap-based (traditional or pumice) and two ABHS-based (label-use or two-step) hygiene interventions to reduce microbes (coliforms, Escherichia coli, and Enterococcus spp.) and soil (absorbance of hand rinsate at 600 nm [A600]) on farmworker hands after harvesting produce, compared with the results for a no-hand-hygiene control. With no hand hygiene, farmworker hands were soiled (median A600, 0.48) and had high concentrations of coliforms (geometric mean, 3.4 log CFU per hand) and Enterococcus spp. (geometric mean, 5.3 log CFU per hand) after 1 to 2 h of harvesting tomatoes. Differences in microbial loads in comparison to the loads in the control group varied by indicator organism and hygiene intervention (0 to 2.3 log CFU per hand). All interventions yielded lower concentrations of Enterococcus spp. and E. coli (P hands (P hand washing with soap at reducing indicator organisms on farmworker hands. Based on these results, ABHS is an efficacious hand hygiene solution for produce handlers, even on soiled hands.

  17. Dynamics of bacterial populations during bench-scale bioremediation of oily seawater and desert soil bioaugmented with coastal microbial mats.

    Science.gov (United States)

    Ali, Nidaa; Dashti, Narjes; Salamah, Samar; Sorkhoh, Naser; Al-Awadhi, Husain; Radwan, Samir

    2016-03-01

    This study describes a bench-scale attempt to bioremediate Kuwaiti, oily water and soil samples through bioaugmentation with coastal microbial mats rich in hydrocarbonoclastic bacterioflora. Seawater and desert soil samples were artificially polluted with 1% weathered oil, and bioaugmented with microbial mat suspensions. Oil removal and microbial community dynamics were monitored. In batch cultures, oil removal was more effective in soil than in seawater. Hydrocarbonoclastic bacteria associated with mat samples colonized soil more readily than seawater. The predominant oil degrading bacterium in seawater batches was the autochthonous seawater species Marinobacter hydrocarbonoclasticus. The main oil degraders in the inoculated soil samples, on the other hand, were a mixture of the autochthonous mat and desert soil bacteria; Xanthobacter tagetidis, Pseudomonas geniculata, Olivibacter ginsengisoli and others. More bacterial diversity prevailed in seawater during continuous than batch bioremediation. Out of seven hydrocarbonoclastic bacterial species isolated from those cultures, only one, Mycobacterium chlorophenolicum, was of mat origin. This result too confirms that most of the autochthonous mat bacteria failed to colonize seawater. Also culture-independent analysis of seawater from continuous cultures revealed high-bacterial diversity. Many of the bacteria belonged to the Alphaproteobacteria, Flavobacteria and Gammaproteobacteria, and were hydrocarbonoclastic. Optimal biostimulation practices for continuous culture bioremediation of seawater via mat bioaugmentation were adding the highest possible oil concentration as one lot in the beginning of bioremediation, addition of vitamins, and slowing down the seawater flow rate. © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  18. Reduced population size does not affect the mating strategy of a vulnerable and endemic seabird

    Science.gov (United States)

    Nava, Cristina; Neves, Verónica C.; Andris, Malvina; Dubois, Marie-Pierre; Jarne, Philippe; Bolton, Mark; Bried, Joël

    2017-12-01

    Bottleneck episodes may occur in small and isolated animal populations, which may result in decreased genetic diversity and increased inbreeding, but also in mating strategy adjustment. This was evaluated in the vulnerable and socially monogamous Monteiro's Storm-petrel Hydrobates monteiroi, a seabird endemic to the Azores archipelago which has suffered a dramatic population decline since the XVth century. To do this, we conducted a genetic study (18 microsatellite markers) in the population from Praia islet, which has been monitored over 16 years. We found no evidence that a genetic bottleneck was associated with this demographic decline. Monteiro's Storm-petrels paired randomly with respect to genetic relatedness and body measurements. Pair fecundity was unrelated to genetic relatedness between partners. We detected only two cases of extra-pair parentage associated with an extra-pair copulation (out of 71 offspring). Unsuccessful pairs were most likely to divorce the next year, but genetic relatedness between pair mates and pair breeding experience did not influence divorce. Divorce enabled individuals to improve their reproductive performances after re-mating only when the new partner was experienced. Re-pairing with an experienced partner occurred more frequently when divorcees changed nest than when they retained their nest. This study shows that even in strongly reduced populations, genetic diversity can be maintained, inbreeding does not necessarily occur, and random pairing is not risky in terms of pair lifetime reproductive success. Given, however, that we found no clear phenotypic mate choice criteria, the part played by non-morphological traits should be assessed more accurately in order to better understand seabird mating strategies.

  19. Improvement in shelf life of minimally processed cilantro leaves through integration of kinetin pretreatment and packaging interventions: Studies on microbial population dynamics, biochemical characteristics and flavour retention.

    Science.gov (United States)

    Ranjitha, K; Shivashankara, K S; Sudhakar Rao, D V; Oberoi, Harinder Singh; Roy, T K; Bharathamma, H

    2017-04-15

    Effect of integrating optimized combination of pretreatment with packaging on shelf life of minimally processed cilantro leaves (MPCL) was appraised through analysis of their sensory attributes, biochemical characteristics, microbial population and flavour profile during storage. Minimally pretreated cilantro leaves pretreated with 50ppm kinetin and packed in 25μ polypropylene bags showed a shelf life of 21days. Optimized combination helped in efficiently maintaining sensory parameters, flavour profile, and retention of antioxidants in MPCL until 21days. Studies conducted on the effect of optimized combination on microbial population and flavour profile revealed that among different microorganisms, pectinolysers had a significant effect on spoilage of MPCL and their population of ⩽3.59logcfu/g was found to be acceptable. Principal component analysis of headspace volatiles revealed that (E)-2-undecenal, (E)-2-hexadecenal, (E)-2-tetradecenal & (E)-2-tetradecen-1-ol in stored samples clustered with fresh samples and therefore, could be considered as freshness indicators for MPCL. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Mimicking microbial interactions under nitrate-reducing conditions in an anoxic bioreactor: enrichment of novel Nitrospirae bacteria distantly related to Thermodesulfovibrio.

    Science.gov (United States)

    Arshad, Arslan; Dalcin Martins, Paula; Frank, Jeroen; Jetten, Mike S M; Op den Camp, Huub J M; Welte, Cornelia U

    2017-12-01

    Microorganisms are main drivers of the sulfur, nitrogen and carbon biogeochemical cycles. These elemental cycles are interconnected by the activity of different guilds in sediments or wastewater treatment systems. Here, we investigated a nitrate-reducing microbial community in a laboratory-scale bioreactor model that closely mimicked estuary or brackish sediment conditions. The bioreactor simultaneously consumed sulfide, methane and ammonium at the expense of nitrate. Ammonium oxidation occurred solely by the activity of anammox bacteria identified as Candidatus Scalindua brodae and Ca. Kuenenia stuttgartiensis. Fifty-three percent of methane oxidation was catalyzed by archaea affiliated to Ca. Methanoperedens and 47% by Ca. Methylomirabilis bacteria. Sulfide oxidation was mainly shared between two proteobacterial groups. Interestingly, competition for nitrate did not lead to exclusion of one particular group. Metagenomic analysis showed that the most abundant taxonomic group was distantly related to Thermodesulfovibrio sp. (87-89% 16S rRNA gene identity, 52-54% average amino acid identity), representing a new family within the Nitrospirae phylum. A high quality draft genome of the new species was recovered, and analysis showed high metabolic versatility. Related microbial groups are found in diverse environments with sulfur, nitrogen and methane cycling, indicating that these novel Nitrospirae bacteria might contribute to biogeochemical cycling in natural habitats. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Myenteric denervation differentially reduces enteroendocrine serotonin cell population in rats during postnatal development.

    Science.gov (United States)

    Hernandes, Luzmarina; Fernandes, Marilda da Cruz; Pereira, Lucieni Cristina Marques da Silva; Freitas, Priscila de; Gama, Patrícia; Alvares, Eliana Parisi

    2006-05-01

    The enteric nervous and enteroendocrine systems regulate different processes in the small intestine. Ablation of myenteric plexus with benzalkonium chloride (BAC) stimulates epithelial cell proliferation, whereas endocrine serotonin cells may inhibit the process. To evaluate the connection between the systems and the influence of myenteric plexus on serotoninergic cells in rats during postnatal development, the ileal plexus was partially removed with BAC. Rats were treated at 13 or 21 days and sacrificed after 15 days. The cell bodies of myenteric neurons were stained by beta NADH-diaphorase to detect the extension of denervation. The number of enteroendocrine cells in the ileum was estimated in crypts and villi in paraffin sections immunostained for serotonin. The number of neurons was reduced by 27.6 and 45% in rats treated on the 13th and 21st days, respectively. We tried to establish a correlation of denervation and the serotonin population according to the age of treatment. We observed a reduction of immunolabelled cells in the crypts of rats treated at 13 days, whereas this effect was seen in the villi of rats denervated at 21 days. These results suggest that the enteric nervous system might control the enteroendocrine cell population and this complex mechanism could be correlated to changes in cell proliferation.

  2. Long-distance translocations to create a second millerbird population and reduce extinction risk

    Science.gov (United States)

    Holly Freifeld,; Sheldon Plentovich,; Chris Farmer,; Charles Kohley,; Peter Luscomb,; Work, Thierry M.; Daniel Tsukayama,; George Wallace,; Mark MacDonald,; Sheila Conant,

    2016-01-01

    Translocation is a conservation tool used with increasing frequency to create additional populations of threatened species. In addition to following established general guidelines for translocations, detailed planning to account for unique circumstances and intensive post-release monitoring to document outcomes and guide management are essential components of these projects. Recent translocation of the critically endangered Nihoa millerbird (Acrocephalus familiaris kingi) provides an example of this planning and monitoring. The Nihoa millerbird is a passerine bird endemic to Nihoa Island in the remote Northwestern Hawaiian Islands. The closely related, ecologically similar Laysan millerbird (Acrocephalus familiaris familiaris) went extinct on Laysan Island in the early 20th century when the island was denuded by introduced rabbits. To reduce extinction risk, we translocated 50 adult Nihoa millerbirds more than 1000 km by sea to Laysan, which has recovered substantially in the past century and has ample habitat and a rich prey-base for millerbirds. Following five years of intensive background research and planning, including development of husbandry techniques, fundraising, and regulatory compliance, translocations occurred in 2011 and 2012. Of 11 females in each cohort, 8 (2011 cohort) and 11 (2012 cohort) produced at least one brood of fledglings during their first year on Laysan. At the conclusion of monitoring in September 2014, 37 of the translocated birds were known to survive, and the population was estimated at 164 birds. The reintroduction of millerbirds to Laysan represents a milestone in the island's ongoing restoration.

  3. Professional and home-made face masks reduce exposure to respiratory infections among the general population.

    Science.gov (United States)

    van der Sande, Marianne; Teunis, Peter; Sabel, Rob

    2008-07-09

    Governments are preparing for a potential influenza pandemic. Therefore they need data to assess the possible impact of interventions. Face-masks worn by the general population could be an accessible and affordable intervention, if effective when worn under routine circumstances. We assessed transmission reduction potential provided by personal respirators, surgical masks and home-made masks when worn during a variety of activities by healthy volunteers and a simulated patient. All types of masks reduced aerosol exposure, relatively stable over time, unaffected by duration of wear or type of activity, but with a high degree of individual variation. Personal respirators were more efficient than surgical masks, which were more efficient than home-made masks. Regardless of mask type, children were less well protected. Outward protection (mask wearing by a mechanical head) was less effective than inward protection (mask wearing by healthy volunteers). Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission.

  4. Effects of Culture and 2-Hydroxy-4-(Methylthio-Butanoic Acid on Rumen Fermentation and Microbial Populations between Different Roughage Sources

    Directory of Open Access Journals (Sweden)

    H. Sun

    2014-09-01

    Full Text Available An in vitro experiment was conducted to evaluate the effects of Aspergillus oryzae culture (AOC and 2-hydroxy-4-(methylthio-butanoic acid (HMB on rumen fermentation and microbial populations between different roughage sources. Two roughage sources (Chinese wild rye [CWR] vs corn silage [CS] were assigned in a 2×3 factorial arrangement with HMB (0 or 15 mg and AOC (0, 3, or 6 mg. Gas production (GP, microbial protein (MCP and total volatile fatty acid (VFA were increased in response to addition of HMB and AOC (p<0.01 for the two roughages. The HMB and AOC showed inconsistent effects on ammonia-N with different substrates. For CWR, neither HMB nor AOC had significant effect on molar proportion of individual VFA. For CS, acetate was increased (p = 0.02 and butyrate was decreased (p<0.01 by adding HMB and AOC. Increase of propionate was only occurred with AOC (p<0.01. Populations of protozoa (p≤0.03 and fungi (p≤0.02 of CWR were differently influenced by HMB and AOC. Percentages of F. succinogenes, R. albus, and R. flavefaciens (p<0.01 increased when AOC was added to CWR. For CS, HMB decreased the protozoa population (p = 0.01 and increased the populations of F. succinogenes and R. albus (p≤0.03. Populations of fungi, F. succinogenes (p = 0.02 and R. flavefacien (p = 0.03 were increased by adding AOC. The HMB×AOC interactions were noted in MCP, fungi and R. flavefacien for CWR and GP, ammonia-N, MCP, total VFA, propionate, acetate/propionate (A/P and R. albus for CS. It is inferred that addition of HMB and AOC could influence rumen fermentation of forages by increasing the number of rumen microbes.

  5. Effects of Aspergillus Oryzae Culture and 2-Hydroxy-4-(Methylthio)-Butanoic Acid on In vitro Rumen Fermentation and Microbial Populations between Different Roughage Sources.

    Science.gov (United States)

    Sun, H; Wu, Y M; Wang, Y M; Liu, J X; Myung, K H

    2014-09-01

    An in vitro experiment was conducted to evaluate the effects of Aspergillus oryzae culture (AOC) and 2-hydroxy-4-(methylthio)-butanoic acid (HMB) on rumen fermentation and microbial populations between different roughage sources. Two roughage sources (Chinese wild rye [CWR] vs corn silage [CS]) were assigned in a 2×3 factorial arrangement with HMB (0 or 15 mg) and AOC (0, 3, or 6 mg). Gas production (GP), microbial protein (MCP) and total volatile fatty acid (VFA) were increased in response to addition of HMB and AOC (p<0.01) for the two roughages. The HMB and AOC showed inconsistent effects on ammonia-N with different substrates. For CWR, neither HMB nor AOC had significant effect on molar proportion of individual VFA. For CS, acetate was increased (p = 0.02) and butyrate was decreased (p<0.01) by adding HMB and AOC. Increase of propionate was only occurred with AOC (p<0.01). Populations of protozoa (p≤0.03) and fungi (p≤0.02) of CWR were differently influenced by HMB and AOC. Percentages of F. succinogenes, R. albus, and R. flavefaciens (p<0.01) increased when AOC was added to CWR. For CS, HMB decreased the protozoa population (p = 0.01) and increased the populations of F. succinogenes and R. albus (p≤0.03). Populations of fungi, F. succinogenes (p = 0.02) and R. flavefacien (p = 0.03) were increased by adding AOC. The HMB×AOC interactions were noted in MCP, fungi and R. flavefacien for CWR and GP, ammonia-N, MCP, total VFA, propionate, acetate/propionate (A/P) and R. albus for CS. It is inferred that addition of HMB and AOC could influence rumen fermentation of forages by increasing the number of rumen microbes.

  6. Examination of a Culturable Microbial Population from the Gastrointestinal Tract of the Wood-Eating Loricariid Catfish Panaque nigrolineatus

    Directory of Open Access Journals (Sweden)

    Harold J. Schreier

    2013-08-01

    Full Text Available Fish play a critical role in nutrient cycling and organic matter flow in aquatic environments. However, little is known about the microbial diversity within the gastrointestinal tracts that may be essential in these degradation activities. Panaque nigrolineatus is a loricariid catfish found in the Neotropics that have a rare dietary strategy of consuming large amounts of woody material in its natural environment. As a consequence, the gastrointestinal (GI tract of P. nigrolineatus is continually exposed to high levels of cellulose and other recalcitrant wood compounds and is, therefore, an attractive, uncharacterized system to study microbial community diversity. Our previous 16S rRNA gene surveys demonstrated that the GI tract microbial community includes phylotypes having the capacity to degrade cellulose and fix molecular nitrogen. In the present study we verify the presence of a resident microbial community by fluorescence microscopy and focus on the cellulose-degrading members by culture-based and 13C-labeled cellulose DNA stable-isotope probing (SIP approaches. Analysis of GI tract communities generated from anaerobic microcrystalline cellulose enrichment cultures by 16S rRNA gene analysis revealed phylotypes sharing high sequence similarity to known cellulolytic bacteria including Clostridium, Cellulomonas, Bacteroides, Eubacterium and Aeromonas spp. Related bacteria were identified in the SIP community, which also included nitrogen-fixing Azospirillum spp. Our ability to enrich for specialized cellulose-degrading communities suggests that the P. nigrolineatus GI tract provides a favorable environment for this activity and these communities may be involved in providing assimilable carbon under challenging dietary conditions.

  7. Yeast population dynamics reveal a potential 'collaboration' between Metschnikowia pulcherrima and Saccharomyces uvarum for the production of reduced alcohol wines during Shiraz fermentation.

    Science.gov (United States)

    Contreras, A; Curtin, C; Varela, C

    2015-02-01

    The wine sector is actively seeking strategies and technologies that facilitate the production of wines with lower alcohol content. One of the simplest approaches to achieve this aim would be the use of wine yeast strains which are less efficient at transforming grape sugars into ethanol; however, commercial wine yeasts have very similar ethanol yields. We recently demonstrated that Metschnikowia pulcherrima AWRI1149 was able to produce wine with reduced alcohol concentration when used in sequential inoculation with a wine strain of Saccharomyces cerevisiae. Here, different inoculation regimes were explored to study the effect of yeast population dynamics and potential yeast interactions on the metabolism of M. pulcherrima AWRI1149 during fermentation of non-sterile Shiraz must. Of all inoculation regimes tested, only ferments inoculated with M. pulcherrima AWRI1149 showed reduced ethanol concentration. Population dynamics revealed the presence of several indigenous yeast species and one of these, Saccharomyces uvarum (AWRI 2846), was able to produce wine with reduced ethanol concentration in sterile conditions. Both strains however, were inhibited when a combination of three non-Saccharomyces strains, Hanseniaspora uvarum AWRI863, Pichia kluyveri AWRI1896 and Torulaspora delbrueckii AWRI2845 were inoculated into must, indicating that the microbial community composition might impact on the growth of M. pulcherrima AWRI1149 and S. uvarum AWRI 2846. Our results indicate that mixed cultures of M. pulcherrima AWRI1149 and S. uvarum AWRI2846 enable an additional reduction of wine ethanol concentration compared to the same must fermented with either strain alone. This work thus provides a foundation to develop inoculation regimes for the successful application of non-cerevisiae yeast to the production of wines with reduced alcohol.

  8. Impacts of a national strategy to reduce population salt intake in England: serial cross sectional study.

    Science.gov (United States)

    Millett, Christopher; Laverty, Anthony A; Stylianou, Neophytos; Bibbins-Domingo, Kirsten; Pape, Utz J

    2012-01-01

    The UK introduced an ambitious national strategy to reduce population levels of salt intake in 2003. The aim of this study was to evaluate the impact of this strategy on salt intake in England, including potential effects on health inequalities. Secondary analysis of data from the Health Survey for England. Our main outcome measure was trends in estimated daily salt intake from 2003-2007, as measured by spot urine. Secondary outcome measures were knowledge of government guidance and voluntary use of salt in food preparation over this time period. There were significant reductions in salt intake between 2003 and 2007 (-0.175 grams per day per year, pprofessional; 64.9% v 71.0% AOR 0.76 95% CI 0.58-0.99). Self reported use of salt added at the table reduced significantly during the study period (56.5% to 40.2% pcooking (white 42.8%, black 74.1%, south Asian 88.3%) and those from lower social class groups (unskilled manual 46.6%, professional 35.2%) were more likely to add salt at the table. The introduction a national salt reduction strategy was associated with uniform but modest reductions in salt intake in England, although it is not clear precisely which aspects of the strategy contributed to this. Knowledge of government guidance was lower and voluntary salt use and total salt intake was higher among occupational and ethnic groups at greatest risk of cardiovascular disease.

  9. Effect of levels of urea and cassava chip on feed intake, rumen fermentation, blood metabolites and microbial populations in growing goats

    Directory of Open Access Journals (Sweden)

    Metha Wanapat

    2007-01-01

    Full Text Available The study was conducted to assess effect of levels of urea and cassava chip (CC on feed intake, rumen ecology, blood metabolites and microbial populations. Four, Thai Native X Anglo Nubian crossbred growing male goats with an average liveweight 19.0+1 kg were randomly assigned according to a 4x4 Latin square design to receive one of four diets: T1=urea at 0 % (CC=30%, T2=urea at 1% (CC=40%, T3=urea at 2% (CC = 50% and T4=urea at 3%(CC=60%, of DM basis, respectively. Elephant grass (Pennisetum purpureum was offered on an ad lib basis. The results revealed that total DM intake (%BW and g/kg W0.75 and BW change were similar among treatments (p>0.05. Likewise, rumen pH, BUN, blood glucose, PCV and microbial populations were similar among treatments (p>0.05, while NH3-N increased as the urea level increased and were found highest (p<0.05 in T4 at 12.8 mg/dL. Based on this experiment, it can be concluded that a higher level of urea (3% could be used with a high level of CC in concentrate and it was good approach in exploiting the use of local feed resources for goat production.

  10. Neonatal microbial colonization in mice promotes prolonged dominance of CD11b+Gr-1+cells and accelerated establishment of the CD4+T cell population in the spleen

    DEFF Research Database (Denmark)

    Kristensen, Matilde Bylov; Metzdorff, Stine Broeng; Bergström, Anders

    2015-01-01

    To assess the microbial influence on postnatal hematopoiesis, we examined the role of early life microbial colonization on the composition of leukocyte subsets in the neonatal spleen. A high number of CD11b+Gr-1+ splenocytes present perinatally was sustained for a longer period in conventionally...... event, which we suggest impacts the subsequent development of the T cell population in the murine spleen....

  11. Microbial ecology of a crude oil contaminated aquifer

    Science.gov (United States)

    Bekins, B.A.; Cozzarelli, I.M.; Warren, E.; Godsy, E.M.

    2002-01-01

    Detailed microbial analyses of a glacial outwash aquifer contaminated by crude oil provide insights into the pattern of microbial succession from iron reducing to methanogenic in the anaerobic portion of the contaminant plume. We analysed sediments from this area for populations of aerobes, iron reducers, fermenters and methanogens, using the most probable number method. On the basis of the microbial data the anaerobic area can be divided into distinct physiological zones dominated by either iron-reducers or a consortium of fermenters and methanogens. Chemistry and permeability data show that methanogenic conditions develop first in areas of high hydrocarbon flux. Thus, we find methanogens both in high permeability horizons and also where separate-phase crude oil is present in either the saturated or unsaturated zone. Microbial numbers peak at the top of the separate-phase oil suggesting that growth is most rapid in locations with access to both hydrocarbons and nutrients infiltrating from the surface.

  12. Microbial biotechnology and circular economy in wastewater treatment.

    Science.gov (United States)

    Nielsen, Per Halkjaer

    2017-09-01

    Microbial biotechnology is essential for the development of circular economy in wastewater treatment by integrating energy production and resource recovery into the production of clean water. A comprehensive knowledge about identity, physiology, ecology, and population dynamics of process-critical microorganisms will improve process stability, reduce CO2 footprints, optimize recovery and bioenergy production, and help finding new approaches and solutions. Examples of research needs and perspectives are provided, demonstrating the great importance of microbial biotechnology. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  13. Mind the gut : Genomic insights to population divergence and gut microbial composition of two marine keystone species

    NARCIS (Netherlands)

    Fietz, Katharina; Rye Hintze, Christian Olaf; Skovrind, Mikkel; Kjærgaard Nielsen, Tue; Limborg, Morten T; Krag, Marcus A; Palsbøll, Per J; Hestbjerg Hansen, Lars; Rask Møller, Peter; Gilbert, M Thomas P

    2018-01-01

    BACKGROUND: Deciphering the mechanisms governing population genetic divergence and local adaptation across heterogeneous environments is a central theme in marine ecology and conservation. While population divergence and ecological adaptive potential are classically viewed at the genetic level, it

  14. Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    of toluene, 2,4-DMP, 3,4-DMP and p-cresol depended on nitrate or nitrite as electron acceptors. 40–80% of the nitrate consumed during degradation of the aromatic compounds was recovered as nitrite, and the consumption of nitrate was accompanied by a production of ATP. Stoichiometric calculations indicated......Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture...... that in addition to the phenols are toluene other carbon sources present in the groundwater contributed to the consumption of nitrate. If the groundwater was incubated under anaerobic conditions without nitrate, sulphate-reducing conditions evolved after ∼ 1 month at 20°C and ∼2 months at 10°C. In the sulphate...

