Effect of auxin and other hormones on the metabolic response to wounding in sweet potato roots

In roots of sweet potato (Ipomoea batatas Lam. cv. Kokei 14),the metabolic response to wounding was remarkable only in theproximal side. We assumed that the polarity resulted from apolar movement of indole-3-acetic acid (IAA) produced in thecut surface (8). As the metabolic response was slight in thedistal side, the effect of IAA and the other plant hormoneson the development of various enzyme activities was examinedin this side. Increases in activities of L-phenylalanine ammonia-lyase,acid invertase, NADPHa₂ : cytochrome c oxidoreductase, peroxidase,cytochrome c : O₂ oxidoreductase and o-diphenol oxidase, whichdeveloped in response to wounding, were stimulated by the treatmentwith IAA. Gibberellic acid had a stimulative effect on the developmentof only acid invertase activity. Abscisic acid and kinetin hadlittle effect. The results strongly support our hypothesis thatIAA plays an important role in the metabolic response to wounding. (Received September 29, 1979; )     

Production of anti-self-H-2 antibodies by C3D2F1 mice hyperimmune to L cell/L1210 hybrids and L1210 leukemia cells

During the course of immunization of (C3H × DBA/2)F₁ mice (genotype H-2^k/b) with L cell (H-2^k/k)/L1210 leukemia cell (H-2^d/d) hybrids and L1210 leukemia cells, some of them produced a good titer of anti-self-H-2 (H-2^d) antibodies. Antigens recognized by this anti-self-H-2 antiserum were shown to be controlled by the H-2K-IA-IB-IJ-IE subregions of the H-2^d but not H-2^k nor H-2^b haplotypes of parental as well as F₁ origins and to have a tissue distribution identical to that of class 1 H-2 (H-2K/D) antigens.     

Electrophoresis of mutant proteins in inherited diseases

The electrophoretic approaches for detection of mutant proteins in inherited diseases are briefly reviewed and discussed. Mutation of a protein, known to be associated with a specific inherited disease, is detected by immunoblotting, immunoprecipitation or enzyme staining, combined with various electrophoretic techniques. Some instrumental and technological devices for two-dimensional electrophoresis have been reported for the screening of mutant proteins in diseases of currently unknown etiology.     

Autophagy in yeast demonstrated with proteinase-deficient mutants and conditions for its induction

For determination of the physiological role and mechanism of vacuolar proteolysis in the yeast Saccharomyces cerevisiae, mutant cells lacking proteinase A, B, and carboxypeptidase Y were transferred from a nutrient medium to a synthetic medium devoid of various nutrients and morphological changes of their vacuoles were investigated. After incubation for 1 h in nutrient-deficient media, a few spherical bodies appeared in the vacuoles and moved actively by Brownian movement. These bodies gradually increased in number and after 3 h they filled the vacuoles almost completely. During their accumulation, the volume of the vacuolar compartment also increased. Electron microscopic examination showed that these bodies were surrounded by a unit membrane which appeared thinner than any other intracellular membrane. The contents of the bodies were morphologically indistinguishable from the cytosol; these bodies contained cytoplasmic ribosomes, RER, mitochondria, lipid granules and glycogen granules, and the density of the cytoplasmic ribosomes in the bodies was almost the same as that of ribosomes in the cytosol. The diameter of the bodies ranged from 400 to 900 nm. Vacuoles that had accumulated these bodies were prepared by a modification of the method of Ohsumi and Anraku (Ohsumi, Y., and Y. Anraku. 1981. J. Biol. Chem. 256:2079-2082). The isolated vacuoles contained ribosomes and showed latent activity of the cytosolic enzyme glucose-6-phosphate dehydrogenase. These results suggest that these bodies sequestered the cytosol in the vacuoles. We named these spherical bodies "autophagic bodies." Accumulation of autophagic bodies in the vacuoles was induced not only by nitrogen starvation, but also by depletion of nutrients such as carbon and single amino acids that caused cessation of the cell cycle. Genetic analysis revealed that the accumulation of autophagic bodies in the vacuoles was the result of lack of the PRB1 product proteinase B, and disruption of the PRB1 gene confirmed this result. In the presence of PMSF, wild-type cells accumulated autophagic bodies in the vacuoles under nutrient-deficient conditions in the same manner as did multiple protease-deficient mutants or cells with a disrupted PRB1 gene. As the autophagic bodies disappeared rapidly after removal of PMSF from cultures of normal cells, they must be an intermediate in the normal autophagic process. This is the first report that nutrient-deficient conditions induce extensive autophagic degradation of cytosolic components in the vacuoles of yeast cells.     

Purification and properties of extracellularβ-fructofuranosidases fromAureobasidium sp. ATCC 20524

Summary Two extracellular -fructofuranosidases (E-1 andE-2) fromAureobasidium sp. ATCC 20524, producing 1-kestose (1^F--fructofuranosyl-sucrose) from sucrose, were purified to homogeneity. Molecular weights of the enzymes were estimated to be about 304000 (E-1) and 315000 (E-2) Da by gel filtration. The enzymes contained 33% (w/w) (E-1) and 27% (w/w) (E-2) carbohydrate. TheK _m values for sucrose ofE-1 andE-2 andE-2 were 0.34 and 0.28 M, respectively. were 0.34 and 0.28 M, respectively. The enzymatic profiles of these enzymes were almost identical to intracellular enzymesP-1 andP-2 except for the differences in carbohydrate content andK _m values ofE-2 andP-2.     

