Search

Protogyny, being capable of changing from female to male during their lifetime, is prevalent in 20 families of teleosts but is believed to have evolved within specific evolutionary lineages. Therefore, shared regulatory factors governing the sex change process are expected to be conserved across protogynous fishes. However, a comprehensive understanding of this mechanism remains elusive. To identify these factors, we conducted a meta‐analysis using gonadal transcriptome data from seven species. We curated data pairs of ovarian tissue and transitional gonad, and employed ratios of expression level as a unified criterion for differential expression, enabling a meta‐analysis across species. Our approach revealed that classical sex change‐related genes exhibited differential expression levels between the ovary and transitional gonads, consistent with previous reports. These results validate our methodology's robustness. Additionally, we identified novel genes not previously linked to gonadal sex change in fish. Notably, changes in the expression levels of acetoacetyl‐CoA synthetase and apolipoprotein Eb, which are involved in cholesterol synthesis and transport, respectively, suggest that the levels of cholesterol, a precursor of steroid hormones crucial for sex change, are decreased upon sex change onset in the gonads. This implies a potential universal influence of cholesterol dynamics on gonadal transformation in protogyny. [ABSTRACT FROM AUTHOR]

Background: The deep-sea acorn worm Quatuoralisia malakhovi belongs to the phylum Hemichordata, class Enteropneusta, family Torquaratoridae, which was described in 2005. Owing to their epibenthic lifestyle and deep-sea habitat features, torquaratorids differ anatomically from shallow-water acorn worms; however, their morphology and fine structure are poorly studied. We have the opportunity to make three complete detailed series of histological sections of Q. malakhovi and to study the microscopic anatomy, histology and fine structure of the reproductive system of this acorn worm using scanning and transmission electron microscopy. Results: The sexes of Q. malakhovi are separate and indistinguishable externally. The lobed testes occupy the dorsal side of the genital wings and distinctly bulge into the peribranchial cavity by their mature lobes. The central part of the testis is always submerged into the genital wing and opens via a single gonad pore. The monociliary muscle cells stretch along the external wall of the testis and surround the gonad pore, probably taking part in the contraction of the testis lobes for spawning. The germinative epithelium of the testis contains spermatogenic cells at different stages of development and interstitial cells. Yolk cells are not found. Interstitial cells embrace the spermatogonia and spermatogenic columns, providing horizontal compartmentalization of the germinative epithelium, and contain numerous phagosomes with remnants of degenerating spermatogenic cells. The testis wall contains haemal lacunae, which are usually located on the side opposite the gonad pore. We describe the fine structure of spermatogonia, spermatocytes clustered in spermatogenic columns, spermatids, and spermatozoa. Spermatozoa are of the ectaquasperm type and consist of an acorn-shaped head and a flagellum 18–25 µm long. The sperm head includes a beak-shaped acrosomal part, a spherical nucleus and a midpiece containing a ring of 5 or rarely 6 mitochondria. Conclusions: The male reproductive system and sperm structure of Q. malakhovi, a representative of the family Torquaratoridae, have a number of differences from shallow-water acorn worms; however, the spermatogenesis and sperm structure of Q. malakhovi generally follow the pattern of the other three enteropneust families, and the phylogenetic significance of these deviations should be the subject of further research. [ABSTRACT FROM AUTHOR]

Pelophylax nigromaculatus is an important aquaculture economic animal in China, with an annual output of more than 80,000 tons in recent years. P. nigromaculatus demonstrates distinct sexual dimorphism, characterized by females being substantially larger than males. Consequently, the cultivation of female populations presents higher economic value. The RNA-Seq technology is harnessed in this study to delve into the sexual differentiation and reproductive mechanisms of these frogs. By analyzing the transcriptomes of mature testes and ovaries, 17.24 Gbp and 23.71 Gbp of clean data were obtained respectively. This analysis yielded 107,897 annotated genes, among which 8099 were differentially expressed; 4370 were upregulated and 3729 were downregulated in ovaries. GO and KEGG analyses highlighted 70 genes exhibiting sexual dimorphism. For validation, 13 differentially expressed genes were subjected to qRT-PCR, corroborating the results of transcriptome sequencing. Furthermore, the transcriptome analysis of P. nigromaculatus' sexual glands revealed 1,062,663 SNPs, with 676,172 (63.63%) and 386,491 (36.37%) being base conversion and base transversion sites, respectively. Utilizing excel for SNP site analysis, 35,406 SNPs were identified as significantly associated with the sex of P. nigromaculatus. In pursuit of sex-related markers, 100 SNP sites, aligning perfectly with male heterozygosity and female homozygosity, were randomly selected for amplification and sequencing. Through this approach, 134 SNPs were identified, 83 (61.94%) of which matched the transcriptome data. The findings of this study provide an invaluable resource for future functional research on sex-related genes of P. nigromaculatus and offer a foundation for the development of sex-related molecular markers. [ABSTRACT FROM AUTHOR]

Simple Summary: This research explores the role of the Cs-g2e3, a type of E3 ubiquitin ligase, in the gametogenesis of the Chinese Tongue Sole (Cynoglossus semilaevis), a marine fish known for its significant sexual dimorphism due to its unique chromosome system. E3 ubiquitin ligases are enzymes that help tag proteins for degradation or other regulatory functions and are involved in various biological processes, including gametogenesis. Our study focused on understanding how Cs-g2e3 influences gametogenesis—the process by which gametes or germ cells are produced. We found that Cs-g2e3 was highly expressed in the gonadal tissues of C. semilaevis, with its expression peaking at 8 months of age. By using techniques such as RNA interference, we discovered that the knockdown of Cs-g2e3 in ovarian and testicular germ cell lines significantly downregulated the expression of spermatogenesis-related and oogenesis-related genes. Additionally, we looked at how different transcription factors, which help turn genes on or off, affect the activity of the Cs-g2e3 promoter. Our findings highlight the crucial role of Cs-g2e3 in gametogenesis, suggesting its potential as a novel genetic tool that could significantly advance artificial reproduction technologies in aquaculture. Gametogenesis, the intricate developmental process responsible for the generation of germ cells (gametes), serves as a fundamental prerequisite for the perpetuation of the reproductive cycle across diverse organisms. The g2e3 enzyme is a putative ubiquitin E3 ligase implicated in the intricate regulatory mechanisms underlying cellular proliferation and division processes. The present study delves into the function of G2/M phase-specific E3 ubiquitin protein ligase (Cs-g2e3) in gametogenesis in Chinese Tongue Sole (Cynoglossus semilaevis). Sequence analysis shows that the Cs-g2e3 mRNA spans 6479 bp, encoding a 733 amino acid protein characterized by three conserved structural domains: PHD, RING, and HECT—typical of HECT E3 ubiquitin ligases. The predominant expression of Cs-g2e3 in the gonad tissues is further verified by qPCR. The expression profile of Cs-g2e3 in the gonads of the Chinese Tongue Sole is analyzed at different ages, and the results show that its expression peaks at 8 months of age and then begins to decline and stabilize. It is noteworthy that the expression level remains significantly elevated compared to that observed during the juvenile period. In situ hybridization shows that the mRNA of Cs-g2e3 is mainly localized in the germ cells of the ovary and the testis. RNA interference experiments show that the knockdown of Cs-g2e3 in ovarian and testicular germ cell lines significantly downregulates the expression of key genes involved in oogenesis (e.g., sox9 and cyp19a) and spermatogenesis (e.g., tesk1 and piwil2), respectively. Furthermore, the analysis of mutations in the transcription factor binding sites reveals that mutations within the Myogenin, YY1, and JunB binding sites significantly impact the transcriptional activity of the Cs-g2e3 gene, with the mutation in the YY1 binding site exhibiting the most pronounced effect (p < 0.001). This study contributes to a deeper understanding of the tissue-specific expression patterns of Cs-g2e3 across various tissues in Cynoglossus semilaevis, as well as the potential regulatory influences of transcription factors on its promoter activity. These findings may facilitate future research endeavors aimed at elucidating the expression and functional roles of the Cs-g2e3 gene. [ABSTRACT FROM AUTHOR]

