scholarly journals Persistence of Bacteroides Species Populations in a River as Measured by Molecular and Culture Techniques

2010 ◽  
Vol 76 (22) ◽  
pp. 7608-7616 ◽  
Author(s):  
Elisenda Ballesté ◽  
Anicet R. Blanch
Keyword(s):  
Survival Rates ◽  
Environmental Parameters ◽  
Molecular Techniques ◽  
Fecal Coliforms ◽  
Source Tracking ◽  
Experimental Conditions ◽  
Culture Techniques ◽  
Do Concentration ◽  
Survival Patterns ◽  
Main Factor

ABSTRACT Given the interest in Bacteroides species as microbial source tracking (MST) markers, and the limited knowledge of the survival of Bacteroides species in the environment, here we examine the survival of Bacteroides fragilis, B. thetaiotaomicron, and environmental species of Bacteroides by use of culture techniques and molecular tools. Two kinds of experiments were performed: (i) on-site experiments, in which bacteria were exposed to changes in the levels of several environmental parameters in a river, and (ii) microcosm assays in the laboratory, with controlled temperatures. On-site experiments showed different survival patterns for the cultivable Bacteroides strains. B. fragilis die-off rate was strongly affected by the combined effect of high temperatures and grazing predators, which were more active under warmer conditions. However, the survival rates of cultivable B. thetaiotaomicron and environmental Bacteroides spp. were more affected by dissolved oxygen (DO) concentration in water. Environmental Bacteroides strains survived longer than either type strain, due to better adaptation to environmental conditions. However, the period of their survival was shorter than that observed for fecal coliforms and enterococci, suggesting Bacteroides species as markers of recent fecal pollution. The total Bacteroides species were detected by molecular techniques throughout the experiment in winter, but they were detected on only two or three days in the summer. This indicates that temperature is the main factor affecting DNA degradation, regardless of species. The use of microcosms in the laboratory also pointed to temperature as the main factor affecting Bacteroides survival, regardless of species. However, the conditions in the laboratory may mask the effects of the environmental factors and their interactions. The observed variability in die-off rate as a function of the species analyzed, the experimental conditions, and the methodology used should be taken into consideration in future persistence studies.

scholarly journals Quantifying the contribution of microbial immigration in engineered water systems

Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Ran Mei ◽  
Wen-Tso Liu
Keyword(s):  
Mass Balance ◽  
Environmental Parameters ◽  
Balance Model ◽  
Source Tracking ◽  
Community Function ◽  
High Throughput Dna Sequencing ◽  
Abundance Profile ◽  
Downstream Communities ◽  
And Function ◽  
Quantitative Contribution

Abstract Immigration is a process that can influence the assembly of microbial communities in natural and engineered environments. However, it remains challenging to quantitatively evaluate the contribution of this process to the microbial diversity and function in the receiving ecosystems. Currently used methods, i.e., counting shared microbial species, microbial source tracking, and neutral community model, rely on abundance profile to reveal the extent of overlapping between the upstream and downstream communities. Thus, they cannot suggest the quantitative contribution of immigrants to the downstream community function because activities of individual immigrants are not considered after entering the receiving environment. This limitation can be overcome by using an approach that couples a mass balance model with high-throughput DNA sequencing, i.e., ecogenomics-based mass balance. It calculates the net growth rate of individual microbial immigrants and partitions the entire community into active populations that contribute to the community function and inactive ones that carry minimal function. Linking activities of immigrants to their abundance further provides quantification of the contribution from an upstream environment to the downstream community. Considering only active populations can improve the accuracy of identifying key environmental parameters dictating process performance using methods such as machine learning.

scholarly journals Model analysis of the relationship between intracellular Po2 and energy demand in skeletal muscle

2012 ◽  
Vol 303 (11) ◽  
pp. R1110-R1126 ◽  
Author(s):  
Jessica Spires ◽  
L. Bruce Gladden ◽  
Bruno Grassi ◽  
Gerald M. Saidel ◽  
Nicola Lai
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Contraction ◽  
Energy Demand ◽  
Experimental Studies ◽  
Experimental Conditions ◽  
Permeability Surface ◽  
The Relationship ◽  
And Diffusion ◽  
Main Factor

