WorldWideScience

Sample records for microbial growth determination

  1. Determination of Nitrate Reductase Assay Depending on the Microbial Growth

    International Nuclear Information System (INIS)

    El-Kabbany, H.M.

    2012-01-01

    A rapid micro-dilution assay for determination of the antimicrobial susceptibility of different bacterial isolates was developed. This assay is based on the ability of the most of viable organisms to reduce nitrates. The MIC or MBC could be determined by nitrate reductase (NR) only after 30 to 90 min of incubation depending on the behaviour of microbial growth. Bacterial viability is detected by a positive nitrite reduction rather than visible turbidity. The nitrate reduction assay was compared with standard micro-assay using 250 isolates of different taxa against 10 antibiotics belonging to different classes. An excellent agreement of 82.5 % was found between the two methods and only 17.5 % of 1794 trials showed difference in the determined MIC by tow-dilution interval above or below the MIC determined by the turbidimetric method under the same test conditions. However, the nitrate reduction assay was more rapid and sensitive in detecting viable bacteria and so, established an accurate estimate of the minimal inhibitory concentration (MIC) or the minimal bacterial concentration (MBC). The nitrate reduction assay offers the additional advantage that it could be used to determine the MBC without having to subculture the broth. 232 cases of resistance were detected by NR and 4 different media were tested for susceptibility test. The bacterial isolates were exposed to ultra violet (UV) light for different period

  2. Determination of rumen microbial growth in vitro form 32P-labelled phosphate incorporation

    International Nuclear Information System (INIS)

    Nevel, C.J. Van; Demeyer, D.I.

    1977-01-01

    The extracellular phosphate pool in incubations of rumen fluid or washed cell suspensions of mixed rumen bacteria (WCS) was labelled with 32 P. From the constant extracellular phosphate pool specific activity and the amount of radioactivity incorporated during incubation, the amount of P incorporated in the microbial fraction was calculated. From the value for nitrogen: P determined in microbial matter, the amount of N incorporated was calculated as a measure of microbial growth. Incorporation of soluble non-protein-N in incubations devoid of substrate protein was 50 and 80% of the values obtained using isotope method for rumen fluid and WCS respectively. Incorporation of 32 P in P-containing microbial components (mainly nucleic acids) was compared with net synthesis of these components in incubations of WCS. When N incorporation, calculated from results obtained using isotope method in incubations with rumen fluid, was compared with the amount of carbohydrate substrate fermented and the type of fermentation, values between 18.3 and 44.6 g N incorporated kg of organic matter fermented were obtained. The use of isotopes for determination of rumen microbial growth in vitro is critically discussed. (author)

  3. Using growth-based methods to determine direct effects of salinity on soil microbial communities

    Science.gov (United States)

    Rath, Kristin; Rousk, Johannes

    2015-04-01

    Soil salinization is a widespread agricultural problem and increasing salt concentrations in soils have been found to be correlated with decreased microbial activity. A central challenge in microbial ecology is to link environmental factors, such as salinity, to responses in the soil microbial community. That is, it can be difficult to distinguish direct from indirect effects. In order to determine direct salinity effects on the community we employed the ecotoxicological concept of Pollution-Induced Community Tolerance (PICT). This concept is built on the assumption that if salinity had an ecologically relevant effect on the community, it should have selected for more tolerant species and strains, resulting in an overall higher community tolerance to salt in communities from saline soils. Growth-based measures, such as the 3H-leucine incorporation into bacterial protein , provide sensitive tools to estimate community tolerance. They can also provide high temporal resolution in tracking changes in tolerance over time. In our study we used growth-based methods to investigate: i) at what levels of salt exposure and over which time scales salt tolerance can be induced in a non-saline soil, and (ii) if communities from high salinity sites have higher tolerance to salt exposure along natural salinity gradients. In the first part of the study, we exposed a non-saline soil to a range of salinities and monitored the development of community tolerance over time. We found that community tolerance to intermediate salinities up to around 30 mg NaCl per g soil can be induced at relatively short time scales of a few days, providing evidence that microbial communities can adapt rapidly to changes in environmental conditions. In the second part of the study we used soil samples originating from natural salinity gradients encompassing a wide range of salinity levels, with electrical conductivities ranging from 0.1 dS/m to >10 dS/m. We assessed community tolerance to salt by

  4. New microbial growth factor

    Science.gov (United States)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  5. Growth Mechanism of Microbial Colonies

    Science.gov (United States)

    Zhu, Minhui; Martini, K. Michael; Kim, Neil H.; Sherer, Nicholas; Lee, Jia Gloria; Kuhlman, Thomas; Goldenfeld, Nigel

    Experiments on nutrient-limited E. coli colonies, growing on agar gel from single cells reveal a power-law distribution of sizes, both during the growth process and in the final stage when growth has ceased. We developed a Python simulation to study the growth mechanism of the bacterial population and thus understand the broad details of the experimental findings. The simulation takes into account nutrient uptake, metabolic function, growth and cell division. Bacteria are modeled in two dimensions as hard circle-capped cylinders with steric interactions and elastic stress dependent growth characteristics. Nutrient is able to diffuse within and between the colonies. The mechanism of microbial colony growth involves reproduction of cells within the colonies and the merging of different colonies. We report results on the dynamic scaling laws and final state size distribution, that capture in semi-quantitative detail the trends observed in experiment. Supported by NSF Grant 0822613.

  6. 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.

  7. Conditioning biomass for microbial growth

    Science.gov (United States)

    Bodie, Elizabeth A; England, George

    2015-03-31

    The present invention relates to methods for improving the yield of microbial processes that use lignocellulose biomass as a nutrient source. The methods comprise conditioning a composition comprising lignocellulose biomass with an enzyme composition that comprises a phenol oxidizing enzyme. The conditioned composition can support a higher rate of growth of microorganisms in a process. In one embodiment, a laccase composition is used to condition lignocellulose biomass derived from non-woody plants, such as corn and sugar cane. The invention also encompasses methods for culturing microorganisms that are sensitive to inhibitory compounds in lignocellulose biomass. The invention further provides methods of making a product by culturing the production microorganisms in conditioned lignocellulose biomass.

  8. Microbial growth and substrate utilization kinetics | Okpokwasili ...

    African Journals Online (AJOL)

    Microbial growth on and utilization of environmental contaminants as substrates have been studied by many researchers. Most times, substrate utilization results in removal of chemical contaminant, increase in microbial biomass and subsequent biodegradation of the contaminant. These are all aimed at detoxification of the ...

  9. Mechanistic model for microbial growth on hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Mallee, F M; Blanch, H W

    1977-12-01

    Based on available information describing the transport and consumption of insoluble alkanes, a mechanistic model is proposed for microbial growth on hydrocarbons. The model describes the atypical growth kinetics observed, and has implications in the design of large scale equipment for single cell protein (SCP) manufacture from hydrocarbons. The model presents a framework for comparison of the previously published experimental kinetic data.

  10. 21 CFR 866.2560 - Microbial growth monitor.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2560 Microbial growth monitor. (a) Identification. A microbial growth monitor is a device intended for medical purposes that...

  11. Robust Growth Determinants

    OpenAIRE

    Doppelhofer, Gernot; Weeks, Melvyn

    2011-01-01

    This paper investigates the robustness of determinants of economic growth in the presence of model uncertainty, parameter heterogeneity and outliers. The robust model averaging approach introduced in the paper uses a flexible and parsi- monious mixture modeling that allows for fat-tailed errors compared to the normal benchmark case. Applying robust model averaging to growth determinants, the paper finds that eight out of eighteen variables found to be significantly related to economic growth ...

  12. Hydrocarbon fermentation: kinetics of microbial cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Goma, G [Institut National des Sciences Appliquees, Toulouse; Ribot, D

    1978-11-01

    Modeling of microbial growth using nonmiscible substrate is studied when kinetics of substrate dissolution is rate limiting. When the substrate concentration is low, the growth rate is described by an analytical relation that can be identified as a Contois relationship. If the substrate concentration is greater than a critical value S/sub crit/, the potentially useful hydrocarbon S* concentration is described by S* = S/sub crit//(1 + S/sub crit//S). A relationship was found between S/sub crit/ and the biomass concentration X. When X increased, S/sub crit/ decreased. The cell growth rate is related to a relation ..mu.. = ..mu../sub m/(A(X/S/sub crit/)(1 + S/sub crit//S) + 1)/sup -1/. This model describes the evolution of the growth rate when exponential or linear growth occurs, which is related to physico-chemical properties and hydrodynamic fermentation conditions. Experimental data to support the model are presented.

  13. Susceptibility of green and conventional building materials to microbial growth.

    Science.gov (United States)

    Mensah-Attipoe, J; Reponen, T; Salmela, A; Veijalainen, A-M; Pasanen, P

    2015-06-01

    Green building materials are becoming more popular. However, little is known about their ability to support or limit microbial growth. The growth of fungi was evaluated on five building materials. Two green, two conventional building materials and wood as a positive control were selected. The materials were inoculated with Aspergillus versicolor, Cladosporium cladosporioides and Penicillium brevicompactum, in the absence and presence of house dust. Microbial growth was assessed at four different time points by cultivation and determining fungal biomass using the N-acetylhexosaminidase (NAHA) enzyme assay. No clear differences were seen between green and conventional building materials in their susceptibility to support microbial growth. The presence of dust, an external source of nutrients, promoted growth of all the fungal species similarly on green and conventional materials. The results also showed a correlation coefficient ranging from 0.81 to 0.88 between NAHA activity and culturable counts. The results suggest that the growth of microbes on a material surface depends on the availability of organic matter rather than the classification of the material as green or conventional. NAHA activity and culturability correlated well indicating that the two methods used in the experiments gave similar trends for the growth of fungi on material surfaces. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Impact of warm winters on microbial growth

    Science.gov (United States)

    Birgander, Johanna; Rousk, Johannes; Axel Olsson, Pål

    2014-05-01

    Growth of soil bacteria has an asymmetrical response to higher temperature with a gradual increase with increasing temperatures until an optimum after which a steep decline occurs. In laboratory studies it has been shown that by exposing a soil bacterial community to a temperature above the community's optimum temperature for two months, the bacterial community grows warm-adapted, and the optimum temperature of bacterial growth shifts towards higher temperatures. This result suggests a change in the intrinsic temperature dependence of bacterial growth, as temperature influenced the bacterial growth even though all other factors were kept constant. An intrinsic temperature dependence could be explained by either a change in the bacterial community composition, exchanging less tolerant bacteria towards more tolerant ones, or it could be due to adaptation within the bacteria present. No matter what the shift in temperature tolerance is due to, the shift could have ecosystem scale implications, as winters in northern Europe are getting warmer. To address the question of how microbes and plants are affected by warmer winters, a winter-warming experiment was established in a South Swedish grassland. Results suggest a positive response in microbial growth rate in plots where winter soil temperatures were around 6 °C above ambient. Both bacterial and fungal growth (leucine incorporation, and acetate into ergosterol incorporation, respectively) appeared stimulated, and there are two candidate explanations for these results. Either (i) warming directly influence microbial communities by modulating their temperature adaptation, or (ii) warming indirectly affected the microbial communities via temperature induced changes in bacterial growth conditions. The first explanation is in accordance with what has been shown in laboratory conditions (explained above), where the differences in the intrinsic temperature relationships were examined. To test this explanation the

  15. Rumen microbial growth estimation using in vitro radiophosphorous incorporation technique

    International Nuclear Information System (INIS)

    Bueno, Ives Claudio da Silva; Machado, Mariana de Carvalho; Cabral Filho, Sergio Lucio Salomon; Gobbo, Sarita Priscila; Vitti, Dorinha Miriam Silber Schmidt; Abdalla, Adibe Luiz

    2002-01-01

    Rumen microorganisms are able to transform low biological value nitrogen of feed stuff into high quality protein. To determine how much microbial protein that process forms, radiomarkers can be used. Radiophosphorous has been used to mark microbial protein, as element P is present in all rumen microorganisms (as phospholipids) and the P:N ratio of rumen biomass is quite constant. The aim of this work was to estimate microbial synthesis from feedstuff commonly used in ruminant nutrition in Brazil. Tested feeds were fresh alfalfa, raw sugarcane bagasse, rice hulls, rice meal, soybean meal, wheat meal, Tifton hay, leucaena, dehydrated citrus pulp, wet brewers' grains and cottonseed meal. 32 P-labelled phosphate solution was used as marker for microbial protein. Results showed the diversity of feeds by distinct quantities of nitrogen incorporated into microbial mass. Low nutrient availability feeds (sugarcane bagasse and rice hulls) promoted the lowest values of incorporated nitrogen. Nitrogen incorporation showed positive relationship (r=0.56; P=0.06) with the rate of degradation and negative relationship (r=-0.59; P<0.05) with fiber content of feeds. The results highlight that easier fermentable feeds (higher rates of degradation) and/or with lower fiber contents promote a more efficient microbial growth and better performance for the host animal. (author)

  16. Rumen microbial growth estimation using in vitro radiophosphorous incorporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Ives Claudio da Silva; Machado, Mariana de Carvalho; Cabral Filho, Sergio Lucio Salomon; Gobbo, Sarita Priscila; Vitti, Dorinha Miriam Silber Schmidt; Abdalla, Adibe Luiz [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    2002-07-01

    Rumen microorganisms are able to transform low biological value nitrogen of feed stuff into high quality protein. To determine how much microbial protein that process forms, radiomarkers can be used. Radiophosphorous has been used to mark microbial protein, as element P is present in all rumen microorganisms (as phospholipids) and the P:N ratio of rumen biomass is quite constant. The aim of this work was to estimate microbial synthesis from feedstuff commonly used in ruminant nutrition in Brazil. Tested feeds were fresh alfalfa, raw sugarcane bagasse, rice hulls, rice meal, soybean meal, wheat meal, Tifton hay, leucaena, dehydrated citrus pulp, wet brewers' grains and cottonseed meal. {sup 32} P-labelled phosphate solution was used as marker for microbial protein. Results showed the diversity of feeds by distinct quantities of nitrogen incorporated into microbial mass. Low nutrient availability feeds (sugarcane bagasse and rice hulls) promoted the lowest values of incorporated nitrogen. Nitrogen incorporation showed positive relationship (r=0.56; P=0.06) with the rate of degradation and negative relationship (r=-0.59; P<0.05) with fiber content of feeds. The results highlight that easier fermentable feeds (higher rates of degradation) and/or with lower fiber contents promote a more efficient microbial growth and better performance for the host animal. (author)

  17. Microbial growth on C1 compounds: proceedings

    International Nuclear Information System (INIS)

    Crawford, R.L.; Hanson, R.S.

    1984-01-01

    This book contains individual papers prepared for the 4th International Symposium on Microbial Growth on One Carbon Compounds. Individual reports were abstracted and indexed for EDB. Topics presented were in the areas of the physiology and biochemistry of autotraps, physiology and biochemistry of methylotrophs and methanotrops, physiology and biochemistry of methanogens, genetics of microbes that use C 1 compounds, taxonomy and ecology of microbes tht grow on C 1 compounds, applied aspects of microbes that grow on C 1 compounds, and new directions in C 1 metabolism. (DT)

  18. Accounting for inherent variability of growth in microbial risk assessment.

    Science.gov (United States)

    Marks, H M; Coleman, M E

    2005-04-15

    Risk assessments of pathogens need to account for the growth of small number of cells under varying conditions. In order to determine the possible risks that occur when there are small numbers of cells, stochastic models of growth are needed that would capture the distribution of the number of cells over replicate trials of the same scenario or environmental conditions. This paper provides a simple stochastic growth model, accounting only for inherent cell-growth variability, assuming constant growth kinetic parameters, for an initial, small, numbers of cells assumed to be transforming from a stationary to an exponential phase. Two, basic, microbial sets of assumptions are considered: serial, where it is assume that cells transform through a lag phase before entering the exponential phase of growth; and parallel, where it is assumed that lag and exponential phases develop in parallel. The model is based on, first determining the distribution of the time when growth commences, and then modelling the conditional distribution of the number of cells. For the latter distribution, it is found that a Weibull distribution provides a simple approximation to the conditional distribution of the relative growth, so that the model developed in this paper can be easily implemented in risk assessments using commercial software packages.

  19. Spectrum of microbial growth and antimicrobial usage in an ...

    African Journals Online (AJOL)

    white blood cell count, duration of first antibiotic used, length of ICU stay, length of ... the acute disease process, the presence of comorbidities, invasive devices, ... Against this background, this study aimed to look at the microbial growth.

  20. Spatial & Temporal Geophysical Monitoring of Microbial Growth and Biofilm Formation

    Science.gov (United States)

    Previous studies have examined the effect of biogenic gases and biomineralization on the acoustic properties of porous media. In this study, we investigated the spatiotemporal effect of microbial growth and biofilm formation on compressional waves and complex conductivity in sand...

  1. DETERMINANTS OF ECONOMIC GROWTH

    OpenAIRE

    Bartosz Totleben

    2013-01-01

    The article is examines the impact of macroeconomic indicators, in particular: human capital, government spending, innovation, political and social stability, on economic growth. In total 12 different indicators describing the economical, political and social conditions are taken into account. The study considers 102 countries between years 1960 and 2012 and two methods of estimation are performed: generalized method of moments (GMM) and fixed effects (FE). The results show the positive impac...

  2. Determination of microbial protein in perennial ryegrass silage

    NARCIS (Netherlands)

    Driehuis, F.; Wikselaar, van P.G.

    2001-01-01

    The microbial matter fraction was determined in perennial ryegrass silages of different dry-matter (DM) contents, ensiled with or without Lactobacillus plantarum. 15N-Leucine and the bacterial cell wall constituent diaminopimelic acid (DAPA) were used as markers for microbial-N. Perennial ryegrass

  3. Acoustic and Electrical Property Changes Due to Microbial Growth and Biofilm Formation in Porous Media

    Science.gov (United States)

    A laboratory study was conducted to investigate the effect of microbial growth and biofilm formation on compressional waves, and complex conductivity during stimulated microbial growth. Over the 29 day duration of the experiment, compressional wave amplitudes and arrival times f...

  4. Conditions for microbial growth in the FILTRA steam absorption tower

    International Nuclear Information System (INIS)

    Nilsson, H.; Roffey, R.

    1983-08-01

    By the appointment of the Southern Sweden Power Supply an experimental study has been carried out in order to evaluate the risk for microbial growth in the planned FILTRA steam absorbtion tower at the nuclear power plant in Barsebaeck. Four modelsystems were supplied with nitrogen atmosphere and a relative humidity of 100, 75, 50 and 25 percent. The fifth system received air and 75 percent relative humidity. Samples were collected and analysed for microbial growth after 1, 2, 4 and 8 months. The amounts of microorganisms and the ATP content was monitored. No measureable growth of any significance could be observed after 8 months in any system. An elementary analyses showed that the level of nitrogen and carbon in the stones was below the limit of detection (<0.3 percent C, <0.2 percent N). (author)

  5. Effects of Spatial Localization on Microbial Consortia Growth.

    Directory of Open Access Journals (Sweden)

    Michael Venters

    Full Text Available Microbial consortia are commonly observed in natural and synthetic systems, and these consortia frequently result in higher biomass production relative to monocultures. The focus here is on the impact of initial spatial localization and substrate diffusivity on the growth of a model microbial consortium consisting of a producer strain that consumes glucose and produces acetate and a scavenger strain that consumes the acetate. The mathematical model is based on an individual cell model where growth is described by Monod kinetics, and substrate transport is described by a continuum-based, non-equilibrium reaction-diffusion model where convective transport is negligible (e.g., in a biofilm. The first set of results focus on a single producer cell at the center of the domain and surrounded by an initial population of scavenger cells. The impact of the initial population density and substrate diffusivity is examined. A transition is observed from the highest initial density resulting in the greatest cell growth to cell growth being independent of initial density. A high initial density minimizes diffusive transport time and is typically expected to result in the highest growth, but this expected behavior is not predicted in environments with lower diffusivity or larger length scales. When the producer cells are placed on the bottom of the domain with the scavenger cells above in a layered biofilm arrangement, a similar critical transition is observed. For the highest diffusivity values examined, a thin, dense initial scavenger layer is optimal for cell growth. However, for smaller diffusivity values, a thicker, less dense initial scavenger layer provides maximal growth. The overall conclusion is that high density clustering of members of a food chain is optimal under most common transport conditions, but under some slow transport conditions, high density clustering may not be optimal for microbial growth.

  6. Growth of microbial mixed cultures under anaerobic, alkaline conditions

    International Nuclear Information System (INIS)

    Wenk, M.

    1993-09-01

    Cement and concrete are the most important engineered barrier materials in a repository for low- and intermediate-level waste and thus represent the most significant component of the total disposal inventory. Based on the chemical composition of the concrete used in the repository and the groundwater fluxes in the modelled host rock, it is to be expected that the pH in the near vicinity of the repository could exceed a value of 10.5 for more than a million years. The groundwater in the repository environment also has a limited carbon concentration. Since microorganisms will be present in a repository and can even find suitable living conditions within the waste itself, investigations were carried out in order to establish the extent to which microbial activity is possible under the extreme conditions of the repository near-field. For the investigations, alkalophilic cultures were enriched from samples from alkaline habitats and from Valanginian Marl. Anaerobic bacteria with fermentative, sulfate-reducing and methanogenic metabolism were selected. The growth and activity of the mixed cultures were studied under alkaline conditions and the dependence on pH and carbon concentration determined. All the mixed cultures investigated are alkalophilic. The optimum growth range for the cultures is between pH 9.0 and pH 10.0. The activity limit for the fermentative mixed culture is at pH 12, for the sulfate-reducers at pH 11 and for the methanogens at pH 10.5. Given the limited supply of carbon, the mixed cultures can only grow under slightly alkaline conditions. Only the fermentative cultures are capable of surviving with limited carbon supply at pH 13. (author) 24 figs., 18 tabs., 101 refs

  7. Microbial determination of Cumin by gamma irradiation

    International Nuclear Information System (INIS)

    Motamedi, F.; Abhari, M.; Fathollahi, H.; Arbabi, K.

    2002-01-01

    Cumin is one of the valuable export items of Iran, and like most of the agricultural products it is contaminated by microorganisms. Due to importance of this product, the gamma irradiation method, which has applications in microbial decontamination, has been used for the improving its quality and increasing the shelf life-time. For this purpose pak ages of 10 gr of cumin were irradiated by 2,4,6 and 8 KGy from 60 Co source. With each dose, four samples were irradiated and results were compared with controlled not irradiated samples. According to the standard limitation of bacteria and molds the total optimum doses are 7.5 and 5 KGy respectively

  8. Phosphate solubilization as a microbial strategy for promoting plant growth

    Directory of Open Access Journals (Sweden)

    Mayra Eleonora Beltrán Pineda

    2014-01-01

    Full Text Available Because of the constant application of chemical inputs in Agroecosystem, the cost of crop production and environmental quality of soil and water have been affected. Microorganisms carry out most biogeochemical cycles; therefore, their role is essential for agro ecosystem balance. One such functional group is the phosphate solubilizing microorganisms, which are recognized plant growth promoters. These microbial populations perform an important activity, since in many soils there are large reserves of insoluble phosphorus, as a result of fixing much of the phosphorus fertilizer applied, which cannot be assimilated by the plant. The phosphate solubilizing microorganisms use different solubilization mechanisms such as the production of organic acids, which solubilize theses insoluble phosphates in the rhizosphere region. Soluble phosphates are absorbed by the plant, which enhances their growth and productivity. By using these phosphate reserves in soils, application of chemical fertilizers is decreased, on the one hand, can again be fixed by ions Ca, Al or Fe making them insoluble and, by the other hand, increase the costs of crop production. Microbial populations have been widely studied in different types of ecosystems, both natural and Agroecosystem. Thanks to its effectiveness, in laboratory and field studies, the phosphate solubilizing phenotype is of great interest to microbial ecologists who have begun to establish the molecular basis of the traitr.

  9. Micro-Food Web Structure Shapes Rhizosphere Microbial Communities and Growth in Oak

    Directory of Open Access Journals (Sweden)

    Hazel R. Maboreke

    2018-03-01

    Full Text Available The multitrophic interactions in the rhizosphere impose significant impacts on microbial community structure and function, affecting nutrient mineralisation and consequently plant performance. However, particularly for long-lived plants such as forest trees, the mechanisms by which trophic structure of the micro-food web governs rhizosphere microorganisms are still poorly understood. This study addresses the role of nematodes, as a major component of the soil micro-food web, in influencing the microbial abundance and community structure as well as tree growth. In a greenhouse experiment with Pedunculate Oak seedlings were grown in soil, where the nematode trophic structure was manipulated by altering the proportion of functional groups (i.e., bacterial, fungal, and plant feeders in a full factorial design. The influence on the rhizosphere microbial community, the ectomycorrhizal symbiont Piloderma croceum, and oak growth, was assessed. Soil phospholipid fatty acids were employed to determine changes in the microbial communities. Increased density of singular nematode functional groups showed minor impact by increasing the biomass of single microbial groups (e.g., plant feeders that of Gram-negative bacteria, except fungal feeders, which resulted in a decline of all microorganisms in the soil. In contrast, inoculation of two or three nematode groups promoted microbial biomass and altered the community structure in favour of bacteria, thereby counteracting negative impact of single groups. These findings highlight that the collective action of trophic groups in the soil micro-food web can result in microbial community changes promoting the fitness of the tree, thereby alleviating the negative effects of individual functional groups.

  10. Spatial & Temporal Geophysical Monitoring of Microbial Growth and Biofilm Formation

    Science.gov (United States)

    Davis, C. A.; Pyrak-Nolte, L. J.; Atekwana, E. A.; Werkema, D. D.; Haugen, M. E.

    2009-12-01

    Previous studies have examined the effect of biogenic gases and biomineralization on the acoustic properties of porous media. In this study, we investigated the spatiotemporal effect of microbial growth and biofilm formation on compressional waves and complex conductivity in sand columns. A control column (non-biostimulated) and a biostimulated column were studied in a 2D acoustic scanning apparatus, and a second set of columns were constructed with Ag-AgCl electrodes for complex conductivity measurements. At the completion of the 29-day experiment, compressional wave amplitudes and arrival times for the control column were observed to be relatively uniform over the scanned 2D region. However, the biostimulated sample exhibited a high degree of spatial variability within the column for both the amplitude and arrival times. Furthermore, portions of the sample exhibited increased attenuation (~ 80%) concurrent with an increase in the arrival times, while other portions exhibited decreased attenuation (~ 45%) and decreased arrival time. The acoustic amplitude and arrival times changed significantly in the biostimulated column between Days 5 and 7 of the experiment and are consistent with a peak in the imaginary conductivity (σ”) values. The σ” response corresponds to different stages of biofilm development. That is, we interpret the peak σ” with the maximum biofilm thickness and decreasing σ” due to cell death or detachment. Environmental scanning electron microscope (ESEM) imaging confirmed microbial cell attachment to sand surfaces in the biostimulated columns, showed apparent differences in the morphology of attached biomass between regions of increased and decreased attenuation, and indicated no mineral precipitation or biomineralization. The heterogeneity in the elastic properties arises from the differences in the morphology and structure of attached biofilms. These results suggest that combining acoustic imaging and complex conductivity techniques

  11. Microbial manipulation of host sex determination

    NARCIS (Netherlands)

    Beukeboom, Leo W.

    A recent study in the lepidopteran Ostrinia scapulalis shows that endosymbionts can actively manipulate the sex determination mechanism of their host. Wolbachia bacteria alter the sex-specific splicing of the doublesex master switch gene. In ZZ males of this female heterogametic system, the female

  12. Life-history trait of the Mediterranean keystone species Patella rustica: growth and microbial bioerosion

    Directory of Open Access Journals (Sweden)

    I. PRUSINA

    2015-05-01

    Full Text Available The age and shell growth patterns in populations of Patella rustica of the Adriatic Sea were determined by analyzing the inner growth lines visible in shell sections. Marginal increment analysis showed annual periodicity with annual growth line being deposited in May. The growth analysis of 120 individual shells showed that 90.8 % of collected individuals were less than 4 years of age and only two individuals (1.6 % were older than 6 years. Population structure was described and the generalized von Bertalanffy growth parameters were calculated: asymptotic length (L∞ was 38.22 mm and the growth constant (K was 0.30 year-1. Growth performance index value of P. rustica (Ø’ was 2.64 and is among the lowest ranges reported for limpet species. Patella rustica shells were degraded to different degrees by microbial bioerosion. Microboring organisms identified were pseudofilamentous and filamentous cyanobacteria Hormathonema paulocellulare, Hyella caespitosa, Mastigocoleus testarum and Leptolyngbya sp. The overall intensity of infestation was relatively low, but increased in severity with shell length. The damage was most often restricted to the oldest parts of the shell, i.e. apex of the shell, posing difficulties in determining the exact position of the first growth line. The present study is first to introduce the use of inner growth lines in Patella rustica shell sections as a reliable method for age determination and it provides the first insight into the growth patterns of this keystone species while taking the interference of microbial shell bioerosion in consideration.

  13. Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides

    Science.gov (United States)

    Vega Thurber, Rebecca; Burkepile, Deron E.; Correa, Adrienne M. S.; Thurber, Andrew R.; Shantz, Andrew A.; Welsh, Rory; Pritchard, Catharine; Rosales, Stephanie

    2012-01-01

    With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs. PMID:22957055

  14. Macroalgae decrease growth and alter microbial community structure of the reef-building coral, Porites astreoides.

    Directory of Open Access Journals (Sweden)

    Rebecca Vega Thurber

    Full Text Available With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1 increases or 2 decreases in microbial taxa already present in corals, 3 establishment of new taxa to the coral microbiome, and 4 vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs.

  15. Determinants of economic growth in BRIC countries

    OpenAIRE

    Rajjev K. Goel

    2011-01-01

    We study economic growth in four emerging economies - Brazil, Russia, India, and China (BRIC). Questions addressed are: (a) How do medium term growth determinants differ from short term determinants? (b) What are differences between growth effects of aggregate versus disaggregated exports? And (c) Does lower institutional quality hinder growth? Results show that while BRIC nations have higher growth, there are significant within-group differences. China and Russia mostly showed higher growth,...

  16. Monitoring microbial growth and activity using spectral induced polarization and low-field nuclear magnetic resonance

    Science.gov (United States)

    Zhang, Chi; Keating, Kristina; Revil, Andre

    2015-04-01

    Microbes and microbial activities in the Earth's subsurface play a significant role in shaping subsurface environments and are involved in environmental applications such as remediation of contaminants in groundwater and oil fields biodegradation. Stimulated microbial growth in such applications could cause wide variety of changes of physical/chemical properties in the subsurface. It is critical to monitor and determine the fate and transportation of microorganisms in the subsurface during such applications. Recent geophysical studies demonstrate the potential of two innovative techniques, spectral induced polarization (SIP) and low-field nuclear magnetic resonance (NMR), for monitoring microbial growth and activities in porous media. The SIP measures complex dielectric properties of porous media at low frequencies of exciting electric field, and NMR studies the porous structure of geologic media and characterizes fluids subsurface. In this laboratory study, we examined both SIP and NMR responses from bacterial growth suspension as well as suspension mixed with silica sands. We focus on the direct contribution of microbes to the SIP and NMR signals in the absence of biofilm formation or biomineralization. We used Zymomonas mobilis and Shewanella oneidensis (MR-1) for SIP and NMR measurements, respectively. The SIP measurements were collected over the frequency range of 0.1 - 1 kHz on Z. mobilis growth suspension and suspension saturated sands at different cell densities. SIP data show two distinct peaks in imaginary conductivity spectra, and both imaginary and real conductivities increased as microbial density increased. NMR data were collected using both CPMG pulse sequence and D-T2 mapping to determine the T2-distribution and diffusion properties on S. oneidensis suspension, pellets (live and dead), and suspension mixed with silica sands. NMR data show a decrease in the T2-distribution in S. oneidensis suspension saturated sands as microbial density increase. A

  17. Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

    Science.gov (United States)

    Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

    2010-05-01

    Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivumyeast extract then for those growing on glucose, i.e. the effect of elevated CO2 was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). After adding glucose, enzyme activities under elevated CO2 were 1.2-1.9-fold higher than under ambient CO2. This indicates the increased activity of microorganisms, which leads to accelerated C turnover in soil under elevated CO2. Our results clearly showed that the functional characteristics of the soil microbial community (i.e. specific growth rates and enzymes activity) rather than total microbial biomass

  18. Impact of Microbial Growth on Subsurface Perfluoroalkyl Acid Transport

    Science.gov (United States)

    Weathers, T. S.; Higgins, C. P.; Sharp, J.

    2014-12-01

    The fate and transport of poly and perfluoroalkyl substances (PFASs) in the presence of active microbial communities has not been widely investigated. These emerging contaminants are commonly utilized in aqueous film-forming foams (AFFF) and have often been detected in groundwater. This study explores the transport of a suite of perfluorocarboxylic acids and perfluoroalkylsulfonates, including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in microbially active settings. Single point organic carbon normalized sorption coefficients derived by exposing inactive cellular material to PFASs result in more than an order of magnitude increase in sorption compared to soil organic carbon sorption coefficients found in literature. For example, the sorption coefficients for PFOS are 4.05±0.07 L/kg and 2.80±0.08 L/kg for cellular organic carbon and soil organic carbon respectively. This increase in sorption, coupled with enhanced extracellular polymeric substance production observed during growth of a common hydrocarbon degrading soil microbe exposed to source-level concentrations of PFASs (10 mg/L of 11 analytes, 110 mg/L total) may result in PFAS retardation in situ. To address the upscaling of this phenomenon, flow-through columns packed with low-organic carbon sediment and biostimulated with 10 mg/L glucose were exposed to PFAS concentrations from 15 μg/L to 10 mg/L of each 11 analytes. Breakthrough and tailing of each analyte was measured and modeled with Hydrus-1D to explore sorption coefficients over time for microbially active columns.

  19. Augmenting Plant Immune Responses and Biological Control by Microbial Determinants

    Directory of Open Access Journals (Sweden)

    Sang Moo Lee

    2015-09-01

    Full Text Available Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.

  20. Factors limiting microbial growth and activity at a proposed high-level nuclear repository, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Kieft, T.L.; Kovacik, W.P. Jr.; Ringelberg, D.B.; White, D.C.; Haldeman, D.L.; Amy, P.S.; Hersman, L.E.

    1997-01-01

    As part of the characterization of Yucca Mountain, Nev., as a potential repository for high-level nuclear waste, volcanic tuff was analyzed for microbial abundance and activity. Tuff was collected aseptically from nine sites along a tunnel in Yucca Mountain. Microbial abundance was generally low: direct microscopic cell counts were near detection limits at all sites (3.2 X 10(1) to 2.0 X 10(5) cells g-1 [dry weight]); plate counts of aerobic heterotrophs ranged from 1.0 X 10(1) to 3.2 X 10(3) CFU g-1 (dry weight). Phospholipid fatty acid concentrations (0.1 to 3.7 pmol g-1) also indicated low microbial biomasses: diglyceride fatty acid concentrations, indicative of dead cells, were in a similar range (0.2 to 2.3 pmol g-1). Potential microbial activity was quantified as 14CO2 production in microcosms containing radiolabeled substrates (glucose, acetate, and glutamic acid); amendments with water and nutrient solutions (N and P) were used to test factors potentially limiting this activity. Similarly, the potential for microbial growth and the factors limiting growth were determined by performing plate counts before and after incubating volcanic tuff samples for 24 h under various conditions: ambient moisture, water-amended, and amended with various nutrient solutions (N, P, and organic C). A high potential for microbial activity was demonstrated by high rates of substrate mineralization (as much as 70% of added organic C in 3 weeks). Water was the major limiting factor to growth and microbial activity, while amendments with N and P resulted in little further stimulation. Organic C amendments stimulated growth more than water alone

  1. Microbial Community Structure of Casing Soil During Mushroom Growth

    Institute of Scientific and Technical Information of China (English)

    CAI Wei-Ming; YAO Huai-Ying; FENG Wei-Lin; JIN Qun-Li; LIU Yue-Yan; LI Nan-Yi; ZHENG Zhong

    2009-01-01

    The culturable bacterial population and phospholipid fatty acid (PLFA)profile of casing soil were investigated at different mushroom (Agaricus bisporusI cropping stages.The change in soil bacterial PLFAs was always accompanied by a change in the soil culturable bacterial population in the first flush.Comparatively higher culturable bacterial population and bacterial PLFAs were found in the casing soil at the primordia formation stage of the first flush.There was a significant increase in the ratio of fungal to bacterial PLFAs during mushroom growth.Multivariate analysis of PLFA data demonstrated that the mushroom cropping stage could considerably affect the microbial community structure of the casing soil.The bacterial population increased significantly from casing soil application to the primordia formation stage of the first flush.Casing soil application resulted in an increase in the ratio of gram-negative bacterial PLFAs to gram-positive bacterial PLFAs,suggesting that some gram-negative bacteria might play an important role in mushroom sporophore initiation.

  2. Microbial Growth and Carbon Use Efficiency in the Rhizosphere and Root-Free Soil

    Science.gov (United States)

    Blagodatskaya, Evgenia; Blagodatsky, Sergey; Anderson, Traute-Heidi; Kuzyakov, Yakov

    2014-01-01

    Plant-microbial interactions alter C and N balance in the rhizosphere and affect the microbial carbon use efficiency (CUE)–the fundamental characteristic of microbial metabolism. Estimation of CUE in microbial hotspots with high dynamics of activity and changes of microbial physiological state from dormancy to activity is a challenge in soil microbiology. We analyzed respiratory activity, microbial DNA content and CUE by manipulation the C and nutrients availability in the soil under Beta vulgaris. All measurements were done in root-free and rhizosphere soil under steady-state conditions and during microbial growth induced by addition of glucose. Microorganisms in the rhizosphere and root-free soil differed in their CUE dynamics due to varying time delays between respiration burst and DNA increase. Constant CUE in an exponentially-growing microbial community in rhizosphere demonstrated the balanced growth. In contrast, the CUE in the root-free soil increased more than three times at the end of exponential growth and was 1.5 times higher than in the rhizosphere. Plants alter the dynamics of microbial CUE by balancing the catabolic and anabolic processes, which were decoupled in the root-free soil. The effects of N and C availability on CUE in rhizosphere and root-free soil are discussed. PMID:24722409

  3. Determinants of economic growth: will data tell?

    OpenAIRE

    Ciccone, Antonio; Jarociński, Marek

    2008-01-01

    Many factors inhibiting and facilitating economic growth have been suggested. Will international income data tell which matter when all are treated symmetrically a priori? We find that growth determinants emerging from agnostic Bayesian model averaging and classical model selection procedures are sensitive to income differences across datasets. For example, many of the 1975-1996 growth determinants according to World Bank income data turn out to be irrelevant when using Penn World Table data ...

  4. Critical control points for the management of microbial growth in HVAC systems

    NARCIS (Netherlands)

    Gommers, S; Franchimon, F.; Bronswijk, van J.E.M.H.; Strøm-Tejsen, P; Olesen, BW; Wargocki, P; Zukowska, D; Toftum, J

    2008-01-01

    Office buildings with HVAC systems consistently report Sick Building Symptoms that are derived from microbial growth. We used the HACCP methodology to find the main critical control points (CCPs) for microbial management of HVAC systems in temperate climates. Desk research revealed relative humidity

  5. The effect of substrate modification on microbial growth on surfaces

    International Nuclear Information System (INIS)

    Brown, Angela Ann

    1998-01-01

    The principle aim of the program was to produce a novel, non-leaching antimicrobial surface for commercial development and future use in the liquid food packaging industry. Antimicrobial surfaces which exist presently have been produced to combat the growth of prokaryotic organisms and usually function as slow release systems. A system which could inhibit eukaryotic growth without contaminating the surrounding 'environment' with the inhibitor was considered of great commercial importance. The remit of this study was concerned with creating a surface which could control the growth of eukaryotic organisms found in fruit juice with particular interest in the yeast, Saccharomyces cerevisiae. Putative antimicrobial surfaces were created by the chemical modification of the test substrate polymers; nylon and ethylvinyl alcohol (EVOH). Surfaces were chemically modified by the covalent coupling of antimicrobial agents known to be active against the yeast Saccharomyces cerevisiae as ascertained by the screening process determining the minimum inhibitory concentration (MIC) values of agents in the desired test medium. During the study it was found that a number of surfaces did appear to inhibit yeast growth in fruit juice, however on further investigation the apparent inhibitory effect was discovered to be the result of un-bound material free in the test medium. On removing the possibility of any un-bound material present on the test surface, by a series of surface washings, the inhibitory effect on yeast growth was eliminated. Of the agents tested only one appeared to have an inhibitory effect which could be attributed to a true antimicrobial surface effect, Amical 48. As there is little known about this agent in the literature, its affect on yeast growth was examined and in particular a proposal for the mode of action on yeast is discussed, providing a plausible explanation for the inhibitory effect observed when this agent is covalently immobilised onto nylon. (author)

  6. Plant, microbial and ecosystem carbon use efficiencies interact to stabilize microbial growth as a fraction of gross primary production.

    Science.gov (United States)

    Sinsabaugh, Robert L; Moorhead, Daryl L; Xu, Xiaofeng; Litvak, Marcy E

    2017-06-01

    The carbon use efficiency of plants (CUE a ) and microorganisms (CUE h ) determines rates of biomass turnover and soil carbon sequestration. We evaluated the hypothesis that CUE a and CUE h counterbalance at a large scale, stabilizing microbial growth (μ) as a fraction of gross primary production (GPP). Collating data from published studies, we correlated annual CUE a , estimated from satellite imagery, with locally determined soil CUE h for 100 globally distributed sites. Ecosystem CUE e , the ratio of net ecosystem production (NEP) to GPP, was estimated for each site using published models. At the ecosystem scale, CUE a and CUE h were inversely related. At the global scale, the apparent temperature sensitivity of CUE h with respect to mean annual temperature (MAT) was similar for organic and mineral soils (0.029°C -1 ). CUE a and CUE e were inversely related to MAT, with apparent sensitivities of -0.009 and -0.032°C -1 , respectively. These trends constrain the ratio μ : GPP (= (CUE a  × CUE h )/(1 - CUE e )) with respect to MAT by counterbalancing the apparent temperature sensitivities of the component processes. At the ecosystem scale, the counterbalance is effected by modulating soil organic matter stocks. The results suggest that a μ : GPP value of c. 0.13 is a homeostatic steady state for ecosystem carbon fluxes at a large scale. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  7. Biochar and microbial signaling: production conditions determine effects on microbial communication

    Science.gov (United States)

    Masiello, Caroline A.; Chen, Ye; Gao, Xiaodong; Liu, Shirley; Cheng, Hsiao-Ying; Bennett, Matthew R.; Rudgers, Jennifer A.; Wagner, Daniel S.; Zygourakis, Kyriacos; Silberg, Jonathan J.

    2013-01-01

    Charcoal has a long soil residence time, which has resulted in its production and use as a carbon sequestration technique (biochar). A range of biological effects can be triggered by soil biochar that can positively and negatively influence carbon storage, such as changing the decomposition rate of organic matter and altering plant biomass production. Sorption of cellular signals has been hypothesized to underlie some of these effects, but it remains unknown whether the binding of biochemical signals occurs, and if so, on time scales relevant to microbial growth and communication. We examined biochar sorption of N-3-oxo-dodecanoyl-L-homoserine lactone, an acyl-homoserine lactone (AHL) intercellular signaling molecule used by many gram-negative soil microbes to regulate gene expression. We show that wood biochars disrupt communication within a growing multicellular system that is made up of sender cells that synthesize AHL and receiver cells that express green fluorescent protein in response to an AHL signal. However, biochar inhibition of AHL-mediated cell-cell communication varied, with the biochar prepared at 700°C (surface area of 301 m2/g) inhibiting cellular communication 10-fold more than an equivalent mass of biochar prepared at 300°C (surface area of 3 m2/g). These findings provide the first direct evidence that biochars elicit a range of effects on gene expression dependent on intercellular signaling, implicating the method of biochar preparation as a parameter that could be tuned to regulate microbial-dependent soil processes, like nitrogen fixation and pest attack of root crops. PMID:24066613

  8. Biochar and microbial signaling: production conditions determine effects on microbial communication.

    Science.gov (United States)

    Masiello, Caroline A; Chen, Ye; Gao, Xiaodong; Liu, Shirley; Cheng, Hsiao-Ying; Bennett, Matthew R; Rudgers, Jennifer A; Wagner, Daniel S; Zygourakis, Kyriacos; Silberg, Jonathan J

    2013-10-15

    Charcoal has a long soil residence time, which has resulted in its production and use as a carbon sequestration technique (biochar). A range of biological effects can be triggered by soil biochar that can positively and negatively influence carbon storage, such as changing the decomposition rate of organic matter and altering plant biomass production. Sorption of cellular signals has been hypothesized to underlie some of these effects, but it remains unknown whether the binding of biochemical signals occurs, and if so, on time scales relevant to microbial growth and communication. We examined biochar sorption of N-3-oxo-dodecanoyl-L-homoserine lactone, an acyl-homoserine lactone (AHL) intercellular signaling molecule used by many gram-negative soil microbes to regulate gene expression. We show that wood biochars disrupt communication within a growing multicellular system that is made up of sender cells that synthesize AHL and receiver cells that express green fluorescent protein in response to an AHL signal. However, biochar inhibition of AHL-mediated cell-cell communication varied, with the biochar prepared at 700 °C (surface area of 301 m(2)/g) inhibiting cellular communication 10-fold more than an equivalent mass of biochar prepared at 300 °C (surface area of 3 m(2)/g). These findings provide the first direct evidence that biochars elicit a range of effects on gene expression dependent on intercellular signaling, implicating the method of biochar preparation as a parameter that could be tuned to regulate microbial-dependent soil processes, like nitrogen fixation and pest attack of root crops.

  9. Microbial growth associated with granular activated carbon in a pilot water treatment facility.

    Science.gov (United States)

    Wilcox, D P; Chang, E; Dickson, K L; Johansson, K R

    1983-01-01

    The microbial dynamics associated with granular activated carbon (GAC) in a pilot water treatment plant were investigated over a period of 16 months. Microbial populations were monitored in the influent and effluent waters and on the GAC particles by means of total plate counts and ATP assays. Microbial populations between the influent and effluent waters of the GAC columns generally increased, indicating microbial growth. The dominant genera of microorganisms isolated from interstitial waters and GAC particles were Achromobacter, Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Corynebacterium, Micrococcus, Microcyclus, Paracoccus, and Pseudomonas. Coliform bacteria were found in small numbers in the effluents from some of the GAC columns in the later months of the study. Oxidation of influent waters with ozone and maintenance of aerobic conditions on the GAC columns failed to appreciably enhance the microbial growth on GAC. PMID:6625567

  10. Earthworms (Amynthas spp. increase common bean growth, microbial biomass, and soil respiration

    Directory of Open Access Journals (Sweden)

    Julierme Zimmer Barbosa

    2017-10-01

    Full Text Available Few studies have evaluated the effect of earthworms on plants and biological soil attributes, especially among legumes. The objective of this study was to evaluate the influence of earthworms (Amynthas spp. on growth in the common bean (Phaseolus vulgaris L. and on soil biological attributes. The experiment was conducted in a greenhouse using a completely randomized design with five treatments and eight repetitions. The treatments consisted of inoculation with five different quantities of earthworms of the genus Amynthas (0, 2, 4, 6, and 8 worms per pot. Each experimental unit consisted of a plastic pot containing 4 kg of soil and two common bean plants. The experiment was harvested 38 days after seedling emergence. Dry matter and plant height, soil respiration, microbial respiration, microbial biomass, and metabolic quotient were determined. Earthworm recovery in our study was high in number and mass, with all values above 91.6% and 89.1%, respectively. In addition, earthworm fresh biomass decreased only in the treatment that included eight earthworms per pot. The presence of earthworms increased the plant growth and improved soil biological properties, suggesting that agricultural practices that favor the presence of these organisms can be used to increase the production of common bean, and the increased soil CO2 emission caused by the earthworms can be partially offset by the addition of common bean crop residues to the soil.

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

    Science.gov (United States)

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

    2017-11-01

    offered similar results for diets comparison, but both methods presented contrasting results for microbial growth in SOL and LIQ phases. The study showed that fermentation parameters remained fairly stable over the commonly used sampling period (days 8 to 14), but shifts in microbial populations were detected. Moreover, microbial populations differed markedly from those in the inocula, which indicates the difficulty of directly transposing results on microbial populations developed in Rusitec fermenters to in vivo conditions.

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

    Science.gov (United States)

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

    2010-08-01

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

  13. Effect of dietary olive leaves and rosemary on microbial growth and ...

    African Journals Online (AJOL)

    Effect of dietary olive leaves and rosemary on microbial growth and lipid oxidation of turkey breast during refrigerated storage. ... During this period olive leaves were more effective in inhibiting bacterial growth than rosemary. Keywords: Antioxidant additives, α-tocopherol, turkey meat, herbs, spices, meat quality ...

  14. Linking genes to microbial growth kinetics: an integrated biochemical systems engineering approach

    NARCIS (Netherlands)

    Koutinas, M.; Kiparissides, A.; Silva-Rocha, R.; Lam, M.C.; Martins Dos Santos, V.A.P.; Lorenzo, de V.; Pistikopoulos, E.N.; Mantalaris, A.

    2011-01-01

    The majority of models describing the kinetic properties of a microorganism for a given substrate are unstructured and empirical. They are formulated in this manner so that the complex mechanism of cell growth is simplified. Herein, a novel approach for modelling microbial growth kinetics is

  15. Microbial biofilm growth on irradiated, spent nuclear fuel cladding

    International Nuclear Information System (INIS)

    Bruhn, D.F.; Frank, S.M.; Roberto, F.F.; Pinhero, P.J.; Johnson, S.G.

    2009-01-01

    A fundamental criticism regarding the potential for microbial influenced corrosion in spent nuclear fuel cladding or storage containers concerns whether the required microorganisms can, in fact, survive radiation fields inherent in these materials. This study was performed to unequivocally answer this critique by addressing the potential for biofilm formation, the precursor to microbial-influenced corrosion, in radiation fields representative of spent nuclear fuel storage environments. This study involved the formation of a microbial biofilm on irradiated spent nuclear fuel cladding within a hot cell environment. This was accomplished by introducing 22 species of bacteria, in nutrient-rich media, to test vessels containing irradiated cladding sections and that was then surrounded by radioactive source material. The overall dose rate exceeded 2 Gy/h gamma/beta radiation with the total dose received by some of the bacteria reaching 5 x 10 3 Gy. This study provides evidence for the formation of biofilms on spent-fuel materials, and the implication of microbial influenced corrosion in the storage and permanent deposition of spent nuclear fuel in repository environments

  16. The contribution of microbial biotechnology to economic growth and employment creation.

    Science.gov (United States)

    Timmis, Kenneth; de Lorenzo, Victor; Verstraete, Willy; Ramos, Juan Luis; Danchin, Antoine; Brüssow, Harald; Singh, Brajesh K; Timmis, James Kenneth

    2017-09-01

    Our communication discusses the profound impact of bio-based economies - in particular microbial biotechnologies - on SDG 8: Promote sustained, inclusive and sustainable economic growth, full and productive employment and decent work for all. A bio-based economy provides significant potential for improving labour supply, education and investment, and thereby for substantially increasing the demographic dividend. This, in turn, improves the sustainable development of economies. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  17. Growth and element flux at fine taxonomic resolution in natural microbial communities

    Science.gov (United States)

    Hungate, Bruce; Mau, Rebecca; Schwartz, Egbert; Caporaso, J. Gregory; Dijkstra, Paul; van Gestel, Natasja; Koch, Benjamin J.; Liu, Cindy M.; McHugh, Theresa; Marks, Jane C.; Morrissey, Ember; Price, Lance B.

    2015-04-01

    Microorganisms are the engines of global biogeochemical cycles, driving half of all photosynthesis and nearly all decomposition. Yet, quantifying the rates at which uncultured microbial taxa grow and transform elements in intact and highly diverse natural communities in the environment remains among the most pressing challenges in microbial ecology today. Here, we show how shifts in the density of DNA caused by stable isotope incorporation can be used to estimate the growth rates of individual bacterial taxa in intact soil communities. We found that the distribution of growth rates followed the familiar lognormal distribution observed for the abundances, biomasses, and traits of many organisms. Growth rates of most bacterial taxa increased in response to glucose amendment, though the increase in growth observed for many taxa was larger than could be explained by direct utilization of the added glucose for growth, illustrating that glucose addition indirectly stimulated the utilization of other substrates. Variation in growth rates and phylogenetic distances were quantitatively related, connecting evolutionary history and biogeochemical function in intact soil microbial communities. Our approach has the potential to identify biogeochemically significant taxa in the microbial community and quantify their contributions to element transformations and ecosystem processes.

  18. DETERMINATION OF THE SPECIFIC GROWTH RATE ON ...

    African Journals Online (AJOL)

    Sewage generation is one of the dense problems Nigerians encounter on daily bases, mostly at the urbanized area where factories and industries are located. This paper is aimed at determining the specific growth rate “K” of biological activities on cassava wastewater during degradation using Michaelis-Menten Equation.

  19. Comparison of Two Mechanistic Microbial Growth Models to Estimate Shelf Life of Perishable Food Package under Dynamic Temperature Conditions

    Directory of Open Access Journals (Sweden)

    Dong Sun Lee

    2014-01-01

    Full Text Available Two mechanistic microbial growth models (Huang’s model and model of Baranyi and Roberts given in differential and integrated equation forms were compared in predicting the microbial growth and shelf life under dynamic temperature storage and distribution conditions. Literatures consistently reporting the microbial growth data under constant and changing temperature conditions were selected to obtain the primary model parameters, set up the secondary models, and apply them to predict the microbial growth and shelf life under fluctuating temperatures. When evaluated by general estimation behavior, bias factor, accuracy factor, and root-mean-square error, Huang’s model was comparable to Baranyi and Roberts’ model in the capability to estimate microbial growth under dynamic temperature conditions. Its simple form of single differential equation incorporating directly the growth rate and lag time may work as an advantage to be used in online shelf life estimation by using the electronic device.

  20. Soil C and N availability determine the priming effect: microbial N mining and stoichiometric decomposition theories

    Science.gov (United States)

    Chen, Ruirui; Senbayram, Mehmet; Blagodatsky, Sergey; Dittert, Klaus; Lin, Xiangui; Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2014-05-01

    The increasing input of anthropogenically derived nitrogen (N) to ecosystems raises a crucial question: how does available N modify the decomposer community and thus affects the mineralization of soil organic matter (SOM). Moreover, N input modifies the priming effect (PE), that is, the effect of fresh organics on the microbial decomposition of SOM. We studied the interactive effects of C and N on SOM mineralization (by natural 13C labelling adding C4-sucrose or C4-maize straw to C3-soil) in relation to microbial growth kinetics and to the activities of five hydrolytic enzymes. This encompasses the groups of parameters governing two mechanisms of priming effects - microbial N mining and stoichiometric decomposition theories. In sole C treatments, positive PE was accompanied by a decrease in specific microbial growth rates, confirming a greater contribution of K-strategists to the decomposition of native SOM. Sucrose addition with N significantly accelerated mineralization of native SOM, whereas mineral N added with plant residues accelerated decomposition of plant residues. This supports the microbial mining theory in terms of N limitation. Sucrose addition with N was accompanied by accelerated microbial growth, increased activities of β-glucosidase and cellobiohydrolase, and decreased activities of xylanase and leucine amino peptidase. This indicated an increased contribution of r-strategists to the PE and to decomposition of cellulose but the decreased hemicellulolytic and proteolytic activities. Thus, the acceleration of the C cycle was primed by exogenous organic C and was controlled by N. This confirms the stoichiometric decomposition theory. Both K- and r-strategists were beneficial for priming effects, with an increasing contribution of K-selected species under N limitation. Thus, the priming phenomenon described in 'microbial N mining' theory can be ascribed to K-strategists. In contrast, 'stoichiometric decomposition' theory, that is, accelerated OM

  1. Determination of Bacterial Growth in Culture Media

    International Nuclear Information System (INIS)

    Elly Ellyna Rashid; Shariza Hanim Zainal Abidin; Mok, P.S.

    2015-01-01

    Bacteria is one of the important microorganism in our daily life. Bacteria provides human beings with products in the field of medical, industry, food, agriculture and others. Determination of bacteria growth is important so that we can enjoy the most benefit from it. Spread-plate method is one of the methods to obtain the bacterial counts. Agar plates, such as Nutrient Agar or Plate Count Agar are usually used for this purpose. Bacterial culture will be diluted first before being spread on the agar plate and incubated at specific temperature. The number of bacteria in colony-forming unit (CFU) will be counted the next day. The count will be used to determine the bacterial growth. (author)

  2. Effect of temperature on microbial growth rate - thermodynamic analysis, the arrhenius and eyring-polanyi connection

    Science.gov (United States)

    The objective of this work is to develop a new thermodynamic mathematical model for evaluating the effect of temperature on the rate of microbial growth. The new mathematical model is derived by combining the Arrhenius equation and the Eyring-Polanyi transition theory. The new model, suitable for ...

  3. The relative importance of exogenous and substrate-derived nitrogen for microbial growth during leaf decomposition

    Science.gov (United States)

    B.M. Cheever; J. R. Webster; E. E. Bilger; S. A. Thomas

    2013-01-01

    Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with

  4. Accelerated microbial turnover but constant growth efficiency with warming in soil

    Science.gov (United States)

    Shannon B. Hagerty; Kees Jan van Groenigen; Steven D. Allison; Bruce A. Hungate; Egbert Schwartz; George W. Koch; Randall K. Kolka; Paul. Dijkstra

    2014-01-01

    Rising temperatures are expected to reduce global soil carbon (C) stocks, driving a positive feedback to climate change1-3. However, the mechanisms underlying this prediction are not well understood, including how temperature affects microbial enzyme kinetics, growth effiency (MGE), and turnover4,5. Here, in a laboratory...

  5. Microbial growth in Acrocomia aculeata pulp oil, Jatropha curcas oil, and their respective biodiesels under simulated storage conditions

    Directory of Open Access Journals (Sweden)

    Juciana Clarice Cazarolli

    2016-12-01

    Full Text Available With increasing demands for biodiesel in Brazil, diverse oil feedstocks have been investigated for their potentials for biodiesel production. Due to the high biodegradability of natural oils and their respective biodiesels, microbial growths and consequent deterioration of final product quality are generally observed during storage. This study was aimed at evaluating the susceptibility of Acrocomia aculeata pulp oil and Jatropha curcas oil as well as their respective biodiesels to biodeterioration during a simulated storage period. The experiment was conducted in microcosms containing oil/biodiesel and an aqueous phase over 30 d. The levels of microbial contamination included biodiesel and oil as received, inoculated with fungi, and sterile. Samples were collected every 7 d to measure pH, surface tension, acidity index, and microbial biomass. The initial and final ester contents of the biodiesels were also determined by gas chromatography. The major microbial biomass was detected in A. aculeata pulp and J. curcas biodiesels. Significant reductions in pH values were observed for treatments with A. aculeata pulp biodiesel as a carbon source (p

  6. Influence of heterotrophic microbial growth on biological oxidation of pyrite

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, E.A.; Silverstein, J. [University of Nevada, Reno, NV (United States). Dept. of Civil Engineering

    2002-12-15

    Experiments were carried out to examine the possibility that enhanced growth of heterotrophic (non-iron-oxidising) bacteria would inhibit pyrite oxidation by Acidithiobacillus ferroxidans by out-competing the more slowly growing autotrophs for oxygen, nutrients or even attachment sites on the mineral surface. Glucose was added to microcosms containing pyrite, acidic mineral solution and cultures of A-ferrooxidans and Acidiphilium acidophilus under various experimental conditions. Results suggest that encouraging the growth of heterotrophic microorganisms under acid mine drainage conditions may be a feasible strategy for decreasing both the rate and the extent of sulfide mineral oxidation. 43 refs., 8 figs., 3 tabs.

  7. Determinants of the microbial community structure of eutrophic, hyporheic river sediments polluted with chlorinated aliphatic hydrocarbons

    NARCIS (Netherlands)

    Hamonts, K.; Ryngaert, A.; Smidt, H.; Springael, D.; Dejonghe, W.

    2014-01-01

    Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. As biotransformation of CAHs in the impacted river sediments might be an effective remediation strategy, we investigated the determinants of the microbial community structure of eutrophic,

  8. Prevention of Acid Mine Drainage Through Complexation of Ferric Iron by Soluble Microbial Growth Products

    Science.gov (United States)

    Pandey, S.; Yacob, T. W.; Silverstein, J.; Rajaram, H.; Minchow, K.; Basta, J.

    2011-12-01

    Acid mine drainage (AMD) is a widespread environmental problem with deleterious impacts on water quality in streams and watersheds. AMD is generated largely by the oxidation of metal sulfides (i.e. pyrite) by ferric iron. This abiotic reaction is catalyzed by conversion of ferrous to ferric iron by iron and sulfur oxidizing microorganisms. Biostimulation is currently being investigated as an attempt to inhibit the oxidation of pyrite and growth of iron oxidizing bacteria through addition of organic carbon. This may stimulate growth of indigenous communities of acidophilic heterotrophic bacteria to compete for oxygen. The goal of this research is to investigate a secondary mechanism associated with carbon addition: complexation of free Fe(III) by soluble microbial growth products (SMPs) produced by microorganisms growing in waste rock. Exploratory research at the laboratory scale examined the effect of soluble microbial products (SMPs) on the kinetics of oxidation of pure pyrite during shaker flask experiments. The results confirmed a decrease in the rate of pyrite oxidation that was dependent upon the concentration of SMPs in solution. We are using these data to verify results from a pyrite oxidation model that accounts for SMPs. This reactor model involves differential-algebraic equations incorporating total component mass balances and mass action laws for equilibrium reactions. Species concentrations determined in each time step are applied to abiotic pyrite oxidation rate expressions from the literature to determine the evolution of total component concentrations. The model was embedded in a parameter estimation algorithm to determine the reactive surface area of pyrite in an abiotic control experiment, yielding an optimized value of 0.0037 m2. The optimized model exhibited similar behavior to the experiment for this case; the root mean squared of residuals for Fe(III) was calculated to be 7.58 x 10-4 M, which is several orders of magnitude less than the actual

  9. Green tea yogurt: major phenolic compounds and microbial growth.

    Science.gov (United States)

    Amirdivani, Shabboo; Baba, Ahmad Salihin Hj

    2015-07-01

    The purpose of this study was to evaluate fermentation of milk in the presence of green tea (Camellia sinensis) with respect to changes in antioxidant activity, phenolic compounds and the growth of lactic acid bacteria. Pasteurized full fat cow's milk and starter culture were incubated at 41 °C in the presence of two different types of green tea extracts. The yogurts formed were refrigerated (4 °C) for further analysis. The total phenolic content was highest (p yogurt (MGT) followed by steam-treated green tea (JGT) and plain yogurts. Four major compounds in MGTY and JGTY were detected. The highest concentration of major phenolic compounds in both samples was related to quercetin-rhamnosylgalactoside and quercetin-3-O-galactosyl-rhamnosyl-glucoside for MGTY and JGTY respectively during first 7 day of storage. Diphenyl picrylhydrazyl and ferric reducing antioxidant power methods showed highest antioxidant capacity in MGTY, JGTY and PY. Streptococcus thermophillus and Lactobacillus spp. were highest in MGTY followed by JGTY and PY. This paper evaluates the implementation of green tea yogurt as a new product with functional properties and valuable component to promote the growth of beneficial yogurt bacteria and prevention of oxidative stress by enhancing the antioxidant activity of yogurt.

