- Volume 48, Issue 3, 1998

Four strains that form sporangia with motile sporangiospores and mycelia were isolated from soil samples. Their many sporangia were covered by mycelia. They had glutamic acid, glycine, alanine and meso-diaminopimelic acid as cell wall amino acids (wall chemotype II), acofriose (3-O-methylrhamnose) as a characteristic whole-cell sugar, and menaquinone 9(H6). The taxonomic characteristics of these strains differ from those of the previously described motile actinomycetes. On the basis of the morphological, physiological, chemotaxonomic and phylogenetic analyses, a new genus is proposed, Cryptosporangium, and two new species, Cryptosporangium arvum sp. nov. (type strain IFO 15965T) for strain YU 629-21Tand Cryptosporangium japonicum sp. nov. (type strain IFO 15966T) for strains YU 636-3T, YU 655-31 and YU 656-31.

Rod-shaped, thermophilic bacteria with a sheath-like outer structure (‘toga’) were isolated from hot oilfield water of a North Sea oil reservoir. One of the isolates, designated SJ95T, is an obligately anaerobic, sheathed, Gram-negative, fermentative bacterium capable of reducing elemental sulfur to hydrogen sulfide and tolerating high salt concentrations. The optimum growth conditions for this isolate are 58-60°C and pH 6.5-7.0 with 3-4% NaCl and 0.7% MgSO4.7H2O in the medium. Vitamins are required for growth. Growth is stimulated by yeast extract. Cells of strain SJ95Tvary in size from 1-2 to 40-50 μm in length and are motile with a subpolar flagellation. Cells grown on xylan have xylanase activity, presumably associated with the toga, and glucose isomerase activity was detected in xylose-grown cells. The DNA G+C content is 31 and 34 mol%, determined by the thermal denaturation and HPLC methods, respectively. Phylogenetically, strain SJ95Tis most closely related to Petrotoga miotherma with a 97.7% similarity level between their 16S rDNA sequences. The DNA-DNA reassociation value between the two DNAs was 35.6%. On the basis of differences in genotypic, phenotypic and immunological characteristics, strain SJ95T(= DSM 10674T) is proposed as the type strain of a new species, Petrotoga mobilis. It can be readily distinguished from P. miotherma by its motility.

Previous DNA relatedness studies showed that strains idnentified as Bacillus mycoides segregated into two genetically distinct yet phenotypically similar groups, one being B. mycoides sensu stricto and the other, an unclassified taxon. In the present study, the taxonomic position of this second group was assessed by measuring DNA relatedness and determining phenotypic characteristics of an increased number of B. mycoides strains. Also determined was the second group’s 16S RNA gene sequence. The 36 B. mycoides strains studied segregated into two genetically distinct groups sho wing DNA relatedness of about 30%; 18 strains represented the species proper and 18 the second group with intragroup DNA relatedness for both groups ranging from 70 to 100%. DNA relatedness to the type strains of presently recognized species with G+C contents of approximately 35 mol% (Bacillus alcalophilus, Bacillus cereus, Bacillus circulans, Bacillus lentus, Bacillus megaterium and Bacillus sphaericus) ranged from 22 to 37%. Although shown to be genetically distinct taxa, the two B. mycoides groups exhibited highly similar (98%) 16S RNA sequences. Phylogenetic analyses showed that both B. mycoides and the second group clustered closely with B. cereus. Although not distinguishable by physiological and morphological characteristics, the two B. mycoides groups and B. cereus were clearly separable based on fatty acid composition. The data established that the second B. mycoides group merits recognition as a new species for which the name Bacillus pseudomycoides is proposed. The type strain is NRRL B-617T.

Species of the genus Pseudoalteromonas are frequently isolated from marine ecosystems and appear to be particularly abundant in Antarctic coastal waters. Most Pseudoalteromon as strains isolated from sea ice and underlying seawater samples are phenotypically similar to the species Pseudoalteromonas antarctica and Pseudoalteromonas nigrifaciens. However, a minority of isolates were recognized by phenotypic, DNA-DNA hybridization and 16S rRNA-based phylogenetic studies to represent a distinct genospecies clustering at the periphery of the non-pigmented Pseudoalteromon as species clade. These strains are non-pigmented, halotolerant psychrotrophs that are capable of hydrolysing starch and chitin, and possess a DNA G+C content of 38-39 mol%. It is proposed that this group represents a novel species, Pseudoalteromon as prydzensis sp. nov., for which the type strain is ACAM 620T.

