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.

Application of a MTT assay for screening nutritional factors in growth media of primary sponge cell culture

Abstract: Marine sponges (porifera) are producers of the largest variety of bioactive compounds among benthic marine organisms. in vitro culture of marine sponge cells has been proposed for the sustainable production of these pharmacologically interesting compounds from marine sponges but with limited success. the development of a suitable growth medium is an essential prerequisite for sponge cells grown in vitro. the mtt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was adapted to screen for potential nutritional factors in formulating a growth medium for primary cell culture of suberites domuncula. in 96-well plates, the effects of nutritional factors including glutamine, pyruvate, iron citrate, silicon, rpmi 1640, and marine broth 2216 on the viable cell density were examined in primary cell culture of s. domuncula 36 h after inoculation. ferric iron (fe3+) and pyruvate were found to significantly improve cell viability in a dose-dependent manner. silicon and glutamine showed limited improvements at certain concentrations. the supplement of rpmi 1640 and marine broth 2216 did not increase cell viability. as a result, several improved media able to maintain higher cell viability in a short-term culture of primary sponge cells could be formulated.

Ethylene regulation of apoplastic invertase expression in autotrophic cells of Chenopodium rubrum

Abstract: Physiological concentrations of ethylene in the growth medium of autotropic suspension culture Chenopodium rubrum L. cells reduced the activity of cell wall bound invertase by 25 – 47%, compared to controls. Northern blot analysis using homologous probe binding to total RNA preparations revealed that reduction in specific activity was paralleled by repression of the corresponding gene.

Contribution of hydrogenase 2 to stationary phase H2 production by Escherichia coli during fermentation of glycerol

Abstract: Escherichia coli has four hydrogenases (Hyd), three genes of which are encoded by the hya, hyb, and hyc operons. The proton-reducing and hydrogen-oxidizing activities of Hyd-2 (hyb) were analyzed in whole cells grown to stationary phase and cell extracts, respectively, during glycerol fermentation using novel double mutants. H2 production rate at pH 7.5 was decreased by ~3.5- and ~7-fold in hya and hyc (HDK 103) or hyb and hyc (HDK 203) operon double mutants, respectively, compared with the wild type. At pH 6.5, H2 production decreased by ~2- and ~5-fold in HDK103 and HDK203, respectively, compared with the wild type. At pH 5.5, H2 production was reduced by ~4.5-fold in the mutants compared with the wild type. The total hydrogen-oxidizing activity was shown to depend on the pH of the growth medium in agreement with previous findings and was significantly reduced in the HDK103 or HDK203 mutants. At pH 7.5, Hyd-2 activity was 0.26 U (mg protein)(-1) and Hyd-1 activity was 0.1 U (mg protein)(-1). As the pH of the growth medium decreased to 6.5, Hyd-2 activity was 0.16 U (mg protein)(-1), and Hyd-1 was absent. Surprisingly, at pH 5.5, there was an increase in Hyd-2 activity (0.33 U mg protein)(-1) but not in that of Hyd-1. These findings show a major contribution of Hyd-2 to H2 production during glycerol fermentation that resulted from altered metabolism which surprisingly influenced proton reduction.

Induction of Enterococcal L-Forms by the Action of Lysozyme

Abstract: Suspensions of enterococci were treated with lysozyme in the presence of osmotic stabilizers. The resulting osmotically fragile bodies prepared from Streptococcus faecium strain F24 and S. faecalis strain E1 gave rise to L-forms under optimal osmotic and nutritional conditions for treatment and subsequent growth. The most critical component of the growth medium, to obtain maximum yields, was the nature and concentration of the added salt. The two most effective salts were sodium chloride and ammonium chloride in the range of 2 to 3% (w/v) added to a suitable agar base. Ammonium chloride was more versatile, because it could be used with either sucrose or polyethylene glycol 4000 as the osmotic stabilizer for preparation and dilution of the osmotically fragile bodies. Sodium chloride would not consistently support growth of S. faecium F24 as L-forms when polyethylene glycol 4000 was used as the osmotic stabilizer during lysozyme treatment. Time-course studies of concurrent cell wall removal and L-form induction suggested that maximal induction required only cell wall damage rather than complete wall removal. This method for induction of L-forms from a suspension of enterococci is a significant improvement over other presently known methods.

Suppression of methionine synthesis in Escherichia coli by growth in the presence of this amino acid.

Abstract: SUMMARY: The ability of washed suspensions of Escherichia coli Y44 (which requires histidine and p-aminobenzoic acid for growth) to synthesize methionine from homocysteine was decreased almost to zero when the organism was harvested from a growth medium containing methionine itself. There was a similar effect, though in no case quite so severe, with eleven other strains of the organism. In further experiments with strain Y 44 the effect was found to be specific to methionine; the presence during growth of no other amino acid tested decreased subsequent synthesis by more than 20%. Ability to synthesize methionine was lost and regained on single successive cultivations in the presence and absence of the amino acid; there was also no evidence from viable counts on agar media ± methionine for a genetic change. ‘Inactive’ organisms (methionine-grown) were not activated by changing the nature of the precursor of the methyl group nor by adding heated extracts of yeast or of ‘active’ organisms. There was no evidence that ‘inactive’ organisms produced an inhibitor of methionine synthesis. It is concluded that growth with methionine leads to the non-production of an enzyme(s) concerned directly in the addition of the one-carbon unit to homocysteine.