Quorum Sensing Regulates the Hydrolytic Enzyme Production and Community Composition of Heterotrophic Bacteria in Coastal Waters

Heterotrophic microbial communities play a central role in biogeochemical cycles in the ocean by degrading organic matter through the synthesis of extracellular hydrolytic enzymes. Their hydrolysis rates result from the community’s genomic potential and the differential expression of this genomic potential. Cell-cell communication pathways such as quorum sensing (QS) could impact both aspects and, consequently, structure marine ecosystem functioning. However, the role of QS communications in complex natural assemblages remains largely unknown. In this study, we investigated whether N-acylhomoserine lactones (AHLs), a type of QS signal, could regulate both hydrolytic activities and the bacterial community composition (BCC) of marine planktonic assemblages. To this extent, we carried out two microcosm experiments, adding five different AHLs to bacterial communities sampled in coastal waters (during early and peak bloom) and monitoring their impact on enzymatic activities and diversity over 48 h. Several specific enzymatic activities were impacted during both experiments, as early as 6 h after the AHL amendments. The BCC was also significantly impacted by the treatments after 48 h, and correlated with the expression of the hydrolytic activities, suggesting that changes in hydrolytic intensities may drive changes in BCC. Overall, our results suggest that QS communication could participate in structuring both the function and diversity of marine bacterial communities.

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Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Genes ◽

10.3390/genes12060855 ◽

2021 ◽

Vol 12 (6) ◽

pp. 855

Author(s):

Mikołaj Kokociński ◽

Dariusz Dziga ◽

Adam Antosiak ◽

Janne Soininen

Keyword(s):

Environmental Factors ◽

Community Composition ◽

Phytoplankton Community ◽

Heterotrophic Bacteria ◽

Bacterial Community Composition ◽

Physical Factors ◽

Research Attention ◽

Phytoplankton Community Composition ◽

The Impact ◽

Bacteria Communities

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.

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Rhizobacterial communities of five co-occurring desert halophytes

PeerJ ◽

10.7717/peerj.5508 ◽

2018 ◽

Vol 6 ◽

pp. e5508 ◽

Cited By ~ 3

Author(s):

Yan Li ◽

Yan Kong ◽

Dexiong Teng ◽

Xueni Zhang ◽

Xuemin He ◽

...

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Plant Species ◽

Bacterial Communities ◽

Bacterial Community Composition ◽

Community Diversity ◽

Species Identity ◽

Halostachys Caspica ◽

Lycium Ruthenicum ◽

Limonium Gmelinii

BackgroundRecently, researches have begun to investigate the microbial communities associated with halophytes. Both rhizobacterial community composition and the environmental drivers of community assembly have been addressed. However, few studies have explored the structure of rhizobacterial communities associated with halophytic plants that are co-occurring in arid, salinized areas.MethodsFive halophytes were selected for study: these co-occurred in saline soils in the Ebinur Lake Nature Reserve, located at the western margin of the Gurbantunggut Desert of Northwestern China. Halophyte-associated bacterial communities were sampled, and the bacterial 16S rDNA V3–V4 region amplified and sequenced using the Illumina Miseq platform. The bacterial community diversity and structure were compared between the rhizosphere and bulk soils, as well as among the rhizosphere samples. The effects of plant species identity and soil properties on the bacterial communities were also analyzed.ResultsSignificant differences were observed between the rhizosphere and bulk soil bacterial communities. Diversity was higher in the rhizosphere than in the bulk soils. Abundant taxonomic groups (from phylum to genus) in the rhizosphere were much more diverse than in bulk soils. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Planctomycetes were the most abundant phyla in the rhizosphere, while Proteobacteria and Firmicutes were common in bulk soils. Overall, the bacterial community composition were not significantly differentiated between the bulk soils of the five plants, but community diversity and structure differed significantly in the rhizosphere. The diversity ofHalostachys caspica,Halocnemum strobilaceumandKalidium foliatumassociated bacterial communities was lower than that ofLimonium gmeliniiandLycium ruthenicumcommunities. Furthermore, the composition of the bacterial communities ofHalostachys caspicaandHalocnemum strobilaceumwas very different from those ofLimonium gmeliniiandLycium ruthenicum. The diversity and community structure were influenced by soil EC, pH and nutrient content (TOC, SOM, TON and AP); of these, the effects of EC on bacterial community composition were less important than those of soil nutrients.DiscussionHalophytic plant species played an important role in shaping associated rhizosphere bacterial communities. When salinity levels were constant, soil nutrients emerged as key factors structuring bacterial communities, while EC played only a minor role. Pairwise differences among the rhizobacterial communities associated with different plant species were not significant, despite some evidence of differentiation. Further studies involving more halophyte species, and individuals per species, are necessary to elucidate plant species identity effects on the rhizosphere for co-occurring halophytes.

