Impact of Soil Microbes and Oxygen Availability on Bacterial Community Structure of Decomposing Poultry Carcasses

The impact of soil with an intact microbial community and oxygen availability on moisture content, soil pH, and bacterial communities during decomposition of poultry carcasses was investigated. Poultry carcasses were decomposed in soil with or without a microbial community, under aerobic or anaerobic conditions. The samples collected in each microcosm burial set-up were analyzed by targeted 16S rRNA amplicon sequencing and Amplicon sequence variants (ASV) method. Our results showed that moisture was high in the burial set-ups under anaerobic conditions and pH was high in the burial set-ups under aerobic conditions. Meanwhile, the Chao1 and Shannon index significantly differed between the different burial set-ups and across different time points. In addition, bacterial taxa composition during the early period of decomposition differed from that of the late period. A total of 23 phyla, 901 genera, and 1992 species were identified. Firmicutes was the most dominant phyla in all burial set-ups throughout the decomposition. At day 60, Pseudogracilibacillus was dominant in the burial set-ups under aerobic conditions, while Lentibacillus dominated in the burial set-ups under anaerobic conditions. This study demonstrated that the soil microbial community and availability of oxygen significantly affected the changes in moisture content, pH, and bacterial composition during the decomposition process.

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Evaluation of the microbial community structure of potable water samples from occupied and unoccupied buildings using16S rRNA amplicon sequencing

10.1101/2020.07.17.209346 ◽

2020 ◽

Author(s):

Kimothy L Smith ◽

Howard A Shuman ◽

Douglas Findeisen

Keyword(s):

Microbial Community ◽

16S Rrna ◽

Water Samples ◽

Ad Hoc ◽

Microbial Community Composition ◽

Amplicon Sequencing ◽

The Other ◽

Water Usage ◽

16S Rrna Amplicon Sequencing ◽

Oxford Nanopore

AbstractWe conducted two studies of water samples from buildings with normal occupancy and water usage compared to water from buildings that were unoccupied with little or no water usage due to the COVID-19 shutdown. Study 1 had 52 water samples obtained ad hoc from buildings in four metropolitan locations in different states in the US and a range of building types. Study 2 had 36 water samples obtained from two buildings in one metropolitan location with matched water sample types. One of the buildings had been continuously occupied, and the other substantially vacant for approximately 3 months. All water samples were analyzed using 16S rRNA amplicon sequencing with a MinION from Oxford Nanopore Technologies. More than 127 genera of bacteria were identified, including genera with members that are known to include more than 50 putative frank and opportunistic pathogens. While specific results varied among sample locations, 16S rRNA amplicon abundance and the diversity of bacteria were higher in water samples from unoccupied buildings than normally occupied buildings as was the abundance of sequenced amplicons of genera known to include pathogenic bacterial members. In both studies Legionella amplicon abundance was relatively small compared to the abundance of the other bacteria in the samples. Indeed, when present, the relative abundance of Legionella amplicons was lower in samples from unoccupied buildings. Legionella did not predominate in any of the water samples and were found, on average, in 9.6% of samples in Study 1 and 8.3% of samples in Study 2.SynopsisComparison of microbial community composition in the plumbing of occupied and unoccupied buildings during the COVID-19 pandemic shutdown.

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In vivo cycling of the Escherichia coli transcription factor FNR between active and inactive states

Microbiology ◽

10.1099/mic.0.28253-0 ◽

2005 ◽

Vol 151 (12) ◽

pp. 4063-4070 ◽

Cited By ~ 29

Author(s):

David P. Dibden ◽

Jeffrey Green

Keyword(s):

