Attitude and willingness on gamete donation among medical students:An experience from a state university in Sri Lanka

Objective:To assess the attitude and willingness of medical students of the Faculty of Medicine,University of Jaffna,regarding gamete donation.Methods:An institutional-based descriptive cross-sectional study was conducted at the Faculty of Medicine,University of Jaffna,from September 2022 to May 2023 among undergraduate medical students who gave their voluntary participation.A self-administered questionnaire was used as a study instrument to collect data regarding their attitude and willingness toward gamete donation.Results:A total of 345 participants were recruited and their sociodemographic data revealed that 56.8%of the participants were female,62.3%aged between 26 and 30 years,and 92.2%were unmarried.Many of them received information regarding gamete donations during their clinical appointments.Over half(67.8%)of them showed a negative attitude towards gamete donation.Regarding willingness,only 39.7%of participants had a positive approach for being a gamete donor;among them,84.7%preferred anonymous donations.Religion and ethnicity had a significant influence on their attitudes and willingness.In addition,male was also found to be more willing to donate gametes.Conclusions:Most medical students have negative views about gamete donation.Imparting awareness and knowledge of assisted reproductive technology and gamete donation within medical students'sociocultural and ethical backgrounds might facilitate a change in attitude towards gamete donation amongst future medical practitioners.

The Overwintering Capability of Ulva prolifera Spores and Gametes in the Yellow Sea,China

Green tides caused by the bloom of Ulva prolifera have affected the Yellow Sea annually since 2007.To explore the intrinsic causes of successive blooms,field investigations and indoor simulation experiments were conducted using micro-propagules of U.prolifera.From January to February 2014,micro-propagules of various green algae,including U.prolifera,Ulva flexuosa,and Ulva linza,were prevalent in the coastal waters of Rudong,Lianyungang,and Qingdao.However,in March 2014,micro-propagules of U.prolifera were not detected in the coastal waters of Lianyungang and Qingdao.Neither the spores nor gametes of U.prolifera can germinate at temperatures below 5℃.At 2℃and 5℃,U.prolifera spores and gametes could survive for 1-3 months at a light intensity range of 0-30μmol m^(-2)s^(-1)and for less than 1 month if the light intensity exceeded 30μmol m^(-2)s^(-1).By integrating indoor experiments and field investigations,this study found that U.prolifera spores and gametes could overwinter in the Rudong coastal area,which is an important factor for the annual emergence of recurring green tides in the Yellow Sea.

Relationship between chromatin organization, mRNAs profile and human male gamete quality

Spermiogenesis is a complex process leading to the formation of motile spermatozoa characterized by a highly stable chromatin compaction that transfers the paternal genome into the oocyte. It is commonly held that these haploid cells are devoid of transcriptional and translational activities and that the transcripts represent remnants of stored mRNAs. Recently, the chromatin organization of mature spermatozoa has been revisited as a double nucleoprotamine-nucleohistone structure possessing less-condensed regions sensitive to nuclease activity, which could be implicated in the expression of genes involved in the early embryo development. The existence of a complex population of mRNAs in human sperm is well-documented, but their role is not yet elucidated. Evidence for a latent transcriptional capacity and/or a potential de novo translation in mature spermatozoa from fertile men are essential for understanding the last steps of sperm maturation, such as capacitation and acrosome reaction. As such, we have documented the relationship between sperm quality and the distribution of sperm RNAs by showing divergent levels of transcripts encoding for proteins involved in either nuclear condensation （protamines 1 and 2） or in capacitation （eNOS and nNOS, c-myc） or in motility and sperm survival （aromatase） between low and high motile sperm issued from the same sample. Therefore, analyzing the profile of mRNAs could be helpful either as a diagnostic tool for evaluating male fertility after spermatogenesis or for prognosis use for fertilization.

