scholarly journals Biodiversity and Emerging Biogeography of the Neutrophilic Iron-Oxidizing Zetaproteobacteria

2011 ◽  
Vol 77 (15) ◽  
pp. 5445-5457 ◽  
Author(s):  
Sean M. McAllister ◽  
Richard E. Davis ◽  
Joyce M. McBeth ◽  
Bradley M. Tebo ◽  
David Emerson ◽  
...  

ABSTRACTMembers of the neutrophilic iron-oxidizing candidate classZetaproteobacteriahave predominantly been found at sites of microbially mediated iron oxidation in marine environments around the Pacific Ocean. Eighty-four full-length (>1,400-bp) and 48 partial-lengthZetaproteobacteriasmall-subunit (SSU) rRNA gene sequences from five novel clone libraries, one novelZetaproteobacteriaisolate, and the GenBank database were analyzed to assess the biodiversity of this burgeoning class of theProteobacteriaand to investigate its biogeography between three major sampling regions in the Pacific Ocean: Loihi Seamount, the Southern Mariana Trough, and the Tonga Arc. Sequences were grouped into operational taxonomic units (OTUs) on the basis of a 97% minimum similarity. Of the 28 OTUs detected, 13 were found to be endemic to one of the three main sampling regions and 2 were ubiquitous throughout the Pacific Ocean. Additionally, two deeply rooted OTUs that potentially dominate communities of iron oxidizers originating in the deep subsurface were identified. Spatial autocorrelation analysis and analysis of molecular variance (AMOVA) showed that geographic distance played a significant role in the distribution ofZetaproteobacteriabiodiversity, whereas environmental parameters, such as temperature, pH, or total Fe concentration, did not have a significant effect. These results, detected using the coarse resolution of the SSU rRNA gene, indicate that theZetaproteobacteriahave a strong biogeographic signal.

Author(s):  
Xiupian Liu ◽  
Qiliang Lai ◽  
Fengqin Sun ◽  
Yaping Du ◽  
Yingbao Gai ◽  
...  

A taxonomic study was carried out on strain C16B3T, which was isolated from deep seawater of the Pacific Ocean. The bacterium was Gram-stain-negative, oxidase- and catalase- positive and rod-shaped. Growth was observed at salinities of 0–8.0 % and at temperatures of 10–45 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C16B3T belonged to the genus Solimonas , with the highest sequence similarity to Solimonas terrae KIS83-12T (97.2 %), followed by Solimonas variicoloris MN28T (97.0 %) and the other four species of the genus Solimonas (94.5 –96.8 %). The average nucleotide identity and estimated DNA–DNA hybridization values between strain C16B3T and the type strains of the genus Solimonas were 74.05−79.48 % and 19.5–22.5 %, respectively. The principal fatty acids (>5 %) were summed feature 8 (C18 : 1  ω7c/C18 : 1  ω6c; 20.9 %), iso-C16 : 0 (14.6 %), C16 : 1  ω5c (9.4 %), iso-C12 : 0 (8.4 %), summed feature 2 (C14 : 0 3-OH/iso I-C16 : 1 and C12 : 0 aldehyde; 6.8 %) and C16 : 0 (5.5 %). The G+C content of the chromosomal DNA was 65.37 mol%. The respiratory quinone was determined to be Q-8 (100 %). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unidentified aminolipids, six unidentified phospholipids and one unidentified polar lipid. The combined genotypic and phenotypic data show that strain C16B3T represents a novel species within the genus Solimonas , for which the name Solimonas marina sp. nov. is proposed, with the type strain C16B3T (=MCCC 1A04678T=KCTC 52314T).


2012 ◽  
Vol 78 (11) ◽  
pp. 4051-4056 ◽  
Author(s):  
Lisa D. Tymensen ◽  
Tim A. McAllister

ABSTRACTThe diversity of protozoan-associated methanogens in cattle was investigated using five universal archaeal small-subunit (SSU) rRNA gene primer sets.Methanobrevibacterspp. and rumen cluster C (distantly related toThermoplasmaspp.) were predominant. Significant differences in species composition among libraries indicate that some primers used previously to characterize rumen methanogens exhibit biased amplification.


