Showing papers on "Growth medium published in 1982"

Effect of cellular fatty acid alteration on adriamycin sensitivity in cultured L1210 murine leukemia cells.

Abstract: We have investigated the effect of cellular fatty acid alteration on Adriamycin cytotoxicity using the L1210 lymphoblastic leukemia cell line. Cells growing in Roswell Park Memorial Institute Medium 1640 with 5% fetal bovine serum were modified with respect to fatty acid composition by supplementing their growth medium with 32 microM docosahexaenoic acid (22:6) or oleic acid (18:1). A soft agar clonogenic assay was then used to assess survival following incubation with Adriamycin. When exposed to the drug at a concentration of 0.4 microM, cells grown in the 22:6-supplemented medium were more sensitive (min of drug treatment required to reduce survival by 63% on the exponential portion of the survival curve, 64.9 +/- 4.2 min) to the cytotoxic effects of Adriamycin than cells grown in unsupplemented medium (min of drug treatment required to reduce survival by 63% on the exponential part of the survival curve, 106 +/- 9.7 min) (p less than 0.005). Cytotoxicity of L1210 cells grown in 18:1-supplemented medium was similar to that of cells grown in unsupplemented medium (min of drug treatment required to reduce survival by 63% on the exponential part of the survival curve, 126.6 +/- 9.1 min). The heightened sensitivity to Adriamycin of cells whose medium contained 22:6 increased as the concentration of fatty acid used to supplement the growth medium was increased. The cytotoxicity was also a function of the concentration of Adriamycin from 0.1 to 1.6 microM. When compared to cells grown in unsupplemented medium, those grown in 22:6-supplemented medium contained 3- to 4-fold more polyunsaturated fatty acids in their phospholipids, with a resultant doubling in the mean number of double bonds per fatty acid molecule. These data demonstrate that modification of cellular fatty acid composition may dramatically affect the sensitivity of a tumor cell to Adriamycin.

Glutamine and proline accumulation by Staphylococcus aureus with reduction in water activity.

Abstract: Proline and glutamine were found to be the predominant free amino acids in Staphylococcus aureus MF-31 challenged by 58 or 10% NaCl in the growth medium The accumulation of glutamine was the result of its synthesis, whereas the accumulation of proline was by transport

The production of plant cell wall polysaccharide‐degrading enzymes by hemicellulolytic rumen bacterial isolates grown on a range of carbohydrate substrates

Abstract: Several cultures of bacteria, isolated from the rumen, that were able to utilize plant cell wall structural polysaccharides were grown on a range of carbohydrate substrates and the activities of the principal polysaccharide-degrading enzymes determined. The esterase activity was also monitored. The extent of hemicellulose degradation and utilization by the isolates was comparable with that of the hemicellulolytic type strains. Enzyme activities in all of the cultures examined were affected by the carbon source in the growth medium. Many responses were strain specific, although growth on glucose (or cellobiose and maltose to a lesser extent) resulted in reduced activities in most of the organisms examined, whilst polysaccharidic substrates resulted in higher levels of the appropriate polysaccharidase. However, enzyme activity was detectable in some isolates after culture on mono- or disaccharides in the absence of the principal or related polysaccharide substrate.

The effect of the carbohydrate growth substrate on the glycosidase activity of hemicellulose‐degrading rumen bacterial isolates

Abstract: Thirteen strains of hemicellulose-degrading bacteria isolated from the rumen were grown on ten different monosaccharide, disaccharide and hemicellulosic poly-saccharide substrates in vitro, and the range and specific activities of the glycosidase enzymes formed were determined. Alkaline phosphatase activities were also measured. The specific activities were affected by the carbohydrate source supplied in the growth medium and were usually reduced in glucose grown cells, and less frequently following growth on cellobiose; the responses to other substrates were both enzyme and organism dependent. In several of the strains examined many of the enzymes were found following growth on all of the substrates tested, although there were wide variations in the specific activities. The activities of several of the glycosidases were increased after growth on hemicellulosic polysaccharides.

Effect of sodium chloride on bakers' yeast growing in gelatin.

Abstract: In recent years, industrial fermentation researchers have shifted their attention from liquid to solid and semisolid culture conditions. We converted liquid cultures to the semisolid mode by adding high levels of gelatin. Previous studies on liquid cultures have revealed the inhibitory activity of mineral salts, such as NaCl, on the fermentation of sugars by yeasts. We made a kinetic study of the effects of 1 to 5% (wt/vol) NaCl on the alcoholic fermentations of glucose by Saccharomyces cerevisiae in a growth medium containing 16% gelatin. Our results showed that the effect of high salt content on semisolid culture is essentially the same as the effect on liquid culture; i.e., as the salt content increased, the following occurred: (i) the growth of yeasts decreased, (ii) the lag period of the yeast biomass curve lengthened, (iii) the sugar intake was lowered, (iv) the yield of ethanol was reduced, and (v) the production of glycerol was increased. We observed a new relationship correlating the area of kinetic hysteresis with ethanol production rate, acetaldehyde concentration, and the initial NaCl concentration.

