The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, espe- cially the hormone-related differences in maturing male fish has seldom been documented. In this ...The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, espe- cially the hormone-related differences in maturing male fish has seldom been documented. In this study, a full length cDNA sequence of the vasa gene was cloned from Japanese sea bass, Lateolabraxjaponicas, and it was namedjsb-vasa. Homology analysis showed thatjsb-vasa was closely related to its teleost homologs. The spatial distribution ofjsb-vasa indicated that it was only highly ex- pressed in testis, showing its germ cell-specific expression pattern. During the testicular development cycle, jsb-vasa was highly expressed during early period of spermatogenesis, and reduced when spermatogenesis advanced. In addition, the jsb-vasa gene ex- pression was significantly inhibited at 6 h, 12 h and 24 h after injecting hCG （human ehorionic gonadotropin） and GnRHa （Gonad- otropin-releasing hormone analogue）, indicating thatjsb-vasa gene may play an important role in spermatogenesis of Japanese sea bass, and be under the regulation of external sex hormones.展开更多
Aims Anthropogenic climate change is predicted to increase mean temperatures and rainfall seasonality.How tropical rainforest species will respond to this climate change remains uncertain.Here,we analysed the effects ...Aims Anthropogenic climate change is predicted to increase mean temperatures and rainfall seasonality.How tropical rainforest species will respond to this climate change remains uncertain.Here,we analysed the effects of a 4-year experimental throughfall exclusion(TFE)on an Australian endemic palm(Normambya normanbyi)in the Daintree rainforest of North Queensland,Australia.We aimed to understand the impact of a simulated reduction in rainfall on the species’physiological processes and fruiting phenology.Methods We examined the fruiting phenology and ecophysiology of this locally abundant palm to determine the ecological responses of the species to drought.Soil water availability was reduced overall by~30%under a TFE experiment,established in May 2015.We monitored monthly fruiting activity for 8 years in total(2009–2018),including 4 years prior to the onset of the TFE.In the most recent year of the study,we measured physiological parameters including photosynthetic rate,stomatal conductance and carbon stable isotopes(δ13C,an integrated measure of water use efficiency)from young and mature leaves in both the dry and wet seasons.Important Findings We determined that the monthly fruiting activity of all palms was primarily driven by photoperiod,mean solar radiation and mean temperature.However,individuals exposed to lower soil moisture in the TFE decreased significantly in fruiting activity,photosynthetic rate and stomatal conductance.We found that these measures of physiological performance were affected by the TFE,season and the interaction of the two.Recovery of fruiting activity in the TFE palms was observed in 2018,when there was an increase in shallow soil moisture compared with previous years in the treatment.Our findings suggest that palms,such as the N.normanbyi,will be sensitive to future climate change with long-term monitoring recommended to determine population-scale impacts.展开更多
基金supported by the National Key Technologies R&D Program of China(2011BAD13B03)
文摘The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, espe- cially the hormone-related differences in maturing male fish has seldom been documented. In this study, a full length cDNA sequence of the vasa gene was cloned from Japanese sea bass, Lateolabraxjaponicas, and it was namedjsb-vasa. Homology analysis showed thatjsb-vasa was closely related to its teleost homologs. The spatial distribution ofjsb-vasa indicated that it was only highly ex- pressed in testis, showing its germ cell-specific expression pattern. During the testicular development cycle, jsb-vasa was highly expressed during early period of spermatogenesis, and reduced when spermatogenesis advanced. In addition, the jsb-vasa gene ex- pression was significantly inhibited at 6 h, 12 h and 24 h after injecting hCG （human ehorionic gonadotropin） and GnRHa （Gonad- otropin-releasing hormone analogue）, indicating thatjsb-vasa gene may play an important role in spermatogenesis of Japanese sea bass, and be under the regulation of external sex hormones.
基金supported by grants from the Skyrail Rainforest Foundation(http://www.skyrailfoundation.org/)Wet Tropics Management Authority(https://www.wettropics.gov.au)to N.V.,and Australian Research Council grants(FT130101319,DP130104092)to S.L.
文摘Aims Anthropogenic climate change is predicted to increase mean temperatures and rainfall seasonality.How tropical rainforest species will respond to this climate change remains uncertain.Here,we analysed the effects of a 4-year experimental throughfall exclusion(TFE)on an Australian endemic palm(Normambya normanbyi)in the Daintree rainforest of North Queensland,Australia.We aimed to understand the impact of a simulated reduction in rainfall on the species’physiological processes and fruiting phenology.Methods We examined the fruiting phenology and ecophysiology of this locally abundant palm to determine the ecological responses of the species to drought.Soil water availability was reduced overall by~30%under a TFE experiment,established in May 2015.We monitored monthly fruiting activity for 8 years in total(2009–2018),including 4 years prior to the onset of the TFE.In the most recent year of the study,we measured physiological parameters including photosynthetic rate,stomatal conductance and carbon stable isotopes(δ13C,an integrated measure of water use efficiency)from young and mature leaves in both the dry and wet seasons.Important Findings We determined that the monthly fruiting activity of all palms was primarily driven by photoperiod,mean solar radiation and mean temperature.However,individuals exposed to lower soil moisture in the TFE decreased significantly in fruiting activity,photosynthetic rate and stomatal conductance.We found that these measures of physiological performance were affected by the TFE,season and the interaction of the two.Recovery of fruiting activity in the TFE palms was observed in 2018,when there was an increase in shallow soil moisture compared with previous years in the treatment.Our findings suggest that palms,such as the N.normanbyi,will be sensitive to future climate change with long-term monitoring recommended to determine population-scale impacts.
