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Abstract Background Malaria, a global health concern, is caused by parasites of the Plasmodium genus, which undergo gametogenesis in the midgut of mosquitoes after ingestion of an infected blood meal. The resulting male and female gametes fuse to form a zygote, which differentiates into a motile ookinete. After traversing the midgut epithelium, the ookinete differentiates into an oocyst on the basal side of the epithelium. Methods Membrane proteins with increased gene expression levels from the gamete to oocyst stages in P. berghei were investigated utilizing PlasmoDB, the functional genomic database for Plasmodium spp. Based on this analysis, we selected the 184-kDa membrane protein, Pb184, for further study. The expression of Pb184 was further confirmed through immunofluorescence staining, following which we examined whether Pb184 is involved in fertilization using antibodies targeting the C-terminal region of Pb184 and biotin-labeled C-terminal region peptides of Pb184. Results Pb184 is expressed on the surface of male and female gametes. The antibody inhibited zygote and ookinete formation in vitro. When mosquitoes were fed on parasite-infected blood containing the antibody, oocyst formation decreased on the second day after feeding. Synthesized biotin-labeled peptides matching the C-terminal region of Pb184 bound to the female gamete and the residual body of male gametes, and inhibited differentiation into ookinetes in the in vitro culture system. Conclusions These results may be useful for the further studying the fertilization mechanism of Plasmodium protozoa. There is also the potential for their application as future tools to prevent malaria transmission. Graphical Abstract

Harmful algal blooms (HAB) are natural environmental occurrences that can disrupt ecosystem function that supports fisheries and aquaculture, as well as rendering harvested seafood, especially shellfish, unsafe for consumption by humans or wildlife species. Many dinoflagellates that cause HAB have a life cycle with a sexually produced resting stage called the resting cyst. The resting cyst enables the species to persist in an area where conditions for growth vary seasonally. These species often are found as vegetative stages only during a short period of the year. Most of the time is spent dormant or quiescent as thick-walled resting cysts with very low metabolic activity. By summarizing findings from an iterative series of research projects investigating different parts of the sexual life cycle, a more complete picture of the role of the sexual stages emerges, illuminating the consequences of life cycle within the environmental context. Gametes, the sexual stages, are formed at the end of the growing season in response to environmental signals which remain largely unknown. Gametes have lower cell-specific density and different swimming behavior compared to vegetative cells. Specifically, vegetative cells perform daily vertical migrations; whereas, gametes accumulate in patterns influenced by lower cell-specific density, changed swimming behavior, and attraction to each other. The patterns and patches of accumulated gametes (sexually induced cells) aggregate into larger and larger patterns. Together with large-scale hydrographic water movements, such as upwelling, water stratification, and fronts, cells originating from a low vegetative cell density background distribution assemble and become concentrated within a constricted space, thus forming a dense "bloom." This process is distinctly different from the paradigm of blooms resulting from simple, vegetative cell divisions. Undisturbed blooms of cyst-producing dinoflagellate gametes end with gamete fusion into diploid zygotes that transform into resting cysts. The resting cysts sink according to shape and cell-specific density into the silt fraction of the sediment. Cyst preservation depends upon the oxygenation level of the sediment and the presence of fauna. Hypoxic/anoxic conditions lower cyst mortality from benthic grazers. The reestablishment of motile, vegetative cells occurs under seasonally favorable conditions, and successful population growth depends upon environmental conditions, such as weather and nutrient availability. Factors that increase HAB risks of resting cyst-producing dinoflagellates are eutrophication leading to high cell numbers and high cyst preservation in hypoxic benthic zones. Hydrographic factors causing increased cell accumulation also are important, and intensified water stratification can amplify encystment success. These insights underscore mechanisms by which climate change is affecting HAB ecology and subsequent effects upon marine and coastal fisheries and aquaculture. [ABSTRACT FROM AUTHOR]

Abstract HEI10 is a conserved E3 ubiquitin ligase involved in crossover formation during meiosis, and is thus essential for both male and female gamete development. Here, we have discovered a novel allele of HEI10 in rice that produces a truncated HEI10 protein missing its N-terminal RING domain, namely sh1 (shorter hei10 1). Unlike previously reported hei10 null alleles that are completely sterile, sh1 exhibits complete male sterility but retains partial female fertility. The causative sh1 mutation is a 76 kb inversion between OsFYVE4 and HEI10, which breaks the integrity of both genes. Allelic tests and complementation assays revealed that the gamete developmental defects of sh1 were caused by disruption of HEI10. Further studies demonstrated that short HEI10 can correctly localise to the nucleus, where it could interact with other proteins that direct meiosis; expressing short HEI10 in hei10 null lines partially restores female fertility. Our data reveal an intriguing mutant allele of HEI10 with differential effects on male and female fertility, providing a new tool to explore similarities and differences between male and female meiosis.

Rabbits constitute an interesting model to understand gamete interaction and test novel Artificial Reproductive Techniques, but in vitro fertilization (IVF) is particularly problematic in this species. We have conducted a series of experiments to develop a consistent IVF technique. Initially, we checked viability, acrosome integrity, capacitation and motility in ejaculated sperm purified by a density gradient and incubated at different times in three different media: Tyrode's Albumin Lactate Pyruvate (TALP), human tubal fluid (HTF), and Brackett and Oliphant (BO). Total and progressive motility at 10–24 h and linearity from 3 h onwards was significantly higher in BO medium compared to TALP and HTF. Subsequently, cumulus-oocyte complexes (COCs) collected 10 h after induction of ovulation were incubated with sperm in TALP, HTF or BO for 18 h with or without performing sperm pre-incubation for 6 h. Pronuclear formation rate at 18 h was significantly higher in BO compared to other media (∼84 % vs. 17–22 %) and was not improved by pre-incubation. As COCs recovery rate was low at 10 h after induction of ovulation, COCs were collected at 12 h and co-incubated with sperm in BO. Pronuclear formation rate was similar than those obtained in COCs collected at 10 h (∼85 %), and when embryos were allowed to develop in vitro, the protocol yielded high cleavage and blastocyst rates (91 and 59 %, respectively). In conclusion, ejaculated rabbit sperm purified in a density gradient fertilize efficiently COCs collected at 12 h in BO medium. • Motility parameters of rabbit sperm after prolonged incubation were better in BO medium compared to TALP and HTF. • Fertilization rates were significantly higher in BO medium compared to TALP or HTF. • Sperm pre-incubation for 6 h in BO did not improved fertilization rates compared to no pre-incubation. • Rabbit sperm purified by a density gradient fertilize efficiently COCs collected at 10–12 h after ovulation induction. [ABSTRACT FROM AUTHOR]

