Production of polypeptide antibiotic from Streptomyces parvulus and its antibacterial activity

A highly potent secondary metabolite producing actinomycetes strain is isolated from marine soil sediments of Visakhapatnam sea coast, Bay of Bengal. Over all ten strains are isolated from the collected soil sediments. Among the ten actinomycetes strains the broad spectrum strain RSPSN2 was selected for molecular characterization, antibiotic production and its purification. The nucleotide sequence of the 1 rRNA gene (1261 base pairs) of the most potent strain evidenced a 96% similarity with Streptomyces parvulus 1044 strain, Streptomyces parvulus NBRC 13193 and Streptomyces parvulus BY-F. From the taxonomic features, the actinomycetes isolate RSPSN2 matches with Streptomyces parvulus in the morphological, physiological and biochemical characters. Thus, it was given the suggested name Streptomyces parvulus RSPSN2. The active metabolite was extracted using ethyl acetate (1:3, v/v) at pH 7.0. The separation of active ingredient and its purification was performed by using both thin layer chromatography (TLC) and column chromatography (CC) techniques. Spectrometric studies such as UV-visible, FTIR, and NMR and mass were performed. The antibacterial activity of pure compound was performed by cup plate method against some pathogenic bacteria including of streptomycin resistant bacteria like (Pseudomonas mirabilis. Pseudomonas putida and Bacillus cereus). In conclusion, the collected data emphasized the fact that a polypeptide antibiotic (Actinomycin D) was produced by Streptomyces parvulus RSPSN2.

Drug susceptibility test for 16 Mycobacteria tuberculosis isolates from patients with cutaneous tuberculosis / 中华皮肤科杂志

Objective To test the drug susceptibility of 16 Mycobactena tuberculosis isolates from patients with cutaneous tuberculosis,and to provide a basis for the treatment of this entity.Methods Sixteen strains of mycobacterium were isolated from patients with cutaneous tuberculosis.and they were consistently identified as M.tuberculosis by biochemistry and molecular biology.Absolute concentration method was used to test the susceptibility of these isolates to isoniazid.streptomycin.rifampicin and ethambutol.For two strains resistant to streptomycin,PCR and sequencing were performed to analyse the mutation of rpsL gene.Results Out ofthe 16 strains of M tuberculosis.2 were resistant to streptomycin but sensitive to isoniazid,rifampicin and ethambutol,and 14 were sensitive to isoniazid,streptomycin,rifampicin and ethambutol.Sequencing of the rpsL gene revealed a mutation of AAG to AGG at codon 43 in one streptomycinresistant strain and a substitution of CGC bv CAC at codon 54 in another resistant strain.Conclusions In past five years,the resistance ratio of M tuberculosis was low in patients with cutaneous tuberculosis,and streptomycin resistance predominated in these strains.

Screening of High Daptomycin-producing Strain by He-Ne Laser Irradiation and Streptomycin Resistance Screening Method / 微生物学通报

The spores suspension of Streptomyces roseosporus D-38 irritated with 20mW He-Ne laser for 20 min were incubated on G1 medium plates containing 1. 9?g/mL of streptomycin. Ten percent of mutants increased the potency of daptomycin by streptomycin-resistance method, including the mutant LC-54, which could produce daptomycin 81. 2 mg/L, which was 39% higher than that of the beginning strain by flask fermentation.

STREPTOMYCIN RESISTANCE MUTATION——A STUDY ON THE BREEDING OF HIGH NATAMYCIN-PRODUCING STRAIN / 微生物学通报

A method of streptomycin resistance screening was applied to improve t he productivity of Natamycin by Streptomyces gilvosporeus(ATCC13326) The sp ores treated with UV light were regenerated on agar plates containing 0 6?g/mL stre p tomycin 122 streptomycin resistant(str) mutants were obtained The Natamycin y iel ds of 13 mutants were higher than the original strain The mutants with high Na t amycin productivity were screened at a high frequency(10 6%) The highest one that demonstrated 1 46 times that of the original strain in Natamy cin productivity was obtained

ACQUISITION OF STREPTOMYCIN-RESISTANT( STR )MUTANTS SCREENS HIGH-YIELD MEILINGMYCIN STRAIN IN STREPTOMYCES NANCHANGENSIS / 微生物学通报

After testing the resistance of Streptomycin to the strain NS-41-80 which is the Meilingmycin producer- Streptomyces nanchangensis , a lot of streptomycin-resistant ( str ) mutants were screened after the spores regenerated on the lethal media when they were treated with 4 different dosage of super-mutagent EMS. We have abtained the high-yield strain 80-5. 11-221 from these str mutants which only produces Meilingmycin and no Nanchangmycin in the rotation-flask experiments. The productivity of 80-5. 11-221 is 1521?g/mL 77. 9% higher than CK's 855?g/mL. After the shake flask fermentation experiment of 80-5. 11-221 for six generations, the productivity of F 2 and F 3 is stable and the productivity of F 4?F 5?F 6 decreases hastily with the increment of generations. It was showed that the chemical-resistance mutation of the strains had closely relation with yield mutation and the EMS dosage of the yield mutation was higher than the resistance-chemical mutation's through the statistical analysis between the dosage of mutation and the chemical-resistance mutational frequency?the variate capacity of the mutants' yield. A model of the resistance-chemical mutational labelling rational selection of the strain producing Meilingmycin was established.

A STUDY ON THE STREPTOMYCIN-RESISTANT (STR) MUTATIONAL SCREENING OF HIGH-YIELD NANCHANGMYCIN STRAIN / 微生物学通报

After testing the resistance of streptomycin to NS-41-80 Streptomyces Nanchangensis NS-41-80, the spores treated with 4 different dosage of super-mutagent EMS were regenerated on the lethal media, thus 3,000 streptomycin-resistant ( str ) str mutants were obtained. Then 202 spore mutants were screened through the pre-screening experiments and their yields are beyond 20% higher than the original strains respectively. In the re-screening experiments 48, 7 and 1 mutants were obtained whose yields are 100%, 200% and 300% higher than the original strains respectively and take the precentage of 23.76% and 1.60%, 3.46% and 0.23% and 0.5% and 0.03% of the number of the pre-screened strains and the rescreened strains respectively. Then 5 mutants were fermented whose yields are above 240% higher and the original strain through the continuous 3 batches fermentation, the yields are 57%～96.4% more than the original strains. Among them the yield of 80-5.3-165 is upwards of 6,000?g/mL and its norm is 5,855?g/mL. And a model of the streptomycin-resistance mutational screening of the strain producing Nanchangmycin was established.