scholarly journals Comparing faster evolving rplB and rpsC versus SSU rRNA for improved microbial community resolution

2018 ◽  
Author(s):  
Jiarong Guo ◽  
James R. Cole ◽  
C. Titus Brown ◽  
James M. Tiedje
Keyword(s):  
Alpha Diversity ◽  
Single Copy ◽  
Metagenomic Data ◽  
Universal Primers ◽  
Marker Genes ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Ribosomal Protein Genes ◽  
Protein Coding ◽  
Ssu Rrna Gene

AbstractMany conserved protein-coding core genes are single copy and evolve faster, and thus are more resolving phylogenetic markers than the standard SSU rRNA gene but their use has been precluded by the lack of universal primers. Recent advances in gene targeted assembly methods for large shotgun metagenomes make their use feasible. To evaluate this approach, we compared the variation of two single copy ribosomal protein genes, rplB and rpsC, with the SSU rRNA gene for all completed bacterial genomes in NCBI RefSeq. As expected, among pairwise comparisons of all species that belong to the same genus, 94.9% and 91.0% of the pairs of rplB and rpsC, respectively, showed more variation than did their SSU rRNA gene sequences. We used a gene-targeted assembler, Xander, to assemble rplB and rpsC from shotgun metagenomic data from rhizosphere samples of three crops: corn (annual), and Miscanthus and switchgrass (both perennials). Both protein-coding genes separated all three communities whereas the SSU rRNA gene could only separate the annual from the two perennial communities in ordination analyses. Furthermore, assembled rplB and rpsC yielded significantly higher numbers of OTUs (alpha diversity) than the SSU rRNA gene. These results confirm these faster evolving marker genes offer increased resolution of for comparative microbiome studies.

scholarly journals Evidence of independent acquisition and adaption of ultra-small bacteria to human hosts across the highly diverse yet reduced genomes of the phylum Saccharibacteria

2018 ◽  
Author(s):  
Jeffrey S. McLean ◽  
Batbileg Bor ◽  
Thao T. To ◽  
Quanhui Liu ◽  
Kristopher A. Kerns ◽  
...  
Keyword(s):  
Oral Cavity ◽  
De Novo ◽  
Gc Content ◽  
Single Copy ◽  
Small Subunit ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Ssu Rrna Gene ◽  
Human Oral Cavity

ABSTRACTRecently, we discovered that a member of the Saccharibacteria/TM7 phylum (strain TM7x) isolated from the human oral cavity, has an ultra-small cell size (200-300nm), a highly reduced genome (705 Kbp) with limited de novo biosynthetic capabilities, and a very novel lifestyle as an obligate epibiont on the surface of another bacterium 1. There has been considerable interest in uncultivated phyla, particularly those that are now classified as the proposed candidate phyla radiation (CPR) reported to include 35 or more phyla and are estimated to make up nearly 15% of the domain Bacteria. Most members of the larger CPR group share genomic properties with Saccharibacteria including reduced genomes (<1Mbp) and lack of biosynthetic capabilities, yet to date, strain TM7x represents the only member of the CPR that has been cultivated and is one of only three CPR routinely detected in the human body. Through small subunit ribosomal RNA (SSU rRNA) gene surveys, members of the Saccharibacteria phylum are reported in many environments as well as within a diversity of host species and have been shown to increase dramatically in human oral and gut diseases. With a single copy of the 16S rRNA gene resolved on a few limited genomes, their absolute abundance is most often underestimated and their potential role in disease pathogenesis is therefore underappreciated. Despite being an obligate parasite dependent on other bacteria, six groups (G1-G6) are recognized using SSU rRNA gene phylogeny in the oral cavity alone. At present, only genomes from the G1 group, which includes related and remarkably syntenic environmental and human oral associated representatives1, have been uncovered to date. In this study we systematically captured the spectrum of known diversity in this phylum by reconstructing completely novel Class level genomes belonging to groups G3, G6 and G5 through cultivation enrichment and/or metagenomic binning from humans and mammalian rumen. Additional genomes for representatives of G1 were also obtained from modern oral plaque and ancient dental calculus. Comparative analysis revealed remarkable divergence in the host-associated members across this phylum. Within the human oral cavity alone, variation in as much as 70% of the genes from nearest oral clade (AAI 50%) as well as wide GC content variation is evident in these newly captured divergent members (G3, G5 and G6) with no environmental relatives. Comparative analyses suggest independent episodes of transmission of these TM7 groups into humans and convergent evolution of several key functions during adaptation within hosts. In addition, we provide evidence from in vivo collected samples that each of these major groups are ultra-small in size and are found attached to larger cells.