Studies on the Formation and Transmission of n + 1 Gametes of Cabbage Primary Trisomics

The transmission rate of n ＋ 1 gamete is an important parameter for the genetic analysis of trisomics. To correctly use the trisomics of the cabbage to carry out gene orientation and other genetic studies, the n ＋ 1 gamete transmission rates by female parent and by male parent were determined. The results showed that the n ＋ 1 gamete transmission rates were 15.28% for tri-1, 12.68% for tri-2, 12.31% for tri-3, 30.51% for tri-4, 22.81% for tri-5, 7.46% for tri-6, 5.36% for tri-7, 42.37% for tri-8, and 9.23% for tri-9 by female parent, and were 12.12% for tri-1, 12.33% for tri-2, 7.81% for tri-3, 4.76% for tri-4, 8.93% for tri-5, 10.94% for tri-6, 1.54% for tri-7, 2.94% for tri-8, and 13.04% for tri-9 by male parent. The main factors affecting the male n ＋ 1 gamete formation and transmission were the rate of trivalent formation at prophase Ⅰ, the rate of 9-9-10-10 division at anaphase Ⅱ, and the pollen viability.

Impact of gamete health on fertilization and embryo development: An overview

A genetically and functionally proficient gamete is essential for normal fertilization and embryonic development.Any change in gamete health affects fertilization and subsequent events,including embryonic development,implantation,and successful pregnancy.This present review focuses on the role of gamete health on fertilization and embryo development.Several conventional and advanced methods are used to evaluate the morphology and functions of gametes.The abnormal spermatozoa adversely affect fertilization events,which results in reduced cleavage/blastocyst/implantation and pregnancy rate during assisted reproductive techniques.Poor oocyte quality is also one of the reasons for infertility,although the oocyte has an innate capacity to repair a certain amount of abnormality of both oocyte and spermatozoa.Therefore,oocyte health carries more responsibilities during fertilization events.The gamete,either spermatozoa or oocyte,should have optimum morphological and functional health to fertilize and develop a competent embryo successfully.Thus,it is of prime importance to consider the gamete health parameters while dealing with infertility.

Cytological Studies on Unreduced Gamete Formation of Strawberries (Fragaria)

A diploid strawberry (Fragaria vesca L.) which can naturally produce unreduced gametes (2n pollen) and doubled-unreduced gametes (4n pollen) was used to study the cytological mechanism of 2n and 4n gamete formation. The result showed that the formation of 2n gamete was mainly due to the abnormal orientation of spindles at metaphase II. The normal orientation of two spindles at metaphase I was perpendicular to each other, which led to tetrad formation at the end of meiosis. Two kinds of abnormal orientation of metaphase II spindles, i. e. parallel spindles and triangle spindles, were observed. Of the parallel spindles, the 4 group chromosomes were distributed to 2 poles and formed a dyad which formed two 2n pollen grains further-ly. Of the triangle spindles, the 4 group chromosomes were distributed to 3 poles and formed a triad which formed one 2n pollen grain and two n pollen grains. In addition, a few very big pollen grains (4n pollen) which probably due to the fusion of the tetrad were found.

Understanding the Mechanism of Gamete Release in <i>Sargassum vulgare</i>C. Agardh

Sargassum vulgare C. Agardh shows androgynous receptacles, each bearing on an average 12 unisexual conceptacles which open outside by ostiole, and wherein gametangia (antheridia or oogonia) lie interspersed with paraphyses. Since out-put of eggs is extremely low, 4 - 6 per female conceptacle, Sargassum sp. ensures its survival under all eco-physiological conditions. The released oogonium is “wrapped” in sulphated polysaccharide-rich wall layer known to provide protection against desiccation. Oogonia after being “extruded” out of ostiole, are “incubated” on receptacle, where they grow into eggs that are easily contacted by spermatozoids. Gamete release is synchronous and almost simultaneous ensuring high rates of fertilization. The release occurs on days falling near a full moon or new moon, during low tides when conceptacles lie exposed. Gamete release occurs first from upper conceptacles, which “house” mature gametangia while lower ones are still developing. This results in gamete release over an extended period of time. The zygote dispersal and propagule recruitment also show adaptations selectively advantageous for the alga.

Acceptability of Gametes Donation in Cote d’Ivoire

Introduction: The need for childbearing is greater in Sub-Saharan countries for socio-cultural reasons. In fact, it is correlated to the need for the transmission of one’s own genes. That is why the assisted reproductive technology with a third party donor can be considered as proxy procreation and can be rejected. Methods: All female patients who consulted for a childbearing desire and who needed an assisted reproductive technology with a third party donor were included in the study held at the university teaching hospital of Yopougon and in a private clinic from 1 September 2014 to 31 October 2015. 100 couples were included. Results: 82% of the men accepted the gametes donation in their couple and 89% of women did. 54% of the men accepted the donation spontaneously and 66% of the women too. The others were reserved before accepting it finally. The reasons for this reserved attitude regarding the donation were mainly the need to reflect for the men and the necessity to seek for their partner’s opinion concerning the women. Conclusion: The rate of acceptability of the gametes donation is very high in C?te d’Ivoire in spite of the cultural perception of the genes transmission.

