Journal articles: 'Male gametes'

1

Buyser, J. De, B. Bachelier, and Y. Henry. "Gametic selection during wheat anther culture." Genome 32, no. 1 (February 1, 1989): 54–56. http://dx.doi.org/10.1139/g89-410.

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Gametic selection was investigated in a monosomic 1D line of wheat. Comparison of chromosome numbers in progenies from cross- or self-pollination and anther culture indicated the frequency of the different types of gametes acting in zygote formation. The progenies obtained from reciprocal crosses (monosomic × euploid) were different in terms of frequencies of monosomic plants. All the pollen grains do not have an equal probability of fertilization since a strong gametic selection for euhaploid male gametes was observed when the monosomic line was used as male parent; only 13% of the nullisomic survived to embryogenesis and seed germination. Regenerants from anther culture also demonstrated that the percentage of nullihaploids was reduced, indicating a strong selection for euhaploid gametes. A comparison between the frequency of male nullihaploid gametes in the cross disomic × monosomic and in the anther culture revealed that the two processes generate the same gamete transmission. The in vitro cultures do not induce more selection pressure than the embryogenic development even if they are together biased samples of the male gametic population.

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NEAL, A. T. "Male gametocyte fecundity and sex ratio of a malaria parasite, Plasmodium mexicanum." Parasitology 138, no. 10 (July 15, 2011): 1203–10. http://dx.doi.org/10.1017/s0031182011000941.

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SUMMARYEvolutionary theory predicts that the sex ratio of Plasmodium gametocytes will be determined by the number of gametes produced per male gametocyte (male fecundity), parasite clonal diversity and any factor that reduces male gametes' ability to find and combine with female gametes. Despite the importance of male gametocyte fecundity for sex ratio theory as applied to malaria parasites, few data are available on gamete production by male gametocytes. In this study, exflagellating gametes, a measure of male fecundity, were counted for 866 gametocytes from 26 natural infections of the lizard malaria parasite, Plasmodium mexicanum. The maximum male fecundity observed was 8, but most gametocytes produced 2–3 gametes, a value consistent with the typical sex ratio observed for P. mexicanum. Male gametocytes in infections with higher gametocytaemia had lower fecundity. Male fecundity was not correlated with gametocyte size, but differed among infections, suggesting genetic variation for fecundity. Fecundity and sex ratio were correlated (more female gametocytes with higher fecundity) as predicted by theory. Results agree with evolutionary theory, but also suggest a possible tradeoff between production time and fecundity, which could explain the low fecundity of this species, the variation among infections, and the correlation with gametocytaemia.

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Ogura, A., and R. Yanagimachi. "Spermatids as male gametes." Reproduction, Fertility and Development 7, no. 2 (1995): 155. http://dx.doi.org/10.1071/rd9950155.

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Intracytoplasmic sperm injection (ICSI) is becoming increasingly popular in human infertility clinics as an efficient method for the treatment of male infertility. It is proposed that spermatids can be used as substitutes for spermatozoa if men are unable to produce sperm in their testes. At least in the hamster and mouse, the nuclei of round spermatids were capable of participating in syngamy when incorporated into homologous mature oocytes either by microsurgical ICSI or electrofusion. Normal mouse offspring were born after after electrofusion of oocytes with round spermatids. When culture in vitro of spermatogonia and spermatocytes is perfected, then spermatids, transforming spermatids and spermatozoa will all be able to be used as male gametes.

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Lehtonen, Jussi, and Heikki Helanterä. "Superorganismal anisogamy: queen–male dimorphism in eusocial insects." Proceedings of the Royal Society B: Biological Sciences 287, no. 1928 (June 10, 2020): 20200635. http://dx.doi.org/10.1098/rspb.2020.0635.

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Colonies of insects such as ants and honeybees are commonly viewed as ‘superorganisms’, with division of labour between reproductive ‘germline-like’ queens and males and ‘somatic’ workers. On this view, properties of the superorganismal colony are comparable with those of solitary organisms to such an extent that the colony itself can be viewed as a unit analogous to an organism. Thus, the concept of a superorganism can be useful as a guide to thinking about life history and allocation traits of colonies as a whole. A pattern that seems to reoccur in insects with superorganismal societies is size dimorphism between queens and males, where queens tend to be larger than males. It has been proposed that this is analogous to the phenomenon of anisogamy at the level of gametes in organisms with separate sexes; more specifically, it is suggested that this caste dimorphism may have evolved via similar selection pressures as gamete dimorphism arises in the ‘gamete competition’ theory for the evolution of anisogamy. In this analogy, queens are analogous to female gametes, males are analogous to male gametes, and colony survival is analogous to zygote survival in gamete competition theory. Here, we explore if this question can be taken beyond an analogy, and whether a mathematical model at the superorganism level, analogous to gamete competition at the organism level, may explain the caste dimorphism seen in superorganismal insects. We find that the central theoretical idea holds, but that there are also significant differences between the way this generalized ‘propagule competition’ theory operates at the levels of solitary organisms and superorganisms. In particular, we find that the theory can explain superorganismal caste dimorphism, but compared with anisogamy evolution, a central coevolutionary link is broken, making the requirements for the theory to work less stringent than those found for the evolution of anisogamy.

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Schoen, D. J., and S. C. Stewart. "Variation in Male Fertilities and Pairwise Mating Probabilities in Picea glauca." Genetics 116, no. 1 (May 1, 1987): 141–52. http://dx.doi.org/10.1093/genetics/116.1.141.

