三尖杉叶精油化学成分的研究

三尖杉叶精油化学成分的研究苏应娟,王艇,张宏达（中国科学院武汉植物研究所武汉４３００７４）（中山大学生命科学学院广州５１０２７５）关键词三尖杉,精油,化学分类ＡＳＴＵＤＹＯＮＣＨＥＭＩＣＡＬＣＯＮＳＴＩＴＵＥＮＴＳＯＦＥＳＳＥＮＴＩＡＬＯＩＬＦＲＯＭ...     

Detection of immunoglobulin heavy chain IgG3 polymorphism in wild mice with xenogeneic monoclonal antibodies

We have generated four xenogeneic rat antimouse IgG₃ monoclonal antibodies recognizing at least three different antigenic determinants (epitopes) on BALB/c IgG₃ molecules. These antibodies were used in solid-phase blocking radioimmunoassays for detection of the epitopes in sera of 40 inbred strains and 134 wild mice. These antibodies detect genetic polymorphism of IgG₃ isotype among wild mice even though there is no polymorphism found among 40 inbred strains tested (except X-chromosome-linked immunodeficient CBA/N strain which lacks IgG₃ molecules). An IgG₃ variant was also isolated from hybridomas derived from Mus spretus.Abbreviations Igh-C immunoglobulin heavy chain constant region - PVC polyvinyl chloride - RIA radioimmune assay - ELISA enzyme linked immunosorbent assay     

Human chromosomal assignments for 14 argininosuccinate synthetase pseudogenes: cloned DNAs as reagents for cytogenetic analysis

There are multiple, processed, dispersed pseudogenes for human argininosuccinate synthetase. Chinese hamster X human somatic cell hybrids were used to map DNA fragment groups corresponding to the single expressed gene and 14 pseudogene loci. Each chromosomal assignment was confirmed using hybrids containing very few human chromosomes and/or by demonstrating monosomic or trisomic dosage in human cell lines with chromosomal abnormalities. Pseudogenes were mapped to chromosomes 2cen-p25, 3q12-qter, 4q21-qter, 5 (two loci), 6, 7, 9p13-q11, 9q11-q22, 11q, 12, Xp22-pter, Xq22-q26, and Ycen-q11. DNA fragments from the expressed gene were mapped to 9q34-qter in agreement with the previous assignment for enzyme activity. A high-frequency restriction fragment length polymorphism mapped to 9q11-q22. The analyses emphasized the feasibility of using chromosomally abnormal human cell lines for confirmation and regionalization of gene-mapping assignments made using somatic-cell hybrids. Conversely, cloned DNA probes, once mapped and characterized, can be very valuable for determining the chromosomal composition of interspecies hybrids and the dosage of loci in human cells. The argininosuccinate synthetase cDNA is a convenient reagent for dosage analysis of 15 human loci on 11 different chromosomes. Improved reagents could be designed that would simplify Southern blot patterns by eliminating overlapping DNA fragments and providing a single DNA fragment for each locus.     

Combined effect of growth medium,age of cells and phase of sporulation on heat resistance and recovery of Hansenula anomala

Effects of two growth media, age of cells and phase of sporulation on heat resistance of Hansenula anomala were determined. Cells were grown on two solid media, McClary's acetate and V8 juice agars, at 21 ° C for 16 days. Heat resistance of cells was determined in 0.06 M potassium phosphate buffer at 48 ° C. Heat-stressed cells were plated on four recovery media: yeast extract-malt extract-peptone-glucose (YMPG), pH 7.0; YMPG, pH 3.5; YMPG containing 6% NaCl, pH 7.0; and YMPG containing 20% sucrose, pH 7.0. The composition of sporulation medium influenced the extent of sporulation and the relative heat resistance of sporulating cells. One-day-old cells were the most sensitive to heat. The heat resistance of cells was generally increased as the incubation time was extended to 16 days. Heat treatment caused a greater increase in sensitivity to NaCl than to sucrose or acid pH in recovery media. Young cells were more sensitive to NaCl than were older cells.     

Integument and sensory nerve differentiation ofDrosophila leg and wing imaginal discs in vitro

Summary An ultrastructural analysis is presented of the cuticular and neural structures formed by the prothoracic leg and wing imaginal discs of maleDrosophila melanogaster larvae during culture in vitro with 0.2 g/ml of -ecdysone. A pupal cuticle, and subsequently an imaginal cuticle with a well-defined epicuticle and a laminated endocuticle is formed. The ultrastructure of the epidermis and of cuticular structures such as bristles, trichomes, apodemes, and tracheoles is very similar to that found in situ. Dendrites and nerve cell bodies are formed in vitro, and sensory axons form nerve bundles similar to those of normal appendages in situ, despite their isolation from the central nervous system. It is concluded that at the ultrastructural level, differentiation in vitro closely parallels the normal course of development.     

Morphological changes in strains of Aspergillus flavus link ex fries and Aspergillus parasiticus speare related with aflatoxin production

Two strains ofAspergillus flavus Linkex Fr. and two strains ofA. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 247) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.)The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied,A. flavus NRRL 3251, lost completly the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations.A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.     

