Fertilization induced changes in sea urchin sperm: mitochondrial deformation and phosphatidylserine exposure

This study demonstrates that the single mitochondrion of the sea urchin sperm undergoes a shape change at fertilization that is linked to respiration. The mitochondrion swells and shifts to the lateral side of the sperm head on contact with the homologous egg jelly or egg surface; Mg(2+)- or Na(+)-free seawater or respiratory inhibitors also induce this change. During the mitochondrial deformation, the sperm decreases the rate of oxygen consumption and their redox-state of cytochromes is disrupted b-c(1)/c. Simultaneously, the adenine nucleotides content changes precipitously. This suggests that mitochondrial morphology is strongly associated with respiratory activities in the sea urchin sperm. These changes in mitochondrial morphology and function are similar to the mitochondrial changes in apoptotic cells such as swelling, decrease in its membrane potential, and release of cytochrome c. In apoptotic cells, the exposure of phosphatidylserine from the inner to outer leaflet of the plasma membrane is one of prominence phenomena. This change was visualized by staining the sea urchin sperm with Annexin V-Fluorescein. It is possible that mitochondrial deformation is an initial sign of sperm destruction, which like as apoptotic cells.     

Functional anatomy of the secondary copulatory apparatus of the male dragonfly Tramea virginia (Odonata: Anisoptera)

In the dragonfly Tramea virginia, the secondary copularoty apparatus (SCA) on the venter of the second and third abdominal segments consists of the anterior and posterior laminae, a pair of gential lobes and hamules, the ligula, genital fossa, supporting frame work, and the four segmented, highly specialized penis. The penis head represnts the distal or fourth segment of the penis and bears paired lateral and apical lobes and a medial process. The medial process includes a sperm reservior, a short sperm tube, and paired cornua and inner lobes. The sperm reservoir opens into the sperm tube which bears a terminal orifice between the inner lobes. Gross morphology of the SCA of T. virginia is similar to that of other libellulids except that the gential lobes and hamules are comparatively large in size, the ligula is triangular in shape with an apical flat rectangular lobe and stiff basal setae, the penis bears a pair of cuticular denticles below the spur of the second segment, the apical lobes are inflatable without spines and bristles, and the cornua with smooth outer and spiny inner surface collectively signifying the species-specific anatomical features and the functional specialization for sperm transfer and removal. © 1993 Wiley-Liss, Inc.     

Ultrastructure of the sperm and spermatogenesis and spermiogenesis of Dina lineata (hirudinea,erpobdellidae)

The mature sperm of Dina lineata is of the modified type. The sperm are 48 μm long and 0.3 μm wide. The sperm are filiform and helicoidal cells with a distinct head, a midpiece, and a tail. There are two distinct regions in the head: the acrosome and the posterior acrosome, each with its own characteristic morphology. The midpiece is the mitochondrial region and has a single mitochondrion. Two distinct portions can be observed in the tail: the axonematic region and the terminal piece. In the process of spermatogenesis the early spermatogonia divide to form a poliplast of 512 spermatic cells. In the spermiogenesis the following sequential stages can be distinguished: elongation of the flagellum; reciprocal migration of mitochondria and Golgi complex; condensation of chromatin and formation of the posterior acrosome; spiralization of nuclear and mitochondrial regions; and, finally, formation of the anterior acrosome. The extreme morphological complexity of the Dina spermatozoon is related to the peculiar hypodermal fertilization which characterizes the erpobdellid family. Correlation between sperm morphology and fertilization biology in the Annelida is revised.     

Comparative Morphology of Echinoderm Sperm and Possible Phylogenetic Implications

The sperm morphology of at least 7 crinoids, 11 ophiuroids,23 asteroids, 23 holothuroids, and 37 echinoids is known. Forall the known crinoids, ophiuroids, and asteroids, the spermare spherical, while those of echinoids are conical. Holothuroidsperm are basically spherical, with two exceptions: cylindricalin Cucumaria lubrica and tabloid in Cucumaria pseudocurata.The possible implications of sperm morphology in the mode offertilization and in echinoderm phylogeny are discussed.     

