Gonads in Histiostoma mites (Acariformes: Astigmata): Structure and development
The development of male and female gonads in arrhenotokous and thelytokous species of Histiostoma was studied using transmission electron microscopy (TEM). All instars were examined: larvae, protonymphs, facultative heteromorphic deutonymphs (=hypopi), tritonymphs, and adults. In testis primordium,...
| Veröffentlicht in: | Ventricular Restraint Improves Outcomes in HF Patients with CRT. - 2011. - Amsterdam [u.a.] |
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| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
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2014transfer abstract
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| Zugriff auf das übergeordnete Werk: | Ventricular Restraint Improves Outcomes in HF Patients with CRT |
| Schlagworte: | Testis Ovary Intercellular bridges “Acari” Germinal cells Histiostomatidae Gonadal development Testicular central cell Ovarian nutritive cell |
| Umfang: | 17 |
| Zusammenfassung: | The development of male and female gonads in arrhenotokous and thelytokous species of Histiostoma was studied using transmission electron microscopy (TEM). All instars were examined: larvae, protonymphs, facultative heteromorphic deutonymphs (=hypopi), tritonymphs, and adults. In testis primordium, spermatogonia surrounding a testicular central cell (TCC) with a gradually enlarging, branched nucleus are present already at the larval stage. Spermatogonia and the TCC are connected via narrow, tubular intercellular bridges revealing that the TCC is a germline cell. Spermatocytes appear at the protonymphal stage. At the heteromorphic deutonymph stage, the testis primordium is similar to that of the protonymph, but in the tritonymph it is much larger and composed as in the adult: spermatids as well as sperm cells are present. The latter are congregated ventrally in the testis at the entrance of the deferent duct. The development of male and female gonads in arrhenotokous and thelytokous species of Histiostoma was studied using transmission electron microscopy (TEM). All instars were examined: larvae, protonymphs, facultative heteromorphic deutonymphs (=hypopi), tritonymphs, and adults. In testis primordium, spermatogonia surrounding a testicular central cell (TCC) with a gradually enlarging, branched nucleus are present already at the larval stage. Spermatogonia and the TCC are connected via narrow, tubular intercellular bridges revealing that the TCC is a germline cell. Spermatocytes appear at the protonymphal stage. At the heteromorphic deutonymph stage, the testis primordium is similar to that of the protonymph, but in the tritonymph it is much larger and composed as in the adult: spermatids as well as sperm cells are present. The latter are congregated ventrally in the testis at the entrance of the deferent duct. |
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| Beschreibung: | 17 |
| DOI: | 10.1016/j.asd.2014.04.006 |