• Microbiology and Biotechnology Letters
• /
• v.23 no.5
• /
• pp.556-558
• /
• 1995

A strain which showed cephalosporin C resistance and 7-aminocephalosporanic acid sensitivity was isolated from nature. Among the isolates, SS5 was sensitive to cephalosporin C, penicillin G, ampicillin, 7-aminocephalosporanic acid, 6-aminopenicillanic acid, and 7-aminodeacetoxy cephatosporanic acid at concentrations of 1,000 $\mu $g/ml, 2,000 $\mu $g/ml, 3,000 $\mu $g/ml, 30 $\mu $g/ml 100 $\mu $g/ml and 100 $\mu $g/ml, respectively. But SS5 was sensitive at very low concentration of chloramphenicol, kanamycin, neomycin, streptomycin and tetracycline. Since SS5 was sensitive to 7-ACA (30 $\mu $g/ml) and didn't have $\beta $-lactamase activity on the cephalosporin C, SS5 could be useful as an indicator strain for the production of 7-ACA, which is an important precursor for the synthesis of many semisynthetic cephalosporins.

• Korean Journal of Microbiology
• /
• v.32 no.3
• /
• pp.202-207
• /
• 1994

A mutant strain PRM1 defective in light-activated heterotrophic growth was isolated from Synechocystis sp. PCC 6803. PRM1 could be grown at growth rate equivalent to Synechocystis 6803 under mixotrophic growth conditions. However, PRM1 could not be grown under light-activated heterotrophic conditions, in which a daily pulse of light for 5 min was given. These results suggest that PRM1 is not defective in heterotrophic metabolism, but in the transduction pathway of light signal essential to the growth. Plasmid patterns, absorption spectra of whole cells, and the exterior and interior structures of PRM1 were similar to those of Synechocystis 6803, except that PRM1 could not produce amorphous slime holding cells together.