猕猴桃种质资源保存及育种研究

收集保存猕猴桃属植物３５种或变种、变型,并将它们分为抗寒?喜凉、喜温３种类型。从保存的中华猕猴桃优株中系统选育出“武植２号”、“武植３号”２个优良品种。以中华猕猴桃为母本,毛花猕猴桃为父本进行种间杂交,从杂种Ｆ１代中培养出“江山娇”、“满天星”、“重瓣”３个具有园艺观赏价值的优良株系。这些研究工作为猕猴桃种质资源的保存及新品种的培育奠定了工作基础。     

Mechanism of Action of Lycoricidinol, a Plant Growth Inhibitor Isolated from Lycoris radiata Herb.

We studied the action mechanism of lycoricidinol, a plant growthinhibitor isolated from Lycoris radiata Herb. Lycoricidinolinhibited protein synthesis in mung bean hypocotyls, but notRNA synthesis. Protein synthesis in Escherichia coli was notaffected by the inhibitor. Results of in vitro translation experimentswith the wheat germ system and the E. coli system indicatedthat lycoricidinol inhibited only eukaryotic but not prokaryotictranslation. Use of specific inhibitors of initiation and polypeptidechain elongation of polypeptide synthesis revealed that chainelongation was inhibited by lycoricidinol. ¹Permanent address: Department of Biology, Yonsei University,Seoul 120, Korea. (Received September 30, 1983; Accepted December 28, 1983)     

Effect of nutrient variations on growth and brefeldin A formation inCurvularia lunata

The highest level of secreted brefeldin A was present in glucose-grown cultures, intermediate levels in glucose-fructose, and xylose cultures and low levels in fructose- and galaotose-grown cultures ofCurvularia lunata. The biomass decreased from glucose, fructose, xylose, glucose-fructose to galactose cultures. Brefeldin A levels and mycelial yields were low in citrate-, gluconate-, and succinate-grown cultures. Inorganic phosphate-limited cultures supported a high level of brefeldin A. Intermediate levels were present in trace elements-, and inorganic phosphate-trace elements-limited cultures.     

Covalent structure of collagen: amino acid sequence of cyanogen bromide peptides from the amino-terminal segment of type III collagen of human liver

Human liver type III collagen was prepared by limited pepsin digestion, differential salt precipitation, and carboxymethylcellulose chromatography. Cyanogen bromide digestion of purified type III collagen chains yielded nine distinct peptides. Three peptides, alpha1(III)-CB3, alpha1(III)-CB7, and alpha1(III)-CB6, were isolated by carboxymethylcellulose chromatography and Sephadex G-50 SF gel filtration. Automated Edman degradation together with selective hydroxylamine cleavage and chymotrypsin and trypsin digestion enabled determination of their complete amino acid sequence. Compared with type I collagen, the data show tentative homology of alpha1(III)-CB3 with alpha1(I)-CB1, alpha1(I)-CB2, and alpha1(I)-CB4; alpha1(III)-CB7 with alpha1(I)-CB5; and alpha1(III)-CB6 with the amino-terminal portion of alpha1(I)-CB8. Close interspecies homology was found between the sequences presented here with 90 residues of alpha1(III)-CB3 and 26 of alpha1(III)-CB8 of calf aorta. The present study establishes the amino acid sequence of 229 residues near the amino terminus or nearly one-quarter of the type III collagen chains. The disaccharide, Glc-Gal, was convalently bound to hydroxylysine at a position corresponding to the same location in the alpha1(I) chain.     

Nitrogen catabolite repression in a glutamate auxotroph of Saccharomyces cerevisiae

The biosynthesis of asparaginase II in Saccharomyces cerevisiae is subject to nitrogen catabolite repression. In the present study we examined the physiological effects of glutamate auxotrophy on cellular metabolism and on the nitrogen catabolite repression of asparaginase II. Glutamate auxotrophic cells, incubated without a glutamate supplement, had a diminished internal pool of alpha-ketoglutarate and a concomitant inability to equilibrate ammonium ion with alpha-amino nitrogen. In the glutamate auxotroph, asparaginase II biosynthesis exhibited a decreased sensitivity to nitrogen catabolite repression by ammonium ion but normal sensitivity to nitrogen catabolite repression by all amino acids tested.     