Escherichia Coli ◽

De Novo ◽

Oxygen Availability ◽

Anaerobic Conditions ◽

Aerobic Conditions ◽

Fnr Protein ◽

Transcription Regulators ◽

Aerobic And Anaerobic ◽

Aerobic And Anaerobic Conditions

FNR proteins are transcription regulators that sense changes in oxygen availability via assembly–disassembly of [4Fe–4S] clusters. The Escherichia coli FNR protein is present in bacteria grown under aerobic and anaerobic conditions. Under aerobic conditions, FNR is isolated as an inactive monomeric apoprotein, whereas under anaerobic conditions, FNR is present as an active dimeric holoprotein containing one [4Fe–4S] cluster per subunit. It has been suggested that the active and inactive forms of FNR are interconverted in vivo, or that iron–sulphur clusters are mostly incorporated into newly synthesized FNR. Here, experiments using a thermo-inducible fnr expression plasmid showed that a model FNR-dependent promoter is activated under anaerobic conditions by FNR that was synthesized under aerobic conditions. Immunoblots suggested that FNR was more prone to degradation under aerobic compared with anaerobic conditions, and that the ClpXP protease contributes to this degradation. Nevertheless, FNR was sufficiently long lived (half-life under aerobic conditions, ∼45 min) to allow cycling between active and inactive forms. Measuring the abundance of the FNR-activated dms transcript when chloramphenicol-treated cultures were switched between aerobic and anaerobic conditions showed that it increased when cultures were switched to anaerobic conditions, and decreased when aerobic conditions were restored. In contrast, measurement of the abundance of the FNR-repressed ndh transcript under the same conditions showed that it decreased upon switching to anaerobic conditions, and then increased when aerobic conditions were restored. The abundance of the FNR- and oxygen-independent tatE transcript was unaffected by changes in oxygen availability. Thus, the simplest explanation for the observations reported here is that the FNR protein can be switched between inactive and active forms in vivo in the absence of de novo protein synthesis.

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Deconstructing the Soil Microbiome into Reduced-Complexity Functional Modules

mBio ◽

10.1128/mbio.01349-20 ◽

2020 ◽

Vol 11 (4) ◽

Author(s):

Dan Naylor ◽

Sarah Fansler ◽

Colin Brislawn ◽

William C. Nelson ◽

Kirsten S. Hofmockel ◽

...

Keyword(s):

Amplicon Sequencing ◽

Low Complexity ◽

Soil Extract ◽

Soil Microbiome ◽

Functional Modules ◽

Anaerobic Conditions ◽

Metabolic Potential ◽

16S Rrna Amplicon Sequencing ◽

Alternative Approach ◽

Reduced Complexity

ABSTRACT The soil microbiome represents one of the most complex microbial communities on the planet, encompassing thousands of taxa and metabolic pathways, rendering holistic analyses computationally intensive and difficult. Here, we developed an alternative approach in which the complex soil microbiome was broken into components (“functional modules”), based on metabolic capacities, for individual characterization. We hypothesized that reproducible, low-complexity communities that represent functional modules could be obtained through targeted enrichments and that, in combination, they would encompass a large extent of the soil microbiome diversity. Enrichments were performed on a starting soil inoculum with defined media based on specific carbon substrates, antibiotics, alternative electron acceptors under anaerobic conditions, or alternative growing conditions reflective of common field stresses. The resultant communities were evaluated through 16S rRNA amplicon sequencing. Less permissive modules (anaerobic conditions, complex polysaccharides, and certain stresses) resulted in more distinct community profiles with higher richness and more variability between replicates, whereas modules with simple substrates were dominated by fewer species and were more reproducible. Collectively, approximately 27% of unique taxa present in the liquid soil extract control were found across functional modules. Taxa that were underrepresented or undetected in the source soil were also enriched across the modules. Metatranscriptomic analyses were carried out on a subset of the modules to investigate differences in functional gene expression. These results demonstrate that by dissecting the soil microbiome into discrete components it is possible to obtain a more comprehensive view of the soil microbiome and its biochemical potential than would be possible using more holistic analyses. IMPORTANCE The taxonomic and functional diversity inherent to the soil microbiome complicate assessments of the metabolic potential carried out by the community members. An alternative approach is to break down the soil microbiome into reduced-complexity subsets based on metabolic capacities (functional modules) prior to sequencing and analysis. Here, we demonstrate that this approach successfully identified specific phylogenetic and biochemical traits of the soil microbiome that otherwise remained hidden from a more top-down analysis.

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H. pylori Eradication Treatment Alters Gut Microbiota and GLP-1 Secretion in Humans

Journal of Clinical Medicine ◽

10.3390/jcm8040451 ◽

2019 ◽

Vol 8 (4) ◽

pp. 451 ◽

Cited By ~ 11

Author(s):

Isabel Cornejo-Pareja ◽

Gracia Martín-Núñez ◽

M. Roca-Rodríguez ◽

Fernando Cardona ◽

Leticia Coin-Aragüez ◽

...