Coral reefs have been declining worldwide due to multiple threats. Various approaches for coral restoration have been employed to increase coral populations. Sexual propagation is a crucial technique that can enhance the genetic diversity of coral offspring, thereby increasing coral reef resilience in the face of a changing environment. However, the effectiveness of using sexually reared corals for transplantation depends on many factors, including the biological traits of the coral and the physical environment. This study investigated the relationship between Acropora humilis and Symbiodiniaceae during the ontogenetic stages of the coral in ex-situ conditions and after transplantation to a natural reef. Coral sexual propagation techniques were conducted to produce experimental coral colonies. The fertilization rates of coral gametes averaged 98.48 ± 0.34%. However, the survival rate of juvenile corals gradually declined to 45.96 ± 1.31% at 18 months old under hatchery conditions and to 20% after transplantation to a natural reef. Acropora humilis associated with Symbiodiniaceae lineages belonging to three genera: Symbiodinium, Cladocopium, and Durusdinium. Reared juvenile corals developed a more specific and stable association with particular Symbiodiniaceae under hatchery conditions, whereas after transplantation, corals tended to contain a higher diversity of Symbiodiniaceae lineages. These results indicate that a shift in Symbiodiniaceae composition can provide longterm benefits to corals during their ontogenetic cycle and when the environment changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Conserved membrane protein Pbs54 is associated with the plasma membranes of Plasmodium berghei gametes and ookinetes. • Pbs54 deletion results in fertilization defects in both male and female gametes. • Anti-Pbs54 sera inhibit ookinete formation in vitro. The successful completion of gamete fertilization is essential for malaria parasite transmission, and this process can be targeted by intervention strategies. In this study, we identified a conserved gene (PBANKA_0813300) in the rodent malaria parasite Plasmodium berghei , which encodes a protein of 54 kDa (designated as Pbs54). Localization studies indicated that Pbs54 is associated with the plasma membranes of gametes and ookinetes. Functional studies by gene disruption showed that the Δpbs54 parasites had no defect in asexual proliferation, gametocyte development, or gametogenesis. However, the interactions between male and female gametes were significantly decreased compared with wild-type parasites. The Δpbs54 lines did not show a further reduction in zygote and ookinete numbers during in vitro culture, indicating that the defects were probably restricted to gamete fertilization. Consistent with this finding, mosquitoes fed on Δpbs54 -infected mice showed a 30.1% reduction in infection prevalence and a 74.7% reduction in oocyst intensity. Cross-fertilization assay indicated that both male and female gametes were impaired in the Δpbs54 parasites. To evaluate its transmission-blocking potential, we obtained polyclonal antibodies from mice immunized with the recombinant Pbs54 (rPbs54) protein. In vitro assays showed that anti-rPbs54 sera inhibited ookinete formation by 42.7%. Our experiments identified Pbs54 as a fertility factor required for mosquito transmission and a novel candidate for a malaria transmission-blocking vaccine. [ABSTRACT FROM AUTHOR]

HEI10 is a conserved E3 ubiquitin ligase involved in crossover formation during meiosis, and is thus essential for both male and female gamete development. Here, we have discovered a novel allele of HEI10 in rice that produces a truncated HEI10 protein missing its N-terminal RING domain, namely sh1 (shorter hei10 1). Unlike previously reported hei10 null alleles that are completely sterile, sh1 exhibits complete male sterility but retains partial female fertility. The causative sh1 mutation is a 76 kb inversion between OsFYVE4 and HEI10, which breaks the integrity of both genes. Allelic tests and complementation assays revealed that the gamete developmental defects of sh1 were caused by disruption of HEI10. Further studies demonstrated that short HEI10 can correctly localise to the nucleus, where it could interact with other proteins that direct meiosis; expressing short HEI10 in hei10 null lines partially restores female fertility. Our data reveal an intriguing mutant allele of HEI10 with differential effects on male and female fertility, providing a new tool to explore similarities and differences between male and female meiosis. [ABSTRACT FROM AUTHOR]

Fertility preservation techniques, such as cryopreservation of ovarian tissue, embryos, and oocytes, offer hope for future reproduction to individuals facing conditions like cancer or severe haematologic disorders. While the scientific evidence supporting fertility preservation is limited, it shows promise, and there is a growing trend among fertility experts to extend its application to patients with benign conditions that can cause fertility issues, such as endometriosis. Some forms of endometriosis may have a negative impact on fertility, affecting the ovarian reserve, oocyte quality, and the tubo-ovarian interface. Evaluating fertility preservation in endometriosis patients reveals several key considerations. The diverse nature of endometriosis calls for tailored approaches and distinguishing between the disease and treatment effects on ovarian reserve is crucial. Fertility preservation in endometriosis is complex, demanding consideration of disease variability, treatment effects, accurate assessment, and a clear distinction between ovarian reserve and conception ability. A personalised approach is essential for optimal outcomes in this field. [ABSTRACT FROM AUTHOR]

Gamete donation is governed by ethical rules under the aegis of the French Bioethics Act since 1994. This legislation has been recently amended to bring it into line with social expectations. This reform has implications on the potential donors profils and motivations. Welcoming donors under these new conditions is an opportunity to offer them a place and time to reflect on their act of giving and the meaning of it. [ABSTRACT FROM AUTHOR]

This study explains the lineage in embryo donation and the inheritance of born children. This study was conducted with a library, descriptive and analytical design, relying on books of jurisprudence and laws of Shia and other Islamic religions, as well as citing some legal studies. Under Ayatollah Khamenei's original fatwa in 1990, which permitted gamete donation by third parties. This legal approach paved the way for the adoption of the Embryo Donation to Infertile Spouses Act in 2003. The embryos formed from a man's sperm and the ovum of his legitimate wife, with any methods of embryo formation and its transfer to the aforementioned man and woman, have a legitimate lineage and there will be no problem in the inheritance for the baby. However, the embryos formed from the sperm of another man (other than a legal husband) or the egg of another woman (other than a legal wife) regardless of the method (natural or artificial) will not have legitimate lineage, and as a result, donated children are deprived of inheritance. To ensure the financial future of children born through embryo donation, solutions such as an official will or using the life insurance industry can be considered as a temporary solution. However, it is necessary to review the embryo donation law by religious and legislative authorities. [ABSTRACT FROM AUTHOR]

Coral reefs have been declining worldwide due to multiple threats. Various approaches for coral restoration have been employed to increase coral populations. Sexual propagation is a crucial technique that can enhance the genetic diversity of coral offspring, thereby increasing coral reef resilience in the face of a changing environment. However, the effectiveness of using sexually reared corals for transplantation depends on many factors, including the biological traits of the coral and the physical environment. This study investigated the relationship between Acropora humilis and Symbiodiniaceae during the ontogenetic stages of the coral in ex-situ conditions and after transplantation to a natural reef. Coral sexual propagation techniques were conducted to produce experimental coral colonies. The fertilization rates of coral gametes averaged 98.48 ± 0.34%. However, the survival rate of juvenile corals gradually declined to 45.96 ± 1.31% at 18 months old under hatchery conditions and to 20% after transplantation to a natural reef. Acropora humilis associated with Symbiodiniaceae lineages belonging to three genera: Symbiodinium, Cladocopium, and Durusdinium. Reared juvenile corals developed a more specific and stable association with particular Symbiodiniaceae under hatchery conditions, whereas after transplantation, corals tended to contain a higher diversity of Symbiodiniaceae lineages. These results indicate that a shift in Symbiodiniaceae composition can provide long-term benefits to corals during their ontogenetic cycle and when the environment changes.

