- Volume 58, Issue 12, 2008
Volume 58, Issue 12, 2008
- New Taxa
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- Other Gram-Positive Bacteria
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Pediococcus argentinicus sp. nov. from Argentinean fermented wheat flour and identification of Pediococcus species by pheS, rpoA and atpA sequence analysis
A Gram-positive, small coccus-shaped lactic acid bacterium, strain LMG 23999T, was isolated from Argentinean wheat flour. 16S rRNA gene sequence analysis revealed that the phylogenetic position of the novel strain was within the genus Pediococcus, with Pediococcus stilesii, Pediococcus pentosaceus and Pediococcus acidilactici as its closest relatives (97.7, 97.3 and 96.9 % gene sequence similarity, respectively). Fluorescent amplified fragment length polymorphism fingerprinting of whole genomes and whole-cell protein electrophoresis confirmed the unique taxonomic status of the novel strain. DNA–DNA hybridizations, DNA G+C content determination, comparative sequence analysis of the pheS, rpoA and atpA genes and physiological and biochemical characterization demonstrated that strain LMG 23999T (=CCUG 54535T=CRL 776T) represents a novel species for which the name Pediococcus argentinicus sp. nov. is proposed. Multi-locus sequence analysis based on pheS, rpoA and atpA genes was found to be a suitable method for the identification of species of the genus Pediococcus.
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Ammonifex thiophilus sp. nov., a hyperthermophilic anaerobic bacterium from a Kamchatka hot spring
A novel anaerobic, extremely thermophilic, facultatively chemolithoautotrophic bacterium designated strain SRT was isolated from a terrestrial hot spring in Kamchatka (Russia). The cells of the novel strain were spore-forming rods with a Gram-positive type of cell wall. The novel isolate grew at 60–82 °C (optimum 75 °C) and pH 6.0–7.5 (optimum 6.8). Molecular hydrogen and formate were used as electron donors. Thiosulfate, sulfate or elemental sulfur served as electron acceptors yielding hydrogen sulfide. No growth was observed on either substrate in the presence of nitrate as the electron acceptor. The G+C content of the DNA was 56.2 mol%. Phylogenetic analyses of the 16S rRNA gene showed that strain SRT was most closely related to Ammonifex degensii (96.4 % gene sequence similarity). However, the novel isolate possessed phenotypic characteristics that differed significantly from those of A. degensii, the only other recognized species of the genus Ammonifex. It is concluded that strain SRT (=DSM 19636T=VKM B-2461T) represents the type strain of a novel species of the genus Ammonifex, for which the name Ammonifex thiophilus sp. nov. is proposed. An emendation of the genus Ammonifex is proposed based on the phenotypic characteristics of the novel species.
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Nosocomiicoccus ampullae gen. nov., sp. nov., isolated from the surface of bottles of saline solution used in wound cleansing
Strains TRF-1T and TC-9 were isolated from transfer spikes of two separate bottles containing 0.9 % NaCl (physiological saline) solution used repeatedly to wash wounds in hospital wards, months apart. Phylogenetic analysis of 16S rRNA gene sequences revealed that strains TRF-1T and TC-9 formed a distinct branch within the family Bacillaceae most closely related to the members of the genus Jeotgalicoccus. The two strains, with identical 16S rRNA gene sequences, showed sequence similarities of 89.8–93.9 % with species of Jeotgalicoccus, 91.1–91.8 % with species of Salinicoccus and 89.1–89.7 % with species of Staphylococcus. Strains TRF-1T and TC-9 are Gram-positive, non-spore-forming and non-motile cocci, with an optimum growth temperature of about 37 °C. Strain TRF-1T grew optimally in medium containing 3 % (w/v) NaCl (maximum about 14 % NaCl), while strain TC-9 grew optimally in medium with 1 % (w/v) NaCl. Both strains produce a brown pigment when grown in the presence of NaCl. The cell-wall peptidoglycan is of the A3α type with a cross-linkage containing the peptide l-Lys–Gly4–l-Ser–Gly. The major respiratory quinones are menaquinone 7 (MK-7) and menaquinone 8 (MK-8), the major fatty acids are straight-chain C14 : 0 and C16 : 0 (more than 85 % of the total) and the major polar lipid is an unknown aminophospholipid. The DNA G+C content is 33.5 mol%. On the basis of the phylogenetic analysis and physiological and biochemical characteristics, we are of the opinion that strains TRF-1T and TC-9 represent a novel species of a new genus, for which we propose the name Nosocomiicoccus ampullae gen. nov., sp. nov. The type strain of Nosocomiicoccus ampullae is strain TRF-1T (=LMG 24060T =CIP 109506T).
