WorldWideScience

Sample records for access microbial populations

  1. Modeling Approaches for Describing Microbial Population Heterogeneity

    OpenAIRE

    Lencastre Fernandes, Rita; Gernaey, Krist; Jensen, Anker Degn; Nopens, Ingmar

    2013-01-01

    Although microbial populations are typically described by averaged properties, individual cells present a certain degree of variability. Indeed, initially clonal microbial populations develop into heterogeneous populations, even when growing in a homogeneous environment. A heterogeneous microbial population consists of cells in different states, and it implies a heterogeneous distribution of activities (e.g. respiration, product yield), including different responses to extracellular stimuli. ...

  2. 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

  3. 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.

  4. 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.

  5. Modeling Approaches for Describing Microbial Population Heterogeneity

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita

    population dynamics, in response to the substrate consumption observed during batch cultivation. Cell size and cell cycle position distributions were used to describe the cell population. A two-stage PBM was developed and coupled to an unstructured model describing the extracellular environment. The good...... for cultivations in large-scale reactors, where substrate and oxygen gradients are observed, in comparison to cultivations in well-mixed bench scale reactors. Population balance models (PBM) have been used in a broad range of applications (e.g. crystallization, granulation, flocculation, polymerization processes...... observed to provide a dynamic picture of the interplay between the cells and their surrounding extracellular environment. The work here presented aimed at developing a model framework based on PBM as a tool to further understand the development of heterogeneous microbial populations subjected to varying...

  6. Interactions between Ipomoea aquatica and Microbial Populations

    Institute of Scientific and Technical Information of China (English)

    Kan; Yuanqing; Sun; Ling; Zhang; Ying

    2014-01-01

    [Objective]This paper was to research the water purification mechanism of Ipomoea aquatica and its correlation with algae and rotifer. [Methods]Taking I. aquatica as the test material,Chlorella vulgaris,Scenedesmus obliquus,Microcystis aeroginosa and rotifer Adineta vaga with different densities were added to the hydroponics nutrients solutions of I. aquatica by the hydroponic ecological simulation method. The growth characteristics of I. aquatica,changes of microbial populations and the consumption status of nutrients in the nutritional solution were determined. And the interactions between the plant and the microbial populations were researched. [Results]When I. aquatica seedlings grew to a certain stage,growth of principal root stopped; while the lateral roots emerged greatly; and the nutrition absorption efficiency enhanced. As the inoculation concentration of C. vulgaris increased,root length of I. aquatica increased relatively great due to the competition for nutrients. The competition and allelopathy of M. aeroginosa and S. obliquus restricted the development of root system of I. aquatica. The grazing pressure of Chlorella vulgaris had little effects on M. aeroginosa,but restricted the rapid growth of S. obliquus. [Conclusions]This research provided data support for the application of fish-shrimp-vegetable aquaculture system.

  7. BIOSORPTION OF HYDROPHOBIC ORGANIC POLLUTANTS BY MIXED MICROBIAL POPULATIONS

    Science.gov (United States)

    In recognition of the need to estimate biosorption for natural microbial populations, the variability of partition coefficients for two hydrophobic pollutants to natural populations from a variety of aquatic systems was investigated. Biosorption partition coefficients for pyrene ...

  8. Facilitation as Attenuating of Environmental Stress among Structured Microbial Populations

    OpenAIRE

    Suzana Cláudia Silveira Martins; Sandra Tédde Santaella; Claudia Miranda Martins; Rogério Parentoni Martins

    2016-01-01

    There is currently an intense debate in microbial societies on whether evolution in complex communities is driven by competition or cooperation. Since Darwin, competition for scarce food resources has been considered the main ecological interaction shaping population dynamics and community structure both in vivo and in vitro. However, facilitation may be widespread across several animal and plant species. This could also be true in microbial strains growing under environmental stress. Pure an...

  9. Diversity Generation in Evolving Microbial Populations

    DEFF Research Database (Denmark)

    Markussen, Trine

    diversity has been documented in contemporary respiratory specimens, it is less clear to what extent within-patient diversity contributes to the overall population structure and whether the population is geographically or homogeneously distributed throughout the airways. The focus of this thesis has been...... and maintenance of population diversity of infecting pathogens. Furthermore, fine-tuning of global regulatory networks by modification of transcriptional regulators has fundamental roles in successful adaptation of P. aeruginosa to the CF environment....

  10. 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.

  11. MICROBIAL POPULATION ANALYSIS AS A MEASURE OF ECOSYSTEM RESTORATION

    Science.gov (United States)

    During a controlled oil spill study in a freshwater wetland, four methods were used to track changes in microbial populations in response to in situ remediation treatments, including nutrient amendments and the removal of surface vegetation. Most probable number (MPN) esimates o...

  12. Population distribution, settlement patterns and accessibility across Africa in 2010.

    Directory of Open Access Journals (Sweden)

    Catherine Linard

    Full Text Available The spatial distribution of populations and settlements across a country and their interconnectivity and accessibility from urban areas are important for delivering healthcare, distributing resources and economic development. However, existing spatially explicit population data across Africa are generally based on outdated, low resolution input demographic data, and provide insufficient detail to quantify rural settlement patterns and, thus, accurately measure population concentration and accessibility. Here we outline approaches to developing a new high resolution population distribution dataset for Africa and analyse rural accessibility to population centers. Contemporary population count data were combined with detailed satellite-derived settlement extents to map population distributions across Africa at a finer spatial resolution than ever before. Substantial heterogeneity in settlement patterns, population concentration and spatial accessibility to major population centres is exhibited across the continent. In Africa, 90% of the population is concentrated in less than 21% of the land surface and the average per-person travel time to settlements of more than 50,000 inhabitants is around 3.5 hours, with Central and East Africa displaying the longest average travel times. The analyses highlight large inequities in access, the isolation of many rural populations and the challenges that exist between countries and regions in providing access to services. The datasets presented are freely available as part of the AfriPop project, providing an evidence base for guiding strategic decisions.

  13. Population distribution, settlement patterns and accessibility across Africa in 2010.

    Science.gov (United States)

    Linard, Catherine; Gilbert, Marius; Snow, Robert W; Noor, Abdisalan M; Tatem, Andrew J

    2012-01-01

    The spatial distribution of populations and settlements across a country and their interconnectivity and accessibility from urban areas are important for delivering healthcare, distributing resources and economic development. However, existing spatially explicit population data across Africa are generally based on outdated, low resolution input demographic data, and provide insufficient detail to quantify rural settlement patterns and, thus, accurately measure population concentration and accessibility. Here we outline approaches to developing a new high resolution population distribution dataset for Africa and analyse rural accessibility to population centers. Contemporary population count data were combined with detailed satellite-derived settlement extents to map population distributions across Africa at a finer spatial resolution than ever before. Substantial heterogeneity in settlement patterns, population concentration and spatial accessibility to major population centres is exhibited across the continent. In Africa, 90% of the population is concentrated in less than 21% of the land surface and the average per-person travel time to settlements of more than 50,000 inhabitants is around 3.5 hours, with Central and East Africa displaying the longest average travel times. The analyses highlight large inequities in access, the isolation of many rural populations and the challenges that exist between countries and regions in providing access to services. The datasets presented are freely available as part of the AfriPop project, providing an evidence base for guiding strategic decisions. PMID:22363717

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-06-01

    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{sub 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{sub 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.

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

    Science.gov (United States)

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

    1998-06-01

    The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganisms, agents of foodborn diseases. The aim of this work is to evaluate the killing effect of gamma radiation of the resident microbial population of pork and beef casings, to improve their hygiene and safety. Portions of fresh pork (small intestines and colon) and dry beef casings were irradiated in a Cobalt 60 source with 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.

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

    International Nuclear Information System (INIS)

    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 D10 values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D10 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

  17. Self-driven jamming in growing microbial populations

    Science.gov (United States)

    Delarue, Morgan; Hartung, Jörn; Schreck, Carl; Gniewek, Pawel; Hu, Lucy; Herminghaus, Stephan; Hallatschek, Oskar

    2016-08-01

    In natural settings, microbes tend to grow in dense populations where they need to push against their surroundings to accommodate space for new cells. The associated contact forces play a critical role in a variety of population-level processes, including biofilm formation, the colonization of porous media, and the invasion of biological tissues. Although mechanical forces have been characterized at the single-cell level, it remains elusive how collective pushing forces result from the combination of single-cell forces. Here, we reveal a collective mechanism of confinement, which we call self-driven jamming, that promotes the build-up of large mechanical pressures in microbial populations. Microfluidic experiments on budding yeast populations in space-limited environments show that self-driven jamming arises from the gradual formation and sudden collapse of force chains driven by microbial proliferation, extending the framework of driven granular matter. The resulting contact pressures can become large enough to slow down cell growth, to delay the cell cycle in the G1 phase, and to strain or even destroy the micro-environment through crack propagation. Our results suggest that self-driven jamming and build-up of large mechanical pressures is a natural tendency of microbes growing in confined spaces, contributing to microbial pathogenesis and biofouling.

  18. CRISPR-induced distributed immunity in microbial populations.

    Directory of Open Access Journals (Sweden)

    Lauren M Childs

    Full Text Available In bacteria and archaea, viruses are the primary infectious agents, acting as virulent, often deadly pathogens. A form of adaptive immune defense known as CRISPR-Cas enables microbial cells to acquire immunity to viral pathogens by recognizing specific sequences encoded in viral genomes. The unique biology of this system results in evolutionary dynamics of host and viral diversity that cannot be fully explained by the traditional models used to describe microbe-virus coevolutionary dynamics. Here, we show how the CRISPR-mediated adaptive immune response of hosts to invading viruses facilitates the emergence of an evolutionary mode we call distributed immunity - the coexistence of multiple, equally-fit immune alleles among individuals in a microbial population. We use an eco-evolutionary modeling framework to quantify distributed immunity and demonstrate how it emerges and fluctuates in multi-strain communities of hosts and viruses as a consequence of CRISPR-induced coevolution under conditions of low viral mutation and high relative numbers of viral protospacers. We demonstrate that distributed immunity promotes sustained diversity and stability in host communities and decreased viral population density that can lead to viral extinction. We analyze sequence diversity of experimentally coevolving populations of Streptococcus thermophilus and their viruses where CRISPR-Cas is active, and find the rapid emergence of distributed immunity in the host population, demonstrating the importance of this emergent phenomenon in evolving microbial communities.

  19. Growth dynamics and the evolution of cooperation in microbial populations

    Science.gov (United States)

    Cremer, Jonas; Melbinger, Anna; Frey, Erwin

    2012-02-01

    Microbes providing public goods are widespread in nature despite running the risk of being exploited by free-riders. However, the precise ecological factors supporting cooperation are still puzzling. Following recent experiments, we consider the role of population growth and the repetitive fragmentation of populations into new colonies mimicking simple microbial life-cycles. Individual-based modeling reveals that demographic fluctuations, which lead to a large variance in the composition of colonies, promote cooperation. Biased by population dynamics these fluctuations result in two qualitatively distinct regimes of robust cooperation under repetitive fragmentation into groups. First, if the level of cooperation exceeds a threshold, cooperators will take over the whole population. Second, cooperators can also emerge from a single mutant leading to a robust coexistence between cooperators and free-riders. We find frequency and size of population bottlenecks, and growth dynamics to be the major ecological factors determining the regimes and thereby the evolutionary pathway towards cooperation.

  20. Population-reaction model and microbial experimental ecosystems for understanding hierarchical dynamics of ecosystems.

    Science.gov (United States)

    Hosoda, Kazufumi; Tsuda, Soichiro; Kadowaki, Kohmei; Nakamura, Yutaka; Nakano, Tadashi; Ishii, Kojiro

    2016-02-01

    Understanding ecosystem dynamics is crucial as contemporary human societies face ecosystem degradation. One of the challenges that needs to be recognized is the complex hierarchical dynamics. Conventional dynamic models in ecology often represent only the population level and have yet to include the dynamics of the sub-organism level, which makes an ecosystem a complex adaptive system that shows characteristic behaviors such as resilience and regime shifts. The neglect of the sub-organism level in the conventional dynamic models would be because integrating multiple hierarchical levels makes the models unnecessarily complex unless supporting experimental data are present. Now that large amounts of molecular and ecological data are increasingly accessible in microbial experimental ecosystems, it is worthwhile to tackle the questions of their complex hierarchical dynamics. Here, we propose an approach that combines microbial experimental ecosystems and a hierarchical dynamic model named population-reaction model. We present a simple microbial experimental ecosystem as an example and show how the system can be analyzed by a population-reaction model. We also show that population-reaction models can be applied to various ecological concepts, such as predator-prey interactions, climate change, evolution, and stability of diversity. Our approach will reveal a path to the general understanding of various ecosystems and organisms. PMID:26747638

  1. Facilitation as Attenuating of Environmental Stress among Structured Microbial Populations

    Directory of Open Access Journals (Sweden)

    Suzana Cláudia Silveira Martins

    2016-01-01

    Full Text Available There is currently an intense debate in microbial societies on whether evolution in complex communities is driven by competition or cooperation. Since Darwin, competition for scarce food resources has been considered the main ecological interaction shaping population dynamics and community structure both in vivo and in vitro. However, facilitation may be widespread across several animal and plant species. This could also be true in microbial strains growing under environmental stress. Pure and mixed strains of Serratia marcescens and Candida rugosa were grown in mineral culture media containing phenol. Growth rates were estimated as the angular coefficients computed from linearized growth curves. Fitness index was estimated as the quotient between growth rates computed for lineages grown in isolation and in mixed cultures. The growth rates were significantly higher in associated cultures than in pure cultures and fitness index was greater than 1 for both microbial species showing that the interaction between Serratia marcescens and Candida rugosa yielded more efficient phenol utilization by both lineages. This result corroborates the hypothesis that facilitation between microbial strains can increase their fitness and performance in environmental bioremediation.

  2. [Vulnerable populations and access to care].

    Science.gov (United States)

    Castello, Christine; Michard-Lenoir, Anne-Pascale; Allemand, Robert

    2012-01-01

    Precariousness is a very complex concept that brings together a diverse and fragmented population. The interest in comparing views and opinions is clear for understanding of this phenomenon. A physician in the paediatric emergency unit of a hospital and the head of a "Medecins du Monde" branch evoke the different faces of precariousness. A difficult and sometimes poignant reality, which health care providers must try to cope with. PMID:23074804

  3. 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...

  4. Population dynamics of microbial communities in the zebrafish gut

    Science.gov (United States)

    Jemielita, Matthew; Taormina, Michael; Burns, Adam; Hampton, Jennifer; Rolig, Annah; Wiles, Travis; Guillemin, Karen; Parthasarathy, Raghuveer

    2015-03-01

    The vertebrate intestine is home to a diverse microbial community, which plays a crucial role in the development and health of its host. Little is known about the population dynamics and spatial structure of this ecosystem, including mechanisms of growth and interactions between species. We have constructed an experimental model system with which to explore these issues, using initially germ-free larval zebrafish inoculated with defined communities of fluorescently tagged bacteria. Using light sheet fluorescence microscopy combined with computational image analysis we observe and quantify the entire bacterial community of the intestine during the first 24 hours of colonization, during which time the bacterial population grows from tens to tens of thousands of bacteria. We identify both individual bacteria and clusters of bacteria, and quantify the growth rate and spatial distribution of these distinct subpopulations. We find that clusters of bacteria grow considerably faster than individuals and are located in specific regions of the intestine. Imaging colonization by two species reveals spatial segregation and competition. These data and their analysis highlight the importance of spatial organization in the establishment of gut microbial communities, and can provide inputs to physical models of real-world ecological dynamics.

  5. Population access to new vaccines in European countries.

    Science.gov (United States)

    Blank, Patricia R; Schwenkglenks, Matthias; Sardos, Christelle Saint; Patris, Julien; Szucs, Thomas D

    2013-06-12

    Time from registration to population access to new vaccines can take considerable time in European countries. Reasons might be found in the regulatory framework, decision-making processes or the assessment of vaccines by evaluating bodies. The aim of this study was to determine whether some decision-making processes can explain between-country differences in the time to population access to new vaccination programs. Information gathered from a survey among European National Vaccine Industry Groups was combined with information from official health authorities, vaccine manufacturers and literature published. Firstly, a retrospective survey was conducted to measure access time to new vaccines against three diseases in 17 European countries. Secondly, qualitative information on the country-specific decision-making frameworks for the introduction of new "vaccination programs" was identified in a cross-sectional survey. Spearman's rank correlation coefficients (ρ) were used for data analysis. The median access time to new vaccines was 6.4 years (95% confidence interval: 5.7-7.1 years) post marketing authorization. National assessments underlying immunization policy decisions (recommendation phase) absorbed most of the access time. Correlation analysis suggested that processes with established timelines and clarity in regard to vaccine evaluation criteria used could ameliorate the effectiveness of the decision-making process. In order to reduce the time to access for new, beneficial vaccines, the underlying vaccination recommendation, implementation and funding process needs to be understood and optimized, where necessary. PMID:23632307

  6. Microbial population in rotten living body of Salix matsudana

    Institute of Scientific and Technical Information of China (English)

    Zou Li; Chi Yujie; Xi Shuhua

    1999-01-01

    The microbial population in rotten living body of Salix matsudana caused by Trametes suaveolens (L.)was researched. 11 bacteria species (1 species of Bacillus, 2 species of Clostridium and 8 species of non-brood-cell bacteria), 1 species of Actinomyces that belongs to Lavendulac, 8 species of fungi and 6 species of Trichoderma were isolated from rotten trunk. The hyphae of Trametes suaveolens mainly existed between rotten sections and discoloration sections. in over-rotten section and healthy section the fungi (Trametes suaveolens)were not isolated. The microbes that lived in the discoloration section were the most in kinds and number and they were the pioneer microbes of wood rotting. Only after they dwelled in wood and eliminated its rot-resistance,could wood-rotting fungi invade wood and caused wood-rotting.

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

    International Nuclear Information System (INIS)

    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

  8. 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

  9. Microbial population in phyllosphere of mangroves grow in different salinity zones of Bhitarkanika (India).

    OpenAIRE

    Gupta, Nibha; Mishra, Srilekha; Basak, Uday Chand

    2009-01-01

    Microbial population in phyllosphere of mangroves grow in different salinity zones of Bhitarkanika (India). The bacterial and fungal populations in phyllosphere of mangrove plants were investigated in order to evaluate differences in their occurrence associated with host species. Study sites included relatively undisturbed and purely mangrove area that were selected for sampling from both the low and intermediate salinity zones. Microbial population count was analyzed in 11 and 14 different a...

  10. Evaluating digestion efficiency in full-scale anaerobic digesters by identifying active microbial populations through the lens of microbial activity

    Science.gov (United States)

    Mei, Ran; Narihiro, Takashi; Nobu, Masaru K.; Kuroda, Kyohei; Liu, Wen-Tso

    2016-09-01

    Anaerobic digestion is a common technology to biologically stabilize wasted solids produced in municipal wastewater treatment. Its efficiency is usually evaluated by calculating the reduction in volatile solids, which assumes no biomass growth associated with digestion. To determine whether this assumption is valid and further evaluate digestion efficiency, this study sampled 35 digester sludge from different reactors at multiple time points together with the feed biomass in a full-scale water reclamation plant at Chicago, Illinois. The microbial communities were characterized using Illumina sequencing technology based on 16S rRNA and 16S rRNA gene (rDNA). 74 core microbial populations were identified and represented 58.7% of the entire digester community. Among them, active populations were first identified using the ratio of 16S rRNA and 16S rDNA (rRNA/rDNA) for individual populations, but this approach failed to generate consistent results. Subsequently, a recently proposed mass balance model was applied to calculate the specific growth rate (μ), and this approach successfully identified active microbial populations in digester (positive μ) that could play important roles than those with negative μ. It was further estimated that 82% of microbial populations in the feed sludge were digested in comparison with less than 50% calculated using current equations.

  11. Evaluating digestion efficiency in full-scale anaerobic digesters by identifying active microbial populations through the lens of microbial activity

    Science.gov (United States)

    Mei, Ran; Narihiro, Takashi; Nobu, Masaru K.; Kuroda, Kyohei; Liu, Wen-Tso

    2016-01-01

    Anaerobic digestion is a common technology to biologically stabilize wasted solids produced in municipal wastewater treatment. Its efficiency is usually evaluated by calculating the reduction in volatile solids, which assumes no biomass growth associated with digestion. To determine whether this assumption is valid and further evaluate digestion efficiency, this study sampled 35 digester sludge from different reactors at multiple time points together with the feed biomass in a full-scale water reclamation plant at Chicago, Illinois. The microbial communities were characterized using Illumina sequencing technology based on 16S rRNA and 16S rRNA gene (rDNA). 74 core microbial populations were identified and represented 58.7% of the entire digester community. Among them, active populations were first identified using the ratio of 16S rRNA and 16S rDNA (rRNA/rDNA) for individual populations, but this approach failed to generate consistent results. Subsequently, a recently proposed mass balance model was applied to calculate the specific growth rate (μ), and this approach successfully identified active microbial populations in digester (positive μ) that could play important roles than those with negative μ. It was further estimated that 82% of microbial populations in the feed sludge were digested in comparison with less than 50% calculated using current equations. PMID:27666090

  12. Effect of Lanthanum on Major Microbial Populations in Red Soil

    Institute of Scientific and Technical Information of China (English)

    CHUHAIYAN; WANGJUNHUA; 等

    2001-01-01

    Pure culture and pot culture experiments were carried out to study the effect of lanthanum(La)on bacteria,actinomyces and fungus,and some microbial physiological groups,nitrifir,azotobacter and phos-phobacteria in a red soil taken form the Ecological Experimental Station of Red Soil,the Chinese Academy of Sciences,Jiangxi Province.LaCl3 was added into media at levels of 0,25,50,100,150,200,250 and 500 mg L-1 in the pure culture experiment ,and into soil samples in porcelain pots before rice growing at levles of 0,6,30,150,300,600 and 900 mg kg-1 dry soil in the pot culture experiment.The populations of the three soil microbes in the pure cultre experiment decreased with the addition level of La,indicating that La was toxic to the soil microbes in pure culture ,and the sensitivity of the 3 major mircrobial types to La was in a decreasing order of actinomyces>bacteria>fungus.In the pot experiment,La had slightly stimulaive effect on soil bacteria and actinomyces when applied at olw concentrations while had inhibitory effect on soil bacteria,actinomyces and fungus at high concentrations.When the concentration of La Was low,soil azotobacter was stimulated slightly while soil nitrifier was stimulated strongly and the maximum increase was up to 50%.When the concentration of La was highy,both soil aztobacter and nitrifier ware inhibited ,and the inhibition of La to the nitrifier increased with La conentration,La added at all the levels had stimulative effect on soil inorgaic and organic phosphobacteria.Among the 4 physiological groups,soil nitrifier was most sensitive to La,so,it migh be reasonble to assume that soil nitrifier was a sensitive indicator for evaluating the biological and environmental effects of rare earths.

  13. MICROBIAL POPULATION CHANGES DURING BIOREMEDIATION OF AN EXPERIMENTAL OIL SPILL

    Science.gov (United States)

    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 + nutrients, and oil + nutrients + an indigenous inoculum) were applied. In-situ microbial community str...

  14. Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology.

    Science.gov (United States)

    Wagai, Rota; Kishimoto-Mo, Ayaka W; Yonemura, Seiichiro; Shirato, Yasuhito; Hiradate, Syuntaro; Yagasaki, Yasumi

    2013-04-01

    Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (<1.6 and 1.6-1.8 g cm(-3) ) and bulk soil was measured by solid-state (13) C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for

  15. Oxygen Effects on Thermophilic Microbial Populations in Biofilters Treating Nitric Oxide Containing Off-Gas Streams

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Brady Douglas; Apel, William Arnold; Smith, William Aaron

    2004-04-01

    Electricity generation from coal has increased by an average of 51 billion kWh per year over the past 3 years. For this reason cost-effective strategies to control nitrogen oxides (NOx) from coal-fired power plant combustion gases must be developed. Compost biofilters operated at 55°C at an empty bed contact time (EBCT) of 13 seconds were shown to be feasible for removal of nitric oxide (NO) from synthetic flue gas. Denitrifying microbial populations in these biofilters were shown to reduce influent NO feeds by 90 to 95% at inlet NO concentrations of 500 ppmv. Oxygen was shown to have a significant effect on the NO removal efficiency demonstrated by these biofilters. Two biofilters were set up under identical conditions for the purpose of monitoring NO removal as well as changes in the microbial population in the bed medium under anaerobic and aerobic conditions. Changes in the microbial population were monitored to determine the maximum oxygen tolerance of a denitrifying biofilter as well as methods of optimizing microbial populations capable of denitrification in the presence of low oxygen concentrations. Nitric oxide removal dropped to between 10 and 20% when oxygen was present in the influent stream. The inactive compost used to pack the biofilters may have also caused the decreased NO removal efficiency compared to previous biofiltration experiments. Analysis of the bed medium microbial population using environmental scanning electron microscopy indicated significant increases in biomass populating the surface of the compost when compared to unacclimated compost.

  16. Ecological perspectives on synthetic biology: insights from microbial population biology

    OpenAIRE

    Ana E. Escalante; Rebolleda-Gómez, María; Benítez, Mariana; Travisano, Michael

    2015-01-01

    The metabolic capabilities of microbes are the basis for many major biotechnological advances, exploiting microbial diversity by selection or engineering of single strains. However, there are limits to the advances that can be achieved with single strains, and attention has turned toward the metabolic potential of consortia and the field of synthetic ecology. The main challenge for the synthetic ecology is that consortia are frequently unstable, largely because evolution by constituent member...

  17. Studying microbial populations in relation to thick juice storage

    OpenAIRE

    Justé, Annelies; Krause, M.S.; Lievens, Bart; Klingeberg, M; Michiels, Christiaan; Marsh, T.L.; Willems, Kris

    2006-01-01

    Background and Aims: Storing sugar extracts as thick juice, a form of sucrose syrup, is common practice in the sugar industry. Even under good storage practices, microbiological problems can sometimes occur. Improving control of these microflora-related problems requires greater understanding of microbial dynamics of thick juice storage. Therefore, the objective of this study was to identify the microflora associated with thick juice degradation in order to define better process controls....

  18. Microbial Population Changes during Bioremediation of an Experimental Oil Spill

    OpenAIRE

    Macnaughton, Sarah J.; Stephen, John R.; Venosa, Albert D.; Davis, Gregory A.; Chang, Yun-juan; White, David C.

    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 decontaminat...

  19. Quantitative Modeling of Microbial Population Responses to Chronic Irradiation Combined with Other Stressors

    OpenAIRE

    Shuryak, Igor; Dadachova, Ekaterina

    2016-01-01

    Microbial population responses to combined effects of chronic irradiation and other stressors (chemical contaminants, other sub-optimal conditions) are important for ecosystem functioning and bioremediation in radionuclide-contaminated areas. Quantitative mathematical modeling can improve our understanding of these phenomena. To identify general patterns of microbial responses to multiple stressors in radioactive environments, we analyzed three data sets on: (1) bacteria isolated from soil co...

  20. Modeling the impact of the indigenous microbial population on the maximum population density of Salmonella on alfalfa

    NARCIS (Netherlands)

    Rijgersberg, H.; Nierop Groot, M.N.; Tromp, S.O.; Franz, E.

    2013-01-01

    Within a microbial risk assessment framework, modeling the maximum population density (MPD) of a pathogenic microorganism is important but often not considered. This paper describes a model predicting the MPD of Salmonella on alfalfa as a function of the initial contamination level, the total count

  1. Variations of dominant microbial populations in groundwater in response to the leachate from Laogang Landfill

    Institute of Scientific and Technical Information of China (English)

    TIAN Yang-jie; YANG Hong; LI Dao-tang; LIN Zhi-xin

    2005-01-01

    Temporal changes of dominant microbial populations in groundwater in response to the leachate from Shanghai Laogang Landfill were investigated. Concentrations of dissolved redox-relevant species in groundwater suggested that the dominating redox process had changed from denitrification to methane-production/sulfate-reduction due to landfilling. Dominant microbial populations were determined using restriction fragment length polymorphism(RFLP) analyses of 16S rRNA gene libraries, which were further studied by sequencing and phylogenetic analyses. The results indicated that obvious shifts of dominant microbial populations had occurred in groundwater in response to the pollution of leachate. The closest relatives of some dominant clones are accordant with the dominating redox processes determined by hydrochemical analyses, based on the GenBank's indications on the ability to perform redox reactions.

  2. The Biodiversity Changes in the Microbial Population of Soils Contaminated with Crude Oil.

    Science.gov (United States)

    Abbasian, Firouz; Lockington, Robin; Megharaj, Mallavarapu; Naidu, Ravi

    2016-06-01

    Crude oil spills resulting from excavation, transportation and downstream processes can cause intensive damage to living organisms and result in changes in the microbial population of that environment. In this study, we used a pyrosequencing analysis to investigate changes in the microbial population of soils contaminated with crude oil. Crude oil contamination in soil resulted in the creation of a more homogenous population of microorganisms dominated by members of the Actinomycetales, Clostridiales and Bacillales (all belonging to Gram-positive bacteria) as well as Flavobacteriales, Pseudomonadales, Burkholderiales, Rhizobiales and Sphingomonadales (all belonging to Gram-negative bacteria). These changes in the biodiversity decreased the ratios of chemoheterotrophic bacteria at higher concentrations of crude oil contamination, with these being replaced by photoheterotrophic bacteria, mainly Rhodospirillales. Several of the dominant microbial orders in the crude oil contaminated soils are able to degrade crude oil hydrocarbons and therefore are potentially useful for remediation of crude oil in contaminated sites.

  3. Microbial population of shredded carrot in modified atmosphere packaging as related to irradiation treatment

    International Nuclear Information System (INIS)

    Shredded carrots in modified atmosphere packaging were treated with low-dose irradiation of 0.5 kGy in order to determine whether additional reduction of microbial population would be achieved for carrots previously treated with chlorine. Commercially prepared shredded carrots treated with irradiation had a mean microbial population of 1300 CFU/g at the expiration date (9 days after irradiation) compared with 87,000 CFU/g for nonirradiated, chlorinated controls. Oxygen content of the headspace gas and ethanol content of the carrots were not significantly affected. Irradiation appears to be a suitable technology for shredded carrots

  4. Radiation resistance of the natural microbial population in buffer materials

    International Nuclear Information System (INIS)

    The radiation sensitivity of naturally occurring microorganisms in buffer materials was investigated as well as the sensitivity of Bacillus subtillis spores and Acinetobacter radioresistens in a buffer matrix. The D10 values obtained in these radiation experiments varied from 0.34 to 1.68 kGy and it was calculated that the surface of a nuclear fuel waste container would be sterilized in 9 to 33 d after emplacement, depending on the type of container, and the initial bioburden. This suggests that formation of biofilms and microbially influenced corrosion would not be of concern of some time after emplacement. The results also indicated that sterilization throughout a 25 cm thick buffer layer is unlikely and that repopulation of the container surface after some time is a possibility, depending on the mobility of microbes in compacted buffer material

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

    International Nuclear Information System (INIS)

    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

  6. Genetic Diversity Affects the Daily Transcriptional Oscillations of Marine Microbial Populations.

    Science.gov (United States)

    Shilova, Irina N; Robidart, Julie C; DeLong, Edward F; Zehr, Jonathan P

    2016-01-01

    Marine microbial communities are genetically diverse but have robust synchronized daily transcriptional patterns at the genus level that are similar across a wide variety of oceanic regions. We developed a microarray-inspired gene-centric approach to resolve transcription of closely-related but distinct strains/ecotypes in high-throughput sequence data. Applying this approach to the existing metatranscriptomics datasets collected from two different oceanic regions, we found unique and variable patterns of transcription by individual taxa within the abundant picocyanobacteria Prochlorococcus and Synechococcus, the alpha Proteobacterium Pelagibacter and the eukaryotic picophytoplankton Ostreococcus. The results demonstrate that marine microbial taxa respond differentially to variability in space and time in the ocean. These intra-genus individual transcriptional patterns underlie whole microbial community responses, and the approach developed here facilitates deeper insights into microbial population dynamics.

  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. 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.

  9. A RESTful API for accessing microbial community data for MG-RAST.

    Directory of Open Access Journals (Sweden)

    Andreas Wilke

    2015-01-01

    Full Text Available Metagenomic sequencing has produced significant amounts of data in recent years. For example, as of summer 2013, MG-RAST has been used to annotate over 110,000 data sets totaling over 43 Terabases. With metagenomic sequencing finding even wider adoption in the scientific community, the existing web-based analysis tools and infrastructure in MG-RAST provide limited capability for data retrieval and analysis, such as comparative analysis between multiple data sets. Moreover, although the system provides many analysis tools, it is not comprehensive. By opening MG-RAST up via a web services API (application programmers interface we have greatly expanded access to MG-RAST data, as well as provided a mechanism for the use of third-party analysis tools with MG-RAST data. This RESTful API makes all data and data objects created by the MG-RAST pipeline accessible as JSON objects. As part of the DOE Systems Biology Knowledgebase project (KBase, http://kbase.us we have implemented a web services API for MG-RAST. This API complements the existing MG-RAST web interface and constitutes the basis of KBase's microbial community capabilities. In addition, the API exposes a comprehensive collection of data to programmers. This API, which uses a RESTful (Representational State Transfer implementation, is compatible with most programming environments and should be easy to use for end users and third parties. It provides comprehensive access to sequence data, quality control results, annotations, and many other data types. Where feasible, we have used standards to expose data and metadata. Code examples are provided in a number of languages both to show the versatility of the API and to provide a starting point for users. We present an API that exposes the data in MG-RAST for consumption by our users, greatly enhancing the utility of the MG-RAST service.

  10. The shift of microbial population composition accompanying the injected water flowing in the water-flooding petroleum reservoirs

    OpenAIRE

    P. K. Gao; G. Q. Li; H. M. Tian; Y. S. Wang; Sun, H W; T. Ma

    2014-01-01

    In water-flooding petroleum reservoir, microbial populations in injected water are expected to migrate into oil-bearing strata and reach production wells. To demonstrate this, we firstly investigated microbial compositions in a homogeneous sandstone reservoir. The results indicated that the injected water harbored more microbial cells than produced water, and the shared populations and their abundance accounted for a minor fraction in injected water, while dominated i...

  11. The effect of bioremediation on the microbial populations of oiled beaches in Prince William Sound, Alaska

    International Nuclear Information System (INIS)

    Bioremediation, the stimulation of the natural process of biodegradation, played an important role in the cleanup of the oil spill from the Exxon Valdez in Prince William Sound, Alaska. Since there were already substantial indigenous populations of oil-degrading microbes in the area, it was apparent that degradation was likely to be nutrient - not microbial - limited. Bioremediation therefore involved the application of carefully selected fertilizers to provide assimilable nitrogen and phosphorus to the indigenous organisms, with the intent to stimulate their activity and enhance their numbers. The authors show here that the indigenous microbial populations were indeed substantially increased, throughout the sound, approximately one month after wide-spread fertilizer applications in both 1989 and 1990. Furthermore, while oil-degrading bacteria made up a significant fraction of the microbial populations on contaminated beaches in September and October 1989, they had declined to less than 1 percent by the summer of 1990, suggesting that the microbial populations on the shorelines were returning to their prespill conditions

  12. 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

    importance for improving microbial cell factory processes. Results: In this work, a dual reporter system was developed and applied to map growth and cell fitness heterogeneities within budding yeast populations during aerobic cultivation in well-mixed bioreactors. The reporter strain, which was based...

  13. STATUS OF SOIL MICROBIAL POPULATION, ENZYMATIC ACTIVITY AND BIOMASS OF SELECTED NATURAL, SECONDARY AND REHABILITATED FORESTS

    Directory of Open Access Journals (Sweden)

    K. S. Daljit Singh

    2013-01-01

    Full Text Available Substantial clearance of forests and conversion of forest into various land use types contribute to deterioration of soil fertility and associated nutrients loss. Soils from natural and rehabilitated forest in Chikus Forest Reserve and also enrichment planting forest and secondary forest of Tapah Hill Forest Reserve, Perak, Malaysia were selected in order to assess the influence of land use change on biological properties. This study was carried out to provide fundamental information on soil biological properties and also to compare the differences between natural forest, mono-rehabilitated forest, mixed planting forest and natural regenerated forest (secondary forest. Six subplots (20×20 m were established at each study plot and soil samples were collected at the depths of 0-15 cm (topsoil and 15-30 cm (subsoil. Soil microbial population was determined using spread-plate technique. Fluorescein Diacetate (FDA hydrolysis was used to assess the amount of microbial enzymatic activity for each forest plot. Soil Microbial Biomass C (MBC and N (MBN were extracted using chloroform fumigation extraction technique and the amount of MBC was determined by dichromate digestion, while MBN via Kjeldahl digestion technique. Soil acidity was determined by pH meter and moisture content was elucidated using gravimetric method. The levels of microbial population of bacterial and fungal at natural significantly exceeded the corresponding values of rehabilitated and secondary forest. However, microbial population is much higher in rehabilitated forest of Tapah Hill compared to that of secondary forest and also Chikus Forest Reserve planted forest which proves that rehabilitation activities do help increase the level of microbial community in the soils. Longer period of time after planting as in enrichment planting compared to mono planting of S. leprosula plantation showed that restoring and recovery of the planted forest needed time. Deforestation activities

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

    OpenAIRE

    Sosanka Protim SANDILYA; Anuradha GOGOI; Pinky Moni BHUYAN; Dip Kumar GOGOI

    2014-01-01

    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 populatio...

  15. Effect of hybrid poplar trees on microbial populations important to hazardous waste bioremediation

    International Nuclear Information System (INIS)

    Microbial concentrations of denitrifiers, pseudomonads, and monoaromatic petroleum hydrocarbon (BTX) degraders were significantly higher (p < 0.1) in soil samples from the rhizosphere of poplar trees than in adjacent agricultural soils, and atrazine degraders were found only in one rhizosphere sample. The relative abundance of these phenotypes (as a fraction of total heterotrophs) was not significantly different between rhizosphere and surrounding soils. Therefore, the poplar rhizosphere enhanced the growth of microbial populations that participate in natural bioremediation without exerting selective pressure for them

  16. 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.

  17. Effects of fertilizers on soil’s microbial growth and populations: a review

    Directory of Open Access Journals (Sweden)

    Ojo OI

    2015-07-01

    Full Text Available Soil nutrients availability and decomposition of organic matter depends on microorganism but there are little available literatures on the possible effects of nutrients fixing chemicals and substances on the survival and population distribution of various microbes. Also, because of importance of organic and inorganic fertilizers to increase the soil microorganisms needed for the growth of plants there is need for comprehensive review of existing literature on the subject. This paper reviewed the effects of fertilizers on soil’s microbial growth and populations in available literatures. Various studies agreed that low microbe population due to lack of organic matter can be easily rectified by amending the soil with fertilizers and organic matter and allowing time for microbial growth therefore jump-starting the reproduction of microbes by adding beneficial microbes along with organic matter. Microbe improves soil structure by the humus they create while digesting organic matter and also help in nitrogen fixing.

  18. Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Abulencia, C.B.; Wyborski, D.L.; Garcia, J.; Podar, M.; Chen, W.; Chang, S.H.; Chang, H.W.; Watson, D.; Brodie,E.I.; Hazen, T.C.; Keller, M.

    2005-12-10

    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 ?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 percent 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 percent 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.

  19. Microbial Genomics of a Host-Associated Commensal Bacterium in Fragmented Populations of Endangered Takahe.

    Science.gov (United States)

    Grange, Zoë L; Gartrell, Brett D; Biggs, Patrick J; Nelson, Nicola J; Anderson, Marti; French, Nigel P

    2016-05-01

    Isolation of wildlife into fragmented populations as a consequence of anthropogenic-mediated environmental change may alter host-pathogen relationships. Our understanding of some of the epidemiological features of infectious disease in vulnerable populations can be enhanced by the use of commensal bacteria as a proxy for invasive pathogens in natural ecosystems. The distinctive population structure of a well-described meta-population of a New Zealand endangered flightless bird, the takahe (Porphyrio hochstetteri), provided a unique opportunity to investigate the influence of host isolation on enteric microbial diversity. The genomic epidemiology of a prevalent rail-associated endemic commensal bacterium was explored using core genome and ribosomal multilocus sequence typing (rMLST) of 70 Campylobacter sp. nova 1 isolated from one third of the takahe population resident in multiple locations. While there was evidence of recombination between lineages, bacterial divergence appears to have occurred and multivariate analysis of 52 rMLST genes revealed location-associated differentiation of C. sp. nova 1 sequence types. Our results indicate that fragmentation and anthropogenic manipulation of populations can influence host-microbial relationships, with potential implications for niche adaptation and the evolution of micro-organisms in remote environments. This study provides a novel framework in which to explore the complex genomic epidemiology of micro-organisms in wildlife populations. PMID:26707136

  20. 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.

  1. Microbial Diversity and Population Structure of Extremely Acidic Sulfur-Oxidizing Biofilms From Sulfidic Caves

    Science.gov (United States)

    Jones, D.; Stoffer, T.; Lyon, E. H.; Macalady, J. L.

    2005-12-01

    Extremely acidic (pH 0-1) microbial biofilms called snottites form on the walls of sulfidic caves where gypsum replacement crusts isolate sulfur-oxidizing microorganisms from the buffering action of limestone host rock. We investigated the phylogeny and population structure of snottites from sulfidic caves in central Italy using full cycle rRNA methods. A small subunit rRNA bacterial clone library from a Frasassi cave complex snottite sample contained a single sequence group (>60 clones) similar to Acidithiobacillus thiooxidans. Bacterial and universal rRNA clone libraries from other Frasassi snottites were only slightly more diverse, containing a maximum of 4 bacterial species and probably 2 archaeal species. Fluorescence in situ hybridization (FISH) of snottites from Frasassi and from the much warmer Rio Garrafo cave complex revealed that all of the communities are simple (low-diversity) and dominated by Acidithiobacillus and/or Ferroplasma species, with smaller populations of an Acidimicrobium species, filamentous fungi, and protists. Our results suggest that sulfidic cave snottites will be excellent model microbial ecosystems suited for ecological and metagenomic studies aimed at elucidating geochemical and ecological controls on microbial diversity, and at mapping the spatial history of microbial evolutionary events such as adaptations, recombinations and gene transfers.

  2. Characteristics of the soil microbial population in forest land irrigated with saline water in the desert area

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The study of soil microbial populations and diversity is an important way to understanding the soil energy process.In this study we analyzed the characteristics of soil microbial populations of the Tarim Desert Highway shelter-forest,by identifying microbial fatty acids and using methods of conventional cul-tivation.The results illustrated that the amount of soil microbial activity and the diversity of soil microbial fatty acid increased significantly with the plantation age of the shelter-forest;the soil microbial population was dominated by bacteria.The fatty acids of C14︰0,C15︰0,C16︰0,C17︰0,C18︰1ω9,C18︰0,C18︰2ω6 and C21︰0 were found to be dominant soil microbial fatty acids in the shelter-forest soil.Prin-cipal analysis and regression analysis showed that(1) concentrations of fatty acids of C14︰0,C16︰0 and C18︰0 could be used as indicators of total soil microbial population;(2) soil bacteria and actinomycetes populations were closely correlated with the amount of fatty acids of C15︰0 and C17︰0;and(3) soil fungi were closely correlated with the amount of fatty acids of C18︰1ω9 and C18︰2ω6.

  3. 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

  4. Negative frequency-dependent interactions can underlie phenotypic heterogeneity in a clonal microbial population.

    Science.gov (United States)

    Healey, David; Axelrod, Kevin; Gore, Jeff

    2016-01-01

    Genetically identical cells in microbial populations often exhibit a remarkable degree of phenotypic heterogeneity even in homogenous environments. Such heterogeneity is commonly thought to represent a bet-hedging strategy against environmental uncertainty. However, evolutionary game theory predicts that phenotypic heterogeneity may also be a response to negative frequency-dependent interactions that favor rare phenotypes over common ones. Here we provide experimental evidence for this alternative explanation in the context of the well-studied yeast GAL network. In an environment containing the two sugars glucose and galactose, the yeast GAL network displays stochastic bimodal activation. We show that in this mixed sugar environment, GAL-ON and GAL-OFF phenotypes can each invade the opposite phenotype when rare and that there exists a resulting stable mix of phenotypes. Consistent with theoretical predictions, the resulting stable mix of phenotypes is not necessarily optimal for population growth. We find that the wild-type mixed strategist GAL network can invade populations of both pure strategists while remaining uninvasible by either. Lastly, using laboratory evolution we show that this mixed resource environment can directly drive the de novo evolution of clonal phenotypic heterogeneity from a pure strategist population. Taken together, our results provide experimental evidence that negative frequency-dependent interactions can underlie the phenotypic heterogeneity found in clonal microbial populations. PMID:27487817

  5. Soil-specific limitations for access and analysis of soil microbial communities by metagenomics

    NARCIS (Netherlands)

    Lombard, Nathalie; Prestat, Emmanuel; van Elsas, Jan Dirk; Simonet, Pascal

    2011-01-01

    Metagenomics approaches represent an important way to acquire information on the microbial communities present in complex environments like soil. However, to what extent do these approaches provide us with a true picture of soil microbial diversity? Soil is a challenging environment to work with. It

  6. Soil-specific limitations for access and analysis of soil microbial communities by metagenomics.

    Science.gov (United States)

    Lombard, Nathalie; Prestat, Emmanuel; van Elsas, Jan Dirk; Simonet, Pascal

    2011-10-01

    Metagenomics approaches represent an important way to acquire information on the microbial communities present in complex environments like soil. However, to what extent do these approaches provide us with a true picture of soil microbial diversity? Soil is a challenging environment to work with. Its physicochemical properties affect microbial distributions inside the soil matrix, metagenome extraction and its subsequent analyses. To better understand the bias inherent to soil metagenome 'processing', we focus on soil physicochemical properties and their effects on the perceived bacterial distribution. In the light of this information, each step of soil metagenome processing is then discussed, with an emphasis on strategies for optimal soil sampling. Then, the interaction of cells and DNA with the soil matrix and the consequences for microbial DNA extraction are examined. Soil DNA extraction methods are compared and the veracity of the microbial profiles obtained is discussed. Finally, soil metagenomic sequence analysis and exploitation methods are reviewed.

  7. Improving rumen ecology and microbial population by dried rumen digesta in beef cattle.

    Science.gov (United States)

    Cherdthong, Anusorn; Wanapat, Metha; Saenkamsorn, Anuthida; Supapong, Chanadol; Anantasook, Nirawan; Gunun, Pongsatorn

    2015-06-01

    Four Thai native beef cattle with initial body weight (BW) of 91.8 ± 4.75 kg were randomly assigned according to a 4 × 4 Latin square design to receive four concentrates replacement levels of soybean meal (SBM) by dried rumen digesta (DRD) at 0, 33, 67, and 100 % on dry matter (DM) basis. All cattle were fed rice straw ad libitum while additional concentrate was fed at 0.5 % BW daily. The experiment was conducted for four periods of 21 days. Rumen fluid was analyzed for predominant cellulolytic bacterial population by using real-time PCR technique. Increasing levels of DRD did not alter total feed intake, ruminal pH and temperature, and plasma urea nitrogen (P > 0.05). Protozoa and fungal population were not differed by DRD supplementation while population of bacteria at 4 h post feeding was increased when SBM was replaced with DRD at 66 and 100 % DM. Population of total bacteria and R. flavefaciens at 4 h post feeding were significantly highest with inclusion of 100 % of DRD in the ration. The experimental diets has no effect on excretion and absorption of purine derivatives (P > 0.05), while microbial crude protein and efficiency of microbial N synthesis were significantly increased with DRD inclusion in the diet and highest with 100 % DRD replacement (P > 0.05). Replacement of SBM by DRD at 100 % DM improved the rumen ecology and microbial population in beef cattle fed on rice straw. PMID:25851930

  8. Access to general health care services by a New Zealand population with serious mental illness.

    Directory of Open Access Journals (Sweden)

    Wheeler A

    2014-03-01

    Full Text Available INTRODUCTION: Literature suggests that good quality health care access can have a positive impact on the health of people with serious mental illness (SMI, but literature relating to patterns of access by this group is equivocal. AIM: This study was designed to explore health care access patterns in a group of people with SMI and to compare them with a general New Zealand population group, in order for health providers to understand how they might contribute to positive health outcomes for this group. METHODS: The study surveyed 404 mental health consumers aged 18-65 years receiving care from one district health board in Auckland about their patterns of health care access. Results were compared with those from the New Zealand Health Survey of the general population. RESULTS: Findings suggest that the SMI consumer respondents had poorer physical health than the general population respondents, accessed health care services in more complex ways and were more particular about who they accessed for their care than the general population respondents. There was some concern from SMI consumers around discrimination from health care providers. The study also suggested that some proactive management with SMI consumers for conditions such as metabolic syndrome was occurring within the health care community. DISCUSSION: The first point of access for SMI consumers with general health problems is not always the family general practitioner and so other health professionals may sometimes need to consider the mental and physical health of such consumers in a wider context than their own specialism.

  9. Geochemical Attributes and Gradients Within Geothermal Systems Define the Distribution of Specific Microbial Populations

    Science.gov (United States)

    Inskeep, W. P.; Macur, R. E.; Korf, S.; Taylor, W. P.; Ackerman, G.; Kozubal, M.; Nagy, A.

    2006-12-01

    Microorganisms in natural habitats interact with mineral surfaces in many different respects. For example, microorganisms are known to enhance the dissolution rates of some minerals via the production of organic acids and other exudates, but at the same time, may mineralize solid phases as a direct or indirect result of metabolic processes. It is also well-established that many microorganisms form biofilms on mineral surfaces, and may preferentially attach to surfaces rich in necessary nutrients or in elements used for energy conservation. In part due to the complexity of natural soil, water and sediments systems, it is generally difficult to ascertain mechanisms controlling the distribution of organisms on mineral surfaces and their role in mineral precipitation-dissolution reactions. Geothermal microbial communities are often less diverse than surface soils and sediments and offer opportunities for understanding relationships among specific microbial populations and geochemical processes that define the biogeochemical cycles of individual elements. We have investigated numerous acidic and near-neutral geothermal sites in Yellowstone National Park, and have performed a number of complimentary chemical and microbiological analyses to ascertain the role of microorganisms in S, Fe, As and Sb cycling in geothermal systems. Our results demonstrate the importance of microbiota in the formation of various Fe(III) oxide phases with variable anion chemistry, and the importance of chemolithotrophic metabolisms in Fe, S and As cycling. Where possible, these metabolisms are linked to specific microbial populations identified via molecular methods, and in some cases confirmed using isolation and characterization of individual organisms.

  10. 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 ( cattle fed pulverized and extruded wheat. Ruminal concentrations of total VFA and acetate and the ratio of acetate to propionate decreased ( cattle fed extruded wheat had the lowest concentrations of total VFA and acetate among all treatments. The relative abundance of , , ciliated protozoa, and was lower in cattle fed the pulverized wheat diet than in the other 3 diets ( cattle fed extruded wheat compared with cattle fed crushed and rolled wheat ( 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.

  11. Activity and growth of microbial populations in pressurized deep-sea sediment and animal gut samples.

    Science.gov (United States)

    Tabor, P S; Deming, J W; Ohwada, K; Colwell, R R

    1982-08-01

    Benthic animals and sediment samples were collected at deep-sea stations in the northwest (3,600-m depth) and southeast (4,300- and 5200-m depths) Atlantic Ocean. Utilization rates of [14C]glutamate (0.67 to 0.74 nmol) in sediment suspensions incubated at in situ temperatures and pressures (3 to 5 degrees C and 360, 430, or 520 atmospheres) were relatively slow, ranging from 0.09 to 0.39 nmol g-1 day-1, whereas rates for pressurized samples of gut suspensions varied widely, ranging from no detectable activity to a rapid rate of 986 nmol g-1 day-1. Gut flora from a holothurian specimen and a fish demonstrated rapid, barophilic substrate utilization, based on relative rates calculated for pressurized samples and samples held at 1 atm (101.325 kPa). Substrate utilization by microbial populations in several sediment samples was not inhibited by in situ pressure. Deep-sea pressures did not restrict growth, measured as doubling time, of culturable bacteria present in a northwest Atlantic sediment sample and in a gut suspension prepared from an abyssal scavenging amphipod. From the results of this study, it was concluded that microbial populations in benthic environments can demonstrate significant metabolic activity under deep-ocean conditions of temperature and pressure. Furthermore, rates of microbial activity in the guts of benthic macrofauna are potentially more rapid than in surrounding deep-sea sediments. PMID:6127054

  12. Effects of Flavonoids on Rumen Fermentation Activity, Methane Production, and Microbial Population

    Directory of Open Access Journals (Sweden)

    Ehsan Oskoueian

    2013-01-01

    Full Text Available This research was carried out to evaluate the effects of flavone, myricetin, naringin, catechin, rutin, quercetin, and kaempferol at the concentration of 4.5% of the substrate (dry matter basis on the rumen microbial activity in vitro. Mixture of guinea grass and concentrate (60 : 40 was used as the substrate. The results showed that all the flavonoids except naringin and quercetin significantly ( decreased the dry matter degradability. The gas production significantly ( decreased by flavone, myricetin, and kaempferol, whereas naringin, rutin, and quercetin significantly ( increased the gas production. The flavonoids suppressed methane production significantly (. The total VFA concentration significantly ( decreased in the presence of flavone, myricetin, and kaempferol. All flavonoids except naringin and quercetin significantly ( reduced the carboxymethyl cellulase, filter paperase, xylanase, and β-glucosidase activities, purine content, and the efficiency of microbial protein synthesis. Flavone, myricetin, catechin, rutin, and kaempferol significantly ( reduced the population of rumen microbes. Total populations of protozoa and methanogens were significantly ( suppressed by naringin and quercetin. The results of this research demonstrated that naringin and quercetin at the concentration of 4.5% of the substrate (dry matter basis were potential metabolites to suppress methane production without any negative effects on rumen microbial fermentation.

  13. New methods for analysis of spatial distribution and coaggregation of microbial populations in complex biofilms.

    Science.gov (United States)

    Almstrand, Robert; Daims, Holger; Persson, Frank; Sörensson, Fred; Hermansson, Malte

    2013-10-01

    In biofilms, microbial activities form gradients of substrates and electron acceptors, creating a complex landscape of microhabitats, often resulting in structured localization of the microbial populations present. To understand the dynamic interplay between and within these populations, quantitative measurements and statistical analysis of their localization patterns within the biofilms are necessary, and adequate automated tools for such analyses are needed. We have designed and applied new methods for fluorescence in situ hybridization (FISH) and digital image analysis of directionally dependent (anisotropic) multispecies biofilms. A sequential-FISH approach allowed multiple populations to be detected in a biofilm sample. This was combined with an automated tool for vertical-distribution analysis by generating in silico biofilm slices and the recently developed Inflate algorithm for coaggregation analysis of microbial populations in anisotropic biofilms. As a proof of principle, we show distinct stratification patterns of the ammonia oxidizers Nitrosomonas oligotropha subclusters I and II and the nitrite oxidizer Nitrospira sublineage I in three different types of wastewater biofilms, suggesting niche differentiation between the N. oligotropha subclusters, which could explain their coexistence in the same biofilms. Coaggregation analysis showed that N. oligotropha subcluster II aggregated closer to Nitrospira than did N. oligotropha subcluster I in a pilot plant nitrifying trickling filter (NTF) and a moving-bed biofilm reactor (MBBR), but not in a full-scale NTF, indicating important ecophysiological differences between these phylogenetically closely related subclusters. By using high-resolution quantitative methods applicable to any multispecies biofilm in general, the ecological interactions of these complex ecosystems can be understood in more detail.

  14. Accessing the population of high redshift Gamma Ray Bursts

    CERN Document Server

    Ghirlanda, G; Ghisellini, G; Mereghetti, S; Tagliaferri, G; Campana, S; Osborne, J P; O'Brien, P; Tanvir, N; Willingale, R; Amati, L; Basa, S; Bernardini, M G; Burlon, D; Covino, S; D'Avanzo, P; Frontera, F; Gotz, D; Melandri, A; Nava, L; Piro, L; Vergani, S D

    2015-01-01

    Gamma Ray Bursts (GRBs) are a powerful probe of the high redshift Universe. We present a tool to estimate the detection rate of high-z GRBs by a generic detector with defined energy band and sensitivity. We base this on a population model that reproduces the observed properties of GRBs detected by Swift, Fermi and CGRO in the hard X-ray and gamma-ray bands. We provide the expected cumulative distributions of the flux and fluence of simulated GRBs in different energy bands. We show that scintillator detectors, operating at relatively high energies (e.g. tens of keV to the MeV), can detect only the most luminous GRBs at high redshifts due to the link between the peak spectral energy and the luminosity (Ep-Liso) of GRBs. We show that the best strategy for catching the largest number of high-z bursts is to go softer (e.g. in the soft X-ray band) but with a very high sensitivity. For instance, an imaging soft X-ray detector operating in the 0.2-5 keV energy band reaching a sensitivity, corresponding to a fluence o...

