慢性蜜蜂麻痹病病毒核酸与蛋白质组分的研究

从自然感染的意大利麻痹病蜂(APis mellifera)头部,经二次差速离心与蔗糖梯度离心获得纯化的慢性蜜蜂麻痹病病毒(CBPV)。纯化的CBPV制备物感染正常蜜蜂,4天后出现典型的麻痹症状,接着死亡,平均死亡率分别为95％与100％。SDS-聚丙烯酰胺凝胶电泳分析,二次差速离心初步纯化的病毒制备物含有多条蛋白带,而蔗糖密度梯度纯化的病毒制备物仅含有单一的多肽带。5％、7.5％与10％SDS-聚丙烯酰胺凝胶电泳分析,均检测出一种病毒蛋白质,分子量大约为24,200道尔顿,而且不同凝胶浓度检测的蛋白质分子量相近。慢性蜜蜂麻痹病病毒核酸也用SDS-聚丙烯酰胺凝胶电泳分析,结果表明,凝胶中有5条带,对核酸酶敏感,证明该病毒含有5个单股RNA组分。对慢性蜜蜂麻痹病病毒的基因组结构进行了讨论。     

Evolution of the lipoprotein gene in the enterobacteriaceae. Cloning and DNA sequence of the lpp gene from Proteus mirabilis

We cloned the lipoprotein gene from Proteus mirabilis and determined its DNA sequence. Comparison with the lpp genes from Escherichia coli, Serratia marcescens, Erwinia amylovora and Morganella morganii revealed several unique features of the evolution of the lpp gene in the Enterobacteriaceae and enabled us to establish phylogenetic relationships between these bacteria.     

Radiation chemistry of an aqueous solution of glycine: compounds of interest to chemical evolution studies

Summary We have examined the radiolysis of an O₂-free aqueous solution of glycine at absorbed doses of⁶⁰Co gamma-radiation of up to 20 Mrad. At least 20 compounds are formed during radiolysis, among them several amino acids, an oligoamine, and the nitrogen-free polymers (M_w28,000 daltons). When dicyandiamide is present in the solution of glycine, various nitrogen-containing products, including some polymers (M_w12,000 daltons), are synthesized along with radiolytic products of glycine; polyglycines are not formed. We have determined the radiation-chemical yields of radiolytic-product formation and of decomposition of glycine, and have considered possible free-radical reactions leading to the radiation-induced changes observed.     

Mutation induction in Escherichia coli incubated in the reaction mixture of NADPH-dependent lipid peroxidation of rat-liver microsomes

Experiments were carried out to examine mutation induction in E. coli cells incubated in the reaction mixture of NADPH-dependent lipid peroxidation of microsomes isolated from rat liver. The results obtained were as follows: (1) Lipid peroxidation of microsomes occurred extensively on incubation with NADPH and Fe2+. In the E. coli WP2uvrA(pKM101) system, the mutation frequency to streptomycin resistance increased markedly when the cells were incubated in the reaction mixture of microsomal lipid peroxidation. The induced mutation frequencies were dependent on the extent of the lipid peroxidation. (2) It was also found that the mutations were induced at the same rate as in the case of (1) when the cells were added to the microsomal suspensions after the reactions due to the short-lived free radicals had terminated. (3) The cytotoxicity of the lipid peroxidation products was larger in the DNA repair-defective mutant, E. coli SR18 (uvrArecA) than the wild-type strain, SR749. From these results it is concluded that some DNA-damaging and mutagenic substances are indeed produced in the degradation process of peroxidized polyunsaturated fatty acids in liver microsomal lipids.     

Stimulation of some litter-decomposing basidiomycetes by shikimic acid

Shikimic acid, which constitutes 1.5-2.5% of the dry matter in needles of Scots pine, was found to stimulate the growth of various litter-decomposing basidiomycetes of the genera Marasmius, Mycena and Xeromphalina in a synthetic nutrient medium. Out of eighteen litter-decomposing species, ten were stimulated by shikimic acid, wheras the eight mycorrhizal and four wood-rotting species tested were not affected. Maximal effect was obtained at a concentration of ca 2 m M . Growth experiments at varying pH-values indicated active uptake of shikimic acid. Even in the presence of aromatic amino acids, shikimic acid stimulated the growth of the fungi. In certain species the strong inhibiting effect of phenylalanine, tyrosine and tryptophan, when added simultaneously, was reversed in the presence of shikimic acid. Fungi which were stimulated by shikimic acid were also able to use this compound as their sole carbon source. Maximal stimulating effect of shikimic acid occurred when glucose had been added at optimal concentration.     

Application of fast atom bombardment mass spectrometry to chlorogenic acids

The technique of positive- and negative-ion fast atom bombardment mass spectrometry has been shown to be capable of producing molecular mass and useful fragmentation information for the structural elucidation of chlorogenic acids. The mass spectra of chlorogenic acid and the related compounds 3′-O-methylchlorogenic acid, neochlorogenic acid, 4,5-dicaffeoyl quinic acid and 1,5-dicaffeoyl quinic acid are compared with those obtained by electron impact mass spectrometry.     

