Methyl farnesoate inhibition of late stage ovarian development and fecundity reduction in the black tiger prawn, Penaeus monodon

There is mounting evidence that the terpenoid hormone methyl farnesoate (MF) plays important roles in regulating reproductive processes in crustaceans. To gain further information on its roles and possible modes of action, MF was orally administered to ablated Penaeus monodon at a concentration of 5.5 μg per gram of diet, and a range of reproductive performance criteria measured. Results confirmed that MF plays a role in the reproductive process of this species. Specifically, under the conditions of this study, MF inhibited late stage ovary development and reduced fecundity in ablated prawns. The impact of the artificial diet (without additional MF) relative to a squid–mussel diet, was also assessed in this study and although it increased the quality of larvae produced, it also increased inhibition of late stage ovary development. Thus while the current study has increased our knowledge of MF by isolating an ovary developmental stage at which MF regulates reproduction in P. monodon, factors that determine the extent of its effect and whether it has a stimulatory or inhibitory effect, remain unknown. Until these factors are identified, the application of MF as a means of predictably manipulating egg production in captive prawns remains problematic.     

Thyroid hormone modulation of ovarian recrudescence of air-breathing catfish Clarias gariepinus

In the present study, thiourea-induced thyroid hormone depletion and thyroxine (T₄) ‘overdose’ were used as a strategy to understand the influence of thyroid hormones on ovarian recrudescence of juvenile (3-months-old), immature (8-months-old) and adult (1-year-old) air-breathing catfish, Clarias gariepinus. Thiourea-induced thyroid hormone depletion in juvenile catfish impaired ovarian development, but no significant effect was observed in immature catfish and during late stage of ovarian recrudescence of mature catfish. T₄ treatment in females undergoing late stages of ovarian recrudescence induced rapid oocyte growth by promoting its early entry into maturational phase as evident from the presence of more number of vitellogenic and post-vitellogenic follicles, decrease in aromatse immunoreactivity and reduced estradiol–17β levels. Hence, thyroid hormones have an important role to play during early stages of ovarian development and vitellogenesis of catfish and also indicating that thyroid has a stage dependent effect on ovary.     

Gonadotropins and their paracrine signaling network in the zebrafish ovary

Pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), play fundamental roles in vertebrate ovarian development and function. However, there has been an increasing body of evidence that the actions of FSH and LH are mediated or modulated by a variety of locally produced peptide or protein factors, which form an intimate regulatory network within and between the ovarian follicles. In the past few years, a variety of growth factors have been identified and characterized in the zebrafish ovary including activin and epidermal growth factor (EGF), which are important components of the intraovarian communication network. To understand how this local network interacts with the gonadotropins from the pituitary, we have recently cloned and characterized all the subunits of zebrafish FSH and LH from the pituitary as well as their receptors (FSHR and LHR) from the ovary. Using the Chinese hamster ovary (CHO) cells as the bioreactor, we have produced recombinant zebrafish FSH and LH with biological activities. With the recombinant hormones available, the functions of zebrafish FSH and LH in the ovary and their interactions with the local factors will be an important issue to address in the future. This review briefly summarizes some recent work from our laboratory and others on both gonadotropins and their potential intraovarian signaling factors in the zebrafish.     

色素万寿菊杂交母本未授粉子房培养

以色素万寿菊雄性不育株未授粉子房为外植体,比较研究子房发育期、高低温处理和生长调节剂组合对愈伤组织诱导和分化的影响。结果显示:发育6~10 d,花丝刚好露出花萼,顶部呈圆柱状的花蕾愈伤组织诱导效果最好,为79.2%;低温预处理3 d,高温培养5 d有利于愈伤组织诱导;MS+2,4-D 0.5 mg/L+NAA0.5 mg/L+6-BA 0.5 mg/L+KT 0.5 mg/L为愈伤组织诱导最佳培养基,诱导率高达85.8%;NAA 1.0 mg/L+6-BA3.0 mg/L为不定芽分化适宜培养基,分化率达77.6%;1/2MS+NAA 0.2 mg/L为生根适宜培养基,生根率93.5%。本研究可为建立高效单倍体培养体系以及单倍体育种技术提供基础性资料。     

三种多胺在苹果开花及坐果初期的生理作用

研究了苹果开花过程中花药、幼果（花托和子房）和贮藏花粉内源腐胺（Put）、亚精胺（Spd）、精胺（SPin）的含量变化及外源3种多胺对花粉萌发、雌蕊寿命和坐果的影响。结果表明：在开花过程中，花药中3种多胺的含量逐渐降低，花粉中的含量在贮藏期间和荫芽率同步降低；3种多胺浴液浸泡的花粉，其萌发率和花粉管长度极显著提高和增长；从蕾期到第一次生理落果，幼果多胺含量呈下降趋势，但受精幼果比未受精幼果的下降速度缓慢；第一次生理落果期，幼果内源多胺含量降到最低点；用3种外源多胺喷布花蕾，均延长了雌蕊寿命，增强了受精能力，提高了坐果率。     