Prostaglandin E2 (PGE2) has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates. Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding, which is believed to promote the commercial benefits of various mollusk species. In the present study, the contents of PGE2 in the gonads of abalone at different developmental stages (maturing stage, ripe stage, and spawning stage) and reproduction states (before and after spawning) were measured. A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages, and the highest PGE2 level was detected in the ovaries of female H. diversicolor in the UV-stimulated group. Then the effects of PGE2 injection on the spawning efficiency were explored, and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection. Through qRT-PCR and in situ hybridization assay, higher expression levels and wide distribution of phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), prostaglandin E synthases (PGES2), and prostaglandin E2 receptor 4 (EP4) in the gonads of H. diversicolor were observed after spawning. It is speculated that PGE2 may promote the reproductive cycle in both male and female H. diversicolor, although the regulation mechanism of PGE2 in female and male abalone might be different. The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future. [ABSTRACT FROM AUTHOR]

Abstract Background The deep-sea acorn worm Quatuoralisia malakhovi belongs to the phylum Hemichordata, class Enteropneusta, family Torquaratoridae, which was described in 2005. Owing to their epibenthic lifestyle and deep-sea habitat features, torquaratorids differ anatomically from shallow-water acorn worms; however, their morphology and fine structure are poorly studied. We have the opportunity to make three complete detailed series of histological sections of Q. malakhovi and to study the microscopic anatomy, histology and fine structure of the reproductive system of this acorn worm using scanning and transmission electron microscopy. Results The sexes of Q. malakhovi are separate and indistinguishable externally. The lobed testes occupy the dorsal side of the genital wings and distinctly bulge into the peribranchial cavity by their mature lobes. The central part of the testis is always submerged into the genital wing and opens via a single gonad pore. The monociliary muscle cells stretch along the external wall of the testis and surround the gonad pore, probably taking part in the contraction of the testis lobes for spawning. The germinative epithelium of the testis contains spermatogenic cells at different stages of development and interstitial cells. Yolk cells are not found. Interstitial cells embrace the spermatogonia and spermatogenic columns, providing horizontal compartmentalization of the germinative epithelium, and contain numerous phagosomes with remnants of degenerating spermatogenic cells. The testis wall contains haemal lacunae, which are usually located on the side opposite the gonad pore. We describe the fine structure of spermatogonia, spermatocytes clustered in spermatogenic columns, spermatids, and spermatozoa. Spermatozoa are of the ectaquasperm type and consist of an acorn-shaped head and a flagellum 18–25 µm long. The sperm head includes a beak-shaped acrosomal part, a spherical nucleus and a midpiece containing a ring of 5 or rarely 6 mitochondria. Conclusions The male reproductive system and sperm structure of Q. malakhovi, a representative of the family Torquaratoridae, have a number of differences from shallow-water acorn worms; however, the spermatogenesis and sperm structure of Q. malakhovi generally follow the pattern of the other three enteropneust families, and the phylogenetic significance of these deviations should be the subject of further research.

Prostaglandin E2 (PGE2) has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates. Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding, which is believed to promote the commercial benefits of various mollusk species. In the present study, the contents of PGE2 in the gonads of abalone at different developmental stages (maturing stage, ripe stage, and spawning stage) and reproduction states (before and after spawning) were measured. A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages, and the highest PGE2 level was detected in the ovaries of female H. diversicolor in the UV-stimulated group. Then the effects of PGE2 injection on the spawning efficiency were explored, and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection. Through qRT-PCR and in situ hybridization assay, higher expression levels and wide distribution of phospholipase A2 (PLA2), cyclooxygenase 2 (COX2), prostaglandin E synthases (PGES2), and prostaglandin E2 receptor 4 (EP4) in the gonads of H. diversicolor were observed after spawning. It is speculated that PGE2 may promote the reproductive cycle in both male and female H. diversicolor, although the regulation mechanism of PGE2 in female and male abalone might be different. The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future.

In the present study, 10 allotriploid (3nALT) and 10 allopentaploid (5nALP) six-month-old hybrid fish and two 3nALT and four 5nALP 40-month-old hybrid fish, which resulted by crossing female Russian sturgeon Acipenser gueldenstaedtii (Brandt and Ratzeberg, 1833) and male American paddlefish Polyodon spathula (Walbaum, 1792), were investigated. It was revealed that six-month-old 3nALT and 5nALP hybrids initially had "undifferentiated" gonads, while in the 40-month-old hybrids, only testes were observed in one case of 3nALT and one case of 5nALP hybrids. The testis of 3nALT hybrids was partially developed with spermatogonia, while the testis of one 5nALP hybrid was in the second developmental stage with low spermatogonia density. We could not determine gonad differentiation in any of the cases when the hybrid individuals had the W sex chromosome. We concluded that the gonad differentiation of these interfamilial hybrids follows a similar pattern to interspecific hybrids of different ploidy parent species of the family Acipenseridae, which is consistent with the classical Haldane's rule. However, it cannot be excluded that the testis of this/these hybrid(s) may produce fertile sperm after sexual maturity, depending on additional genetic, hormonal and environmental factors, and further research is required for its evaluation. [ABSTRACT FROM AUTHOR]

Monitoring the maturation of fish gonads requires an understanding of the locations of reproductive hormone formation both under the influence of environmental factors and under normal conditions. A crucial role in the biosynthesis of active steroid hormones is played by 3β-hydroxysteroid dehydrogenase (3β-HSD). The male and female Oreochromis niloticus gonads at different stages of the annual sexual cycle were analyzed for 3β-HSD using histochemical techniques to pinpoint the locations of steroid synthesis. In females, a specific cell type in the thecal layer, interstitial cells, and ovarian wall epithelial cells exhibited 3β-HSD activity. In males, only Leydig cells (interstitial cells) and lobule boundary cells exhibited 3β-HSD activity. During the stages of sexual maturation and spawning, the Leydig cells' steroidogenic activity increased. Additionally, during the maturing and spawning stages, 3β-HSD exhibited a strong reaction that increased in intensity and the apparent quantity of cells exhibiting a reaction. However, after spawning, the reaction decreased. Furthermore, during the oogenesis process, which is the development of the previtellogenic oocytes to the ripe oocytes, 3β-HSD activity was elevated in the various phases of ovarian maturation. In conclusion, it can be stated that the cells producing steroid hormones in the male and female gonads of O. niloticus have been sufficiently identified, and their steroid hormoneproducing capacity has been demonstrated. Naturally, more research is necessary to apply this finding to the development of fish gonads during the reproduction in aquaculture settings or under situations where this teleost species is concerned to environmental treatments. [ABSTRACT FROM AUTHOR]