Abstract Background Tsetse-transmitted African animal trypanosomiasis is recognised as an important disease of ruminant livestock in sub-Saharan Africa, but also affects domestic pigs, with Trypanosoma simiae notable as a virulent suid pathogen that can rapidly cause death. Trypanosoma simiae is widespread in tsetse-infested regions, but its biology has been little studied compared to T. brucei and T. congolense. Methods Trypanosoma simiae procyclics were cultured in vitro and transfected using protocols developed for T. brucei. Genetically modified lines, as well as wild-type trypanosomes, were transmitted through tsetse flies, Glossina pallidipes, to study T. simiae development in the tsetse midgut, proventriculus and proboscis. The development of proventricular trypanosomes was also studied in vitro. Image and mensural data were collected and analysed. Results A PFR1::YFP line successfully completed development in tsetse, but a YFP::HOP1 line failed to progress beyond midgut infection. Analysis of image and mensural data confirmed that the vector developmental cycles of T. simiae and T. congolense are closely similar, but we also found putative sexual stages in T. simiae, as judged by morphological similarity to these stages in T. brucei. Putative meiotic dividers were abundant among T. simiae trypanosomes in the proboscis, characterised by a large posterior nucleus and two anterior kinetoplasts. Putative gametes and other meiotic intermediates were also identified by characteristic morphology. In vitro development of proventricular forms of T. simiae followed the pattern previously observed for T. congolense: long proventricular trypanosomes rapidly attached to the substrate and shortened markedly before commencing cell division. Conclusions To date, T. brucei is the only tsetse-transmitted trypanosome with experimentally proven capability to undergo sexual reproduction, which occurs in the fly salivary glands. By analogy, sexual stages of T. simiae or T. congolense are predicted to occur in the proboscis, where the corresponding portion of the developmental cycle takes place. While no such stages have been observed in T. congolense, for T. simiae putative sexual stages were abundant in the tsetse proboscis. Although our initial attempt to demonstrate expression of a YFP-tagged, meiosis-specific protein was unsuccessful, the future application of transgenic approaches will facilitate the identification of meiotic stages and hybrids in T. simiae. Graphical Abstract

The term 'cloning' refers to the production of genetically identical individuals but has meant different things throughout the history of science: a natural means of reproduction in bacteria, a routine procedure in horticulture, and an ever‐evolving gamut of molecular technologies in vertebrates. Mammalian cloning can be achieved through embryo splitting, somatic cell nuclear transfer, and most recently, by the use of induced pluripotent stem cells. Several emerging biotechnologies also facilitate the propagation of genomes from one generation to the next whilst bypassing the conventional reproductive processes. In this review, we examine the state of the art of available cloning technologies and their progress in species other than humans and rodent models, in order to provide a critical overview of their readiness and relevance for application in endangered animal conservation. [ABSTRACT FROM AUTHOR]

Malaria elimination may never succeed without the implementation of transmission-blocking strategies. The transmission of Plasmodium spp. parasites from the human host to the mosquito vector depends on circulating gametocytes in the peripheral blood of the vertebrate host. Once ingested by the mosquito during blood meals, these sexual forms undergo a series of radical morphological and metabolic changes to survive and progress from the gut to the salivary glands, where they will be waiting to be injected into the vertebrate host. The design of effective transmission-blocking strategies requires a thorough understanding of all the mechanisms that drive the development of gametocytes, gametes, sexual reproduction, and subsequent differentiation within the mosquito. The drastic changes in Plasmodium falciparum shape and function throughout its life cycle rely on the tight regulation of stage-specific gene expression. This review outlines the mechanisms involved in Plasmodium falciparum sexual stage development in both the human and mosquito vector, and zygote to oocyst differentiation. Functional studies unravel mechanisms employed by P. falciparum to orchestrate the expression of stage-specific functional products required to succeed in its complex life cycle, thus providing us with potential targets for developing new therapeutics. These mechanisms are based on studies conducted with various Plasmodium species, including predominantly P. falciparum and the rodent malaria parasites P. berghei. However, the great potential of epigenetics, genomics, transcriptomics, proteomics, and functional genetic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in studies using human malaria parasites and field isolates. [ABSTRACT FROM AUTHOR]

Background: Tsetse-transmitted African animal trypanosomiasis is recognised as an important disease of ruminant livestock in sub-Saharan Africa, but also affects domestic pigs, with Trypanosoma simiae notable as a virulent suid pathogen that can rapidly cause death. Trypanosoma simiae is widespread in tsetse-infested regions, but its biology has been little studied compared to T. brucei and T. congolense. Methods: Trypanosoma simiae procyclics were cultured in vitro and transfected using protocols developed for T. brucei. Genetically modified lines, as well as wild-type trypanosomes, were transmitted through tsetse flies, Glossina pallidipes, to study T. simiae development in the tsetse midgut, proventriculus and proboscis. The development of proventricular trypanosomes was also studied in vitro. Image and mensural data were collected and analysed. Results: A PFR1::YFP line successfully completed development in tsetse, but a YFP::HOP1 line failed to progress beyond midgut infection. Analysis of image and mensural data confirmed that the vector developmental cycles of T. simiae and T. congolense are closely similar, but we also found putative sexual stages in T. simiae, as judged by morphological similarity to these stages in T. brucei. Putative meiotic dividers were abundant among T. simiae trypanosomes in the proboscis, characterised by a large posterior nucleus and two anterior kinetoplasts. Putative gametes and other meiotic intermediates were also identified by characteristic morphology. In vitro development of proventricular forms of T. simiae followed the pattern previously observed for T. congolense: long proventricular trypanosomes rapidly attached to the substrate and shortened markedly before commencing cell division. Conclusions: To date, T. brucei is the only tsetse-transmitted trypanosome with experimentally proven capability to undergo sexual reproduction, which occurs in the fly salivary glands. By analogy, sexual stages of T. simiae or T. congolense are predicted to occur in the proboscis, where the corresponding portion of the developmental cycle takes place. While no such stages have been observed in T. congolense, for T. simiae putative sexual stages were abundant in the tsetse proboscis. Although our initial attempt to demonstrate expression of a YFP-tagged, meiosis-specific protein was unsuccessful, the future application of transgenic approaches will facilitate the identification of meiotic stages and hybrids in T. simiae. [ABSTRACT FROM AUTHOR]

ABSTRACT Sexual reproduction of the malaria parasites is critical for their transmission to a mosquito vector. Several signaling molecules, such as kinases and phosphatases, are known to regulate this process. We previously demonstrated that Plasmodium falciparum (Pf) Ca2+-dependent protein kinase 4 (CDPK4) and serine/arginine-rich protein kinase 1 (SRPK1) are critical for axoneme formation during male gametogenesis, with genetic deletion of either gene causing a complete block in parasite transmission to the mosquito. A comparative phospho-proteome analysis of Pfcdpk4− and RNA-seq analysis of Pfsrpk1− gametocytes showed that these kinases regulate similar biological processes linked to both microtubule (MT) dynamics and cell motility. One of these proteins was a nuclear MT-associated End Binding protein 1 (EB1), which was hypophosphorylated in Pfcdpk4− gametocytes. To study the functional relevance of EB1, we created gene deletion parasites for EB1. We further demonstrate that Pfeb1− parasites like WT NF54 parasites proliferate normally as asexuals and undergo gametocytogenesis and gametogenesis. Strikingly, these parasites suffer a severe defect in nuclear segregation and partitioning of nuclei into emerging microgametes. Further genetic crosses utilizing male- and female-sterile parasites revealed that Pfeb1− parasites only suffer a male fertility defect. Overall, our study reveals an essential function for PfEB1 in male gamete nuclear segregation and suggests a potential therapeutic avenue in the design of transmission-blocking drugs to prevent malaria transmission from humans to mosquito. IMPORTANCE Gametogenesis and subsequent gamete fusion are central to successful transmission of the malaria parasites to a female Anopheles mosquito vector and completion of the sexual phase of the parasite life cycle. Male gametogenesis involves the formation of axonemes inside male gametes from male gametocytes via active cytoskeleton remodeling. The tubulin and tubulin-binding proteins are, thus, attractive anti-malarial drug targets. In the present study, we demonstrate that a microtubule-binding protein PfEB1 is essential for male gamete fertility, specifically for the inheritance of nuclei from activated male gametocytes. Targeting PfEB1 function may provide new avenues into designing interventions to prevent malaria transmission and disease spread.