Morphological aspects of fertilization in Phallusia (Ascidia) nigra (Ascidiacea,Tunicata)

The spermatozoa of Phallusia (Ascidia) nigra have an elongated head (approximately 5 m in length) in which a nucleus and a single mitochondrion are located side by side. There is no midpiece. The apex of the head is wedge-shaped. Acrosomal vesicles (approximately 55–65 nm in diameter) and moderately electron-dense material (MEDM) are present between the plasmalemma and the nuclear membranes in the anterior tip of the head. The MEDM occupies a central position and three or four acrosomal vesicles are seen in a line alongside it. The acrosomal vesicles disappear as the sperm makes contact with the surface of the chorion. Gamete fusion most likely occurs between a small process extending from the peripheral margin of the sperm apex and the egg surface, resulting in incorporation of the sperm into the egg from the anterior region of its head.     

Morphology of gametes in sea urchins from Peter The Great Bay,Sea of Japan

The fine structure of the gametes in six sea urchin species of the Sea of Japan was studied. The sperm in Strongylocentrotus nudus, S. intermedius, Echinocardium cordatum, Scaphechinus mirabilis, Sc. griseus and Echinarachnius parma are species-specific. The conical head and symmetrically disposed ring-shape mitochondrion are common to regular sea urchin sperm cells. S. nudus is characterized by the bulb-shaped head of the sperm; S. intermedius, by a bullet-shaped one. The sperm spearhead and small amount of post-acrosome material are common to irregular sea urchins; the sperm width: length ratio varies for different species, with the highest for Sc. mirabilis. The sperm of Sc. griseus is characterized by two lipid drops in the middle part of sperm. Asymmetrical mitochondrion disposal is usual for E. parma. Actin filaments are found in the postacrosome material in the sperm of heart-shaped sea urchins. The differences in the fine structure of sperm in cosmopolitan species Ech. cordatum inhabiting the Sea of Japan and coastal areas of the Northeast Atlantic may bear record to the complex existence of species Ech. cordatum. The fine structure of sperm is unique for each of the studied families, Strongylocentrotidae, Scutellidae, and Loveniidae. The eggs of all the species are characterized by vitelline and jelly-like membranes. The vitelline membrane is formed by cytoplasm protrusions; the area between them is filled with fibrillar material. The jelly-like membrane is formed by fibrillar material associated with apical parts of microvilli of the vitelline membrane. The irregular sea urchins Sc. griseus, Sc. mirabilis and E. parma are characterized by chromatophores situated in the jelly-like membrane, with the highest abundance in Sc. mirabilis.     

The sperm of Hexagenia (Pseudeatonica) albivitta Walker (Ephemeroptera: Fossoriae: Ephemeridae)

This study describes the sperm morphology of the mayfly Hexagenia (Pseudeatonica) albivitta (Ephemeroptera). Its spermatozoon measures approximately 30 μm of which 9 μm corresponds to the head. The head is composed of an approximately round acrosomal vesicle and a cylindrical nucleus. The nucleus has two concavities, one in the anterior tip, where the acrosomal vesicle is inserted and a deeper one at its base, where the flagellum components are inserted. The flagellum is composed of an axoneme, a mitochondrion and a dense rod adjacent to the mitochondrion. A centriolar adjunct is also observed surrounding the axoneme in the initial portion of the flagellum and extends along the flagellum for at least 2 μm, surrounding the axoneme in a half‐moon shape. The axoneme is the longest component of the flagellum, and it follows the 9+9+0 pattern, with no central pair of microtubules. At the posterior region of the flagellum, the mitochondrion has a dumb‐bell shape in cross sections that, together with the rectangular mitochondrial‐associated rod, is responsible for the flattened shape of the flagellum. An internal membrane is observed surrounding both mitochondrion and its associated structure.     

