%0 Journal Article %A Bovarnick, Joan G. %A Chang, Sung-Wen %A Schiff, J. A. %A Schwartzbach, S. D. %T Events Surrounding the Early Development of Euglena Chloroplasts: Experiments with Streptomycin in Non-dividing Cells* %D 1974 %J Microbiology, %V 83 %N 1 %P 51-62 %@ 1465-2080 %R https://doi.org/10.1099/00221287-83-1-51 %I Microbiology Society, %X SUMMARY: The concentration of streptomycin (Sm) which selectively inhibits light-induced chloroplast development in non-dividing Euglena is the same as that which induces the loss of green-colony forming ability in dividing organisms. This concentration of Sm has no effect on division or viability. Chlorophyll synthesis is insensitive to streptomycin for the first 12 h of development but is strongly inhibited after this time. Between 72 and 96 h after the beginning of chloroplast development, Sm-treated organisms contain 10 % of the chlorophyll and 24 % of the carotenoids of algae developing in the absence of the antibiotic. The chlorophyll-to-carotenoid ratio in treated organisms at 72 to 96 h is 0ยท9, the same as is found at 12 h for organisms developing in the absence of Sm. In the presence of streptomycin, Euglena never develops the ability to fix CO2 photosynthetically, although CO2 fixation after 12 h of development in the absence of the antibiotic can be readily detected. At 12 h of chloroplast development the following parameters are at comparable levels in Sm-treated and untreated organisms: the bound forms of chlorophyll, concentration of cytochrome 552, the activities of ribulose diphosphate carboxylase, NADP-triose phosphate dehydrogenase, the enzymes converting ribose-5-phos- phate to ribulose diphosphate, and photosystem II activity measured as dye reduction. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-83-1-51