scholarly journals Attributes of Drying Define the Structure and Functioning of Microbial Communities in Temperate Riverbed Sediment

2021 ◽  
Vol 12 ◽  
Author(s):  
José Schreckinger ◽  
Michael Mutz ◽  
Clara Mendoza-Lera ◽  
Aline Frossard
Keyword(s):  
Microbial Community ◽  
Microbial Community Composition ◽  
Community Respiration ◽  
Rrna Gene ◽  
Dry Period ◽  
Fungal Community Structure ◽  
Riverbed Sediment ◽  
Drying Treatment ◽  
Northeastern Germany ◽  
Microbial Community Assembly

Combined effects of climate change and increasing anthropogenic water demand have increased and extended dry period occurrences in rivers worldwide. Riverbed drying can significantly affect sediment microorganisms, crucial drivers of biogeochemical processes in lotic systems. In this study, we evaluated how sediment bacterial and fungal community structure and composition (based on 16S rRNA gene and ITS metabarcoding) and microbial functions (community respiration and extracellular enzymatic activities) respond to different riverbed drying intensities over 90 days. Riverbed sediment collected in a flowing reach of the Spree river in northeastern Germany was dried under different rates in outdoor mesocosms during the summer months of 2018. Our results demonstrate that drying attributes (duration and intensity) and sediment organic matter (OM) content play a crucial role in sediment microbial community assembly and functioning throughout drying. Milder drying surprisingly triggered a more rapid and drastic change in the microbial community composition and diversity. After 90 days of drying, Bacilli (Firmicutes) became the dominant bacterial class in most treatments, except in sediments with low OM content under the most severe drying treatment. Fungal amplicon sequence variants (ASVs) from Dothideomycetes (Ascomycota) had by far the highest relative abundance in all our treatments at the end of the drying experiment, making up 65.1% to 94.0% of the fungal reads. CO2 fluxes, a proxy for sediment community respiration, were rapidly and strongly affected by drying in all treatments. Our results imply that even short riverbed drying periods are likely to have significant consequences for the biogeochemical dynamics in recently formed non-perennial temperate rivers.

scholarly journals Benchmarking laboratory processes to characterise low-biomass respiratory microbiota

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Raiza Hasrat ◽  
Jolanda Kool ◽  
Wouter A. A. de Steenhuijsen Piters ◽  
Mei Ling J. N. Chu ◽  
Sjoerd Kuiling ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Positive Control ◽  
Rrna Gene ◽  
Elution Buffer ◽  
Community Profile ◽  
Microbial Community Profile ◽  
Microbial Dna ◽  
Pcr Conditions

AbstractThe low biomass of respiratory samples makes it difficult to accurately characterise the microbial community composition. PCR conditions and contaminating microbial DNA can alter the biological profile. The objective of this study was to benchmark the currently available laboratory protocols to accurately analyse the microbial community of low biomass samples. To study the effect of PCR conditions on the microbial community profile, we amplified the 16S rRNA gene of respiratory samples using various bacterial loads and different number of PCR cycles. Libraries were purified by gel electrophoresis or AMPure XP and sequenced by V2 or V3 MiSeq reagent kits by Illumina sequencing. The positive control was diluted in different solvents. PCR conditions had no significant influence on the microbial community profile of low biomass samples. Purification methods and MiSeq reagent kits provided nearly similar microbiota profiles (paired Bray–Curtis dissimilarity median: 0.03 and 0.05, respectively). While profiles of positive controls were significantly influenced by the type of dilution solvent, the theoretical profile of the Zymo mock was most accurately analysed when the Zymo mock was diluted in elution buffer (difference compared to the theoretical Zymo mock: 21.6% for elution buffer, 29.2% for Milli-Q, and 79.6% for DNA/RNA shield). Microbiota profiles of DNA blanks formed a distinct cluster compared to low biomass samples, demonstrating that low biomass samples can accurately be distinguished from DNA blanks. In summary, to accurately characterise the microbial community composition we recommend 1. amplification of the obtained microbial DNA with 30 PCR cycles, 2. purifying amplicon pools by two consecutive AMPure XP steps and 3. sequence the pooled amplicons by V3 MiSeq reagent kit. The benchmarked standardized laboratory workflow presented here ensures comparability of results within and between low biomass microbiome studies.

scholarly journals Do initial concentration and activated sludge seasonality affect pharmaceutical biotransformation rate constants?