  10. Effect of different film packaging on microbial growth in minimally processed cactus pear (Opuntia ficus-indica).

    Science.gov (United States)

    Palma, A; Mangia, N P; Fadda, A; Barberis, A; Schirra, M; D'Aquino, S

    2013-01-01

    Microorganisms are natural contaminants of fresh produce and minimally processed products, and contamination arises from a number of sources, including the environment, postharvest handling and processing. Fresh-cut products are particularly susceptible to microbial contaminations because of the changes occurring in the tissues during processing. In package gas composition of modified atmosphere packaging (MAP) in combination with low storage temperatures besides reducing physiological activity of packaged produce, can also delay pathogen growth. Present study investigated on the effect of MAPs, achieved with different plastic films, on microbial growth of minimally processed cactus pear (Opuntio ficus-indica) fruit. Five different plastic materials were used for packaging the manually peeled fruit. That is: a) polypropylene film (Termoplast MY 40 micron thickness, O2 transmission rate 300 cc/m2/24h); b) polyethylene film (Bolphane BHE, 11 micron thickness, O2 transmission rate 19000 cc/m2/24h); c) polypropylene laser-perforated films (Mach Packaging) with 8, 16 or 32 100-micron holes. Total aerobic psychrophilic, mesophilic microorganisms, Enterobacteriaceae, yeast, mould populations and in-package CO2, O2 and C2H4 were determined at each storage time. Different final gas compositions, ranging from 7.8 KPa to 17.1 KPa O2, and 12.7 KPa to 2.6 KPa CO2, were achieved with MY and micro perforated films, respectively. Differences were detected in the mesophilic, Enterobacteriaceae and yeast loads, while no difference was detected in psychrophilic microorganisms. At the end of storage, microbial load in fruits sealed with MY film was significantly lower than in those sealed with BHE and micro perforated films. Furthermore, fruits packed with micro-perforated films showed the highest microbial load. This occurrence may in part be related to in-package gas composition and in part to a continuous contamination of microorganisms through micro-holes.

  11. Genetic and Nongenetic Determinants of Cell Growth Variation Assessed by High-Throughput Microscopy

    Science.gov (United States)

    Ziv, Naomi; Siegal, Mark L.; Gresham, David

    2013-01-01

    In microbial populations, growth initiation and proliferation rates are major components of fitness and therefore likely targets of selection. We used a high-throughput microscopy assay, which enables simultaneous analysis of tens of thousands of microcolonies, to determine the sources and extent of growth rate variation in the budding yeast (Saccharomyces cerevisiae) in different glucose environments. We find that cell growth rates are regulated by the extracellular concentration of glucose as proposed by Monod (1949), but that significant heterogeneity in growth rates is observed among genetically identical individuals within an environment. Yeast strains isolated from different geographic locations and habitats differ in their growth rate responses to different glucose concentrations. Inheritance patterns suggest that the genetic determinants of growth rates in different glucose concentrations are distinct. In addition, we identified genotypes that differ in the extent of variation in growth rate within an environment despite nearly identical mean growth rates, providing evidence that alleles controlling phenotypic variability segregate in yeast populations. We find that the time to reinitiation of growth (lag) is negatively correlated with growth rate, yet this relationship is strain-dependent. Between environments, the respirative activity of individual cells negatively correlates with glucose abundance and growth rate, but within an environment respirative activity and growth rate show a positive correlation, which we propose reflects differences in protein expression capacity. Our study quantifies the sources of genetic and nongenetic variation in cell growth rates in different glucose environments with unprecedented precision, facilitating their molecular genetic dissection. PMID:23938868

  12. Microbial uptake of radiolabeled substrates: estimates of growth rates from time course measurements

    International Nuclear Information System (INIS)

    Li, W.K.W.

    1984-01-01

    The uptake of [ 3 H]glucose and a mixture of 3 H-labeled amino acids was measured, in time course fashion, in planktonic microbial assemblages of the eastern tropical Pacific Ocean. The average generation times of those portions of the assemblages able to utilize these substrates were estimated from a simple exponential growth model. Other workers have independently used this model in its integrated or differential form. A mathematical verification and an experimental demonstration of the equivalence of the two approaches are presented. A study was made of the size distribution of heterotrophic activity, using time course measurements. It was found that the size distribution and the effect of sample filtration before radiolabeling were dependent on time of incubation. In principle, it was possible to ascribe these time dependences to differences in th specific growth rate and initial standing stock of the microbial assemblages. 33 references

  13. Increase the Visibility of Microbial Growth in a Winogradsky Column by Substituting Diatomaceous Earth for Sediment

    Directory of Open Access Journals (Sweden)

    Thomas G. Benoit

    2015-02-01

    Full Text Available The difficulty students have seeing the color associated with microbial growth in a traditional Winogradsky column can be overcome by substituting diatomaceous earth (DE for sediment. Microbial growth in a DE column is visible from the early stages of ecological succession and the colors produced appear more vibrant. A flat-sided tissue culture flask can be used as a column container to provide a large surface area for observation. The enhanced visual experience provided by a DE column increases student engagement and learning. Editor's Note:The ASM advocates that students must successfully demonstrate the ability to explain and practice safe laboratory techniques. For more information, read the laboratory safety section of the ASM Curriculum Recommendations: Introductory Course in Microbiology and the Guidelines for Biosafety in Teaching Laboratories, available at www.asm.org. The Editors of JMBE recommend that adopters of the protocols included in this article follow a minimum of Biosafety Level 1 practices.

  14. Electrochemical and Chemical Complications Resulting from Yeast Extract Addition to Stimulate Microbial Growth

    Science.gov (United States)

    2016-09-22

    including strains of Saccharomyces cerevisiae grown on molasses-based media, debittered brewers yeasts (strains of Saccharo- myces cerevisiae or...RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) Technical Note: Electrochemical and Chemical Complications Resulting from Yeast Extract...Addition to Stimulate Microbial Growth Jason S. Lee‡,* and Brenda J. Little* ABSTRACT Addition of 1 g/L yeast extract (YE) to sterile, aerobic

  15. Microbial Communities: Tracing Growth Processes from Antarctic Lakes to Early Earth to Other Planets

    Science.gov (United States)

    Sumner, D. Y.

    2014-12-01

    Life in the Universe is dominated by microbes: they are numerically the most abundant cells in our bodies and in Earth's biosphere, and they are the only life that might be present elsewhere in our solar system. Life beyond our solar system could include macroscopic organisms, but everything we understand about the origin of life suggests it must start with microbes. Thus, understanding microbial ecosystems, in the absence of macroscopic organisms, is critical to understanding early life on Earth and life elsewhere in the Universe - if it exists. But what are the general principles of microbial ecology in the absence of predation? What happens when each cell is a chemical factory that can swap among metabolic processes in response to environmental and emergent cues? Geobiologists and astrobiologists are addressing these questions in diverse ways using both Earth's modern biosphere and its fossil record. Modern microbial communities in shallow, ice-covered lakes, Antarctica (Fig.), provide a model for high productivity microbial ecosystems with no to low predation. In these lakes, photosynthetic communities create macroscopic pinnacles and domes, sometime lithified into stromatolites. They provide an ecological, geochemical and morphological model for Precambrian microbial communities in low sedimentation, low current environments. Insights from these communities include new growth processes for ancient mats, especially some that grew prior to the oxidation of Earth's atmosphere. The diversity of biosignatures created in these communities also provides context for models of life under ice elsewhere in our solar system such as paleolakes on Mars and on icy moons. Results from the Mars Science Laboratory (MSL) team document formerly habitable fluvial and lacustrine environments. Lacustrine environments, in particular, are favorable for preserving biosignatures, and continued investigations by MSL will provide a deeper understanding of the duration of habitable

  16. Microbial contamination determination of Cream suit,Traditional Ice Cream and Olovia in Yasuj City

    Directory of Open Access Journals (Sweden)

    SS Khoramrooz

    2015-09-01

    Full Text Available Background & aim: Prevalence of diseases caused by consumption of contaminated food has always been a problem all over the world, and every year spent on improving the disease is costly.Cream suit, Ice cream & olowye for ingredient substance and manufacture & preservation conditional have very high possibility for contamination.The aim of this study is Microbial contamination determination of Cream suit, Traditional Ice Cream and Olovia in Yasuj City Methods: This study is randomized cross sectional study was performed on 64 samples.The samples were taken from the ice cream and confectionery shops in Yasuj city and keep on cold box then the samples were transported in sterile conditions, to the department of medical microbiology laboratory in medical university of yasuj and  microbial contamination rate evaluated by national standard method. Collected data analysed with SPSS software for data description,from central dispersion and table frequency and draw chart.  RESULTS: The survey results showed that 40% o traditional ice cream,cream suit were infected by Staph aurous, Escherichia coli and salmonella respectly (6.7,87 and 0,(50,30 and 0.(0,0 and0 present, and no seen any bacteria on olowye. Conclusion: Due to our research contamination rate traditional ice cream,cream suit and olowye were by Staph aurous, Escherichia coli and salmonella were very high . therefore using different ways to control bacterial growth especaly E.coli the mostly transmited by fecal oral including the use of healthly and safe raw material for promoting health awareness of people involved in the food preparation and production is essential.

  17. Extraction of solubles from plant biomass for use as microbial growth stimulant and methods related thereto

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ming Woei

    2015-12-08

    A method for producing a microbial growth stimulant (MGS) from a plant biomass is described. In one embodiment, an ammonium hydroxide solution is used to extract a solution of proteins and ammonia from the biomass. Some of the proteins and ammonia are separated from the extracted solution to provide the MGS solution. The removed ammonia can be recycled and the proteins are useful as animal feeds. In one embodiment, the method comprises extracting solubles from pretreated lignocellulosic biomass with a cellulase enzyme-producing growth medium (such T. reesei) in the presence of water and an aqueous extract.

  18. Effect of silver nanoparticles on growth performance, metabolism and microbial profile of broiler chickens

    DEFF Research Database (Denmark)

    Pineda, Lane Manalili; Chwalibog, André; Sawosz, Ewa

    2012-01-01

    and intestinal content were collected to evaluate the effects of AgNano on plasma concentration of immunoglobulins and the intestinal microflora, respectively. The provision of water solutions containing different concentrations of AgNano had no effect on postnatal growth performance and the energy metabolism...... (IgG) in the blood plasma of broilers supplemented with AgNano decreased at day 36 (p = 0.012). The results demonstrated that AgNano affects N utilisation and plasma IgG concentration; however, it does not influence the microbial populations in the digestive tract, the energy metabolism and growth...

  19. Compartmentalized metabolic network reconstruction of microbial communities to determine the effect of agricultural intervention on soils

    Science.gov (United States)

    Álvarez-Yela, Astrid Catalina; Gómez-Cano, Fabio; Zambrano, María Mercedes; Husserl, Johana; Danies, Giovanna; Restrepo, Silvia; González-Barrios, Andrés Fernando

    2017-01-01

    Soil microbial communities are responsible for a wide range of ecological processes and have an important economic impact in agriculture. Determining the metabolic processes performed by microbial communities is crucial for understanding and managing ecosystem properties. Metagenomic approaches allow the elucidation of the main metabolic processes that determine the performance of microbial communities under different environmental conditions and perturbations. Here we present the first compartmentalized metabolic reconstruction at a metagenomics scale of a microbial ecosystem. This systematic approach conceives a meta-organism without boundaries between individual organisms and allows the in silico evaluation of the effect of agricultural intervention on soils at a metagenomics level. To characterize the microbial ecosystems, topological properties, taxonomic and metabolic profiles, as well as a Flux Balance Analysis (FBA) were considered. Furthermore, topological and optimization algorithms were implemented to carry out the curation of the models, to ensure the continuity of the fluxes between the metabolic pathways, and to confirm the metabolite exchange between subcellular compartments. The proposed models provide specific information about ecosystems that are generally overlooked in non-compartmentalized or non-curated networks, like the influence of transport reactions in the metabolic processes, especially the important effect on mitochondrial processes, as well as provide more accurate results of the fluxes used to optimize the metabolic processes within the microbial community. PMID:28767679

  20. Compartmentalized metabolic network reconstruction of microbial communities to determine the effect of agricultural intervention on soils.

    Directory of Open Access Journals (Sweden)

    María Camila Alvarez-Silva

    Full Text Available Soil microbial communities are responsible for a wide range of ecological processes and have an important economic impact in agriculture. Determining the metabolic processes performed by microbial communities is crucial for understanding and managing ecosystem properties. Metagenomic approaches allow the elucidation of the main metabolic processes that determine the performance of microbial communities under different environmental conditions and perturbations. Here we present the first compartmentalized metabolic reconstruction at a metagenomics scale of a microbial ecosystem. This systematic approach conceives a meta-organism without boundaries between individual organisms and allows the in silico evaluation of the effect of agricultural intervention on soils at a metagenomics level. To characterize the microbial ecosystems, topological properties, taxonomic and metabolic profiles, as well as a Flux Balance Analysis (FBA were considered. Furthermore, topological and optimization algorithms were implemented to carry out the curation of the models, to ensure the continuity of the fluxes between the metabolic pathways, and to confirm the metabolite exchange between subcellular compartments. The proposed models provide specific information about ecosystems that are generally overlooked in non-compartmentalized or non-curated networks, like the influence of transport reactions in the metabolic processes, especially the important effect on mitochondrial processes, as well as provide more accurate results of the fluxes used to optimize the metabolic processes within the microbial community.

  1. Influence of mechanical disintegration on the microbial growth of aerobic sludge biomass: A comparative study of ultrasonic and shear gap homogenizers by oxygen uptake measurements.

    Science.gov (United States)

    Divyalakshmi, P; Murugan, D; Sivarajan, M; Saravanan, P; Lajapathi Rai, C

    2015-11-01

    Wastewater treatment plant incorporates physical, chemical and biological processes to treat and remove the contaminants. The main drawback of conventional activated sludge process is the huge production of excess sludge, which is an unavoidable byproduct. The treatment and disposal of excess sludge costs about 60% of the total operating cost. The ideal way to reduce excess sludge production during wastewater treatment is by preventing biomass formation within the aerobic treatment train rather than post treatment of the generated sludge. In the present investigation two different mechanical devices namely, Ultrasonic and Shear Gap homogenizers have been employed to disintegrate the aerobic biomass. This study is intended to restrict the multiplication of microbial biomass and at the same time degrade the organics present in wastewater by increasing the oxidative capacity of microorganisms. The disintegrability on biomass was determined by biochemical methods. Degree of inactivation provides the information on inability of microorganisms to consume oxygen upon disruption. The soluble COD quantifies the extent of release of intra cellular compounds. The participation of disintegrated microorganism in wastewater treatment process was carried out in two identical respirometeric reactors. The results show that Ultrasonic homogenizer is very effective in the disruption of microorganisms leading to a maximum microbial growth reduction of 27%. On the other hand, Shear gap homogenizer does not favor the sludge growth reduction rather it facilitates the growth. This study also shows that for better microbial growth reduction, floc size reduction alone is not sufficient but also microbial disruption is essential. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Use of an uncertainty analysis for genome-scale models as a prediction tool for microbial growth processes in subsurface environments.

    Science.gov (United States)

    Klier, Christine

    2012-03-06

    The integration of genome-scale, constraint-based models of microbial cell function into simulations of contaminant transport and fate in complex groundwater systems is a promising approach to help characterize the metabolic activities of microorganisms in natural environments. In constraint-based modeling, the specific uptake flux rates of external metabolites are usually determined by Michaelis-Menten kinetic theory. However, extensive data sets based on experimentally measured values are not always available. In this study, a genome-scale model of Pseudomonas putida was used to study the key issue of uncertainty arising from the parametrization of the influx of two growth-limiting substrates: oxygen and toluene. The results showed that simulated growth rates are highly sensitive to substrate affinity constants and that uncertainties in specific substrate uptake rates have a significant influence on the variability of simulated microbial growth. Michaelis-Menten kinetic theory does not, therefore, seem to be appropriate for descriptions of substrate uptake processes in the genome-scale model of P. putida. Microbial growth rates of P. putida in subsurface environments can only be accurately predicted if the processes of complex substrate transport and microbial uptake regulation are sufficiently understood in natural environments and if data-driven uptake flux constraints can be applied.

  3. Effect of Chitosan Coating Containing Active Agents on Microbial Growth, Rancidity and Moisture Loss of Meatball During Storage

    OpenAIRE

    Pranoto, Yudi; Rakshit, Sudip Kumar

    2008-01-01

    Edible coatings based on chitosan were applied on meatball product in order to preserve quality during storages atambient and refrigeration temperatures. To improve its efficacy, chitosan coatings were incorporated with garlic oil0.2%, potassium sorbate 0.1 % and nisin 51,000 IU. The qualities of meatball assessed were total microbial growth, TBA value and percentage of moisture loss. All chitosan coatings suppressed microbial growth in meatball and strong- ly revealed when stored at refriger...

  4. Biohydrogen production in the suspended and attached microbial growth systems from waste pastry hydrolysate.

    Science.gov (United States)

    Han, Wei; Hu, Yunyi; Li, Shiyi; Li, Feifei; Tang, Junhong

    2016-10-01

    Waste pastry was hydrolyzed by glucoamylase and protease which were obtained from solid state fermentation of Aspergillus awamori and Aspergillus oryzae to produce waste pastry hydrolysate. Then, the effects of hydraulic retention times (HRTs) (4-12h) on hydrogen production rate (HPR) in the suspended microbial growth system (continuous stirred tank reactor, CSTR) and attached microbial growth system (continuous mixed immobilized sludge reactor, CMISR) from waste pastry hydrolysate were investigated. The maximum HPRs of CSTR (201.8mL/(h·L)) and CMISR (255.3mL/(h·L)) were obtained at HRT of 6h and 4h, respectively. The first-order reaction could be used to describe the enzymatic hydrolysis of waste pastry. The carbon content of the waste pastry remained 22.8% in the undigested waste pastry and consumed 77.2% for carbon dioxide and soluble microbial products. To our knowledge, this is the first study which reports biohydrogen production from waste pastry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Quantum dots conjugated zinc oxide nanosheets: Impeder of microbial growth and biofilm

    Science.gov (United States)

    Patil, Rajendra; Gholap, Haribhau; Warule, Sambhaji; Banpurkar, Arun; Kulkarni, Gauri; Gade, Wasudeo

    2015-01-01

    The grieving problem of the 21st century has been the antimicrobial resistance in pathogenic microorganisms to conventional antibiotics. Therefore, developments of novel antibacterial materials which effectively inhibit or kill such resistant microorganisms have become the need of the hour. In the present study, we communicate the synthesis of quantum dots conjugated zinc oxide nanostructures (ZnO/CdTe) as an impeder of microbial growth and biofilm. The as-synthesized nanostructures were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy. The growth impedance property of ZnO and ZnO/CdTe on Gram positive organism, Bacillus subtilis NCIM 2063 and Gram negative, Escherichia coli NCIM 2931 and biofilm impedance activity in Pseudomonas aeruginosa O1 was found to occur due to photocatalytical action on the cell biofilm surfaces. The impedance in microbial growth and biofilm formation was further supported by ruptured appearances of cells and dettrered biofilm under field emission scanning electron and confocal laser scanning microscope. The ZnO/CdTe nanostructures array synthesized by hydrothermal method has an advantage of low growth temperature, and opportunity to fabricate inexpensive material for nano-biotechnological applications.

  6. Microbial changes and growth of Listeria monocytogenes during chilled storage of brined shrimp ( Pandalus borealis )

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Kjeldgaard, J.; Modberg, A.

    2008-01-01

    Thirteen storage trials and ten challenge tests were carried out to examine microbial changes, spoilage and the potential growth of Listeria monocytogenes in brined shrimp (Pandalus borealis). Shrimp in brine as well as brined and drained shrimp in modified atmosphere packaging (MAP) were produced...... and lactic acids were studied. Furthermore, the effect of adding diacetate to brined shrimp was evaluated. A single batch of cooked and peeled shrimp was used to study both industrially and manually processed brined shrimp with respect to the effect of process hygiene on microbial changes and the shelf life...... of products. Concentrations of microorganisms on newly produced brined shrimp from an industrial scale processing line were 1.0-2.3 log (CFU g(-1)) higher than comparable concentrations in manually processed samples. This resulted in a substantially shorter shelf life and a more diverse spoilage microflora...

  7. Effect of Nisin's Controlled Release on Microbial Growth as Modeled for Micrococcus luteus.

    Science.gov (United States)

    Balasubramanian, Aishwarya; Lee, Dong Sun; Chikindas, Michael L; Yam, Kit L

    2011-06-01

    The need for safe food products has motivated food scientists and industry to find novel technologies for antimicrobial delivery for improving food safety and quality. Controlled release packaging is a novel technology that uses the package to deliver antimicrobials in a controlled manner and sustain antimicrobial stress on the targeted microorganism over the required shelf life. This work studied the effect of controlled release of nisin to inhibit growth of Micrococcus luteus (a model microorganism) using a computerized syringe pump system to mimic the release of nisin from packaging films which was characterized by an initially fast rate and a slower rate as time progressed. The results show that controlled release of nisin was strikingly more effective than instantly added ("formulated") nisin. While instant addition experiments achieved microbial inhibition only at the beginning, controlled release experiments achieved complete microbial inhibition for a longer time, even when as little as 15% of the amount of nisin was used as compared to instant addition.

  8. Bifurcations of a periodically forced microbial continuous culture model with restrained growth rate

    Science.gov (United States)

    Ren, Jingli; Yuan, Qigang

    2017-08-01

    A three dimensional microbial continuous culture model with a restrained microbial growth rate is studied in this paper. Two types of dilution rates are considered to investigate the dynamic behaviors of the model. For the unforced system, fold bifurcation and Hopf bifurcation are detected, and numerical simulations reveal that the system undergoes degenerate Hopf bifurcation. When the system is periodically forced, bifurcation diagrams for periodic solutions of period-one and period-two are given by researching the Poincaré map, corresponding to different bifurcation cases in the unforced system. Stable and unstable quasiperiodic solutions are obtained by Neimark-Sacker bifurcation with different parameter values. Periodic solutions of various periods can occur or disappear and even change their stability, when the Poincaré map of the forced system undergoes Neimark-Sacker bifurcation, flip bifurcation, and fold bifurcation. Chaotic attractors generated by a cascade of period doublings and some phase portraits are given at last.

  9. Determinants of Growth Hormone Resistance in Malnutrition

    Science.gov (United States)

    Fazeli, Pouneh K.; Klibanski, Anne

    2014-01-01

    States of under-nutrition are characterized by growth hormone resistance. Decreased total energy intake, as well as isolated protein-calorie malnutrition and isolated nutrient deficiencies result in elevated growth hormone levels and low levels of IGF-I. We review various states of malnutrition and a disease state characterized by chronic under-nutrition -- anorexia nervosa -- and discuss possible mechanisms contributing to the state of growth hormone resistance, including FGF-21 and SIRT1. We conclude by examining the hypothesis that growth hormone resistance is an adaptive response to states of under-nutrition, in order to maintain euglycemia and preserve energy. PMID:24363451

  10. Microbial Communities and Their Predicted Metabolic Functions in Growth Laminae of a Unique Large Conical Mat from Lake Untersee, East Antarctica

    Directory of Open Access Journals (Sweden)

    Hyunmin Koo

    2017-08-01

    Full Text Available In this study, we report the distribution of microbial taxa and their predicted metabolic functions observed in the top (U1, middle (U2, and inner (U3 decadal growth laminae of a unique large conical microbial mat from perennially ice-covered Lake Untersee of East Antarctica, using NextGen sequencing of the 16S rRNA gene and bioinformatics tools. The results showed that the U1 lamina was dominated by cyanobacteria, specifically Phormidium sp., Leptolyngbya sp., and Pseudanabaena sp. The U2 and U3 laminae had high abundances of Actinobacteria, Verrucomicrobia, Proteobacteria, and Bacteroidetes. Closely related taxa within each abundant bacterial taxon found in each lamina were further differentiated at the highest taxonomic resolution using the oligotyping method. PICRUSt analysis, which determines predicted KEGG functional categories from the gene contents and abundances among microbial communities, revealed a high number of sequences belonging to carbon fixation, energy metabolism, cyanophycin, chlorophyll, and photosynthesis proteins in the U1 lamina. The functional predictions of the microbial communities in U2 and U3 represented signal transduction, membrane transport, zinc transport and amino acid-, carbohydrate-, and arsenic- metabolisms. The Nearest Sequenced Taxon Index (NSTI values processed through PICRUSt were 0.10, 0.13, and 0.11 for U1, U2, and U3 laminae, respectively. These values indicated a close correspondence with the reference microbial genome database, implying high confidence in the predicted metabolic functions of the microbial communities in each lamina. The distribution of microbial taxa observed in each lamina and their predicted metabolic functions provides additional insight into the complex microbial ecosystem at Lake Untersee, and lays the foundation for studies that will enhance our understanding of the mechanisms responsible for the formation of these unique mat structures and their evolutionary significance.

  11. Biomechanical ordering and buckling due to microbial growth confined at oil-water interfaces

    Science.gov (United States)

    Juarez, Gabriel; Stocker, Roman

    2015-11-01

    Bacteria are unicellular organisms that often exist as densely populated, surface-associated communities. Bacteria are also environmental colloids and spontaneously attach and self-assemble at liquid-liquid interfaces. Here, we present results on the growth dynamics of individual rod-shaped bacteria confined to finite oil-water interfaces of varying curvature. Through experiments using microfluidic chambers and time-lapse microscopy, we study the formation of macroscopic structures observed as adsorbed bacteria grow, divide, and self-assemble in a nematic phase due to biomechanical interactions. The continued growth at the interface leads to a jammed monolayer of cells, which then causes the interface to buckle and undergo large deformations including wrinkling and tubulation. These observations highlight the interplay between physical environment, such as confinement and interface curvature, and active biological processes, such as growth, at the scale of individual agents and shape our understanding of macroscale processes such as microbial degradation of oil in the ocean.

  12. Study of the Efficacy of Real Time-PCR Method for Amikacin Determination Using Microbial Assay

    Directory of Open Access Journals (Sweden)

    Farzaneh Lotfipour

    2015-06-01

    Full Text Available Purpose: Microbial assay is used to determine the potency of antibiotics and vitamins. In spite of its advantages like simplicity and easiness, and to reveal the slight changes in the molecules, the microbial assay suffers from significant limitations; these methods are of lower specificity, accuracy and sensitivity. The objective of the present study is to evaluate the efficacy of real time-PCR technique in comparison with turbidimetric method for microbial assay of amikacin. Methods: Microbial determination of amikacin by turbidimetric method was performed according to USP. Also amikacin concentrations were determined by microbial assay using taq-man quantitative PCR method. Standard curves in different concentration for both methods were plotted and method validation parameters of linearity, precision and accuracy were calculated using statistical procedures. Results: The RT-PCR method was linear in the wider concentration range (5.12 – 38.08 for RT-PCR versus 8.00 – 30.47 for turbidimetric method with a better correlation coefficient (0.976 for RT-PCR versus 0.958 for turbidimetric method. RT-PCR method with LOQ of 5.12 ng/ml was more sensitive than turbidimetric method with LOQ of 8.00 ng/ml and the former could detect and quantify low concentrations of amikacin. The results of accuracy and precision evaluation showed that the RT-PCR method was accurate and precise in all of the tested concentration. Conclusion: The RT-PCR method described here provided an accurate and precise technique for measurement of amikacin potency and it can be a candidate for microbial determination of the antibiotics with the same test organism.

  13. PLANT GROWTH-PROMOTING MICROBIAL INOCULANT FOR Schizolobium parahyba pv. parahyba

    Directory of Open Access Journals (Sweden)

    Priscila Jane Romano de Oliveira Gonçalves

    2015-08-01

    Full Text Available ABSTRACTSchizolobium parahyba pv. amazonicum (Huber ex Ducke Barneby (paricá occurs naturally in the Amazon and is significant commercial importance due to its rapid growth and excellent performance on cropping systems. The aim of this paper was to evaluate a microbial inoculants such as arbuscular mycorrhiza fungi (AMF and Rhizobium sp. that promote plant growth. The inocula was 10 g of root colonized and spores of Glomus clarum and/or 1 mL of cell suspension (107 CFU/mL of Rhizobium sp. and/or 100 g of chemical fertilizer NPK 20-05-20 per planting hole. The experimental design was complete randomized blocks with five replications and eight treatments (n = 800. Plant height, stem diameter and plant survival were measured. The results were tested for normality and homogeneity of variances and analyzed by ANOVA and Tukey test (p < 0.05. Rhizobium sp and AM fungi showed no effect on plant growth. Environmental factors probably influenced the effectiveness of symbiosis of both microorganisms and plant growth. The chemical fertilizer increased S. parahyba growth. During the first 120 days plants suffered with drought and frost, and at 180 days plants inoculated with microorganism plus chemical fertilizer showed higher survival when compared with control. The results showed that the microbial inoculants used showed an important role on plant survival after high stress conditions, but not in plant growth. Also was concluded that the planting time should be between November to December to avoid the presence of young plants during winter time that is dry and cold.

  14. Secreted pitfall-trap fluid of carnivorous Nepenthes plants is unsuitable for microbial growth.

    Science.gov (United States)

    Buch, Franziska; Rott, Matthias; Rottloff, Sandy; Paetz, Christian; Hilke, Ines; Raessler, Michael; Mithöfer, Axel

    2013-03-01

    Carnivorous plants of the genus Nepenthes possess modified leaves that form pitfall traps in order to capture prey, mainly arthropods, to make additional nutrients available for the plant. These pitchers contain a digestive fluid due to the presence of hydrolytic enzymes. In this study, the composition of the digestive fluid was further analysed with regard to mineral nutrients and low molecular-weight compounds. A potential contribution of microbes to the composition of pitcher fluid was investigated. Fluids from closed pitchers were harvested and analysed for mineral nutrients using analytical techniques based on ion-chromatography and inductively coupled plasma-optical emission spectroscopy. Secondary metabolites were identified by a combination of LC-MS and NMR. The presence of bacteria in the pitcher fluid was investigated by PCR of 16S-rRNA genes. Growth analyses of bacteria and yeast were performed in vitro with harvested pitcher fluid and in vivo within pitchers with injected microbes. The pitcher fluid from closed pitchers was found to be primarily an approx. 25-mm KCl solution, which is free of bacteria and unsuitable for microbial growth probably due to the lack of essential mineral nutrients such as phosphate and inorganic nitrogen. The fluid also contained antimicrobial naphthoquinones, plumbagin and 7-methyl-juglone, and defensive proteins such as the thaumatin-like protein. Challenging with bacteria or yeast caused bactericide as well as fungistatic properties in the fluid. Our results reveal that Nepenthes pitcher fluids represent a dynamic system that is able to react to the presence of microbes. The secreted liquid of closed and freshly opened Nepenthes pitchers is exclusively plant-derived. It is unsuitable to serve as an environment for microbial growth. Thus, Nepenthes plants can avoid and control, at least to some extent, the microbial colonization of their pitfall traps and, thereby, reduce the need to vie with microbes for the prey

  15. Alignment of microbial fitness with engineered product formation: obligatory coupling between acetate production and photoautotrophic growth.

    Science.gov (United States)

    Du, Wei; Jongbloets, Joeri A; van Boxtel, Coco; Pineda Hernández, Hugo; Lips, David; Oliver, Brett G; Hellingwerf, Klaas J; Branco Dos Santos, Filipe

    2018-01-01

    Microbial bioengineering has the potential to become a key contributor to the future development of human society by providing sustainable, novel, and cost-effective production pipelines. However, the sustained productivity of genetically engineered strains is often a challenge, as spontaneous non-producing mutants tend to grow faster and take over the population. Novel strategies to prevent this issue of strain instability are urgently needed. In this study, we propose a novel strategy applicable to all microbial production systems for which a genome-scale metabolic model is available that aligns the production of native metabolites to the formation of biomass. Based on well-established constraint-based analysis techniques such as OptKnock and FVA, we developed an in silico pipeline-FRUITS-that specifically 'Finds Reactions Usable in Tapping Side-products'. It analyses a metabolic network to identify compounds produced in anabolism that are suitable to be coupled to growth by deletion of their re-utilization pathway(s), and computes their respective biomass and product formation rates. When applied to Synechocystis sp. PCC6803, a model cyanobacterium explored for sustainable bioproduction, a total of nine target metabolites were identified. We tested our approach for one of these compounds, acetate, which is used in a wide range of industrial applications. The model-guided engineered strain shows an obligatory coupling between acetate production and photoautotrophic growth as predicted. Furthermore, the stability of acetate productivity in this strain was confirmed by performing prolonged turbidostat cultivations. This work demonstrates a novel approach to stabilize the production of target compounds in cyanobacteria that culminated in the first report of a photoautotrophic growth-coupled cell factory. The method developed is generic and can easily be extended to any other modeled microbial production system.

  16. Determination of Antibiotic Residues in Milk by Microbial Inhibitory Tests

    Directory of Open Access Journals (Sweden)

    Juščáková D.

    2017-09-01

    Full Text Available Undesirable substances enter the organism of animals mostly via feed, water or veterinary medicines and their residues pass subsequently into the products of animal origin. In dairy cows, sheep and goats these residues are eliminated particularly in milk. Milk intended for human consumption must comply with safety criteria also with respect to residues of antibiotics. The aim of this study was to determine the presence or absence of antibiotic residues in the milk using the tests Milchtest and Premi®Test. While the Milchtest was developed for the determination of antibiotic residues in cow, sheep and goat milk, the Premi®Test is intended for the determination of antibiotic residues in meat juice, liver, kidneys, fish, eggs and in the urine of animals treated with antibiotics. As examined matrices, we used 45 samples of raw cow’s milk collected at 3 agricultural farms and 10 samples of milk offered to consumers at grocery stores. When using the Milchtest, 8 samples tested positive and 10 provided dubious results while testing with the Premi®Test showed that only 6 samples were positive for antibiotics. Comparison of the results confirmed a higher detection sensitivity of Milchtest reflected in higher numbers of positive samples and the detection of dubious results in samples of raw cow’s milk. However, it should be noted that even the Premi®Test, although not intended preferably for the determination of antibiotics in milk, can be used, if needed, for the preliminary screening of antibiotic residues in such a matrix.

  17. Changes in Microbial Energy Metabolism Measured by Nanocalorimetry during Growth Phase Transitions

    Science.gov (United States)

    Robador, Alberto; LaRowe, Douglas E.; Finkel, Steven E.; Amend, Jan P.; Nealson, Kenneth H.

    2018-01-01

    Calorimetric measurements of the change in heat due to microbial metabolic activity convey information about the kinetics, as well as the thermodynamics, of all chemical reactions taking place in a cell. Calorimetric measurements of heat production made on bacterial cultures have recorded the energy yields of all co-occurring microbial metabolic reactions, but this is a complex, composite signal that is difficult to interpret. Here we show that nanocalorimetry can be used in combination with enumeration of viable cell counts, oxygen consumption rates, cellular protein content, and thermodynamic calculations to assess catabolic rates of an isolate of Shewanella oneidensis MR-1 and infer what fraction of the chemical energy is assimilated by the culture into biomass and what fraction is dissipated in the form of heat under different limiting conditions. In particular, our results demonstrate that catabolic rates are not necessarily coupled to rates of cell division, but rather, to physiological rearrangements of S. oneidensis MR-1 upon growth phase transitions. In addition, we conclude that the heat released by growing microorganisms can be measured in order to understand the physiochemical nature of the energy transformation and dissipation associated with microbial metabolic activity in conditions approaching those found in natural systems. PMID:29449836

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

    Science.gov (United States)

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

    2013-04-09

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

  19. The effect of concentrating of whitewater to the microbial growth in papermachine; Paperikoneen kiertovesien konsentroitumisen vaikutus mikrobien kasvuun - MPKT 03

    Energy Technology Data Exchange (ETDEWEB)

    Yloestalo, T [Helsinki Univ. of Technology, Otaniemi (Finland)

    1999-12-31

    The closing of the whitewater cycle increases the amount of nutrients available for the micro-organisms living in a papermachine. The microbial flora in papermachines can vary significantly. The type and concentration of nutrients and the operating conditions of the papermachine (for example pH and temperature) affect the type of microbes that may live there. Strong microbial contamination has negative impact to the quality of the products and the operation of the papermachine. In this project microbes isolated from papermachines are cultivated in different concentrations of whitewater and with different pH and temperature values. The cultivations of microbes and modeling of the microbial growth are used for finding out how the closing of the whitewater cycle affects the microbial growth in papermachines. (orig.)

  20. The effect of concentrating of whitewater to the microbial growth in papermachine; Paperikoneen kiertovesien konsentroitumisen vaikutus mikrobien kasvuun - MPKT 03

    Energy Technology Data Exchange (ETDEWEB)

    Yloestalo, T. [Helsinki Univ. of Technology, Otaniemi (Finland)

    1998-12-31

    The closing of the whitewater cycle increases the amount of nutrients available for the micro-organisms living in a papermachine. The microbial flora in papermachines can vary significantly. The type and concentration of nutrients and the operating conditions of the papermachine (for example pH and temperature) affect the type of microbes that may live there. Strong microbial contamination has negative impact to the quality of the products and the operation of the papermachine. In this project microbes isolated from papermachines are cultivated in different concentrations of whitewater and with different pH and temperature values. The cultivations of microbes and modeling of the microbial growth are used for finding out how the closing of the whitewater cycle affects the microbial growth in papermachines. (orig.)

  1. Carbon stabilization and microbial growth in acidic mine soils after addition of different amendments for soil reclamation

    Science.gov (United States)

    Zornoza, Raúl; Acosta, Jose; Ángeles Muñoz, María; Martínez-Martínez, Silvia; Faz, Ángel; Bååth, Erland

    2016-04-01

    The extreme soil conditions in metalliferous mine soils have a negative influence on soil biological activity and therefore on soil carbon estabilization. Therefore, amendments are used to increase organic carbon content and activate microbial communities. In order to elucidate some of the factors controlling soil organic carbon stabilization in reclaimed acidic mine soils and its interrelationship with microbial growth and community structure, we performed an incubation experiment with four amendments: pig slurry (PS), pig manure (PM) and biochar (BC), applied with and without marble waste (MW; CaCO3). Results showed that PM and BC (alone or together with MW) contributed to an important increment in recalcitrant organic C, C/N ratio and aggregate stability. Bacterial and fungal growths were highly dependent on pH and labile organic C. PS supported the highest microbial growth; applied alone it stimulated fungal growth, and applied with MW it stimulated bacterial growth. BC promoted the lowest microbial growth, especially for fungi, with no significant increase in fungal biomass. MW+BC increased bacterial growth up to values similar to PM and MW+PM, suggesting that part of the biochar was degraded, at least in short-term mainly by bacteria rather than fungi. PM, MW+PS and MW+PM supported the highest microbial biomass and a similar community structure, related with the presence of high organic C and high pH, with immobilization of metals and increased soil quality. BC contributed to improved soil structure, increased recalcitrant organic C, and decreased metal mobility, with low stimulation of microbial growth.

  2. The Growth Rate and Efficiency of Rumen Microbial Protein Digestion of Red Clover Silage (Trifolium pratense cv. Sabatron)

    International Nuclear Information System (INIS)

    Asih Kurniawati

    2004-01-01

    (Trifolium pratense cv. Sabatron). Red clover silage supplemented with different level of carbohydrates has been examined using the in-vitro gas production technique. Cumulative gas production, hydro.gen sulfite production, and ammonia was followed and used as indicators of microbial growth rate and extent of protein degradation. Microbial nitrogen production, VFA, and efficiency microbial production was used as indicator of nitrogen use efficiency. 15 N was used as a microbial marker to estimate the amount of nitrogen incorporation into microbial protein. Supplementation of Red clover with increasing 5 levels; 0 g; 0.625 g; 0.15 g; 0.225 g and 0.3 g of maize starch led to graded increase in microbial growth and protein degradation. This was reflected in the increasing gas production and the accumulation of hydrogen sulfite. Diurnal change in ammonia production reflected the microbial utilization of ammonia for protein synthesis. Protein microbe (P<0.001) as VFA (P<0.001) increased due to carbohydrate addition as well as utilization of nitrogen (P<0.001). There was also the efficiency of nitrogen utilization which increased significantly. This result suggested that energy supply can increased efficiency of nitrogen use in the rumen and may reduce nitrogen losses into the environment. (author)

  3. Tibia mineralization of chickens determined to meat production using a microbial phytase

    Directory of Open Access Journals (Sweden)

    Mária Angelovičová

    2018-02-01

    Full Text Available The target of the research was 6-phytase of microbial origin. It was used in feed mixtures for chickens determined to meat production. Its effect has been studied in relation to the tibia mineralization by calcium, phosphorus and magnesium. 6-phytase is a product of Aspergillus oryzae. That was obtained by means of biotechnological processes of production of commercially available enzymes. It was incorporated in the feed mixtures 0.1%. In a 38-day feeding trial, 300 one-day-old, as hatched, Cobb 500 chickens determined to meat production (100 birds per group were fed on one concentrations of dietary non-phytate phosphorus (2.32, 2.31 g.kg-1, respectively and supplemental microbial phytase (0 and 500   FTU.kg-1 feed mixtures. Control group was used to compare the results and control feed mixtures contained 4.5 g.kg-1 without microbial phytase. At days 40 it was selected 6 birds in every group, which were slaughter in accordance with the principles of welfare. Left tibias of every bird were used to determination of calcium, phosphorus and magnesium contents. According to in vivo, it was found that the addition of microbial phytase to reduced dietary non-phytate phosphorus increased concentrations of calcium (Ca, phosphorus (P and magnesium (Mg in tibia. The differences among groups were statistically significant (p <0.05. It was concluded that reducing of dietary non-phytate phosphorus on the 2.32, 2.31 g.kg-1, respectively, by monocalcium phosphate and microbial phytase supplementation in feed mixtures facilitated tibia mineralization at chicken determined to meat production. Normal 0 21 false false false EN-GB X-NONE X-NONE

  4. Detection of irradiation of strawberries by determining their microbial characteristics

    International Nuclear Information System (INIS)

    Tamminga, S.K.; Beumer, R.R.; Kampelmacher, E.H.

    1978-01-01

    A system was elaborated to determine whether strawberries have been irradiated, using 3 criteria, namely the number of Enterobacteriaceae, the percentage of yeasts on total microflora (or total absence of microorganisms) and the number of Pseudomonas. The higher the numbers of Enterobacteriaceae and/or Pseudomonas, the lower the probability that the strawberries have been irradiated. The higher the yeast percentage, the more the conclusion is justified that irradiation has taken place. The same holds true for total absence of microorganisms. By combining results for the 3 criteria an identification scheme was drawn up that would have led to 189 correct decisions (92.2%) on 205 samples (102 irradiated with 200krad, 103 unirradiated). In only 3 samples (1.5%) the combination of properties resembled that generally shown by the opposite group in such a way that they would have been classified in the wrong category. Some combinations of results for the 3 criteria were found in about equal numbers for both irradiated and unirradiated samples. These samples and others showing contradictory results, totalling 13 samples (6.3%), had to be placed in a separate 'intermediate' category, about which no opinion could be given. The only possibility in such cases is to investigate new samples. Sixty of the samples were investigated without the investigators knowing whether the samples had been irradiated; 56 of them would have been classified in the right category with the help of the scheme made up using the previous data; the remaining 4 had to be classified in the intermediate category. (author)

  5. A comparison of various Gibbs energy dissipation correlations for predicting microbial growth yields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.-S. [Laboratory of Chemical and Biochemical Engineering, Swiss Federal Institute of Technology, EPFL, CH-1015 Lausanne (Switzerland); Vojinovic, V. [Laboratory of Chemical and Biochemical Engineering, Swiss Federal Institute of Technology, EPFL, CH-1015 Lausanne (Switzerland); Patino, R. [Cinvestav-Merida, Departamento de Fisica Aplicada, Km. 6 carretera antigua a Progreso, AP 73 Cordemex, 97310 Merida, Yucatan (Mexico); Maskow, Th. [UFZ Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, D-04318 Leipzig (Germany); Stockar, U. von [Laboratory of Chemical and Biochemical Engineering, Swiss Federal Institute of Technology, EPFL, CH-1015 Lausanne (Switzerland)]. E-mail: urs.vonStockar@epfl.ch

    2007-06-25

    Thermodynamic analysis may be applied in order to predict microbial growth yields roughly, based on an empirical correlation of the Gibbs energy of the overall growth reaction or Gibbs energy dissipation. Due to the well-known trade-off between high biomass yield and high Gibbs energy dissipation necessary for fast growth, an optimal range of Gibbs energy dissipation exists and it can be correlated to physical characteristics of the growth substrates. A database previously available in the literature has been extended significantly in order to test such correlations. An analysis of the relationship between biomass yield and Gibbs energy dissipation reveals that one does not need a very precise estimation of the latter to predict the former roughly. Approximating the Gibbs energy dissipation with a constant universal value of -500 kJ C-mol{sup -1} of dry biomass grown predicts many experimental growth yields nearly as well as a carefully designed, complex correlation available from the literature, even though a number of predictions are grossly out of range. A new correlation for Gibbs energy dissipation is proposed which is just as accurate as the complex literature correlation despite its dramatically simpler structure.

  6. A comparison of various Gibbs energy dissipation correlations for predicting microbial growth yields

    International Nuclear Information System (INIS)

    Liu, J.-S.; Vojinovic, V.; Patino, R.; Maskow, Th.; Stockar, U. von

    2007-01-01

    Thermodynamic analysis may be applied in order to predict microbial growth yields roughly, based on an empirical correlation of the Gibbs energy of the overall growth reaction or Gibbs energy dissipation. Due to the well-known trade-off between high biomass yield and high Gibbs energy dissipation necessary for fast growth, an optimal range of Gibbs energy dissipation exists and it can be correlated to physical characteristics of the growth substrates. A database previously available in the literature has been extended significantly in order to test such correlations. An analysis of the relationship between biomass yield and Gibbs energy dissipation reveals that one does not need a very precise estimation of the latter to predict the former roughly. Approximating the Gibbs energy dissipation with a constant universal value of -500 kJ C-mol -1 of dry biomass grown predicts many experimental growth yields nearly as well as a carefully designed, complex correlation available from the literature, even though a number of predictions are grossly out of range. A new correlation for Gibbs energy dissipation is proposed which is just as accurate as the complex literature correlation despite its dramatically simpler structure

  7. Quantum dots conjugated zinc oxide nanosheets: Impeder of microbial growth and biofilm

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Rajendra [Department of Biotechnology, Savitribai Phule Pune University, Pune 411007 (India); Gholap, Haribhau, E-mail: haribhau.gholap@fergusson.edu [Department of Physics, Fergusson College, Pune 411004 (India); Warule, Sambhaji [Department of Physics, Nowrosjee Wadia College, Pune 411001 (India); Banpurkar, Arun; Kulkarni, Gauri [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Gade, Wasudeo, E-mail: wngade@unipune.ac.in [Department of Biotechnology, Savitribai Phule Pune University, Pune 411007 (India)

    2015-01-30

    Graphical abstract: The visible light upon incident on ZnO/CdTe initiate the phenomenon of photocatalytical impedance of biofilm. - Highlights: • Synthesis of efficient light photocatalyst ZnO/CdTe nanostructures by hydrothermal method. • ZnO/CdTe nanostructures show a good antibacterial activity by action on cell membrane. • ZnO/CdTe nanostructures show a good antibiofilm activity, and also act on the cells inside the biofilm. - Abstract: The grieving problem of the 21st century has been the antimicrobial resistance in pathogenic microorganisms to conventional antibiotics. Therefore, developments of novel antibacterial materials which effectively inhibit or kill such resistant microorganisms have become the need of the hour. In the present study, we communicate the synthesis of quantum dots conjugated zinc oxide nanostructures (ZnO/CdTe) as an impeder of microbial growth and biofilm. The as-synthesized nanostructures were characterized by X-ray diffraction, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy. The growth impedance property of ZnO and ZnO/CdTe on Gram positive organism, Bacillus subtilis NCIM 2063 and Gram negative, Escherichia coli NCIM 2931 and biofilm impedance activity in Pseudomonas aeruginosa O1 was found to occur due to photocatalytical action on the cell biofilm surfaces. The impedance in microbial growth and biofilm formation was further supported by ruptured appearances of cells and dettrered biofilm under field emission scanning electron and confocal laser scanning microscope. The ZnO/CdTe nanostructures array synthesized by hydrothermal method has an advantage of low growth temperature, and opportunity to fabricate inexpensive material for nano-biotechnological applications.

  8. Quantum dots conjugated zinc oxide nanosheets: Impeder of microbial growth and biofilm

    International Nuclear Information System (INIS)

    Patil, Rajendra; Gholap, Haribhau; Warule, Sambhaji; Banpurkar, Arun; Kulkarni, Gauri; Gade, Wasudeo

    2015-01-01

    Graphical abstract: The visible light upon incident on ZnO/CdTe initiate the phenomenon of photocatalytical impedance of biofilm. - Highlights: • Synthesis of efficient light photocatalyst ZnO/CdTe nanostructures by hydrothermal method. • ZnO/CdTe nanostructures show a good antibacterial activity by action on cell membrane. • ZnO/CdTe nanostructures show a good antibiofilm activity, and also act on the cells inside the biofilm. - Abstract: The grieving problem of the 21st century has been the antimicrobial resistance in pathogenic microorganisms to conventional antibiotics. Therefore, developments of novel antibacterial materials which effectively inhibit or kill such resistant microorganisms have become the need of the hour. In the present study, we communicate the synthesis of quantum dots conjugated zinc oxide nanostructures (ZnO/CdTe) as an impeder of microbial growth and biofilm. The as-synthesized nanostructures were characterized by X-ray diffraction, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy. The growth impedance property of ZnO and ZnO/CdTe on Gram positive organism, Bacillus subtilis NCIM 2063 and Gram negative, Escherichia coli NCIM 2931 and biofilm impedance activity in Pseudomonas aeruginosa O1 was found to occur due to photocatalytical action on the cell biofilm surfaces. The impedance in microbial growth and biofilm formation was further supported by ruptured appearances of cells and dettrered biofilm under field emission scanning electron and confocal laser scanning microscope. The ZnO/CdTe nanostructures array synthesized by hydrothermal method has an advantage of low growth temperature, and opportunity to fabricate inexpensive material for nano-biotechnological applications

  9. Preventing microbial growth on pall-rings when upgrading biogas using absorption with water wash

    Energy Technology Data Exchange (ETDEWEB)

    Haakansson, Anna

    2006-07-15

    For produced biogas to be usable as vehicle fuel it has to be upgraded to a higher energy content. This is accomplished by elevation of the methane concentration through removal of carbon dioxide. Absorption with water wash is the most common upgrading method used in Sweden today. The upgrading technique is based on the fact that carbon dioxide is more soluble in water than methane. Upgrading plants that utilises this method have problems with microbial growth in the system. This growth eventually leads to a stop in operation due to the gradually drop in upgrading capacity. The aim of this thesis were to evaluate the possibility to through some kind of water treatment maintain an acceptable level of growth or altogether prevent it in order to maintain an acceptable process capacity and thereby avoid the need to clean. Through collection of literature the implementation possibilities were evaluated with regard to efficiency, economic sustainability and if there would be a release of any harmful substances. In order to prevent the microbial growth in the columns the treatment should either focus on removing microorganisms or limit the accessible nutrients. For the single pass system it is concluded that the treatment should reduce the biofilm formation and be employed in an intermittent way. Among the evaluated treatments focusing on the reduction of microorganisms the addition of peracetic acid seems to be the most promising one. For the regenerating system the treatment method could focus on either one. As for the single pass system peracetic acid could be added to reduce the amount of microorganism. To reduce the amount of organic matter an advanced oxidation process could be deployed with the advantage that it also could remove the microorganisms.

  10. Effect of growth conditions on microbial activity and iron-sulfide production by Desulfovibrio vulgaris

    International Nuclear Information System (INIS)

    Zhou, Chen; Vannela, Raveender; Hayes, Kim F.; Rittmann, Bruce E.

    2014-01-01

    Highlights: • Extended incubation time to 16 days allowed significant FeS crystallization. • A weakly acidic pH greatly enhanced particle growth of mackinawite. • Microbial metabolism of different donors systematically altered the ambient pH. • Greater sulfide accumulation stimulated mackinawite transformation to greigite. - Abstract: Sulfate-reducing bacteria (SRB) can produce iron sulfide (FeS) solids with mineralogical characteristics that may be beneficial for a variety of biogeochemical applications, such as long-term immobilization of uranium. In this study, the growth and metabolism of Desulfovibrio vulgaris, one of the best-studied SRB species, were comprehensively monitored in batch studies, and the biogenic FeS solids were characterized by X-ray diffraction. Controlling the pH by varying the initial pH, the iron-to-sulfate ratio, or the electron donor – affected the growth of D. vulgaris and strongly influenced the formation and growth of FeS solids. In particular, lower pH (from initial conditions or a decrease caused by less sulfate reduction, FeS precipitation, or using pyruvate as the electron donor) produced larger-sized mackinawite (Fe 1+x S). Greater accumulation of free sulfide, from more sulfate reduction by D. vulgaris, also led to larger-sized mackinawite and particularly stimulated mackinawite transformation to greigite (Fe 3 S 4 ) when the free sulfide concentration was 29.3 mM. Furthermore, sufficient free Fe 2+ led to the additional formation of vivianite [Fe 3 (PO 4 ) 2 ·8(H 2 O)]. Thus, microbially relevant conditions (initial pH, choice of electron donor, and excess or deficiency of sulfide) are tools to generate biogenic FeS solids of different characteristics

  11. Differences in microbial communities and performance between suspended and attached growth anaerobic membrane bioreactors treating synthetic municipal wastewater

    KAUST Repository

    Harb, Moustapha

    2015-08-14

    Two lab-scale anaerobic membrane bioreactors (AnMBRs), one up-flow attached-growth (UA) and another continuously stirred (CSTR), were operated under mesophilic conditions (35 °C) while treating synthetic municipal wastewater (800 mg L−1 COD). Each reactor was attached to both polyvinylidene fluoride (PVDF) and polyethersulfone (PES) microfiltration (MF) membranes in an external cross-flow configuration. Both reactors were started up and run under the same operating conditions for multiple steady-state experiments. Chemical oxygen demand (COD) removal rates were similar for both reactors (90–96%), but captured methane was found to be 11–18% higher for the CSTR than the UA reactor. Ion Torrent sequencing targeting 16S rRNA genes showed that several operational taxonomic units (OTUs) most closely related to fermentative bacteria (e.g., Microbacter margulisiae) were dominant in the suspended biomass of the CSTR, accounting for 30% of the microbial community. Conversely, methanogenic archaea (e.g., Methanosaeta) and syntrophic bacteria (e.g., Smithella propionica) were found in significantly higher relative abundances in the UA AnMBR as compared to the CSTR due to their affinity for surface attachment. Of the methanogens that were present in the CSTR sludge, hydrogenotrophic methanogens dominated (e.g., Methanobacterium). Measured EPS (both proteins and carbohydrates), which has been broadly linked to fouling, was determined to be consistently lower in the UA AnMBR membrane samples than in CSTR AnMBR membrane samples. Principal component analysis (PCA) based on HPLC profiles of soluble microbial products (SMPs) further demonstrated these differences between reactor types in replicate runs. The results of this study showed that reactor configuration can significantly impact the development of the microbial communities of AnMBRs that are responsible for both membrane and reactor performance.

  12. Macroeconomic Determinants of Economic Growth: A Review of International Literature

    Directory of Open Access Journals (Sweden)

    Chirwa Themba G.

    2016-12-01

    Full Text Available The paper conducts a qualitative narrative appraisal of the existing empirical literature on the key macroeconomic determinants of economic growth in developing and developed countries. Much as other empirical studies have investigated the determinants of economic growth using various econometric methods, the majority of these studies have not distinguished what drives or hinders economic growth in developing or developed countries. The study finds that the determinants of economic growth are different when this distinction is used. It reveals that in developing countries the key macroeconomic determinants of economic growth include foreign aid, foreign direct investment, fiscal policy, investment, trade, human capital development, demographics, monetary policy, natural resources, reforms and geographic, regional, political and financial factors. In developed countries, the study reveals that the key macroeconomic determinants that are associated with economic growth include physical capital, fiscal policy, human capital, trade, demographics, monetary policy and financial and technological factors.

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

    Directory of Open Access Journals (Sweden)

    H.S. El-Sheshtawy

    2015-06-01

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

  14. Analysis of the microbial growth in 60Co γ-irradiated foods by calorimetry

    International Nuclear Information System (INIS)

    Furuta, Masakazu; Hayashi, Toshio; Hamasaki, Koji; Wirkner, Sandra; Constantinoiu, Elena; Takahashi, Katsutada

    2002-01-01

    Using a heat conduction calorimeter equipped with 24 sample units the heat evolutions from growing 60 Co γ-irradiated bioburden of black pepper seeds and frozen beef were detected in the form of growth thermograms. 60 Co γ-irradiation affected the growth pattern in which a dose-dependent reduction of the growth rate constant was observed together with the retardation in growth, indicating a combination of bactericidal and bacteriostatic effects. We successfully determined the minimal inactivation doses for the two food samples using the relationship between the irradiation dose and the retardation in growth t α , or the growth rate constant μ obtained from the growth thermograms. These results strongly suggested the possibility of calorimetry as measure of predictive microbiology in food irradiation. (author)

  15. Analysis of the microbial growth in 60Co gamma-irradiated foods by calorimetry

    International Nuclear Information System (INIS)

    Furuta, M.; Hamasaki, K.; Wirkner, S.; Constantinoiu, E.; Takahashi, K.; Hayashi, T.

    2002-01-01

    Using a heat conduction calorimeter equipped with 24 sample units the heat evolutions from growing 60Co gamma-irradiated bioburden of black pepper seeds and frozen beef were detected in the form of growth thermograms. 60Co gamma-irradiation affected the growth pattern in which a dose-dependent reduction of the growth rate constant was observed together with the retardation in growth, indicating a combination of bactericidal and bacteriostatic effects. We successfully determined the minimal inactivation doses for the two food samples using the relationship between the irradiation dose and the retardation in growth talpha, or the growth rate constant mu obtained from the growth thermograms. These results strongly suggested the possibility of calorimetry as a measure of predictive microbiology in food irradiation

  16. Impact of metabolism and growth phase on the hydrogen isotopic composition of microbial fatty acids

    Science.gov (United States)

    Heinzelmann, Sandra M.; Villanueva, Laura; Sinke-Schoen, Danielle; Sinninghe Damsté, Jaap S.; Schouten, Stefan; van der Meer, Marcel T. J.

    2015-01-01

    Microorganisms are involved in all elemental cycles and therefore it is important to study their metabolism in the natural environment. A recent technique to investigate this is the hydrogen isotopic composition of microbial fatty acids, i.e., heterotrophic microorganisms produce fatty acids enriched in deuterium (D) while photoautotrophic and chemoautotrophic microorganisms produce fatty acids depleted in D compared to the water in the culture medium (growth water). However, the impact of factors other than metabolism have not been investigated. Here, we evaluate the impact of growth phase compared to metabolism on the hydrogen isotopic composition of fatty acids of different environmentally relevant microorganisms with heterotrophic, photoautotrophic and chemoautotrophic metabolisms. Fatty acids produced by heterotrophs are enriched in D compared to growth water with εlipid/water between 82 and 359‰ when grown on glucose or acetate, respectively. Photoautotrophs (εlipid/water between −149 and −264‰) and chemoautotrophs (εlipid/water between −217 and −275‰) produce fatty acids depleted in D. Fatty acids become, in general, enriched by between 4 and 46‰ with growth phase which is minor compared to the influence of metabolisms. Therefore, the D/H ratio of fatty acids is a promising tool to investigate community metabolisms in nature. PMID:26005437

  17. Effect of Microbial inoculation in combating the aluminium toxicity effect on growth of Zea mays.

    Science.gov (United States)

    Arora, P; Singh, G; Tiwari, A

    2017-07-31

    The present study is aimed at improving the aluminium tolerance in maize crop employing the potential of microbial inoculants in conferring resistance to these toxicities via production of certain chelating compounds like siderophores, exopolysachharides and organic acids. Acid soils have now-a-days become one of the key factors for limiting growth of many agriculturally important crops. Aluminium  is one of the major elements present in acid soils and is mainly responsible for toxicity in the soil. This aluminium is rapidly soluble in soil water and hence absorbed by plant roots under conditions where soil pH is below 5. This toxicity leads to severe root growth inhibition, thereby limiting the production of maize crops. It was observed that use of microbial inoculums can be helpful in elimination of these toxic compounds and prevent the inhibition of root growth . It was found that the soils contaminated with aluminium toxicity decreased the root length of maize plant significantly by 65% but Bacillus and Burkholderia inoculation increased this root length significantly by 1.4- folds and 2- folds respectively thereby combating the effect of aluminium toxicity. Aluminium concentration was found maximum in roots of plants which were grown under aluminium stress condition. But this aluminium accumulation decreased ̴ 2-folds when Burkholderia was used as seed inoculants under aluminium stress conditions. Also, at 60mM aluminium accumulation, phosphorus solubilisation in roots was found to be increased upto 30% on Burkholderia inoculation. However, Bacillus inoculation didn't show any significant difference in either of the case. Thus, the inoculation of seeds with Burkholderia isolates could prove to be a boon in sequestering aluminium toxicity in Zea mays.

  18. Inhibition of Microbial Growth by Fatty Amine Catalysts from Polyurethane Foam Test Tube Plugs

    Science.gov (United States)

    Bach, John A.; Wnuk, Richard J.; Martin, Delano G.

    1975-01-01

    When polyurethane foam test tube plugs are autoclaved, they release volatile fatty amines that inhibit the growth of some microorganisms. The chemical structures of these amines were determined by the use of a gas chromatographmass spectrometer. They are catalysts used to produce the foam. The problem of contaminating growth media with toxic substances released from polymeric materials is discussed. PMID:1096816

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

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2016-07-15

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

  20. Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture.

    Science.gov (United States)

    Grunert, Oliver; Reheul, Dirk; Van Labeke, Marie-Christine; Perneel, Maaike; Hernandez-Sanabria, Emma; Vlaeminck, Siegfried E; Boon, Nico

    2016-05-01

    Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated €15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  1. Elemental economy: microbial strategies for optimizing growth in the face of nutrient limitation.