Genetic structure of the Queckchi Indians. Dental microdifferentiation.

Nine oral morphologic characters were investigated. Their frequencies are compared with those published for other populations. The possibility of using such characters to estimate genetic distance between populations is discussed and the conclusion is reached that, although previous studies have suggested this to be a valid approach, further studies testing this subject are needed.     

Limits of artificial selection under unbalanced mating systems

Summary The influence of unbalanced mating systems — factorial mating (FM) and random loss of families after a full diallel crossing (RS) — on the ultimate probability of gene fixation (u()) and the time required to fix or lose a gene (t()) are investigated. The average u() of these systems is smaller than that of random mating, and the range of u() for a given initial parental genotype combination is very large (close to one for most initial genotypic combinations). The average u() of different parental genotypic combinations of a given gene frequency are different. These systems accelerate the t().This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain     

A fluorescent derivative of ribosomal protein S18 which permits direct observation of messenger RNA binding.

70 S Escherichia coli ribosomes were reacted with the fluorescent dye N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonic acid for 10 min under mild conditions. The resulting ribosomes were fully active. 30 S subunits isolated from these particles were also fully active. They contain approximately 0.7 eq of fluorescent dye. Nearly all of it is attached to protein S18. Competitive reaction with N-ethylmaleimide implies that the fluorescent dye is located at cysteine 10 of the protein. The labeled 30 S particles will recombine with 50 S subunits to form stable 70 S particles. Thus the procedures we have developed allow the large scale preparation of an active fluorescent conjugate of the 70 S ribosome. The fluorescence of the 70 S particles is sensitive to the binding of mRNA, showing both quenching and a shift in emission spectra. Thus it affords a simple way to quantitate mRNA binding directly. In pilot studies without tRNA, the binding constant of the initiation triplet codon adenylyl-(3' leads to 5')-uridylyl-(3' leads to 5')-guanosine to 70 S ribosome was found to be an order of magnitude larger than that of polyuridylic acid.     

Carnitine uptake and fatty acid utilization by diploid cells aging in culture

Uptake of carnitine by cultured human fetal lung flbroblasts (WI-38 and IMR-90) and by smooth muscle cells from calf aorta and from human uterus was found to be temperature dependent and saturable. IMR-90 cells showed an apparent K_m of 6–8 μM and a V of 21–28 pmol/h/10⁶ cells for l-carnitine. Transport was abolished by N-ethylmaleimide and was inhibited variably by octanoyl-d-carnitine, d-carnitine, and carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Although WI-38 and IMR-90 cells accumulate lipids as they age in culture, they take up carnitine as rapidly as do smooth muscle cells of aorta and uterus that do not exhibit such accumulation. Comparison of the rates of carnitine uptake by IMR-90 fibroblasts during the logarithmic phase of growth shows no difference between “young” and “old” cultures. In contrast, when confluent or postconfluent monolayers were compared and uptake expressed as a function of cell number, cells grown from late passages took up carnitine more rapidly than did cells grown from early passages. However, when account was taken of cell size, and carnitine expressed as a function of cell volume, the differences in carnitine uptake between early and late passages were no longer apparent for the confluent or postconfluent monolayers examined. Moreover, late passage fibroblasts took up and oxidized radioactive palmitate at least as rapidly as did cells from early passages. Our results suggest that accumulation of lipid in aging fibroblasts is not due to decreased carnitine uptake or fatty acid oxidation.     

氦氖激光对绵羊精清中酶活性效应的研究

本文研究结果表明低剂量的氦氖激光可以提高绵羊精清中GOT和LDH酶的活性,并对其机制作了初步的探讨。