Evolution of Protein Molecules

Manual for the Identification of Medical Bacteria.

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in the nomenclature of prokaryotes. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.

List of new names and new combinations previously effectively, but not validly, published.

The application of phylogenetic taxonomic procedures led to improvements in the classification of bacteria assigned to the phylum Actinobacteria but even so there remains a need to further clarify relationships within a taxon that encompasses organisms of agricultural, biotechnological, clinical, and ecological importance. Classification of the morphologically diverse bacteria belonging to this large phylum based on a limited number of features has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees. Here, draft genome sequences of a large collection of actinobacterial type strains were used to infer phylogenetic trees from genome-scale data using principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families, and genera, as well as many species and a few subspecies were shown to be in need of revision leading to proposals for the recognition of 2 orders, 10 families, and 17 genera, as well as the transfer of over 100 species to other genera. In addition, emended descriptions are given for many species mainly involving the addition of data on genome size and DNA G+C content, the former can be considered to be a valuable taxonomic marker in actinobacterial systematics. Many of the incongruities detected when the results of the present study were compared with existing classifications had been recognized from 16S rRNA gene trees though whole-genome phylogenies proved to be much better resolved. The few significant incongruities found between 16S/23S rRNA and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences. Similarly good congruence was found between the discontinuous distribution of phenotypic properties and taxa delineated in the phylogenetic trees though diverse non-monophyletic taxa appeared to be based on the use of plesiomorphic character states as diagnostic features.

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Genome-Based Taxonomic Classification of the Phylum Actinobacteria

DNA base composition was determined by reversed-phase high-performance liquid chromatography (HPLC). DNA was hydrolysed into nucleosides with nuclease P1 and bacterial alkaline phosphatase. The mixture of nucleosides was applied to HPLC without any further purification. One determination by chromatography needed 2 μg of hydrolysed nucleosides and took only 8 min. The relative standard error of nucleoside analysis was less than 1%. The system described here gives a direct and precise method for determining DNA base composition.

Research letterDetermination of DNA base composition by reversed-phase high-performance liquid chromatography

A Gram-stain-negative, strictly aerobic, non-flagellated, gliding, rod-shaped bacterium, designated C1T was isolated from the coastal sediment of Xiaoshi Island, Weihai, China. Phylogenetic analysis of the 16S rRNA gene and the genome sequence of the newly isolated strain revealed that it belonged to the genus Psychroflexus within the family Flavobacteriaceae. The 16S rRNA gene sequence similarities between strain C1T and the type strains of Psychroflexus members ranged from 91.6 to 94.9%. The AAI, POCP, ANI and dDDH values between strain C1T and Psychroflexus torquis ATCC 700755T were 67.0%, 53.1%, 70.5% and 20.2%, respectively. The DNA G+C content was 34.0 mol%. Strain C1T grows optimally at 28–30 ℃, at pH 7.5–8.0 and with 3.0–5.0% (w/v) NaCl, and its colonies were orange-colored, convex and circular on the MA plate. Positive for hydrolysis of Tween 20 and catalase activities. The dominant respiratory quinone was menaquinone-6, and the major fatty acids were iso-C17:0 3-OH and iso-C15:0. The polar lipids of strain C1T consisted of phosphatidylethanolamine and three unidentified lipids. On the basis of phylogenetic, phenotypic and chemotaxonomic data, it is considered that strain C1T represents a novel species within the genus Psychroflexus, for which, the name Psychroflexus maritimus sp. nov., is proposed. The type strain is C1T (= MCCC 1H00415T = KCTC 72796T).

Psychroflexus maritimus sp. nov., isolated from coastal sediment.

