Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, ...Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, embryos, and tadpoles of Duttaphrynus melanostictus and Pelophylax nigromaculatus in south China. Our results suggested that the survival of eggs and embryos remaining in the egg capsules of P. nigromaculatus and D. melanostictus was significantly higher than those removed from the egg capsule at 12-h intervals within 72 h in the presence of G. affinis. The survival of P. nigromaculatus eggs and embryos without egg capsules was significantly lower than those of D. melanostictus without egg capsules. The survival of P. nigromaculatus eggs and embryos with egg capsules was significantly higher than those of D. melanostictus with egg capsules from 24 h to 72 h except for 12 h. The survival of D. melanostictus tadpoles was significantly higher than that of P. nigromaculatus tadpoles in the presence of G. affinis. The survival of Gosner stage 26 tadpoles of P. nigromaculatus was significantly higher than that of Gosner stage 30 tadpoles from 12 h to 60 h, but there were no significant differences at 72 h. In contrast, the survival of Gosner stage 26 tadpoles of D. melanostictus was significantly lower than that of Gosner stage 30 tadpoles within 72 h, recording every 12 h. The increasing temperature caused a significant increase in predation by G. affinis on P. nigromaculatus eggs and embryos. The outer jelly capsule surrounding anurans eggs might serve as a mechanical defense against predation by G. affinis due to its large diameter, relatively stationary state and unpalatability. The differences in the vulnerability of P. nigromaculatus and D. melanostictus embryos and tadpoles to G. affinis probably due to differences in the unpalatability, black skin and activity. Based on the magnitude of predation by G. affinis on the eggs, embryos and tadpoles of these two species and the combined impact of temperature, we might speculate that invasive G. affinis and global warming would have more detrimental impacts on population viability of P. nigromaculatus than D. melanostictus in China.展开更多
The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan, South China are described and illustra...The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan, South China are described and illustrated in detail for the first time. A new species Markuelia elegans sp. nov. is established based mainly on embryos from the Upper Cambrian. A few of animal＇s resting eggs, which are comparable with those of the Ediacaran Doushantuo Formation, have been also found in the Upper Cambrian of western Hunan. The membrane of one egg from the uppermost Cambrian has been replaced by pyrite and the overgrowth of the pyrite crystals exhibits a unique inorganic pattern termed herein ＇Pseudoembryo＇. The taphonomic setting in deeper water with possible strong reducing conditions promoted the excellent preservation for the Markuelia specimens. The study of Markuelia provides not only constraint on the anatomy, affinity, embryonic development and phylogenetic significance of this wormlike animal and but also opens a new window onto the evolution and development of the earliest animals.展开更多
In crab,embryogenesis is a complicated developmental program marked by a series of critical events.RNA-Sequencing technology offers developmental biologists a way to identify many more developmental genes than ever be...In crab,embryogenesis is a complicated developmental program marked by a series of critical events.RNA-Sequencing technology offers developmental biologists a way to identify many more developmental genes than ever before.Here,we present a comprehensive analysis of the transcriptomes of Eriocheir sinensis oosperms(Os) and embryos at the 2-4 cell stage(Cs),which are separated by a cleavage event.A total of 18 923 unigenes were identified,and 403 genes matched with gene ontology(GO)terms related to developmental processes.In total,432 differentially expressed genes(DEGs) were detected between the two stages.Nine DEGs were specifically expressed at only one stage.These DEGs may be relevant to stage-specific molecular events during development.A number of DEGs related to 'hedgehog signaling pathway','Wnt signaling pathway' 'germplasm','nervous system','sensory perception' and'segment polarity' were identified as being up-regulated at the Cs stage.The results suggest that these embryonic developmental events begin before the early cleavage event in crabs,and that many of the genes expressed in the two transcriptomes might be maternal genes.Our study provides ample information for further research on the molecular mechanisms underlying crab development.展开更多
基金funded by grants from the National Natural Science Foundation of China(31270443,31500329)the Science Foundation of Zhejiang Provincial Committee of Education(Y201534237)the Scientific Research Foundation of Ph.D.,Lishui University(QD1423)
