Hidetoshi Matsuyama

Dietzia psychralcaliphila sp. nov., a novel, facultatively psychrophilic alkaliphile that grows on hydrocarbons

A novel, facultatively psychrophilic alkaliphile that grows on a chemically defined medium containing n-alkanes as the sole carbon source was isolated from a drain of a fish product-processing plant. The isolate was an aerobic, non-motile, gram-positive bacterium. The bacterium was catalase-positive and oxidase-negative. The cell wall contained meso-diaminopimelic acid, arabinose and galactose; the glycan moiety of the cell wall contained acetyl residues. The G+C content of the DNA was 69.6 mol %. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was closely related to members of the genus Dietzia (96.1-96.8% similarity). Comparisons of phenotypic and chemotaxonomic characteristics between the isolate and the two known Dietzia species showed that they were very similar. However, the isolate differed from the two known Dietzia species in growth temperature range and certain physiological characteristics. DNA-DNA hybridization revealed that the isolate had 38.4 and 49.7% relatedness, respectively, to Dietzia maris and Dietzia natronolimnaea. On the basis of the physiological and biochemical characteristics, the phylogenetic position as determined by 16S rRNA gene analysis and DNA-DNA relatedness, it is concluded that the isolate should be designated as a novel species, for which the name Dietzia psychralcaliphila sp. nov. is proposed. The type strain is ILA-1T (= JCM 10987T = IAM14896T = NCIMB 13777T).

Purification and characterization of a catalase from the facultatively psychrophilic bacterium Vibrio rumoiensis S-1(T) exhibiting high catalase activity.

Catalase from the facultatively psychrophilic bacterium Vibrio rumoiensis S-1(T), which was isolated from an environment exposed to H(2)O(2) and exhibited high catalase activity, was purified and characterized, and its localization in the cell was determined. Its molecular mass was 230 kDa, and the molecule consisted of four identical subunits. The enzyme, which was not apparently reduced by dithionite, showed a Soret peak at 406 nm in a resting state. The catalytic activity was 527,500 U. mg of protein(-1) under standard reaction conditions at 40 degrees C, 1.5 and 4.3 times faster, respectively, than those of the Micrococcus luteus and bovine catalases examined under the same reaction conditions, and showed a broad optimum pH range (pH 6 to 10). The catalase from strain S-1(T) is located not only in the cytoplasmic space but also in the periplasmic space. There is little difference in the activation energy for the activity between strain S-1(T) catalase and M. luteus and bovine liver catalases. The thermoinstability of the activity of the former catalase were significantly higher than those of the latter catalases. The thermoinstability suggests that the catalase from strain S-1(T) should be categorized as a psychrophilic enzyme. Although the catalase from strain S-1(T) is classified as a mammal type catalase, it exhibits the unique enzymatic properties of high intensity of enzymatic activity and thermoinstability. The results obtained suggest that these unique properties of the enzyme are in accordance with the environmental conditions under which the microorganism lives.

Assignment of Vibrio sp. strain ABE-1 to Colwellia maris sp. nov., a new psychrophilic bacterium.

A psychrophilic bacterium, previously described as Vibrio sp. strain ABE-1T, has been reassigned by phenotypic characterization, chemotaxonomic analysis and 16S rRNA phylogenetic analysis. The organism was curved rods and it could reduce nitrate to nitrite and hydrolyse gelatin and DNA, but not chitin. NaCl was required for growth. This strain was susceptible to the vibriostatic compound O/129. The major isoprenoid quinone was ubiquinone-8 and the DNA G + C content was 39.4 mol%. The whole-cell fatty acids comprised saturated and monounsaturated fatty acids with 10-18 C atoms; saturated and monounsaturated C16 fatty acids were predominant. Strain ABE-1T contained the unique trans-unsaturated fatty acid, 9-trans-hexadecenoic acid. Although strain ABE-1T has been identified as a Vibrio species, the strain did not ferment glucose. Phylogenetic analysis based on 16S rRNA sequencing indicated that strain ABE-1T was more closely related to Colwellia species than to Vibrio species. However, strain ABE-1T differed from other reported Colwellia species in terms of phylogenetic position, some phenotypic characteristics, chemotaxonomic analysis and relatedness by DNA-DNA hybridization. Accordingly, the name Colwellia maris is proposed. The type strain is ABE-1T (= JCM 10085T).