Keyword(s):

Microbial Community ◽

Gut Microbiota ◽

Carbohydrate Metabolism ◽

Eradication Therapy ◽

Amplicon Sequencing ◽

Antibiotic Use ◽

Metabolic Disturbances ◽

Bifidobacterium Adolescentis ◽

16S Rrna Amplicon Sequencing ◽

H Pylori

Changes in the intestinal microbial community and some metabolic disturbances, including obesity and type2 diabetes, are related. Glucagon-like peptide-1 (GLP-1) regulates glucose homeostasis. Microbiota have been linked to incretin secretion. Antibiotic use causes changes in microbial diversity and composition. Our aim was to evaluate the relationship between microbiota changes and GLP-1 secretion. A prospective case-control study with a Helicobacter pylori-positive patient model involving subjects under eradication therapy (omeprazole, clarithromycin, and amoxicillin). Forty patients with H. pylori infection and 20 matched participants, but negative for H. pylori antigen. Patients were evaluated before and two months after treatment. We analyzed anthropometric measurements, carbohydrate metabolism, lipid profile, and C-reactive protein. Gut microbiota composition was analyzed through 16S rRNA amplicon sequencing (IlluminaMiSeq). Eradication treatment for H. pylori decreased bacterial richness (Chao1, p = 0.041). Changes in gut microbiota profiles were observed at phylum, family, genus and species levels. GLP-1 secretion and variables of carbohydrate metabolism were improved. Correlations were seen between GLP-1 changes and variations within microbial community abundances, specifically Bifidobacterium adolescentis, the Lachnobacterium genus, and Coriobacteriaceae family. A conventional treatment to eradicate H. pylori could improve carbohydrate metabolism possibly in relation with an increase in GLP-1 secretion. GLP-1 secretion may be related to alterations in intestinal microbiota, specifically Lachnobacterium, B. adolescentis and Coriobacteriaceae.

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Hill-based Dissimilarity Indices and Null Models for Analysis of Microbial Community Assembly

10.21203/rs.3.rs-33130/v1 ◽

2020 ◽

Author(s):

Oskar Modin ◽

Raquel Liebana ◽

Soroush Saheb-Alam ◽

Britt-Marie Wilén ◽

Carolina Suarez ◽

...

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Community Assembly ◽

Null Model ◽

Amplicon Sequencing ◽

Null Models ◽

Marker Genes ◽

Experimental Systems ◽

Microbial Community Assembly ◽

The Impact

Abstract Background: High-throughput amplicon sequencing of marker genes, such as the 16S rRNA gene in Bacteria and Archaea, provides a wealth of information about the composition of microbial communities. To quantify differences between samples and draw conclusions about factors affecting community assembly, dissimilarity indices are typically used. However, results are subject to several biases and data interpretation can be challenging. The Jaccard and Bray-Curtis indices, which are often used to quantify taxonomic dissimilarity, are not necessarily the most logical choices. Instead, we argue that Hill-based indices, which make it possible to systematically investigate the impact of relative abundance on dissimilarity, should be used for robust analysis of data. In combination with a null model, mechanisms of microbial community assembly can be analyzed. Here, we also introduce a new software, qdiv, which enables rapid calculations of Hill-based dissimilarity indices in combination with null models.Results: Using amplicon sequencing data from two experimental systems, aerobic granular sludge (AGS) reactors and microbial fuel cells (MFC), we show that the choice of dissimilarity index can have considerable impact on results and conclusions. High dissimilarity between replicates because of random sampling effects make incidence-based indices less suited for identifying differences between groups of samples. Determining a consensus table based on count tables generated with different bioinformatic pipelines reduced the number of low-abundant, potentially spurious amplicon sequence variants (ASVs) in the data sets, which led to lower dissimilarity between replicates. Analysis with a combination of Hill-based indices and a null model allowed us to show that different ecological mechanisms acted on different fractions of the microbial communities in the experimental systems.Conclusions: Hill-based indices provide a rational framework for analysis of dissimilarity between microbial community samples. In combination with a null model, the effects of deterministic and stochastic community assembly factors on taxa of different relative abundances can be systematically investigated. Calculations of Hill-based dissimilarity indices in combination with a null model can be done in qdiv, which is freely available as a Python package (https://github.com/omvatten/qdiv). In qdiv, a consensus table can also be determined from several count tables generated with different bioinformatic pipelines.

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Anaerobic conditions unmask antimicrobial resistance

10.1101/2021.06.26.450051 ◽

2021 ◽

Author(s):

Ashton Creasy-Marrazzo ◽

Morteza M. Saber ◽

Manasi Kamat ◽

Laura S. Bailey ◽

Firdausi Qadri ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Association Studies ◽