    Science.gov (United States)

    Merchant, Sabeeha S; Helmann, John D

    2012-01-01

    Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility for fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near-universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental sparing and elemental recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels, including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes. Copyright © 2012

  2. Linking genes to microbial growth kinetics: an integrated biochemical systems engineering approach.

    Science.gov (United States)

    Koutinas, Michalis; Kiparissides, Alexandros; Silva-Rocha, Rafael; Lam, Ming-Chi; Martins Dos Santos, Vitor A P; de Lorenzo, Victor; Pistikopoulos, Efstratios N; Mantalaris, Athanasios

    2011-07-01

    The majority of models describing the kinetic properties of a microorganism for a given substrate are unstructured and empirical. They are formulated in this manner so that the complex mechanism of cell growth is simplified. Herein, a novel approach for modelling microbial growth kinetics is proposed, linking biomass growth and substrate consumption rates to the gene regulatory programmes that control these processes. A dynamic model of the TOL (pWW0) plasmid of Pseudomonas putida mt-2 has been developed, describing the molecular interactions that lead to the transcription of the upper and meta operons, known to produce the enzymes for the oxidative catabolism of m-xylene. The genetic circuit model was combined with a growth kinetic model decoupling biomass growth and substrate consumption rates, which are expressed as independent functions of the rate-limiting enzymes produced by the operons. Estimation of model parameters and validation of the model's predictive capability were successfully performed in batch cultures of mt-2 fed with different concentrations of m-xylene, as confirmed by relative mRNA concentration measurements of the promoters encoded in TOL. The growth formation and substrate utilisation patterns could not be accurately described by traditional Monod-type models for a wide range of conditions, demonstrating the critical importance of gene regulation for the development of advanced models closely predicting complex bioprocesses. In contrast, the proposed strategy, which utilises quantitative information pertaining to upstream molecular events that control the production of rate-limiting enzymes, predicts the catabolism of a substrate and biomass formation and could be of central importance for the design of optimal bioprocesses. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Rhizospheric microbial communities are driven by Panax ginseng at different growth stages and biocontrol bacteria alleviates replanting mortality

    Directory of Open Access Journals (Sweden)

    Linlin Dong

    2018-03-01

    Full Text Available The cultivation of Panax plants is hindered by replanting problems, which may be caused by plant-driven changes in the soil microbial community. Inoculation with microbial antagonists may efficiently alleviate replanting issues. Through high-throughput sequencing, this study revealed that bacterial diversity decreased, whereas fungal diversity increased, in the rhizosphere soils of adult ginseng plants at the root growth stage under different ages. Few microbial community, such as Luteolibacter, Cytophagaceae, Luteibacter, Sphingomonas, Sphingomonadaceae, and Zygomycota, were observed; the relative abundance of microorganisms, namely, Brevundimonas, Enterobacteriaceae, Pandoraea, Cantharellales, Dendryphion, Fusarium, and Chytridiomycota, increased in the soils of adult ginseng plants compared with those in the soils of 2-year-old seedlings. Bacillus subtilis 50-1, a microbial antagonist against the pathogenic Fusarium oxysporum, was isolated through a dual culture technique. These bacteria acted with a biocontrol efficacy of 67.8%. The ginseng death rate and Fusarium abundance decreased by 63.3% and 46.1%, respectively, after inoculation with B. subtilis 50-1. Data revealed that microecological degradation could result from ginseng-driven changes in rhizospheric microbial communities; these changes are associated with the different ages and developmental stages of ginseng plants. Biocontrol using microbial antagonists alleviated the replanting problem. KEY WORDS: Panax ginseng, Microbial communities, Replanting problem, High-throughput sequencing, Different ages, Bioremediation

  4. Microbial contamination determination of Cream suit,Traditional Ice Cream and Olovia in Yasuj City

    OpenAIRE

    SS Khoramrooz; M Sarikhani; SA Khosravani; M Farhang Falah; Y Mahmoudi; A Sharifi

    2015-01-01

    Background & aim: Prevalence of diseases caused by consumption of contaminated food has always been a problem all over the world, and every year spent on improving the disease is costly.Cream suit, Ice cream & olowye for ingredient substance and manufacture & preservation conditional have very high possibility for contamination.The aim of this study is Microbial contamination determination of Cream suit, Traditional Ice Cream and Olovia in Yasuj City Methods: This study is randomized cros...

  5. Crack growth determination on laboratory components

    International Nuclear Information System (INIS)

    Hurst, R.C.

    1993-01-01

    In order to aid design and support remanent life assessment of plant components operating at elevated temperatures, the reliability of the analytical methods, which translate materials data procured from the laboratory to the behaviour of actual components, requires validation. Such a validation can of course be interpreted from operating plant, however the potential risks involved encourage the development of out of plant techniques for the validation of representative components. For meaningful validation, these techniques need careful control and high accuracy which can best be achieved in a laboratory environment. As the laboratory component test should be designed to simulate actual plant conditions as closely as possible, the direct extension of the results to the plant component case requires scaling up. Consequently the successful development of such a test may even lead to the advantageous situation where it could form an alternative to the conventional route where, for example, it may not be possible to obtain the plant component's metallurgical structure in a conventional specimen or, alternatively, when too many assumptions are required in the analysis when translating to different geometries and stress systems. Under these conditions, in spite of the more sophisticated test requirements, it may prove more reasonable to opt for the more representative laboratory component data for use in design or lifetime prediction. The present work describes the application of the component validation test philosophy to the problem of crack growth under two rather different loading conditions. In both cases, crack growth is measured using the direct current potential drop (PD) technique on tubular metallic components containing artificial defects, however the plant conditions to be simulated lead to either creep or thermal fatigue. The creep studies on Alloy 800H support heat exchanger design for nuclear plant, solar towers and chemical plant, whereas the work on the

  6. Chemical diversity of microbial volatiles and their potential for plant growth and productivity

    Directory of Open Access Journals (Sweden)

    CHIDANANDA NAGAMANGALA KANCHISWAMY

    2015-03-01

    Full Text Available Microbial volatile organic compounds (MVOCs are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs and their potential physiological effects on crops and analyze potential and actual limitations for MVOC use as a sustainable strategy for improving productivity and reducing pesticide use.

  7. Optimal design of multistage chemostats in series using different microbial growth kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Muhammad [Petroleum Engineering Technology, Abu Dhabi Polytechnic (United Arab Emirates)

    2013-07-01

    In this paper, the optimum design of multistage chemostats (CSTRs) was investigated. The optimal design was based on the minimum overall reactor volume using different volume for each chemostat. The paper investigates three different microbial growth kinetics; Monod kinetics, Contois kinetics and the Logistic equation. The total dimensionless residence time (theta Total) was set as the optimization objective function that was minimized by varying the intermediate dimensionless substrate concentration (alfa i). The effect of inlet substrate concentration (S0) to the first reactor on the optimized total dimensionless residence time was investigated at a constant conversion of 0.90. In addition, the effect of conversion on the optimized total dimensionless residence time was also investigated at constant inlet substrate concentration (S0). For each case, optimization was done using up to five chemostats in series.

  8. Parameter estimations in predictive microbiology: Statistically sound modelling of the microbial growth rate.

    Science.gov (United States)

    Akkermans, Simen; Logist, Filip; Van Impe, Jan F

    2018-04-01

    When building models to describe the effect of environmental conditions on the microbial growth rate, parameter estimations can be performed either with a one-step method, i.e., directly on the cell density measurements, or in a two-step method, i.e., via the estimated growth rates. The two-step method is often preferred due to its simplicity. The current research demonstrates that the two-step method is, however, only valid if the correct data transformation is applied and a strict experimental protocol is followed for all experiments. Based on a simulation study and a mathematical derivation, it was demonstrated that the logarithm of the growth rate should be used as a variance stabilizing transformation. Moreover, the one-step method leads to a more accurate estimation of the model parameters and a better approximation of the confidence intervals on the estimated parameters. Therefore, the one-step method is preferred and the two-step method should be avoided. Copyright © 2017. Published by Elsevier Ltd.

  9. Biochar increases plant growth and alters microbial communities via regulating the moisture and temperature of green roof substrates.

    Science.gov (United States)

    Chen, Haoming; Ma, Jinyi; Wei, Jiaxing; Gong, Xin; Yu, Xichen; Guo, Hui; Zhao, Yanwen

    2018-09-01

    Green roofs have increasingly been designed and applied to relieve environmental problems, such as water loss, air pollution as well as heat island effect. Substrate and vegetation are important components of green roofs providing ecosystem services and benefiting the urban development. Biochar made from sewage sludge could be potentially used as the substrate amendment for green roofs, however, the effects of biochar on substrate quality and plant performance in green roofs are still unclear. We evaluated the effects of adding sludge biochar (0, 5, 10, 15 and 20%, v/v) to natural soil planted with three types of plant species (ryegrass, Sedum lineare and cucumber) on soil properties, plant growth and microbial communities in both green roof and ground ecosystems. Our results showed that sludge biochar addition significantly increased substrate moisture, adjusted substrate temperature, altered microbial community structure and increased plant growth. The application rate of 10-15% sludge biochar on the green roof exerted the most significant effects on both microbial and plant biomass by 63.9-89.6% and 54.0-54.2% respectively. Path analysis showed that biochar addition had a strong effect on microbial biomass via changing the soil air-filled porosity, soil moisture and temperature, and promoted plant growth through the positive effects on microbial biomass. These results suggest that the applications of biochar at an appropriate rate can significantly alter plant growth and microbial community structure, and increase the ecological benefits of green roofs via exerting effects on the moisture, temperature and nutrients of roof substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Determination of the feasibility of using open path FTIR to monitor levels of 3-methylfuran and 1-octen-3-ol for the purpose of detecting microbial contamination in indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Olive, Brent [Univ. of Alabama, Birmingham, AL (United States)

    1996-03-01

    Studies have shown that the presence of microbial growth correlates with health complaints associated with sick building syndrome. Microbial growth may be found in damp places within a building, and may be dispersed to other areas if present in the HVAC system. Certain individuals may be especially sensitive to the presence of these microorganisms, and may experience adverse reactions at extremely low concentrations. Unfortunately, the source of the problem may not be discovered because many times the microbial growth is not visible. However, there are some volatile organic compounds that are given off by certain microorganisms which may be used to determine the presence of microbial contamination. 3-Methylfuran is an excellent indicator of growing fungi. It is produced by a majority of fungi, and can be used as an indicator of ongoing growth. 1-Octen-3-ol is also produced by a number of fungi, and has been used in the past as an indicator of such. These two compounds and many other volatiles given off by microorganisms have been termed microbial volatile organic compounds (MVOCs). Many of these compounds are commonly found in indoor air, and thus, may be present even when there is not microbial contamination.

  11. Microbial stratification in low pH oxic and suboxic macroscopic growths along an acid mine drainage

    DEFF Research Database (Denmark)

    Méndez-García, Celia; Mesa, Victoria; Sprenger, Richard Remko

    2014-01-01

    Macroscopic growths at geographically separated acid mine drainages (AMDs) exhibit distinct populations. Yet, local heterogeneities are poorly understood. To gain novel mechanistic insights into this, we used OMICs tools to profile microbial populations coexisting in a single pyrite gallery AMD (pH...

  12. Trade-offs between microbial growth phases lead to frequency-dependent and non-transitive selection.

    Science.gov (United States)

    Manhart, Michael; Adkar, Bharat V; Shakhnovich, Eugene I

    2018-02-14

    Mutations in a microbial population can increase the frequency of a genotype not only by increasing its exponential growth rate, but also by decreasing its lag time or adjusting the yield (resource efficiency). The contribution of multiple life-history traits to selection is a critical question for evolutionary biology as we seek to predict the evolutionary fates of mutations. Here we use a model of microbial growth to show that there are two distinct components of selection corresponding to the growth and lag phases, while the yield modulates their relative importance. The model predicts rich population dynamics when there are trade-offs between phases: multiple strains can coexist or exhibit bistability due to frequency-dependent selection, and strains can engage in rock-paper-scissors interactions due to non-transitive selection. We characterize the environmental conditions and patterns of traits necessary to realize these phenomena, which we show to be readily accessible to experiments. Our results provide a theoretical framework for analysing high-throughput measurements of microbial growth traits, especially interpreting the pleiotropy and correlations between traits across mutants. This work also highlights the need for more comprehensive measurements of selection in simple microbial systems, where the concept of an ordinary fitness landscape breaks down. © 2018 The Author(s).

  13. Microbial stratification in low pH oxic and suboxic macroscopic growths along an acid mine drainage

    NARCIS (Netherlands)

    Méndez-Garcia, C.; Mesa, V.; Sprenger, R.R.; Richter, M.; Suarez Diez, M.; Solano, J.; Bargiela, R.; Golyshina, O.V.; Manteca, A.; Ramos, J.L.; Gallego, J.R.; Llorente, I.; Martins Dos Santos, V.A.P.; Jensen, O.N.; Paláez, A.I.; Sánchez, J.; Ferrer, M.

    2014-01-01

    Macroscopic growths at geographically separated acid mine drainages (AMDs) exhibit distinct populations. Yet, local heterogeneities are poorly understood. To gain novel mechanistic insights into this, we used OMICs tools to profile microbial populations coexisting in a single pyrite gallery AMD (pH

  14. Effect of microbial cell-free meat extract on the growth of spoilage bacteria.

    Science.gov (United States)

    Nychas, G-J E; Dourou, D; Skandamis, P; Koutsoumanis, K; Baranyi, J; Sofos, J

    2009-12-01

    This study examined the effect of microbial cell-free meat extract (CFME) derived from spoiled meat, in which quorum sensing (QS) compounds were present, on the growth kinetics (lag phase, and growth rate) of two spoilage bacteria, Pseudomonas fluorescens and Serratia marcescens. Aliquots of CFME from spoiled meat were transferred to Brain Heart Infusion broth inoculated with 10(3) CFU ml(-1) of 18 h cultures of Ps. fluorescens or Ser. marcescens, both fresh meat isolates; CFME derived from unspoiled fresh meat ('clean' meat) served as a control. Changes in impedance measurements were monitored for 48 h, and the detection time (Tdet) was recorded. It was found that in the absence of CFME containing QS compounds the Tdet was shorter (P meat. The rate of growth of Ps. fluorescens, recorded as the maximum slope rate of conductance changes (MSrCC), after Tdet, was higher (P meat. Similar results in MSrCC of impedance changes were obtained for Ser. marcescens. The study indicated that the growth rate (expressed in MSrCC units) of meat spoilage bacteria in vitro was enhanced in samples supplemented with CFME containing QS compounds compared to control samples (i.e., without CFME or with CFME from 'clean' meat). This behaviour may explain the dominant role of these two bacteria in the spoilage of meat. These results illustrate the potential effect of signalling compounds released during storage of meat on the behaviour of meat spoilage bacteria. Understanding such interactions may assist in the control of fresh meat quality and the extension of its shelf life.

  15. Growth, Age Determination and Longevity in the Giant African Snail ...

    African Journals Online (AJOL)

    Growth rates in terms of shell lengths were investigated in four subspecies of Archachatina marginata (Swainson) under culture conditions. Number of shell whorls, shell pigmentation and microsculpture were also studied to assess their usefulness in age determination. The snails displayed a sigmoid growth pattern, with ...

  16. Empirical evidence that soil carbon formation from plant inputs is positively related to microbial growth

    Science.gov (United States)

    Mark A. Bradford; Ashley D. Keiser; Christian A. Davies; Calley A. Mersmann; Michael S. Strickland

    2012-01-01

    Plant-carbon inputs to soils in the form of dissolved sugars, organic acids and amino acids fuel much of heterotrophic microbial activity belowground. Initial residence times of these compounds in the soil solution are on the order of hours, with microbial uptake a primary removal mechanism. Through microbial biosynthesis, the dissolved compounds become dominant...

  17. Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

    Energy Technology Data Exchange (ETDEWEB)

    Liu Feng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Tao Ran; Zhao Jianliang; Yang Jifeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhao Lanfeng [College of Resource and Environmental Science, South China Agricultural University, Guangzhou 510642 (China)

    2009-05-15

    The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

  18. Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

    International Nuclear Information System (INIS)

    Liu Feng; Ying Guangguo; Tao Ran; Zhao Jianliang; Yang Jifeng; Zhao Lanfeng

    2009-01-01

    The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

  19. Determinants of Economic Growth in Malaysia 1970-2010

    OpenAIRE

    Fauzi HUSSIN; Norazrul Mat ROS; Mohd Saifoul Zamzuri NOOR

    2013-01-01

    This paper investigates the determinants of economic growth in Malaysia. Trade openness, foreign direct investment, government development expenditure and gross fixed capital formation are used as indicators of economic growth. The study used time series data for the period 1970 to 2010. The Johansen and Juselius cointegration approach was applied to determine the long-run relationship between the variables. The study found that trade openness and foreign direct investment have significant bu...

  20. Determinants of Economic Growth: Empirical Evidence from Russian Regions

    Directory of Open Access Journals (Sweden)

    Svetlana Ledyaeva

    2008-06-01

    Full Text Available A modification of Barro and Sala-i-Martin empirical framework of growth model is specified to examine determinants of per capita growth in 74 Russian regions during period of 1996-2005. We utilize both panel and cross-sectional data. Results imply that in general regional growth in 1996-2005 is explained by the initial level of region's economic development, the 1998 financial crisis, domestic investments, and exports. Growth convergence between poor and rich regions in Russia was not found for the period studied.

  1. Dietary nisin modulates the gastrointestinal microbial ecology and enhances growth performance of the broiler chickens.

    Directory of Open Access Journals (Sweden)

    Damian Józefiak

    Full Text Available Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT. The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC diet was supplemented with salinomycin (60 mg/kg. The nisin (NI diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively of the bacteriocin. The negative control (NC diet contained no additives. At slaughter (35 days of age, activity of specific bacterial enzymes (α- and β-glucosidases, α-galactosidases and β-glucuronidase in crop, ileum and caeca were significantly higher (P<0.05 in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA and putrefactive SCFA (PSCFA in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001 decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI₉₀₀ and NI₂₇₀₀ groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary

  2. Microbial phylogeny determines transcriptional response of resistome to dynamic composting processes.

    Science.gov (United States)

    Wang, Cheng; Dong, Da; Strong, P J; Zhu, Weijing; Ma, Zhuang; Qin, Yong; Wu, Weixiang

    2017-08-16

    Animal manure is a reservoir of antibiotic resistance genes (ARGs) that pose a potential health risk globally, especially for resistance to the antibiotics commonly used in livestock production (such as tetracycline, sulfonamide, and fluoroquinolone). Currently, the effects of biological treatment (composting) on the transcriptional response of manure ARGs and their microbial hosts are not well characterized. Composting is a dynamic process that consists of four distinct phases that are distinguished by the temperature resulting from microbial activity, namely the mesophilic, thermophilic, cooling, and maturing phases. In this study, changes of resistome expression were determined and related to active microbiome profiles during the dynamic composting process. This was achieved by integrating metagenomic and time series metatranscriptomic data for the evolving microbial community during composting. Composting noticeably reduced the aggregated expression level of the manure resistome, which primarily consisted of genes encoding for tetracycline, vancomycin, fluoroquinolone, beta-lactam, and aminoglycoside resistance, as well as efflux pumps. Furthermore, a varied transcriptional response of resistome to composting at the ARG levels was highlighted. The expression of tetracycline resistance genes (tetM-tetW-tetO-tetS) decreased during composting, where distinctive shifts in the four phases of composting were related to variations in antibiotic concentration. Composting had no effect on the expression of sulfonamide and fluoroquinolone resistance genes, which increased slightly during the thermophilic phase and then decreased to initial levels. As indigenous populations switched greatly throughout the dynamic composting, the core resistome persisted and their reservoir hosts' composition was significantly correlated with dynamic active microbial phylogenetic structure. Hosts for sulfonamide and fuoroquinolone resistance genes changed notably in phylognetic structure

  3. [Microbial biomass and growth kinetics of microorganisms in chernozem soils under different farm land use modes].

    Science.gov (United States)

    Blagodatskiĭ, S A; Bogomolova, I N; Blagodatskaia, E V

    2008-01-01

    The carbon content of microbial biomass and the kinetic characteristics of microbial respiration response to substrate introduction have been estimated for chernozem soils of different farm lands: arable lands used for 10, 46, and 76 years, mowed fallow land, non-mowed fallow land, and woodland. Microbial biomass and the content of microbial carbon in humus (Cmic/Corg) decreased in the following order: soils under forest cenoses-mowed fallow land-10-year arable land-46- and 75-year arable land. The amount of microbial carbon in the long-plowed horizon was 40% of its content in the upper horizon of non-mowed fallow land. Arable soils were characterized by a lower metabolic diversity of microbial community and by the highest portion of microorganisms able to grow directly on glucose introduced into soil. The effects of different scenarios of carbon sequestration in soil on the reserves and activity of microbial biomass are discussed.

  4. [Influence of Mirabilis jalapa Linn. Growth on the Microbial Community and Petroleum Hydrocarbon Degradation in Petroleum Contaminated Saline-alkali Soil].

    Science.gov (United States)

    Jiao, Hai-hua; Cui, Bing-jian; Wu, Shang-hua; Bai, Zhi-hui; Huang, Zhan-bin

    2015-09-01

    In order to explore the effect of Mirabilis jalapa Linn. growth on the structure characteristics of the microbial community and the degradation of petroleum hydrocarbon (TPH) in the petroleum-contaminated saline-alkali soil, Microbial biomass and species in the rhizosphere soils of Mirabilis jalapa Linn. in the contaminated saline soil were studied with the technology of phospholipid fatty acids (PLFAs) analysis. The results showed that comparing to CK soils without Mirabilis jalapa Linn., the ratio of PLFAs species varied were 71. 4%, 69. 2% and 33. 3% in the spring, summer and autumn season, respectively. In addition, there was distinct difference of the biomasses of the microbial community between the CK and rhizosphere soils and among the difference seasons of growth of Mirabilis jalapa Linn.. Compare to CK soil, the degradation rates of total petroleum hydrocarbon (TPH) was increased by 47. 6%, 28. 3%, and 18. 9% in spring, summer, and autumn rhizosphere soils, respectively. Correlation analysis was used to determine the correlation between TPH degradation and the soil microbial community. 77. 8% of the total soil microbial PLFAs species showed positive correlation to the TPH degradation (the correlation coefficient r > 0), among which, 55. 6% of PLFAs species showed high positive correlation(the correlation coefficient was r≥0. 8). In addition, the relative content of SAT and MONO had high correlation with TPH degradation in the CK sample soils, the corelation coefficient were 0. 92 and 0. 60 respectively; However, the percent of positive correlation was 42. 1% in the rhizosphere soils with 21. 1% of them had high positive correlation. The relative content of TBSAT, MONO and CYCLO had moderate or low correlation in rhizosphere soils, and the correlation coefficient were 0. 56, 0. 50, and 0. 07 respectively. Our study showed that the growth of mirabilis Mirabilis jalapa Linn. had a higher influence on the species and biomass of microbial community in the

  5. Effects of 2-hydroxy-4-(methylthio) butanoic acid (HMB) on microbial growth in continuous culture.

    Science.gov (United States)

    Noftsger, S M; St-Pierre, N R; Karnati, S K R; Firkins, J L

    2003-08-01

    2-Hydroxy-4-(methylthio) butanoic acid (HMB) positively affects milk composition and yield, potentially through ruminal actions. Four continuous culture fermenters were used to determine the optimal concentration of HMB for digestibility of organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose and synthesis of microbial N. A highly degradable mix of hay and grain was used as a basal diet to simulate a typical lactation diet. Three concentrations of HMB (0, 0.055, and 0.110%) and one concentration of dl-Met (0.097%) were infused into the fermenters according to a 4 x 4 Latin square design. Digesta samples were collected during the last 3 d of each of the four 10-d experimental periods. Digestibility of OM, hemicellulose, and NDF was largely insensitive to treatment. Digestibility of ADF showed a quadratic effect to supplementation of HMB, with 0.055% having lower digestibility than 0 or 0.110%. Total production of VFA was not influenced by HMB supplementation, but differences in concentration and production of individual VFA were seen. Isobutyrate increased linearly with increasing HMB supplementation. Propionate concentration decreased linearly with increased HMB supplementation, but propionate production showed a quadratic trend (P = 0.13). A higher concentration of acetate was detected for dl-Met compared with the highest HMB concentration. There were trends (P HMB. Microbial efficiency was not different among treatments. The proportion of bacterial N produced from NH3-N decreased linearly with increasing HMB, and bacteria receiving dl-Met synthesized more N from NH3-N than those receiving HMB. These data suggest that supplementation of HMB may have a sparing effect on branched chain volatile fatty acids because the fatty acids are not needed to provide carbon for synthesis of valine, isoleucine and leucine with ammonia. Comparisons of bacterial community structure in the fermenter effluent samples using PCR amplicons

  6. Determinants of Economic Growth in V4 Countries and Romania

    Directory of Open Access Journals (Sweden)

    Simionescu Mihaela

    2017-03-01

    Full Text Available The middle and long-term slowdown in growth dynamics could bring serious social and political problems for V4 countries (Czech Republic, Slovak Republic, Hungary, Poland and Romania. It would threaten reaching benefits from potential of convergence process with the developed countries of the European Union. As a result, the V4 economies and Romania should find solutions to achieving a sustainable growth that is associated with an improvement of their international competitiveness. This paper provides an empirical analysis of factors that might determine a stable economic growth in the five mentioned countries. The empirical analysis conducted for the period of 2003-2016 employed Bayesian generalized ridge regression. The main results indicated that the FDI promoted economic growth in all countries, except the Slovak Republic. Only in the Czech Republic, the expenditure on education generated economic growth, while the expenditure on R&D had positive effects in Romania, Hungary and the Czech Republic.

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

    Science.gov (United States)

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

    2013-05-01

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

  8. By passing microbial resistance: xylitol controls microorganisms growth by means of its anti-adherence property.

    Science.gov (United States)

    Ferreira, Aline S; Silva-Paes-Leme, Annelisa F; Raposo, Nádia R B; da Silva, Sílvio S

    2015-01-01

    Xylitol is an important polyalcohol suitable for use in odontological, medical and pharmaceutical products and as an additive in food. The first studies on the efficacy of xylitol in the control and treatment of infections started in the late 1970s and it is still applied for this purpose, with safety and very little contribution to resistance. Xylitol seems to act against microorganisms exerting an anti-adherence effect. Some research studies have demonstrated its action against Gram-positive and Gram-negative bacteria and yeasts. However, a clear explanation of how xylitol is effective has not been completely established yet. Some evidence shows that xylitol acts on gene expression, down-regulating the ones which are involved in the microorganisms' virulence, such as capsule formation. Another possible clarification is that xylitol blocks lectin-like receptors. The most important aspect is that, over time, xylitol bypasses microbial resistance and succeeds in controlling infection, either alone or combined with another compound. In this review, the effect of xylitol in inhibiting the growth of a different microorganism is described, focusing on studies in which such an anti-adherent property was highlighted. This is the first mini-review to describe xylitol as an anti-adherent compound and take into consideration how it exerts such action.

  9. Microbial growth and quorum sensing antagonist activities of herbal plants extracts.

    Science.gov (United States)

    Al-Hussaini, Reema; Mahasneh, Adel M

    2009-09-03

    Antimicrobial and antiquorum sensing (AQS) activities of fourteen ethanolic extracts of different parts of eight plants were screened against four Gram-positive, five Gram-negative bacteria and four fungi. Depending on the plant part extract used and the test microorganism, variable activities were recorded at 3 mg per disc. Among the Grampositive bacteria tested, for example, activities of Laurus nobilis bark extract ranged between a 9.5 mm inhibition zone against Bacillus subtilis up to a 25 mm one against methicillin resistant Staphylococcus aureus. Staphylococcus aureus and Aspergillus fumigatus were the most susceptible among bacteria and fungi tested towards other plant parts. Of interest is the tangible antifungal activity of a Tecoma capensis flower extract, which is reported for the first time. However, minimum inhibitory concentrations (MIC's) for both bacteria and fungi were relatively high (0.5-3.0 mg). As for antiquorum sensing activity against Chromobacterium violaceum, superior activity (>17 mm QS inhibition) was associated with Sonchus oleraceus and Laurus nobilis extracts and weak to good activity (8-17 mm) was recorded for other plants. In conclusion, results indicate the potential of these plant extracts in treating microbial infections through cell growth inhibition or quorum sensing antagonism, which is reported for the first time, thus validating their medicinal use.

  10. Microbial Growth and Quorum Sensing Antagonist Activities of Herbal Plants Extracts

    Directory of Open Access Journals (Sweden)

    Reema Al-Hussaini

    2009-09-01

    Full Text Available Antimicrobial and antiquorum sensing (AQS activities of fourteen ethanolic extracts of different parts of eight plants were screened against four Gram-positive, five Gram-negative bacteria and four fungi. Depending on the plant part extract used and the test microorganism, variable activities were recorded at 3 mg per disc. Among the Grampositive bacteria tested, for example, activities of Laurus nobilis bark extract ranged between a 9.5 mm inhibition zone against Bacillus subtilis up to a 25 mm one against methicillin resistant Staphylococcus aureus. Staphylococcus aureus and Aspergillus fumigatus were the most susceptible among bacteria and fungi tested towards other plant parts. Of interest is the tangible antifungal activity of a Tecoma capensis flower extract, which is reported for the first time. However, minimum inhibitory concentrations (MIC's for both bacteria and fungi were relatively high (0.5-3.0 mg. As for antiquorum sensing activity against Chromobacterium violaceum, superior activity (>17 mm QS inhibition was associated with Sonchus oleraceus and Laurus nobilis extracts and weak to good activity (8-17 mm was recorded for other plants. In conclusion, results indicate the potential of these plant extracts in treating microbial infections through cell growth inhibition or quorum sensing antagonism, which is reported for the first time, thus validating their medicinal use.

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

    Science.gov (United States)

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

    2017-02-01

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

  12. [Determination of Azospirillum Brasilense Cells With Bacteriophages via Electrooptical Analysis of Microbial Suspensions].

    Science.gov (United States)

    Gulii, O I; Karavayeva, O A; Pavlii, S A; Sokolov, O I; Bunin, V D; Ignatov, O V

    2015-01-01

    The dependence-of changes in the electrooptical properties of Azospirillum brasilense cell suspension Sp7 during interaction with bacteriophage ΦAb-Sp7 on the number and time of interactions was studied. Incubation of cells with bacteriophage significantly changed the electrooptical signal within one minute. The selective effect of bacteriophage ΦAb on 18 strains of bacteria of the genus Azospirillum was studied: A. amazonense Ami4, A. brasilense Sp7, Cd, Sp107, Sp245, Jm6B2, Brl4, KR77, S17, S27, SR55, SR75, A. halopraeferans Au4, A. irakense KBC1, K A3, A. lipoferum Sp59b, SR65 and RG20a. We determined the limit of reliable determination of microbial cells infected with bacteriophage: - 10(4) cells/mL. The presence of foreign cell cultures of E. coli B-878 and E. coli XL-1 did not complicate the detection of A brasilense Sp7 cells with the use of bacteriophage ΦAb-Sp7. The results demonstrated that bacteriophage (ΦAb-Sp7 can be used for the detection of Azospirillum microbial cells via t electrooptical analysis of cell suspensions.

  13. Nation Building as a Determinent of Economic Growth

    Science.gov (United States)

    2010-05-18

    Consortium for Political and Social Reserch (2007). Mankiw , N. Gregory, David Romer, and David N. Weil. “A Contribution to the Empirics of Economic Growth...Determinent of Economic Growth 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6 . AUTHOR(S) 5d. PROJECT NUMBER Creasey. Ellyn Ann 5e. TASK NUMBER 51...J ss istance and econom ic aid impact the development process. The primary resu lts suggest a 1% increase in spending on nation building result s

  14. Joint determinants of fiscal policy, income inequality and economic growth

    OpenAIRE

    Leonel Muinelo-Gallo; Oriol Roca-Sagalés

    2012-01-01

    This paper analyses the relationship between income inequality and economic growth through fiscal policy. To this end, we present and estimate two systems of structural equiation with error components through which gross income inequality determines different fiscal policy outcomes, which subsequently affects the evolution of economic growth and net income inequality. The empirical results, obtained using an unbalanced panel data of 21 high-income OCDE countries during the period 1972-2006, s...

  15. Impact of metal pollution and Thlaspi caerulescens growth on soil microbial communities

    NARCIS (Netherlands)

    Epelde, L.; Becerril, J.M.; Kowalchuk, G.A.; Deng, Y.; Zhou, J.N.; Garbisu, C.

    2010-01-01

    Soil microorganisms drive critical functions in plant-soil systems. As such, various microbial properties have been proposed as indicators of soil functioning, making them potentially useful in evaluating the recovery of polluted soils via phytoremediation strategies. To evaluate microbial responses

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

    Directory of Open Access Journals (Sweden)

    Thanh Lam Phuoc

    2017-02-01

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

  17. Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

    Science.gov (United States)

    Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

    2018-06-15

    Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

  18. An Overview on Novel Microbial Determination Methods in Pharmaceutical and Food Quality Control

    Directory of Open Access Journals (Sweden)

    Mahboob Nemati

    2016-09-01

    Full Text Available Traditional microbiological methods tend to be labor-intensive and time-consuming. Rapid and novel methods in microbiological tests provide more sensitive, precise and reproducible results compared with conventional methods. In microbiology, the most rapid testing methods belong to the field of biotechnology such as PCR, ELISA, ATP bioluminescence and etc. Nevertheless impedance microbiology, biosensors and analytical procedures to determine microbial constituents are of significance. The present review article was conducted using internet databases and related scientific literatures and articles that provide information on developments in the rapid methods in microbiology. The main focus is on the application of rapid methods in microbial quality control of pharmaceutical products. Reviewed literature showed that rapid methods and automation in microbiology is an advanced area for studying and applying of improved methods in the early detection, and characterization of microorganisms and their products in food, pharmaceutical and cosmetic industrials as well as environmental monitoring and clinical applications. It can be concluded that rapid methods and automation in microbiology should continue as potent and efficient technologies to develop the novel tests to be performed in the future because of the ever-increasing concerns about the safety of food and pharmaceutical products. However the main issues to be considered are the scale up of developed methods and the regulatory requirements.

  19. Effects of degradable protein and non-fibre carbohydrates on microbial growth and fermentation in the rumen simulating fermenter (Rusitec

    Directory of Open Access Journals (Sweden)

    Xiang H. Zhao

    2015-05-01

    Full Text Available A rumen simulation technique (Rusitec apparatus with eight 800 ml fermentation vessels was used to investigate the effects of rumen degradable protein (RDP level and non-fibre carbohydrate (NFC type on ruminal fermentation, microbial growth, and populations of ruminal cellulolytic bacteria. Treatments consisted of two NFC types (starch and pectin supplemented with 0 g/d (low RDP or 1.56 g/d (high RDP sodium caseinate. Apparent disappearance of dry matter and organic matter was greater for pectin than for starch treatment (P<0.01 with low or high RDP. A NFC × RDP interaction was observed for neutral detergent fibre disappearance (P=0.01, which was lower for pectin than for starch only under low RDP conditions. Compared with starch, pectin treatment increased the copy numbers of Ruminococcus albus (P≤0.01 and Ruminococcus flavefaciens (P≤0.09, the molar proportion of acetate (P<0.01, the acetate:propionate ratio (P<0.01, and methane production (P<0.01, but reduced the propionate proportion (P<0.01. Increasing dietary RDP increased the production of total VFA (P=0.01, methane (P<0.01, ammonia N (P<0.01, and microbial N (P<0.01. Significant NFC × RDP interaction and interaction tendency were observed for ammonia N production (P=0.01 and daily N flow of total microorganisms (P=0.07, which did not differ under low RDP conditions, but pectin produced greater microbial N and less ammonia N than starch with increased RDP. Results showed NFC type, RDP level, and their interaction affected ruminal fermentation and microbial growth, and under sufficient ruminal degradable N pectin had greater advantage in microbial N synthesis than starch in vitro.

  20. Too big or too narrow? Disturbance characteristics determine the functional resilience in virtual microbial ecosystems

    Science.gov (United States)

    König, Sara; Firle, Anouk-Letizia; Koehnke, Merlin; Banitz, Thomas; Frank, Karin

    2017-04-01

    In general ecology, there is an ongoing debate about the influence of fragmentation on extinction thresholds. Whether this influence is positive or negative depends on the considered type of fragmentation: whereas habitat fragmentation often has a negative influence on population extinction thresholds, spatially fragmented disturbances are observed to have mostly positive effects on the extinction probability. Besides preventing population extinction, in soil systems ecology we are interested in analyzing how ecosystem functions are maintained despite disturbance events. Here, we analyzed the influence of disturbance size and fragmentation on the functional resilience of a microbial soil ecosystem. As soil is a highly heterogeneous environment exposed to disturbances of different spatial configurations, the identification of critical disturbance characteristics for maintaining its functions is crucial. We used the numerical simulation model eColony considering bacterial growth, degradation and dispersal for analyzing the dynamic response of biodegradation examplary for an important microbial ecosystem service to disturbance events of different spatial configurations. We systematically varied the size and the degree of fragmentation of the affected area (disturbance pattern). We found that the influence of the disturbance size on functional recovery and biodegradation performance highly depends on the spatial fragmentation of the disturbance. Generally, biodegradation performance decreases with increasing clumpedness and increasing size of the affected area. After spatially correlated disturbance events, biodegradation performance decreases linear with increasing disturbance size. After spatially fragmented disturbance events, on the other hand, an increase in disturbance size has no influence on the biodegradation performance until a critical disturbance size is reached. Is the affected area bigger than this critical size, the functional performance decreases

  1. Microbial growth yield estimates from thermodynamics and its importance for degradation of pesticides and formation of biogenic non-extractable residues

    DEFF Research Database (Denmark)

    Brock, Andreas Libonati; Kästner, M.; Trapp, Stefan

    2017-01-01

    NER. Formation of microbial mass can be estimated from the microbial growth yield, but experimental data is rare. Instead, we suggest using prediction methods for the theoretical yield based on thermodynamics. Recently, we presented the Microbial Turnover to Biomass (MTB) method that needs a minimum...... and using the released CO2 as a measure for microbial activity, we predicted a range for the formation of biogenic NER. For the majority of the pesticides, a considerable fraction of the NER was estimated to be biogenic. This novel approach provides a theoretical foundation applicable to the evaluation...

  2. Effect of diet and absence of protozoa on the rumen microbial community and on the representativeness of bacterial fractions used in the determination of microbial protein synthesis.

    Science.gov (United States)

    Belanche, A; de la Fuente, G; Pinloche, E; Newbold, C J; Balcells, J

    2012-11-01

    Accurate estimates of microbial synthesis in the rumen are vital to optimize ruminant nutrition. Liquid- (LAB) and solid-associated bacterial fractions (SAB) harvested from the rumen are generally considered as microbial references when microbial yield is calculated; however, factors that determine their composition are not completely understood. The aim of this study was to evaluate the effect of diet and absence or presence of rumen protozoa on the rumen microbial community. It was hypothesized that these treatments could modify the composition and representativeness of LAB and SAB. Twenty twin lambs (Ovis aries) were used; one-half of the twins were kept protozoa-free, and each respective twin sibling was faunated. At 6 mo of age, 5 animals from each group were randomly allocated to the experimental diets consisting of either alfalfa hay as the sole diet, or 50:50 mixed with ground barley grain. After 15 d of adaptation to the diet, animals were euthanized, rumen and abomasum contents were sampled, and LAB and SAB isolated. The presence of protozoa buffered the effect of diet on the rumen bacterial population. Faunated animals fed alfalfa hay had a greater abundance of F. succinogenes, anaerobic fungi and methanogens, as well as an enhanced rumen bacterial diversity. Cellulolytic bacteria were more abundant in SAB, whereas the abomasal abundance of most of the microorganisms studied was closer to those values observed in LAB. Rumen and abomasal samples showed similar bacterial DNA concentrations, but the fungal and protozoal DNA concentration in the abomasum was only 69% and 13% of that observed in the rumen, respectively, suggesting fungal and protozoal sequestration in the rumen or possible preferential degradation of fungal and protozoal DNA in the abomasum, or both. In conclusion, absence of protozoa and type of diet extensively modified the chemical composition of LAB and SAB as a consequence of changes in the microbial composition of these fractions.

  3. A novel process-based model of microbial growth: self-inhibition in Saccharomyces cerevisiae aerobic fed-batch cultures.

    Science.gov (United States)

    Mazzoleni, Stefano; Landi, Carmine; Cartenì, Fabrizio; de Alteriis, Elisabetta; Giannino, Francesco; Paciello, Lucia; Parascandola, Palma

    2015-07-30

    Microbial population dynamics in bioreactors depend on both nutrients availability and changes in the growth environment. Research is still ongoing on the optimization of bioreactor yields focusing on the increase of the maximum achievable cell density. A new process-based model is proposed to describe the aerobic growth of Saccharomyces cerevisiae cultured on glucose as carbon and energy source. The model considers the main metabolic routes of glucose assimilation (fermentation to ethanol and respiration) and the occurrence of inhibition due to the accumulation of both ethanol and other self-produced toxic compounds in the medium. Model simulations reproduced data from classic and new experiments of yeast growth in batch and fed-batch cultures. Model and experimental results showed that the growth decline observed in prolonged fed-batch cultures had to be ascribed to self-produced inhibitory compounds other than ethanol. The presented results clarify the dynamics of microbial growth under different feeding conditions and highlight the relevance of the negative feedback by self-produced inhibitory compounds on the maximum cell densities achieved in a bioreactor.

  4. Determining the nucleation rate from the dimer growth probability

    NARCIS (Netherlands)

    Ter Horst, J.H.; Kashchiev, D.

    2005-01-01

    A new method is proposed for the determination of the stationary one-component nucleation rate J with the help of data for the growth probability P2 of a dimer which is the smallest cluster of the nucleating phase. The method is based on an exact formula relating J and P2, and is readily applicable

  5. The utilization of microbial inoculants based on irradiated compost in dryland remediation to increase the growth of king grass and maize

    International Nuclear Information System (INIS)

    TRD Larasati; N Mulyana; D Sudradjat

    2016-01-01

    This research was conducted to evaluate the capability of functional microbial inoculants to remediate drylands. The microbial inoculants used consist of hydrocarbon-degrading microbial inoculants and plant-growth-promoting microbial inoculants. Compost-based carrier was sterilized by a gamma irradiation dose of 25 kGy to prepare seed inoculants. The irradiated-compost-based hydrocarbon-degrading microbial inoculants and king grass (Pennisetum purpureum Schumach.) were used to remediate oil-sludge-contaminated soil using in-situ composting for 60 days. The results showed that they could reduce THP (total petroleum hydrocarbons) by up to 82.23%. Plant-growth-promoting microbial inoculants were able to increase the dry weight of king grass from 47.39 to 100.66 g/plant, N uptake from 415.53 to 913.67 mg/plant, and P uptake from 76.52 to 178.33 mg/plant. Cow dung and irradiated-compost-based plant-growth-promoting microbial inoculants were able to increase the dry weight of maize (Zea mays L.) from 5.75 to 6.63 ton/ha (12.54%) and dry weight of grain potential from 5.30 to 7.15 ton/ha (35.03%). The results indicate that irradiated-compost-based microbial inoculants are suitable for remediating a dryland and therefore increase potential resources and improve the quality of the environment. (author)

  6. Fecal microbial determinants of fecal and systemic estrogens and estrogen metabolites: a cross-sectional study.

    Science.gov (United States)

    Flores, Roberto; Shi, Jianxin; Fuhrman, Barbara; Xu, Xia; Veenstra, Timothy D; Gail, Mitchell H; Gajer, Pawel; Ravel, Jacques; Goedert, James J

    2012-12-21

    High systemic estrogen levels contribute to breast cancer risk for postmenopausal women, whereas low levels contribute to osteoporosis risk. Except for obesity, determinants of non-ovarian systemic estrogen levels are undefined. We sought to identify members and functions of the intestinal microbial community associated with estrogen levels via enterohepatic recirculation. Fifty-one epidemiologists at the National Institutes of Health, including 25 men, 7 postmenopausal women, and 19 premenopausal women, provided urine and aliquots of feces, using methods proven to yield accurate and reproducible results. Estradiol, estrone, 13 estrogen metabolites (EM), and their sum (total estrogens) were quantified in urine and feces by liquid chromatography/tandem mass spectrometry. In feces, β-glucuronidase and β-glucosidase activities were determined by realtime kinetics, and microbiome diversity and taxonomy were estimated by pyrosequencing 16S rRNA amplicons. Pearson correlations were computed for each loge estrogen level, loge enzymatic activity level, and microbiome alpha diversity estimate. For the 55 taxa with mean relative abundance of at least 0.1%, ordinal levels were created [zero, low (below median of detected sequences), high] and compared to loge estrogens, β-glucuronidase and β-glucosidase enzymatic activity levels by linear regression. Significance was based on two-sided tests with α=0.05. In men and postmenopausal women, levels of total urinary estrogens (as well as most individual EM) were very strongly and directly associated with all measures of fecal microbiome richness and alpha diversity (R≥0.50, P≤0.003). These non-ovarian systemic estrogens also were strongly and significantly associated with fecal Clostridia taxa, including non-Clostridiales and three genera in the Ruminococcaceae family (R=0.57-0.70, P=0.03-0.002). Estrone, but not other EM, in urine correlated significantly with functional activity of fecal β-glucuronidase (R=0.36, P=0

  7. Mapping and determinism of soil microbial community distribution across an agricultural landscape.

    Science.gov (United States)

    Constancias, Florentin; Terrat, Sébastien; Saby, Nicolas P A; Horrigue, Walid; Villerd, Jean; Guillemin, Jean-Philippe; Biju-Duval, Luc; Nowak, Virginie; Dequiedt, Samuel; Ranjard, Lionel; Chemidlin Prévost-Bouré, Nicolas

    2015-06-01

    Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13 km². Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution of microbial biomass and diversity with patches of several hundreds of meters. Variance partitioning revealed that both microbial abundance and bacterial diversity distribution were highly dependent of soil properties and land use (total variance explained ranged between 55% and 78%). Microbial biomass and bacterial richness distributions were mainly explained by soil pH and texture whereas bacterial evenness distribution was mainly related to land management. Bacterial diversity (richness, evenness, and Shannon index) was positively influenced by cropping intensity and especially by soil tillage, resulting in spots of low microbial diversity in soils under forest management. Spatial descriptors also explained a small but significant portion of the microbial distribution suggesting that landscape configuration also shapes microbial biomass and bacterial diversity. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  8. Growth and development and their environmental and biological determinants.

    Science.gov (United States)

    da Rocha Neves, Kelly; de Souza Morais, Rosane Luzia; Teixeira, Romero Alves; Pinto, Priscilla Avelino Ferreira

    2016-01-01

    To investigate child growth, cognitive/language development, and their environmental and biological determinants. This was a cross-sectional, predictive correlation study with all 92 children aged 24-36 months who attended the municipal early childhood education network in a town in the Vale do Jequitinhonha region, in 2011. The socioeconomic profile was determined using the questionnaire of the Associação Brasileira de Empresas de Pesquisa. The socio-demographicand maternal and child health profiles were created through a self-prepared questionnaire. The height-for-age indicator was selected to represent growth. Cognitive/language development was assessed through the Bayley Scale of Infant and Toddler Development. The quality of educational environments was assessed by Infant/Toddler Environment Scale; the home environment was assessed by the Home Observation for Measurement of the Environment. The neighborhood quality was determined by a self-prepared questionnaire. A multivariate linear regression analysis was performed. Families were predominantly from socioeconomic class D, with low parental education. The prevalence of stunted growth was 14.1%; cognitive and language development were below average at 28.6% and 28.3%, respectively. Educational institutions were classified as inadequate, and 69.6% of homes were classified as presenting a risk for development. Factors such as access to parks and pharmacies and perceived security received the worst score regarding neighborhood environment. Biological variables showed a greater association with growth and environmental variables with development. The results showed a high prevalence of stunting and below-average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas environmental variables were associated with development

  9. Growth and development and their environmental and biological determinants

    Directory of Open Access Journals (Sweden)

    Kelly da Rocha Neves

    2016-06-01

    Full Text Available Abstract Objective To investigate child growth, cognitive/language development, and their environmental and biological determinants. Methods This was a cross-sectional, predictive correlation study with all 92 children aged 24-36 months who attended the municipal early childhood education network in a town in the Vale do Jequitinhonha region, in 2011. The socioeconomic profile was determined using the questionnaire of the Associação Brasileira de Empresas de Pesquisa. The socio-demographicand maternal and child health profiles were created through a self-prepared questionnaire. The height-for-age indicator was selected to represent growth. Cognitive/language development was assessed through the Bayley Scale of Infant and Toddler Development. The quality of educational environments was assessed by Infant/Toddler Environment Scale; the home environment was assessed by the Home Observation for Measurement of the Environment. The neighborhood quality was determined by a self-prepared questionnaire. A multivariate linear regression analysis was performed. Results Families were predominantly from socioeconomic class D, with low parental education. The prevalence of stunted growth was 14.1%; cognitive and language development were below average at 28.6% and 28.3%, respectively. Educational institutions were classified as inadequate, and 69.6% of homes were classified as presenting a risk for development. Factors such as access to parks and pharmacies and perceived security received the worst score regarding neighborhood environment. Biological variables showed a greater association with growth and environmental variables with development. Conclusion The results showed a high prevalence of stunting and below-average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas

  10. Impact of metal pollution and Thlaspi caerulescens growth on soil microbial communities.

    NARCIS (Netherlands)

    Epelde, L.; Becerril, J.M.; Kowalchuk, G.A.; Deng, Y.; Zhou, J.; Garbisu, C.

    2010-01-01

    been proposed as indicators of soil functioning, making them potentially useful in evaluating the recovery of polluted soils via phytoremediation strategies. To evaluate microbial responses to metal phytoextraction using hyperaccumulators, a microcosm experiment was carried out to study the impacts

  11. Effect of dry mycelium of Penicillium chrysogenum fertilizer on soil microbial community composition, enzyme activities and snap bean growth.

    Science.gov (United States)

    Wang, Bing; Liu, Huiling; Cai, Chen; Thabit, Mohamed; Wang, Pu; Li, Guomin; Duan, Ziheng

    2016-10-01

    The dry mycelium fertilizer (DMF) was produced from penicillin fermentation fungi mycelium (PFFM) following an acid-heating pretreatment to degrade the residual penicillin. In this study, it was applied into soil as fertilizer to investigate its effects on soil properties, phytotoxicity, microbial community composition, enzyme activities, and growth of snap bean in greenhouse. As the results show, pH, total nitrogen, total phosphorus, total potassium, and organic matter of soil with DMF treatments were generally higher than CON treatment. In addition, the applied DMF did not cause heavy metal and residual drug pollution of the modified soil. The lowest GI values (<0.3) were recorded at DMF8 (36 kg DMF/plat) on the first days after applying the fertilizer, indicating that severe phytotoxicity appeared in the DMF8-modified soil. Results of microbial population and enzyme activities illustrated that DMF was rapidly decomposed and the decomposition process significantly affected microbial growth and enzyme activities. The DMF-modified soil phytotoxicity decreased at the late fertilization time. DMF1 was considered as the optimum amount of DMF dose based on principal component analysis scores. Plant height and plant yield of snap bean were remarkably enhanced with the optimum DMF dose.

  12. Growth of Copper Production: Determinants and Empirical Evidence

    Directory of Open Access Journals (Sweden)

    Teodoro M. Santos

    2001-12-01

    Full Text Available From the 1950s to 1980, the copper mining industry exhibited a phenomenal growth rate. However, beginning in the early 1980s through 1997, growth rate turned negative without any sign of reversal. In order to restore the important role the industry used to play in the economy, policy makers, and decision makers must understand the factors responsible for the rapid growth from the 1950s until 1980 and the equally rapid decline during the 1980s and the 1990s.Growth of the copper mining industry is examined within the framework of a production function to identify the determinants of growth and their roles. The explanatory variables of growth are: copper resources, risk capital or investments, development in the world’s copper market, technology, human capital in mining, and domestic social, legal, and political environment. Except for copper resources, which has been supportive of positive growth, all the variables have components that supported the growth of the copper mining industry during the 1950s-1980s period and contributed to its decline thereafter.Availability of foreign capital, introduction of bulk mining technology, favorable copper prices and demand, and a conducive domestic social, political, and legal environment were responsible for the impressive growth experienced during the period from the 1950s to 1980. On the other hand, lack of foreign investment, declining market demand and prices, inadequate experience of local executives in the functions of top technical and managerial positions after 1974, arbitrary fiscal policies, lack of mining laws from 1986 to 1995, contradictory laws thereafter, and an uncertain domestic political, social, and legal environment caused the negative growth rates in the 1980s and 1990s. The 1995 Mining Code, which allows 100 percent foreign investments in mining under the financial and technical assistance mode of mineral disposition, could have revived the industry after 1995 were it allowed to

  13. Actual measurement, hygrothermal response experiment and growth prediction analysis of microbial contamination of central air conditioning system in Dalian, China.

    Science.gov (United States)

    Lv, Yang; Hu, Guangyao; Wang, Chunyang; Yuan, Wenjie; Wei, Shanshan; Gao, Jiaoqi; Wang, Boyuan; Song, Fangchao

    2017-04-03

    The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation.

  14. Determinants of Credit Growth: The Case of Montenegro

    Directory of Open Access Journals (Sweden)

    Ivanović Maja

    2016-05-01

    Full Text Available In the period before the crisis, Montenegro experienced a rapid credit growth, which coincided with the privatization of several banks and was followed by the entry of foreign banking groups, amplifying the banks’ lending process and increasing competition in this sector. This paper focuses on identification and estimation of determinants of credit growth in Montenegro, exploring both demand and supply side factors, and particularly paying attention to supply factors. Our findings confirm that positive economic developments and an increase in banks’ deposit potential lead to higher credit growth. Furthermore, our findings emphasize that the banking system soundness is decisive for promoting further bank’s lending activities. We provide evidence that the weakening of banks’ balance sheets, in terms of high non-performing loans and low solvency ratio, has a negative effect on credit supply.

  15. Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes.

    Science.gov (United States)

    Telling, Jon; Anesio, Alexandre M; Tranter, Martyn; Fountain, Andrew G; Nylen, Thomas; Hawkings, Jon; Singh, Virendra B; Kaur, Preeti; Musilova, Michaela; Wadham, Jemma L

    2014-01-01

    The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and subglacial regelation zones.

  16. Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes

    Directory of Open Access Journals (Sweden)

    Jon eTelling

    2014-12-01

    Full Text Available The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw towards fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and

  17. Fatores determinantes do crescimento infantil Determinant factors of infant growth

    Directory of Open Access Journals (Sweden)

    Sylvia de Azevedo Mello Romani

    2004-03-01

    Full Text Available Esta revisão enfoca os fatores que interferem no crescimento de crianças nos primeiros anos de vida. Foram utilizadas informações de artigos publicados em revistas científicas, teses e publicações de organizações internacionais. O crescimento infantil se constitui em um dos melhores indicadores de saúde da criança e o retardo estatural representa atualmente, a característica antropométrica mais representativa do quadro epidemiológico da desnutrição no Brasil. Ressaltando a importância do fator genético no crescimento, a revisão abrange com maior ênfase a atuação dos fatores extrínsecos, sabendo-se que o processo de crescimento resulta da interação entre a carga genética e os fatores do meio ambiente, os quais premitirão a maior ou menor expressão do potencial genético. Face a comprovada natureza multicausal do crescimento infantil, vários estudos têm sido desenvolvidos, buscando relacionar variáveis biológicas, socioeconômicas, maternas, ambientais, culturais, demográficas, nutricionais, entre outras, com a sua etiologia, seu desenvolvimento e sua manutenção. A revisão apresentada reforça o interesse em investigações sobre o crescimento na primeira infância que devem ser permanentes, devido, principalmente, às repercussões a longo prazo sobre a saúde infantil.This review focuses on factors interfering with growth during the first years of life. Information was collected from articles published in indexed scientific journals, theses, technical books and publications of international organizations. Infant growth is one of the best health indicators, and linear growth retardation is currently the most representative anthropometric characteristic of child nutrition epidemiology in Brazil. The review indicates the value of genetics in growth, focusing, however on the influence of the extrinsic factors. Growth process results from interaction between genetic and environmental factors, determining variation

  18. Microbial Inoculantes Effects on Growth Promotion of Mangrove and Citrullus vulgaris San Andrés Isla, Colombia

    Directory of Open Access Journals (Sweden)

    Tania Galindo

    2006-01-01

    Full Text Available In order to test the effect of two microbial inoculants (obtained from red and black mangrove roots on the growth and stability of mangrove and watermelon plants, four treatments were carried out in San Andres Island, Colombia. The treatments consisted in the application of the inoculants in: A. germinans propagules collected in a mangrove area, and then individually planted in gavels with sun-pasteurized soil (in order to decrease the microbial load, A. germinans and R. mangle plants collected in the proximity of nursery trees, A. germinans and R. mangle planted and maintained in nursery, and in Citrullus vulgaris seeds planted in a traditional cultivar without chemical fertilizers. The growth and vegetative development variables were: number of nodes, number of leaves and steam length. The inoculants (phosphate solubilizing microorganisms -PSM- and nitrogen fixing bacteria -NFB- were applied in the mentioned vegetable material, doing measures during three months. The results show a positive effect on growth measured by steam length in plants treated specifically with the inoculants in C. vulgaris and A. germinans seedlings maintained in nursery.

  19. Microbial growth and sensory quality of dried potato slices irradiated by electrons

    International Nuclear Information System (INIS)

    Kim, Hyun-Jin; Song, Hyeon-Jeong; Song, Kyung-Bin

    2011-01-01

    Electron beam irradiation was applied to secure the microbial safety of dried purple sweet potato. After purple sweet potato slices had been dehydrated with 20% (w/w) maltodextrin solution, the samples were irradiated at doses 2, 4, 6, 8, and 10 kGy and then stored at 20 o C for 60 days. Microbiological data indicated that the populations of total aerobic bacteria and of yeast and molds significantly decreased with increase in irradiation dosage. Specifically, microbial load was reduced by about three log cycles at 6 kGy compared to those of the control. Based on the color measurement of the potato slices, electron beam irradiation treatment did not affect the color quality. Sensory evaluation results also showed that electron beam irradiation did not affect overall sensory scores during storage. These results suggest that electron beam irradiation could be useful for improving microbial safety without impairing the quality of the potato slices during storage.

  20. Biopsychosocial determinants of pregnancy length and fetal growth.

    Science.gov (United States)

    St-Laurent, Jennifer; De Wals, Philippe; Moutquin, Jean-Marie; Niyonsenga, Theophile; Noiseux, Manon; Czernis, Loretta

    2008-05-01

    The causes and mechanisms related to preterm delivery and intrauterine growth restriction are poorly understood. Our objective was to assess the direct and indirect effects of psychosocial and biomedical factors on the duration of pregnancy and fetal growth. A self-administered questionnaire was distributed to pregnant women attending prenatal ultrasound clinics in nine hospitals in the Montérégie region in the province of Quebec, Canada, from November 1997 to May 1998. Prenatal questionnaires were linked with birth certificates. Theoretical models explaining pregnancy length and fetal growth were developed and tested, using path analysis. In order to reduce the number of variables from the questionnaire, a principal component analysis was performed, and the three most important new dimensions were retained as explanatory variables in the final models. Data were available for 1602 singleton pregnancies. The biophysical score, covering both maternal age and the pre-pregnancy body mass index, was the only variable statistically associated with pregnancy length. Smoking, obstetric history, maternal health and biophysical indices were direct predictors of fetal growth. Perceived stress, social support and self-esteem were not directly related to pregnancy outcomes, but were determinants of smoking and the above-mentioned biomedical variables. More studies are needed to identify the mechanisms by which adverse psychosocial factors are translated into adverse biological effects.

  1. Child nutritional status and child growth in Kenya: socioeconomic determinants.

    Science.gov (United States)

    Deolalikar, A B

    1996-01-01

    The determinants of weight and height are explored using nationally representative data for Kenya. The author also uses recall data on child birth weights to estimate conditional reduced-form demand relations for weight gain among 7907 children aged 0-5 years. Maternal education was found to be a significant determinant of weight, height, and weight gain, with secondary schooling having larger, but not significantly different effects than primary schooling. Per capita household expenditure is highly significant but with only small numerical effects. Birth weight has a large, negative effect upon subsequent weight gain, indicating almost complete catch-up growth by age one. The effect becomes more negative when birth weight is treated as an endogenous variable. There is no evidence of any catch-up growth beyond age three. The study results indicate that small deficits in birth weight are not likely to be permanent, with infants making up for birth weight deficits completely within the first year of life through biological catch-up growth.

  2. An Apple Fruit Fermentation (AFF) Treatment Improves the Composition of the Rhizosphere Microbial Community and Growth of Strawberry (Fragaria × ananassa Duch ‘Benihoppe’) Seedlings

    Science.gov (United States)

    Bu, Yufen; Shao, Wei; Huang, Weijing; Ji, Qianlong; Yao, Yuncong

    2016-01-01

    Plant growth can be promoted by the application of apple fruit fermentation (AFF), despite unclear of the underlying mechanisms, the effects involved in AFF on rhizosphere microorganisms have been hypothesized. We investigated the consequences of applying AFF alone or in combination with Bacillus licheniformis to strawberry tissue culture seedlings in vitro, the analyses of Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rDNA were performed to determine AFF effects on rhizosphere. Moreover, the growth index and antioxidant enzyme activities were determined 30 days after treatments. We identified five dominant bacteria in AFF: Coprinus atramentarius, Bacillus megaterium, Bacillus licheniformis, Weissella and B. subtilis. The greatest number of bacterial species were observed in the rhizosphere of control matrix (water treated), and the lowest diversity appeared in the rhizosphere soil treated with 108 cfu/mL B. licheniformis alone. Combining AFF plus B. licheniformis in one treatment resulted in the largest leaf area, plant height, root length, plant weight, and the markedly higher activities of antioxidant enzymes. We conclude that a combination of AFF plus B. licheniformis treatment to matrix can increase antioxidant enzymes activities in strawberry seedlings, optimize the status of rhizosphere microbial, and promote plant growth. PMID:27755580

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

    Science.gov (United States)

    Sanchez, Alvaro; Gore, Jeff

    2013-01-01

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

  4. 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

  5. Metagenomic profiling of microbial composition and antibiotic resistance determinants in Puget Sound.

    Science.gov (United States)

    Port, Jesse A; Wallace, James C; Griffith, William C; Faustman, Elaine M

    2012-01-01

    Human-health relevant impacts on marine ecosystems are increasing on both spatial and temporal scales. Traditional indicators for environmental health monitoring and microbial risk assessment have relied primarily on single species analyses and have provided only limited spatial and temporal information. More high-throughput, broad-scale approaches to evaluate these impacts are therefore needed to provide a platform for informing public health. This study uses shotgun metagenomics to survey the taxonomic composition and antibiotic resistance determinant content of surface water bacterial communities in the Puget Sound estuary. Metagenomic DNA was collected at six sites in Puget Sound in addition to one wastewater treatment plant (WWTP) that discharges into the Sound and pyrosequenced. A total of ~550 Mbp (1.4 million reads) were obtained, 22 Mbp of which could be assembled into contigs. While the taxonomic and resistance determinant profiles across the open Sound samples were similar, unique signatures were identified when comparing these profiles across the open Sound, a nearshore marina and WWTP effluent. The open Sound was dominated by α-Proteobacteria (in particular Rhodobacterales sp.), γ-Proteobacteria and Bacteroidetes while the marina and effluent had increased abundances of Actinobacteria, β-Proteobacteria and Firmicutes. There was a significant increase in the antibiotic resistance gene signal from the open Sound to marina to WWTP effluent, suggestive of a potential link to human impacts. Mobile genetic elements associated with environmental and pathogenic bacteria were also differentially abundant across the samples. This study is the first comparative metagenomic survey of Puget Sound and provides baseline data for further assessments of community composition and antibiotic resistance determinants in the environment using next generation sequencing technologies. In addition, these genomic signals of potential human impact can be used to guide initial

  6. Metagenomic profiling of microbial composition and antibiotic resistance determinants in Puget Sound.

    Directory of Open Access Journals (Sweden)

    Jesse A Port

    Full Text Available Human-health relevant impacts on marine ecosystems are increasing on both spatial and temporal scales. Traditional indicators for environmental health monitoring and microbial risk assessment have relied primarily on single species analyses and have provided only limited spatial and temporal information. More high-throughput, broad-scale approaches to evaluate these impacts are therefore needed to provide a platform for informing public health. This study uses shotgun metagenomics to survey the taxonomic composition and antibiotic resistance determinant content of surface water bacterial communities in the Puget Sound estuary. Metagenomic DNA was collected at six sites in Puget Sound in addition to one wastewater treatment plant (WWTP that discharges into the Sound and pyrosequenced. A total of ~550 Mbp (1.4 million reads were obtained, 22 Mbp of which could be assembled into contigs. While the taxonomic and resistance determinant profiles across the open Sound samples were similar, unique signatures were identified when comparing these profiles across the open Sound, a nearshore marina and WWTP effluent. The open Sound was dominated by α-Proteobacteria (in particular Rhodobacterales sp., γ-Proteobacteria and Bacteroidetes while the marina and effluent had increased abundances of Actinobacteria, β-Proteobacteria and Firmicutes. There was a significant increase in the antibiotic resistance gene signal from the open Sound to marina to WWTP effluent, suggestive of a potential link to human impacts. Mobile genetic elements associated with environmental and pathogenic bacteria were also differentially abundant across the samples. This study is the first comparative metagenomic survey of Puget Sound and provides baseline data for further assessments of community composition and antibiotic resistance determinants in the environment using next generation sequencing technologies. In addition, these genomic signals of potential human impact can be used

  7. Optimization of marine waste based-growth media for microbial lipase production using mixture design methodology.

    Science.gov (United States)

    Sellami, Mohamed; Kedachi, Samiha; Frikha, Fakher; Miled, Nabil; Ben Rebah, Faouzi

    2013-01-01

    Lipase production by Staphylococcus xylosus and Rhizopus oryzae was investigated using a culture medium based on a mixture of synthetic medium and supernatants generated from tuna by-products and Ulva rigida biomass. The proportion of the three medium components was optimized using the simplex-centroid mixture design method (SCMD). Results indicated that the experimental data were in good agreement with predicted values, indicating that SCMD was a reliable method for determining the optimum mixture proportion of the growth medium. Maximal lipase activities of 12.5 and 23.5 IU/mL were obtained with a 50:50 (v:v) mixture of synthetic medium and tuna by-product supernatant for Staphylococcus xylosus and Rhizopus oryzae, respectively. The predicted responses from these mixture proportions were also validated experimentally.

