Milbemycin

The milbemycins are a group of macrolides chemically related to the avermectins and were first isolated in 1972 from Streptomyces hygroscopicus.

[2] Milbemycins have a similar mechanism of action, but a longer half-life than the avermectins.

They open glutamate-sensitive chloride channels in neurons and myocytes of invertebrates, leading to hyperpolarisation of these cells and blocking of signal transfer.

A grand total of five species, namely S. hygroscopicus, S. griseochromogenes, S. cyaneogriseus, S. nanchanggensis and S. bingchenggensis, are known to produce this family of compounds.

[4] An alternative pathway to higher yields was demonstrated in 2017, when select genes from S. avermitilis were swapped out so the avermectin producer makes milbemycin instead.