Microbial Community Cohesion Mediates Community Turnover in Unperturbed Aquifers

ABSTRACT Microbial ecological processes are frequently studied in the presence of perturbations rather than in undisturbed environments, despite the relatively stable conditions dominating many microbial habitats. To examine processes influencing microbial community structuring in the absence of strong external perturbations, three unperturbed aquifers in Ohio (Greene, Licking, and Athens) were sampled over 2 years and analyzed using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling. Redox conditions ranging from highly reducing to more oxidizing distinguished aquifer geochemistry across the three locations. Distinct microbial communities were present in each aquifer, and overall community structure was related to geochemistry, although community composition was more similar between the Athens and Licking locations. The ecological processes acting upon microbial assemblages within aquifers were varied; geochemical changes affected the Athens location, while time or some unknown factor affected Greene County. Stochastic processes, however, dominated the Licking aquifer, suggesting a decoupling between environmental fluctuations and community development. Although physicochemical differences might be expected to drive variable selection, dispersal limitation (inability to mix) explained differences between Athens and Licking. Finally, community complexity as measured by “cohesion” indicated that less-interconnected communities experienced higher turnover and were more likely to be affected by stochastic processes. Conversely, more-interconnected communities experienced lower turnover and susceptibility to homogenizing selection. Based upon these data, we support the hypothesis that unperturbed environments house dynamic microbial communities due to external and internal forces. IMPORTANCE Many microbial ecology studies have examined community structuring processes in dynamic or perturbed situations, while stable environments have been investigated to a lesser extent. Researchers have predicted that environmental communities never truly reach a steady state but rather exist in states of constant flux due to internal, rather than external, dynamics. The research presented here utilized a combined null model approach to examine the deterministic and stochastic processes responsible for observed community differences in unperturbed, groundwater ecosystems. Additionally, internal dynamics were investigated by relating a recently published measure of community complexity (cohesion) to ecological structuring processes. The data presented here suggest that communities that are more cohesive, and therefore more complex, are more likely affected by homogenizing selection, while less-complex communities are more susceptible to dispersal. By understanding the relationship between internal dynamics and community structuring processes, insight about microbial population development in natural systems can be obtained.

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69 The ability of an artificial sweetener (Sucram®) to influence microbial community structure in the rumen papillae and content through the production of microbial-based neurochemicals

Journal of Animal Science ◽

10.1093/jas/skz258.208 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 100-101

Author(s):

Mark Lyte ◽

Lucas Koester ◽

Stephan Schmitz-Esser

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Ex Vivo ◽

16S Rrna Gene Sequencing ◽

Rumen Content ◽

Rrna Gene ◽

Artificial Sweetener ◽

Rumen Microbes ◽

Host Physiology ◽

Methane Reduction

Abstract The study of microorganisms to produce and utilize neurochemical signaling molecules that interact with the host is the emerging field known as microbial endocrinology. Production of these molecules can be regulated by several different environmental factors, including diet. The effect of artificial sweeteners on ruminant gastrointestinal tract microbiota and the ability of individual members to produce neurochemicals that may determine community composition and affect host physiology are unknown. To analyze whether an artificial sweetener (Sucram®, Pancosma, Switzerland) affects rumen content (RC) and rumen papillae (RP) microbiota, six fistulated, lactating Holstein cows were sampled before (baseline) and after exposure to Sucram®. 16S rRNA gene sequencing was conducted to identify Sucram®-induced microbial community changes. Additionally, ex vivo microbial cultures were used to identify neurochemical production in RP bacteria. Exposure to Sucram significantly increased the abundance of Operational Taxonomic Units (OTUs) belonging to Ruminobacter, Prevotella, Sharpea, Ruminococcus and Rikenella on the RP. These organisms have been reported to aid in digestion of feedstuffs and methane reduction, suggesting that Sucram® may induce beneficial shifts in rumen microbial communities. To gain preliminary insight into neurochemical production of RP microorganisms, we tested four different Lactobacillus isolates from RP for neurochemical production. We observed that the neurochemicals DOPAC (3,4-Dihydroxyphenylacetic acid) and L-DOPA (L-3,4-dihydroxyphenylalanine) were produced by three and four isolates, respectively. Ongoing experiments are evaluating the effects of Sucram® on neurochemical production in a larger number of rumen microbes. Overall, we observed significant differences in OTU abundance in response to the addition of Sucram®. Additionally, we confirmed that RP bacteria can produce neurochemicals. Both of these results are key to understanding how Sucram® modifies microbial communities within the rumen and possibly influences host physiology. Research into microbial endocrinology-based neurochemical signaling between rumen microbiota and their animal hosts may lead to advancement of livestock feed efficiency and welfare.

