Showing papers on "Growth medium published in 1979"

Astaxanthin Formation by the Yeast Phaffia rhodozyma

Abstract: Summary: The production of carotenoid pigments by the yeast Phaffia rhodozyma depended on the culture conditions. Astaxanthin, the primary carotenoid in this yeast, was produced mainly during the exponential phase of growth. The concentration of carotenes in P. rhodozyma remained relatively constant [about 5 μg (g yeast)−1] throughout growth in a 1.5% (w/v) glucose medium, but the xanthophyll concentration increased from 90 to 406 μg (g yeast)−1 during fermentation. Active xanthophyll synthesis occurred during the period of accelerating growth and after exhaustion of glucose from the growth medium. In media containing more than 1.5% (w/v) glucose, however, yeast and carotenoid yields were considerably reduced. The pH of the medium affected yeast yields and carotenoid production; the optimum pH was 5.0. At pH 3.5, β-zeacarotene accumulated in P. rhodozyma. β-Carotene was the primary carotene in the yeast under all other conditions tested. The optimum temperature for yeast growth and pigment formation was 20 to 22.C and the best carbon source was d-cellobiose. Oxygen was an important substrate for optimum yields of yeast and astaxanthin; under microaerophilic growth conditions, astaxanthin production was drastically decreased and P. rhodozyma accumulated β-carotene and the monoketone echinenone.

Influence of Iron on Yields of Extracellular Products in Pseudomonas aeruginosa Cultures

Abstract: The effect of the iron content of the medium on the yields of extracellular products by seven distinct strains of Pseudomonas aeruginosa was examined. All strains showed at least an 85% decrease in toxin A yields when grown in medium containing 5.0 μg of iron per ml (high iron) as compared to 0.05 μg/ml (low iron), whereas bacterial growth increased approximately twofold. During the course of examining extracellular products produced by P. aeruginosa, we found many strains that produced an extracellular factor which agglutinated erythrocytes. This hemagglutinin was nondialyzable, heat stable, and resistant to Pronase and trypsin. The effect of iron on extracellular yields of hemagglutinin was strain dependent; four of seven strains showed decreases in hemagglutinin yields in high-iron medium. Similarly, the effect of increasing the iron concentration of the growth medium on yields of total extracellular proteases or on elastase was strain dependent. The amount of total extracellular protein was decreased by at least 31% in the high-iron medium for all strains of P. aeruginosa examined. Detailed studies on one strain (WR-9) showed that, in the presence of increasing amounts of iron in the medium, the extracellular yields of toxin A, protease, and hemagglutinin were decreased in a similar manner. In addition, the kinetics of release of these extracellular products were similar at a given iron concentration. Thus it appears that the yields of other extracellular products of P. aeruginosa besides toxin A are influenced by the concentration of iron in the growth medium.

Effects of low concentrations of zinc on the growth and dimorphism of Candida albicans: evidence for zinc-resistant and -sensitive pathways for mycelium formation.

Abstract: In this analysis we have examined in detail the effects of low concentrations of zinc on the growth and dimorphism of Candida albicans. Evidence is presented that micromolar concentrations of zinc added to growth cultures grown at 25 degrees C (i) cause a twofold increase in the final concentration of spheres at sationary phase, (ii) result in an asynchronous block in the budding cycle at stationary phase, (iii) completely suppress mycelium formation in two independently isolated human strains which produce low but significant levels of mycelia at stationary phase, and (iv) completely suppress mycelium formation in cultures of mutant M10, in which over 60% of the cells form mycelia at stationary phase. In contrast, micromolar concentrations of zinc do not inhibit mycelium formation induced by releasing cells from stationary-phase cultures into fresh medium at 37 degrees C. In addition, if zinc is present in the growth medium of the initial culture at 25 degrees C, the average time of subsequent mycelium formation after release into fresh medium at 37 degrees C is halved. It is demonstrated that the above effects are specific to zinc. The possibility of alterante pathways for mycelium formation is suggested, and the medical implications of this possibility are discussed. Images

Effect of inorganic sulfide on the growth and metabolism of Methanosarcina barkeri strain DM.

