Acrosome reaction in spermatozoa of the hagfish <i>Eptatretus burgeri</i> (Agnatha)

Morisawa, Sachiko

doi:10.1046/j.1440-169x.1999.00411.x

Cited by 17 publications

(17 citation statements)

References 14 publications

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“…A nuclear peg has not been reported in other bivalves, or even in other molluscs, although some species of the gastropod Patella show a narrowing of the nucleus which sits within the acrosomal invagination (Hodgson & Bernard 1988;Hodgson et al 1996). A similar structure to the nuclear peg has been noted in the spermatozoa of hagfish (see Jespersen 1975;Morisawa 1999. Presumably the peg serves to support the acrosomal vesicle or, in the case of T. (C.) maxima and T. (C.) crocea, to support and anchor the acrosomal vesicle (in these two species the peg and acrosomal vesicle exhibit a ball-insocket configuration).…”

Section: Structural Comparisonssupporting

confidence: 54%

Relevance of sperm ultrastructure to the classification of giant clams (Mollusca, Cardioidea, Cardiidae, Tridacninae)

Keys

Healy

2000

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Examination of sperm ultrastructure in six out of eight of the living species of giant clams ('Tridacnidae') supports reduction in status of the Tridacnidae to a subfamily of the Cardiidae (Tridacninae), as suggested by recent cladistic analyses based on shell, anatomical and molecular characters. Tridacninae spermatozoa are all of the aquasperm type, featuring, in anterior-posterior sequence: a conical acrosomal vesicle, an oblong to rod-shaped nucleus, a short midpiece region (proximal and distal centrioles surrounded by four round mitochondria); and a flagellum (9 + 2 pattern axoneme). Substantial differences occur between species with respect to the shape and length of the nucleus, and in the spatial relationship between the acrosomal complex and the nuclear apex. Although the two extant genera can be distinguished on sperm features -Tridacna, nuclear peg associated with acrosome, centriolar connective absent; Hippopus, nuclear peg absent, connective present -no defining feature of the Tridacninae can be detected. Within Tridacna, the species T. (Chametrachea) maxima and T. (C.) crocea are distinguished from other species of the genus by a much finer nuclear peg and a considerably smaller acrosome. In contrast, and against expectation, T. (C.) squamosa shows acrosomal and nuclear dimensions very close to those obtained for T. (Tridacna) gigas. Recently proposed phylogenies and classificatory changes for 'tridacnids' are discussed in the light of available sperm data.

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Section: Structural Comparisonssupporting

confidence: 54%

Relevance of sperm ultrastructure to the classification of giant clams (Mollusca, Cardioidea, Cardiidae, Tridacninae)

Keys

Healy

2000

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“…A peculiar layer is localized on the egg surface and is limited to the area beneath the forming micropyle during late oogenesis (Morisawa 1999b). The spermatozoa possess long heads and midpieces (Jespersen 1975; Morisawa 1995) and the acrosomes produce acrosomal processes from the amorphous subacrosomal material during the acrosome reaction (Morisawa 1999a); this acrosome reaction is similar to that described for spermatozoa of marine invertebrates (Dan 1970; Longo 1987). However, acrosomal exocytosis leaves many vesicles in the apical region of the sperm, suggesting the possibility of initial vesiculation (Morisawa 1999a).…”

Section: Introductionmentioning

confidence: 78%

Acrosome reaction in spermatozoa from hagfish (Agnatha) Eptatretus burgeri and Eptatretus stouti: Acrosomal exocytosis and identification of filamentous actin

Morisawa

Cherr

2002

Dev Growth Differ

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Spermatozoa of the hagfishes Eptatretus burgeri and Eptatretus stouti , caught in the sea near Japan and North America, respectively, were found to undergo the acrosome reaction, which resulted in the formation of an acrosomal process with a filamentous core. The acrosomal region of spermatozoa of E. stouti exhibited immunofluorescent labeling using an actin antibody. The midpiece also labeled with the antibody. The acrosomal region showed a similar labeling pattern when sperm were probed with tetramethylrhodamine isothyocyanate (TRITC)-phalloidin; the midpiece did not label. Following induction of the acrosome reaction with the calcium (Ca 2+ ) ionophore ionomycin, TRITC-phalloidin labeling was more intense in the acrosomal region, suggesting that the polymerization of actin occurs during formation of the acrosomal process, as seen in many invertebrates. The potential for sperm to undergo acrosomal exocytosis was already acquired by late spermatids. During acrosomal exocytosis, the outer acrosomal membrane and the overlying plasma membrane disappeared and were replaced by an array of vesicles; these resembled an early stage of the acrosome reaction in spermatozoa of higher vertebrates in which no formation of an acrosomal process occurs. It is phylogenetically interesting that such phenomena occur in spermatozoa of hagfish, a primitive vertebrate positioning between invertebrates and high vertebrates.

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“…In B. lenok, tsinlingensis, the nucleus almost fully occupies the entire head portion and the nuclear fossa is located at the base of the head; the depress aspect of which is deep, with a length of approximately one-third that of the nucleus. The relative position of the centriolar complex is species specific and it can range from parallel to perpendicular (Morisawa, 1999). In B. lenok tsinlingensis, the centriolar complex lies inside the nuclear fossa with vertically aligned centrioles at 90 • .…”

Section: Discussionmentioning

confidence: 99%

Morphology and ultrastructure of Brachymystax lenok tsinlingensis spermatozoa by scanning and transmission electron microscopy

Guo

Shao

et al. 2016

Tissue and Cell

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Acrosome reaction in spermatozoa of the hagfish Eptatretus burgeri (Agnatha)

Cited by 17 publications

References 14 publications

Relevance of sperm ultrastructure to the classification of giant clams (Mollusca, Cardioidea, Cardiidae, Tridacninae)

Relevance of sperm ultrastructure to the classification of giant clams (Mollusca, Cardioidea, Cardiidae, Tridacninae)

Acrosome reaction in spermatozoa from hagfish (Agnatha) Eptatretus burgeri and Eptatretus stouti: Acrosomal exocytosis and identification of filamentous actin

Morphology and ultrastructure of Brachymystax lenok tsinlingensis spermatozoa by scanning and transmission electron microscopy

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