The ultrastructure of spermatogenesis and spermatozoa in Pseudodiplorchis americanus (Monogenea: Polystomatidae)

1993 ◽  
Vol 71 (8) ◽  
pp. 1609-1619 ◽  
Author(s):  
J. Cable ◽  
R. C. Tinsley
Keyword(s):  
General Pattern ◽  
Adult Life ◽  
Mature Spermatozoon ◽  
Structural Features ◽  
Taxonomic Position ◽  
Cortical Microtubules ◽  
Standard Pattern ◽  
Male Gametes ◽  
Basic Characteristics ◽  
Mature Spermatozoa

The basic characteristics of spermatogenesis and the ultrastructure of the mature spermatozoa show uniformity throughout the parasitic platyhelminths, and the monogenean Pseudodiplorchis americanus follows this general pattern. Primary spermatogonia undergo mitosis to produce 8 primary spermatocytes which divide by meiosis to produce 16 secondary spermatocytes and eventually a syncytial rosette of 32 spermatids. Each spermatid differentiates into a mature spermatozoon bearing two axonemes, a nucleus, a mitochondrion, and cortical microtubules. Although transmission of P. americanus is restricted to only a few nights each year, the production of male gametes appears to be continuous throughout adult life and exhibits no seasonality. Characteristically, cortical microtubules run the entire length of polyopisthocotylean spermatozoa but they are absent along part of the spermatozoon of P. americanus and one other polystomatid species previously examined. This variation on the standard pattern separates the Polystomatidae from the rest of the Monogenea and emphasises the distinctive taxonomic position and the homogeneity of many structural features within this platyhelminth family.

scholarly journals A comparative study of the ultrastructural characteristics of the mature spermatozoa of two fellodistomids Tergestia clonacantha and T. laticollis and contribution to the phylogenetic knowledge of the Gymnophalloidea

Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 67
Author(s):  
Papa Ibnou Ndiaye ◽  
Bernard Marchand ◽  
Cheikh Tidiane Bâ ◽  
Jean-Lou Justine ◽  
Rodney Alan Bray ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
New Caledonia ◽  
General Pattern ◽  
Mature Spermatozoon ◽  
Cortical Microtubules ◽  
Transmission Electron ◽  
Ultrastructural Model ◽  
Ultrastructural Characteristics ◽  
External Ornamentation ◽  
Mature Spermatozoa

The ultrastructure of the mature spermatozoa of Tergestia clonacantha and T. laticollis collected from the digestive tracts of fishes from New Caledonia is described using transmission electron microscopy and compared to that of related species. The spermatozoa of the two species exhibit the general pattern described in most digeneans, namely two axonemes with the 9 + “1” pattern of the Trepaxonemata, nucleus, mitochondrion, cortical microtubules, an external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The spermatozoa of T. clonacantha and T. laticollis show the same ultrastructural model with some specificities in each case, particularly in the disposition of the structures in the posterior extremities of the spermatozoon. This study confirms that ultrastructural characters of the mature spermatozoon are useful tools for the phylogenetic analysis of the Digenea.

scholarly journals Ultrastructure of mature spermatozoa of three Bucephalidae (Prosorhynchus longisaccatus, Rhipidocotyle khalili and Bucephalus margaritae) and phylogenetic implications

Parasite ◽  
2018 ◽  
Vol 25 ◽  
pp. 65 ◽  
Author(s):  
Papa Ibnou Ndiaye ◽  
Bernard Marchand ◽  
Cheikh Tidiane Bâ ◽  
Jean-Lou Justine ◽  
Rodney A. Bray ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Anterior Extremity ◽  
Posterior Extremity ◽  
Anterior Part ◽  
Mature Spermatozoon ◽  
Cortical Microtubules ◽  
Lateral Expansion ◽  
Phylogenetic Implications ◽  
External Ornamentation ◽  
Mature Spermatozoa

We describe here the mature spermatozoa of three species of bucephalids, namely Bucephalus margaritae, Rhipidocotyle khalili and Prosorhynchus longisaccatus. This study provides the first ultrastructural data on the genera Bucephalus and Rhipidocotyle and enabled us to confirm the model of the mature spermatozoon in the Bucephalinae. The spermatozoon exhibits two axonemes with the 9 + “1” pattern of the Trepaxonemata, one of which is very short, lateral expansion, external ornamentation of the plasma membrane located in the anterior extremity of the spermatozoon and associated with cortical microtubules, spine-like bodies, a mitochondrion, and a nucleus. The maximum number of cortical microtubules is located in the anterior part of the spermatozoon. However, more studies are needed to elucidate if spine-like bodies are present in all the Bucephalinae or not. In the Prosorhynchinae, the mature spermatozoon exhibits a similar ultrastructural pattern. Some differences are observed, particularly the axoneme lengths and the arrangement of the spine-like bodies. The posterior extremity of the spermatozoon in the Bucephalinae exhibits only the nucleus, but prosorhynchines have microtubules.