A Gram-stain-negative, aerobic, non-motile, yellow-pigmented rod-shaped and alginate-degrading bacterium, designated B1N29T, was isolated from the gut of the abalone Haliotis rubra obtained in Weihai, China. Strain B1N29T was found to grow at 4–35 ℃ (optimum, 25 ℃), at pH 6.5–9.0 (optimum, 7.0–7.5) and in the presence of 0.5–9% (w/v) NaCl (optimum, 2%). Cells were positive for oxidase and catalase activity. The 16S rRNA-based phylogenetic analysis revealed that the nearest phylogenetic neighbors of strain B1N29T were Tamlana carrageenivorans KCTC 62451T (98.2%) and Tamlana agarivorans KCTC 22176T (97.7%). Based on the phylogenomic analysis, the average nucleotide identity (ANI) values between strain B1N29T and the neighbor strains were 79.2 and 79.0%, respectively; the digital DNA–DNA hybridization (dDDH) values between strain B1N29T and its two closest neighbors were 22.8 and 23.0%, respectively. Menaquinone-6 (MK-6) was detected as the sole respiratory quinone. The dominant cellular fatty acids were iso-C15:0, iso-C17:0 3-OH, anteiso-C15:0 and iso-C15:1 G. The polar lipids included phosphatidylethanolamine, one aminophospholipid, seven aminolipids and five unidentified lipids. Based on the phylogenetic and phenotypic characteristics, strain B1N29T is considered to represent a novel species of the genus Tamlana, for which the name Tamlana haliotis sp. nov. is proposed. The type strain is B1N29T (= KCTC 72683T = MCCC 1H00394T).

Tamlana haliotis sp. nov., isolated from the gut of the abalone Haliotis rubra.

What do we mean by viability in terms of ‘viable but non-culturable’ cells?

An aerobic, Gram-stain negative, rod-shaped, non-motile bacterium, designated as strain HQA918T, was isolated from an ascidian, Botryllus schlosseri, which was collected from the coast of Weihai in the north of the Yellow Sea, in China. The strain grew optimally at 28-30 °C, at pH values 7.0-8.0, and in the presence of 1.0-3.0% (w/v) sodium chloride (NaCl). A phylogenetic analysis based on 16S rRNA gene sequences showed that strain HQA918T can be affiliated with the family Flavobacteriaceae in the phylum Bacteroidetes, with 92.7% similarity to its close relatives. The major fatty acids identified were iso-C15:0, iso-C15:0 3-OH, and summed feature 3 (iso-C15:0 2-OH and/or C16:1ω7c). The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, and five unidentified polar lipids. The G+C content of the genomic DNA was 44.1 mol%. On the basis of the phylogenetic, genotypic, phenotypic, and chemotaxonomic data, this organism should be classified as a representative of a novel genus, for which the name Ascidiaceibacter gen. nov. is proposed. The type species is Ascidiaceibacter salegens sp. nov. (type strain HQA918T = KCTC 52719T = MCCC 1K03259T).

Ascidiaceibacter salegens gen. nov., sp. nov., isolated from an ascidian

A Gram-stain-negative, facultative anaerobic, red-coloured, rod-shaped, non-flagellated, non-motile and non-gliding bacterium, designated strain Z0201T, was isolated from lake water in Yunnan, China (26° 16′ N, 99° 94′ E). Cells of strain Z0201T were 0.2–0.4 µm wide and 1.4–2.5 µm long, catalase-positive and oxidase-negative. Strain Z0201T was found to grow at 4–37 °C (optimum, 30 °C) and pH 6.5–8.5 (pH 7.5) in the presence of 0–2.0 % (w/v) NaCl (0–0.5 %). The sole respiratory quinone of strain Z0201T was MK-7 and the DNA G+C content was 41.2 mol%. The major fatty acid was iso-C15 : 0 (49.4 %). The polar lipid profile of strain Z0201T consisted of aminophospholipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, two unidentified phospholipids and five unidentified lipids. Based on the 16S rRNA gene sequence analysis, strain Z0201T was a member of the genus 
Aquiflexum
, appearing to be closely related to 
Aquiflexum balticum
(95.4 %). On the basis of phenotypic distinctiveness and phylogenetic divergence, strain Z0201T is considered to represent a novel species of the genus 
Aquiflexum
, for which the name 
Aquiflexum
aquatile sp. nov. is proposed. The type strain is Z0201T (=KCTC 62450T=MCCC 1H00328T).

Zong-Jun Du

Papers

Psychroflexus maritimus sp. nov., isolated from coastal sediment.

Tamlana haliotis sp. nov., isolated from the gut of the abalone Haliotis rubra.

What do we mean by viability in terms of ‘viable but non-culturable’ cells?

Ascidiaceibacter salegens gen. nov., sp. nov., isolated from an ascidian

Aquiflexum aquatile sp. nov., isolated from lake water.