Boar sperm membranes antigens. II. Reorganization of an integral membrane antigen during capacitation and acrosome reaction

The dynamics of the cell surface during the process of capacitation is impressively shown by means of a monoclonal antibody directed against the P86/5 antigen. This glycoprotein was located in the sperm plasma membrane using the colloidal gold method in combination with specimen preparation in toto. The antigen is absent at the rostral tip of non-capacitated spermatozoa, but forms clusters over the principal segment and the equatorial segment after induction of capacitation. This formation of microdomains with different properties may be a prerequisite for the onset of the acrosome reaction (AR). During AR the diffusion barrier for the P86/5 antigen breakes down and the antigen occupies now the rostral crescent-like area of the sperm head. These observations are discussed with respect to zona binding and induction of the AR in boar spermatozoa.

Boar sperm membranes antigens. I. Topography of a mobile glycoprotein of the sperm cell membrane

A monoclonal antibody, designated mAb P86/5, was generated by immunization of female Balb/c mice with a membrane vesicle fraction composed of the outer acrosomal membrane and plasma membrane (PM-OAM). As determined by fluorescence microscopy and electron microscopy P86/5 recognizes a sperm plasma membrane antigen that is restricted to the sperm head. In intact spermatozoa the P86/5-antigen is distributed over the surface of the sperm head with the exception of the rostral region. By comparing the antibody binding pattern generated at 4 degrees C and 25 degrees C, it could be shown that the P86/5-antigen is capable to diffuse freely within the cell membrane overlying the acrosome whereas its lateral mobility is restricted to the post-acrosomal region. The P86/5-antigen had a molecular weight of about 78 kDa as revealed by SDS-PAGE and western blotting. The glycoprotein nature of the P86/5-antigen was established by lectin affinity chromatography.

Characterization of an acrosomal matrix protein in hamster and bovine spermatids and spermatozoa

Experiments have been carried out characterizing an Mr 22,000 protein present in the acrosomes of hamster and bull spermatozoa. The Mr 22,000 protein is resistant to solubilization in detergent solutions containing high or low salt and has a pI of -5.2. With various lectins, the protein from hamster sperm was shown to be sparingly glycosylated with N-acetylglucosamine, mannose, and galactose while that from the bull demonstrated a slight reactivity for galactose. Using a specific monoclonal antibody (MAB 4/18), the Mr 22,000 polypeptide has been localized exclusively to the acrosomes of mature testicular and epididymal hamster and bovine sperm. Acrosomal components of differentiating bovine and hamster spermatids in tissue sections did not react with the monoclonal antibody, although the protein was present in immunoblots of round spermatids. In bovine sperm, MAB 4/18-staining at the ultrastructural level with immunogold-labeled second antibody was present as a reticulum throughout the acrosomal cap and as punctate aggregates in the equatorial segment. In hamster sperm, MAB 4/18-reactivity was present along the periphery of the acrosome in conjunction with matrix components (M1 and M2), as well as along the inner acrosomal membrane. These observations indicate that the acrosomes of bovine and hamster sperm possess an immunologically related Mr 22,000 protein and suggest that differences in MAB 4/18-staining of spermatids and spermatozoa is a result of epitope modification and/or a change in accessibility of the epitope to the antibody probe during the course of spermiogenesis. Based on its localization and solubility properties, we suggest that the Mr 22,000 protein, in conjunction with other polypeptides, forms a structural framework to maintain acrosomal shape and/or compartmentalize acrosomal contents.

