Oscine Spermatozoa: A Light- and Electron-Microscopy Study

Henley, Catherine; Feduccia, Alan; Costello, Donald P.

doi:10.2307/1367789

Cited by 31 publications

(23 citation statements)

References 3 publications

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“…The spermatozoa of the oscine group have been better studied ultrastructurally. 55,59,[70][71][72][73] These works will provide the reference points for description, nomenclature and discussion of spermiogenesis in passerine birds. Thus far, only Go es and Dolder 41 have given a relatively full account of spermiogenesis in a passerine bird, others being more fragmentary or superficial, in nature.…”

Section: Passerine Birdsmentioning

confidence: 99%

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Spermiogenesis in birds

Aire

2014

Spermatogenesis

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Current knowledge on avian spermiogenesis, including strengths and weaknesses, has been reviewed. Information on avian spermiogenesis considerably lags behind that in mammals because of the paucity of reports in birds. Spermiogenesis in passerine birds has received even much less attention than in non-passerine birds. Mechanisms underlying morphogenesis of the acrosome and nucleus, and roles of microtubular assemblies are poorly understood. The proximal centriole found in non-passerine birds, but hitherto considered to be absent in passerine birds, has recently been described in spermatids and mature spermatozoa of 2 passeridan species, including the Masked weaver for which new and detailed spermiogenetic information is provided in this review. A great deal more studies on spermiogenesis, and spermatogenesis generally, in various avian species are required to considerably enhance knowledge of this phenomenon, contribute to comparative spermatology, provide a basis for appropriate applied studies, and contribute to understanding of phylogeny in this vast order of vertebrates.

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Section: Passerine Birdsmentioning

confidence: 99%

“…59,71,74 The nucleus is also helical in shape, and shorter than that of non-passerine birds. 75 The helical acrosome has been reported to be much longer than the nucleus, with an acrosome : nucleus ratio exceeding 1 (see Jamieson 55 for details).…”

Section: Oscine Spermatozoamentioning

confidence: 99%

Spermiogenesis in birds

Aire

2014

Spermatogenesis

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“…The acrosome of the budgerigar, parrots and cockatiel, although also conical in form, does not form a cap over the tip of the nucleus as described in ratites, but ends adjacent to the nucleus without overlapping it [19][20][21]. Not all non-passerines have a cap-like acrosome, for example, in the white-naped crane [22], jacana [23] and woodpecker [24], a small spherical, button-like acrosome has been described which nestles at the blunt apex of the nucleus. These species are considered to be advanced nonpasserines on the basis of DNA studies [25].…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

“…A typical perforatorium, therefore, appears to be absent in emu sperm. This situation is not unique to the emu as there are some non-passerine species that lack a perforatorium, for example, the woodpecker [24] and jacana [23,26]. These species characteristically display a button-like acrosome and not the conical acrosome associated with a nuclear rostrum typical of the palaeognaths.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

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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“…It is therefore clear that our knowledge of spermatogenesis and spermatozoal structure in this order is considerably limited. According to Henley et al (1978), "it is surprising that so little has been done to reveal the ultrastructure of oscine spermatozoa and to study further the arrangement of sperm within the testes". Yet, in the few reports on passerine spermatogenesis and sperm structure, there are a number of reported differences in organelle disposition and interpretation (Fawcett et al 1971;Goés and Dolder 2002;Humphreys 1972;Jamieson et al 2006;Kondo et al 1988;Nicander 1970;Sotelo and Trujillo-Cenóz 1958;Tripepi and Perotta 1991;Yasuzumi 1956;Yasuzumi and Sugioka 1971).…”

Section: Introductionmentioning

confidence: 99%

Components and development of the centriolar complex during and beyond spermiogenesis in a passeridan bird, the Masked weaver (Ploceus velatus)

Aire

Ozegbe

2012

Tissue and Cell

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The fate of the proximal centriole in passeridan birds is an area of controversy and relative lack of knowledge in avian spermatogenesis and spermatology. This study examines, for the first time, spatiotemporal changes in the centriolar complex in various phases of spermiogenesis in a passerine bird, the Masked weaver (Ploceus velatus). It also describes the configuration of the centriolar complex and the relationship between it and the granular body in both intra-and extra-testicular spermatozoa. It is shown that the proximal centriole is retained and attaches, at its free end, to the granular body of spermatids in every step of spermiogenesis, as well as in mature intra-testicular and post-testicular spermatozoa, including those in the lumen of the seminal glomus. As the centriolar complex, along with its attached granular body, approaches the nucleus in the early spermatid, the proximal centriole articulates with the distal centriole at an acute angle of about 45⁰, and thereafter, both centrioles, still maintaining this conformation, implant, by means of their articulating proximal ends, at the implantation fossa of the nucleus.In the mature spermatid and spermatozoon, the granular body winds itself helically around the centriolar complex in the neck/midpiece region of the cell, and, thus, becomes the granular 2 helix. The significance of this observation must await future studies, including possible phylogenetic re-evaluation and classification of birds.

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Oscine Spermatozoa: A Light- and Electron-Microscopy Study

Cited by 31 publications

References 3 publications

Spermiogenesis in birds

Spermiogenesis in birds

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

Components and development of the centriolar complex during and beyond spermiogenesis in a passeridan bird, the Masked weaver (Ploceus velatus)

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