ABSTRACT: Direct introduction of cryopreserved embryonic gonadal germ cells (GGC) into a sterile chicken surrogate host to reconstitute a chicken breed has been demonstrated as a feasible approach for preserving and utilizing chicken genetic resources. This method is highly efficient using male gonads; however, a large number of frozen female embryonic gonads is needed to provide sufficient purified GGC for the generation of fertile surrogate female hosts. Applying this method to indigenous chicken breeds and other bird species is difficult due to small flock numbers and poor egg production in each egg laying cycle. Propagating germ cells from the frozen gonadal tissues may be a solution for the biobanking of these birds. Here, we describe a simplified method for culture of GGC from frozen embryonic 9.5 d gonads. At this developmental stage, the germ cells are autonomously shed into medium, yielding hundreds to thousands of mitosis-competent germ cells. The resulting cultures of GGC have over 90% purity, uniformly express SSEA-1 and DAZL antigens and can re-colonize recipient's gonads. The GGC recovery rate from frozen gonads are 42% to 100%, depending on length of cryopreservation and the breed or line of chickens. Entire chicken embryos can also be directly cryopreserved for later gonadal isolation and culture. This storage method is a supplementary approach to safeguard local indigenous chicken breeds bearing valuable genetic traits and should be applicable to the biobanking of many bird species.

The greater amberjack Seriola dumerili is economically important in both capture fisheries and aquaculture. It is a gonochoristic species with no noticeable sexual dimorphism, usually reaching maturity at 3–4 years. Spawning occurs in the Pacific from May to June but varies between regions. During a study on the maturity of greater amberjack, abnormal hermaphrodites (AH) with ovotestes were found. Of the 51 fish examined from June 2017 to April 2018, 2 individuals (3.9%) were classified as AH, with one each identified in February and April 2018. These AHs were larger than the gonochoristic (GC) individuals of the same age. In February, both AH and GCs had sperm-filled seminal lobules and ovaries at the primary yolk stage. By April, atresias were seen in both the AHs and GCs. While oocyte diameter increased in both AHs and GCs between February and April, the gonadosomatic index was lower in AHs. Plasma estradiol-17β and 11-ketotestosterone levels of AHs were similar to those of male GCs. These results suggest that AHs have accelerated growth with potential maturation as functional males. This is the first report on hermaphroditism in the Seriola genus. [ABSTRACT FROM AUTHOR]

Simple Summary: Siganus oramin, as a commercial species, is a well-received table fish in southeastern China. However, valuable reproduction-related data are still scarce. In the present study, gonad transcriptome analysis was first performed using Illumina Novaseq technology. Comparative transcriptome analysis of adult male and female gonads identified a large number of differentially expressed genes. Among them, many reproduction-related genes that play important roles in gonad differentiation and development were found. These data may contribute greatly to the regulation of rabbitfish reproduction. The rabbitfish, Siganus oramin, is a commercially important table fish in southeastern China. However, there have been few studies on its gonad development and reproduction regulation. Comparative transcriptome analysis was first performed on adult male and female gonads of S. oramin. In total, 47,070 unigenes were successfully assembled and 22,737 unigenes were successfully annotated. Through comparative transcriptome analysis of male and female gonads, a total of 6722 differentially expressed genes were successfully identified, with 3528 upregulated genes and 3154 downregulated genes in the testes. In addition, 39 differentially expressed reproduction-related genes were identified. Finally, quantitative real-time PCR was used to validate the expression levels of several differentially expressed genes. These results provide important data for further studying the function of reproduction-related genes and the molecular mechanism regulating gonad development and reproduction in S. oramin. [ABSTRACT FROM AUTHOR]

Wild zebrafish (Danio rerio) have a ZZ/ZW chromosomal sex-determination system with the major sex locus on the right arm of chromosome-4 (Chr4R) near the largest heterochromatic block in the genome, suggesting that Chr4R transcriptomics might differ from the rest of the genome. To test this hypothesis, we conducted an RNA-seq analysis of adult ZW ovaries and ZZ testes in the Nadia strain and identified 4 regions of Chr4 with different gene expression profiles. Unique in the genome, protein-coding genes in a 41.7 Mb section (Region-2) were expressed in testis but silent in ovary. The AB lab strain, which lacks sex chromosomes, verified this result, showing that testis-biased gene expression in Region-2 depends on gonad biology, not on sex-determining mechanism. RNA-seq analyses in female and male brains and livers validated reduced transcripts from Region-2 in somatic cells, but without sex specificity. Region-2 corresponds to the heterochromatic portion of Chr4R and its content of genes and repetitive elements distinguishes it from the rest of the genome. Region-2 lacks protein-coding genes with human orthologs; has zinc finger genes expressed early in zygotic genome activation; has maternal 5S rRNA genes, maternal spliceosome genes, a concentration of tRNA genes, and a distinct set of repetitive elements. The colocalization of (1) genes silenced in ovaries but not in testes that are (2) expressed in embryos briefly at the onset of zygotic genome activation; (3) maternal-specific genes for translation machinery; (4) maternal-specific spliceosome components; and (5) adjacent genes encoding miR-430, which mediates maternal transcript degradation, suggest that this is a maternal-to-zygotic-transition gene regulatory block. [ABSTRACT FROM AUTHOR]

The germline provides the genetic and non-genetic information that passes from one generation to the next. Given this important role in species propagation, egg and sperm precursors, called primordial germ cells (PGCs), are one of the first cell types specified during embryogenesis. In fact, PGCs form well before the bipotential somatic gonad is specified. This common feature of germline development necessitates that PGCs migrate through many tissues to reach the somatic gonad. During their journey, PGCs must respond to select environmental cues while ignoring others in a dynamically developing embryo. The complex multi-tissue, combinatorial nature of PGC migration is an excellent model for understanding how cells navigate complex environments in vivo. Here, we discuss recent findings on the migratory path, the somatic cells that shepherd PGCs, the guidance cues somatic cells provide, and the PGC response to these cues to reach the gonad and establish the germline pool for future generations.We end by discussing the fate of wayward PGCs that fail to reach the gonad in diverse species. Collectively, this field is poised to yield important insights into emerging reproductive technologies. [ABSTRACT FROM AUTHOR]

In holometabolous insects, extensive reorganisation of tissues and cells occurs at the pupal stage. The remodelling of the external exoskeleton and internal organs that intervenes during metamorphosis has been traditionally studied in many insect species based on histological or ultrastructural methods. This study demonstrates the use of synchrotron X-ray phase-contrast micro-computed tomography as a powerful, non-destructive tool for in situ morphological observation of anatomical structures at the pupal stage in two Tenebrionid beetles, i.e. Tribolium castaneum and Tenebrio molitor, known as important pests, as well as emerging and promising models in experimental biology. Virtual sections and three-dimensional reconstructions were performed on both males and females at early, intermediate, and late pupal stage. The dataset allowed us to observe the remodelling of the gut and nervous system as well as the shaping of the female and male reproductive system at different pupal ages in both mealworm and red flour beetles. Moreover, we observed that the timing and duration pattern of organ development varied between the species analysed, likely related to the species-specific adaptations of the pre-imaginal stages to environmental conditions, which ultimately affect their life cycle. This research provides new knowledge on the morphological modifications that occur during the pupal stage of holometabolous insects and provides a baseline set of information on beetle metamorphosis that may support future research in forensics, physiology, and ecology as well as an image atlas for educational purposes. [ABSTRACT FROM AUTHOR]

