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.

In Vitro Fertilization of Angiosperms-10-Year Effort in China

This review gives a brief retrospect to the development on in vitro fertilization (IVF) of angiosperms in China. During the last decade Chinese scientists put great enthusiasm and efforts on IVF system construction and built up notable contributions to the flourish of this field. Keeping pace with international development and participating international cooperation in the field of IVF, Chinese scientists have now focused on the investigation of basic mechanism relevant to possible gamete interaction, egg cell activation and early embryogenesis by IVF. In vitro manipulation techniques are combined with cytological and molecular biological approaches to unveil the double fertilization mysteries.

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.

Participation of epididymal cysteine-rich secretory proteins in sperm-egg fusion and their potential use for male fertility regulation

Rat protein DE is an androgen-dependent cysteine-rich secretory protein （CRISP） synthesized by proximal epididymal regions. DE, also known as CRISP-1, is localized on the equatorial segment of acrosome-reacted spermatozoa and participates in gamete fusion through binding to egg complementary sites. Immunization of rats with DE inhibits fertility and sperm fusion ability, suggesting that DE represents a good epididymal contraceptive target. Recombinant DE fragments and synthetic peptides revealed that DE binds to the egg via a 12-amino acid region of an evolutionarily conserved motif, Signature 2 （S2）. The ability of other CRISP to bind to the rat egg was correlated with their S2 amino acid sequences. Although testicular protein Tpx- 1 （CRISP-2） was capable of binding to rodent eggs, human epididymal AEG-related protein （ARP） and helothermine （from lizard saliva） were not. The S2 region presented only two substitutions in Tpx-1 and four in ARP and helothermine, compared with the DE S2, suggesting that this amino acid sequence was relevant for egg interaction. Studies with Tpx- 1 and anti-Tpx- 1 revealed the participation of this protein in gamete fusion through binding to complementary sites in the egg. In competition studies, DE reduced binding of Tpx- 1 dose-dependently, indicating that both CRISP share the egg complementary sites. That anti-DE and anti-Tpx-1 inhibit sperm-egg fusion while recognizing only the corresponding proteins, suggests functional cooperation between these homologous CRISP to ensure fertilization success. These results increase our understanding of the molecular mechanisms of gamete fusion and contribute to the development of new and safer fertility regulating methods. （Asian J Androl 2007 July; 9： 528-532）

Effect of temperature and irradiance on the growth and reproduction of Enteromorpha prolifera J.Ag.(Chlorophycophyta,Chlorophyceae)

Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.

Production of aneuhaploid and euhaploid sporocytes by meiotic restitution in fertile hybrids between durum wheat Langdon chromosome substitution lines and Aegilops tauschii

Fertile F1 hybrids were obtained between durum wheat （Triticum durum Desf.） Langdon （LDN） and its 10 disomic substitution （LDN DS） lines with Aegilops tauschii accession AS60 without embryo rescue. Selfed seedset rates for hybrids of LDN with AS60 were 36.87% and 49.45% in 2005 and 2006, respectively. Similar or higher selfed seedset rates were observed in the hybrids of 1D （1A）, 1D （1B）, 3D （3A）, 4D （4B）, 7D （7A）, and 2D （2B） with AS60, while lower in hybrids of 3D （3B） ＋ 3BL, 5D （5A） ＋ 5AL, 5D （5B） ＋ 5B and 6D （6B） ＋ 6BS with AS60 compared with the hybrids of LDN with AS60. Observation of male gametogenesis showed that meiotic restitution, both first-division restitution （FDR） and single-division meiosis （SDM） resulted in the formation of functional unreduced gametes, which in turn produced seeds. Both euhaploid and aneuhaploid gametes were produced in F1 hybrids. This suggested a strategy to simultaneously transfer and locate major genes from the ancestral species T. turgidum or Ae. tauschii. Moreover, there was no significant difference in the aneuhaploid rates between the F1 hybrids of LDN and LDN DS lines with AS60, suggesting that meiotic pairing between the two D chromosomes in the hybrids of LDN DS lines with AS60 did not promote the formation of aneuhaploid gametes.

Analysis of the meiosis in the F_1 hybrids of Longiflorum × Asiatic(LA) of lilies(Lilium) using genomic in situ hybridization