  15. Quantitative Modeling of Microbial Population Responses to Chronic Irradiation Combined with Other Stressors.

    Directory of Open Access Journals (Sweden)

    Igor Shuryak

    Full Text Available Microbial population responses to combined effects of chronic irradiation and other stressors (chemical contaminants, other sub-optimal conditions are important for ecosystem functioning and bioremediation in radionuclide-contaminated areas. Quantitative mathematical modeling can improve our understanding of these phenomena. To identify general patterns of microbial responses to multiple stressors in radioactive environments, we analyzed three data sets on: (1 bacteria isolated from soil contaminated by nuclear waste at the Hanford site (USA; (2 fungi isolated from the Chernobyl nuclear-power plant (Ukraine buildings after the accident; (3 yeast subjected to continuous γ-irradiation in the laboratory, where radiation dose rate and cell removal rate were independently varied. We applied generalized linear mixed-effects models to describe the first two data sets, whereas the third data set was amenable to mechanistic modeling using differential equations. Machine learning and information-theoretic approaches were used to select the best-supported formalism(s among biologically-plausible alternatives. Our analysis suggests the following: (1 Both radionuclides and co-occurring chemical contaminants (e.g. NO2 are important for explaining microbial responses to radioactive contamination. (2 Radionuclides may produce non-monotonic dose responses: stimulation of microbial growth at low concentrations vs. inhibition at higher ones. (3 The extinction-defining critical radiation dose rate is dramatically lowered by additional stressors. (4 Reproduction suppression by radiation can be more important for determining the critical dose rate, than radiation-induced cell mortality. In conclusion, the modeling approaches used here on three diverse data sets provide insight into explaining and predicting multi-stressor effects on microbial communities: (1 the most severe effects (e.g. extinction on microbial populations may occur when unfavorable environmental

  16. Quantitative Modeling of Microbial Population Responses to Chronic Irradiation Combined with Other Stressors.

    Science.gov (United States)

    Shuryak, Igor; Dadachova, Ekaterina

    2016-01-01

    Microbial population responses to combined effects of chronic irradiation and other stressors (chemical contaminants, other sub-optimal conditions) are important for ecosystem functioning and bioremediation in radionuclide-contaminated areas. Quantitative mathematical modeling can improve our understanding of these phenomena. To identify general patterns of microbial responses to multiple stressors in radioactive environments, we analyzed three data sets on: (1) bacteria isolated from soil contaminated by nuclear waste at the Hanford site (USA); (2) fungi isolated from the Chernobyl nuclear-power plant (Ukraine) buildings after the accident; (3) yeast subjected to continuous γ-irradiation in the laboratory, where radiation dose rate and cell removal rate were independently varied. We applied generalized linear mixed-effects models to describe the first two data sets, whereas the third data set was amenable to mechanistic modeling using differential equations. Machine learning and information-theoretic approaches were used to select the best-supported formalism(s) among biologically-plausible alternatives. Our analysis suggests the following: (1) Both radionuclides and co-occurring chemical contaminants (e.g. NO2) are important for explaining microbial responses to radioactive contamination. (2) Radionuclides may produce non-monotonic dose responses: stimulation of microbial growth at low concentrations vs. inhibition at higher ones. (3) The extinction-defining critical radiation dose rate is dramatically lowered by additional stressors. (4) Reproduction suppression by radiation can be more important for determining the critical dose rate, than radiation-induced cell mortality. In conclusion, the modeling approaches used here on three diverse data sets provide insight into explaining and predicting multi-stressor effects on microbial communities: (1) the most severe effects (e.g. extinction) on microbial populations may occur when unfavorable environmental

  17. Molecular Analysis of Dominant Microbial Populations in Heavily and Slightly Polluted Aquifers by a Seaside Landfill

    Institute of Scientific and Technical Information of China (English)

    TIAN Yangjie; YANG Hong; LI Daotang; WU Xiujuan

    2005-01-01

    The microbial populations were investigated in two groundwater samples, GW-H and GW-S, which represented heavily and slightly polluted aquifers by a seaside landfill. The concentrations of dissolved redox-relevant species suggested that iron-reduction/sulfate-reduction and denitrification were major redox processes for GW-H and GW-S. The dominant microbial populations were determined using restriction fragment length polymorphism analyses of 16S rRNA gene clone libraries. These microbes were then further studied by sequencing and phylogenetic analyses. The results indicate an obvious variation of the dominant populations between the two samples. The coexistence of sequences related to denitrifiers, sulfur-reducers, and methanotrophic bacteria was found in the GW-S sample, and a sequence associated with a sulfate-reducer was also found in the GW-H sample using molecular analyses. These results suggest that the molecular approach may be an important supplement to other approaches in characterizing the redox processes in polluted aquifers.

  18. Biodegradation of trichloroethylene and toluene by indigenous microbial populations in soil.

    OpenAIRE

    S. Fan; Scow, K.M.

    1993-01-01

    The biodegradation of trichloroethylene (TCE) and toluene, incubated separately and in combination, by indigenous microbial populations was measured in three unsaturated soils incubated under aerobic conditions. Sorption and desorption of TCE (0.1 to 10 micrograms ml-1) and toluene (1.0 to 20 micrograms ml-1) were measured in two soils and followed a reversible linear isotherm. At a concentration of 1 micrograms ml-1, TCE was not degraded in the absence of toluene in any of the soils. In comb...

  19. The Effect of Microbial Population and Bioregeneration of used GAC in an Activated Sludge Reactor

    Directory of Open Access Journals (Sweden)

    SAEED REZA ASEMI

    2012-12-01

    Full Text Available In the present work an attempt is made to study the role of microbial population on bioregenerationof granular activated carbon (GAC loaded with phenol compounds in continues bioreactor. The GAC used to treat industrial wastewater of the Mobarakeh steel factory (Esfahan-Iran, is regenerated by means of biological method. Industrial microbes that obtained from the chemical wastewater treatment unit (in the Mobarakeh steel factory, were used in the bioregeneration process of activated carbon. The relationships between each two important parameters of bioregeneration such as adsorbed phenol, pH, mixed liquor suspended solids (MLSS, total suspended solids (TSS and sludge volume index (SVI were studied. It was observed that the adsorption capacity of the bioregenerated GAC increased during the two months of bioregeneration. Furthermore, it was found that pH gradually decreased with degradation of chemical compounds within pores of used GAC. The phenol adsorption capacity increased with increasing microbial cells concentration. In addition, the sludge volume index (SVI decreased from around 231.11 mL mg1*, to 32.68 mL mg-1 during two months of bioregeneration of used GAC. While microbial concentration increases during thebioregeneration process in continues bioreactor.

  20. Assessment of microbial populations in methyl ethyl ketone degrading biofilters by denaturing gradient gel electrophoresis.

    Science.gov (United States)

    Li, C; Moe, W M

    2004-05-01

    Denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction-amplified genes coding for 16S rRNA was used to assess differences in bacterial community structure as a function of spatial location along the height of two biofilters used to treat a model waste gas stream containing methyl ethyl ketone (MEK). One of the laboratory-scale biofilters was operated as a conventional continuous-flow biofilter (CFB) and the other was operated as a sequencing batch biofilter (SBB). Both biofilters, inoculated with an identical starting culture and operated over a period lasting more than 300 days, received the same influent MEK concentration and same mass of MEK on a daily basis. The systems differed, however, in terms of the fraction of time during which contaminated air was supplied and the overall operating strategy employed. DGGE analysis indicated that microbial community structures differed as a function of height in each of the biofilters. The DGGE banding patterns also differed between the two biofilters, suggesting that operating strategies imposed on the biofilters imparted a sufficiently large selective pressure to influence microbial community structures. This may explain, in part, the superior performance of the SBB over the CFB during model transient loading conditions, and it may open new possibilities for purposely manipulating the microbial populations in biofilters treating gas-phase contaminants in a manner that leads to more favorable treatment performance.

  1. SPSmart: adapting population based SNP genotype databases for fast and comprehensive web access

    Directory of Open Access Journals (Sweden)

    Carracedo Ángel

    2008-10-01

    Full Text Available Abstract Background In the last five years large online resources of human variability have appeared, notably HapMap, Perlegen and the CEPH foundation. These databases of genotypes with population information act as catalogues of human diversity, and are widely used as reference sources for population genetics studies. Although many useful conclusions may be extracted by querying databases individually, the lack of flexibility for combining data from within and between each database does not allow the calculation of key population variability statistics. Results We have developed a novel tool for accessing and combining large-scale genomic databases of single nucleotide polymorphisms (SNPs in widespread use in human population genetics: SPSmart (SNPs for Population Studies. A fast pipeline creates and maintains a data mart from the most commonly accessed databases of genotypes containing population information: data is mined, summarized into the standard statistical reference indices, and stored into a relational database that currently handles as many as 4 × 109 genotypes and that can be easily extended to new database initiatives. We have also built a web interface to the data mart that allows the browsing of underlying data indexed by population and the combining of populations, allowing intuitive and straightforward comparison of population groups. All the information served is optimized for web display, and most of the computations are already pre-processed in the data mart to speed up the data browsing and any computational treatment requested. Conclusion In practice, SPSmart allows populations to be combined into user-defined groups, while multiple databases can be accessed and compared in a few simple steps from a single query. It performs the queries rapidly and gives straightforward graphical summaries of SNP population variability through visual inspection of allele frequencies outlined in standard pie-chart format. In addition, full

  2. 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. PMID:17995650

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

    International Nuclear Information System (INIS)

    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

  4. 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...... and flagellates) were often seen attached to the microcolonies. The biofilm was hybridized with oligonucleotide probes specific for all bacteria and the α- and β-subclass of Proteobacteria and visualized with a scanning confocal laser microscope. Hybridization showed that the microcolonies primarily consisted...... 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...

  5. Root Zone Microbial Populations, Urease Activities, and Purification Efficiency for a Constructed Wetland

    Institute of Scientific and Technical Information of China (English)

    LIANG Wei; WU Zhen-Bin; ZHAN Fa-Cui; DENG Jia-Qi

    2004-01-01

    In order to investigate the effects of microorganisms and their urease activities in macrophytic root zones on pollutant removal, four small-scale plots (SSPs) of vertical/reverse-vertical flow wetlands were set up to determine: a) the relationship between the abundance of microorganisms in the root zones and water purification efficiency; and b) the relationship between urease activities in the root zones and pollutant removal in a constructed wetland system. Total numbers of the microbial population (bacteria, fungi, and actinomyces) along with urease activities in the macrophytic root zones were determined. In addition, the relationships between microbial populations and urease activities as well as the wastewater purification efficiencies of total phosphorus (TP), total Kjeldahl nitrogen (TKN), biochemical oxygen demand in 5 days (BOD5), and chemical oxygen demand (COD) were also analyzed. The results showed that there was a highly significant positive correlation (r = 0.9772, P < 0.01) between the number of bacteria in the root zones and BOD5 removal efficiency and a significant negative correlation (r = -0.9092, P < 0.05) between the number of fungi and the removal efficiency of TKN. Meanwhile, there was a significant positive correlation (r -- 0.8830, P < 0.05) between urease activities in the root zones and the removal efficiency of TKN. Thus, during wastewater treatment in a constructed wetland system,microorganism and urease activities in the root zones were very important factors.

  6. Effects of methane on the microbial populations and oxidation rates in different landfill cover soil columns.

    Science.gov (United States)

    He, Ruo; Ruan, Aidong; Shen, Dong-Sheng

    2007-05-01

    A considerable fraction of methane produced in landfills is oxidized by landfill cover soils. In this work, microbial populations and oxidation rates developed in response to the presence of methane were studied in three soil columns simulated landfill cover soil environments. The population of aerobic heterotrophic bacteria was highest in the waste soil, middle in the clay soil, and lowest in the red soil. After exposure to methane-rich environments, the populations of methanotrophic bacteria showed increases in the waste and clay soils. The population of methanotrophic bacteria increased from 30.77x10(4) to 141.77x10(4) cfu g d.w.-1 in the middle layer of the waste soil column as a function of exposure to methane for 120 days. The populations of methanotrophic bacteria were correlated with the potential methane oxidation rates in the waste and clay soils, respectively. The topsoil was observed to be dried in the three soil columns. Most of methane oxidation occurred at the depth of between 10 and 20 cm in the waste soil column, while it took place mainly at the depth of between 20 and 30 cm in the clay soil column.

  7. Microbial Population Differentials between Mucosal and Submucosal Intestinal Tissues in Advanced Crohn's Disease of the Ileum.

    Directory of Open Access Journals (Sweden)

    Rodrick J Chiodini

    Full Text Available Since Crohn's disease is a transmural disease, we hypothesized that examination of deep submucosal tissues directly involved in the inflammatory disease process may provide unique insights into bacterial populations transgressing intestinal barriers and bacterial populations more representative of the causes and agents of the disease. We performed deep 16s microbiota sequencing on isolated ilea mucosal and submucosal tissues on 20 patients with Crohn's disease and 15 non-inflammatory bowel disease controls with a depth of coverage averaging 81,500 sequences in each of the 70 DNA samples yielding an overall resolution down to 0.0001% of the bacterial population. Of the 4,802,328 total sequences generated, 98.9% or 4,749,183 sequences aligned with the Kingdom Bacteria that clustered into 8545 unique sequences with <3% divergence or operational taxonomic units enabling the identification of 401 genera and 698 tentative bacterial species. There were significant differences in all taxonomic levels between the submucosal microbiota in Crohn's disease compared to controls, including organisms of the Order Desulfovibrionales that were present within the submucosal tissues of most Crohn's disease patients but absent in the control group. A variety of organisms of the Phylum Firmicutes were increased in the subjacent submucosa as compared to the parallel mucosal tissue including Ruminococcus spp., Oscillospira spp., Pseudobutyrivibrio spp., and Tumebacillus spp. In addition, Propionibacterium spp. and Cloacibacterium spp. were increased as well as large increases in Proteobacteria including Parasutterella spp. and Methylobacterium spp. This is the first study to examine the microbial populations within submucosal tissues of patients with Crohn's disease and to compare microbial communities found deep within the submucosal tissues with those present on mucosal surfaces. Our data demonstrate the existence of a distinct submucosal microbiome and ecosystem

  8. Genetic diversity and population structure of Korean and Chinese soybean [Glycine max (L.) Merr.] accessions

    Science.gov (United States)

    Korean and Chinese cultivated soybean [Glycine max (L.) Merr.] populations are major soybean gene pools. Information has been reported comparing genetic diversity between soybeans from the two countries using an unequal number of accessions and only 6 to 35 genetic markers. This study compares diffe...

  9. Soil Bacteria Population Dynamics Following Stimulation for Ureolytic Microbial-Induced CaCO3 Precipitation.

    Science.gov (United States)

    Gat, Daniella; Ronen, Zeev; Tsesarsky, Michael

    2016-01-19

    Microbial-induced CaCO3 precipitation (MICP) via urea-hydrolysis (ureolysis) is an emerging soil improvement technique for various civil engineering and environmental applications. In-situ application of MICP in soils is performed either by augmenting the site with ureolytic bacteria or by stimulating indigenous ureolytic bacteria. Both of these approaches may lead to changes in the indigenous bacterial population composition and to the accumulation of large quantities of ammonium. In this batch study, effective ureolysis was stimulated in coastal sand from a semiarid environment, with low initial ureolytic bacteria abundance. Two different carbon sources were used: yeast-extract and molasses. No ureolysis was observed in their absence. Ureolysis was achieved using both carbon sources, with a higher rate in the yeast-extract enrichment resulting from increased bacterial growth. The changes to the indigenous bacterial population following biostimulation of ureolysis were significant: Bacilli class abundancy increased from 5% in the native sand up to 99% in the yeast-extract treatment. The sand was also enriched with ammonium-chloride, where ammonia-oxidation was observed after 27 days, but was not reflected in the bacterial population composition. These results suggest that biostimulation of ureolytic bacteria can be applied even in a semiarid and nutrient-poor environment using a simple carbon source, that is, molasses. The significant changes to bacterial population composition following ureolysis stimulation could result in a decrease in trophic activity and diversity in the treated site, thus they require further attention. PMID:26689904

  10. Distribution of Microbial Populations and Their Relationship with Environmental Variables in the North Yellow Sea, China

    Institute of Scientific and Technical Information of China (English)

    BAI Xiaoge; WANG Min; LIANG Yantao; ZHANG Zhifeng; WANG Fang; JIANG Xuejiao

    2012-01-01

    In order to understand the large-scale spatial distribution characteristics of picoplankton,nanophytoplankton and vireoplankton 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 10m 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.

  11. Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils.

    Science.gov (United States)

    Leung, Hilary T C; Maas, Kendra R; Wilhelm, Roland C; Mohn, William W

    2016-02-01

    Forest ecosystems need to be sustainably managed, as they are major reservoirs of biodiversity, provide important economic resources and modulate global climate. We have a poor knowledge of populations responsible for key biomass degradation processes in forest soils and the effects of forest harvesting on these populations. Here, we investigated the effects of three timber-harvesting methods, varying in the degree of organic matter removal, on putatively hemicellulolytic bacterial and fungal populations 10 or more years after harvesting and replanting. We used stable-isotope probing to identify populations that incorporated (13)C from labeled hemicellulose, analyzing (13)C-enriched phospholipid fatty acids, bacterial 16 S rRNA genes and fungal ITS regions. In soil microcosms, we identified 104 bacterial and 52 fungal hemicellulolytic operational taxonomic units (OTUs). Several of these OTUs are affiliated with taxa not previously reported to degrade hemicellulose, including the bacterial genera Methylibium, Pelomonas and Rhodoferax, and the fungal genera Cladosporium, Pseudeurotiaceae, Capronia, Xenopolyscytalum and Venturia. The effect of harvesting on hemicellulolytic populations was evaluated based on in situ bacterial and fungal OTUs. Harvesting treatments had significant but modest long-term effects on relative abundances of hemicellulolytic populations, which differed in strength between two ecozones and between soil layers. For soils incubated in microcosms, prior harvesting treatments did not affect the rate of incorporation of hemicellulose carbon into microbial biomass. In six ecozones across North America, distributions of the bacterial hemicellulolytic OTUs were similar, whereas distributions of fungal ones differed. Our work demonstrates that diverse taxa in soil are hemicellulolytic, many of which are differentially affected by the impact of harvesting on environmental conditions. However, the hemicellulolytic capacity of soil communities appears

  12. [Factors affecting access to health care institutions by the internally displaced population in Colombia].

    Science.gov (United States)

    Mogollón-Pérez, Amparo Susana; Vázquez, María Luisa

    2008-04-01

    In Colombia, the on-going armed conflict causes displacement of thousands of persons that suffer its economic, social, and health consequences. Despite government regulatory efforts, displaced people still experience serious problems in securing access to health care. In order to analyze the institutional factors that affect access to health care by the internally displaced population, a qualitative, exploratory, and descriptive study was carried out by means of semi-structured individual interviews with a criterion sample of stakeholders (81). A narrative content analysis was performed, with mixed generation of categories and segmentation of data by themes and informants. Inadequate funding, providers' problems with reimbursement by insurers, and lack of clear definition as to coverage under the Social Security System in Health pose barriers to access to health care by the internally displaced population. Bureaucratic procedures, limited inter- and intra-sector coordination, and scarce available resources for public health service providers also affect access. Effective government action is required to ensure the right to health care for this population. PMID:18392351

  13. Ecological differentiation in planktonic and sediment-associated chemotrophic microbial populations in Yellowstone hot springs.

    Science.gov (United States)

    Colman, Daniel R; Feyhl-Buska, Jayme; Robinson, Kirtland J; Fecteau, Kristopher M; Xu, Huifang; Shock, Everett L; Boyd, Eric S

    2016-09-01

    Chemosynthetic sediment and planktonic community composition and sizes, aqueous geochemistry and sediment mineralogy were determined in 15 non-photosynthetic hot springs in Yellowstone National Park (YNP). These data were used to evaluate the hypothesis that differences in the availability of dissolved or mineral substrates in the bulk fluids or sediments within springs coincides with ecologically differentiated microbial communities and their populations. Planktonic and sediment-associated communities exhibited differing ecological characteristics including community sizes, evenness and richness. pH and temperature influenced microbial community composition among springs, but within-spring partitioning of taxa into sediment or planktonic communities was widespread, statistically supported (P < 0.05) and could be best explained by the inferred metabolic strategies of the partitioned taxa. Microaerophilic genera of the Aquificales predominated in many of the planktonic communities. In contrast, taxa capable of mineral-based metabolism such as S(o) oxidation/reduction or Fe-oxide reduction predominated in sediment communities. These results indicate that ecological differentiation within thermal spring habitats is common across a range of spring geochemistry and is influenced by the availability of dissolved nutrients and minerals that can be used in metabolism.

  14. 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.

  15. Ecological differentiation in planktonic and sediment-associated chemotrophic microbial populations in Yellowstone hot springs.

    Science.gov (United States)

    Colman, Daniel R; Feyhl-Buska, Jayme; Robinson, Kirtland J; Fecteau, Kristopher M; Xu, Huifang; Shock, Everett L; Boyd, Eric S

    2016-09-01

    Chemosynthetic sediment and planktonic community composition and sizes, aqueous geochemistry and sediment mineralogy were determined in 15 non-photosynthetic hot springs in Yellowstone National Park (YNP). These data were used to evaluate the hypothesis that differences in the availability of dissolved or mineral substrates in the bulk fluids or sediments within springs coincides with ecologically differentiated microbial communities and their populations. Planktonic and sediment-associated communities exhibited differing ecological characteristics including community sizes, evenness and richness. pH and temperature influenced microbial community composition among springs, but within-spring partitioning of taxa into sediment or planktonic communities was widespread, statistically supported (P < 0.05) and could be best explained by the inferred metabolic strategies of the partitioned taxa. Microaerophilic genera of the Aquificales predominated in many of the planktonic communities. In contrast, taxa capable of mineral-based metabolism such as S(o) oxidation/reduction or Fe-oxide reduction predominated in sediment communities. These results indicate that ecological differentiation within thermal spring habitats is common across a range of spring geochemistry and is influenced by the availability of dissolved nutrients and minerals that can be used in metabolism. PMID:27306555

  16. Visualizing the population dynamics of microbial communities in the larval zebrafish gut

    Science.gov (United States)

    Parthasarathy, Raghuveer

    In each of our digestive tracts, trillions of microbes representing hundreds of different species colonize local environments, reproduce, and compete with one another. The resulting ecosystems influence many aspects their host's development and health. Little is known about how gut microbial communities vary in space and time: how they grow, fluctuate, and respond to various perturbations. To address this and investigate microbial colonization of the vertebrate gut, we apply light sheet fluorescence microscopy to a model system that combines a realistic in vivo environment with a high degree of experimental control: larval zebrafish with defined subsets of commensal bacterial species. Light sheet microscopy enables three-dimensional imaging with high resolution over the entire intestine, providing visualizations that would be difficult or impossible to achieve with other techniques. Quantitative analysis of image data enables measurement of bacterial abundances and distributions. I will describe this approach and focus especially on recent experiments in which a colonizing bacterial species is challenged by the invasion of a second species, which leads to the decline of the first group. Imaging reveals dramatic population collapses that differentially affect the two species due to their different biogeographies and morphologies. The collapses are driven by the peristaltic motion of the zebrafish intestine, indicating that the physical activity of the host environment can play a major role in mediating inter-species competition. role in mediating inter-species competition. Supported by the National Science Foundation under Grant No. 0922951 and the National Institutes of Health under Award Number 1P50GM098911.

  17. Spatial analysis of cattle and shoat population in Ethiopia: growth trend, distribution and market access.

    Science.gov (United States)

    Leta, Samson; Mesele, Frehiwot

    2014-01-01

    The livestock subsector has an enormous contribution to Ethiopia's national economy and livelihoods of many Ethiopians. The subsector contributes about 16.5% of the national Gross Domestic Product (GDP) and 35.6% of the agricultural GDP. It also contributes 15% of export earnings and 30% of agricultural employment. The livestock subsector currently support and sustain livelihoods for 80% of all rural population. The GDP of livestock related activities valued at 59 billion birr. Ethiopian livestock population trends, distribution and marketing vary considerably across space and time due to a variety of reasons. This study was aimed to assess cattle and shoat population growth trend, distribution and their access to market. Regression analysis was used to assess the cattle and shoat population growth trend and Geographic Information Systems (GIS) techniques were used to determine the spatial distribution of cattle and shoats, and their relative access to market. The data sets used are agricultural census (2001/02) and annual CSA agricultural sample survey (1995/96 to 2012/13). In the past eighteen years, the livestock population namely cattle, sheep and goat grew from 54.5 million to over 103.5 million with average annual increment of 3.4 million. The current average national cattle, sheep and goat population per km(2) are estimated to be 71, 33 and 29 respectively (excluding Addis Ababa, Afar and Somali regions). From the total livestock population the country owns about 46% cattle, 43% sheep and 40% goats are reared within 10 km radius from major livestock market centres and all-weather roads. On the other hand, three fourth of the country's land mass which comprises 15% of the cattle, 20% of the sheep and 21% of goat population is not accessible to market (greater than 30 km from major livestock market centres). It is found that the central highland regions account for the largest share of livestock population and also more accessible to market. Defining the

  18. Microbial population, activity, and phylogenetic diversity in the subseafloor core sediment from the Sea of Okhotsk

    Science.gov (United States)

    Inagaki, F.; Suzuki, M.; Takai, K.; Nealson, K. H.; Horikoshi, K.

    2002-12-01

    Subseafloor environments has already been recognized as the largest biosphere on the planet Earth, however, the microbial diversity and activity has been still poorly understood, even in their impacts on biogeochemical processes, tectonic settings, and paleoenvironmental events. We demonstrate here the evaluation of microbial community structure and active habitats in deeply buried cold marine sediments collected from the Sea of Okhotsk by a combined use of molecular ecological surveys and culturing assays. The piston core sediment (MD01-2412) was collected by IMAGES (International Marine Global Change Study) Project from the southeastern Okhotsk Sea, June 2001. The total recovered length was about 58m. The lithology of the core sediment was mainly constructed from pelagic clay (PC) and volcanic ash layers (Ash). We collected aseptically the most inside core parts from 16 sections at different depths for microbiological study. The direct count of DAPI-stained cells revealed that the cells in Ash samples were present 1.2 to 2.2 times higher than in PC samples. The quantitative-PCR of 16S rDNA between bacterial and archaeal rDNA suggested that the increased population density in Ash layers was caused by the bacterial components. We studied approximately 650 and 550 sequences from bacterial and archaeal rDNA clone libraries, respectively. The similarity and phylogenetic analyses revealed that the microbial community structures were apparently different between in Ash layers and PC samples. From bacterial rDNA clone libraries, the members within gamma-Proteobacteria such as genera Halomonas, Shewanella, Psychromonas and Methylosinus were predominantly detected in Ash layers whereas the Dehalococcoides group and delta-Proteobacteria were major bacterial components in PC samples. From archaeal libraries, the sequences from Ash and PC samples were affiliated into the clusters represented by the environmental sequences obtained from terrestrial and deep-sea environments

  19. Survey of microbial populations within Lake Michigan nearshore waters at two Chicago public beaches.

    Science.gov (United States)

    Malki, Kema; Bruder, Katherine; Putonti, Catherine

    2015-12-01

    Lake Michigan is a critical resource for the residents of Chicago, providing drinking water to its 9+ million area residents. Along Chicago׳s 26 miles of public beaches the populous urban environment and this freshwater environment meet. While city-led monitoring initiatives investigate pathogenic bacteria in these nearshore waters, very little is known about other microbial species present. We collected surface water samples from two Chicago public beaches - Montrose Beach and 57th Street Beach - every ten days from June 5 through August 4, 2013 as well as once in early Fall (October 4, 2013). Sixteen bacterial communities in total were surveyed through targeted sequencing of the V4 16S rRNA gene. Taxa were identified using Mothur. Raw sequence data is available via NCBI׳s SRA database (part of BioProject PRJNA245802). OTU calls for each read are also available at our online repository: www.lakemichiganmicrobes.com/bacteria/. PMID:26958608

  20. Microbial population dynamics during sludge granulation in an A/O/A sequencing batch reactor.

    Science.gov (United States)

    He, Qiulai; Zhou, Jun; Wang, Hongyu; Zhang, Jing; Wei, Li

    2016-08-01

    The evolution of the bacterial population during formation of denitrifying phosphorus removal granular sludge was investigated using high-throughput pyrosequencing. As a result, mature granules with a compact structure were obtained in an anaerobic/aerobic/anoxic (A/O/A) sequencing batch reactor under an organic loading rate as low as 0.3kg COD/(m(3)·d). Rod-shaped microbes were observed to cover with the outer surface of granules. Besides, reliable COD and simultaneous nitrogen and phosphorus removal efficiencies were achieved over the whole operation period. MiSeq pyrosequencing analysis illustrated that both the microbial diversity and richness increased sharply during the granulation process, whereas they stayed stable after the presence of granules. Some microorganisms seemed to contribute to the formation of granules, and some were identified as functional bacterial groups responsible for constructing the biological reactor. PMID:27115745

  1. Demographic population model for American shad: will access to additional habitat upstream of dams increase population sizes?

    Science.gov (United States)

    Harris, Julianne E.; Hightower, Joseph E.

    2012-01-01

    American shad Alosa sapidissima are in decline in their native range, and modeling possible management scenarios could help guide their restoration. We developed a density-dependent, deterministic, stage-based matrix model to predict the population-level results of transporting American shad to suitable spawning habitat upstream of dams on the Roanoke River, North Carolina and Virginia. We used data on sonic-tagged adult American shad and oxytetracycline-marked American shad fry both above and below dams on the Roanoke River with information from other systems to estimate a starting population size and vital rates. We modeled the adult female population over 30 years under plausible scenarios of adult transport, effective fecundity (egg production), and survival of adults (i.e., to return to spawn the next year) and juveniles (from spawned egg to age 1). We also evaluated the potential effects of increased survival for adults and juveniles. The adult female population size in the Roanoke River was estimated to be 5,224. With no transport, the model predicted a slow population increase over the next 30 years. Predicted population increases were highest when survival was improved during the first year of life. Transport was predicted to benefit the population only if high rates of effective fecundity and juvenile survival could be achieved. Currently, transported adults and young are less likely to successfully out-migrate than individuals below the dams, and the estimated adult population size is much smaller than either of two assumed values of carrying capacity for the lower river; therefore, transport is not predicted to help restore the stock under present conditions. Research on survival rates, density-dependent processes, and the impacts of structures to increase out-migration success would improve evaluation of the potential benefits of access to additional spawning habitat for American shad.

  2. Linking TFT-LCD wastewater treatment performance to microbial population abundance of Hyphomicrobium and Thiobacillus spp.

    Science.gov (United States)

    Fukushima, Toshikazu; Whang, Liang-Ming; Chen, Po-Chun; Putri, Dyah Wulandari; Chang, Ming-Yu; Wu, Yi-Ju; Lee, Ya-Ching

    2013-08-01

    This study investigated the linkage between performance of two full-scale membrane bioreactor (MBR) systems treating thin-film transistor liquid crystal display (TFT-LCD) wastewater and the population dynamics of dimethylsulfoxide (DMSO)/dimethylsulfide (DMS) degrading bacteria. High DMSO degradation efficiencies were achieved in both MBRs, while the levels of nitrification inhibition due to DMS production from DMSO degradation were different in the two MBRs. The results of real-time PCR targeting on DMSO/DMS degrading populations, including Hyphomicrobium and Thiobacillus spp., indicated that a higher DMSO oxidation efficiency occurred at a higher Hyphomicrobium spp. abundance in the systems, suggesting that Hyphomicrobium spp. may be more important for complete DMSO oxidation to sulfate compared with Thiobacillus spp. Furthermore, Thiobacillus spp. was more abundant during poor nitrification, while Hyphomicrobium spp. was more abundant during good nitrification. It is suggested that microbial population of DMSO/DMS degrading bacteria is closely linking to both DMSO/DMS degradation efficiency and nitrification performance.

  3. 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.

  4. Effect of wastewater COD/N ratio on aerobic nitrifying sludge granulation and microbial population shift

    Institute of Scientific and Technical Information of China (English)

    Lei Wu; Chengyao Peng; Yongzhen Peng; Lingyun Li; Shuying Wang; Yong Ma

    2012-01-01

    The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200 (m/n).Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/(mg MLVSS.hr),respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.

  5. MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process.

    Science.gov (United States)

    Araujo, Pablo Granda; Gras, Anna; Ginovart, Marta

    2016-01-01

    Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs) using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics) can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4 (+), NO3 (-), NO2 (-), N2) to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc). MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

  6. MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process.

    Science.gov (United States)

    Araujo, Pablo Granda; Gras, Anna; Ginovart, Marta

    2016-01-01

    Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs) using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics) can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4 (+), NO3 (-), NO2 (-), N2) to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc). MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience. PMID:27635191

  7. Molecular characterization of microbial populations in full-scale biofilters treating iron, manganese and ammonia containing groundwater in Harbin, China.

    Science.gov (United States)

    Li, Xiang-kun; Chu, Zhao-rui; Liu, Ya-jun; Zhu, Meng-ting; Yang, Liu; Zhang, Jie

    2013-11-01

    In iron and manganese-containing groundwater treatment for drinking water production, biological filter is an effective process to remove such pollutants. Until now the exact microbial mechanism of iron and manganese removal, especially coupled with other pollutants, such as ammonia, has not been clearly understood. To assess this issue, the performance of a full-scale biofilter located in Harbin, China was monitored over four months. Microbial populations in the biofilter were investigated using T-RFLP and clone library technique. Results suggested that Gallionella, Leptothrix, Nitrospira, Hyphomicrobium and Pseudomonas are dominant in the biofilter and play major roles in the removal of iron, manganese and ammonia. The spatial distribution of microbial populations along the depth of the biofilter demonstrated the stratification of the removal of iron, manganese and ammonia. Additionally, the absence of ammonia-oxidizing bacteria in the biofilter implicated that ammonia-oxidizing archaea might be responsible for the oxidation of ammonia to nitrite.

  8. Microbial populations of an upflow anaerobic sludge blanket reactor treating wastewater from a gelatin industry.

    Science.gov (United States)

    Vieira, A M; Bergamasco, R; Gimenes, M L; Nakamura, C V; Dias Filho, B P

    2001-12-01

    The microbial populations of an upflow anaerobic sludge blanket reactor, used for treating wastewater from the gelatin industry, were studied by microbiological methods and phase-contrast and electron microscopy. Microscopy examination of the sludge showed a complex mixture of various rod-shaped and coccoid bacterial pluslong filaments and verymobile curved rods. In addition free-living anaerobic ciliates and flagellates were also observed. The trophic group population observed in decreasing order of dominance were hydrolytic and acetogenic at 10(6) and sulfate reducing and methanogenic at 10(5). The rate of methane production in anaerobic granular sludge cultivated in growth medium supplement with formate pressurized with H2:CO2 showed a significant increase in methane yield compared with theseed culture containingthe same substrate and atmosphere of N2:CO2. Similar rates of methane production were observed when the growth medium was supplemented with acetate pressurized either with H2:CO2 or N2:CO2. The number of total anaerobic bacteria at 10(7), fecal coliforms and total coliforms at 10(6), and fecal streptococci at 10(3) is based on colony counts on solid media. The four prevalent species of facultative anaerobic gram-negative bacteria that belong to the family of Enterobacteriaceae were identified as Escherichia coli, Esherichia fergusonii, Klebsiella oxytoca, and Citrobacter freundii. The species Aeromonas hydrophila, Aeromonas veronii, Acinetobacter iwoffi and Stenotrophomonas maltophila were the most frequently isolated glucose fermenting and nonfermenting gram-negative bacilli.

  9. Optimal resting-growth strategies of microbial populations in fluctuating environments.

    Directory of Open Access Journals (Sweden)

    Nico Geisel

    Full Text Available Bacteria spend most of their lifetime in non-growing states which allow them to survive extended periods of stress and starvation. When environments improve, they must quickly resume growth to maximize their share of limited nutrients. Cells with higher stress resistance often survive longer stress durations at the cost of needing more time to resume growth, a strong disadvantage in competitive environments. Here we analyze the basis of optimal strategies that microorganisms can use to cope with this tradeoff. We explicitly show that the prototypical inverse relation between stress resistance and growth rate can explain much of the different types of behavior observed in stressed microbial populations. Using analytical mathematical methods, we determine the environmental parameters that decide whether cells should remain vegetative upon stress exposure, downregulate their metabolism to an intermediate optimum level, or become dormant. We find that cell-cell variability, or intercellular noise, is consistently beneficial in the presence of extreme environmental fluctuations, and that it provides an efficient population-level mechanism for adaption in a deteriorating environment. Our results reveal key novel aspects of responsive phenotype switching and its role as an adaptive strategy in changing environments.

  10. Combined Effect of Nutrient and Pest Managements on Substrate Utilization Pattern of Soil Microbial Population in Hybrid Rice Cropping System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A field experiment was conducted to study the combined effect of nutrient and pest managements on soil biomass phospholipid contents, functional biodiversity and substrate utilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, P and K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100, 25, and 100 kg ha-1, respectively, and the various pesticides were applied at the recommended rates. The results of the experiment demonstrated a decline in the microbial abundance and soil microbial biomass phospholipid contents with the advancement of crop growth, and significant changes in substrate utilization pattern of soil microbial population studied were observed with different management practices and at different growth stages. The principal component analysis (PGA) using all 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicating that they have different patterns of carbon utilization under different habitats. The data showed that diversity in microbial community continuously changed with the progression in crop stage, particularly at physiological maturity (PM) stage that was evident from the utilization of different carbon sources at various crop stages.

  11. Microbial population dynamics and changes in main nutrients during the acidification process of pig manures

    Institute of Scientific and Technical Information of China (English)

    Dongdong Zhang; Xufeng Yuan; Peng Guo; Yali Suo; Xiaofen Wang; Weidong Wang; Zongjun Cui

    2011-01-01

    This study evaluated the impact of pig manure acidification on anaerobic treatment and composition of the fecal microbial community.According to the different chemical oxygen demand (COD) in the anaerobic treatment processes, pig manure was diluted 4 times (×4), 16 times (×l6), or 64 times (×64) and subjected to acidification.During the acidification process, pH, soluble chemical oxygen demand (SCOD), volatile fatty acids (VFAs), nitrogen (N), phosphorus (P) and potassium (K) were determined along with microbial population dynamics.The pH of the three dilutions first declined, and then slowly increased.The total VFAs of ×4 and ×l6 dilutions peaked on day 15 and 20, respectively.The content of acetic acid, propanoic acid, butanoic acid and valeric acid of the × 4 dilution were 23.6, 11.4, 8.8 and 0.6 g/L respectively, and that of the ×l6 dilution was 5.6, 2.3, 0.9 and 0.2 g/L respectively.Only acetic acid was detected in the ×64 dilution, and its level peaked on day 10.The results showed that the liquid pig manure was more suitable to enter the anaerobic methanogenic bioreactors after two weeks of acidification.During the acidification process, total P concentration increased during the first ten days, then dropped sharply, and rose again to a relatively high final concentration, while total N concentration rose initially and then declined.Based on the analysis of denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library, we concluded that the acidification process reduced the number of pathogenic bacteria species in pig manure.

  12. Identification of microbial populations driving biopolymer degradation in acidic peatlands by metatranscriptomic analysis.

    Science.gov (United States)

    Ivanova, Anastasia A; Wegner, Carl-Eric; Kim, Yongkyu; Liesack, Werner; Dedysh, Svetlana N

    2016-10-01

    Northern peatlands play a crucial role in the global carbon balance, serving as a persistent sink for atmospheric CO2 and a global carbon store. Their most extensive type, Sphagnum-dominated acidic peatlands, is inhabited by microorganisms with poorly understood degradation capabilities. Here, we applied a combination of barcoded pyrosequencing of SSU rRNA genes and Illumina RNA-Seq of total RNA (metatranscriptomics) to identify microbial populations and enzymes involved in degrading the major components of Sphagnum-derived litter and exoskeletons of peat-inhabiting arthropods: cellulose, xylan, pectin and chitin. Biopolymer addition to peat induced a threefold to fivefold increase in bacterial cell numbers. Functional community profiles of assembled mRNA differed between experimental treatments. In particular, pectin and xylan triggered increased transcript abundance of genes involved in energy metabolism and central carbon metabolism, such as glycolysis and TCA cycle. Concurrently, the substrate-induced activity of bacteria on these two biopolymers stimulated grazing of peat-inhabiting protozoa. Alveolata (ciliates) was the most responsive protozoa group as confirmed by analysis of both SSU rRNA genes and SSU rRNA. A stimulation of alphaproteobacterial methanotrophs on pectin was consistently shown by rRNA and mRNA data. Most likely, their significant enrichment was due to the utilization of methanol released during the degradation of pectin. Analysis of SSU rRNA and total mRNA revealed a specific response of Acidobacteria and Actinobacteria to chitin and pectin, respectively. Relatives of Telmatobacter bradus were most responsive among the Acidobacteria, while the actinobacterial response was primarily affiliated with Frankiales and Propionibacteriales. The expression of a wide repertoire of carbohydrate-active enzymes (CAZymes) corresponded well to the detection of a highly diverse peat-inhabiting microbial community, which is dominated by yet uncultivated

  13. Microbial population dynamics and changes in main nutrients during the acidification process of pig manures.

    Science.gov (United States)

    Zhang, Dongdong; Yuan, Xufeng; Guo, Peng; Suo, Yali; Wang, Xiaofen; Wang, Weidong; Cui, Zongjun

    2011-01-01

    This study evaluated the impact of pig manure acidification on anaerobic treatment and composition of the fecal microbial community. According to the different chemical oxygen demand (COD) in the anaerobic treatment processes, pig manure was diluted 4 times (x4), 16 times (x16), or 64 times (x64) and subjected to acidification. During the acidification process, pH, soluble chemical oxygen demand (SCOD), volatile fatty acids (VFAs), nitrogen (N), phosphorus (P) and potassium (K) were determined along with microbial population dynamics. The pH of the three dilutions first declined, and then slowly increased. The total VFAs of x4 and x16 dilutions peaked on day 15 and 20, respectively. The content of acetic acid, propanoic acid, butanoic acid and valeric acid of the x4 dilution were 23.6, 11.4, 8.8 and 0.6 g/L respectively, and that of the x16 dilution was 5.6, 2.3, 0.9 and 0.2 g/L respectively. Only acetic acid was detected in the x64 dilution, and its level peaked on day 10. The results showed that the liquid pig manure was more suitable to enter the anaerobic methanogenic bioreactors after two weeks of acidification. During the acidification process, total P concentration increased during the first ten days, then dropped sharply, and rose again to a relatively high final concentration, while total N concentration rose initially and then declined. Based on the analysis of denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library, we concluded that the acidification process reduced the number of pathogenic bacteria species in pig manure. PMID:21520820

  14. Biofilm removal technique using sands as a research tool for accessing microbial attachment on surface

    Directory of Open Access Journals (Sweden)

    Nathanon Trachoo

    2004-01-01

    Full Text Available Biofilms have profound impacts on improved survival of the constituent microorganisms in nature. Biofilms were believed to protect constituent microorganisms from sanitizer treatment, provide a more suitable habitat for microorganisms, and become a site for genetic material exchanges between microorganisms. As we realize more about the significance of biofilm, methods used for biofilm study should be consistently developed and evaluated. To determine microbial attachment on surfaces, usually biofilms are grown on substratum surfaces and removed by vortexing with glass beads or scraping. However, scraping is not as effective as vortexing with glass beads. Another approach is direct-agar overlaying which cannot be used with high density biofilm. In this experiment, we compared effectiveness of glass beads (298±28 μm in diameter and sands (width: 221±55 μm and length: 329±118 μm in removing biofilm of Pseudomonas aeruginosa by vortexing method. The results suggested that acid-washed sands, which are significantly less inexpensive than glass beads, were as effective as (P>0.05 analytical grade glass beads in Pseudomonas aeruginosa biofilm removal without inhibiting growth of the organism.

  15. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well.

    Science.gov (United States)

    Robbins, Steven J; Evans, Paul N; Parks, Donovan H; Golding, Suzanne D; Tyson, Gene W

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid.

  16. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well

    Science.gov (United States)

    Robbins, Steven J.; Evans, Paul N.; Parks, Donovan H.; Golding, Suzanne D.; Tyson, Gene W.

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid. PMID:27375557

  17. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well.

    Science.gov (United States)

    Robbins, Steven J; Evans, Paul N; Parks, Donovan H; Golding, Suzanne D; Tyson, Gene W

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid. PMID:27375557

  18. Genome-centric analysis of microbial populations enriched by hydraulic fracture fluid additives in a coal bed methane production well

    Directory of Open Access Journals (Sweden)

    Steven Jeffrey Robbins

    2016-06-01

    Full Text Available Coal bed methane (CBM is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid.

  19. 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...... probable number assays, and their presence was only detected in herbicide-exposed sediments. Similarly, PCR analysis showed that the 2,4-dichlorophe-noxyacetic acid degradation pathway genes tfdA and tfdB (10(2) to 10(3) gene copies g(-1) sediment) were only detected in sediments from contaminated areas...... of the aquifer. PCR-restriction fragment length polymorphism measurements demonstrated the presence of different populations of tfd genes, suggesting that the in situ herbicide degradation was caused by the activity of a heterogeneous population of phenoxy acid degraders. The number of Pseudomonas bacteria...

  20. Particulate DNA in smoker fluids: Evidence for existence of microbial populations in hot hydrothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Straube, W.L.; Colwell, R.R. (Univ. of Maryland, College Park (USA) Univ. of Maryland, Baltimore (USA)); Deming, J.W.; Baross, J.A. (Univ. of Washington, Seattle (USA)); Somerville, C.C. (Univ. of Maryland, College Park (USA))

    1990-05-01

    As part of an interdisciplinary study of hydrothermal vents on the Endeavour Segment of the Juan de Fuca Ridge, we used the submersible ALVIN to collect 57 fluid samples from 17 different hot vents (smokers and flanges) and their environs for the purpose of extracting particulate DNA. Particulate material concentrated from these samples was lysed enzymatically (enz) and by a combination of enzyme and French press treatment (fp). Concentrations of partially purified DNA recovered from these lysates were determined spectrofluorometrically. Ambient seawater surrounding the vents was found to contain low DNA concentrations, 0.18 to 0.32 ng of DNA per ml, while low-temperature vent samples yielded significantly higher concentrations of 0.37 to 2.12 ng of DNA per ml. Although DNA recovery values from superheated (210 to 345{degree}C) flange samples were not significantly different from ambient seawater values, most of the superheated (174 to 357{degree}C) smoker fluid samples contained particulate DNA in concentrations too high to be attributable to entrained seawater. Detailed sampling at one smoker site demonstrated not only the existence of significant levels of particulate DNA in the superheated smoker fluids but also the presence of an elevated microbial population in the buoyant plume 20 to 100 m above the smoker. These results underscore the heterogeneity of smoker environments within a given hydrothermal vent fluid and indicate that microorganisms exist in some superheated fluids.

  1. Microbial population index and community structure in saline-alkaline soil using gene targeted metagenomics.

    Science.gov (United States)

    Keshri, Jitendra; Mishra, Avinash; Jha, Bhavanath

    2013-03-30

    Population indices of bacteria and archaea were investigated from saline-alkaline soil and a possible microbe-environment pattern was established using gene targeted metagenomics. Clone libraries were constructed using 16S rRNA and functional gene(s) involved in carbon fixation (cbbL), nitrogen fixation (nifH), ammonia oxidation (amoA) and sulfur metabolism (apsA). Molecular phylogeny revealed the dominance of Actinobacteria, Firmicutes and Proteobacteria along with archaeal members of Halobacteraceae. The library consisted of novel bacterial (20%) and archaeal (38%) genera showing ≤95% similarity to previously retrieved sequences. Phylogenetic analysis indicated ability of inhabitant to survive in stress condition. The 16S rRNA gene libraries contained novel gene sequences and were distantly homologous with cultured bacteria. Functional gene libraries were found unique and most of the clones were distantly related to Proteobacteria, while clones of nifH gene library also showed homology with Cyanobacteria and Firmicutes. Quantitative real-time PCR exhibited that bacterial abundance was two orders of magnitude higher than archaeal. The gene(s) quantification indicated the size of the functional guilds harboring relevant key genes. The study provides insights on microbial ecology and different metabolic interactions occurring in saline-alkaline soil, possessing phylogenetically diverse groups of bacteria and archaea, which may be explored further for gene cataloging and metabolic profiling. PMID:23083746

  2. [Problems of accessibility for the population of Georgian modern outpatient and inpatient care].

    Science.gov (United States)

    Bolkvadze, R A; Gerzmava, O Kh

    2014-12-01

    Which began in 2013, the implementation of the priority national project - Universal health programs for population of Georgia - has important social significance, given the increased accessibility of the population in case of timely and quality medical care. Various forms of public participation in the payment of services received in varying degrees allow us to find a compromise between containment of demand and increase access to treatment. And if the insurance in its various forms, largely solves the last problem, but may create a problem of rising costs, the different types of direct payments more efficient demand, however creates a need to control access to health care for populations with a high demand for medical care. Co-payments under the defined government programs and directly to the patient, on the one hand, imply severally pay for health care and the fear of the occurrence of catastrophic costs of treatment, and on the other hand, allow you to control the rising costs of the health system. The problem of reducing the availability of medical care is overcome by introducing exemptions from co-payments for vulnerable groups, which in turn leads to a substantial increase in government spending. It must be emphasized that the tools developed and the results of the calculations can be used to compare the effects of the introduction of various schemes of co-payments and choose the most suitable scheme, in terms of the extent of the burden of private expenditure on treatment, as well as income and expenses of the health system in general. PMID:25617109

  3. Starving our microbial self: the deleterious consequences of a diet deficient in microbiota-accessible carbohydrates.

    Science.gov (United States)

    Sonnenburg, Erica D; Sonnenburg, Justin L

    2014-11-01

    The gut microbiota of a healthy person may not be equivalent to a healthy microbiota. It is possible that the Western microbiota is actually dysbiotic and predisposes individuals to a variety of diseases. The asymmetric plasticity between the relatively stable human genome and the more malleable gut microbiome suggests that incompatibilities between the two could rapidly arise. The Western lifestyle, which includes a diet low in microbiota-accessible carbohydrates (MACs), has selected for a microbiota with altered membership and functionality compared to those of groups living traditional lifestyles. Interactions between resident microbes and host leading to immune dysregulation may explain several diseases that share inflammation as a common basis. The low-MAC Western diet results in poor production of gut microbiota-generated short-chain fatty acids (SCFAs), which attenuate inflammation through a variety of mechanisms in mouse models. Studies focused on modern and traditional societies, combined with animal models, are needed to characterize the connection between diet, microbiota composition, and function. Differentiating between an optimal microbiota, one that increases disease risk, and one that is causative or potentiates disease will be required to further understand both the etiology and possible treatments for health problems related to microbiota dysbiosis. PMID:25156449

  4. Effects of Momordica charantia Saponins on In vitro Ruminal Fermentation and Microbial Population.

    Science.gov (United States)

    Kang, Jinhe; Zeng, Bo; Tang, Shaoxun; Wang, Min; Han, Xuefeng; Zhou, Chuanshe; Yan, Qiongxian; He, Zhixiong; Liu, Jinfu; Tan, Zhiliang

    2016-04-01

    This study was conducted to investigate the effects of Momordica charantia saponin (MCS) on ruminal fermentation of maize stover and abundance of selected microbial populations in vitro. Five levels of MCS supplements (0, 0.01, 0.06, 0.30, 0.60 mg/mL) were tested. The pH, NH3-N, and volatile fatty acid were measured at 6, 24, 48 h of in vitro mixed incubation fluids, whilst the selected microbial populations were determined at 6 and 24 h. The high dose of MCS increased the initial fractional rate of degradation at t-value = 0 (FRD0) and the fractional rate of gas production (k), but decreased the theoretical maximum of gas production (V F) and the half-life (t0.5) compared with the control. The NH3-N concentration reached the lowest concentration with 0.01 mg MCS/mL at 6 h. The MSC inclusion increased (p<0.001) the molar proportion of butyrate, isovalerate at 24 h and 48 h, and the molar proportion of acetate at 24 h, but then decreased (p<0.05) them at 48 h. The molar proportion of valerate was increased (p<0.05) at 24 h. The acetate to propionate ratio (A/P; linear, p<0.01) was increased at 24 h, but reached the least value at the level of 0.30 mg/mL MCS. The MCS inclusion decreased (p<0.05) the molar proportion of propionate at 24 h and then increased it at 48 h. The concentration of total volatile fatty acid was decreased (p<0.001) at 24 h, but reached the greatest concentration at the level of 0.01 mg/mL and the least concentration at the level of 0.60 mg/mL. The relative abundance of Ruminococcus albus was increased at 6 h and 24 h, and the relative abundance of Fibrobacter succinogenes was the lowest (p<0.05) at 0.60 mg/mL at 6 h and 24 h. The relative abundance of Butyrivibrio fibrisolvens and fungus reached the greatest value (p<0.05) at low doses of MCS inclusion and the least value (p<0.05) at 0.60 mg/mL at 24 h. The present results demonstrates that a high level of MCS quickly inhibits in vitro fermentation of maize stover, while MCS at low doses has

  5. Accessibility to health services in the prison population in Colombia: a public health challenge

    Directory of Open Access Journals (Sweden)

    Luz Mery Mejía O

    2010-08-01

    Full Text Available This article is the result of a product of a study elaborated with the aim of systematizing the available information related to the accessibility to the health services of the prison population in the penitentiary centers. To this end, we reviewed the literature and systematic collection of the academic available material in the principal university libraries in the city of Medellin, scientific databases and the web pages of national and international organizations that have dealt with this topic. The information was systematized considering some historical references to prisons and health, the record of experiences in some countries and the current regulations for health care in the prison population in the Colombian case. We conclude that although significant progress has been made to ensure health care for the prison population, in the prison there are still obstacles and limitations that infringe the right to health of this population. Likewise, it is evidenced that it has not been considered a public health problem in the country, which it is considered a challenge to incorporate it as such.

  6. 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.

  7. Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake (RFI) offered contrasting diets

    OpenAIRE

    Carberry, CIara A.; Kenny, David A.; Kelly, Alan K.; Waters, Sinéad M

    2014-01-01

    Background Methane (CH4) emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency. The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake (RFI) while offered (i) a low energy high forage (HF) diet followed by (ii) a high energy low forage (LF) ...

  8. 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 m......, respectively. Both the total gut microflora and the coliform flora were influenced by the dietary NSP content....

  9. Effects of butachlor on microbial populations and enzyme activities in paddy soil.

    Science.gov (United States)

    Min, H; Ye, Y F; Chen, Z Y; Wu, W X; Yufeng, D

    2001-09-01

    This paper reports the influences of the herbicide butachlor (n-butoxymethlchloro -2', 6'-diethylacetnilide) on microbial populations, respiration, nitrogen fixation and nitrification, and on the activities of dehydrogenase and hydrogen peroxidase in paddy soil. The results showed that the number of actinomycetes declined significantly after the application of butachlor at different concentrations ranging from 5.5 microg g(-1) to 22.0 microg g(-1) dried soil, while that of bacteria and fungi increased. Fungi were easily affected by butachlor compared to the bacteria. The growth of fungi was retarded by butachlor at higher concentrations. Butachlor however, stimulated the growth of anaerobic hydrolytic fermentative bacteria, sulfate-reducing bacteria (SRB) and denitrifying bacteria. The increased concentration of butachlor applied resulted in the higher number of SRB. Butachlor inhibited the growth of hydrogen-producing acetogenic bacteria. The effect of butachlor varied on methane-producing bacteria (MPB) at different concentrations. Butachlor at the concentration of 1.0 microg g(-1) dried soil or less than this concentration accelerated the growth of MPB, while at 22.0 microg g(-1) dried soil showed an inhibition. Butachlor enhanced the activity of dehydrogenase at increasing concentrations. The soil dehydrogenase showed the highest activity on the 16th day after application of 22.0 microg g(-1) dried soil of butachlor. The hydrogen peroxidase could be stimulated by butachlor. The soil respiration was depressed during the period from several days to more than 20 days, depending on concentrations of butachlor applied. Both the nitrogen fixation and nitrification were stimulated in the beginning but reduced greatly afterwards in paddy soil.

  10. Particulate DNA in smoker fluids: evidence for existence of microbial populations in hot hydrothermal systems.

    Science.gov (United States)

    Straube, W L; Deming, J W; Somerville, C C; Colwell, R R; Baross, J A

    1990-05-01

    As part of an interdisciplinary study of hydrothermal vents on the Endeavour Segment of the Juan de Fuca Ridge, we used the submersible ALVIN to collect 57 fluid samples in titanium syringes and Go Flo Niskin bottles from 17 different hot vents (smokers and flanges) and their environs for the purpose of extracting particulate DNA. The relative purity of the vent fluids collected was determined by Mg content as an indicator of seawater entrainment. Particulate material concentrated from these samples was lysed enzymatically (enz) and by a combination of enzyme and French press treatment (fp). Concentrations of partially purified DNA recovered from these lysates were determined spectrofluorometrically by using the dye Hoechst 33258. Ambient seawater surrounding the vents was found to contain low DNA concentrations, 0.18 to 0.32 ng of DNA per ml (n = 4; mean(enz) = 0.23 +/- 0.05; mean(fp) = 0.26 +/- 0.05), while low-temperature vent samples yielded significantly higher concentrations of 0.37 to 2.12 ng of DNA per ml (n = 4; mean(enz) = 0.97 +/- 0.68; mean(fp) = 1.05 +/- 0.54). Although DNA recovery values from superheated (210 to 345 degrees C) flange samples (mean(enz) = 0.14 +/- 0.10; mean(fp) = 0.12 +/- 0.14) were not significantly different from ambient seawater values, most of the superheated (174 to 357 degrees C) smoker fluid samples contained particulate DNA in concentrations too high to be attributable to entrained seawater. Detailed sampling at one smoker site demonstrated not only the existence of significant levels of particulate DNA in the superheated smoker fluids but also the presence of an elevated microbial population in the buoyant plume 20 to 100 m above the smoker. These results underscore the heterogeneity of smoker environments within a given hydrothermal vent field and indicate that microorganisms exist in some superheated fluids. PMID:16348193

  11. A bayesian approach to inferring the genetic population structure of sugarcane accessions from INTA (Argentina

    Directory of Open Access Journals (Sweden)

    Mariana Inés Pocovi

    2015-06-01

    Full Text Available Understanding the population structure and genetic diversity in sugarcane (Saccharum officinarum L. accessions from INTA germplasm bank (Argentina will be of great importance for germplasm collection and breeding improvement as it will identify diverse parental combinations to create segregating progenies with maximum genetic variability for further selection. A Bayesian approach, ordination methods (PCoA, Principal Coordinate Analysis and clustering analysis (UPGMA, Unweighted Pair Group Method with Arithmetic Mean were applied to this purpose. Sixty three INTA sugarcane hybrids were genotyped for 107 Simple Sequence Repeat (SSR and 136 Amplified Fragment Length Polymorphism (AFLP loci. Given the low probability values found with AFLP for individual assignment (4.7%, microsatellites seemed to perform better (54% for STRUCTURE analysis that revealed the germplasm to exist in five optimum groups with partly corresponding to their origin. However clusters shown high degree of admixture, F ST values confirmed the existence of differences among groups. Dissimilarity coefficients ranged from 0.079 to 0.651. PCoA separated sugarcane in groups that did not agree with those identified by STRUCTURE. The clustering including all genotypes neither showed resemblance to populations find by STRUCTURE, but clustering performed considering only individuals displaying a proportional membership > 0.6 in their primary population obtained with STRUCTURE showed close similarities. The Bayesian method indubitably brought more information on cultivar origins than classical PCoA and hierarchical clustering method.

