A novel actinomycete strain, SMC 256 T , which developed small, globose sporangia at the ends of long sporangiophores on aerial mycelium, was isolated from soil collected in a mountain forest of Thailand. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SMC 256 T belonged to the genus Kutzneria, and the closest phylogenetically related species were Kutzneria buriramensis BCC 29373 T (98.9 % 16S rRNA gene sequence similarity), Kutzneria kofuensis ATCC 27102 T (98.2 %), Kutzneria albida ATCC 25243 T (97.9 %) and Kutzneria viridogrisea ATCC 25242 T (97.4 %). The DNA-DNA relatedness values that distinguished strain SMC 256 T from previously described members of the genus Kutzneria were significantly below 70 %. The G+C content of the genomic DNA was 71.8 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars consisted of rhamnose, ribose, mannose, glucose and galactose. The predominant menaquinone was MK-9(H 4 ). Mycolic acids were not detected. The diagnostic phospholipids were hydroxyphosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, unidentified phosphoglycolipids, unidentified phospholipids and an unidentified lipid. The predominant cellular fatty acids were iso-C 16 : 0 , C 17 : 1 and C 17 : 0 10-methyl. Following the evidence of phenotypic, chemotaxonomic and genotypic studies, it is proposed that strain SMC 256 T represents a novel species in the genus Kutzneria, namely Kutzneria chonburiensis sp. nov. The type strain is SMC 256 T (5BCC 72675 T 5NBRC 110610 T ).The genus Kutzneria was proposed by Stackebrandt et al. (1994) and classified in the family Pseudonocardiaceae. So far, this genus has consisted of four species: Kutzneria viridogrisea (type species), Kutzneria albida, Kutzneria kofuensis (Stackebrandt et al., 1994) and Kutzneria buriramensis (Suriyachadkun et al., 2013). Cells are Gram-stainpositive, non-acid-fast and aerobic. Large, globose sporangia (diameter, 10-48 mm) develop and contain rod-or ovalshaped, non-motile spores at the ends of long sporangiophores (length, .50 mm) on aerial mycelium. Substrate mycelium fragments into rod-shaped elements. Vegetative mycelium is white to pale yellow. Optimal growth is observed between 25 and 30 8C. The cell walls of the four established members of the genus Kutzneria contain Nacetylated muramic acid, meso-diaminopimelic acid and no common characteristic sugars. Mycolic acids are not detected. MK-9(H 4 ) is the major isoprenoid quinone. The phospholipid pattern is of type II and usually includes phosphatidylethanolamine, phosphatidylinositol, hydroxyphosphatidylethanolamine and diphosphatidylglycerol. The predominant cellular fatty acids are iso-C 16 : 0 , iso-C 16 : 0 2-OH, C 16 : 0 10-methyl, anteiso-C 17 : 0 , anteiso-C 17 : 0 2-OH and C 17 : 0 10-methyl. The G+C content of the genomic DNA is in the range of 70.3 to 72 mol%.During an investigation of actinomycete diversity in Thaila...

Thymidylate synthase (TS) of Plasmodium dihydrofolate reductase-thymidylate synthase (DHFR-TS) functions as a homodimeric enzyme with two active sites located near the subunit interface. The dimerization is essential for catalysis, since the active site of each subunit contains amino acid residues contributed from the other TS domain. In P. falciparum DHFR-TS, it has been shown that the active sites require Cys-490 from one domain and Arg-470 donated from the other domain. Mutants of these two series can complement one another giving rise to active enzyme. Here, the potential to form cross-species heterodimers between P. falciparum and P. vivax TS has been explored. Formation of cross-species heterodimer was tested by co-transformation of TS-inactive Cys-490 mutants of P. falciparum or P. vivax with corresponding TS-inactive Arg-486 mutants of P. vivax or P. falciparum into thymidine-requiring Escherichia coli. Active heterodimers were detected by subunit complementation and 6-[(3)H]-FdUMP binding assays. All combinations of the mutants tested, except for (Pf)R470A+(Pv)C506Y, were able to form catalytically active cross-species heterodimers. The single active site formed by (Pf)R470D+(Pv)C506Y and (Pv)R486D+(Pf)C490A pairs of cross-species heterodimers has k(cat) and K(m) values similar to those of intra-species heterodimers of P. falciparum and P. vivax. This is the first report to demonstrate that the TS subunit interface between Plasmodium species is sufficiently conserved to allow formation of fully active cross-species heterodimer.

A novel Gram-stain-positive, aerobic actinomycete, designated strain SMC 195, was isolated from soil collected from a mangrove forest in Thailand. The strain produced extensively branched substrate and aerial mycelia. The substrate mycelium was fragmented into rod-shaped elements, and spore chains consisting of smooth and rod-shaped spores were formed on the aerial mycelium. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that SMC 195 represented a member of the genus Pseudonocardia, and the most closely phylogenetically related species were Pseudonocardia yuanmonensisJCM 18055 (99.2 % 16S rRNA gene sequence similarity), Pseudonocardia halophobicaNRRL B-16514 (98.9 %) and Pseudonocardia kujensisNRRL B-24890 (98.7 %). However, the DNA-DNA relatedness values between SMC 195and the closest phylogenetically related species were significantly below 70 %. The G+C content of the genomic DNA was 74±0.8 mol%. The cell wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars consisted of arabinose, galactose, glucose, rhamnose and ribose. The menaquinone was MK-8(H4) only. The major cellular fatty acid was the branched fatty acid iso-C16 : 0 (33.6 %). The polar lipids detected were phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxyphosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and unidentified glycolipids. On the basis of the results from phenotypic, chemotaxonomic and genotypic studies, it is concluded that SMC 195 represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia mangrovi sp. nov. is proposed. The type strain is SMC 195 (=TBRC 7778=NBRC 113150).

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