Goldsinny wrasse (Ctenolabrus rupestris) is an extreme vtgAa-type pelagophil teleost

During oocyte maturation in the goldsinny wrasse (Ctenolabrus rupestris) extensive proteolysis of yolk proteins generates a large pool of free amino acids that drive hydration of the pelagic egg. By cloning hepatic vitellogenins (vtg) and using mass spectrometry, N-terminal microsequencing, and Western-immunoblotting to identify the yolk proteins (Yp), we show that multiple forms of vitellogenin mRNAs (vtgAa, vtgAb, and vtgC) are expressed in the liver, but only a single major class of the Yps derived from vtgAa predominates in the oocytes. Some Yps derived from vtgAb and vtgC appear also to be incorporated in the oocytes and eggs, but only at background levels. During oocyte hydration the vtgAa-derived lipovitellin heavy chain (LvH-Aa) and its cleavage variants are completely degraded leaving only a processed lipovitellin light chain (LvL-Aa) fragment as the major yolk protein for embryonic development. The maturational cleavage site of the LvL-Aa is identified as two amino acids downstream from the conserved Tyr(1168) of VtgAa in Atlantic halibut. In addition, although a beta'-component (approximately 18 kDa) is present in the oocytes, it is not fully degraded during the hydration process.     

枝角类休眠卵形成和萌发的研究进展

综述了多年来国内外对枝角类休眠卵的研究概况,重点介绍了休眠卵的形态、形成的条件、保存方式及萌发条件等.休眠卵通常呈圆形或椭圆形,外被一层厚的卵膜.休眠卵的形成主要依赖于生物因子(遗传因素、种群密度等)和非生物因子(温度、食物、光照等)的作用.影响休眠卵萌发的因子有休眠卵的保存方式、保存时间、萌发阶段的光照及温度等.     

Inositol 1,4,5-trisphosphate receptor 1, a widespread Ca2+ channel, is a novel substrate of polo-like kinase 1 in eggs

To initiate embryo development, the sperm induces in the egg release of intracellular calcium ([Ca²⁺]_i). During oocyte maturation, the inositol 1,4,5-trisphosphate receptor (IP₃R1), the channel implicated, undergoes modifications that enhance its function. We found that IP₃R1 becomes phosphorylated during maturation at an MPM-2 epitope and that this persists until the fertilization-associated [Ca²⁺]_i responses cease. We also reported that maturation without ERK activity diminishes IP₃R1 MPM-2 reactivity and [Ca²⁺]_i responses. Here, we show that IP₃R1 is a novel target for Polo-like kinase1 (Plk1), a conserved M-phase kinase, which phosphorylates it at an MPM-2 epitope. Plk1 and IP₃R1 interact in an M-phase preferential manner, and they exhibit close co-localization in the spindle/spindle poles area. This co-localization is reduced in the absence of ERK activity, as the ERK pathway regulates spindle organization and IP₃R1 cortical re-distribution. We propose that IP₃R1 phosphorylation by Plk1, and possibly by other M-phase kinases, underlies the delivery of spatially and temporally regulated [Ca²⁺]_i signals during meiosis/mitosis and cytokinesis.     

沙棘木蠹蛾卵和幼虫空间分布的地统计学分析

沙棘木蠹蛾(H olcocerushippophaecolus Hua,Chou ,Fang et Chen)是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫,其危害发生在幼虫期,主要危害沙棘(H ippophae rhamnoidea)的根干部。为了有效地控制其危害,深入了解种群的空间结构,利用地统计学方法分析了两种受害程度不同的林分内沙棘木蠹蛾幼虫种群和重度受害林分内卵块的空间分布特性。结果表明:两种受害程度不同的林分内,沙棘木蠹蛾的危害具有显著差异,轻度受害林分内无虫样本所占的比例较大,达70 % ,而重度受害林分内不到2 0 % ;虫口密度在轻度受害林分内超过6头/株的只有6 .9% ,而重度受害林分内高达31.9%。根据全方向的变异函数曲线图分析得知:重度受害林分和轻度受害林分内幼虫种群的空间依赖范围分别为7.3m和87.4 18m,而局部空间连续性强度分别为0 .914和0 .178。重度受害林分内幼虫表现较强的空间聚集性,而轻度受害林分则表现为随机分布。在重度受害林分中,单株沙棘树上沙棘木蠹蛾卵块数量最多的为11个,最少的为1个,有卵株率达72 %。分别采用四种不同的理论模型来拟合卵块的实际变异曲线图,得知其全方向的变异函数曲线为指数型,空间依赖范围大小为3.6 m,局部空间连续性强度为0 .876 ,卵块在重度受害林分中呈现较强     

