The hypogonadotropic state of the prepubertal male rhesus monkey (Macaca mulatta) is not associated with a decrease in hypothalamic gonadotropin-releasing hormone content

Hypothalamic contents of gonadotropin-releasing hormone (GnRH) in neonatally orchidectomized infant, juvenile, and adult monkeys were measured by a radioimmunoassay (RIA) and by an in vivo bioassay that utilized luteinizing hormone (LH) secretion in estrogen- and progesterone-treated ovariectomized rats. The results of the bioassay provided no evidence to suggest that hypothalamic GnRH content in juvenile monkeys (mean = 83 ng/hypothalamus; n = 3) was less than that in infants (mean = 54 ng/hypothalamus; n = 4) and adults (mean = 36 ng/hypothalamus; n = 3). A similar developmental pattern in hypothalamic GnRH content was also observed when the decapeptide was measured by RIA. In striking contrast to the maintenance of hypothalamic GnRH content throughout postnatal development, pituitary gonadotropin contents and serum gonadotropin concentrations were markedly reduced in juvenile monkeys.     

Generic liposome reagent for immunoassays

We have derivatized liposomes with antibodies by using avidin to crosslink biotinylated phospholipid molecules in the liposome membranes with biotinylated antibody molecules. A comparison of the biotin binding activity of avidin in solution and avidin associated with liposomes shows that avidin bound to biotinylated phospholipid in liposome membranes retains full binding activity for additional biotin molecules. Changes in the fluorescence spectrum of avidin have been used to characterize the binding capacity of avidin for biotin in solution, and change in intensity of light scattered due to aggregation of liposomes was used to measure the biotin binding activity of avidin associated with liposomes. Relative amounts of the biotinylated phospholipid, avidin, and biotinylated antibody have been optimized to produce stable liposomes which are derivatized with up to 1.7 nmol of antibody/mumol of lipid. These derivatized liposomes are highly reactive to immunospecific aggregation in the presence of multivalent antigen. A linear increase in light scattering was recorded between 1 and 10 pmol of antigen. This work shows that liposomes containing biotinylated phospholipid can be a successful generic reagent for immunoassays.     

广西窄腹茧蜂属一新种：膜翅目：茧蜂科：茧蜂亚科

茧蜂亚科已知有123个属(Quicke,1987),其中窄腹茧蜂属Angustibracon Quicke是Quicke(1987)根据分布在印度的1个种Bracon leptogaster Cameron重新组合为1个新属而建立,迄今已定名种仅此1种。我们整理广西茧蜂标本时,鉴定出该属1新种。这是本属种类在我国分布的首次报道,现将该属属征和新种形态记述如下。新种模式标本存湖南农学院昆虫标本室。     

中国三节茧蜂属Acampsis Wesmale记述(膜翅目:茧蜂科:屏腹茧蜂亚科)

三节茧蜂属Acampsis Wesmael是屏腹茧蜂亚科中的1个小属,全世界仅知1种。本文新添在我国发现的2个新种:中华三节茧蜂A.chinensis sp.nov.(陕西)和湖南三节茧蜂A.hunanensis sp.nov.(湖南)。这是本属在我国的首次发现,也是在东洋区的首次报道。     

Failure to kindle seizures after repeated intracerebral administration of arginine vasopressin

In an attempt to kindle seizures with arginine-vasopressin (AVP), we injected AVP into the amygdala or hippocampus of rats. Although behavioral and electrographic alterations were sometimes observed, seizures failed to develop, even in rats that had previously been kindled with electrical stimulation. This and previous failures to kindle seizures by intraventricular injections of AVP call into question the possibility of AVP kindling.     

Models for age structured populations with distributed maturation rates

In the use of age structured population models for agricultural applications such as the modeling of crop-pest interactions it is often essential that the model take into account the distribution in maturation rates present in some or all of the populations. The traditional method for incorporating distributed maturation rates into crop and pest models has been the so-called distributed delay method. In this paper we review the application of the distributed delay formalism to the McKendrick equation of an age structured population. We discuss the mathematical properties of the system of ordinary differential equations arising out of the distributed delay formalism. We then discuss an alternative method involving modification of the Leslie matrix.     

Structural analysis of fibrinogen synthesized by cultured chicken hepatocytes in the presence or absence of dexamethasone

Hepatocyte monolayers, derived from chick embryos and cultured in chemically defined medium without hormones, synthesize and secrete fibrinogen that resembles chicken plasma fibrinogen immunochemically and structurally. Addition of a synthetic glucocorticoid, dexamethasone, to the cultured cells resulted in an appreciable and relatively selective increase in fibrinogen synthesis. Autoradiography of fibrinogen that had been metabolically labelled with [35S]methionine and then subjected to SDS-polyacrylamide gel electrophoresis, unreduced or under disulfide-reducing conditions, revealed that only dimeric forms of fibrinogen, containing undegraded A alpha, B beta, and gamma chains, were secreted under stimulated and unstimulated culture conditions.     

Transfer of polycyclic aromatic hydrocarbons between model membranes: relation to carcinogenicity

Polynuclear aromatic hydrocarbons (PAH), some of which are potent carcinogens, are common environmental pollutants. The transport processes for these hydrophobic compounds into cells and between intracellular membranes are diverse and are not well understood. A common mechanism of transport is by spontaneous desorption and transfer through the aqueous phase. From the partitioning parameters, we have inferred that the rate limiting step involves solvation of the transfer species in the interfacial water at the phospholipid surface. Transfer of 10 PAH (pyrene, 3,4-benzophenanthrene, triphenylene, chrysene, 1,2-benzanthracene, 1,1'-binaphthyl, 9-phenylanthracene, 2,2'-binaphthyl, m-tetraphenyl and 1,3,5-triphenylbenzene) out of phosphatidylcholine vesicles has been examined. Our results show that the molecular volume of the PAH is a rate-determining factor. Moreover, high performance liquid chromatography (HPLC) data confirms the hypothesis that the rate of transfer is correlated with the size of the molecule and with the partitioning of the molecule between a polar and hydrocarbon phase. The kinetics and characteristics of the spontaneous transfer of carcinogens are likely to have a major impact on the competitive processes of PAH metabolism within cells.     

蚕豆叶片发育与衰老过程中超氧物歧化酶活性与丙二醛含量变化

蚕豆植株叶片随茎节自上而下表现出明显的发育与衰老顺序,可作为衰老特征的是叶绿素和蛋白质含量明显下降。蚕豆叶中SOD活性主要定位于12 000× g离心后所得的上清液和叶绿体组分。衰老叶片的SOD总活性和叶绿体组分的相对活性都有所下降,SOD同工酶谱也发生了改变。O_2~ 产生速率随叶龄增大而稍上升;而MDA含量在叶片外观表现枯黄衰老征兆前就急剧上升。可能因为衰老叶片过氧化氢酶活性大幅度下降与SOD之间的不平衡,致使O_2~ 代谢中间产物累积而引起膜的损伤.     

毛木耳一新变种

本文报道了发现于河北省石家庄地区的木耳科(Auricualariaceae)、木耳属(Auricu-laria)毛木耳的一个白色变种。其色泽如银耳故命名银白木耳[A．Polytricha(Mont.)Sacc. Var．Argentca D．Z．Zhao et C．J．Waag var．Nov．]是经济价值高、可供进一步开发应用的食用菌新菌种。通过三代五次人工驯化培养,生物性状稳定,颜色纯白,朵大肉厚,外观美丽,并具有抗木霉、耐高温,生物效率高等特点。