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Significant Differences in the Gut Bacterial Communities of Hooded Crane (Grus monacha) in Different Seasons at a Stopover Site on the Flyway

Animals ◽

10.3390/ani10040701 ◽

2020 ◽

Vol 10 (4) ◽

pp. 701 ◽

Cited By ~ 1

Author(s):

Fengling Zhang ◽

Xingjia Xiang ◽

Yuanqiu Dong ◽

Shaofei Yan ◽

Yunwei Song ◽

...

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Community Composition ◽

Bacterial Communities ◽

Bacterial Community Structure ◽

Bacterial Community Composition ◽

Stopover Site ◽

Intestinal Bacterial Community ◽

Hooded Crane ◽

Grus Monacha

Intestinal bacterial communities form an integral component of the organism. Many factors influence gut bacterial community composition and diversity, including diet, environment and seasonality. During seasonal migration, birds use many habitats and food resources, which may influence their intestinal bacterial community structure. Hooded crane (Grus monacha) is a migrant waterbird that traverses long distances and occupies varied habitats. In this study, we investigated the diversity and differences in intestinal bacterial communities of hooded cranes over the migratory seasons. Fecal samples from hooded cranes were collected at a stopover site in two seasons (spring and fall) in Lindian, China, and at a wintering ground in Shengjin Lake, China. We analyzed bacterial communities from the fecal samples using high throughput sequencing (Illumina Mi-seq). Firmicutes, Proteobacteria, Tenericutes, Cyanobacteria, and Actinobacteria were the dominant phyla across all samples. The intestinal bacterial alpha-diversity of hooded cranes in winter was significantly higher than in fall and spring. The bacterial community composition significantly differed across the three seasons (ANOSIM, P = 0.001), suggesting that seasonal fluctuations may regulate the gut bacterial community composition of migratory birds. This study provides baseline information on the seasonal dynamics of intestinal bacterial community structure in migratory hooded cranes.

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Multiple Stressors Determine Community Structure and Estimated Function of River Biofilm Bacteria

Applied and Environmental Microbiology ◽

10.1128/aem.00291-20 ◽

2020 ◽

Vol 86 (12) ◽

Cited By ~ 1

Author(s):

