scholarly journals Geochemical and Temporal Influences on the Enrichment of Acidophilic Iron-Oxidizing Bacterial Communities

2016 ◽  
Vol 82 (12) ◽  
pp. 3611-3621 ◽  
Author(s):  
Yizhi Sheng ◽  
Kyle Bibby ◽  
Christen Grettenberger ◽  
Bradley Kaley ◽  
Jennifer L. Macalady ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Temporal Distance ◽  
Fed Batch ◽  
Content Type ◽  
Term Operation ◽  
Geochemical Conditions ◽  
Suspended Growth

ABSTRACTTwo acid mine drainage (AMD) sites in the Appalachian bituminous coal basin were selected to enrich for Fe(II)-oxidizing microbes and measure rates of low-pH Fe(II) oxidation in chemostatic bioreactors. Microbial communities were enriched for 74 to 128 days in fed-batch mode, then switched to flowthrough mode (additional 52 to 138 d) to measure rates of Fe(II) oxidation as a function of pH (2.1 to 4.2) and influent Fe(II) concentration (80 to 2,400 mg/liter). Biofilm samples were collected throughout these operations, and the microbial community structure was analyzed to evaluate impacts of geochemistry and incubation time. Alpha diversity decreased as the pH decreased and as the Fe(II) concentration increased, coincident with conditions that attained the highest rates of Fe(II) oxidation. The distribution of the seven most abundant bacterial genera could be explained by a combination of pH and Fe(II) concentration.Acidithiobacillus,Ferrovum,Gallionella,Leptospirillum,Ferrimicrobium,Acidiphilium, andAcidocellawere all found to be restricted within specific bounds of pH and Fe(II) concentration. Temporal distance, defined as the cumulative number of pore volumes from the start of flowthrough mode, appeared to be as important as geochemical conditions in controlling microbial community structure. Both alpha and beta diversities of microbial communities were significantly correlated to temporal distance in the flowthrough experiments. Even after long-term operation under nearly identical geochemical conditions, microbial communities enriched from the different sites remained distinct. While these microbial communities were enriched from sites that displayed markedly different field rates of Fe(II) oxidation, rates of Fe(II) oxidation measured in laboratory bioreactors were essentially the same. These results suggest that the performance of suspended-growth bioreactors for AMD treatment may not be strongly dependent on the inoculum used for reactor startup.IMPORTANCEThis study showed that different microbial communities enriched from two sites maintained distinct microbial community traits inherited from their respective seed materials. Long-term operation (up to 128 days of fed-batch enrichment followed by up to 138 days of flowthrough experiments) of these two systems did not lead to the same, or even more similar, microbial communities. However, these bioreactors did oxidize Fe(II) and remove total iron [Fe(T)] at very similar rates. These results suggest that the performance of suspended-growth bioreactors for AMD treatment may not be strongly dependent on the inoculum used for reactor startup. This would be advantageous, because system performance should be well constrained and predictable for many different sites.

scholarly journals Defining the Core Citrus Leaf- and Root-Associated Microbiota: Factors Associated with Community Structure and Implications for Managing Huanglongbing (Citrus Greening) Disease

2017 ◽  
Vol 83 (11) ◽  
Author(s):  
Ryan A. Blaustein ◽  
Graciela L. Lorca ◽  
Julie L. Meyer ◽  
Claudio F. Gonzalez ◽  
Max Teplitski
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Illumina Sequencing ◽  
Symptom Severity ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Content Type ◽  
The Core ◽  
Symptom Progression

