scholarly journals Identification and classification of the genus Bacteroides by multilocus sequence analysis

Microbiology ◽  
2011 ◽  
Vol 157 (12) ◽  
pp. 3388-3397 ◽  
Author(s):  
Mitsuo Sakamoto ◽  
Moriya Ohkuma

Multilocus sequence analysis (MLSA) was performed on representative species of the genus Bacteroides. Internal fragments of the genes selected, dnaJ, gyrB, hsp60, recA, rpoB and 16S rRNA, were amplified by direct PCR and then sequenced from 38 Bacteroides strains representing 35 species. Neighbour-joining (NJ), maximum-likelihood (ML) and maximum-parsimony (MP) phylogenies of the individual genes were compared. The data confirm that the potential for discrimination of Bacteroides species is greater using MLSA of housekeeping genes than 16S rRNA genes. Among the housekeeping genes analysed, gyrB was the most informative, followed by dnaJ. Analyses of concatenated sequences (4816 bp) of all six genes revealed robust phylogenetic relationships among different Bacteroides species when compared with the single-gene trees. The NJ, ML and MP trees were very similar, and almost fully resolved relationships of Bacteroides species were obtained, to our knowledge for the first time. In addition, analysis of a concatenation (2457 bp) of the dnaJ, gyrB and hsp60 genes produced essentially the same result. Ten distinct clades were recognized using the SplitsTree4 program. For the genus Bacteroides, we can define species as a group of strains that share at least 97.5 % gene sequence similarity based on the fragments of five protein-coding housekeeping genes and the 16S rRNA gene. This study demonstrates that MLSA of housekeeping genes is a valuable alternative technique for the identification and classification of species of the genus Bacteroides.

2007 ◽  
Vol 57 (3) ◽  
pp. 489-503 ◽  
Author(s):  
Miet Martens ◽  
Manuel Delaere ◽  
Renata Coopman ◽  
Paul De Vos ◽  
Monique Gillis ◽  
...  

Multilocus sequence analysis (MLSA) was performed on representatives of Ensifer (including species previously assigned to the genus Sinorhizobium) and related taxa. Neighbour-joining (NJ), maximum-parsimony (MP) and maximum-likelihood (ML) phylogenies of dnaK, gltA, glnA, recA, thrC and 16S rRNA genes were compared. The data confirm that the potential for discrimination of Ensifer species is greater using MLSA of housekeeping genes than 16S rRNA genes. In incongruence-length difference tests, the 16S rRNA gene was found to be significantly incongruent with the other genes, indicating that this gene should not be used as a single indicator of relatedness in this group. Significant congruence was detected for dnaK, glnA and thrC. Analyses of concatenated sequences of dnaK, glnA and thrC genes yielded very similar NJ, MP and ML trees, with high bootstrap support. In addition, analysis of a concatenation of all six genes essentially produced the same result, levelling out potentially conflicting phylogenetic signals. This new evidence supports the proposal to unite Ensifer and Sinorhizobium in a single genus. Support for an alternative solution preserving the two genera is less strong. In view of the opinions expressed by the Judicial Commission, the name of the genus should be Ensifer, as proposed by Young [Young, J. M. (2003). Int J Syst Evol Microbiol 53, 2107–2110]. Data obtained previously and these new data indicate that Ensifer adhaerens and ‘Sinorhizobium morelense’ are not heterotypic synonyms, but represent separate species. However, transfer to the genus Ensifer is not possible at present because the species name is the subject of a pending Request for an Opinion, which would affect whether a novel species in the genus Ensifer or a new combination based on a basonym would be created.


2015 ◽  
Vol 65 (Pt_8) ◽  
pp. 2653-2660 ◽  
Author(s):  
Zhi-Ping Zhong ◽  
Ying Liu ◽  
Hong-Can Liu ◽  
Fang Wang ◽  
Yu-Guang Zhou ◽  
...  