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Dynamic and Assembly of Benthic Bacterial Community in an Industrial-Scale In-Pond Raceway Recirculating Culture System

Frontiers in Microbiology ◽

10.3389/fmicb.2021.797817 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yiran Hou ◽

Bing Li ◽

Gangchun Xu ◽

Da Li ◽

Chengfeng Zhang ◽

...

Keyword(s):

Bacterial Community ◽

Stochastic Processes ◽

Microbial Communities ◽

Bacterial Communities ◽

Culture System ◽

Null Model ◽

Dispersal Limitation ◽

Industrial Scale ◽

Ecological Processes ◽

Benthic Microbial Communities

To reduce water utilization, limit environmental pollution, and guarantee aquatic production and quality, the in-pond raceway recirculating culture system (IPRS) has been developed and is widely used. The effectiveness and sustainability of IPRSs rely on a good understanding of the ecological processes related to bacterial communities in the purification area. In this study, we investigated the dynamics and assembly mechanisms of benthic bacterial communities in the purification area of an industrial-scale IRPS. We found significant temporal and spatial variations in the sediment characteristics and benthic bacterial communities of the IPRS, although correlation analyses revealed a very limited relationship between them. Among the different culture stages, we identified numerous benthic bacteria with different abundances. Abundances of the phyla Bacteroidota and Desulfobacterota decreased whereas those of Myxococcota and Gemmatimonadota increased as the culture cycle progressed. Co-occurrence networks revealed that the bacterial community was less complex but more stable in the IPRS at the final stage compared with the initial stage. The neutral community model (NCM) showed that stochastic processes were the dominant ecological processes shaping the assembly of the benthic bacterial community. The null model suggested that homogenizing dispersal was more powerful than dispersal limitation and drift in regulating the assembly of the community. These findings indicate that the benthic microbial communities in purification areas of the IPRS may not be affected by the deposited wastes, and a more stable benthic microbial communities were formed and mainly driven by stochastic processes. However, the benthic microbial communities in the purification area at the end of the culturing stage was characterized by potentially inhibited organic matter degradation and carbon and sulfur cycling abilities, which was not corresponding to the purification area’s function. From this point on, the IPRS, especially the purification area was needed to be further optimized and improved.

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Locally-adapted Mimulus ecotypes differentially impact rhizosphere bacterial and archaeal communities in an environment-dependent manner

10.1101/652883 ◽

2019 ◽

Author(s):

Alan W. Bowsher ◽

Patrick J. Kearns ◽

Damian Popovic ◽

David B. Lowry ◽

Ashley Shade

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Plant Root ◽

16S Rrna Gene Sequencing ◽

Wild Plants ◽

Rrna Gene ◽

Transplant Experiment ◽

Dependent Manner ◽

Reciprocal Transplant Experiment ◽

Soil Microbial Community Structure

AbstractPlant root-microbe interactions influence plant productivity, health, and resistance to stress. Although there is evidence that plant species and even genotypes can alter soil microbial community structure, environmental conditions can potentially outweigh plant genetic effects. Here, we used a reciprocal transplant experiment to understand the contributions of the environment and the host plant to rhizosphere microbiome composition in locally-adapted ecotypes of Mimulus guttatus (syn. Erythranthe guttata (Fisch. ex DC.) G.L. Nesom). Two genotypes of a coastal ecotype and two genotypes of an inland ecotype were planted at coastal and inland sites. After three months, we collected rhizosphere and bulk soil and assessed microbial communities by 16S rRNA gene sequencing. We found that local environment (coastal versus inland site) strongly influenced rhizosphere communities, at least in part due to distinct local microbial species pools. Host identity played a smaller role: at each site, the ecotypes exhibited remarkably similar composition of microbial communities at the class level, indicating that divergent M. guttatus ecotypes recruit phylogenetically similar rhizosphere communities, even in environments to which they are maladapted. Nevertheless, the two ecotypes significantly differed in community composition at the inland site due to an exclusive set of rare taxa associated with each ecotype. Although our results indicate that locally-adapted M. guttatus ecotypes are genetically diverged in factors shaping rhizosphere communities, environmental factors can trump genetic factors in shaping the M. guttatus microbiome. Overall, our findings demonstrate that wild plants strongly impact root-associated microbial communities, but hierarchical drivers interact to shape microbial community assembly outcomes.

