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.

A process for the reduction of the nucleic acid content of a fungus imperfectus

Abstract: The RNA content of Fungi Imperfecti, for example Fusarium graminearum can be reduced with low protein loss by heating it in the presence of its growth medium to a temperature above 68 °C and separating growth medium from it.

Mammalian cell transformation induced by chromium(VI) compounds in the presence of nitrilotriacetic acid.

Abstract: We used a soft agar assay on cultured Syrian hamster fibroblasts to determine the ability of nitrilotriacetic acid (NTA) and Cr(VI) compounds to induce malignant cell transformation. Induction of extended anchorage-independent growth was detected in BHK 21/c13 cells by scoring colonies of transformed cells visible to the naked eye 20-25 d after plating in growth medium containing agar. Survival was determined by plating cells in liquid medium without agar and by counting the number of macroscopic colonies after 7-10 d. Mitomycin C and 4-nitroquinoline 1-oxide were used as reference direct transforming agents, with clearly positive results. In our hands no increase of the spontaneous transformation rate of BHK cells was induced by NTA concentrations ranging from 2 X 10(-3) to 10(-2) M, although the survival index was significantly reduced above 4 X 10(-3) M NTA. Two Cr(VI) compounds, K2Cr2O7, which is highly soluble in water, and CaCrO4, which is partially soluble, were tested in the soft agar assay either in the absence or in the presence of NTA. When used alone, both compounds behaved as positive transforming agents. NTA increased 4 or 10 times the cytotoxicity and the transforming activity of CaCrO4 and K2Cr2O7, respectively. As the amounts of soluble Cr(VI) detectable in the K2Cr2O7 and CaCrO4 solutions were not increased in the presence of NTA, a synergistic interaction between NTA and soluble Cr(VI) is inferred.

Continuous culture of mixed sediment bacteria in the presence of mercury

Abstract: Continuous culture methods were used to isolate bacteria from sediment from Lake Ontario. These mixed cultures were grown in chemostats at different dilution rates and the glucose concentration in the culture vessel, the optical density, the biomass of cells, and the number and types of bacteria present were monitored for at least 80 generations. Two bacterial types, bothPseudomonas spp., were present at all dilution rates in significant quantities. The mixed cultures exhibited a reciprocal relationship between dilution rate and biomass (and number of bacteria). When Hg was added to the growth medium at a concentration of 5 mg 1−1, the bacteria tolerated that concentration at a dilution rate of 0.117 h−1 substantial changes in the population were noted at a concentration of 10 mg 1−1 Hg. One of the isolates from the mixed culture would not grow at 5 or 10 mg 1−1 of Hg in continuous culture at a dilution rate of 0.066 h−1. In the mixed continuous culture the same isolate showed only minimal response to a Hg concentration of 10 mg 1−1.