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Hong, Soon Woo, Hah, Yung Chil (Dept. of Botany. Seoul National University), and Park, Sang Yoon(Dept. of Biology, Sung Kyun Kwan University): The Studies on effects of alanine and glycine in oxygen consumption of U-V irradiated Neurospora. The effect of ultraviolet light on living organisms have been studied by many physiologists and radiobiologists. But few papers which are concerning the influence of ultraviolet light on the respiration of micro-organisms are published up to date. From the view point of physiological work, the authors have attempted to study the effects of ultraviolet light on Neurospora respiration. Especially exogenous and endogenous respiration are more or less complehensively studing in this experiment. Neurospora Korean wild type which is obtained from Dept. of Microbiology, the Scientific Research Institute M.N.D., are used in this ecperiment. These materials growing in an agar plate are exposed to Matzuda fermicidal ultraviolet lamp for 10, 15, 20, 80 and 40 seconds. And then, the materials which are washed with pH 5.8 phosphate buffer are resuspended in the same buffer solution. O₂uptakes of those organisms in this experiment are determined by Warburg manometer standard method throughout first 1 hour to last 14 hours; endogenous respiration are measured in the pH 5.8 buffer solution and exogenous in the same buffer added with 0.1, 0.5 and 1.0 percent alanine and glycine. In this experiment, the authors have observed that there are marked inhibition of ultraviolet light on Neurospora endogenous respiration which are shown as like log phase curve as the survival curve. Strictly speaking, in endogenous respiration of irradiated Neurospora for 10 and 15 seconds there are inhibition slightly, but the strong irradiation such as 20, 30 and 40 seconds do greatly. In the case of exogenous respiration, we calculated the exogenous respiration rates of Neurospora being added with alanine and glycine as substrates. Though the materials added with alanine even if low concentrations, do effectively stimulate the exogenous respiration of irradiated one, all those rates in comparison with unirradiated Neurospora’s exogenous respiration rates are volumetrically inhibited. The exogenous O₂uptakes of 10 and 15 seconds irradiation are more stimulated by 0.1 and 0.5% alanine than 1.0% of alanine. However, in the case of 20, 30 and 40 seconds irradiation that are stimulated by high concentration, of alanine as 1.0% than low. Adding glycine described above concentration, the exogenous, respiration of irradiated Neurospora are effectively disrupted by increasing its concentration. According to those facts described above, as small an amount of photons are passing through the cells, endogenous respiration of them would be inhibited and their curves are shown log phase which results are similar to the survival curve reviewed by Lindegren, (29). But exogenous respiration shows slight effect of stimulation in low doses of irradiation. Adding the amino acid of glycine into cell suspensions, all concentraion of glycine, we presume that it might inhibit the action of the exogenous respiratory enzymes.
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