Streptomyces Olivoreticuli Research Articles

Characterization and biocontrol mechanism of Streptomyces olivoreticuli as a potential biocontrol agent against Rhizoctonia solani

Rhizoctonia solani is a widespread and devastating plant pathogenic fungus that infects many important crops. This pathogen causes tobacco target spot, a disease that is widespread in many tobacco-growing countries and is destructive to tobacco. To identify antagonistic microorganisms with biocontrol potential against this disease, we isolated Streptomyces strains from forest inter-root soil and screened a promising biocontrol strain, ZZ-21. Based on in vitro antagonism assays, ZZ-21 showed a significant inhibitory effect on R. solani and various other phytopathogens. ZZ-21 was identified as Streptomyces olivoreticuli by its phenotypic, genetic, physiological and biochemical properties. Complete genome sequencing revealed that ZZ-21 harbored numerous antimicrobial biosynthesis gene clusters. ZZ-21 significantly reduced the lesion length in detached inoculated leaf assays and reduced the disease index under greenhouse and field conditions. Based on an in vitro antagonistic assay of ZZ-21 culture, the strain exhibited an antifungal activity against R. solani in a dose-dependent manner. The culture filtrate could impair membrane integrity, possibly through membrane lipid peroxidation. ZZ-21 could secrete multiple extracellular enzymes and siderophores. According to a series of antifungal assays, the extracellular metabolites of ZZ-21 contained antimicrobial bioactive compounds composed of proteins/peptides extracted using ammonium sulfate precipitation, which were stable under stress caused by high temperature and protease K. The EC50 value for ammonium sulfate precipitation was determined to be 21.11 μg/mL in this study. Moreover, the proteins/peptides also exhibited biocontrol ability and were observed to alter the plasma membrane integrity of R. solani which were evaluated by biocontrol efficacy assays on detached tobacco leaves and PI staining. Overall, strain ZZ-21 shows the potential to be developed into a biopesticide against tobacco target spot disease.

PHYLOGENETIC ANALYSIS AND ANTI MICROBIAL ACTIVITY OF Streptomyces spp. ISOLATED FROM COMPOST SOIL IN SURABAYA INDONESIA ON THE BASIS OF 16S Rrna GENE

Eight isolates of Streptomyces sp. can be isolated from compost soil in Surabaya, Indonesia. The results of biochemical and morphological tests showed that the 8 isolates were new. Phylogenetic analysis was performed on the sequence of 16S rRNA gene. Nucleotide sequences of 16S rRNA gene Streptomyces sp. the compost soil isolates of Surabaya were analyzed and compared with the 16S rRNA gene sequence from the literature. Streptomyces sp. the compost soil of Surabaya based on the 16S rRNA gene showed the new species of Streptomyces. The result of phylogenetic tree diagram showed that Streptomyces Sp-D, Sp-Ep, Sp-G and Sp-I found in Bratang Surabaya compost house land were new isolates. Streptomyces Sp-Ep was a new type of Streptomyces closely related to Streptomyces indonesiasis and Streptomyces nashvillensis. Streptomyces Sp-Ea was Streptomyces olivoreticuli which was still related to Streptomyces yogyakartensis. Streptomyces Sp-F was Streptomyces levis strain NRRL B-24299. Streptomyces Sp-C was Streptomyces filamentosus. Streptomyces Sp-D was a new type of Streptomyces closely related to Streptomyces javensis and Streptomyces roseus. Streptomyces Sp-G was a new type of Streptomyces closely related to Streptomyces roseoviridis strain NBRC 12911 and Streptomyces thermocarboxydovorans strain AT52. Streptomyces Sp-I was a new streptomyces that was still closely related to Streptomyces cangkringensis and Streptomyces asiaticus. Streptomyces Sp-A was Streptomyces laurentii strain: LMG 19959.

A new group of antibiotics, hydroxamic acid antimycotic antibiotics. II. The structure of neoenactins NL1 and NL2 and structure-activity relationship.