Abstract: Minimal growth of Methanosarcina barkeri strain DM occurred when sulfide was omitted fromthe growth medium, and addition of either sodium sulfate or coenzyme M to sulfide-depleted media failed to restore growth. Optimal growth occurred in the presence of 1.25 mM added sulfide, giving a molar growth yield (YCH4) of 4.4 mg (dry weight) of cells per mmol of CH4 produced. Increasing sulfide to 12.5 mM led to decrease in YCH4 (1.9 mg [dry weight]/mmol of CH4), in the specific growth rate and in be intracellular levels of adenosine triphosphate. However, the specific rate of methane production increased. The data suggested that at elevated sulfide levels (12.5 mM) the decrease in YCH4 might be a result of an increase in the relative energy needed for maintnenace and of uncoupling of growth from energy production.

Uptake of trehalose by Saccharomyces cerevisiae.

Abstract: SUMMARY: Trehalose, a storage sugar of baker's yeast, is known not to be metabolized when added to a cell suspension in water or a growth medium and to support growth only after a lag of about 10 h. However, it was transported into cells by at least two transport systems, the uptake being active, with a pH optimum at 5·5. There was no stoicheiometry with the shift of protons into cells observed at high trehalose concentrations. Trehalose remained intact in cells and was not appreciably lost to a trehalose-free medium. The uptake systems were present directly after growth on glucose, then decayed with a half-life of about 25 min but could be reactivated by aerobic incubation with trehalose, maltose, α-methyl-D-glucoside, glucose or ethanol. The uptake systems thus induced were different as revealed by competition experiments. At least one of the systems for trehalose uptake showed cooperative kinetics. Comparative analysis with other disaccharides indicated the existence in Saccharomyces cerevisiae, after induction with trehalose, of at least four systems for the uptake of α-methyl-D-glucoside, four systems for maltose, together with the two for trehalose, variously shared by the sugars, the total of α-glucoside-transporting systems being five.

Growth of Normal and Malignant Human Mammary Epithelial Cells in Culture

Abstract: Normal and malignant human mammary epithelial cells were placed in culture. Normal cells were recovered from late-lactation milk and breast fluids, and malignant cells were isolated from primary breast tumors by collagenase digestion. The concentration of cells obtained from breast fluid samples was inversely proportional to the volume of fluid secreted. Most of these cells adhered rapidly to the substrate, did not replicate, displayed Fc receptor-dependent phagocytic activity, and were thus identified as macrophages. The remaining cells grew out into large islands comprised of one or two distinct morphologic types of mammary epithelial cells. Optimum growth of these cells was obtained in medium buffered to pH 6.8, and the epidermal growth factor markedly prolonged the exponential growth phase of the cells. Two morphologically distinct populations of epithelial cells were also observed in cultures established from individual breast tumors. Growth of the malignant cells was relatively unaffected by the pH of the culture medium, and the cells were unresponsive to exogenously added hormones. Overgrowth of malignant epithelial cells in primary cultures by stromal fibroblasts was retarded by replacement of standard growth medium with fresh medium containing a serum substitute; growth of the malignant epithelial cells was unaffected. A feeder layer of mitomycin C-treated human fibroblasts increased the plating efficiency of both normal and malignant cells in primary culture and also facilitated passage of these cells to secondary and tertiary cultures.

Comparison of m-Endo LES, MacConkey, and Teepol media for membrane filtration counting of total coliform bacteria in water.

Abstract: Total coliform counts obtained by means of standard membrane filtration techniques, using MacConkey agar, m-Endo LES agar, Teepol agar, and pads saturated with Teepol broth as growth media, were compared. Various combinations of these media were used in tests on 490 samples of river water and city wastewater after different stages of conventional purification and reclamation processes including lime treatment, and filtration, active carbon treatment, ozonation, and chlorination. Endo agar yielded the highest average counts for all these samples. Teepol agar generally had higher counts then Teepol broth, whereas MacConkey agar had the lowest average counts. Identification of 871 positive isolates showed that Aeromonas hydrophila was the species most commonly detected. Species of Escherichia, Citrobacter, Klebsiella, and Enterobacter represented 55% of isolates which conformed to the definition of total coliforms on Endo agar, 54% on Teepol agar, and 45% on MacConkey agar. Selection for species on the media differed considerably. Evaluation of these data and literature on alternative tests, including most probable number methods, indicated that the technique of choice for routine analysis of total coliform bacteria in drinking water is membrane filtration using m-Endo LES agar as growth medium without enrichment procedures or a cytochrome oxidase restriction.