  15. The vaginal microbiome, vaginal anti-microbial defence mechanisms and the clinical challenge of reducing infection-related preterm birth.

    Science.gov (United States)

    Witkin, S S

    2015-01-01

    Ascending bacterial infection is implicated in about 40-50% of preterm births. The human vaginal microbiota in most women is dominated by lactobacilli. In women whose vaginal microbiota is not lactobacilli-dominated anti-bacterial defence mechanisms are reduced. The enhanced proliferation of pathogenic bacteria plus degradation of the cervical barrier increase bacterial passage into the endometrium and amniotic cavity and trigger preterm myometrial contractions. Evaluation of protocols to detect the absence of lactobaciili dominance in pregnant women by self-measuring vaginal pH, coupled with measures to promote growth of lactobacilli are novel prevention strategies that may reduce the occurrence of preterm birth in low-resource areas. © 2014 Royal College of Obstetricians and Gynaecologists.

  16. Using information technology to reduce asthma disparities in underserved populations: a pilot study.

    Science.gov (United States)

    Vargas, Perla A; Robles, Elias; Harris, Judith; Radford, Peggy

    2010-10-01

    Low health literacy has been identified as an independent predictor of poor asthma control. The Institute of Medicine considers the role of information technology (IT) as critical in providing "safe, effective, patient centered, timely, efficient, and equitable" care with the potential to reduce health disparities in underserved populations. The aim of this study was to design and evaluate an interactive computer-based questionnaire to assess asthma symptoms in children of parents with limited health literacy and/or limited English proficiency. Volunteer caregivers attending a mobile asthma clinic were randomly assigned to complete the electronic or the paper-and-pencil version of an asthma screening questionnaire (ASQ) in their language of choice (English or Spanish). In the electronic version, a tablet computer was used to present the ASQ questions as video clips and to collect information through the touchscreen. Participants also completed a demographic questionnaire, a brief health literacy questionnaire, and a system usability and satisfaction questionnaire. Reliability of the paper and electronic self-assessments was evaluated by comparing each participant's answers to information they provided during a nurse-guided structured interview (gold standard). A total of 48 parents participated in the study, 26 completed the electronic ASQ and 21 the paper-and-pencil form. Thirty-five percent of the children had well-controlled asthma (n = 17). Most participants were Spanish speaking (67%) Hispanic (n = 44) mothers (n = 43) with a median age of 32 years. More than half had ≤8 years of education (n = 25) and earned education was significant (ρ = .47, p higher than concordance between the paper ASQ and the nurse interview (68% versus 54%; p technology tools may help reduce barriers to access due to inadequate levels of English proficiency and health literacy.

  17. Impacts of a national strategy to reduce population salt intake in England: serial cross sectional study.

    Directory of Open Access Journals (Sweden)

    Christopher Millett

    Full Text Available BACKGROUND: The UK introduced an ambitious national strategy to reduce population levels of salt intake in 2003. The aim of this study was to evaluate the impact of this strategy on salt intake in England, including potential effects on health inequalities. METHODS: Secondary analysis of data from the Health Survey for England. Our main outcome measure was trends in estimated daily salt intake from 2003-2007, as measured by spot urine. Secondary outcome measures were knowledge of government guidance and voluntary use of salt in food preparation over this time period. RESULTS: There were significant reductions in salt intake between 2003 and 2007 (-0.175 grams per day per year, p<0.001. Intake decreased uniformly across all other groups but remained significantly higher in younger persons, men, ethnic minorities and lower social class groups and those without hypertension in 2007. Awareness of government guidance on salt use was lowest in those groups with the highest intake (semi-skilled manual v professional; 64.9% v 71.0% AOR 0.76 95% CI 0.58-0.99. Self reported use of salt added at the table reduced significantly during the study period (56.5% to 40.2% p<0.001. Respondents from ethnic minority groups remained significantly more likely to add salt during cooking (white 42.8%, black 74.1%, south Asian 88.3% and those from lower social class groups (unskilled manual 46.6%, professional 35.2% were more likely to add salt at the table. CONCLUSIONS: The introduction a national salt reduction strategy was associated with uniform but modest reductions in salt intake in England, although it is not clear precisely which aspects of the strategy contributed to this. Knowledge of government guidance was lower and voluntary salt use and total salt intake was higher among occupational and ethnic groups at greatest risk of cardiovascular disease.

  18. Association of prior HPV vaccination with reduced preterm birth: A population based study.

    Science.gov (United States)

    Lawton, Beverley; Howe, Anna S; Turner, Nikki; Filoche, Sara; Slatter, Tania; Devenish, Celia; Hung, Noelyn Anne

    2018-01-02

    Emerging evidence suggests that HPV infection is associated with negative pregnancy outcomes such as preterm birth (PTB), and pre-eclampsia. We aimed to determine if prior HPV vaccination reduced adverse pregnancy outcomes. A New Zealand population-based retrospective study linking first pregnancy outcome data (2008-2014 n = 35,646) with prior quadrivalent HPV vaccination status. Primary outcomes were likelihood (odds ratios, ORs) of PTB, pre-eclampsia, and stillbirth. Exposure groups were based on HPV vaccination. Adjusted ORs were calculated for each outcome, controlling for mother's age at delivery, ethnicity, socioeconomic status, health board region at time of delivery, and body mass index and smoking status at time of registration with maternity care provider. Mother's mean age at delivery was 19 (SD 2.1) years. Of 34,994 the pregnancies included in the final study analyses 62.3% of women were unvaccinated, 11.0% vaccinated with one or two doses and 27.7% vaccinated with three doses prior to pregnancy. PTB (OR: 0.87; CI 0.78, 0.96)) was significantly lower for women who previously received the HPV vaccine. A dose response effect was found with each successive dose received decreasing the likelihood of PTB. No associations between the vaccinated and unvaccinated groups were shown for pre-eclampsia or stillbirth. Prior receipt of the quadrivalent HPV vaccine was associated with a significant reduction in PTB (13%); suggesting that HPV vaccination may be effective in reducing PTB. The potential global public health impact is considerable and there is urgency to undertake further research to replicate and explore these findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    OpenAIRE

    Abdullah, Arman; Yahaya, Nordin; Md Noor, Norhazilan; Mohd Rasol, Rosilawati

    2014-01-01

    Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were i...

  20. Effect of nitrate, acetate and hydrogen on native perchlorate-reducing microbial communities and their activity in vadose soil

    Science.gov (United States)

    Nozawa-Inoue, Mamie; Jien, Mercy; Yang, Kun; Rolston, Dennis E.; Hristova, Krassimira R.; Scow, Kate M.

    2011-01-01

    Effect of nitrate, acetate and hydrogen on native perchlorate-reducing bacteria (PRB) was examined by conducting microcosm tests using vadose soil collected from a perchlorate-contaminated site. The rate of perchlorate reduction was enhanced by hydrogen amendment and inhibited by acetate amendment, compared to unamendment. Nitrate was reduced before perchlorate in all amendments. In hydrogen-amended and unamended soils, nitrate delayed perchlorate reduction, suggesting the PRB preferentially use nitrate as an electron acceptor. In contrast, nitrate eliminated the inhibitory effect of acetate amendment on perchlorate reduction and increased the rate and the extent, possibly because the preceding nitrate reduction/denitrification decreased the acetate concentration which was inhibitory to the native PRB. In hydrogen-amended and unamended soils, perchlorate reductase gene (pcrA) copies, representing PRB densities, increased with either perchlorate or nitrate reduction, suggesting either perchlorate or nitrate stimulates growth of the PRB. In contrast, in acetate-amended soil pcrA increased only when perchlorate was depleted: a large portion of the PRB may have not utilized nitrate in this amendment. Nitrate addition did not alter the distribution of the dominant pcrA clones in hydrogen-amended soil, likely because of the functional redundancy of PRB as nitrate-reducers/denitrifiers, whereas acetate selected different pcrA clones from those with hydrogen amendment. PMID:21284679

  1. Bioelectricity Production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells Using Indigenous Anode-Reducing Bacterial Community from Wastewater of Rice-Based Industries

    Directory of Open Access Journals (Sweden)

    Shailesh Kumar Jadhav

    2017-03-01

    Full Text Available Microbial fuel cells (MFCs are the electrochemical systems that harness the electricity production capacity of certain microbes from the reduction of biodegradable compounds. The present study aimed to develop mediator-less MFC without using expensive proton exchange membrane. In the present study, a triplicate of dual-chamber, mediator-less MFCs was operated with two local rice based industrial wastewater to explore the potential of this wastewater as a fuel option in these electrochemical systems. 30 combinations of 6 electrodes viz. Carbon (14 cm × 1.5 cm, Zn (14.9 cm × 4.9 cm, Cu (14.9 cm × 4.9 cm, Sn (14.1cm × 4.5cm, Fe (14cm × 4cm and Al (14cm × 4.5 cm were evaluated for each of the wastewater samples. Zn-C as anode-cathode combination produced a maximum voltage that was 1.084±0.016V and 1.086±0.028 and current of 1.777±0.115mA and 1.503±0.120 for KRM and SSR, respectively. In the present study, thick biofilm has been observed growing in MFC anode. Total 14 bacterial isolates growing in anode were obtained from two of the wastewater. The dual chambered, membrane-less and mediator-less MFCs were employed successfully to improve the economic feasibility of these electrochemical systems to generate bioelectricity and wastewater treatment simultaneously. Keywords: Membrane-less, Microbial Fuel Cells, Biofilm, Wastewater, Electrogenic. Article History: Received June 25th 2016; Received in revised form Dec 15th 2016; Accepted January 5th 2017; Available online How to Cite This Article: Reena, M. and Jadhav, S. K. (2017 Bioelectricity production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells using Indigenous Anode-reducing Bacterial Community from Wastewater of Rice-based Industries. International Journal of Renewable Energy Develeopment, 6(1, 83-92. http://dx.doi.org/10.14710/ijred.6.1.83-92

  2. Can Tobacco Control Be Transformative? Reducing Gender Inequity and Tobacco Use among Vulnerable Populations

    Science.gov (United States)

    Greaves, Lorraine

    2014-01-01

    Tobacco use and exposure is unequally distributed across populations and countries and among women and men. These trends and patterns reflect and cause gender and economic inequities along with negative health impacts. Despite a commitment to gender analysis in the preamble to Framework Convention on Tobacco Control there is much yet to be done to fully understand how gender operates in tobacco control. Policies, program and research in tobacco control need to not only integrate gender, but rather operationalize gender with the goal of transforming gender and social inequities in the course of tobacco control initiatives. Gender transformative tobacco control goes beyond gender sensitive efforts and challenges policy and program developers to apply gender theory in designing their initiatives, with the goal of changing negative gender and social norms and improving social, economic, health and social indicators along with tobacco reduction. This paper outlines what is needed to progress tobacco control in enhancing the status of gendered and vulnerable groups, with a view to reducing gender and social inequities due to tobacco use and exposure. PMID:24402065

  3. Smoking reduction and cessation reduce chronic cough in a general population: the Inter99 study

    DEFF Research Database (Denmark)

    Pisinger, Charlotta; Godtfredsen, Nina; Jørgensen, Torben

    2008-01-01

    % CI: 1.7-8.0), respectively, compared with unchanged smoking habits. It was also significantly more likely not to report phlegm at 1-year follow-up for those who had quit (OR: 7.1; 95% CI: 2.8-18.0), whereas SR was not significantly associated with termination of phlegm (OR: 2.5; 95% CI: 0.9-6.4) when......Background: Chronic cough can be the first sign of chronic obstructive disease. A few, and mostly selected, studies exploring the effect of reduced daily tobacco consumption have shown a small effect on pulmonary symptoms. Aim: The aim of this study was to examine if smoking reduction (SR) (>= 50......% of daily tobacco consumption) or smoking cessation (SC) had an effect on chronic cough and phlegm. Methods: A total of 2408 daily smokers were included in a Danish population-based intervention study, Inter99. In the analyses, we included smokers with self-reported chronic cough or phlegm at baseline who...

  4. Effect of feeding mode and dilution on the performance and microbial community population in anaerobic digestion of food waste.

    Science.gov (United States)

    Park, Jong-Hun; Kumar, Gopalakrishnan; Yun, Yeo-Myeong; Kwon, Joong-Chun; Kim, Sang-Hyoun

    2018-01-01

    The effect of feeding mode and dilution was studied in anaerobic digestion of food waste. An upflow anaerobic digester with a settler was fed at six different organic loading rates (OLRs) from 4.6 to 8.6kgCOD/m 3 /d for 200days. The highest methane productivity of 2.78LCH 4 /L/d was achieved at 8.6kgCOD/m 3 /d during continuous feeding of diluted FW. Continuous feeding of diluted food waste showed more stable and efficient performance than stepwise feeding of undiluted food waste. Sharp increase in propionate concentration attributed towards deterioration of the digester performances in stepwise feeding of undiluted food waste. Microbial communities at various OLRs divulged that the microbial distribution in the continuous feeding of diluted food waste was not significantly perturbed despite the increase of OLR up to 8.6kgCOD/m 3 /d, which was contrast to the unstable distribution in stepwise feeding of undiluted food waste at 6.1kgCOD/m 3 /d. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Microbial Database for Danish wastewater treatment plants with nutrient removal (MiDas-DK) - a tool for understanding activated sludge population dynamics and community stability.

    Science.gov (United States)

    Mielczarek, A T; Saunders, A M; Larsen, P; Albertsen, M; Stevenson, M; Nielsen, J L; Nielsen, P H

    2013-01-01

    Since 2006 more than 50 Danish full-scale wastewater treatment plants with nutrient removal have been investigated in a project called 'The Microbial Database for Danish Activated Sludge Wastewater Treatment Plants with Nutrient Removal (MiDas-DK)'. Comprehensive sets of samples have been collected, analyzed and associated with extensive operational data from the plants. The community composition was analyzed by quantitative fluorescence in situ hybridization (FISH) supported by 16S rRNA amplicon sequencing and deep metagenomics. MiDas-DK has been a powerful tool to study the complex activated sludge ecosystems, and, besides many scientific articles on fundamental issues on mixed communities encompassing nitrifiers, denitrifiers, bacteria involved in P-removal, hydrolysis, fermentation, and foaming, the project has provided results that can be used to optimize the operation of full-scale plants and carry out trouble-shooting. A core microbial community has been defined comprising the majority of microorganisms present in the plants. Time series have been established, providing an overview of temporal variations in the different plants. Interestingly, although most microorganisms were present in all plants, there seemed to be plant-specific factors that controlled the population composition thereby keeping it unique in each plant over time. Statistical analyses of FISH and operational data revealed some correlations, but less than expected. MiDas-DK (www.midasdk.dk) will continue over the next years and we hope the approach can inspire others to make similar projects in other parts of the world to get a more comprehensive understanding of microbial communities in wastewater engineering.

  6. Population-based biomedical sexually transmitted infection control interventions for reducing HIV infection.

    Science.gov (United States)

    Ng, Brian E; Butler, Lisa M; Horvath, Tara; Rutherford, George W

    2011-03-16

    The transmission of sexually transmitted infections (STIs) is closely related to the sexual transmission of human immunodeficiency virus (HIV). Similar risk behaviours, such as frequent unprotected intercourse with different partners, place people at high risk of HIV and STIs, and there is clear evidence that many STIs increase the likelihood of HIV transmission. STI control, especially at the population or community level, may have the potential to contribute substantially to HIV prevention.This is an update of an existing Cochrane review. The review's search methods were updated and its inclusion and exclusion criteria modified so that the focus would be on one well-defined outcome. This review now focuses explicitly on population-based biomedical interventions for STI control, with change in HIV incidence being an outcome necessary for a study's inclusion. To determine the impact of population-based biomedical STI interventions on the incidence of HIV infection. We searched PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science/Social Science, PsycINFO, and Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS), for the period of 1 January1980 - 16 August 2010. We initially identified 6003 articles and abstracts. After removing 776 duplicates, one author (TH) removed an additional 3268 citations that were clearly irrelevant. Rigorously applying the inclusion criteria, three authors then independently screened the remaining 1959 citations and abstracts. Forty-six articles were chosen for full-text scrutiny by two authors. Ultimately, four studies were included in the review.We also searched the Aegis database of conference abstracts, which includes the Conference on Retroviruses and Opportunistic Infections (CROI), the International AIDS Conference (IAC), and International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS) meetings from their inception dates (1993, 1985 and

  7. Microwave-Assisted Synthesis of Reduced Graphene Oxide/SnO2 Nanocomposite for Oxygen Reduction Reaction in Microbial Fuel Cells.

    Science.gov (United States)

    Garino, Nadia; Sacco, Adriano; Castellino, Micaela; Muñoz-Tabares, José Alejandro; Chiodoni, Angelica; Agostino, Valeria; Margaria, Valentina; Gerosa, Matteo; Massaglia, Giulia; Quaglio, Marzia

    2016-02-01

    We report on an easy, fast, eco-friendly, and reliable method for the synthesis of reduced graphene oxide/SnO2 nanocomposite as cathode material for application in microbial fuel cells (MFCs). The material was prepared starting from graphene oxide that has been reduced to graphene during the hydrothermal synthesis of the nanocomposite, carried out in a microwave system. Structural and morphological characterizations evidenced the formation of nanocomposite sheets, with SnO2 crystals of few nanometers integrated in the graphene matrix. Physico-chemical analysis revealed the formation of SnO2 nanoparticles, as well as the functionalization of the graphene by the presence of nitrogen atoms. Electrochemical characterizations put in evidence the ability of such composite to exploit a cocatalysis mechanism for the oxygen reduction reaction, provided by the presence of both SnO2 and nitrogen. In addition, the novel composite catalyst was successfully employed as cathode in seawater-based MFCs, giving electrical performances comparable to those of reference devices employing Pt as catalyst.

  8. Confirmation of putative stormwater impact on water quality at a Florida beach by microbial source tracking methods and structure of indicator organism populations.

    Science.gov (United States)

    Brownell, M J; Harwood, V J; Kurz, R C; McQuaig, S M; Lukasik, J; Scott, T M

    2007-08-01

    The effect of a stormwater conveyance system on indicator bacteria levels at a Florida beach was assessed using microbial source tracking methods, and by investigating indicator bacteria population structure in water and sediments. During a rain event, regulatory standards for both fecal coliforms and Enterococcus spp. were exceeded, contrasting with significantly lower levels under dry conditions. Indicator bacteria levels were high in sediments under all conditions. The involvement of human sewage in the contamination was investigated using polymerase chain reaction (PCR) assays for the esp gene of Enterococcus faecium and for the conserved T antigen of human polyomaviruses, all of which were negative. BOX-PCR subtyping of Escherichia coli and Enterococcus showed higher population diversity during the rain event; and higher population similarity during dry conditions, suggesting that without fresh inputs, only a subset of the population survives the selective pressure of the secondary habitat. These data indicate that high indicator bacteria levels were attributable to a stormwater system that acted as a reservoir and conduit, flushing high levels of indicator bacteria to the beach during a rain event. Such environmental reservoirs of indicator bacteria further complicate the already questionable relationship between indicator organisms and human pathogens, and call for a better understanding of the ecology, fate and persistence of indicator bacteria.

  9. Dietary Alfalfa and Calcium Salts of Long-Chain Fatty Acids Alter Protein Utilization, Microbial Populations, and Plasma Fatty Acid Profile in Holstein Freemartin Heifers.

    Science.gov (United States)

    He, Yang; Qiu, Qinghua; Shao, Taoqi; Niu, Wenjing; Xia, Chuanqi; Wang, Haibo; Li, Qianwen; Gao, Zhibiao; Yu, Zhantao; Su, Huawei; Cao, Binghai

    2017-12-20

    This study presented the effects of alfalfa and calcium salts of long-chain fatty acids (CSFA) on feed intake, apparent digestibility, rumen fermentation, microbial community, plasma biochemical parameters, and fatty acid profile in Holstein freemartin heifers. Eight Holstein freemartin heifers were randomly divided into a 4 × 4 Latin Square experiment with 2 × 2 factorial diets, with or without alfalfa or CSFA. Dietary supplementation of CSFA significantly increased the apparent digestibility of dry matter, crude protein, neutral detergent fiber, organic matter, and significantly reduced N retention (P fatty acids in the plasma, which was expressed in reducing saturated fatty acid (ΣSFA) ratio and C14-C17 fatty acids proportion except C16:0 (P fatty acid (ΣPUFA) and unsaturated fatty acid (ΣUFA) (P fatty acids in plasma. Alfalfa and CSFA had mutual interaction effect on fat digestion and plasma triglycerides.

  10. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

    Science.gov (United States)

    Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

    2012-03-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. © 2011 Blackwell Publishing Ltd.

  11. Effects of various weaning times on growth performance, rumen fermentation and microbial population of yellow cattle calves

    Directory of Open Access Journals (Sweden)

    Huiling Mao

    2017-11-01

    Full Text Available Objective This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3 or to early weaned (EW group where calves were weaned when the feed intake of solid feed (starter reached 500 g (EW500, n = 5, 750 g (EW750, n = 5, or 1,000 g (EW1,000, n = 5. Results Compared with NW, the EW treatments increased average daily gain (p0.05, but changes in bacterial composition were found. Conclusion From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results.

  12. Virulence-associated and antibiotic resistance genes of microbial populations in cattle feces analyzed using a metagenomic approach.

    Science.gov (United States)

    Durso, Lisa M; Harhay, Gregory P; Bono, James L; Smith, Timothy P L

    2011-02-01

    The bovine fecal microbiota impacts human food safety as well as animal health. Although the bacteria of cattle feces have been well characterized using culture-based and culture-independent methods, techniques have been lacking to correlate total community composition with community function. We used high throughput sequencing of total DNA extracted from fecal material to characterize general community composition and examine the repertoire of microbial genes present in beef cattle feces, including genes associated with antibiotic resistance and bacterial virulence. Results suggest that traditional 16S sequencing using "universal" primers to generate full-length sequence may under represent Acitinobacteria and Proteobacteria. Over eight percent (8.4%) of the sequences from our beef cattle fecal pool sample could be categorized as virulence genes, including a suite of genes associated with resistance to antibiotic and toxic compounds (RATC). This is a higher proportion of virulence genes found in Sargasso sea, chicken cecum, and cow rumen samples, but comparable to the proportion found in Antarctic marine derived lake, human fecal, and farm soil samples. The quantitative nature of metagenomic data, combined with the large number of RATC classes represented in samples from widely different habitats indicates that metagenomic data can be used to track relative amounts of antibiotic resistance genes in individual animals over time. Consequently, these data can be used to generate sample-specific and temporal antibiotic resistance gene profiles to facilitate an understanding of the ecology of the microbial communities in each habitat as well as the epidemiology of antibiotic resistant gene transport between and among habitats. Published by Elsevier B.V.

  13. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arman Abdullah

    2014-01-01

    Full Text Available Various cases of accidents involving microbiology influenced corrosion (MIC were reported by the oil and gas industry. Sulfate reducing bacteria (SRB have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP, and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

  14. The effect of sourdough and calcium propionate on the microbial shelf-life of salt reduced bread.

    Science.gov (United States)

    Belz, Markus C E; Mairinger, Regina; Zannini, Emanuele; Ryan, Liam A M; Cashman, Kevin D; Arendt, Elke K

    2012-10-01

    The consumption of low-salt bread represents an efficient way to improve public health by decreasing cardiovascular health issues related to increased intakes of sodium chloride (NaCl). The reduction of NaCl influences the bread quality characteristics, in particular the shelf-life. Calcium propionate (CP) is commonly used in bread as an antifungal agent. Alternatively, sourdough can be used as a natural preservative. This work addresses the feasibility of NaCl reduction in wheat bread focussing on shelf-life and the compensation using sourdough as well as chemical preservatives. The impact of NaCl reduction and the addition of preservative agents in conjunction with different NaCl concentrations on the shelf-life of bread were tested under 'environmental' conditions in a bakery as well as using challenge tests against selected fungi. The challenge tests were performed using fungi commonly found in the bakery environment such as Penicillium expansum, Fusarium culmorum and Aspergillus niger. NaCl reduction decreased the shelf-life by 1-2 days. The addition of sourdough with antifungal activity prolonged the shelf-life to 12-14 days whereas the addition of 0.3 % calcium propionate prolonged the shelf-life to 10-12 days only. The fungal challenge tests revealed differences in the determined shelf-life between the different fungi based on their resistance. Similar antifungal performance was observed in sourdough breads and calcium propionate breads when tested against the different indicator moulds. The findings of this study indicate that addition of sourdough fermented using a specifically selected antifungal Lactobacillus amylovorus DSM 19280 can replace the chemical preservative calcium propionate addition and compensate for the reduced level and, therefore, guarantee the product safety of low-salt bread.

