Reproductive Biology Research Articles

Unveiling the embryo structure in Bromeliaceae Juss. (Poales): morphological diversity, anatomy, and character evolution.

Recent studies have documented numerous morphoanatomical variations for the seed coat in Bromeliaceae. However, the structural diversity and character evolution of the embryo within this family remain largely unexplored. Given the embryo's significance in plant diversification, this research aims to investigate the morphology and key anatomical features of Bromeliaceae embryos, providing insights into character evolution, taxonomic applications, and reproductive biology. We analysed samples of 88 species from 50 genera representing the major lineages of Bromeliaceae, using standard plant microtechniques adapted for seeds. To determine ancestral traits, parsimony and maximum likelihood analyses were performed in a consensus supertree combining previous phylogenies. This study identified 14 informative characters, highlighting significant differences among groups, particularly in embryo morphology, differentiation, and anatomical traits. Our analysis revealed that undifferentiated embryos with a vestigial cotyledonary hyperphyll are plesiomorphic in Bromeliaceae. They have evolved multiple times into rudimentary or well-differentiated embryos, the latter exhibiting intermediate or large sizes and diverse cotyledonary hyperphyll morphologies. The cotyledonary hypophyll varies in sheath lobes and slit morphologies, and is curved or expanded exclusively in Bromelioideae representatives. Similarly, several patterns of hypocotyl/radicle constriction are unique to Tillandsioideae and plesiomorphic for this clade. Although rudimentary embryos exhibit simpler and more uniform anatomy, they are distinct from undifferentiated embryos, which lack defined organs and internal tissues. In contrast, well-differentiated embryos possess more complex anatomical structures, including a multi-layered shoot apical meristem and root cap, a broad cotyledonary sheath, and often leaf primordia, the latter evolving independently several times only in large embryos. Our findings reveal a previously unknown morphological diversity for embryos in Bromeliaceae, enhancing our understanding of the morphological evolution of its major lineages. In addition, it introduces new informative characters for the family's systematics and broadens our understanding of the reproductive biology of Bromeliaceae.

Maternal lipid mobilization is essential for embryonic development in the malaria vector Anopheles gambiae.

Lipid metabolism is an essential component in reproductive physiology. While lipid mobilization has been implicated in the growth of Plasmodium falciparum malaria parasites in their Anopheles vectors, the role of this process in the reproductive biology of these mosquitoes remains elusive. Here, we show that impairing lipolysis in Anopheles gambiae, the major malaria vectors, leads to embryonic lethality. Embryos derived from females in which we silenced the triglyceride lipase AgTL2 or the lipid storage droplet AgLSD1 develop normally during early embryogenesis but fail to hatch due to severely impaired metabolism. Embryonic lethality is efficiently recapitulated by exposing adult females to broad-spectrum lipase inhibitors prior to blood feeding, unveiling lipolysis as a potential target for inducing mosquito sterility. Our findings provide mechanistic insights into the importance of maternal lipid mobilization in embryonic health that may inform studies on human reproduction.

Microsporogenesis, viability and pollen morphology of five species of Vochysiaceae A.St.-Hil. from a midwestern Brazilian savannah

Despite the growing interest in investigating the reproductive biology of Vochysiaceae A.St.-Hil., more in-depth descriptions of the floral details of its group are needed. Within this context, the present study was conducted to evaluate the stages of microsporogenesis, viability and pollen morphology of the Vochysiaceae species found in a fragment of the Cerrado in the state of Mato Grosso, Brazil. For this purpose, flower buds were collected and prepared for meiotic analysis, acetolysis and scanning electron microscopy. In all analyzed species (Qualea grandiflora Mart., Qualea multiflora Mart., Qualea parviflora Mart., Vochysia cinnamomea Pohl and Vochysia divergens Pohl), meiosis was regular, with a meiotic index greater than 90%, correlating with a high pollen viability rate (greater than 70%). The pollen grains of the five species showed similarities in terms of dispersion, symmetry, polarity and apertural pattern and varied in size between small and medium, oblate-spheroidal and prolate shapes. Based on the multivariate multidimensional scaling analysis, when including quantitative and categorical variables of pollen morphology, the species were able to be satisfactorily differentiated. This approach for the species of Vochysiaceae in the Brazilian savannah (Cerrado) is novel, provides an important source of data for future research on the distribution and evolution of this family, and can be used to foster discussions regarding the delimitation of priority areas for conservation.