Anaerobic Respiration ◽

Anaerobic Growth ◽

Genome Wide Association Studies ◽

Anaerobic Conditions ◽

Aerobic Conditions ◽

Minimal Inhibitory Concentrations ◽

Genome Wide ◽

The Impact

Antimicrobial resistance (AMR) in Gram negative enteropathogens is an urgent threat to the antibiotic formulary. These taxa undergo anaerobic respiration within the host, yet little is known about how anaerobic conditions influence antimicrobial resistance (AMR). The facultative enteropathogen Vibrio cholerae was chosen as a model to determine the impact of anaerobic growth on AMR because cholera is one of the few non-invasive diarrhoeal diseases for which antibiotics are indicated, albeit conditionally. V. cholerae isolates from a single outbreak were tested for resistance by minimal inhibitory concentrations (MIC) under aerobic and anaerobic conditions against clinically relevant antibiotics. Here we show that the odds of classifying isolates as resistant under anaerobic compared to aerobic conditions increased over 20 times for ciprofloxacin and 50 times for azithromycin, yet for doxycycline, all isolates remained below the breakpoint for resistance. Genome-wide association studies (GWAS) found significant associations between known and unknown genetic elements and AMR phenotypes that varied by oxygen exposure and antibiotic concentrations. In most cases, AMR phenotypes were more heritable, and more genes significantly associated with AMR were discovered, under anaerobic conditions compared to aerobic conditions. These findings challenge the paradigm of testing facultative enteropathogens for AMR under aerobic conditions alone. This experimental approach establishes a new, more sensitive framework to track and investigate mechanisms of AMR.

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Deciphering the Influence of Multiple Anthropogenic Inputs on Taxonomic and Functional Profiles of the Microbial Communities in Yitong River, Northeast China

10.21203/rs.3.rs-729563/v1 ◽

2021 ◽

Author(s):

Ying Zhang ◽

Yang Huo ◽

Zhiruo Zhang ◽

Suiyi Zhu ◽

Wei Fan ◽

...

Keyword(s):

Microbial Communities ◽

Northeast China ◽

Environmental Changes ◽

Quantitative Polymerase Chain Reaction ◽

Amplicon Sequencing ◽

Fecal Indicator ◽

16S Rrna Amplicon Sequencing ◽

Anthropogenic Inputs ◽

Wwtp Effluent ◽

The Impact

Abstract We conducted physicochemical parameters analysis, 16S rRNA amplicon sequencing and real-time quantitative polymerase chain reaction to explore the impact of human inputs on the bacterioplankton communities within a tributary of the largest river flowing through a megacity in northeast China. Agriculture largely accounted for the alteration of diversity and functions of the microbial communities. Furthermore, nutrients were significantly declined at the reservoir outlet, and WWTP effluent discharge caused changes in the river microbial community. NH3-N and NO3--N were the main environmental factors that drive the shift of the bacteria community, and rare taxa played a more important role in the response to environmental changes compared with the abundant ones. The occurrence of the human-specific fecal indicator was mostly derived from agriculture, and its increase in relative abundance was observed in the effluent. Thus, our study provides guidance for ecological assessment and management of rivers by revealing the response pattern of river bacterioplankton to multiple types of anthropogenic stressors.

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To rarefy or not to rarefy: Enhancing microbial community analysis through next-generation sequencing

10.1101/2020.09.09.290049 ◽

2020 ◽

Author(s):

Ellen S. Cameron ◽

Philip J. Schmidt ◽

Benjamin J.-M. Tremblay ◽

Monica B. Emelko ◽

Kirsten M. Müller

Keyword(s):

Microbial Community ◽

Community Analysis ◽

Amplicon Sequencing ◽

Microbial Community Analysis ◽

List Type ◽

Sequencing Data ◽

Water And Wastewater Treatment ◽

Library Size ◽

Size Selection ◽

The Impact

AbstractThe application of amplicon sequencing in water research provides a rapid and sensitive technique for microbial community analysis in a variety of environments ranging from freshwater lakes to water and wastewater treatment plants. It has revolutionized our ability to study DNA collected from environmental samples by eliminating the challenges associated with lab cultivation and taxonomic identification. DNA sequencing data consist of discrete counts of sequence reads, the total number of which is the library size. Samples may have different library sizes and thus, a normalization technique is required to meaningfully compare them. The process of randomly subsampling sequences to a selected normalized library size from the sample library—rarefying—is one such normalization technique. However, rarefying has been criticized as a normalization technique because data can be omitted through the exclusion of either excess sequences or entire samples, depending on the rarefied library size selected. Although it has been suggested that rarefying should be avoided altogether, we propose that repeatedly rarefying enables (i) characterization of the variation introduced to diversity analyses by this random subsampling and (ii) selection of smaller library sizes where necessary to incorporate all samples in the analysis. Rarefying may be a statistically valid normalization technique, but researchers should evaluate their data to make appropriate decisions regarding library size selection and subsampling type. The impact of normalized library size selection and rarefying with or without replacement in diversity analyses were evaluated herein.Highlights▪ Amplicon sequencing technology for environmental water samples is reviewed▪ Sequencing data must be normalized to allow comparison in diversity analyses▪ Rarefying normalizes library sizes by subsampling from observed sequences▪ Criticisms of data loss through rarefying can be resolved by rarefying repeatedly▪ Rarefying repeatedly characterizes errors introduced by subsampling sequences