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ABSTRACT Frequencies of multilocus male gametes in seeds collected from clones in several blocks of a white spruce seed orchard were analyzed as part of a 2-yr study of mating system variation in this species. Observed frequencies of male gamete types departed significantly from those expected assuming equal male fertilities among clones. Male gamete frequencies in seed crops were significantly heterogeneous among clones within blocks, and among blocks within clones. Clonal male fertilities were estimated from male gamete frequency data. These estimates were highly skewed, with a small proportion of the clones contributing male gametes to the majority of the seed. The estimates were significantly heterogeneous among clones within blocks, and among blocks within clones. Between-year variation in clonal male fertilities was also pronounced, with male fertilities of some clones changing by as much as three orders of magnitude. Clonal male fertility was significantly correlated with clonal male cone production in both years. These results are important with regard to assumptions made for the estimation of general combining ability, average genetic correlation among progeny from single parents, and expected response to selection in open-pollinated plant populations.

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CEBRAT, S., and D. STAUFFER. "GAMETE RECOGNITION AND COMPLEMENTARY HAPLOTYPES IN SEXUAL PENNA AGEING MODEL." International Journal of Modern Physics C 19, no. 02 (February 2008): 259–65. http://dx.doi.org/10.1142/s0129183108012066.

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In simulations of sexual reproduction with diploid individuals, we introduce female haploid gametes that recognize one specific allele of the genomes as a marker of the male haploid gametes. They fuse to zygotes preferably with male gametes having a different marker than their own. This gamete recognition enhances the advantage of complementary bit-strings in the simulated diploid individuals, at low recombination rates. Thus with rare recombinations the bit-strings evolve to be complementary; with recombination rates above approximately 0.1 they instead evolve under Darwinian purification selection, with few bits mutated.

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7

Griswold, M. D. "Making male gametes in culture." Proceedings of the National Academy of Sciences 109, no. 42 (October 9, 2012): 16762–63. http://dx.doi.org/10.1073/pnas.1215088109.

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8

Lansac, J. "Male gametes: Production and quality." European Journal of Obstetrics & Gynecology and Reproductive Biology 70, no. 2 (December 1996): 221. http://dx.doi.org/10.1016/s0301-2115(95)02577-4.

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9

Charlesworth, Brian. "The origin of male gametes." Current Biology 17, no. 5 (March 2007): R163. http://dx.doi.org/10.1016/j.cub.2007.01.056.

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10

García-Rodríguez, Anaís, Jaime Gosálvez, Ashok Agarwal, Rosa Roy, and Stephen Johnston. "DNA Damage and Repair in Human Reproductive Cells." International Journal of Molecular Sciences 20, no. 1 (December 21, 2018): 31. http://dx.doi.org/10.3390/ijms20010031.

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The fundamental underlying paradigm of sexual reproduction is the production of male and female gametes of sufficient genetic difference and quality that, following syngamy, they result in embryos with genomic potential to allow for future adaptive change and the ability to respond to selective pressure. The fusion of dissimilar gametes resulting in the formation of a normal and viable embryo is known as anisogamy, and is concomitant with precise structural, physiological, and molecular control of gamete function for species survival. However, along the reproductive life cycle of all organisms, both male and female gametes can be exposed to an array of “stressors” that may adversely affect the composition and biological integrity of their proteins, lipids and nucleic acids, that may consequently compromise their capacity to produce normal embryos. The aim of this review is to highlight gamete genome organization, differences in the chronology of gamete production between the male and female, the inherent DNA protective mechanisms in these reproductive cells, the aetiology of DNA damage in germ cells, and the remarkable DNA repair mechanisms, pre- and post-syngamy, that function to maintain genome integrity.

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11

Russell, Scott D., and David D. Cass. "Ultrastructure of fertilization in Plumbago zeylanica." Acta Societatis Botanicorum Poloniae 50, no. 1-2 (2014): 185–89. http://dx.doi.org/10.5586/asbp.1981.029.

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The synergidless female gametophyte of <em>Plumbago zeylanica</em> receives the pollen tube through specialized cell wall ingrowths at the base of the egg; tube growth continues between egg and central cells. Pollen tube discharge occurs between egg and central cell and results in release of two male gametes, vegetative nucleus, and some pollen cytoplasm. Except for the location of gamete discharge, details of transmission and fusion of gametic nuclei appear to conform to reports of these processes in taxa possessing conventional embryo sacs.

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12

Nair, Sreelaja. "Maternal control of gamete choice during fertilization." International Journal of Developmental Biology 64, no. 1-2-3 (2020): 175–80. http://dx.doi.org/10.1387/ijdb.190156sn.

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Sexually reproducing organisms generate male and female haploid gametes, which meet and fuse at fertilization to produce a diploid zygote. The evolutionary process of speciation is achieved and maintained by ensuring that gametes undergo productive fusion only within a species. In animals, hybrids from cross-species fertilization events may develop normally, but are usually sterile (Fitzpatrick, 2004). Metazoan sperm and eggs have several features to ensure that the gametes, which have evolved independently and also in conflict with each other, are competent to undergo fertilization (Firman, 2018). Fertilization is a specific process that is ideally supposed to result in randomized fusion of compatible egg and sperm. Here, I will discuss key processes driven by maternal factors in the egg that dictate earliest stages of gamete recognition, gamete choice and fusion in metazoans.

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Crean, Angela J., and Simone Immler. "Evolutionary consequences of environmental effects on gamete performance." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1826 (April 19, 2021): 20200122. http://dx.doi.org/10.1098/rstb.2020.0122.

