Fluctuation of alkaline phosphatase activity in synchronized heteroploid cell cultures: effects of prednisolone

In two heteroploid cell lines synchronized with thymidine double block, activity of alkaline phosphatase decreased during the 12 hour period preceding mitotic peak. A return to high values was observed during the next 12 hours of synchronous cycle. Prednisolone (11β, 17α, 21-trihydroxy-1,4-pregnadiene-3,20-dione), when added to such cell cultures increased alkaline phosphatase activity in one of the cell lines (Henle embryonic intestine) but had the opposite effect on another line (HeLa-S3) in which the enzyme activity was decreased. Neither effect could be demonstrated if the hormone was added at the end of S phase or if cells were arrested in metaphase by vinblastine sulfate.     

Lipid composition of cells and its variation during degradation of a culture of Streptococcus diacetilactis

The process of dying of a culture of Str. diacetilactis under conditions of prolonged culturing is accompanied by substantial changes in the composition of the cell lipids. In the lipids of young cells the basic components are mono- and diglucosyldiglycerides, as well as phospholipids--two glucophospholipids, cardiolipin, and phosphatidylglycerin; triglycerides and sterols are present in negligible amounts. As the Str. diacetilactis culture develops and undergoes degradation, an increase is observed in the total amount of extractable lipids. In this case the fraction of phospholipids increases (chiefly on account of cardiolipin), while the fraction of neutral glucolipids decreases. It was shown that in cell homogenates there is a negligible peroxidation of lipids, which is intensified as the culture dies off. There is a parallel acceleration of the uptake of O2 by cell suspensions from cultures of different ages. The detected changes in the lipids are correlated with the morphological and physiological indices of the state of the culture.     

Lipid composition of the secretion from human bronchial explant culture

In this study, we identified and quantitated the lipid components in the secretions of human bronchial explants cultured in a serum-free medium over a period of 50 days. Total lipids represented 6% of the dry material. This amount is considerably lower than that reported for 'normal' human sputum and suggests that the latter is contaminated by serum transudates, alveolar secretions, and microorganisms. Such serum-free culture systems are highly suitable to study cell physiology as it relates to human disease.     

Lipid composition of Zymomonas mobilis: effects of ethanol and glucose

Zymomonas mobilis is an alcohol-tolerant microorganism which is potentially useful for the commercial production of ethanol. This organism was found to contain cardiolipin, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine as major phospholipids. Vaccenic acid was the most abundant fatty acid, with lesser amounts of myristic, palmitic, and palmitoleic acids. No branched-chain or cyclopropane fatty acids were found. Previous studies in our laboratory have shown that ethanol induces the synthesis of phospholipids enriched in vaccenic acid in Escherichia coli (L. O. Ingram, J. Bacteriol. 125:670-678, 1976). The fatty acid composition of Z. mobilis, an obligately ethanol-producing microorganism, represents an extreme of the trend observed in E. coli. In Z. mobilis, vaccenic acid represents over 75% of the acyl chains in the polar membrane lipids. Glucose and ethanol had no major effect on the fatty acid composition of Z. mobilis. However, both glucose and ethanol caused a decrease in phosphatidylethanolamine and phosphatidylglycerol and an increase in cardiolipin and phosphatidylcholine. Ethanol also caused a dose-dependent reduction in the lipid-to-protein ratios of crude membranes. The lipid composition of Z. mobilis may represent an evolutionary adaptation for survival in the presence of ethanol.     

Lipid composition of yeastlike cells of the fungusPullularia pullulans

AlthoughPullularia pullulans is a polymorphic fungus, cultures have been obtained consisting exclusively of yeastlike cells. These cells can be considered as “medium lipid content” yeasts (5.7%). Thirty percent of the total lipids are phosphoglycerides, the most abundant of which are phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. The bulk of the nonpolar lipids is made up of unsaponifiable matter, sterols, and hydrocarbons. Eighteen fatty acid species have been detected, but the C₁₆ and C₁₈ species are by far the most abundant. The major unsaturated species is oleic acid. Linolenic acid is found in significant amounts only in triglycerides and esterified sterols. Fatty acid moieties associated with phosphatidylcholine and phosphatidylethanolamine are more unsaturated than those associated with phosphatidylserine or cardiolipin. Considerable proportions of the phosphoglycerides exist in the form of plasmalogen, which is unusual in yeasts.     