2014 ◽  
Vol 64 (Pt_8) ◽  
pp. 2512-2516 ◽  
Author(s):  
Jie Pan ◽  
Cong Sun ◽  
Xin-Qi Zhang ◽  
Ying-Yi Huo ◽  
Xu-Fen Zhu ◽  
...  

Strain CMB17T was a short rod-shaped bacterium isolated from marine sediment of the Pacific Ocean. Cells were Gram-stain-negative and non-motile. Optimal growth occurred at 25–30 °C, pH 6.5–7 and 0.5–1 % (w/v) NaCl. The major fatty acid was C18 : 1ω7c (87.59 %), and ubiquinone-10 was detected as the only isoprenoid quinone. The DNA G+C content of the genomic DNA was 62.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CMB17T is most closely related to Paracoccus stylophorae KTW-16T (96.7 %), P. solventivorans DSM 6637T (96.4 %) and P. saliphilus YIM 90738T (96.4 %). Based on phenotypic, genotypic and phylogenetic characteristics, strain CMB17T is proposed to represent a novel species, denominated Paracoccus sediminis sp. nov. (type strain CMB17T = JCM 18467T = DSM 26170T = CGMCC 1.12681T).


2011 ◽  
Vol 77 (10) ◽  
pp. 3234-3243 ◽  
Author(s):  
Tommy Harding ◽  
Anne D. Jungblut ◽  
Connie Lovejoy ◽  
Warwick F. Vincent

ABSTRACTWe applied molecular, microscopic, and culture techniques to characterize the microbial communities in snow and air at remote sites in the Canadian High Arctic (Ward Hunt Island, Ellesmere Island, and Cornwallis Island, latitudes 74 to 83oN). Members of theBacteriaandEukaryawere prevalent in the snow, and their small subunit (SSU) rRNA gene signatures indicated strong local aerial transport within the region over the preceding 8 months of winter snowpack accumulation. Many of the operational taxonomic units (OTUs) were similar to previously reported SSU rRNA gene sequences from the Arctic Ocean, suggesting the importance of local aerial transport processes for marine microbiota. More than 47% of the cyanobacterial OTUs in the snow have been previously found in microbial mats in the region, indicating that this group was also substantially derived from local sources. Viable cyanobacteria isolated from the snow indicated free exchange between the snow and adjacent mat communities. Other sequences were most similar to those found outside the Canadian Arctic but were from snow, lake and sea ice, glaciers and permafrost, alpine regions, Antarctica, and other regions of the Arctic, supporting the concept of global distribution of microbial ecotypes throughout the cold biosphere.


1998 ◽  
Vol 64 (1) ◽  
pp. 294-303 ◽  
Author(s):  
Michael S. Rappé ◽  
Marcelino T. Suzuki ◽  
Kevin L. Vergin ◽  
Stephen J. Giovannoni

ABSTRACT The scope of marine phytoplankton diversity is uncertain in many respects because, like bacteria, these organisms sometimes lack defining morphological characteristics and can be a challenge to grow in culture. Here, we report the recovery of phylogenetically diverse plastid small-subunit (SSU) rRNA gene (rDNA) clones from natural plankton populations collected in the Pacific Ocean off the mouth of Yaquina Bay, Oreg. (OCS clones), and from the eastern continental shelf of the United States off Cape Hatteras, N.C. (OM clones). SSU rRNA gene clone libraries were prepared by amplifying rDNAs from nucleic acids isolated from plankton samples and cloning them into plasmid vectors. The PCR primers used for amplification reactions were designed to be specific for bacterial SSU rRNA genes; however, plastid genes have a common phylogenetic origin with bacteria and were common in both SSU rRNA gene clone libraries. A combination of restriction fragment length polymorphism analyses, nucleic acid sequencing, and taxon-specific oligonucleotide probe hybridizations revealed that 54 of the 116 OCS gene clones were of plastid origin. Collectively, clones from the OCS and OM libraries formed at least eight unique lineages within the plastid radiation, including gene lineages related to the classesBacillariophyceae, Cryptophyceae,Prymnesiophyceae, Chrysophyceae, andPrasinophyceae; for a number of unique clones, no close phylogenetic neighbors could be identified with confidence. Only a group of two OCS rRNA gene clones showed close identity to the plastid SSU rRNA gene sequence of a cultured organism [Emiliania huxleyi (Lohmann) Hay and Mohler; 99.8% similar]. The remaining clones could not be identified to the genus or species level. Although cryptic species are not as prevalent among phytoplankton as they are among their bacterial counterparts, this genetic survey nonetheless uncovered significant new information about phytoplankton diversity.