scholarly journals Quantitative Metagenomic Analyses Based on Average Genome Size Normalization

2011 ◽  
Vol 77 (7) ◽  
pp. 2513-2521 ◽  
Author(s):  
Jeremy A. Frank ◽  
Søren J. Sørensen
Keyword(s):  
Microbial Communities ◽  
Genome Size ◽  
Metagenomic Data ◽  
Gene Copy ◽  
Rrna Gene ◽  
Sequence Information ◽  
Ssu Rrna ◽  
Community Members ◽  
Ssu Rrna Gene ◽  
Photosynthetic Carbon

ABSTRACTOver the past quarter-century, microbiologists have used DNA sequence information to aid in the characterization of microbial communities. During the last decade, this has expanded from single genes to microbial community genomics, or metagenomics, in which the gene content of an environment can provide not just a census of the community members but direct information on metabolic capabilities and potential interactions among community members. Here we introduce a method for the quantitative characterization and comparison of microbial communities based on the normalization of metagenomic data by estimating average genome sizes. This normalization can relieve comparative biases introduced by differences in community structure, number of sequencing reads, and sequencing read lengths between different metagenomes. We demonstrate the utility of this approach by comparing metagenomes from two different marine sources using both conventional small-subunit (SSU) rRNA gene analyses and our quantitative method to calculate the proportion of genomes in each sample that are capable of a particular metabolic trait. With both environments, to determine what proportion of each community they make up and how differences in environment affect their abundances, we characterize three different types of autotrophic organisms: aerobic, photosynthetic carbon fixers (theCyanobacteria); anaerobic, photosynthetic carbon fixers (theChlorobi); and anaerobic, nonphotosynthetic carbon fixers (theDesulfobacteraceae). These analyses demonstrate how genome proportionality compares to SSU rRNA gene relative abundance and how factors such as average genome size and SSU rRNA gene copy number affect sampling probability and therefore both types of community analysis.

scholarly journals Diversity and Abundance of Bolidophyceae (Heterokonta) in Two Oceanic Regions

1999 ◽  
Vol 65 (10) ◽  
pp. 4528-4536 ◽  
Author(s):  
Laure Guillou ◽  
Seung-Yeo Moon-Van Der Staay ◽  
Herve Claustre ◽  
Frederic Partensky ◽  
Daniel Vaulot
Keyword(s):  
High Performance ◽  
Minor Component ◽  
Small Subunit ◽  
Equatorial Pacific ◽  
Universal Primers ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Specific Probe ◽  
Equatorial Pacific Ocean ◽  
Ssu Rrna Gene

ABSTRACT The diversity and abundance of the Bolidophyceae (Heterokonta), a newly described picoplanktonic algal class which is a sister group to the diatoms, was assessed in the equatorial Pacific Ocean and in the Mediterranean Sea by culture isolation, molecular biology techniques, and pigment analyses. Eight strains of Bolidophyceae were isolated in culture from different mesotrophic and oligotrophic areas. The corresponding small subunit (SSU) rRNA gene sequences allowed us to design two probes specific for the Bolidophyceae. These probes have been used in natural samples (i) to selectively amplify and detect Bolidophyceae sequences and (ii) to quantify the relative abundance of Bolidophyceae within the picoeukaryote community. Sequences available to date indicate that the class Bolidophyceae comprises at least three different clades, two corresponding to the previously described speciesBolidomonas pacifica and Bolidomonas mediterranea and the third one corresponding to a subspecies ofB. pacifica. Amplification of the SSU rRNA gene from natural samples with universal primers and hybridization using aBolidomonas-specific probe followed by a eukaryote-specific probe allowed us to estimate the contribution of the Bolidophyceae to the eukaryotic DNA in both Pacific and Mediterranean waters to be lower than 1%. Similarly, high-performance liquid chromatography analyses of fucoxanthin, the major carotenoid present in Bolidophyceae, indicated that less than 4% of the total chlorophyll a in the picoplanktonic fraction in the equatorial Pacific was due to Bolidophyceae. Consequently, although strains of Bolidophyceae have been isolated from samples collected at several stations, this new class seems to have been a minor component of the natural picoeukaryotic populations in the ecosystems investigated, at least during the periods sampled.