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Variation in pre- and post-release gamete environments can influence evolutionary processes by altering fertilization outcomes and offspring traits. It is now widely accepted that offspring inherit epigenetic information from both their mothers and fathers. Genetic and epigenetic alterations to eggs and sperm-acquired post-release may also persist post-fertilization with consequences for offspring developmental success and later-life fitness. In externally fertilizing species, gametes are directly exposed to anthropogenically induced environmental impacts including pollution, ocean acidification and climate change. When fertilization occurs within the female reproductive tract, although gametes are at least partially protected from external environmental variation, the selective environment is likely to vary among females. In both scenarios, gamete traits and selection on gametes can be influenced by environmental conditions such as temperature and pollution as well as intrinsic factors such as male and female reproductive fluids, which may be altered by changes in male and female health and physiology. Here, we highlight some of the pathways through which changes in gamete environments can affect fertilization dynamics, gamete interactions and ultimately offspring fitness. We hope that by drawing attention to this important yet often overlooked source of variation, we will inspire future research into the evolutionary implications of anthropogenic interference of gamete environments including the use of assisted reproductive technologies. This article is part of the theme issue ‘How does epigenetics influence the course of evolution?’

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14

Thomas, F. "PHYSICAL PROPERTIES OF GAMETES IN THREE SEA URCHIN SPECIES." Journal of Experimental Biology 194, no. 1 (September 1, 1994): 263–84. http://dx.doi.org/10.1242/jeb.194.1.263.

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Physical properties (density in kg m-3, viscosity, sinking rates and dispersion rate) of the gametes and associated spawned materials were measured for three species of sea urchin, Tripneustes gratilla, Echinometra mathaei and Colobocentrotus atratus, from habitats that differ in wave exposure. The gametes of all three species are negatively buoyant, highly viscous and exhibit shear-thinning (a decrease in viscosity with increasing shear rate). Female gametes are more viscous than male gametes, and the viscosity of female gametes differs among the three species. The viscosity of female gametes is highest for C. atratus, the species from habitats most exposed to wave action. Within the species T. gratilla, viscosity of female gametes is higher in habitats exposed to wave action than in more protected habitats. Evidence reported in this paper suggests that the shear-thinning of gametes may provide a performance advantage for these sea urchins. High viscosity of gametes at low shear rates may decrease gamete dispersal upon release and, under certain flow conditions, allow gametes to form strings and clumps on the surface of the urchin. Depending upon the morphology of the surface, these clumps or strings may be retained and fertilization may occur within these clumps or strings. Conversely, low viscosity of gametes at high shear rates decreases the power required to extrude gametes through the gonoduct during spawning.

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KNOX, R. B., S. Y. ZEE, C. BLOMSTEDT, and M. B. SINGH. "Male gametes and fertilization in angiosperms." New Phytologist 125, no. 4 (December 1993): 679–94. http://dx.doi.org/10.1111/j.1469-8137.1993.tb03917.x.

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Tian, H. Q., and S. D. Russell. "Micromanipulation of male and female gametes ofNicotiana tabacum: I. Isolation of gametes." Plant Cell Reports 16, no. 8 (May 1997): 555–60. http://dx.doi.org/10.1007/bf01142323.

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17

Picard, E. "The male gamete as a tool in the genetic improvement of cereals." Genome 31, no. 2 (January 15, 1989): 1005–13. http://dx.doi.org/10.1139/g89-175.

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This review surveys recent developments in the use of male gametes for the genetic improvement of cereals. It focuses mainly on the production of doubled haploids and their use in breeding programmes but also discusses gametoclonal variaton, in vitro selection through anther or pollen culture, and genetic transformation using the pollen tube as a vehicle for foreign DNA.Key words: male gamete, haploids, doubled haploids, cereals, gametoclonal variation, in vitro selection, pollen-mediated genetic transformation.

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Maan, S. S., and T. R. Endo. "Nucleocytoplasmic interactions stabilize ploidy level in wheat interspecific hybrids." Genome 34, no. 6 (December 1, 1991): 983–87. http://dx.doi.org/10.1139/g91-151.

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The cytoplasm of Aegilops squarrosa L. (2n = 14; DD) is compatible with the nuclei of Triticum aestivum L. (2n = 42; AABBDD) and the pentaploid F1 (2x = 35; AABBD), but not with the euploid nucleus of Triticum turgidum L. (2n = 28; AABB). To identify D-genome chromosomes with the genes conditioning differential nucleocytoplasmic compatibility, ae and sq 5x F1, having cytoplasms of T. aestivum and Ae. squarrosa, respectively, were reciprocally crossed to the seven doubled ditelosomics (d-dts) of the D-genome chromosomes (including four control crosses of d-dts 1A, 1B, and sq 5x F1). The 32 progeny were examined for the presence or absence of unpaired telosomes, monosomes, and the maximum number of bivalents at the meiotic metaphase I in the pollen mother cells for comparison with the transmission of ae and sq male and ae and sq female gametes carrying different numbers of D-genome chromosomes. The sq gametes with 1D, 5D, and other D-genome chromosomes had a strong functional advantage. In contrast, the ae gametes with 1D and other D genome chromosomes, except 5D, had a functional disadvantage. The sq and ae 5x F1 transmitted chromosome 5D through 80.0 and 72.2% of the male and 58.6 and 44.8% of the female gametes, respectively. We concluded that the sq gametes tended to increase and ae gametes tended to reduce the ploidy levels of the progeny.Key words: preferential gamete transmission, alloplasmic wheat, Triticum, Aegilops, polyploidy, aneuploidy.

