Yulin Lestari

Actinokineospora baliensis sp. nov., Actinokineospora cibodasensis sp. nov. and Actinokineospora cianjurensis sp. nov., isolated from soil and plant litter.

Six actinomycete strains isolated from soil and plant-litter samples in Indonesia were studied for their taxonomic position by using a polyphasic approach. Phylogenetically, all the strains were located in the broad cluster of the genus Actinokineospora. Chemotaxonomic data [cell-wall diamino acid, meso-diaminopimelic acid; cell-wall peptidoglycan, type III (A1γ); major sugars, galactose and arabinose; major menaquinone, MK-9(H₄); major fatty acid, iso-C₁₆:₀; major phospholipid, phosphatidylethanolamine] supported the affiliation of all six strains to the genus Actinokineospora. The results of DNA-DNA hybridization with DNA from type strains of Actinokineospora species with validly published names revealed three DNA-DNA relatedness groups. Group I (ID03-0561(T)) showed low relatedness to the other strains studied. The three strains in group II (ID03-0784(T), ID03-0808 and ID03-0809) formed a group with high relatedness (98-100 %) and showed low relatedness to the other strains studied. The two strains in group III (ID03-0810(T) and ID03-0813) showed 58-68 % relatedness to Actinokineospora terrae NBRC 15668(T) and showed low relatedness (2-24 %) to the other strains studied. The description of three novel species is proposed: Actinokineospora baliensis sp. nov., for the single strain in group I (type strain ID03-0561(T) =BTCC B-554(T) =NBRC 104211(T)), Actinokineospora cibodasensis sp. nov., for the strains in group II (type strain ID03-0784(T) =BTCC B-555(T) =NBRC 104212(T)), and Actinokineospora cianjurensis sp. nov., for the strains in group III (type strain ID03-0810(T) =BTCC B-558(T) =NBRC 105526(T)).

Dietzia timorensis sp. nov., isolated from soil.

An actinomycete strain, ID05-A0528(T), was isolated using the SDS-yeast extract pre-treatment method from soil under mahogany (Swietenia mahogani) trees in West Timor, Indonesia, and was examined by using a polyphasic taxonomic approach. Chemotaxonomic and phylogenetic characterizations demonstrated that the novel strain belongs to the genus Dietzia. 16S rRNA gene sequencing studies showed that the strain was related to Dietzia cinnamea (97.2 %). Results of phenotypic and phylogenetic analyses determined that strain ID05-A0528(T) is different from the known species of the genus Dietzia. It is proposed that the isolate should be classified as a representative of a novel species of the genus Dietzia, with the name Dietzia timorensis sp. nov. The type strain is ID05-A0528(T) (=BTCC B-560(T) =NBRC 104184(T)).

Actinophytocola timorensis sp. nov. and Actinophytocola corallina sp. nov., isolated from soil

Two actinomycete strains, ID05-A0653(T) and ID06-A0464(T), were isolated from soils of West Timor and Lombok island, respectively, in Indonesia. 16S rRNA gene sequence analysis clearly demonstrated that the isolates belonged to the family Pseudonocardiaceae and were closely related to the genus Actinophytocola. Strains ID05-A0653(T) and ID06-A0464(T) exhibited 98.1 and 98.2 % 16S rRNA gene sequence similarity, respectively, with Actinophytocola oryzae GMKU 367(T). The isolates grew well on ISP media and produced white aerial mycelium. Short spore chains were formed directly on the substrate mycelium. The isolates contained meso-diaminopimelic acid, arabinose and galactose as cell-wall components, MK-9(H(4)) as the sole isoprenoid quinone, iso-C(16 : 0) as the major cellular fatty acid and phosphatidylethanolamine as the diagnostic polar lipid. The DNA G+C contents of strains ID05-A0653(T) and ID06-A0464(T) were 69.7 and 71.2 mol%, respectively. On the basis of phenotypic characteristics, DNA-DNA relatedness and 16S rRNA gene sequence comparisons, strains ID05-A0653(T) and ID06-A0464(T) each represent a novel species of the genus Actinophytocola, for which the names Actinophytocola timorensis sp. nov. (type strain ID05-A0653(T)  = BTCC B-673(T)  = NBRC 105524(T)) and Actinophytocola corallina sp. nov. (type strain ID06-A0464(T)  = BTCC B-674(T)  = NBRC 105525(T)) are proposed.