Germ cell regulation of Sertoli cell transferrin mRNA levels

Sertoli cells cultured in the presence of germ cells responded by increasing the level of transferrin mRNA 3-fold as determined by solution hybridization and Northern blot analysis. In contrast, the steady state levels of other mRNAs, including sulfated glycoprotein 1 (SGP-1), sulfated glycoprotein 2 (SGP-2), transferrin receptor, regulatory subunit of cAMP dependent protein kinase, and ferritin light chain, were not influenced by coculture with germ cells. The transferrin mRNA stimulatory activity was found in conditioned medium from germ cells but was not associated with germ cell membrane components. The activity was abolished by treatment of the medium with trypsin. Partial characterization and isolation of the protein(s) from conditioned medium indicated that it has an apparent mol wt between 10 and 30 K. Studies using inhibitors of protein and nucleic acid synthesis indicated that the stimulation of transferrin mRNA by germ cell conditioned medium required both transcription and translation. Sertoli cell enriched (germ cell depleted) testes were obtained from male offspring of pregnant females irradiated at the 19th day of gestation. Testicular transferrin mRNA levels from irradiated rats decreased in comparison to levels in the normal rat, whereas SGP-2 mRNA levels were unchanged. These studies demonstrate that germ cell secretions may interact with Sertoli cells to specifically increase the level of transferrin mRNA and that this interaction may be a mechanism by which germ cells regulate the flow of iron across the seminiferous epithelium.

Characterization of rat testicular peritubular myoid cells in culture: alpha-smooth muscle isoactin is a specific differentiation marker

In frozen sections of testes from 20-day-old rats, alpha-smooth muscle (SM) isoactin was prominently immunostained in the peritubular tissue and in vascular walls, but not in areas populated by germinal cells, interstitial cells, or Sertoli cells. Peritubular myoid cell (PMC)-enriched preparations were isolated by two different procedures involving our previously published sequential enzymatic treatment ("conventional peritubular cell [PC]-enriched preparation") and by density-gradient purification of PMC from these preparations. The properties of different populations of PMC in culture were compared with respect to plating efficiency, rates of proliferation, and presence of cytoskeletal proteins. PMC, maintained in culture under defined conditions, contained proteins immunoreactive with monoclonal antibodies against alpha-SM isoactin. This was detected by immunostaining and by Western blots of cell extracts subjected to gel electrophoresis. Neither Sertoli cells, skin fibroblasts, bovine endothelial cells, nor glial cells contained alpha-SM isoactin detectable by the above techniques. We report the ontogeny of alpha-SM isoactin in the peritubular tissue of testes at different stages of gonadal development, and show that it is detectable within 8 days after birth. In addition, we describe immunocytochemical changes that occur during culture in various media of PMC prepared from testes of 20-day-old rats. We compare the use of alpha-SM isoactin as a differentiation marker for PMC with the use of desmin in facilitating the identification of PMC, and in following alterations in phenotype during culture in various culture media. Data presented demonstrate that about 81% of cells in the "conventional PC-enriched preparation," and about 94% of cells in the more purified populations of PMC were positive for alpha-SM isoactin in cells maintained in culture for 18 h after plating. These same PMC also were shown to express vimentin and plasminogen activator inhibitor, type 1. We conclude that alpha-SM isoactin is an excellent specific marker for PMC in seminiferous tubules and in culture.

[The evaluation of fertility characteristics in hens using fluorescence microscopy]

A method for the assessment of fertility in domestic hens is described. Vitelline membranes of fertilized eggs were coloured with fluorochrome DAPI, following which the DNA of sperms on these membranes has been examined with the help of fluorescence microscopy. After insemination with frozen semen there exist significant correlations between the number of sperms on the vitelline membranes on the one hand and 1) fertilization rates; 2) the length of fertile periods. Furthermore, it was observed that with higher numbers of sperms on the membranes, the length of the fertile periods tends to be shorter than with smaller numbers of sperm.