柑橘开花前后子房(幼果)钙、硼营养与IAA、GA_(1/3)动态研究

对单性结实的国庆1号温州蜜柑和自花结实的华农本地早橘在开花前后子房(幼果)发育中钙、硼营养与内源IAA和GA1/3的浓度变化进行了测定。结果表明:1)在盛花期及花前阶段内国庆1号钙与硼浓度均居较高水平,盛花后即下降;而华农本地早盛花前相对较低,盛花后却有一上升过程;2)两品种的钙动态与各自的IAA动态呈显著正相关,国庆1号的硼与IAA亦呈显著正相关,但均与GA1/3无明显关系;3)国庆1号的钙浓度明显低于华农本地早。还就子房(幼果)中内源激素(IAA和GA1/3)与钙、硼营养的吸收及其生长发育的关系进行了讨论。     

花椰菜和小白菜种间杂种子房培养研究

以小白菜雄性不育系h08015为母本,以花椰菜自交系082005、082009、082010、082063为父本进行种间杂种离体子房培养。结果表明：离体培养时杂种子房发育天数、接种方式、激素水平及父本基因型对杂交种子发芽率均有明显影响。授粉后6 d的子房培养能获得较好的效果;4 d后剥取种子继续培养,获得的种子发芽率高于其他接种方式;不加激素的MS培养基好于添加6-BA及NAA的MS培养基;不同父本基因型最适取材时间不同,多数基因型最佳培养时间为授粉后6 d的子房,个别基因型则是授粉后10 d的子房。     

Differences in ovary size among olive (Olea europaea L.) cultivars are mainly related to cell number,not to cell size

Differences in mature fruit size among olive cultivars are related to differences in ovary size at bloom, but it is not known whether cell number or size determines the variation in ovary size. In this study we measured cell size and number in equatorial cross-sectional areas of the principal ovary tissues (mesocarp and endocarp) in eight cultivars with very different fruit and ovary size. The results showed that cell number explained most of the differences in ovary size, while cell size was not related to ovary size, except for a weak (R² = 0.33) correlation in the endocarp. Since sink strength is thought to be related to cell number, this finding supports the hypothesis that larger ovaries represent stronger sinks. The implications of greater sink strength with bigger ovaries are discussed. Within cultivars, while the cross-sectional areas of mesocarp and endocarp were similar, cell number was higher in the mesocarp but cell size was smaller compared to the endocarp.     

半滑舌鳎生物钟相关基因克隆及在卵巢发育成熟过程中表达特征分析

为阐明生物钟相关基因在半滑舌鳎(Cynoglossus semilaevis)卵巢成熟过程中的作用及机制,采集性成熟半滑舌鳎不同发育期的卵巢组织提取总RNA,通过反转录聚合酶链式反应(RT-PCR)技术对5个核心生物钟基因Clock1a、Bmal1a、Cry1a、Cry2和Per2的编码区(CDS)序列进行克隆和序列分析。结果显示,Clock1a的CDS序列编码712个氨基酸,序列中有功能性结构域PASD1和PAS11。Bmal1a的CDS序列编码626个氨基酸,序列中有功能性结构域PASD3和PAS11。Cry1a和Cry2的CDS序列分别编码631个、669个氨基酸,序列中均有功能性结构域FAD7。Per2的CDS序列编码1 415个氨基酸,序列中有功能性结构域PeriodC和PAS11。通过实时荧光定量PCR (qRT-PCR)分析5个生物钟基因mRNA在性成熟半滑舌鳎卵巢不同发育期的表达特性,发现5个生物钟基因存在性腺发育周年表达规律,且在卵巢Ⅱ期和Ⅲ期相对高表达(P<0.05),在卵巢Ⅳ、Ⅴ和Ⅵ期相对低表达,这说明生物钟基因对半滑舌鳎的卵巢发育成熟起到重要的调节作用。研究结果为进一步探究生物钟基因调控半滑舌鳎卵巢发育成熟的机制提供了重要参考,为提高半滑舌鳎的繁育效率提供了理论基础。     

家蚕化蛹第7天卵巢组织蛋白质标准图谱的构建

家蚕蛹期是卵子发育的重要时期,对蛹期卵巢的蛋白质组学研究将有助于认识家蚕的卵子发育过程。获取处于卵黄生成期的家蚕化蛹第7天卵巢组织,提取蛋白样品进行双向电泳,经银染后检测到682个蛋白点,这些蛋白点主要分布于分子质量15-90 kD、等电点4-8之间。对其中较高丰度的蛋白点进行飞行时间质谱(MALDI-TOF-MS)鉴定,共分析得到40个可信蛋白点,其中包括4个在家蚕中新鉴定的蛋白。经基因功能分类分析,这些蛋白包括营养储存蛋白、应激相关蛋白、蛋白翻译相关蛋白及代谢相关蛋白等。