Against conservation of specific epithets formed wrongly as nominative nouns in apposition.

Together with 31 other incorrectly formed (i.e. as nominative nouns in apposition) specific epithets, the epithet of Streptomyces scabies was corrected to Streptomyces scabiei in Taxonomic Notes published in 1997 and 1998. A subsequent Request for an Opinion, published in 2001, to reinstate the incorrect epithets for ten of these species was denied by the Judicial Commission in 2002. In 2007, a further Request for an Opinion was submitted to the Judicial Commission which proposed the conservation of the incorrect epithet of Streptomyces 'scabies' over the corrected one, scabiei. After having stated once that the corrections made to the epithets were performed according to the correct application of the International Code of Nomenclature of Bacteria (now 'of Prokaryotes', ICNP), the Judicial Commission would lose authority and credibility if it were to follow a request to abandon even one of the now correct 32 epithets in favour of its incorrectly formed predecessor. Microbiologists who accept changes in names of genera should also accept the correction of grammatical or orthographical changes in specific epithets.

Neo-Latinists worldwide willing to help microbiologists.

As knowledge of Latin is no longer widespread in the community of natural scientists, the International Association for Neo-Latinist Studies (IANLS) has been contacted and asked for assistance in Latin (Neo-Latin) name formation for the formal description of newly isolated prokaryotes. Here, the names and addresses of sixteen Neo-Latin scholars and three microbiologists with knowledge of Latin and relevant experience are given, all of whom offer their help. Instructions about the procedure necessary for such consultations are included.

Thiosulphate oxidation in the phototrophic sulphur bacterium Allochromatium vinosum.

Two different pathways for thiosulphate oxidation are present in the purple sulphur bacterium Allochromatium vinosum: oxidation to tetrathionate and complete oxidation to sulphate with obligatory formation of sulphur globules as intermediates. The tetrathionate:sulphate ratio is strongly pH-dependent with tetrathionate formation being preferred under acidic conditions. Thiosulphate dehydrogenase, a constitutively expressed monomeric 30 kDa c-type cytochrome with a pH optimum at pH 4.2 catalyses tetrathionate formation. A periplasmic thiosulphate-oxidizing multienzyme complex (Sox) has been described to be responsible for formation of sulphate from thiosulphate in chemotrophic and phototrophic sulphur oxidizers that do not form sulphur deposits. In the sulphur-storing A. vinosum we identified five sox genes in two independent loci (soxBXA and soxYZ). For SoxA a thiosulphate-dependent induction of expression, above a low constitutive level, was observed. Three sox-encoded proteins were purified: the heterodimeric c-type cytochrome SoxXA, the monomeric SoxB and the heterodimeric SoxYZ. Gene inactivation and complementation experiments proved these proteins to be indispensable for thiosulphate oxidation to sulphate. The intermediary formation of sulphur globules in A. vinosum appears to be related to the lack of soxCD genes, the products of which are proposed to oxidize SoxY-bound sulphane sulphur. In their absence the latter is instead transferred to growing sulphur globules.

Leadbetterella byssophila gen. nov., sp. nov., isolated from cotton-waste composts for the cultivation of oyster mushroom.

A bacterial strain, designated 4M15T, was isolated from cotton-waste composts used as mushroom cultivation in South Korea. Properties of this isolate were studied on the basis of physiological and biochemical characteristics, fatty acid profile, isoprenoid quinone, DNA G+C content and phylogenetic position based on 16S rRNA gene sequence analysis. The strain was found to form a distinct phylogenetic lineage related to the family 'Flexibacteraceae' within the phylum 'Bacteroidetes'. No recognized species showed >85 % 16S rRNA gene sequence similarity to strain 4M15T. The fatty acid profile of strain 4M15(T) included C(16 : 1)omega7c/iso-C(15 : 0) 2-OH (30.5 %), iso-C(15 : 0) (24.2 %), iso-C(15 : 0) 2-OH/C(16 : 1)omega7c (15.9), iso-C(17 : 0) 3-OH (10.5 %) and C(16 : 0) (5.6 %). The major isoprenoid quinone was menaquinone MK-7. The DNA G+C content was 33.0 mol%. Cells were Gram-negative, strictly aerobic, rod-shaped, non-motile, catalase-positive, oxidase-positive and flexirubin-positive. The strain hydrolysed aesculin, gelatin, starch and tyrosine. Several phenotypic tests could be used to differentiate strain 4M15T from other members of the family 'Flexibacteraceae'. On the basis of the data presented, strain 4M15T should be assigned to the phylum 'Bacteroidetes' as a novel genus and species, for which the name Leadbetterella byssophila gen. nov., sp. nov. is proposed. The type strain is 4M15T (=KACC 11308T=DSM 17132T).

The role of the sulfur globule proteins of Allochromatium vinosum: mutagenesis of the sulfur globule protein genes and expression studies by real-time RT-PCR.

