Ultrastructure of spermatogenic cells and spermatozoa in Hoplias malabaricus (Teleostei, Characiformes, Erythrinidae)

Abstract

The differentiation of spermatids in Hoplias malabaricus is characterized by chromatin compaction, flagellum development, nuclear rotation, nuclear fossa formation, and excess cytoplasm elimination. In the resulting spermatozoon, the head is round and the nucleus contains chromatin compacted in thick filaments, peripherically arranged, to a central electron-lucent area. The acrosome is absent. The nuclear fossa is eccentric but not pronounced. The proximal centriole penetrates it and is oblique to the flagellum. The long midpiece has several converging elongate vesicles, forming membranous hoops in the initial segment of the flagellum, but has no cytoplasmic channel. The mitochondria are elongate and branched or C-shaped and located around the initial segment of the axoneme. The lateral flagellum does not show lateral projections. The ultrastructural characteristics of H. malabaricus spermatozoa are similar to the Cypriniformes. 2001 The Fisheries Society of the British Isles

Comparative folliculogenesis and spermatogenesis of four teleost fish from a Reservoir in south‐eastern Brazil

“…During the spermatogenesis of the four studied species, a reduction of 80–90% of the nuclear diameter of the spermatogenic cells was registered, similar to those reported by Sprando and Russel (1988). The reduction of the nuclear volume during the differentiation from spermatid to spermatozoa is due to chromatin compaction (Quagio‐Grassiotto et al. 2001).…”

Semicystic spermatogenesis and biflagellate spermatozoon ultrastructure in the Nile electric catfish Malapterurus electricus (Teleostei: Siluriformes: Malapteruridae)

“…1993), in poeciliid and zenarchopterid species (Jamieson and Grier 1993), in the diplomystid Diplomystes mesembrinus (Quagio‐Grassiotto et al . 2001b), the erythrinid Hoplias malabaricus (Quagio‐Grassiotto et al . 2001a), in curimatid species (Quagio‐Grassiotto et al .…”

“…1998; Andrade et al . 2001; Quagio‐Grassiotto et al . 2001a, 2003) but if rotation is complete (90°), the nuclear fossa is medial and the flagellum is medial and perpendicular to the nucleus (Mattei et al .…”

“…For example, the proximal centriole is either antero‐lateral and slightly oblique to the basal body (Jamieson 1991), lateral, oblique and distant from the distal centriole (Mattei et al . 1995), anterior, coaxial and slightly oblique to the basal body (Quagio‐Grassiotto et al . 2001a), anterior, lateral and perpendicular to the basal body (Matos et al .…”

Sperm and spermatozeugma ultrastructure in the inseminating speciesTyttocharax cochui,T. tambopatensis, andScopaeocharax rhinodus (Pisces: Teleostei: Characidae: Glandulocaudinae: Xenurobryconini)

“…Jamieson (1991) provided the first TEM of an aquasperm of a species of Characiformes, Paracheirodon innesi of the family Characidae. Since that time, ultrastructural de- scriptions of characiform aquasperm have been published for the following families: Characidae (Matos et al, 1993(Matos et al, , 2000Burns et al, 1998;Romagosa et al, 1999), Citharinidae (Mattei et al, 1995), Curi- matidae (Medina et al, 1994;Matos et al, 1998;Quagio-Grassiotto et al, 2003), Anostomidae (Pecio, 2003), and Erythrinidae (Quagio-Grassiotto et al, 2001). One notable character of all these aquasperm is the spherical shape of the nucleus.…”