Preparation of low calcium growth medium suitable for determination of tumorigenicity of cultured cells

Abstract: A simplified method for preparation of calcium-deficient growth medium without the use of EGTA is provided The medium may be used for assessing tumorigenicity of cultured cells

Derepression of an NAD-linked dehydrogenase that serves an Escherichia coli mutant for growth on glycerol.

Abstract: An Escherichia coli mutant using an NAD-linked dehydrogenase instead of an ATP-dependent kinase as the first enzyme for glycerol dissimilation excreted dihydroxyacetone during the initial phase of growth. The intermediate was salvaged as growth of the culture advanced. The transient loss of the intermediate into the medium appeared to be partly determined by variation of the level of glycerol dehydrogenase with growth conditions. With up to 2% casein hydrolysate as the carbon and energy source, the cellular level of the dehydrogenase increased 1 order of magnitude at the end of growth. This increase was probably caused by the depletion of certain metabolites and was prevented by the addition of pyruvate or glucose to the growth medium. The repressive effect of these compounds was not lifted by the addition of cyclic AMP. Diminution of oxygen tension in the culture medium with increased cell density was not directly responsible for the increase of the enzyme level. Thus, neither catabolite repression nor respiratory repression was implicated as an important control mechanism in the synthesis of this enzyme. Since increases in the specific activity of the enzyme in cell extracts reflected increases in the concentration of the enzyme protein, post-translational control was also not involved. A novel kind of regulation of gene expression is indicated.

Influence of growth conditions on the composition of the plasma membrane from yeast and on kinetic properties of two membrane functions.

Abstract: The influence of different growth conditions on the phospholipid composition and on two membrane functions, the Mg-ATPase and the purine transport system, was investigated. Addition of cholinechloride to the growth medium led to a certain rise in the amount of phosphatidylcholine, whereas supplementation with ethanolamine resulted in a considerably higher portion of phosphatidylethanolamine. When yeast cells were cultured at lower temperatures we found more short-chain fatty acids with a higher content of monounsaturated chains as compared to higher growth temperatures. Addition of paraquat, a herbicide which enhances lipid peroxidation by free radicals, reduced the amount of unsaturated fatty acids without influencing their chain length. The altered membrane composition had no influence on the basic mechanism of interaction between ATPase, MgATP, and free Mg2+ ions. However, several kinetic constants such as Km, Vmax, Ka, and especially Ki were influenced to some extent. Whereas the affinity of the purine transport system to its substrate was not significantly changed by the growth conditions, an effect on Vnlax could be seen. Lower growth temperatures clearly led to higher maximal uptake velocities. The presence of paraquat during growth resulted in a considerable decrease of Vmax.

Repression of the Alkaline Phosphatase of Vibrio cholerae

Abstract: The synthesis of alkaline phosphatase by two strains of Vibrio cholerae belonging to the Inaba and Ogawa serotypes has been examined in relation to the phosphate concentration of the culture medium. The synthesis of the enzyme in both strains was repressed in cells grown in the presence of a high concentration of inorganic phosphate. Lowering the phosphate content of the growth medium led to a derepression of enzyme activity. The presence of glucose in low phosphate medium stimulated the degree of derepression. The synthesis of the enzyme by strain Inaba 569B was more sensitive to inorganic phosphate than that of strain Ogawa 154. The enzyme was presumably located in the periplasmic space since it was released when the organisms were converted to spheroplasts.

Improved growth medium for Campylobacter species.

Abstract: Campylobacter species were grown in a base containing proteose peptone no. 3, yeast extract, K2HPO4, (NH4)2SO4, NA2SO3, soluble starch, and agar. Concentrations and sources of organic nitrogen and growth factors were critical, and the optimal pH range was 7.0 to 7.5. Cultures tolerated 0.7% NaCl in addition to the salt present in the organic constituents and were sensitive to surface-active agents at concentrations recommended for enrichment of other gram-negative bacteria. Cultures were maintained on the proposed medium for 1 year with transfer every 2 weeks.

A serum protein inhibitor of acid lipase and its possible role in lipid accumulation in cultured fibroblasts.