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Sprunck, Stefanie. "Let's get physical: gamete interaction in flowering plants." Biochemical Society Transactions 38, no. 2 (March 22, 2010): 635–40. http://dx.doi.org/10.1042/bst0380635.

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Fertilization comprises a series of precisely orchestrated steps that culminate in the fusion of male and female gametes. The most intimate steps during fertilization encompass gamete recognition, adhesion and fusion. In animals, some binding-effector proteins and enzymes have been identified that act on the cell surfaces of the gametes to regulate gamete compatibility and fertilization success. In contrast, exploring plant gamete interaction during double fertilization, a characteristic trait of flowering plants, has been hampered for a long time because of the protected location of the female gametes and technical limitations. Over the last couple of years, however, the use of advanced methodologies, new imaging tools and new mutants has provided deeper insights into double fertilization, at both the cellular and the molecular level, especially for the model plant Arabidopsis thaliana. Most likely, one consequence of inventing double fertilization may be the co-evolution of special molecular mechanisms to govern each successful sperm delivery and efficient gamete recognition and fusion. In vivo imaging of double fertilization and the recent discovery of numerous female-gametophyte-specific expressed genes encoding small secreted proteins, some of whom were found to be essential for the fertilization process, support this hypothesis. Nevertheless, recent findings indicate that at least the membrane-merger step in plant gamete interaction may rely on an ancient and widely used gamete fusion system.

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Eckardt, Nancy A. "LORELEI: Guiding the Fate of Male Gametes." Plant Cell 20, no. 11 (November 2008): 2929. http://dx.doi.org/10.1105/tpc.108.201112.

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Tanaka, Ichiro. "Development of male gametes in flowering plants." Journal of Plant Research 106, no. 1 (March 1993): 55–63. http://dx.doi.org/10.1007/bf02344373.

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22

Schlegel, Peter N. "MICROMANIPULATION OF GAMETES FOR MALE FACTOR INFERTILITY." Urologic Clinics of North America 21, no. 3 (August 1994): 477–86. http://dx.doi.org/10.1016/s0094-0143(21)00621-2.

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23

Starr, R. C., F. J. Marner, and L. Jaenicke. "Chemoattraction of male gametes by a pheromone produced by female gametes of Chlamydomonas." Proceedings of the National Academy of Sciences 92, no. 2 (January 17, 1995): 641–45. http://dx.doi.org/10.1073/pnas.92.2.641.

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24

Tian, H. Q., and S. D. Russell. "Micromanipulation of male and female gametes of Nicotiana tabacum: I. Isolation of gametes." Plant Cell Reports 16, no. 8 (May 7, 1997): 555–60. http://dx.doi.org/10.1007/s002990050278.

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25

Sano, Y. "The genic nature of gamete eliminator in rice." Genetics 125, no. 1 (May 1, 1990): 183–91. http://dx.doi.org/10.1093/genetics/125.1.183.

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Abstract The two cultivated rice species, Oryza sativa and Oryza glaberrima, are morphologically alike but are reproductively isolated from each other by hybrid sterility. The hybrid is male sterile but partially female fertile. Backcross experiments were conducted to introduce an alien factor controlling hybrid sterility from O. glaberrima (W025) into O. sativa (T65wx) and examine the genetic basis. An extracted sterility factor, closely linked to the wx locus, induced gametic abortion due to allelic interaction and was tentatively designated as S(t). The segregation patterns for infertility was explained by assuming that W025 and T65wx carried S(t) and S(t)a, respectively, and gametes with S(t)a aborted only in the heterozygote (S(t)/S(t)a) although the elimination of female gametes was incomplete. Thus, S(t) seemed to be intermediate between a gamete eliminator and pollen killer. However, S(t) was proven to be likely the same as S1 which was formerly reported as gamete eliminator in a different genetic background of O. sativa. In addition, a chromosomal segment containing S1 (or S(t] caused a marked suppression of crossing over around it, suggesting the presence of an inversion. Further, female transmission of S1a increased as the segment containing S1 became small by recombination. After S1 was further purified by successive backcrosses up to the BC15 generation, it became pollen killer. The present results give evidence that a profound sterility gene such as gamete eliminator can be made from accumulation of pollen killer and its modifier(s) when pollen killer and modifier(s) are linked, they behave as a gene complex in the hybrid.

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Chenou, Éliane, Janine Kuligowski, and Michèle Ferrand. "Effets de faibles abaissements de température sur la différenciation de l'oosphère et sur les processus de fécondation chez le Marsilea vestita (Ptéridophytes)." Canadian Journal of Botany 63, no. 10 (October 1, 1985): 1753–61. http://dx.doi.org/10.1139/b85-246.

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Male and female gametes of Marsilea vestita were subjected to weak cooling periods (24° C/16° C or 24° C/12° C) of 1–4 h during the ultimate stage of gametogenesis. Effects of these suboptimal temperatures were observed on the organization of the oosphere on fertilization, and further development of the embryos. The changes observed varied with cold intensity and were proportional to the exposure time. The last steps of archegonogenesis were delayed (16° C) or even totally inhibited (12° C). The female gamete structure generally exhibited the following changes: the fertilization cone was enlarged, the cytoplasm more or less vacuolated, and organelles redistributed towards peripheral regions. Furthermore, the presence of chromatic fragments within the cytoplasm (12° C) suggests that the last division of female gametogenesis was strongly affected. In these gametes, fertilization was always reduced. When it occurred, the treatment considerably slowed down the different stages, allowing a better understanding of the male nucleus reactions during its migration. The percentage of embryos able to grow decreased proportionally to the length of cold exposure (16° C). After exposure of the gametes to 12° C, most embryos did not survive.