Characterization of membrane-associated actin in boar spermatozoa

Biochemical, immunological, and electron microscopic methods have been used to provide semi-quantitative estimates and to localize actin in membranes of boar spermatozoa. Immunoblots, using a monoclonal antibody raised against actin from chicken gizzard, detected the protein in caput and cauda sperm plasma membranes. Immunoassay indicated that approximately 1% of the total plasma membrane protein was actin. Monomeric actin accounted for more than one-half of the membrane actin. Approximately 30-40% of plasma membrane actin was insoluble in Triton X-100, and approximately 10% of the total actin remained insoluble after treatment with guanidine hydrochloride. The presence of F-actin in sperm plasma membranes and in plasma membrane detergent-insoluble proteins was detected by fluorescence microscopy using the specific probe NBD phallacidin. When S1 myosin subfragments attached to colloidal gold were used to localize F-actin by electron microscopy, the label was restricted to the outer acrosomal membrane of intact epididymal and ejaculated sperm. Filaments appeared in short arrays along the anterior region of the membrane. S1/gold labeled detergent-insoluble plasma membrane fractions but did not label the plasma membrane in intact sperm. Filaments were least prominent in intact caput spermatozoa and most prominent in ejaculated spermatozoa. We conclude that most actin associated with sperm membranes is in monomeric form in boar spermatozoa, but that actin filaments or protofilaments are components of the outer acrosomal membrane. These filaments may also associate with the plasma membrane overlying the acrosome.

Radial density distribution of chromatin: evidence that chromatin fibers have solid centers

Fiber diameter, radial distribution of density, and radius of gyration were determined from scanning transmission electron microscopy (STEM) of unstained, frozen-dried chromatin fibers. Chromatin fibers isolated under physiological conditions (ionic strength, 124 mM) from Thyone briareus sperm (DNA linker length, n = 87 bp) and Necturus maculosus erythrocytes (n = 48 bp) were analyzed by objective image-processing techniques. The mean outer diameters were determined to be 38.0 nm (SD = 3.7 nm; SEM = 0.36 nm) and 31.2 nm (SD = 3.6 nm; SEM = 0.32 nm) for Thyone and Necturus, respectively. These data are inconsistent with the twisted-ribbon and solenoid models, which predict constant diameters of approximately 30 nm, independent of DNA linker length. Calculated radial density distributions of chromatin exhibited relatively uniform density with no central hole, although the 4-nm hole in tobacco mosaic virus (TMV) from the same micrographs was visualized clearly. The existence of density at the center of chromatin fibers is in strong disagreement with the hollow-solenoid and hollow-twisted-ribbon models, which predict central holes of 16 and 9 nm for chromatin of 38 and 31 nm diameter, respectively. The cross-sectional radii of gyration were calculated from the radial density distributions and found to be 13.6 nm for Thyone and 11.1 nm for Necturus, in good agreement with x-ray and neutron scattering. The STEM data do not support the solenoid or twisted-ribbon models for chromatin fiber structure. They do, however, support the double-helical crossed-linker models, which exhibit a strong dependence of fiber diameter upon DNA linker length and have linker DNA at the center.

Higher transfection efficiency of genomic DNA purified with a guanidinium thiocyanate-based procedure

Efficient transfection of eukaryotic cells is dependent on the purity of the transfected genomic DNA. In an attempt to obtain a more reliable method of DNA purification we have modified the widely used protocol of Blin and Stafford to include a treatment with guanidinium thiocyanate. The DNA obtained following the present protocol transfects eukaryotic cells with higher efficiency.

Motion of individual human spermatozoa, both normal and lacking the outer dynein arms, during a continuous temperature rise

The effect of increasing temperature from 22-25 degrees C to 37 degrees C on various motion characteristics of individual normal human spermatozoa and spermatozoa lacking the outer dynein arms (LODA) was studied by using a new automatic microscopic tracking method. It was found that: 1) The curvilinear velocity (Vc, measured between 1-3 sec) of both normal and LODA spermatozoa, fluctuated more or less intensely between spermatozoa; this fluctuation was not thermodependent. 2) The average Vc in the two groups of spermatozoa increased with the rise in temperature at a similar rate (1 micron/sec/degrees C), but LODA spermatozoa had an initial Vc lower than that of normal spermatozoa (12.5 +/- 5.3 microns/sec and 34.2 +/- 8.2 microns/sec, respectively). 3) The profile of the Vc increase associated with the temperature rise was different for the two groups of spermatozoa: for LODA spermatozoa it was linear between 25-37 degrees C, whereas for normal spermatozoa a plateau was reached at about 31 degrees C. 4) Various patterns of trajectory were found for both normal and LODA spermatozoa; these patterns were unrelated to temperature. However, LODA spermatozoa had more linear trajectories than normal spermatozoa. 5) Plots derived from reaction rate theory showed that the activation enthalpy, delta H was a function of the increase of Vc for both normal and LODA spermatozoa, but that delta H was higher for LODA spermatozoa.