This study investigates the presence and concentrations of ten specific heavy metals in the muscle tissues and gonads of three commercially important marine fish species: Garfish (Belone belone), European barracuda (Sphyraena sphyraena), and Anglerfish (Lophius piscatorius) collected from the Aegean Sea in Türkiye. The results indicate variations in metal accumulation, both between genders and among species. The fish species tend to accumulate higher levels of heavy metals in their gonads than in muscle tissues (p<0.05). While Cr, Cd, and Pb were not detected, Zn, Cu, and Fe are the predominant metals in muscle tissues due to their essential biological roles. However, within toxic elements, Hg was predominant, and L. piscatorius , a benthic fish, exceeded its recommended safety limits. A health risk assessment suggests that except for L. piscatorius , consuming these fish species from the Aegean Sea is generally safe, with estimated weekly intake (EWI) values below permissible limits. Total Hazard Quotient (THQ) values for most metals are below 1, indicating no significant non-carcinogenic health risks for consumers. This study emphasizes the critical need for regularly monitoring heavy metal levels in marine fish from the Aegean Sea, Turkiye. While overall safety in consuming these fish is highlighted, exceptions exist, notably concerning Hg levels in L. piscatorius. Therefore, persistent monitoring of heavy metal concentrations, especially in L. piscatorius , is advised to ensure ongoing safety and mitigate potential risks of metal accumulation. [ABSTRACT FROM AUTHOR]

Loaches are highly nutritious and global demand has been recognized for only few species especially of ornamental importance. Lepidocephalichthys thermalis is an important food species of loach fetching high market price but there is limited data related to its nutritional requirements and reproductive biology. Therefore, a detailed study was carried out to analyze the effect of vitamin enriched diets on the captive maturation and breeding performance of L. thermalis. Vitamins A, C and E were incorporated at three different doses in basal feed containing 23% C.P and fed to brooders for a period of 90 days. Fecundity, GSI, gonad histology, hormone (cortisol and progesterone) variations, breeding performance and growth parameters were recorded. Significant differences in the growth and breeding performance of female brooder under different treatments were noted. Among the selected vitamins, incorporation of vitamin C at 150 mg/kg of diet resulted in maximum mean weight gain (2.51 ± 0.043 g), mean weight gain percentage (70.74 ± 1.219), mean DGR (0.16 ± 0.003) and mean SGR (3.13 ± 0.0037). Based on the histological observation, maximum maturity of L. thermalis was obtained when fed with diet incorporated with 200 mg/kg vitamin E. All the treatments recorded higher mean estimated growth and maturation parameters when compared to control and were significantly different (p<0.05). The results obtained were statistically analysed using One way ANOVA following Duncan multiple range test in SPSS-22.0 to compare the significant differences in growth parameters among all treatments and discussion was made in the light of available literatures. [ABSTRACT FROM AUTHOR]

Sea hare gonad and moringa leaf contain essential nutrients for growth and tissue formation and have physiological effects on the body. The research was to study the effects of sea hare gonad flour and moringa leaf flour formula on body weight and Hemoglobin (Hb) levels in female Wistar anemic rats. This research was conducted in a laboratory using a randomized control pretest-posttest design. The study sample consisted of 30 female Wistar rats (Rattus norvegicus) aged 5-7 months and weighing 100-150 g, all of which were anemic. The rats were divided into five treatment groups: K+ received 1.1 mg/week of iron supplementation, K- received no treatment, F1 received 3 g of sea hare gonad formula, F2 received 3 g of sea hare gonad formula and 1 g of moringa leaf flour, and F3 received 3 g of sea hare gonad formula and 2 g of moringa leaf flour. The intervention lasted for 24 days, and measurements of body weight and Hb levels were taken before and after the intervention. The change in body weight before and after the intervention in each group was as follows: K-=51.5±17.1 g, K+=-41.2±2.6 g, F1=14.3±5.7 g, F2=30.4±8.6 g, and F3=55.1±16.2 g. There was a significant difference in the increase in body weight among the groups (p=0.002). Hb levels also increased after the intervention, with changes as follows: K-=-2.56±0.95 g, K+=9.10±1.87 g, F1=7.10±1.2 g, F2=8.68±0.22 g, and F3=8.98±2.7 g. There was a significant difference in the increase in Hb levels among the intervention groups (p=0.000). The administration of sea hare gonad formula and moringa leaf flour can increase body weight and Hb levels in female anemic rats. This finding suggests the potential use of these ingredients as beneficial nutritional supplements to improve nutritional status in individuals with anemia.

Sea urchin (Mesocentrotus nudus) is a commercially significant mariculture species, with its gonads being the exclusive edible parts for humans. Identifying sex-related genes is an effective approach for elucidating the underlying molecular mechanisms of gonad development in sea urchins. Some cytochrome P450 (CYP) superfamily members play critical roles in sex differentiation, steroid hormone biosynthesis, and ovarian steroidogenesis. In the present study, we identified 83 CYPs assigned to 17 families from the gonadal transcriptomic data of M. nudus, with most CYPs clustering within the CYP 2 family branches. Furthermore, we identified 11 gender-biased CYPs, including CYP 17A1, CYP 2, CYP 3A24, CYP 4V2, and CYP 46A1, as well as 11 CYPs related to steroid hormone biosynthesis, including CYP 1A1, CYP 1A5, CYP 3, and CYP 17A1. The expression patterns of those candidate sex-related CYP genes were also analyzed. The findings lay the foundation for further investigating the role of CYPs in the endogenous synthesis of sex steroids, offering valuable insights into the molecular mechanisms underlying sex differentiation in sea urchins.

Gametogenesis, the intricate developmental process responsible for the generation of germ cells (gametes), serves as a fundamental prerequisite for the perpetuation of the reproductive cycle across diverse organisms. The g2e3 enzyme is a putative ubiquitin E3 ligase implicated in the intricate regulatory mechanisms underlying cellular proliferation and division processes. The present study delves into the function of G2/M phase-specific E3 ubiquitin protein ligase (Cs-g2e3) in gametogenesis in Chinese Tongue Sole (Cynoglossus semilaevis). Sequence analysis shows that the Cs-g2e3 mRNA spans 6479 bp, encoding a 733 amino acid protein characterized by three conserved structural domains: PHD, RING, and HECT—typical of HECT E3 ubiquitin ligases. The predominant expression of Cs-g2e3 in the gonad tissues is further verified by qPCR. The expression profile of Cs-g2e3 in the gonads of the Chinese Tongue Sole is analyzed at different ages, and the results show that its expression peaks at 8 months of age and then begins to decline and stabilize. It is noteworthy that the expression level remains significantly elevated compared to that observed during the juvenile period. In situ hybridization shows that the mRNA of Cs-g2e3 is mainly localized in the germ cells of the ovary and the testis. RNA interference experiments show that the knockdown of Cs-g2e3 in ovarian and testicular germ cell lines significantly downregulates the expression of key genes involved in oogenesis (e.g., sox9 and cyp19a) and spermatogenesis (e.g., tesk1 and piwil2), respectively. Furthermore, the analysis of mutations in the transcription factor binding sites reveals that mutations within the Myogenin, YY1, and JunB binding sites significantly impact the transcriptional activity of the Cs-g2e3 gene, with the mutation in the YY1 binding site exhibiting the most pronounced effect (p < 0.001). This study contributes to a deeper understanding of the tissue-specific expression patterns of Cs-g2e3 across various tissues in Cynoglossus semilaevis, as well as the potential regulatory influences of transcription factors on its promoter activity. These findings may facilitate future research endeavors aimed at elucidating the expression and functional roles of the Cs-g2e3 gene.