  12. Effects of Fructooligosaccharides,compared with Direct-Fed Microbial Bacteria,and Zinc Bacitracin on Cecal Microbial Populations and Performance of Broilers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experiment was conducted to determine the effects of dietary fructooligosaccharides(FOS),compared with direct-fed microbial bacteria (DFM),and zinc bacitracin ,on cecal microbial populations and performance of broiler Chickens. One hundred and ninety-two broilers (Avian) were randomly assigned to four groups,with four replicates of 12 birds each. The control group was fed with the basal diet,without any drug additive. FOS,DFM and zine bacitracin was respectively added to the basal diet at the level of 1.5% ,800 mg@kg-1 and 300 mg@ kg-1 to form the experimental diets. Body weight ,feed intake and feed efficiency were measured weekly. The feeding trial started at 1 d and ended at 21 d. At day 14 and day 21 ,four broilers per group were killed and cecum waa taken to determined microflors and pH. The results showed that dietary FOS increased bifidobactrial concentration by 1. 75-fold( P <0. 05) at 14 d of age and 1.45-fold( P <0. 05) at 21 d of age compared with control. FOS had no effect on concnetrations of E. coli and pH. There were no dietary effects of FOS,DFM,and zinc bacitracin on weight gain,feed intake,feed conversion( P >0. 05).

  13. Distance matters: a population based study examining access to maternity services for rural women

    Directory of Open Access Journals (Sweden)

    Kornelsen Jude

    2011-06-01

    Full Text Available Abstract Background In the past fifteen years there has been a wave of closures of small maternity services in Canada and other developed nations which results in the need for rural parturient women to travel to access care. The purpose of our study is to systematically document newborn and maternal outcomes as they relate to distance to travel to access the nearest maternity services with Cesarean section capabililty. Methods Study population is all women carrying a singleton pregnancy beyond 20 weeks and delivering between April 1, 2000 and March 31, 2004 and residing outside of the core urban areas of British Columbia. Maternal and newborn data was linked to specific geographic catchments by the B.C. Perinatal Health Program. Catchments were stratified by distance to nearest maternity service with Cesarean section capabililty if greater than 1 hour travel time or level of local service. Hierarchical logistic regression was used to test predictors of adverse newborn and maternal outcomes. Results 49,402 cases of women and newborns resident in rural catchments were included. Adjusted odds ratios for perinatal mortality for newborns from catchments greater than 4 hours from services was 3.17 (95% CI 1.45-6.95. Newborns from catchments 2 to 4 hours, and 1 to 2 hours from services generated rates of 179 and 100 NICU 3 days per thousand births respectively compared to 42 days for newborns from catchments served by specialists. Conclusions Distance matters: rural parturient women who have to travel to access maternity services have increased rates of adverse perinatal outcomes.

  14. Microbial population dynamics in an anaerobic CSTR treating a chemical synthesis-based pharmaceutical wastewater.

    Science.gov (United States)

    Oz, Nilgun Ayman; Ince, Orhan; Ince, Bahar Kasapgil; Akarsubasi, Alper Tunga; Eyice, Ozge

    2003-01-01

    Effects of a chemical synthesis based pharmaceutical wastewater on performance of an anaerobic completely stirred tank reactor (CSTR), activity of acetoclastic methanogens and microbial composition were evaluated under various influent compositions. Initially, the CSTR was fed with glucose up to an organic loading rate (OLR) of 6 kg COD/m3 x d corresponding to an F/M ratio of 0.43 with a hydraulic retention time (HRT) of 2.5 days. A COD removal efficiency of 92% and a methane yield of 0.32 m3 CH4/kg COD(removed) were achieved whilst specific methanogenic activity (SMA) was found to be 336mL CH4/gTVS x d. After the CSTR was fed with pre-aerated wastewater diluted by glucose in different dilution ratios of 10% (w/v), 30% (w/v), 70% (w/v), and 100% (w/v) pre-aerated wastewater, gradual decreases in COD removal efficiency to 71%, methane yield to 0.28 m3CH4/kg COD(removed) and SMA to 166 mL CH4/gTVS d occurred whilst volatile fatty acid concentration reached to 1474 mg/L. After the raw wastewater diluted with the pre-aerated wastewater was fed into the CSTR in increasing ratios of 10% (w/v), 30% (w/v), and 60% (w/v), there was a proportional deterioration in performance in terms of COD removal efficiency, methane yield and acetoclastic methanogenic activity. Epifluorescence microscopy of the seed sludge revealed that Methanococcus-like species, short, and medium rods were found to be equally dominant. The short and medium rod species remained equally dominant groups in the CSTR throughout the feeding regime whilst Methanococcus-like species and long rods were found to be in insignificant numbers at the end of the study. Changes in archael diversity were determined using molecular analyses such as polymerase chain reaction (PCR), and denaturent gradient gel electrophoresis (DGGE). Results showed that overall archeal diversity did not change much whereas changes in composition of eubacterial population occurred.

  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 Accumulibact...

  16. 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...

  17. 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 s

  18. Heterotrophic and Autotrophic Microbial Populations in Cold Perennial Springs of the High Arctic ▿ †

    Science.gov (United States)

    Perreault, Nancy N.; Greer, Charles W.; Andersen, Dale T.; Tille, Stefanie; Lacrampe-Couloume, Georges; Lollar, Barbara Sherwood; Whyte, Lyle G.

    2008-01-01

    The saline springs of Gypsum Hill in the Canadian high Arctic are a rare example of cold springs originating from deep groundwater and rising to the surface through thick permafrost. The heterotrophic bacteria and autotrophic sulfur-oxidizing bacteria (up to 40% of the total microbial community) isolated from the spring waters and sediments were classified into four phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) based on 16S rRNA gene analysis; heterotrophic isolates were primarily psychrotolerant, salt-tolerant, facultative anaerobes. Some of the isolates contained genes for thiosulfate oxidation (soxB) and anoxygenic photosynthesis (pufM), possibly enabling the strains to better compete in these sulfur-rich environments subject to long periods of illumination in the Arctic summer. Although leucine uptake by the spring water microbial community was low, CO2 uptake was relatively high under dark incubation, reinforcing the idea that primary production by chemoautotrophs is an important process in the springs. The small amounts of hydrocarbons in gases exsolving from the springs (0.38 to 0.51% CH4) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy. Anaerobic heterotrophic sulfur oxidation and aerobic autotrophic sulfur oxidation activities were demonstrated in sediment slurries. Overall, our results describe an active microbial community capable of sustainability in an extreme environment that experiences prolonged periods of continuous light or darkness, low temperatures, and moderate salinity, where life seems to rely on chemolithoautotrophy. PMID:18805995

  19. 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...

  20. Large-scale distribution of microbial and viral populations in the South Atlantic Ocean

    NARCIS (Netherlands)

    De Corte, D.; Sintes, E.; Yokokawa, T.; Lekunberri, I.; Herndl, G.

    2016-01-01

    Viruses are abundant, diverse and dynamic compo-nents of the marine environments and play a signi?-cant role in the ocean biogeochemical cycles. Toassess potential variations in the relation betweenviruses and microbes in different geographic regionsand depths, viral and microbial abundance and pro-

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

    NARCIS (Netherlands)

    Thomas, R.Z.; Zijnge, V.; Cicek, A.; Soet, J.J. de; Harmsen, H.J.; 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 sectio

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

    NARCIS (Netherlands)

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

    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 sectio

  3. 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, sulfate-re

  4. 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 sectio

  5. Access to primary care and visits to emergency departments in England: a cross-sectional, population-based study.

    Directory of Open Access Journals (Sweden)

    Thomas E Cowling

    Full Text Available BACKGROUND: The number of visits to hospital emergency departments (EDs in England has increased by 20% since 2007-08, placing unsustainable pressure on the National Health Service (NHS. Some patients attend EDs because they are unable to access primary care services. This study examined the association between access to primary care and ED visits in England. METHODS: A cross-sectional, population-based analysis of patients registered with 7,856 general practices in England was conducted, for the time period April 2010 to March 2011. The outcome measure was the number of self-referred discharged ED visits by the registered population of a general practice. The predictor variables were measures of patient-reported access to general practice services; these were entered into a negative binomial regression model with variables to control for the characteristics of patient populations, supply of general practitioners and travel times to health services. MAIN RESULT AND CONCLUSION: General practices providing more timely access to primary care had fewer self-referred discharged ED visits per registered patient (for the most accessible quintile of practices, RR = 0.898; P<0.001. Policy makers should consider improving timely access to primary care when developing plans to reduce ED utilisation.

  6. Microbial populations identified by fluorescence in situ hybridization in a constructed wetland treating acid coal mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nicomrat, D.; Dick, W.A.; Tuovinen, O.H. [Ohio State University, Wooster, OH (United States). Environmental Science Graduate Programme

    2006-07-15

    Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe- and S-oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at < 0.01% of the total microbial community. The most numerous bacterial species in this wetland system was Acidithiobacillus ferrooxidans, comprising up to 37% of the bacterial population. Acidithiobacillus thiooxidans was also abundant.

  7. Microbial Nitrogen Transformations in the Oxygen Minimum Zone off Peru, 01 February 1985 to 05 March 1985 (NODC Accession 9200026)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NITROP - 85 was the major field of experiment of an N.S.F. funded program entitled "Microbial Nitrogen Transformations in the Oxygen Minimum Zone off Peru". this...

  8. Among-population variation in microbial community structure in the floral nectar of the bee-pollinated forest herb Pulmonaria officinalis L.

    Directory of Open Access Journals (Sweden)

    Hans Jacquemyn

    Full Text Available 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

  9. Access and Attitudes to HPV Vaccination amongst Hard-To-Reach Populations in Kenya.

    Directory of Open Access Journals (Sweden)

    Deborah Watson-Jones

    Full Text Available Sub-Saharan Africa bears the greatest burden of cervical cancer. Human papillomavirus (HPV vaccination programmes to prevent the disease will need to reach vulnerable girls who may not be able access health and screening services in the future. We conducted formative research on facilitators and barriers to HPV vaccination and potential acceptability of a future HPV vaccination programme amongst girls living in hard-to-reach populations in Kenya.Stakeholder interviews with Ministry of Health staff explored barriers to and support for the uptake of HPV vaccination. A situation assessment was conducted to assess community services in Maasai nomadic pastoralist communities in Kajiado County and in Korogocho informal settlement in Nairobi city, followed by focus group discussions (n=14 and semi-structured interviews (n=28 with health workers, parents, youth, and community and religious leaders. These covered marriage, knowledge of cervical cancer and HPV, factors that might inhibit or support HPV vaccine uptake and intention to accept HPV vaccine if a programme was in place.Reported challenges to an HPV vaccination programme included school absenteeism and drop-out, early age of sex and marriage, lack of parental support, population mobility and distance from services. Despite little prior knowledge of cervical cancer and HPV, communities were interested in receiving HPV vaccination. Adequate social mobilisation and school-based vaccination, supplemented by out-reach activities, were considered important facilitating factors to achieve high coverage. There was some support for a campaign approach to vaccine delivery.Given the high level of support for a vaccine against cervical cancer and the experience of reaching pastoralist and slum-dwellers for other immunizations, implementing an HPV vaccine programme should be feasible in such hard-to-reach communities. This may require additional delivery strategies in addition to the standard school

  10. Access and completion of a Web-based treatment in a population-based sample of tornado-affected adolescents.

    Science.gov (United States)

    Price, Matthew; Yuen, Erica K; Davidson, Tatiana M; Hubel, Grace; Ruggiero, Kenneth J

    2015-08-01

    Although Web-based treatments have significant potential to assess and treat difficult-to-reach populations, such as trauma-exposed adolescents, the extent that such treatments are accessed and used is unclear. The present study evaluated the proportion of adolescents who accessed and completed a Web-based treatment for postdisaster mental health symptoms. Correlates of access and completion were examined. A sample of 2,000 adolescents living in tornado-affected communities was assessed via structured telephone interview and invited to a Web-based treatment. The modular treatment addressed symptoms of posttraumatic stress disorder, depression, and alcohol and tobacco use. Participants were randomized to experimental or control conditions after accessing the site. Overall access for the intervention was 35.8%. Module completion for those who accessed ranged from 52.8% to 85.6%. Adolescents with parents who used the Internet to obtain health-related information were more likely to access the treatment. Adolescent males were less likely to access the treatment. Future work is needed to identify strategies to further increase the reach of Web-based treatments to provide clinical services in a postdisaster context. PMID:25622071

  11. 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.

  12. Involvement of microbial populations during the composting of olive mill wastewater sludge.

    Science.gov (United States)

    Abid, N; Chamkha, M; Godon, J J; Sayadi, S

    2007-07-01

    Olive mill waste water sludge obtained by the electro-Fenton oxidation of olive mill waste water was composted in a bench scale reactor. The evolution of microbial species within the composter was investigated using a respirometric test and by means of both cultivation-dependent and independent approaches (Polymerase Chain Reaction-Single Strand Conformation Polymorphism, PCR SSCP). During the period of high respiration rate (7-24 days), cultivation method showed that thermophilic bacteria as well as actinomycetes dominated over eumycetes. During the composting process, the PCR-SSCP method showed a higher diversity of the bacterial community than the eukaryotic one. After 60 days of composting, the compost exhibited a microbial stability and a clear absence of phytotoxicity.

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

    DEFF Research Database (Denmark)

    Ludvigsen, L; Albrechtsen, HJ; Ringelberg, DB;

    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...... in PLFA profiles indicated that a shift in microbial community composition occurred with increasing horizontal distance from the landfill. The types and patterns of lipid biomarkers suggested that increased proportions of sulfate- and iron-reducing bacteria as well as certain microeukaryotes existed...... 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...

  14. 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

    2013-04-01

    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.

  15. Yellow Codfish Curing Process: Dynamics of Microbial Population, Sensory Descriptors and Chemical Indicators

    OpenAIRE

    Dias, Susana Maria Pereira

    2013-01-01

    Doutoramento em Engenharia Alimentar - Instituto Superior de Agronomia It was demonstrated that yellow cure codfish involves a substantial microbial activity, contrasting with dry-salted-codfish (white-cure-codfish) which presents lower microorganisms level. The salt content decreases during the salted-raw-codfish soaking, favouring the existing microorganisms activity. The subsequent drying step benefits proteolytic, amonifing and trimethylamine producing bacteria, with a corresponding...

  16. Constraint-based modelling of mixed microbial populations: Application to polyhydroxyalkanoates production

    OpenAIRE

    Pardelha, Filipa Alexandra Guerreiro

    2013-01-01

    The combined use of mixed microbial cultures (MMC) and fermented feedstock as substrate may significantly decrease polyhydroxyalkanoates (PHA) production costs and make them more competitive in relation to conventional petroleum-based polymers. However, there still exists a lack of knowledge at metabolic level that limits the development of strategies to make this process more effective. In this thesis, system biology computational tools were developed and applied to PHA production by MMC fro...

  17. Zinc, cadmium and lead accumulation and characteristics of rhizosphere microbial population associated with hyperaccumulator Sedum alfredii Hance under natural conditions.

    Science.gov (United States)

    Long, Xin-Xian; Zhang, Yu-Gang; Jun, Dai; Zhou, Qixing

    2009-04-01

    A field survey was conducted to study the characteristics of zinc, cadmium, and lead accumulation and rhizosphere microbial population associated with hyperaccumulator Sedum alfredii Hance growing natively on an old lead/zinc mining site. We found significant hyperaccumulation of zinc and cadmium in field samples of S. alfredii, with maximal shoot concentrations of 9.10-19.61 g kg(-1) zinc and 0.12-1.23 g kg(-1) cadmium, shoot/root ratios ranging from 1.75 to 3.19 (average 2.54) for zinc, 3.36 to 4.43 (average 3.85) for cadmium, shoot bioaccumulation factors of zinc and cadmium being 1.46-4.84 and 7.35-17.41, respectively. While most of lead was retained in roots, thus indicating exclusion as a tolerance strategy for lead. Compared to the non-rhizosphere soil, organic matter and total nitrogen and phosphorus content, CEC and water extractable zinc, cadmium, and lead concentration were significantly higher, but pH was smaller in rhizosphere soil. The rhizosphere soil of S. alfredii harbored a wide variety of microorganism. In general, significantly higher numbers of culturable bacteria, actinomycetes, and fungi were found in the rhizosphere compared to bulk soil, confirming the stimulatory effect of the S. alfredii rhizosphere on microbial growth and proliferation. Analyses of BIOLOG data also showed that the growth of S. alfredii resulted in observable changes in BIOLOG metabolic profiles, utilization ability of different carbon substrates of microbial communities in the rhizosphere soil were also higher than the non-rhizosphere, confirming a functional effect of the rhizosphere of S. alfredii on bacterial population. PMID:19183820

  18. 16S rRNA gene sequencing as a tool to study microbial populations in foods and process environments

    DEFF Research Database (Denmark)

    Buschhardt, Tasja; Hansen, Tina Beck; Bahl, Martin Iain;

    2015-01-01

    reference. Results: Taxonomic assignments and abundances of sequences in the total community and in the Enterobacteriaceae subpopulation were affected by the 16S rRNA gene variable region, DNA extraction methods, and polymerases chosen. However, community compositions were very reproducible when the same...... methods were used. Conclusions: Altogether, we have shown that conclusions from population studies based on 16S rRNA gene sequencing need to be made with caution. Overcoming the constraints, we believe that population studies can give new research possibilities for e.g. interaction studies, identification......Introduction: Methodological constraints during culturing and biochemical testing have left the true microbiological diversity of foods and process environments unexplored. Culture-independent molecular methods, such as 16S rRNA gene sequencing, may provide deeper insight into microbial communities...

  19. Population dynamics and spatial distribution of microbial species in multispecies biofilms under the action of direct electric current

    Institute of Scientific and Technical Information of China (English)

    CAO Hongbin; LI Xingang; WU Jinchuan; ZHONG Fangli; ZHANG Yi

    2003-01-01

    The metabolism, population dynamics and spatial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were investigated by using the micro-slicing technique. The nitrification rate of nitrifying bacteria was severely inhibited by a current over 10 Am-2 at lower C/N ratios. Compared to heterotrophs, the nitrifying bacteria in the surface biofilms were severely inhibited, resulting in a significant decrease in bacterial density. An increase in current density narrowed the less current-sensitive inner biofilm region, and in addition the density of NO2-oxidizers decreased more significantly than that of NH4-oxidizers in the surface biofilms probably due to electrochemical reactions at the anode. However, the effect of current on both the population dynamics and the spatial distribution of the microbial species was less significant at larger C/N ratios.

  20. Archaeal Populations in Hypersaline Sediments Underlying Orange Microbial Mats in the Napoli Mud Volcano▿†

    Science.gov (United States)

    Lazar, Cassandre Sara; L'Haridon, Stéphane; Pignet, Patricia; Toffin, Laurent

    2011-01-01

    Microbial mats in marine cold seeps are known to be associated with ascending sulfide- and methane-rich fluids. Hence, they could be visible indicators of anaerobic oxidation of methane (AOM) and methane cycling processes in underlying sediments. The Napoli mud volcano is situated in the Olimpi Area that lies on saline deposits; from there, brine fluids migrate upward to the seafloor. Sediments associated with a brine pool and microbial orange mats of the Napoli mud volcano were recovered during the Medeco cruise. Based on analysis of RNA-derived sequences, the “active” archaeal community was composed of many uncultured lineages, such as rice cluster V or marine benthic group D. Function methyl coenzyme M reductase (mcrA) genes were affiliated with the anaerobic methanotrophic Archaea (ANME) of the ANME-1, ANME-2a, and ANME-2c groups, suggesting that AOM occurred in these sediment layers. Enrichment cultures showed the presence of viable marine methylotrophic Methanococcoides in shallow sediment layers. Thus, the archaeal community diversity seems to show that active methane cycling took place in the hypersaline microbial mat-associated sediments of the Napoli mud volcano. PMID:21335391

  1. 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.

  2. 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

    2016-01-01

    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 Metagenomes from the three water types were used for reconstruction of 69 distinct microbial genomes, each with >86% coverage. The populations were dominated by Proteobacteria, Candidate divisions, unclassified archaea and unclassified bacteria. The estimated genome sizes of the <0.22 μm populations were generally smaller than their phylogenetically closest relatives, suggesting that small dimensions along with a reduced genome size may be adaptations to oligotrophy. Shallow ‘modern marine' water showed community members with a predominantly heterotrophic lifestyle. In contrast, the deeper, ‘old saline' water adhered more closely to the current paradigm of a hydrogen-driven deep biosphere. The data were finally used to create a combined metabolic model of the deep terrestrial biosphere microbial community. PMID:26484735

  3. Microbial population in the rumen of swamp buffalo (Bubalus bubalis) as influenced by coconut oil and mangosteen peel supplementation.

    Science.gov (United States)

    Pilajun, R; Wanapat, M

    2013-06-01

    Four, rumen fistulated swamp buffalo bulls were used to study microbial populations in the rumen when supplemented with coconut oil and mangosteen peel. Animals were randomly assigned to a 4 × 4 Latin square design. Four treatments were un-supplemented (Control), supplementation with coconut oil at 50 g/kg (CO5), supplementation with mangosteen peel at 30 g/kg (MP3) and supplementation with CO5 and MP3 (COM), of total DM intake. Animals received concentrate at 10 g/kg of BW, and rice straw was given ad libitum. Abundance of total bacteria was increased by CO5 supplementation, whereas populations of protozoa and Fibrobacter succinogenes were reduced by CO5 and COM supplementation. Dietary supplementation did not affect methanogen, Ruminococcus flavefaciens or Ruminococcus albus abundances. Dietary treatments changed denaturing gradient gel electrophoresis (DGGE) band patterns of methanogens and protozoa when compared with the control group, especially when supplemented with MP3. Supplementation of COM resulted in the greatest difference in pattern of DGGE bands for total bacteria compared with the control. Coconut oil and mangosteen peel supplementation resulted in changing of rumen microbial abundances and communities; however, combination of them could be more benefit to improve rumen fermentation of swamp buffalo fed on rice straw.

  4. The assessment of land exploitation by enumerating microbial population: Case study in several locations at Dieng Plateau

    Directory of Open Access Journals (Sweden)

    Sri Sumarsih

    2013-09-01

    Full Text Available Agricultural intensification program in Indonesia which is carried out by using high yield variety, high chemicals use and soil disturbances tends to trigger land exploitation. Land exploitation, performed without considering the land’s capability can generate degradations on the land itself. Various methods have been used to determine land exploitation level, including evaluation of soil microbe resources as on soil component. This research is aimed to assess land exploitation level, based on the amount of microbial population. The result of this research is expected to add the soil quality standard criteria. In the case study performed in Dieng plateau, representative soil sampling method was used. The amount of microbial population can be enumerated using plating and MPN method. Based on nutrient availability to indicate the soil biological characteristics, the soil under the trees, shrub, and Colocasia were classified as “below normal”, and the soil under the grass, tobacco, cabbage and potato were classified as “normal”. It shows that the land exploitation at the agricultural soils were still in the range of its land capability.

  5. Segregated flux balance analysis constrained by population structure/function data: the case of PHA production by mixed microbial cultures.

    Science.gov (United States)

    Pardelha, F; Albuquerque, M G E; Carvalho, G; Reis, M A M; Dias, J M L; Oliveira, R

    2013-08-01

    In this study we developed a segregated flux balance analysis (FBA) method to calculate metabolic flux distributions of the individual populations present in a mixed microbial culture (MMC). Population specific flux data constraints were derived from the raw data typically obtained by the fluorescence in situ hybridization (FISH) and microautoradiography (MAR)-FISH techniques. This method was applied to study the metabolic heterogeneity of a MMC that produces polyhydroxyalkanoates (PHA) from fermented sugar cane molasses. Three populations were identified by FISH, namely Paracoccus sp., Thauera sp., and Azoarcus sp. The segregated FBA method predicts a flux distribution for each of the identified populations. The method is shown to predict with high accuracy the average PHA storage flux and the respective monomeric composition for 16 independent experiments. Moreover, flux predictions by segregated FBA were slightly better than those obtained by nonsegregated FBA, and also highly concordant with metabolic flux analysis (MFA) estimated fluxes. The segregated FBA method can be of high value to assess metabolic heterogeneity in MMC systems and to derive more efficient eco-engineering strategies. For the case of PHA-producing MMC considered in this work, it becomes apparent that the PHA average monomeric composition might be controlled not only by the volatile fatty acids (VFA) feeding profile but also by the population composition present in the MMC. PMID:23475571

  6. Work-First Federal Policies: Eroding Access to Community Colleges for Latinos and Low-Income Populations

    Science.gov (United States)

    Shaw, Kathleen M.; Goldrick-Rab, Sara

    2006-01-01

    This chapter describes how the implementation of the 1996 welfare reform and the 1998 Workforce Investment Acts affected community colleges' willingness and capacity to provide access to postsecondary education and training for Latinos and other low-income populations. (Contains 3 figures.)

  7. Impacts of Free Radicals on the Dynamics of Marine Microbial Populations

    Digital Repository Service at National Institute of Oceanography (India)

    Gu, Ji-Dong

    D and similarly oxidative stress induces oxyR gene and SOS response recA and lexA genes (Neidardt, 1987). As the technological advancement being made in the past several years, it is feasible to examine this interesting and important issue to obtain crucial... in the ocean, sequestration of iron form the environment and effect of iron on biology of bacteria are indispensable information in microbial ecology. Future perspectives Due to the technological advances in instrumentation for detection of short-life chemical...

  8. Effects of Flavonoids on Rumen Fermentation Activity, Methane Production, and Microbial Population

    OpenAIRE

    Ehsan Oskoueian; Norhani Abdullah; Armin Oskoueian

    2013-01-01

    This research was carried out to evaluate the effects of flavone, myricetin, naringin, catechin, rutin, quercetin, and kaempferol at the concentration of 4.5% of the substrate (dry matter basis) on the rumen microbial activity in vitro. Mixture of guinea grass and concentrate (60 : 40) was used as the substrate. The results showed that all the flavonoids except naringin and quercetin significantly (P < 0.05) decreased the dry matter degradability. The gas production significantly (P < 0.05) d...

  9. 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.

  10. Using populations of human and microbial genomes for organism detection in metagenomes

    Science.gov (United States)

    Ames, Sasha K.; Gardner, Shea N.; Marti, Jose Manuel; Slezak, Tom R.; Gokhale, Maya B.; Allen, Jonathan E.

    2015-01-01

    Identifying causative disease agents in human patients from shotgun metagenomic sequencing (SMS) presents a powerful tool to apply when other targeted diagnostics fail. Numerous technical challenges remain, however, before SMS can move beyond the role of research tool. Accurately separating the known and unknown organism content remains difficult, particularly when SMS is applied as a last resort. The true amount of human DNA that remains in a sample after screening against the human reference genome and filtering nonbiological components left from library preparation has previously been underreported. In this study, we create the most comprehensive collection of microbial and reference-free human genetic variation available in a database optimized for efficient metagenomic search by extracting sequences from GenBank and the 1000 Genomes Project. The results reveal new human sequences found in individual Human Microbiome Project (HMP) samples. Individual samples contain up to 95% human sequence, and 4% of the individual HMP samples contain 10% or more human reads. Left unidentified, human reads can complicate and slow down further analysis and lead to inaccurately labeled microbial taxa and ultimately lead to privacy concerns as more human genome data is collected. PMID:25926546

  11. Production of bioavailable and refractory dissolved organic matter by coastal heterotrophic microbial populations

    Science.gov (United States)

    Lønborg, Christian; Álvarez-Salgado, Xosé A.; Davidson, Keith; Miller, Axel E. J.

    2009-05-01

    Production of dissolved organic matter (DOM) by heterotrophic microbial communities isolated from Loch Creran (Scotland) was studied in time course incubations in which cells were re-suspended in artificial seawater amended with variable proportions of glucose, ammonium and phosphate. The incubation experiments demonstrated that microheterotrophs released part of the substrate as new DOM, with a production efficiency of 11 ± 1% for DOC, 18 ± 2% for DON and 17 ± 2% for DOP. Estimating the impact of this production in Loch Creran, showed that from 3 ± 1% (DOC) to 72 ± 16% (DOP) of DOM could originate from the heterotrophic microbial community. The produced DOM (PDOM) was both bioavailable (BDOM) and refractory (RDOM). Bioavailability as assessed by the difference between the maximum and the end DOM concentration, was generally higher than found in natural systems, with DOP (73 ± 15%, average ± SD) more bioavailable than DON (70 ± 15%), and DON than DOC (34 ± 13%). The stoichiometry of PDOM was linked to both nutrient uptake and BDOM ratios. Absorption and fluorescence of DOM increased significantly during the incubation time, indicating that microheterotrophs were also a source of coloured DOM (CDOM) and that they produce both bioavailable protein-like and refractory humic-like fluorophores.

  12. 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.

  13. 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.

  14. In Vitro Fermentation Characteristics and Rumen Microbial Population of Diet Supplemented with Saccharomyces cerevisiae and Rumen Microbe Probiotics

    Directory of Open Access Journals (Sweden)

    L. Riyanti

    2016-04-01

    Full Text Available The objective of this study was to select three strains of probiotic Saccharomyces cerevisiae and to evaluate the effect of S. cerevisiae and rumen bacteria isolate (MR4 supplementation and their combination on rumen fermentability and rumen microbial population. Experiment 1 was designed in a 4 x 5 factorial randomized block design with 3 replications. The first factor was S. cerevisiae strain consisted of control treatment (without S. cerevisiae supplementation, NBRC 10217, NRRL Y 567 and NRRL 12618, and the second factor was incubation time consisted of 0, 1, 2, 3, and 4 h. Ration was basal ration for feedlot with forage to concentrate ratio (F:C= 60:40. Dosage of each treatment with S. cerevisiae was 5 x 1010 cfu/kg ration. Experiment 2 was designed in randomized block design with 4 treatments: P0= basal ration of feedlot; P1= P0 + S. cerevisiae; P2= P0 + MR4 isolate (5 x 107 cfu/kg ration; P3= P0 + S. cerevisiae and MR4 isolate. The result of experiment 1 showed that supplementation of S. cerevisiae NRRL 12618 had the highest S. cerevisiae population and increased rumen bacterial population. This strain was selected as probiotic in experiment 2. The result from experiment 2 showed that probiotic supplementation stabilized rumen pH and produced the highest NH3 concentration (P<0.05 and bacterial population (P<0.05. As compared with control, all treatments reduced protozoa population (P<0.05. Combination of S. cerevisiae and MR4 probiotics produced the highest total volatile fatty acids (VFA and isovalerate (P<0.05. It was concluded that strain S. cerevisiae NRRL 12618 had potential as probiotic yeast. Supplementation with this strain increased fermentability, rumen isoacid and decreased A:P ratio. Those abilities could be improved with MR4 rumen isolate probiotic.

  15. Soil microbial biomass and population in response to seasonal variation and age in Gmelina arborea plantations in south-western Nigeria

    Institute of Scientific and Technical Information of China (English)

    Jonathan C.Onyekwelu

    2012-01-01

    Abstract: We investigated the Effects of plantation development,seasons,and soil depth on soil microbial indices in Gmelina arborea plantations in south-western Nigeria.Soil samples were obtained from the soil depths of 0-15 and 15-30 cm from plantations of six different ages during the rainy season,dry seasons,and their transitions.We used plate count and fumigation-extraction methods to determine microbe population and microbial biomass carbon (MB-C) and nitrogen (MB-N),respectively.Plantation age did not affect microbial indices,implying a non-significant effect of plantation development on microbial communities.It could also imply that soil microbial indices had already stabilized in the sampled plantations.Seasonal variation and soil depth had significant effects on microbial indices.At 0-15 cm soil depth,mean MB-C increased from 50.74 μg·g-1 during the peak of the dry season (i.e.March) to 99.58 μg·g-1 during the peak of the rainy season (i.e.September),while it increased from 36.22 μg·g-1 to 75.31 μg·g-1 at 15-30 cm soil depth between the same seasonal periods.Bacteria populations and MB-N showed similar increasing trends.Correlations.between MB-C,MB-N,microbe populations,and rainfall were positive and linear.Significantly higher microbial activities took place in the plantations during the rainy season,increased with soil wetness,and decreased at greater soil depth.

  16. Genetic diversity and population structure of Pisum sativum accessions for marker-trait association of lipid content

    Directory of Open Access Journals (Sweden)

    Sajjad Ahmad

    2015-06-01

    Full Text Available Field pea (Pisum sativum L. is an important protein-rich pulse crop produced globally. Increasing the lipid content of Pisum seeds through conventional and contemporary molecular breeding tools may bring added value to the crop. However, knowledge about genetic diversity and lipid content in field pea is limited. An understanding of genetic diversity and population structure in diverse germplasm is important and a prerequisite for genetic dissection of complex characteristics and marker-trait associations. Fifty polymorphic microsatellite markers detecting a total of 207 alleles were used to obtain information on genetic diversity, population structure and marker-trait associations. Cluster analysis was performed using UPGMA to construct a dendrogram from a pairwise similarity matrix. Pea genotypes were divided into five major clusters. A model-based population structure analysis divided the pea accessions into four groups. Percentage lipid content in 35 diverse pea accessions was used to find potential associations with the SSR markers. Markers AD73, D21, and AA5 were significantly associated with lipid content using a mixed linear model (MLM taking population structure (Q and relative kinship (K into account. The results of this preliminary study suggested that the population could be used for marker-trait association mapping studies.

  17. Genetic diversity and population structure of Pisum sativum accessions for marker-trait association of lipid content

    Institute of Scientific and Technical Information of China (English)

    Sajjad; Ahmad; Simerjeet; Kaur; Neil; Dylan; Lamb-Palmer; Mark; Lefsrud; Jaswinder; Singh

    2015-01-01

    Field pea(Pisum sativum L.) is an important protein-rich pulse crop produced globally. Increasing the lipid content of Pisum seeds through conventional and contemporary molecular breeding tools may bring added value to the crop. However, knowledge about genetic diversity and lipid content in field pea is limited. An understanding of genetic diversity and population structure in diverse germplasm is important and a prerequisite for genetic dissection of complex characteristics and marker-trait associations. Fifty polymorphic microsatellite markers detecting a total of 207 alleles were used to obtain information on genetic diversity, population structure and marker-trait associations. Cluster analysis was performed using UPGMA to construct a dendrogram from a pairwise similarity matrix. Pea genotypes were divided into five major clusters. A model-based population structure analysis divided the pea accessions into four groups. Percentage lipid content in 35 diverse pea accessions was used to find potential associations with the SSR markers. Markers AD73, D21, and AA5 were significantly associated with lipid content using a mixed linear model(MLM) taking population structure(Q) and relative kinship(K) into account. The results of this preliminary study suggested that the population could be used for marker-trait association mapping studies.

  18. The effect of secondary compounds on the rumen microbial population structure measured by 16S rRNA and 18S rRNA

    International Nuclear Information System (INIS)

    Full text: Plant secondary compounds in the forages have an important role in determining forage quality. A method for evaluating their effects on microbial population structure was carried out using the in vitro gas syringe system followed by extraction of RNA and gel separation of 16S rRNA and 18S rRNA. Quantification of 16S rRNA and 18S rRNA bands indicated the prokaryote and eukaryote populations, respectively. Five types of plant materials, i.e. Nothopanax scutellarium (Mangkokan) leaves, Morinda citrifolia (Mengkudu) fruit, Sapindus rarak (lerak) fruit and two types of Sesbania sesban leaves (hgh saponin and low saponin) were tested and Pennisetum purpureum (rumput gajah, Indonesian name) was used as a control roughage. Presence of saponin in these plant materials was determined qualitatively by thin layer chromatography. Eukaryote population was found to be significantly affected by the above plant materials. Both types of S. sesban leaves caused total elimination of eukaryotes. S. rarak reduced both eukaryote and prokaryote populations. The observed inhibition of eukaryote population might be due to the presence of saponin in these plant materials. In another experiment, a methanol extract of S. rarak which contained saponin was included and its effect on in vitro fermentation of P. purpureum was evaluated. The results showed that at higher levels of inclusion of S. rarak methanol extract, eukaroytes were totally eliminated. Comparison was made between microbial mass calculated based on difference between apparent undigested residue and true undigested residue and microbial mass calculations based on 16S rRNA and 18S rRNA. Microbial mass calculated by difference method was much higher than the microbial mass calculated on the basis of 16S rRNA and 18S rRNA. The quantification of RNA can be a useful and rapid technique for an accurate assessment of the effect of new forage materials on the microbial population structure. Other parameters from in vitro

  19. 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.

  20. Lagrangian coherent structures are associated with fluctuations in airborne microbial populations

    Science.gov (United States)

    Tallapragada, P.; Ross, S. D.; Schmale, D. G.

    2011-09-01

    Many microorganisms are advected in the lower atmosphere from one habitat to another with scales of motion being hundreds to thousands of kilometers. The concentration of these microbes in the lower atmosphere at a single geographic location can show rapid temporal changes. We used autonomous unmanned aerial vehicles equipped with microbe-sampling devices to collect fungi in the genus Fusarium 100 m above ground level at a single sampling location in Blacksburg, Virginia, USA. Some Fusarium species are important plant and animal pathogens, others saprophytes, and still others are producers of dangerous toxins. We correlated punctuated changes in the concentration of Fusarium to the movement of atmospheric transport barriers identified as finite-time Lyapunov exponent-based Lagrangian coherent structures (LCSs). An analysis of the finite-time Lyapunov exponent field for periods surrounding 73 individual flight collections of Fusarium showed a relationship between punctuated changes in concentrations of Fusarium and the passage times of LCSs, particularly repelling LCSs. This work has implications for understanding the atmospheric transport of invasive microbial species into previously unexposed regions and may contribute to information systems for pest management and disease control in the future.

  1. Impact of demographics on human gut microbial diversity in a US Midwest population.

    Science.gov (United States)

    Chen, Jun; Ryu, Euijung; Hathcock, Matthew; Ballman, Karla; Chia, Nicholas; Olson, Janet E; Nelson, Heidi

    2016-01-01

    The clinical utility of microbiome biomarkers depends on the reliable and reproducible nature of comparative results. Underappreciation of the variation associated with common demographic, health, and behavioral factors may confound associations of interest and generate false positives. Here, we present the Midwestern Reference Panel (MWRP), a resource for comparative gut microbiome studies conducted in the Midwestern United States. We analyzed the relationships between demographic and health behavior-related factors and the microbiota in this cohort, and estimated their effect sizes. Most variables investigated were associated with the gut microbiota. Specifically, body mass index (BMI), race, sex, and alcohol use were significantly associated with microbial β-diversity (P diversity (P < 0.05, species richness). Tobacco use showed a trend toward association with the microbiota (P < 0.1, unweighted UniFrac). The effect sizes of the associations, as quantified by adjusted R(2) values based on unweighted UniFrac distances, were small (< 1% for all variables), indicating that these factors explain only a small percentage of overall microbiota variability. Nevertheless, the significant associations between these variables and the gut microbiota suggest that they could still be potential confounders in comparative studies and that controlling for these variables in study design, which is the main objective of the MWRP, is important for increasing reproducibility in comparative microbiome studies. PMID:26839739

  2. Identification of the microbial population found in water sources in and around San Salvador Island, Bahamas

    Directory of Open Access Journals (Sweden)

    Pelletier, Michel

    2014-10-01

    Full Text Available San Salvador Island in The Bahamas is home to approximately 1,200 people, and a popular vacation destination. In order to expand our knowledge of the bacterial population found on and around the island, and to assess possible health risks, we analyzed and identified the cultivable bacterial population found in several lakes and ponds throughout the island. The sites tested were located on the northern, north-eastern, eastern, and western districts, as well as one lake located inland. Ten sites with varying salinity, levels of oxygen, visibility, and distance from the ocean were analyzed. The nature of the bacteria present in these sites was identified by microscopy, as well as a series of biochemical tests based on bacterial metabolism. Seven bacterial species, predominantly from the genera Staphylococcus and Klebsiella were identified. Most bacteria identified are part of the normal microbiota of the skin and the gastro-intestinal tract of human and mammals, and should not be considered a danger for the health of the majority of the population and tourists of the island. We also isolated bacteria capable of fixing atmospheric nitrogen, a hallmark of marine bacterial populations. Overall, this study enabled us to add to the repertoire of bacterial species isolated and identified in the diverse marine environments found on San Salvador Island.

  3. Analysis of Genetic Diversity and Population Structure of Sesame Accessions from Africa and Asia as Major Centers of Its Cultivation

    Directory of Open Access Journals (Sweden)

    Komivi Dossa

    2016-04-01

    Full Text Available Sesame is an important oil crop widely cultivated in Africa and Asia. Understanding the genetic diversity of accessions from these continents is critical to designing breeding methods and for additional collection of sesame germplasm. To determine the genetic diversity in relation to geographical regions, 96 sesame accessions collected from 22 countries distributed over six geographic regions in Africa and Asia were genotyped using 33 polymorphic SSR markers. Large genetic variability was found within the germplasm collection. The total number of alleles was 137, averaging 4.15 alleles per locus. The accessions from Asia displayed more diversity than those from Africa. Accessions from Southern Asia (SAs, Eastern Asia (EAs, and Western Africa (WAf were highly diversified, while those from Western Asia (WAs, Northern Africa (NAf, and Southeastern Africa (SAf had the lowest diversity. The analysis of molecular variance revealed that more than 44% of the genetic variance was due to diversity among geographic regions. Five subpopulations, including three in Asia and two in Africa, were cross-identified through phylogenetic, PCA, and STRUCTURE analyses. Most accessions clustered in the same population based on their geographical origins. Our results provide technical guidance for efficient management of sesame genetic resources in breeding programs and further collection of sesame germplasm from these different regions.

  4. Effects of chestnut tannins and coconut oil on growth performance, methane emission, ruminal fermentation, and microbial populations in sheep.

    Science.gov (United States)

    Liu, H; Vaddella, V; Zhou, D

    2011-12-01

    This study was conducted to evaluate the effects of chestnut tannins (CT) and coconut oil (CO) on growth performance, methane (CH₄) emission, ruminal fermentation, and microbial populations in sheep. A total of 48 Rideau Arcott sheep (average body weight 31.5±1.97 kg, 16 wk old) were randomly assigned into 6 treatment groups in a 3 × 2 factorial design, with CT and CO as the main effects (8 sheep per group). The treatments were control diet (CTR), 10 or 30 g of CT/kg of diet (CT10 and CT30), 25 g of CO/kg of concentrate (CO25), and 10 or 30 g of CT/kg of diet+25 g of CO/kg of concentrate (CT10CO25 and CT30CO25). After the feeding trial (60 d), all sheep were moved to respiratory chambers to measure CH₄ emission. After CH₄ emission measurements, all sheep were slaughtered to obtain rumen fluid samples. Results showed that the addition of CT, CO, and CT+CO had no significant effects on growth performance of sheep but reduced CH₄ emission. Addition of CT reduced the NH₃-N concentration in rumen fluid in CT30. Addition of CO decreased the concentration of total volatile fatty acids in rumen fluid. No significant differences were observed in pH and molar proportion of volatile fatty acids among treatments. Addition of CT, CO, and CT+CO significantly decreased methanogen and protozoa populations. Moreover, CO decreased counts of Fibrobacter succinogenes. No significant differences were observed in populations of fungi, Ruminococcus flavefaciens, or Ruminococcus albus among treatments. In conclusion, supplementation of CT and CO seemed to be a feasible means of decreasing emissions of CH₄ from sheep by reduction of methanogen and protozoa populations with no negative effect on growth performance.

  5. Influence of Organic Manures (Biofertilizers on Soil Microbial Population in the Rhizosphere of Mulberry (Morus Indica L.

    Directory of Open Access Journals (Sweden)

    L. Christilda Louis Mary

    2015-03-01

    Full Text Available The effect of different kinds of organic manures on soil microbial population and mulberry production was assessed. A field experiment wascarried out at Periyar EVR College, Tamil Nadu, India in basic soil to study the influence of organic manures on soil bacterial population andmulberry production. The 4 groups of mulberry plants of MR2 variety were biofertilized with FYM, Azospirillum, Phosphobacteria andVermicompost respectively. The biofertilizers lodged bacteria on the rhizosphere of mulberry plants. When the root microorganism areanalyzed Farm yard manure biofertilized mulberry plant root tips had Gluconacobacter diazotrophicus, Bacillus pumilus, Pseudomonas putida,Bacillus coagulans, Bacillus sonorensis, Azotobacter chrococcum; Azospirillum biofertilized mulberry plants root tips had Bacillus coaculans,Azotobactor chrococcum, Azotobactor vinelandii, Bacillus subtilis and Azospirillum brasilense. Phosphobacteria biofertilized mulberry plantroot tips had Pseudomonas putida, Bacillus stearothermophilus, Brevibacillus borslelansis and Streptomycies thermonitrificans andvermicompost biofertilized mulberry plant root tips had lodged bacterias like Bacillus megaterium, Bacillus subtilis, Gluconacobacterdiazotrophicus, Pseudomonas putida, Azotobacter chrococcum, Azotobacter vinelandi, Bacillus stearothermophilus, Brevibacillus borslelansisand Bacillus sonorensis. Microbiology work reveals luxuriant growth of bacteria in all the biofertizer treated rhizosphere in the order FYM

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

    Science.gov (United States)

    Kim, Eun T; Guan, Le Luo; Lee, Shin J; Lee, Sang M; Lee, Sang S; Lee, Il D; Lee, Su K; Lee, Sung S

    2015-04-01

    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 (pPunica, 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. PMID:25656200

  7. Wetland restoration and methanogenesis: the activity of microbial populations and competition for substrates at different temperatures

    Directory of Open Access Journals (Sweden)

    V. Jerman

    2009-02-01

    Full Text Available Ljubljana marsh in Slovenia is a 16 000 ha area of partly drained fen, intended to be flooded to restore its ecological functions. The resultant water-logging may create anoxic conditions, eventually stimulating production and emission of methane, the most important greenhouse gas next to carbon dioxide. We examined the upper layer (~30 cm of Ljubljana marsh soil for microbial processes that would predominate in water-saturated conditions, focusing on the potential for iron reduction, carbon mineralization (CO2 and CH4 production, and methane emission. Methane emission from water-saturated microcosms was near minimum detectable levels even after extended periods of flooding (>5 months. Methane production in anoxic soil slurries started only after a lag period and was inversely related to iron reduction, which suggested that iron reduction out-competed methanogenesis for electron donors, such as H2 and acetate. Methane production was observed only in samples incubated at 14–38°C. At the beginning of methanogenesis, acetoclastic methanogenesis dominated. In accordance with the preferred substrate, most (91% mcrA (encoding the methyl coenzyme-M reductase, a key gene in methanogenesis clone sequences could be affiliated to the acetoclastic genus Methanosarcina. No methanogens were detected in the original soil. However, a diverse community of iron-reducing Geobacteraceae was found. Our results suggest that methane emission can remain transient and low if water-table fluctuations allow re-oxidation of ferrous iron, sustaining iron reduction as the most important process in terminal carbon mineralization.

  8. Wetland restoration and methanogenesis: the activity of microbial populations and competition for substrates at different temperatures

    Directory of Open Access Journals (Sweden)

    V. Jerman

    2009-06-01

    Full Text Available Ljubljana marsh in Slovenia is a 16 000 ha area of partly drained fen, intended to be flooded to restore its ecological functions. The resultant water-logging may create anoxic conditions, eventually stimulating production and emission of methane, the most important greenhouse gas next to carbon dioxide. We examined the upper layer (~30 cm of Ljubljana marsh soil for microbial processes that would predominate in water-saturated conditions, focusing on the potential for iron reduction, carbon mineralization (CO2 and CH4 production, and methane emission. Methane emission from water-saturated microcosms was near minimum detectable levels even after extended periods of flooding (>5 months. Methane production in anoxic soil slurries started only after a lag period of 84 d at 15°C and a minimum of 7 d at 37°C, the optimum temperature for methanogenesis. This lag was inversely related to iron reduction, which suggested that iron reduction out-competed methanogenesis for electron donors, such as H2 and acetate. Methane production was observed only in samples incubated at 14–38°C. At the beginning of methanogenesis, acetoclastic methanogenesis dominated. In accordance with the preferred substrate, most (91% mcrA (encoding the methyl coenzyme-M reductase, a key gene in methanogenesis clone sequences could be affiliated to the acetoclastic genus Methanosarcina. No methanogens were detected in the original soil. However, a diverse community of iron-reducing Geobacteraceae was found. Our results suggest that methane emission can remain transient and low if water-table fluctuations allow re-oxidation of ferrous iron, sustaining iron reduction as the most important process in terminal carbon mineralization.

  9. Reduction of Microbial Population in Cheese Whey by UV in a Single and Series Conventional Reactors

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2006-01-01

    Full Text Available In this study, the effectiveness of two conventional UV reactors in series for the online sterilization of cheese whey was compared to that of a single conventional reactor. The single reactor and the two reactor series were tested at eleven flow rates (5, 10, 15, 20, 25, 30, 35, 40, 50, 60 and 70 mL min-1 and five flow rates, (35, 40, 50, 60, 70 mL min-1, respectively. 100% destruction efficiency could not be achieved in the single reactor. When two reactors were connected in series, the destruction efficiency reached 100% at the flow rate of 35 mL min-1 and lasted for 25 min. The temperature of the effluent decreased with the increase in flow rate in both systems. The rate of microbial destruction in the single reactor and the two reactor series was described by an exponential equation. The maximum effluent temperatures in the single reactor and the two reactor series were 45.8 and 36.0°C, respectively. The flow in both reactors was laminar (Re=1.39 at 5mL min-1 and Re= 20.10 at 70 mL min-1. Visual observation revealed less fouling on the UV lamps of two reactor series than the single reactor. A different design in which there is no contact between the liquid and the UV lamp should be investigated. The quartz sleeve could also be replaced with fluropolymer coiled tube around the UV lamp. The smooth surface of the fluropolymer would reduce scaling and extend the effective operating time.

  10. Acinetobacter, Aeromonas, and Trichococcus populations dominate the microbial community within urban sewer infrastructure

    OpenAIRE

    VandeWalle, J. L.; Goetz, G.W.; Huse, S.M.; Morrison, H. G.; Sogin, M L; Hoffmann, R.G.; Yan, K.; McLellan, S.L.

    2012-01-01

    We evaluated the population structure and temporal dynamics of the dominant community members within sewage influent from two wastewater treatment plants (WWTPs) in Milwaukee, WI. We generated >1.1M bacterial pyrotag sequences from the V6 hypervariable region of 16S rRNA genes from 38 influent samples and two samples taken upstream in the sanitary sewer system. Only a small fraction of pyrotags from influent samples (~15%) matched sequences from human fecal samples. The fecal components of th...

  11. 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

  12. Shedding light on microbial predator-prey population dynamics using a quantitative bioluminescence assay.

    Science.gov (United States)

    Im, Hansol; Kim, Dasol; Ghim, Cheol-Min; Mitchell, Robert J

    2014-01-01

    This study assessed the dynamics of predation by Bdellovibrio bacteriovorus HD 100. Predation tests with two different bioluminescent strains of Escherichia coli, one expressing a heat-labile bacterial luciferase and the other a heat-stable form, showed near identical losses from both, indicating that protein expression and stability are not responsible for the "shutting-off" of the prey bioluminescence (BL). Furthermore, it was found that the loss in the prey BL was not proportional with the predator-to-prey ratio (PPR), with significantly greater losses seen as this value was increased. This suggests that other factors also play a role in lowering the prey BL. The loss in BL, however, was very consistent within nine independent experiments to the point that we were able to reliably estimate the predator numbers within only 1 h when present at a PPR of 6 or higher, Using a fluorescent prey, we found that premature lysis of the prey occurs at a significant level and was more prominent as the PPR ratio increased. Based upon the supernatant fluorescent signal, even a relatively low PPR of 10-20 led to approximately 5% of the prey population being prematurely lysed within 1 h, while a PPR of 90 led to nearly 15% lysis. Consequently, we developed a modified Lotka-Volterra predator-prey model that accounted for this lysis and is able to reliably estimate the prey and bdelloplast populations for a wide range of PPRs. PMID:24272279

  13. Degradation of chlorpyrifos alone and in combination with chlorothalonil and their effects on soil microbial populations

    Institute of Scientific and Technical Information of China (English)

    CHU Xiaoqiang; FANG Hua; PAN Xuedong; WANG Xiao; SHAN Min; FENG Bo; YU Yunlong

    2008-01-01

    In practice, pesticides are usually applied simultaneously or one after another for crop protection, and this type of pesticide application often leads to a combined contamination of pesticide residues in the soil environment. A laboratory study was conducted to investigate the influence of chlorothalonil on chlorpyrifos degradation and its effects on soil bacterial, fungal, and actinomycete populations. Under the experimental conditions here, the half-lives of chlorpyrifos alone, and in combination with chlorothalonil, at the recommended and double dosages, were measured to be 3.24, 2.77, and 2.63 d, respectively. Chlorpyrifos degradation was not significantly altered by its combination with chlorothalonil. However, the inhibitory effect of chlorpyrifos on soil microorganisms was increased by its combination with chlorothalonil, and the increase was related to the levels of chlorothalonil added. Compared to those in the controls, the populations of bacteria, fungi, and actinomycetes were significantly reduced by 44.1%, 61.1%, and 72.8%, respectively, on the first day after treatment (DAT) by chlorpyrifos alone. With the addition of chlorothalonil, the inhibition was increased to 55.2%, 79.3%, and 85.8% at the recommended dosage, and 86.0%, 94.1%, and 90.8% at the double dosage, at one DAT, respectively. The results suggested that combined effects should be taken into account to assess the actual impacts of pesticide applications.

  14. Relationships Between Aquifer Properties and Microbial Populations in the Borden Aquifer

    DEFF Research Database (Denmark)

    Barbaro, Susan Elizabeth; Albrechtsen, Hans-Jørgen; Jensen, Bjorn K.;

    1994-01-01

    , electron transport system (ETS) activity, dissolved oxygen (DO), dissolved organic carbon (DOC), weight fraction of organic carbon (FOC), and hydraulic conductivity (K) were determined for contiguous samples of aquifer material removed at 10.0-cm intervals from the 9 cores. Viable cell counts (0-10-4 cfu...... microbiological and geologic data collected in this study suggests that, in conjunction with low dissolved oxygen, the naturally occurring carbon may be unsuitable to support large numbers of microorganisms. Similarly, an increase in the production of INT-for when aquifer material was amended with nitrogen...... activities were found to be predominantly correlated with depth and dissolved oxygen. Evaluation of these results revealed an oxygen threshold level, occurring at approximately 3.0 mg/L, below which bacterial populations isolated in this study were less able to proliferate. Further evaluation of the...

  15. Immigrant mothers and access to prenatal care: evidence from a regional population study in Italy

    OpenAIRE

    Chiavarini, Manuela; Lanari, Donatella; Minelli, Liliana; Pieroni, Luca; Salmasi, Luca

    2016-01-01

    Objectives We addressed the question of whether use of adequate prenatal care differs between foreign-born and Italian mothers and estimated the extent to which unobservable characteristics bias results. Setting This study is on primary care and especially on adequate access to prenatal healthcare services by immigrant mothers. Participants Approximately 37 000 mothers of both Italian and foreign nationality were studied. Data were obtained from the Standard Certificate of Live Birth between ...

  16. Is accessing dental care becoming more difficult? Evidence from Canada's middle-income population.

    Directory of Open Access Journals (Sweden)

    Chantel Ramraj

    Full Text Available OBJECTIVE: To explore trends in access to dental care among middle-income Canadians. METHODS: A secondary data analysis of six Canadian surveys that collected information on dental insurance coverage, cost-barriers to dental care, and out-of-pocket expenditures for dental care was conducted for select years from 1978 to 2009. Descriptive analyses were used to outline and compare trends among middle-income Canadians with other levels of income as well as national averages. RESULTS: By 2009, middle-income Canadians had the lowest levels of dental insurance coverage (48.7% compared to all other income groups. They reported the greatest increase in cost-barriers to dental care, from 12.6% in 1996 to 34.1% by 2009. Middle-income Canadians had the largest rise in out-of-pocket expenditures for dental care since 1978. CONCLUSIONS: This study suggests that affordability issues in accessing dental care are no longer just a problem for the lowest income groups in Canada, but are now impacting middle-income earners as a consequence of their lack of, or decreased access to, comprehensive dental insurance.

  17. Determinants of Treatment Access in a Population-based Cohort of HIV-positive Men and Women Living in Argentina

    Directory of Open Access Journals (Sweden)

    Zala Carlos

    2008-04-01

    Full Text Available Abstract Objective To report emerging data on the use of highly active antiretroviral therapy (HAART in Argentina by assessing patterns of HAART access and late vs early treatment initiation in a population-based cohort of adults infected with HIV type-1. Design The Prospective Study on the Use and Monitoring of Antiretroviral Therapy (PUMA is a study of 883 HIV-positive individuals enrolled in the Argentinean drug treatment program. Individuals were 16 years of age and older and were recruited from 10 clinics across Argentina. Methods Sociodemographic and clinical characteristics were examined using contingency tables (Pearson chi-square test and Fisher exact test for categoric variables and Wilcoxon rank-sum test for continuous variables. To analyze time to initiation of HAART we used Kaplan-Meier methods and Cox regression. Results Patients who initiated HAART were more likely to be older, have an AIDS-defining illness, be an injection drug user (IDU, have a lower median CD4 cell count, have a higher median viral load, and be less likely to be men who have sex with men (MSM. In multivariate analysis, AIDS-defining illness and plasma viral load were significantly associated with time to starting therapy. Patients who received late access were more likely to be diagnosed with AIDS and have higher median plasma viral loads than those receiving early access. Conclusion Our results indicate that despite free availability of treatment, monitoring, and care in Argentina, a significant proportion of men and women are accessing HAART late in the course of HIV disease. Further characterization of the HIV-positive population will allow for a more comprehensive evaluation of the impact of HAART within the Argentinean drug treatment program.

  18. Microbial infections in a declining wild turkey population in Texas (USA)

    Science.gov (United States)

    Rocke, T.E.; Yuill, Thomas M.

    1987-01-01

    A survey was conducted at 5 locations in Texas for avian pathogens that might adversely affect wild turkey (Meleagris gallopavo) productivity and survival. At 1 site, the Rob and Bessie Welder Wildlife Refuge (WWR), turkeys have declined precipitously in recent years. During the winters of 1983-85, 442 wild turkeys were caught with cannon and drop nets, 161 of these on WWR. Blood samples were drawn for serologic evaluation, and cloacal and tracheal swabs were collected for isolation attempts. Salmonella spp. bacteria, Newcastle disease virus (NDV), and avian influenza virus (AIV) were not detected in any samples tested. Serologic tests for antibodies to NDV and AIV also were negative. Many mycoplasma isolates were recovered from turkeys from every location. Characterization of these isolates indicated that several species were present. None were species typically associated with mycoplasmosis in domestic turkeys, such as Mycoplasma gallisepticum (MG), M. meleagridis (MM), or M. synoviae (MS), although antibodies to these pathogens were detected in turkeys at every location sampled. There was no evidence to link any of these disease causing agents to the decline observed in the population of wild turkeys on the WWR.