The structures of neoenactins (NEs) NL1 and NL2, novel antimycotic antibiotics produced by Streptoverticillium olivoreticuli in a precursor-oriented fashion, were elucidated by 1H and 13C NMR and mass spectroscopic studies. The structures of both antibiotics are closely related to that of NE-A, the major component of NE congeners, being classified in the group of hydroxamic acid antimycotic antibiotics in which L-serine and a diketo amine form a hydroxamic acid structure. To study the role of the carbonyl groups in the biological activities of the hydroxamic acid antimycotic antibiotics, NE-A was modified by reaction with various carbonyl reagents. In terms of antimycotic activity, the derivatives are classified into two distinct groups; the first ones are fairly comparable to but not exceeding and the second ones are less active than NE-A depending on their tendency to revert to NE-A by hydrolysis. In general, the biological activities of the derivatives are inversely proportional to their stabilities to hydrolysis.

Isolation and structure of 26‐deoxylaidlomycin, a new polyether antibiotic from Streptoverticillium olivoreticuli

Abstract26‐Deoxylaidlomycin (I, C37H61O11Na) was isolated together with its cometabolite laidlomycin (II) from the mycelium of Streptoverticillium olivoreticuli IMET 43782. Its structure was determined by high‐field 13C and 1H NMR, and MS spectral studies. The antibacterial activity of I against Bacillus subtilis ATCC 6633 was found to be approx. four times higher than that of laidlomycin (II).CALLING STATEMENT : magnified image.The structure of 26‐deoxylaidlomycin (I: sodium salt, R1 = Na, R2 = H): III free acid: R1, R2 = H and laidlomycin (II, sodium salt: R1 = Na; R2 = OH).

A new group of antibiotics, hydroxamic acid antimycotic antibiotics. I. Precursor-initiated changes in productivity and biosynthesis of neoenactins NL1 and NL2.

Neoenactins (NEs) are L-serine-containing antifungal antibiotics produced by Streptoverticillium olivoreticuli. The effect of supplementation of individual amino acids on the production of NEs by this organism was examined from both quantitative and qualitative view points by using a nitrogen source-restricted medium. L-Alanine, L-arginine, L-glutamine, L-histidine, L-lysine and L-proline increased significantly the total productivity of NEs without changing the production ratio of the congeners. The supplementation of L-norvaline, L-isoleucine, L-leucine and L-valine to the culture medium resulted in selective enhancement of the production of NEs A, B1, B2, and M1, respectively, while significant change was not observed in terms of overall production of NEs. When L-norleucine was employed as an amino acid supplement, new NE congeners, named NEs NL1 and NL2, were preferentially produced; but the amount of NEs produced was not markedly affected.

Des-O-methylolivoretin C is a new member of the teleocidin class of tumor promoters.

Des-O-methylolivoretin C, a demethylated form of olivoretin C, is a naturally occurring compound in Streptomyces mediocidicus and Streptoverticillium olivoreticuli. Des-O-methylolivoretin C is a regioisomer of teleocidin B, which has the same activity as teleocidin. The tumor-promoting activity of des-O-methylolivoretin C was studied in a two-stage carcinogenesis experiment on mouse skin in comparison with that of teleocidin. Treatments with 7,12-dimethylbenz[a]anthracene (DMBA) plus des-O-methylolivoretin C and DMBA plus teleocidin induced tumors in 63.3% and 84.6% of the mice, respectively, in week 30. The difference in the tumor-promoting activities of des-O-methylolivoretin C and teleocidin is presumably related to the regioisomeric difference in the cyclohexene ring.

Isolation, characterization and synthesis of pimprinine, pimprinethine and pimprinaphine, metabolites of Streptoverticillium olivoreticuli.

Isolation, characterization and synthesis of pimprinine, pimprinethine and pimprinaphine, metabolites of Streptoverticillium olivoreticuli.