Ultrastructure of spermatozoa of the crested tinamou

Asa, Cheryl; Phillips, David M.; Stover, Janet

doi:10.1016/0889-1605(86)90063-7

Cited by 29 publications

(47 citation statements)

References 19 publications

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“…It has been described in the ostrich [12,13], rhea [18], tinamou [36] and emu [12,present study] and lies perpendicular to the proximal centriole. In other non-passerines such as the chicken [28], duck [33,41], turkey [30] and budgerigar [19], the distal centriole is restricted to the anterior region of the midpiece.…”

Section: Transmission Electron Microscopymentioning

confidence: 51%

“…The microtubules were continuous, in the vicinity of the annulus, with the central pair of axonemal microtubules as also described for the ostrich [13], rhea [18] and tinamou [36]. In the rhea the central microtubules do not appear to be embedded in a rod of dense material [18].…”

Section: Transmission Electron Microscopymentioning

confidence: 54%

“…The situation in palaeognaths is strikingly different. In the tinamou the endonuclear canal is a slim, centrally positioned, tube-like structure that extends the complete length of the nucleus [36], whereas in the ostrich [12,13] and rhea [18] it is shorter and only extends part of the way into the nucleus. The endonuclear canal is filled with moderately electron dense material analogous to the perforatorium of neognaths.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

“…This variation in number can be attributed to either the mitochondria in the emu being smaller than those of other ratites, or to the absence of inter-mitochondrial cement in the emu, which is present in both the ostrich [13] and rhea [18]. Similarly, the tinamou also has fewer mitochondria in the midpiece as well as inter-mitochondrial cement [36]. Other non-passerines such as the chicken [30], turkey [30,42], duck [41] and guinea fowl [30] also have fewer mitochondria (25)(26)(27)(28)(29)(30) in the midpiece when compared to the emu, despite midpiece length being similar.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

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A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae

Plessis

Soley

2014

Theriogenology

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Existing reports on sperm structure in the emu do not adequately illustrate or describe all the salient ultrastructural features necessary for a meaningful comparison of normal and abnormal sperm in this species. As sperm morphology forms an important parameter in determining semen quality, and in view of the proposed role of artificial insemination in the farming of ratites, this paper re-evaluates and complements the existing data on the topic, provides a fully illustrated description of emu sperm ultrastructure and documents some unreported morphological features. Conventional transmission (TEM) and scanning (SEM) electron microscopy, as well as high resolution SEM, was used to describe the ultrastructure of sperm harvested from the distal deferent duct of sexually mature birds slaughtered during the breeding season. In addition to broadly confirming the basic ultrastructural characteristics previously described for emu sperm, this study revealed a number of unreported morphological features. These included distinct differences in surface properties between the acrosome and nucleus, the presence of a thread-like appendage near the base of the nucleus, variable positioning of the annulus relative to structures located at the midpiece -principal 1 piece junction and regional differentiation of the principal piece. Although the emu displayed similar basic morphological features to sperm of other ratites and the tinamou, marked structural peculiarities were obvious, notably the lack of an endonuclear canal and a perforatorium as well as the presence of significantly more mitochondria in the midpiece coupled with an absence of inter-mitochondrial cement. Whereas the broad morphological features of emu sperm would appear to add credence to the general view that the ratites, together with the tinamous, form a monophyletic group at the base of the avian phylogenetic tree, it is also clear that emu sperm are distinctly different from those of the ostrich, rhea and tinamou which together share morphological affinities This observation may lend some support to the alternate view that the Australasian ratites represent a separate clade that developed independently from flightless ancestors.

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Section: Transmission Electron Microscopymentioning

confidence: 51%

Section: Transmission Electron Microscopymentioning

confidence: 54%

Section: Transmission Electron Microscopymentioning

confidence: 99%

Section: Transmission Electron Microscopymentioning

confidence: 99%

See 2 more Smart Citations

A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae

Plessis

Soley

2014

Theriogenology

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“…However, several structures are uniquely different from those seen in mammalian and even other reptilian spermatozoa (Fawcett, 1970;Asa et al, 1986;Philips and Asa, 1989;Cai et al, 1997;Liu et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Spermiogenesis in Soft‐Shelled Turtle, Pelodiscus sinensis

Zhang

Han

et al. 2007

The Anatomical Record

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Spermiogenesis in the soft-shelled turtle, Pelodiscus sinensis, was examined by transmission electron microscopy. The process includes nuclear elongation, chromatin condensation, acrosomal and flagellar development, and elimination of excess cytoplasm. In stage I, the proacrosomal vesicle occurs next to a shallow fossa of the nucleus, and a dense acrosomal granule forms beneath it. A smaller subacrosomal granule in the middle of the fibrous layer is related to the development of intranuclear tubules. The nucleus begins to move eccentrically. In stage II, the round proacrosomal vesicle is flattened by protrusion of the nuclear fossa, and the dense acrosomal granule diffuses into the vesicle, as the fibrous layer forms the subacrosomal cone. Circular manchettes develop around the nucleus, and the chromatin coagulates into small granules. The movement of the nucleus causes rearrangement of the cytoplasm. In stage III, the front of the elongating nucleus protrudes out of the spermatid and is covered by the flat acrosome; coarse granules replace the small ones within the nucleus. At the posterior pole of the head, mitochondria move backward. Numerous microtubules begin to assemble the axoneme of flagellum. In stage IV, the chromatin concentrates to dense homogeneous phase. The circular manchette is reorganized longitudinally. The Sertoli process covers the acrosome and the residues of the cytoplasmic lobes are eliminated. In stage V, the sperm head matures. After dissolution of the longitudinal manchette, the mitochondria arrange themselves around the proximal and distal centrioles. Caudal to the mitochondrial mass, a fibrous sheath surrounds the proximal portion of the flagellum. Anat Rec,

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Differentiation of the acrosomal complex in ostrich (Struthio camelus) spermatids

Soley

1996

J. Morphol.

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Ultrastructure of spermatozoa of the crested tinamou

Cited by 29 publications

References 19 publications

A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae

A re-evaluation of sperm ultrastructure in the emu, Dromaius novaehollandiae

Spermiogenesis in Soft‐Shelled Turtle, Pelodiscus sinensis

Differentiation of the acrosomal complex in ostrich (Struthio camelus) spermatids

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