- Volume 41, Issue 1, 1991

A new microaerophilic, spirally curved, rod-shaped bacterium was isolated from the gastric mucosa of a pigtailed macaque (Macaca nemestrina). The gram-negative cells of this bacterium are oxidase, catalase, and urease positive and strongly resemble Helicobacter pylori (Campylobacter pylori) cells. Like H. pylori, this organism does not metabolize glucose, does not reduce nitrate or produce indole, does not produce H2S from triple sugar iron agar, does not hydrolyze hippurate or esculin, and does not grow in the presence of 1% glycine, 1.5% salt, or 1% bile. Also like H. pylori, it is resistant to nalidixic acid and susceptible to cephalothin. However, unlike H. pylori, the colorless colonies are flat and have irregular edges. This organism has a unique cellular fatty acid composition, forming a new gas-liquid chromatography group, group K, and a distinctive DNA content (24 mol% guanine plus cytosine). It exhibits less than 10% DNA-DNA homology (as determined by the nylon filter blot method at 65°C) with other members of the genus Helicobacter. Although the levels of DNA relatedness between previously described Helicobacter species and the new organism are low (less than 10%) and the difference in guanine-plus-cytosine content is large (24 versus 36 to 41 mol%), the genus Helicobacter is the only genus in which it is logical to include the organism at this time. We propose that our single strain represents a new species, Helicobacter nemestrinae, and we designate strain T81213-NTB (= ATCC 49396) as the type strain.

Chemotaxonomic, genetic, and phenotypic characteristics of strain VKM Ac-1250T (T = type strain), which was isolated from an association with Streptomyces galilaeus INA 5888, revealed that this actinomycete is a new Glycomyces species, for which the name Glycomyces tenuis is proposed. This new species could be differentiated from Glycomyces harbinensis and Glycomyces rutgersensis by the following characteristics: Thin hyphae (diameter, 0.15 to 0.40 μm) on the substrate mycelium, absence of aerial hyphae, major menaquinone composition [MK-9(H6), MK-10(H6), and MK-11(H6)], certain physiological properties, and high levels of susceptibility to some antibiotics and growth inhibitors. The type strain of G. tenuis is strain VKM Ac-1250 (= INA n-5888).

A new genus, Methylovorus, and one new species are described for a group of restricted facultatively methylotrophic bacteria. Five strains belonging to the new genus are characterized by a low level (5 to 15%) of DNA-DNA homology with type strains of restricted facultative methylobacteria of the genus Methylophilus (M. methylotrophus NCIB 10515T) and obligate methylobacteria of the genus Methylobacillus (M. glycogenes ATCC 29475T). The Methylovorus strains, like Methylophilus and Methylobacillus strains, assimilate methanol via the ribulose monophosphate pathway and do not have α-ketoglutarate dehydrogenase and glyoxylate bypass enzymes. Methylovorus strains are characterized by an enhanced specificity of 6-phosphogluconate-dehydrogenase to NAD (not NADP) the absence of glutamate dehydrogenase, and the presence of the glutamate cycle enzymes for ammonia assimilation. The deoxyribonucleic acid base composition of the Methylovorus strains is 56 to 57 mol% guanine plus cytosine. Their phospholipids are similar to those of Methylobacillus but differ from those of Methylophilus by the occurrence of diphosphatidylglycerol. The fatty acid composition of the strains of all three genera is primarily C16:1ω7 and C16:0, although the Methylophilus, but not Methylovorus, strains also contain two unidentified C17 branched fatty acids. The type species is Methylovorus glucosotrophus sp. nov. The type strain is 6B1 (= UCM B-1475).

Among several hundred bifidobacteria isolated from bovine rumens, eight strains were recognized primarily on the basis of DNA-DNA hybridization results as members of two new distinct DNA homology groups. We studied the morphology, oxygen, carbon dioxide, temperature, and pH requirements, fermentation patterns, end products of glucose fermentation, biochemical reactions, protein electrophoretic patterns, isozyme patterns, DNA homology relationships, and guanine-plus-cytosine contents of these organisms, and we propose that these two groups of strains should be considered new species, Bifidobacterium ruminantium (type strain, strain ATCC 49390) and Bifidobacterium merycicum (type strain, strain ATCC 49391).

We describe a hyperthermophilic archaebacterium, Hyperthermus butylicus gen. nov., sp. nov., that was isolated from flat-sea sediments. This organism is the first extremophilic archaebacterium for which fermentation products have been identified. The type strain is strain DSM 5456.

Yokenella regensburgei and Koserella trabulsii have competed for priority since 1985. The Bacteriological Code was amended in 1986 to include an addition to Rule 24b of the Bacteriological Code by the Judicial Commission. According to the 24b of the Bacteriological Code, the Rules are retroactive. We propose that Yokenella regensburgei has priority over the genus Koserella and the species Koserella trabulsii.

A practical and effective method for the extraction of mitochondrial DNA from Candida species was developed. Zymolyase was used to induce yeast protoplasts, and mitochondrial DNA was extracted from DNase I-treated mitochondrial preparations. Restriction endonuclease analyses of mitochondrial DNAs from 19 isolates representing seven species of Candida (C. albicans, C. kefyr, C. lusitaniae, C. maltosa, C. parapsilosis, C. shehatae, and C. tropicalis) and Lodderomyces elongisporus revealed different cleavage patterns that appeared to be specific for the species. Few common restriction fragments were evident. The genome sizes of the mitochondrial DNAs ranged from 26.4 to 51.4 kilobase pairs, and the guanine-plus-cytosine contents ranged from 20.7 to 36.8 mol%. There was no correlation between the base compositions of nuclear and mitochondrial DNAs. Eight isolates of C. parapsilosis, including the type culture, and an ascosporogenous strain of L. elongisporus, which was once proposed as the teleomorph of C. parapsilosis, had similar mitochondrial DNA molecular sizes (30.2 and 28.8 kilobase pairs); however, restriction endonuclease patterns of these organisms were distinct. These data provide additional support for discrimination of these two species. The results of our experiments demonstrate that mitochondrial DNA analyses may provide useful criteria for the differentiation of yeast species.

The proposals to reinstate Xanthomonas citri (ex Hasse 1915) Gabriel et al. 1989 and X. phaseoli (Smith 1897) Gabriel et al. 1989 are examined in terms of conventional criteria for describing new species. We suggest that the descriptions presented are insufficient in terms of modern practice for the purposes of formal classification in the genus Xanthomonas. To create guidelines for future reinstatements, the Judicial Commission of the International Committee on Systematic Bacteriology is requested to arrange for the preparation and promulgation of minimal standards for Xanthomonas. The pathovars proposed, X. campestris pv. aurantifolii Gabriel et al. 1989 and X. campestris pv. citrumelo Gabriel et al. 1989, are considered to be defective in terms of the International Society for Plant Pathology’s standards for naming pathovars.