Sexual Interaction in Heterothallic Strains of Closterium peracerosum-strigosum-littorale: Partial Characterization of a Male-Specific Sexual Pheromone, Protoplast-Releasing Substance

A sexual pheromone, named the protoplast releasing substance (PRS), was formed by mating type minus cells. PRS activates mating type plus cells and results in the release and fusion of protoplasts within distended conjugation-papilla in paired cells and in the release and disruption of protoplasts in unpaired mating type plus cells. In an agar barrier system, the activation of mating type plus cells was markedly inhibited by treatment with pronase (5-10 micrograms per milliliter), proteinase (100 micrograms per milliliter), and α-mannosidase (10 micrograms per milliliter). Trypsin (10-100 micrograms per milliliter) had no effect on the activation in the agar barrier system. The results suggest that PRS is a glycoprotein with pronase-sensitive and trypsin-insensitive structure.     

Protein and RNA Synthesizing Activities during Sexual Process of Heterothallic Closterium

Protein and RNA synthesizing activities increased markedly during the mating process and decreased during the maturation stage of zygotes in heterothallic strains of Closterium peracerosum-strigosum-littoale, KAS-4-29 (mating-type minus) and KAS -4-30 (mating-type plus) and a homothallic Closterium acerosum. Different proteins were synthesized at the different stages of the mating process, suggesting that a sequential expression and repression of mating genes occur for the mating-specific protein synthesis during the sexual reproduction.     

Intercellular Communication During Sexual Reproduction of Closterium (Conjugatophyceae)

Closterium were reviewed. In the case of Closterium peracerosum-strigosum-littorale complex, two sex-specific pheromones and their receptors were involved in sexual reproduction. These pheromones were glycoproteins and the expression of corresponding genes was critically regulated by the sex and environmental conditions. In the case of Closterium ehrenbergii, chemotactic and sexual cell division-inducing activities for mating-type plus cells were detected and characterized. Although many processes remain to be elucidated, the present results will be helpful for understanding not only the mode of sexual reproduction in Closterium but also the variety of intercellular communication in the plant kingdom especially during sexual reproduction. Received 10 June 2000/ Accepted in revised form 6 July 2000     

Interaction between Different Mating Types in Heterothallic Strains of Closterium peracerosum-strigosum-littorale: Effects on Expansion of Colony

When Closterium cells were embedded in an agar disk which wasplaced on an agar plate, the cells migrated out of the agardisk and formed a circular colony on the surface of the agarplate. Expansion of the colony was affected by interaction betweendifferent mating type cells. (Received November 20, 1982; Accepted May 6, 1983)     

Purification and Characterization of a Novel Sex Pheromone that Induces the Release of Another Sex Pheromone during Sexual Reproduction of the Heterothallic Closterium peracerosum-strigosum-littorale Complex

A sex pheromone, PR-IP Inducer, which is released from mating-typeminus cells of Closterium, was purified by monitoring its biologicaleffect on the induction of the release of protoplast-release-inducingprotein (PR-IP) from mating-type plus cells. The purified PR-IPInducer had an apparent molecular mass of 22 kDa and of 18.7kDa as determined by SDS-PAGE and mass-spectrometric analysis,respectively. Staining with periodic acid-Schiff reagent indicatedthat PR-IP Inducer included a glycan chain. From the analysisof a dose-response curve, it seemed that PR-IP Inducer was ableto exert its activity over quite wide range of concentrations(1 x 10^–10–3 x 10^–7 M). It appears that PR-IPInducer is a novel glycoproteinaceous pheromone, as is PR-IP,and that it exerts its effect at the earliest stages of thesexual reproduction of the Closterium peracerosum-strigosum-littoralecomplex. ¹Recipient of a Fellowship for Japanese Junior Scientists fromthe Japan Society for the Promotion of Science.     