土牛膝碱（abidenine）的分离及结构测定

从土牛膝(Achyraanthes bidentata Bl.)的根中分离到一种新的生物碱——土牛膝碱(ubidenine),通过波谱方法测定出土牛膝碱的化学结构为5,6—二氢化—2,3,10,11—四甲氧基—二苯并[a,g]—喹嗪盐(1)。     

Induction of hepatic mitochondrial glycerophosphate dehydrogenase in rats by dehydroepiandrosterone.

Feeding the thermogenic steroid, 5-androsten-3 beta-ol-17-one (dehydroepiandrosterone, DHEA) in the diet of rats induced the synthesis of liver mitochondrial sn-glycerol 3-phosphate dehydrogenase to levels three to five times that of control rats within 7 days. The previously reported enhancement of liver cytosolic malic enzyme was confirmed. The induction of both enzymes was detectable at 0.01% DHEA in the diet, reached plateau stimulation at 0.1 to 0.2%, and was completely blocked by simultaneous treatment with actinomycin D. Feeding DHEA caused smaller, but statistically significant increases of liver cytosolic lactate, sn-glycerol 3-phosphate, and isocitrate (NADP(+)-linked) dehydrogenases but not of malate or glucose 6-phosphate dehydrogenases. The capability of DHEA to enhance mitochondrial glycerophosphate dehydrogenase and malic enzyme was influenced by the thyroid status of the rats; was smallest in thyroidectomized rats and highest in rats treated with triiodothyronine. 5-Androsten-3 beta,17 beta-diol and 5-androsten-3 beta-ol-7,17-dione were as effective as DHEA in enhancing the liver mitochondrial glycerophosphate dehydrogenase and malic enzyme. Administering compounds that induce the formation of cytochrome P450 enzymes enhanced liver malic enzyme activity but not that of mitochondrial glycerophosphate dehydrogenase. Arochlor 1254 and 3-methylcholanthrene also increased the response of malic enzyme to DHEA feeding.     

Refined crystal structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin

"Aged" organophosphoryl conjugates of serine hydrolases differ from the corresponding "non-aged" conjugates in their striking resistance to nucleophilic reactivation. The refined X-ray structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin were compared in order to understand the molecular basis for this resistance of "aged" conjugates. "Aged" and "non-aged" crystalline organophosphoryl-gamma-chymotrypsin conjugates were obtained by prolonged soaking of native gamma-chymotrypsin crystals with appropriate organophosphates. Thus, a representative "non-aged" conjugate, diethylphosphoryl-gamma-chymotrypsin, was obtained by soaking native crystals with paraoxon (diethyl-p-nitrophenyl phosphate), and a closely related "aged" conjugate, monoisopropyl-gamma-chymotrypsin, was obtained by soaking with diisopropylphosphorofluoridate. In both crystalline conjugates, the refined structures clearly reveal a high occupancy of the active site by the appropriate organophosphoryl moiety within covalent bonding distance of Ser195 O gamma. Whereas in the "non-aged" conjugate both ethyl groups can be visualized clearly, in the putative "aged" conjugate, as expected, only one isopropyl group is present. There is virtually no difference between the "aged" and "non-aged" conjugates either with respect to the conformation of the polypeptide backbone as a whole or with respect to the positioning of the side-chains within the active site. In the "aged" conjugate, however, close proximity (2.6 A) of the negatively charged phosphate oxygen atom of the dealkylated organophosphoryl group to His57 N epsilon 2 indicates the presence of a salt bridge between these two moieties. In contrast, in the "non-aged" conjugate the DEP moiety retains its two alkyl groups; thus, lacking a negative oxygen atom, it does not enter into such a charge-charge interaction and its nearest oxygen atom is 3.6 A away from His57 N epsilon 2. It is suggested that steric constraints imposed by the salt bridge in the "aged" conjugate lie at the basis of its resistance to reactivation.     

Group sequential distribution-free methods for the analysis of multivariate observations.

Many studies involve the collection of multivariate observations, such as repeated measures, on two groups of subjects who are recruited over time, i.e., with staggered entry of subjects. Various marginal distribution-free multivariate methods have been proposed for the analyses of such multivariate observations where some measures may be missing at random. Using the multivariate U statistic of Wei and Johnson (1985, Biometrika 72, 359-364), we describe the group sequential analysis of such a study where the multivariate observations are observed sequentially--both within and among subjects. We describe a multivariate generalization of the Hodges and Lehmann (1963, Annals of Mathematical Statistics 34, 598-611) estimator of a location shift that can be obtained via the multivariate U statistic with the Mann-Whitney-Wilcoxon kernel. We then describe large-sample group sequential interval estimators and tests based on an aggregate estimate of the location shift combined over all of the repeated measures. We also describe how the same steps could be employed to perform a group sequential analysis based on any one of the variety of marginal multivariate methods that have been proposed. These methods are applied to a real-life example.