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Motile rabbit sperm tails that lack heads are immobilized by antibody plus complement. Accordingly, immunological immobilization may not necessarily require the extensive sperm acrosomal damage previously reported in immobilized normal sperm.
Sperm tails and bronchial cilia from Polynesians with bronchiectasis were examined in the electron microscope. The outer doublet tubules of the axonemal skeleton in these organelles either lacked dynein arms or had only partial arms. Various other cilial abnormalities were common. The sperm were immotile and pulmonary mucociliary clearance was reduced or absent.
Selenium is necessary for normal sperm tail development in the rat. The biochemical locus of this requirement was investigated by intratesticular administration of (75Se)SeO3-2. Sperm were labeled primarily in tail keratin, a disulfide-stabilized fraction obtained by extracting isolated tails with sodium dodecyl sulfate (SDS). By incubation in 1% SDS-0.2 mM dithiothreitol, followed by sonication and centrifugation, the 75Se was separated from a residue rich in S and Zn, composed of dense fibers and connecting pieces. The extracted 75Se-labeled material was non-dialyzable, sensitive to pronase, retained most of its bound isotope following carboxymethylation, and displayed only one radioactive component, of 17,000 daltons, during SDS-polyacrylamide gel electrophoresis. It is suggested that the labeled moiety is a selenopolypeptide whose function is critical for normal assembly of the sperm tail.
Several integrins recognize as ligands proteins containing the Arg-Gly-Asp (RGD) sequence, such as fibronectin, vitronectin, and laminin. It has been previously demonstrated that oligopeptides containing the RGD sequence competitively inhibit both the adhesion of hamster and human sperm to zona-free hamster eggs and their subsequent penetration. In addition, the appearance of fibronectin on the surface of living human spermatozoa after capacitation has been demonstrated. In this work, it is shown that spermatozoa incubated overnight under capacitating conditions, but not fresh spermatozoa, also display the RGD-containing proteins vitronectin and laminin. Whereas the expression of fibronectin does not appear to be localized to any specific region of the sperm surface, laminin is present solely on the sperm tail, and vitronectin was detected mostly as an equatorial band on the sperm head. The percent of capacitated spermatozoa within each ejaculate reacting with antivitronectin antibodies (51% to 94%) was similar to that observed with antifibronectin antibodies (72% to 100%) in a series of fertile donors, and in a series of infertile men (7% to 98% for vitronectin versus 5% to 100% for fibronectin). In contrast, the percent of spermatozoa displaying laminin was lower, ranging from 2% to 42% for fertile donors and from 5% to 34% for infertile donors, and was unrelated to the expression of fibronectin or vitronectin. The time of appearance of both fibronectin and vitronectin when spermatozoa were incubated under capacitating conditions varied for different sperm donors, suggesting a difference in the process of their expression between different men. The specificity of antivitronectin antibody binding to human spermatozoa was demonstrated by competitive inhibition with purified human vitronectin. That there was no immunologic reaction between the antivitronectin antibodies used and fibronectin was demonstrated both by the failure of free fibronectin to inhibit antivitronectin antibody binding to spermatozoa, and by Dot blot analysis. A partial cross-reaction of the polyclonal antivitronectin antibody with fibronectin was shown by Western blot analysis, but this phenomenon was not present when the monoclonal antivitronectin antibody was used. In addition, both fibronectin and vitronectin could be extracted from capacitated spermatozoa solubilized in Chaps buffer, as shown by Dot blot and Western blot analysis. These observations suggest that vitronectin and fibronectin expressed on the surface of capacitated human spermatozoa could act as a ligand for specific receptors on the egg, and play a role in sperm-oolemmal adhesion.
The zinc content was determined in semen samples from four young Danish Jersey bulls showing the typical 'Dag defect' (greater than 50% strongly coiled or bent sperm tails). Two of the bulls were half brothers. Semen samples from 14 normal fertile Jersey bulls served as controls. The normal material showed a zinc content in the centrifuged sperm of 190 +/- 15.8 mug/g d.w. and in the seminal plasma 81 +/- 31.2 mug/g d.w. In the four abnormal bulls the following elevated values were found: in the centrifuged sperm 310 +/- 109.5 mug/g d.w. and in the seminal plasma 137 +/- 75.2 mug/g d.w. (see figs. 1 and 2). One of the Dag defect's main localizations, the outer dense tail fibers, has a very high zinc content and this fact together with the heredity of the defect make further studies most promising.
