Here we describe techniques that we developed for monitoring membrane fluidity of individual yeast cells during environmental adaptation and physiological changes. Multiphoton scanning fluorescence microscopy using laurdan as a membrane probe enables determination whether fluidity changes seen by spectroscopy reflect universal responses or changes only of sub-populations. Yeast membranes are a ...

The apparent wall slip (AWS) effect, accompanying the flow of colloidal dispersions in confined geometries, can be an important factor for the applications of nanofluids in heat transfer and microfluidics. In this study, a series of dilute TiO2 aqueous dispersions were prepared and tested for the possible presence of the AWS effect by means of a novel viscometric technique. The nanofluids, prep...

The purpose of this study was to investigate the effect of ultradeformable liposome components, Tween 20 and terpenes, on vesicle fluidity. The fluidity was evaluated by electron spin resonance spectroscopy using 5-doxyl stearic acid and 16-doxyl stearic acid as spin labels for phospholipid bilayer fluidity at the C5 atom of the acyl chain near the polar head group (hydrophilic region) and the ...

The role of docosahexaenoic acid (DHA) in the fluidity of the annular lipid regions and their associated membrane-bound proteins is still not as well understood as that in the global (bulk) lipid regions. We therefore studied the effects of dietary DHA on the relationship between annular and global lipid fluidity and membrane-bound enzymes such as 5'-nucleotidase and Mg(2)+-ATPase in the rat bi...

The human promyelocytic leukemia cell line. HL-60. undergoes differentiation in the presence of dimethyl sulfoxide (DMSO). phorbol esters, and other agents. Studies were undertaken to determine whether agents that promote differentiation influence membrane fluidity and to assess whether changes in membrane fluidity occur during the process of differentiation. Cells were grown in the presence of...

A proper regulation of membrane fluidity is critical for cellular activities such as communication between cells, mitosis, and endocytosis. Unsaturated lipids, a main component of biological membranes, are particularly susceptible to oxidative attack of reactive oxygen species. The oxidation of lipids can produce structural derangement of membranes and eventually alter the membrane fluidity. We...

The human promyelocytic leukemia cell line. HL-60. undergoes differentiation in the presence of dimethyl sulfoxide (DMSO). phorbol esters, and other agents. Studies were undertaken to determine whether agents that promote differentiation influence membrane fluidity and to assess whether changes in membrane fluidity occur during the process of differentiation. Cells were grown in the presence of...

Hemolysis of human or chicken erythrocytes by Sendai virus causes a change in the structure of the erythrocyte membrane lipid bilayer that can be detected by spin label electron spin resonance. In the intact erythrocyte, the phosphatidylcholine derivative spin label exists in a more rigid environment than the corresponding phosphatidylethanolamine label. Virus-induced hemolysis tends to abolish...

ANDREAS BALLOT*, LOTHAR KRIENITZ, KIPLAGAT KOTUT, CLAUDIA WIEGAND, JAMES S. METCALF, GEOFFREY A. CODD AND STEPHAN PFLUGMACHER LEIBNIZ-INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES, DEPARTMENT OF LIMNOLOGY OF STRATIFIED LAKES, ALTE FISCHERHÜTTE 2, D-16775 STECHLIN, GERMANY, KENYATTA UNIVERSITY, BOTANY DEPARTMENT, PO BOX 43844, NAIROBI, KENYA, 2 LEIBNIZ-INSTITUTE OF FRESHWATER ECOLOGY AND ...