Reproductive performance of Channa striata in wetland ecosystems: a fuzzy logic approach to water quality and eco-climatic factors for long-term sustainable management and aquaculture advancement.

The striped snakehead, Channa striata, is commercially and nutritionally important due to its medicinal properties, such as wound healing and antimicrobial abilities. This study investigated the reproductive biology of C. striata in relation to hydro-climatic changes using a fuzzy logic approach for long-term management in the wetland ecosystem (Gajner beel), Bangladesh. A total of 1200 C. striata individuals were collected monthly during January to December 2019 using various fishing methods. Measurements of total length (TL), body weight (BW), and gonad weight (GW) were taken with a precision of 0.01cm and 0.01g, respectively. The GSI (gonadosomatic index in %), MGSI (modified gonadosomatic index in %), and DI (Dobriyal index) were used to determine size at sexual maturity (Lm) and the spawning season. Results revealed a wide range of TL, ranging from 12.7 to 46cm. The Lm was estimated between 21.7 and 25.33cm based on various model as TL vs. GSI, MGSI, and DI; TL-fork length (FL) regressions; and maximum length (Lmax) for this species. The spawning period was observed from April to July, peaking in May, indicated by higher GSI, MGSI, and DI values. Eco-climatic factors showed a significant relationship with GSI, except for total dissolved solids (TDS). Rising temperatures and declining rainfall could delay spawning of C. striata. A fuzzy logic approach was employed to predict future GSI changes over extended periods (e.g., 50 or 60years), enabling anticipation of shifts in the timing and duration of the spawning season. Finally, the findings of our research might be effective to carry out specific conservation efforts of C. striata in response to climate variability in sub-tropical water.

Germination Strategies and Seed Quality of Colobanthus quitensis: Implications for Sustainable Antarctic Ecosystems and Ex Situ Plant Conservation

The conservation of the Antarctic ecosystem is linked to scientific and tourism activities. The Colección Activa de Plantas Vasculares Antárticas at the Universidad de Concepción aims to help conserve the region’s vascular flora to support scientific research while minimizing anthropogenic pressure on natural ecosystems. Colobanthus quitensis is the only native dicotyledonous plant native to Antarctica and, as an extremophilic plant, is capable of withstanding extreme abiotic conditions. This species has potentially important use as a biological model to study the physiological deterioration of dormant seeds and other traits, some of which may contribute to vegetation development in Antarctica. Although studies have addressed the reproduction and germination of C. quitensis, there is no recent synthesis of information regarding its reproductive biology and seed traits that could support its conservation. This work synthesizes and critically analyzes the current knowledge of C. quitensis reproduction in natural and controlled environments, identifying factors that contribute to the decline in seed quality. We propose that growth conditions, seed morphology, and interactions with endophytic fungi influence germination and seedling establishment. We also highlight critical knowledge gaps that must be addressed to better understand the species’ phenology, the impact of biotic and abiotic factors on its development, strategies for seed conservation, and biotechnological applications.

Natural history of cyclical parthenogenesis of aphids (Homoptera: Aphidinea)

The article puts forward and argues the hypothesis of the emergence of cyclical parthenogenesis in aphids as a consequence of their ancestral habitation in closed strobiloid galls on coniferous trees. The period of gall opening is greatly extended in time, which prevents normal panmixia in the population and creates a selective advantage for parthenogenetic reproduction. Migration of aphids to secondary host plants, on which closed galls never form, parthenogenetic reproduction on these plants, and the subsequent simultaneous return of “remigrants” to the main host plant make it possible to synchronize the development of the bisexual generation and achieve mass panmixia only at the end of the life cycle, which coincides with the end of summer growth shoots or the autumn end of the vegetation period as a whole. Due to the fact that the development of the bisexual generation always necessarily occurs in the second half of the year, when the conditions for aphid feeding on arboreal plants become unfavorable, small size of sexual individuals and their reduced fertility (often only one egg per female), in comparison with parthenogenetic generations of the first half of the year, are understandable. The evolutionary transition of aphids from conifers to angiosperms in the Cretaceous period in parallel meant the possibility of development in more spacious galls accommodating several consecutive parthenogenetic generations, the transition to viviparity and telescopic embryonization, significantly accelerating the change of generations. The loss of ovipositor in Phylloxeridae and in hypothetically descended from them Aphidoidea can be explained by the initial life in galls, where egg laying does not require specialized ovipository organs. The evolutionary transition from oviparity of parthenogenetic generations to viviparity probably occurred in the ancestors of modern Eriosomatidae, as evidenced by the plesiomorphic features of the reproductive biology of the latter.