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Composition of seagrass phyllosphere microbial communities suggests rapid environmental regulation of community structure

FEMS Microbiology Ecology ◽

10.1093/femsec/fiab013 ◽

2021 ◽

Author(s):

Margaret A Vogel ◽

Olivia U Mason ◽

Thomas E Miller

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Host Plant ◽

Environmental Conditions ◽

16S Rrna Gene Sequencing ◽

Rrna Gene ◽

Community Members ◽

Bacterial Phyla ◽

Primary Driver ◽

Rrna Gene Sequencing

Abstract Recent studies have revealed that seagrass blade surfaces, also known as the phyllosphere, are rich habitats for microbes; however, the primary drivers of composition and structure in these microbial communities are largely unknown. This study utilized a reciprocal transplant approach between two sites with different environmental conditions combined with 16S rRNA gene sequencing (iTag) to examine the relative influence of environmental conditions and host plant on phyllosphere community composition of the seagrass Thalassia testudinum. After thirty days, identity of phyllosphere microbial community members was more similar within the transplant sites than between despite differences in the source of host plant. Additionally, the diversity and evenness of these communities was significantly different between the two sites. These results indicated that local environmental conditions can be a primary driver in structuring seagrass phyllosphere microbial communities over relatively short time scales. Composition of microbial community members in this study also deviated from those in previous seagrass phyllosphere studies with a higher representation of candidate bacterial phyla and archaea than previously observed. The capacity for seagrass phyllosphere microbial communities to shift dramatically with environmental conditions, including ecosystem perturbations, could significantly affect seagrass-microbe interactions in ways that may influence the health of the seagrass host.

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A Comparative Study on the Microbial Communities of Rhynchophorus ferrugineus (Red Palm Weevil)-Infected and Healthy Palm Trees

Arabian Journal for Science and Engineering ◽

10.1007/s13369-021-05979-9 ◽

2021 ◽

Author(s):

N. Alshammari ◽

Meshari Alazmi ◽

Naimah A. Alanazi ◽

Abdel Moneim E. Sulieman ◽

Vajid N. Veettil ◽

...

Keyword(s):

Microbial Communities ◽

16S Rrna Gene Sequencing ◽

Rrna Gene ◽

Rhynchophorus Ferrugineus ◽

Tree Trunk ◽

Red Palm Weevil ◽

Healthy Tree ◽

Palm Trees ◽

Infected Tree ◽

Palm Weevil

AbstractSeveral studies have investigated palm trees’ microbiota infected with red palm weevil (RPW) (Rhynchophorus ferrugineus), the major pest of palm trees. This study compared the microbial communities of infected and uninfected palm trees in the Hail region, Northern Saudi Arabia, determined by high-throughput 16S rRNA gene sequencing by Illumina MiSeq. The results indicated that taxonomic diversity variation was higher for infected tree trunk than the healthy tree trunk. Soil samples from the vicinity of healthy and infected trees did not have a significant variation in bacterial diversity. Myxococcota, Acidobacteriota, and Firmicutes were the dominant phyla in RPW-infected tree trunk, and Pseudomonadaceae was the most prominent family. This study is the first report on the characterization of RPW-infected and healthy palm trees’ microbiome.

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Collection of a Bacterial Community Reconstructed from Marine Metagenomes Derived from Jinhae Bay, South Korea

Data ◽

10.3390/data6050044 ◽

2021 ◽

Vol 6 (5) ◽

pp. 44

Author(s):

Jae-Hyun Lim ◽

Il-Nam Kim

Keyword(s):

Microbial Community ◽

South Korea ◽

Microbial Communities ◽

Marine Bacteria ◽

Sampling Site ◽

Community Change ◽

Rrna Gene ◽

Water Column Stratification ◽

Metagenomics Data ◽

Jinhae Bay

Marine bacteria are known to play significant roles in marine biogeochemical cycles regarding the decomposition of organic matter. Despite the increasing attention paid to the study of marine bacteria, research has been too limited to fully elucidate the complex interaction between marine bacterial communities and environmental variables. Jinhae Bay, the study area in this work, is the most anthropogenically eutrophied coastal bay in South Korea, and while its physical and biogeochemical characteristics are well described, less is known about the associated changes in microbial communities. In the present study, we reconstructed a metagenomics data based on the 16S rRNA gene to investigate temporal and vertical changes in microbial communities at three depths (surface, middle, and bottom) during a seven-month period from June to December 2016 at one sampling site (J1) in Jinhae Bay. Of all the bacterial data, Proteobacteria, Bacteroidetes, and Cyanobacteria were predominant from June to November, whereas Firmicutes were predominant in December, especially at the middle and bottom depths. These results show that the composition of the microbial community is strongly associated with temporal changes. Furthermore, the community compositions were markedly different between the surface, middle, and bottom depths in summer, when water column stratification and bottom water hypoxia (low dissolved oxygen level) were strongly developed. Metagenomics data contribute to improving our understanding of important relationships between environmental characteristics and microbial community change in eutrophication-induced and deoxygenated coastal areas.

