Physico-Chemical Interactions between Alcohol and Biological Membranes

Michaelis, Elias K.; Michaelis, Mary L.

doi:10.1007/978-1-4613-3626-6_4

Cited by 23 publications

(7 citation statements)

References 152 publications

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“…The influence of alcohols and growth temperatures on the membrane lipid bilayer has been studied extensively. Results of studies with model membranes (28), animal cell membranes (25), and bacterial membranes (11) provide overwhelming evidence that the addition of alcohols or changes in the growth temperature alter the membrane fluidity. This disrupts a variety of cellular functions by changing the physical properties of the membrane.…”

Section: Discussionmentioning

confidence: 99%

“…Analysis of cell membrane fluidity. Changes in the cell membrane state (lateral phase separation) were followed by using fluorescent depolarization (18,19,23,25,27,32,33). Cells were suspended in 6 ml of 0.1 M potassium citrate buffer to give a scattering optical density at 300 nm of 0.2. trans-Parinaric acid (0.5 mM; 9 pI) was added to 3 ml of sample, after which it was incubated for 30 min at the VOL.…”

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confidence: 99%

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Effect of Butanol Challenge and Temperature on Lipid Composition and Membrane Fluidity of Butanol-Tolerant Clostridium acetobutylicum

Baer

Blaschek

Smith

1987

Appl Environ Microbiol

208

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The effect of butanol challenge (0, 1.0, 1.5% [vol/vol]) and growth temperature (22, 37, 42°C) on the membrane composition and fluidity of Clostridium acetobutylicum ATCC 824 and a butanol-tolerant mutant, SA-2, was examined in chemically defined medium. Growth of strain ATCC 824 into the stationary phase coincided with a gradual increase in the percent saturated to percent unsaturated (SU) fatty acid ratio. When challenged with butanol at 22 and 37°C, ATCC 824 demonstrated an immediate (within 30 min) dose-response increase in the SU ratio. This strain showed little additional change over a 48-h fermentation. Compared with ATCC 824, growth of SA-2 into the late stationary phase at 22 or 37°C resulted in an overall greater increase in the SU ratio for both unchallenged and challenged cells. This effect was minimized when SA-2 was challenged at 42°C, probably due to the combination of the membrane fluidizing effect of butanol and the elevated temperature. Growth at 42°C resulted in an increase in longer acyl chain fatty acids at the expense of shorter acyl chains for both strains. The membrane fluidity exhibited by SA-2 remained essentially constant at various butanol challenge and temperature combinations, while that for the ATCC 824 strain increased with increasing butanol challenge. By synthesizing an increased amount of saturated fatty acids, the butanol-tolerant SA-2 strain has apparently developed a mechanism for maintaining a more stable membrane environment. Growth of the microorganism is necessary for butanol to fluidize the membrane. Incorporation of exogenous fatty acids (18:1) did not significantly improve the butanol tolerance of either strain. Since SA-2 was able to produce only trace amounts of either butanol or acetone, increased tolerance to butanol does not necessarily coincide with greater solvent yields in this strain.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Effect of Butanol Challenge and Temperature on Lipid Composition and Membrane Fluidity of Butanol-Tolerant Clostridium acetobutylicum

Baer

Blaschek

Smith

1987

Appl Environ Microbiol

208

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“…Several studies have indicated that ethanol decreases the degree of membrane organization, increases membrane leakage, and influences activities of membrane-associated proteins and transport systems (16,19). In ethanol-tolerant microorganisms, adaptation to ethanol stress involves an increase in the mean chain length of incorporated fatty acids, thereby thickening the hydrophobic membrane core.…”

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confidence: 99%

“…The total free-sterol content in S. cerevisiae also depended on the growth temperature when the yeast was grown under aerobic conditions in continuous culture (14). Adaptation of mammalian membranes to chronic ethanol feeding involved an increase in cholesterol content in several membrane types (19). Clearly, variation of hopanoid or sterol content is one of the mechanisms for regulation of membrane fluidity in response to changing culture conditions.…”

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confidence: 99%

Content and composition of hopanoids in Zymomonas mobilis under various growth conditions

