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Sample records for enhancing sperm competitiveness

  1. Sperm form and function in the absence of sperm competition.

    Science.gov (United States)

    van der Horst, Gerhard; Maree, Liana

    2014-03-01

    Sperm competition is a post-copulatory, sexual selection force that, together with phylogeny and fertilization mode, has been regarded as one of the main factors explaining the diversity in sperm size across species. This universal sperm selection mechanism favors traits that enhance a male's fertilizing ability and paternity success. Surprisingly, however, sperm characteristics and semen quality in monogamous species, with low risk of sperm competition, have barely received any attention. In this review, we consider sperm competition and monogamy as two ends of the selective spectrum, and discuss its effect on sperm structure and function. We address the issue of a lack of sperm competition by comparing sperm traits of essentially monogamous species--their largely degenerative sperm features and high degree of polymorphisms could be norms for monogamous species. Further, the level of sperm competition in humans is discussed by comparing its mating strategy, relative testis size, and sperm traits to other primate species. In terms of sperm concentration, sperm swimming speed, and sperm morphology, humans seem to be closer aligned to the low-risk sperm competition situation in gorillas than to promiscuous chimpanzees. © 2013 Wiley Periodicals, Inc.

  2. Sperm competition, sperm numbers and sperm quality in muroid rodents.

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    Laura Gómez Montoto

    Full Text Available Sperm competition favors increases in relative testes mass and production efficiency, and changes in sperm phenotype that result in faster swimming speeds. However, little is known about its effects on traits that contribute to determine the quality of a whole ejaculate (i.e., proportion of motile, viable, morphologically normal and acrosome intact sperm and that are key determinants of fertilization success. Two competing hypotheses lead to alternative predictions: (a sperm quantity and quality traits co-evolve under sperm competition because they play complementary roles in determining ejaculate's competitive ability, or (b energetic constraints force trade-offs between traits depending on their relevance in providing a competitive advantage. We examined relationships between sperm competition levels, sperm quantity, and traits that determine ejaculate quality, in a comparative study of 18 rodent species using phylogenetically controlled analyses. Total sperm numbers were positively correlated to proportions of normal sperm, acrosome integrity and motile sperm; the latter three were also significantly related among themselves, suggesting no trade-offs between traits. In addition, testes mass corrected for body mass (i.e., relative testes mass, showed a strong association with sperm numbers, and positive significant associations with all sperm traits that determine ejaculate quality with the exception of live sperm. An "overall sperm quality" parameter obtained by principal component analysis (which explained 85% of the variance was more strongly associated with relative testes mass than any individual quality trait. Overall sperm quality was as strongly associated with relative testes mass as sperm numbers. Thus, sperm quality traits improve under sperm competition in an integrated manner suggesting that a combination of all traits is what makes ejaculates more competitive. In evolutionary terms this implies that a complex network of genetic

  3. Experimental evolution of sperm competitiveness in a mammal

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    Simmons Leigh W

    2011-01-01

    Full Text Available Abstract Background When females mate with multiple partners, sperm from rival males compete to fertilise the ova. Studies of experimental evolution have proven the selective action of sperm competition on male reproductive traits. However, while reproductive traits may evolve in response to sperm competition, this does not necessarily provide evidence that sperm competitive ability responds to selection. Indeed, a study of Drosophila failed to observe divergence in sperm competitive ability of males in lines selected for enhanced sperm offence and defence. Results Adopting the naturally polygamous house mouse (Mus domesticus as our vertebrate model, we performed an experimental evolution study and observed genetic divergence in sperm quality; males from the polygamous selection lines produced ejaculates with increased sperm numbers and greater sperm motility compared to males from the monogamous lines. Here, after 12 generations of experimental evolution, we conducted competitive matings between males from lineages evolving under sperm competition and males from lineages subject to relaxed selection. We reduced variation in paternity arising from embryo mortality by genotyping embryos in utero at 14 days gestation. Our microsatellite data revealed a significant paternity bias toward males that evolved under the selective regime of sperm competition. Conclusion We provide evidence that the sperm competitiveness phenotype can respond to selection, and show that improved sperm quality translates to greater competitive fertilisation success in house mice.

  4. Mass-specific metabolic rate and sperm competition determine sperm size in marsupial mammals.

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    Maximiliano Tourmente

    Full Text Available Two complementary hypotheses have been proposed to explain variation in sperm size. The first proposes that post-copulatory sexual selection favors an increase in sperm size because it enhances sperm swimming speed, which is an important determinant of fertilization success in competitive contexts. The second hypothesis proposes that mass-specific metabolic rate acts as a constraint, because large animals with low mass-specific metabolic rates will not be able to process resources at the rates needed to produce large sperm. This constraint is expected to be particularly pronounced among mammals, given that this group contains some of the largest species on Earth. We tested these hypotheses among marsupials, a group in which mass-specific metabolic rates are roughly 30% lower than those of eutherian mammals of similar size, leading to the expectation that metabolic rate should be a major constraint. Our findings support both hypotheses because levels of sperm competition are associated with increases in sperm size, but low mass-specific metabolic rate constrains sperm size among large species. We also found that the relationship between sperm size and mass-specific metabolic rate is steeper among marsupials and shallower among eutherian mammals. This finding has two implications: marsupials respond to changes in mass-specific metabolic rate by modifying sperm length to a greater extent, suggesting that they are more constrained by metabolic rate. In addition, for any given mass-specific metabolic rate, marsupials produce longer sperm. We suggest that this is the consequence of marsupials diverting resources away from sperm numbers and into sperm size, due to their efficient sperm transport along the female tract and the existence of mechanisms to protect sperm.

  5. Mass-specific metabolic rate and sperm competition determine sperm size in marsupial mammals.

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    Tourmente, Maximiliano; Gomendio, Montserrat; Roldan, Eduardo R S

    2011-01-01

    Two complementary hypotheses have been proposed to explain variation in sperm size. The first proposes that post-copulatory sexual selection favors an increase in sperm size because it enhances sperm swimming speed, which is an important determinant of fertilization success in competitive contexts. The second hypothesis proposes that mass-specific metabolic rate acts as a constraint, because large animals with low mass-specific metabolic rates will not be able to process resources at the rates needed to produce large sperm. This constraint is expected to be particularly pronounced among mammals, given that this group contains some of the largest species on Earth. We tested these hypotheses among marsupials, a group in which mass-specific metabolic rates are roughly 30% lower than those of eutherian mammals of similar size, leading to the expectation that metabolic rate should be a major constraint. Our findings support both hypotheses because levels of sperm competition are associated with increases in sperm size, but low mass-specific metabolic rate constrains sperm size among large species. We also found that the relationship between sperm size and mass-specific metabolic rate is steeper among marsupials and shallower among eutherian mammals. This finding has two implications: marsupials respond to changes in mass-specific metabolic rate by modifying sperm length to a greater extent, suggesting that they are more constrained by metabolic rate. In addition, for any given mass-specific metabolic rate, marsupials produce longer sperm. We suggest that this is the consequence of marsupials diverting resources away from sperm numbers and into sperm size, due to their efficient sperm transport along the female tract and the existence of mechanisms to protect sperm.

  6. Differences in the fatty-acid composition of rodent spermatozoa are associated to levels of sperm competition

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    delBarco-Trillo, Javier; Mateo, Rafael; Roldan, Eduardo R. S.

    2015-01-01

    Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation) and damage to the membrane. We hypothesized that in those species experiencing high levels of sperm competition there are changes in the fatty-acid composition of the sperm membrane that makes the membrane more resistant to oxidative damage. Given that polyunsaturated fatty acids (PUFAs) are the most prone to lipid peroxidation, we predicted that higher sperm competition leads to a reduction in the proportion of sperm PUFAs. In contrast, we predicted that levels of sperm competition should not affect the proportion of PUFAs in somatic cells. To test these predictions, we quantified the fatty-acid composition of sperm, testis and liver cells in four mouse species (genus Mus) that differ in their levels of sperm competition. Fatty-acid composition in testis and liver cells was not associated to sperm competition levels. However, in sperm cells, as predicted, an increase in sperm competition levels was associated with an increase in the proportion of saturated fatty-acids (the most resistant to lipid peroxidation) and by a concomitant decrease in the proportion of PUFAs. Two particular fatty acids were most responsible for this pattern (arachidonic acid and palmitic acid). Our findings thus indicate that sperm competition has a pervasive influence in the composition of sperm cells that ultimately may have important effects in sperm function. PMID:25795911

  7. Comparative evidence for the evolution of sperm swimming speed by sperm competition and female sperm storage duration in passerine birds.

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    Kleven, Oddmund; Fossøy, Frode; Laskemoen, Terje; Robertson, Raleigh J; Rudolfsen, Geir; Lifjeld, Jan T

    2009-09-01

    Sperm swimming speed is an important determinant of male fertility and sperm competitiveness. Despite its fundamental biological importance, the underlying evolutionary processes affecting this male reproductive trait are poorly understood. Using a comparative approach in a phylogenetic framework, we tested the predictions that sperm swim faster with (1) increased risk of sperm competition, (2) shorter duration of female sperm storage, and (3) increased sperm length. We recorded sperm swimming speed in 42 North American and European free-living passerine bird species, representing 35 genera and 16 families. We found that sperm swimming speed was positively related to the frequency of extrapair paternity (a proxy for the risk of sperm competition) and negatively associated with clutch size (a proxy for the duration of female sperm storage). Sperm swimming speed was unrelated to sperm length, although sperm length also increased with the frequency of extrapair paternity. These results suggest that sperm swimming speed and sperm length are not closely associated traits and evolve independently in response to sperm competition in passerine birds. Our findings emphasize the significance of both sperm competition and female sperm storage duration as evolutionary forces driving sperm swimming speed.

  8. Relative testis size and sperm morphometry across mammals: no evidence for an association between sperm competition and sperm length.

    OpenAIRE

    Gage, Matthew J G; Freckleton, Robert P

    2003-01-01

    Understanding why there is extensive variation in sperm form and function across taxa has been a challenge because sperm are specialized cells operating at a microscopic level in a complex environment. This comparative study collates published data to determine whether the evolution of sperm morphometry (sperm total length and separate component dimensions) is associated with sperm competition (when different males' sperm mix and compete for a female's ova) across 83 mammalian species. We use...

  9. No evidence for sperm priming responses under varying sperm competition risk or intensity in guppies

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    Evans, Jonathan P.

    2009-07-01

    Sperm competition theory predicts that males should tailor their investment in ejaculates according to the number of rival males competing to fertilize a female’s eggs. Research spanning several taxa supports this prediction by showing that males are often sensitive to the level of sperm competition and adjust their investment in sperm numbers accordingly. More recent work has revealed that males may also tailor the quality of sperm according to the number of males competing for fertilization. Here I test for both effects in guppies ( Poecilia reticulata) in an experiment that simultaneously evaluates the risk and intensity models of sperm competition. The experiment determined whether male guppies adjust the number (stripped ejaculate size) and quality (sperm velocity and viability) of sperm that are primed over a 3-day period according to experimental changes in the perceived level of sperm competition. A total of 136 focal males were initially stripped of all retrievable sperm and assayed for these sperm traits before being allocated at random to one of four treatments simulating different levels of sperm competition risk and intensity. During the 3-day treatment phase, focal males had visual and olfactory access to a sexually receptive (initially virgin) female maintained with different numbers of stimulus males to simulate variation in the risk and intensity of sperm competition. Following this, males were assayed again for the sperm traits. Contrary to predictions, there was no significant change in any of the measured variables among treatments, although qualitatively the patterns for sperm velocity and viability did conform to expectation. The lack of any trend for the number of sperm primed was unequivocal and future work examining the effects of sperm competition on sperm production should focus on whether males differentially allocate sperm numbers among matings that differ in the level of sperm competition.

  10. Sperm competition and reproductive mode influence sperm dimensions and structure among snakes.

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    Tourmente, Maximiliano; Gomendio, Montserrat; Roldan, Eduardo R S; Giojalas, Laura C; Chiaraviglio, Margarita

    2009-10-01

    The role of sperm competition in increasing sperm length is a controversial issue, because findings from different taxa seem contradictory. We present a comparative study of 25 species of snakes with different levels of sperm competition to test whether it influences the size and structure of different sperm components. We show that, as levels of sperm competition increase, so does sperm length, and that this elongation is largely explained by increases in midpiece length. In snakes, the midpiece is comparatively large and it contains structures, which in other taxa are present in the rest of the flagellum, suggesting that it may integrate some of its functions. Thus, increases in sperm midpiece size would result in more energy as well as greater propulsion force. Sperm competition also increases the area occupied by the fibrous sheath and outer dense fibers within the sperm midpiece, revealing for the first time an effect upon structural elements within the sperm. Finally, differences in male-male encounter rates between oviparous and viviparous species seem to lead to differences in levels of sperm competition. We conclude that the influence of sperm competition upon different sperm components varies between taxa, because their structure and function is different.

  11. Variability in sperm form and function in the context of sperm competition risk in two Tupinambis lizards

    OpenAIRE

    Blengini, Cecilia S; Sergio, Naretto; Gabriela, Cardozo; Giojalas, Laura C; Margarita, Chiaraviglio

    2014-01-01

    In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect is still poorly understood. It has been suggested that an increase in sperm competition pressure could reduce sperm size variation or produce a diversity of sperm to maximize male fertilization success. We aim at elucidating the variability of sperm morphometric traits and v...

  12. Phenotypic engineering of sperm-production rate confirms evolutionary predictions of sperm competition theory.

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    Sekii, Kiyono; Vizoso, Dita B; Kuales, Georg; De Mulder, Katrien; Ladurner, Peter; Schärer, Lukas

    2013-04-22

    Sperm production is a key male reproductive trait and an important parameter in sperm competition theory. Under sperm competition, paternity success is predicted to depend strongly on male allocation to sperm production. Furthermore, because sperm production is inherently costly, individuals should economize in sperm expenditure, and conditional adjustment of the copulation frequency according to their sperm availability may be expected. However, experimental studies showing effects of sperm production on mating behaviour and paternity success have so far been scarce, mainly because sperm production is difficult to manipulate directly in animals. Here, we used phenotypic engineering to manipulate sperm-production rate, by employing dose-dependent RNA interference (RNAi) of a spermatogenesis-specific gene, macbol1, in the free-living flatworm Macrostomum lignano. We demonstrate (i) that our novel dose-dependent RNAi approach allows us to induce high variability in sperm-production rate; (ii) that a reduced sperm-production rate is associated with a decreased copulation frequency, suggesting conditional adjustment of mating behaviour; and (iii) that both sperm production and copulation frequency are important determinants of paternity success in a competitive situation, as predicted by sperm competition theory. Our study clearly documents the potential of phenotypic engineering via dose-dependent RNAi to test quantitative predictions of evolutionary theory.

  13. COMP-1 promotes competitive advantage of nematode sperm.

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    Hansen, Jody M; Chavez, Daniela R; Stanfield, Gillian M

    2015-03-19

    Competition among sperm to fertilize oocytes is a ubiquitous feature of sexual reproduction as well as a profoundly important aspect of sexual selection. However, little is known about the cellular mechanisms sperm use to gain competitive advantage or how these mechanisms are regulated genetically. In this study, we utilize a forward genetic screen in Caenorhabditis elegans to identify a gene, comp-1, whose function is specifically required in competitive contexts. We show that comp-1 functions in sperm to modulate their migration through and localization within the reproductive tract, thereby promoting their access to oocytes. Contrary to previously described models, comp-1 mutant sperm show no defects in size or velocity, thereby defining a novel pathway for preferential usage. Our results indicate not only that sperm functional traits can influence the outcome of sperm competition, but also that these traits can be modulated in a context-dependent manner depending on the presence of competing sperm.

  14. Differences in the fatty-acid composition of rodent spermatozoa are associated to levels of sperm competition

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    Javier delBarco-Trillo

    2015-03-01

    Full Text Available Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation and damage to the membrane. We hypothesized that in those species experiencing high levels of sperm competition there are changes in the fatty-acid composition of the sperm membrane that makes the membrane more resistant to oxidative damage. Given that polyunsaturated fatty acids (PUFAs are the most prone to lipid peroxidation, we predicted that higher sperm competition leads to a reduction in the proportion of sperm PUFAs. In contrast, we predicted that levels of sperm competition should not affect the proportion of PUFAs in somatic cells. To test these predictions, we quantified the fatty-acid composition of sperm, testis and liver cells in four mouse species (genus Mus that differ in their levels of sperm competition. Fatty-acid composition in testis and liver cells was not associated to sperm competition levels. However, in sperm cells, as predicted, an increase in sperm competition levels was associated with an increase in the proportion of saturated fatty-acids (the most resistant to lipid peroxidation and by a concomitant decrease in the proportion of PUFAs. Two particular fatty acids were most responsible for this pattern (arachidonic acid and palmitic acid. Our findings thus indicate that sperm competition has a pervasive influence in the composition of sperm cells that ultimately may have important effects in sperm function.

  15. Intraspecific variation in sperm length is negatively related to sperm competition in passerine birds.

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    Kleven, Oddmund; Laskemoen, Terje; Fossøy, Frode; Robertson, Raleigh J; Lifjeld, Jan T

    2008-02-01

    Spermatozoa are among the most diversified cells in the animal kingdom, but the underlying evolutionary forces affecting intraspecific variation in sperm morphology are poorly understood. It has been hypothesized that sperm competition is a potent selection pressure on sperm variation within species. Here, we examine intraspecific variation in total sperm length of 22 wild passerine bird species (21 genera, 11 families) in relation to the risk of sperm competition, as expressed by the frequency of extrapair paternity and relative testis size. We demonstrate, by using phylogenetic comparative methods, that between-male variation in sperm length within species is closely and negatively linked to the risk of sperm competition. This relationship was even stronger when only considering species in which data on sperm length and extrapair paternity originated from the same populations. Intramale variation in sperm length within species was also negatively, although nonsignificantly, related to sperm competition risk. Our findings suggest that postcopulatory sexual selection is a powerful evolutionary force reducing the intraspecific phenotypic variation in sperm-size traits, potentially driving the diversification of sperm morphology across populations and species.

  16. Sperm competition promotes diversity of sperm bundles in Ohomopterus ground beetles

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    Takami, Yasuoki; Sota, Teiji

    2007-07-01

    Diversification of sperm morphology has been investigated in the context of sperm competition, but the adaptive significance of sperm bundles is still unclear. In analyzing 10 taxa of the genus Carabus subgenus Ohomopterus and one related Carabus ground beetles, we found that dimorphic sperm bundles occurred in most species with varied degrees of bimodality, whereas sperm were generally monomorphic. Comparative analyses with phylogenetically independent contrasts revealed that the sizes of large and small sperm bundles evolved more rapidly than, and were not correlated with, the length of sperm, suggesting more intense selection on sperm bundle sizes and their independent responses to different evolutionary forces. The size of large sperm bundles was positively correlated with male genital morphology (pertinent to displacement of rival spermatophores) and postcopulatory guarding duration as well as male body length, suggesting that larger sperm bundles have been favored when the risk of spermatophore displacement is high. Larger sperm bundles may be advantageous because of their ability to migrate more rapidly into the spermatheca. In contrast, no clear association was detected between the small sperm bundle size and mating traits despite its rapid diversification. The present study provides the first record of heteromorphic sperm bundles, the diversity of which may be promoted by sperm competition.

  17. Increased competitiveness of nematode sperm bearing the male X chromosome.

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    LaMunyon, C W; Ward, S

    1997-01-07

    Male offspring, which cannot reproduce independently, represent a cost of sexual reproduction. This cost is eliminated by the production of hermaphroditic offspring in the self-fertilizing nematode Caenorhabditis briggsae. However, these hermaphrodites can outcross by mating with males. Half the sperm received from males contain no sex chromosome and therefore give rise to male progeny. Mating with males should thus impose the cost of making male offspring. We found that male sperm took immediate precedence over hermaphrodite sperm, resulting in maximized outcrossing, but the appearance of male progeny was delayed after mating. This delay is caused by the male X-bearing sperm outcompeting their nullo-X counterparts. The competitive advantage of X-bearing sperm over nullo-X sperm is limited to sperm from males; it did not occur in a mutant hermaphrodite that produces both types of sperm. The chromosomal effect on sperm competitiveness in C. briggsae, which has not been observed in other species, suggests that the X chromosome has evolved a form of meiotic drive, selfishly increasing the competitiveness of sperm that bear it over those that do not. Thus, the multiple levels of sperm competitiveness found in C. briggsae maximize outcrossing after mating while delaying the cost of making male offspring.

  18. A sperm competition model for the European bitterling (Rhodeus amarus)

    Czech Academy of Sciences Publication Activity Database

    Smith, Carl; Reichard, Martin

    2013-01-01

    Roč. 150, č. 14 (2013), s. 1709-1730 ISSN 0005-7959 R&D Projects: GA ČR GA206/09/1163 Institutional support: RVO:68081766 Keywords : Acheilognathinae * alternative mating tactics * mating system * sneaking * sperm competition * sperm motility Subject RIV: EG - Zoology Impact factor: 1.401, year: 2013

  19. Variation in sperm morphometry and sperm competition among barn swallow (Hirundo rustica) populations

    Czech Academy of Sciences Publication Activity Database

    Laskemoen, T.; Albrecht, Tomáš; Bonisoli-Alquati, A.; Cepák, J.; De Lope, F.; Hermosell, I. G.; Johannessen, L. E.; Kleven, O.; Marzal, A.; Mousseau, T. A.; Moller, A. P.; Robertson, R. J.; Rudolfsen, G.; Saino, N.; Vortman, Y.; Lifjeld, J. T.

    2013-01-01

    Roč. 67, č. 2 (2013), s. 301-309 ISSN 0340-5443 R&D Projects: GA ČR(CZ) GAP506/12/2472 Institutional support: RVO:68081766 Keywords : Barn swallow * Extrapair paternity * Hirundo rustica * Sperm competition * Sperm size Subject RIV: EG - Zoology Impact factor: 3.049, year: 2013

  20. Sperm depletion as a consequence of increased sperm competition risk in the European bitterling, Rhodeus amarus

    Czech Academy of Sciences Publication Activity Database

    Smith, C.; Pateman-Jones, C.; Zieba, G.; Przybylski, M.; Reichard, Martin

    2009-01-01

    Roč. 77, č. 5 (2009), s. 1227-1233 ISSN 0003-3472 Institutional research plan: CEZ:AV0Z60930519 Keywords : alternative mating tactics * European bitterling * mating system * sexual conflict * sexual selection * sneaking * sperm competition * sperm economy Subject RIV: EG - Zoology Impact factor: 2.890, year: 2009

  1. Sperm competition-induced plasticity in the speed of spermatogenesis.

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    Giannakara, Athina; Schärer, Lukas; Ramm, Steven A

    2016-03-08

    Sperm competition between rival ejaculates over the fertilization of ova typically selects for the production of large numbers of sperm. An obvious way to increase sperm production is to increase testis size, and most empirical work has focussed on this parameter. Adaptive plasticity in sperm production rate could also arise due to variation in the speed with which each spermatozoon is produced, but whether animals can respond to relevant environmental conditions by modulating the kinetics of spermatogenesis in this way has not been experimentally investigated. Here we demonstrate that the simultaneously hermaphroditic flatworm Macrostomum lignano exhibits substantial plasticity in the speed of spermatogenesis, depending on the social context: worms raised under higher levels of sperm competition produce sperm faster. Our findings overturn the prevailing view that the speed of spermatogenesis is a static property of a genotype, and demonstrate the profound impact that social environmental conditions can exert upon a key developmental process. We thus identify, to our knowledge, a novel mechanism through which sperm production rate is maximised under sperm competition.

  2. Male spiders reduce pre- and postmating sexual investment in response to sperm competition risk

    DEFF Research Database (Denmark)

    Tuni, Cristina; Weber, Sabrina; Bilde, Trine

    2017-01-01

    to a competitor by altering: 1) premating investment in the gift, 2) postmating sperm investment, and 3) whether pre- and postmating responses are coupled and respond to competition in the same direction or not. Under competition risk males silk-wrapped their gifts for significantly shorter time and transferred......The interplay between pre- and postmating responses to intrasexual competition remains enigmatic. Sperm competition models often assume a trade-off between pre- and postmating traits that enhance mate acquisition and fertilization success, respectively. However, when males court females through...... food donations (i.e., nuptial gifts), pre- and postmating responses may be aligned, as nuptial gifts have the dual function of facilitating both mate acquisition and sperm transfer. In the spider Pisaura mirabilis, nuptial gifts consist of silk-wrapped prey. We tested whether males respond...

  3. Evolutionary Modeling Predicts a Decrease in Postcopulatory Sperm Viability as a Response to Increasing Levels of Sperm Competition

    NARCIS (Netherlands)

    Engqvist, Leif

    Sperm competition has been found to have a strong influence on the evolution of many male and female reproductive traits. Theoretical models have shown that, with increasing levels of sperm competition, males are predicted to increase ejaculate investment, and there is ample empirical evidence

  4. By hook or by crook? Morphometry, competition and cooperation in rodent sperm.

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    Simone Immler

    Full Text Available BACKGROUND: Sperm design varies enormously across species and sperm competition is thought to be a major factor influencing this variation. However, the functional significance of many sperm traits is still poorly understood. The sperm of most murid rodents are characterised by an apical hook of the sperm head that varies markedly in extent across species. In the European woodmouse Apodemus sylvaticus (Muridae, the highly reflected apical hook of sperm is used to form sperm groups, or "trains," which exhibited increased swimming velocity and thrusting force compared to individual sperm. METHODOLOGY/PRINCIPAL FINDINGS: Here we use a comparative study of murine rodent sperm and demonstrate that the apical hook and sperm cooperation are likely to be general adaptations to sperm competition in rodents. We found that species with relatively larger testes, and therefore more intense sperm competition, have a longer, more reflected apical sperm hook. In addition, we show that sperm groups also occur in rodents other than the European woodmouse. CONCLUSIONS: Our results suggest that in rodents sperm cooperation is more widespread than assumed so far and highlight the importance of diploid versus haploid selection in the evolution of sperm design and function.

  5. On sperm competition games: raffles and roles revisited.

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    Mesterton-Gibbons, M

    1999-08-01

    In principle there are two approaches to modelling a trade-off between the positive and negative outcomes of a behavior: after suitably defining a value for the behavior in the absence of any trade-off, one can either multiply that value by an appropriate discount or subtract an appropriate cost. In a prospective analysis of sperm competition, Parker (Proc. Roy. Soc. Lond. B (1990) 242, 120-126) adopted the multiplicative approach to model the trade-off between the value of a mating and the cost of its acquisition. He obtained two paradoxical results. First, if two males 'know' whether they are first or second to mate, but these roles are assigned randomly, then sperm numbers should be the same for both males whether the 'raffle' for fertilization is fair or unfair. Second, if mating order is constant, then a favored male should expend less on sperm. His results are puzzling not only in terms of intuition about nature, but also in terms of his model's consistency. In other words, they present both an external and an internal paradox. Parker assumed the fairness of the raffle to a disfavored male to be independent of how much sperm a favored male deposits. This article both generalizes Parker's analysis by allowing fairness to decrease with sperm expenditure by the favored male and compares Parker's results to those obtained by the additive approach. In many respects, results are similar. Nevertheless, if the costs of mating are assumed to increase with sperm expenditure but not to depend on the role in which sperm is expended, as Parker assumed, then the additive approach is more fundamentally correct. In particular, Parker's constant-role paradox is an artifact of his approach. His random-role paradox is internally rationalized in terms of standard microeconomic theory. When fairness decreases, however slightly, with sperm expenditure by the favored male, both models demonstrate that the evolutionarily stable strategy is for more sperm to be deposited during a

  6. Ovarian fluid of receptive females enhances sperm velocity

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    Gasparini, Clelia; Andreatta, Gabriele; Pilastro, Andrea

    2012-05-01

    The females of several internal fertilizers are able to store sperm for a long time, reducing the risk of sperm limitation. However, it also means that males can attempt to mate outside females' receptive period, potentially increasing the level of sperm competition and exacerbating sexual conflict over mating. The guppy ( Poecilia reticulata), an internally fertilizing fish, is a model system of such competition and conflict. Female guppies accept courtship and mate consensually only during receptive periods of the ovarian cycle but receive approximately one (mostly forced) mating attempt per minute both during and outside their sexually receptive phase. In addition, females can store viable sperm for months. We expected that guppy females would disfavour sperm received during their unreceptive period, possibly by modulating the quality and/or quantity of the components present in the ovarian fluid (OF) over the breeding cycle. Ovarian fluid has been shown to affect sperm velocity, a determinant of sperm competition success in this and other fishes. We found that in vitro sperm velocity is slower in OF collected from unreceptive females than in OF from receptive females. Visual stimulation with a potential partner prior to collection did not significantly affect in vitro sperm velocity. These results suggest that sperm received by unreceptive females may be disfavoured as sperm velocity likely affects the migration process and the number of sperm that reach storage sites.

  7. Sperm competitive ability and indices of lifetime reproductive success.

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    Fricke, Claudia; Martin, Oliver Y; Bretman, Amanda; Bussière, Luc F; Chapman, Tracey

    2010-09-01

    Understanding the selection pressures shaping components of male reproductive success is essential for assessing the role of sexual selection on phenotypic evolution. A male's competitive reproductive success is often measured in sequential mating tests by recording P1 (first mating male) and P2 (second mating male) paternity scores. How each of these scores relates to a male's overall fitness, for example, lifetime reproductive success is, however, not known. This information is needed to determine whether males benefit from maximizing both P1 and P2 or by trading off P1 against P2 ability. We measured P1, P2, and an index of lifetime reproductive success (LRS(i) , a male's competitive reproductive success measured over 12 days) for individual male Drosophila melanogaster. We found no evidence for phenotypic correlations between P1 and P2. In addition, whereas both P1 and P2 were associated with relative LRS(i) , only P2 predicted absolute LRS(i) . The results suggest that P2 was most closely linked to LRS(i) in the wild-type population studied, a finding which may be common to species with strong second male sperm precedence. The study illustrates how P1 and P2 can have differing relationships with a male's overall reproductive success, and highlights the importance of understanding commonly used measures of sperm competition in the currency of fitness. © 2010 The Author(s). Journal compilation © 2010 The Society for the Study of Evolution.

  8. Sexual selection, germline mutation rate and sperm competition.

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    Møller, A P; Cuervo, J J

    2003-04-18

    An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1) Increased sperm production associated with sperm competition may increase mutation rate. (2) Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection. A comparative study of birds revealed a positive correlation between mutation rate at minisatellite loci and extra-pair paternity, but not between mutation rate and relative testes mass which is a measure of relative sperm production. Minisatellite mutation rates were not related to longevity, suggesting a meiotic rather than a mitotic origin of mutations. We found evidence of increased mutation rate in species with more intense sexual selection. Increased mutation was not associated with increased sperm production, and we suggest that species with intense sexual selection may maintain elevated mutation rates because sexual selection continuously benefits viability alleles expressed in condition

  9. Sexual selection, germline mutation rate and sperm competition

    Directory of Open Access Journals (Sweden)

    Møller AP

    2003-04-01

    Full Text Available Abstract Background An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1 Increased sperm production associated with sperm competition may increase mutation rate. (2 Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection. Results A comparative study of birds revealed a positive correlation between mutation rate at minisatellite loci and extra-pair paternity, but not between mutation rate and relative testes mass which is a measure of relative sperm production. Minisatellite mutation rates were not related to longevity, suggesting a meiotic rather than a mitotic origin of mutations. Conclusion We found evidence of increased mutation rate in species with more intense sexual selection. Increased mutation was not associated with increased sperm production, and we suggest that species with intense sexual selection may maintain elevated mutation rates because sexual selection continuously

  10. On the relative effect of spawning asynchrony, sperm quantity and sperm quality on paternity under sperm competition in an external fertilizer

    Directory of Open Access Journals (Sweden)

    Torvald Blikra Egeland

    2015-07-01

    Full Text Available How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker males, which often spawn out of synchrony with the female, produce more and faster sperm than the guarding males. We used controlled in vitro fertilization trials with experimentally produced dominant and subordinate, sneaker males to test what effect relative synchrony in gamete release, sperm quality (i.e., motility and velocity and sperm quantity have on a male’s fertilization success in pair-wise sperm competitions. When the sneaker males released ejaculates after the guarding male there was no overall difference in fertilization success. The quality (i.e., motility and velocity of a male’s sperm relative to that of the competing male was the best predictor of male fertilization success regardless of their mating tactic and spawning synchrony. The relative number of sperm cells also had an effect on fertilization success, but mainly when the dominant and sneaker male ejaculated synchronously. Our close imitation of natural sperm competition in charr shows that the sneaker males of external fertilizing species may fully compensate for their disadvantaged mating role by producing ejaculates of higher quality - an adjustment strangely not met by dominants.

  11. Sperm competition selects beyond relative testes size in birds

    OpenAIRE

    Lüpold S; Linz GM; Rivers JW; Westneat DF; Birkhead TR

    2009-01-01

    Sperm morphology varies considerably across taxa and postcopulatory sexual selection is thought to be one of the main forces responsible for this diversity. Several studies have investigated the effects of the variation in sperm design on sperm function but the consequences of variation in sperm design on testis morphology have been overlooked. Testes size or architecture may determine the size of the sperm they produce and selection for longer sperm may require concomitant adaptations in the...

  12. Sperm competition and the evolution of precopulatory weapons: Increasing male density promotes sperm competition and reduces selection on arm strength in a chorusing frog.

    Science.gov (United States)

    Buzatto, Bruno A; Roberts, J Dale; Simmons, Leigh W

    2015-10-01

    Sperm competition theory assumes a trade-off between precopulatory traits that increase mating success and postcopulatory traits that increase fertilization success. Predictions for how sperm competition might affect male expenditure on these traits depend on the number of competing males, the advantage gained from expenditure on weapons, and the level of sperm competition. However, empirical tests of sperm competition theory rarely examine precopulatory male expenditure. We investigated how variation in male density affects precopulatory sexual selection on male weaponry and the level of sperm competition in the chorusing frog Crinia georgiana, where males use their arms as weapons in male-male combat. We measured body size and arm girth of 439 males, and recorded their mating success in the field. We found density-dependent selection acting on arm girth. Arm girth was positively associated with mating success, but only at low population densities. Increased male density was associated with higher risk and intensity of sperm competition arising from multimale amplexus, and a reversal in the direction of selection on arm girth. Opposing patterns of pre- and postcopulatory selection may account for the negative covariation between arm girth and testes across populations of this species. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  13. Maternal effects, but no good or compatible genes for sperm competitiveness in Australian crickets.

    Science.gov (United States)

    Dowling, Damian K; Nystrand, Magdalena; Simmons, Leigh W

    2010-05-01

    Explanations for the evolution of polyandry often center on the idea that females garner genetic benefits for their offspring by mating multiply. Furthermore, postcopulatory processes are thought to be fundamental to enabling polyandrous females to screen for genetic quality. Much attention has focused on the potential for polyandrous females to accrue such benefits via a sexy- or good-sperm mechanism, whereby additive variation exists among males in sperm competitiveness. Likewise, attention has focused on an alternative model, in which offspring quality (in this context, the sperm competitiveness of sons) hinges on an interaction between parental haplotypes (genetic compatibility). Sperm competitiveness that is contingent on parental compatibility will exhibit nonadditive genetic variation. We tested these models in the Australian cricket, Teleogryllus oceanicus, using a design that allowed us to partition additive, nonadditive genetic, and parental variance for sperm competitiveness. We found an absence of additive and nonadditive genetic variance in this species, challenging the direct relevance of either model to the evolution of sperm competitiveness in particular, and polyandry in general. Instead, we found maternal effects that were possibly sex-linked or cytoplasmically linked. We also found effects of focal male age on sperm competitiveness, with small increments in age conferring more competitive sperm.

  14. Sperm swimming velocity predicts competitive fertilization success in the green swordtail Xiphophorus helleri.

    Directory of Open Access Journals (Sweden)

    Clelia Gasparini

    Full Text Available Sperm competition is expected to favour the evolution of traits that influence the performance of sperm when they compete to fertilize a female's eggs. While there is considerable evidence that selection favours increases in sperm numbers, much less is known about how sperm quality contributes towards competitive fertilization success. Here, we determine whether variation in sperm quality influences competitive fertilization success in the green swordtail Xiphophorus helleri, a highly promiscuous livebearing fish. We use artificial insemination as a method of controlled sperm delivery and show that sperm swimming velocity is the primary determinant of fertilization success when ejaculates from two males compete to fertilize a female's eggs. By contrast, we found no evidence that sperm length had any effect on siring success. We also found no evidence that pre- and postcopulatory sexual traits were phenotypically integrated in this species, suggesting that the previous observation that reproductive skew favours males with high mating rates is unlikely to be due to any direct association between sperm quality and male sexual ornamentation.

  15. Sperm competition and sex allocation in simultaneous hermaphrodites : A new look at Charnov's invariance principle

    NARCIS (Netherlands)

    Pen, I.R.; Weissing, F.J.

    Recently, Charnov (1996) investigated the consequences of sperm competition for optimal sex allocation in simultaneous hermaphrodites. Charnov argued that the optimal sex allocation strategy can be derived on the basis of the 'sperm displacement rule'; that is, the function describing the

  16. High level of sperm competition may increase transfer of accessory gland products carried by the love dart of land snails.

    Science.gov (United States)

    Lodi, Monica; Staikou, Alexandra; Janssen, Ruben; Koene, Joris M

    2017-12-01

    Postcopulatory adaptations that increase reproductive success compared to rivals, like the transfer of accessory gland products that promote paternity, are common when sperm competition occurs among males. In land snails, the dart shooting behavior and its adaptive significance, in promoting individual fitness through enhanced paternity of the successful dart shooter, have been considered such an adaptation. The fitness result gained is mediated by the transfer of mucus components on the love dart capable of altering the physiology of the receiver's reproductive tract. In this context, dart shooting and mucus transfer could be considered as processes targeted by sexual selection. While the effect of dart mucus is beneficial for the dart user, so far it has remained unknown whether its transport is greater when snails experience a higher level of sperm competition. Here, we report results of a study on inter- and intraspecific variations of dart and mucus gland morphometry, considered to be traits reflecting the ability of snails to adjust the production and transfer of mucus under varying sperm competition scenarios. We investigated four populations with different densities from four dart-bearing species, Arianta arbustorum , Cepaea nemoralis , Cornu aspersum, and Helix lucorum . The results indicate that different adaptations of these traits occur among the studied species that all seem to achieve the same goal of transferring more mucus when sperm competition is higher. For example, the presence of longer and more branched mucous glands or an increase in dart surface most likely reflect increased mucus production and enhanced ability of mucus transport, respectively. Interestingly, the species for which the use of the dart is reported to be facultative, A. arbustorum , did not show any variation among the examined traits. To conclude, sexual selection in the form of sperm competition intensity seems to be an important selective force for these simultaneously

  17. Enhancement of Sexual Libido and Sperm Production in rabbits ...

    African Journals Online (AJOL)

    Enhancement of Sexual Libido and Sperm Production in rabbits using Clomiphene citrate (Clomid®) ... The results obtained in Trial II showed that sperm concentration was higher (P<0.05) in animals treated with 6.25mg of the drug than their counterparts treated with 12.50mg of the drug. The Chinchilla bucks were of higher ...

  18. Inbreeding depresses sperm competitiveness, but not fertilization or mating success in male Tribolium castaneum

    Science.gov (United States)

    Michalczyk, Łukasz; Martin, Oliver Y.; Millard, Anna L.; Emerson, Brent C.; Gage, Matthew J. G.

    2010-01-01

    As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male–male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P2 ‘offence’ role in sperm competition was significantly more depressed under inbreeding than sperm ‘defence’ (P1). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated. PMID:20554548

  19. Intraspecific sperm competition genes enforce post-mating species barriers in Drosophila.

    Science.gov (United States)

    Castillo, Dean M; Moyle, Leonie C

    2014-12-22

    Sexual selection and sexual conflict are considered important drivers of speciation, based on both theoretical models and empirical correlations between sexually selected traits and diversification. However, whether reproductive isolation between species evolves directly as a consequence of intrapopulation sexual dynamics remains empirically unresolved, in part because knowledge of the genetic mechanisms (if any) connecting these processes is limited. Here, we provide evidence of a direct mechanistic link between intraspecies sexual selection and reproductive isolation. We examined genes with known roles in intraspecific sperm competition (ISC) in D. melanogaster and assayed their impact on conspecific sperm precedence (CSP). We found that two such genes (Acp36DE and CG9997) contribute to both offensive sperm competition and CSP; null/knockdown lines both had lower competitive ability against D. melanogaster conspecifics and were no longer able to displace heterospecific D. simulans sperm in competitive matings. In comparison, Sex Peptide (Acp70A)-another locus essential for ISC-does not contribute to CSP. These data indicate that two loci important for sperm competitive interactions have an additional role in similar interactions that enforce post-mating reproductive isolation between species, and show that sexual selection and sexual isolation can act on the same molecular targets in a gene-specific manner. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  20. Enhancement of mouse sperm motility by trophinin-binding peptide

    Directory of Open Access Journals (Sweden)

    Park Seong

    2012-11-01

    Full Text Available Abstract Background Trophinin is an intrinsic membrane protein that forms a complex in the cytoplasm with bystin and tastin, linking it microtubule-associated motor dynein (ATPase in some cell types. Previously, we found that human sperm tails contain trophinin, bystin and tastin proteins, and that trophinin-binding GWRQ (glycine, tryptophan, arginine, glutamine peptide enhanced motility of human sperm. Methods Immunohistochemistry was employed to determine trophinin protein in mouse spermatozoa from wild type mouse, by using spermatozoa from trophinin null mutant mice as a negative control. Multivalent 8-branched GWRQ (glycine, tryptophan, arginine, glutamine peptide or GWRQ-MAPS, was chemically synthesized, purified by HPLC and its structure was confirmed by MALDI-TOF mass spectrometry. Effect of GWRQ-MAPS on mouse spermatozoa from wild type and trophinin null mutant was assessed by a computer-assisted semen analyzer (CASA. Results Anti-trophinin antibody stained the principal (central piece of the tail of wild type mouse sperm, whereas the antibody showed no staining on trophinin null sperm. Phage particles displaying GWRQ bound to the principal piece of sperm tail from wild type but not trophinin null mice. GWRQ-MAPS enhanced motility of spermatozoa from wild type but not trophinin null mice. CASA showed that GWRQ-MAPS enhanced both progressive motility and rapid motility in wild type mouse sperm. Conclusions Present study established the expression of trophinin in the mouse sperm tail and trophinin-dependent effect of GWRQ-MAPS on sperm motility. GWRQ causes a significant increase in sperm motility.

  1. The application of in vitro sperm competition test to evaluate the impact of ZP-derived peptides on fertilization capacity of cat sperm.

    Science.gov (United States)

    Niu, Yuyu; Greube, Alexa; Ji, Weizhi; Jewgenow, Katarina

    2006-09-01

    The present study aimed to establish a sensitive in vitro assay to assess the binding capacity of cat spermatozoa. Cat oocytes and epididymal sperm cells were isolated from gonads and cultured for in vitro fertilization. Before fertilization, the sperm cells were incubated either in 10 microM green dye Fluo-3-AM or 10 microM orange dye CellTracker Orange CMTMR (Molecular Probes), respectively. After removing the dyes by washing, sperm cells stained with each dye were added to medium drops containing oocytes in various proportions and cultured for 16 h at 37 degrees C, 5% CO(2). The oocytes were examined using fluorescence microscopy. Sperm bound to oocytes, and stained with different colors, were counted. When fresh epididymal sperm were mixed in at a specific proportion, the number of sperm bound to the zona pellucida (ZP) of oocytes reflected the proportion of differently colored sperm in the medium. This indicated that neither dye influenced the binding capacity of cat sperm. Mixing fresh and cryopreserved sperm, however, resulted in a higher number of fresh sperm bound to the oocyte surface in comparison to frozen-thawed sperm. Also, the pre-incubation of cat sperm cells with ZP derived peptide reduced the sperm binding capacity by 40%. In conclusion, the presented sperm competition assay allows assessment of fertilizing capacity of cat spermatozoa in vitro when a mixture of two different populations is used. The applied supravital fluorescence dyes do not affect motility and binding capacity of sperm cells and were clearly distinguishable under fluorescence microscopy. We demonstrate that the assay can be used to study the impact of sperm treatment, such as cryopreservation or pre-incubation in bioactive peptides, on fertilizing capacity.

  2. Rival male relatedness does not affect ejaculate allocation as predicted by sperm competition theory.

    Directory of Open Access Journals (Sweden)

    Melissa L Thomas

    Full Text Available When females are sexually promiscuous, the intensity of sperm competition for males depends on how many partners females mate with. To maximize fitness, males should adjust their copulatory investment in relation to this intensity. However, fitness costs associated with sperm competition may not only depend on how many males a female has mated with, but also how related rival males are. According to theoretical predictions, males should adjust their copulatory investment in response to the relatedness of their male rival, and transfer more sperm to females that have first mated with a non-sibling male than females that have mated to a related male. Here, for the first time, we empirically test this theory using the Australian field cricket Teleogryllus oceanicus. We expose male crickets to sperm competition from either a full sibling or non-sibling male, by using both the presence of a rival male and the rival male's actual competing ejaculate as cues. Contrary to predictions, we find that males do not adjust ejaculates in response to the relatedness of their male rival. Instead, males with both full-sibling and non-sibling rivals allocate sperm of similar quality to females. This lack of kin biased behaviour is independent of any potentially confounding effect of strong competition between close relatives; kin biased behaviour was absent irrespective of whether males were raised in full sibling or mixed relatedness groups.

  3. Honey bee males and queens use glandular secretions to enhance sperm viability before and after storage

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Boomsma, Jacobus Jan; Baer, Boris

    2009-01-01

    on sperm survival. After sperm storage, the queens also provide sperm with secretions from spermathecal glands and we show that these secretions have a comparable positive effect on sperm viability. SDS gels show that the proteomic profiles of accessory gland secretion and spermathecal fluid secretion...... hardly overlap, which suggests that males and females use different proteins to enhance sperm viability during, respectively, ejaculation and final sperm storage....

  4. Sperm competition in tropical versus temperate zone birds

    Czech Academy of Sciences Publication Activity Database

    Albrecht, Tomáš; Kleven, O.; Kreisinger, J.; Laskemoen, T.; Omotoriogun, T. C.; Ottosson, U.; Reif, J.; Sedláček, O.; Hořák, D.; Robertson, R. J.; Lifjeld, J. T.

    2013-01-01

    Roč. 280, č. 1752 (2013), s. 20122434 ISSN 0962-8452 R&D Projects: GA ČR(CZ) GAP505/11/1617; GA ČR(CZ) GAP506/12/2472 Institutional support: RVO:68081766 Keywords : clutch size * extra-pair paternity * life history * post-copulatory sexual selection * sperm phenotype Subject RIV: EG - Zoology Impact factor: 5.292, year: 2013

  5. Semen Displacement as a Sperm Competition Strategy in Humans

    Directory of Open Access Journals (Sweden)

    Gordon G. Gallup

    2004-01-01

    Full Text Available We examine some of the implications of the possibility that the human penis may have evolved to compete with sperm from other males by displacing rival semen from the cervical end of the vagina prior to ejaculation. The semen displacement hypothesis integrates considerable information about genital morphology and human reproductive behavior, and can be used to generate a number of interesting predictions.

  6. Sperm Competition Risk and Sexual Coercion Predict Copulatory Duration in Humans

    Directory of Open Access Journals (Sweden)

    Nicole Barbaro

    2015-12-01

    Full Text Available A man whose romantic partner is sexually unfaithful is at risk of sperm competition and cuckoldry—unwitting investment in offspring to whom he is genetically unrelated. Men, therefore, may have evolved mechanisms to solve the adaptive problems of sperm competition and cuckoldry. The current research investigates another potential anti-cuckoldry tactic: reducing in-pair copulation (IPC duration, thereby more quickly placing his sperm into competition. We hypothesize that IPC duration will be negatively correlated with female infidelity (Hypothesis 1. We further hypothesize that IPC duration will be negatively correlated with sexual coercion (Hypothesis 2. Results of Study 1 (men’s reports, n = 410 indicate that both men’s perceptions of female infidelity and men’s sexual coercion predict shorter IPC duration. Results of Study 2 (women’s reports, n = 455 did not provide statistical support for the study hypotheses. The current research provides an initial investigation of men’s adjustment of copulatory duration and suggests that men reduce IPC duration and ejaculate more quickly at the couple’s most recent copulation, in response to greater risk of sperm competition and in the context of sexual coercion.

  7. Sperm competition games: A general model for precopulatory male-male competition

    NARCIS (Netherlands)

    Parker, G.A.; Lessells, C.M.; Simmons, L.W.

    2013-01-01

    Reproductive males face a trade-off between expenditure on precopulatory male–male competition—increasing the number of females that they secure as mates—and sperm competition—increasing their fertilization success with those females. Previous sperm allocation models have focused on scramble

  8. Detrimental effects of an autosomal selfish genetic element on sperm competitiveness in house mice.

    Science.gov (United States)

    Sutter, Andreas; Lindholm, Anna K

    2015-07-22

    Female multiple mating (polyandry) is widespread across many animal taxa and indirect genetic benefits are a major evolutionary force favouring polyandry. An incentive for polyandry arises when multiple mating leads to sperm competition that disadvantages sperm from genetically inferior mates. A reduction in genetic quality is associated with costly selfish genetic elements (SGEs), and studies in invertebrates have shown that males bearing sex ratio distorting SGEs are worse sperm competitors than wild-type males.We used a vertebrate model species to test whether females can avoid an autosomal SGE, the t haplotype, through polyandry. The t haplotype inhouse mice exhibits strong drive in t heterozygous males by affecting spermatogenesis and is associated with homozygous in utero lethality. We used controlled matings to test the effect of the t haplotype on sperm competitiveness. Regardless of mating order, t heterozygous males sired only 11% of zygotes when competing against wild-type males, suggesting a very strong effect of the t haplotype on sperm quality. We provide, to our knowledge,the first substantial evidence that polyandry ameliorates the harmful effects of an autosomal SGE arising through genetic incompatibility. We discuss potential mechanisms in our study species and the broader implications for the benefits of polyandry.

  9. Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus.

    Science.gov (United States)

    Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

    2013-09-01

    Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness.

  10. Bigger testes increase paternity in a simultaneous hermaphrodite, independently of the sperm competition level.

    Science.gov (United States)

    Vellnow, N; Marie-Orleach, L; Zadesenets, K S; Schärer, L

    2018-02-01

    Hermaphroditic animals face the fundamental evolutionary optimization problem of allocating their resources to their male vs. female reproductive function (e.g. testes and sperm vs. ovaries and eggs), and this optimal sex allocation can be affected by both pre- and post-copulatory sexual selection. For example, local sperm competition (LSC) - the competition between related sperm for the fertilization of a partner's ova - occurs in small mating groups and can favour a female-biased sex allocation, because, under LSC, investment into sperm production is predicted to show diminishing fitness returns. Here, we test whether higher testis investment increases an individual's paternity success under sperm competition, and whether the strength of this effect diminishes when LSC is stronger, as predicted by sex allocation theory. We created two subsets of individuals of the simultaneously hermaphroditic flatworm Macrostomum lignano - by sampling worms from either the highest or lowest quartile of the testis investment distribution - and estimated their paternity success in group sizes of either three (strong LSC) or eight individuals (weak LSC). Specifically, using transgenic focal individuals expressing a dominant green-fluorescent protein marker, we showed that worms with high testis investment sired 22% more offspring relative to those with low investment, corroborating previous findings in M. lignano and other species. However, the strength of this effect was not significantly modulated by the experienced group size, contrasting theoretical expectations of more strongly diminishing fitness returns under strong LSC. We discuss the possible implications for the evolutionary maintenance of hermaphroditism in M. lignano. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  11. Sperm Precedence in Zebra Finches Does Not Require Special Mechanisms of Sperm Competition

    NARCIS (Netherlands)

    Colegrave, N.; Birkhead, T.R.; Lessells, C.M.

    1995-01-01

    Competition between the spermatozoa of different males to fertilize the eggs of a single female acts as a selection pressure on the behaviour of males and females. However, quantitative predictions about behaviour fan only be made if the paternity consequences of different patterns of copulation are

  12. High level of sperm competition may increase transfer of accessory gland products carried by the love dart of land snails

    NARCIS (Netherlands)

    Lodi, Monica; Staikou, Alexandra; Janssen, Ruben; Koene, Joris M

    2017-01-01

    Postcopulatory adaptations that increase reproductive success compared to rivals, like the transfer of accessory gland products that promote paternity, are common when sperm competition occurs among males. In land snails, the dart shooting behavior and its adaptive significance, in promoting

  13. Sperm competitive ability and genetic relatedness in Drosophila melanogaster: similarity breeds contempt.

    Science.gov (United States)

    Mack, Paul D; Hammock, Brian A; Promislow, Daniel E L

    2002-09-01

    Offspring of close relatives often suffer severe fitness consequences. Previous studies have demonstrated that females, when given a choice, will choose to avoid mating with closely related males. But where opportunities for mate choice are limited or kin recognition is absent, precopulatory mechanisms may not work. In this case, either sex could reduce the risks of inbreeding through mechanisms that occur during or after copulation. During mating, males or females could commit fewer gametes when mating with a close relative. After mating, females could offset the effects of mating with a closely related male through cryptic choice. Few prior studies of sperm competition have examined the effect of genetic similarity, however, and what studies do exist have yielded equivocal results. In an effort to resolve this issue, we measured the outcome of sperm competition when female Drosophila melanogaster were mated to males of four different degrees of genetic relatedness and then to a standardized competitor. We provide the strongest evidence to date that sperm competitive ability is negatively correlated with relatedness, even after controlling for inbreeding depression.

  14. Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative orthogenesis in the absence of sperm competition?

    Directory of Open Access Journals (Sweden)

    van der Horst Gerhard

    2011-12-01

    Full Text Available Abstract Background We have studied sperm structure and motility in a eusocial rodent where reproduction is typically restricted to a single male and behaviourally dominant queen. Males rarely compete for access to the queen during her estrus cycle, suggesting little or no role for sperm competition. Results Our results revealed an atypical mammalian sperm structure with spermatozoa from breeding, subordinate and disperser males being degenerate and almost completely lacking a "mammalian phylogenetic stamp". Sperm structure is characterized by extreme polymorphism with most spermatozoa classified as abnormal. Sperm head shapes include round, oval, elongated, lobed, asymmetrical and amorphous. At the ultrastructural level, the sperm head contains condensed to granular chromatin with large open spaces between the chromatin. Nuclear chromatin seems disorganized since chromatin condensation is irregular and extremely inconsistent. The acrosome forms a cap (ca 35% over the anterior part of the head. A well defined nuclear fossa and neck with five minor sets of banded protein structures are present. The midpiece is poorly organized and contains only 5 to 7 round to oval mitochondria. The flagellar pattern is 9+9+2. A distinct degenerative feature of the tail principal piece is the absence of the fibrous sheath. Only 7% motile spermatozoa were observed which had exceptionally slow swimming speeds. Conclusion In this species, sperm form has simplified and degenerated in many aspects and represents a specialised form of degenerative orthogenesis at the cellular level.

  15. A general description of additive and nonadditive elements of sperm competitiveness and their relation to male fertilization success.

    Science.gov (United States)

    Engqvist, Leif

    2013-05-01

    A complete understanding of male reproductive success, and thus sexual selection, often requires an insight into male success in sperm competition. Genuine conclusions on male sperm competitiveness can only be made in real competitive situations. However, statistical analyses of sperm competitiveness from fertilization success data have been shown to be problematic. Here, I first outline a comprehensive general description of the different additive and nonadditive elements relevant for the outcome of sperm competition staged between two males. Based on this description, I will highlight two main problems that are frequently encountered in experiments aiming at estimating sperm competitiveness. First, I focus on potential problems when using standardized competitors versus random mating trials, because trials with standardized competitors do not allow generalization if male-male interactions are important. Second, I illustrate the necessity to analyze data on the logit scale rather than on raw proportions, because only the logit scale allows a clean separation of additive and nonadditive effects (i.e., male × male and female × male interactions). © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

  16. Mating systems, sperm competition, and the evolution of sexual dimorphism in birds.

    Science.gov (United States)

    Dunn, P O; Whittingham, L A; Pitcher, T E

    2001-01-01

    Comparative analyses suggest that a variety of factors influence the evolution of sexual dimorphism in birds. We analyzed the relative importance of social mating system and sperm competition to sexual differences in plumage and body size (mass and tail and wing length) of more than 1,000 species of birds from throughout the world. In these analyses we controlled for phylogeny and a variety of ecological and life-history variables. We used testis size (corrected for total body mass) as an index of sperm competition in each species, because testis size is correlated with levels of extrapair paternity and is available for a large number of species. In contrast to recent studies, we found strong and consistent effects of social mating system on most forms of dimorphism. Social mating system strongly influenced dimorphism in plumage, body mass, and wing length and had some effect on dimorphism in tail length. Sexual dimorphism was relatively greater in species with polygynous or lekking than monogamous mating systems. This was true when we used both species and phylogenetically independent contrasts for analysis. Relative testis size was also related positively to dimorphism in tail and wing length, but in most analyses it was a poorer predictor of plumage dimorphism than social mating system. There was no association between relative testis size and mass dimorphism. Geographic region and life history were also associated with the four types of dimorphism, although their influence varied between the different types of dimorphism. Although there is much interest in the effects of sperm competition on sexual dimorphism, we suggest that traditional explanations based on social mating systems are better predictors of dimorphism in birds.

  17. A comparison of paternity data and relative testes size as measures of level of sperm competition in the Hominoidea.

    Science.gov (United States)

    Baker, R Robin; Shackelford, Todd K

    2018-03-01

    The phrase "level of sperm competition" is used only vaguely in the primate literature. There is also little distinction between the important elements of frequency and intensity of sperm competition, largely because the two current forms of measurement (socio-sexual system and relative testes size) are both proxies which allow neither precision nor fine distinctions. Both measures have critics, socio-sexual system in particular being branded subjective, misleading, and changeable. Testes size is considered the more reliable despite its validation resting on correlations with the other, less reliable, proxy. Recently, genetic paternity studies have been mooted to provide a potentially superior third measure of sperm competition but so far lack a formal interpretive framework. Here we use the published and relatively comprehensive genetic field studies of the Hominoidea to develop such a framework. Formulae are derived to convert paternity data into a direct measure of the frequency, intensity, and overall level of sperm competition. We then compare these measures with relative testes size at the study, species, and phylogenetic levels. A significant correlation between level of sperm competition and relative testes size was obtained at each level. These correlations provide independent support for the continuing use of testes size as a proxy measure when such a measure is sufficient. However, they also suggest that paternity data and our formulae yield a viable alternative measure. This alternative measure based on paternity data has a number of advantages. Not only is it a potentially direct measure of the level of sperm competition but it also allows the roles of frequency and intensity to be studied separately when of interest. © 2017 Wiley Periodicals, Inc.

  18. Unraveling the Sperm Bauplan: Relationships Between Sperm Head Morphology and Sperm Function in Rodents.

    Science.gov (United States)

    Varea-Sánchez, María; Tourmente, Maximiliano; Bastir, Markus; Roldan, Eduardo R S

    2016-07-01

    Rodents have spermatozoa with features not seen in other species. Sperm heads in many rodent species bear one or more apical extensions known as "hooks." The process by which hooks have evolved, together with their adaptive significance, are still controversial issues. In order to improve our understanding of the biological meaning of these sperm head adaptations, we analyzed hook curvature angles, hook length, and overall hook shape in muroid rodents by using geometric morphometrics. We also searched for relationships between hook design and measurements of intermale competition to assess whether postcopulatory sexual selection was an important selective force driving changes in this sperm structure. Finally, we sought possible links between aspects of sperm hook design and sperm velocity as a measure of sperm performance. Results showed that one hook curvature angle is under strong selective pressure. Similarly, hook length appears to be strongly selected by sexual selection, with this selective force also exhibiting a stabilizing role reducing intermale variation in this trait. The adaptive significance of changes in hook structure was supported by the finding that there are strong and significant covariations between hook dimensions and shape and between hook design and sperm swimming velocity. Overall, this study strongly suggests that postcopulatory sexual selection has an important effect on the design of the sperm head that, in turn, is important for enhancing sperm velocity, a function crucial to reaching the vicinity of the female gamete and winning fertilizations under competitive situations. © 2016 by the Society for the Study of Reproduction, Inc.

  19. Honey increases sperm count in male albino rats by enhancing ...

    African Journals Online (AJOL)

    We investigated the effects of different doses of honey (H) and testosterone (T) on sperm count and reproductive hormones in male albino rats. Thirty-five male albino rats were randomly divided in a blinded fashion into 7 groups of 5 rats each. Group 1 (control) was given 0.2 ml of distilled water. Groups 2, 3 and 4 were ...

  20. Evolution of reduced post-copulatory molecular interactions in Drosophila populations lacking sperm competition.

    Science.gov (United States)

    Hollis, B; Houle, D; Kawecki, T J

    2016-01-01

    In many species with internal fertilization, molecules transferred in the male ejaculate trigger and interact with physiological changes in females. It is controversial to what extent these interactions between the sexes act synergistically to mediate the female switch to a reproductive state or instead reflect sexual antagonism evolved as a by product of sexual selection on males. To address this question, we eliminated sexual selection by enforcing monogamy in populations of Drosophila melanogaster for 65 generations and then measured the expression of male seminal fluid protein genes and genes involved in the female response to mating. In the absence of sperm competition, male and female reproductive interests are perfectly aligned and any antagonism should be reduced by natural selection. Consistent with this idea, males from monogamous populations showed reduced expression of seminal fluid protein genes, 16% less on average than in polygamous males. Further, we identified 428 genes that responded to mating in females. After mating, females with an evolutionary history of monogamy exhibited lower relative expression of genes that were up regulated in response to mating and higher expression of genes that were down-regulated--in other words, their post-mating transcriptome appeared more virgin-like. Surprisingly, these genes showed a similar pattern even before mating, suggesting that monogamous females evolved to be less poised for mating and the accompanying receipt of male seminal fluid proteins. This reduced investment by both monogamous males and females in molecules involved in post-copulatory interactions points to a pervasive role of sexual conflict in shaping these interactions. © 2015 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

  1. Antigen unmasking enhances visualization efficacy of the oocyte activation factor, phospholipase C zeta, in mammalian sperm.

