Tiozzo E, Rocco G, Tossi A, Romeo D
Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Italy.
Biochem Biophys Res Commun. 1998 Aug 10;249(1):202-6. doi: 10.1006/bbrc.1998.9114.
PGYa and PGAa are synthetic, amphipathic, alpha-helical peptides that were designed using a novel "sequence template" approach. Their antimicrobial activity was tested against several pathogenic clinical isolates, most of which were multiply resistant to conventional antibiotics. PGYa appeared to be more active towards Gram-positive species (MIC = 0.5-4 microM), towards such Gram negative species as P. aeruginosa, X. maltophilia, E. coli, K. pneumoniae and S. enteritidis (MIC = 1.4 microM), and towards the filamentous fungus A. niger (MIC = 8 microM). Conversely, PGAa showed the greater activity towards three Candida species (MIC = 2.16 microM). The peptides were shown to have a bactericidal activity, resulting in a decrease of viability for both Gram-positive and -negative bacteria of 3-6 logs within 60 min. Scanning electron microscopy of S. aureus and E. coli treated with PGYa shows considerable roughening and blebbing of the bacterial surfaces providing conclusive evidence that the peptide is membrane active.
PGYa和PGAa是合成的两亲性α-螺旋肽，采用一种新颖的“序列模板”方法设计而成。它们的抗菌活性针对几种致病性临床分离株进行了测试，其中大多数对传统抗生素具有多重耐药性。PGYa对革兰氏阳性菌（MIC = 0.5 - 4微摩尔）、对铜绿假单胞菌、嗜麦芽窄食单胞菌、大肠杆菌、肺炎克雷伯菌和肠炎沙门氏菌等革兰氏阴性菌（MIC = 1.4微摩尔）以及对丝状真菌黑曲霉（MIC = 8微摩尔）似乎更具活性。相反，PGAa对三种念珠菌属（MIC = 2.16微摩尔）表现出更大的活性。这些肽显示出杀菌活性，导致革兰氏阳性菌和阴性菌的活力在60分钟内下降3 - 6个对数。用PGYa处理的金黄色葡萄球菌和大肠杆菌的扫描电子显微镜显示细菌表面有相当程度的粗糙化和起泡，这提供了肽具有膜活性的确凿证据。