The mechanism of fish gonadal sex differentiation is complex and regulated by multiple factors. It has been widely known that proper steroidogenesis in Leydig cells and sex-related genes in Sertoli cells play important roles in gonadal sex differentiation. In teleosts, the precise interaction of these signals during the sexual fate determination remains elusive, especially their effect on the bi-potential gonad during the critical stage of sexual fate determination. Recently, all-testis phenotypes have been observed in the cyp17a1-deficient zebrafish and common carp, as well as in cyp19a1a-deficient zebrafish. By mating cyp17a1-deficient fish with transgenic zebrafish Tg(piwil1:EGFP-nanos3UTR), germ cells in the gonads were labelled with enhanced green fluorescent protein (EGFP). We classified the cyp17a1-deficient zebrafish and their control siblings into primordial germ cell (PGC)-rich and -less groups according to the fluorescence area of the EGFP labelling. Intriguingly, the EGFP-labelled bi-potential gonads in cyp17a1+/+ fish from the PGC-rich group were significantly larger than those of the cyp17a1−/− fish at 23 days post-fertilization (dpf). Based on the transcriptome analysis, we observed that the cyp17a1-deficient fish of the PGC-rich group displayed a significantly upregulated expression of amh and gsdf compared to that of control fish. Likewise, the upregulated expressions of amh and gsdf were observed in cyp19a1a-deficient fish as examined at 23 dpf. This upregulation of amh and gsdf could be repressed by treatment with an exogenous supplement of estradiol. Moreover, tamoxifen, an effective antagonist of both estrogen receptor α and β (ERα and Erβ), upregulates the expression of amh and gsdf in wild-type (WT) fish. Using the cyp17a1- and cyp19a1a-deficient zebrafish, we provide evidence to show that the upregulated expression of amh and gsdf due to the compromised estrogen signaling probably determines their sexual fate towards testis differentiation. Collectively, our data suggest that estrogen signaling inhibits the expression of amh and gsdf during the critical time of sexual fate determination, which may broaden the scope of sex steroid hormones in regulating gonadal sex differentiation in fish. [ABSTRACT FROM AUTHOR]

To investigate the impact of heavy metals on the physiology of aquatic organisms, previous studies have focused on selected biomarker measurements in samples. However, most studies do not take into account toxicity effects on both males and females. The present paper aims to examine the effect of sex on the detoxification response using metallothioneins (MTs), a biomarker of metallic contamination. MTs were measured in different organs (mantle, digestive gland and gonad) of both males and females of Donax trunculus L. (Mollusca, Bivalvia) exposed to cadmium (Cd). The samples were collected at El Battah beach, far from any source of pollution, and reared in the laboratory for four days. Cd was added to the rearing water at two previously determined sublethal concentrations (LC10 and LC25). Measurements of MTs were made at (0, 48 and 96 h). Cd exposure caused a significant induction (P < 0.05) of MTs in all studied organs in both sexes with a marked effect in females. The digestive gland had the highest MT levels, followed by the gonad and then mantle. Female and male individuals of this species differ in their susceptibility to Cd. This study supports the importance of sex and tissue in ecotoxicological studies. [ABSTRACT FROM AUTHOR]

Several studies demonstrated adverse effects associated with exposure to polystyrene nanoplastics (NPs), such as toxicity, inflammation, or other health-related concerns. This study aims to analyse the impact of NPs exposure on pro-inflammatory cytokine levels and testicular histology in tilapia gonads. Twenty-four male tilapias were used in this study and divided into four groups, including a control (commercial pellets only) and three treatment groups (commercial feed mixed 0.5, 1.0 and 2.0 µL/kg of NPs, respectively) for 25 days. Blood sample was used to tumor necrosis factorα (TNF-α) and interferon-γ (IFN-ɣ) levels analysis. Histology of testicular tissue was prepared with hematoxylin and eosin (HE) staining. The results showed that NPs exposure has no significant influence of TNF-α and IFN-ɣ levels. The levels of TNF-α on the control (1.6 ± 0.3 ng/mL) and the treatment groups from low to high concentration (1.7± 0.4; 1.7 ± 0.4; and 1.6 ± 0.3 ng/mL) and the levels of IFN-γ control (16.7 ± 2.8 ng/mL) and the treatment groups (19.1 ± 5.3; 18.7 ± 4.2; and 19.8 ± 3.5 ng/mL). Polystyrene nanoplastics exposure can reduce the number of spermatogenic cells. Spermatogonia cells was decreased from 27.5 ± 0.9 to 13.1 ± 1.1 cells/cyst. Spermatocyte cell was decreased from 57.6 ± 0.6 to 18.5 ± 0.3 cells/cyst. Spermatid cells was decreased from 86.8 ± 2.7 to 38.5 ± 2.7. In conclusion, exposure to multiple doses of NPs for 25 days did not increase pro-inflammatory cytokines levels in the blood serum of tilapia, but it caused histological changes in the gonads of fish. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the nutrient quality of Scylla paramammosain feeding with formulated feed and chilled trash fish. Crabs weighing (8.52±0.34) g were divided into two groups and fed with formulated feed and chilled trash fish for 42 d. Muscle and sexual gonad were separated for nutrient analysis at the end of the experiment. The results showed that the muscle of the group fed with formulated feed had significantly lower moisture, higher crude protein and crude ash content than the group fed with chilled trash fish (P<0.05); the sexual gonad had higher moisture, lower crude protein, crude lipid and crude ash than the group fed with chilled trash fish. The muscle of Scylla paramammosain fed with formulated feed has higher total amino acid (TAA), essential amino acid (EAA) and favor amino acid (FAA) contents than the group fed with chilled trash fish. The muscle of the group fed with formulated feed had higher amino acid score (AAS) for isoleucine and valine, lower AAS for lysine; higher chemical score (CS) for isoleucine, lower CS for phenylalanine+tyrosine and lysine; higher EAAI than the group fed with chilled trash fish. The sexual gonad of the group fed with formulated feed had lower AAS for isoleucine, leucine, threonine and phenylalanine+tyrosine; higher lysine, valine, methionine+cystine; lower CS for isoleucine, leucine, phenylalanine+tyrosine, higher CS for lysine, valine, methionine+cystine; higher EAAI than the group fed with chilled trash fish. The muscle of Scylla paramammosain fed with formulated feed has higher DHA, EPA, n6-PUFA, n3-PUFA ratio than the group fed with chilled trash fish; The sexual gonad of the group fed with formulated feed has higher DHA and lower EPA than the group fed with chilled trash fish. In summary, the muscles and gonads of the Scylla paramammosain fed with formulated feed had higher EAAI index and protein quality than the group fed with the chilled trash fish, which suggests that nutrient composition of the Scylla paramammosain can be affected by feed composition. [ABSTRACT FROM AUTHOR]