  19. Unravelling the interactions among microbial populations found in activated sludge during biofilm formation.

    Science.gov (United States)

    Liébana, Raquel; Arregui, Lucía; Santos, Antonio; Murciano, Antonio; Marquina, Domingo; Serrano, Susana

    2016-09-01

    Microorganisms colonize surfaces and develop biofilms through interactions that are not yet thoroughly understood, with important implications for water and wastewater systems. This study investigated the interactions between N-acyl homoserine lactone (AHL)-producing bacteria, yeasts and protists, and their contribution to biofilm development. Sixty-one bacterial strains were isolated from activated sludge and screened for AHL production, with Aeromonas sp. found to be the dominant AHL producer. Shewanella xiamenensis, Aeromonas allosaccharophila, Acinetobacter junii and Pseudomonas aeruginosa recorded the highest adherence capabilities, with S. xiamenensis being the most effective in surface colonization. Additionally, highly significant interactions (i.e. synergic or antagonistic) were described for dual and multistrain mixtures of bacterial strains (P. aeruginosa, S. xiamenensis, A. junii and Pseudomonas stutzeri), as well as for strongly adherent bacteria co-cultured with yeasts. In this last case, the adhered biomass in co-cultures was lower than the monospecific biofilms of bacteria and yeast, with biofilm observations by microscopy suggesting that bacteria had an antagonist effect on the whole or part of the yeast population. Finally, protist predation by Euplotes sp. and Paramecium sp. on Aeromonas hydrophila biofilms not only failed to reduce biofilm formation, but also recorded unexpected results leading to the development of aggregates of high density and complexity. PMID:27306553

  20. Impact of Fungicide Mancozeb at Different Application Rates on Soil Microbial Populations, Soil Biological Processes, and Enzyme Activities in Soil

    Directory of Open Access Journals (Sweden)

    Abhishek Walia

    2014-01-01

    Full Text Available The use of fungicides is the continuous exercise particularly in orchard crops where fungal diseases, such as white root rot, have the potential to destroy horticultural crops rendering them unsaleable. In view of above problem, the present study examines the effect of different concentrations of mancozeb (0–2000 ppm at different incubation periods for their harmful side effects on various microbiological processes, soil microflora, and soil enzymes in alluvial soil (pH 6.8 collected from apple orchards of Shimla in Himachal Pradesh (India. Low concentrations of mancozeb were found to be deleterious towards fungal and actinomycetes population while higher concentrations (1000 and 2000 ppm were found to be detrimental to soil bacteria. Mancozeb impaired the process of ammonification and nitrification. Similar results were observed for nitrifying and ammonifying bacteria. Phosphorus solubilization was increased by higher concentration of mancozeb, that is, 250 ppm and above. In unamended soil, microbial biomass carbon and carbon mineralization were adversely affected by mancozeb. Soil enzymes, that is, amylase, invertase, and phosphatase showed adverse and disruptive effect when mancozeb used was above 10 ppm in unamended soil. These results conclude that, to lessen the harmful effects in soil biological processes caused by this fungicide, addition of higher amount of nitrogen based fertilizers is required.

  1. Effect of aeration on stabilization of organic solid waste and microbial population dynamics in lab-scale landfill bioreactors.

    Science.gov (United States)

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

    2008-11-01

    This study investigated microbial population dynamics and performance in lab-scale conventional, anaerobic, and aerobic landfill bioreactors specialized for high-organic wastes. Each reactor (2.35 l) was loaded with 1.5 kg of organic solid waste made of sludge cake, dry dog food, and wood chips. The conventional reactor was operated without leachate recirculation and aeration, but the other reactors used leachate recirculation at 200 ml/d and without aeration (anaerobic bioreactor) or with aeration at 2 l/min (aerobic bioreactor). The respective final waste volumes on day 138 of the conventional, anaerobic, and aerobic reactors were approximately 75%, 65%, and 60% of the initial volumes. Leachate recirculation in the anaerobic bioreactor accelerated biochemical reactions and promoted methane production. However, leachate from the anaerobic bioreactor showed TOC and NH(4)(+)-N concentrations that were as high as those of the conventional reactor. Aeration lowered leachate production and methane concentration and decreased organic matter in solid waste and leachate. Furthermore, the MPN value of amoA gene reached 10(5) MPN-copies/g-dry in the aerobic bioreactor, where nitrogen was removed from organic solid waste and leachate. During the first 72 d, the aerobic bioreactor's MPN value of fungal 18S rDNA was the highest among reactors, but it decreased gradually. All reactors showed similar MPN values of eubacterial 16S rDNA, nirS, and nirK. PMID:19111637

  2. 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

  3. Effects of Seasonal Changes (The Spring and The Autumn on Microbial Population of the Surface Soils Planted the Various Tree Species

    Directory of Open Access Journals (Sweden)

    Hasan Hüseyin Koç

    2014-02-01

    Full Text Available Microbial population of soil and its structure is affected with chemical and biological changes such as plant-root secretions. Upper layer of the soil is exposed to mixture of stems, fruiting bodies and leaves of trees. Seven trees growing at same area were chosen. Their upper layers of the soil were collected from depth 5-10 cm as samples in spring and autumn. Their microbial populations were investigated in order to determine in terms of climate changes. In order to determine the number of the total microorganisms, gram-negative bacteria and spore-forming bacteria (cfu/g were used by the serial dilution techniques. As a result, the highest numbers of microorganisms from the soil of the apple tree were determined as the total microbial count in the autumn, although the lowest number of microorganisms was obtained from the soil of the pine tree. However, the number of the gram-negative bacteria was the highest in the soil of linden tree, although the number of gram negative bacteria was the lowest in the soil of apricot, mulberry and apple trees. For spore - forming bacterium, the highest number from the mulberry soil and the lowest number from the linden tree have been obtained. In the spring, the highest numbers of microorganisms from the soil of the apple tree were obtained as the total microbial count, although the lowest number of microorganisms was obtained from the soil of the apricot tree. For the number of the gram-negative bacteria was the highest in the soil of walnut tree, although the number of gram negative bacteria was the lowest in the soil of apricot trees. However spore - forming bacterium, the highest number from the soil of the poplar tree and the lowest number from the mulberry tree have been obtained. In general, the rich diversity of the microbial population was shown morphologically in autumn.

  4. A household panel as a tool for cost-effective health-related population surveys: validity of the "Healthcare Access Panel"

    OpenAIRE

    Potthoff, Peter; Heinemann, Lothar A. J.; Güther, Bernd

    2004-01-01

    Background: Random sample surveys of the population are time consuming and expensive, particularly if international sampling is planned. Method: The Healthcare Access Panel was developed as an alternative to face to face or telephone health survey interviews to estimate prevalence or even incidence rates of health-relevant variables in the population. It is the objective of this paper to demonstrate the validity of health-related data obtained with the Healthcare Access Panel compared with re...

  5. Evaluation of reactive oxygen species generating AirOcare system for reducing airborne microbial populations in a meat processing plant

    Science.gov (United States)

    The microbial contamination of meat and meat products is of continuing concern to the meat industry and regulatory agencies. Air has been established as a source of microbial contamination in slaughter and processing facilities. The objective of this research was to determine the efficacy of reactiv...

  6. Demand for and Accessibility to Reproductive Health Service of Urban Floating Population

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The demand for knowledge of productive health and the current status of productive health services provided by relevant governmental institutions were qualitatively and quantitatively studied. The study identified the key factors that influenced the demand for the productive health services and results of the services. It also discussed the effective approaches to control, planning and sustainable development of the reproductive health services for the floating populations.

  7. Is Access Sufficient?: An Examination of the Effects of the MedShare Program to Expand Access to Prescription Drugs for Indigent Populations

    Science.gov (United States)

    Shaw, Thomas; Carrozza, Mark

    2008-01-01

    We conduct an evaluation of MedShare, a program designed to enhance access to prescription drugs for indigent patients in the Greater Cincinnati area. The program expands access to drugs by providing subsidies to reduce the costs paid by patients for their prescriptions. The assumption is that by expanding access to prescription drugs, participant…

  8. How to Show the Real Microbial Biodiversity? A Comparison of Seven DNA Extraction Methods for Bacterial Population Analyses in Matrices Containing Highly Charged Natural Nanoparticles

    OpenAIRE

    Rene Kaden; Peter Krolla-Sidenstein

    2015-01-01

    A DNA extraction that comprises the DNA of all available taxa in an ecosystem is an essential step in population analysis, especially for next generation sequencing applications. Many nanoparticles as well as naturally occurring clay minerals contain charged surfaces or edges that capture negatively charged DNA molecules after cell lysis within DNA extraction. Depending on the methodology of DNA extraction, this phenomenon causes a shift in detection of microbial taxa in ecosystems and a poss...

  9. Improved Yield of High Molecular Weight DNA Coincides with Increased Microbial Diversity Access from Iron Oxide Cemented Sub-Surface Clay Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, Jr., Richard Ashley [ORNL; Moberly, James G [ORNL; Shakya, Migun [ORNL; Vishnivetskaya, T. [University of Tennessee, Knoxville (UTK); Elias, Dwayne A [ORNL

    2014-01-01

    Despite more than three decades of progress, efficient nucleic acid extraction from microbial communities has remained difficult, particularly from clay environments. Lysis with concentrated guanidine followed by concentrated sodium phosphate extraction supported DNA and RNA recovery from high iron, low humus content clay. Alterating the extraction pH or using other ionic solutions (Na2SO4 and NH4H2PO4) yielded no detectable nucleic acid. DNA recovered using a lysis solution with 500 mM phosphate buffer (PB) followed by a 1 M PB wash was 15.22 2.33 g DNA/g clay, with most DNA consisting of >20 Kb fragments, compared to 2.46 0.25 g DNA/g clay with the Powerlyzer soil DNA system (MoBio). Increasing [PB] in the lysis reagent coincided with increasing DNA fragment length. Rarefaction plots based on16S rRNA (V1/V3 region) pyrosequencing libraries from A-horizon and clay soils showed an ~80% and ~400% larger accessed diversity compared to a previous grinding protocol or the Powerlyzer soil DNA system, respectively. The observed diversity from the Firmicutes showed the strongest increase with >3-fold more bacterial species recovered using this system. Additionally, some OTU s having more than 100 sequences in these libraries were absent in samples extracted using the PowerLyzer reagents or the previous lysis method.

  10. People living with HIV travel farther to access healthcare: a population-based geographic analysis from rural Uganda

    Directory of Open Access Journals (Sweden)

    Adam N Akullian

    2016-02-01

    Full Text Available Introduction: The availability of specialized HIV services is limited in rural areas of sub-Saharan Africa where the need is the greatest. Where HIV services are available, people living with HIV (PLHIV must overcome large geographic, economic and social barriers to access healthcare. The objective of this study was to understand the unique barriers PLHIV face when accessing healthcare compared with those not living with HIV in a rural area of sub-Saharan Africa with limited availability of healthcare infrastructure. Methods: We conducted a population-based cross-sectional study of 447 heads of household on Bugala Island, Uganda. Multiple linear regression models were used to compare travel time, cost and distance to access healthcare, and log binomial models were used to test for associations between HIV status and access to nearby health services. Results: PLHIV travelled an additional 1.9 km (95% CI (0.6, 3.2 km, p=0.004 to access healthcare compared with those not living with HIV, and they were 56% less likely to access healthcare at the nearest health facility to their residence, so long as that facility lacked antiretroviral therapy (ART services (aRR=0.44, 95% CI (0.24 to 0.83, p=0.011. We found no evidence that PLHIV travelled further for care if the nearest facility supplies ART services (aRR=0.95, 95% CI (0.86 to 1.05, p=0.328. Among those who reported uptake of care at one of two facilities on the island that provides ART (81% of PLHIV and 68% of HIV-negative individuals, PLHIV tended to seek care at a higher tiered facility that provides ART, even when this facility was not their closest facility (30% of PLHIV travelled further than the closest ART facility compared with 16% of HIV-negative individuals, and travelled an additional 2.2 km (p=0.001 to access that facility, relative to HIV-negative individuals (aRR=1.91, 95% CI (1.00 to 3.65, p=0.05. Among PLHIV, residential distance was associated with access to facilities providing

  11. From the Margins to the Spotlight: Diverse Deaf and Hard of Hearing Student Populations and Standardized Assessment Accessibility.

    Science.gov (United States)

    Cawthon, Stephanie

    2015-01-01

    Designing assessments and tests is one of the more challenging aspects of creating an accessible learning environment for students who are deaf or hard of hearing (DHH), particularly for deaf students with a disability (DWD). Standardized assessments are a key mechanism by which the educational system in the United States measures student progress, teacher effectiveness, and the impact of school reform. The diversity of student characteristics within DHH and DWD populations is only now becoming visible in the research literature relating to standardized assessments and their use in large-scale accountability reforms. The purpose of this article is to explore the theoretical frameworks surrounding assessment policy and practice, current research related to standardized assessment and students who are DHH and DWD, and potential implications for practice within both the assessment and instruction contexts. PMID:26497076

  12. Is the Brazilian pharmaceutical policy ensuring population access to essential medicines?

    Directory of Open Access Journals (Sweden)

    Bertoldi Andréa

    2012-03-01

    Full Text Available Abstract Background To evaluate medicine prices, availability and affordability in Brazil, considering the differences across three types of medicines (originator brands, generics and similar medicines and different types of facilities (private pharmacies, public sector pharmacies and “popular pharmacies”. Methods Data on prices and availability of 50 medicines were collected in 56 pharmacies across six cities in Southern Brazil using the World Health Organization / Health Action International methodology. Median prices obtained were divided by international reference prices to derive the median price ratio (MPR. Results In the private sector, prices were 8.6 MPR for similar medicines, 11.3 MRP for generics and 18.7 MRP for originator brands, respectively. Mean availability was 65%, 74% and 48% for originator brands, generics and similar medicines, respectively. In the public sector, mean availability of similar medicines was 2–7 times higher than that of generics. Mean overall availability in the public sector ranged from 68.8% to 81.7%. In “popular pharmacies”, mean availability was greater than 90% in all cities. Conclusions Availability of medicines in the public sector does not meet the challenge of supplying essential medicines to the entire population, as stated in the Brazilian constitution. This has unavoidable repercussions for affordability, particularly amongst the lower socio-economic strata.

  13. Population Of US Practicing Psychiatrists Declined, 2003-13, Which May Help Explain Poor Access To Mental Health Care.

    Science.gov (United States)

    Bishop, Tara F; Seirup, Joanna K; Pincus, Harold Alan; Ross, Joseph S

    2016-07-01

    A large proportion of the US population suffers from mental illness. Limited access to psychiatrists may be a contributor to the underuse of mental health services. We studied changes in the supply of psychiatrists from 2003 to 2013, compared to changes in the supply of primary care physicians and neurologists. During this period the number of practicing psychiatrists declined from 37,968 to 37,889, which represented a 10.2 percent reduction in the median number of psychiatrists per 100,000 residents in hospital referral regions. In contrast, the numbers of primary care physicians and neurologists grew during the study period. These findings may help explain why patients report poor access to mental health care. Future research should explore the impact of the declining psychiatrist supply on patients and investigate new models of care that seek to integrate mental health and primary care or use team-based care that combines the services of psychiatrists and nonphysician providers for individuals with severe mental illnesses. PMID:27385244

  14. Primary care for urban adolescent girls from ethnically diverse populations: foregone care and access to confidential care.

    Science.gov (United States)

    McKee, Diane; Fletcher, Jason

    2006-11-01

    Adolescent girls face unique challenges in health care utilization, which can result in unmet needs. We sought to describe settings of usual care and primary care use, and to identify predictors of foregone care and experience of confidential care in a primarily racial/ethnic minority low-income sample. We conducted an anonymous computer-assisted self-administered survey of 9th-12th grade girls (n=819) in three Bronx public high schools, the majority of whom were Hispanic (69.8%) and Black (21.4%). Most (80%) reported having a usual source of care. Of these, 77.2% had a regular doctor. Those least likely to have a usual source of care were non-U.S. born girls (73.1% vs. 83.1%) and less acculturated girls. Predictors of foregone care in the last year include being sexually active, poor family social support, and low self esteem. Predictors of access to confidential care at last visit were age, self-efficacy for confidential care, having a regular doctor, setting of care, and having had a recent physical exam. Many urban adolescent girls, especially non-U.S. born girls, lack a usual source of care and regular health care provider. Continued attention to reducing both financial and non-financial barriers to care is required to ensure access to and quality of care for diverse populations. PMID:17242529

  15. "Population and poverty: major barriers to food accessibility" -- a panel discussion on civil society and people's participation.

    Science.gov (United States)

    1996-01-01

    This paper summarizes conference statements on poverty and food policies that were made by parliamentary members from Malaysia, the Philippines, and India. These presentations were made after the main panel discussion on barriers to food accessibility. In Malaysia the government adopted a National Agricultural Policy in 1984. This policy encouraged increased productivity, effective use of resources, agricultural credit and incentives, and integrated pest management. Strong support was given to the food processing industry. Poverty was the main reason for food inaccessibility. Through government efforts, poverty was reduced from 16.5% in 1990 to 8.9% in 1995. The Filipino member reported that government efforts had focused on national campaigns to combat hunger and to encourage community participation. The government was forced to implement a national Plan of Action for Food Security due to increased population, environmental degradation, closing land frontiers, and the global economy. The Plan encouraged increases in productivity, price and supply stabilization, maintenance of stocks, and rice subsidies for the poor. Gender concerns were being incorporated into development programs. The Indian member linked food insecurity to world resource problems. He stated that food problems included imbalances between supply and demand, but more importantly inequalities in access to food and differences in nutritional content of food. Populations in developing countries spent a larger proportion of income on food of lesser quality and variety that contributed to nutritional deficiencies, particularly among women and children. Food insecurity was part of the cycle of poverty, hunger, low productivity, and high mortality. Poverty was the primary cause and a major consequence of hunger and chronic food insecurity. Although India increased food productivity, food insecurity remained. Multidisciplinary approaches are needed. PMID:12292317

  16. Mapping socio-environmentally vulnerable populations access and exposure to ecosystem services at the U.S.-Mexico borderlands

    Science.gov (United States)

    Norman, Laura M.; Villarreal, Miguel L.; Lara-Valencia, Francisco; Yuan, Yongping; Nie, Wenming; Wilson, Sylvia; Amaya, Gladys; Sleeter, Rachel

    2012-01-01

    Socio-environmental vulnerable populations are often unrepresented in land-use planning yet have great potential for loss when exposed to changes in ecosystem services. Administrative boundaries, cultural differences, and language barriers increase the disassociation between land-use management and marginalized populations living in the U.S.–Mexico borderlands. This paper describes the development of a Modified Socio-Environmental Vulnerability Index (M-SEVI), using determinants from binational census and neighborhood data that describe levels of education, access to resources, migratory status, housing, and number of dependents, to provide a simplified snapshot of the region's populace that can be used in binational planning efforts. We apply this index at the SCW, located on the border between Arizona, USA and Sonora, Mexico. For comparison, the Soil and Water Assessment Tool is concurrently applied to assess the provision of erosion- and flood control services over a 9-year period. We describe how this coupling of data can form the base for an ecosystem services assessment across political boundaries that can be used by land-use planners. Results reveal potential disparities in environmental risks and burdens throughout the binational watershed in residential districts surrounding and between urban centers. The M-SEVI can be used as an important first step in addressing environmental justice for binational decision-making.

  17. Effects of Neutral Detergent Soluble Fiber and Sucrose Supplementation on Ruminal Fermentation, Microbial Synthesis, and Populations of Ruminal Cellulolytic Bacteria Using the Rumen Simulation Technique (RUSITEC)

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiang-hui; LIU Chan-juan; LI Chao-yun; YAO Jun-hu

    2013-01-01

    We evaluated the effects of neutral detergent soluble fiber (NDSF) and sucrose supplementation on ruminal fermentation, microbial synthesis, and populations of ruminal cellulolytic bacteria using the rumen simulation technique (RUSITEC). The experiment had a 2×2 factorial design with two dosages of sucrose, low (ca. 0.26 g d-1, low-sucrose) and high (ca. 1.01 g d-1, high-sucrose), and two dosages of supplied NDSF, low (1.95 g d-1, low-NDSF) and high (2.70 g d-1, high-NDSF). Interactions between NDSF and sucrose were detected for xylanase activity from solid fraction and apparent disappearance of neutral detergent fiber (NDF) and hemicellulose, with the lowest values observed for high-NDSF and high-sucrose treatment. Supplemental NDSF appeared to increase the molar proportion of acetate and reduce that of butyrate;however, the effects of supplemental sucrose on VFA profiles depended upon NDSF amount. There was a NDSF×sucrose interaction for the production of methane. High-NDSF fermenters had lower ammonia-N production, greater daily N flow of solid-associated microbial pellets and total microorganisms, and greater microbial synthesis efficiency compared with low-NDSF fermenters. Supplementation with NDSF resulted in an increase in 16S rDNA copies of Ruminococcus flavefaciens and a reduction in copies of Ruminococcus albus. Supplementation with sucrose tended to increase the 16S rDNA copies of R. albus from liquid fraction, but did not affect daily total microbial N flow and cellulolytic bacterium populations from solid fraction. These data indicate that the effects of the interaction between NDSF and sugars on ruminal fermentation and fiber digestion should be taken into account in diet formulation. Ruminal fermentation and metabolism of sugars warrant further investigation.

  18. Thick juice degradation: study of the microbial population dynamics and control of the causative flora during storage

    OpenAIRE

    Justé, Annelies

    2008-01-01

    Table of contents Abstract i Samenvatting iii Publications v List of abbreviations vii 1. CURRENT KNOWLEDGE ABOUT SUGAR THICK JUICE PRODUCTION 1 1.1 SUGAR PRODUCTION FROM SUGAR BEETS 2 1.2 THICK JUICE DEGRADATION DURING STORAGE 4 1.3 MICROBIAL COMMUNITY ANALYSIS TECHNIQUES IN FOOD AND FOOD- ASSOCIATED MATRICES 9 1.3.1 Choice of target genes 10 1.3.1.1. Ubiquitously conserved genes 10 1.3.1.2. Functional genes 11 1.3.2 Microbial community analysis tech...

  19. [Health status and access to health services by the population of L'Aquila (Abruzzo Region, Italy) six years after the earthquake].

    Science.gov (United States)

    Altobelli, Emma; Vittorini, Pierpaolo; Leuter, Cinzia; Bianchini, Valeria; Angelone, Anna Maria; Aloisio, Federica; Cofini, Vincenza; Zazzara, Francesca; Di Orio, Ferdinando

    2016-01-01

    Natural disasters, such as the earthquake that occurred in the province of L'Aquila in central Italy, in 2009, generally increase the demand for healthcare. A survey was conducted to assess perception of health status an d use of health services in a sample of L'Aquila's resident population, five years after the event, and in a comparison population consisting of a sample of the resident population of Avezzano, a town in the same region, not affected by the earthquake. No differences were found in perception of health status between the two populations. Both groups reported difficulties in accessing specialized healthcare and rehabilitation services. PMID:27077558

  20. Phenetic relationships among natural population accessions of Glycyrrhiza glabra L. (Fabaceae in central Zagros region of Iran, based on quantitative morphology, flavonoids and glycyrrhizin contents data

    Directory of Open Access Journals (Sweden)

    Majid Sharifi-Tehrani

    2013-01-01

    Full Text Available Phenetic relationships among thirty five accessions from natural populations of two varieties of Glycyrrhiza glabra in central Zagros region of Iran were studied. Twenty one quantitative morphological characters were measured for twenty seven accessions. PCO, clustering, K-means and MDS analyses were performed on morphological dataset. Polar flavonoid constituents of twenty four accessions were extracted, purified using TLC and characterized at the skeleton class level. Glycyrrhizin contents of rhizomes in twenty four accessions were quantified using image processing methods. Results of multivariate analysis of both morphological and flavonoid spot profile data showed that accessions could be partitioned into two main groups based on geographical locality of the populations. The most variable morphological trait based on CV values, was seed area and the least variable one was Legume width in the widest portion. Accessions of both varieties produced various flavonoids of class flavones and flavonols. Seven flavonoid constituents from the two varieties were separated based on different Rf values. The results revealed that there were moderate (not prominent levels of variation between the studied accessions. Separation of the varieties based on the single qualitative character in the available literature, was confirmed. Rhizomes of both varieties showed similar amounts of glycyrrhizin and almost similar types of flavonoids in their TLC profiles, suggesting that both were equivalent as herbal drugs in folk medicine.

  1. Diversity and evolution of the microbial populations during manufacture and ripening of Casín, a traditional Spanish, starter-free cheese made from cow's milk.

    Science.gov (United States)

    Alegría, Angel; Alvarez-Martín, Pablo; Sacristán, Noelia; Fernández, Elena; Delgado, Susana; Mayo, Baltasar

    2009-11-30

    Classical culturing and denaturing gradient gel electrophoresis (DGGE) techniques have been used for studying the microbial diversity and dynamics of the traditional Spanish Casín cheese during manufacturing and ripening. As with other starter-free cheeses made from raw milk, the microbial diversity of Casín was shown to be high by both culturing and DGGE analyses. The culture technique showed that lactic acid bacteria (LAB) species constituted the majority of the microbial populations. Of the 14 bacterial species identified, Lactococcus garvieae was predominant in the three-day-old cheese sample, although it was replaced by Lactococcus lactis subsp. lactis at day 30. As expected, the DGGE profiles obtained were complex, consisting, depending on the sample, in five to ten different amplification bands. Among these, a band corresponding to Streptococcus thermophilus was observed throughout the whole manufacturing process. This species had never been identified from traditional Spanish cheeses previously. Culturing and molecular methods showed high populations of undesirable microorganisms, arguing for a required improvement in the hygiene of Casín manufacture. Random amplification of polymorphic DNA (RAPD) profiling suggested that the L. garvieae and L. lactis populations were composed of one and five strains, respectively. In addition, only a single L. lactis RAPD pattern was stably maintained from day three to day 30, indicating high succession of strains along ripening. After a thoroughly characterisation, strains of the two Lactococcus species could be used in designing specific starter cultures for Casín. Additional species (such as Lactobacillus plantarum and Corynebacterium variabile) might be included as adjunct cultures.

  2. A nutrition strategy to reduce the burden of diet related disease: access to dietician services must complement population health approaches.

    Science.gov (United States)

    Segal, Leonie; Opie, Rachelle S

    2015-01-01

    Poor diet quality is implicated in almost every disease and health issue. And yet, in most advanced market economies diet quality is poor, with a minority meeting guidelines for healthy eating. Poor diet is thus responsible for substantial disease burden. Societies have at their disposal a range of strategies to influence diet behaviors. These can be classified into: (i) population level socio-educational approaches to enhance diet knowledge; (ii) pricing incentives (subsidies on healthy foods, punitive taxes on unhealthy foods); (iii) regulations to modify the food environment, and (iv) the provision of clinical dietetic services. There is little evidence that societies are active in implementing the available strategies. Advertising of "junk foods" is largely unchecked, contrasting with strict controls on advertising tobacco products, which also attract punitive taxes. Access to dieticians is restricted in most countries, even in the context of universal health care. In Australia in 2011 there were just 2,969 practicing dieticians/nutritionists or 1.3 clinicians per 10,000 persons, compared with 5.8 physiotherapists per 10,000 persons, 14.8 general practitioners (family physicians) per 10,000 persons or 75 nurses per 10,000 persons. It is time to implement comprehensive national nutrition strategies capable of effecting change. Such strategies need to be multi-component, incorporating both public health approaches and expanded publicly funded dietetic services. Access to individualized dietetic services is needed by those at risk, or with current chronic conditions, given the complexity of the diet message, the need for professional support for behavior change and to reflect individual circumstances. The adoption of a comprehensive nutrition strategy offers the promise of substantial improvement in diet quality, better health and wellbeing and lower health care costs. PMID:26321951

  3. Deep Diversity: Novel Approach to Overcoming the PCR Bias Encountered During Environmental Analysis of Microbial Populations for Alpha-Diversity

    Science.gov (United States)

    Ramirez, Gustavo A; Vaishampayan, Parag A.

    2011-01-01

    Alpha-diversity studies are of crucial importance to environmental microbiologists. The polymerase chain reaction (PCR) method has been paramount for studies interrogating microbial environmental samples for taxon richness. Phylogenetic studies using this technique are based on the amplification and comparison of the 16S rRNA coding regions. PCR, due disproportionate distribution of microbial species in the environment, increasingly favors the amplification of the most predominant phylotypes with every subsequent reaction cycle. The genetic and chemical complexity of environmental samples are intrinsic factors that exacerbate an inherit bias in PCR-based quantitative and qualitative studies of microbial communities. We report that treatment of a genetically complex total genomic environmental DNA extract with Propidium Monoazide (PMA), a DNA intercalating molecule capable of forming a covalent cross-linkage to organic moieties upon light exposure, disproportionally inactivates predominant phylotypes and results in the exponential amplification of previously shadowed microbial ?-diversity quantified as a 19.5% increase in OUTs reported via phylogenetic screening using PhyloChip.

  4. An Evaluation of Behavioral Health Compliance and Microbial Risk Factors on Student Populations within a High-Density Campus

    Science.gov (United States)

    Decker, Jody F.; Slawson, Robin M.

    2012-01-01

    Objective: The aim of this Canadian study was to assess student behavioral response to disease transmission risk, while identifying high microbial deposition/transmission sites. Participants: A student survey was conducted during October 2009. Methods: The methods included a survey of students to assess use of health services, vaccination…

  5. Soil Microbial Population in the Vicinity of the Bean Caper(Zygophyllum dumosum) Root Zone in a Desert System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The aim of the current study was to gain a better understanding of the changes in soil microbial biomass and basal respiration dynamics in the vicinity of the bean caper (Zygophyllum dumosum) perennial desert shrub and the inter-shrub sites. Microbial biomasses as well as basal respiration were found to be significantly greater in the soil samples taken beneath the Z. dumosum shrubs than from the inter-shrub sampling sites, with no differences between the two sampling layers (0-10 and 10-20 cm) throughout the study period. However, seasonal changes were observed due to autumn dew formation, which significantly affected microbial biomass and basal respiration in the upper-layer inter-shrub locations.The calculated metabolic coefficient (qCO2) revealed significant differences between the two sampling sites as well as between the two soil layers, elucidating the abiotic effect between the sites throughout the study period. The substrate availability index was found to significantly demonstrate the differences between the two sites, elucidating the significant contribution of Z. dumosum in food source availability and in moderating harsh abiotic components. The importance of basal microbial parameters and the derived indices as tools demonstrated the importance and need for basic knowledge in understanding plant-soil interactions determined by an unpredictable and harsh desert environment.

  6. 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.

  7. Impact of rhizobial populations and their host legumes on microbial activity in soils of arid regions in Tunisia

    International Nuclear Information System (INIS)

    Nitrogen fixing legumes and their microsymbionts are a fundamental contributor to soil fertility and prevent their degradation in arid and semi arid ecosystems. In Tunisia, few data are available on the contribution of these legumes in microbial activity in the arid soil. In this objective, a study was undertaken on five leguminous species from different arid regions to evaluate their ability to regenerate microbiological processes of the soil: Genista saharea, Genista microcephala, Acacia tortilis sspr raddiana, Retama raetam and Prosopis stephaniana. (Author)

  8. Impact of rhizobial populations and their host legumes on microbial activity in soils of arid regions in Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Fterich, A.; Mahdhi, M.; Mars, M.

    2009-07-01

    Nitrogen fixing legumes and their microsymbionts are a fundamental contributor to soil fertility and prevent their degradation in arid and semi arid ecosystems. In Tunisia, few data are available on the contribution of these legumes in microbial activity in the arid soil. In this objective, a study was undertaken on five leguminous species from different arid regions to evaluate their ability to regenerate microbiological processes of the soil: Genista saharea, Genista microcephala, Acacia tortilis sspr raddiana, Retama raetam and Prosopis stephaniana. (Author)

  9. Responses in digestion, rumen fermentation and microbial populations to inhibition of methane formation by a halogenated methane analogue.

    Science.gov (United States)

    Mitsumori, Makoto; Shinkai, Takumi; Takenaka, Akio; Enishi, Osamu; Higuchi, Koji; Kobayashi, Yosuke; Nonaka, Itoko; Asanuma, Narito; Denman, Stuart E; McSweeney, Christopher S

    2012-08-01

    The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50 % Timothy grass and 50 % concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91 %, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.

  10. 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.

  11. Optimising locational access of deprived populations to farmers' markets at a national scale: one route to improved fruit and vegetable consumption?

    Science.gov (United States)

    Pearson, Amber L; Wilson, Nick

    2013-01-01

    Background. Evidence suggests that improved locational access to farmers' markets increases fruit and vegetable (FV) consumption, particularly for low-income groups. Therefore, we modelled potential alternative distributions of farmers' markets in one country (New Zealand) to explore the potential impact for deprived populations and an indigenous population (Māori). Methods. Data were collected on current farmers' markets (n = 48), population distributions, area deprivation, and roads. Geographic analyses were performed to optimize market locations for the most deprived populations. Results. We found that, currently, farmers' markets provided fairly poor access for the total population: 7% within 12.5 km (15 min driving time); 5% within 5 km; and 3% within 2 km. Modelling the optimal distribution of the 48 markets substantially improved access for the most deprived groups: 9% (vs 2% currently) within 12.5 km; 5% (vs 1%) within 5 km; and 3% (vs 1%) within 2 km. Access for Māori also improved: 22% (vs 7%) within 12.5 km; 12% (vs 4%) within 5 km; and 6% (vs 2%) within 2 km. Smaller pro-equity results arose from optimising the locations of the 18 least pro-equity markets or adding 10 new markets. Conclusion. These results highlight the potential for improving farmers' market locations to increase accessibility for groups with low FV consumption. Given that such markets are easily established and relocated, local governments could consider these results to inform decisions, including subsidies for using government land and facilities. Such results can also inform central governments planning around voucher schemes for such markets and exempting them from taxes (e.g., VAT/GST). PMID:23862107

  12. Optimising locational access of deprived populations to farmers’ markets at a national scale: one route to improved fruit and vegetable consumption?

    Directory of Open Access Journals (Sweden)

    Amber L. Pearson

    2013-07-01

    Full Text Available Background. Evidence suggests that improved locational access to farmers’ markets increases fruit and vegetable (FV consumption, particularly for low-income groups. Therefore, we modelled potential alternative distributions of farmers’ markets in one country (New Zealand to explore the potential impact for deprived populations and an indigenous population (Māori. Methods. Data were collected on current farmers’ markets (n = 48, population distributions, area deprivation, and roads. Geographic analyses were performed to optimize market locations for the most deprived populations. Results. We found that, currently, farmers’ markets provided fairly poor access for the total population: 7% within 12.5 km (15 min driving time; 5% within 5 km; and 3% within 2 km. Modelling the optimal distribution of the 48 markets substantially improved access for the most deprived groups: 9% (vs 2% currently within 12.5 km; 5% (vs 1% within 5 km; and 3% (vs 1% within 2 km. Access for Māori also improved: 22% (vs 7% within 12.5 km; 12% (vs 4% within 5 km; and 6% (vs 2% within 2 km. Smaller pro-equity results arose from optimising the locations of the 18 least pro-equity markets or adding 10 new markets. Conclusion. These results highlight the potential for improving farmers’ market locations to increase accessibility for groups with low FV consumption. Given that such markets are easily established and relocated, local governments could consider these results to inform decisions, including subsidies for using government land and facilities. Such results can also inform central governments planning around voucher schemes for such markets and exempting them from taxes (e.g., VAT/GST.

  13. Community Characterization of Microbial Populations Found at a Cold Water Sulfidic Spring in the Canadian High Arctic

    Science.gov (United States)

    Trivedi, C.; Lau, G. E.; Templeton, A. S.; Grasby, S. E.; Spear, J. R.

    2015-12-01

    The unique environment on Europa makes it an ideal target for astrobiological investigation. One such earth-based analogue to aid in this investigation is the sulfur-dominated glacial spring system found at Borup Fiord Pass (BFP), Ellesmere Island, Nunavut, Canada. In this system, subsurface microbial sulfate reduction produces hydrogen sulfide, which is transported through the glacier along spring channels [1]. As the surface oxidation of H2S occurs, resultant deposition of elemental sulfur (S0) and other minerals becomes visible (attached image). The energy released from these reactions can support potential microbial metabolisms and may be a valuable representation of microbial processes occurring on Europa. The resulting sulfur minerals provide sensitive records of dynamic atmospheric, geological, hydrological, chemical, and biological processes on planetary surfaces. Moreover, we expect that the S0-rich deposits of this glacial spring system will serve as a mineralogical record for biological activity and will provide a valuable tool for recognizing potential sulfur-based life on Europa. During a recent collaborative expedition (2014) to BFP, samples were taken from the toe of the glacier in an area called the 'Blister Crust' (attached image). At this location, glacial channels reach the surface, representing an active interface between subsurface and surface processes. Initial geochemical characterization at the site revealed high amounts of aqueous sulfide (1.8 mM) and hydrogen (29 nM), which likely serve as the electron donation potential in the system. Furthermore, preliminary 16S rRNA gene sequencing has shown a high abundance of the genus Sulfurimonas, which is a known sulfur metabolizer. Our research seeks to further characterize microbial communities found at this interface in order to elucidate information regarding in situ sulfur cycling and the potential to tie this into subsurface/surface processes on Europa. Continued work will provide guidance

  14. Populism

    OpenAIRE

    Abts, Koenraad; van Kessel, Stijn

    2015-01-01

    Populism is a concept applied to a wide range of political movements and actors across the globe. There is, at the same time, considerable confusion about the attributes and manifestation of populism, as well as its impact on democracy. This contribution identifies the defining elements of the populist ideology and discusses the varieties in which populism manifests itself, for instance as a component of certain party families. We finally discuss various normative interpretations of populism,...

  15. Temperature and solids retention time control microbial population dynamics and volatile fatty acid production in replicated anaerobic digesters

    Science.gov (United States)

    Vanwonterghem, Inka; Jensen, Paul D.; Rabaey, Korneel; Tyson, Gene W.

    2015-02-01

    Anaerobic digestion is a widely used technology for waste stabilization and generation of biogas, and has recently emerged as a potentially important process for the production of high value volatile fatty acids (VFAs) and alcohols. Here, three reactors were seeded with inoculum from a stably performing methanogenic digester, and selective operating conditions (37°C and 55°C 12 day and 4 day solids retention time) were applied to restrict methanogenesis while maintaining hydrolysis and fermentation. Replicated experiments performed at each set of operating conditions led to reproducible VFA production profiles which could be correlated with specific changes in microbial community composition. The mesophilic reactor at short solids retention time showed accumulation of propionate and acetate (42 +/- 2% and 15 +/- 6% of CODhydrolyzed, respectively), and dominance of Fibrobacter and Bacteroidales. Acetate accumulation (>50% of CODhydrolyzed) was also observed in the thermophilic reactors, which were dominated by Clostridium. Under all tested conditions, there was a shift from acetoclastic to hydrogenotrophic methanogenesis, and a reduction in methane production by >50% of CODhydrolyzed. Our results demonstrate that shortening the SRT and increasing the temperature are effective strategies for driving microbial communities towards controlled production of high levels of specific volatile fatty acids.

  16. Microbial populations identified by fluorescence in situ hybridization in a constructed wetland treating acid coal mine drainage.

    Science.gov (United States)

    Nicomrat, Duongruitai; Dick, Warren A; Tuovinen, Olli H

    2006-01-01

    Microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (AMD) are only poorly understood. The purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving AMD using fluorescence in situ hybridization (FISH) analysis. Seasonal samples of oxic surface sediments, comprised of Fe(III) precipitates, were collected from two treatment cells of the constructed wetland system. The pH of the bulk samples ranged between pH 2.1 and 3.9. Viable counts of acidophilic Fe and S oxidizers and heterotrophs were determined with a most probable number (MPN) method. The MPN counts were only a fraction of the corresponding FISH counts. The sediment samples contained microorganisms in the Bacteria (including the subgroups of acidophilic Fe- and S-oxidizing bacteria and Acidiphilium spp.) and Eukarya domains. Archaea were present in the sediment surface samples at detection in the bacterial community. The results from the FISH technique from this field study are consistent with results from other experiments involving enumeration by most probable number, dot-blot hybridization, and denaturing gradient gel electrophoresis analyses and with the geochemistry of the site. PMID:16825452

  17. Difficulties in accessing and availing of public health care systems among rural population in Chittoor District, Andhra Pradesh

    Directory of Open Access Journals (Sweden)

    Geetha Lakshmi Sreerama

    2015-01-01

    Full Text Available Context: Despite policies to make health care accessible to all, it is not universally accessible. Frequent evaluation of barriers to accessibility of health care services paves path for improvement. Hence, present study is undertaken to evaluate the factors and public health policies influencing health care access to rural people in Chittoor District, Andhra Pradesh, which can be interpolated for other regions. Aims: To assess knowledge, perceptions, availing of public health care services, barriers to health care access in Chittoor District, Andhra Pradesh. Settings and Design: Cross-sectional, hospital-based survey in the Government Maternity Hospital (GMH, Tirupati, a tertiary care center. Materials and Methods: Fifty women delivered normally in GMH through convenient sampling technique. Data collected on standardized pro forma as per IMS Institute of Healthcare Informatics. Statistical Analysis Used: Is done through MS Excel 2007, Epi Info 7 (of Centres for Disease Control and Prevention, Atlanta, USA and frequencies were described. Results: Distance, waiting hours, societal responsibility, nature of the illness, presumed commercialization of Medicare system, attitudes of health care providers, and loss of wages were not barriers for accessing health care. Accredited Social Health Activist (ASHA and availability of ambulance services made great improvements in health care accessibility. Absenteeism of health care providers is a problem. Conclusions: Expanding the ambulance services and ASHA network will be an effective measure for further accessibility to health care. Absenteeism of health care providers needs correction.

  18. Effect of Scrophularia striata and Ferulago angulata, as alternatives to virginiamycin, on growth performance, intestinal microbial population, immune response, and blood constituents of broiler chickens.

    Science.gov (United States)

    Rostami, Farhad; Ghasemi, Hossein A; Taherpour, Kamran

    2015-09-01

    An experiment was conducted to investigate the comparative effect of Scrophularia striata, Ferulago angulata, and virginiamycin (VM) on performance, intestinal microbial population, immune response, and blood constituents of broilers. A total of 300 Ross 308 male broiler chickens were randomly assigned to 5 treatments, with 5 replicates/treatment (10 chickens/pen). Birds were fed either a corn-soybean meal basal diet (control) or the basal diet supplemented with 200 mg/kg VM; 4 g/kg S. striata (SS1); 8 g/kg S. striata (SS2); 4 g/kg F. angulata (FA1); or 8 g/kg F. angulata (FA2). After 6 wk, the BW, ADG, and feed-to-gain ratio (F:G) of the VM, SS1, and FA1 groups were better (Pantibiotic growth promoter. Furthermore, a high dose of both herbs (8 g/kg diet) could beneficially affect the intestinal health and immune status of broilers. PMID:26217029

  19. Populations of selected microbial and fungal species growing on the surface of rape seeds following treatment with desiccants or plant growth regulators.

    Science.gov (United States)

    Frac, Magdalena; Jezierska-Tys, Stefania; Tys, Jerzy

    2010-01-01

    The aim of this study was to determine the effects of desiccants and plant growth regulators on selected microbial species affecting rape seeds, with special emphasis on the growth of fungi and identification of the genus and species composition. The experimental material in the study was seeds of winter rape cv. Californium that were collected from the field during combine harvest. The chemical agents applied, both desiccants and growth regulators, generally decreased the populations of bacteria occurring on the surface of rape seeds. The responses of fungi depended upon the type of agent applied and were manifested as either stimulation or inhibition of the growth of the fungal species. The fungi isolated from the surface of rape seeds were characteristic of those found in the field environment (Cladosporium and Penicillium) and typical for those present on the surface of rape seeds (Alternaria).

  20. Population dynamics of transgenic strain Escherichia coli Z905/pPHL7 in freshwater and saline lake water microcosms with differing microbial community structures

    Science.gov (United States)

    Popova, L. Yu; Kargatova, T. V.; Ganusova, E. E.; Lobova, T. I.; Boyandin, A. N.; Mogilnaya, O. A.; Pechurkin, N. S.

    2005-01-01

    Populations of Escherichia coli Z905/pPHL7, a transgenic microorganism, were heterogenic in the expression of plasmid genes when adapting to the conditions of water microcosms of various mineralization levels and structure of microbial community. This TM has formed two subpopulations (ampicillin-resistant and ampicillin-sensitive) in every microcosm. Irrespective of mineralization level of a microcosm, when E. coli Z905/pPHL7 alone was introduced, the ampicillin-resistant subpopulation prevailed, while introduction of the TM together with indigenous bacteria led to the dominance of the ampicillin-sensitive subpopulation. A high level of lux gene expression maintained longer in the freshwater microcosms than in sterile saline lake water microcosms. A horizontal gene transfer has been revealed between the jointly introduced TM and Micrococcus sp. 9/pSH1 in microcosms with the Lake Shira sterile water. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

  1. Ocean microbial metagenomics

    Science.gov (United States)

    Kerkhof, Lee J.; Goodman, Robert M.

    2009-09-01

    Technology for accessing the genomic DNA of microorganisms, directly from environmental samples without prior cultivation, has opened new vistas to understanding microbial diversity and functions. Especially as applied to soils and the oceans, environments on Earth where microbial diversity is vast, metagenomics and its emergent approaches have the power to transform rapidly our understanding of environmental microbiology. Here we explore select recent applications of the metagenomic suite to ocean microbiology.

  2. The Influence of Mineral Fertilizer Combined With a Nitrification Inhibitor on Microbial Populations and Activities in Calcareous Uzbekistanian Soil Under Cotton Cultivation

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdiyeva

    2001-01-01

    Full Text Available Application of fertilizers combined with nitrification inhibitors affects soil microbial biomass and activity. The objective of this research was to determine the effects of fertilizer application combined with the nitrification inhibitor potassium oxalate (PO on soil microbial population and activities in nitrogen-poor soil under cotton cultivation in Uzbekistan. Fertilizer treatments were N as urea, P as ammophos, and K as potassium chloride. The nitrification inhibitor PO was added to urea and ammophos at the rate of 2%. Three treatments—N200P140K60 (T1, N200 P140 POK60 (T2, and N200 P140 POK60 (T3 mg kg-1 soil—were applied for this study. The control (C was without fertilizer and PO. The populations of oligotrophic bacteria, ammonifying bacteria, nitrifying bacteria, denitrifying bacteria, mineral assimilating bacteria, oligonitrophilic bacteria, and bacteria group Azotobacter were determined by the most probable number method. The treatments T2 and T3 increased the number of oligonitrophilic bacteria and utilization mineral forms of nitrogen on the background of reducing number of ammonifying bacteria. T2 and T3 also decreased the number of nitrifying bacteria, denitrifying bacteria, and net nitrification. In conclusion, our experiments showed that PO combined with mineral fertilizer is one of the most promising compounds for inhibiting nitrification rate, which was reflected in the increased availability and efficiency of fertilizer nitrogen to the cotton plants. PO combined with mineral fertilizer has no negative effects on nitrogen-fixing bacteria Azotobacter and oligo-nitrophilic bacteria.

  3. 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.

  4. 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. PMID:26992104

  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. Effects of Secondary Plant Metabolites on Microbial Populations: Changes in Community Structure and Metabolic Activity in Contaminated Environments

    Science.gov (United States)

    Musilova, Lucie; Ridl, Jakub; Polivkova, Marketa; Macek, Tomas; Uhlik, Ondrej

    2016-01-01

    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. PMID:27483244

  7. Effects of Secondary Plant Metabolites on Microbial Populations: Changes in Community Structure and Metabolic Activity in Contaminated Environments.

    Science.gov (United States)

    Musilova, Lucie; Ridl, Jakub; Polivkova, Marketa; Macek, Tomas; Uhlik, Ondrej

    2016-01-01

    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. PMID:27483244

  8. Effect of conventional chemical treatment on the microbial population in a biofouling layer of reverse osmosis systems.

    Science.gov (United States)

    Bereschenko, L A; Prummel, H; Euverink, G J W; Stams, A J M; van Loosdrecht, M C M

    2011-01-01

    The impact of conventional chemical treatment on initiation and spatiotemporal development of biofilms on reverse osmosis (RO) membranes was investigated in situ using flow cells placed in parallel with the RO system of a full-scale water treatment plant. The flow cells got the same feed (extensively pre-treated fresh surface water) and operational conditions (temperature, pressure and membrane flux) as the full-scale installation. With regular intervals both the full-scale RO membrane modules and the flow cells were cleaned using conventional chemical treatment. For comparison some flow cells were not cleaned. Sampling was done at different time periods of flow cell operation (i.e., 1, 5, 10 and 17 days and 1, 3, 6 and 12 months). The combination of molecular (FISH, DGGE, clone libraries and sequencing) and microscopic (field emission scanning electron, epifluorescence and confocal laser scanning microscopy) techniques made it possible to thoroughly analyze the abundance, composition and 3D architecture of the emerged microbial layers. The results suggest that chemical treatment facilitates initiation and subsequent maturation of biofilm structures on the RO membrane and feed-side spacer surfaces. Biofouling control might be possible only if the cleaning procedures are adapted to effectively remove the (dead) biomass from the RO modules after chemical treatment.

  9. Predominant Acidilobus-like populations from geothermal environments in yellowstone national park exhibit similar metabolic potential in different hypoxic microbial communities.

    Science.gov (United States)

    Jay, Z J; Rusch, D B; Tringe, S G; Bailey, C; Jennings, R M; Inskeep, W P

    2014-01-01

    High-temperature (>70°C) ecosystems in Yellowstone National Park (YNP) provide an unparalleled opportunity to study chemotrophic archaea and their role in microbial community structure and function under highly constrained geochemical conditions. Acidilobus spp. (order Desulfurococcales) comprise one of the dominant phylotypes in hypoxic geothermal sulfur sediment and Fe(III)-oxide environments along with members of the Thermoproteales and Sulfolobales. Consequently, the primary goals of the current study were to analyze and compare replicate de novo sequence assemblies of Acidilobus-like populations from four different mildly acidic (pH 3.3 to 6.1) high-temperature (72°C to 82°C) environments and to identify metabolic pathways and/or protein-encoding genes that provide a detailed foundation of the potential functional role of these populations in situ. De novo assemblies of the highly similar Acidilobus-like populations (>99% 16S rRNA gene identity) represent near-complete consensus genomes based on an inventory of single-copy genes, deduced metabolic potential, and assembly statistics generated across sites. Functional analysis of coding sequences and confirmation of gene transcription by Acidilobus-like populations provide evidence that they are primarily chemoorganoheterotrophs, generating acetyl coenzyme A (acetyl-CoA) via the degradation of carbohydrates, lipids, and proteins, and auxotrophic with respect to several external vitamins, cofactors, and metabolites. No obvious pathways or protein-encoding genes responsible for the dissimilatory reduction of sulfur were identified. The presence of a formate dehydrogenase (Fdh) and other protein-encoding genes involved in mixed-acid fermentation supports the hypothesis that Acidilobus spp. function as degraders of complex organic constituents in high-temperature, mildly acidic, hypoxic geothermal systems.

  10. 污水处理活性污泥微生物群落多样性研究%Microbial Population Diversity of Activated Sludge for Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    金浩; 李柏林; 欧杰; 陈兰明

    2012-01-01

    为研究污水处理活性污泥微生物多样性,提取了活性污泥宏基因组DNA,并采用细菌通用引物27F和1492R扩增了上海污泥厂活性污泥细菌16S rDNA片段,构建了细菌16S rDNA克隆文库,并对该文库中的微生物群落进行了分析.共获得200条高质量序列并建立系统发育树,结果显示活性污泥主要的细菌类群为变形菌门(Proteobacteria)(91.9%)、厚壁菌门(Firmicures)(4.6%)、拟杆菌门(Bacteroidetes)(2%)、绿弯菌门(Chloroflexi)(0.5%)、硝化螺菌门(Nitrospirae)(1%).其中,明显的优势菌群为Alcaligenes feacalis(55%)、Pseudomonas aeruginosa(12.8%)和Stenotrophomonas(12.8%),优势菌的产酶能力在活性污泥中显示生态修复功能菌的作用.%In order to study the microbial diversity of activated sludge (AS) for wastewater treatment, the macro-ge-nomic DNA of the AS was extracted from a wastewater factory in Shanghai. The 16S rDNA of the AS bacteria was amplified using bacteria general primers 27F and 1492R to construct the bacterial 16S rDNA clone library, and analyzed the microbial population of the library. All together 200 bands of high quality sequences were obtained and established a phylogenetic tree. The results showed that the main bacterial population of the AS was the phyla of Proteobacteria (91.9% ) , Firmicutes (4.6% ) , Bacteroidetes (2% ) , Chloroflexi (0.5% ) , Nitrospirae (1% ). Among them Al-caligenes feacalis (55% ) , Pseudomonas aeruginosa ( 12. 8% ) , and Stenolrophomonas ( 12. 8% ) were noticeably dominant bacterial population, enzyme production capacity of the dominant bacteria showed the ecological restoration function in the AS.

  11. 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 (pgroups 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 (pgroup. The total cholesterol was lower (pgroups than that in the basal treatment group. The intestinal Lactobacillus population was greater (pgroups 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.

  12. Microbial population in cloud water at the Puy de Dôme: Implications for the chemistry of clouds

    Science.gov (United States)

    Amato, Pierre; Ménager, Matthieu; Sancelme, Martine; Laj, Paolo; Mailhot, Gilles; Delort, Anne-Marie

    Airborne micro-organisms are ubiquitous in the atmosphere where they can remain alive and be transported over long distances, thus colonizing new environments. Despite their great importance in relation to ecological and socio-economical issues (bio-terrorism, health, etc.) very few studies have been carried out in this field. In this study, the structure of the microbial community present in atmospheric water samples from clouds at the Puy de Dôme (alt 1465 m, Massif Central, France) is described and the metabolic potential of some bacteria is investigated. The total microflora has been quantified by epifluorescence microscopy, while the cultivable aerobic micro-organisms were isolated. Bacteria were identified by 16S DNA sequencing and fungi by morphological criteria. The total bacterial count reached about 3×10 4 cells m -3 of cloud volume (1×10 5 cells mL -1 of cloud water), of which less than 1% are cultivable. Most of the isolated micro-organisms, including 12 fungal and 17 bacterial strains, are described here for the first time in atmospheric water. Many bacterial strains seem to be adapted to the extreme conditions found in cloud water (pH, T°, UV radiations, etc.). Comparison of the two samples (March 2003) shows that pH can be a major factor controlling the structure of this community: an acidic pH (Sample 1: pH=4, 9) favours the presence of fungi and spore-forming bacteria, while a more neutral pH (Sample 2: pH=5, 8) favours greater biodiversity. We have also shown, using in situ 1H NMR, that most of the isolated bacteria are able to degrade various organic substrates such as formate, acetate, lactate, methanol and formaldehyde which represent the major organic compounds present in cloud water. In addition, the detection of intermediates indicated preferential metabolic routes for some of the strains.

  13. Evaluation of microbial population and functional genes during the bioremediation of petroleum-contaminated soil as an effective monitoring approach.

    Science.gov (United States)

    Shahi, Aiyoub; Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-03-01

    This study investigated the abundance and diversity of soil n-alkane and polycyclic aromatic hydrocarbon (PAH)-degrading bacterial communities. It also investigated the quantity of the functional genes, the occurrence of horizontal gene transfer (HGT) in the identified bacterial communities and the effect that such HGT can have on biostimulation process. Illumina sequencing was used to detect the microbial diversity of petroleum-polluted soil prior to the biostimulation process, and quantitative real-time PCR was used to determine changes in the bacterial community and functional genes (alkB, phnAc and nah) expressions throughout the biostimulation of petroleum-contaminated soil. The illumine results revealed that γ-proteobacteria, Chloroflexi, Firmicutes, and δ-proteobacteria were the most dominant bacterial phyla in the contaminated site, and that most of the strains were Gram-negative. The results of the gene expression results revealed that gram-negative bacteria and alkB are critical to successful bioremediation. Failure to maintain the stability of hydrocarbon-degrading bacteria and functional gene will reduce the extend to which alkanes and PAHs are degraded. According to the results of the study, the application of a C:N:P ratio of was 100:15:1 in the biodegradation experiment resulted in the highest rate at which petroleum hydrocarbons were biodegraded. The diversity of pollutant-degrading bacteria and the effective transfer of degrading genes among resident microorganisms are essential factors for the successful biostimulation of petroleum hydrocarbons. As such, screening these factors throughout the biostimulation process represents an effective monitoring approach by which the success of the biostimulation can be assessed. PMID:26685788

  14. Evaluation of microbial population and functional genes during the bioremediation of petroleum-contaminated soil as an effective monitoring approach.

    Science.gov (United States)

    Shahi, Aiyoub; Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-03-01

    This study investigated the abundance and diversity of soil n-alkane and polycyclic aromatic hydrocarbon (PAH)-degrading bacterial communities. It also investigated the quantity of the functional genes, the occurrence of horizontal gene transfer (HGT) in the identified bacterial communities and the effect that such HGT can have on biostimulation process. Illumina sequencing was used to detect the microbial diversity of petroleum-polluted soil prior to the biostimulation process, and quantitative real-time PCR was used to determine changes in the bacterial community and functional genes (alkB, phnAc and nah) expressions throughout the biostimulation of petroleum-contaminated soil. The illumine results revealed that γ-proteobacteria, Chloroflexi, Firmicutes, and δ-proteobacteria were the most dominant bacterial phyla in the contaminated site, and that most of the strains were Gram-negative. The results of the gene expression results revealed that gram-negative bacteria and alkB are critical to successful bioremediation. Failure to maintain the stability of hydrocarbon-degrading bacteria and functional gene will reduce the extend to which alkanes and PAHs are degraded. According to the results of the study, the application of a C:N:P ratio of was 100:15:1 in the biodegradation experiment resulted in the highest rate at which petroleum hydrocarbons were biodegraded. The diversity of pollutant-degrading bacteria and the effective transfer of degrading genes among resident microorganisms are essential factors for the successful biostimulation of petroleum hydrocarbons. As such, screening these factors throughout the biostimulation process represents an effective monitoring approach by which the success of the biostimulation can be assessed.