Functional association between female sperm storage organs and male sperm removal organs in calopterygid damselflies

Female damselflies in the family Calopterygidae have two sperm storage organs: a spherical bursa copulatrix and a tubular spermatheca. Male flies have a peculiar aedeagus with a recurved head with which to remove bursal sperm, and lateral spiny processes to remove spermathecal sperm. The lateral processes differ among species and populations in terms of their width relative to the spermathecal duct: the narrower processes are physically able to access spermathecal sperm, while the wider ones are not. In the present study, sperm storage patterns and aedeagal structures were compared between two calopterygid species with different spermathecal structures –Calopteryx cornelia and Mnais pruinosa– with respect to not only sperm quantity (number) but also sperm quality (viability), by using a recently developed method based on live/dead dual fluorescence. Calopteryx cornelia is a typical spermathecal sperm remover. In this species, viability was similar between bursal and spermathecal sperm. In contrast, in M. pruinosa, the spermatheca was much smaller than the bursa and often contained no sperm. Even when the spermatheca of this species did contain sperm, a high percentage of it was dead. Although the spermatheca of M. pruinosa has such atrophic tendencies, males have nevertheless developed long and spiny lateral processes similar to those of C. cornelia, suggesting the processes have functions other than spermathecal sperm removal. They possibly function as stoppers or guides for manipulating the aedeagal head to remove the sperm mass from the bursa.     

Interspecific variation of sperm morphology in the Australian rodent genus Zyzomys

The sperm head morphology and tail length of two species of Australian rock rats, Zyzomys argurus and Zyzomys pedunculatus, are presented. In Z. argurus the sperm head has an apical hook together with two ventral processes extending from the upper concave surface that are largely composed of cytoskeletal material, and the sperm tail is about 135 µm in length. By contrast, in Z. pedunculatus the sperm head is paddle‐shaped with the nucleus capped by an acrosome that has a large apical segment and is surrounded by a thin layer of cytoskeletal material, and the sperm tail is only around 85 µm in length. Since the structure of the spermatozoon of Z. argurus is similar to that of most of the old endemic Australian rodents it is presumed to be the ancestral condition within the Zyzomys genus with that of Z. pedunculatus being highly derived and showing convergence with the sperm structure in some other orders of mammals.     

Ascidian sperm penetration and the translocation of a cell surface glycosidase

Sperm bind to vitelline coat (VC) glycosides of ascidian eggs by means of a sperm surface glycosidase (Hoshi et al.: Zool Sci 2:65, 1985). In the genus Ascidia, N-acetylglucosamine (NAG) is the VC ligand. After initial binding by the tip of the head, sperm pass through the VC and perivitelline space leaving the single mitochondrion outside. This process can also be followed in vitro on a coverslip. Analysis of recorded video images shows that the sperm moves away from the anchored mitochondrion. Our model for sperm penetration suggests that mitochondrial translocation is responsible for driving the sperm into the egg. In the work presented here, we have demonstrated that ascidian sperm have N-acetyl-beta-D-glucosaminidase (NAGase) activity with an acidic pH optimum. This enzyme, which can be removed from the sperm with Triton X-100, binds to concanavalin A, demonstrating that it is glycosylated. Histochemical methods disclose that the enzyme is originally located at the tip of the head but subsequently remains with the surface overlying the mitochondrion during translocation. Fluorescent Con A was used as a second label for localization of the enzyme on the cell surface during translocation. Colocalization of both probes of the enzyme support a crucial facet of our model; the sperm surface VC binding site remains over the mitochondrion during translocation. This would couple mitochondrial translocation with sperm penetration and drive the sperm into the egg.     

Differences in sperm morphology in foam‐nesting leptodactyline frogs (Anura,Leptodactylidae)

Sperm morphology is diverse among vertebrates and is influenced by the reproductive strategies adopted by species. In anurans, sperm morphology is associated with reproductive modes and mating systems. Here, we describe the sperm morphology of 11 frog species in the genus Leptodactylus and that of Lithodytes lineatus and discuss the relationship between sperm morphology and species' mating systems. We observed two distinct sperm morphotypes among the leptodactyline species, which differed mostly in head morphology. Type I sperm had triangular head, discrete acrosome vesicle with posterior margin not clearly visible; type II sperm had elongated head, clear acrosomal vesicle with posterior margin clearly visible. These sperm types do not seem to be associated with phylogeny; instead, type II sperm was observed in all polyandrous species analysed and in species with evidences of polyandry. Moreover, sperm of all species presented tail with undulating membrane connected to the axial fibre. We suggest that differences in sperm morphology might be associated with sperm competition to what polyandrous species are subjected. However, natural history observations on polyandrous mating in some species presenting type II sperm and phylogenetic comparative studies are need to elucidate the role of mating systems in the evolution of sperm morphology in leptodactylines.     