    Science.gov (United States)

    Kashir, Junaid; Buntwal, Luke; Nomikos, Michail; Calver, Brian L; Stamatiadis, Panagiotis; Ashley, Peter; Vassilakopoulou, Vyronia; Sanders, David; Knaggs, Paul; Livaniou, Evangelia; Bunkheila, Adnan; Swann, Karl; Lai, F Anthony

    2017-01-01

    Is it possible to improve clinical visualization of phospholipase C zeta (PLCζ) as a diagnostic marker of sperm oocyte activation capacity and male fertility? Poor PLCζ visualization efficacy using current protocols may be due to steric or conformational occlusion of native PLCζ, hindering antibody access, and is significantly enhanced using antigen unmasking/retrieval (AUM) protocols. Mammalian oocyte activation is mediated via a series of intracellular calcium (Ca 2+ ) oscillations induced by sperm-specific PLCζ. PLCζ represents not only a potential clinical therapeutic in cases of oocyte activation deficiency but also a diagnostic marker of sperm fertility. However, there are significant concerns surrounding PLCζ antibody specificity and detection protocols. Two PLCζ polyclonal antibodies, with confirmed PLCζ specificity, were employed in mouse, porcine and human sperm. Experiments evaluated PLCζ visualization efficacy, and whether AUM improved this. Antibodies against two sperm-specific proteins [post-acrosomal WW-binding protein (PAWP) and acrosin] were used as controls. Aldehyde- and methanol-fixed sperm were subject to immunofluorescence analysis following HCl exposure (pH = 0.1-0.5), acid Tyrode's solution exposure (pH = 2.5) or heating in 10 mM sodium citrate solution (pH = 6.0). Fluorescence intensity of at least 300 cells was recorded for each treatment, with three independent repeats. Despite high specificity for native PLCζ following immunoblotting using epitope-specific polyclonal PLCζ antibodies in mouse, porcine and human sperm, immunofluorescent visualization efficacy was poor. In contrast, sperm markers PAWP and acrosin exhibited relatively impressive results. All methods of AUM on aldehyde-fixed sperm enhanced visualization efficacy for PLCζ compared to visualization efficacy before AUM (P infertility. Our current results suggest that it is perhaps prudent that previous studies investigating links between PLCζ and fertility

  2. Male-biased sex ratio does not promote increased sperm competitiveness in the seed beetle, Callosobruchus maculatus

    Science.gov (United States)

    McNamara, Kathryn B.; Robinson, Stephen P.; Rosa, Márta E.; Sloan, Nadia S.; van Lieshout, Emile; Simmons, Leigh W.

    2016-01-01

    Sperm competition risk and intensity can select for adaptations that increase male fertilisation success. Evolutionary responses are examined typically by generating increased strength of sexual selection via direct manipulation of female mating rates (by enforcing monandry or polyandry) or by alteration of adult sex ratios. Despite being a model species for sexual selection research, the effect of sexual selection intensity via adult sex-ratio manipulation on male investment strategies has not been investigated in the seed beetle, Callosobruchus maculatus. We imposed 32 generations of experimental evolution on 10 populations of beetles by manipulating adult sex ratio. Contrary to predictions, males evolving in male-biased populations did not increase their testes and accessory gland size. This absence of divergence in ejaculate investment was also reflected in the fact that males from male-biased populations were not more successful in either preventing females from remating, or in competing directly for fertilisations. These populations already demonstrate divergence in mating behaviour and immunity, suggesting sufficient generations have passed to allow divergence in physiological and behavioural traits. We propose several explanations for the absence of divergence in sperm competitiveness among our populations and the pitfalls of using sex ratio manipulation to assess evolutionary responses to sexual selection intensity. PMID:27306351

  3. The fate of received sperm in the reproductive tract of a hermaphroditic snail and its implications for fertilisation.

    NARCIS (Netherlands)

    Koene, J.M.; Montagne-Wajer, K; Roelofs, D.; ter Maat, A.

    2009-01-01

    Multiple mating, sperm storage and internal fertilisation enhance sperm competition. The great pond snail can use stored sperm for over three months, and frequently mates with different partners. This hermaphrodite, Lymnaea stagnalis, can also self-fertilise and often produces egg masses containing

  4. Sexual selection and the evolution of sperm quality.

    Science.gov (United States)

    Fitzpatrick, John L; Lüpold, Stefan

    2014-12-01

    Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure that sperm are fertilization-competent and able to overcome the many challenges experienced on their way towards eggs. However, simply being able to fertilize an egg is not enough to ensure male fertility in most species. Owing to the prevalence of female multiple mating throughout the animal kingdom, successful fertilization requires sperm to outcompete rival sperm. In addition, females can actively influence sperm quality, storage or utilization to influence male fertility. This review provides an overview of how these selective forces influence the evolution of sperm quality. After exploring the link between sperm traits and male fertility, we examine how post-mating competition between rival ejaculates influences the evolution of sperm quality. We then describe how complex genetic, social and sexual interactions influence sperm quality, focusing on the importance of seminal fluid and interactions between sperm and the female's reproductive tract. In light of the complexities of selection on sperm traits, greater use of multivariate approaches that incorporate male-male, sperm-sperm and sperm-female interactions to study sperm quality will enhance our understanding of how selection acts on sperm traits and factors influencing male fertility. Because the metric of male reproductive success--fertilization--is the same across the animal kingdom, we argue that information about sperm evolution gained from non-human animals has enormous potential to further our understanding of the factors that impact human fertility. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Competitive intelligence: An instrument to enhance South Africa’s competitiveness

    Directory of Open Access Journals (Sweden)

    Wilma Viviers

    2014-10-01

    Full Text Available The case for Competitive Intelligence (CI as an instrument that can enhance the competitiveness of South African companies and South Africa as a country is strong. Various global competitive rankings measurements have indicated over a number of years the areas in which competitiveness is lacking. Moreover, these rankings have indicated that South Africa has failed to improve its position year on year. The fact that the world is becoming increasingly competitive for South African entities is undisputed. Coupled with a fluctuating exchange rate and the country’s geographical proximity, this poses unique challenges facing South African managers who have to deal with various regulations and legislative matters. In order to create and sustain an effective knowledge economy and to enhance global competitiveness, South Africa however has to put appropriate strategies/measures in place to stimulate, encourage and grow knowledge practices. Competitive Intelligence (CI as a means of making more sense of the competitive business environment and to identify opportunities and risks in time to act upon can be effectively used as a means to enhance competitiveness. Valuable lessons from successful CI practices in the business sector and government can be learnt from elsewhere in the world. CI should be investigated and adapted for South Africa’s business environment. It is therefore the aim of this article to first attempt to describe the role of CI in enhancing competitiveness, specifically in South Africa and secondly, to stimulate thought on how to secure momentum in enhancing CI as an academic field by developing relevant CI courses as well as demonstrating the value of CI to companies in South Africa through research and collaboration between academics and the private and public sectors.

  6. Urban-rural linkages enhancing European territorial competitiveness: background paper

    OpenAIRE

    Davidson, Gill

    2008-01-01

    This background paper provides the context for the seminar on urban-rural linkages enhancing European territorial competitiveness, to be held by DG REGIO on 17th September 2008. This seminar forms part of an ongoing debate at European level on the importance of urban-rural linkages for territorial competitiveness, and on appropriate support mechanisms to assist these developments in Member States.

  7. Enhancing innovation processes through local competitive ...

    African Journals Online (AJOL)

    Mo

    Throughout the world, stakeholders in agriculture are demanding greater participation in the research process. The competitive allocation of public R & D resources to promote institutional pluralism and partnerships in delivering research services currently account for over 12% of all agricultural research funding worldwide.

  8. Increased Expression of the Na,K-ATPase alpha4 Isoform Enhances Sperm Motility in Transgenic Mice1

    Science.gov (United States)

    Jimenez, Tamara; Sanchez, Gladis; McDermott, Jeffrey P.; Nguyen, Anh-Nguyet; Kumar, T. Rajendra; Blanco, Gustavo

    2010-01-01

    The Na,K-ATPase alpha4 (ATP1A4) isoform is specifically expressed in male germ cells and is highly prevalent in spermatozoa. Although selective inhibition of alpha4 activity with ouabain has been shown to affect sperm motility, a more direct analysis of the role of this isoform in sperm movement has not yet been demonstrated. To establish this, we engineered transgenic mice that express the rat alpha4 isoform fused to green fluorescent protein in male germ cells, under the control of the mouse protamine 1 promoter. We showed that the rat Atp1a4 transgene is expressed in mouse spermatozoa and that it is localized to the sperm flagellum. In agreement with increased expression of the alpha4 isoform, sperm from transgenic mice displayed higher alpha4-specific Na,K-ATPase activity and binding of fluorescently labeled ouabain than wild-type mice. In contrast, expression and activity of ATP1A1 (alpha1), the other Na,K-ATPase alpha isoform present in sperm, remained unchanged. Similar to wild-type mice, mice expressing the alpha4 transgene exhibited normal testis and sperm morphology and no differences in fertility. However, compared to wild-type mice, sperm from transgenic mice displayed plasma membrane hyperpolarization and higher total and progressive motility. Other parameters of motility also increased, including straight-line, curvilinear, and average path velocities and amplitude of lateral head displacement. In addition, sperm from the transgenic mice showed enhanced sperm hyperactive motility, but no changes in progesterone-induced acrosome reaction. Altogether, these results provide new genetic evidence for the role of the ATP1A4 isoform in sperm motility, under both noncapacitating and capacitating conditions. PMID:20826726

  9. Enhanced fertility prediction of cryopreserved boar spermatozoa using novel sperm function assessment.

    Science.gov (United States)

    Daigneault, B W; McNamara, K A; Purdy, P H; Krisher, R L; Knox, R V; Rodriguez-Zas, S L; Miller, D J

    2015-05-01

    Due to reduced fertility, cryopreserved semen is seldom used for commercial porcine artificial insemination (AI). Predicting the fertility of individual frozen ejaculates for selection of higher quality semen prior to AI would increase overall success. Our objective was to test novel and traditional laboratory analyses to identify characteristics of cryopreserved spermatozoa that are related to boar fertility. Traditional post-thaw analyses of motility, viability, and acrosome integrity were performed on each ejaculate. In vitro fertilization, cleavage, and blastocyst development were also determined. Finally, spermatozoa-oviduct binding and competitive zona-binding assays were applied to assess sperm adhesion to these two matrices. Fertility of the same ejaculates subjected to laboratory assays was determined for each boar by multi-sire AI and defined as (i) the mean percentage of the litter sired and (ii) the mean number of piglets sired in each litter. Means of each laboratory evaluation were calculated for each boar and those values were applied to multiple linear regression analyses to determine which sperm traits could collectively estimate fertility in the simplest model. The regression model to predict the percent of litter sired by each boar was highly effective (p functions of spermatozoa. © 2015 American Society of Andrology and European Academy of Andrology.

  10. Coevolution of non-fertile sperm and female receptivity in a butterfly.

    Science.gov (United States)

    Wedell, Nina; Wiklund, Christer; Bergström, Jonas

    2009-10-23

    Sexual conflict can promote rapid evolution of male and female reproductive traits. Males of many polyandrous butterflies transfer nutrients at mating that enhances female fecundity, but generates sexual conflict over female remating due to sperm competition. Butterflies produce both normal fertilizing sperm and large numbers of non-fertile sperm. In the green-veined white butterfly, Pieris napi, non-fertile sperm fill the females' sperm storage organ, switching off receptivity and thereby reducing female remating. There is genetic variation in the number of non-fertile sperm stored, which directly relates to the female's refractory period. There is also genetic variation in males' sperm production. Here, we show that females' refractory period and males' sperm production are genetically correlated using quantitative genetic and selection experiments. Thus selection on male manipulation may increase the frequency of susceptible females to such manipulations as a correlated response and vice versa.

  11. Promuovere la competitività europea (Enhancing European competitiveness

    Directory of Open Access Journals (Sweden)

    C.A. CIAMPI

    2013-10-01

    Full Text Available Europe's bid to improve its competitive advantage is hampered by underutilization of its productive potential, as gleaned from its high unemployment rate, and the dissociation of economic growth and employment, where economic development is no longer accompanied by rise in employment. The Competitiveness Advisory Group addresses these issues in its work program and identifies sectors showing the greatest potential for enhancing competitive edge, among which are infrastructure, trade and investment. It also urges the implementation of key policy programs. The Group's proceedings and the main themes of its first two semi-annual reports (June and December 1995 are discussed.JEL: F00

  12. Enhanced fat consumption potentiates acrylamide-induced oxidative stress in epididymis and epididymal sperm and effect spermatogenesis in mice.

    Science.gov (United States)

    Zhang, J X; Yue, W B; Ren, Y S; Zhang, C X

    2010-02-01

    Acrylamide (ACR) and high contents of fat could be found co-existent in many foods processed by high temperature, such as deep-frying and roasting. This study investigated the effect of enhanced fat consumption on deficits of spermatogenesis induced by ACR, and explored potential mechanisms of oxidative damage involved in this pathology in mice. Results show that enhanced feeding of corn oil and pork fat on mice potentiated the decreases of spermatogonia along with mature sperms after treatment of ACR, and that spermatozoa quality is significantly reduced as a result of enhanced feeding of corn oil and pork fat on mice treated with ACR. Moreover, enhanced consumption of corn oil and pork fat potentiated the up-regulation of malondialdehyde (MDA) level in epididymal sperm and cauda epididymides, also up-regulated level of Protein carbonyls (PCOs) in cauda epididymides, of mice after treatment of ACR. Last, enhanced consumption of corn oil and pork fat potentiated the reduced activity of superoxide dismutases (SOD) in epididymal sperm, corpus, and cauda epididymides, also reduced activity of glutathione peroxidase (GPx) in cauda epididymides, of mice treated with ACR. These data suggest that enhanced feeding of corn oil and pork fat on mice potentiates ACR-induced oxidative stress in the epididymis and epididymal sperm and a subsequent effect on spermatogenesis.

  13. Seminal fluid enhances sperm viability in the leafcutter ant Atta colombica

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Boomsma, Jacobus Jan; Baer, Boris

    2008-01-01

    in life, although they may live and produce fertilized eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested...... series, to show that minute quantities of accessory gland secretion achieve significant increases in sperm viability. Sperm stored by queens for 1 year benefited in a similar way from being exposed to accessory gland compounds after dissection in control saline solution. Our results provide the first...

  14. Domestic Wood Products Manufacturing Trends and Factors to Enhance Competitiveness

    Science.gov (United States)

    Urs Buehlmann; Matthew Bumgardner; Albert Schuler; Rich Christianson; Rich Christianson

    2003-01-01

    There is little question that imports have captured a substantial portion of the domestic furniture market. However, there is much speculation and concern as to the future of this and related industries. This study sought to obtain industry perspectives of trends in domestic manufacturing and importing, and to identify factors that can enhance domestic competitiveness...

  15. Strategic Mergers of Strong Institutions to Enhance Competitive Advantage

    Science.gov (United States)

    Harman, Grant; Harman, Kay

    2008-01-01

    Strategic mergers are formal combinations or amalgamations of higher education institutions with the aim of enhancing competitive advantage, or merging for "mutual growth". Recently, in a number of countries, there has been a decided shift from mergers initiated by governments, and dealing mainly with "problem" cases, towards…

  16. THE EVOLUTION OF SPERM SIZE IN BIRDS.

    Science.gov (United States)

    Briskie, James V; Montgomerie, Robert; Birkhead, Tim R

    1997-06-01

    Sperm size varies enormously among species, but the reasons for this variation remain obscure. Since it has been suggested that swimming velocity increases with sperm length, earlier studies proposed longer (and therefore faster) sperm are advantageous under conditions of intense sperm competition. Nonetheless, previous work has been equivocal, perhaps because the intensity of sperm competition was measured indirectly. DNA profiling now provides a more direct measure of the number of offspring sired by extrapair males, and thus a more direct method of assessing the potential for sperm competition. Using a sample of 21 species of passerine birds for which DNA profiling data were available, we found a positive relation between sperm length and the degree of extrapair paternity. A path analysis, however, revealed that this relationship arises only indirectly through the positive relationship between the rate of extrapair paternity and length of sperm storage tubules (SSTs) in the female. As sperm length is correlated positively with SST length, an increase in the intensity of sperm competition leads to an increase in sperm length only through its effect on SST length. Why females vary SST length with the intensity of sperm competition is not clear, but one possibility is that it increases female control over how sperm are used in fertilization. Males, in turn, may respond on an evolutionary time scale to changes in SST size by increasing sperm length to prevent displacement from rival sperm. Previous theoretical analyses predicting that sperm size should decrease as sperm competition becomes more intense were not supported by our findings. We suggest that future models of sperm-size evolution consider not only the role of sperm competition, but also how female control and manipulation of ejaculates after insemination selects for different sperm morphologies. © 1997 The Society for the Study of Evolution.

  17. No evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals.

    Science.gov (United States)

    Tourmente, M; Delbarco Trillo, J; Roldan, E R S

    2015-10-01

    Post-copulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to trade-offs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same energetic budget. Theoretical models have proposed that, in large animals, increased sperm size would have minimal fitness advantage compared with increased sperm numbers. Thus, sperm numbers would evolve more rapidly than sperm size under sperm competition pressure. We tested in mammals whether sperm competition maximizes sperm numbers and size, and whether there is a trade-off between these traits. Our results showed that sperm competition maximizes sperm numbers in eutherian and metatherian mammals. There was no evidence of a trade-off between sperm numbers and sperm size in any of the two mammalian clades as we did not observe any significant relationship between sperm numbers and sperm size once the effect of sperm competition was taken into account. Maximization of both numbers and size in mammals may occur because each trait is crucial at different stages in sperm's life; for example size-determined sperm velocity is a key determinant of fertilization success. In addition, numbers and size may also be influenced by diverse energetic budgets required at different stages of sperm formation. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  18. Unravelling anisogamy: egg size and ejaculate size mediate selection on morphology in free-swimming sperm.

    Science.gov (United States)

    Monro, Keyne; Marshall, Dustin J

    2016-07-13

    Gamete dimorphism (anisogamy) defines the sexes in most multicellular organisms. Theoretical explanations for its maintenance usually emphasize the size-related selection pressures of sperm competition and zygote survival, assuming that fertilization of all eggs precludes selection for phenotypes that enhance fertility. In external fertilizers, however, fertilization is often incomplete due to sperm limitation, and the risk of polyspermy weakens the advantage of high sperm numbers that is predicted to limit sperm size, allowing alternative selection pressures to target free-swimming sperm. We asked whether egg size and ejaculate size mediate selection on the free-swimming sperm of Galeolaria caespitosa, a marine tubeworm with external fertilization, by comparing relationships between sperm morphology and male fertility across manipulations of egg size and sperm density. Our results suggest that selection pressures exerted by these factors may aid the maintenance of anisogamy in external fertilizers by limiting the adaptive value of larger sperm in the absence of competition. In doing so, our study offers a more complete explanation for the stability of anisogamy across the range of sperm environments typical of this mating system and identifies new potential for the sexes to coevolve via mutual selection pressures exerted by gametes at fertilization. © 2016 The Author(s).

  19. Light-emitting diode exposure enhances sperm motility in men with and without asthenospermia: preliminary results

    Directory of Open Access Journals (Sweden)

    Nader Salama

    2015-03-01

    Full Text Available Objective: To evaluate the effect of lightemitting diode (LED on sperm motility in men with and without asthenospermia. Material and Methods: Semen samples from 27 men were assessed and washed. An aliquot was taken from each sample as a control. The remaining amount was exposed to red LED for 2, 5 and 10 minutes. Sperm motility from the test and control tubes were re-checked at the end of each time interval. In 11 of these 27 samples, the same protocol was repeated without sperm washing. Evaluation of sperm creatine kinase (CK activity, hypoosmotic swelling (HOS test and aniline blue staining (ANBS were undertaken after phototherapy in additional 15 samples. Results: Progressive sperm motility increased significantly after LED treatment at the different time intervals whether in washed (p = 0.000 or non-washed (p = 0.003 samples. The amount of the increase in motility in washed aliquots was significantly more (p = 0.000 than in naive semen. Sperm CK activity increased, but was not significant whilst there were no changes regarding HOS and ANBS. Conclusion: Red LED is a promising safe tool to boost sperm motility in vitro. This may have a great implication on maximizing the possibilities and outcomes of intrauterine insemination trials.

  20. Sperm length, sperm storage and mating system characteristics in bumblebees

    DEFF Research Database (Denmark)

    Baer, Boris; Schmid-Hempel, Paul; Høeg, Jens Thorvald

    2003-01-01

    Multiple insemination induces sperm competition and may select for longer, faster moving sperm in species where sperm is short-lived and egg fertilization takes place almost immediately after ejaculation. Here we report the first detailed analysis of sperm length in social insects with long......-term storage of sperm, using three bumblebee species with different mating systems as models. We show that individual males produce only one size-class of sperm, but that sperm length is highly variable among brothers, among unrelated conspecific males, and among males of different species. Males of Bombus...... hypnorum, a species with multiple-mating queens, have longer sperm than males of B. terrestris and B. lucorum whose queens are single mated. Although the sample size on the species level was too small to perform a phylogenetic analysis, this finding supports the hypothesis that, all other things being...

  1. Variation in sperm morphology among Afrotropical sunbirds

    Czech Academy of Sciences Publication Activity Database

    Omotoriogun, T. C.; Laskemoen, T.; Rowe, M.; Albrecht, Tomáš; Bowie, R. C. K.; Sedláček, O.; Hořák, D.; Ottosson, U.; Lifjeld, J. T.

    2016-01-01

    Roč. 158, č. 1 (2016), s. 155-166 ISSN 0019-1019 Institutional support: RVO:68081766 Keywords : comparative analysis * Nectariniidae * phylogenetic signal * sperm competition * sperm size Subject RIV: EG - Zoology Impact factor: 2.279, year: 2016

  2. Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults.

    Science.gov (United States)

    Anderson-Hanley, Cay; Snyder, Amanda L; Nimon, Joseph P; Arciero, Paul J

    2011-01-01

    This study examined the effect of virtual social facilitation and competitiveness on exercise effort in exergaming older adults. Fourteen exergaming older adults participated. Competitiveness was assessed prior to the start of exercise. Participants were trained to ride a "cybercycle;" a virtual reality-enhanced stationary bike with interactive competition. After establishing a cybercycling baseline, competitive avatars were introduced. Pedaling effort (watts) was assessed. Repeated measures ANOVA revealed a significant group (high vs low competitiveness) × time (pre- to post-avatar) interaction (F[1,12] = 13.1, P = 0.003). Virtual social facilitation increased exercise effort among more competitive exercisers. Exercise programs that match competitiveness may maximize exercise effort.

  3. Enhanced fertility prediction of cryopreserved boar spermatozoa using novel sperm function assessment

    Science.gov (United States)

    Cryopreserved semen is seldom used for commercial porcine artificial insemination (AI) despite many advantages that cryopreservation provides. Compared to fresh semen, the fertility of frozen-thawed boar sperm is more variable but usually less. Predicting the fertility of individual ejaculates for s...

  4. A test of the sexy-sperm and good-sperm hypotheses for the evolution of polyandry

    OpenAIRE

    Kathryn B. McNamara; Emile van Lieshout; Leigh W. Simmons

    2014-01-01

    The sexy-sperm hypothesis proposes that polyandrous females will have a selective advantage over monandrous females as their sons will be sired by males with competitively superior sperm and will inherit this trait. Although the good-sperm hypothesis also predicts that offspring will be sired by males with competitively superior sperm, it additionally assumes a positive correlation between offspring sperm quality and the general viability of both sons and daughters. We examined the potential ...

  5. Sperm motility of externally fertilizing fish and amphibians.

    Science.gov (United States)

    Browne, R K; Kaurova, S A; Uteshev, V K; Shishova, N V; McGinnity, D; Figiel, C R; Mansour, N; Agney, D; Wu, M; Gakhova, E N; Dzyuba, B; Cosson, J

    2015-01-01

    We review the phylogeny, sperm competition, morphology, physiology, and fertilization environments of the sperm of externally fertilizing fish and amphibians. Increased sperm competition in both fish and anurans generally increases sperm numbers, sperm length, and energy reserves. The difference between the internal osmolarity and iconicity of sperm cells and those of the aquatic medium control the activation, longevity, and velocity of sperm motility. Hypo-osmolarity of the aquatic medium activates the motility of freshwater fish and amphibian sperm and hyperosmolarity activates the motility of marine fish sperm. The average longevity of the motility of marine fish sperm (~550 seconds) was significantly (P amphibian sperm in general and anurans reversion from internal to external fertilization. Our findings provide a greater understanding of the reproductive biology of externally fertilizing fish and amphibians, and a biological foundation for the further development of reproduction technologies for their sustainable management.

  6. Polyandrous females benefit by producing sons that achieve high reproductive success in a competitive environment

    OpenAIRE

    Firman, Renée C.

    2011-01-01

    Females of many taxa often copulate with multiple males and incite sperm competition. On the premise that males of high genetic quality are more successful in sperm competition, it has been suggested that females may benefit from polyandry by accruing ‘good genes’ for their offspring. Laboratory studies have shown that multiple mating can increase female fitness through enhanced embryo viability, and have exposed how polyandry influences the evolution of the ejaculate. However, such studies o...

  7. Sperm morphology and function in passerine birds: insights from intra- and interspecific studies

    OpenAIRE

    Laskemoen, Terje

    2010-01-01

    Sperm cells are the most variable animal cells, and a tremendous variation in sperm phenotypes exists among species, from minute amoeboid sperm to giant sperm in some species of fruit flies. Much effort has been devoted to the study of sperm evolution. Sperm competition, when sperm from two or more males compete over fertilization of a set of ova, is thought to be the major force driving the evolution of sperm. There are several ways in which sperm competition can effect the evolution of sper...

  8. Enhanced role of elaidic acid on acrylamide-induced oxidative stress in epididymis and epididymal sperm that contributed to the impairment of spermatogenesis in mice.

    Science.gov (United States)

    Zhang, Jian-xin; Yue, W B; Ren, Y S; Zhang, C X

    2010-09-01

    Acrylamide (ACR) and trans fatty acids (TFA) could be found co-existent in many foods processed by high temperature. Our study investigated effect of elaidic acid (ELA), the predominant TFA, on deficits of spermatogenesis induced by ACR. Results showed that ELA enhanced the decreases of spermatogonia along with mature sperms after treatment of ACR, and that spermatozoa quality was significantly reduced by addition of ELA to mice treated with ACR. Moreover, ELA play an enhancing role in ACR-induced up-regulating of malondialdehyde (MDA) level in epididymal sperm and cauda epididymides, also up-regulating of protein carbonyls (PCOs) level in cauda epididymides. Meanwhile, ELA play an enhancing role in ACR-induced reducing of activity of superoxide dismutases (SOD) in epididymal sperm, corpus and cauda epididymides, also the reducing of activity of glutathione peroxidase (GPx) in cauda epididymides. These data suggest that ELA enhances ACR-induced oxidative stress in the epididymis and epididymal sperm of mice and has subsequent effect on spermatogenesis in mice testis.

  9. Key factors enhancing sperm fertilizing ability are transferred from the epididymis to the spermatozoa via epididymosomes in the domestic cat model.

    Science.gov (United States)

    Rowlison, Tricia; Ottinger, Mary Ann; Comizzoli, Pierre

    2017-11-14

    Spermatozoa undergo critical changes in structure and function during the epididymal transit. Our previous studies in the domestic cat demonstrated that incidence of cenexin-a key protein involved in the centrosomal maturation-progressively increases in sperm cells from caput to cauda epididymidis. The objectives of the study were to (1) characterize mechanisms involved in transferring key factors-using the cenexin as a marker-between the epididymis and maturing sperm cells and (2) demonstrate the impact of such mechanisms on the acquisition of functional properties by spermatozoa. Epididymides were dissected from adult cat testes to assess the presence and localization of cenexin in testicular tissues and each epididymal segment (caput, corpus, and cauda) via immunofluorescence, Western blot, and mass spectrometry. Results showed that tissues, luminal fluid, and isolated epididymosomes from each segment contained cenexin. Co-incubation of immature sperm cells for 3 h with luminal fluid or epididymosomes followed by immunostaining revealed that percentages of sperm cells containing cenexin significantly increased in samples co-incubated with epididymosome suspensions. Additionally, epididymosome co-incubation with immature spermatozoa resulted in sustained motility compared to untreated spermatozoa while there was no significant effect on acrosome integrity. Taken together, these results suggest that epididymosomes play a critical role in epididymal sperm maturation and could be ideal vehicles to assist in the enhancement or suppression of male fertility.

  10. Competition

    CERN Document Server

    Staff Association

    2016-01-01

      The Staff Association is organising a competition from 13 to 21 December 2016. There are several Go Sport vouchers to win with a value of 50 € each. Try your luck! To participate, you just have to be a member of the Staff Association and take the online quiz: https://ap-vote.web.cern.ch/content/jeu-concours-de-noel. The winners will be drawn among the correct answers.

  11. Competition

    CERN Document Server

    Staff Association

    2016-01-01

      The Staff Association is organising a competition from April 11 to 20. There are several Go Sport gift vouchers with a value of 50 € each to win. Try your luck! To participate, you just have to be a member of the Staff Association and take the online quiz: https://ap-vote.web.cern.ch/content/jeu-concours. The winners will be drawn among the correct answers.

  12. Competition

    CERN Multimedia

    Staff Association

    2017-01-01

    Get ready for the Easter Egg Hunt! The Staff Association is organising a competition from 10 to 21 April 2017. There are several Go Sport gift vouchers to win, with a value of 50 € each. Try your luck! Count the number of different eggs that we have hidden on our website. Then indicate your answer in the online form. To participate, you just need to be a member of the Staff Association. Winners will be randomly drawn among the correct answers.

  13. Casanovas are liars: behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [v2; ref status: indexed, http://f1000r.es/1ko

    Directory of Open Access Journals (Sweden)

    David Bierbach

    2013-08-01

    Full Text Available Male reproductive biology can by characterized through competition over mates as well as mate choice. Multiple mating and male mate choice copying, especially in internally fertilizing species, set the stage for increased sperm competition, i.e., sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect, thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR. Nevertheless, species might differ consistently in their expression of aggressive and reproductive behaviors, possibly due to varying levels of SCR. In the current study, we present a unique data set comprising ten poeciliid species (in two cases including multiple populations and ask whether species can be characterized through consistent differences in the expression of aggression, sexual activity and changes in mate choice under increased SCR. We found consistent species-specific differences in aggressive behavior, sexual activity as well as in the level of misleading behavior, while decreased preference expression under increased SCR was a general feature of all but one species examined. Furthermore, mean sexual activity correlated positively with the occurrence of potentially misleading behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation, but did not detect a correlation between aggressiveness and

  14. Casanovas are liars: behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [v3; ref status: indexed, http://f1000r.es/1zi

    Directory of Open Access Journals (Sweden)

    David Bierbach

    2013-10-01

    Full Text Available Male reproductive biology can by characterized through competition over mates as well as mate choice. Multiple mating and male mate choice copying, especially in internally fertilizing species, set the stage for increased sperm competition, i.e., sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect, thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR. Nevertheless, species might differ consistently in their expression of aggressive and reproductive behaviors, possibly due to varying levels of SCR. In the current study, we present a unique data set comprising ten poeciliid species (in two cases including multiple populations and ask whether species can be characterized through consistent differences in the expression of aggression, sexual activity and changes in mate choice under increased SCR. We found consistent species-specific differences in aggressive behavior, sexual activity as well as in the level of misleading behavior, while decreased preference expression under increased SCR was a general feature of all but one species examined. Furthermore, mean sexual activity correlated positively with the occurrence of potentially misleading behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation, but did not detect a correlation between aggressiveness and

  15. Enhancing Kenya's Competitiveness in the Knowledge-Based ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Kenya's universities face increasing pressure to play a more active role in national development over and above their traditional teaching and research functions. This project will contribute to Kenya's social and economic development by enhancing the research capacity of public universities through a Research Chairs ...

  16. Use of competitive intelligence in curriculum enhancement through ...

    African Journals Online (AJOL)

    Therefore, academic libraries which play a pivotal role in curriculum enhancement should engage in strategic planning and collection of useful intelligence required to improve institutional operations. Challenges encountered during collection development process in academic libraries were identified. They include ...

  17. The Development of KHI'S Business Model to Enhance Sustainable Competitive Advantage

    OpenAIRE

    Firdaus, Anton; Hamsal, Mohammad

    2013-01-01

    This research about how PT KHI make an improvement in Business model by offering EPC (Engineering, Procurement & Construction) services to costumer to gain a better profit margin. Research result suggests PT KHI to improve its Business Model in order to enhance sustainable competitive advantage. Many competitors have the same business model in industry. PT KHI should offer different business model to stay ahead and winning the competition. The research result indicate based on current con...

  18. Evolution of sperm morphology in anurans: insights into the roles of mating system and spawning location

    OpenAIRE

    Zeng, Yu; Lou, Shang Ling; Liao, Wen Bo; Jehle, Robert

    2014-01-01

    Background: The degree of postcopulatory sexual selection, comprising variable degrees of sperm competition and cryptic female choice, is an important evolutionary\\ud force to influence sperm form and function. Here we investigated the effects of\\ud mating system and spawning location on the evolution of sperm morphology in 67\\ud species of Chinese anurans. We also examined how relative testes mass as an\\ud indicator of the level of sperm competition affected variation in sperm morphology\\ud ...

  19. Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults

    Directory of Open Access Journals (Sweden)

    Anderson-Hanley C

    2011-10-01

    Full Text Available Cay Anderson-Hanley1,2, Amanda L Snyder1, Joseph P Nimon1, Paul J Arciero1,21Healthy Aging and Neuropsychology Lab, Department of Psychology, Union College, Schenectady, NY, USA; 2Health and Exercise Sciences Department, Skidmore College, Saratoga Springs, NY, USAAbstract: This study examined the effect of virtual social facilitation and competitiveness on exercise effort in exergaming older adults. Fourteen exergaming older adults participated. Competitiveness was assessed prior to the start of exercise. Participants were trained to ride a “cybercycle;” a virtual reality-enhanced stationary bike with interactive competition. After establishing a cybercycling baseline, competitive avatars were introduced. Pedaling effort (watts was assessed. Repeated measures ANOVA revealed a significant group (high vs low competitiveness X time (pre- to post-avatar interaction (F[1,12] = 13.1, P = 0.003. Virtual social facilitation increased exercise effort among more competitive exercisers. Exercise programs that match competitiveness may maximize exercise effort.Keywords: exercise, aging, virtual reality, competitiveness, social facilitation, exercise intensity

  20. Evidence for biased use of sperm sources in wild female giant cuttlefish (Sepia apama)

    OpenAIRE

    Naud, Marie-José; Shaw, Paul W; Hanlon, Roger T; Havenhand, Jon N

    2005-01-01

    In species where females store sperm from their mates prior to fertilization, sperm competition is particularly probable. Female Sepia apama are polyandrous and have access to sperm from packages (spermatangia) deposited by males onto their buccal area during mating and to sperm stored in internal sperm-storage organs (receptacles) located below the beak. Here, we describe the structure of the sperm stores in the female's buccal area, use microsatellite DNA analyses to determine the genetic d...

  1. Sperm survival in the female reproductive tract in the fly Scathophaga stercoraria (L.)

    OpenAIRE

    Bernasconi, G.; Hellriegel, B.; Heyland, A.; Ward, P. I.

    2002-01-01

    While sperm competition risk favours males transferring many sperm to secure fertilizations, females of a variety of species actively reduce sperm numbers reaching their reproductive tract, e.g. by extrusion or killing. Potential benefits of spermicide to females include nutritional gains, influence over sperm storage and paternity, and the elimination of sperm bearing somatic mutations that would lower zygote fitness.We investigated changes in sperm viability after in vivo and in vitro expos...

  2. Methyl eugenol aromatherapy enhances the mating competitiveness of male Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae).

    Science.gov (United States)

    Haq, Ihsan; Vreysen, Marc J B; Cacéres, Carlos; Shelly, Todd E; Hendrichs, Jorge

    2014-09-01

    Males of Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae) are strongly attracted to methyl eugenol (ME) (1,2-dimethoxy-4-(2-propenyl)benzene), a natural compound occurring in variety of plant species. ME-feeding is known to enhance male B. carambolae mating competitiveness 3 days after feeding. Enhanced male mating competitiveness due to ME-feeding can increase the effectiveness of sterile insect technique (SIT) manifolds. However, the common methods for emergence and holding fruit flies prior to field releases do not allow the inclusion of any ME feeding treatment after fly emergence. Therefore this study was planned to assess the effects of ME-aromatherapy in comparison with ME feeding on male B. carambolae mating competitiveness as aromatherapy is pragmatic for fruit flies emergence and holding facilities. Effects of ME application by feeding or by aromatherapy for enhanced mating competitiveness were evaluated 3d after treatments in field cages. ME feeding and ME aromatherapy enhanced male mating competitiveness as compared to untreated males. Males treated with ME either by feeding or by aromatherapy showed similar mating success but mating success was significantly higher than that of untreated males. The results are discussed in the context of application of ME by aromatherapy as a pragmatic approach in a mass-rearing facility and its implications for effectiveness of SIT. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. 78 FR 35826 - Unfair Competitive Advantages; Enhancement of the Formal Complaint Process

    Science.gov (United States)

    2013-06-14

    ... relevant legislative history of the Postal Accountability and Enhancement Act (PAEA), Public Law 109-435... competition in the video distribution market by limiting the ability of vertically integrated cable companies... provide AT&T with access to live coverage of San Diego Padres baseball games. See AT&T Services, Inc. v...

  4. Does certificate of need law enhance competition in inpatient care market? An empirical analysis.

    Science.gov (United States)

    Paul, Jomon A; Ni, Huan; Bagchi, Aniruddha

    2017-06-29

    This article investigates the impact of Certificate of Need (CON) laws on competition in the inpatient care market. One of the major criticisms of these laws is that it may hinder competition in the health care market, which can lead to higher prices. However, from a theoretical standpoint, CON laws could also promote competition by limiting excessive expansion from incumbents. Our main conclusion is that CON laws by and large enhanced competition in the inpatient market during the period of our study. This indicates that the effects of CON laws to hinder predatory behavior could dominate its effects of preventing new entrants into the inpatient care market. We do not find statistically significant evidence to reject the exogeneity assumption of either CON laws or their stringency in our study. We also find factors such as proportion of population aged 18-44, proportion of Asian American population, obesity rate, political environment, etc., in a state significantly impact competition. Our findings could shed some light to public policy makers when deciding the appropriate health programs or legislative framework to promote health care market competition and thereby facilitate quality health care.

  5. Moral and social reasons to acknowledge the use of cognitive enhancers in competitive-selective contexts.

    Science.gov (United States)

    Garasic, Mirko D; Lavazza, Andrea

    2016-03-29

    Although some of the most radical hypothesis related to the practical implementations of human enhancement have yet to become even close to reality, the use of cognitive enhancers is a very tangible phenomenon occurring with increasing popularity in university campuses as well as in other contexts. It is now well documented that the use of cognitive enhancers is not only increasingly common in Western countries, but also gradually accepted as a normal procedure by the media as well. In fact, its implementation is not unusual in various professional contexts and it has its peak in colleges (where the trend has been characterized as "academic doping"). Even when certain restrictions in the legislation of a country are indeed in place (i.e. through prescriptions requirements), they are without doubts easy to overcome. The legitimacy and appropriateness of such restrictions will not be the focus of our investigation. Our concern is instead related to the moral and social reasons to publicly acknowledge the use of cognitive enhancers in competitive-selective contexts. These reasons are linked to a more neutral analysis of contemporary Western society: it is a fact that an increasing number of competitive-selective contexts have a substantial number of contenders using cognitive enhancers. Through the use of five explicative examples, in this paper we want to analyse the problems related to its use. In particular, it will be our aim to show the tension between one of the main argument used by bio-liberals (the use of cognitive enhancers is an eligible procedure that society does not impose on anyone) and the actual implementation of the drugs in competitive, or semi-competitive contexts.

  6. Sperm Production Rate, Gonadal and Extragonadal Sperm ...

    African Journals Online (AJOL)

    Five healthy West African Dwarf (WAD) rams, 1.5 to 2.5 years of age and weighing between 15 kg to 20 kg were used to determine daily sperm production, gonadal and exragonadal sperm reserves. Gonadal and extragonadal sperm reserves were estimated by the haemocytometric method, while the daily sperm production ...

  7. Highly sensitive detection of clenbuterol using competitive surface-enhanced Raman scattering immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Guichi [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Hu Yongjun, E-mail: yjhu@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Gao Jiao; Zhong Liang [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China)

    2011-07-04

    Graphical abstract: Schemes of SERS nanoprobes preparation (a) and competitive SERS immunoassay for clenbuterol (b). Highlights: > A new method for clenbuterol detection by the use of a competitive SERS immunoassay has been developed. > 4,4'-Dipyridyl is chosen as the Raman reporter due to its fast-labeled, nontoxic and bifunctional properties. > The present method could detect clenbuterol over a wide dynamic concentration range and exhibit significant specificity in real samples. > The technique is more sensitive and simpler than the conventional method ELISA. - Abstract: In this report, we present a novel approach to detect clenbuterol based on competitive surface-enhanced Raman scattering (SERS) immunoassay. Herein, a SERS nanoprobe that relies on gold nanoparticle (GNP) is labeled by 4,4'-dipyridyl (DP) and clenbuterol antibody, respectively. The detection of clenbuterol is carried out by competitive binding between free clenbuterol and clenbuterol-BSA fastened on the substrate with their antibody labeled on SERS nanoprobes. The present method allows us to detect clenbuterol over a much wider concentration range (0.1-100 pg mL{sup -1}) with a lower limit of detection (ca. 0.1 pg mL{sup -1}) than the conventional methods. Furthermore, by the use of this new competitive SERS immunoassay, the clenbuterol-BSA (antigen) is chosen to fasten on the substrate instead of the clenbuterol antibody, which could reduce the cost of the assay. Results demonstrate that the proposed method has the wide potential applications in food safety and agonist control.

  8. Sperm length evolution in the fungus-growing ants

    DEFF Research Database (Denmark)

    Baer, B.; Dijkstra, M. B.; Mueller, U. G.

    2009-01-01

    Eusocial insects offer special opportunities for the comparative study of sperm traits because sperm competition is absent (in species with obligatory monandry) or constrained (in lineages where queens mate multiply but never remate later in life). We measured sperm length in 19 species of fungus......-growing ants, representing 9 of the 12 recognized genera, and mapped these onto the ant phylogeny. We show that average sperm length across species is highly variable and decreases with mature colony size in basal genera with singly mated queens, suggesting that sperm production or storage constraints affect...... the evolution of sperm length. Sperm length does not decrease further in multiply mating leaf-cutting ants, despite substantial further increases in colony size. In a combined analysis, sexual dimorphism explained 63.1% of the variance in sperm length between species. As colony size was not a significant...

  9. Tenacity of exogenous human papillomavirus DNA in sperm washing.

    Science.gov (United States)

    Brossfield, J E; Chan, P J; Patton, W C; King, A

    1999-07-01

    Sperm cells have been shown to take up exogenous DNA readily. The hypothesis was that sperm washing would remove exogenous viral DNA infecting sperm cells. The objective was to compare three types of sperm washing procedures for their capacity to remove exogenous human papillomavirus (HPV) DNA from infected sperm. Prewashed sperm were equally divided and sperm in one portion were exposed to L1 HPV DNA fragments for 30 min at 37 degrees C. Untreated washed sperm served as the control. After transfection, the sperm were washed by either centrifuge, two-layer Isolate colloid wash, or test-yolk buffer procedures. Sperm parameters were measured on a Hamilton Thorn HTM-C analyzer. Sperm DNA were extracted and polymerase chain reaction (PCR) was carried out targeting the L1 consensus gene of HPV and the designated sentinel gene, 17q21 spanning the D17S855 gene. Amplified products were analyzed in 2% agarose gel electrophoresis. PCR analyses detected the consensus L1 HPV gene in sperm after they were processed through either of the three procedures. Controls were negative for the L1 gene. Extracted DNA were verified by PCR amplification of 17q21 spanning the D17S855 gene. Transfected sperm had higher percentages of total motility and progression compared with the control. Centrifuged, washed, transfected sperm exhibited a greater curvilinear velocity and hyperactivation. The data showed that washing would not remove exogenous HPV DNA from sperm cells. The viral DNA was tenaciously bound to the sperm, suggesting an internalization into the sperm. The viral DNA also increased the motility of the sperm by affecting the velocity and progression of the sperm, which suggested either an increase in metabolism, an enhancement of the calcium-regulated motility mechanism, or an artifact of PCR reagents. More studies are needed to elucidate the mechanism of DNA stimulated sperm motility.

  10. Sperm preparation for fertilization

    NARCIS (Netherlands)

    Gadella, B.M.

    2014-01-01

    Description This book contains 19 chapters that discuss theoretical and applied andrology for domestic, zoo and wild animals. Topics include semen and its constituents; sperm production and harvest; determinants of sperm morphology; sperm preparation for fertilization; practical aspects of semen

  11. Attitudes and motivations of competitive cyclists regarding use of banned and legal performance enhancers.

    Science.gov (United States)

    Kisaalita, Nkaku R; Robinson, Michael E

    2014-01-01

    Drug 'doping' and the use of banned performance enhancing products (PEPs) remains an issue in virtually all competitive sports despite penal consequences and known health risks. The lines distinguishing "fair" and "unfair" performance enhancement have become increasingly blurred. Few studies have explored how attitudes towards legal performance enhancers (drugs/substances, diet, and equipment modifications) may influence motivations to use banned PEPs. In the present study, 68 competitive cyclists completed a survey examining the importance of choosing banned and non-banned PEPs using World Anti-Doping Agency (WADA) and Union Cycliste Internationale (UCI) criteria. Results showed that over 60 percent of cyclists used non-banned PEPs while 8 percent used banned PEPs. Health was overall the most important factor in choosing a PEP while apprehension by a doping agency was least important. Mixed- model ANOVA analyses revealed that motivations to use banned PEPs were complex, as the importance of health, violating the sprit of the sport, performance improvement, and getting caught were differentially influenced by PEP legality (p PEP use (p PEP use (p > 0.05). Our findings illustrate the multifactorial nature of PEP use/doping attitudes and highlight the unique role that "legal" performance enhancement may plays in influencing banned and/or unethical sports behaviors. Key PointsUse of performance enhancers is high even among non-professional athletesCyclists overall rated "risk to health" as the most important factor in choosing to use a performance enhancing product.Motivations to use banned performance enhancer are complex and are significantly influenced by whether an athlete utilizes "legal" performance enhancers.

  12. Optimizing methyl-eugenol aromatherapy to maximize posttreatment effects to enhance mating competitiveness of male Bactrocera carambolae (Diptera: Tephritidae).

    Science.gov (United States)

    Haq, Ihsan ul; Vreysen, Marc J B; Cacéres, Carlos; Shelly, Todd E; Hendrichs, Jorge

    2015-10-01

    Methyl-eugenol (ME) (1,2-dimethoxy-4-(2-propenyl)benzene), a natural phytochemical, did enhance male Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae) mating competitiveness 3 d after ingestion. Enhanced male mating competitiveness can significantly increase the effectiveness of the sterile insect technique (SIT). ME application to mass reared sterile flies by feeding is infeasible. ME application by aromatherapy however, would be a very practical way of ME application in fly emergence and release facilities. This approach was shown to enhance mating competitiveness of B. carambolae 3 d posttreatment (DPT). Despite this added benefit, every additional day of delaying release will reduce sterile fly quality and will add cost to SIT application. The present study was planned to assess the effects of ME-aromatherapy on male B. carambolae mating competitiveness 1DPT and 2DPT. ME aromatherapy 1DPT or 2DPT did enhance mating competitiveness of B. carambolae males whereas ME feeding 1DPT and 2DPT did not. Male mating competitiveness was enhanced by the ME aromatherapy irrespective if they received 1DPT, 2DPT or 3DPT. ME aromatherapy, being a viable approach for its application, did enhance mating competitiveness of male B. carambolae 1 d posttreatment as ME feeding did 3 d after ingestion. ©2014 The Authors Journal compliation © Insititute of Zoology, Chinese Academy of Science.

  13. Attitudes and Motivations of Competitive Cyclists Regarding Use of Banned and Legal Performance Enhancers

    Directory of Open Access Journals (Sweden)

    Nkaku R. Kisaalita

    2014-03-01

    Full Text Available Drug ‘doping’ and the use of banned performance enhancing products (PEPs remains an issue in virtually all competitive sports despite penal consequences and known health risks. The lines distinguishing “fair” and “unfair” performance enhancement have become increasingly blurred. Few studies have explored how attitudes towards legal performance enhancers (drugs/substances, diet, and equipment modifications may influence motivations to use banned PEPs. In the present study, 68 competitive cyclists completed a survey examining the importance of choosing banned and non-banned PEPs using World Anti-Doping Agency (WADA and Union Cycliste Internationale (UCI criteria. Results showed that over 60 percent of cyclists used non-banned PEPs while 8 percent used banned PEPs. Health was overall the most important factor in choosing a PEP while apprehension by a doping agency was least important. Mixed- model ANOVA analyses revealed that motivations to use banned PEPs were complex, as the importance of health, violating the sprit of the sport, performance improvement, and getting caught were differentially influenced by PEP legality (p 0.05. Our findings illustrate the multifactorial nature of PEP use/doping attitudes and highlight the unique role that “legal” performance enhancement may plays in influencing banned and/or unethical sports behaviors.

  14. Sperm velocity and its relation to social status in Arctic charr (Salvelinus alpinus).

    Science.gov (United States)

    Haugland, Thomas; Rudolfsen, Geir; Figenschou, Lars; Folstad, Ivar

    2009-10-01

    Sperm velocity has been shown to be a major determinant of fertilization success of external fertilizers. Yet, sperm velocity varies both within and between ejaculates and only a small number of fast sperm cells within an ejaculate are likely to have the potential of fertilizing the eggs. Having such fast cells should be of special importance during sperm competition, particularly for subordinate males that may release their sperm later or further away from eggs, than dominants. We examined ejaculates of dominant and subordinate male Arctic charr (Salvelinus alpinus), a species with sperm competition. Yet, rather than examining just average sperm velocity values, the aim was to examine whether the fastest fraction of sperm cell from dominant and subordinate males differed in velocity. While there was no difference in the average sperm velocity between dominant and subordinate males, analysis of the fastest swimming sperm cells show that subordinate males have significantly higher initial sperm velocity than dominant males within the 10, 5 and 1% fastest sperm cells. That is, the difference in sperm velocity between dominant and subordinate charr is most predominant among the fastest sperm cells. In sum, this study emphasizes the importance of studying the fastest sperm cells in the ejaculates, as status-dependent differences in sperm velocity may not be detected using average values.

  15. The seminal coagulum favours passage of fast-moving sperm into the uterus in the black-handed spider monkey.

    Science.gov (United States)

    Hernández-López, Leonor; Cerda-Molina, Ana Lilia; Páez-Ponce, Denisse L; Mondragón-Ceballos, Ricardo

    2008-10-01

    In addition to gametes, mammalian internal fertilisation has required the evolution of assorted anatomical, physiological and biochemical devices to deal with intra- and inter-sexual conflict such as sperm competition and female cryptic choice respectively. The seminal coagulum of primates and other mammals is viewed as one of such devices. Among primates, the seminal coagulum characteristically occurs in multi-male and multi-female species, leading us to suppose that it intervenes in sperm competition. However, it can also provide cues to the female reproductive tract about male desired or undesired traits, and therefore deter or favour sperm survival and migration. The present work investigates whether the seminal coagulum of the black-handed spider monkey enhances sperm fertilisation chances by improving the female reproductive tract conditions, and if the female reproductive tract is 'blind' to semen or behaves selectively towards ejaculates of different males. A series of artificial inseminations were done in five females, using the ejaculates of three different males, one at a time, and measuring the presence of distinct types of sperm inside the uteri at 10, 30 and 60 min following the insemination. The presence of coagulum, menstrual phase, and male and female identity only affected fast, straight-moving sperm, with larger amounts of fast sperm appearing inside the uteri when ejaculates had seminal coagulum, as well as when in the periovulatory phase. There was great intra-uterine fast-sperm variation regarding which male's semen inseminated which female. The results provide evidence to account for sexual conflict in the spider monkey as well as a methodological approach to this kind of study.

  16. Competition triggers plasmid-mediated enhancement of substrate utilisation in Pseudomonas putida.

    Directory of Open Access Journals (Sweden)

    Hiren Joshi

    2009-06-01

    Full Text Available Competition between species plays a central role in the activity and structure of communities. Stable co-existence of diverse organisms in communities is thought to be fostered by individual tradeoffs and optimization of competitive strategies along resource gradients. Outside the laboratory, microbes exist as multispecies consortia, continuously interacting with one another and the environment. Survival and proliferation of a particular species is governed by its competitive fitness. Therefore, bacteria must be able to continuously sense their immediate environs for presence of competitors and prevailing conditions. Here we present results of our investigations on a novel competition sensing mechanism in the rhizosphere-inhabiting Pseudomonas putida KT2440, harbouring gfpmut3b-modified Kan(R TOL plasmid. We monitored benzyl alcohol (BA degradation rate, along with GFP expression profiling in mono species and dual species cultures. Interestingly, enhanced plasmid expression (monitored using GFP expression and consequent BA degradation were observed in dual species consortia, irrespective of whether the competitor was a BA degrader (Pseudomonas aeruginosa or a non-degrader (E. coli. Attempts at elucidation of the mechanistic aspects of induction indicated the role of physical interaction, but not of any diffusible compounds emanating from the competitors. This contention is supported by the observation that greater induction took place in presence of increasing number of competitors. Inert microspheres mimicking competitor cell size and concentration did not elicit any significant induction, further suggesting the role of physical cell-cell interaction. Furthermore, it was also established that cell wall compromised competitor had minimal induction capability. We conclude that P. putida harbouring pWW0 experience a competitive stress when grown as dual-species consortium, irrespective of the counterpart being BA degrader or not. The immediate

  17. Postcopulatory sexual selection is associated with accelerated evolution of sperm morphology.

    Science.gov (United States)

    Rowe, Melissah; Albrecht, Tomáš; Cramer, Emily R A; Johnsen, Arild; Laskemoen, Terje; Weir, Jason T; Lifjeld, Jan T

    2015-04-01

    Rapid diversification of sexual traits is frequently attributed to sexual selection, though explicit tests of this hypothesis remain limited. Spermatozoa exhibit remarkable variability in size and shape, and studies report a correlation between sperm morphology (sperm length and shape) and sperm competition risk or female reproductive tract morphology. However, whether postcopulatory processes (e.g., sperm competition and cryptic female choice) influence the speed of evolutionary diversification in sperm form is unknown. Using passerine birds, we quantified evolutionary rates of sperm length divergence among lineages (i.e., species pairs) and determined whether these rates varied with the level of sperm competition (estimated as relative testes mass). We found that relative testes mass was significantly and positively associated with more rapid phenotypic divergence in sperm midpiece and flagellum lengths, as well as total sperm length. In contrast, there was no association between relative testes mass and rates of evolutionary divergence in sperm head size, and models suggested that head length is evolutionarily constrained. Our results are the first to show an association between the strength of sperm competition and the speed of sperm evolution, and suggest that postcopulatory sexual selection promotes rapid evolutionary diversification of sperm morphology. © 2015 The Author(s).

  18. Factors on Enhancing the Competitive Edge and Attributes of Graduates as Inputs to the Development of Teacher Education Enhancement Program

    Directory of Open Access Journals (Sweden)

    Susan S. Janer

    2015-11-01

    Full Text Available In response to the CHED’s Higher Education Development Project and the need to track the status of Sorsogon State College (SSC teacher education graduates, this research was conceptualized. The study aims to gauge the teacher education program’s thrust of providing a quality and relevant education that could ensure worthwhile and appropriate employment opportunity to its graduates. Descriptive research design was employed in this study. Surveys, unstructured interviews, and documentary analysis were undertaken to gather pertinent data among the respondents. The study consists of 427 teacher education graduates who were selected through stratified random technique. This tracer study determined the employability of Teacher Education graduates in SSC, Sorsogon Campus from 2009 to 2013 with an end-view of proposing a Teacher Education Enhancement Program (TEEP to enhance the competitive edge of SSC Teacher Education graduates in all teaching job opportunities. The intellectual, social and linguistic attributes of the SSC graduates were likewise identified in this study. Some of the factors identified by the respondents that could help improve their competitive edge are the pre-service trainings, job placement program, teacher education curriculum enrichment, and Licensure Examination for Teachers (LET review program.

  19. Cytometry of mammalian sperm

    International Nuclear Information System (INIS)

    Gledhill, B.L.

    1983-01-01

    Male germ cells respond dramatically to a variety of insults and are important reproductive dosimeters. Semen analyses are very useful in studies on the effects of drugs, chemicals, and environmental hazards on testicular function, male fertility and heritable germinal mutations. The accessibility of male cells makes them well suited for analytical cytology. We might automate the process of determining sperm morphology but should not do so solely for increased speed. Rather, richer tangible benefits will derive from cytometric evaluation through increased sensitivity, reduced subjectivity, standardization between investigators and laboratories, enhanced archival systems, and the benefits of easily exchanged standardized data. Inroads on the standardization of assays for motility and functional integrity are being made. Flow cytometric analysis of total DNA content of individual sperm is an insensitive means to detect exposure to reproductive toxins because of the small size and low frequency of the DNA content errors. Flow cytometry can be applied to determine the proportions of X- and Y-sperm in semen samples

  20. Cytometry of mammalian sperm

    Energy Technology Data Exchange (ETDEWEB)

    Gledhill, B.L.

    1983-10-11

    Male germ cells respond dramatically to a variety of insults and are important reproductive dosimeters. Semen analyses are very useful in studies on the effects of drugs, chemicals, and environmental hazards on testicular function, male fertility and heritable germinal mutations. The accessibility of male cells makes them well suited for analytical cytology. We might automate the process of determining sperm morphology but should not do so solely for increased speed. Rather, richer tangible benefits will derive from cytometric evaluation through increased sensitivity, reduced subjectivity, standardization between investigators and laboratories, enhanced archival systems, and the benefits of easily exchanged standardized data. Inroads on the standardization of assays for motility and functional integrity are being made. Flow cytometric analysis of total DNA content of individual sperm is an insensitive means to detect exposure to reproductive toxins because of the small size and low frequency of the DNA content errors. Flow cytometry can be applied to determine the proportions of X- and Y-sperm in semen samples.

  1. Highly sensitive detection of clenbuterol using competitive surface-enhanced Raman scattering immunoassay.

    Science.gov (United States)

    Zhu, Guichi; Hu, Yongjun; Gao, Jiao; Zhong, Liang

    2011-07-04

    In this report, we present a novel approach to detect clenbuterol based on competitive surface-enhanced Raman scattering (SERS) immunoassay. Herein, a SERS nanoprobe that relies on gold nanoparticle (GNP) is labeled by 4,4'-dipyridyl (DP) and clenbuterol antibody, respectively. The detection of clenbuterol is carried out by competitive binding between free clenbuterol and clenbuterol-BSA fastened on the substrate with their antibody labeled on SERS nanoprobes. The present method allows us to detect clenbuterol over a much wider concentration range (0.1-100 pg mL(-1)) with a lower limit of detection (ca. 0.1 pg mL(-1)) than the conventional methods. Furthermore, by the use of this new competitive SERS immunoassay, the clenbuterol-BSA (antigen) is chosen to fasten on the substrate instead of the clenbuterol antibody, which could reduce the cost of the assay. Results demonstrate that the proposed method has the wide potential applications in food safety and agonist control. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Left-handed sperm removal by male Calopteryx damselflies (Odonata).

    Science.gov (United States)

    Tsuchiya, Kaori; Hayashi, Fumio

    2014-01-01

    Male genitalia in several insect species are asymmetry in right and left shape. However, the function of such asymmetric male genitalia is still unclear. We found that the male genitalia of the damselfly Calopteryx cornelia (Odonata: Calopterygidae) are morphologically symmetric just after emergence but asymmetric after reproductive maturation. Males remove rival sperm stored in the female bursa copulatrix (single spherical sac) and the following spermatheca (Y-shaped tubular sac) prior to their own ejaculation to prevent sperm competition. Males possess the aedeagus with a recurved head to remove bursal sperm and a pair of spiny lateral processes to remove spermathecal sperm. The right lateral process is less developed than the left, and sperm stored in the right spermathecal tube are rarely removed. Experiments involving surgical cutting of each lateral process demonstrated that only the left process functions in spermathecal sperm removal. Thus, males of C. cornelia are left-handed in their sperm removal behaviour at copulation.

  3. Intraspecific competition between co-infecting parasite strains enhances host survival in African trypanosomes.

    Science.gov (United States)

    Balmer, Oliver; Stearns, Stephen Curtis; Schötzau, Andreas; Brun, Reto

    2009-12-01

    It is becoming increasingly clear that under natural conditions parasitic infections commonly consist of co-infections with multiple conspecific strains. Multiple-strain infections lead to intraspecific interactions and may have important ecological and evolutionary effects on both hosts and parasites. However, experimental evidence on intraspecific competition or facilitation in infections has been scarce because of the technical challenges of distinguishing and tracking individual co-infecting strains. To overcome this limitation, we engineered transgenic strains of the protozoan parasite Trypanosoma brucei, the causal agent of human African sleeping sickness. Different strains were transfected with fluorescence genes of different colors to make them visually distinguishable in order to investigate the effects of multiple-strain infections on parasite population dynamics and host fitness. We infected mice either with each strain alone or with mixes of two strains. Our results show a strong mutual competitive suppression of co-infecting T. brucei strains very early in infection. This mutual suppression changes within-host parasite dynamics and alleviates the effects of infection on the host. The strength of suppression depends on the density of the co-infecting strain, and differences in life-history traits between the strains determine the consequences of strain-strain competition for the host. Unexpectedly, co-infection with a less virulent strain significantly enhances host survival (+15%). Analysis of the strain dynamics reveals that this is due to the suppression of the density of the more virulent strain (-33%), whose degree of impact ultimately determines the physical condition of the host. The competitive suppression is likely caused by allelopathic interference or by apparent competition mediated by strain-specific immune responses. These findings highlight the importance of intraspecific variation for parasite-parasite and parasite-host interactions. To

  4. Accurate sperm morphology assessment predicts sperm function.

    Science.gov (United States)

    Abu Hassan Abu, D; Franken, D R; Hoffman, B; Henkel, R

    2012-05-01

    Sperm morphology has been associated with in vitro as well as in vivo fertilisation. The study aimed to evaluate the possible relation between the percentage of spermatozoa with normal morphology and the following sperm functional assays: (i) zona-induced acrosome reaction (ZIAR); (ii) DNA integrity; (iii) chromatin condensation; (iv) sperm apoptosis; and (v) fertilisation rates. Regression analysis was employed to calculate the association between morphology and different functional tests. Normal sperm morphology correlated significantly with the percentages of live acrosome-reacted spermatozoa in the ZIAR (r = 0.518; P sperm apoptosis (r = -0.395; P = 0.0206; n = 34) and necrosis (r = -0.545; P = 0.0009; n = 34). Negative correlations existed between for the acrosome reaction, and DNA integrity, while negative associations were recorded with the percentages of CMA(3) -positive spermatozoa, apoptotic and necrotic spermatozoa. Sperm morphology is related to sperm dysfunction such as poor chromatin condensation, acrosome reaction and DNA integrity. Negative and significant correlations existed between normal sperm morphology and chromatin condensation, the percentage of spermatozoa with abnormal DNA and spermatozoa with apoptotic activity. The authors do not regard sperm morphology as the only test for the diagnosis of male fertility, but sperm morphology can serve as a valuable indicator of underlying dysfunction. © 2011 Blackwell Verlag GmbH.

  5. Evolution of sperm morphology in anurans: insights into the roles of mating system and spawning location.

    Science.gov (United States)

    Zeng, Yu; Lou, Shang Ling; Liao, Wen Bo; Jehle, Robert

    2014-05-15

    The degree of postcopulatory sexual selection, comprising variable degrees of sperm competition and cryptic female choice, is an important evolutionary force to influence sperm form and function. Here we investigated the effects of mating system and spawning location on the evolution of sperm morphology in 67 species of Chinese anurans. We also examined how relative testes size as an indicator of the level of sperm competition affected variation in sperm morphology across a subset of 29 species. We found a significant association of mating system and spawning location with sperm morphology. However, when removing the effects of body mass or absolute testes mass for species for which such data were available, this effect became non-significant. Consistent with predictions from sperm competition theory, we found a positive correlation between sperm morphology and relative testes size after taking phylogeny into account. Our findings suggest that sexual selection in Chinese anurans favors longer sperm when the level of sperm competition is high. Pre-copulatory male-male competition and spawning location, on the other hand, do not affect the evolution of sperm morphology after taking body mass and absolute testes mass into account.

