| Title | Antibacterial activity of six novel peptides from tityus discrepans scorpion venom. A fluorescent probe study of microbial membrane na+permeability changes. | | Author(s) | Licencee PD, D'Suze G, Salazar V, Sevcik C, Shannon JD, Sherman N, Fox JW | | Institution | University of Virginia, Laboratory on Cellular Neuropharmacology, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, Panamericana, Caracas 1020-A, Venezuela, Bolivarian Republic of. | | Source | Toxicon 2009 Jun 18. | | Abstract | Six novel peptides (named bactridines) were isolated from Tityus discrepans scorpion venom. From mass spectrometry molecular masses were 6916, 7362, 7226, 7011, 7101 and 7173 Da (bactridines 1 to 6). Bactridines 1 and 2 were sequenced by Edman degradation. The sequences and in silico analysis, indicated that they are positively charged polypeptides comprised of 61 and 64 amino acids (AA), respectively, bactridine 1 and bactridine 2 containing 4 disulfide bridges. Bactridine 1 was only toxic to cockroaches and bactridine 2 to 6 were only toxic to mice.Bactridine 1 has a 78% sequence identity with ardiscretin, an insect specific sodium current blocker. Measured as the minimal inhibitory concentration, bactridines had high antibacterial activity against a wide range of Gram positive and Gram negative bacteria. Complete bacterial growth inhibition occurred at concentrations from 20 to 80 uM depending on the bacteria and peptide tested. E ffects on membrane Na+ permeability induced by bactridines were observed on Yersinia enterocolitica loaded with 1 uM CoroNaTM Red. CoroNaTM Red fluorescence leakage from bacteria was observed after exposure to 0.3 uM of any bactridine tested, indicating that they modified Na+ membrane permeability. This effect was blocked by 10 uM amiloride and by 25 uM ibefradil drugs that aff ct Na+ and Ca+2 channels respectively. We found no evidence of changes of K+ or Ca+2 concentrations neiter inside nor outside the bacteria in experiments using the fluorescent dyes Fluo 4AM (10 uM) and PBFI (20 uM). | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19540868 |
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