Simple Summary: The adductor muscles of scallops are highly prized for their exceptional taste and nutritional value. Additionally, by-products of scallops show potential for the production of functional foods, animal feed, and nutraceuticals. To address the paucity of information regarding the amino acid composition of Iceland scallops from the coastal Barents Sea, we conducted biochemical analyses of various tissues from this species. Our findings revealed the highest contents of glycine and arginine, two amino acids widely implicated in the physiological processes of scallops worldwide. The consistency of amino acid composition across the muscle, gonad, and mantle tissues, as well as their lack of differentiation between male and female scallops, was noteworthy. A negative correlation was observed between the gonad index and amino acid contents in the muscle, while a positive relationship was found between muscle amino acid content and depth. Furthermore, amino acid contents in the mantle demonstrated a positive correlation with water temperature. Scallop by-products hold significant promise for the food and pharmaceutical industries. The Iceland scallop from the Barents Sea is a commercially important species with promising aquaculture potential, but information on the biochemical properties of its tissues is limited. Our analysis of the adductor muscle, gonad, and mantle of this bivalve mollusk from coastal waters provided insight into its amino acid composition. Biochemical analysis revealed predominant levels of glycine (11.8, 11.5, and 9.6 mg g−1, respectively) and arginine (11.2, 8.3, and 5.8 mg g−1, respectively). While multivariate comparisons did not reveal significant differences in amino acid composition between the tissues, single comparisons showed significantly higher levels of arginine and leucine in the adductor muscle compared to those of the mantle. The abundant presence of glycine and arginine underscores their importance in maintaining basic physiological processes, consistent with other scallop species. Redundancy analysis identified water depth and scallop gonad index as influential factors shaping the amino acid profile in the adductor muscle. In the case of the mantle, water temperature emerged as the main driver of amino acid content. Our results confirm the richness of essential amino acids in scallop by-products and highlight their potential for human consumption, production of feed ingredients for farmed animals, and nutraceuticals. [ABSTRACT FROM AUTHOR]

Simple Summary: Gonads are organs such as testes and ovaries. They are organs with completely different structures which arise in development from common sexually undifferentiated primordia. The development of gonads has been well-studied only in some vertebrates, and lizards remain one of the groups with the least-explored gonadal development. In this study, we analyzed changes in the structure of developing gonads in three species of geckos from the formation of gonadal ridges, the primordia of gonads, through the sexual differentiation of gonads, to the formation of testes and ovaries. We showed that the earliest manifestation of the sexual differentiation of gonads is the differentiation in the thickness of the gonadal cortex and the number of cortical germ cells. The development of gecko gonads was characterized by a different tendency of the ovarian medulla to form cords. The ovarian cortex was thickened at the pole of the gonad and thin near the mesogonium. In differentiating testes, lumens formed very early. This study indicated a number of unique features in the development of geckos, as well as a number of common features in the development of their gonads and other vertebrates. Reptiles constitute a highly diverse group of vertebrates, with their evolutionary lineages having diverged relatively early. The types of sex determination exemplify the diversity of reptiles; however, there are limited data regarding the gonadal development in squamate reptiles. Geckos constitute a group that is increasingly used in research and that serves as a potential reptilian model organism. The aim of this study was to trace the changes in the structure of developing gonads in the embryos of three gecko species: the crested gecko, leopard gecko, and mourning gecko. These species represent different families of the Gekkota infraorder and exhibit different types of sex determination. Gonadal development was examined from the formation of the earliest gonadal ridges through the development of undifferentiated gonadal structures, sex differentiation of gonads, and the formation of testicular and ovarian structures. The study showed that the gonadal primordia of these three gecko species formed on the most dorsally located surface of the dorsal mesentery, and both the coelomic epithelium and the nephric mesenchyme contributed to their development. As in other reptile species, primordial germ cells settled in the gonadal ridges, and the undifferentiated gonad was composed of a cortex and a medulla. Ovarian differentiation started with the thickening of the gonadal cortex and proliferation of germ cells in this region. A characteristic feature of the developing gecko ovaries was the thickened crescent-shaped cortex on the medial and ventral surfaces of the ovaries. The ovarian medulla also grew and exhibited diverse tendencies to form cords. In the leopard gecko, advanced cord-like structures with lumens were observed in the ovaries, which were not seen in the crested gecko. Testicular differentiation was characterized by cortical thinning and the disappearance of germ cells in this region. In the medulla, the development of distinct cords with early lumen formation was noted. A characteristic feature of embryonic gonads was their growth in a horizontal plane. In this study, gonadal development was characterized by several features that are shared by geckos and other reptiles, along with features that are specific only to geckos. [ABSTRACT FROM AUTHOR]

In vertebrates, species exhibit phenotypic plasticity of sex determination that the sex can plastically be determined by the external environmental temperature through a mechanism, temperature‐dependent sex determination (TSD). Temperature exerts influence over the direction of sexual differentiation pathways, resulting in distinct primary sex ratios in a temperature‐dependent manner. This review provides a summary of the thermal sensitivities associated with sex determination in reptiles and amphibians, with a focus on the pattern of TSD, gonadal differentiation, temperature sensing, and the molecular basis underlying thermal sensitivity in sex determination. Comparative studies across diverse lineages offer valuable insights into comprehending the evolution of sex determination as a phenotypic plasticity. While evidence of molecular mechanisms governing sexual differentiation pathways continues to accumulate, the intracellular signaling linking temperature sensing and sexual differentiation pathways remains elusive. We emphasize that uncovering these links is a key for understanding species‐specific thermal sensitivities in TSD and will contribute to a more comprehensive understanding of ecosystem and biodiversity conservations. Research Highlights: This review focused on gonadal development of reptiles and amphibians. We showed that temperature stimuli produce distinct primary sex ratio across species, and discussed the species‐specific temperature perception. [ABSTRACT FROM AUTHOR]

Reproductive processes are regulated by a variety of neuropeptides in vertebrates and invertebrates. In starfish (phylum Echinodermata), relaxin‐like gonad‐stimulating peptide triggers oocyte maturation and spawning. However, little is known about other neuropeptides as potential regulators of reproduction in starfish. To address this issue, here, we used histology and immunohistochemistry to analyze the reproductive system of the starfish Asterias rubens at four stages of the seasonal reproductive cycle in male and female animals, investigating the expression of eight neuropeptides: the corticotropin‐releasing hormone‐type neuropeptide ArCRH, the calcitonin‐type neuropeptide ArCT, the pedal peptide‐type neuropeptides ArPPLN1b and ArPPLN2h, the vasopressin/ocytocin‐type neuropeptide asterotocin, the gonadotropin‐releasing hormone‐type neuropeptide ArGnRH, and the somatostatin/allatostatin‐C‐type neuropeptides ArSS1 and ArSS2. The expression of five neuropeptides, ArCRH, ArCT, ArPPLN1b, ArPPLN2h, and asterotocin, was detected in the gonoducts and/or gonads. For example, extensive ArPPLN2h expression was revealed in the coelomic epithelial layer of the gonads throughout the seasonal reproductive cycle in both males and females. However, seasonal and/or sexual differences in the patterns of neuropeptide expression were also observed. Informed by these findings, the in vitro pharmacological effects of neuropeptides on gonad preparations from male and female starfish were investigated. This revealed that ArSS1 causes gonadal contraction and that ArPPLN2h causes gonadal relaxation, with both neuropeptides being more effective on ovaries than testes. Collectively, these findings indicate that multiple neuropeptide signaling systems are involved in the regulation of reproductive function in starfish, with some neuropeptides exerting excitatory or inhibitory effects on gonad contractility that may be physiologically relevant when gametes are expelled during spawning. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangxi Normal University - Natural Science Edition is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the role of the nuclear receptor NR5A1 in the testis after sex determination, we analyzed mice lacking NR5A1 in Sertoli cells (SCs) from embryonic day (E) 13.5 onwards. Ablation of Nr5a1 impaired the expression of genes characteristic of SC identity (e.g. Sox9 and Amh), caused SC death from E14.5 onwards through a Trp53-independent mechanism related to anoikis, and induced disorganization of the testis cords. Together, these effects caused germ cells to enter meiosis and die. Single-cell RNA-sequencing experiments revealed that NR5A1-deficient SCs changed their molecular identity: some acquired a 'pre-granulosa-like' cell identity, whereas other reverted to a 'supporting progenitor-like' cell identity, most of them being 'intersex' because they expressed both testicular and ovarian genes. Fetal Leydig cells (LCs) did not display significant changes, indicating that SCs are not required beyond E14.5 for their emergence or maintenance. In contrast, adult LCs were absent from postnatal testes. In addition, adult mutant males displayed persistence of Mullerian duct derivatives, decreased anogenital distance and reduced penis length, which could be explained by the loss of AMH and testosterone synthesis due to SC failure. [ABSTRACT FROM AUTHOR]