2021 ◽  
Author(s):  
Tamara J. H. M. van Bergen ◽  
Ana B. Rios-Miguel ◽  
Tom M. Nolte ◽  
Ad M. J. Ragas ◽  
Rosalie van Zelm ◽  
...  
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Community Composition ◽  
Rate Constants ◽  
Wastewater Treatment Plants ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Initial Concentration ◽  
Different Seasons

Abstract Pharmaceuticals find their way to the aquatic environment via wastewater treatment plants (WWTPs). Biotransformation plays an important role in mitigating environmental risks; however, a mechanistic understanding of involved processes is limited. The aim of this study was to evaluate potential relationships between first-order biotransformation rate constants (kb) of nine pharmaceuticals and initial concentration of the selected compounds, and sampling season of the used activated sludge inocula. Four-day bottle experiments were performed with activated sludge from WWTP Groesbeek (The Netherlands) of two different seasons, summer and winter, spiked with two environmentally relevant concentrations (3 and 30 nM) of pharmaceuticals. Concentrations of the compounds were measured by LC–MS/MS, microbial community composition was assessed by 16S rRNA gene amplicon sequencing, and kb values were calculated. The biodegradable pharmaceuticals were acetaminophen, metformin, metoprolol, terbutaline, and phenazone (ranked from high to low biotransformation rates). Carbamazepine, diatrizoic acid, diclofenac, and fluoxetine were not converted. Summer and winter inocula did not show significant differences in microbial community composition, but resulted in a slightly different kb for some pharmaceuticals. Likely microbial activity was responsible instead of community composition. In the same inoculum, different kb values were measured, depending on initial concentration. In general, biodegradable compounds had a higher kb when the initial concentration was higher. This demonstrates that Michealis-Menten kinetic theory has shortcomings for some pharmaceuticals at low, environmentally relevant concentrations and that the pharmaceutical concentration should be taken into account when measuring the kb in order to reliably predict the fate of pharmaceuticals in the WWTP. Key points • Biotransformation and sorption of pharmaceuticals were assessed in activated sludge. • Higher initial concentrations resulted in higher biotransformation rate constants for biodegradable pharmaceuticals. • Summer and winter inocula produced slightly different biotransformation rate constants although microbial community composition did not significantly change. Graphical abstract

scholarly journals Temporal Dynamics of Cloacal Microbiota in Adult Laying Chickens With and Without Access to an Outdoor Range

2021 ◽  
Vol 11 ◽  
Author(s):  
Janneke Schreuder ◽  
Francisca C. Velkers ◽  
Alex Bossers ◽  
Ruth J. Bouwstra ◽  
Willem F. de Boer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Intestinal Microbiota ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Microbial Community Composition ◽  
Sudden Change ◽  
Rrna Gene ◽  
Poultry House ◽  
Over Time

Associations between animal health and performance, and the host’s microbiota have been recently established. In poultry, changes in the intestinal microbiota have been linked to housing conditions and host development, but how the intestinal microbiota respond to environmental changes under farm conditions is less well understood. To gain insight into the microbial responses following a change in the host’s immediate environment, we monitored four indoor flocks of adult laying chickens three times over 16 weeks, during which two flocks were given access to an outdoor range, and two were kept indoors. To assess changes in the chickens’ microbiota over time, we collected cloacal swabs of 10 hens per flock and performed 16S rRNA gene amplicon sequencing. The poultry house (i.e., the stable in which flocks were housed) and sampling time explained 9.2 and 4.4% of the variation in the microbial community composition of the flocks, respectively. Remarkably, access to an outdoor range had no detectable effect on microbial community composition, the variability of microbiota among chickens of the same flock, or microbiota richness, but the microbiota of outdoor flocks became more even over time. Fluctuations in the composition of the microbiota over time within each poultry house were mainly driven by turnover in rare, rather than dominant, taxa and were unique for each flock. We identified 16 amplicon sequence variants that were differentially abundant over time between indoor and outdoor housed chickens, however none were consistently higher or lower across all chickens of one housing type over time. Our study shows that cloacal microbiota community composition in adult layers is stable following a sudden change in environment, and that temporal fluctuations are unique to each flock. By exploring microbiota of adult poultry flocks within commercial settings, our study sheds light on how the chickens’ immediate environment affects the microbiota composition.

