No abstract

An egg-membrane lysin was partially purified from the sperm extract of Tegula pjeifjeri. A turbidimetric and a chemical method with the use of isolated egg membrane as the substrate have been proposed for the quantitative assay of the lysin. The methods are shown to be valid over a limited range of lysin concentration.The pH optimum for the lytic activity is at about 8.3. The lysin shows considerable thermo-instability and is highly sensitive to PCMB and heavy metals. The reduction in turbidity of egg-membrane suspensions during lysis is accompanied by the release of a substance(s) containing neutral sugar.The possibility that the lytic process is composed of two steps is discussed.Two methods are routinely used t o evaluate the lytic activity of a sperm extract: one method is based on the calibration of the time required for complete disappearance of the egg membrane of the whole egg (TYLER, 1939) or of isolated egg membrane (BERG, 1950) and the other, more complicated but more sensitive, is the "indentation method", in which the number of indentations appearing on an egg membrane during lysis is counted at fixed intervals (KRAUSS, 1950). Although some properties of the lysin obtained from Mytilus o r Megathum sperm have been clarified by these methods, they are too qualitative t o serve as a tool for the quantitative characterization of a lysin or its mode of action.In a previous paper (HAINO and KIGAWA, 1966), we have reported a method for isolating the egg membrane from ovaries of Teguia pjeijyeri, and have also reported on chemical analyses which revealed that the egg membrane is composed of protein and sulfated mucopolysaccharide. During the course of these studies, two reaction processes were found t o provide methods for the quantitative assay of the lytic activity: (1) reduction of turbidity during lysis of a suspension of finely fragmented egg membranes; (2) liberation of some pro-203

Phage type of Staphylococcus aureus isolated from clinical sources. (-) •c•c Noplaque formation (on a plate seeded with the propagating strains).