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Grini, Paul E., Arp Schnittger, Heinz Schwarz, Inge Zimmermann, Birgit Schwab, Gerd Jürgens, and Martin Hülskamp. "Isolation of Ethyl Methanesulfonate-Induced Gametophytic Mutants in Arabidopsis thaliana by a Segregation Distortion Assay Using the Multimarker Chromosome 1." Genetics 151, no. 2 (February 1, 1999): 849–63. http://dx.doi.org/10.1093/genetics/151.2.849.

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Abstract The life cycle of plants comprises two alternating generations, the diploid sporophyte (spore-bearing plant) and the haploid gametophyte (gamete-bearing plant). In contrast to animals, the postmeiotic cells give rise to haploid organisms whose function is to produce the gametes and to mediate fertilization. Analysis of gametophyte development and function has been hampered by the difficulty of identifying haplo-phase-specific mutants in conventional mutagenesis screens. Here we use a genetic strategy that is based on segregation distortion of nearby visible markers to screen for EMS-induced gametophytic mutants in Arabidopsis thaliana. Using the multiple marker chromosome mm1 we have isolated seven lines that displayed an altered segregation of markers. Reciprocal backcrosses of these lines showed a marked reduction of the transmission of the male and/or female gametes. Phenotypic analysis revealed that different aspects of either gametophytic development or function were affected. Three male gametophytic lines showed specific arrests during pollen development. One male gametophytic line was specifically defective in pollen tube elongation. Three gametophytic lines showed variable defects in both male and female gametophytic development.

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Russell, Scott D., Xiaoping Gou, Xiaoping Wei, and Tong Yuan. "Male gamete biology in flowering plants." Biochemical Society Transactions 38, no. 2 (March 22, 2010): 598–603. http://dx.doi.org/10.1042/bst0380598.

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Flowering plant reproduction is characterized by double fertilization, in which two diminutive brother sperm cells initiate embryo and endosperm. The role of the male gamete, although studied structurally for over a century at various levels, is still being explored on a molecular and cellular level. The potential of the male to influence development has been historically underestimated and the reasons for this are obvious: limitations provided by maternal imprinting, the much greater cellular volume of female gametes and the general paucity of paternal effects. However, as more is known about molecular expression of chromatin-modifying proteins, ubiquitin pathway proteins and transcription factors in sperm cells, as well as their ability to achieve effect by intaglio expression, passing transcripts directly into translation, the role of the male is likely to expand. Much of the expression in the male germline that appears to be distinct from patterns of pollen vegetative cell expression may be the result of chromosomal level regulation of transcription.

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Zhang, Ya Nan, Dong Mei Wei, En Ming He, Sen Miao, Hui Qiao Tian, and Scott D. Russell. "Isolation of Male and Female Gametes of Rice." Crop Science 50, no. 6 (November 2010): 2457–63. http://dx.doi.org/10.2135/cropsci2010.02.0066.

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Bucheeim, Mark A., and Larry R. Hoffman. "ULTRASTRUCTURE OF MALE GAMETES OF SPHAEROPLEA ROBUSTA (CHLOROPHYCEAE)." Journal of Phycology 22, no. 2 (June 1986): 176–85. http://dx.doi.org/10.1111/j.1529-8817.1986.tb00010.x.

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Buchheim, Mark A., and Larry R. Hoffman. "ULTRASTRUCTURE OF MALE GAMETES OF SPHAEROPLEA ROBUSTA (CHLOROPHYCEAE)." Journal of Phycology 22, no. 2 (June 1986): 176–85. http://dx.doi.org/10.1111/j.1529-8817.1986.tb04161.x.

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32

Bumstead, N., L. I. Messer, B. M. Freeman, and A. C. C. Manning. "Genetic transformation of chickens using irradiated male gametes." Heredity 58, no. 1 (February 1987): 25–30. http://dx.doi.org/10.1038/hdy.1987.4.

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33

Minhas, Brijinder. "Efficiency Enhancement of Manipulated Male and Female Gametes." Seminars in Reproductive Medicine 12, no. 03 (August 1994): 177–83. http://dx.doi.org/10.1055/s-2007-1016398.

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Smith, M. J., Q. V. Neri, T. T. Kanninen, Z. Rosenwaks, and G. D. Palermo. "Dynamic assessment of antioxidant capacity of male gametes." Fertility and Sterility 100, no. 3 (September 2013): S424. http://dx.doi.org/10.1016/j.fertnstert.2013.07.577.

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Russell, Scott D. "Attraction and transport of male gametes for fertilization." Sexual Plant Reproduction 9, no. 6 (November 1996): 337–42. http://dx.doi.org/10.1007/bf02441952.

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Russell, Scott D. "Attraction and transport of male gametes for fertilization." Sexual Plant Reproduction 9, no. 6 (November 28, 1996): 337–42. http://dx.doi.org/10.1007/s004970050052.

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Rivard, Sylvain R., Mario Cappadocia, and Benoit S. Landry. "A comparison of RFLP maps based on anther culture derived, selfed, and hybrid progenies of Solanum chacoense." Genome 39, no. 4 (August 1, 1996): 611–21. http://dx.doi.org/10.1139/g96-078.