  15. Evolutionary conservation advice for despotic populations: habitat heterogeneity favours conflict and reduces productivity in Seychelles magpie robins.

    Science.gov (United States)

    López-Sepulcre, Andrés; Kokko, Hanna; Norris, Ken

    2010-11-22

    Individual preferences for good habitat are often thought to have a beneficial stabilizing effect for populations. However, if individuals preferentially compete for better-quality territories, these may become hotspots of conflict. We show that, in an endangered species, this process decreases the productivity of favoured territories to the extent that differences in productivity between territories disappear. Unlike predictions from current demographic theory on site-dependent population regulation (ideal despotic distribution), we show that population productivity is reduced if resources are distributed unevenly in space. Competition for high-quality habitat can thus have detrimental consequences for populations even though it benefits individuals. Manipulating conflict (e.g. by reducing variation in habitat quality) can therefore prove an effective conservation measure in species with strong social or territorial conflict.

  16. Effect of temperature increase from 55 to 65 degrees C on performance and microbial population dynamics of an anaerobic reactor treating cattle manure

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Ibrahim, Ashraf; Mladenovska, Zuzana

    2001-01-01

    C, a decreased activity was found For glucosc-, acetate- , butyrate- and formate-utilizers and no significant activity was measured with propionate. Only the hydrogen-consuming methanogens showed an enhanced activity at 65 degreesC. Numbers of cultivable methanogens, estimated by the most probable number (MPN......The effect of a temperature increase from 55 to 65 degreesC on process performance and microbial population dynamics were investigated in thermophilic, lab-scale, continuously stirred tank reactors. The reactors had a working volume of 3 l and were fed with cattle manure at an organic loading rate....../d at 55 degreesC. Simultaneously, Ibe level of total volatile fatty acids, VFA, increased from being below 0.3g/l to 1.8-2.4g acetate/l. The specific methanogenic activities (SMA) of biomass from the reactors were measured with acetate, propionate, butyrate, hydrogen, formate and glucose. At 65 degrees...

  17. Does early indoor microbial exposure reduce the risk of asthma? The Prevention and Incidence of Asthma and Mite Allergy birth cohort study

    NARCIS (Netherlands)

    Douwes, J; van Strien, R; Doekes, G; Smit, Jet; Kerkhof, M; Gerritsen, J; Postma, D; Travier, N; Brunekreef, B

    Background: Exposure to microbial agents might inhibit the development of atopy and asthma. Objective: We measured the association between microbial exposure assessed at 3 months and the development of atopic sensitization and doctor-diagnosed (DD) asthma and wheeze in the first 4 years in a birth

  18. Microbial Populations in Naked Neck Chicken Ceca Raised on Pasture Flock Fed with Commercial Yeast Cell Wall Prebiotics via an Illumina MiSeq Platform.

    Directory of Open Access Journals (Sweden)

    Si Hong Park

    Full Text Available Prebiotics are non-digestible carbohydrate dietary supplements that selectively stimulate the growth of one or more beneficial bacteria in the gastrointestinal tract of the host. These bacteria can inhibit colonization of pathogenic bacteria by producing antimicrobial substances such as short chain fatty acids (SCFAs and competing for niches with pathogens within the gut. Pasture flock chickens are generally raised outdoors with fresh grass, sunlight and air, which represents different environmental growth conditions compared to conventionally raised chickens. The purpose of this study was to evaluate the difference in microbial populations from naked neck chicken ceca fed with commercial prebiotics derived from brewer's yeast cell wall via an Illumina MiSeq platform. A total of 147 day-of-hatch naked neck chickens were distributed into 3 groups consisted of 1 C: control (no prebiotic, 2 T1: Biolex® MB40 with 0.2%, and 3 T2: Leiber® ExCel with 0.2%, consistently supplemented prebiotics during the experimental period. At 8 weeks, a total of 15 birds from each group were randomly selected and ceca removed for DNA extraction. The Illumina Miseq platform based on V4 region of 16S rRNA gene was applied for microbiome analysis. Both treatments exhibited limited impact on the microbial populations at the phylum level, with no significant differences in the OTU number of Bacteroidetes among groups and an increase of Proteobacteria OTUs for the T1 (Biolex® MB40 group. In addition there was a significant increase of genus Faecalibacterium OTU, phylum Firmicutes. According to the development of next generation sequencing (NGS, microbiome analysis based on 16S rRNA gene proved to be informative on the prebiotic impact on poultry gut microbiota in pasture-raised naked neck birds.

  19. Microbial Populations in Naked Neck Chicken Ceca Raised on Pasture Flock Fed with Commercial Yeast Cell Wall Prebiotics via an Illumina MiSeq Platform.

    Science.gov (United States)

    Park, Si Hong; Lee, Sang In; Ricke, Steven C

    2016-01-01

    Prebiotics are non-digestible carbohydrate dietary supplements that selectively stimulate the growth of one or more beneficial bacteria in the gastrointestinal tract of the host. These bacteria can inhibit colonization of pathogenic bacteria by producing antimicrobial substances such as short chain fatty acids (SCFAs) and competing for niches with pathogens within the gut. Pasture flock chickens are generally raised outdoors with fresh grass, sunlight and air, which represents different environmental growth conditions compared to conventionally raised chickens. The purpose of this study was to evaluate the difference in microbial populations from naked neck chicken ceca fed with commercial prebiotics derived from brewer's yeast cell wall via an Illumina MiSeq platform. A total of 147 day-of-hatch naked neck chickens were distributed into 3 groups consisted of 1) C: control (no prebiotic), 2) T1: Biolex® MB40 with 0.2%, and 3) T2: Leiber® ExCel with 0.2%, consistently supplemented prebiotics during the experimental period. At 8 weeks, a total of 15 birds from each group were randomly selected and ceca removed for DNA extraction. The Illumina Miseq platform based on V4 region of 16S rRNA gene was applied for microbiome analysis. Both treatments exhibited limited impact on the microbial populations at the phylum level, with no significant differences in the OTU number of Bacteroidetes among groups and an increase of Proteobacteria OTUs for the T1 (Biolex® MB40) group. In addition there was a significant increase of genus Faecalibacterium OTU, phylum Firmicutes. According to the development of next generation sequencing (NGS), microbiome analysis based on 16S rRNA gene proved to be informative on the prebiotic impact on poultry gut microbiota in pasture-raised naked neck birds.

  20. Clinical epidemiology of reduced kidney function among elderly male fishing and agricultural population in Taipei, Taiwan.

    Science.gov (United States)

    Kuo, Chi-Mei; Chien, Wu-Hsiung; Shen, Hsi-Che; Hu, Yi-Chun; Chen, Yu-Fen; Tung, Tao-Hsin

    2013-01-01

    To quantify the prevalence of and associated factors for chronic kidney disease (CKD) among male elderly fishing and agricultural population in Taipei, Taiwan. Subjects (n = 2,766) aged 65 years and over voluntarily admitted to a teaching hospital for a physical checkup were collected in 2010. CKD was defined as an estimated glomerular filtration rate agricultural population.

  1. A short overview of the microbial population in clouds: Potential roles in atmospheric chemistry and nucleation processes

    Science.gov (United States)

    Delort, Anne-Marie; Vaïtilingom, Mickael; Amato, Pierre; Sancelme, Martine; Parazols, Marius; Mailhot, Gilles; Laj, Paolo; Deguillaume, Laurent

    2010-11-01

    Recent studies showed that living microorganisms, including bacteria, fungi and yeasts, are present in the atmospheric water phase (fog and clouds) and their role in chemical processes may have been underestimated. At the interface between atmospheric science and microbiology, information about this field of science suffers from the fact that not all recent findings are efficiently conveyed to both scientific communities. The purpose of this paper is therefore to provide a short overview of recent work linked to living organisms in the atmospheric water phase, from their activation to cloud droplets and ice crystal, to their potential impact on atmospheric chemical processes. This paper is focused on the microorganisms present in clouds and on the role they could play in atmospheric chemistry and nucleation processes. First, the life cycle of microorganisms via the atmosphere is examined, including their aerosolization from sources, their integration into clouds and their wet deposition on the ground. Second, special attention is paid to the possible impacts of microorganisms on liquid and ice nucleation processes. Third, a short description of the microorganisms that have been found in clouds and their variability in numbers and diversity is presented, emphasizing some specific characteristics that could favour their occurrence in cloud droplets. In the last section, the potential role of microbial activity as an alternative route to photochemical reaction pathways in cloud chemistry is discussed.

  2. Effects of Secondary Plant Metabolites on Microbial Populations: Changes in Community Structure and Metabolic Activity in Contaminated Environments

    Directory of Open Access Journals (Sweden)

    Lucie Musilova

    2016-07-01

    Full Text Available Secondary plant metabolites (SPMEs play an important role in plant survival in the environment and serve to establish ecological relationships between plants and other organisms. Communication between plants and microorganisms via SPMEs contained in root exudates or derived from litter decomposition is an example of this phenomenon. In this review, the general aspects of rhizodeposition together with the significance of terpenes and phenolic compounds are discussed in detail. We focus specifically on the effect of SPMEs on microbial community structure and metabolic activity in environments contaminated by polychlorinated biphenyls (PCBs and polyaromatic hydrocarbons (PAHs. Furthermore, a section is devoted to a complex effect of plants and/or their metabolites contained in litter on bioremediation of contaminated sites. New insights are introduced from a study evaluating the effects of SPMEs derived during decomposition of grapefruit peel, lemon peel, and pears on bacterial communities and their ability to degrade PCBs in a long-term contaminated soil. The presented review supports the “secondary compound hypothesis” and demonstrates the potential of SPMEs for increasing the effectiveness of bioremediation processes.

  3. Faecal Microbiota of Forage-Fed Horses in New Zealand and the Population Dynamics of Microbial Communities following Dietary Change

    Science.gov (United States)

    Fernandes, Karlette A.; Kittelmann, Sandra; Rogers, Christopher W.; Gee, Erica K.; Bolwell, Charlotte F.; Bermingham, Emma N.; Thomas, David G.

    2014-01-01

    The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet (“Group A”; n = 6) or pasture (“Group B”; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson’s index of diversity >0.8), with differences between the two groups on Day 0 (Phorses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa) of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change. PMID:25383707

  4. Effects of various weaning times on growth performance, rumen fermentation and microbial population of yellow cattle calves

    Science.gov (United States)

    Mao, Huiling; Xia, Yuefeng; Tu, Yan; Wang, Chong; Diao, Qiyu

    2017-01-01

    Objective This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3) or to early weaned (EW) group where calves were weaned when the feed intake of solid feed (starter) reached 500 g (EW500, n = 5), 750 g (EW750, n = 5), or 1,000 g (EW1,000, n = 5). Results Compared with NW, the EW treatments increased average daily gain (pcalves in EW750 had a higher (pintake than those in EW1,000 from wk 9 to the end of the trial. The concentrations of total volatile fatty acids in EW750 were greater than in NW and EW1,000 (p0.05), but changes in bacterial composition were found. Conclusion From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results. PMID:28423879

  5. Quantitative comparisons of select cultured and uncultured microbial populations in the rumen of cattle fed different diets

    Directory of Open Access Journals (Sweden)

    Kim Minseok

    2012-09-01

    Full Text Available Abstract Background The number and diversity of uncultured ruminal bacterial and archaeal species revealed by 16S rRNA gene (rrs sequences greatly exceeds that of cultured bacteria and archaea. However, the significance of uncultured microbes remains undetermined. The objective of this study was to assess the numeric importance of select uncultured bacteria and cultured bacteria and the impact of diets and microenvironments within cow rumen in a comparative manner. Results Liquid and adherent fractions were obtained from the rumen of Jersey cattle fed hay alone and Holstein cattle fed hay plus grain. The populations of cultured and uncultured bacteria present in each fraction were quantified using specific real-time PCR assays. The population of total bacteria was similar between fractions or diets, while total archaea was numerically higher in the hay-fed Jersey cattle than in the hay-grain-fed Holstein cattle. The population of the genus Prevotella was about one log smaller than that of total bacteria. The populations of Fibrobacter succinogenes, Ruminococcus flavefaciens, the genus Butyrivibrio, and R. albus was at least one log smaller than that of genus Prevotella. Four of the six uncultured bacteria quantified were as abundant as F. succinogenes, R. flavefaciens and the genus Butyrivibrio. In addition, the populations of several uncultured bacteria were significantly higher in the adherent fractions than in the liquid fractions. These uncultured bacteria may be associated with fiber degradation. Conclusions Some uncultured bacteria are as abundant as those of major cultured bacteria in the rumen. Uncultured bacteria may have important contribution to ruminal fermentation. Population dynamic studies of uncultured bacteria in a comparative manner can help reveal their ecological features and importance to rumen functions.

  6. Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution.

    Science.gov (United States)

    Altermatt, Florian; Ebert, Dieter

    2016-04-01

    The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of 'city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks. © 2016 The Author(s).

  7. Dietary pattern derived by reduced rank regression and depressive symptoms in a multi-ethnic population: the HELIUS study

    NARCIS (Netherlands)

    Vermeulen, E.; Stronks, K.; Visser, M.; Brouwer, I. A.; Snijder, M. B.; Mocking, R. J. T.; Derks, E. M.; Schene, A. H.; Nicolaou, M.

    2017-01-01

    BACKGROUND/OBJECTIVES: To investigate the association of dietary patterns derived by reduced rank regression (RRR) with depressive symptoms in a multi-ethnic population. SUBJECTS/METHODS: Cross-sectional data from the HELIUS study were used. In total, 4967 men and women (18-70 years) of Dutch,

  8. Dietary pattern derived by reduced rank regression and depressive symptoms in a multi-ethnic population: the HELIUS study

    NARCIS (Netherlands)

    Vermeulen, E.; Stronks, K.; Visser, M.; Brouwer, I. A.; Snijder, M. B.; Mocking, R. J.T.; Derks, E. M.; Schene, A. H.; Nicolaou, M.

    BACKGROUND/OBJECTIVES: To investigate the association of dietary patterns derived by reduced rank regression (RRR) with depressive symptoms in a multi-ethnic population. SUBJECTS/METHODS: Cross-sectional data from the HELIUS study were used. In total, 4967 men and women (18-70 years) of Dutch,

  9. Faecal microbiota of forage-fed horses in New Zealand and the population dynamics of microbial communities following dietary change.

    Science.gov (United States)

    Fernandes, Karlette A; Kittelmann, Sandra; Rogers, Christopher W; Gee, Erica K; Bolwell, Charlotte F; Bermingham, Emma N; Thomas, David G

    2014-01-01

    The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet ("Group A"; n = 6) or pasture ("Group B"; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson's index of diversity > 0.8), with differences between the two groups on Day 0 (P 003), CF231 (family Paraprevotellaceae; P = 0.004), and currently unclassified members within the order Clostridiales (P = 0.003) and within the family Lachnospiraceae (P = 0.006). The bacterial community of Group A horses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa) of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change.

  10. Faecal microbiota of forage-fed horses in New Zealand and the population dynamics of microbial communities following dietary change.

    Directory of Open Access Journals (Sweden)

    Karlette A Fernandes

    Full Text Available The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet ("Group A"; n = 6 or pasture ("Group B"; n = 6 for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson's index of diversity > 0.8, with differences between the two groups on Day 0 (P < 0.017 adjusted for multiple comparisons. There were differences between Groups A and B in the relative abundances of four genera, BF311 (family Bacteroidaceae; P = 0.003, CF231 (family Paraprevotellaceae; P = 0.004, and currently unclassified members within the order Clostridiales (P = 0.003 and within the family Lachnospiraceae (P = 0.006. The bacterial community of Group A horses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change.

  11. Grazing by sheep Ovis aries reduces island populations of water voles Arvicola amphibius

    Directory of Open Access Journals (Sweden)

    Karl Frafjord

    2014-12-01

    Full Text Available The population of water voles Arvicola amphibius was surveyed on 21 islands in the Solvær archipelago, northern Norway, in August 2012; 11 islands with semi-wild domestic sheep Ovis aries and 10 islands without sheep. Signs from water voles are very easy to detect and were used as a measure of the population (on a scale 0-10, and the numbers of sheep were counted. The ranking of signs on islands with and without sheep was compared, and a significant difference was found. Islands with sheep had, with one exception, only very small and fragmented populations of water voles, the one exception being a fairly large Carex swamp that was not grazed by the sheep and where a moderate-sized population of voles was found. Islands without sheep had much larger populations of water voles, giving a ranking about four times higher. One reason for the devastating effect of sheep on water voles is probably the fact that the sheep are living year-round on these islands with no supplemental food.

  12. Occurrence of the mcr-1 Colistin Resistance Gene and other Clinically Relevant Antibiotic Resistance Genes in Microbial Populations at Different Municipal Wastewater Treatment Plants in Germany

    Directory of Open Access Journals (Sweden)

    Norman Hembach

    2017-07-01

    Full Text Available Seven wastewater treatment plants (WWTPs with different population equivalents and catchment areas were screened for the prevalence of the colistin resistance gene mcr-1 mediating resistance against last resort antibiotic polymyxin E. The abundance of the plasmid-associated mcr-1 gene in total microbial populations during water treatment processes was quantitatively analyzed by qPCR analyses. The presence of the colistin resistance gene was documented for all of the influent wastewater samples of the seven WWTPs. In some cases the mcr-1 resistance gene was also detected in effluent samples of the WWTPs after conventional treatment reaching the aquatic environment. In addition to the occurrence of mcr-1 gene, CTX-M-32, blaTEM, CTX-M, tetM, CMY-2, and ermB genes coding for clinically relevant antibiotic resistances were quantified in higher abundances in all WWTPs effluents. In parallel, the abundances of Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli were quantified via qPCR using specific taxonomic gene markers which were detected in all influent and effluent wastewaters in significant densities. Hence, opportunistic pathogens and clinically relevant antibiotic resistance genes in wastewaters of the analyzed WWTPs bear a risk of dissemination to the aquatic environment. Since many of the antibiotic resistance gene are associated with mobile genetic elements horizontal gene transfer during wastewater treatment can't be excluded.

  13. Stability of U(VI) and Tc(VII) Reducing Microbial Communities to EnvironmentalPerturbation: Development and Testing of a Thermodynamic Network Model. Technical Report

    International Nuclear Information System (INIS)

    Jonathan D. Istok

    2008-01-01

    'Bioimmobilization' of redox-sensitive metals and radionuclides is being investigated as a way to remediate contaminated groundwater and sediments. In this approach, growth-limiting substrates are added to stimulate the activity of targeted groups of indigenous microorganisms and create conditions favorable for the microbially-mediated precipitation ('bioimmobilization') of targeted contaminants. This project investigated a fundamentally new approach for modeling this process that couples thermodynamic descriptions for microbial growth with associated geochemical reactions. In this approach, a synthetic microbial community is defined as a collection of defined microbial groups; each with a growth equation derived from bioenergetic principles. The growth equations and standard-state free energy yields are appended to a thermodynamic database for geochemical reactions and the combined equations are solved simultaneously to predict the effect of added substrates on microbial biomass, community composition, and system geochemistry. This approach, with a single set of thermodynamic parameters (one for each growth equation), was used to predict the results of laboratory and field bioimmobilization experiments at two geochemically diverse research sites. Predicted effects of ethanol or acetate addition on uranium and technetium solubility, major ion geochemistry, mineralogy, microbial biomass and community composition were in general agreement with experimental observations although the available experimental data precluded rigorous model testing. Model simulations provide insight into the long-standing difficulty in transferring experimental results from the laboratory to the field and from one field site to the next, especially if the form, concentration, or delivery of growth substrate is varied from one experiment to the next. Although originally developed for use in better understanding bioimmobilization of uranium and technetium via reductive precipitation, the

  14. Trichoderma harzianum MTCC 5179 impacts the population and functional dynamics of microbial community in the rhizosphere of black pepper (Piper nigrum L.).

    Science.gov (United States)

    Umadevi, Palaniyandi; Anandaraj, Muthuswamy; Srivastav, Vivek; Benjamin, Sailas

    2017-11-29

    Employing Illumina Hiseq whole genome metagenome sequencing approach, we studied the impact of Trichoderma harzianum on altering the microbial community and its functional dynamics in the rhizhosphere soil of black pepper (Piper nigrum L.). The metagenomic datasets from the rhizosphere with (treatment) and without (control) T. harzianum inoculation were annotated using dual approach, i.e., stand alone and MG-RAST. The probiotic application of T. harzianum in the rhizhosphere soil of black pepper impacted the population dynamics of rhizosphere bacteria, archae, eukaryote as reflected through the selective recruitment of bacteria [Acidobacteriaceae bacterium (p=1.24e-12), Candidatus koribacter versatilis (p=2.66e-10)] and fungi [(Fusarium oxysporum (p=0.013), Talaromyces stipitatus (p=0.219) and Pestalotiopsis fici (p=0.443)] in terms of abundance in population and bacterial chemotaxis (p=0.012), iron metabolism (p=2.97e-5) with the reduction in abundance for pathogenicity islands (p=7.30e-3), phages and prophages (p=7.30e-3) with regard to functional abundance. Interestingly, it was found that the enriched functional metagenomic signatures on phytoremediation such as benzoate transport and degradation (p=2.34e-4), and degradation of heterocyclic aromatic compounds (p=3.59e-13) in the treatment influenced the rhizosphere micro ecosystem favoring growth and health of pepper plant. The population dynamics and functional richness of rhizosphere ecosystem in black pepper influenced by the treatment with T. harzianum provides the ecological importance of T. harzianum in the cultivation of black pepper. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Distinct microbial populations are tightly linked to the profile of dissolved iron in the methanic sediments of the Helgoland mud area, North Sea

    Directory of Open Access Journals (Sweden)

    Oluwatobi Emmanuel Oni

    2015-05-01

    Full Text Available Iron reduction in subseafloor sulfate-depleted and methane-rich marine sediments is currently a subject of interest in subsurface geomicrobiology. While iron reduction and microorganisms involved have been well studied in marine surface sediments, little is known about microorganisms responsible for iron reduction in deep methanic sediments. Here, we used quantitative PCR (Q-PCR-based 16S rRNA gene copy numbers and pyrosequencing-based relative abundances of bacteria and archaea to investigate covariance between distinct microbial populations and specific geochemical profiles in the top 5 m of sediment cores from the Helgoland mud area, North Sea. We found that gene copy numbers of bacteria and archaea were specifically higher around the peak of dissolved iron in the methanic zone (250-350 cm. The higher copy numbers at these depths were also reflected by the relative sequence abundances of members of the candidate division JS1, methanogenic and Methanohalobium/ANME-3 related archaea. The distribution of these populations was strongly correlated to the profile of pore-water Fe2+ while that of Desulfobacteraceae corresponded to the pore-water sulfate profile. Furthermore, specific JS1 populations also strongly co-varied with the distribution of Methanosaetaceae in the methanic zone. Our data suggest that the interplay among JS1 bacteria, methanogenic archaea and Methanohalobium/ANME-3-related archaea may be important for iron reduction and methane cycling in deep methanic sediments of the Helgoland mud area and perhaps in other methane-rich depositional environments.

  16. Strategies to reduce exclusion among populations living in urban slum settlements in Bangladesh.

    Science.gov (United States)

    Rashid, Sabina Faiz

    2009-08-01

    The health and rights of populations living in informal or slum settlements are key development issues of the twenty-first century. As of 2007, the majority of the world's population lives in urban areas. More than one billion of these people, or one in three city-dwellers, live in inadequate housing with no or a few basic resources. In Bangladesh, urban slum settlements tend to be located in low-lying, flood-prone, poorly-drained areas, having limited formal garbage disposal and minimal access to safe water and sanitation. These areas are severely crowded, with 4-5 people living in houses of just over 100 sq feet. These conditions of high density of population and poor sanitation exacerbate the spread of diseases. People living in these areas experience social, economic and political exclusion, which bars them from society's basic resources. This paper overviews policies and actions that impact the level of exclusion of people living in urban slum settlements in Bangladesh, with a focus on improving the health and rights of the urban poor. Despite some strategies adopted to ensure better access to water and health, overall, the country does not have a comprehensive policy for urban slum residents, and the situation remains bleak.