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- Evolution, Phylogeny And Biodiversity
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dnaJ is a useful phylogenetic marker for alphaproteobacteria
More LessIn the past, bacterial phylogeny relied almost exclusively on 16S rRNA gene sequence analysis. More recently, multilocus sequence analysis has been used to infer organismal phylogenies. In this study, the dnaJ chaperone gene was investigated as a marker for phylogeny studies in alphaproteobacteria. Preliminary analysis of G+C contents and G+C3s contents (the G+C content of the synonymous third codon position) showed no clear evidence of horizontal transfer of this gene in proteobacteria. dnaJ-based phylogenies were then analysed at three taxonomic levels: the Proteobacteria, the Alphaproteobacteria and the genus Mesorhizobium. Dendrograms based on DnaJ and 16S rRNA gene sequences revealed the same topology described previously for the Proteobacteria. These results indicate that the DnaJ phylogenetic signal is able to reproduce the accepted relationships among the five classes of the Proteobacteria. At a lower taxonomic level, using 20 alphaproteobacteria, the 16S rRNA gene-based phylogeny is distinct from the one based on DnaJ sequence analysis. Although the same clusters are generated, only the topology of the DnaJ tree is consistent with broader phylogenies from recent studies based on concatenated alignments of multiple core genes. For example, the DnaJ tree shows the two clusters within the Rhizobiales as closely related, as expected, while the 16S rRNA gene-based phylogeny shows them as distantly related. In order to evaluate the phylogenetic performance of dnaJ at the genus level, a multilocus analysis based on five housekeeping genes (atpD, gapA, gyrB, recA and rplB) was performed for ten Mesorhizobium species. In contrast to the 16S rRNA gene, the DnaJ sequence analysis generated a tree similar to the multilocus dendrogram. For identification of chickpea mesorhizobium isolates, a dnaJ nucleotide sequence-based tree was used. Despite different topologies, 16S rRNA gene- and dnaJ-based trees led to the same species identification. This study suggests that the dnaJ gene is a good phylogenetic marker, particularly for the class Alphaproteobacteria, since its phylogeny is consistent with phylogenies based on multilocus approaches.
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Lactobacillus phylogenomics – towards a reclassification of the genus
More LessThe extremely diverse genus Lactobacillus is the largest among the lactic acid bacteria, with over 145 recognized species. In this work, which to our knowledge is the largest comparative phylogenomics study of a single genus to date, 12 genomes of Lactobacillus strains were subjected to an array of whole-genome and single-marker phylogenetic approaches, to investigate the case for extracting subgeneric groups and to determine whether a single congruent phylogeny could be identified. We conclude that GroEL is a more robust single-gene phylogenetic marker for the genus Lactobacillus than the 16S rRNA gene, when no whole-genome information is available. Significant incongruence was found, both within a set of trees based on 141 core proteins and within those phylogenies based on numbers of orthologues, concatenated RNA polymerase subunits and single gene/protein markers. This is possibly due to different evolutionary rates, hidden paralogies or horizontal gene transfer. Such phylogenetic ambiguities are efficiently visualized with cluster-networks. Although the genus contains some highly unstable taxa, four subgeneric groups were distinguished. Qualitative and quantitative gene analysis of these groups resulted in three findings: there is a relatively small number of group-specific proteins, the majority of which are poorly characterized; major groupings are functionally better distinguishable by absent genes rather than gained/retained genes; and, finally, a gene cluster possibly involved in purine metabolism is uniquely present in four lactobacilli associated with meat. In conclusion, because of either significantly different branching patterns or the availability of too few members, three of the four identified groups could not serve as the basis for identifying candidate novel genera within the current genus. We therefore suggest targeted sequencing of key taxonomic species identified here, which are likely to add sufficient depth for a future reclassification, followed by phylogenomic analysis involving the core proteins identified here. This will ideally be combined with phenotypic data using a polyphasic approach.