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Comparative RFLP linkage maps were constructed using five segregating populations derived from two self-incompatible lines (termed PI 230582 and PI 458314) of diploid tuber-bearing Solanum chacoense Bitt. The analysis was based on 84 RFLP loci identified by 73 different cDNA clones. Distortion of expected Mendelian segregation ratios was observed; less than 10% of the markers showed a skewed segregation in the gametes forming the F1, hybrid population compared with 30% in the selfed population and 46 and 70% in the two populations produced by anther culture. For the anther culture derived populations, most of the skewed loci were scattered throughout the genome, whereas in the populations derived from selfing, they were found primarily in linkage group 1, around the S locus. In this study, we also found that the rate of meiotic recombination could differ between the male and female gametes produced by our parental lines. Thus, male gametes of line PI 458314 showed significantly less recombination as assessed by the total length of the map (206 cM for male gametes vs. 375 cM for female gametes) and the phenomenon was genome-wide. In contrast, the maps from the gametes of PI 230582 had about the same length, but some linkage groups were longer in the female gametes, while others were longer in the male gametes. Key words : Solanum chacoense, RFLP, anther culture, skewed segregation, self-incompatibility, sex differences in recombination.

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Grasso, Felicia, Stefania Mochi, Federica Fratini, Anna Olivieri, Chiara Currà, Inga Siden Kiamos, Elena Deligianni, et al. "A Comprehensive Gender-related Secretome of Plasmodium berghei Sexual Stages." Molecular & Cellular Proteomics 19, no. 12 (September 3, 2020): 1986–96. http://dx.doi.org/10.1074/mcp.ra120.002212.

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Plasmodium, the malaria parasite, undergoes a complex life cycle alternating between a vertebrate host and a mosquito vector of the genus Anopheles. In red blood cells of the vertebrate host, Plasmodium multiplies asexually or differentiates into gamete precursors, the male and female gametocytes, responsible for parasite transmission. Sexual stage maturation occurs in the midgut of the mosquito vector, where male and female gametes egress from the host erythrocytes to fuse and form a zygote. Gamete egress entails the successive rupture of two membranes surrounding the parasite, the parasitophorous vacuole membrane and the erythrocyte plasma membrane. In this study, we used the rodent model parasite Plasmodium berghei to design a label-free quantitative proteomic approach aimed at identifying gender-related proteins differentially released/secreted by purified mature gametocytes when activated to form gametes. We compared the abundance of molecules secreted by wild type gametocytes of both genders with that of a transgenic line defective in male gamete maturation and egress. This enabled us to provide a comprehensive data set of egress-related molecules and their gender specificity. Using specific antibodies, we validated eleven candidate molecules, predicted as either gender-specific or common to both male and female gametocytes. All of them localize to punctuate, vesicle-like structures that relocate to cell periphery upon activation, but only three of them localize to the gametocyte-specific secretory vesicles named osmiophilic bodies. Our results confirm that the egress process involves a tightly coordinated secretory apparatus that includes different types of vesicles and may put the basis for functional studies aimed at designing novel transmission-blocking molecules.

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NEAL, A. T., and J. J. SCHALL. "Gametocyte sex ratio in single-clone infections of the malaria parasite Plasmodium mexicanum." Parasitology 137, no. 13 (July 12, 2010): 1851–59. http://dx.doi.org/10.1017/s0031182010000909.

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SUMMARYSex ratio theory predicts that malaria parasites should bias gametocyte production toward female cells in single-clone infections because they will experience complete inbreeding of parasite gametes within the vector. A higher proportion of male gametocytes is favoured under conditions that reduce success of male gametes at reaching females such as low gametocyte density or attack of the immune system later in the infection. Recent experimental studies reveal genetic variation for gametocyte sex ratio in single-clone infections. We examined these issues with a study of experimental single-clone infections for the lizard malaria parasite Plasmodium mexicanum in its natural host. Gametocyte sex ratios of replicate single-clone infections were determined over a period of 3–4 months. Sex ratios were generally female biased, but not as strongly as expected under simple sex ratio theory. Gametocyte density was not related to sex ratio, and male gametocytes did not become more common later in infections. The apparent surplus of male gametocytes could be explained if male fecundity is low in this parasite, or if rapid clotting of the lizard blood reduces male gamete mobility. There was also a significant clone effect on sex ratio, suggesting genetic variation for some life-history trait, possibly male fecundity.

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Cass, David D. "Structural relationships among central cell and egg apparatus cells of barley as related to transmission of male gametes." Acta Societatis Botanicorum Poloniae 50, no. 1-2 (2014): 177–79. http://dx.doi.org/10.5586/asbp.1981.027.

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Barley embryo sacs were examined using light and electron microscopy before and during fertilization. One synergid degenerates after pollination with loss of nuclear and cytoplasmic organization and cell wall material between synergid and central cell. Some wall between egg and central cell is also lost. After pollen tube discharge into the degenerate synergid, the male gametes leave the synergid entering a pocket of central cell cytoplasm separated from the synergid only by membranes. This could provide for efficient gamete transmission and possible recognition through specific membrane contacts.

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Nagasato, Chikako, and Taizo Motomura. "Influence of the centrosome in cytokinesis of brown algae: polyspermic zygotes of Scytosiphon lomentaria (Scytosiphonales,Phaeophyceae)." Journal of Cell Science 115, no. 12 (June 15, 2002): 2541–48. http://dx.doi.org/10.1242/jcs.115.12.2541.

