scholarly journals Analysis of nifH DNA and RNA reveals a disproportionate contribution to nitrogenase activities by rare plankton-associated diazotrophs

2019 ◽  
Author(s):  
Qingsong Yang ◽  
Junde Dong ◽  
Manzoor Ahmad ◽  
Juan Ling ◽  
Weiguo Zhou ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Changes ◽  
Northern South China Sea ◽  
Nifh Gene ◽  
Biological Response ◽  
Alpha Diversity ◽  
Equal Proportion ◽  
Dna And Rna ◽  
Abundant Otus ◽  
Nitrogenase Activities

Abstract Holobionts comprising nitrogen-fixing diazotrophs and phytoplankton or zooplankton are ubiquitous in the pelagic sea. However, neither the community structure of plankton-associated diazotrophs (PADs) nor their nitrogenase transcriptional activity are well-understood. In this study, we used nifH gene Illumina sequencing and quantitative PCR to characterize the total and active community structure of PADs in the euphotic zone of the northern South China Sea. The results of DNA- and RNA-derived nifH gene revealed a higher alpha-diversity in the active than in the total community. Moreover, the compositional resemblance among different sites was less for active than for total communities of PADs. Eight of the 20 abundant OTUs were phylogenetically affiliated with Trichodesmium and occurred in approximately equal proportion in both the DNA and RNA libraries. The analysis of nifH gene expression level showed uneven attribute of the abundance and nitrogenase activities by the remaining 12 OTUs. Taxa belonging to cluster III and Betaproteobacteria were present at moderate abundance but exhibited negligible nitrogenase transcription activity. Whereas, the abundances of Richelia, Deltaproteobacteria and Gammaproteobacteria were low but the contribution of these groups to nitrogenase transcription was disproportionately high. The substantial variation in community structure among active dizatrophic fractions compared to the total communities suggests that the former are better indicators of biological response to environmental changes. Altogether, our study highlights the importance of rare PADs groups in nitrogen fixation in plankton holobionts, evidenced by their high level of nitrogenase transcription.

scholarly journals Analysis of nifH DNA and RNA reveals a disproportionate contribution to nitrogenase activities by rare plankton-associated diazotrophs

2019 ◽  
Author(s):  
Qingsong Yang ◽  
Junde Dong ◽  
Manzoor Ahmad ◽  
Juan Ling ◽  
Weiguo Zhou ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Changes ◽  
Northern South China Sea ◽  
Nifh Gene ◽  
Size Fraction ◽  
Alpha Diversity ◽  
Equal Proportion ◽  
Dna And Rna ◽  
Abundant Otus ◽  
Nitrogenase Activities

Abstract Abstract Background: Holobionts comprising nitrogen-fixing diazotrophs and phytoplankton or zooplankton are ubiquitous in the pelagic sea. However, neither the community structure of plankton-associated diazotrophs (PADs) nor their nitrogenase transcriptional activity are well-understood. In this study, we used nifH gene Illumina sequencing and quantitative PCR to characterize the community composition and nifH expression profile of PADs with > 100 µm size fraction in the euphotic zone of the northern South China Sea. Results: The results of DNA- and RNA-derived nifH gene revealed a higher alpha-diversity in the active than in the total community. Moreover, the compositional resemblance among different sites was less for active than for total communities of PADs. We characterized the 20 most abundant OTUs by ranking the sum of sequence reads across 9 sampling stations for individual OTUs in both nifH DNA and RNA libraries, and then assessed their phylogenetic relatedness. Eight of the 20 abundant OTUs were phylogenetically affiliated with Trichodesmium and occurred in approximately equal proportion in both the DNA and RNA libraries. The analysis of nifH gene expression level showed uneven attribute of the abundance and nitrogenase activities by the remaining 12 OTUs. Taxa belonging to cluster III and Betaproteobacteria were present at moderate abundance but exhibited negligible nitrogenase transcription activity. Whereas, the abundances of Richelia, Deltaproteobacteria and Gammaproteobacteria were low but the contribution of these groups to nitrogenase transcription was disproportionately high. Conclusions: The substantial variation in community structure among active dizatrophic fractions compared to the total communities suggests that the former are better indicators of biological response to environmental changes. Altogether, our study highlights the importance of rare PADs groups in nitrogen fixation in plankton holobionts, evidenced by their high level of nitrogenase transcription.