Abstract: Histochemical examination of L929 fibroblasts indicates massive accumulation of intracellular lipids in cells grown in medium supplemented with 10% calf serum. The present study suggests that the accumulation of triacylglycerols in these cells may be due to the inhibition of acid lipase activity by a serum component present in the culture medium. This is based on the following observations. (a) Acid lipase appears to be the major intracellular enzyme responsible for triacylglycerol catabolism in L929 cells. (b) The acid lipase is strongly inhibited by either human of calf serum. Several lines of evidence show that the inhibitor is a serum protein: it is heat-labile, non-dialysable and is destroyed by trypsin. It is present mainly in Cohn's fraction IV and has mol.wt. approx. 50000. (c) Lipid accumulation in intact cells is reduced when cells are grown on a limited supply of serum (2%) and is elevated by the addition of Cohn's fraction IV, freed of lipoproteins, to the growth medium.

Fatty acid composition in herpetomonas samuelpessoai: influence of growth conditions

Abstract: 1. 1. The anteiso heptadecanoic, stearic, oleic, isononadecenoic (17-methyl-octadecenoic acid, an unusual branched unsaturated fatty acid) and eicosadienoic acids were major constituents of the fatty acids of Herpetomonas samuelpessoai grown under different conditions. 2. 2. Linoleic acid was the prominent fatty acid characterized in cells grown with different media, growth temperatures and incubation periods. 3. 3. Temperature and the culture age affected markedly the fatty acid composition in the total lipids of H. samuelpessoai; the degree of unsaturation decreased as the growth temperature was raised from 28 to 37°C on prolonging the incubation. 4. 4. The growth medium also influenced the fatty acid composition of cells; the levels of stearic (at 28 and 37°C) and isononadecenoic (at 28°C) acids decreased in cells cultivated in the complex as compared with the chemically defined medium at the same temperatures of incubation. 5. 5. This work makes a correlation between fatty acid composition and both cell differentiation and agglutination of H. samuelpessoai mediated by Concanavalin A.

Influence of chloramphenicol on growth and respiration of soybean (Glycine max L.) suspension cultures

Abstract: By addition of chloramphenicol (CAP) to the growth medium of green soybean (Glycine max L.) cells in batch culture, growth is inhibited and the activity of the cytochrome oxidase decreases to 60% of the value found in control cells. The presence of CAP induces an enhancement of the contribution of the alternative pathway to total respiration. This enlarged contribution results both from a higher capacity of the alternative pathway and from a greater part of this capacity being used. Also in mitochondria isolated from cells treated with CAP, a higher capacity of the alternative pathway has been found, while the part of this capacity which is really used is comparable with the values found in control cells.

Pyruvate-dependent diauxic growth of Rhodospirillum rubrum in light.

Abstract: When Rhodospirillum rubrum mutant C was first exposed to radiant energy after long-term anaerobic dark growth, the cells often exhibited a diauxic growth response. This happened with pyruvate in the medium and when cultures were exposed to a less-than-growth-saturating white light intensity of about 6,460 lx. Under the growth-saturating light condition, mutant C photometabolized and growth was not affected by Na hypophosphite, an inhibitor of pyruvate fermentation. In lower intensity light, in which diauxie occurred, initial (phase I) growth occurred by fermentation of Na pyruvate and was sensitive to Na hypophosphite inhibition. Once pyruvate was depleted, phase I growth stopped, the bacteriochlorophyll content of the cells began to increase from about 3 nmol/mg of protein, and growth finally resumed phototrophically (phase II). The lag period and phase II growth were influenced by radiant energy. By changing the white light intensity from 2,150 to 753 lx between experiments, the duration of both the lag period and the generation time of cells in phase II growth increased. Diauxic growth was pyruvate dependent. It occurred with pyruvate even if malate, a photometabolizable substrate, was added to the growth medium. Moreover, the biphasic growth response was reversible. It was observed not only with R. rubrum mutant C grown cells photosynthetically, but also when other strains of R. rubrum were placed in pyruvate medium under lowered light conditions. Only R. rubrum S1 did not exhibit the typical pyruvate-dependent diauxic growth response.

Effect of glucose concentration in the growth medium on the synthesis of fatty acids by the yeast Candida bogoriensis

Abstract: The yeast Candida bogoriensis produced large quantities of an extracellular glycolipid, the diacetyl sophoroside of 13-hydroxydocosanoic acid, when grown on a standard glucose rich medium (3% glucose, 0.15% yeast extract), but not when grown on a low glucose medium (0.5% glucose, 0.4% yeast extract) (A. J. Cutler and R. J. Light. 1979. J. Biol. Chem. 254: 1944–1950). Glucose levels also affected the quantity and distribution of the free fatty acid and triglyceride fractions synthesized by this organism. Cells grown on the low glucose medium contained palmitate and stearate as the major fatty acids in these two fractions, and a 3-h incubation with [1-14C]acetate led primarily to the labeling of these two acids. Cells grown on the standard enriched glucose medium contained relatively less stearate and more behenate than the low glucose grown cells, and the incorporation of [1-14C]acetate into stearate was decreased, while that into behenate was increased.Supplementation of low glucose grown cells with gluco...