1991

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By using a new method for quantification of the different hopanoid derivatives, a total hopanoid content of about 30 mg/g (dry cell weight) was observed in Zymomonas mobiis. This value is the highest reported for bacteria so far. The major hopanoids in Z. mobiis were the ether and glycosidic derivatives of tetrahydroxybacteriohopane, constituting about 41 and 49% of the total hopanoids. Tetrahydroxybacteriohopane itself, diplopterol, and hopene made up about 6, 3, and 1%, respectively. Only minor changes in hopanoid composition were observed with changes in growth conditions. Earlier reports on a correlation between hopanoid content and ethanol concentration in the medium could not be confirmed. Over a wide range of ethanol concentrations (5 to 60 g/liter), growth rates (0.08 to 0.25 h-1), and temperatures (25 to 37C), the molar ratio of hopanoids to phospholipids in the cells amounted to about 0.7. Only at growth rates of >0.30 h-1 did the molar ratio increase to about 1.The gram-negative, obligately fermentative bacterium Zymomonas mobilis is well-known for its high specific rates of ethanol production of up to 5 g of ethanol per g of dry cell weight per h. In continuous culture, Z. mobilis can accumulate up to 6% (wt/vol) ethanol, and in batch culture it can even accumulate up to 13%. Thus, its ethanol tolerance is remarkably high and comparable to that of yeasts (24).Several studies have indicated that ethanol decreases the degree of membrane organization, increases membrane leakage, and influences activities of membrane-associated proteins and transport systems (16,19). In ethanol-tolerant microorganisms, adaptation to ethanol stress involves an increase in the mean chain length of incorporated fatty acids, thereby thickening the hydrophobic membrane core. Often, the proportion of monounsaturated fatty acids (e.g., cisvaccenic acid) also increases (15). The extremely ethanoltolerant Lactobacillus homohiochii even incorporates over 97% unsaturated fatty acids in the membrane when growing in the presence of 10% (wt/vol) ethanol (15). Furthermore, sterols enhance the alcohol endurability of the cell membrane in yeasts, as was demonstrated with anaerobic cultures of Saccharomyces sake, which depended on supplementation with sterol ester to acquire ethanol tolerance (12).For Z. mobilis it was shown that more than 70% of the fatty acids in the phospholipid fraction is cis-vaccenic acid, which appears to be suitable for an ethanol-tolerant microorganism (7, 30). The most striking result, however, was the observation of considerable amounts of neutral hopanoids (6). Several different hopanoid derivatives were detected in Z. mobilis (10) (Fig. 1). Structural similarities to sterols, found in eukaryotic membranes, are apparent (20). Both classes of compounds are amphiphilic and have planar, rigid carbocyclic structures. Moreover, physicochemical studies on model membranes have shown that, like sterols, hopanoids influence membrane fluidity and stability (8,17,18).Recently a new method has been developed which enab...

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“…The majority of studies are either based on macroscopic ob servations or on functional parameters as sessed by histologic and cytologic methods. The effect of prostaglandins on a number of biochemical and physiological processes has been also observed, but the sequence of events by which prostaglandins mediate their protective action has not been estab lished nor has been the relation between enhanced physiological processes and the metabolic activity of the tissue compared and conclusively defined [9][10][11][12][13], Finally, the static interpretation of the data on alcohol and other damaging agents was attributed to the stipulation that prostaglandins evoke various forms of cellular protection [1,2], and the observed outcome of prostaglandin action might have evolved from the in fluence of the drug or its derivative upon transport and cellular metabolism [14][15][16].…”

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Prostaglandin Protection against Ethanol-Induced Gastric Injury: Regulatory Effect on the Mucus Glycoprotein Metabolism

Tsukada¹,

Zielénski²,

Mizuta³

et al. 1987

Digestion

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Effects of ethanol and prostaglandin on the metabolic processes of gastric mucosal cells have been evaluated by studying the biosynthesis and intra- and extracellular distribution of mucus glycoprotein. The rat gastric mucosal cell suspensions were subjected to a short-term tissue culture in the presence of 0–1.5 M ethanol and 0–100 ng/ml 16,16-dimethyl prostaglandin E₂ (DMPGE₂), using [³H]proline and [³H]palmitic acid as markers of mucin apoprotein synthesis and modification. Ethanol at concentrations of 0.02–0.1 M stimulated the glycoprotein synthesis, but the product was 2–3 times more extensively and rapidly degraded by pepsin than the glycoprotein synthesized in the absence of ethanol. Higher concentrations of ethanol (0.1–1.5 M) caused a marked reduction in the glycoprotein synthesis and a depletion of the intracellular mucus glycoprotein stores, and at 1.5 M ethanol the synthetic processes ceased to function. When the incubated tissue cultures were challenged with DMPGE₂, the highest synthetic and secretory stimulation was achieved at 10 ng/ml. The peptic susceptibility of the glycoprotein synthesized in the prostaglandin-enriched culture was somewhat lower than that of controls, and the proportion of the undegraded glycoprotein remaining after 22 h of digestion was significantly higher. Furthermore, the intracellular compartments were not depleted of mucus glycoprotein and the amount of the mucin apoprotein precursor increased to about 30%. Addition of DMPGE₂ prior to ethanol treatment resulted in the stabilization of cellular processes and the cells responded as if ethanol was not present in the medium. Moreover, the intracellular stores of mucus glycoprotein were not depleted and the secretory rate was moderately elevated. The regulatory effect of DMPGE₂ on the glycoprotein synthesis and distribution was significant, but diminished with increasing amounts of ethanol in the medium. The results suggest that DMPGE₂ imposes a stabilizing effect on the secretory processes and controls the mucus glycoprotein synthesis, but the extent of this protective action against ethanol is limited and depends upon the concentration of ethanol penetrating the mucosal cells.

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Physico-Chemical Interactions between Alcohol and Biological Membranes

Cited by 23 publications

References 152 publications

Effect of Butanol Challenge and Temperature on Lipid Composition and Membrane Fluidity of Butanol-Tolerant Clostridium acetobutylicum

Effect of Butanol Challenge and Temperature on Lipid Composition and Membrane Fluidity of Butanol-Tolerant Clostridium acetobutylicum

Content and composition of hopanoids in Zymomonas mobilis under various growth conditions

Prostaglandin Protection against Ethanol-Induced Gastric Injury: Regulatory Effect on the Mucus Glycoprotein Metabolism

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