PubMed Health⌕ Search

Biomedical subjects

A KELNER

Publications and source records attributed to A KELNER.

8 recordsLinked to original sources
PubMed1964

CORRELATION BETWEEN GENETIC TRANSFORMABILITY AND NON-PHOTOREACTIVABILITY IN BACILLUS SUBTILIS.

Kelner, Albert (Brandeis University, Waltham, Mass.). Correlation between genetic transformability and nonphotoreactivability in Bacillus subtilis. J. Bacteriol. 87:1295-1303. 1964.-Photoreactivation after ultraviolet irradiation was studied in the transformable Bacillus subtilis SB-1. Moderate photoreactivability (maximal increase in survival due to photoreactivating light, five- to tenfold) was found in (i) noncompetent vegatative cells produced in Brain Heart Infusion broth, and in (ii) the total viable cells of a competent culture grown in special competency-producing medium and tested either just before or after transformation with deoxyribonucleic acid. However, no, or only trace, photoreactivation (maximal increase in survival, 1.5- to 2-fold) was found in that fraction of a competent culture actually able to be transformed. This nonphotoreactivability was a temporary property of transformable cells, since clones derived from them were normally photoreactivable. Nonphotoreactivability is not explained by injury to transformants caused by photoreactivating light, although transformants are killed by very large doses of light. The findings in B. subtilis strengthen the idea that transformability is generally correlated with nonphotoreactivability.

Bacillus subtilis↗
PubMed1951

Action spectra for photoreactivation of ultraviolet-irradiated Escherichia coli and Streptomyces griseus.

Action spectra for photoreactivation (light-induced recovery from ultraviolet radiation injury) of Escherichia coli B/r and Streptomyces griseus ATCC 3326 were determined. The spectral region explored was 365 to 700 mmicro. The action spectrum for S. griseus differed from that for E. coli, indicating that the chromophores absorbing reactivating energy in the two species were not the same. Reactivation of S. griseus occurred in the region 365 mmicro (the shortest wave length studied) to about 500 mmicro, with the most effective wave length lying near 436 mmicro. This single sharp peak in the spectrum at 436 mmicro suggested the Soret band typical of porphyrins. Reactivation of E. coli occurred in the region 365 to about 470 mmicro, with the most active wave length lying near 375 mmicro. The single, non-pronounced peak near 375 was probably not due to a Soret band, and the identification of the substance absorbing reactivating light in E. coli is uncertain. In neither species was the region 500 to 700 mmicro active. The implications of these action spectra and their differences are discussed.

Actinomyces↗