Microbacterium kitamiense sp. nov., a new polysaccharide-producing bacterium isolated from the wastewater of a sugar-beet factory

Two strictly aerobic, heterotrophic and mesophilic new organisms, strains Kitami A1 and Kitami C2T, were isolated from the wastewater of a sugar-beet factory in Kitami City, Hokkaido, Japan. In batch cultures, these organisms produced both insoluble and soluble exopolysaccharides (EPSs) utilizing sucrose as the sole carbon source. The G + C contents of the strains Kitami C2T and Kitami A1 were 69.2 mol%. Both strains had anteiso-C15:0 acid, anteiso-C17:0 acid and iso-C16:0 as major components. The major isoprenoid quinones from these strains included menaquinone-11 and menaquinone-12. Physiological and biochemical characterization, phylogenetic analysis and DNA-DNA relatedness indicated that these two organisms are new species of the genus Microbacterium, for which the name Microbacterium kitamiense is proposed. The type strain of M. kitamiense is strain Kitami C2T (= JCM 10270T).

Sphingobacterium kitahiroshimense sp. nov., isolated from soil

A novel exopolysaccharide-degrading bacterium, designated strain 10C(T), was isolated from soil from Kitahiroshima city, Hokkaido, Japan. The novel isolate was Gram-negative, strictly aerobic and chemoheterotrophic. The DNA G+C content was 36.9 mol%. Major fatty acids were C(16 : 1)omega7c, iso-C(15 : 0) 2-OH, iso-C(15 : 0) and iso-C(17 : 0 )3-OH. 16S rRNA gene sequence analysis and chemotaxonomic and morphological data indicated that the novel strain clearly belonged to the genus Sphingobacterium. Based on phenotypic properties and DNA-DNA hybridization data, the new isolate was assigned to the genus Sphingobacterium as Sphingobacterium kitahiroshimense sp. nov. The type strain is 10C(T) (=JCM 14970(T)=NCIMB 14398(T)).

Bacillus polygoni sp. nov., a moderately halophilic, non-motile obligate alkaliphile isolated from indigo balls.

A moderately halophilic, obligate alkaliphile (growth range pH 8-12), designated strain YN-1(T), was isolated from indigo balls obtained from Ibaraki, Japan. The cells of the isolate stained Gram-positive, and were aerobic, non-motile, sporulating rods which grew optimally at pH 9. The strain grew in 3-14% NaCl with optimum growth in 5% NaCl. It hydrolysed casein and Tweens 20, 40 and 60, but not gelatin, starch, DNA or pullulan. Its major isoprenoid quinone was MK-7 and its cellular fatty acid profile mainly consisted of anteiso-C(15:0), anteiso-C(17:0) and anteiso-C(17:1). 16S rRNA phylogeny suggested that strain YN-1(T) was a member of group 7 (alkaliphiles) of the genus Bacillus, with the closest relative being Bacillus clarkii DSM 8720(T) (similarity 99.5%). However, DNA-DNA hybridization showed a low DNA-DNA relatedness (7%) of strain YN-1(T) with B. clarkii DSM 8720(T). Owing to the significant differences in phenotypic and chemotaxonomic characteristics, and phylogenetic and DNA-DNA relatedness data, the isolate merits classification as a new species, for which the name Bacillus polygoni is proposed. The type strain of this species is YN-1(T) (=JCM 14604(T)=NCIMB 14282(T)).

Psychromonas marina sp. nov., a novel halophilic, facultatively psychrophilic bacterium isolated from the coast of the Okhotsk Sea.

A facultatively psychrophilic bacterium, strain 4-22T, was isolated from a cold current off the Monbetsu coast of the Okhotsk Sea in Hokkaido, Japan. The isolate was a rod-shaped facultative anaerobe that reduced nitrate to nitrite and hydrolysed starch, DNA and alginic acid, but not chitin or gelatin. The isolate grew at 0 degrees C, but not at 26 degrees C; the optimum growth temperature was 14-16 degrees C. NaCl was required for growth. The DNA G+C content was 43.5 mol%. The whole-cell fatty acids consisted of significant amounts of an unsaturated fatty acid, C16:1, and a saturated fatty acid, C16:0. A polyunsaturated fatty acid, docosahexaenoic acid (C22:6), was also detected (1.6%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 4-22T was closely related to Psychromonas antarctica (95.7% similarity). DNA-DNA hybridization revealed a relatedness of 31% between strain 4-22T and P. antarctica. Based on physiological and biochemical characteristics and the phylogenetic position as determined by 16S rRNA gene analysis and DNA-DNA relatedness, it is concluded that the isolate represents a novel species, for which the name Psychromonas marina sp. nov. is proposed. The type strain is 4-22T (= JCM 10501T = IAM 14899T = NCIMB 13792T).

