离体受精作为技术平台在被子植物有性生殖研究中的应用

被子植物的离体受精10a前在玉米中已获得成功,尽管目前只在玉米获得完全成功和小麦获得部分成功,但离体受精技术的研究成果非常显著。目前离体受精技术已被用于其他的研究,如用分离的精细胞和卵细胞筛选配子细胞的特异基因和蛋白质：研究合子细胞被激活的机理：用不同种植物的精、卵细胞体外融合进行新的远缘杂交尝试;利用合子细胞易分裂和胚胎发生特征探索用其作为转基因研究的受体细胞等。以离体受精技术为基础在高等植物发育生物学和生殖生物学领域的基础研究和应用探索显示了巨大潜力。介绍了离体受精技术在被子植物有性生殖的研究成果和应用前景,为研究和利用被子植物有性生殖过程中的生殖细胞特征提供线索。     

Effect of nitrogen fertilization of corn on the development, survivorship, fecundity and body weight of Peregrinus maidis (Hom., Delphacidae)

Abstract:  Corn plants, Zea mays L. cv. Saccharata 'Guardian' fertilized with low (100 mg N/l), medium (300 mg N/l) and high (500 mg N/l) nitrogen doses at three times per week were used to study the effect of foliar nitrogen on the development, survivorship, reproduction, intrinsic rate of increase and adult body weight of Peregrinus maidis (Ashmead), a serious pest and the vector of maize stripe tenuvirus and maize mosaic rhabdovirus in tropical and subtropical areas. The results showed that the higher nitrogen treatments resulted in the higher nitrogen concentrations in the plants. The insects that developed on corn plants receiving more nitrogen had a significantly shorter development time and higher immature survival rate and laid significantly more eggs. Plants with higher nitrogen concentration also resulted in significantly greater adult mass. Heavier body weight is advantageous because heavier adult females have greater daily oviposition rates than lighter ones. These life history parameters as well as population intrinsic rate of increase were positively correlated with the nitrogen levels in the treated plants. The differences of adult longevity and preoviposition period among different nitrogen treatments were also significant; however, no significant correlation was found between the nitrogen fertilization rate and adult longevity, as well as preoviposition period.     

Mating tactics in external fertilizers when sperm is limited

Among externally fertilizing animals in aquatic habitats, theproportion of a female's egg clutch that is successfully fertilizedoften falls below 100%. In many such species, particularly incoral reef fishes, males spawn daily at high frequencies, oftenwith little or no sperm competition. A major evolutionary problemfor such males is how best to allocate sperm over successivespawns. Females face the problem of ensuring complete fertilizationof their egg clutch. Here we model male and female mating tacticswhen daily sperm production is limited and with various assumptionsconcerning how differences in the number of sperm released duringa mating influence the number of eggs fertilized. The modelsreveal conditions under which males can maximize daily reproductivesuccess, either by releasing a fixed number of sperm duringall successive spawns or by matching sperm numbers to the clutchsize of their mates. These patterns of sperm allocation exertdifferent pressures on females, which may respond evolutionarilyby developing various mating tactics of their own.     

Aspects of the reproductive biology of the South African polychaete,Arenicola loveni loveni (Kinberg 1866)

Summary

The annual cycles of gametogenesis, spawning and fertilization biology were investigated in the South African polychaete Arenicola loveni loveni (Kinberg, 1866). Sexes are strictly separate (gonochoric) with a 1:1 ratio and gametogenesis takes place in the coelomic cavity. Reproduction is iteroparous and occurs during a synchronized annual epidemic spawning event during the summer months of February or March, which lasts no longer than 2 weeks at around the time of highest annual seawater temperatures. A slight inter-annual variation in spawning time was observed between 2003 and 2004. Annual fecundity was estimated as 311,200 (± 82,040 standard deviations) oocytes per female per year. Oocytes are arrested at prophase I of the first meiotic division and require a maturation step prior to spawning and subsequent fertilization. Mean spawned oocyte diameter was 141.16 μm ± 0.43 SE. Sperm develop as morulae in the coelomic cavity and also require a maturation step prior to spawning. Spawning can be achieved by injection of prostomial homogenate in both males and females and by injection with 8,11,14- e cosatrienoic acid for males and can be delayed by temperature manipulation. Oocyte maturation and sperm maturation can be induced in vitro by incubating in prostomial homogenate.     