scholarly journals Changes in Heterotrophic Picoplankton Community Structure after Induction of a Phytoplankton Bloom under Different Light Regimes

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 195 ◽  
Author(s):  
Karayanni ◽  
Kormas ◽  
Moustaka-Gouni ◽  
Sommer
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Relative Abundance ◽  
Environmental Changes ◽  
Phytoplankton Bloom ◽  
Phytoplankton Growth ◽  
Light Regimes ◽  
Operational Taxonomic Units ◽  
Abundant Otus

Bacterial and archaeal diversity and succession were studied during a mesocosm experiment that investigated whether changing light regimes could affect the onset of phytoplankton blooms. For this, 454-pyrosequencing of the bacterial V1-V3 and archaeal V3-V9 16S rRNA regions was performed in samples collected from four mesocosms receiving different light irradiances at the beginning and the end of the experiment and during phytoplankton growth. In total, 46 bacterial operational taxonomic units (OTUs) with ≥1% relative abundance occurred (22–34 OTUs per mesocosm). OTUs were affiliated mainly with Rhodobacteraceae, Flavobacteriaceae and Alteromonadaceae. The four mesocosms shared 11 abundant OTUs. Dominance increased at the beginning of phytoplankton growth in all treatments and decreased thereafter. Maximum dominance was found in the mesocosms with high irradiances. Overall, specific bacterial OTUs had different responses in terms of relative abundance under in situ and high light intensities, and an early phytoplankton bloom resulted in different bacterial community structures both at high (family) and low (OTU) taxonomic levels. Thus, bacterial community structure and succession are affected by light regime, both directly and indirectly, which may have implications for an ecosystem’s response to environmental changes.

scholarly journals Diversity, Composition, and Activities of Nano- and Pico-Eukaryotes in the Northern South China Sea With Influences of Kuroshio Intrusion

2021 ◽  
Vol 8 ◽  
Author(s):  
Feipeng Wang ◽  
Bangqin Huang ◽  
Yuyuan Xie ◽  
Shujie Cai ◽  
Xiuxiu Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Dispersal Limitation ◽  
Kuroshio Intrusion ◽  
China Sea ◽  
Dna And Rna ◽  
Metabolic Activities ◽  
The Kuroshio

Nano- and pico-eukaryotes play important roles in the diversity and functions of marine ecosystems. Warm, saline, and nutrient-depleted water that originates in the Kuroshio Current seasonally intrudes into the northern South China Sea (NSCS) from autumn to spring. To clarify the mechanisms in shaping the community structure of nano- and pico-eukaryotes as well as impacts of the Kuroshio intrusion on the NSCS ecosystem, genomic DNA and RNA were co-extracted from samples collected at two depths from nine stations, and then the V9 region of 18S rDNA and rRNA was sequenced with high-throughput sequencing. Our results showed that Dinophyceae was the most diverse and abundant nanoeukaryotic group during the study period revealed by both DNA and RNA surveys. In contrast, the relative read abundance of MAST, Pelagophyceae, and Dinophyceae in the size fraction of picoeukaryotes might be largely underestimated by the DNA survey. The RNA survey was the more reliable method to investigate the eukaryotic community structure. Environmental filtering played an important role in shaping the community structure, and the sampling depth became the governing factor of the beta diversity under the environmental setting of stratification during the study period. The spatial variations in the diversity of nanoeukaryotes were subject to the dispersal limitation under the size rule. The effects of the Kuroshio intrusion on the nanoeukaryotic community structure might also be explained by the dispersal limitation. Overall, neutral processes are critical in shaping the community structure of nanoeukaryotes. The relative metabolic activities of nanoeukaryotes were relatively stable in accordance with the high similarity of community structure between sampling sites. The responses of the relative metabolic activities of picoeukaryotes to environmental factors displayed two distinct patterns: positive correlations with salinity and nutrients and negative with temperature for Dinophyceae, MAST, and Pelagophyceae, while reversed patterns for Mamiellophyceae and Radiolaria. Our findings improve the understanding of the nano- and pico-eukaryotic communities in the NSCS and the mechanisms of their assembly.