The spermatozoon of the Old Endemic Australo‐Papuan and Philippine rodents – its morphological diversity and evolution

Breed, W.G. and Leigh, C.M. 2010. The spermatozoon of the Old Endemic Australo‐Papuan and Philippine rodents – its morphological diversity and evolution.—Acta Zoologica (Stockholm) 91 : 279–294 The spermatozoon of most murine rodents contains a head in which there is a characteristic apical hook, whereas most old endemic Australian murines, which are part of a broader group of species that also occur in New Guinea and the Philippines, have a far more complex sperm form with two additional ventral processes. Here we ask the question: what is the sperm morphology of the New Guinea and Philippines species and what are the trends in evolutionary changes of sperm form within this group? The results show that, within New Guinea, most species have a highly complex sperm morphology like the Australian rodents, but within the Pogonomys Division some species have a simpler sperm morphology with no ventral processes. Amongst the Philippines species, many have a sperm head with a single apical hook, but in three Apomys species the sperm head contains two additional small ventral processes, with two others having cockle‐shaped sperm heads. When these findings are plotted on a molecular phylogeny, the results suggest that independent and convergent evolution of highly complex sperm heads containing two ventral processes has evolved in several separate lineages. These accessory structures may support the sperm head apical hook during egg coat penetration.     

Interspecific Variation in Structural Organisation of the Spermatozoon in the Asian Bandicoot Rats,Bandicota Species (family Muridae)

The structural organisation of the spermatozoon from two species of bandicoot rats Bandicota bengalensis and Bandicota indica was investigated by light and electron microscopy together with the effect of incubation in Triton-X 100 and sodium dodecyl sulphate. The sperm head of B. bengalensis is invariably falciform, has a uniform electron-dense nucleus capped by an acrosome with a posteriolateral equatorial segment, a subacrosomal cytoskeleton with a large rostral perforatorium, and a sperm tail, attached to the lower concave surface of the sperm head, with typical coarse fibres and fibrous sheath. By contrast, the sperm head shapes of B. indica are generally conical or bulbous, the nucleus contains a few large vacuoles, the acrosome lacks an equatorial segment, no recognisable perforatorium occurs, and the sperm tail, which is attached basally, is very short with only modest development of coarse fibres and fibrous sheath. These results indicate that, within the genus Bandicota, huge interspecific differences in morphology of the spermatozoon have evolved. The spermatozoa of B. bengalensis are similar to those of Rattus and many other murids and thus presumably represent the ancestral condition, whereas those of B. indica (and B. savilei) are unlike spermatozoa from any other eutherian mammal so far described. © 1998 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd. All rights reserved     

On the morphology of spermatozoa in some African murines (Rodentia, Muridae): the taxonomic and phylogenetic aspects

A comparative analysis of sperm-head morphology and measurements in 17 species from nine genera of African Murinae: Rattus rattus, Mastomys coucha, M. huberti, M. erythroleucus, Mastomys sp. 2, Praomys albipes, P. fumatus, Mus mahomet, Arvicanthis somalicus, A. abyssinicus, A. dembeensis, Arvicanthis sp., Lemniscomys macculus, Pelomys harringtoni, Acomys cahirinus, Acomys sp., Uranomys ruddi, was carried out. Spermatozoa of all examined species are of the same basic type. They consist of an asymmetrical head, falciform or scythelike in shape, and a tail attached to the ventrocaudal surface of the head. There are great interspecific differences in sperm morphology and size. The significance of this variation for estimation of taxonomic aspects and phylogenetic relationships among the species, as well as between them and other groups, is discussed. The sperm morphology supports a close evolutionary relationship among the genera Lemniscomys and Arvicanthis. It also indicates that Pelomys is distinctive. The relationships between Acomys and Uranomys are discussed.     