Sequences of the 16S rRNA gene were determined for three strains of aerobic bacteriochlorophyll a-containing bacteria isolated from soil. The sequences of two strains (NS89Tand NS102) were identical for approximately 1500 nucleotides. Phylogenetic analysis revealed that the three strains belonged to the α-1 subclass of the Proteobacteria, constituting one line of descent. The three strains are comparatively related to Roseococcus thiosulfatophilus, which is an aerobic bacteriochlorophyll a-containing bacterium. The 16S rRNA gene sequence similarity and the DNA-DNA relatedness allow the proposal of two new genera, Craurococcus gen. nov. and Paracraurococcus gen. nov. The type species are Craurococcus roseus sp. nov. and Paracraurococcus ruber sp. nov., and their type strains are NS130T(=JCM 99331T) and NS89T(=JCM 9931T), respectively.

To investigate whether 16S-23S rDNA (rDNA) spacer region length polymorphisms are suitable for the identification of Staphylococcus strains, the 16S-23S rDNA intergenic spacer region lengths of 221 strains belonging to 31 species were studied by using a PCR-based method. Each species presented a specific 16S-23S pattern made of 1-8 fragments ranging from 104 to 771 bp, with the exception of the species Staphylococcus warneri, Staphylococcus caprae and Staphylococcus piscifermentans, which presented larger or smaller fragments. Very few species showed more than one pattern, Staphylococcus saprophytics subsp. saprophytics and Staphylococcus aureus being the most heterogeneous species (five different patterns for eight strains). Five clinical strains that could not be identified at the species level by phenotypical tests were finally identified using this method. Discrimination between some species that showed close patterns (Staphylococcus cohnii/Staphylococcus chromogenes/Staphylococcus equorum, Staphylococcus aureus/Staphylococcus intermedius, Staphylococcus sciuri/Staphylococcus pasteuri/Staphylococcus gallinarum, Staphylococcus delphini/Staphylococcus felis, Staphylococcus vitulus/Staphylococcus auricularis) was further achieved after Dral digestion of the PCR products. Although it does not allow discrimination of subspecies, the use of 16S-23S spacer region length data determined by PCR-mediated amplification is suitable for the identification of the 31 Staphylococcus species tested in this study. The method is rapid, easy and may be a useful tool for the identification of Staphylococcus species in the clinical microbiology laboratory.

Phylogenetic analyses of 165 rRNA gene sequences showed that the Gramnegative aromatic- and chloroaromatic-degrading Pseudomonas sp. strain HV3 carrying the mega-plasmid pSKY4 belongs to the genus Sphingomonas. The 165rRNA sequence is most related to Sphingomonas chlorophenolica strains ATCC 33790T(98-5%) and SR3 (98.4%) and Sphingomonas sp. SS86 (98.4%). The G+C content was 64 mol%, and the DNA-DNA-hybridization-based relative homology of strain HV3 to the S. chlorophenolica ATCC 33790Tand S. chlorophenolica RA2 was 59.6% and 35.9%, respectively. The results showed that although strain HV3 is related to S. chlorophenolica it differs in certain characteristics. It is therefore proposed to reclassify Pseudomonas sp. strain HV3 as Sphingomonas sp. HV3.

Streptococcus suis 16S rDNA from selected serotypes has been sequenced and compared with the 16S rDNA sequences from serotypes 1 and 2 present in GenBank. After alignment the sequenced serotypes show clusters of variation. Based on these clusters, a limited phylogenetic tree showing the relationships of all of the serotypes was constructed.

To investigate the intraspecies heterogeneity within the 16S rRNA gene of Mycoplasma hominis, five isolates with diverse antigenic profiles, variable/identical P120 hypervariable domains, and different 16S rRNA gene RFLP patterns were analysed. The 16S rRNA gene from the rrnB operon was amplified by PCR and the PCR products were sequenced. Three isolates had identical 16S rRNA sequences and two isolates had sequences that differed from the others by only one nucleotide.

Two strains of ballistoconidium-forming yeasts, isolated from plants collected in the south-east seacoast of Bangkok, Thailand, were described. The strains (K-272Tand K-337T) were assigned to the genera Bullera and Kockovaella, respectively, based on morphological and chemotaxonomical characteristics. Phylogenetically, strain K-272Tis close to Bullera hannae, and strain K-337Tis close to Kockovaella thailandica and Kockovaella imperatae. These two strains represent new species based on DNA-DNA reassociation experiments.Bullera penniseticola Takashima et Nakase sp. nov. and Kockovaella sacchari Takashima et Nakase sp. nov. are proposed for K-272T(= JCM 9857T) and K-337T(= JCM 9858T), respectively.

We request an Opinion of the Judicial Commission regarding rejection of the species Methanothrix soehngenii VPHuser, Wuhrmann and Zehnder 1983, 439, and the genus Methanothrix VPHuser, Wuhrmann and Zehnder 1983, 439, as nomina confusa because their descriptions were based on the characterization of an impure type strain, strain OpfikonT. We also propose the transfer of Methanothrix thermophila VP Kamagata et al. 1992, 465, to the genus Methanosaeta as Methanosaeta thermophila comb. nov.