scholarly journals Incorporating genomic information and predicting gene expression patterns in a simplified biogeochemical model

2013 ◽  
Vol 10 (1) ◽  
pp. 815-850
Author(s):  
P. Wang ◽  
A. B. Burd ◽  
M. A. Moran ◽  
R. R. Hood ◽  
V. J. Coles ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Changes ◽  
Expression Patterns ◽  
Biological Response ◽  
Gene Clusters ◽  
Biogeochemical Model ◽  
Nitrogen And Phosphorus ◽  
Concentration Changes ◽  
Continuously Stirred Tank Reactor ◽  
And Function

Abstract. We present results from a new marine plankton model that combines selective biogeochemical processes with genetic information. The model allows for phytoplankton to adapt to a changing environment by invoking different utilization pathways for acquisition of nutrients (nitrogen and phosphorus) in response to concentration changes. The simulations use simplified environmental conditions represented by a continuously stirred tank reactor, which is populated by 96 different types of phytoplankton that differ in their physiological characteristics and nutrient uptake/metabolism genes. The results show that the simulated phytoplankton community structure is conceptually consistent with observed regional and global phytoplankton biogeography, the genome content from the dominant types of phytoplankton reflects the imposed environmental constraints, and the transcription of the gene clusters is qualitatively simulated according to the environmental changes. The model shows the feasibility of including genomic knowledge into a biogeochemical model and is suited to understanding and predicting changes in marine microbial community structure and function, and to simulating the biological response to rapid environmental changes.

scholarly journals Comparative Analysis of Fecal Microbiota of Grazing Mongolian Cattle from Different Regions in Inner Mongolia, China

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1938
Author(s):  
Han Aricha ◽  
Huasai Simujide ◽  
Chunjie Wang ◽  
Jian Zhang ◽  
Wenting Lv ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Gut Microbiota ◽  
Inner Mongolia ◽  
Alpha Diversity ◽  
Fecal Microbiota ◽  
Composition Analysis ◽  
Geographical Factors ◽  
Rrna Sequencing ◽  
Xilingol Grassland

Mongolian cattle from China have strong adaptability and disease resistance. We aimed to compare the gut microbiota community structure and diversity in grazing Mongolian cattle from different regions in Inner Mongolia and to elucidate the influence of geographical factors on the intestinal microbial community structure. We used high throughput 16S rRNA sequencing to analyze the fecal microbial community and diversity in samples from 60 grazing Mongolian cattle from Hulunbuir Grassland, Xilingol Grassland, and Alxa Desert. A total of 2,720,545 high-quality reads and sequences that were 1,117,505,301 bp long were obtained. Alpha diversity among the three groups showed that the gut microbial diversity in Mongolian cattle in the grasslands was significantly higher than that in the desert. The dominant phyla were Firmicutes and Bacteroidetes, whereas Verrucomicrobia presented the highest abundance in the gut of cattle in the Alxa Desert. The gut bacterial communities in cattle from the grasslands versus the Alxa Desert were distinctive, and those from the grasslands were closely clustered. Community composition analysis revealed significant differences in species diversity and richness. Overall, the composition of the gut microbiota in Mongolian cattle is affected by geographical factors. Gut microbiota may play important roles in the geographical adaptations of Mongolian cattle.

scholarly journals Straw-Based Biopurification Systems to Remove Ibuprofen, Diclofenac and Triclosan from Wastewaters: Dominant Microbial Communities

