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The fluidity of Synechocystis membranes was adjusted in vivo by temperature acclimation, addition of fluidizer agent benzyl alcohol, or catalytic lipid hydrogenation specific to plasma membranes. The reduced membrane physical order in thylakoids obtained by either downshifting growth temperature or administration of benzyl alcohol was paralleled with(More)
Membranes provide the structural framework that divides cells from their environment and that, in eukaryotic cells, permits compartmentation. They are not simply passive barriers that are liable to be damaged during environmental challenge or pathological states, but are involved in cellular responses and in modulating intracellular signalling. Recent data(More)
Preservation of the chemical architecture of a cell or of an organism under changing and perhaps stressful conditions is termed homeostasis. An integral feature of homeostasis is the rapid expression of genes whose products are specifically dedicated to protect cellular functions against stress. One of the best known mechanisms protecting cells from various(More)
A single-copy gene resembling the gene for the delta9 acyl-lipid desaturase (desC) was cloned from the thermophilic cyanobacterium Synechococcus vulcanus. Expression of desC in Escherichia coli confirmed that it encodes the delta9 desaturase. The nucleotide sequence of the desC was characterized by high G+C content that is typical of the sequences of(More)
Addition of a saturated fatty acid (SFA) induced a strong increase in heat shock (HS) mRNA transcription when cells were heat-shocked at 37 degrees C, whereas treatment with an unsaturated fatty acid (UFA) reduced or eliminated the level of HS gene transcription at 37 degrees C. Transcription of the delta 9-desaturase gene (Ole1) of Histoplasma capsulatum,(More)
In addition to high temperature, other stresses and clinical conditions such as cancer and diabetes can lead to the alteration of heat-shock protein (HSP) levels in cells. Moreover, HSPs can associate with either specific lipids or with areas of special membrane topology (such as lipid rafts), and changes in the physical state of cellular membranes can(More)
The novel hydroxylamine derivative, bimoclomol, has been shown previously to act as a co-inducer of several heat shock proteins (Hsp-s), enhancing the amount of these proteins produced following a heat shock compared to heat shock alone. Here we show that the co-inducing effect of bimoclomol on Hsp expression is mediated via the prolonged activation of the(More)
The concentrations of two structurally distinct membrane fluidizers, the local anesthetic benzyl alcohol (BA) and heptanol (HE), were used at concentrations so that their addition to K562 cells caused identical increases in the level of plasma membrane fluidity as tested by 1,6-diphenyl-1,3,5-hexatriene (DPH) anisotropy. The level of membrane fluidization(More)
One of the well-characterized phenomena associated with the acclimation of organisms to changes in ambient temperature is the regulation of the molecular motion or "fluidity" of membrane lipids via changes in the extent of unsaturation of the fatty acids of membrane lipids. The enzymes responsible for this process when the temperature is decreased are the(More)
During heat shock, structural changes in proteins and membranes may lead to cell death. While GroE and other chaperone proteins are involved in the prevention of stress-induced protein aggregation and in the recovery of protein structures, a mechanism for short-term membrane stabilization during stress remains to be established. We found that GroEL(More)