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.

scholarly journals Spermiogenesis and ultrastructure of the spermatozoon of Wardula capitellata (Digenea, Mesometridae), an intestinal parasite of the sparid teleost Sarpa salpa in Senegal

2012 ◽  
Vol 57 (1) ◽  
Author(s):  
Abdoulaye Bakhoum ◽  
Papa Ndiaye ◽  
Aminata Sène ◽  
Cheikh Bâ ◽  
Jordi Miquel
Keyword(s):  
Plasma Membrane ◽  
Intestinal Parasite ◽  
Mature Spermatozoon ◽  
Cytoplasmic Process ◽  
Cortical Microtubules ◽  
Differentiation Zone ◽  
Sarpa Salpa ◽  
First Time ◽  
External Ornamentation ◽  
Free Flagellum

AbstractThe spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities such as two lateral expansions accompanied by external ornamentation of the plasma membrane and spinelike bodies characterize the mature sperm. Moreover, a new spermatological character is described for the first time, the so-called cytoplasmic ornamented buttons.

scholarly journals Ultrastructure of the mature spermatozoon of Eubothrium rugosum (Batsch, 1786) with a re-assessment of the spermatozoon ultrastructure of Eubothrium crassum (Bloch, 1779) (Cestoda: Bothriocephalidea)

2010 ◽  
Vol 47 (4) ◽  
pp. 257-263 ◽  
Author(s):  
M. Bruňanská ◽  
H.-P. Fagerholm ◽  
J. Nebesářová ◽  
B. Kostič
Keyword(s):  
Posterior Extremity ◽  
Posterior Part ◽  
Mature Spermatozoon ◽  
Structural Polymorphism ◽  
Dense Granules ◽  
Male Gametes ◽  
Transmission Electron ◽  
Anterior Ring ◽  
First Time ◽  
Region Ii

AbstractThe ultrastructure of the mature spermatozoon of the bothriocephalidean tapeworm Eubothrium rugosum, a parasite of the burbot, Lota lota (L.), was studied by transmission electron microscopy for the first time. In addition, spermatozoon ultrastructure of Eubothrium crassum has been re-assessed. New is the finding, that the mature spermatozoa of both species of the genus Eubothrium exhibit essentially the same general morphology. They are filiform cells tapering at both extremities, and they possess the two axonemes with 9+“1” pattern of Trepaxonemata, attachment zones, a nucleus, cortical microtubules (CMs), electron-dense granules, and a single crested body. Structural polymorphism of the CBs has been found within the two Eubothrium species for the first time. The anterior ring of electron-dense tubular structures surrounding a single axoneme marks the border between the two defined regions, region I and region II of the spermatozoon. This unique feature has only been observed in the Bothriocephalidea. The anuclear axoneme region II of Eubothrium spermatozoa fluently verges into a nuclear region III. The posterior part of the spermatozoon contains one-axoneme, few CMs and a posterior extremity of the nucleus that subsequently disappears. The posterior extremity of the male gametes of the genus Eubothrium exhibits elements of a disorganized axoneme which characterize also spermatozoa of the family Triaenophoridae. Discussed are interspecific similarities and differences between the spermatozoa of the two Eubothrium species as well as between these and other Eucestoda.

ami1, an Orthologue of the Aspergillus nidulans apsA Gene, Is Involved in Nuclear Migration Events Throughout the Life Cycle of Podospora anserina

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 633-646
Author(s):  
Fatima Graïa ◽  
Véronique Berteaux-Lecellier ◽  
Denise Zickler ◽  
Marguerite Picard
Keyword(s):  
Aspergillus Nidulans ◽  
Nuclear Migration ◽  
Structural Features ◽  
Podospora Anserina ◽  
Mating Types ◽  
Male Sterile ◽  
Male Gametes ◽  
Functional Differences ◽  
Abnormal Distribution ◽  
Null Mutants

