Higher seasonal variation of actinobacterial communities than spatial heterogeneity in the surface sediments of Taihu Lake, China

2013 ◽  
Vol 59 (5) ◽  
pp. 353-358 ◽  
Author(s):  
Jianjun Wang ◽  
Yong Zhang ◽  
Zhengkui Li ◽  
Ji Shen
Keyword(s):  
Seasonal Variation ◽  
Spatial Heterogeneity ◽  
Lake Sediments ◽  
Surface Sediments ◽  
Taihu Lake ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Detrended Correspondence Analysis ◽  
Rrna Gene ◽  
Clone Libraries ◽  
Principal Coordinates

Much more attention has been paid to the actinobacterial community in soils or water columns of aquatic habitats. However, there are few studies on their composition and diversity in lake sediments. Here, we used denaturing gradient gel electrophoresis and clone libraries of partial 16S rRNA gene to study the spatial variations of actinobacterial communities across 4 seasons in the surface sediments of the shallow, subtropical Taihu Lake. Cluster analysis based on fingerprints showed clear spatiotemporal variations of actinobacterial communities and higher seasonal variation than spatial heterogeneity. Based on clone libraries, this pattern was supported by the principal coordinates analysis in the phylogenetic context and by detrended correspondence analysis on the operational taxonomic unit table. Additionally, phylogenetic analysis showed that the putative freshwater-specific actinobacterial lineages (e.g., acI) were also detected in the lake sediments, which suggests that these subclusters may also adapt to the sediment environments. Summarily, our results suggested that actinobacterial communities of the surface sediments were more affected by seasonal variation than spatial heterogeneity in the intrahabitat of Taihu Lake.

scholarly journals Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen

2007 ◽  
Vol 73 (14) ◽  
pp. 4609-4618 ◽  
Author(s):  
Samuel Ohene-Adjei ◽  
Ronald M. Teather ◽  
Michael Ivan ◽  
Robert J. Forster
Keyword(s):  
Phylogenetic Analysis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Methanogenic Archaea ◽  
Type A ◽  
Negative Control ◽  
Rrna Gene ◽  
Association Patterns ◽  
Clone Libraries ◽  
Symbiotic Relationships ◽  
The Impact

ABSTRACT Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.

scholarly journals Analysis of Bacterial Communities in Soil by Use of Denaturing Gradient Gel Electrophoresis and Clone Libraries, as Influenced by Different Reverse Primers

2008 ◽  
Vol 74 (9) ◽  
pp. 2717-2727 ◽  
Author(s):  
Jolanda K. Brons ◽  
Jan Dirk van Elsas
Keyword(s):  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Soil Analysis ◽  
Rrna Gene ◽  
Sequence Information ◽  
Soil Bacterial Diversity ◽  
Clone Libraries ◽  
Gradient Gel Electrophoresis ◽  
Candidate Division ◽  
Forward Primer

ABSTRACT To assess soil bacterial diversity, PCR systems consisting of several slightly different reverse primers together with forward primer F968-GC were used along with subsequent denaturing gradient gel electrophoresis (DGGE) or clone library analyses. In this study, a set of 13 previously used and novel reverse primers was tested with the canonical forward primer as to the DGGE fingerprints obtained from grassland soil. Analysis of these DGGE profiles by GelCompar showed that they all fell into two main clusters separated by a G/A alteration at position 14 in the reverse primer used. To assess differences between the dominant bacteria amplified, we then produced four (100-membered) 16S rRNA gene clone libraries by using reverse primers with either an A or a G at position 14, designated R1401-1a, R1401-1b, R1401-2a, and R1401-2b. Subsequent sequence analysis revealed that, on the basis of the about 410-bp sequence information, all four primers amplified similar, as well as different (including novel), bacterial groups from soil. Most of the clones fell into two main phyla, Firmicutes and Proteobacteria. Within Firmicutes, the majority of the clones belonged to the genus Bacillus. Within Proteobacteria, the majority of the clones fell into the alpha or gamma subgroup whereas a few were delta and beta proteobacteria. The other phyla found were Actinobacteria, Acidobacteria, Verrucomicrobia, Chloroflexi, Gemmatimonadetes, Chlorobi, Bacteroidetes, Chlamydiae, candidate division TM7, Ferribacter, Cyanobacteria, and Deinococcus. Statistical analysis of the data revealed that reverse primers R1401-1b and R1401-1a both produced libraries with the highest diversities yet amplified different types. Their concomitant use is recommended.