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Systematic position of Discocephalus-like ciliates (Ciliophora: Spirotrichea) inferred from SSU rDNA and ontogenetic information
The Prodiscocephalus-like ciliates, or discocephalines, are cephalized organisms that are traditionally considered to be hypotrichs (sensu lato) but whose precise systematic position has long been uncertain. The main reasons for this are that these organisms exhibit several intermediate morphological and morphogenetic features and that hitherto none has been investigated using molecular methods. In the present study, the cortical development of Prodiscocephalus borrori was observed during binary division and this can be summarized as follows: (i) in the parental adoral zone of membranelles, only the posterior end is renewed by dedifferentiation of the old structures; (ii) the oral primordium in the opisthe occurs de novo on the cell surface as seen in other typical stichotrichs; (iii) in both dividers, the undulating membranes anlage does not split longitudinally in the usual way but, instead, divides transversely to form the paroral and endoral membranes; (iv) usually seven frontoventral transverse cirral anlagen are formed in the primary mode which then divide into two sets, one each for the proter and opisthe; (v) both left and right marginal rows divide into two parts, thus giving rise to a post-lateral marginal segment at the posterior end of each; (vi) invariably five caudal cirri are formed at the posterior end of the three rightmost dorsal kinety anlagen. Thus, it was found that, like other related discocephalines, P. borrori exhibits more similarities to stichotrichs than to euplotids. Based on a combination of morphological and morphogenetic data, a phylogenetic tree was constructed which suggests that the discocephalines group within the stichotrichs and separate from the euplotids. In addition, the complete small-subunit rRNA gene (SSU rDNA) of P. borrori was sequenced and analysed. In the resulting SSU rDNA tree, the discocephalines represent an intermediate group between the euplotids and the Stichotrichia–Oligotrichia–Choreotrichia assemblage, albeit with low bootstrap support. From these data, we conclude that the discocephalines might be a divergent, or possibly an ancestral, group within the Stichotrichia. Furthermore, our findings further support the suggestion that these organisms should be considered as a distinct order, i.e. Discocephalida Wicklow, 1982, in the subclass Stichotrichia Small & Lynn, 1985 .
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- International Committee On Systematics Of Prokaryotes
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- Minutes
- Request For Opinion
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Replacement of ATCC 25944T, the current type strain of Melittangium lichenicola, with ATCC 25946. Request for an Opinion
More LessIt is proposed that the type strain of Melittangium lichenicola (Thaxter 1892) McCurdy 1971 is ATCC 25946 (=DSM 14877), which was originally designated as a reference strain by McCurdy, and not ATCC 25944T, as given in the Approved Lists. Swarm appearance, myxospore morphology and 16S rRNA gene sequence data suggest that ATCC 25946 is a representative of the species Melittangium lichenicola, while strain ATCC 25944 is clearly a member of the Myxococcus–Corallococcus clade. A Request for an Opinion to this effect is made to the Judicial Commission of the International Committee on Systematics of Prokaryotes.
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Volumes and issues
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Volume 74 (2024)
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Volume 73 (2023)
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Volume 72 (2022 - 2023)
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Volume 71 (2020 - 2021)
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Volume 70 (2020)
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Volume 69 (2019)
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Volume 68 (2018)
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Volume 67 (2017)
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Volume 66 (2016)
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Volume 65 (2015)
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Volume 64 (2014)
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Volume 63 (2013)
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Volume 62 (2012)
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Volume 61 (2011)
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Volume 60 (2010)
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Volume 59 (2009)
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Volume 58 (2008)
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Volume 57 (2007)
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Volume 56 (2006)
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Volume 55 (2005)
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Volume 54 (2004)
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Volume 53 (2003)
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Volume 52 (2002)
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Volume 51 (2001)
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Volume 50 (2000)
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Volume 49 (1999)
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Volume 48 (1998)
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Volume 47 (1997)
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Volume 46 (1996)
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Volume 45 (1995)
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Volume 44 (1994)
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Volume 43 (1993)
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Volume 42 (1992)
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Volume 41 (1991)
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Volume 40 (1990)
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Volume 39 (1989)
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Volume 35 (1985)
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Volume 34 (1984)
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Volume 33 (1983)
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Volume 32 (1982)
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Volume 31 (1981)
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Volume 30 (1980)
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Volume 29 (1979)
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Volume 28 (1978)
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Volume 27 (1977)
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Volume 26 (1976)
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Volume 25 (1975)
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Volume 24 (1974)
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Volume 23 (1973)
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Volume 22 (1972)
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Volume 21 (1971)
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Volume 20 (1970)
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Volume 19 (1969)
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Volume 18 (1968)
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Volume 17 (1967)
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Volume 16 (1966)
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Volume 15 (1965)
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Volume 14 (1964)
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Volume 13 (1963)
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Volume 12 (1962)
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Volume 11 (1961)
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Volume 10 (1960)
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Volume 9 (1959)
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Volume 8 (1958)
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Volume 7 (1957)
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Volume 6 (1956)
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Volume 5 (1955)
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Volume 4 (1954)
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Volume 3 (1953)
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Volume 2 (1952)
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Volume 1 (1951)