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We examined the relationship between the spindle orientation and the determination site of cytokinesis in brown algal cells using polyspermic zygotes of Scytosiphon lomentaria. When two male gametes fuse with one female gamete, the zygote has two pairs of centrioles derived from male gametes and three chloroplasts from two male and one female gametes. Just before mitosis, two pairs of centrioles duplicate and migrate towards the future mitotic poles. Spindle MTs develop and three or four spindle poles are formed. In a tri-polar spindle, one pair of centrioles shifts away from the spindle, otherwise, two pairs of centrioles exist adjoining at one spindle pole. Chromosomes arrange at several equators of the spindle. As a result of these multipolar mitoses, three or four daughter nuclei developed. Subsequently, these daughter nuclei form a line along the long axis of the cell. Cell partition always takes place between daughter nuclei, perpendicular to the long axis of the cell. Three or four daughter cells are produced by cytokinesis. Some of the daughter cells after cytokinesis do not have a nucleus, but all of them always contain the centrosome and chloroplast. Therefore, the number of daughter cells always coincides with the number of centrosomes or microtubule organizing centers (MTOCs). These results show that the cytokinetic plane in the brown algae is determined by the position of centrosomes after mitosis and is not dependent on the spindle position.

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Thomas, F., A. Schmidt-Rhaesa, and R. Poulin. "Microhabitat characteristics and reproductive status of male Euchordodes nigromaculatus (Nematomorpha)." Journal of Helminthology 73, no. 1 (January 1999): 91–93. http://dx.doi.org/10.1017/s0022149x99000141.

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In a sample of 61 free-living, postparasitic male Euchordodes nigromaculatus collected from a mountain stream in New Zealand, we found that only large males are found in areas of high current velocity. Thirty-five of the 61 males still contained gametes; these worms were found in wider, deeper, and slower-flowing parts of the stream relative to worms that had released their gametes. These results suggest that the physical characteristics of the immediate microhabitat of male worms can determine their probability of mating.

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Mariani, Anna, Prisca Campanoni, Silvia Gianì, and Diego Breviario. "Meiotic mutants of Medicago sativa show altered levels of α- and β-tubulin." Genome 43, no. 1 (February 1, 2000): 166–71. http://dx.doi.org/10.1139/g99-105.

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We have analysed the level of accumulation of α- and β-tubulin polypeptides in flowers collected from different meiotic mutants of alfalfa (Medicago sativa L.). The H33 mutant previously identified as a producer of male and female gametes with the somatic chromosome number (2n gametes) as a result of defective spindle orientation or, more rarely, abnormal cytokinesis, showed a higher level of α- and β-tubulin compared to control diploid plants and approximately the same level as control tetraploid plants. A higher level of tubulin was likewise observed in diploid plants displaying abnormalities in spindle orientation and cytokinesis, which had gone through 3-4 cycles of phenotypic recurrent selection to increase 2n gamete production. A similar analysis was performed on another class of Medicago meiotic mutants characterized by production of 4n pollen (jumbo pollen, due to the absence of cytokinesis at the end of meiosis) and 2n eggs. Again, the level of α- and β-tubulin was found to be higher in the mutants than in diploid controls. We conclude that meiotic defects, such as abnormal spindle orientation or cytokinesis leading to the formation of 2n gametes, determine an increased level of tubulin, the main constituent of plant microtubules (MTs). Key words: meiotic mutants, 2n gametes, cytoskeleton, α- and β-tubulin.

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Singh, Pallavi, Aditi Alaganan, Kunal R. More, Audrey Lorthiois, Sabine Thiberge, Olivier Gorgette, Micheline Guillotte Blisnick, et al. "Role of a patatin-like phospholipase in Plasmodium falciparum gametogenesis and malaria transmission." Proceedings of the National Academy of Sciences 116, no. 35 (August 14, 2019): 17498–508. http://dx.doi.org/10.1073/pnas.1900266116.

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Transmission of Plasmodium falciparum involves a complex process that starts with the ingestion of gametocytes by female Anopheles mosquitoes during a blood meal. Activation of gametocytes in the mosquito midgut triggers “rounding up” followed by egress of both male and female gametes. Egress requires secretion of a perforin-like protein, PfPLP2, from intracellular vesicles to the periphery, which leads to destabilization of peripheral membranes. Male gametes also develop flagella, which assist in binding female gametes for fertilization. This process of gametogenesis, which is key to malaria transmission, involves extensive membrane remodeling as well as vesicular discharge. Phospholipase A2 enzymes (PLA2) are known to mediate membrane remodeling and vesicle secretion in diverse organisms. Here, we show that a P. falciparum patatin-like phospholipase (PfPATPL1) with PLA2 activity plays a key role in gametogenesis. Conditional deletion of the gene encoding PfPATPL1 does not affect P. falciparum blood stage growth or gametocyte development but reduces efficiency of rounding up, egress, and exflagellation of gametocytes following activation. Interestingly, deletion of the PfPATPL1 gene inhibits secretion of PfPLP2, reducing the efficiency of gamete egress. Deletion of PfPATPL1 also reduces the efficiency of oocyst formation in mosquitoes. These studies demonstrate that PfPATPL1 plays a role in gametogenesis, thereby identifying PLA2 phospholipases such as PfPATPL1 as potential targets for the development of drugs to block malaria transmission.

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Pennec, Marcel Le, and Peter G. Beninger. "Ultrastructural characteristics of spermatogenesis in three species of deep-sea hydrothermal vent mytilids." Canadian Journal of Zoology 75, no. 2 (February 1, 1997): 308–16. http://dx.doi.org/10.1139/z97-039.

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To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.

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Saez, Fabrice, and Joël R. Drevet. "Dietary Cholesterol and Lipid Overload: Impact on Male Fertility." Oxidative Medicine and Cellular Longevity 2019 (December 6, 2019): 1–11. http://dx.doi.org/10.1155/2019/4521786.