scholarly journals The Koala (Phascolarctos cinereus) faecal microbiome differs with diet in a wild population

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6534 ◽  
Author(s):  
Kylie L. Brice ◽  
Pankaj Trivedi ◽  
Thomas C. Jeffries ◽  
Michaela D.J. Blyton ◽  
Christopher Mitchell ◽  
...  
Keyword(s):  
Microbial Community ◽  
Gut Microbiome ◽  
Microbial Community Composition ◽  
Plant Secondary Metabolites ◽  
Free Access ◽  
Rrna Gene ◽  
Phascolarctos Cinereus ◽  
Gut Microbes ◽  
Principal Coordinates ◽  
Unweighted Unifrac

BackgroundThe diet of the koala (Phascolarctos cinereus) is comprised almost exclusively of foliage from the genusEucalyptus(family Myrtaceae).Eucalyptusproduces a wide variety of potentially toxic plant secondary metabolites which have evolved as chemical defences against herbivory. The koala is classified as an obligate dietary specialist, and although dietary specialisation is rare in mammalian herbivores, it has been found elsewhere to promote a highly-conserved but low-diversity gut microbiome. The gut microbes of dietary specialists have been found sometimes to enhance tolerance of dietary PSMs, facilitating competition-free access to food. Although the koala and its gut microbes have evolved together to utilise a low nutrient, potentially toxic diet, their gut microbiome has not previously been assessed in conjunction with diet quality. Thus, linking the two may provide new insights in to the ability of the koala to extract nutrients and detoxify their potentially toxic diet.MethodThe 16S rRNA gene was used to characterise the composition and diversity of faecal bacterial communities from a wild koala population (n = 32) comprising individuals that predominately eat either one of two different food species, one the strongly preferred and relatively nutritious speciesEucalyptus viminalis, the other comprising the less preferred and less digestible speciesEucalyptus obliqua.ResultsAlpha diversity indices indicated consistently and significantly lower diversity and richness in koalas eatingE. viminalis. Assessment of beta diversity using both weighted and unweighted UniFrac matrices indicated that diet was a strong driver of both microbial community structure, and of microbial presence/absence across the combined koala population and when assessed independently. Further, principal coordinates analysis based on both the weighted and unweighted UniFrac matrices for the combined and separated populations, also revealed a separation linked to diet. During our analysis of the OTU tables we also detected a strong association between microbial community composition and host diet. We found that the phyla Bacteroidetes and Firmicutes were co-dominant in all faecal microbiomes, with Cyanobacteria also co-dominant in some individuals; however, theE. viminalisdiet produced communities dominated by the generaParabacteroidesand/orBacteroides, whereas theE. obliqua-associated diets were dominated by unidentified genera from the family Ruminococcaceae.DiscussionWe show that diet differences, even those caused by differential consumption of the foliage of two species from the same plant genus, can profoundly affect the gut microbiome of a specialist folivorous mammal, even amongst individuals in the same population. We identify key microbiota associated with each diet type and predict functions within the microbial community based on 80 previously identifiedParabacteroidesand Ruminococcaceae genomes.