Abstract The Podospora anserina ami1-1 mutant was identified as a male-sterile strain. Microconidia (which act as male gametes) form, but are anucleate. Paraphysae from the perithecium beaks are also anucleate when ami1-1 is used as the female partner in a cross. Furthermore, in crosses heterozygous for ami1-1, some crozier cells are uninucleate rather than binucleate. In addition to these nuclear migration defects, which occur at the transition between syncytial and cellular states, ami1-1 causes abnormal distribution of the nuclei in both mycelial filaments and asci. Finally, an ami1-1 strain bearing information for both mating types is unable to self-fertilize. The ami1 gene is an orthologue of the Aspergillus nidulans apsA gene, which controls nuclear positioning in filaments and during conidiogenesis (at the syncytial/cellular transition). The ApsA and AMI1 proteins display 42% identity and share structural features. The apsA gene complements some ami1-1 defects: it increases the percentage of nucleate microconidia and restores self-fertility in an ami1-1 mat+ (mat−) strain. The latter effect is puzzling, since in apsA null mutants sexual reproduction is quite normal. The functional differences between the two genes are discussed with respect to their possible history in these two fungi, which are very distant in terms of evolution.

scholarly journals Sperm ultrastructure in Culmenella rezvoji (Lindholm, 1929) (Gastropoda: Hygrophila)

2019 ◽  
Vol 29 (3) ◽  
pp. 161-170
Author(s):  
E. V. Soldatenko ◽  
A. B. Shatrov ◽  
A. A. Petrov ◽  
T. Ya. Sitnikova
Keyword(s):  
General Pattern ◽  
Far East ◽  
Taxonomic Position ◽  
Thin Filaments ◽  
High Profile ◽  
Transmission Electron ◽  
Mitochondrial Derivative ◽  
Sperm Characters ◽  
Narrow Ridge ◽  
Electron Lucent

The taxonomic position of the genus within Hygrophila remains uncertain. The spermatozoa of , a species from the Far East of Russia, were examined using a combination of light, scanning and transmission electron microscopy with the objective to assess the utility of sperm characters for clarifying the phylogenetic relationships of the genus. The spermatozoa of C. rezvoji are divided into four regions: head, midpiece, glycogen piece and endpiece. The head contains a slender, cone-shaped acrosome and a conical nucleus with a sinistrally coiled keel. The acrosome consists of an apical vesicle and a thick-walled pedestal with an electron lucent canal partially filled with a patchy electron-dense material. The midpiece contains the mitochondrial derivative that encloses apically three parallel glycogen-filled tracts (helices) positioned in such a way that in the sperm cross section two helices lie opposite each other and equidistant from the third helix. The surface of the sperm above one of the helices forms a high, narrow ridge; the ridges above the remaining two helices have a much lower profile. The boundary between the midpiece and glycogen piece is demarcated by a constriction (annulus) consisting of an anterior electron-dense ring and a posterior conical cylinder connected to the ring with thin filaments. The structure of spermatozoa in Culmenella is consistent with the general pattern of sperm morphology common to all studied species of Hygrophila, but the spermatozoa of Culmenella also have distinctive characters (three glycogen helices and high-profile surface ridge in the apical portion of the midpiece) that should be potentially useful in resolving the taxonomic position of this genus.

scholarly journals Morphology and Physiology of Gamete Mating and Gamete Fusion in the Fungus Allomyces

1982 ◽  
Vol 53 (1) ◽  
pp. 193-209
Author(s):  
JEFFREY POMMERVILLE
Keyword(s):  
Plasma Membrane ◽  
Protein Interactions ◽  
Divalent Cations ◽  
Freeze Fracture ◽  
Young Male ◽  
Structural Features ◽  
Posterior Region ◽  
Gamete Fusion ◽  
Male Gametes ◽  
Time Required

New structural features of gametes are presented and several physiological aspects of mating and gamete fusion in the fungus Allomyces macrogynus are described. In the posterior region of the male gametes, where fusion is thought to occur, thin-section electron microscopy demonstrated the presence of microfilaments that were associated with a ruffling of the otherwise smooth plasma membrane. When the cells were treated with the microfilament-disruptive drug cytochalasin B, fusion was inhibited due to the interaction of the drug with the female gamete. Freeze-fracture replica analysis of the posterior region of the gamete plasma membrane showed an area devoid of membrane particles (termed the flagellar collar) at the basal end of the flagellum. Physiological analysis of gamete mating and fusion showed a requirement for divalent cations, and the time required for gamete mating could be lengthened or shortened by decreasing or increasing, respectively, the divalent cation concentration. Diphenhydramine and chloroquine also increased the time required for mating or completely prevented fusion. Tertiary amine local anaesthetics produced the same type of results, as did trypsin and Pronase. Phospholipases were without an inhibitory effect. When the gametes were washed free of the drugs prior to mating, it was seen that the female gametes were more sensitive to cell surface changes than the males. In addition, 2-h-old female gametes showed a 70% loss of fusion ability with young male gametes while the reverse experiment showed only a 20% decrease. These observations support the concept that gamete mating and fusion may occur at the flagellar collar area and that mating in A. macrogynus is governed, at least in part, by cation and protein interactions.

