Uptake of high-density lipoprotein by Y-organs of the crab,cancer antennarius. II. formal characterization of receptor-mediation with isolated membranes

Y-organs are the ecdysial glands of crustaceans, responsible for synthesis and secretion of ecdysteroid hormones. For this purpose, the glands acquire cholesterol as obligate precursor entirely from circulating high-density lipoprotein (HDL). A preceding study provided evidence for the mechanism of acquisition: Y-organs take up cholesterol bound to HDL by an energy-requiring process, receptor-mediated absorptive endocytosis. The present study characterized the receptors involved utilizing isolated Y-organ membranes. HDL binding was saturable and specific; a dissociation constant (K_d) of 1.08 × 10^?7 M and a binding maximum at equilibrium (B_max) of 70 μg HDL protein/mg membrane protein, were obtained. Binding was decreased by protease and was dependent upon calcium. Y-organs are regulated negatively by a peptide hormone from the eystalks, molt-inhibiting hormone (MIH). Y-organ membranes from de-eyestalked crabs (MIH absent) exhibited the same K_d value as membranes from intact crabs, but a B_max 17% higher. Thus, MIH activity apparently does not change the binding affinity of HDL, but decreases the number of binding sites. These results agree with our previous findings that MIH depresses ecdysteroid synthesis in part by inhibiting cholesterol uptake. Generally, Y-organ cells appear to contain receptors for HDL that are of high affinity and high binding capacity, similar to the characteristics reported for the binding of insect HDL (vitellogenin) to fat bodies and oocytes. © 1995 Wiley-Liss, Inc.     

Molecular structure of the halogenated anti-cancer drug iododoxorubicin complexed with d(TGTACA) and d(CGATCG).

4'-Deoxy-4'-iododoxorubicin, a halogenated anthracycline derivative, is an anticancer agent currently under Phase II clinical trials. In preclinical studies, it has demonstrated significantly reduced levels of cardiotoxicity compared to currently employed anthracyclines. It also has modified pharmacological properties resulting in an altered spectrum of experimental antitumor activity. The iodine atom at the 4' position of the sugar ring reduces the basicity and enhances the lipophilicity of this compound as compared to related anthracycline drugs. We report here single crystal X-ray diffraction studies of the complexes of 4'-deoxy-4'-iododoxorubicin with the hexanucleotide duplex sequences d(TGTACA) and d(CGATCG) at 1.6 and 1.5 A, respectively. The iodine substituent does not alter the geometry of intercalation as compared to previously solved anthracycline complexes, but appears to markedly affect the solvent environment of the structures. This could have consequences for the interaction of this drug with DNA and DNA binding proteins in cells.     

四川地区幼儿和学龄前儿童的鼻部测量

本文报告１１１６例四川地区幼儿和学龄前儿童（２－７岁）鼻部９项指标的测量均数,性差及年龄发育特点。性差：仅鼻凹鼻底距４－６．５岁等少数指标部分年龄段男女性间出现显著性划异（男＞女）。此外各项指标的绝大多数年龄段男女性间无显著性差异。年龄发育：９项测量指标中７项的生长曲线随年产长而上升,数值随年龄增大,并有１－２个发育高峰;提示鼻部发育具有阶段性;２项指标的曲线随年龄增长变化较小。４项指标男女性的曲     

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)     

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.     

Oligonucleotide fingerprints of RNA species obtained from rhabdoviruses belonging to the vesicular stomatitis virus subgroup.

The relationships among the genomes of various rhabdoviruses belonging to the vesicular stomatitis virus subgroup were analyzed by an oligonucleotide fingerprinting technique. Of 10 vesicular stomatitis viruses, Indiana serotype (VSV Indiana), obtained from various sources, either no, few, or many differences were observed in the oligonucleotide fingerprints of the 42S RNA species extracted from standard B virions. Analyses of the oligonucleotides obtained from RNA extracted from three separate preparations of VSV Indiana defective T particles showed that their RNAs contain fewer oligonucleotides than the corresponding B particle RNA species. The fingerprints of RNA obtained from five VSV New Jersey serotype viruses were easily distinguished from those of the VSV Indiana isolates. Three of the VSV New Jersey RNA fingerprints were similar to each other but quite different from those of the other two viruses. The RNA fingerprints of two Chandipura virus isolates (one obtained from India and one from Nigeria) were also unique, whereas the fingerprint of Cocal virus RNA was unlike that of the serologically related VSV Indiana.     

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.     

Automated assay of phosphohydrolases by measuring the released phosphate without deproteinization.

We describe an automated determination of inorganic phosphate in the presence of proteins and its application for the assay of NaK-ATPase (EC 3.6.1.3) and other insoluble phosphohydrolases. After incubation the enzyme reaction is stopped at neutral pH with 3.3% (w/v) sodium dodecyl sulfate plus 30 mm EDTA (final concentration). The released phosphate is measured on the Technicon Autoanalyzer as phosphomolybdate reduced with ferrous ammonium sulfate and thiourea to molybdenum blue. EDTA enhances color development and solubilization of the proteins. The reagents are stable at room temperature and are formulated from cheap, common chemicals.