Effects of Azotobacter chroococcum on Barley Seed Germination and Seedling Development

Abstract: When cells or the culture filtrate of Azotobacter chroococcumgrown on a medium without a source of fixed nitrogen were added to barley seeds, they sometimes stimulated the extension of seedling roots. The stimulation appeared to be due to a bacterial metabolite as the cells used were non-viable (due to a decrease in pH of the growth medium). There was no evidence that 3-indoleacetic acid or gibberellic acid, which were produced by the bacterium, were involved in the stimulation. When the bacterium was grown on a medium containing nitrate, the cells, but not the culture filtrate, always inhibited germination and the extension of seedling roots. This inhibition of germination appears to be due to competition between viable bacteria and seed for available oxygen.

Synthesis of L-asparaginase by Serratia marcescens (Nima)

Abstract: The production of L-asparaginase by two mutants of Serratia marce- scens grown on 14 different media was studied. The enzyme content increased from trace levels to 2·4 international units per ml when the organisms were grown in glycerol-peptone yeast extract medium. Glucose was the best carbon source under aerobic conditions. The enzyme content increased when L-asparagine was present in the growth medium.

Glycoprotein synthesized by cultured cells: effects of serum concentrations and buffers on sugar content.

Abstract: SummaryA cell line derived from a murine teratocarcinoma was cultured in growth medium supplemented with either 10% or 1% fetal bovine serum or was grown in chemically-defined medium buffered with either a combination of HEPES and sodium bicarbonate or with bicarbonate alone. The sugar content of a particular glycoprotein secreted by these cells was markedly different in each case. No differences were noted in antigenicity or amino acid composition, including amino and carboxyl terminal amino acids. Differences in molecular weight were attributable to the difference in carbohydrate content. These data indicate that the level of glycosylation of proteins in vitro is dependent on the medium composition, including apparently unsuspected components such as buffers.

Mechanisms of protein degradation in growing and non-growing L-cell cultures.

Abstract: L-cells prelabelled with [14C]leucine and [3H]thymidine were placed in either fresh growth medium (minimal essential medium with 10% serum) or stepdown medium (minimal essential medium) for 3 days. The 14C/3H ratio remained constant in the growing cultures and decreased in the stationary-phase cultures, indicating no protein turnover in growing cultures and a degradative rate of 0.6%/h in the stationary-phase cultures. Media analysis, however, indicated that 14C-labelled proteins were being degraded at approx. 1.2%/h in growing cultures and 1.7%/h in stationary-phase cultures. Additional studies indicated that a subpopulation of L-cells in the monolayer, comprising approx. 20--30% of the total, were lost in the original processing procedure. Experiments in which recoveries approached 100% by fixation of the monolayer in situ indicated that a protein-degrading subpopulation accounted for all the observed proteolysis in the growing cultures. Proteolysis in these cultures was only partially inhibited with NH4Cl, indicating that only a small part of the protein degradation was occurring in an activated lysosomal-autophagic system. NaF produced a more effective inhibition of proteolysis, but we were not able to distinguish whether this effect was on an ATP-requiring basal-turnover mechanism or a direct effect on unregulated activity of proteinases in the cell hyaloplasm. However, NH4Cl inhibited the proteolysis induced when cells were placed in stepdown medium, suggesting that the induced proteolysis was occurring via the autophagic system. We conclude that L-cells exist in at least two states with respect to protein degradation: (a) a subpopulation that is actively replicating and does not degrade cellular proteins, and (b) a second subpopulation of cells, derived from the preceding one, which degraded most of their labelled proteins, are not capable of further replication, and are not sedimented in an iso-osmotic EDTA buffer solution. In addition, proliferating L-cells, when placed in stepdown medium, begin to degrade cell protein through a mechanism involving autophagolysosomes.

Expression of aspartokinase, dihydrodipicolinic acid synthase and homoserine dehydrogenase during growth of carrot cell suspension cultures on lysine- and threonine-supplemented media.

