Pheromone orientation: role of internal control mechanisms

Male American cockroaches walk a zigzag path upwind toward a source of female sex pheromone. Although the maximum width of the pathway is regulated by the width of an odor plume, many turns are made before the edge of a wide plume is encountered. In addition to the pheromone regulation of the insect's orientation movements, an internal mechanism appears to influence the zigzag turning pattern.     

G protein signaling in yeast: new components, new connections, new compartments

Signaling by cell surface receptors and heterotrimeric guanine nucleotide-binding proteins (G proteins) is one of the most exhaustively studied processes in the cell but remains a major focus of molecular pharmacology research. The pheromone-response system in yeast (see the Connections Map at Science's Signal Transduction Knowledge Environment) has provided numerous major advances in our understanding of G protein signaling and regulation. However, the basic features of this prototypical pathway have remained largely unchanged since the mid-1990s. New tools available in yeast are beginning to uncover new pathway components and interactions and have revealed signaling in unexpected locations within the cell.     

Pheromone source location by flying moths: a supplementary non-anemotactic mechanism

After the wind was stopped in an insect flight tunnel, male oriental fruit moths continued to fly in zigzag fashion along a stationary pheromone plume. Their lateral excursions from the time-averaged pheromone plume were no greater without wind than in wind of 38 centimeters per second. When the pheromone plume was removed and the wind stopped, males initiated wider track reversals when they reached the pheromone-free area in still air than they had made while in the pheromone plume. This non-anemotactic mechanism of maintaining plume contact-possibly a special kind of klinotaxis-when coupled with the orthokinetic retinal velocity of apparent ground pattern motion, allowed males to reach the pheromone source area from 1 to 2 meters away without wind.     

Progress in studies of sex determination mechanisms and sex control techniques in Cynoglossus semilaevis (half-smooth tongue sole)

The Cynoglossus semilaevis (half-smooth tongue sole) is a marine flatfish of great commercial value for fisheries and aquaculture in China. It has a female heterogametic sex determination system (ZW/ZZ) and environmental factors can induce sex-reversal of females to phenotypic males, suggesting that it is a promising model for the study of sex determination mechanisms. Additionally, females grow much faster than males and it is feasible to improve the aquaculture production through sex control techniques. This paper reviews the progress in research on sex determination mechanisms research in our laboratory. We have completed whole-genome sequencing and revealed the genome organization and sex chromosome evolution of C. semilaevis. A putative male determining gene dmrt1 was identified and DNA methylation was verified as having a crucial role in the sex reversal process. Genetic maps and sex-specific biomarkers have been used in a marker-assisted selection breeding program and for differentiation of the fish sex. Development and improvement of sex control technologies, including artificial gynogenesis and production of breeding fry with high proportion of females, is also reviewed. These research advances have provided insight into the regulation of sex determination and enabled efficient sex management in artificial culturing of C. semilaevis.     

鱼类性别决定的遗传基础及性别控制技术在水产养殖中的应用

控制鱼类的性别比例在养殖中常常至关重要。在一些物种中,因为雌雄二态性的存在,单性群体养殖可以显著提高养殖效益。对某些种类来说,性别转变甚至是其生命周期必经的一部分,比如某些雌雄同体的种类,在生命开始时是一种性别,在一段时间后转变为另一种性别,许多鱼类的性别具有较强的可塑性。性别决定遗传结构的研究有利于控制性别比例和育种方案的实施。哺乳动物和鸟类具有高度保守的性别决定主基因,控制着一个保守的遗传网络通路,该通路负责性别决定与性腺分化。不同于哺乳动物和鸟类,鱼类的性别决定机制存在着巨大的多样性。本文综述了鱼类性别决定多样性的研究进展,并以水产养殖主养品种罗非鱼、大菱鲆为例介绍了性别控制在生产上的应用,以期为水产养殖业的发展提供参考。     

Saccharomyces cerevisiae: a diffusible sex factor

A hormone-like substance is secreted by alpha mating-type cells of heterothallic yeast strains. It induces in cells of the opposite mating type, a, a morphological change characteristic of the mating process. Secretion of this substance and mating ability have some common genetic determinants. In partially purified preparations, the substance has properties of an oligopeptide.     