ABSTRACTStable associations between plants and microbes are critical to promoting host health and productivity. The objective of this work was to test the hypothesis that restructuring of the core microbiota may be associated with the progression of huanglongbing (HLB), the devastating citrus disease caused byLiberibacter asiaticus,Liberibacter americanus, andLiberibacter africanus. The microbial communities of leaves (n= 94) and roots (n= 79) from citrus trees that varied by HLB symptom severity, cultivar, location, and season/time were characterized with Illumina sequencing of 16S rRNA genes. The taxonomically rich communities contained abundant core members (i.e., detected in at least 95% of the respective leaf or root samples), some overrepresented site-specific members, and a diverse community of low-abundance variable taxa. The composition and diversity of the leaf and root microbiota were strongly associated with HLB symptom severity and location; there was also an association with host cultivar. The relative abundance ofLiberibacterspp. among leaf microbiota positively correlated with HLB symptom severity and negatively correlated with alpha diversity, suggesting that community diversity decreases as symptoms progress. Network analysis of the microbial community time series identified a mutually exclusive relationship betweenLiberibacterspp. and members of theBurkholderiaceae,Micromonosporaceae, andXanthomonadaceae. This work confirmed several previously described plant disease-associated bacteria, as well as identified new potential implications for biological control. Our findings advance the understanding of (i) plant microbiota selection across multiple variables and (ii) changes in (core) community structure that may be a precondition to disease establishment and/or may be associated with symptom progression.IMPORTANCEThis study provides a comprehensive overview of the core microbial community within the microbiomes of plant hosts that vary in extent of disease symptom progression. With 16S Illumina sequencing analyses, we not only confirmed previously described bacterial associations with plant health (e.g., potentially beneficial bacteria) but also identified new associations and potential interactions between certain bacteria and an economically important phytopathogen. The importance of core taxa within broader plant-associated microbial communities is discussed.

Impacts of long-term fertilization on the soil microbial communities in double-cropped paddy fields

2018 ◽  
Vol 156 (7) ◽  
pp. 857-864 ◽  
Author(s):  
H. M. Tang ◽  
Y. L. Xu ◽  
X. P. Xiao ◽  
C. Li ◽  
W. Y. Li ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Soil Microbial Communities ◽  
Chemical Fertilizer ◽  
Soil Microbial Community Structure ◽  
Soil Microbial

AbstractThe response of soil microbial communities to soil quality changes is a sensitive indicator of soil ecosystem health. The current work investigated soil microbial communities under different fertilization treatments in a 31-year experiment using the phospholipid fatty acid (PLFA) profile method. The experiment consisted of five fertilization treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice (Oryza sativaL.) straw residue and chemical fertilizer (RF), low manure rate and chemical fertilizer (LOM), and high manure rate and chemical fertilizer (HOM). Soil samples were collected from the plough layer and results indicated that the content of PLFAs were increased in all fertilization treatments compared with the control. The iC15:0 fatty acids increased significantly in MF treatment but decreased in RF, LOM and HOM, while aC15:0 fatty acids increased in these three treatments. Principal component (PC) analysis was conducted to determine factors defining soil microbial community structure using the 21 PLFAs detected in all treatments: the first and second PCs explained 89.8% of the total variance. All unsaturated and cyclopropyl PLFAs except C12:0 and C15:0 were highly weighted on the first PC. The first and second PC also explained 87.1% of the total variance among all fertilization treatments. There was no difference in the first and second PC between RF and HOM treatments. The results indicated that long-term combined application of straw residue or organic manure with chemical fertilizer practices improved soil microbial community structure more than the mineral fertilizer treatment in double-cropped paddy fields in Southern China.

scholarly journals Effect of Start-Up Strategies and Electrode Materials on Carbon Dioxide Reduction on Biocathodes

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Soroush Saheb-Alam ◽  
Abhijeet Singh ◽  
Malte Hermansson ◽  
Frank Persson ◽  
Anna Schnürer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Electrode Materials ◽  
Microbial Community Composition ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
Cathodic Current ◽  
Content Type ◽  
Term Operation ◽  
Start Up