Tritium-labeled viblastine, specific activity 107 Ci/mol, was prepared by acetylation of desacetylvinblastine with [3H]acetic anhydride, and has been employed in a study of vinblastine binding to tubulin. There are two high affinity vinblastine-binding sites per mole of embryonic chick brain tubulin (KA = 3-5 X 10(5) l./mol). Binding to these sites was rapid, and relatively independent of temperature between 37 and 0degreeC. Vincristin sulfate and desacetylvinblastine sulfate, two other active vinca alkaloid derivatives, competitively inhibited the binding of vinblastine. The inhibition constant for vincristine was 1.7 X 10(-5) M; and for desacetylvinblastine, 2 X 10(-5) M. The vinblastine binding activity of tubulin decayed upon aging, but this property was not studied in detail. Vinblastine did not depolymerize stable sea urchin sperm tail outer doublet microtubules, nor did it bind to these microtubules. However, tubulin solubilized from the B subfiber of the outer doublet microtubules possessed the two high affinity binding sites (KA = 1-3 X 105 l./mol). These data suggest that vinblastine destroys microtubules in cells primarily by inhibition of microtubule polymerization, and does not directly destroy preformed microtubules.
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Motile spermatozoa from the golden hamster have been arrested by rapid freezing and then fixed with glutaraldehyde at low temperature after substitution with ethylene glycol. As far as can be judged, the flagellar waveforms thus stabilized are similar to those seen in living sperm; in contrast, fixation in glutaraldehyde, without prior freezing, induces agonal changes in flagellar conformation. The characteristics waveform after freeze substitution contains three bends. Approx. half of these flagella are entirely planar. The rest are three dimensional, with the third bend displaced in a regular way from the plane containing the proximal two bends. From the geometry of these flagella, it is concluded that the plane of action of a given bending cycle undergoes a clockwise twist (from a forward viewpoint) as the cycle is succeeded by new bending cycles. This "twisted plane" undulation is quite different from helical movement. The twisting seems to occur abruptly, between cycles, as if each bending cycle has a preferred plane of action. The mechanism underlying the twisting is uncertain. However, on the basis of the angular displacements between the preferred planes, and the findings from electron microscopy, the following idea is presented as a working hypothesis: that, if the most proximal plane of bending is topographically determined by peripheral doublet 1, then successive distal planes of action are influenced predominantly by doublets 2, 3, etc., in clockwise sequence. The merits and weaknesses of this hypothesis are discussed.
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Large numbers of spermatozoa with bent or coiled tails were found in the ejaculates of rhesus monkeys treated with 1-(2,4-dichlorobenzyl-indazole-3-carboxylic acid (DICA) (50 or 500 mg/kg for various periods). The defect appeared only in spermatozoa in the cauda epididymidis and consisted of axoneme disarrangement and loss of the fibre doublets. The coil was completely enclosed in a membrane.
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A case of sterility in an 18-month-old bull of the Holstein-Friesian breed was investigated. A semen sample sent to the laboratory showed a very low sperm concentration and abnormal sperm morphology. On the preliminary examination, the major sperm defect (60-70%) seemed to be tailless heads. When higher manification was used it was found that most of the defective heads had a short tail rudiment, a tail stump 2-3 mu long. Loose sperm tails were seldom seen in the smears. The defect has been described previously from Canada where it has occurred in different breeds, including Holstein-Friesians. The dam of the Danish bull in question was inseminated with imported American semen, and the sire is one of the most demanded Holstein-Friesian bulls at present. The possible heredity of the defect is discussed.
We investigated six men and a woman suspected of suffering from congenital immotility of cilia. All had chronic airway infections, and the men had immotile spermatozoa. The woman and three men had Kartagener's syndrome. The investigations included measurements of the mucociliary transport in the lower airways and ultrastructural studies of the sperm tails or respiratory cilia (or both). Mucociliary transport was significantly delayed. Sperm tails lacked dynein arms in five patients. Respiratory cilia from the women and two men lacked dynein arms and were irregularly oriented. The results support the hypothesis that a congenital defect in the cilia and sperm tails will cause chronic respiratory-tract infections and male sterility--the immotile-cilia syndrome. In about half these patients there will also be a situs inversus--i.e., Kartagener's syndrome.