Structures of free-living and protozoa-associated methanogen communities in the bovine rumen differ according to comparative analysis of 16S rRNA and mcrA genes

Microbiology ◽  
2012 ◽  
Vol 158 (7) ◽  
pp. 1808-1817 ◽  
Author(s):  
Lisa D. Tymensen ◽  
Karen A. Beauchemin ◽  
Tim A. McAllister
2006 ◽  
Vol 34 (Web Server) ◽  
pp. W394-W399 ◽  
Author(s):  
T. Z. DeSantis ◽  
P. Hugenholtz ◽  
K. Keller ◽  
E. L. Brodie ◽  
N. Larsen ◽  
...  

Author(s):  
Martin Hahn ◽  
Andrea Huemer ◽  
Alexandra Pitt ◽  
Matthias Hoetzinger

Current knowledge on environmental distribution and taxon richness of free-living bacteria is mainly based on cultivation-independent investigations employing 16S rRNA gene sequencing methods. Yet, 16S rRNA genes are evolutionarily rather conserved, resulting in limited taxonomic and ecological resolutions provided by this marker. We used a faster evolving protein-encoding marker to reveal ecological patterns hidden within a single OTU defined by >99% 16S rRNA sequence similarity. The studied taxon, subcluster PnecC of the genus Polynucleobacter, represents a ubiquitous group of planktonic freshwater bacteria with cosmopolitan distribution, which is very frequently detected by diversity surveys of freshwater systems. Based on genome taxonomy and a large set of genome sequences, a sequence similarity threshold for delineation of species-like taxa could be established. In total, 600 species-like taxa were detected in 99 freshwater habitats scattered across three regions representing a latitudinal range of 3400 km (42°N to 71°N) and a pH gradient of 4.2 to 8.6. Besides the unexpectedly high richness, the increased taxonomic resolution revealed structuring of Polynucleobacter communities by a couple of macroecological trends, which was previously only demonstrated for phylogenetically much broader groups of bacteria. A unexpected pattern was the almost complete compositional separation of Polynucleobacter communities of Ca-rich and Ca-poor habitats, which strongly resembled the vicariance of plant species on silicate and limestone soils. The presented new cultivation-independent approach opened a window to an incredible, previously unseen diversity, and enables investigations aiming on deeper understanding of how environmental conditions shape bacterial communities and drive evolution of free-living bacteria.


2019 ◽  
Vol 14 (1) ◽  
pp. 288-298
Author(s):  
Siyue Zhao ◽  
Caiwu Li ◽  
Guo Li ◽  
Shengzhi Yang ◽  
Yingming Zhou ◽  
...  

AbstractThe giant panda (GP) was the most endangered species in China, and gut microbiota plays a vital role in host health. To determine the differences of the gut microbiota among the male, female and pregnant GPs, a comparative analysis of gut microbiota in GPs was carried out by 16S rRNA and ITS high-throughput sequencing. In 16S rRNA sequencing, 435 OTUs, 17 phyla and 182 genera were totally detected. Firmicutes (53.6%) was the predominant phylum followed by Proteobacteria (37.8%) and Fusobacteria (7.1%). Escherichia/Shigella (35.9%) was the most prevalent genus followed by Streptococcus (25.9%) and Clostridium (11.1%). In ITS sequencing, 920 OTUs, 6 phyla and 322 genera were also detected. Ascomycota (71.3%) was the predominant phylum followed by Basidiomycota (28.4%) and Zygomycota (0.15%). Purpureocillium (4.4%) was the most prevalent genus followed by Cladosporium (2.5%) and Pezicula (2.4%). Comparative analysis indicated that the male GPs harbor a higher abundance of phylum Firmicutes than female GPs with the contribution from genus Streptococcus. Meanwhile, the female GPs harbor a higher abundance of phylum Proteobacteria than male GPs with the contribution from genus Escherichia/ Shigella. In addition, the shift in bacteria from female to pregnant GPs indicated that phylum Firmicutes increased significantly with the contribution from Clostridium in the gut, which may provide an opportunity to study possible associations with low reproduction of the GPs.


2005 ◽  
Vol 71 (4) ◽  
pp. 2162-2169 ◽  
Author(s):  
Hideyuki Tamaki ◽  
Yuji Sekiguchi ◽  
Satoshi Hanada ◽  
Kazunori Nakamura ◽  
Nakao Nomura ◽  
...  

ABSTRACT Comparative analysis of bacterial diversity in freshwater sediment collected from a shallow eutrophic lake was performed by using 16S rRNA gene clone library and improved cultivation-based techniques. Our study demonstrated that the use of gellan gum as a gelling reagent instead of agar was more effective at increasing culturability, cultivating a diverse array of novel microbes, and reducing the gaps of the results between molecular and cultivation-based analyses.


2013 ◽  
Vol 2 (4) ◽  
pp. 541-552 ◽  
Author(s):  
Bibiana G. Crespo ◽  
Thomas Pommier ◽  
Beatriz Fernández‐Gómez ◽  
Carlos Pedrós‐Alió

2006 ◽  
Vol 56 (3) ◽  
pp. 625-628 ◽  
Author(s):  
Dores G. Cirne ◽  
Osvaldo D. Delgado ◽  
Sankar Marichamy ◽  
Bo Mattiasson

A strictly anaerobic, mesophilic, endospore-forming, lipolytic bacterium, designated strain R1T, was isolated from bovine rumen fluid and characterized. Cells of this isolate were Gram-positive, non-motile rods that formed spherical terminal spores. The overall biochemical and physiological characteristics indicated that this strain should be placed in the genus Clostridium. The strain grew at temperatures between 25 and 47 °C (optimum, 37 °C), at pH between 5·0 and 8·5 (optimum pH 5·5–7·0) and in NaCl concentrations of 0–3 % (w/v). The isolate was not able to utilize glucose or other carbohydrates as carbon sources. The DNA G+C content was 31·2 mol%. Sequence analysis of the 16S rRNA gene of R1T revealed that it has the closest match (98 % similarity) with Clostridium tetanomorphum DSM 4474T. The highest levels of DNA–DNA relatedness of the isolate were 61·9 and 54·3 % with Clostridium pascui DSM 10365T and C. tetanomorphum DSM 4474T, respectively. Based on 16S rRNA gene sequence similarity, phylogenetic analysis, DNA G+C content, DNA–DNA hybridization data and distinct phenotypic characteristics, strain R1T (=DSM 17049T=CCUG 50446T) was classified in the genus Clostridium, as a member of a novel species, for which the name Clostridium lundense sp. nov. is proposed.


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