Factors Influencing the Acceptance of the Gametes Donation in Cote d’Ivoire/West Africa

Introduction: Africans ensure their offspring by transmitting their own genes. Even if adoption is a common thing in Africa, the biological kinship keeps its supremacy. The following study tries to identify socio-cultural factors that may influence the couples’ attitude towards the gametes donation. Methods: All female patients consulting for a childbearing desire and with an indication of an assisted reproductive technique with a third donor, were included in this longitudinal retrospective and prospective study at the teaching hospital of Yopougon and in a private clinic from 1st September 2014 to 31 October 2015. 100 couples were included. Chi square test was used for statistics data. The following factors were analyzed: age, sex, religion, profession, anterior procreation, existence of a common child, infertility duration. Results: Only the age had a significant link with the egg donation refusal rate. Conclusion: This work makes it possible to foresee that Africans have the same conception of procreation because one finds this desire of childbearing in all the layers of the society.

Do egg cell-secreted aspartic proteases promote gamete attachment?

During the double fertilization process of flowering plants(angiosperms),pollen tubes transport a pair of immobile sperm cells toward and inside the embryo sac for fusion with egg and central cell,respectively.Male–female gamete interactions during fertilization are critical for reproductive success and seed development,and thus have interested biologists for decades.Compared to animals,little is known about gamete interaction mechanisms in angiosperms.

Determination of n+1 Gamete Transmission Rate of Trisomics and Location of Gene Controlling 2n Gamete Formation in Chinese Cabbage(Brassica rapa)

A set of trisomics of Chinese cabbage was used for determining the n-I-1 gamete transmission rate and locating the gene controlling 2n gamete formation on the corresponding chromosome. The results showed that the transmission rates of extra chromosomes in different trisomics varied from 0% to 15.38% by male gametes and from 0% to 17.39% by female gametes. Of the nine F2 populations derived from the hybridizations between each trisomic and Bp058 （2n gamete material）, only Tri- 4xBp058 showed that the segregation ratio of plants without 2n gamete formation to plants with 2n gamete formation was 10.38：1, which fitted the expected segregation ratio of the trisomics （AAa） based on the 7.37% of n＋l gamete transmission through female and 5.88% through male. In other populations the segregation ratios varied from 2.48：1 to 3.72：1, which fitted the expected 3：1 segregation ratio of the bisomics （Aa）. These results suggested that the gene controlling 2n gamete formation in Chinese cabbage Bp058 was located on chromosome 4. Further trisomic analysis based on the chromosome segregation and the incomplete stochastic chromatid segregation indicated that the gene locus was tightly linked to the centromere.

Advances in research into gamete and embryo-fetal origins of adult diseases

The fetal and infant origins of adult disease hypothesis proposed that the roots of adult chronic disease lie in the effects of adverse environments in fetal life and early infancy. In addition to the fetal period, fertilization and early embryonic stages, the critical time windows of epigenetic reprogramming, rapid cell differentiation and organogenesis, are the most sensitive stages to environmental disturbances. Compared with embryo and fetal development, gametogenesis and maturation take decades and are more vulnerable to potential damage for a longer exposure period. Therefore, we should shift the focus of adult disease occurrence and pathogenesis further back to gametogenesis and embryonic development events, which may result in intergenerational, even transgenerational, epigenetic re-programming with transmission of adverse traits and characteristics to offspring. Here, we focus on the research progress relating to diseases that originated from events in the gametes and early embryos and the potential epigenetic mechanisms involved.