Concentrations of aluminum, chromium, cobalt, nickel, cadmium, lead, manganese, iron and zinc were determined in sea urchin species, Diadema setosum from Iskenderun Bay in December 2022. The level of metals was determined by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Concentrations of the heavy metals in the examined sea urchins ranged as follows: Al 0.07-7.17 μg g-1; Cr 0.07–0.8 μg g-1; Co 0.01–0.2 μg g-1; Ni 0.2–2.9 μg g-1; Cd 0.0–0.02 μg g-1; Pb 0.4-3.5 μg g-1; Mn 0.03–0.4 μg g-1; Fe 1.2-57.2 μg g-1; Zn 0.28–2.7 μg g-1, respectively. The highest accumulation of Fe and Pb metals was determined in the tissues of the sea urchin. The present study suggests that D. setosum could be a potential biological indicator of metal pollution in the Iskenderun Bay. Furthermore, soft tissues generally had lower levels overall. For this reason, the data show that D. setosum is a very good heavy metal collector and therefore may be used successfully to monitor heavy metal levels in Iskenderun Bay. [ABSTRACT FROM AUTHOR]

Groupers, highly valued fish globally, exhibit sex change from female to male during adulthood, posing challenges in obtaining wild males for aquaculture. Inducing female-to-male sex reversal in juvenile groupers can streamline breeding efforts. This study used 17α-Methyltestosterone (MT)-loaded cholesterol pellets to treat one-year-old longtooth groupers (Epinephelus bruneus) and induce small functional males. Gonadal sexuality and male functionality were assessed after one to two months. Initial gonadal changes included efferent duct differentiation. High-dose MT-treated fish exhibited active spermatogenesis. However, no spermiation was observed. This highlights MT's potential for sex reversal but not for complete testicular function. These findings have implications for grouper aquaculture and the management of sex change. Further research should explore methods to optimize functional male induction for sustainable breeding practices. [ABSTRACT FROM AUTHOR]

Coilia nasus is an anadromous fish that has been successfully domesticated in the last decade due to its high economic value. The fish exhibits a delayed ovary development during the reproductive season, despite breeding and selection for five to six offspring. The molecular mechanism of the delayed ovary development is still unknown, so the obstacles have not been removed in the large-scale breeding program. This study aims to investigate the key genes regulating ovarian development by comparing the transcriptomes of ovarian-stage IV and stage II brain/pituitary of Coilia nasus. Ovarian stages were validated by histological sections. A total of 75,097,641 and 66,735,592 high-quality reads were obtained from brain and pituitary transcriptomes, respectively, and alternatively spliced transcripts associated with gonadal development were detected. Compared to ovarian Ⅱ- brain, 515 differentially expressed genes (DEGs) were upregulated and 535 DEGs were downregulated in ovarian Ⅳ- brain, whereas 470 DEGs were upregulated and 483 DEGs were downregulated in ovarian Ⅳ- pituitary compared to ovarian Ⅱ- pituitary. DEGs involved in hormone synthesis and secretion and in the GnRH signaling pathway were screened. Weighted gene co-expression network analysis identified gene co-expression modules that were positively correlated with ovarian phenotypic traits. The hub genes Smad4 and TRPC4 in the modules were co-expressed with DEGs including Kiss1 receptor and JUNB, suggesting that ovarian development is controlled by a hypothalamic-pituitary-gonadal axis. Our results have provided new insights that advance our understanding of the molecular mechanism of C. nasus reproductive functions and will be useful for future breeding.

Tilapia is one of the fish that is widely cultivated in Indonesia. The obstacle to tilapia cultivation is high reproduction, which inhibits growth. An alternative to increase growth is by inhibiting gonad growth, so that feed energy is focused on somatic development. The aim of this research was to analyse the effect of velvet bean extract concentration on individual growth and gonad development of female tilapia fish and to determine the optimum concentration of velvet bean extract to increase growth and reduce reproductive activity in female tilapia fish. This study used a Completely Randomized Design (CRD) with the addition of various velvet bean extracts and compared with the control (without velvet bean extract). The use of velvet bean extract had a significant effect (p

Environmental pollutants cause health problems as well as affect living or non-living things in terrestrial and aquatic ecosystems. Many harmful substances, the use of which is increasing today, directly or indirectly cause deterioration in the quality of life of living things. Pollutions originating from water-primarily affect fish health. Negative effects are observed on the physiological, biochemical, and anatomical structures of fish feeding, migrating, and breeding in the aquatic environment due to pollutants. Zebrafish is an important model organism thanks to its development and easy reproduction. Many potential pollutants in the aquatic environment degrade the quality of water. Natural, industrial, domestic, etc. To the aquatic environment. Pollutants of organic or inorganic origin emitted from sources can cause toxic effects on fish. Pesticides, which are considered as one of these pollutants, are used to destroy the effects of harmful pests while causing death in living things, their negative effects on the reproductive system like many systems have been revealed. Heavy metals negatively affect the biological systems of fish by causing bioaccumulation by ingestion of fish mostly through respiration. Although endocrine-disrupting chemicals (EBC) affect different tissues and organs for generations, their effects on the reproductive system increase by affecting the hormonal system. Nanoparticles affect different biological systems as well as the reproductive system. In this article, the histological effects of environmental pollutants on zebrafish ( Danio reiro) reproductive organs and the reasons for choosing zebrafish as a model organism re-evaluated.

Climbing perch is one of the fish species that is in great demand by the public because of its distinctive taste, tasty and slightly fatty meat. A very important factor in ensuring the continuity of seed availability for cultivation activities depends on the readiness of the gonad-ripe parents, one of which is the female parent. Gonadal maturation can be increased by providing optimal feed for broodstock containing essential nutrients (protein, fat and vitamins). This study aims to analyze the effectiveness of adding zinc to the feed given and to analyze the optimal dose of zinc addition to the feed on the performance of the reproductive organs of female climbing perch. This study used a completely randomized design with 4 treatments and 3 replications. Treatment A commercial feed (CF)+0 mg zinc; B CF+100 mg Zinc; C CF+200 mg Zinc and D CF+Zinc 300 mg. The results of research on feeding zinc can improve the reproductive performance of climbing perch with a range of average levels of maturity and gonadal histology III-IV gonads.

