Showing papers on "Sperm published in 1980"

Laboratory manual for the examination of human semen and semen-cervical mucus interaction.

Abstract: This laboratory manual consists of 2 sections which describe methods of examination of human semen and semen-cervical mucus interaction in order to standardize procedures and facilitate evaluation and comparison of research reports The section on semen collection and examination discusses and makes recommendations for sample collection and delivery; initial examination; motility assessment estimation of sperm density; examination of particulate debris; agglutination; sperm viability; counting the spermatozoa; and analysis of morphological characteristics of germinal cells including preparation of seminal fluid smears staining method and classification and quantification of germinal cells and leucocytes Photomicrographs are provided to demonstrate morphological characteristics of normal and abnormal mature sperm immature germinal cells and leucocytes and epithelial cells Appendices provide information on frequency of various sperm forms in a normal ejaculate Papanicolaou staining procedure for sperm and the Bryan/Leishman stain for seminal fluid morphology smears A sample record for sperm analysis is also included The section on sperm-cervical mucus interaction describes the composition and characteristics of the mucus the collection procedure storage and preservation and evaluation including pH Methods of evaluating sperm-cervical mucus interaction are then described The timing and techniques of the post-coital test vaginal pool sample exocervical and low cervical samples and endocervical samples and their interpretation are discussed Instructions are provided for in vitro studies including the capillary tube test and the slide technique

Relation of mammalian sperm chromatin heterogeneity to fertility.

Abstract: Flow cytometry of heated sperm nuclei revealed a significant decrease in resistance to in situ denaturation of spermatozoal DNA in samples from bulls, mice, and humans of low or questionable fertility when compared with others of high fertility. Since thermal denaturation of DNA in situ depends on chromatin structure, it is assumed that changes in sperm chromatin conformation may be related to the diminished fertility. Flow cytometry of heated sperm nuclei may provide a new and independent determinant of male fertility.

Sperm Utilization Strategies in Nonsocial Insects

Abstract: It is postulated that the sperm precedence characteristics of most insect populations have resulted primarily from selection on females (1) to optimize the genetic composition of their progeny; (2) to discourage or encourage multiple matings for reasons other than genetic considerations; (3) to optimize their sperm storage capacity and utilization. In addition, selection on males to maximize egg fertilization by reduced displacement of their sperm and increased displacement of other sperm to the extent that these can be achieved without sacrificing the optimal mating strategy (Parker 1970a) probably has been important in some species. Parker's (1970a) hypothesis that the amount of sperm displacement in a population should stabilize at the value which yields the optimal overall male fertilization rate is accepted as the optimal male strategy; however, it is suggested that females often largely determine, by their behavior and by the structure and functioning of their reproductive tract, the optimal male st...

Calcium-induced quiescence in reactivated sea urchin sperm.

Abstract: Sperm flagella of the sea urchin Tripneustes gratilla beat with asymmetrical bending waves after demembranation with Triton X-100 in the presence of EGTA and reactivation at pH 81 with 1 mM ATP in the presence of 2 mM MgSO4 Addition of 01--02 mM free Ca2+ to these reactivated sperm induces 70--95% of them to become quiescent This quiescence can be reversed by reduction of the free Ca2% concentration with EGTA, or by dilution to reduce the MgATP2- concentration below 03 mM The quiescent waveform is characterized by a sharp principal bend of approximately 56 rad in the proximal region of the flagellum, a slight reverse bend in the midregion that averages approximately 03 rad, and a principal bend of approximately 11 rad in the tip The quiescent sperm are highly fragile mechanically, and disruption, including microtubule sliding, occurs spontaneously at a slow rate upon standing or immediately upon gentle agitation Mild digestion by trypsin causes a gradual appearance of normal, symmetrical flagellar beating Addition of increasing concentrations of vanadate to quiescent sperm causes a graded decrease in the proximal bend angle, with 50 micrometers vanadate reducing it to approximately 26 rad In the presence of 01 mM free Ca2% and 10 micrometers vanadate, a characteristic, crescented stationary bend is induced in the demembranated sperm, without intermediate oscillatory beating, by the addition of either 01 or 1 mM ATP In the absence of vanadate, these two concentrations of ATP produce asymmetric beating and quiescence, respectively The results support the hypothesis that quiescence in live sperm is induced by an elevated concentration of intracellular Ca2% In addition, they demonstrate that bending can occur in flagella in which oscillatory beating is inhibited and emphasize the close relationship between asymmetric beating and quiescence

Studies on the mechanism of capacitation: albumin-mediated changes in plasma membrane lipids during in vitro incubation of rat sperm cells.