  17. Strategies to Reduce Exclusion among Populations Living in Urban Slum Settlements in Bangladesh

    Science.gov (United States)

    2009-01-01

    The health and rights of populations living in informal or slum settlements are key development issues of the twenty-first century. As of 2007, the majority of the world's population lives in urban areas. More than one billion of these people, or one in three city-dwellers, live in inadequate housing with no or a few basic resources. In Bangladesh, urban slum settlements tend to be located in low-lying, flood-prone, poorly-drained areas, having limited formal garbage disposal and minimal access to safe water and sanitation. These areas are severely crowded, with 4–5 people living in houses of just over 100 sq feet. These conditions of high density of population and poor sanitation exacerbate the spread of diseases. People living in these areas experience social, economic and political exclusion, which bars them from society's basic resources. This paper overviews policies and actions that impact the level of exclusion of people living in urban slum settlements in Bangladesh, with a focus on improving the health and rights of the urban poor. Despite some strategies adopted to ensure better access to water and health, overall, the country does not have a comprehensive policy for urban slum residents, and the situation remains bleak. PMID:19761090

  18. Root-lesion nematodes suppress cabbage aphid population development by reducing aphid daily reproduction

    Directory of Open Access Journals (Sweden)

    W. H. Gera eHol

    2016-02-01

    Full Text Available Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modelling approach to analyse the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring per female per day in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring per female per day. The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments.

  19. Effects of Andrographis paniculata and Orthosiphon stamineus Supplementation on in-vivo Rumen Fermentation Parameters and Microbial Population in Goats Fed Urea-treated Rice Straw

    Directory of Open Access Journals (Sweden)

    Roslan, N.A.

    2016-12-01

    Full Text Available Four fistulated Boer cross-bred bucks with 25 kg average body weight was used to test the effects of dietary treated rice straw supplemented with A. paniculata and O. stamineus on in-vivo rumen parameters and microbial population in goats. The study was conducted in 4 periods (4 x 4 Latin square design, where each period was for a duration of 22 d; 10 dof adaptation period, 5 dof sampling and 7 dof change-over. The animals were fed once daily at 0800 (3% body weight with 60% of urea-treated rice straw and 40 % of one of four concentrate diets: T1-basal diet + 1% A. paniculata, T2-basal diet + 1% O. stamineus, T3-basal diet + 0.5% of A. paniculata and 0.5% O. stamineus (AO and T4-basal diet without supplementation of herbs. Clean water was provided ad libitum and the animals were individually penned. Rumen contents were sampled at 0, 2, 4, 6 and 12 hafter the onset feeding and the pH was recorded. Rumen pH, VFA's, concentration of ammonia and microbial population in the rumen fluid were measured. The mean rumen pH was the highest (P<0.05 at 2 h in T3 after the onset feeding while the mean concentration (mg/L of ammonia in the rumen fluid was the lowest at 6 and 12 h in T2 (P<0.05. The molar proportion of valerate was higher (P<0.05 at 6 h in T1. Meanwhile, the acetate to propionate ratio was affected by time where it was significantly higher at 12 h in T3. Significant reduction of total protozoa, methanogens, F. succinogens and R. albus number was observed in the herb-supplemented groups (P<0.05. The results suggest that urea-treated rice straw with herbs supplementation can be fed to goats without impairing their performance. However, further study could be done by increasing the supplementation of herbs in order to observe more effective results.

  20. Low-Temperature (10?C) Anaerobic Digestion of Dilute Dairy Wastewater in an EGSB Bioreactor: Microbial Community Structure, Population Dynamics, and Kinetics of Methanogenic Populations

    OpenAIRE

    Bialek, Katarzyna; Cysneiros, Denise; O'Flaherty, Vincent

    2013-01-01

    The feasibility of anaerobic digestion of dairy wastewater at 10?C was investigated in a high height?:?diameter ratio EGSB reactor. Stable performance was observed at an applied organic loading rate (OLR) of 0.5?2?kg?COD?m?3?d?1 with chemical oxygen demand (COD) removal efficiencies above 85%. When applied OLR increased to values above 2?kg?COD?m?3?d?1, biotreatment efficiency deteriorated, with methanogenesis being the rate-limiting step. The bioreactor recovered quickly (3 days) after reduc...

  1. Reductive immobilization of U(VI) in Fe(III) oxide-reducing subsurface sediments: Analysis of coupled microbial-geochemical processes in experimental reactive transport systems. Final Scientific/Technical Report-EMSP 73914

    International Nuclear Information System (INIS)

    Eric E. Roden Matilde M. Urrutia Mark O. Barnett Clifford R. Lange

    2005-01-01

    (VI) reduction is likely to be less efficient in natural soils and sediments than would be inferred from studies with synthetic Fe(III) oxides. A key implication of these findings is that production of Fe(II)-enriched sediments during one-time (or periodic) stimulation of DMRB activity is not likely to permit efficient long-term abiotic conversion of U(VI) to U(IV) in biogenic redox barriers designed to prevent far-field subsurface U(VI) migration. Instead our results suggest that ongoing DMRB activity will be required to achieve maximal U(VI) reduction efficiency, and emphasize the need for detailed understanding of patterns of DMRB growth, colonization, and maintenance in physically and chemically heterogeneous subsurface environments in order to predict the effectiveness of subsurface U(VI) bioremediation operations. A final ''capstone'' aspect of experimental work on the project was to examine the potential for sustained coupled Fe(III) oxide and U(VI) reduction in experimental flow-through reactor systems (i.e. sediment columns and ''semicontinuous culture'' systems) that are conceptually analogous to hydrologically-open subsurface environments. The results conclusively demonstrated the potential for sustained removal of U(VI) from solution via DMRB activity in excess of the U(VI) sorption capacity of the natural mineral assemblages as determined in abiotic controls. In addition, the abundance of sorbed U(VI) (a potential long-term source of U(VI) to the aqueous phase) was much lower in the biotic vs. abiotic systems. The latter results agree with other project findings which demonstrated the capacity for G. sulfurreducens to reduce sorbed U(VI). Throughout the project we have developed and refined a variety of reaction-based models of coupled Fe(III) oxide/U(VI) reduction, including a generalized model which accounts for the population dynamics of various respiratory microbial functional groups. These models have been employed in numerical simulations of both batch bench

  2. Physical activity reduces risk for colon polyps in a multiethnic colorectal cancer screening population

    Directory of Open Access Journals (Sweden)

    Sanchez Nelson F

    2012-06-01

    Full Text Available Abstract Background Identifying modifiable factors that influence the epidemiology of colorectal cancer incidence among multiethnic groups might be informative for the development of public health strategies targeting the disease. Minimal data exists describing the impact of physical activity on colorectal polyp risk in United States minority populations. The aim of this study is to evaluate the relationship of exercise on the prevalence of polyps in a multiethnic colorectal cancer screening population. Results We enrolled 982 patients: 558 Hispanic, 202 Asian,149 Black, and 69 White. Patients who reported exercising one or more hours weekly had a lower prevalence of any polyps (25.3% vs 33.2%, P = 0.008 as well as adenomas (13.8 vs. 18.9%, P = 0.03 compared to those who did not exercise. Black and Hispanic patients and those who were overweight or obese also had lower prevalence of polyps if they led an active lifestyle. Multivariate analysis revealed that age >55, male sex, and Black race/ethnicity were positively associated with the presence of adenomas, while a history of exercising one hour or more weekly was an independent negative predictor for the presence of adenomas anywhere in the colon (OR 0.67; 95% CI 0.4 - 0.9, P = 0.03. Conclusions Exercising one hour per week was associated with a lower prevalence of polyps and adenomas when compared to those who exercised less or not at all. An active lifestyle provides benefits to groups who are at risk for colorectal cancer, such as Blacks. It also provides significant protection to overweight and obese individuals. Public health initiatives should promote physical activity as a cancer prevention tool in multiethnic populations. Trial registration none

  3. French invasive Asian tiger mosquito populations harbor reduced bacterial microbiota and genetic diversity compared to Vietnamese autochthonous relatives

    Directory of Open Access Journals (Sweden)

    Guillaume eMinard

    2015-09-01

    Full Text Available The Asian tiger mosquito Aedes albopictus is one of the most significant pathogen vectors of the 21st century. Originating from Asia, it has invaded a wide range of eco-climatic regions worldwide. The insect-associated microbiota is now recognized to play a significant role in host biology. While genetic diversity bottlenecks are known to result from biological invasions, the resulting shifts in host-associated microbiota diversity has not been thoroughly investigated. To address this subject, we compared four autochthonous Ae. albopictus populations in Vietnam, the native area of Ae. albopictus, and three populations recently introduced to Metropolitan France, with the aim of documenting whether these populations display differences in host genotype and bacterial microbiota. Population-level genetic diversity (microsatellite markers and COI haplotype and bacterial diversity (16S rDNA metabarcoding were compared between field-caught mosquitoes. Bacterial microbiota from the whole insect bodies were largely dominated by Wolbachia pipientis. Targeted analysis of the gut microbiota revealed a greater bacterial diversity in which a fraction was common between French and Vietnamese populations. The genus Dysgonomonas was the most prevalent and abundant across all studied populations. Overall genetic diversities of both hosts and bacterial microbiota were significantly reduced in recently established populations of France compared to the autochthonous populations of Vietnam. These results open up many important avenues of investigation in order to link the process of geographical invasion to shifts in commensal and symbiotic microbiome communities, as such shifts may have dramatic impacts on the biology and/or vector competence of invading hematophagous insects.

  4. Willingness-to-pay for a population program aimed at reducing dietary salt in Denmark

    DEFF Research Database (Denmark)

    Kristiansen, Ivar Sønbø; Gyrd-Hansen, Dorte; Nexøe, Jørgen

    2006-01-01

    -74 was interviewed in-person in year 2000. They were asked how much they would be willing to contribute in additional tax for a population program that would half the intake of salt. The respondents were randomized to presentation of effectiveness format (number-needed-to-treat (NNT), relative risk reduction (RRR......), avoided cases of heart attack or increase in longevity). RESULTS: In total, 57% were unwilling to contribute to the program (63%, 51%, 51% and 63% in the NNT-, RRR-, case- and longevity-groups, respectively). The mean willingness-to-pay among the remaining 43% was $30 per person per month. While...

  5. Reducing bias in population and landscape genetic inferences: the effects of sampling related individuals and multiple life stages.

    Science.gov (United States)

    Peterman, William; Brocato, Emily R; Semlitsch, Raymond D; Eggert, Lori S

    2016-01-01

    In population or landscape genetics studies, an unbiased sampling scheme is essential for generating accurate results, but logistics may lead to deviations from the sample design. Such deviations may come in the form of sampling multiple life stages. Presently, it is largely unknown what effect sampling different life stages can have on population or landscape genetic inference, or how mixing life stages can affect the parameters being measured. Additionally, the removal of siblings from a data set is considered best-practice, but direct comparisons of inferences made with and without siblings are limited. In this study, we sampled embryos, larvae, and adult Ambystoma maculatum from five ponds in Missouri, and analyzed them at 15 microsatellite loci. We calculated allelic richness, heterozygosity and effective population sizes for each life stage at each pond and tested for genetic differentiation (F ST and D C ) and isolation-by-distance (IBD) among ponds. We tested for differences in each of these measures between life stages, and in a pooled population of all life stages. All calculations were done with and without sibling pairs to assess the effect of sibling removal. We also assessed the effect of reducing the number of microsatellites used to make inference. No statistically significant differences were found among ponds or life stages for any of the population genetic measures, but patterns of IBD differed among life stages. There was significant IBD when using adult samples, but tests using embryos, larvae, or a combination of the three life stages were not significant. We found that increasing the ratio of larval or embryo samples in the analysis of genetic distance weakened the IBD relationship, and when using D C , the IBD was no longer significant when larvae and embryos exceeded 60% of the population sample. Further, power to detect an IBD relationship was reduced when fewer microsatellites were used in the analysis.

  6. Reducing bias in population and landscape genetic inferences: the effects of sampling related individuals and multiple life stages

    Directory of Open Access Journals (Sweden)

    William Peterman

    2016-03-01

    Full Text Available In population or landscape genetics studies, an unbiased sampling scheme is essential for generating accurate results, but logistics may lead to deviations from the sample design. Such deviations may come in the form of sampling multiple life stages. Presently, it is largely unknown what effect sampling different life stages can have on population or landscape genetic inference, or how mixing life stages can affect the parameters being measured. Additionally, the removal of siblings from a data set is considered best-practice, but direct comparisons of inferences made with and without siblings are limited. In this study, we sampled embryos, larvae, and adult Ambystoma maculatum from five ponds in Missouri, and analyzed them at 15 microsatellite loci. We calculated allelic richness, heterozygosity and effective population sizes for each life stage at each pond and tested for genetic differentiation (FST and DC and isolation-by-distance (IBD among ponds. We tested for differences in each of these measures between life stages, and in a pooled population of all life stages. All calculations were done with and without sibling pairs to assess the effect of sibling removal. We also assessed the effect of reducing the number of microsatellites used to make inference. No statistically significant differences were found among ponds or life stages for any of the population genetic measures, but patterns of IBD differed among life stages. There was significant IBD when using adult samples, but tests using embryos, larvae, or a combination of the three life stages were not significant. We found that increasing the ratio of larval or embryo samples in the analysis of genetic distance weakened the IBD relationship, and when using DC, the IBD was no longer significant when larvae and embryos exceeded 60% of the population sample. Further, power to detect an IBD relationship was reduced when fewer microsatellites were used in the analysis.

  7. Effects of dietary inclusion of palm kernel cake on nutrient utilization, rumen fermentation characteristics and microbial populations of goats fed Paspalum plicatulum hay-based diet

    Directory of Open Access Journals (Sweden)

    Sahutaya Pongprayoon

    2010-12-01

    Full Text Available To investigate the effects of inclusion of palm kernel cake (PKC in the diets on intake, digestibility, rumen fermentationcharacteristics, nitrogen balance and microbial N supply, five goats (initial BW = 20±1 kg were randomly assigned to a55 Latin square design to receive five diets, T1 = concentrate with 15% PKC, T2 = 25% PKC, T3 = 35% PKC, T4 = 45% PKCand T5 = 55% PKC, of dietary dry matter, respectively. Plicatulum hay was offered ad libitum as the roughage. A metabolismtrial lasted for 21 days during which live weight changes and feed intakes were measured. Based on this experiment, therewere no significant differences (p>0.05 among treatment groups regarding dry matter (DM intake and digestion coefficientsof DM, organic matter, crude protein, neutral detergent fiber and acid detergent fiber, except in T4 and T5 (45 and 55% PKCwhich had lower (p0.05, however the concentration of total volatile fatty acids and protozoal populations were slightly lower forgoats fed inclusion of 45-55% PKC as compared with other treatments. Based on this experiment, it could be concluded thatthe optimal level of PKC in concentrate should be 15-35% for goats fed with plicatulum hay and that it may be an effectivemeans of exploiting the use of local feed resources for goat production.

  8. Antimicrobial activity of ceftaroline and other anti-infective agents against microbial pathogens recovered from the surgical intensive care patient population: a prevalence analysis.

    Science.gov (United States)

    Edmiston, Charles E; Krepel, Candace J; Leaper, David; Ledeboer, Nathan A; Mackey, Tami-Lea; Graham, Mary Beth; Lee, Cheong; Rossi, Peter J; Brown, Kellie R; Lewis, Brian D; Seabrook, Gary R

    2014-12-01

    Ceftaroline is a new parenteral cephalosporin agent with excellent activity against methicillin-sensitive (MSSA) and resistant strains of Staphylococcus aureus (MRSA). Critically ill surgical patients are susceptible to infection, often by multi-drug-resistant pathogens. The activity of ceftaroline against such pathogens has not been described. Three hundred thirty-five consecutive microbial isolates were collected from surgical wounds or abscesses, respiratory, urine, and blood cultures from patients in the surgical intensive care unit (SICU) of a major tertiary medical center. Using Clinical and Laboratory Standards Institute (CLSI) standard methodology and published breakpoints, all aerobic, facultative anaerobic isolates were tested against ceftaroline and selected comparative antimicrobial agents. All staphylococcal isolates were susceptible to ceftaroline at a breakpoint of ≤1.0 mcg/mL. In addition, ceftaroline exhibited excellent activity against all streptococcal clinical isolates and non-ESBL-producing strains of Enterobacteriaceae (93.5%) recovered from SICU patients. Ceftaroline was inactive against ESBL-producing Enterobacteriaceae, Pseudomonas aeruginosa, vancomycin-resistant enterococci, and selective gram-negative anaerobic bacteria. At present, ceftaroline is the only cephalosporin agent that is active against community and healthcare-associated MRSA. Further studies are needed to validate the benefit of this novel broad-spectrum anti-infective agent for the treatment of susceptible serious infections in the SICU patient population.

  9. Performance, carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater: Effect of hydraulic retention time (HRT) and organic loading rate (OLR).

    Science.gov (United States)

    Liu, Shuli; Zhang, Guangming; Zhang, Jie; Li, Xiangkun; Li, Jianzheng

    2016-01-01

    Effects of hydraulic retention time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB (Rhodopseudomonas palustris)-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48h and OLR of 2.51g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3mg/L and 3.91mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Addiction Potential of Cigarettes With Reduced Nicotine Content in Populations With Psychiatric Disorders and Other Vulnerabilities to Tobacco Addiction.

    Science.gov (United States)

    Higgins, Stephen T; Heil, Sarah H; Sigmon, Stacey C; Tidey, Jennifer W; Gaalema, Diann E; Hughes, John R; Stitzer, Maxine L; Durand, Hanna; Bunn, Janice Y; Priest, Jeff S; Arger, Christopher A; Miller, Mollie E; Bergeria, Cecilia L; Davis, Danielle R; Streck, Joanna M; Reed, Derek D; Skelly, Joan M; Tursi, Lauren

    2017-10-01

    A national policy is under consideration to reduce the nicotine content of cigarettes to lower nicotine addiction potential in the United States. To examine how smokers with psychiatric disorders and other vulnerabilities to tobacco addiction respond to cigarettes with reduced nicotine content. A multisite, double-blind, within-participant assessment of acute response to research cigarettes with nicotine content ranging from levels below a hypothesized addiction threshold to those representative of commercial cigarettes (0.4, 2.3, 5.2, and 15.8 mg/g of tobacco) at 3 academic sites included 169 daily smokers from the following 3 vulnerable populations: individuals with affective disorders (n = 56) or opioid dependence (n = 60) and socioeconomically disadvantaged women (n = 53). Data were collected from March 23, 2015, through April 25, 2016. After a brief smoking abstinence, participants were exposed to the cigarettes with varying nicotine doses across fourteen 2- to 4-hour outpatient sessions. Addiction potential of the cigarettes was assessed using concurrent choice testing, the Cigarette Purchase Task (CPT), and validated measures of subjective effects, such as the Minnesota Nicotine Withdrawal Scale. Among the 169 daily smokers included in the analysis (120 women [71.0%] and 49 men [29.0%]; mean [SD] age, 35.6 [11.4] years), reducing the nicotine content of cigarettes decreased the relative reinforcing effects of smoking in all 3 populations. Across populations, the 0.4-mg/g dose was chosen significantly less than the 15.8-mg/g dose in concurrent choice testing (mean [SEM] 30% [0.04%] vs 70% [0.04%]; Cohen d = 0.40; P vulnerable to tobacco addiction. Smokers with psychiatric conditions and socioeconomic disadvantage are more addicted and less likely to quit and experience greater adverse health impacts. Policies to reduce these disparities are needed; reducing the nicotine content in cigarettes should be a policy focus.

  11. Efficacy of a 2% climbazole shampoo for reducing Malassezia population sizes on the skin of naturally infected dogs.

    Science.gov (United States)

    Cavana, P; Petit, J-Y; Perrot, S; Guechi, R; Marignac, G; Reynaud, K; Guillot, J

    2015-12-01

    Shampoo therapy is often recommended for the control of Malassezia overgrowth in dogs. The aim of this study was to evaluate the in vivo activity of a 2% climbazole shampoo against Malassezia pachydermatis yeasts in naturally infected dogs. Eleven research colony Beagles were used. The dogs were distributed randomly into two groups: group A (n=6) and group B (n=5). Group A dogs were washed with a 2% climbazole shampoo, while group B dogs were treated with a physiological shampoo base. The shampoos were applied once weekly for two weeks. The population size of Malassezia yeasts on skin was determined by fungal culture through modified Dixon's medium contact plates pressed on left concave pinna, axillae, groins, perianal area before and after shampoo application. Samples collected were compared by Wilcoxon rank sum test. Samples collected after 2% climbazole shampoo application showed a significant and rapid reduction of Malassezia population sizes. One hour after the first climbazole shampoo application, Malassezia reduction was already statistically significant and 15 days after the second climbazole shampoo, Malassezia population sizes were still significantly decreased. No significant reduction of Malassezia population sizes was observed in group B dogs. The application of a 2% climbazole shampoo significantly reduced Malassezia population sizes on the skin of naturally infected dogs. Application of 2% climbazole shampoo may be useful for the control of Malassezia overgrowth and it may be also proposed as prevention when recurrences are frequent. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Effect of Dietary Supplementation of Red Ginseng By-product on Laying Performance, Blood Biochemistry, Serum Immunoglobulin and Microbial Population in Laying Hens.

    Science.gov (United States)

    Kang, H K; Park, S-B; Kim, C H

    2016-10-01

    This study was carried out to investigate the effect of dietary supplementation of red ginseng by-product (RGB) on the laying performance, blood biochemistry, and microbial population in laying hens. A total of 120 Hy-Line Brown laying hens (75 weeks old) were randomly allotted to 1 of 3 dietary treatments with 4 replicates per treatment. A commercial-type basal diet was prepared, and 2 additional diets were prepared by supplementing 5.0 or 10.0 g/kg of RGB to the basal diet at the expense of corn. The diets were fed to hens on an ad libitum basis for 4 weeks. There were no differences in feed intake, egg weight, and feed conversion ratio during 4 weeks of the feeding trial. However, hen-day egg production was significantly greater (p<0.05) for the RGB treatment groups than that for the basal treatment group. There were no differences in triglyceride, aspartate aminotransferase, and alanine aminotransferase during the 4-week feeding trial. However, RGB supplementation increased (p<0.05) the serum immunoglobulin G (IgG) and IgM content compared with basal treatment group. The total cholesterol was lower (p<0.05) in the RGB treatments groups than that in the basal treatment group. The intestinal Lactobacillus population was greater (p<0.05) for the RGB treatments groups than that for the basal treatment group. However, the numbers of Salmonella and Escherichia coli were not different among dietary treatments. During the entire experiment, there was no significant difference in egg quality among all the treatments. In conclusion, in addition to improving hen-day production, there were positive effects of dietary RGB supplementation on serum immunoglobulin and cholesterol levels in laying hens.

  13. Mineralogic control on abundance and diversity of surface-adherent microbial communities

    Science.gov (United States)

    Mauck, Brena S.; Roberts, Jennifer A.

    2007-01-01

    In this study, we investigated the role of mineral-bound P and Fe in defining microbial abundance and diversity in a carbon-rich groundwater. Field colonization experiments of initially sterile mineral surfaces were combined with community structure characterization of the attached microbial population. Silicate minerals containing varying concentrations of P (∼1000 ppm P) and Fe (∼4 wt % Fe 2 O3), goethite (FeOOH), and apatite [Ca5(PO4)3(OH)] were incubated for 14 months in three biogeochemically distinct zones within a petroleum-contaminated aquifer. Phospholipid fatty acid analysis of incubated mineral surfaces and groundwater was used as a measure of microbial community structure and biomass. Microbial biomass on minerals exhibited distinct trends as a function of mineralogy depending on the environment of incubation. In the carbon-rich, aerobic groundwater attached biomass did not correlate to the P- or Fe- content of the mineral. In the methanogenic groundwater, however, biomass was most abundant on P-containing minerals. Similarly, in the Fe-reducing groundwater a correlation between Fe-content and biomass was observed. The community structure of the mineral-adherent microbial population was compared to the native groundwater community. These two populations were significantly different regardless of mineralogy, suggesting differentiation of the planktonic community through attachment, growth, and death of colonizing cells. Biomarkers specific for dissimilatory Fe-reducing bacteria native to the aquifer were identified only on Fe-containing minerals in the Fe-reducing groundwater. These results demonstrate that the trace nutrient content of minerals affects both the abundance and diversity of surface-adherent microbial communities. This behavior may be a means to access limiting nutrients from the mineral, creating a niche for a particular microbial population. These results suggest that heterogeneity of microbial populations and their associated

  14. Application of the Central Limit Theorem in microbial risk assessment: High number of serving reduces the Coefficient of Variation of food-borne burden-of-illness

    NARCIS (Netherlands)

    Pérez-Rodríguez, F.; Zwietering, M.H.

