scholarly journals Free-living Bacterial Communities Are Mostly Dominated by Oligotrophs

2018 ◽  
Author(s):  
Yingnan Gao ◽  
Martin Wu
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Nutrient Availability ◽  
Bacterial Communities ◽  
Copy Number ◽  
Ecological Strategy ◽  
Natural Habitats ◽  
Free Living ◽  
The Impact ◽  
Copiotrophic Bacteria

AbstractIn response to resource availability, bacteria have evolved two distinct ecological strategies. Copiotrophic bacteria grow fast and are heavily favored by selection where the resource is abundant. In contrast, oligotrophic bacteria grow slowly but more efficiently and are highly adaptive in nutrient-poor environments (Koch, 2001). Although oligotrophs and copiotrophs are ubiquitous, except for a few well-characterized environments like the open ocean and animal gut, the relative abundance of oligotrophic and copiotrophic bacteria and their importance in the global ecosystem are still unclear. In addition, although several studies have demonstrated the impact of nutrient availability on the bacterial community structure under experimental conditions (Klappenbach et al., 2000, Nemergut et al., 2016), the role of nutrients in shaping the structures of bacterial communities in their natural habitats remains largely unknown. Using the ribosomal RNA operon (rrn) copy number to capture the bacterial ecological strategy, we analyzed 44,045 samples from two large bacterial community repositories that cover 78 environmental types. Here we show that animal-associated microbiota are dominated by copiotrophs while plant-associated and free-living bacterial communities are mostly dominated by oligotrophs. Our results suggest that nutrient availability plays an important role in determining the structure and ecological strategy of bacterial communities in nature. We demonstrate that the average and distribution of rrn copy number are simple yet robust predictors of the ecological strategy of bacterial communities that can be applied to all sequence-based microbial surveys to link the community structure and function.

Bacterial communities of the rhizosphere and endorhiza associated with field-grown cucumber plants inoculated with a plant growth-promoting rhizobacterium or its genetically modified derivative

1997 ◽  
Vol 43 (4) ◽  
pp. 344-353 ◽  
Author(s):  
W. F. Mahaffee ◽  
J. W. Kloepper
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Genetically Modified ◽  
Acid Methyl Ester ◽  
Wild Type ◽  
Natural Ecosystems ◽  
Genus Level ◽  
Plant Growth Promoting ◽  
The Impact

The future use of genetically modified microorganisms in the environment will be dependent on the ability to assess potential or theoretical risks associated with their introduction into natural ecosystems. To assess potential risks, several ecological parameters must be examined, including the impact of the introduced genetically modified organism on the microbial communities associated with the environment into which the introduction will occur. A 2-year field study was established to examine whether the indigenous bacterial communities of the rhizosphere and endorhiza (internal root tissues) were affected differently by the introduction of an unaltered wild type and its genetically modified derivative. Treatments consisted of the wild-type strain Pseudomonas fluorescens 89B-27 and a bioluminescent derivative GEM-8 (89B-27::Tn4431). Cucumber root or seed samples were taken 0, 7, 14, 21, 35, and 70 days after planting (DAP) in 1994 and 0, 7, 14, 28, 42, and 70 DAP in 1995. Samples were processed to examine the bacterial communities of both the rhizosphere and endorhiza. Over 7200 bacterial colonies were isolated from the rhizosphere and endorhiza and identified using the Sherlock System (Microbial ID, Inc.) for fatty acid methyl ester analysis. Community structure at the genus level was assessed using genera richness and Hill's diversity numbers, N1 and N2. The aerobic–heterotrophic bacterial community structure at the genus level did not significantly vary between treatments but did differ temporally. The data indicate that the introduction of the genetically modified derivative of 89B-27 did not pose a greater environmental risk than its unaltered wild type with respect to aerobic–heterotrophic bacterial community structure.Key words: diversity, ecology, PGPR, Pseudomonas, root colonizaton, GEM.

scholarly journals Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

2012 ◽  
Vol 9 (12) ◽  
pp. 17401-17435 ◽  
Author(s):  
E. Ortega-Retuerta ◽  
F. Joux ◽  
W. H. Jeffrey ◽  
J.-F. Ghiglione
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
16S Rrna ◽  
Surface Waters ◽  
Bacterial Communities ◽  
Canadian Arctic ◽  
Beaufort Sea ◽  
Free Living ◽  
Open Sea ◽  
Mackenzie River

Abstract. We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea, Canadian Arctic Ocean, with a particular focus on free-living vs. particle-attached communities. Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between particle-attached (PA) and free-living (FL) bacterial communities in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (proxy of DOC and CDOM), suspended particles, amino acids and chlorophyll a. 16S rRNA genes pyrosequencing of selected samples confirmed these significant differences from river to sea and also between PA and FL fractions only in open sea samples, and PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, the coast and river samples, both PA and FL fractions, were dominated by Betaproteobacteria, Alphaproteobacteria and Actinobacteria. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also serve as a~basis to predict further changes in bacterial communities should climate change lead to further increases in river discharge and related particles load.