  6. The Formation of a Positive International Image of Country as a Means of Enhancing Competitiveness

    Directory of Open Access Journals (Sweden)

    Novikova Ludmyla V.

    2017-11-01

    Full Text Available The article is aimed at studying the essence of the concept of «image of the state» and substantiating the conceptual model of forming a positive international image of country as a means of enhancing competitiveness in the international market. The essence of the concept of «image of the State» has been defined. The factors influencing the formation of the international image of country have been distributed and systematized. The principles on which the process of formation of country image of modern format, receiving public recognition and adequate international estimation, have been allocated. A conceptual model of formation of positive international image of country, based on the hypothesis of influence of positive image on creation of significant competitive advantages in the international market of goods and services, has been proposed. The key features of the model are defined as: clear distribution of the roles of the stakeholders of national image – subjects of the global economic system, level of their involvement in the process of formation and integration of the State economy into the system of international institutions.

  7. The Staff Development as a Means of Enhancing the Enterprise Competitiveness

    Directory of Open Access Journals (Sweden)

    Zajtzeva Lyudmila O.

    2017-05-01

    Full Text Available The article is aimed at substantiating the importance of continuous development of staff as a means of enhancing the competitiveness of enterprise. A study on the current experience and issues of dissemination of the standard for HR management at the enterprises in Ukraine and abroad has been provided. The role of HR management in the system of competitive factors has been defined. The staff development strategies that are dependent on analysis of the internal environment and the personnel forecast of enterprise have been outlined. The need to apply both material and moral motivation to employees has been determined. The necessity to match the external conditions and the objectives of enterprise with the methods of labor incentives has been substantiated. Features of employee incentive on the basis of wage have been disclosed. There is a need to assess the quantitative and qualitative results of each employee’s individual work through the additional salaries, including in the form of various fringes, increments, lump sum remunerations, which are of a compensatory nature and allow for a significant individualization.

  8. DECREASING INDIRECT FISCAL PRESSURE – ESSENTIAL TOOL FOR COMPETITIVENESS ENHANCING OF ROMANIA’S TOURISM SECTOR

    Directory of Open Access Journals (Sweden)

    Maria Loredana POPESCU

    2015-07-01

    Full Text Available Present condition of Romanian economy is (still! bad enough, given the yet existent (aftereffects of world economic and financial crisis, so that this economy badly needs bolstering up in any manner whatsoever; considering this perspective, and Romania’s tourism potential, Romania’s tourism sector can become a hub of/for economic recovery. But, in order to do this, Romania’s policymakers need not lose from sight Romania’s long term objectives, whilst trying to attain (just the short term ones. For the latter’ achievement fiscal policy is a main tool, but if this tool is used in extremis tourism sector will definitely suffer. On the other hand, it is also true fiscal policy, if used wisely, is more than able to be an essential tool with which one can enhance competitiveness of Romania’s tourism sector.

  9. Exogenous neurotensin modulates sperm function in Japanese Black cattle.

    Science.gov (United States)

    Umezu, Kohei; Hiradate, Yuuki; Oikawa, Toshinori; Ishiguro, Hirotoshi; Numabe, Takashi; Hara, Kenshiro; Tanemura, Kentaro

    2016-08-25

    Recently, the conception rates after artificial insemination have been pointed out to decline continuously. To overcome this problem, the control of frozen and thawed sperm quality is required. However, the mechanism of bovine sperm functional regulation is still largely unknown. In mammals, the ejaculated sperm are capable of showing fertilizing ability during migration in the female reproductive organs. It is well known that these female organs secrete several factors contributing to sperm capacitation. We previously reported that neurotensin (NT) secreted from the oviduct and cumulus cells enhanced sperm capacitation and acrosome reaction in mice. In this study, we confirmed the expression of the NT receptor (NTR1) in the bovine sperm neck region and the secretion of NT in the bovine uterus and oviduct. The similar expression patterns of NT and NTR1 suggests a conserved mechanism of sperm functional regulation between mouse and cattle. Thus, we examined the effects of exogenous NT on the bovine sperm functions. First, we showed that NT induced sperm protein tyrosine phosphorylation in a dose-dependent manner, suggesting that NT enhances sperm capacitation. Second, we showed that NT induced acrosome reactions of capacitated sperm in a dose-dependent manner, suggesting that NT facilitates acrosome reaction. Finally, we used a computer-aided sperm analysis system to show that NT did not have a great effect on sperm motility. These results suggest that NT acts as a facilitator of sperm capacitation and acrosome reaction in the female reproductive tracts in cattle, highlighting the importance of NT-mediated signaling to regulate sperm functions.

  10. Mating duration and sperm precedence in the spider Linyphia triangularis

    DEFF Research Database (Denmark)

    Weldingh, Ditte L.; Toft, Søren; Larsen, Ole Næsbye

    2011-01-01

    , especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition...... experiments (sterile-male technique) including four treatments, in which the copulation of the first male was interrupted at prescribed phases of the mating sequence, while the second male was allowed a complete mating. Second males spent a shorter time than first males on the behaviours prior to sperm...... transfer, but the amount of sperm (2 droplets) and the time spent in sperm transfer were independent of the females’ mating status. The proportion of females accepting the second male depended on the mating duration of the first male, i.e. whether the first male had transferred one or two sperm droplets...

  11. Enhancing Efficiency of Water Supply – Product Market Competition versus Trade

    OpenAIRE

    Reto Foellmi; Urs Meister

    2004-01-01

    This paper analyses and compares potential efficiency gains induced by the introduction of product market competition and cross boarder trade in the piped water market. We argue that due to the specific circumstances in the water sector product market competition, i.e. competition by common carriage is not expected to be very intensive. The connection of networks could alternatively be used for cross boarder trade between neighboured water utilities. We show that competition by common carriag...

  12. Sperm Surface Proteomics 2

    NARCIS (Netherlands)

    Brewis, I.A.; Gadella, B.M.|info:eu-repo/dai/nl/115389873

    2017-01-01

    This contribution will focus exclusively on the total (global) protein composition (the proteome) of the sperm surface. Immune responses directed towards sperm surface proteins may cause infertility since functionally intact sperm are under immune attack. The immune attack can be achieved directly

  13. Intramale variation in sperm size: functional significance in a polygynous mammal

    Directory of Open Access Journals (Sweden)

    José Luis Ros-Santaella

    2015-12-01

    Full Text Available Studies concerning the relationships between sperm size and velocity at the intraspecific level are quite limited and often yielded contradictory results across the animal kingdom. Intramale variation in sperm size may represent a meaningful factor to predict sperm velocity, due to its relationship with the level of sperm competition among related taxa. Because sperm phenotype is under post-copulatory sexual selection, we hypothesized that a reduced intramale variation in sperm size is associated with sperm competitiveness in red deer. Our results show that low variation in sperm size is strongly related to high sperm velocity and normal sperm morphology, which in turn are good predictors of male fertility in this species. Furthermore, it is well known that the red deer show high variability in testicular mass but there is limited knowledge concerning the significance of this phenomenon at intraspecific level, even though it may reveal interesting processes of sexual selection. Thereby, as a preliminary result, we found that absolute testes mass is negatively associated with intramale variation in sperm size. Our findings suggest that sperm size variation in red deer is under a strong selective force leading to increase sperm function efficiency, and reveal new insights into sexual selection mechanisms.

  14. Amino Sugars Enhance the Competitiveness of Beneficial Commensals with Streptococcus mutans through Multiple Mechanisms.

    Science.gov (United States)

    Zeng, Lin; Farivar, Tanaz; Burne, Robert A

    2016-06-15

    greater capacity to utilize amino sugars than the dental pathogen Streptococcus mutans and that the ability of the model commensal Streptococcus gordonii to compete against S. mutans is substantively enhanced by the presence of amino sugars commonly found in the oral cavity. The mechanisms underlying the greater capacity and competitive enhancements of the commensal are shown to depend on how the genes for the catabolic enzymes are regulated, the role of the allosteric modulators affecting such regulation, and the ability of amino sugars to enhance certain activities of the commensal that are antagonistic to S. mutans. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size.

    Science.gov (United States)

    Gomendio, Montserrat; Tourmente, Maximiliano; Roldan, Eduardo R S

    2011-10-22

    The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the 'metabolic rate constraint hypothesis' which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular

  16. Rogue sperm indicate sexually antagonistic coevolution in nematodes.

    Directory of Open Access Journals (Sweden)

    Ronald E Ellis

    2014-07-01

    Full Text Available Intense reproductive competition often continues long after animals finish mating. In many species, sperm from one male compete with those from others to find and fertilize oocytes. Since this competition occurs inside the female reproductive tract, she often influences the outcome through physical or chemical factors, leading to cryptic female choice. Finally, traits that help males compete with each other are sometimes harmful to females, and female countermeasures may thwart the interests of males, which can lead to an arms race between the sexes known as sexually antagonistic coevolution. New studies from Caenorhabditis nematodes suggest that males compete with each other by producing sperm that migrate aggressively and that these sperm may be more likely to win access to oocytes. However, one byproduct of this competition appears to be an increased probability that these sperm will go astray, invading the ovary, prematurely activating oocytes, and sometimes crossing basement membranes and leaving the gonad altogether. These harmful effects are sometimes observed in crosses between animals of the same species but are most easily detected in interspecies crosses, leading to dramatically lowered fitness, presumably because the competitiveness of the sperm and the associated female countermeasures are not precisely matched. This mismatch is most obvious in crosses involving individuals from androdioecious species (which have both hermaphrodites and males, as predicted by the lower levels of sperm competition these species experience. These results suggest a striking example of sexually antagonistic coevolution and dramatically expand the value of nematodes as a laboratory system for studying postcopulatory interactions.

  17. Daily sperm production

    DEFF Research Database (Denmark)

    Kyjovska, Zdenka Orabi; Boisen, Anne Mette Zenner; Jackson, Petra

    2013-01-01

    instillation with Printex90. Body and testicle weight, sperm content per g testicular parenchyma and daily sperm production (DSP) were assessed. The protocol for assessment of DSP was optimized for application in mice (C57BL/6J) and the influence of different parameters was studied. Maternal particulate...... exposure did not affect DSP statistically significantly in the F1 generation, although TiO2 tended to reduce sperm counts. Overall, time-to-first F2 litter increased with decreasing sperm production. There was no effect on sperm production in the F2 generation originating after TiO2 exposure. F2 offspring......, whose fathers were prenatally exposed to Printex90, showed lowered sperm production. Furthermore, we report statistically significant differences in sperm production between mouse strains....

  18. Enhancing social media competitiveness of small businesses: insights from small pizzerias

    Science.gov (United States)

    He, Wu; Wang, Feng-Kwei; Zha, Shenghua

    2014-07-01

    Social media provide an online platform for enterprises to engage existing customers and attract new customers. Although social media can be easily set up at no cost, however, due to limited human and financial resources, many small businesses find it challenging to compete against large enterprises in social media use. While more and more small businesses have jumped on the bandwagon of social media in recent years, few studies investigated the social media strategies that can help small businesses to survive and even thrive against large competitors in the social media arena. Therefore, we studied 32 small pizzerias in a mid-size U.S. city in terms of their social media use for business. Our study found that small pizzerias emphasizing social media use on community relations and social responsibility tend to be more successful in attracting and engaging local customers. This study also sheds light on both effective strategies and successful practices of social media use by small pizzerias. The insights and recommendations identified from this study can help small businesses to enhance their social media competitiveness against large enterprises.

  19. The Application of Innovative Management Accounting Principles for Enhancing Profitability and Competitiveness: An Exploratory Study of Jamaican Manufacturers

    Directory of Open Access Journals (Sweden)

    Phillip C. James

    2013-07-01

    Full Text Available This study represents the first in management accounting research in Jamaica which seeks to determine the extent to which innovative management accounting principles (IMAPs are applied in the manufacturing sector. The aim is to determine if manufacturers in Jamaica are using IMAPs to improve export competitiveness and enhance profitability .The study also seek to determine the factors that prevent manufacturers from adopting these management accounting principles. Five manufacturing organizations were examined using an exploratory case study approach. Results indicate that companies adopting IMAPs have more reliable information for decision making, higher levels of profitability and competitiveness when compared with non- adopting companies.

  20. Seminal fluid mediates ejaculate competition in social insects

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Boomsma, Jacobus Jan

    2010-01-01

    Queens of ants and bees normally obtain a lifetime supply of sperm on a single day of sexual activity, and sperm competition is expected to occur in lineages where queens receive sperm from multiple males. We compared singly mated (monandrous) and multiply mated (polyandrous) sister groups of ants...... and bees and show that seminal fluid of polyandrous species has a more positive effect on the survival of a male's own sperm than on other males' sperm. This difference was not observed in the monandrous species, suggesting that incapacitation of competing sperm may have independently evolved in both bees...... and ants. In Atta leafcutter ants, the negative effect of the seminal fluid of other males was negated by secretion from the queen sperm-storage organ, suggesting that queens may control ejaculate competition after sperm storage....

  1. Secondary sexual characters and sperm traits in coho salmon Oncorhynchus kisutch.

    Science.gov (United States)

    Pitcher, T E; Doucet, S M; Beausoleil, J-M J; Hanley, D

    2009-05-01

    A study was undertaken to examine secondary sexual characters (spawning colouration and overall body size) in relation to sperm metrics in one alternative reproductive tactic of coho salmon Oncorhynchus kisutch: large hooknose males that spawn in dominance-based hierarchies. Males with less intense red spawning colouration had higher sperm velocities than males with darker red spawning colouration. There was no relationship between male body size and sperm metrics. These results suggest that within an alternative reproductive tactic, variation in sperm competition intensity may select for a trade-off between investment in sexual colouration and sperm quality.

  2. Sperm preparation for fertilization

    OpenAIRE

    Gadella, B.M.

    2014-01-01

    Description This book contains 19 chapters that discuss theoretical and applied andrology for domestic, zoo and wild animals. Topics include semen and its constituents; sperm production and harvest; determinants of sperm morphology; sperm preparation for fertilization; practical aspects of semen cryopreservation; evaluation of semen in the andrology laboratory; genetic aspects of male reproduction; emerging techniques and future development of semen evaluation and handling and applied androlo...

  3. Random sperm use and genetic effects on worker caste fate in Atta colombica leaf-cutting ants

    DEFF Research Database (Denmark)

    Holman, Luke; Stürup, Marlene; Trontti, Kalevi

    2011-01-01

    molecular tools to uncover some of the mechanisms and consequences of sperm competition in the leaf-cutting ant Atta colombica, a species with extreme worker size polymorphism. Competitive PCR allowed quantification of the relative numbers of sperm stored by queens from different males, and offspring...... genotyping revealed how sperm number translated into paternity of eggs and adult workers. We demonstrate that fertilization success is directly related to sperm numbers, that stored sperm are well-mixed and that egg paternity is constant over time. Moreover, worker size was found to have a considerable...

  4. Advanced sperm selection techniques for assisted reproduction.

    Science.gov (United States)

    McDowell, Simon; Kroon, Ben; Ford, Emily; Hook, Ysanne; Glujovsky, Demián; Yazdani, Anusch

    2014-10-28

    Assisted reproductive technologies (ART) such as in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) bring together gametes outside of the body to enhance the probability of fertilisation and pregnancy. Advanced sperm selection techniques are increasingly being employed in ART, most commonly in cycles utilising ICSI. Advanced sperm selection techniques are thought to improve the chance that structurally intact and mature sperm with high DNA integrity are selected for fertilisation. Advanced sperm selection strategies include selection according to surface charge; sperm apoptosis; sperm birefringence; ability to bind to hyaluronic acid; and sperm morphology under ultra-high magnification. These techniques theoretically improve ART outcomes. To evaluate the impact of advanced sperm selection techniques on ART outcomes. Systematic search of electronic databases (Cochrane Menstrual Disorders and Subfertility Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Latin American and Caribbean Health Science Information Database (LILACS)), trials registers (ClinicalTrials.gov, Current Controlled Trials, World Health Organization International Clinical Trials Registry Platform), conference abstracts (Web of Knowledge) and grey literature (OpenGrey) for relevant randomised controlled trials. We handsearched the reference lists of included studies and similar reviews. The search was conducted in May 2014. We included randomised controlled trials (RCTs) comparing an advanced sperm selection technique versus standard IVF or ICSI or versus another advanced sperm selection technique. We excluded studies of sperm selection using ultra-high magnification (intracytoplasmic morphologically selected sperm injection, or IMSI), as they are the subject of a separate Cochrane review. Quasi-randomised and pseudo-randomised trials were

  5. Evidence for biased use of sperm sources in wild female giant cuttlefish (Sepia apama).

    Science.gov (United States)

    Naud, Marie-José; Shaw, Paul W; Hanlon, Roger T; Havenhand, Jon N

    2005-05-22

    In species where females store sperm from their mates prior to fertilization, sperm competition is particularly probable. Female Sepia apama are polyandrous and have access to sperm from packages (spermatangia) deposited by males onto their buccal area during mating and to sperm stored in internal sperm-storage organs (receptacles) located below the beak. Here, we describe the structure of the sperm stores in the female's buccal area, use microsatellite DNA analyses to determine the genetic diversity of stored sperm and combine these data with offspring genotypes to determine the storage location of paternal sperm. The number of male genotypes represented in the sperm receptacles was significantly lower than that found among the spermatangia. Estimation of the volumes of sperm contained in the receptacles and the spermatangia were statistically comparable; however, paternal sperm were more likely to have come from spermatangia than from the sperm receptacles. These results confirm a genetic polyandrous mating system in this species and suggest that fertilization pattern with respect to the sperm stores used is not random.

  6. Rheotaxis guides mammalian sperm

    Science.gov (United States)

    Miki, Kiyoshi; Clapham, David E

    2013-01-01

    Background In sea urchins, spermatozoan motility is altered by chemotactic peptides, giving rise to the assumption that mammalian eggs also emit chemotactic agents that guide spermatozoa through the female reproductive tract to the mature oocyte. Mammalian spermatozoa indeed undergo complex adaptations within the female (the process of capacitation) that are initiated by agents ranging from pH to progesterone, but these factors are not necessarily taxic. Currently, chemotaxis, thermotaxis, and rheotaxis have not been definitively established in mammals. Results Here, we show that positive rheotaxis, the ability of organisms to orient and swim against the flow of surrounding fluid, is a major taxic factor for mouse and human sperm. This flow is generated within 4 hours of sexual stimulation and coitus in female mice; prolactin-triggered oviductal fluid secretion clears the oviduct of debris, lowers viscosity, and generates the stream that guides sperm migration in the oviduct. Rheotaxic movement is demonstrated in capacitated and uncapacitated spermatozoa in low and high viscosity medium. Finally, we show that a unique sperm motion we quantify using the sperm head's rolling rate reflects sperm rotation that generates essential force for positioning the sperm in the stream. Rotation requires CatSper channels, presumably by enabling Ca2+ influx. Conclusions We propose that rheotaxis is a major determinant of sperm guidance over long distances in the mammalian female reproductive tract. Coitus induces fluid flow to guide sperm in the oviduct. Sperm rheotaxis requires rotational motion during CatSper channel-dependent hyperactivated motility. PMID:23453951

  7. Prostaglandin E2 enhances long-term repopulation but does not permanently alter inherent stem cell competitiveness.

    Science.gov (United States)

    Hoggatt, Jonathan; Mohammad, Khalid S; Singh, Pratibha; Pelus, Louis M

    2013-10-24

    Hematopoietic stem cell (HSC) transplantation is a lifesaving therapy for malignant and nonmalignant hematologic diseases and metabolic disorders. Although successful, hematopoietic transplantation can be hindered by inadequate stem cell number or poor engrafting efficiency. To overcome these deficits, we and others have previously reported the HSC-enhancing ability of a short-term exposure of prostaglandin E2 (PGE2); this strategy has now progressed to phase 1 clinical trials in double cord blood transplantation. To further analyze the short- and long-term effects of HSC exposure to PGE2, we followed the repopulation kinetics of PGE2-treated hematopoietic grafts through 5 serial transplantations and compared inherent long-term competitiveness in a HSC head-to-head secondary transplantation model. Treatment with PGE2 did not result in a long-term increase in HSC competitiveness, lineage bias, or enhanced proliferative potential, demonstrating that pulse exposure to PGE2 results in transient increases in HSC homing and engraftment potential.

  8. Social facilitation in virtual reality-enhanced exercise: competitiveness moderates exercise effort of older adults

    OpenAIRE

    Anderson-Hanley, Cay; Snyder, Amanda L; Nimon, Joseph P; Arciero, Paul J

    2011-01-01

    Cay Anderson-Hanley1,2, Amanda L Snyder1, Joseph P Nimon1, Paul J Arciero1,21Healthy Aging and Neuropsychology Lab, Department of Psychology, Union College, Schenectady, NY, USA; 2Health and Exercise Sciences Department, Skidmore College, Saratoga Springs, NY, USAAbstract: This study examined the effect of virtual social facilitation and competitiveness on exercise effort in exergaming older adults. Fourteen exergaming older adults participated. Competitiveness was assessed prior to the start...

  9. Enhancing competitiveness of small and medium enterprises and entrepreneurs through forming of clusters

    Directory of Open Access Journals (Sweden)

    Mitrović Vladimir

    2014-01-01

    Full Text Available Clusters, as a form of self-organization of enterprises and associated institutions, help increase levels of competitiveness of its members by inspiring competition and cooperation. The question of increasing the popularity of clusters is especially important at the present moment when creators of economical politics are focused on finding the leading multinational companies, who's involvement on Serbia's market and starting of production, with a possibility to export it, would create opportunities to take over some of their suppliers by Serbia's SMEs. The analysis of selected European clusters has shown that joining of SMEs into clusters increases their productivity, competitiveness and export capability. Dynamic development of SMEs in Serbia will not be possible without intensified efforts in overcoming the main limitations and impediments, perhaps most importantly insufficient competitiveness and quality of products, poor organization on territorial and branch levels and prolonged amounting of unpaid bills. That is why the government has a defining role to play in creating a healthy competitive ambient, because of all the factors involved on the market, often non-economical factors, as well, and often many elements and institutions, and if the government does not take proper measures it'll create a bad business ambient in which SMEs can't use their full potential.

  10. Sperm storage potential and daily sperm production of brown male ...

    African Journals Online (AJOL)

    Sperm storage potential and daily sperm production of brown male Japanese quails for three different physiological age groups. ... positively correlated (r=0.91 P<0.01). This study revealed that the brown male Japanese quail has its peak reproduction potential at puberty. Keywords: Quail sperm storage, sperm production ...

  11. Maintenance of sperm variation in a highly promiscuous wild bird.

    Science.gov (United States)

    Calhim, Sara; Double, Michael C; Margraf, Nicolas; Birkhead, Tim R; Cockburn, Andrew

    2011-01-01

    Postcopulatory sexual selection is an important force in the evolution of reproductive traits, including sperm morphology. In birds, sperm morphology is known to be highly heritable and largely condition-independent. Theory predicts, and recent comparative work corroborates, that strong selection in such traits reduces intraspecific phenotypic variation. Here we show that some variation can be maintained despite extreme promiscuity, as a result of opposing, copulation-role-specific selection forces. After controlling for known correlates of siring success in the superb fairy-wren (Malurus cyaneus), we found that (a) lifetime extra-pair paternity success was associated with sperm with a shorter flagellum and relatively large head, and (b) males whose sperm had a longer flagellum and a relatively smaller head achieved higher within-pair paternity. In this species extrapair copulations occur in the same morning, but preceding, pair copulations during a female's fertile period, suggesting that shorter and relatively larger-headed sperm are most successful in securing storage (defense), whereas the opposite phenotype might be better at outcompeting stored sperm (offense). Furthermore, since cuckolding ability is a major contributor to differential male reproductive output, stronger selection on defense sperm competition traits might explain the short sperm of malurids relative to other promiscuous passerines.

  12. Maintenance of sperm variation in a highly promiscuous wild bird.

    Directory of Open Access Journals (Sweden)

    Sara Calhim

    Full Text Available Postcopulatory sexual selection is an important force in the evolution of reproductive traits, including sperm morphology. In birds, sperm morphology is known to be highly heritable and largely condition-independent. Theory predicts, and recent comparative work corroborates, that strong selection in such traits reduces intraspecific phenotypic variation. Here we show that some variation can be maintained despite extreme promiscuity, as a result of opposing, copulation-role-specific selection forces. After controlling for known correlates of siring success in the superb fairy-wren (Malurus cyaneus, we found that (a lifetime extra-pair paternity success was associated with sperm with a shorter flagellum and relatively large head, and (b males whose sperm had a longer flagellum and a relatively smaller head achieved higher within-pair paternity. In this species extrapair copulations occur in the same morning, but preceding, pair copulations during a female's fertile period, suggesting that shorter and relatively larger-headed sperm are most successful in securing storage (defense, whereas the opposite phenotype might be better at outcompeting stored sperm (offense. Furthermore, since cuckolding ability is a major contributor to differential male reproductive output, stronger selection on defense sperm competition traits might explain the short sperm of malurids relative to other promiscuous passerines.

  13. No evidence for pre-copulatory sexual selection on sperm length in a passerine bird.

    Science.gov (United States)

    Lifjeld, Jan T; Laskemoen, Terje; Kleven, Oddmund; Pedersen, A Tiril M; Lampe, Helene M; Rudolfsen, Geir; Schmoll, Tim; Slagsvold, Tore

    2012-01-01

    There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection.

  14. No evidence for pre-copulatory sexual selection on sperm length in a passerine bird.

    Directory of Open Access Journals (Sweden)

    Jan T Lifjeld

    Full Text Available There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection.

  15. Morphometry of boar sperm head and flagellum in semen backflow after insemination.

    Science.gov (United States)

    García-Vázquez, Francisco Alberto; Hernández-Caravaca, Iván; Yánez-Quintana, Wellington; Matás, Carmen; Soriano-Úbeda, Cristina; Izquierdo-Rico, María José

    2015-09-01

    Once deposited in the female reproductive system, sperm begin their competition and undergo a selection to reach the site of fertilization. Little is known about the special characteristics of sperm that reach the oviduct and are able to fertilize, with even less information on the role of sperm dimension and shape in transport and fertilization. Here, we examine whether sperm morphometry could be involved in their journey within the uterus. For this purpose, sperm head dimension (length, width, area, and perimeter) and shape (shape factor, ellipticity, elongation, and regularity), and flagellum length were analyzed in the backflow at different times after insemination (0-15, 16-30, and 31-60 minutes). Sperm morphometry in the backflow was also analyzed taking into account the site of semen deposition (cervical vs. intrauterine). Finally, flagellum length was measured at the uterotubal junction. Sperm analyzed in the backflow were small (head and flagellum) with different head shapes compared with sperm observed in the dose before insemination. The site of deposition influenced head morphometry and tail size both being smaller in the backflow after cervical insemination compared with intrauterine insemination. Mean tail length of sperm collected in the backflow was smaller than that in the insemination dose and at the uterotubal junction. Overall, our results suggest that sperm size may be involved in sperm transport either because of environment or through sperm selection and competence on their way to encounter the female gamete. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. No Evidence for Pre-Copulatory Sexual Selection on Sperm Length in a Passerine Bird

    Science.gov (United States)

    Lifjeld, Jan T.; Laskemoen, Terje; Kleven, Oddmund; Pedersen, A. Tiril M.; Lampe, Helene M.; Rudolfsen, Geir; Schmoll, Tim; Slagsvold, Tore

    2012-01-01

    There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection. PMID:22384277

  17. Exploring Market and Competitive Intelligence Research as a Source for Enhancing Innovation Capacity

    Science.gov (United States)

    Bajaj, Deepak

    2015-01-01

    The purpose of this study was to assess the role of Competitive and Market Intelligence (CI/MI) Research as a potential source for improving the innovation capability of Small and Medium Enterprises (SME's) leading to successful new product/services/processes/capabilities development (Cooper & Edgett, 2002). This report highlights the…

  18. The application of quality management (TQM to enhance the competitiveness of agricultural entities

    Directory of Open Access Journals (Sweden)

    Jelena Kristić

    2016-12-01

    Full Text Available In recent years quality management has become a new management segment and the most important factor in the market survival as well as in the growth and the development of business entities in most European and other countries worldwide. In order to determine characteristics of an efficient quality management system in agricultural entities and their impact on financial, economic and business performance and competitiveness, primary research was carried out on a sample of 248 respondents, i.e. the representatives of Croatian agricultural entities. The results of the research indicate there is a statistically significant relationship between a high level of TQM application and the horizontal and flexible organization structure, defined mission and vision, systematic observation of changes in the market, stable top management support, employee empowerment and their involvement in quality management activities, creating business environment that supports employee initiatives, education and training, measurable quality objectives, clear understanding of quality concept, business process evaluation and improvement, by using a proactive approach, and finally, orientation towards consumers. The study has found that TQM improves the financial, economic and business performance, i.e. increases market share, price competitiveness, competitive advantage, total sales, the introduction of new products, profitability, input use efficiency, exports, as well as employee and consumer satisfaction. Cost reduction is another advantage. Understanding the role of TQM is essential for gaining competitive advantage, which agricultural entities can achieve only through the synergy of all these elements.

  19. Framework for Educational Robotics: A Multiphase Approach to Enhance User Learning in a Competitive Arena

    Science.gov (United States)

    Lye, Ngit Chan; Wong, Kok Wai; Chiou, Andrew

    2013-01-01

    Educational robotics involves using robots as an educational tool to provide a long term, and progressive learning activity, to cater to different age group. The current concern is that, using robots in education should not be an instance of a one-off project for the sole purpose of participating in a competitive event. Instead, it should be a…

  20. Enhancing Undergraduates' Capabilities through Team-Based Competitions: The Edward Jones Challenge

    Science.gov (United States)

    Umble, Elisabeth J.; Umble, Michael; Artz, Kendall

    2008-01-01

    The Edward Jones Company recently initiated financial sponsorship of team-based competitions in six undergraduate business core classes at Baylor University. The challenges were chosen to take place in an introductory freshman business class, Managerial Accounting, Principles of Marketing, Corporate Finance, Operations Management, and Strategic…

  1. High CO2 enhances the competitive strength of seaweeds over corals

    Science.gov (United States)

    Diaz-Pulido, Guillermo; Gouezo, Marine; Tilbrook, Bronte; Dove, Sophie; Anthony, Kenneth R N

    2011-01-01

    Space competition between corals and seaweeds is an important ecological process underlying coral-reef dynamics. Processes promoting seaweed growth and survival, such as herbivore overfishing and eutrophication, can lead to local reef degradation. Here, we present the case that increasing concentrations of atmospheric CO2 may be an additional process driving a shift from corals to seaweeds on reefs. Coral (Acropora intermedia) mortality in contact with a common coral-reef seaweed (Lobophora papenfussii) increased two- to threefold between background CO2 (400 ppm) and highest level projected for late 21st century (1140 ppm). The strong interaction between CO2 and seaweeds on coral mortality was most likely attributable to a chemical competitive mechanism, as control corals with algal mimics showed no mortality. Our results suggest that coral (Acropora) reefs may become increasingly susceptible to seaweed proliferation under ocean acidification, and processes regulating algal abundance (e.g. herbivory) will play an increasingly important role in maintaining coral abundance. PMID:21155961

  2. Sperm quality after swim up and density gradient centrifugation sperm preparation with supplementation of alpha lipoic acid (ALA): A preliminary study

    Science.gov (United States)

    Lestari, Silvia W.; Lestari, Sarah H.; Pujianto, Dwi A.

    2018-02-01

    Intra uterine insemination (IUI) as one of the treatment for infertility, persists low success rate. A factor that contributes to the unsuccessful of IUI is sperm preparation, performed through Swim-up (SU) and Density Gradient Centrifugation (DGC) methods. Furthermore, studies have shown that Alpha Lipoic Acid (ALA) is a potent antioxidant that could enhance the sperm motility and protect the DNA integrity of the sperm [1]. This study is aimed to re-evaluate the efficiency of the DGC and SU methods in selecting sperm before being transferred for IUI by the supplementation of ALA based on the sperm DNA integrity. Semen samples were obtained from 13 men from partners of women who are infertile (normozoospermia) and underwent IUI. Semen analysis based on the guideline of World Health Organization (WHO) 2010 was performed to measure the sperm motility and velocity, before and after sperm preparation. Then, samples were incubated with Alpha Lipoic Acid (ALA) in 0.625 mg (ALA 1), 1.25 mg (ALA 2) and 2.5 mg (ALA 3). The Sperm Chromatin Dispersion (SCD) test was performed to evaluate the sperm DNA Fragmentation Index (DFI). The percentage of motile sperm was higher in prepared sperm (post-DGC and post-SU) than in whole semen. Furthermore, the percentage of motile sperm was higher in post-DGC compared to post-SU. The level of DFI after the supplementation of ALA was decreased in prepared sperm compared to the whole semen. ALA was proved capable to select the better sperm quality with decreased sperm DNA fragmentation of prepared sperm in the all of DFI category.

  3. Drought enhances symbiotic dinitrogen fixation and competitive ability of a temperate forest tree.

    Science.gov (United States)

    Wurzburger, Nina; Miniat, Chelcy Ford

    2014-04-01

    General circulation models project more intense and frequent droughts over the next century, but many questions remain about how terrestrial ecosystems will respond. Of particular importance, is to understand how drought will alter the species composition of regenerating temperate forests wherein symbiotic dinitrogen (N2)-fixing plants play a critical role. In experimental mesocosms we manipulated soil moisture to study the effect of drought on the physiology, growth and competitive interactions of four co-occurring North American tree species, one of which (Robinia pseudoacacia) is a symbiotic N2-fixer. We hypothesized that drought would reduce growth by decreasing stomatal conductance, hydraulic conductance and increasing the water use efficiency of species with larger diameter xylem vessel elements (Quercus rubra, R. pseudoacacia) relative to those with smaller elements (Acer rubrum and Liriodendron tulipifera). We further hypothesized that N2 fixation by R. pseudoacacia would decline with drought, reducing its competitive ability. Under drought, growth declined across all species; but, growth and physiological responses did not correspond to species' hydraulic architecture. Drought triggered an 80% increase in nodule biomass and N accrual for R. pseudoacacia, improving its growth relative to other species. These results suggest that drought intensified soil N deficiency and that R. pseudoacacia's ability to fix N2 facilitated competition with non-fixing species when both water and N were limiting. Under scenarios of moderate drought, N2 fixation may alleviate the N constraints resulting from low soil moisture and improve competitive ability of N2-fixing species, and as a result, supply more new N to the ecosystem.

  4. In-planta Sporulation Capacity Enhances Infectivity and Rhizospheric Competitiveness of Frankia Strains.

    Science.gov (United States)

    Cotin-Galvan, Laetitia; Pozzi, Adrien C; Schwob, Guillaume; Fournier, Pascale; Fernandez, Maria P; Herrera-Belaroussi, Aude

    2016-01-01

    Frankia Sp+ strains maintain their ability to sporulate in symbiosis with actinorhizal plants, producing abundant sporangia inside host plant cells, in contrast to Sp- strains, which are unable to perform in-planta sporulation. We herein examined the role of in-planta sporulation in Frankia infectivity and competitiveness for root infection. Fifteen strains belonging to different Sp+ and Sp- phylogenetic lineages were inoculated on seedlings of Alnus glutinosa (Ag) and A. incana (Ai). Strain competitiveness was investigated by performing Sp-/Sp+ co-inoculations. Plant inoculations were standardized using crushed nodules obtained under laboratory-controlled conditions (same plant species, age, and environmental factors). Specific oligonucleotide primers were developed to identify Frankia Sp+ and/or Sp- strains in the resulting nodules. Single inoculation experiments showed that (i) infectivity by Sp+ strains was significantly greater than that by Sp- strains, (ii) genetically divergent Sp+ strains exhibited different infective abilities, and (iii) Sp+ and Sp- strains showed different host preferences according to the origin (host species) of the inocula. Co-inoculations of Sp+ and Sp- strains revealed the greater competitiveness of Sp+ strains (98.3 to 100% of Sp+ nodules, with up to 15.6% nodules containing both Sp+ and Sp- strains). The results of the present study highlight differences in Sp+/Sp- strain ecological behaviors and provide new insights to strengthen the obligate symbiont hypothesis for Sp+ strains.

  5. Breeding cereal crops for enhanced weed suppression: optimizing allelopathy and competitive ability.

    Science.gov (United States)

    Worthington, Margaret; Reberg-Horton, Chris

    2013-02-01

    Interest in breeding grain crops with improved weed suppressive ability is growing in response to the evolution and rapid expansion of herbicide resistant populations in major weeds of economic importance, environmental concerns, and the unmet needs of organic producers and smallholder farmers without access to herbicides. This review is focused on plant breeding for weed suppression; specifically, field and laboratory screening protocols, genetic studies, and breeding efforts that have been undertaken to improve allelopathy and competition in rice, wheat, and barley. The combined effects of allelopathy and competition determine the weed suppressive potential of a given cultivar, and research groups worldwide have been working to improve both traits simultaneously to achieve maximum gains in weed suppression. Both allelopathy and competitive ability are complex, quantitatively inherited traits that are heavily influenced by environmental factors. Thus, good experimental design and sound breeding procedures are essential to achieve genetic gains. Weed suppressive rice cultivars are now commercially available in the U.S. and China that have resulted from three decades of research. Furthermore, a strong foundation has been laid during the past 10 years for the breeding of weed suppressive wheat and barley cultivars.

  6. New genetic tools for improving SIT in Ceratitis capitata: embryonic lethality and sperm marking

    Energy Technology Data Exchange (ETDEWEB)

    Schetelig, Marc F.; Wimmer, Ernst A. [Georg-August-University, Gottingen (Germany). Johann-Friedrich Blumenbach Institute of Zoology and Anthropology. Gottingen Center for Molecular Biosciences; Scolari, Francesca; Gasperi, Giuliano [Universita di Pavia (Italy). Dipt. di Biologia Animale; Handler, Ernst A. [U.S. Department of Agriculture (USDA/ARS), Gainesville, FL (United States). Agricultural Research Service. Center for Medical, Agricultural and Veterinary Entomology

    2006-07-01

    Environment friendly sterile insect technique (SIT) is being applied effectively as a component of area-wide integrated pest management (AW-IPM) for Ceratitis capitata since 1970s. Nevertheless improved biological strategies are needed to increase the efficacy of AW-IPM. Transgenic approaches should increase and widen the applicability of such programmes to different pest species. In this respect two major strategies are followed: First an approach to cause sterility was designed without interfering with spermatogenesis to maintain males and their sperm as competitive as possible. We followed a strategy, which is based on the expression of a lethal factor under the control of a promoter that is active at early blastoderm stages. The system employs the ectopic expression of a hyperactive pro apoptotic gene that causes embryo-specific lethality when driven by the tetracycline-controlled trans activator tTA under the regulation of a cellularization gene enhancer/promoter. The system has been tested successfully in Drosophila melanogaster (Horn and Wimmer 2003). We tried the direct transfer of the Drosophila system to Ceratitis capitata by injecting the respective constructs that carry Drosophila-derived promoters. Unfortunately, the cellularization specific promoters from Drosophila seem not functional in Ceratitis. Therefore, the corresponding enhancers/promoters from Ceratitis were isolated and subsequently the tTA was brought independently under the control of each enhancer/promoter region. These constructs were injected in Ceratitis for further evaluation. Second, we have engineered a medfly strain carrying a sperm marking system. This strain carries two fluorescent markers. One (turboGFP) marker is under the control of the spermatogenesis specific b2-tubulin promoter from Ceratitis and is therefore sperm specifically expressed. The second (DsRed) is under the control of the poly ubiquitin promoter of Drosophila. Released males from this strain could be

  7. New genetic tools for improving SIT in Ceratitis capitata: embryonic lethality and sperm marking

    International Nuclear Information System (INIS)

    Schetelig, Marc F.; Wimmer, Ernst A.; Scolari, Francesca; Gasperi, Giuliano; Handler, Ernst A.

    2006-01-01

    Environment friendly sterile insect technique (SIT) is being applied effectively as a component of area-wide integrated pest management (AW-IPM) for Ceratitis capitata since 1970s. Nevertheless improved biological strategies are needed to increase the efficacy of AW-IPM. Transgenic approaches should increase and widen the applicability of such programmes to different pest species. In this respect two major strategies are followed: First an approach to cause sterility was designed without interfering with spermatogenesis to maintain males and their sperm as competitive as possible. We followed a strategy, which is based on the expression of a lethal factor under the control of a promoter that is active at early blastoderm stages. The system employs the ectopic expression of a hyperactive pro apoptotic gene that causes embryo-specific lethality when driven by the tetracycline-controlled trans activator tTA under the regulation of a cellularization gene enhancer/promoter. The system has been tested successfully in Drosophila melanogaster (Horn and Wimmer 2003). We tried the direct transfer of the Drosophila system to Ceratitis capitata by injecting the respective constructs that carry Drosophila-derived promoters. Unfortunately, the cellularization specific promoters from Drosophila seem not functional in Ceratitis. Therefore, the corresponding enhancers/promoters from Ceratitis were isolated and subsequently the tTA was brought independently under the control of each enhancer/promoter region. These constructs were injected in Ceratitis for further evaluation. Second, we have engineered a medfly strain carrying a sperm marking system. This strain carries two fluorescent markers. One (turboGFP) marker is under the control of the spermatogenesis specific b2-tubulin promoter from Ceratitis and is therefore sperm specifically expressed. The second (DsRed) is under the control of the poly ubiquitin promoter of Drosophila. Released males from this strain could be

  8. Porcine sperm surface beta1,4galactosyltransferase binds to the zona pellucida but is not necessary or sufficient to mediate sperm-zona pellucida binding.

    Science.gov (United States)

    Rebeiz, M; Miller, D J

    1999-12-01

    The binding of sperm to the zona pellucida is an integral part of the mammalian fertilization process, investigated most extensively in the mouse. Several sperm receptors for the murine zona pellucida have been studied (Snell WJ, White JM. 1996. Cell 85:629-637; Wassarman PM. 1999. Cell 96:175-183), but the most compelling evidence exists for beta-1,4-galactosyltransferase (GalTase). Considering that GalTase is present on the surface of porcine sperm (Larson JL, Miller DJ. 1997. Biol Reprod 57:442-453), we investigated the role of GalTase in porcine sperm-zona binding. Sperm surface GalTase catalyzed the addition of uridine diphosphate-[(3)H]galactose to the 55 kDa group of the porcine zona pellucida proteins implicated in sperm binding, demonstrating that GalTase binds the porcine zona. The functional importance of GalTase-zona pellucida binding was tested. Addition of uridine diphosphate galactose, a substrate that completes the GalTase enzymatic reaction and disrupts GalTase mediated adhesion, had no effect on binding of sperm to porcine oocytes. Furthermore, removal of the GalTase zona ligand by incubation of oocytes with N-acetylglucosaminidase had no effect on binding of sperm to oocytes. These results suggest that GalTase is not necessary for sperm to bind to the zona pellucida. Digestion of isolated porcine zona proteins with N-acetylglucosaminidase did not affect the biological activity of soluble porcine zona proteins in competitive sperm-zona binding assays, suggesting that GalTase alone is not sufficient to mediate sperm-zona attachment. From these results, it appears that, although GalTase is able to bind porcine zona proteins, its function in porcine sperm-zona binding is not necessary or sufficient for sperm-zona binding. This supports the contention that porcine sperm-zona binding requires redundant gamete receptors. Copyright 1999 Wiley-Liss, Inc.

  9. Enhancing the Role of Educational Services of Higher Education System in the Competitive Specialists Training for Industry

    Directory of Open Access Journals (Sweden)

    Kuznetsova Olga

    2017-01-01

    Full Text Available The paper shows determination of educational services effect of higher education system to the competitive specialists training for the industry. Universities should focus their efforts on the development of innovative scientific and educational environment of the global level if they want to supply modern industry with highly qualified specialists. Despite the good results achieved in training for industry, universities should always be a step ahead in enhancing the quality of educational services. According to the findings options for professional trainings are offered; also the regional specialized educational resources launch is suggested.

  10. Drosophila melanogaster males increase the number of sperm in their ejaculate when perceiving rival males

    NARCIS (Netherlands)

    Garbaczewska, Martyna; Billeter, Jean-Christophe; Levine, Joel D.

    It is is common for females from many species to mate with multiple males within one reproductive cycle. As a result, sperm from different males come into contact in the female reproductive organs, where they compete for ova fertilization. This sperm competition appears to drive the ejaculation of a

  11. Last mated male sperm precedence in doubly mated females is not ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 92; Issue 2. Last mated male sperm precedence in doubly mated females is not ubiquitous: evidence from sperm competition in laboratory populations of Drosophila nasuta nasuta and Drosophila nasuta albomicans. B. Shruthi S. R. Ramesh. Research Note Volume 92 Issue 2 ...

  12. Low Sperm Count

    Science.gov (United States)

    ... problem such as an inherited chromosomal abnormality, a hormonal imbalance, dilated testicular veins or a condition that blocks ... Elevated temperatures impair sperm production and function. Although studies are limited and are inconclusive, frequent use of ...

  13. Polyandrous females benefit by producing sons that achieve high reproductive success in a competitive environment.

    Science.gov (United States)

    Firman, Renée C

    2011-09-22

    Females of many taxa often copulate with multiple males and incite sperm competition. On the premise that males of high genetic quality are more successful in sperm competition, it has been suggested that females may benefit from polyandry by accruing 'good genes' for their offspring. Laboratory studies have shown that multiple mating can increase female fitness through enhanced embryo viability, and have exposed how polyandry influences the evolution of the ejaculate. However, such studies often do not allow for both female mate choice and male-male competition to operate simultaneously. Here, I took house mice (Mus domesticus) from selection lines that had been evolving with (polygamous) and without (monogamous) sperm competition for 16 generations and, by placing them in free-ranging enclosures for 11 weeks, forced them to compete for access to resources and mates. Parentage analyses revealed that female reproductive success was not influenced by selection history, but there was a significant paternity bias towards males from the polygamous selection lines. Therefore, I show that female house mice benefit from polyandry by producing sons that achieve increased fitness in a semi-natural environment. This journal is © 2011 The Royal Society

  14. Enhancing Competitiveness Business Strategy of Organic Vegetables Using Analytical Hierarchy Process (AHP

    Directory of Open Access Journals (Sweden)

    Pristiana Widyastuti

    2017-09-01

    Full Text Available Public awareness about healthy lifestyles leads people to want to understand more about the food they consume. Choosing organic vegetables is one alternative choices when seeking to have a healthy body and healthy lifestyle. Unfortunately, not a lot of organic vegetable farmers in Indonesia succeed in seizing the organic vegetable market rather than the non-organic and the competition with imported organic vegetables into Indonesia prevents farmers from thriving. This study aims to: 1 Analyze the factors affecting the competitiveness of the organic vegetables market; 2 Analyze the appropriate strategy for increasing the competitiveness of the organic vegetables market; 3 Analyze the factors priority strategies for improving the competitiveness of the organic vegetables market. Porter's Generic Model and Analysis Analytical Hierarchy Process (AHP is used to determine the best strategy. The research found that organic vegetables marketing channels are still dominated by conventional market; the higher cost for intensive cultivation of organic vegetables. The main strategies are derived from the analysis is focusing on market delivery. There needs to be retailers of organic vegetables either modern or traditional to display these products. The establishment of organic vegetable outlets and online marketing that are not dependent on large retail (hypermarket become recommendations in this study. Bahasa Indonesia Abstrak: Kesadaran masyarakat tentang gaya hidup sehat memberi pilihan kepada masyarakat untuk memahami makanan yang mereka konsumsi. Pilihan sayuran organik merupakan salah satu alternatif untuk memiliki tubuh sehat dan gaya hidup sehat bagi masyarakat. Sayangnya, tidak banyak petani sayuran organik di Indonesia yang berhasil merebut pasar sayuran organik daripada non organic. Persaingan produk impor sayuran organik ke Indonesia membuat petani tidak bisa berkembang. Penelitian ini bertujuan untuk: 1 Menganalisis faktor-faktor yang

  15. Surface-mediated functional gene delivery: an effective strategy for enhancing competitiveness of endothelial cells over smooth muscle cells.

    Science.gov (United States)

    Chang, Hao; Ren, Ke-feng; Wang, Jin-Lei; Zhang, He; Wang, Bai-liang; Zheng, Shan-mei; Zhou, Yuan-yuan; Ji, Jian

    2013-04-01

    The non-biorecognition of general biomaterials and inherent biospecificity of biological systems pose key challenges to the optimal functions of medical devices. In this study, we constructed the surface-mediated functional gene delivery through layer-by-layer self-assembly of protamine sulfate (PrS) and plasmid DNA encoding hepatocyte growth factor (HGF), aiming at specific enhancing endothelial cells (EC) compeititiveness over smooth muscle cells (SMC). Characterizations of the (PrS/HGF-pDNA) multilayered films present the linear buildup with homogeneous and flat topographical feature. The amount of DNA can be easily controlled. By using these multilayered films, both human umbilical vein endothelial cells (HUVEC) and human umbilical artery smooth muscle cells (HUASMC) can be directly transfected when they contact with the multilayered films. On transfection, increasing secretion of HGF has been detected in both HUVEC and HUASMC culture, which leads to selective promotion of HUVEC proliferation. In the co-culture experiment, we also exhibit the promoted and hindered growth of HUVEC and HUASMC, respectively, which could be attributed to the inverse influence of HUVEC on HUASMC. These results collectively demonstrate that our system can be served as a powerful tool for enhancing competitiveness of EC over SMC, which opens perspectives for the regulation of intercellular competitiveness in the field of interventional therapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Enhanced competitive adsorption of CO2 and H2 on graphyne: A density functional theory study

    Science.gov (United States)

    Kwon, Hyuk Jae; Kwon, Yongju; Kim, Taeyoon; Jung, Youngsuk; Lee, Seunggeol; Cho, Min; Kwon, Soonchul

    2017-12-01

    Adsorption using carbon-based materials has been established to be a feasible method for separating carbon dioxide and hydrogen to mitigate the emission of carbon dioxide into the atmosphere and for the collection of fuel for energy sources, simultaneously. We carried out density functional theory calculation with dispersion correction to investigate the physisorption characteristics of carbon allotropes such as graphene and graphyne for the competitive adsorption of CO2 and H2. It is worth noting that the graphyne represented preferable adsorption energies, short bond lengths and energy charges for both gases, compared with the characteristics observed with graphene. We found that in graphyne, both the affinitive adsorption of CO2, and the competitive adsorption of CO2 and H2, took place at the hollow site between acetylene links, which do not exist in graphene. We demonstrate that in the presence of H2, the CO2 adsorption selectivity of graphyne is higher than that of graphene, because of the improved electronic properties resulting from the acetylene links.

  17. Brief Online Training Enhances Competitive Performance: Findings of the BBC Lab UK Psychological Skills Intervention Study.

    Science.gov (United States)

    Lane, Andrew M; Totterdell, Peter; MacDonald, Ian; Devonport, Tracey J; Friesen, Andrew P; Beedie, Christopher J; Stanley, Damian; Nevill, Alan

    2016-01-01

    In conjunction with BBC Lab UK, the present study developed 12 brief psychological skill interventions for online delivery. A protocol was designed that captured data via self-report measures, used video recordings to deliver interventions, involved a competitive concentration task against an individually matched computer opponent, and provided feedback on the effects of the interventions. Three psychological skills were used; imagery, self-talk, and if-then planning, with each skill directed to one of four different foci: outcome goal, process goal, instruction, or arousal-control. This resulted in 12 different intervention participant groups (randomly assigned) with a 13th group acting as a control. Participants (n = 44,742) completed a competitive task four times-practice, baseline, following an intervention, and again after repeating the intervention. Results revealed performance improved following practice with incremental effects for imagery-outcome, imagery-process, and self-talk-outcome and self-talk-process over the control group, with the same interventions increasing the intensity of effort invested, arousal and pleasant emotion. Arousal-control interventions associated with pleasant emotions, low arousal, and low effort invested in performance. Instructional interventions were not effective. Results offer support for the utility of online interventions in teaching psychological skills and suggest brief interventions that focus on increasing motivation, increased arousal, effort invested, and pleasant emotions were the most effective.

  18. Brief online training enhances competitive performance: Findings of the BBC Lab UK psychological skills intervention study

    Directory of Open Access Journals (Sweden)

    Andrew M Lane

    2016-03-01

    Full Text Available In conjunction with BBC Lab UK, the present study developed 12 brief psychological skill interventions for online delivery. A protocol was designed that captured data via self-report measures, used video recordings to deliver interventions, involved a competitive concentration task against an individually matched computer opponent, and provided feedback on the effects of the interventions. Three psychological skills were used; imagery, self-talk, and if-then planning, with each skill directed to one of four different foci: outcome goal, process goal, instruction, or arousal-control. This resulted in 12 different intervention participant groups (randomly assigned with a 13th group acting as a control. Participants (n = 44,742 completed a competitive task four times--practice, baseline, following an intervention, and again after repeating the intervention. Results revealed performance improved following practice with incremental effects for imagery-outcome, imagery-process, and self-talk over the control group, with the same interventions increasing the intensity of effort invested, and increasing arousal via pleasant emotions. Arousal-control interventions associated with pleasant emotions and low effort. Instructional interventions were not effective. Results offer support for the utility of online interventions in teaching psychological skills.

  19. Social dominance explains within-ejaculate variation in sperm design in a passerine bird.

    Science.gov (United States)

    Rojas Mora, Alfonso; Meniri, Magali; Ciprietti, Sabrina; Helfenstein, Fabrice

    2017-03-04

    Comparative studies suggest that sperm competition exerts stabilizing selection towards an optimal sperm design - e.g., the relative size and covariation of different sperm sections or a quantitative measure of sperm shape - that maximizes male fertility, which results in reduced levels of within-male variation in sperm morphology. Yet, these studies also reveal substantial amounts of unexplained within-ejaculate variance, and the factors presiding to the maintenance of such within-male variation in sperm design at the population level still remain to be identified. Sperm competition models predict that males should progressively invest more resources in their germline as their mating costs increase, i.e., the soma/germline allocation trade-off hypothesis. When access to fertile females is determined by social dominance, the soma/germline allocation trade-off hypothesis predicts that dominant males should invest less in the control of spermatogenesis. Hence, dominance should positively correlate with within-male variance in sperm design. In support of this hypothesis, we found that dominant house sparrow males produce ejaculates with higher levels of within-ejaculate variation in sperm design compared to subordinate males. However, after experimentally manipulating male social status, this pattern was not maintained. Our results suggest that males might control variation in sperm design according to their social status to some extent. Yet, it seems that such within-ejaculate variation in sperm design cannot be rapidly adjusted to a new status. While variation in sperm design could result from various non-exclusive sources, we discuss how strategic allocation of resources to the somatic vs. the germline functions could be an important process shaping the relationship between within-male variation in sperm design and social status.

  20. Rosiglitazone Improves Stallion Sperm Motility, ATP Content, and Mitochondrial Function.

    Science.gov (United States)

    Swegen, Aleona; Lambourne, Sarah Renay; Aitken, R John; Gibb, Zamira

    2016-11-01

    Media used for equine sperm storage often contain relatively high concentrations of glucose, even though stallion spermatozoa preferentially utilize oxidative phosphorylation (OXPHOS) over glycolysis to generate ATP and support motility. Rosiglitazone is an antidiabetic compound that enhances metabolic flexibility and glucose utilization in various cell types, but its effects on sperm metabolism are unknown. This study investigated the effects of rosiglitazone on stallion sperm function in vitro, along with the possible role of AMP-activated protein kinase (AMPK) in mediating these effects. Spermatozoa were incubated with or without rosiglitazone, GW9662 (an antagonist of peroxisome proliferator-activating receptor-gamma), and compound C (CC; an AMPK inhibitor). Sperm motility, viability, reactive oxygen species production, mitochondrial membrane potential (mMP), ATP content, and glucose uptake capacity were measured. Samples incubated with rosiglitazone displayed significantly higher motility, percentage of cells with normal mMP, ATP content, and glucose uptake capacity, while sperm viability was unaffected. The percentage of spermatozoa positive for mitochondrial ROS was also significantly lower in rosiglitazone-treated samples. AMPK localized to the sperm midpiece, and its phosphorylation, was increased in rosiglitazone-treated spermatozoa. CC decreased sperm AMPK phosphorylation and reduced sperm motility, and successfully inhibited the effects of rosiglitazone. Inclusion of rosiglitazone in a room temperature sperm storage medium maintained sperm motility above 60% for 6 days, attaining significantly higher motility than sperm stored in control media. The ability of rosiglitazone to substantially alleviate the time-dependent deterioration of stallion spermatozoa by diverting metabolism away from OXPHOS and toward glycolysis has novel implications for the long-term, functional preservation of these cells. © 2016 by the Society for the Study of Reproduction

  1. Pentoxifylline effects on capacitation and fertility of stallion epididymal sperm.

    Science.gov (United States)

    Guasti, P N; Monteiro, G A; Maziero, R R D; Carmo, M T; Dell'Aqua, J A; Crespilho, A M; Rifai, E A; Papa, F O

    2017-04-01

    The aims of this study were to determinate whether pentoxifylline (PTX) increases the motion parameters of fresh and frozen-thawed equine epididymal spermatozoa, to evaluate the tyrosine phosphorylation of frozen-thawed epididymal sperm in the presence of PTX and to determine whether the PTX-treatment of stallion epididymal sperm prior to freezing improves the fertility response of mares to a reduced number of spermatozoa per insemination dose. Fifty epididymis were flushed with a skim milk based extender with or without PTX. The pre-treatment with PTX enhanced the sperm motility after being harvested (Psperm kinematics between control and treated samples (P>0.05). Plasma membrane integrity did not differ between control and PTX group after recovery and after thawing (P>0.05), as observed in tyrosine phosphorylation, which the PTX treatment did not alter the percentage of tail-associated immunofluorescence of cryopreserved epididymal sperm (P>0.05). For the fertility trial, different insemination groups were tested: 800×10 6 epididymal sperm (C800); 100×10 6 epididymal sperm (C100); 100×10 6 epididymal sperm recovered in an extender containing PTX (PTX100). The conception rates for C800; C100 and PTX100 were 68.7% (11/16); 31.5% (5/16) and 50% (8/16), respectively. The conception rate did not differ among groups (P>0.05), however, a low number of animals was used in this study. A trend toward significance (P=0.07) was observed between C800 and C100 groups. In conclusion, PTX has no deleterious effect on sperm motility, viability and capacitation of cryopreserved stallion epididymal sperm. The conventional artificial insemination with 100×10 6 sperm recovered with PTX ensures acceptable conception rates and maximize the limited number of doses of cryopreserved stallion epididymal sperm. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Human sperm steer with second harmonics of the flagellar beat.

    Science.gov (United States)

    Saggiorato, Guglielmo; Alvarez, Luis; Jikeli, Jan F; Kaupp, U Benjamin; Gompper, Gerhard; Elgeti, Jens

    2017-11-10

    Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic. The superposition of harmonics breaks the beat symmetry temporally rather than spatially. As a result, sperm rotate around the tethering point. The rotation velocity is determined by the second-harmonic amplitude and phase. Stimulation with the female sex hormone progesterone enhances the second-harmonic contribution and, thereby, modulates sperm rotation. Higher beat frequency components exist in other flagellated cells; therefore, this steering mechanism might be widespread and could inspire the design of synthetic microswimmers.

  3. Defense Acquisition Policy and Defense Industrial Base Reinforcement Strategy - Enhancing the International Competitiveness of the Korean National Defense Industry

    National Research Council Canada - National Science Library

    Lee, Dae O

    2008-01-01

    ...) through competitiveness analysis is required. Thus, it is necessary to develop appropriate models for analyzing the Korean NDI and to conduct competitiveness analysis by using the developed model...

  4. A harmonized and efficient clinical research environment would benefit patients and enhance European competitiveness. Commentary.

    Science.gov (United States)

    Amato, Antonino; Aringhieri, Eugenio; Boccia, Stefania; Buccella, Filippo; Gorini, Barbara; Gramaglia, Donatella; Masetti, Riccardo; Rossi, Paolo; Pelicci, Pier Giuseppe

    2017-01-01

    The forthcoming implementation of the European Clinical Trial Regulation (Regulation (EU) No. 536/2014), which is expected to facilitate the conduct of clinical trials across the European Union, will require National Authorities to create the best conditions for the implementation of the new Regulation through national guidelines, so that sponsors may reconsider Europe as a prime location for planning clinical trials. During a meeting titled "Innovation in Clinical Research", an expert panel discussed potential local advances fostering competitiveness of European clinical research with representatives of the pharmaceutical industry, patient organisations and Italian regulatory agency in view of the forthcoming implementation of (EU) No. 536/2014 on clinical trials of medicinal products. In this article we summarise the findings of the meeting, describe features characterising clinical research patterns and offer some suggestions on the possible involvement of all stakeholders in order to foster research innovation and allow the timely access to novel medicines for patients.

  5. Testosterone is associated with cooperation during intergroup competition by enhancing parochial altruism

    Directory of Open Access Journals (Sweden)

    Luise eReimers

    2015-06-01

    Full Text Available The steroid hormone testosterone is widely associated with negative behavioral effects, such as aggression or dominance. However, recent studies applying economic exchange tasks revealed conflicting results. While some point to a prosocial effect of testosterone by increasing altruistic behavior, others report that testosterone promotes antisocial tendencies. Taking into account additional factors such as parochial altruism (i.e., ingroup favoritism and outgroup hostility might help to explain this contradiction. First evidence for a link between testosterone and parochial altruism comes from recently reported data of male soccer fans playing the ultimatum game. In this study high levels of endogenous testosterone predicted increased altruistic punishment during outgroup interactions and at the same time heightened ingroup generosity. Here, we report findings of another experimental task, the prisoner’s dilemma, applied in the same context to examine the role of testosterone on parochial tendencies in terms of cooperation. In this task, fifty male soccer fans were asked to decide whether or not they wanted to cooperate with partners marked as either fans of the subject’s own favorite team (ingroup or fans of other teams (outgroups. Our results show that high testosterone levels were associated with increased ingroup cooperation during intergroup competition. In addition, subjects displaying a high degree of parochialism during intergroup competition had significantly higher levels of testosterone than subjects who did not differentiate much between the different groups. In sum, the present data demonstrate that the behavioral effects of testosterone are not limited to aggressive and selfish tendencies but may imply prosocial aspects depending on the context. By this means, our results support the previously reported findings on testosterone-dependent intergroup bias and indicate that this social hormone might be an important factor driving

  6. Mutation of praR in Rhizobium leguminosarum enhances root biofilms, improving nodulation competitiveness by increased expression of attachment proteins.