Longiflorum and Asiatic lilies of the genus Lilium of the family Liliaceae are two important groups of modem lily cultivars. One of the main trends of lily breeding is to realize introgression between these groups. With cut style pollination and embryo rescue, distant hybrids between the two groups have been obtained. However, the FI hybrids are highly sterile or some of them could produce a small number of 2n gametes, and their BC1 progenies are usually triploids. Dutch lily breeders have selected many cultivars from these BC1 progenies based on their variation. It is presumably suggested that such variation could be caused by intergenomic recombination and abnormal meiosis during gamete formation in F1 hybrids of Longiflorum × Asiatic （LA） hybrids in Lilium. Therefore, the meiotic process of ten F1 LA hybrids was cytologically investigated using genomic in situ hybridization and traditional cytological methods in the present research. The results showed that： at metaphase I, the homoeologous chromosome pairing among different F1 hybrids ranged from 2.0 to 11.4 bivalents formed by homoeologous chromosomes per pollen mother cell （PMC）, and very few multivalents, and even very few bivalents were formed by two chromosomes within one genome rather than homoeologous chromosomes in some PMCs; at anaphase I, all biva- lents were disjoined and most univalents were divided. Both the disjoined bivalents （half-bivalents） and the divided univalents （sister chromatids） moved to the opposite poles, and then formed two groups of chromosomes; because the two resulting half-bivalents retained their axes in the cell undisturbed, many crossover types, including single crossovers, three strand double crossovers, four strand double crossovers, four strand triple crossovers, and four strand multiple crossovers between the non-sister chromatids in the tetrads of bivalents, were clearly inferred by analyzing the breakpoints on the disjoined bivalents. The present investigation not only explained the reason for sterility of the Fl LA hybrids and the variation of their BCx progenies, but also provided a new method to analyze crossover types in other F1 interspecific hybrids as well.

Diagnostic tools in male infertility--the question of sperm dysfunction

Sperm dysfunction is the single most common cause of infertility, yet what is remarkable is that, there is no drug a man can take or add to his spermatozoa in vitroto improve fertility. One reason for the lack of progress in this area is that our understanding of the cellular and molecular workings of the mature spermatazoon is limited. However, over the last few years there has been considerable progress in our knowledge base and in addressing new methods to diagnose sperm dysfunction. We review the current state of the field and provide insights for further development. We conclude that： （i） there is little to be gained from more studies identifying/categorizing various populations of men using a basic semen assessment, where an effort is required in making sure the analysis is performed in an appropriate high quality way; （ii） technological development is likely to bring the reality of sperm function testing closer to implementation into the clinical pathways. In doing this, these assays must be robust, cheap （or more appropriately termed cost effective）, easy to use and clinically useful; and （iii） clinical necessity, e.g., the need to identify the highest quality spermatozoon for injection is driving basic research forward. This is an exciting time to be an andrologist and, likely, a fruitful one.

Wheat breeding in the hometown of Chinese Spring

The common wheat landrace Chinese Spring(CS) was made famous by the work of Ernie Sears, a great cytogenetist, who developed a number of CS-based aneuploid series that were used to identify individual wheat chromosomes. Based on this, a standard karyotype and nomenclature system was developed for wheat chromosomes that allowed wheat researchers to analyze and manipulate the wheat genome with unprecedented precision and efficiency. Nevertheless, not much is known about the utilization of CS at its hometown, Chengdu in Sichuan province, during early wheat breeding activity. In this review, we follow the speculation that CS is a selection from the Cheng-du-guang-tou(CDGT) landrace. We provide a description of how CDGT became a founder landrace for wheat breeding activities in early times. We show that CDGT-derived varieties were reinforced genetically by crosses to six more exotic parents. These varieties remained the major elite cultivar for several decades. Later, synthetic hexaploid wheats were introduced into the breeding program, firstly using those from CIMMYT and later using materials produced with local tetraploid wheat and goat grass. Finally, we discuss the strategies and future directions to improve wheat yield and resistance through an expanded genetic basis,especially by recapturing lost genetic variations from landraces and related wild species, a process that may set an example for wheat breeders in China and elsewhere.

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.

Intraspecific genetic analysis,gamete release performance,and growth of Sargassum muticum(Fucales,Phaeophyta) from China

Sargassum muticum is one of the most abundant and conspicuous native macroalgae species on the northern coasts of China. It often forms large-scale seaweed beds in subtidal zones. This investigation was designed to understand the intraspecific genetic relationships of this alga based on samples collected from four northern coastal sites of China, and to evaluate gamete release and growth capacity in laboratory conditions. The nuclear internal transcribed spacer 2 （ITS2） sequences of 16 samples from four locations were identical. Based on cox3 gene and partial rbcLS operon sequences, intraspecific genetic variability was detected with three and two ribotypes, respectively. Temperature, not irradiance, was shown to significantly affect gamete release and fertilization. Elevated temperature and irradiance enhanced the growth of germlings and vegetative branchlets. Maximum growth rate of germlings was detected at 18-24℃and an irradiance of 60-100 μmol photons/（m^2.s）. Under ambient conditions （12-25℃ and 60-125 gmol photons/ （m2.s））, relative growth rate of young branchlets could reach 7.5%/d.

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.