掌状冠盖藻有性生殖过程中的光效应和光受体

以采自厦门海滨的中心硅藻掌状冠盖藻为实验材料,研究光对其有性生殖的影响。结果表明：诱导该藻有性生殖发生的临界日长为12h,其性化强度随光期加长与光强加大而增强,红光比白光的性分化诱导能力强,蓝光无诱导效应,设置光强度低于光合补偿点的白光或红光的加长光期,无论置于主光期之前或之后均能启动该藻性化反应,蓝光无效。从而获知,该藻至现长日照植物特征,光周期反应特性类似于光控类型,但却不具有夜中断反应,有性生殖过程中可能受红光受体的调控。     

Detection and Evaluation of an Inducer of a Diffusible Mating Pheromone of the Heterothallic Closterium peracerosum-strigosum-littorale Complex

When mating-type plus cells of the Closterium peracerosum-strigosum-littoralecomplex were incubated in nitrogen-deficient medium obtainedfrom a 24-h-old mixed culture of mating-type plus and mating-typeminus cells, protoplast-release-inducing activity specific formating-type minus cells was detected in the medium. When mating-typeplus cells were incubated in the medium from a culture of exclusivelymating-type minus cells, protoplast-release-inducing activitywas also detected. These results suggested the existence ofa substance, released from mating-type minus cells, that hasthe ability to make mating-type plus cells release protoplast-release-inducingprotein (PR-IP). We designated it PR-IP Inducer. The PR-IP Inducerwas constitutively released from mt^– cells in the light.The PR-IP Inducer was heat-labile and had a relative molecularweight of 10,000 on gel filtration. We suggest that the PR-IPInducer is also a pheromonal substance that plays a role inthe initial events in the sexual communication of this Closteriumcomplex. (Received April 26, 1993; Accepted July 15, 1993)     

Light dependency of the mating process in Closterium acerosum

Sexual cell division and activation of gametangial cells forconjugation in Closterium acerosum were induced by light. L₂₀₀cells conjugated at maximum level under the following conditions;(i) a light intensity higher than 1,000 lux in a 16-hr lightand 8-hr dark regime and (ii) an illumination time longer than12 hr at 3,000 lux. L₂₀₀ cells also conjugated under continuousillumination at 3,000 lux. The action spectrum for the activation of gametangial cellshad peaks around 450, 611 and 665 nm. 3-(4'-Chlorophenyl)-l,l-dimethylurea (CMU) inhibited the accumulationof carbohydrates and sexual cell division at 10^–5 M andthe activation of gametangial cells for conjugation at 10^–4M. (Received August 15, 1977; )     

Origins of Eukaryotic Sexual Reproduction

Sexual reproduction is a nearly universal feature of eukaryotic organisms. Given its ubiquity and shared core features, sex is thought to have arisen once in the last common ancestor to all eukaryotes. Using the perspectives of molecular genetics and cell biology, we consider documented and hypothetical scenarios for the instantiation and evolution of meiosis, fertilization, sex determination, uniparental inheritance of organelle genomes, and speciation.The transition from prokaryote to protoeukaryote to the last eukaryotic common ancestor (LECA) entailed conservation, modification, and reconfiguration of preexisting genetic circuits via mutation, horizontal gene transfer (HGT), endosymbiosis, and selection, as detailed in previous articles of this collection. During the course of this evolutionary trajectory, the LECA became sexual, reassorting and recombining chromosomes in a process that entails regulated fusions of haploid gametes and diploid → haploid reductions via meiosis. That the LECA was sexual is no longer a matter of speculation/debate as evidence of sex, and of genes exclusively involved in meiosis, has been found in all of the major eukaryotic radiations (Brawley and Johnson 1992; Ramesh et al. 2005; Kobiyama et al. 2007; Malik et al. 2008; Phadke and Zufall 2009; Fritz-Laylin et al. 2010; Lahr et al. 2011; Peacock et al. 2011; Vanstechelman et al. 2013).We propose that the transition to a sexual LECA entailed four innovations: (1) alternation of ploidy via cell–cell fusion and meiosis; (2) mating-type regulation of cell–cell fusion via differentiation of complementary haploid gametes (isogametic and then anisogametic), a prelude to species-isolation mechanisms; (3) mating-type-regulated coupling of the diploid/meiotic state to the formation of adaptive diploid resting spores; and (4) mating-type-regulated transmission of organelle genomes. Our working assumption is that the protoeukaryote → LECA era featured numerous sexual experiments, most of which failed but some of which were incorporated, integrated, and modified. Therefore, this list is not intended to suggest a sequence of events; rather, the four innovations most likely coevolved in a parallel and disjointed fashion.Once these core sexual-cycle themes were in place, the evolution of eukaryotic sex has featured countless prezygotic and postzygotic variations, the outcome being the segregation of panmictic populations into distinct species with distinctive adaptations.For additional reviews on the evolution of sex, the interested reader is referred to Goodenough (1985), Dacks and Roger (1999), Schurko et al. (2009), Wilkins and Holliday (2009), Gross and Bhattacharya (2010), Lee et al. (2010), Perrin (2012), and Calo et al. (2013).     

