Ultrastructure of spermatogenesis and the mature spermatozoon of Haplobothrium globuliforme Cooper, 1914 (Cestoda: Haplobothrioidea)

1985 ◽  
Vol 63 (6) ◽  
pp. 1478-1487 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Michael D. B. Burt
Keyword(s):  
Volume Ratio ◽  
Mature Spermatozoon ◽  
Nuclear Volume ◽  
Sperm Cells ◽  
Basal Bodies ◽  
Sperm Ultrastructure ◽  
Cytoplasmic Extension ◽  
Transmission Electron ◽  
Regular Arrangement ◽  
Dense Nucleus

The process of spermatogenesis and the structure of the mature spermatozoon of Haplobothrium globuliforme Cooper, 1914 were examined using transmission electron microscopy. Spermatogonia have a low cytoplasmic to nuclear volume ratio, and contain numerous free ribosomes and few mitochondria. Quaternary spermatogonia have a rosette appearance with the eight nuclei surrounding a central cytoplasmic cytophore. Spermatocytes, the largest of the developing sperm cells, contain free ribosomes and several mitochondria with pronounced cristae. No synaptonemal complexes and few endoplasmic reticulum formations were seen. Early spermatids show a regular arrangement of the nucleus, Golgi apparatus, and mitochondria. This regularity is disrupted as spermiogenesis commences, with the formation of the zone of differentiation, a conical indentation of the spermatid cytoplasm. This zone of differentiation is bordered by microtubules. Within the zone develop two interconnected basal bodies with their respective flagellar rootlets. From each basal body arises an axoneme with the 9 + "1" microtubular configuration. The axonomes elongate, eventually fusing with a cytoplasmic extension of the zone of differentiation, and the condensed nucleus migrates into the sperm body. The mature spermatozoon is elongate (30 μm long) and slender, and possesses an electron-dense nucleus, two lateral axonemes, α and β glycogen, and peripheral microtubules. The importance of sperm ultrastructure with respect to phylogeny is discussed.

Spermiogenesis in two paramphistomes from Nile fish in Egypt: an ultrastructural study

2007 ◽  
Vol 81 (3) ◽  
pp. 219-226 ◽  
Author(s):  
A.A. Ashour ◽  
K. Garo ◽  
I.S. Gamil
Keyword(s):  
Electron Microscopy ◽  
Mature Spermatozoon ◽  
Basal Bodies ◽  
Sperm Ultrastructure ◽  
Parasitic Helminths ◽  
Ultrastructural Studies ◽  
Cytoplasmic Extension ◽  
Transmission Electron ◽  
Digenetic Trematodes ◽  
External Ornamentation

AbstractThe process of spermiogenesis in two paramphistomes,Sandonia sudanensisandBasidiodiscus ectorchisfrom the Nile fishSynodontis schallin Egypt was studied by transmission electron microscopy. Spermiogenesis is characterized by the outgrowth of the zone of differentiation, presenting two basal bodies separated by a microtubule organizing centre, each basal body developing into a flagellum. Proximodistal fusion of these flagella with a median cytoplasmic extension gives rise to the spermatozoon. The mature spermatozoon possesses two axonemes of the 9+‘1’ pattern typical of parasitic helminths. There are few ultrastructural studies on spermiogenesis in paramphistomes, which are considered the most primitive digenetic trematodes. The present study provides new and more detailed information on this process, including the presence of a lateral flange and external ornamentation of the cell membrane. The value of sperm ultrastructure as a taxonomic tool in phylogeny is also discussed.

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.

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.

Spermiogenesis and spermatozoon of the tapeworm Parabothriocephalus gracilis (Bothriocephalidea): Ultrastructural and cytochemical studies

2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Lenka Šípková ◽  
Céline Levron ◽  
Mark Freeman ◽  
Tomáš Scholz
Keyword(s):  
Electron Microscopy ◽  
Anterior Extremity ◽  
Mature Spermatozoon ◽  
Dense Material ◽  
Apical Region ◽  
Cortical Microtubules ◽  
Electron Dense Material ◽  
Dense Granules ◽  
Cytoplasmic Extension ◽  
Transmission Electron

AbstractSpermiogenesis and spermatozoon ultrastructure of the tapeworm Parabothriocephalus gracilis were described using transmission electron microscopy (TEM). Spermiogenesis is characterized by the formation of a zone of differentiation with two centrioles associated with striated rootlets, and an intercentriolar body between them. The two flagella undergo a rotation of 90° until they become parallel to the median cytoplasmic extension with which they fuse. Electron-dense material is present in the apical region of the zone of differentiation in the early stages of spermiogenesis. This electron-dense material is characteristic for the orders Bothriocephalidea and Diphyllobothriidea. The mature spermatozoon contains two axonemes of the 9 + ‘1’ trepaxonematan pattern, nucleus, parallel cortical microtubules and electron-dense granules of glycogen. The anterior extremity of the spermatozoon exhibits a single helical electron-dense crested body 130 nm thick. One of the most interesting features is the presence of a ring of cortical microtubules surrounding the axoneme. This character has been reported only for species of the order Bothriocephalidea and may be unique in this cestode group.