During oxidation of reduced sulfur compounds, the purple sulfur bacterium Allochromatium vinosum stores sulfur in the periplasm in the form of intracellular sulfur globules. The sulfur in the globules is enclosed by a protein envelope that consists of the homologous 10.5-kDa proteins SgpA and SgpB and the smaller 8.5-kDa SgpC. Reporter gene fusions of sgpA and alkaline phosphatase showed the constitutive expression of sgpA in A. vinosum and yielded additional evidence for the periplasmic localization of the sulfur globules. Expression analysis of the wild-type sgp genes by quantitative RT-PCR using the LightCycler system showed the constitutive expression of all three sgp genes. The expression of sgpB and sgpC is significantly enhanced under photolithotrophic conditions. Interestingly, sgpB is expressed ten times less than sgpA and sgpC implying that SgpA and SgpC are the "main proteins" of the sulfur globule envelope. Mutants with inactivated sgpA or sgpB did not show any differences in comparison with the wild-type, i.e., the encoded proteins can replace each other, whereas inactivation of sgpC leads to the formation of considerably smaller sulfur globules. This indicates a role of SgpC for globule expansion. A sgpBC double mutant was unable to grow on sulfide and could not form sulfur globules, showing that the protein envelope is indispensible for the formation and deposition of intracellular sulfur.

Report of the ad hoc committee for the re-evaluation of the species definition in bacteriology.

An ad hoc committee for the re-evaluation of the species definition in bacteriology met in Gent, Belgium, in February 2002. The committee made various recommendations regarding the species definition in the light of developments in methodologies available to systematists.

Quantitative speciation of sulfur in bacterial sulfur globules: X-ray absorption spectroscopy reveals at least three different species of sulfur.

X-ray absorption near edge structure (XANES) spectroscopy at the sulfur K-edge was applied to probe the speciation of sulfur of metabolically different sulfur-accumulating bacteria in situ. Fitting the spectra using a least-square fitting routine XANES reveals at least three different forms of sulfur in bacterial sulfur globules. Cyclooctasulfur dominates in the sulfur globules of Beggiatoa alba and the very recently described giant bacterium Thiomargarita namibiensis. A second type of sulfur globules is present in Acidithiobacillus ferrooxidans: here the sulfur occurs as polythionates. In contrast, in purple and green sulfur bacteria the sulfur mainly consists of sulfur chains, irrespective of whether it is accumulated in globules inside or outside the cells. These results indicate that the speciation of sulfur in the sulfur globules reflects the different ecological and physiological properties of different metabolic groups of bacteria.

A dissimilatory sirohaem-sulfite-reductase-type protein from the hyperthermophilic archaeon Pyrobaculum islandicum.

A sulfite-reductase-type protein was purified from the hyperthermophilic crenarchaeote Pyrobaculum islandicum grown chemoorganoheterotrophically with thiosulfate as terminal electron acceptor. In common with dissimilatory sulfite reductases the protein has an alpha 2 beta 2 structure and contains high-spin sirohaem, non-haem iron and acid-labile sulfide. The oxidized protein exhibits absorption maxima at 280, 392, 578 and 710 nm with shoulders at 430 and 610 nm. The isoelectric point of pH 8.4 sets the protein apart from all dissimilatory sulfite reductases characterized thus far. The genes for the alpha- and beta-subunits (dsrA and dsrB) are contiguous in the order dsrAdsrB and most probably comprise an operon with the directly following dsrG and dsrC genes. dsrG and dsrC encode products which are homologous to eukaryotic glutathione S-transferases and the proposed gamma-subunit of Desulfovibrio vulgaris sulfite reductase, respectively. dsrA and dsrB encode 44.2 kDa and 41.2 kDa peptides which show significant similarity to the two homologous subunits DsrA and DsrB of dissimilatory sulfite reductases. Phylogenetic analyses indicate a common protogenotic origin of the P. islandicum protein and the dissimilatory sulfite reductases from sulfate-reducing and sulfide-oxidizing prokaryotes. However, the protein from P. islandicum and the sulfite reductases from sulfate-reducers and from sulfur-oxidizers most probably evolved into three independent lineages prior to divergence of archaea and bacteria.

Towards the phylogeny of APS reductases and sirohaem sulfite reductases in sulfate-reducing and sulfur-oxidizing prokaryotes.

The genes for adenosine-5'-phosphosulfate (APS) reductase, aprBA, and sirohaem sulfite reductase, dsrAB, from the sulfur-oxidizing phototrophic bacterium Chromatium vinosum strain D (DSMZ 180(T)) were cloned and sequenced. Statistically significant sequence similarities and similar physicochemical properties suggest that the aprBA and dsrAB gene products from Chr. vinosum are true homologues of their counterparts from the sulfate-reducing chemotrophic archaeon Archaeoglobus fulgidus and the sulfate-reducing chemotrophic bacterium Desulfovibrio vulgaris. Evidence for the proposed duplication of a common ancestor of the dsrAB genes is provided. Phylogenetic analyses revealed a greater evolutionary distance between the enzymes from Chr. vinosum and D. vulgaris than between those from A. fulgidus and D. vulgaris. The data reported in this study are most consistent with the concept of common ancestral protogenotic genes both for dissimilatory sirohaem sulfite reductases and for APS reductases. The aprA gene was demonstrated to be a suitable DNA probe for the identification of apr genes from organisms of different phylogenetic positions. PCR primers and conditions for the amplification of apr homologous regions are described.