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

    Science.gov (United States)

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

    2009-11-01

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

  9. Limits determination of microbial contamination present on surfaces from a pharmaceutical microbiology district reference laboratory

    Directory of Open Access Journals (Sweden)

    Natalia Charry

    2016-06-01

    Full Text Available Context: The bioburden present on the pharmaceutical microbiology laboratory’s surfaces, may increase the risk of cross-contamination when analytical tests are being carried out; periodic monitoring allows to set limits that reduce the risk. Aims: To determinate the limits of bioburden present on seven surfaces of the pharmaceutical microbiology laboratory, after the cleaning and disinfection process. Methods: The swabbing method was used for sampling. With a 25 cm2 stencil and a sterile swab, a sample was taken, passing the swab over five points of every surface chosen. A total aerobic microbial count and a total yeast and mold count was done. Finally, the average and the standard deviation of the counts was obtained. Results: The average from the counts obtained on each surface selected for the study, were below the recommended limits by international entities like the World Health Organization and the European Union, between others; also, the results generated in this study, allow to classify the biosafety cabinet as an ISO 5 area and the other areas as ISO 7. Conclusions: Bioburden levels on the tested surfaces are considered low, reducing the risk of cross-contamination, which could have a negative impact on laboratory’s activities. Also, it follows that disinfectant concentration used, is effectively.

  10. Soil biochemical properties and microbial resilience in agroforestry systems: effects on wheat growth under controlled drought and flooding conditions.

    Science.gov (United States)

    Rivest, David; Lorente, Miren; Olivier, Alain; Messier, Christian

    2013-10-01

    Agroforestry is increasingly viewed as an effective means of maintaining or even increasing crop and tree productivity under climate change while promoting other ecosystem functions and services. This study focused on soil biochemical properties and resilience following disturbance within agroforestry and conventional agricultural systems and aimed to determine whether soil differences in terms of these biochemical properties and resilience would subsequently affect crop productivity under extreme soil water conditions. Two research sites that had been established on agricultural land were selected for this study. The first site included an 18-year-old windbreak, while the second site consisted in an 8-year-old tree-based intercropping system. In each site, soil samples were used for the determination of soil nutrient availability, microbial dynamics and microbial resilience to different wetting-drying perturbations and for a greenhouse pot experiment with wheat. Drying and flooding were selected as water stress treatments and compared to a control. These treatments were initiated at the beginning of the wheat anthesis period and maintained over 10 days. Trees contributed to increase soil nutrient pools, as evidenced by the higher extractable-P (both sites), and the higher total N and mineralizable N (tree-based intercropping site) found in the agroforestry compared to the conventional agricultural system. Metabolic quotient (qCO2) was lower in the agroforestry than in the conventional agricultural system, suggesting higher microbial substrate use efficiency in agroforestry systems. Microbial resilience was higher in the agroforestry soils compared to soils from the conventional agricultural system (windbreak site only). At the windbreak site, wheat growing in soils from agroforestry system exhibited higher aboveground biomass and number of grains per spike than in conventional agricultural system soils in the three water stress treatments. At the tree

  11. The effect of starch, inulin, and degradable protein on ruminal fermentation and microbial growth in rumen simulation technique

    Directory of Open Access Journals (Sweden)

    Xiang H. Zhao

    2014-03-01

    Full Text Available A rumen simulation technique apparatus with eight 800 mL fermentation vessels was used to investigate the effects of rumen degradable protein (RDP level and non-fibre carbohydrate (NFC type on ruminal fermentation, microbial growth, and populations of ruminal cellulolytic bacteria. Treatments consisted of two NFC types (starch and inulin supplemented with 0 g/d (low RDP or 1.56 g/d (high RDP sodium caseinate. No significant differences existed among dietary treatments in the apparent disappearance of dietary nutrients except for dietary N, which increased with increased dietary RDP (P<0.001. Compared with starch, inulin treatments reduced the molar proportion of acetate (P<0.001, the acetate:propionate ratio (P<0.001, and methane production (P=0.006, but increased the butyrate proportion (P<0.001. Increased dietary RDP led to increases in production of total volatile fatty acid (P=0.014 and methane (P=0.050, various measures of N (P≤0.046, and 16s rDNA copy numbers of Ruminococcus flavefaciens (P≤0.010. Non-fibre carbohydrate source did not affect daily microbial N flow regardless of dietary RDP, but ammonia N production was lower for inulin than for starch treatments under high RDP conditions (P<0.001. Compared with starch treatments, inulin depressed the copy numbers of Fibrobacter succinogenes in solid fraction (P=0.023 and R. flavefaciens in liquid (P=0.017 and solid fractions (P=0.007, but it increased the carboxymethylcellulase activity in solid fraction (P=0.045. Current results suggest that starch and inulin differ in ruminal volatile fatty acid fermentation but have similar effects on ruminal digestion and microbial synthesis in vitro, although inulin suppressed the growth of partial ruminal cellulolytic bacteria.

  12. The effect of microbial inocula on the growth of black locust, Siberian elm and silver maple seedlings

    Directory of Open Access Journals (Sweden)

    Hajnal-Jafari Timea

    2014-01-01

    Full Text Available Growth and development of forest plants depend mostly on the soil microbial activity since no mineral or organic fertilizers are applied. Microbial processes can be activated and conditions for plants development improved with the introduction of selected microorganisms in the soil. With the aim of obtaining quality planting material in a shorter period of time, the effects of Azotobacter chroococcum and Streptomyces sp. on the early growth of black locust (Robinia pseudoacacia, Siberian elm (Ulmus pumila and silver-leaf maple (Acer dasycarpum were investigated in this study. Microorganisms were applied individually and in a mixture (1:1. Plant height was measured on the 90th, 120th and 180th day after planting. Plant diameter, as well as the number of actinomycetes and azotobacters was measured at the end of the vegetation period (180 days after planting. Applied microorganisms had a positive effect on the seedling height in all three plant species, with the best effect found in the black locust. Effectiveness of applied microorganisms on seedling diameter was the highest in the silver-leaf maple. The largest number of azotobacters was found in the rhizosphere of black locust. Number of microorganisms from both groups was increased in the inoculated variants. [Projekat Ministarstva nauke Republike Srbije, br. III 43002

  13. Determination and comparison of microbial loads in atmospheres of two hospitals in Izmir, Turkey.

    Science.gov (United States)

    Aydin Çakir, Nergüze; Uçar, Füsun Bahriye; Haliki Uztan, Alev; Corbaci, Cengiz; Akpinar, Onur

    2013-01-01

    Nosocomial infections, also known as hospital-acquired infections, has become one of the most important health problems in health care units worldwide. The presented study aims to determine the average amount of microorganism loads and to show that the atmospheres of the two hospitals can be a potential source regarding nosocomial infections. The effect of surface and floor disinfection processes in the two hospitals and the antibiotic susceptibility of the bacterial isolates were also evaluated. Microorganisms were isolated from air samples collected from different areas (patient wards, corridors, operating theatres and postoperative units) of the two hospitals in Izmir. Sampling was conducted between December 2006 - March 2007. During the 3-month sampling period, the average number of live microorganisms in the air samples collected from second-class environments in the hospital 1 and the hospital 2 was found to be 224.44 and 536.66 cfu/m(3) , respectively. The average number of microorganisms in hospital 2 collected before the disinfection process was higher than those after the disinfection process. However, because of the closure of the air-conditioning system and the hepa filters after the disinfection process, this was reversed in hospital 1. In total, 54 and 42 isolates were obtained from hospital 1 and hospital 2, respectively. 49 isolates from hospital 1 and 35 isolates from hospital 2 were identified as Staphylacoccus sp. The remaining isolates were identified as Aerococcus sp. and Enterococcus sp. Pseudomonas sp. was not determined in the air samples of the two hospitals. It was detected that the microbial loads in the atmospheres of the two hospitals studied varied greatly depending on the number of people in the environment. As the results indicate, the total number of microorganisms in the atmospheres of operating theatres in both hospitals does not pose a threat according to the Air Microbe Index.

  14. Dietary marker effects on fecal microbial ecology, fecal VFA, nutrient digestibility coefficients, and growth performance in finishing pigs.

    Science.gov (United States)

    Kerr, B J; Weber, T E; Ziemer, C J

    2015-05-01

    control diet. In Exp. 2, no effect of dietary marker on pig performance was noted. Overall, the data indicate that the inclusion of Cr2O3, Fe2O3, or TiO2 as digestibility markers have little to no impact on microbial ecology, fecal ammonia or VFA concentrations, nutrient digestibility, or pig growth performance indicating they are suitable for use in digestion studies.

  15. Capacity of Albit® Plant Growth Stimulator for Mitigating Side-effects of Pesticides on Soil Microbial Respiration

    Directory of Open Access Journals (Sweden)

    Natalia N. Karpun

    2017-11-01

    Full Text Available Microorganisms give an early and integrated measure of soil functioning. In particular, soil microbial respiration is recommended for monitoring soil quality. The present study aims to determine the capacity of Albit® (poly-β-hydroxybutyrate, PHB to reduce the detrimental effects of pesticides on soil microbial respiration. The effects of three conventional pesticides (deltamethrin, dithianon, and difenoconazole on basal respiration (BR and substrate-induced respiration (SIR were assessed in the presence and absence of Albit®. The studied pesticides caused negative impacts on soil functioning, reducing BR and SIR. Applications of Albit® increased BR and SIR, and both BR and SIR were kept similar to the control when pesticides were applied with Albit®. PHB, an active ingredient of Albit®, is known to increase beneficial microflora in the rhizosphere due to its regulatory activity on indigenous microorganisms. Thus, more studies should be carried out under different edaphoclimatic conditions to study the benefits of Albit® applications along with pesticides in order to mitigate their side effects on soil microbial functioning.

  16. Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.

    Science.gov (United States)

    Basta, David W; Bergkessel, Megan; Newman, Dianne K

    2017-11-28

    Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest. IMPORTANCE Growth-arrested bacteria are ubiquitous in nature and disease yet understudied at the molecular level. For example, growth-arrested cells constitute a major subpopulation of mature biofilms, serving as an antibiotic-tolerant reservoir in chronic

  17. Microbial modeling of Alicyclobacillus acidoterrestris CRA 7152 growth in orange juice with nisin added.

    Science.gov (United States)

    Peña, Wilmer Edgard Luera; de Massaguer, Pilar Rodriguez

    2006-08-01

    The adaptation time of Alicyclobacillus acidoterrestris CRA 7152 in orange juice was determined as a response to pH (3 to 5.8), temperature (20 to 54 degrees C), soluble solids concentration ((o)Brix; 11 to 19 (o)Brix), and nisin concentration (0 to 70 IU/ ml) effects. A four-factor central composite rotational design was used. Viable microorganisms were enumerated by plating on K medium (pH 3.7). Two primary models were used to represent growth and adaptation time. A second-order polynomial model was applied to analyze the effects of factors. Results showed that the Baranyi and Roberts model was better than the modified Gompertz model, considering the determination coefficient (R2) for experimental data description. Inhibition of bacteria can be obtained through several studied combinations for at least 47 days of storage. The shortest period of adaptation was observed between 37 to 45 degrees C, with pHs between 4 and 5, yet the longest periods of adaptation could be obtained around 20 degrees C with pHs close to 3.0. Statistical analysis of the quadratic model showed that the adaptation time increased as temperature or pH decreased, and as nisin concentration or soluble solids increased. The model showed that adaptation time has a minimum value for juice without nisin added, with 13.5% soluble solids, pH 5.0, and incubated at 43.8 degrees C. The statistical parameters that validated this model were an R2 of 0.816, a bias factor of 0.96, and an accuracy factor of 1.14. Manipulation of more than one factor, as well as the use of an antimicrobial agent, can be an alternative to preventing the development of A. acidoterrestris in orange juice, thus contributing to increased orange juice shelf life.

  18. Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Fred Brokman; John Selker; Mark Rockhold

    2004-01-26

    While numerous techniques exist for remediation of contaminant plumes in groundwater or near the soil surface, remediation methods in the deep vadose zone are less established due to complex transport dynamics and sparse microbial populations. There is a lack of knowledge on how physical and hydrologic features of the vadose zone control microbial growth and colonization in response to nutrient delivery during bioremediation. Yet pollution in the vadose zone poses a serious threat to the groundwater resources lying deeper in the sediment. While the contaminants may be slowly degraded by native microbial communities, microbial degradation rates rarely keep pace with the spread of the pollutant. It is crucial to increase indigenous microbial degradation in the vadose zone to combat groundwater contamination.

  19. Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Brockman, Fred J.; Selker, John S.; Rockhold, Mark L.

    2004-10-31

    Executive Summary - While numerous techniques exist for remediation of contaminant plumes in groundwater or near the soil surface, remediation methods in the deep vadose zone are less established due to complex transport dynamics and sparse microbial populations. There is a lack of knowledge on how physical and hydrologic features of the vadose zone control microbial growth and colonization in response to nutrient delivery during bioremediation. Yet pollution in the vadose zone poses a serious threat to the groundwater resources lying deeper in the sediment. While the contaminants may be slowly degraded by native microbial communities, microbial degradation rates rarely keep pace with the spread of the pollutant. It is crucial to increase indigenous microbial degradation in the vadose zone to combat groundwater contamination...

  20. Economic growth and its determinants in countries in transitio

    Directory of Open Access Journals (Sweden)

    Kestrim Avdimetaj

    2015-11-01

    Full Text Available Main purpose of this scientific research is to analyze the countries in transition; in particular, through this research we will explain the economic growth and its determinants in the countries in transition. Referring to the fact that many ex-communist countries were faced with a transition from a socialist economic system into the economic system of free market, and this phase of transformation is also known as transition, we will analyze this phase in details. The materials contained in this research are based on data taken directly from Financial Institutions, European Central Bank, as well as many other relevant prestigious institutions of countries in transition. The first section of this research begins with the introduction, presenting broadly the economic growth in countries in transition and the manner of their transformation, as well as the identification of hypothesis contained in this research. The second section contains the review of the literature, where we have cited parts from many authors who conducted studies in this broadly and productive field. In the third section are explained the mathematical formulas, that specify the econometric model, as well as the method of assessment, i.e. multiple regression analysis. Then, through the calculations of STATA, we will substitute the values of variables obtained in formula and test them through the selected model. In the last section we will interpret the outcomes derived from calculations in the program, supporting or dismissing hypothesis presented in this scientific research. This scientific research is limited, because many other important variables impacting the economic growth, such as instruments of monetary and fiscal policy, economic freedom, etc., have not been incorporated.

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

    Science.gov (United States)

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

    2017-09-01

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

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

    OpenAIRE

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

    2013-01-01

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

  3. Metabolism of dinosaurs as determined from their growth

    Science.gov (United States)

    Lee, Scott A.

    2015-09-01

    A model based on cellular properties is used to analyze the mass growth curves of 20 dinosaurs. This analysis yields the first measurement of the average cellular metabolism of dinosaurs. The organismal metabolism is also determined. The cellular metabolism of dinosaurs is found to decrease with mass at a slower rate than is observed in extant animals. The organismal metabolism increases with the mass of the dinosaur. These results come from both the Saurischia and Ornithischia branches of Dinosauria, suggesting that the observed metabolic features were common to all dinosaurs. The results from dinosaurs are compared to data from extant placental and marsupial mammals, a monotreme, and altricial and precocial birds, reptiles, and fish. Dinosaurs had cellular and organismal metabolisms in the range observed in extant mesotherms.

  4. Metabolism of dinosaurs as determined from their growth.

    Science.gov (United States)

    Lee, Scott A

    2015-09-01

    A model based on cellular properties is used to analyze the mass growth curves of 20 dinosaurs. This analysis yields the first measurement of the average cellular metabolism of dinosaurs. The organismal metabolism is also determined. The cellular metabolism of dinosaurs is found to decrease with mass at a slower rate than is observed in extant animals. The organismal metabolism increases with the mass of the dinosaur. These results come from both the Saurischia and Ornithischia branches of Dinosauria, suggesting that the observed metabolic features were common to all dinosaurs. The results from dinosaurs are compared to data from extant placental and marsupial mammals, a monotreme, and altricial and precocial birds, reptiles, and fish. Dinosaurs had cellular and organismal metabolisms in the range observed in extant mesotherms.

  5. Influence of Inoculation, Nitrogen and Phosphorus Levels on Wheat Growth and Soil Microbial Biomass-N Using 15N Techniques

    International Nuclear Information System (INIS)

    Galal, Y.G.; El-Ghandour, I.A.; Abdel Raouf, A.M.; Osman, M.E.

    2003-01-01

    Pot experiment was carried out with wheat that cultivated in virgin sandy soil and inoculated with Rhizobium (Rh), mycorrhizea (VAM) and mixture of both. The objective of this work was to verify the potential of these inoculum on wheat production, nutrient acquisition and microbial biomass N (MBN) contribution as affected by N and P fertilizers levels. MBN was detected through the fumigation-extraction method. Nitrogen and phosphorus fertilizers were applied at three levels, 0; 25 ppm N and 3.3 ppm P and 50 ppm N and 6.6 ppm P in the form of ( 15 NH 4 ) 2 SO 4 , 5% atom excess and super-phosphate, respectively. The effect of inoculation and chemical fertilizers on dry matter (DM), N and P uptake (shoot and grain) and MBN were traced. The obtained data revealed that the highest DM and N uptake by wheat shoot were recorded with the dual inoculation (Rh + VAM) at the highest level of N and P fertilizers. The highest grain yield was detected with single inoculum of AM fungi while N and P uptake were with dual inoculation at the same rate of fertilizers. Inoculation with Rh either alone or in combination with VAM have a positive and stimulative effect on wheat growth and N and P uptake indicating the possibilities of extending the use of symbiotic microorganisms to be applied with cereals. The fluctuation in the soil microbial biomass N did not gave a chance to recognize, exactly, the impact of inoculation and/or fertilization levels

  6. Effects of forage:concentrate ratio and forage type on apparent digestibility, ruminal fermentation, and microbial growth in goats.

    Science.gov (United States)

    Cantalapiedra-Hijar, G; Yáñez-Ruiz, D R; Martín-García, A I; Molina-Alcaide, E

    2009-02-01

    The effects of forage type and forage:concentrate ratio (F:C) on apparent nutrient digestibility, ruminal fermentation, and microbial growth were investigated in goats. A comparison between liquid (LAB) and solid (SAB)-associated bacteria to estimate microbial N flow (MNF) from urinary purine derivative excretion was also examined. Treatments were a 2 x 2 factorial arrangement of forage type (grass hay vs. alfalfa hay) and high vs. low F:C (70:30 and 30:70, respectively). Four ruminally cannulated goats were fed, at maintenance intake, 4 experimental diets according to a 4 x 4 Latin square design. High-concentrate diets resulted in greater (P 0.05) when diets included alfalfa hay. Total protozoa numbers and holotricha proportion were greater and less (P forage used. The MNF measured in goats fed different diets was influenced by the bacterial pellet (LAB or SAB). In addition, the purine bases:N ratio values found were different from those reported in the literature, which underlines the need for these variables to be analyzed directly in pellets isolated from specific animals and experimental conditions.

  7. Metabolic enzyme cost explains variable trade-offs between microbial growth rate and yield.

    Directory of Open Access Journals (Sweden)

    Meike T Wortel

    2018-02-01

    Full Text Available Microbes may maximize the number of daughter cells per time or per amount of nutrients consumed. These two strategies correspond, respectively, to the use of enzyme-efficient or substrate-efficient metabolic pathways. In reality, fast growth is often associated with wasteful, yield-inefficient metabolism, and a general thermodynamic trade-off between growth rate and biomass yield has been proposed to explain this. We studied growth rate/yield trade-offs by using a novel modeling framework, Enzyme-Flux Cost Minimization (EFCM and by assuming that the growth rate depends directly on the enzyme investment per rate of biomass production. In a comprehensive mathematical model of core metabolism in E. coli, we screened all elementary flux modes leading to cell synthesis, characterized them by the growth rates and yields they provide, and studied the shape of the resulting rate/yield Pareto front. By varying the model parameters, we found that the rate/yield trade-off is not universal, but depends on metabolic kinetics and environmental conditions. A prominent trade-off emerges under oxygen-limited growth, where yield-inefficient pathways support a 2-to-3 times higher growth rate than yield-efficient pathways. EFCM can be widely used to predict optimal metabolic states and growth rates under varying nutrient levels, perturbations of enzyme parameters, and single or multiple gene knockouts.

  8. The effect of dosages of microbial consortia formulation and synthetic fertilizer on the growth and yield of field-grown chili

    Science.gov (United States)

    Istifadah, N.; Sapta, D.; Krestini, H.; Natalie, B.; Suryatmana, P.; Nurbaity, A.; Hidersah, R.

    2018-03-01

    Chili (Capsicum annuum, L) is one of important horticultural crop in Indonesia. Formulation of microbial consortia containing Bacillus subtilis, Pseudomonas sp., Azotobacter chroococcum and Trichoderma harzianum has been developed. This study evaluated the effects of dosage of the microbial formulation combined with NPK fertilizer on growth and yield of chili plants in the field experiment. The experiment was arranged in completely randomized design of factorial, in which the first factor was dosage of formulation (0, 2.5, 5.0, 7.5, 10 g per plant) and the second factor was NPK fertilizer dosage (0, 25, 50 and 75% of the standard dosage). The treatments were replicated three times. For application, the formulation was mixed with chicken manure 1:10 (w/v). The results showed that application of microbial formulation solely improved the chili growth. There was interaction between dosages of the microbial formulation and NPK fertilizer in improving plant height, nitrogen availability and the chili yield, while there was no interaction between those dosages in improving the root length. Combination between microbial formulation at the dosage of 5.0-7.5 g per plant combined with NPK fertilizer with the dosage 50 or 75% of the standard dosage support relatively better growth and the chili yield.

  9. INITIAL MICROBIAL ADHESION IS A DETERMINANT FOR THE STRENGTH OF BIOFILM ADHESION

    NARCIS (Netherlands)

    BUSSCHER, HJ; VANDERMEI, HC; Bos, R.R.M.

    1995-01-01

    This paper presents a hypothesis on the importance of initial microbial adhesion in the overall process of biofilm formation. The hypothesis is based on the realization that dynamic shear conditions exist in many environments, such as in the oral cavity, or on rocks and ship hulls. Recognizing that

  10. Effects of various weaning times on growth performance, rumen fermentation and microbial population of yellow cattle calves

    Directory of Open Access Journals (Sweden)

    Huiling Mao

    2017-11-01

    Full Text Available Objective This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3 or to early weaned (EW group where calves were weaned when the feed intake of solid feed (starter reached 500 g (EW500, n = 5, 750 g (EW750, n = 5, or 1,000 g (EW1,000, n = 5. Results Compared with NW, the EW treatments increased average daily gain (p0.05, but changes in bacterial composition were found. Conclusion From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results.

  11. Effects of Resveratrol and Essential Oils on Growth Performance, Immunity, Digestibility and Fecal Microbial Shedding in Challenged Piglets

    Directory of Open Access Journals (Sweden)

    S. T. Ahmed

    2013-05-01

    Full Text Available A study was conducted to evaluate the effects of resveratrol and essential oils from medicinal plants on the growth performance, immunity, digestibility, and fecal microbial shedding of weaned piglets. A total of 48 weaned piglets (8 kg initial weight, 28-d-old were randomly allotted to four dietary treatments with 3 replications of 4 piglets each. The dietary treatments were NC (negative control; basal diet, PC (positive control; basal diet+0.002% apramycin, T1 (basal diet+0.2% resveratrol, and T2 (basal diet+0.0125% essential oil blend. All piglets were orally challenged with 5 ml culture fluid containing 2.3×108 cfu/ml of Escherichia coli KCTC 2571 and 5.9×108 cfu/ml Salmonella enterica serover Typhimurium. The PC group (p0.05. Serum IgG level was increased in the T1 group, whereas TNF-α levels was reduced in the supplemented groups compared to control (p<0.05. The PC diet improved the dry matter (DM digestibility, whereas PC and T2 diets improved nitrogen (N digestibility compared to NC and T1 diets (p<0.05. Fecal Salmonella and E. coli counts were reduced in all treatment groups compared to control (p<0.05. Fecal Lactobacillus spp. count was increased in the T2 group compared to others (p<0.05. Dietary treatments had no significant effect on fecal Bacillus spp. count throughout the entire experimental period. Based on these results, resveratrol showed strong potential as antibiotic alternatives for reversing the adverse effects of weaning stress on growth performance, immunity and microbial environment in E. coli and Salmonella-challenged piglets.

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

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Kumari, Bollipo Dyana Ranjitha

    2013-08-01

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

  13. PLANT-MICROBIAL INTERACTIONS IN THE RHIZOSPHERE – STRATEGIES FOR PLANT GROWTH-PROMOTION

    Directory of Open Access Journals (Sweden)

    Marius Stefan

    2012-03-01

    Full Text Available Plant growth-promoting rhizobacteria (PGPR are a group of bacteria that can actively colonize plant rootsand enhance plant growth using different mechanisms: production of plant growth regulators like indoleacetic acid,gibberellic acid, cytokinins and ethylene(Zahir et al., 2003, providing the host plant with fixed nitrogen, solubilizationof soil phosphorus, enhance Fe uptake, biocontrol, reducing the concentration of heavy metals. PGPR are perfectcandidates to be used as biofertilizers – eco-friendly alternative to common applied chemical fertilizer in today’sagriculture. The most important benefit of PGPR usage is related to the reduction of environmental pollution in conditionof increasing crop yield. This review presents the main mechanisms involved in PGPR promotion of plant growth.

  14. Better to light a candle than curse the darkness: illuminating spatial localization and temporal dynamics of rapid microbial growth in the rhizosphere

    Directory of Open Access Journals (Sweden)

    Patrick M Herron

    2013-09-01

    Full Text Available The rhizosphere is a hotbed of microbial activity in ecosystems, fueled by carbon compounds from plant roots. Basic questions about the location and dynamics of plant-spurred microbial growth in the rhizosphere are difficult to answer with standard, destructive soil assays mixing a multitude of microbe-scale microenvironments in a single, often sieved, sample. Soil microbial biosensors designed with the luxCDABE reporter genes fused to a promoter of interest enable continuous imaging of the microbial perception of (and response to environmental conditions in soil. We used the common soil bacterium Pseudomonas putida KT2440 as host to plasmid pZKH2 containing a fusion between the strong constituitive promoter nptII and luxCDABE (coding for light-emitting proteins from Vibrio fischeri. Experiments in liquid media demonstrated that high light production by KT2440/pZKH2 was associated with rapid microbial growth supported by high carbon availability. We applied the biosensors in microcosms filled with non-sterile soil in which corn (Zea mays L., black poplar (Populus nigra L. or tomato (Solanum lycopersicum L. was growing. We detected minimal light production from microbiosensors in the bulk soil, but biosensors reported continuously from around roots for as long as six days. For corn, peaks of luminescence were detected 1-4 and 20-35 mm along the root axis behind growing root tips, with the location of maximum light production moving farther back from the tip as root growth rate increased. For poplar, luminescence around mature roots increased and decreased on a coordinated diel rhythm, but was not bright near root tips. For tomato, luminescence was dynamic, but did not exhibit a diel rhythm, appearing in acropetal waves along roots. KT2440/pZKH2 revealed that root tips are not always the only, or even the dominant, hotspots for rhizosphere microbial growth, and carbon availability is highly variable in space and time around roots.

  15. Determinants of Inclusive Growth in Africa: Role of Health and ...

    African Journals Online (AJOL)

    This paper examines the role of health and population growth on inclusive growth in selected 14 African countries from 1995 to 2012. Using the Fixed effect method, the findings indicate that finances from the health sector have greater impact towards the inclusiveness of growth in Africa. It indicated that adequate financing ...

  16. Determination of Growth Rate and Age Structure of Boswellia ...

    African Journals Online (AJOL)

    Bheema

    Department of Land Resource Management and Environmental Protection, ... seasonality in climate, in many tropical areas there is seasonality in rainfall which ... seasonal growth of trees thereby produce annual growth rings (Fichtler et al., 2003). ... ring boundaries, concentric growth rings around the entire cross-section of ...

  17. Biofilm growth on polyvinylchloride surface incubated in suboptimal microbial warm water and effect of sanitizers on biofilm removal post biofilm formation

    Science.gov (United States)

    An in vitro experiment was conducted to understand the nature of biofilm growth on polyvinyl chloride (PVC) surface when exposed to sub optimal quality microbial water (> 4 log10 cfu/ml) obtained from poultry drinking water source mimicking water in waterlines during the first week of poultry broodi...

  18. Effect of gamma irradiation and storage time on microbial growth and physicochemical characteristics of pumpkin (Cucurbita Moschata Duchesne ex Poiret) puree.

    Science.gov (United States)

    Gliemmo, María F; Latorre, María E; Narvaiz, Patricia; Campos, Carmen A; Gerschenson, Lía N

    2014-01-01

    The effect of gamma irradiation (0-2 kGy) and storage time (0-28 days) on microbial growth and physicochemical characteristics of a packed pumpkin puree was studied. For that purpose, a factorial design was applied. The puree contained potassium sorbate, glucose and vanillin was stored at 25°C . Gamma irradiation diminished and storage time increased microbial growth. A synergistic effect between both variables on microbial growth was observed. Storage time decreased pH and color of purees. Sorbate content decreased with storage time and gamma irradiation. Mathematical models of microbial growth generated by the factorial design allowed estimating that a puree absorbing 1.63 kGy would have a shelf-life of 4 days. In order to improve this time, some changes in the applied hurdles were assayed. These included a thermal treatment before irradiation, a reduction of irradiation dose to 0.75 kGy and a decrease in storage temperature at 20°C . As a result, the shelf-life of purees increased to 28 days.

  19. Foliar application of microbial and plant based biostimulants increases growth and potassium uptake in almond (Prunus dulcis [Mill.] D. A. Webb).

    Science.gov (United States)

    Saa, Sebastian; Olivos-Del Rio, Andres; Castro, Sebastian; Brown, Patrick H

    2015-01-01

    The use of biostimulants has become a common practice in agriculture. However, there is little peer-reviewed research on this topic. In this study we tested, under controlled and replicated conditions, the effect of one biostimulant derived from seaweed extraction (Bio-1) and another biostimulant derived from microbial fermentation (Bio-2). This experiment utilized 2-years-old almond plants over two growing seasons in a randomized complete design with a full 2 × 4 factorial structure with two soil potassium treatments (125 μg g(-1) of K vs. 5 μg g(-1)) and four foliar treatments (No spray, Foliar-K, Bio-1, Bio-2). Rubidium was utilized as a surrogate for short-term potassium uptake and plant growth, nutrient concentration, and final plant biomass were evaluated. There was a substantial positive effect of both biostimulant treatments on total shoot leaf area, and significant increases in shoot length and biomass under adequate soil potassium supply with a positive effect of Bio-1 only under low K supply. Rubidium uptake was increased by Bio-1 application an effect that was greater under the low soil K treatment. Though significant beneficial effects of the biostimulants used on plant growth were observed, it is not possible to determine the mode of action of these materials. The results presented here illustrate the promise and complexity of research involving biostimulants.

  20. Foliar application of microbial and plant based biostimulants increases growth and potassium uptake in almond (Prunus dulcis [Mill.] D. A. Webb

    Directory of Open Access Journals (Sweden)

    Sebastian eSaa

    2015-02-01

    Full Text Available The use of biostimulants has become a common practice in agriculture. However, there is little peer-reviewed research on this topic. In this study we tested, under controlled and replicated conditions, the effect of one biostimulant derived from seaweed extraction (Bio-1 and another biostimulant derived from microbial fermentation (Bio-2. This experiment utilized two-year-old almond plants over two growing seasons in a randomized complete design with a full 2 x 4 factorial structure with two soil potassium treatments (125 µg g-1 of K vs 5 µg g-1 and four foliar treatments (No spray, Foliar-K, Bio-1, Bio-2. Rubidium was utilized as a surrogate for short-term potassium uptake and plant growth, nutrient concentration, and final plant biomass were evaluated. There was a substantial positive effect of both biostimulant treatments on total shoot leaf area, and significant increases in shoot length and biomass under adequate soil potassium supply with a positive effect of Bio-1 only under low K supply. Rubidium uptake was increased by Bio-1 application an effect that was greater under the low soil K treatment. Though significant beneficial effects of the biostimulants used on plant growth were observed, it is not possible to determine the mode of action of these materials. The results presented here illustrate the promise and complexity of research involving biostimulants.

  1. Microbial phylogeny determines transcriptional response of resistome to dynamic composting processes

    OpenAIRE

    Wang, Cheng; Dong, Da; Strong, P. J.; Zhu, Weijing; Ma, Zhuang; Qin, Yong; Wu, Weixiang

    2017-01-01

    Background Animal manure is a reservoir of antibiotic resistance genes (ARGs) that pose a potential health risk globally, especially for resistance to the antibiotics commonly used in livestock production (such as tetracycline, sulfonamide, and fluoroquinolone). Currently, the effects of biological treatment (composting) on the transcriptional response of manure ARGs and their microbial hosts are not well characterized. Composting is a dynamic process that consists of four distinct phases tha...

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

    Science.gov (United States)

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

    2009-04-01

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

  3. Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments.

    Science.gov (United States)

    Mayor, Daniel J; Gray, Nia B; Elver-Evans, Joanna; Midwood, Andrew J; Thornton, Barry

    2013-01-01

    Copper is essential for healthy cellular functioning, but this heavy metal quickly becomes toxic when supply exceeds demand. Marine sediments receive widespread and increasing levels of copper contamination from antifouling paints owing to the 2008 global ban of organotin-based products. The toxicity of copper will increase in the coming years as seawater pH decreases and temperature increases. We used a factorial mesocosm experiment to investigate how increasing sediment copper concentrations and the presence of a cosmopolitan bioturbating amphipod, Corophium volutator, affected a range of ecosystem functions in a soft sediment microbial community. The effects of copper on benthic nutrient release, bacterial biomass, microbial community structure and the isotopic composition of individual microbial membrane [phospholipid] fatty acids (PLFAs) all differed in the presence of C. volutator. Our data consistently demonstrate that copper contamination of global waterways will have pervasive effects on the metabolic functioning of benthic communities that cannot be predicted from copper concentrations alone; impacts will depend upon the resident macrofauna and their capacity for bioturbation. This finding poses a major challenge for those attempting to manage the impacts of copper contamination on ecosystem services, e.g. carbon and nutrient cycling, across different habitats. Our work also highlights the paucity of information on the processes that result in isotopic fractionation in natural marine microbial communities. We conclude that the assimilative capacity of benthic microbes will become progressively impaired as copper concentrations increase. These effects will, to an extent, be mitigated by the presence of bioturbating animals and possibly other processes that increase the influx of oxygenated seawater into the sediments. Our findings support the move towards an ecosystem approach for environmental management.

  4. Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments.

    Directory of Open Access Journals (Sweden)

    Daniel J Mayor

    Full Text Available Copper is essential for healthy cellular functioning, but this heavy metal quickly becomes toxic when supply exceeds demand. Marine sediments receive widespread and increasing levels of copper contamination from antifouling paints owing to the 2008 global ban of organotin-based products. The toxicity of copper will increase in the coming years as seawater pH decreases and temperature increases. We used a factorial mesocosm experiment to investigate how increasing sediment copper concentrations and the presence of a cosmopolitan bioturbating amphipod, Corophium volutator, affected a range of ecosystem functions in a soft sediment microbial community. The effects of copper on benthic nutrient release, bacterial biomass, microbial community structure and the isotopic composition of individual microbial membrane [phospholipid] fatty acids (PLFAs all differed in the presence of C. volutator. Our data consistently demonstrate that copper contamination of global waterways will have pervasive effects on the metabolic functioning of benthic communities that cannot be predicted from copper concentrations alone; impacts will depend upon the resident macrofauna and their capacity for bioturbation. This finding poses a major challenge for those attempting to manage the impacts of copper contamination on ecosystem services, e.g. carbon and nutrient cycling, across different habitats. Our work also highlights the paucity of information on the processes that result in isotopic fractionation in natural marine microbial communities. We conclude that the assimilative capacity of benthic microbes will become progressively impaired as copper concentrations increase. These effects will, to an extent, be mitigated by the presence of bioturbating animals and possibly other processes that increase the influx of oxygenated seawater into the sediments. Our findings support the move towards an ecosystem approach for environmental management.

  5. Improved annotation of antibiotic resistance determinants reveals microbial resistomes cluster by ecology.

    Science.gov (United States)

    Gibson, Molly K; Forsberg, Kevin J; Dantas, Gautam

    2015-01-01

    Antibiotic resistance is a dire clinical problem with important ecological dimensions. While antibiotic resistance in human pathogens continues to rise at alarming rates, the impact of environmental resistance on human health is still unclear. To investigate the relationship between human-associated and environmental resistomes, we analyzed functional metagenomic selections for resistance against 18 clinically relevant antibiotics from soil and human gut microbiota as well as a set of multidrug-resistant cultured soil isolates. These analyses were enabled by Resfams, a new curated database of protein families and associated highly precise and accurate profile hidden Markov models, confirmed for antibiotic resistance function and organized by ontology. We demonstrate that the antibiotic resistance functions that give rise to the resistance profiles observed in environmental and human-associated microbial communities significantly differ between ecologies. Antibiotic resistance functions that most discriminate between ecologies provide resistance to β-lactams and tetracyclines, two of the most widely used classes of antibiotics in the clinic and agriculture. We also analyzed the antibiotic resistance gene composition of over 6000 sequenced microbial genomes, revealing significant enrichment of resistance functions by both ecology and phylogeny. Together, our results indicate that environmental and human-associated microbial communities harbor distinct resistance genes, suggesting that antibiotic resistance functions are largely constrained by ecology.

  6. 'Everything is everywhere: but the environment selects': ubiquitous distribution and ecological determinism in microbial biogeography.

    Science.gov (United States)

    O'Malley, Maureen A

    2008-09-01

    Recent discoveries of geographical patterns in microbial distribution are undermining microbiology's exclusively ecological explanations of biogeography and their fundamental assumption that 'everything is everywhere: but the environment selects'. This statement was generally promulgated by Dutch microbiologist Martinus Wilhelm Beijerinck early in the twentieth century and specifically articulated in 1934 by his compatriot, Lourens G. M. Baas Becking. The persistence of this precept throughout twentieth-century microbiology raises a number of issues in relation to its formulation and widespread acceptance. This paper will trace the conceptual history of Beijerinck's claim that 'everything is everywhere' in relation to a more general account of its theoretical, experimental and institutional context. His principle also needs to be situated in relationship to plant and animal biogeography, which, this paper will argue, forms a continuum of thought with microbial biogeography. Finally, a brief overview of the contemporary microbiological research challenging 'everything is everywhere' reveals that philosophical issues from Beijerinck's era of microbiology still provoke intense discussion in twenty-first century investigations of microbial biogeography.

  7. Detection of Microbial Growth on Polycyclic Aromatic Hydrocarbons in Microtiter Plates by Using the Respiration Indicator WST-1

    OpenAIRE

    Johnsen, Anders R.; Bendixen, Karen; Karlson, Ulrich

    2002-01-01

    We have developed a microtiter plate method for screening a large number of bacterial isolates for the ability to grow on different crystalline polycyclic aromatic hydrocarbons (PAHs). Growth on PAHs cannot easily be determined with standard growth assays because of the very low aqueous solubility and bioavailability of the PAHs. Our microtiter plate assay utilizes a new water-soluble respiration indicator, WST-1 {4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate}...

  8. Dietary microbial phytase exerts mixed effects on the gut health of tilapia: a possible reason for the null effect on growth promotion.

    Science.gov (United States)

    Hu, Jun; Ran, Chao; He, Suxu; Cao, Yanan; Yao, Bin; Ye, Yuantu; Zhang, Xuezhen; Zhou, Zhigang

    2016-06-01

    The present study evaluated the effects of dietary microbial phytase on the growth and gut health of hybrid tilapia (Oreochromis niloticus ♀×Oreochromis aureus ♂), focusing on the effect on intestinal histology, adhesive microbiota and expression of immune-related cytokine genes. Tilapia were fed either control diet or diet supplemented with microbial phytase (1000 U/kg). Each diet was randomly assigned to four groups of fish reared in cages (3×3×2 m). After 12 weeks of feeding, weight gain and feed conversion ratio of tilapia were not significantly improved by dietary microbial phytase supplementation. However, significantly higher level of P content in the scales, tighter and more regular intestinal mucosa folds were observed in the microbial phytase group and the microvilli density was significantly increased. The adhesive gut bacterial communities were strikingly altered by microbial phytase supplementation (0·41phytase, as indicated by the up-regulated intestinal expressions of the cytokine genes (tnf-α and tgf-β) and hsp70. In addition, the gut microvilli height was significantly decreased in the phytase group. These results indicate that dietary microbial phytase may exert mixed effects on hybrid tilapia, and can guide our future selection of phytases as aquafeed additives - that is, eliminating those that can stimulate intestinal inflammation.

  9. Factors that determine the evolution of high-growth businesses

    Directory of Open Access Journals (Sweden)

    Oriol Amat

    2013-09-01

    Full Text Available Objective: The study herein discusses research aimed at elucidating the factors that contribute to a business’ ability to maintain high growth. Design/Methodology/Perspective: The database from the Iberian Balance Sheet Analysis System (SABI, from its initials in Spanish was used to identify 250 industrial Catalonian businesses with high growth during 2004-2007. These companies participated in a survey on strategies and management practices; in 2013, they were re-analyzed to investigate the factors that contributed to continued growth for certain companies. Contributions: Through diverse statistical techniques, business policies related to quality, innovation, internationalization and finance were shown to influence business growth and sustainability over time. Limitations of the Research: This study focuses on industrial businesses at least ten years old in Catalonia; thus, the conclusions may differ in other geographic locations and economic sectors, as well as for smaller businesses. Practical Implications: Because growth is a measure of business success, identifying variables that contribute to high growth and its sustainability is helpful for businesses that seek to adopt effective policies. Social Implications: Generating employment is one of the primary contributions by high-growth businesses. For years with high unemployment, authorities may be interested in corporate policies that strengthen high-growth businesses. Originality/Added Value: High-growth businesses have been studied throughout the world, but this is the first study to investigate the evolution of businesses after a high-growth phase.

  10. High throughput nanostructure-initiator mass spectrometry screening of microbial growth conditions for maximal β-glucosidase production.

    Science.gov (United States)

    Cheng, Xiaoliang; Hiras, Jennifer; Deng, Kai; Bowen, Benjamin; Simmons, Blake A; Adams, Paul D; Singer, Steven W; Northen, Trent R

    2013-01-01

    Production of biofuels via enzymatic hydrolysis of complex plant polysaccharides is a subject of intense global interest. Microbial communities are known to express a wide range of enzymes necessary for the saccharification of lignocellulosic feedstocks and serve as a powerful reservoir for enzyme discovery. However, the growth temperature and conditions that yield high cellulase activity vary widely, and the throughput to identify optimal conditions has been limited by the slow handling and conventional analysis. A rapid method that uses small volumes of isolate culture to resolve specific enzyme activity is needed. In this work, a high throughput nanostructure-initiator mass spectrometry (NIMS)-based approach was developed for screening a thermophilic cellulolytic actinomycete, Thermobispora bispora, for β-glucosidase production under various growth conditions. Media that produced high β-glucosidase activity were found to be I/S + glucose or microcrystalline cellulose (MCC), Medium 84 + rolled oats, and M9TE + MCC at 45°C. Supernatants of cell cultures grown in M9TE + 1% MCC cleaved 2.5 times more substrate at 45°C than at all other temperatures. While T. bispora is reported to grow optimally at 60°C in Medium 84 + rolled oats and M9TE + 1% MCC, approximately 40% more conversion was observed at 45°C. This high throughput NIMS approach may provide an important tool in discovery and characterization of enzymes from environmental microbes for industrial and biofuel applications.

  11. High throughput nanostructure-initiator mass spectrometry screening of microbial growth conditions for maximal β-glucosidase production

    Directory of Open Access Journals (Sweden)

    Xiaoliang eCheng

    2013-12-01

    Full Text Available Production of biofuels via enzymatic hydrolysis of complex plant polysaccharides is a subject of intense global interest. Microbial communities are known to express a wide range of enzymes necessary for the saccharification of lignocellulosic feedstocks and serve as a powerful reservoir for enzyme discovery. However, the growth temperature and conditions that yield high cellulase activity vary widely, and the throughput to identify optimal conditions has been limited by the slow handling and conventional analysis. A rapid method that uses small volumes of isolate culture to resolve specific enzyme activity is needed. In this work, a high throughput nanostructure-initiator mass spectrometry (NIMS based approach was developed for screening a thermophilic cellulolytic actinomycete, Thermobispora bispora, for β-glucosidase production under various growth conditions. Media that produced high β-glucosidase activity were found to be I/S + glucose or microcrystalline cellulose (MCC, Medium 84 + rolled oats, and M9TE + MCC at 45 °C. Supernatants of cell cultures grown in M9TE + 1% MCC cleaved 2.5 times more substrate at 45 °C than at all other temperatures. While T. bispora is reported to grow optimally at 60 °C in Medium 84 + rolled oats and M9TE + 1% MCC, approximately 40% more conversion was observed at 45 °C. This high throughput NIMS approach may provide an important tool in discovery and characterization of enzymes from environmental microbes for industrial and biofuel applications.

  12. Transient negative biochar effects on plant growth are strongest after microbial species loss

    NARCIS (Netherlands)

    Hol, (Gera) W.H.G.; Vestergård, M.; Ten Hooven, F.C.; Duyts, H.; Van de Voorde, T.F.J.; Bezemer, T. Martijn

    2017-01-01

    Biochar has been explored as an organic amendment to improve soil quality and benefit plant growth. The overall positive effects of biochar on crop yields are generally attributed to abiotic changes, while the alternative causal pathway via changes in soil biota is unexplored. We compared plant

  13. Fermented soybean meal improves the growth performance, nutrient digestibility, and microbial flora in piglets

    Directory of Open Access Journals (Sweden)

    Lin Yuan

    2017-03-01

    Full Text Available In order to increase nutritive values of soybean meal (SBM, 3 species of microbes were used to ferment SBM. Through a 3 × 3 orthogonal design and parameter measurements of soybean peptide and anti-nutritional factor contents in the fermented soybean meal (FSBM, it was estimated that the best microbial proportion of Bacillus subtilis, Hansenula anomala and Lactobacillus casei was 2:1:2 for SBM fermentation (P  0.05. However, newly-weaned piglets (d 28–38 fed 10% FSBM and different levels of plasma protein obtained higher average daily gain (ADG and feed conversion ratio (FCR, compared with those without FSBM but with 6% plasma protein (P < 0.05. Piglets (d 38–68 fed diets supplemented with FSBM and soybean protein concentrate (SBPC at 3.75% and 7.5% respectively increased nutrient digestibility, fecal enzyme activity and lactic acid bacteria counts, and decreased fecal Escherichia coli counts (P < 0.05, compared with the control. These data indicated that FSBM had positive effects on nutrient digestibility and fecal microflora for piglets.

  14. Single-cell genomics reveal metabolic strategies for microbial growth and survival in an oligotrophic aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, Michael J.; Kennedy, David W.; Castelle, Cindy; Field, Erin; Stepanauskas, Ramunas; Fredrickson, Jim K.; Konopka, Allan

    2014-02-09

    Bacteria from the genus Pedobacter are a major component of microbial assemblages at Hanford Site and have been shown to significantly change in abundance in response to the subsurface intrusion of Columbia River water. Here we employed single cell genomics techniques to shed light on the physiological niche of these microorganisms. Analysis of four Pedobacter single amplified genomes (SAGs) from Hanford Site sediments revealed a chemoheterotrophic lifestyle, with the potential to exist under both aerobic and microaerophilic conditions via expression of both aa3­-type and cbb3-type cytochrome c oxidases. These SAGs encoded a wide-range of both intra-and extra­-cellular carbohydrate-active enzymes, potentially enabling the degradation of recalcitrant substrates such as xylan and chitin, and the utilization of more labile sugars such as mannose and fucose. Coupled to these enzymes, a diversity of transporters and sugar-binding molecules were involved in the uptake of carbon from the extracellular local environment. The SAGs were enriched in TonB-dependent receptors (TBDRs), which play a key role in uptake of substrates resulting from degradation of recalcitrant carbon. CRISPR-Cas mechanisms for resisting viral infections were identified in all SAGs. These data demonstrate the potential mechanisms utilized for persistence by heterotrophic microorganisms in a carbon-limited aquifer, and hint at potential linkages between observed Pedobacter abundance shifts within the 300 Area subsurface and biogeochemical shifts associated with Columbia River water intrusion.

  15. QUALITY OF NATIONAL ECONOMIC GROWTH: FACTORS AND DETERMINANTS

    Directory of Open Access Journals (Sweden)

    Nikolaj I. Komkov

    2015-01-01

    Full Text Available The subject / topic: TThe theme of this article is very relevant in the light of changes in the global geo-economic structure and changing the role and place ofRussiain world economic and geopolitical relations. The article deals with the basic aspects of national economic growth, which slowed down in the last three years. The main reason for slowing national economic growth is associated with the depletion of the reserves of the traditional export-oriented development of the Russian economy, as well as problems with sluggish innovative transformation. In this paper, based on a systematic analysis of economic processes and the interpretation of analytical data, addresses the general theoretical and methodological aspects of the quality of economic development, as well as practical guidelines and recommendations related to sustainable national socio-economic development in the context of external constraints.The purpose / objectives: The aim of the article is to analyze the theoretical and methodological aspects of the quality of economic development of the Russian economy, which happened in the face of economic sanctions. Objectives of the article: justify practical directions and recommendations related to sustainable national socio-economic development in the context of external constraints, determine the prospects for the economy of theRussian Federationin the conditions of the introduction of sectoral sanctions by Western countries. Methodology:Methodological basis of this article are the comparative and economic-statistical methods of analysis.The Results: The study revealed that the harsh environment (sanctions, depreciation of the ruble, and others. Require surgical intervention and adjustments not only the current socio-economic plans, but also to take urgent measures to ensure the development prospects. The most important decision is the degree of support advanced scientific and technical programs and the creation of new domestic

  16. Determinants of regional growth and convergence in Germany

    NARCIS (Netherlands)

    Weddige-Haaf, Katharina; Kool, Clemens

    2017-01-01

    In this paper, we analyse the sources of real per capita income growth and convergence in the 16 German states over the period 1995-2014 using a panel approach. The empirical analysis applies the popular growth – initial income equation. We augment the basic model specification with a trend term and

  17. Determinants of regional growth and convergence in Germany

    NARCIS (Netherlands)

    Haaf, K.; Kool, C.J.M.

    In this paper, we analyse the sources of real per capita income growth and convergence in the 16 German states over the period 1995-2014 using a panel approach. The empirical analysis applies the popular growth – initial income equation. We augment the basic model specification with a trend term and

  18. Growth and development and their environmental and biological determinants

    Directory of Open Access Journals (Sweden)

    Kelly da Rocha Neves

    2016-05-01

    Conclusion: The results showed a high prevalence of stunting and below‐average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas environmental variables were associated with development.

  19. Do the ban on use of anti-microbial growth promoter impact on technical change and the efficiency of slaughter-pig production

    DEFF Research Database (Denmark)

    Lawson, Lartey; Otto, Lars; Jensen, Peter Vig

    2005-01-01

    infections, and in effect stimu-lated the utilization of feedstuff and reduced the mortality rate. However, fears for increas-ing bacteria resistance with subsequent health hazards for humans and livestock has lead to societal debates about the pros and cons of its use in livestock production. Antibiotic......This study aims at investigating the effects of the ban on the use of anti-microbial growth promoters in the production of “Finishing Pigs” for slaughter. We investigate if the ban on the use of anti-microbial growth promoters has for specialised pig-producers altered the productivity of inputs......, technical change and the efficiency of production. This paper complements an earlier paper that investigated the impact of the ban on weaned-pig produc-tion. Background: The study is motivated by the fact that antimicrobial growth promoters have been known world wide to protect livestock from bacteria...

  20. Microbial background flora in small-scale cheese production facilities does not inhibit growth and surface attachment of Listeria monocytogenes.

    Science.gov (United States)

    Schirmer, B C T; Heir, E; Møretrø, T; Skaar, I; Langsrud, S

    2013-10-01

    The background microbiota of 5 Norwegian small-scale cheese production sites was examined and the effect of the isolated strains on the growth and survival of Listeria monocytogenes was investigated. Samples were taken from the air, food contact surfaces (storage surfaces, cheese molds, and brine) and noncontact surfaces (floor, drains, and doors) and all isolates were identified by sequencing and morphology (mold). A total of 1,314 isolates were identified and found to belong to 55 bacterial genera, 1 species of yeast, and 6 species of mold. Lactococcus spp. (all of which were Lactococcus lactis), Staphylococcus spp., Microbacterium spp., and Psychrobacter sp. were isolated from all 5 sites and Rhodococcus spp. and Chryseobacterium spp. from 4 sites. Thirty-two genera were only found in 1 out of 5 facilities each. Great variations were observed in the microbial background flora both between the 5 producers, and also within the various production sites. The greatest diversity of bacteria was found in drains and on rubber seals of doors. The flora on cheese storage shelves and in salt brines was less varied. A total of 62 bacterial isolates and 1 yeast isolate were tested for antilisterial activity in an overlay assay and a spot-on-lawn assay, but none showed significant inhibitory effects. Listeria monocytogenes was also co-cultured on ceramic tiles with bacteria dominating in the cheese production plants: Lactococcus lactis, Pseudomonas putida, Staphylococcus equorum, Rhodococcus spp., or Psychrobacter spp. None of the tested isolates altered the survival of L. monocytogenes on ceramic tiles. The conclusion of the study was that no common background flora exists in cheese production environments. None of the tested isolates inhibited the growth of L. monocytogenes. Hence, this study does not support the hypothesis that the natural background flora in cheese production environments inhibits the growth or survival of L. monocytogenes. Copyright © 2013 American

  1. Utility of Ochrobactrum anthropi YC152 in a Microbial Fuel Cell as an Early Warning Device for Hexavalent Chromium Determination

    Directory of Open Access Journals (Sweden)

    Guey-Horng Wang

    2016-08-01

    Full Text Available Fast hexavalent chromium (Cr(VI determination is important for environmental risk and health-related considerations. We used a microbial fuel cell-based biosensor inoculated with a facultatively anaerobic, Cr(VI-reducing, and exoelectrogenic Ochrobactrum anthropi YC152 to determine the Cr(VI concentration in water. The results indicated that O. anthropi YC152 exhibited high adaptability to pH, temperature, salinity, and water quality under anaerobic conditions. The stable performance of the microbial fuel cell (MFC-based biosensor indicated its potential as a reliable biosensor system. The MFC voltage decreased as the Cr(VI concentration in the MFC increased. Two satisfactory linear relationships were observed between the Cr(VI concentration and voltage output for various Cr(VI concentration ranges (0.0125–0.3 mg/L and 0.3–5 mg/L. The MFC biosensor is a simple device that can accurately measure Cr(VI concentrations in drinking water, groundwater, and electroplating wastewater in 45 min with low deviations (<10%. The use of the biosensor can help in preventing the violation of effluent regulations and the maximum allowable concentration of Cr(VI in water. Thus, the developed MFC biosensor has potential as an early warning detection device for Cr(VI determination even if O. anthropi YC152 is a possible opportunistic pathogen.

  2. The microbial content of raw and pasteurized cow milk as determined by molecular approaches.

    Science.gov (United States)

    Quigley, Lisa; McCarthy, Robert; O'Sullivan, Orla; Beresford, Tom P; Fitzgerald, Gerald F; Ross, R Paul; Stanton, Catherine; Cotter, Paul D

    2013-08-01

    The microbial composition of raw and pasteurized milk is assessed on a daily basis. However, many such tests are culture-dependent, and, thus, bacteria that are present at subdominant levels, or that cannot be easily grown in the laboratory, may be overlooked. To address this potential bias, we have used several culture-independent techniques, including flow cytometry, real-time quantitative PCR, and high-throughput DNA sequencing, to assess the microbial population of milk from a selection of commercial milk producers, pre- and postpasteurization. The combination of techniques employed reveals the presence of a previously unrecognized and diverse bacterial population in unpasteurized cow milk. Most notably, the use of high-throughput DNA sequencing resulted in several bacterial genera being identified in milk samples for the first time. These included Bacteroides, Faecalibacterium, Prevotella, and Catenibacterium. Our culture-independent analyses also indicate that the bacterial population of pasteurized milk is more diverse than previously appreciated, and that nonthermoduric bacteria within these populations are likely to be in a damaged, nonculturable form. It is thus apparent that the application of state-of-the-art approaches can provide a detailed insight into the bacterial composition of milk and could potentially be employed in the future to investigate the factors that influence the composition of these populations. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Microculture model studies on the effect of various gas atmospheres on microbial growth at different temperatures.

    Science.gov (United States)

    Eklund, T; Jarmund, T

    1983-08-01

    A microculture technique, employing 96-well tissue culture plates in plastic bags, was used to test the effect of different gas atmospheres (vacuum, air, nitrogen, and carbon dioxide) on the growth of Escherichia coli, Bacillus macerans, Salmonella typhimurium. Candida albicans, Lactobacillus plantarum, Pseudomonas/Acinetobacter/moraxella-group, Brochothrix thermosphacta and Yersinia enterocolitica at 2, 6, and 20 degrees C. In general, carbon dioxide was the most effective inhibitor. The inhibition increased with decreasing temperature. Only the combination of carbon dioxide and 2 degrees C provided complete inhibition of Broch. thermosphacta and Y. enterocolitica.

  4. Microbial Products and Biofertilizers in Improving Growth and Productivity of Apple - a Review.

    Science.gov (United States)

    Mosa, Walid F A E; Sas-Paszt, Lidia; Frąc, Mateusz; Trzciński, Paweł

    2016-08-26

    The excessive use of mineral fertilizers causes many negative consequences for the environment as well as potentially dangerous effects of chemical residues in plant tissues on the health of human and animal consumers. Bio-fertilizers are formulations of beneficial microorganisms, which upon application can increase the availability of nutrients by their biological activity and help to improve soil health. Microbes involved in the formulation of bio-fertilizers not only mobilize N and P but mediate the process of producing crops and foods naturally. This method avoids the use of synthetic chemical fertilizers and genetically modified organisms to influence the growth of crops. In addition to their role in enhancing the growth of the plants, biofertilizers can act as biocontrol agents in the rhizosphere at the same time. Biofertilizers are very safe for human, animal and environment. The use of Azotobacter, Azospirillum, Pseudomonas, Acetobacter, Burkholderia, Bacillus, Paenibacillus and some members of the Enterobacteriaceae is gaining worldwide importance and acceptance and appears to be the trend for the future.

  5. Microbial growth on oxalate by a route not involving glyoxylate carboligase

    Science.gov (United States)

    Blackmore, Maureen A.; Quayle, J. R.

    1970-01-01

    1. The metabolism of oxalate by the pink-pigmented organisms, Pseudomonas AM1, Pseudomonas AM2, Protaminobacter ruber and Pseudomonas extorquens has been compared with that of the non-pigmented Pseudomonas oxalaticus. 2. During growth on oxalate, all the organisms contain oxalyl-CoA decarboxylase, formate dehydrogenase and oxalyl-CoA reductase. This is consistent with oxidation of oxalate to carbon dioxide taking place via oxalyl-CoA, formyl-CoA and formate as intermediates, and also reduction of oxalate to glyoxylate taking place via oxalyl-CoA. 3. The pink-pigmented organisms, when grown on oxalate, contain l-serine–glyoxylate aminotransferase and hydroxypyruvate reductase but do not contain glyoxylate carboligase. The converse of this obtains in oxalate-grown Ps. oxalaticus. This indicates that, in contrast with Ps. oxalaticus, synthesis of C3 compounds from oxalate by the pink-pigmented organisms occurs by a variant of the `serine pathway' used by Pseudomonas AM1 during growth on C1 compounds. 4. Evidence in favour of this scheme is provided by the finding that a mutant of Pseudomonas AM1 that lacks hydroxypyruvate reductase is not able to grow on oxalate. PMID:5472155

  6. Antimicrobial activity of transition metal acid MoO3 prevents microbial growth on material surfaces

    International Nuclear Information System (INIS)

    Zollfrank, Cordt; Gutbrod, Kai; Wechsler, Peter; Guggenbichler, Josef Peter

    2012-01-01

    Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H 2 MoO 4 ), which is based on molybdenum trioxide (MoO 3 ). The modification of various materials (e.g. polymers, metals) with MoO 3 particles or sol–gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments. Highlights: ► The presented modifications of materials surfaces with MoO 3 are non-cytotoxic and decrease biofilm growth and bacteria transmission. ► The material is insensitive towards emerging resistances of bacteria. ► Strong potential to reduce spreading of infectious agents on inanimate surfaces.

  7. Inhibition of microbial growth by spice extracts and their effect of irradiation

    International Nuclear Information System (INIS)

    Ito, Hitoshi; Meixu, G.

    1994-01-01

    The antimicrobial activity of black pepper, rosemary and red pepper has been tested against 12 microorganisms. Alcoholic extracts of these spices were not exhibited strong activity against gram-negative bacteria in laboratory media. The growth of Bacillus subtilis and Clostridium botulinum type A was inhibited by 1% of black pepper, 0.5% rosemary and 0.03% red pepper. A little reduction of antimicrobial activity to B. subtilis was observed on extracts of gamma-irradiated black pepper or rosemary at 10 and 50 kGy. In the case of red pepper, irradiation of 10 or 50 kGy enhanced a little of antimicrobial activity to B. subtilis. Similar effect of irradiation was also observed on the inhibition of aflatoxin production by Aspergillus parasiticus in SL broth. (author)

  8. Effects of various weaning times on growth performance, rumen fermentation and microbial population of yellow cattle calves

    Science.gov (United States)

    Mao, Huiling; Xia, Yuefeng; Tu, Yan; Wang, Chong; Diao, Qiyu

    2017-01-01

    Objective This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3) or to early weaned (EW) group where calves were weaned when the feed intake of solid feed (starter) reached 500 g (EW500, n = 5), 750 g (EW750, n = 5), or 1,000 g (EW1,000, n = 5). Results Compared with NW, the EW treatments increased average daily gain (pcalves in EW750 had a higher (pintake than those in EW1,000 from wk 9 to the end of the trial. The concentrations of total volatile fatty acids in EW750 were greater than in NW and EW1,000 (p0.05), but changes in bacterial composition were found. Conclusion From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results. PMID:28423879

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-15

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

  10. Determinants of public health expenditure growth in Tanzania: an ...

    African Journals Online (AJOL)

    This paper identifies some major drivers of per capita public health expenditure growth in Tanzania using nationally representative annual data between 1995 and 2014. It used Bayesian model based on Markov Chain Monte Carlo (MCMC) simulation. The empirical result shows that both the real GDP per capita and ...