Abstract: Plasma membrane isolated from rat sperm cells after incubation in vitro had a significantly lower cholesterol/phospholipid mole ratio when the medium contained serum albumin. Transfer of albumin-bound phospholipids to the membrane can largely account for this effect. The result is broadly consistent with a previously proposed model for albumin-induced destabilization of sperm membrane (capacitation) and its reversal by seminal plasma membrane vesicles. Albumin also decreased sialic acid and, more specifically, ganglioside levels, presumably by promoting release of sperm neuraminidase. Cholesteryl ester comprised up to 0.5 mol/mol of cholesterol in these plasma membrane preparations.

Thermal induction of diploid gynogenesis and triploidy in the eggs of the rainbow trout (Salmo gairdneri Richardson).

Abstract: Sporadic diploid gynogenetic fry resulted from fertilization with gamma-irradiated sperm. Their frequency increased appreciably when thermal shock treatments, beginning during the first hour of development (--0.4 degrees C lasting 6 hrs 45 min; 26-30 degrees C lasting 10 min), were used. When the eggs were fertilized with normal sperm, a good triploidization rate was induced by means of heat shocks (27-30 degrees C lasting 10 min). It is supposed that the retention of the second polar body caused the gynogenetic diploidy observed.

Taurine and hypotaurine: their effects on motility, capacitation and the acrosome reaction of hamster sperm in vitro and their presence in sperm and reproductive tract fluids of several mammals*

Abstract: Previous work from this laboratory has shown that the β-amino acid taurine can support and stimulate hamster sperm motility during in vitro capacitation in the presence or absence of epinephrine The present report describes in vitro results which demonstrate that hypotaurine, a precursor of taurine, can also support and stimulate motility under these conditions and that a higher number of acrosome reactions occur in the presence of taurine as compared to hypotaurine (both in the presence and absence of epinephrine) In all cases, the greates percentage of acrosome reactions occurs in the presence of epinephrine Whether these β-amino acids act independently of epinephrine of in a synergistic manner with it remains to be determined In addition to these in vitro studies, we report that hypotaurine and taurine are present at high levels in bovine follicular fluid, rabbit uterine and ampullar oviductal fluid (11 hr after mating, ie, 1 hr after ovulation), monkey oviductal fluid, bovine adrenal cortex “motility factor” preparation and human, guinea pig and hamster sperm preparations Based on these results, we suggest the possibility that taurine and hypotaurine may have roles in vivo in the maintenance and stimulation of sperm motility and stimulation of capacitation and/or acrosome reactions

Gametogenesis and early development of the temperate coral astrangia danae (anthozoa : scleractinia)

Abstract: 1. The coral Astrangia danae is dioecious, with an early age of first reproduction.2. In Narragansett Bay, this species exhibits an annual reproductive cycle with gametogenesis starting in March-April. Spawning occurs during August, and vestigial gametes are absorbed during the winter months.3. Gametes originate from interstitial cells which differentiate in the mesenterial mesoglea.4. Ova are 100-130-µm in diameter and sperm are 2-3-µm in length, excluding the tails. Egg production was estimated at up to 6000 eggs per polyp.5. Fertilization and development are external; no fertilization membrane was seen even though a layer of cortical vesicles was present before fertilization.6. Embryonic cell divisions are around 30 min apart and the larval planual stage is reached within 12-15 hr after fertilization. Larval settlement was not observed.7. Ova from colonies containing zooxanthellae did not contain zooxanthellae when spawned.

Evidence supporting the existence of sperm maturation in the human epididymis

Abstract: Zona-free hamster oocytes were used to evaluate the penetrating capacity of spermatozoa recovered from the caput, corpus and cauda segments of 5 human epididymides. The ability of spermatozoa to bind tightly to oocytes increased in spermatozoa from successive segments. However, only spermatozoa recovered from the cauda epididymidis were able to penetrate the oocytes (26%). These results suggest that, in man, a gradual process of sperm maturation occurs in the epididymis, as has been observed in numerous other species of mammals.