Biological traits and population dynamics for sustainable harvesting of Carcinus maenas

Research focusing on the biological patterns and population dynamics of Carcinus maenas has not been conducted for the purpose of fishery management along the European coastal systems. This has led to the implementation of fisheries management policies without scientific considerations, adversely affecting fishery profitability. To addrees this gap, we studied the crab species’ population dynamics, reproductive biology, and growth patterns across different Portuguese lagoons and estuaries on a monthly basis from 2019 to 2021. Surveys were performed in the Southern (Ria Formosa lagoon and Ria Alvor estuary), Central (Sado river/estuary) and Northern regions (Ria Aveiro estuary) of Portugal. Monthly biological data was used to analyse size-frequency distributions, sex ratios, spawning seasons, recruitment pulses, estimate carapace width at first maturaty and biological growth parameters. It was observed that spawning occurs almost year-round in all systems, with a peak in the colder months, between September and March. In the southern regions of the Portuguese coast, the spawning period starts earlier than in the central and northern systems, with a higher sex ratio recorded for females in all systems. The carapace width at which 50 % (CW50) of individuals reach maturity is similar for both sexes, around 30 mm, a value below to the minimum landing size enforced in Portugal. The analysis of von Bertalanffy growth curves revealed a continuous recruitment with a peak during the colder months, with individuals reaching the size at maturation after six months. The fast growth and continuous recruitment leds to the existence of between four and six growth cohorts for both sexes across all system. The findings of this study can contribute to more effective fisheries management policies for C. maenas in Portugal, such as a reduction of the minimum landing size.

Potential radiosensitive germline biomarkers in the testes of wild mice after the Fukushima accident

We investigated potential germline‐specific radiosensitive biomarkers in the testes of large Japanese field mice (Apodemus speciosus) exposed to low‐dose‐rate (LDR) radiation after the Fukushima accident. Fukushima wild mice testes were analysed via RNA‐sequencing to identify genes differentially expressed in the breeding and non‐breeding seasons when compared to controls. Results revealed significant changes during the breeding season, with Lsp1 showing a considerable upregulation, while Ptprk and Tspear exhibited significant reductions. Conversely, in the non‐breeding season, Fmo2 and Fmo2 (highly similar) were significantly upregulated in radiation‐exposed Fukushima mice. qPCR analysis results were consistent with transcriptome sequencing, detecting Lsp1 and Ptprk regulation in the testes of Fukushima mice. While differences in gene expression were observed, these do not imply any causal association between the identified biomarkers and chronic LDR exposure, as other factors such as the environment and developmental age may contribute. This study provides valuable insights into the reproductive biology is affected by environmental radiation and highlights the value of assessing the effects of chronic LDR radiation exposure on testicular health in wild mice.

Population-based genetic carrier screening. A consensus statement from the Spanish societies: AEGH, AEDP, ASEBIR, SEAGEN, SEF and SEGCD.

Autosomal recessive or X-linked disorders are passed from parents to offspring through Mendelian inheritance patterns and may lead to severe clinical manifestations in early childhood development. Together, the Spanish Association of Human Genetics (AEGH), Association for the Study of Reproductive Biology (ASEBIR), Spanish Association of Genetic Counselling (SEAGEN), Spanish Fertility Society (SEF), Spanish Society of Clinical Genetics and Dysmorphology (SEGCD), and the Spanish Association of Prenatal Diagnostics (AEDP) developed a consensus statement for population-based genetic carrier screening (GCS). The presented opinion statement recommends that preconception GCS services be included in the public healthcare system to support couples' reproductive autonomy and timely medical decision-making. Program design and implementation strategies, as well as key technical, ethical, and legal considerations are discussed.

Inclusion of genital, sexual, and gender diversity in human reproductive teaching: impact on student experience and recommendations for tertiary educators.