  15. Microbial diversity in the midguts of field and lab-reared populations of the European corn borer Ostrinia nubilalis.

    Directory of Open Access Journals (Sweden)

    Eugeni Belda

    Full Text Available BACKGROUND: Insects are associated with microorganisms that contribute to the digestion and processing of nutrients. The European Corn Borer (ECB is a moth present world-wide, causing severe economical damage as a pest on corn and other crops. In the present work, we give a detailed view of the complexity of the microorganisms forming the ECB midgut microbiota with the objective of comparing the biodiversity of the midgut-associated microbiota and explore their potential as a source of genes and enzymes with biotechnological applications. METHODOLOGICAL/PRINCIPAL FINDINGS: A high-throughput sequencing approach has been used to identify bacterial species, genes and metabolic pathways, particularly those involved in plant-matter degradation, in two different ECB populations (field-collected vs. lab-reared population with artificial diet. Analysis of the resulting sequences revealed the massive presence of Staphylococcus warneri and Weissella paramesenteroides in the lab-reared sample. This enabled us to reconstruct both genomes almost completely. Despite the apparently low diversity, 208 different genera were detected in the sample, although most of them at very low frequency. By contrast, the natural population exhibited an even higher taxonomic diversity along with a wider array of cellulolytic enzyme families. However, in spite of the differences in relative abundance of major taxonomic groups, not only did both metagenomes share a similar functional profile but also a similar distribution of non-redundant genes in different functional categories. CONCLUSIONS/SIGNIFICANCE: Our results reveal a highly diverse pool of bacterial species in both O. nubilalis populations, with major differences: The lab-reared sample is rich in gram-positive species (two of which have almost fully sequenced genomes while the field sample harbors mainly gram-negative species and has a larger set of cellulolytic enzymes. We have found a clear relationship between the

  16. Present status of the endangered limpet Cymbula nigra (Gastropoda, Patellidae in Ceuta: how do substrate heterogeneity and area accessibility affect population structure?

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    Rivera–Ingraham, G. A.

    2011-12-01

    Full Text Available Cymbula nigra (Gastropoda, Patellidae is a threatened giant patellid limpet found on the North African coast from Namibia to Algeria. The objective of this study was to estimate the total number of individuals present in Ceuta (Strait of Gibraltar and to determine the effect of certain physical parameters on population structure and abundance. Between 2006 and 2010 we conducted an exhaustive census in the area. Results indicate that Ceuta could be home to 48,473 individuals. The most important populations were recorded on the North Bay, characterized by its Atlantic influence. While for other similar species, such as Patella ferruginea, human accessibility to the area plays an important role in determining the structure of populations, we found that substrate roughness (small scale topographic heterogeneity is the main determining factor in this species. Populations located on medium to low topographic heterogeneity substrates showed higher percentages of medium and large size individuals. However, recruitment rates did not differ between substrata of different roughness. Finally, and through the analysis of the C. nigra populations located on some recently constructed jetties, we obtained interesting new data regarding individual growth rates, thus contributing to our knowledge of the population structure of the species.

  17. Distinct microbial populations are tightly linked to the profile of dissolved iron in the methanic sediments of the Helgoland mud area, North Sea

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    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.

  18. 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

    OpenAIRE

    Kristensen, Matilde Bylov; Metzdorff, Stine Broeng; Bergström, Anders; Damlund, Dina S M; Fink, Lisbeth N; Licht, Tine Rask; Frøkiær, Hanne

    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 colonized (CONV) mice than in mono-colonized (MC) and germfree (GF) mice, and the CD4(+) T cell population established faster in CONV mice. At the day of birth, compared to GF mice, the expression...

  19. On the discrepancy of access to higher education in a province with a large ethnic minority population

    Institute of Scientific and Technical Information of China (English)

    DONG Yunchuan; ZHANG Jianxin

    2007-01-01

    Based on a survey of students from different social strata,different family backgrounds and different levels of access to higher education in 10 higher education institutions (HEIs)in Yunnan,an ethnic minority (EM)province,this essay tries to find out the discrepancy in the enrollment opportunity of higher education for children from different strata in the EM province in order to find a breakthrough to narrow the gap.

  20. Using geographical information systems to identify populations in need of improved accessibility to antivenom treatment for snakebite envenoming in Costa Rica.

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    Erik Hansson

    Full Text Available INTRODUCTION: Snakebite accidents are an important health problem in rural areas of tropical countries worldwide, including Costa Rica, where most bites are caused by the pit-viper Bothrops asper. The treatment of these potentially fatal accidents is based on the timely administration of specific antivenom. In many regions of the world, insufficient health care systems and lack of antivenom in remote and poor areas where snakebites are common, means that efficient treatment is unavailable for many snakebite victims, leading to unnecessary mortality and morbidity. In this study, geographical information systems (GIS were used to identify populations in Costa Rica with a need of improved access to antivenom treatment: those living in areas with a high risk of snakebites and long time to reach antivenom treatment. METHOD/PRINCIPAL FINDINGS: Populations living in areas with high risk of snakebites were identified using two approaches: one based on the district-level reported incidence, and another based on mapping environmental factors favoring B. asper presence. Time to reach treatment using ambulance was estimated using cost surface analysis, thereby enabling adjustment of transportation speed by road availability and quality, topography and land use. By mapping populations in high risk of snakebites and the estimated time to treatment, populations with need of improved treatment access were identified. CONCLUSION/SIGNIFICANCE: This study demonstrates the usefulness of GIS for improving treatment of snakebites. By mapping reported incidence, risk factors, location of existing treatment resources, and the time estimated to reach these for at-risk populations, rational allocation of treatment resources is facilitated.

  1. Short communication. Effects of purslane extract on performance, immunity responses and cecal microbial population of broiler chickens

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    Mohammad R. Ghorbani

    2014-10-01

    Full Text Available The aim of present study was to evaluate the effect of purslane extract on performance, cecal microflora composition and immune responses of broiler chickens. One hundred and ninety two 1–day old broiler chicks (Ross 308 were allocated randomly in 4 groups with 4 replicates to receive diets supplemented with 0 (control, 100, 200 and 300 ppm of purslane extract for 42 days. Body weight gain, feed intake (FI and feed conversion ratio were measured weekly and calculated for starter (1-21 d, grower (22-42 d and overall periods (1-42 d. All diets were isocaloric, isonitrogenous and provided ad libitum. Antibody response against sheep red blood cell (SRBC was measured on d-28 and d-42. At the age of 42 d, eight chicks per treatment killed aseptically for enumeration of cecal bacteria. The results of this experiment indicated that FI increased significantly with inclusion of purslane extract in grower and overall period (p≤0.05. Purslane extract did not affect coliform and Escherichia coli populations but increased Lactobacillus population of cecal content significantly (p≤0.05. There were no significant differences in primary and secondary antibody titer against SRBC and no differences among the treatments for relative weight of thymus and spleen (p>0.05. Relative weight of bursa was affected with inclusion of purslane extract in the diet. Therefore, it was concluded that purslane inclusion had a positive significant effect on cecal microflora composition, but had no effect on immune response of broiler chickens.

  2. Progress towards the child mortality millennium development goal in urban sub-Saharan Africa: the dynamics of population growth, immunization, and access to clean water

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    Madise Nyovani

    2007-08-01

    Full Text Available Abstract Background Improvements in child survival have been very poor in sub-Saharan Africa (SSA. Since the 1990s, declines in child mortality have reversed in many countries in the region, while in others, they have either slowed or stalled, making it improbable that the target of reducing child mortality by two thirds by 2015 will be reached. This paper highlights the implications of urban population growth and access to health and social services on progress in achieving MDG 4. Specifically, it examines trends in childhood mortality in SSA in relation to urban population growth, vaccination coverage and access to safe drinking water. Methods Correlation methods are used to analyze national-level data from the Demographic and Health Surveys and from the United Nations. The analysis is complemented by case studies on intra-urban health differences in Kenya and Zambia. Results Only five of the 22 countries included in the study have recorded declines in urban child mortality that are in line with the MDG target of about 4% per year; five others have recorded an increase; and the 12 remaining countries witnessed only minimal decline. More rapid rate of urban population growth is associated with negative trend in access to safe drinking water and in vaccination coverage, and ultimately to increasing or timid declines in child mortality. There is evidence of intra-urban disparities in child health in some countries like Kenya and Zambia. Conclusion Failing to appropriately target the growing sub-group of the urban poor and improve their living conditions and health status – which is an MDG target itself – may result in lack of improvement on national indicators of health. Sustained expansion of potable water supplies and vaccination coverage among the disadvantaged urban dwellers should be given priority in the efforts to achieve the child mortality MDG in SSA.

  3. Evaluation of microbial population dynamics in the co-composting of cow manure and rice straw using high throughput sequencing analysis.

    Science.gov (United States)

    Ren, Guangming; Xu, Xiuhong; Qu, Juanjuan; Zhu, Liping; Wang, Tingting

    2016-06-01

    Microbial population dynamics in co-composting of cow manure and rice straw were evaluated using 16S high throughput sequencing technology. Physicochemical factors, including temperature, pH, nitrogen contents, the ratio of carbon and nitrogen, and germination index, were also determined in this study. 16S high throughput sequencing results showed that bacterial community structure and composition significantly varied in each phase of composting. The major phyla included Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria and Planctomycetes, respectively. Bacteroidetes and Proteobacteria were the most abundant phyla in all phases, and Actinobacteria was just dominant in the mesophilic phase, while Firmicutes and Planctomycetes were ubiquitous. At the genus level, Simiduia, Flavobacterium, unclassified Chitinophagaceae and Flexibacter notably changed in each phase of composting. Bacterial community diversity in the mesophilic phase was higher than that in others based on the Shannon-Wiener index and Simpson diversity index. The ratio of carbon and nitrogen and germination index indicated that the co-composting of cow manure and rice straw reached maturation. The result of nitrogen contents showed that nitrogen loss mainly occurred in the thermophilic phase. In addition, the differences in the distributions of key OTUs between in the late thermophilic phase and the cooling and maturation phase were unobvious compared with other phase's base on the principal component analysis. Redundancy analysis revealed that the changes of nitrogen played a predominant role in the distributions of OTUs during the composting process. PMID:27116967

  4. 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. PMID:26954140

  5. Improving Access to Primary Care for a Growing Latino Population: The Role of Safety Net Providers in the Rural Midwest

    Science.gov (United States)

    Blewett, Lynn A.; Casey, Michelle; Call, Kathleen Thiede

    2004-01-01

    Many rural Midwestern communities are experiencing rapid growth in Latino populations with low rates of health insurance coverage, limited financial resources, language and cultural differences, and special health care needs. We report on 2-day site visits conducted in 2001 and 2002 in 3 communities (Marshalltown, Iowa; Great Bend, Kansas; and…

  6. Access to Adequate Outpatient Depression Care for Mothers in the US: A Nationally Representative Population-Based Study

    OpenAIRE

    Witt, Whitney P.; Keller, Abiola; Gottlieb, Carissa; Litzelman, Kristin; Hampton, John; Maguire, Jonathan; Hagen, Erika W.

    2009-01-01

    Maternal depression is often untreated, resulting in serious consequences for mothers and their children. Factors associated with receipt of adequate treatment for depression were examined in a population-based sample of 2,130 mothers in the USA with depression using data from the 1996-2005 Medical Expenditure Panel Survey. Chi-squared analyses were used to evaluate differences in sociodemographic and health characteristics by maternal depression treatment status (none, some, adequate). Multi...

  7. Differences and determinants in access to essential public health services in China: a case study with hypertension people and under-sixes as target population

    Institute of Scientific and Technical Information of China (English)

    Niu Hongli; Tian Miaomiao; Ma Anning; Wang Chunping; Zhang Liang

    2014-01-01

    Background Since 2009,health reform had launched in China and essential public health services were provided for all residents to ensure service equity and accessibility,and to achieve sustained population-wide health improvement.This study aimed to investigate the differences and determinants among populations with different characteristics access to essential public health services in China,especially hypertension people and children aged 0-6 years.Methods A cross-sectional study with socio-demographic data analysis was undertaken to estimate distribution characteristics of receiving essential public health services of hypertension patients and children.Regular follow-ups and effective blood pressure control reflected the effective management for hypertension patients,and for children,public services provided were vaccination on schedule and regular physical check-up.Logistic regression was used to determine the predictors for effective management.Results A total of 1 505 hypertension patients and 749 children were involved; 39.14% of hypertension participants could control their blood pressure in the normal range,and the rate in urban areas (43.61%) was higher than that in rural (31.88%).And 34.68% of them could receive more than 4 times follow-ups by the medical technician.Of 754 children,79.84% could receive the periodic physical examination and 98.40% had vaccinated regularly.Children living in rural areas were more likely to have regular check-ups (83.96%) and regular vaccination (nearly 99%).Overall,geographic location and education level were the determinants of people access to essential public health services.Conclusions Implementation of the health reform since 2009 has headed China's public health system in the right direction and promoted the improvement of public health system development.Our study highlights the growing needs for more public health services in China,and China's public health system needs to be greatly improved in

  8. Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions.

    Science.gov (United States)

    Lytou, Anastasia; Panagou, Efstathios Z; Nychas, George-John E

    2016-05-01

    The aim of this study was the development of a model to describe the growth kinetics of aerobic microbial population of chicken breast fillets marinated in pomegranate juice under isothermal and dynamic temperature conditions. Moreover, the effect of pomegranate juice on the extension of the shelf life of the product was investigated. Samples (10 g) of chicken breast fillets were immersed in marinades containing pomegranate juice for 3 h at 4 °C following storage under aerobic conditions at 4, 10, and 15 °C for 10 days. Total Viable Counts (TVC), Pseudomonas spp and lactic acid bacteria (LAB) were enumerated, in parallel with sensory assessment (odor and overall appearance) of marinated and non-marinated samples. The Baranyi model was fitted to the growth data of TVC to calculate the maximum specific growth rate (μmax) that was further modeled as a function of temperature using a square root-type model. The validation of the model was conducted under dynamic temperature conditions based on two fluctuating temperature scenarios with periodic changes from 6 to 13 °C. The shelf life was determined both mathematically and with sensory assessment and its temperature dependence was modeled by an Arrhenius type equation. Results showed that the μmax of TVC of marinated samples was significantly lower compared to control samples regardless temperature, while under dynamic temperature conditions the model satisfactorily predicted the growth of TVC in both control and marinated samples. The shelf-life of marinated samples was significantly extended compared to the control (5 days extension at 4 °C). The calculated activation energies (Ea), 82 and 52 kJ/mol for control and marinated samples, respectively, indicated higher temperature dependence of the shelf life of control samples compared to marinated ones. The present results indicated that pomegranate juice could be used as an alternative ingredient in marinades to prolong the shelf life of chicken. PMID:26742613

  9. Access to Difficult-to-reach Population Subgroups: A Family Midwife Based Home Visiting Service for Implementing Nutrition-related Preventive Activities - A Mixed Methods Explorative Study

    Directory of Open Access Journals (Sweden)

    Helena Walz

    2015-08-01

    Full Text Available Health and social inequality are tightly linked and still pose an important public health problem. However, vulnerable and disadvantaged populations are difficult to reach for health-related interventions. Given the long-lasting effects of an adverse, particular nutrition-related, intrauterine and neonatal environment on health development (perinatal programming, an early and easy access is essential for sustainable interventions. The goal of this explorative study was therefore to elucidate whether an existing access of family midwives (FMs to families in need of support could be an option to implement effective public health and nutrition interventions. To that end three research objectives were formulated: (1 to determine whether a discernible impact of home visits by FMs can be described; (2 to identify subgroups among these families in need of more specific interventions; (3 to determine how relevant nutrition-related topics are for both FMs and the supported families. For addressing these objectives a mixed methods design was used: Routine documentation data from 295 families visited by a family midwife (FM were analyzed (secondary analysis, and structured expert interviews with FMs were conducted and analyzed. Study reporting followed the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology statement. Based on the FMs reports, a significant improvement (p < 0.001 regarding psycho-social variables could be determined after the home visits. Single mothers, however, seemed to benefit less from the FMs service compared to their counterparts (p = 0.015. Nutritional counseling was demanded by 89% of the families during the home visits. In addition, nutrition-related topics were reported in the interviews to be of high interest to both families and the FMs. Based on the obtained results it is concluded that FMs home visits offer a promising access to vulnerable and disadvantaged families for implementing nutrition

  10. Challenges in access to health services and its impact on quality of life: a randomised population-based survey within Turkish speaking immigrants in London

    Directory of Open Access Journals (Sweden)

    Topal Kenan

    2012-01-01

    Full Text Available Abstract Background and aim There are a significant number of Turkish speaking immigrants living in London. Their special health issues including women's health, mental health, and alcohol and smoking habits has been assessed. The aim of this study was to explore the ongoing challenges in access to health care services and its impact on Quality of Life of immigrants. Material and methods This cross-sectional population-based study was conducted between March and August 2010 with Turkish immigrants (n = 416 living in London. Of these, 308 (74% were Turkish and 108 (26% were Turkish Cypriots. All healthy or unhealthy adults of 17-65 years of age were enrolled. A structured questionnaire with 44 items in five subcategories and 26-items WHOQOL BREF were used. Results Mean duration of stay for Turkish Cypriots (26.9 ± 13.9 years was significantly longer than Turkish immigrants (13.3 ± 7.5 (p Conclusions The results of this study demonstrate how the health and well-being of members of the Turkish speaking community living in London are affected by social aspects of their lives. Providing culturally competent care and interpretation services and advocacy may improve the accessibility of the health care.

  11. Feasibility and Acceptability of Brighter Bites: A Food Co-Op in Schools to Increase Access, Continuity and Education of Fruits and Vegetables Among Low-Income Populations.

    Science.gov (United States)

    Sharma, Shreela; Helfman, Lisa; Albus, Katherine; Pomeroy, Mike; Chuang, Ru-Jye; Markham, Christine

    2015-08-01

    Intake of fruits and vegetables (F&V) continues to be low in children in the United States. The purpose of this study was to conduct a pilot feasibility evaluation of Brighter Bites, a school-based food co-op to provide access to fresh F&V and nutrition education to low-income children and their families. Brighter Bites is a 16-week school-based food co-op consisting of: (1) Weekly distribution of 50-60 servings of fresh F&V; (2) Weekly bilingual parent handouts and recipe demonstrations; and (3) implementing CATCH, a coordinated school health program in schools. Brighter Bites was pilot tested using a pre-post evaluation design in one charter school in Houston, TX, USA (n = 57 3rd grade parent-child dyads; 94.1 % Hispanic, 91 % low-income). Evaluation, at baseline, midpoint, and post-intervention, included self-reported child and parent surveys on psychosocial factors, dietary habits and mealtime practices. Pearson's Chi square test, Fisher's exact-test or paired t test were used to determine changes pre- to post-intervention (at p sugary drinks with meals, more children asking for F&V as snacks. Process data showed 98 % retention rate and high parent acceptability of program components. Brighter Bites is a promising strategy to increase F&V access and education in low-income populations using existing infrastructure of schools and food banks. PMID:26070256

  12. Effects of Different Rotation Modes on Microbial Population in Gravel Mulched Field%砂田轮作模式对土壤微生物区系的影响

    Institute of Scientific and Technical Information of China (English)

    赵亚慧; 吴宏亮; 康建宏; 许强; 杨金娟; 姚姗; 尹冠华

    2012-01-01

    [目的]研究砂田轮作模式对土壤微生物区系的影响,从而通过制定合理的栽培制度创造良好的土壤生态环境,为促进农业的可持续发展提供理论依据.[方法]对宁夏中卫市香山地区压砂地土壤进行取样,并进行了微生物区系的分析.[结果]西瓜(Citrullus lanatus)与绿豆(Vigna radiata)、南瓜(Cucurbita moschata)、油葵(Helianthus annuus)、西葫芦(Cucurbita pepo L.)、芝麻(Sesamum indicum)轮作,土壤微生物多样性指数均高于西瓜连作.[结论]轮作能有效调节土壤微生物区系,有利于微生物群落的多样性和稳定性的提高,最终改善了土壤的微生态环境,其中以西瓜→南瓜效果最好.%[ Objective] The purpose was to study the effects of different rotation modes on microbial population in gravel mulched field, then create good soil ecological environment by drawing up reasonable cultivation system to provide a theoretical basis for promoting agricultural sustainable development of agriculture, [Method] Soil samples were taken from gravel mulched field in Xiangshan Area, Zhongwei City, Ningxia Hui Autonomous Region and their microbial population was analyzed. [Result] Compared with the watermelon continuous crop, the microbial diversity index was higher in the planting mode of mung bean( Vigna radiata) , pumpkins( Cucurbita moschata) , oil sunflower(Helianthus arm-uus) , squash(Cucurbitapepo L. ) and sesame(Sesamum indicum) rotating with watermelon( Citrultus lanatus). [Conclusion] Rotating effectively adjusts soil microbial population, which is conducive to improving microbial population diversity and stability, and eventually improving the soil ecology environment. Among these rotation modes, squash rotation with watermelon was the best.

  13. A COMPARATIVE ANALYSIS OF THE FINANCIAL COSTS FOR ACCESSING THE SAME BASIC KINESIS-THERAPEUTIC SERVICE AVAILABLE TO THE POPULATION FROM DIFFERENT PARTS OF THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Alexe Dan Iulian

    2014-03-01

    Full Text Available Discriminating the type of ratio between a basic kinesis-therapeutic service available to the population and its corresponding costs in different EU areas. Performing a comparative analysis of the costs for different types of massage for the European market for the relaxation-recovery services can offer new data and reference points to future specialists in these areas when they plan and design their access on such a competitive market. Knowledge of the massage services, of the national economic characteristic, of the principles governing the recovery-rehabilitation –relaxation activities in every EU country can reveal real and positive evidences for the professional career orientation, but also regarding the massage service appreciation within such a large market, as the European Union’s. For the same type of basic kinesis-therapeutic service available to the population (massage, establishing extreme limits for the corresponding costs can represent a challenge difficult to accomplish at the level of EU areas, and this aspect shows, in our opinion, a lack of financial stability and “standardization” of the services for which a kinesiotherapist is trained and specialized.

  14. Cultivation and Genomic, Nutritional, and Lipid Biomarker Characterization of Roseiflexus Strains Closely Related to Predominant In Situ Populations Inhabiting Yellowstone Hot Spring Microbial Mats▿ †

    OpenAIRE

    van der Meer, Marcel T.J.; Klatt, Christian G.; Wood, Jason; Bryant, Donald A.; Bateson, Mary M.; Lammerts, Laurens; Schouten, Stefan; Sinninghe Damsté, Jaap S.; Madigan, Michael T.; Ward, David M.

    2010-01-01

    Roseiflexus sp. strains were cultivated from a microbial mat of an alkaline siliceous hot spring in Yellowstone National Park. These strains are closely related to predominant filamentous anoxygenic phototrophs found in the mat, as judged by the similarity of small-subunit rRNA, lipid distributions, and genomic and metagenomic sequences. Like a Japanese isolate, R. castenholzii, the Yellowstone isolates contain bacteriochlorophyll a, but not bacteriochlorophyll c or chlorosomes, and grow phot...

  15. 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

    Science.gov (United States)

    Kristensen, Matilde B; Metzdorff, Stine B; Bergström, Anders; Damlund, Dina S M; Fink, Lisbeth N; Licht, Tine R; Frøkiær, Hanne

    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 colonized (CONV) mice than in mono-colonized (MC) and germfree (GF) mice, and the CD4+ T cell population established faster in CONV mice. At the day of birth, compared to GF mice, the expression of Cxcl2 was up-regulated and Arg1 down-regulated in livers of CONV mice. This coincided with lower abundance of polylobed cells in the liver of CONV mice. An earlier peak in the expression of the genes Tjp1, Cdh1, and JamA in intestinal epithelial cells of CONV mice indicated an accelerated closure of the epithelial barrier. In conclusion, we have identified an important microbiota-dependent neonatal hematopoietic event, which we suggest impacts the subsequent development of the T cell population in the murine spleen. PMID:26417445

  16. Powders of kudzu, velvetbean, and pine bark added to soil increase microbial population and reduce Southern blight of soybean Pós-secos de kudzu, mucuna e casca de pinus adicionados ao solo aumentam a população microbiana e diminuem a murcha por esclerócio em soja

    OpenAIRE

    Luiz E. B Blum; Rodrigo Rodríguez-Kábana

    2006-01-01

    Southern blight (Sclerotium rolfsii) of soybean (Glycine max) is an important disease throughout the world. Some soil amendments can reduce disease levels by improving soil microbial activity. The main goals of this study were to investigate the effects of soil amendments such as dried powders of kudzu (Pueraria lobata), velvetbean (Mucuna deeringiana), and pine bark (Pinus taeda), on soil microbial population and disease caused by S. rolfsii on soybean. Pine bark, velvetbean (mucuna) and kud...

  17. 广东陈香茶渥堆发酵过程中优势微生物群系的演变%The Evolution of Dominant Microbial Populations in the Guangdong Chenxiang Tea during Pile-Fermentation Process

    Institute of Scientific and Technical Information of China (English)

    方祥; 陈株; 李晶晶; 赵超艺; 李斌; 黄国资

    2011-01-01

    Guangdong Chenxiang Tea is a special black tea of Guangdong province. The dominant microbial populations in the Guangdong Chenxiang Tea were studied. The results showed Aspergillus niger, A. Gloucus, Fenicillium chrysogenum, Candida parapsilosis, Rhizopus sp. And Trichoderma sp. Were the dominant fungi species during pile-fermentation process. P. Chrysogenum accounted for 47.9%~91.9% of the total number of fungi colonies in the beginning of pile-fermentation, but A. Niger grew rapidly and become the absolutely dominant species and accounting for 83.1%~ 97.9% in the late period of fermentation process. The water content had a significant effection on the evolution of microbial populations, reasonably high levels (30%~35%) of moisture promoted the growth and reproduction of A. Niger and Candida parapsilosis, so the microbial populations can be controlled by control of water content so as to improve quality of Chenxiang tea.%对具有地方特色的黑茶品种——广东陈香茶渥堆发酵过程中的优势微生物群系演化进行研究,结果发现其优势种群为黑曲霉(A spergillus niger)、灰绿曲霉(A.gloucus)、产黄青霉(Penicillium chrysogenum)、近平滑假丝酵母(Candida parapsilosis)、根霉(Rhizopus sp.)和木霉(Trichoderma sp.).开潮渥堆开始发酵时,以产黄青霉为主,占47.9%~91.9%.黑曲霉繁殖迅速,在发酵中、后期其占绝对优势(83.1%~97.9%).开潮渥堆时茶堆的含水量对微生物种群演化有显著影响,当其含水量30%~35%时,黑曲霉和酵母的生长繁殖较含水量20%~25%时快.通过水分调控微生物群系,可以达到提高陈香茶品质的目的.

  18. The microbial ocean from genomes to biomes.

    Science.gov (United States)

    DeLong, Edward F

    2009-05-14

    Numerically, microbial species dominate the oceans, yet their population dynamics, metabolic complexity and synergistic interactions remain largely uncharted. A full understanding of life in the ocean requires more than knowledge of marine microbial taxa and their genome sequences. The latest experimental techniques and analytical approaches can provide a fresh perspective on the biological interactions within marine ecosystems, aiding in the construction of predictive models that can interrelate microbial dynamics with the biogeochemical matter and energy fluxes that make up the ocean ecosystem.

  19. 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...

  20. 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...

  1. 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

    , limits the use of these ingredients. The current study aimed to increase the digestibility of dried distillers grains with solubles (DDGS), based on 80% wheat and 20% barley, by fermentation and enzyme addition. Four experimental diets were prepared based on 60% DDGS (fermented or not, without......-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...... to n-FLF (P≤0.03); with the greatest effect on the CelXyl treatment. In conclusion, the digestibility of DDGS in pigs was increased by fermentation. Addition of carbohydrases during fermentation can be a way of further increasing the NSP digestibility of DDGS....

  2. 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

    , 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......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...... 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...

  3. Adding mucins to an in vitro batch fermentation model of the large intestine induces changes in microbial population isolated from porcine feces depending on the substrate.

    Science.gov (United States)

    Tran, T H T; Boudry, C; Everaert, N; Théwis, A; Portetelle, D; Daube, G; Nezer, C; Taminiau, B; Bindelle, J

    2016-02-01

    Adding mucus to in vitro fermentation models of the large intestine shows that some genera, namely lactobacilli, are dependent on host-microbiota interactions and that they rely on mucosal layers to increase their activity. This study investigated whether this dependence on mucus is substrate dependent and to what extent other genera are impacted by the presence of mucus. Inulin and cellulose were fermented in vitro by a fecal inoculum from pig in the presence or not of mucin beads in order to compare fermentation patterns and bacterial communities. Mucins increased final gas production with inulin and shifted short-chain fatty acid molar ratios (P Ruminococcaceae, Bacteroidaceae and Akkermansia spp. Proteobacteria (5.67 vs 0.55%, P Ruminococcaceae decreased. The introduction of mucins affected many microbial genera and fermentation patterns, but from PCA results, the impact of mucus was independent of the fermentation substrate. PMID:26691596

  4. 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.

  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. Understanding differences in access and use of healthcare between international immigrants to Chile and the Chilean-born: a repeated cross-sectional population-based study in Chile

    OpenAIRE

    Cabieses Baltica; Tunstall Helena; Pickett Kate E; Gideon Jasmine

    2012-01-01

    Abstract Introduction International evidence indicates consistently lower rates of access and use of healthcare by international immigrants. Factors associated with this phenomenon vary significantly depending on the context. Some research into the health of immigrants has been conducted in Latin America, mostly from a qualitative perspective. This population-based study is the first quantitative study to explore healthcare provision entitlement and use of healthcare services by immigrants in...

  7. Inferring the contribution of sexual reproduction, migration and off-season survival to the temporal maintenance of microbial populations: a case study on the wheat fungal pathogen Puccinia striiformis f.sp. tritici.

    Science.gov (United States)

    Ali, Sajid; Gladieux, Pierre; Rahman, Hidayatur; Saqib, Muhammad S; Fiaz, Muhammad; Ahmad, Habib; Leconte, Marc; Gautier, Angélique; Justesen, Annemarie F; Hovmøller, Mogens S; Enjalbert, Jérôme; de Vallavieille-Pope, Claude

    2014-02-01

    Understanding the mode of temporal maintenance of plant pathogens is an important domain of microbial ecology research. Due to the inconspicuous nature of microbes, their temporal maintenance cannot be studied directly through tracking individuals and their progeny. Here, we suggest a series of population genetic analyses on molecular marker variation in temporally spaced samples to infer about the relative contribution of sexual reproduction, off-season survival and migration to the temporal maintenance of pathogen populations. We used the proposed approach to investigate the temporal maintenance of wheat yellow rust pathogen, Puccinia striiformis f.sp. tritici (PST), in the Himalayan region of Pakistan. Multilocus microsatellite genotyping of PST isolates revealed high genotypic diversity and recombinant population structure across all locations, confirming the existence of sexual reproduction in this region. The genotypes were assigned to four genetic groups, revealing a clear differentiation between zones with and without Berberis spp., the alternate host of PST, with an additional subdivision within the Berberis zone. The lack of any differentiation between samples across two sampling years, and the very infrequent resampling of multilocus genotypes over years at a given location was consistent with limited over-year clonal survival, and a limited genetic drift. The off-season oversummering population in the Berberis zone, likely to be maintained locally, served as a source of migrants contributing to the temporal maintenance in the non-Berberis zone. Our study hence demonstrated the contribution of both sexual recombination and off-season oversummering survival to the temporal maintenance of the pathogen. These new insights into the population biology of PST highlight the general usefulness of the analytical approach proposed. PMID:24354737

  8. Microbial diversity within Juan de Fuca ridge basement fluids sampled from oceanic borehole observatories

    Science.gov (United States)

    Jungbluth, S.; Bowers, R.; Lin, H.; Hsieh, C.; Cowen, J. P.; Rappé, M.

    2012-12-01

    Three generations of sampling and instrumentation platforms known as Circulation Obviation Retrofit Kit (CORK) observatories affixed to Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP) boreholes are providing unrivaled access to fluids originating from 1.2-3.5 million-years (Myr) old basaltic crust of the eastern flank of the Juan de Fuca ridge. Borehole fluid samples obtained via a custom seafloor fluid pumping and sampling system coupled to CORK continuous fluid delivery lines are yielding critical insights into the biogeochemistry and nature of microbial life inhabiting the sediment-covered basement environment. Direct microscopic enumeration revealed microbial cell abundances that are 2-41% of overlying bottom seawater. Snapshots of basement fluid microbial diversity and community structure have been obtained through small subunit ribosomal RNA (SSU rRNA) gene cloning and sequencing from five boreholes that access a range of basement ages and temperatures at the sediment-basement interface. SSU rRNA gene clones were derived from four different CORK installations (1026B, 1301A, 1362A, and 1362B) accessing relatively warmer (65°C) and older (3.5 Myr) ridge flank, and one location (1025C) accessing relatively cooler (39°C) and younger (1.2 Myr) ridge flank, revealing that warmer basement fluids had higher microbial diversity. A sampling time-series collected from borehole 1301A has revealed a microbial community that is temporally variable, with the dominant lineages changing between years. Each of the five boreholes sampled contained a unique microbial assemblage, however, common members are found from both cultivated and uncultivated lineages within the archaeal and bacterial domains, including meso- and thermophilic microbial lineages involved with sulfur cycling (e.g Thiomicrospira, Sulfurimonas, Desulfocapsa, Desulfobulbus). In addition, borehole fluid environmental gene clones were also closely related to uncultivated lineages

  9. Quantitative Microbial Risk Assessment Tutorial: Installation of Software for Watershed Modeling in Support of QMRA

    Science.gov (United States)

    This tutorial provides instructions for accessing, retrieving, and downloading the following software to install on a host computer in support of Quantitative Microbial Risk Assessment (QMRA) modeling:• SDMProjectBuilder (which includes the Microbial Source Module as part...

  10. The relationship between spatial structure of accessibility and population change in Pearl River Delta%珠江三角洲交通通达性空间格局与人口变化关系

    Institute of Scientific and Technical Information of China (English)

    李涛; 曹小曙; 黄晓燕

    2012-01-01

    Based on the road and railway network data of 1988, 1998 and 2008 in the Pearl River Delta, supported by the GIS software, this paper examines the spatial structure and evolution of major cities accessibility in this region, and quantitatively analyzes the rela- tionship between road and railway accessibility and population change using GAM models. The results are shown as follows. During the study periods, road accessibility of Guang- zhou-Dongguan-Shenzhen line is the highest, gradually decreasing from the center to the surroundings. However, the spatial structure of railway accessibility has changed little, Guangzhou-Foshan areas are the center with the highest accessibility, and the accessibility decreases from the center to the surroundings. Evolution of land transport network in the Pearl River Delta is mainly affected by road network, and rail transport network plays a minor role in land network. There are great differences of accessibility improvement in the two research stages that demonstrate diminishing effects, and the accessibility improve- ment in the first stage (1988-1998) is more outstanding than that in the second stage (1998-2008). The relationship between road-railway traffic and population change is dif- ferent, and roads have significant effect on population change, with its contribution rate with population change being 11.56%, 48.07%, and 44. 92% in the three periods, respectively. The relationship between railway and population change was weak, but after 1990, with the railway network expanded and the standard of railway transport service im- proved, its relationship with population change has gradually strengthened.%基于1988年、1998年、2008年陆路交通网络数据,借助GIS软件,分析了1980年代以来珠三角地区交通网络通达性空间格局的变化,并采用GAM模型,定量分析了1980~2009年期间陆路交通网络与人口变化之间的关系。结果表明:研究时段内,公路交通通

  11. 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.

  12. A microbial perspective of human developmental biology.

    Science.gov (United States)

    Charbonneau, Mark R; Blanton, Laura V; DiGiulio, Daniel B; Relman, David A; Lebrilla, Carlito B; Mills, David A; Gordon, Jeffrey I

    2016-07-01

    When most people think of human development, they tend to consider only human cells and organs. Yet there is another facet that involves human-associated microbial communities. A microbial perspective of human development provides opportunities to refine our definitions of healthy prenatal and postnatal growth and to develop innovative strategies for disease prevention and treatment. Given the dramatic changes in lifestyles and disease patterns that are occurring with globalization, we issue a call for the establishment of 'human microbial observatories' designed to examine microbial community development in birth cohorts representing populations with diverse anthropological characteristics, including those undergoing rapid change. PMID:27383979

  13. Adding mucins to an in vitro batch fermentation model of the large intestine induces changes in microbial population isolated from porcine feces depending on the substrate.

    Science.gov (United States)

    Tran, T H T; Boudry, C; Everaert, N; Théwis, A; Portetelle, D; Daube, G; Nezer, C; Taminiau, B; Bindelle, J

    2016-02-01

    Adding mucus to in vitro fermentation models of the large intestine shows that some genera, namely lactobacilli, are dependent on host-microbiota interactions and that they rely on mucosal layers to increase their activity. This study investigated whether this dependence on mucus is substrate dependent and to what extent other genera are impacted by the presence of mucus. Inulin and cellulose were fermented in vitro by a fecal inoculum from pig in the presence or not of mucin beads in order to compare fermentation patterns and bacterial communities. Mucins increased final gas production with inulin and shifted short-chain fatty acid molar ratios (P inulin was fermented. A more in-depth community analysis indicated that the mucins increased Proteobacteria (0.55 vs 0.25%, P = 0.013), Verrucomicrobia (5.25 vs 0.03%, P = 0.032), Ruminococcaceae, Bacteroidaceae and Akkermansia spp. Proteobacteria (5.67 vs 0.55%, P < 0.001) and Lachnospiraceae (33 vs 10.4%) were promoted in the mucus compared with the broth, while Ruminococcaceae decreased. The introduction of mucins affected many microbial genera and fermentation patterns, but from PCA results, the impact of mucus was independent of the fermentation substrate.

  14. 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.

  15. Coamplification of eukaryotic DNA with 16S rRNA gene-based PCR primers: possible consequences for population fingerprinting of complex microbial communities.

    Science.gov (United States)

    Huys, Geert; Vanhoutte, Tom; Joossens, Marie; Mahious, Amal S; De Brandt, Evie; Vermeire, Severine; Swings, Jean

    2008-06-01

    The main aim of this study was to evaluate the specificity of three commonly used 16S rRNA gene-based polymerase chain reaction (PCR) primer sets for bacterial community analysis of samples contaminated with eukaryotic DNA. The specificity of primer sets targeting the V3, V3-V5, and V6-V8 hypervariable regions of the 16S rRNA gene was investigated in silico and by community fingerprinting of human and fish intestinal samples. Both in silico and PCR-based analysis revealed cross-reactivity of the V3 and V3-V5 primers with the 18S rRNA gene of human and sturgeon. The consequences of this primer anomaly were illustrated by denaturing gradient gel electrophoresis (DGGE) profiling of microbial communities in human feces and mixed gut of Siberian sturgeon. DGGE profiling indicated that the cross-reactivity of 16S rRNA gene primers with nontarget eukaryotic DNA might lead to an overestimation of bacterial biodiversity. This study has confirmed previous sporadic indications in literature indicating that several commonly applied 16S rRNA gene primer sets lack specificity toward bacteria in the presence of eukaryotic DNA. The phenomenon of cross-reactivity is a potential source of systematic error in all biodiversity studies where no subsequent analysis of individual community amplicons by cloning and sequencing is performed.

  16. The reproductive tracts of two malaria vectors are populated by a core microbiome and by gender- and swarm-enriched microbial biomarkers

    Science.gov (United States)

    Segata, Nicola; Baldini, Francesco; Pompon, Julien; Garrett, Wendy S.; Truong, Duy Tin; Dabiré, Roch K.; Diabaté, Abdoulaye; Levashina, Elena A.; Catteruccia, Flaminia

    2016-01-01

    Microbes play key roles in shaping the physiology of insects and can influence behavior, reproduction and susceptibility to pathogens. In Sub-Saharan Africa, two major malaria vectors, Anopheles gambiae and An. coluzzii, breed in distinct larval habitats characterized by different microorganisms that might affect their adult physiology and possibly Plasmodium transmission. We analyzed the reproductive microbiomes of male and female An. gambiae and An. coluzzii couples collected from natural mating swarms in Burkina Faso. 16S rRNA sequencing on dissected tissues revealed that the reproductive tracts harbor a complex microbiome characterized by a large core group of bacteria shared by both species and all reproductive tissues. Interestingly, we detected a significant enrichment of several gender-associated microbial biomarkers in specific tissues, and surprisingly, similar classes of bacteria in males captured from one mating swarm, suggesting that these males originated from the same larval breeding site. Finally, we identified several endosymbiotic bacteria, including Spiroplasma, which have the ability to manipulate insect reproductive success. Our study provides a comprehensive analysis of the reproductive microbiome of important human disease vectors, and identifies a panel of core and endosymbiotic bacteria that can be potentially exploited to interfere with the transmission of malaria parasites by the Anopheles mosquito. PMID:27086581

  17. Fiber digestion, VFA production, and microbial population changes during in vitro ruminal fermentations of mixed rations by monensin-adapted and unadapted microbes

    Science.gov (United States)

    Mixed ruminal microbes were incubated for 24 h in vitro with mixed forage and concentrate rations containing 20% or 30% non-fiber carbohydrates (NFC) to assess in vitro fiber digestibility, fermentation end products, and relative population sizes (RPS, expressed as a percentage of 16S rRNA gene cop...

  18. Microbial ecology on the microcosm level: Activity and population dynamics of methanotrophic bacteria during early succession in a flooded rice field soil

    Science.gov (United States)

    Krause, S.; Frenzel, P.

    2009-04-01

    Methane oxidizing bacteria (methanotrophs) play an important role in natural wetlands and rice fields preventing large amounts of methane from escaping into the atmosphere. The occurrence of both type I and type II methanotrophs in the soil surface layer has been demonstrated in many studies. However, there is no profound understanding which of them are responsible for the oxidizing activity and how they differ ecologically. Hence, a gradient microcosm system was applied simulating oxic-anoxic interfaces of water saturated soils to unravel population dynamics in early succession of methanotrophs in a flooded rice paddy. Additionally, environmental parameters were analyzed to link environment, populations, and their specific activity. We measured pmoA-based (particulate methane monooxygenase) terminal restriction fragment length polymorphism (T-RFLP) profiles both on transcription and population level. DNA T-RFLP patterns showed no major differences in the methanotrophic community structure remaining relatively constant over time. In contrast the active methanotrophic community structure as detected by pmoA mRNA T-RFLP analysis clearly demonstrated a distinct pattern from DNA T-RFLP profiles. While type II represented the most prominent group on the population level it seems to play a minor role on the transcription level. Furthermore there were no clear implications towards a link between soil parameters (e.g. NH4+ concentration) and methanotrophic community structure.

  19. Mapping and introgression of QTL for yield and related traits in two backcross populations derived from Oryza sativa cv. Swarna and two accessions of O. nivara

    Indian Academy of Sciences (India)

    B. P. Mallikarjuna Swamy; K. Kaladhar; G. Ashok Reddy; B. C. Viraktamath; N. Sarla

    2014-12-01

    Advanced backcross QTL (AB-QTL) analysis was carried out in two Oryza nivara-derived BC2F2 populations. For nine traits, we identified 28 QTL in population 1 and 26 QTL in population 2. The two most significant yield-enhancing QTL, yldp9.1 and yldp2.1 showed an additive effect of 16 and 7 g per plant in population 1, while yld2.1 and yld11.1 showed an additive effect of 11 and 10 g per plant in population 2. At least one O. nivara-derived QTL with a phenotypic variance of >15% was detected for seven traits in population 1 and three traits in population 2. The O. nivara-derived QTL ph1.1, nt12.1, nsp1.1, nfg1.1, bm11.1, yld2.1 and yld11.1 were conserved at the same chromosomal locations in both populations. Two major QTL clusters were detected at the marker intervals RM488–RM431 and RM6–RM535 on chromosomes 1 and 2, respectively. The colocation of O. nivara-derived yield QTL with yield meta-QTL on chromosomes 1, 2 and 9 indicates their accuracy and consistency. The major-effect QTL reported in this study are useful for marker-assisted breeding and are also suitable for further fine mapping and candidate gene identification.

  20. Influence of the Application of Sewage Sludge and Presence of Pesticides on the Development of the Microbial Population of the Soil and on the Transformation of Organic Carbon and Nutrient Elements

    Directory of Open Access Journals (Sweden)

    M. E.  Sanchez

    2005-01-01

    Full Text Available The laboratory trial consisted in incubating samples of soil and soil treated with sewage sludge, with the application of organophosphate pesticides with different active ingredients under controlled conditions of temperature and moisture. On the basis of a previous study of the influence of the application of sludge on the degradation of pesticides in the soil, a kinetic study is included of the degradation process and we concentrate on its effects on the development of the microbial population and the mineralization of organic carbon, together with the transformation of the main nutritive elements for plants: nitrogen and phosphorus. Three different active ingredients were used: fenitrothion, diazinon and dimethoate, all of them organophosphates with different chemical structures. From the results, it is to be observed that for all the conditions studied, degradation followed first-order kinetics. The presence of pesticides in the soil produces an increase in micro-organism populations in comparison with the control sample in the different matrices assayed, favouring the mineralization of organic carbon. As for available nitrogen, the predominant form, either ammonia or nitrates, depends on the active ingredient applied. On the other hand, the use of pesticides favours the process of mineralization/solubilization of phosphorus.

  1. Microbial biotechnology.

    Science.gov (United States)

    Demain, A L

    2000-01-01

    For thousands of years, microorganisms have been used to supply products such as bread, beer and wine. A second phase of traditional microbial biotechnology began during World War I and resulted in the development of the acetone-butanol and glycerol fermentations, followed by processes yielding, for example, citric acid, vitamins and antibiotics. In the early 1970s, traditional industrial microbiology was merged with molecular biology to yield more than 40 biopharmaceutical products, such as erythropoietin, human growth hormone and interferons. Today, microbiology is a major participant in global industry, especially in the pharmaceutical, food and chemical industries. PMID:10631778

  2. 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

  3. Microbial Ecosystems, Protection of

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Nelson, K.E.

    2014-01-01

    Synonyms Conservation of microbial diversity and ecosystem functions provided by microbes; Preservation of microbial diversity and ecosystem functions provided by microbes Definition The use, management, and conservation of ecosystems in order to preserve microbial diversity and functioning. Introdu

  4. Influencia de la agricultura de conservación en la temperatura del suelo y su relación con las poblaciones microbianas Influence of conservation agriculture over soil temperature and the relation with microbial populations

    Directory of Open Access Journals (Sweden)

    A. Muñoz

    2009-01-01

    óptimos de temperatura para el crecimiento microbiano en los manejos de agricultura de conservación.The temperature of the soil is a key factor in the growth of the maize, a sensible culture to the temperature variations, with high optimal temperature for germination of the seed, growth of plant and fruition. The conservation agriculture tends to diminish the temperature of the soil, due to the stubbles that are left in surface, in whose decomposition the microorganisms of the soil play a fundamental role, and to the associated increase of humidity this type of management. For a suitable management of soils under conservation agriculture is recommendable the study of the temperature and the microbial populations in the surface horizon. For these reasons, the objective of this study has been to make a comparative study of the oscillations of temperature in different managements from agriculture of conservation as opposed to the obtained with a conventional management, and to determine how affect these variations of temperature to the microbial populations associated to the rhizosphere of the culture. Field experiences have been made in four different managements under a same soil, located in contiguous subparcels; one of direct seeding (DS, two of direct seeding with cover (DSC with different antiquity from implantation and a conventional tillage (CT. It has been made an exhaustive measurement of the temperature of the soil during three years and a monitoring of the evolution of the microbial populations. The analysis of the results allows to conclude that during the period of culture takes place a diminution of the temperature in SD and SDC with respect to LC, with smaller oscillations of temperature for the conservation agriculture. In addition, an increase in the microbial populations associated to SD and SDC with respect to LC is observed, that would indicate the existence of optimal intervals of temperature for the microbial growth in the managements of

  5. Effects of purified lignin and mannan oligosaccharides on intestinal integrity and microbial populations in the ceca and litter of broiler chickens.

    Science.gov (United States)

    Baurhoo, B; Phillip, L; Ruiz-Feria, C A

    2007-06-01

    A study was conducted to evaluate lignin and mannan oligosaccharides as potential alternatives to antibiotic growth promoters in broilers. Dietary treatments included an antibiotic-free diet (CTL-), a positive control (CTL+, 11 mg/kg of virginiamycin), and an antibiotic-free diet containing BioMos (MOS, 0.2% to 21 d and 0.1% thereafter) or Alcell lignin at 1.25% (LL) or 2.5% (HL) of the diet. Each treatment was randomly assigned to 4 floor pen replicates (40 birds each). Body weight and feed conversion were recorded weekly throughout 42 d. Jejunum histology was analyzed at d 14, 28, and 42. At d 28 and 42, cecal contents were assayed for Escherichia coli, Salmonella, lactobacilli, and bifidobacteria, and the litter was analyzed for E. coli and Salmonella. Birds fed the CTL- diet were heavier (Pantibiotics or antibiotic-free diets containing either MOS or lignin. However, birds fed MOS and LL had a comparative advantage over birds fed antibiotics as evidenced by an increased population of beneficial bacteria in the ceca, increased villi height and number of goblet cells in the jejunum, and lower population of E. coli in the litter. PMID:17495075

  6. 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.

  7. Oral chlorhexidine and microbial contamination during endoscopy

    DEFF Research Database (Denmark)

    Donatsky, Anders Meller; Holzknecht, Barbara Juliane; Arpi, Magnus;

    2013-01-01

    BACKGROUND: One of the biggest concerns associated with transgastric surgery is contamination and risk of intra-abdominal infection with microbes introduced from the access route. The purpose of this study was to evaluate the effect of oral decontamination with chlorhexidine on microbial contamin......BACKGROUND: One of the biggest concerns associated with transgastric surgery is contamination and risk of intra-abdominal infection with microbes introduced from the access route. The purpose of this study was to evaluate the effect of oral decontamination with chlorhexidine on microbial...

  8. 大蒜根际土壤微生物数量及酶活性动态研究%Dynamic Study of Microbial Population and Enzyme Activity in Rhizosphere Soil of Allium sativum L.

    Institute of Scientific and Technical Information of China (English)

    周艳丽; 王艳; 李金英; 薛艳杰

    2011-01-01

    [ Objective] The aim was to investigate the changes in rhizosphere microbial population and soil enzyme activities of the two cultivars of Alliurn sativurn L. at different stages. [ Method ] By using white garlic and purple garlic as the experimental materials, the microbial population, and the urease, acid phosphatase, catalase activities in rhizosphere soil at different growth stages were measured. [ Result ] The root exudates of the two garlic cultivars could promote the growth of bacteria, fungi and actinomycetes, and thus indirectly increase the urease,acid phosphatase and catalase activities in rhizosphere soil, thereby improving the turnover and circulation of the soil nutrition elements such as nitrogen and phosphorus and providing a better micro-ecological environment for the later crop. [ Conclusion] The study had provided theoretical basis for the ecological research on garlic used as a preceding crop.%[目的]研究大蒜不同时期根际微生物数量及土壤酶活性的变化.[方法]以白皮蒜和紫皮蒜为试验材料,分别测定不同时期根际微生物数量及土壤脲酶、酸性磷酸酶和过氧化氢酶活性.[结果]各时期2个大蒜品种均促进了根际土壤中细菌、放线菌和真菌的生长,间接提高了根际土壤中脲酶、磷酸酶和过氧化氢酶的活性,从而促进了大蒜根际土壤中氮、磷等营养元素的周转与循环,为下茬作物生长提供了良好的微生态环境.[结论]该研究为大蒜作为一种良好的前茬作物的生态学研究提供理论依据.

  9. The role of gender inequities in women's access to reproductive health care: a population-level study of Namibia, Kenya, Nepal, and India

    Directory of Open Access Journals (Sweden)

    Namasivayam A

    2012-07-01

    Full Text Available Amrita Namasivayam,1 Donatus C Osuorah,2 Rahman Syed,3 Diddy Antai3,41Department of Public Health, Division of Global Health (IHCAR, Karolinska Institute, Stockholm, Sweden; 2Department of Pediatrics, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra, Nigeria; 3Department of Public Health, Division of Social Medicine, Karolinska Institute, Stockholm, Sweden; 4Division of Global Health and Inequalities, The Angels Trust, Abuja, NigeriaBackground: The role of gender inequities in explaining women's access to reproductive health care was examined in four countries (two sub-Saharan African and two South Asian countries. The extent of gender inequities varies across and within countries, and is rooted in the different cultural practices and gender norms within these different countries, and differences in the status and autonomy of women.Methods: Demographic and Health Survey data from women aged 15–49 years within these countries were analyzed with multivariate logistic regression analysis to examine the role of multidimensional characteristics of gender inequities, operationalized as access to skilled antenatal care, tetanus toxoid injection during pregnancy, and access to skilled antenatal care.Results: Significant associations were found between several dimensions of gender inequities (with the exception of decision-making autonomy and reported use of maternal reproductive health care services. Several pathways of influence between the outcome and exposure variables were also identified.Conclusion: Dimensions of gender inequities (with the exception of decision-making autonomy differentially influenced woman's use of reproductive health care services, thus highlighting the urgent need for concerted and sustained efforts to change these harmful traditional values if several of these countries are to meet Millennium Development Goal-5.Keywords: women, gender inequities, reproductive health care, Namibia, Kenya, Nepal, India

  10. Respondent-driven sampling (rds as a new method to access vulnerable populations to hiv: its application in men who have sex with men

    Directory of Open Access Journals (Sweden)

    John H. Estrada M

    2010-11-01

    Full Text Available Approximately 30 million people are living with hiv all around the world in 2010. The most vulnerable hiv/aids groups are sex workers, intravenous drug users, transgender people and population of men who have sex with men (msm. Up to now, the surveillance and behavioral studies on sexual transmitted diseases (sti and hiv have been conducted using intentional sampling methods like the snowball methodology, but this kind of sampling does not achieve representation and does not represent a conclusive method for the study of hidden populations in order to extend and apply its results to the general population. Furthermore, it is necessary to add to this limitation the lack of knowledge about the size of these groups that must face situations of stigma and discrimination. A decade ago a new method was designed to sample hidden and hard to reach populations based on Markov theories and on chain recruitment. This new method is known as respondent-driven sampling (rds and it has been used in several behavioral and hiv prevalence studies. This review article presents the background, the theoretical support and a description of the method. It also analyzes some studies carried out using this new methodology.

  11. A polyphasic approach to study the dynamics of microbial population of an organic wheat sourdough during its conversion to gluten-free sourdough.

    Science.gov (United States)

    Lhomme, Emilie; Mezaize, Sandra; Ducasse, Maren Bonnand; Chiron, Hubert; Champomier-Vergès, Marie-Christine; Chaillou, Stéphane; Zagorec, Monique; Dousset, Xavier; Onno, Bernard

    2014-03-01

    To develop a method for organic gluten-free (GF) sourdough bread production, a long-term and original wheat sourdough was refreshed with GF flours. The dynamics of the sourdough microbiota during five months of back-slopping were analyzed by classical enumeration and molecular methods, including PCR-temporal temperature gel electrophoresis (PCR-TTGE), multiplex PCR, and pulsed field gel electrophoresis (PFGE). The results showed that the yeast counts remained constant, although Saccharomyces cerevisiae, present in the initial wheat sourdough, was no longer detected in the GF sourdough, while lactic acid bacteria (LAB) counts increased consistently. In the first phase, which was aimed at obtaining a GF sourdough from wheat sourdough, Lactobacillus sanfranciscensis, L. plantarum, and L. spicheri were the main LAB species detected. During the second phase, aimed at maintaining the GF sourdough, the L. plantarum and L. spicheri populations decreased whereas L. sanfranciscensis persisted and L. sakei became the predominant species. Multiplex PCRs also revealed the presence of several L. sakei strains in the GF sourdough. In a search for the origin of the LAB species, PCR-TTGE was performed on the flour samples but only L. sanfranciscensis was detected, suggesting a flour origin for this typical sourdough species. Thus, while replacement of the wheat flour by GF flour influenced the sourdough microbiota, some of the original sourdough LAB and yeast species remained in the GF sourdough.

  12. Effectiveness of Phytogenic Feed Additive as Alternative to Bacitracin Methylene Disalicylate on Hematological Parameters, Intestinal Histomorphology and Microbial Population and Production Performance of Japanese Quails.

    Science.gov (United States)

    Manafi, M; Hedayati, M; Khalaji, S

    2016-09-01

    This study was conducted to evaluate the effects of phytogenic additive and antibiotic growth promoter in laying Japanese quails. One hundred and sixty five quails were divided into three groups of 5 replicates and 11 quails (8 females and 3 males) in each replicate. Treatment 1 was fed control diet, treatment 2 was fed control diet supplemented with 0.05% bacitracin methylene disalicylate as antibiotic growth promoter and treatment 3 was fed control diet supplemented with 0.1% phytogenic feed additive (PFA) for two periods of 3 weeks each from 37 to 42 weeks of age. Results showed that egg production, eggshell strength, eggshell weight, villus height and villus height to crypt depth ratio were significantly (p≤0.05) increased and feed consumption, feed conversion ratio, albumen, Haugh unit, cholesterol, low-density lipoprotein, alanine transaminase, gamma glutamyltransferase, alkaline phosphatase, high-density lipoprotein, triglyceride, number of goblet cell, crypt depth and intestinal bacterial population of Coliforms, Salmonella and E. coli were significantly (p≤0.05) decreased in PFA fed group. It is concluded that addition of PFA containing phytomolecules and organic acids as main ingredients could significantly improve the production parameters and the general health of laying quails as an alternative to antibiotic growth promoters. PMID:27189636

  13. Bioremediation of chlorimuron-ethyl-contaminated soil by Hansschlegelia sp. strain CHL1 and the changes of indigenous microbial population and N-cycling function genes during the bioremediation process.