  11. Effect of Probiotic Bacteria on Microbial Host Defense, Growth, and Immune Function in Human Immunodeficiency Virus Type-1 Infection

    Directory of Open Access Journals (Sweden)

    Stig Bengmark

    2011-12-01

    Full Text Available The hypothesis that probiotic administration protects the gut surface and could delay progression of Human Immunodeficiency Virus type1 (HIV-1 infection to the Acquired Immunodeficiency Syndrome (AIDS was proposed in 1995. Over the last five years, new studies have clarified the significance of HIV-1 infection of the gut associated lymphoid tissue (GALT for subsequent alterations in the microflora and breakdown of the gut mucosal barrier leading to pathogenesis and development of AIDS. Current studies show that loss of gut CD4+ Th17 cells, which differentiate in response to normal microflora, occurs early in HIV-1 disease. Microbial translocation and suppression of the T regulatory (Treg cell response is associated with chronic immune activation and inflammation. Combinations of probiotic bacteria which upregulate Treg activation have shown promise in suppressing pro inflammatory immune response in models of autoimmunity including inflammatory bowel disease and provide a rationale for use of probiotics in HIV-1/AIDS. Disturbance of the microbiota early in HIV-1 infection leads to greater dominance of potential pathogens, reducing levels of bifidobacteria and lactobacillus species and increasing mucosal inflammation. The interaction of chronic or recurrent infections, and immune activation contributes to nutritional deficiencies that have lasting consequences especially in the HIV-1 infected child. While effective anti-retroviral therapy (ART has enhanced survival, wasting is still an independent predictor of survival and a major presenting symptom. Congenital exposure to HIV-1 is a risk factor for growth delay in both infected and non-infected infants. Nutritional intervention after 6 months of age appears to be largely ineffective. A meta analysis of randomized, controlled clinical trials of infant formulae supplemented with Bifidobacterium lactis showed that weight gain was significantly greater in infants who received B. lactis compared to

  12. Role of microbial inoculation and industrial by-product phosphogypsum in growth and nutrient uptake of maize (Zea mays L.) grown in calcareous soil.

    Science.gov (United States)

    Al-Enazy, Abdul-Aziz R; Al-Oud, Saud S; Al-Barakah, Fahad N; Usman, Adel Ra

    2017-08-01

    Alkaline soils with high calcium carbonate and low organic matter are deficient in plant nutrient availability. Use of organic and bio-fertilizers has been suggested to improve their properties. Therefore, a greenhouse experiment was conducted to evaluate the integrative role of phosphogypsum (PG; added at 0.0, 10, 30, and 50 g PG kg -1 ), cow manure (CM; added at 50 g kg -1 ) and mixed microbial inoculation (Incl.; Azotobacter chroococcum, and phosphate-solubilizing bacteria Bacillus megaterium var. phosphaticum and Pseudomonas fluorescens) on growth and nutrients (N, P, K, Fe, Mn, Zn and Cu) uptake of maize (Zea mays L.) in calcareous soil. Treatment effects on soil chemical and biological properties and the Cd and Pb availability to maize plants were also investigated. Applying PG decreased soil pH. The soil available P increased when soil was inoculated and/or treated with CM, especially with PG. The total microbial count and dehydrogenase activity were enhanced with PG+CM+Incl. Inoculated soils treated with PG showed significant increases in NPK uptake and maize plant growth. However, the most investigated treatments showed significant decreases in shoot micronutrients. Cd and Pb were not detected in maize shoots. Applying PG with microbial inoculation improved macronutrient uptake and plant growth. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Automated inference procedure for the determination of cell growth parameters

    Science.gov (United States)

    Harris, Edouard A.; Koh, Eun Jee; Moffat, Jason; McMillen, David R.

    2016-01-01

    The growth rate and carrying capacity of a cell population are key to the characterization of the population's viability and to the quantification of its responses to perturbations such as drug treatments. Accurate estimation of these parameters necessitates careful analysis. Here, we present a rigorous mathematical approach for the robust analysis of cell count data, in which all the experimental stages of the cell counting process are investigated in detail with the machinery of Bayesian probability theory. We advance a flexible theoretical framework that permits accurate estimates of the growth parameters of cell populations and of the logical correlations between them. Moreover, our approach naturally produces an objective metric of avoidable experimental error, which may be tracked over time in a laboratory to detect instrumentation failures or lapses in protocol. We apply our method to the analysis of cell count data in the context of a logistic growth model by means of a user-friendly computer program that automates this analysis, and present some samples of its output. Finally, we note that a traditional least squares fit can provide misleading estimates of parameter values, because it ignores available information with regard to the way in which the data have actually been collected.

  14. 11 Soil Microbial Biomass

    African Journals Online (AJOL)

    186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

  15. Nanoporous gold-based microbial biosensor for direct determination of sulfide.

    Science.gov (United States)

    Liu, Zhuang; Ma, Hanyue; Sun, Huihui; Gao, Rui; Liu, Honglei; Wang, Xia; Xu, Ping; Xun, Luying

    2017-12-15

    Environmental pollution caused by sulfide compounds has become a major problem for public health. Hence, there is an urgent need to explore a sensitive, selective, and simple sulfide detection method for environmental monitoring and protection. Here, a novel microbial biosensor was developed using recombinant Escherichia coli BL21 (E. coli BL21) expressing sulfide:quinone oxidoreductase (SQR) for sulfide detection. As an important enzyme involved in the initial step of sulfide metabolism, SQR oxidizes sulfides to polysulfides and transfers electrons to the electron transport chain. Nanoporous gold (NPG) with its unique properties was selected for recombinant E. coli BL21 cells immobilization, and then glassy carbon electrode (GCE) was modified by the resulting E. coli/NPG biocomposites to construct an E. coli/NPG/GCE bioelectrode. Due to the catalytic oxidation properties of NPG for sulfide, the electrochemical reaction of the E. coli/NPG/GCE bioelectrode is attributed to the co-catalysis of SQR and NPG. For sulfide detection, the E. coli/NPG/GCE bioelectrode showed a good linear response ranging from 50μM to 5mM, with a high sensitivity of 18.35μAmM -1 cm -2 and a low detection limit of 2.55μM. The anti-interference ability of the E. coli/NPG/GCE bioelectrode is better than that of enzyme-based inhibitive biosensors. Further, the E. coli/NPG/GCE bioelectrode was successfully applied to the detection of sulfide in wastewater. These unique properties potentially make the E. coli/NPG/GCE bioelectrode an excellent choice for reliable sulfide detection. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Determining the Mechanism of Low Temperature Graphene Growth

    Science.gov (United States)

    2014-05-27

    of three films (still on copper foils) in figure 2a, figure 2b and figure 2c, respectively. Figure 2a clearly shows the graphene flakes for a growth...shown in figure 3c. The coalesced graphene flakes fully cover the surface of the copper foil after synthesizing for exposure times longer than 30 s, as...Nickel and copper are the two most chosen catalysts to promote graphene formation [1, 16]. Due to the low carbon solubility in nickel or copper

  17. The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth.

    Science.gov (United States)

    Baćmaga, Małgorzata; Wyszkowska, Jadwiga; Kucharski, Jan

    2016-10-01

    Fungicides are considered to be effective crop protection chemicals in modern agriculture. However, they can also exert toxic effects on non-target organisms, including soil-dwelling microbes. Therefore, the environmental fate of fungicides has to be closely monitored. The aim of this study was to evaluate the influence of the Falcon 460 EC fungicide on microbial diversity, enzyme activity and resistance, and plant growth. Samples of sandy loam with pH KCl 7.0 were collected for laboratory analyses on experimental days 30, 60 and 90. Falcon 460 EC was applied to soil in the following doses: control (soil without the fungicide), dose recommended by the manufacturer, 30-fold higher than the recommended dose, 150-fold higher than the recommended dose and 300-fold higher than the recommended dose. The observed differences in the values of the colony development index and the eco-physiological index indicate that the mixture of spiroxamine, tebuconazole and triadimenol modified the biological diversity of the analyzed groups of soil microorganisms. Bacteria of the genus Bacillus and fungi of the genera Penicillium and Rhizopus were isolated from fungicide-contaminated soil. The tested fungicide inhibited the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. The greatest changes were induced by the highest fungicide dose 300-fold higher than the recommended dose. Dehydrogenases were most resistant to soil contamination. The Phytotoxkit test revealed that the analyzed fungicide inhibits seed germination capacity and root elongation. The results of this study indicate that excessive doses of the Falcon 460 EC fungicide 30-fold higher than the recommended dose to 300-fold higher than the recommended dose) can induce changes in the biological activity of soil. The analyzed microbiological and biochemical parameters are reliable indicators of the fungicide's toxic effects on soil quality.

  18. Parenting Styles: A Key Factor to Self Determination and Personal Growth of Adults

    Science.gov (United States)

    Aslam, Manika Arbab; Sultan, Sarwat

    2014-01-01

    The study was conducted to explore the impact of parenting styles of adolescents on their self-determination and personal growth. The data was collected from 300 adults evenly divided by gender, aged 23-38 years. To measure the parenting styles, level of self-determination and personal growth, the Caregivers Practices Report, Self Determination…

  19. Determinants of renewable energy growth: A global sample analysis

    International Nuclear Information System (INIS)

    Aguirre, Mariana; Ibikunle, Gbenga

    2014-01-01

    We investigate factors influencing country-level renewable energy growth by applying FEVD and PCSE estimation methods in a unique sample analysis. With a longer time series (1990–2010) and a broader sample size of countries (including Brazil, Russia, India, China and South Africa) than previous studies, our results reveal new insights. The results suggest that certain government-backed energy policies impede renewable energy investments, thus implying significant failures in policy design. These policies may be failing mainly because of uncertainty and the likelihood of discontinuity. Weak voluntary approaches are introduced in order to satisfy public demand for more sustainable investments and programmes; we find that these may have negative influences on the growth of renewables as well. The insight gained is consistent over the estimation methods employed. - Highlights: • Some public energy policies are shown to impede renewable energy investments; this implies failure in policy design. • Environmental concern is shown to drive renewables investment but energy security concerns do not seem to influence renewables investment. • Results suggest that countries are likely to reduce renewables commitments when under pressure to ensure energy supply. • Results seem to underscore the policy lobbying strength of the traditional energy mix industries

  20. Growth conditions determine the DNF2 requirement for symbiosis.

    Directory of Open Access Journals (Sweden)

    Fathi Berrabah

    Full Text Available Rhizobia and legumes are able to interact in a symbiotic way leading to the development of root nodules. Within nodules, rhizobia fix nitrogen for the benefit of the plant. These interactions are efficient because spectacularly high densities of nitrogen fixing rhizobia are maintained in the plant cells. DNF2, a Medicago truncatula gene has been described as required for nitrogen fixation, bacteroid's persistence and to prevent defense-like reactions in the nodules. This manuscript shows that a Rhizobium mutant unable to differentiate is not sufficient to trigger defense-like reactions in this organ. Furthermore, we show that the requirement of DNF2 for effective symbiosis can be overcome by permissive growth conditions. The dnf2 knockout mutants grown in vitro on agarose or Phytagel as gelling agents are able to produce nodules fixing nitrogen with the same efficiency as the wild-type. However, when agarose medium is supplemented with the plant defense elicitor ulvan, the dnf2 mutant recovers the fix- phenotype. Together, our data show that plant growth conditions impact the gene requirement for symbiotic nitrogen fixation and suggest that they influence the symbiotic suppression of defense reactions in nodules.

  1. Microbial Growth in the Magnesium- Chloride - Sodium- Sulphate Ion System: Implications for Habitability in Terrestrial and Extraterrestrial Salts

    Science.gov (United States)

    Loudon, C. M.; Aka, S.; Cockell, C. S.

    2017-12-01

    Icy moons in the outer solar system are key targets in the search for extra-terrestrial life as there is evidence that they harbour subsurface oceans. Observational evidence of icy moons such as Europa suggest that these likely brine oceans should be composed of chloride and sulphate salts. The effects of the ions that compose these salts on biology and how the interactions between them can create geochemical and geophysical barriers to life are poorly understood. Here we present an in depth study of four microorganisms grown in solutions with varying combinations of the magnesium- chloride- sodium- sulphate ions. We find that the ion composition of the brine solution can have a large effect on growth. Whilst the water activity must be permissible for growth we found that this alone could not predict the effects of the ions on growth, chaotropic effects and ion specific effects influenced by the specific physiology of organisms are also evident. For this reason we conclude that simply knowing which salts are present on icy moons is not sufficient information to determine their potential habitibility. A full sample of any brine ocean would need to be studied to fully determine the potential for biology on these outer solar system satellites.

  2. Aggregate Size and Architecture Determine Microbial Activity Balance for One-Stage Partial Nitritation and Anammox

    DEFF Research Database (Denmark)

    Vlaeminck, S.E.; Terada, Akihiko; Smets, Barth F.

    2010-01-01

    by the anoxic nitrite consumption rate. The smallest reactor A, B, and C aggregates were nitrite sources (NARR, > 1.7). Large reactor A and C aggregates were granules capable of autonomous nitrogen removal (NARR, 0.6 to 1.1) with internal AnAOB zones surrounded by an AerAOB rim. Around 50% of the autotrophic......AOB-rich aggregates (reactors B and C). The hypothesized granulation pathways include granule replication by division and budding and are driven by growth and/or decay based on species-specific physiology and by hydrodynamic shear and mixing....

  3. THE SUCCESS OF EMERGING CAPITAL MARKETS IN DETERMINING ECONOMIC GROWTH

    Directory of Open Access Journals (Sweden)

    Ion POHOAŢĂ

    2014-06-01

    Full Text Available Capital markets are regarded as “the barometer” of economic activity at the national level, but among emerging markets, the position of this segment in the economy is far from ideal. The answers that we try to offer are concerning the contribution of capital markets to the economic welfare of nations in transition from Central and Eastern Europe, using Granger causality tests. Our findings highlight that in this geographical area, the relation between capital markets and economic growth is a bidirectional one. However, although both the establishment of stock exchanges and their liberalization represented governments’ strategy of economic development, their objective was not fully achieved. Institutional transformations are required in order to attract foreign investors.

  4. Intellectual property: A strong determinant of economic growth

    Directory of Open Access Journals (Sweden)

    Munmun Rai

    2009-01-01

    Full Text Available The returns from almost all human endeavors can ultimately be translated into monetary gains. The past few years have seen increased attention paid to the strengthening of intellectual property rights due to globalization. The development of Intellectual property rights (IPR over the years has invariably brought an upsurge in the outlook of nations toward the aspect of societal and cultural growth, this being said with the preliminary assumption that economic growth has been the most affected realm and that it requires a separate spectrum of analysis. The artifacts between the IP regime and the national economy can be easily interpreted by the fact that India′s independence had itself brought an era where the enactment of the national IP laws were considered to stand on the touchstone of the market economy. The aim of the present article is to investigate the impact of a strong IP regime on the economic development of a nation and also a light is raised into Indian economy, and the creation of an efficient innovative system is discussed. A strong relation of the IPR with the pharma and biotech sectors has been discussed. Undoubtedly, the Intellectual property (IP systems must be developed so as to bring in socioeconomic well-being. The fact that a strong IPR actually provokes IPR infringements in many developing nations also seems to be an issue that needs to be analyzed while understanding the need of the former. The trade-off between unfair competition laws and IP also assumes importance of high magnitude and hence needs to be particularly emphasized. With the growing recognition of IPR, the importance of worldwide forums on IPR has been realized. Companies, universities, and industries want to protect their IPR internationally. In order to reach this goal, countries have signed numerous agreements and treaties.

  5. Determining of migraine prognosis using latent growth mixture models.

    Science.gov (United States)

    Tasdelen, Bahar; Ozge, Aynur; Kaleagasi, Hakan; Erdogan, Semra; Mengi, Tufan

    2011-04-01

    This paper presents a retrospective study to classify patients into subtypes of the treatment according to baseline and longitudinally observed values considering heterogenity in migraine prognosis. In the classical prospective clinical studies, participants are classified with respect to baseline status and followed within a certain time period. However, latent growth mixture model is the most suitable method, which considers the population heterogenity and is not affected drop-outs if they are missing at random. Hence, we planned this comprehensive study to identify prognostic factors in migraine. The study data have been based on a 10-year computer-based follow-up data of Mersin University Headache Outpatient Department. The developmental trajectories within subgroups were described for the severity, frequency, and duration of headache separately and the probabilities of each subgroup were estimated by using latent growth mixture models. SAS PROC TRAJ procedures, semiparametric and group-based mixture modeling approach, were applied to define the developmental trajectories. While the three-group model for the severity (mild, moderate, severe) and frequency (low, medium, high) of headache appeared to be appropriate, the four-group model for the duration (low, medium, high, extremely high) was more suitable. The severity of headache increased in the patients with nausea, vomiting, photophobia and phonophobia. The frequency of headache was especially related with increasing age and unilateral pain. Nausea and photophobia were also related with headache duration. Nausea, vomiting and photophobia were the most significant factors to identify developmental trajectories. The remission time was not the same for the severity, frequency, and duration of headache.

  6. Differences in microbial communities and performance between suspended and attached growth anaerobic membrane bioreactors treating synthetic municipal wastewater

    KAUST Repository

    Harb, Moustapha; Xiong, Yanghui; Guest, Jeremy; Amy, Gary L.; Hong, Pei-Ying

    2015-01-01

    operational taxonomic units (OTUs) most closely related to fermentative bacteria (e.g., Microbacter margulisiae) were dominant in the suspended biomass of the CSTR, accounting for 30% of the microbial community. Conversely, methanogenic archaea (e

  7. Fetal growth versus birthweight: the role of placenta versus other determinants.

    Directory of Open Access Journals (Sweden)

    Marie Cecilie Paasche Roland

    Full Text Available INTRODUCTION: Birthweight is used as an indicator of intrauterine growth, and determinants of birthweight are widely studied. Less is known about determinants of deviating patterns of growth in utero. We aimed to study the effects of maternal characteristics on both birthweight and fetal growth in third trimester and introduce placental weight as a possible determinant of both birthweight and fetal growth in third trimester. METHODS: The STORK study is a prospective cohort study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (age, parity, body mass index (BMI, gestational weight gain and fasting plasma glucose of birthweight and fetal growth estimated by biometric ultrasound measures were explored by linear regression models. Two models were fitted, one with only maternal characteristics and one which included placental weight. RESULTS: Placental weight was a significant determinant of birthweight. Parity, BMI, weight gain and fasting glucose remained significant when adjusted for placental weight. Introducing placental weight as a covariate reduced the effect estimate of the other variables in the model by 62% for BMI, 40% for weight gain, 33% for glucose and 22% for parity. Determinants of fetal growth were parity, BMI and weight gain, but not fasting glucose. Placental weight was significant as an independent variable. Parity, BMI and weight gain remained significant when adjusted for placental weight. Introducing placental weight reduced the effect of BMI on fetal growth by 23%, weight gain by 14% and parity by 17%. CONCLUSION: In conclusion, we find that placental weight is an important determinant of both birthweight and fetal growth. Our findings indicate that placental weight markedly modifies the effect of maternal determinants of both birthweight and fetal growth. The differential effect of third trimester glucose on birthweight and growth parameters illustrates that

  8. Intellectual property-A strong determinant of Economic Growth

    Directory of Open Access Journals (Sweden)

    Love k Singh

    2009-12-01

    Full Text Available

    The returns from almost all human endeavors can ultimately be translated into monetary gains. The past few years
    have seen increased attention to the strengthening of intellectual property rights due to globalization. The development
    of Intellectual property rights (IPR over the years has invariably brought an upsurge in the outlook of
    nations towards the aspect of societal and cultural growth, this being said with the preliminary assumption that
    economic growth has been the most affected realm and that it requires a separate spectrum of analysis. The artifacts
    between the IP regime and the national economy can be easily interpreted by the fact that India’s independence
    had itself brought an era where the enactment of the national IP laws were considered to stand on the touchstone
    of the market economy. The aim of the present paper is to investigate the impact of strong IP regime in the
    economic development of a nation and also a light is raised into Indian economy and creation for an efficient
    innovating system is discussed. A strong relation of IPR wity pharma sector and biotech sector has been discussed.
    Undoubtedly, IP systems must be developed so as to bring in socio-economic well-being. The fact that
    strong IPR actually provoke IPR infringements in many developing nations also seems to be an issue which needs
    to be analyzed while understanding the need of the former. The trade-off between unfair competition laws and IP
    also assumes importance of high magnitude and hence needs to be particularly emphasized. With the growing
    recognition of IPR, the importance of world wide forums on IPR is realized. Companies, universities, and industries
    want to protect their IPR internationally. In order to reach this goal, countries have signed numerous agreements
    and treaties.

  9. Determining the Diversity and Species Abundance Patterns in Arctic Soils using Rational Methods for Exploring Microbial Diversity

    Science.gov (United States)

    Ovreas, L.; Quince, C.; Sloan, W.; Lanzen, A.; Davenport, R.; Green, J.; Coulson, S.; Curtis, T.

    2012-12-01

    Arctic microbial soil communities are intrinsically interesting and poorly characterised. We have inferred the diversity and species abundance distribution of 6 Arctic soils: new and mature soil at the foot of a receding glacier, Arctic Semi Desert, the foot of bird cliffs and soil underlying Arctic Tundra Heath: all near Ny-Ålesund, Spitsbergen. Diversity, distribution and sample sizes were estimated using the rational method of Quince et al., (Isme Journal 2 2008:997-1006) to determine the most plausible underlying species abundance distribution. A log-normal species abundance curve was found to give a slightly better fit than an inverse Gaussian curve if, and only if, sequencing error was removed. The median estimates of diversity of operational taxonomic units (at the 3% level) were 3600-5600 (lognormal assumed) and 2825-4100 (inverse Gaussian assumed). The nature and origins of species abundance distributions are poorly understood but may yet be grasped by observing and analysing such distributions in the microbial world. The sample size required to observe the distribution (by sequencing 90% of the taxa) varied between ~ 106 and ~105 for the lognormal and inverse Gaussian respectively. We infer that between 5 and 50 GB of sequencing would be required to capture 90% or the metagenome. Though a principle components analysis clearly divided the sites into three groups there was a high (20-45%) degree of overlap in between locations irrespective of geographical proximity. Interestingly, the nearest relatives of the most abundant taxa at a number of most sites were of alpine or polar origin. Samples plotted on first two principal components together with arbitrary discriminatory OTUs

  10. What Determines Upscale Growth of Oceanic Convection into MCSs?

    Science.gov (United States)

    Zipser, E. J.

    2017-12-01

    Over tropical oceans, widely scattered convection of various depths may or may not grow upscale into mesoscale convective systems (MCSs). But what distinguishes the large-scale environment that favors such upscale growth from that favoring "unorganized", scattered convection? Is it some combination of large-scale low-level convergence and ascending motion, combined with sufficient instability? We recently put this to a test with ERA-I reanalysis data, with disappointing results. The "usual suspects" of total column water vapor, large-scale ascent, and CAPE may all be required to some extent, but their differences between large MCSs and scattered convection are small. The main positive results from this work (already published) demonstrate that the strength of convection is well correlated with the size and perhaps "organization" of convective features over tropical oceans, in contrast to tropical land, where strong convection is common for large or small convective features. So, important questions remain: Over tropical oceans, how should we define "organized" convection? By size of the precipitation area? And what environmental conditions lead to larger and better organized MCSs? Some recent attempts to answer these questions will be described, but good answers may require more data, and more insights.

  11. Patterns of Growth in Early Childhood and Infectious Disease and Nutritional Determinants.

    Science.gov (United States)

    Black, Robert E

    2017-01-01

    The physical growth of young children in low- and middle-income countries is reduced compared to international standards. The deviations in growth in both weight and height are greatest in the first 2 years of life and this has serious consequences for child mortality, development, adult stature, and health. The determinants of these patterns of growth faltering include intergenerational factors, such as maternal height, short birth interval, and conditions in pregnancy, including maternal underweight and anemia. These factors contribute to fetal growth restriction and premature delivery, which put many infants on a different growth trajectory. Postnatal exposure to microbes resulting in diarrhea and febrile infectious diseases and poor quality diet further compromise growth. Determinants of growth faltering after birth vary by setting and are not independent of each other. For example, the adverse effects of diarrhea on growth may be mitigated by a high-quality diet. Global estimates suggest that 25% of stunting can be attributed to fetal growth restriction and even more in countries in South Asia with a high prevalence of low birth weight. Infectious diseases may contribute a similar amount and subclinical enteric infections can result in intestinal dysfunction with adverse effects on nutrition and growth. Dietary factors, especially consumption of complementary foods of insufficient quality, have a paramount role in growth faltering in the critical period of infancy. © 2017 Nestec Ltd., Vevey/S. Karger AG, Basel.

  12. Determination of charge transfer resistance and capacitance of microbial fuel cell through a transient response analysis of cell voltage.

    Science.gov (United States)

    Ha, Phuc Thi; Moon, Hyunsoo; Kim, Byung Hong; Ng, How Yong; Chang, In Seop

    2010-03-15

    An alternative method for determining the charge transfer resistance and double-layer capacitance of microbial fuel cells (MFCs), easily implemented without a potentiostat, was developed. A dynamic model with two parameters, the charge transfer resistance and double-layer capacitance of electrodes, was derived from a linear differential equation to depict the current generation with respect to activation overvoltage. This model was then used to fit the transient cell voltage response to the current step change during the continuous operation of a flat-plate type MFC fed with acetate. Variations of the charge transfer resistance and the capacitance value with respect to the MFC design conditions (biocatalyst existence and electrode area) and operating parameters (acetate concentration and buffer strength in the catholyte) were then determined to elucidate the validity of the proposed method. This model was able to describe the dynamic behavior of the MFC during current change in the activation loss region; having an R(2) value of over 0.99 in most tests. Variations of the charge transfer resistance value (thousands of Omega) according to the change of the design factors and operational factors were well-correlated with the corresponding MFC performances. However, though the capacitance values (approximately 0.02 F) reflected the expected trend according to the electrode area change and catalyst property, they did not show significant variation with changes in either the acetate concentration or buffer strength. (c) 2009 Elsevier B.V. All rights reserved.

  13. Problems in the radioimmunological determination of growth hormones

    International Nuclear Information System (INIS)

    Gottsmann, M.

    1973-01-01

    Four radioimmunological methods for the determination of serum HGH are compared with regard to sensitivity, precision, and specifity: the double-antibody method, the salt precipitation method, the coated-charcoal absorption method, and the solid phase method. The effects of serum proteins, complement fractions, haemolysis, and serum dilution on these methods are investigated. Furthermore, two HGH antibody preparations are investigated with regard to their cross reactions with LH, TSH, HCS, BPr, and HPr. In the HGH and HCS double-antibody systems, the serum dilution does not influence the test. In normal persons, no difference can be found between the serum HGH level of the cranial bulb of the jugular vein and that of a cubital vein, while patients with acromegaly exhibit a marked difference. In one patient who suffers from a Forbes-Albright syndrome with a prolactin-secreting tumour of the pituitary gland, the secretion of LH and HGH is reduced while the ACTH and TSH secretion is not affected. (BSC/AK) [de

  14. Morphology and ultrastructure of epilithic versus cryptic, microbial growth in lower Cambrian phosphorites from the Montagne Noire, France.

    Science.gov (United States)

    Alvaro, J J; Clausen, S

    2010-03-01

    The lower Cambrian grainy phosphorites of the northern Montagne Noire occur interbedded with grey to black, laminated to massive shales and limestones deposited along the edge of a continental shelf, associated with slope-related facies and unstable substrates. The concentration of phosphate took place by repeated alternations of low sedimentation rates and condensation (hardgrounds), in situ early-diagenetic precipitation of fluorapatite, winnowing and polyphase reworking of previously phosphatized skeletons and hardground-derived clasts. The succession of repeated cycles of sedimentation, phosphate concentration, and reworking led to multi-event phosphate deposits rich in allochthonous particles. Phosphogenesis was primarily mediated by microbial activity, which is evidenced by the abundance of phosphatized putative microbial remains. These occur as smooth and segmented filaments, sheaths, and ovoid-shaped coccoids. These simple morphologies commonly form composite frameworks as a result of their aggregation and entanglement, leading to the record of biofilms, microbial mats, and complex networks. These infested the calcitic skeletonized microfossils that littered the substrate. Microbial activity evidences epilithic (anisotropic coatings on skeletons), euendolithic (perforating skeletal walls), and cryptoendolithic (lining inter- and intraparticulate pores) strategies, the latter dominated by bundles of filaments and globular clusters that grew along the cavities of helcionellids and hyoliths. According to their epilithic versus cryptic strategies, microbial populations that penetrated and dwelled inside hard skeletal substrates show different network and colonial morphologies. These early Cambrian shell concentrations were the loci of a stepwise colonization made by saprophytic to mutualistic, cyanobacterial-fungal consortia. Their euendolithic and cryptoendolithic ecological niches provided microbial refugia to manage the grazing impact mainly led by metazoans.

  15. Sensitive double-antibody method for simultaneous determination of insulin and growth hormone

    International Nuclear Information System (INIS)

    Koparanova, O.; Sotirov, G.; Tyrkolev, N.

    1982-01-01

    A method is described for simultaneous determination of insulin and growth hormone in one sample, using double-antibody technique. The method is characterized by appreciable sensitivity (2.5 μE/ml for insulin and a.2 ng/ml for growth hormone), exactness (variation quotient 6-16 per cent) and reproducibility (96.9-117 per cent). There was no statistically significant difference in the insulin and growth hormone values of the same sera, determined by the here suggested and the standard methods. The necessary test material for examination of either hormone is minimal (0.2 ml). One may thus extend the possibilities for radioimmunologic determination of insulin and growth hormone, when only minor amounts of serum or other biological fluid are available. The method is also less time consuming. Results are reported of statistical processing of an experimental model and different sera determined by the standard method and the one described by the authors. (author)

  16. Life in Ice: Microbial Growth Dynamics and Greenhouse Gas Production During Winter in a Thermokarst Bog Revealed by Stable Isotope Probing Targeted Metagenomics

    Science.gov (United States)

    Blazewicz, S.; White, R. A., III; Tas, N.; Euskirchen, E. S.; Mcfarland, J. W.; Jansson, J.; Waldrop, M. P.

    2016-12-01

    Permafrost contains a reservoir of frozen C estimated to be twice the size of the current atmospheric C pool. In response to changing climate, permafrost is rapidly warming which could result in widespread seasonal thawing. When permafrost thaws, soils that are rich in ice and C often transform into thermokarst wetlands with anaerobic conditions and significant production of atmospheric CH4. While most C flux research in recently thawed permafrost concentrates on the few summer months when seasonal thaw has occurred, there is mounting evidence that sizeable portions of annual CO2 and CH4 efflux occurs over winter or during a rapid burst of emissions associated with seasonal thaw. A potential mechanism for such efflux patterns is microbial activity in frozen soils over winter where gasses produced are partially trapped within ice until spring thaw. In order to better understand microbial transformation of soil C to greenhouse gas over winter, we applied stable isotope probing (SIP) targeted metagenomics combined with process measurements and field flux data to reveal activities of microbial communities in `frozen' soil from an Alaskan thermokarst bog. Field studies revealed build-up of CO2 and CH4 in frozen soils suggesting that microbial activity persisted throughout the winter in soils poised just below the freezing point. Laboratory incubations designed to simulate in-situ winter conditions (-1.5 °C and anaerobic) revealed continuous CH4 and CO2 production. Strikingly, the quantity of CH4 produced in 6 months in frozen soil was equivalent to approximately 80% of CH4 emitted during the 3 month summer `active' season. Heavy water SIP targeted iTag sequencing revealed growing bacteria and archaea in the frozen anaerobic soil. Growth was primarily observed in two bacterial phyla, Firmicutes and Bacteroidetes, suggesting that fermentation was likely the major C mineralization pathway. SIP targeted metagenomics facilitated characterization of the primary metabolic

  17. Novel co-culture plate enables growth dynamic-based assessment of contact-independent microbial interactions.

    Directory of Open Access Journals (Sweden)

    Thomas J Moutinho

    Full Text Available Interactions between microbes are central to the dynamics of microbial communities. Understanding these interactions is essential for the characterization of communities, yet challenging to accomplish in practice. There are limited available tools for characterizing diffusion-mediated, contact-independent microbial interactions. A practical and widely implemented technique in such characterization involves the simultaneous co-culture of distinct bacterial species and subsequent analysis of relative abundance in the total population. However, distinguishing between species can be logistically challenging. In this paper, we present a low-cost, vertical membrane, co-culture plate to quantify contact-independent interactions between distinct bacterial populations in co-culture via real-time optical density measurements. These measurements can be used to facilitate the analysis of the interaction between microbes that are physically separated by a semipermeable membrane yet able to exchange diffusible molecules. We show that diffusion across the membrane occurs at a sufficient rate to enable effective interaction between physically separate cultures. Two bacterial species commonly found in the cystic fibrotic lung, Pseudomonas aeruginosa and Burkholderia cenocepacia, were co-cultured to demonstrate how this plate may be implemented to study microbial interactions. We have demonstrated that this novel co-culture device is able to reliably generate real-time measurements of optical density data that can be used to characterize interactions between microbial species.

  18. Planned growth as a determinant of the markup: the case of Slovenian manufacturing

    Directory of Open Access Journals (Sweden)

    Maks Tajnikar

    2009-11-01

    Full Text Available The paper follows the idea of heterodox economists that a cost-plus price is above all a reproductive price and growth price. The authors apply a firm-level model of markup determination which, in line with theory and empirical evidence, contains proposed firm-specific determinants of the markup, including the firm’s planned growth. The positive firm-level relationship between growth and markup that is found in data for Slovenian manufacturing firms implies that retained profits gathered via the markup are an important source of growth financing and that the investment decisions of Slovenian manufacturing firms affect their pricing policy and decisions on the markup size as proposed by Post-Keynesian theory. The authors thus conclude that at least a partial trade-off between a firm’s growth and competitive outcome exists in Slovenian manufacturing.

  19. Determination of plant growth rate and growth temperature range from measurement of physiological parameters

    Science.gov (United States)

    R. S. Criddle; B. N. Smith; L. D. Hansen; J. N. Church

    2001-01-01

    Many factors influence species range and diversity, but temperature and temperature variability are always major global determinants, irrespective of local constraints. On a global scale, the ranges of many taxa have been observed to increase and their diversity decrease with increasing latitude. On a local scale, gradients in species distribution are observable with...

  20. Work Tasks as Determinants of Grain Dust and Microbial Exposure in the Norwegian Grain and Compound Feed Industry.

    Science.gov (United States)

    Straumfors, Anne; Heldal, Kari Kulvik; Wouters, Inge M; Eduard, Wijnand

    2015-07-01

    The grain and compound feed industry entails inevitable risks of exposure to grain dust and its microbial content. The objective of this study was therefore to investigate task-dependent exposure differences in order to create knowledge basis for awareness and exposure reducing measures in the Norwegian grain and compound feed industry. A total of 166 samples of airborne dust were collected by full-shift personal sampling during work in 20 grain elevators and compound feed mills during one autumn season and two winter seasons. The personal exposure to grain dust, endotoxins, β-1→3-glucans, bacteria, and fungal spores was quantified and used as individual outcomes in mixed models with worker nested in company as random effect and different departments and tasks as fixed effects. The exposure levels were highest in grain elevator departments. Exposure to endotoxins was particularly high. Tasks that represented the highest and lowest exposures varied depending on the bioaerosol component. The most important determinants for elevated dust exposure were cleaning and process controlling. Cleaning increased the dust exposure level by a factor of 2.44 of the reference, from 0.65 to 1.58mg m(-3), whereas process controlling increased the dust exposure level by a factor of 2.97, from 0.65 to 1.93mg m(-3). Process controlling was associated with significantly less grain dust exposure in compound feed mills and the combined grain elevators and compound feed mills, than in grain elevators. The exposure was reduced by a factor of 0.18 and 0.22, from 1.93 to 0.34mg m(-3) and to 0.42mg m(-3), respectively, compared with the grain elevators. Inspection/maintenance, cleaning, and grain rotation and emptying were determinants of higher exposure to both endotoxin and β-1→3-glucans. Seed winnowing was in addition a strong determinant for endotoxin, whereas mixing of animal feed implied higher β-1→3-glucan exposure. Cleaning was the only task that contributed significantly to

  1. Proceedings of the 8. International Symposium on Microbial Ecology : microbial biosystems : new frontiers

    International Nuclear Information System (INIS)

    Bell, C.R.; Brylinsky, M.; Johnson-Green, P.

    2000-01-01

    A wide range of disciplines were presented at this conference which reflected the importance of microbial ecology and provided an understanding of the factors that determine the growth and activities of microorganisms. The conference attracted 1444 delegates from 54 countries. The research emerging from the rapidly expanding frontier of microbial ecosystems was presented in 62 oral presentation and 817 poster presentations. The two volumes of these proceedings presented a total of 27 areas in microbial ecology, some of which included terrestrial biosystems, aquatic, estuarine, surface and subsurface microbial ecology. Other topics included bioremediation, microbial ecology in industry and microbial ecology of oil fields. Some of the papers highlighted the research that is underway to determine the feasibility of using microorganisms for enhanced oil recovery (EOR). Research has shown that microbial EOR can increase production at lower costs than conventional oil recovery. The use of bacteria has also proven to be a feasible treatment method in the biodegradation of hydrocarbons associated with oil spills. refs., tabs., figs

  2. Internal and External Determinants of Economic Growth: A closer look at Pakistan’s Economy

    Directory of Open Access Journals (Sweden)

    Muhammad Jamil

    2013-09-01

    Full Text Available This study aims to investigate the impact of internal and external determinants of economic growth on the economic growth of Pakistan. Major internal determinants include stock of physical capital and developmental expenditures, while external determinants include trade openness and real effective exchange rate. In doing so, study utilizes the annual time series data from 1972 to 2011. Advanced Autoregressive Distributed Lag model (ARDL approach has been employed for co-integration and error correction model (ECM for short-run results. Empirical investigations indicate that developmental expenditures, physical capital and trade openness are positively correlated with economic growth in long run, while real effective exchange rate negatively and significantly affect economic growth in long run in case of Pakistan.

  3. Comparison of signaling interactions determining annual and perennial plant growth in response to low temperature

    Directory of Open Access Journals (Sweden)

    Astrid eWingler

    2015-01-01

    Full Text Available Low temperature inhibits plant growth despite the fact that considerable rates of photosynthetic activity can be maintained. Instead of lower rates of photosynthesis, active inhibition of cell division and expansion is primarily responsible for reduced growth. This results in sink limitation and enables plants to accumulate carbohydrates that act as compatible solutes or are stored throughout the winter to enable re-growth in spring. Regulation of growth in response to temperature therefore requires coordination with carbon metabolism, e.g. via the signaling metabolite trehalose-6-phosphate. The phytohormones gibberellins (GA and jasmonate (JA play an important role in regulating growth in response to temperature. Growth restriction at low temperature is mainly mediated by DELLA proteins, whose degradation is promoted by GA. For annual plants, it has been shown that the GA/DELLA pathway interacts with JA signaling and C-repeat binding factor (CBF dependent cold acclimation, but these interactions have not been explored in detail for perennials. Growth regulation in response to seasonal factors is, however, particularly important in perennials, especially at high latitudes. In autumn, growth cessation in trees is caused by shortening of the daylength in interaction with phytohormone signaling. In perennial grasses seasonal differences in the sensitivity to GA may enable enhanced growth in spring. This review provides an overview of the signaling interactions that determine plant growth at low temperature and highlights gaps in our knowledge, especially concerning the seasonality of signaling responses in perennial plants.

  4. Phosphorus status and microbial community of paddy soil with the growth of annual ryegrass (Lolium multiflorum Lam.) under different phosphorus fertilizer treatments*

    Science.gov (United States)

    Guo, Hai-chao; Wang, Guang-huo

    2009-01-01

    Annual ryegrass (Lolium multiflorum Lam.) was grown in paddy soil in pots under different phosphorus (P) fertilizer treatments to investigate changes of P fractions and microbial community of the soil. The treatments included Kunyang phosphate rock (KPR) applications at 50 mg P/kg (KPR50) and 250 mg P/kg (KPR250), mono-calcium phosphate (MCP) application at 50 mg P/kg (MCP50), and the control without P application. The results showed that KPR50, KPR250, and MCP50 applications significantly increased the dry weight of the ryegrass by 13%, 38%, and 55%, and increased P uptake by 19%, 135%, and 324%, respectively. Compared with MCP50, the relative effectiveness of KPR50 and KPR250 treatments in ryegrass production was about 23% and 68%, respectively. After one season of ryegrass growth, the KPR50, KPR250, and MCP50 applications increased soil-available P by 13.4%, 26.8%, and 55.2%, respectively. More than 80% of the applied KPR-P remained as HCl-P fraction in the soil. Phospholipid fatty acid (PLFA) analysis showed that the total and bacterial PLFAs were significantly higher in the soils with KPR250 and MCP50 treatments compared with KPR50 and control. The latter had no significant difference in the total or bacterial PLFAs. The KPR50, KPR250, and MCP50 treatments increased fungal PLFA by 69%, 103%, and 69%, respectively. Both the principal component analysis and the cluster analysis of the PLFA data suggest that P treatments altered the microbial community composition of the soils, and that P availability might be an important contributor to the changes in the microbial community structure during the ryegrass growth in the paddy soils. PMID:19817001

  5. Determinants of infant growth: Evidence from Hong Kong's "Children of 1997" birth cohort.

    Science.gov (United States)

    Hui, L L; Leung, Gabriel M; Cowling, Benjamin J; Lam, T H; Schooling, C Mary

    2010-11-01

    A high rate of infant growth may be associated with adult cardiovascular disease. We investigated factors associated with infant weight growth in a large sample from the recently transitioned population of Hong Kong. We used a nonlinear shape invariant model with random effects among 5949 term, singletons (77% follow-up) from a population-representative Hong Kong Chinese birth cohort "Children of 1997" to investigate factors associated with weight growth in the first year of life. Overall birth weight was lower but infant growth was more rapid than the 2006 WHO standards. Shorter gestation and lower birth order were associated with lower birth weight and faster infant growth. Female sex, maternal smoking in pregnancy, and a mother born in Hong Kong were associated with lower birth weight, but not with faster growth. Higher maternal education was associated with faster infant growth, grades 10-11 (1.03, 95% confidence interval [CI] = 1.03-1.05), greater than or equal to grade12 (1.07, CI = 1.04-1.09) compared with less than or equal to grade 9. Infant growth may respond more rapidly to socio-economic development than birth weight. Whether mother's education is associated with rapid infant growth via current conditions or her own "constitution" is unclear, nevertheless we believe this study illustrates the importance of contextually specific research for understanding the determinants of population health. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. History of adaptation determines short-term shifts in performance and community structure of hydrogen-producing microbial communities degrading wheat straw.

    Science.gov (United States)

    Valdez-Vazquez, Idania; Morales, Ana L; Escalante, Ana E

    2017-11-01

    This study addresses the question of ecological interest for the determination of structure and diversity of microbial communities that degrade lignocellulosic biomasses to produce biofuels. Two microbial consortia with different history, native of wheat straw (NWS) and from a methanogenic digester (MD) fed with cow manure, were contrasted in terms of hydrogen performance, substrate disintegration and microbial diversity. NWS outperformed the hydrogen production rate of MD. Microscopic images revealed that NWS acted on the cuticle and epidermis, generating cellulose strands with high crystallinity, while MD degraded deeper layers, equally affecting all polysaccharides. The bacterial composition markedly differed according to the inocula origin. NWS almost solely comprised hydrogen producers of the phyla Firmicutes and Proteobacteria, with 38% members of Enterococcus. After hydrogen fermentation, NWS comprised 8% Syntrophococcus, an acetogen that cleaves aryl ethers of constituent groups on the aromatic components of lignin. Conversely, MD comprised thirteen phyla, primarily including Firmicutes with H 2 -producing members, and Bacteroidetes with non-H 2 -producing members, which reduced the hydrogen performance. Overall, the results of this study provide clear evidence that the history of adaptation of NWS enhanced the hydrogen performance from untreated wheat straw. Further, native wheat straw communities have the potential to refine cellulose fibers and produce biofuels simultaneously. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. An inverse modeling procedure to determine particle growth and nucleation rates from measured aerosol size distributions

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

    Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.

  8. An Empirical Analysis of the Determinants of Economic Growth in the Western Balkans

    Directory of Open Access Journals (Sweden)

    Fetai Besnik Taip

    2017-06-01

    Full Text Available The objective of this paper is to assess the main determinants and the policies that affect economic growth in the Western Balkan over the period 1994 to 2015. It employs techniques such as pooled OLS, fixed and random effects model, and Hausman-Taylor model with instrumental variables (IV. The study shows evidence of conditional convergence, indicating the need for an upward move in the steady state level. The results show that foreign direct investments, gross savings and domestic credit to the private sector have a positive effect on per capita growth. On the other hand, initial level of per capita growth, corruption, unemployment, and general government final consumption, have a negative relationship with per capita growth. The study also shows a puzzling result, that schooling is not a significant factor for growth in Western Balkans. The study also highlights the relevance of attracting more foreign direct investments and reduction in corruption.

  9. A test procedure for determining the influence of stress ratio on fatigue crack growth

    Science.gov (United States)

    Fitzgerald, J. H.; Wei, R. P.

    1974-01-01

    A test procedure is outlined by which the rate of fatigue crack growth over a range of stress ratios and stress intensities can be determined expeditiously using a small number of specimens. This procedure was developed to avoid or circumvent the effects of load interactions on fatigue crack growth, and was used to develop data on a mill annealed Ti-6Al-4V alloy plate. Experimental data suggest that the rates of fatigue crack growth among the various stress ratios may be correlated in terms of an effective stress intensity range at given values of K max. This procedure is not to be used, however, for determining the corrosion fatigue crack growth characteristics of alloys when nonsteady-state effects are significant.

  10. EVA Suit Microbial Leakage Investigation

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during...

  11. Robust Determinants of Growth in Asian Developing Economies: A Bayesian Panel Data Model Averaging Approach

    OpenAIRE

    LEON-GONZALEZ, Roberto; VINAYAGATHASAN, Thanabalasingam

    2013-01-01

    This paper investigates the determinants of growth in the Asian developing economies. We use Bayesian model averaging (BMA) in the context of a dynamic panel data growth regression to overcome the uncertainty over the choice of control variables. In addition, we use a Bayesian algorithm to analyze a large number of competing models. Among the explanatory variables, we include a non-linear function of inflation that allows for threshold effects. We use an unbalanced panel data set of 27 Asian ...

  12. INNOVATION POTENTIAL AS A DETERMINING FACTOR IN THE GROWTH OF COMPETITIVE ADVANTAGES BUILDING PRODUCTS

    OpenAIRE

    T. U. Levitsky; A. M. Esetova

    2014-01-01

    It is stipulated that the construction company, chosen the strategy of economic growth, should have some competitive advantages, determining opportunities for sustainable development and effective improving, and operational efficiency increase. One of the factors of the competitiveness increase of construction products is the innovative potential of construction industry. Methodical approaches to the evaluation of innovative capacity and its effect on the growth of competitive advantages have...

  13. INNOVATION POTENTIAL AS A DETERMINING FACTOR IN THE GROWTH OF COMPETITIVE ADVANTAGES BUILDING PRODUCTS

    Directory of Open Access Journals (Sweden)

    T. U. Levitsky

    2014-01-01

    Full Text Available It is stipulated that the construction company, chosen the strategy of economic growth, should have some competitive advantages, determining opportunities for sustainable development and effective improving, and operational efficiency increase. One of the factors of the competitiveness increase of construction products is the innovative potential of construction industry. Methodical approaches to the evaluation of innovative capacity and its effect on the growth of competitive advantages have been proposed. 

  14. Maternal determinants of intrauterine growth restriction in Goa, India: a case-control study

    Directory of Open Access Journals (Sweden)

    DD Motghare

    2014-01-01

    Full Text Available Objective: To study the maternal determinants of intrauterine growth restriction. Methods: A case-control study was conducted at a tertiary care Hospital in the year 2009. Ninety eight cases of intrauterine growth restriction were compared to 98 controls, matched for newborns sex and type of delivery. Data was collected by interviewing the mother using a structured pretested schedule and perusal of antenatal records. Intrauterine growth restriction was defined as occurring if birth weight of the newborn is below 10th percentile for gestational age on the intrauterine growth curve. Data was analyzed using SPSS software version 17 package. Percentages, odds ratios with 95% CI and multiple logistic regression analysis were used wherever appropriate. Results: Maternal age, education, socioeconomic status and number of antenatal visits were found to be the significant socio-demographic factors associated with Intrauterine growth restriction while, maternal height, parity, previous spontaneous abortion, direct obstetric morbidity, indirect obstetric morbidity and anemia were the maternal biological factors found to be significantly associated on bivariate analysis. Multiple logistic regression analysis identified parity, previous spontaneous abortion, direct obstetric morbidity, indirect obstetric morbidity and antenatal visits as significant maternal determinants of intrauterine growth restriction. Conclusions: A focus on good antenatal care, especially on high risk pregnancies would go a long way in reducing the problem of intrauterine growth restriction in the community thereby ensuring a safe and healthy future for our youngest generation.

  15. Atacama Desert: Determination of two new extremophilic microbial model systems for space exploration and astrobiology studies - data from a large-scale transect study

    Science.gov (United States)

    Boy, Diana; Godoy, Roberto; Guggenberger, Georg; Möller, Ralf; Boy, Jens

    2017-04-01

    The hyper-arid region of Yungay in the Atacama Desert in Chile is believed to be the driest place on Earth thus harboring the most desiccation-resistant microorganisms. Hence the search for new extremophilic model organisms is traditionally limited to this rather narrow strip. However, it is not clear whether Yungay is indeed the most arid place, as this should be the one with the lowest soil organic carbon (SOC) stock and soil water (SW) content. Therefore we tested soil samples from a humidity-gradient transect with comparable sites (inclination, location in the rain shadow of the coastal mountain range, 100 km distance between the sites) spanning roughly 600 km in the Atacama Desert for SOC stocks and SW content. We found, that SOC stocks decreased with aridity from 25.5 to 2.1 kg m-2 cm-1, while the SW contents decreased at 5 of our sites and increased in the hyper-arid zone. To our surprise, we identified two sites located 100 km north and south of Yungay which had substantially lower (1.92 ± 0.73 kg m-2 cm-1) or slightly higher (2.39 ± 1.2 kg m-2 cm-1) SOC stocks than Yungay (2.21 ± 0.75 kg m-2 cm-1), but with 0.043 ± 0.03 g respectively 0.0033 ± 0.0016 g of water per 1 g of soil comparable or substantially lower SW contents, while Yungay has 0.043 ± 0.06 g. Thus we consider these sites to display different growth conditions and ecological niches compared to Yungay and therefore as promising candidate sites for the identification of new species of polyextremophilic radiation-resistant microorganisms, as the resistance against desiccation is paired with a distinct resistance to ionizing radiation due to same microbial DNA repair mechanisms. Soil samples were irradiated with high doses of gamma radiation up to 25 000 Gy. Surviving colonies were cultivated on a medium favoring the growth of Deinococcus-like species, currently the most radiation-resistant organisms on Earth, and their affiliation was determined using 16SrRNA next generation sequencing. Here

  16. Effect of Fermented Supplementation on Growth Performance, Nutrient Digestibility, Blood Characteristics, Fecal Microbial and Fecal Noxious Gas Content in Growing Pigs

    Directory of Open Access Journals (Sweden)

    L. Yan

    2012-12-01

    Full Text Available A total of 96 growing pigs ((Landrace×Yorkshire×Duroc; BW = 26.58±1.41 kg were used in a 6-wk feeding trail to evaluate the effects of fermented chlorella (FC supplementation on growth performance, nutrient digestibility, blood characteristics, fecal microbial and fecal noxious gas content in growing pigs. Pigs were randomly allotted into 1 of 4 dietary treatments with 6 replicate pens (2 barrows and 2 gilts per treatment. Dietary treatments were: i negative control (NC, basal diet (without antibiotics; ii positive control (PC, NC+0.05% tylosin; iii (fermented chlorella 01 FC01, NC+0.1% FC, and iv fermented chlorella 02 (FC02, NC+0.2% FC. In this study, feeding pigs PC or FC01 diets led to a higher average daily gain (ADG and dry matter (DM digestibility than those fed NC diet (p0.05 was observed on the body weight, average daily feed intake (ADFI, gain:feed (G:F ratio, the apparent total tract digestibility of N and energy throughout the experiment. The inclusion of PC or FC did not affect the blood characteristics (p>0.05. Moreover, dietary FC treatment led to a higher (p<0.05 lactobacillus concentration and lower E. coli concentration than the NC treatment, whereas the antibiotic supplementation only decreased the E. coli concentration. Pigs fed FC or PC diet had reduced (p<0.05 fecal NH3 and H2S content compared with those fed NC diet. In conclusion, our results indicated that the inclusion of FC01 treatment could improve the growth performance, nutrient digestibility, fecal microbial shedding (lower E. coli and higher lactobacillus, and decrease the fecal noxious gas emission in growing pigs when compared with the group fed the basal diet. In conclusion, dietary FC could be considered as a good source of supplementation in growing pigs because of its growth promoting effect.

  17. Child weight growth trajectory and its determinants in a sample of Iranian children from birth until 2 years of age

    OpenAIRE

    Sayed-Mohsen Hosseini; Mohamad-Reza Maracy; Sheida Sarrafzade; Roya Kelishadi

    2014-01-01

    Background: Growth is one of the most important indices in child health. The best and most effective way to investigate child health is measuring the physical growth indices such as weight, height and head circumference. Among these measures, weight growth is the simplest and the most effective way to determine child growth status. Weight trend at a given age is the result of cumulative growth experience, whereas growth velocity represents what is happening at the time. Methods: This long...

  18. Ecosystem function in oil sands wetlands : rates of detrital decomposition, moss growth, and microbial respiration in oilsands wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Wytrykush, C. [Windsor Univ., ON (Canada); Hornung, J. [Petro-Canada, Calgary, AB (Canada)

    2007-07-01

    A study was conducted in which leaf litter breakdown and biomass accrual in 31 reference and oilsands affected (OSPM) wetlands in Northeastern Alberta was examined. The purpose was to determine how the decomposition of dead plant matter controls the primary productivity in wetlands. The data collected from this study will provide information about carbon flow and dynamics in oilsands affected wetlands. The study involved the investigation of wetlands that contrasted in water origin (OSPM vs. reference), sediment origin (OSPM vs. natural), sediment organic content and age. Mesh bags containing 5 g of dried Typha (cattail) or 20 g of damp moss were placed into 31 wetlands in order to monitor the rate at which biomass was lost to decomposition, as measured by changes in dry mass. After 1 year, moss growth was found to be greatest in younger wetlands with natural sediments. Cattail decomposition was found to be slower in wetlands containing OSPM water than that in reference wetlands. Preliminary analysis of respiration rates of biota associated with decomposing cattail indicate that the amount of oxygen consumed is not affected by wetland water source, sediment source, level of initial sediment organic content, or age.

  19. EFFECTS OF CAPITAL FLIGHT AND ITS MACROECONOMIC DETERMINANTS ON AGRICULTURAL GROWTH IN NIGERIA (1970-2013

    Directory of Open Access Journals (Sweden)

    Francis Robert Usman

    2014-10-01

    Full Text Available This study empirically examines the impact of capital fight and its macroeconomic determinants on agricultural growth in Nigeria from 1970 -2013. Data generated were analyzed using Unit root test, co-integration test, regression analysis. The study result found negative and insignificant relationship(P>0.05 between total capital flight and agricultural growth; meaning that capital flight has no direct impact on agricultural growth or the impact on agricultural growth is shadowed by the other macroeconomic variables in the system. Also, the stock of gross external debt (EXD variable showed positive and statistically significant relationship (P<0.05 with agricultural growth. The result shows that a unit change in EXD will bring about 24% change in the growth of agriculture provided other factors are kept constant. Political instability (POL variable has negative and significant effect on agricultural growth in Nigeria. The study recommends that Nigeria’s judicious use of the income accruing from loans and Foreign Direct Investment (FDI is paramount if Agricultural growth is to be enhanced. Furthermore, the overall peace, security of lives and property and guaranty of investment by the government is essential therefore; Government should take concerted step to improve security of life and property in the country.

  20. Impacts of biostimulant products on the growth of wheat and the microbial communities of its rhizosphere under contrasted production systems

    OpenAIRE

    Nguyen, Minh; Bodson, Bernard; Colinet, Gilles; Jijakli, Haissam; Ongena, Marc; Vandenbol, Micheline; du Jardin, Patrick; Spaepen, Stijn; Delaplace, Pierre

    2014-01-01

    Plant growth-promoting rhizobacteria (PGPR) are one of the major biostimulant classes due to their ability to stimulate root growth, enhance mineral availability, and nutrient use efficiency in crops. PGPR-containing biostimulant products could therefore make agriculture more sustainable by reducing demand for chemical fertilizer and lessen their negative environmental impacts. The aim of this project is to screen PGPR strains to (1) enhance wheat fitness level (growth, photosynthesis efficie...

  1. Effect of Acclimatization Time to Microbial Cell Growth and Biosynthesis of Mesophilic Gammaproteobacterium, in Orbital Shake Flasks

    Directory of Open Access Journals (Sweden)

    Azoddein Abd. Aziz Mohd

    2017-01-01

    Full Text Available Growth pattern of Pseudomonas putida (ATCC 49128, was found to predominantly rely on the age of the inoculums, prior to its contact with physical and chemical agents and nutrient availability. Under suitable inoculums, bacteria tend to grow faster in a batch type of growth pattern which is usually sustained until after nutrient depletion. In this research, the bacterial growth pattern was studied in an incubator shake flask using 8 g nutrient media and physical operational parameters temperature of 37oC and agitation of 180 rpm over a period of 24, 48 and 72 hours. Prior to this, P. putida was added into 20.0 ml nutrient broth and incubated in an incubator for 24 hours at 37oC, before adding it to 180 ml nutrient broth 30% (v/v1-. Growth, via acclimatization was initially observed after 1hr of inoculation with an overwhelming exponential growth of 2.69-2.57 within first 24 hr, exceeding the 48 and 72 hrs ranges. This additionally relates to particular cell biomass growth rate (μ of 0.58 hr1-, 3.87 number of generation (n, generation time (g 1.09 and growth rate constant (k of 0.01 hr1-, achievable within 24 hrs. It was therefore concluded that the sensitivity of this strain to time is significant, as optimal growth was achieved within 24 hrs of acclimatization, thereby showing a drastic reduction in the time of growth.

  2. Maternal body size and condition determine calf growth rates in southern right whales

    DEFF Research Database (Denmark)

    Christiansen, Fredrik; Vivier, Fabien; Charlton, Claire

    2018-01-01

    The cost of reproduction is a key parameter determining a species' life history strategy. Despite exhibiting some of the fastest offspring growth rates among mammals, the cost of reproduction in baleen whales is largely unknown since standard field metabolic techniques cannot be applied. We...... quantified the cost of reproduction for southern right whales Eubalaena australis over a 3 mo breeding season. We did this by determining the relationship between calf growth rate and maternal rate of loss in energy reserves, using repeated measurements of body volume obtained from unmanned aerial vehicle...... period, and highlights the importance of sufficient maternal energy reserves for reproduction in this capital breeding species....

  3. Effects of Biofertilizer Containing Microbial of N-fixer, P Solubilizer and Plant Growth Factor Producer on Cabbage (Brassica oleraceae var. Capitata Growth And Soil Enzymatic Activities: A Greenhouse Trial

    Directory of Open Access Journals (Sweden)

    Sarjiya Antonius

    2012-05-01

    Full Text Available The objective of this greenhouse study was to evaluate the effects of four different concentrations of biofertilizers containing Pseudomonas sp., Bacillus sp. and Streptomyces sp. on soil properties and to evaluate the growth of Brassica oleraceae var. capitata. The application treatments included control (no fertilizer and four concentration of diluted biofertilizer per pot (20 ml, 40 ml, 60 mland 80 ml. The application of biofertilizer containing benefi cial bacteria signifi cantly increased the growth of B. oleraceae. The useof biofertilizer resulted higher biomass weight and length as well as root length. This greenhouse study also indicated that differentamount of biofertilizer application had almost similar effects. Microbial inoculum not only increased plant harvest, but also improvedsoil properties, such as number of microorganisms, respiration and urease activities.

  4. How to determine control of growth rate in a chemostat. Using metabolic control analysis to resolve the paradox

    DEFF Research Database (Denmark)

    Snoep, Jacky L.; Jensen, Peter Ruhdal; Groeneveld, Philip

    1994-01-01

    how, paradoxically, one can determine control of growth rate, of growth yield and of other fluxes in a chemostat. We develop metabolic control analysis for the chemostat. this analysis does not depend on the particular way in which specific growth rate varies with the concentration of the growth...

  5. Work Tasks as Determinants of Grain Dust and Microbial Exposure in the Norwegian Grain and Compound Feed Industry

    NARCIS (Netherlands)

    Straumfors, Anne; Heldal, Kari Kulvik; Wouters, Inge M; Eduard, Wijnand

    OBJECTIVES: The grain and compound feed industry entails inevitable risks of exposure to grain dust and its microbial content. The objective of this study was therefore to investigate task-dependent exposure differences in order to create knowledge basis for awareness and exposure reducing measures

  6. Microbial Community Dynamics and Response to Plant Growth-Promoting Microorganisms in the Rhizosphere of Four Common Food Crops Cultivated in Hydroponics.

    Science.gov (United States)

    Sheridan, C; Depuydt, P; De Ro, M; Petit, C; Van Gysegem, E; Delaere, P; Dixon, M; Stasiak, M; Aciksöz, S B; Frossard, E; Paradiso, R; De Pascale, S; Ventorino, V; De Meyer, T; Sas, B; Geelen, D

    2017-02-01

    Plant growth promoting microorganisms (PGPMs) of the plant root zone microbiome have received limited attention in hydroponic cultivation systems. In the framework of a project aimed at the development of a biological life support system for manned missions in space, we investigated the effects of PGPMs on four common food crops (durum and bread wheat, potato and soybean) cultivated in recirculating hydroponic systems for a whole life cycle. Each crop was inoculated with a commercial PGPM mixture and the composition of the microbial communities associated with their root rhizosphere, rhizoplane/endosphere and with the recirculating nutrient solution was characterised through 16S- and ITS-targeted Illumina MiSeq sequencing. PGPM addition was shown to induce changes in the composition of these communities, though these changes varied both between crops and over time. Microbial communities of PGPM-treated plants were shown to be more stable over time. Though additional development is required, this study highlights the potential benefits that PGPMs may confer to plants grown in hydroponic systems, particularly when cultivated in extreme environments such as space.

  7. Determinants of regional labour productivity growth: A study for the hospitality sector in Spain

    Directory of Open Access Journals (Sweden)

    Bienvenido Ortega Aguaza

    2013-01-01

    Full Text Available The aim of this paper is to analyze the determinants of labour productivity growth in the hospitality industry in Spain using regional data over the period 1996-2004. The results obtained suggest that the increase in the number of 3-star hotels and the reduction process in the stock of physical capital per worker are factors which may have contributed to the fall in productivity growth. However, increased regional tourism intensity has a positive impact on the growth of labour productivity. Nonetheless, changes in demand-related factors, such as average length of stay and the seasonality of demand, have not had a significant aggregate impact on labour productivity growth during this period.

  8. Determinants of infant growth in Eastern Uganda: a community-based cross-sectional study.

    Science.gov (United States)

    Engebretsen, Ingunn Marie Stadskleiv; Tylleskär, Thorkild; Wamani, Henry; Karamagi, Charles; Tumwine, James K

    2008-12-22

    Child under-nutrition is a leading factor underlying child mortality and morbidity in Sub-Saharan Africa. Several studies from Uganda have reported impaired growth, but there have been few if any community-based infant anthropometric studies from Eastern Uganda. The aim of this study was to describe current infant growth patterns using WHO Child Growth Standards and to determine the extent to which these patterns are associated with infant feeding practices, equity dimensions, morbidity and use of primary health care for the infants. A cross-sectional survey of infant feeding practices, socio-economic characteristics and anthropometric measurements was conducted in Mbale District, Eastern Uganda in 2003; 723 mother-infant (0-11 months) pairs were analysed. Infant anthropometric status was assessed using z-scores for weight-for-length (WLZ), length-for-age (LAZ) and weight-for-age (WAZ). Dependent dichotomous variables were constructed using WLZ growth among Ugandan infants.

