What is "spiruchostatin"

Spiruchostatins are a group of chemical compounds isolated from Pseudomonas sp. as gene expression-enhancing substances. They possess novel bicyclic depsipeptides involving 4-amino-3-hydroxy-5-methylhexanoic acid and 4-amino-3-hydroxy-5-methylheptanoic acid residues. The two main forms are spiruchostatin A and spiruchostatin B.