The PIWI clade of Argonaute proteins is essential for spermatogenesis in all species examined to date. This protein family binds specific classes of small non-coding RNAs known as PIWI-interacting RNAs (piRNAs) which together form piRNA-induced silencing complexes (piRISCs) that are recruited to specific RNA targets through sequence complementarity. These complexes facilitate gene silencing through endonuclease activity and guided recruitment of epigenetic silencing factors. PIWI proteins and piRNAs have been found to play multiple roles in the testis including the maintenance of genomic integrity through transposon silencing and facilitating the turnover of coding RNAs during spermatogenesis. In the present study, we report the first characterization of PIWIL1 in the male domestic cat, a mammalian system predicted to express four PIWI family members. Multiple transcript variants of PIWIL1 were cloned from feline testes cDNA. One isoform shows high homology to PIWIL1 from other mammals, however, the other has characteristics of a "slicer null" isoform, lacking the domain required for endonuclease activity. Expression of PIWIL1 in the male cat appears limited to the testis and correlates with sexual maturity. RNA-immunoprecipitation revealed that feline PIWIL1 binds small RNAs with an average size of 29 nt. Together, these data suggest that the domestic cat has two PIWIL1 isoforms expressed in the mature testis, at least one of which interacts with piRNAs. [ABSTRACT FROM AUTHOR]

Legislation and policies regarding assisted human reproduction (AHR) vary widely across nations and societies. As one of only 5 European countries which currently lacks legislation, Ireland now has a unique opportunity to learn from other jurisdictions and introduce AHR law that is reflective of the ongoing myriad developments in this complex field. Draft legislation, initially published in 2017, was revised in 2022 with strong political commitment to enacting in the same year. This study sought to ascertain the views of fertility patients (service users) to the proposed AHR legislation in its current format, prior to its implementation. A survey questionnaire, previously designed to investigate the attitudes and perceptions of healthcare professionals (HCPs) towards a broad range of issues contained within the draft AHR Bill, was adapted for a patient/service user population. The survey link was distributed via secure email to all patients that had a doctor consult at our fertility clinic in 2020–2021. The survey link was sent to 4420 patients/service users, of whom 1044 (23.6%) responded. A majority had experienced AHR treatment. Service users indicated strong support for AHR regulation and for access to all AHR techniques for all patients, irrespective of relationship or gender status. A majority of respondents disagreed with aspects of the draft bill regarding mandatory counselling, the timing of assignment of parentage in surrogacy, the exclusion of international surrogacy and the exclusion of men from posthumous AHR. Interestingly, the fertility patient cohort were more liberal in their views and opinions regarding AHR than the Irish HCPs previously surveyed. This study demonstrates the views of a large group of AHR patients/service users towards proposed AHR legislation. Many of their views concur with but others differ from those of the drafters of the legislation and from those of healthcare professionals. Consideration of the views of all these groups and a collaborative approach would help ensure that Ireland has AHR legislation that is inclusive and fit for purpose in the 21st century. [ABSTRACT FROM AUTHOR]

Fasting increases lifespan in invertebrates, improves biomarkers of health in vertebrates and is increasingly proposed as a promising route to improve human health. Nevertheless, little is known about how fasted animals use resources upon refeeding, and how such decisions affect putative trade-offs between somatic growth and repair, reproduction and gamete quality. Such fasting-induced trade-offs are based on strong theoretical foundations and have been recently discovered in invertebrates, but the data on vertebrates are lacking. Here, we report that fasted female zebrafish, Danio rerio, increase investment in soma upon refeeding, but it comes at a cost of egg quality. Specifically, an increase in fin regrowth was accompanied by a reduction in 24 h post-fertilization offspring survival. Refed males showed a reduction in sperm velocity and impaired 24 h post-fertilization offspring survival. These findings underscore the necessity of considering the impact on reproduction when assessing evolutionary and biomedical implications of lifespan-extending treatments in females and males and call for careful evaluation of the effects of intermittent fasting on fertilization. [ABSTRACT FROM AUTHOR]

Dinoflagellates constitute one of the most important groups of primary producers and micro-zooplankton on earth, common in both marine and freshwater environments. Despite their prominent position among phytoplankton, they are difficult to grow into dense cultures in the laboratory. This discrepancy between field and laboratory indicates serious limitations caused by the laboratory culturing conditions. A difficult to study but important factor is the constraints of enclosure in a limited volume of water. We conducted an experiment wherein the dinoflagellate Scrippsiella lachrymosa was grown in "flow cells" – 100 cm3 cylindrical cages constructed from plankton net, inserted in larger volumes of growth medium, allowing an exchange of medium without dilution of the culture. Cell numbers far exceeding the normal for culturing of this species and dinoflagellates in general were attained, even though the experiment was terminated before cultures reached stationary phase. A cell number ten times higher than under regular batch culturing was achieved (up to 340,000 cells mL−1). Pattern formation was distinct in cultures when cells were plentiful and water movements caused cell accumulation, not dispersion. High cell density concurrent with access to new growth medium promoted induction of the sexual cell cycle. The results indicate serious limitations to growth set by enclosure in a limited water volume in laboratory experiments; thus, maximum growth rates of dinoflagellates in favourable field conditions may be vastly underestimated. Cell accumulation behavior of dinoflagellates during the sexual life cycle may together with physical transport by larger forces in nature explain sudden bloom occurrences. [ABSTRACT FROM AUTHOR]

Yellowish myotis present a seasonal reproduction, influenced by rainfall distribution, in which the testis mass, germ cell composition, and brown adipose tissue (B.A.T.) mass change along the reproductive stages. In the present study, tissue xenografts were performed in immunodeficient mice to investigate spermatogenesis development in a stable endocrine milieu and the possible androgenic role of B.A.T. In this study, 41 adult male bats were captured in the Santuário do Caraça, Minas Gerais, Brazil. The gonads and B.A.T. were collected, weighed, and grafted under the mice's back skin. Mice biometric and hormonal data were evaluated after grafting, and the testis grafts and mice gonads were fixed for histological and immunohistochemical analyses. As a result, testis grafts from adult bats presented a continuous germ cell development in all reproductive stages, showing round spermatids in all testis tissues. Furthermore, testis fragments in the Rest stage presented elongating spermatids as the most advanced germ cell type in the seminiferous epithelium after 7 months of grafting. These data indicated that yellowish myotis spermatogenesis could be continued (presenting a constant spermatogonial differentiation) in a stable endocrine milieu, as found in mice. In addition, the best spermatogenic development was achieved when testis fragments were transplanted at their lowest activity (Rest stage). Regarding the B.A.T. grafts, the adipose tissue consumption by mice increased seminal vesicle mass and testosterone serum levels. This data proves that B.A.T. is related to testosterone synthesis, which may be critical in stimulating the differentiation of spermatogonia in yellowish myotis.