The Diversity of Benthic Microorganisms in Acidic Mine Lake Sediments

2007 ◽  
Vol 20-21 ◽  
pp. 489-492
Author(s):  
Huynh A. Pham ◽  
Carolyn E. Oldham ◽  
Jason J. Plumb
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Communities ◽  
Lake Sediments ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Probable Number ◽  
Benthic Bacteria ◽  
Different Depths

The sediment microbial communities of a disused coal mine lake, Lake Kepwari (pH~4.5-5) were studied to understand how the natural microbial processes in an oligotrophic acidic mine lake system influence the iron and sulphur cycles. Most probable number (MPN) viable counts were used to enumerate the benthic bacteria at different depths. MPN results revealed an abundance of bacteria that were capable of growing in sulphate reducing medium with numbers in the range of 1 × 107 – 1 × 108 cells.g-1 of wet sediment. In contrast, MPN results showed much lower numbers of bacteria that were capable of growing in ferric reducing medium with 1 × 102 – 2 × 103 cells.g-1 of wet sediment detected. Serial decimal dilution cultures were used to isolate pure strains of benthic bacteria. Strains HP1, HP2 and HP3 were isolated from benthic lake sediments at 18 m, 0 m and 10 m water depths respectively. 16S rRNA gene sequence analysis of strain HP1 showed that the strain belonged to the genus Enterobacter, strain HP2 belonged to the Order Rhizobiales and strain HP3 belonged to the sub-order Micrococcineae. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene fragments was used to profile the diversity of the benthic microbial communities at different depths. DGGE profiling of benthic sediments revealed that sediments contained mostly members of the Proteobacteria, Actinobacteria and Firmicutes phyla.

Culture-dependent and -independent approaches establish the complexity of a PAH-degrading microbial consortium

2005 ◽  
Vol 51 (11) ◽  
pp. 897-909 ◽  
Author(s):  
Marc Viñas ◽  
Jordi Sabaté ◽  
Caterina Guasp ◽  
Jorge Lalucat ◽  
Anna M Solanas
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Consortium ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Sole Source ◽  
Rrna Gene ◽  
Dominant Group ◽  
Clone Libraries ◽  
Variable Regions ◽  
Culture Dependent

A microbial consortium (AM) obtained by sequential enrichment in liquid culture with a polycyclic aromatic hydrocarbon (PAH) mixture of three- and four-ringed PAHs as a sole source of carbon and energy was examined using a triple-approach method based on various cultivation strategies, denaturing gradient gel electrophoresis (DGGE), and the screening of 16S and 18S rRNA gene clone libraries. Eleven different sequences by culture-dependent techniques and seven by both DGGE and clone libraries were obtained. The comparison of three variable regions (V3–V5) of the 16S rRNA gene between the sequences obtained yielded 19 different microbial components. Proteobacteria were the dominant group, representing 83% of the total, while the Cytophaga–Flexibacter–Bacteroides group (CFB) was 11% and the Ascomycota fungi 6%. β-Proteobacteria were predominant in the DGGE and clone library methods, whereas they were a minority in culturable strains. The highest diversity and number of noncoincident sequences were achieved by the cultivation method that showed members of the α-, β-, and γ-Proteobacteria; CFB bacterial group; and Asco mycota fungi. Only six of the 11 strains isolated showed PAH-degrading capability. The bacterial strain (AMS7) and the fungal strain (AMF1), which were similar to Sphingomonas sp. and Fusarium sp., respectively, achieved the greatest PAH depletion. The results indicate that polyphasic assessment is necessary for a proper understanding of the composition of a microbial consortium.Key words: microbial consortium, microbial diversity, PAHs, DGGE, 16S rRNA gene.

scholarly journals Changes in Bacterial Communities of the Marine Sponge Mycale laxissima on Transfer into Aquaculture†

