scholarly journals Variation in Prokaryotic Community Composition as a Function of Resource Availability in Tidal Creek Sediments

2008 ◽  
Vol 74 (6) ◽  
pp. 1836-1844 ◽  
Author(s):  
Jennifer W. Edmonds ◽  
Nathanial B. Weston ◽  
Samantha B. Joye ◽  
Mary Ann Moran
Keyword(s):  
Community Composition ◽  
Tidal Creek ◽  
Bacterial Species ◽  
Dynamic Environment ◽  
Coastal Sediments ◽  
Polymorphism Analysis ◽  
Molecular Approaches ◽  
Carbon Supply ◽  
Resource Level ◽  
Fermentative Bacteria

ABSTRACT In anaerobic coastal sediments, hydrolytic and/or fermentative bacteria degrade polymeric material and produce labile intermediates, which are used by terminal metabolizers to complete the conversion of organic material to CO2. We used molecular approaches to evaluate the response of two bacterial terminal metabolizer groups from a coastal tidal creek sediments, sulfate reducers and methanogens, to controlled changes in carbon resource supply. Tidal creek sediment bioreactors were established in April and August 2004. For each date, intact sediment sections were continuously supplied with flowthrough seawater that was either unamended or amended with the high-molecular-weight polysaccharide dextran. Biogeochemical data indicate that the activity of fermenting bacteria and the terminal metabolizers was limited by organic carbon supply during both experiments, with a significant increase in net volatile fatty acid (VFA) production and rates of sulfate reduction and methanogenesis following dextran addition. Community composition (measured by using terminal restriction fragment length polymorphism analysis, and functional gene [dsrA, mcrA] clone libraries) changed from April to August. However, community composition was not different between amended and unamended cores within each month, despite the change in resource level. Moreover, there was no relationship between community richness and evenness with resource level. This lack of variation in community composition with C addition could be attributed to the dynamic environment these sediment communities experience in situ. Fluctuations in VFA concentrations are most likely very high, so that the dominant bacterial species must be able to outcompete other species at both high and low resource levels.

scholarly journals Capsule-Transmitted Gut Symbiotic Bacterium of the Japanese Common Plataspid Stinkbug, Megacopta punctatissima

2002 ◽  
Vol 68 (1) ◽  
pp. 389-396 ◽  
Author(s):  
Takema Fukatsu ◽  
Takahiro Hosokawa
Keyword(s):  
Bacterial Species ◽  
Symbiotic Bacterium ◽  
Egg Mass ◽  
Polymorphism Analysis ◽  
Host Insect ◽  
Fitness Effects ◽  
Body Coloration ◽  
Molecular Phylogenetic ◽  
Microbiological Aspects

ABSTRACT The Japanese common plataspid stinkbug, Megacopta punctatissima, deposits small brown particles, or symbiont capsules, on the underside of the egg mass for the purpose of transmission of symbiotic bacteria to the offspring. We investigated the microbiological aspects of the bacteria contained in the capsule, such as microbial diversity, phylogenetic placement, localization in vivo, and fitness effects on the host insect. Restriction fragment length polymorphism analysis of 16S ribosomal DNA clones revealed that a single bacterial species dominates the microbiota in the capsule. The bacterium was not detected in the eggs but in the capsules, which unequivocally demonstrated that the bacterium is transmitted to the offspring of the insect orally rather than transovarially, through probing of the capsule content. Molecular phylogenetic analysis showed that the bacterium belongs to the γ-subdivision of the Proteobacteria. In adult insects the bacterium was localized in the posterior section of the midgut. Deprivation of the bacterium from the nymphs resulted in retarded development, arrested growth, abnormal body coloration, and other symptoms, suggesting that the bacterium is essential for normal development and growth of the host insect.

scholarly journals Temporal Dynamics of South End Tidal Creek (Sapelo Island, Georgia) Bacterial Communities

2008 ◽  
Vol 75 (4) ◽  
pp. 1058-1064 ◽  
Author(s):  
Emily Kara ◽  
Ashley Shade
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Community Dynamics ◽  
Tidal Creek ◽  
Temporal Dynamics ◽  
Bacterial Community Composition ◽  
High Tide ◽  
Cycle Period ◽  
Sapelo Island ◽  
End Tidal

ABSTRACT Bacterial community dynamics in South End tidal creek, Sapelo Island, GA, were studied over a 74-h, five-tidal-cycle period. Observations were made hourly for the first consecutive 24 hours, every 3 hours on the second day, and every 6 hours on the third day. Tide most strongly influenced bacterial community composition (high-tide versus low-tide community analysis of similarities, R = 0.41, P < 0.03). Dissolved oxygen concentration and conductivity were important proximate drivers. However, after accounting for tide and environmental variables colinear with tide, cumulative time became more important in describing community variation. In-stream physical processes, including particulate suspension and sedimentation, may explain tide-associated trends in the bacterial community composition observed.

scholarly journals Application of Methods for Identifying Broiler Chicken Gut Bacterial Species Linked with Increased Energy Metabolism

