Spermiogenesis and in Vitro Culture of Spermatogenic Cysts in Drosophila Pseudoobscura

Spennatogenesis is a complex process that involves differentiation and morphological changes of diploid stem cells into highly specialized, haploid, motile germ cells. Many of the transformative processes involved in mammalian spermatogenesis are conserved in flies, and their study would be facilitated by the availability of a reliable in vitro culture system. Culture of Drosophila melanogaster spermatogenic cysts is limited in usefulness because of early degeneration of cysts, low yield of elongated spermatozoa, and rare occurrences of motile sperm. We have developed a culture system for studying fly spermatogenesis using isolated spermatogenic cysts from the testes of Drosophila pseudoobscura. This species offers several advantages over D. melanogaster: (!) D. pseudoobscura testes can be easily distinguished in pupal stages due to intense red pigmentation, (2) survival of cysts to the elongated, motile form is easily achieved and highly repeatable, and (3) only minimal media is necessary in order to grow sperm to motility. Cysts containing primary spermatocytes isolated from late-stage pupa developed into motile sperm usually within five days of culture. Cysts underwent meiosis, elongation, individualization and coiling just as in D. melanogaster. To the best of our knowledge, this is the first report of Drosophila sperm cell culture where motility is consistently achieved. This culture system should prove valuable for spermatogenesis studies where cellular transformation processes must be manipulated in vitro

Spermiogenesis and in Vitro Culture of Spermatogenic Cysts in Drosophila Pseudoobscura

Spennatogenesis is a complex process that involves differentiation and morphological changes of diploid stem cells into highly specialized, haploid, motile germ cells. Many of the transformative processes involved in mammalian spermatogenesis are conserved in flies, and their study would be facilitated by the availability of a reliable in vitro culture system. Culture of Drosophila melanogaster spermatogenic cysts is limited in usefulness because of early degeneration of cysts, low yield of elongated spermatozoa, and rare occurrences of motile sperm. We have developed a culture system for studying fly spermatogenesis using isolated spermatogenic cysts from the testes of Drosophila pseudoobscura. This species offers several advantages over D. melanogaster: (!) D. pseudoobscura testes can be easily distinguished in pupal stages due to intense red pigmentation, (2) survival of cysts to the elongated, motile form is easily achieved and highly repeatable, and (3) only minimal media is necessary in order to grow sperm to motility. Cysts containing primary spermatocytes isolated from late-stage pupa developed into motile sperm usually within five days of culture. Cysts underwent meiosis, elongation, individualization and coiling just as in D. melanogaster. To the best of our knowledge, this is the first report of Drosophila sperm cell culture where motility is consistently achieved. This culture system should prove valuable for spermatogenesis studies where cellular transformation processes must be manipulated in vitro