2007 ◽  
Vol 74 (4) ◽  
pp. 1209-1222 ◽  
Author(s):  
Naglaa M. Mohamed ◽  
Julie J. Enticknap ◽  
Jayme E. Lohr ◽  
Scott M. McIntosh ◽  
Russell T. Hill
Keyword(s):  
16S Rrna ◽  
Marine Sponge ◽  
Bacterial Communities ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Molecular Techniques ◽  
Rrna Gene ◽  
Surrounding Water ◽  
Clone Libraries ◽  
Recirculating Aquaculture Systems ◽  
Mycale Laxissima

ABSTRACT The changes in bacterial communities associated with the marine sponge Mycale laxissima on transfer to aquaculture were studied using culture-based and molecular techniques. M. laxissima was maintained alive in flowthrough and closed recirculating aquaculture systems for 2 years and 1 year, respectively. The bacterial communities associated with wild and aquacultured sponges, as well as the surrounding water, were assessed using 16S rRNA gene clone library analysis and denaturing gradient gel electrophoresis (DGGE). Bacterial richness and diversity were measured using DOTUR computer software, and clone libraries were compared using S-LIBSHUFF. DGGE analysis revealed that the diversity of the bacterial community of M. laxissima increased when sponges were maintained in aquaculture and that bacterial communities associated with wild and aquacultured M. laxissima were markedly different than those of the corresponding surrounding water. Clone libraries of bacterial 16S rRNA from sponges confirmed that the bacterial communities changed during aquaculture. These communities were significantly different than those of seawater and aquarium water. The diversity of bacterial communities associated with M. laxissima increased significantly in aquaculture. Our work shows that it is important to monitor changes in bacterial communities when examining the feasibility of growing sponges in aquaculture systems because these communities may change. This could have implications for the health of sponges or for the production of bioactive compounds by sponges in cases where these compounds are produced by symbiotic bacteria rather than by the sponges themselves.

scholarly journals Stable-Isotope Probing of Bacteria Capable of Degrading Salicylate, Naphthalene, or Phenanthrene in a Bioreactor Treating Contaminated Soil

2005 ◽  
Vol 71 (3) ◽  
pp. 1202-1209 ◽  
Author(s):  
David R. Singleton ◽  
Sabrina N. Powell ◽  
Ramiah Sangaiah ◽  
Avram Gold ◽  
Louise M. Ball ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Separation Efficiency ◽  
Stable Isotope Probing ◽  
Rrna Gene ◽  
Clone Libraries ◽  
Bacterial Populations ◽  
E Coli ◽  
Gradient Gel Electrophoresis ◽  
Heavy Fractions ◽  
K 12

ABSTRACT [13C6]salicylate, [U-13C]naphthalene, and [U-13C]phenanthrene were synthesized and separately added to slurry from a bench-scale, aerobic bioreactor used to treat soil contaminated with polycyclic aromatic hydrocarbons. Incubations were performed for either 2 days (salicylate, naphthalene) or 7 days (naphthalene, phenanthrene). Total DNA was extracted from the incubations, the “heavy” and “light” DNA were separated, and the bacterial populations associated with the heavy fractions were examined by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone libraries. Unlabeled DNA from Escherichia coli K-12 was added to each sample as an internal indicator of separation efficiency. While E. coli was not detected in most analyses of heavy DNA, a low number of E. coli sequences was recovered in the clone libraries associated with the heavy DNA fraction of [13C]phenanthrene incubations. The number of E. coli clones recovered proved useful in determining the relative amount of light DNA contamination of the heavy fraction in that sample. Salicylate- and naphthalene-degrading communities displayed similar DGGE profiles and their clone libraries were composed primarily of sequences belonging to the Pseudomonas and Ralstonia genera. In contrast, heavy DNA from the phenanthrene incubations displayed a markedly different DGGE profile and was composed primarily of sequences related to the Acidovorax genus. There was little difference in the DGGE profiles and types of sequences recovered from 2- and 7-day incubations with naphthalene, so secondary utilization of the 13C during the incubation did not appear to be an issue in this experiment.

scholarly journals Mechanistic strategies of microbial communities regulating lignocellulose deconstruction in a UK salt marsh

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Daniel R. Leadbeater ◽  
Nicola C. Oates ◽  
Joseph P. Bennett ◽  
Yi Li ◽  
Adam A. Dowle ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Molecular Mechanisms ◽  
Surface Sediments ◽  
Gene Profiling ◽  
Oxidative Enzymes ◽  
Lignocellulose Degradation ◽  
Rrna Gene ◽  
Enzymatic Mechanisms