On the basis of experimental studies, the intracellular O2 (iPo2)-work rate (WR) relationship in skeletal muscle is not unique. One study found that iPo2 reached a plateau at 60% of maximal WR, while another found that iPo2 decreased linearly at higher WR, inferring capillary permeability-surface area ( PS) and blood-tissue O2 gradient, respectively, as alternative dominant factors for determining O2 diffusion changes during exercise. This relationship is affected by several factors, including O2 delivery and oxidative and glycolytic capacities of the muscle. In this study, these factors are examined using a mechanistic, mathematical model to analyze experimental data from contracting skeletal muscle and predict the effects of muscle contraction on O2 transport, glycogenolysis, and iPo2. The model describes convection, O2 diffusion, and cellular metabolism, including anaerobic glycogenolysis. Consequently, the model simulates iPo2 in response to muscle contraction under a variety of experimental conditions. The model was validated by comparison of simulations of O2 uptake with corresponding experimental responses of electrically stimulated canine muscle under different O2 content, blood flow, and contraction intensities. The model allows hypothetical variation of PS, glycogenolytic capacity, and blood flow and predictions of the distinctive effects of these factors on the iPo2-contraction intensity relationship in canine muscle. Although PS is the main factor regulating O2 diffusion rate, model simulations indicate that PS and O2 gradient have essential roles, depending on the specific conditions. Furthermore, the model predicts that different convection and diffusion patterns and metabolic factors may be responsible for different iPo2-WR relationships in humans.

scholarly journals Diversity and antifungal susceptibility of yeasts isolated by multiple-tube fermentation from three freshwater lakes in Brazil

2009 ◽  
Vol 8 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Luciana R. Brandão ◽  
Adriana O Medeiros ◽  
Mariana C. Duarte ◽  
Anne C. Barbosa ◽  
Carlos A. Rosa
Keyword(s):  
Amphotericin B ◽  
Heterotrophic Bacteria ◽  
Yeast Species ◽  
Antifungal Susceptibility ◽  
Molecular Techniques ◽  
Antifungal Drugs ◽  
Fecal Coliforms ◽  
Southeastern Brazil ◽  
The People ◽  
Enterococcus Spp

The diversity and antifungal resistance of yeasts able to grow at 37°C and the occurrence of bacterial indicators of water quality were studied in three lakes in Southeastern Brazil. The densities of yeasts, Escherichia coli, Enterococcus spp. and Pseudomonasaeruginosa were determined by the multiple-tube fermentation technique, and counts of heterotrophic bacteria were determined using the pour plate method. The yeasts were identified using physiological and molecular techniques and their resistance to amphotericin B, itraconazole and fluconazole was tested. Yeast occurrence was significantly correlated only with the density of fecal coliforms. Candida krusei, C. guilliermondii and C. tropicalis, the most frequently isolated yeast species, are associated with fecal contamination of water by warm-blooded animals. Yeast isolates were most resistant to amphotericin B (21.7%), followed by itraconazole (20%) and then fluconazole (2.8%). In addition to tests for the fecal coliform group, the density of yeasts grown at 37°C could be used as a complementary microbial indicator that aquatic environments contain organic matter of human origin. The incidence of yeast species resistant to three antifungal drugs shows that these microorganisms could pose a health risk to the people who use these lakes for recreation.

Concrete and Abstract Terms and Relations in Testing a Rule

1974 ◽  
Vol 26 (3) ◽  
pp. 355-359 ◽  
Author(s):  
K. J. Gilhooly ◽  
W. A. Falconer
Keyword(s):  
Abstract Form ◽  
Experimental Conditions ◽  
Improved Performance ◽  
Main Factor

Subjects have more difficulty in correctly testing a conditional rule stated in abstract form than the same rule given in “thematic” form. The “thematic” form of the rule involves both concrete terms and a concrete relation. Four experimental conditions were formed by combining concrete abstract terms and relations. Fifty subjects were tested in each condition. The results indicated that concrete-ness of the terms is the main factor leading to improved performance with “thematic” as against abstract material in the rule testing task.

scholarly journals LabHorta: a controlled aquarium system for monitoring physiological characteristics of the hydrothermal vent mussel Bathymodiolus azoricus

2010 ◽  
Vol 68 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Ana Colaço ◽  
Raul Bettencourt ◽  
Valentina Costa ◽  
Silvia Lino ◽  
Humberto Lopes ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Experimental Studies ◽  
Environmental Parameters ◽  
Condition Index ◽  
Physiological Characteristics ◽  
Good Tool ◽  
Experimental Conditions ◽  
Menez Gwen