Riders on the sperm: sperm dimorphism and spermatozeugmata in nematodes from the genus Steinernema (Rhabditida: Steinernematidae)

Nematology ◽  
2007 ◽  
Vol 9 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Sergei Spiridonov ◽  
Mutsuhiro Yoshida ◽  
Vladimir Yushin
Keyword(s):  
Gap Junctions ◽  
Nuclear Envelope ◽  
Ultrastructural Study ◽  
Entomopathogenic Nematodes ◽  
Size Difference ◽  
Male Gametes ◽  
Motile Cells ◽  
Basic Set ◽  
Sperm Dimorphism ◽  
Mature Spermatozoa

AbstractA comparative ultrastructural study of the male gametes in entomopathogenic nematodes of the genus Steinernema (Rhabditida: Steinernematidae) is based on two species producing monomorphic (S. feltiae) and dimorphic (S. tami) spermatozoa. The spermatozoa of both species are basically the same as in many other Rhabditida. Immature spermatozoa from the testis are unpolarised cells containing a nucleus without a nuclear envelope, mitochondria and membranous organelles (MO), a unique component of the nematode spermatozoa. Mature spermatozoa have a nucleus, mitochondria and emptied MO, each attached to a sperm plasmalemma and opening to the exterior via a pore. Monomorphic mature spermatozoa of S. feltiae are 5 μm in diam., bear pseudopods, and form chains of several cells joined by gap junctions. The dimorphic immature spermatozoa of S. tami form spermatozeugmata where the single giant megaspermatozoon (30-35 μm diam.) bears numerous tiny, 3 μm microspermatozoa, intimately attached to the megaspermatozoon surface by gap junctions. Mature megaspermatozoa from the uterus are motile cells 35-50 μm diam.; they have prominent pseudopods and convey immotile, 2 μm microspermatozoa towards the oviduct. Unlike many other invertebrates, sperm dimorphism in S. tami does not change the basic set and structure of organelles, only their number. The genus Steinernema has two strategies for sperm agglomeration: i) chains of monomorphic spermatozoa of normal size, as in S. feltiae; and ii) spermatozeugmata based on a dramatic size difference between spermatozoa formed in the testis, as exemplified by S. tami. According to the types of sperm agglomeration, the genus Steinernema is divided into two main clades.

Ultrastructure of spermiogenesis and mature spermatozoon of Angularella beema (Clerc, 1906) (Cestoda, Cyclophyllidea, Dilepididae)

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Aneta Yoneva ◽  
Jordi Miquel ◽  
Zdzisław Świderski ◽  
Katia Georgieva ◽  
Yana Mizinska ◽  
...  
Keyword(s):  
Mature Spermatozoon ◽  
Cortical Microtubules ◽  
Cestode Species ◽  
Family Presence ◽  
Differentiation Zone ◽  
Type Iv ◽  
The Family ◽  
Cytoplasmic Protrusion ◽  
Ultrastructural Characteristics ◽  
First Time

AbstractThe ultrastructure of the spermiogenesis of a dilepidid cestode species is described for the first time. The spermiogenesis of Angularella beema is characterised by absence of both flagellar rotation and proximodistal fusion. The differentiation zone is surrounded by cortical microtubules and is delimited by a ring of arching membranes. It contains two centrioles, one of which develops the axoneme that grows directly into the elongating cytoplasmic protrusion. This pattern of spermiogenesis was described as the Type IV spermiogenesis of cestodes. Among cestodes, similar pattern of spermiogenesis is known in the family Hymenolepididae and in some representatives of the family Anoplocephalidae. The mature spermatozoon of A. beema consists of five regions differing in their ultrastructural characteristics. It is characterised by the presence of cortical microtubules (spirally arranged at angle of 30–40° to the spermatozoon axis) and a single crested body. There is a periaxonemal sheath in certain parts of the spermatozoon as well as glycogen-like granules between the periaxonemal sheath and the cortical microtubules. The comparisons of the mature spermatozoon of A. beema with those of other two dilepidid species (Dilepis undula and Molluscotaenia crassiscolex) demonstrate some variation within the family: presence of periaxonemal sheath in A. beema and D. undula and its absence in M. crassiscolex; presence of electron-dense rods in D. undula and their absence in A. beema.

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