Method for producing single and/or mixed strain concentrates of bacteria

Abstract: An improved method which differentiates or separates heterogeneous populations of fast and slow acid producing strains of bacteria by growth of the strains under closely controlled unique conditions so as to allow the selection of a colony of one or the other strains is described. Preferably a gelled, solid growth medium containing in admixture: (1) milk protein, a milk protein derivative, or a milk protein substitute; (2) an acid pH sensitive color change indicator; and, (3) a buffering agent is used. The colonies have a contrasting color within and around them because of the effect of the acid produced by the bacteria on the indicator. The growth of the bacteria is under anaerobic or near anaerobic conditions in order to achieve certainty in the colony selection for fast or slow acid production. The bacteria can also be mixed with phage which inhibit or kill the members of a heterogeneous or homogeneous population of bacteria on the medium and grown to produce phage resistant colonies. The relatively large colonies which exhibit enhanced acid production and proteolysis of the milk protein on the plating container are selected for commercial use in preparing fermented products, particularly fermented foods.

Isolation of a wheat cell line with altered membrane properties.

Abstract: A spontaneous dimethylsulfoxide (DMSO)-tolerant cell line was isolated from a cell culture of wheat (Triticum monococcum L.). The tolerant cells were able to grow in the presence of 4% DMSO. Cells formed from protoplasts of the tolerant line required DMSO for division in culture medium of high osmotic value.Fatty acid composition and the molar ratio of phospholipids/sterols suggest a more ordered membrane structure in the tolerant line. Accordingly, a lower K(+) influx rate was detected in the tolerant cells in comparison with the original line. These characteristics were maintained after 6 months' cultivation of the cells in DMSO-free growth medium. This suggested that genetic changes could be responsible for differences between the two cell lines.

DNA Binding Activity of Cells of Deoxyribonuclease-susceptible Floc Forming Pseudomonas sp.

Abstract: Cells of Pseudomonas strain C-120, cultivated under the conditions in which cells do not flocculate naturally, were flocculated with DNA prepared from Escherichia coli, indicating that DNA binding factor was constitutively present on the cell surface. On the other hand, release of DNA into the growth medium was observed accompanying flocculation of cells. The results suggest that release of DNA from cells is an important factor for flocculation. DNA binding activity of cells was abolished by treating cells with proteases, suggesting the DNA binding factor is a pro-teinaceous component. The effects of salts and 2, 4, 6-trinitrobenzene sulfonic acid on the cells suggested that amino groups were involved in the DNA binding reaction. The number of DNAs bound per cell was estimated to be about 10 molecules from reconstitution experiments using phage T4 DNA.

Improved bacterial growth medium and method of growing bacteria

Abstract: An improved powdered bacterial growth medium com- positon adapted to be admixed with water is described. The powdered growth medium includes an alkali metal cation in a compound A admixed with a compound B containing an anion which reacts with the alkali metal cation in compound A in an aqueous growth medium to form an essentially water insoluble salt or base, including the alkali metal cation and the anion, which is acid neutralizing. The water insoluble salt is thus formed in situ in the aqueous growth medium when compounds A and B are added to the aqueous solution. Also described is an improved method for growing acid producing bacteria in an aqueous growth medium by forming the insoluble salt or base. The resulting growth medium is particularly adapted for neutralizing acids generated during growth of lactic acid producing bacteria which are grown for use in various food fermentations.

Sterol content as a character for selecting yeast strains in enology

Abstract: ·Saccharomyces cerevisiae is regarded as a facultative anaerobe; oxygen may be required for the growth of the organism. This requirement is suppressed if the growth medium is supplemented with ergosterol and is absent if aerobically grown cells are used as the inoculum (DAVID and KIRSOP 1973). The study of sterol biosynthesis showed that molecular oxygen is required for the oxidative cyclization of squalene to lanosterol (POPJAK and CoRNFORTH 1960). The only known exception to this behaviour is Schizo­ saccharomyces japonicus (BULDER 1971). S. cerevisiae, grown anaerobically in the absence of unsaturated fatty acids and sterols, diminished its endogenous levels of these lipids by dilution as yeast numbers and mass increased. When the levels of unsaturated fatty acids and sterols reached approximately one quarter of those found in aerobically grown cells, the organisms stopped dividing and there was a decline in the protein synthesizing activity of the cells and the mitochondrial oxidative phosphor­ ylation became progressively uncoupled (AsTIN and HAsLAM 1977). In the mitochondria this was due to a loss of high molecular weight RNA. In the cytoplasm the effect was at the level of the ribosomes, but it was not caused by a loss of cell integrity. When oxygen was supplied, protein synthesis in mitochondria and cytoplasm was rapidly reactivated, even in the absence of cell growth. This reactivation was accompanied by a rapid