Application of enzyme-linked immunosorbent assay for mass examination of strongyloidiasis in okinawa, Japan

The enzyme-linked immunosorbent assay was tested to evaluate whether it could be applicable in screening for mass examination of strongyloidiasis. A total of 2906 inhabitants in three areas (858 in Gushikawa Village, 849 in Nakazato Village and 1199 in Sashiki Town) were screened by the enzymatic assay and approximately 11–30% (11.8% in Gushikawa, 17.0% in Nakazato and 27.7% in Sashiki) were considered to be antibody positive. In the parasitological follow-up examinations of those who were antibody positive, actual infection was found in more than half (51%) the subjects. The overall infection rates estimated from the results reached 5.8% in Gushikawa, 9.1% in Nakazato and 14.0% in Sashiki (mean = 10.4%). The infection rates were significantly higher than those in previous surveys conducted in the same areas. The ELISA technique was found to be useful for strongyloidiasis screening and for seroepidemiological purposes in Okinawa.     

S-(1,2-dicarboxyethyl)glutathione and activity for its synthesis in rat tissues

The contents of S-(1,2-dicarboxyethyl)glutathione (DCE-GS) in several tissues of rat were determined by HPLC. The peptide was present at concentrations (nmol/g tissue) of 119 in lens, 71.6 in liver, and 27.4 in heart. It was, however, not detected in spleen, kidney, cerebrum, or cerebellum. In rat liver, DCE-GS was located primarily in the cytosolic fraction. The substrates for the enzymic synthesis of DCE-GS were GSH and L-malate. In rats, the DCE-GS-synthesizing activity was found to be highest in the liver and in the cytosol of rat liver subcellular fractions. The DCE-GS-synthesizing enzyme was partially purified from rat liver cytosolic fraction by ammonium sulfate fractionation, Phenyl Superose chromatography, hydroxyapatite chromatography, and gel filtration. The molecular mass of the enzyme was estimated to be 53 kDa by gel filtration and SDS-PAGE, showing it to be a monomeric protein. The Km values for GSH and L-malate were 2.3 and 4.0 mM at 37 degrees C, respectively. The enzyme did not utilize 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, p-nitrophenyl bromide, trans-4-phenyl-3-buten-2-one, or p-nitrobenzyl chloride, which were substrates for previously characterized glutathione S-transferases. The isolated enzyme preparation showed no fumarase activity, which supported the conclusion that the formation of DCE-GS was not the result of a nonenzymic reaction following the synthesis of fumarate from L-malate by the isolated enzyme. The N-terminal amino acid of this polypeptide was presumably blocked since no sequence was obtained by automatic sequencing after electro-blotting onto a siliconized-glass fiber (SGF) sheet.     

Inhibition of platelet aggregation by S-(1,2-dicarboxyethyl)glutathione, intrinsic tripeptide in liver, heart, and lens

S-(1,2-Dicarboxyethyl)glutathione (DCE-GS) found in animal tissues or baker's yeast showed strong inhibitory effects on blood coagulation and platelet aggregation. The inhibitory effect of blood coagulation was almost the same as those of EDTA, oxalate, and citrate. DCE-GS did not show chelating activity. As for ADP- or thrombin-induced platelet aggregations, DCE-GS exerted a potent effect on the secondary aggregation, while it was less active in the primary aggregation. DCE-GS gave a distinct lag period in the time course of the secondary aggregation induced by collagen and inhibited most strongly the aggregation induced by arachidonic acid compared with those elicited by ADP, thrombin, and collagen. The peptide, however, did not inhibit the platelet aggregation induced by 12-O-tetradecanoylphorbol-13-acetate. Although both DCE-GS and EDTA inhibited the platelet aggregation which was triggered by ADP, their inhibitory manners were entirely different.     

Hydrogen exchange kinetics of nucleic acids: Double and triple helices with Hoogsteen-type basepairs

The kinetics of hydrogen-tritium exchange reaction have been followed by a Sephadex technique of a double-helical poly(ribo-2-methylthio-adenylic acid)·poly(ribouridylic acid) complex with the Hoogsteen-type basepair. Only one hydrogen in every 2-methylthio-adenine·uracil basepair has been found to exchange at a measurably slow rate, 0.023 s^?1 (at 0°C), which is, however, much greater than that for a double-helix with the Watson-Crick type A·U pair. The kinetics of hydrogen-tritium exchange were also examined by triple-helical poly(rU)·poly(rA)·poly(rU) which involves both the Watson-Crick and Hoogsteen basepairings. Here, three hydrogens in every U·A·U base triplet have been found to exchange at a relatively slow rate, 0.0116 s^?1 (at 0°C). The kinetics of hydrogen-deuterium exchange reactions of these polynucleotide helices have also been followed by a stopped-flow ultraviolet absorption spectrophotometry at various temperatures. On the basis of these experimental results, the mechanism of the hydrogen exchange reactions in these helical polynucleotides was discussed. In the triple helix, the rate-determining process of the slow exchange of the three (one uracil-imide and two adenine-amino) hydrogens is considered to be the opening of the Watson-Crick part of the U·A·U triplet. This opening is considered to take place only after the opening of the Hoogsteen part of the triplet.     

Effects of Phosphate in Medium on Protein Secretion in a Protein-Producing Bacterium, Bacillus brevis 47

Bacillus brevis 47 secreted up to 1 mg of protein per ml in a chemically defined medium, depending on phosphate concentration. The composition of exoproteins was altered quantitatively by the concentration of external phosphate. Morphologically, B. brevis 47 showed a distinct three-layered cell wall structure and shed the outer two layers during growth.