Selective Bacterial Community Enrichment Between the Pitcher Plants Sarracenia Minor and Sarracenia Flava

2020 ◽  
Author(s):  
Nikolas M. Stasulli ◽  
Scott M. Yourstone ◽  
Ilon Weinstein ◽  
Elizabeth Ademski ◽  
Elizabeth A. Shank
Keyword(s):  
Microbial Community ◽  
Bacterial Community ◽  
Prey Availability ◽  
Microbial Community Composition ◽  
Geographic Location ◽  
Rrna Gene ◽  
Natural Ecosystems ◽  
Community Members ◽  
Pitcher Plants ◽  
Naturally Occurring

Abstract BackgroundThe interconnected and overlapping habitats present in natural ecosystems remain a challenge in determining the forces driving microbial community composition. The cup-like leaf structures of some carnivorous plants, including the family Sarraceniaceae, are self-contained ecological habitats that represent systems for exploring such microbial ecology questions. We investigated whether Sarracenia minor and Sarracenia flava, when sampled at the same geographic location and time, cultivate unique microbiota; an indication of biotic selection of microbes due to eliminating many of the environmental variable present in other studies comparing samples harvested over several time points. ResultsDNA was extracted from the decomposing detritus trapped in the base of each Sarracenia leaf pitcher. We profiled a portion of the 16S rRNA gene across the bacterial community members present in this detritus using Illumina MiSeq technology. We identified a surprising amount of diversity within each pitcher, but also discovered that the two Sarracenia species each contained distinct, enriched microbial community members. This suggests a non-random establishment of microbial communities within these two Sarracenia species.ConclusionsOverall, our results indicate that microbial selection is occurring within the pitchers of these two closely related plant species, which is not due to factors such as geographic location, weather, or prey availability. This suggests that specific features of S. minor and S. flava may play a role in fostering specific insect-decomposing microbiomes. These naturally occurring microbial ecosystems can be developed to answer important questions about microbial community succession, disruption, and member contributions to the community. This study will help further establish carnivorous pitcher plants as a model system for studying confined, naturally occurring bacterial communities.

scholarly journals Antibiotic resistome and microbial community structure during anaerobic co-digestion of food waste, paper and cardboard

2020 ◽  
Vol 96 (2) ◽  
Author(s):  
Kärt Kanger ◽  
Nigel G H Guilford ◽  
HyunWoo Lee ◽  
Camilla L Nesbø ◽  
Jaak Truu ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Solid State ◽  
Food Waste ◽  
Microbial Community Structure ◽  
Microbial Community Composition ◽  
Microbial Community Analysis ◽  
Waste Paper ◽  
Rrna Gene ◽  
Significant Shift

ABSTRACT Solid organic waste is a significant source of antibiotic resistance genes (ARGs) and effective treatment strategies are urgently required to limit the spread of antimicrobial resistance. Here, we studied ARG diversity and abundance as well as the relationship between antibiotic resistome and microbial community structure within a lab-scale solid-state anaerobic digester treating a mixture of food waste, paper and cardboard. A total of 10 samples from digester feed and digestion products were collected for microbial community analysis including small subunit rRNA gene sequencing, total community metagenome sequencing and high-throughput quantitative PCR. We observed a significant shift in microbial community composition and a reduction in ARG diversity and abundance after 6 weeks of digestion. ARGs were identified in all samples with multidrug resistance being the most abundant ARG type. Thirty-two per cent of ARGs detected in digester feed were located on plasmids indicating potential for horizontal gene transfer. Using metagenomic assembly and binning, we detected potential bacterial hosts of ARGs in digester feed, which included Erwinia, Bifidobacteriaceae, Lactococcus lactis and Lactobacillus. Our results indicate that the process of sequential solid-state anaerobic digestion of food waste, paper and cardboard tested herein provides a significant reduction in the relative abundance of ARGs per 16S rRNA gene.

scholarly journals Changes in the Active, Dead, and Dormant Microbial Community Structure across a Pleistocene Permafrost Chronosequence

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Alexander Burkert ◽  
Thomas A. Douglas ◽  
Mark P. Waldrop ◽  
Rachel Mackelprang
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Communities ◽  
Community Composition ◽  
Environmental Conditions ◽  
Microbial Community Composition ◽  
Rrna Gene ◽  
Subzero Temperatures ◽  
Dormant Cells