Ferran Romero ◽

Vicenç Acuña ◽

Sergi Sabater

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Communities ◽

Pesticide Exposure ◽

Multiple Stressors ◽

Bacterial Community Composition ◽

Freshwater Ecosystems ◽

Low Flow ◽

Hydrological Stress ◽

The Individual

ABSTRACT Freshwater ecosystems are exposed to multiple stressors, but their individual and combined effects remain largely unexplored. Here, we investigated the response of stream biofilm bacterial communities to warming, hydrological stress, and pesticide exposure. We used 24 artificial streams on which epilithic (growing on coarse sediments) and epipsammic (growing on fine sediments) stream biofilms were maintained. Bacterial community composition and estimated function of biofilms exposed during 30 days to individual and combined stressors were assessed using 16S rRNA gene metabarcoding. Among the individual effects by stressors, hydrological stress (i.e., a simulated low-flow situation) was the most relevant, since it significantly altered 57% of the most abundant bacterial taxa (n = 28), followed by warming (21%) and pesticide exposure (11%). Regarding the combined effects, 16% of all stressor combinations resulted in significant interactions on bacterial community composition and estimated function. Antagonistic responses prevailed (57 to 89% of all significant interactions), followed by synergisms (11 to 43%), on specific bacterial taxa, indicating that multiple-stressor scenarios could lead to unexpected shifts in the community composition and associated functions of riverine bacterial communities. IMPORTANCE Freshwater ecosystems such as rivers are of crucial importance for human well-being. However, human activities result in many stressors (e.g., toxic chemicals, increased water temperatures, and hydrological alterations) cooccurring in rivers and streams worldwide. Among the many organisms inhabiting rivers and streams, bacteria are ecologically crucial; they are placed at the base of virtually all food webs and they recycle the organic matter needed for bigger organisms. Most of these bacteria are in close contact with river substratum, where they form the biofilms. There is an urgent need to evaluate the effects of these stressors on river biofilms, so we can anticipate future environmental problems. In this study, we experimentally exposed river biofilms to a pesticide mixture, an increase in water temperature and a simulated low-flow condition, in order to evaluate the individual and joint effects of these stressors on the bacterial community composition and estimated function.

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Variation of bacterial communities in Muztagh ice core from 1869 to 2000

10.5194/egusphere-egu2020-6328 ◽

2020 ◽

Author(s):

Yongqin Liu ◽

Tandong Yao ◽

Baiqing Xu

Keyword(s):

Bacterial Community ◽

Temporal Variation ◽

Community Composition ◽

Bacterial Communities ◽

Environmental Variables ◽

Climate Changes ◽

Bacterial Community Composition ◽

Ice Core ◽

The Past ◽

Stage 1

Many studies focusing on the physical and chemical indicators of the ice core reflected the climate changes. However, only few biological indicators indicated the past climate changes which are mainly focused in biomass rather than diversity. How the biodiversity response to the climate change during the past hundred years is still unknow. Glaciers in Mt. Muztagh Ata region are in&#64258;uenced by the year-round westerly circulation. We firstly disclosed annual variations of bacterial community compositions in ice core over the past 130 years from Muztagh Glacier, the western Tibetan Plateau. Temporal variation in bacterial abundance was strongly controlled by DOC, TN, &#948;18O, Ca2+, SO42&#8722;, NH4+ and NO3&#8722;. Proteobacteria, Actinobacteria and Firmicutes were the three most abundant bacterial phyla, accounting for 49.3%, 21.3% and 11.0% of the total community, respectively. The abundances of Firmicutes and Bacteroidetes pronouncedly increased over time throughout the entire ice core. UPGMA cluster analysis of the bacterial community composition separated the all ice core samples into two main clusters along the temporal variation. The first cluster consisted of samples from 1951 to 2000 and the second cluster contained main samples during the period of 1869-1950. The stage 1 and stage 2 bacterial community dissimilarities increased linearly with time on the basis of the Bray-Curtis distance, indicating a similar temporal&#8211;decay relationship between the stage 1 and stage 2 bacterial communities. Of all the environmental variables examined, only DOC and NH4+ exhibited very strong negative correlations with bacterial Chao1-richness. 18O was another important variable in shaping the ice core bacterial community composition and contributed 1.6% of the total variation. Moreover, DistLM analysis indicated that the environmental variables explained more variation in the stage 1 community (20.1%) than that of the stage 2 community (19.9%).

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Small tropical islands with dense human population: Differences in water quality of near-shore waters are associated with distinct bacterial communities

10.7287/peerj.preprints.26553v1 ◽

2018 ◽

Author(s):

Hauke Kegler ◽

Christiane Hassenrueck ◽

Pia Kegler ◽

Tim C Jennerjahn ◽

Muhammad Lukman ◽

...

