scholarly journals Bacterial Diversity Profiling around the Orca Seamount in the Bransfield Strait, Antarctica, Based on 16S rRNA Gene Amplicon Sequences

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Wilbert Serrano ◽  
Raul M. Olaechea ◽  
Luis Cerpa ◽  
Jose Herrera ◽  
Aldo Indacochea

ABSTRACT Hydrothermal vent activity is often associated with submarine volcanism. Here, we investigated the presence of microorganisms related to hydrothermal activity in the Orca seamount. Data profiling of the 16S rRNA gene amplicon sequences revealed a diversity pattern dominated mainly by the phyla Proteobacteria, Acidobacteria, Planctomycetes, and Bacteroidetes.

2012 ◽  
Vol 23 (4) ◽  
pp. 409-416 ◽  
Author(s):  
Juliana Vianna Pereira ◽  
Luciana Leomil ◽  
Fabíola Rodrigues-Albuquerque ◽  
José Odair Pereira ◽  
Spartaco Astolfi-Filho

The objective of the present study was to evaluate the bacterial diversity in the saliva of patients with different oral hygiene indexes using of two 16S rRNA gene libraries. Each library was composed of samples from patients with different averages of the differentiated Silness-Löe biofilm index: the first library (A) with an index between 1.0 and 3.0 (considered a high index) and the second library (B) between 0 and 0.5 (considered a low index). Saliva DNA was extracted and the 16S rRNA gene was amplified and cloned. The obtained sequences were compared with those stored at NCBI and RDP GenBank. The saliva of patients with high index presented five known genera - Streptococcus, Granulicatella, Gemella, Veillonella and Peptostreptococcus - and 33.3% of nonculturable bacteria grouped into 23 operational taxonomic units (OTUs). The saliva of patients with low index differed significantly from the first library (p=0.000) and was composed of 42 OTUs distributed into 11 known genera - Streptococcus, Granulicatella, Gemella, Veillonella, Oribacterium, Haemophilus, Escherichia, Neisseria, Prevotella, Capnocytophaga, Actinomyces - including 24.87% of nonculturable bacteria. It was possible to conclude that there is greater bacterial diversity in the saliva of patients with low dental plaque in relation to patients with high dental plaque.


2018 ◽  
Vol 81 (5) ◽  
pp. 848-859
Author(s):  
MIYO NAKANO

ABSTRACT High-throughput sequencing of the 16S rRNA gene enhances understanding of microbial diversity from complex environmental samples. The 16S rRNA gene is currently the most important target in bacterial evolution and ecology studies, particularly for determination of phylogenetic relationships among taxa, exploration of bacterial diversity in a given environment, and quantification of the relative abundance of taxa at various levels. However, some parts of the conserved region of the bacterial 16S rRNA gene are similar to the conserved regions of plant chloroplasts and eukaryotic mitochondria. Therefore, if DNA contains a large amount of nontarget DNA, this nontarget DNA can be coamplified and consequently produce useless sequence reads. We experimentally assessed the primer pair 335f/769r and the widely used bacterial primer pair SD (S-D-Bact-0341-b-S-17/S-D-Bact-0785-a-A-21). The primer pair 335f/769r was examined for its ability to amplify bacterial DNA in plant and animal feed samples by using the single-strand confirmation polymorphism method. In our present study, these primer pairs were validated for microbial community structure analysis with complex food matrices by using next-generation sequencing. The sequencing results revealed that the primer pair 335f/769r successfully resulted in fewer chloroplast and mitochondrial sequence reads than generated by the universal primer pair SD and therefore is comparatively suitable for metagenomic analyses of complex food matrices, particularly those that are rich in plant DNA. Additionally, some taxonomic groups were missed entirely when only the SD primer pair was used.


Author(s):  
Yurina Hashimoto ◽  
Akihiro Tame ◽  
Shigeki Sawayama ◽  
Junichi Miyazaki ◽  
Ken Takai ◽  
...  

A novel mesophilic, strictly anaerobic, chemolithoautotrophic sulphate-reducing bacterium, designated strain KT2T, was isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the Izu-Bonin Arc. Strain KT2T grew at 25–40 °C (optimum 35 °C) and pH 5.5–7.0 (optimum 6.6) in the presence of 25–45 g l−1 NaCl (optimum 30 g l−1). Growth occurred with molecular hydrogen as the electron donor and sulphate, thiosulphate, and sulphite as the electron acceptors. The isolate utilized CO2 as the sole carbon source for chemolithoautotrophic growth on H2. Glycerol, succinate, fumarate, malate, glutamate, or casamino acids could serve as an alternative electron donor in the presence of CO2. Malate, citrate, glutamate, and casamino acids were used as fermentative substrates for weak growth. The G+C content of genomic DNA was 46.1 %. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain KT2T is a member of the family Desulfobulbaceae , showing a sequence similarity of 94.3 % with Desulforhopalus singaporensis . Phylogenomic analysis based on concatenated 156 single-copy marker genes confirmed the same topology as the 16S rRNA gene phylogeny. The ANI and AAI values between strain KT2T and related genera of the family Desulfobulbaceae were 65.6–68.6 % and 53.1–62.9 %. Based on the genomic, molecular, and physiological characteristics, strain KT2T represents a novel genus and species within the family Desulfobulbaceae , for which the name Desulfomarina profundi gen. nov., sp. nov. is proposed, with KT2T (=JCM 34118T = DSM 111364T) as the type strain.


2019 ◽  
Vol 32 (4) ◽  
pp. 248-260 ◽  
Author(s):  
Raphael Barbetta-de-Jesus ◽  
Yury T Granja-Salcedo ◽  
Juliana D Messana ◽  
Luciano Takeshi-Kishi ◽  
Eliana Gertrudes Macedo-Lemos ◽  
...  

Background: Rumen microorganisms have developed a series of complex interactions, representing one of the best examples of symbiosis between microorganisms in nature. Conventional taxonomic methods based on culture techniques are being replaced by molecular techniques that are faster and more accurate. Objective: To characterize rumen bacterial diversity of Nellore steers grazing on tropical pastures by sequencing the 16S rRNA gene using Illumina sequenctng. Methods: Three rumen-cannulated Nellore steers were used. The liquid and solid fractions of the rumen contents were processed to extract metagenomic DNA, and the VI and V2 hypervariable regions of the 16S rRNA gene were sequenced using Illumina sequencing. Results: A total of 11,407,000 reads of adequate quality were generated, and 812 operational taxonomic units (OTUs) were found at the species level. Twenty-seven phyla were identified, and the predominant phyla were Firmicutes (23%), Bacteroidetes (14%), Proteobacteria (10%), Spirochaetes (9%), Fibrobacteres (7%), Tenericutes (5%), and Actinobacteria (2%), which represented 70% of the total phyla identified in the rumen content. Conclusion: Rumen environment in grazing Nellore steers showed high bacterial diversity, with Firmicutes, Bacteroidetes, Proteobacteria, Spirochaetes, and Fibrobacteres as the predominant phyla.


2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 781-786 ◽  
Author(s):  
Maximo Sánchez ◽  
Martha-Helena Ramírez-Bahena ◽  
Alvaro Peix ◽  
María J. Lorite ◽  
Juan Sanjuán ◽  
...  

Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium . The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium , for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T).


2011 ◽  
Vol 225 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Toshinori Kawanami ◽  
Kazuhiro Yatera ◽  
Kazumasa Fukuda ◽  
Kei Yamasaki ◽  
Masamizu Kunimoto ◽  
...  

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