    Science.gov (United States)

    Frederix, Marijke; Edwards, Anne; Swiderska, Anna; Stanger, Andrew; Karunakaran, Ramakrishnan; Williams, Alan; Abbruscato, Pamela; Sanchez-Contreras, Maria; Poole, Philip S; Downie, J Allan

    2014-08-01

    In Rhizobium leguminosarum bv. viciae, quorum-sensing is regulated by CinR, which induces the cinIS operon. CinI synthesizes an AHL, whereas CinS inactivates PraR, a repressor. Mutation of praR enhanced biofilms in vitro. We developed a light (lux)-dependent assay of rhizobial attachment to roots and demonstrated that mutation of praR increased biofilms on pea roots. The praR mutant out-competed wild-type for infection of pea nodules in mixed inoculations. Analysis of gene expression by microarrays and promoter fusions revealed that PraR represses its own transcription and mutation of praR increased expression of several genes including those encoding secreted proteins (the adhesins RapA2, RapB and RapC, two cadherins and the glycanase PlyB), the polysaccharide regulator RosR, and another protein similar to PraR. PraR bound to the promoters of several of these genes indicating direct repression. Mutations in rapA2, rapB, rapC, plyB, the cadherins or rosR did not affect the enhanced root attachment or nodule competitiveness of the praR mutant. However combinations of mutations in rapA, rapB and rapC abolished the enhanced attachment and nodule competitiveness. We conclude that relief of PraR-mediated repression determines a lifestyle switch allowing the expression of genes that are important for biofilm formation on roots and the subsequent initiation of infection of legume roots. © 2014 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

  7. Mutation of praR in Rhizobium leguminosarum enhances root biofilms, improving nodulation competitiveness by increased expression of attachment proteins

    Science.gov (United States)

    Frederix, Marijke; Edwards, Anne; Swiderska, Anna; Stanger, Andrew; Karunakaran, Ramakrishnan; Williams, Alan; Abbruscato, Pamela; Sanchez-Contreras, Maria; Poole, Philip S; Downie, J Allan

    2014-01-01

    In Rhizobium leguminosarum bv. viciae, quorum-sensing is regulated by CinR, which induces the cinIS operon. CinI synthesizes an AHL, whereas CinS inactivates PraR, a repressor. Mutation of praR enhanced biofilms in vitro. We developed a light (lux)-dependent assay of rhizobial attachment to roots and demonstrated that mutation of praR increased biofilms on pea roots. The praR mutant out-competed wild-type for infection of pea nodules in mixed inoculations. Analysis of gene expression by microarrays and promoter fusions revealed that PraR represses its own transcription and mutation of praR increased expression of several genes including those encoding secreted proteins (the adhesins RapA2, RapB and RapC, two cadherins and the glycanase PlyB), the polysaccharide regulator RosR, and another protein similar to PraR. PraR bound to the promoters of several of these genes indicating direct repression. Mutations in rapA2, rapB, rapC, plyB, the cadherins or rosR did not affect the enhanced root attachment or nodule competitiveness of the praR mutant. However combinations of mutations in rapA, rapB and rapC abolished the enhanced attachment and nodule competitiveness. We conclude that relief of PraR-mediated repression determines a lifestyle switch allowing the expression of genes that are important for biofilm formation on roots and the subsequent initiation of infection of legume roots. PMID:24942546

  8. Subversive practices of sperm donation - globalizing Danish sperm

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    During the past two decades, Denmark has developed in to an important destination for fertility travellers in need of donor sperm. Furthermore, two of the largest sperm banks in Europe have been established in Denmark, exporting sperm globally. This development has taken place at the same time...

  9. Postcopulatory sexual selection is associated with reduced variation in sperm morphology.

    Science.gov (United States)

    Calhim, Sara; Immler, Simone; Birkhead, Tim R

    2007-05-02

    The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa. However, previous studies have focused almost exclusively on the influence of sperm competition on variation among species. In this study we tested the hypothesis that intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds. Using two proxy measures of sperm competition level, (i) relative testes size and (ii) extrapair paternity level, we found strong evidence that intermale variation in sperm morphology is negatively associated with the degree of postcopulatory sexual selection, independently of phylogeny. Our results show that the role of postcopulatory sexual selection in the evolution of sperm morphology extends to an intraspecific level, reducing the variation towards what might be a species-specific 'optimum' sperm phenotype. This finding suggests that while postcopulatory selection is generally directional (e.g., favouring longer sperm) across avian species, it also acts as a stabilising evolutionary force within species under intense selection, resulting in reduced variation in sperm morphology traits. We discuss some potential evolutionary mechanisms for this pattern.

  10. Postcopulatory sexual selection is associated with reduced variation in sperm morphology.

    Directory of Open Access Journals (Sweden)

    Sara Calhim

    2007-05-01

    Full Text Available The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa. However, previous studies have focused almost exclusively on the influence of sperm competition on variation among species. In this study we tested the hypothesis that intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds.Using two proxy measures of sperm competition level, (i relative testes size and (ii extrapair paternity level, we found strong evidence that intermale variation in sperm morphology is negatively associated with the degree of postcopulatory sexual selection, independently of phylogeny.Our results show that the role of postcopulatory sexual selection in the evolution of sperm morphology extends to an intraspecific level, reducing the variation towards what might be a species-specific 'optimum' sperm phenotype. This finding suggests that while postcopulatory selection is generally directional (e.g., favouring longer sperm across avian species, it also acts as a stabilising evolutionary force within species under intense selection, resulting in reduced variation in sperm morphology traits. We discuss some potential evolutionary mechanisms for this pattern.

  11. Sperm removal during copulation confirmed in the oldest extant damselfly, Hemiphlebia mirabilis

    Directory of Open Access Journals (Sweden)

    Adolfo Cordero-Rivera

    2016-05-01

    Full Text Available Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family, Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour. Males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomise. Copulation is short (range 4.1–18.7 min, and occurs in two sequential stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The male genital ligula matches the size and form of female genitalia, and ends by two horns covered by back-oriented spines. The volume of sperm in females before copulation was 2.7 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, possibly dating back to the Permian.

  12. No evidence of conpopulation sperm precedence between allopatric populations of house mice.

    Directory of Open Access Journals (Sweden)

    Renée C Firman

    Full Text Available Investigations into the evolution of reproductive barriers have traditionally focused on closely related species, and the prevalence of conspecific sperm precedence. The effectiveness of conspecific sperm precedence at limiting gene exchange between species suggests that gametic isolation is an important component of reproductive isolation. However, there is a paucity of tests for evidence of sperm precedence during the earlier stages of divergence, for example among isolated populations. Here, we sourced individuals from two allopatric populations of house mice (Mus domesticus and performed competitive in vitro fertilisation assays to test for conpopulation sperm precedence specifically at the gametic level. We found that ova population origin did not influence the outcome of the sperm competitions, and thus provide no evidence of conpopulation or heteropopulation sperm precedence. Instead, we found that males from a population that had evolved under a high level of postcopulatory sexual selection consistently outcompeted males from a population that had evolved under a relatively lower level of postcopulatory sexual selection. We standardised the number of motile sperm of each competitor across the replicate assays. Our data therefore show that competitive fertilizing success was directly attributable to differences in sperm fertilizing competence.

  13. Healthy Sperm: Improving Your Fertility

    Science.gov (United States)

    Healthy Lifestyle Getting pregnant Healthy sperm aren't always a given. Understand how lifestyle factors can affect your ... of retrieving and storing sperm before treatment. Adopting healthy lifestyle practices to promote your fertility — and avoiding things ...

  14. Proteins involved in motility and sperm-egg interaction evolve more rapidly in mouse spermatozoa.

    Directory of Open Access Journals (Sweden)

    Alberto Vicens

    Full Text Available Proteomic studies of spermatozoa have identified a large catalog of integral sperm proteins. Rapid evolution of these proteins may underlie adaptive changes of sperm traits involved in different events leading to fertilization, although the selective forces underlying such rapid evolution are not well understood. A variety of selective forces may differentially affect several steps ending in fertilization, thus resulting in a compartmentalized adaptation of sperm proteins. Here we analyzed the evolution of genes associated to various events in the sperm's life, from sperm formation to sperm-egg interaction. Evolutionary analyses were performed on gene sequences from 17 mouse strains whose genomes have been sequenced. Four of these are derived from wild Mus musculus, M. domesticus, M. castaneus and M. spretus. We found a higher proportion of genes exhibiting a signature of positive selection among those related to sperm motility and sperm-egg interaction. Furthermore, sperm proteins involved in sperm-egg interaction exhibited accelerated evolution in comparison to those involved in other events. Thus, we identified a large set of candidate proteins for future comparative analyses of genotype-phenotype associations in spermatozoa of species subjected to different sexual selection pressures. Adaptive evolution of proteins involved in motility could be driven by sperm competition, since this selective force is known to increase the proportion of motile sperm and their swimming velocity. On the other hand, sperm proteins involved in gamete interaction could be coevolving with their egg partners through episodes of sexual selection or sexual conflict resulting in species-specific sperm-egg interactions and barriers preventing interspecies fertilization.

  15. First Production of Larvae Using Cryopreserved Sperm: Effects of Preservation Temperature and Cryopreservation on European Eel Sperm Fertilization Capacity.

    Science.gov (United States)

    Asturiano, J F; Sørensen, S R; Pérez, L; Lauesen, P; Tomkiewicz, J

    2016-08-01

    Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols. Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few larvae ('cryolarvae') were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success. © 2016 Blackwell Verlag GmbH.

  16. How internal processes benefit from IT investments and therefore enhance company's competitiveness - A case study of Slovenian small and medium sized companies

    OpenAIRE

    Habjan, Andreja; Popovic, Ales

    2007-01-01

    In the paper we presented a case of how IT impacts business process change and how can this enhance competitiveness. The case deals with implementation of internal server for use of documentation exchange in Slovenian small and medium sized companies and provides a framework of key factors of followed changes in inter processes that enabled better competitive position of the organizations taking part of the study. publishersversion published

  17. Sperm whale clicks

    DEFF Research Database (Denmark)

    Møhl, Bertel; Wahlberg, Magnus; Madsen, Peter T.

    2000-01-01

    . A sound generator weighing upward of 10 tons and with a cross-section of 1 m is expected to generate high-intensity, directional sounds. This prediction from the Norris and Harvey theory is not supported by published data for sperm whale clicks ~source levels of 180 dB re 1 mPa and little, if any....... This implicates sonar as a possible function of the clicks. Thus, previously published properties of sperm whale clicks underestimate the capabilities of the sound generator and therefore cannot falsify the Norris and Harvey theory.......In sperm whales ~Physeter catodon L. 1758! the nose is vastly hypertrophied, accounting for about one-third of the length or weight of an adult male. Norris and Harvey @in Animal Orientation and Navigation, NASA SP-262 ~1972!, pp. 397–417# ascribed a sound-generating function to this organ complex...

  18. Substrate-mediated delivery of gene complex nanoparticles via polydopamine coating for enhancing competitiveness of endothelial cells.

    Science.gov (United States)

    Li, Bo-Chao; Chang, Hao; Ren, Ke-Feng; Ji, Jian

    2016-11-01

    Substrate-mediated delivery of functional plasmid DNA (pDNA) has been proven to be a promising strategy to promote competitiveness of endothelial cells (ECs) over smooth muscle cells (SMCs), which is beneficial to inducing fast endothelialization of implanted vascular devices. Thus, it is of great importance to develop universal approaches with simplicity and easiness to immobilize DNA complex nanoparticles on substrates. In this study, the bioinspired polydopamine (PDA) coating was employed in immobilization of DNA complex nanoparticles, which were composed of protamine (PrS) and plasmid DNA encoding with hepatocyte growth factor (HGF-pDNA) gene. We demonstrated that the DNA complex nanoparticles can be successfully immobilized onto the PDA surface. Consequently, the HGF expression of both ECs and SMCs were significantly improved when they cultured on the DNA complex nanoparticles-immobilized substrates. Furthermore, EC proliferation was specifically promoted due to bioactivity of HGF, leading to an enhancement of EC competitiveness over SMCs. Our findings demonstrated the substrate-mediated functional gene nanoparticle delivery through PDA coating as a simple and efficient approach. It may hold great potential in the field of interventional cardiovascular implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Sperm motility in fish: technical applications and perspectives through CASA-Mot systems.

    Science.gov (United States)

    Gallego, V; Asturiano, J F

    2018-03-09

    Although a relatively high number of sperm quality biomarkers have been reported over the years in several fish species, sperm motility is nowadays considered the best biomarker for fish spermatozoa. The first scientific reports focusing on fish sperm motility date from a century ago, but the objective assessment allowed by computer-aided sperm analysis (CASA-Mot) systems was not applied to fish species until the mid-1980s. Since then, a high number of sperm kinetic parameters from more than 170 fish species have been reported in more than 700 scientific articles, covering a wide range of topics, such as sperm physiology, sperm storage, broodstock management, the phenomenon of sperm competition, ecotoxicology and understanding the life cycle of the species. The sperm kinetic parameters provided by CASA-Mot systems can serve as powerful and useful tools for aquaculture and ecological purposes, and this review provides an overview of the major research areas in which fish sperm motility assessment by a CASA-Mot system has been used successfully.

  20. Application of new phenolic antioxidants for cryopreservation of sturgeon sperm.

    Science.gov (United States)

    Osipova, V P; Berberova, N T; Gazzaeva, R A; Kudryavtsev, K V

    2016-04-01

    Heterocyclic derivatives of butylated hydroxytoluene (BHT) were studied as cryoprotectants of the basic media for cryopreservation of the Russian sturgeon sperm. Rates of lipid peroxidation of sturgeon sperm before and after cryopreservation were reduced in the presence of the studied compounds, exceeding the effects of BHT and water-soluble analogue of vitamin E, trolox. The most efficient antioxidant has the effective concentration of 0.1 mM. Novel antioxidant agents as cryomedium supplements not only reduced the level of lipid peroxidation, but also enhanced the translational motility of the sperm of the Russian sturgeon after defrosting. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Subversive practices of sperm donation - globalizing Danish sperm

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    During the past two decades, Denmark has developed in to an important destination for fertility travellers in need of donor sperm. Furthermore, two of the largest sperm banks in Europe have been established in Denmark, exporting sperm globally. This development has taken place at the same time...... as the use of donated sperm continuously has been debated as an ethical issue, and increasingly been regulated. In this presentation I will discuss how Denmark became a destination for fertility travelling (sperm donation) as a result of various subversive strategies of family making. The article inquires...... into how the bending of boundaries by “inappropriate parents”, fertility travellers, private sperm banks and fertility clinics have been part in negotiating the changes of the legislation in practice, and thus been part of developing a Danish industry of sperm banking. The presentation is based on a multi...

  2. Enhancing the competitiveness of skilled construction workers through collaborative education and training

    Science.gov (United States)

    Dardiri, Ahmad; Sutrisno, Kuncoro, Tri; Ichwanto, Muhamad Aris; Suparji

    2017-09-01

    Professionalism of construction workers is one of the keys to the success of infrastructure development projects. The professionalism of the workforce is demonstrated through the possession of expertise competence certificate (SKA) and/or certificates of skills (SKT) issued formally through competency tests by the National Construction Cervices Development Agency (LPJKN). The magnitude of the national skilled manpower needs has not been able to meet the availability of professional workforce. Strategies to develop the quality of resources require sufficient information on the characteristics of the resources themselves, facilities, constraints, stakeholder support, regulations, and socioeconomic as well as cultural conditions. The problems faced by Indonesia in improving the competitiveness of skilled construction workers are (1) how the level of professionalism of skill workers in construction field, (2) what the constrains on improving the quality of skilled construction workers,and(3) how the appropriate model of education and training skillfull construction work. The study was designed with quantitative and qualitative approaches. Quantitative methods were used to describe the profile of sklill constructions worker. Qualitative methods were used toidentify constraintsin improving the qualityof skilled labor, as well as formulate a viable collaborative education and training model for improving the quality of skill labor. Data were collected by documentation, observation, and interview. The result of the study indicate theat (1) the professionalism knowledge of skilled constructions worker are in still low condition, (2) the constrain faced in developing the quality of skilled construction labor cover economic and structural constrains, and (3) collaborative eduction and training model can improve the quality ods skilld labor contructions.

  3. Exploratory studies into strategies to enhance innovation-driven international competitiveness in a port context : Toward ambidextrous ports

    NARCIS (Netherlands)

    R.M.A. Hollen (Rick)

    2015-01-01

    markdownabstractResearch has highlighted that firms competing in dynamic environments have to balance exploitative (efficiency-directed) activities with explorative (innovation-directed) ones in order to remain internationally competitive. In economically advanced countries, whose competitiveness is

  4. Exogenous testosterone in women enhances and inhibits competitive decision-making depending on victory-defeat experience and trait dominanc

    NARCIS (Netherlands)

    Mehta, P.H.; Son, V. van; Welker, K.M.; Prasad, S.; Sanfey, A.G.; Smidts, A.; Roelofs, K.

    2015-01-01

    The present experiment tested the causal impact of testosterone on human competitive decision-making. According to prevailing theories about testosterone's role in social behavior, testosterone should directly boost competitive decisions. But recent correlational evidence suggests that

  5. Sperm head's birefringence: a new criterion for sperm selection.

    Science.gov (United States)

    Gianaroli, Luca; Magli, M Cristina; Collodel, Giulia; Moretti, Elena; Ferraretti, Anna P; Baccetti, Baccio

    2008-07-01

    To investigate the characteristics of birefringence in human sperm heads and apply polarization microscopy for sperm selection at intracytoplasmic sperm injection (ICSI). Prospective randomized study. Reproductive Medicine Unit, Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. A total of 112 male patients had birefringent sperm selected for ICSI (study group). The clinical outcome was compared with that obtained in 119 couples who underwent a conventional ICSI cycle (control group). The proportion of birefringent spermatozoa was evaluated before and after treatment in relation to the sperm sample quality. Embryo development and clinical outcome in the study group were compared with those in the controls. Proportion of birefringent sperm heads, rates of fertilization, cleavage, pregnancy, implantation, and ongoing implantation. The proportion of birefringent spermatozoa was significantly higher in normospermic samples when compared with oligoasthenoteratospermic samples with no progressive motility and testicular sperm extraction samples. Although fertilization and cleavage rates did not differ between the study and control groups, in the most severe male factor condition (oligoasthenoteratospermic with no progressive motility and testicular sperm extraction), the rates of clinical pregnancy, ongoing pregnancy, and implantation were significantly higher in the study group versus the controls. The analysis of birefringence in the sperm head could represent both a diagnostic tool and a novel method for sperm selection.

  6. The effect of antioxidants on sperm motility activation in the Booroolong frog.

    Science.gov (United States)

    Keogh, L M; Byrne, P G; Silla, A J

    2017-08-01

    Motile sperm can generate high levels of reactive oxygen species (ROS) post activation, and ROS can quickly accumulate to levels that impair motility and fertilising ability. The addition of antioxidants to sperm suspensions has been suggested as a means of reducing oxidative stress and enhancing sperm motility during and after sperm storage. Despite this, very few studies have attempted to experimentally test the effects of antioxidants on sperm motility activation in animals that use an external mode of fertilisation, espcially in amphibians. The present study aimed to investigate the effect of vitamin C and vitamin E on sperm motility activation in the Booroolong frog. Spermatozoa were activated in media containing either vitamin C (0, 0.05, 0.10, 0.15, 0.20, 0.25μgμL -1 ) or vitamin E (0, 0.25, 0.50, 0.75, 1.0, 1.25 1.50, 1.75μgμL -1 ). Sperm performance parameters (percent motility and velocity) were assessed using CASA at 0, 1, 2, 3, 4, 5 and 6h post-activation. Contrary to expectations, vitamin C supplementation was detrimental to sperm motility across all tested concentrations, while vitamin E had no effect. Further investigation on the endogenous antioxidant system of anuran sperm is required to ascertain whether alternative antioxidants may be more suitable at reducing ROS produced during sperm activation and improving sperm motility activation in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Aggregation of human sperm at higher temperature is due to hyperactivation.

    Science.gov (United States)

    Keppler, E L; Chan, P J; Patton, W C; King, A

    1999-01-01

    Chemotaxis of sperm cells to chemicals and hormones, such as progesterone, helps us to understand the concept of sperm transport. Here, the hypothesis was that heat increased sperm hyperactive motility, which caused the sperm to aggregate at the higher temperature. The objectives were (1) to determine the concentration of sperm at both halves of an artificial female reproductive tract made from a hermetically sealed cryopreservation straw filled with culture medium and placed with each end at different temperatures, and (2) to analyze the motility or kinematic parameters and hyperactivation of sperm found at the different temperatures. Cryopreserved-thawed human donor sperm (N = 6) were pooled and processed through 2-layer colloid solution. Analyses of the motile sperm were carried out and the washed sperm were homogeneously mixed and pipetted into several 0.5-mL French cryopreservation straws and heat-sealed. The control substance, consisting of acid-treated sperm, was also placed in several straws. The plastic straws of sperm were placed half at 23 degrees C and half was at either 37 or 40 degrees C. After 4 h, sperm at different sections of the straws were analyzed using the Hamilton Thorn motility analyzer (HTM-C). After 4 h of incubation, the concentration of sperm was doubled at the 40 degrees C heated half of the straw when compared with the other half of the straw at 23 degrees C. There were no differences in sperm concentration in the straw kept half at 37 degrees C and half at 23 degrees C. There were significantly higher percent motility, mean average path velocity, straight line velocity, lateral head displacement, and percent hyperactivation in sperm at the 40 degrees C temperature. The aggregation of sperm at the higher temperature of 40 degrees C may be due to enhanced motility, increased sperm velocities, and a 10-fold increase in hyperactivation at that temperature. The 37 degrees C temperature was not sufficient to attract sperm. Sperm cells

  8. Diversifying evolution of competitiveness

    NARCIS (Netherlands)

    Baldauf, Sebastian A.; Engqvist, Leif; Weissing, Franz J.

    2014-01-01

    In many species, individuals express phenotypic characteristics that enhance their competitiveness, that is, the ability to acquire resources in competition with others. Moreover, the degree of competitiveness varies considerably across individuals and in time. By means of an evolutionary model, we

  9. Modelling a tethered mammalian sperm cell undergoing hyperactivation

    KAUST Repository

    Curtis, M.P.

    2012-09-01

    The beat patterns of mammalian sperm flagella can be categorised into two different types. The first involves symmetric waves propagating down the flagellum with a net linear propulsion of the sperm cell. The second, hyperactive, waveform is classified by vigorous asymmetric waves of higher amplitude, lower wavenumber and frequency propagating down the flagellum resulting in highly curved trajectories. The latter beat pattern is part of the capacitation process whereby sperm prepare for the prospective penetration of the zona pellucida and fusion with the egg. Hyperactivation is often observed to initiate as sperm escape from epithelial and ciliary bindings formed within the isthmic regions of the female oviducts, leading to a conjecture in the literature that this waveform is mechanically important for sperm escape. Hence, we explore the mechanical effects of hyperactivation on a tethered sperm, focussing on a Newtonian fluid. Using a resistive force theory model we demonstrate that hyperactivation can indeed generate forces that pull the sperm away from a tethering point and consequently a hyperactivated sperm cell bound to an epithelial surface need not always be pushed by its flagellum. More generally, directions of the forces generated by tethered flagella are insensitive to reductions in beat frequency and the detailed flagellar responses depend on the nature of the binding at the tethering point. Furthermore, waveform asymmetry and amplitude increases enhance the tendency for a tethered flagellum to start tugging on its binding. The same is generally predicted to be true for reductions in the wavenumber of the flagellum beat, but not universally so, emphasising the dynamical complexity of flagellar force generation. Finally, qualitative observations drawn from experimental data of human sperm bound to excised female reproductive tract are also presented and are found to be consistent with the theoretical predictions. © 2012 Elsevier Ltd.

  10. Nanoparticle incorporation of melittin reduces sperm and vaginal epithelium cytotoxicity.

    Directory of Open Access Journals (Sweden)

    Andrew P Jallouk

    Full Text Available Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free melittin is limited by its cytotoxicity, incorporation of melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001. However, melittin nanoparticles were not cytotoxic to sperm (p = 0.42 or vaginal epithelium (p = 0.48 at an equivalent melittin concentration of 10 µM. Thus, nanoparticle formulation of melittin reduced melittin cytotoxicity fivefold and prevented melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent melittin concentrations ≥20 µM (p<0.001 and were toxic to sperm at equivalent melittin concentrations ≥40 µM (p<0.001. Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy.

  11. Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity

    Science.gov (United States)

    Jallouk, Andrew P.; Moley, Kelle H.; Omurtag, Kenan; Hu, Grace; Lanza, Gregory M.; Wickline, Samuel A.; Hood, Joshua L.

    2014-01-01

    Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free melittin is limited by its cytotoxicity, incorporation of melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001). However, melittin nanoparticles were not cytotoxic to sperm (p = 0.42) or vaginal epithelium (p = 0.48) at an equivalent melittin concentration of 10 µM. Thus, nanoparticle formulation of melittin reduced melittin cytotoxicity fivefold and prevented melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent melittin concentrations ≥20 µM (p<0.001) and were toxic to sperm at equivalent melittin concentrations ≥40 µM (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy. PMID:24748389

  12. Polymorphism of transferrin of carp seminal plasma: relationship to blood transferrin and sperm motility characteristics.

    Science.gov (United States)

    Wojtczak, Mariola; Dietrich, Grzegorz J; Irnazarow, Ilgiz; Jurecka, Patrycja; Słowińska, Mariola; Ciereszko, Andrzej

    2007-12-01

    Transferrin (Tf) is a major protein of carp (Cyprinus carpio) seminal plasma. Its relationship with milt quality is unknown. In this study, we sought to determine if Tf is polymorphic in carp seminal plasma and if this polymorphism is related to sperm motility characteristics. We screened males of purebred common carp line (Polish line R6) for Tf polymorphism in blood plasma. The majority of Tf genotypes represented only DD and DG variants. We then collected milt from preselected DD and DG genotypes and tested their sperm motility characteristics using computer-aided sperm analysis (CASA). Tf polymorphism in seminal plasma was found to be identical with that of blood. However, the relationships between Tf polymorphism and iron metabolic parameters were different for blood and semen. These data suggest different regulation of Tf in liver and testis. We found substantial differences in sperm motility characteristics between both genotypes. Spermatozoa of DG males were characterized by lower curvilinear velocity (VCL), amplitude of lateral head displacement (ALH), higher linearity (LIN) and straightness (STR) of movement as compared to DD males. No differences were found in other sperm characteristics such as sperm concentration and percentage of sperm motility. Our results suggest that sperm motility parameters are related to Tf polymorphism and therefore this polymorphism may be related to sperm competitive ability.

  13. How sexual selection can drive the evolution of costly sperm ornamentation

    Science.gov (United States)

    Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott

    2016-05-01

    Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.

  14. Diversifying evolution of competitiveness.

    Science.gov (United States)

    Baldauf, Sebastian A; Engqvist, Leif; Weissing, Franz J

    2014-10-29

    In many species, individuals express phenotypic characteristics that enhance their competitiveness, that is, the ability to acquire resources in competition with others. Moreover, the degree of competitiveness varies considerably across individuals and in time. By means of an evolutionary model, we provide an explanation for this finding. We make the assumption that investment into competitiveness enhances the probability to acquire a high-quality resource, but at the same time reduces the ability of exploiting acquired resources with maximal efficiency. The model reveals that under a broad range of conditions competitiveness either converges to a polymorphic state, where individuals differing in competitive ability stably coexist, or is subject to perpetual transitions between periods of high and low competitiveness. The dynamics becomes even more complex if females can evolve preferences for (or against) competitive males. In extreme cases, such preferences can even drive the population to extinction.

  15. Recent advances in bird sperm morphometric analysis and its role in male gamete characterization and reproduction technologies

    Directory of Open Access Journals (Sweden)

    Julian Santiago-Moreno

    2016-01-01

    Full Text Available Postcopulatory sexual selection through sperm competition may be an important evolutionary force affecting many reproductive traits, including sperm morphometrics. Environmental factors such as pollutants, pesticides, and climate change may affect different sperm traits, and thus reproduction, in sensitive bird species. Many sperm-handling processes used in assisted reproductive techniques may also affect the size of sperm cells. The accurately measured dimensions of sperm cell structures (especially the head can thus be used as indicators of environmental influences, in improving our understanding of reproductive and evolutionary strategies, and for optimizing assisted reproductive techniques (e.g., sperm cryopreservation for use with birds. Computer-assisted sperm morphometry analysis (CASA-Morph provides an accurate and reliable method for assessing sperm morphometry, reducing the problem of subjectivity associated with human visual assessment. Computerized systems have been standardized for use with semen from different mammalian species. Avian spermatozoa, however, are filiform, limiting their analysis with such systems, which were developed to examine the approximately spherical heads of mammalian sperm cells. To help overcome this, the standardization of staining techniques to be used in computer-assessed light microscopical methods is a priority. The present review discusses these points and describes the sperm morphometric characteristics of several wild and domestic bird species.

  16. Recent advances in bird sperm morphometric analysis and its role in male gamete characterization and reproduction technologies

    Science.gov (United States)

    Santiago-Moreno, Julian; Esteso, Milagros Cristina; Villaverde-Morcillo, Silvia; Toledano-Díaz, Adolfo; Castaño, Cristina; Velázquez, Rosario; López-Sebastián, Antonio; Goya, Agustín López; Martínez, Javier Gimeno

    2016-01-01

    Postcopulatory sexual selection through sperm competition may be an important evolutionary force affecting many reproductive traits, including sperm morphometrics. Environmental factors such as pollutants, pesticides, and climate change may affect different sperm traits, and thus reproduction, in sensitive bird species. Many sperm-handling processes used in assisted reproductive techniques may also affect the size of sperm cells. The accurately measured dimensions of sperm cell structures (especially the head) can thus be used as indicators of environmental influences, in improving our understanding of reproductive and evolutionary strategies, and for optimizing assisted reproductive techniques (e.g., sperm cryopreservation) for use with birds. Computer-assisted sperm morphometry analysis (CASA-Morph) provides an accurate and reliable method for assessing sperm morphometry, reducing the problem of subjectivity associated with human visual assessment. Computerized systems have been standardized for use with semen from different mammalian species. Avian spermatozoa, however, are filiform, limiting their analysis with such systems, which were developed to examine the approximately spherical heads of mammalian sperm cells. To help overcome this, the standardization of staining techniques to be used in computer-assessed light microscopical methods is a priority. The present review discusses these points and describes the sperm morphometric characteristics of several wild and domestic bird species. PMID:27678467

  17. Sperm cell proteomics.

    Science.gov (United States)

    Oliva, Rafael; de Mateo, Sara; Estanyol, Josep Maria

    2009-02-01

    The spermatozoon is an accessible cell which can be easily purified and therefore it is particularly well suited for proteomic analysis. It is also an extremely differentiated cell with very marked genetic, cellular, functional and chromatin changes as compared to other cells, and has profound implications for fertility, embryo development and heredity. The recent developments in MS have boosted the potential for identification and study of the sperm proteins. Catalogues of hundreds to thousands of spermatozoan proteins in human and in model species are becoming available setting up the basis for subsequent research, diagnostic applications and the development of specific treatments. The present article reviews the available scientific publications dealing with the composition and function of the sperm cell using an MS proteomic approach.

  18. Cryopreservation of Fish Sperm

    Science.gov (United States)

    Kurokura, Hisashi

    Present status of research activities in cryopreservation of fish gamete in aquaculture field was introduced. More than 59 fish species have been reported in the research histories and nearly half of them were studied during recent 10 years. This means that the research activities are increasing, though commercial profit have not obtained yet. Fish species of which sperm can successfully cryopreserved is still limited comparing to numerous species in telost. One of the major obstacle for improvement of the technique is existence of wide specie specific variance in the freezing tolerance of fish sperm. The varianc can possibly be explaind thorugh the informations obtained by the studies in comparative spermatology, which is recently activated field in fish biology.

  19. Morphology, Structure of Dimorphic Sperm, and Reproduction in the Hermaphroditic Commensal Bivalve Pseudopythina tsurumaru (Galeommatoidea: Kellidae)

    DEFF Research Database (Denmark)

    Lützen, Jørgen; Jespersen, Åse; Takahashi, Tohru

    2004-01-01

    Galeommatoide, commensal bivalve, reproduction, dimorphic sperm, sperm ultrastructure, spermatozeugma......Galeommatoide, commensal bivalve, reproduction, dimorphic sperm, sperm ultrastructure, spermatozeugma...

  20. Sperm function test

    Directory of Open Access Journals (Sweden)

    Pankaj Talwar

    2015-01-01

    Full Text Available With absolute normal semen analysis parameters it may not be necessary to shift to specialized tests early but in cases with borderline parameters or with history of fertilization failure in past it becomes necessary to do a battery of tests to evaluate different parameters of spermatozoa. Various sperm function tests are proposed and endorsed by different researchers in addition to the routine evaluation of fertility. These tests detect function of a certain part of spermatozoon and give insight on the events in fertilization of the oocyte. The sperms need to get nutrition from the seminal plasma in the form of fructose and citrate (this can be assessed by fructose qualitative and quantitative estimation, citrate estimation. They should be protected from the bad effects of pus cells and reactive oxygen species (ROS (leukocyte detection test, ROS estimation. Their number should be in sufficient in terms of (count, structure normal to be able to fertilize eggs (semen morphology. Sperms should have intact and functioning membrane to survive harsh environment of vagina and uterine fluids (vitality and hypo-osmotic swelling test, should have good mitochondrial function to be able to provide energy (mitochondrial activity index test. They should also have satisfactory acrosome function to be able to burrow a hole in zona pellucida (acrosome intactness test, zona penetration test. Finally, they should have properly packed DNA in the nucleus to be able to transfer the male genes (nuclear chromatic decondensation test to the oocyte during fertilization.

  1. Ovarian fluid impacts flagellar beating and biomechanical metrics of sperm between alternative reproductive tactics

    Czech Academy of Sciences Publication Activity Database

    Butts, I. A. E.; Prokopchuk, Galina; Kašpar, V.; Cosson, J.; Pitcher, T. E.

    2017-01-01

    Roč. 220, č. 12 (2017), s. 2210-2217 ISSN 0022-0949 Institutional support: RVO:60077344 Keywords : competition * salmon * Oncorhynchus tshawytscha * spawning * reproductive strategy * sperm competition * cryptic female choice Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 3.320, year: 2016

  2. Application of surface enhanced Raman scattering and competitive adaptive reweighted sampling on detecting furfural dissolved in transformer oil

    Science.gov (United States)

    Chen, Weigen; Zou, Jingxin; Wan, Fu; Fan, Zhou; Yang, Dingkun

    2018-03-01

    Detecting the dissolving furfural in mineral oil is an essential technical method to evaluate the ageing condition of oil-paper insulation and the degradation of mechanical properties. Compared with the traditional detection method, Raman spectroscopy is obviously convenient and timesaving in operation. This study explored the method of applying surface enhanced Raman scattering (SERS) on quantitative analysis of the furfural dissolved in oil. Oil solution with different concentration of furfural were prepared and calibrated by high-performance liquid chromatography. Confocal laser Raman spectroscopy (CLRS) and SERS technology were employed to acquire Raman spectral data. Monte Carlo cross validation (MCCV) was used to eliminate the outliers in sample set, then competitive adaptive reweighted sampling (CARS) was developed to select an optimal combination of informative variables that most reflect the chemical properties of concern. Based on selected Raman spectral features, support vector machine (SVM) combined with particle swarm algorithm (PSO) was used to set up a furfural quantitative analysis model. Finally, the generalization ability and prediction precision of the established method were verified by the samples made in lab. In summary, a new spectral method is proposed to quickly detect furfural in oil, which lays a foundation for evaluating the ageing of oil-paper insulation in oil immersed electrical equipment.

  3. New Hybrid Multiple Attribute Decision-Making Model for Improving Competence Sets: Enhancing a Company’s Core Competitiveness

    Directory of Open Access Journals (Sweden)

    Kuan-Wei Huang

    2016-02-01

    Full Text Available A company’s core competitiveness depends on the strategic allocation of its human resources in alignment with employee capabilities. Competency models can identify the range of capabilities at a company’s disposal, and this information can be used to develop internal or external education training policies for sustainable development. Such models can ensure the importation of a strategic orientation reflecting the growth of its employee competence set and enhancing human resource sustainably. This approach ensures that the most appropriate people are assigned to the most appropriate positions. In this study, we proposed a new hybrid multiple attributed decision-making model by using the Decision-making trial and Evaluation Laboratory Technique (DEMATEL to construct an influential network relation map (INRM and determined the influential weights by using the basic concept of the analytic network process (called DEMATEL-based ANP, DANP; the influential weights were then adopted with a modified Vise Kriterijumska Optimizacija I Kompromisno Resenje (VIKOR method. A simple forecasting technique as an iteration function was also proposed. The proposed model was effective. We expect that the proposed model can facilitate making timely revisions, reflecting the growth of employee competence sets, reducing the performance gap toward the aspiration level, and ensuring the sustainability of a company.

  4. Cryopreservation of microencapsulated canine sperm.

    Science.gov (United States)

    Shah, Shambhu; Otsuki, Tsubasa; Fujimura, Chika; Yamamoto, Naoki; Yamashita, Yasuhisa; Higaki, Shogo; Hishinuma, Mitsugu

    2011-03-01

    The objective was to develop a method for cryopreserving microencapsulated canine sperm. Pooled ejaculates from three beagle dogs were extended in egg yolk tris extender and encapsulated using alginate and poly-L-lysine at room temperature. The microcapsules were cooled at 4 °C, immersed in pre-cooled extender (equivalent in volume to the microcapsules) to reach final concentration of 7% (v/v) glycerol and 0.75% (v/v) Equex STM paste, and equilibrated for 5, 30 and 60 min at 4 °C. Thereafter, microcapsules were loaded into 0.5 mL plastic straws and frozen in liquid nitrogen. In Experiment 1, characteristics of microencapsulated canine sperm were evaluated after glycerol addition at 4 °C. Glycerol exposure for 5, 30 and 60 min did not significantly affect progressive motility, viability, or acrosomal integrity of microencapsulated sperm compared with pre-cooled unencapsulated sperm (control). In Experiment 2, characteristics of frozen-thawed canine microencapsulated sperm were evaluated at 0, 3, 6, and 9 h of culture at 38.5 °C. Pre-freeze glycerol exposure for 5, 30, and 60 min at 4 °C did not influence post-thaw quality in unencapsulated sperm. Post-thaw motility and acrosomal integrity of microencapsulated sperm decreased more than those of unencapsulated sperm (P < 0.05) following glycerol exposure for 5 min. However, motility, viability and acrosomal integrity of microencapsulated sperm after 30 and 60 min glycerol exposure were higher than unencapsulated sperm cultured for 6 or 9 h (P < 0.05). In conclusion, since microencapsulated canine sperm were successfully cryopreserved, this could be a viable alternative to convention sperm cryopreservation in this species. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. First production of larvae using cryopreserved sperm: Effects of preservation temperature and cryopreservation on European eel sperm fertilization capacity

    DEFF Research Database (Denmark)

    Asturiano, J.F.; Sørensen, Sune Riis; Perez, L.

    2016-01-01

    have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization....... Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few...... larvae ('cryolarvae') were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success...

  6. Cryopreservation of epididymal stallion sperm.

    Science.gov (United States)

    Olaciregui, M; Gil, L; Montón, A; Luño, V; Jerez, R A; Martí, J I

    2014-02-01

    Any event that makes semen collection or mating impossible, such as death, castration, or injury, may terminate a stallion's breeding career. Fortunately, stallion sperm which are capable of fertilization can be harvested from the epididymis, and frozen for future use. However, the fertility of frozen-thawed epididymal sperm has been found to be lower than that of ejaculated sperm. Therefore, this study aimed to optimize the fertility of frozen epididymal stallion sperm by investigating the effects of different cryoprotectants and freezing protocols on sperm quality. Dimethylformamide was tested alone or combination with pasteurized egg yolk as substitute of fresh egg yolk. In addition, the effect of the pre-freeze stabilization on sperm quality was analyzed. Heterospermic samples obtained from stallion epididymis were collected and cryopreserved in lactose-egg-yolk extender or in the same extender with varying content of cryoprotectant and content of egg yolk, stabilized and no-stabilized. Sperm motility, viability, hypoosmotic swelling test (HOST) and acrosome integrity were evaluated post-thawing. No improvement was observed on the replacement of fresh yolk by pasteurized egg yolk, whereas the results suggest that dimethylformamide is a cryoprotectant suitable for cryopreservation of equine epididymal semen, even better than glycerol. In addition, we found that the stabilization before freezing on epididymal stallion sperm, can improve sperm quality parameters. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Female mediation of competitive fertilization success in Drosophila melanogaster.

    Science.gov (United States)

    Lüpold, Stefan; Pitnick, Scott; Berben, Kirstin S; Blengini, Cecilia S; Belote, John M; Manier, Mollie K

    2013-06-25

    How females store and use sperm after remating can generate postcopulatory sexual selection on male ejaculate traits. Variation in ejaculate performance traits generally is thought to be intrinsic to males but is likely to interact with the environment in which sperm compete (e.g., the female reproductive tract). Our understanding of female contributions to competitive fertilization success is limited, however, in part because of the challenges involved in observing events within the reproductive tract of internally fertilizing species while discriminating among sperm from competing males. Here, we used females from crosses among isogenic lines of Drosophila melanogaster, each mated to two genetically standardized males (the first with green- and the second with red-tagged sperm heads) to demonstrate heritable variation in female remating interval, progeny production rate, sperm-storage organ morphology, and a number of sperm performance, storage, and handling traits. We then used multivariate analyses to examine relationships between this female-mediated variation and competitive paternity. In particular, the timing of female ejection of excess second-male and displaced first-male sperm was genetically variable and, by terminating the process of sperm displacement, significantly influenced the relative numbers of sperm from each male competing for fertilization, and consequently biased paternity. Our results demonstrate that females do not simply provide a static arena for sperm competition but rather play an active and pivotal role in postcopulatory processes. Resolving the adaptive significance of genetic variation in female-mediated mechanisms of sperm handling is critical for understanding sexual selection, sexual conflict, and the coevolution of male and female reproductive traits.

  8. Daily Sperm Production, Gonadal and Extra-Gonadal Sperm ...

    African Journals Online (AJOL)

    SH

    significantly (P<0.05) higher in rabbits fed prebiotic and symbiotic diets than those fed diet 3 and the control. The daily sperm production and sperm ... The amount of good quality live spermatozoa produced by the testis and the ... production and reproductive performance of rabbits. Effects of nutrition on reproduction.

  9. Factors influencing boar sperm cryosurvival.

    Science.gov (United States)

    Roca, J; Hernández, M; Carvajal, G; Vázquez, J M; Martínez, E A

    2006-10-01

    Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that

  10. Hyaluronic acid binding ability of human sperm reflects cellular maturity and fertilizing potential: selection of sperm for intracytoplasmic sperm injection.

    Science.gov (United States)

    Huszar, Gabor; Ozkavukcu, Sinan; Jakab, Attila; Celik-Ozenci, Ciler; Sati, G Leyla; Cayli, Sevil

    2006-06-01

    The current concepts of sperm biochemical markers and the central role of the HspA2 chaperone protein, a measure of sperm cellular maturity and fertilizing potential, are reviewed. Because HspA2 is a component of the synaptonemal complex, low HspA2 levels and increased frequency of chromosomal aneuploidies are related in diminished maturity sperm. We also suggest a relationship between HspA2 expression in elongating spermatids and events of late spermiogenesis, such as cytoplasmic extrusion and plasma membrane remodeling that aid the formation of the zona pellucida binding and hyaluronic acid binding sites. The presence of hyaluronic acid receptor on the plasma membrane of mature sperm, coupled with hyaluronic acid coated glass or plastic surfaces, facilitates testing of sperm function and selection of single mature sperm for intracytoplasmic sperm injection. The frequencies of sperm with chromosomal disomy are reduced approximately fourfold to fivefold in hyaluronic acid selected sperm compared with semen sperm, comparable to the increase in such abnormalities in intracytoplasmic sperm injection offspring. Hyaluronic acid binding also excludes immature sperm with cytoplasmic extrusion, persistent histones, and DNA chain breaks. Hyaluronic acid mediated sperm selection is a novel technique that is comparable to sperm zona pellucida binding. Hyaluronic acid selected sperm will also alleviate the risks related to intracytoplasmic sperm injection fertilization with sperm of diminished maturity that currently cause worldwide concern.

  11. “Just what the doctor ordered”: Factors associated with oncology patients’ decision to bank sperm

    Science.gov (United States)

    Yee, Samantha; Fuller-Thomson, Esme; Dwyer, Catherine; Greenblatt, Ellen; Shapiro, Heather

    2012-01-01

    Introduction: The purpose of this cross-sectional study was to explore factors associated with oncology patients’ decision to bank sperm prior to cancer treatment. Materials and Methods: Patients who were referred to the oncology sperm banking program between January 2009 and March 2010 were invited to complete an 18-item questionnaire during one of their sperm banking visits. Results: Of the 157 cancer patients referred to the Mount Sinai Oncology Sperm and Tissue Bank for sperm banking during the 15-month period, 79 questionnaires were returned (50% response rate). Of the respondents, 89% were informed about sperm banking by their physician. Future family planning was cited as the main reason to bank. Cost was not a barrier for the vast majority of respondents. Forty percent of respondents banked sperm within 4 days prior to initiating cancer treatment. Most respondents relied on their physician for verbal information on sperm banking. Eighty-one percent were unaware of any patient organizations that have educational materials on oncology fertility preservation. Conclusion: Sperm banking prior to cancer treatment is the only proven method of preserving fertility for cancer patients. The two main determinants associated with deciding whether to bank sperm were: the physician’s recommendation and the patient’s desire for future fatherhood. Physicians play a key role in influencing patients’ decisions. The recommendation to bank sperm is a persuasive message if patients are clearly informed about their potential risk of infertility post-cancer treatment, and that sperm banking is an effective way of preserving fertility. Providing patients with education materials might enhance compliance in sperm banking. PMID:21539768

  12. Sperm length variation as a predictor of extrapair paternity in passerine birds

    OpenAIRE

    Lifjeld, J. T.; Laskemoen, T.; Kleven, O.; Albrecht, T. (Tomáš); Robertson, R. J.

    2010-01-01

    BACKGROUND: The rate of extrapair paternity is a commonly used index for the risk of sperm competition in birds, but paternity data exist for only a few percent of the approximately 10400 extant species. As paternity analyses require extensive field sampling and costly lab work, species coverage in this field will probably not improve much in the foreseeable future. Recent findings from passerine birds, which constitute the largest avian order (∼5,900 species), suggest that sperm phenotypes c...

  13. Methods of sperm vitality assessment.

    Science.gov (United States)

    Moskovtsev, Sergey I; Librach, Clifford L

    2013-01-01

    Sperm vitality is a reflection of the proportion of live, membrane-intact spermatozoa determined by either dye exclusion or osmoregulatory capacity under hypo-osmotic conditions. In this chapter we address the two most common methods of sperm vitality assessment: eosin-nigrosin staining and the hypo-osmotic swelling test, both utilized in clinical Andrology laboratories.

  14. Social imaginaries, sperm and whiteness

    DEFF Research Database (Denmark)

    Andreassen, Rikke

    2017-01-01

    This article analyses narratives about so-called Viking babies and Viking sperm. Over the last few years an increasing number of British single women and lesbian couples have been creating families by becoming pregnant with Danish donor sperm, termed ‘Viking sperm’. Through analyses of British...

  15. Sperm preparation for ART

    Directory of Open Access Journals (Sweden)

    Schill Wolf-Bernhard

    2003-11-01

    Full Text Available Abstract The onset of clinical assisted reproduction, a quarter of a century ago, required the isolation of motile spermatozoa. As the indication of assisted reproduction shifted from mere gynaecological indications to andrological indications during the years, this urged andrological research to understand the physiology of male germ cell better and develop more sophisticated techniques to separate functional spermatozoa from those that are immotile, have poor morphology or are not capable to fertilize oocytes. Initially, starting from simple washing of spermatozoa, separation techniques, based on different principles like migration, filtration or density gradient centrifugation evolved. The most simple and cheapest is the conventional swim-up procedure. A more sophisticated and most gentle migration method is migration-sedimentation. However, its yield is relatively small and the technique is therefore normally only limited to ejaculates with a high number of motile spermatozoa. Recently, however, the method was also successfully used to isolate spermatozoa for intracytoplasmic sperm injection (ICSI. Sperm separation methods that yield a higher number of motile spermatozoa are glass wool filtration or density gradient centrifugation with different media. Since Percoll® as a density medium was removed from the market in 1996 for clinical use in the human because of its risk of contamination with endotoxins, other media like IxaPrep®, Nycodenz, SilSelect®, PureSperm® or Isolate® were developed in order to replace Percoll®. Today, an array of different methods is available and the selection depends on the quality of the ejaculates, which also includes production of reactive oxygen species (ROS by spermatozoa and leukocytes. Ejaculates with ROS production should not be separated by means of conventional swim-up, as this can severely damage the spermatozoa. In order to protect the male germ cells from the influence of ROS and to stimulate

  16. Experience of mating rivals causes males to modulate sperm transfer in the fly Drosophila pseudoobscura.

    Science.gov (United States)

    Price, Tom A R; Lizé, Anne; Marcello, Marco; Bretman, Amanda

    2012-12-01

    Male responses to risk of sperm competition play an important role in sexual selection, sexual conflict, and the evolution of mating systems. Such responses can combine behavioural and physiological processes, and can be mediated through different components of the ejaculate such as sperm numbers and seminal proteins. An additional level of ejaculate complexity is sperm heteromorphism, with the inclusion of non-fertilising parasperm in the ejaculate. We now test the response to rivals in a sperm heteromorphic species, Drosophila pseudoobscura, measuring the behavioural response and sperm transfer and, crucially, relating these to short-term fitness. Males respond to exposure to conspecific rivals by increasing mating duration, but do not respond to heterospecific rivals. In addition, after exposure to a conspecific rival, males increased the transfer of fertilising eusperm, but not non-fertilising parasperm. Males exposed to a conspecific rival also achieve higher offspring production. This suggests that the evolution of parasperm in flies was not driven by sperm competition and adds to the increasing evidence that males can make extremely sophisticated responses to mating competition. Copyright © 2012. Published by Elsevier Ltd.

  17. No evidence of inbreeding depression in sperm performance traits in wild song sparrows.

    Science.gov (United States)

    Losdat, Sylvain; Germain, Ryan R; Nietlisbach, Pirmin; Arcese, Peter; Reid, Jane M

    2018-02-01

    Inbreeding is widely hypothesized to shape mating systems and population persistence, but such effects will depend on which traits show inbreeding depression. Population and evolutionary consequences could be substantial if inbreeding decreases sperm performance and hence decreases male fertilization success and female fertility. However, the magnitude of inbreeding depression in sperm performance traits has rarely been estimated in wild populations experiencing natural variation in inbreeding. Further, the hypothesis that inbreeding could increase within-ejaculate variation in sperm traits and thereby further affect male fertilization success has not been explicitly tested. We used a wild pedigreed song sparrow ( Melospiza melodia ) population, where frequent extrapair copulations likely create strong postcopulatory competition for fertilization success, to quantify effects of male coefficient of inbreeding ( f ) on key sperm performance traits. We found no evidence of inbreeding depression in sperm motility, longevity, or velocity, and the within-ejaculate variance in sperm velocity did not increase with male f . Contrary to inferences from highly inbred captive and experimental populations, our results imply that moderate inbreeding will not necessarily constrain sperm performance in wild populations. Consequently, the widely observed individual-level and population-level inbreeding depression in male and female fitness may not stem from reduced sperm performance in inbred males.

  18. Spermicide, cryptic female choice and the evolution of sperm form and function.

    Science.gov (United States)

    Holman, L; Snook, R R

    2006-09-01

    Sperm competition and cryptic female choice profoundly affect sperm morphology, producing diversity within both species and individuals. One type of within-individual sperm variation is sperm heteromorphism, in which each male produces two or more distinct types of sperm simultaneously, only one of which is typically fertile (the "eusperm"). The adaptive significance of nonfertile "parasperm" types is poorly understood, although numerous sperm-heteromorphic species are known from many disparate taxa. This paper examines in detail two female-centred hypotheses for the evolution and maintenance of this unconventional sperm production strategy. First, we use game theoretical models to establish that parasperm may function to protect eusperm from female-generated spermicide, and to elucidate the predictions of this idea. Second, we expand on the relatively undeveloped idea that parasperm are used by females as a criterion for cryptic female choice, and discuss the predictions generated by this idea compared to other hypotheses proposed to explain sperm heteromorphism. We critically evaluate both hypotheses, suggest ways in which they could be tested, and propose taxa in which they could be important.

  19. Male contest competition and the coevolutionof weaponry and testes in pinnipeds

    OpenAIRE

    Fitzpatrick, J.L.; Almbro, M.; González-Voyer, Alejandro; Kolm, N.; Simmons, Leigh W.

    2012-01-01

    Male reproductive success is influenced by competitive interactions during precopulatory and postcopulatory selective episodes. Consequently, males can gain reproductive advantages during precopulatory contest competition by investing in weaponry and during postcopulatory sperm competition by investing in ejaculates. However, recent theory predicts male expenditure on weaponry and ejaculates should be subject to a trade-off, and should vary under increasing risk and intensity of sperm competi...

  20. Relationship between sperm parameters and intracytoplasmic sperm injection outcome

    Directory of Open Access Journals (Sweden)

    Shahla Chaichian

    2015-12-01

    Full Text Available Objectives: With the adventure of intracytoplasmic sperm injection (ICSI technique, great progresses have developed in the treatment of infertility. Concentration on the properties of male’s gamete has been encouraged by the increasing concerns about the causes of ICSI failure. We hence conducted this study to investigate the probable association of sperm parameters with ISCI outcome. Methods: A total of 523 couples referred to Isfahan Fertility and Sterility Center from January 2007 to June 2008 for ICSI. Semen analysis was performed before ICSI procedure according to the WHO criteria. Patients were assigned into successful ICSI (case and failed ICSI (control groups. Sperm parameters were then compared between the 2 groups. Results: One hundred and six patients (20% had successful ICSI results (case group compared with 417 couples (80% with undesirable ICSI outcomes (control group. Among evaluated factors, sperm agglutination (p = 0.007, sperm concentration (p = 0.043, leukocytospermia (p = 0.026 and head abnormality of sperm (p = 0.019 showed statistically significant differences between two groups with differing ICSI results. None of the other semen parameters revealed significant differences between these two groups. Conclusion: Our study showed that some sperm parameters are associated with desirable ICSI outcome. However, it is unclear whether these associations are causal.

  1. Orientation of sea urchin sperms in static magnetic fields: Compared to human sperms

    Science.gov (United States)

    Sakhnini, Lama; Dairi, Maheen

    In this study we report on magnetic orientation of sea urchin and human sperms. The sea urchin and human sperms became oriented parallel to the magnetic field (1 T maximum). The human sperms were totally oriented with magnetic field at about 600 mT. However, the sea urchin sperms show different behavior due to morphological differences between them and the human sperms.

  2. Sexing mammalian sperm for production of offspring: the state-of-the-art.

    Science.gov (United States)

    Johnson, L A

    2000-07-02

    numbers in the pig would be advantageous to the utilization of sexed sperm for some type of deep artificial insemination. Such a development would also enhance the economy of using lower sperm numbers with conventional artificial insemination (AI) and aid the swine industry worldwide. The use of sexed sperm for non-ordinary applications such as endangered species, laboratory animals, hobby or pet species is also of interest and will become a part of the move to be more reproductively efficient in the next millennium. Sexed sperm on demand over the next several years will provide livestock producers with many options in seeking to improve efficiency of production and improve quality of products to enhance consumer acceptability.

  3. Sperm length variation as a predictor of extrapair paternity in passerine birds.

    Directory of Open Access Journals (Sweden)

    Jan T Lifjeld

    2010-10-01

    Full Text Available The rate of extrapair paternity is a commonly used index for the risk of sperm competition in birds, but paternity data exist for only a few percent of the approximately 10400 extant species. As paternity analyses require extensive field sampling and costly lab work, species coverage in this field will probably not improve much in the foreseeable future. Recent findings from passerine birds, which constitute the largest avian order (∼5,900 species, suggest that sperm phenotypes carry a signature of sperm competition. Here we examine how well standardized measures of sperm length variation can predict the rate of extrapair paternity in passerine birds.We collected sperm samples from 55 passerine species in Canada and Europe for which extrapair paternity rates were already available from either the same (n = 24 or a different (n = 31 study population. We measured the total length of individual spermatozoa and found that both the coefficient of between-male variation (CV(bm and within-male variation (CV(wm in sperm length were strong predictors of the rate of extrapair paternity, explaining as much as 65% and 58%, respectively, of the variation in extrapair paternity among species. However, only the CV(bm predictor was independent of phylogeny, which implies that it can readily be converted into a currency of extrapair paternity without the need for phylogenetic correction.We propose the CV(bm index as an alternative measure to extrapair paternity for passerine birds. Given the ease of sperm extraction from male birds in breeding condition, and a modest number of sampled males required for a robust estimate, this new index holds a great potential for mapping the risk of sperm competition across a wide range of passerine birds.

  4. Sperm length variation as a predictor of extrapair paternity in passerine birds.

    Science.gov (United States)

    Lifjeld, Jan T; Laskemoen, Terje; Kleven, Oddmund; Albrecht, Tomas; Robertson, Raleigh J

    2010-10-18

    The rate of extrapair paternity is a commonly used index for the risk of sperm competition in birds, but paternity data exist for only a few percent of the approximately 10400 extant species. As paternity analyses require extensive field sampling and costly lab work, species coverage in this field will probably not improve much in the foreseeable future. Recent findings from passerine birds, which constitute the largest avian order (∼5,900 species), suggest that sperm phenotypes carry a signature of sperm competition. Here we examine how well standardized measures of sperm length variation can predict the rate of extrapair paternity in passerine birds. We collected sperm samples from 55 passerine species in Canada and Europe for which extrapair paternity rates were already available from either the same (n = 24) or a different (n = 31) study population. We measured the total length of individual spermatozoa and found that both the coefficient of between-male variation (CV(bm)) and within-male variation (CV(wm)) in sperm length were strong predictors of the rate of extrapair paternity, explaining as much as 65% and 58%, respectively, of the variation in extrapair paternity among species. However, only the CV(bm) predictor was independent of phylogeny, which implies that it can readily be converted into a currency of extrapair paternity without the need for phylogenetic correction. We propose the CV(bm) index as an alternative measure to extrapair paternity for passerine birds. Given the ease of sperm extraction from male birds in breeding condition, and a modest number of sampled males required for a robust estimate, this new index holds a great potential for mapping the risk of sperm competition across a wide range of passerine birds.

  5. Colloid single-layer centrifugation improves post-thaw donkey (Equus asinus) sperm quality and is related to ejaculate freezability.

    Science.gov (United States)

    Ortiz, I; Dorado, J; Acha, D; Gálvez, M J; Urbano, M; Hidalgo, M

    2015-01-01

    The aim of this study was to determine whether colloid single-layer centrifugation (SLC) improves post-thaw donkey sperm quality and if this potential enhancement is related to ejaculate freezability. Semen from Andalusian donkeys was frozen following a standard protocol. SLC was performed on frozen-thawed semen and post-thaw sperm parameters were compared with uncentrifuged samples. Sperm quality was estimated by integrating in a single value sperm motility (assessed by computer-assisted sperm analysis), morphology and viability (evaluated under brightfield or fluorescence microscopy). Sperm freezability was calculated as the relationship between sperm quality obtained before freezing and after thawing. Ejaculates were classified into low, medium and high freezability groups using the 25th and 75th percentiles as thresholds. All sperm parameters were significantly (P<0.01) higher in SLC-selected samples in comparison to uncentrifuged frozen-thawed semen and several kinematic parameters were even higher than those obtained in fresh semen. The increment of sperm parameters after SLC selection was correlated with ejaculate freezability, obtaining the highest values after SLC in semen samples with low freezability. We concluded that, based on the sperm-quality parameters evaluated, SLC can be a suitable procedure to improve post-thaw sperm quality of cryopreserved donkey semen, in particular for those ejaculates with low freezability.

  6. COMPETITIVENESS THROUGH INFORMATION

    Directory of Open Access Journals (Sweden)

    Raluca Daniela RIZEA

    2013-10-01

    Full Text Available Intelligence competitiveness has already started to build its road in the company’s long term strategies. Nonetheless, business executives continue to look for ways to apply information technology strategically to their businesses. Using information managers manage to communicate, to convey their knowledge about markets, competitors, products, services and operations. Even if data and information are all over there are few amounts of managers that realize the importance of them to the success of the business. This article will review competitive forces and competitive information systems strategies for gaining competitive advantages, explain concepts of value chain, value co-opetition (competition and cooperation, and discuss innovation strategy. Co-opetition is a strategy whereby companies cooperate and compete at the same time with their competitors, complementors (i.e. hardware and software businesses, customers, suppliers. The article discuss an important dimension of information system, identifies competitive advantages and enhancing competitive strategies thought information systems.

  7. Sperm structure and sperm transfer in Pseudopythina subsinuata (Bivalvia, Galeommatoidea)

    DEFF Research Database (Denmark)

    Jespersen, Åse

    2009-01-01

    to the elongate cells. Most females contain one to three "sperm trees", structures consisting of a short stem and numerous branches. They are firmly implanted in the abfrontal part of the gill filament and protrude into the posterior part of the suprabranchial (brooding) chamber. Implantation of the trees causes...... the receptacle and thereupon fuse. A similar process is known in the allied P. tsurumaru, but the resulting structure ("sperm-carrying body") is not attached to the gills....

  8. Myoinositol: does it improve sperm mitochondrial function and sperm motility?

    Science.gov (United States)

    Condorelli, Rosita A; La Vignera, Sandro; Bellanca, Salvatore; Vicari, Enzo; Calogero, Aldo E

    2012-06-01

    To evaluate whether an improvement in mitochondrial membrane potential was associated with sperm motility amelioration and greater sperm recovery after the swim-up procedure. A second purpose was to evaluate the effects of myoinositol (MYO) on sperm apoptosis, quality of chromatin compaction, and DNA integrity. Spermatozoa from 20 normozoospermic men and 20 patients with oligo-astheno-teratozoospermia were incubated in vitro with 2 mg/mL of MYO or phosphate-buffered saline as a control for 2 hours. After this incubation period, sperm motility was evaluated. Flow cytometry was used to analyze the mitochondrial membrane potential, phosphatidylserine externalization, chromatin compactness, and DNA fragmentation. We also evaluated the total number of motile spermatozoa recovered after swim-up after incubation with MYO or phosphate-buffered saline. MYO significantly increased the percentage of spermatozoa with progressive motility in both normozoospermic men and patients with oligo-astheno-teratozoospermia. Motility improvement in the latter group was associated with a significant increase in the percentage of spermatozoa with high mitochondrial membrane potential. MYO had no effects on mitochondrial function in spermatozoa from normozoospermic men. Sperm phosphatidylserine externalization, chromatin compactness, and DNA fragmentation were unaffected by MYO in both groups. After incubation with MYO, the total number of spermatozoa recovered after swim-up had improved significantly in both groups. These data show that MYO increases sperm motility and the number of spermatozoa retrieved after swim-up in both normozoospermic men and patients with abnormal sperm parameters. In patients with oligo-astheno-teratozoospermia, the improvement in these parameters was associated with improved sperm mitochondrial function. These findings support the use of MYO in both in vivo- and in vitro-assisted reproductive techniques. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Sperm Proteome Maturation in the Mouse Epididymis.

    Science.gov (United States)

    Skerget, Sheri; Rosenow, Matthew A; Petritis, Konstantinos; Karr, Timothy L

    2015-01-01

    In mammals, transit through the epididymis, which involves the acquisition, loss and modification of proteins, is required to confer motility and fertilization competency to sperm. The overall dynamics of maturation is poorly understood, and a systems level understanding of the complex maturation process will provide valuable new information about changes occurring during epididymal transport. We report the proteomes of sperm collected from the caput, corpus and cauda segments of the mouse epididymis, identifying 1536, 1720 and 1234 proteins respectively. This study identified 765 proteins that are present in sperm obtained from all three segments. We identified 1766 proteins that are potentially added (732) or removed (1034) from sperm during epididymal transit. Phenotypic analyses of the caput, corpus and cauda sperm proteomes identified 60 proteins that have known sperm phenotypes when mutated, or absent from sperm. Our analysis indicates that as much as one-third of proteins with known sperm phenotypes are added to sperm during epididymal transit. GO analyses revealed that cauda sperm are enriched for specific functions including sperm-egg recognition and motility, consistent with the observation that sperm acquire motility and fertilization competency during transit through the epididymis. In addition, GO analyses revealed that the immunity protein profile of sperm changes during sperm maturation. Finally, we identified components of the 26S proteasome, the immunoproteasome, and a proteasome activator in mature sperm.