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1507
Author(s):  
Laura Delgado-Moreno ◽  
Pieter van Dillewijn ◽  
Rogelio Nogales ◽  
Esperanza Romero
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Point Source ◽  
Relative Abundance ◽  
Alpha Diversity ◽  
Microbial Structure ◽  
Methyl Triclosan ◽  
Source Contamination ◽  
Biopurification Systems ◽  
Olive Mill

The continued discharge of pharmaceuticals and personal care products (PPCPs) into the environment due to their widespread use and the lack of effective systems for their removal from water is a global problem. In this study, the dissipation of ibuprofen, diclofenac and triclosan added simultaneously in biopurification systems (BPSs) with different compositions and their effect on the microbial community structure was analysed. Three BPSs, constituted by mixtures of soil (S), peat (P), or raw wet olive mill cake (A) or its vermicompost (V) and straw (S) were prepared (SPS, SAS and SVS). Sorption and degradation experiments were carried out. After 84 days of incubation, more than 85% of each PPCP applied had dissipated. Methyl-triclosan was determined to be highest in the SVS biomixture. Biomixtures with lower C/N ratio and higher alpha diversity were the most effective in the removal of PPCPs. Initially, the BPS biomixtures showed a different microbial structure dominated by Proteobacteria, Actinobacteria and Bacteroidetes but after addition of PPCPs, a similar pattern was observed in the relative abundance of the phylum Chloroflexi, the class Sphingobacteriia and the genus Brevundimonas. These biopurification systems can be useful to prevent point source contamination due to the disposal of PPCP-contaminated waters.

scholarly journals Active Anaerobic Archaeal Methanotrophs in Recently Emerged Cold Seeps of Northern South China Sea

2020 ◽  
Vol 11 ◽  
Author(s):  
Tingting Zhang ◽  
Xi Xiao ◽  
Songze Chen ◽  
Jing Zhao ◽  
Zongheng Chen ◽  
...  
Keyword(s):  
Community Structure ◽  
South China Sea ◽  
Bacterial Communities ◽  
Northern South China Sea ◽  
Sulfate Reducing Bacteria ◽  
Cold Seep ◽  
Cold Seeps ◽  
Sulfate Reducing ◽  
Reducing Bacteria ◽  
Rna And Dna

Cold seep ecosystems are developed from methane-rich fluids in organic rich continental slopes, which are the source of various dense microbial and faunal populations. Extensive studies have been conducted on microbial populations in this unique environment; most of them were based on DNA, which could not resolve the activity of extant organisms. In this study, RNA and DNA analyses were performed to evaluate the active archaeal and bacterial communities and their network correlations, particularly those participating in the methane cycle at three sites of newly developed cold seeps in the northern South China Sea (nSCS). The results showed that both archaeal and bacterial communities were significantly different at the RNA and DNA levels, revealing a higher abundance of methane-metabolizing archaea and sulfate-reducing bacteria in RNA sequencing libraries. Site ROV07-01, which exhibited extensive accumulation of deceased Calyptogena clam shells, was highly developed, and showed diverse and active anaerobic archaeal methanotrophs (ANME)-2a/b and sulfate-reducing bacteria from RNA libraries. Site ROV07-02, located near carbonate crusts with few clam shell debris, appeared to be poorly developed, less anaerobic and less active. Site ROV05-02, colonized by living Calyptogena clams, could likely be intermediary between ROV07-01 and ROV07-02, showing abundant ANME-2dI and sulfate-reducing bacteria in RNA libraries. The high-proportions of ANME-2dI, with respect to ANME-2dII in the site ROV07-01 was the first report from nSCS, which could be associated with recently developed cold seeps. Both ANME-2dI and ANME-2a/b showed close networked relationships with sulfate-reducing bacteria; however, they were not associated with the same microbial operational taxonomic units (OTUs). Based on the geochemical gradients and the megafaunal settlements as well as the niche specificities and syntrophic relationships, ANMEs appeared to change in community structure with the evolution of cold seeps, which may be associated with the heterogeneity of their geochemical processes. This study enriched our understanding of more active sulfate-dependent anaerobic oxidation of methane (AOM) in poorly developed and active cold seep sediments by contrasting DNA- and RNA-derived community structure and activity indicators.