Abstract Background Sexual stage surface antigens are potential targets of transmission-blocking vaccines (TBVs). The gametocyte and gamete surface antigen P230, a leading TBV candidate, is critical for red blood cell binding during exflagellation and subsequent oocyst development. Here, the genetic diversity of Pvs230 was studied in Plasmodium vivax parasite isolates from the China–Myanmar border (CMB) and central Myanmar. Methods Plasmodium vivax isolates were collected in clinics from malaria-endemic areas of the CMB (143 samples) and Myanmar (23 samples). The interspecies variable part (IVP, nucleotides 1–807) and interspecies conserved part (ICP, 808–2862) of Pvs230 were amplified by PCR and sequenced. Molecular evolution studies were conducted to evaluate the genetic diversity, signature of selection, population differentiation, haplotype network, and population structure of the study parasite populations and publicly available Pvs230 sequences from six global P. vivax populations. Results Limited genetic diversity was observed for the CMB (π = 0.002) and Myanmar (π = 0.001) isolates. Most amino acid substitutions were located in the IVP and cysteine-rich domain of Pvs230. Evidence of positive selection was observed for IVP and purifying selection for ICP. Codon-based tests identified specific codons under natural selection in both IVP and ICP. The fixation index (F ST) showed low genetic differentiation between East and Southeast Asian populations, with F ST ranging from 0.018 to 0.119. The highest F ST value (F ST = 0.503) was detected between the Turkey and Papua New Guinea populations. A total of 92 haplotypes were identified in global isolates, with the major haplotypes 2 and 9 being the most abundant and circulating in East and Southeast Asia populations. Several detected non-synonymous substitutions were mapped in the predicted structure and B-cell epitopes of Pvs230. Conclusions We detected low levels of genetic diversity of Pvs230 in global P. vivax populations. Geographically specific haplotypes were identified for Pvs230. Some mutations are located within a potential B-cell epitope region and need to be considered in future TBV designs. Graphical Abstract

Biomedical and social scientists are increasingly calling the biological sex into question, arguing that sex is a graded spectrum rather than a binary trait. Leading science journals have been adopting this relativist view, thereby opposing fundamental biological facts. While we fully endorse efforts to create a more inclusive environment for gender‐diverse people, this does not require denying biological sex. On the contrary, the rejection of biological sex seems to be based on a lack of knowledge about evolution and it champions species chauvinism, inasmuch as it imposes human identity notions on millions of other species. We argue that the biological definition of the sexes remains central to recognising the diversity of life. Humans with their unique combination of biological sex and gender are different from non‐human animals and plants in this respect. Denying the concept of biological sex, for whatever cause, ultimately erodes scientific progress and may open the flood gates to "alternative truths." [ABSTRACT FROM AUTHOR]

Morels, which belong to the Ascomycete genus Morchella, are highly valued edible fungi treasured by gourmet chefs worldwide. Some species are saprotrophic and others are able to form facultative mycorrhizal-like associations with plant roots without establishing true ectomycorrhizal symbioses. In general, it is considered that the formation of asexual spores, or mitospores, is an important step in the life cycle of morels. However, ultrastructure characterization and physiological attributes of morel mitospores have received little attention. In this contribution, the mitospores of M. sextelata were successfully induced under laboratory conditions and their ultrastructure, occurrence, germination, physiological characteristics and mating type gene structure were studied. Mitospore production was closely related to aeration, nutrition and humidity conditions. The average germination rate of mitospores on different media and under various induction stimuli was very low, with an average of 1/100,000. Based on the ultrastructure characterization, low germination rate, growth rate decline, rapid aging and mating genotyping, it was concluded that the mitospores of M. sextelata had lost their conventional function as conidia and might act more as mate sperm-like (gamete) structures. Thus, this study contributed to a deeper understanding of the life cycle of the economically and ecologically important morel fungal group. [ABSTRACT FROM AUTHOR]

In oocyte cryopreservation programs, vitrification has overthrown conventional slow freezing both in veterinary and human medicine. In animals, its feasibility in field conditions makes it the preferred technique for the safeguard of genetic resources from zoo or wild animals, including threatened felids, for which the domestic cat is an excellent model. However, many cellular injuries, such as cytoskeleton, mitochondria and meiotic spindle alterations, DNA damage, zona pellucida hardening and cumulus cell loss, might occur following vitrification. After warming, although the exact mechanisms are still unclear, degeneration is a frequent outcome for cat vitrified oocytes. For immature (germinal vesicle) gametes, in vitro maturation after warming is a challenge, and cleavage after fertilization barely reaches 15–30%, while for mature (metaphase II) cryopreserved gametes it can get to 30–50%. Anyway, the progression to late embryos stages is often impaired, and improvements are needed. Standard cryopreservation protocol and the use of conventional in vitro culture systems after warming may not be enough for vitrified oocytes to recover and demonstrate their full developmental potential. Physical or chemical factors applied to oocytes undergoing vitrification, as an enrichment to the vitrification step, or to the culture microenvironment, could create more favorable conditions and promote vitrified oocyte survival and development. From the use of three-dimensional culture systems to the regulation of metabolic activities and cellular pathways, this review aims to explore all the possibilities employed so far, including the studies performed by our own lab, and the future perspectives, to present the most effective strategies for cat oocyte vitrification and the best time for their application (i.e., before, during, or after vitrification-warming). • Oocyte cryopreservation in domestic cat as a model for wild endangered felids. • Vitrification is the most used cryopreservation technique for feline oocytes. • Results of vitrification are still suboptimal, especially for immature oocytes. • Review of ameliorative strategies employed so far for cat oocyte vitrification. • Factors applied before, during, or after vitrification-warming. [ABSTRACT FROM AUTHOR]

Objective: Ireland is one of 5 European countries which currently lacks specific legislation on Assisted Human Reproduction (AHR). Draft legislation was introduced in 2017 and revised in 2022 with a view to enacting legislation this year (2022). This study sought to ascertain the views of healthcare professionals to proposed AHR legislation, prior to the implementation of that legislation.Study Design: A survey questionnaire based on all clinically relevant aspects of the Irish draft AHR Bill 2017 was distributed to relevant healthcare professionals using an online platform.Results: Over 200 healthcare personnel indicated strong support for the availability of AHR techniques, access to treatment for all patient populations regardless of relationship or gender status, and appropriate legislation and regulation in the field. Views of respondents are at variance with several proposals surrounding surrogacy, with 84 % favouring a pre-birth order to assign parentage from birth, rather than the proposed birth order 6 weeks after birth. The majority also support legislation around international surrogacy. Contrary to the draft Bill, respondents believe that men, as well as women, should be able to use posthumously any stored gametes or embryos belonging to the deceased partner or the couple. While the majority favour altruistic gamete donation, respondents support more generous compensation for donors, such as compensation for time lost at work.Conclusion: This study has uniquely ascertained the views of healthcare professionals to imminent AHR legislation. It is hoped that the results will help inform the national legislation as it nears completion. Similar studies could help other countries, and policy bodies such as ESHRE to frame good legislation in this extremely specialised and complex field. [ABSTRACT FROM AUTHOR]