2007 ◽  
Vol 74 (3) ◽  
pp. 783-791 ◽  
Author(s):  
Valeria A. Torok ◽  
Kathy Ophel-Keller ◽  
Maylene Loo ◽  
Robert J. Hughes
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Community Composition ◽  
Bacterial Species ◽  
Bacterial Community Composition ◽  
Microbial Community Composition ◽  
Metabolizable Energy ◽  
Principal Coordinates ◽  
Improved Performance ◽  
Gut Microbial Community

ABSTRACT A high-throughput microbial profiling tool based on terminal restriction fragment length polymorphism was developed to monitor the poultry gut microbiota in response to dietary manipulations. Gut microbial communities from the duodena, jejuna, ilea, and ceca of 48 birds fed either a barley control diet or barley diet supplemented with exogenous enzymes for degrading nonstarch polysaccharide were characterized by using multivariate statistical methods. Analysis of samples showed that gut microbial communities varied significantly among gut sections, except between the duodenum and jejunum. Significant diet-associated differences in gut microbial communities were detected within the ileum and cecum only. The dissimilarity in bacterial community composition between diets was 73 and 66% within the ileum and cecum, respectively. Operational taxonomic units, representing bacterial species or taxonomically related groups, contributing to diet-associated differences were identified. Several bacterial species contributed to differences between diet-related gut microbial community composition, with no individual bacterial species contributing more than 1 to 5% of the total. Using canonical analysis of principal coordinates biplots, we correlated differences in gut microbial community composition within the ileum and cecum to improved performance, as measured by apparent metabolizable energy. This is the first report that directly links differences in the composition of the gut microbial community with improved performance, which implies that the presence of specific beneficial and/or absence of specific detrimental bacterial species may contribute to the improved performance in these birds.

scholarly journals Biofilm and Planktonic Bacterial and Fungal Communities Transforming High-Molecular-Weight Polycyclic Aromatic Hydrocarbons

2016 ◽  
Vol 82 (8) ◽  
pp. 2288-2299 ◽  
Author(s):  
Benjamin D. Folwell ◽  
Terry J. McGenity ◽  
Corinne Whitby
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
High Molecular Weight ◽  
Community Composition ◽  
Aromatic Hydrocarbons ◽  
Fungal Community ◽  
Bacterial Species ◽  
Bacterial Community Composition ◽  
Content Type ◽  
Polycyclic Aromatic

ABSTRACTHigh-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[a]pyrene (44% ± 13.6%) and benzo[b]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs werePseudomonas,Bacillus, andMicrobacteriumspecies. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation.

scholarly journals Epidemiological situation of human leptospirosis in Brazil and challenges in its diagnosis with a focus on molecular approaches

Biotemas ◽  
2021 ◽  
Vol 34 (4) ◽  
pp. 1-13
Author(s):  
Andressa Penedo de Paiva Estrella ◽  
Amanda Silva Hecktheuer ◽  
Fabienne Antunes Ferreira ◽  
Ricardo Ruiz Mazzon
Keyword(s):  
Diagnostic Test ◽  
Agglutination Test ◽  
Diagnostic Methods ◽  
Polymorphism Analysis ◽  
General View ◽  
Routine Test ◽  
Human Leptospirosis ◽  
Molecular Approaches ◽  
Worldwide Distribution ◽  
Causative Agents

Leptospira interrogans is one of the causative agents of human leptospirosis, a zoonotic disease with worldwide distribution. Nowadays, this zoonosis is considered one of the biggest in terms of morbidity and mortality (even considering Dengue, the major arbovirosis affecting humans), having in Brazil 3,800 human cases per year. Currently, difficulties imposed by the absence of a rapid, sensitive diagnostic test that can be used as a routine test for the detection of leptospirosis lead to misdiagnosis and underreported cases. The gold standard diagnostic test for leptospirosis is the microscopic agglutination test (MAT), which presents difficulties in execution and interpretation. Therefore, this review proposes a general view of the epidemiologic situation of the disease in Brazil, in addition to the current contributions in the literature for the development of new diagnostic methods. Amongst them, the gene sequences polymorphism analysis, which presents potential for phylogenetic and populational analysis and genotyping of Leptospira spp.

scholarly journals Soil Water Contents Control the Responses of Dissolved Nitrogen Pools and Bacterial Communities to Freeze-Thaw in Temperate Soils

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Nan Jiang ◽  
Yinghua Juan ◽  
Lulu Tian ◽  
Xiaodong Chen ◽  
Wentao Sun ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Soil Water ◽  
Community Composition ◽  
Bacterial Communities ◽  
N Mineralization ◽  
Bacterial Species ◽  
Bacterial Community Composition ◽  
N Immobilization ◽  
Freeze Thaw ◽  
Dissolved Nitrogen