Temperature sex reversal implies sex gene dosage in a reptile

Sex in reptiles is determined by genes on sex chromosomes or by incubation temperature. Previously these two modes were thought to be distinct, yet we show that high incubation temperatures reverse genotypic males (ZZ) to phenotypic females in a lizard with ZZ and ZW sex chromosomes. Thus, the W chromosome is not necessary for female differentiation. Sex determination is probably via a dosage-sensitive male-determining gene on the Z chromosome that is inactivated by extreme temperatures. Our data invite a novel hypothesis for the evolution of temperature-dependent sex determination (TSD) and suggest that sex chromosomes may exist in many TSD reptiles.     

The mitotic spindle: a self-made machine

The mitotic spindle is a highly dynamic molecular machine composed of tubulin, motors, and other molecules. It assembles around the chromosomes and distributes the duplicated genome to the daughter cells during mitosis. The biochemical and physical principles that govern the assembly of this machine are still unclear. However, accumulated discoveries indicate that chromosomes play a key role. Apparently, they generate a local cytoplasmic state that supports the nucleation and growth of microtubules. Then soluble and chromosome-associated molecular motors sort them into a bipolar array. The emerging picture is that spindle assembly is governed by a combination of modular principles and that their relative contribution may vary in different cell types and in various organisms.     

小菜蛾性信息素与性信息素结合蛋白、受体蛋白结合机理研究

【目的】研究小菜蛾性信息素与性信息素结合蛋白、受体蛋白之间作用的关键氨基酸残基和作用力类型,揭示小菜蛾识别性信息素的分子机制,为开发新型性诱剂和小菜蛾的无害化防治提供新思路。【方法】运用Discovery Studio 2.5对小菜蛾性信息素结合蛋白PxylPBP2和受体蛋白PxylOR4进行同源建模,运用程序包中LibDock模块进行分子对接,运用Calculate Energy模块计算复合物结合自由能,分析性信息素Z9-14∶AC与PxylPBP2和PxylOR4的结合模式及相互作用力。【结果】Thr9是PxylPBP2与Z9-14∶AC形成氢键的关键氨基酸残基,Z9-14∶AC易与PxylOR4中的Leu残基产生疏水作用力;PxylPBP2与Z9-14∶AC结合的主要驱动力是静电力,PxylOR4与Z9-14∶AC结合的主要驱动力是范德华力,溶剂化能均抑制Z9-14∶AC与PxylPBP2和Z9-14∶AC与PxylOR4的结合。【结论】小菜蛾性信息素受体蛋白和性信息素结合蛋白在识别和结合性信息素分子方面存在明显差异,性信息素受体蛋白与性信息素反应更灵敏、形成的复合物更稳定。     

TNF-R1 signaling: a beautiful pathway

Tumor necrosis factor (TNF) is a major mediator of apoptosis as well as inflammation and immunity, and it has been implicated in the pathogenesis of a wide spectrum of human diseases, including sepsis, diabetes, cancer, osteoporosis, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel diseases. The interaction of TNF with TNF receptor-1 (TNF-R1) activates several signal transduction pathways. A common feature of each pathway is the TNF-induced formation of a multiprotein signaling complex at the cell membrane. Over the past decade, many of the components and mechanisms of these signaling pathways have been elucidated. We provide an overview of current knowledge of TNF signaling and introduce an STKE Connections Map that depicts a canonical view of this process.     

Synthetic Juvenile Hormone: Induction of Sex Pheromone Production in Ips confusus

Topical application of 25, 50, or 100 micrograms of 10,11-epoxy-farnesenic acid methyl ester in peanut oil induced male Ips confusus to produce sex pheromone in the hindgut Malpighian tubule region. Twenty-four hours aftertreatment of male beetles with 100 micrograms of hormone, their hindgut Malpighian tubule extract was more attractive to female beetles in a laboratory bioassay than was extract from males producing pheromone naturally in ponderosa pine logs.     

Brassinosteroid signaling: a paradigm for steroid hormone signaling from the cell surface

Plants use the coordinated action of several small-molecule hormones to grow and develop optimally in response to a changing environment. Among these hormones are the brassinosteroids (BRs), the polyhydroxylated steroid hormones of plants. BRs bind a small family of leucine-rich repeat receptor kinases at the cell surface, thereby initiating an intracellular signal transduction cascade that results in the altered expression of hundreds of genes.     