Keyword(s):

Water Quality ◽

Organic Matter ◽

Coral Reef ◽

Bacterial Community ◽

Water Column ◽

Community Composition ◽

Bacterial Communities ◽

Bacterial Community Composition ◽

Back Reef ◽

Anthropogenic Inputs

Water quality deterioration caused by an enrichment in inorganic and organic matter due to anthropogenic inputs is one of the major local threats to coral reefs in Indonesia. However, even though bacteria are important mediators in coral reef ecosystems, little is known about the response of individual taxa and whole bacterial communities to these anthropogenic inputs. The present study is the first to investigate how bacterial community composition responds to small-scale changes in water quality in several coral reef habitats of the Spermonde Archipelago including the water column, particles and back reef sediments, on a densely populated and an uninhabited island. The main aims were to elucidate if a) water quality indicators and organic matter concentrations differ between the uninhabited and the densely populated island of the archipelago, and b) if there are differences in bacterial community composition in back-reef sediments and in the water column, which are associated with differences in water quality. Several key water quality parameters, such as inorganic nitrate and phosphate, chlorophyll a, and transparent exopolymer particles (TEP) were significantly higher at the inhabited than at the uninhabited island. Bacterial communities in sediments and particle attached communities were significantly different between the two islands with bacterial taxa commonly associated with nutrient and organic matter rich conditions occurring in higher proportions at the inhabited island. Within the individual reef habitats, variations in bacterial community composition between the islands are associated with differences in water quality. We also observed that copiotrophic, opportunistic bacterial taxa were enriched at the inhabited island with its higher chlorophyll a, dissolved organic carbon (DOC) and TEP concentrations. Given the increasing strain on tropical coastal ecosystems, this study suggests that effluents from densely populated islands lacking sewage treatment can alter bacterial communities that may be important for coral reef ecosystem function.

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Local domestication of microbes via cassava beer fermentation

10.7287/peerj.preprints.233 ◽

2014 ◽

Author(s):

Alese Colehour ◽

James F Meadow ◽

Tara J Cepon-Robins ◽

Theresa E Gildner ◽

Melissa A Liebert ◽

...

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Communities ◽

Manihot Esculenta ◽

Nutritional Quality ◽

High Throughput Sequencing ◽

Bacterial Community Composition ◽

Ribosomal Gene ◽

Ecuadorian Amazon ◽

Traditional Fermentation

Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) improves nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes beneficial to human health, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples, demonstrating that chicha is a source of organisms related to known probiotics. Significantly greater taxonomic similarity was observed between communities in chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human preference, may be responsible for creating locally adapted and regionally resilient ferments. Our results suggest that traditional fermentation may be a form of domestication that provides endemic beneficial inocula for consumers.

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Small tropical islands with dense human population: differences in water quality of near-shore waters are associated with distinct bacterial communities

PeerJ ◽

10.7717/peerj.4555 ◽

2018 ◽

Vol 6 ◽

pp. e4555 ◽

Cited By ~ 3

Author(s):

Hauke F. Kegler ◽

Christiane Hassenrück ◽

Pia Kegler ◽

Tim C. Jennerjahn ◽

Muhammad Lukman ◽

...

Keyword(s):

Water Quality ◽

Organic Matter ◽

Coral Reef ◽

Bacterial Community ◽

Water Column ◽

Community Composition ◽

Bacterial Communities ◽

Bacterial Community Composition ◽

Back Reef ◽

Anthropogenic Inputs

Water quality deterioration caused by an enrichment in inorganic and organic matter due to anthropogenic inputs is one of the major local threats to coral reefs in Indonesia. However, even though bacteria are important mediators in coral reef ecosystems, little is known about the response of individual taxa and whole bacterial communities to these anthropogenic inputs. The present study is the first to investigate how bacterial community composition responds to small-scale changes in water quality in several coral reef habitats of the Spermonde Archipelago including the water column, particles, and back-reef sediments, on a densely populated and an uninhabited island. The main aims were to elucidate if (a) water quality indicators and organic matter concentrations differ between the uninhabited and the densely populated island of the archipelago, and (b) if there are differences in bacterial community composition in back-reef sediments and in the water column, which are associated with differences in water quality. Several key water quality parameters, such as inorganic nitrate and phosphate, chlorophylla, and transparent exopolymer particles (TEP) were significantly higher at the inhabited than at the uninhabited island. Bacterial communities in sediments and particle-attached communities were significantly different between the two islands with bacterial taxa commonly associated with nutrient and organic matter-rich conditions occurring in higher proportions at the inhabited island. Within the individual reef habitats, variations in bacterial community composition between the islands were associated with differences in water quality. We also observed that copiotrophic, opportunistic bacterial taxa were enriched at the inhabited island with its higher chlorophylla, dissolved organic carbon and TEP concentrations. Given the increasing strain on tropical coastal ecosystems, this study suggests that effluents from densely populated islands lacking sewage treatment can alter bacterial communities that may be important for coral reef ecosystem function.