AbstractColaço, A., Bettencourt, R., Costa, V., Lino, S., Lopes, H., Martins, I., Pires, L., Prieto, C., and Serrão Santos, R. 2011. LabHorta: a controlled aquarium system for monitoring physiological characteristics of the hydrothermal vent mussel Bathymodiolus azoricus. – ICES Journal of Marine Science, 68: 349–356. LabHorta is a facility composed of laboratories and retrievable deep-sea cages created to support and expand the capabilities of research cruises. It also enhances the ability to conduct experimental studies with organisms from deep-sea hydrothermal vents and other deep-sea environments, while keeping them under controlled conditions of pressure and water chemistry. This paper presents a case study with the vent mussel Bathymodiolus azoricus (which harbours a dual symbiosis) collected at the Menez Gwen hydrothermal vent field at 840-m depth, transported to experimental aquaria at atmospheric pressure and maintained under four different controlled experimental conditions to study their comparative condition index (CI). Environmental parameters were monitored daily and efforts were made to keep these constant. During the first few months, there were differences between the CI scores of mussels kept under the various conditions. After 6 months, the differences are not so clear but mussels still had sulphur-oxidizing bacteria when fed with sulphide. The methane oxidizer bacteria disappear even in the presence of methane. A range of CI scores appeared as a function of the culture type. The LabHorta facility is a good tool for performing long-term physiological studies of deep-sea organisms, simulating possible changes in the natural environmental where they normally thrive.

Analysis of nitrifying bacterial communities in aerobic biofilm reactors with different DO conditions using molecular techniques

2008 ◽  
Vol 57 (12) ◽  
pp. 1889-1899 ◽  
Author(s):  
J. J. Park ◽  
I. G. Byun ◽  
J. C. Yu ◽  
S. R. Park ◽  
D. J. Ju ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Denaturing Gradient Gel Electrophoresis ◽  
In Situ Hybridisation ◽  
Amoa Gene ◽  
Biofilm Reactor ◽  
Molecular Techniques ◽  
Fluorescence In Situ Hybridisation ◽  
Do Concentration ◽  
Pcr Targeting ◽  
The Relationship

In order to assess the relationship between the dissolved oxygen (DO) concentration and the characteristics of nitrifying bacterial communities in an aerobic biofilm reactor, molecular techniques including denaturing gradient gel electrophoresis (DGGE)/cloning based on PCR targeting 16S rRNA and the amoA gene and fluorescence in situ hybridisation (FISH) were conducted. The D-1, D-2, D-3 and D-4 reactors with different DO concentrations (1, 3, 5 and 7 mg/L, respectively) were set up in the thermostat and acclimated. The optimal DO concentration with stable nitrification efficiency was above 5.0 mg/L. As was shown by the results of DGGE and cloning, the community of ammonia-oxidising bacteria (AOB) and the ratio of Nitrosomonas sp. changed only slightly despite their differing nitrification efficiencies. The results of FISH indicated that higher DO concentrations resulted in an increase in AOB and nitrite-oxidising bacteria (NOB), and a reduction in heterotrophic microorganisms. The INT-dehydrogenase activity (DHA) test demonstrated that the activity of AOB decreased with reductions in the DO concentration. This means that the DO concentration does not influence the community of AOB, but rather the activity of AOB. In the relationship between the attached biomass and the nitrification efficiency, only the active biomass affected the nitrification efficiencies.

scholarly journals Implementation and Integration of Microbial Source Tracking in a River Watershed Monitoring Plan

2019 ◽  
Author(s):  
Elisenda Ballesté ◽  
Katalin Demeter ◽  
Bartholomew Masterson ◽  
Natàlia Timoneda ◽  
Wim G. Meijer
Keyword(s):  
Land Use ◽  
Environmental Parameters ◽  
High Sensitivity ◽  
Significant Negative Correlation ◽  
Microbial Source Tracking ◽  
Environmental Data ◽  
Source Tracking ◽  
Sources Of Pollution ◽  
Set Up ◽  
Human Pollution

AbstractFecal pollution of water bodies poses a serious threat for public health and ecosystems. Microbial source tracking (MST) using host specific bacteria are used to track the source of this potential pollution and be able to perform a better management of the pollution at the source. In this study we tested 12 molecular MST markers to track human, ruminant, sheep, horse, pig and gull pollution to determine their usefulness in their application for an effective management of water quality. First, the potential of the selected markers to track the source was evaluated using fresh fecal samples. Subsequently, we evaluated their performance in a catchment with different impacts, considering land use and environmental conditions. All MST markers showed high sensitivity and specificity, although none achieved 100% for both. Although some of the MST markers were detected in hosts other than the intended ones, their abundance in the target group was always several orders of magnitude higher than in the non-target hosts, demonstrating their suitability to distinguish between sources of pollution. The MST analysis matched the land use in the watershed allowing a very accurate assessment of the main hazards and sources of pollution, in this case mainly human and ruminant pollution. Correlating environmental parameters like temperature and rainfall with the levels of the MST markers provided insight into the dynamics of the pollution along the catchment. The levels of the human associated marker showed a significant negative correlation with rainfall in human polluted areas suggesting a dilution of the pollution, whereas at agricultural areas the ruminant marker increased with rainfall. There were no seasonal differences in the levels of human marker, indicating human pollution as a constant pressure throughout the year, whereas the levels of the ruminant marker was influenced by the seasons, being more abundant in summer and autumn. Performing MST analysis integrated with land uses and environmental data can improve the management of fecal polluted areas and set up good practices.