Abstract Background Salt marshes are major natural repositories of sequestered organic carbon with high burial rates of organic matter, produced by highly productive native flora. Accumulated carbon predominantly exists as lignocellulose which is metabolised by communities of functionally diverse microbes. However, the organisms that orchestrate this process and the enzymatic mechanisms employed that regulate the accumulation, composition and permanence of this carbon stock are not yet known. We applied meta-exo-proteome proteomics and 16S rRNA gene profiling to study lignocellulose decomposition in situ within the surface level sediments of a natural established UK salt marsh. Results Our studies revealed a community dominated by Gammaproteobacteria, Bacteroidetes and Deltaproteobacteria that drive lignocellulose degradation in the salt marsh. We identify 42 families of lignocellulolytic bacteria of which the most active secretors of carbohydrate-active enzymes were observed to be Prolixibacteracea, Flavobacteriaceae, Cellvibrionaceae, Saccharospirillaceae, Alteromonadaceae, Vibrionaceae and Cytophagaceae. These families secreted lignocellulose-active glycoside hydrolase (GH) family enzymes GH3, GH5, GH6, GH9, GH10, GH11, GH13 and GH43 that were associated with degrading Spartina biomass. While fungi were present, we did not detect a lignocellulolytic contribution from fungi which are major contributors to terrestrial lignocellulose deconstruction. Oxidative enzymes such as laccases, peroxidases and lytic polysaccharide monooxygenases that are important for lignocellulose degradation in the terrestrial environment were present but not abundant, while a notable abundance of putative esterases (such as carbohydrate esterase family 1) associated with decoupling lignin from polysaccharides in lignocellulose was observed. Conclusions Here, we identify a diverse cohort of previously undefined bacteria that drive lignocellulose degradation in the surface sediments of the salt marsh environment and describe the enzymatic mechanisms they employ to facilitate this process. Our results increase the understanding of the microbial and molecular mechanisms that underpin carbon sequestration from lignocellulose within salt marsh surface sediments in situ and provide insights into the potential enzymatic mechanisms regulating the enrichment of polyphenolics in salt marsh sediments.

scholarly journals Development and Validation of a Nested-PCR-Denaturing Gradient Gel Electrophoresis Method for Taxonomic Characterization of Bifidobacterial Communities

2003 ◽  
Vol 69 (11) ◽  
pp. 6380-6385 ◽  
Author(s):  
R. Temmerman ◽  
L. Masco ◽  
T. Vanhoutte ◽  
G. Huys ◽  
J. Swings
Keyword(s):  
Nested Pcr ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Temporal Changes ◽  
Rrna Gene ◽  
Specific Pcr ◽  
Gradient Gel Electrophoresis ◽  
Species Specific ◽  
Taxonomic Characterization

ABSTRACT The taxonomic characterization of a bacterial community is difficult to combine with the monitoring of its temporal changes. None of the currently available identification techniques are able to visualize a “complete” community, whereas techniques designed for analyzing bacterial ecosystems generally display limited or labor-intensive identification potential. This paper describes the optimization and validation of a nested-PCR-denaturing gradient gel electrophoresis (DGGE) approach for the species-specific analysis of bifidobacterial communities from any ecosystem. The method comprises a Bifidobacterium-specific PCR step, followed by purification of the amplicons that serve as template DNA in a second PCR step that amplifies the V3 and V6-V8 regions of the 16S rRNA gene. A mix of both amplicons is analyzed on a DGGE gel, after which the band positions are compared with a previously constructed database of reference strains. The method was validated through the analysis of four artificial mixtures, mimicking the possible bifidobacterial microbiota of the human and chicken intestine, a rumen, and the environment, and of two fecal samples. Except for the species Bifidobacterium coryneforme and B. indicum, all currently known bifidobacteria originating from various ecosystems can be identified in a highly reproducible manner. Because no further cloning and sequencing of the DGGE bands is necessary, this nested-PCR-DGGE technique can be completed within a 24-h span, allowing the species-specific monitoring of temporal changes in the bifidobacterial community.