ABSTRACT Plasmodium parasites are the etiological agents of malaria, a disease responsible for over half a million deaths annually. Successful completion of the parasite’s life cycle in the vertebrate host and transmission to a mosquito vector is contingent upon the ability of the parasite to evade the host’s defenses. The extracellular stages of the parasite, including gametes and sporozoites, must evade complement attack in both the mammalian host and in the blood ingested by the mosquito vector. Here, we show that Plasmodium falciparum gametes and sporozoites acquire mammalian plasminogen and activate it into the serine protease plasmin to evade complement attack by degrading C3b. Complement-mediated permeabilization of gametes and sporozoites was higher in plasminogen-depleted plasma, suggesting that plasminogen is important for complement evasion. Plasmin also facilitates gamete exflagellation through complement evasion. Furthermore, supplementing serum with plasmin significantly increased parasite infectivity to mosquitoes and lowered the transmission-blocking activity of antibodies to Pfs230, a potent vaccine candidate currently in clinical trials. Finally, we show that human factor H, previously shown to facilitate complement evasion by gametes, also facilitates complement evasion by sporozoites. Plasmin and factor H simultaneously cooperate to enhance complement evasion by gametes and sporozoites. Taken together, our data show that Plasmodium falciparum gametes and sporozoites hijack the mammalian serine protease plasmin to evade complement attack by degrading C3b. Understanding of the mechanisms of complement evasion by the parasite is key to the development of novel effective therapeutics. IMPORTANCE Current approaches to control malaria are complicated by the development of antimalarial-resistant parasites and insecticide-resistant vectors. Vaccines that block transmission to mosquitoes and humans are a plausible alternative to overcome these setbacks. To inform the development of efficacious vaccines, it is imperative to understand how the parasite interacts with the host immune response. In this report, we show that the parasite can co-opt host plasmin, a mammalian fibrinolytic protein to evade host complement attack. Our results highlight a potential mechanism that may reduce efficacy of potent vaccine candidates. Taken together, our results will inform future studies in developing novel antimalarial therapeutics.

Abstract Background The Plasmodium zygote-to-ookinete developmental transition is an essential step for establishing an infection in the mosquito vector, and antigens expressed during this stage are potential targets for transmission-blocking vaccines (TBVs). The secreted ookinete protein 26 (PSOP26) is a newly identified ookinete surface protein. The anti-PSOP26 serum has moderate transmission-blocking activity, indicating the benefit of further investigating this protein as a target for TBVs. Methods The function of psop26 was analyzed by targeted gene disruption. A chimeric PSOP25-PSOP26 protein was expressed in the Escherichia coli system. The PSOP25-PSOP26 fusion protein, along with mixed (PSOP25 + PSOP26) or single proteins (PSOP26 or PSOP25), were used for the immunization of mice. The antibody titers and immunogenicity of individual sera were analyzed by enzyme-linked immunoassay (ELISA), indirect immunofluorescence assay (IFA), and Western blot. The transmission-blocking activity of sera from different immunization schemes was assessed using in vitro and in vivo assays. Results PSOP26 is a surface protein expressed in Plasmodium gametes and ookinetes. The protein is dispensable for asexual blood-stage development, gametogenesis, and zygote formation, but is essential for the zygote-to-ookinete developmental transition. Specifically, both the prevalence of infections and oocyst densities were decreased in mosquitoes fed on psop26-null mutants. Mixtures of individual PSOP25 and PSOP26 fragments (PSOP25 + PSOP26), as well as chimeras (PSOP25-PSOP26), elicited high antibody levels in mice, with no immunological interference. Antisera against the mixed and fusion proteins elicited higher transmission-reducing activity (TRA) than antisera against the single PSOP26 antigen, but comparable to antisera against PSOP25 antigen alone. Conclusions PSOP26 plays a critical role in the zygote-to-ookinete developmental transition. PSOP25 is a promising TBV candidate that could be used alone to target the ookinete stage.

Objective: To describe a unique case of primary ovarian insufficiency and review the systemic barriers in place that hinder reproductive autonomy for Black women who require third-party reproduction. Design: Case report and review of the literature. Setting: Safety-net hospital in an urban community. Patient(s): A 36-year-old Black woman, gravida 0, with primary ovarian insufficiency who desires future fertility but is restricted by systemic barriers. Intervention(s): Chromosome analysis. Main Outcome Measure(s): Not applicable. Result(s): Balanced reciprocal translocation between chromosomes 1 and 13: 46,XX,t(1;13)(q25;q14.1). Conclusion(s): The field of assisted reproductive technology has evolved at an exponential rate, yet it unfortunately benefits some and not all. It is imperative that when we advocate for full spectrum infertility care, that this encompasses everyone. As we continue to further study and develop assisted reproductive technology, we must not forget to consider the factors leading to racial and socioeconomic disparities in reproductive care access, utilization, and outcomes.

Cryptic female choice (CFC) is commonly assumed to act only in polyandrous mating systems, which allows females to bias fertilization towards the sperm of particular males. However, accumulated evidence has demonstrated that sperm show significant phenotypic and genotypic variation also within single ejaculates, which have important consequences for offspring phenotype and fitness. Here, I argue that these neglected sources of intra‐male sperm variation often allow CFC to act also within individual males and facilitate fertilization bias towards genetically compatible (or otherwise preferred) sperm haplotypes. In this article, I explain prerequisites for within‐male CFC, the criteria for demonstrating it and summarize accumulated evidence for this emerging selection process. Then, I evaluate prevalence of within‐male CFC and review its potential evolutionary consequences. The aim of this article is to broaden the current definition of CFC by demonstrating that CFC has potential to act in all mating systems, in both internally and externally fertilizing species. Incorporation of the within‐male CFC concept into the current models of sexual selection may provide novel insights into the deeper understanding of selective factors driving the evolution of mating systems and reproductive proteins. Finally, within‐male CFC towards particular sperm haplotypes may increase our understanding of non‐Mendelian inheritance. [ABSTRACT FROM AUTHOR]