Male Esterase 6 Catalyzes the Synthesis of a Sex Pheromone in Drosophila melanogaster Females

Esterase 6, a component of the seminal fluid of Drosophila melanogaster males, hydrolyzes cis-vaccenyl acetate, a lipid made only by males, to cis-vaccenyl alcohol. This reaction occurs in the female reproductive tract and is virtually complete within 6 hours after copulation. Both the alcohol and the acetate decrease the number of matings among pairs of virgin flies in which the female is treated topically with these substances. Although females tested 10 minutes after copulation elicit less courtship than virgin females, females tested 6 hours after copulation stimulate even less courtship if they received active esterase 6 in the seminal fluid of their respective mates. Either the alcohol or a derivative appears to be an antiaphrodisiac that decreases courtship elicited by inseminated females and thus reduces the probability of further mating. Thus the activity of the pheromone depends on a final reaction which occurs in the female, using both substrate and enzyme provided by the male.     

蜜蜂蜂王与雄蜂幼虫饥饿信息素鉴定及其生物合成通路

【目的】蜜蜂幼虫在饥饿状态下会通过释放特定信息素来向外界传递饥饿信号,称为蜜蜂幼虫饥饿信息素(hunger pheromone)。论文旨在研究西方蜜蜂(Apis mellifera)蜂王与雄蜂幼虫饥饿信息素化学成分及在幼虫体内的生物合成通路,明确蜜蜂幼虫与成年蜂之间的化学信息素交流机制。【方法】采集2日龄与4日龄西方蜜蜂蜂王与雄蜂幼虫及其食物,将其分为饥饿组、饲喂组与纯食物组。饲喂组幼虫平躺在预先准备好的食物表面,饥饿处理组则不提供食物。所有样品分别放入20 m L密封采样瓶中并在35℃条件下放置45 min。利用Needle trap技术从样品瓶中采集10 m L气体,富集气体中的挥发性化学物质。在气质联用进样口以250℃高温将富集的化学物质解离,并通过气质联用技术分析鉴定蜂王与雄蜂幼虫饥饿信息素。同时,采用RNA-Seq技术分析饥饿信息素在蜂王与雄蜂幼虫体内的生物合成通路及相关基因表达。【结果】从蜂王与雄蜂幼虫中分别分析鉴定出10种与9种信息素,其中蜂王幼虫含有一种特有的幼虫信息素——2-庚酮,且在蜂王食物中含量最高。E-β-罗勒烯在蜂王与雄蜂幼虫各饥饿组含量均显著高于其饲喂幼虫组与食物组,表明蜂王与雄蜂幼虫均以E-β-罗勒烯为其饥饿信息素。2日龄蜂王与雄蜂幼虫饥饿组E-β-罗勒烯含量均差异不显著,但4日龄蜂王幼虫饥饿组E-β-罗勒烯含量显著低于雄蜂幼虫组。其余8种信息素为肉豆蔻酸、棕榈酸、甲基棕榈酸脂、硬脂酸、棕榈油酸、十五烷酸、乙酸与乙酸乙酯,均未出现饥饿组高于其他两组的规律。其中乙酸乙酯与乙酸在食物组与饲喂组含量高于饥饿组,推测其可能来自于幼虫食物。RNA-Seq结果表明蜂王与雄蜂幼虫通过甲羟戊酸途径由乙酰辅酶A从头合成E-β-罗勒烯。发现Geranylgeranyl pyrophosphate synthase-like与Farnesyl pyrophosphate synthase等9个基因参与该通路,但在饥饿组与其饲喂组幼虫中表达差异均不显著。【结论】蜜蜂蜂王与雄蜂幼虫利用E-β-罗勒烯作为其饥饿信息素乞求食物,并且在体内从头合成E-β-罗勒烯。工蜂利用2-庚酮标记蜂王幼虫,但未对雄蜂幼虫进行标记。     

Environmental sex determination: interaction of temperature and genotype in a fish

Sex determination in an atherinid fish, the Atlantic silverside (Menidia menidia), is under the control of both genotype and temperature during a specific period of larval development. The sex ratios of the progeny of different females are variable and differ in their responsiveness to temperature. This demonstrates that sex ratio in fishes that normally have separate sexes can be influenced by the environment.