小鼠肝脏免疫抑制蛋白质(LISP)的分离纯化和鉴定

用硫酸铵分段盐析及DEAE-Sephadex A-50、羟磷灰石和CM纤维素等多种柱层析方法,从正常小鼠肝浸液中分离纯化出一种免疫抑制蛋白质(LISP)。在体外用微量该蛋白质就能强烈抑制小鼠T、B淋巴细胞对促有丝分裂原和同种异型抗原的增生反应。纯化的蛋白质在聚丙烯酰胺凝胶电泳(PACE)和等电聚焦(IEF)鉴定时均显示为一条区带,其等电点(pI)值在7.5—7.8范围。沉降系数利S_(20),w为5.39。Sephadex G-100凝胶层析测得LISP的分子量为78,000道尔顿。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)提示LISP是由二个相同的亚基组成,亚基分子量为38,500道尔顿。LISP是一种既非糖蛋白又非脂蛋白的碱性蛋白质,对它的氨基酸组成也作了分析。     

Ovarian and fat body protein concentrations in Ips sexdentatus (Coleoptera: Scolytidae) parasitized by nematodes

The protein concentrations of fat body and ovaries in Ips sexdentatus either uninfected or infected by Parasitaphelenchus sp., P. sexdentati, or Contortylenchus diplogaster were measured at various stages of insect development, from preswarming maturation to the first oviposition (24 hr after mating). Weight variations of the fat body and ovaries in insects infected by C. diplogaster show the same evolution as those observed in uninfected insects, but at a much lower level. Fat body proteins in uninfected insects reach their minimum level during swarming, but they remain fairly constant throughout the maturation of the first egg. After dropping shortly after swarming, the ovarian protein level in such insects increases in two stages during ovarian maturation. The first stage, which corresponds to a slow protein incorporation, takes place during the first 12 hr after mating. During the second stage, i.e., beyond 12 hr, a significant level of proteins is rapidly incorporated into the ovaries. In insects infected by Parasitaphelenchus fat body proteins are reduced and protein incorporation into the ovaries is reduced; Parasitaphelenchus would thus affect at least some proteins required for ovarian maturation in their host. Fat body protein levels are even more affected by C. diplogaster than by Parasitaphelenchus, while incorporation into ovaries seems to be less affected in spite of slower ovarian growth. C. diplogaster might thus essentially act both upon proteins which are not required for the ovarian maturation of their host and upon nonproteinaceous substances that are required for such maturation. Results are discussed in relation to the possible mode of action of parasitic nematodes.     

细菌(Pseudomonas maltophilia)之绒毛膜促性腺激素(hCG)结合物质之研究

 细菌(Pseudomonas moltophilia)与hCG及LH有特异的亲和力,实验发现,细菌之生长曲线与hCG结合活性成平行关系,96小时达高峰,细菌之培养液中含有可溶性结合蛋白,该蛋白经硫酸铵沉淀(80％饱和度)、Sephadex G-100柱层析、DEAE-纤维素柱0.5mol/L NaCl梯度洗脱,再过Sepharose CL-AB柱,收集之活性部分经SDS电泳测得其分子量为70,000,凝胶层析测Stokes radius为41A,Schiff氏染色未见着色带。     

Dietary selenium status and plasma thyroid hormones in chicks

Experiments were conducted to study the effect of marginal levels of selenium and vitamin E on plasma thyroid hormones of meattype chicks. Plasma thyroxine (T₄) was significantly increased when a semipurified diet was supplemented with either selenium or vitamin E. Triiodothyronine (T₃) was also significantly increased by vitamin E and in one experiment with selenium supplementation. No significant increase in these hormones was observed in birds fed a corn-soybean-meal diet supplemented with these nutrients. Plasma corticosterone level was reduced and weight of the bursa of Fabricius increased by selenium or vitamin E supplementation. These nutrients may be necessary for providing the optimum thyroid conditions for activity of thyroid peroxidase.     