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Impact of Substratum Surface on Microbial Community Structure and Treatment Performance in Biological Aerated Filters

Applied and Environmental Microbiology ◽

10.1128/aem.03001-13 ◽

2013 ◽

Vol 80 (1) ◽

pp. 177-183 ◽

Cited By ~ 10

Author(s):

Lavane Kim ◽

Eulyn Pagaling ◽

Yi Y. Zuo ◽

Tao Yan

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Bacterial Species ◽

Community Analysis ◽

Microbial Community Analysis ◽

Rrna Gene ◽

Content Type ◽

Property Change ◽

And Control ◽

Start Ups

ABSTRACTThe impact of substratum surface property change on biofilm community structure was investigated using laboratory biological aerated filter (BAF) reactors and molecular microbial community analysis. Two substratum surfaces that differed in surface properties were created via surface coating and used to develop biofilms in test (modified surface) and control (original surface) BAF reactors. Microbial community analysis by 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis (DGGE) showed that the surface property change consistently resulted in distinct profiles of microbial populations during replicate reactor start-ups. Pyrosequencing of the bar-coded 16S rRNA gene amplicons surveyed more than 90% of the microbial diversity in the microbial communities and identified 72 unique bacterial species within 19 bacterial orders. Among the 19 orders of bacteria detected,BurkholderialesandRhodocyclalesof theBetaproteobacteriaclass were numerically dominant and accounted for 90.5 to 97.4% of the sequence reads, and their relative abundances in the test and control BAF reactors were different in consistent patterns during the two reactor start-ups. Three of the five dominant bacterial species also showed consistent relative abundance changes between the test and control BAF reactors. The different biofilm microbial communities led to different treatment efficiencies, with consistently higher total organic carbon (TOC) removal in the test reactor than in the control reactor. Further understanding of how surface properties affect biofilm microbial communities and functional performance would enable the rational design of new generations of substrata for the improvement of biofilm-based biological treatment processes.

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Assessing high-throughput environmental DNA extraction methods for meta-barcode characterization of aquatic microbial communities

Journal of Water and Health ◽

10.2166/wh.2018.108 ◽

2018 ◽

Vol 17 (1) ◽

pp. 37-49 ◽

Cited By ~ 6

Author(s):

Abdolrazagh Hashemi Shahraki ◽

Subba Rao Chaganti ◽

Daniel Heath

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

High Throughput ◽

Environmentally Friendly ◽

Environmental Dna ◽

Magnetic Bead ◽

Extraction Methods ◽

Environmental Research ◽

Rrna Gene

Abstract The characterization of microbial community dynamics using genomic methods is rapidly expanding, impacting many fields including medical, ecological, and environmental research and applications. One of the biggest challenges for such studies is the isolation of environmental DNA (eDNA) from a variety of samples, diverse microbes, and widely variable community compositions. The current study developed environmentally friendly, user safe, economical, and high throughput eDNA extraction methods for mixed aquatic microbial communities and tested them using 16 s rRNA gene meta-barcoding. Five different lysis buffers including (1) cetyltrimethylammonium bromide (CTAB), (2) digestion buffer (DB), (3) guanidinium isothiocyanate (GITC), (4) sucrose lysis (SL), and (5) SL-CTAB, coupled with four different purification methods: (1) phenol-chloroform-isoamyl alcohol (PCI), (2) magnetic Bead-Robotic, (3) magnetic Bead-Manual, and (4) membrane-filtration were tested for their efficacy in extracting eDNA from recreational freshwater samples. Results indicated that the CTAB-PCI and SL-Bead-Robotic methods yielded the highest genomic eDNA concentrations and succeeded in detecting the core microbial community including the rare microbes. However, our study recommends the SL-Bead-Robotic eDNA extraction protocol because this method is safe, environmentally friendly, rapid, high-throughput and inexpensive.

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Deterministic Selection Dominates Microbial Community Assembly in Termite Mounds Across a Large Spatial Area

10.21203/rs.3.rs-34782/v1 ◽

2020 ◽

Author(s):

Qing-Lin Chen ◽

Hang-Wei Hu ◽

Zhen-Zhen Yan ◽

Chao-Yu Li ◽

Bao-Anh Thi Nguyen ◽

...