Unusual structures in the spermatozoa of the ascidians Lissoclinum perforatum and Diplosoma listerianum (Didemnidae)

Summary Sperm and spermiogenesis of L. perforatum and D. listerianum have been investigated by light- and electron microscopy. The study revealed basic ascidian organization of sperm cells with the nucleus flanked by a unique mitochondrion, but with specializations not previously reported: a dense groove on the head surface, extended nucleus-mitochondrion association, and well developed endoplasmic derivatives.The groove is a long furrow of the plasmalemma stretching the nucleus towards the cell periphery. At least two parallel, 20 nm high, ridges emerge from the bottom of the groove. At the opposite side of the groove the long mitochondrion embraces the nucleus by extending its outer membrane over the nuclear envelope; a restricted cytoplasmic space is always found between the two organelles. Filamentous inclusions organized in two strands are present in the mitochondrial matrix. Endoplasmic derivatives appear as a single, extended cistern in L. perforatum, and series of long tubules in D. listerianum. They appear to originate in the spermatid from the Golgi complex and endoplasmic reticulum. The spermatozoon lacks an evident acrosomal complex, but the possible homology of small apical densities with an acrosomal complex is considered. It is suggested that the functional role of these specialized structures is related to the special mode of internal fertilization of these species.     

Giant,accordioned sperm acrosomes of the greater bulldog bat,Noctilio leporinus

Sperm of the greater bulldog bat Noctilio leporinus display an architecture that is totally unique among mammalian spermatozoa. The sperm head of Noctilio is extraordinarily large and flat and lies eccentrically with respect to the sperm tail. The major portion of the atypically large acrosome lies anterior to the nucleus and is shaped into a dozen accordionlike folds that run parallel to the long axis of the sperm. The ridge of each fold is shaped into ∼60 minute, evenly spaced rises that extend along the entire length of the fold. We speculate that acrosome ridges may serve to strengthen the sperm head during transport. Mol. Reprod. Dev. 48:90–94, 1997 © 1997 Wiley-Liss, Inc.     