scholarly journals Biofilm Bacterial Community Structure in Streams Affected by Acid Mine Drainage

2009 ◽  
Vol 75 (11) ◽  
pp. 3455-3460 ◽  
Author(s):  
Gavin Lear ◽  
Dev Niyogi ◽  
Jon Harding ◽  
Yimin Dong ◽  
Gillian Lewis
Keyword(s):  
Community Structure ◽  
Acid Mine Drainage ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Mine Drainage ◽  
Iron Hydroxide ◽  
Acidic Ph ◽  
Dissolved Metals ◽  
Acid Mine ◽  
The Impact

ABSTRACT We examined the bacterial communities of epilithic biofilms in 17 streams which represented a gradient ranging from relatively pristine streams to streams highly impacted by acid mine drainage (AMD). A combination of automated ribosomal intergenic spacer analysis with multivariate analysis and ordination provided a sensitive, high-throughput method to monitor the impact of AMD on stream bacterial communities. Significant differences in community structure were detected among neutral to alkaline (pH 6.7 to 8.3), acidic (pH 3.9 to 5.7), and very acidic (pH 2.8 to 3.5) streams. DNA sequence analysis revealed that the acidic streams were generally dominated by bacteria related to the iron-oxidizing genus Gallionella, while the organisms in very acidic streams were less diverse and included a high proportion of acidophilic eukaryotes, including taxa related to the algal genera Navicula and Klebsormidium. Despite the presence of high concentrations of dissolved metals (e.g., Al and Zn) and deposits of iron hydroxide in some of the streams studied, pH was the most important determinant of the observed differences in bacterial community variability. These findings confirm that any restoration activities in such systems must focus on dealing with pH as the first priority.

scholarly journals Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

2013 ◽  
Vol 10 (4) ◽  
pp. 2747-2759 ◽  
Author(s):  
E. Ortega-Retuerta ◽  
F. Joux ◽  
W. H. Jeffrey ◽  
J. F. Ghiglione
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
16S Rrna ◽  
Surface Waters ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Canadian Arctic ◽  
Beaufort Sea ◽  
Free Living ◽  
Open Sea

Abstract. We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea in the Canadian Arctic Ocean, with a particular focus on free-living (FL) vs. particle-attached (PA) communities. Capillary electrophoresis–single-strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between PA and FL bacterial community structure in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (a proxy of dissolved organic carbon and chromophoric dissolved organic matter), suspended particles, amino acids and chlorophyll a. Pyrosequencing of 16S rRNA genes from selected samples confirmed significant differences between river, coastal and sea samples. The PA fraction was only different (15.7% similarity) from the FL one in the open sea sample. Furthermore, PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, for the coast and river samples and both PA and FL fractions, Betaproteobacteria, Alphaproteobacteria and Actinobacteria were dominant. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also serve as a basis to predict further changes in bacterial communities should climate change lead to further increases in river discharge and related particle loads.

scholarly journals Influence of hydrological factors on bacterial community structure in a tropical monsoonal estuary in India

2021 ◽  
Author(s):  
Parvathi Ammini ◽  
Michela R Catena ◽  
Jasna Vijayan ◽  
Nikhil Phadke ◽  
Nikhita Gogate
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Salinity Gradient ◽  
Pearson Correlation ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
Physico Chemical ◽  
The Impact

Abstract In the present study, we analysed variations in bacterial community structure along a salinity gradient in a tropical monsoonal estuary (Cochin estuary, CE), on the southwest coast of India, using Illumina next-generation sequencing (NGS). Water samples were collected from eight different locations thrice a year, to assess the variability in the bacterial community structure and to determine the physico-chemical factors influencing the bacterial diversity. Proteobacteria was the most dominant phyla in the estuary followed by Bacteroidetes, Cyanobacteria, Actinobacteria, and Firmicutes. Statistical analysis indicated significant variations in bacterial communities between freshwater, mesohaline and euryhaline regions, as well as between the monsoon (wet) and non-monsoon (dry) periods. Non-metric multidimensional scaling (NMDS) analysis demonstrated that the bacterial communities cluster according to different salinity regimes of the estuary. Canonical Correspondence analysis (CCA) showed a clear spatial and temporal variation in the distribution of bacterial communities in the CE. Abundance of Betaproteobacteria was high in the freshwater regions, while Gammaproteobacteria, Alphaproteobacteria and Epsilonproteobactera were more abundant in mesohaline and euryhaline regions of the estuary. Correlagram based on Pearson correlation analysis demonstrated the impact of different physico-chemical variables on the distribution of dominant phyla, class and genera. Spatial and temporal variations in bacterial community structure could be due to regional variations in environmental conditions imparted by allochthonous inputs, monsoonal rainfall, and tidal influence.

scholarly journals Abiotic environmental factors override phytoplankton succession in shaping both free-living and attached bacterial communities in a highland lake

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Huan Wang ◽  
Rong Zhu ◽  
Xiaolin Zhang ◽  
Yun Li ◽  
Leyi Ni ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Bacterial Community ◽  
Species Composition ◽  
Community Composition ◽  
Bacterial Communities ◽  
Phytoplankton Community ◽  
Bacterial Community Composition ◽  
Free Living ◽  
The Impact ◽  
Abiotic Environmental Factors

