On the oscillatory phenomenon in an oil/water interface

A simple theoretical model is presented for simulating the self-sustained oscillations of electric potential and pH at an oil/water interface appearing in a two-phase system composed of 2-nitropropane solution containing picrate acid and an aqueous solution of cetyltrimethylammonium bromide. In the present model, a well-known condition necessary for the occurrence of self-sustained oscillations, i.e., the presence of a positive feedback process far from equilibrium, is taken into account in a set of kinetic equations to describe simplified characters of the following two processes: (i) a cooperative formation of ion pair complexes at the interface, and (ii) supply of picrate anions and cetyltrimethylammonium cations to the interface accompanied by release of ion pair complexes to the organic phase. The numerical solutions of the present equations are shown to reproduce fairly well the characteristic properties of the oscillation of electric potential and pH such as wave forms and frequencies.     

Dynamic light scattering study of suspensions of purple membrane

Purple membrane from Halobacterium halobium in suspensions has been studied by quasielastic light scattering. The intensity correlation functions of polarized scattered light were measured at various K2 values (K being the magnitude of the scattering vector), and the first cumulant Gamma of the field correlation function G1(tau) was obtained by a cumulant expansion method. The apparent diffusion coefficient Gamma /K2 did not increase monotonically with K2 values and showed a distinct anomaly in an intermediate range of K. A theoretical formulation of G1(tau) for a disc and an extremely oblate ellipsoidal shell of revolution (S. Fujime and K. Kubota, Biophys. Chem. 23 (1985) 1) was applied to the analysis of the spectra, and characteristic features of experimental spectra were well reproduced. It was suggested that a strong interference effect between scattered rays on Gamma /K2 should be attributed to a slight noncircular shape of the purple membrane and that a contribution to Gamma /K2 from membrane flexibility should be taken into account. This study will provide experimental evidence of the feasibility of membrane studies by dynamic light scattering.     

低温对不同耐寒力的黄瓜幼苗子叶的各细胞器中NAD~+-苹果酸脱氢酶的影响

NAD~+-MDH在黄瓜子叶中的定位是细胞溶质中占总活性的55～59％,线粒体为38～35％,叶绿体为7％。其同工酶谱亦为细胞溶质中带数最多,全青为5条,粤早3号为4条,线粒体和叶绿体均为1条,品种间无明显差异。黄瓜幼苗随低温胁迫的加剧,伤害逐步加重,子叶电解质渗出率明显增加,NAD~+-MDH活性亦不断下降,其中叶绿体的NAD~+-MDH对低温最敏感,1±1℃处理就能反映品种间耐寒力的差异。叶绿体和线粒体的NAD~+-MDH同工酶对低温的反应与活性变化一致,谱带数没有差异,只是活性降低。细胞溶质部分酶带较多,各条酶带对低温的反应不同。     

用免疫粘附凝集试验区分两种有肾综合征出血热病原体

<正>有肾综合征出血热(HFRS)的不同类型已为世界许多地区所报导。这些疾病均以发烧、出血和肾的机能损伤为特征,但疾病的症状和流行病学的表观是不同的。以间接免疫荧光抗体(IFA)试验结果指出,朝鲜出血热和流行性肾病以及日本、中国的流行性出血热之间有血清学关系。近年来,亦提示了朝鲜出血热和流行性肾病的抗原之间的区别。     

The Molecular Basis of Genetic Diversity among Cytoplasms of Triticum and Aegilops. III. Chloroplast Genomes of the M and Modified M Genome-Carrying Species

The restriction fragment patterns of chloroplast DNAs of all M or modified M genome-carrying Aegilops species, and those of common wheat (Triticum aestivum), Ae. umbellulata and Ae. squarrosa as referants, have been analyzed using eight restriction endonucleases, BamHI, EcoRI, HindIII, KpnI, PstI, SalI, SmaI and XhoI. Nine distinctly different chloroplast genomes are evident, and the mutual relatedness among them is estimated based on the number of different restriction fragments. The results lead to the following conclusions. (1) Chloroplast genomes of three Comopyrum species, Ae. comosa, Ae. heldreichii and Ae. uniaristata, are more closely related with each other and are greatly different from those of the Amblyopyrum species, Ae. mutica, and of Ae. umbellulata and Ae. squarrosa. (2) Ae. crassa's chloroplast genome lies at the center of chloroplast genome diversification, whereas those of common wheat, Ae. squarrosa and Ae. uniaristata are three extreme forms lying far from the center. (3) Chloroplast genomes of three 4x species, Ae. biuncialis, Ae. columnaris and Ae. triaristata, arose from Ae. umbellulata, and that of a fourth 4x species, Ae. ventricosa , arose from Ae. squarrosa. The chloroplast origins of two other 4x species, Ae. ovata and Ae. crassa, remain unsolved. (4) The chloroplast genomes of two Ae. mutica strains are identical, even though their cytoplasms exert quite different effects on male fertility, heading date and growth vigor of common wheat.     

Genetic Control of Meiosis in Rice, ORYZA SATIVA L. III. Effect of DS Genes on Genetic Recombination

The recombination frequency as influenced by five independent recessive ds genes was measured on three segments of different chromosomes of rice, Oryza sativa L. Each ds gene in the homozygous condition resulted in an almost equally reduced recombination frequency in the three segments. When the mean reduction in recombination frequency was related to the reduction of chiasma frequency, the five ds genes were divided into two types: in one type the reduction of chiasma frequency almost corresponded to the mean reduction of recombination frequency, and in the other the chiasma frequency was greatly reduced in comparison with the mean reduction of recombination frequency. Three of the five ds genes were found to belong to the former group. In both types, normal synaptonemal complexes were observed in pachytene cells homozygous for ds genes. This finding suggests that ds genes do not affect the formation of synaptonemal complexes which are regarded as the prerequisite structure for crossing over.     

Kinetics of formation of maltose and isomaltose through condensation of glucose by glucoamylase

A kinetic model was devised for the hydrolysis and synthesis of maltose and isomaltose by two glucoamylases from Rhizopus niveus and Aspergillus niger, and the validity of the model was verified experimentally at 313 K and pH 5.0. For both enzymes, the formations of maltose and isomaltose from glucose were parallel reversible reactions, and glucosyl transfer between maltose and isomaltose was not observed. The enzymes catalyzed rapid hydrolysis and synthesis of maltose. Isomaltose was hydrolyzed and synthesized more slowly, but the level produced from glucose was much higher than that of maltose. These hydrolysis and condensation reactions were expressed well by the model.     

Invertase immobilization via its carbohydrate moiety

After periodate oxidation of its glycosidic component, invertase was covalently bound onto three types of modified solid supports: glycidyl methacrylate, styrene-divinylbenzene copolymers, and bead cellulose. Direct reaction of the invertase aldehyde groups that were formed with amino groups of the support and use of the modified Ugi reaction have been employed as immobilization procedures. Apart from binding methods, the important effects of the buffer, support, conditions of periodate oxidation, and the length of the spacer on the activity of the enzyme conjugate have been investigated. Superior conjugate activity was obtained, via modified Ugi reaction, by the immobilization of a suitably oxidized invertase to a styrene-divinylbenzene copolymer having free amino groups.