  9. The Effects of Biochar and Its Combination with Compost on Lettuce (Lactuca sativa L. Growth, Soil Properties, and Soil Microbial Activity and Abundance

    Directory of Open Access Journals (Sweden)

    Dalila Trupiano

    2017-01-01

    Full Text Available Impacts of biochar application in combination with organic fertilizer, such as compost, are not fully understood. In this study, we tested the effects of biochar amendment, compost addition, and their combination on lettuce plants grown in a soil poor in nutrients; soil microbiological, chemical, and physical characteristics were analyzed, together with plant growth and physiology. An initial screening was also done to evaluate the effect of biochar and compost toxicity, using cress plants and earthworms. Results showed that compost amendment had clear and positive effects on plant growth and yield and on soil chemical characteristics. However, we demonstrated that also the biochar alone stimulated lettuce leaves number and total biomass, improving soil total nitrogen and phosphorus contents, as well as total carbon, and enhancing related microbial communities. Nevertheless, combining biochar and compost, no positive synergic and summative effects were observed. Our results thus demonstrate that in a soil poor in nutrients the biochar alone could be effectively used to enhance soil fertility and plant growth and biomass yield. However, we can speculate that the combination of compost and biochar may enhance and sustain soil biophysical and chemical characteristics and improve crop productivity over time.

  10. The effects of different levels of Beta Plus on growth performance, microbial flora and blood parameters of Caspian trout, Salmo caspius (Kessler, 1877

    Directory of Open Access Journals (Sweden)

    Sadegh Krimzadeh

    2014-11-01

    Full Text Available This study was conducted to evaluate the effects of Beta plus probiotic, a mixture of Bacillius leicheniformic and Bacillius subtilis, on the growth performance and intestinal microbial flora of Caspian trout (Salmo caspius. A basal diet was formulated and supplemented with Beta plus at 0, 0.5 and 1 g kg-1, leading to three experimental diets. Each experimental diet was randomly assigned to quadruple 1500 L tanks. The Caspian trout with an initial weight of 108.7 ± 1.8 g were randomly distributed in the experimental tanks. The results showed that inclusion of dietary Beta plus significantly increased the final weight and specific growth rate (SGR of Caspian trout compared to those the control treatment. The feed conversion ratio (FCR was also improved significantly after probiotic administration to the experimental fish. However, the body composition and blood parameters were not influenced by the probiotic inclusion. Total count of Gram positive and negative bacteria in the intestine of the fish increased by feeding on diet contained 1 g kg-1 Beta Plus (P<0.05. In conclusion, administration of the probiotic Beta plus can improve the nutrient efficiency and growth performance of Caspian trout confirming the positive effect of a mixture of Bacillus spp.

  11. Radiographically determined growth kinetics of primary lung tumors in the dog

    International Nuclear Information System (INIS)

    Perry, R.E.; Weller, R.E.; Buschbom, R.L.; Dagle, G.E.; Park, J.F.

    1989-10-01

    Tumor growth rate patterns especially tumor doubling time (TDT), have been extensively evaluated in man. Studies involving the determination of TDT in humans are limited, however, by the number of cases, time consistent radiographic tumor measurements, and inability to perform experimental procedures. In animals similar constraints do not exist. Lifespan animal models lend themselves well to tumor growth pattern analysis. Experimental studies have been designed to evaluate both the biological effects and growth patterns of induced and spontaneous tumors. The purpose of this study was to calculate the tumor volume doubling times (TCDT) for radiation-induced and spontaneous primary pulmonary neoplasms in dogs to see if differences existed due to etiology, sex or histologic cell type, and to determine if the time of tumor onset could be extrapolated from the TVDT. 3 refs

  12. Radioimmunological determination of insulin, growth hormone and calcitonin in serum, ch. 2

    International Nuclear Information System (INIS)

    Froelich, M.

    1977-01-01

    Radioimmunoassay procedures for the determination of insulin, growth hormone and calcitonin in blood serum were developed. The procedure as well as the iodination of antigens and the generation of antibodies are described. Short-term and long-term quality control experiments dealing with specificity, recovery, sensitivity, intrassay variability and interassay variability are reported

  13. Using Growth Curves To Determine the Timing of the Booster Sessions.

    Science.gov (United States)

    Hennessy, Michael; Bolan, Gail A.; Hoxworth, Tamara; Iatesta, Michael; Rhodes, Fen; Zenilman, Jonathan M.

    1999-01-01

    Demonstrates an application of a method for using growth curves to determine the timing of booster sessions to reinforce the cognitive messages or behavior changes of interventions. Uses data from a multisite randomized experiment that compared three counseling and testing methods for preventing sexual disease transmission. Presents…

  14. Determination of free insulin-like growth factor-I in human serum

    DEFF Research Database (Denmark)

    Frystyk, J.; Skjærbæk, C.; Ivarsen, P.

    2001-01-01

    Two fundamentally different methods are currently used for the determination of free insulin-like growth factor-I (IGF-I): ultrafiltration by centrifugation (UF) and direct immunoradiometric assay (IRMA). The aim was to evaluate a commercial IRMA (DSL, Webster, TX, USA) and to compare it with UF....

  15. Determination of the shell growth direction during the formation of silica microcapsules by confocal fluorescence microscopy

    NARCIS (Netherlands)

    van Wijk, J.; Salari, J.W.O.; Meuldijk, J.; Klumperman, L.

    2015-01-01

    A novel procedure was developed to determine the direction of silica growth during the formation of a silica shell around aqueous microdroplets in water-in-oil Pickering emulsions. Two fluorescently labeled silica precursors were added consecutively and the resulting microcapsules were visualized

  16. Effects of concentrate replacement by feed blocks on ruminal fermentation and microbial growth in goats and single-flow continuous-culture fermenters.

    Science.gov (United States)

    Molina-Alcaide, E; Pascual, M R; Cantalapiedra-Hijar, G; Morales-García, E Y; Martín-García, A I

    2009-04-01

    The effect of replacing concentrate with 2 different feed blocks (FB) on ruminal fermentation and microbial growth was evaluated in goats and in single-flow continuous-culture fermenters. Diets consisted of alfalfa hay plus concentrate and alfalfa hay plus concentrate with 1 of the 2 studied FB. Three trials were carried out with 6 rumen-fistulated Granadina goats and 3 incubation runs in 6 single-flow continuous-culture fermenters. Experimental treatments were assigned randomly within each run, with 2 repetitions for each diet. At the end of each in vivo trial, the rumen contents were obtained for inoculating the fermenters. For each incubation run, the fermenters were inoculated with ruminal fluid from goats fed the same diet supplied to the corresponding fermenter flask. The average pH values, total and individual VFA, and NH(3)-N concentrations, and acetate:propionate ratios in the rumen of goats were not affected (P >or= 0.10) by diet, whereas the microbial N flow (MNF) and efficiency were affected (P fermenters, the diet affected pH (Por= 0.05), and total (P=0.02), NH(3) (P=0.005), and non-NH(3) (P=0.02) N flows, whereas the efficiency of VFA production was not affected (P=0.75). The effect of diet on MNF and efficiency depended on the bacterial pellet used as a reference. An effect (Pfermenter contents and effluent were similar (P=0.05). Differences (Pfermentation variables and bacterial pellet compositions were found. Partial replacement of the concentrate with FB did not greatly compromise carbohydrate fermentation in unproductive goats. However, this was not the case for MNF and efficiency. Differences between the results obtained in vivo and in vitro indicate a need to identify conditions in fermenters that allow better simulation of fermentation, microbial growth, and bacterial pellet composition in vivo. Reduced feeding cost could be achieved with the inclusion of FB in the diets of unproductive goats without altering rumen fermentation.

  17. Effect of a microbial phytase on growth performance, plasma parameters and apparent ileal amino acid digestibility in Youxian Sheldrake fed a low-phosphorus corn-soybean diet

    Directory of Open Access Journals (Sweden)

    Shaoping He

    2017-10-01

    Full Text Available Objective This study investigated the effect of microbial phytase supplementation on growth performance, tibia ash, plasma parameters, apparent ileal digestibility (AID of amino acid (AA and apparent digestibility of nutrients in Youxian Sheldrakes fed with low-phosphorus (P corn-soybean diets. Methods A total of 350 Youxian Sheldrakes (7d old were randomly divided into 5 treatment groups: positive control (PC group has adequate available P diet (0.42% and 0.38%, starter and grower, negative control (NC group were deficient in available P (0.32% and 0.28%, starter and grower and NC diet was supplemented with 3 levels of microbial phytase (500, 750, and 1,000 U/kg. Results Dietary supplementation of phytase in NC diet improved the average daily gain, increased the levels of serum calcium (Ca, tibia Ca and P, AID of AA and apparent digestibility of energy and Ca in starter stage (p<0.05. There was an increased (p<0.001 in the utilization of P from 17.3% to 23.9%. Phytase supplementation (1,000 U/kg has shown that the AID of His, Thr, Val, indispensable AA, Glu, Pro, and dispensable AA was higher (p<0.05 than that of NC. Moreover, phytase supplementation improved (p<0.05 serum and tibia Ca and P, AID of AA and apparent digestibility of dry matter, crude protein, energy, P and Ca, and reduced (p<0.05 feed to gain ratio (F/G and the levels of serum alkaline phosphatase in grower stage. Likewise, an increase (p<0.001 in the utilization of P was noticed from 12.6% to 17.2%. Supplement phytase at 750 U/kg improved the AID of His, Thr, Asp, Cys, Pro, and Ser (p<0.05. Conclusion The microbial phytase supplement could improve growth performance, AID of some AA and apparent utilization of other nutrients in Youxian Sheldrakes, and reduce excreta P load to environment.

  18. Timescales of Growth Response of Microbial Mats to Environmental Change in an Ice-Covered Antarctic Lake

    Directory of Open Access Journals (Sweden)

    Anne D. Jungblut

    2013-01-01

    Full Text Available Lake Vanda is a perennially ice-covered, closed-basin lake in the McMurdo Dry Valleys, Antarctica. Laminated photosynthetic microbial mats cover the floor of the lake from below the ice cover to >40 m depth. In recent decades, the water level of Lake Vanda has been rising, creating a “natural experiment” on development of mat communities on newly flooded substrates and the response of deeper mats to declining irradiance. Mats in recently flooded depths accumulate one lamina (~0.3 mm per year and accrue ~0.18 µg chlorophyll-a cm−2 y−1. As they increase in thickness, vertical zonation becomes evident, with the upper 2-4 laminae forming an orange-brown zone, rich in myxoxanthophyll and dominated by intertwined Leptolyngbya trichomes. Below this, up to six phycobilin-rich green/pink-pigmented laminae form a subsurface zone, inhabited by Leptolyngbya, Oscillatoria and Phormidium morphotypes. Laminae continued to increase in thickness for several years after burial, and PAM fluorometry indicated photosynthetic potential in all pigmented laminae. At depths that have been submerged for >40 years, mats showed similar internal zonation and formed complex pinnacle structures that were only beginning to appear in shallower mats. Chlorophyll-a did not change over time and these mats appear to represent resource-limited “climax” communities. Acclimation of microbial mats to changing environmental conditions is a slow process, and our data show how legacy effects of past change persist into the modern community structure.

  19. Effects of X-ray irradiation on the microbial growth and quality of flue-cured tobacco during aging

    International Nuclear Information System (INIS)

    Wang, J.J.; Xu, Z.C.; Fan, J.L.; Wang, Y.; Tian, Z.J.; Chen, Y.T.

    2015-01-01

    X-ray irradiation was evaluated for improving microbial safety and the quality of flue-cured tobacco during aging. Tobacco samples were irradiated at doses of 0, 1, 2, 3 and 5 kGy and stored for 12 months under normal storage conditions or in a high-humidity (RH>70%) room. Microbiological data indicated that the population of total aerobic bacteria was significantly decreased with increasing irradiation doses. In particular, a dose of 2 kGy was effective for the decontamination of fungi from the tested samples, with a 0.93 log CFU/g reduction for bacteria. The control and 1 kGy X-ray treated tobacco samples were became rotted and moldy after the 12th month, whereas those treated with 2, 3 and 5 kGy had no detectable mold during 12 months of storage at high humidity. Chemical measurements showed that irradiation up to 3 kGy did not affect the total nitrogen, nicotine, reducing and total sugars, ratio of total nitrogen to nicotine and sugar-to-nicotine ratio. Furthermore, sensory evaluation results also showed that X-ray irradiation did not affect sensory scores with irradiation at a dose <3 kGy. Based on these results, X-ray irradiation dose in the range of 2–3 kGy is recommended for the decontamination of fungi from flue-cured tobacco. - Highlights: • 2 kGy dose improved sufficiently the microbial safety of flue-cured tobacco. • The doses up to 3 kGy did not affect the chemical components. • A dose <3 kGy had no effect on sensory scores. • The recommended dose to irradiated flue-cured tobacco is the range of 2–3 kGy

  20. Determination of the growth of nematophagous fungi on diverse carbon sources

    Directory of Open Access Journals (Sweden)

    Martha Orozco

    2015-11-01

    Full Text Available Organic amendments have been widely used to stimulate the populations of predatory nematophagous fungi (PNF in soil; however, the use of organic amendments has produced inconsistent results in the control of parasitic nematodes. The inconsistencies have been partially attributed to the chemical composition of the organic amendments, specifically to carbon and nitrogen contents. Therefore, to know the carbon preferences of these fungi could be helpful to promote the predatory phase of the PNF in soil. The aim of this study was to determine the growth of native PNF strains from Costa Rica in diverse carbon sources. The PNF Arthrobotrys oligospora and Candelabrella musiformis were grown in artificial culture media containing the following carbon sources: cellulose, chitin, pectin, starch, and skim milk. The growth rate developed by the PNF in each one of the culture media was determined and compared. The growth rates developed by both fungal species followed the next order: cellulos e>chitin>pectin>starch>skim milk. Significant differences in the growth rates developed by the fungal strains were detected only in culture medium containing cellulose, in comparison with culture media containing other carbon sources. In culture medium containing cellulose both A. oligospora and C. musiformis grew faster with respect to the other culture media, but A. oligospora strains grew faster in comparison with C. musiformis strains. Both fungal species developed the lowest growth rates in culture media containing starch and skim milk.

  1. Interactive optical trapping shows that confinement is a determinant of growth in a mixed yeast culture

    DEFF Research Database (Denmark)

    Arneborg, N.; Siegumfeldt, H.; Andersen, G.H.

    2005-01-01

    Applying a newly developed user-interactive optical trapping system, we controllably surrounded individual cells of one yeast species, Hanseniaspora uvarum, with viable cells of another yeast species, Saccharomyces cerevisiae, thus creating a confinement of the former. Growth of surrounded and non......-surrounded H. uvarum cells was followed under a microscope by determining their generation time. The average generation time of surrounded H. uvarum cells was 15% higher than that of non-surrounded cells thereby showing that the confinement imposed by viable S. cerevisiae cells on H. uvarum inhibits growth...

  2. Genotype, soil type, and locale effects on reciprocal transplant vigor, endophyte growth, and microbial functional diversity of a narrow sagebrush hybrid zone in Salt Creek Canyon, Utah

    Science.gov (United States)

    Miglia, K.J.; McArthur, E.D.; Redman, R.S.; Rodriguez, R.J.; Zak, J.C.; Freeman, D.C.

    2007-01-01

    When addressing the nature of ecological adaptation and environmental factors limiting population ranges and contributing to speciation, it is important to consider not only the plant's genotype and its response to the environment, but also any close interactions that it has with other organisms, specifically, symbiotic microorganisms. To investigate this, soils and seedlings were reciprocally transplanted into common gardens of the big sagebrush hybrid zone in Salt Creek Canyon, Utah, to determine location and edaphic effects on the fitness of parental and hybrid plants. Endophytic symbionts and functional microbial diversity of indigenous and transplanted soils and sagebrush plants were also examined. Strong selection occurred against the parental genotypes in the middle hybrid zone garden in middle hybrid zone soil; F1 hybrids had the highest fitness under these conditions. Neither of the parental genotypes had superior fitness in their indigenous soils and habitats; rather F1 hybrids with the nonindigenous maternal parent were superiorly fit. Significant garden-by-soil type interactions indicate adaptation of both plant and soil microorganisms to their indigenous soils and habitats, most notably in the middle hybrid zone garden in middle hybrid zone soil. Contrasting performances of F1 hybrids suggest asymmetrical gene flow with mountain, rather than basin, big sagebrush acting as the maternal parent. We showed that the microbial community impacted the performance of parental and hybrid plants in different soils, likely limiting the ranges of the different genotypes.

  3. Birth order dependent growth cone segregation determines synaptic layer identity in the Drosophila visual system.

    Science.gov (United States)

    Kulkarni, Abhishek; Ertekin, Deniz; Lee, Chi-Hon; Hummel, Thomas

    2016-03-17

    The precise recognition of appropriate synaptic partner neurons is a critical step during neural circuit assembly. However, little is known about the developmental context in which recognition specificity is important to establish synaptic contacts. We show that in the Drosophila visual system, sequential segregation of photoreceptor afferents, reflecting their birth order, lead to differential positioning of their growth cones in the early target region. By combining loss- and gain-of-function analyses we demonstrate that relative differences in the expression of the transcription factor Sequoia regulate R cell growth cone segregation. This initial growth cone positioning is consolidated via cell-adhesion molecule Capricious in R8 axons. Further, we show that the initial growth cone positioning determines synaptic layer selection through proximity-based axon-target interactions. Taken together, we demonstrate that birth order dependent pre-patterning of afferent growth cones is an essential pre-requisite for the identification of synaptic partner neurons during visual map formation in Drosophila.

  4. Improved microbial growth inhibition activity of bio-surfactant induced Ag–TiO{sub 2} core shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nithyadevi, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Kumar, P. Suresh [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Ponpandian, N.; Viswanathan, C. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Meena, P. [Department of Physics, PSGR Krishnammal college for women, Coimbatore 641 004 (India)

    2015-02-01

    Graphical abstract: - Highlights: • TiO{sub 2} nanoparticles were synthesized by hydrolysis process and Ag nanoparticles were prepared by using hydrazine reduction method. • Ag–TiO{sub 2} core shell nanoparticles were synthesized by reverse micelle method. • Coatings of TiO{sub 2} shell leads to decrease the usage of silver particles and also it reduces the release of silver ions from the matrix. • Optimum ratio of TiO{sub 2} particles: Ag atoms are needed for better antibacterial activity. • Sodium alginate (Bio-copolymer) induced core shell nanoparticles results 100% cell growth inhibition toward Staphylococcus aureus. - Abstract: Surfactant induced silver–titanium dioxide core shell nanoparticles within the size range of 10–50 nm were applied in the antibacterial agent to inhibit the growth of bacterial cells. The single crystalline silver was located in the core part of the composite powder and the titanium dioxide components were uniformly distributed in the shell part. HRTEM and XRD results indicated that silver was completely covered by titanium dioxide and its crystal structure was not affected after being coated by titanium dioxide. The effect of silver–titanium dioxide nanoparticles in the inhibition of bacterial cell growth was studied by means of disk diffusion method. The inhibition zone results reveal that sodium alginate induced silver–titanium dioxide nanoparticles exhibit 100% more antibacterial activity than that with cetyltrimethylbromide or without surfactant. UV–vis spectroscopic analysis showed a large concentration of silver was rapidly released into phosphate buffer solution (PBS) within a period of 1 day, with a much smaller concentration being released after this 1-day period. It was concluded that sodium alginate induced silver–titanium dioxide core shell nanoparticles could enhance long term cell growth inhibition in comparison with cetyltrimethylbromide or without surfactant. The surfactant mediated core shell

  5. Crystal structure of the tyrosine kinase domain of the hepatocyte growth factor receptor c-Met and its complex with the microbial alkaloid K-252a.

    Science.gov (United States)

    Schiering, Nikolaus; Knapp, Stefan; Marconi, Marina; Flocco, Maria M; Cui, Jean; Perego, Rita; Rusconi, Luisa; Cristiani, Cinzia

    2003-10-28

    The protooncogene c-met codes for the hepatocyte growth factor receptor tyrosine kinase. Binding of its ligand, hepatocyte growth factor/scatter factor, stimulates receptor autophosphorylation, which leads to pleiotropic downstream signaling events in epithelial cells, including cell growth, motility, and invasion. These events are mediated by interaction of cytoplasmic effectors, generally through Src homology 2 (SH2) domains, with two phosphotyrosine-containing sequence motifs in the unique C-terminal tail of c-Met (supersite). There is a strong link between aberrant c-Met activity and oncogenesis, which makes this kinase an important cancer drug target. The furanosylated indolocarbazole K-252a belongs to a family of microbial alkaloids that also includes staurosporine. It was recently shown to be a potent inhibitor of c-Met. Here we report the crystal structures of an unphosphorylated c-Met kinase domain harboring a human cancer mutation and its complex with K-252a at 1.8-A resolution. The structure follows the well established architecture of protein kinases. It adopts a unique, inhibitory conformation of the activation loop, a catalytically noncompetent orientation of helix alphaC, and reveals the complete C-terminal docking site. The first SH2-binding motif (1349YVHV) adopts an extended conformation, whereas the second motif (1356YVNV), a binding site for Grb2-SH2, folds as a type II Beta-turn. The intermediate portion of the supersite (1353NATY) assumes a type I Beta-turn conformation as in an Shc-phosphotyrosine binding domain peptide complex. K-252a is bound in the adenosine pocket with an analogous binding mode to those observed in previously reported structures of protein kinases in complex with staurosporine.

  6. Carbon use efficiency (CUE) and biomass turnover of soil microbial communities as affected by bedrock, land management and soil temperature and moisture

    Science.gov (United States)

    Zheng, Qing; Hu, Yuntao; Richter, Andreas; Wanek, Wolfgang

    2017-04-01

    Soil microbial carbon use efficiency (CUE), defined as the proportion of organic C taken up that is allocated to microbial growth, represents an important synthetic representation of microbial community C metabolism that describes the flux partitioning between microbial respiration and growth. Therefore, studying microbial CUE is critical for the understanding of soil C cycling. Microbial CUE is thought to vary with environmental conditions (e.g. temperature and soil moisture). Microbial CUE is thought to decrease with increasing temperature and declining soil moisture, as the latter may trigger stress responses (e.g. the synthesis of stress metabolites), which may consequently lower microbial community CUE. However, these effects on microbial CUE have not been adequately measured so far due to methodological restrictions. The most widely used methods for microbial CUE estimation are based on tracing 13C-labeled substrates into microbial biomass and respiratory CO2, approaches that are known to overestimate microbial CUE of native organic matter in soil. Recently, a novel substrate-independent approach based on the measurement of (i) respiration rates and (ii) the incorporation rates of 18O from labelled water into newly formed microbial DNA has been developed in our laboratory for measuring microbial CUE. This approach overcomes the shortcomings of previously used methods and has already been shown to yield realistic estimations of soil microbial CUE. This approach can also be applied to concurrently measure microbial biomass turnover rates, which also influence the sequestration of soil organic C. Microbial turnover rates are also thought to be impacted by environmental factors, but rarely have been directly measured so far. Here, we aimed at determining the short-term effects of environmental factors (soil temperature and soil moisture) on microbial CUE and microbial biomass turnover rates based on the novel 18O approach. Soils from three land-use types (arable

  7. 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

  8. Growth

    Science.gov (United States)

    John R. Jones; George A. Schier

    1985-01-01

    This chapter considers aspen growth as a process, and discusses some characteristics of the growth and development of trees and stands. For the most part, factors affecting growth are discussed elsewhere, particularly in the GENETICS AND VARIATION chapter and in chapters in PART 11. ECOLOGY. Aspen growth as it relates to wood production is examined in the WOOD RESOURCE...

  9. Microbial diversity in hydrothermal surface to subsurface environments of Suiyo Seamount, Izu-Bonin Arc, using a catheter-type in situ growth chamber.

    Science.gov (United States)

    Higashi, Yowsuke; Sunamura, Michinari; Kitamura, Keiko; Nakamura, Ko-ichi; Kurusu, Yasurou; Ishibashi, Jun-ichiro; Urabe, Tetsuro; Maruyama, Akihiko

    2004-03-01

    After excavation using a portable submarine driller near deep-sea hydrothermal vents in the Suiyo Seamount, Izu-Bonin Arc, microbial diversity was examined in samples collected from inside the boreholes using an in situ growth chamber called a vent catheter. This instrument, which we devised for this study, consists of a heat-tolerant pipe tipped with a titanium mesh entrapment capsule that is packed with sterilized inorganic porous grains, which serve as an adhesion substrate. After this instrument was deployed inside each of the boreholes, as well as a natural vent, for 3-10 days in the vicinity of hot vent fluids (maxima: 156-305 degrees C), DNA was extracted from the adhesion grains, 16S rDNA was amplified, and randomly selected clones were sequenced. In phylogenetic analysis of more than 120 clones, several novel phylotypes were detected within the epsilon-Proteobacteria, photosynthetic bacteria (PSB)-related alpha-Proteobacteria, and Euryarchaeota clusters. Members of epsilon-Proteobacteria were frequently encountered. Half of these were classified between two known groups, Corre's B and D. The other half of the clones were assigned to new groups, SSSV-BE1 and SSSV-BE2 (Suiyo Seamount sub-vent origin, Bacteria domain, epsilon-Proteobacteria, groups 1 and 2). From this hydrothermal vent field, we detected a novel lineage within the PSB cluster, SSNV-BA1 (Suiyo Seamount natural vent origin, Bacteria domain, alpha-Proteobacteria, group 1), which is closely related to Rhodopila globiformis isolated from a hot spring. A number of archaeal clones were also detected from the borehole samples. These clones formed a novel monophyletic clade, SSSV-AE1 (Suiyo Seamount sub-vent origin, Archaea domain, Euryarchaeota, group 1), approximately between methanogenic hyperthermophilic members of Methanococcales and environmental clone members of DHVE Group II. Thus, this hydrothermal vent environment appears to be a noteworthy microbial and genetic resource. It is also

  10. Microbial assisted phyto extraction of metals and growth of soybean (glycine max l. merrill) on industrial waste water contaminated soil

    International Nuclear Information System (INIS)

    Ali, I.; Bano, A.

    2012-01-01

    Pots experiments were made to investigate the role of effective microorganisms (EM) in improving phyto extraction of metals (Cd/sup +2/ and Mn/sup +2/) and growth of soybean plant in industrial waste water polluted soil. Waste water applications to soil were made in four different dilutions (i.e. 25%, 50%, 75% and 100%). Effective microorganisms were added into waste water prior to application. Effect of treatments on growth parameters was studied. The Cd/sup +2/ and Mn/sup +2/ concentrations in different parts of plant were measured by Atomic Absorption Spectrophotometer. Plant height significantly increased at all treatments except at 25% waste water treatment. Plant dry biomass and oil contents in seed significantly increased with all treatments compared to control but were higher at low concentration of waste water. Waste water treatments significantly increased the Cd and Mn accumulation in plant while inoculation of EM further enhanced the metals accumulation. The maximum accumulation of Cd and Mn found in plant treated with 100% waste water in combination with effective microorganisms. At harvest, the Cd/sup +2/ concentration decreased in leaves but increased in roots followed by stem > seeds, while, Mn/sup +2/ accumulation increased in leaves followed by roots > stem > seeds. Conclusively, EM enhanced the phyto extraction of Cd and Mn and also increased the oil contents in soybean on polluted soil. These findings suggest further investigation to find out a suitable concentration of industrial waste water in combination with EM for better growth of soybean and improving phyto extraction of metals. (author)

  11. Spatiotemporal Dynamics and Spatial Determinants of Urban Growth in Suzhou, China

    Directory of Open Access Journals (Sweden)

    Ling Zhang

    2017-03-01

    Full Text Available This paper analyzes the spatiotemporal dynamics of urban growth and models its spatial determinants in China through a case study of Suzhou, a rapidly industrializing and globalizing city. We conducted spatial analysis on land use data derived from multi-temporal remote sensing images of Suzhou from 1986 to 2008. Three urban growth types, namely infilling, edge-expansion, and leapfrog, were identified. We used landscape metrics to quantify the temporal trend of urban growth in Suzhou. During these 22 years, Suzhou’s urbanization changed from bottom-up rural urbanization to city-based top-down urban expansion. The underlying mechanism changed from TVE (town village enterprise driven rural industrialization to FDI (foreign direct investment driven development zone fever. Furthermore, we employed both global and local logistic regressions to model the probability of urban land conversion against a set of spatial variables. The global logistic regression model found the significance of proximity, neighborhood conditions, and socioeconomic factors. The logistic geographically weighted regression (GWR model improved the global regression model with better model goodness-of-fit and higher prediction accuracy. More importantly, the local parameter estimates of variables enabled us to exam spatial variations of the influences of variables on urban growth in Suzhou.

  12. Socio-Economic Convergence as a Necessary Precondition and Determinant of Societal Growth

    Directory of Open Access Journals (Sweden)

    Hudec Martin

    2016-12-01

    Full Text Available The issue of socio-economic convergence is nowadays more than ever an extremely dominant topic, especially in the case of less developed countries and countries suffering stagnation, mainly due to the integration processes occurring worldwide and the determinant to achieve long-term growth in an effort to advance towards the socioeconomic sustainable level of developed economies. A key assumption towards convergence is that economies with initially lower socio-economic levels will at some point reach (in an idea case or get very close the level of developed economies, gradually reducing the gap between the capital stock and the level of product size between countries, while the lower economic level the country has, the higher the growth rate it will go through the transition period. This suggests that the economies with lower levels of performance will grow on average at a higher rate than economies that are more efficient. It is therefore expected that the growth performance of a country will with its improvement also at some point slow down and quite realistically there can also occur a situation where the levels of development and growth of individual states economies will rather show delay. This is basically an opposite action to the concept of convergence, which is known as the divergence. The aim of our research paper is to analyze closely the concept of convergence, while pointing it is specifically characteristics and overall focusing on the significance of the issue of convergence.

  13. Determination of human pathogen profiles in food by quality assured microbial assays. Proceedings of a final Research Coordination Meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-01-15

    This publication includes the results of a Coordinated Research Project (CRP). Major food microbial contaminants were identified in some of the main foods exported in the international food market. Thousands of samples in a wide variety of foods were selected to be studied during different points of the food chain: meat (chicken, beef and pork), seafood (shellfish such as shrimp, prawns, scampi, squid, and lobsters, and different types of fish such as salmon, cuttle fish, rohu, fin herring, catfish, milkfish, and tilapia), spices (pepper, paprika), frozen vegetables (asparagus, peas and corn) and other products (coconut and dairy products). The analysis included pathogenic bacteria such as Salmonella spp. (several serotypes), Escherichia coli, E. coli 0157:H7, Staphylococcus aureus, Clostridium perfringens, Bacillus cereus, Vibrio choleare, Vibrio parahaemolitycus and Yersinia enterolítica. This publication includes data that may be used to conduct better risk assessments on food by importing as well as exporting countries.

  14. A rapid method for the determination of microbial susceptibility using the firefly luciferase assay for adenosine triphosphate (ATP)

    Science.gov (United States)

    Vellend, H.; Tuttle, S. A.; Barza, M.; Weinstein, L.; Picciolo, G. L.; Chappelle, E. W.

    1975-01-01

    Luciferase assay for adenosine triphosphate (ATP) was optimized for pure bacteria in broth in order to evaluate if changes in bacterial ATP content could be used as a rapid measure of antibiotic effect on microorganisms. Broth cultures of log phase bacteria were incubated at 310 K (37 C) for 2.5 hours at antimicrobial concentrations which resulted in the best discrimination between sensitive and resistant strains. Eighty-seven strains of 11 bacterial species were studied for their susceptibility to 12 commonly used antimicrobial agents: ampicillin, Penicillin G, nafcillin, carbenicillin, cephalothin, tetracycline, erythromycin, clindamycin, gentamicin, nitrofurantoin, colistin, and chloramplenicol. The major advantage of the ATP system over existing methods of rapid microbial susceptibility testing is that the assay can be made specific for bacterial ATP.

  15. Determination of optimized growth medium and cryoprotective additives to enhance the growth and survival of Lactobacillus salivarius.

    Science.gov (United States)

    Yeo, Soyoung; Shin, Hee Sung; Lee, Hye Won; Hong, Doseon; Park, Hyunjoon; Holzapfel, Wilhelm; Kim, Eun Bae; Huh, Chul Sung

    2018-03-16

    Beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, i.e., to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius , and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, 0.2 g MgSO 4 ∙7H 2 O, 0.02 g MnSO 4 ∙H 2 O, 1 g K 2 HPO 4 , 1.5 g KH 2 PO 4 , 0.01 g FeSO 4 ∙7H 2 O and 1 g sodium citrate. A cryoprotective additive combination comprising 10% ( w/v ) skim milk and 10% ( w/v ) sucrose supplemented with 2.5% ( w/v ) sodium glutamate was selected for L. salivarius , and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius . On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.

  16. The impact and determinants of the energy paradigm on economic growth in European Union.

    Science.gov (United States)

    Andrei, Jean Vasile; Mieila, Mihai; Panait, Mirela

    2017-01-01

    Contemporary economies are strongly reliant on energy and analyzing the determining factors that trigger the changes in energy paradigm and their impact upon economic growth is a topical research subject. Our contention is that energy paradigm plays a major role in achieving the sustainable development of contemporary economies. In order to prove this the panel data methodology of research was employed, namely four panel unit root tests (LLC, IPS, F-ADF and F-PP) aiming to reveal the connections and relevance among 17 variables denoting energy influence on economic development. Moreover, it was introduced a specific indicator to express energy consumption per capita. Our findings extend the classical approach of the changes in energy paradigm and their impact upon economic growth and offer a comprehensive analysis which surpasses the practices and policy decisions in the field.

  17. Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis

    Science.gov (United States)

    Macavoy, S. E.; Jamil, T.; Macko, S. A.; Arneson, L. S.

    2003-12-01

    Stable isotope analysis is becoming an extensively used tool in animal ecology. The isotopes most commonly used for analysis in terrestrial systems are those of carbon and nitrogen, due to differential carbon fractionation in C3 and C4 plants, and the approximately 3‰ enrichment in 15N per trophic level. Although isotope signatures in animal tissues presumably reflect the local food web, analysis is often complicated by differential nutrient routing and fractionation by tissues, and by the possibility that large organisms are not in isotopic equilibrium with the foods available in their immediate environment. Additionally, the rate at which organisms incorporate the isotope signature of a food through both growth and metabolic tissue replacement is largely unknown. In this study we have assessed the rate of carbon and nitrogen isotopic turnover in liver, muscle and blood in mice following a diet change. By determining growth rates, we were able to determine the proportion of tissue turnover caused by growth versus that caused by metabolic tissue replacement. Growth was found to account for approximately 10% of observed tissue turnover in sexually mature mice (Mus musculus). Blood carbon was found to have the shortest half-life (16.9 days), followed by muscle (24.7 days). Liver carbon turnover was not as well described by the exponential decay equations as other tissues. However, substantial liver carbon turnover was observed by the 28th day after diet switch. Surprisingly, these tissues primarily reflect the carbon signature of the protein, rather than carbohydrate, source in their diet. The nitrogen signature in all tissues was enriched by 3 - 5‰ over their dietary protein source, depending on tissue type, and the isotopic turnover rates were comparable to those observed in carbon.

  18. Characterisation of microbial biocoenosis in vertical subsurface flow constructed wetlands

    International Nuclear Information System (INIS)

    Tietz, Alexandra; Kirschner, Alexander; Langergraber, Guenter; Sleytr, Kirsten; Haberl, Raimund

    2007-01-01

    In this study a quantitative description of the microbial biocoenosis in subsurface vertical flow constructed wetlands fed with municipal wastewater was carried out. Three different methods (substrate induced respiration, ATP measurement and fumigation-extraction) were applied to measure the microbial biomass at different depths of planted and unplanted systems. Additionally, bacterial biomass was determined by epifluorescence microscopy and productivity was measured via 14 C leucine incorporation into bacterial biomass. All methods showed that > 50% of microbial biomass and bacterial activity could be found in the first cm and about 95% in the first 10 cm of the filter layer. Bacterial biomass in the first 10 cm of the filter body accounted only for 16-19% of the total microbial biomass. Whether fungi or methodical uncertainties are mainly responsible for the difference between microbial and bacterial biomass remains to be examined. A comparison between the purification performance of planted and unplanted pilot-scale subsurface vertical flow constructed wetlands (PSCWs) showed no significant difference with the exception of the reduction of enterococci. The microbial biomass in all depths of the filter body was also not different in planted and unplanted systems. Compared with data from soils the microbial biomass in the PSCWs was high, although the specific surface area of the used sandy filter material available for biofilm growth was lower, especially in the beginning of the set-up of the PSCWs, due to missing clay and silt fraction

  19. Dead Pericarps of Dry Fruits Function as Long-Term Storage for Active Hydrolytic Enzymes and Other Substances That Affect Germination and Microbial Growth

    Directory of Open Access Journals (Sweden)

    James Godwin

    2017-12-01

    Full Text Available It is commonly assumed that dead pericarps of dry indehiscent fruits have evolved to provide an additional physical layer for embryo protection and as a means for long distance dispersal. The pericarps of dry fruits undergo programmed cell death (PCD during maturation whereby most macromolecules such DNA, RNA, and proteins are thought to be degraded and their constituents remobilized to filial tissues such as embryo and endosperm. We wanted to test the hypothesis that the dead pericarp represents an elaborated layer that is capable of storing active proteins and other substances for increasing survival rate of germinating seeds. Using in gel assays we found that dead pericarps of both dehiscent and indehiscent dry fruits of various plant species including Arabidopsis thaliana and Sinapis alba release upon hydration multiple active hydrolytic enzymes that can persist in an active form for decades, including nucleases, proteases, and chitinases. Proteomic analysis of indehiscent pericarp of S. alba revealed multiple proteins released upon hydration, among them proteases and chitinases, as well as proteins involved in reactive oxygen species (ROS detoxification and cell wall modification. Pericarps appear to function also as a nutritional element-rich storage for nitrate, potassium, phosphorus, sulfur, and others. Sinapis alba dehiscent and indehiscent pericarps possess germination inhibitory substances as well as substances that promote microbial growth. Collectively, our study explored previously unknown features of the dead pericarp acting also as a reservoir of biological active proteins, and other substances capable of “engineering” the microenvironment for the benefit of the embryo.

  20. Colonial vs planktonic type of growth: mathematical modeling of microbial dynamics on surfaces and in liquid, semi-liquid and solid foods

    Directory of Open Access Journals (Sweden)

    Panagiotis N. Skandamis

    2015-10-01

    Full Text Available Predictive models are mathematical expressions that describe the growth, survival, inactivation or biochemical processes of foodborne bacteria. During processing of contaminated raw materials and food preparation, bacteria are entrapped into the food residues, potentially transferred to the equipment surfaces (abiotic or inert surfaces or cross-contaminate other foods (biotic surfaces. Growth of bacterial cells can either occur planktonically in liquid or immobilized as colonies. Colonies are on the surface or confined in the interior (submerged colonies of structured foods. For low initial levels of bacterial population leading to large colonies, the immobilized growth differs from planktonic growth due to physical constrains and to diffusion limitations within the structured foods. Indeed, cells in colonies experience substrate starvation and/or stresses from the accumulation of toxic metabolites such as lactic acid. Furthermore, the micro-architecture of foods also influences the rate and extent of growth. The micro-architecture is determined by (i the non-aqueous phase with the distribution and size of oil particles and the pore size of the network when proteins or gelling agent are solidified, and by (ii the available aqueous phase within which bacteria may swarm or swim. As a consequence, the micro-environment of bacterial cells when they grow in colonies might greatly differs from that when they grow planktonically. The broth-based data used for modeling (lag time and generation time, the growth rate and population level are poorly transferable to solid foods. It may lead to an over-estimation or under-estimation of the predicted population compared to the observed population in food. If the growth prediction concerns pathogen bacteria, it is a major importance for the safety of foods to improve the knowledge on immobilized growth. In this review, the different types of models are presented taking into account the stochastic behavior of

  1. Radiation-induced sprout and growth inhibition in vegetables with special reference to the susceptibility to microbial attacks and the effect of calcium

    International Nuclear Information System (INIS)

    Skou, J.P.

    1979-03-01

    Experiments have shown ionizing irradiation to be an effective method for sprout and growth inhibition but it is necessary to keep the doses at the absolute minimum in order to avoid unwanted by-effects One of the by-effects is an increased susceptibility to storage rot in potatoes, onions and carrots. This effect is connected with the wounding and bruising caused by digging up and handling as the wound healing process is inhibited simultaneously with the sprout inhibition. Patogens increase tissue permeability during pathogenesis and, as irradiation has an analogous effect on tissues it might facilitate the growth of the pathogens. Irradiation softens the tissue and mobilizes the calcium in the tissue; this may thereby make the tissue more accessible to microbial attack. An external supply of calcium increases the firmness of tissue, reduces tissue permeability, and may compensate for the loss of calcium in irradiated tissue mainly as a result of a surplus of calcium in the wounds. Botrytis cinerea and Sclerotinia sclerotiorum were some of the most wide spread and serious pathogens in carrots, which vegetable were the main object of the studies. Culture filtrates of these fungi had a strong macerating activity on carrot tissues. The effect, which results from activity and interaction of pectolytic enzymes and oxalic acid, could be reduced or nullified by calcium. A diversity of the groups of pectolytic enzymes are widely distributed among organisms and not confined to plant pathogens. Because of this, because there exists pectolytic enzymes for every condition and pectic substances, and because calcium is not very inhibiting to all kinds of pectolytic enzymes it is not to be expected that the protective effect of calcium will always be expressed to the same extent on storage of the products. (author)

  2. Impact of lyophilized Lactobacillus salivarius DSPV 001P administration on growth performance, microbial translocation, and gastrointestinal microbiota of broilers reared under low ambient temperature.

    Science.gov (United States)

    Blajman, J E; Olivero, C A; Fusari, M L; Zimmermann, J A; Rossler, E; Berisvil, A P; Romero Scharpen, A; Astesana, D M; Soto, L P; Signorini, M L; Zbrun, M V; Frizzo, L S

    2017-10-01

    This study was undertaken with the aim of investigating the effects of dietary supplementation of probiotic strain Lactobacillus salivarius DSPV 001P on growth performance, microbial translocation, and gastrointestinal microbiota of broilers reared under low ambient temperature. Two hundred and forty, one-day-old male Cobb broilers were randomly distributed into two treatment groups, a probiotic group and a control group, with four replicates per treatment and 30 broilers per replicate. The temperature of the broiler house was maintained at 18-22°C during the first three weeks, after which the temperature was at range of 8°C to 12°C. The results showed that probiotic treatment significantly improved body weight of broilers when compared with the control group. After 42days, the weight means were 2905±365.4g and 2724±427.0g, respectively. Although there were no significant differences, dietary inclusion of L. salivarius tended to increase feed intake and to reduce feed conversion ratio during the six-week experimental period. Similarly, supplementation tended to reduce the rate of mortality, with 12 deaths occurring in the probiotic group, and 20 in the control group. However, no differences were observed in intestinal bacterial concentrations of Enterobacteriaceae, E.coli, and lactic acid bacteria in both crop and caecum among treatments. Through our study, it appears that L. salivarius DSPV 001P was non-pathogenic, safe and beneficial to broilers, which implies that it could be a promising feed additive, thus enhancing the growth performance of broilers and improving their health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Colonial vs. planktonic type of growth: mathematical modeling of microbial dynamics on surfaces and in liquid, semi-liquid and solid foods.

    Science.gov (United States)

    Skandamis, Panagiotis N; Jeanson, Sophie

    2015-01-01

    Predictive models are mathematical expressions that describe the growth, survival, inactivation, or biochemical processes of foodborne bacteria. During processing of contaminated raw materials and food preparation, bacteria are entrapped into the food residues, potentially transferred to the equipment surfaces (abiotic or inert surfaces) or cross-contaminate other foods (biotic surfaces). Growth of bacterial cells can either occur planktonically in liquid or immobilized as colonies. Colonies are on the surface or confined in the interior (submerged colonies) of structured foods. For low initial levels of bacterial population leading to large colonies, the immobilized growth differs from planktonic growth due to physical constrains and to diffusion limitations within the structured foods. Indeed, cells in colonies experience substrate starvation and/or stresses from the accumulation of toxic metabolites such as lactic acid. Furthermore, the micro-architecture of foods also influences the rate and extent of growth. The micro-architecture is determined by (i) the non-aqueous phase with the distribution and size of oil particles and the pore size of the network when proteins or gelling agent are solidified, and by (ii) the available aqueous phase within which bacteria may swarm or swim. As a consequence, the micro-environment of bacterial cells when they grow in colonies might greatly differs from that when they grow planktonically. The broth-based data used for modeling (lag time and generation time, the growth rate, and population level) are poorly transferable to solid foods. It may lead to an over-estimation or under-estimation of the predicted population compared to the observed population in food. If the growth prediction concerns pathogen bacteria, it is a major importance for the safety of foods to improve the knowledge on immobilized growth. In this review, the different types of models are presented taking into account the stochastic behavior of single cells

  4. Nuclear techniques to determine microbial protein synthesis and productive performance of barki lambs fed rations containing some medicinal plants

    International Nuclear Information System (INIS)

    Mohamed, M.M.S.

    2009-01-01

    This study included two experiments, the first experiment was carried out in vitro to evaluate the effect of adding two levels of Lemongrass or Rosemary in ruminant rations on microbial protein synthesis using radio active sulfur S 35 . While, the second experiment was to study the effect of Lemongrass (CC) and Rosemary (RO) as feed additives in rations of lambs on feed intake, nutrient digestibility, some parameters of blood and rumen activity. Meanwhile, body weight and economical efficiency were studied. Twenty five of Barki male lambs with average body weight of 19.8 kg ± 1 kg and 3- 4 months of age were divided into 5 similar groups (5 lambs each). The first group (control) (R1) was fed on a concentrate feed mixture (CFM) plus rice straw (RS). While, R2 and R3 were fed as R1 ration supplemented with 100 or 200 mg Lemongrass /kg LBW/d respectively. Meantime, R4 and R5 were fed as R1 ration supplemented with 100 or 200 mg Rosemary /kg LBW/d respectively.The results indicated that more microbial protein synthesis was noticed with 4 mg of Lemongrass followed by 2 mg Rosemary, 2 mg Lemongrass and control which was higher than 4 mg Rosemary/ 0.5 g concentrate mixture. The differences were not statistically significant. The dry matter intake (DMI) was not significantly different for R4 and R3 when compared with R1 (control) and it significantly decreased in R5 and R2 compared with R1. The digestibilities of DM, OM, CP, EE and NFE in the supplemented groups were not significantly differing compared with R1. The digestibility of CF was significantly increased in R2 and R4 compared with R1 and there were no significant differences for R3 and R5 compared with R1. There were no significant differences in nutritive values as TDN, DCP and SV among all supplemented groups compared with R1. Rumen liquor TVFA,s was not significantly differ at zero time, but it decreased at 3 h and 6 h with all additives compared with the control with no significant differences among all

  5. Determination of Microbial Nitrogen Production by Using Urinary Allantoin and Blood Metabolite Concentrate in Growing Brahman Cattle Fed the Different Proportion of Roughage and Concentrate in Diets

    International Nuclear Information System (INIS)

    Suthikrai, Wanvipa; Usawang, Sungwon; Kijsamrej, Suriya; Sophon, Sunpetch; Jetana, Thongsuk

    2003-06-01

    Determination of microbial nitrogen synthesis by using urinary allantoin and blood metabolite for evaluating the efficiency of feed utilization, in this study was conducted by using four Brahman bulls (about 1 year old). Animals were fed ad libitum with 4 fixed diets of four combinations of pineapple fibre (P) and concentrate (C) in the proportions, on dry matter basis of 0.8:0.2 (P80:C20), 0.6:0.04(P60:C40), 0.4:0.6(P40:C60) and 0.2:0.8 (P20:C80). The experiment was designed as a 4x4 Latin square design The Results showed that increasing in the proportion of concentrate linearly increased the rumen microbial nitrogen production (p<0.001), the concentrations of Insulin and urea-N in plasma and the concentration of urea-N in the urine, but not affected on the concentrations of glucose and creatinine in plasma. In conclusion, the using of allantoin urinary associated with blood metabolite can evaluate the accuracy in evaluation of feed utilization in Brahman cattle

  6. Application of 13C-labeling and 13C-13C COSY NMR experiments in the structure determination of a microbial natural product.

    Science.gov (United States)

    Kwon, Yun; Park, Sunghyouk; Shin, Jongheon; Oh, Dong-Chan

    2014-08-01

    The elucidation of the structures of complex natural products bearing many quaternary carbons remains challenging, even in this advanced spectroscopic era. (13)C-(13)C COSY NMR spectroscopy shows direct couplings between (13)C and (13)C, which comprise the backbone of a natural product. Thus, this type of experiment is particularly useful for natural products bearing consecutive quaternary carbons. However, the low sensitivity of (13)C-based NMR experiments, due to the low natural abundance of the (13)C nucleus, is problematic when applying these techniques. Our efforts in the (13)C labeling of a microbial natural product, cyclopiazonic acid (1), by feeding (13)C-labeled glucose to the fungal culture, enabled us to acquire (13)C-(13)C COSY NMR spectra on a milligram scale that clearly show the carbon backbone of the compound. This is the first application of (13)C-(13)C COSY NMR experiments for a natural product. The results suggest that (13)C-(13)C COSY NMR spectroscopy can be routinely used for the structure determination of microbial natural products by (13)C-enrichment of a compound with (13)C-glucose.

  7. What Determines the Growth Ambition of Dutch Early-Stage Entrepreneurs?

    OpenAIRE

    Ingrid Verheul; Linda van Mil

    2008-01-01

    This paper investigates the determinants of the ambition to grow among Dutch early-stage entrepreneurs (nascents and young business owners). We use Adult Population Survey data of the Global Entrepreneurship Monitor (GEM) for the Netherlands. Merging cross-sectional data of the years 2002 to 2007, we arrive at a sample of 409 nascents and 336 young business owners. Growth ambition is measured by asking the respondent which statement fits him or her best: (1) I want my company to be as large a...

  8. The Growth Determinant in the Industrial Sector Featured in East Java Province

    Directory of Open Access Journals (Sweden)

    Mohtar Rasyid

    2016-06-01

    Full Text Available This article aims toanalyzethe main determining factorof growthof industrialsector, especiallythe small scale industriesin East Javaover the past decade. Using theofthe Cobb-Douglas production functionapproach, this research assessedinputfactorconsisting oflabor, capitalandrawmaterials.This study used apooling regression modelto estimate the coefficient of production function fromfourgroups ofselected industries namely:the food industry, textile industry, wood industryandpaperindustry. The results showedthat the sourceof growthfor the industryisstilldominatedbythe physicalgrowth ofinputandnot byproductivity growth. As a result, in the long rungrowth ofthe industry is difficulttobesustainable and relativelyvulnerable toeconomic shocks. Based onthese findingssuggested thatpolicy makersfocus more onefforts toimprove the quality ofinputs, in particularinputqualityhuman resourcesor labor.  

  9. Vermicomposting of herbal pharmaceutical industry waste: earthworm growth, plant-available nutrient and microbial quality of end materials.

    Science.gov (United States)

    Singh, Deepika; Suthar, Surindra

    2012-05-01

    Efforts were made to decompose herbal pharmaceutical industrial waste (HPIW) spiked with cow dung (CD) using Eisenia fetida. A total of five vermibeds: T(1) - HPIW (0%+CD 100%, control), T(2) - HPIW (25%), T(3) - HPIW (50%), T(4) - HPIW (75%) and T(5) - HPIW (100%) were used for vermicomposting. The changes in biology and chemistry of vermibeds were measured after ten days interval. E. fetida showed high growth and cocoon production rate in all vermibeds. The vermicomposted material contained great population of fungi 6.0-40.6 (CFU × 10(5)g(-1)), bacteria 220-1276.0 (CFU × 10(8)g(-1)) and actinomycetes 410.0-2962.0 (CFU × 10(5)g(-1)) than initial material. Vermicomposted material was rich in plant-available forms of nutrients (N-NO(3)(-),PO(4)(3-),available K and SO(4)(-2)). Results suggested that noxious industrial waste can be converted into valuable product for sustainable soil fertility programme. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Changes in root-associated microbial communities are determined by species-specific plant growth responses to stress and disturbance

    Czech Academy of Sciences Publication Activity Database

    Bouasria, A.; Mustafa, T.; de Bello, Francesco; Zinger, L.; Lemperiere, G.; Geremia, R. A.; Choler, P.

    2012-01-01

    Roč. 52, Sep-Oct 2012 (2012), s. 59-66 ISSN 1164-5563 Institutional support: RVO:67985939 Keywords : ecosystem function * bacterial communities * grassland communities Subject RIV: EF - Botanics Impact factor: 1.838, year: 2012

  11. Short communication: Effects of increasing protein and energy in the milk replacer with or without direct-fed microbial supplementation on growth and performance of preweaned Holstein calves.

    Science.gov (United States)

    Geiger, A J; Ward, S H; Williams, C C; Rude, B J; Cabrera, C J; Kalestch, K N; Voelz, B E

    2014-11-01

    Forty-four Holstein calves were fed a direct-fed microbial (DFM) and 1 of 2 milk replacers to evaluate calf performance and growth. Treatments were (1) a control milk replacer [22:20; 22% crude protein (CP) and 20% fat], (2) an accelerated milk replacer (27:10; 27% CP and 10% fat), (3) the control milk replacer with added DFM (22:20+D), and (4) the accelerated milk replacer with added DFM (27:10+D). Dry matter intake, rectal temperatures, respiration scores and rates, and fecal scores were collected daily. Body weight, hip and withers height, heart girth, blood, and rumen fluid samples were collected weekly. Effects of treatment, sex, week, and their interactions were analyzed. Calves fed an accelerated milk replacer, regardless of DFM supplementation, consumed more CP and metabolizable energy in the milk replacer. No treatment differences were found for starter intake or intake of neutral detergent fiber or acid detergent fiber in the starter. Calves fed the accelerated milk replacer had greater preweaning and weaning body weight compared with calves fed the control milk replacer. Average daily gain was greater during the preweaning period for calves fed the accelerated milk replacer, but the same pattern did not hold true during the postweaning period. Feed efficiency did not differ among treatments. Hip height tended to be and withers height and heart girth were greater at weaning for calves fed the accelerated milk replacer compared with calves fed the control milk replacer. Fecal scores were greatest in calves fed DFM. Overall acetate, propionate, butyrate, and n-valerate concentrations were lower in calves fed the accelerated milk replacer, but DFM did not have an effect. Rumen pH was not different. Blood metabolites were unaffected by DFM supplementation, but calves fed the accelerated milk replacer had increased partial pressure of CO2, bicarbonate, and total bicarbonate in the blood. Direct-fed microbial supplementation did not appear to benefit the calf

  12. Determination of Sintered (Th,U)O2 Pellet at the Grain Growth Step

    International Nuclear Information System (INIS)

    Indrati-Y, Tundjung; Pristi-Hartati, Murdani; Ari-Handayani; Ginting, Aslina Br

    2000-01-01

    The determination of sintered (Th,U)O 2 pellet at the grain growth stephave been done by dilatometer and Scanning Electron Microscope (SEM). Thecalculation method based on the densification curve and quantitativemetallurgy. The green pellet be produced by single action compaction. Itspellet was heated on the dilatometer with heating rate 11 o C/minute and inthe argon atmosphere, 2 liters/hour. The activation energy at thedensification step can be calculated by densification curve only, but theactivation energy at the grain growth step can be calculated by densificationcurve or quantitative metallurgy. The capability of the dilatometer can beoperated until 1200 o C, so the densification curve based on the experiencecan be used to calculate activation energy at the densification step, 4.492kcal/mole. The activation energy at the grain growth step, which is 25.277kcal/mole, can be predicted by trial and error on n value. That activationenergy is almost the same with activation energy that based on thequantitative metallurgy method 25.042 kcal/mole. All of the activation energyfor the (Th,U)O 2 pellet sintering process is 29.769 kcal/mole. (author)

  13. A Review of Microbially Induced Corrosion (MIC) of Steel and a Preliminary Investigation to Determine Its Occurrence in Naval Vessels

    Science.gov (United States)

    1993-05-01

    decimal dilution; i.e. 1 l0 Il], aSepticalvY transterred to ’) 0 inl1 dilutinig fluid and shaken and the procedure repeated .2 .2 Sw~ ab Samples...Materials Research Laboratory. Videla, H.A. (1985). The action of Cladosporium resinae growth on the electrochemical behaviour of aluminium. In Biologically

  14. Effect of dietary supplementation with Rhizopus oryzae or Chrysonilia crassa on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

    OpenAIRE

    S. Sugiharto; T. Yudiarti; I. Isroli; E. Widiastuti; F. D. Putra

    2017-01-01

    Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS) on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from...

  15. Determinate growth in Pisum: 'det' a new mutant gene on chromosome 7

    International Nuclear Information System (INIS)

    Swiecicki, W.K.

    1988-01-01

    Full text: A characteristic feature of the growth of legume plants is the absence of a clear border between vegetative and generative phase. By contrast in cereals, the growth of the vegetative mass ceases with flowering and assimilates are destined for filling grains. With regard to this feature in breeding of legume crops the ideotype of 'the self-completion variety' has been conceived. In the broad sense, this term means a plant with a clear end of vegetative growth, after which assimilates should be transported to seeds resulting in more uniform maturity and higher seed yield. Such self-completion can be achieved in different ways, even in the same species. In white lupin, e.g. the cultivar 'Wat' drops its leaves in the stage of pod filling. Moreover, in white lupin as well as in yellow and narrow-leaved lupins unbranched genotypes have been selected in which only one, the main stem develops with the inflorescence on top. Additional nodes with a single flower appear instead of branches. The field bean Vicia faba similar to the pea produces inflorescence on nodes and consecutive nodes develop continuously from the apical meristem. But in the mutation type 'determinate growth', controlled by a single gene, the stem is ended by the inflorescence. A comparable gene was found in pea in 1980 as an effect of seed treatment of the line Wt 3527 by the combined dose 200r Nf+0.014% NEU. Plants are characterized by inflorescence on the top of the stem and smaller number of flowering nodes. Sometimes apical flowers are abnormal, open, but fertile. The mutant was included in the gene bank under number Wt 16100. A phenotypically similar line was found at the John Innes Institute, Norwich (UK). According to the locus allelism test (Wt 16100 x Jl 1358) both mutants are controlled by the same gene. The suggested symbol for this monogenic inherited character is det determinated growth. For the linkage test, the tester line Wl 1238 was crossed with the mutant Wt 16100. The

  16. Determinate growth in Pisum: 'det' a new mutant gene on chromosome 7

    Energy Technology Data Exchange (ETDEWEB)

    Swiecicki, W K [Plant Breeding Station, Wiatrowo (Poland)

    1988-07-01

    Full text: A characteristic feature of the growth of legume plants is the absence of a clear border between vegetative and generative phase. By contrast in cereals, the growth of the vegetative mass ceases with flowering and assimilates are destined for filling grains. With regard to this feature in breeding of legume crops the ideotype of 'the self-completion variety' has been conceived. In the broad sense, this term means a plant with a clear end of vegetative growth, after which assimilates should be transported to seeds resulting in more uniform maturity and higher seed yield. Such self-completion can be achieved in different ways, even in the same species. In white lupin, e.g. the cultivar 'Wat' drops its leaves in the stage of pod filling. Moreover, in white lupin as well as in yellow and narrow-leaved lupins unbranched genotypes have been selected in which only one, the main stem develops with the inflorescence on top. Additional nodes with a single flower appear instead of branches. The field bean Vicia faba similar to the pea produces inflorescence on nodes and consecutive nodes develop continuously from the apical meristem. But in the mutation type 'determinate growth', controlled by a single gene, the stem is ended by the inflorescence. A comparable gene was found in pea in 1980 as an effect of seed treatment of the line Wt 3527 by the combined dose 200r Nf+0.014% NEU. Plants are characterized by inflorescence on the top of the stem and smaller number of flowering nodes. Sometimes apical flowers are abnormal, open, but fertile. The mutant was included in the gene bank under number Wt 16100. A phenotypically similar line was found at the John Innes Institute, Norwich (UK). According to the locus allelism test (Wt 16100 x Jl 1358) both mutants are controlled by the same gene. The suggested symbol for this monogenic inherited character is det determinated growth. For the linkage test, the tester line Wl 1238 was crossed with the mutant Wt 16100. The

  17. In Situ Determination of Thermal Profiles during Czochralski Silicon Crystal Growth by an Eddy Current Technique.

    Science.gov (United States)

    Choe, Kwang Su.

    An eddy current testing method was developed to continuously monitor crystal growth process and determine thermal profiles in situ during Czochralski silicon crystal growth. The work was motivated by the need to improve the quality of the crystal by controlling thermal gradients and annealing history over the growth cycle. The experimental concept is to monitor intrinsic electrical conductivities of the growing crystal and deduce temperature values from them. The experiments were performed in a resistance-heated Czochralski puller with a 203 mm (8 inch) diameter crucible containing 6.5 kg melt. The silicon crystals being grown were about 80 mm in diameter and monitored by an encircling sensor operating at three different test frequencies (86, 53 and 19 kHz). A one-dimensional analytical solution was employed to translate the detected signals into electrical conductivities. In terms of experiments, the effects of changes in growth condition, which is defined by crystal and crucible rotation rates, crucible position, pull rate, and hot-zone configuration, were investigated. Under a given steady-state condition, the thermal profile was usually stable over the entire length of crystal growth. The profile shifted significantly, however, when the crucible rotation rate was kept too high. As a direct evidence to the effects of melt flow on heat transfer process, a thermal gradient minimum was observed about the crystal/crucible rotation combination of 20/-10 rpm cw. The thermal gradient reduction was still most pronounced when the pull rate or the radiant heat loss to the environment was decreased: a nearly flat axial thermal gradient was achieved when either the pull rate was halved or the height of the exposed crucible wall was effectively doubled. Under these conditions, the average axial thermal gradient along the surface of the crystal was about 4-5 ^{rm o}C/mm. Regardless of growth condition, the three-frequency data revealed radial thermal gradients much larger

  18. Assessment of the microbial growth potential of slow sand filtrate with the biomass production potential test in comparison with the assimilable organic carbon method.

    Science.gov (United States)

    van der Kooij, Dick; Veenendaal, Harm R; van der Mark, Ed J; Dignum, Marco

    2017-11-15

    Slow sand filtration is the final treatment step at four surface-water supplies in the Netherlands. The microbial growth potential (MGP) of the finished water was measured with the assimilable organic carbon (AOC) method using pure cultures and the biomass production potential (BPP) test. In the BPP test, water samples were incubated untreated at 25 °C and the active-biomass concentration was measured by adenosine tri-phosphate (ATP) analysis. Addition of a river-water inoculum improved the test performance and characteristic growth and maintenance profiles of the water were obtained. The maximum ATP concentration attained within seven days and the cumulative biomass production after 14 days of incubation (BPC 14 , d ng ATP L -1 ) showed highly significant and strong linear relationships with the AOC in the slow sand filtrates. The lowest AOC and BPC 14 levels were observed in the supplies applying dune filtration without ozonation in post treatment, with AOC/TOC = 1.7 ± 0.3 μg acetate-C equivalents mg -1 C and BPC 14 /TOC = 16.3 ± 2.2 d ng ATP mg -1 C, corresponding with 1.2 ± 0.19 ng ATP mg -1 C. These characteristics may represent the lowest specific MGP of natural organic matter achievable by biofiltration at temperatures ≤20 °C. The AOC and BPC 14 concentrations in the slow sand filtrate of the supply treating lake water by ozonation with granular-activated-carbon filtration and slow sand filtration as post treatment increased with decreasing temperature. The BPP test revealed that this slow sand filtrate sampled at 2 °C contained growth-promoting compounds that were not detected with the AOC test. These observations demonstrate the utility of the BPP test for assessing the MGP of drinking water and show the performance limits of biofiltration for MGP reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Determination of water-soluble vitamins using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts.