TWO THEILERIA CERVI SSU RRNA GENE SEQUENCE TYPES FOUND IN ISOLATES FROM WHITE-TAILED DEER AND ELK IN NORTH AMERICA

1999 ◽  
Vol 35 (3) ◽  
pp. 458-465 ◽  
Author(s):  
Joon-seok Chae ◽  
Suryakant D. Waghela ◽  
Thomas M. Craig ◽  
Alan A. Kocan ◽  
Gerald G. Wagner ◽  
...  
Keyword(s):  
North America ◽  
Gene Sequence ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Rrna Gene Sequence ◽  
Ssu Rrna Gene ◽  
Ssu Rrna Gene Sequence ◽  
Sequence Types

scholarly journals “Cryptic” group-I introns in the nuclear SSU-rRNA gene of Verticillium dahliae

2013 ◽  
Vol 60 (3) ◽  
pp. 135-148 ◽  
Author(s):  
Ioannis A. Papaioannou ◽  
Chrysoula D. Dimopoulou ◽  
Milton A. Typas
Keyword(s):  
Verticillium Dahliae ◽  
Rrna Gene ◽  
Group I Introns ◽  
Ssu Rrna ◽  
Ssu Rrna Gene ◽  
Group I

Redescription and SSU rRNA gene-based phylogeny of an anaerobic ciliate, Plagiopyla ovata Kahl, 1931 (Ciliophora, Plagiopylea)

2021 ◽  
Vol 71 (8) ◽  
Author(s):  
Ran Li ◽  
Wenbao Zhuang ◽  
Congcong Wang ◽  
Hamed El-Serehy ◽  
Saleh A. Al-Farraj ◽  
...  
Keyword(s):  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Small Subunit ◽  
The Yellow Sea ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Gene Trees ◽  
Ssu Rrna Gene ◽  
Anaerobic Ciliate ◽  
Pr China

The morphology and molecular phylogeny of Plagiopyla ovata Kahl, 1931, a poorly known anaerobic ciliate, were investigated based on a population isolated from sand samples collected from the Yellow Sea coast at Qingdao, PR China. Details of the oral ciliature are documented for the first time to our knowledge and an improved species diagnosis is given. The small subunit ribosomal RNA (SSU rRNA) gene was newly sequenced and phylogenetic analyses revealed that P. ovata clusters within the monophyletic family Plagiopylidae. However, evolutionary relationships within both the family Plagiopylidae and the genus Plagiopyla remain obscure owing to undersampling, the lack of sequence data from known species and low nodal support or unstable topologies in gene trees. A key to the identification of the species of the genus Plagiopyla with validly published names is also supplied.

scholarly journals New Intranuclear Symbiotic Bacteria from Macronucleus of Paramecium putrinum—“Candidatus Gortzia Yakutica”

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 198 ◽  
Author(s):  
Alexandra Y. Beliavskaia ◽  
Alexander V. Predeus ◽  
Sofya K. Garushyants ◽  
Maria D. Logacheva ◽  
Jun Gong ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Life Cycle ◽  
Host Species ◽  
Novel Species ◽  
Symbiotic Bacteria ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Ssu Rrna Gene ◽  
Obligate Intracellular

Holospora-like bacteria (HLB) are obligate intracellular Alphaproteobacteria, inhabiting nuclei of Paramecium and other ciliates such as “Candidatus Hafkinia” is in Frontonia. The HLB clade is comprised of four genera, Holospora, Preeria, “Candidatus Gortzia”, and “Candidatus Hafkinia”. These bacteria have a peculiar life cycle with two morphological forms and some degree of specificity to the host species and the type of nucleus they inhabit. Here we describe a novel species of HLB—“Candidatus Gortzia yakutica” sp. nov.—a symbiont from the macronucleus of Paramecium putrinum, the first described HLB for this Paramecium species. The new endosymbiont shows morphological similarities with other HLB. The phylogenetic analysis of the SSU rRNA gene places it into the “Candidatus Gortzia” clade.

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