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Lipid metabolic disorders due to poor eating habits are on the rise in both developed and developing countries, with a negative impact of the “Western diet” on sperm count and quality. Dietary lipid imbalance can involve cholesterol, fatty acids, or both, under different pathophysiological conditions grouped under the term dyslipidemia. The general feature of dyslipidemia is the development of systemic oxidative stress, a well-known deleterious factor for the quality of male gametes and associated with infertility. Sperm are particularly rich in polyunsaturated fatty acids (PUFA), an important characteristic associated with normal sperm physiology and reproductive outcomes, but also targets of choice for oxidative thrust. This review focuses on the effects of dietary cholesterol or different fatty acid overload on sperm composition and function in both animals and humans. The links between oxidative stress induced by dyslipidemia and sperm dysfunction are then discussed, including possible preventive or therapeutic strategies to preserve gamete quality, longevity when stored in cryobanking, and male fertility.

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Nagamatsu, Go, and Katsuhiko Hayashi. "Stem cells, in vitro gametogenesis and male fertility." Reproduction 154, no. 6 (December 2017): F79—F91. http://dx.doi.org/10.1530/rep-17-0510.

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Reconstitution in culture of biological processes, such as differentiation and organization, is a key challenge in regenerative medicine, and one in which stem cell technology plays a central role. Pluripotent stem cells and spermatogonial stem cells are useful materials for reconstitution of germ cell development in vitro, as they are capable of differentiating into gametes. Reconstitution of germ cell development, termed in vitro gametogenesis, will provide an experimental platform for a better understanding of germ cell development, as well as an alternative source of gametes for reproduction, with the potential to cure infertility. Since germ cells are the cells for ‘the next generation’, both the culture system and its products must be carefully evaluated. In this issue, we summarize the progress in in vitro gametogenesis, most of which has been made using mouse models, as well as the future challenges in this field.

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Verlhac, Marie-Hélène, and Marie-Emilie Terret. "Oocyte Maturation and Development." F1000Research 5 (March 9, 2016): 309. http://dx.doi.org/10.12688/f1000research.7892.1.

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Sexual reproduction is essential for many organisms to propagate themselves. It requires the formation of haploid female and male gametes: oocytes and sperms. These specialized cells are generated through meiosis, a particular type of cell division that produces cells with recombined genomes that differ from their parental origin. In this review, we highlight the end process of female meiosis, the divisions per se, and how they can give rise to a functional female gamete preparing itself for the ensuing zygotic development. In particular, we discuss why such an essential process in the propagation of species is so poorly controlled, producing a strong percentage of abnormal female gametes in the end. Eventually, we examine aspects related to the lack of centrosomes in female oocytes, the asymmetry in size of the mammalian oocyte upon division, and in mammals the direct consequences of these long-lived cells in the ovary.

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Ribeiro, João C., David F. Carrageta, Raquel L. Bernardino, Marco G. Alves, and Pedro F. Oliveira. "Aquaporins and Animal Gamete Cryopreservation: Advances and Future Challenges." Animals 12, no. 3 (February 2, 2022): 359. http://dx.doi.org/10.3390/ani12030359.

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Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing procedures may strongly impair the gamete function. The correct cryopreservation procedure is characterized by the balance between freezing rate and cryoprotective agents (CPAs), which minimizes cellular dehydration and intracellular ice formation. For this purpose, osmoregulation is a central process in cryopreservation. During cryopreservation, water and small solutes, including penetrating cryoprotective agents, cross the plasma membrane. Aquaporins (AQPs) constitute a family of channel proteins responsible for the transport of water, small solutes, and certain gases across biological membranes. Thirteen homologs of AQPs (AQP0-12) have been described. AQPs are widely distributed throughout the male and female reproductive systems, including the sperm and oocyte membrane. The composition of the male and female gamete membrane is of special interest for assisted reproductive techniques (ART), including cryopreservation. In this review, we detail the mechanisms involved in gamete cryopreservation, including the most used techniques and CPAs. In addition, the expression and function of AQPs in the male and female gametes are explored, highlighting the potential protective role of AQPs against damage induced during cryopreservation.

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Faris, J. D., B. Laddomada, and B. S. Gill. "Molecular Mapping of Segregation Distortion Loci in Aegilops tauschii." Genetics 149, no. 1 (May 1, 1998): 319–27. http://dx.doi.org/10.1093/genetics/149.1.319.

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Abstract Distorted segregation ratios of genetic markers are often observed in progeny of inter- and intraspecific hybrids and may result from competition among gametes or from abortion of the gamete or zygote. In this study, 194 markers mapped in an Aegilops tauschii F2 population were surveyed for distorted segregation ratios. Region(s) with skewed segregation ratios were detected on chromosomes 1D, 3D, 4D, and 7D. These distorter loci are designated as QSd.ksu-1D, QSd.ksu-3D, QSd.ksu-4D, and QSd.ksu-7D. Three regions of segregation distortion identified on chromosome 5D were analyzed in two sets of reciprocal backcross populations to analyze the effect of sex and cytoplasm on segregation distortion. Extreme distortion of marker segregation ratios was observed in populations in which the F1 was used as the male parent, and ratios were skewed in favor of TA1691 alleles. There was some evidence of differential transmission caused by nucleo-cytoplasmic interactions. Our results agree with other studies stating that loci affecting gametophyte competition in male gametes are located on 5DL. The distorter loci on 5DL are designated as QSd.ksu-5D.1, QSd.ksu-5D.2, and QSd.ksu-5D.3.

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Journal articles on the topic 'Male gametes'

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