A Gram-stain-negative, catalase- and oxidase-positive, facultatively aerobic bacterium, strain DSG-S6T, was isolated from Dasugan Lake (salinity 3.1 %, w/w), China. Its taxonomic position was determined by using a polyphasic approach. Cells of strain DSG-S6T were non-spore-forming, slightly bent rods, and motile by means of a single polar flagellum. Growth occurred in the presence of 0–7.0  % (w/v) NaCl (optimum, 2.0  %), at 4–35 °C (optimum, 30 °C) and at pH 6.0–10.5 (optimum, pH 8.0–8.5). C16 : 0, C18 : 1ω7c and C16 : 1ω7c and/or C16 : 1ω6c were the major fatty acids. Six alleles of the 16S rRNA gene sharing 98.9–99.9  % similarity were detected in strain DSG-S6T, which showed highest 16S rRNA gene sequence similarity to Vibrio aestuarianus ATCC 35048T (97.7  %), then to Vibrio pacinii LMG 19999T (97.6  %) and Vibrio metschnikovii CIP 69.14T (96.8  %). Multilocus sequence analysis of four housekeeping genes and 16S rRNA genes clearly clustered it as a member of the Anguillarum clade. Mean DNA–DNA relatedness between strain DSG-S6T and V. aestuarianus NBRC 15629T, V. pacinii CGMCC 1.12557T and V. metschnikovii JCM 21189T was 20.6 ± 2.3, 38.1 ± 3.5 and 24.2 ± 2.8  %, respectively. The DNA G+C content was 46.8 mol% (T m). Based on the data, it is concluded that strain DSG-S6T represents a novel species of the genus Vibrio, for which the name Vibrio salilacus sp. nov. is proposed. The type strain is DSG-S6T ( = CGMCC 1.12427T = JCM 19265T).


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.


2015 ◽  
Vol 65 (Pt_7) ◽  
pp. 2320-2325 ◽  
Author(s):  
Shih-Yao Lin ◽  
Asif Hameed ◽  
Cheng-Zhe Wen ◽  
You-Cheng Liu ◽  
Yi-Han Hsu ◽  
...  

A Gram-stain-negative, aerobic, rod-shaped, yellow-pigment-producing bacterium (designated strain CC-CZW007T) was isolated from seafood samples (sea urchins) at Penghu Island in Taiwan. Strain CC-CZW007T grew optimally at pH 7.0 and 30 °C in the presence of 3 % (w/v) NaCl. The novel strain shared highest 16S rRNA gene sequence similarity to Vitellibacter vladivostokensis JCM 11732T (96.8 %), Vitellibacter soesokkakensis KCTC 32536T (96.4 %), Vitellibacter nionensis KCTC 32420T (95.8 %) and Vitellibacter aestuarii JCM 15496T (95.6 %) and lower sequence similarity to members of other genera. Phylogenetic analyses based on 16S rRNA genes revealed a distinct taxonomic position attained by strain CC-CZW007T with respect to other species of the genus Vitellibacter. The major fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH. The polar lipid profile was composed of major amounts of phosphatidylethanolamine, unidentified lipids and aminolipids; a moderate amount of aminophospholipid was also detected. The DNA G+C content was 34.7 mol%. The predominant quinone system was menaquinone (MK-6). On the basis of polyphasic taxonomic evidence presented here, strain CC-CZW007T is proposed to represent a novel species within the genus Vitellibacter, for which the name Vitellibacter echinoideorum sp. nov. is proposed. The type strain is CC-CZW007T ( = BCRC 80886T = JCM 30378T).


2005 ◽  
Vol 55 (5) ◽  
pp. 1959-1963 ◽  
Author(s):  
M. J. Pujalte ◽  
M. C. Macián ◽  
D. R. Arahal ◽  
E. Garay