Background: Sexual stage surface antigens are potential targets of transmission-blocking vaccines (TBVs). The gametocyte and gamete surface antigen P230, a leading TBV candidate, is critical for red blood cell binding during exflagellation and subsequent oocyst development. Here, the genetic diversity of Pvs230 was studied in Plasmodium vivax parasite isolates from the China–Myanmar border (CMB) and central Myanmar. Methods: Plasmodium vivax isolates were collected in clinics from malaria-endemic areas of the CMB (143 samples) and Myanmar (23 samples). The interspecies variable part (IVP, nucleotides 1–807) and interspecies conserved part (ICP, 808–2862) of Pvs230 were amplified by PCR and sequenced. Molecular evolution studies were conducted to evaluate the genetic diversity, signature of selection, population differentiation, haplotype network, and population structure of the study parasite populations and publicly available Pvs230 sequences from six global P. vivax populations. Results: Limited genetic diversity was observed for the CMB (π = 0.002) and Myanmar (π = 0.001) isolates. Most amino acid substitutions were located in the IVP and cysteine-rich domain of Pvs230. Evidence of positive selection was observed for IVP and purifying selection for ICP. Codon-based tests identified specific codons under natural selection in both IVP and ICP. The fixation index (FST) showed low genetic differentiation between East and Southeast Asian populations, with FST ranging from 0.018 to 0.119. The highest FST value (FST = 0.503) was detected between the Turkey and Papua New Guinea populations. A total of 92 haplotypes were identified in global isolates, with the major haplotypes 2 and 9 being the most abundant and circulating in East and Southeast Asia populations. Several detected non-synonymous substitutions were mapped in the predicted structure and B-cell epitopes of Pvs230. Conclusions: We detected low levels of genetic diversity of Pvs230 in global P. vivax populations. Geographically specific haplotypes were identified for Pvs230. Some mutations are located within a potential B-cell epitope region and need to be considered in future TBV designs. [ABSTRACT FROM AUTHOR]

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.

Malaria elimination may never succeed without the implementation of transmission-blocking strategies. The transmission of Plasmodium spp. parasites from the human host to the mosquito vector depends on circulating gametocytes in the peripheral blood of the vertebrate host. Once ingested by the mosquito during blood meals, these sexual forms undergo a series of radical morphological and metabolic changes to survive and progress from the gut to the salivary glands, where they will be waiting to be injected into the vertebrate host. The design of effective transmission-blocking strategies requires a thorough understanding of all the mechanisms that drive the development of gametocytes, gametes, sexual reproduction, and subsequent differentiation within the mosquito. The drastic changes in Plasmodium falciparum shape and function throughout its life cycle rely on the tight regulation of stage-specific gene expression. This review outlines the mechanisms involved in Plasmodium falciparum sexual stage development in both the human and mosquito vector, and zygote to oocyst differentiation. Functional studies unravel mechanisms employed by P. falciparum to orchestrate the expression of stage-specific functional products required to succeed in its complex life cycle, thus providing us with potential targets for developing new therapeutics. These mechanisms are based on studies conducted with various Plasmodium species, including predominantly P. falciparum and the rodent malaria parasites P. berghei. However, the great potential of epigenetics, genomics, transcriptomics, proteomics, and functional genetic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in studies using human malaria parasites and field isolates.

The Development Origins of Health and Disease (DOHaD) theory suggests that adverse environmental factors in early life contribute to the development of chronic disease in adulthood. Compared to the intrauterine developmental period of the embryo and fetus, gametes take decades to develop and mature, and are more susceptible to potential damage. Changes in the gametes can be further transmitted to the offspring, leading to an increased risk of congenital anomalies and chronic adult disease in them, and intergenerational transmission effects can exist. Epigenetic modification refers to the regulation of gene expression without altering the nucleotide sequence, and the proposed doctrine offers the possibility of exploring the mechanisms of developmental-derived diseases. This paper summarizes the research progress of the gamete and embryo-fetal origins of diseases, and illustrates the important role of epigenetic mechanisms in this regard, and further emphasizes the importance of health interventions before conception and early in life to shift the primary prevention of diseases to the gametogenesis and intrauterine development of embryos and fetuses.

Concentrative nucleoside transporters (Cnts) are unidirectional carriers that mediate the energy-costly influx of nucleosides driven by the transmembrane sodium gradient. Cnts are transmembrane proteins that share a common structural organization and are found in all phyla. Although there have been studies on Cnts from a biochemical perspective, no deep research has examined their role at the organismal level. Here, we investigated the role of the Drosophila melanogaster cnt1 gene, which is specifically expressed in the testes. We used the CRISPR/Cas9 system to generate a mutation in the cnt1 gene. The cnt1 mutants exhibited defects in the duration of copulation and spermatid maturation, which significantly impaired male fertility. The most striking effect of the cnt1 mutation in spermatid maturation was an abnormal structure of the sperm tail, in which the formation of major and minor mitochondrial derivatives was disrupted. Our results demonstrate the importance of cnt1 in male fertility and suggest that the observed defects in mating behavior and spermatogenesis are due to alterations in nucleoside transport and associated metabolic pathways.

The PIWI clade of Argonaute proteins is essential for spermatogenesis in all species examined to date. This protein family binds specific classes of small non-coding RNAs known as PIWI-interacting RNAs (piRNAs) which together form piRNA-induced silencing complexes (piRISCs) that are recruited to specific RNA targets through sequence complementarity. These complexes facilitate gene silencing through endonuclease activity and guided recruitment of epigenetic silencing factors. PIWI proteins and piRNAs have been found to play multiple roles in the testis including the maintenance of genomic integrity through transposon silencing and facilitating the turnover of coding RNAs during spermatogenesis. In the present study, we report the first characterization of PIWIL1 in the male domestic cat, a mammalian system predicted to express four PIWI family members. Multiple transcript variants of PIWIL1 were cloned from feline testes cDNA. One isoform shows high homology to PIWIL1 from other mammals, however, the other has characteristics of a “slicer null” isoform, lacking the domain required for endonuclease activity. Expression of PIWIL1 in the male cat appears limited to the testis and correlates with sexual maturity. RNA-immunoprecipitation revealed that feline PIWIL1 binds small RNAs with an average size of 29 nt. Together, these data suggest that the domestic cat has two PIWIL1 isoforms expressed in the mature testis, at least one of which interacts with piRNAs.

Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery. [ABSTRACT FROM AUTHOR]

Background: The Plasmodium zygote-to-ookinete developmental transition is an essential step for establishing an infection in the mosquito vector, and antigens expressed during this stage are potential targets for transmission-blocking vaccines (TBVs). The secreted ookinete protein 26 (PSOP26) is a newly identified ookinete surface protein. The anti-PSOP26 serum has moderate transmission-blocking activity, indicating the benefit of further investigating this protein as a target for TBVs. Methods: The function of psop26 was analyzed by targeted gene disruption. A chimeric PSOP25-PSOP26 protein was expressed in the Escherichia coli system. The PSOP25-PSOP26 fusion protein, along with mixed (PSOP25 + PSOP26) or single proteins (PSOP26 or PSOP25), were used for the immunization of mice. The antibody titers and immunogenicity of individual sera were analyzed by enzyme-linked immunoassay (ELISA), indirect immunofluorescence assay (IFA), and Western blot. The transmission-blocking activity of sera from different immunization schemes was assessed using in vitro and in vivo assays. Results: PSOP26 is a surface protein expressed in Plasmodium gametes and ookinetes. The protein is dispensable for asexual blood-stage development, gametogenesis, and zygote formation, but is essential for the zygote-to-ookinete developmental transition. Specifically, both the prevalence of infections and oocyst densities were decreased in mosquitoes fed on psop26-null mutants. Mixtures of individual PSOP25 and PSOP26 fragments (PSOP25 + PSOP26), as well as chimeras (PSOP25-PSOP26), elicited high antibody levels in mice, with no immunological interference. Antisera against the mixed and fusion proteins elicited higher transmission-reducing activity (TRA) than antisera against the single PSOP26 antigen, but comparable to antisera against PSOP25 antigen alone. Conclusions: PSOP26 plays a critical role in the zygote-to-ookinete developmental transition. PSOP25 is a promising TBV candidate that could be used alone to target the ookinete stage. [ABSTRACT FROM AUTHOR]

Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery.