Lipid composition of tobacco cells cultivated at various temperatures

Tobacco cell suspensions were grown under controlled conditions to determine whether temperature aftected the fatty acid pattern of the cellular lipids. At any temperature ranging between 17° and 35°, the total fatty acid content and the levels of fatty acids or individual lipids varied during the growth period, The optimum temperature for lipid biosynthesis and polyunsaturated fatty acid accumulation was between 20° and 26°. Increase in the level of polyunsaturated fatty acids was associated with lower temperatures during the active cell division period.     

Changes in cation composition of aortic endothelial cells in culture

As a first step in the study of membrane transport characteristics of aortic endothelial cells the content of the two main cations, Na and K, was determined in cultured cells from bovine and porcine origins. The Na and K contents of cultured endothelial cells, dissociated by scraping or trypsin and collagenase treatment and subsequently separated through oil (25% dodecyl-, 75% dibutyl-phthalate), were more than 20-fold higher and five-fold lower, respectively, than those of undissociated cells. Based on daily determination of cell Na, K, and protein contents, the following findings were made. (1) Steady-state levels of Na and K were not reached in subconfluent, confluent or post-confluent monolayers. Instead, intracellular K content varied by up to two-fold, and intracellular Na by more than six-fold with marked 'peaks' after confluency. (2) Increasing the number of passages decreased cellular Na but not K content. (3) In cells cultured with 25 mM HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) the protein content was decreased by five-fold. (4) The K/Na ratio was dependent on the number of passages and buffers used and varied daily. (5) Cell Na decreased and K increased exponentially with the seeding density. These data not only reveal significant changes of ion transport parameters during manipulations of endothelial cell cultures, but moreover suggest unsynchronized development of ion transport systems and/or their intermittent activation and deactivation as reflected in the variations observed in cellular cation composition.     

Lipid composition of cyanidium

The major lipids in Cyanidium caldarium Geitler are monogalactosyl diglyceride, digalactosyl diglyceride, plant sulfolipid, lecithin, phosphatidyl glycerol, phosphatidyl inositol, and phosphatidyl ethanolamine. Fatty acid composition varies appreciably among the lipids, but the major ones are palmitic acid, oleic acid, linoleic acid, and moderate amounts of stearic acid. Trace amounts of other acids in the C₁₄ to C₂₀ range were also present. Moderate amounts of linolenic acid were found in two strains, but not in a third. The proportion of saturated acid is relatively high in all lipids ranging from about a third in monogalactosyl diglyceride to three-fourths in sulfolipid. This may be a result of the high growth temperature. Lipases forming lysosulfolipid, and lysophosphatidyl glycerol are active in ruptured cells; galactolipid is degraded with loss of both acyl residues. Thus the lipid and fatty acid composition of Cyanidium more closely resembles that of green algae than that of the blue-green algae, although there are differences of possible phylogenetic interest.     

Cytotoxic effects of phallolysin on a human heteroploid cell line

The effect of Phallolysin on cellular growth, macromolecular biosyntheses and cellular membrane structure was analysed using cells from the EUE line. Concentrations of the toxin that do not affect cellular growth, as determined by plating efficiency, have no effect on RNA or protein synthesis, but stimulate DNA synthesis. The doses of Phallolysin that inhibit cell survival do not affect macromolecular biosyntheses, but greatly increase the percentage of cells stainable with Trypan blue after 1 hour of incubation. At the same dose of the toxin the cells, analysed by electron microscopy, show increased vacuolization indicating an alteration of the membrane apparatus.