Western societal norms have long been constrained by binary and exclusionary perspectives on matters such as infertility, contraception, sexual health, sexuality, and gender. These viewpoints have shaped research and knowledge frameworks for decades and led to an inaccurate and incomplete reproductive biology curriculum. To combat these deficiencies in reproductive systems-related education, our teaching team undertook a gradual transformation of unit content from 2018 to 2023, aiming to better reflect real diversity in human reproductive biology. This initiative involved intentional modifications, including clear use of pronoun self-identification by staff. We addressed the historical lack of representation of genital variation and helped students interrogate oversimplified reproductive biology binaries. A novel assignment was also introduced, prompting students to apply reproductive physiology knowledge to propose innovative assisted reproductive technology solutions for diverse demographics. The collective impact of these innovations had a positive effect on student learning. With improved lecture content and inclusive language, the proportion of inclusive group assignment topics chosen by students more than doubled in 2021. By 2022, coinciding with assessment topic changes, the percentage of inclusive assignments topics surpassed 50%. Further development of laboratory activities on intersex genital variation and genital modification raised further understanding of genital, sexual, gender, and cultural diversity. While implementing these changes posed challenges, pushing both staff and students out of their comfort zones at times, collaboration with relevant organizations and individuals with lived experience of queer identity proved integral. Ultimately, these relatively simple adjustments had a substantial impact on student experiences and appreciation for diversity.NEW & NOTEWORTHY We outline the teaching innovations that we have implemented to improve inclusion of diversity in reproductive biology and physiology contexts. This includes improved representation of genital, sexual, and gender diversity considerations in the curriculum. There is a critical need for these innovations as how we teach fundamentally shapes the understanding of our future medical and health professionals and researchers and thus influences the quality of future medical care and research.

Characterization of sperm morphology in two species of Neotropical bats: Artibeus planirostris and Sturnira erythromos (Phyllostomidae, Chiroptera).

Sperm morphology is considered the best indicator of male fertility. In Neotropical bats, important aspects of sperm morphology have been scantly studied. The aim of the present study was to characterize and compare the sperm morphology and morphometry of Artibeus planirostris and Sturnira erythromos. A total of 11 specimens were analyzed from the Colección de Mamíferos Lillo: five A. planirostris and six S. erythromos. The fixed epididymis were extracted and macerated in Farmer's solution, followed by the routine cytological procedure with different stains. To carry out the description and morphometric analysis, microphotographs were taken under an optical, epifluorescence and scanning electron microscope. A total of 50 sperm from each individual were measured for morphometric analysis. The percentage of normal/abnormal spermatozoa was estimated and the sperm abnormalities were classified. Both species showed morphologically simple spermatozoa with a spatulate head, a short neck, a helical midpiece and a tail that tapers at the final end, similar to other species of Phyllostomidae. The differences observed were: apex of the head was conical in A. planirostris and was oval in S. erythromos; longer head and midpiece in S. erythomos and longer sperm in A. planirostris. Both species showed a high percentage of sperm with normal appearance: 65% for A. planirostris and 72% for S. erythromos. The main sperm abnormalities were: scattered tails and heads, coiled tails, folded midpieces and presence of cytoplasmic droplets. The present work will improve the understanding of their reproductive biology. RESEARCH HIGHLIGHTS: Morphological descriptions and morphometric analyses of the sperm of Artibeus planirostris and Sturnira erythromos were carried out with optical, epifluorescence and scanning electron microscopy.

Reproductive mechanisms, pathologies, and health inclusivity: insights from the 2023 Annual Meeting of the Society for Reproductive Biology.

In 2023, the Society for Reproductive Biology met in Brisbane to deliver its largest scientific program to date. Herein, we detail key areas of notable discovery across the reproductive biology and fertility landscapes, as well as pressing areas that require further research. Specifically, we focus on five key themes: the cellular basis of reproduction; environmental impacts on reproduction; inclusivity in reproductive health; reproductive cancers; and evolution of reproduction mechanisms. Highlights included the utility of organism models, such as using fruit flies to model human genetic disease, and the development of new blastocyst models; the impact of elevated temperature and endocrine-disrupting chemicals on the germline, sex organ development, and fertility in mammals; how we can improve the inclusivity of transgender and Pacific Rainbow+ people in reproductive health; novel insights in reproductive cancer pathogenesis and inhibitor treatments; and the evolution of the sex chromosomes and sex determination across animals. The breadth of topics covered underscores the far-reaching impacts of reproduction and its related processes across life, health, and wellbeing, as well as for food production and the economy.

