Renin-like effects of NGF evaluated using renin-angiotensin antagonists

Intracranial injection of angiotensin II (AII) or activation of the cerebral isorenin-angiotensin system with intracranial renin causes an immediate thirst and a delayed sodium appetite in the rat. Nerve growth factor (NGF), a polypeptide trophic factor for peripheral sympathetic and sensory neurones, has also been reported to be a potent stimulus to thirst and sodium appetite when injected into the brain of the rat. Lewis et al. drew attention to the marked similarity between the effects of 2.5S NGF and renin on thirst and sodium appetite and suggested that the NGF responses were mediated by the cerebral isorenin-angiotensin system. We report here that NGF-induced thirst and sodium appetite, as well as increased blood pressure and increase ornithine decarboxylase activity in the brain and liver, depend on the formation of AII (see also ref. 6).     

安徽黄精和琅琊黄精核型初步研究

本文对黄精属（Ｐｏｌｙｇｏｎａｔｕｍ Ｍｉｌｌ．）中安徽特有２种植物的核型进行了初步研究，并分别人近缘种的核型进行了比较。结果表明：安徽黄精（Ｐ．ａｎｈｕｉｅｎｓｅ）核型公式为２ｎ＝２４＝４ｍ＋６ｓｍ＋１２ｓｔ＝２Ｔ，属３Ｂ核型，染色体相对长度组成为２ｎ＝２４＝６Ｌ＋６Ｍ２＋６Ｍ１＋６Ｓ．琅琊黄精（Ｐ．ｌａｎｇｙａｅｎｓｅ）核型公式为２ｎ＝１８＝１０ｍ＋２ｓｍ＋６ｓｔ，属２Ｂ核型；染色体相对长度组     

Plant genetics: increased outcrossing in hothead mutants

Arising from: S. J. Lolle, J. L. Victor, J. M. Young & R. E. Pruitt 434, 505-509 (2005); Lolle et al. reply. Lolle et al. report that loss-of-function alleles of the HOTHEAD (HTH) gene in Arabidopsis thaliana are genetically unstable, giving rise to wild-type revertants. On the basis of the reversion of many other genetic markers in hth plants, they suggested a model in which a cache of extragenomic information could cause genes to revert to the genotype of previous generations. In our attempts to reproduce this phenomenon, we discovered that hth mutants show a marked tendency to outcross (unlike wild-type A. thaliana, which is almost exclusively self-fertilizing). Moreover, when hth plants are grown in isolation, their genetic inheritance is completely stable. These results may provide an alternative explanation for the genome wide non-mendelian inheritance reported by Lolle et al.     

Structural polymorphism of I-E subregion antigens determined by a gene in the H-2K to I-B genetic interval

THE generation of immune responses in mice is influenced by Ir genes located in the I region of the major histocompatibility complex (MHC)(1). In some instances maximum responses require complementation by two genes, one in the I-A or I-B and the other in the I-E or I-C subregion(2,3). The effects of these genes are thought to be mediated by Ia alloantigens, which are cell surface molecules whose expression is controlled by the I region(4). This is based on the observations that anti-Ia sera inhibit in vitro immune responses(5,6), and soluble factors that enhance in vitro immune responses express Ia alloantigenic determinants(7,9). Jones et al.(10), using two-dimensional gel electrophoresis, observed that the expression of I-E subregion antigens is controlled by two genes, one in the I-A subregion, the other in the I-E subregion, and that the polymorphism of these antigens is influenced by an I-A subregion gene. As an explanation, the authors proposed that only one of the two polypeptide chains present in I-E immunoprecipitates is an I-E subregion product, the second being a product of the I-A subregion. Antisera obtained by cross-immunisation of I-E subregion-disparate strains of mice immunoprecipitates a molecular complex consisting of two chains, designated alpha and beta, with molecular weights of 32,000 and 29,000 respectively(11-14). Previous studies suggested that I-E antigens isolated from B10.A(5R) and B10.D2 mice had identical alpha-chains but different (beta)-chains(15). However, as these mice differed at multiple genetic regions, it was not possible to show which I subregion(s) determined the polymorphism of the E(beta) chain. Therefore, we investigated the effects of the I-A subregion on the polymorphism of I-E subregion antigens. We have now shown by peptide mapping that the I-E subregion polymorphism which Jones et al. found to be controlled by the I-A subregion probably reflects structural polymorphism of beta-chains controlled by an I-A subregion gene.     

玉簪属花药结构和花粉发育

利用石蜡切片技术研究了玉簪属植物花药结构和花粉发育,其观察结果表明：玉簪成熟花药由表层、药室内壁、中层和绒毡层等4层细胞组成;4个小孢子囊呈线形排列,并着生于药隔的向心面;小孢子母细胞分裂属连续型;成熟花粉为3-细胞结构,营养细胞充满大量淀粉粒;花药发育存在严重败育现象,花粉个体发育也具明显的不同步性;横切面观,玉簪花被片具有9～13个痕迹;2n=2x=60.从上述资料看,作者支持把“玉簪属”植物提升到“玉簪科”的水平.     