Inducement of chromosome translocation with small alien segments by irradiating mature female gametes of the whole arm translocation line

Haynaldia villosa Schur. (syn. Dasypyrum villosum Candargy, 2n=14, VV) has been proved to be an important genetic resource for wheat improvement. The development of translocation with small alien chromosome segments, especially interstitial translocation, will be helpful for better utilization of its useful genes. Up to now, most of the reported Triticum aestivum – H. villosa translocation lines are involved in a whole arm or large alien fragments. In this paper, we report a highly efficient approach for the creation of small chromosome segment translocation lines. Before flowering, the female gametes of wheat-H. villosa 6VS/6AL translocation line were irradiated by 60CO-γ ray at 160 Rad/M dosage rate and three dosages (1600, 1920, 2240 Rad). Anthers were removed from the irradiated florets on the same day and the florets were pollinated with normal fresh pollens of T. aestivum cv. Chinese Spring after 2-3 days. Genomic in situ hybridization (GISH) at mitosis metaphase of root-tip cell of M1 plants was used to detect the chromosome structural changes involving 6VS of H. villosa. Among the 534 M1 plants screened, 97 plants contained small segment chromosome structural changes of 6VS, including 80 interstitial translocation chromosomes, 57 terminal translocation chromosomes and 55 deletion chromosomes. For the 2240 Rad dosage treatment, the inducement frequencies of interstitial translo-cation, terminal translocation and deletion were 21.02%, 14.01%, and 14.65%, respectively, which were much higher than those previously reported. The M2 seeds were obtained by backcrossing of 74 M1 plants involving 146 chromosomes structural changes of 6VS, and it was found that the structural aberrations in the M1 plants could be transmitted to their progenies. Irradiating mature female gametes of whole arm translocation is a new and highly efficient approach for creation of small segment chromosome struc-tural changes, especially for interstitial translocations.

A reciprocal inhibition between ARID1 and MET1 in male and female gametes in Arabidopsis

Both female and male gametophytes harbor companion cells and gametes. MET1, a DNA methyltransferase, is down-regulated in companion cells. However, how MET1 is differentially regulated in gametophytes remains unexplored. ARID1, a transcription factor that is specifically depleted in sperm cells, is occupied by MET1- dependent CG methylation. Here, we show that MET1 confines ARID1 to the vegetative cell of male gametes, but ARID1 conversely represses MET1 in the central cell of female gametes. Compared to the vegetative celllocalization in wild type pollen, ARID1 expands to sperm cells in the met1 mutant. To understand whether MET1- dependent ARID1 inhibition exists during female gametogenesis, we first show that ARID1 is expressed in the megaspore mother cell （MMC）, ARID1 but not MET1 is detectable in the central cell at maturity. Interestingly, compared to the absence of MET1 in the central cell and the egg cell of wild type ovules, MET1 significantly accumulates in these two cells in aridl ovules. Lastly, we show that both ARIDI and METI are required for the cell specification of MMC. Collectively, our results uncover a reciprocal dependence between ARIDI and METI, and provide a clue to further understand how the specification of MMC is likely regulated by DNA methylation.

Gamete Dialogs in Green Lineages

Gamete fusion is a core process of sexual reproduction and, in both plants and animals, different sex gametes fuse within species. Although most of the molecular factors involved in gamete interaction are still unknown in various sex-possessing eukaryotes, reports of such factors in algae and land plants have been increasing in the past decade. In particular, knowledge of gamete interaction in flowering plants and green algae has increased since the identification of the conserved gamete fusion factor GENERATIVE CELL SPECIFIC 1/HAPLESS 2 （GCS1/HAP2）. GCSl was first identified as a pollen generative cell-specific transmembrane protein in the lily （Lilium Iongiflorum）, and was then shown to function not only in flowering plant gamete fusion but also in various eukaryotes, including unicellular protists and metazoans. In addition, although initially restricted to Chlamydomonas, knowledge of gamete attachment in flowering plants was also acquired. This review focuses on recent progress in the study of gamete interaction in volvocine green algae and flowering plants and discusses conserved mechanisms of gamete recognition, attachment, and fusion leading to zygote formation.

