A. G. Burrini

The accessory fibers of the sperm tail: III. High-sulfur and low-sulfur components in mammals and cephalopods1

Purified mammalian accessory fibers consist of two groups of disulfide-cross-linked polypeptide chains: The high molecular weight chains (42 000–72 000 daltons) are rich in aspartic acid, glutamic acid, and leucine; the low molecular weight chains (28 000–31 000 daltons) are rich in cysteine and proline. The infrared spectrum of whole fibers is similar to that of keratin. Protofibril-like structures, 2 nm thick, are detected in native fibers and become more evident after proteolysis or “renaturation” from guanidine-HC1 solutions. The cross-striation of accessory fibers originates from the lateral packing of protofibril-like units. Cephalopod accessory fibers are also resolved into two groups of disulfide-cross-linked chains: as in mammalian fibers, the high molecular weight chains (about 90 000 daltons in both Eledone moschata and E. cirrhosa) contain large amounts of aspartic acid, glutamic acid, and leucine; the low molecular weight group (about 50 000 and 30 000 daltons in E. moschata, 36 000 daltons in E. cirrhosa) contains large amounts of cysteine, proline, and histidine. The occurrence of low-sulfur and high-sulfur polypeptides, the zinc-binding properties (6), and the analogous localization in wave-generating flagella prompt the authors to distinguish the keratin-like proteins of sperm accessory fibers of mammals and cephalopods with the new name of parergins.

The accessory fibers of the sperm tail. II. Their role in binding zinc in mammals and cephalopods.

In mammals (bull, rat, man) and cephalopods ( Eledone moschata, E. cirrhosa, Octopus vulgaris ) most of the sperm zinc is concentrated in the flagellar accessory fibers (outer dense fibers). Calcium, magnesium, and copper show a more diffuse subcellular localization. This statement is based on electron probe microanalysis and on biochemical studies on fibers purified by density step centrifugation. The accessory fibers also account for the highest percentage of sulfhydryl groups in both mammalian and cephalopod sperm. Compared to other sperm structures, there is a low degree of protein cross-linking through -S-S- groups. Evidently the sulfhydryl groups are involved in the binding of zinc. Zinc binding groups other than -SH groups are also present, particularly in cephalopod fibers where high amounts of histidine are detected. The results may be related to the mechanical properties of the accessory fibers and to the action exerted by zinc on sperm motility.

9 + 0 immotile spermatozoa in an infertile man.

“9 + 0”‐unbewegliche Spermatozoen bei einem unfruchtbaren Mann

Notulae seminologicae. 2. The "short tail" and "stump" defect in human spermatozoa.

Summary. In this note several cases of stunted tails involving the total sperm population in sterile humans are described. Half of the cases are classified as ‘short tailed’ spermatozoa, the other half as ‘stump defect’ previously described in bulls. Both defects are referred in details at electron microscopical level.

Spermatozoa and cilia lacking axoneme in an infertile man.

Fehlen des Axonema bei Spermatozoen und Cilien eines unfruchtbaren Mannes

Localisation of two classes of acetylcholine receptor-like molecules in sperms of different animal species

The distribution of different classes of acetylcholine (ACh) receptor-like molecules in sperms of different invertebrate and vertebrate species is described. ACh receptor molecules belong to one of two classes: muscarinic receptors (mAChRs), associated with signal transduction mechanisms in the inner domain of the cell, and nicotinic receptors (nAChRs), capable of opening Na+ channels when activated by the ligand. Molecules immunologically related to mAChRs and to ACh can be identified by specific antibodies, and revealed by immunofluorescent or immunogold staining; the nicotinic receptor-like molecules are localised as curare-sensitive affinity sites for alpha-bungarotoxin. In all species studied, both classes of receptors were found, with a similar distribution. Muscarinic-like molecules were found mainly in the sperm head regions of most species; such a localisation may be correlated to a function in sperm-egg interaction, for instance in the regulation of the block to polyspermy. Nicotinic-like molecules are present mainly in the tail and in the post-acrosomal region of most animals, thus confirming their function in the regulation of sperm propulsion, but are also present at the acrosomal region of most species. The distribution patterns of the different classes of molecules indicate that both may be involved in sperm-egg interactions, in addition to their known function in the regulation of sperm propulsion.

The morphogenesis of vertebrate perforatorium.

The perforatorium morphogenesis in birds and mammals spermatid evolution is described. In all cases studied by us, the perforatorium morphogenesis begins with an assembly of actin, demonstrated by HMM decoration and immunostaining with AA antibodies, which initiates with the classical nucleation granule of invertebrates, the actomere, in birds, or in an ample perinuclear area in mammals. The role played by the subacrosomal actin during spermiogenesis is discussed.

Localization and catalytic properties of lactate dehydrogenase in different sperm models

Abstract A study of the intracellular localization and catalytic properties (effects of substrates and products) on lactate dehydrogenase has been carried out on a series of spermatozoa endowed with mitochondria and characterized by aerobic metabolism of fatty acids (sea urchin); aerobic metabolism of fatty acids and exogenous carbohydrates and lactic acid (bull); metabolism of glycogen connected with mitochondria ( Lebistes ); metabolism of periaxonemal glycogen ( Octopus ). The data obtained indicate that LDH is present only when carbohydrates are metabolized; its localization follows the glycogen stores; in the Octopus sperm where mitochondria are poorly developed relative to the flagellar length, and exogenous lactate is not available, LDH catalyses predominantly the reduction of pyruvate; in Lebistes and trout sperms, where mitochondria are better developed, LDH is more similar to the mammalian heart and sperm isozymes.

Notulae seminologicae. 1. New combinations of Kartagener's syndrome

Summary. In this note new consequences of the Kartageners syndrome are described. In males the syndrome involved a diffused sperm immaturity; in one female severe skeletal defects were present probably resulting from bad organization of the renal apparatus.

The cell surface during mammalian spermiogenesis

Abstract In this paper the origin of the membrane investing the newly formed elongating organelles during mammalian spermiogenesis is studied. According to previous authors, the beginning axoneme is hollowed in a deep membrane invagination. We demonstrate that in man, rat, and bull this new surface is formed by several clusters of Golgi-originated vesicles which form a periaxonemal double cylinder which finally fuses at its end with the old plasma membrane. So the new periaxonemal plasma membrane is preformed in the spermatid body. The membrane surrounding the elongating head is, on the contrary, simply an extension of the old one, because migration of Golgi vesicles and preformed new membranes have not been observed in this region. Con A properties of new and old membranes are the same and will change only after the transit through the epididymis.