Novosphingobium oryzae sp. nov., a potential plant-promoting endophytic bacterium isolated from rice roots.

A novel endophytic bacterium, strain ZYY112T, isolated from rice roots, was characterized by a polyphasic approach. In phylogenetic analyses based on 16S rRNA gene sequences, ZYY112T showed highest sequence similarity to Novosphingobium sediminicola HU1-AH51T (97.2 %) and less than 97 % similarity with respect to other Novosphingobium species with validly published names. The DNA G+C content of strain ZYY112T was 60.8 mol%. The level of DNA-DNA relatedness between strain ZYY112T and N. sediminicola DSM 27057T was 33.7 % (reciprocal 5.2 %), which supported the suggestion that ZYY112T represented a novel species of the genus Novosphingobium. Ubiquinone Q-10 was the unique respiratory quinone (100 %). The polar lipid profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, an unknown aminolipid and an unknown phospholipid. The major fatty acids of strain ZYY112T were summed feature 8 (consisting of C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (consisting of C16 : 1ω7c and/or C16 : 1ω6c), C14 : 0 2-OH and C16 : 0. The major polyamine of ZYY112T was spermidine, which is a characteristic trait of the genus Novosphingobium. Characterization by genotypic, chemotaxonomic and phenotypic analysis indicated that strain ZYY112T represents a novel species of the genus Novosphingobium, for which the name Novosphingobium oryzae sp. nov. is proposed. The type strain is ZYY112T ( = ACCC 06131T = JCM 30537T).

Improved myocardial perfusion and cardiac function by controlled-release basic fibroblast growth factor using fibrin glue in a canine infarct model.

OBJECTIVE: Angiogenic therapy is emerging as a potential strategy for the treatment of ischemic heart disease but is limited by a relatively short half-life of growth factors. Fibrin glue (FG) provides a reservoir for controlled-release of growth factors. The aim of this study was to evaluate the effects of basic fibroblast growth factor (bFGF) incorporating FG on angiogenesis and cardiac performance in a canine infarct model. METHODS: Acute myocardial infarction was induced by ligation of the left anterior descending coronary artery (LAD). Group I (n=6) underwent ligation of LAD alone. In Group II, transmural channels were created in the infarct area (n=6). In Group III, non-transmural channels were created to locate FG cylinders containing bFGF (n=6). Eight weeks after operation, myocardial perfusion was assessed by single photon emission computed tomography, cardiac function by echocardiography, and vascular development by immunohistochemical staining. RESULTS: Total vascular density and the number of large vessels (internal diameter ≥50 µm) were dramatically higher in Group III than in Groups I and II at eight weeks. Only the controlled-release group exhibited an improvement in regional myocardial perfusion associated with lower defect score. Animals in Group III presented improved cardiac regional systolic and diastolic functions as well as global systolic function in comparison with the other two groups. CONCLUSIONS: Enhanced and sustained angiogenic response can be achieved by controlled-release bFGF incorporating FG within transmyocardial laser channels, thus enabling improvement in myocardial perfusion and cardiac function.

A Na+/H+ antiporter gene of the moderately halophilic bacterium Halobacillus dabanensis D-8T: cloning and molecular characterization.

A gene encoding a Na(+)/H(+) antiporter was cloned from a chromosomal DNA of Halobacillus dabanensis strain D-8(T) by functional complementation. Its presence enabled the antiporter-deficient Escherichia coli strain KNabc to survive in the presence of 0.2 M NaCl or 5 mM LiCl. The gene was sequenced and designated as nhaH. The deduced amino-acid sequence of NhaH consists of 403 residues with a calculated molecular mass of 43,481 Da, which was 54% identical and 76% similar to the NhaG Na(+)/H(+) antiporter of Bacillus subtilis. The hydropathy profile was characteristic of a membrane protein with 12 putative transmembrane domains. Everted membrane vesicles prepared from E. coli cells carrying nhaH exhibited Na(+)/H(+) as well as Li(+)/H(+) antiporter activity, which was pH-dependent with highest activities at pH 8.5-9.0 and at pH 8.5, respectively. Moreover, nhaH confers upon E. coli KNabc cells the ability to grow under alkaline conditions.

[Cloning, deletion and functional analysis of noeA from Sinorhizobium meliloti 042BM].

042BM noeA was obtained by PCR. It is identical to that of S. meliloti 1021 at 99% level, and similarity of their NoeA is 97%. In addition, it was found that this protein shares significant homology with the SAM-dependent methyltransferase of Mesorhizobium sp. BNC1 (32% similarity), and the similarity of its 303-362 region to the 160- 220 region of Ll11 methyltransferases of E. coli (PrmA) is 41%. Compared to 042BM, the noeA deletion mutant 042BMA-Km showed different degrees of increase in number of nodule, fresh weight of nodule and plant top dry weight on alfalfa cultivars of Putong Zihua, Baoding, Ningxia, Baifa and Aohan, but decrease on Milu. However, this mutant has no significant change in ability to nodulate cultivars of Huanghou and Zahua. Hence, noeA is involved in alfalfa cultivar-specific nodulation.

Salt-tolerance genes involved in cation efflux and osmoregulation of Sinorhizobium fredii RT19 detected by isolation and characterization of Tn5 mutants.

Salt-tolerance genes of Sinorhizobium fredii RT19 were identified by the construction and screening of a transposon Tn5-1063 library containing over 30,000 clones. Twenty-one salt-sensitive mutants were obtained and five different genes were identified by sequencing. Eight mutants were found with disruptions in the phaA2 gene, which encodes a cation efflux system protein, while mutations in genes encoding other cation effux system proteins were found in seven (phaD2), two (phaF2) and two (phaG2) mutants. A mutation in the metH gene, encoding 5' methyltetrahydrofolate homocysteine methyltransferase, was found in two of the salt sensitive strains. Growth experiments showed that phaA2, phaD2, phaF2 and phaG2 mutants were hypersensitive to Na+/Li+ and slightly sensitive to K+ and not sensitive to sucrose and that metH mutants were highly sensitive to any of Na+, Li+, K+ and sucrose. Na+ intracellular content measurements established that phaA2, phaD2, phaF2 and phaG2 are mainly involved in the Na+ efflux in S. fredii RT19. Recovery of growth of the metH mutants incubated with different concentrations of NaCl could be obtained by additions of methionine, choline and betaine, which showed that the metH gene is probably involved in osmoregulation in S. fredii RT19.