A training program for noninvasive semen collection in captive western lowland gorillas (Gorilla gorilla gorilla)

Staff at Omaha's Henry Doorly Zoo devised a training program for noninvasive semen collection from three male gorillas. Trained behaviors, shaped using food rewards and verbal praise, enabled the trainer to perform a cursory physical examination and collect >270 semen samples during the study period. Ejaculate volume, sperm motility, and progressive forward motion were recorded. Two of the gorillas regularly produced semen samples that were cryopreserved. Frozen semen from one gorilla was successfully used in an assisted reproductive procedure. The training program may be used as a guideline for other institutions to create similar programs. Zoo Biol 17:143–151, 1998. © 1998 Wiley-Liss, Inc.     

海藻有性繁殖生态学研究进展

由于研究技术与方法的不断改进 ,人们对海藻 (seaweeds)早期生活史方面的研究兴趣日益增大。评述了近年来海藻有性繁殖过程中配子释放和受精生态学问题。到达一定生理状态的海藻 ,通过对环境暗示应答而诱导配子形成。海藻生殖器官感受另一些特定的环境条件 ,通过有关信号传递机制 ,触发配子释放。海藻配子释放的时间及其所需的环境条件 ,依不同的种类而变化。配子同步释放以及各种适当的环境条件提高了受精频率和受精成功率 ,有利于受精的各种生物的和非生物的因素组合 ,形成了“机会窗 (the window of opportunity)”的概念。近年来的研究表明 ,海藻 (特别是红藻 )的自然受精成功率比以前所认为的要高得多。受精后合子 (胚 )的散布、集落与附着显著地影响其生存以及种群动态。对今后值得进一步研究的方面作了展望     

Induction of a fertile mating in a red ruffed lemur (Varecia variegata rubra) using pregnant mare serum gonadotropin

Pregnant mare serum gonadotropin (PMSG) was administered to an adult female red ruffed lemur (Varecia variegata rubra) as part of a medical evaluation to determine the cause of reproductive failure. Successful fertilization, pregnancy, and parturition occurred following PMSG treatment. This report documents an approach to evaluating reproductive failure in an endangered primate species and illustrates the value of collecting objective data on all individuals in a colony for retrospective and comparative analysis. Data from basic and applied research on a variety of species were synthesized to establish a logical protocol for fertility evaluation of an individual. The use of PMSG to induce estrus, ovulation, or fertilization has not been documented for an endangered primate species.     

银杏传粉生物学研究进展

银杏(Ginkgo biloba L.)是最古老裸子植物之一,其传粉受精过程表现出许多特殊的原始性状和特征,在种子植物的系统演化上具有重要研究价值;同时,银杏种实经济价值高,但栽培上由于授粉受精不良而导致落花落果现象严重,因此了解银杏传粉生物学特性对于其种实的优质高产具有实际意义.本文从银杏雌雄株开花物候学、雌雄花形态结构特征、花粉和胚珠发育进程、花粉和胚珠生物学特性、传粉机制及花粉在胚珠内萌发生长进程等方面,对银杏传粉生物学相关研究进行综述,为银杏的系统演化、授粉受精和种实发育研究提供参考.     

The adaptive background of nannandry: dwarf male distribution and fertilization in the moss Homalothecium lutescens

Dwarf males (nannandry) occur in many unrelated, mostly aquatic, groups of organisms. Among land plants they are unique to bryophytes. In this study our aim was to explain variation in frequency of dwarf males and fertilization within populations in the moss Homalothecium lutescens. We compared parameters related to dwarf male presence and sporophyte production in 90 colonies from three localities. Dwarf male density was positively associated with colony moisture at two of the localities, suggesting increased spore germination and dwarf male survival with moist conditions. At one of these localities, dwarf male density was also positively associated with the presence of perichaetia (female sexual branches). Dwarf male density and fertilization frequency were positively associated in two of the localities. Furthermore, in one population, fertilization was also positively associated with canopy cover, which could be attributed to improved nutrient status as a result of throughfall, increased sperm‐dispersal efficiency because of larger water drops, or more favourable moisture conditions as a result of shading. Nannandry thus appears to strongly reduce the problem of short fertilization distances in bryophytes, but the presence of water is still critical because the dwarf males are dependent on a certain level of humidity for recruitment and/or development. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 74–84.     

