sentence: Park et al. [ 17 ] studied the substrate specificity of the AHL-acylase AhlM from Streptomyces sp. M664 , which effectively degraded C8-HSL , C10-HSL and 3-oxo-C12-HSL with different acyl chain substitutions but exhibited relatively low activity on short-acyl-chain AHLs , such as C6-HSL and 3-oxo-C6-HSL , and did not degrade detectable amounts of C4-HSL .