Dependence of Z-DNA antibody binding to polytene chromosomes on acid fixation and DNA torsional strain

There is considerable interest in the existence and significance of alternative conformations of DNA to the right-handed B-form described originally by Watson and Crick. The indirect immunofluorescence observations of Nordheim et al., Arndt-Jovin et al. and Lemeunier et al. that antibodies against left-handed Z-DNA bind to polytene chromosomes have thus assumed considerable importance. However, there is a paradox: some workers observe Z-DNA in interbands and others in bands. We report here that binding of Z-DNA antibodies to Drosophila polytene chromosomes prepared without acid fixation is at background level, and that following acid fixation the same antibody treatment leads to intense fluorescence. Depending on the extent of exposure to 45% acetic acid, fluorescence can occur primarily in interbands or in bands. Furthermore, antibody binding is dependent on elastic torsional strain in the DNA molecules.     

Specific inhibition of herpesvirus ribonucleotide reductase by a nonapeptide derived from the carboxy terminus of subunit 2

Ribonucleotide reductase, an essential enzyme for the synthesis of deoxyribonucleotides, is formed by the association of two nonidentical subunits in almost all prokaryotic and eukaryotic cells. The same model probably holds for the herpes simplex virus (HSV)-encoded ribonucleotide reductase; two polypeptides of relative molecular mass 136,000 (136K; H1) and 40K (H2) (referred to elsewhere as RR1 and RR2; see for example, Dutia et al.) have been associated with the viral enzyme by both genetic and immunological studies. Furthermore, DNA sequence analyses have shown significant stretches of amino-acid homology between these viral polypeptides and those of, respectively, subunit 1 (ref. 12) and subunit 2 (ref. 13) of the Escherichia coli and mammalian enzymes. To assess the involvement of the 40K polypeptide in reductase activity, we synthesized a nonapeptide corresponding to the sequence of its carboxy terminus with the intention of raising neutralizing antibodies specific for the viral activity (E.A.C. et al., in preparation). We report here the unexpected finding that the nonapeptide itself specifically inhibits the HSV ribonucleotide reductase activity in a reversible, non-competitive manner, and we suggest that it does this by impairment of the correct association of the two subunits. This phenomenon emphasizes the potential usefulness of synthetic peptides in probing critical sites involved in macromolecular interactions.     

Inclusive fitness theory and eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.     

Do human platelets have opiate receptors?

In their study of prostaglandin E1 (PGE1)-sensitive adenylate cyclase (AC) in rat brain homogenates, Collier and Roy claimed that the activity of this enzyme is inhibited by opiates. They also proposed that opiates exert their analgesic and allied effects by inhibiting AC of neurones that are normally stimulated by E prostaglandins. Studies using neuroblastoma x glioma hybrid cells supported this hypothesis. However, subsequent studies with mammalian brain and rat brain tissue slices yielded conflicting results. PGE1 also inhibits platelet aggregation, probably through activation of platelet AC. Gryglewski et al. showed that morphine inhibits the anti-aggregating effect of PGE1 on ADP- and adrenaline-induced platelet aggregation, and suggested that the inhibition by morphine is mediated through platelet AC activity. We report here our attempts to reproduce the results of Gryglewski et al. and our examination of the effect of morphine on PGE1-sensitive AC activity in platelet lysates and on PGE1-induced accumulation of cyclic AMP in intact platelets. The possible existence of opiate receptors in platelets was also assessed by direct binding studies with 3H-etorphine. In contrast to Gryglewski et al., we could not detect any effect of opiates on the aggregation of human platelets, nor did we find any other evidence supporting the presence of opiate receptors in these cells. Thus we conclude that the presence of opiate receptors in human platelets is unlikely.     

In defence of inclusive fitness theory

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Arguably the defining characteristic of the scientific process is its capacity for self-criticism and correction. Nowak et al. challenge proposed connections between relatedness and the evolution of eusociality, suggest instead that defensible nests and "spring-loaded" traits are key, and present alternative modelling approaches. They then dismiss the utility of Hamilton's insight that relatedness has a profound evolutionary effect, formalized in his widely accepted inclusive fitness theory as Hamilton's rule ("Rise and fall of inclusive fitness theory"). However, we believe that Nowak et al. fail to make their case for logical, theoretical and empirical reasons.     

一个新的Hamiltonian振幅方程的周期波解

由扩展的F-展开法获得了一个新的Hamiltonian振幅方程的新形式的周期波解.在极限情形得到了由双曲函数和三角函数表示的解.作为特别情形,得到了非线性Schr(o)dinger方程的相应解.     