Seasonal Dynamics of Male and Female Reproductive Systems in the Siberian Salamander, Salamandrella keyserlingii (Caudata, Hynobiidae)

It is not well known how low temperatures, like a subarctic steppe–tundra climate, influence reproductive traits of ectothermic vertebrates. To begin answering this question, we studied male and female reproductive systems of Salamandrella keyserlingii inhabiting a Tomsk population（southeast of Western Siberia）, Russia, in ecological and physiological terms. In males, before spermiation, the testicular size and weight in late April–early May were greatest of all. Spermiation occurred during breeding immigration in spring when mean air temperature was above 10°С, and at the same time rain fell. After spermiation, the testicular size and weight decreased sharply, and the diameter of the vasa deferentia increased. ＂Spawning＂（i.e., simultaneous extrusion of sperm and oviposition） occurred from late April to late May, and this duration fluctuated in temperature and humidity. The testicular size and weight increased in summer. Sperm mass was detected in the testes by the smear method in April–September, except in June when single fragmented unrealized sperm was detected and in July when spermatids were detected. In females, ovarian weight was greatest in spring before ovulation. From late June, vitellogenesis began in ovarian follicles, in which mint green yolks accumulated. Melanin deposited in the surface of the ovary from July when oviducts were hypertrophying. In contrast, some large-sized females did not show any sexual maturity shortly before hibernation（although these females may be subadults）. These results suggest that low temperatures in Siberia induce early timing of gamete maturation in females, but the females＇ reproductive cycle might also be biennial. A reproductive cycle in males was annual with the completion of the gamete maturation process in August.

Observation of female gamete (Carpogonia) germination of Porphyra yezoensis and P. oligospermatangia

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture of Porphyra. Study on samples of wild and cul- tivated Porphyra yezoensis and P. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells of Porphyra yezoensis had typical features of female gamete (carpogonia) but archeospore. Therefore, the female gametes are responsible in developing leafy thalli.

The environmental adaptability and reproductive properties of invasive green alga Codium fragile from the Nan'ao Island,South China Sea

It has been widely recognized that biological invasion has become one of the greatest threats to the ecosystem.Codium fragile is an invasive species which exhibits a variety of attributes like parthenogenesis,winter fragment,and vegetative reproduction;and therefore,it has become a successful invader,colonizing most subtropical regions.In China’s southeast coastal aquaculture waters,the green algal bloom caused by C.fragile will probably become a serious problem.In order to understand more details about the species,an experiment focused on its reproductive characteristics was conducted using culture established from a sample collected in the aquaculture raft of the Nan’ao Island in the South China Sea.The results showed that there were two types of gametes resembling aplanospores and zoospores respectively,both of which were able to germinate.During the gametes liberation,a long mucilage tube was formed out of the mouth of the gametangium assisting dispersal of gametes away from the parent plant.This tube was adapted not only to its surrounding flowing water environment but also to its parent plant’s outer gelatinous structure.In general,the optimum temperature for gametes release and germination was 15-20℃ and 15℃,respectively,which corresponded to the local offshore marine water.The plant was observed to produce vegetative buds under favourable reproductive conditions which were called propagules.They were capable of developing into filamentous thalli.The results will provide some scientific evidences for revealing the biological mechanism of bloom and control strategies of invasive green algae.

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.

Do Quantity and Quality of Irradiance Influence Migration Behavior Motile Cells of the Green Alga, <i>Ulva fasciata</i>?

Motile cells of the green alga, Ulva fasciata respond to the quantity and quality of irradiance simultaneously. The specific responses of motile cell types (gametes and spores) by irradiance influence migration behavior in coastal water environment. Gametes maximally aggregated at the highest white light intensity (250 μmol&middotm-2·s-1), while spores maximally aggregated in the dark (0 μmol m-2·s-1) of this study. Gametes maximally aggregated in green irradiance over blue, red and dark while spore maximally aggregated in the dark. The results of quantity are spectral responses are likely to be underline the ecological success and physiological strategies in varied irradiance environments includes: 1) gametes respond to specific quantities and spectral irradiance;2) spores respond negatively to quantity and quality of irradiance to enhance the probability of finding substratum;and 3) populations of adults that come from these motile cells behaviors. The specific quantities and spectral qualities of irradiance responses show specific ecological migration that can be attributed to photosynthesis under limiting irradiance in coastal waters for the motile cells of U. fasciata.

Chromosome Elimination in Intergeneric Hybrid of <i>Oryza sativa</i>×<i>Luziola peruviana</i>

Oryza sativa and Luziola peruviana present a diploid chromosome number of 2n = 24 and basic number x = 12, confirmed by means metaphase chromosomes counts in young root tips of these species. Hybrid plants O. sativa × L. peruviana, with 2n = 24 chromosomes are originated from simple crosses and present abnormalities in the meiotic behavior, chromosomal aberrations and cytological alteration. This genetic incompatibility is caused by different factors as absence of pairing and recombination, different spindles arrangements, cytoskeleton instability, apoptosis process and chromosomal elimination, leading to micronuclei formation, unbalanced gametes and sterile pollen grains. The chromosome elimination is established as a dynamic process of stabilization of the genome that occurs during hybridization. It is a common phenomenon among intergeneric crosses and corresponds to cytoplasmic and nuclear bodies that reflect chromosomal aberrations resulting from the combination of two genomes with high genetic distance. The genomic conflict occurs in meiosis, possibly by asynchronism and cell cycle length of the genomes involved, or by time differences in replication between parental species leading to strand breaks and genomic rearrangements.