The type strains of Jannaschia cystaugens (LMG 22015T) and Thalassobacter stenotrophicus (CECT 5294T) were analysed by means of genomic DNA–DNA hybridization, comparison of 16S rRNA gene sequences and phenotypic properties determined under the same methodological conditions. J. cystaugens LMG 22015T showed DNA–DNA relatedness levels of 72 % when hybridized with the genomic DNA of T. stenotrophicus CECT 5294T. Sequence comparisons revealed that the 16S rRNA genes of the two strains had a similarity of 99·8 %. The cellular fatty acid and polar lipid compositions of the two strains and their DNA mol% G+C contents were almost identical. Bacteriochlorophyll a (Bchl a) and polyhydroxybutyrate were produced by both strains under the same culture conditions. Their closest phylogenetic neighbours were Jannaschia helgolandensis and Jannaschia rubra; however, the low sequence similarity values (95·7–95·9 %) and several important differences in phenotypic traits (ionic requirements, Bchl a production and polar lipids) support the distinction between the genera Thalassobacter and Jannaschia. Thus, we propose the unification of J. cystaugens (LMG 22015T) and T. stenotrophicus (CECT 5294T) as Thalassobacter stenotrophicus (type strain, CECT 5294T=DSM 16310T). An emended description of the genus Thalassobacter is also presented.


2007 ◽  
Vol 57 (7) ◽  
pp. 1402-1407 ◽  
Author(s):  
M. C. Gutiérrez ◽  
A. M. Castillo ◽  
M. Kamekura ◽  
Y. Xue ◽  
Y. Ma ◽  
...  

Strain SH-6T was isolated from the sediment of Lake Shangmatala, a saline lake in Inner Mongolia (China). Cells were pleomorphic. The organism was neutrophilic and required at least 2.5 M (15 %) NaCl, but not MgCl2, for growth; optimal growth occurred at 4.3 M (25 %) NaCl. The G+C content of its DNA was 63.1 mol%. 16S rRNA gene sequence analysis revealed that strain SH-6T is a member of the family Halobacteriaceae, but there was a low level of similarity with other members of this family. Highest sequence similarity (94.6 %) was obtained with the 16S rRNA genes of the type strains of Natronolimnobius innermongolicus and Natronolimnobius baerhuensis. Polar lipid analyses revealed that strain SH-6T contains phosphatidylglycerol and phosphatidylglyceromethylphosphate, derived from both C20C20 and C20C25 glycerol diethers together with the glycolipid S2-DGD-1. On the basis of the data obtained, the new isolate could not be classified in any recognized genus. Strain SH-6T is thus considered to represent a novel species in a new genus within the family Halobacteriaceae, order Halobacteriales, for which the name Halopiger xanaduensis gen. nov., sp. nov. is proposed. The type strain of Halopiger xanaduensis is SH-6T (=CECT 7173T=CGMCC 1.6379T=JCM 14033T).


2014 ◽  
Vol 64 (Pt_7) ◽  
pp. 2274-2279 ◽  
Author(s):  
Cheol Su Park ◽  
Kyudong Han ◽  
Tae-Young Ahn

A Gram-staining-negative, strictly aerobic, rod-shaped, pale-pink pigmented bacterial strain, designated TF8T, was isolated from leaf mould in Cheonan, Republic of Korea. Its taxonomic position was determined through a polyphasic approach. Optimal growth occurred on R2A agar without NaCl supplementation, at 25–28 °C and at pH 6.0–7.0. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain TF8T belongs to the genus Mucilaginibacter in the family Sphingobacteriaceae . The sequence similarity between 16S rRNA genes of strain TF8T and the type strains of other species of the genus Mucilaginibacter ranged from 92.1 to 94.7 %. The closest relatives of strain TF8T were Mucilaginibacter lutimaris BR-3T (94.7 %), M. soli R9-65T (94.5 %), M. litoreus BR-18T (94.5 %), M. rigui WPCB133T (94.0 %) and M. daejeonensis Jip 10T (93.8 %). The major isoprenoid quinone was MK-7 and the major cellular fatty acids were iso-C15 : 0 (33.0 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 24.8 %) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 13.0 %). The major polar lipids of TF8T were phosphatidylethanolamine and three unidentified aminophospholipids. The G+C content of the genomic DNA was 46.2 mol%. On the basis of the data presented here, strain TF8T is considered to represent a novel species of the genus Mucilaginibacter , for which the name Mucilaginibacter koreensis sp. nov. is proposed. The type strain is TF8T ( = KACC 17468T = JCM 19323T).


Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 481-496 ◽  
Author(s):  
Isabelle Iteman ◽  
Rosmarie Rippka ◽  
Nicole Tandeau de Marsac ◽  
Michael Herdman

The taxonomic coherence and phylogenetic relationships of 11 planktonic heterocystous cyanobacterial isolates were examined by investigating two areas of the rRNA operon, the 16S rRNA gene (rrnS) and the internal transcribed spacer (ITS) located between the 16S rRNA and 23S rRNA genes. The rrnS sequences were determined for five strains, including representatives of Anabaena flos-aquae, Aphanizomenon flos-aquae, Nodularia sp. and two alkaliphilic planktonic members of the genera Anabaenopsis and Cyanospira, whose phylogenetic position was previously unknown. Comparison of the data with those previously published for individual groups of planktonic heterocystous cyanobacteria showed that, with the exception of members assigned to the genus Cylindrospermopsis, all the planktonic strains form a distinct subclade within the monophyletic clade of heterocystous cyanobacteria. Within this subclade five different phylogenetic clusters were distinguished. The phylogenetic groupings of Anabaena and Aphanizomenon strains within three of these clusters were not always consistent with their generic or specific assignments based on classical morphological definitions, and the high degree of sequence similarity between strains of Anabaenopsis and Cyanospira suggests that they may be assignable to a single genus. Ribotyping and additional studies performed on PCR amplicons of the 16S rDNA or the ITS for the 11 planktonic heterocystous strains demonstrated that they all contain multiple rrn operons and ITS regions of variable size. Finally, evidence is provided for intra-genomic sequence heterogeneity of the 16S rRNA genes within most of the individual isolates.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ingo C. Starke ◽  
Wilfried Vahjen ◽  
Robert Pieper ◽  
Jürgen Zentek

In this study, the effect of different DNA extraction procedures and primer sets on pyrosequencing results regarding the composition of bacterial communities in the ileum of piglets was investigated. Ileal chyme from piglets fed a diet containing different amounts of zinc oxide was used to evaluate a pyrosequencing study with barcoded 16S rRNA PCR products. Two DNA extraction methods (bead beating versus silica gel columns) and two primer sets targeting variable regions of bacterial 16S rRNA genes (8f-534r versus 968f-1401r) were considered. The SEED viewer software of the MG-RAST server was used for automated sequence analysis. A total of 5.2×105 sequences were used for analysis after processing for read length (150 bp), minimum sequence occurrence (5), and exclusion of eukaryotic and unclassified/uncultured sequences. DNA extraction procedures and primer sets differed significantly in total sequence yield. The distribution of bacterial order and main bacterial genera was influenced significantly by both parameters. However, this study has shown that the results of pyrosequencing studies using barcoded PCR amplicons of bacterial 16S rRNA genes depend on DNA extraction and primer choice, as well as on the manner of downstream sequence analysis.


2011 ◽  
Vol 57 (12) ◽  
pp. 975-981 ◽  
Author(s):  
Houda Baati ◽  
Raja Jarboui ◽  
Néji Gharsallah ◽  
Abdelghani Sghir ◽  
Emna Ammar

The microbial community of a magnesium-rich bittern brine saturated with NaCl (380–400 g/L) from a Tunisian solar saltern was investigated using a molecular approach based on 16S rRNA gene analysis and viability tests. The results revealed the existence of microbial flora. Viability test assessment showed that 46.4% of this flora was viable but not detectable by culturability tests. 16S rRNA genes from 49 bacterial clones and 38 archaeal clones were sequenced and phylogenetically analyzed. Eleven operational taxonomic units (OTUs) determined by the DOTUR program with 97% sequence similarity were generated for Bacteria. These OTUs were affiliated with Bacteroidetes and Gammaproteobacteria. The archaeal community composition exhibited more diversity with 38 clones, resulting in 13 OTUs affiliated with the Euryarchaeota phylum. Diversity measurement showed a more diverse archaeal than bacterial community at the saturated pond.


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