Microscopic Characterization of a Sperm Mutant Line of the Fern Ceratopteris Richardii

2000 ◽  
Vol 6 (S2) ◽  
pp. 700-701
Author(s):  
Kelly A. Davidson ◽  
Leslie G. Hickok ◽  
Karen S. Renzaglia
Keyword(s):  
Mutant Line ◽  
Sperm Cells ◽  
Basal Bodies ◽  
Ceratopteris Richardii ◽  
Rhodamine Phalloidin ◽  
Transmission Electron ◽  
Cell Organization ◽  
Light Fluorescence ◽  
Dapi Fluorescence

Mature sperm cells of Ceratopteris richardii are spiraled over three revolutions and contain a locomotory apparatus with approximately 70 flagella attached at the cell anterior (Fig. 1). Abundant organelles are dispersed along the inner surface of an elongated, coiled nucleus (Figs. 1, 3, 8). The cytoskeleton comprises a network of microfilaments that encases the nucleus (Fig. 6) and two distinct microtubule arrays: a microtubular ribbon (spline) and flagella with anchoring basal bodies (Fig. 3). This study uses light, fluorescence, transmission electron (TEM), and scanning electron microscopy (SEM) to characterize cell organization in a motility impaired sperm mutant line of Ceratopteris. Because motility mutations likely involve the cytoskeleton, emphasis was placed on observing microtubule and actin arrays in the mutant compared to wild-type sperm cells. Protocols follow Hoffman and Vaughn for TEM and Schmitt and Renzaglia for SEM. Microfilament arrays in relation to the nucleus were examined by rhodamine-phalloidin and DAPI fluorescence.

TEM observation of iron oxide pillars in montmorillonite

1990 ◽  
Vol 48 (4) ◽  
pp. 882-883
Author(s):  
H. Mori ◽  
Y. Murata ◽  
H. Yoneyama ◽  
H. Fujita
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Fine Particles ◽  
Aqueous Suspension ◽  
Volume Ratio ◽  
Exchange Capacity ◽  
Nano Composites ◽  
Pillared Montmorillonite ◽  
Topographic Features ◽  
Transmission Electron

Recently, a new sort of nano-composites has been prepared by incorporating such fine particles as metal oxide microcrystallites and organic polymers into the interlayer space of montmorillonite. Owing to their extremely large specific surface area, the nano-composites are finding wide application[1∼3]. However, the topographic features of the microstructures have not been elucidated as yet In the present work, the microstructures of iron oxide-pillared montmorillonite have been investigated by high-resolution transmission electron microscopy.Iron oxide-pillared montmorillonite was prepared through the procedure essentially the same as that reported by Yamanaka et al. Firstly, 0.125 M aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate, [Fe3(OCOCH3)7 OH.2H2O]NO3, was prepared and then the solution was mixed with an aqueous suspension of 1 wt% clay by continuously stirring at 308 K. The final volume ratio of the latter aqueous solution to the former was 0.4. The clay used was sodium montmorillonite (Kunimine Industrial Co.), having a cation exchange capacity of 100 mequiv/100g. The montmorillonite in the mixed suspension was then centrifuged, followed by washing with deionized water. The washed samples were spread on glass plates, air dried, and then annealed at 673 K for 72 ks in air. The resultant film products were approximately 20 μm in thickness and brown in color.

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.

In-Situ Transmission Electron Microscopy of the Formation of Metal-Semiconductor Contacts

1990 ◽  
Vol 181 ◽  
Author(s):  
J. M. Gibson ◽  
D. Loretto ◽  
D. Cherns
Keyword(s):  
High Surface ◽  
High Vacuum ◽  
Volume Ratio ◽  
Ultra High Vacuum ◽  
Silicon Surfaces ◽  
Transmission Electron ◽  
Metal Silicides ◽  
Phase Sequence ◽  
Semiconductor Contacts