    Science.gov (United States)

    Yang, Liqiang; Li, Xinyu; Li, Xu; Su, Zhencheng; Zhang, Chenggang; Zhang, Huiwen

    2014-06-15

    Long-term and excessive application of the herbicide chlorimuron-ethyl has led to soil degradation and crop rotation barriers. In the current study, we isolated bacterial strain Hansschlegelia sp. CHL1, which can utilize chlorimuron-ethyl as its sole carbon and energy source, and investigated its application in soil bioremediation. Indigenous microbial populations and N-cycling function in the soil were also investigated during the bioremediation process by monitoring the copy numbers of bacterial and fungal marker genes, as well as N-cycling functional genes (nifH, amoA, nirS, and nirK). Results showed that >95% of chlorimuron-ethyl could be degraded within 45 days in soils inoculated with CHL1. Inoculation at two time points resulted in a higher remediation efficiency and longer survival time than a single inoculation. At the end of the 60-day incubation, the copy numbers of most indicator genes were recovered to the level of the control, even in the single-inoculation soils. A double inoculation was necessary for recovery of nifH. However, the abundance of nirK and ammonia-oxidizing bacterial genes were significantly inhibited regardless of inoculum. The results suggested that CHL1 is effective for the remediation of chlorimuron-ethyl-contaminated soil, and could partially reduce the toxic effects of chlorimuron-ethyl on soil microorganisms.

  14. Effect of lactulose supplementation on growth performance, intestinal histomorphology, cecal microbial population, and short-chain fatty acid composition of broiler chickens.

    Science.gov (United States)

    Calik, Ali; Ergün, Ahmet

    2015-09-01

    This study investigated the effects of dietary lactulose supplementation on broiler growth performance, intestinal histomorphology, cecal microflora, and cecal short-chain fatty acid (SCFA) concentrations. A total of 245 one-day-old male broiler chickens were randomly assigned to 5 different treatments, with 7 replicates including 7 birds each. The birds received the same basal diet based on corn--soybean meal, and lactulose was included in the diet at 0, 0.2, 0.4, 0.6, or 0.8% at the expense of corn and/or soybean meal. The body weight gain (linear, P=0.027) and feed conversion (linear, P=0.003) from 0 to 21 d showed significant improvement as dietary lactulose was increased from 0.2 to 0.8%. However, dietary lactulose did not affect broiler performance at the end of the experiment (42 d). Furthermore, intestinal measurements and the goblet cell count of broilers fed a lactulose-containing diet differed from those of birds fed a diet that did not contain lactulose. In addition, a significant quadratic response in the Lactobacillus count (P≤0.001) was observed at 42 d on increasing the level of lactulose. The cecal coliform bacterial population was not affected by the dietary treatments. Supplementation with lactulose significantly increased the concentrations of acetate, propionate, butyrate, and total SCFA measured on d 7 and d 42. In conclusion, inclusion of lactulose in the diet can enhance broiler performance and intestinal morphology by selectively stimulating intestinal microflora and increasing cecal SCFA concentrations. PMID:26188035

  15. Factores que inciden en el acceso de la población desplazada a las instituciones prestadoras de servicios de salud en Colombia Factors affecting access to health care institutions by the internally displaced population in Colombia

    Directory of Open Access Journals (Sweden)

    Amparo Susana Mogollón-Pérez

    2008-04-01

    Full Text Available En Colombia, el desplazamiento por conflicto armado genera importantes repercusiones económicas y sociales, que afectan, entre otros, a la salud. A pesar de los esfuerzos normativos, el acceso a los servicios de salud de la población desplazada es limitado. Con el objetivo de analizar los factores que desde las instituciones inciden en el acceso potencial de la población desplazada a los servicios de salud, se desarrolló un estudio cualitativo descriptivo, exploratorio, mediante 81 entrevistas individuales semiestructuradas a actores principales. Una insuficiente financiación y dificultades de los proveedores para recibir el pago de las aseguradoras, junto a las indefiniciones y límites del aseguramiento del Sistema General de Seguridad Social en Salud, son las principales barreras al acceso a la atención en salud de la población desplazada. Acceso que también se ve afectado por los numerosos procedimientos establecidos para la atención, la escasa coordinación inter e intrasectorial y los limitados recursos de las instituciones prestadoras de servicios de salud de carácter público. Se requiere una acción gubernamental efectiva que garantice el derecho a la salud en este colectivo.In Colombia, the on-going armed conflict causes displacement of thousands of persons that suffer its economic, social, and health consequences. Despite government regulatory efforts, displaced people still experience serious problems in securing access to health care. In order to analyze the institutional factors that affect access to health care by the internally displaced population, a qualitative, exploratory, and descriptive study was carried out by means of semi-structured individual interviews with a criterion sample of stakeholders (81. A narrative content analysis was performed, with mixed generation of categories and segmentation of data by themes and informants. Inadequate funding, providers' problems with reimbursement by insurers, and lack of

  16. Access Denied

    Science.gov (United States)

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  17. Respondent-driven sampling (rds) as a new method to access vulnerable populations to hiv: its application in men who have sex with men

    OpenAIRE

    John H. Estrada M; Leonardo Vargas R

    2010-01-01

    Approximately 30 million people are living with hiv all around the world in 2010. The most vulnerable hiv/aids groups are sex workers, intravenous drug users, transgender people and population of men who have sex with men (msm). Up to now, the surveillance and behavioral studies on sexual transmitted diseases (sti) and hiv have been conducted using intentional sampling methods like the snowball methodology, but this kind of sampling does not achieve representation and does not represent a co...

  18. Genetic divergence among populations and accessions of the spineless peach palm from Pampa Hermosa landrace used in the heart-of-palm agribusiness in Brazil

    OpenAIRE

    Alessandro Alves-Pereira; Clement, Charles R.; Doriane Picanço-Rodrigues

    2012-01-01

    Although originally domesticated for its fruit, exploitation of the peach palm (Bactris gasipaes Kunth) in the production of gourmet heart-of-palm has also become an important activity, hence the need for improved material for large-scale production, on employing the Pampa Hermosa landrace as the seed source. In this study 11 microsatellite markers were used to evaluate genetic divergence among 96 elite plants representing four populations of spineless peach palm from the above cited source. ...

  19. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Coates, J.D.; Chisholm, J.L.

    1993-05-01

    A multi-well microbially enhanced oil recovery field pilot has been performed in the Southeast Vassar Vertz Sand Unit in Payne County, Oklahoma. The primary emphasis of the experiment was preferential plugging of high permeability zones for the purpose of improving waterflood sweep efficiency. Studies were performed to determine reservoir chemistry, ecology, and indigenous bacteria populations. Growth experiments were used to select a nutrient system compatible with the reservoir that encouraged growth of a group of indigenous nitrate-using bacteria and inhibit growth of sulfate-reducing bacteria. A specific field pilot area behind an active line drive waterflood was selected. Surface facilities were designed and installed. Injection protocols of bulk nutrient materials were prepared to facilitate uniform distribution of nutrients within the pilot area. By the end of December, 1991, 82.5 tons (75.0 tonnes) of nutrients had been injected in the field. A tracer test identified significant heterogeneity in the SEVVSU and made it necessary to monitor additional production wells in the field. The tracer tests and changes in production behavior indicate the additional production wells monitored during the field trial were also affected. Eighty two and one half barrels (13.1 m[sup 3]) of tertiary oil have been recovered. Microbial activity has increased CO[sub 2] content as indicated by increased alkalinity. A temporary rise in sulfide concentration was experienced. These indicate an active microbial community was generated in the field by the nutrient injection. Pilot area interwell pressure interference test results showed that significant permeability reduction occurred. The interwell permeabilities in the pilot area between the injector and the three pilot production wells were made more uniform which indicates a successful preferential plugging enhanced oil recovery project.

  20. Relevance of antarctic microbial ecosystems to exobiology

    Science.gov (United States)

    Mckay, Christopher P.

    1993-01-01

    Antarctic microbial ecosystems which provide biological and physical analogs that can be used in exobiology are studied. Since the access to extraterrestrial habitats is extremely difficult, terrestrial analogs represent the best opportunity for both formulation and preliminary testing of hypothesis about life. Antarctica, as one of few suitable environments on earth is considered to be a major locus of progress in exobiology.

  1. The association between self-reported grocery store access, fruit and vegetable intake, sugar-sweetened beverage consumption, and obesity in a racially diverse, low-income population

    Directory of Open Access Journals (Sweden)

    Lauren Nichol Gase

    2014-11-01

    Full Text Available This study sought to examine the relationship between self-reported time and distance to the nearest retail grocery store, healthy and unhealthy food consumption, and objectively measured body mass index. We conducted a survey with 1,503 racially diverse, low-income residents at five public health centers in Los Angeles County. Most participants reported shopping at a supermarket (86.7% and driving (59.9% to their usual source for groceries. Over half reported living less than a mile from (58.9% and traveling five minutes or less to reach (50.3% the nearest grocery store. In the multivariable regression models, neither self-reported distance nor time to the nearest grocery store was consistently associated with fruit and vegetable intake, sugar-sweetened beverage consumption, or body mass index. Results suggest the need to consider access and quality as well as urban planning and transportation, when examining the relationship between the retail food environment and health outcomes.

  2. For patients with breast cancer, geographic and social disparities are independent determinants of access to specialized surgeons. A eleven-year population-based multilevel analysis

    Directory of Open Access Journals (Sweden)

    Gentil Julie

    2012-08-01

    Full Text Available Abstract Background It has been shown in several studies that survival in cancer patients who were operated on by a high-volume surgeon was better. Why then do all patients not benefit from treatment by these experienced surgeons? The aim of our work was to study the hypothesis that in breast cancer, geographical isolation and the socio-economic level have an impact on the likelihood of being treated by a specialized breast-cancer surgeon. Methods All cases of primary invasive breast cancer diagnosed in the Côte d’Or from 1998 to 2008 were included. Individual clinical data and distance to the nearest reference care centre were collected. The Townsend Index of each residence area was calculated. A Log Rank test and a Cox model were used for survival analysis, and a multilevel logistic regression model was used to determine predictive factors of being treated or not by a specialized breast cancer surgeon. Results Among our 3928 patients, the ten-year survival of the 2931 (74.6 % patients operated on by a high-volume breast cancer surgeon was significantly better (LogRank p  Conclusions A disadvantageous socio-economic environment, a rural lifestyle and living far from large specialized treatment centres were significant independent predictors of not gaining access to surgeons specialized in breast cancer. Not being treated by a specialist surgeon implies a less favourable outcome in terms of survival.

  3. Microbial community modeling using reliability theory.

    Science.gov (United States)

    Zilles, Julie L; Rodríguez, Luis F; Bartolerio, Nicholas A; Kent, Angela D

    2016-08-01

    Linking microbial community composition with the corresponding ecosystem functions remains challenging. Because microbial communities can differ in their functional responses, this knowledge gap limits ecosystem assessment, design and management. To develop models that explicitly incorporate microbial populations and guide efforts to characterize their functional differences, we propose a novel approach derived from reliability engineering. This reliability modeling approach is illustrated here using a microbial ecology dataset from denitrifying bioreactors. Reliability modeling is well-suited for analyzing the stability of complex networks composed of many microbial populations. It could also be applied to evaluate the redundancy within a particular biochemical pathway in a microbial community. Reliability modeling allows characterization of the system's resilience and identification of failure-prone functional groups or biochemical steps, which can then be targeted for monitoring or enhancement. The reliability engineering approach provides a new perspective for unraveling the interactions between microbial community diversity, functional redundancy and ecosystem services, as well as practical tools for the design and management of engineered ecosystems. PMID:26882268

  4. Mathematical modeling of microbial growth in milk

    Directory of Open Access Journals (Sweden)

    Jhony Tiago Teleken

    2011-12-01

    Full Text Available A mathematical model to predict microbial growth in milk was developed and analyzed. The model consists of a system of two differential equations of first order. The equations are based on physical hypotheses of population growth. The model was applied to five different sets of data of microbial growth in dairy products selected from Combase, which is the most important database in the area with thousands of datasets from around the world, and the results showed a good fit. In addition, the model provides equations for the evaluation of the maximum specific growth rate and the duration of the lag phase which may provide useful information about microbial growth.

  5. EVIDENCE FOR MICROBIAL ENHANCED ELECTRICAL CONDUCTIVITY IN HYDROCARBON-CONTAMINATED SEDIMENTS

    Science.gov (United States)

    Electrical conductivity of sediments during microbial mineralization of diesel was investigated in a mesoscale column experiment consisting of biotic contaminated and uncontaminated columns. Microbial population numbers increased with a clear pattern of depth zonation within the ...

  6. Fundamentals of microbial community resistance and resilience

    Directory of Open Access Journals (Sweden)

    Ashley eShade

    2012-12-01

    Full Text Available Microbial communities are at the heart of all ecosystems, and yet microbial community behavior in disturbed environments remains difficult to measure and predict. Understanding the drivers of microbial community stability, including resistance (insensitivity to disturbance and resilience (the rate of recovery after disturbance is important for predicting community response to disturbance. Here, we provide an overview of the concepts of stability that are relevant for microbial communities. First, we highlight insights from ecology that are useful for defining and measuring stability. To determine whether general disturbance responses exist for microbial communities, we next examine representative studies from the literature that investigated community responses to press (long-term and pulse (short-term disturbances in a variety of habitats. Then we discuss the biological features of individual microorganisms, of microbial populations, and of microbial communities that may govern overall community stability. We conclude with thoughts about the unique insights that systems perspectives - informed by meta-omics data- may provide about microbial community stability.

  7. Sprawl and Accessibility

    Directory of Open Access Journals (Sweden)

    Robert Bruegmann

    2008-07-01

    Full Text Available This essay argues that many of the assumptions that have been made about sprawl are misleading or just wrong. Nowhere has this been more the case than in debates about transportation and access. Because of this, it is not surprising that a good many of the policies advocated by proponents of Smart Growth would almost certainly lead to reduced mobility and impaired accessibility for a large part of the population. At very least, the debates over sprawl have pitted private vs. public transportation in a way that has contributed to serious underfunding of transportation infrastructure of all kinds.

  8. Universality of human microbial dynamics

    Science.gov (United States)

    Bashan, Amir; Gibson, Travis E.; Friedman, Jonathan; Carey, Vincent J.; Weiss, Scott T.; Hohmann, Elizabeth L.; Liu, Yang-Yu

    2016-06-01

    Human-associated microbial communities have a crucial role in determining our health and well-being, and this has led to the continuing development of microbiome-based therapies such as faecal microbiota transplantation. These microbial communities are very complex, dynamic and highly personalized ecosystems, exhibiting a high degree of inter-individual variability in both species assemblages and abundance profiles. It is not known whether the underlying ecological dynamics of these communities, which can be parameterized by growth rates, and intra- and inter-species interactions in population dynamics models, are largely host-independent (that is, universal) or host-specific. If the inter-individual variability reflects host-specific dynamics due to differences in host lifestyle, physiology or genetics, then generic microbiome manipulations may have unintended consequences, rendering them ineffective or even detrimental. Alternatively, microbial ecosystems of different subjects may exhibit universal dynamics, with the inter-individual variability mainly originating from differences in the sets of colonizing species. Here we develop a new computational method to characterize human microbial dynamics. By applying this method to cross-sectional data from two large-scale metagenomic studies—the Human Microbiome Project and the Student Microbiome Project—we show that gut and mouth microbiomes display pronounced universal dynamics, whereas communities associated with certain skin sites are probably shaped by differences in the host environment. Notably, the universality of gut microbial dynamics is not observed in subjects with recurrent Clostridium difficile infection but is observed in the same set of subjects after faecal microbiota transplantation. These results fundamentally improve our understanding of the processes that shape human microbial ecosystems, and pave the way to designing general microbiome-based therapies.

  9. Designing the Microbial Research Commons

    Energy Technology Data Exchange (ETDEWEB)

    Uhlir, Paul F. [Board on Research Data and Information Policy and Global Affairs, Washington, DC (United States)

    2011-10-01

    Recent decades have witnessed an ever-increasing range and volume of digital data. All elements of the pillars of science--whether observation, experiment, or theory and modeling--are being transformed by the continuous cycle of generation, dissemination, and use of factual information. This is even more so in terms of the re-using and re-purposing of digital scientific data beyond the original intent of the data collectors, often with dramatic results. We all know about the potential benefits and impacts of digital data, but we are also aware of the barriers, the challenges in maximizing the access, and use of such data. There is thus a need to think about how a data infrastructure can enhance capabilities for finding, using, and integrating information to accelerate discovery and innovation. How can we best implement an accessible, interoperable digital environment so that the data can be repeatedly used by a wide variety of users in different settings and with different applications? With this objective: to use the microbial communities and microbial data, literature, and the research materials themselves as a test case, the Board on Research Data and Information held an International Symposium on Designing the Microbial Research Commons at the National Academy of Sciences in Washington, DC on 8-9 October 2009. The symposium addressed topics such as models to lower the transaction costs and support access to and use of microbiological materials and digital resources from the perspective of publicly funded research, public-private interactions, and developing country concerns. The overall goal of the symposium was to stimulate more research and implementation of improved legal and institutional models for publicly funded research in microbiology.

  10. Accessible Knowledge - Knowledge on Accessibility

    DEFF Research Database (Denmark)

    Kirkeby, Inge Mette

    2015-01-01

    Although serious efforts are made internationally and nationally, it is a slow process to make our physical environment accessible. In the actual design process, architects play a major role. But what kinds of knowledge, including research-based knowledge, do practicing architects make use of when...... designing accessible environments? The answer to the question is crucially important since it affects how knowledge is distributed and how accessibility can be ensured. In order to get first-hand knowledge about the design process and the sources from which they gain knowledge, 11 qualitative interviews...... were conducted with architects with experience of designing for accessibility. The analysis draws on two theoretical distinctions. The first is research-based knowledge versus knowledge used by architects. The second is context-independent knowledge versus context-dependent knowledge. The practitioners...

  11. FERMENTATION CHARACTERISTIC AND POPULATION DYNAMICS OF MICROBIAL SYSTEM FLW-1 IN FED-BATCH EXPERIMENT%复合菌系FLW-1在分批补料中的发酵特性及其种群动态

    Institute of Scientific and Technical Information of China (English)

    郑国香; 李文哲; 关正军; 刘震东; 刘爽; 郑文玲

    2011-01-01

    以稻草为唯一碳源,从堆肥的高温期样品中成功定向筛选出一组复合菌系(命名为FLW-1),该复合菌系具有较强的遗传稳定性和pH缓冲能力.模拟生产实践进行连续批次补料实验,结果表明:复合菌系FLW-1适于微好氧环境发酵,在24h内DO值由最初的4.50mg/L迅速降为0.25mg/L,之后到发酵结束DO值一直维持在0.05~0.10mg/L之间,其主要的发酵液相末端产物中90%以上是乙酸,这对后续产甲烷相的产气提高起到至关重要的作用.其连续发酵过程中微生物种群的动态结果显示,耐高温的短小芽孢杆菌类和具有高聚物强降解能力的抗热厌氧梭菌属是复合菌系降解底物的主要微生物类群.%A microbial system, named FLW-1 which has better genetic fidelity and pH buffer ability, was obtained directionally from high-temperature compost sample with the straw being only carbon sources. The batch-fed experiment simulating production practice was carried out and the results showed that FLW-1 was suitable for microaero-philic environment, which dissolved oxygen value (DO) dropped rapidly from 4. 50mg/L to 0. 25mg/L in 24h, and then always kept at 0. 05-0. 10mg/L until fermentation end. Furthermore, over 90% of main liquid end products were the acetic acid, which will play key role in improving biogas production in down-stream process of methane phase. The dynamics results of microbe' s population also showed that main microbe population degrading substrates were some Bacillus pumilus with high temperature-tolerancing ability and some Clostridium with better polymer degradation and heat resistance capability during continuous fermentation.

  12. Genetic divergence among populations and accessions of the spineless peach palm from Pampa Hermosa landrace used in the heart-of-palm agribusiness in Brazil

    Directory of Open Access Journals (Sweden)

    Alessandro Alves-Pereira

    2012-01-01

    Full Text Available Although originally domesticated for its fruit, exploitation of the peach palm (Bactris gasipaes Kunth in the production of gourmet heart-of-palm has also become an important activity, hence the need for improved material for large-scale production, on employing the Pampa Hermosa landrace as the seed source. In this study 11 microsatellite markers were used to evaluate genetic divergence among 96 elite plants representing four populations of spineless peach palm from the above cited source. Genetic variability was high (H T = 0.82. The low levels of divergence [F ST (0.023, G ST' (0.005] and the high number of migrants (Nm -3.8 to 52.2 indicated significant interpopulation gene flow. Some of the plants presented high levels of genetic divergence, but the plants were grouped independently of their geographic origins. When combined with morpho-agronomic evaluation, the results found could substantially contribute towards mounting an efficient tool for obtaining superior genotypes with wide genetic variability for improvement programs.

  13. Genetic divergence among populations and accessions of the spineless peach palm from Pampa Hermosa landrace used in the heart-of-palm agribusiness in Brazil.

    Science.gov (United States)

    Alves-Pereira, Alessandro; Clement, Charles R; Picanço-Rodrigues, Doriane

    2012-04-01

    Although originally domesticated for its fruit, exploitation of the peach palm (Bactris gasipaes Kunth) in the production of gourmet heart-of-palm has also become an important activity, hence the need for improved material for large-scale production, on employing the Pampa Hermosa landrace as the seed source. In this study 11 microsatellite markers were used to evaluate genetic divergence among 96 elite plants representing four populations of spineless peach palm from the above cited source. Genetic variability was high (H(T) = 0.82). The low levels of divergence [F(ST) (0.023), G(ST)' (0.005)] and the high number of migrants (Nm - 3.8 to 52.2) indicated significant interpopulation gene flow. Some of the plants presented high levels of genetic divergence, but the plants were grouped independently of their geographic origins. When combined with morpho-agronomic evaluation, the results found could substantially contribute towards mounting an efficient tool for obtaining superior genotypes with wide genetic variability for improvement programs.

  14. Belém’s built form and its developments to the formation of a system of open spaces accessible to population

    Directory of Open Access Journals (Sweden)

    Ana Claudia Duarte Cardoso

    2016-07-01

    Full Text Available This paper presents a characterization of the built space of Belém highlighting, its estuarine condition, physical geography and its economic, social and spacial development. It is based on Quapá-SEL Workshop conclusions held in Belém, in May 2015, in which teachers and students from São Paulo and Pará Federal Universities assessed the conditions of urban open spaces of the city. The results highlight a disarticulation between real estate agents strategies and of urban management towards structuring an Open Spaces System (SEL in Portuguese, as well as its limited appropriation by the population. There is a remarkable differentiation between the landscapes of central area in opposition / contraposition to that at the city’s expansion area. This debate showed how much permanent preservation areas on the banks of inland rivers and islands (the main green spaces of the city and main linkage with the Amazonian biome, with its landscape potentials, have been unevenly appropriated in the city, through gentrification.

  15. Response of microbial community structure to microbial plugging in a mesothermic petroleum reservoir in China.

    Science.gov (United States)

    Zhang, Fan; She, Yue Hui; Ma, Sha Sha; Hu, Ji Ming; Banat, Ibrahim M; Hou, Du Jie

    2010-12-01

    Microbial plugging, a microbial enhancement of oil recovery (MEOR) technique, has been applied in a candidate oil reservoir of Daqing Oil Field (China). The goal of this study is to monitor the survival of injected bacteria and reveal the response of microbial communities in field trial of microbial plugging through injection of selected microbial culture broth and nutrients. Culture-dependent enrichment and culture-independent 16S rDNA clone library methods were used. The results show that it was easy to activate targeted biopolymer-producing bacteria in a laboratory environment, and it was difficult for injected exogenous bacteria to survive. In addition, microbial communities in the oil reservoir also changed before and after the field trial. However, microbial communities, activated by fermentative medium for biopolymer-producing bacteria, appeared to show greater differences in the laboratory than in the natural reservoir. It was concluded that microbial populations monitoring was important to MEOR; results of response of microbial communities could provide a guide for the future field trials. PMID:20803140

  16. Response of microbial community structure to microbial plugging in a mesothermic petroleum reservoir in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan; Hou, Du Jie [Ministry of Education, China Univ. of Geosciences, Beijing (China). Key Lab. of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism; She, Yue Hui [Wuhan Univ. (China). College of Chemistry and Molecular Sciences; Yangtze Univ., Hubei (China). College of Chemistry and Environmental Engineering; Ma, Sha Sha [Yangtze Univ., Hubei (China). College of Chemistry and Environmental Engineering; Hu, Ji Ming [Wuhan Univ. (China). College of Chemistry and Molecular Sciences; Banat, Ibrahim M. [Ulster Univ., Coleraine (Ireland). School of Biomedical Sciences

    2010-12-15

    Microbial plugging, a microbial enhancement of oil recovery (MEOR) technique, has been applied in a candidate oil reservoir of Daqing Oil Field (China). The goal of this study is to monitor the survival of injected bacteria and reveal the response of microbial communities in field trial of microbial plugging through injection of selected microbial culture broth and nutrients. Culture-dependent enrichment and culture-independent 16S rDNA clone library methods were used. The results show that it was easy to activate targeted biopolymer-producing bacteria in a laboratory environment, and it was difficult for injected exogenous bacteria to survive. In addition, microbial communities in the oil reservoir also changed before and after the field trial. However, microbial communities, activated by fermentative medium for biopolymer-producing bacteria, appeared to show greater differences in the laboratory than in the natural reservoir. It was concluded that microbial populations monitoring was important to MEOR; results of response of microbial communities could provide a guide for the future field trials. (orig.)

  17. Populações microbianas em solo agrícola sob aplicação de lodos de curtume Microbial populations affected by the soil disposal of tannery sludge

    Directory of Open Access Journals (Sweden)

    Luiz Ermindo Cavallet

    2008-12-01

    estado natural.Tannery residues are potential pollution sources in several regions of Brazil, mainly in the State of Rio Grande do Sul. One of the alternatives for the final destination of the sludge resulting from the waste water treatment of tanning industries is the disposal and recycling in the soil. To evaluate the effects of two waste types originated from primary treatment of tannery residual water on soil microbial populations, an open air pot experiment was carried out in a Paleudult soil with ten percent clay from Estância Velha, Rio Grande do Sul State, Brazil, where several tannery industries are located. Mineral fertilization was compared to sludge application of 15, 30 and 60 t ha-1 of sludge originated either from tannin or Cr tanning agents. One treatment with cattle manure and a control were also included. Chromium soil, organic C concentrations, pH and bacteria, fungi and actinomyces populations were determined. Biological degradation was efficient for sludge with Cr up to 60 t ha-1 level and for tannin sludge up to 30 t ha-1 dose. Except for the sludge with Cr on the fungus population, the bacteria, fungi and actinomyces populations were stimulated by tannery sludge application. Due to the organic matter concentration in the soil, bacteria microbial populations were stimulated more than fungi and actinomyces. Chromium, pH and organic C increased as a result of the soil disposal of tannery sludges. The application of both tannery residues did not decrease the biological degradation process when compared to normal soil levels.

  18. Open access

    CERN Document Server

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder consent, and many authors, musicians, filmmakers, and other creators who depend on royalties are understandably unwilling to give their consent. But for 350 years, scholars have written peer-reviewed journal articles for impact, not for money, and are free to consent to open access without losing revenue. In this concise introduction, Peter Suber tells us what open access is and isn't, how it benefits authors and readers of research, how we pay for it, how it avoids copyright problems, how it has moved from the periphery to the mainstream, and what its future may hold. Distilling a decade of Suber's influential writing and thinking about open access, this is the indispe...

  19. Effects of temperature on microbial transformation of organic matter - comparing stories told by purified enzyme assays, chemostat experiments and soils

    Science.gov (United States)

    Lehmeier, C.; Min, K.; Good, H. J.; Billings, S. A.

    2015-12-01

    Temperature (T) is a major determinant of microbial decomposition of soil organic matter (SOM). Quantifying T responses of microbial C fluxes is crucial to improve predictions of SOM dynamics and atmospheric CO2 concentrations, but interpretation of experimental data is complicated by many properties inherent to soils. Comparing such data with complementary, reductionist experiments can help to identify basic mechanisms and interpret soil measurements. We quantified T effects on activity levels (i.e., rates of substrate cleavage) of microbial extracellular enzymes β-glucosidase (BGase) and β-N-acetyl glucosaminidase (NAGase), and on rates of CO2 efflux in soil incubations. We compare the results to those derived from purified enzyme assays, and to measurements of microbial respiration rates in continuous-flow chemostat culture in which a population of the soil bacterium Pseudomonas fluorescens was grown on medium with similar C:N ratio as the incubated SOM (10:1). Activity levels of both BGase and NAGase decreased by 80% between 25 and 5 °C. These T responses were higher than predictions from intrinsic (i.e., maximum) T responses in purified assays of BGase (minus 50%) and NAGase (minus 67%). This suggests that factors like physical access to substrate or reduced microbial production of enzymes constrained substrate decomposition rates in the soils relatively more at low than at high T. In chemostats, (mass-)specific bacterial respiration rate at T 14.5 °C was 50% of the rate observed at 26.5 °C; in contrast, CO2 efflux from the soil incubations decreased by only ~25% from 25 to 15 °C. The reason for this discrepancy can be manifold, including changes in microbial community composition, but results from ongoing measurements of microbial biomass in the soil samples will allow a closer comparison of these respiration rate responses. Our efforts highlight the significance of experimenting across scales and complexity for a better understanding of SOM dynamics.

  20. Hemodialysis access - self care

    Science.gov (United States)

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - hemodialysis access; dialysis - hemodialysis access

  1. Access French

    CERN Document Server

    Grosz, Bernard

    2014-01-01

    Access is the major new language series designed with the needs of today's generation of students firmly in mind. Whether learning for leisure or business purposes or working towards a curriculum qualification, Access French is specially designed for adults of all ages and gives students a thorough grounding in all the skills required to understand, speak, read and write contemporary French from scratch. The coursebook consists of 10 units covering different topic areas, each of which includes Language Focus panels explaining the structures covered and a comprehensive glossary. Learning tips

  2. Access to legal abortion.

    Science.gov (United States)

    1993-10-01

    Countries are grouped by the nature and extent of access to legal abortion. The categories include abortion on demand, for social reasons, for health reasons, for rape or incest or to save a mother's life, and only to save a mother's life. Abortion on demand is available for about 40% of the world's population and may have restrictions, such as parental consent or approval of state committees or physicians. There are 22 countries in Europe, 12 in the former Soviet Union, four in Asia, four in the Americas, one in the Middle East (Turkey), and one in Africa (Tunisia) which provide access to early abortion on demand. Abortion for social and economic reasons is available to 21% of the world's population in five countries in Asia, three in Europe (Great Britain, Finland, and Hungary), and one in Africa (Zambia). Abortion for health reasons is available to 16% of the world's population located in 21 countries in Africa, eight in the Americas, seven in Asia, five in Europe, and four in the Middle East. Laws governing about 5% of the world's population permit abortion only in the case of rape, incest, or when a mother's life is in danger (Brazil, Mexico, and Sudan). 18% of the world's population is covered by laws which permit an abortion only when a mother's life is in danger; this includes 19 countries in Africa, 11 in the Americas, nine in Asia, seven in the Middle East, and one in Europe (Ireland). PMID:12287145

  3. Microfluidics and microbial engineering.

    Science.gov (United States)

    Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

    2016-02-01

    The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

  4. Childhood microbial keratitis

    Directory of Open Access Journals (Sweden)

    Abdullah G Al Otaibi

    2012-01-01

    Conclusion: Children with suspected microbial keratitis require comprehensive evaluation and management. Early recognition, identifying the predisposing factors and etiological microbial organisms, and instituting appropriate treatment measures have a crucial role in outcome. Ocular trauma was the leading cause of childhood microbial keratitis in our study.

  5. Microbial Metabolism in Serpentinite Fluids

    Science.gov (United States)

    Crespo-Medina, M.; Brazelton, W. J.; Twing, K. I.; Kubo, M.; Hoehler, T. M.; Schrenk, M. O.

    2013-12-01

    Serpentinization is the process in which ultramafic rocks, characteristic of the upper mantle, react with water liberating mantle carbon and reducing power to potenially support chemosynthetic microbial communities. These communities may be important mediators of carbon and energy exchange between the deep Earth and the surface biosphere. Our work focuses on the Coast Range Ophiolite Microbial Observatory (CROMO) in Northern California where subsurface fluids are accessible through a series of wells. Preliminary analyses indicate that the highly basic fluids (pH 9-12) have low microbial diversity, but there is limited knowledge about the metabolic capabilities of these communties. Metagenomic data from similar serpentine environments [1] have identified Betaproteobacteria belonging to the order Burkholderiales and Gram-positive bacteria from the order Clostridiales as key components of the serpentine microbiome. In an effort to better characterize the microbial community, metabolism, and geochemistry at CROMO, fluids from two representative wells (N08B and CSWold) were sampled during recent field campaigns. Geochemical characterization of the fluids includes measurements of dissolved gases (H2, CO, CH4), dissolved inorganic and organic carbon, volatile fatty acids, and nutrients. The wells selected can be differentiated in that N08B had higher pH (10-11), lower dissolved oxygen, and cell counts ranging from 105-106 cells mL-1 of fluid, with an abundance of the betaproteobacterium Hydrogenophaga. In contrast, fluids from CSWold have slightly lower pH (9-9.5), DO, and conductivity, as well as higher TDN and TDP. CSWold fluid is also characterized for having lower cell counts (~103 cells mL-1) and an abundance of Dethiobacter, a taxon within the phylum Clostridiales. Microcosm experiments were conducted with the purpose of monitoring carbon fixation, methanotrophy and metabolism of small organic compounds, such as acetate and formate, while tracing changes in fluid

  6. Rumen microbial (meta)genomics and its application to ruminant production.

    Science.gov (United States)

    Morgavi, D P; Kelly, W J; Janssen, P H; Attwood, G T

    2013-03-01

    Meat and milk produced by ruminants are important agricultural products and are major sources of protein for humans. Ruminant production is of considerable economic value and underpins food security in many regions of the world. However, the sector faces major challenges because of diminishing natural resources and ensuing increases in production costs, and also because of the increased awareness of the environmental impact of farming ruminants. The digestion of feed and the production of enteric methane are key functions that could be manipulated by having a thorough understanding of the rumen microbiome. Advances in DNA sequencing technologies and bioinformatics are transforming our understanding of complex microbial ecosystems, including the gastrointestinal tract of mammals. The application of these techniques to the rumen ecosystem has allowed the study of the microbial diversity under different dietary and production conditions. Furthermore, the sequencing of genomes from several cultured rumen bacterial and archaeal species is providing detailed information about their physiology. More recently, metagenomics, mainly aimed at understanding the enzymatic machinery involved in the degradation of plant structural polysaccharides, is starting to produce new insights by allowing access to the total community and sidestepping the limitations imposed by cultivation. These advances highlight the promise of these approaches for characterising the rumen microbial community structure and linking this with the functions of the rumen microbiota. Initial results using high-throughput culture-independent technologies have also shown that the rumen microbiome is far more complex and diverse than the human caecum. Therefore, cataloguing its genes will require a considerable sequencing and bioinformatic effort. Nevertheless, the construction of a rumen microbial gene catalogue through metagenomics and genomic sequencing of key populations is an attainable goal. A rumen

  7. Hemodialysis access procedures

    Science.gov (United States)

    Kidney failure - chronic-dialysis access; Renal failure - chronic-dialysis access; Chronic renal insufficiency-dialysis access; Chronic kidney failure-dialysis access; Chronic renal failure-dialysis access

  8. Priorities for microbial biodiversity research: Summary and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    Microbial diversity is an unseen national as well as international resource that deserves greater attention. Too small to be seen no longer means too small to be studied or values. Microbial diversity encompasses the spectrum of microscopic organisms including bacteria, fungi, algae and protozoa. These organisms populate the soil, water and air that surround us and live in more unusual environments such as the boiling water of hydrothermal vents, deep ocean trenches and alkali lakes. This report summarizes a workshop on microbial biodiversity which was organized by the Center for Microbial Ecology at Michigan State University.

  9. Access to Local Agriculture and Weight Outcomes

    OpenAIRE

    Berning, Joshua P.

    2012-01-01

    Recent studies examine the impact of the built environment on health outcomes such as obesity. Several studies find for certain populations that access to unhealthy food has a positive effect on obesity, whereas access to healthy choices has a negative effect. Given the growth and popularity of locally grown food, we examine how individual weight outcomes are affected by access to direct-to-consumer local food. After controlling for potential endogeneity, we find that greater access to local ...

  10. Microbial Profiling Of Cyanobacteria From VIT Lake

    Directory of Open Access Journals (Sweden)

    Swati Singh

    2015-08-01

    Full Text Available The application of molecular biological methods to study the diversity and ecology of micro-organisms in natural environments has been practice in mid-1980. The aim of our research is to access the diversity composition and functioning of complex microbial community found in VIT Lake. Molecular ecology is a new field in which microbes can be recognized and their function can be understood at the DNA or RNA level which is useful for constructing genetically modified microbes by recombinant DNA technology for reputed use in the environment. In this research first we will isolate cyanobacteria in lab using conventional methods like broth culture and spread plate method then we will analyze their morphology using various staining methods and DNA and protein composition using electrophoresis method. The applications of community profiling approaches will advance our understanding of the functional role of microbial diversity in VIT Lake controls on microbial community composition.

  11. A new access scheme in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    GU Xue-lin; YAN Wei; TIAN Hui; ZHANG Ping

    2006-01-01

    This article presents a dynamic random access scheme for orthogonal frequency division multiple access (OFDMA) systems. The key features of the proposed scheme are:it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes,and it can adjust the number of random access channels in a media access control (MAC) frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.

  12. Microbial Diversity of Impact-Generated Habitats

    Science.gov (United States)

    Pontefract, Alexandra; Osinski, Gordon R.; Cockell, Charles S.; Southam, Gordon; McCausland, Phil J. A.; Umoh, Joseph; Holdsworth, David W.

    2016-10-01

    Impact-generated lithologies have recently been identified as viable and important microbial habitats, especially within cold and arid regions such as the polar deserts on Earth. These unique habitats provide protection from environmental stressors, such as freeze-thaw events, desiccation, and UV radiation, and act to trap aerially deposited detritus within the fissures and pore spaces, providing necessary nutrients for endoliths. This study provides the first culture-independent analysis of the microbial community structure within impact-generated lithologies in a Mars analog environment, involving the analysis of 44,534 16S rRNA sequences from an assemblage of 21 rock samples that comprises three shock metamorphism categories. We find that species diversity increases (H = 2.4-4.6) with exposure to higher shock pressures, which leads to the development of three distinct populations. In each population, Actinobacteria were the most abundant (41%, 65%, and 59%), and the dominant phototrophic taxa came from the Chloroflexi. Calculated porosity (a function of shock metamorphism) for these samples correlates (R2 = 0.62) with inverse Simpson indices, accounting for overlap in populations in the higher shock levels. The results of our study show that microbial diversity is tied to the amount of porosity in the target substrate (as a function of shock metamorphism), resulting in the formation of distinct microbial populations.

  13. Structural insights of microbial community of Deulajhari (India hot spring using 16s-rRNA based metagenomic sequencing

    Directory of Open Access Journals (Sweden)

    Archana Singh

    2016-03-01

    Full Text Available Insights about the distribution of the microbial community prove to be the major goal of understanding microbial ecology which remains to be fully deciphered. Hot springs being hub for the thermophilic microbiota attract the attention of the microbiologists. Deulajhari hot spring cluster is located in the Angul district of Odisha. Covered within a wooded area, Deulajhari hot spring is also fed by the plant litter resulting in a relatively high amount of total organic content (TOC. For the first time, Illumina sequencing based biodiversity analysis of microbial composition is studied through amplicon metagenome sequencing of 16s rRNA targeting V3‐V4 region using metagenomic DNA from the hot spring sediment. Over 28 phyla were detected through the amplicon metagenome sequencing of which the most dominating phyla at the existing physiochemical parameters like; temperature 69 °C, pH 8.09, electroconductivity 0.025 dSm−1 and total organic carbon 0.356%, were Proteobacteria (88.12%, Bacteriodetes (10.76%, Firmicutes (0.35%, Spirochetes (0.18% and chloroflexi (0.11%. Approximately 713 species were observed at the above physiochemical parameters. The analysis of the metagenome provides the quantitative insights into microbial populations based on the sequence data in Deulajhari hot spring. Metagenome sequence is deposited to SRA database which is available at NCBI with accession no. SRX1459736.

  14. Evolution of Microbial Biomasses C and N during the Composting of Municipal solid Wastes

    Directory of Open Access Journals (Sweden)

    Olfa Fourti

    2011-01-01

    Full Text Available Problem statement: The aim of this study was mainly focused on the evolution of microbial biomasses C and N during the composting of municipal solid wastes. Approach: The carbon and the nitrogen of the microbial biomass (BC and BN were studied using the fumigation-extraction method. Results: The dynamics of the BC/BN ratio, index of the chemical composition of the whole microbial population suggested a shift in the composition of microbial populations during the process from prevailing bacteria and actinomycetes to prevailing fungi. Conclusion/Recommendations: Microbial characterization of composting is of importance for the optimization of the process and the quality of the end product.

  15. Microbial astronauts: assembling microbial communities for advanced life support systems

    Science.gov (United States)

    Roberts, M. S.; Garland, J. L.; Mills, A. L.

    2004-01-01

    Extension of human habitation into space requires that humans carry with them many of the microorganisms with which they coexist on Earth. The ubiquity of microorganisms in close association with all living things and biogeochemical processes on Earth predicates that they must also play a critical role in maintaining the viability of human life in space. Even though bacterial populations exist as locally adapted ecotypes, the abundance of individuals in microbial species is so large that dispersal is unlikely to be limited by geographical barriers on Earth (i.e., for most environments "everything is everywhere" given enough time). This will not be true for microbial communities in space where local species richness will be relatively low because of sterilization protocols prior to launch and physical barriers between Earth and spacecraft after launch. Although community diversity will be sufficient to sustain ecosystem function at the onset, richness and evenness may decline over time such that biological systems either lose functional potential (e.g., bioreactors may fail to reduce BOD or nitrogen load) or become susceptible to invasion by human-associated microorganisms (pathogens) over time. Research at the John F. Kennedy Space Center has evaluated fundamental properties of microbial diversity and community assembly in prototype bioregenerative systems for NASA Advanced Life Support. Successional trends related to increased niche specialization, including an apparent increase in the proportion of nonculturable types of organisms, have been consistently observed. In addition, the stability of the microbial communities, as defined by their resistance to invasion by human-associated microorganisms, has been correlated to their diversity. Overall, these results reflect the significant challenges ahead for the assembly of stable, functional communities using gnotobiotic approaches, and the need to better define the basic biological principles that define ecosystem

  16. Microbial astronauts: assembling microbial communities for advanced life support systems.

    Science.gov (United States)

    Roberts, M S; Garland, J L; Mills, A L

    2004-02-01

    Extension of human habitation into space requires that humans carry with them many of the microorganisms with which they coexist on Earth. The ubiquity of microorganisms in close association with all living things and biogeochemical processes on Earth predicates that they must also play a critical role in maintaining the viability of human life in space. Even though bacterial populations exist as locally adapted ecotypes, the abundance of individuals in microbial species is so large that dispersal is unlikely to be limited by geographical barriers on Earth (i.e., for most environments "everything is everywhere" given enough time). This will not be true for microbial communities in space where local species richness will be relatively low because of sterilization protocols prior to launch and physical barriers between Earth and spacecraft after launch. Although community diversity will be sufficient to sustain ecosystem function at the onset, richness and evenness may decline over time such that biological systems either lose functional potential (e.g., bioreactors may fail to reduce BOD or nitrogen load) or become susceptible to invasion by human-associated microorganisms (pathogens) over time. Research at the John F. Kennedy Space Center has evaluated fundamental properties of microbial diversity and community assembly in prototype bioregenerative systems for NASA Advanced Life Support. Successional trends related to increased niche specialization, including an apparent increase in the proportion of nonculturable types of organisms, have been consistently observed. In addition, the stability of the microbial communities, as defined by their resistance to invasion by human-associated microorganisms, has been correlated to their diversity. Overall, these results reflect the significant challenges ahead for the assembly of stable, functional communities using gnotobiotic approaches, and the need to better define the basic biological principles that define ecosystem

  17. Microbial fuel cells

    International Nuclear Information System (INIS)

    Microbial fuel cells (MFC) are a promising technology for sustainable production of alternative energy and waste treatment. A microbial fuel cell transformation chemical energy in the chemical bonds in organic compounds to electrical energy through catalytic reactions of microorganisms under anaerobic conditions. It has been known for many years that it is possible to generate electricity directly by using bacteria to break down organic substrates. Key words: microbial fuel cells (MFC), biosensor, wastewater treatment

  18. Microbial Changes during Pregnancy, Birth, and Infancy.

    Science.gov (United States)

    Nuriel-Ohayon, Meital; Neuman, Hadar; Koren, Omry

    2016-01-01

    Several healthy developmental processes such as pregnancy, fetal development, and infant development include a multitude of physiological changes: weight gain, hormonal, and metabolic changes, as well as immune changes. In this review, we present an additional important factor which both influences and is affected by these physiological processes-the microbiome. We summarize the known changes in microbiota composition at a variety of body sites including gut, vagina, oral cavity, and placenta, throughout pregnancy, fetal development, and early childhood. There is still a lot to be discovered; yet several pieces of research point to the healthy desired microbial changes. Future research is likely to unravel precise roles and mechanisms of the microbiota in gestation; perhaps linking the metabolic, hormonal, and immune changes together. Although some research has started to link microbial dysbiosis and specific microbial populations with unhealthy pregnancy complications, it is important to first understand the context of the natural healthy microbial changes occurring. Until recently the placenta and developing fetus were considered to be germ free, containing no apparent microbiome. We present multiple study results showing distinct microbiota compositions in the placenta and meconium, alluding to early microbial colonization. These results may change dogmas and our overall understanding of the importance and roles of microbiota from the beginning of life. We further review the main factors shaping the infant microbiome-modes of delivery, feeding, weaning, and exposure to antibiotics. Taken together, we are starting to build a broader understanding of healthy vs. abnormal microbial alterations throughout major developmental time-points. PMID:27471494

  19. The electric picnic: synergistic requirements for exoelectrogenic microbial communities

    KAUST Repository

    Kiely, Patrick D

    2011-06-01

    Characterization of the various microbial populations present in exoelectrogenic biofilms provides insight into the processes required to convert complex organic matter in wastewater streams into electrical current in bioelectrochemical systems (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 end products by exoelectrogens (typically Geobacter species) relieves feedback inhibition for the fermentative consortia, allowing for rapid metabolism of organics. Identification of specific syntrophic processes and the communities characteristic of these anodic biofilms will be a valuable aid in improving the performance of BESs. © 2011 Elsevier Ltd.

  20. Effect of rhizosphere on soil microbial community and in-situ pyrene biodegradation

    Science.gov (United States)

    Su, Y.; Yang, X.; Chiou, C.T.

    2008-01-01

    To access the influence of a vegetation on soil microorganisms toward organic pollutant biogegration, this study examined the rhizospheric effects of four plant species (sudan grass, white clover, alfalfa, and fescue) on the soil microbial community and in-situ pyrene (PYR) biodegradation. The results indicated that the spiked PYR levels in soils decreased substantially compared to the control soil without planting. With equal planted densities, the efficiencies of PYR degradation in rhizosphere with sudan grass, white clover, alfalfa and fescue were 34.0%, 28.4%, 27.7%, and 9.9%, respectively. However, on the basis of equal root biomass the efficiencies were in order of white clover >> alfalfa > sudan > fescue. The increased PYR biodegradation was attributed to the enhanced bacterial population and activity induced by plant roots in the rhizosphere. Soil microbial species and biomasses were elucidated in terms of microbial phospholipid ester-linked fatty acid (PLFA) biomarkers. The principal component analysis (PCA) revealed significant changes in PLFA pattern in planted and non-planted soils spiked with PYR. Total PLFAs in planted soils were all higher than those in non-planted soils. PLFA assemblages indicated that bacteria were the primary PYR degrading microorganisms, and that Gram-positive bacteria exhibited higher tolerance to PYR than Gram-negative bacteria did. ?? 2008 Higher Education Press and Springer-Verlag GmbH.

  1. Effect of rhizosphere on soil microbial community and in-situ pyrene biodegradation

    Institute of Scientific and Technical Information of China (English)

    Yuhong SU; Xueyun YANG; Cary T CHIOU

    2008-01-01

    To access the influence of a vegetation on soil microorganisms toward organic pollutant biogegration, this study examined the rhizospheric effects of four plant species (sudan grass, white clover, alfalfa, and rescue) on the soil microbial community and in-situ pyrene (PYR) bio-degradation. The results indicated that the spiked PYR levels in soils decreased substantially compared to the con-trol soil without planting. With equal planted densities, the efficiencies of PYR degradation in rhizosphere with sudan grass, white clover, alfalfa and fescue were 34.0%, 28.4%, 27.7%, and 9.9%, respectively. However, on the basis of equal root biomass the efficiencies were in order of white clover >> alfalfa > sudan > rescue, The increased PYR biodegradation was attributed to the enhanced bacterial population and activity induced by plant roots in the rhizo-sphere. Soil microbial species and biomasses were eluci-dated in terms of microbial phospholipid ester-linked fatty acid (PLFA) biomarkers. The principal component analysis (PCA) revealed significant changes in PLFA pat-tern in planted and non-planted soils spiked with PYR. Total PLFAs in planted soils were all higher than those in non-planted soils. PLFA assemblages indicated that bac-teria were the primary PYR degrading microorganisms, and that Gram-positive bacteria exhibited higher tolerance to PYR than Gram-negative bacteria did.

  2. Efficacy of living preparation of lactobacillus in regulating disturbance of vaginal microbial population in women after delivery%乳杆菌活菌胶囊调整产后阴道菌群失衡的效果

    Institute of Scientific and Technical Information of China (English)

    张晓洁; 张美娟; 葛高霞; 王敏; 董宁

    2012-01-01

    To investigate the efficacy of living preparation of lactobacillus in regulating disturbance of vaginal microbial population in women after delivery. Methods A total of 600 post-partum women at 6 to 8 weeks underwent bacterial vaginosis(BV) screening with Amsel standard. Post-partum BV was diagnosed in 356 cases (174 breast-feeding women and 182 without breast-feeding), who were equally divided into two groups of A (treated with living preparation of lactobacillus) and B(treated with compound metronidazole suppository). The treatment lasted for 10 days and examination was repeaded 7 days later. Another 600 women of childbearing age were taken as the controls (group CX Results The incidence rate of BV in 6 to 8 weeks post-partum women was 59. 33%(356/600), which was significantly higher than 19, 33% (116/600) in group C(F<0.05). The total effectiveness rate of group A was similar to that of group B (92, 70% vs. 92-13%). Conclusion The post-partum women in 6 to 8 weeks after delivery has a higher incidence of BV, Living preparation of lactobacillus can effectively improve the ecological environment of the vagina.%目的 观察乳杆菌活菌胶囊治疗产后细菌性阴道病(BV)的有效性.方法 按Amsel 标准对600例产后6-8周妇女进行BV筛查,将确诊BV的356例产妇(哺乳妇女174例,未哺乳妇女182例)随机分为两组:A组178例,采用定君生胶囊阴道给药治疗;B组178例,采用复方甲硝唑栓阴道给药治疗.均连续用药10d,停药7d后复查.选600名正常育龄妇女为对照组.结果 产后6-8周妇女BV检出率为59.33%(356/600),明显高于对照组的19.33%(116/600)(P<0.05).A 组治疗BV的总有效率为92.70%,B组为92.13%(P>0.05).结论 产后6-8周妇女BV发病率较高,乳杆菌活菌胶囊能有效改善阴道内生态环境,安全、有效,易为产妇所接受.

  3. 不同底物对海洋混合菌群产氢的影响%Effects of Different Substrates on Hydrogen Production of Mixed Microbial Population from Marine

    Institute of Scientific and Technical Information of China (English)

    刘洪艳

    2011-01-01

    将采自天津潮间带的污泥进行热休克处理,厌氧条件下富集混合菌群进行产氢试验.混合菌群分别接种于含葡萄糖、蔗糖、乳糖、淀粉和蛋白胨的培养液中,测定不同底物培养条件下混合菌群产氢量及菌群组成.结果表明,以蔗糖为底物时,混合菌群产氢量最高,为(787±24) mL/L;混合菌群以葡糖糖、乳糖和淀粉为底物时,产氢量依次为(530±20)、(46±5)和(455±35) mL/L;混合菌群不能利用蛋白胨为底物产氢.变性梯度凝胶电泳( DGGE)分析不同底物培养条件下的产氢混合菌群组成.混合菌群16S rRNA基因的DGGE分离结果表明,在蛋白胨培养条件下,混合菌群没有能够形成优势菌,其他底物培养时,混合菌群的优势菌是Clostridium sp..%Sludge collected from the intertidal zone beach in Tianjin, was treated with heat shock and the enriched mixed microbial population (MMP) was carried out hydrogen production experiment in anaerobic condition. The MMP was respectively inoculated in liquid media of glucose, sucrose, lactose, starch, and peptone to determine the effects under the conditions of different substrates on hydrogen production and the constituents of the MMP. The results showed that when using sucrose as substrate it produced hydrogen at (787 ±24) mL/L, the highest amount among the five substrates. When using glucose, lactose, and starch as substrates, the MMP produced (530 ±20) mL/L, (46 ± S) mL/L, and (455 ±35) mL/L of hydrogen respectively, however, the MMP could not utilized peptone as a substrate to produce hydrogen. The composition the MMP producing hydrogen under culture conditions in different substrates was analyzed by denaturing gradient gel electrophoresis (DGGE). The DCCE isolation result of 16S rRNA gene of the MMP showed that there were no dominant strains in it when cultured with peptone. When cultured with other substrates the dominant strain of the MMP was Closlridium sp.

  4. Understanding differences in access and use of healthcare between international immigrants to Chile and the Chilean-born: a repeated cross-sectional population-based study in Chile

    Directory of Open Access Journals (Sweden)

    Cabieses Baltica

    2012-11-01

    Full Text Available Abstract Introduction International evidence indicates consistently lower rates of access and use of healthcare by international immigrants. Factors associated with this phenomenon vary significantly depending on the context. Some research into the health of immigrants has been conducted in Latin America, mostly from a qualitative perspective. This population-based study is the first quantitative study to explore healthcare provision entitlement and use of healthcare services by immigrants in Chile and compare them to the Chilean-born. Methods Data come from the nationally representative CASEN (Socioeconomic characterization of the population in Chile surveys, conducted in 2006 and 2009. Self-reported immigrants were compared to the Chilean-born, by demographic characteristics (age, sex, urban/rural, household composition, ethnicity, socioeconomic status (SES: education, household income, contractual status, healthcare provision entitlement (public, private, other, none, and use of primary services. Weighted descriptive, stratified and adjusted regression models were used to analyse factors associated with access to and use of healthcare. Results There was an increase in self-reported immigrant status and in household income inequality among immigrants between 2006 and 2009. Over time there was a decrease in the rate of immigrants reporting no healthcare provision and an increase in reporting of private healthcare provision entitlement. Compared to the Chilean-born, immigrants reported higher rates of use of antenatal and gynaecological care, lower use of well-baby care, and no difference in the use of Pap smears or the number of attentions received in the last three months. Immigrants in the bottom income quintile were four times more likely to report no healthcare provision than their equivalent Chilean-born group (with different health needs, i.e. vertical inequity. Disabled immigrants were more likely to have no healthcare provision compared

  5. Understanding differences in access and use of healthcare between international immigrants to Chile and the Chilean-born: a repeated cross-sectional population-based study in Chile

    Science.gov (United States)

    2012-01-01

    Introduction International evidence indicates consistently lower rates of access and use of healthcare by international immigrants. Factors associated with this phenomenon vary significantly depending on the context. Some research into the health of immigrants has been conducted in Latin America, mostly from a qualitative perspective. This population-based study is the first quantitative study to explore healthcare provision entitlement and use of healthcare services by immigrants in Chile and compare them to the Chilean-born. Methods Data come from the nationally representative CASEN (Socioeconomic characterization of the population in Chile) surveys, conducted in 2006 and 2009. Self-reported immigrants were compared to the Chilean-born, by demographic characteristics (age, sex, urban/rural, household composition, ethnicity), socioeconomic status (SES: education, household income, contractual status), healthcare provision entitlement (public, private, other, none), and use of primary services. Weighted descriptive, stratified and adjusted regression models were used to analyse factors associated with access to and use of healthcare. Results There was an increase in self-reported immigrant status and in household income inequality among immigrants between 2006 and 2009. Over time there was a decrease in the rate of immigrants reporting no healthcare provision and an increase in reporting of private healthcare provision entitlement. Compared to the Chilean-born, immigrants reported higher rates of use of antenatal and gynaecological care, lower use of well-baby care, and no difference in the use of Pap smears or the number of attentions received in the last three months. Immigrants in the bottom income quintile were four times more likely to report no healthcare provision than their equivalent Chilean-born group (with different health needs, i.e. vertical inequity). Disabled immigrants were more likely to have no healthcare provision compared to the disabled Chilean

  6. MICROBIAL FUEL CELL

    DEFF Research Database (Denmark)

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  7. Biofilms: A microbial home

    OpenAIRE

    Chandki, Rita; Banthia, Priyank; Banthia, Ruchi

    2011-01-01

    Microbial biofilms are mainly implicated in etiopathogenesis of caries and periodontal disease. Owing to its properties, these pose great challenges. Continuous and regular disruption of these biofilms is imperative for prevention and management of oral diseases. This essay provides a detailed insight into properties, mechanisms of etiopathogenesis, detection and removal of these microbial biofilms.

  8. Critical parameters influencing microbial corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Ferris, F.G.

    1991-03-31

    The effects of injection water chemistry on the development of corrosive microbial biofilms, corrosion rates, and deposition of corrosion deposits was studied at an oil field water injection test facility in Alberta. Data were collected during two separate 12 week duration experimental runs. Attached bacterial populations were allowed to develop on removable steel sample coupons, and chemical treatment started after four weeks. Two different cocodiamine and bromonitropropane-diol based biocides were used in addition to a phosphate scale inhibitor. Of the various constituents present in the injection water, sulfate was noted as having a strong stimulative effect on sulfate reducing bacteria (SRB). Nitrate was inhibitory, whereas sulfide exhibited a positive correlation with SRB. While high concentrations of magnesium constrained SRB and organic acid producing bacteria (APB), high bacterial counts coincided with an apparent optimal range of 15 to 20 ppM total organic carbon. The results indicated that injection water chemistry strongly influences microbial growth and population distribution in water injection systems. Scanning electron microscopy indicated that complex pore geometries contribute to the meager permeability that constrains the penetration of biocides into biofilms. Most of the iron sulfide corrosion deposits consisted of an amorphous sulfur-deficient chlorine-rich phase, which sustains high corrosion rates when depolarized by hydrogen consuming SRB. 33 refs., 54 figs., 3 tabs.