    Science.gov (United States)

    Tsukatani, Tadayuki; Suenaga, Hikaru; Ishiyama, Munetaka; Ezoe, Takatoshi; Matsumoto, Kiyoshi

    2011-07-15

    A method for the determination of water-soluble vitamins using a colorimetric microbial viability assay based on the reduction of the tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt (WST-8)} via 2-methyl-1,4-napthoquinone (NQ) was developed. Measurement conditions were optimized for the microbiological determination of water-soluble vitamins, such as vitamin B(6), biotin, folic acid, niacin, and pantothenic acid, using microorganisms that have a water-soluble vitamin requirement. A linear relationship between absorbance and water-soluble vitamin concentration was obtained. The proposed method was applied to determine the concentration of vitamin B(6) in various foodstuffs. There was good agreement between vitamin B(6) concentrations determined after 24h using the WST-8 colorimetric method and those obtained after 48h using a conventional method. The results suggest that the WST-8 colorimetric assay is a useful method for the rapid determination of water-soluble vitamins in a 96-well microtiter plate. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Radioimmunological determination of somatomedin B in healthy children and in children with growth disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, S.; Schoenberger, W.; Roth, A.; Grimm, W. (Children' s Hospital and Department of Clinical Radiologie, Johannes Gutenberg-Universitaet Mainz, FRG)

    1983-01-01

    Serum somatomedin B levels were determined by radioimmunoassay in 209 healthy boys and girls from one month to 16 years of age. Low values were found up to the second year life. In the first year the mean level was 13.8 mg/l in girls and 11.5 mg/l in boys. In older children the values increased to levels between 13 and 22 mg/l in boys and between 13 and 18.5 mg/l in girls. They were independent of the stage of pubertal development. Somatomedin B levels were normal in 71 children with constitutional growth delay, primordial dwarfism, familial dwarfism and other forms of growth disturbance. The mean levels were between 12.1 and 14.4 mg/l. Values below 6 mg/l were present only in children with hGH deficiency. In these patients we could find an increase of the mean level from 4.3 mg/l without therapy to 9.4 mg/l under treatment. Thus the determination of somatomedin B seems to be useful for the diagnosis of hGH deficiency.

  1. Radioimmunological determination of somatomedin B in healthy children and in children with growth disturbances

    International Nuclear Information System (INIS)

    Wirth, S.; Schoenberger, W.; Roth, A.; Grimm, W.

    1983-01-01

    Serum somatomedin B levels were determined by radioimmunoassay in 209 helthy boys and girls from one month to 16 years of age. Low values were found up to the second year life. In the first year the mean level was 13.8 mg/l in girls and 11.5 mg/l in boys. In older children the values increased to levels between 13 and 22 mg/l in boys and between 13 and 18.5 mg/l in girls. They were independent of the stage of pubertal development. Somatomedin B levels were normal in 71 children with constitutional growth delay, primordial dwarfism, familial dwarfism and other forms of growth disturbance. The mean levels were between 12.1 and 14.4 mg/l. Values below 6 mg/l were present only in children with hGH deficiency. In these patients we could find an increase of the mean level from 4.3 mg/l without therapy to 9.4 mg/l under treatment. Thus the determination of somatomedin B seems to be useful for the diagnosis of hGH deficiency. (author)

  2. Microbial cultures in open globe injuries in southern India.

    Science.gov (United States)

    Gupta, Arvind; Srinivasan, Renuka; Kaliaperumal, Subashini; Setia, Sajita

    2007-07-01

    To determine the risk factors leading to positive intraocular culture in patients with open globe injury. A prospective interventional study involving 110 eyes of 110 patients of more than 15 years of age, presenting with open globe injury, was undertaken. Emergency repair of the injured globe was done. Prolapsed intraocular tissue or aqueous humour was sent for microbial work up before repair. In endophthalmitis cases intravitreal antibiotics were given according to the antimicrobial sensitivity. Chi-square and logistic regression analysis were used to determine the risk factors. Fifty-six patients showed microbial contamination. Bacteria were cultured in 42 patients and fungi in 14 patients. Nineteen patients developed endophthalmitis, of which 18 patients showed microbial growth initially. In univariate analysis, initial visual acuity (8 mm, P 72 h, P 8 mm, P = 0.013) were associated with increased risk of positive microbial culture. Six patients had intraocular foreign body but were culture negative. Age, gender, site of injury and presence of cataract did not significantly affect the culture positivity. Microbial contamination is a risk factor for the development for endophthalmitis. Despite the high frequency of microbial contamination, it develops only in few cases. Systemic antibiotics, virulence of the organism and host factors play a role in the manifestation of endophthalmitis. Prophylaxis with intraocular antibiotics should be strongly considered in cases with poor vision at presentation, larger corneoscleral laceration, delayed surgical intervention and uveal tissue or vitreous prolapse.

  3. Regeneration of roots from callus reveals stability of the developmental program for determinate root growth in Sonoran Desert Cactaceae.

    Science.gov (United States)

    Shishkova, Svetlana; García-Mendoza, Edith; Castillo-Díaz, Vicente; Moreno, Norma E; Arellano, Jesús; Dubrovsky, Joseph G

    2007-05-01

    In some Sonoran Desert Cactaceae the primary root has a determinate root growth: the cells of the root apical meristem undergo only a few cell division cycles and then differentiate. The determinate growth of primary roots in Cactaceae was found in plants cultivated under various growth conditions, and could not be reverted by any treatment tested. The mechanisms involved in root meristem maintenance and determinate root growth in plants remain poorly understood. In this study, we have shown that roots regenerated from the callus of two Cactaceae species, Stenocereus gummosus and Ferocactus peninsulae, have a determinate growth pattern, similar to that of the primary root. To demonstrate this, a protocol for root regeneration from callus was established. The determinate growth pattern of roots regenerated from callus suggests that the program of root development is very stable in these species. These findings will permit future analysis of the role of certain Cactaceae genes in the determinate pattern of root growth via the regeneration of transgenic roots from transformed calli.

  4. Use of static Quantitative Microbial Risk Assessment to determine pathogen risks in an unconfined carbonate aquifer used for Managed Aquifer Recharge.

    Science.gov (United States)

    Toze, Simon; Bekele, Elise; Page, Declan; Sidhu, Jatinder; Shackleton, Mark

    2010-02-01

    Managed Aquifer Recharge (MAR) is becoming a mechanism used for recycling treated wastewater and captured urban stormwater and is being used as a treatment barrier to remove contaminants such as pathogens from the recharged water. There is still a need, however, to demonstrate the effectiveness of MAR to reduce any residual risk of pathogens in the recovered water. A MAR research site recharging secondary treated wastewater in an unconfined carbonate aquifer was used in conjunction with a static Quantitative Microbial Risk Assessment (QMRA) to assess the microbial pathogen risk in the recovered water following infiltration and aquifer passage. The research involved undertaking a detailed hydrogeological assessment of the aquifer at the MAR site and determining the decay rates of reference pathogens from an in-situ decay study. These variables along with literature data were then used in the static QMRA which demonstrated that the recovered water at this site did not meet the Australian Guidelines for recycled water when used for differing private green space irrigation scenarios. The results also confirmed the importance of obtaining local hydrogeological data as local heterogeneity can influence of residence time in the aquifer which, in turn, influences the outcomes. The research demonstrated that a static QMRA can be used to determine the residual risk from pathogens in recovered water and showed that it can be a valuable tool in the preliminary design and operation of MAR systems and the incorporation of complementary engineered treatment processes to ensure that there is acceptable health risk from the recovered water. Crown Copyright 2009. Published by Elsevier Ltd. All rights reserved.

  5. Experimental determinations of soil copper toxicity to lettuce (Lactuca sativa) growth in highly different copper spiked and aged soils

    DEFF Research Database (Denmark)

    Christiansen, Karen Søgaard; Borggaard, Ole K.; Holm, Peter Engelund

    2015-01-01

    Accurate knowledge about factors and conditions determining copper (Cu) toxicity in soil is needed for predicting plant growth in various Cu-contaminated soils. Therefore, effects of Cu on growth (biomass production) of lettuce (Lactuca sativa) were tested on seven selected, very different soils...

  6. Effect of cobalt on the growth of Trichoderma viride and determination of its distribution using 60Co

    International Nuclear Information System (INIS)

    Frank, V.; Lesny, J.; Babej, L.

    1993-01-01

    The growth and morphology of filamentous fungus Trichoderma viride grown in the presence of various Co concentrations were studied. Using 60 Co, the cobalt content in mycelium and conidia was determined. No influence of 60 Co-radiation on growth and morphology was observed. (author) 5 refs.; 4 figs

  7. Determination of specific growth stages of plant cell suspension cultures by monitoring conductivity changes in the medium.

    Science.gov (United States)

    Hahlbrock, K; Ebel, J; Oaks, A; Auden, J; Liersch, M

    1974-03-01

    Conductivity changes in the medium of cultured soybean (Glycine max L.) cells were shown to be strictly correlated with nitrate uptake and growth of the cultures. A continuous record of the conductivity was used as a simple and reliable method of determining specific growth stages and concomitant peaks in the activities of nitrate reductase and phenylalanine ammonia-lyase.

  8. Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods.

    Science.gov (United States)

    Gonzaga, Carla Castiglia; Cesar, Paulo Francisco; Miranda, Walter Gomes; Yoshimura, Humberto Naoyuki

    2011-11-01

    This study compared three methods for the determination of the slow crack growth susceptibility coefficient (n) of two veneering ceramics (VM7 and d.Sign), two glass-ceramics (Empress and Empress 2) and a glass-infiltrated alumina composite (In-Ceram Alumina). Discs (n = 10) were prepared according to manufacturers' recommendations and polished. The constant stress-rate test was performed at five constant stress rates to calculate n(d) . For the indentation fracture test to determine n(IF) , Vickers indentations were performed and the crack lengths were measured under an optical microscope. For the constant stress test (performed only for d.Sign for the determination of n(s) ) four constant stresses were applied and held constant until the specimens' fracture and the time to failure was recorded. All tests were performed in artificial saliva at 37°C. The n(d) values were 17.2 for Empress 2, followed by d.Sign (20.5), VM7 (26.5), Empress (30.2), and In-Ceram Alumina (31.1). In-Ceram Alumina and Empress 2 showed the highest n(IF) values, 66.0 and 40.2, respectively. The n(IF) values determined for Empress (25.2), d.Sign (25.6), and VM7 (20.1) were similar. The n(s) value determined for d.Sign was 31.4. It can be concluded that the n values determined for the dental ceramics evaluated were significantly influenced by the test method used. 2011 Wiley Periodicals, Inc.

  9. Microbial flora analysis for the degradation of beta-cypermethrin.

    Science.gov (United States)

    Qi, Zhang; Wei, Zhang

    2017-03-01

    In the Xinjiang region of Eurasia, sustained long-term and continuous cropping of cotton over a wide expanse of land is practiced, which requires application of high levels of pyrethroid and other classes of pesticides-resulting in high levels of pesticide residues in the soil. In this study, soil samples were collected from areas of long-term continuous cotton crops with the aim of obtaining microbial resources applicable for remediation of pyrethroid pesticide contamination suitable for the soil type and climate of that area. Soil samples were first used to culture microbial flora capable of degrading beta-cypermethrin using an enrichment culture method. Structural changes and ultimate microbial floral composition during enrichment were analyzed by high-throughput sequencing. Four strains capable of degrading beta-cypermethrin were isolated and preliminarily classified. Finally, comparative rates and speeds of degradation of beta-cypermethrin between relevant microbial flora and single strains were determined. After continuous subculture for 3 weeks, soil sample microbial flora formed a new type of microbial flora by rapid succession, which showed stable growth by utilizing beta-cypermethrin as the sole carbon source (GXzq). This microbial flora mainly consisted of Pseudomonas, Hyphomicrobium, Dokdonella, and Methyloversatilis. Analysis of the microbial flora also permitted separation of four additional strains; i.e., GXZQ4, GXZQ6, GXZQ7, and GXZQ13 that, respectively, belonged to Streptomyces, Enterobacter, Streptomyces, and Pseudomonas. Under culture conditions of 37 °C and 180 rpm, the degradation rate of beta-cypermethrin by GXzq was as high as 89.84% within 96 h, which exceeded that achieved by the single strains GXZQ4, GXZQ6, GXZQ7, and GXZQ13 and their derived microbial flora GXh.

  10. Initial studies to assess microbial impacts on nuclear waste disposal

    International Nuclear Information System (INIS)

    Horn, J.M.; Meike, A.; McCright, R.D.; Economides, B.

    1996-01-01

    The impacts of the native and introduced bacteria on the performance of geologic nuclear waste disposal facilities should be evaluated because these bacteria could promote corrosion of repository components and alteration of chemical and hydrological properties of the surrounding engineered and rock barriers. As a first step towards investigating these potentialities, native and introduced bacteria obtained from post-construction Yucca Mountain (YM) rock were isolated under varying conditions, including elevated temperature, low nutrient availability, and the absence of available oxygen. Individual isolates are being screened for activities associated with microbially induced corrosion of metals (MIC). Preliminary determination of growth rates of whole YM microbial communities under varying conditions was also undertaken

  11. DETERMINANTS OF HEALTHCARE EXPENDITURE ON HUMAN CAPITAL AND ECONOMIC GROWTH IN BANGLADESH: A LONGITUDINAL DATA ANALYSIS FROM 1995-2010

    OpenAIRE

    SHONGKOUR ROY

    2014-01-01

    The objective of this study was to examine the determinants of healthcare expenditure in Bangladesh between 1995 and 2010 byapplying the World development indicator data. First, I developed an empirical model for longitudinal data analysis to determinant thehealthcare expenditure under the human capital and economic growth. Next, I explored the dynamic relationships among healthcareexpenditure, human capital and economic growth usingOLSmodel. The expenditure in private healthcare was 2.3% and...

  12. Efficacy of otoliths and first dorsal spines for preliminary age and growth determination in Atlantic Tripletails

    Science.gov (United States)

    Parr, Russell T.; Bringolf, Robert B.; Jennings, Cecil A.

    2018-01-01

    The Atlantic Tripletail Lobotes surinamensis is a popular sport fish for which age and growth data are scarce in general and nonexistent for Georgia (GA), USA, waters. These data are necessary to ensure that management regulations are adequate to protect this species, especially given its popularity as a sport fish. We evaluated whether otoliths and spines were suitable for determining the estimated age (hereafter, “age”) and growth rates of Atlantic Tripletails, and we ascertained whether one method was more accurate than the other. Atlantic Tripletails were sampled by angling and trawling during March 30–August 10, 2009, and March 14–August 6, 2010, in nearshore GA waters of the Atlantic Ocean. During the study, 243 Atlantic Tripletails were captured and sampled for aging structures. Sagittal otoliths and the first dorsal spine were removed from each fish and used to estimate the age and growth rate. Mean differences in TL at age for spine and otolith data were evaluated with ANOVA. Estimated ages for males and females ranged from 1 to 5 years based on otoliths and spines. Both otolith and spine mean TLs at ages 1 and 2 were significantly different from each other as well as all other age‐classes, whereas mean TLs for ages 3–5 were not significantly different. Differences in Atlantic Tripletail TL among the otolith‐ and spine‐derived age‐classes were not significant. Each method used to age Atlantic Tripletails had advantages and disadvantages. Otoliths had higher initial reader agreement than spines, although agreement between the structures was 84.1%. However, otoliths require sacrifice of the fish, whereas a spine can be taken without sacrificing the fish. The lack of concrete life history data and population estimates suggests that when feasible, nonlethal aging methods would be preferred over lethal methods to ensure the survival of Atlantic Tripletail populations.

  13. Deficient Circumferential Growth Is the Primary Determinant of Aortic Obstruction Attributable to Partial Elastin Deficiency.

    Science.gov (United States)

    Jiao, Yang; Li, Guangxin; Korneva, Arina; Caulk, Alexander W; Qin, Lingfeng; Bersi, Matthew R; Li, Qingle; Li, Wei; Mecham, Robert P; Humphrey, Jay D; Tellides, George

    2017-05-01

    Williams syndrome is characterized by obstructive aortopathy attributable to heterozygous loss of ELN , the gene encoding elastin. Lesions are thought to result primarily from excessive smooth muscle cell (SMC) proliferation and consequent medial expansion, although an initially smaller caliber and increased stiffness of the aorta may contribute to luminal narrowing. The relative contributions of such abnormalities to the obstructive phenotype had not been defined. We quantified determinants of luminal stenosis in thoracic aortas of Eln -/- mice incompletely rescued by human ELN . Moderate obstruction was largely because of deficient circumferential growth, most prominently of ascending segments, despite increased axial growth. Medial thickening was evident in these smaller diameter elastin-deficient aortas, with medial area similar to that of larger diameter control aortas. There was no difference in cross-sectional SMC number between mutant and wild-type genotypes at multiple stages of postnatal development. Decreased elastin content was associated with medial fibrosis and reduced aortic distensibility because of increased structural stiffness but preserved material stiffness. Elastin-deficient SMCs exhibited greater contractile-to-proliferative phenotypic modulation in vitro than in vivo. We confirmed increased medial collagen without evidence of increased medial area or SMC number in a small ascending aorta with thickened media of a Williams syndrome subject. Deficient circumferential growth is the predominant mechanism for moderate obstructive aortic disease resulting from partial elastin deficiency. Our findings suggest that diverse aortic manifestations in Williams syndrome result from graded elastin content, and SMC hyperplasia causing medial expansion requires additional elastin loss superimposed on ELN haploinsufficiency. © 2017 American Heart Association, Inc.

  14. Colorimetric determination of staphylococcal enterotoxin B via DNAzyme-guided growth of gold nanoparticles

    International Nuclear Information System (INIS)

    Zhou, Dandan; Chen, Hui; Xie, Guoming; Cao, Xianqing; Chen, Xueping; Zhang, Xing

    2016-01-01

    The authors describe a colorimetric method for the determination of the staphylococcal enterotoxin B (SEB) that also allows for visual readout. The assay is based on the growth of gold nanoparticles (AuNPs) mediated by a hemin/G-quadruplex DNAzyme which generates a color change from red to blue in the presence of SEB. The method is enzyme-free and does not require a label. The kinetics of the formation of the AuNPs is controlled by the hemin/G-quadruplex DNAzyme and this is key to the signal generation mechanism. In the presence of SEB, the reactions between aptamer and target modulated the amount of single probe G strands that form DNAzyme capable of consuming hydrogen peroxide. The growth process of AuNPs is influenced by the resulting concentration of H 2 O 2 and leads to the color change. Under optimal conditions, a linear relationship exists between absorbance and SEB concentration in the range from 0.1 to 500 pg·mL -1 which covers the clinically relevant range. In case of visual detection, the lower limit of detection is 1 pg·mL −1 . The assay described here is sensitive, comparably inexpensive and can detect SEB rapidly without the need for sophisticated equipment. In our perception, the method has a wide scope in that it may be adapted to various nucleic acids, proteins and other biomolecules if respective aptamers are available. (author)

  15. Thermosensitivity of growth is determined by chaperone-mediated proteome reallocation

    Science.gov (United States)

    Chen, Ke; Gao, Ye; Mih, Nathan; O’Brien, Edward J.; Yang, Laurence; Palsson, Bernhard O.

    2017-01-01

    Maintenance of a properly folded proteome is critical for bacterial survival at notably different growth temperatures. Understanding the molecular basis of thermoadaptation has progressed in two main directions, the sequence and structural basis of protein thermostability and the mechanistic principles of protein quality control assisted by chaperones. Yet we do not fully understand how structural integrity of the entire proteome is maintained under stress and how it affects cellular fitness. To address this challenge, we reconstruct a genome-scale protein-folding network for Escherichia coli and formulate a computational model, FoldME, that provides statistical descriptions of multiscale cellular response consistent with many datasets. FoldME simulations show (i) that the chaperones act as a system when they respond to unfolding stress rather than achieving efficient folding of any single component of the proteome, (ii) how the proteome is globally balanced between chaperones for folding and the complex machinery synthesizing the proteins in response to perturbation, (iii) how this balancing determines growth rate dependence on temperature and is achieved through nonspecific regulation, and (iv) how thermal instability of the individual protein affects the overall functional state of the proteome. Overall, these results expand our view of cellular regulation, from targeted specific control mechanisms to global regulation through a web of nonspecific competing interactions that modulate the optimal reallocation of cellular resources. The methodology developed in this study enables genome-scale integration of environment-dependent protein properties and a proteome-wide study of cellular stress responses. PMID:29073085

  16. Proposal for new climate agreements: Economic growth determines the emission quota

    International Nuclear Information System (INIS)

    Kallbekken, Steffen; Tjernshaugen, Andreas

    2002-01-01

    Long-term obligations to curb the emission of climate gases involve economic uncertainty because it is difficult to determine the cost of future reductions. This may be the principle reason why the USA and the developing countries are reluctant to accept binding demands on their emissions of climate gases. For example, the commitments of the Kyoto Protocol were agreed upon more than ten years before they shall be put to force. Over such a long time span it is impossible to predict the development of the economy as well as the gas emissions. Usually economical development leads to increased gas emission. If a country commits itself to a quantified limit on its emission, and the economical development turns out to be much faster than predicted, then living up to the commitments may be very expensive. The same is true if the economic growth occurs in the polluting sectors to a larger degree than expected. Many heads of state thus fear that binding emission targets may restrain economic growth

  17. Age determination in manatees using growth-layer-group counts in bone

    Science.gov (United States)

    Marmontel, M.; O'Shea, T.J.; Kochman, H.I.; Humphrey, S.R.

    1996-01-01

    Growth layers were observed in histological preparations of bones of known-age, known minimum-age, and tetracycline-marked free-ranging and captive Florida manatees (Trichechus manatus latirostris), substantiating earlier preliminary findings of other studies. Detailed analysis of 17 new case histories showed that growth-layer group (GLG) counts in the periotic bone were consistent with known age, or time since tetracycline administration, but were less reliable in other bones. GLG counts were also made in periotic bones of 1,196 Florida manatees of unknown age found dead from 1974 through 1991. These counts were conducted in order to assess variability and to determine relationships among estimated age, size, sex, and degree of bone resorption. Resorption can interfere with accuracy of GLG counts. This effect does not occur until ages greater than about 15 yr and body lengths greater than 300 cm are attained. GLGs were also observed in periotic bones of Antillean manatees (Trichechus manatus manatus) but were not validated against known-age specimens. Use of GLG counts in the periotic bone is suitable for application to studies of population dynamics and other age-related aspects of manatee biology.

  18. THE GROWTH RATE OF PUBLIC DEBT IN ROMANIA - DETERMINANT OF A REAL STRATEGY MANAGEMENT

    Directory of Open Access Journals (Sweden)

    DOBROT;ăGABRIELA

    2017-12-01

    Full Text Available Contracting public debt is an omnipresent process in Member emerging. Low development of production capacities compared to consumption and investment, the existence of a reduced volume of savings internally, major imbalances in external plan or fluctuations in major capital are just some elements that determine the the orientation towards borrowings, and in particular to external funding. The growth rate in recent years emphasized, representing an issue of major importance for authorities, especially considering the sustainability of government debt. This may be evidenced at least by analysis of the level registered, of cost of financing and repayment period. In the paper is performed a descriptive statistical analysis on the evolution of growth in public debt and its structure by types of currencies, being presented and the factors affecting the maintenance of public debt to a sustainable level. The conclusion of the analysis carried out highlights a rapidly growing of the public debt in Romania after 2008, which requires the application of a clear strategy for its management so as to avoid the generated risks by high levels and inadequate structure.

  19. Posttraumatic Growth and Bereavement: The Contribution of Self-Determination Theory.

    Science.gov (United States)

    Lumb, Andrew B; Beaudry, Myriam; Blanchard, Celine

    2017-09-01

    No research drawing from Self-Determination Theory has investigated the bereavement experience of individuals or how motivation can help facilitate posttraumatic growth (PTG) following the death of a loved one. In two cross-sectional studies, university students completed an online survey. Study 1 investigated the contribution of global autonomous and controlled motivation in statistically predicting PTG above and beyond previously researched correlates. Study 2 explored the mediating role of cognitive appraisals and coping in explaining the relationship between global motivation orientations and PTG. Results indicated that in comparison to controlled motivation, autonomous motivation was positively related PTG, even after controlling for previously researched correlates. Mediation results indicated an indirect effect of global autonomous motivation on PTG through task-oriented coping. Collectively, these findings suggest the importance of incorporating motivation into models of PTG. Clinical implications of these findings are also discussed.

  20. Determination of serum insulinlike growth factor II levels in coronary heart disease patient and its significance

    International Nuclear Information System (INIS)

    Fan Bifu; Ji Naijun; Mei Yibin; Wang Chengyao; Zhao Junfei; Guan Lihua; Gao Meiying; Li Jiangao

    2002-01-01

    Objective: To explore the changes and clinical significance of serum insulinlike growth factor II (IGF II) levels in coronary heart disease (CHD) patients. Methods: The serum IGF II levels were determined by radioimmunoassay in 68 patients with coronary heart disease (CHD) and 30 controls with only mild non-cardiac diseases. Results: Compared with the controls, the serum IGF II level in CHD patients were increased significantly (0.66 ± 0.13 μg/L vs 0.51 ± 0.11 μg/L; t = 5.506, p 0.05). Level in patients dies in hospital (n = 9) were much higher than those in patients recovered (n = 59) (t = 2.402, p < 0.05). Conclusion: Serum IGF II levels seems to be related to the seriousness of CHD; the actual mechanism remains to be defined

  1. Determination of the Minimum Inhibitory Concentration of the Barberry Extract and the Dried Residue of Red Grape and Their Effects on the Growth Inhibition of Sausage Bacteria by Using Response Surface Methodology (RSM

    Directory of Open Access Journals (Sweden)

    Fatemeh Riazi

    2015-09-01

    Full Text Available Background and Objectives: With regard to the hazards of nitrite, application of natural preservatives in order to reduce the microbial load of meat and meat products is increasing. Owing to their anti-bacterial properties, red barberry and the dried residue of red grape could be suitable replacers for nitrite. Materials and Methods: Agar dilution method was employed in order to determine the minimum inhibitory concentration (MIC of the barberry extract and the dried residue of red grape. The anti-microbial effects of the barberry extract (0-600 mg/kg, the dried residue of red grape (0-2% and nitrite (30-90 mg/kg were investigated on the total viable counts of Clostridium perfringens, as well as on the psychrophilic bacteria after 30 days of storage at 4°C. Finally, the effects of the three independent variables in the optimal sample were examined on the growth of the inoculated C. perfringens. Results: The MIC of the barberry extract and the dried residue of red grape on Staphylococcus aureus was 3 and 6 (mg/ml, respectively. In the case of Escherichia coli, it was 4 and 7 (mg/ml, respectively. The barberry extract and nitrite reduced the growth of the living aerobic bacteria significantly. The spores of the inoculated C. perfringens had no growth in the optimum sample during storage. Conclusions: The barberry extract and the dried residue of red grape as natural preservatives, could partially substitute for nitrite in order to reduce the microbial load of sausage.

  2. ERS-1 SAR monitoring of ice growth on shallow lakes to determine water depth and availability in north west Alaska

    Science.gov (United States)

    Jeffries, Martin; Morris, Kim; Liston, Glen

    1996-01-01

    Images taken by the ERS-1 synthetic aperture radar (SAR) were used to identify and to differentiate between the lakes that freeze completely to the bottom and those that do not, on the North Slope, in northwestern Alaska. The ice thickness at the time each lake froze completely is determined with numerical ice growth model that gives a maximum simulated thickness of 2.2 m. A method combining the ERS-1 SAR images and numerical ice growth model was used to determine the ice growth and the water availability in these regions.

  3. Effects of Bacillus subtilis-based direct-fed microbials on growth performance, immune characteristics and resistance against experimental coccidiosis in broiler chickens

    Science.gov (United States)

    The present experiment was conducted to study the effects of dietary Bacillus-based direct-fed microbials (DFMs) on cytokine expression patterns, intestinal intraepithelial lymphocyte (IEL) subpopulation, splenocyte proliferation, macrophage functions and resistance against experimental coccidiosis ...

  4. Determinants of infant growth in Eastern Uganda: a community-based cross-sectional study

    Directory of Open Access Journals (Sweden)

    Engebretsen Ingunn

    2008-12-01

    Full Text Available Abstract Background Child under-nutrition is a leading factor underlying child mortality and morbidity in Sub-Saharan Africa. Several studies from Uganda have reported impaired growth, but there have been few if any community-based infant anthropometric studies from Eastern Uganda. The aim of this study was to describe current infant growth patterns using WHO Child Growth Standards and to determine the extent to which these patterns are associated with infant feeding practices, equity dimensions, morbidity and use of primary health care for the infants. Methods A cross-sectional survey of infant feeding practices, socio-economic characteristics and anthropometric measurements was conducted in Mbale District, Eastern Uganda in 2003; 723 mother-infant (0–11 months pairs were analysed. Infant anthropometric status was assessed using z-scores for weight-for-length (WLZ, length-for-age (LAZ and weight-for-age (WAZ. Dependent dichotomous variables were constructed using WLZ Results The prevalences of wasting and stunting were 4.2% and 16.7%, respectively. Diarrhoea during the previous 14 days was associated with wasting in the crude analysis, but no factors were significantly associated with wasting in the adjusted analysis. The adjusted analysis for stunting showed associations with age and gender. Stunting was more prevalent among boys than girls, 58.7% versus 41.3%. Having brothers and/or sisters was a protective factor against stunting (OR 0.4, 95% CI 0.2–0.8, but replacement or mixed feeding was not (OR 2.7, 95% CI 1.0–7.1. Lowest household wealth was the most prominent factor associated with stunting with a more than three-fold increase in odds ratio (OR 3.5, 95% CI 1.6–7.8. This pattern was also seen when the mean LAZ was investigated across household wealth categories: the adjusted mean difference between the top and the bottom wealth categories was 0.58 z-scores, p Conclusion Sub-optimal infant feeding practices after birth, poor

  5. Growth pattern and structural nature of amylases produced by some ...

    African Journals Online (AJOL)

    The growth pattern and microbial biomass formed during metabolic activities of the Bacillus species on starchy substrates was determined. The result showed that the strains B. subtilis (WBS), B. licheniformis (WBL) and B. coagulans (MBC) generally had high growth rate. B. circulans (SBC) and B. coagulans (WBC) has ...

  6. Volume doubling time and growth rate of renal cell carcinoma determined by helical CT: a single-institution experience

    International Nuclear Information System (INIS)

    Lee, Ji Young; Kim, Chan Kyo; Choi, Dongil; Park, Byung Kwan

    2008-01-01

    The purpose of this study was to retrospectively evaluate the volume doubling time (VDT) and growth rate of renal cell carcinomas (RCC) on a serial computed tomography (CT) scan. Thirty pathologically proven RCCs were reviewed with helical CT. Each tumor underwent at least two CT scans. Tumor volume was determined using an area measuring tool and the summation-of-areas technique. Growth rate was evaluated in terms of diameter and volume changes. VDT and volume growth rate were compared in relation to several factors (initial diameter, initial volume, diameter growth rate, volume growth rate, tumor grade, tumor subtype, sex or age). Mean VDT of RCCs was 505 days. Mean diameter and volume growth rate were 0.59 cm/year and 19.1 cm 3 /year, respectively. For volume and diameter growth rate, tumors ≤4 cm showed lower rates than those >4 cm (P 0.05). Volume growth rate was moderately to strongly positively correlated with initial diameter, initial volume and diameter growth rate (P < 0.05). In conclusion, small RCCs grew at a slow rate both diametrically and volumetrically. More accurate assessment of tumor growth rate and VDT may be helpful to understand the natural history of RCC. (orig.)

  7. Modelling and predicting growth of psycrotolerant pseudomonads in milk and cottage cheese

    DEFF Research Database (Denmark)

    Martinez Rios, Veronica; Østergaard, Nina Bjerre; Rosshaug, Per Sand

    2015-01-01

    Introduction: Predictive food microbiology models have the potential to evaluate the effect of temperature on microbial growth during distribution as well as be used to determine how product characteristics can be modified to reduce growth to an acceptable level. Methods: Growth kinetics of psych...

  8. Microbial deterioration of Mayan stone buildings at Uxmal, Yucatan, Mexico

    International Nuclear Information System (INIS)

    Ortega-Morales, O.; Guezennec, J.; Hernandez D, G.; Jozsa, P.; Sand, W.; Crassous, P.

    1998-01-01

    The microbial communities associated to Uxmal Mayan monuments (Yucatan, Mexico) and their role in stone deterioration were preliminary characterized by chemical, biochemical, microbiological, microscopical and surface analysis methods under two climatic seasons (1997). The organic matter and organic carbon and nitrogen were in the range of those reported for other stone buildings, indicating that oligo trophic conditions prevail at Uxmal. Quantitative differences in microbial biomass was higher at indoor section were the organic matter content was the highest and micro-environmental conditions (availability of water and protection to direct sunlight) are more suitable for microbial growth. The microbiological analysis underestimated the microbial biomass, as revealed by biochemical approaches. Nitrate and nitrite-oxidizing, metilotrophic and heterotrophic bacteria and fungi were detected in most surfaces. The heterotrophic bacteria were the most abundant microbial group (microbiological data). However, the chlorophyll profiles and Scanning Electron Microscopy showed that the microalgae are the most abundant colonizers in Uxmal stone buildings. EDAX analysis showed that the most surfaces were covered by an organic layer (cells and exo polymers). Gypsum was found in few samples. The large photo trophic biomass seems to play a role in stone bio deterioration by supporting growth of heterotrophic microorganisms (bacteria and fungi) which are known to produce organic acids leading to calcite dissolution and cations chelation. Further studies are being carried out in order to determine the role of exo polysaccharides which are thought to play a role in chemical degradation of limestone substrates in Uxmal. (Author)

  9. Determination of the algal growth-limiting nutrients in strip mine ponds

    International Nuclear Information System (INIS)

    Bucknavage, M.J.; Aharrah, E.C.

    1984-01-01

    Using both a test organism, Ankistrodesmus falcatus, and natural phytoplankton, the Printz Algal Assay Bottle Test was used to determine the algal growth limiting nutrients in two strip mine ponds. Nitrogen, phosphorus, and iron were investigated, singly and in combination, as possible limiting nutrients. A synthetic chelator, Na 2 EDTA, was also used in the assay to test for the presence of metal toxicants and/or trace metal limitation. Because bacteria have a major influence on water chemistry, a separate assay incorporating the natural bacteria population was performed. In both ponds, assay results using test alga indicate phosphorus to be the primary limiting nutrient and nitrogen as a secondary factor. The presence of EDTA in combination with phosphate containing treatment promoted a higher algal concentration in both ponds. Iron was determined to be a secondary limiting nutrient in only one of the ponds. Natural phytoplankton of the two ponds responded in a similar manner to nutrient increases. Only one pond had the same results produced by both assays. Nutrient availability was influenced by the presence of bacteria in one pond but not in the other

  10. Balance between Apical Membrane Growth and Luminal Matrix Resistance Determines Epithelial Tubule Shape

    Directory of Open Access Journals (Sweden)

    Bo Dong

    2014-05-01

    Full Text Available The morphological stability of biological tubes is crucial for the efficient circulation of fluids and gases. Failure of this stability causes irregularly shaped tubes found in multiple pathological conditions. Here, we report that Drosophila mutants of the ESCRT III component Shrub/Vps32 exhibit a strikingly elongated sinusoidal tube phenotype. This is caused by excessive apical membrane synthesis accompanied by the ectopic accumulation and overactivation of Crumbs in swollen endosomes. Furthermore, we demonstrate that the apical extracellular matrix (aECM of the tracheal tube is a viscoelastic material coupled with the apical membrane. We present a simple mechanical model in which aECM elasticity, apical membrane growth, and their interaction are three vital parameters determining the stability of biological tubes. Our findings demonstrate a mechanical role for the extracellular matrix and suggest that the interaction of the apical membrane and an elastic aECM determines the final morphology of biological tubes independent of cell shape.

  11. Balance between apical membrane growth and luminal matrix resistance determines epithelial tubule shape.

    Science.gov (United States)

    Dong, Bo; Hannezo, Edouard; Hayashi, Shigeo

    2014-05-22

    The morphological stability of biological tubes is crucial for the efficient circulation of fluids and gases. Failure of this stability causes irregularly shaped tubes found in multiple pathological conditions. Here, we report that Drosophila mutants of the ESCRT III component Shrub/Vps32 exhibit a strikingly elongated sinusoidal tube phenotype. This is caused by excessive apical membrane synthesis accompanied by the ectopic accumulation and overactivation of Crumbs in swollen endosomes. Furthermore, we demonstrate that the apical extracellular matrix (aECM) of the tracheal tube is a viscoelastic material coupled with the apical membrane. We present a simple mechanical model in which aECM elasticity, apical membrane growth, and their interaction are three vital parameters determining the stability of biological tubes. Our findings demonstrate a mechanical role for the extracellular matrix and suggest that the interaction of the apical membrane and an elastic aECM determines the final morphology of biological tubes independent of cell shape. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Microbial biosensors

    International Nuclear Information System (INIS)

    Le Yu; Chen, Wilfred; Mulchandani, Ashok

    2006-01-01

    A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

  13. The Effect of Government Debt and Other Determinants on Economic Growth: The Greek Experience

    Directory of Open Access Journals (Sweden)

    Panagiotis Pegkas

    2018-02-01

    Full Text Available This study empirically investigates the relationship between economic growth and several factors (investment, private and government consumption, trade openness, population growth and government debt in Greece, where imbalances persist several years after the financial crisis. The results reveal a long-run relationship between variables. Investment as private and government consumption and trade openness affect positively growth. On the other hand, there is a negative long-run effect of government debt and population growth on growth. Furthermore, the study addresses the issue of break effects between government debt and economic growth. The results indicate that the relationship between debt and growth depends on the debt breaks. Specifically, at debt levels before 2000, increases in the government debt-to-GDP ratio are associated with insignificant effects on economic growth. However, as government debt rises after 2000, the effect on economic growth diminishes rapidly and the growth impacts become negative. The challenge for policy makers in Greece is to halt the rising of government debt by keeping a sustainable growth path. Fiscal discipline should be combined with the implementation of coherent, consistent and sequential growth-enhancing structural reforms.

  14. Use of the Delphi method for determining community growth goals inventory: the Nashville experience

    Science.gov (United States)

    Vishwa K. Varma

    1977-01-01

    The author discusses the growth-inducing pressures on Nashville, Tennessee, describes the application of the Delphi technique to develop an inventory of the community's growth goals, and suggests that the development of a list of community goals is a necessary first step toward growth management.

  15. Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

    Directory of Open Access Journals (Sweden)

    Simone Vincenzi

    2014-09-01

    Full Text Available The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth and L∞ (asymptotic size. Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC, the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

  16. Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

    Science.gov (United States)

    Vincenzi, Simone; Mangel, Marc; Crivelli, Alain J; Munch, Stephan; Skaug, Hans J

    2014-09-01

    The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups) determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth) and L∞ (asymptotic size). Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC), the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

  17. Contribution on the study of microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers

    International Nuclear Information System (INIS)

    Spor, H.

    1994-05-01

    The aim of this work is to study the different interactions mechanisms between microorganisms and radioelements in conditions similar to those of a radioactive waste disposal site and to determine all the mechanisms due to microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers. In this work are presented the different following points: - a bibliographic study on the microorganisms-radioelements interactions; - the conditions of metabolites production during the microbial growth (influence of the nature of the carbonated source, pH effects, aerobiosis conditions...); the mechanisms of a direct effect for determining the importance of the bio-sorption mechanism by microorganisms; the fact that the microbial biomass can strongly interact with actinides, heavy metals and radioelements; the effects of microorganisms on storage materials (cement and clay) containing radioelements (uranium, cesium); the complexation capacities of the organic and mineral acids produced during the microbial growth. (O.M.)

  18. Growth performance, duodenal morphology and the caecal microbial population in female broiler chickens fed glycine-fortified low protein diets under heat stress conditions.

    Science.gov (United States)

    Awad, E A; Idrus, Z; Soleimani Farjam, A; Bello, A U; Jahromi, M F

    2018-03-09

    1. This study was undertaken to examine the effect of feeding glycine (Gly)-fortified low protein (LP) diets on the growth performance, duodenal morphology and caecal microbial populations of broiler chickens raised under unheated, cyclic or constant heat stress environmental conditions. 2. From d 1 to 21 (starter phase), an equivalent number of birds were fed either a normal protein (NP) diet or a LP diet fortified with Gly. From d 22 to 42 (grower phase), an equivalent number of birds from each starter diet were distributed to one of the following dietary groups: (i) an NP diet during the starter and grower phases (NPNP), (ii) an NP diet during the starter phase and a LP diet during the grower phase (NPLP), (iii) an LP diet during the starter phase and an NP diet during the grower phase (LPNP) or (iv) LP diets during both phases (LPLP). 3. Commencing from d 22, an equivalent number of birds from each dietary group were exposed to (i) 23 ± 1°C throughout (unheated), (ii) 34 ± 1°C for 7 h each day from 10:00 to 17:00 (cyclic heat) or (iii) 34 ± 1°C throughout (constant heat). 4. Feeding the LP diet during the starter phase resulted in feed intake (FI), weight gain (WG), feed conversion ratios (FCR) and energy efficiency ratios (EER) similar to those for the NP diet. The birds fed the LP diet had a significantly higher protein efficiency ratio (PER) compared with the birds fed the NP diet. 5. During the grower phase, there were significant diet × temperature interactions for F, WG, FCR, PER, EER, villus height, crypt depth and caecal Clostridia. The birds fed the NPLP and LPLP diets had lower FI, WG and EER, higher FCR, shorter villus height and crypt depth and higher caecal Clostridia compared with the birds fed LPNP and NPNP diets under constant heat stress. However, feeding birds the NPLP and LPLP diets resulted in FI, WG, EER, FCR, morphology parameters and caecal Clostridia equivalent to the birds fed LPNP and NPNP diets, as well as improved PER

  19. Microbial incorporation of nitrogen in stream detritus

    Science.gov (United States)

    Diane M. Sanzone; Jennifer L. Tank; Judy L. Meyer; Patrick J. Mulholland; Stuart E.G. Findlay

    2001-01-01

    We adapted the chloroform fumigation method to determine microbial nitrogen (N) and microbial incorporation of 15N on three common substrates [leaves, wood and fine benthic organic matter (FBOM)] in three forest streams. We compared microbial N and 15 content of samples collected during a 6-week15N-NH...

  20. Determining the annual periodicity of growth rings in seven tree species of a tropical moist forest in Santa Cruz, Bolivia

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, L.; Villalba, R.; Pena-Claros, M.

    2012-07-01

    To determine the annual periodicity of growth rings in seven tree species from a tropical moist forest in Santa Cruz, Bolivia, a fire scar was used as a marker point to verify the annual nature of tree rings. The number of tree rings formed between the 1995 fire scar and the collection of the cross sections in 2002 was visually identified. The seven species showed annual growth rings. In most cases, boundaries between rings were marked by the presence of marginal parenchyma and wall-thick ed fibers formed at the end of the growing season. Growth lenses and false rings were recorded in some species. Tree rings can be carefully used in Santa Cruz forests to determine rates of growth. This information is crucial for defining forest management practices in tropical regions. (Author) 21 refs.

  1. Environmental modulation of autoimmune arthritis involves the spontaneous microbial induction of T cell responses to regulatory determinants within heat shock protein 65.

    Science.gov (United States)

    Moudgil, K D; Kim, E; Yun, O J; Chi, H H; Brahn, E; Sercarz, E E

    2001-03-15

    Both genetic and environmental factors are believed to be involved in the induction of autoimmune diseases. Adjuvant arthritis (AA) is inducible in susceptible rat strains by injection of Mycobacterium tuberculosis, and arthritic rats raise T cell responses to the 65-kDa mycobacterial heat-shock protein (Bhsp65). We observed that Fischer 344 (F344) rats raised in a barrier facility (BF-F344) are susceptible to AA, whereas F344 rats maintained in a conventional facility (CV-F344) show significantly reduced incidence and severity of AA, despite responding well to the arthritogenic determinant within Bhsp65. The acquisition of protection from AA can be circumvented if rats are maintained on neomycin/acidified water. Strikingly, naive unimmunized CV-F344 rats but not BF-F344 rats raised T cell responses to Bhsp65 C-terminal determinants (BCTD) (we have previously shown that BCTD are involved in regulation of acute AA in the Lewis rat); however, T cells of naive CV-F344 and BF-F344 gave a comparable level of proliferative response to a mitogen, but no response at all to an irrelevant Ag. Furthermore, adoptive transfer into naive BF-F344 rats of splenic cells of naive CV-F344 rats (restimulated with BCTD in vitro) before induction of AA resulted in a considerably reduced severity of AA. These results suggest that spontaneous (inadvertent) priming of BCTD-reactive T cells, owing to determinant mimicry between Bhsp65 and its homologues in microbial agents in the conventional environment, is involved in modulating the severity of AA in CV-F344 rats. These results have important implications in broadening understanding of the host-microbe interaction in human autoimmune diseases.

  2. Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

    Science.gov (United States)

    Laver, Rebecca J; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S

    2012-01-01

    Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

  3. Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

    Directory of Open Access Journals (Sweden)

    Rebecca J Laver

    Full Text Available Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis. The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

  4. Life-History and Spatial Determinants of Somatic Growth Dynamics in Komodo Dragon Populations

    Science.gov (United States)

    Laver, Rebecca J.; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S.

    2012-01-01

    Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world’s largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species. PMID:23028983

  5. Molecular determinants of epidermal growth factor binding: a molecular dynamics study.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Sanders

    Full Text Available The epidermal growth factor receptor (EGFR is a member of the receptor tyrosine kinase family that plays a role in multiple cellular processes. Activation of EGFR requires binding of a ligand on the extracellular domain to promote conformational changes leading to dimerization and transphosphorylation of intracellular kinase domains. Seven ligands are known to bind EGFR with affinities ranging from sub-nanomolar to near micromolar dissociation constants. In the case of EGFR, distinct conformational states assumed upon binding a ligand is thought to be a determining factor in activation of a downstream signaling network. Previous biochemical studies suggest the existence of both low affinity and high affinity EGFR ligands. While these studies have identified functional effects of ligand binding, high-resolution structural data are lacking. To gain a better understanding of the molecular basis of EGFR binding affinities, we docked each EGFR ligand to the putative active state extracellular domain dimer and 25.0 ns molecular dynamics simulations were performed. MM-PBSA/GBSA are efficient computational approaches to approximate free energies of protein-protein interactions and decompose the free energy at the amino acid level. We applied these methods to the last 6.0 ns of each ligand-receptor simulation. MM-PBSA calculations were able to successfully rank all seven of the EGFR ligands based on the two affinity classes: EGF>HB-EGF>TGF-α>BTC>EPR>EPG>AR. Results from energy decomposition identified several interactions that are common among binding ligands. These findings reveal that while several residues are conserved among the EGFR ligand family, no single set of residues determines the affinity class. Instead we found heterogeneous sets of interactions that were driven primarily by electrostatic and Van der Waals forces. These results not only illustrate the complexity of EGFR dynamics but also pave the way for structure-based design of

  6. The role of microbial community composition and groundwater chemistry in determining isoproturon degradation potential in UK aquifers.

    Science.gov (United States)

    Johnson, Andrew; Llewellyn, Neville; Smith, Jennifer; van der Gast, Christopher; Lilley, Andrew; Singer, Andrew; Thompson, Ian

    2004-07-01

    The community response of indigenous sandstone, chalk and limestone groundwater microorganisms to the addition of the commonly used herbicide isoproturon was examined. The addition of 100 microg l(-1) isoproturon generally caused an increase in species diversity determined by chemotaxonomic analysis (fatty methyl ester analysis) of isolates resulting from incubation of cultures at 18 degrees C for 4 days. Amongst the groundwater samples to which isoproturon was added, isoproturon degradation rates were correlated with increasing dominance of a few species. However, the changes in community profile associated with isoproturon degradation varied from site to site. Repeated sub-culturing with 100 microg l(-1) isoproturon and sterile groundwater was carried out to examine whether this level of pesticide could exert a selection pressure, and hence stimulate more rapid degradation. Significantly increased degradation was observed in a groundwater sample from the chalk, but not in sandstone, or limestone samples. The addition of filter-sterilised sandstone groundwater to bacteria on filter paper from slow degrading limestone sites significantly improved their degrading performance. The addition of filter-sterilised limestone groundwater to the sandstone bacteria reduced their degradation rate only slightly. The data suggested that the nature of the indigenous community does influence pesticide degradation in groundwater, but that the groundwater chemistry may also play a role.

  7. Changes in Microbial Plankton Assemblages Induced by Mesoscale Oceanographic Features in the Northern Gulf of Mexico.

    Directory of Open Access Journals (Sweden)

    Alicia K Williams

    Full Text Available Mesoscale circulation generated by the Loop Current in the Northern Gulf of Mexico (NGOM delivers growth-limiting nutrients to the microbial plankton of the euphotic zone. Consequences of physicochemically driven community shifts on higher order consumers and subsequent impacts on the biological carbon pump remain poorly understood. This study evaluates microbial plankton <10 μm abundance and community structure across both cyclonic and anti-cyclonic circulation features in the NGOM using flow cytometry (SYBR Green I and autofluorescence parameters. Non-parametric multivariate hierarchical cluster analyses indicated that significant spatial variability in community structure exists such that stations that clustered together were defined as having a specific 'microbial signature' (i.e. statistically homogeneous community structure profiles based on relative abundance of microbial groups. Salinity and a combination of sea surface height anomaly and sea surface temperature were determined by distance based linear modeling to be abiotic predictor variables significantly correlated to changes in microbial signatures. Correlations between increased microbial abundance and availability of nitrogen suggest nitrogen-limitation of microbial plankton in this open ocean area. Regions of combined coastal water entrainment and mesoscale convergence corresponded to increased heterotrophic prokaryote abundance relative to autotrophic plankton. The results provide an initial assessment of how mesoscale circulation potentially influences microbial plankton abundance and community structure in the NGOM.

  8. Intellectual Properties Rights-A strong determinant of economic growth in agriculture

    Directory of Open Access Journals (Sweden)

    Love Kumar Singh

    2010-01-01

    Full Text Available In the past few decades the subject of intellectual property rights (IPRs has occupied center stage in debates about globalization, economic development and poverty elimination. This study concerns the strengthening of IPRs in the plant breeding industry and its effect on agriculture in India. In India, most of the population relies on agricul-ture for its livelihood. India is self-sufficient in wheat and paddy, but deficient in other agricultural products. Pat-ents are good indicators of research and development output. Patent analysis makes it possible to map out the trend of technological change and life cycle of a technology - growth, development, maturity and decline. Patent infor-mation and patent statistical analysis have been used for examining present, technological status and to forecast future trends. One can determine the directions of corporate R&D and market interests by analyzing patent data. The present study is an attempt to analyze patents granted in India in the field of agriculture and importance of biotechnology-based innovations in agriculture

  9. Determination of serum leptin and vascular endothelial growth factor (VEGF) contents in patients with breast cancer

    International Nuclear Information System (INIS)

    Huang Xudong; Jin Wentao; Pan Meizhen

    2006-01-01

    Objective: To investigate the serum expression of leptin and vascular endothelial growth factor (VEGF) in patients with breast cancer and assess its diagnostic significance. Methods: Thirty-six patients with breast cancer and thirty-one patients with benign breast disorders entered this study. Serum concentration of leptin (with RIA) and VEGF ( with ELISA) were determined in these patients before operation as well as in 56 controls. All the tested subjects were post-menopausal women. Results: The difference between the leptin levels in the controls and patients with benign breast disorders was significantly; 80 was the difference between the leptin levels in controls and patients with breast cancer. Significant difference also existed between the VEGF levels in controls and patients with cancer as well as between the levels in patients with benign breast disease and patients with cancer. Also, the serum leptin and VEGF levels in the cancerous patients with axillary metastasis were significantly higher than those in patients without metastasis. Conclusion: Serum leptin and VEGF might be taken as diagnostic tumor markers for malignanay and metastasis in patients with breast cancer. (authors)

  10. Urinary growth hormone levels in children with leukemia determined by a sensitive sandwich enzyme immunoassay

    International Nuclear Information System (INIS)

    Umezawa, Sachiko; Yano, Hisako; Tanaka, Toshiaki; Hibi, Itsuo; Tsukimoto, Ichiro; Ishikawa, Eiji; Mouri, Yoshikazu; Murakami, Yoshiaki.

    1989-01-01

    Elective cranial irradiation in central nervous leukemia leads to a long term survival; however, the influence upon the hypothalamus and hypophysis remains uncertain. Therefore, changes in SD scores of height and urinary growth hormone (U-GH) levels were determined in 23 leukemic patients previously treated with cranial elective irradition of 18 or 24 Gy, whose ages ranged from 4 to 16 years. Decreased SD scores of height was observed in 9 (90%) of 10 patients in whom treatment has been continuing (within 5 years after the onset) and in 6 (50%) of 12 patients in whom treatment had been completed (5 years or more after the onset). The level of U-GH was significantly decreased in leukemic patients during complete remission than in healthy children. U-HG levels were independent of radiation doses. In evaluable 14 patients, the blood concentration of somatomedin C (SM-C) was within the normal range. Although there was a discrepancy between U-CH and SM-C levels, further follow-up of these leukemic patients is required. (N.K.)

  11. Intellectual Properties Rights-A strong determinant of economic growth in agriculture

    Directory of Open Access Journals (Sweden)

    Manju Chaudhary

    2010-03-01

    Full Text Available

    In the past few decades the subject of intellectual property rights (IPRs has occupied center stage in debates about globalization, economic development and poverty elimination. This study concerns the strengthening of IPRs in the plant breeding industry and its effect on agriculture in India. In India, most of the population relies on agriculture for its livelihood. India is self-sufficient in wheat and paddy, but deficient in other agricultural products. Patents are good indicators of research and development output. Patent analysis makes it possible to map out the trend of technological change and life cycle of a technology – growth, development, maturity and decline. Patent information and patent statistical analysis have been used for examining present, technological status and to forecast future trends. One can determine the directions of corporate R&D and market interests by analyzing patent data. The present study is an attempt to analyze patents granted in India in the field of agriculture and importance of biotechnology-based innovations in agriculture

  12. New methods for determination of microbial adherence and colonization to bio material surface pre and post-irradiation treatment in cancer patients

    International Nuclear Information System (INIS)

    Shehata, M.M.K.K.

    2007-01-01

    Biomaterials are being used with increasing frequency in medical fields in the saving of patients' lives and enhancing the quality of life for many others.Colonization of biomaterials by some pathogenic microorganisms depends on their ability to grow and adhere to the solid surface which then allows microorganisms to from bio films in which they are protected from host defense mechanisms and antimicrobial chemotherapy. Adherence and colonization followed by biofilm formation has been implicated as a potential virulence factor of some pathogenic strains responsible for catheter related infections in immuno-compromised cancer patients. Adherence assay and quantitation of bio films of microorganisms isolated and identified from catheter associated urinary tract infections from bladder cancer patients was performed by spectrophotometric method, hydrophobicities of some tested strains were also evaluated by adhesion to p-xylene, MICs of various antibiotics for isolated strains in conjunction with plasmid profiles and algD gene responsible for biofilm formation of selected strains were determined before and after in-vitro exposure to test dose of 24.14 Gy gamma radiation in studying the role of radiotherapy on the microorganisms and their virulence and also enable the design for new approaches to the prevention of serious microbial infections by interfering with adhesion process

  13. Molecular imprinted hydrogel polymer (MIHP) as microbial immobilization media in artificial produced water treatment

    Science.gov (United States)

    Kardena, E.; Ridhati, S. L.; Helmy, Q.

    2018-01-01

    Produced water generated during oil and gas exploration and drilling, consists of many chemicals which used in drilling process. The production of produced water is over three fold of the oil production. The water-cut has increased over time and continues to do so because the fraction of oil in the reservoir decreases and it is more difficult to get the oil out from an old oil-field. It therefore requires more sea water to be injected in order to force the oil out; hence more produced water is generated. Produced water can pollute the environment if it is not treated properly. In this research, produced water will be treated biologically using bacterial consortium which is isolated from petroleum processing facility with Molecular Imprinted Hydrogel Polymer (MIHP) for microbial immobilization media. Microbial growth rate is determined by measuring the MLVSS and hydrogel mass, also by SEM-EDS analysis. SEM-EDS analysis is an analysis to evidence the presence of microbe trapped in hydrogel, and also to determine the types and weight of the molecules of hydrogel. From this research, suspended microbial growth rate was found at 0.1532/days and attached microbial growth rate was 0.3322/days. Furthermore, based on SEM analysis, microbe is entrapped inside the hydrogel. Effectiveness of microbial degradation activity was determined by measuring organic materials as COD. Based on COD measurement, degradation rate of organic materials in wastewater is 0.3089/days, with maximum COD removal efficiency of 76.67%.

  14. Determining bank effects on economic growth: An artificial neural network analysis

    OpenAIRE

    Alex Senajon

    2016-01-01

    This study characterized the influence of the banking industry’s influence on the growth of the economy. A neural network using the Multilayer Perception was used to define functions of Universal Bank, Cooperative Bank, and Thrift Bank as predictors of Gross Domestic Product growth. Using data series from 2003- 2013, it was found that Universal banks have been growing tremendously taking huge shares of growth compared to the other two bank types. Meantime, the Gross Domestic Product was fo...

  15. Determinants of Renewable Energy Resources and Their Relationship Between Economic Growth: The Case of Developing Countries

    OpenAIRE

    Serkan Çınar; Mine Yılmazer

    2015-01-01

    Literature on the relationship between energy consumption and economic growth is based on two different approaches that are supply-side and demand-side. The impact of renewable and non-renewable energy consumption on economic growth is investigated with traditional production function on supply-side approach. The relationship between renewable energy consumption, economic growth, CO2 and energy prices is analyzed on demand-side approach. In this study, the impact of renewable resources on eco...

  16. Life history and spatial determinants of somatic growth dynamics in Komodo dragon populations

    OpenAIRE

    Laver, Rj; Purwandana, D; Ariefiandy, A; Imansyah, J; Forsyth, D; Ciofi, C; Jessop, Ts

    2012-01-01

    Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture st...

  17. Determining Optimal Degree of Soil Compaction for Balancing Mechanical Stability and Plant Growth Capacity

    National Research Council Canada - National Science Library

    Goldsmith, Wendi

    2001-01-01

    .... Agronomists, on the other hand, recommend minimal soil compaction because compacted soils are widely understood to impede the growth and development of crops, forests, and native plant communities...

  18. Determinants of impaired growth among hospitalized children: a case-control study

    Directory of Open Access Journals (Sweden)

    Marilia de Carvalho Lima

    case in this study, in which other variables had greater impact on child growth. CONCLUSIONS: In view of the multiple causes of malnutrition, the interrelationship among its determinants should be taken into account when adopting strategies for its reduction and prevention.

  19. The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

    Science.gov (United States)

    Gorbacheva, M.

    2012-04-01

    M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for

  20. A validation framework for microbial forensic methods based on statistical pattern recognition

    Energy Technology Data Exchange (ETDEWEB)

    Velsko, S P

    2007-11-12

    This report discusses a general approach to validating microbial forensic methods that attempt to simultaneously distinguish among many hypotheses concerning the manufacture of a questioned biological agent sample. It focuses on the concrete example of determining growth medium from chemical or molecular properties of a bacterial agent to illustrate the concepts involved.

  1. Microbial stability of worm castings and sugarcane filter mud compost blended with biochar

    Science.gov (United States)

    Organic amendments such as worm castings and filter mud compost can provide nutrient rich substrates for enhanced plant growth. Physico-chemical and microbial stability of these substrates might be enhanced with the addition of biochar. A series of experiments was carried out to determine the stab...

  2. Investigations to determine whether viable microorganisms are required during intestinal lactose hydrolysis of fermented milk products by microbial ß-galactosidase using gnotobiotic Göttingen minipigs

    OpenAIRE

    Winchenbach, Andrea

    2010-01-01

    The most common reason worldwide for the indigestibility of milk is the lack of ß-galactosidases in the small intestine, leading to the malabsorbtion of lactose. Fermented dairy products are very often much better tolerated than raw (not fermented) milk, because of the microbial ß-galactosidases they contain. The aim of this thesis was to elucidate the question as to weather lactose hydrolysis in the small intestine requires the presence of living bacteria (with their microbial ß-galac...

  3. [Chromatographic mass spectrometric determination of low-molecular-weight aromatic compounds of microbial origin in the serum from patients with sepsis].

    Science.gov (United States)

    Beloborodova, N V; Arkhipova, A S; Beloborodov, D M; Boĭko, N B; Mel'ko, A I; Olenin, A Iu

    2006-02-01

    The investigation quantitatively determined the content of low-molecular-weight aromatic compounds of microbial origin in the sera of 34 individuals by chromatographic mass spectrometry. An "Agilent Technogies 6890N" gas chromatograph with a 5973 mass selective detector was applied; chromatographic separation of components was effected on an Hp-5MS quartz capillary column. Aromatic small molecules originating from microbes (SMOM) were determined in the sera of 7 patients with sepsis. The diagnosis of sepsis was documented by the presence of the systemic inflammation syndrome and by that of bacteriemia and/or artificial ventilation-associated pneumonia along with the level of procalcitonin of higher than 10 ng/ml. The levels of aromatic SMOM were compared in 10 healthy donors, 8 preoperative cardiosurgical patients, and 9 patients with different abnormalities without sepsis treated in an intensive care unit (ICU). Serum phenylacetic and 3-phenylpropionic acids were found to be prevalent in the healthy donors and postoperative cardiosurgical patients. In ICU patients with different complications without sepsis, more than half the compounds under study were undetectable, the others were found in very low concentrations, which may be accounted for by antibiotic therapy. At the same time, almost the whole spectrum of the test compounds (other than 3-phenylpropionic acid) with the highest concentrations of 3-phenyllactic, p-hydroxyphenylacetic, 3-(p-hydroxyphenyl)lactic and 2-hydroxybutanic acids, was detectable in septic patients receiving a more intensive therapy. The differences were statistically significant (by the Mann-Whitney U-test; p < 0.05). By taking into account the potentially high biological activity of the test compounds, studies are to be continued in this area.

  4. Age and growth determination by skeletochronology in loggerhead sea turtles (Caretta caretta from the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Paolo Casale

    2011-03-01

    Full Text Available Skeletochronology was applied to humerus bones to assess the age and growth rates of loggerhead sea turtles (Caretta caretta in the Mediterranean Sea. Fifty-five dead turtles with curved carapace lengths (CCL ranging from 24 to 86.5 cm were collected from the central Mediterranean. Sections of humeri were histologically processed to analyze annual growth marks. Two approaches were used to estimate the somatic growth in the form of a von Bertalanffy growth function. The first approach was based on calculating the total number of growth marks, which corresponds to the age of turtles at death. The second approach estimates the carapace length at old growth marks in order to provide the growth rate of each turtle. The observed individual growth rates ranged from 1.4 to 6.2 cm yr–1, and showed both elevated inter- and intra-individual variability possibly related to the environmental variability experienced by turtles during their lifetime. Both approaches gave similar results and suggest that Mediterranean loggerhead turtles take 14.9 to 28.5 years to reach a CCL of 66.5 to 84.7 cm. This size corresponds to the average size of nesting females found in the most important Mediterranean nesting sites and can be considered the approximate size at maturity.

