scholarly journals Sperm ultrastructure in arrhenotokous and thelytokous Thysanoptera

2021 ◽  
Vol 64 ◽  
pp. 101084
Author(s):  
Stephanie Krueger ◽  
Gerald Moritz
Keyword(s):  
Sperm Ultrastructure

Spermiogenesis and sperm ultrastructure of Carmyerius endopapillatus (Digenea, Gastrothylacidae), a parasite of Bos taurus in Senegal

2008 ◽  
Vol 53 (1) ◽  
Author(s):  
Momar Seck ◽  
Bernard Marchand ◽  
Cheikh Bâ
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Bos Taurus ◽  
Posterior Extremity ◽  
Sperm Ultrastructure ◽  
Lateral Expansion ◽  
Transmission Electron ◽  
Plasmic Membrane ◽  
Flagellar Rotation

AbstractUltrastructural study of spermiogenesis and of the spermatozoon of Carmyerius endopapillatus has enabled to describe some characteristics of this digenea. The intercentriolar body situated between the two striated roots and the two centrioles, presents a symmetric organization. Both external bands of this intercentriolar body are made up of a row of granules. During spermiogenesis, a flagellar rotation of 90° is described. The old spermatid does not present external ornamentations. The spermatozoon is characterized, in its anterior region, by the presence of a lateral expansion exhibiting one spinelike body. In C. endopapillatus, external ornamentations are localized only at the level where the lateral expansion appears. The posterior extremity of spermatozoon exhibits a nucleus surrounded by a plasmic membrane lacking microtubules, but presenting a small lateral expansion. This is the first species of Gastrothylacidae family studied by transmission electron microscopy.

Spermatogenesis and the fine structure of the mature spermatozoon of the liver fluke, Fasciola hepatica (Trematoda: Digenea)

Parasitology ◽  
1990 ◽  
Vol 101 (3) ◽  
pp. 395-407 ◽  
Author(s):  
A. W. Stitt ◽  
I. Fairweather
Keyword(s):  
Fine Structure ◽  
Liver Fluke ◽  
Central Body ◽  
Fasciola Hepatica ◽  
Mature Spermatozoon ◽  
Basal Bodies ◽  
Nuclear Region ◽  
Sperm Ultrastructure ◽  
Transmission Electron ◽  
Median Process

SUMMARYSpermatogenesis and the fine structure of the mature spermatozoon of Fasciola hepatica have been studied by transmission electron microscopy. The primary spermatogonia display a typical gonial morphology and occupy the periphery of the testis. They undergo 3 mitotic divisions to give rise to 8 primary spermatocytes forming a rosette of cells connected to a central cytophore. The primary spermatocytes undergo 2 meiotic divisions, resulting in 32 spermatids that develop into spermatozoa. Intranuclear synaptonemal complexes in primary spermatocytes confirm the first meiotic division. The onset of spermiogenesis is marked by the formation of the zone of differentiation which contains 2 basal bodies and a further centriole derivative, the central body. The zone extends away from the spermatid cell to form the median process; into this migrates the differentiated and elongate nucleus. Simultaneously, 2 axonemes develop from the basal bodies. During development, they rotate through 90° to extend parallel to the median process. The migration of the nucleus to the distal end of the median process coincides with the fusion of the axonemes to the latter to form a monopartite spermatozoon. The mature spermatozoon possesses 2 axonemes of the 9 + ‘1’ pattern typical of parasitic platyhelminths, 2 elongate mitochondria and a variable array of peripheral microtubules. The nuclear region of the spermatozoon is immotile. The value of sperm ultrastructure as a taxonomic tool in platyhelminth phylogeny is discussed.

Sperm ultrastructure, morphometry, and abnormal morphology in American black bears (Ursus americanus)

2010 ◽  
Vol 74 (8) ◽  
pp. 1403-1413 ◽  
Author(s):  
L.F.C. Brito ◽  
P.L. Sertich ◽  
G.B. Stull ◽  
W. Rives ◽  
M. Knobbe
Keyword(s):  
Ursus Americanus ◽  
Black Bears ◽  
Sperm Ultrastructure ◽  
Abnormal Morphology ◽  
American Black ◽  
American Black Bears

scholarly journals Sperm ultrastructure of Pochazia shantungensis (Chou & Lu) and Ricania speculum (Walker) (Hemiptera, Ricaniidae) with phylogenetic implications

ZooKeys ◽  
2019 ◽  
Vol 880 ◽  
pp. 43-59
Author(s):  
Zhen Jiang ◽  
Jianing Liu ◽  
Daozheng Qin
Keyword(s):  
Neck Region ◽  
Mature Spermatozoon ◽  
Current Evidence ◽  
Sperm Ultrastructure ◽  
Transmission Electron ◽  
Phylogenetic Implications ◽  
Dense Substance ◽  
The Individual ◽  
Relationship Of ◽  
Centriole Adjunct

The sperm ultrastructure of two ricaniid species, Pochazia shantungensis (Chou & Lu) and Ricania speculum (Walker), was investigated using light and transmission electron microscopy. Both species have monoflagellate sperm, the shape and ultrastructure of the mature spermatozoon of these two species are similar in morphology, and 128 spermatozoa are organized into sperm bundles with their heads embedded in a homogenous matrix forming the spermatodesmata. The individual sperm is filiform and includes the head, neck and flagellum. The head is needle-like, with a bilayer acrosome and an inferior elongated nucleus which is formed of homogeneously compact and electron-dense chromatin. The neck region is indistinct and is comprised of the centriole and centriole adjunct with a homogeneous dense substance. The long flagellum has the typical 9 + 9 + 2 axoneme microtubule pattern and two symmetrical mitochondrial derivatives with an orderly array of cristae flanking both sides, and a pair of well-developed fishhook-shaped accessory bodies. Current evidence shows that ricaniid species have D-shaped mitochondrial derivatives in cross-section and a serrated electron-dense region. The phylogenetic relationship of Fulgoroidea with other superfamilies in Auchenorrhyncha is briefly discussed.

Comparative sperm ultrastructure in Nemertea

2010 ◽  
Vol 271 (7) ◽  
pp. 793-813 ◽  
Author(s):  
J. von Döhren ◽  
P. Beckers ◽  
R. Vogeler ◽  
T. Bartolomaeus
Keyword(s):  
Sperm Ultrastructure
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