Effects of Progesterone,Testosterone, and Estrogen on Sexual Reproduction of the Rotifer Brachionus calyciflorus

It is known that some vertebrate reproductive hormones have effects on rotifer reproduction, but little is known about their effects in combination. This motivated us to examine the effects of waterborne progesterone (P), testosterone (T), and estradiol (E) on reproduction of the rotifer Brachionus calyciflorus, comparing exposures to single hormones and mixtures with a total concentration of 1000 μg/L. Asexual population growth (r) was high in all treatments, ranging from 1.28 to 1.43 d^–1 (P‐E), and from 0.99 to 1.22 d^–1 (P‐T). These results indicate that E, P, or T alone, or in combinations of P‐E and P‐T totaling 1000 µg/L, and the 3‐way combination P‐E‐T at 1200 µg/L do not reduce the asexual reproduction of B. calyciflorus. However, significant effects were detected on sexual reproduction with exposure to these hormone concentrations. Exposure to P‐T and P‐E at 1000 μg/L decreased resting egg production significantly. Analysis of mating indicated that fertilization was 5.3 times higher in the control than in treatments where females were exposed to 500 µg/L each P‐T. A similar result was observed when both females and males were exposed to 500 µg/L each of P‐T. When males alone were treated with 500 µg/L each of P‐T, there was no significant difference in male fertility compared to the control. These results suggest that B. calyciflorus uses oxidized sterols similar to P and T to regulate sexual reproduction and waterborne exposure of females to these compounds interferes with fertilization and resting egg production. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

LIGHT AND SCANNING ELECTRON MICROSCOPIC INVESTIGATIONS OF SEXUAL REPRODUCTION IN HYDRA CARNEA

In the freshwater hydrozoan Hydra carnea, the egg, matured and grown between the mesoglea and the epitheliomuscular cells of the ectoderm, is extruded after the emission of the second polar body. Surrounded by a clear jelly layer the egg remains attached to the polyp. Sperm which are released from the testicular sacs of male polyps are attracted by the egg. The jelly layer is penetrated only at the site of emission of the polar bodies by sperm which lack a structurally distinct acrosome. One sperm fuses with the egg at that site where the female pronucleus is found to lie close to the egg membrane. After fertilization and cleavage an acellular embryotheca is secreted by the blastomeres. These events were investigated by light and scanning electron microscopy.     

Development of an experimental laboratory fertilization protocol for the South African abalone,Haliotis midae (Linnaeus 1758)

In this study, effective gamete concentrations, egg viability, and fertilization volumes were evaluated for Haliotis midae (L.). Sperm concentrations between 5?×?10³ and 5?×?10⁴?mL^?1 (p?>?0.05) consistently resulted in high hatch-out rates (96?±?1%). At concentrations higher than 5?×?10⁵?mL^?1, hatch-out rates decreased to 69?±?7% (p??1 resulted in high fertilization rates, with 50?eggs?mL^?1 being the ideal concentration for fertilization in H. midae. Egg viability was consistently high up to 100?min post-spawning, with a decrease in hatch-out success, when eggs were fertilized 120?min post-spawning. Fertilization volumes did not affect successful hatch-out. The results from this study can be implemented by South African abalone farms to increase hatch-out rates and subsequent culture. It can also be used as basis for the development of fertilization protocols in other marine invertebrate species.     