  10. Female gamete competition in an ancient angiosperm lineage.

    Science.gov (United States)

    Bachelier, Julien B; Friedman, William E

    2011-07-26

    In Trimenia moorei, an extant member of the ancient angiosperm clade Austrobaileyales, we found a remarkable pattern of female gametophyte (egg-producing structure) development that strikingly resembles that of pollen tubes and their intrasexual competition within the maternal pollen tube transmitting tissues of most flowers. In contrast with most other flowering plants, in Trimenia, multiple female gametophytes are initiated at the base (chalazal end) of each ovule. Female gametophytes grow from their tips and compete over hundreds of micrometers to reach the apex of the nucellus and the site of fertilization. Here, the successful female gametophyte will mate with a pollen tube to produce an embryo and an endosperm. Moreover, the central tissue within the ovules of Trimenia, through which the embryo sacs grow, contains starch and other carbohydrates similar to the pollen tube transmitting tissues in the styles of most flowers. The pattern of female gametophyte development found in Trimenia is rare but by no means unique in angiosperms. Importantly, it seems that multiple female gametophytes are occasionally or frequently initiated in members of other ancient angiosperm lineages. The intensification of pollen tube (male gametophyte) competition and enhanced maternal selection among competing pollen tubes are considered to have been major contributors to the rise of angiosperms. Based on insights from Trimenia, we posit that prefertilization female gametophyte (egg) competition within individual ovules in addition to male gametophyte (sperm) competition and maternal mate choice may have been key features of the earliest angiosperms.

  11. Sperm fractions obtained following density gradient centrifugation in human ejaculates show differences in sperm DNA longevity

    Directory of Open Access Journals (Sweden)

    Jaime Gosálvez

    2014-06-01

    Conclusion: 1 Unnecessary incubation of spermatozoa prior to artificial insemination or in vitro fertilization, should be avoided, since sperm DNA longevity is significantly reduced after ex vivo sperm handling and 2 Although sperm selection by DCG significantly reduces the baseline levels of SDF of sperm in Fraction 3, sperm DNA longevity in this fraction was ultimately lower following 24 h incubation when compared to sperm recovered from non-centrifuged NSS.

  12. Photosynthetic response, survival, and growth of three ponderosa pine stocktypes under water stress enhanced by vegetative competition

    Science.gov (United States)

    Jeremiah R. Pinto; John D. Marshall; R. Kasten Dumroese; Anthony S. Davis; Douglas R. Cobos

    2012-01-01

    Selecting the proper stock type for reforestation on dry sites can be critical for the long-term survival and growth of seedlings. In this study, we use a novel approach to understand stock type selection on a site where drought was induced with vegetative competition. Three ponderosa pine (Pinus ponderosa Lawson & C. Lawson var. ponderosa C. Lawson) seedling stock...

  13. Copulatory behavior in a pholcid spider: males use specialized genitalic movements for sperm removal and copulatory courtship

    Science.gov (United States)

    Calbacho-Rosa, Lucía; Galicia-Mendoza, Ivette; Dutto, María Sofía; Córdoba-Aguilar, Alex; Peretti, Alfredo V.

    2013-05-01

    Sexual selection may operate on pre-copulatory, copulatory, and post-copulatory traits. An example of a copulatory target of sexual selection is the genitalic movements a male performs during copulation. These movements may function either to prevent sperm competition or to influence a female's fertilization decision. Here we investigated how copulation duration, pedipalp movements, and abdominal movements that males of the pholcid spider Holocnemus pluchei produce during copulation influence sperm removal and/or patterns of successful sperm transfer. We compared mating events with virgin and mated females for differences in copulatory and post-copulatory behavior. We expected longer copulation duration, longer pedipalp movement duration, and more complex and frequent pedipalp and abdominal movements when males mated with mated females compared to virgin females. Except for abdominal movements, our results corroborated these predictions. Furthermore, when we investigated mating events with mated females, we observed sperm mass ejection from the female gonopore and physical removal of sperm by males' procursi. Females with interrupted second mating events showed a significant reduction of stored sperm masses compared to females with completed mating events. We suggest that males use alternating pedipalp movements to remove most of the rival sperm stored by mated females prior to sperm transfer. Copulation duration and pedipalp movements can be further used to transfer sperm and/or as a form of genitalic copulatory courtship.

  14. Energy Utilization for Survival and Fertilization-Parsimonious Quiescent Sperm Turn Extravagant on Motility Activation in Rat.

    Science.gov (United States)

    Kumar, Lokesh; Yadav, Santosh K; Kushwaha, Bhavana; Pandey, Aastha; Sharma, Vikas; Verma, Vikas; Maikhuri, Jagdamba P; Rajender, Singh; Sharma, Vishnu L; Gupta, Gopal

    2016-04-01

    Quiescent sperm survive in cauda epididymis for long periods of time under extreme crowding conditions and with a very limited energy substrate, while after ejaculation, motile sperm live for a much shorter period with an unlimited energy resource and without crowding. Thus, the energy metabolism in relation to the energy requirement of the two may be quite different. A simple physiological technique was evolved to collect viable quiescent sperm from rat cauda epididymis to compare its energy metabolism with motile sperm. Quiescent sperm exhibited 40%-60% higher activities of mitochondrial electron transport chain complexes I-IV and ATP synthase in comparison to motile sperm and accumulated Ca(2+) in the midpiece mitochondria to enhance oxidative phosphorylation (OxPhos). In contrast, motile sperm displayed up to 75% higher activities of key glycolytic enzymes and secreted more than two times the lactate than quiescent sperm. Quiescent sperm phosphorylated AMPK and MAPK-p38, while motile sperm phosphorylated AKT and MAPK/ERK. Glycolytic inhibitor iodoacetamide prevented motility activation of quiescent rat sperm and inhibited conception in rabbits more effectively than OxPhos uncoupler 2,4-dinitrophenol. Apparently, quiescent sperm employ the most energy efficient OxPhos to survive for extended periods of time under extreme conditions of nutrition and crowding. However, on motility initiation, sperm switch predominantly to glycolysis to cater to their high- and quick-energy requirement of much shorter periods. This study also presents a proof of concept for targeting sperm energy metabolism for contraception. © 2016 by the Society for the Study of Reproduction, Inc.

  15. Clusters – a modern way of cooperation enhancing the competitiveness of the horticultural enterprises from the Republic of Moldova

    Directory of Open Access Journals (Sweden)

    GOLBAN Artur

    2015-12-01

    Full Text Available Contemporary enterprises represent a modern way of cooperation between people, while the relations between these enterprises and other organizations represent an advanced stage in the hierarchy of cooperation. This scientific article analyses the possibility of cooperation between the apple producing agricultural enterprises from the Republic of Moldova through clusters, which supposes both the collaboration between the agricultural enterprises and with the research-innovation sector. All over the world clusters represent a tool for economic and social renovation. The creation of apple clusters will help horticultural producers to cooperate more efficiently with each other and to solve the problems of the fruit and vegetable growers within the horticultural cluster. A special place in the cluster apple model is revealed by the Project “Livada Mea” financed by European Bank for Investments in total amount of 120 mln EUR. The purpose of the project was to modernize the value chain of the horticultural sector in the Republic of Moldova. The main objective of the given research is to emphasize the importance of clusters as a modern way of cooperation enhancing the competitiveness of the horticultural enterprises from the Republic of Moldova. Rezumat. Întreprinderile contemporane reprezintă o formă modernă de cooperare între oameni, în timp ce relaţiile dintre aceste întreprinderi şi alte organizaţii reprezintă o treaptă avansată în ierarhia cooperării. În acest articol se analizează posibilitatea cooperării întreprinderilor agricole producătoare de mere din Republica Moldova prin crearea de clustere, care presupune colaborarea atât între întreprinderile agricole, cât şi cu sectorul de cercetare-inovare. În toată lumea clusterele reprezintă un instrument pentru renovare economică şi socială. Crearea clusterului mărului va ajuta producătorii horticoli să coopereze mai eficient între ei şi să soluţioneze

  16. Possible Removal of Rival Sperm by the Elongated Genitalia of the Earwig, Euborellia plebeja.

    Science.gov (United States)

    Kamimura, Y

    2000-07-01

    Sperm displacement is a sperm competition avoidance mechanism that reduces the paternity of males that have already mated with the female. Direct anatomical sperm removal or sperm flushing is known to occur in four insect orders: Odonata, Orthoptera, Coleoptera and Hymenoptera. In a fifth order, Dermaptera (earwigs), I found that the virga (the elongated rod of the male genitalia) of Euborellia plebeja seems to be used to remove rival sperm from the spermatheca (a fine-tubed female sperm storage organ). In this species, copulation lasted on average 4.6 minutes, during which time the male inserted the virga deep into the spermatheca, and then extracted it ejaculating semen from the opening of the virgal tip. The extraction of virgae (with its brim-like tip) appeared to cause removal of stored sperm in the spermatheca. The virga was as long as the body length of males, and the spermatheca was twice the female body length. The long length of the spermatheca and the possible removal function of the virga may select for virgal elongation.

  17. Tribulus terrestris Extract Improves Human Sperm Parameters In Vitro

    Science.gov (United States)

    Khaleghi, Sara; Bakhtiari, Mitra; Asadmobini, Atefeh; Esmaeili, Farzane

    2016-01-01

    Objective. The object of present study was to investigate the effects of direct addition of Tribulus terrestris extract on human sperm parameters. Design. Semen specimens from 40 healthy men volunteers were divided into 4 groups: one group received no treatment (control group) while the others were incubated with 20, 40, and 50 µg/mL of T terrestris extract (experimental groups). Motility, viability, and DNA fragmentation were assessed in all groups. Results. The incubation of human semen with 40 and 50 μg/mL of T terrestris extract significantly enhanced total sperm motility, number of progressive motile spermatozoa, and curvilinear velocity over 60 to 120 minutes’ holding time (P terrestris extract (P terrestris extract to human sperm could affect male fertility capacity. PMID:27694560

  18. Tribulus terrestris Extract Improves Human Sperm Parameters In Vitro.

    Science.gov (United States)

    Khaleghi, Sara; Bakhtiari, Mitra; Asadmobini, Atefeh; Esmaeili, Farzane

    2016-09-30

    The object of present study was to investigate the effects of direct addition of Tribulus terrestris extract on human sperm parameters. Semen specimens from 40 healthy men volunteers were divided into 4 groups: one group received no treatment (control group) while the others were incubated with 20, 40, and 50 µg/mL of T terrestris extract (experimental groups). Motility, viability, and DNA fragmentation were assessed in all groups. The incubation of human semen with 40 and 50 μg/mL of T terrestris extract significantly enhanced total sperm motility, number of progressive motile spermatozoa, and curvilinear velocity over 60 to 120 minutes' holding time (P terrestris extract (P terrestris extract to human sperm could affect male fertility capacity. © The Author(s) 2016.

  19. Heat shock protein 90 has roles in intracellular calcium homeostasis, protein tyrosine phosphorylation regulation, and progesterone-responsive sperm function in human sperm.

    Science.gov (United States)

    Li, Kun; Xue, Yamei; Chen, Aijun; Jiang, Youfang; Xie, Haifeng; Shi, Qixian; Zhang, Songying; Ni, Ya

    2014-01-01

    Heat shock protein 90 plays critical roles in client protein maturation, signal transduction, protein folding and degradation, and morphological evolution; however, its function in human sperm is not fully understood. Therefore, our objective in this study was to elucidate the mechanism by which heat shock protein 90 exerts its effects on human sperm function. By performing indirect immunofluorescence staining, we found that heat shock protein 90 was localized primarily in the neck, midpiece, and tail regions of human sperm, and that its expression increased with increasing incubation time under capacitation conditions. Geldanamycin, a specific inhibitor of heat shock protein 90, was shown to inhibit this increase in heat shock protein 90 expression in western blotting analyses. Using a multifunctional microplate reader to examine Fluo-3 AM-loaded sperm, we observed for the first time that inhibition of heat shock protein 90 by using geldanamycin significantly decreased intracellular calcium concentrations during capacitation. Moreover, western blot analysis showed that geldanamycin enhanced tyrosine phosphorylation of several proteins, including heat shock protein 90, in a dose-dependent manner. The effects of geldanamycin on human sperm function in the absence or presence of progesterone was evaluated by performing chlortetracycline staining and by using a computer-assisted sperm analyzer. We found that geldanamycin alone did not affect sperm capacitation, hyperactivation, and motility, but did so in the presence of progesterone. Taken together, these data suggest that heat shock protein 90, which increases in expression in human sperm during capacitation, has roles in intracellular calcium homeostasis, protein tyrosine phosphorylation regulation, and progesterone-stimulated sperm function. In this study, we provide new insights into the roles of heat shock protein 90 in sperm function.

  20. Sperm cleanup and centrifugation processing for cryopreservation.

    Science.gov (United States)

    Sieme, Harald; Oldenhof, Harriëtte

    2015-01-01

    Fertility rates with artificial insemination are highest with good-quality sperm samples. Therefore, nonviable sperm, cellular debris, and seminal plasma are preferably removed from semen samples prior to use or for preservation. Such compounds are sources where reactive oxygen species are generated during storage or upon cryopreservation, impairing sperm function. In this chapter we describe methods to remove seminal plasma and cellular debris from sperm samples, and for selecting morphologically normal motile sperm. The methods that are described here include: ordinary centrifugation, sperm swim-up, glass wool and Sephadex filtration/adherence, and single-layer as well as discontinuous two-layer iodixanol density gradient centrifugation.

  1. Evaluation of cholesterol- treated dromedary camel sperm function by heterologous IVF and AI.

    Science.gov (United States)

    Crichton, Elizabeth G; Malo, Clara; Pukazhenthi, Budhan S; Nagy, Peter; Skidmore, Julian A

    2016-11-01

    Cholesterol (cholesterol-loaded cyclodextrins: CLC) treatment of dromedary camel sperm prior to freezing enhances cryosurvival. The present study first validated the efficacy of a heterologous zona-free goat oocyte assay (n=115 oocytes) to evaluate camel sperm function in vitro (Experiment 1: n=6 bulls), then examined the effects of CLC treatment (1.5mg/mL CLC; CLC+) versus no treatment (0 CLC) of fresh (Experiment 2: n=4 bulls) and frozen-thawed (Experiment 3: n=5 bulls) camel sperm to penetrate, de-condense and form pro-nuclei in in vitro-matured goat oocytes. Finally, the ability of fresh 0 CLC and CLC+ sperm to fertilize in vivo was studied by artificially inseminating super-ovulated females (n=7-9 per treatment) and examining embryo production (Experiment 4: n=4-5 bulls/treatment). Camel spermatozoa penetrated (60%) and formed pro-nuclei (33%) in goat oocytes demonstrating the utility of this heterologous system for assessing sperm function in vitro. For fresh spermatozoa, 0 CLC-treated sperm performed better than their CLC+ counterparts for all parameters measured (Psperm-oocyte interaction in 0 CLC aliquots but remained unaltered in CLC+ aliquots demonstrating a protective effect of cholesterol treatment. There was no difference between treatments in the in vitro fertilizing ability of frozen-thawed sperm or in the numbers of embryos retrieved following AI with fresh 0 CLC or CLC+ sperm. We conclude that although CLC treatment of dromedary camel sperm improves sperm motility it fails to confer an advantage to them in terms of improved in vitro sperm-oocyte interaction or in vivo fertilization under the conditions tested. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Multicriteria Decision Analysis to Develop Effective Sustainable Development Strategies for Enhancing Competitive Advantages: Case of the TFT-LCD Industry in Taiwan

    Directory of Open Access Journals (Sweden)

    Iuan-Yuan Lu

    2016-07-01

    Full Text Available In the Internet of Things era, panel displays play a major role in human life, because humans frequently use liquid crystal displays to monitor their electrical devices. The display industry creates remarkable economic output, but every manufacturing process inevitably has some undesirable effects on the environment. With the increasing awareness of environmental protection, balanced development is necessary to address the emerging market trends. However, short-sighted manufacturing corporations that focus solely on financial performance can achieve only short-term profits. The purpose of this study was to develop the most effective sustainable improvement strategies that can enhance competitive advantages in real-world situations. The proposed method combines the balanced scorecard and a new hybrid modified multiple attribute decision-making model which together adopt the DEMATEL technique to construct the influential network relation map and develop the DEMATEL-based ANP with the VIKOR method to deliver strategies that integrate environmental sustainability and competitive advantage. Finally, a real-world case study applying the proposed method to the cases of liquid crystal display manufacturers was conducted. Then, this paper discusses the effective use of natural resources, development of enterprises, and sustainable competitive advantage in this context. Various manufacturers, communities, and stakeholders can benefit from the coopetition solutions explained by the proposed method.

  3. EDITORIAL: Physics competitions Physics competitions

    Science.gov (United States)

    Jordens, H.; Mathelitsch, L.

    2011-07-01

    and Astrophysics. Those in charge of the competition give an overview of this relatively young tournament. They give a few examples of theoretical and experimental tasks, and one can see the strong connection between astronomy and physics, between the large scales in the universe and the small scales in particle physics. The third paper introduces a special competition called 'First Step to Nobel Prize in Physics'. It was conceived as a national event in Poland and has gained international reputation and acceptance since 1992. Papers are submitted from young students prior to university and are refereed in the same manner as real research papers. This means that the most important criterion is the originality and novelty of the activity performed in theoretical or experimental physics. The aims of this competition are set out below and can be seen as a credo for all competitions: promotion of scientific interest among young pupils selection and promotion of outstanding pupils enhancing motivation stimulation of school work establishing friendly relations between young physicists.

  4. Cryopreservation of non-human primate sperm: priorities for future research.

    Science.gov (United States)

    Morrell, J M; Hodges, J K

    1998-10-01

    Wild populations of many non-human primate species have declined alarmingly due to habitat destruction, hunting and genetic isolation. Captive breeding programmes to aid species survival could be enhanced by the use of assisted reproductive techniques, such as artificial insemination (AI), if a source of viable sperm was readily accessible. Cryobanks of primate sperm could provide such a supply if techniques for freezing sperm could be developed. Although sporadic attempts to cryopreserve primate sperm have been reported for some of the more frequently encountered zoo-maintained species, there is limited information available on techniques for sperm collection and storage. It is vital that adequate reporting of all cryopreservation attempts be made to avoid repetition of inappropriate methodologies and wastage of valuable genetic material from rare or endangered animals. An integrated approach to the cryobanking of non-human primate sperm is considered to be essential for species conservation. In this review, the factors affecting the success of sperm cryopreservation are outlined, existing information is compiled from previous reported attempts at cryopreservation, and suggestions are made for cryopreserving sperm in further non-human primate species. Moreover, recommendations are given for additional studies to augment existing data. It is intended that this information should serve as a guide for developing cryopreservation protocols in the future, particularly for endangered species.

  5. Make it spin: individual trapping of sperm for analysis and recovery using micro-contact printing.

    Science.gov (United States)

    Frimat, J-P; Bronkhorst, M; de Wagenaar, B; Bomer, J G; van der Heijden, F; van den Berg, A; Segerink, L I

    2014-08-07

    In this article, we describe the development of a high throughput platform to spatially manipulate viable sperm for motility measurements and recovery of the best single sperm for fertilization purposes. Micro-contact printing was used to pattern islands of adhesive proteins (fibronectin) separated by sperm repellent species (Pluronic acid F-127) on commercially available polystyrene substrates. Following washing, arrays of viable single sperm were captured onto the islands demonstrating for the first time that sperm can be trapped by micro-contact printing with patterning efficiency of 90% while retaining 100% viability. These were then subjected to motility analysis whilst remaining spatially confined to the islands. Single sperm motility was assessed (n = 37) by software analysis measuring the number of rotations per second (degrees s⁻¹). The assignment of array coordinates allows the more active single sperm to be easily identified and recovered by a simple micromanipulator pipette aspiration step with automated possibility for assisted reproductive technologies or further quality correlation analysis. Taken together, we show for the first time a technique to simultaneously screen thousands of viable single sperm for motility assessment while retaining the ability for single species recovery for enhanced fertilization purposes.

  6. Challenges in Development of Sperm Repositories for Biomedical Fishes: Quality Control in Small-Bodied Species.

    Science.gov (United States)

    Torres, Leticia; Liu, Yue; Guitreau, Amy; Yang, Huiping; Tiersch, Terrence R

    2017-12-01

    Quality control (QC) is essential for reproducible and efficient functioning of germplasm repositories. However, many biomedical fish models present significant QC challenges due to small body sizes (<5 cm) and miniscule sperm volumes (<5 μL). Using minimal volumes of sperm, we used Zebrafish to evaluate common QC endpoints as surrogates for fertilization success along sequential steps of cryopreservation. First, concentrations of calibration bead suspensions were evaluated with a Makler ® counting chamber by using different sample volumes and mixing methods. For sperm analysis, samples were initially diluted at a 1:30 ratio with Hanks' balanced salt solution (HBSS). Motility was evaluated by using different ratios of sperm and activation medium, and membrane integrity was analyzed with flow cytometry at different concentrations. Concentration and sperm motility could be confidently estimated by using volumes as small as 1 μL, whereas membrane integrity required a minimum of 2 μL (at 1 × 10 6 cells/mL). Thus, <5 μL of sperm suspension (after dilution to 30-150 μL with HBSS) was required to evaluate sperm quality by using three endpoints. Sperm quality assessment using a combination of complementary endpoints enhances QC efforts during cryopreservation, increasing reliability and reproducibility, and reducing waste of time and resources.

  7. Female sperm storage in reptiles.

    Science.gov (United States)

    Sever, David M; Hamlett, William C

    2002-02-01

    Internal fertilization and oviparity most likely are symplesiomorphies for modern reptiles, and viviparity has evolved independently numerous times in Sauria and Serpentes. Oviducal sperm storage is known in females of all taxa except Amphisbaenia. However, in Rhynchocephalia and Crocodilia, sperm storage is poorly studied, and specialized sperm storage tubules (Ssts) are unknown. We use the molecular phylogenetic hypothesis [(Chelonia+Archosauria) (Squamata)] to trace evolution of sperm storage characters. Ssts arose independently in Chelonia and Squamata. Turtles possess albumen-secreting glands in the anterior half of the oviduct (the tuba or isthmus), and the most distal of these glands also serve as Ssts; in addition, some turtles possess Ssts in the adjacent segment of the oviduct, the uterus. Squamates lack albumen-secreting glands, and the ancestral state is possession of Ssts in the posterior infundibulum (uterine tube). Secondarily, iguanids have evolved vaginal Ssts. In this paper, we present the first ultrastructural observations on vaginal Ssts in lizards, using Anolis sagrei (Polychrotidae). Proximally, the neck of these simple tubular glands continues the alternation of ciliated and secretory cells lining the lumen of the vagina. However, the epithelial cells of the distal sperm storage area are neither secretory nor ciliated. The Ssts of Anolis are more similar to those of birds more than to infundibular receptacles in snakes and lizards. Copyright 2002 Wiley-Liss, Inc.

  8. Determinants of mating and sperm-transfer success in a simultaneous hermaphrodite.

    Science.gov (United States)

    Janicke, T; Schärer, L

    2009-02-01

    The number of mating partners an individual has within a population is a crucial parameter in sex allocation theory for simultaneous hermaphrodites because it is predicted to be one of the main parameters influencing sex allocation. However, little is known about the factors that determine the number of mates in simultaneous hermaphrodites. Furthermore, in order to understand the benefits obtained by resource allocation into the male function it is important to identify the factors that predict sperm-transfer success, i.e. the number of sperm a donor manages to store in a mate. In this study we experimentally tested how social group size (i.e. the number of all potential mates within a population) and density affect the number of mates and sperm-transfer success in the outcrossing hermaphroditic flatworm Macrostomum lignano. In addition, we assessed whether these parameters covary with morphological traits, such as body size, testis size and genital morphology. For this we used a method, which allows tracking sperm of a labelled donor in an unlabelled mate. We found considerable variation in the number of mates and sperm-transfer success between individuals. The number of mates increased with social group size, and was higher in worms with larger testes, but there was no effect of density. Similarly, sperm-transfer success was affected by social group size and testis size, but in addition this parameter was influenced by genital morphology. Our study demonstrates for the first time that the social context and the morphology of sperm donors are important predictors of the number of mates and sperm-transfer success in a simultaneous hermaphrodite. Based on these findings, we hypothesize that sex allocation influences the mating behaviour and outcome of sperm competition.

  9. Psychosocial counselling of identifiable sperm donors

    NARCIS (Netherlands)

    Visser, M.; Mochtar, M.H.; de Melker, A.A.; van der Veen, F.; Repping, S.; Gerrits, T.

    2016-01-01

    STUDY QUESTION: What do identifiable sperm donors feel about psychosocial counselling? SUMMARY ANSWER: Identifiable sperm donors found it important that psychosocial counselling focused on emotional consequences and on rules and regulations and they expected to have access to psychosocial

  10. Psychosocial counselling of identifiable sperm donors

    NARCIS (Netherlands)

    Visser, M. [=Marja; Mochtar, M. H.; de Melker, A. A.; van der Veen, F.; Repping, S.; Gerrits, T.

    2016-01-01

    What do identifiable sperm donors feel about psychosocial counselling? Identifiable sperm donors found it important that psychosocial counselling focused on emotional consequences and on rules and regulations and they expected to have access to psychosocial counselling at the time that

  11. Role of Ecological Cultural Synthesis in Enhancement of Importance and Competitive Ability of Polytechnic Education in the Southern Far East of the Russian Federation

    Science.gov (United States)

    Petukhov, V. I.; Golikov, S. Yu; Maiorov, I. S.

    2017-11-01

    The regional features of polytechnic education development under present-day conditions are considered. The enhanced role of ecological cultural synthesis is proved to be necessary in order to enhance the importance and competitive ability of the polytechnic education in the southern Far East of the Russian Federation. Ecological cultural synthesis is the major condition to turn natural management into the ecologically sparing management of natural resources; it is also a method of a person to learn nature and the mutual relations with nature. It should become a basis for educational programs in the higher schools of the Russian Federation (that may be used with the practical purposes not only in the Russian Federation), and it may promote the search of the national idea, ideological core, and basic principles of further education development in Russia.

  12. Sperm traits negatively covary with size and asymmetry of a secondary sexual trait in a freshwater crayfish

    OpenAIRE

    Galeotti, P.; Bernini, G.; Locatello, L.; Sacchi, R.; Fasola, M.; Rubolini, D.

    2012-01-01

    In species where females mate promiscuously, the reproductive success of males depends both on their ability to acquire mates (pre-copulatory sexual selection) and ability of their ejaculates to outcompete those of other males (post-copulatory sexual selection). Sperm competition theory predicts a negative relationship between investment in body traits favouring mate acquisition (secondary sexual characters, SSCs) and investment in ejaculate size or quality, due to the inherent costs of sperm...

  13. Boundaries of Ethics, Sperm on the Border –The Globalization of Danish Sperm

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    During the past two decades, Denmark has developed into an important destination for fertility travelers in need of donor sperm. A variety of different clinics providing sperm with different modes of clinical care have developed, and an increasing number of their customers come from abroad. One...... of the reasons why Danish fertility clinics have enabled women from Denmark and abroad to turn to sperm donation is, that two of the largest sperm banks in Europe are Danish. In contrast to many other countries where sperm is in demand, the Danish sperm banks are able to provide enough sperm for the national...... market as well as clinics worldwide. Furthermore, one of the sperm banks market sperm for self-insemination and deliver it to private customers by UPS. Although sperm donation is an old and low technology compared to other reproductive technologies, this development has taken place at the same time...

  14. Postcopulatory sexual selection is associated with accelerated evolution of sperm morphology

    Czech Academy of Sciences Publication Activity Database

    Rowe, M.; Albrecht, Tomáš; Cramer, E. R. A.; Johnsen, A.; Laskemoen, T.; Weir, J. T.; Lifjeld, J. T.

    2015-01-01

    Roč. 69, č. 4 (2015), s. 1044-1052 ISSN 0014-3820 R&D Projects: GA ČR(CZ) GAP506/12/2472 Institutional support: RVO:68081766 Keywords : birds * evolutionary diversification * evolutionary rate * passerine * sperm competition Subject RIV: EG - Zoology Impact factor: 4.007, year: 2015

  15. Last mated male sperm precedence in doubly mated females is not ...

    Indian Academy of Sciences (India)

    DST Unit on Evolution and Genetics, Department of Studies in Zoology, University of Mysore, Manasagangotri, ... sperm competition has been studied in different species of. Drosophila, such a .... Proportions of first male and second male progeny of doubly mated female and the results of paired-sample t-test carried out.

  16. Bioenergetics of mammalian sperm capacitation.

    Science.gov (United States)

    Ferramosca, Alessandra; Zara, Vincenzo

    2014-01-01

    After ejaculation, the mammalian male gamete must undergo the capacitation process, which is a prerequisite for egg fertilization. The bioenergetics of sperm capacitation is poorly understood despite its fundamental role in sustaining the biochemical and molecular events occurring during gamete activation. Glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) are the two major metabolic pathways producing ATP which is the primary source of energy for spermatozoa. Since recent data suggest that spermatozoa have the ability to use different metabolic substrates, the main aim of this work is to present a broad overview of the current knowledge on the energy-producing metabolic pathways operating inside sperm mitochondria during capacitation in different mammalian species. Metabolism of glucose and of other energetic substrates, such as pyruvate, lactate, and citrate, is critically analyzed. Such knowledge, besides its obvious importance for basic science, could eventually translate into the development of novel strategies for treatment of male infertility, artificial reproduction, and sperm selection methods.

  17. The More, the Merrier: Why and How Employee-Driven Eco-Innovation Enhances Environmental and Competitive Advantage

    Directory of Open Access Journals (Sweden)

    Anke Buhl

    2016-09-01

    Full Text Available Innovative solutions are often conjured as a key factor for companies to come closer to the goal of ecological sustainability. Furthermore, proactive eco-innovation activities can encompass competitive advantages. Companies are therefore well advised to tap any available source of innovation. However, although employees’ innovative capacity has often been described, to date, their manifold potentials for eco-innovation processes have hardly been examined in detail. The overarching research questions guiding this conceptual paper are why and how employee participation in eco-innovation processes can entail environmental and competitive advantages for companies. The authors introduce the concept of employee-driven eco-innovation (EDEI, defined here as ordinary employees’ voluntary engagement in innovation activities within an organizational context that, intentionally or not, lead to environmental improvements. This paper complements previous literature on employee-driven innovation (EDI by applying it to the specific case of eco-innovation. In this context, employees’ comprehensive environmental competences resulting from “tacit knowledge”, “private consumer experience” and “green identity” are taken into account. In addition, we delineate critical intra-organizational factors for EDEI activities and illustrate green employees’ specific requirements in this regard.

  18. Microfluidic single sperm entrapment and analysis

    NARCIS (Netherlands)

    de Wagenaar, B.; Berendsen, Johanna Theodora Wilhelmina; Berendsen, J.T.W.; Bomer, Johan G.; Olthuis, Wouter; van den Berg, Albert; Segerink, Loes Irene

    2015-01-01

    Selection of healthy spermatozoa is of crucial importance for the success rates of assisted reproduction technologies (ART) such as in vitro fertilization and intra-cytoplasmic sperm injection. Although sperm selection for ART procedures is predominantly based on sperm motility, successful

  19. Sperm traits negatively covary with size and asymmetry of a secondary sexual trait in a freshwater crayfish.

    Science.gov (United States)

    Galeotti, Paolo; Bernini, Guido; Locatello, Lisa; Sacchi, Roberto; Fasola, Mauro; Rubolini, Diego

    2012-01-01

    In species where females mate promiscuously, the reproductive success of males depends both on their ability to acquire mates (pre-copulatory sexual selection) and ability of their ejaculates to outcompete those of other males (post-copulatory sexual selection). Sperm competition theory predicts a negative relationship between investment in body traits favouring mate acquisition (secondary sexual characters, SSCs) and investment in ejaculate size or quality, due to the inherent costs of sperm production. In contrast, the phenotype-linked fertility hypothesis posits that male fertilizing efficiency is reliably reflected by the phenotypic expression of male SSCs, allowing females to obtain direct benefits by selecting more ornamented males as copulation partners. In this study, we investigated the relationships between male SSCs and size and quality (viability and longevity) of ejaculates allocated to females in mating trials of the freshwater crayfish Austropotamobius italicus. We showed that the relative size of male weapons, the chelae, was negatively related to ejaculate size, and that chelae asymmetry, resulting from regeneration of lost chelipeds, negatively covaried with sperm longevity. Moreover, males allocated more viable sperm to mates from their own rather than different stream of origin. Our findings thus suggest that, according to sperm competition theory, pre-copulatory sexual selection for large weapons used in male fighting may counteract post-copulatory sperm competition in this crayfish species, and that investment in cheliped regeneration may impair ejaculate quality.

  20. Sperm traits negatively covary with size and asymmetry of a secondary sexual trait in a freshwater crayfish.

    Directory of Open Access Journals (Sweden)

    Paolo Galeotti

    Full Text Available In species where females mate promiscuously, the reproductive success of males depends both on their ability to acquire mates (pre-copulatory sexual selection and ability of their ejaculates to outcompete those of other males (post-copulatory sexual selection. Sperm competition theory predicts a negative relationship between investment in body traits favouring mate acquisition (secondary sexual characters, SSCs and investment in ejaculate size or quality, due to the inherent costs of sperm production. In contrast, the phenotype-linked fertility hypothesis posits that male fertilizing efficiency is reliably reflected by the phenotypic expression of male SSCs, allowing females to obtain direct benefits by selecting more ornamented males as copulation partners. In this study, we investigated the relationships between male SSCs and size and quality (viability and longevity of ejaculates allocated to females in mating trials of the freshwater crayfish Austropotamobius italicus. We showed that the relative size of male weapons, the chelae, was negatively related to ejaculate size, and that chelae asymmetry, resulting from regeneration of lost chelipeds, negatively covaried with sperm longevity. Moreover, males allocated more viable sperm to mates from their own rather than different stream of origin. Our findings thus suggest that, according to sperm competition theory, pre-copulatory sexual selection for large weapons used in male fighting may counteract post-copulatory sperm competition in this crayfish species, and that investment in cheliped regeneration may impair ejaculate quality.

  1. Assessment of sperm competition by European bitterling, Rhodeus sericeus

    Czech Academy of Sciences Publication Activity Database

    Smith, C.; Reichard, Martin; Jurajda, Pavel

    2003-01-01

    Roč. 53, č. 4 (2003), s. 206-213 ISSN 0340-5443 Institutional research plan: CEZ:AV0Z6093917 Keywords : Acheilognathinae * alternative mating tactics * ESS model Subject RIV: EG - Zoology Impact factor: 2.649, year: 2003

  2. Solea senegalensis sperm cryopreservation: New insights on sperm quality.

    Directory of Open Access Journals (Sweden)

    Marta F Riesco

    Full Text Available Cryopreservation of Senegalese sole sperm can represent an alternative to overcome some reproductive problems of this species. However, it is important to guarantee the safe use of cryopreserved sperm by selecting an appropriate protocol according to a high demand quality need to be ensured. It has been demonstrated that traditional assays such as motility and viability do not provide enough information to identify specific damage caused by cryopreservation process (freezing and thawing. Specific tests, including lipid peroxidation and DNA damage, should be performed. In the present study, motility and lipid peroxidation were performed as specific tests allowing us to discard cryopreservation conditions such as methanol as internal cryoprotectant and bovine serum albumin as external cryoprotectant. In addition, a caspase 3/7 detection by flow cytometry was performed to analyze apoptosis activity in the best selected conditions. Moreover, new highly sensitive tests based on transcript number detection have recently been described in fish sperm cryopreservation. For this reason, a transcript level detection assay was performed on certain oxidative and chaperone genes related to fertilization ability and embryo development (hsp70, hsp90BB, hsp90AA, gpx to select the best cryopreservation conditions. DMSO+ egg yolk proved to be the best cryoprotectant combination in terms of transcript level. This study describes an optimized cryopreservation protocol for Solea senegalensis sperm demonstrating for the first time that transcript degradation is the most sensitive predictor of cell status in this species after cryopreservation.

  3. Pseudomonas fluorescens F113 Mutant with Enhanced Competitive Colonization Ability and Improved Biocontrol Activity against Fungal Root Pathogens ▿

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-01-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible. PMID:21685161

  4. Pseudomonas fluorescens F113 mutant with enhanced competitive colonization ability and improved biocontrol activity against fungal root pathogens.

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-08-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible.

  5. Effects of lentivirus-mediated CREB expression in the dorsolateral striatum: memory enhancement and evidence for competitive and cooperative interactions with the hippocampus.

    Science.gov (United States)

    Kathirvelu, Balachandar; Colombo, Paul J

    2013-11-01

    Neural systems specialized for memory may interact during memory formation or recall, and the results of interactions are important determinants of how systems control behavioral output. In two experiments, we used lentivirus-mediated expression of the transcription factor CREB (LV-CREB) to test if localized manipulations of cellular plasticity influence interactions between the hippocampus and dorsolateral striatum. In Experiment 1, we tested the hypothesis that infusion of LV-CREB in the dorsolateral striatum facilitates memory for response learning, and impairs memory for place learning. LV-CREB in the dorsolateral striatum had no effect on response learning, but impaired place memory; a finding consistent with competition between the striatum and hippocampus. In Experiment 2, we tested the hypothesis that infusion of LV-CREB in the dorsolateral striatum facilitates memory for cue learning, and impairs memory for contextual fear conditioning. LV-CREB in the dorsolateral striatum enhanced memory for cue learning and, in contrast to our prediction, also enhanced memory for contextual fear conditioning, consistent with a cooperative interaction between the striatum and hippocampus. Overall, the current experiments demonstrate that infusion of LV-CREB in the dorsolateral striatum (1) increases levels of CREB protein locally, (2) does not alter acquisition of place, response, cue, or contextual fear conditioning, (3) facilitates memory for cue learning and contextual fear conditioning, and (4) impairs memory for place learning. Taken together, the present results provide evidence that LV-CREB in the dorsolateral striatum can enhance memory formation and cause both competitive and cooperative interactions with the hippocampus. Copyright © 2013 Wiley Periodicals, Inc.

  6. Fluorescent sperm in a transparent worm: validation of a GFP marker to study sexual selection.

    Science.gov (United States)

    Marie-Orleach, Lucas; Janicke, Tim; Vizoso, Dita B; Eichmann, Micha; Schärer, Lukas

    2014-06-30

    Sexual selection has initially been thought to occur exclusively at the precopulatory stage in terms of contests among males and female mate choice, but research over the last four decades revealed that it often continues after copulation through sperm competition and cryptic female choice. However, studying these postcopulatory processes remains challenging because they occur internally and therefore are often difficult to observe. In the transparent free-living flatworm Macrostomum lignano, a recently established transgenic line that expresses green fluorescent protein (GFP) in all cell types, including sperm, offers a unique opportunity to non-invasively visualise and quantify the sperm of a GFP-expressing donor inside the reproductive tract of wild-type recipients in vivo. We here test several aspects of the reproductive performance of the transgenic individuals and the accuracy of the techniques involved in assessing the GFP-expressing worms and their sperm. We then show the usefulness of these methods in a study on sperm displacement. GFP-expressing worms do not differ from wild-type worms in terms of morphology, mating rate and reproductive success. In addition, we show that the GFP signal is reliably and unequivocally expressed by all GFP-expressing individuals observed under epifluorescence illumination. However, the intensity of the GFP signal emitted by sperm of GFP expressing donors can vary (which we show to be at least in part due to sperm ageing) and the GFP marker is inherited according to Mendel's laws in most, but not all, of the individuals. Nevertheless, we argue these two issues can be addressed with an appropriate experimental design. Finally, we demonstrate the value of the GFP-techniques by comparing the number of GFP-expressing sperm in a wild-type recipient before and after mating with a competing sperm donor, providing clear experimental evidence for sperm displacement in M. lignano. This result suggests that sperm donors can displace

  7. Retail competition

    International Nuclear Information System (INIS)

    1998-01-01

    Retail competition as the cornerstone of a competitive electricity marketplace was the subject of the seventh in the series of policy discussion papers developed at the Market Design Conference. Concern was expressed that because of the complexities involved in market design and technical implementation, the retail competition may lag behind other elements of the implementation of the new market design. A variety of key issues were debated, including the role of physical versus financial contracts, the form of retail competition and financial settlement systems in the short term, the requirement to separate 'competitive' (metering, billing, maintenance, consumer education) from non-competitive' (the transmission wires) services and the role of municipal electric utilities. It was agreed that the IMO should play an important role in defining and enforcing the separation of services, and that as a general rule, the development of policy in this area should be guided by the principle of maximizing the potential for competition

  8. Cat fertilization by mouse sperm injection.

    Science.gov (United States)

    Jin, Yong-Xun; Cui, Xiang-Shun; Yu, Xian-Feng; Lee, Sung-Hyun; Wang, Qing-Ling; Gao, Wei-Wei; Xu, Yong-Nan; Sun, Shao-Chen; Kong, Il-Keun; Kim, Nam-Hyung

    2012-11-01

    Interspecies intracytoplasmic sperm injection has been carried out to understand species-specific differences in oocyte environments and sperm components during fertilization. While sperm aster organization during cat fertilization requires a paternally derived centriole, mouse and hamster fertilization occur within the maternal centrosomal components. To address the questions of where sperm aster assembly occurs and whether complete fertilization is achieved in cat oocytes by interspecies sperm, we studied the fertilization processes of cat oocytes following the injection of cat, mouse, or hamster sperm. Male and female pronuclear formations were not different in the cat oocytes at 6 h following cat, mouse or hamster sperm injection. Microtubule asters were seen in all oocytes following intracytoplasmic injection of cat, mouse or hamster sperm. Immunocytochemical staining with a histone H3-m2K9 antibody revealed that mouse sperm chromatin is incorporated normally with cat egg chromatin, and that the cat eggs fertilized with mouse sperm enter metaphase and become normal 2-cell stage embryos. These results suggest that sperm aster formation is maternally dependent, and that fertilization processes and cleavage occur in a non-species specific manner in cat oocytes.

  9. Etiologies of sperm oxidative stress

    Directory of Open Access Journals (Sweden)

    Parvin Sabeti

    2016-04-01

    Full Text Available Sperm is particularly susceptible to reactive oxygen species (ROS during critical phases of spermiogenesis. However, the level of seminal ROS is restricted by seminal antioxidants which have beneficial effects on sperm parameters and developmental potentials. Mitochondria and sperm plasma membrane are two major sites of ROS generation in sperm cells. Besides, leukocytes including polymer phonuclear (PMN leukocytes and macrophages produce broad category of molecules including oxygen free radicals, non-radical species and reactive nitrogen species. Physiological role of ROS increase the intracellular cAMP which then activate protein kinase in male reproductive system. This indicates that spermatozoa need small amounts of ROS to acquire the ability of nuclear maturation regulation and condensation to fertilize the oocyte. There is a long list of intrinsic and extrinsic factors which can induce oxidative stress to interact with lipids, proteins and DNA molecules. As a result, we have lipid peroxidation, DNA fragmentation, axonemal damage, denaturation of the enzymes, over generation of superoxide in the mitochondria, lower antioxidant activity and finally abnormal spermatogenesis. If oxidative stress is considered as one of the main cause of DNA damage in the germ cells, then there should be good reason for antioxidant therapy in these conditions

  10. Antibiotics supplemented culture media can eliminate non-specific bacteria from human semen during sperm preparation for intra uterine insemination

    Directory of Open Access Journals (Sweden)

    D. M. A. B. Dissanayake

    2014-01-01

    Full Text Available Rationale: Bacterial flora can be isolated from many semen samples of subfertile males. Bacteriospermia can compromise the outcome of intra uterine insemination (IUI by contaminating the post-processed sperm sample. Objectives: The objective of the present study is to determine the efficacy of penicillin and streptomycin in eliminating the bacteria from semen samples in the sperm processing procedure, and to assess the effects of antibiotics on sperm motility, survivability, and pregnancy rates. Design and Settings: A prospectively controlled study was carried out using couples undergoing IUI with their informed consent. Intervention: Sperm processing using the swim-up technique in penicillin and streptomycin supplemented culture medium. Subjects And Methods: Couples were consecutively allocated in two groups for sperm processing (a Group AB+ (antibiotics supplemented culture medium, n = 33 and (b Group AB− (antibiotic free culture medium, n = 33. Semen culture was performed before and after sperm processing. Sperm motility was assessed immediately after processing and after 24 h of incubation. Results: Bacterial isolates were found in 20 (60.6% and 22 (66.1% of samples before processing in Groups AB+ and AB− respectively. Addition of antibiotics resulted in completely eliminating non-specific bacteria from semen samples without affecting sperm motility. In vitro survival rate of sperm enhanced in AB+ group compared with AB− group (motile sperm after 24 h, 62.21% (standard deviation [SD]: 37.27 versus 41.36% (SD: 30.78, P = 0.012. Pregnancy rate, was comparable between two groups (9% in Group AB+ vs. 6% in Group AB−, P = 0.45. Conclusion: Penicillin streptomycin combination could completely eliminate non-specific bacteria from semen samples during sperm processing in this population. The types of antibiotics and dosage used did not seem to have any harmful effects on human sperm.

  11. Green revolution trees: semidwarfism transgenes modify gibberellins, promote root growth, enhance morphological diversity, and reduce competitiveness in hybrid poplar.

    Science.gov (United States)

    Elias, Ani A; Busov, Victor B; Kosola, Kevin R; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W; Rood, Stewart B; Strauss, Steven H

    2012-10-01

    Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA(20) and GA(8), in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations.

  12. Political Competitiveness

    OpenAIRE

    Casey B. Mulligan; Kevin K. Tsui

    2006-01-01

    Political competitiveness - which many interpret as the degree of democracy - can be modeled as a monopolistic competition. All regimes are constrained by the threat of "entry," and thereby seek some combination of popular support and political entry barriers. This simple model predicts that many public policies are unrelated to political competitiveness, and that even unchallenged nondemocratic regimes should tax far short of their Laffer curve maximum. Economic sanctions, odious debt repudi...

  13. On the origin of sperm epigenetic heterogeneity.

    Science.gov (United States)

    Laurentino, Sandra; Borgmann, Jennifer; Gromoll, Jörg

    2016-05-01

    The influence of epigenetic modifications on reproduction and on the function of male germ cells has been thoroughly demonstrated. In particular, aberrant DNA methylation levels in sperm have been associated with abnormal sperm parameters, lower fertilization rates and impaired embryo development. Recent reports have indicated that human sperm might be epigenetically heterogeneous and that abnormal DNA methylation levels found in the sperm of infertile men could be due to the presence of sperm populations with different epigenetic quality. However, the origin and the contribution of different germ cell types to this suspected heterogeneity remain unclear. In this review, we focus on sperm epigenetics at the DNA methylation level and its importance in reproduction. We take into account the latest developments and hypotheses concerning the functional significance of epigenetic heterogeneity coming from the field of stem cell and cancer biology and discuss the potential importance and consequences of sperm epigenetic heterogeneity for reproduction, male (in)fertility and assisted reproductive technologies (ART). Based on the current information, we propose a model in which spermatogonial stem cell variability, either intrinsic or due to external factors (such as endocrine action and environmental stimuli), can lead to epigenetic sperm heterogeneity, sperm epimutations and male infertility. The elucidation of the precise causes for epimutations, the conception of adequate therapeutic options and the development of sperm selection technologies based on epigenetic quality should be regarded as crucial to the improvement of ART outcome in the near future. © 2016 Society for Reproduction and Fertility.

  14. Pop competitiveness

    OpenAIRE

    Roberto Cellino; Anna Soci

    2002-01-01

    Very few economic terms are used as much as competitiveness in economics. This article deals with the different meanings of competitiveness, at the level of a firm, at the level of the local area, and at the level of the country. It analyzes the problems of consistency among the available definitions and among the indicators used to measurecompetitiveness.

  15. Competitiveness factors

    OpenAIRE

    Popa Liliana-Viorica

    2012-01-01

    Porter's theory supports the idea that, despite the globalization of production and trade, the competitive advantage is created in a national framework, nations, through their institutional, natural, cultural, economic characteristics ultimately determining the development of certain economic activities. The factors considered by Porter as determinants for the competitive advantage are grouped in four categories, the linkages between them being important as well

  16. Temporal trends in sperm count

    DEFF Research Database (Denmark)

    Levine, Hagai; Jørgensen, Niels; Martino-Andrade, Anderson

    2017-01-01

    , method of measuring SC and semen volume, exclusion criteria and indicators of completeness of covariate data]. The slopes of SC and TSC were estimated as functions of sample collection year using both simple linear regression and weighted meta-regression models and the latter were adjusted for pre......-determined covariates and modification by fertility and geographic group. Assumptions were examined using multiple sensitivity analyses and nonlinear models. OUTCOMES: SC declined significantly between 1973 and 2011 (slope in unadjusted simple regression models -0.70 million/ml/year; 95% CI: -0.72 to -0.69; P ...BACKGROUND: Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality. OBJECTIVE AND RATIONALE: To provide a systematic review and meta-regression...

  17. Chemotactic movement in sperm of the oogamous brown algae, Saccharina japonica and Fucus distichus.

    Science.gov (United States)

    Kinoshita, Nana; Nagasato, Chikako; Motomura, Taizo

    2017-01-01

    In oogamous species of brown algae such as Saccharina japonica and Fucus distichus, the sperm possess an unusual long posterior flagellum, which oscillates actively and produces a propulsive force during swimming. In this study, we quantitatively analyzed the effect of chemotactic responses on sperm swimming and flagellar waveforms by high-speed video recordings. We found that the thigmotactic response to the chemo-attractant was not enhanced during chemotactic swimming and that the swimming velocity of sperm did not decrease. As concentration of the chemo-attractant decreased, the sperm performed drastic U-turn movements, which was caused by a rapid and large bend of the posterior flagellum. Unilateral bending of the posterior flagellum when sensing a decrease in the concentration of the chemo-attractant may be a common response in male gametes during fertilization of brown algae both oogamous and isogamous species.

  18. Enhancement of High-Intensity Actions and Physical Performance During a Simulated Brazilian Jiu-Jitsu Competition With a Moderate Dose of Caffeine.

    Science.gov (United States)

    Diaz-Lara, Francisco Javier; Del Coso, Juan; Portillo, Javier; Areces, Francisco; García, Jose Manuel; Abián-Vicén, Javier

    2016-10-01

    Although caffeine is one of the most commonly used substances in combat sports, information about its ergogenic effects on these disciplines is very limited. To determine the effectiveness of ingesting a moderate dose of caffeine to enhance overall performance during a simulated Brazilian jiu-jitsu (BJJ) competition. Fourteen elite BJJ athletes participated in a double-blind, placebo-controlled experimental design. In a random order, the athletes ingested either 3 mg/kg body mass of caffeine or a placebo (cellulose, 0 mg/kg) and performed 2 simulated BJJ combats (with 20 min rest between them), following official BJJ rules. Specific physical tests such as maximal handgrip dynamometry, maximal height during a countermovement jump, permanence during a maximal static-lift test, peak power in a bench-press exercise, and blood lactate concentration were measured at 3 specific times: before the first combat and immediately after the first and second combats. The combats were video-recorded to analyze fight actions. After the caffeine ingestion, participants spent more time in offensive actions in both combats and revealed higher blood lactate values (P Performance in all physical tests carried out before the first combat was enhanced with caffeine (P caffeine and placebo. Caffeine might be an effective ergogenic aid for improving intensity and physical performance during successive elite BJJ combats.

  19. Nuclear microscopy of sperm cell elemental structure

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G.S.; Balhorn, R.; Friz, A.M.; Freeman, S.P.H.T.

    1994-09-28

    Theories suggest there is a link between protamine concentrations in individual sperm and male fertility. Previously, biochemical analyses have used pooled samples containing millions of sperm to determine protamine concentrations. These methods have not been able to determine what percentage of morphologically normal sperm are biochemically defective and potentially infertile. Nuclear microscopy has been utilized to measure elemental profiles at the single sperm level. By measuring the amount of phosphorus and sulfur, the total DNA and protamine content in individual sperm from fertile bull and mouse semen have been determined. These values agree with results obtained from other biochemical analyses. Nuclear microscopy shows promise for measuring elemental profiles in the chromatin of individual sperm. The technique may be able to resolve theories regarding the importance of protamines to male fertility and identify biochemical defects responsible for certain types of male infertility.

  20. Sperm interaction with the female reproductive tract.

    Science.gov (United States)

    Druart, X

    2012-08-01

    Sperm transit in the female tract is a critical event for the success of fertilization. From their deposition in the vagina to final migration in the oviduct, sperm pass through the different compartments of the genital tract in which they encounter different environments. The cervix and the uterotubal junction (UTJ) are two barriers with different relative importance according to the species. The protein composition, the degree of glycosylation and the hydration of the cervical mucus change during the oestrous cycle. Several sperm surface proteins are associated with their migration through the cervical mucus and the UTJ. Data regarding the interaction of sperm with secretions of the epithelial tissue lining the different compartments of the female genital tract during the sperm transit are reviewed, with a particular emphasis on the migration of sperm through the cervix. © 2012 Blackwell Verlag GmbH.

  1. Problems of enhancing the competitiveness of the dairy sector in a developing economy at the time of economic integration into the European Union

    OpenAIRE

    Karpavičius, Henrikas

    2004-01-01

    The study is aimed at highlighting the importance of competitive advantage and methods for the national diary industry with Lithuanian joining the EU and becoming a member of a huge common market. Pursuant to the provisions of the Porter’s Theory of Competitive Advantage, factors defining tendencies in the dynamics of the level of competitiveness are divided into two groups: 1. factors influencing competitive stimuli within the industry (possible impact of suppliers of raw milk; increasing co...

  2. Swedish sperm donors are driven by altruism, but shortage of sperm donors leads to reproductive travelling.

    Science.gov (United States)

    Ekerhovd, Erling; Faurskov, Anders; Werner, Charlotte

    2008-01-01

    Swedish legislation requires that sperm donors are identifiable to offspring. In Denmark sperm donors remain anonymous. The aim of this study was to examine sperm donation in Sweden by identifying socio-demographic backgrounds, motivations and attitudes among donors and to describe options and plans of sperm recipients. Furthermore, the willingness of Swedish health care providers to assist in treatment abroad, where sperm from an anonymous donor were to be used, was assessed. The extent of travelling to Denmark for reproductive purposes was also examined. Thirty Swedish sperm donors completed a questionnaire and were interviewed about their backgrounds, motivations and attitudes. Thirty couples where the infertility workup had shown azoospermia were interviewed about their options for achieving parenthood. The willingness to assist in fertility treatment abroad and the extent of reproductive cross border travelling were assessed by interviewing health care providers and by contacting Danish clinics. Almost all donors were Caucasian. The main motivation for sperm donors was to help others. Owing to shortage of sperm donors many Caucasian recipients intended to have treatment abroad. For most non-Caucasian recipients sperm from a donor of appropriate ethnicity were not available in Sweden. Whether the sperm donor was anonymous or identifiable was not of major importance to most sperm recipients. Health care providers expressed unanimous willingness to assist in treatment with sperm from an anonymous donor. Our inquiry indicated that more than 250 Swedish sperm recipients travel to Denmark annually. Identifiable sperm donors are driven by altruistic motives, but shortage of sperm donors leads to reproductive travelling. Recruitment strategies to increase the number of sperm donors in Sweden are therefore warranted.

  3. Ejaculated mouse sperm enter cumulus-oocyte complexes more efficiently in vitro than epididymal sperm.

    Science.gov (United States)

    Li, Honggang; Hung, Pei-Hsuan; Suarez, Susan S

    2015-01-01

    The mouse is an established and popular animal model for studying reproductive biology. Epididymal mouse sperm, which lack exposure to secretions of male accessory glands and do not precisely represent ejaculated sperm for the study of sperm functions, have been almost exclusively used in studies. We compared ejaculated and epididymal sperm in an in vitro fertilization setting to examine whether ejaculated sperm enter cumulus-oocyte complexes more efficiently. In order to prepare sperm for fertilization, they were incubated under capacitating conditions. At the outset of incubation, ejaculated sperm stuck to the glass surfaces of slides and the incidences of sticking decreased with time; whereas, very few epididymal sperm stuck to glass at any time point, indicating differences in surface charge. At the end of the capacitating incubation, when sperm were added to cumulus-oocyte complexes, the form of flagellar movement differed dramatically; specifically, ejaculated sperm predominantly exhibited increased bending on one side of the flagellum (a process termed pro-hook hyperactivation), while epididymal sperm equally exhibited increased bending on one or the other side of the flagellum (pro-hook or anti-hook hyperactivation). This indicates that accessory sex gland secretions might have modified Ca2+ signaling activities in sperm, because the two forms of hyperactivation are reported to be triggered by different Ca2+ signaling patterns. Lastly, over time, more ejaculated than epididymal sperm entered the cumulus oocyte complexes. We concluded that modification of sperm by male accessory gland secretions affects the behavior of ejaculated sperm, possibly providing them with an advantage over epididymal sperm for reaching the eggs in vivo.

  4. COMPETITIVENESS FOR SUSTAINABLE ECONOMIES

    Directory of Open Access Journals (Sweden)

    Nelu Eugen POPESCU

    2014-04-01

    Full Text Available The current economic environment puts pressure on all national economies which struggle to improve their competitiveness and innovativeness in a sustainable way. This article aims to present the current state of the competitiveness by reviewing the main literature and worldwide researches, in order to provide a brief overview of the determinants that drive productivity and economic success at global and national level, taking into consideration the entrepreneurial activity for a country’s competitiveness and economic growth. The paper identifies the ways in which efficiency driven countries can improve their policies and get a better return on their investments, underlining a set of competitiveness enhancing policies (measures that can be implemented by public and private institutions in order to strengthen the economic fundamentals of the economies.

  5. Strategies to enhance the competitiveness of semi-intensive aquaculture systems in costal earth ponds: the organic aquaculture approach

    Directory of Open Access Journals (Sweden)

    Manuel Sardinha

    2014-06-01

    Full Text Available Earthen ponds are the main production system for European seabass (Dicentrarchus labrax and gilthead seabream (Sparus aurata in Portugal and in Southern Spain. Production costs in this low productivity farming system are higher compared to intensive cage farms, and its economic sustainability depends on product differentiation and optimization of production. The development of new farming protocols, to enhance productivity of ponds and lagoons, or the implementation of certification processes to add value to products from extensive and semi-intensive systems, could render these activities more economics benefits and be attractive for a new generation of farmers. One clear strategy to differentiate and add value to seabream produced in semi-intensive systems is its production under organic standards. Feeds often represent 40-60% of the operational costs of fish farming. In relation to the traditional feeds, the organic certified feeds currently present a price-differential of about +30%. To assess it economic feasibility, it is therefore essential to validate if such higher feeding costs will represent an increase on productivity (fish growth and feed conversion or can be fully integrated in the final sale price. Throughout a full production cycle of gilthead seabream (from 9 grams until >350 grams, a series of trials allowed us to assess the effects of: a an organic certified feed; b variable feeding levels (100 and 80% of recommendations; and c culture density (0.5 and 1.0 kg/m3 on the overall growth performance, body composition and environmental impact at the fish farm level. Results show that growth performance (weight gain and feed conversion ratio of seabream fed the organic feed was similar to that found in fish fed a traditional diet. With the organic feed, a reduction of the feeding level by 20% of the manufacturer recommendations led to a lower growth, while a similar reduction on the feeding level of the traditional feed had no impact

  6. Is Cunnilingus-Assisted Orgasm a Male Sperm-Retention Strategy?

    Directory of Open Access Journals (Sweden)

    Michael N. Pham

    2013-04-01

    Full Text Available We secured data from 243 men in committed, sexual, heterosexual relationships to test the sperm retention hypothesis of oral sex. We predicted that, among men who perform cunnilingus on their partner, those at greater risk of sperm competition are more likely to perform cunnilingus until their partner achieves orgasm (Prediction 1, and that, among men who ejaculate during penile-vaginal intercourse and whose partner experiences a cunnilingus-assisted orgasm, ejaculation will occur during the brief period in which female orgasm might function to retain sperm (Prediction 2. The results support Prediction 1 but not Prediction 2. We discuss limitations of the current research and discuss how these results may be more consistent with alternative hypotheses regarding female orgasm and oral sex.

  7. Role of nitric oxide in motility and fertilizing ability of sperm of Heteropneustes fossilis (Bloch.).

    Science.gov (United States)

    Barman, A S; Kumar, Pankaj; Mariahabib; Lal, K K; Lal, Bechan

    2013-02-01

    The presence of neuronal nitric oxide synthase (nNOS), inducible NOS (iNOS) and nitric oxide (NO) in the testis of seasonally breeding catfish has previously been demonstrated. The present study was aimed to investigate the presence of NO in fish gametes and its role in sperm physiology and strengthen the previous findings. NO, a biological signalling molecule is synthesized during the conversion of l-arginine to l-citrulline by nitric oxide synthases (NOS) in the presence of NADPH and oxygen. In the present study, a considerable amount of NO content was detected in the fresh sperm suspension of fish. A drastic reduction in NO content of the sperm suspension was observed after cryopreservation. Ovarian fluid collected from freshly stripped eggs also contained a substantial amount of NO. Further, effects of a NO donor, sodium nitroprusside (SNP), and NOS inhibitor, N-(G)-nitro-l-arginine-methyl ester (l-NAME) were evaluated on motility and fertilizing ability of fresh and cryopreserved sperm. The percentage of motile fresh sperm (66.2±3.7%) was enhanced (P<0.05) by SNP at the dose of 10(-3)M, whereas the greater and lesser concentrations of SNP did not influence the percentage of motility as compared to the control. However, a significant reduction in the percentage of motile fresh sperm was observed at the tested doses of 10(-3)M and 10(-4)M of l-NAME. The maximum reduction (23.0±3.4%) was evoked at the greatest concentration (10(-3)M); while at the smallest dose of 10(-5)M, reduction was insignificant. Ovarian fluid also enhanced sperm motility. Altogether, findings of the present study suggest that NO plays an important role in sperm performance of fish. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Artificial insemination with donor sperm (AID): heterogeneity in sperm banking facilities in a single country (Belgium)

    Science.gov (United States)

    Thijssen, A.; Dhont, N.; Vandormael, E.; Cox, A.; Klerkx, E.; Creemers, E.; Ombelet, W.