    2012-01-01

    The Central Limit Theorem (CLT) is proposed as a means of understanding microbial risk in foods from a Public Health perspective. One variant of the CLT states that as the number of random variables, each with a finite mean and variance, increases (¿8), the distribution of the sum (or mean) of those

  15. Combined effects of reduced irrigation and water quality on the soil microbial community of a citrus orchard under semi-arid conditions

    Czech Academy of Sciences Publication Activity Database

    Bastida, F.; Torres, I.F.; Romero-Trigueros, C.; Baldrian, Petr; Větrovský, Tomáš; Bayona, J.M.; Alarcón, J.J.; Hernandéz, T.; García, C.; Nikolás, E.

    2017-01-01

    Roč. 104, JAN 2017 (2017), s. 226-237 ISSN 0038-0717 Institutional support: RVO:61388971 Keywords : Microbial biomass * Bacterial diversity * Enzyme activities Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.857, year: 2016

  16. Reducing NIR prediction errors with nonlinear methods and large populations of intact compound feedstuffs

    International Nuclear Information System (INIS)

    Fernández-Ahumada, E; Gómez, A; Vallesquino, P; Guerrero, J E; Pérez-Marín, D; Garrido-Varo, A; Fearn, T

    2008-01-01

    According to the current demands of the authorities, the manufacturers and the consumers, controls and assessments of the feed compound manufacturing process have become a key concern. Among others, it must be assured that a given compound feed is well manufactured and labelled in terms of the ingredient composition. When near-infrared spectroscopy (NIRS) together with linear models were used for the prediction of the ingredient composition, the results were not always acceptable. Therefore, the performance of nonlinear methods has been investigated. Artificial neural networks and least squares support vector machines (LS-SVM) have been applied to a large (N = 20 320) and heterogeneous population of non-milled feed compounds for the NIR prediction of the inclusion percentage of wheat and sunflower meal, as representative of two different classes of ingredients. Compared to partial least squares regression, results showed considerable reductions of standard error of prediction values for both methods and ingredients: reductions of 45% with ANN and 49% with LS-SVM for wheat and reductions of 44% with ANN and 46% with LS-SVM for sunflower meal. These improvements together with the facility of NIRS technology to be implemented in the process make it ideal for meeting the requirements of the animal feed industry

  17. Reduced Spill at Hydropower Dams: Opportunities for More Generation and Increased Fish Population

    Energy Technology Data Exchange (ETDEWEB)

    Coutant, Charles C [ORNL; Mann, Roger [RMecon, Davis, California; Sale, Michael J [ORNL

    2006-09-01

    This report indicates that reduction of managed spill at hydropower dams can speed implementation of technologies for fish protection and achieve economic goals. Spill of water over spillways is managed in the Columbia River basin to assist downstream-migrating juvenile salmon, and is generally believed to be the most similar to natural migration, benign and effective passage route; other routes include turbines, intake screens with bypasses, and surface bypasses. However, this belief may be misguided, because spill is becoming recognized as less than natural, with deep intakes below normal migration depths, and likely causing physical damages from severe shear on spillways, high turbulence in tail waters, and collisions with baffle blocks that lead to disorientation and predation. Some spillways induce mortalities comparable to turbines. Spill is expensive in lost generation, and controversial. Fish-passage research is leading to more fish-friendly turbines, screens and bypasses that are more effective and less damaging, and surface bypasses that offer passage of more fish per unit water volume than does spill (leaving more water for generation). Analyses by independent economists demonstrated that goals of increased fish survival over the long term and net gain to the economy can be obtained by selectively reducing spill and diverting some of the income from added power generation to research, development, and installation of fish-passage technologies. Such a plan would selectively reduce spill when and where least damaging to fish, increase electricity generation using the water not spilled and use innovative financing to direct monetary gains to improving fish passage.

  18. Variant in GALNT3 Gene Linked with Reduced Coronary Artery Disease Risk in Chinese Population.

    Science.gov (United States)

    Guo, Liwei; Li, Duan; Li, Mengting; Li, Lin; Huang, Yanmei

    2017-07-01

    Our previous study found expression of GALNT3 gene was reduced in coronary artery disease (CAD) patients, and it contributed to endothelial injury by regulating apoptosis and matrix metalloproteinase (MMP) expression. GALNT3 gene may be a potential target for future therapeutic intervention of CAD. However, none reports linking the GALNT3 gene to susceptibility of CAD. This study investigated the variant associations of GALNT3 gene and CAD. Thirteen single nucleotide polymorphism (SNP) in and around the GALNT3 gene were tagged and analyzed in CAD patients (n = 1515) and control individuals (n = 5019), and the SNPs with CAD were tested with multiple logistic regression analysis in an additive genetic model (with one degree of freedom) after adjusting for age and sex. Expression of GALNT3 gene was detected by real-time PCR and Western blot. Luciferase reporter assays were used to detect the allele-specific effect of rs4621175 on transcriptional activity. Two GALNT3 markers, rs13427924 and rs4621175, were significantly associated with CAD (odds ratio [OR] = 0.87, p = 1.01 × 10 -3 and OR = 0.75, p = 2.51 × 10 -4 , respectively), and the risk A allele of rs4621175 was associated with lower GALNT3 expression in both mRNA and protein level; also, A allele showed decreased reporter activity. In addition, we found the level of GALNT3 negatively correlated with MMP-2 gene expression. This study identified GALNT3 as a novel gene that rendered patients susceptible to CAD, and the A allele of a disease-associated variant rs4621175 linked reduced CAD risk through decreased GALNT3 expression. These results confirmed the role of GALNT3 gene in CAD and provided new insights into the genetic regulation of the GALNT3 gene with respect to the pathogenesis of CAD.

  19. Personalised digital interventions for reducing hazardous and harmful alcohol consumption in community-dwelling populations.

    Science.gov (United States)

    Kaner, Eileen Fs; Beyer, Fiona R; Garnett, Claire; Crane, David; Brown, Jamie; Muirhead, Colin; Redmore, James; O'Donnell, Amy; Newham, James J; de Vocht, Frank; Hickman, Matthew; Brown, Heather; Maniatopoulos, Gregory; Michie, Susan

    2017-09-25

    Excessive alcohol use contributes significantly to physical and psychological illness, injury and death, and a wide array of social harm in all age groups. A proven strategy for reducing excessive alcohol consumption levels is to offer a brief conversation-based intervention in primary care settings, but more recent technological innovations have enabled people to interact directly via computer, mobile device or smartphone with digital interventions designed to address problem alcohol consumption. To assess the effectiveness and cost-effectiveness of digital interventions for reducing hazardous and harmful alcohol consumption, alcohol-related problems, or both, in people living in the community, specifically: (i) Are digital interventions more effective and cost-effective than no intervention (or minimal input) controls? (ii) Are digital interventions at least equally effective as face-to-face brief alcohol interventions? (iii) What are the effective component behaviour change techniques (BCTs) of such interventions and their mechanisms of action? (iv) What theories or models have been used in the development and/or evaluation of the intervention? Secondary objectives were (i) to assess whether outcomes differ between trials where the digital intervention targets participants attending health, social care, education or other community-based settings and those where it is offered remotely via the internet or mobile phone platforms; (ii) to specify interventions according to their mode of delivery (e.g. functionality features) and assess the impact of mode of delivery on outcomes. We searched CENTRAL, MEDLINE, PsycINFO, CINAHL, ERIC, HTA and Web of Knowledge databases; ClinicalTrials.com and WHO ICTRP trials registers and relevant websites to April 2017. We also checked the reference lists of included trials and relevant systematic reviews. We included randomised controlled trials (RCTs) that evaluated the effectiveness of digital interventions compared with no

  20. Comparative efficacies of oral ketoconazole and terbinafine for reducing Malassezia population sizes on the skin of Basset Hounds.

    Science.gov (United States)

    Guillot, Jacques; Bensignor, Emmanuel; Jankowski, François; Seewald, Wolfgang; Chermette, René; Steffan, Jean

    2003-06-01

    The objective of this study was to compare the efficacy of oral ketoconazole and terbinafine for reducing population sizes of Malassezia yeasts on canine skin. Twenty-one Basset Hounds were randomised in three groups of seven according to Malassezia populations. Dogs in the first group were treated by oral administration of ketoconazole (Ketofungol) 200 mg, Janssen-Cilag) at 10 mg x kg-1, every 24 h with food, for 3 weeks. Dogs in the second group were treated by oral administration of terbinafine (Lamisil) 250 mg, Novartis) at 30 mg x kg-1, every 24 h with food, for 3 weeks. The seven remaining dogs were used as controls. Malassezia population sizes were assessed by use of contact plates on four cutaneous sites at days 7, 14 and 21. Both ketoconazole and terbinafine were effective in reducing the baseline levels of Malassezia organisms with no significant difference between the two drugs. In further studies, oral terbinafine should be evaluated for the management of canine cases of Malassezia dermatitis.

  1. Assessing Progress in Reducing the At-Risk Population after 13 Years of the Global Programme to Eliminate Lymphatic Filariasis

    Science.gov (United States)

    Hooper, Pamela J.; Chu, Brian K.; Mikhailov, Alexei; Ottesen, Eric A.; Bradley, Mark

    2014-01-01

    Background In 1997, the World Health Assembly adopted Resolution 50.29, committing to the elimination of lymphatic filariasis (LF) as a public health problem, subsequently targeted for 2020. The initial estimates were that 1.2 billion people were at-risk for LF infection globally. Now, 13 years after the Global Programme to Eliminate Lymphatic Filariasis (GPELF) began implementing mass drug administration (MDA) against LF in 2000—during which over 4.4 billion treatments have been distributed in 56 endemic countries—it is most appropriate to estimate the impact that the MDA has had on reducing the population at risk of LF. Methodology/Principal Findings To assess GPELF progress in reducing the population at-risk for LF, we developed a model based on defining reductions in risk of infection among cohorts of treated populations following each round of MDA. The model estimates that the number of people currently at risk of infection decreased by 46% to 789 million through 2012. Conclusions/Significance Important progress has been made in the global efforts to eliminate LF, but significant scale-up is required over the next 8 years to reach the 2020 elimination goal. PMID:25411843

  2. A Population Approach to Transportation Planning: Reducing Exposure to Motor-Vehicles

    Directory of Open Access Journals (Sweden)

    Daniel Fuller

    2013-01-01

    Full Text Available Transportation planning and public health have important historical roots. To address common challenges, including road traffic fatalities, integration of theories and methods from both disciplines is required. This paper presents an overview of Geoffrey Rose's strategy of preventive medicine applied to road traffic fatalities. One of the basic principles of Rose's strategy is that a large number of people exposed to a small risk can generate more cases than a small number exposed to a high risk. Thus, interventions should address the large number of people exposed to the fundamental causes of diseases. Exposure to moving vehicles could be considered a fundamental cause of road traffic deaths and injuries. A global reduction in the amount of kilometers driven would result in a reduction of the likelihood of collisions for all road users. Public health and transportation research must critically appraise their practice and engage in informed dialogue with the objective of improving mobility and productivity while simultaneously reducing the public health burden of road deaths and injuries.

  3. Task oriented training improves the balance outcome & reducing fall risk in diabetic population.

    Science.gov (United States)

    Ghazal, Javeria; Malik, Arshad Nawaz; Amjad, Imran

    2016-01-01

    The objective was to determine the balance impairments and to compare task oriented versus traditional balance training in fall reduction among diabetic patients. The randomized control trial with descriptive survey and 196 diabetic patients were recruited to assess balance impairments through purposive sampling technique. Eighteen patients were randomly allocated into two groups; task oriented balance training group TOB (n=8) and traditional balance training group TBT (n=10). The inclusion criteria were 30-50 years age bracket and diagnosed cases of Diabetes Mellitus with neuropathy. The demographics were taken through standardized & valid assessment tools include Berg Balance Scale and Functional Reach Test. The measurements were obtained at baseline, after 04 and 08 weeks of training. The mean age of the participants was 49 ±6.79. The result shows that 165(84%) were at moderate risk of fall and 31(15%) were at mild risk of fall among total 196 diabetic patients. There was significant improvement (p balance training group for dynamic balance, anticipatory balance and reactive balance after 8 weeks of training as compare to traditional balance training. Task oriented balance training is effective in improving the dynamic, anticipator and reactive balance. The task oriented training reduces the risk of falling through enhancing balance outcome.

  4. Effect of dietary supplementation with Rhizopus oryzae or Chrysonilia crassa on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

    OpenAIRE

    S. Sugiharto; T. Yudiarti; I. Isroli; E. Widiastuti; F. D. Putra

    2017-01-01

    Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS) on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from...

  5. Retinitis pigmentosa reduces the risk of proliferative diabetic retinopathy: a nationwide population-based cohort study.

    Directory of Open Access Journals (Sweden)

    Yuh-Fang Chen

    Full Text Available PURPOSE: To study the association between retinitis pigmentosa (RP and the progression of diabetic retinopathy (DR. METHODS: Using the Longitudinal Health Insurance Database 2000 of Taiwan, we identified individuals with an initial diagnosis for RP during the period of 1997-2008. A non-RP comparison group, 10-fold frequency matched by sex, age, index year and the year of diabetes diagnosed, were randomly selected from the same database. The occurrence of DR was observed for all subjects until the end of 2009. The Kaplan-Meier curves were used to illustrate the cumulative probability of developing DR for the RP group and comparison groups. The hazard ratio (HR of DR for the RP group relative to the comparison group was estimated using Cox proportional hazards model after adjusting for potential confounders. RESULTS: The Kaplan-Meier curves were not statistically significant different between the RP group and the comparison group. However, the RP group had a higher cumulative probability of developing DR during the first six to seven years. The cumulative probability kept increasing and became higher in the comparison group but remained unchanged in the RP group. The HR for the RP patients comparing with the comparison group was 0.96 (95% confidence interval (CI = 0.43-2.14. Stratified by severity, RP was associated with a non-statistically significant reduced risk of proliferative DR (PDR (HR = 0.70, 95% CI = 0.16-3.14. The HR for non-proliferative DR (NPDR was 1.08 (95% CI = 0.40-2.86. CONCLUSION: In this study, RP was not statistically significant associated with the incidence of DR.

  6. A persistent mitochondrial deletion reduces fitness and sperm performance in heteroplasmic populations of C. elegans

    Directory of Open Access Journals (Sweden)

    Chin Kara

    2007-03-01

    Full Text Available Abstract Background Mitochondrial DNA (mtDNA mutations are of increasing interest due to their involvement in aging, disease, fertility, and their role in the evolution of the mitochondrial genome. The presence of reactive oxygen species and the near lack of repair mechanisms cause mtDNA to mutate at a faster rate than nuclear DNA, and mtDNA deletions are not uncommon in the tissues of individuals, although germ-line mtDNA is largely lesion-free. Large-scale deletions in mtDNA may disrupt multiple genes, and curiously, some large-scale deletions persist over many generations in a heteroplasmic state. Here we examine the phenotypic effects of one such deletion, uaDf5, in Caenorhabditis elegans (C. elegans. Our study investigates the phenotypic effects of this 3 kbp deletion. Results The proportion of uaDf5 chromosomes in worms was highly heritable, although uaDf5 content varied from worm to worm and within tissues of individual worms. We also found an impact of the uaDf5 deletion on metabolism. The deletion significantly reduced egg laying rate, defecation rate, and lifespan. Examination of sperm bearing the uaDf5 deletion revealed that sperm crawled more slowly, both in vitro and in vivo. Conclusion Worms harboring uaDf5 are at a selective disadvantage compared to worms with wild-type mtDNA. These effects should lead to the rapid extinction of the deleted chromosome, but it persists indefinitely. We discuss both the implications of this phenomenon and the possible causes of a shortened lifespan for uaDf5 mutant worms.

  7. A Case Report: Cornerstone Health Care Reduced the Total Cost of Care Through Population Segmentation and Care Model Redesign.

    Science.gov (United States)

    Green, Dale E; Hamory, Bruce H; Terrell, Grace E; O'Connell, Jasmine

    2017-08-01

    Over the course of a single year, Cornerstone Health Care, a multispecialty group practice in North Carolina, redesigned the underlying care models for 5 of its highest-risk populations-late-stage congestive heart failure, oncology, Medicare-Medicaid dual eligibles, those with 5 or more chronic conditions, and the most complex patients with multiple late-stage chronic conditions. At the 1-year mark, the results of the program were analyzed. Overall costs for the patients studied were reduced by 12.7% compared to the year before enrollment. All fully implemented programs delivered between 10% and 16% cost savings. The key area for savings factor was hospitalization, which was reduced by 30% across all programs. The greatest area of cost increase was "other," a category that consisted in large part of hospice services. Full implementation was key; 2 primary care sites that reverted to more traditional models failed to show the same pattern of savings.

  8. Equity impact of population-level interventions and policies to reduce smoking in adults: a systematic review.

    Science.gov (United States)

    Brown, Tamara; Platt, Stephen; Amos, Amanda

    2014-05-01

    There is strong evidence about which tobacco control policies reduce smoking. However, their equity impact is uncertain. The aim was to assess the effectiveness of population-level interventions/policies to reduce socioeconomic inequalities in adult smoking. Systematic review of studies of population-level interventions/policies reporting smoking-related outcomes in adults of lower compared to higher socioeconomic status (SES). References were screened and independently checked. Studies were quality assessed. Results are presented in a narrative synthesis. Equity impact was assessed as: positive (reduced inequality), neutral (no difference by SES), negative (increased inequality), mixed (equity impact varied) or unclear. 117 studies of 130 interventions/policies were included: smokefree (44); price/tax (27); mass media campaigns (30); advertising controls (9); cessation support (9); settings-based interventions (7); multiple policies (4). The distribution of equity effects was: 33 positive, 36 neutral, 38 negative, 6 mixed, 17 unclear. Most neutral equity studies benefited all SES groups. Fourteen price/tax studies were equity positive. Voluntary, regional and partial smokefree policies were more likely to be equity negative than national, comprehensive smokefree policies. Mass media campaigns had inconsistent equity effects. Cigarette marketing controls were equity positive or neutral. Targeted national smoking cessation services can be equity positive by achieving higher reach among low SES, compensating for lower quit rates. Few studies have assessed the equity impact of tobacco control policy/interventions. Price/tax increases had the most consistent positive equity impact. More research is needed to strengthen the evidence-base for reducing smoking inequalities and to develop effective equity-orientated tobacco control strategies. Copyright © 2014. Published by Elsevier Ireland Ltd.

  9. Epigeic earthworms exert a bottleneck effect on microbial communities through gut associated processes.

    Science.gov (United States)

    Gómez-Brandón, María; Aira, Manuel; Lores, Marta; Domínguez, Jorge

    2011-01-01

    Earthworms play a critical role in organic matter decomposition because of the interactions they establish with microorganisms. The ingestion, digestion, assimilation of organic material in the gut and then casting is the first step in earthworm-microorganism interactions. The current knowledge of these direct effects is still limited for epigeic earthworm species, mainly those living in man-made environments. Here we tested whether and to what extent the earthworm Eisenia andrei is capable of altering the microbiological properties of fresh organic matter through gut associated processes; and if these direct effects are related to the earthworm diet. To address these questions we determined the microbial community structure (phospholipid fatty acid profiles) and microbial activity (fluorescein diacetate hydrolysis) in the earthworm casts derived from three types of animal manure (cow, horse and pig manure), which differed in microbial composition. The passage of the organic material through the gut of E. andrei reduced the total microbial biomass irrespective of the type of manure, and resulted in a decrease in bacterial biomass in all the manures; whilst leaving the fungi unaffected in the egested materials. However, unlike the microbial biomass, no such reduction was detected in the total microbial activity of cast samples derived from the pig manure. Moreover, no differences were found between cast samples derived from the different types of manure with regards to microbial community structure, which provides strong evidence for a bottleneck effect of worm digestion on microbial populations of the original material consumed. Our data reveal that earthworm gut is a major shaper of microbial communities, thereby favouring the existence of a reduced but more active microbial population in the egested materials, which is of great importance to understand how biotic interactions within the decomposer food web influence on nutrient cycling.

  10. Epigeic earthworms exert a bottleneck effect on microbial communities through gut associated processes.

    Directory of Open Access Journals (Sweden)

    María Gómez-Brandón

    Full Text Available BACKGROUND: Earthworms play a critical role in organic matter decomposition because of the interactions they establish with microorganisms. The ingestion, digestion, assimilation of organic material in the gut and then casting is the first step in earthworm-microorganism interactions. The current knowledge of these direct effects is still limited for epigeic earthworm species, mainly those living in man-made environments. Here we tested whether and to what extent the earthworm Eisenia andrei is capable of altering the microbiological properties of fresh organic matter through gut associated processes; and if these direct effects are related to the earthworm diet. METHODOLOGY: To address these questions we determined the microbial community structure (phospholipid fatty acid profiles and microbial activity (fluorescein diacetate hydrolysis in the earthworm casts derived from three types of animal manure (cow, horse and pig manure, which differed in microbial composition. PRINCIPAL FINDINGS: The passage of the organic material through the gut of E. andrei reduced the total microbial biomass irrespective of the type of manure, and resulted in a decrease in bacterial biomass in all the manures; whilst leaving the fungi unaffected in the egested materials. However, unlike the microbial biomass, no such reduction was detected in the total microbial activity of cast samples derived from the pig manure. Moreover, no differences were found between cast samples derived from the different types of manure with regards to microbial community structure, which provides strong evidence for a bottleneck effect of worm digestion on microbial populations of the original material consumed. CONCLUSIONS/SIGNIFICANCE: Our data reveal that earthworm gut is a major shaper of microbial communities, thereby favouring the existence of a reduced but more active microbial population in the egested materials, which is of great importance to understand how biotic interactions

  11. Microbially produced phytotoxins and plant disease management ...

    African Journals Online (AJOL)

    Nowadays, these evaluation techniques are becoming an important complement to classical breeding methods. The knowledge of the inactivation of microbial toxins has led to the use of microbial enzymes to inactivate phytotoxins thereby reducing incidence and severity of disease induced by microbial toxins. Considering ...

  12. To Treat or to Prevent?: Reducing the Population Burden of Violence-related Post-traumatic Stress Disorder.

    Science.gov (United States)

    Cerdá, Magdalena; Tracy, Melissa; Keyes, Katherine M; Galea, Sandro

    2015-09-01

    Violence-related post-traumatic stress disorder (PTSD) remains a prevalent and disabling psychiatric disorder in urban areas. However, the most effective allocation of resources into prevention and treatment to reduce this problem is unknown. We contrasted the impact of two interventions on violence-related PTSD: (1) a population-level intervention intended to prevent violence (i.e., hot-spot policing), and (2) an individual-level intervention intended to shorten PTSD duration (i.e., cognitive-behavioral therapy-CBT). We used agent-based modeling to simulate violence and PTSD in New York City under four scenarios: (1) no intervention, (2) targeted policing to hot spots of violence, (3) increased access to CBT for people who suffered from violence-related PTSD, and (4) a combination of the two interventions. Combined prevention and treatment produced the largest decrease in violence-related PTSD prevalence: hot-spot policing plus a 50% increase in CBT for 5 years reduced the annual prevalence of violence-related PTSD from 3.6% (95% confidence interval = 3.5%, 3.6%) to 3.4% (3.3%, 3.5%). It would have been necessary to implement hot-spot policing or to increase CBT by 200% for 10 years for either intervention to achieve the same reduction in isolation. This study provides an empirically informed demonstration that investment in combined strategies that target social determinants of mental illness and provide evidence-based treatment to those affected by psychiatric disorders can produce larger reductions in the population burden from violence-related PTSD than either preventive or treatment interventions alone. However, neither hot-spot policing nor CBT, alone or combined, will produce large shifts in the population prevalence of violence-related PTSD.

  13. Public health economic evaluation of different European Union-level policy options aimed at reducing population dietary trans fat intake.