高等植物受精过程中雌-雄相互作用的分子调控机制

从广义上讲,被子植物的受精过程是指花粉粒落到柱头上萌发形成花粉管,花粉管穿过柱头沿着引导组织生长进入子房内,最终在胚囊中实现精细胞与卵细胞以及中央细胞分别融合从而起始胚胎和胚乳的发育．被子植物的精细胞由于不具有鞭毛而无法自由移动,因此在受精过程中需要借助于花粉管来将精细胞运送到胚囊中．花粉管通过与雌性的孢子体组织之间的相互作用和识别将精细胞准确地运送到胚珠附近,而最终将精细胞准确地运送到胚囊内的过程则是受到了雌配子体细胞的控制．可以说,受精的成功实现有赖于雌性和雄性细胞之间的持续的识别和相互作用,这种互作具有多样性和阶段特异性．本文将主要综述被子植物受精过程中花粉粒以及花粉管与多种雌性孢子体组织以及雌配子体之间的信号互作研究．     

Does seasonal reproduction occur at the optimal time for fertilization in the polychaetes Arenicola marina L. and Nereis virens Sars?

Summary

Many marine invertebrates exhibit highly seasonal and synchronised reproduction, with offspring production often being confined to just two or three days each year. Several models have been proposed to explain the fitness benefits of this reproductive pattern, many of which assume enhanced offspring survival due to temperature constraints placed on fertilization and development at other times of the year. In this investigation the temperature limits and optimum for fertilization were determined for two polychaete species, Arenicola marina and Nereis virens. These two polychaete species are exposed to the same environmental conditions throughout the year, yet breed at very different times. Other seasonal impacts on fertilization, i.e., reduced salinity due to rainfall and the effect of sub-zero temperatures on sperm of A. marina, were also investigated. In both A. marina and N. virens fertilization success was significantly influenced by temperature, with the maximum success recorded at 15–18°C. The ambient seawater temperature at the time of natural spawning for both worms is around 10°C, which means that both species are spawning right at the lower limit for maximum fertilization. Salinity and exposure of A. marina sperm to sub-zero temperatures were also found to influence fertilization success, but only at levels that would not be experienced by these polychaetes under natural conditions at the time of spawning. These results suggest there must be additional selective pressures acting on the fitness of these two polychaetes causing A. marina to breed later than, and N. virens to breed earlier than, the optimum time for fertilization. A. marina apparently waits as late as possible to maximise adult fecundity and survival. N. virens breeds as soon as it can achieve high fertilization to maximise larval and juvenile competitiveness.     

The effect of dietary lipid content and stress on egg quality in farmed Atlantic cod Gadus morhua

The present study assessed differences in fecundity and egg quality from Atlantic cod Gadus morhua fed isoproteic diets containing 13% fat (low fat, LF) or 20% fat (high fat, HF) and either stressed or left unstressed as a control over the spawning season. Each diet was fed to triplicate groups of G. morhua from June 2009, through to first maturation and spawning. In January 2010 sub-groups of G. morhua were moved to land-based spawning tanks where the experimental trial was carried out. At the start of the experiment, G. morhua fed the high-fat diet were significantly larger than G. morhua fed low-fat diet. These differences were maintained through the spawning season, although with a loss of mass in both dietary groups. Relative fecundity through the season was significantly lower in stressed G. morhua fed LF compared to unstressed G. morhua fed the same diet. Stressed G. morhua had a higher variability in weekly amount of eggs spawned, spawning occurred more irregularly, and the spawning period lasted longer than in unstressed G. morhua. Several egg quality variables were also affected: eggs from G. morhua fed LF and exposed to stress had lower fertilization and hatching rates compared to the unstressed G. morhua fed the same diet as well as all G. morhua fed HF. Gadus morhua fed a low-fat diet appeared less tolerant to stress than fish fed a high-fat diet.     

Reproductive biology of the rosylip sculpin, an intertidal spawner

Rosylip sculpin Ascelichthys rhodorus spawned in the intertidal during the winter in the north‐eastern Pacific. Large numbers of males typically congregated at spawning sites, where females deposited clutches. The mating system of this species was external fertilization and group spawning at specific oviposition sites under boulders in the intertidal, and no alternative male mating strategies. Males were abundant at sites while oviposition was occurring, and most abandoned the sites as spawning tapered off seasonally despite the presence of developing clutches. Experimental removal of males from sites suggested that males provided some short‐term benefits to clutches, with catastrophic loss of clutches significantly lower when males were present. The large number of males at an oviposition site and histological evidence indicating high sperm production and storage of sperm prior to release suggest a high level of sperm competition in this species. This spawning pattern appears to differ in substantial ways from any other reported fish mating system.     

