Effect of the phase state of lipids on their interaction with cobra cytotoxin

Interaction between cytotoxin of the Central Asia cobra venom and dimiristoylphosphatidylcholine bilayer depending on its phase state was studied by ESR with spin label. A conclusion can be drawn that the efficiency of cytotoxin effect on the membranes depends on their phase state. Cytotoxin molecules are incorporated into myophile region of the bilayer, only if the latter is in the liquid crystal state. The interaction between cytotoxins and lipids of the bilayer in a gel state is in the main conditioned by electrostatic forces.     

The Biological Clock in Chlamydomonas reinhardi

SYNOPSIS. Chlamydomonas reinhardi has a biological clock regulating phototaxis in dividing and non-dividing cultures; it also can exert some control on growth of continuous cultures. The period length is ∼ 24 hr; it is temperature-compensated and not dependent on the average growth rate. The rhythm can be entrained or phased by light-dark conditions. In dividing cultures a periodic fluctuation in cell number and total protein persists in continuous light.     

Mordanting Plant Tissues

Selected current ideas on the mordanting of plant tissues are presented in the hope that they will be of practical assistance, especially to the beginner. The nature of the mordanting process and the results which may be expected following mordanting are briefly described. Specific technics are presented for the mordanting of natural dyes, synthetic dyes generally, the basic synthetic dyes and the acid synthetic dyes.