[Structure of the chromatin with long linker DNA]

The method of velocity sedimentation have been used to investigate ionic-strength-induced compaction of sea urchin sperm chromatin characterized by extremely long linker DNA (100 b.p.). The dependence of sedimentation coefficients of oligonucleosomes on the number of nucleosomes in the chain have been studied in the range of ionic strength from 0.005 to 0.085. Analysis of these data indicates that such structural parameters of sea urchin sperm chromatin fibre as the diameter of the chain and the length of the chain per nucleosome are quite similar to those of chromatin with shorter linker DNA, but the DNA packing ratio is higher. The structure of sea urchin sperm oligonucleosomes agrees well with the model of three-dimensional zig-zag-shaped chain with linker DNA forming a loop. The possible role of alpha-helical regions of the C-terminal domain of sea urchin sperm histone H1 in the long linker DNA folding is discussed.

Outer-arm dynein from trout spermatozoa: substructural organization

Outer-arm dynein purified from trout spermatozoa was disrupted by low-ionic-strength dialysis, and the resulting subunits were separated by sucrose density-gradient centrifugation. The intact 19 S dynein, containing the alpha- an beta-heavy chains, intermediate chains (ICs) 1-5 and light chains (LCs) 1-6, yielded several discrete particles: a 17.5 S adenosine triphosphatase (ATPase) composed of the alpha- and beta-chains ICs 3-5 and LC 1; a 9.5 S complex containing ICs 1 and 2 together with LCs 2, 3, 4, and 6; and a single light chain (LC 5), which sedimented at approximately 4 S. In some experiments, ICs 3-5 also separated from the heavy chain complex and were obtained as a distinct subunit. Further dissociation of the 17.5 S particle yielded a 13.1 S ATPase that contained the beta-heavy chain and ICs 3-5. The polypeptide compositions of the complexes provide new information on the intermolecular associations that occur within dynein. Substructural features of the trout dynein polypeptides also were examined. The heavy chains were subjected to vanadate-mediated photolysis at the V1 sites by irradiation at 365 nm in the presence of Mg2+, ATP, and vanadate. Fragment pairs of relative molecular mass (Mr) 245,000/185,000 and 245,000/170,000 were obtained from the alpha- and beta-heavy chains, respectively. Photolysis of these molecules at their V2 sites, by irradiation in the presence of vanadate and Mn2+, yielded fragments of Mr 160,000/270,000 and 165,000/250,000, respectively. These values confirm that the alpha- and beta-heavy chains have masses of 430,000 and 415,000 daltons, respectively. Immunological analysis using monoclonal antibodies revealed that one intermediate chain from trout dynein (IC 2) contains epitopes present in two different intermediate chains from Chlamydomonas dynein. This indicates that specific sequences within the dynein intermediate chains have been highly conserved throughout evolution.

Effects of freezing-thawing on the spermatozoon nucleus: a comparative chromatin cytophotometric study in the porcine and human species

Freezing-thawing effects on the nuclei of porcine and human spermatozoa were studied by determining native DNA percentage from fluorescence after acridine orange (AO) staining and by analyzing chromatin structure by a quantitative microspectrophotometric study of Feulgen-DNA complexes before and after freezing. The study of boar spermatozoa revealed no alteration in native DNA percentage after freezing. However, native DNA percentage decreased significantly in human spermatozoa. Feulgen-DNA content and sperm nuclear surface area decreased in both species after freezing. These results prompted us to hypothesize an overcondensation of sperm chromatin after freezing-thawing. This overcondensation may be related to the lower conception rates obtained with human and porcine semen after cryostorage via defective decondensation.

Immunomagnetic method to select human sperm without sperm surface-bound autoantibodies in male autoimmune infertility

Using supermagnetic polymer microspheres coated with anti-immunoglobulins, spermatozoa without autoantibodies bound on their surface can be isolated from a sperm population showing a variable percentage of cells with autoantibodies bound on their surface. This simple technique seems to induce no modification of semen qualities; therefore, the concentration of sperm after immunomagnetic separation might be useful for in vivo or in vitro insemination in infertile couples with autoimmune male infertility.

