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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
01 Jan 1993-Yeast
TL;DR: Analysis of the effects of different environmental parameters on excretion of Escherichia coli β‐galactosidase obtained by exploiting the glucoamylase II signal sequence indicates that optimization of environmental parameters may help the excreted of heterologous proteins, offering advantages for protein purification.
Abstract: In the budding yeast Saccharomyces cerevisiae the cell wall, mainly composed of mannoproteins and glucans, constitutes a barrier to protein excretion in the growth medium. In this paper we have studied the effects of different environmental parameters on excretion of Escherichia coli beta-galactosidase obtained by exploiting the glucoamylase II signal sequence. Excretion of the unglycosylated beta-galactosidase was detectable only in cells grown in rich medium, was affected by temperature (36 degrees C > 30 degrees C >> 24 degrees C) and slightly stimulated by reducing agents. On the contrary, glycosylated proteins, such as alpha-galactosidase and glucoamylase II, were excreted to a good extent under all tested conditions of medium composition, growth temperature and pH. These data indicate that optimization of environmental parameters may help the excretion of heterologous proteins, offering advantages for protein purification.

36 citations

Journal ArticleDOI
TL;DR: The data presented indicate that glucose metabolism in Euglena is similar to that found in a wide variety of other cells, and it is concluded that citrate was acting as a chelator.
Abstract: SYNOPSIS. A number of small molecules including CO2, certain Krebs cycle acids and certain amino acids stimulated growth and glucose utilization of a colorless strain of Euglena gracilis in a phthalate-buffered mineral salts medium. Their major effect was to shorten markedly the lag period; some compounds also gave small increases in maximum growth rate and total cell yield. The stimulatory substances were effective in small (sparking) amounts. It is suggested that all the stimulatory substances acted similarly, by keeping the internal concentration of oxaloacetate at a sufficiently high level to allow effective operation of the terminal respiratory cycle. Glucose utilization was initiated within a pH range of 3.0 to 5.0. This range could be extended by the addition of glycine to the growth medium. Cells cultured at pH 4.5 could be adapted to growth at pH 7.0 in a phosphate-buffered mineral salts medium containing a small amount of citrate. Neither adaptation nor growth occurred at pH 7.0 in the absence of citrate. Since no evidence of citrate utilization was obtained and since EDTA replaced citrate, it is concluded that citrate was acting as a chelator. The major enzymes of the Embden-Meyerhof-Parnas and pentose phosphate pathways were demonstrated in cell-free extracts. The data presented indicate that glucose metabolism in Euglena is similar to that found in a wide variety of other cells. Indirect evidence was also obtained for the operation of a uridine linked pathway in hexose metabolism. With the exception of hexokinase, for which results were inconsistent, all the enzymes demonstrated were routinely found in the supernatant fraction of the cell-free extracts. The pH optima of a number of the enzymes were found to be between pH 7.5 and 8.6, although the cells from which the enzymes were obtained were grown in acid medium.

36 citations

Journal ArticleDOI
TL;DR: The effect of eight different macronutrient formulations on the in vitro culture of Gatharanthus roseus nodes was investigated: the caulogenesis rate decreased with the overall ion concentration and the ammonium content of the growth medium.
Abstract: Plant tissue culture requires the optimization of growth media. The effect of eight different macronutrient formulations on the in vitro culture of Gatharanthus roseus nodes was investigated: the caulogenesis rate decreased with the overall ion concentration and the ammonium content of the growth medium. The methodology proposed for the optimization of the mineral composition of the growth medium is based upon the adjustment of the macronutrients contents to the plant requirements. Such an approach was used for the comparison between the effects of the optimized growth medium and those of the usual Murashige and Skoog solution in the growth of the multiple shoots issued from Solatium paludosum root calluses. The new formulation MH1 [with a diminution of the ionic concentration, nitrogen (N) supplied in the form of nitrate and calcium (Ca) in larger amounts than potassium (K)] doubled the biomass production and tripled the yield of solamargine, a secondary metabolite.

36 citations

Journal ArticleDOI
TL;DR: An attempt is made to investigate the influence of the source of tryptone in the growth medium on the resistance of Escherichia coli to various types of oxidative stress.
Abstract: Aims: To investigate the influence of the source of tryptone in the growth medium on the resistance of Escherichia coli to various types of oxidative stress. Methods and Results: Cultures of Escherichia coli MG1655 were grown in Luria–Bertani (LB) medium at 37°C to stationary phase, harvested, and subsequently subjected to various types of oxidative stress. A marked difference in oxidative stress sensitivity was observed depending on the origin of the tryptone in the LB medium used to grow the cultures. Cells harvested from LB containing tryptone from source x (LBx) were more sensitive to inactivation by the superoxide generating compound plumbagin and by t-butyl peroxide, and to growth inhibition by the lactoperoxidase enzyme system, than cells harvested from LB containing tryptone from source y (LBy). By monitoring expression of a panel of stress gene promotors linked to the gfp (green fluorescent protein) gene, and using Δ2–22 alkaline phosphatase as a probe for disulphide bridge formation from protein sulphydryl groups, it was demonstrated that a greater cytoplasmic oxidative stress existed in cells during growth in LBy than in LBx. Conclusions: Depending on the source of tryptone, bacteria may experience different levels of oxidative stress in tryptone-containing nonselective growth media. Although these levels of oxidative stress are subinhibitory, they may trigger a stress response that makes the bacteria more resistant to a subsequent exposure to a lethal or inhibitory level of oxidative stress. Significance and Impact of the Study: This work highlights the importance of controlling very subtle differences in composition of nonselective growth media in studies on bacterial physiology.

36 citations

Journal ArticleDOI
TL;DR: Clostridium magnum, originally described as a non-autotrophic homoacetogenic bacterium, was found to be able to grow with H2/CO2, formate, or methanol with stoichiometric acetate formation, provided that the growth medium contained at least 0.025% yeast extract.
Abstract: Clostridium magnum, originally described as a non-autotrophic homoacetogenic bacterium, was found to be able to grow with H2/CO2, formate, or methanol with stoichiometric acetate formation, provided that the growth medium contained at least 0.025% (w/v) yeast extract. Hydrogen was also formed as a byproduct of glucose fermentation, and was consumed again after glucose consumption. Hydrogen formation from glucose was independent of growth conditions and reached similar maximal concentrations in mineral media with or without ammonia added as well as in non-growing cultures or in the presence of carbon monoxide.

36 citations


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