scholarly journals Differences in Microbial Activity and Microbial Populations of Peat Associated with Suppression of Damping-Off Disease Caused by Pythium sylvaticum

2006 ◽  
Vol 72 (10) ◽  
pp. 6452-6460 ◽  
Author(s):  
Paul J. Hunter ◽  
Geoff M. Petch ◽  
Leo A. Calvo-Bado ◽  
Tim R. Pettitt ◽  
Nick R. Parsons ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Small Subunit ◽  
Disease Suppression ◽  
Rrna Gene ◽  
Damping Off ◽  
Small Subunit Rrna ◽  
Pythium Sylvaticum ◽  
Gradient Gel Electrophoresis ◽  
Microbial Groups

ABSTRACT The microbiological characteristics associated with disease-suppressive peats are unclear. We used a bioassay for Pythium sylvaticum-induced damping-off of cress seedlings to identify conducive and suppressive peats. Microbial activity in unconditioned peats was negatively correlated with the counts of P. sylvaticum at the end of the bioassay. Denaturing gradient gel electrophoresis (DGGE) profiling and clone library analyses of small-subunit rRNA gene sequences from two suppressive and two conducive peats differed in the bacterial profiles generated and the diversity of sequence populations. There were also significant differences between bacterial sequence populations from suppressive and conducive peats. The frequencies of a number of microbial groups, including the Rhizobium-Agrobacterium group (specifically sequences similar to those for the genera Ochrobactrum and Zoogloea) and the Acidobacteria, increased specifically in the suppressive peats, although no single bacterial group was associated with disease suppression. Fungal DGGE profiles varied little over the course of the bioassay; however, two bands associated specifically with suppressive samples were detected. Sequences from these bands corresponded to Basidiomycete yeast genera. Although the DGGE profiles were similar, fungal sequence diversity also increased during the bioassay. Sequences highly similar to those of Cryptococcus increased in relative abundance during the bioassay, particularly in the suppressive samples. This study highlights the importance of using complementary approaches to molecular profiling of complex populations and provides the first report that basidiomycetous yeasts may be associated with the suppression of Pythium-induced diseases in peats.

scholarly journals Unique clade of alphaproteobacterial endosymbionts induces complete cytoplasmic incompatibility in the coconut beetle

2017 ◽  
Vol 114 (23) ◽  
pp. 6110-6115 ◽  
Author(s):  
Shun-ichiro Takano ◽  
Midori Tuda ◽  
Keiji Takasu ◽  
Naruto Furuya ◽  
Yuya Imamura ◽  
...  
Keyword(s):  
Cytoplasmic Incompatibility ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biological Control Agent ◽  
Illumina Miseq ◽  
Distinct Species ◽  
Rrna Gene ◽  
Asian Clade ◽  
The Pacific ◽  
Bacterial Endosymbionts ◽  
Unique Clade

Maternally inherited bacterial endosymbionts in arthropods manipulate host reproduction to increase the fitness of infected females. Cytoplasmic incompatibility (CI) is one such manipulation, in which uninfected females produce few or no offspring when they mate with infected males. To date, two bacterial endosymbionts,WolbachiaandCardinium, have been reported as CI inducers. OnlyWolbachiainduces complete CI, which causes 100% offspring mortality in incompatible crosses. Here we report a third CI inducer that belongs to a unique clade of Alphaproteobacteria detected within the coconut beetle,Brontispa longissima. This beetle comprises two cryptic species, the Asian clade and the Pacific clade, which show incompatibility in hybrid crosses. Different bacterial endosymbionts, a unique clade of Alphaproteobacteria in the Pacific clade andWolbachiain the Asian clade, induced bidirectional CI between hosts. The former induced complete CI (100% mortality), whereas the latter induced partial CI (70% mortality). Illumina MiSeq sequencing and denaturing gradient gel electrophoresis patterns showed that the predominant bacterium detected in the Pacific clade ofB. longissimawas this unique clade of Alphaproteobacteria alone, indicating that this endosymbiont was responsible for the complete CI. Sex distortion did not occur in any of the tested crosses. The 1,160 bp of 16S rRNA gene sequence obtained for this endosymbiont had only 89.3% identity with that ofWolbachia, indicating that it can be recognized as a distinct species. We discuss the potential use of this bacterium as a biological control agent.

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