scholarly journals Study of Seaweed Kappaphycus alvarezii Explants Growth in the Different Salinity Concentrations

2021 ◽  
Vol 13 (1) ◽  
pp. 97
Author(s):  
Muhammad Aris ◽  
Fatma Muchdar ◽  
Rusmawati Labenua
Keyword(s):  
Tissue Culture ◽  
Kappaphycus Alvarezii ◽  
Environmental Parameters ◽  
Culture Method ◽  
Salinity Treatment ◽  
Culture Methods ◽  
Culture Techniques ◽  
Randomized Design ◽  
Salinity Levels

HighlightThe best salinity for the thallus growth of K. alvarezii is 32 mg/LThe salinity indicates the osmotic balance of K. alvarezii seaweedThis osmoregulation process affects the nutrient absorption of K. alvarezii seaweedThis study aims to develop the availibility of superior seeds of K. alvareziiAbstract Kappaphycus alvarezii is one of the leading commodities in Indonesian waters. Demand for this commodity is quite high, as reflected in the increasing volume of exports each year. Fulfillment of these demands is obtained from the production of cultivation. Generally farmers get natural seaweed seedlings, namely cuttings from existing seaweed. The continuous use of seeds from nature can cause deterioration in the quality and quantity. Handling the problem of quality deterioration from seaweed seeds originating from nature, can be overcome by multiplying the seeds through tissue culture methods in vitro. In term of tissue culture techniques method, the most important thing to note is environmental parameters. An environment parameter that changes suddenly such as salinity can inhibit the growth of seaweed. Thus, this work is attampting the different salinity treatment on seaweed explants K. alvarezii. This study aims at determining (weight) the explants of K. alvarezii with a comparison of the different salinity levels in the in vitro tissue culture method. The method used in this study was a completely randomized design (CRD) with the different salinity treatments namely 30, 31, 32, 33, and 34 ppt. The results showed that the different salinities influenced the growth rate of K. alvarezii seaweed explants with the best explant growth at the salinity of 31 ppt, while the lowest growth value was obtained at 34 ppt

scholarly journals Isolation and selection of bacteria inhibiting Streptococcus agalactiae causing dark-body disease on snakeskin gourami fish (Trichogaster pectoralis)

2021 ◽  
Vol 19 (3) ◽  
pp. 547-555
Author(s):  
Le Thi Anh Hong ◽  
Pham Thi Minh Ngoc ◽  
Duong Khanh ◽  
Vo Van Tuan ◽  
Nguyen Hoang Dung
Keyword(s):  
Streptococcus Agalactiae ◽  
Pathogenic Bacteria ◽  
Survival Rates ◽  
Microbial Pathogens ◽  
Control Treatment ◽  
Fish Ponds ◽  
16S Rrna Sequence ◽  
Experimental Conditions ◽  
Experimental Treatments ◽  
Dark Body

Streptococcus agalactiae is one of the microbial pathogens causing the dark-body disease on snakeskin gourami fish (Trichogaster pectoralis) that affects the growth and quality of fish. This research aimed to isolate and select bacteria inhibiting S. agalactiae which are able to use for controling pathogenic bacteria instead of antibiotics. Fourteen bacteria strains were isolated and screened from healthy fishes, sediment and water samples at fish ponds in Dong Thap province. Among these strains, L7 strain showed the highest inhibition ability with the clear zone diameter was 9,3 mm. The results of the 16S rRNA sequence analysis indicated that the L7 strain belonged to Bacillus subtilis. The experiment to evaluate the inhibition capacity and fish disease control of selected B. subtilis in experimental conditions was conducted by challenging fish with S. agalactiae. Fishes in the control treatment was infected with S. agalactiae at 106 CFU/mL had survival rate 41,7%. The experimental treatments NT1, NT2, NT3 which were treated with B. subtilis at concentrations of 105 CFU/mL, 106 CFU/mL, and 107 CFU/mL gave higher survival rates compared with the non-treated control, with the rates of 60%, 76,7%, and 81,7%, respectively. These results revealed that the isolated B. subtilis is potential used in control dark-body disease on snakeskin gourami fish.

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