ABSTRACTWe have studied the formation of metal silicides in-situ in an ultra-high vacuum transmission electron microscope. Metals were deposited on in-situ cleaned, reconstructed silicon surfaces and annealed. For the metals Ni and Co, we find that the phase sequence in ultra-thin films is different from that seen in ≈1000 Å thick films, and attribute this to the high surface-to-volume ratio. In general reactions occur at room temperature, to form an epitaxial phase if possible. We report preliminary new results on the formation of Pd2Si.

scholarly journals Biallelic variants in MAATS1 encoding CFAP91, a calmodulin-associated and spoke-associated complex protein, cause severe astheno-teratozoospermia and male infertility

2020 ◽  
Vol 57 (10) ◽  
pp. 708-716 ◽  
Author(s):  
Guillaume Martinez ◽  
Julie Beurois ◽  
Denis Dacheux ◽  
Caroline Cazin ◽  
Marie Bidart ◽  
...  
Keyword(s):  
Male Infertility ◽  
Sperm Cells ◽  
Gene Encoding ◽  
Infertile Men ◽  
Transmission Electron ◽  
Complex Protein ◽  
Radial Spokes ◽  
Gene Defects ◽  
Primary Male ◽  
And Function

BackgroundMultiple morphological abnormalities of the flagella (MMAF) consistently lead to male infertility due to a reduced or absent sperm motility defined as asthenozoospermia. Despite numerous genes recently described to be recurrently associated with MMAF, more than half of the cases analysed remain unresolved, suggesting that many yet uncharacterised gene defects account for this phenotypeMethodsExome sequencing was performed on 167 infertile men with an MMAF phenotype. Immunostaining and transmission electron microscopy (TEM) in sperm cells from affected individuals were performed to characterise the ultrastructural sperm defects. Gene inactivation using RNA interference (RNAi) was subsequently performed in Trypanosoma.ResultsWe identified six unrelated affected patients carrying a homozygous deleterious variants in MAATS1, a gene encoding CFAP91, a calmodulin-associated and spoke-associated complex (CSC) protein. TEM and immunostaining experiments in sperm cells showed severe central pair complex (CPC) and radial spokes defects. Moreover, we confirmed that the WDR66 protein is a physical and functional partner of CFAP91 into the CSC. Study of Trypanosoma MAATS1’s orthologue (TbCFAP91) highlighted high sequence and structural analogies with the human protein and confirmed the axonemal localisation of the protein. Knockdown of TbCFAP91 using RNAi impaired flagellar movement led to CPC defects in Trypanosoma as observed in humans.ConclusionsWe showed that CFAP91 is essential for normal sperm flagellum structure and function in human and Trypanosoma and that biallelic variants in this gene lead to severe flagellum malformations resulting in astheno-teratozoospermia and primary male infertility.

The comparative ultrastructure of spermatozoa from Bothrimonus sturionis Duv. 1842 (Pseudophyllidea), Pseudanthobothrium hanseni Baer, 1956 (Tetraphyllidea), and Monoecocestus americanus Stiles, 1895 (Cyclophyllidea)

1984 ◽  
Vol 62 (6) ◽  
pp. 1059-1066 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Michael D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plasma Membrane ◽  
Main Body ◽  
Posterior Portion ◽  
Transmission Electron ◽  
Dense Nucleus ◽  
Comparative Ultrastructure ◽  
Electron Lucent ◽  
Mature Spermatozoa

The mature spermatozoa from Bothrimonus sturionis (Pseudophyllidea), Pseudanthobothrium hanseni (Tetraphyllidea), and Monoecocestus americanus (Cyclophyllidea) were examined using transmission electron microscopy. Transverse sections of the sperm of B. sturionis indicate that the number of sperm axonemes varies from one to eight, with approximately one-third of the sperm containing two axonemes. Likewise, the number of peripheral microtubules lying just within the external plasma membrane varies from 12 to 20. The nucleus is electron lucent and fibrous in appearance. The spermatozoa of B. sturionis show great variation in the material examined and the majority of them are believed to be aberrant. The spermatozoon of P. hanseni contains a single axoneme with the nucleus wrapped in a crescent around it in the anterior region of the sperm. The posterior portion of the spermatozoon is characterized by a helical flange which projects from the main body of the sperm. The spermatozoon of M. americanus is elongate and slender, containing a single axoneme with an electron-dense nucleus coiled around it in the anterior one-third of the sperm. Electron-opaque bodies, which may be glycogen, fill the cytoplasm. The spermatozoa of all three species contain neither an acrosome nor mitochondria. The flagella of all the spermatozoa have a 9 + "1" arrangement of microtubules. The importance of the ultrastructure of spermatozoa in the phylogeny and taxonomy of cestodes is discussed.

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