Abstract Bacterial communities are an important part of biological diversity and biogeochemical cycling in aquatic ecosystems. In this study, the relationship amongst the phytoplankton species composition and abiotic environmental factors on seasonal changes in the community composition of free-living and attached bacteria in Lake Erhai were studied. Using Illumina high-throughput sequencing, we found that the impact of environmental factors on both the free-living and attached bacterial community composition was greater than that of the phytoplankton community, amongst which total phosphorus, Secchi disk, water temperature, dissolved oxygen and conductivity strongly influenced bacterial community composition. Microcystis blooms associated with subdominant Psephonema occurred during the summer and autumn, and Fragilaria, Melosira and Mougeotia were found at high densities in the other seasons. Only small numbers of algal species-specific bacteria, including Xanthomonadaceae (Proteobacteria) and Alcaligenaceae (Betaproteobacteria), were tightly coupled to Microcystis and Psephonema during Microcystis blooms. Redundancy analysis showed that although the composition of the bacterial communities was controlled by species composition mediated by changes in phytoplankton communities and abiotic environmental factors, the impact of the abiotic environment on both free-living and attached bacterial community compositions were greater than the impact of the phytoplankton community. These results suggest that the species composition of both free-living and attached bacterial communities are affected by abiotic environmental factors, even when under strong control by biotic factors, particularly dominant genera of Microcystis and Psephonema during algal blooms.

scholarly journals The capacity of wastewater treatment plants drives bacterial community structure and its assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
Activated Sludge ◽  
Community Assembly ◽  
Bacterial Communities ◽  
Wastewater Treatment Plants ◽  
High Capacity ◽  
Operating Conditions ◽  
Rrna Gene

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

scholarly journals Effects of Plastic Debris on the Biofilm Bacterial Communities in Lake Water

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1465
Author(s):  
Chao Shen ◽  
Liuyan Huang ◽  
Guangwu Xie ◽  
Yulai Wang ◽  
Zongkai Ma ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Diversity Index ◽  
Plastic Substrate ◽  
Simpson Index ◽  
Plastic Debris ◽  
Plastic Substrates ◽  
Wiener Diversity Index

Increasing discharge of plastic debris into aquatic ecosystems and the worsening ecological risks have received growing attention. Once released, plastic debris could serve as a new substrate for microbes in waters. The complex relationship between plastics and biofilms has aroused great interest. To confirm the hypothesis that the presence of plastic in water affects the composition of biofilm in natural state, in situ biofilm culture experiments were conducted in a lake for 40 days. The diversity of biofilm attached on natural (cobble stones (CS) and wood) and plastic substrates (Polyethylene terephthalate (PET) and Polymethyl methacrylate (PMMA)) were compared, and the community structure and composition were also analyzed. Results from high-throughput sequencing of 16S rRNA showed that the diversity and species richness of biofilm bacterial communities on natural substrate (observed species of 1353~1945, Simpson index of 0.977~0.989 and Shannon–Wiener diversity index of 7.42~8.60) were much higher than those on plastic substrates (observed species of 900~1146, Simpson index of 0.914~0.975 and Shannon–Wiener diversity index of 5.47~6.99). The NMDS analyses were used to confirm the taxonomic significance between different samples, and Anosim (p = 0.001, R = 0.892) and Adonis (p = 0.001, R = 808, F = 11.19) demonstrated that this classification was statistically rigorous. Different dominant bacterial communities were found on plastic and natural substrates. Alphaproteobacterial, Betaproteobacteria and Synechococcophycideae dominated on the plastic substrate, while Gammaproteobacteria, Phycisphaerae and Planctomycetia played the main role on the natural substrates. The bacterial community structure of the two substrates also showed significant difference which is consistent with previous studies using other polymer types. Our results shed light on the fact that plastic debris can serve as a new habitat for biofilm colonization, unlike natural substrates, pathogens and plastic-degrading microorganisms selectively attached to plastic substrates, which affected the bacterial community structure and composition in aquatic environment. This study provided a new insight into understanding the potential impacts of plastics serving as a new habitat for microbial communities in freshwater environments. Future research should focus on the potential impacts of plastic-attached biofilms in various aquatic environments and the whole life cycle of plastics (i.e., from plastic fragments to microplastics) and also microbial flock characteristics using microbial plastics in the natural environment should also be addressed.

Tu1716 Evaluation of the Impact of Different Commercially Available DNA Extraction Kits and Laboratories for Assessing Bacterial Community Structure in Fecal Samples - Implications for IBD Research

2013 ◽  
Vol 144 (5) ◽  
pp. S-829
Author(s):  
Nicholas A. Kennedy ◽  
Alan Walker ◽  
UK IBD Microbiota Consortia ◽  
UK IBD Genetics Consortia ◽  
Susan H. Berry ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Dna Extraction ◽  
Bacterial Community Structure ◽  
Fecal Samples ◽  
The Impact
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