中华绒螯蟹受精卵、流产卵氨基酸及脂肪酸组成的比较研究

采用气相色谱仪和氨基酸分析仪测定中华绒螯蟹不同种群 (太湖种群和温州种群 )受精卵和温州种群流产卵脂肪酸及氨基酸的组成。结果表明 ,中华绒螯蟹太湖种群受精卵、温州种群受精卵和温州种群流产卵在必需氨基酸和半必需氨基酸的含量上无显著差异 ,而谷氨酸 (Glu)、胱氨酸 (Cys)和丝氨酸 (Ser)三种非必需氨基酸的含量差异显著。太湖种群受精卵、温州种群受精卵及温州种群流产卵的脂肪酸种类分别为 16、13和 14种。饱和脂肪酸(SFA)占脂肪酸总量的 18 96 %— 2 3 0 9% ,单烯酸 (MUFA)占 5 1 76 %— 6 2 6 5 % ,多不饱和脂肪酸 (PUFA)占14 2 7%— 2 8 96 % ,其中最主要的脂肪酸为C16∶0、C16∶1和C18∶1。除C2 0∶1外 ,其他脂肪酸含量在三者之间都有显著差异。太湖种群受精卵的C18∶2、C18∶3显著高于温州种群受精卵 ,而温州种群流产卵的DHA要显著高于太湖种群受精卵。温州种群受精卵和流产卵在C16以下的脂肪酸 ,其含量均无显著差异。此外 ,本文还讨论了脂肪酸及氨基酸含量与流产的关系及脂肪酸组成对出苗率的影响。     

Females from resting eggs and parthenogenetic eggs in the rotifer Brachionus calyciflorus: lipid droplets, starvation resistance and reproduction

1. In the heterogonic life cycle of monogonont rotifers, amictic (female‐producing) females develop from two types of eggs: fertilised resting (diapausing) eggs and parthenogenetic subitaneous eggs. Females hatched from resting eggs initiate clonal populations by female parthenogenesis and are called stem females. This study compares females from resting and parthenogenetic eggs that were produced under identical culture conditions and were of similar birth order. 2. Newborn stem females had many more lipid droplets in their tissues than similar‐sized, newborn females from parthenogenetic eggs. When neonates were stained with Nile Red and viewed under epifluorescent illumination, these droplets were shown to be sites of neutral‐lipid storage products. 3. Stem females had no posterolateral spines and short anterior spines, while their mothers and offspring in subsequent, parthenogenetic generations typically had long posterolateral spines and elongated anterior spines. 4. Newborn stem females survived starvation significantly longer than newborn females from parthenogenetic eggs. 5. When females from resting and parthenogenetic eggs were cultured from birth to death at a high food concentration, the reproductive potential (r day^?1) of the stem females was significantly higher (0.82–0.88 versus 0.70), primarily because of egg production at an earlier age. The mean lifetime fecundity (R_o) of stem females was significantly greater than that of females from parthenogenetic eggs. 6. Extensive lipid reserves should increase the ability of stem females to colonise new habitats. Firstly, compared with females from parthenogenetic eggs, stem females are more likely to experience starvation or food limitation. Resting eggs hatch in response to physical and chemical factors that are not directly related to food availability, and from sediments that may be far from food‐rich surface waters. Secondly, when food is abundant, stem females have a greater reproductive potential.     

Age, distribution and abundance of viable resting eggs of Acartia pacifica (Copepoda: Calanoida) in Xiamen Bay, China