A study of hetero-specific sperm-egg interactions in the rat, mouse, and deer mouse using in vitro fertilization and sperm injection

Abstract: Hetero-Specific fertilization of zona-free eggs is used in these experiments as a tool to analyze the barriers to hybridization and to gain insight into the mechanisms of normal fertilization. When the zonae of rat eggs, which are a barrier to hetero-specific fertilization, are removed with pronase, the eggs can be fertilized by mouse sperm and the zygotes start to develop normally. A rat egg fertilized with mouse sperm completes meiosis and forms both male and female pronuclei. Chromosomes from both parents are found on the spindle at the metaphase stage of the first cleavage division. Under present culture conditions, embryos develop only to the two-cell stage, but this initial development of the hybrid is apparently normal. The question of whether sperm and egg membrane fusion is requisite for normal development is addressed by injecting sperm directly into the cytoplasm of unfertilized eggs. The injection of mouse sperm into rat eggs frequently leads to activation and formation of male and female pronuclei. The first cleavage division is indistinguishable from that following hetero-specific fetilization. Capacitated and uncapacitated sperm react alike when injected into eggs. Egg activation, however, is necessary for male pronucleus formation. Sperm from the deer mouse Peromyscus maniculatus bairdii, which are incapable of fertilizing even zona-free rat eggs, respond like mouse sperm when injected into rat eggs. These data indicate that sperm interactions with the egg cytoplasm are less species-specific than interactions at the egg surface. Furthermore, the normal surface interactions of sperm and eggs are not essential for the start of development.

Sexual selection and insect sperm.

Abstract: Males produce the smaller gamete. The inconsequence of sperm in comparison to the enormity of eggs has dominated the evolution of male characteristics (Trivers 1972). Females, with their clutches of expensive ova, are limiting resources for which males compete in a variety of ways (Blum and Blum 1979). These different manifestations of masculinity have perhaps, in turn, influenced the radiation of insect sperm morphology and behavior. The following related questions arise from a consideration of sperm both as microorganisms and tools of male reproductive interests: i) Why are there more sperm than eggs? ii) Do sperm behave as individuals? iii) Do competition between ejaculates and conflicts of interest between females and the sperm they contain result in gametic adaptations? Notes on topics indirectly bearing on these problems are placed in an appendix. Why are sperm-to-egg ratios greater than 1? Some mites and insects transfer fewer than 2 sperm per ovum, but these are exceptions to the rule of tens or hundreds of sperm for every egg (Cohen 1971, 1975, 1977). Since only 1 of the multitude can genetically participate in the zygote, why go to the expense of producing such a mass? Males may swamp the female reproductive system with sperm to block the introduction of rival ejaculates (Parker 1970). A contrasting argument holds that gametic exuberance is largely symbolic, a display of a male's ability to obtain resources. Females may make decisions about which male's gametes to use based on the dimensions of their mates' ejaculates (Mary Willson 1979, discussing excess pollen per ovule). These hypotheses have 2 difficulties explaining the full range of insect sperm-to-egg ratios: i) Even in insects whose females mate only once, males transfer excess sperm. In the monogamous mosquito Aedes aegypti, for instance, the male passes 2000 sperm to a female who will lay about 85 eggs (Jones 1968, Christopher 1960). There are, in such cases, no rivals to block or postcopulatory choices between males to be made. ii) Neither specifies an advantage to females who accept excessive numbers of sperm. While the female sometimes expels or digests a portion of the male's ejaculate, the part she stores, and possibly maintains, is often still in excess of the number of ova. Of the 2000 Aedes sperm, about 1000 will make their way to the spermatheca (Jones 1968). Why, then, do males produce more sperm than a female keeps and why does she keep more than she needs? In some cases, males may pass large numbers of sperm as a nuptial gift, a contribution to the good health and fecundity of his offspring's mother (see Thornhill 1976, 1980). It is possible that many are digested in the female genital tract as a source of nourish-

Sperm-egg interaction: evidence for boar sperm plasma membrane receptors for porcine zona pellucida.