No evidence for preservation of somatostatin-containing neurons after intrastriatal injections of quinolinic acid

Intrastriatal injections of excitotoxic amino acids and their analogues (for example kainate and ibotenate) elicit a pattern of neuronal degeneration that is similar in many respects to that observed in Huntington's disease. In this disease there is a progressive degeneration of most types of intrinsic neuron but somatostatin and neuropeptide Y levels are increased 3-5-fold. This may be attributed to the selective preservation of a sub-class of striatal aspiny neurons, in which these two peptides are co-localized together with the enzyme NADPH-diaphorase. Beal et al. reported recently that following intrastriatal injections of quinolinic acid in rats, medium-sized aspiny neurons were selectively preserved and they suggested that quinolinic acid which is found in human brain might cause the neuronal degeneration seen in Huntington's disease. We have used immunocytochemical and enzyme histochemical techniques to examine this selective toxicity but find no evidence to support this finding. We conclude that there are substantial differences between the immunocytochemical changes detected in postmortem Huntington's disease brain and those following quinolinic-acid-induced degeneration.     

Only full-sibling families evolved eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. The paper by Nowak et al. has the evolution of eusociality as its title, but it is mostly about something else. It argues against inclusive fitness theory and offers an alternative modelling approach that is claimed to be more fundamental and general, but which, we believe, has no practical biological meaning for the evolution of eusociality. Nowak et al. overlook the robust empirical observation that eusociality has only arisen in clades where mothers are associated with their full-sibling offspring; that is, in families where the average relatedness of offspring to siblings is as high as to their own offspring, independent of population structure or ploidy. We believe that this omission makes the paper largely irrelevant for understanding the evolution of eusociality.     

Kin selection and eusociality

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Hamilton described a selective process in which individuals affect kin (kin selection), developed a novel modelling strategy for it (inclusive fitness), and derived a rule to describe it (Hamilton's rule). Nowak et al. assert that inclusive fitness is not the best modelling strategy, and also that its production has been "meagre". The former may be debated by theoreticians, but the latter is simply incorrect. There is abundant evidence to demonstrate that inclusive fitness, kin selection and Hamilton's rule have been extraordinarily productive for understanding the evolution of sociality.     

内蒙古野豌豆属7种2变种染色体核型研究

本文研究了内蒙古野豌豆属7种2变种的染色体核型,其中Vicia pseudorobus,V.costata,V.gi-gantae,V.japonics,V.amaena ver.oblangifotia的核型为首次报道;同时对该属的染色体基数与核型之间的关系进行了讨论,认为其染色体基数与核型组成及结构特征之间具有一定相关性.     

代理可转换认证加密方案的改进

基于代理签名与可转换认证加密方案,任等(2005)提出了一种代理可转换认证加密和门限代理签名方案.在此指出了他们的方案是不安全的,原始签名人能够对任意的消息伪造有效的代理可转换认证加密签名.进一步,给出了改进方案以弥补他们方案的安全性缺陷.     

益母草的染色体组型研究

本文研究了益母草的核型,结果表明,益母草的体细胞染色体数目2n=20,核型公式为K(2n)=20=12m(2SAT) 8sm。均属中部着丝点和亚中部着丝点染色体,第6对染色体具随体。并与已报道过的该种核型作了比较研究。     

Inclusive fitness in evolution

Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. For over fifty years, the evolution of social behaviour has been guided by the concept of inclusive fitness as a measure of evolutionary success. Nowak et al. argue that inclusive fitness should be abandoned. In so doing, however, they misrepresent the role that inclusive fitness has played in the theory of social evolution by which understanding social behaviour in a variety of disciplines has developed and flourished. By discarding inclusive fitness on the basis of its limitations, they create a conceptual tension which, we argue, is unnecessary, and potentially dangerous for evolutionary biology.     

贵州遵义下寒武统牛蹄塘组生物群中的海绵化石

遵义松林中南村下寒武统牛蹄塘组中下部,特别是下部黑色泥岩中产有大量的海绵骨针,形态多样,初步研究有多达10属以上的海绵动物,与澄江生物群的海绵相比,牛蹄塘组的海绵动物化石其组合特征以六射海绵动物为主,它的发现增添了寒武纪生物组成的信息,为海绵动物从晚新元古代的发生以至穿越寒武纪的演化过程及寒武纪生物大爆发的定性,量度提供了重要信息及资料,描述了4属2个种。1个相似种和1个未定种。Hyalosinica sp.;Saetaspongia densa Mehl et Reitner,1993;Leptomitus teretiusculus CHen,Hou et Lu.1989;Crumillospongia cf.biporosa Righy,1986,它们分属于海绵动物的六射海绵纲和普通海绵纲。