2018 ◽  
Author(s):  
Jeffrey S. McLean ◽  
Batbileg Bor ◽  
Thao T. To ◽  
Quanhui Liu ◽  
Kristopher A. Kerns ◽  
...  

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.


Author(s):  
Ran Li ◽  
Wenbao Zhuang ◽  
Congcong Wang ◽  
Hamed El-Serehy ◽  
Saleh A. Al-Farraj ◽  
...  

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.


2005 ◽  
Vol 55 (6) ◽  
pp. 2595-2604 ◽  
Author(s):  
Dag Klaveness ◽  
Kamran Shalchian-Tabrizi ◽  
Helge Abildhauge Thomsen ◽  
Wenche Eikrem ◽  
Kjetill S. Jakobsen

Telonema is a widely distributed group of phagotrophic flagellates with two known members. In this study, the structural identity and molecular phylogeny of Telonema antarcticum was investigated and a valid description is proposed. Molecular phylogeny was studied using small-subunit rRNA (SSU rRNA) gene sequences. The pear-shaped cell had two subequal flagella that emerged laterally on the truncated antapical tail. One flagellum had tripartite hairs. The cell was naked, but had subsurface vesicles containing angular paracrystalline bodies of an unknown nature. A unique complex cytoskeletal structure, the subcortical lamina, was found to be an important functional and taxonomic feature of the genus. Telonema has an antero-ventral depression where food particles are ingested and then transferred to a conspicuous anterior food vacuole. The molecular phylogeny inferred from the SSU rRNA gene sequence suggested that Telonema represents an isolated and deep branch among the tubulocristate protists.


mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Harald R. Gruber-Vodicka ◽  
Brandon K. B. Seah ◽  
Elmar Pruesse

ABSTRACT The small-subunit rRNA (SSU rRNA) gene is the key marker in molecular ecology for all domains of life, but it is largely absent from metagenome-assembled genomes that often are the only resource available for environmental microbes. Here, we present phyloFlash, a pipeline to overcome this gap with rapid, SSU rRNA-centered taxonomic classification, targeted assembly, and graph-based binning of full metagenomic assemblies. We show that a cleanup of artifacts is pivotal even with a curated reference database. With such a filtered database, the general-purpose mapper BBmap extracts SSU rRNA reads five times faster than the rRNA-specialized tool SortMeRNA with similar sensitivity and higher selectivity on simulated metagenomes. Reference-based targeted assemblers yielded either highly fragmented assemblies or high levels of chimerism, so we employ the general-purpose genomic assembler SPAdes. Our optimized implementation is independent of reference database composition and has satisfactory levels of chimera formation. phyloFlash quickly processes Illumina (meta)genomic data, is straightforward to use, even as part of high-throughput quality control, and has user-friendly output reports. The software is available at https://github.com/HRGV/phyloFlash (GPL3 license) and is documented with an online manual. IMPORTANCE To track organisms across all domains of life, the SSU rRNA gene is the gold standard. Many environmental microbes are known only from high-throughput sequence data, but the SSU rRNA gene, the key to visualization by molecular probes and link to existing literature, is often missing from metagenome-assembled genomes (MAGs). The easy-to-use phyloFlash software suite tackles this gap with rapid, SSU rRNA-centered taxonomic classification, targeted assembly, and graph-based linking to MAGs. Starting from a cleaned reference database, phyloFlash profiles the taxonomic diversity and assembles the sorted SSU rRNA reads. The phyloFlash design is domain agnostic and covers eukaryotes, archaea, and bacteria alike. phyloFlash also provides utilities to visualize multisample comparisons and to integrate the recovered SSU rRNAs in a metagenomics workflow by linking them to MAGs using assembly graph parsing.


Subject Prospects for agriculture in 2017. Significance The El Nino weather phenomenon, the heating of the Pacific Ocean, experienced through 2015 and 2016 was one of the strongest recorded, causing extreme weather events and decreasing global agriculture production. Next year promises a departure.


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