Abstract: Reduction in the amounts of activity of the first enzyme, aspartokinase (EC 2724) and two branch-point enzymes, dihydrodipicolinic acid synthase (EC 42152) and homoserine dehydrogenase (EC 1113), located in the pathway for the synthesis of aspartate-family amino acids, occurred when cell suspension cultures of Daucus carota L var Danvers were grown in media containing 2 mM threonine or 2 mM lysine, endproducts of the pathway Activity of the lysine-sensitive form of aspartokinase was decreased when cells were grown in medium containing lysine and the activity of the threonine-sensitive form was decreased when cells were grown in medium containing threonine Activity of the branch-point enzyme leading to threonine synthesis, homoserine dehydrogenase, was decreased up to 70% in specific activity (units/mg protein) and relative activity (units/g fresh weight) when cells were grown in media containing lysine or threonine Threonine had no effect on the relative activity of dihydrodipicolinic acid synthase, but decreased its specific activity Lysine decreased the relative activity of the synthase by up to 40%, but had little effect on its specific activity The decreased activities of the enzymes were apparently not due to binding of the inhibitory amino acids to the enzymes since homogenization of cells in buffer with 2 mM lysine and threonine did not decrease the measurable enzyme activities These and other results presented suggest that both forms of the aspartokinase activity and homoserine dehydrogenase activity can be altered by supplementing the growth medium with lysine or threonine

Effect of growth medium on the relative polypeptide composition of cellular outer membrane and released outer membrane material in Escherichia coli.

Abstract: When ratios of the major polypeptides of the outer membrane isolated from cells of Escherichia coli B grown in minimal medium containing either a single amino acid or several amino acids were compared, no difference was observed. However, the ratio of these polypeptides in outer membrane material released into the medium during logarithmic phase growth on these two media was markedly different.

Acid hydrolases and their release in food vacuole-less mutants of Tetrahymena thermophila.

Abstract: Mutants (NP1 and PSJ5) of Tetrahymena thermophila strains B and D 1968 exist that are unable to construct a functional oral apparatus and form food vacuoles at 37 C but which do so normally at 30 C. Food vacuole-less cells starved in dilute salt solution released similar amounts of acid phosphatase, beta-N-acetyl-glucosaminidase and alpha-glucosidase activity into the medium as wildtype cells during an 8-h period. Actively growing, food vacuole-less cells had approximately 50% less total protein, acid phosphatase, beta-N-acetyl-glucosaminidase, and alpha-glucosidase per cell than wildtype cells after 72-h growth. During this time food vacuole-less cells released significant amounts of the 3 acid hydrolases into the growth medium. For each hydrolase, the total activity released from growing, food vacuole-less cells was less, on a per cell basis, tahn the amount released from food vacuole formers. The proportion of the total activity secreted by the mutant and the wildtype cells was the same for acid phosphatase and beta-N-acetyl-glucosaminidase and somewhat lower for alpha-glucosidase. It is concluded that the release of a significant amount of acid hydrolase activity from Tetrahymena is independent of food vacuole formation and may be analogous to the secretory activity of other nonphagocytic eukaryotic cells.

Cell surface‐associated ribonuclease activities

Abstract: The ribonuclease (RNase) activity associated with the surface of cells (primarily the Vero line of Green monkey kidney) was assayed under conditions where all cells remained viable as members of colonies or monolayers. RNase activity associated with individual clones was revealed as clear zones of hydrolyzed (acid-soluble) RNA against an opaque background of acidprecipitated RNA in an isotonic agarose-yeast RNA overlay. High resolution assays for single- and double-stranded RNase were achieved by measuring the loss in activity of infectious Sindbis virus RNA, and of the antiviral state induced by poly(rI). poly(rC), respectively. Experiments using these assay procedures revealed that virtually all of the RNase activity associated with viable (intact) vertebrate cells in culture was contributed by the serum in the growth medium, and was superficially adsorbed to the cell surface, rendering it relatively easy to remove by extensive washing. A confluent monolayer of 2 × 106 unwashed Vero cells contained the equivalent of 500 ng of pancreatic RNase, representing about 5% of the total activity initially present in the serum of the growth medium. In terms of serum nuclease activity, only 0.45 ng equivalents of pancreatic RNase in 500 μl were required to destroy 50% of the activity of an infectious Sindbis virus RNA preparation in 15 minutes at 37°C. Cells grown in the absence of serum and cells washed about ten times had comparably low levels of RNase activity–about 100-fold less than unwashed cells grown in the presence of 6% calf serum. The isotonic yeast RNA:agarose overlay procedure may be useful to identify and isolate cell mutants with different endogenous levels, or binding capacities, of surface RNase activity. Operationally, these studies describe the assay of cell surface-associated RNase activity under conditions where all cells remain viable as members of individual colonies or monolayer populations. Specifically, the assay measures the solubilization of yeast RNA in an isotonic agarose mixture overlaying the cells. We describe its use to determine how much of the total RNase activity in viable cell monolayers or colonies is contributed by serum in the growth medium. In addition, we describe the results of two biological assays used as higher resolution probes for cell surface ribonuclease activity: (i) single-strand (ss) RNA, in the form of infectious RNA from Sindbis virus, and (ii) double-stranded(ds)-RNA, in the form of poly(rI). poly(rC) as an inducer of an interferon-mediated antiviral state.