    Science.gov (United States)

    Martin-Saborido, Carlos; Mouratidou, Theodora; Livaniou, Anastasia; Caldeira, Sandra; Wollgast, Jan

    2016-11-01

    The adverse relation between dietary trans fatty acid (TFA) intake and coronary artery disease risk is well established. Many countries in the European Union (EU) and worldwide have implemented different policies to reduce the TFA intake of their populations. The aim of this study was to assess the added value of EU-level action by estimating the cost-effectiveness of 3 possible EU-level policy measures to reduce population dietary TFA intake. This was calculated against a reference situation of not implementing any EU-level policy (i.e., by assuming only national or self-regulatory measures). We developed a mathematical model to compare different policy options at the EU level: 1) to do nothing beyond the current state (reference situation), 2) to impose mandatory TFA labeling of prepackaged foods, 3) to seek voluntary agreements toward further reducing industrially produced TFA (iTFA) content in foods, and 4) to impose a legislative limit for iTFA content in foods. The model indicated that to impose an EU-level legal limit or to make voluntary agreements may, over the course of a lifetime (85 y), avoid the loss of 3.73 and 2.19 million disability-adjusted life-years (DALYs), respectively, and save >51 and 23 billion euros when compared with the reference situation. Implementing mandatory TFA labeling can also avoid the loss of 0.98 million DALYs, but this option incurs more costs than it saves compared with the reference option. The model indicates that there is added value of an EU-level action, either via a legal limit or through voluntary agreements, with the legal limit option producing the highest additional health benefits. Introducing mandatory TFA labeling for the EU common market may provide some additional health benefits; however, this would likely not be a cost-effective strategy.

  14. Dietary pattern derived by reduced rank regression and depressive symptoms in a multi-ethnic population: the HELIUS study.

    Science.gov (United States)

    Vermeulen, E; Stronks, K; Visser, M; Brouwer, I A; Snijder, M B; Mocking, R J T; Derks, E M; Schene, A H; Nicolaou, M

    2017-08-01

    To investigate the association of dietary patterns derived by reduced rank regression (RRR) with depressive symptoms in a multi-ethnic population. Cross-sectional data from the HELIUS study were used. In total, 4967 men and women (18-70 years) of Dutch, South-Asian Surinamese, African Surinamese, Turkish and Moroccan origin living in the Netherlands were included. Diet was measured using ethnic-specific food frequency questionnaires. Depressive symptoms were measured with the nine-item patient health questionnaire. By performing RRR in the whole population and per ethnic group, comparable dietary patterns were identified and therefore the dietary pattern for the whole population was used for subsequent analyses. We identified a dietary pattern that was strongly related to eicosapentaenoic acid+docosahexaenoic acid, folate, magnesium and zinc (response variables) and which was characterized by milk products, cheese, whole grains, vegetables, legumes, nuts, potatoes and red meat. After adjustment for confounders, a statistically significant inverse association was observed in the whole population (B: -0.03, 95% CI: -0.06, -0.00, P=0.046) and among Moroccan (B: -0.09, 95% CI: -0.13, -0.04, P=0.027) and South-Asian Surinamese participants (B: -0.05, 95% CI: -0.09, -0.01, P=dietary pattern and significant depressed mood in any of the ethnic groups. No consistent evidence was found that consumption of a dietary pattern, high in nutrients that are hypothesized to protect against depression, was associated with lower depressive symptoms across different ethnic groups.

  15. Microbial biosensors

    International Nuclear Information System (INIS)

    Le Yu; Chen, Wilfred; Mulchandani, Ashok

    2006-01-01

    A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

  16. Microbial conversion technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lau, P. [National Research Council of Canada, Ottawa, ON (Canada). Bioconversion and Sustainable Development

    2006-07-01

    Microbes are a biomass and an valuable resource. This presentation discussed microbial conversion technologies along with background information on microbial cells, their characteristics and microbial diversity. Untapped opportunities for microbial conversion were identified. Metagenomic and genome mining approaches were also discussed, as they can provide access to uncultivated or unculturable microorganisms in communal populations and are an unlimited resource for biocatalysts, novel genes and metabolites. Genome mining was seen as an economical approach. The presentation also emphasized that the development of microbial biorefineries would require significant insights into the relevant microorganisms and that biocatalysts were the ultimate in sustainability. In addition, the presentation discussed the natural fibres initiative for biochemicals and biomaterials. Anticipated outputs were identified and work in progress of a new enzyme-retting cocktail to provide diversity and/or consistency in fibre characteristics for various applications were also presented. It was concluded that it is necessary to leverage understanding of biological processes to produce bioproducts in a clean and sustainable manner. tabs., figs.

  17. The Effect of Long Term Mercury Pollution on the Soil Microbial Community

    DEFF Research Database (Denmark)

    Müller, A.K.; Westergaard, K.; Christensen, Søren

    2001-01-01

    The effect of long-term exposure to mercury on the soil microbial community was investigated in soil from three different sites along a pollution gradient. The amount of total and bioavailable mercury was negatively correlated to the distance from the center of contamination. The size...... of the bacterial and protozoan populations was reduced in the most contaminated soil, whereas there was no significant difference in fungal biomass measured as chitinase activity. Based on the number of colony morphotypes, moreover, the culturable bacterial population was structurally less diverse and contained...... of the number and abundance of bands. The functional potential of the microbial population measured as sole carbon source utilization by Ecoplates® differed between the soils, but there was no change in the number of substrates utilized. The observed changes in the different soil microbial populations...

  18. MICROBIAL MATS - A JOINT VENTURE

    NARCIS (Netherlands)

    VANGEMERDEN, H

    Microbial mats characteristically are dominated by a few functional groups of microbes: cyanobacteria, colorless sulfur bacteria, purple sulfur bacteria, and sulfate-reducing bacteria. Their combined metabolic activities result in steep environmental microgradients, particularly of oxygen and

  19. A new anti-microbial combination prolongs the latency period, reduces acute histologic chorioamnionitis as well as funisitis, and improves neonatal outcomes in preterm PROM.

    Science.gov (United States)

    Lee, JoonHo; Romero, Roberto; Kim, Sun Min; Chaemsaithong, Piya; Park, Chan-Wook; Park, Joong Shin; Jun, Jong Kwan; Yoon, Bo Hyun

    2016-03-01

    Antibiotic administration is a standard practice in preterm premature rupture of membranes (PROM). Specific anti-microbial agents often include ampicillin and/or erythromycin. Anaerobes and genital mycoplasmas are frequently involved in preterm PROM, but are not adequately covered by antibiotics routinely used in clinical practice. Our objective was to compare outcomes of PROM treated with standard antibiotic administration versus a new combination more effective against these bacteria. A retrospective study compared perinatal outcomes in 314 patients with PROM 23 ng/mL). (1) Patients treated with regimen 2 had a longer median antibiotic-to-delivery interval than those with regimen 1 [median (interquartile range) 23 d (10-51 d) versus 12 d (5-52 d), p acute histologic chorioamnionitis (50.5% versus 66.7%, p hemorrhage (IVH) and cerebral palsy (CP) were significantly lower in patients allocated to regimen 2 than regimen 1 (IVH: 2.1% versus 19.0%, p acute histologic chorioamnionitis/funisitis, and improved neonatal outcomes in patients with preterm PROM. These findings suggest that the combination of anti-microbial agents (ceftriaxone, clarithromycin, and metronidazole) may improve perinatal outcome in preterm PROM.

  20. Growth performance, duodenal morphology and the caecal microbial population in female broiler chickens fed glycine-fortified low protein diets under heat stress conditions.

    Science.gov (United States)

    Awad, E A; Idrus, Z; Soleimani Farjam, A; Bello, A U; Jahromi, M F

    2018-03-09

    1. This study was undertaken to examine the effect of feeding glycine (Gly)-fortified low protein (LP) diets on the growth performance, duodenal morphology and caecal microbial populations of broiler chickens raised under unheated, cyclic or constant heat stress environmental conditions. 2. From d 1 to 21 (starter phase), an equivalent number of birds were fed either a normal protein (NP) diet or a LP diet fortified with Gly. From d 22 to 42 (grower phase), an equivalent number of birds from each starter diet were distributed to one of the following dietary groups: (i) an NP diet during the starter and grower phases (NPNP), (ii) an NP diet during the starter phase and a LP diet during the grower phase (NPLP), (iii) an LP diet during the starter phase and an NP diet during the grower phase (LPNP) or (iv) LP diets during both phases (LPLP). 3. Commencing from d 22, an equivalent number of birds from each dietary group were exposed to (i) 23 ± 1°C throughout (unheated), (ii) 34 ± 1°C for 7 h each day from 10:00 to 17:00 (cyclic heat) or (iii) 34 ± 1°C throughout (constant heat). 4. Feeding the LP diet during the starter phase resulted in feed intake (FI), weight gain (WG), feed conversion ratios (FCR) and energy efficiency ratios (EER) similar to those for the NP diet. The birds fed the LP diet had a significantly higher protein efficiency ratio (PER) compared with the birds fed the NP diet. 5. During the grower phase, there were significant diet × temperature interactions for F, WG, FCR, PER, EER, villus height, crypt depth and caecal Clostridia. The birds fed the NPLP and LPLP diets had lower FI, WG and EER, higher FCR, shorter villus height and crypt depth and higher caecal Clostridia compared with the birds fed LPNP and NPNP diets under constant heat stress. However, feeding birds the NPLP and LPLP diets resulted in FI, WG, EER, FCR, morphology parameters and caecal Clostridia equivalent to the birds fed LPNP and NPNP diets, as well as improved PER

  1. Microbial activities and communities in oil sands tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Gieg, Lisa; Ramos, Esther; Clothier, Lindsay; Bordenave, Sylvain; Lin, Shiping; Voordouw, Gerrit; Dong, Xiaoli; Sensen, Christoph [University of Calgary (Canada)

    2011-07-01

    This paper discusses how the microbial communities and their activity play a vital role in tailings ponds. The ponds contain microorganisms along with metals, hydrocarbon diluent, naphthenic acid and others. The ponds play an important role in mining operations because they store bitumen extraction waste and also allow water to be re-used in the bitumen extraction process. Pond management presents a few challenges that include, among others, gas emissions and the presence of toxic and corrosive acids. Microbial activities and communities help in managing these ponds. Microbial activity measurement in active and inactive ponds is described and analyzed and the results are presented. The conditions for reducing sulfate, nitrate and iron are also presented. From the results it can be concluded that naphthenic acids can potentially serve as substrates for anaerobic populations in tailings ponds.

  2. [The Common Risk Factor Approach - An Integrated Population- and Evidence-Based Approach for Reducing Social Inequalities in Oral Health].

    Science.gov (United States)

    Heilmann, A; Sheiham, A; Watt, R G; Jordan, R A

    2016-10-01

    Worldwide, non-communicable diseases including dental caries and periodontal diseases, remain a major public health problem. Moreover, there is a social gradient in health across society that runs from the top to the bottom in a linear, stepwise fashion. Health promoting behaviours become more difficult to sustain further down the social ladder. Oral health inequalities also exist in Germany. Earlier explanations of social inequalities have mainly focused on individual lifestyle factors, ignoring the broader social determinants of health and disease. Until recently, the dominant approaches to general health promotion focused on actions to reduce specific diseases, separating oral health from general health. An alternative approach is the common risk factor approach (CRFA) where risk factors common to a number of major chronic diseases, including diseases of the mouth and teeth, are tackled. The CRFA focuses on the common underlying determinants of health to improve the overall health of populations, thereby reducing social inequalities. The main implication of the CRFA for oral health policies is to work in partnership with a range of other sectors and disciplines. Oral health issues need to be integrated with recommendations to promote general health. Improvements in oral health and a reduction in oral health inequalities are more likely by working in partnership across sectors and disciplines using strategies that focus upstream on the underlying determinants of oral diseases. © Georg Thieme Verlag KG Stuttgart · New York.

  3. Role of a unique population of lithotrophic, Fe-oxidizing bacteria in forming microbial Fe-mats at the Loihi Seamount.

    Science.gov (United States)

    Emerson, D.; Rentz, J. A.; Moyer, C. L.

    2005-12-01

    The Loihi Seamount, located 30 km SE of the island of Hawai'i, is among the most active volcanos on Earth. The summit, at a depth of 1100m, includes a 250m deep caldera (Pele's Pit) formed by an eruption in 1996. The summit, and especially Pele's Pit, are the site of extensive low to intermediate temperature (10° to 65°C) hydrothermal venting, emanating both from diffuse fissures and orifices that have substantial flow rates. The vent fluid is characterized by a low sulfide content, high CO2 concentrations and Fe(II) amounts in the 10s to 100s of μM. Associated with all vents are extensive deposits of iron oxyhydroxides that typically have 107 to 108 bacterial cells/cc associated with them. The morphology of the Fe-oxides are indicative of biological origins. We have isolated microaerophilic, obligately lithotrophic Fe-oxidizing bacteria from Loihi and describe here `Mariprofundus ferroxydans' a unique bacterium that forms a filamentous iron oxide mineral. `M. ferroxydans' is the first cultured representative of a novel division of the Proteobacteria, known previously only from clones from different hydrothermal vent sites. Molecular evidence from Loihi mats based on clone libraries and terminal restriction length polymorphism (T-RFLP) analysis of 16S rRNA genes indicate that this lineage of Fe-oxidizing organisms are common inhabitants at Loihi. We speculate that this organism and its relatives form the basis of an active microbial mat community that owe their existence to the inherent gradients of Fe(II) and O2 that exist at the Loihi vents. In a geological context this is interesting because the Loihi summit and caldera are in an O2-minima zone; O2 concentrations in the bulk seawater are around 0.5 mg/l. In effect, Loihi could serve as a proxy for the late Archaean and early Proterozoic periods when the Earth's atmosphere went from reducing to oxidizing, and it is speculated that abundant Fe(II) in the Earth's oceans served as a major sink for O2 production

  4. Microbial biotechnology and circular economy in wastewater treatment

    OpenAIRE

    Nielsen, Per Halkjær

    2017-01-01

    Summary Microbial biotechnology is essential for the development of circular economy in wastewater treatment by integrating energy production and resource recovery into the production of clean water. A comprehensive knowledge about identity, physiology, ecology, and population dynamics of process‐critical microorganisms will improve process stability, reduce CO2 footprints, optimize recovery and bioenergy production, and help finding new approaches and solutions. Examples of research needs an...

  5. Are Microbial Nanowires Responsible for Geoelectrical Changes at Hydrocarbon Contaminated Sites?

    Science.gov (United States)

    Hager, C.; Atekwana, E. A.; Gorby, Y. A.; Duris, J. W.; Allen, J. P.; Atekwana, E. A.; Ownby, C.; Rossbach, S.

    2007-05-01

    Significant advances in near-surface geophysics and biogeophysics in particular, have clearly established a link between geoelectrical response and the growth and enzymatic activities of microbes in geologic media. Recent studies from hydrocarbon contaminated sites suggest that the activities of distinct microbial populations, specifically syntrophic, sulfate reducing, and dissimilatory iron reducing microbial populations are a contributing factor to elevated sediment conductivity. However, a fundamental mechanistic understanding of the processes and sources resulting in the measured electrical response remains uncertain. The recent discovery of bacterial nanowires and their electron transport capabilities suggest that if bacterial nanowires permeate the subsurface, they may in part be responsible for the anomalous conductivity response. In this study we investigated the microbial population structure, the presence of nanowires, and microbial-induced alterations of a hydrocarbon contaminated environment and relate them to the sediments' geoelectrical response. Our results show that microbial communities varied substantially along the vertical gradient and at depths where hydrocarbons saturated the sediments, ribosomal intergenic spacer analysis (RISA) revealed signatures of microbial communities adapted to hydrocarbon impact. In contrast, RISA profiles from a background location showed little community variations with depth. While all sites showed evidence of microbial activity, a scanning electron microscope (SEM) study of sediment from the contaminated location showed pervasive development of "nanowire-like structures" with morphologies consistent with nanowires from laboratory experiments. SEM analysis suggests extensive alteration of the sediments by microbial Activity. We conclude that, excess organic carbon (electron donor) but limited electron acceptors in these environments cause microorganisms to produce nanowires to shuttle the electrons as they seek for

  6. Artificial soil microcosms: a tool for studying microbial autecology under controlled conditions.

    Science.gov (United States)

    Ellis, Richard J

    2004-02-01

    A novel artificial microcosm containing all the essential chemical components of soil, but with reduced heterogeneity and biological complexity, has been developed. Its utility for supporting realistic microbial populations was demonstrated and an example of how competing bacteria can be studied is illustrated.

  7. The electric picnic: synergistic requirements for exoelectrogenic microbial communities

    KAUST Repository

    Kiely, Patrick D; Regan, John M; Logan, Bruce E

    2011-01-01

    (BESs). Analysis of the community profiles of exoelectrogenic microbial consortia in BESs fed different substrates gives a clearer picture of the different microbial populations present in these exoelectrogenic biofilms. Rapid utilization of fermentation

  8. A take-home placebo treatment can reduce stress, anxiety and symptoms of depression in a non-patient population.

    Science.gov (United States)

    Darragh, Margot; Yow, Boris; Kieser, Anel; Booth, Roger J; Kydd, Robert R; Consedine, Nathan S

    2016-09-01

    With a healthcare system burdened by symptomatic and mental-health related conditions, the placebo effect may represent a useful clinical tool. First, however, there is a need to broaden research attention and investigate placebo effects outside laboratories and beyond experimental pain. This study investigated the effectiveness of a take-home placebo treatment in the short-term alleviation of stress, anxiety and symptoms of depression in a non-patient population. A sample of 77 participants was randomized to either the 'oxytocin' treatment group (n = 22), the 'serotonin' treatment group (n = 22) or the wait-list control group (n = 33). The two treatment groups were given an 'anti-stress treatment spray' (placebo) to self-administer for 3 days, and completed online measures of perceived stress (Perceived Stress Scale-10), anxiety (Cognitive Somatic Anxiety Questionnaire) and symptoms of depression (Centre for Epidemiological Studies - Depression) before and after the 3-day protocol. Both the 'serotonin' and 'oxytocin' treatment sprays were effective in reducing symptoms of depression; however, only those in the 'oxytocin' group reported less stress and anxiety as compared with controls. Overall, the 'oxytocin' was perceived as more effective. Placebo effects can be translated to a real-life setting in the short-term reduction of stress, anxiety and symptoms of depression in a non-patient population. In treating psychological distress, placebos may be useful addition to the treatment repertoire. The information given with treatment may also be an important consideration for practitioners. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  9. The association of statin use with reduced incidence of venous thromboembolism: a population-based cohort study.

    Science.gov (United States)

    Lassila, Riitta; Jula, Antti; Pitkäniemi, Janne; Haukka, Jari

    2014-11-05

    Venous thromboembolism (VTE) continues to be a frequent medical emergency requiring rapid recognition so as to reach diagnosis and initiate anticoagulation therapy. The use of statins in addition to reducing the incidence of arterial thrombosis for decreasing the incidence and reoccurrence of VTE is reported. The aim of our study was to explore the association between statin usage and the incidence of new VTE at the population level during a 10-year follow-up. Population-based historic cohort. The Health 2000 Survey was based on a nationally representative sample. 8028 individuals aged 30 years or over in Finland. The primary end point event was the first ever hospitalisation due to one of the following causes: pulmonary embolism (International Classification of Diseases-10 I26), cerebral venous non-pyogenic thrombosis (I63.6), or venous thrombosis (I80.9-189). The preselected explanatory variables applied to the Poisson regression model were statin usage (no/yes) during follow-up (2000-2011) and several baseline data (age, sex; usage of blood glucose lowering drugs, vitamin K antagonists and antiplatelet agents). We observed 136 VTE events, the incidence of 1.72 (95% CI 1.44 to 2.04) per 1000 person-years. Current statin usage did not associate with the incidence of VTE according to the univariate model (rate ratio (RR) 0.93, 0.56 to 1.52), but when adjusted with baseline variables (age, sex, medications) the RR declined to 0.60 (0.36 to 1.00, p=0.04). Statin use offers protection against first ever VTE events and appears as a primary prevention tool in patients without anticoagulation or antiplatelet medication. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  10. Deletion Genotypes Reduce Occlusion Body Potency but Increase Occlusion Body Production in a Colombian Spodoptera frugiperda Nucleopolyhedrovirus Population

    Science.gov (United States)

    Barrera, Gloria; Williams, Trevor; Villamizar, Laura; Caballero, Primitivo; Simón, Oihane

    2013-01-01

    A Colombian field isolate (SfCOL-wt) of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is a mixture of different genotypes. To evaluate the insecticidal properties of the different genotypic variants, 83 plaque purified virus were characterized. Ten distinct genotypes were identified (named A through J). SfCOL-A was the most prevalent (71±2%; mean ± SE) showing a PstI restriction profile indistinguishable to that of SfCOL-wt. The remaining nine genotypes presented genomic deletions of 3.8 - 21.8 Kb located mainly between nucleotides 11,436 and 33,883 in the reference genome SfMNPV-B, affecting the region between open reading frames (ORFs) sf20 and sf33. The insecticidal activity of each genotype from SfCOL-wt and several mixtures of genotypes was compared to that of SfCOL-wt. The potency of SfCOL-A occlusion bodies (OBs) was 4.4-fold higher than SfCOL-wt OBs, whereas the speed of kill of SfCOL-A was similar to that of SfCOL-wt. Deletion genotype OBs were similarly or less potent than SfCOL-wt but six deletion genotypes were faster killing than SfCOL-wt. The potency of genotype mixtures co-occluded within OBs were consistently reduced in two-genotype mixtures involving equal proportions of SfCOL-A and one of three deletion genotypes (SfCOL-C, -D or -F). Speed of kill and OB production were improved only when the certain genotype mixtures were co-occluded, although OB production was higher in the SfCOL-wt isolate than in any of the component genotypes, or mixtures thereof. Deleted genotypes reduced OB potency but increased OB production of the SfCOL-wt population, which is structured to maximize the production of OBs in each infected host. PMID:24116220

  11. Deletion genotypes reduce occlusion body potency but increase occlusion body production in a Colombian Spodoptera frugiperda nucleopolyhedrovirus population.

    Directory of Open Access Journals (Sweden)

    Gloria Barrera

    Full Text Available A Colombian field isolate (SfCOL-wt of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV is a mixture of different genotypes. To evaluate the insecticidal properties of the different genotypic variants, 83 plaque purified virus were characterized. Ten distinct genotypes were identified (named A through J. SfCOL-A was the most prevalent (71±2%; mean ± SE showing a PstI restriction profile indistinguishable to that of SfCOL-wt. The remaining nine genotypes presented genomic deletions of 3.8 - 21.8 Kb located mainly between nucleotides 11,436 and 33,883 in the reference genome SfMNPV-B, affecting the region between open reading frames (ORFs sf20 and sf33. The insecticidal activity of each genotype from SfCOL-wt and several mixtures of genotypes was compared to that of SfCOL-wt. The potency of SfCOL-A occlusion bodies (OBs was 4.4-fold higher than SfCOL-wt OBs, whereas the speed of kill of SfCOL-A was similar to that of SfCOL-wt. Deletion genotype OBs were similarly or less potent than SfCOL-wt but six deletion genotypes were faster killing than SfCOL-wt. The potency of genotype mixtures co-occluded within OBs were consistently reduced in two-genotype mixtures involving equal proportions of SfCOL-A and one of three deletion genotypes (SfCOL-C, -D or -F. Speed of kill and OB production were improved only when the certain genotype mixtures were co-occluded, although OB production was higher in the SfCOL-wt isolate than in any of the component genotypes, or mixtures thereof. Deleted genotypes reduced OB potency but increased OB production of the SfCOL-wt population, which is structured to maximize the production of OBs in each infected host.

  12. Microbial glycoproteomics

    DEFF Research Database (Denmark)

    Halim, Adnan; Anonsen, Jan Haug

    2017-01-01

    Mass spectrometry-based "-omics" technologies are important tools for global and detailed mapping of post-translational modifications. Protein glycosylation is an abundant and important post translational modification widespread throughout all domains of life. Characterization of glycoproteins...... and research in this area is rapidly accelerating. Here, we review recent developments in glycoproteomic technologies with a special focus on microbial protein glycosylation....

