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Growth medium

About: Growth medium is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 59171 citations. The topic is also known as: culture medium & culture media.


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Journal ArticleDOI
TL;DR: It is concluded that the 3T6 fibroblast can synthesize and secrete an underhydroxylated form of collagen, and that the hydroxylation process is highly sensitive to specific environmental factors which have no comparable effect on the synthesis of its substrate.

58 citations

Journal ArticleDOI
TL;DR: Two extracellular invertases found in the growth medium of the suspension cultures were probably identical with those in the soluble fraction of callus and seedlings of sugar beets, because they showed similar behaviors during chromatography on DEAE-cellulose, and had similar activity profiles with changing pH and K(m) values for sucrose.
Abstract: Alkaline invertase was induced during the initiation of suspension cultures of single cells from leaf explants of sugar beets in Murashige-Skoog liquid medium which contained benzyladenine. This activity was barely detectable in the leaves themselves. In suspension cultures, the presence of both acid and alkaline invertases was detected; alkaline invertase was only present in the cytoplasm of the cultured cells, whereas acid invertase was present in the cytoplasm and cell walls, and was also detected in the culture medium. The cell wall contained at least three types of acid invertase; two of these activities were solubilized by saline (saline-released) and EDTA (EDTA-released), respectively, and the third remained tightly associated with the cell wall. Saline-released and EDTA-released invertases from the cell wall showed the significant differences in their properties: the saline-released enzyme had the highest affinity for sucrose among the invertases tested, and was easily bound to cell walls, to DNA, and to a cation exchanger, unlike the EDTA-released enzyme. Sucrose is the source of carbon for plant cells in suspension culture and is probably degraded in the cell wall by the saline-released invertase, which had the highest activity and the highest affinity for sucrose. Hexose products of this degradation would be transported to cytoplasm. Soluble invertase, EDTA-released invertase from the cell wall, and one of two extracellular invertases behaved similarly upon chromatography on DEAE-cellulose. They had similar activity profiles with changing pH, and similar Km values for sucrose. Thus it appears that they are identical. Two extracellular invertases found in the growth medium of the suspension cultures were probably identical with those in the soluble fraction of callus and seedlings of sugar beets, because they showed similar behaviors during chromatography on DEAE-cellulose, and had similar activity profiles with changing pH and Km values for sucrose.

58 citations

Journal ArticleDOI
TL;DR: A fair agreement with the theory of continuous culture for all metabolic curves could be established in growth of Saccharomyces cerevisiae LBG H 1022 on ethanol under steady‐state conditions.
Abstract: Growth of Saccharomyces cerevisiae LBG H 1022 on ethanol under steady-state conditions was studied. As a cultivation device, an aerated Chemap fermentor combined with continuously working gas analyzers for oxygen and carbon dioxide was used. Dry matter, substrate concentration, yield, specific oxygen uptake, specific carbon dioxide release, and respiration quotient, as well as nitrogen, carbon, phosphorus, hydrogen, and protein content of the cells were measured in dependence on the dilution rate. Cell size distribution, as a function of the specific growth rate, was determined with the aid of a Celloscope 202. A fair agreement with the theory of continuous culture for all metabolic curves could be established. An increased turnover rate resulted from the addition of glutamic acid to the synthetic growth medium. The primary effect of this supplement could be a rise in the flow rate of the tricarboxylic acid cycle.

