Isolation of the antibacterial substance from the mucus of the Philippine land snails.

A glycoprotein isolated from the mucus secretion of African giant snails Achatina fulica Ferussac recently captured in Okinawa, Japan, was found to have activity against Gram positive and Gram negative bacteria. Based on these studies, the mucus secretion of three land snails belonging to Sub-Class Pulmonata, Order Stylommatophora-Achatina fulica, Cochlostyla metafomis, and Cochlostyla metaformis ovularis were studied. The objective is to be able to isolate components with similar activity. The snails were gathered from Silang, Cavite, kept alive in the laboratory, and fed with vegetables. Mucus secretion was enhanced by stimulating the collar of the snail with a spatula. Qualitative analysis shows that the crude mucus samples were a mixture of glycoproteins with an isoelectric pH between 4-5. The water-soluble fraction was extracted using Tris-HCl buffer (pH = 8.0) and precipitated using 50 percent and 90 percent ammonium sulfate saturation. Each fraction was tested for activity against Staphyloccocus aureus and Escherichia coli. Quantitative analysis on each fraction was done using Anthrone-Sulfuric Acid Method and UV absorption of proteins at 280 nm. The electrophoretic patterns were compared using sodium dodecylsulfate polyacrylamide gel electrophoresis. Differences in the electrophoretic patterns account for the differences in antimicrobial activities. Gel filtration chromatography was done to further purify the samples and to determine the molecular weight of each fraction