  5. Using interval maxima regression (IMR) to determine environmental optima controlling Microcystis spp. growth in Lake Taihu.

    Science.gov (United States)

    Li, Ming; Peng, Qiang; Xiao, Man

    2016-01-01

    Fortnightly investigations at 12 sampling sites in Meiliang Bay and Gonghu Bay of Lake Taihu (China) were carried out from June to early November 2010. The relationship between abiotic factors and cell density of different Microcystis species was analyzed using the interval maxima regression (IMR) to determine the optimum temperature and nutrient concentrations for growth of different Microcystis species. Our results showed that cell density of all the Microcystis species increased along with the increase of water temperature, but Microcystis aeruginosa adapted to a wide range of temperatures. The optimum total dissolved nitrogen concentrations for M. aeruginosa, Microcystis wesenbergii, Microcystis ichthyoblabe, and unidentified Microcystis were 3.7, 2.0, 2.4, and 1.9 mg L(-1), respectively. The optimum total dissolved phosphorus concentrations for different species were M. wesenbergii (0.27 mg L(-1)) > M. aeruginosa (0.1 mg L(-1)) > M. ichthyoblabe (0.06 mg L(-1)) ≈ unidentified Microcystis, and the iron (Fe(3+)) concentrations were M. wesenbergii (0.73 mg L(-1)) > M. aeruginosa (0.42 mg L(-1)) > M. ichthyoblabe (0.35 mg L(-1)) > unidentified Microcystis (0.09 mg L(-1)). The above results suggest that if phosphorus concentration was reduced to 0.06 mg L(-1) or/and iron concentration was reduced to 0.35 mg L(-1) in Lake Taihu, the large colonial M. wesenbergii and M. aeruginosa would be replaced by small colonial M. ichthyoblabe and unidentified Microcystis. Thereafter, the intensity and frequency of the occurrence of Microcystis blooms would be reduced by changing Microcystis species composition.

  6. Phenology, growth, and fecundity as determinants of distribution in closely related nonnative taxa

    Science.gov (United States)

    Marushia, Robin G.; Brooks, Matthew L.; Holt, Jodie S.

    2012-01-01

    Invasive species researchers often ask: Why do some species invade certain habitats while others do not? Ecological theories predict that taxonomically related species may invade similar habitats, but some related species exhibit contrasting invasion patterns. Brassica nigra, Brassica tournefortii, and Hirschfeldia incana are dominant, closely related nonnative species that have overlapping, but dissimilar, distributions. Brassica tournefortii is rapidly spreading in warm deserts of the southwestern United States, whereas B. nigra and H. incana are primarily limited to semiarid and mesic regions. We compared traits of B. tournefortii that might confer invasiveness in deserts with those of related species that have not invaded desert ecosystems. Brassica tournefortii, B. nigra and H. incana were compared in controlled experiments conducted outdoors in a mesic site (Riverside, CA) and a desert site (Blue Diamond, NV), and in greenhouses, over 3 yr. Desert and mesic B. tournefortii populations were also compared to determine whether locally adapted ecotypes contribute to desert invasion. Experimental variables included common garden sites and soil water availability. Response variables included emergence, growth, phenology, and reproduction. There was no evidence for B. tournefortii ecotypes, but B. tournefortii had a more rapid phenology than B. nigra or H. incana. Brassica tournefortii was less affected by site and water availability than B. nigra and H. incana, but was smaller and less fecund regardless of experimental conditions. Rapid phenology allows B. tournefortii to reproduce consistently under variable, stressful conditions such as those found in Southwestern deserts. Although more successful in milder, mesic ecosystems, B. nigra and H. incana may be limited by their ability to reproduce under desert conditions. Rapid phenology and drought response partition invasion patterns of nonnative mustards along a gradient of aridity in the southwestern United States

  7. MRI of growth hormone-secreting pituitary adenomas: factors determining pretreatment hormone levels

    Energy Technology Data Exchange (ETDEWEB)

    Saeki, N.; Iuchi, T.; Eda, M.; Yamaura, A. [Dept. of Neurological Surgery, Chiba University School of Medicine (Japan); Isono, S. [Dept. of Neurological Surgery, Anesthesiology, Chiba University School of Medicine, Chiba (Japan)

    1999-10-01

    Preoperative serum growth hormone (GH) level is one of the most important determinants of outcome. Our aim was to assess MRI findings which may correlate with pretreatment GH levels in GH-secreting adenomas. We retrospectively studied 29 patients with acromegaly caused by a pituitary adenoma. Tumor size (height, width, thickness and volume), suprasellar extension, sphenoid or cavernous sinus invasion, signal intensity and contrast enhancement were studied. Linear regression analysis or Fisher's exact probability test was used for statistical analysis. Factors related to high GH levels were the maximum dimension of the tumour (r = 0.496, P < 0.01), its volume (r = 0.439, P < 0.05), spenoid sinus invasion (P < 0.01) and intracavernous carotid artery encasement (P < 0.01). The other items were not related to serum GH levels. Since we believe surgery is the first choice of treatment and the cavernous sinus is difficult of access with a conventional surgical approach, preoperative assessment of invasion into the cavernous sinus is critical for predicting the surgical outcome. Low GH levels (5-50 ng/ml) were found with tumours medial to the intercarotid line and high levels (more than 101 ng/ml) with invasive tumours with carotid artery encasement. Variable GH levels were noted with tumours extending beyond the intercarotid line. Because functioning adenomas invading the cavernous sinus tend to have markedly high hormone levels, and only patients with carotid artery encasement showed markedly elevated GH levels, we believe carotid artery encasement a reliable MRI indicator of cavernous sinus invasion. (orig.)

  8. Trichoderma-Induced Acidification Is an Early Trigger for Changes in Arabidopsis Root Growth and Determines Fungal Phytostimulation

    Science.gov (United States)

    Pelagio-Flores, Ramón; Esparza-Reynoso, Saraí; Garnica-Vergara, Amira; López-Bucio, José; Herrera-Estrella, Alfredo

    2017-01-01

    Trichoderma spp. are common rhizosphere inhabitants widely used as biological control agents and their role as plant growth promoting fungi has been established. Although soil pH influences several fungal and plant functional traits such as growth and nutrition, little is known about its influence in rhizospheric or mutualistic interactions. The role of pH in the Trichoderma–Arabidopsis interaction was studied by determining primary root growth and lateral root formation, root meristem status and cell viability, quiescent center (QC) integrity, and auxin inducible gene expression. Primary root growth phenotypes in wild type seedlings and STOP1 mutants allowed identification of a putative root pH sensing pathway likely operating in plant–fungus recognition. Acidification by Trichoderma induced auxin redistribution within Arabidopsis columella root cap cells, causing root tip bending and growth inhibition. Root growth stoppage correlated with decreased cell division and with the loss of QC integrity and cell viability, which were reversed by buffering the medium. In addition, stop1, an Arabidopsis mutant sensitive to low pH, was oversensitive to T. atroviride primary root growth repression, providing genetic evidence that a pH root sensing mechanism reprograms root architecture during the interaction. Our results indicate that root sensing of pH mediates the interaction of Trichoderma with plants. PMID:28567051

  9. Growth and histamine formation of Morganella morganii in determining the safety and quality of inoculated and uninoculated bluefish (Pomatomus saltatrix).

    Science.gov (United States)

    Lorca, T A; Gingerich, T M; Pierson, M D; Flick, G J; Hackney, C R; Sumner, S S

    2001-12-01

    The objective of this study was to determine the effect of normal microflora and Morganella morganii on histamine formation and olfactory acceptability in raw bluefish under controlled storage conditions. Fillets inoculated with and without M. morganii were stored at 5, 10, and 15 degrees C for 7 days. Microbial isolates from surface swabs were identified and screened for histidine decarboxylase activity. Olfactory acceptance was performed by an informal sensory panel. Histamine levels were quantified using high-performance liquid chromatography and fluorescence detection. While olfactory acceptance decreased, histamine concentration and bacterial counts increased. Storage temperature had a significant effect on histamine levels, bacterial counts, and olfactory acceptance of the bluefish. Inoculation with M. morganii had a positive significant effect on histamine formation for bluefish held at 10 and 15 degrees C (P bluefish.

  10. Effect of dietary supplementation with Rhizopus oryzae or Chrysonilia crassa on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

    Directory of Open Access Journals (Sweden)

    S. Sugiharto

    2017-09-01

    Full Text Available Dietary supplementation of additives has recently been part of strategies to deal with the detrimental effects of heat stress (HS on the performance and carcass traits in broiler chicks. This study aimed to investigate the effect of dietary supplementation with the fungi Rhizopus oryzae or Chrysonilia crassa on growth, blood profile, intestinal microbial population and carcass traits in broiler chicks subjected to HS. R. oryzae and C. crassa are filamentous fungi isolated from the ileum of indigenous Indonesian chickens which exhibited probiotic and antioxidant properties. Two hundred and forty 21-day-old male broiler chicks were randomly allotted into six groups, including birds reared under normal temperature (28 ± 2 °C (CONT, birds reared under HS conditions (35 ± 2 °C (HS-CONT, birds reared under HS and provided with commercial anti-stress formula (HS-VIT, birds reared under HS and provided with R. oryzae (HS-RO, birds reared under HS and provided with C. crassa (HS-CC and birds reared under HS and provided with rice bran (HS-RB. Body weight gain was highest (P < 0. 01 and lowest (P < 0. 01 in CONT and HS-CONT birds, respectively. The heart was heavier (P < 0. 05 in CONT than in HS-CONT and HS-VIT birds. CONT birds had heavier duodenum (P < 0. 05 and jejunum (P < 0. 01 than other birds. Eosinophils was higher (P < 0. 05 in HS-CC than in other birds. Low-density lipoprotein (LDL was higher (P < 0. 05 in HS-CONT than in CONT, HS-VIT and HS-CC birds. Total triglyceride was highest (P < 0. 05 and lowest (P < 0. 05 in HS-RB and HS-RO birds, respectively. Alanine aminotransferase (ALT was higher (P < 0. 05 in HS-CONT than in other HS birds. Total protein was lowest and highest (P < 0. 05 in CONT and HS-CONT birds, respectively. Albumin was higher (P < 0. 05 in HS-CONT and HS-VIT than in HS-RO birds. Globulin was lower (P < 0. 05 in CONT than in HS

  11. Global microbialization of coral reefs.

    Science.gov (United States)

    Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

    2016-04-25

    Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

  12. Microbial glycoproteomics

    DEFF Research Database (Denmark)

    Halim, Adnan; Anonsen, Jan Haug

    2017-01-01

    Mass spectrometry-based "-omics" technologies are important tools for global and detailed mapping of post-translational modifications. Protein glycosylation is an abundant and important post translational modification widespread throughout all domains of life. Characterization of glycoproteins...... and research in this area is rapidly accelerating. Here, we review recent developments in glycoproteomic technologies with a special focus on microbial protein glycosylation....

  13. Habitat structure and body size distributions: Cross-ecosystem comparison for taxa with determinate and indeterminate growth

    Science.gov (United States)

    Nash, Kirsty L.; Allen, Craig R.; Barichievy, Chris; Nystrom, Magnus; Sundstrom, Shana M.; Graham, Nicholas A.J.

    2014-01-01

    Habitat structure across multiple spatial and temporal scales has been proposed as a key driver of body size distributions for associated communities. Thus, understanding the relationship between habitat and body size is fundamental to developing predictions regarding the influence of habitat change on animal communities. Much of the work assessing the relationship between habitat structure and body size distributions has focused on terrestrial taxa with determinate growth, and has primarily analysed discontinuities (gaps) in the distribution of species mean sizes (species size relationships or SSRs). The suitability of this approach for taxa with indeterminate growth has yet to be determined. We provide a cross-ecosystem comparison of bird (determinate growth) and fish (indeterminate growth) body mass distributions using four independent data sets. We evaluate three size distribution indices: SSRs, species size–density relationships (SSDRs) and individual size–density relationships (ISDRs), and two types of analysis: looking for either discontinuities or abundance patterns and multi-modality in the distributions. To assess the respective suitability of these three indices and two analytical approaches for understanding habitat–size relationships in different ecosystems, we compare their ability to differentiate bird or fish communities found within contrasting habitat conditions. All three indices of body size distribution are useful for examining the relationship between cross-scale patterns of habitat structure and size for species with determinate growth, such as birds. In contrast, for species with indeterminate growth such as fish, the relationship between habitat structure and body size may be masked when using mean summary metrics, and thus individual-level data (ISDRs) are more useful. Furthermore, ISDRs, which have traditionally been used to study aquatic systems, present a potentially useful common currency for comparing body size distributions

  14. APPLICATION OF ELASTICITY ANALYSES AND PERTURBATION SIMULATIONS IN DETERMINING STRESSOR IMPACTS ON POPULATION GROWTH RATE AND EXTINCTION RISK

    Science.gov (United States)

    Population structure and life history strategies are determinants of how populations respond to stressor-induced impairments in individual-level responses, but a consistent and holistic analysis has not been reported. Effects on population growth rate were modeled using five theo...

  15. A Latent Class Growth Analysis of School Bullying and Its Social Context: The Self-Determination Theory Perspective

    Science.gov (United States)

    Lam, Shui-fong; Law, Wilbert; Chan, Chi-Keung; Wong, Bernard P. H.; Zhang, Xiao

    2015-01-01

    The contribution of social context to school bullying was examined from the self-determination theory perspective in this longitudinal study of 536 adolescents from 3 secondary schools in Hong Kong. Latent class growth analysis of the student-reported data at 5 time points from grade 7 to grade 9 identified 4 groups of students: bullies (9.8%),…

  16. Dynamics of culturable soil microbial communities during ...

    African Journals Online (AJOL)

    Ecological zones impacted significantly (P < 0.05) on bacterial proliferation, but not on fungal growth. Sampling period significantly (P < 0.05) affected microbial density and the semi-arid agroecozone was more supportive of microbial proliferation than the arid zone. A total of nine predominant fungal species belonging to ...

  17. Thermosensitivity of growth is determined by chaperone-mediated proteome reallocation

    DEFF Research Database (Denmark)

    Chen, Ke; Gao, Ye; Mih, Nathan

    2017-01-01

    Maintenance of a properly folded proteome is critical for bacterial survival at notably different growth temperatures. Understanding the molecular basis of thermoadaptation has progressed in two main directions, the sequence and structural basis of protein thermostability and the mechanistic prin...

  18. Crystallite growth in nanocrystalline tungsten; rate determining mechanism and the role of contaminations

    International Nuclear Information System (INIS)

    Hegedűs, Zoltán; Meka, Sai Ramudu; Mittemeijer, Eric J.

    2016-01-01

    The thermal stability of nanocrystalline tungsten was investigated by tracing the evolution of the microstructure as a function of (isothermal) annealing time at different temperatures (800−875 °C). To this end especially in situ X-ray diffraction and transmission electron microscopy methods were applied to ball milled tungsten powder. Initially the dislocation density and the crystallite/domain size decreased and increased rapidly, respectively. Upon prolonged annealing the crystallite growth rate decelerated and even became nil: a saturation crystallite size, increasing with increasing annealing temperature, was attained. Application of all available isothermal growth models to the experimental data resulted in very low values for the activation energy (60−120 kJ/mol) indicating that recovery of the deformed microstructure is the dominantly occurring process, leading to pronounced crystallite/domain growth. The effect on the growth kinetics of different levels of contaminations, which exert a drag force on the moving boundaries, was also investigated.

  19. Species-specific effects of epigeic earthworms on microbial community structure during first stages of decomposition of organic matter.

    Science.gov (United States)

    Gómez-Brandón, María; Lores, Marta; Domínguez, Jorge

    2012-01-01

    Epigeic earthworms are key organisms in organic matter decomposition because of the interactions they establish with microorganisms. The earthworm species and the quality and/or substrate availability are expected to be major factors influencing the outcome of these interactions. Here we tested whether and to what extent the epigeic earthworms Eisenia andrei, Eisenia fetida and Perionyx excavatus, widely used in vermicomposting, are capable of altering the microbiological properties of fresh organic matter in the short-term. We also questioned if the earthworm-induced modifications to the microbial communities are dependent on the type of substrate ingested. To address these questions we determined the microbial community structure (phospholipid fatty acid profiles) and microbial activity (basal respiration and microbial growth rates) of three types of animal manure (cow, horse and rabbit) that differed in microbial composition, after being processed by each species of earthworm for one month. No differences were found between earthworm-worked samples with regards to microbial community structure, irrespective of type of manure, which suggests the existence of a bottleneck effect of worm digestion on microbial populations of the original material consumed. Moreover, in mesocosms containing cow manure the presence of E. andrei resulted not only in a decrease in bacterial and fungal biomass, but also in a reduced bacterial growth rate and total microbial activity, while no such reduction was found with E. fetida and P. excavatus. Our results point to the species of earthworm with its associated gut microbiota as a strong determinant of the process shaping the structure of microbial communities in the short-term. This must nonetheless be weighed against the fact that further knowledge is necessary to evaluate whether the changes in the composition of microbiota in response to the earthworm species is accompanied by a change in the microbial community diversity and

  20. Species-specific effects of epigeic earthworms on microbial community structure during first stages of decomposition of organic matter.

    Directory of Open Access Journals (Sweden)

    María Gómez-Brandón

    Full Text Available Epigeic earthworms are key organisms in organic matter decomposition because of the interactions they establish with microorganisms. The earthworm species and the quality and/or substrate availability are expected to be major factors influencing the outcome of these interactions. Here we tested whether and to what extent the epigeic earthworms Eisenia andrei, Eisenia fetida and Perionyx excavatus, widely used in vermicomposting, are capable of altering the microbiological properties of fresh organic matter in the short-term. We also questioned if the earthworm-induced modifications to the microbial communities are dependent on the type of substrate ingested.To address these questions we determined the microbial community structure (phospholipid fatty acid profiles and microbial activity (basal respiration and microbial growth rates of three types of animal manure (cow, horse and rabbit that differed in microbial composition, after being processed by each species of earthworm for one month. No differences were found between earthworm-worked samples with regards to microbial community structure, irrespective of type of manure, which suggests the existence of a bottleneck effect of worm digestion on microbial populations of the original material consumed. Moreover, in mesocosms containing cow manure the presence of E. andrei resulted not only in a decrease in bacterial and fungal biomass, but also in a reduced bacterial growth rate and total microbial activity, while no such reduction was found with E. fetida and P. excavatus.Our results point to the species of earthworm with its associated gut microbiota as a strong determinant of the process shaping the structure of microbial communities in the short-term. This must nonetheless be weighed against the fact that further knowledge is necessary to evaluate whether the changes in the composition of microbiota in response to the earthworm species is accompanied by a change in the microbial community

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

    Science.gov (United States)

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

    2009-02-01

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

  2. Microbial reduction of uranium using cellulosic substrates

    International Nuclear Information System (INIS)

    Thombre, M.S.; Thomson, B.M.; Barton, L.L.

    1996-01-01

    Previous work at the University of New Mexico and elsewhere has shown that sulfate-reducing bacteria are capable of reducing uranium from the soluble +6 oxidation state to the insoluble +4 oxidation state. This chemistry forms the basis of a proposed ground water remediation strategy in which microbial reduction would be used to immobilize soluble uranium. One such system would consist of a subsurface permeable barrier which would stimulate microbial growth resulting in the reduction of sulfate and nitrate and immobilization of metals while permitting the unhindered flow of ground water through it. This research investigated some of the engineering considerations associated with a microbial reducing barrier such as identifying an appropriate biological substrate, estimating the rate of substrate utilization, and identifying the final fate of the contaminants concentrated in the barrier matrix. The performance of batch reactors and column systems that treated simulated plume water was evaluated using cellulose, wheat straw, alfalfa hay, sawdust, and soluble starch as substrates. The concentrations of sulfate, nitrate, and U(VI) were monitored over time. Precipitates from each system were collected, and the precipitated U(IV) was determined to be crystalline UO 2(s) by x-ray diffraction. The results of this study support the proposed use of cellulosic substrates as candidate barrier materials

  3. Determining bank effects on economic growth: An artificial neural network analysis

    Directory of Open Access Journals (Sweden)

    Alex Senajon

    2016-01-01

    Full Text Available This study characterized the influence of the banking industry’s influence on the growth of the economy. A neural network using the Multilayer Perception was used to define functions of Universal Bank, Cooperative Bank, and Thrift Bank as predictors of Gross Domestic Product growth. Using data series from 2003- 2013, it was found that Universal banks have been growing tremendously taking huge shares of growth compared to the other two bank types. Meantime, the Gross Domestic Product was found to be steadily growing over the same period with a significant spike in 2004. In addition, neural network presents the contribution of the bank types on Gross Domestic Product, and found that the assets and capital of rural banks positively affect the Gross Domestic Product growth. As such, the sensitivity analysis of the Artificial Neural Network indicates Rural banks asset as the most important predictor of all the chosen variables followed by Universal bank capital. However, the capital of Thrift banks was found to show least contribution on the growth of the Gross Domestic Product.

  4. Modeling determinants of growth: evidence for a community-based target in height?

    Science.gov (United States)

    Aßmann, Christian; Hermanussen, Michael

    2013-07-01

    Human growth is traditionally envisaged as a target-seeking process regulated by genes, nutrition, health, and the state of an individual's social and economic environment; it is believed that under optimal physical conditions, an individual will achieve his or her full genetic potential. Using a panel data set on individual height increments, we suggest a statistical modeling approach that characterizes growth as first-order trend stationary and allows for controlling individual growth tempo via observable measures of individual maturity. A Bayesian framework and corresponding Markov-chain Monte Carlo techniques allowing for a conceptually stringent treatment of missing values are adapted for parameter estimation. The model provides evidence for the adjustment of the individual growth rate toward average height of the population. The increase in adult body height during the past 150 y has been explained by the steady improvement of living conditions that are now being considered to have reached an optimum in Western societies. The current investigation questions the notion that the traditional concept in the understanding of this target-seeking process is sufficient. We consider an additional regulator that possibly points at community-based target seeking in growth.

  5. Structure of the Mr 140,000 growth hormone-dependent insulin-like growth factor binding protein complex: Determination by reconstitution and affinity-labeling

    International Nuclear Information System (INIS)

    Baxter, R.C.; Martin, J.L.

    1989-01-01

    To determine the structure of the high molecular weight, growth hormone-dependent complex between the insulin-like growth factors (IGF-I and IGF-II) and their binding proteins in human serum, we have reconstituted the complex from its purified component proteins and analyzed it by gel electrophoresis and autoradiography after covalent cross-linking. The proteins tested in reconstitution mixtures were an acid-labile Mr 84,000-86,000 glycoprotein doublet (alpha subunit), an acid-stable Mr 47,000-53,000 glycoprotein doublet with IGF-binding activity (BP-53 or beta subunit), and IGF-I or IGF-II (gamma subunit). In incubations containing any one of the three subunits 125I-labeled and the other two unlabeled, identical 125I-labeled alpha-beta-gamma complexes of Mr 140,000 were formed. Minor bands of Mr 120,000 and 90,000 were also seen, thought to represent a partially deglycosylated form of the alpha-beta-gamma complex, and an alpha-gamma complex arising as a cross-linking artifact. When serum samples from subjects of various growth hormone status were affinity-labeled with IGF-II tracer, a growth hormone-dependent Mr 140,000 band was seen, corresponding to the reconstituted alpha-beta-gamma complex. Other growth hormone-dependent labeled bands, of Mr 90,000 (corresponding to alpha-gamma), Mr 55,000-60,000 (corresponding to labeled beta-subunit doublet), and smaller bands of Mr 38,000, 28,000, and 23,000-25,000 (corresponding to labeled beta-subunit degradation products), were also seen in the affinity-labeled serum samples and in the complex reconstituted from pure proteins. All were immunoprecipitable with an anti-BP-53 antiserum. We conclude that the growth hormone-dependent Mr 140,000 IGF-binding protein complex in human serum has three components: the alpha (acid-labile) subunit, the beta (binding) subunit, and the gamma (growth factor) subunit

  6. Soil microbial community response to land use and various soil ...

    African Journals Online (AJOL)

    Soil microbial community response to land use and various soil elements in a city landscape of north China. ... African Journal of Biotechnology ... Legumes played an important role in stimulating the growth and reproduction of various soil microbial populations, accordingly promoting the microbial catabolic activity.

  7. Genome-scale biological models for industrial microbial systems.

    Science.gov (United States)

    Xu, Nan; Ye, Chao; Liu, Liming

    2018-04-01

    The primary aims and challenges associated with microbial fermentation include achieving faster cell growth, higher productivity, and more robust production processes. Genome-scale biological models, predicting the formation of an interaction among genetic materials, enzymes, and metabolites, constitute a systematic and comprehensive platform to analyze and optimize the microbial growth and production of biological products. Genome-scale biological models can help optimize microbial growth-associated traits by simulating biomass formation, predicting growth rates, and identifying the requirements for cell growth. With regard to microbial product biosynthesis, genome-scale biological models can be used to design product biosynthetic pathways, accelerate production efficiency, and reduce metabolic side effects, leading to improved production performance. The present review discusses the development of microbial genome-scale biological models since their emergence and emphasizes their pertinent application in improving industrial microbial fermentation of biological products.

  8. 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.

  9. FDI AND FINANCIAL DEVELOPMENT AS DETERMINANTS OF ECONOMIC GROWTH FOR V4 COUNTRIES

    Directory of Open Access Journals (Sweden)

    Anastasiya Gural

    2017-09-01

    Full Text Available The purpose of the paper is to analyze the influence of foreign direct investment (FDI and financial development (qualitative and quantitative changes in the financial system and its components on the dynamics of economic growth in V4 countries. In modern conditions, the financial system is a transfer mechanism of the business cycle and therefore affects the structure and dynamics of foreign direct investment, and especially the efficiency of their assimilation. The subject of the survey is the financial development and the FDI flows impact on economic growth. Methodology. The survey is based on the evaluation of the equation, which is the Barro regression specification. This model helps to find out the impact of the volume and depth of financial system on the dynamics of economic growth. GDP growth per capita is used as an indicator of economic growth. The paper proposes modeling results for the group countries (Hungary, Poland, Slovak and Czech Republic. Static data have been used for the period from 1992 to 2016. Results. FDI has an important role in reforming and developing the national economies of the countries in Visegrad Group. However, today, there is a problem with the stability of FDI inflows and with the efficiency of their development, which negatively affects the dynamics of economic growth. An important factor is the insufficient level of national financial system development of the Visegrad countries. All countries of the group have bank-oriented financial systems that are heavily dependent on foreign capital. At the same time, governments pay particular attention to the stability of banking sectors and set high standards for their sustainability. This holds back the financial development of the national economies of the Visegrad Group. At the same time, regression models for all countries confirm the importance of financial development in economic growth. The most important for V4 countries is to increase the size of the

  10. Whey protein isolate/cellulose nanofibre/TiO2 nanoparticle/rosemary essential oil nanocomposite film: Its effect on microbial and sensory quality of lamb meat and growth of common foodborne pathogenic bacteria during refrigeration.

    Science.gov (United States)

    Alizadeh Sani, Mahmood; Ehsani, Ali; Hashemi, Mohammad

    2017-06-19

    The use of biodegradable nanocomposite films in active packaging is of great importance since they can have a controlled release of antimicrobial compounds. This study was conducted to evaluate the efficacy of whey protein isolate (WPI)/cellulose nanofibre (CNF) nanocomposite films containing 1.0% (w/w) titanium dioxide (TiO 2 ) and 2.0% (w/v) rosemary essential oil (REO) in preserving the microbial and sensory quality of lamb meat during the storage at 4±1°C. Initially, the best concentration of each compound to be added to the film was determined by micro-dilution and disc diffusion methods. The microbial and sensory properties of lamb meat were controlled in two groups (control and treatment) over 15days of storage. Then, the samples were analysed for total viable count (TVC), Pseudomonas spp. count, Enterobacteriaceae count, Lactic acid bacteria (LAB) count, inoculated Staphylococcus aureus count, Listeria monocytogenes count, and Escherichia coli O 157 :H 7 count. Microbial analysis and nine-point hedonic scale was applied for the sensory analysis. Results indicated that the use of nanocomposite films significantly reduced the bacterial counts of treatment group. Higher inhibition effect was observed on Gram-positive bacteria than on Gram-negative bacteria (Psensory evaluations also showed that the use of nanocomposite films significantly increased the shelf life of treated meat (15days) compared to the control meat (6days). Based on the results of this study, the edible nanocomposite films were effective in preserving the microbial and sensory qualities of lamb meat; therefore, this application is recommended in meat especially red meat. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Tunable diode laser absorption spectroscopy as method of choice for non-invasive and automated detection of microbial growth in media fills.

    Science.gov (United States)

    Brueckner, David; Roesti, David; Zuber, Ulrich; Sacher, Meik; Duncan, Derek; Krähenbühl, Stephan; Braissant, Olivier

    2017-05-15

    Tunable diode laser absorption spectroscopy (TDLAS) was evaluated on its potential to detect bacterial growth of contaminated media fill vials. The target was a replacement/ automation of the traditional visual media fill inspection. TDLAS was used to determine non-invasively O 2 and/or CO 2 changes in headspaces of such vials being induced by metabolically active microorganisms. Four different vial formats, 34 microorganisms (inoculation volume<10 cells) and two different media (TSB/FTM) were tested. Applying parallel CO 2 and O 2 headspace measurements all format-organism combinations were detected within <11 days reliably with reproducible results. False negatives were exclusively observed for samples that were intentionally breached with syringes of 0.3mm in diameter. Overall it was shown that TDLAS functionality for a replacement of the visual media fill inspection is given and that investing in further validation and implementation studies is valuable. Nevertheless, some small but vincible challenges remain to have this technology in practical use. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Variations in the Spatial Distribution of Areas of Economic Growth and Stagnation in Poland: Determinants and Consequences

    Directory of Open Access Journals (Sweden)

    Churski Paweł

    2014-06-01

    Full Text Available This study seeks to identify the spatial distribution of and changes in areas of economic growth and stagnation in Poland resulting from spatial differences in the process of the country’s socio-economic advancement. The research covered two spatial systems, NUTS 2 and NUTS 4, and embraced the following steps: (1 identification of the spatial distribution of areas of economic growth and stagnation, by region and subregion, and of its determinants; (2 analysis of variations in the spatial distribution of areas of economic growth and stagnation, by region and subregion, and of its consequences; and (3 conclusions from the development trajectories identified and recommendations for intervention measures to be taken under cohesion policy.

  13. Using random walk in models specified by stochastic differential equations to determine the best expression for the bacterial growth rate

    DEFF Research Database (Denmark)

    method allows us to develop a new expression for the growth rate. The method is based on the stochastic continuous-discrete time state-space model, with a continuous-time state equation (a stochastic differential equation, SDE) combined with a discrete-time measurement equation. In our study the SDE...... described by Kristensen et. al [2]. The resulting time series allows us graphically to inspect the functional dependence of the growth rate on the substrate content. From the method described above we find three new plausible expressions for μ(S). Therefore we apply the likelihood-ratio test to compare...... for the Monod expression. Thus, the method was applied to successfully determine a significant better expression for the substrate dependent growth expression, and we find the method generally applicable for model development. References [1] Kristensen NR, Madsen H, Jørgensen, SB (2004) A method for systematic...

  14. Preincubation of Penicillium commune conidia under modified atmosphere conditions: Influence on growth potential as determined by an impedimetric method

    DEFF Research Database (Denmark)

    Haasum, Iben; Nielsen, Per Væggemose

    1996-01-01

    The combined effect of preincubation time, relative humidity (r.h.), headspace carbon dioxide (CO2) and oxygen (O2) on subsequent growth potential of conidia from Penicillium commune was studied using Response Surface Modelling (RSM). Native conidia were preincubated under modified atmosphere...... conditions in sealed vials for 14, 35 and 56 d. Lag time and growth rates were determined using impedance microbiology on a Bactometer. Conidia survived and some swelling was observed during all experimental preincubation conditions. Regression analysis of the subsequent growth responses showed that relative...... humidity in the vials was the most significant factor affecting lag time of the conidia after preincubation for 14 and 35 d. Storage for 35 d extended lag times by 15 h when the level of r.h. was increased from 41% to 80%. After prolonged storage (56 d) r.h and CO2 levels elicited a significant effect...

  15. Social and environmental determinants of child health in Mongolia across years of rapid economic growth: 2000-2010.

    Science.gov (United States)

    Joshi, Nehal; Bolorhon, Bolormaa; Narula, Indermohan; Zhu, Shihua; Manaseki-Hollan, Semira

    2017-10-30

    To understand the effect of economic growth on health, we investigated the trend in socio-economic and regional determinants of child health in Mongolia. This Central Asian country had the fastest economic growth amongst low and middle-income countries (LMICs) from 2000 to 2010 and a healthcare system in transition. Data was from Mongolian multiple indicator cluster surveys (MICS) in 2000, 2005 and 2010. Child nutrition/growth was measured by height-for-age z-score (HAZ), weight-for-age z-score (WAZ), prevalence of stunted (HAZ economic and environmental health determinants on each outcome in each year; 2000, 2005 and 2010. T-tests were used to measure significant change in HAZ and WAZ over the decade. Overall, from 2000 to 2010, there was a significant improvement (p economic factors increased on both stunting and weight. In 2000, region was a significant determinant: children living in three provinces were significantly more likely to be stunted and less likely to be immunised than Ulaanbaatar, but this was not significant by 2010. By 2010, none of the factors were significant determinants of immunisation in children. In 2000, economic status had no effect on stunting (OR = 0.91; 95%CI:0.49,1.66), however by 2010, children in the poorest economic quintile were 4 times more likely to be stunted than the richest (OR = 0.24; 95% CI:0.13,0.45; p Economic growth in Mongolia from 2000 to 2010 resulted in an increase in the effect of social determinants of child health; whilst focused policy improved access to immunisation. Children with less educated mothers and lower household incomes should be targeted in interventions to reduce health inequity.

  16. Belowground uptake strategies: how fine-root traits determine tree growth

    NARCIS (Netherlands)

    Weemstra, Monique

    2017-01-01

    The growth of trees depends on photosynthetic carbon gain by the leaves, which in turn relies on water and nutrient acquisition by the fine roots. Because the availability of carbon, water and nutrients fluctuates, trees can adjust their leaf and fine-root functional traits to maintain their

  17. Determinants of Growth, Adiposity and Bone Mass in Early Life : The Generation R Study

    NARCIS (Netherlands)

    D.H.M. Heppe (Denise)

    2016-01-01

    markdownabstractAbstract Environmental influences during fetal life and early infancy have been suggested to influence body composition throughout the life-course. Especially poor fetal nutrition and fetal growth restriction have been designated important risk factors for gaining high fat mass

  18. Female Education as a Determinant of Economic Growth: The Case Study of Pakistan

    Science.gov (United States)

    Fatima, Goher

    2011-01-01

    The contribution of female education has been very important in the GDP growth of the country, but this very sector has been ignored by the Government. This paper focuses on the importance of female education and highlights its significance for national development. It also brings out some impediments, obstacles and barriers confronting female…

  19. Determinants of long-term growth : New results applying robust estimation and extreme bounds analysis

    NARCIS (Netherlands)

    Sturm, J.-E.; de Haan, J.

    2005-01-01

    Two important problems exist in cross-country growth studies: outliers and model uncertainty. Employing Sala-i-Martin's (1997a,b) data set, we first use robust estimation and analyze to what extent outliers influence OLS regressions. We then use both OLS and robust estimation techniques in applying

  20. Socio-Demographic Determinants of Economic Growth: Age-Structure, Preindustrial Heritage and Sociolinguistic Integration

    Science.gov (United States)

    Crenshaw, Edward; Robison, Kristopher

    2010-01-01

    This study establishes a socio-demographic theory of international development derived from selected classical and contemporary sociological theories. Four hypotheses are tested: (1. population growth's effect on development depends on age-structure; (2. historic population density (used here as an indicator of preindustrial social complexity)…

  1. Determinants of Human Capital Formation and Economic Growth of African Countries

    Science.gov (United States)

    Oketch, Moses O.

    2006-01-01

    Rapid economic growth and improving living standards have benefited almost all regions of the world since the industrial revolution. Africa stands out as one regional exception. While several factors such as civil wars and rampant corruption have been associated with poor economic performance of the African region in the international community,…

  2. Growth strategy, phylogeny and stoichiometry determine the allelopathic potential of native and non-native plants

    NARCIS (Netherlands)

    Grutters, Bart M.C.; Saccomanno, Benedetta; Gross, Elisabeth M.; Van de Waal, Dedmer B.; van Donk, Ellen; Bakker, Elisabeth S.

    2017-01-01

    Secondary compounds can contribute to the success of non-native plant species if they reduce damage by native herbivores or inhibit the growth of native plant competitors. However, there is opposing evidence on whether the secondary com- pounds of non-native plant species are stronger than those of

  3. Microbial Genomes Multiply

    Science.gov (United States)

    Doolittle, Russell F.

    2002-01-01

    The publication of the first complete sequence of a bacterial genome in 1995 was a signal event, underscored by the fact that the article has been cited more than 2,100 times during the intervening seven years. It was a marvelous technical achievement, made possible by automatic DNA-sequencing machines. The feat is the more impressive in that complete genome sequencing has now been adopted in many different laboratories around the world. Four years ago in these columns I examined the situation after a dozen microbial genomes had been completed. Now, with upwards of 60 microbial genome sequences determined and twice that many in progress, it seems reasonable to assess just what is being learned. Are new concepts emerging about how cells work? Have there been practical benefits in the fields of medicine and agriculture? Is it feasible to determine the genomic sequence of every bacterial species on Earth? The answers to these questions maybe Yes, Perhaps, and No, respectively.

  4. Crystal structure of the tyrosine kinase domain of the hepatocyte growth factor receptor c-Met and its complex with the microbial alkaloid K-252a

    OpenAIRE

    Schiering, Nikolaus; Knapp, Stefan; Marconi, Marina; Flocco, Maria M.; Cui, Jean; Perego, Rita; Rusconi, Luisa; Cristiani, Cinzia

    2003-01-01

    The protooncogene c-met codes for the hepatocyte growth factor receptor tyrosine kinase. Binding of its ligand, hepatocyte growth factor/scatter factor, stimulates receptor autophosphorylation, which leads to pleiotropic downstream signaling events in epithelial cells, including cell growth, motility, and invasion. These events are mediated by interaction of cytoplasmic effectors, generally through Src homology 2 (SH2) domains, with two phosphotyrosine-containing sequence motifs in the unique...

  5. Host specificity for bacterial, archaeal and fungal communities determined for high- and low-microbial abundance sponge species in two genera

    NARCIS (Netherlands)

    Mares, De Maryam Chaib; Sipkema, Detmer; Huang, Sixing; Bunk, Boyke; Overmann, Jörg; Elsas, van Jan Dirk

    2017-01-01

    Sponges are engaged in intimate symbioses with a diversity of microorganisms from all three domains of life, namely Bacteria, Archaea and Eukarya. Sponges have been well studied and categorized for their bacterial communities, some displaying a high microbial abundance (HMA), while others show

  6. Determination of microbial versus root-produced CO2 in an agricultural ecosystem by means of δ13CO2 measurements in soil air

    NARCIS (Netherlands)

    Schüßler, Wolfram; Neubert, Rolf; Levin, Ingeborg; Fischer, Natalie; Sonntag, Christian

    2000-01-01

    The amounts of microbial and root-respired CO2 in a maize/winter wheat agricultural system in south western Germany were investigated by measurements of the CO2 mixing ratio and the 13C/12C ratio in soil air. CO2 fluxes at the soil surface for the period of investigation (1993–1995) were also

  7. Água residuária de esgoto doméstico tratado na atividade microbiana do solo e crescimento da mamoneira Treated wastewater from domestic sewage on soil microbial activity and growth of castor bean

    Directory of Open Access Journals (Sweden)

    Karine da S. Simões

    2013-05-01

    Full Text Available Os resíduos de esgoto doméstico apresentam teores de macro e micro nutrientes suficientes para atender a uma grande parte das culturas. Além de ser uma alternativa viável para aumentar a disponibilidade hídrica é uma forma efetiva de controle de poluição e preservação do meio ambiente. Neste contexto, realizou-se um experimento para avaliar a influência da aplicação de diferentes diluições de água residuária proveniente de esgoto doméstico tratado, na atividade microbiana de um Latossolo Amarelo Distrocoeso do Recôncavo Baiano e no crescimento inicial de plantas de mamoneira anã MPB 01. Avaliaram-se a atividade microbiana do solo e as características de crescimento da planta: altura, diâmetro do colo, biomassa seca da parte aérea, biomassa seca da raiz e volume de raízes. De acordo com os resultados, o efluente de esgoto doméstico tratado sem diluição estimula a atividade microbiana do Latossolo Amarelo Distrocoeso e prejudica o crescimento inicial da mamoneira anã MPB 01.Wastewater from domestic sewage presents levels of macro and micro nutrients sufficient to support a large part of the crops. Besides being a viable alternative to increase water availability, it is an effective way to control pollution and preserve the environment. In this context, an experiment was carried out to evaluate the influence of applying different dilutions of treated wastewater from domestic sewage on the microbial activity of a distrophic cohesive yellow Latosol in the Recôncavo of Bahia. Its effect on early growth of dwarf castor bean plants MPB 01 were also evaluated. Soil microbial activity and growth characteristics such as plant height, stem diameter, shoot dry weight, root dry weight and root volume were evaluated. According to the results, the effluent of treated wastewater without dilution, stimulates microbial activity of distrophic cohesive yellow Latosol and impairs the early growth of dwarf castor bean MPB 01.

  8. Determination of the growth restriction factor and grain size for aluminum alloys by a quasi-binary equivalent method

    International Nuclear Information System (INIS)

    Mitrašinović, A.M.; Robles Hernández, F.C.

    2012-01-01

    Highlights: ► A new method to determine the growth restricting factor. (Q) is proposed ► The proposed method is highly accurate (R 2 = 0.99) and simple. ► A major novelty of this method is the determination of Q for non-dilute samples. ► The method proposed herein is based on quasi-binary phase diagrams and composition. ► This method can be easily implemented industrially or as a research tool. - Abstract: In the present research paper is suggested a new methodology to determine the growth restricting factor (Q) and grain size (GS) for various Al-alloys. The present method combines a thermodynamical component based on the liquidus behavior of each alloying element that is later incorporated into the well known growth restricting models for multi-component alloys. This approach that can be used to determine Q and/or GS based on the chemical composition and the slope of the liquidus temperature of any Al-alloy solidified in close to equilibrium conditions. This method can be modified further in order to assess the effect of cooling rate or thermomechanical processing on growth restricting factor and grain size. In the present paper is proposed a highly accurate (R 2 = 0.99) and validated model for Al–Si alloys, but it can be modified for any other Al–X alloying system. The present method can be used for alloys with relatively high solute content and due to the use of the thermodynamics of liquidus this system considers the poisoning effects of single and multi-component alloying elements.

  9. The maturing of microbial ecology.

    Science.gov (United States)

    Schmidt, Thomas M

    2006-09-01

    A.J. Kluyver and C.B. van Niel introduced many scientists to the exceptional metabolic capacity of microbes and their remarkable ability to adapt to changing environments in The Microbe's Contribution to Biology. Beyond providing an overview of the physiology and adaptability of microbes, the book outlined many of the basic principles for the emerging discipline of microbial ecology. While the study of pure cultures was highlighted, provided a unifying framework for understanding the vast metabolic potential of microbes and their roles in the global cycling of elements, extrapolation from pure cultures to natural environments has often been overshadowed by microbiologists inability to culture many of the microbes seen in natural environments. A combination of genomic approaches is now providing a culture-independent view of the microbial world, revealing a more diverse and dynamic community of microbes than originally anticipated. As methods for determining the diversity of microbial communities become increasingly accessible, a major challenge to microbial ecologists is to link the structure of natural microbial communities with their functions. This article presents several examples from studies of aquatic and terrestrial microbial communities in which culture and culture-independent methods are providing an enhanced appreciation for the microbe's contribution to the evolution and maintenance of life on Earth, and offers some thoughts about the graduate-level educational programs needed to enhance the maturing field of microbial ecology.

  10. Microbial electrode sensor for alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

    1979-10-01

    A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

  11. Regional Determinants of Efficiency Growth of Small and Medium-Sized Enterprises. Evidence from Poland

    Directory of Open Access Journals (Sweden)

    Teresa Łuczka

    2012-01-01

    Full Text Available SMEs sector plays a vital role in modern economies. Therefore, the interest in its functioning among economists is in fact quite natural. This article is a part of a current research on regional factors contributing to the development of enterprises in this category. The first section examines earlier studies in this field conducted globally and in Poland. According to them, many elements enable the SME’s development. It is not surprisingly that the specified set of pro-growth factors does not exists. Next section describes the results of the author’s own studies in the fields. These studies relate to regional factors contributing to the efficiency growth of micro, small and medium-sized enterprises in Poland. Data used in the study was collected from GUS[1] and EUROSTAT and encompassed 16 provinces for the years 2003-2008. The model prepared included 11 independent variables on labor force, social mobility, living standard and R&D policy. The authors would have gladly considered more than 11 explanatory variable, but the inaccessibility of such data made it impossible. In the next step, using GRETL software, equations of regression were defined. On this basis it was concluded that the most important factors contributing to efficiency growth of SMEs are the amount of spending on R&D and the level of wages.

  12. Uncertainty in population growth rates: determining confidence intervals from point estimates of parameters.

    Directory of Open Access Journals (Sweden)

    Eleanor S Devenish Nelson

    Full Text Available BACKGROUND: Demographic models are widely used in conservation and management, and their parameterisation often relies on data collected for other purposes. When underlying data lack clear indications of associated uncertainty, modellers often fail to account for that uncertainty in model outputs, such as estimates of population growth. METHODOLOGY/PRINCIPAL FINDINGS: We applied a likelihood approach to infer uncertainty retrospectively from point estimates of vital rates. Combining this with resampling techniques and projection modelling, we show that confidence intervals for population growth estimates are easy to derive. We used similar techniques to examine the effects of sample size on uncertainty. Our approach is illustrated using data on the red fox, Vulpes vulpes, a predator of ecological and cultural importance, and the most widespread extant terrestrial mammal. We show that uncertainty surrounding estimated population growth rates can be high, even for relatively well-studied populations. Halving that uncertainty typically requires a quadrupling of sampling effort. CONCLUSIONS/SIGNIFICANCE: Our results compel caution when comparing demographic trends between populations without accounting for uncertainty. Our methods will be widely applicable to demographic studies of many species.

  13. Carbon-14 labeling of phytoplankton carbon and chlorophyll a carbon: determination of specific growth rates

    International Nuclear Information System (INIS)

    Welschmeyer, N.A.; Lorenzen, C.J.

    1984-01-01

    The pattern of photosynthetic 14 C labeling over time is described for phytoplankton. The carbon-specific growth rate (d -1 ) is defined explicitly by changes in the specific activity (dpm μg -1 C) of the algae. For Skeletonema costatum, growing in axenic batch culture, the specific activities of both total cellular carbon and chlorophyll carbon increase at equal rates and the change in specific activity with time follows the predicted pattern. The specific activity of 14 C-labeled chlorophyll a was used to estimate phytoplankton growth rates and C:Chl ratios of field samples in Dabob Bay (Puget Sound), Washington. Growth rates decreased with depth and C:Chl ratios were higher for samples incubated under high light intensity. In several instances the C:Chl ratio increased from the beginning to the end of the incubation; this trend was most conspicuous near surface light intensities and for days of high total incident radiation. On these occasions, Chl a was actively 14 C labeled, yet little (or even negative) change was noted in the concentration of Chl a. These results suggest that some process (or processes) of chlorophyll degradation must be active at the same time that chlorophyll is being synthesized

  14. The role of repetitive thought in determining posttraumatic growth and distress following interpersonal trauma.

    Science.gov (United States)

    Allbaugh, Lucy Jane; Wright, Margaret O'Dougherty; Folger, Susan F

    2016-01-01

    Repetitive thought (RT) strategies have been linked to a range of negative outcomes following traumatic interpersonal events but are proposed to serve an adaptive function under particular circumstances. This study examined outcomes following RT within a transdiagnostic framework, and explored the potentially adaptive nature of trait-like and event-related RT. The centrality of a traumatic event to one's identity was explored as a context under which the adaptive nature of RT might change. Young adults with interpersonal violence experiences (N = 163) reported use of trait-like and event-related RT, centrality of the event, depressive, anxious, and posttraumatic stress symptoms (PTSS), posttraumatic depreciation and posttraumatic growth. Hierarchical multiple regression analyses were used to examine main and moderating effects of four types of RT and event centrality on outcome variables. Centrality positively predicted depressive symptoms and PTSS, depreciation, and growth. Brooding RT positively predicted all negative outcomes. Reflecting RT positively predicted anxious symptoms and PTSS and depreciation. Only deliberate RT positively predicted growth. Centrality did not moderate any examined relationships. Findings highlight the importance of addressing specific types of RT in interventions with survivors and of considering centrality as a robust contributor to outcomes following interpersonal violence.

  15. Selection of methanogenic microbial by gamma irradiation on improvement of unaerobic digestion efficiency on biogas formation

    International Nuclear Information System (INIS)

    M Yazid; Aris Bastianudin

    2011-01-01

    Selection of methanogenic microbial by gamma irradiation as an effort on improvement of efficiency process on biogas formation has been done. The objectives of this research is to obtain the methanogenic microbial isolate with high specific growth constant (μ), there for will be applicable for increasing the efficiency of biogas formation process. The microbial content sludge sample was taken from the digester tank conventional biogas installation located in Marangan village, Bokoharjo, Prambanan, Sleman and the sludge was irradiated using Co-60 gamma irradiator with varied dosage dose of 0-25 KGy. Microbial culture formation is conducted in growing media with 30% liquid rumen content in un-aerobe condition by addition of 80% H2 and 20% CO_2 gas mixture. Analysis of colony growth was performed by observation using long-wave ultraviolet rays (UV rays), while the microbial growth was by spectro-photometric analysis. Determination of gas methane product was done using gas chromatographic method. The result shown that 4 isolated methanogenic microbial (RB10, RB15, RB20 and RB25) that grown on 10-25 kGy gamma irradiation. The identification result shows that isolate RB10 and RB25 are belong to Methanobacterium genus, while isolate RB15 and RB20 are belong to Methanosarcina and Methanospirillum genus respectively. The specific growth constant (μ) values of the 4 bacterial isolates are in the range between 0.022 - 0.031. On the other hand, the efficiency of methane gas production for each isolates is in the range of 53.4%. - 67.6%. It can be concluded that isolate RB25 was the isolate with the highest specific growth constant (μ) value 0.031 and its efficiency of methane gas production was 67.6%. (author)

  16. Stabilization of red fruit-based smoothies by high-pressure processing. Part A. Effects on microbial growth, enzyme activity, antioxidant capacity and physical stability.

    Science.gov (United States)

    Hurtado, Adriana; Guàrdia, Maria Dolors; Picouet, Pierre; Jofré, Anna; Ros, José María; Bañón, Sancho

    2017-02-01

    Non-thermal pasteurization by high-pressure processing (HPP) is increasingly replacing thermal processing (TP) to maintain the properties of fresh fruit products. However, most of the research on HPP-fruit products only partially addresses fruit-pressure interaction, which limits its practical interest. The objective of this study was to assess the use of a mild HPP treatment to stabilize red fruit-based smoothies (microbial, enzymatic, oxidative and physical stability). HPP (350 MPa/10 °C/5 min) was slightly less effective than TP (85 °C/7 min) in inactivating microbes (mesophilic and psychrophilic bacteria, coliforms, yeasts and moulds) in smoothies kept at 4 °C for up to 28 days. The main limitation of using HPP was its low efficacy in inactivating oxidative (polyphenol oxidase and peroxidase) and hydrolytic (pectin methyl esterase) enzymes. Data on antioxidant status, colour parameters, browning index, transmittance, turbidity and viscosity confirmed that the HPP-smoothies have a greater tendency towards oxidation and clarification, which might lead to undesirable sensory and nutritional changes (see Part B). The microbial quality of smoothies was adequately controlled by mild HPP treatment without affecting their physical-chemical characteristics; however, oxidative and hydrolytic enzymes are highly pressure-resistant, which suggests that additional strategies should be used to stabilize smoothies. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

    The long term safety and integrity of radioactive waste disposal sites proposed for use by Ontario Hydro may be affected by the release of radioactive gases. Microbes mediate the primary pathways of waste degradation and hence an assessment of their potential to produce gaseous end products from the breakdown of low level waste was performed. Due to a number of unknown variables, assumptions were made regarding environmental and waste conditions that controlled microbial activity; however, it was concluded that 14 C and 3 H would be produced, albeit over a long time scale of about 1500 years for 14 C in the worst case situation

  18. Experimental determinations of soil copper toxicity to lettuce (Lactuca sativa) growth in highly different copper spiked and aged soils.

    Science.gov (United States)

    Christiansen, Karen S; Borggaard, Ole K; Holm, Peter E; Vijver, Martina G; Hauschild, Michael Z; Peijnenburg, Willie J G M

    2015-04-01

    Accurate knowledge about factors and conditions determining copper (Cu) toxicity in soil is needed for predicting plant growth in various Cu-contaminated soils. Therefore, effects of Cu on growth (biomass production) of lettuce (Lactuca sativa) were tested on seven selected, very different soils spiked with Cu and aged for 2 months at 35 °C. Cu toxicity was expressed as pEC50(Cu(2+)), i.e., the negative logarithm of the EC50(Cu(2+)) activity to plant growth. The determined pEC50(Cu(2+)) was significantly and positively correlated with both the analytically readily available soil pH and concentration of dissolved organic carbon [DOC] which together could explain 87% of the pEC50(Cu(2+)) variation according to the simple equation: pEC50(Cu(2+)) = 0.98 × pH + 345 × [DOC] - 0.27. Other soil characteristics, including the base cation concentrations (Na(+), K(+), Ca(2+), Mg(2+)), the cation exchange capacity at soil pH (ECEC), and at pH 7 (CEC7), soil organic carbon, clay content, and electric conductivity as well as the distribution coefficient (Kd) calculated as the ratio between total soil Cu and water-extractable Cu did not correlate significantly with pEC50(Cu(2+)). Consequently, Cu toxicity, expressed as the negative log of the Cu(2+) activity, to plant growth increases at increasing pH and DOC, which needs to be considered in future management of plant growth on Cu-contaminated soils. The developed regression equation allows identification of soil types in which the phytotoxicity potential of Cu is highest.

  19. Assimilable organic carbon (AOC in soil water extracts using Vibrio harveyi BB721 and its implication for microbial biomass.

    Directory of Open Access Journals (Sweden)

    Jincai Ma

    Full Text Available Assimilable organic carbon (AOC is commonly used to measure the growth potential of microorganisms in water, but has not yet been investigated for measuring microbial growth potential in soils. In this study, a simple, rapid, and non-growth based assay to determine AOC in soil was developed using a naturally occurring luminous strain Vibrio harveyi BB721 to determine the fraction of low molecular weight organic carbon in soil water extract. Calibration of the assay was achieved by measuring the luminescence intensity of starved V. harveyi BB721 cells in the late exponential phase with a concentration range from 0 to 800 µg l(-1 glucose (equivalent to 0-16.0 mg glucose C kg(-1 soil with the detection limit of 10 µg l(-1 equivalent to 0.20 mg glucose C kg(-1 soil. Results showed that bioluminescence was proportional to the concentration of glucose added to soil. The luminescence intensity of the cells was highly pH dependent and the optimal pH was about 7.0. The average AOC concentration in 32 soils tested was 2.9±2.2 mg glucose C kg(-1. Our data showed that AOC levels in soil water extracts were significantly correlated (P<0.05 with microbial biomass determined as microbial biomass carbon, indicating that the AOC concentrations determined by the method developed might be a good indicator of soil microbial biomass. Our findings provide a new approach that may be used to determine AOC in environmental samples using a non-growth bioluminescence based assay. Understanding the levels of AOC in soil water extract provides new insights into our ability to estimate the most available carbon pool to bacteria in soil that may be easily assimilated into cells for many metabolic processes and suggest possible the links between AOC, microbial regrowth potential, and microbial biomass in soils.

  20. Towards the understanding of microbial metabolism in relation to microbial enhanced oil recovery

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Nielsen, Kristian Fog

    2017-01-01

    In this study, Bacillus licheniformis 421 was used as a model organism to understand the effects of microbial cell growth and metabolite production under anaerobic conditions in relation to microbial enhanced oil recovery. The bacterium was able to grow anaerobically on different carbon compounds...

  1. Model for determining vapor equilibrium rates in the hanging drop method for protein crystal growth

    Science.gov (United States)

    Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

    1987-01-01

    An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented. Results are applied to 18 drop and well arrangements commonly encountered in the laboratory. The chemical nature of the salt, drop size and shape, drop concentration, well size, well concentration, and temperature are taken into account. The rate of evaporation increases with temperature, drop size, and the salt concentration difference between the drop and the well. The evaporation in this model possesses no unique half-life. Once the salt in the drop achieves 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

  2. Microbial Flocculant for Nature Soda

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Peiyong; Zhang, Tong; Chen, Cuixian

    2004-03-31

    Microbial flocculant for nature soda has been studied. Lactobacillus TRJ21, which was able to produce an excellent biopolymer flocculant for nature soda, was obtained in our lab. The microbial flocculant was mainly produced when the bacteria laid in stationary growth phase. Fructose or glucose, as carbon sources, were more favorable for the bacterial growth and flocculant production. The bacteria was able to use ammonium sulfate or Urea as nitrogen to produce flocculant, but was not able to use peptone effectively. High C/N ratio was more favorable to Lactobacillus TRJ21 growth and flocculant production than low C/N ratio. The biopolymer flocculant was mainly composed of polysaccharide and protein with a molecular weight 1.38x106 by gel permeation chromatography. It was able to be easily purified from the culture medium by acetone. Protein in the flocculant was tested for the flocculating activity ingredient by heating the flocculant.

  3. Determining

    Directory of Open Access Journals (Sweden)

    Bahram Andarzian

    2015-06-01

    Full Text Available Wheat production in the south of Khuzestan, Iran is constrained by heat stress for late sowing dates. For optimization of yield, sowing at the appropriate time to fit the cultivar maturity length and growing season is critical. Crop models could be used to determine optimum sowing window for a locality. The objectives of this study were to evaluate the Cropping System Model (CSM-CERES-Wheat for its ability to simulate growth, development, grain yield of wheat in the tropical regions of Iran, and to study the impact of different sowing dates on wheat performance. The genetic coefficients of cultivar Chamran were calibrated for the CSM-CERES-Wheat model and crop model performance was evaluated with experimental data. Wheat cultivar Chamran was sown on different dates, ranging from 5 November to 9 January during 5 years of field experiments that were conducted in the Khuzestan province, Iran, under full and deficit irrigation conditions. The model was run for 8 sowing dates starting on 25 October and repeated every 10 days until 5 January using long-term historical weather data from the Ahvaz, Behbehan, Dezful and Izeh locations. The seasonal analysis program of DSSAT was used to determine the optimum sowing window for different locations as well. Evaluation with the experimental data showed that performance of the model was reasonable as indicated by fairly accurate simulation of crop phenology, biomass accumulation and grain yield against measured data. The normalized RMSE were 3%, 2%, 11.8%, and 3.4% for anthesis date, maturity date, grain yield and biomass, respectively. Optimum sowing window was different among locations. It was opened and closed on 5 November and 5 December for Ahvaz; 5 November and 15 December for Behbehan and Dezful;and 1 November and 15 December for Izeh, respectively. CERES-Wheat model could be used as a tool to evaluate the effect of sowing date on wheat performance in Khuzestan conditions. Further model evaluations

  4. The effect of river water circulation on the distribution and functioning of reservoir microbial communities as determined by a relative distance approach

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Comerma, M.; García, J. C.; Nedoma, Jiří; Marcé, R.; Armengol, J.

    2011-01-01

    Roč. 14, č. 1 (2011), s. 1-14 ISSN 1432-9840 R&D Projects: GA ČR(CZ) GA206/08/0015 Institutional research plan: CEZ:AV0Z60170517 Keywords : canyon-shaped reservoir * ongitudinal gradients * relative distance model * river-reservoir ecosystem * water circulation patterns * plankton succession * microbial dynamics Subject RIV: EE - Microbiology, Virology Impact factor: 3.495, year: 2011

  5. Modelling microbial interactions and food structure in predictive microbiology

    NARCIS (Netherlands)

    Malakar, P.K.

    2002-01-01

    Keywords: modelling, dynamic models, microbial interactions, diffusion, microgradients, colony growth, predictive microbiology.

    Growth response of microorganisms in foods is a complex process. Innovations in food production and preservation techniques have resulted in adoption of

  6. The Determination of National Growth Charts to Prevent and Manage Malnutrition in Iranian Children: Necessity and Importance

    International Nuclear Information System (INIS)

    Abtahi, Mitra; Doustmohammadian, Aazam; Pouraram, Hamed

    2014-01-01

    Full text: Objectives: Standard height and weight charts are the most important evaluation tools for the assessment of growth and development of children which could be further used to develop preventive interventions both in individual and epidemiologic assessments in the community. Children of different populations differ a lot in size and shape, resulting from differences in their genetic pattern, their needs and interaction of these two. Regarding the existence of different standards, it seems that a national standard can provide a more accurate functional individual and social evaluation tool and many problems will be solved in case of availability of an Iranian standard for comparison of children’s height, weight, and their growth follow-ups. One of these problems is the abnormal results regarding mal nourishment, overweight, or obesity in Iranian children. Considerable rate of childhood malnutrition in Iran and other countries necessitates the implementation of interventional programs including development of local growth charts to prevent and manage malnutrition in the community. This study was undertaken with the aim of reviewing different current growth curves, their advantages and disadvantages, and performing a review of the studies conducted in Iran and other countries on determination of weight and height standards. Methods: In order to collect materials for this review, a detailed search of Scientific Information Database (SID), Iran Medex, MEDLINE, Pub Med, and Web of Science was carried out for the time period 2005-2011 using the keywords: national standard, height, weight, children, and growth chart. Initially, we reviewed international standards of weight and height. Results: The results of performed studies in European and Asian countries showed that the height and weight curves of these children were different from WHO and NCHS growth standards. The finding of growth trend study of Iranian children showed that the mean height and weight of

  7. Radiosensitivity of different human tumor cells lines grown as multicellular spheroids determined from growth curves and survival data

    International Nuclear Information System (INIS)

    Schwachoefer, J.H.C.; Crooijmans, R.P.; van Gasteren, J.J.; Hoogenhout, J.; Jerusalem, C.R.; Kal, H.B.; Theeuwes, A.G.

    1989-01-01

    Five human tumor cell lines were grown as multicellular tumor spheroids (MTS) to determine whether multicellular tumor spheroids derived from different types of tumors would show tumor-type dependent differences in response to single-dose irradiation, and whether these differences paralleled clinical behavior. Multicellular tumor spheroids of two neuroblastoma, one lung adenocarcinoma, one melanoma, and a squamous cell carcinoma of the oral tongue, were studied in terms of growth delay, calculated cell survival, and spheroid control dose50 (SCD50). Growth delay and cell survival analysis for the tumor cell lines showed sensitivities that correlated well with clinical behavior of the tumor types of origin. Similar to other studies on melanoma multicellular tumor spheroids our spheroid control dose50 results for the melanoma cell line deviated from the general pattern of sensitivity. This might be due to the location of surviving cells, which prohibits proliferation of surviving cells and hence growth of melanoma multicellular tumor spheroids. This study demonstrates that radiosensitivity of human tumor cell lines can be evaluated in terms of growth delay, calculated cell survival, and spheroid control dose50 when grown as multicellular tumor spheroids. The sensitivity established from these evaluations parallels clinical behavior, thus offering a unique tool for the in vitro analysis of human tumor radiosensitivity

  8. Calorimetric determination of inhibition of ice crystal <