鲁中山区东亚三角头涡虫有性生殖过程研究初报

于2005年3-5月、9～11月对生活于鲁中山区的东亚三角头涡虫（Dugesia japonica）的有性生殖过程进行了研究,发现鲁中山区东亚三角头涡虫1年只有1次有性生殖过程。卵囊产出的高峰在4月,卵囊孵化与种群密度最高峰在5月,其有性生殖过程与温度、食物、虫体大小密切相关。经实验观察1个卵囊最多能孵出涡虫幼体10条,最少3条。     

被子植物有性生殖过程中的细胞程序死亡

细胞程序死亡是植物发育过程中的一种普遍现象。早就认识到高等植物生殖器官中一些细胞的死亡对植物有性生殖具有重要作用。这些细胞的死亡过程与动物组织中的细胞程序死亡基本相同。但植物体内诱导生殖细胞程序死亡的信号及其传导系统则显示出其特点 ,有些还表现出雌、雄性细胞的相互作用。探索植物生殖过程中的细胞程序死亡现象将有利于澄清植物生殖过程中的一些机理问题 ,使过去的细胞学研究结果深入到分子水平进行探讨     

阿拉伯半乳糖蛋白在被子植物有性生殖中的作用

阿拉伯半乳糖蛋白(arabinogalactan-proteins,AGPs)是一类主要分布在细胞表面和胞外基质中的糖蛋白.它们在植物的雄性器官(花粉、花粉管、精细胞)、雌性器官(柱头、花柱、子房)和胚胎(合子胚和体细胞胚)等组织和细胞中均有大量的表达.大量研究表明AGPs在被子植物有性生殖过程中起着非常重要的作用,既可能参与花粉管粘附、营养、传导或提供信号的作用,也可能参与受精过程中配子识别和受精后胚胎的发育与分化等过程.该文就其分子结构、特性以及在植物有性生殖过程中各种器官和组织内的表达和功能研究进展做了较为全面的概述.     

Hormonal Control of Sexual Differentiation and Reproduction in Crustacea

SYNOPSIS. Sexual differentiation in malacostracan Crustaceais controlled by the androgenic gland hormone (AGH). In males,the primordial androgenic glands (AG) develop and AGH inducesmale morphogenesis. In females, the primordial AG does not developand the ovaries differentiate spontaneously. Implantation ofthe AG into females yields various results, showing that thesensitivity to AGH differs with the species and the receptiveorgans. Purified AGH of the isopod Armadillidium vulgare consistsof at least two molecular forms, which exist as monomeric proteinswith molecular weights of 17,000 ± 800 and 18,300 ±1,000 Da and with isoelectric points of about 4.5 and 4.3, respectively.The antiserum raised against purified AGH makes it possibleto measure AGH activity by immunoassay. Neurohormones control male and female reproduction. In males,they are involved in the maintenance of the male germinativezone and the control of AG activity. In females, the secondaryvitellogenesis is controlled by the vitellogenesis-inhibitinghormone (VIH) and the vitellogenesis- stimulating hormone (VSH).VIH isolated from the lobster Homarus americanus is a peptidewith a molecular weight of 9,135 Da and shows homology to thecrustacean hyperglycemic hormone and moltinhibiting hormone.Involvement of the molting hormone and the juvenile hormone-likecompound in the secondary vitellogenesis have also been suggested.In the amphipod Orchestia gammarella, the vitellogenesis- stimulatingovarian hormone (VSOH) seems to control vitellogenin synthesis