Intersex in feral brown trout from Swiss midland rivers

The incidence of intersex in feral populations of brown trout Salmo trutta in Switzerland is reported. The affected brown trout showed spermatogenic activity in ovarian tissue.     

鸡胚公母性腺差异表达基因的基因芯片杂交筛选

采用Affymetrix公司鸡基因组芯片对9日龄鸡胚公母性腺总RNA进行了芯片杂交, 并对基因表达谱进行了分析。统计结果显示, 9日龄母鸡性腺表达基因数19 368个, 公鸡性腺表达基因数19 493个; 公母性腺绝对差异表达基因,即公鸡性腺表达而母鸡性腺不表达基因145个, 母鸡性腺表达而公鸡性腺不表达基因189个。绝对差异表达基因功能分类结果显示, 参与细胞组成、细胞加工和分子结合基因占多数, 部分基因参与细胞器组成、代谢加工、生物学调控以及催化反应和细胞信号转导等。值得注意的是, 本研究发现了一些已经报道同性别决定和分化有一定关联的基因, 如ASW、CHD1和SOX9等, 同时也发现了一些未知其同性腺分化和发育有关联的基因和编码假想蛋白的表达序列。进一步分析这些基因和表达序列的生物学功能和表达模式, 将对鸟类性别决定和分化机制的了解提供有益参考。     

A novel method for the generation of reaggregated organotypic cultures that permits juxtaposition of defined cell populations

Cellular reaggregation methods have been used to generate in vitro organotypic cultures as a means to elucidate the cellular and molecular requirements of organogenesis. However, reproducibility from experiment to experiment has remained problematic and furthermore, current protocols do not support reaggregation of many important tissues. Here, using the thymus as a model organ, we present a novel reaggregation method termed “compaction reaggregation” that offers improved kinetics of reaggregation and greatly improved efficiency. Using compaction reaggregation we have been able to reaggregate the aorta‐gonad‐ mesonephros region, a tissue that previously proved refractory to commonly used reaggregation methods, enabling the study of hematopoietic stem cell emergence and expansion. Additionally, compaction reaggregation permits the juxtaposition of different cell layers within the aggregated structure thus providing the means to study inductive interactions between different cell populations in vitro. genesis 47:346–351, 2009. © 2009 Wiley‐Liss, Inc.     

Rspo1对雌性脊椎动物性别分化的功能

长期以来雌性脊椎动物的性别分化被认为是一个“默认”的程序.但是近些年研究发现,Rspo1基因的突变或缺失可导致哺乳动物XX型个体性反转为雄性.Rspo1在鱼类、两栖爬行类、鸟类和哺乳类动物性腺发育的不同阶段表达,其表达在雌雄个体性别分化时期有差异,是潜在的性别调控基因.Rspo1在性别发育早期可通过Wnt/β-catenin信号通路调控性腺分化相关因子的表达,影响原始生殖细胞分裂增殖、细胞周期和生长发育,参与调控性腺中体细胞的分化.本文总结了近年来Rspo1在脊椎动物中的表达调控及其在雌性性别决定方面功能的研究进展.     

Reproductive biology of an odacine labrid, Odax pullus

The sexual ontogeny of butterfish Odax pullus was examined in the Hauraki Gulf of New Zealand through histological analysis of gonad material, size and age information and seasonal patterns of sexual maturation. The patterns of gonad development and schedules of male recruitment were established and sexual ontogeny of O. pullus was diagnosed as monandric protogyny, with all males developing from mature females after female-to-male sex reversal. All individuals underwent an immature female phase before maturing as functional females at 228·7-264·8 mm fork length (L(F) ) and at 1·1-1·5 years of age, and there was no evidence of a juvenile bisexual phase. Degenerating mature oogenic elements were found in the gonad lumen of individuals with developing spermatogenic tissue, providing histological evidence for functional protogyny. Sex change was estimated to occur at 359-379 mm L(F) and 2-3 years of age. The diagnosis of monandric protogyny for O. pullus coincided with the pattern of sexual ontogeny seen in the majority of labrids, particularly those of the same clade (tribe Hypsigenyini) and contrasted with that seen in a number of other temperate labrids. This study suggests that the protogynous mode of sexual development in O. pullus is likely to be lineage-specific, i.e. associated with the phylogeny of labrid sexual development, and is not constrained by environmental effects on the evolution of sex change in temperate regions.     

Patterns of structural change in gonads of the divine dwarfgoby Eviota epiphanes as they sexually transition

This study documents changes in gonadal structure for the serial hermaphrodite (or bidirectional sex changer) divine dwarfgoby Eviota epiphanes (family Gobiidae) as individuals transition in both directions. To evaluate transitional gonad morphology, individuals actively producing the same gamete type (oocytes or sperm) were set up into pairs and euthanised over a period of 14 days to get a time series of morphological changes during gonad transformation. Results from this study show that rapid changes in the gonad take place at a structural level as individuals change their reproductive function and gamete production. Changing from oocyte production (o-phase) to sperm production (s-phase) starts with the breakdown of vitellogenic oocytes (i.e., atresia) followed by the appearance and proliferation of spermatogenic tissue which, in most cases, was not previously visible. Changing from sperm production to oocyte production included the cessation of sperm production, a reduction in size and number of seminiferous lobules and the maturation of previtellogenic oocytes already present in the gonads. Experimental fish changed from oocyte production to sperm production more readily than from sperm production to oocyte production. The hypothesis that shifts in sexual function among serially hermaphroditic fish species have a similar cost in either direction is not supported in E. epiphanes.     

Seasonal changes in energy and the energy cost of spawning in Gulf of Alaska Pacific cod

In the Gulf of Alaska, adult Pacific cod exhibited an annual cycle of condition, gonad index and liver index in which maximum values occurred in ripe fish in March and minima in July. About 30–31 % of prespawning stored energy was expended during the spawning effort. The energy associated with spawning derived from liver (24% and 18%), somatic tissue (22% and 33%) and gonad (53% and 48%) for females and males, respectively. Liver index and gonad index at the time of sampling were directly related in females, but in males gonad index was best related to liver index 1–3 months earlier.
The Pacific cod is very similar to the Atlantic cod in terms of energy cycling, maximum gonad sizes, energy expended during spawning and gonadal contribution to energy expenditure. However, in Pacific cod, somatic tissue contributes markedly to energy expended during reproduction. The Pacific cod cod differs from the walleye pollock with respect to gonad index (13% and 20%ν. 20% and 8% for females and males, respectively), spawning weight loss (25%ν. 38%), liver energy loss during spawning (71%ν. 55%) and energy cost of spawning.