  9. Las barreras de acceso a los servicios de salud en la población indígena de Rabinal en Guatemala Barriers to accessing health care services for the indigenous population in Rabinal, Guatemala

    Directory of Open Access Journals (Sweden)

    Maeve Hautecoeur

    2007-04-01

    Full Text Available OBJETIVO: Identificar y documentar las barreras de acceso a los servicios de salud en la población indígena de Rabinal en Guatemala. MATERIAL Y MÉTODOS: Se privilegió el análisis cualitativo y la recopilación de datos se realizó en Rabinal durante dos meses (Guatemala. Se realizaron quince entrevistas semi dirigidas a indígenas achís y cinco entrevistas a profesionales de la salud. Un grupo de discusión fue formado para validar la información recogida durante las entrevistas individuales; la retranscripción de éstas y la compilación de los datos permitieron hacer el análisis de contenido. RESULTADOS: Las barreras de acceso están interrelacionadas y las barreras geográficas están relacionadas con la distancia y con la escasez de transporte; las barreras económicas son los precios de las consultas y de los medicamentos, además, entre las barreras culturales, la lengua española es un obstáculo. Los indígenas tienen otra concepción de la medicina y de los tratamientos y se quejan en ocasiones de trato abusivo por parte de los profesionales sanitarios. A su vez, los profesionales de la salud reconocen que el trauma de la guerra está presente y critican las malas condiciones de vida y la falta de recursos. CONCLUSIONES: Los servicios de salud no son adecuados ni suficientes para responder a las necesidades de la población local.OBJECTIVE: To identify and document access barriers to health care services for the indigenous population in Rabinal, Guatemala. MATERIAL AND METHODS: A qualitative analysis was used. Over a period of two months, 20 semi-directional interviews were conducted in Rabinal, Guatemala: 15 with Achis indigenous people and five with health professionals. A focus group was done to verify the information collected during the individual interviews. The qualitative analysis was based on the transcription of interviews and the compilation of the data. RESULTS: Barriers to access are inter-relational. Geographic

  10. 丁草胺污染对高产水稻土微生物区系的影响%Effects of butachlor-contamination on population of microbial communities in high-yield paddy soils

    Institute of Scientific and Technical Information of China (English)

    张仕颖; 夏运生; 肖炜; 崔晓龙; 王永霞; 史静; 张乃明

    2014-01-01

    处理抑制作用微弱,中、高浓度处理磷酸盐溶解菌数量则始终显著低于CK,表现为丁草胺浓度越高,抑制作用越明显;低浓度丁草胺对硅酸盐细菌数量影响不明显,中、高浓度则对其有抑制作用,B150在施药7和15 d时分别比CK低60.7%和58.1%,表现为浓度越高抑制作用越明显。%Soil microorganism is the most potential indicator of soil quality evaluation, and is closely related to the stability and productivity of agricultural ecosystem. Taoyuan, Yunnan province is a special eco-site which keeps the highest yield records of rice cultivation in small planting areas, and butachlor is applied at the pre-emergence stage of rice year in and year out in Taoyuan. Therefore, it is significant to understand the ecological effects of the herbicide butachlor on microbial communities in high-yield paddy soils. Effects of butachlor-contamination on population of aerobic bacteria, actinobacteria, fungi, nitrogen fixing bacteria、phosphate solubilizing bacteria and silicate dissolving bacteria in high-yield paddy soils were investigated under laboratory conditions, and the microbial communities structures under different butachlor concentrations (calculated by active ingredient 0.15, 0.30 and 1.5 mg·kg-1) were evaluated using plate count. The results showed that the number of aerobic bacteria were higher than CK 78.6% and 153.8% after application of butachlor at high or middle concentrations (0.30 and 1.50 mg/kg dried soil) 7d later, and then declined significantly, while the number did not change significantly at low butachlor concentration (0.15 mg·kg-1 dried soil). The number of actinomycetes was higher than CK 75.1% after application of butachlor at high concentrations 7 d later, and 125.0% at middle concentrations 15 d later, butachlor at high or middle concentrations accelerated the growth of actinomycetes, while showed an inhibition at low concentration. The proliferation and growth of fungi

  11. Turning Russian specialized microbial culture collections into resource centers for biotechnology.

    Science.gov (United States)

    Ivshina, Irena B; Kuyukina, Maria S

    2013-11-01

    Specialized nonmedical microbial culture collections contain unique bioresources that could be useful for biotechnology companies. Cooperation between collections and companies has suffered from shortcomings in infrastructure and legislation, hindering access to holdings. These challenges may be overcome by the transformation of collections into national bioresource centers and integration into international microbial resource networks.

  12. Regional microbial signatures positively correlate with differential wine phenotypes: evidence for a microbial aspect to terroir.

    Science.gov (United States)

    Knight, Sarah; Klaere, Steffen; Fedrizzi, Bruno; Goddard, Matthew R

    2015-01-01

    Many crops display differential geographic phenotypes and sensorial signatures, encapsulated by the concept of terroir. The drivers behind these differences remain elusive, and the potential contribution of microbes has been ignored until recently. Significant genetic differentiation between microbial communities and populations from different geographic locations has been demonstrated, but crucially it has not been shown whether this correlates with differential agricultural phenotypes or not. Using wine as a model system, we utilize the regionally genetically differentiated population of Saccharomyces cerevisiae in New Zealand and objectively demonstrate that these populations differentially affect wine phenotype, which is driven by a complex mix of chemicals. These findings reveal the importance of microbial populations for the regional identity of wine, and potentially extend to other important agricultural commodities. Moreover, this suggests that long-term implementation of methods maintaining differential biodiversity may have tangible economic imperatives as well as being desirable in terms of employing agricultural practices that increase responsible environmental stewardship. PMID:26400688

  13. IMPROVING ACCESS TO DRUGS

    Directory of Open Access Journals (Sweden)

    Max Joseph Herman

    2012-11-01

    Full Text Available Although essentially not all therapies need drug intervention, drugs is still an important components in health sector, either in preventive, curative, rehabilitative or promotion efforts. Hence the access to drugs is a main problem, either in international or national scale even to the smallest unit. The problem on access to drugs is very complicated and cannot be separated especially from pharmacy management problems; moreover in general from the overall lack of policy development and effective of health policy, and also the implementation process. With the policy development and effective health policy, rational drug uses, sufficient health service budget so a country can overcome the health problems. Besides infrastructures, regulations, distribution and cultural influences; the main obstacles for drug access is drugs affordability if the price of drugs is an important part and determined by many factors, especially the drug status whether is still patent orgenerics that significantly decrease cost of health cares and enhance the drugs affordability. The determination of essential drug prices in developing countries should based on equity principal so that poor people pay cheaper and could afford the essential drugs. WHO predicts two third of world population can not afford the essential drugs in which in developing countries, some are because of in efficient budget allocation in consequence of drug distribution management, including incorrect selection and allocation and also irrational uses. In part these could be overcome by enhancing performances on the allocation pharmacy needs, including the management of information system, inventory management, stock management and the distribution. Key words: access, drugs, essential drugs, generic drugs

  14. Sediment Interfaces: Ecotones on a Microbial Scale

    Science.gov (United States)

    Borchers, M. R.; Colwell, F. S.; D'Angelo, G.; Thurber, A. R.; Graw, M. F.

    2015-12-01

    Ecotones - transitions between different biomes - often support greater faunal diversity than the adjacent ecological systems. For subseafloor microorganisms, defined geological and chemical gradients have been shown to affect population sizes and community structure, but the role that sediment interfaces play is still unclear. Here, we test the hypothesis that zones of transition between two distinct sediment types increase microbial diversity and change community composition. Concurrently, we explore those factors that drive deep-subsurface microbial community structure (e.g., depth, interstitial water chemistry, methane concentrations, clay content). Samples from IODP Expedition 349 - South China Sea Tectonics - had interfaces of either ash/clay or turbidite/clay boundaries sampled , DNA extracted, and the 16S rRNA gene analyzed on an Illumina MiSeq platform. Initial analyses reveal that microbial communities in sediment samples are distinct from communities in drilling fluid, indicating that contamination is unlikely. In four of the eight complete interfaces currently analyzed we found an increase in diversity (based on the chao1 index), in certain cases doubling the diversity of the adjacent rock types. The pattern was not uniform across all interfaces. While some posit that ecotones provide a mixing of the two adjacent communities, we were surprised to find an abundance (mean = 392 OTUs) of unique microbial taxa within the ecotone itself when compared to adjacent sediment (mean=282 unique OTUs). Thus while diversity was not uniformly increased in ecotones, the interface led to divergent microbial communities that were not simply mixtures of those adjacent. We will discuss the ability of abiotic factors in explaining the among ecotone variance that we observed. Our investigation helps to characterize the factors that drive microbial community structure of the subseafloor while highlighting the need to focus on habitat heterogeneity at a scale pertinent to

  15. Microbial activity in soils following steam treatment.

    Science.gov (United States)

    Richardson, Ruth E; James, C Andrew; Bhupathiraju, Vishvesh K; Alvarez-Cohen, Lisa

    2002-01-01

    Steam enhanced extraction (SEE) is an aquifer remediation technique that can be effective at removing the bulk of non-aqueous phase liquid (NAPL) contamination from the subsurface, particularly highly volatile contaminants. However, low volatility compounds such as polynuclear aromatic hydrocarbons (PAHs) are less efficiently removed by this process. This research evaluated the effects of steam injection on soil microbial activity, community structure, and the potential for biodegradation of contaminants following steam treatment. Three different soils were evaluated: a laboratory-prepared microbially-enriched soil, soil from a creosote contaminated field site, and soil from a chlorinated solvent and waste oil contaminated field site. Results from field-scale steaming are also presented. Microbial activity before and after steam treatment was evaluated using direct epifluorescent microscopy (DEM) using the respiratory activity dye 5-cyano-2,3, ditolyl tetrazolium chloride (CTC) in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF) to yield a quantitative assessment of active and total microbial numbers. DEM results indicate that steamed soils that were analyzed while still hot exhibited microbial activity levels that were below detection. However, soil samples that were slowly cooled, more closely reflecting the conditions of applied SEE, exhibited microbial activity levels that were comparable to presteamed soils. Samples from a field-site where steam was applied continuously for 6 weeks also showed high levels of microbial activity following cooling. The metabolic capabilities of the steamed communities were investigated by measuring cell growth in enrichment cultures on various substrates. These studies provided evidence that organisms capable of biodegradation were among the mesophilic populations that survived steam treatment. Fluorescent in situ hybridization (FISH) analysis of the soils with domain-level rRNA probes suggest

  16. Regional microbial signatures positively correlate with differential wine phenotypes: evidence for a microbial aspect to terroir

    OpenAIRE

    Sarah Knight; Steffen Klaere; Bruno Fedrizzi; Goddard, Matthew R.

    2015-01-01

    Many crops display differential geographic phenotypes and sensorial signatures, encapsulated by the concept of terroir. The drivers behind these differences remain elusive, and the potential contribution of microbes has been ignored until recently. Significant genetic differentiation between microbial communities and populations from different geographic locations has been demonstrated, but crucially it has not been shown whether this correlates with differential agricultural phenotypes or no...

  17. Expansion of Microbial Forensics.

    Science.gov (United States)

    Schmedes, Sarah E; Sajantila, Antti; Budowle, Bruce

    2016-08-01

    Microbial forensics has been defined as the discipline of applying scientific methods to the analysis of evidence related to bioterrorism, biocrimes, hoaxes, or the accidental release of a biological agent or toxin for attribution purposes. Over the past 15 years, technology, particularly massively parallel sequencing, and bioinformatics advances now allow the characterization of microorganisms for a variety of human forensic applications, such as human identification, body fluid characterization, postmortem interval estimation, and biocrimes involving tracking of infectious agents. Thus, microbial forensics should be more broadly described as the discipline of applying scientific methods to the analysis of microbial evidence in criminal and civil cases for investigative purposes. PMID:26912746

  18. Population Dynamics of Bacterial Persistence

    OpenAIRE

    Patra, Pintu; Klumpp, Stefan

    2013-01-01

    Persistence is a prime example of phenotypic heterogeneity, where a microbial population splits into two distinct subpopulations with different growth and survival properties as a result of reversible phenotype switching. Specifically, persister cells grow more slowly than normal cells under unstressed growth conditions, but survive longer under stress conditions such as the treatment with bactericidal antibiotics. We analyze the population dynamics of such a population for several typical ex...

  19. Microbial Inoculants and Their Impact on Soil Microbial Communities: A Review

    Directory of Open Access Journals (Sweden)

    Darine Trabelsi

    2013-01-01

    Full Text Available The knowledge of the survival of inoculated fungal and bacterial strains in field and the effects of their release on the indigenous microbial communities has been of great interest since the practical use of selected natural or genetically modified microorganisms has been developed. Soil inoculation or seed bacterization may lead to changes in the structure of the indigenous microbial communities, which is important with regard to the safety of introduction of microbes into the environment. Many reports indicate that application of microbial inoculants can influence, at least temporarily, the resident microbial communities. However, the major concern remains regarding how the impact on taxonomic groups can be related to effects on functional capabilities of the soil microbial communities. These changes could be the result of direct effects resulting from trophic competitions and antagonistic/synergic interactions with the resident microbial populations, or indirect effects mediated by enhanced root growth and exudation. Combination of inoculants will not necessarily produce an additive or synergic effect, but rather a competitive process. The extent of the inoculation impact on the subsequent crops in relation to the buffering capacity of the plant-soil-biota is still not well documented and should be the focus of future research.

  20. Managing microbial communities for sequentially reconstruct genomes from complex metagenomes

    Science.gov (United States)

    Delmont, Tom O.; Vogel, Timothy M.; Simonet, Pascal

    2013-04-01

    Global understanding on environmental microbial communities is currently limited by the bottleneck of genome reconstruction. Soil is a typical example where individual cells are currently mostly uncultured and metagenomic datasets unassembled. In this study, the microbial community composition of a natural grassland soil was managed under several controlled selective pressures to experiment a "multi-evenness" stratagem for sequentially attempt to reconstruct genomes from a complex metagenome. While lowly represented in the natural community, several newly dominant genomes (an enrichment attaining 105 in some cases) were successfully reconstructed under various "harsh" tested conditions. These genomes belong to several genera including (but not restricted to) Leifsonia, Rhodanobacter, Bacillus, Ktedonobacter, Xanthomonas, Streptomyces and Burkholderia. So far, from 10 to 78% of generated metagenomic datasets were reconstructed, so providing access to more than 88 000 genes of known or unknown functions and to their genetic environment. Adaptative genes directly related to selective pressures were found, mostly in large plasmids. Functions of potential industrial interest (e.g., novel polyketide synthase modules in Streptomyces) were also discovered. Furthermore, an important phage infection snapshot (>1500X of coverage for the most represented phage) was observed among the Streptomyces population (three distinct genomes reconstructed) of a particular enrichment (mercury, 0.02g/kg) during the fourth month of incubation. This "divide and conquer" strategy could be applied to other environments and using auxiliary sequencing approaches like single cell to detect, connect and mine taxa and functions of interest while creating an extensive set of reference genomes from across the planet. Next limit could turn out to become our imagination defining novel selective pressures to sequentially make dominant the 1030 cells of the biosphere.

  1. 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

  2. Microbial Fuel Cells and Microbial Electrolyzers

    Energy Technology Data Exchange (ETDEWEB)

    Borole, Abhijeet P [ORNL

    2015-01-01

    Microbial Fuel Cells and microbial electrolyzers represent an upcoming technology for production of electricity and hydrogen using a hybrid electrocatalytic-biocatalytic approach. The combined catalytic efficiency of these processes has potential to make this technology highly efficient among the various renewable energy production alternatives. This field has attracted electrochemists, biologists and many other disciplines due to its potential to contribute to the energy, water and environment sectors. A brief introduction to the technology is provided followed by current research needs from a bioelectrochemical perspective. Insights into the operation and limitations of these systems achieved via cyclic voltammetry and impedance spectroscopy are discussed along with the power management needs to develop the application aspects. Besides energy production, other potential applications in bioenergy, bioelectronics, chemical production and remediation are also highlighted.

  3. Use of Geographical Information Systems to influence the selection of sampling site locations for the evaluation of microbial diversity

    Science.gov (United States)

    Soil microbial population densities can easily reach one billion cells per gram of soil; and soil microbial diversity has been estimated to reach ten thousand individual species per gram of soil. Soil type and underlying soil structure are considered primary determinants of microbial community struc...

  4. Bioremediation strategies of hydrocarbons and microbial diversity in the Trindade Island shoreline--Brazil.

    Science.gov (United States)

    Rodrigues, Edmo M; Kalks, Karlos H M; Fernandes, Péricles L; Tótola, Marcos R

    2015-12-30

    This study analyzed the microbial diversity colonizing the surface of an oil sample during its contact with water, off the Trindade Island coast and simulated the efficiency of eight different bioremediation strategies for this environment. The diversity analysis was performed using acrylic coupons that served as the support for an oil inclusion at sea. The coupons were sampled over 30 days, and T-RFLP multiplex was employed to access the diversity of fungi, Bacteria and Archaea present on the oil surface. The bioremediation strategies were simulated in a respirometer. The results showed that the bacterial domain was the most dominant in oil colonization and that the richness of the species attached to the oil gradually increases with the exposure time of the coupons. The combination of biostimulation and bioaugmentation with a native population was proven to be an effective strategy for the remediation of oil off the Trindade Island shoreline.

  5. Manipulatiaon of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    Burkhalter, R.; Macnaughton, S.J.; Palmer, R.J.; Smith, C.A.; Whitaker, K.W.; White, D.C.; Zinn, M.; kirkegaard, R.

    1998-08-09

    The Biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms by generated. The most effective monitoring of biofilm formation, succession and desquamation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in the distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  6. Manipulation of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    White, D.C.; Palmer, R.J., Jr.; Zinn, M.; Smith, C.A.; Burkhalter, R.; Macnaughton, S.J.; Whitaker, K.W.; Kirkegaard, R.D.

    1998-08-15

    The biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms be generated. The most effective monitoring of biofilm formation, succession and desaturation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  7. The Microbial Ecology of Dental Caries

    OpenAIRE

    Bowden, G. H. W.

    2011-01-01

    The microbial ecology of caries is complex and incorporates mechanisms common to the natural colonization of the host and to plaque accumulation at sites that do not develop caries lesions. It is not simply accumulation of plaque in the oral cavity but also the ecology of oral bacteria among the host population and the ecology of organisms in the lesion. In these three habitats odontopathogens and other oral bacteria can undergo genotypic change, which may produce phenotypes more virulent or ...

  8. Microbial populations of crude oil spill polluted soils at the Jordan-Iraq desert (the Badia region População microbiana de solos contaminados pelo derramamento de petróleo no deserto Jordão-Iraque (região de Badia

    Directory of Open Access Journals (Sweden)

    Ismail Saadoun

    2008-09-01

    Full Text Available Microbial populations' inhabitants in crude petroleum contaminated soils were analyzed in relation with the soil characteristics. A noticeable greater decline of bacterial counts and diversity but a prevalence of the genus Pseudomonas over the other identified genera in the fresh contaminated soils as compared to the old ones was observed.Analisou-se a população microbiana de solos contaminados pelo derramamento de petróleo em função das características do solo. Uma diminuição notável foi observada nas contagens e diversidade bacterianas, mas observou-se a prevalência de Pseudomonas em relação aos demais gêneros identificados em solos recentemente contaminados, quando comparado com solos com contaminação antiga.

  9. Access For All

    DEFF Research Database (Denmark)

    Andersen, Ove Kjeld; Hjulmand, Christian

    2005-01-01

    Approximately 30% of the Danish population has severe problems in reading everyday text. In the light of the increasing amount of text available on the Internet this poses a democratic challenge to ensure “equal access” to information. The Talking Internet service - Access For All (AFA) - offers...... a free Internet-based tool for reading aloud any marked text with a synthetic voice. The only requirements are a standard equipped PC running a recent Windows OS and an Internet connection. Experiences gathered from running the service for more than 28 months underline the viability of the concept....... There is a clear need for a free internet based Danish text-to-speech synthesizer. Furthermore, the current state of technology i.e. internet bandwidth, response time and server technology is sufficient for setting up an online automatic reading service that is used by steadily growing number of individuals...

  10. Accessibility Long Term Perspectives

    Directory of Open Access Journals (Sweden)

    Kay Axhausen

    2008-11-01

    Full Text Available Improved accessibility and its correlate lower generalized cost of contact, travel and transport have been sought by dynamic human societies for their economic and social benefits through- out recorded history. The paper will reflect about this process at a number of different spatial and temporal scales based on a conceptual model. Looking back at European history, it will trace the interaction between Christaller's logic of local market areas and the idea of (low contact cost network cities. Focusing on Switzerland since 1950 it will show how network investment changed the relative distribution of population and employment and how this interacted with changes in the preferences of the travelers. Using a recent snapshot of how a substantial sample of Swiss maintain their social networks over often very large areas, it will try to answer the question of what will happen in the future, if the current trend of ever lower costs of contact will persist.

  11. IN-VITRO EFFECTS OF HERBICIDES ON SOIL MICROBIAL COMMUNITIES

    Directory of Open Access Journals (Sweden)

    AABID HUSSAIN LONE

    2014-03-01

    Full Text Available Effect of six different herbicides representing four chemical families on soil microbial communities was studied using laboratory microcosm approach. The herbicides tested were isoproturon, metribuzin, clodinafop propargyl, atlantis (Mesosulfuron methyl 3% + Idosulfuron Methyl Sodium 0.6% WG and sulfosulfuron applied at normal agricultural rates, and UPH-110 (Clodinafop propargyl 12% + Metribuzin 42% WG tested at four different application rates. Microbial response to the applied herbicides was studied following cultivation dependent approach. The microbial community showed a mixed response towards applied herbicides. With a few exceptions, metribuzin displayed a negative, clodinafop a positive and sulphonylurea herbicides a neutral effect while as the effect of isoproturon was variable. Significant toxic impact of UPH-110 was mostly observed at higher concentrations (@ 600 and 1000 g ha-1. The magnitude of hazard and duration of toxicity increased as the dose of UPH-110 increased. The influence whether positive or negative, was only transitory in nature and recovered to the level of untreated microcosms by or before 30th day of application. Among the microbial groups studied, fungal population was least affected at field rate, bacteria, actinomycetes and Azotobacter showed mixed response while as the phosphorus solubilizers population showed a tendency to increase in response to the applied herbicides.The herbicidal impact on soil microbial population was found to depend on the nature and dose of herbicide used and also the type of microbial group

  12. Microbial assessment of cabin air quality on commercial airliners

    Science.gov (United States)

    La Duc, Myron T.; Stuecker, Tara; Bearman, Gregory; Venkateswaran, Kasthuri

    2005-01-01

    The microbial burdens of 69 cabin air samples collected from commercial airliners were assessed via conventional culture-dependent, and molecular-based microbial enumeration assays. Cabin air samples from each of four separate flights aboard two different carriers were collected via air-impingement. Microbial enumeration techniques targeting DNA, ATP, and endotoxin were employed to estimate total microbial burden. The total viable microbial population ranged from 0 to 3.6 x10 4 cells per 100 liters of air, as assessed by the ATP-assay. When these same samples were plated on R2A minimal medium, anywhere from 2% to 80% of these viable populations were cultivable. Five of the 29 samples examined exhibited higher cultivable counts than ATP derived viable counts, perhaps a consequence of the dormant nature (and thus lower concentration of intracellular ATP) of cells inhabiting these air cabin samples. Ribosomal RNA gene sequence analysis showed these samples to consist of a moderately diverse group of bacteria, including human pathogens. Enumeration of ribosomal genes via quantitative-PCR indicated that population densities ranged from 5 x 10 1 ' to IO 7 cells per 100 liters of air. Each of the aforementioned strategies for assessing overall microbial burden has its strengths and weaknesses; this publication serves as a testament to the power of their use in concert.

  13. Microbial bioinformatics 2020.

    Science.gov (United States)

    Pallen, Mark J

    2016-09-01

    Microbial bioinformatics in 2020 will remain a vibrant, creative discipline, adding value to the ever-growing flood of new sequence data, while embracing novel technologies and fresh approaches. Databases and search strategies will struggle to cope and manual curation will not be sustainable during the scale-up to the million-microbial-genome era. Microbial taxonomy will have to adapt to a situation in which most microorganisms are discovered and characterised through the analysis of sequences. Genome sequencing will become a routine approach in clinical and research laboratories, with fresh demands for interpretable user-friendly outputs. The "internet of things" will penetrate healthcare systems, so that even a piece of hospital plumbing might have its own IP address that can be integrated with pathogen genome sequences. Microbiome mania will continue, but the tide will turn from molecular barcoding towards metagenomics. Crowd-sourced analyses will collide with cloud computing, but eternal vigilance will be the price of preventing the misinterpretation and overselling of microbial sequence data. Output from hand-held sequencers will be analysed on mobile devices. Open-source training materials will address the need for the development of a skilled labour force. As we boldly go into the third decade of the twenty-first century, microbial sequence space will remain the final frontier! PMID:27471065

  14. Nutrient and physical profile data from four Microbial Exchanges and Coupling in Coastal Atlantic Systems (MECCAS) cruises collected aboard the R/V Gyre at the mouth of the Chesapeake Bay and northern Atlantic Ocean from February 17, 1985 to September 7, 1986 (NODC Accession 8800324)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microbial Exchanges and Coupling in Coastal Atlantic Systems (MECCAS) cruise data collected aboard the R/V Gyre at the mouth of the Chesapeake Bay and northern...

  15. The Microbial Olympics.

    Science.gov (United States)

    Youle, Merry; Rohwer, Forest; Stacy, Apollo; Whiteley, Marvin; Steel, Bradley C; Delalez, Nicolas J; Nord, Ashley L; Berry, Richard M; Armitage, Judith P; Kamoun, Sophien; Hogenhout, Saskia; Diggle, Stephen P; Gurney, James; Pollitt, Eric J G; Boetius, Antje; Cary, S Craig

    2012-08-01

    Every four years, the Olympic Games plays host to competitors who have built on their natural talent by training for many years to become the best in their chosen discipline. Similar spirit and endeavour can be found throughout the microbial world, in which every day is a competition to survive and thrive. Microorganisms are trained through evolution to become the fittest and the best adapted to a particular environmental niche or lifestyle, and to innovate when the 'rules of the game' are changed by alterations to their natural habitats. In this Essay, we honour the best competitors in the microbial world by inviting them to take part in the inaugural Microbial Olympics. PMID:22796885

  16. Microbial Life in Soil - Linking Biophysical Models with Observations

    Science.gov (United States)

    Or, Dani; Tecon, Robin; Ebrahimi, Ali; Kleyer, Hannah; Ilie, Olga; Wang, Gang

    2015-04-01

    Microbial life in soil occurs within fragmented aquatic habitats formed in complex pore spaces where motility is restricted to short hydration windows (e.g., following rainfall). The limited range of self-dispersion and physical confinement promote spatial association among trophically interdepended microbial species. Competition and preferences for different nutrient resources and byproducts and their diffusion require high level of spatial organization to sustain the functioning of multispecies communities. We report mechanistic modeling studies of competing multispecies microbial communities grown on hydrated surfaces and within artificial soil aggregates (represented by 3-D pore network). Results show how trophic dependencies and cell-level interactions within patchy diffusion fields promote spatial self-organization of motile microbial cells. The spontaneously forming patterns of segregated, yet coexisting species were robust to spatial heterogeneities and to temporal perturbations (hydration dynamics), and respond primarily to the type of trophic dependencies. Such spatially self-organized consortia may reflect ecological templates that optimize substrate utilization and could form the basic architecture for more permanent surface-attached microbial colonies. Hydration dynamics affect structure and spatial arrangement of aerobic and anaerobic microbial communities and their biogeochemical functions. Experiments with well-characterized artificial soil microbial assemblies grown on porous surfaces provide access to community dynamics during wetting and drying cycles detected through genetic fingerprinting. Experiments for visual observations of spatial associations of tagged bacterial species with known trophic dependencies on model porous surfaces are underway. Biophysical modeling provide a means for predicting hydration-mediated critical separation distances for activation of spatial self-organization. The study provides new modeling and observational tools

  17. Audio Interfaces for Improved Accessibility

    OpenAIRE

    Duarte, Carlos; Carrico, Lu&#;s

    2008-01-01

    This chapter focused on how endowing interfaces with audio interaction capabilities can improve their accessibility. To exemplify this outcome the development of several versions of a Digital Talking Book player was presented. This allowed us to show it is possible to maintain the same set of features while stripping the interface of visual components, and still keep it usable for the visually impaired population. The interface development concerns focused on both ends of the interaction spec...

  18. Population success.

    Science.gov (United States)

    1982-01-01

    . Access to contraceptives is, of course, a major influence on fertility decline. According to UNFPA some of the Latin American countries have the highest contraceptive use among developing countries. The countries of Asia come next and contraceptives are least used in sub-Saharan Africa where birth rates of 45/1000 are still common. The money for population programs, says the report, has come largely from developing countries themselves. A survey of 15 countries showed them to have contributed 67% out of their own budgets--the rest having come from external aid. And in programs aided by UNFPA the local input has been even higher. During 1979-1981 the developing countries themselves budgeted $4.6 for each dollar budgeted by UNFPA. The report also highlights some of the emerging problems for the next 2 decades--and which will be high on the agenda of the 1984 conference. These include "uncontrolled urban growth" in developing countries as well as an important change in overall population age structure as more and more old people survive. Aging populations are of particular concern to the developed countries but, as the report points out, even countries like China--which has achieved a steep drop in fertility and mortality--will face the problems of an aging population by the year 2000. PMID:12279227

  19. Microbial Corrosion: 1988 Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    None

    1989-04-01

    Microbial action can greatly increase corrosion damage in power plant water systems. This workshop pulled together practical experience and theoretical knowledge on microbially induced corrosion, documented diagnostic and treatment methods, and identified areas for future research.

  20. CERN Access Cards and Access Authorisations

    CERN Multimedia

    2003-01-01

    From the 01/05/2003, all problems relating to access cards and refusal of access to any zone, building or experiment within CERN must be addressed to the Centrale de Surveillance des Accès (CSA building 120) on 78877 or send an e-mail to Access.Surveillance@cern.ch. The responsibles for CERN access control have put into place a procedure with the CSA, Service Enregistrement and the Technical Control Room, to make sure that all problems get resolved in a proper and timely manner.

  1. Glitch Statistics of Radio Pulsars : Multiple populations

    CERN Document Server

    Konar, Sushan

    2014-01-01

    There appears to be more than one statistically different populations in the energy distribution of glitches, strongly indicative of different mechanisms accessing different energy ranges responsible for them.

  2. Effect of wildfires on the genetic microbial diversity in forest soils from Canary Islands (Spain)

    OpenAIRE

    Rodríguez, J.; A. Turmero; J. A. González-Pérez; F.J. González-Vila; C. Arbelo; Rodríguez-Rodríguez, A.; M.I Pérez-Leblic; M.E. Arias

    2013-01-01

    Wildfires produce several ecological and environmental impacts on the physical and chemical soil characteristics, as well as on the properties and dynamics of soil microbial populations. Microorganisms are good indicators of ecosystem function and sustainability and therefore the studies about the impact of fire on microbial communities is relevant to understand the role of fire in ecosystem functioning. Although several authors have provided data about total microbial biomass and activity in...

  3. Accessibility and sensory experiences

    DEFF Research Database (Denmark)

    Ryhl, Camilla

    2010-01-01

    This article introduces a new design concept; sensory accessibility. While acknowledging the importance of sensory experiences in architectural quality, as well as the importance of accommodating user needs the concept combines three equally important factors; architecture, the senses...... and accessibility. Sensory accessibility accommodates aspects of a sensory disability and describes architectural design requirements needed to ensure access to architectural experiences. In the context of architecture accessibility has become a design concept of its own. It is generally described as ensuring...

  4. Molecular ecology of microbial mats

    NARCIS (Netherlands)

    H. Bolhuis; M.S. Cretoiu; L.J. Stal

    2014-01-01

    Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep

  5. Effect of wildfires on the genetic microbial diversity in forest soils from Canary Islands (Spain

    Directory of Open Access Journals (Sweden)

    J. Rodríguez

    2013-05-01

    Full Text Available Wildfires produce several ecological and environmental impacts on the physical and chemical soil characteristics, as well as on the properties and dynamics of soil microbial populations. Microorganisms are good indicators of ecosystem function and sustainability and therefore the studies about the impact of fire on microbial communities is relevant to understand the role of fire in ecosystem functioning. Although several authors have provided data about total microbial biomass and activity in soils affected by fires, there is little information about the composition and evolution of soil microbial populations after the passage of fire. In this work the effect of wildfires on the genetic diversity of microbial populations in soils from the island of Tenerife (Canary Islands, Spain is studied. The final objective was to get information about the recovery of soil functionality after wildfires.

  6. Diazotrophic microbial mats

    NARCIS (Netherlands)

    I. Severin; L.J. Stal

    2010-01-01

    Microbial mats have been the focus of scientific research for a few decades. These small-scale ecosystems are examples of versatile benthic communities of microorganisms, usually dominated by phototrophic bacteria (e.g., Krumbein et al., 1977; Jørgensen et al., 1983). They develop as vertically stra

  7. SEAGRASS RHIZOSPHERE MICROBIAL COMMUNITIES

    Science.gov (United States)

    Devereux, Richard. 2005. Seagrass Rhizosphere Microbial Communities. In: Interactions Between Macro- and Microorganisms in Marine Sediments. E. Kristense, J.E. Kostka and R.H. Haese, Editors. American Geophysical Union, Washington, DC. p199-216. (ERL,GB 1213). Seagrasses ...

  8. 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

  9. An environment-sensitive synthetic microbial ecosystem.

    Directory of Open Access Journals (Sweden)

    Bo Hu

    Full Text Available Microbial ecosystems have been widely used in industrial production, but the inter-relationships of organisms within them haven't been completely clarified due to complex composition and structure of natural microbial ecosystems. So it is challenging for ecologists to get deep insights on how ecosystems function and interplay with surrounding environments. But the recent progresses in synthetic biology show that construction of artificial ecosystems where relationships of species are comparatively clear could help us further uncover the meadow of those tiny societies. By using two quorum-sensing signal transduction circuits, this research designed, simulated and constructed a synthetic ecosystem where various population dynamics formed by changing environmental factors. Coherent experimental data and mathematical simulation in our study show that different antibiotics levels and initial cell densities can result in correlated population dynamics such as extinction, obligatory mutualism, facultative mutualism and commensalism. This synthetic ecosystem provides valuable information for addressing questions in ecology and may act as a chassis for construction of more complex microbial ecosystems.

  10. Final Report: Role of microbial synergies in immobilization of metals

    Energy Technology Data Exchange (ETDEWEB)

    Slava Epstein, Ph.D. and Kim Lewis, Ph.D.

    2012-11-14

    This Subsurface Microbial Ecology and Community Dynamics project tested the following hypothesis: synergistic groups of microorganisms immobilize heavy elements more efficiently than do individual species. We focused on groundwater at several DOE FRC and their microbial communities affecting the fate of U, Tc, and Cr. While we did not obtain evidence to support the original hypothesis, we developed a platform to accessing novel species from the target environments. We implemented this technology and discovered and isolated novel species capable of immobilization of uranium and species with exceptionally high resistances to the extant toxic factors. We have sequenced their genomes are are in the process of investigating the genomic contents behind these surprising resistances.

  11. Microbially induced corrosion of carbon steel in deep groundwater environment

    Directory of Open Access Journals (Sweden)

    Pauliina eRajala

    2015-07-01

    Full Text Available The metallic low and intermediate level radioactive waste generally consists of carbon steel and stainless steels. The corrosion rate of carbon steel in deep groundwater is typically low, unless the water is very acidic or microbial activity in the environment is high. Therefore, the assessment of microbially induced corrosion of carbon steel in deep bedrock environment has become important for evaluating the safety of disposal of radioactive waste. Here we studied the corrosion inducing ability of indigenous microbial community from a deep bedrock aquifer. Carbon steel coupons were exposed to anoxic groundwater from repository site 100 m depth (Olkiluoto, Finland for periods of three and eight months. The experiments were conducted at both in situ temperature and room temperature to investigate the response of microbial population to elevated temperature. Our results demonstrate that microorganisms from the deep bedrock aquifer benefit from carbon steel introduced to the nutrient poor anoxic deep groundwater environment. In the groundwater incubated with carbon steel the planktonic microbial community was more diverse and 100-fold more abundant compared to the environment without carbon steel. The betaproteobacteria were the most dominant bacterial class in all samples where carbon steel was present, whereas in groundwater incubated without carbon steel the microbial community had clearly less diversity. Microorganisms induced pitting corrosion and were found to cluster inside the corrosion pits. Temperature had an effect on the species composition of microbial community and also affected the corrosion deposits layer formed on the surface of carbon steel.

  12. Microbially induced corrosion of carbon steel in deep groundwater environment

    Science.gov (United States)

    Rajala, Pauliina; Carpén, Leena; Vepsäläinen, Mikko; Raulio, Mari; Sohlberg, Elina; Bomberg, Malin

    2015-01-01

    The metallic low and intermediate level radioactive waste generally consists of carbon steel and stainless steels. The corrosion rate of carbon steel in deep groundwater is typically low, unless the water is very acidic or microbial activity in the environment is high. Therefore, the assessment of microbially induced corrosion of carbon steel in deep bedrock environment has become important for evaluating the safety of disposal of radioactive waste. Here we studied the corrosion inducing ability of indigenous microbial community from a deep bedrock aquifer. Carbon steel coupons were exposed to anoxic groundwater from repository site 100 m depth (Olkiluoto, Finland) for periods of 3 and 8 months. The experiments were conducted at both in situ temperature and room temperature to investigate the response of microbial population to elevated temperature. Our results demonstrate that microorganisms from the deep bedrock aquifer benefit from carbon steel introduced to the nutrient poor anoxic deep groundwater environment. In the groundwater incubated with carbon steel the planktonic microbial community was more diverse and 100-fold more abundant compared to the environment without carbon steel. The betaproteobacteria were the most dominant bacterial class in all samples where carbon steel was present, whereas in groundwater incubated without carbon steel the microbial community had clearly less diversity. Microorganisms induced pitting corrosion and were found to cluster inside the corrosion pits. Temperature had an effect on the species composition of microbial community and also affected the corrosion deposits layer formed on the surface of carbon steel. PMID:26257707

  13. The effect of D123 wheat as a companion crop on soil enzyme activities, microbial biomass and microbial communities in the rhizosphere of watermelon.

    Science.gov (United States)

    Xu, Weihui; Wang, Zhigang; Wu, Fengzhi

    2015-01-01

    The growth of watermelon is often threatened by Fusarium oxysporum f. sp. niveum (Fon) in successively monocultured soil, which results in economic loss. The objective of this study was to investigate the effect of D123 wheat as a companion crop on soil enzyme activities, microbial biomass and microbial communities in the rhizosphere of watermelon and to explore the relationship between the effect and the incidence of wilt caused by Fon. The results showed that the activities of soil polyphenol oxidase, urease and invertase were increased, the microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) were significantly increased, and the ratio of MBC/MBN was decreased (P activities and microbial biomass, decreased the Fon population, and changed the relative abundance of microbial communities in the rhizosphere of watermelon, which may be related to the reduction of Fusarium wilt in the watermelon/wheat companion system. PMID:26388851

  14. Effect of different salt adaptation strategies on the microbial diversity, activity, and settling of nitrifying sludge in sequencing batch reactors

    NARCIS (Netherlands)

    Bassin, J.P.; Kleerebezem, R.; Muyzer, G.; Rosado, A.S.; Van Loosdrecht, M.C.M.; Dezotti, M.

    2011-01-01

    The effect of salinity on the activity of nitrifying bacteria, floc characteristics, and microbial community structure accessed by fluorescent in situ hybridization and polymerase chain reaction–denaturing gradient gel electrophoresis techniques was investigated. Two sequencing batch reactors (SRB1

  15. Role of cryptic genes in microbial evolution.

    Science.gov (United States)

    Hall, B G; Yokoyama, S; Calhoun, D H

    1983-12-01

    Cryptic genes are phenotypically silent DNA sequences, not normally expressed during the life cycle of an individual. They may, however, be activated in a few individuals of a large population by mutation, recombination, insertion elements, or other genetic mechanisms. A consideration of the microbial literature concerning biochemical evolution, physiology, and taxonomy provides the basis for a hypothesis of microbial adaptation and evolution by mutational activation of cryptic genes. Evidence is presented, and a mathematical model is derived, indicating that powerful and biologically important mechanisms exist to prevent the loss of cryptic genes. We propose that cryptic genes persist as a vital element of the genetic repertoire, ready for recall by mutational activation in future generations. Cryptic genes provide a versatile endogenous genetic reservoir that enhances the adaptive potential of a species by a mechanism that is independent of genetic exchange.

  16. Rhizosphere microbial community and its response to plant species and soil history

    NARCIS (Netherlands)

    Garbeva, P.; van Elsas, J. D.; van Veen, J. A.

    2008-01-01

    The plant rhizosphere is a dynamic environment in which many parameters may influence the population structure, diversity and activity of the microbial community. Two important factors determining the structure of microbial community present in the vicinity of plant roots are plant species and soil

  17. The Microbial Resource Research Infrastructure MIRRI: Strength through Coordination.

    Science.gov (United States)

    Stackebrandt, Erko; Schüngel, Manuela; Martin, Dunja; Smith, David

    2015-11-18

    Microbial resources have been recognized as essential raw materials for the advancement of health and later for biotechnology, agriculture, food technology and for research in the life sciences, as their enormous abundance and diversity offer an unparalleled source of unexplored solutions. Microbial domain biological resource centres (mBRC) provide live cultures and associated data to foster and support the development of basic and applied science in countries worldwide and especially in Europe, where the density of highly advanced mBRCs is high. The not-for-profit and distributed project MIRRI (Microbial Resource Research Infrastructure) aims to coordinate access to hitherto individually managed resources by developing a pan-European platform which takes the interoperability and accessibility of resources and data to a higher level. Providing a wealth of additional information and linking to datasets such as literature, environmental data, sequences and chemistry will enable researchers to select organisms suitable for their research and enable innovative solutions to be developed. The current independent policies and managed processes will be adapted by partner mBRCs to harmonize holdings, services, training, and accession policy and to share expertise. The infrastructure will improve access to enhanced quality microorganisms in an appropriate legal framework and to resource-associated data in a more interoperable way.

  18. Applying landscape genetics to the microbial world.

    Science.gov (United States)

    Dudaniec, Rachael Y; Tesson, Sylvie V M

    2016-07-01

    Landscape genetics, which explicitly quantifies landscape effects on gene flow and adaptation, has largely focused on macroorganisms, with little attention given to microorganisms. This is despite overwhelming evidence that microorganisms exhibit spatial genetic structuring in relation to environmental variables. The increasing accessibility of genomic data has opened up the opportunity for landscape genetics to embrace the world of microorganisms, which may be thought of as 'the invisible regulators' of the macroecological world. Recent developments in bioinformatics and increased data accessibility have accelerated our ability to identify microbial taxa and characterize their genetic diversity. However, the influence of the landscape matrix and dynamic environmental factors on microorganism genetic dispersal and adaptation has been little explored. Also, because many microorganisms coinhabit or codisperse with macroorganisms, landscape genomic approaches may improve insights into how micro- and macroorganisms reciprocally interact to create spatial genetic structure. Conducting landscape genetic analyses on microorganisms requires that we accommodate shifts in spatial and temporal scales, presenting new conceptual and methodological challenges not yet explored in 'macro'-landscape genetics. We argue that there is much value to be gained for microbial ecologists from embracing landscape genetic approaches. We provide a case for integrating landscape genetic methods into microecological studies and discuss specific considerations associated with the novel challenges this brings. We anticipate that microorganism landscape genetic studies will provide new insights into both micro- and macroecological processes and expand our knowledge of species' distributions, adaptive mechanisms and species' interactions in changing environments.

  19. Assembly-driven community genomics of a hypersaline microbial ecosystem.

    Directory of Open Access Journals (Sweden)

    Sheila Podell

    Full Text Available Microbial populations inhabiting a natural hypersaline lake ecosystem in Lake Tyrrell, Victoria, Australia, have been characterized using deep metagenomic sampling, iterative de novo assembly, and multidimensional phylogenetic binning. Composite genomes representing habitat-specific microbial populations were reconstructed for eleven different archaea and one bacterium, comprising between 0.6 and 14.1% of the planktonic community. Eight of the eleven archaeal genomes were from microbial species without previously cultured representatives. These new genomes provide habitat-specific reference sequences enabling detailed, lineage-specific compartmentalization of predicted functional capabilities and cellular properties associated with both dominant and less abundant community members, including organisms previously known only by their 16S rRNA sequences. Together, these data provide a comprehensive, culture-independent genomic blueprint for ecosystem-wide analysis of protein functions, population structure, and lifestyles of co-existing, co-evolving microbial groups within the same natural habitat. The "assembly-driven" community genomic approach demonstrated in this study advances our ability to push beyond single gene investigations, and promotes genome-scale reconstructions as a tangible goal in the quest to define the metabolic, ecological, and evolutionary dynamics that underpin environmental microbial diversity.

  20. Professional Access 2013 programming

    CERN Document Server

    Hennig, Teresa; Hepworth, George; Yudovich, Dagi (Doug)

    2013-01-01

    Authoritative and comprehensive coverage for building Access 2013 Solutions Access, the most popular database system in the world, just opened a new frontier in the Cloud. Access 2013 provides significant new features for building robust line-of-business solutions for web, client and integrated environments.  This book was written by a team of Microsoft Access MVPs, with consulting and editing by Access experts, MVPs and members of the Microsoft Access team. It gives you the information and examples to expand your areas of expertise and immediately start to develop and upgrade projects. Exp

  1. Standing variation in spatially growing populations

    Science.gov (United States)

    Fusco, Diana; Gralka, Matti; Kayser, Jona; Hallatschek, Oskar

    Patterns of genetic diversity not only reflect the evolutionary history of a species but they can also determine the evolutionary response to environmental change. For instance, the standing genetic diversity of a microbial population can be key to rescue in the face of an antibiotic attack. While genetic diversity is in general shaped by both demography and evolution, very little is understood when both factors matter, as e.g. for biofilms with pronounced spatial organization. Here, we quantitatively explore patterns of genetic diversity by using microbial colonies and well-mixed test tube populations as antipodal model systems with extreme and very little spatial structure, respectively. We find that Eden model simulations and KPZ theory can remarkably reproduce the genetic diversity in microbial colonies obtained via population sequencing. The excellent agreement allows to draw conclusions on the resilience of spatially-organized populations and to uncover new strategies to contain antibiotic resistance.

  2. Public coastal access in Nova Scotia's coastal strategy

    OpenAIRE

    Joshua Kelly Mackintosh

    2011-01-01

    Public coastal access is an issue that affects coastal communities and coastal populations worldwide. One such place where public coastal access is of particular relevance is the Province of Nova Scotia, Canada where the government is developing a provincial Coastal Strategy to address priority coastal management issues, one of which is public coastal access. This study examines best practices in public coastal access in selected US States and their potential application in study areas in Nov...

  3. A comparison between a yeast cell wall extract (Bio-Mos® and palm kernel expeller as mannan-oligosaccharides sources on the performance and ileal microbial population of broiler chickens

    Directory of Open Access Journals (Sweden)

    Bahman Navidshad

    2015-02-01

    Full Text Available The present study was conducted to determine the effect of a yeast cell wall extract (Bio- Mos and palm kernel expeller (PKE on the performance, nutrient digestibility, and ileal bacteria population of broiler chickens. A total of 60 1-d-old male broiler chicks (Cobb 500 were fed one of the 3 isonitrogenous and isocaloric diet including a control diet, or a control diet supplemented with 2 g/kg Bio-Mos (1-42 d, and for the third group, the control diet at 1-28 d following a diet containing 200 g/kg of an enzymatically-treated PKE at 29-42 d. The weight gains of birds fed the PKE containing diet (96.17 g/d were less than other groups (109.10 and 104.42 g/d for the Bio-Mos and control diet, respectively (P0.05, but the birds fed PKE or Bio-Mos containing diets had a lower population of Escherichia coli than the control group (P<0.05. The results showed that PKE potentially has a prebiotic property for chicken; however, a 200 g/kg dietary inclusion rate of PKE is not commercially recommendable because of its negative effects on the nutrients digestibility.

  4. Segregation of the Anodic Microbial Communities in a Microbial Fuel Cell Cascade

    Science.gov (United States)

    Hodgson, Douglas M.; Smith, Ann; Dahale, Sonal; Stratford, James P.; Li, Jia V.; Grüning, André; Bushell, Michael E.; Marchesi, Julian R.; Avignone Rossa, C.

    2016-01-01

    Metabolic interactions within microbial communities are essential for the efficient degradation of complex organic compounds, and underpin natural phenomena driven by microorganisms, such as the recycling of carbon-, nitrogen-, and sulfur-containing molecules. These metabolic interactions ultimately determine the function, activity and stability of the community, and therefore their understanding would be essential to steer processes where microbial communities are involved. This is exploited in the design of microbial fuel cells (MFCs), bioelectrochemical devices that convert the chemical energy present in substrates into electrical energy through the metabolic activity of microorganisms, either single species or communities. In this work, we analyzed the evolution of the microbial community structure in a cascade of MFCs inoculated with an anaerobic microbial community and continuously fed with a complex medium. The analysis of the composition of the anodic communities revealed the establishment of different communities in the anodes of the hydraulically connected MFCs, with a decrease in the abundance of fermentative taxa and a concurrent increase in respiratory taxa along the cascade. The analysis of the metabolites in the anodic suspension showed a metabolic shift between the first and last MFC, confirming the segregation of the anodic communities. Those results suggest a metabolic interaction mechanism between the predominant fermentative bacteria at the first stages of the cascade and the anaerobic respiratory electrogenic population in the latter stages, which is reflected in the observed increase in power output. We show that our experimental system represents an ideal platform for optimization of processes where the degradation of complex substrates is involved, as well as a potential tool for the study of metabolic interactions in complex microbial communities. PMID:27242723

  5. Stress-driven speciation in novel strains of Bacillus isolated from a microbial community in the Mojave Desert, a Mars-analog

    Science.gov (United States)

    Wan, J.; Lera, M.; Marcu, O.

    2012-12-01

    Microbial communities are composed of complex multispecies that coevolve within the constraints of the environment over time. In the harsh, desiccated regions of the Mojave Desert, a Mars-analog, the microbial community in the surface layer is exposed to daily and seasonal fluctuations in temperature, humidity, nutrients, and UV index. Strategies of adaptation to physical factors in a microbial microenvironment determine the limits of adaptation and survival to sudden climate changes, with implications for planetary habitability. Here we show that novel strains of Bacillus niacini and B. thuringiensis isolated from the top soil of the Mojave Desert are differentially adapted to selective pressures imposed by caloric restriction and oxidative stress and show distinct social interactions. Metabolic profiling using Biolog plates for all isolates showed drastically different "metabolic fingerprints," with some only able to utilize very specific carbon sources in contrast to others that were able to breakdown most sources but for only a limited time. The stress response to hydrogen peroxide was also differential, with catalase activity levels of the Bacillus species from Mojave being much lower than the control species of soil Bacillus, suggesting that their survival may depend on other microbes from the same community for protection from oxidative damage. We also investigated the social communication and interaction of the four strains by spatial microenvironment assays, and uncovered unusual swarming and swimming abilities through motility assays. The cooperation and conflict in the microbial population reflect adaptations to oxidative stress and caloric restriction, which can be the driving forces for differences in phenotypes, interactions, metabolic ability, and ultimately, speciation. This study supports the theory of codependencies of organisms in a community for protection or access to "public goods" for survival in a harsh, fluctuating environment, and

  6. Physical Access Control Database

    Data.gov (United States)

    Department of Transportation — This data set contains the personnel access card data (photo, name, activation/expiration dates, card number, and access level) as well as data about turnstiles and...

  7. Engineering microbial consortia to enhance biomining and bioremediation

    Directory of Open Access Journals (Sweden)

    Karl Dietrich Brune

    2012-06-01

    Full Text Available In natural environments microorganisms commonly exist as communities of multiple species that are capable of performing more varied and complicated tasks than clonal populations. Synthetic biologists have engineered clonal populations with characteristics such as differentiation, memory and pattern formation, which are usually associated with more complex multicellular organisms. The prospect of designing microbial communities has alluring possibilities for environmental, biomedical and energy applications and is likely to reveal insight into how natural microbial consortia function. Cell signaling and communication pathways between different species are likely to be key processes for designing novel functions in synthetic and natural consortia. Recent efforts to engineer synthetic microbial interactions will be reviewed here, with particular emphasis given to research with significance for industrial applications in the field of biomining and bioremediation of acid mine drainage.

  8. Microbial biomass and activity in subsurface sediments from Vejen, Denmark

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Winding, Anne

    1992-01-01

    of bacteria varied from 0.5 to 1,203 x 103 colony forming units/g dry weight (gdw); total numbers of bacteria acridine orange direct counts (AODC) varied from 1.7 to 147 × 107 cells/gdw; growth rates (incorporation of [3H]-thymidine) varied from 1.4 to 60.7 × 104 cells/(gdw · day); and rate constants...... a single abiotic parameter that could explain the variation of size and activity of the microbial population. The microbial data obtained in these geologically young sediments were compared to literature data from older sediments, and this comparison showed that age and type of geological formation might...... be important for the size and activity of the microbial populations....

  9. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB. PMID:15289671

  10. Microbial Risk Assessment

    Science.gov (United States)

    Ott, C. M.; Mena, K. D.; Nickerson, C.A.; Pierson, D. L.

    2009-01-01

    Historically, microbiological spaceflight requirements have been established in a subjective manner based upon expert opinion of both environmental and clinical monitoring results and the incidence of disease. The limited amount of data, especially from long-duration missions, has created very conservative requirements based primarily on the concentration of microorganisms. Periodic reevaluations of new data from later missions have allowed some relaxation of these stringent requirements. However, the requirements remain very conservative and subjective in nature, and the risk of crew illness due to infectious microorganisms is not well defined. The use of modeling techniques for microbial risk has been applied in the food and potable water industries and has exceptional potential for spaceflight applications. From a productivity standpoint, this type of modeling can (1) decrease unnecessary costs and resource usage and (2) prevent inadequate or inappropriate data for health assessment. In addition, a quantitative model has several advantages for risk management and communication. By identifying the variable components of the model and the knowledge associated with each component, this type of modeling can: (1) Systematically identify and close knowledge gaps, (2) Systematically identify acceptable and unacceptable risks, (3) Improve communication with stakeholders as to the reasons for resource use, and (4) Facilitate external scientific approval of the NASA requirements. The modeling of microbial risk involves the evaluation of several key factors including hazard identification, crew exposure assessment, dose-response assessment, and risk characterization. Many of these factors are similar to conditions found on Earth; however, the spaceflight environment is very specialized as the inhabitants live in a small, semi-closed environment that is often dependent on regenerative life support systems. To further complicate modeling efforts, microbial dose

  11. Access Customized Forms

    OpenAIRE

    Cosma Emil; Jeflea Victor

    2010-01-01

    By using Word, Excel or PowerPoint one can automate routine operations using the VBA language (Visual Basic for Applications). This language is also used in Access, allowing access to data stored in tables or queries. Thus, Access and VBA resources can be used together. Access is designed for programming forms and reports (among other things), so there won’t be found any of the VBA editor’s specific forms.

  12. 元素硫对黄铜矿生物浸出行为及群落结构的影响%Relationships among bioleaching performance, additional elemental sulfur,microbial population dynamics and its energy metabolism in bioleaching of chalcopyrite

    Institute of Scientific and Technical Information of China (English)

    夏乐先; 汤露; 夏金兰; 尹礎; 柴立元; 赵小娟; 聂珍媛; 柳建设; 邱冠周

    2012-01-01

    To estimate the relationships among bioleaching performance,additional elemental sulfur (S0),microbial population dynamics and its energy metabolism,bioleaching of chalcopyrite by three typical sulfur- and/or iron-oxidizing bacteria,Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum and Acidithiobacillus thiooxidans with different levels of sulfur were studied in batch shake flask cultures incubated at 30 ℃.Copper dissolution capability (71%) was increased with the addition of 3.193 g/L S0,compared to that (67%) without S0.However,lower copper extraction was obtained in bioleaching with excessive sulfur.Microbial population dynamics during chalcopyrite bioleaching process was monitored by using PCR-restrietion fragment length polymorphism (PCR-RFLP).Additional S0 accelerated the growth of sulfur-oxidizing bacteria,inhibited the iron-oxidizing metabolism and led to the decrease of iron-oxidizing microorganisms,finally affected iron concentration,redox potential and bioleaching performance.It is suggested that mixed iron and sulfur-oxidizing microorganisms with further optimized additional S0 concentration could improve copper recovery from chalcopyrite.%研究3种典型铁/硫代谢菌-Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum及Acidithiobacillus thiooxidans混合浸出黄铜矿过程中铁/硫氧化活性、群落结构(PCR-RFLP)的变化,以及不同浓度的元素硫对其影响.结果发现,加入3.193 g/L元素硫能促进细菌的表观硫氧化活性,改变浸矿体系的群落结构,并进一步影响钝化层的形成、金属离子的溶出,其浸出率(71%)较未添加硫的(67%)有一定程度的提高.而过量的元素硫会抑制铜的浸出(浸出率44%).

  13. Microbial "social networks"

    OpenAIRE

    Fernandez, Mitch; Riveros, Juan D; Campos, Michael; Mathee, Kalai; Narasimhan, Giri

    2015-01-01

    Background It is well understood that distinct communities of bacteria are present at different sites of the body, and that changes in the structure of these communities have strong implications for human health. Yet, challenges remain in understanding the complex interconnections between the bacterial taxa within these microbial communities and how they change during the progression of diseases. Many recent studies attempt to analyze the human microbiome using traditional ecological measures...

  14. Microbial Production of Biovanillin

    OpenAIRE

    Converti, A.; Aliakbarian, B.; Domínguez, J.M.; Bustos Vázquez, G.; Perego, P.

    2010-01-01

    This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxi...

  15. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year's report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  16. Microbial field pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year`s report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  17. Role of genomic typing in taxonomy, evolutionary genetics, and microbial epidemiology.

