Poly(U)-dependent polyphenylalanine and polytyrosine synthesis in vitro by a tRNATyr variant with an enzymatically altered anticodon, G-A-A

A variant of T. utilis tRNATyr containing a base substitution (psi----A) in the middle position of the anticodon has been constructed by enzymatic procedures in vitro. This variant is unique in that it can accept both tyrosine and phenylalanine. This tRNA was shown to be active in transferring both tyrosine and phenylalanine into polypeptides in a cell-free, poly (U)-directed translation system from yeast. This result gives further support to the adapter hypothesis since tyrosine, attached to the variant tRNATyr with an anticodon G-A-A, is incorporated into polypeptides in response to poly (U) message.     

The Incorporation of Farnesol-2-14C into Ipomeamarone

The survival of genetically engineered and wild-type Pseudomonas putida PpY101, that contained a recombinant plasmid pSR134 conferring mercury resistance, were monitored in andosol and sand microcosms. The survival of genetically engineered and wild-type P. putida was not significantly different in andosol. The population change of the two strains was dissimilar in andosol and sand. The survival of genetically engineered and wild-type P. putida strains was affected by the water content of andosol, and increased with the increment of the water content. The impact of the addition of genetically engineered and wild-type P. putida strains on indigenous bacteria and fungi was examined. Inoculation of both strains had no apparent effect on the density of indigenous microorganisms.     

Biosynthesis of Peroxidases in Sliced or Black Rot-Infected Sweet Patato Roots

The increment in peroxidase activity in response to cutting of sweet potato roots was inhibited by some inhibitors concerned in protein synthesis, RNA synthesis, and oxidative phosphorylation. The starch-gel electrophoretogram of the peroxidases from the tissue treated with the inhibitors was investigated with densitometer and compared with the corresponding electrophoretogram of the sliced tissue without the treatment. There was no prominent difference in the patterns between them, although activity of all peroxidase components detected on starch gel was weaker in the case of treated tissue. Cellular distribution of the peroxidases was studied on various fractions obtained by differential centrifugation. The activity was largely concentrated in the supernatant fraction, but it was also found in both mitochondrial and microsomal fractions, though in less amounts.     

Changes in Acid-soluble Nucleotides in Cut-injured Sweet Potato Root Tissue

ATP and ADP increased in cut-injured sweet potato root tissue during the 3 to 6-hr incubation period, and showed the maximum for the 9 to 18-hr, and 6 to 9-hr incubation periods, respectively, then decreased. ATP was present in the highest amount among ATP, ADP and AMP throughout the 72-hr incubation period, while AMP was in the lowest. Total acid-soluble nucleotides increased gradually, and showed the peak content at the 12-hr incubation period, and decreased thereafter. Adenine mononucleotides such as ATP, ADP and AMP occupied about 40 to 65% of total acid-soluble nucleotides.     

Occurrence of Peroxidases in Sweet Potato Infected by the Black Rot Fungus

Changes in the peroxidase activity and the patterns in sweet potato tissue infected by Ceratocystis fimbriata were investigated, by the method of starch-gel electrophoresis, DEAE-cellulose column chromatography and immunochemical analysis, compared with that in cut and healthy tissue. Time-course analysis of the increment of the total peroxidase activity also showed noticeable differences between diseased and cut tissues. The peroxidases in diseased and cut tissues were composed of four major and several minor components. Though electrophoretic analysis did not show so striking differences in the patterns of peroxidases between diseased and cut tissues, there were distinct differences in the ratio of activities of major peroxidase components between both tissues. Immunochemical works indicated that peroxidase A which showed the most prominent increase in diseased tissue was found to be formed in cut tissue though the amounts were appreciably small. The activity of peroxidase C in diseased tissue was not so high as seen in cut tissue.