Fatty acids adaptation membranes

Figure 11 Membrane reactor for the production of fatty acids. (Adapted from Ref. 31.)... 

Fig. 3. Scattergram of the correlation between the values of n (Hill coefficient) and the ratio double bond index per saturated fatty acids from membrane erythrocytes lipid. The equation of the regression line and overall correlation coefficient r with its significance are included A, (Na+, K+)-ATPase B, acetylcholinesterase C, (Mg2+)-ATPase D, (Ca2+, Mg2+)-ATPase. Diet supplements a, hydrogenated fat b, lard c, linseed oil d, olive oil e, fat-free f, corn oil and g, standard diet. (Adapted from Bloj et al., 1973a and Galo et al., 1975).

A molecular variation of plasma membrane has been reported by Puccia et al. Reduction of total lipids (XL) content and significant variations of triglyceride (TG) and phospholipids (PL) fractions were observed as a consequence of exposure of C. intestinalis ovaries to TBTCl solutions. In particular, an evident TG decrease and a PL increase were observed, which probably provoked an increment in membrane fluidity, because of the high concentration of long chain fatty acids and, as a consequence, PL. This could be a cell-adaptive standing mechanism toward the pollutants, as observed in Saccharomyces cerevisiae. Also the increase in the content of the polyunsaturated fatty acids (PUPA), important in the synthesis of compounds such as prostaglandin which are present in the ovary in a stress situation, was probably a consequence of a defense mechanism to the stress provoked by the presence of TBTCl. 

A shift in temperature from 38 to 22 °C leads to desaturation of fatty acids in Anabaena variabilis [110], resulting in control of the fluidity of the plasma membrane. Mutants have been isolated in Synechocystis PCC 6803 that were defective in desaturation of fatty acids, and the growth rate of one of these mutants was much lower than that of the wild-type at 22 °C [112]. It turned out that the mutant strain had a mutation in the gene desA, and when the wild-type allele was introduced into the chilling-sensitive cyanobacterium Anacystis nidulans, it resulted in increasing the tolerance of that strain to low temperature [113]. These experiments nicely demonstrate the existence of a mechanism of adaptation to low temperature in a chilling-tolerant cyanobacterium. 

Hartig C, N Loffhagen, H Harms (2005) Formation of trans fatty acids is not involved in growth-linked membrane adaptation of Pseudomonas putida. Appl Environ Microbiol 71 1915-1922. 

Rabinovich and Ripatti (1990) have shown that docosohexaenoic acid has conformational properties which keep its physico-chemical and, possibly, functional characteristics effective over a wide temperature range. This ensures the adaptation of cell membranes to changes of metabolic activity. Fluctuation in locomotory activity is one factor responsible for these changes. From their studies of the sea cucumber, Cucumaria frondatrix, Kostetsky et al. (1992) concluded that polyenoic acids of linolenic affinity did not exhibit a direct relatonship with temperature adaptation. In contrast to this, Zabelinsky et al. (1995) claim that C20 5o>3 (not C22 6a>3) and Cl8 1 are the fatty acids of key importance for temperature adaptation in marine fish. 

All these data provide evidence that, whenever an organism has to enhance its functional activity by compensatory means, the membranes alter their fatty acid composition. This points to the multifunctional role played by docosohexaenoic acid in a wide variety of adaptation processes it is an adaptogen , assisting the complicated processes which occur in cell membranes. 

Cossins, A.R., Friedlander, M.J. and Prosser, C.L. (1977). Correlations between behavioural temperature adaptations of goldfish and the viscosity and fatty acid composition of their synaptic membranes. Journal of Comparative Physiology 120, 109-121. 

Wodtke, E. (1978). Lipid adaptation in liver mitochondrial membranes of carp acclimated to different environmental temperatures. Phospholipid composition, fatty acid pattern and cholesterol content. Biochimica etBiophysicaActa 529,280-291. 

Zabelinsky, S.A., Chebotareva, M.A., Brovtsina, N.B. and Kravchenko, A.I. (1995). On the adaptive specialisation of fatty acid content and conformation condition in the membrane lipids of fish gills (In Russian). Zhumal Evolutsionnoy Biokhimii i Physiologii 31,29-36. 

Fatty acids facilitate the net transfer of protons from intermembrane space into the mitochondrial matrix, hence lowering the proton electrochemical potential gradient and mediating weak uncoupling. Uncoupling proteins generally facilitate the dissipation of the transmembrane electrochemical potentials of H+or Na+produced by the respiratory chain, and result in an increase in the H+and Na+permeability of the coupling membranes. They provide adaptive... 

In white winemaking, Saccharomyces cerevisiae must develop at low temperature, which reduces membrane fluidity. To maintain adequate fluidity in their membranes, yeasts increase the proportion of UFA in the phospholipids (Thurston et al. 1981 Torrija et al. 2003). Phospholipids with unsaturated fatty acids have a lower melting point and more flexibility than phospholipids with saturated acyl chains (Rodriguez et al. 2007). Such adaptation involves inducing the fatty acid desaturase OLEl which incorporate unsaturated bonds at defined positions in fatty acids (Nakagawa et al. 2002). 

Moreover, during alcoholic fermentation very important changes take place in the yeast s environment. Basically, the ethanol concentration increases progressively and yeasts need to adapt their plasmatic membranes to this aggressive new environment (Weber and Bont 1996). Apparently, the presence of ethanol in the medium alters drastically the fluidity of the membrane (Jones and Greenfield 1987). Under these conditions, Saccharomyces cerevisiae must increase its proportion of sterols and unsaturated fatty acids to compensate for this effect and consequently... 

Increased acid tolerance correlates strongly with a decrease in proton accumulation in the cytoplasm. This altered proton permeability is again associated with changes in the protein composition of the cell membranes. Acid-adapted E. coli changes the lipid composition of its membranes, and elevated levels of cyclopropane fatty acids are often found. This may mean that changes in the protein composition of the cell membrane are a result of changes in the membrane lipid composition. Both lipid and protein alterations may be necessary to protect a bacterial cell in acidic environments (Jordan, Oxford, and O Byrne, 1999). 

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