  13. Effect of dietary supplementation with Rhizopus oryzae or Chrysonilia crassa on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

    Directory of Open Access Journals (Sweden)

    S. Sugiharto

    2017-09-01

    Full Text Available Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from the ileum of indigenous Indonesian chickens which exhibited probiotic and antioxidant properties. Two hundred and forty 21-day-old male broiler chicks were randomly allotted into six groups, including birds reared under normal temperature (28 ± 2 °C (CONT, birds reared under HS conditions (35 ± 2 °C (HS-CONT, birds reared under HS and provided with commercial anti-stress formula (HS-VIT, birds reared under HS and provided with R. oryzae (HS-RO, birds reared under HS and provided with C. crassa (HS-CC and birds reared under HS and provided with rice bran (HS-RB. Body weight gain was highest (P < 0. 01 and lowest (P < 0. 01 in CONT and HS-CONT birds, respectively. The heart was heavier (P < 0. 05 in CONT than in HS-CONT and HS-VIT birds. CONT birds had heavier duodenum (P < 0. 05 and jejunum (P < 0. 01 than other birds. Eosinophils was higher (P < 0. 05 in HS-CC than in other birds. Low-density lipoprotein (LDL was higher (P < 0. 05 in HS-CONT than in CONT, HS-VIT and HS-CC birds. Total triglyceride was highest (P < 0. 05 and lowest (P < 0. 05 in HS-RB and HS-RO birds, respectively. Alanine aminotransferase (ALT was higher (P < 0. 05 in HS-CONT than in other HS birds. Total protein was lowest and highest (P < 0. 05 in CONT and HS-CONT birds, respectively. Albumin was higher (P < 0. 05 in HS-CONT and HS-VIT than in HS-RO birds. Globulin was lower (P < 0. 05 in CONT than in HS

  14. Oral administration of Saccharomyces boulardii ameliorates carbon tetrachloride-induced liver fibrosis in rats via reducing intestinal permeability and modulating gut microbial composition.

    Science.gov (United States)

    Li, Ming; Zhu, Lin; Xie, Ao; Yuan, Jieli

    2015-02-01

    To investigate the effects of orally administrated Saccharomyces boulardii (S. boulardii) on the progress of carbon tetrachloride (CCl4)-induced liver fibrosis, 34 male Wistar rats were randomly divided into four experimental groups including the control group (n = 8), the cirrhotic group (n = 10), the preventive group (n = 8), and the treatment group (n = 8). Results showed that the liver expression levels of collagen, type I, alpha 1 (Col1A1), alpha smooth muscle actin (αSMA), transforming growth factor beta (TGF-β) and the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA) increased significantly in cirrhotic rats compared with control and decreased by S. boulardii administration. Treatment of S. boulardii also attenuated the increased endotoxin levels and pro-inflammatory cytokines in CCl4-treated rats. And, these were associated with the changes of intestinal permeability and fecal microbial composition. Our study suggested that oral administration of S. boulardii can promote the liver function of CCl4-treated rats, and the preventive treatment of this probiotic yeast may decelerate the progress of liver fibrosis.

  15. Reduced dietary sodium intake increases heart rate. A meta-analysis of 63 randomized controlled trials including 72 study populations.

    Directory of Open Access Journals (Sweden)

    Niels eGraudal

    2016-03-01

    Full Text Available Reduced dietary sodium intake (sodium reduction increases heart rate in some studies of animals and humans. As heart rate is independently associated with the development of heart failure and increased risk of premature death a potential increase in heart rate could be a harmful side-effect of sodium reduction. The purpose of the present meta-analysis was to investigate the effect of sodium reduction on heart rate. Relevant studies were retrieved from an updated pool of 176 randomized controlled trials (RCTs published in the period 1973–2014. 63 of the RCTs including 72 study populations reported data on heart rate. In a meta-analysis of these data sodium reduction increased heart rate with 1.65 beats per minute [95% CI: 1.19, 2.11], p < 0.00001, corresponding to 2.4% of the baseline heart rate. This effect was independent of baseline blood pressure. In conclusion sodium reduction increases heart rate by as much (2.4% as it decreases blood pressure (2.5%. This side-effect, which may cause harmful health effects, contributes to the need for a revision of the present dietary guidelines.

  16. Process Evaluation and Costing of a Multifaceted Population-Wide Intervention to Reduce Salt Consumption in Fiji.

    Science.gov (United States)

    Webster, Jacqui; Pillay, Arti; Suku, Arleen; Gohil, Paayal; Santos, Joseph Alvin; Schultz, Jimaima; Wate, Jillian; Trieu, Kathy; Hope, Silvia; Snowdon, Wendy; Moodie, Marj; Jan, Stephen; Bell, Colin

    2018-01-30

    This paper reports the process evaluation and costing of a national salt reduction intervention in Fiji. The population-wide intervention included engaging food industry to reduce salt in foods, strategic health communication and a hospital program. The evaluation showed a 1.4 g/day drop in salt intake from the 11.7 g/day at baseline; however, this was not statistically significant. To better understand intervention implementation, we collated data to assess intervention fidelity, reach, context and costs. Government and management changes affected intervention implementation, meaning fidelity was relatively low. There was no active mechanism for ensuring food companies adhered to the voluntary salt reduction targets. Communication activities had wide reach but most activities were one-off, meaning the overall dose was low and impact on behavior limited. Intervention costs were moderate (FJD $277,410 or $0.31 per person) but the strategy relied on multi-sector action which was not fully operationalised. The cyclone also delayed monitoring and likely impacted the results. However, 73% of people surveyed had heard about the campaign and salt reduction policies have been mainstreamed into government programs. Longer-term monitoring of salt intake is planned through future surveys and lessons from this process evaluation will be used to inform future strategies in the Pacific Islands and globally.

  17. A Dietary Pattern Derived by Reduced Rank Regression is Associated with Type 2 Diabetes in An Urban Ghanaian Population

    Directory of Open Access Journals (Sweden)

    Laura K. Frank

    2015-07-01

    Full Text Available Reduced rank regression (RRR is an innovative technique to establish dietary patterns related to biochemical risk factors for type 2 diabetes, but has not been applied in sub-Saharan Africa. In a hospital-based case-control study for type 2 diabetes in Kumasi (diabetes cases, 538; controls, 668 dietary intake was assessed by a specific food frequency questionnaire. After random split of our study population, we derived a dietary pattern in the training set using RRR with adiponectin, HDL-cholesterol and triglycerides as responses and 35 food items as predictors. This pattern score was applied to the validation set, and its association with type 2 diabetes was examined by logistic regression. The dietary pattern was characterized by a high consumption of plantain, cassava, and garden egg, and a low intake of rice, juice, vegetable oil, eggs, chocolate drink, sweets, and red meat; the score correlated positively with serum triglycerides and negatively with adiponectin. The multivariate-adjusted odds ratio of type 2 diabetes for the highest quintile compared to the lowest was 4.43 (95% confidence interval: 1.87–10.50, p for trend < 0.001. The identified dietary pattern increases the odds of type 2 diabetes in urban Ghanaians, which is mainly attributed to increased serum triglycerides.

  18. Process Evaluation and Costing of a Multifaceted Population-Wide Intervention to Reduce Salt Consumption in Fiji

    Directory of Open Access Journals (Sweden)

    Jacqui Webster

    2018-01-01

    Full Text Available This paper reports the process evaluation and costing of a national salt reduction intervention in Fiji. The population-wide intervention included engaging food industry to reduce salt in foods, strategic health communication and a hospital program. The evaluation showed a 1.4 g/day drop in salt intake from the 11.7 g/day at baseline; however, this was not statistically significant. To better understand intervention implementation, we collated data to assess intervention fidelity, reach, context and costs. Government and management changes affected intervention implementation, meaning fidelity was relatively low. There was no active mechanism for ensuring food companies adhered to the voluntary salt reduction targets. Communication activities had wide reach but most activities were one-off, meaning the overall dose was low and impact on behavior limited. Intervention costs were moderate (FJD $277,410 or $0.31 per person but the strategy relied on multi-sector action which was not fully operationalised. The cyclone also delayed monitoring and likely impacted the results. However, 73% of people surveyed had heard about the campaign and salt reduction policies have been mainstreamed into government programs. Longer-term monitoring of salt intake is planned through future surveys and lessons from this process evaluation will be used to inform future strategies in the Pacific Islands and globally.

  19. Outdoor air pollution as a possible modifiable risk factor to reduce mortality in post-stroke population

    Directory of Open Access Journals (Sweden)

    Anita Desikan

    2017-01-01

    Full Text Available Outdoor air pollution is a known risk factor for mortality and morbidity. The type of air pollutant most reliably associated with disease is particulate matter (PM, especially finer particulate matter that can reach deeper into the lungs like PM2.5 (particulate matter diameter < 2.5 μm. Some subpopulations may be particularly vulnerable to PM pollution. This review focuses on one subgroup, long-term stroke survivors, and the emerging evidence suggesting that survivors of a stroke may be at a higher risk from the deleterious effects of PM pollution. While the mechanisms for mortality are still under debate, long-term stroke survivors may be vulnerable to similar mechanisms that underlie the well-established association between PM pollution and cardiovascular disease. The fact that long-term stroke survivors of ischemic, but not hemorrhagic, strokes appear to be more vulnerable to the risk of death from higher PM pollution may also bolster the connection to ischemic heart disease. Survivors of an ischemic stroke may be more vulnerable to dying from higher concentrations of PM pollution than the general population. The clinical implications of this association suggest that reduced exposure to PM pollution may result in fewer deaths amongst stroke survivors.

  20. Microbial biosensors for environmental monitoring

    Directory of Open Access Journals (Sweden)

    David VOGRINC

    2015-12-01

    Full Text Available Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.

  1. Acid-reducing vagotomy is associated with reduced risk of subsequent ischemic heart disease in complicated peptic ulcer: An Asian population study.

    Science.gov (United States)

    Wu, Shih-Chi; Fang, Chu-Wen; Chen, William Tzu-Liang; Muo, Chih-Hsin

    2016-12-01

    Persistent exacerbation of a peptic ulcer may lead to a complicated peptic ulcer (perforation or/and bleeding). The management of complicated peptic ulcers has shifted from acid-reducing vagotomy, drainage, and gastrectomy to simple local suture or non-operative (endoscopic/angiographic) hemostasis. We were interested in the long-term effects of this trend change. In this study, complicated peptic ulcer patients who received acid-reducing vagotomy were compared with those who received simple suture/hemostasis to determine the risk of ischemic heart disease (IHD).This retrospective cohort study analyzed 335,680 peptic ulcer patients recorded from 2000 to 2006 versus 335,680 age-, sex-, comorbidity-, and index-year matched comparisons. Patients with Helicobacter pylori (HP) infection were excluded. In order to identify the effect of vagus nerve severance, patients who received gastrectomy or antrectomy were also excluded. The incidence of IHD in both cohorts, and in the complicated peptic ulcer patients who received acid-reducing vagotomy versus those who received simple suture or hemostasis was evaluated.The overall incidence of IHD was higher in patients with peptic ulcer than those without peptic ulcer (17.00 vs 12.06 per 1000 person-years), with an adjusted hazard ratio (aHR) of 1.46 based on multivariable Cox proportional hazards regression analysis controlling for age, sex, Charlson's comorbidity index, and death (competing risk). While comparing peptic ulcer patients with acid-reducing vagotomy to those with simple suture/hemostasis or those without surgical treatment, the aHR (0.58) was the lowest in the acid-reducing vagotomy group.Patients with peptic ulcer have an elevated risk of IHD. However, complicated peptic ulcer patients who received acid-reducing vagotomy were associated with reduced risk of developing IHD.

  2. Reconsidering rumen microbial consortia to enhance feed efficiency and reduce environmental impact of ruminant livestock production systems Consórcios microbianos no rúmen para melhorar a eficiência alimentar e reduzir o impacto ambiental dos sistemas de produção animal

    Directory of Open Access Journals (Sweden)

    Jeffrey Lynn Firkins

    2010-07-01

    Full Text Available Because cultivation-based approaches to assess rumen microbiology assess only the minority of microbial groups and can miss opportunities to assess important functions, molecular-based approaches have flourished in microbial ecology and have been adapted to the rumen. Current approaches are described herein, specifically for a robust adaptation to nutrition studies or future opportunities. These included automated profiling techniques, density gradient gel electrophoresis, and future adaption of microarray or high-throughput sequencing technologies. Based on current knowledge, a more holistic approach is needed to describe various functional groups of microbes within the context of how they influence, and are influenced by, the whole consortium (combination of microbial groups. Such a perspective is applied to issues related to increasing fiber digestibility when feeding concentrate or unsaturated fats to high producing beef and dairy cattle. These same microbial populations should help to provide growth factors for fibrolytic bacteria while competing against the hyperammonia-producing bacteria such that there would be less need for excessive rumen-degraded protein as a safety factor. Moreover, these same dietary conditions influence the processes of biohydrogenation and methanogenesis. After accounting for population structures of bacteria, protozoa, methanogenic archaea, and even fungi, efforts to integrate molecular-based rumen microbial ecology with dietary conditions should allow us to better explain and therefore predict conditions that will improve feed efficiency and reduce environmental impact of ruminant production systems.Técnicas tradicionais de identificação de microorganismos ruminais utilizando metodologias de cultivo conseguem identificar um pequeno grupo de bactérias. Técnicas de identificação molecular têm sido amplamente utilizadas em ecossistemas microbiológicos e adaptadas em estudos com ruminantes. Fundamentado no

  3. Improvement of Carbon Dioxide Sweep Efficiency by Utilization of Microbial Permeability Profile Modification to Reduce the Amount of Oil Bypassed During Carbon Dioxide Flood

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Darrel [Mississippi State Univ., Mississippi State, MS (United States); Brown, Lewis [Mississippi State Univ., Mississippi State, MS (United States); Lynch, F. Leo [Mississippi State Univ., Mississippi State, MS (United States); Kirkland, Brenda L. [Mississippi State Univ., Mississippi State, MS (United States); Collins, Krystal M. [Mississippi State Univ., Mississippi State, MS (United States); Funderburk, William K. [Mississippi State Univ., Mississippi State, MS (United States)

    2010-12-31

    The objective of this project was to couple microbial permeability profile modification (MPPM), with carbon dioxide flooding to improve oil recovery from the Upper Cretaceous Little Creek Oil Field situated in Lincoln and Pike counties, MS. This study determined that MPPM technology, which improves production by utilizing environmentally friendly nutrient solutions to simulate the growth of the indigenous microflora in the most permeable zones of the reservoir thus diverting production to less permeable, previously unswept zones, increased oil production without interfering with the carbon dioxide flooding operation. Laboratory tests determined that no microorganisms were produced in formation waters, but were present in cores. Perhaps the single most significant contribution of this study is the demonstration that microorganisms are active at a formation temperature of 115°C (239°F) by using a specially designed culturing device. Laboratory tests were employed to simulate the MPPM process by demonstrating that microorganisms could be activated with the resulting production of oil in coreflood tests performed in the presence of carbon dioxide at 66°C (the highest temperature that could be employed in the coreflood facility). Geological assessment determined significant heterogeneity in the Eutaw Formation, and documented relatively thin, variably-lithified, well-laminated sandstone interbedded with heavily-bioturbated, clay-rich sandstone and shale. Live core samples of the Upper Cretaceous Eutaw Formation from the Heidelberg Field, MS were quantitatively assessed using SEM, and showed that during MPPM permeability modification occurs ubiquitously within pore and throat spaces of 10-20 μm diameter. Testing of the MPPM procedure in the Little Creek Field showed a significant increase in production occurred in two of the five production test wells; furthermore, the decline curve in each of the production wells became noticeably less steep. This project greatly

  4. Advanced Microscopy of Microbial Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    Growing awareness of heterogeneity in cells of microbial populations has emphasized the importance of advanced microscopy for visualization and understanding of the molecular mechanisms underlying cell-to-cell variation. In this review, we highlight some of the recent advances in confocal...... microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  5. Attempts to reduce alcohol intake and treatment needs among people with probable alcohol dependence in England: a general population survey.

    Science.gov (United States)

    Dunne, Jacklyn; Kimergård, Andreas; Brown, Jamie; Beard, Emma; Buykx, Penny; Michie, Susan; Drummond, Colin

    2018-03-25

    To compare the proportion of people in England with probable alcohol dependence [Alcohol Use Disorders Identification Test (AUDIT) score ≥ 20] with those with other drinking patterns (categorized by AUDIT scores) in terms of motivation to reduce drinking and use of alcohol support resources. A combination of random probability and simple quota sampling to conduct monthly cross-sectional household computer-assisted interviews between March 2014 and August 2017. The general population in all nine regions of England. Participants in the Alcohol Toolkit Study (ATS), a monthly household survey of alcohol consumption among people aged 16 years and over in England (n = 69 826). The mean age was 47 years [standard deviation (SD) = 18.78; 95% confidence interval (CI) = 46.8-47] and 51% (n = 35 560) were female. χ 2 tests were used to investigate associations with demographic variables, motivation to quit drinking, attempts to quit drinking, general practitioner (GP) engagement and types of support accessed in the last 12 months across AUDIT risk zones. A total of 0.6% were classified as people with probable alcohol dependence (95% CI = 0.5-0.7). Motivation to quit (χ 2  = 1692.27, P AUDIT risk zone. People with probable dependence were more likely than other ATS participants to have a past-year attempt to cut down or quit (51.8%) and have received a specialist referral from their GP about drinking (13.7%), and less likely to report no motivation to reduce their drinking (26.2%). Those with probable dependence had higher use of self-help books and mobile applications (apps) than other ATS participants; however, 27.7% did not access any resources during their most recent attempt to cut down. Adults in England with probable alcohol dependence, measured through the Alcohol Use Disorders Identification Test, demonstrate higher motivation to quit drinking and greater use of both specialist treatment and self-driven support compared with those in other

  6. Microbial xanthophylls.

    Science.gov (United States)

    Bhosale, Prakash; Bernstein, Paul S

    2005-09-01

    Xanthophylls are oxygenated carotenoids abundant in the human food supply. Lutein, zeaxanthin, and cryptoxanthin are major xanthophyll carotenoids in human plasma. The consumption of these xanthophylls is directly associated with reduction in the risk of cancers, cardiovascular disease, age-related macular degeneration, and cataract formation. Canthaxanthin and astaxanthin also have considerable importance in aquaculture for salmonid and crustacean pigmentation, and are of commercial interest for the pharmaceutical and food industries. Chemical synthesis is a major source for the heavy demand of xanthophylls in the consumer market; however, microbial producers also have potential as commercial sources. In this review, we discuss the biosynthesis, commercial utility, and major microbial sources of xanthophylls. We also present a critical review of current research and technologies involved in promoting microbes as potential commercial sources for mass production.

  7. General anesthesia exposure in early life reduces the risk of allergic diseases: A nationwide population-based cohort study.

    Science.gov (United States)

    Kuo, Ho-Chang; Yang, Ya-Ling; Ho, Shu-Chen; Guo, Mindy Ming-Huey; Jiang, Jyun-Hong; Huang, Ying-Hsien

    2016-07-01

    General anesthesia (GA) has been used for second line treatment strategy for status asthmaticus in pediatric patients. The association between GA in children and risk of followed-up allergic diseases is unclear. This study aims to assess the risk of allergic diseases after GA in children.We did a nationwide retrospective cohort study by analyzing data from the National Health Insurance Research Database (NHIRD) in Taiwan. The subsequent risks for allergic diseases, including asthma (ICD-9: 493.X), allergic rhinitis (AR; ICD-9 CM code 477.X), and atopic dermatitis (AD; ICD-9-CM code 691.X), were compared between exposure to GA and none before 1 year of age throughout the follow-up period using the Cox proportional hazards model.Insurance claims data for 32,742 children younger than 1 year old from all insured children in the NHIRD. Of those, 2358 subjects were exposed to GA; 414 and 1944 children exposed to mask and intubation ventilation, respectively, served as the study cohort, whereas the remaining 30,384 children made up the comparison cohort. Children in the GA group were at a lower risk of developing asthma, AR and AD, with adjusted hazard ratios of 0.67 (0.62-0.72, 95%CI), 0.72 (0.68-0.77, 95%CI), 0.60 (0.56-0.64, 95%CI), respectively.Children who were exposed to GA in early life before 1 year of age had reduced risk of subsequently developing allergic diseases such as asthma, AD, and AR, when compared with general population.

  8. Microbial Biotechnology 2020; microbiology of fossil fuel resources.

    Science.gov (United States)

    Head, Ian M; Gray, Neil D

    2016-09-01

    This roadmap examines the future of microbiology research and technology in fossil fuel energy recovery. Globally, the human population will be reliant on fossil fuels for energy and chemical feedstocks for at least the medium term. Microbiology is already important in many areas relevant to both upstream and downstream activities in the oil industry. However, the discipline has struggled for recognition in a world dominated by geophysicists and engineers despite widely known but still poorly understood microbially mediated processes e.g. reservoir biodegradation, reservoir souring and control, microbial enhanced oil recovery. The role of microbiology is even less understood in developing industries such as shale gas recovery by fracking or carbon capture by geological storage. In the future, innovative biotechnologies may offer new routes to reduced emissions pathways especially when applied to the vast unconventional heavy oil resources formed, paradoxically, from microbial activities in the geological past. However, despite this potential, recent low oil prices may make industry funding hard to come by and recruitment of microbiologists by the oil and gas industry may not be a high priority. With regards to public funded research and the imperative for cheap secure energy for economic growth in a growing world population, there are signs of inherent conflicts between policies aimed at a low carbon future using renewable technologies and policies which encourage technologies which maximize recovery from our conventional and unconventional fossil fuel assets. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  9. Influence of sire breed on the interplay among rumen microbial populations inhabiting the rumen liquid of the progeny in beef cattle.

    Directory of Open Access Journals (Sweden)

    Emma Hernandez-Sanabria

    Full Text Available This study aimed to evaluate whether the host genetic background impact the ruminal microbial communities of the progeny of sires from three different breeds under different diets. Eighty five bacterial and twenty eight methanogen phylotypes from 49 individuals of diverging sire breed (Angus, ANG; Charolais, CHA; and Hybrid, HYB, fed high energy density (HE and low energy density (LE diets were determined and correlated with breed, rumen fermentation and phenotypic variables, using multivariate statistical approaches. When bacterial phylotypes were compared between diets, ANG offspring showed the lowest number of diet-associated phylotypes, whereas CHA and HYB progenies had seventeen and twenty-three diet-associated phylotypes, respectively. For the methanogen phylotypes, there were no sire breed-associated phylotypes; however, seven phylotypes were significantly different among breeds on either diet (P<0.05. Sire breed did not influence the metabolic variables measured when high energy diet was fed. A correlation matrix of all pairwise comparisons among frequencies of bacterial and methanogen phylotypes uncovered their relationships with sire breed. A cluster containing methanogen phylotypes M16 (Methanobrevibacter gottschalkii and M20 (Methanobrevibacter smithii, and bacterial phylotype B62 (Robinsoniella sp. in Angus offspring fed low energy diet reflected the metabolic interactions among microbial consortia. The clustering of the phylotype frequencies from the three breeds indicated that phylotypes detected in CHA and HYB progenies are more similar among them, compared to ANG animals. Our results revealed that the frequency of particular microbial phylotypes in the progeny of cattle may be influenced by the sire breed when different diets are fed and ultimately further impact host metabolic functions, such as feed efficiency.

  10. Influence of diet and microbial activity in the digestive tract on digestibility, and nitrogen and energy metabolism in rats and pigs

    DEFF Research Database (Denmark)

    Eggum, B O; Thorbek, G; Beames, R M

    1982-01-01

    -55 kg. Measurements were made on the influence of microbial activity in the digestive tract on digestibility and nitrogen and energy metabolism. Dietary inclusion of the antibiotic Nebacitin was the method used to reduce the microbial population. 2. The microbial activity in the hind-gut (mumol ATP....../g air-dry contents) of antibiotic-treated rats was reduced to approximately one-tenth of that of untreated rats. 3. Live-weight gain was not significantly affected in either species by a reduction in the microbial activity, in spite of a reduction in dry matter digestibility in animals with reduced...... microflora. 4. For rats on low-crude-fibre diets, a reduction in microflora reduced digestibility of all nutrients and energy and metabolizability of digestible energy by approximately 5.4%. All differences were highly significant. On high-crude-fibre diets the decrease was approximately 5.9%. In pigs...

  11. The Microbial Database for Danish wastewater treatment plants with nutrient removal (MiDas-DK) – a tool for understanding activated sludge population dynamics and community stability

    DEFF Research Database (Denmark)

    Mielczarek, Artur Tomasz; Saunders, Aaron Marc; Larsen, Poul

    2013-01-01

    Since 2006 more than 50 Danish full-scale wastewater treatment plants with nutrient removal have been investigated in a project called ‘The Microbial Database for Danish Activated Sludge Wastewater Treatment Plants with Nutrient Removal (MiDas-DK)’. Comprehensive sets of samples have been collected......, analyzed and associated with extensive operational data from the plants. The community composition was analyzed by quantitative fluorescence in situ hybridization (FISH) supported by 16S rRNA amplicon sequencing and deep metagenomics. MiDas-DK has been a powerful tool to study the complex activated sludge...