Evidence of brood parasitism in the sea anemone Aulactinia stella

ABSTRACT Monitoring of the sea anemone Aulactinia stella over several weeks provided evidence of interindividual reciprocal tentacle contacts. Closer examination of images revealed instances where a tentacle either hovered over or entered the mouth of a conspecific and remained there for minutes to hours. These observations align with previous data on reproductive and offspring biology in the same species to suggest deliberate transfer of larvae and/or juveniles across individuals, which would explain how genetically different offspring can be found in brooding females according to the literature. This unique interaction between conspecific sea anemones shows striking similarities with the intraspecific brood parasitism tactics described in insects and birds.

ETUDE DES MARQUEURS BIOCHIMIQUES DU LIQUIDE SEMINAL DANS LE DIAGNOSTIC DIFFERENTIEL DE LAZOOSPERMIE SECRETOIRE ET EXCRETOIRE A LINSP DE BAMAKO (MALI)

Infertility remains a major public health problem in Africa, particularly in Mali, as the main purpose of marriage is procreation. The birth of a child in the home is a source of joy and contributes to the maintenance of the household. The woman is almost always to blame for the couples infertility, as men confuse infertility with virility. The male cause is often discovered during an infertility work-up.The aim of the present study was to measure some biochemical markers of seminal fluid (alphaglucosidase and fructose) in the differential diagnosis of secretory and excretory azoospermia.This was a cross-sectional study, which ran from January 2020 to December 2023. It was carried out in the cytogenetics and reproductive biology department of the INSP, Bamako (Mali). It involved 49 patients selected from 125 confirmed azoospermic patients. Seminal fluid fructose and alphaglucosidase assays were performed on an ELx808, version 2021.Data analysis found that the mean age of patients was 37.5 ± 7.2 years, with a median of 37 years and 75% percentiles (Q3 quartiles) less than or equal to 42 years. Primary infertility was observed in 67.3%, compared with 32.7% for secondary infertility. Monogamy was the most common with 75.5%. The most common lifestyle habits were smoking (28.6%) and exposure of the genitals to heat (12.2%). There was no statistically significant difference (p>0.05) between medical history of varicocele, epididymitis, bilharziosis, mumps, orchitis and cryptorchidism and fructose. For the same medical history, only orchitis is associated with a pathological alphaglucosidase value, with a statistically significant difference (p=0.001). This result remains significant with the Bonferroni correction (0.004).The results of seminal fluid biochemical marker assays (alphaglucosidase and fructose) in our 49 patients showed secretory azoospermia in 32 patients (65.3%) and excretory azoospermia in 17 patients (34.7%). Fructose and hypospermia were not associated with the type of azoospermia (p>0.05). The significance of the association with abnormal alphaglucosidase defined the type of excretory azoospermia (P=0.000000001).Indeed, seminal fluid biochemical marker assays should be requested in all cases of male infertility. These results could provide vital information on all the organs of the male genital tract, enabling practitioners to better manage male infertility.

Genomic correlates of vascular plant reproductive complexity and the uniqueness of angiosperms.

Whole genome duplication (WGD) likely plays an important role in plant macroevolution, and has been implicated in diversification rate shifts, structural innovations, and increased disparity. But the general effects of WGD are challenging to evaluate, in part due to the difficulty of directly comparing morphological patterns across disparate clades. We explored relationships between WGD and the evolution of reproductive complexity across vascular plants using a metric based on the number of reproductive part types. We used multiple regression models to evaluate the relative importance of inferred WGD events, genome size, and a suite of additional variables relating to growth habit and reproductive biology in explaining part type complexity. WGD was a consistent predictor of reproductive complexity only among angiosperms. Across vascular plants generally, reproductive biology, clade identity, and the presence of bisexual strobili (those that produce microsporangiate and megasporangiate organs) were better predictors of complexity. Angiosperms are unique among vascular plants in combining frequent polyploidy with high-reproductive complexity. Whether WGD is mechanistically linked to floral complexity is unclear, but we suggest widespread polyploidy and increased complexity were ultimately facilitated by the evolution of herbaceous growth habits in early angiosperms.