THE EARLY RADIATION AND PHYLOGENY OF ECHINODERMS

1. Living echinoderms are characterized by an extensive water vascular system developed from the larval left hydrocoel, a complex, multi-plated endoskeleton with stereom structure, and pentamery. Fossil evidence shows that stereom evolved before pentamery, but both were acquired during the Lower Cambrian. 2. Cladistic analysis of Lower Cambrian genera reveals very few characters in common between carpoids and true echinoderms, and that the split between them was the first fundamental evolutionary dichotomy within the Dexiothetica. 3. Helicoplacoids are stem group echinoderms with spiral plating and three ambulacra arranged radially around a lateral mouth. They are the most primitive echinoderms and the first to show a radial arrangement of the water vascular and ambulacral systems. Unlike later echinoderms, their skeleton shows no dorsal/ventral (aboral/oral) differentiation. They were probably sedentary suspension feeders. 4. Camptostroma is the most primitive known pentaradiate echinoderm and, in our view, possibly a common ancestor of all living groups. It had a short conical dorsal (aboral) surface with imbricate plating, a ridged lateral wall and a slightly domed ventral (oral) surface with five curved ambulacra in a 2-1-2 arrangement inherited from the triradiate pattern of the helicoplacoids. Interambulacral areas bore epispires and the CD interambulacrum contained the anus, hydropore and/or gonopore. All parts of the theca had plates in at least two layers. 5. All other echinoderms belong to one of two monophyletic subphyla, the Pelmatozoa and the Eleutherozoa. 6. Stromatocystites is the earliest known eleutherozoan and differs from Camptostroma in having a test with only one layer of plates and having lost the dorsal elongation. In Stromatocystites the dorsal surface is flat and the plating tesselate. Stromatocystites was an unattached, low-level suspension feeder. 7. The lepidocystoids are the earliest known pelmatozoans. They differ from Camptostroma in having an attached dorsal stalk which retained the primitive imbricate plating, and by developing erect feeding structures along the ambulacra. In Kinzercystis, the ambulacra are confined to the thecal surface and erect, biserial brachioles arise alternately on either side. Lepidocystis has a similar arrangement except that, the distal part of each ambulacrum extends beyond the edge of the theca as a free arm. 8. Pelmatozoans diverged more or less immediately into crinoids, with multiple free arms composed of uniserial plates, and cystoids sensu lato, which retained brachioles. Gogia (Lower to Middle Cambrian) is the most primitive known cystoid and differs from Kinzercystis principally in having all plating tesselate, while Echmatocrinus (Middle Cambrian) is the most primitive known crinoid and differs from Lepidocystis in lacking brachioles and in having more than five free arms with uniserial plates. 9. Post Lower Cambrian differentiation of pelmatozoan groups proceeded rapidly, exploiting the primitive suspension-feeding mode of life. Maximum morphological diversity was reached in the Ordovician, but thereafter crinoids progressively displaced cystoid groups and reached their peak diversity during the Carboniferous. The eleutherozoans were slower to diversify, but by the Arenig the earliest ‘sea-stars’ (in reality, advanced members of the eleutherozoan stem group) had reversed their living orientation and had begun to exploit a deposit-feeding mode of life. These in turn led to the ophiuroids, echinoids and holothuroids. 10. The basic echinoderm ambulacrum was already present in the helicoplacoids. It had biserial, alternate flooring plates and complexly plated sheets of cover plates on either side. The radial water vessel lay in the floor of the ambulacrum, external to the body cavity, and gave rise ventrally to short, lateral branches (fore-runners of tube feet) that were used to open the cover plate sheets, and dorsally was connected to internal compensation sacs which acted as fluid reservoirs (and were preadapted for a role in gaseous exchange). Plating on the cover plate sheets was organized and reflected the positions of the lateral branches from the radial water vessel. In Camptostroma, the cover plate sheets had biserially aligned rows of cover plates associated with the lateral branches. 11. Brachioles arose by extension of the lateral branches of the radial water vessel and associated serially aligned cover plates found in Camptostroma. They bear a single alternate series of cover plates. In Lepidocystis the ambulacra extended beyond the edge of the oral surface as true arms. Brachial plates of arms are homologues of primary ambulacral flooring plates, and arms bear multiple series of cover plates. Uniserial ambulacral plating is a derived condition and evolved independently in crinoids, paracrinoids and isorophid edrioasteroids. Pinnules in crinoids arose independently in inadunates and camerates by a progressively more unequal branching of the arms. Thus all parts of the subvective system in crinoids are internally homologous, whereas in cystoids, brachioles and arms (or ambulacra) are not homologous structures. 12. The position of the hydropore is the best reference point in orientating echinoderms. Carpenter's system of identifying ambulacra by letters, arranged clock-wise in oral view with the A ambulacrum opposite the hydropore, is consistent in all echinoderm classes. In all Lower Cambrian pentaradiate echinoderms the anus, gonopore and hydropore lie in the CD interambulacrum and this is accepted as the primitive arrangement. In helicoplacoids we tentatively suggest that the A ambulacrum spiralled down from the mouth while the two ambulacra that spiralled up represent the B + C and D + E ambulacra combined. 13. The pelmatozoan stem arose from a polyplated stalk, via a meric stem to a true column with holomeric (single piece) columnals. This happened independently in the crinoids and the cystoids. 14. Our analysis of echinoderm phylogeny leads us to recommend the following changes to the higher level classification of echinoderms: The phylum Echinodermata includes only those groups with radial symmetry superimposed upon a fundamental larval asymmetry. It has a stem group that contains the triradiate helicoplacoids and a crown group to which all other (pentaradiate) echinoderms belong. The crown group contains two monophyletic subphyla, the Pelmatozoa and the Eleutherozoa, and the Pelmatozoa contains two superclasses, the Crinoidea which are extant and the Cystoidea, which are extinct.     

The structure of encysted sperm of some British Pseudoscorpiones (Arachnida)

The sperm of pseudoscorpions consists of a coiled head (nuclear material), axial filament and an "annular" mitochondrion, all enclosed within a cyst.
Variations occur in the gross morphology of different pseudoscorpion sperm. These variations are discussed in terms of possible morphological relationships.     

