title: Modification of sperm morphology during long-term sperm storage in the reproductive tract of the Chinese soft-shelled turtle, Pelodiscus sinensis.
abstract: Sperm storage in vivo extends the time window for fertilisation in several animal species, from a few days to several years. The underlying storage mechanisms, however, are largely unknown. In this study, spermatozoa from the epididymis and oviduct of Chinese soft-shelled turtles were investigated to identify potentially relevant morphological features and transformations at different stages of sperm storage. Large cytoplasmic droplets (CDs) containing lipid droplets (LDs) were attached to the midpiece of most spermatozoa in the epididymis, without migrating down the sperm tail. However, they were absent from the oviductal spermatozoa, suggesting that CDs with LDs may be a source of endogenous energy for epididymal spermatozoa. The onion-like mitochondria recovered their double-membrane morphology, with typical cristae, within the oviduct at a later stage of storage, thus implying that mitochondrial metabolism undergoes alterations during storage. Furthermore, a well developed fibrous sheath on the long principal piece was the integrating ultrastructure for glycolytic enzymes and substrates. These novel morphological characteristics may allow turtle spermatozoa to use diverse energy metabolism pathways at different stages of storage.
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Linli
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Xunguang
authors.initials: X
authors.lastname: Bian
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Shakeeb
authors.initials: S
authors.lastname: Ullah
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Yasir
authors.initials: Y
authors.lastname: Waqas
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Le
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Wang
authors.affiliation: Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
authors.forename: Qiusheng
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000818:Animals; D002681:China; D004822:Epididymis / Q000166:cytology; D005260:Female; D006801:Humans; D008297:Male; D010057:Oviducts / Q000166:cytology; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D013094:Spermatozoa / Q000166:cytology*; D014426:Turtles / Q000502:physiology*