alpha-Crystallin protein cognates in eggs of the moth, Plodia interpunctella: possible chaperones for the follicular epithelium yolk protein.

alpha-Crystallin protein cognates were found in germ cells of the Indianmeal moth, Plodia interpunctella (Shirk and Zimowska, 1997). A cDNA clone of 674 bp with a single open reading frame was isolated for a 25,000 molecular weight polypeptide member of this family, alpha CP25, and a single transcript of approximately 700 bp was found in the ovary of vitellogenic females. Both the DNA sequence and predicted amino acid sequence showed considerable homology with the embryonic lethal gene, l(2)efl, in Drosophila melanogaster.

Gramicidin S and dodecylamine induce leakage and fusion of membranes at micromolar concentrations.

The effect of the antibiotic gramicidin S and the synthetic cationic amphipath dodecylamine on membranes was studied with large unilamellar vesicles containing phosphatidylcholine and varying concentrations of cardiolipin. Fusion of vesicles composed of equal amounts of the two phospholipids occurred with both drugs at concentrations lower than 10 microM. Fusion was accompanied by leakage of the contents, while higher drug concentrations caused complete loss of vesicle contents.

Interaction of acidic liposomes with red blood cells. Induction of endocytosis and shedding of particles.

Calcium ions induced tight binding of massive amounts of liposomes containing cardiolipin, phosphatidyl-ethanolamine and phosphatidylcholine to erythrocytes. Initially, liposome-liposome fusion occurred and only subsequently the resulting large structures adhered to cells. Large clumps composed of liposomes and cells were formed.

Calcium-induced fusion of proteoliposomes and protein-free liposomes. Effect of their phosphatidylethanolamine content on the structure of fused vesicles.

The acidic phospholipid cardiolipin was shown to be very efficient in promoting calcium-induced fusion of proteoliposomes. The degree of fusion was dependent on the phosphatidylethanolamine content of the vesicles. Addition of CaCl2 to proteoliposomes containing phosphatidylcholine and cardiolipin but without phosphatidylethanolamine did not induce fusion.

Salt inactivation as a mechanistic probe of membrane-bound chloroplast coupling factor 1.

Conditions are reported under which ATP protects membrane-bound coupling factor 1 against sodium bromide inactivation. The presence of Mg2+ was found to be obligatory for this protection. ADP and GTP also protected the enzyme against salt inactivation but to a much smaller extent.