Abstract: Freshly ejaculated, noncapacitated boar sperm bind rapidly and in large numbers to pig egg zona pellucida in vitro. In the present study, the number of sperm bound decreased sharply when sperm motility was lowered by energy poisons or by reducing the temperature. Highly motile sperm from humans, guinea pigs, and rats, added at concentrations ten times higher than control sperm, did not bind to the porcine zona. At the same high concentration, a small number of hamster and bull sperm bound to the zona. Binding of boar sperm to the zona pellucida was blocked almost completely by diluted whole antiserum to sperm plasma membranes and by univalent (Fab) antibody to these membranes. When antibody to sperm plasma membrane was first absorbed with plasma membrane vesicles, sperm binding was not inhibited. These results provide direct evidence for the existence of sperm plasma membrane receptors for the zona pellucida of the pig.

The effect of elevated ambient temperature on spermatogenesis in the boar

Abstract: Boars were heated for 6 h/day in a climate chamber (mean maximum temperatures, 33.4±3.1-37.7±2.0°C, and relative humidities 40-80%) for 4, 5 and 7 days respectively (4 boars/group). Significant increases in the proportion of morphologically abnormal spermatozoa were seen in all groups for the end of Week 2 and up to Week 5 after treatment. Boars exposed for 7 days were, in general, more severely affected. Ejaculate volumes, gel volumes, sperm concentration and daily sperm outputs were not affected significantly in any of the groups, although changes were seen in individual animals. In some boars heat stress early in the treatment period produced an acute rise in body temperature which appeared to have a greater effect on semen quality than did the duration of exposure.

Intermittent swimming in live sea urchin sperm.

Abstract: Sperm of the sea urchin Tripneustes gratilla repeatedly start and stop swimming when suspended in seawater and observed by dark-field microscopy. While in the quiescent state, which usually lasts about a second, the sperm assume s shape resembling a cane, with a sharp bend of approximately 3.4 rad in the proximal region of the flagellum and very little curvature in the rest of the flagellum except for a slight curve near the tip. The occurrence of quiescence requires the presence of at least 2 mM Ca2+ in the seawater, and the percentage of sperm quiescent at any one time increases substantially when the sperm are illuminated with blue light. With intense illumination, close to 100% of the sperm become quiescent, and this percentage decreases gradually to approximately 0.3% over a 10(4)-fold decrease in light intensity. An increased concentration of K+ in the seawater also increases the percentage of quiescence, with a majority of the sperm being quiescent in seawater containing 80 mM KCl. The induction of quiescence by light or by increased KCl is completely inhibited by 10 micrometers chlorpromazine, and approximately 90% inhibited by 1 mM procaine or sodium barbital. Sperm treated with the divalent-cation ionophore A23187 swim quite normally, although for a relatively short period, in artificial seawater lacking divalent cations, but are abruptly arrested upon addition of 0.04--0.2 mM free Ca2%. The flagellar waveform of these arrested sperm is almost identical to that of light-induced quiescence in the live sperm. The results support the hypothesis that quiescence is induced by a rise in intracellular Ca2%, perhaps as a consequence of a membrane depolarization, and that it is similar to the arrest response in cilia.

Sperm Autoantigens and Fertilization. I. Eftects of Antisperm Autoantibodies on Rouleaux Formation, Viability, and Acrosome Reaction of Guinea Pig Spermatozoa

Abstract: Fab and IgG were isolated from the sera of 1) guinea pigs immunized with their own epididymal spermatozoa or testis homogenate in complete Freund’s adjuvant, or 2) normal guinea pigs. Their effects on rouleaux formation, the viability, and the acrosomal reaction of guinea pig epididymal spermatozoa were studied in vitro. Monovalent (Fab) antibodies to epididymal spermatozoa and testis homogenate, but not Fab of normal guinea pig serum, rapidly dispersed sperm rouleaux in a dosedependent and time-dependent manner. The effect was reversed by the addition of epididymal spermatozoa and was prevented if the Fab antibody was previously absorbed with guinea pig spermatozoa but not with guinea pig spleen cells or Mycobacterium tuberculosis. Compared with spermatozoa in Fab of normal guinea pig serum, the dispersed spermatozoa were less viable, and the rate of acrosomal reaction was significantly reduced. Contrary to expectation, bivalent (IgG) antibody to epididymal spermatozoa did not agglutinate sperm rouleaux. It prevented head-to-head agglutination of sperm rouleaux and significantly prolonged sperm viability. Most significantly, the acrosome reaction was completely inhibited in the presence of 3.2 X 10’ antibody molecules (to surface antigens of guinea pig spermatozoa) per spermatozoon. The results strongly implicate 1) guinea pig sperm and testicular cell surface autoantigens in the cell adhesion phenomenon leading to rouleaux formation, and 2) guinea pig sperm surface autoantigens in the induction of capacitation and/or acrosome reaction. We further suggest that, in the guinea pig; sperm rouleaux prevent premature acrosome reaction

Comparison of human and mouse sperm chromatin structure by flow cytometry.