ABSTRACTPermafrost hosts a community of microorganisms that survive and reproduce for millennia despite extreme environmental conditions, such as water stress, subzero temperatures, high salinity, and low nutrient availability. Many studies focused on permafrost microbial community composition use DNA-based methods, such as metagenomics and 16S rRNA gene sequencing. However, these methods do not distinguish among active, dead, and dormant cells. This is of particular concern in ancient permafrost, where constant subzero temperatures preserve DNA from dead organisms and dormancy may be a common survival strategy. To circumvent this, we applied (i) LIVE/DEAD differential staining coupled with microscopy, (ii) endospore enrichment, and (iii) selective depletion of DNA from dead cells to permafrost microbial communities across a Pleistocene permafrost chronosequence (19,000, 27,000, and 33,000 years old). Cell counts and analysis of 16S rRNA gene amplicons from live, dead, and dormant cells revealed how communities differ between these pools, how they are influenced by soil physicochemical properties, and whether they change over geologic time. We found evidence that cells capable of forming endospores are not necessarily dormant and that members of the classBacilliwere more likely to form endospores in response to long-term stressors associated with permafrost environmental conditions than members of theClostridia, which were more likely to persist as vegetative cells in our older samples. We also found that removing exogenous “relic” DNA preserved within permafrost did not significantly alter microbial community composition. These results link the live, dead, and dormant microbial communities to physicochemical characteristics and provide insights into the survival of microbial communities in ancient permafrost.IMPORTANCEPermafrost soils store more than half of Earth’s soil carbon despite covering ∼15% of the land area (C. Tarnocai et al., Global Biogeochem Cycles 23:GB2023, 2009, https://doi.org/10.1029/2008GB003327). This permafrost carbon is rapidly degraded following a thaw (E. A. G. Schuur et al., Nature 520:171–179, 2015, https://doi.org/10.1038/nature14338). Understanding microbial communities in permafrost will contribute to the knowledge base necessary to understand the rates and forms of permafrost C and N cycling postthaw. Permafrost is also an analog for frozen extraterrestrial environments, and evidence of viable organisms in ancient permafrost is of interest to those searching for potential life on distant worlds. If we can identify strategies microbial communities utilize to survive in permafrost, it may yield insights into how life (if it exists) survives in frozen environments outside of Earth. Our work is significant because it contributes to an understanding of how microbial life adapts and survives in the extreme environmental conditions in permafrost terrains.

scholarly journals pH and Phosphate Induced Shifts in Carbon Flow and Microbial Community during Thermophilic Anaerobic Digestion

2020 ◽  
Vol 8 (2) ◽  
pp. 286
Author(s):  
Nina Lackner ◽  
Andreas O. Wagner ◽  
Rudolf Markt ◽  
Paul Illmer
Keyword(s):  
Microbial Community ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
Carbon Flow ◽  
Rrna Gene ◽  
Organic Substrates ◽  
Ch4 Production ◽  
Ph Conditions ◽  
Ph Range ◽  
In The Beginning

pH is a central environmental factor influencing CH4 production from organic substrates, as every member of the complex microbial community has specific pH requirements. Here, we show how varying pH conditions (5.0–8.5, phosphate buffered) and the application of a phosphate buffer per se induce shifts in the microbial community composition and the carbon flow during nine weeks of thermophilic batch digestion. Beside monitoring the methane production as well as volatile fatty acid concentrations, amplicon sequencing of the 16S rRNA gene was conducted. The presence of 100 mM phosphate resulted in reduced CH4 production during the initial phase of the incubation, which was characterized by a shift in the dominant methanogenic genera from a mixed Methanosarcina and Methanoculleus to a pure Methanoculleus system. In buffered samples, acetate strongly accumulated in the beginning of the batch digestion and subsequently served as a substrate for methanogens. Methanogenesis was permanently inhibited at pH values ≤5.5, with the maximum CH4 production occurring at pH 7.5. Adaptations of the microbial community to the pH variations included shifts in the archaeal and bacterial composition, as less competitive organisms with a broad pH range were able to occupy metabolic niches at unfavorable pH conditions.