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Resistance and Not Plant Fruit Traits Determine Root-Associated Bacterial Community Composition along a Domestication Gradient in Tomato

Plants ◽

10.3390/plants11010043 ◽

2021 ◽

Vol 11 (1) ◽

pp. 43

Author(s):

Lisanne Smulders ◽

Victoria Ferrero ◽

Eduardo de la Peña ◽

María J. Pozo ◽

Juan Antonio Díaz Pendón ◽

...

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Plant Resistance ◽

Bacterial Communities ◽

Species Interactions ◽

Plant Traits ◽

Bacterial Community Composition ◽

Agricultural Practices ◽

Fruit Traits ◽

Resistance Traits

Soil bacterial communities are involved in multiple ecosystem services, key in determining plant productivity. Crop domestication and intensive agricultural practices often disrupt species interactions with unknown consequences for rhizosphere microbiomes. This study evaluates whether variation in plant traits along a domestication gradient determines the composition of root-associated bacterial communities; and whether these changes are related to targeted plant traits (e.g., fruit traits) or are side effects of less-often-targeted traits (e.g., resistance) during crop breeding. For this purpose, 18 tomato varieties (wild and modern species) differing in fruit and resistance traits were grown in a field experiment, and their root-associated bacterial communities were characterised. Root-associated bacterial community composition was influenced by plant resistance traits and genotype relatedness. When only considering domesticated tomatoes, the effect of resistance on bacterial OTU composition increases, while the effect due to phylogenetic relatedness decreases. Furthermore, bacterial diversity positively correlated with plant resistance traits. These results suggest that resistance traits not selected during domestication are related to the capacity of tomato varieties to associate with different bacterial groups. Taken together, these results evidence the relationship between plant traits and bacterial communities, pointing out the potential of breeding to affect plant microbiomes.

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Metagenomics reveals diet-specific specialization of bacterial communities in fungus gardens of grass- and dicot-cutter ants

10.1101/250993 ◽

2018 ◽

Cited By ~ 1

Author(s):

Lily Khadempour ◽

Huan Fan ◽

Ken Keefover-Ring ◽

Camila Carlos ◽

Nilson S. Nagamoto ◽

...

Keyword(s):

Bacterial Community ◽

Community Composition ◽

Bacterial Communities ◽

Potential Role ◽

Sequence Data ◽

Bacterial Community Composition ◽

Fungus Garden ◽

Functional Profiles ◽

Ant Fungus

AbstractLeaf-cutter ants in the genusAttaare dominant herbivores in the Neotropics. While most species ofAttacut dicots to incorporate into their fungus gardens, some species specialize on grasses. Here we examine the bacterial community associated with the fungus gardens of grass- and dicot-cutter ants to examine how changes in substrate input affect the bacterial community. We sequenced the metagenomes of 12Attafungus gardens, across four species of ants, with a total of 5.316 Gbp of sequence data. We show significant differences in the fungus garden bacterial community composition between dicot- and grass-cutter ants, with grass-cutter ants having lower diversity. Reflecting this difference in community composition, the bacterial functional profiles between the fungus gardens are significantly different. Specifically, grass-cutter ant fungus garden metagenomes are particularly enriched for genes responsible for amino acid, siderophore, and terpenoid biosynthesis while dicot-cutter ant fungus gardens metagenomes are enriched in genes involved in membrane transport. These differences in bacterial community composition and functional capacity show that different substrate inputs matter for fungus garden bacteria, and sheds light on the potential role of bacteria in mediating the ants’ transition to the use of a novel substrate.

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