The cytoskeletal proteins in the contractile tissues of the testis and its excurrent ducts of the passerine bird, Masked Weaver (Ploceus velatus)

摘要

The cellular composition of the testicular capsule, seminiferous peritubular tissue, the epithelia as wellas periductal muscle cell layers of the excurrent ducts was studied, in sexually mature and active MaskedWeaver (Ploceus velatus) birds of the passerine family, Ploceidae. Ultrastructure of the contractile cellsin the testicular capsule, peritubular and periductal tissues showed that these cells were smooth musclesof typical morphological characteristics. Variability in the immunohistochemical co-expression ofmicrofilaments and intermediate filaments in the different tissues was evident. Actin and desmin proteinswere co-expressed immunohistochemically in the testicular capsule and seminiferous peritubularsmooth muscle layer. Actin was singly and very weakly expressed in the rete testis epithelium whilecytokeratins and desmin were co-expressed in the epithelium of the excurrent ducts. The periductalmuscle layer of all ducts of the epididymis, the ductus deferens as well as the seminal glomus, stronglyco-expressed actin and desmin. Vimentin was absent in all cells and tissue types studied. There is clearevidence that the tissues of the male gonad and its excurrent ducts in the Masked Weaver, as has beenreported for members of the Galloanserae and Ratitae, contain well-formed contractile tissues whosefunction would include the transportation of luminal through-flow from the testis into, and through, itsexcurrent ducts. The microtubule helix in the head and of the mid-piece, of elongating spermatids, aswell as of the mature spermatozoa in the various excurrent ducts, including some spermatozoa in theseminal glomus, also co-expressed these three proteins.