Feeding Aspects and Reproductive Biology of Smalltooth Emperor, Lethrinus microdon (Valenciennes, 1830) in the Gulf of Mannar along the Indian Southeast Coast

Background: The Gulf of Mannar, situated on the southeast coast of India, is a unique distinctive productive marine ecosystem and is rich in biodiversity. Its significance stems from the presence of a string of 21 islands spanning 140 km between Rameswaram and Tuticorin, each adorned with a wealth of coral reefs and hosting a variety of ornamental and marine fish species despite their small and uninhabited nature. It is also first Marine Biosphere Reserve in South and South-East Asia, covers approximately an area of 19,000 sq. km. Methods: Fish samples were collected monthly from three major fishing harbours situated in the Gulf of Mannar along the southeast Coast: Thoothukudi Fishing Harbour, Pamban Fishing Harbour and Chinnamuttom Fishing Harbour from December 2022 to November 2023. These species are caught using trawl net, gill net and hook and line and collected specimens were identified using FAO sheets and standard literature. Result: In this study, a total of 405 specimens were collected. The length weight relationship was estimated for male: W = 0.0522.57, r2 = 0.94, female; W = 0.0572.51, r2 = 0.94; and pooled; W = 0.0632.54, r2 = 0.90, respectively. Fulton condition factor (KF) value for male: 1.22, female: 1.33; and pooled: 1.19, respectively. Gonadosomatic index (GSI) of L. microdon was ranged between 1.21-2.21 for male and 1.85-2.31 for female and Gastrosomatic index (GaSI) varied from 1.45-2.37 for male whereas 1.89-4.43 was found for female. Hepatosomatic index (HSI) of L. microdon was ranged between 0.45-2.54 for male while for female was ranged between 1.11-3.21. The male and female (M:F) sex ratio was estimated 1:0.67. The peak spawning season was observed in June to August. The results provide the baseline biology information required to evaluate the fisheries and sustainable management of these underexploited fishes in the Gulf of Mannar ecosystem.

Transcription factor-dependent regulatory networks of sexual reproduction in Fusarium graminearum.

Transcription factors (TFs) involved in sexual reproduction in filamentous fungi have been characterized. However, we have little understanding of how these TFs synergize within regulatory networks resulting in sexual development. We investigated 13 TFs in Fusarium graminearum, whose knockouts exhibited abortive or arrested phenotypes during sexual development to elucidate the transcriptional regulatory cascade underlying the development of the sexual fruiting bodies. A Bayesian network of the TFs was inferred based on transcriptomic data from key stages of sexual development. We evaluated in silico knockout impacts to the networks of the developmental phenotypes among the TFs and guided knockout transcriptomics experiments to properly assess regulatory roles of genes with same developmental phenotypes. Additional transcriptome data were collected for the TF knockouts guided by the stage at which their phenotypes appeared and by the cognate in silico prediction. Global TF networks revealed that TFs within the mating-type locus (MAT genes) trigger a transcriptional cascade involving TFs that affected early stages of sexual development. Notably, PNA1, whose knockout mutants produced exceptionally small protoperithecia, was shown to be an upstream activator for MAT genes and several TFs essential for ascospore production. In addition, knockout mutants of SUB1 produced excessive numbers of protoperithecia, wherein MAT genes and pheromone-related genes exhibited dysregulated expression. We conclude that PNA1 and SUB1 play central and suppressive roles in initiating sexual reproduction, respectively. This comprehensive investigation contributes to our understanding of the transcriptional framework governing the multicellular body plan during sexual reproduction in F. graminearum.IMPORTANCEUnderstanding transcriptional regulation of sexual development is crucial to the elucidation of the complex reproductive biology in Fusarium graminearum. We performed gene knockouts on 13 transcription factors (TFs), demonstrating knockout phenotypes affecting distinct stages of sexual development. Using transcriptomic data across stages of sexual development, we inferred a Bayesian network of these TFs that guided experiments to assess the robustness of gene interactions using a systems biology approach. We discovered that the mating-type locus (MAT genes) initiates a transcriptional cascade, with PNA1 identified as an upstream activator essential for early sexual development and ascospore production. Conversely, SUB1 was found to play a suppressive role, with knockout mutants exhibiting excessive protoperithecia due to abnormally high expression of MAT and pheromone-related genes. These findings highlight the central roles of PNA1 and SUB1 in regulating other gene activity related to sexual reproduction, contributing to a deeper understanding of the mechanisms of the multiple TFs that regulate sexual development.