    2014-01-01

    Due to the high inflow of foreign patients seeking cross-border reproductive care in Belgium and the increased number of lesbian couples and single women who call for artificial insemination with donor sperm (AID), Belgian sperm banks nowadays face a shortage in donor sperm. However, since there is no central registration system for sperm donors in Belgium, no figures are currently available supporting this statement. Therefore a study was performed to obtain a detailed overview of the sperm banking facilities in Belgium. Questionnaires were sent to all Belgian centres for assisted reproduction with laboratory facilities (n = 18) to report on their sperm banking methods. The results showed that 82% of the centres rely partially or completely on foreign donor sperm. Moreover, four of the thirteen centres that have their own sperm bank use imported donor sperm in > 95% AID cycles. Our results show that in 63% of the Belgian AID cycles imported Danish donor sperm is being used. Donor recruitment is mainly performed through the centre’s website (61%) or by distributing flyers in the centre (46%) and 9 to 180 potential donors have been recruited per centre in 2013. Eventually, 15 to 50% of these candidate donors were accepted. Different criteria for donor acceptance are handled by the centres: donor age limits range from 18-25 to 36-46 years old, and thresholds for sperm normality differ considerably. We can conclude that a wide variation in methods associated with sperm banking is observed in Belgian centres. PMID:25009728

  9. Sperm cryopreservation update: Cryodamage, markers, and factors affecting the sperm freezability in pigs.

    Science.gov (United States)

    Yeste, Marc

    2016-01-01

    Cryopreservation is the most efficient method for long-term preservation of mammalian sperm. However, freeze-thawing procedures may strongly impair the sperm function and survival and thus decrease the reproductive performance. In addition, the sperm resilience to withstand cryopreservation, also known as freezability, presents a high individual variability. The present work summarizes the principles of cryoinjury and the relevance of permeating and nonpermeating cryoprotective agents. Descriptions about sperm cryodamage are mainly focused on boar sperm, but reference to other mammalian species is also made when relevant. Main cryoinjuries not only regard to sperm motility and membrane integrity, but also to the degradation effect exerted by freeze-thawing on other important components for sperm fertilizing ability, such as mRNAs. After delving into the main differences between good and poor freezability boar ejaculates, those protein markers predicting the sperm ability to sustain cryopreservation are also mentioned. Moreover, factors that may influence sperm freezability, such as season, diet, breed, or ejaculate fractions are discussed, together with the effects of different additives, like seminal plasma and antioxidants. After briefly referring to the effects of long-term sperm preservation in frozen state and the reproductive performance of frozen-thawed boar sperm, this work speculates with new research horizons on the preservation of boar sperm, such as vitrification and freeze-drying. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Impact of dietary fatty acids on muscle composition, liver lipids, milt composition and sperm performance in European eel

    DEFF Research Database (Denmark)

    Butts, Ian; Baeza, R.; Støttrup, Josianne

    2015-01-01

    of dietary regime on muscle composition, and liver lipids prior to induced maturation, and the resulting sperm composition and performance. To accomplish this fish were reared on three "enhanced" diets and one commercial diet, each with different levels of fatty acids, arachidonic acid (ARA......), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Neutral lipids from the muscle and liver incorporated the majority of the fatty acid profile, while phospholipids incorporated only certain fatty acids. Diet had an effect on the majority of sperm fatty acids, on the total volume of extractable milt...... induced medium milt volumes but had the highest sperm motility. EPA also seems important for sperm quality parameters since diets with higher EPA percentages had a higher volume of milt and higher sperm motility. In conclusion, dietary fatty acids had an influence on fatty acids in the tissues of male eel...

  11. Seminal fluid from men with agenesis of the Wolffian ducts: zinc-binding properties and effects on sperm chromatin stability.

    Science.gov (United States)

    Kvist, U; Kjellberg, S; Björndahl, L; Soufir, J C; Arver, S

    1990-08-01

    Zinc-binding properties were studied in 'prostatic fluid', i.e. in seminal plasma from patients with agenesis of the Wolffian ducts, and in split-ejaculate fractions dominated by seminal vesicular fluid. The effect of seminal fluid, with different zinc-binding properties, on the stability of zinc-dependent sperm chromatin was assessed by exposing sperm to 1% sodium dodecyl sulphate (SDS) for 60 min. Citrate was the only zinc ligand in 'prostatic fluid', as revealed by gel chromatography. Zinc in this fluid enhanced the stability of sperm chromatin. In contrast, the stability of sperm chromatin was decreased in seminal plasma dominated by vesicular fluid. These results are in accordance with the concept that prostatic fluid ensures the appropriate zinc content and stability of sperm chromatin, whereas abundance of vesicular fluid may jeopardize chromatin stability by reducing chromatin zinc content.

  12. Reflections on Competition, Competition Regulation and the Current Crises

    DEFF Research Database (Denmark)

    Buch-Hansen, Hubert; Wigger, Angela

    2013-01-01

    Economists, politicians, business leaders and opinion makers are convinced that competition enhances efficiency and maximises social welfare. As a result conditions conducive to the maximisation of competition have been created throughout developed capitalist societies. This article explains how...... crises currently facing humanity. The implication of the argument is that these crises can only be solved if prevailing notions of competition and its role in society are reconsidered....

  13. Varicocele Negatively Affects Sperm Mitochondrial Respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Albani, Denise; Coppola, Lamberto; Zara, Vincenzo

    2015-10-01

    To evaluate the effect of varicocele on oxidative stress, sperm mitochondrial respiratory efficiency, sperm morphology, and semen parameters. A total of 20 patients with varicocele and 20 normozoospermic subjects without varicocele (control group) were recruited from a medical center for reproductive biology. The levels of serum reactive oxygen metabolites and seminal lipid peroxides were assessed for both control and varicocele subjects. Sperm deoxyribonucleic acid fragmentation was measured by sperm chromatin dispersion test. Mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. In this study, varicocele patients were compared with men without varicoceles. Oxidative stress was observed in the serum and seminal fluid of varicocele patients. These patients showed an increase of 59% (P <.05) in serum reactive oxygen metabolites and a 3-fold increase in the level of sperm lipid peroxides. A parallel and significant increase (a 2-fold increase; P <.05) in the degree of sperm deoxyribonucleic acid fragmentation was also observed. Varicocele patients showed a 27% decrease (P <.05) in mitochondrial respiratory activity in comparison to the control group. A 32% increase (P <.05) in sperm midpiece defects and a 41% decrease (P <.05) in sperm concentration and motility were also observed. Men with varicocele have increased markers of oxidative stress and decreased mitochondrial respiratory activity. These results correlated with abnormalities in semen parameters. For morphology, these correlated with midpiece defects. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Hypercholesterolemia Impaired Sperm Functionality in Rabbits

    Science.gov (United States)

    Monclus, Maria A.; Cabrillana, Maria E.; Clementi, Marisa A.; Espínola, Leandro S.; Cid Barría, Jose L.; Vincenti, Amanda E.; Santi, Analia G.; Fornés, Miguel W.

    2010-01-01

    Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events. PMID:20976152

  15. Current status and potential of morphometric sperm analysis

    OpenAIRE

    Maroto-Morales, Alejandro; García-Álvarez, Olga; Ramón, Manuel; Martínez-Pastor, Felipe; Fernández-Santos, M. Rocío; Soler, Ana J.; Garde, José Julián

    2016-01-01

    The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cr...

  16. Single blastocyst transfer after ICSI from ejaculate spermatozoa, percutaneous epididymal sperm aspiration (PESA) or testicular sperm extraction (TESE)

    OpenAIRE

    Nilsson, Staffan; Waldenström, Urban; Engström, Ann-Britt; Hellberg, Dan

    2007-01-01

    Purpose: To investigate the outcome of IVF following intracytoplasmic sperm injection (ICSI) from ejaculate, percutaneous epididymal sperm aspiration (PESA) and testicular sperm extraction (TESE), with subsequent blastocyst culture and single blastocyst transfer.

  17. Current status and potential of morphometric sperm analysis

    Directory of Open Access Journals (Sweden)

    Alejandro Maroto-Morales

    2016-01-01

    Full Text Available The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cryoresistance and male fertility is also discussed. For this, the evaluation of patterns of change of sperm head morphometry throughout a process, instead of the study of the morphometric characteristics of the sperm head at different stages, allows a better identification of the males with different sperm cryoconservation ability. These new approaches, together with more studies employing a greater number of individuals, are needed to obtain novel results concerning the role of sperm morphometry on sperm function. Future studies should aim at understanding the causes of sperm design diversity and the mechanisms that generate them, giving increased attention to other sperm structures besides the sperm head. The implementation of scientific and technological advances could benefit the simultaneous examination of sperm phenotype and sperm function, demonstrating that sperm morphometry could be a useful tool for sperm assessment.

  18. Current status and potential of morphometric sperm analysis.

    Science.gov (United States)

    Maroto-Morales, Alejandro; García-Álvarez, Olga; Ramón, Manuel; Martínez-Pastor, Felipe; Fernández-Santos, M Rocío; Soler, A Josefa; Garde, José Julián

    2016-01-01

    The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cryoresistance and male fertility is also discussed. For this, the evaluation of patterns of change of sperm head morphometry throughout a process, instead of the study of the morphometric characteristics of the sperm head at different stages, allows a better identification of the males with different sperm cryoconservation ability. These new approaches, together with more studies employing a greater number of individuals, are needed to obtain novel results concerning the role of sperm morphometry on sperm function. Future studies should aim at understanding the causes of sperm design diversity and the mechanisms that generate them, giving increased attention to other sperm structures besides the sperm head. The implementation of scientific and technological advances could benefit the simultaneous examination of sperm phenotype and sperm function, demonstrating that sperm morphometry could be a useful tool for sperm assessment.

  19. Coal competitiveness?

    International Nuclear Information System (INIS)

    Rogeaux, B.

    2006-01-01

    Will coal electrical plants be more competitive in the coming years? Answering this one cannot be limited to merely comparing estimates based on reference electricity production costs. The competitiveness of coal will indeed depend on the final product marketed, as the MWhs are not equal: is the purpose to produce base, half-base MWh? Does the electrical equipment structure require flexible MWh (for instance in the event of significant intermittent renewable energy amounts), and therefore plants able to adjust their power rapidly? But the competitiveness of coal will also depend on many factors that will correct reference cost estimates: uncertainties, risks, externalities. These factors will need to be appreciated on a case by case basis. We introduce some of the reasoning used to better appreciate the future competitiveness of coal, and the main factors conditioning it in three contrasting regions of the world: Europe, USA, china. (author)

  20. Understanding competitiveness

    OpenAIRE

    CRESPO, Aranzazu; SEGURA-CAYUELA, Ruben

    2014-01-01

    Using firm level data, we analyze the factors that drive the evolution of the aggregate Unit Labor Costs – the main European competitiveness indicator – in France, Germany, Italy and Spain. The evolution of the aggregate Unit Labor Cost is not driven by the evolution of the firm level Unit Labor Costs, but rather by an important factor for the competitiveness of a country: the reallocation of resources among the firms of the economy. Using the methodology of Hsieh and Klenow (...

  1. REGIONAL COMPETITIVENESS

    OpenAIRE

    Krželj-Čolović, Zorica

    2015-01-01

    Individual city and regional authorities in many countries have themselves taken up the issue of “competitiveness” as part of their own economic development agendas: competitiveness has come to be regarded as critical for understanding and promoting local economic performance. Like their national counterparts, regional and city policy-makers have become preoccupied with knowing the relative competitive standing of their local economies compared with others, not just other regions and cities w...

  2. Directional postcopulatory sexual selection is associated with female sperm storage in Trinidadian guppies.

    Science.gov (United States)

    Devigili, Alessandro; Di Nisio, Andrea; Grapputo, Alessandro; Pilastro, Andrea

    2016-08-01

    Female sperm storage (FSS) is taxonomically widespread and often associated with intense sperm competition, yet its consequences on postcopulatory sexual selection (PCSS) are poorly known. Theory predicts that FSS will reduce the strength of PCSS, because sperm characteristics favored before and after FSS may be traded-off, and opportunities for nondirectional PCSS should increase. We explored these questions in the guppy (Poecilia reticulata), by allowing females to mate multiply and by comparing the paternity pattern in two successive broods. Contrary to predictions, the variance in male fertilization success increased after FSS, driven by a change in male paternity share across broods. This change was positively associated with sperm velocity (measured before FSS) but not with the duration of FSS, indirectly suggesting that faster sperm were better in entering female storage organs, rather than in persisting within them. Other male traits, such as male size and orange color, heterozygosity, and relatedness to the female, did not influence paternity after FSS. These results indicate that processes associated with FSS tend to reinforce the strength of PCSS in guppies, rather than weaken it. Further work is necessary to test whether this pattern changes in case of more prolonged FSS. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  3. Observation of sperm-head vacuoles and sperm morphology under light microscope.

    Science.gov (United States)

    Park, Yong-Seog; Park, Sol; Ko, Duck Sung; Park, Dong Wook; Seo, Ju Tae; Yang, Kwang Moon

    2014-09-01

    The presence of sperm-head vacuoles has been suspected to be deleterious to the outcomes of assisted reproductive technology (ART). It is difficult to accurately distinguish morphologically abnormal sperm with vacuoles under a light microscope. This study was performed to analyze the result of the observation of sperm-head vacuoles using Papanicolaou staining under a light microscope and whether the male partner's age affects these vacuoles. Sperm morphology with vacuoles was evaluated using Papanicolaou staining and observed under a light microscope (400×) in 980 men. The normal morphology was divided into three categories (group A, 14% of normal morphology). The criteria for the sperm-head vacuoles were those given in the World Health Organization manual. For the analysis of the age factor, the participants were divided into the following groups: 26-30 years, 31-35 years, 36-40 years, 41-45 years, and 46-50 years. The percentage of sperm-head vacuoles increased with normal sperm morphology (group A vs. groups B, C) (p<0.05). In the case of the age factor, a statistically significant difference was not observed across any of the age groups. A majority of the sperm-head vacuoles showed a statistically significant difference among normal morphology groups. Therefore, we should consider the probability of the percentage of sperm-head vacuoles not increasing with age but with abnormal sperm morphology. A further study is required to clarify the effect of the sperm-head vacuoles on ART outcomes.

  4. Mitochondrial respiratory efficiency is positively correlated with human sperm motility.

    Science.gov (United States)

    Ferramosca, Alessandra; Provenzano, Sara Pinto; Coppola, Lamberto; Zara, Vincenzo

    2012-04-01

    To correlate sperm mitochondrial respiratory efficiency with variations in sperm motility and with sperm morphologic anomalies. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically-treated sperm cells. A possible relationship among sperm mitochondrial respiratory efficiency, sperm motility, and morphologic anomalies was investigated. Mitochondrial respiratory efficiency was positively correlated with sperm motility and negatively correlated with the percentage of immotile spermatozoa. Moreover, midpiece defects impaired mitochondrial functionality. Our data indicate that an increase in sperm motility requires a parallel increase in mitochondrial respiratory capacity, thereby supporting the fundamental role played by mitochondrial oxidative phosphorylation in sperm motility of normozoospermic subjects. These results are of physiopathological relevance because they suggest that disturbances of sperm mitochondrial function and of energy production could be responsible for asthenozoospermia. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Mitochondrial PKA mediates sperm motility.

    Science.gov (United States)

    Mizrahi, Rashel; Breitbart, Haim

    2014-12-01

    Mitochondria are the major source of ATP to power sperm motility. Phosphorylation of mitochondrial proteins has been proposed as a major regulatory mechanism for mitochondrial bioenergetics. Sperm motility was measured by a computer-assisted analyzer, protein detection by western blotting, membrane potential by tetramethylrhodamine, cellular ATP by luciferase assay and localization of PKA by immuno-electron microscopy. Bicarbonate is essential for the creation of mitochondrial electro-chemical gradient, ATP synthesis and sperm motility. Bicarbonate stimulates PKA-dependent phosphorylation of two 60kDa proteins identified as Tektin and glucose-6-phosphate isomerase. This phosphorylation was inhibited by respiration inhibition and phosphorylation could be restored by glucose in the presence of bicarbonate. However, this effect of glucose cannot be seen when the mitochondrial ATP/ADP exchanger was inhibited indicating that glycolytic-produced ATP is transported into the mitochondria and allows PKA-dependent protein phosphorylation inside the mitochondria. Bicarbonate activates mitochondrial soluble adenylyl cyclase (sAC) which catalyzes cAMP production leading to the activation of mitochondrial PKA. Glucose can overcome the lack of ATP in the absence of bicarbonate but it cannot affect the mitochondrial sAC/PKA system, therefore the PKA-dependent phosphorylation of the 60kDa proteins does not occur in the absence of bicarbonate. Production of CO2 in Krebs cycle, which is converted to bicarbonate is essential for sAC/PKA activation leading to mitochondrial membrane potential creation and ATP synthesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Children conceived after intracytoplasmic sperm injection (ICSI)

    DEFF Research Database (Denmark)

    Mau, C; Juul, A; Main, K M

    2004-01-01

    The aim of the study was to evaluate current medical knowledge about children born after intracytoplasmic sperm injection (ICSI) with respect to congenital malformations, chromosome abnormalities and postnatal growth.......The aim of the study was to evaluate current medical knowledge about children born after intracytoplasmic sperm injection (ICSI) with respect to congenital malformations, chromosome abnormalities and postnatal growth....

  7. Short communication Relationship between sperm plasma ...

    African Journals Online (AJOL)

    Matshidiso MB. Masenya

    2017-01-04

    Jan 4, 2017 ... Abstract. Sperm quality plays an important role in determining fertility. The aim of the study was to examine the relationship between sperm plasma membrane integrity and morphology, and fertility following artificial insemination (AI). A total of 16 ejaculates were collected from three Large White boars using ...

  8. Relationship between sperm plasma membrane integrity and ...

    African Journals Online (AJOL)

    Sperm quality plays an important role in determining fertility. The aim of the study was to examine the relationship between sperm plasma membrane integrity and morphology, and fertility following artificial insemination (AI). A total of 16 ejaculates were collected from three Large White boars using the gloved hand ...

  9. Testicular Damage following Testicular Sperm Retrieval

    DEFF Research Database (Denmark)

    Fedder, Jens; Marcussen, Niels; Fedder, Maja D.K.

    2017-01-01

    The aim of this study was to evaluate the possible development of histological abnormalities such as fibrosis and microcalcifications after sperm retrieval in a ram model. Fourteen testicles in nine rams were exposed to open biopsy, multiple TESAs, or TESE, and the remaining four testicles were...... left unoperated on as controls. Three months after sperm retrieval, the testicles were removed, fixed, and cut into 1/2 cm thick slices and systematically put onto a glass plate exposing macroscopic abnormalities. Tissue from abnormal areas was cut into 3 μm sections and stained for histological...... evaluation. Pathological abnormalities were observed in testicles exposed to sperm retrieval (≥11 of 14) compared to 0 of 4 control testicles. Testicular damage was found independently of the kind of intervention used. Therefore, cryopreservation of excess sperm should be considered while retrieving sperm....

  10. BMI in relation to sperm count

    DEFF Research Database (Denmark)

    Sermondade, N; Faure, C; Fezeu, L

    2013-01-01

    BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review...... with meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men...... studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm...

  11. La compétition spermatique chez les insectes: les stratégies d'assurance de la paternité et la préséance du sperme

    Directory of Open Access Journals (Sweden)

    Arnaud L.

    1999-01-01

    Full Text Available Sperm competition in insects: paternity assurance and sperm precedence. The prediction that insects, as a result of polyandry, extreme sperm longevity within the female and high efficiency of sperm utilisation at fertilisation, are preadapted to sustain a very high level of sperm competition is demonstrated across numerous studies. In many insects, males have evolved strategies to decrease sperm competition risk. Paternity assurance mechanisms such as mating plugs or mate guarding do not necessarily influence the number of eggs laid by the female but are taken by male to reduce the probability of his sperm to be preceded by the sperm of another male. Each of these mechanisms influencing mating has an adaptative significance in promoting male reproductive success. However, female insects are polyandrous and they play an active role in mate choice and in discrimination between the ejaculates of different males. Also, they have co-evolved strategy to increase their own reproductive success and to counteract the costs resulting from paternity assurance mechanisms. They can control paternity before copulation (pre-copulation, pre-insemination, during copulation, and because fertilisation takes place within their bodies after insemination, and after fertilisation through selective abortion. A male's reproductive success can be determined as the product of his mating success (mate per lifetime and his fertilisation success (average number of progeny sired per mate. Male fertilisation success is generally studied in terms of sperm precedence where the proportion of the female progeny fathered by a given male is examined. Sperm precedence can be studied using different methods, each having advantages and disadvantages. Although female insects behave polyandrously, most sperm competition studies investigate sperm precedence when only two males are mated with a female. To determine if the results obtained in double-mating experiments fit well with reality

  12. CONCEPTUAL APPROACH OF COMPETITIVENESS AND INTERDEPENDENCE BETWEEN COMPETITION AND COMPETITIVENESS

    Directory of Open Access Journals (Sweden)

    Tatiana GUTIUM

    2017-11-01

    Full Text Available This article is devoted to analysis of interdependence and correlation between competition and competitiveness, and competition’s consequences. The author analysed some authors’ visions on competitiveness, and common features between theories of competition and competitiveness. Using the synthetic indicator elaborated by author has been evaluated the competitiveness of domestic goods on the internal and external market. At the end of this article, the author has developed proposals to increase competitiveness.

  13. Role of Human Na,K-ATPase alpha 4 in Sperm Function, Derived from Studies in Transgenic Mice

    Science.gov (United States)

    McDermott, Jeffrey; Sánchez, Gladis; Nangia, Ajay K.; Blanco, Gustavo

    2014-01-01

    SUMMARY Most of our knowledge on the biological role of the testis-specific Na,K-ATPase alpha 4 isoform derives from studies performed in non-human species. Here, we studied the function of human Na,K-ATPase alpha 4 after its expression in transgenic mice. Using a bacterial artificial chromosome (BAC) construct, containing the human ATP1A4 gene locus, we obtained expression of the human α4 transgene specifically in mouse sperm, enriched in the sperm flagellum. The expressed, human alpha 4 was active, and compared to wild-type sperm, those from transgenic mice displayed higher Na,K-ATPase alpha 4 activity and greater binding of fluorescently labeled ouabain, which is typical of the alpha 4 isoform. The expression and activity of endogenous alpha 4 and the other Na,K-ATPase alpha isoform present in sperm, alpha 1, remained unchanged. Male mice expressing the human ATP1A4 transgene exhibited similar testis size and morphology, normal sperm number and shape, and no changes in overall fertility compared to wild-type mice. Sperm carrying the human transgene exhibited enhanced total motility and an increase in multiple parameters of sperm movement, including higher sperm hyperactive motility. In contrast, no statistically significant changes in sperm membrane potential, protein tyrosine phosphorylation, or spontaneous acrosome reaction were found between wild-type and transgenic mice. Altogether, these results provide new genetic evidence for an important role of human Na,K-ATPase alpha 4 in sperm motility and hyperactivation, and establishes a new animal model for future studies of this isoform. PMID:25640246

  14. Subcontract Competition.

    Science.gov (United States)

    1982-11-01

    DRCPM- ROL USA Missile Command, ATTN: DRCPM-VI Armor Training Devices, ATTN: DRCPM-AR 3 APRO 82-11 FINAL SUBCONTRACT COMPETITION by Wayne V. Zabel Charles...A. Correia "I S The pronouns "he," "his," and "him," when used in this publication, represent both the masculine and feminine genders unless... advertising or by negotiation, shall be made on a competitive basis to the maximum practicable extent." Armed Services Procurement Regul-tion Manual

  15. Trade-off between carotenoid-based sexual ornamentation and sperm resistance to oxidative challenge

    Czech Academy of Sciences Publication Activity Database

    Tomášek, Oldřich; Albrechtová, Jana; Němcová, M.; Opatová, Pavlína; Albrecht, Tomáš

    2017-01-01

    Roč. 284, č. 1847 (2017), č. článku 20162444. ISSN 0962-8452 R&D Projects: GA ČR(CZ) GAP506/12/2472 Institutional support: RVO:68081766 Keywords : sexual selection * phenotype-linked fertility hypothesis * sperm competition theory * ejaculate quality * lutein * zeaxanthin Subject RIV: EG - Zoology OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 4.940, year: 2016

  16. Relationship between Porcine Sperm Motility and Sperm Enzymatic Activity using Paper-based Devices

    Science.gov (United States)

    Matsuura, Koji; Huang, Han-Wei; Chen, Ming-Cheng; Chen, Yu; Cheng, Chao-Min

    2017-04-01

    Mammalian sperm motility has traditionally been analyzed to determine fertility using computer-assisted semen analysis (CASA) systems. To develop low-cost and robust male fertility diagnostics, we created a paper-based MTT assay and used it to estimate motile sperm concentration. When porcine sperm motility was inhibited using sperm enzyme inhibitors for sperm enzymes related to mitochondrial activity and glycolysis, we simultaneously recorded sperm motility and enzymatic reactivity using a portable motility analysis system (iSperm) and a paper-based MTT assay, respectively. When using our paper-based MTT-assay, we calculated the area mean value signal intensity (AMV) to evaluate enzymatic reactivity. Both sperm motility and AMV decreased following treatment with iodoacetamide (IODO) and 3-bromopyruvic acid (3BP), both of which are inhibitors of glycolytic enzymes including glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found a correlation between recorded motility using iSperm and AMV from our paper-based assay (P coupled with catalysis of GAPDH and was promoted by electron transfer from NADH. Based on this inhibitor study, sperm motility can be estimated using our paper-based MTT-assay.

  17. The influence of benign prostatic hyperplasia on sperm morphological features and sperm DNA integrity in dogs.

    Science.gov (United States)

    Flores, R B; Angrimani, Dsr; Rui, B R; Brito, M M; Abreu, R A; Vannucchi, C I

    2017-04-01

    Benign prostatic hyperplasia (BPH) has a high incidence in older intact dogs. Due to the increased prostatic oxidative stress and hormonal imbalance of BPH, sperm damage can arise, such as sperm morphological alterations and DNA fragmentation. This study aimed to compare the reproductive potential of healthy dogs and those affected by benign prostatic hyperplasia. Ten dogs were assigned to two experimental groups: dogs without BPH (control; n = 5) and dogs diagnosed with BPH (n = 5), based on clinical signs and ultrasonographic findings. Three semen collections were performed from each dog within one month and analysed using computer-assisted sperm analysis (CASA) and functional tests. Control group showed higher percentage of sperm DNA integrity (95 ± 1.8%) compared to the BPH group (79.2 ± 6.4%). On the other hand, the percentage of minor sperm defects, amplitude of lateral sperm head displacement of the spermatozoa and medium sperm mitochondrial activity were higher in the BPH group. In conclusion, BPH decreases sperm DNA integrity, increases mitochondrial activity, as well as modifies sperm movement pattern. Therefore, a careful sperm analysis of aged dogs with BPH is required before a reproductive programme can be established for such patients. © 2016 Blackwell Verlag GmbH.

  18. Competition, Efficiency, and Soundness in Banking : An Industrial Organization Perspective

    NARCIS (Netherlands)

    Schaeck, K.; Cihák, M.

    2010-01-01

    How can competition enhance bank soundness? Does competition improve soundness via the efficiency channel? Do banks heterogeneously respond to competition? To answer these questions, we exploit an innovative measure of competition [Boone, J., A new way to measure competition, EconJnl, Vol. 118, pp.

  19. Effect of calcium, bicarbonate, and albumin on capacitation-related events in equine sperm.

    Science.gov (United States)

    Macías-García, B; González-Fernández, L; Loux, S C; Rocha, A M; Guimarães, T; Peña, F J; Varner, D D; Hinrichs, K

    2015-01-01

    Repeatable methods for IVF have not been established in the horse, reflecting the failure of standard capacitating media to induce changes required for fertilization capacity in equine sperm. One important step in capacitation is membrane cholesterol efflux, which in other species is triggered by cholesterol oxidation and is typically enhanced using albumin as a sterol acceptor. We incubated equine sperm in the presence of calcium, BSA, and bicarbonate, alone or in combination. Bicarbonate induced an increase in reactive oxygen species (ROS) that was abolished by the addition of calcium or BSA. Bicarbonate induced protein tyrosine phosphorylation (PY), even in the presence of calcium or BSA. Incubation at high pH enhanced PY but did not increase ROS production. Notably, no combination of these factors was associated with significant cholesterol efflux, as assessed by fluorescent quantitative cholesterol assay and confirmed by filipin staining. By contrast, sperm treated with methyl-β-cyclodextrin showed a significant reduction in cholesterol levels, but no significant increase in PY or ROS. Presence of BSA increased sperm binding to bovine zonae pellucidae in all three stallions. These results show that presence of serum albumin is not associated with a reduction in membrane cholesterol levels in equine sperm, highlighting the failure of equine sperm to exhibit core capacitation-related changes in a standard capacitating medium. These data indicate an atypical relationship among cholesterol efflux, ROS production, and PY in equine sperm. Our findings may help to elucidate factors affecting failure of equine IVF under standard conditions. © 2015 Society for Reproduction and Fertility.

  20. Office-based sperm concentration: A simplified method for ...

    African Journals Online (AJOL)

    Methods: Semen samples from 51 sperm donors were used. Following swim-up separation, the sperm concentration of the retrieved motile fraction was counted, as well as progressive motile sperm using a standardised wet preparation. The number of sperm in a 10 μL droplet covered with a 22 × 22 mm coverslip was ...

  1. Case competitions

    DEFF Research Database (Denmark)

    Schjoldager, Anne Gram

    2009-01-01

    The paper presents and discusses a teaching project with case competitions for MA students of specialised translation at the Aarhus School of Business, Aarhus University. Drawing on a series of online questionnaires, the paper ascertains how the project was evaluated by the participating students...

  2. EDITORIAL: Physics competitions Physics competitions

    Science.gov (United States)

    Jordens, H.; Mathelitsch, L.

    2009-11-01

    1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

  3. Redox regulation of mammalian sperm capacitation

    Directory of Open Access Journals (Sweden)

    Cristian O′Flaherty

    2015-01-01

    Full Text Available Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species (ROS that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD (P H for sperm capacitation. Peroxiredoxins (PRDXs are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility.

  4. Sperm Preservation using Freeze-Drying Method

    Directory of Open Access Journals (Sweden)

    TAKDIR SAILI

    2005-03-01

    Full Text Available Since the discovery of cryopreservation method for bull semen, cryopreservation become an alternative method for maintaining gamet resources of certain animal which is threatened or near extinction. This technology was then applied to the preservation of embryo, oocyte, ovary and testis. The application of intracytoplasmic sperm injection (ICSI for which sperm motility is unnecessary had supported the effort to create simplified method such as freeze-drying for sperm preservation. Due to the benefit of ICSI over the conventional in vitro fertilization (IVF the spermatozoon could be mechanically driven to pass through the zona pellucida and entering the cytoplasm of oocytes prior to fertilization. The freeze-drying method is an alternative method in sperm preservation which ignored the motility of sperm. The sperm resulted from this technique is in drying state, therefore, it might be stored in room temperature or in refrigerator. Many reports have claimed that freeze-dried sperm which is not motile but has an intact DNA was able to fertilize oocytes, even produced offspring in mouse.

  5. Redox regulation of mammalian sperm capacitation

    Science.gov (United States)

    O’Flaherty, Cristian

    2015-01-01

    Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species (ROS) that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD (P) H for sperm capacitation. Peroxiredoxins (PRDXs) are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility. PMID:25926608

  6. Changes of murine sperm phospholipid composition during epididymal maturation determined by MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Pyttel, S; Nimptsch, A; Böttger, J; Zschörnig, K; Jakop, U; Wegener, J; Müller, K; Paasch, U; Schiller, J

    2014-08-01

    After leaving the testis, spermatozoa undergo several important steps of biochemical maturation during the passage through the epididymis, increasing their motility and fertilizing ability. These changes comprise (among others) the modification of the phospholipid composition of the sperm membrane. This process is thought to be important for the achievement of motility and fertilizing capacity. The lipids of the sperm membrane are characterized by a significant content of unsaturated fatty acyl residues, resulting in a high sensitivity against oxidative stress. This is evidenced by the appearance of lysolipids, for example, lysophosphatidylcholine, which acts like a detergent and is normally present in only very small amounts in biological membranes. The epididymis represents a tubular system comprising three main parts (caput, corpus, and cauda), through which the spermatozoa are consecutively transported undergoing distinct maturation stages. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we established three striking differences in the lipid composition of murine spermatozoa from the different epididymal regions: in comparison to the caput sperm, sperm from the cauda are characterized by (1) a higher degree of unsaturation (PC 18:0/22:5 and 18:0/22:6 vs. 18:0/20:4 and 18:0/18:1), (2) an enhanced plasmalogen content, and (3) an enhanced content of lysolipids. These changes are likely to be of physiological relevance and potentially useful as diagnostic markers of sperm maturation and acquisition of motility. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. A competitive immunoassay for ultrasensitive detection of Hg(2+) in water, human serum and urine samples using immunochromatographic test based on surface-enhanced Raman scattering.

    Science.gov (United States)

    She, Pei; Chu, Yanxin; Liu, Chunwei; Guo, Xun; Zhao, Kang; Li, Jianguo; Du, Haijing; Zhang, Xiang; Wang, Hong; Deng, Anping

    2016-02-04

    An immunochromatographic test (ICT) strip was developed for ultrasensitive competitive immunoassay of Hg(2+). This strategy was achieved by combining the easy-operation and rapidity of ICT with the high sensitivity of surface-enhanced Raman scattering (SERS). Monoclonal antibody (mAb) against Hg(2+) and Raman active substance 4-mercaptobenzoic acid (MBA) dual labelled gold nanoparticles (GNPs) were prepared as an immunoprobe. The Raman scattering intensity of MBA on the test line of the ICT strip was measured for quantitative determination of Hg(2+). The ICT was able to directly detect Hg(2+) without complexing due to the specific recognition of the mAb with Hg(2+). The IC50 and limit of detection (LOD) of the assay for Hg(2+) detection were 0.12 ng mL(-1) and 0.45 pg mL(-1), respectively. There was no cross-reactivity (CR) of the assay with other nineteen ions and the ICT strips could be kept for 5 weeks without loss of activity. The recoveries of the assay for water, human serum and urine samples spiked with Hg(2+) were in range of 88.3-107.3% with the relative standard deviations (RSD) of 1.5-9.5% (n = 3). The proposed ICT was used for the detection of Hg(2+) in urine samples collected from Occupational Disease Hospital and the results were confirmed by cold-vapor atomic fluorescence spectroscopy (CV-AFS). The assay exhibited high sensitivity, selectivity, stability, precision and accuracy, demonstrating a promising method for the detection of trace amount of Hg(2+) in environmental water samples and biological serum and urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. The stochastic dance of circling sperm cells: sperm chemotaxis in the plane

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, B M; Juelicher, F [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)], E-mail: ben@pks.mpg.de, E-mail: julicher@pks.mpg.de

    2008-12-15

    Biological systems such as single cells must function in the presence of fluctuations. It has been shown in a two-dimensional experimental setup that sea urchin sperm cells move toward a source of chemoattractant along planar trochoidal swimming paths, i.e. drifting circles. In these experiments, a pronounced variability of the swimming paths is observed. We present a theoretical description of sperm chemotaxis in two dimensions which takes fluctuations into account. We derive a coarse-grained theory of stochastic sperm swimming paths in a concentration field of chemoattractant. Fluctuations enter as multiplicative noise in the equations for the sperm swimming path. We discuss the stochastic properties of sperm swimming and predict a concentration-dependence of the effective diffusion constant of sperm swimming which could be tested in experiments.

  9. The stochastic dance of circling sperm cells: sperm chemotaxis in the plane

    Science.gov (United States)

    Friedrich, B. M.; Jülicher, F.

    2008-12-01

    Biological systems such as single cells must function in the presence of fluctuations. It has been shown in a two-dimensional experimental setup that sea urchin sperm cells move toward a source of chemoattractant along planar trochoidal swimming paths, i.e. drifting circles. In these experiments, a pronounced variability of the swimming paths is observed. We present a theoretical description of sperm chemotaxis in two dimensions which takes fluctuations into account. We derive a coarse-grained theory of stochastic sperm swimming paths in a concentration field of chemoattractant. Fluctuations enter as multiplicative noise in the equations for the sperm swimming path. We discuss the stochastic properties of sperm swimming and predict a concentration-dependence of the effective diffusion constant of sperm swimming which could be tested in experiments.

  10. How accurate is sperm morphology as an indicator of sperm function?

    Science.gov (United States)

    Franken, D R

    2015-08-01

    Sperm morphology has been consistently correlated with fertilisation success or failure. The clinical relevance of the percentage normal spermatozoa has been a widely discussed topic amongst infertility specialists and scientists. This study aimed to evaluate the role of sperm morphology as an indicator of additional sperm functions among 114 andrology referrals. The sperm functions that were investigated included chromatin packaging quality (CMA3 test (n = 109), zona-induced acrosome reaction (ZIAR test; n = 36), hemizona assay (HZI; n = 36) and progressive motility (n = 47). Chromatin packaging quality had a negative and significant (P = 0.0001, r = -0.74) correlation with the percentage normal spermatozoa, while progressive motility had a significant and positive correlation (P = 0.0001, 0.59). Accurate sperm morphology scoring as described by the WHO 2010 manual can therefore be used as an indicator of specific sperm functions. © 2014 Blackwell Verlag GmbH.

  11. Direct action of endocrine disrupting chemicals on human sperm

    DEFF Research Database (Denmark)

    Schiffer, Christian; Müller, Astrid; Egeberg, Dorte L

    2014-01-01

    sperm. We show that structurally diverse EDCs activate the sperm-specific CatSper channel and, thereby, evoke an intracellular Ca(2+) increase, a motility response, and acrosomal exocytosis. Moreover, EDCs desensitize sperm for physiological CatSper ligands and cooperate in low-dose mixtures to elevate...... Ca(2+) levels in sperm. We conclude that EDCs interfere with various sperm functions and, thereby, might impair human fertilization....

  12. Sperm immobilization by dental focus microorganisms.

    Science.gov (United States)

    Linossier, A; Thumann, A; Bustos-Obregon, E

    1982-01-01

    Focal infections and their ability to produce alterations in different tissues have been in dispute for long time. The purpose of this work was to observe "in vitro" the effect of an Escherichia coli filtrate obtained from open pulpar necrosis on human sperm motility. It was observed that the E. coli filtrate produced a loss in sperm motility. The immobilizating factor was studied and characterized as a heat-stable, resistant to lyophilization and non-dializable substance, which could via blood stream reach the male reproductive system and affect sperm motility.

  13. Reproductive success by large, closely related males facilitated by sperm storage in an aggregate breeding amphibian.

    Science.gov (United States)

    Chandler, C H; Zamudio, K R

    2008-03-01

    The outcome of sexual selection on males may depend on female mate choice and male-male competition as well as postcopulatory processes such as cryptic female choice and sperm competition. We studied the outcome of sexual selection in the spotted salamander (Ambystoma maculatum), specifically examining the role of body size and relatedness on male reproductive success. Using controlled mating experiments in the field, we gave females access to three males of different sizes. We used seven microsatellite loci to determine paternity in the resulting larvae, estimate relatedness (r) between females and their mates, and calculate md(2) (a measure of within-individual genomic divergence), heterozygosity, and standardized heterozygosity in the larvae. Both body size and relatedness to the female were significant predictors of male reproductive success. The relatedness of the males available to a female did not influence the amount of stored sperm she used to sire her larvae. Nonetheless, computer simulations showed that the average md(2), heterozygosity, and standardized heterozygosity of the offspring were lower than expected by random mating. These differences are due to the use of stored sperm to fertilize some eggs; md(2), heterozygosity, and standardized heterozygosity of larvae sired by stored sperm were significantly lower than those of larvae sired by the experimental males. These results suggest that relatedness may further influence a male's long-term reproductive success by determining whether his sperm is stored for later breeding seasons. Sexual selection in this salamander likely involves a complex interaction among many factors and may act over many seasons.

  14. Chemical UV Filters Mimic the Effect of Progesterone on Ca2+Signaling in Human Sperm Cells.

    Science.gov (United States)

    Rehfeld, A; Dissing, S; Skakkebæk, N E

    2016-11-01

    Progesterone released by cumulus cells surrounding the egg induces a Ca 2+ influx into human sperm cells via the cationic channel of sperm (CatSper) Ca 2+ channel and controls multiple Ca 2+ -dependent responses essential for fertilization. We hypothesized that chemical UV filters may mimic the physiological action of progesterone on CatSper, thus affecting Ca 2+ signaling in human sperm cells. We examined 29 UV filters allowed in sunscreens in the United States and/or the European Union for their ability to induce Ca 2+ signals in human sperm by applying measurements of the intracellular free Ca 2+ concentration. We found that 13 UV filters induced a significant Ca 2+ signal at 10 μM. Nine UV filters induced Ca 2+ signals primarily by activating the CatSper channel. The UV filters 3-benzylidene camphor (3-BC) and benzylidene camphor sulfonic acid competitively inhibited progesterone-induced Ca 2+ signals. Dose-response relations for the UV filters showed that the Ca 2+ signal-inducing effects began in the nanomolar-micromolar range. Single-cell Ca 2+ measurements showed a Ca 2+ signal-inducing effect of the most potent UV filter, 3-BC, at 10 nM. Finally, we demonstrated that the 13 UV filters acted additively in low-dose mixtures to induce Ca 2+ signals. In conclusion, 13 of 29 examined UV filters (44%) induced Ca 2+ signals in human sperm. Nine UV filters primarily activated CatSper and thereby mimicked the effect of progesterone. The UV filters 3-BC and benzylidene camphor sulfonic acid competitively inhibited progesterone-induced Ca 2+ signals. In vivo exposure studies are needed to investigate whether UV filter exposure affects human fertility.

  15. Ovarian fluid mediates the temporal decline in sperm viability in a fish with sperm storage.

    Directory of Open Access Journals (Sweden)

    Clelia Gasparini

    Full Text Available A loss of sperm viability and functionality during sperm transfer and storage within the female reproductive tract can have important fitness implications by disrupting fertilization and impairing offspring development and survival. Consequently, mechanisms that mitigate the temporal decline in sperm function are likely to be important targets of selection. In many species, ovarian fluid is known to regulate and maintain sperm quality. In this paper, we use the guppy Poecilia reticulata, a highly polyandrous freshwater fish exhibiting internal fertilization and sperm storage, to determine whether ovarian fluid (OF influences the decline in sperm viability (the proportion of live sperm in the ejaculate over time and whether any observed effects depend on male sexual ornamentation. To address these questions we used a paired experimental design in which ejaculates from individual males were tested in vitro both in presence and absence of OF. Our results revealed that the temporal decline in sperm viability was significantly reduced in the presence of OF compared to a saline control. This finding raises the intriguing possibility that OF may play a role in mediating the decline in sperm quality due to the deleterious effects of sperm ageing, although other possible explanations for this observation are discussed. Interestingly, we also show that the age-related decline in sperm viability was contingent on male sexual ornamentation; males with relatively high levels of iridescence (indicating higher sexual attractiveness exhibited a more pronounced decline in sperm viability over time than their less ornamented counterparts. This latter finding offers possible insights into the functional basis for the previously observed trade-off between these key components of pre- and postcopulatory sexual selection.

  16. Comparison of cushioned centrifugation and SpermFilter filtration on longevity and morphology of cooled-stored equine semen.

    Science.gov (United States)

    Roach, J; Schnobrich, M; Ellerbrock, R; Feijo, L; Bradecamp, E; Alvarenga, M A; Kline, K; Canisso, I

    2016-03-05

    This study compares two methods for seminal plasma removal by evaluating sperm recovery rates, and motility and morphology of cooled-stored semen. Ejaculates were divided into three groups: control, filtration and cushioned centrifugation. Semen was extended to 25 million sperm/ml using a skim-milk-based extender and stored at 5°C for all groups. Sperm motility (total motility (%TM) and progressive motility (%PM)) was determined at 0, 24, 48 and 72 hours by a computer-assisted sperm analyser. Sperm morphology was assessed using differential interference microscopy. Overall, %TM of the centrifugation group was significantly higher than the filter group, but not significantly different than the control. No significant difference in %TM or %PM was detected for the control group and filter. Cushioned centrifugation was a superior method to obtain progressively motile sperm compared with control (P=0.03) and filter groups (Pcentrifugation was a superior method to remove seminal plasma while preserving %TM and enhancing %PM for stallions under cooled storage over three days. However, as the differences appear to be negligible, the SpermFilter may represent an alternative for farms lacking a centrifuge. British Veterinary Association.

  17. Reduction of centrifugation force in discontinuous percoll gradients increases in vitro fertilization rates without reducing bovine sperm recovery.

    Science.gov (United States)

    Guimarães, A C G; Leivas, F G; Santos, F W; Schwengber, E B; Giotto, A B; Machado, C I U; Gonçalves, C G M; Folchini, N P; Brum, D S

    2014-05-01

    The objective of this study was to determine the effect of different centrifugation forces in bovine sperm separation by discontinuous Percoll gradients for in vitro fertilization IVF. The semen samples from each bull were pooled or each bull were centrifuged separately and centrifuged in discontinuous Percoll gradients (30, 60 and 90%) at different forces: F1 (9000×g), F2 (6500×g), F3 (4500×g) and F4 (2200×g), according experiment. The sperm samples were evaluated to determine the concentration, motility, vigor, morphology, reactive oxygen species (ROS), integrity of the plasma membrane, lipid peroxidation, antioxidants and embryo development were also evaluated. No difference was observed in the concentration of sperm submitted to different centrifugation forces. The total percentage of motile sperm was increased after centrifugation at F3 and F4, and the ROS production at F1 was greater than the other forces. When the bulls semen were processed individually, no significant differences were observed for the sperm quality parameters between F1 and F4, including lipid peroxidation, antioxidants, cleavage rate and average time to the first cleavage. This work demonstrated for the first time that centrifugation at 2200×g enhanced the sperm penetration and fertilization rates without reducing sperm recovery compared to the typical centrifugation force (9000×g) currently used by the commercial bovine IVF industry. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Power industry and competition

    International Nuclear Information System (INIS)

    Recknagel, H.

    1988-01-01

    A task group on antritrust law has been set in by the Federal Ministry of Economics in order to again investigate the position of the utilities within the framework of the law against restraints on competition, (GWB). The task group's report states that from the power industry's perspective, there is no reason to modify the existing system created by sections 103, 103a of the GWB. The EC internal market to come, and enhanced use of coal for power generation to be continued beyond the year 1995 are topics that will keep politicians, utilities, and lawmakers in this field busy enough. In such a situation, the legislator cannot afford a discovery trip into unexplored, theoretical impacts of enhanced competition on the power industry. (orig./DG) [de

  19. Use of testicular sperm for intracytoplasmic sperm injection in men with high sperm DNA fragmentation: a SWOT analysis

    Science.gov (United States)

    Esteves, Sandro C; Roque, Matheus; Garrido, Nicolás

    2018-01-01

    Spermatozoa retrieved from the testis of men with high levels of sperm DNA fragmentation (SDF) in the neat semen tend to have better DNA quality. Given the negative impact of SDF on the outcomes of Assisted Reproductive Technology (ART), an increased interest has emerged about the use of testicular sperm for intracytoplasmic sperm injection (Testi-ICSI). In this article, we used a SWOT (strengths, weaknesses, opportunities, and threats) analysis to summarize the advantages and drawbacks of this intervention. The rationale of Testi-ICSI is bypass posttesticular DNA fragmentation caused by oxidative stress during sperm transit through the epididymis. Hence, oocyte fertilization by genomically intact testicular spermatozoa may be optimized, thus increasing the chances of creating a normal embryonic genome and the likelihood of achieving a live birth, as recently demonstrated in men with high SDF. However, there is still limited evidence as regards the clinical efficacy of Testi-ICSI, thus creating opportunities for further confirmatory clinical research as well as investigation of Testi-ICSI in clinical scenarios other than high SDF. Furthermore, Testi-ICSI can be compared to other laboratory preparation methods for deselecting sperm with damaged DNA. At present, the available literature supports the use of testicular sperm when performing ICSI in infertile couples whose male partners have posttesticular SDF. Due to inherent risks of sperm retrieval, Testi-ICSI should be offered when less invasive treatments for alleviating DNA damage have failed. A call for continuous monitoring is nonetheless required concerning the health of generated offspring and the potential complications of sperm retrieval. PMID:28440264

  20. Use of testicular sperm for intracytoplasmic sperm injection in men with high sperm DNA fragmentation: a SWOT analysis.

    Science.gov (United States)

    Esteves, Sandro C; Roque, Matheus; Garrido, Nicolás

    2018-01-01

    Spermatozoa retrieved from the testis of men with high levels of sperm DNA fragmentation (SDF) in the neat semen tend to have better DNA quality. Given the negative impact of SDF on the outcomes of Assisted Reproductive Technology (ART), an increased interest has emerged about the use of testicular sperm for intracytoplasmic sperm injection (Testi-ICSI). In this article, we used a SWOT (strengths, weaknesses, opportunities, and threats) analysis to summarize the advantages and drawbacks of this intervention. The rationale of Testi-ICSI is bypass posttesticular DNA fragmentation caused by oxidative stress during sperm transit through the epididymis. Hence, oocyte fertilization by genomically intact testicular spermatozoa may be optimized, thus increasing the chances of creating a normal embryonic genome and the likelihood of achieving a live birth, as recently demonstrated in men with high SDF. However, there is still limited evidence as regards the clinical efficacy of Testi-ICSI, thus creating opportunities for further confirmatory clinical research as well as investigation of Testi-ICSI in clinical scenarios other than high SDF. Furthermore, Testi-ICSI can be compared to other laboratory preparation methods for deselecting sperm with damaged DNA. At present, the available literature supports the use of testicular sperm when performing ICSI in infertile couples whose male partners have posttesticular SDF. Due to inherent risks of sperm retrieval, Testi-ICSI should be offered when less invasive treatments for alleviating DNA damage have failed. A call for continuous monitoring is nonetheless required concerning the health of generated offspring and the potential complications of sperm retrieval.

  1. EDITORIAL: Physics competitions Physics competitions

    Science.gov (United States)

    Jordens, H.; Mathelitsch, L.

    2010-07-01

    This editorial opens the second special section on physics competitions in European Journal of Physics. In the first section last year, we asked for feedback on the idea of such a section and on the content of the articles. We received no answer whatsoever, which can be interpreted in two ways: the section is not interesting enough to raise motivation for feedback, or the reader is satisfied. Having no indication which scenario is the correct one, we are optimistic and favour the second. The section at hand contains three articles. Again, as last year, the organizer of the annual Olympiad reports on tasks and outcomes of this competition. The Olympiad took place in Merida, Mexico, and was by far the largest event with 316 contestants from 68 countries. Again, the predominance of Asian/Chinese students was manifest, showing how serious the training is taken by both their authorities and students. Unfortunately, the winners of the last International Young Physicists' Tournament (IYPT), the team from Korea, did not accept the offer to report on their prize-winning contribution. We are thankful that two students from Austria, who achieved second place with their team, took over and reported on the task which they presented in the finals of the competition. It connects the fields of sport and physics and explains a special move in skateboarding. The third contribution introduces a different competition, 'International Conference of Young Scientists'. On one hand, as in the Olympiad, it addresses individuals, not teams. On the other, as in the IYPT, students have several months to prepare and also the quality of the presentation is an important element of the judgment. In fact, this competition comes closer to real scientific research compared to the other events. Finally and again, we hope that this section will serve several purposes: To show the competitions as a very important tool in the support of gifted students. To raise awareness amongst university teachers, and

  2. Motile sperm organelle morphology examination (MSOME) and sperm head vacuoles: state of the art in 2013.

    Science.gov (United States)

    Perdrix, Anne; Rives, Nathalie

    2013-01-01

    BACKGROUND Approximately 10 years after the first publication introducing the motile sperm organelle morphology examination (MSOME), many questions remained about sperm vacuoles: frequency, size, localization, mode of occurrence, biological significance and impact on male fertility potential. Many studies have tried to characterize sperm vacuoles, to determine the sperm abnormalities possibly associated with vacuoles, to test the diagnostic value of MSOME for male infertility or to question the benefits of intracytoplasmic morphologically selected sperm injection (IMSI). METHODS We searched PubMed for articles in the English language published in 2001-2012 regarding human sperm head vacuoles, MSOME and IMSI. RESULTS A bibliographic analysis revealed consensus for the following findings: (i) sperm vacuoles appeared frequently, often multiple and preferentially anterior; (ii) sperm vacuoles and sperm chromatin immaturity have been associated, particularly in the case of large vacuoles; (iii) teratozoospermia was a preferred indication of MSOME and IMSI. CONCLUSION The high-magnification system appears to be a powerful method to improve our understanding of human spermatozoa. However, its clinical use remains unclear in the fields of male infertility diagnosis and assisted reproduction techniques (ARTs).

  3. Importance of sperm morphology during sperm transport and fertilization in mammals

    Directory of Open Access Journals (Sweden)

    Francisco A García-Vázquez

    2016-01-01

    Full Text Available After natural or artificial insemination, the spermatozoon starts a journey from the site of deposition to the place of fertilization. However, only a small subset of the spermatozoa deposited achieves their goal: to reach and fertilize the egg. Factors involved in controlling sperm transport and fertilization include the female reproductive tract environment, cell-cell interactions, gene expression, and phenotypic sperm traits. Some of the significant determinants of fertilization are known (i.e., motility or DNA status, but many sperm traits are still indecipherable. One example is the influence of sperm dimensions and shape upon transport within the female genital tract towards the oocyte. Biophysical associations between sperm size and motility may influence the progression of spermatozoa through the female reproductive tract, but uncertainties remain concerning how sperm morphology influences the fertilization process, and whether only the sperm dimensions per se are involved. Moreover, such explanations do not allow the possibility that the female tract is capable of distinguishing fertile spermatozoa on the basis of their morphology, as seems to be the case with biochemical, molecular, and genetic properties. This review focuses on the influence of sperm size and shape in evolution and their putative role in sperm transport and selection within the uterus and the ability to fertilize the oocyte.

  4. Logo competition

    CERN Multimedia

    Staff Association

    2013-01-01

    Award of the prizes The price ceremony for the Staff Association’s new logo competition which took place on Friday 1st March at 5 p.m. was a big success. The first prize, an Ezee Suisse electric bike, was won by Paulo Rios, from Portugal. In his absence, the bike was handed to his brother Vitor. The other five winners of the competition also received their prize: Go Sport vouchers. A peize draw was then organized to award 22 other participants with prizes offered by our commercial partners (Aquaparc, BCGE, L’Occitane, Passeport Gourmand, Sephora, Theater La Comédie de Genève), whom we would like to warmly thank. After all prices were distributed the evening continued with discussions around a friendly drink.

  5. Driving Competitiveness Through Servitization

    DEFF Research Database (Denmark)

    Avlonitis, Viktor; Frandsen, Thomas; Hsuan, Juliana

    Servitization, or adding services to the manufactured product, has become a strategy for increasing financial margins, getting closer to the customer and prolonging product lives. This is especially applicable to Western hemisphere companies in their efforts to compete with companies from low cos...... for the company. This booklet is produced to serve as a documentation of a research project together with industry on how servitization can be a strategy to enhance the competitiveness of manufacturing firms....

  6. Strategic Accessibility Competition

    OpenAIRE

    Bacchiega, Emanuele; Randon, Emanuela; Zirulia, Lorenzo

    2010-01-01

    We analyze the effect of competition in market-accessibility enhancement among quality-differentiated firms. Firms are located in regions with different ex-ante transport costs to reach the final market. We characterize the equilibrium of the two-stage game in which firms first invest to improve market accessibility and then compete in prices. Efforts in accessibility improvement crucially depend on the interplay between the willingness to pay for the quality premium of the median consumer an...

  7. Measuring competitiveness

    OpenAIRE

    J. Peter Neary

    2005-01-01

    An earlier version was presented at the Conference on Macroeconomic Perspectives in Honour of Brendan M. Walsh, held at University College Dublin on 7 October, 2005 This paper reviews alternative approaches to measuring an economy?s cost competitiveness and proposes some new measures inspired by the economic theory of index numbers. The indices provide a theoretical benchmark for estimated real effective exchange rates, but differ from standard measures in that they are based on marginal r...

  8. Optimal Competition : A Benchmark for Competition Policy

    NARCIS (Netherlands)

    Boone, J.

    2003-01-01

    This paper introduces optimal competition: the best form of competition in an industry that a competition authority can achieve under the information constraint that it cannot observe firms' effciency levels.We show that the optimal competition outcome in an industry becomes more competitive as more

  9. Intracellular pH in sperm physiology.

    Science.gov (United States)

    Nishigaki, Takuya; José, Omar; González-Cota, Ana Laura; Romero, Francisco; Treviño, Claudia L; Darszon, Alberto

    2014-08-01

    Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca(2+) channel; Slo3, a K(+) channel; the sperm-specific Na(+)/H(+) exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Function of the sperm nuclear matrix.

    Science.gov (United States)

    Shaman, Jeffrey A; Yamauchi, Yasuhiro; Ward, W Steven

    2007-01-01

    Mammalian spermatozoa contain some of the most highly compact chromatin. This is due to the DNA binding proteins, the protamines, which replace most of the histones during spermiogenesis. This chromatin, however, shares some features with somatic cell chromatin. One of these is the organization of DNA into loop domains attached at their bases to a proteinaceous nuclear matrix. Several groups have shown that the sites at which DNA associates with the sperm nuclear matrix contain chromatin structures that are linked with specific functions. Recent data also suggest that the sperm nuclear matrix plays essential roles in the paternal pronucleus of the newly fertilized oocyte, suggesting that the sperm cell provides more information to the new embryo than solely the genetic material it delivers. Here, we will review these data which together give insight into the functional significance and requirements of sperm nuclear structure.

  11. Life after Death. Sperm, Property, and Hope

    DEFF Research Database (Denmark)

    Kroløkke, Charlotte; Willum Adrian, Stine

    A tragic workplace accident led in 2010 to the death of Mark Edwards. Subsequently, his wife Joycelyn Edwards requested for the New South Wales Superior Court´s permission to extract sperm posthumous from her husband. She got the permission and one year later, the Court decided to grant her access...... Danish legal and bioethical discussions on the use of dead men’s sperm, and similar debates in New South Wales that led to the Edwards court ruling....... to the sperm her husband had deposited. Following a vivid media debate has taken place while the legislation was processed in the Parliament changing the legislation by legalizing the use of sperm from a dead man. Freezing technologies and extraction techniques has with the development of new reproductive...

  12. Mammalian Sperm Motility: Observation and Theory

    KAUST Repository

    Gaffney, E.A.

    2011-01-21

    Mammalian spermatozoa motility is a subject of growing importance because of rising human infertility and the possibility of improving animal breeding. We highlight opportunities for fluid and continuum dynamics to provide novel insights concerning the mechanics of these specialized cells, especially during their remarkable journey to the egg. The biological structure of the motile sperm appendage, the flagellum, is described and placed in the context of the mechanics underlying the migration of mammalian sperm through the numerous environments of the female reproductive tract. This process demands certain specific changes to flagellar movement and motility for which further mechanical insight would be valuable, although this requires improved modeling capabilities, particularly to increase our understanding of sperm progression in vivo. We summarize current theoretical studies, highlighting the synergistic combination of imaging and theory in exploring sperm motility, and discuss the challenges for future observational and theoretical studies in understanding the underlying mechanics. © 2011 by Annual Reviews. All rights reserved.

  13. Rat sperm motility analysis: methodologic considerations

    Science.gov (United States)

    The objective of these studies was to optimize conditions for computer-assisted sperm analysis (CASA) of rat epididymal spermatozoa. Methodologic issues addressed include sample collection technique, sampling region within the epididymis, type of diluent medium used, and sample c...

  14. Is lithium essential for epididymal sperm maturation?

    Science.gov (United States)

    Halder, Tanmoy; Datta, Uttam; Basu, Siddhartha; Mukherjee, Prasenjit

    2016-11-01

    A wider biological role of ultratrace element lithium in the mammalian reproduction has been reported, however, presence of lithium in the epididymal luminal fluid (ELF) and its influence on sperm during maturation events in the epididymal regions are still unknown. A pilot study was carried out in Jamunapari buck which revealed that levels of lithium in the ELF diminished gradually and significantly (Psperm were observed, except spermatozoan motility that was found absent in the caput epididymis. Therefore, we hypothesize that levels of lithium in the epididymal regions is one of the motility initiation and/or regulatory factor for epididymal sperm maturation essential for acquiring fertilizing competence of sperm cells, hence, lithium could also be considered as one of the biomarker of sperm maturation in any species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. A unique cytoskeleton associated with crawling in the amoeboid sperm of the nematode, Ascaris suum

    Science.gov (United States)

    1989-01-01

    Nematode sperm extend pseudopods and pull themselves over substrates. They lack an axoneme or the actin and myosins of other types of motile cells, but their pseudopods contain abundant major sperm protein (MSP), a family of 14-kD polypeptides found exclusively in male gametes. Using high voltage electron microscopy, a unique cytoskeleton was discovered in the pseudopod of in vitro-activated, crawling sperm of the pig intestinal nematode Ascaris suum. It consists of 5-10-nm fuzzy fibers organized into 150-250-nm-thick fiber complexes, which connect to each of the moving pseudopodial membrane projections, villipodia, which in turn make contact with the substrate. Individual fibers in a complex splay out radially from its axis in all directions. The centripetal ends intercalate with fibers from other complexes or terminate in a thickened layer just beneath the pseudopod membrane. Monoclonal antibodies directed against MSP heavily label the fiber complexes as well as individual pseudopodial filaments throughout their length. This represents the first evidence that MSP may be the major filament protein in the Ascaris sperm cytoskeleton. The large fiber complexes can be seen clearly in the pseudopods of live, crawling sperm by computer-enhanced video, differential-interference contrast microscopy, forming with the villipodia at the leading edge of the sperm pseudopod. Even before the pseudopod attaches, the entire cytoskeleton and villipodia move continuously rearwards in unison toward the cell body. During crawling, complexes and villipodia in the pseudopod recede at the same speed as the spermatozoon moves forward, both disappearing at the pseudopod-cell body junction. Sections at this region of high membrane turnover reveal a band of densely packed smooth vesicles with round and tubular profiles, some of which are associated with the pseudopod plasma membrane. The exceptional anatomy, biochemistry, and phenomenology of Ascaris sperm locomotion permit direct study of

  16. The sperm epigenome: implications for the embryo.

    Science.gov (United States)

    Gannon, John R; Emery, Benjamin R; Jenkins, Timothy G; Carrell, Douglas T

    2014-01-01

    Recent advances, including the human genome project and numerous studies of cancer and other diseases, have shown that the genetic code is not simply limited to the sequence of the four bases of DNA but also includes epigenetic programming, heritable changes that affect gene expression [Riggs A, Martinssen R, Russo V (2007) Introduction. In: Riggs A, Martinssen R, Russo V (eds) Epigenetics mechanisms of gene regulation. Cold Spring Harbor Press, New York]. The science of epigenetics is important in understanding many diseases and biological processes, including in identifying the causes of disease and better understanding the mechanisms by which the environment can affect gene expression [Carrell Fertil Steril 97 (2):267-274, 2012]. This chapter will focus on the epigenome of sperm and particularly highlight the potential role of the sperm epigenome in embryogenesis.The sperm epigenome is unique and highly specialized because of the unique nature and function of sperm and because of the diverse requirements for successful fertilization. Due to the need for motility, sperm chromatin must be compacted and highly organized. During spermiogenesis the chromatin is packaged tightly into the sperm head by the replacement of most histones with protamines. This allows for protection of the DNA from the hostile environment in the female reproductive tract. Remaining histones can have chemical modifications to the tails of the protein that either facilitate or repress gene transcription. Sperm, like embryonic stem cells, have a unique pattern of histone modifications that includes both activating and silencing marks in the promoters of genes associated with development. These bivalent marks, along with DNA hypomethylation, comprise a unique state in which the key genes are "poised" for possible activation in embryogenesis. Sperm epigenetic abnormalities have been linked with multiple diseases including male factor infertility and poor embryogenesis.