Low protein degradation product basal medium for identification of non-fermentative gram-negative bacilli and other microorganisms

Abstract: A single basal growth medium for receiving various substrates for the purpose of rapid identification of any species of non-fermentative Gram-negative bacilli (NFB), wherein the medium is low in organic nitrogen but is supplemented with inorganic nitrogen from an ammonium ion source to enhance NFB growth. The medium also serves to identify members of the family Enterobacteriaceae, cytochrome oxidase positive fermenters, Gram-positive bacilli, Gram-positive cocci, and anaerobes.

Studies on the control of development. Highly phosphorylated nucleotides (HPN) are correlated with ascospore formation in Saccharomyces cerevisiae.

Abstract: Saccharomyces cerevisiae strain 1–2d can be induced to sporulate upon shift from rich growth medium to poor (potassium acetate) sporulation medium. Asci are observed after 24–30 h. Ascus formation is suppressed by the addition of nitrogen sources (yeast nitrogen base). When 32P-labelled phosphate is added to the sporulation medium and formic acid extracts of cells are chromatographed it is found that three highly phosphorylated nucleotides are produced almost immediately after shift down. These substances have been clearly identified as adenosine-5′,3′(2′)-bis-diphosphate (p2Ap2), adenosine-5′-triphosphate-3′(2′)-diphosphate (p3Ap2), and adenosine-5′,3′(2′)-bis-triphosphate (p3Ap3) by comparison with authentic samples obtained from sporulating B. subtilis cells.

Purification and partial characterization of an antibiotic produced by myxococcus coralloides

Abstract: A strain of Myxococcus coralloides producing an antibiotic capable of inhibiting growth of Gram-positive bacteria was isolated. Antibiotic production occurred during vegetative growth but not during myxospore formation. The antibiotic was extracted from the growth medium with chloroform and purified by adsorption on silicic acid and by preparative silica gel thin-layer chromatography. The purified antibiotic showed a resistance to heat, acid, alkali and proteolytic enzymes. Chromatographic and electrophoretic behavior as well as infrared, ultraviolet and mass spectra are presented.

Chemical changes in the growth medium of microcystis, batch cultures grown at stress and non-stress light intensities

Abstract: SUMMARY The modified BG 11 growth medium used in this study has a poor buffer ability and large pH changes occurred during growth of Microcystis. Inhibition of growth in cultures grown at stress light intensity (26 μEinst m−2 sec−1) could be ascribed to depletion of the total inorganic carbon content of the medium rather than to light intensity per se, pH or high O2 concentration. In cell suspensions grown under stress light intensity an unfavourably low CO2: O2 concentration ratio developed due to rapid photosynthesis and insufficient replenishment of CO2 by diffusion from air which may have induced oxygenation instead of carboxylation by ribulose diphosphate carboxylase.

Transformation of feline embryo cells in culture by a chemical carcinogen.

Abstract: A feline embryo cell line was treated in vitro with various levels of 7,12-dimethylbenz[a]anthracene (DMBA) or dimethyl sulfoxide (control) Repeat treatment of DMBA only induced in vitro transformation of feline embryo cells following clonal growth and selection The morphologically altered cells formed large cell aggregates and grew in this aggregate form when suspended in liquid growth medium above an agar base, formed colonies in soft agar, and grew to high saturation densities However, no progressively growing tumors were produced when cells were inoculated into nude athymic mice The transformed lines were negative for feline oncornavirus-associated cell membrane antigen (FOCMA)

Changes in sporulation potential during the growth cycle of Bacillus subtilis.