scholarly journals Physicochemical Parameters Affecting the Distribution and Diversity of the Water Column Microbial Community in the High-Altitude Andean Lake System of La Brava and La Punta

2020 ◽  
Vol 8 (8) ◽  
pp. 1181
Author(s):  
Reynaldo Núñez Salazar ◽  
Carlos Aguirre ◽  
Jorge Soto ◽  
Pamela Salinas ◽  
Carlos Salinas ◽  
...  
Keyword(s):  
Microbial Community ◽  
High Altitude ◽  
Water Column ◽  
Physicochemical Parameters ◽  
Microbial Community Composition ◽  
Atacama Desert ◽  
Rrna Gene ◽  
16S Rrna Gene Analysis ◽  
Lake System ◽  
Influence Of Water

Due to the low incidence of precipitation attributed to climate change, many high-altitude Andean lakes (HAALs) and lagoons distributed along the central Andes in South America may soon disappear. This includes La Brava–La Punta, a brackish lake system located south of the Salar de Atacama within a hyper-arid and halophytic biome in the Atacama Desert. Variations in the physicochemical parameters of the water column can induce changes in microbial community composition, which we aimed to determine. Sixteen sampling points across La Brava–La Punta were studied to assess the influence of water physicochemical properties on the aquatic microbial community, determined via 16S rRNA gene analysis. Parameters such as pH and the concentrations of silica, magnesium, calcium, salinity, and dissolved oxygen showed a more homogenous pattern in La Punta samples, whereas those from La Brava had greater variability; pH and total silica were significantly different between La Brava and La Punta. The predominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia. The genera Psychroflexus (36.85%), Thiomicrospira (12.48%), and Pseudomonas (7.81%) were more abundant in La Brava, while Pseudospirillum (20.73%) and Roseovarius (17.20%) were more abundant in La Punta. Among the parameters, pH was the only statistically significant factor influencing the diversity within La Brava lake. These results complement the known microbial diversity and composition in the HAALs of the Atacama Desert.

scholarly journals Soil Microbial Community Assembly and Interactions Are Constrained by Nitrogen and Phosphorus in Broadleaf Forests of Southern China

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 285 ◽  
Author(s):  
Mengxin Zhao ◽  
Jing Cong ◽  
Jingmin Cheng ◽  
Qi Qi ◽  
Yuyu Sheng ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Community Assembly ◽  
Soil Microbial Community ◽  
Southern China ◽  
Microbial Community Composition ◽  
Nitrogen And Phosphorus ◽  
Soil Microbial ◽  
Microbial Community Assembly ◽  
Microbial Functional Gene

Subtropical and tropical broadleaf forests play important roles in conserving biodiversity and regulating global carbon cycle. Nonetheless, knowledge about soil microbial diversity, community composition, turnover and microbial functional structure in sub- and tropical broadleaf forests is scarce. In this study, high-throughput sequencing was used to profile soil microbial community composition, and a micro-array GeoChip 5.0 was used to profile microbial functional gene distribution in four sub- and tropical broadleaf forests (HS, MES, HP and JFL) in southern China. The results showed that soil microbial community compositions differed dramatically among all of four forests. Soil microbial diversities in JFL were the lowest (5.81–5.99) and significantly different from those in the other three forests (6.22–6.39). Furthermore, microbial functional gene interactions were the most complex and closest, likely in reflection to stress associated with the lowest nitrogen and phosphorus contents in JFL. In support of the importance of environmental selection, we found selection (78–96%) dominated microbial community assembly, which was verified by partial Mantel tests showing significant correlations between soil phosphorus and nitrogen content and microbial community composition. Taken together, these results indicate that nitrogen and phosphorus are pivotal in shaping soil microbial communities in sub- and tropical broadleaf forests in southern China. Changes in soil nitrogen and phosphorus, in response to plant growth and decomposition, will therefore have significant changes in both microbial community assembly and interaction.

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