Egg CD9 protein tides correlated with sperm oscillations tune the gamete fusion ability in mammal

Mammalian fertilization involves membrane events-adhesion,fusion,sperm engulfment,membrane block to polyspermy-whose causes remain largely unknown.Recently,specific oscillations of the sperm in contact with the egg were shown to be necessary for fusion.Using a microfluidic chip to impose the venue for the encounter of two gametes allowed real-time observation of the membrane remodelling occurring at the sperm/egg interface.The spatiotemporal mapping of egg CD9 revealed that this protein concentrates at the egg/sperm interface as a result of sperm oscillations,until a CDg-rich platform is nucleated on which fusion immediately takes place.Within 2-5 min after fusion,most of the CD9 leaves the egg for the external aqueous medium.Then an egg membrane wave engulfs the sperm head in^25 min.These results show that sperm oscillations initiate the CD9 recruitment that causes gamete fusion after which CD9 and associated proteins leave the membrane in a process likely to contribute to block polyspermy.They highlight that the gamete fusion story in mammals is an unexpected interplay between mechanical constraints and proteins.

Pollen-Ovule Ratio and Gamete Investment in Pedicularis （Orobanchaceae）

The Pedicularis species provides ideal materials to study floral evolution because of their substantial flower variation based on a narrow genetic basis, even though they are almost exclusively pollinated by bumblebee. These traits allow us to detect the evolutionary trends of floral parameters without considering genetic background and the difference of pollination vectors. The pollen-ovule ratio is widely used to estimate the pattern of resource investment in two sexual functions in flowering plants. Forty species representing all of the corolla types in Pedicularls were used to study pollen-ovule ratio, gamete investment, and their correlations. Results show that pollen-ovule ratio does not differ among both different corolla types and taxonomic groups. It is therefore suggested that pollen-ovule ratio should be a parallel evolution. The correlations between pollen-ovule ratio and pollen size （-）, and ovule size （＋） can be successfully explained in terms of sex allocation theory. The biological significance of such relationships was also discussed. Additionally, we analyzed the pattern of resource investment into female gamete, which has been somewhat neglected, and found that plants have different patterns of gamete investment between the two sexual functions.

Gamete Recognition in Higher Plants:An Abstruse but Charming Mystery

Although much effort has been made to uncover the mechanism underlying double fertilization, little knowledge has been acquired for understanding the molecular base of gamete recognition, mainly because of technical limitations. Still, progress has been made in terms of the mechanism, including the identification of candidate molecules that are involved in gamete recognition in angiosperms. New cues for gamete recognition have been found by the successful separation of the gametes and construction of gamete-specific cDNA libraries in several species, and the application of molecular approaches for studying this process by mutations. Thus, the topic is considered an abstruse but charming mystery.

Egg cell-secreted aspartic proteases ECS1/2 promote gamete attachment to prioritize the fertilization of egg cells over central cells in Arabidopsis

Double fertilization is an innovative phenomenon in angiosperms,in which one sperm cell first fuses with the egg cell to produce the embryo,and then the other sperm fuses with the central cell to produce the endosperm.However,the molecular mechanism of the preferential fertilization of egg cells is poorly understood.In this study,we report that two egg cell-secreted aspartic proteases,ECS1 and ECS2,play an important role in promoting preferential fertilization of egg cells in Arabidopsis.We show that simultaneous loss of ECS1 and ECS2 function resulted in an approximately 20%reduction in fertility,which can be complemented by the full-length ECS1/2 but not by corresponding active site mutants or by secretion-defective versions of ECS1/2.Detailed phenotypic analysis revealed that the egg cellsperm cell attachment was compromised in ecs1 ecs2 siliques.Limited pollination assays with cyclin-dependent kinase a1(cdka;1)pollen showed that preferential egg cell fertilization was impaired in the ecs1 ecs2 mutant.Taken together,these results demonstrate that egg cells secret two aspartic proteases,ECS1 and ECS2,to facilitate the attachment of sperm cells to egg cells so that preferential fertilization of egg cells is achieved.This study reveals the molecular mechanism of preferential fertilization in Arabidopsis thaliana.

Cryopreservation of farm animal gametes and embryos:recent updates and progress

Cryopreservation has undergone tremendous advances and is widely used in animal production based on decades of study of cellular permeability, freezability and empirical generalization. Several improvement are particularly important: the cryopreservation protocol has been continuously re?ned over the years to achieve greater reproductive performance; cryoprotective agents are more effective and less toxic than previously; there has been signi?cant innovation in advanced cryopreservation systems and carriers. Despite this, there are still problems that urgently require practical solutions, such as remedies for cryodamage and encouraging the use of frozen–thawed porcine sperm in pig production.