Molecular insights into oocyte development and sperm storage in black rockfish (Sebastes schlegelii): Proteomic changes across reproductive stages

Sperm storage in females is widespread among vertebrates and insects, and the expression of proteins in the female reproductive tract is influenced by the presence of sperm, allowing for adaptation to this phenomenon. Through histological observation, we confirmed that sperm were stored in the isthmic fossa outside the oocyte during the post-mating (POM) stage, and closer to the epithelial cells during the pre-fertilization (PRF) stage. In addition, we observed asynchronous ovarian development in black rockfish, where oocytes at various stages could be identified during the PRF phase. This study investigated the ovarian protein expression changes in black rockfish (Sebastes schlegelii) during key reproductive stages: pre-mating (PRM), POM, unmated control (POM-CT), and PRF. A total of 5012 proteins were identified, with notable fluctuations in protein expression observed at the PRF stage. Specifically, 140 proteins were upregulated and 615 downregulated when compared to the PRM stage, while 101 proteins were upregulated and 531 downregulated in comparison to the POM stage. The functional enrichment analysis of differentially expressed proteins (DEPs) revealed distinct pathways: POM vs. PRM showed involvement in vesicle sorting and hormone signaling; PRF vs. POM indicated pathways related to chromatin remodeling and gene expression regulation; and POM vs. POM-CT highlighted pathways associated with immune response. These findings suggested that these signaling pathways may play a crucial role in oocyte development and sperm storage. The majority of DEPs were localized in the nucleus, with key interactions involving proteins such as GSK3B and MED1. These findings enhance our understanding of the molecular mechanisms underlying oocyte maturation and sperm storage, providing insights relevant to reproductive biology and aquaculture practices.

The genome of the simultaneously hermaphroditic snail Lymnaea stagnalis reveals an evolutionary expansion of FMRFamide-like receptors

The great pond snail Lymnaea stagnalis has served as a model organism for over a century in diverse disciplines such as neurophysiology, evolution, ecotoxicology and developmental biology. To support both established uses and newly emerging research interests we have performed whole genome sequencing (avg.176 × depth), assembly and annotation of a single individual derived from an inbred line. These efforts resulted in a final assembly of 943 Mb (L50 = 257; N50 = 957,215) with a total of 22,499 predicted gene models. The mitogenome was found to be 13,834 bp long and similarly organized as in other lymnaeid species, with minor differences in location of tRNA genes. As a first step towards understanding the hermaphroditic reproductive biology of L. stagnalis, we identified molecular receptors, specifically nuclear receptors (including newly discovered 2xDNA binding domain-NRs), G protein-coupled receptors, and receptor tyrosine kinases, that may be involved in the cellular specification and maintenance of simultaneously active male and female reproductive systems. A phylogenetic analysis of one particular family of GPCRs (Rhodopsin neuropeptide FMRFamide-receptor-like genes) shows a remarkable expansion that coincides with the occurrence of simultaneous hermaphroditism in the Euthyneura gastropods. As some GPCRs and NRs also showed qualitative differences in expression in female (albumen gland) and male (prostate gland) organs, it is possible that separate regulation of male and female reproductive processes may in part have been enabled by an increased abundance of receptors in the transition from a separate-sexed state to a hermaphroditic condition. These findings will support efforts to pair receptors with their activating ligands, and more generally stimulate deeper insight into the mechanisms that underlie the modes of action of compounds involved in neuroendocrine regulation of reproduction, induced toxicity, and development in L. stagnalis, and molluscs in general.

End of the Season Blues: Senescence and Reproductive Trade-Offs in Male Scorpions

Seasonal reproductive dynamics and senescence have profound impacts on male fertility, yet these processes remain understudied in scorpions. This study investigates how reproductive parameters—such as testicular mass, sperm quantity, and viability—change over the course of the reproductive season in Urophonius achalensis males. We found that early-season males exhibited higher sperm quality and testicular mass compared to their older counterparts, suggesting that senescence, rather than reproductive effort, drives the decline in sperm viability. Interestingly, isolated males accumulated more sperm without a reduction in viability, highlighting potential mechanisms that preserve sperm quality despite senescence. Body condition also played a key role, with males in better condition showing higher sperm counts but facing a sharper decline in sperm viability as the season progressed, suggesting trade-offs between early reproductive success and later-life reproductive costs. Our findings offer novel insights into the reproductive strategies of scorpions, emphasizing the interplay between senescence, environmental stressors, and reproductive investment. This work provides new insights into the reproductive biology of scorpions, with broader implications for understanding the role of senescence and mating systems in shaping reproductive strategies.