EFFECT OF CAROTENE COMPOSITION ON RESISTANCE OF ALGAL CELLS TO UV-C RADIATION

We investigated resistance to UV-C radiation in mutants of the unicell ular green alga Chlamydomonas reinhardtii with different composition o f carotene isomers. Alteration of the ratio of alpha- and beta-isomers from 5:95-characteristic of cells of the K(+) wild type and A-20 muta nt-to 60:40 in the A-90 mutant and A-66-90 hybrid was accompanied by 1 .5- to 2.0-fold decline of cell resistance to action of UV-C radiation . On the other hand, the presence of beta- and zeta-isomers in a ratio close to 60:40 in the C-41 mutant was correlated with a 1.5-fold incr ease of cell resistance. The authors discuss the possible mechanism go verning involvement of carotene isomers in resistance of cells under c onditions of both dark growth and photoreactivation.