These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Purification, characterization and bactericidal activities of basic phospholipase A2 from the venom of Agkistrodon halys (Chinese pallas).
    Author: Perumal Samy R, Gopalakrishnakone P, Ho B, Chow VT.
    Journal: Biochimie; 2008 Sep; 90(9):1372-88. PubMed ID: 18472013.
    Abstract:
    Agkistrodon snake venoms contain a variety of phospholipases (PLA2), some of which are myotoxic. In this study, we used reverse-phase HPLC to purify PLA2 from the venom of Agkistrodon halys. The enzyme named as AgkTx-II, a basic Asp49 PLA2, has a molecular masses of 13,869.05. The amino acid sequence and molecular mass of AgkTx-II was identical to those of an Asp49 basic myotoxic PLA2 previously isolated from this venom. Antibacterial activities were tested by susceptibility and broth-dilution assays. AgkTx-II exerted a potent antibacterial activity against Staphylococcus aureus, Proteus vulgaris, Proteus mirabilis, and Burkholderia pseudomallei. The MIC values of AgkTx-II ranged between 85 and 2.76microM and was most effective against S. aureus, P. vulgaris, P. mirabilis (MIC of 21.25microM) and B. pseudomallei (MIC of 10.25microM). This AgkTx-II rapidly killed S. aureus, P. vulgaris and B. pseudomallei in a dose-dependent manner. The effect of the AgkTx-II on bacterial membranes was evaluated by scanning and transmission electron microscopy. AgkTx-II caused morphological alterations apparent on their cellular surfaces, suggesting a killing mechanism based on membrane permeabilization and damage. Cytotoxicity was measured by XTT tetrazolium (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) and lactate dehydrogenase (LDH) assays using U-937 cells (monocytes). The AgkTx-II did not affect cell viability up to 500microM concentrations but cell death was evident at 1000microM concentration after 24 and 48h. Furthermore, the repeated exposure of AgkTx-II (2-14microM) treated mice showed different tissue alterations, mainly at the brain and kidney; the toxicological potential of AgkTx-II remains to be elucidated. The AgkTx-II exhibits no hemolytic action even at high doses (10-100microM) in human erythrocytes. However, the AgkTx-II is believed to exert its bactericidal effect by permeabilizing the bacterial membrane by forming pores. In addition, the basic PLA2 AgkTx-II displays a bactericidal effect, which may be either dependent or independent of catalysis.
    [Abstract] [Full Text] [Related] [New Search]