Three new milbemycins from a genetically engineered strain S. avermitilis MHJ1011

Area of Science:

• Microbiology
• Organic Chemistry
• Pesticides

Background:

• Milbemycins are a class of macrocyclic lactones with known biological activities.
• Genetic engineering of Streptomyces avermitilis can lead to the production of novel compounds.
• Acaricidal compounds are crucial for managing agricultural and public health pests.

Purpose of the Study:

• To isolate and characterize new β-class milbemycins from a genetically modified Streptomyces avermitilis strain.
• To evaluate the acaricidal potential of the newly discovered compounds.

Main Methods:

• Cultivation of genetically engineered Streptomyces avermitilis MHJ1011.
• Isolation of compounds via fermentation broth.
• Structure elucidation using extensive spectroscopic analysis.
• Acaricidal activity assessment.

Main Results:

• Three new β-class milbemycins were successfully isolated: 13α-hydroxy-4-ethy1 milbemycin β3 (1), 13α-hydroxy-25-ethy1 milbemycin β3 (2), and 13α-hydroxy milbemycin β3 (3).
• Compound 1 exhibited particularly potent acaricidal activity.
• Structural analysis confirmed the novelty of the isolated compounds.

Conclusions:

• The genetic modification of Streptomyces avermitilis is an effective strategy for discovering novel milbemycins.
• The identified milbemycins, especially compound 1, represent promising candidates for developing new acaricides.
• Further research into the mechanism of action and efficacy of these compounds is warranted.