  17. Elucidation of the involvement of p14, a sperm protein during maturation, capacitation and acrosome reaction of caprine spermatozoa.

    Directory of Open Access Journals (Sweden)

    Pinki Nandi

    Full Text Available Mammalian sperm capacitation is an essential prerequisite to fertilization. Although progress is being made in understanding the physiology and biochemistry of capacitation, little has been yet explored about the potential role(s of individual sperm cell protein during this process. Therefore elucidation of the role of different sperm proteins in the process of capacitation might be of great importance to understand the process of fertilization. The present work describes the partial characterization of a 14-kDa protein (p14 detected in goat spermatozoa using an antibody directed against the purified protein. Confocal microscopic analysis reveals that the protein is present in both the intracellular and extracellular regions of the acrosomal and postacrosomal portion of caudal sperm head. Though subcellular localization shows that p14 is mainly cytosolic, however it is also seen to be present in peripheral plasma membrane and soluble part of acrosome. Immuno-localization experiment shows change in the distribution pattern of this protein upon induction of capacitation in sperm cells. Increased immunolabeling in the anterior head region of live spermatozoa is also observed when these cells are incubated under capacitating conditions, whereas most sperm cells challenged with the calcium ionophore A23187 to acrosome react, lose their labeling almost completely. Intracellular distribution of p14 also changes significantly during acrosome reaction. Interestingly, on the other hand the antibody raised against this 14-kDa sperm protein enhances the forward motility of caprine sperm cells. Rose-Bengal staining method shows that this anti-p14 antibody also decreases the number of acrosome reacted cells if incubated with capacitated sperm cells before induction of acrosome reaction. All these results taken together clearly indicate that p14 is intimately involved and plays a critical role in the acrosomal membrane fusion event.

  18. Seasonal changes in reproductive activity, sperm variables and sperm freezability in Blanca Andaluza bucks

    Energy Technology Data Exchange (ETDEWEB)

    Gallego-Calvo, L.; Gatica, M.C.; Santiago-Moreno, J.; Guzmán, J.L.; Zarazaga, L.

    2015-07-01

    Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001). No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05). After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05). These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer. (Author)

  19. Seasonal changes in reproductive activity, sperm variables and sperm freezability in Blanca Andaluza bucks

    Directory of Open Access Journals (Sweden)

    Lourdes Gallego-Calvo

    2015-12-01

    Full Text Available Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001. No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05. After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05. These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer.

  20. Oxidative stress in zebrafish (Danio rerio sperm.

    Directory of Open Access Journals (Sweden)

    Mary Hagedorn

    Full Text Available Laboratories around the world have produced tens of thousands of mutant and transgenic zebrafish lines. As with mice, maintaining all of these valuable zebrafish genotypes is expensive, risky, and beyond the capacity of even the largest stock centers. Because reducing oxidative stress has become an important aspect of reducing the variability in mouse sperm cryopreservation, we examined whether antioxidants might improve cryopreservation of zebrafish sperm. Four experiments were conducted in this study. First, we used the xanthine-xanthine oxidase (X-XO system to generate reactive oxygen species (ROS. The X-XO system was capable of producing a stress reaction in zebrafish sperm reducing its sperm motility in a concentration dependent manner (P0.05, whereas superoxide dismutase (SOD and vitamin E did not (P0.05, producing a mean 2.0 to 2.9-fold increase in post-thaw motility. Fourth, we examined the effect of additional cryoprotectants and CAT on fresh sperm motility. Cryoprotectants, 8% methanol and 10% dimethylacetamide (DMA, reduced the motility over the control value (P0.05. Zebrafish sperm protocols should be modified to improve the reliability of the cryopreservation process, perhaps using a different cryoprotectant. Regardless, the simple addition of CAT to present-day procedures will significantly improve this process, assuring increased and less variable fertilization success and allowing resource managers to dependably plan how many straws are needed to safely cryopreserve a genetic line.

  1. Viscoelasticity promotes collective swimming of sperm

    Science.gov (United States)

    Tung, Chih-Kuan; Harvey, Benedict B.; Fiore, Alyssa G.; Ardon, Florencia; Suarez, Susan S.; Wu, Mingming

    From flocking birds to swarming insects, interactions of organisms large and small lead to the emergence of collective dynamics. Here, we report striking collective swimming of bovine sperm, with sperm orienting in the same direction within each cluster, enabled by the viscoelasticity of the fluid. A long-chain polyacrylamide solution was used as a model viscoelastic fluid such that its rheology can be fine-tuned to mimic that of bovine cervical mucus. In viscoelastic fluid, sperm formed dynamic clusters, and the cluster size increased with elasticity of the polyacrylamide solution. In contrast, sperm swam randomly and individually in Newtonian fluids of similar viscosity. Analysis of the fluid motion surrounding individual swimming sperm indicated that sperm-fluid interaction is facilitated by the elastic component of the fluid. We note that almost all biological fluids (e.g. mucus and blood) are viscoelastic in nature, this finding highlights the importance of fluid elasticity in biological function. We will discuss what the orientation fluctuation within a cluster reveals about the interaction strength. Supported by NIH Grant 1R01HD070038.

  2. Oxidative stress negatively affects human sperm mitochondrial respiration.

    Science.gov (United States)

    Ferramosca, Alessandra; Pinto Provenzano, Sara; Montagna, Daniela Domenica; Coppola, Lamberto; Zara, Vincenzo

    2013-07-01

    To correlate the level of oxidative stress in serum and seminal fluid and the level of sperm deoxyribonucleic acid (DNA) fragmentation with sperm mitochondrial respiratory efficiency. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. A possible relationship between sperm mitochondrial respiratory efficiency, the level of oxidative stress, and the level of sperm DNA fragmentation was investigated. Sperm motility was positively correlated with mitochondrial respiration but negatively correlated with oxidative stress and DNA fragmentation. Interestingly, sperm mitochondrial respiratory activity was negatively affected by oxidative stress and DNA fragmentation. Our data indicate that sperm mitochondrial respiration is decreased in patients with high levels of reactive oxygen species by an uncoupling between electron transport and adenosine triphosphate synthesis. This reduction in mitochondrial functionality might be 1 of the reasons responsible for the decrease in spermatozoa motility. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. A competitive immunoassay for ultrasensitive detection of Hg{sup 2+} in water, human serum and urine samples using immunochromatographic test based on surface-enhanced Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    She, Pei; Chu, Yanxin [The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123 (China); Liu, Chunwei; Guo, Xun [OptoTrace (Suzhou) Technologies, Inc., STE 316, Building 4, No. 218, Xinghu Street, bioBAY, Suzhou Industrial Park, Suzhou 215123 (China); Zhao, Kang [The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123 (China); Li, Jianguo, E-mail: lijgsd@suda.edu.cn [The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123 (China); Du, Haijing; Zhang, Xiang [The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123 (China); Wang, Hong [OptoTrace (Suzhou) Technologies, Inc., STE 316, Building 4, No. 218, Xinghu Street, bioBAY, Suzhou Industrial Park, Suzhou 215123 (China); Deng, Anping, E-mail: denganping@suda.edu.cn [The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123 (China)

    2016-02-04

    An immunochromatographic test (ICT) strip was developed for ultrasensitive competitive immunoassay of Hg{sup 2+}. This strategy was achieved by combining the easy-operation and rapidity of ICT with the high sensitivity of surface-enhanced Raman scattering (SERS). Monoclonal antibody (mAb) against Hg{sup 2+} and Raman active substance 4-mercaptobenzoic acid (MBA) dual labelled gold nanoparticles (GNPs) were prepared as an immunoprobe. The Raman scattering intensity of MBA on the test line of the ICT strip was measured for quantitative determination of Hg{sup 2+}. The ICT was able to directly detect Hg{sup 2+} without complexing due to the specific recognition of the mAb with Hg{sup 2+}. The IC{sub 50} and limit of detection (LOD) of the assay for Hg{sup 2+} detection were 0.12 ng mL{sup −1} and 0.45 pg mL{sup −1}, respectively. There was no cross-reactivity (CR) of the assay with other nineteen ions and the ICT strips could be kept for 5 weeks without loss of activity. The recoveries of the assay for water, human serum and urine samples spiked with Hg{sup 2+} were in range of 88.3–107.3% with the relative standard deviations (RSD) of 1.5–9.5% (n = 3). The proposed ICT was used for the detection of Hg{sup 2+} in urine samples collected from Occupational Disease Hospital and the results were confirmed by cold-vapor atomic fluorescence spectroscopy (CV-AFS). The assay exhibited high sensitivity, selectivity, stability, precision and accuracy, demonstrating a promising method for the detection of trace amount of Hg{sup 2+} in environmental water samples and biological serum and urine samples. - Highlights: • The proposed ICT was able to directly detect Hg{sup 2+} without formation of Hg{sup 2+}-ligand complex. • The proposed ICT exhibited high sensitivity, specificity, stability, precision and accuracy for Hg{sup 2+} detection. • The proposed ICT was applicable for the detection of trace amount of Hg{sup 2+} in water, human serum and urine samples.

  4. A competitive immunoassay for ultrasensitive detection of Hg2+ in water, human serum and urine samples using immunochromatographic test based on surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    She, Pei; Chu, Yanxin; Liu, Chunwei; Guo, Xun; Zhao, Kang; Li, Jianguo; Du, Haijing; Zhang, Xiang; Wang, Hong; Deng, Anping

    2016-01-01

    An immunochromatographic test (ICT) strip was developed for ultrasensitive competitive immunoassay of Hg 2+ . This strategy was achieved by combining the easy-operation and rapidity of ICT with the high sensitivity of surface-enhanced Raman scattering (SERS). Monoclonal antibody (mAb) against Hg 2+ and Raman active substance 4-mercaptobenzoic acid (MBA) dual labelled gold nanoparticles (GNPs) were prepared as an immunoprobe. The Raman scattering intensity of MBA on the test line of the ICT strip was measured for quantitative determination of Hg 2+ . The ICT was able to directly detect Hg 2+ without complexing due to the specific recognition of the mAb with Hg 2+ . The IC 50 and limit of detection (LOD) of the assay for Hg 2+ detection were 0.12 ng mL −1 and 0.45 pg mL −1 , respectively. There was no cross-reactivity (CR) of the assay with other nineteen ions and the ICT strips could be kept for 5 weeks without loss of activity. The recoveries of the assay for water, human serum and urine samples spiked with Hg 2+ were in range of 88.3–107.3% with the relative standard deviations (RSD) of 1.5–9.5% (n = 3). The proposed ICT was used for the detection of Hg 2+ in urine samples collected from Occupational Disease Hospital and the results were confirmed by cold-vapor atomic fluorescence spectroscopy (CV-AFS). The assay exhibited high sensitivity, selectivity, stability, precision and accuracy, demonstrating a promising method for the detection of trace amount of Hg 2+ in environmental water samples and biological serum and urine samples. - Highlights: • The proposed ICT was able to directly detect Hg 2+ without formation of Hg 2+ -ligand complex. • The proposed ICT exhibited high sensitivity, specificity, stability, precision and accuracy for Hg 2+ detection. • The proposed ICT was applicable for the detection of trace amount of Hg 2+ in water, human serum and urine samples.

  5. Multi-Objective Optimization Algorithm Based on Sperm Fertilization Procedure (MOSFP

    Directory of Open Access Journals (Sweden)

    Hisham A. Shehadeh

    2017-10-01

    Full Text Available In this paper, we propose an extended multi-objective version of single objective optimization algorithm called sperm swarm optimization algorithm. The proposed multi-objective optimization algorithm based on sperm fertilization procedure (MOSFP operates based on Pareto dominance and a crowding factor, that crowd and filter out the list of the best sperms (global best values. We divide the sperm swarm into three equal parts, after that, different types of turbulence (mutation operators are applied on these parts, such as uniform mutation, non-uniform mutation, and without any mutation. Our algorithm is compared against three well-known algorithms in the field of optimization. These algorithms are NSGA-II, SPEA2, and OMOPSO. These algorithms are compared using a very popular benchmark function suites called Zitzler-Deb-Thiele (ZDT and Walking-Fish-Group (WFG. We also adopt three quality metrics to compare the convergence, accuracy, and diversity of these algorithms, including, inverted generational distance (IGD, spread (SP, and epsilon (∈. The experimental results show that the performance of the proposed MOSFP is highly competitive, which outperformed OMOPSO in solving problems such as ZDT3, WFG5, and WFG8. In addition, the proposed MOSFP outperformed both of NSGA-II or SPEA2 algorithms in solving all the problems.

  6. Phenotypic plasticity in sperm traits in scorpionflies (Mecoptera : Panorpidae): Consequences of larval history and seasonality on sperm length and sperm transfer

    NARCIS (Netherlands)

    Vermeulen, Andreas; Engels, Sierk; Engqvist, Leif; Sauer, Klaus Peter

    2009-01-01

    We examined effects of seasonality, larval food availability and larval rearing density on sperm length, sperm transfer rates and body size in the bivoltine scorpionfly Panorpa vulgaris. Males of the first annual generation were larger and had larger sperm. Comparing individuals of two summer

  7. International Competitiveness

    OpenAIRE

    Jan Fagerberg

    1988-01-01

    This paper develops and tests a model of differing trends in international competitiveness and economic growth across countries. The model relates the development of market shares at home and abroad to three sets of factors: the ability to compete in technology, the ability to compete in delivery(capacity) and the ability to compete in price. The test, using data for 15 OECD countries for the period 1961-1983, shows that in the medium and long run, factors related to technology and capacity a...

  8. Toward microfluidic sperm refinement: continuous flow label-free analysis and sorting of sperm cells

    NARCIS (Netherlands)

    de Wagenaar, B.; Dekker, Stefan; van den Berg, Albert; Segerink, Loes Irene

    2015-01-01

    This manuscript reports upon the development of a microfluidic setup to detect and sort sperm cells from polystyrene beads label-free and non-invasively. Detection is performed by impedance analysis. When sperm cells passed the microelectrodes, the recorded impedance (19.6 ± 5.7 Ω) was higher

  9. Accountings of Selecting Sperm on the (ethical) border

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    During the past years, Denmark has become a destination for fertility travellers, in need for donated sperm. Today, treatment is possible no matter of marital status or sexuality. Furthermore, users of sperm donation can choose between anonymous and non-anonymous sperm, with either basic informat......During the past years, Denmark has become a destination for fertility travellers, in need for donated sperm. Today, treatment is possible no matter of marital status or sexuality. Furthermore, users of sperm donation can choose between anonymous and non-anonymous sperm, with either basic...

  10. Examining Container Port Resources and Environments to Enhance Competitiveness: A Cross-Country Study from Resource-Based and Institutional Perspectives1

    Directory of Open Access Journals (Sweden)

    Hyuksoo CHO

    2015-09-01

    Full Text Available This study aims to analyze the competitiveness of container ports using a cross-country analysis with theoretical foundations. Tangible and intangible resources are discussed as determinants of container port competitiveness using the resource-based view and the institutional theory. This study analyzes the relationships among six variables: container port competitiveness, traffic volume, quality of infrastructure, linear shipping connectivity, operating efficiency, and institutional influence. This study retrieved country-level data on different indicators and countries from several trade and maritime databases. Structural Equation Modeling (SEM is used to test various hypotheses and to evaluate the casual relationships among six variables. Additionally, Ordinary Least Squares (OLS regression is used to test the moderating effects of institutional influence.

  11. Enhanced Accessibility of Polycyclic Aromatic Hydrocarbons (PAHs) and Heterocyclic PAHs in Industrially Contaminated Soil after Passive Dosing of a Competitive Sorbate

    DEFF Research Database (Denmark)

    Humel, Stefan; Nørgaard Schmidt, Stine; Sumetzberger-Hasinger, Marion

    2017-01-01

    To assess the exposure to polycyclic aromatic hydrocarbons (PAHs) it is important to understand the binding mechanisms between specific soil constituents and the organic pollutant. In this study, sorptive bioaccessibility extraction (SBE) was applied to quantify the accessible PAH fraction...... in industrially contaminated soil with and without passive dosing of a competitive sorbate. SBE experiments revealed an accessible PAH fraction of 41 ± 1% (∑16 US EPA PAHs + 5 further PAHs). The passive dosing of toluene below its saturation level revealed competitive binding and resulted in an average increase.......4% PAH. We explain increased PAH desorption after addition of toluene by competitive adsorption to high-affinity sorption sites while acknowledging that toluene could additionally have increased PAH mobility within the soil matrix. Findings suggest that the presence of copollutants at contaminated sites...

  12. What use is an infertile sperm? A comparative study of sperm-heteromorphic Drosophila

    DEFF Research Database (Denmark)

    Holman, Luke; Freckleton, Robert P; Snook, Rhonda R

    2007-01-01

    Sperm size and number are important determinants of male reproductive success. The genus Drosophila exhibits a remarkable diversity of sperm production strategies, including the production of multiple sperm morphs by individual males, a phenomenon called sperm heteromorphism. Sperm......-heteromorphic Drosophila species in the obscura group produce large numbers of infertile "parasperm" in addition to fertile eusperm. Parasperm have been hypothesized to perform a number of roles in place of fertilization, predominantly focused on their potential function in postcopulatory sexual selection. However......, the evolutionary significance of parasperm remains unknown. Here we measured several male and female morphological, behavioral, and life-history traits in 13 obscura group species to test competing hypotheses of parasperm function using comparative methods. We found that parasperm size was unrelated to female...

  13. Thyroxin Is Useful to Improve Sperm Motility

    Directory of Open Access Journals (Sweden)

    Mendeluk Gabriela Ruth

    2016-07-01

    Full Text Available Background The aim of this study was to evaluate the non-genomic action of thyroxin on sperm kinetic and its probable use to improve sperm recovery after applying an en- richment method like “swim-up” in comparison with the available one, pentoxifylline. Materials and Methods This is an experimental study. A total of 50 patients were re- cruited, followed by infertility consultation. Conventional sperm assays were performed according to World Health Organization criteria-2010 (WHO-2010. A Computer Aided Semen Analysis System was employed to assess kinetic parameters and concentrations. Number of the motile sperm recovered after preparation technique was calculated. Results Addition of T4 (0.002 µg/ml to semen samples increased hypermotility at 20 minutes (control: 14.18 ± 5.1% vs. 17.66 ± 8.88%, P<0.03, data expressed as mean ± SD and remained unchanged after 40 minutes. Significant differences were found in the motile sperm recovered after swim-up (control: 8.93×106 ± 9.52× 06vs. 17.20×106 ± 21.16×106, P<0.03, achieving all of the tested samples a desirable threshold value for artificial insemination outcome, while adding pentoxifylline increased the number of recovered sperm after swim-up in 60% of the studied cases. No synergism between two treatments could be determined. Conclusion We propose a new physiological tool to artificially improve insemination. The discussion opens windows to investigate unknown pathways involved in sperm ca- pacitation and gives innovative arguments to better understand infertility mechanisms.

  14. Endocannabinoids and Human Sperm Cells

    Directory of Open Access Journals (Sweden)

    Giovanna Zolese

    2010-10-01

    Full Text Available N-acylethanolamides (NAEs are naturally occurring signaling lipids consisting of amides and esters of long-chain polyunsaturated fatty acids. Usually they are present in a very small amounts in many mammalian tissues and cells, including human reproductive tracts and fluids. Recently, the presence of N-arachidonoylethanolamide (anandamide, AEA, the most characterised member of endocannabinoids, and its congeners palmitoylethanolamide (PEA and oleylethanolamide (OEA in seminal plasma, oviductal fluid, and follicular fluids was demonstrated. AEA has been shown to bind not only type-1 (CB1 and type-2 (CB2 cannabinoid receptors, but also type-1 vanilloid receptor (TRPV1, while PEA and OEA are inactive with respect to classical cannabinoid CB1 and CB2 but activate TRPV1 or peroxisome proliferator activate receptors (PPARs. This review concerns the most recent experimental data on PEA and OEA, endocannabinoid-like molecules which appear to exert their action exclusively on sperm cells with altered features, such as membrane characteristics and kinematic parameters. Their beneficial effects on these cells could suggest a possible pharmacological use of PEA and OEA on patients affected by some forms of idiopathic infertility.

  15. The future of competitions

    DEFF Research Database (Denmark)

    Bates, Gary; Jensen, Boris Brorman; Miessen, Markus

    2010-01-01

    We wanted to explore the potential of the competition. The question we asked ourselves was if the competition can generate new, relevant and critical ideas within architecture? We organized an idea competition about the architectural competition.......We wanted to explore the potential of the competition. The question we asked ourselves was if the competition can generate new, relevant and critical ideas within architecture? We organized an idea competition about the architectural competition....

  16. Sexual competition in an acanthocephalan parasite of fish.

    Science.gov (United States)

    Sasal, P; Jobet, E; Faliex, E; Morand, S

    2000-01-01

    Acanthocephalans are polygamous parasites of vertebrates and some species are known to aggregate in sexual congress to mate. Such a reproductive behaviour could lead to male-male competition for access to females and could have consequences for sexual selection. We dissected 87 gobiid fish, Gobius bucchichii, harbouring 891 acanthocephalans, Acanthocephaloides propinquus. The parasites were sexed and their body sizes were measured. Testicular volume was also evaluated in 82 males in order to establish their phenotypic sexual investment in relation to the estimated sex ratio. We found that parasite intensity (i.e. the number of individuals/fish) was not correlated with fish size, but that parasite size was significantly related to host size. Our results showed that there was a significant relationship between the mean female body size and their number within one host. We found that when the percentage of male parasites in a host increased, presumably increasing male-male competition for access to females, males had a larger testicular volume. We discuss these results in terms of energy allocation, sexual and sperm competition. We conclude that competition for space should be less important for males than competition for access to females. Moreover, increasing testis size should confer advantages to males especially for their reproductive success when sperm competition occurs.

  17. Analysis of sperm quality in recombinant inbred mouse strains: correlation of sperm head shape with sperm abnormalities and with the incidence of supplementary spermatozoa in the perivitelline space.

    Science.gov (United States)

    Krzanowska, H; Styrna, J; Wabik-Sliz, B

    1995-07-01

    Recombinant inbred strains were developed from reciprocal crosses between two inbred strains of mice (CBA and KE) differing in sperm head shape, proportion of normal sperm heads (CBA, 95%; KE, 78%) and fertilization efficiency (CBA, 100% of fertilized ova; KE, 72%), to determine whether the indices of sperm morphology and function were correlated. The following parameters were analysed in recombinant inbred and progenitor strains: index of sperm head shape (head width in the middle of its length/head length), percentage of abnormal sperm heads, percentage of spermatozoa with progressive movements, efficiency of penetration of hyaluronic acid polymer (Sperm Select) and percentage of fertilized ova after mating males from the tested strains with females from an outbred stock. For each investigated character, recombinant inbred strains, recombinant inbred EXCB and CBXE, could be divided into at least three categories: KE-like, CBA-like and intermediate, suggesting that in each case a minimum of two genes was involved. Recombinant strains derived from the reciprocal crosses of progenitor strains differed only with respect to the proportion of abnormal sperm heads, showing the involvement of the Y chromosome in determining this character. Penetration into Sperm Select was significantly correlated both with fertilization efficiency and sperm motility, while correlation with the proportion of normal spermatozoa did not reach the level of significance. However, there was a significant negative correlation of both sperm abnormalities and the incidence of supplementary spermatozoa in the perivitelline space with the index of sperm head shape.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Psychosocial counselling of identifiable sperm donors.

    Science.gov (United States)

    Visser, M; Mochtar, M H; de Melker, A A; van der Veen, F; Repping, S; Gerrits, T

    2016-05-01

    What do identifiable sperm donors feel about psychosocial counselling? Identifiable sperm donors found it important that psychosocial counselling focused on emotional consequences and on rules and regulations and they expected to have access to psychosocial counselling at the time that donor-offspring actually sought contact. Most studies on sperm donors are on anonymous donors and focus on recruitment, financial compensation, anonymity and motivations. There is limited knowledge on the value that identifiable sperm donors place on psychosocial counselling and what their needs are in this respect. We performed a qualitative study from March until June 2014 with 25 identifiable sperm donors, who were or had been a donor at the Centre for Reproductive Medicine of the Academic Medical Centre in Amsterdam any time between 1989 and 2014. We held semi-structured in-depth interviews with identifiable sperm donors with an average age of 44 years. The interviews were fully transcribed and analysed using the constant comparative method of grounded theory. Twelve out of 15 donors (former donors ITALIC! n = 8, active donors ITALIC! n = 7) who had received a counselling session during their intake procedure found it important that they had been able to talk about issues such as the emotional consequences of donation, disclosure to their own children, family and friends, future contact with donor-offspring and rules and regulations. Of the 10 former donors who had received no counselling session, 8 had regretted the lack of intensive counselling. In the years following their donation, most donors simply wanted to know how many offspring had been born using their sperm and had no need for further counselling. Nevertheless, they frequently mentioned that they were concerned about the well-being of 'their' offspring. In addition, they would value the availability of psychosocial counselling in the event that donor-offspring actually sought contact. A limitation of our study is its

  19. Sperm Donation and the Right to Privacy.

    Science.gov (United States)

    Hallich, Oliver

    2017-07-01

    Sperm donation is an increasingly common method of assisted reproduction. In the debate on sperm donation, the right to privacy - construed as a right that refers to the limits of the realm of information to which others have access - plays a pivotal role with regard to two questions. The first question is whether the sperm donor's right to privacy implies his right to retain his anonymity, the second is whether the gamete recipients' right to privacy entitles them to withhold information about the circumstances of their conception from their donor-conceived offspring. In this contribution, I tackle these two interrelated questions. In part (1), I defend the view that there is a prima facie right of sperm donors to remain anonymous. Part (2) widens the perspective by taking into consideration the welfare of donor-conceived offspring. I argue that anonymity may harm the child only if the gametes' recipients decide to disclose information about the circumstances of her birth to the child. Non-disclosure of these circumstances, however, is morally problematic because it may not necessarily harm, but wrong the child. In section (3), I attempt to rebut some arguments in defense of non-disclosure. In part (4), I defend the view that the best practice of sperm donation would be 'direct donation', i.e. that the identity of the donor is known from the time of conception. Part (5) concludes.

  20. Short communication Sperm DNA damage in relation to lipid ...

    African Journals Online (AJOL)

    Leyland Fraser

    2017-03-08

    LPO) and sperm DNA damage following freezing-thawing of boar semen in different extenders. The comet assay was used to measure the extent of sperm DNA damage in a cryoprotectant-free extender or in cryoprotectant-based ...

  1. Sperm viability staining in ecology and evolution: potential pitfalls

    DEFF Research Database (Denmark)

    Holman, Luke

    2009-01-01

    The causes and consequences of variation in sperm quality, survival and ageing are active areas of research in ecology and evolution. In order to address these topics, many recent studies have measured sperm viability using fluorescent staining. Although sperm viability staining has produced...... a number of interesting results, it has some potential pitfalls that have rarely been discussed. In the present paper, I review the major findings of ecology and evolution studies employing sperm viability staining and outline the method's principle limitations. The key problem is that the viability assay...... may itself kill sperm, which is likely to confound many common experimental designs in addition to producing artificially low estimates of sperm viability. I further suggest that sperm number should be routinely measured in sperm viability studies, as it may be an important but overlooked source...

  2. Prudent sperm use by leaf-cutter ant queens

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Dreier, Stéphanie Agnès Jeanine

    2009-01-01

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps......), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm...... cells, and this sperm must remain viable throughout the years of storage. Queens should also be under strong selection to use stored sperm prudently when fertilizing eggs. We used the leaf-cutter ant Atta colombica to investigate the dynamics of sperm use during egg fertilization. We show that queens...

  3. Pulmonary exposure to carbonaceous nanomaterials and sperm quality

    DEFF Research Database (Denmark)

    Skovmand, Astrid; Lauvas, Anna Jacobsen; Christensen, Preben

    2018-01-01

    inflammation is a potential modulator of endocrine function. The aim of this study was to investigate the effects of pulmonary exposure to carbonaceous nanomaterials on sperm quality parameters in an experimental mouse model.Methods: Effects on sperm quality after pulmonary inflammation induced by carbonaceous....... Pulmonary inflammation was determined by differential cell count in bronchoalveolar lavage fluid. Epididymal sperm concentration and motility were measured by computer-assisted sperm analysis. Epididymal sperm viability and morphological abnormalities were assessed manually using Hoechst 33,342/PI...... flourescent and Spermac staining, respectively. Epididymal sperm were assessed with regard to sperm DNA integrity (damage). Daily sperm production was measured in the testis, and testosterone levels were measured in blood plasma by ELISA.Results: Neutrophil numbers in the bronchoalveolar fluid showed...

  4. Gulf of Mexico sperm whale photo-ID catalog

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photo-identification data on sperm whales occupying the north central Gulf of Mexico have been collected during vessel surveys. Photographs of sperm whales are taken...

  5. Intracytoplasmic sperm injection (ICSI) and chromosomally abnormal spermatozoa

    NARCIS (Netherlands)

    P.A. in 't Veld; F.J.M. Broekmans (Frank); H.F. de France; P.L. Pearson; M.H. Pieters; R.J. van Kooij

    1997-01-01

    textabstractAn infertile couple was referred for intracytoplasmic sperm injection (ICSI) because of primary infertility and oligoasthenoteratozoospermia (OAT) in the male. It was observed that although the sperm cells presented with an unusual head size and multiple

  6. Structure and evolution of the sea star egg receptor for sperm bindin.

    Science.gov (United States)

    Hart, Michael W

    2013-04-01

    Selection on coevolving sperm- and egg-recognition molecules is a potent engine of population divergence leading to reproductive isolation and speciation. The study of receptor-ligand pairs can reveal co-evolution of male- and female-expressed genes or differences between their evolution in response to selective factors such as sperm competition and sexual conflict. Phylogeographical studies of these patterns have been limited by targeted gene methods that favour short protein-coding sequences amplifiable by PCR. Here, I use high-throughput transcriptomic methods to characterize the structure and divergence of full-length coding sequences for the gene encoding the protein component of a large complex egg surface glycopeptide receptor for the sperm acrosomal protein bindin from the sea star Patiria miniata. I used a simple but effective method for resolving nucleotide polymorphisms into haplotypes for phylogeny-based analyses of selection. The protein domain organization of sea star egg bindin receptor (EBR1) was similar to sea urchins and included a pair of protein-recognition domains plus a series of tandem repeat domains of two types. Two populations separated by a well-characterized phylogeographical break included lineages of EBR1 alleles under positive selection at several codons (similar to selection on sperm bindin in the same populations). However, these populations shared the same alleles that were under selection for amino acid differences at multiple codons (unlike the pattern of selection for population divergence in sperm bindin). The significance of positively selected EBR1 domains and alleles could be tested in functional analyses of fertilization rates associated with EBR1 (and bindin) polymorphisms. © 2013 Blackwell Publishing Ltd.

  7. Does breastfeeding influence future sperm quality and reproductive hormones?

    DEFF Research Database (Denmark)

    Laustsen, J M; Jensen, M S; Thulstrup, Ane Marie

    2011-01-01

    was not statistically significantly associated with sperm concentration, total sperm count, sperm motility or morphology, oligozoospermia, follicle-stimulating hormone, inhibin B, luteinizing hormone, sex hormone-binding globulin (SHBG), the calculated level of free testosterone, free oestradiol, the free testosterone...... testosterone nor free oestradiol was different between the two groups. This study shows no association between breastfeeding and sperm quality or reproductive hormones and a strong association is unlikely. A larger study would be needed to detect more subtle effects....

  8. Study of sperm proteins in different mammalian species

    OpenAIRE

    Pohlová, Alžběta

    2016-01-01

    Reproduction is an essential feature of all animals and a fundamental step to produce new generations. Study of sperm proteins is crucial for understanding of the sperm-egg recognition. We searched out sperm surface proteins involving in the zona pellucida (ZP) binding and studied whether these proteins are preserved throughout mammalian species. Indirect immunofluorescent technique was used to test a panel of monoclonal antibodies prepared against boar sperm surface proteins on spermatozoa o...

  9. Winning a competition predicts dishonest behavior.

    Science.gov (United States)

    Schurr, Amos; Ritov, Ilana

    2016-02-16

    Winning a competition engenders subsequent unrelated unethical behavior. Five studies reveal that after a competition has taken place winners behave more dishonestly than competition losers. Studies 1 and 2 demonstrate that winning a competition increases the likelihood of winners to steal money from their counterparts in a subsequent unrelated task. Studies 3a and 3b demonstrate that the effect holds only when winning means performing better than others (i.e., determined in reference to others) but not when success is determined by chance or in reference to a personal goal. Finally, study 4 demonstrates that a possible mechanism underlying the effect is an enhanced sense of entitlement among competition winners.

  10. Sperm retrieval outcomes with microdissection testicular sperm extraction (micro-TESE) in men with cryptozoospermia.

    Science.gov (United States)

    Alrabeeah, K; Wachter, A; Phillips, S; Cohen, B; Al-Hathal, N; Zini, A

    2015-05-01

    Several studies support of the use of testicular rather than ejaculated spermatozoa for intracytoplasmic sperm injection (ICSI) in couples with virtual azoospermia or cryptozoospermia, although this approach remains controversial. We sought to evaluate sperm retrieval outcomes with microdissection testicular sperm extraction (micro-TESE) in men with cryptozoospermia. We conducted a retrospective study of 24 consecutive micro-TESEs in men with cryptozoospermia. We also evaluated the outcomes of seven consecutive TESAs (testicular sperm aspiration) in cryptozoospermic men during the same time period (January 2007 and September 2014). Micro-TESE and TESA were performed on the day prior to ICSI. Final assessment of sperm recovery (reported on the day of ICSI) was recorded as (i) successful (available spermatozoa for ICSI) or (ii) unsuccessful (no spermatozoa for ICSI). The decision to perform a unilateral or bilateral micro-TESE was guided by the intra-operative evaluation of sperm recovery from the first testicle. A unilateral procedure was performed in 87.5% (21/24) and 57% (4/7) of the micro-TESE and TESA cohorts, respectively. Sperm recovery was successful in 96% (23/24) of the men who underwent micro-TESE and 43% (3/7) of the men who underwent TESA (p TESE and TESA groups were comparable [33% (6/18) and 50% (1/2), respectively]. The data indicate that micro-TESE is a highly successful sperm retrieval technique for men with cryptozoospermia and few of these men will require a bilateral procedure. Moreover, sperm retrieval rates are higher with micro-TESE than TESA in this group of men. © 2015 American Society of Andrology and European Academy of Andrology.

  11. The Effect of Different Foam Concentrations on Sperm Motility in Japanese Quail

    Directory of Open Access Journals (Sweden)

    Avishek Biswas

    2010-01-01

    Full Text Available A study was conducted to determine the effect of foam extract on sperm motility in the male Japanese quail (Coturnix coturnix japonica. Adult male quails (<12 weeks of heavy body weight strain were housed in individual cages and divided into 5 groups according to the size of their cloacal glands. The data indicated that the size of the cloacal gland was positively correlated with the frequency of foam secretion and total foam production. One gram of freshly collected clean foam was mixed with 1.0 mL of normal saline and homogenized for 10 minutes. After centrifugation at 35 000 rpm, the supernatant was used as 100% foam extract. The extract was diluted to 1:40, 1:20, 1:10, and 1:4 with normal saline to produce 2.5, 5.0, 10, and 25% foam extracts, respectively. 5% foam extract enhanced sperm survival at room temperature (30°–35°C for 2 to 3 hrs, whereas higher concentrations (10% and above suppressed sperm motility. From this study, it may be concluded that foam secretion and quantity of foam are directly proportional to the size of the cloacal gland and that the foam enhances and prolongs sperm motility, in vitro at an optimum concentration of 5%.

  12. Sperm cell surface dynamics during activation and fertilization

    NARCIS (Netherlands)

    Boerke, A.|info:eu-repo/dai/nl/304822922

    2013-01-01

    Before the sperm cell can reach the oocyte it needs to be activated and to undergo a series of preparative steps. The sperm surface dynamics was studied in relation to this activation process and the modifications and removal of sperm surface components havebeen investigated. Bicarbonate-induced

  13. Evolutionary genetics and ecology of sperm-dependent parthenogenesis

    NARCIS (Netherlands)

    Beukeboom, L.W.; Vrijenhoek, R.C.

    1998-01-01

    Sperm-dependent (or pseudogamous) forms of parthenogenetic reproduction occur in a wide variety of animals. Inheritance is typically clonal and matroclinous (of female descent), but sperm are needed to initiate normal development. As opposed to true parthenogenesis (i.e., sperm-independent

  14. Effect of 4-nonylphenol on the sperm dynamic parameters ...

    African Journals Online (AJOL)

    4-Nonylphenol (NP) is a compound that causes endocrine disruption and affects sperm quality of mammals and fish. However, the effects of NP on the sperm and fertilization rate of amphibians remain unknown. This study investigates the in vivo and in vitro effects of NP on the sperm dynamic parameters and fertilization ...

  15. Sperm storage and duration of fertility in female ostriches ( Struthio ...

    African Journals Online (AJOL)

    , the duration of sperm storage and the fertile period following separation of sexes were investigated by egg break-out and by counting the sperm in the perivitelline membrane (spermOPVL) above the germinal disc (GD) region. Fertilisation ...

  16. LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY

    Science.gov (United States)

    LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY. AE Lavers*1, GR Klinefelter2, DW Hamilton1, KP Roberts1, 1University of Minnesota, Minneapolis, MN and 2US EPA, Research Triangle Park, NC. SP22 is a sperm membrane protein that has been implicated in sperm function d...

  17. Sperm DNA fragmentation, recurrent implantation failure and recurrent miscarriage

    Directory of Open Access Journals (Sweden)

    Carol Coughlan

    2015-01-01

    Full Text Available Evidence is increasing that the integrity of sperm DNA may also be related to implantation failure and recurrent miscarriage (RM. To investigate this, the sperm DNA fragmentation in partners of 35 women with recurrent implantation failure (RIF following in vitro fertilization, 16 women diagnosed with RM and seven recent fathers (control were examined. Sperm were examined pre- and post-density centrifugation by the sperm chromatin dispersion (SCD test and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL assay. There were no significant differences in the age of either partner or sperm concentration, motility or morphology between three groups. Moreover, there were no obvious differences in sperm DNA fragmentation measured by either test. However, whilst on average sperm DNA fragmentation in all groups was statistically lower in prepared sperm when measured by the SCD test, this was not seen with the results from the TUNEL assay. These results do not support the hypothesis that sperm DNA fragmentation is an important cause of RIF or RM, or that sperm DNA integrity testing has value in such patients. It also highlights significant differences between test methodologies and sperm preparation methods in interpreting the data from sperm DNA fragmentation tests.

  18. Effect of Cobalt on Sperm Motility in an Endangered Trout Species, Salmo coruhensis.

    Science.gov (United States)

    Kocabaş, Mehmet; Kutluyer, Filiz

    2017-12-01

    Experiments were designed to examine the in vitro effect of cobalt on sperm motility of the endangered trout species (Salmo coruhensis). Sperm samples were diluted in an immobilizing solution, and activated in a motility-activation solution that was supplemented with cobalt at concentrations of 1, 10, 100 and 1000 mg/L. The percentage of motile sperm and duration of motility were determined. Cobalt concentrations of 1-100 mg/L had a positive effect on the percentage of motile sperm and duration of motility compared to the control group, while a concentration of 1000 mg/L resulted in decreases in these parameters (p cobalt concentrations of 0, 1, 10, 100 and 1000 mg/L were 83.33% ± 0.25%, 88.33% ± 0.34%, 89.00% ± 0.57%, 90.00% ± 0.87% and 42.50% ± 0.45%, respectively; and the time durations over which the sperm remained motile were 72.00 ± 0.63, 74.83 ± 0.28, 77.40 ± 0.47, 81.14 ± 0.78, and 50.25 ± 0.67 s, respectively. This study has shown that sperm motility and duration were significantly enhanced (p cobalt concentrations of 1, 10 and 100 mg/L, relative to controls, and significantly decreased at 1000 mg/L.

  19. Thinking though eggs, sperm and embryos- diffractive readings at the fertility clinic and sperm bank

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    questions may an analytical starting point in eggs, sperm and embryos, enable me to ask, and what diffractive stories of creation can I tell? These questions not only intrigue me, because I am deeply fascinated about new creation stories that may be told when assisted reproductive technologies are at use...... stories are told about egg, sperm and embryos (Adrian 2006), my current work has moved to look at negotiations of ethical borders and boundaries in relation to globalization of Danish donor sperm. This move in research questions is not only empirically based. It is also a shift indebted to my...

  20. Posttesticular sperm maturation, infertility, and hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Marjorie Whitfield

    2015-01-01

    Full Text Available Cholesterol is a key molecule in the mammalian physiology of especial particular importance for the reproductive system as it is the common precursor for steroid hormone synthesis. Cholesterol is also a recognized modulator of sperm functions, not only at the level of gametogenesis. Cholesterol homeostasis regulation is crucial for posttesticular sperm maturation, and imbalanced cholesterol levels may particularly affect these posttesticular events. Metabolic lipid disorders (dyslipidemia affect male fertility but are most of the time studied from the angle of endocrine/testicular consequences. This review will focus on the deleterious effects of a particular dyslipidemia, i.e., hypercholesterolemia, on posttesticular maturation of mammalian spermatozoa.

  1. Involvement of opsins in mammalian sperm thermotaxis

    Science.gov (United States)

    Pérez-Cerezales, Serafín; Boryshpolets, Sergii; Afanzar, Oshri; Brandis, Alexander; Nevo, Reinat; Kiss, Vladimir; Eisenbach, Michael

    2015-01-01

    A unique characteristic of mammalian sperm thermotaxis is extreme temperature sensitivity, manifested by the capacity of spermatozoa to respond to temperature changes of functional approaches that opsins are present in human and mouse spermatozoa at specific sites, which depend on the species and the opsin type, and that they are involved in sperm thermotaxis via two signalling pathways—the phospholipase C and the cyclic-nucleotide pathways. Our results suggest that, depending on the context and the tissue, mammalian opsins act not only as photosensors but also as thermosensors. PMID:26537127

  2. Fate of the sperm mitochondria, and the incorporation, conversion, and disassembly of the sperm tail structures during bovine fertilization.

    Science.gov (United States)

    Sutovsky, P; Navara, C S; Schatten, G

    1996-12-01

    Sperm incorporation and the conversion of the sperm-derived components into zygotic structures during in vitro fertilization of bovine oocytes was explored by combining ultrastructural studies with observations of the fertilizing sperm tagged with a mitochondrion-specific vital dye MitoTracker green FM. The zygotes fertilized by the MitoTracker-labeled sperm were fixed at various times after fertilization and then processed for immunocytochemistry to examine the distribution of DNA, microtubules, and sperm tail components, including the fibrous sheath and axonemal microtubules. We show here that the complete incorporation of the sperm, but not sperm-oocyte binding and oocyte activation, depends upon the integrity of oocyte microfilaments and is inhibited by the microfilament disrupter cytochalasin B. After sperm incorporation, the mitochondria are displaced from the sperm's connecting piece, and the sperm centriole is exposed to the egg cytoplasm. This event is followed by the formation of the microtubule-based sperm aster, which is responsible for the union of male and female pronuclei. Concomitantly, the major structure of the sperm principal piece, the fibrous sheath, disappears. After the first mitosis, the compact mitochondrial sheath can be seen in one of the blastomeres. An aggregate of the sperm mitochondria is observed at the entry of the second mitosis, although they remain in the vicinity of the nucleus and can later be seen at one pole of the metaphase spindle. The mitochondrial cluster is occasionally found in one of the blastomeres in the early-stage four-cell embryos, but it is no longer detected by the beginning of the third mitotic cycle. These data suggest that the disassembly of the sperm tail during bovine fertilization occurs as a series of precisely orchestrated events involving the destruction (fibrous sheath and mitochondrial sheath) and transformation (DNA, sperm centriole) of particular sperm structures into zygotic and embryonic

  3. Effect of transfection and co-incubation of bovine sperm with exogenous DNA on sperm quality and functional parameters for its use in sperm-mediated gene transfer.

    Science.gov (United States)

    Arias, María Elena; Sánchez-Villalba, Esther; Delgado, Andrea; Felmer, Ricardo

    2017-02-01

    Sperm-mediated gene transfer (SMGT) is based on the capacity of sperm to bind exogenous DNA and transfer it into the oocyte during fertilization. In bovines, the progress of this technology has been slow due to the poor reproducibility and efficiency of the production of transgenic embryos. The aim of the present study was to evaluate the effects of different sperm transfection systems on the quality and functional parameters of sperm. Additionally, the ability of sperm to bind and incorporate exogenous DNA was assessed. These analyses were carried out by flow cytometry and confocal fluorescence microscopy, and motility parameters were also evaluated by computer-assisted sperm analysis (CASA). Transfection was carried out using complexes of plasmid DNA with Lipofectamine, SuperFect and TurboFect for 0.5, 1, 2 or 4 h. The results showed that all of the transfection treatments promoted sperm binding and incorporation of exogenous DNA, similar to sperm incorporation of DNA alone, without affecting the viability. Nevertheless, the treatments and incubation times significantly affected the motility parameters, although no effect on the integrity of DNA or the levels of reactive oxygen species (ROS) was observed. Additionally, we observed that transfection using SuperFect and TurboFect negatively affected the acrosome integrity, and TurboFect affected the mitochondrial membrane potential of sperm. In conclusion, we demonstrated binding and incorporation of exogenous DNA by sperm after transfection and confirmed the capacity of sperm to spontaneously incorporate exogenous DNA. These findings will allow the establishment of the most appropriate method [intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF)] of generating transgenic embryos via SMGT based on the fertilization capacity of transfected sperm.

  4. The maintenance of sperm variability: context-dependent selection on sperm morphology in a broadcast spawning invertebrate.

    Science.gov (United States)

    Johnson, Darren W; Monro, Keyne; Marshall, Dustin J

    2013-05-01

    Why are sperm so variable despite having a singular, critical function and an intimate relationship with fitness? A key to understanding the evolution of sperm morphology is identifying which traits enable sperm to be successful fertilizers. Several sperm traits (e.g., tail length, overall size) are implicated in sperm performance, but the benefits of these traits are likely to be highly context dependent. Here, we examined phenotypic selection on sperm morphology of a broadcast spawning tube worm (Galeolaria gemineoa). We conducted laboratory experiments to measure the relationship between average sperm morphology and relative fertilization success across a range of sperm environments that were designed to approximate the range of sperm concentrations and ages encountered by eggs in nature. We found that the strength and form of multivariate selection varied substantially across our environmental gradients. Sperm with long tails and small heads were favored in high-concentration environments, whereas sperm with long heads were favored at low concentrations and old ages. We suggest variation in the local fertilization environment and resulting differences in selection can preserve variability in sperm morphology both within and among males. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

  5. A Human Lectin Microarray for Sperm Surface Glycosylation Analysis *

    Science.gov (United States)

    Sun, Yangyang; Cheng, Li; Gu, Yihua; Xin, Aijie; Wu, Bin; Zhou, Shumin; Guo, Shujuan; Liu, Yin; Diao, Hua; Shi, Huijuan; Wang, Guangyu; Tao, Sheng-ce

    2016-01-01

    Glycosylation is one of the most abundant and functionally important protein post-translational modifications. As such, technology for efficient glycosylation analysis is in high demand. Lectin microarrays are a powerful tool for such investigations and have been successfully applied for a variety of glycobiological studies. However, most of the current lectin microarrays are primarily constructed from plant lectins, which are not well suited for studies of human glycosylation because of the extreme complexity of human glycans. Herein, we constructed a human lectin microarray with 60 human lectin and lectin-like proteins. All of the lectins and lectin-like proteins were purified from yeast, and most showed binding to human glycans. To demonstrate the applicability of the human lectin microarray, human sperm were probed on the microarray and strong bindings were observed for several lectins, including galectin-1, 7, 8, GalNAc-T6, and ERGIC-53 (LMAN1). These bindings were validated by flow cytometry and fluorescence immunostaining. Further, mass spectrometry analysis showed that galectin-1 binds several membrane-associated proteins including heat shock protein 90. Finally, functional assays showed that binding of galectin-8 could significantly enhance the acrosome reaction within human sperms. To our knowledge, this is the first construction of a human lectin microarray, and we anticipate it will find wide use for a range of human or mammalian studies, alone or in combination with plant lectin microarrays. PMID:27364157

  6. Power market competition

    International Nuclear Information System (INIS)

    Kelly, J.

    1998-01-01

    In the Unites States the prospect of greater competition in wholesale power market was immediately eclipsed by talk of retail competition. Attempts to move to retail competition have been costly and complex. Prudent public policy and economic analyses suggest that retail competition not be implemented until it can first be demonstrated that effective competition exists in wholesale power markets [it

  7. Lunabotics Mining Competition

    Science.gov (United States)

    Mueller, Rob; Murphy, Gloria

    2010-01-01

    This slide presentation describes a competition to design a lunar robot (lunabot) that can be controlled either remotely or autonomously, isolated from the operator, and is designed to mine a lunar aggregate simulant. The competition is part of a systems engineering curriculum. The 2010 competition winners in five areas of the competition were acknowledged, and the 2011 competition was announced.

  8. Immunological usefulness of semen manipulation for artificial insemination homologous (AIH) in subjects with antisperm antibodies bound to sperm surface.

    Science.gov (United States)

    Lenzi, A; Gandini, L; Claroni, F; Lombardo, F; Morrone, S; Dondero, F

    1988-01-01

    The authors report trials carried out in the preparation of semen for homologous artificial insemination in subjects with antisperm autoantibodies. The tests have demonstrated that swim-up is not able to select spermatozoa free of antibodies bound to the sperm surface. All the experiments of migration, dilution, antigenic competition and cryoconservation, carried out to evaluate the theoretical possibility of a better recovery of non "immunologically compromised" spermatozoa, have confirmed such negative results both with the Immunobead Test and Cytofluorimetric analysis.

  9. Competitive spirit

    Science.gov (United States)

    2000-01-01

    Leicester University will host the 65 international teams of students who will assemble in July for this year's International Physics Olympiad . The last time the Olympiad came to the UK was in 1986 in London, and it was the notable enthusiasm of the Leicester Physics and Astronomy department which persuaded the Olympiad Committee to give them the chance of organizing the prestigious event. The students taking part from all over the world are studying physics at A-level or an equivalent standard and they will take part in an intellectual marathon of theoretical and practical examinations. Each national team comprises five students selected from three rounds of competition and the teams will receive an official welcome from the city, as well as opportunities to visit some of the important educational and cultural centres of the surrounding region. The finalists will also be able to test their skills and initiative at the Challenger Learning Centre, which forms part of Leicester's new National Space Science Centre. Specific information on the event can be found on the Olympiad-2000 website at www.star.le.ac.uk/IphO-2000 . The Rudolf Ortvay problem solving contest in physics, which takes place in November, is a tradition of Eötvös University in Budapest, Hungary. The competition was first opened to international participants in 1998, enabling students from universities around the world to show their knowledge, ingenuity, problem-solving skills and physical insight into problems that are far beyond routine level. The problems (30 - 35 each year) are chosen from different branches of theoretical as well as applied physics. They have varying levels of difficulty, and every contestant can send solutions for ten problems. The focus is not on school-level problem-solving routines but rather on the `physical' way of thinking, recognition of the heart of the problem and an appropriate choice of mathematics. The majority of the assigned problems are original, few having

  10. Effects of ocean warming and acidification on fertilization in the Antarctic echinoid Sterechinus neumayeri across a range of sperm concentrations.

    Science.gov (United States)

    Ho, M A; Price, C; King, C K; Virtue, P; Byrne, M

    2013-09-01

    The gametes of marine invertebrates are being spawned into an ocean that is simultaneously warming and decreasing in pH. Predicting the potential for interactive effects of these stressors on fertilization is difficult, especially for stenothermal polar invertebrates adapted to fertilization in cold, viscous water and, when decreased sperm availability may be an additional stressor. The impact of increased temperature (2-4 °C above ambient) and decreased pH (0.2-0.4 pH units below ambient) on fertilization in the Antarctic echinoid Sterechinus neumayeri across a range of sperm concentrations was investigated in cross-factorial experiments in context with near future ocean change projections. The high temperature treatment (+4 °C) was also used to assess thermal tolerance. Gametes from multiple males and females in replicate experiments were used to reflect the multiple spawner scenario in nature. For fertilization at low sperm density we tested three hypotheses, 1) increased temperature enhances fertilization success, 2) low pH reduces fertilization and, 3) due to the cold stenothermal physiology of S. neumayeri, temperature would be the more significant stressor. Temperature and sperm levels had a significant effect on fertilization, but decreased pH did not affect fertilization. Warming enhanced fertilization at the lowest sperm concentration tested likely through stimulation of sperm motility and reduced water viscosity. Our results indicate that fertilization in S. neumayeri, even at low sperm levels potentially found in nature, is resilient to near-future ocean warming and acidification. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Sperm proteasomes degrade sperm receptor on the egg zona pellucida during mammalian fertilization.

    Directory of Open Access Journals (Sweden)

    Shawn W Zimmerman

    Full Text Available Despite decades of research, the mechanism by which the fertilizing spermatozoon penetrates the mammalian vitelline membrane, the zona pellucida (ZP remains one of the unexplained fundamental events of human/mammalian development. Evidence has been accumulating in support of the 26S proteasome as a candidate for echinoderm, ascidian and mammalian egg coat lysin. Monitoring ZP protein degradation by sperm during fertilization is nearly impossible because those few spermatozoa that penetrate the ZP leave behind a virtually untraceable residue of degraded proteins. We have overcome this hurdle by designing an experimentally consistent in vitro system in which live boar spermatozoa are co-incubated with ZP-proteins (ZPP solubilized from porcine oocytes. Using this assay, mimicking sperm-egg interactions, we demonstrate that the sperm-borne proteasomes can degrade the sperm receptor protein ZPC. Upon coincubation with motile spermatozoa, the solubilized ZPP, which appear to be ubiquitinated, adhered to sperm acrosomal caps and induced acrosomal exocytosis/formation of the acrosomal shroud. The degradation of the sperm receptor protein ZPC was assessed by Western blotting band-densitometry and proteomics. A nearly identical pattern of sperm receptor degradation, evident already within the first 5 min of coincubation, was observed when the spermatozoa were replaced with the isolated, enzymatically active, sperm-derived proteasomes. ZPC degradation was blocked by proteasomal inhibitors and accelerated by ubiquitin-aldehyde(UBAL, a modified ubiquitin protein that stimulates proteasomal proteolysis. Such a degradation pattern of ZPC is consistent with in vitro fertilization studies, in which proteasomal inhibitors completely blocked fertilization, and UBAL increased fertilization and polyspermy rates. Preincubation of intact zona-enclosed ova with isolated active sperm proteasomes caused digestion, abrasions and loosening of the exposed zonae, and

  12. Improving sperm banking efficiency in endangered species through the use of a sperm selection method in brown bear (Ursus arctos) thawed sperm.

    Science.gov (United States)

    Anel-Lopez, L; Ortega-Ferrusola, C; Álvarez, M; Borragán, S; Chamorro, C; Peña, F J; Morrell, J; Anel, L; de Paz, P

    2017-06-26

    Sperm selection methods such as Single Layer Centrifugation (SLC) have been demonstrated to be a useful tool to improve the quality of sperm samples and therefore to increase the efficiency of other artificial reproductive techniques in several species. This procedure could help to improve the quality of genetic resource banks, which is essential for endangered species. In contrast, these sperm selection methods are optimized and focused on farm animals, where the recovery task is not as important as in endangered species because of their higher sperm availability. The aim of this study was to evaluate two centrifugation methods (300 x g/20 min and 600 x g/10 min) and three concentrations of SLC media (Androcoll-Bear -80, 65 and 50%) to optimise the procedure in order to recover as many sperm with the highest quality as possible. Sperm morphology could be important in the hydrodynamic relationship between the cell and centrifugation medium and thus the effect of sperm head morphometry on sperm yield and its hydrodynamic relationship were studied. The samples selected with Androcoll-Bear 65% showed a very good yield (53.1 ± 2.9) although the yield from Androcoll-Bear 80% was lower (19.3 ± 3.3). The latter showed higher values of motility than the control immediately after post-thawing selection. However, both concentrations of colloid (65 and 80%) showed higher values of viable sperm and viable sperm with intact acrosome than the control. After an incubation of 2 h at 37 °C, the samples from Androcoll-Bear 80% had higher kinematics and proportion of viable sperm with intact acrosome. In the morphometric analysis, the sperm selected by the Androcoll-Bear 80% showed a head with a bigger area which was more elongated than the sperm from other treatments. We conclude that sperm selection with Androcoll-Bear at either 65% or 80% is a suitable technique that allows a sperm population with better quality than the initial sample to be obtained. We recommend the

  13. Effect of sorafenib on sperm count and sperm motility in male Swiss albino mice

    Directory of Open Access Journals (Sweden)

    Surekha Devadasa Shetty

    2015-01-01

    Full Text Available The issue of male germ line mutagenesis and the effects on developmental defects in the next generation has become increasingly high profile over recent years. Mutagenic substance affects germinal cells in the testis. Since the cells are undergoing different phases of cell division and maturation, it is an ideal system to study the effect of chemotherapeutic agents. There are lacunae in the literature on the effect of sorafenib on gonadal function. With background, a study was planned to evaluate the effects of sorafenib on sperm count and sperm motility in male Swiss albino mice. Male Swiss albino mice were used for the study. The animals were segregated into control, positive control (PC and three treatment groups. PC received oral imatinib (100 mg/kg body weight and treatment groups received 25, 50, and 100 mg/kg body weight of sorafenib orally for 7 consecutive days at intervals of 24 h between two administrations. The control group remained in the home cage for an equal duration of time to match their corresponding treatment groups. The animals were sacrificed at the end of 1 st , 2 nd , 4 th , 5 th , 7 th , and 10 th weeks after the last exposure to drug, respectively. Sperm suspensions were prepared and introduced into a counting chamber. Total sperm count and motility were recorded. There was a significant decrease in sperm count and sperm motility by sorafenib which was comparable with the effect of PC imatinib. Sorafenib adversely affects sperm count and sperm motility which are reversible after discontinuation of treatment.

  14. Study of Sperm Parameters and Sperm Fertility in Mice were Exposed to Tamoxifen during Embryonic Development

    Directory of Open Access Journals (Sweden)

    J Soleimanirad

    2017-05-01

    Full Text Available Introduction: Tamoxifen is steroidal drug, which mainly treats breast cancer and also used to stimulate ovulation. The purpose of the present study was the evaluation of sperm parameters and fertility of mice whose mothers had received tamoxifen during pregnancy. Methods: In this study, 30 female and 15 male mice of NMRI were selected for mating. After mating female mice were randomly divided into two groups, the first group (control and second group (experimental. All of which contained 15 mice. From the day 13th day of pregnancy, experimental group has received tamoxifen with the dosage of 5 mg/kg for 7 days. After childbirth of the mated mice, male infants were selected. After reaching the age of puberty (6-8Weeks, adult mice were sacrificed by the cervical dislocation. After take sperm, sperm parameters (count, normality and motility, and sperm fertility was performed. In this study SPSS software and statistical t-test was used (p <0.001. Results: Studies showed that sperm parameters and sperm fertilization were significantly different. The number of sperm in the control group was 83.50±28.20 million, and in the experimental group was 60±14.14 million. There was a decrease in average sperm count in the experimental group compared with the control group (p <0.001. Our findings from in vitro fertilization culture media showed that embryos formation and oocyte disruption between control and experimental groups significantly different (p <0.001. Conclusion: The results showed that tamoxifen exposure during development can cause histological changes in the seminiferous tubules, which can lead to infertility.

  15. Microscopic analysis of MTT stained boar sperm cells

    Directory of Open Access Journals (Sweden)

    B.M. van den Berg

    2015-06-01

    Full Text Available The ability of sperm cells to develop colored formazan by reduction of MTT was used earlier to develop a spectrophotometric assay to determine the viability of sperm cells for several mammalian species. It was the objective of the present study to visualize microscopically the location of the formazan in boar sperm cells. The MTT staining process of boar sperm cells can be divided into a series of morphological events. Incubation of the sperm cells in the presence of MTT resulted after a few min in a diffuse staining of the midpiece of the sperm cells. Upon further incubation the staining of the midpiece became more intense, and gradually the formation of packed formazan granules became more visible. At the same time, a small formazan stained granule appeared medially on the sperm head, which increased in size during further incubation. After incubation for about 1 h the midpiece granules were intensely stained and more clearly distinct as granules, while aggregation of sperm cells occurred. Around 90% of the sperm cells showed these staining events. At the end of the staining the formazan granules have disappeared from both the sperm cells and medium, whereas formazan crystals appeared as thin crystal threads, that became heavily aggregated in the incubation medium. It was concluded that formazan is taken up by lipid droplets in the cytoplasm. Further, the use of the MTT assay to test for sperm viability should be regarded as a qualitative assay, whereas its practical use at artificial insemination (AI Stations is limited.

  16. Single bovine sperm sex typing by amelogenin nested PCR.

    Science.gov (United States)

    Colley, A; Buhr, M; Golovan, S P

    2008-10-01

    Sex-sorted bovine semen has become a valuable tool in animal production for sex preselection. Development of novel sperm sexing technologies, or evaluation of the quality of existing methods, often requires a single-sperm, sex-typing method that is reliable and easy to perform. In the present study, we report the development, validation, and application of a simple, reliable, and cost-effective method for single-sperm sex typing using nested polymerase chain reaction (PCR), based on the amelogenin gene. Several hundred single sperm were isolated using a simple manual technique, or a high-speed flow-sorter, and were successfully sex-typed using the amelogenin nested PCR. Based on the pooled results of individual sperm, there was no significant difference in the semen sex ratio of unsorted (44.6% X-sperm and 55.4% Y-sperm) or X/Y-sorted semen (91.4% X-sperm and 94.0% Y-sperm), as compared to the expected ratio in unsorted semen or the post-sorting reanalysis data, respectively. The amelogenin single-sperm sexing method was an adaptable, accurate, and reliable tool for single-sperm sex typing.

  17. The sperm of Hylodinae species (Anura, Leptodactylidae ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 31; Issue 3. The sperm of Hylodinae species (Anura, Leptodactylidae): Ultrastructural characteristics and their relevance to interspecific taxonomic relationships. O Aguiar-Jr A A Giaretta S M Recco-Pimentel. Articles Volume 31 Issue 3 September 2006 pp 379-388 ...

  18. Comparative evaluation of the sperm characteristics and ...

    African Journals Online (AJOL)

    Comparative evaluation of the sperm characteristics and morphology of adult Wistar rats fed either low or normal protein-energy diets and orally dosed with ... of adult Wistar rats orally dosed aqueous extracts of C. australis seed (LPSE and NPSE) and stem (LPST and NPST), 300mg of extract/kg body weight of rat/day, ...

  19. Exposures that may affect sperm DNA integrity

    DEFF Research Database (Denmark)

    Håkonsen, L B; Spano, M; Bonde, J P

    2012-01-01

    Prenatal lifestyle exposures are linked to alterations in conventional semen characteristics. Sperm DNA integrity is another marker of semen quality shown to be altered in mice prenatally exposed to chemicals. From a Danish pregnancy cohort established in 1984-1987, sons were selected for a follow...

  20. Comparative evaluation of the sperm characteristics and ...

    African Journals Online (AJOL)

    olayemitoyin

    Comparative evaluation of the sperm characteristics and morphology of adult Wistar rats fed either low or normal protein-energy diets and orally dosed with aqueous Cuscuta australis extracts. 1. Omirinde, J.O., *. 1. Ozegbe, P.C. and. 2. Oyeyemi, M.O.. Departments of 1Veterinary Anatomy and 2Veterinary Surgery and ...

