Biogenesis of auxin in the coleptile of a semi-brachytic barley, uzu

The coleoptile of a semi-brachytic barley, uzu(Hordeum vulgareL. cv. Akashinriki), elongated ca 1/2 as much as the coleoptileof the contrasting normal form which is isogenic excepting theuz gene. This retarded growth of the uzu coleoptile, as comparedto the normal coleoptile, is not due to changes in the rateof basipetal transport of auxin, neither to the destructionof auxin during transport, nor to sensitivity to auxin. Furthermore,less of the extractable and bound auxins were found in the uzu(uzuz)coleoptile than in the normal(UZUZ)coleoptile, suggesting thatthe retarded growth of uzu coleoptile may be due to less auxinproduction. Apical tips of the normal coleoptile grown under sterile conditionsresponded to both tryptophan and tryptamine, but uzu coleoptiletips responded only to tryptamine. Thus, growth retardationof the uzu coleoptile may be due to lower activity of the enzymewhich converts tryptophan to tryptamine in the uzu coleoptile. (Received August 20, 1973; )     

Functional interaction of free polyribosomes with the membrane of the endoplasmic reticulum in a cell-free protein-synthesizing system from plasmacytoma X5563

In cell-free protein synthesis by the murine plasmacytoma X5563, which had become a nonproducing mutant, mixed systems with free polyribosomes and mirosomes incorporated ¹⁴C-amino-acid into protein 3–8 times greater than the sum of the incorporations in the individual system irrespective of S-100 concentrations. This enhancement was inhibited by lecithinase A and was markedly reduced at high KCl concentrations. Smooth endoplasmic membranes had more stimulatory activity than rough endoplasmic membranes. The results indicate that the membrane of the endoplasmic reticulum and free polyribosomes interact in the cell-free protein-synthesizing system, resulting in the enhancement of protein synthesis.     

Anion-dependent changes of energy transfer in chloroplasts I. Effects of Tris salts on electron flow and phosphorylation

Washing spinach chloroplasts with high-concentration Tris-saltbuffers induced various types of anion-dependent changes inthe electron flow and photophosphorylation in chloroplasts. Tris-HCl buffer caused enhancement of NADP photoreduction andinhibition of phosphorylation. Tris-HNO₃ buffer, on the otherhand, caused inhibition of both electron flow and phosphorylationand decreased trypsin-activated Ca²+-dependent ATPase activity.Tris-H₂SO⁴ and Tris-H₃PO⁴ buffers, however, had no effect onthe rates of electron flow and photophosphorylation. Determination of the presence of the coupling factor (as measuredby ATPase activity) revealed a normal enzyme activity levelin chloroplasts washed with Tris-HCl or Tris-H₂SO⁴ buffer. Removalof the coupling factor by EDTA from chloroplasts washed withTris salts inhibited phosphorylation severely. Phosphorylationactivity could be partially restored by reconstitution withthe coupling factor in die presence of Mg²+. In addition to their different effects on electron flow, Tris-HCland Tris-HNO₃ induced a marked decrease in phosphorylative activityitself. The much decreased rate of phosphorylation can be explainedby the release of the coupling factor and by damage to the high-energystate generating mechanism by Tris-HNO₃-washing and by modificationof the coupling factor in the case of Tris-HCl-washing. ¹Present address: Biology Department, College of Science andEngineering, Ryukyu University, Naha, Okinawa. Japan. (Received June 27, 1972; )