Sex Gamete Research Articles

Oocyte Donation: Three Perspectives

Background: A number of important problems remain unresolved in the field of assisted reproductive technologies (ART) using germ cells from a single donor. This study aimed to assess attitudes about the use of sex gamete donation in ART in different social groups including medical workers, oocyte recipients, and oocyte donors.
 Methods: To achieve this goal, we surveyed 286 participants from seven countries. Of them, 190 were medical workers from ART clinics (respondents from seven countries), 45 were oocyte recipients (Kazakhstan), and 51 were oocyte donors (Kazakhstan).
 Results: A survey of the three groups showed that issues related to donor health were most common in the donor selection process based on patient and doctor distrust of the health care system. The main motive for oocyte donation was financial compensation, which draws attention to the social disadvantage of the donor population. Medical workers with more than 5 years of work experience (79.7%) supported the use of programs tracking donor sex gametes and limiting the use of oocyte donors.
 Conclusions: The willingness and consent of the surveyed medical workers and oocyte recipients to use the donor material and create a unified registry of donor sex gametes demonstrates the importance of this issue.

Isolation of GFP-tagged plasma membrane protein from Arabidopsis egg cells.

Angiosperms possess a double fertilization system for sexual reproduction. Double fertilization is regulated by interactions among proteins localized in the plasma membrane of each sex gamete. A few plasma membrane resident proteins regulating double fertilization have been identified in male gametes. In contrast, no fertilization regulators in female gamete plasma membrane have been identified, largely due to difficulties in the isolation and collection of female gametes. We had produced Arabidopsis transgenic plant pDD45::GFP-AtPIP2;1 where the egg cell plasma membrane was specifically labeled with GFP (Igawa et al. 2013). The protein extract derived from approximately 200 pistils, which contained unfertilized and mature egg cells, was subjected to immunoprecipitation using anti-GFP antibody. As a result, both GFP and AtPIP2;1 were specifically detected in immunoprecipitated proteins from pistil tissues of pDD45::GFP-AtPIP2;1 transgenic plant, but not in those of wild type pistils. It was revealed that specific proteins expressed in the egg cells were successfully isolated from pistil cell population. The method described here showed the feasibility of isolating specific egg cell plasma membrane protein without gamete isolation and collection procedures.

Spermatozeugmata structure and dissociation of the Australian flat oyster Ostera angasi: Implications for reproductive strategy.

Variation in reproductive strategy is one of the key factors contributing to recruitment success of molluscs in different habitats. Spermcasting is a unique mode in mollusc reproduction where males produce spermatozeugmata, a radially arrayed sperm cluster wrapped by gelatinous membrane. In this study, spermatozeugmata structure and their dissociation in the Australian flat oyster Ostrea angasi were investigated to elucidate the reproductive strategy in spermcasting molluscs. The histological observation indicated that spermatogonia gradually aggregated in the gonad follicle at the early gonad development stages and developed into spermatozeugmata and became tightly packed at the advanced stages. Even though mature male and female gametes could be found in a hermaphroditic individual, the animal may prevent self-fertilization by shedding different sex gametes at different time. The O. angasi sperm are similar in size and shape to broadcasting oysters, but have one additional mitochondrion. Variations in maintaining spermatozeugmata integrity and sperm motility between individuals depended on the level of masculinity or femineity. The durations of spermatozeugmata dissociation and sperm viability were longer in males than in hermaphrodites. The unique structure and capability for spermatozeugmata to maintain the functional integrity after spawning have adaptive significance for fertilization and gamete dispersal in this species.

How Men and Women Respond to Hypothetical Parental Discovery: The Importance of Genetic Relatedness

Paternal uncertainty has shaped human behavior both in evolutionary and cultural terms. There has been much research investigating parenting as a function of genetic relatedness to the child, with a focus on male behavior, but the nature of these sex differences is hard to evaluate. We devised a hypothetical scenario that was as similar as possible for men and women to test whether, even in such a scenario, sex differences would remain strong. Participants were presented with the discovery that a child that s/he believed to be theirs was not carrying their own genes. Irrespective of sex, participants (n = 1007) were more upset when the baby was not genetically related to them than when the child was genetically related but the sex gamete was not from a chosen donor. Women were more upset than men in both scenarios, but were more likely to want to keep the baby. The results are discussed with reference to evolved and rational mechanisms affecting parenting.

SERK and APOSTART. Candidate Genes for Apomixis in Poa pratensis

Seed production generally requires the mating of opposite sex gametes. Apomixis, an asexual mode of reproduction, avoids both meiotic reduction and egg fertilization. The essential feature of apomixis is that an embryo is formed autonomously by parthenogenesis from an unreduced egg of an embryo sac generated through apomeiosis. If apomixis were well understood and harnessed, it could be exploited to indefinitely propagate superior hybrids or specific genotypes bearing complex gene sets. A more profound knowledge of the mechanisms that regulate reproductive events would contribute fundamentally to understanding the genetic control of the apomictic pathway. In Poa pratensis, we isolated and characterized two genes, PpSERK (SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE) and APOSTART. These full-length genes were recovered by rapid amplification of cDNA ends and their temporal and spatial expression patterns were assessed by reverse transcription-polymerase chain reaction and in situ hybridization, respectively. The expression of PpSERK and APOSTART differed in apomictic and sexual genotypes. Their putative role in cell-signaling transduction cascades and trafficking events required during sporogenesis, gametogenesis, and embryogenesis in plants is reported and discussed. We propose that, in nucellar cells of apomictic genotypes, PpSERK is the switch that channels embryo sac development and that it may also redirect signaling gene products to compartments other than their typical ones. The involvement of APOSTART in meiosis and programmed cell death is also discussed.

Sexual reproduction of the invasive green alga Caulerpa racemosa var. occidentalis in the Mediterranean Sea

Since the beginning of the 1990s, a pan-tropical species Caulerpa racemosa var. occidentalis has been recorded on the numerous new locations throughout the Mediterranean, specifically on its northwestern part where until then it had never been observed. Such extensive spreading is probably supported by successful sexual reproduction. Field observations of fertile plants and synchronous gamete release of C. racemosa var. occidentalis were carried out in Saronikos Gulf (Greece, Aegean Sea) at the beginning of July 1999. The fertile plants were detected due to reticulate depigmented protoplasmic masses and cylindrical papillae. The alga is monoecious. The both sex gametes were released synchronously from all the fertile plants approximately 14 min before sunrise and formed a green gamete cloud. Although both sex gametes were present, low gamete compatibility was noted during the laboratory examination.