  1. Psychosocial counselling in donor sperm treatment

    NARCIS (Netherlands)

    Visser, M.

    2018-01-01

    For decades, donor sperm treatment is offered to men and women to build a family. In daily life, parents, children and donors have to deal with the consequences of this treatment. The studies of this thesis show that there are gaps in knowledge about specialist psychosocial counselling and guidance

  2. Cryopreservation of mutton snapper ( Lutjanus analis sperm

    Directory of Open Access Journals (Sweden)

    EDUARDO G. SANCHES

    2013-09-01

    Full Text Available This study aimed to develop a protocol of semen cryopreservation of the mutton snapper Lutjanus analis. The interaction between three extenders ( pH 6.1; 7.8 and 8.2 , two concentrations of dimethyl sulfoxide ( DMSO, 5 and 10% and three cooling rates ( -90; -60 and -30°C.min−1 on the sperm motility rate and motility time were analyzed by a factorial experiment. A sample of 30 fishes ( 1,261 ± 449 g collected in the nature was kept in floating net cages. The semen was frozen by using cryogenic straws, in nitrogen vapour and transferred, later, to liquid nitrogen. Fertilization test was accomplished to evaluate the viability of the cryopreserved sperm. The highest sperm motility rate and motility time ( P < 0.05 was achieved by combining extender C ( pH 8.2 with DMSO ( 10% and cooling rate of -60°C.min−1 ( P < 0.05 . The use of cryopreserved sperm presented fertilization rates higher than 59% validating the present protocol for mutton snapper.

  3. Sperm Quality and Fertility Following Prolonged Immobilization ...

    African Journals Online (AJOL)

    Sperm Quality and Fertility Following Prolonged Immobilization Stress in Wistar Rats. ... All the females that were mated with the control males became pregnant and produced litters. On the ... These results therefore, confirm and expand existing literatures reporting impaired fertility following long-term exposure to stress.

  4. The relationship between acridine orange fluorescence of sperm nuclei and the fertilizing ability of human sperm.

    Science.gov (United States)

    Hoshi, K; Katayose, H; Yanagida, K; Kimura, Y; Sato, A

    1996-10-01

    To determine whether the outcome of IVF can be predicted by acridine orange (AO) nuclear fluorescence of sperm. Based on the fact that AO nuclear fluorescence color after acid treatment reflects maturity (green fluorescence) or immaturity (yellow to red fluorescence) of spermatozoa, the relationships between sperm maturity and the outcome of IVF, subzonal insemination, or intracytoplasmic sperm injection (ICSI) were investigated. The IVF program at the Obstetrics and Gynecology Hospital, Fukushima Medical College. Sixty-eight patients undergoing 68 IVF treatment cycles. Acridine orange fluorescence of sperm nuclei and successful oocyte fertilization. conventional semen parameters (sperm concentration and percentages of motile or morphologically normal spermatozoa in semen) did not correlate with the incidence of spermatozoa with green AO fluorescent (mature) nuclei. When > or = 50% of spermatozoa in semen samples exhibited green AO nuclear fluorescence, IVF was always successful. When green AO nuclear fluorescence was green AO fluorescent spermatozoa were able to bind efficiently human zona pellucida. When the incidence of green AO fluorescent spermatozoa was fertilized by ICSI. The spermatozoa which fertilized oocytes in vivo and in IVF were limited to those whose nuclei exhibited green AO fluorescence. Intracytoplasmic sperm injection may be the method of choice when the incidence of green AO nuclear fluorescence is low regardless of the results of semen analysis.

  5. Microsurgical and Percutaneous Epididymal Sperm Aspiration for Sperm Collection from Live Mice.

    Science.gov (United States)

    Boersma, Auke; Olszanska, Olga; Walter, Ingrid; Rülicke, Thomas

    2015-09-01

    Spermatozoa for in vitro fertilization of mouse oocytes and other methods of assisted reproduction typically are collected from the cauda epididymis of euthanized male mice. As an alternative to this terminal protocol, we developed and examined 2 methods for collecting sperm from anesthetized male mice without decreasing subsequent fertility: microsurgical epididymal sperm aspiration and, as a refinement, percutaneous epididymal sperm aspiration. Collected sperm was evaluated in terms of motility, concentration and in vitro fertilization ability. After recovery, both treated and untreated control male mice underwent in vivo fertility testing and subsequent histologic analysis of the treated male reproductive tract (epididymis and testis). In vitro fertilization using sperm recovered by the 2 collection methods was successfully achieved in all cases. The in vivo fertility test and the histologic analysis revealed no impairment of fertility and no permanent histologic alteration in the treated mice. Therefore, we recommend both techniques as simple and effective methods for recovering high-quality epididymal mouse sperm without having to euthanize fertile male mice.

  6. Effect of environmental pH on sperm kinematic characteristics

    DEFF Research Database (Denmark)

    Alipour, Hiva; Dardmeh, Fereshteh; Dissing, Marianne Charlotte

    2015-01-01

    Semen preparation medium have an important role in assisted reproduction techniques and their composition influences sperm binding and motility. Some studies have assessed the influence of pH on sperm kinetics. However, no study to date has assessed the effect of environmental pH on subtle...... differences in the details of the sperm movement (kinematics) of human sperm provided by computerized sperm analysis systems. This study was designed to assess the effect of two different media pH levels on kinematic parameters of the human sperm. Samples were prepared using the 40%/80% Pureception (Sage, USA....... Linearity and Wobble showed significant difference after 24 hours. This study demonstrated a difference in the sperm motion pattern and velocity in different environmental pH levels. Based on these findings, further investigations are required to elucidate knowledge about possible effect of marginal p...

  7. Sperm cells as vectors in the production of transgenic animals

    Energy Technology Data Exchange (ETDEWEB)

    Prince, R.M.

    1993-04-28

    Transgenic animals are used in industry and in biomedical research in order to provide in vivo experimental model systems. Sperm cells have been reported used as vectors in the production of transgenic animals before, however no approach has of yet proven to be successful. Fertilizing eggs with genetically modified sperm would be advantageous in that sperm are readily accessible and stable, and eggs can be fertilized by modified sperm cells in vivo. Recent elucidations regarding the unique manner of DNA packaging in sperm chromatin by protamines has provided us with the insight for developing a method of introducing foreign DNA into sperm which is likely to succeed where others have failed. We have developed a method for mimicking the in vivo system of sperm chromatin toroid subunits in vitro, concentrating these toroids, and fluorescent visualization. Our present work concerns development of a method to successfully deliver DNA across the cell membranes and into the nucleus.

  8. Response of midpiece vesicles on human sperm to osmotic stress

    DEFF Research Database (Denmark)

    Abraham-Peskir, Joanna V; Chantler, Eric; Uggerhøj, Erik

    2002-01-01

    BACKGROUND: We investigated the osmotic response of midpiece vesicles (MPV) on human sperm. METHODS: Light microscopy, transmission X-ray microscopy and computer-aided semen analysis was used to investigate sperm in normozoospermic semen from healthy donors, separated from semen and suspended...... in hyper- or hypo-osmotic solutions. RESULTS: The mean incidence of MPV-bearing sperm in semen was 31% (range 8-71; n = 47). MPV were morphologically different from cytoplasmic droplets. The incidence of MPV-bearing sperm in separated populations increased reversibly after washing in Sperm Preparation...... Medium but not after washing in seminal plasma. There was an inverse relationship between medium osmolality and both MPV-bearing sperm incidence and MPV diameter. However, initial osmolality in semen from different donors did not correlate with incidence of MPV-bearing sperm. Furthermore, a direct...

  9. Sperm storage induces an immunity cost in ants

    DEFF Research Database (Denmark)

    Baer, Boris; Armitage, Sophie A O; Boomsma, Jacobus J

    2006-01-01

    Ant queens are among the most long-lived insects known. They mate early in adult life and maintain millions of viable sperm in their sperm storage organ until they die many years later. Because they never re-mate, the reproductive success of queens is ultimately sperm-limited, but it is not known...... what selective forces determine the upper limit to sperm storage. Here we show that sperm storage carries a significant cost of reduced immunity during colony founding. Newly mated queens of the leaf-cutting ant Atta colombica upregulate their immune response shortly after completing their nest burrow......, probably as an adaptive response to a greater exposure to pathogens in the absence of grooming workers. However, the immune response nine days after colony founding is negatively correlated with the amount of sperm in the sperm storage organ, indicating that short-term survival is traded off against long...

  10. Competition, cooperation, and collective choice

    DEFF Research Database (Denmark)

    Markussen, Thomas; Reuben Paris, Ernesto Guillermo; Tyran, Jean-Robert Karl

    The ability of groups to implement efficiency-enhancing institutions is emerging as a central theme of research in economics. This paper explores voting on a scheme of intergroup competition which facilitates cooperation in a social dilemma situation. Experimental results show that the competitiv...

  11. Competition, cooperation, and collective choice

    DEFF Research Database (Denmark)

    Markussen, Thomas; Reuben Paris, Ernesto Guillermo; Tyran, Jean-Robert Karl

    2014-01-01

    The ability of groups to implement efficiency-enhancing institutions is emerging as a central theme of research in economics. This paper explores voting on a scheme of intergroup competition, which facilitates cooperation in a social dilemma situation. Experimental results show that the competiti...

  12. Second COSTECH annual national science and technological conference and exhibitions: Science, technology and innovation in enhancing competitiveness for socio-economic development

    International Nuclear Information System (INIS)

    2007-01-01

    The Government of the United Republic of Tanzania recognizes that science, technology and innovation (STI) are vital to our economic and social progress. In an increasingly globalised world, it is recognised that high levels of investment in research and innovation are essential, both for economic competitiveness and to yield innovations in areas such as agriculture, health, natural resources, environment and energy sectors and make tangible improvements to the quality of our life. The government also realizes the need to provide an enabling environment for competition and innovation which in turn creates pressure for improvements in efficiency, quality and productivity. The development of a knowledge economy is a key challenge that is facing Tanzania today. It is essential that the country strives to build a truly knowledge based society. Such a society will offer new opportunities for economic and social advancement. It is therefore important that for a knowledge translation and disseminations are created and strengthened. The context to this is that knowledge is the currency for development.(author)

  13. Maillard Conjugation of Sodium Alginate to Whey Protein for Enhanced Resistance to Surfactant-Induced Competitive Displacement from Air-Water Interfaces.

    Science.gov (United States)

    Cai, Bingqing; Saito, Anna; Ikeda, Shinya

    2018-01-24

    Whey protein adsorbed to an interface forms a viscoelastic interfacial film but is displaced competitively from the interface by a small-molecule surfactant added afterward. The present study evaluated the impact of the covalent conjugation of high- or low-molecular-weight sodium alginate (HA or LA) to whey protein isolate (WPI) via the Maillard reaction on the ability of whey protein to resist surfactant-induced competitive displacement from the air-water interface. Surfactant added after the pre-adsorption of conjugate to the interface increased surface pressure. At a given surface pressure, the WPI-LA conjugate showed a significantly higher interfacial area coverage and lower interfacial film thickness compared to those of the WPI-HA conjugate or unconjugated WPI. The addition of LA to the aqueous phase had little effect on the interfacial area and thickness of pre-adsorbed WPI. These results suggest the importance of the molecular weight of the polysaccharide moiety in determining interfacial properties of whey protein-alginate conjugates.

  14. Sperm flagellum volume determines freezability in red deer spermatozoa.

    Directory of Open Access Journals (Sweden)

    José Luis Ros-Santaella

    Full Text Available The factors affecting the inter-individual differences in sperm freezability is a major line of research in spermatology. Poor sperm freezability is mainly characterised by a low sperm velocity, which in turn is associated with low fertility rates in most animal species. Studies concerning the implications of sperm morphometry on freezability are quite limited, and most of them are based on sperm head size regardless of the structural parts of the flagellum, which provides sperm motility. Here, for the first time, we determined the volumes of the flagellum structures in fresh epididymal red deer spermatozoa using a stereological method under phase contrast microscopy. Sperm samples from thirty-three stags were frozen and classified as good freezers (GF or bad freezers (BF at two hours post-thawing using three sperm kinetic parameters which are strongly correlated with fertility in this species. Fourteen stags were clearly identified as GF, whereas nineteen were BF. No significant difference in sperm head size between the two groups was found. On the contrary, the GF exhibited a lower principal piece volume than the BF (6.13 µm3 vs 6.61 µm3, respectively, p = 0.006. The volume of the flagellum structures showed a strong negative relationship with post-thawing sperm velocity. For instance, the volume of the sperm principal piece was negatively correlated with sperm velocity at two hours post-thawing (r = -0.60; p<0.001. Our results clearly show that a higher volume of the sperm principal piece results in poor freezability, and highlights the key role of flagellum size in sperm cryopreservation success.

  15. Sperm antibody production in female sterility.

    Science.gov (United States)

    Mettler, L; Scheidel, P; Shirwani, D

    1974-01-01

    A review of the immunological implications in reproductive physiology is presented. Although attempts have been made to ascribe the antigenicity of semen to individual components, it has not been possible to isolate the human semen antigen responsible for infertility. In monkeys total ejaculates and seminal plasma have shown higher antigenicity than washed spermatozoa. In bulls some evidence of such antigens have been found in the seminal plasma. They are iron-binding proteins resembling lactoferrin. Most investigators have found no evidence for any participation of the ABO blood group antigens in cases of sterility. On the surface of human spermatozoa histo-incompatibility antigens have been detected. Transplantation antigens may be related to sterility. However, an immulogic tolerance of the maternal organism exists against the genetically foreign fetal tissue. Autoimmune spermagglutinating antibodies have been detected in the sera and in the seminal plasma of males with sterility. An obstruction of the seminal pathways may facilitate the production of such antibodies against retained sperm. Isoimmunity in females against seminal components has been shown in cases of sterility; however, fertile women have also been shown to have such conditions. In a group of infertile women spermagglutination activity was detected in 7.5% of cases. In another series of 46 cases with primary unexplained infertility agglutinating antibodies were found in 17.4%. Other investigators have also reported higher rates than the authors. The sperm immobilization test seems to be more sensitive than the agglutination test. No sera were found positive with both tests. With immunofluorescent techniques humoral sperm antibodies have been found to be the IgM and IgG fractions. Each acts on a different part of the spermatozoa. The only promising therapy against humoral sperm antibodies is avoidance of sperm contact over a long period of time. Reported results have been conflicting. Cortisone

  16. A new approach to sperm preservation based on bioenergetic theory.

    Science.gov (United States)

    Froman, D P; Feltmann, A J

    2010-04-01

    To date, attempts to preserve chicken sperm have been based on a trial-and-error experimental approach. The present work outlines the development of an alternative approach based on empiricism and bioenergetic theory. In previous work, we found fowl sperm motility to be dependent on mitochondrial calcium cycling, phospholipase A(2), and long-chain fatty acids as an endogenous energy source. It is noteworthy that fowl sperm reside within the sperm storage tubules (SST) of the oviduct over an interval of days to weeks after insemination. In this regard, a model for in vivo sperm storage was developed and tested in additional previous research. Sperm penetration of the SST, sperm residence within the SST, and sperm egress from the SST can be explained in terms mitochondrial function. Understanding sperm function and longevity in terms of bioenergetics presented the possibility that sperm could be inactivated by disrupting mitochondrial calcium cycling and could thereby be preserved. However, this possibility also posed a problem: maintenance of the inner membrane potential of the mitochondrion within inactivated sperm. This report describes a series of experiments in which fowl sperm were inactivated by treatment with the calcium chelator tetrasodium 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, and then reactivated by treatment with calcium ions. The effect of tetrasodium 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid on mitochondrial calcium cycling was confirmed by flow cytometry and confocal microscopy. When treated sperm were cooled to 10 degrees C, inactivated sperm could be reactivated throughout a 5-h storage interval. When stored sperm were held for 3 h before reactivation and insemination, fertility was 88% of the control. Storage did not affect hatchability. In summary, short-term storage was realized by manipulating mitochondrial function. We propose that 1) complex V consumes ATP within inactivated sperm and, by doing so, maintains

  17. Effects of cryopreservation on sperm viability, synthesis of reactive oxygen species, and DNA damage of bovine sperm.

    Science.gov (United States)

    Gürler, H; Malama, E; Heppelmann, M; Calisici, O; Leiding, C; Kastelic, J P; Bollwein, H

    2016-07-15

    The objective was to examine if there are relationships between alterations in sperm viability, reactive oxygen species (ROS) synthesis, and DNA integrity induced by cryopreservation of bovine sperm. Four ejaculates were collected from each of six bulls. Each ejaculate was diluted and divided into two aliquots; one was incubated for 24 hours at 37 °C, and the other frozen, thawed, and incubated for 24 hours at 37 °C. Analyses of quality of sperm were performed after 0, 3, 6, 12, and 24 hours of incubation. Progressive motile sperm was determined with computer assisted sperm analysis. Percentages of plasma membrane- and acrosome-intact sperm, sperm with a high mitochondrial membrane potential, sperm showing a high degree of DNA fragmentation (%DFI), and their reactive oxygen species content were assessed with dichlorofluorescein-diacetate, dihydrorhodamine, diaminofluorescein diacetate, and mitochondrial superoxide indicator using flow cytometry. Although all other sperm parameters showed alterations (P  0.05, 0.91 ± 0.23) in nonfrozen sperm. Cryopreservation induced changes of all sperm parameters (P reactive oxygen species. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Assessment of sperm DNA fragmentation in stallion (Equus caballus) and donkey (Equus asinus) using the sperm chromatin dispersion test.

    Science.gov (United States)

    Cortés-Gutiérrez, E I; Crespo, F; Serres-Dalmau, C; Gutiérrez de las Rozas, A L; Dávila-Rodríguez, M I; López-Fernández, C; Gósalvez, J

    2009-10-01

    Sperm DNA fragmentation (sDF) is an important parameter to assessing sperm quality. Information about sperm quality is not available for donkeys, especially in some breeds at risk of extinction. The objectives of this research were to test the four commercial variants of sperm chromatin dispersion test (SCD; sperm Halomax test), originally developed to assess sDF in boars, bulls, rams and stallions, in order to scrutinize their applicability in the study of sDF in a donkey breed at risk of extinction (Zamorano-Leonesa), for which there is no specific test available to analyze sperm at present. Only the SCD test, originally developed for stallions, produced stable and consistent results, and was deemed suitable to assess DNA fragmentation in sperm samples from donkeys. Image analysis was used to compare differences between the SCD methodology applied to stallion and donkey semen samples processed under the same experimental conditions. The extent of SCD in the SCD test was approximately 20% lower in donkey sperm than in stallion sperm. Yet, the ratio of chromatin sperm dispersion achieved in fragmented and unfragmented nuclei did not differ significantly between species. These data suggest that a similar protein depletion treatment can cause differences in protein removal in equivalent cells from different species and that sperm chromatin may be organized differently in stallions and donkeys.

  19. Application of sperm sorting and associated reproductive technology for wildlife management and conservation.

    Science.gov (United States)

    O'Brien, J K; Steinman, K J; Robeck, T R

    2009-01-01

    Efforts toward the conservation and captive breeding of wildlife can be enhanced by sperm sorting and associated reproductive technologies such as sperm cryopreservation and artificial insemination (AI). Sex ratio management is of particular significance to species which naturally exist in female-dominated social groups. A bias of the sex ratio towards females of these species will greatly assist in maintaining socially cohesive groups and minimizing male-male aggression. Another application of this technology potentially exists for endangered species, as the preferential production of females can enable propagation of those species at a faster rate. The particular assisted reproductive technology (ART) used in conjunction with sperm sorting for the production of offspring is largely determined by the quality and quantity of spermatozoa following sorting and preservation processes. Regardless of the ART selected, breeding decisions involving sex-sorted spermatozoa should be made in conjunction with appropriate genetic management. Zoological-based research on reproductive physiology and assisted reproduction, including sperm sorting, is being conducted on numerous terrestrial and marine mammals. The wildlife species for which the technology has undergone the most advance is the bottlenose dolphin. AI using sex-sorted fresh or frozen-thawed spermatozoa has become a valuable tool for the genetic and reproductive management of captive bottlenose dolphins with six pre-sexed calves, all of the predetermined sex born to date.

  20. Motile sperm organelle morphology examination (MSOME: intervariation study of normal sperm and sperm with large nuclear vacuoles

    Directory of Open Access Journals (Sweden)

    Baruffi Ricardo LR

    2010-06-01

    Full Text Available Abstract Background Although the motile sperm organelle morphology examination (MSOME was developed only as a selection criterion, its application as a method for classifying sperm morphology may represent an improvement in evaluation of semen quality, with potential clinical repercussions. The present study aimed to evaluate individual variations in the motile sperm organelle morphology examination (MSOME analysis after a time interval. Methods Two semen samples were obtained from 240 men from an unselected group of couples undergoing infertility investigation and treatment. Mean time interval between the two semen evaluations was 119 +/- 102 days. No clinical or surgical treatment was realized between the two observations. Spermatozoa were analyzed at greater than or equal to 8400× magnification by inverted microscope equipped with DIC/Nomarski differential interference contrast optics. At least 200 motile spermatozoa per semen sample were evaluated and percentages of normal spermatozoa and spermatozoa with large nuclear vacuoles (LNV/one or more vacuoles occupying >50% of the sperm nuclear area were determined. A spermatozoon was classified as morphologically normal when it exhibited a normal nucleus (smooth, symmetric and oval nucleus, width 3.28 +/- 0.20 μm, length 4.75 +/- 0.20 μm/absence of vacuoles occupying >4% of nuclear area as well as acrosome, post-acrosomal lamina, neck and tail, besides not presenting cytoplasm around the head. One examiner, blinded to subject identity, performed the entire study. Results Mean percentages of morphologically normal and LNV spermatozoa were identical in the two MSOME analyses (1.6 +/- 2.2% vs. 1.6 +/- 2.1% P = 0.83 and 25.2 +/- 19.2% vs. 26.1 +/- 19.0% P = 0.31, respectively. Regression analysis between the two samples revealed significant positive correlation for morphologically normal and for LNV spermatozoa (r = 0.57 95% CI:0.47-0.65 P P Conclusions The significant positive correlation and

  1. Secondary Products (Markets, Competition, and Technological Improvements)

    Science.gov (United States)

    Philip A. Araman

    1988-01-01

    Competitiveness, imports, exports, and technological improvements--these are issues facing secondary wood-product manufacturers. The major problems focus on increasing foreign imports and the inability of U.S. industries to repell the imports. How and where should we, as researchers, allocate our efforts to enhance the competitiveness of secondary forest industries in...

  2. The Case for Architectural-Design Competitions

    Science.gov (United States)

    Lewis, Roger K.

    2009-01-01

    A well-publicized design competition is especially beneficial for universities. It allows them to enhance fund raising and stimulate design consciousness among students, the faculty, and even members of the surrounding community. Yet universities rarely conduct competitions, and instead select architects for major projects through a multistep,…

  3. Using a combination of weighting factor method and imperialist competitive algorithm to improve speed and enhance process of reloading pattern optimization of VVER-1000 reactors in transient cycles

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, Yashar, E-mail: yashar.rahmani@gmail.com [Department of Physics, Faculty of Engineering, Islamic Azad University, Sari Branch, Sari (Iran, Islamic Republic of); Shahvari, Yaser [Department of Computer Engineering, Payame Noor University (PNU), P.O. Box 19395-3697, Tehran (Iran, Islamic Republic of); Kia, Faezeh [Golestan Institute of Higher Education, Gorgan 49139-83635 (Iran, Islamic Republic of)

    2017-03-15

    Highlights: • This article was an attempt to optimize reloading pattern of Bushehr VVER-1000 reactor. • A combination of weighting factor method and the imperialist competitive algorithm was used. • The speed of optimization and desirability of the proposed pattern increased considerably. • To evaluate arrangements, a coupling of WIMSD5-B, CITATION-LDI2 and WERL codes was used. • Results reflected the considerable superiority of the proposed method over direct optimization. - Abstract: In this research, an innovative solution is described which can be used with a combination of the new imperialist competitive algorithm and the weighting factor method to improve speed and increase globality of search in reloading pattern optimization of VVER-1000 reactors in transient cycles and even obtain more desirable results than conventional direct method. In this regard, to reduce the scope of the assumed searchable arrangements, first using the weighting factor method and based on values of these coefficients in each of the 16 types of loadable fuel assemblies in the second cycle, the fuel assemblies were classified in more limited groups. In consequence, the types of fuel assemblies were reduced from 16 to 6 and consequently the number of possible arrangements was reduced considerably. Afterwards, in the first phase of optimization the imperialist competitive algorithm was used to propose an optimum reloading pattern with 6 groups. In the second phase, the algorithm was reused for finding desirable placement of the subset assemblies of each group in the optimum arrangement obtained from the previous phase, and thus the retransformation of the optimum arrangement takes place from the virtual 6-group mode to the real mode with 16 fuel types. In this research, the optimization process was conducted in two states. In the first state, it was tried to obtain an arrangement with the maximum effective multiplication factor and the smallest maximum power peaking factor. In

  4. Using a combination of weighting factor method and imperialist competitive algorithm to improve speed and enhance process of reloading pattern optimization of VVER-1000 reactors in transient cycles

    International Nuclear Information System (INIS)

    Rahmani, Yashar; Shahvari, Yaser; Kia, Faezeh

    2017-01-01

    Highlights: • This article was an attempt to optimize reloading pattern of Bushehr VVER-1000 reactor. • A combination of weighting factor method and the imperialist competitive algorithm was used. • The speed of optimization and desirability of the proposed pattern increased considerably. • To evaluate arrangements, a coupling of WIMSD5-B, CITATION-LDI2 and WERL codes was used. • Results reflected the considerable superiority of the proposed method over direct optimization. - Abstract: In this research, an innovative solution is described which can be used with a combination of the new imperialist competitive algorithm and the weighting factor method to improve speed and increase globality of search in reloading pattern optimization of VVER-1000 reactors in transient cycles and even obtain more desirable results than conventional direct method. In this regard, to reduce the scope of the assumed searchable arrangements, first using the weighting factor method and based on values of these coefficients in each of the 16 types of loadable fuel assemblies in the second cycle, the fuel assemblies were classified in more limited groups. In consequence, the types of fuel assemblies were reduced from 16 to 6 and consequently the number of possible arrangements was reduced considerably. Afterwards, in the first phase of optimization the imperialist competitive algorithm was used to propose an optimum reloading pattern with 6 groups. In the second phase, the algorithm was reused for finding desirable placement of the subset assemblies of each group in the optimum arrangement obtained from the previous phase, and thus the retransformation of the optimum arrangement takes place from the virtual 6-group mode to the real mode with 16 fuel types. In this research, the optimization process was conducted in two states. In the first state, it was tried to obtain an arrangement with the maximum effective multiplication factor and the smallest maximum power peaking factor. In

  5. Decline of semen quality among Chinese sperm bank donors within 7 years (2008-2014

    Directory of Open Access Journals (Sweden)

    Li Wang

    2017-01-01

    Full Text Available Semen from 5210 sperm bank donors was analyzed and trends in semen quality were evaluated at Shandong Human Sperm Bank between 2008 and 2014. After 2-7 days of abstinence, semen samples were collected. Measurements of semen volume, sperm concentration, sperm forward motility, and total sperm count were performed. There were significant declining trends in semen volume, sperm concentration, sperm forward motility, and total sperm count. Our results indicate that the quality of semen in this cohort of sperm donors had decreased during the study period.

  6. Human sperm head vacuoles are physiological structures formed during the sperm development and maturation process.

    Science.gov (United States)

    Tanaka, Atsushi; Nagayoshi, Motoi; Tanaka, Izumi; Kusunoki, Hiroshi

    2012-08-01

    To clarify whether human sperm vacuoles affected intracytoplasmic sperm injection (ICSI) success rates. Retrospective study. A private infertility clinic. Spermatozoa and spermatids were obtained from 11 normozoospermic, 10 oligozoospermic or asthenozoospermic, 4 obstructive azoospermic, and 3 nonobstructive azoospermic men. Differential interference contrast observation and intracytoplasmic injection of morphologically selected sperm. Incidence, size, and position of vacuoles of sperm cells were recorded. Ability of fertilization and blastocyst development were compared between cells with and without vacuoles. More than 97.4% of ejaculated, 87.5% of epididymal, 87.5% of testicular spermatozoa, and more than 90.0% of Sc-Sd2 spermatids had vacuoles of various sizes. The incidence of vacuoles on ejaculated cells was significantly higher than that on the other types of cells, but there was no difference between sperm from normozoospermic men and those from the other donors. Removal of plasma membrane and/or acrosome did not affect the incidence of vacuoles. Although more than 60% of spermatozoa had small vacuoles in the acrosomal regions, 52.6% of Sb1-2 spermatids had large vacuoles. After injection of a motile spermatozoon with large and small vacuoles, 60.9% and 85.7% of metaphase II oocytes could be normally fertilized, respectively, and almost half of the zygotes developed to the blastocyst stage. When using sperm without vacuoles, the fertilization rate was 80.0%, but only 25% of them developed to the blastocyst stage. Human sperm head vacuoles did not affect ICSI outcomes. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  7. Sperm vacuoles are linked to capacitation and acrosomal status.

    Science.gov (United States)

    Montjean, Debbie; Belloc, Stephanie; Benkhalifa, Moncef; Dalleac, Alain; Ménézo, Yves

    2012-10-01

    Is the presence of nuclear vacuoles really a negative parameter? As sperm vacuoles are associated with acrosomal and capacitation status, they appear to be a reflection of normal sperm physiology. The selection of sperm under a high magnification has been proposed as a strategy to increase the success rates of ICSI, through a better selection of sperm for injection. The presence of vacuoles on the sperm head is said to be a negative parameter. We incubated processed sperm for 90 min with two strong inducers of acrosome reaction (AR), i.e. hyaluronic acid (HA) and follicular fluid (FF) and studied the evolution of nuclear vacuoles, sperm morphology and chromatin compaction. We tested the effect of incubating sperm samples with HA and FF for 90 min at 37°C on nuclear vacuoles. Both HA and FF strongly induce AR after 90 min, without significantly modifying sperm nuclear condensation and morphology (Bartoov's criteria). We simultaneously observed a highly significant decrease in the presence of vacuoles. This is a descriptive study based on in vitro manipulations. Although intracytoplasmic morphologically selected sperm injection may be of benefit for couples with specific treatment indications, the results of this study make it difficult to justify its large-scale application. Funding was granted by Laboratoire d'Eylau, Unilabs.

  8. Factors affecting sperm quality before and after mating of calopterygid damselflies.

    Directory of Open Access Journals (Sweden)

    Kaori Tsuchiya

    Full Text Available Damselflies (Odonata: Zygoptera have a more complex sperm transfer system than other internally ejaculating insects. Males translocate sperm from the internal reproductive organs to the specific sperm vesicles, a small cavity on the body surface, and then transfer them into the female. To examine how the additional steps of sperm transfer contribute to decreases in sperm quality, we assessed sperm viability (the proportion of live sperm at each stage of mating and after different storage times in male and female reproductive organs in two damselfly species, Mnais pruinosa and Calopteryx cornelia. Viability of stored sperm in females was lower than that of male stores even just after copulation. Male sperm vesicles were not equipped to maintain sperm quality for longer periods than the internal reproductive organs. However, the sperm vesicles were only used for short-term storage; therefore, this process appeared unlikely to reduce sperm viability when transferred to the female. Males remove rival sperm prior to transfer of their own ejaculate using a peculiar-shaped aedeagus, but sperm removal by males is not always complete. Thus, dilution occurs between newly received sperm and aged sperm already stored in the female, causing lower viability of sperm inside the female than that of sperm transferred by males. If females do not remate, sperm viability gradually decreases with the duration of storage. Frequent mating of females may therefore contribute to the maintenance of high sperm quality.

  9. The Semen pH Affects Sperm Motility and Capacitation.

    Science.gov (United States)

    Zhou, Ji; Chen, Li; Li, Jie; Li, Hongjun; Hong, Zhiwei; Xie, Min; Chen, Shengrong; Yao, Bing

    2015-01-01

    As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR), hypo-osmotic swelling (HOS) rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na(+)/K(+)-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM) and laser confocal scanning microscopy (LCSM) analysis, the intracellular Ca2(+ )concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na(+)/K(+)-ATPase activity at acidic pHs result in decreased sperm movement and capacitation, which could be one of the mechanisms of male infertility.

  10. DNA fragmentation and sperm head morphometry in cat epididymal spermatozoa.

    Science.gov (United States)

    Vernocchi, Valentina; Morselli, Maria Giorgia; Lange Consiglio, Anna; Faustini, Massimo; Luvoni, Gaia Cecilia

    2014-10-15

    Sperm DNA fragmentation is an important parameter to assess sperm quality and can be a putative fertility predictor. Because the sperm head consists almost entirely of DNA, subtle differences in sperm head morphometry might be related to DNA status. Several techniques are available to analyze sperm DNA fragmentation, but they are labor-intensive and require expensive instrumentations. Recently, a kit (Sperm-Halomax) based on the sperm chromatin dispersion test and developed for spermatozoa of different species, but not for cat spermatozoa, became commercially available. The first aim of the present study was to verify the suitability of Sperm-Halomax assay, specifically developed for canine semen, for the evaluation of DNA fragmentation of epididymal cat spermatozoa. For this purpose, DNA fragmentation indexes (DFIs) obtained with Sperm-Halomax and terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) were compared. The second aim was to investigate whether a correlation between DNA status, sperm head morphology, and morphometry assessed by computer-assisted semen analysis exists in cat epididymal spermatozoa. No differences were observed in DFIs obtained with Sperm-Halomax and TUNEL. This result indicates that Sperm-Halomax assay provides a reliable evaluation of DNA fragmentation of epididymal feline spermatozoa. The DFI seems to be independent from all the measured variables of sperm head morphology and morphometry. Thus, the evaluation of the DNA status of spermatozoa could effectively contribute to the completion of the standard analysis of fresh or frozen semen used in assisted reproductive technologies. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Sperm vacuoles cannot help to differentiate fertile men from infertile men with normal sperm parameter values.

    Science.gov (United States)

    Gatimel, N; Léandri, R D; Marino, L; Esquerre-Lamare, C; Parinaud, J

    2014-11-01

    Can the assessment of sperm vacuoles at high magnification contribute to the explanation of idiopathic infertility? The characteristics of sperm head vacuoles (number, area, position) are no different between fertile controls and patients with unexplained infertility. Until now, the assessment of sperm head vacuoles has been focused on a therapeutic goal in the intracytoplasmic morphologically selected sperm injection (IMSI) procedure, but it could be pertinent as a new diagnostic tool for the evaluation of male fertility. This diagnostic test study with blind assessment included a population of 50 fertile men and 51 men with idiopathic infertility. They were selected from September 2011 to May 2013. Fertile men were within couples who had a spontaneous pregnancy in the last 2 years. Infertile men were within couples who had unexplained infertility and were consulting in our centre. After analysis of conventional sperm parameters, we investigated the number, position and area of sperm head vacuoles at high magnification (×6000) with interference contrast using an image analysis software. We also carried out a nuclear status analysis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay (TUNEL), sperm chromatin structure assay (SCSA) and aniline blue staining. Concerning the vacuoles data, we did not find any significant difference between the two populations. We found no significant correlation between the vacuolar parameters (mean number of vacuoles, relative vacuole area and percentage of spermatozoa with large vacuoles) and either conventional semen parameters, male age or the data from the aniline blue staining, SCSA assay and TUNEL assay. Despite the fact all of the vacuole parameters values were identical in fertile and infertile men, we cannot totally exclude that a very small cause of unexplained infertilities could be related to an excess of sperm vacuoles. In line with its widely debated use as a therapeutic tool, sperm vacuole

  12. Effects of Synthetic Serum Supplementation in Sperm Preparation Media on Sperm Capacitation and Function Test Results

    Directory of Open Access Journals (Sweden)

    Ying-Fu Shih

    2016-01-01

    Full Text Available Albumin supplementation of culture media induces sperm capacitation in assisted reproduction technique cycles. Synthetic serum supplementation is clinically used to replace albumin for preventing transmission of infectious agents. However, the effects of synthetic serum supplementation on sperm capacitation have rarely been investigated. Spermatozoa from 30 men with normal basic semen analysis results were collected, divided into five aliquots, and cultured in capacitating conditions in four combinations of two synthetic serum supplements, serum substitute supplement (SSS and serum protein substitute (SPS, and two fertilization media, Quinns Advantage™ Fertilization (QF and human tubular fluid (HTF media. Reactive oxygen species (ROS levels in spermatozoa were measured through chemiluminescence. Furthermore, acrosome reaction and western blotting for tyrosine phosphorylation were used to evaluate sperm capacitation. HTF+SSS had significantly higher ROS levels than QF+SPS did (11,725 ± 1,172 versus 6,278 ± 864 relative light units. In addition, the spermatozoa cultured in QF+SPS had lower motility, acrosome reaction rates, and tyrosine phosphorylation levels compared with those cultured in HTF+SSS. In conclusion, the effects of synthetic serum supplementation on sperm capacitation varied according to the combination of media. These differences may lead to variations in spermatozoon ROS levels, thus affecting sperm function test results.

  13. Sperm Impairment by Sperm Agglutinating Factor Isolated from Escherichia coli: Receptor Specific Interactions

    Directory of Open Access Journals (Sweden)

    Kiranjeet Kaur

    2013-01-01

    Full Text Available In an earlier work done in our laboratory, we have been able to isolate a sperm agglutinating strain of Escherichia coli from the semen sample of a male attending infertility clinic. Further, factor responsible for sperm agglutination (SAF was isolated and purified, and, using SAF as a tool, corresponding SAF binding receptor from human spermatozoa has been purified. Characterization of SAF and SAF binding receptor using MALDI-TOF showed homology to glutamate decarboxylase and MHC class I molecule, respectively. Coincubation of SAF with spermatozoa not only resulted in spermagglutination but could also compromise other sperm parameters, namely, Mg2+ dependent ATPase activity and apoptosis. Intravaginal administration of SAF could lead to infertility in Balb/c mice. SAF induced impairment of sperm parameters, and infertility was observed to be due to interaction of SAF with sperm surface receptor component as, when purified receptor was introduced, receptor completely inhibited all the detrimental effects induced by SAF. From these results, it could be concluded that interaction of SAF with spermatozoa is receptor mediated.

  14. Evaluation of Lasting Effects of Heat Stress on Sperm Profile and Oxidative Status of Ram Semen and Epididymal Sperm

    Directory of Open Access Journals (Sweden)

    Thais Rose dos Santos Hamilton

    2016-01-01

    Full Text Available Higher temperatures lead to an increase of testicular metabolism that results in spermatic damage. Oxidative stress is the main factor responsible for testicular damage caused by heat stress. The aim of this study was to evaluate lasting effects of heat stress on ejaculated sperm and immediate or long-term effects of heat stress on epididymal sperm. We observed decrease in motility and mass motility of ejaculated sperm, as well as an increase in the percentages of sperm showing major and minor defects, damaged plasma and acrosome membranes, and a decrease in the percentage of sperm with high mitochondrial membrane potential in the treated group until one spermatic cycle. An increased enzymatic activity of glutathione peroxidase and an increase of stressed cells were observed in ejaculated sperm of the treated group. A decrease in the percentage of epididymal sperm with high mitochondrial membrane potential was observed in the treated group. However, when comparing immediate and long-term effects, we observed an increase in the percentage of sperm with low mitochondrial membrane potential. In conclusion, testicular heat stress induced oxidative stress that led to rescuable alterations after one spermatic cycle in ejaculated sperm and also after 30 days in epididymal sperm.

  15. Matrine Inhibits Mouse Sperm Function by Reducing Sperm [Ca2+]i and Phospho-ERK1/2

    Directory of Open Access Journals (Sweden)

    Tao Luo

    2015-01-01

    Full Text Available Background: Matrine is a bioactive alkaloid that has a variety of pharmacological effects and is widely used in Chinese medicine. However, its effects on male reproduction are not well known. In this study, we aimed to investigate the in vitro toxicity of matrine on mature mouse sperm. Methods: Mouse cauda epididymal sperm were exposed to matrine (10-200 µM in vitro. The viability, motility, capacitation, acrosome reaction and fertilization ability of the mouse sperm were examined. Furthermore, the intracellular calcium concentration ([Ca2+]i, calcium (Catsper and potassium (Ksper currents, and phosphorylation of extracellular signal regulated kinases 1/2 (p-ERK1/2 of the sperm were analyzed. Results: After exposure to 100 µM or more of matrine, mouse cauda epididymal sperm exhibited a significant reduction in total motility, progressive motility, linear velocity and acrosome reaction rate induced by Ca2+ ionophore A23187. As a result, the fertilization ability of mouse sperm was remarkably decreased by matrine. Our data further demonstrated that matrine significantly reduced sperm [Ca2+]i and [Ca2+]i-related p-ERK1/2; however, both the CatSper and KSper currents, which are thought to interactively regulate Ca2+ influx in sperm, were not affected by matrine. Conclusion: Our findings indicate that matrine inhibits mouse sperm function by reducing sperm [Ca2+]i and suppressing the phosphorylation of ERK1/2.

  16. Purification and characterization of a sperm motility inhibiting factor from caprine epididymal plasma.

    Directory of Open Access Journals (Sweden)

    Sujoy Das

    Full Text Available Several studies have been reported on the occurrence of sperm motility inhibiting factors in the male reproductive fluids of different mammalian species, but these proteins have not been adequately purified and characterized. A novel sperm motility inhibiting factor (MIF-II has been purified from caprine epididymal plasma (EP by Hydroxylapatite gel adsorption chromatography, DEAE-Cellulose ion-exchange chromatography and chromatofocusing. The MIF-II has been purified to apparent homogeneity and the molecular weight estimated by Sephacryl S-300 gel filtration is 160 kDa. MIF-II is a dimeric protein, made up of two subunits each having a molecular mass of 80 kDa as shown by SDS-PAGE. The isoelectric point of MIF-II is 5.1 as determined by chromatofocusing and isoelectric focusing. It is a heat labile protein and maximal active at the pH 6.9 to 7.5. The sperm motility inhibiting protein factor at 2 microg/ml (12.5 nM level showed maximal motility-inhibiting activity. The observation that the epididymal plasma factor lowered the intracellular cAMP level of spermatozoa in a concentration-dependent manner suggests that it may block the motility of caprine cauda spermatozoa by interfering the cAMP dependent motility function. The results revealed that the purified protein factor has the potential of sperm motility inhibition and may serve as a vaginal contraceptive. The antibody raised against the MIF-II has the potential for enhancement of forward motility of cauda-spermatozoa. This antibody may thus be useful for solving some of the problems of male infertility due to low sperm motility.

  17. Presence and function of dopamine transporter (DAT in stallion sperm: dopamine modulates sperm motility and acrosomal integrity.

    Directory of Open Access Journals (Sweden)

    Javier A Urra

    Full Text Available Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is as yet unknown. We have previously shown that dopamine type 2 receptor is functional in boar sperm, suggesting that dopamine acts as a physiological modulator of sperm viability, capacitation and motility. In the present study, using immunodetection methods, we revealed the presence of several proteins important for the dopamine uptake and signalling in mammalian sperm, specifically monoamine transporters as dopamine (DAT, serotonin (SERT and norepinephrine (NET transporters in equine sperm. We also demonstrated for the first time in equine sperm a functional dopamine transporter using 4-[4-(Dimethylaminostyryl]-N-methylpyridinium iodide (ASP(+, as substrate. In addition, we also showed that dopamine (1 mM treatment in vitro, does not affect sperm viability but decreases total and progressive sperm motility. This effect is reversed by blocking the dopamine transporter with the selective inhibitor vanoxerine (GBR12909 and non-selective inhibitors of dopamine reuptake such as nomifensine and bupropion. The effect of dopamine in sperm physiology was evaluated and we demonstrated that acrosome integrity and thyrosine phosphorylation in equine sperm is significantly reduced at high concentrations of this catecholamine. In summary, our results revealed the presence of monoamine transporter DAT, NET and SERT in equine sperm, and that the dopamine uptake by DAT can regulate sperm function, specifically acrosomal integrity and sperm motility.

  18. Proteins associated with critical sperm functions and sperm head shape are differentially expressed in morphologically abnormal bovine sperm induced by scrotal insulation

    NARCIS (Netherlands)

    Saadi, H.A.S.; Riemsdijk, van E.L.C.; Dance, A.L.; Rajamanickam, G.D.; Kastelic, J.P.; Thundathil, J.C.

    2013-01-01

    The objective was to investigate expression patterns of proteins in pyriform sperm, a common morphological abnormality in bull sperm. Ejaculates were collected from sexually mature Holstein bulls (n = 3) twice weekly for 10 weeks (pre-thermal insult samples). Testicular temperature was elevated in

  19. Method-related estimates of sperm vitality.

    Science.gov (United States)

    Cooper, Trevor G; Hellenkemper, Barbara

    2009-01-01

    Comparison of methods that estimate viability of human spermatozoa by monitoring head membrane permeability revealed that wet preparations (whether using positive or negative phase-contrast microscopy) generated significantly higher percentages of nonviable cells than did air-dried eosin-nigrosin smears. Only with the latter method did the sum of motile (presumed live) and stained (presumed dead) preparations never exceed 100%, making this the method of choice for sperm viability estimates.

  20. Methods for cryopreservation of guinea fowl sperm.

    Directory of Open Access Journals (Sweden)

    Éva Váradi

    Full Text Available Conservation of indigenous poultry species is an important part of the new Hungarian agricultural strategy. Semen cryopreservation is the most practical method for the long term storage of poultry genetic material. The objective was to compare four protocols for cryopreservation of guinea fowl sperm (slow and fast programmable, freezing in nitrogen vapor, and pellet and three cryoprotectants (10% ethylene glycol, 6% dimethyl-formamide and 6% dimethyl-acetamide. The efficiency of the methods was examined by in vitro tests (subjective motility scoring, sperm concentration, morphological and live/dead sperm analysis with eosin-aniline staining. Thereafter, the two most promising methods were tested by artificial insemination of frozen-thawed semen (3 times a week for 3 weeks using 300 million spermatozoa/hen, followed by candling of incubated eggs, assessment of fertilization, embryonic death, and hatching rate. The survival rate of live, intact spermatozoa was greatest (p≤0.05 in pellet method and the slow programmable protocol (with 10% ethylene glycol (28.6 and 23.5%. The two best protocols (based on in vitro assessment of post-thaw semen quality were subsequently tested in vivo with artificial insemination. The pellet method yielded a 64% fertility rate compared to slow protocol with only 30% fertility. Regardless, both freezing protocols significantly increased embryonic deaths compared to the control group (16,7; 9,1 and 8,3%, respectively. During the 3-week in vivo trial, fertility increased and early embryonic death decreased over time. According to the results the guinea fowl sperm could tolerate the fast freezing in pellet better than the slower freezing rates and resulted acceptable fertility rate.

  1. Formation and development of sperms in angiosperms

    Directory of Open Access Journals (Sweden)

    S. Tatintseva

    2014-01-01

    Full Text Available Spermiogelnesis has been studied in a large number of Angiosperm species characterizing different levels of phylogenetic system. The formation and development of male gamets can be described as formation of sperm cells that undergo ontogenesis which stimulates changes up to full maturity of the pollen grain. The process of ontogenesis is aimed at creating a suitable delivery system by the pollen tube to a female gamete.

  2. Sperm navigation along helical paths in 3D chemoattractant landscapes

    Science.gov (United States)

    Jikeli, Jan F.; Alvarez, Luis; Friedrich, Benjamin M.; Wilson, Laurence G.; Pascal, René; Colin, Remy; Pichlo, Magdalena; Rennhack, Andreas; Brenker, Christoph; Kaupp, U. Benjamin

    2015-08-01

    Sperm require a sense of direction to locate the egg for fertilization. They follow gradients of chemical and physical cues provided by the egg or the oviduct. However, the principles underlying three-dimensional (3D) navigation in chemical landscapes are unknown. Here using holographic microscopy and optochemical techniques, we track sea urchin sperm navigating in 3D chemoattractant gradients. Sperm sense gradients on two timescales, which produces two different steering responses. A periodic component, resulting from the helical swimming, gradually aligns the helix towards the gradient. When incremental path corrections fail and sperm get off course, a sharp turning manoeuvre puts sperm back on track. Turning results from an `off' Ca2+ response signifying a chemoattractant stimulation decrease and, thereby, a drop in cyclic GMP concentration and membrane voltage. These findings highlight the computational sophistication by which sperm sample gradients for deterministic klinotaxis. We provide a conceptual and technical framework for studying microswimmers in 3D chemical landscapes.

  3. Aspermy, sperm quality and radiation in Chernobyl birds.

    Science.gov (United States)

    Møller, Anders Pape; Bonisoli-Alquati, Andrea; Mousseau, Timothy A; Rudolfsen, Geir

    2014-01-01

    Following the Chernobyl nuclear power plant accident, large amounts of radionuclides were emitted and spread in the environment. Animals living in such contaminated areas are predicted to suffer fitness costs including reductions in the quality and quantity of gametes. We studied whether aspermy and sperm quality were affected by radioactive contamination by examining ejaculates from wild caught birds breeding in areas varying in background radiation level by more than three orders of magnitude around Chernobyl, Ukraine. The frequency of males with aspermy increased logarithmically with radiation level. While 18.4% of males from contaminated areas had no sperm that was only the case for 3.0% of males from uncontaminated control areas. Furthermore, there were negative relationships between sperm quality as reflected by reduced sperm velocity and motility, respectively, and radiation. Our results suggest that radioactive contamination around Chernobyl affects sperm production and quality. We are the first to report an interspecific difference in sperm quality in relation to radioactive contamination.

  4. Progress and challenges of fish sperm vitrification: A mini review.

    Science.gov (United States)

    Xin, Miaomiao; Siddique, Mohammad Abdul Momin; Dzyuba, Borys; Cuevas-Uribe, Rafael; Shaliutina-Kolešová, Anna; Linhart, Otomar

    2017-08-01

    To survive low temperature is required for a long-term storage (cryopreservation), cells should be vitrified to a state in which intracellular water is solidified without ice crystal formation. Two different approaches are described for fish sperm cryopreservation: 1) sperm conventional cryopreservation, in which extracellular water is partially crystallized and 2) sperm vitrification, in which both intra- and extra-cellular liquids are vitrified. Sperm vitrification has been applied to some fish species with limited success. Traditional vitrification requires rapid cooling/warming rates, small sample carriers, and using high permeable cryoprotectant concentrations. The latter cause cytotoxic effects which must be well managed and will require continuous effort to match an appropriate cryoprotectant with suitable apparatus and warming methods. Novel cryoprotectant-free sperm vitrification approach has been applied to several fishes. This review summarizes development of basic procedures and discusses advantages and disadvantages of vitrification when applied it to fish sperm. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Association between chronic pain and the sperm motion characteristics

    DEFF Research Database (Denmark)

    Dardmeh, Fereshteh; Alipour, Hiva; Nielsen, Hans Ingolf

    2015-01-01

    Sex hormones play an important role in pain in many chronic pain conditions. Relationship between chronic pain and sperm quality has not been investigated thoroughly and may provide an insight to better understanding, management and treatment of cases where chronic pain and male sub-fertility co......-exist. Neat (fresh semen) and processed sperm from 15 males with orthopedic chronic pain (CP) were assessed and compared with 15 healthy age matched controls. Sperm analysis was performed using the SCA computer-aided sperm analyzer. There was no significant difference in any parameters of the neat semen...... significantly higher in the processed sample of the CP group. This study demonstrated that chronic pain does not affect the sperm morphology, total concentration and motility based on conventional analysis but has significant influence at the level of sperm motion kinetics which could prove to be clinically...

  6. Accountings of Selecting Sperm on the (ethical) border

    DEFF Research Database (Denmark)

    Willum Adrian, Stine

    During the past years, Denmark has become a destination for fertility travellers, in need for donated sperm. Today, treatment is possible no matter of marital status or sexuality. Furthermore, users of sperm donation can choose between anonymous and non-anonymous sperm, with either basic...... will analyze how women and their partners crossing the Danish border accounts for their donor choice, and their practices of choosing. I will be exploring the question: How are women and their partners accounting for choosing a sperm donor, crossing the (ethical) border to Denmark? The use of the term......-sited ethnographic fieldwork at a Danish private fertility clinic, and a Danish sperm bank. The presentation will mainly draw on interviews with fertility travellers going through treatment with donor sperm in Denmark....

  7. Some Reflections on Intracytoplasmic Morphologically Selected Sperm Injection

    Directory of Open Access Journals (Sweden)

    Thomas Ebner

    2014-07-01

    Full Text Available Although intracytoplasmic sperm injection (ICSI allows proper fertilization in most cases of male sub fertility, it is one of the most unphysiological techniques in assisted reproductive technologies (ART. Thus, over the last decade, researchers have tried to improve sperm observation with higher-resolution microscopy techniques such as the intracytoplasmic morphologically selected sperm injection (IMSI technique. In order to identify literatures for this review, the PubMed database was searched from 2000 onwards using the terms IMSI, motile sperm organelle morphology examination (MSOME and sperm vacuole. Approximately 10 years after the introduction of the MSOME and IMSI procedures, several questions related to the prevalence, origin, location, and clinical consequences of sperm vacuoles have not yet been clarified. It seems that IMSI as a routine application is not state of the art and the only confirmed indications for IMSI are recurrent implantation failure following ICSI and severe male factor.

  8. Mixing, entropy and competition

    International Nuclear Information System (INIS)

    Klimenko, A Y

    2012-01-01

    Non-traditional thermodynamics, applied to random behaviour associated with turbulence, mixing and competition, is reviewed and analysed. Competitive mixing represents a general framework for the study of generic properties of competitive systems and can be used to model a wide class of non-equilibrium phenomena ranging from turbulent premixed flames and invasion waves to complex competitive systems. We demonstrate consistency of the general principles of competition with thermodynamic description, review and analyse the related entropy concepts and introduce the corresponding competitive H-theorem. A competitive system can be characterized by a thermodynamic quantity—competitive potential—which determines the likely direction of evolution of the system. Contested resources tend to move between systems from lower to higher values of the competitive potential. There is, however, an important difference between conventional thermodynamics and competitive thermodynamics. While conventional thermodynamics is constrained by its zeroth law and is fundamentally transitive, the transitivity of competitive thermodynamics depends on the transitivity of the competition rules. Intransitivities are common in the real world and are responsible for complex behaviour in competitive systems. This work follows ideas and methods that have originated from the analysis of turbulent combustion, but reviews a much broader scope of issues linked to mixing and competition, including thermodynamic characterization of complex competitive systems with self-organization. The approach presented here is interdisciplinary and is addressed to the general educated readers, whereas the mathematical details can be found in the appendices. (comment)

  9. COMPETITION ADVOCACY: CHALLENGE FOR COMPETITION POLICY

    Directory of Open Access Journals (Sweden)

    Anatolie CARAGANCIU

    2014-11-01

    Full Text Available A large variety of different countries conditions requires a modernization of criteria, norms and standards of competition regulation and methods of enforcement. Competition advocacy is a type of complementary activity exercised by antimonopoly authorities additional to enforcement measures, through active cooperation with market, government and civil society actors and increasing the understanding of the benefits of competition. Relevance of article is determined by summarizing the theoretical studies and the present practice of advocacy in the USA and the EU. Originality and practical applications of research are based on empirical studies completed by Moldovan Competition Board.

  10. Iron supplementation prevents a decline in iron stores and enhances strength performance in elite female volleyball players during the competitive season.

    Science.gov (United States)

    Mielgo-Ayuso, Juan; Zourdos, Michael C; Calleja-González, Julio; Urdampilleta, Aritz; Ostojic, Sergej

    2015-06-01

    The primary aim of this study was to examine the effects of 11 weeks of iron supplementation on hematological and strength markers in elite female volleyball players. Twenty-two volleyball players (aged 27.0 ± 5.6 years) from 2 Spanish First National League teams participated and were counterbalanced into 1 of 2 groups based upon iron status: (i) control group (CG, n = 11); or (ii) iron treatment group (ITG, n = 11), which received 325 mg/day of ferrous sulphate daily. Subjects performed their team's regimen of training or match play every day. Both groups were tested for hematological and strength levels at 2 points: (i) baseline (T0, before preseason) and (ii) 11 weeks later (T11, post-testing). Hematological parameters were serum iron (sFe), serum ferritin (FER), transferrin saturation index (TSI), and hemoglobin (Hb); strength assessments were bench press, military press, half-squat, power clean, clean and jerk, and pull-over. CG experienced a significant decrease (p 0.05). Consequently, in ITG all hematological parameters were significantly greater (p volleyball players during the competitive season.

  11. Competition on European energy markets

    International Nuclear Information System (INIS)

    Lijesen, M.; Speck, S; Mulder, M.

    2003-01-01

    The launch of the Directives on Electricity and Gas in the late 1990s was the starting point for creating common and competitive energy markets in the European Union. The main goal of this process was to increase efficiency of allocation of resources and, hence,enhance consumer welfare. More specifically, increasing competition within the energy markets should lead to a reduction of energy prices and to a convergence of prices among EU member states. Within a year from now, end-users in the Netherlands will be free to choose their own supplier, thus finalising the deregulation of Dutch energy markets. What lessons may be learned from the experience thus far? What are the results of the liberalisation process up to now? How have prices developed,and can these developments be explained? How afraid should we be for the lights to go out in a competitive electricity market?

  12. Puma (Puma concolor) epididymal sperm morphometry.

    Science.gov (United States)

    Cucho, Hernán; Alarcón, Virgilio; Ordóñez, César; Ampuero, Enrique; Meza, Aydee; Soler, Carles

    2016-01-01

    The Andean puma (Puma concolor) has not been widely studied, particularly in reference to its semen characteristics. The aim of the present study was to define the morphometry of puma sperm heads and classify their subpopulations by cluster analysis. Samples were recovered postmortem from two epididymides from one animal and prepared for morphological observation after staining with the Hemacolor kit. Morphometric data were obtained from 581 spermatozoa using a CASA-Morph system, rendering 13 morphometric parameters. The principal component (PC) analysis was performed followed by cluster analysis for the establishment of subpopulations. Two PC components were obtained, the first related to size and the second to shape. Three subpopulations were observed, corresponding to elongated and intermediate-size sperm heads and acrosomes, to large heads with large acrosomes, and to small heads with short acrosomes. In conclusion, puma spermatozoa showed no uniform sperm morphology but three clear subpopulations. These results should be used for future work in the establishment of an adequate germplasm bank of this species.

  13. Studies on mating competitiveness of sterile oriental fruit fly, Bactrocera dorsalis (Hendel)

    International Nuclear Information System (INIS)

    Limohpasmanee, W.; Segsarnviriya, S.

    1998-01-01

    An essential prerequisite for insect control by the sterile insect technique releasing method is mass rearing and sterilizing that do not have adverse effects on longevity and mating behavior of the released males. But many laboratory studies have shown that males irradiated at the completely sterility dose often could not compete with untreated males in mating. This paper studies the effects of gamma radiation at the sterile dose on mating, sexual and sperm competitiveness of the oriental fruit fly, Bactrocera dorsalis (Hendel) under the laboratory condition. It is found that irradiation at the completely sterility dose (90 Gy) had reduced the mating and sperm competition ability of the males. Though the sexual competition was not

  14. Driving Competitiveness Through Servitization

    DEFF Research Database (Denmark)

    Avlonitis, Viktor; Frandsen, Thomas; Hsuan, Juliana

    Servitization, or adding services to the manufactured product, has become a strategy for increasing financial margins, getting closer to the customer and prolonging product lives. This is especially applicable to Western hemisphere companies in their efforts to compete with companies from low cost...... countries and emerging economies. It is our hope that this booklet can assist managers to analyze and plan a servitization strategy. The text is brief and comprehensive to supplement a workshop, but can also be used separately as a quick guide on steps to follow for a manager when considering servitization...... for the company. This booklet is produced to serve as a documentation of a research project together with industry on how servitization can be a strategy to enhance the competitiveness of manufacturing firms....

  15. Treating boar sperm with cholesterol-loaded cyclodextrins or cyclodextrins prior to cryopreservation: effects on post-thaw in vitro sperm quality of sperm cryopreserved in different freezing extenders.

    OpenAIRE

    BLANCH TORRES, EVA

    2016-01-01

    [EN] Cryopreserved boar sperm is not used extensively for artificial insemination due to poor fertility rates of the sperm after freezing and thawing. The sperm membrane is damaged when cooled from body temperature to 5 ºC (cold shock), as well as during the freeze-thaw process. Increasing the cholesterol content of boar sperm membranes could increase their post-thaw survival, similarly to other species that are cold shock sensitive. Cholesterol can be easily added to sperm membranes using ch...

  16. A dictionary learning approach for human sperm heads classification.

    Science.gov (United States)

    Shaker, Fariba; Monadjemi, S Amirhassan; Alirezaie, Javad; Naghsh-Nilchi, Ahmad Reza

    2017-12-01

    To diagnose infertility in men, semen analysis is conducted in which sperm morphology is one of the factors that are evaluated. Since manual assessment of sperm morphology is time-consuming and subjective, automatic classification methods are being developed. Automatic classification of sperm heads is a complicated task due to the intra-class differences and inter-class similarities of class objects. In this research, a Dictionary Learning (DL) technique is utilized to construct a dictionary of sperm head shapes. This dictionary is used to classify the sperm heads into four different classes. Square patches are extracted from the sperm head images. Columnized patches from each class of sperm are used to learn class-specific dictionaries. The patches from a test image are reconstructed using each class-specific dictionary and the overall reconstruction error for each class is used to select the best matching class. Average accuracy, precision, recall, and F-score are used to evaluate the classification method. The method is evaluated using two publicly available datasets of human sperm head shapes. The proposed DL based method achieved an average accuracy of 92.2% on the HuSHeM dataset, and an average recall of 62% on the SCIAN-MorphoSpermGS dataset. The results show a significant improvement compared to a previously published shape-feature-based method. We have achieved high-performance results. In addition, our proposed approach offers a more balanced classifier in which all four classes are recognized with high precision and recall. In this paper, we use a Dictionary Learning approach in classifying human sperm heads. It is shown that the Dictionary Learning method is far more effective in classifying human sperm heads than classifiers using shape-based features. Also, a dataset of human sperm head shapes is introduced to facilitate future research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Parallel Evolution of Sperm Hyper-Activation Ca2+ Channels.

    Science.gov (United States)

    Cooper, Jacob C; Phadnis, Nitin

    2017-07-01

    Sperm hyper-activation is a dramatic change in sperm behavior where mature sperm burst into a final sprint in the race to the egg. The mechanism of sperm hyper-activation in many metazoans, including humans, consists of a jolt of Ca2+ into the sperm flagellum via CatSper ion channels. Surprisingly, all nine CatSper genes have been independently lost in several animal lineages. In Drosophila, sperm hyper-activation is performed through the cooption of the polycystic kidney disease 2 (pkd2) Ca2+ channel. The parallels between CatSpers in primates and pkd2 in Drosophila provide a unique opportunity to examine the molecular evolution of the sperm hyper-activation machinery in two independent, nonhomologous calcium channels separated by > 500 million years of divergence. Here, we use a comprehensive phylogenomic approach to investigate the selective pressures on these sperm hyper-activation channels. First, we find that the entire CatSper complex evolves rapidly under recurrent positive selection in primates. Second, we find that pkd2 has parallel patterns of adaptive evolution in Drosophila. Third, we show that this adaptive evolution of pkd2 is driven by its role in sperm hyper-activation. These patterns of selection suggest that the evolution of the sperm<