Keyword(s):

Microbial Community ◽

Stochastic Processes ◽

Microbial Communities ◽

Fungal Community ◽

Community Assembly ◽

Distance Decay ◽

Termite Mounds ◽

Deterministic Processes ◽

Microbial Community Assembly

Abstract Background: Termites are ubiquitous insects in tropical and subtropical habitats, where they construct massive mounds from soil, their saliva and excreta. Termite mounds harbor an enormous amount of microbial inhabitants, which regulate multiple ecosystem functions such as mitigating methane emissions and increasing ecosystem resistance to climate change. However, we lack a mechanistic understanding about the role of termite mounds in modulating the microbial community assembly processes, which are essential to unravel the biological interactions of soil fauna and microorganisms, the major components of soil food webs. We conducted a large-scale survey across a >1500 km transect in northern Australia to investigate biogeographical patterns of bacterial and fungal community in 134 termite mounds and the relative importance of deterministic versus stochastic processes in microbial community assembly. Results: Microbial alpha (number of phylotypes) and beta (changes in bacterial and fungal community composition) significantly differed between termite mounds and surrounding soils. Microbial communities in termite mounds exhibited a significant distance-decay pattern, and fungal communities had a stronger distance-decay relationship (slope = -1.91) than bacteria (slope = -0.21). Based on the neutral community model (fitness < 0.7) and normalized stochasticity ratio index (NST) with a value below the 50% boundary point, deterministic selection, rather than stochastic forces, predominated the microbial community assembly in termite mounds. Deterministic processes exhibited significantly weaker impacts on bacteria (NST = 45.23%) than on fungi (NST = 33.72%), probably due to the wider habitat niche breadth and higher potential migration rate of bacteria. The abundance of antibiotic resistance genes (ARGs) was negatively correlated with bacterial/fungal biomass ratios, indicating that ARG content might be an important biotic factor that drove the biogeographic pattern of microbial communities in termite mounds. Conclusions: Deterministic processes play a more important role than stochastic processes in shaping the microbial community assembly in termite mounds, an unique habitat ubiquitously distributed in tropical and subtropical ecosystems. An improved understanding of the biogeographic patterns of microorganisms in termite mounds is crucial to decipher the role of soil faunal activities in shaping microbial community assembly, with implications for their mediated ecosystems functions and services.

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Dynamics of Soil Microbial Communities During Diazepam and Oxazepam Biodegradation in Soil Flooded by Water From a WWTP

Frontiers in Microbiology ◽

10.3389/fmicb.2021.742000 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marc Crampon ◽

Coralie Soulier ◽

Pauline Sidoli ◽

Jennifer Hellal ◽

Catherine Joulian ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Microbial Communities ◽

Soil Microbial Communities ◽

Gene Sequencing ◽

16S Rrna Gene Sequencing ◽

Treated Wastewater ◽

Rrna Gene ◽

Sequencing Data ◽

Rrna Gene Sequencing

The demand for energy and chemicals is constantly growing, leading to an increase of the amounts of contaminants discharged to the environment. Among these, pharmaceutical molecules are frequently found in treated wastewater that is discharged into superficial waters. Indeed, wastewater treatment plants (WWTPs) are designed to remove organic pollution from urban effluents but are not specific, especially toward contaminants of emerging concern (CECs), which finally reach the natural environment. In this context, it is important to study the fate of micropollutants, especially in a soil aquifer treatment (SAT) context for water from WWTPs, and for the most persistent molecules such as benzodiazepines. In the present study, soils sampled in a reed bed frequently flooded by water from a WWTP were spiked with diazepam and oxazepam in microcosms, and their concentrations were monitored for 97 days. It appeared that the two molecules were completely degraded after 15 days of incubation. Samples were collected during the experiment in order to follow the dynamics of the microbial communities, based on 16S rRNA gene sequencing for Archaea and Bacteria, and ITS2 gene for Fungi. The evolution of diversity and of specific operating taxonomic units (OTUs) highlighted an impact of the addition of benzodiazepines, a rapid resilience of the fungal community and an evolution of the bacterial community. It appeared that OTUs from the Brevibacillus genus were more abundant at the beginning of the biodegradation process, for diazepam and oxazepam conditions. Additionally, Tax4Fun tool was applied to 16S rRNA gene sequencing data to infer on the evolution of specific metabolic functions during biodegradation. It finally appeared that the microbial community in soils frequently exposed to water from WWTP, potentially containing CECs such as diazepam and oxazepam, may be adapted to the degradation of persistent contaminants.

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