Cytochromec oxidase fromParacoccus denitrificans in Triton X-100: Aggregation state and kinetics

Cytochromec oxidase fromParacoccus denitrificans was homogenously dispersed in Triton X-100. Using gel exclusion chromatography and sucrose gradient centrifugation analysis a molecular weight of the detergent-protein complex of 155,000 was determined. After subtraction of the bound detergent (111 mol/mol hemeaa ₃) a molecular weight of 85,000 resulted, which agreed well with the model of a monomer containing two subunits. This monomer showed high cytochromec oxidase activity when measured spectrophotometrically in the presence of Triton X-100 (V _max=85 s^–1). The molecular activity, plotted according to Eadie-Hofstee, was monophasic as a function of the cytochromec concentration. AK _m of 3.6×10^–6 M was evaluated, similar to theK _m observed in the presence of dodecyl maltoside [Naeczet al. (1985).Biochim. Biophys. Acta 808, 259–272].     

Target size analysis by radiation inactivation: a large capacity tube rack for irradiation in a Gammacell 220

Target size analysis by radiation inactivation is now a well-established method to study structure-function relationships in biologically active macromolecules without prior purification or even solubilization. Recently, it was reported that a relatively low-dose-rate but commonly available gamma source such as the Gammacell 220 (Atomic Energy of Canada, Ltd.) can be used to carry out radiation inactivation experiments providing it is appropriately calibrated with enzymes of known radiation sensitivities (G. Beauregard and M. Potier (1982) Anal. Biochem. 122, 379-384). In this report, a tube rack designed to fit into the irradiation chamber of the Gammacell 220 which allows five experiments (at 30 tubes per experiment) to be carried out simultaneously with both standard and unknown samples is described. The dose rates delivered at different positions in the rack were determined by irradiating rat liver cytosolic neuraminidase, an enzyme of known radiation sensitivity. A better than 2.7% agreement was obtained between experimental dose rate and computed values from isodose curves previously published by other authors (O. A. Curzio and H. O. Quaranta (1982) Int. J. Appl. Radiat. Isot. 33, 1-3).     

Effects of non-24-hour days on reproductive efficacy and embryonic development in mice

ICR female mice were exposed to either 22 (L11, D11) or 26 hour day (L13, D13) light/dark cycles for at least 2 weeks before mating and/or during pregnancy. The mating rates of these animals decreased considerably. When pregnant females were examined at gestation days 12.0 or 17.5, resorption rates were increased, the embryos weighed less, and development was retarded in the experimental groups with preconceptional exposure to non-24-hour days. We speculate that in mice maternal and paternal pre- and periconceptional environment of daily light/dark cycles is important for normal reproductive efficacy and normal embryonic development during pregnancy.     

The effect of whey protein hydrolyzates on the lactic acid fermentation

Summary The batch fermentation of whey permeate to lactic acid was improved markedly by the addition of enzymehydrolyzed whey protein. Acid concentrations greater than 90 g/l were achieved at a productivity of 4.3 g/l per h and a 98% substrate use. Cell mass concentration reached 6 g/l. The acid productivity achieved is somewhat higher than that typical for fermentation of whole whey. The process economics, based on in-house hydrolyzate preparation, look promising. Presented in this paper are the experimental results showing the effects of hydrolyzate concentration on acid and cell mass production.     

Using otolith weight to age fish

The problem of determining and verifying ages of fish, from populations having a considerable variation in size at age, has been investigated using the relationship between otolith size and fish size, which has been shown by several authors to be influenced by growth rate. In such a population of Sardinella aurita Val. an index of age can be obtained for individual fish by calculating the equivalent otolith weight at a particular fish length, using the otolith weight–fish length relationship determined for each age group. This statistic not only permits a much greater proportion of fish to be assigned ages than is possible with otolith reading alone, but also enables the age groups to be verified as year classes. However, it is concluded that, although appropriate models based on otolith-fish size relationships can predict age for groups of fish in which growth rates are known or can be assumed to be consistent, such techniques have a limited application in ageing fish from wild populations with highly variable growth rates.     

下肢长骨骨重的非对称性

本文测量82副中国成年下股长骨即股骨,胫骨和腓骨的重量,在两侧骨重相差>1％时,则股骨、胫骨和腓骨及其三骨总重均以非对称性为多,均具有非常显著性差异(P<0.001)。除腓骨重具有明显侧别差异外,其余无显著性侧别差异,对腓骨侧差解释为:①腓骨主要机能是肌的附着,而下肢对踢和足趾取物具有明显的侧别差异;②以两侧骨重相差>1％时为非对称性的标准,由于腓骨绝对重量较小,在两侧相差<0.5克时即多属非对称性。