文摘Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, embryos, and tadpoles of Duttaphrynus melanostictus and Pelophylax nigromaculatus in south China. Our results suggested that the survival of eggs and embryos remaining in the egg capsules of P. nigromaculatus and D. melanostictus was significantly higher than those removed from the egg capsule at 12-h intervals within 72 h in the presence of G. affinis. The survival of P. nigromaculatus eggs and embryos without egg capsules was significantly lower than those of D. melanostictus without egg capsules. The survival of P. nigromaculatus eggs and embryos with egg capsules was significantly higher than those of D. melanostictus with egg capsules from 24 h to 72 h except for 12 h. The survival of D. melanostictus tadpoles was significantly higher than that of P. nigromaculatus tadpoles in the presence of G. affinis. The survival of Gosner stage 26 tadpoles of P. nigromaculatus was significantly higher than that of Gosner stage 30 tadpoles from 12 h to 60 h, but there were no significant differences at 72 h. In contrast, the survival of Gosner stage 26 tadpoles of D. melanostictus was significantly lower than that of Gosner stage 30 tadpoles within 72 h, recording every 12 h. The increasing temperature caused a significant increase in predation by G. affinis on P. nigromaculatus eggs and embryos. The outer jelly capsule surrounding anurans eggs might serve as a mechanical defense against predation by G. affinis due to its large diameter, relatively stationary state and unpalatability. The differences in the vulnerability of P. nigromaculatus and D. melanostictus embryos and tadpoles to G. affinis probably due to differences in the unpalatability, black skin and activity. Based on the magnitude of predation by G. affinis on the eggs, embryos and tadpoles of these two species and the combined impact of temperature, we might speculate that invasive G. affinis and global warming would have more detrimental impacts on population viability of P. nigromaculatus than D. melanostictus in China.
基金supported by the NationalNatural Science Foundation of China(Grant Nos.40772008 and 40572003)the Research Fund for DoctoralProgram of High Education(Grant No.20060001059)State Key Laboratory of Paleobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,ChineseAcademy of Sciences(Grant No.083101)
文摘The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan, South China are described and illustrated in detail for the first time. A new species Markuelia elegans sp. nov. is established based mainly on embryos from the Upper Cambrian. A few of animal＇s resting eggs, which are comparable with those of the Ediacaran Doushantuo Formation, have been also found in the Upper Cambrian of western Hunan. The membrane of one egg from the uppermost Cambrian has been replaced by pyrite and the overgrowth of the pyrite crystals exhibits a unique inorganic pattern termed herein ＇Pseudoembryo＇. The taphonomic setting in deeper water with possible strong reducing conditions promoted the excellent preservation for the Markuelia specimens. The study of Markuelia provides not only constraint on the anatomy, affinity, embryonic development and phylogenetic significance of this wormlike animal and but also opens a new window onto the evolution and development of the earliest animals.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A409)the Scientific and Technological Innovation Project of Qingdao National Laboratory for Marine Science and Technology(No.2015ASKJ02)the National Natural Science Foundation of China(Nos.41276165 to Dr.CUI Zhaoxia,31302187 to Dr.HUI Min)
文摘In crab,embryogenesis is a complicated developmental program marked by a series of critical events.RNA-Sequencing technology offers developmental biologists a way to identify many more developmental genes than ever before.Here,we present a comprehensive analysis of the transcriptomes of Eriocheir sinensis oosperms(Os) and embryos at the 2-4 cell stage(Cs),which are separated by a cleavage event.A total of 18 923 unigenes were identified,and 403 genes matched with gene ontology(GO)terms related to developmental processes.In total,432 differentially expressed genes(DEGs) were detected between the two stages.Nine DEGs were specifically expressed at only one stage.These DEGs may be relevant to stage-specific molecular events during development.A number of DEGs related to 'hedgehog signaling pathway','Wnt signaling pathway' 'germplasm','nervous system','sensory perception' and'segment polarity' were identified as being up-regulated at the Cs stage.The results suggest that these embryonic developmental events begin before the early cleavage event in crabs,and that many of the genes expressed in the two transcriptomes might be maternal genes.Our study provides ample information for further research on the molecular mechanisms underlying crab development.