Evaluation of the semi-automated Autosperm semen analysis system. II. Comparison with conventional method, time-exposure photomicrography, and automated CellSoft system

Semen analysis results obtained by a recently developed semi-automated Autosperm system (Amsaten N.V.S.A. Corp., De Pinte, Belgium) were compared with those obtained by the conventional, time-exposure photomicrographic, and automated CellSoft system (Cryo Resources Inc., New York, NY) analyses. The Autosperm system either over- or underestimated the sperm concentration in comparison with the conventional analysis and more often underestimated the sperm concentration in comparison with the automated CellSoft system analysis. Comparison of the results for percent sperm motility by the conventional and Autosperm analyses showed that the latter tended to underestimate the percentage of fast-swimming spermatozoa and overestimate the percentage of slow-swimming spermatozoa. There were considerable variations in the measurement of sperm movement characteristics between the Autosperm and time-exposure photomicrographic and automated CellSoft system analyses, respectively. These findings demonstrate that the performance of the Autosperm system does not agree well with those of the currently available methods employed in the present study. Part of the disagreement in measurements of sperm parameters could be because of the subjective elements inherent in the semi-automated Autosperm analysis.

Evaluation of the semi-automated Autosperm semen analysis system. I. Accuracy and comparison with the conventional method and the automated Hamilton-Thorn system

The accuracy of measurements by the semi-automated Autosperm (Amsaten N.V.S.A. Corp., DePinte, Belgium) semen analysis system was assessed by recounting and manually tracking sperm recorded on videotape during analysis of 51 ejaculates. Mean inaccuracies in the analysis of sperm concentration and percentage motility were 15% and 22%, respectively. Measurements of sperm movement characteristics relied on the skill of the operator and discrepancies (means around 10%, maximum 57% to 184%) depended on the straightness of sperm paths. Although less expensive than the fully automated system, semen analysis by Autosperm is a subjective and labor-intensive method. Furthermore in comparison, data obtained using Autosperm also provide less information, and agreements of matched data with those obtained by the conventional methods were not significantly better.

Differences in lipoprotein composition between heads and tails of human sperm: an infrared spectroscopy study

Human spermatozoa and their fractions (heads and tails) have been studied by infrared spectroscopy. Protein conformation in isolated human spermatozoa heads, although predominantly of the alpha helix or random coil type, has a significant proportion of antiparallel B structure. Spectra of isolated spermatozoa tails show that proteins exist in this fraction preponderantly in pleated-sheet conformation (parallel and antiparallel). The quantity and type of lipids seem to be drastically different between heads and tails of spermatozoa. Head lipids are scarce and difficult to extract, and they are apparently tightly bound to proteins, highly unsaturated, and rich in free hydroxyl and carboxyl groups. Tail lipids are more abundant and more easily extractable. Head phospholipids are probably phosphatidylcholine, cephalins, and inositols, and tail phospholipids are preponderantly plasmalogen-type lecithins and sphingomyelins. The presence of specific infrared bands points to the existence in tails of important amounts of sulfur compounds, probably sulfolipids or sulfoglycolipids.

Genomic distribution of copia-like transposable elements in somatic tissues and during development of Drosophila melanogaster

The genomic distribution of elements of the copia, 412, B 104, mdg 1, mdg 4 and 1731 transposon families was compared by the Southern technique in DNA preparations extracted from brains, salivary glands and adult flies of two related Drosophila lines. The copia, 412 and mdg 1 sequences were also probed in DNA from sperm, embryos, and 1st and 2nd instar larvae. The homogeneity of the patterns observed shows that somatic transposition is unlikely to occur frequently. A correlation between mobility and the euchromatic or heterochromatic location of transposable elements is discussed. In addition, an explanation of the variable band intensities of transposable elements in Southern autoradiographs is proposed.