Rearrangement of the PH-20 protein on the surface of macaque spermatozoa following exposure to anti-PH-20 antibodies or binding to zona pellucida

Capacitated cynomolgus macaque sperm have a surface hyaluronidase (PH-20) that is evenly distributed over the entire head and can be visualized at the ultrastructural level using a secondary antibody labeled with colloidal gold . Exposure of sperm to mono-specific, bivalent polyclonal antibodies to PH-20 causes a rapid clustering of PH-20 . The predominant morphological consequence of PH-20 redistribution is its aggregation along the lateral edge of the sperm head. Monovalent Fab fragments of the anti-PH-20 antibody bound to the sperm head but did not induce a change in PH-20 distribution. PH-20 aggregation was observed in almost all sperm following treatment with the polyclonal antibody, but only about 20% of the sperm had morphological acrosome reactions, regardless of the time of exposure or the concentration of antibody. There was morphological evidence of swelling of the acrosomal matrix in over 50% of the sperm following exposure to anti-PH-20 antibodies. Anti-PH-20 Fab fragments did not induce the acrosome reaction or acrosomal matrix swelling. Sperm bound to macaque zona pellucida also showed aggregation of the PH-20 protein as soon as 30 sec after sperm-zona interaction. This aggregation was not observed when macaque sperm were bound to hamster zona pellucida. When macaque sperm were surface-labeled with biotin and then incubated with anti-PH-20 antibodies or macaque zona pellucida, there was no evidence of a global surface protein rearrangement, although PH-20 protein was aggregated on the surface of the same sperm cells. An increase in levels of internal sperm Ca⁺⁺ was measured in association with the antibody-induced PH-20 aggregation. Fab fragments did not increase Ca⁺⁺ levels, but when they were crosslinked with anti-Fab antibody there was a significant Ca⁺⁺ increase and induction of acrosome reactions. Anti-PH-20 Fab fragments did not block macaque sperm binding to macaque zona pellucida or the zona-induced acrosome reaction. We conclude that PH-20 on the sperm surface is involved in sperm-zona pellucida interaction and the zona-induced acrosome reaction. Mol. Reprod. Dev. 50:207–220, 1998. © 1998 Wiley-Liss, Inc.     

Ultrastructure and functional morphology of male genital organs and spermatophore formation inProtodrilus (Polychaeta,Annelida)

Summary The structure and functional morphology of lateral organs and sperm ducts, as well as the mechanisms of spermatophore formation and transfer, are investigated by means of light and electron microscopy in the genusProtodrilus. The sperm ducts are simple, ciliated, intercellular gonoducts with a funnel section surrounded by a thin muscle layer and a tube section opening externally in the anterior region of the lateral organs. No glands are present in the sperm ducts. The lateral organs are formed by long epidermal invaginations enclosing an elongate lumen into which numerous cilia project and a large number of glands open. Five to ten different gland types with strikingly distinctive secretory granules are found in the different species. In addition, special supporting cells, the so-called sponge cells, sensory cells and an underlying nervous tissue are developed in the lateral organs. It is stated that apart from some similarities to the ventral atrium ofNerilla antennata no corresponding organs are known within the Annelida. It is argued that inProtodrilus the spermatophores are formed by the lateral organs as there are a high number of glands opening into the lumen of the organ. The possible origin and genesis of the male gonoducts as well as the mode of spermatophore transfer inProtodrilus is discussed.Abbreviations used in the figures bl basal lamina - cc coelomic cell - ci ciliated cell - cir ciliary root - cr ciliary ring - cu cuticle - cv bs contractile ventral blood sinus - d dissepiment/septum - dbs dorsal blood sinus - es euspermatozoa - f funnel - fi filament - g gut - glo gland openings - lgl lateral organ gland - lm longitudinal muscle - lo lateral organ - lu lumen - mi mitochondrion - mt microtubules - mu muscle - mv microvilli - mvc microvillar crown - n nucleus - ne nervous tissue - o opening - ps paraspermatozoa - rer rough endoplasmatic reticulum - s spermatozoa - sc sponge cell - sg salivary gland - spd sperm duct - spdo sperm duct opening - t tube - tm transverse muscle - vc ventral ciliary band