Search

The volatile oil extracted from Zanthoxylum rhoifolium Lam (Rutaceae) leaves was tested to verify its antimicrobial activity efficacy against six types of different high-virulent Gram-negative bacteria isolated from clinical material and against three different types of fungi (two yeast and a filamentous one). Some results were different from those observed in the literature, and these differences might have occurred due to seasonal, geographic, or nutritional variations of the plants. Nevertheless, the volatile oil was found to be very efficient against Salmonella enteritidis and Shigella sonnei, bacteria responsible for diarrhea and for a huge number of deaths. Regarding the fungi, a great capacity of the volatile oil in inhibiting the growth of Aspergillus flavus was found, although it does not affect Candida tropicalis and Candida guilliermondii growth. [ABSTRACT FROM AUTHOR]

Snake venom-secreted phospholipase A 2 (svPLA 2 ) enzymes, both catalytically active and inactive, are a central component in envenoming. These are responsible for disrupting the cell membrane's integrity, inducing a wide range of pharmacological effects, such as the necrosis of the bitten limb, cardiorespiratory arrest, edema, and anticoagulation. Although extensively characterized, the reaction mechanisms of enzymatic svPLA 2 are still to be thoroughly understood. This review presents and analyses the most plausible reaction mechanisms for svPLA 2, such as the "single-water mechanism" or the "assisted-water mechanism" initially proposed for the homologous human PLA 2 . All of the mechanistic possibilities are characterized by a highly conserved Asp/His/water triad and a Ca 2+ cofactor. The extraordinary increase in activity induced by binding to a lipid-water interface, known as "interfacial activation," critical for the PLA 2 s activity, is also discussed. Finally, a potential catalytic mechanism for the postulated noncatalytic PLA 2 -like proteins is anticipated.