ABSTRACT The enrichment of CO 2 -reducing microbial biocathodes is challenging. Previous research has shown that a promising approach could be to first enrich bioanodes and then lower the potential so the electrodes are converted into biocathodes. However, the effect of such a transition on the microbial community on the electrode has not been studied. The goal of this study was thus to compare the start-up of biocathodes from preenriched anodes with direct start-up from bare electrodes and to investigate changes in microbial community composition. The effect of three electrode materials on the long-term performance of the biocathodes was also investigated. In this study, preenrichment of acetate-oxidizing bioanodes did not facilitate the start-up of biocathodes. It took about 170 days for the preenriched electrodes to generate substantial cathodic current, compared to 83 days for the bare electrodes. Graphite foil and carbon felt cathodes produced higher current at the beginning of the experiment than did graphite rods. However, all electrodes produced similar current densities at the end of the over 1-year-long study (2.5 A/m 2 ). Methane was the only product detected during operation of the biocathodes. Acetate was the only product detected after inhibition of the methanogens. Microbial community analysis showed that Geobacter sp. dominated the bioanodes. On the biocathodes, the Geobacter sp. was succeeded by Methanobacterium spp., which made up more than 80% of the population. After inhibition of the methanogens, Acetobacterium sp. became dominant on the electrodes (40% relative abundance). The results suggested that bioelectrochemically generated H 2 acted as an electron donor for CO 2 reduction. IMPORTANCE In microbial electrochemical systems, living microorganisms function as catalysts for reactions on the anode and/or the cathode. There is a variety of potential applications, ranging from wastewater treatment and biogas generation to production of chemicals. Systems with biocathodes could be used to reduce CO 2 to methane, acetate, or other high-value chemicals. The technique can be used to convert solar energy to chemicals. However, enriching biocathodes that are capable of CO 2 reduction is more difficult and less studied than enriching bioanodes. The effect of different start-up strategies and electrode materials on the microbial communities that are enriched on biocathodes has not been studied. The purpose of this study was to investigate two different start-up strategies and three different electrode materials for start-up and long-term operation of biocathodes capable of reducing CO 2 to valuable biochemicals.

scholarly journals A Long-Standing Complex Tropical Dipole Shapes Marine Microbial Biogeography

2018 ◽  
Vol 84 (18) ◽  
Author(s):  
Wei Yan ◽  
Rui Zhang ◽  
Nianzhi Jiao
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Large Scale ◽  
Community Dynamics ◽  
Anticyclonic Eddy ◽  
Cyclonic Eddy ◽  
Content Type ◽  
Microbial Community Dynamics ◽  
Biogeographic Provinces

ABSTRACTMicrobial population size, production, diversity, and community structure are greatly influenced by the surrounding physicochemical conditions, such as large-scale biogeographic provinces and water masses. An oceanic mesoscale dipole consists of a cyclonic eddy and an anticyclonic eddy. Dipoles occur frequently in the ocean and usually last from a few days to several months; they have significant impacts on local and global oceanic biological, ecological, and geochemical processes. To better understand how dipoles shape microbial communities, we examined depth-resolved distributions of microbial communities across a dipole in the South China Sea. Our data demonstrated that the dipole had a substantial influence on microbial distributions, community structure, and functional groups both vertically and horizontally. Large alpha and beta diversity differences were observed between anticyclonic and cyclonic eddies in surface and subsurface layers, consistent with distribution changes of major bacterial groups in the dipole. The dipole created uplift, downward transport, enrichment, depletion, and horizontal transport effects. We also found that the edge of the dipole might induce strong subduction, indicated by the presence ofProchlorococcusandSynechococcusin deep waters. Our findings suggest that dipoles, with their unique characteristics, might act as a driver for microbial community dynamics.IMPORTANCEOceanic dipoles, which consist of a cyclonic eddy and an anticyclonic eddy together, are among the most contrasted phenomena in the ocean. Dipoles generate strong vertical mixing and horizontal advection, inducing biological responses. This study provides vertical profiles of microbial abundance, diversity, and community structure in a mesoscale dipole. We identify the links between the physical oceanography and microbial oceanography and demonstrate that the dipole, with its unique features, could act as a driver for microbial community dynamics, which may have large impacts on both the local and global marine biogeochemical cycles.

scholarly journals Study of Periplaneta Americana Microbial Community Structure and Diversity by 16S rRNA High-Throughput Sequencing