scholarly journals Monitoring and Surveillance of Aerial Mycobiota of Rice Paddy through DNA Metabarcoding and qPCR

2020 ◽  
Vol 6 (4) ◽  
pp. 372
Author(s):  
Sara Franco Ortega ◽  
Ilario Ferrocino ◽  
Ian Adams ◽  
Simone Silvestri ◽  
Davide Spadaro ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Diversity Index ◽  
Alpha Diversity ◽  
Its Region ◽  
Rice Paddy ◽  
Bipolaris Oryzae ◽  
Wiener Diversity Index ◽  
Abundant Otus ◽  
Dna Metabarcoding ◽  
Community Complexity

The airborne mycobiota has been understudied in comparison with the mycobiota present in other agricultural environments. Traditional, culture-based methods allow the study of a small fraction of the organisms present in the atmosphere, thus missing important information. In this study, the aerial mycobiota in a rice paddy has been examined during the cropping season (from June to September 2016) using qPCRs for two important rice pathogens (Pyricularia oryzae and Bipolaris oryzae) and by using DNA metabarcoding of the fungal ITS region. The metabarcoding results demonstrated a higher alpha diversity (Shannon–Wiener diversity index H′ and total number of observed species) at the beginning of the trial (June), suggesting a higher level of community complexity, compared with the end of the season. The main taxa identified by HTS analysis showed a shift in their relative abundance that drove the cluster separation as a function of time and temperature. The most abundant OTUs corresponded to genera such as Cladosporium, Alternaria, Myrothecium, or Pyricularia. Changes in the mycobiota composition were clearly dependent on the average air temperature with a potential impact on disease development in rice. In parallel, oligotyping analysis was performed to obtain a sub-OTU identification which revealed the presence of several oligotypes of Pyricularia and Bipolaris with relative abundance changing during monitoring.

scholarly journals Revealing Cryptic Changes of Cyanobacterial Community Structure in Two Eutrophic Lakes Using eDNA Sequencing

2020 ◽  
Vol 17 (17) ◽  
pp. 6356
Author(s):  
Yongguang Jiang ◽  
Peng Xiao ◽  
Gongliang Yu ◽  
Gaofei Song ◽  
Renhui Li
Keyword(s):  
Community Structure ◽  
High Throughput Sequencing ◽  
Environmental Dna ◽  
Cyanobacterial Blooms ◽  
Erhai Lake ◽  
Water Safety ◽  
Cyanobacterial Community ◽  
Eutrophic Lakes ◽  
Abundant Otus ◽  
Cyanobacterial Diversity

Harmful cyanobacterial blooms pose a risk to human health worldwide. To enhance understanding on the bloom-forming mechanism, the spatiotemporal changes in cyanobacterial diversity and composition in two eutrophic lakes (Erhai Lake and Lushui Reservoir) of China were investigated from 2010 to 2011 by high-throughput sequencing of environmental DNA. For each sample, 118 to 260 cpcBA-IGS operational taxonomic units (OTUs) were obtained. Fifty-two abundant OTUs were identified, which made up 95.2% of the total sequences and were clustered into nine cyanobacterial groups. Although the cyanobacterial communities of both lakes were mainly dominated by Microcystis, Erhai Lake had a higher cyanobacterial diversity. The abundance of mixed Nostocales species was lower than that of Microcystis, whereas Phormidium and Synechococcus were opportunistically dominant. The correlation between the occurrence frequency and relative abundance of OTUs was poorly fitted by the Sloan neutral model. Deterministic processes such as phosphorus availability were shown to have significant effects on the cyanobacterial community structure in Erhai Lake. In summary, the Microcystis-dominated cyanobacterial community was mainly affected by the deterministic process. Opportunistically dominant species have the potential to replace Microcystis and form blooms in eutrophic lakes, indicating the necessity to monitor these species for drinking water safety.

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