The present situation and problems of mariculture in Japan

Summary Recently, rearing techniques for various kinds of fish have advanced markedly, and the number of fish species in commercial production increases every year. The establishment of methods for stable, reproducible mass culture of live foods that are highly nutritious is still necessary to improve the survival and growth rates of larval fish. Since, however, the mass propagation of live foods requires costly equipment and depends upon weather conditions, the development of artificial larval diets to replace live foods will be essential. In mariculture local trash fish are commonly used as a feed for juvenile fish because of their low cost and high acceptability to the cultured fish. However, this frequently results in deterioration of water environments, leading to the appearance of fish diseases and pollution. The development of artificial diets such as moist pellets will also improve these conditions.Mass-cultured fish seed are mainly used for the culture of commercial-sized fish, even though they are generally poorer in taste than wild fish. They are also used for release into coastal waters to promote inshore fishery, but it is difficult to evaluate the effect of stocking on the total catch. Another type of mariculture depends upon raising wild juveniles, though there are clearly too few caught to supply enough fish seed to satisfy the ever-growing demands of fish breeders. Thus, the cultivation of broodstock to produce high-quality eggs is important.     

Uptake of free amino acids by the diatom,Melosira mediocris

Individual ¹⁴C-labelled amino acids are rapidly removed from dilute solution in artificial sea water (0.2 mol 1^–1) by suspensions of Meliosira medocris. The rate of disappearance of radioactivity corresponds closely to removal of primary amines as determined by measurement of the rate of decrease of fluorescamine-positive material. Net removal of naturally occurring free amino acids from the sea water habitat from which the alga was isolated is demonstrated using high performance liquid chromatography. Removal of amino acids from natural sources makes a significant contribution to the carbon requirements of the alga as well as supplying significant amounts of amino nitrogen.     

Concentration of Free Amino Acids in Primary Cultures of Neurones and Astrocytes

The cellular distribution of free amino acids was estimated in primary cultures (14 days in vitro) composed principally of cerebellar interneurones or cerebellar and forebrain astrocytes. In cultured neural cells, the overall concentration of amino acids resembled that found in brain at the corresponding age in vivo. In the two neural cell types, there were marked differences in the distribution of amino acids, in particular, those associated with the metabolic compartmentation of glutamate. In neuronal cell cultures, the concentrations of glutamate, aspartate, and gamma-aminobutyric acid were, respectively, about three, four, and seven times greater than in astrocytes. By contrast, the amount of glutamine was approximately 65% greater in astroglial cell cultures than in interneurone cultures. An unexpected finding was a very high concentration of glycine in astrocytes derived from 8-day-old cerebellum, but the concentrations of both serine and glycine were greater in nerve cell cultures than in forebrain astrocytes. The essential amino acids threonine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, and arginine were all present in the growth medium, and small cellular changes in the contents of some of these amino acids may relate to differences in their influx and efflux during culturing and washing procedures. The present results, together with our previous findings, provide further support for the model assigning the "small" compartment of glutamate to glial cells and the "large" compartment to neurones, and also underline the metabolic interaction between these two cell types in the brain.     

Postischemic Cerebral Lipid Peroxidation In Vitro: Modification by Dietary Vitamin E

Using an in vitro system, we studied the effect of postischemic reoxygenation on cerebral lipid peroxidation in relation to the dietary intake of vitamin E (VE) in rats. Homogenates prepared from VE-deficient, -normal, and -supplemented brains, which were previously rendered ischemic for 30 min by decapitation, were incubated under air or nitrogen gas for 60 min. The extent of peroxidation in brain tissue was estimated by a thiobarbituric acid (TBA) test and by diene conjugation in total lipid extracts. The brain levels of alpha-tocopherol and of total and free fatty acids (FAs) were also determined. Aerobic incubation increased TBA reactants in all dietary groups; the effect was largest in the VE-deficient group, intermediate in the VE-normal group, and smallest in the VE-supplemented group. In contrast, nitrogen incubation did not alter the basal levels of TBA reactants except for a small rise associated with VE deficiency. Conjugated dienes changed in parallel with TBA reactants. alpha-Tocopherol decreased after aerobic incubation and also, to a lesser degree, after nitrogen incubation in each dietary group. Only in the reoxygenated samples of the VE-deficient group was there a significant fall in total polyunsaturated FAs. The levels of free FAs continuously increased throughout ischemia and subsequent incubation. However, the level of free polyunsaturated FAs was similar after aerobic and nitrogen incubation in each dietary group, and was not affected by VE. Thus, cerebral reoxygenation after ischemia propagates peroxidative reactions within esterified polyunsaturated FAs. The modification by VE of reoxygenation-induced lipid peroxidation suggests free radical mediation.