Background. Freeze-thaw influences soil-dissolved nitrogen (N) pools due to variations in bacterial communities in temperate regions. The availability of soil water is important to soil biogeochemical cycles under frozen conditions. However, it is unclear how soil water content (SWC) mediates the effects of freeze-thaw on soil-dissolved N pools and bacterial communities. Method. In this study, freeze-thaw microcosms were incubated at three levels of SWC, including 10% (air-dried soils), 15% (natural SWC), and 30% (wet soils). In addition to measuring soil-dissolved N pools, variations in bacterial communities were examined using high-throughput sequencing. Results and Conclusions. Total dissolved N (TDN), NO3--N, NH4+-N, microbial biomass N (MBN), and net N mineralization rate (NNMR) were significantly influenced by SWC, freeze-thaw, and their interaction (NH4+-N excluded). N immobilization was inhibited under both low and high SWC, which was accompanied by varied bacterial community composition. However, only higher SWC substantially modified the freeze-thaw effects on the soil-dissolved N pools, characterized by a decrease in N mineralization (especially for the content of NO3--N and NNMR) and an increase in N immobilization (MBN). These scenarios could be significantly correlated to variations in bacterial community composition based on redundancy analysis, especially by species belonging to Bacteroidetes, Nitrospirae, Alphaproteobacteria, Gemmatimonadetes, and Verrucomicrobia (Spearman’s correlations). In conclusion, bacterial species passed through biotic (bacterial species) and abiotic filters (soil N pools) in response to freeze-thaw under varied SWC.

Persistence, loss and appearance of bacteria upstream and downstream of a river system

2017 ◽  
Vol 68 (5) ◽  
pp. 851 ◽  
Author(s):  
Lisa M. Dann ◽  
Renee J. Smith ◽  
Thomas C. Jeffries ◽  
Jody C. McKerral ◽  
Peter G. Fairweather ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Anthropogenic Impacts ◽  
Bacterial Species ◽  
Bacterial Community Composition ◽  
Microbial Community Composition ◽  
Ecosystem Dynamics ◽  
Source Tracking ◽  
Freshwater Species ◽  
Rdna Sequencing

Bacterial taxa shape microbial community composition and influence aquatic ecosystem dynamics. Studies on bacterial persistence in rivers have primarily focussed on microbial-source tracking as an indicator for faecal-source contamination, whereas archetypal freshwater species have received minimal attention. The present study describes the river microbial communities upstream and 3.3km downstream of a small rural town. By 16S rDNA sequencing, we report three patterns in microbial community composition, namely, persistence, loss and appearance. Persistence was observed as 46% inter-site similarity, perhaps owing to generalists that have information lengths that exceed 3.3km and are capable of adapting to system fluctuations. Loss was observed as 10% site exclusivity upstream, perhaps owing to removal processes such as predation and lysis during transport downstream. Last, appearance was observed as 44% site exclusivity downstream, indicating potential anthropogenic impacts from land run-off on bacterial community composition. High multivariate dispersion among downstream samples, as well as overall sample dissimilarity, present as microscale hotspots of discrete Firmicutes and Cyanobacteria species, indicated higher heterogeneity downstream, and therefore increased patchiness from downstream transport and inputs of bacterial genotypes. These findings suggest relativities among three fates for bacterial species of fluvial systems, persistence, loss and appearance, with each having different effects on system dynamics.

scholarly journals Molecular Characterization of Subject-Specific Oral Microflora during Initial Colonization of Enamel

2006 ◽  
Vol 72 (4) ◽  
pp. 2837-2848 ◽  
Author(s):  
Patricia I. Diaz ◽  
Natalia I. Chalmers ◽  
Alexander H. Rickard ◽  
Colin Kong ◽  
Craig L. Milburn ◽  
...  
Keyword(s):  
Community Composition ◽  
Bacterial Species ◽  
Microbial Community Composition ◽  
Microbial Colonization ◽  
Rrna Gene ◽  
Dependent Manner ◽  
Clone Libraries ◽  
Tooth Surfaces ◽  
Biofilm Development

ABSTRACT The initial microbial colonization of tooth surfaces is a repeatable and selective process, with certain bacterial species predominating in the nascent biofilm. Characterization of the initial microflora is the first step in understanding interactions among community members that shape ensuing biofilm development. Using molecular methods and a retrievable enamel chip model, we characterized the microbial diversity of early dental biofilms in three subjects. A total of 531 16S rRNA gene sequences were analyzed, and 97 distinct phylotypes were identified. Microbial community composition was shown to be statistically different among subjects. In all subjects, however, 4-h and 8-h communities were dominated by Streptococcus spp. belonging to the Streptococcus oralis/Streptococcus mitis group. Other frequently observed genera (comprising at least 5% of clone sequences in at least one of the six clone libraries) were Actinomyces, Gemella, Granulicatella, Neisseria, Prevotella, Rothia, and Veillonella. Fluorescence in situ hybridization (FISH) confirmed that the proportion of Streptococcus sp. sequences in the clone libraries coincided with the proportion of streptococcus probe-positive organisms on the chip. FISH also revealed that, in the undisturbed plaque, not only Streptococcus spp. but also the rarer Prevotella spp. were usually seen in small multigeneric clusters of cells. This study shows that the initial dental plaque community of each subject is unique in terms of diversity and composition. Repetitive and distinctive community composition within subjects suggests that the spatiotemporal interactions and ecological shifts that accompany biofilm maturation also occur in a subject-dependent manner.

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