Identification of peanut agglutinin receptors on mouse testicular germ cells

Peanut agglutinin receptors expressed specifically in mouse testicular germ cells have been identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and lectin blotting techniques. Two major components were estimated to have molecular weights of 86,000 and isoelectric points of 6.1 +/- 0.3 and 6.2 +/- 0.3. Minor components with molecular weights of 71,000-74,000 and isoelectric points of 6.1 +/- 0.3 were also detected. Specific expression of these receptors on testicular germ cells was confirmed using the testes of mutant mice, Sld/Sld, devoid of germ cells.

Detection of sperm-bound antibodies in the male partners of infertile couples using the immunobead test

The aim of this investigation was to determine the incidence of sperm-bound antibodies in the male partners of an unselected infertile population using an immunologically specific test (IBT). With this method 34 out of 450 infertile men (7.55%) were positive for one or more of the immunoglobulins IgA, IgG and IgM. For IgG and IgA, the majority of antibody binding was located on the entire sperm with a minor amount bound to the head or tail. For the IgM, the majority of the binding was detected to the tail tip, and tail binding was observed only in a minority of cases.

Analysis of the membrane-interacting domain of the sea urchin sperm adhesive protein bindin

We have investigated the domain of the bindin polypeptide that selectively associates with gel-phase phospholipid vesicles. We found that small trypsin fragments of bindin retain the ability to selectively associate with gel-phase vesicles. The primary amino acid sequence of bindin suggests that these peptides are derived from the central portion of the polypeptide between residues 77 and 126, which is the most hydrophobic region of bindin. We have also employed 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine (TID) and novel, radioiodinated, photoactivatable derivatives of the polar head group of phosphatidylethanolamine (ASD-PE and ASA-PE) to identify membrane-associated polypeptide segments after the transfer of radiolabel from the probe to the bindin polypeptide. After photolysis, bindin was selectively labeled only from probes incorporated in gel-phase vesicles. The labeling of bindin was much more efficient from the head group probes ASA-PE and ASD-PE (8 and 2% of the total label, respectively) in comparison to the hydrophobic probe TID (less than 0.02% of the total label), suggesting that bindin is localized within the polar part of the bilayer. Protease mapping experiments with V8 protease, trypsin, and endoprotease Lys-C suggest that some of the probe label is distributed along the amino-terminal portion of bindin between residues 1 and 76 and the rest of the label is restricted to the segments between residues 77 and 126 which also selectively bind to gel-phase vesicles. The carboxyl-terminal portion of bindin between residues 127 and 236 is not labeled.

Intracellular pH regulates bovine sperm motility and protein phosphorylation

Bovine sperm in neat caudal epididymal fluid become motile in response to either pH elevation or dilution of the fluid. Buffers containing permeant weak acids at physiologic concentrations are able to mimic these effects of caudal fluid. These observations lead to the hypothesis that a pH-dependent epididymal fluid quiescence factor regulates bovine sperm motility by modulating sperm intracellular pH (pHi). Here we report that sperm pHi, measured with the fluorescent pH probe carboxyfluorescein, increases by approximately 0.4 units in response to either of these motility-initiating manipulations. At least 26 discrete phosphoprotein bands are distinguishable by sodium dodecylsulfate-polyacrylamide gel electrophoresis after incubation of intact caudal sperm with 32PO4. A prominent phosphoprotein, with Mr approximately 255,000 (pp255) and a relatively high specific radioactivity, is reversibly dephosphorylated in response to elevations in pHi that initiate sperm motility. Unlike most of the sperm phosphoproteins, the extraction of pp255 requires reducing agents. This phosphoprotein cosediments with the sperm heads but not the tail, midpiece, soluble, or plasma membrane fractions. No other pHi-dependent phosphorylation changes are apparent in gels of whole sperm extracts. However, subcellular fractionation allows the detection of increased phosphorylation of two plasma membrane phosphoproteins (Mr approximately 105,000 and 97,000) and decreased phosphorylation of another plasma membrane phosphoprotein (Mr approximately 120,000) in response to increasing pHi. This is the first report describing changes in endogenous phosphoproteins from intact motile and nonmotile bovine sperm that are regulated by pHi.

