Characterization of Antimycins - Producing Streptomycete Strain VY46 Isolated from Slovak Soil

ABSTRACT The strain no. VY46 was isolated from agricultural soil of Slovak republic and tested for potential antimicrobial activity against various human pathogens. On the basis of results, strain VY46 significantly inhibited growth of yeast Candida albicans and therefore was used for further characterization. In order to explore the potential bioactivities, extract of the fermented broth culture was prepared with organic solvent extraction method. The ethylacetate extract was subjected to HPLC fractionation against Candida albicans and followed by LC/MS analysis for potential production of anticandidal substances. The analysis resulted in the identification of two antimycins antibiotics, which may be responsible for important anticandidal activity of the strain. On the basis of liquid chromatography and mass spectrometry the antibiotics were identified as Urauchimycin A and Kitamycin A. According tothe results from cultural, morphological, physiological, biochemical and 16S rRNA gene sequence methods, the strain was identified as Streptomyces albidoflavus. In addition, neighbor-joining phylogenetic tree confirmed the relationships of this strain to other members of Streptomyces genera.

Biosynthesis of gold nanoparticles by actinomycete Streptomyces viridogens strain HM10.

Biosynthesis of gold nanoparticles by Streptomycetes from Himalayan Mountain was undertaken for the first time. Out of 10 actinomycete strains tested, four strains (D10, HM10, ANS2 and MSU) showed evidence for the intracellular biosynthesis of gold nanoparticles, among which the strain HM10 showed high potency. Presence of spherical and rod shaped gold nanoparticles in mycelium of the strain HM10 was determined by transmission electron microscopy (TEM) and X-ray diffraction analysis. The average particle size ranged from 18-20 nm. UV spectral analysis indicated that the reduction of chloroauric acid (HAuCl4) occurred within 24 h of reaction period. Further, the strain HM10 showed enhanced growth at 1 and 10 mM concentration of HAuCl4. The gold nanoparticles synthesized by the strain HM10 showed good antibacterial activity against S. aureus and E. coli in well-diffusion method. The potential actinomycete HM10 strain was phenotypically characterized and identified as Streptomyces viridogens (HM10). Thus, actinomycete strain HM10 reported in this study is a newly added source for the biosynthesis of gold nanoparticles.

Microbial populations of crude oil spill polluted soils at the Jordan-Iraq desert (the Badia region) / População microbiana de solos contaminados pelo derramamento de petróleo no deserto Jordão-Iraque (região de Badia)

Microbial populations' inhabitants in crude petroleum contaminated soils were analyzed in relation with the soil characteristics. A noticeable greater decline of bacterial counts and diversity but a prevalence of the genus Pseudomonas over the other identified genera in the fresh contaminated soils as compared to the old ones was observed.

Analisou-se a população microbiana de solos contaminados pelo derramamento de petróleo em função das características do solo. Uma diminuição notável foi observada nas contagens e diversidade bacterianas, mas observou-se a prevalência de Pseudomonas em relação aos demais gêneros identificados em solos recentemente contaminados, quando comparado com solos com contaminação antiga.

Studies on Mutagenesis of Virginiamycin Producing Strain X-435 / 微生物学通报

Streptomyces sp.X-435 isolated from a soil sample collected in the suburbs of Beijing was proved to be a produce Virginiamycin.To improve the productivity of the Virginiamycin of Streptomyces sp.X-435,the spores of strain X-435 were treated with UV.The three types of colony,strawhat,wrinkled,blad,were isolated on Gaose's medium plates after mutation.Among them,the colonies of strawhat type exhibited positive mutation and were picked up as objects of screening.After five generation of mutation,the mutant F5-25-u-28 was selected which potency of Virginiamycin was about 20times higher than that of the beginning strain by flask fermentation and was also genetic stable.

ISOLATION OF ACIDOPHILIC AND ACIDODURIC STREPTOMYCETES USING DISPERSION AND DIFFERENTIAL CENTRIFUGATION APPROACH / 微生物学通报

Technological improvement for microorgnism isolation is important since isolation provides substantial materials for the exploitation of new microbial resources. In this study, a new approach, dispersion and differential cetrifugation (DDC), was applied in the isolation of acidophilic and acidoduric streptomycetes from 12 acid soil samples. Contrast with traditional method, the new approach yielded satisfying results with 2 - 20 times isolation efficiency and good selectivity. 45 representatives out of 249 streptomycetes isolates, which belonged to 12 color groups, showed morphology and cell wall type consistent with streptomycetes. The optimum pH range for their growth were between pH 4.5 - 5.5. It is proved that we succeeded in the rare-streptomycetes isolation using DDC approach.