A Gram-negative bacterium designated ww 10T was isolated by plating dilutions from forest soil in Zhejiang province, China. Strain ww 10T was investigated by polyphasic taxonomic study including phenotypic and phylogenetic analysis. Cells of ww 10T were Gram-negative, strictly aerobic, motile with peritrichous flagella and rod-shaped. The strain grew optimally at 30-37ºC and pH 6.0-8.0. The major fatty acids were C18:1ω7C, cyclo-C19:0ω8C and C16:0. The respiratory quinones contained a large amount of Q-10, a moderate component of Q-9 and a minor of Q-8. The G+C content of genomic DNA was about 67.3 mol%. Phylogenetic analysis revealed that strain ww 10T belongs to the phyletic cluster of genus Azospirillum and displayed 16S rRNA gene sequence similarity lower than 96.3% to the four closest described species of the genera Azospirillum and Roseomonas. Results of polyphasic taxonomic analysis showed that strain ww 10T represents a novel species in the genus Azospirillum, for which the name Azospirillum palatum sp. nov., is proposed. The type strain is ww 10T (=LMG 24444T=KCTC 13200T=CCTCC AB 207189T).
The present study was designed to develop a reliable experimental protocol for detecting and genotyping amplified fragment length polymorphism (AFLP) markers in the commercially important edible mushroom Hypsizygus marmoreus; and to use the markers to evaluate the genetic polymorphisms and phylogenetic relationships among 19 strains of H. marmoreus. Using a set of ten primer pairs, 609 AFLP markers were identified, of which 532 were found segregating among 19 cultivated varieties and laboratory stock strains. An estimate of genetic relationships among the varieties/strains based on the AFLP markers was obtained by primary phylogenetic analysis using UPGMA. Our data demonstrate abundant genetic variation in the natural population of H. marmoreus and facilitate further analysis of genetic divergence within the species. The present study is useful for understanding the genetic structure of this species and uncovering genetic control of economically important traits for efficient breeding programs.
A polyphasic study was undertaken to establish the taxonomic positions of two isolates, SK15T and SK60T, from soil samples that were found to have morphological and chemical properties consistent with Kitasatospora strains. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strains SK15T and SK60T form novel evolutionary lineages within the radiation of the genus Kitasatospora and share the highest 16S rRNA gene sequences similarities with their closest relatives, Kitasatospora setae IAM 15325T (97.8%) and Kitasatospora mediocidica IAM 15162T (97.5%), respectively. However, the results of DNA-DNA hybridization experiment and phenotypic data demonstrated that strains SK15T and SK60T are distinct from their closest phylogenetic neighbors and other Kitasatospora species. For chemotaxonomic characteristics, the cell-wall peptidoglycan of strains contained both meso- and LL-diaminopimelic acids as the diamino acids, the predominant quinone system was MK-9(H6) and MK-9(H8), whole-cell hydrolysates were rich in galactose, mannose and ribose, and the major fatty acids were C16:0, anteiso-C15:0, iso-C15:0 and iso-C16:0. On the basis of both phenotypic and phylogenetic evidence, strains SK15T and SK60T were assigned to represent two novel species of the genus Kitasatospora, for which the names Kitasatospora saccharophila sp. nov. (type strain SK15T=JCM 14559T=KCTC 19566T) and Kitasatospora kazusanensis sp. nov. (type strain SK60T=JCM 14560T=KCTC 19565T) are proposed. It is also proposed that Streptomyces atroaurantiacus should be transferred to the genus Kitasatospora as Kitasatospora atroaurantiaca comb. nov. (type strain NBRC 14327T=DSM 41649T).
The biosorptive capacity of Cd(II) and Cu(II) by lyophilized cells of Pseudomonas stutzeri was investigated based on Langmuir and Freundlich isotherms and biosorption kinetics were analyzed using first order kinetic with different initial metal concentrations. Biosorptive capacity for Cd(II) and Cu(II) decreased with an increment of metal concentration, reaching 43.5 and 36.2 mg/g at the initial concentration of 300 mg/L. Biosorption capacity for both metal ions was increased with increasing pH. The optimum pH for biosorption rate of Cu(II) and Cd(II) was pH 5; above pH 5.0 the metal cations came to be precipitated. The experimental data showed a better fit with the Langmuir model over the Freundlich model for both metal ions throughout the range of initial concentrations. The maximum sorptive capacity (q max) obtained from the Langmuir equation for Cd(II) and Cu(II) were 47.86 (r2=0.99) and 33.16 (r2=0.99), respectively. The bacterial cells have more affinity to adsorb cadmium than copper. The first order kinetic was well fitted to the experimental data for initial concentrations from 30 to 100 mg/L during reaction times of 250 min. These results suggest that biosorption of Cu(II) and Cd(II) by lyophilized cells of P. stutzeri is a potential metal removal strategy.
Resistance to a 1% or higher concentration of NaCl is an important trait for taxonomic discrimination of species in the family Rhizobiaceae. However, we have little knowledge about how much salt rhizobia require. In this study, we examined the requirement of NaCl for growth in relation to the NaCl sensitivity in the pathogenic Agrobacterium species. Consistent with the previous salt resistance data, the standard Luria Bertani medium containing 0.5% NaCl (LB) permitted A. tumefaciens and A. vitis strains to grow well, but not A. rhizogenes strains. In contrast, LB lacking NaCl (LB-NaCl) allowed the A. rhizogenes and A. tumefaciens strains to grow well but not the A. vitis strains. In LB-NaCl, viability of A. vitis strains decreased 500-fold in 24 h. The addition of KCl, MgCl2 or MgSO4 to LB-NaCl restored the growth of A. vitis strains. These data indicate higher salt requirements in A. vitis than those in A. tumefaciens and A. rhizogenes and adaptability of A. tumefaciens to salt-insufficient environments. An A. rubi strain was salt dependent like A. vitis. The experiment was extended to strains in related genera. Checking growth on the two media was very easy, gave a new trait and clear results, and thereby proved useful as an additional method for taxonomic identification.
A photoorganotrophic alphaproteobacterium designated strain G2-11T was isolated from submerged paddy soil. This bacterium had relatively large, oval to rod-shaped cells (2.0-3.0×3.0-10 μm). Cells were motile by means of single polar flagella. The color of phototrophically growing cultures was reddish-brown. The cell extract had absorption maxima at 375, 465, 492, 529, 592, 804, and 844 nm, indicating the presence of bacteriochlorophyll a and carotenoides of the spirilloxanthin series. Vesicular intracytoplasmic membranes were present. The main component of cellular fatty acids was C18:1ω7c. Ubiquinone-10 and rhodoquinone-10 were the major quinones. A 16S rRNA gene sequence analysis revealed that the isolate is closest to the acidophilic aerobic photosynthetic bacterium Acidisphaera rubrifaciens strain HS-AP3T (93.3% similarity). The G+C content of genomic DNA is 67.8 mol%. The name Rhodovastum atsumiense gen. nov., sp. nov. is proposed for the novel isolate. The type strain is strain G2-11T (=NBRC 104268T=KCTC 5708T).