  12. Microbial O2 consumption in the Aespoe tunnel

    International Nuclear Information System (INIS)

    Kotelnikova, S.; Pedersen, Karsten

    1998-04-01

    The report presents data on microbial O 2 reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O 2 intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O 2 reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O 2 reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O 2 reduction confirming the biogenic nature of the reduction. The populations developed O 2 reduction rates and capacity depending on the initial concentration of dissolved O 2 reduction. Rates of O 2 reduction ranged from 0.32 to 4.5 μM/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 μM of dissolved O 2 ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O 2 both at 30 deg C and 60 deg C. At 16 deg C no delay in O 2 consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O 2 . Some bacteria use Hg or CH 4 as electron donor instead of organic matter, which means that microbial O 2 reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH 4 oxidation rates ranged between 3.00 and 220 nM CH 4 per litre per day. Comparison of the total O 2 reducing activities by gas chromatography and

  13. Microbial O{sub 2} consumption in the Aespoe tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Kotelnikova, S.; Pedersen, Karsten [Goeteborg Univ. (Sweden). Dept. of Cell and Molecular Biology, Microbiology

    1998-04-01

    day. Comparison of the total O{sub 2} reducing activities by gas chromatography and radiotracer tests showed that CH{sub 4} oxidation was responsible for 6.7% of the total O{sub 2} reduction in the groundwater, for 9.1 % of the total O{sub 2} reduction on stones and 57% of total O{sub 2} reduction in pond water. Most probable numbering showed that CH{sub 4} oxidation organisms constituted 0.15% and 35% of the total cell population in the groundwater and pond water, respectively. Methane oxidation is proposed as one of the dominating microbial mechanisms for O{sub 2} reduction. The contribution of hydrogen and organic carbon depending organisms remains to be studied. A kinetic model for microbial O{sub 2} has been developed, and it may be applied to performance assessment calculations of nuclear waste repositories.

  14. What is microbial community ecology?

    Science.gov (United States)

    Konopka, Allan

    2009-11-01

    The activities of complex communities of microbes affect biogeochemical transformations in natural, managed and engineered ecosystems. Meaningfully defining what constitutes a community of interacting microbial populations is not trivial, but is important for rigorous progress in the field. Important elements of research in microbial community ecology include the analysis of functional pathways for nutrient resource and energy flows, mechanistic understanding of interactions between microbial populations and their environment, and the emergent properties of the complex community. Some emergent properties mirror those analyzed by community ecologists who study plants and animals: biological diversity, functional redundancy and system stability. However, because microbes possess mechanisms for the horizontal transfer of genetic information, the metagenome may also be considered as a community property.

  15. Microbial content of abattoir wastewater and its contaminated soil in ...

    African Journals Online (AJOL)

    Microbial content of wastewater in two abattoirs and the impact on microbial population of receiving soil was studied in Agege and Ojo Local Government Areas in Lagos State, Nigeria. Wastewater samples were collected from each of the abattoirs over three months period and examined for microbial content. Soil samples ...

  16. Soil microbial community response to land use and various soil ...

    African Journals Online (AJOL)

    Soil microbial community response to land use and various soil elements in a city landscape of north China. ... African Journal of Biotechnology ... Legumes played an important role in stimulating the growth and reproduction of various soil microbial populations, accordingly promoting the microbial catabolic activity.

  17. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

    The long term safety and integrity of radioactive waste disposal sites proposed for use by Ontario Hydro may be affected by the release of radioactive gases. Microbes mediate the primary pathways of waste degradation and hence an assessment of their potential to produce gaseous end products from the breakdown of low level waste was performed. Due to a number of unknown variables, assumptions were made regarding environmental and waste conditions that controlled microbial activity; however, it was concluded that 14 C and 3 H would be produced, albeit over a long time scale of about 1500 years for 14 C in the worst case situation

  18. Microbial Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2006-10-01

    The American Academy of Microbiology convened a colloquium March 10-12, 2006, in San Francisco, California, to discuss the production of energy fuels by microbial conversions. The status of research into various microbial energy technologies, the advantages and disadvantages of each of these approaches, research needs in the field, and education and training issues were examined, with the goal of identifying routes for producing biofuels that would both decrease the need for fossil fuels and reduce greenhouse gas emissions. Currently, the choices for providing energy are limited. Policy makers and the research community must begin to pursue a broader array of potential energy technologies. A diverse energy portfolio that includes an assortment of microbial energy choices will allow communities and consumers to select the best energy solution for their own particular needs. Funding agencies and governments alike need to prepare for future energy needs by investing both in the microbial energy technologies that work today and in the untested technologies that will serve the world’s needs tomorrow. More mature bioprocesses, such as ethanol production from starchy materials and methane from waste digestors, will find applications in the short term. However, innovative techniques for liquid fuel or biohydrogen production are among the longer term possibilities that should also be vigorously explored, starting now. Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Alternatively, bacteria can be put to use in microbial fuel cells, where they carry out the direct conversion of biomass into electricity. Microorganisms may also be used some day to make oil and natural gas technologies more efficient by sequestering carbon or by assisting in the recovery of oil and

  19. Physician Decisions to Defer Antiretroviral Therapy in Key Populations: Implications for Reducing Human Immunodeficiency Virus Incidence and Mortality in Malaysia

    OpenAIRE

    Ferro, Enrico G.; Culbert, Gabriel J.; Wickersham, Jeffrey A.; Marcus, Ruthanne; Steffen, Alana D.; Pauls, Heather A.; Westergaard, Ryan P.; Lee, Christopher K.; Kamarulzaman, Adeeba; Altice, Frederick L.

    2017-01-01

    Abstract Background. Antiretroviral therapy (ART) is recommended for all people living with human immunodeficiency virus (HIV), yet physician attitudes and prescribing behaviors toward members of key risk populations may limit ART access and undermine treatment as prevention strategies. Methods. Physicians in Malaysia (N = 214) who prescribe antiretroviral therapy (ART) responded in an Internet-based survey to hypothetical clinical scenarios of HIV patients, varying by key risk population and...

  20. Microbial Reducibility of Fe(III Phases Associated with the Genesis of Iron Ore Caves in the Iron Quadrangle, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Ceth W. Parker

    2013-11-01

    Full Text Available The iron mining regions of Brazil contain thousands of “iron ore caves” (IOCs that form within Fe(III-rich deposits. The mechanisms by which these IOCs form remain unclear, but the reductive dissolution of Fe(III (hydroxides by Fe(III reducing bacteria (FeRB could provide a microbiological mechanism for their formation. We evaluated the susceptibility of Fe(III deposits associated with these caves to reduction by the FeRB Shewanella oneidensis MR-1 to test this hypothesis. Canga, an Fe(III-rich duricrust, contained poorly crystalline Fe(III phases that were more susceptible to reduction than the Fe(III (predominantly hematite associated with banded iron formation (BIF, iron ore, and mine spoil. In all cases, the addition of a humic acid analogue enhanced Fe(III reduction, presumably by shuttling electrons from S. oneidensis to Fe(III phases. The particle size and quartz-Si content of the solids appeared to exert control on the rate and extent of Fe(III reduction by S. oneidensis, with more bioreduction of Fe(III associated with solid phases containing more quartz. Our results provide evidence that IOCs may be formed by the activities of Fe(III reducing bacteria (FeRB, and the rate of this formation is dependent on the physicochemical and mineralogical characteristics of the Fe(III phases of the surrounding rock.

  1. Advanced Microscopy of Microbial Cells

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Regenberg, Birgitte; Sternberg, Claus

    2011-01-01

    microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy...

  2. The catastrophic decline of the Sumatran rhino (Dicerorhinus sumatrensis harrissoni in Sabah: Historic exploitation, reduced female reproductive performance and population viability

    Directory of Open Access Journals (Sweden)

    P. Kretzschmar

    2016-04-01

    Full Text Available The reasons for catastrophic declines of Sumatran rhinos are far from clear and data necessary to improve decisions for conservation management are often lacking. We reviewed literature and assembled a comprehensive data set on surveys of the Sumatran rhino subspecies (Dicerorhinus sumatrensis harrissoni in the Malaysian state of Sabah on Borneo to chart the historical development of the population in Sabah and its exploitation until the present day. We fitted resource selection functions to identify habitat features preferred by a remnant population of rhinos living in the Tabin Wildlife Reserve in Sabah, and ran a series of population viability analyses (PVAs to extract the key demographic parameters most likely to affect population dynamics. We show that as preferred habitat, the individuals in the reserve were most likely encountered in elevated areas away from roads, in close distance to mud-volcanoes, with a low presence of human trespassers and a wallow on site, and within a neighbourhood of dense forest and grassland patches preferably on Fluvisols and Acrisols. Our population viability analyses identified the percentage of breeding females and female lifetime reproductive period as the crucial parameters driving population dynamics, in combination with total protection even moderate improvements could elevate population viability substantially. The analysis also indicates that unrestrained hunting between 1930 and 1950 drastically reduced the historical rhino population in Sabah and that the remnant population could be rescued by combining the effort of total protection and stimulation of breeding activity. Based on our results, we recommend to translocate isolated reproductively healthy individuals to protected locations and to undertake measures to maximise conceptions, or running state-of-the-art reproductive management with assisted reproduction techniques. Our study demonstrates that a judicious combination of techniques can do

  3. Effect of pesticides on soil microbial community.

    Science.gov (United States)

    Lo, Chi-Chu

    2010-07-01

    According to guidelines for the approval of pesticides, information about effects of pesticides on soil microorganisms and soil fertility are required, but the relationships of different structures of pesticides on the growth of various groups of soil microorganisms are not easily predicted. Some pesticides stimulate the growth of microorganisms, but other pesticides have depressive effects or no effects on microorganisms. For examples, carbofuran stimulated the population of Azospirillum and other anaerobic nitrogen fixers in flooded and non-flooded soil, but butachlor reduced the population of Azospirillum and aerobic nitrogen fixers in non-flooded soil. Diuron and chlorotoluron showed no difference between treated and nontreated soil, and linuron showed a strong difference. Phosphorus(P)-contains herbicides glyphosate and insecticide methamidophos stimulated soil microbial growth, but other P-containing insecticide fenamiphos was detrimental to nitrification bacteria. Therefore, the following review presents some data of research carried out during the last 20 years. The effects of twenty-one pesticides on the soil microorganisms associated with nutrient and cycling processes are presented in section 1, and the applications of denaturing gradient gel electrophoresis (DGGE) for studying microbial diversity are discussed in section 2.

  4. Microbial conversion of sulfur dioxide in flue gas to sulfide using bulk drug industry wastewater as an organic source by mixed cultures of sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Rao, A. Gangagni; Ravichandra, P.; Joseph, Johny; Jetty, Annapurna; Sarma, P.N.

    2007-01-01

    Mixed cultures of sulfate reducing bacteria (SRB) were isolated from anaerobic cultures and enriched with SRB media. Studies on batch and continuous reactors for the removal of SO 2 with bulk drug industry wastewater as an organic source using isolated mixed cultures of SRB revealed that isolation and enrichment methodology adopted in the present study were apt to suppress the undesirable growth of anaerobic bacteria other than SRB. Studies on anaerobic reactors showed that process was sustainable at COD/S ratio of 2.2 and above with optimum sulfur loading rate (SLR) of 5.46 kg S/(m 3 day), organic loading rate (OLR) of 12.63 kg COD/(m 3 day) and at hydraulic residence time (HRT) of 8 h. Free sulfide (FS) concentration in the range of 300-390 mg FS/l was found to be inhibitory to mixed cultures of SRB used in the present studies

  5. Microbial Forensics: A Scientific Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Keim, Paul

    2003-02-17

    procedures and training to meet these initial challenges so as minimize disturbance of the evidence. While epidemiology and forensics are similar sciences with similar goals when applied to biocrimes, forensics has additional and more stringent requirements. Maintaining a chain of custody on evidentiary samples is one example of an extra requirement imposed on an investigation of a biocrime. Another issue is the intent in microbial forensics to identify a bioattack organism in greatest detail. If possible, forensic investigations will strive to identify the precise strain and substrain, rather than just to the species level, which might be sufficient in an epidemiological investigation. Although multiple groups have developed lists of bioterrorism target pathogens, these lists are too narrow. An expansion of microorganisms relevant to food and water threats should be considered. Computerized networks should be established to track infectious disease outbreaks in real time. These systems could alert public health and agricultural officials to the existence of a potential bioattack earlier than simply waiting for a report of a suspicious cluster of similar patients. Once a biocrime is suspected, a wide variety of methods are available to identify the microorganism used in the bioattack and to analyze features that might lead to the source of the event. A multi-pronged approach to such an investigation may be preferable, using many available methods-ranging from genomics to sequencing to physiology to analysis of substances in the sample. Microbial forensics will be most effective if there is sufficient basic scientific information concerning microbial genetics, evolution, physiology, and ecology. Strain subtyping analysis will be difficult to interpret if we do not understand some of the basic evolutionary mechanisms and population diversity of pathogens. Phenotypic features associated with evidentiary pathogens also may provide investigative leads, but full exploitation of

  6. Effect of electrokinetic remediation on indigenous microbial activity and community within diesel contaminated soil.

    Science.gov (United States)

    Kim, Seong-Hye; Han, Hyo-Yeol; Lee, You-Jin; Kim, Chul Woong; Yang, Ji-Won

    2010-07-15

    Electrokinetic remediation has been successfully used to remove organic contaminants and heavy metals within soil. The electrokinetic process changes basic soil properties, but little is known about the impact of this remediation technology on indigenous soil microbial activities. This study reports on the effects of electrokinetic remediation on indigenous microbial activity and community within diesel contaminated soil. The main removal mechanism of diesel was electroosmosis and most of the bacteria were transported by electroosmosis. After 25 days of electrokinetic remediation (0.63 mA cm(-2)), soil pH developed from pH 3.5 near the anode to pH 10.8 near the cathode. The soil pH change by electrokinetics reduced microbial cell number and microbial diversity. Especially the number of culturable bacteria decreased significantly and only Bacillus and strains in Bacillales were found as culturable bacteria. The use of EDTA as an electrolyte seemed to have detrimental effects on the soil microbial activity, particularly in the soil near the cathode. On the other hand, the soil dehydrogenase activity was enhanced close to the anode and the analysis of microbial community structure showed the increase of several microbial populations after electrokinetics. It is thought that the main causes of changes in microbial activities were soil pH and direct electric current. The results described here suggest that the application of electrokinetics can be a promising soil remediation technology if soil parameters, electric current, and electrolyte are suitably controlled based on the understanding of interaction between electrokinetics, contaminants, and indigenous microbial community. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Links between root carbohydrates and seasonal pattern of soil microbial activity of diverse european populations of Pinus sylvestris grown in a provenance plantation

    Directory of Open Access Journals (Sweden)

    Barbara Kaliszewska-Rokicka

    2011-01-01

    Full Text Available Activity of soil dehydrogenase (DHA was measured in the mineral soil in a forest stand of 15 to 16-year-old Scots pine (Pinus sylvestris L. from geographically diverse populations, as an indicator of biological activity of soil microorganisms, in a provenance experiment in Poland. The pine populations originated from six European countries (Sweden, Russia, Latvia, Poland, Germany, France and differed widely in aboveground biomass and productivity. Soil DHA during two growing seasons showed pronounced seasonal variability, which was significantly related to the fine root concentration of nonstructural carbohydrates. Higher DHA was found in soil under canopies of the central and southern European populations than in those from more northern parts of the Scots pine range. Significant positive correlation between soil DHA and aboveground tree biomass suggest that these patterns most likely resulted from differences in carbon dynamics and productivity among populations.

  8. Microbial Population Dynamics and Ecosystem Functions of Anoxic/Aerobic Granular Sludge in Sequencing Batch Reactors Operated at Different Organic Loading Rates

    Directory of Open Access Journals (Sweden)

    Enikö Szabó

    2017-05-01

    Full Text Available The granular sludge process is an effective, low-footprint alternative to conventional activated sludge wastewater treatment. The architecture of the microbial granules allows the co-existence of different functional groups, e.g., nitrifying and denitrifying communities, which permits compact reactor design. However, little is known about the factors influencing community assembly in granular sludge, such as the effects of reactor operation strategies and influent wastewater composition. Here, we analyze the development of the microbiomes in parallel laboratory-scale anoxic/aerobic granular sludge reactors operated at low (0.9 kg m-3d-1, moderate (1.9 kg m-3d-1 and high (3.7 kg m-3d-1 organic loading rates (OLRs and the same ammonium loading rate (0.2 kg NH4-N m-3d-1 for 84 days. Complete removal of organic carbon and ammonium was achieved in all three reactors after start-up, while the nitrogen removal (denitrification efficiency increased with the OLR: 0% at low, 38% at moderate, and 66% at high loading rate. The bacterial communities at different loading rates diverged rapidly after start-up and showed less than 50% similarity after 6 days, and below 40% similarity after 84 days. The three reactor microbiomes were dominated by different genera (mainly Meganema, Thauera, Paracoccus, and Zoogloea, but these genera have similar ecosystem functions of EPS production, denitrification and polyhydroxyalkanoate (PHA storage. Many less abundant but persistent taxa were also detected within these functional groups. The bacterial communities were functionally redundant irrespective of the loading rate applied. At steady-state reactor operation, the identity of the core community members was rather stable, but their relative abundances changed considerably over time. Furthermore, nitrifying bacteria were low in relative abundance and diversity in all reactors, despite their large contribution to nitrogen turnover. The results suggest that the OLR has

  9. Characterization of nitrate-reducing and amino acid-using bacteria prominent in nitrotoxin-enriched equine cecal populations

    Science.gov (United States)

    In the present study, populations of equine cecal microbes enriched for enhanced rates of 3-nitro-1-propionic acid (NPA) or nitrate metabolism were diluted and cultured for NPA-metabolizing bacteria on a basal enrichment medium (BEM) or tryptose soy agar (TSA) medium supplemented with either 5 mM NP...

  10. Societal consequences of falls in the older population: Injuries, healthcare costs, and long-term reduced quality of life

    NARCIS (Netherlands)

    K.A. Hartholt (Klaas); E.F. van Beeck (Ed); S. Polinder (Suzanne); N. van der Velde (Nathalie); E.M.M. van Lieshout (Esther); M.J.M. Panneman (Martien); T.J.M. van der Cammen (Tischa); P. Patka (Peter)

    2011-01-01

    textabstractBACKGROUND:: Fall incidents are a major cause of morbidity and mortality in older adults. The aim of this cohort study was to determine the incidence, costs, and quality of life for fall-related injuries in the older Dutch population presenting at the emergency department. METHODS:: Data

  11. Systems biology of Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    Navid, A; Ghim, C; Fenley, A; Yoon, S; Lee, S; Almaas, E

    2008-04-11

    Microbes exist naturally in a wide range of environments, spanning the extremes of high acidity and high temperature to soil and the ocean, in communities where their interactions are significant. We present a practical discussion of three different approaches for modeling microbial communities: rate equations, individual-based modeling, and population dynamics. We illustrate the approaches with detailed examples. Each approach is best fit to different levels of system representation, and they have different needs for detailed biological input. Thus, this set of approaches is able to address the operation and function of microbial communities on a wide range of organizational levels.

  12. Population Abundance of Potentially Pathogenic Organisms in Intestinal Microbiome of Jungle Crow (Corvus macrorhynchos Shown with 16S rRNA Gene-Based Microbial Community Analysis

    Directory of Open Access Journals (Sweden)

    Isamu Maeda

    2013-01-01

    Full Text Available Jungle Crows (Corvus macrorhynchos prefer human habitats because of their versatility in feeding accompanied with human food consumption. Therefore, it is important from a public health viewpoint to characterize their intestinal microbiota. However, no studies have been involved in molecular characterization of the microbiota based on huge and reliable number of data acquisition. In this study, 16S rRNA gene-based microbial community analysis coupled with the next-generation DNA sequencing techniques was applied to the taxonomic classification of intestinal microbiome for three jungle crows. Clustering of the reads into 130 operational taxonomic units showed that at least 70% of analyzed sequences for each crow were highly homologous to Eimeria sp., which belongs to the protozoan phylum Apicomplexa. The microbiotas of three crows also contained potentially pathogenic bacteria with significant percentages, such as the genera Campylobacter and Brachyspira. Thus, the profiling of a large number of 16S rRNA gene sequences in crow intestinal microbiomes revealed the high-frequency existence or vestige of potentially pathogenic microorganisms.

  13. Microbial population dynamics during startup of a full-scale anaerobic digester treating industrial food waste in Kyoto eco-energy project.

    Science.gov (United States)

    Ike, Michihiko; Inoue, Daisuke; Miyano, Tomoki; Liu, Tong Tong; Sei, Kazunari; Soda, Satoshi; Kadoshin, Shiro

    2010-06-01

    The microbial community in a full-scale anaerobic digester (2300m3) treating industrial food waste in the Kyoto Eco-Energy Project was analyzed using terminal restriction fragment length polymorphism for eubacterial and archaeal 16S rRNA genes. Both thermophilic and mesophilic sludge of treated swine waste were seeded to the digestion tank. During the 150-day startup period, coffee grounds as a main food waste, along with potato, kelp and boiled beans, tofu, bean curd lees, and deep-fried bean curd were fed to the digestion process step-by-step (max. 40t/d). Finally, the methane yield reached 360m3/t-feed with 40days' retention time, although temporary accumulation of propionate was observed. Eubacterial communities that formed in the thermophilic digestion tank differed greatly from both thermophilic and mesophilic types of seed sludge. Results suggest that the Actinomyces/Thermomonospora and Ralstonia/Shewanella were contributors for hydrolyzation and degradation of food waste into volatile fatty acids. Acetate-utilizing methanogens, Methanosaeta, were dominant in seed sludges of both types, but they decreased drastically during processing in the digestion tank. Methanosarcina and Methanobrevibacter/Methanobacterium were, respectively, possible main contributors for methane production from acetate and H2 plus CO2. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. Population densities and tree diameter effects associated with verbenone treatments to reduce mountain pine beetle-caused mortality of lodgepole pine.

    Science.gov (United States)

    Progar, R A; Blackford, D C; Cluck, D R; Costello, S; Dunning, L B; Eager, T; Jorgensen, C L; Munson, A S; Steed, B; Rinella, M J

    2013-02-01

    Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), is among the primary causes of mature lodgepole pine, Pinus contorta variety latifolia mortality. Verbenone is the only antiaggregant semiochemical commercially available for reducing mountain pine beetle infestation of lodgepole pine. The success of verbenone treatments has varied greatly in previous studies because of differences in study duration, beetle population size, tree size, or other factors. To determine the ability of verbenone to protect lodgepole pine over long-term mountain pine beetle outbreaks, we applied verbenone treatments annually for 3 to 7 yr at five western United States sites. At one site, an outbreak did not develop; at two sites, verbenone reduced lodgepole pine mortality in medium and large diameter at breast height trees, and at the remaining two sites verbenone was ineffective at reducing beetle infestation. Verbenone reduced mountain pine beetle infestation of lodgepole pine trees in treated areas when populations built gradually or when outbreaks in surrounding untreated forests were of moderate severity. Verbenone did not protect trees when mountain pine beetle populations rapidly increase.

  15. Loss of population levels of immunity to malaria as a result of exposure-reducing interventions: consequences for interpretation of disease trends.

    Directory of Open Access Journals (Sweden)

    Azra C Ghani

    Full Text Available BACKGROUND: The persistence of malaria as an endemic infection and one of the major causes of childhood death in most parts of Africa has lead to a radical new call for a global effort towards eradication. With the deployment of a highly effective vaccine still some years away, there has been an increased focus on interventions which reduce exposure to infection in the individual and -by reducing onward transmission-at the population level. The development of appropriate monitoring of these interventions requires an understanding of the timescales of their effect. METHODS & FINDINGS: Using a mathematical model for malaria transmission which incorporates the acquisition and loss of both clinical and parasite immunity, we explore the impact of the trade-off between reduction in exposure and decreased development of immunity on the dynamics of disease following a transmission-reducing intervention such as insecticide-treated nets. Our model predicts that initially rapid reductions in clinical disease incidence will be observed as transmission is reduced in a highly immune population. However, these benefits in the first 5-10 years after the intervention may be offset by a greater burden of disease decades later as immunity at the population level is gradually lost. The negative impact of having fewer immune individuals in the population can be counterbalanced either by the implementation of highly-effective transmission-reducing interventions (such as the combined use of insecticide-treated nets and insecticide residual sprays for an indefinite period or the concurrent use of a pre-erythrocytic stage vaccine or prophylactic therapy in children to protect those at risk from disease as immunity is lost in the population. CONCLUSIONS: Effective interventions will result in rapid decreases in clinical disease across all transmission settings while population-level immunity is maintained but