Transgenic goats produced by DNA pronuclear microinjection of in vitro derived zygotes

This study was undertaken to investigate various factors affecting the outcomes of in vitro fertilization (IVF) of oocytes retrieved by laparoscopic ovum pick-up (LOPU) technique from prepubertal and adult goats, as well as to evaluate the developmental competence of in vitro produced embryos. Oocyte-cumulus complexes recovered by LOPU from donors stimulated with gonadotrophins were matured in vitro. Fresh semen was used for IVF following various capacitation treatments. In vitro produced zygotes were either cultured to assess in vitro development or were transferred into recipients for full term development. The results indicated that successful IVF of the goat oocytes was affected by factors such as sperm capacitation treatment, oocyte quality, and abundance of cumulus cells on zona pellucida. Oocytes from both prepubertal and adult goats demonstrated similar full term developmental competence despite the fact that in vitro developmental rates were lower for prepubertal goats. The births of transgenic offspring demonstrated that the established LOPU-IVF technology combined with pronuclear microinjection can be successfully used to produce transgenic goats.     

Functional interplay between ribosomal protein paralogues in the eRpL22 family in Drosophila melanogaster

ABSTRACT

Duplicated ribosomal protein (RP) genes in the Drosophila melanogaster eRpL22 family encode structurally-divergent and differentially-expressed rRNA-binding RPs. eRpL22 is expressed ubiquitously and eRpL22-like expression is tissue-restricted with highest levels in the adult male germline. We explored paralogue functional equivalence using the GAL4-UAS system for paralogue knockdown or overexpression and a conditional eRpL22-like knockout in a heat- shock flippase/FRT line. Ubiquitous eRpL22 knockdown with Actin-GAL4 resulted in embryonic lethality, confirming eRpL22 essentiality. eRpL22-like knockdown (60%) was insufficient to cause lethality; yet, conditional eRpL22-like knockout at one hour following egg deposition caused lethality within each developmental stage. Therefore, each paralogue is essential. Variation in timing of heat-shock-induced eRpL22-like knockout highlighted early embryogenesis as the critical period where eRpL22-like expression (not compensated for by eRpL22) is required for normal development of several organ systems, including testis development and subsequent sperm production. To determine if eRpL22-like can substitute for eRpL22, we used Actin-GAL4 for ubiquitous eRpL22 knockdown and eRpL22-like-FLAG (or FLAG-eRpL22: control) overexpression. Emergence of adults demonstrated that ubiquitous eRpL22-like-FLAG or FLAG-eRpL22 expression eliminates embryonic lethality resulting from eRpL22 depletion. Adults rescued by eRpL22-like-FLAG (but not by FLAG-eRpL22) overexpression had reduced fertility and longevity. We conclude that eRpL22 paralogue roles are not completely interchangeable and include functionally-diverse roles in development and spermatogenesis. Testis-specific paralogue knockdown revealed molecular phenotypes, including increases in eRpL22 protein and mRNA levels following eRpL22-like depletion, implicating a negative crosstalk mechanism regulating eRpL22 expression. Paralogue depletion unmasked mechanisms, yet to be defined that impact paralogue co-expression within germ cells.     

EVIDENCE FOR SEXUAL REPRODUCTION IN THE MARINE DINOFLAGELLATES, PYROCYSTIS NOCTILUCA AND PYROCYSTIS LUNULA (DINOPHYTA)

Evidence for sexual reproduction was observed in two oceanic dinoflagellate species, Pyrocystis noctiluca Murray ex Haeckel and Pyrocystis lunula (Schütt) Schütt. Observations suggest that cells underwent fertilization as opposed to cell division because of the following: first, fusing cells had a conspicuous pore (fusion pore) connecting the two gametes; dividing cells lacked this feature. In culture, about 0.1% of P. noctiluca cells had a fusion pore, which serves as a possible site for gamete recognition on the cell wall. Second, we document a temporal progression of plasmogamy and karyogamy. Fusion events in both species were observed at the beginning of the day, whereas division stages were most apparent at the end of the day.