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The impact of bacterial diversity on resistance to biocides in oilfields

Scientific Reports ◽

10.1038/s41598-021-02494-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Gabriela Feix Pereira ◽

Harry Luiz Pilz-Junior ◽

Gertrudes Corção

Keyword(s):

Water Samples ◽

Produced Water ◽

Functional Characterization ◽

Amplicon Sequencing ◽

Oil Field ◽

Oil Fields ◽

Sulfate Reducing ◽

16S Rrna Amplicon Sequencing ◽

Dimethyl Benzyl ◽

The Impact

AbstractExtreme conditions and the availability of determinate substrates in oil fields promote the growth of a specific microbiome. Sulfate-reducing bacteria (SRB) and acid-producing bacteria (APB) are usually found in these places and can harm important processes due to increases in corrosion rates, biofouling and reservoir biosouring. Biocides such as glutaraldehyde, dibromo-nitrilopropionamide (DBNPA), tetrakis (hydroxymethyl) phosphonium sulfate (THPS) and alkyl dimethyl benzyl ammonium chloride (ADBAC) are commonly used in oil fields to mitigate uncontrolled microbial growth. The aim of this work was to evaluate the differences among microbiome compositions and their resistance to standard biocides in four different Brazilian produced water samples, two from a Southeast Brazil offshore oil field and two from different Northeast Brazil onshore oil fields. Microbiome evaluations were carried out through 16S rRNA amplicon sequencing. To evaluate the biocidal resistance, the Minimum Inhibitory Concentration (MIC) of the standard biocides were analyzed using enriched consortia of SRB and APB from the produced water samples. The data showed important differences in terms of taxonomy but similar functional characterization, indicating the high diversity of the microbiomes. The APB and SRB consortia demonstrated varying resistance levels against the biocides. These results will help to customize biocidal treatments in oil fields.

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Localization of bacterial communities within gut compartments across Cephalotes turtle ants

Applied and Environmental Microbiology ◽

10.1128/aem.02803-20 ◽

2021 ◽

Author(s):

Peter J. Flynn ◽

Catherine L. D’Amelio ◽

Jon G. Sanders ◽

Jacob A. Russell ◽

Corrie S. Moreau

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Digestive Tract ◽

Bacterial Communities ◽

Evolutionary History ◽

Amplicon Sequencing ◽

Caste Differentiation ◽

Animal Group ◽

16S Rrna Amplicon Sequencing ◽

Host Phylogeny

Microbial communities within the animal digestive tract often provide important functions for their hosts. The composition of eukaryotes' gut bacteria can be shaped by host diet, vertical bacterial transmission, and physiological variation within the digestive tract. In several ant taxa, recent findings have demonstrated that nitrogen provisioning by symbiotic bacteria makes up for deficiencies in herbivorous diets. Using 16S rRNA amplicon sequencing and qPCR, this study examined bacterial communities at a fine scale across one such animal group, the turtle ant genus Cephalotes. We analyzed the composition and colonization density across four portions of the digestive tract to understand how bacterial diversity is structured across gut compartments, potentially allowing for specific metabolic functions of benefit to the host. In addition, we aimed to understand if caste differentiation or host relatedness influences the gut bacterial communities of Cephalotes ants. Microbial communities were found to vary strongly across Cephalotes gut compartments in ways that transcend both caste and host phylogeny. Despite this, caste and host phylogeny still have detectable effects. We demonstrated microbial community divergence across gut compartments, possibly due to the varying function of each gut compartment for digestion. IMPORTANCE Gut compartments play an important role in structuring the microbial community within individual ants. The gut chambers of the turtle ant digestive tract differ remarkably in symbiont abundance and diversity. Furthermore, caste type explains some variation in the microbiome composition. Finally, the evolutionary history of the Cephalotes species structures the microbiome in our study, which elucidates a trend in which related ants maintain related microbiomes, conceivably owing to co-speciation. Amazingly, gut compartment-specific signatures of microbial diversity, relative abundance, composition, and abundance have been conserved over Cephalotes evolutionary history, signifying that this symbiosis has been largely stable for over 50 million years.

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