Characterization of Xylanase Streptomyces spp. SKK1-8

Streptomyces spp. SKK1-8 producing xylanase was isolated from soil sample from Sukabumi West Java. The xylanase have an optimum condition at pH 6 and 50 0 C. Addition of 5 mM Cu 2+ decreased the xylanase activity up to about 77%, whereas not by other cations. The xylanase was stable at 3 0 C for 48 hours, and the enzyme half lifetime was 1 hour 45 minute at 50 0 C. This xylanase showed the highest activity on oatspelt xylan, and their molecular masses were estimated approximately 16.80, 15.21, and 13.86 kDa. HPLC analysis showed that xylosa and arabinosa were the main hydrolytic product of birchwood xylan. Key words: xilanase, Streptomyces spp., characterization, zymogram and SDS-PAGE, stability

Streptomyces baliensis sp. nov., isolated from Balinese soil

The taxonomic positions of actinomycete strains ID03-0915T and ID03-0825, isolated from soil on the Indonesian island of Bali, were examined using a polyphasic taxonomic approach. The morphological and chemotaxonomic characteristics of these organisms are typical of the genus Streptomyces. Phylogenetic analyses performed using almost-complete 16S rRNA gene sequences demonstrated that the strains were closely related to Streptomyces glauciniger and Streptomyces lilacinus. However, DNA-DNA hybridization and phenotypic characteristics revealed that the strains differed from known Streptomyces species. Therefore, we conclude that strains ID03-0915T and ID03-0825 (=BTCC B-563) represent a novel species of the genus Streptomyces, for which we propose the name Streptomyces baliensis sp. nov. The type strain is strain ID03-0915T (=BTCC B-608T=NBRC 104276T).

Effect of pH on nitrogenase activity and mineral composition of Medicago truncatula cv. Jemalong and M. polymorpha cv. Serena inoculated with Rhizobium meliloti

The further nodulation, nodule development and nitrogen fixation by nodulated Medicago polymorpha and M. truncatula plants transferred from pH 7.0 to three lower pH conditions (4.5, 5.0 and 5.5) in hydroponic culture was examined. Under these conditions, further nodule initiation by strains CC169 and WSM540 was severely retarded. Nodule development (mg nodule dry weight plant-1) was similar on plants at pH 5.0 and 5.5 to that on plants kept at pH 7.0, but at pH 4.5, it was less. Under the lower pH conditions, the nodules were 2–3 times the mass of those found at pH 7.0. Nitrogen fixation, expressed as µg N2 mg-1 (nodule dry weight) d-1, was largely unaffected by pH, and the apparently lower levels of nitrogen fixation at pH 4.5 could be attributed to an effect on nodule development. The determination of nitrogenase activity by acetylene reduction assay showed a strong influence of pH on the observed rates (per plant, or on a mg nodule dry weight basis). No explanation can be offered for this anomoly, but it does indicate the need for caution in applying the assay in this type of experimentation. The four host x strain combinations showed a similar response to the lower pH conditions, despite the fact that M. polymorha fixed higher levels of nitrogen, at a higher rate per mg nodule dry weight, than M. truncatula.

Culturable and unculturable actinomycetes associated with the sponge Neofibularia from Bira Island, Indonesia

Aims: The diversity of the actinomycete community associated with Neofibularia sp. from Bira Island, Indonesia, has been largely unstudied. This study was undertaken to address the paucity of information in this respect. Methodology and results: Culturable actinomycetes were isolated and cultured on HV medium. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the metagenomic 16S rRNA was used to analyse the structure of the actinomycete community. Five culturable actinomycetes that were isolated belonged to the genus Streptomyces. They showed various degrees of similarity to the reference strains Streptomyces sampsonii (9799%), Streptomyces resistomycificus (97-99%), Streptomyces gougerotii (97-99%), Streptomyces erringtonii (97-99%), and Streptomyces albus (97-99%). The culturable actinomycetes isolates also showed differences in morphological characteristics as compared with the reference strains. The metagenomic analysis suggested that the actinomycete community was dominated by rare actinomycetes. Eight DGGE DNA bands that were obtained had sequences that showed similarities to Ferrithrix thermotolerans (88-94%), Lamia majanohamensis (87-92%), Aciditerrimonas ferrireducens (87-92%), and Thermobispora bispora (85-92%), while 4 bands had sequences similar to Propionibacterium acnes (97-100%) and another band matched sequences belonging to an uncultured bacterium clone (86-87%). The actinomycetes detected by the metagenomic approach were assigned identities that were mostly under 97.5% as compared with reference strains available in Genbank. Conclusion, significance and impact of study: Observations from both culture and DGGE analysis give a better understanding of the diversity and community structure of actinomycetes associated with Neofibularia sp. The culturable actinomycetes were Streptomyces spp., while rare actinomycetes were dominant when the metagenomic approach was adopted. Several of these actinomycetes showed identities below 97% when matched to reference strains, indicating possible novel species associated with the sponge Neofibularia.