    NARCIS (Netherlands)

    A.F. van Belkum (Alex); M. Struelens; A. de Visser (Arjan); H.A. Verbrugh (Henri); M. Tibayrench

    2001-01-01

    textabstractCurrently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and microbi

  18. Open Access Alternatives

    Science.gov (United States)

    Tenopir, Carol

    2004-01-01

    Open access publishing is a hot topic today. But open access publishing can have many different definitions, and pros and cons vary with the definitions. Open access publishing is especially attractive to companies and small colleges or universities that are likely to have many more readers than authors. A downside is that a membership fee sounds…

  19. Microbial malaise: how can we classify the microbiome?

    Science.gov (United States)

    Beiko, Robert G

    2015-11-01

    The names and lineages of microorganisms are critical to our understanding of the microbiome. However, microbial taxonomy and phylogeny are in perpetual flux, with emerging criteria being used to rename and reshape our views of the microbial world. Different candidate molecular and nonmolecular criteria are often broadly consistent with one another, which underpins the pluralistic approach to taxonomy. However, the taxonomic picture is clouded when underlying criteria are not in agreement, or when reference datasets contain erroneously named organisms. How does the shifting taxonomic landscape impact our interpretation of microbial communities, especially in the face of inconsistencies and errors? How can taxonomy be applied in a consistent way when different users have different requirements of the classifications that emerge? The key path forward involves finding ways to integrate conflicting taxonomic criteria, choosing the right units of analysis for microbiomic studies, and making molecular taxonomy transparent and accessible in a way that complements current genomic resources.

  20. Modeling spatial accessibility to parks: a national study

    Directory of Open Access Journals (Sweden)

    Lu Hua

    2011-05-01

    Full Text Available Abstract Background Parks provide ideal open spaces for leisure-time physical activity and important venues to promote physical activity. The spatial configuration of parks, the number of parks and their spatial distribution across neighborhood areas or local regions, represents the basic park access potential for their residential populations. A new measure of spatial access to parks, population-weighted distance (PWD to parks, combines the advantages of current park access approaches and incorporates the information processing theory and probability access surface model to more accurately quantify residential population's potential spatial access to parks. Results The PWD was constructed at the basic level of US census geography - blocks - using US park and population data. This new measure of population park accessibility was aggregated to census tract, county, state and national levels. On average, US residential populations are expected to travel 6.7 miles to access their local neighborhood parks. There are significant differences in the PWD to local parks among states. The District of Columbia and Connecticut have the best access to local neighborhood parks with PWD of 0.6 miles and 1.8 miles, respectively. Alaska, Montana, and Wyoming have the largest PWDs of 62.0, 37.4, and 32.8 miles, respectively. Rural states in the western and Midwestern US have lower neighborhood park access, while urban states have relatively higher park access. Conclusions The PWD to parks provides a consistent platform for evaluating spatial equity of park access and linking with population health outcomes. It could be an informative evaluation tool for health professionals and policy makers. This new method could be applied to quantify geographic accessibility of other types of services or destinations, such as food, alcohol, and tobacco outlets.

  1. Microbial reduction of iodate

    Science.gov (United States)

    Councell, T.B.; Landa, E.R.; Lovley, D.R.

    1997-01-01

    The different oxidation species of iodine have markedly different sorption properties. Hence, changes in iodine redox states can greatly affect the mobility of iodine in the environment. Although a major microbial role has been suggested in the past to account for these redox changes, little has been done to elucidate the responsible microorganisms or the mechanisms involved. In the work presented here, direct microbial reduction of iodate was demonstrated with anaerobic cell suspensions of the sulfate reducing bacterium Desulfovibrio desulfuricans which reduced 96% of an initial 100 ??M iodate to iodide at pH 7 in 30 mM NaHCO3 buffer, whereas anaerobic cell suspensions of the dissimilatory Fe(III)-reducing bacterium Shewanella putrefaciens were unable to reduce iodate in 30 mM NaHCO3 buffer (pH 7). Both D. desulfuricans and S. putrefaciens were able to reduce iodate at pH 7 in 10 mM HEPES buffer. Both soluble ferrous iron and sulfide, as well as iron monosulfide (FeS) were shown to abiologically reduce iodate to iodide. These results indicate that ferric iron and/or sulfate reducing bacteria are capable of mediating both direct, enzymatic, as well as abiotic reduction of iodate in natural anaerobic environments. These microbially mediated reactions may be important factors in the fate and transport of 129I in natural systems.

  2. Nanoporous microscale microbial incubators.

    Science.gov (United States)

    Ge, Zhifei; Girguis, Peter R; Buie, Cullen R

    2016-02-01

    Reconstruction of phylogenetic trees based on 16S rRNA gene sequencing reveals abundant microbial diversity that has not been cultured in the laboratory. Many attribute this so-called 'great plate count anomaly' to traditional microbial cultivation techniques, which largely facilitate the growth of a single species. Yet, it is widely recognized that bacteria in nature exist in complex communities. One technique to increase the pool of cultivated bacterial species is to co-culture multiple species in a simulated natural environment. Here, we present nanoporous microscale microbial incubators (NMMI) that enable high-throughput screening and real-time observation of multi-species co-culture. The key innovation in NMMI is that they facilitate inter-species communication while maintaining physical isolation between species, which is ideal for genomic analysis. Co-culture of a quorum sensing pair demonstrates that the NMMI can be used to culture multiple species in chemical communication while monitoring the growth dynamics of individual species. PMID:26584739

  3. Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir.

    Science.gov (United States)

    Zhang, Fan; She, Yue-Hui; Li, Hua-Min; Zhang, Xiao-Tao; Shu, Fu-Chang; Wang, Zheng-Liang; Yu, Long-Jiang; Hou, Du-Jie

    2012-08-01

    Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir. More specifically, after nutrients injection, the original dominant populations of Petrobacter and Alishewanella in the production wells almost disappeared. The expected desirable population of Pseudomonas aeruginosa, determined by enrichment experiments in laboratory, was stimulated successfully in two wells of the five monitored wells. Unexpectedly, another potential population of Pseudomonas pseudoalcaligenes which were not detected in the enrichment culture in laboratory was stimulated in the other three monitored production wells. In this study, monitoring of microbial community displayed a comprehensive alteration of microbial populations during the field trial to remedy the deficiency of culture-dependent monitoring methods. The results would help to develop and apply more MEOR processes. PMID:22159733

  4. Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan; Zhang, Xiao-Tao; Hou, Du-Jie [China Univ. of Geosciences, Beijing (China). The Key Lab. of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism; She, Yue-Hui [Yangtze Univ., Jingzhou, Hubei (China). College of Chemistry and Environmental Engineering; Huazhong Univ. of Science and Technology, Wuhan (China). College of Life Science and Technology; Li, Hua-Min [Beijing Bioscience Research Center (China); Shu, Fu-Chang; Wang, Zheng-Liang [Yangtze Univ., Jingzhou, Hubei (China). College of Chemistry and Environmental Engineering; Yu, Long-Jiang [Huazhong Univ. of Science and Technology, Wuhan (China). College of Life Science and Technology

    2012-08-15

    Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir. More specifically, after nutrients injection, the original dominant populations of Petrobacter and Alishewanella in the production wells almost disappeared. The expected desirable population of Pseudomonas aeruginosa, determined by enrichment experiments in laboratory, was stimulated successfully in two wells of the five monitored wells. Unexpectedly, another potential population of Pseudomonas pseudoalcaligenes which were not detected in the enrichment culture in laboratory was stimulated in the other three monitored production wells. In this study, monitoring of microbial community displayed a comprehensive alteration of microbial populations during the field trial to remedy the deficiency of culture-dependent monitoring methods. The results would help to develop and apply more MEOR processes. (orig.)

  5. MOLECULAR DIVERSITY OF DRINKING WATER MICROBIAL COMMUNITIES: A PHYLOGENETIC APPROACH

    Science.gov (United States)

    The microbiological quality of drinking water is assessed using culture-based methods that are highly selective and that tend to underestimate the densities and diversity of microbial populations inhabiting distribution systems. In order to better understand the effect of differe...

  6. Soil microbial community diversity and driving mechanisms

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To study the structure of soil microbial communities, DNA was extracted from different environmental soil samples, and 16S rDNA clone libraries were constructed. The diversity of these 16S libraries were analyzed with restriction fragment length polymorphism based on amplification ribosomal DNA restriction analysis (RFLP-ARDRA)method. The results reveal a high diversity of the soil microbial communities, and striking differences in community structure at different depths. In the surface soil environment, there is no dominant gene pattern, but in the subsurface samples some dominant gene patterns are much more common. With the increasing depth the preference dominance becomes more significant. A spatial isolation hypothesis is proposed to explain the different community structures at different soil depths. Microcosms are set to simulate competition between populations at different degrees of spatial isolation. These studies reveal that spatial isolation caused by low moisture affects the competitive interactions of the two populations. In the two-strain microcosm there is one dominant population at high moisture, and no dominance in very dry environments

  7. Quantitative Fluorescence In Situ Hybridization of Microbial Communities in the Rumens of Cattle Fed Different Diets▿

    OpenAIRE

    Kong, Yunhong; He, Maolong; McAlister, Tim; Seviour, Robert; Forster, Robert

    2010-01-01

    At present there is little quantitative information on the identity and composition of bacterial populations in the rumen microbial community. Quantitative fluorescence in situ hybridization using newly designed oligonucleotide probes was applied to identify the microbial populations in liquid and solid fractions of rumen digesta from cows fed barley silage or grass hay diets with or without flaxseed. Bacteroidetes, Firmicutes, and Proteobacteria were abundant in both fractions, constituting ...

  8. Pro Access 2010 Development

    CERN Document Server

    Collins, Mark

    2011-01-01

    Pro Access 2010 Development is a fundamental resource for developing business applications that take advantage of the features of Access 2010 and the many sources of data available to your business. In this book, you'll learn how to build database applications, create Web-based databases, develop macros and Visual Basic for Applications (VBA) tools for Access applications, integrate Access with SharePoint and other business systems, and much more. Using a practical, hands-on approach, this book will take you through all the facets of developing Access-based solutions, such as data modeling, co

  9. Access 2013 for dummies

    CERN Document Server

    Ulrich Fuller, Laurie

    2013-01-01

    The easy guide to Microsoft Access returns with updates on the latest version! Microsoft Access allows you to store, organize, view, analyze, and share data; the new Access 2013 release enables you to build even more powerful, custom database solutions that integrate with the web and enterprise data sources. Access 2013 For Dummies covers all the new features of the latest version of Accessand serves as an ideal reference, combining the latest Access features with the basics of building usable databases. You'll learn how to create an app from the Welcome screen, get support

  10. Android Access Control Extension

    Directory of Open Access Journals (Sweden)

    Anton Baláž

    2015-12-01

    Full Text Available The main objective of this work is to analyze and extend security model of mobile devices running on Android OS. Provided security extension is a Linux kernel security module that allows the system administrator to restrict program's capabilities with per-program profiles. Profiles can allow capabilities like network access, raw socket access, and the permission to read, write, or execute files on matching paths. Module supplements the traditional Android capability access control model by providing mandatory access control (MAC based on path. This extension increases security of access to system objects in a device and allows creating security sandboxes per application.

  11. Functional Ecological Gene Networks to Reveal the Changes Among Microbial Interactions Under Elevated Carbon Dioxide Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Ye; Zhou, Jizhong; Luo, Feng; He, Zhili; Tu, Qichao; Zhi, Xiaoyang

    2010-05-17

    Biodiversity and its responses to environmental changes is a central issue in ecology, and for society. Almost all microbial biodiversity researches focus on species richness and abundance but ignore the interactions among different microbial species/populations. However, determining the interactions and their relationships to environmental changes in microbial communities is a grand challenge, primarily due to the lack of information on the network structure among different microbial species/populations. Here, a novel random matrix theory (RMT)-based conceptual framework for identifying functional ecological gene networks (fEGNs) is developed with the high throughput functional gene array hybridization data from the grassland microbial communities in a long-term FACE (Free Air CO2 Enrichment) experiment. Both fEGNs under elevated CO2 (eCO2) and ambient CO2 (aCO2) possessed general characteristics of many complex systems such as scale-free, small-world, modular and hierarchical. However, the topological structure of the fEGNs is distinctly different between eCO2 and aCO2, suggesting that eCO2 dramatically altered the interactions among different microbial functional groups/populations. In addition, the changes in network structure were significantly correlated with soil carbon and nitrogen dynamics, and plant productivity, indicating the potential importance of network interactions in ecosystem functioning. Elucidating network interactions in microbial communities and their responses to environmental changes are fundamentally important for research in microbial ecology, systems microbiology, and global change.

  12. An exogenous surfactant-producing Bacillus subtilis facilitates indigenous microbial enhanced oil recovery

    Directory of Open Access Journals (Sweden)

    Peike eGao

    2016-02-01

    Full Text Available This study used an exogenous lipopeptide-producing Bacillus subtilis to strengthen the indigenous microbial enhanced oil recovery (IMEOR process in a water-flooded reservoir in the laboratory. The microbial processes and driving mechanisms were investigated in terms of the changes in oil properties and the interplay between the exogenous Bacillus subtilis and indigenous microbial populations. The exogenous Bacillus subtilis is a lipopeptide producer, with a short growth cycle and no oil-degrading ability. The Bacillus subtilis facilitates the IMEOR process through improving oil emulsification and accelerating microbial growth with oil as the carbon source. Microbial community studies using quantitative PCR and high-throughput sequencing revealed that the exogenous Bacillus subtilis could live together with reservoir microbial populations, and did not exert an observable inhibitory effect on the indigenous microbial populations during nutrient stimulation. Core-flooding tests showed that the combined exogenous and indigenous microbial flooding increased oil displacement efficiency by 16.71%, compared with 7.59% in the control where only nutrients were added, demonstrating the application potential in enhanced oil recovery in water-flooded reservoirs, in particular, for reservoirs where IMEOR treatment cannot effectively improve oil recovery.

  13. Urban Railway Accessibility

    Institute of Scientific and Technical Information of China (English)

    GUAN Hongzhi; YIN Yuanfei; YAN Hai; HAN Yan; QIN Huanmei

    2007-01-01

    Effective use of urban rapid railway systems requires that the railway systems be effectively connected with other transportation modes so that they are accessible. This paper uses the logit model and data to analyze the factors influencing railway access choices in a railway choice access model. The results indicate that access time, access cost, and access distance are factors significantly affecting railway access choices. The user's income significantly affects the probability of choosing to walk rather than to take a taxi,but is not related to choosing buses or bicycles. Vehicle ownership significantly affects the probability of choosing a taxi, but is not significantly related to the other modes. The conclusions provide an analysis tool for urban railway planning and construction.

  14. Open Access @ DTU

    DEFF Research Database (Denmark)

    Ekstrøm, Jeannette

    Open Access is high on the agenda in Denmark and internationally. Denmark has announced a national strategy for Open Access that aims to achieve Open Access to 80% in 2017 and 100% in 2022 to peer review research articles. All public Danish funders as well as H2020 requires that all peer review...... articles that is an outcome of their funding will be Open Access. Uploading your full texts (your final author manuscript after review ) to DTU Orbit is a fundamental part of providing Open Access to your research. We are here to answer all your questions with regards to Open Access and related topics...... such as copyright, DTU Orbit, Open Access journals, APCs, Vouchers etc....

  15. Petroleum hydrocarbon biodegradation and microbial responses under seasonal freeze-thaw conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chang, W.; Ghoshal, S. [McGill Univ., Montreal, PQ (Canada). Dept. of Civil Engineering and Applied Mechanics; Klemm, S.; Whyte, L. [McGill Univ., Montreal, PQ (Canada). Dept. of Natural Resource Sciences; Simon, P. [Qikiqtaaluk Environmental Inc., Montreal, PQ (Canada)

    2010-07-01

    Seasonal freeze-thaw temperatures influence the metabolic functions of indigenous cold-adapted bacteria. Quantitative assessments of petroleum hydrocarbon biodegradation and microbial community changes under seasonal freeze-thaw temperatures were investigated in this study. Semi- and non-volatile hydrocarbon fractions were measured and microbial community compositions were characterized in a series of controlled biodegradation experiments conducted in a cold room where the seasonal freeze-thaw temperatures of a sub-Arctic site at Resolution Island were simulated. Results of the experiments demonstrated that the seasonal freezing rate did not stop microbial activity. The growth of viable microbial populations was observed in a nutrient-amended soil tank. Microbial respiration was observed during the semi-frozen soil phase where unfrozen water and pore ice co-existed in the soils. Respiration activity was accelerated due to the rapid increases of soil temperature that occurred in early summer. Microbial community shifts were observed during the freezing and thawing phase.

  16. Molecular ecology of microbial mats

    OpenAIRE

    Bolhuis, H; Cretoiu, M.S.; Stal, L.J.

    2014-01-01

    Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep and fluctuating physicochemical microgradients, that are the result of the ever changing environmental conditions and of the microorganisms' own activities, give rise to a plethora of potential ni...

  17. GeoChip as a metagenomics tool to analyze the microbial gene diversity along an elevation gradient

    Directory of Open Access Journals (Sweden)

    Ying Gao

    2014-12-01

    Full Text Available To examine microbial responses to climate change, we used a microarray-based metagenomics tool named GeoChip 4.0 to profile soil microbial functional genes along four sites/elevations of a Tibetan mountainous grassland. We found that microbial communities differed among four elevations. Soil pH, temperature, NH4+–N and vegetation diversity were four major attributes affecting soil microbial communities. Here we describe in details the experiment design, the data normalization process, soil and vegetation analyses associated with the study published on ISME Journal in 2014 [1], whose raw data have been uploaded to Gene Expression Omnibus (accession number GSM1185243.

  18. Microbial diversity in restored wetlands of San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2013-12-09

    Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

  19. Microbial sampling of aluminum-clad spent nuclear fuel

    International Nuclear Information System (INIS)

    A microbial sampling program was initiated at the Idaho National Engineering and Environmental Laboratory (INEEL) to ascertain the effect of microbial activity on the corrosion of aluminum clad spent nuclear fuel (SNF) stored in wet and dry conditions. In the newest fuel storage pool at the INEEL (CPP-666) pitting corrosion has been observed on aluminum corrosion coupons that can not be explained by the excellent water chemistry. Pitting corrosion of the aluminum-clad SNF and corrosion coupons has been observed in the older fuel storage pool (CPP-603). Therefore a microbial assessment of the bulk water, and basin surfaces of both fuel pools was conducted. The results of this microbial enumeration show that a viable and active microbial population does exist in planktonic form. Sampling of aluminum corrosion coupons placed next to stored fuel elements show that microbial attachment has occurred and a biofilm has formed. The sampling program was then extended to the surfaces of wet and dry stored fuel elements. Viable cells or spores were found on the surfaces of the ATR fuel elements that were stored under wet and dry conditions. This paper discusses the methodology of sampling the surfaces of SNF stored under wet conditions for the presence of microorganisms and the types of organisms found

  20. Comparing models of microbial-substrate interactions and their response to warming

    Science.gov (United States)

    Sihi, Debjani; Gerber, Stefan; Inglett, Patrick W.; Sharma Inglett, Kanika

    2016-03-01

    Recent developments in modelling soil organic carbon decomposition include the explicit incorporation of enzyme and microbial dynamics. A characteristic of these models is a positive feedback between substrate and consumers, which is absent in traditional first-order decay models. With sufficiently large substrate, this feedback allows an unconstrained growth of microbial biomass. We explore mechanisms that curb unrestricted microbial growth by including finite potential sites where enzymes can bind and by allowing microbial scavenging for enzymes. We further developed a model where enzyme synthesis is not scaled to microbial biomass but associated with a respiratory cost and microbial population adjusts enzyme production in order to optimise their growth. We then tested short- and long-term responses of these models to a step increase in temperature and find that these models differ in the long-term when short-term responses are harmonised. We show that several mechanisms, including substrate limitation, variable production of microbial enzymes, and microbes feeding on extracellular enzymes eliminate oscillations arising from a positive feedback between microbial biomass and depolymerisation. The model where enzyme production is optimised to yield maximum microbial growth shows the strongest reduction in soil organic carbon in response to warming, and the trajectory of soil carbon largely follows that of a first-order decomposition model. Modifications to separate growth and maintenance respiration generally yield short-term differences, but results converge over time because microbial biomass approaches a quasi-equilibrium with the new conditions of carbon supply and temperature.

  1. Anaerobic fungal populations

    International Nuclear Information System (INIS)

    The development of molecular techniques has greatly broadened our view of microbial diversity and enabled a more complete detection and description of microbial communities. The application of these techniques provides a simple means of following community changes, for example, Ishii et al. described transient and more stable inhabitants in another dynamic microbial system, compost. Our present knowledge of anaerobic gut fungal population diversity within the gastrointestinal tract is based upon isolation, cultivation and observations in vivo. It is likely that there are many species yet to be described, some of which may be non-culturable. We have observed a distinct difference in the ease of cultivation between the different genera, for example, Caecomyes isolates are especially difficult to isolate and maintain in vitro, a feature that is likely to result in the under representation of this genera in culture-based enumerations. The anaerobic gut fungi are the only known obligately anaerobic fungi. For the majority of their life cycles, they are found tightly associated with solid digesta in the rumen and/or hindgut. They produce potent fibrolytic enzymes and grow invasively on and into the plant material they are digesting making them important contributors to fibre digestion. This close association with intestinal digesta has made it difficult to accurately determine the amount of fungal biomass present in the rumen, with Orpin suggesting 8% contribution to the total microbial biomass, whereas Rezaeian et al. more recently gave a value of approximately 20%. It is clear that the rumen microbial complement is affected by dietary changes, and that the fungi are more important in digestion in the rumens of animals fed with high-fibre diets. It seems likely that the gut fungi play an important role within the rumen as primary colonizers of plant fibre, and so we are particularly interested in being able to measure the appearance and diversity of fungi on the plant

  2. Principal methods for isolation and identification of soil microbial communities.

    Science.gov (United States)

    Stefanis, Christos; Alexopoulos, Athanasios; Voidarou, Chrissa; Vavias, Stavros; Bezirtzoglou, Eugenia

    2013-01-01

    Soil microbial populations play crucial role in soil properties and influence below-ground ecosystem processes. Microbial composition and functioning changes the soil quality through decomposition of organic matter, recycling of nutrients, and biological control of parasites of plants. Moreover, the discovery that soil microbes may translate into benefits for biotechnology, management of agricultural, forest, and natural ecosystems, biodegradation of pollutants, and waste treatment systems maximized the need of scientists for the isolation and their characterization. Operations such as the production of antibiotics and enzymic activities from microorganisms of soil constitute objectives of industry in her effort to cope with the increase of population of earth and disturbance of environment and may ameliorate the effects of global climate change. In the past decades, new biochemical and molecular techniques have been developed in our effort to identify and classify soil bacteria. The goal of measuring the soil microbial diversity is difficult because of the limited knowledge about bacteria species and classification through families and orders. Molecular techniques extend our knowledge about microbial diversity and help the taxonomy of species. Measuring and monitoring soil microbial communities can lead us to better understanding of their composition and function in many ecosystem processes. PMID:22791233

  3. Microbial Cell Dynamics Lab (MCDL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Microbial Cell Dynamics Laboratory at PNNL enables scientists to study the molecular details of microbes under relevant environmental conditions. The MCDL seeks...

  4. Creating a safe, high-quality healthcare system for all: meeting the needs of limited English proficient populations; Comment on "Patient safety and healthcare quality: the case for language access".

    Science.gov (United States)

    Betancourt, Joseph R; Tan-McGrory, Aswita

    2014-02-01

    The article by Cheri Wilson, "Patient Safety and Healthcare Quality: The Case for Language Access", highlights the challenges of providing Culturally and Linguistically Appropriate Services (CLAS) to patients with Limited English Proficiency (LEP). As the US pursues high-value, high-performance healthcare, our ability to meet the needs of our most vulnerable will determine whether we succeed or fail in the long run. With the implementation of the Affordable Care Act (ACA), this is more important than ever before, as it is estimated that the newly insured are more likely to be minority and less likely to speak English than their currently insured counterparts. As such, we must create a safe, high-quality healthcare system for all, especially in this time of incredible healthcare transformation and unprecedented diversity. Improving Patient Safety Systems for Patients With Limited English Proficiency: A Guide for Hospitals provides a blueprint for achieving this goal, and Massachusetts General Hospital (MGH) is taking action. PMID:24639984

  5. Halitosis: An oral microbial faction

    Directory of Open Access Journals (Sweden)

    Rajiv Saini

    2010-01-01

    Full Text Available Halitosis is a widespread condition and believed to affect one-quarter of the population around the world; also, most people have this condition from time to time. Breath malodour may be an important factor in social communication, and therefore may be the origin of concern not only for a possible health condition but also for frequent psychological alterations, leading to social and personal isolation. The most conspicuous malodorous compounds are termed volatile sulphur compounds (VSCs, with hydrogen sulphide, methyl mercaptan, and dimethyl sulphide accounting for roughly 90% of the VSCs. A number of oral bacteria, especially Gram-negative anaerobic species found in the subgingival plaque, produce a diverse array of malodorous compounds as byproducts of their metabolism, including VSCs and short-chain organic acids. Assessment and management of halitosis is of paramount importance in enhancing the overall health; moreover, dentists play a significant role in combating halitosis by reducing the oral microbial stack. Thus, the aim of the present review was to describe the aetiological factors, assessment tools, and therapeutic approaches related to halitosis.

  6. Microbial lifestyles that enable survival in lithifying habitats

    Science.gov (United States)

    Hirst, M.; Dossing, L. N.; Tamez, P.; Ziegler, S.; Hanselmann, K.; Sessions, A. L.; Spear, J. R.; Johnson, H.; Berelson, W.; Corsetti, F. A.; Dawson, S.; de la Torre, J. R.; Usc Wrigley Institute, I.

    2010-12-01

    The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone National Park occurs at a rapid rate, whereby microorganisms that colonize the ponds and apron facies are required to overcome lithification. CO2-fixation by autotrophic microorganisms in this cation-rich environment further promotes carbonate encapsulation. Microorganisms that alter their micro-habitat through dissimilative metabolic processes such as H2S and NH4+oxidation, can decrease acid neutralizing capacity (ANCcarb = [HCO3-] + 2[CO32-] + [OH-] - [H+] ) and locally delay CaCO3 mineralization. Genomic and geochemical approaches were combined to study the metabolic processes and microbial populations in a sulfidic hot spring emerging from a carbonate fissure ridge. Samples from locations close to the discharge vent and along its outflow channel were preserved for DNA sequencing, ATP measurements, microscopy, ion chromatographic and ICP-MS analyses of the major solutes and for ANC titration. Temperature, conductivity and pH were measured at the sampling sites. A pyrotagged 16S rRNA gene sequencing approach at both sites was used along with a publicly accessible metagenome of a similar site at the same location. The 16S rRNA gene sequence analyses reveal a great diversity of phylotypes related to species with known physiological potentials. The diversity at the vent is greater and more even than at the cooler site 6m downstream. A number of genes for C-1 fixing enzymes point to the presence of the reductive citric acid cycle, as well as to parts of the reductive acetyl-CoA pathway, the 3-hydroxypropionate cycle and the serine cycle as dominant forms of carbon metabolism. A complete set of genes for all enzymes of the reductive citric acid cycle were found, which indicates a dominance of this pathway for carbon fixation. Surprisingly, genes for RubisCo appear to be absent. Almost all genes found for enzymes that catalyze the conversion of sulfur compounds are involved

  7. Microbial Response to Carbon Dioxide Injection in a Shallow Aquifer

    Science.gov (United States)

    Rook, A.; Faehndrich, D.; O'Mullan, G.; Mailloux, B.; Matter, J.; Stute, M.; Goldberg, D.

    2007-12-01

    Extensive research is underway to investigate the geophysical and geochemical dynamics of subsurface carbon sequestration, but there has been only theoretical consideration of the microbial response. Microbial dynamics are capable of altering the range and rates of geochemical reactions in the subsurface. The goal of this field experiment is to link geochemical changes due to CO2 injection to alterations in the microbial community and to provide an initial characterization of the microbial response. A seven week push-pull experiment was conducted at the Lamont-Doherty Earth Observatory Test Well. 200L of groundwater was extracted, bubbled with carbon dioxide, augmented with a bromide tracer, and injected to 230m depth below ground surface. The hydraulically isolated injection zone marked the contact area between dolerite sill and sedimentary rock. Samples were taken on a weekly basis. Geochemically, a drop in pH from 9.4 to 4.5 at injection was coupled with a release of Fe2+ from the formation. As neutralization and mixing caused pH to return toward background levels, Fe2+ concentrations decreased. The aquifer remained anoxic throughout the experiment. DNA was successfully extracted and the gene encoding 16S ribosomal RNA was amplified from all samples with the exception of the injection fluid. Sequencing from clone libraries and tRFLP analyses were used to characterize microbial dynamics during the seven week study. Whereas the number of microbial groups detected remained relatively constant over the course of the experiment, changes were observed in both the dominant microbes phylogenetic identity and relative abundance. Methane concentrations increased from background levels (below 50 nM) to 4.2 nM after injection, but initial attempts to amplify archaeal and methanogen-specific genes were unsuccessful, bringing into question the presence of a significant methanogenic population. These results confirm that there is a microbial response to carbon dioxide

  8. Sewage Reflects the Microbiomes of Human Populations

    OpenAIRE

    Ryan J Newton; McLellan, Sandra L.; Dila, Deborah K.; Vineis, Joseph H; Morrison, Hilary G; Eren, A. Murat; Sogin, Mitchell L.

    2015-01-01

    ABSTRACT Molecular characterizations of the gut microbiome from individual human stool samples have identified community patterns that correlate with age, disease, diet, and other human characteristics, but resources for marker gene studies that consider microbiome trends among human populations scale with the number of individuals sampled from each population. As an alternative strategy for sampling populations, we examined whether sewage accurately reflects the microbial community of a mixt...

  9. A Conceptual Framework of Mapping Access to Health Care across EU Countries: The Patient Access Initiative.

    Science.gov (United States)

    Souliotis, Kyriakos; Hasardzhiev, Stanimir; Agapidaki, Eirini

    2016-01-01

    Research evidence suggests that access to health care is the key influential factor for improved population health outcomes and health care system sustainability. Although the importance of addressing barriers in access to health care across European countries is well documented, little has been done to improve the situation. This is due to different definitions, approaches and policies, and partly due to persisting disparities in access within and between European countries. To bridge this gap, the Patient Access Partnership (PACT) developed (a) the '5As' definition of access, which details the five critical elements (adequacy, accessibility, affordability, appropriateness, and availability) of access to health care, (b) a multi-stakeholders' approach for mapping access, and (c) a 13-item questionnaire based on the 5As definition in an effort to address these obstacles and to identify best practices. These tools are expected to contribute effectively to addressing access barriers in practice, by suggesting a common framework and facilitating the exchange of knowledge and expertise, in order to improve access to health care between and within European countries. PMID:27237814

  10. EVAPORITE MICROBIAL FILMS, MATS, MICROBIALITES AND STROMATOLITES

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Penny Morris, P; Garriet Smith, G

    2008-01-28

    Evaporitic environments are found in a variety of depositional environments as early as the Archean. The depositional settings, microbial community and mineralogical composition vary significantly as no two settings are identical. The common thread linking all of the settings is that evaporation exceeds precipitation resulting in elevated concentrations of cations and anions that are higher than in oceanic systems. The Dead Sea and Storrs Lake are examples of two diverse modern evaporitic settings as the former is below sea level and the latter is a coastal lake on an island in the Caribbean. Each system varies in water chemistry as the Dead Sea dissolved ions originate from surface weathered materials, springs, and aquifers while Storrs Lake dissolved ion concentration is primarily derived from sea water. Consequently some of the ions, i.e., Sr, Ba are found at significantly lower concentrations in Storrs Lake than in the Dead Sea. The origin of the dissolved ions are ultimately responsible for the pH of each system, alkaline versus mildly acidic. Each system exhibits unique biogeochemical properties as the extreme environments select certain microorganisms. Storrs Lake possesses significant biofilms and stromatolitic deposits and the alkalinity varies depending on rainfall and storm activity. The microbial community Storrs Lake is much more diverse and active than those observed in the Dead Sea. The Dead Sea waters are mildly acidic, lack stromatolites, and possess a lower density of microbial populations. The general absence of microbial and biofilm fossilization is due to the depletion of HCO{sub 3} and slightly acidic pH.

  11. Migrants' access to healthcare

    DEFF Research Database (Denmark)

    Norredam, Marie

    2011-01-01

    There are strong pragmatic and moral reasons for receiving societies to address access to healthcare for migrants. Receiving societies have a pragmatic interest in sustaining migrants' health to facilitate integration; they also have a moral obligation to ensure migrants' access to healthcare...... according to international human rights principles. The intention of this thesis is to increase the understanding of migrants' access to healthcare by exploring two study aims: 1) Are there differences in migrants' access to healthcare compared to that of non-migrants? (substudy I and II); and 2) Why...... are there possible differences in migrants' access to healthcare compared to that of non-migrants? (substudy III and IV). The thesis builds on different methodological approaches using both register-based retrospective cohort design, cross-sectional design and survey methods. Two different measures of access were...

  12. Access Data Analysis Cookbook

    CERN Document Server

    Bluttman, Ken

    2008-01-01

    This book offers practical recipes to solve a variety of common problems that users have with extracting Access data and performing calculations on it. Whether you use Access 2007 or an earlier version, this book will teach you new methods to query data, different ways to move data in and out of Access, how to calculate answers to financial and investment issues, how to jump beyond SQL by manipulating data with VBA, and more.

  13. Usability and accessibility curricula

    OpenAIRE

    Luján Mora, Sergio; Cachero Castro, Cristina

    2012-01-01

    Presentation of existing curricula connected with usability and accessibility at the University of Alicante for the Leonardo da Vinci project "GUI Usability and Accessibility: Exchanging Knowledge and Experiences" (Grenoble, France, 27 November 2012). Presentación del currículo actual relacionado con la usabilidad y la accesibilidad en la Universidad de Alicante para el proyecto Leonardo da Vinci "GUI Usability and Accessibility: Exchanging Knowledge and Experiences" (Grenoble, Francia, 27...

  14. Microbially Mediated Glass Alteration in the Geological Record: Textural clues for Microbial Functions.

    Science.gov (United States)

    Staudigel, H.; Furnes, H.; McLoughlin, N.; Banerjee, N.

    2007-12-01

    Fe and Mn oxidizing microbes interact with their environment through the microbially mediated formation of Fe/Mn oxides and through the corrosion textures they may leave behind in the solids they colonize and from which they extract nutrients. Understanding the geo-biology of Fe and Mn oxidation may focus on the study of the microbes themselves, the mineral products, its biocorrosion features and the relationships between these types of observations. We have reviewed our own data on glass bio-corrosion and in particular the wider literature on microbial mineral tunneling to develop a two stage biocorrosion model for volcanic glass that offers feedback for our understanding of the mechanisms and the dynamics of microbial dissolution. Traces of microbially mediated dissolution of volcanic glass are commonly observed in volcanic glass found in submarine volcanoes on the seafloor, and in uplifted submarine volcanoes of almost any geological age back to the origin of life. Two main bioalteration textures care observed, granular and tubular. Based on a comparison of these features in particular with tunneling by ectomycorrhizal fungi, we propose two distinct types of biocorrosion that affects glass: (1) Granular alteration textures, made up of colonies of microbe-sized, near spherical mineral - filled cavities that form irregular clusters ranging to a tens of micron thick bands at the glas surfaces. These granular textures are interpreted as the result of microbial colonization. accompanied by dissolution of the glass in their contact surface, deposition of authigenic minerals and the formation of a biofilm, that eventually seals the glass from easy access by seawater for hydration, or from microbes accessing Fe (II) in the glass. (2) The most spectacular bioalteration feature, repesented by the formation of tubes cannot be easily formed by the former mechanism because near spherical, individual microbes are likely not to produce the directionality that is required to

  15. Web Accessibility and Guidelines

    Science.gov (United States)

    Harper, Simon; Yesilada, Yeliz

    Access to, and movement around, complex online environments, of which the World Wide Web (Web) is the most popular example, has long been considered an important and major issue in the Web design and usability field. The commonly used slang phrase ‘surfing the Web’ implies rapid and free access, pointing to its importance among designers and users alike. It has also been long established that this potentially complex and difficult access is further complicated, and becomes neither rapid nor free, if the user is disabled. There are millions of people who have disabilities that affect their use of the Web. Web accessibility aims to help these people to perceive, understand, navigate, and interact with, as well as contribute to, the Web, and thereby the society in general. This accessibility is, in part, facilitated by the Web Content Accessibility Guidelines (WCAG) currently moving from version one to two. These guidelines are intended to encourage designers to make sure their sites conform to specifications, and in that conformance enable the assistive technologies of disabled users to better interact with the page content. In this way, it was hoped that accessibility could be supported. While this is in part true, guidelines do not solve all problems and the new WCAG version two guidelines are surrounded by controversy and intrigue. This chapter aims to establish the published literature related to Web accessibility and Web accessibility guidelines, and discuss limitations of the current guidelines and future directions.

  16. OGIS Access System

    Data.gov (United States)

    National Archives and Records Administration — The OGIS Access System (OAS) provides case management, stakeholder collaboration, and public communications activities including a web presence via a web portal.

  17. Microbial bioconversion of pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Golovleva, L.A.; Aliyeva, R.M.; Naumova, R.P.; Gvozdyak, P.I. (Institute of Biochemistry and Physiology of Microorganisms, USSR Academy of Sciences, Moscow (USSR))

    1992-01-01

    Microorganisms totally detoxicate xenobiotics of various chemical structures, which are serious and, in some cases, very hazardous pollutants. At present, the efforts of a number of researchers promoted the establishment in this country of a collection of microorganisms able to degrade volatile toxic pollutants--toluene, isomeric xylenes, styrene, alpha-methylstyrene, crotonaldehyde; widely distributed xenobiotics chlorobenzoic acids; isomeric aryldicarboxylic acids; and ecologically hazardous pollutants such as aromatic nitrocompounds. The active strains-destructors are mainly representatives of the genera Pseudomonas and Rhodococcus. Research into their physiological characteristics, key enzymes, pathways of xenobiotics degradation, genetic mechanisms determining the degradation of these foreign compounds, and behaviour of the strains in a real environment made it possible to develop the theoretical principles of using these microbial cultures to purify real industrial wastes and remediate polluted areas of soil and water. Improvement of the methods of immobilizing the active xenobiotics-degrading strains on cheap and efficient carriers made it possible to significantly intensify the cleanup process of industrial wastes and eliminate a number of problems during the development of the biotechnologies for industrial waste cleanup. Successfully operated at present are the biotechnologies of the local cleanup of waste waters of terephthalate production, microbial purification of industrial waste waters in nylon-66 production from hexamethylenediamine, purification of coke production wastes from phenols, waste waters of polyisocyanate production from aromatic amines, local purification of waste waters in synthetic rubber production from alpha-methylstyrene, acetaldehyde production wastes from crotonaldehyde and mercury. 97 references.

  18. Effect of biodiesel addition on microbial community structure in a simulated fuel storage system.

    Science.gov (United States)

    Restrepo-Flórez, Juan-Manuel; Bassi, Amarjeet; Rehmann, Lars; Thompson, Michael R

    2013-11-01

    Understanding changes in microbial structure due to biodiesel storage is important both for protecting integrity of storage systems and fuel quality management. In this work a simulated storage system was used to study the effect of biodiesel (0%, 25%, 50%, 75% and 100%) on a microbial population, which was followed by community level physiological profiling (CLPP), 16s rDNA analysis and plating in selective media. Results proved that structure and functionality were affected by biodiesel. CLPP showed at least three populations: one corresponding to diesel, one to biodiesel and one to blends of diesel and biodiesel. Analysis of 16s rDNA revealed that microbial composition was different for populations growing in diesel and biodiesel. Genera identified are known for degradation of hydrocarbons and emulsifier production. Maximum growth was obtained in biodiesel; however, microbial counts in standard media were lower for this samples. Acidification of culture media was observed at high biodiesel concentration.

  19. Diversity of human small intestinal Streptococcus and Veillonella populations

    NARCIS (Netherlands)

    Bogert, B. van den; Erkus, O.; Boekhorst, J.; Goffau, M. de; Smid, E.J.; Zoetendal, E.G.; Kleerebezem, M.

    2013-01-01

    Molecular and cultivation approaches were employed to study the phylogenetic richness and temporal dynamics of Streptococcus and Veillonella populations in the small intestine. Microbial profiling of human small intestinal samples collected from four ileostomy subjects at four time points displayed

  20. Microbial ecology of phototrophic biofilms

    NARCIS (Netherlands)

    Roeselers, G.

    2007-01-01

    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic

  1. Microbial interactions during carrion decomposition

    Science.gov (United States)

    This addresses the microbial ecology of carrion decomposition in the age of metagenomics. It describes what is known about the microbial communities on carrion, including a brief synopsis about the communities on other organic matter sources. It provides a description of studies using state-of-the...

  2. Web Resources for Microbial Data

    Institute of Scientific and Technical Information of China (English)

    Qinglan Sun; Li Liu; Linhuan Wu; Wei Li; Quanhe Liu; Jianyuan Zhang; Di Liug; Juncai Ma

    2015-01-01

    There are multitudes of web resources that are quite useful for the microbial scientific research community. Here, we provide a brief introduction on some of the most notable microbial web resources and an evaluation of them based upon our own user experience.

  3. Microbial consortium from nuclear plants show tolerance to biocides

    International Nuclear Information System (INIS)

    Biocides over the last three to four decades have gained in popularity and widespread use in water systems. Industries today routinely incorporate chemical agents into water systems for the purpose of controlling microbial populations. Microorganisms can cause a number of unwanted problems, e.g., fouling, odor, spoilage, corrosion, and health problems in water treatment, manufacturing, food processing, energy production industries. The nuclear industry is no exception to the problems that can be initiated by microbial populations. In some areas the nuclear industry is more susceptible due to the vast number of water systems present and the regulatory limits placed on the water chemistry. Their work has shown that a number of biocides appear to be ineffective in controlling populations that have been isolated from nuclear powerplant water systems

  4. Trichloroethylene degradation by subsurface microbial communities

    International Nuclear Information System (INIS)

    This paper analyzes some of the monitoring data, the effects of methane dosing on methanotrophic populations, and the trichloroethylene (TCE) degradation potentials of the microbial communities from an in situ bioremediation demonstration at the U.S. Department of Energy/Office of Technology Development, Westinghouse Savannah River Site (WSRS). A series of treatments were delivered into a lower horizontal well coupled with vacuum extraction from a vadose zone horizontal well to stimulate TCE-degrading microorganisms. A control phase without treatment was followed by air injection, injection of 1% methane in air, 4% methane in air, pulsed methane and air injection, and continuous addition of triethyl phosphate and nitrous oxide in air with pulsed additions of methane and air. Microbial monitoring was utilized to demonstrate the effectiveness of bioremediation and to optimize the treatment regimes and continued for a few months after termination of all treatments. Examination of the methane present in specific wells indicated that methanotrophic populations responded to methane delivery, whereas TCE degradation capacity was not as directly tied to the methane availability. Other factors such as nitrate and phosphate availability apparently played a crucial role in the TCE degradation activity

  5. Understanding Bacteriophage Specificity in Natural Microbial Communities

    Directory of Open Access Journals (Sweden)

    Britt Koskella

    2013-03-01

    Full Text Available Studying the coevolutionary dynamics between bacteria and the bacteriophage viruses that infect them is critical to understanding both microbial diversity and ecosystem functioning. Phages can play a key role in shaping bacterial population dynamics and can significantly alter both intra- and inter-specific competition among bacterial hosts. Predicting how phages might influence community stability and apparent competition, however, requires an understanding of how bacteria-phage interaction networks evolve as a function of host diversity and community dynamics. Here, we first review the progress that has been made in understanding phage specificity, including the use of experimental evolution, we then introduce a new dataset on natural bacteriophages collected from the phyllosphere of horse chestnut trees, and finally we highlight that bacterial sensitivity to phage is rarely a binary trait and that this variation should be taken into account and reported. We emphasize that there is currently insufficient evidence to make broad generalizations about phage host range in natural populations, the limits of phage adaptation to novel hosts, or the implications of phage specificity in shaping microbial communities. However, the combination of experimental and genomic approaches with the study of natural communities will allow new insight to the evolution and impact of phage specificity within complex bacterial communities.

  6. The pig gut microbial diversity: Understanding the pig gut microbial ecology through the next generation high throughput sequencing.

    Science.gov (United States)

    Kim, Hyeun Bum; Isaacson, Richard E

    2015-06-12

    The importance of the gut microbiota of animals is widely acknowledged because of its pivotal roles in the health and well being of animals. The genetic diversity of the gut microbiota contributes to the overall development and metabolic needs of the animal, and provides the host with many beneficial functions including production of volatile fatty acids, re-cycling of bile salts, production of vitamin K, cellulose digestion, and development of immune system. Thus the intestinal microbiota of animals has been the subject of study for many decades. Although most of the older studies have used culture dependent methods, the recent advent of high throughput sequencing of 16S rRNA genes has facilitated in depth studies exploring microbial populations and their dynamics in the animal gut. These culture independent DNA based studies generate large amounts of data and as a result contribute to a more detailed understanding of the microbiota dynamics in the gut and the ecology of the microbial populations. Of equal importance, is being able to identify and quantify microbes that are difficult to grow or that have not been grown in the laboratory. Interpreting the data obtained from this type of study requires using basic principles of microbial diversity to understand importance of the composition of microbial populations. In this review, we summarize the literature on culture independent studies of the pig gut microbiota with an emphasis on its succession and alterations caused by diverse factors. PMID:25843944

  7. 我国城乡公共体育服务均等化发展策略研究——基于农村人口流动与迁移角度%Equal access to public service in urban and rural areas in China sports development strategy ——Based on the rural population flow and migration angle

    Institute of Scientific and Technical Information of China (English)

    李详; 周武

    2012-01-01

    我国经济发展尚未到达“刘易斯转折点”,农村外出务工人员仍将继续向城市流动,而且呈增长趋势;我国城市化发展已由原来的“自上而下”政府管制模式转变为“自下而上”市场经济主导模式,市场经济继续推动我国农村人口城市化发展。农村人口的继续流动和迁移将对输入地、输出地和流动迁移人群自身的公共体育服务均等化发展造成不利的影响。鉴于对我国农村人口流动的现状和未来迁移趋势考虑,我国城乡公共体育服务均等化发展战略应将重点放在城市中农民工、农村留守人群、小城镇和社会主义新农村公共体育服务均等化建设上。%The economic development of China has not reached " Lewis turning point," rural migrant workers still continue to flow to the city with a growing trend; The urbanization development has the original " top - down" government control model into a " bottom - up" market economy the dominant model, the market economy continued to promoting China~ rural population urbanization development. Rural population migration will continue to flow and to input fields, output and migration of people own public sports service to cause adverse effects of the equal access to the development. Therefore, in view of China's rural population flow to the present and future trend of migration considerations, China's urban and rural public sports service development strategy should be equal access to focus on rural migrant workers in cities, rural rear crowd, small towns and socialist new countryside public sports on the building of the equal access to the service.

  8. Evolution in an Afternoon: Rapid Natural Selection and Adaptation of Bacterial Populations

    Science.gov (United States)

    Delpech, Roger

    2009-01-01

    This paper describes a simple, rapid and low-cost technique for growing bacteria (or other microbes) in an environmental gradient, in order to determine the tolerance of the microbial population to varying concentrations of sodium chloride ions, and suggests how the evolutionary response of a microbial population to the selection pressure of the…

  9. Coded Random Access

    DEFF Research Database (Denmark)

    Paolini, Enrico; Stefanovic, Cedomir; Liva, Gianluigi;

    2015-01-01

    as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access...

  10. Market Access and Welfare

    DEFF Research Database (Denmark)

    Raimondos-Møller, Pascalis; Woodland, Alan D.

    2015-01-01

    Well known tariff reform rules that are guaranteed to increase welfare will not necessarily increase market access, while rules that are guaranteed to increase market access will not necessarily increase welfare. The present paper proposes a new set of tariff reforms that can achieve both...

  11. Intellectual Access to Images.

    Science.gov (United States)

    Chen, Hsin-Liang; Rasmussen, Edie M.

    1999-01-01

    The increased availability of digital images is accompanied by a need for solutions to the problems inherent in indexing them for retrieval. Problems in image description and access are discussed, with a perspective on traditional and new solutions. Recent developments in intellectual access to images are surveyed and contrasted with…

  12. Financing low carbon energy access in Africa

    International Nuclear Information System (INIS)

    Modern energy access in Africa is critical to meeting a wide range of developmental challenges including poverty reduction and the Millennium Development Goals (MDGs). Despite having a huge amount and variety of energy resources, modern energy access in the continent is abysmal, especially Sub-Saharan Africa. Only about 31% of the Sub-Saharan African population have access to electricity while traditional biomass energy accounts for over 80% of energy consumption in many Sub-Saharan African countries. With energy use per capita among the lowest in the world, there is no doubt that Africa will need to increase its energy consumption to drive economic growth and human development. Africa also faces a severe threat from global climate change with vulnerabilities in several key areas or sectors in the continent including agriculture, water supply, energy, etc. Low carbon development provides opportunities for African countries to improve and expand access to modern energy services while also building low-emission and climate-resilient economies. However, access to finance from different sources will be critical in achieving these objectives. This paper sets out to explore the financial instruments available for low carbon energy access in Africa including the opportunities, markets and risks in low carbon energy investments in the continent. - Highlights: ► Access to finance will be critical to achieving low carbon energy access in Africa. ► Domestic finance will be important in leveraging private finance. ► Private sector participation in modern and clean energy in Africa is still low. ► Many financing mechanisms exist for low carbon energy access in Africa. ► The right institutional frameworks are critical to achieving low carbon energy access in Africa.

  13. Os Centros de Testagem e Aconselhamento (CTA no município do Rio de Janeiro e o acesso ao diagnóstico do HIV entre e população negra: uma análise qualitativa Testing and Counseling Centers (TCC in Rio de Janeiro city, and access to the HIV diagnosis for the black population: a qualitative analysis

    Directory of Open Access Journals (Sweden)

    Carla Luzia França Araújo

    2010-12-01

    and reflect social inequality. This research aims at discussing the black population's access to the HIV diagnosis in Rio de Janeiro city. The qualitative method was chosen. Data were collected through 62 semi-structured interviews with people who declared themselves black or mulatto and visited the Testing and Counseling Center (TCC to take the HIV test. Data analysis was based on the premises of the Collective Subject Discourse. Most interviewees did not report any difficulties to get access to the HIV test. The repressed demand at the TCC was identified as a barrier, due to the limited test offer caused by material and human resource issues. No statement was found that demonstrated color/race discrimination during contact with the service. Factors appointed as facilitating test access included: free test, indication or referral by health professionals or service, access to the test site, service credibility, rapid care and absence of bureaucracy.

  14. Mechanism of acetaldehyde-induced deactivation of microbial lipases

    Directory of Open Access Journals (Sweden)

    Jaeger Karl E

    2011-02-01

    Full Text Available Abstract Background Microbial lipases represent the most important class of biocatalysts used for a wealth of applications in organic synthesis. An often applied reaction is the lipase-catalyzed transesterification of vinyl esters and alcohols resulting in the formation of acetaldehyde which is known to deactivate microbial lipases, presumably by structural changes caused by initial Schiff-base formation at solvent accessible lysine residues. Previous studies showed that several lipases were sensitive toward acetaldehyde deactivation whereas others were insensitive; however, a general explanation of the acetaldehyde-induced inactivation mechanism is missing. Results Based on five microbial lipases from Candida rugosa, Rhizopus oryzae, Pseudomonas fluorescens and Bacillus subtilis we demonstrate that the protonation state of lysine ε-amino groups is decisive for their sensitivity toward acetaldehyde. Analysis of the diverse modification products of Bacillus subtilis lipases in the presence of acetaldehyde revealed several stable products such as α,β-unsaturated polyenals, which result from base and/or amino acid catalyzed aldol condensation of acetaldehyde. Our studies indicate that these products induce the formation of stable Michael-adducts at solvent-accessible amino acids and thus lead to enzyme deactivation. Further, our results indicate Schiff-base formation with acetaldehyde to be involved in crosslinking of lipase molecules. Conclusions Differences in stability observed with various commercially available microbial lipases most probably result from different purification procedures carried out by the respective manufacturers. We observed that the pH of the buffer used prior to lyophilization of the enzyme sample is of utmost importance. The mechanism of acetaldehyde-induced deactivation of microbial lipases involves the generation of α,β-unsaturated polyenals from acetaldehyde which subsequently form stable Michael-adducts with the

  15. Dynamics of microbial growth and coexistence on variably saturated rough surfaces.

    Science.gov (United States)

    Long, Tao; Or, Dani

    2009-08-01

    The high degree of microbial diversity found in soils is attributed to the highly heterogeneous pore space and the dynamic aqueous microenvironments. Previous studies have shown that spatial and temporal variations in aqueous diffusion pathways play an important role in shaping microbial habitats and biological activity in unsaturated porous media. A new modeling framework was developed for the quantitative description of diffusion-dominated microbial interactions focusing on competitive growth of two microbial species inhabiting partially saturated rough surfaces. Surface heterogeneity was represented by patches with different porosities and water retention properties, yielding heterogeneous distribution of water contents that varies with changes in relative humidity or soil matric potential. Nutrient diffusion and microbial growth on the variably hydrated and heterogeneous surface was modeled using a hybrid method that combines a reaction diffusion method for nutrient field with individual based model for microbial growth and expansion. The model elucidated the effects of hydration dynamics and heterogeneity on nutrient fluxes and mobility affecting microbial population growth, expansion, and coexistence at the microscale. In contrast with single species dominance under wet conditions, results demonstrated prolonged coexistence of two competing species under drier conditions where nutrient diffusion and microbial movement were both limited. The uneven distribution of resources and diffusion pathways in heterogeneous surfaces highlighted the importance of position in the landscape for survival that may compensate for competitive disadvantages conferred by physiological traits. Increased motility was beneficial for expansion and survival. Temporal variations in hydration conditions resulted in fluctuations in microbial growth rate and population size. Population growth dynamics of the dominant species under wet-dry cycles were similar to growth under average value

  16. Microbial "social networks"

    Science.gov (United States)

    2015-01-01

    Background It is well understood that distinct communities of bacteria are present at different sites of the body, and that changes in the structure of these communities have strong implications for human health. Yet, challenges remain in understanding the complex interconnections between the bacterial taxa within these microbial communities and how they change during the progression of diseases. Many recent studies attempt to analyze the human microbiome using traditional ecological measures and cataloging differences in bacterial community membership. In this paper, we show how to push metagenomic analyses beyond mundane questions related to the bacterial taxonomic profiles that differentiate one sample from another. Methods We develop tools and techniques that help us to investigate the nature of social interactions in microbial communities, and demonstrate ways of compactly capturing extensive information about these networks and visually conveying them in an effective manner. We define the concept of bacterial "social clubs", which are groups of taxa that tend to appear together in many samples. More importantly, we define the concept of "rival clubs", entire groups that tend to avoid occurring together in many samples. We show how to efficiently compute social clubs and rival clubs and demonstrate their utility with the help of examples including a smokers' dataset and a dataset from the Human Microbiome Project (HMP). Results The tools developed provide a framework for analyzing relationships between bacterial taxa modeled as bacterial co-occurrence networks. The computational techniques also provide a framework for identifying clubs and rival clubs and for studying differences in the microbiomes (and their interactions) of two or more collections of samples. Conclusions Microbial relationships are similar to those found in social networks. In this work, we assume that strong (positive or negative) tendencies to co-occur or co-infect is likely to have

  17. The Open Access Divide

    Directory of Open Access Journals (Sweden)

    Jingfeng Xia

    2013-10-01

    Full Text Available This paper is an attempt to review various aspects of the open access divide regarding the difference between those academics who support free sharing of data and scholarly output and those academics who do not. It provides a structured description by adopting the Ws doctrines emphasizing such questions as who, what, when, where and why for information-gathering. Using measurable variables to define a common expression of the open access divide, this study collects aggregated data from existing open access as well as non-open access publications including journal articles and extensive reports. The definition of the open access divide is integrated into the discussion of scholarship on a larger scale.

  18. 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

    The report presents data on microbial O{sub 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{sub 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{sub 2} reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O{sub 2} reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O{sub 2} reduction confirming the biogenic nature of the reduction. The populations developed O{sub 2} reduction rates and capacity depending on the initial concentration of dissolved O{sub 2} reduction. Rates of O{sub 2} reduction ranged from 0.32 to 4.5 {mu}M/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 {mu}M of dissolved O{sub 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{sub 2} both at 30 deg C and 60 deg C. At 16 deg C no delay in O{sub 2} consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O{sub 2}. Some bacteria use Hg or CH{sub 4} as electron donor instead of organic matter, which means that microbial O{sub 2} reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH{sub 4} oxidation rates ranged between 3.00 and 220 nM CH{sub 4} per litre per

  19. Microbial communities responsible for corrosion and souring in oil fields

    Energy Technology Data Exchange (ETDEWEB)

    Voordouw, G. [Calgary Univ., AB (Canada). Dept. of Biological Sciences; Jack, T.R. [Novacor Research and Technology Corp., Calgary, AB (Canada); Foght, J.M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biochemistry

    1996-05-01

    Oil field microbial communities and their role in in situ hydrocarbon degradation, oil desulfurization, souring and metal corrosion were discussed. Focus was on molecular biological methods to characterize microbial communities found in oil fields in Western Canada that have moderate resident temperatures. DNA was isolated from samples of different oil fields and was analyzed. It was found that populations differed depending on salinity of oil field production waters. At least 24 different sulfate reducing bacteria (SRB), three different fermentative bacteria and six different sulfide oxidizers and microaerophiles were found to be present in oil field production waters. This indicated that sulfate may be the most important electron acceptor in the oil field microbial community. 10 refs., 1 tab., 6 figs.

  20. Microbial O2 consumption in the Aespoe tunnel

    International Nuclear Information System (INIS)

    The report presents data on microbial O2 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 O2 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 O2 reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O2 reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O2 reduction confirming the biogenic nature of the reduction. The populations developed O2 reduction rates and capacity depending on the initial concentration of dissolved O2 reduction. Rates of O2 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 O2 ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O2 both at 30 deg C and 60 deg C. At 16 deg C no delay in O2 consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O2. Some bacteria use Hg or CH4 as electron donor instead of organic matter, which means that microbial O2 reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH4 oxidation rates ranged between 3.00 and 220 nM CH4 per litre per day. Comparison of the total O2 reducing activities by gas chromatography and radiotracer tests