Figure 1

Permeabilizing potency of neuropeptides against E.coli ML-35p, determined by β-galactosidase assay with ONPG as its substrate. Bacteria at 10⁶ CFU/ml were incubated at 37°C for 90 min in the presence of the indicated micromolar concentrations of neuropeptides: neuropeptide Y (NPY), fragment of neuropeptide Y (NPYf = NPY_18–36), calcitonin gene related peptide (CGRP), substance P (SP), and somatostatin (SOM). In negative controls, bacteria incubated in neuropeptide-free NAPB containing 1/100 of TSB showed no net hydrolysis of ONPG. Polymyxin B (PMB) at 1 μg/ml was included as a positive control. The representative curves of at least three independent experiments are presented.