Assignment of Pseudomonas sp. strain E-3 to Pseudomonas psychrophila sp. nov., a new facultatively psychrophilic bacterium

A facultatively psychrophilic bacterium, previously described as Pseudomonas sp. strain E-3, has been reassigned by phenotypic characterization, chemotaxonomic analysis, DNA-DNA hybridization, and 16S rRNA gene phylogenetic analysis. The organism was a gram-negative, aerobic. straight rod with polar flagella. It was catalase positive and oxidase positive, able to grow at -1 degree C but not at 40 degree C, and produced acid from D-glucose under aerobic conditions. The major isoprenoid quinone was ubiquinone-9, and the DNA G + C content was 57.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the bacterium is a member of the genus Pseudomonas and was closest to Pseudomonas fragi. Determination of the DNA-DNA relatedness between strain E-3 and P. fragi revealed too low a level of homology (47.9%-51.3%) to identify them as the same species. On the basis of phenotypic characteristics, phylogenetic analysis, and DNA-DNA relatedness data, it is concluded that strain E-3 represents an individual species. Accordingly, the name Pseudomonas psychrophila is proposed. The type strain is E-3T (= JCM 10889).

Effects of ultraviolet-B irradiation on the cuticular wax of cucumber (Cucumis sativus) cotyledons

Cucumber seedlings were grown under three doses of supplemental ultraviolet-B (UV-B) irradiation to examine the effects on the surface structure of the cotyledons. Medium and high doses of irradiation induced glazing (formation of translucent, glossy layers) on the adaxial surfaces of cotyledons, especially those exposed to a high dose of UV-B. Observation with a scanning electron microscope revealed that the adaxial surfaces of cotyledons exposed to a medium dose of UV-B and controls became rough in appearance, but unevenness of the surface was not apparent in cotyledons irradiated with a high dose of UV-B. UV-B irradiation affected the types and amounts of alkanes and primary alcohols, the main components of cucumber cuticular wax. Based on cotyledon area, the amounts of these components were significantly higher in cotyledons irradiated with a medium dose of UV-B than in controls. This effect could be a consequence of small cotyledon area and constant wax production in the cotyledons irradiated with a medium dose of UV-B. The distribution patterns of homologs within the alkane and primary alcohol fractions shifted during growth to longer alkyl chain length in the control cotyledons. UV-B irradiation repressed these changes, suggesting that UV-B acts on cuticular wax biosynthetic pathways.

Psychrobacter piscatorii sp. nov., a psychrotolerant bacterium exhibiting high catalase activity isolated from an oxidative environment

A Gram-negative, non-motile, psychrotolerant bacterium exhibiting high catalase activity, designated strain T-3-2(T), was isolated from a drain of a fish-processing plant. Its catalase activity was 12 000 U (mg protein)(-1), much higher than the activity of the other Psychrobacter strains tested. The strain grew at 0-30 degrees C and in the presence of 0-12 % NaCl. The predominant isoprenoid quinone was ubiquinone-8 (Q-8), and C(16 : 1)omega9c and C(18 : 1)omega9c were the predominant cellular fatty acids. The DNA G+C content of strain T-3-2(T) was 43.9 mol%. 16S rRNA gene sequence phylogeny suggested that strain T-3-2(T) is a member of the genus Psychrobacter, with the closest relatives being the type strains of Psychrobacter nivimaris (99.2 % similarity), P. aquimaris (98.7 %) and P. proteolyticus (98.5 %). DNA-DNA hybridization showed less than 65 % relatedness with these strains. A phylogenetic tree based on gyrB gene sequences was more reliable, with higher bootstrap values than the 16S rRNA gene sequence-based tree. The result also differentiated the isolate from previously reported Psychrobacter species. Owing to the significant differences in phenotypic and chemotaxonomic characteristics and the phylogenetic and DNA-DNA relatedness data, the isolate merits classification within a novel species, for which the name Psychrobacter piscatorii sp. nov. is proposed. The type strain is T-3-2(T) (=JCM 15603(T) =NCIMB 14510(T)).