The distribution and abundance of viable resting eggs of copepod Acartia pacifica in Xiamen Bay, China, were determined in the laboratory by the presence of nauplii hatched from the sediments. Sediment cores to a depth of 30 cm, sliced at 1.0 cm intervals, showed that most viable resting eggs of A. pacifica occurred near the sediment surface (0-5 cm), and the number of viable eggs sharply decreased with depth of the sediment, although resting eggs remained viable as deep as 23 cm. ²¹⁰Pb analyses of the sediments indicated that the maximum age of viable eggs of A. pacifica was 20.5 years and the mean egg age was 4.3 years. The egg mortality of A. pacifica in the sediment was 0.1408 year⁻¹, or 85.92% annual egg survival, calculated by regressing ln(egg density) on the age of the sediment. The horizontal distribution of viable resting eggs ranged from 2.27×10³ to 3.85×10⁵ m⁻², with a mean value of 9.49×10⁴ m⁻². Regressions between viable eggs of A. pacifica and all fine-fraction particle size classes (at 2 μm intervals) were not significant. The accumulation of viable resting eggs that can persist for an extended period of time provided evidence for the existence of an egg bank of A. pacifica in the seabed of Xiamen Bay.     

Reproductive isolation among geographically and temporally isolated marine Brachionus strains

Using a polyclonal antibody against the mate recognition pheromone (MRP) of Brachionus rotundiformis Koshiki strain, we investigated the behavioral reproductive isolation and the similarity of MRP among geographically and temporally isolated B. rotundiformis strains. Males of the Koshiki strain did not discriminate in mating attempts among females of the Koshiki strain and those of conspecific allopatric strains from Hamana, Fiji, Thailand and Spain. Likewise, Koshiki males attempted mating with statistically indistinguishable frequency with Koshiki females and B. plicatilis strains. However, copulation was not consummated between Koshiki males and B. plicatilis females. The amount of anti-MRP binding to three allopatric B. rotundiformis strains was similar to that of the Koshiki strain, but binding to Hamana and the B. plicatilis strain was significantly lower. Four temporally separated B. rotundiformis populations were hatched from resting eggs collected from 0, 5, 10 and 15 cm depth in the sediment of Kai-ike pond in Koshiki island, Japan. Sediment age was determined using the ²¹⁰Pb method, allowing us to estimate that resting eggs from 15 cm depth were produced 65 years ago. Results of mating assays and anti-MRP binding showed that no behavioral reproductive isolation exists among the four temporally isolated Koshiki strains. B. rotundiformis appears to be reproductively isolated from B. plicatilis, but heterospecific matings are still attempted between B. plicatilis and B. rotundiformis, suggesting that the MRP remains sufficiently similar to elicit circling behavior.     

Spine development in Brachionus quadridentatus from an Australian billabong: genetic variation and induction by Asplanchna

Fertilized resting eggs of Australian Brachionus quadridentatus hatched 2–3 days after hydration into females with or, more frequently, without posterior lateral spines. These females then produced clones with short-spined or long-spined phenotypes. Asplanchna girodi induced females from two short-spined clones and one long-spined clone to produce daughters with significantly longer posterior lateral spines. In all clones, there were significant differences in spine development among offspring of mothers within Asplanchna and control treatments. The range of phenotypes reported in one short-spined clone is observed in the billabong and includes much of the variation described for the species, with mehleni (long-spined) phenotypes occurring with Asplanchna. In B. quadridentatus, the ecological significance of long-spined, basic phenotypes, and of the spine-development response to Asplanchna, is unclear. In laboratory cultures, females of all clones were attached to the substratum or water surface, and were safe from Asplanchna; in nature, females are epiphytic and probably rarely susceptible to Asplanchna. Most (96%) resting eggs produced in cultures and kept under culture conditions hatched after a 7-day latent period. This raises questions regarding natural conditions which might prevent hatching and allow accumulation of resting eggs in a sediment egg bank. Hatching of resting eggs in nature may be enhanced in sediments which dry and then become flooded after rains.     

新疆石河子棉蚜越冬卵的发育规律

棉蚜雌性蚜交配个体平均产卵量为 6 3± 1 1粒 ;未交配个体也产卵 ,卵亦变色 ,但卵量极少。越冬卵经 5 %NaOH浸泡 2 4h后卵壳透明 ,镜下观察可见受精卵胚胎发育到体躯分节期开始越冬。冬后胚胎发育仅处在颗粒团状的饱满卵应为无效卵 ,不会孵化 ;颜色发亮的卵处理后胚胎外貌清晰可见 ,此种卵当天即可破壳。棉蚜卵为滞育卵 ,春季降水对孵化有促进作用 ;室外棉蚜卵的饱满率和饱满卵的孵化率较低。该地区秋冬气候特点可能是石河子地区棉蚜卵低温条件下安全越冬的重要因素