Spermatozoal ultrastructure in three species of parrots (Aves, psittaciformes) and its phylogenetic implications

Jamieson, B. G. M.; Koehler, Lawrence D.; Todd, Bethwyn J.

doi:10.1002/ar.1092410404

Cited by 18 publications

(31 citation statements)

References 32 publications

(59 reference statements)

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“…In common with other ratites the nuclear rostrum in emu sperm extends deep within the acrosome, resulting in the lateral profiles of the acrosome thinning towards the acrosome-nuclear shoulder. 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.…”

Section: Transmission Electron Microscopymentioning

confidence: 98%

“…In some galliform birds, such as the chicken, it extends approximately halfway beneath the acrosome, whereas in the turkey [30], duck [31] and white-necked crane [22] the perforatorium is comparatively short and limited to the posterior aspect of the acrosome. In the budgerigar [19] and parrots [20], it is an extremely long structure, extending almost the full length of the sub-acrosomal region. The situation in palaeognaths is strikingly different.…”

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: 98%

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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“…In addition, the rostrum in ratites bears an equally extensive endonuclear canal. It is noteworthy that the anterior tip of the nucleus of the Budgerigar, 28,135 white-naped Crane, 136 cockatiel (Fig. 10F, G), and peach-faced lovebird 45,135 does not project into the subacrosomal space, as in other birds, but makes a direct, en face contact with the caudal rim of the acrosome.…”

Section: -126mentioning

confidence: 99%

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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“…However, the concentration of intermediate filaments denoting this region as the acroplaxome in rodents (Kierszenbaum et al, 2003) is not observed. Whereas in mammals the acrosome covers the anterior two thirds of the nucleus, in non-passerine and sub-oscine birds it is short relative to the length of the nucleus (Jamieson et al, 1995). In ratites it covers approximately 10% of the nucleus and would therefore have little influence on head shaping in general except for the formation of the nuclear rostrum as described above.…”

Section: The Perinuclear Theca (Pt)mentioning

confidence: 99%

“…This would appear unlikely in non-passerines as a conical acrosome is formed in a number of species without the presence of a nuclear rostrum (Humphreys, 1975;Jamieson, 2007;Jamieson et al, 1995;Lovas et al, 2012;Phillips et al, 1987;Saita et al, 1982;Samour et al, 1986), although a well-developed perforatorium may fulfill this role. In these birds the acrosome ends adjacent to the nucleus and does not overlap it.…”

Section: Role Of the Forming Acrosomementioning

confidence: 99%

Sperm head shaping in ratites: New insights, yet more questions

Plessis

Soley

2016

Tissue and Cell

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Highlights• Detailed description of the various factors involved in sperm head shaping.• First report on the presence of a perinuclear theca (PT) in birds.• The PT plays a role in stabilizing the sperm head during spermiogenesis in ratites.• The elaboration of the PT may be used to resolve phylogenetic questions. 2 AbstractHead shaping in mammalian sperm is regulated by a number of factors including acrosome formation, nuclear condensation and the action of the microtubular manchette. A role has also been suggested for the attendant Sertoli cells and the perinuclear theca (PT). In comparison, relatively little information is available on this topic in birds and the presence of a PT per se has not been described in this vertebrate order. This study revealed that a similar combination of factors contributed to head shaping in the ostrich, emu and rhea, although the Sertoli cells seem to play a limited role in ratites. A fibro-granular structure analogous to the mammalian PT was identified, consisting of sub-and post-acrosomal components. The latter was characterized by stage-specific finger-like projections that appeared to emanate from the cytoplasmic face of the nuclear envelope. They were particularly obvious beneath the base of the acrosome, and closely aligned, but not connected to, the manchette microtubules. During the final stages of chromatin condensation and elongation of the sperm head the projections abruptly disappeared. They appear to play a role in stabilizing the shape of the sperm head during the caudal translocation of the spermatid cytoplasm.

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Spermatozoal ultrastructure in three species of parrots (Aves, psittaciformes) and its phylogenetic implications

Cited by 18 publications

References 32 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 birds

Sperm head shaping in ratites: New insights, yet more questions

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