[Diagnostic in-vitro fertilization]

Unexplained sterility is one of the major problems in the treatment of childless couples. The reason for sterility can be the result of different factors such as andrological or anatomic-physiological dysfunctions. The therapeutic approach to treat patients with unexplained sterility at the Department of Obstetrics and Gynecology, University of Goettingen, is, to exclude those patients from further therapies who obviously have no chance to become pregnant by any technique of reproductive medicine. A so called "diagnostical IVF" gives information about the fertilization capacity of male and female gametes in vitro. The results of a one year study with 85 couples (tubal sterility = 57; idiopathic sterility = 28) indicated, that even with no differences in the number of oocytes retrieved, the fertilization and cleavage rates were significantly higher in the group of patients with tubal sterility (fertilization rate: 63.1% vs 46.1%; cleavage rate: 57.5% vs 40.6%). Thus the transfer rate in patients with unexplained sterility was about 15% lower (68.9%) than in patients with tubal sterility (85.6%). On the other hand, after embryo transfer the pregnancy rate was double in those patients with unexplained sterility (38.7 vs 15.7%). If there is no fertilization of the oocytes in at least two IVF cycles all attempts to fulfill the patients desire for a child seem useless. In contrast successful in vitro fertilization provide the bases for further intrauterine insemination cycles which can be assisted by psychotherapy. This regimen seems helpful to classify patients with unexplained sterility and avoids long lasting frustrating therapies.

[The adenosine phosphate content in human sperm and their motility]

Adenosine phosphoric acids (ATP, ADP, AMP) are of significance for the metabolic processes in living beings, including spermatozoa, as they are the principal donors of energy in all the reactions of biosynthesis. Besides, spermatozoa need the energy to perform a particular function-to move in the female genital tract to the ovum. It was stated that a decrease in the ATP levels reduced or ceased the translational motion of spermatozoa, therefore the investigations of adenosine phosphates in the spermatozoa were found to be mandatory. The authors studied the levels of ATP, ADP and AMP and the energy charge in the native human spermatozoa in the patients with oligo- and asthenospermia. Spermatozoa with morphologically and physiologically normal fertility were used as controls. The results obtained demonstrated that in oligospermic males the levels of ATP were slightly decreased whereas the levels of AMP significantly increased from 31.6 to 38 per cent. As a result there was a significant decrease in the ATP/ADP ratio. A more pronounced decrease in the ATP levels and an increase in the AMP levels were revealed in asthenospermic patients (12.6 and 40.5 per cent respectively. In the latter patients the ADP fraction decreased to 42.4 per cent versus 51.4 per cent in health and the energy charge underwent a more significant decrease: from 0.37 (normal) to 0.3. The results obtained are indicative of the possibility of using the aforementioned method for a comprehensive evaluation of the spermatozoan functional activity and the detection of asthenospermia-inducing mechanisms.

Immunogold distribution of actin during spermiogenesis in the normal rabbit and after experimental cryptorchidism

Immunogold procedures for actin detection were used in combination with experimental cryptorchidism in the rabbit as a model to shed more light on the function of subacrosomal actin during spermiogenesis. In the normal testis, actin was localized in the perinuclear substance (PNS) from round spermatid onward but it was not detected in late spermatids. Actin labeling in each type of spermatid was essentially unmodified after 24 hr of cryptorchidism. However, among relevant immediate and delayed effects, discontinuous acrosomes overlying a continuous PNS with normal actin labeling were noted. Nuclear invaginations were seen in combination with subacrosomal dilatations; at this site actin labeling was found only in the PNS closely apposed to the nuclear envelope. In subacrosomal areas lacking PNS, actin labeling also was lacking. These results suggest that the subacrosomal actin (F-actin) is a component of the PNS that is tightly bound to the nuclear envelope rather than the overlying inner acrosomal membrane. Therefore, a function for the subacrosomal actin either in anchoring the acrosome to the nucleus or in capping the inner acrosomal membrane appears unlikely. The data rather suggest a capping function for the nuclear membrane during spermiogenesis.