Abstract: Human and mouse sperm nuclei obtained by sonication or mechanical agitation of freshly isolated sperm in the presence of anionic detergent were purified through a sucrose gradient and stained with acridine orange (AO); their fluorescence intensity was measured by flow cytometry. The green fluorescence, characteristic of AO binding to DNA by intercalation, was twice lower per unit of DNA for human sperm nuclei than for human peripheral blood lymphocytes. After extraction of basic proteins with 0.08 N HCl, AO binding to DNA increased 3.2-fold for lymphocytes and only 1.3-fold for sperm indicating that, in contrast to somatic cells, the proteins restricting AO binding to DNA are essentially non-extractable from sperm at that low pH. Treatment of human and mouse nuclei with dithiothreitol (DTT), a sulfhydryl reducing agent, and trypsin, removed constraints responsible for the restriction of AO binding. Specifically, as a result of DTT treatment alone there was up to a 20–30% increase of AO binding; upon subsequent addition of trypsin there was a further rapid rise in AO binding up to a final level of approximately 5 times the original AO binding to isolated sperm nuclei. Electron microscopy of DTT-treated human sperm nuclei showed that the reducing agent caused chromatin decondensation to a level whereby 20–30 A diameter fibers interconnecting chromatin bodies about 30–75 nm in diameter were revealed. Trypsin digestion in the presence of DTT converted the chromatin bodies into a network of fibrous structures about 150 A in diameter. Both electron microscopy and flow cytometry demonstrated an extremely large intercellular variation among human sperm nuclei in response to DTT and trypsin treatment indicating heterogeneity of chromatin structure. In contrast, AO staining of mouse sperm nuclei increased homogeneously in response to DTT and trypsin treatment.

Sperm transfer and storage in the lizard, Anolis carolinensis.

Abstract: The relationship of the hemipenis to the cloaca in copula and sperm storage and transport in the female oviduct were studied in Anolis carolinensis using light and scanning electron microscopy. During copulation, the hemipenis does not penetrate beyond the cloaca, but the two apical openings of the bifurcate sulcus spermaticus appose the openings of the oviducts from the cloaca. Sperm enter the sperm storage tubules between 2 and 6 hr after insemination and small amounts of sperm reach the infundibulum 6 to 24 hr following mating. Sperm storage tubules are embedded in the wall of the utero-vaginal transition, and are formed by the folding and fusion of the oviducal epithelium. The importance of the hemipenile-cloacal relationship and the role of sperm storage in the life history of A. carolinensis are discussed.

Initiation, prolongation, and reactivation of the motility of salmonid spermatozoa

Abstract: The motility of salmonid spermatozoa initiated by dilution of the milt with ovarian fluid or isotonic saline is brief duration; it was believed that it can be activated only once in the life of the spermatozoon. Dilution of the milt with an equal volume of isotonic saline (0.12 M-NaCl) containing 5 mM-3-isobutyl-1-methylxanthine (MIX) prolonged and intensified sperm motiliy. When motility had stopped after initial mobilization with saline or ovarian fluid, it could be reactivated by addition of MIX; reactivated spermatozoa fertilized eggs. Dilution with saline containing K+ (24 mEq/liter) did not initiate sperm motility even in the presence of MIX. The spermatozoa were mobilized by subsequent with 0.12 M-NaCl. The concentration of adenosine triphosphate (ATP) in sperm suspensions dropped on dilution with saline and rose as motility ceased, but declined without subsequent recovery following dilution with MIX-saline. The concentration of cyclic adenosine monophosphate (cAMP) rose and fell sharply on initiation of motility and rose again after motility had declined. While salmonid spermatozoa can be mobilized by dilition with saline alone, the effectiveness of MIX in reactivating “spent” spermatozoa supports the assumption that cAMP plays a role in the initiation of sperm motility.