58 citations

Journal ArticleDOI
TL;DR: There are two signals, proline induction and quality of nitrogen source, impinging on Put3p that act synergistically for maximum expression of the proline utilization pathway, and this report demonstrates by phosphatase treatment of immunoprecipitates of extracts metabolically labeled with32P or 35S that Put3P is a phosphoprotein.
Abstract: Saccharomyces cerevisiae cells can sense the quality of the nitrogen source in their environment, enabling them to utilize preferred nitrogen-containing compounds over nonpreferred ones or to express pathways for the utilization of alternative nitrogen sources when the preferred ones have been consumed. Although very little is known about the sensing mechanism itself, work over the last decade has led to the discovery of a set of regulatory proteins, the GATA factors, whose role is to regulate, in both positive and negative directions, the expression of pathways of nitrogen assimilation in yeast. These proteins, Gln3p (26), Nil1p/Gat1p (10, 44), Dal80p/Uga43p (12, 13), and Nil2p/Gzf3p/Deh1p (11, 34, 42), are involved in a complex set of regulatory loops, competition for GATA binding sites, and possibly even some autoregulation. Recently, the coactivator Ada1p, isolated as Gan1p, was identified as a link between the GATA binding proteins and the basal transcriptional machinery (41). Global nitrogen repressor Ure2p is believed to interact with Gln3p to obtain appropriate expression of a variety of nitrogen assimilatory pathways (3; reviewed by Magasanik [23]). In their natural habitat, S. cerevisiae cells are found on grapes and in grape must, a nitrogen-poor environment where the most abundant nitrogen source is proline (2). Although proline is the least-preferred nitrogen source for many laboratory yeast strains and although its utilization results in the slowest growth rates, yeast cells have evolved a regulatory circuit that enables them to use the proline in the environment when preferred nitrogen sources are no longer available. The flux of proline into yeast cells is controlled by the activities of the general amino acid permease Gap1p and the proline-specific permease, Put4p (21). These permeases are regulated by nitrogen repression and do not respond to proline induction (17, 21, 43). The enzymes of the proline utilization pathway are induced by the presence of proline (6), and their levels reflect internal proline levels. The PUT1 and PUT2 genes encoding the enzymes of the pathway are regulated by Put3p, a member of the Zn(II)2Cys6 binuclear cluster protein family (4, 6, 7, 15, 24, 25, 40, 45, 49) and a close relative of Gal4p, the activator of the galactose utilization pathway. In vivo, Put3p binds the promoters of PUT1 and PUT2 in the presence or absence of proline and without regard to the quality of the nitrogen sources present in the growth medium (1) but activates transcription to a maximum level when proline is the sole source of nitrogen. PUT1 and PUT2 are repressed by Ure2p and in some, but not all, strain backgrounds are regulated by some of the GATA factors (9, 14, 50). This report presents the results of studies on wild-type and regulation-defective mutant Put3 proteins in cells grown in media containing different nitrogen sources. We show that Put3p is differentially phosphorylated as a function of the quality of the nitrogen source and that the slowest-migrating species of Put3p are correlated with elevated transcriptional activity. Analysis of the Put3p phosphoforms of activator-defective and activator-constitutive mutants leads to the suggestion that altered phosphorylation status may be one of two signals (proline induction being the other) that is required for maximum transcriptional activity by Put3p.

58 citations

Journal Article
TL;DR: It is shown that the cytotoxic anticancer agent Adriamycin can stimulate the proliferation of some cells and is not limited in its action solely to cytotoxicity.
Abstract: Adriamycin causes a variety of biological actions and is an effective cytotoxic agent against proliferating cells. In this paper we show that the drug is not limited in its action solely to cytotoxicity, but can also stimulate cell growth under the appropriate conditions. Using the survival assay of cloning in soft agar, we present data showing that the conditions for Adriamycin-induced growth stimulation are that the drug be in a subtoxic concentration range of 10(-10)-10(-9) M (greater than 10(-8) M causes cytotoxicity) and that the growth medium be suboptimal. This latter condition is satisfied by either growing cells for an extended period in order to exhaust the growth supporting capacity of the medium, or by growing the cells at low (less than 10%) serum concentrations. Several active anthracycline congeners also have the ability to stimulate growth. The results indicate that the cytotoxic anticancer agent Adriamycin can stimulate the proliferation of some cells.

58 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20233
20226
202126
202032
201926
201829