2017 ◽  
Vol 2 (4) ◽  
pp. 350
Author(s):  
Zhuang Zhi Chen ◽  
Xiu Mei Wu ◽  
Yong Mei Shen ◽  
Cheng Gong Li ◽  
Kai Ge Xu ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
16S Rrna ◽  
Microbial Communities ◽  
High Throughput ◽  
Microbial Community Structure ◽  
Periplaneta Americana ◽  
High Throughput Sequencing ◽  
Shannon Index

<p><strong><em>Objective: </em></strong><em>The present study probes into the microbial community structure in Periplaneta americana under different breeding conditions, using 16S rRNA high-throughput sequencing technique, in the hope of finding the microbial community structure in Periplaneta americana and their diversity under different breeding conditions. </em></p><p><strong><em>Methods:</em></strong><em> In this study, we extract the microbial metagenomic DNA of 5 groups of Periplaneta americana which under different breeding conditions. Using lllumina Miseq sequencing platform, two-terminal sequencing of V3-V4 regions of 16S rRNA were sequenced; diversity of community structure was analyzed using the softwares such as fastqc, </em><em>QIIME, </em><em>PyNAST, fasttree and R language.</em></p><p><strong><em>Results: </em></strong><em>Shannon index of samples in SG group was lower than that of the other four groups, significantly lower than that of DB group (P&lt;0.05), but not significantly different from other groups. This suggested that the intake of a mixed fodder with high sugar, high fat and high protein by Periplaneta americana can reduce the diversity of microbial communities. Our findings showed that breeding intervention with different fodders may cause differences in the contents of Bacteroidetes, Proteobacteria and Firmicutes in Periplaneta americana. Results showed that long-term intake of lots of sucrose and fat may increase the proportion of Bacteroidetes in Periplaneta americana; and long-term intake of lots of sucrose may reduce the proportion of Proteobacteria in Periplaneta americana; and long-term intake of lots of fat may reduce the proportion of Firmicutes in Periplaneta americana. Two major dominant bacterial genera in all samples were Blattabacterium and Rickettsiella. But different feeding interventions can change the proportions of Blattabacterium and Rickettsiella.</em></p><p><strong><em>Conclusion:</em></strong><em> Periplaneta americana has a complex microbial community structure. Different feeding conditions may change the microbial community structure of Periplaneta americana. An important bacterial genus in Periplaneta americana, Blattabacterium is positively correlated with the intake of sucrose- and fat-rich fodder. In the breeding process of Periplaneta americana, adding sucrose and fat to fodder may increase the content and proportion of Blattabacterium in microbial communities.</em></p>

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

2013 ◽  
Vol 80 (1) ◽  
pp. 177-183 ◽  
Author(s):  
Lavane Kim ◽  
Eulyn Pagaling ◽  
Yi Y. Zuo ◽  
Tao Yan
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Bacterial Species ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
Rrna Gene ◽  
Content Type ◽  
Property Change ◽  
And Control ◽  
Start Ups

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

Phylum-Specific Primer Design and Implication in Quantification of the Microbial Community Structure in GuJingGong Pit Mud

2014 ◽  
Vol 1051 ◽  
pp. 311-316 ◽  
Author(s):  
Xi Mei Luo ◽  
Zhi Lei Gao ◽  
Hui Min Zhang ◽  
An Jun Li ◽  
Hong Kui He ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Real Time Quantitative Pcr ◽  
Sequencing Technologies ◽  
Specific Pcr ◽  
Pit Mud ◽  
Almost All ◽  
Polymerase Chain Reaction Primers

In recent years, despite the significant improvement of sequencing technologies such as the pyrosequencing, rapid evaluation of microbial community structures remains very difficult because of the abundance and complexity of organisms in almost all natural microbial communities. In this paper, a group of phylum-specific primers were elaborately designed based on a single nucleotide discrimination technology to quantify the main microbial community structure from GuJingGong pit mud samples using the real-time quantitative PCR (qPCR). Specific PCR (polymerase chain reaction) primers targeting a particular group would provide promising sensitivity and more in-depth assessment of microbial communities.

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