Abstract: The sporulation potential of Bacillus subtilis as a function of position in the cell cycle was determined by transferring cells from growth medium to sporulation medium at various times during growth Growth was induced by incubating heat-activated spores in rich medium or by diluting stationary phase vegetative cultures with fresh growth medium The results supported earlier observations that sporulation potential is cell cycle dependent The rise in sporulation potential was studied by exposing cultures to the inhibitors of cell wall and protein synthesis, vancomycin and chloramphenicol The delay in the appearance of the peak of sporulation potential caused by these inhibitors compared with the reported lack of effect of nalidixic acid, indicates that the appearance of sporulation potential requires synthesis of a macromolecular component other than deoxyribonucleic acid The effect of nalidixic acid in preventing the decline of the sporulation potential was compared with the effect of high temperature on a mutant temperature sensitive for the initiation of DNA replication It was found that prevention of chromosome completion with nalidixic acid maintained a high sporulation potential, whereas prevention of chromosome re-initiation in the temperature sensitive mutant did not affect the decline in sporulation potential as the cells enter stationary phase

Process for the growth of baker's yeast on acid whey

Abstract: Acid whey, the by-product from the manufacture of fresh cheeses such as cottage cheese, is clarified, filtered and subjected to lactose hydrolysis, splitting the lactose disaccharide into the monosaccharides glucose and galactose. The liquid is sterilized and cultured with Saccharomyces yeast e.g. Baker's yeast and used as a growth medium for that yeast. After yeast growth is substantially completed the yeast solids are separated and the liquid remaining is discharged into waste-water receiving systems, the liquid significantly reduced in organic waste loading as compared to untreated acid wheys.

Storage Death at Low Temperature (- 18 "C) of Strains of Escherichia coli with Different Repair Capacities

Abstract: The bacterial strains are listed in Table 1. The growth medium was LB medium [l % (w/v) Bacto tryptone, 0.5 % (w/v) Bacto yeast extract, 1 % (w/v) NaCI] and was solidified, where necessary, with 1-6 % (w/v) agar (Difco). Liquid cultures were grown to stationary phase at 30 or 37 "C. Each culture was then divided into two. One half was centrifuged and washed twice with buffered saline [0.7 % (w/v) Na,HPO4.7H,O, 0.3 % (w/v) KH2P04, 0.4 % (w/v) NaCl; pH 7-01, and finally resuspended in the original volume of buffered saline. To both this suspension and the other half of the culture, glycerol was added to give 50 % (v/v), to prevent freezing. From these suspensions, 0-3 ml portions were transferred to unsealed 2 ml ampoules and placed at the bottom of a freezer chest at - 18 "C. Survival was measured by placing ampoules in a 20 "C water bath, and then plating appropriate dilutions by the agar layer method (bottom layer, 25 ml solidified LB medium; top layer, 2.5 ml containing 0.9 % NaCl and 0.7 % agar; a third layer of this soft agar was added to ensure that all colonies would be within the agar). Colonies were counted after 2 d at 37 "C.

Agar slush as a method to insure homogeneity of monocentric fungi in continuous culture.

Abstract: Agar granules suspended in the growth medium reduce clumping, which permits the continuous culture of monocentric chytridiomycete fungi.

Differential synthesis of an alkaline endonuclease in Physarum polycephalum

Abstract: During the sclerotization of microplasmodia of Physarum polycephalum in non-nutrient salt medium or in salt medium supplemented by glucose, RNA or nucleotides a 6-fold increase in the specific activity of an alkaline endonuclease was found within 6 h after the induction. The increase was based on de novo synthesis of the enzyme and it was strongly correlated to the sharp drop in the level of cellular RNA in the first hours of the process of scerotization. The induction in exhausted growth medium or in salt medium supplemented by protein or mannitol showed a gradual 2-3-fold increase of the endonuclease in 30 h, parallel to the gradual decrease of the RNA. No changes in the specific activity of the endonuclease were found during logarithmic growth or under conditions of starvation without the induction to sclerotization.