isolation, characterization and selection of avermectin-producing streptomyces avermitilis strains from soil samples

Isolation, Characterization and Selection of Avermectin-Producing Streptomyces avermitilis Strains From Soil Samples

BACKGROUND Streptomyces avermitilis, belonging to Actinomycetes, is specialized for production of avermectin, used as an anthelmintic and insecticidal agent. It is mostly found in soil and its isolation is very crucial for medically important avermectin production. OBJECTIVES In the present study, 10 bacterial isolates lacking antimicrobial activities were isolated from the soil samples colle...

Cloning and analysis of a DNA fragment stimulating avermectin production in various Streptomyces avermitilis strains.

To isolate a gene for stimulating avermectin production, a genomic library of Streptomyces avermitilis ATCC 31267 was constructed in Streptomyces lividans TK21 as the host strain. An 8.0-kb DNA fragment that significantly stimulated actinorhodin and undecylprodigiosin production was isolated. When wild-type S. avermitilis was transformed with the cloned fragment, avermectin production increased...

Engineered biosynthesis of milbemycins in the avermectin high-producing strain Streptomyces avermitilis

BACKGROUND Milbemycins, produced from Streptomyces hygroscopicus subsp. aureolacrimosus and Streptomyces bingchenggensis, are 16-membered macrolides that share structural similarity with avermectin produced from Streptomyces avermitilis. Milbemycins possess strong acaricidal, insecticidal, and anthelmintic activities but low toxicity. Due to the high commercial value of the milbemycins and incr...

Isolation and identification of bioactive compound producing Rhodococcus spp. isolated from soil samples

The genus Rhodococcus is gram positive bacterium which was classified into the family of Nocardiaceae.  The organism can be isolates from different sources, with capability to degrade diverse types of pollutant. Nowadays, scientists reported a few secondary metabolites which are produced by Rhodococci. Hence, the present study tried to isolate Rhodococci from different soil samples with the cap...

isolation and characterization of antibacterial producing actinomycetes from soil samples of fars province, iran

Construction of a single component producer from the wild type avermectin producer Streptomyces avermitilis.

Most microbial secondary metabolites are producec as complexes of closely related compoundsby theii producing organisms. The avermectins1*, milbemycins2 and nemadectins3~5) are typical examples produced ii such a manner. The milbemyciif complex is known t( consist of more than twenty components6 ~ 8), however only a few are commercial products. A rationale for thii phenomenon may be related to ...