Photodynamic induction of a bacterial cell surface polypeptide

Abstract

The photodynamic action of several dyes on cells of a bacterium, tentatively identified as a species of Arthrobacter, resulted in remarkable stimulation of synthesis of a polypeptide 21,000 daltons in mass. This polypeptide resides on the cell surface and can be solubilized by sodium dodecyl sulfate without lysis of the cells. Chlorophyllin and rose bengal are effective in inducing synthesis of the polypeptide in proportion to their ability to sensitize the photooxidation of histidine. Etiolated cells of the alga Chlamydomonas reinhardtii y-1 excrete a substance into the medium that also sensitized the photoinduction of the polypeptide.

Kinetics of accumulation of a photodynamically induced cell-surface polypeptide in a species of Arthrobacter

“…A set of environmental conditions has been found that causes induction of synthesis of a bacterial cell-surface polypeptide (14). This induction, observed with a species of Arthrobacter, requires light, oxygen, and a photosensitizing dye.…”

“…MATERIALS AND METHODS Growth of cells. Arthrobacter cells were maintained on agar containing a defined medium in association with Chlamydomonas cells, as described previously (14). After transfer of the mixture to agar medium supplemented with 0.1% yeast extract, the bacterial cells were isolated as the result of their more rapid rate of growth.…”

SIMILARITIES IN THE INDUCTION OF SYNTHESIS OF A CELL‐SURFACE POLYPEPTIDE IN Arthrobacter sp. BY NEAR‐UV IRRADIATION and PHOTODYNAMIC CONDITIONS

“…The Arthrobacter cells used in these experiments were discovered because they synthesized large amounts of a specific polypeptide in response to very mild photodynamic conditions (Stegeman and Hoober, 1975;Hoober, 1977). This unusual behavior prompted us to further examine this phenomenon and to attempt to understand its mechanism.…”

“…After mercaptoethanol (4 P I ) was added to each, the samples were heated in boiling water for 2 min. This treatment solubilized surface proteins but caused minimal lysis of the cells (Hoober, 1977). Electrophoresis on slab gels in the presence of SDS and subsequent radioautography of dried gels were performed as described before (Hoober and Franzi, 1980).…”

“…furthermore, that 10 p M hemin inhibited induction in visible light mediated by neutral red and acriflavin, other cationic dyes, but did not inhibit induction sensitized by rose bengal, an anionic dye. Induction mediated by the porphyrin chlorophyllin (Hoober. 1977) also was not inhibited by hemin (results not shown).…”