Plasmodium falciparum sexual stage gametocytes are critical for parasite transmission from the human host to the mosquito vector. Mature gametocytes generate fertile male (micro-) or female (macro-) gametes upon activation inside the mosquito midgut. While a number of parasite genes have been described that are critical for P. falciparum gametogenesis and fertility, no parasite gene has been shown to have a unique function in macrogametes. The genome of P. falciparum encodes numerous RNA-binding proteins. We identified a novel protein containing a putative RNA-binding domain, which we named Macrogamete-Contributed Factor Essential for Transmission (MaCFET). This protein is expressed in the asexual and sexual stages. Parasites that carry a deletion of MaCFET (Pfmacfet¯), developed normally as asexual stages, indicating that its function is not essential for the asexual proliferation of the parasite in vitro. Furthermore, Pfmacfet¯ male and female gametocytes developed normally and underwent activation to form microgametes and macrogametes. However, by utilizing genetic crosses, we demonstrate that Pfmacfet¯ parasites suffer a complete female-specific defect in successful fertilization. Therefore, PfMaCFET is a critical female-contributed factor for parasite transmission to the mosquito. Based on its putative RNA-binding properties, PfMaCFET might be in involved in the regulation of mRNAs that encode female-specific functions for fertilization or female-contributed factors needed post fertilization.

One of the human achievements in the treatment mitochondria is mitochondrial transmission. The disease is caused by a defect in the mother's gamete, for this reason, doctors try to put the mother gamete nucleus in the gamete without the donor female nucleus to ensure the future health of the child with the aim of treating and preventing with mitochondrial diseases. Due to the recent emergence of this issue, the problem of child parentage has not been analyzed. Therefore, in this paper, we aim to answer the question whether the birth of such children can be the source of a relative relationship between all three parents. In order to respond to this question, in order to respond to this question, by considering the current farash and the customary reason, the child has considered the assignment of the sperm to the owner of sperm according to medical proofs, the study of the role of cell nucleus in the transfer of genetic characteristics also, in terms of the true cause and the analogy of the jurists, the woman owner of the gamete and the owner of the uterus, the mother of the baby is known.

Fertilization is a key process in all sexually reproducing species, yet the molecular mechanisms that underlie this event remain unclear. To date, only a few proteins have been shown to be essential for sperm-egg binding and fusion in mice, and only some are conserved across vertebrates. One of these conserved, testis-expressed factors is SPACA6, yet its function has not been investigated outside of mammals. Here we show that zebrafish spaca6 encodes for a sperm membrane protein which is essential for fertilization. Zebrafish spaca6 knockout males are sterile. Furthermore, Spaca6-deficient sperm have normal morphology, are motile, and can approach the egg, but fail to bind to the egg and therefore cannot complete fertilization. Interestingly, sperm lacking Spaca6 have decreased levels of another essential and conserved sperm fertility factor, Dcst2, revealing a previously unknown dependence of Dcst2 expression on Spaca6. Together, our results show that zebrafish Spaca6 regulates Dcst2 levels and is required for binding between the sperm membrane and the oolemma. This is in contrast to murine sperm lacking SPACA6, which was reported to be able to bind but unable to fuse with oocytes. These findings demonstrate that Spaca6 is essential for zebrafish fertilization and is a conserved sperm factor in vertebrate reproduction.

One of the major cell fate transitions in eukaryotes is entry into meiosis. While in single-celled yeast this decision is triggered by nutrient starvation, in multicellular eukaryotes, such as plants, it is under developmental control. In contrast to animals, plants have only a short germline and instruct cells to become meiocytes in reproductive organs late in development. This situation argues for a fundamentally different mechanism of how plants recruit meiocytes, and consistently, none of the regulators known to control meiotic entry in yeast and animals are present in plants. In recent years, several factors involved in meiotic entry have been identified, especially in the model plant Arabidopsis, and pieces of a regulatory network of germline control in plants are emerging. However, the corresponding studies also show that the mechanisms of meiotic entry control are diversified in flowering plants, calling for further analyses in different plant species. [ABSTRACT FROM AUTHOR]

One previously unstudied aspect of differences between sexual and asexual life stages in large‐scale transport and accumulation is density (mass per unit volume) of cells in each life stage. The specific density was determined for Scrippsiella lachrymosa cells in medium with and without nitrogen (N) enrichment through density‐gradient centrifugation. Growth medium without N addition is often called "encystment medium" when used for the purpose of resting cyst formation in cyst‐forming dinoflagellates; mating gametes are usually seen after 2–3 days. Significant differences in specific density were found after 2 days in encystment medium simultaneously with the observation of typical gamete swimming behavior and mating. The specific density of cells in encystment medium was 1.06 g · cm−3; whereas, the specific density of cells in growth medium was 1.11 g · cm−3. Cells in encystment medium were found to have significantly increased lipid content, reduced chlorophyll content, and reduced internal complexity. The findings may explain differential transport of less dense and chemotactically aggregating gametes into surface blooms in contrast to denser vegetative cells that perform daily vertical migration and do not aggregate. Passive accumulation of non‐migrating gametes into layers in stagnant water also can be explained, as well as sinking of zygotes when the storage of highly dense starch increases. Resting cysts had a density of over 1.14 g · cm−3 and would sink to become part of the silt fraction of the sediment. We suggest that differences in behavior and buoyancy between sexual and asexual life stages cause differences in cell accumulation, and therefore large‐scale, environmental transport could be directly dependent upon life‐cycle transitions. [ABSTRACT FROM AUTHOR]

Abstract Background Traditional selection in livestock and crops focuses on additive genetic values or breeding values of the individuals. While traditional selection utilizes variation between individuals, differences between gametes within individuals have been less frequently exploited in selection programs. With the successful implementation of genomic selection in livestock and crops, estimation and selection for gametic variation is becoming possible. Results The gamevar.f90 software is designed to estimate individual-level variance of genetic values of gametes for complex traits in large populations. The software estimates the (co)variances of gametic diversity as well as other diversity parameters that are useful for selection programs and mating designs. The calculation is carried out chromosome by chromosome and can be easily parallelized. The gamevar.f90 program is written in Fortran with efficient computing algorithms in a user-friendly software package with easily-handled input and output files. Finally, we applied the program to estimate gametic variance for hundreds of bulls for lifetime net merit, productive life, and livability. The RPTA (relative predicted transmitting ability), assuming a future selection intensity (i f ) of 1.5, showed larger variance than GEBV/2, indicating that greater future genetic gains can be obtained using an index that includes gametic variances. We also used the relative coefficient of variation to estimate with 95% confidence the sample sizes required to observe 90% variability of the progeny for lifetime net merit (or to allow at maximum 10% of change in the EBV predicted from progeny data). Conclusions Collectively, we develop an efficient computer program package, gamevar.f90, for estimating gametic variance for large numbers of individuals. The novel information on gametic variation will be useful in future animal and crop breeding programs.