The purpose of this study was to evaluate the fatty acid contents in various tissues (fillet, liver, gonad) of different ploidy (triploid and diploid) and sex (female and male) rainbow trout (Oncorhynchus mykiss) in the breeding season. In the study, diploid and triploid rainbow trouts belonging to the same age group (3+) were used. Fish were fed with commercial feed containing 45% crude protein and 20% crude fat until satiation. At the end of the 75-day study, biometric measurements of the fish were made and the tissues were stored in a deep freezer until biochemical and fatty acid analysis. The first finding of this study identified that ploidy (triploid and diploid) affects the biochemical and fatty acid composition of rainbow trout. The second major finding was that the polyunsaturated fatty acid values were higher and the saturated fatty acid values were lower in all tissues (especially female gonads) than other fatty acids. The results also indicate that the comparative among the biochemical and fatty acid composition of the fillet, liver, and gonad of rainbow trout is further illuminated by these data.

In the present study, 10 allotriploid (3nALT) and 10 allopentaploid (5nALP) six-month-old hybrid fish and two 3nALT and four 5nALP 40-month-old hybrid fish, which resulted by crossing female Russian sturgeon Acipenser gueldenstaedtii (Brandt and Ratzeberg, 1833) and male American paddlefish Polyodon spathula (Walbaum, 1792), were investigated. It was revealed that six-month-old 3nALT and 5nALP hybrids initially had “undifferentiated” gonads, while in the 40-month-old hybrids, only testes were observed in one case of 3nALT and one case of 5nALP hybrids. The testis of 3nALT hybrids was partially developed with spermatogonia, while the testis of one 5nALP hybrid was in the second developmental stage with low spermatogonia density. We could not determine gonad differentiation in any of the cases when the hybrid individuals had the W sex chromosome. We concluded that the gonad differentiation of these interfamilial hybrids follows a similar pattern to interspecific hybrids of different ploidy parent species of the family Acipenseridae, which is consistent with the classical Haldane’s rule. However, it cannot be excluded that the testis of this/these hybrid(s) may produce fertile sperm after sexual maturity, depending on additional genetic, hormonal and environmental factors, and further research is required for its evaluation.

ABSTRACT: The aim of the study was to explore the regulatory mechanism of differences in embryonic gonadal development between intergeneric distance hybrid offspring Mulard ducks and parent ducks. The morphological differences gonadal tissues of Muscovy ducks, Pekin ducks and Mulard ducks at 12.5-day embryonic age were observed by sectioning and hematoxylin-eosin (HE) staining. Then followed by transcriptome sequencing to screen for gonadal development-related differentially expressed circRNAs and mRNAs to construct a competitive endogenous RNA (ceRNA) regulatory network. Finally, qRT-PCR and luciferase reporter system were used to verify the sequencing data and targeting relationship of ceRNA pairs. The results showed that the seminiferous tubule lumen of Mulard ducks was not obvious, while there were obvious seminiferous tubules and tubular structures in testis of Pekin ducks and Muscovy ducks, with number and shape indicating maturity. There were 18 upregulated circRNAs and 16 downregulated circRNAs in Mulard ducks and Pekin ducks, respectively, and 39 upregulated circRNAs and 1 downregulated circRNA in Mulard ducks and Muscovy ducks, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis found that genes involves in dorso-ventral axis formation, for example, neurogenic locus notch homolog protein 1 (NOTCH1), were significantly enriched (P < 0.05). The novel_circ_0002265-gga-miR-122-5p-PAFAH1B2 regulatory network was constructed. The qRT-PCR results showed that the sequencing results were reliable. The dual-luciferase reporter assay showed that gga-miR-122-5p exists binding site of circ_0002265 and PAFAH1B2, indicating circ_0002265-gga-miR-122-5p-PAFAH1B2 targeting relationship. In summary, the embryonic gonadal development of intergeneric hybrid Mulard ducks may be regulated by differentially expressed circRNAs and genes, such as novel_circ_0000519, novel_circ_0003537, NOTCH1, FGFR2, PAFAH1B1, and PAFAH1B2, among which circ_0002265-gga-miR-122-5p-PAFAH1B2 may participate in the targeted regulation of gonadal development in Mulard ducks. The findings of this study are helpful for analyzing the mechanism of embryonic gonadal development differences in avians.

Rearing density directly impacts fish welfare, which, in turn, affects productivity in aquaculture. Previous studies have indicated that high-density rearing during sexual development in fish can induce stress, resulting in a tendency towards male-biased sex ratios in the populations. In recent years, research has defined the relevance of the interactions between the environment and epigenetics playing a key role in the final phenotype. However, the underlying epigenetic mechanisms of individuals exposed to confinement remain elucidated. By using zebrafish (Danio rerio), the DNA methylation promotor region and the gene expression patterns of six genes, namely dnmt1, cyp19a1a, dmrt1, cyp11c1, hsd17b1, and hsd11b2, involved in the DNA maintenance methylation, reproduction, and stress were assessed. Zebrafish larvae were subjected to two high-density conditions (9 and 66 fish/L) during two periods of overlapping sex differentiation of this species (7 to 18 and 18 to 45 days post-fertilization, dpf). Results showed a significant masculinization in the populations of fish subjected to high densities from 18 to 45 dpf. In adulthood, the dnmt1 gene was differentially hypomethylated in ovaries and its expression was significantly downregulated in the testes of fish exposed to high-density. Further, the cyp19a1a gene showed downregulation of gene expression in the ovaries of fish subjected to elevated density, as previously observed in other studies. We proposed dnmt1 as a potential testicular epimarker and the expression of ovarian cyp19a1a as a potential biomarker for predicting stress originated from high densities during the early stages of development. These findings highlight the importance of rearing densities by long-lasting effects in adulthood conveying cautions for stocking protocols in fish hatcheries. [ABSTRACT FROM AUTHOR]

Lipid profiles of the lipids from female gonads (LFG) and male gonads (LMG) of abalones (Haliotis discus hannai) were evaluated based on the analysis of phospholipid (PL) molecular species, PL class composition, fatty acid (FA) composition, and lipid class composition. These results suggested that lipids from abalone gonads were abundant in omega‐3 polyunsaturated FA (n − 3 PUFA, 14.42%–18.27% of total FAs) and PLs including phosphatidylcholine (PC, 21.26–47.85 mg g−1) and phosphatidylethanolamine (PE, 9.29–24.10 mg g−1). Furthermore, more than 60 molecular species of PC and PE were determined. Particularly, the molecular species containing n − 3 PUFA including eicosapentaenoic acid (EPA) constituted majority of PC and PE in LFG and LMG. By contrast, LFG contained more PC and PE species containing EPA. Considering the lipid profiles, abalone gonads are a potential source of PL‐form n − 3 PUFA. [ABSTRACT FROM AUTHOR]

Tilapia is one of the fish that is widely cultivated in Indonesia. The obstacle to tilapia cultivation is high reproduction, which inhibits growth. An alternative to increase growth is by inhibiting gonad growth, so that feed energy is focused on somatic development. The aim of this research was to analyse the effect of velvet bean extract concentration on individual growth and gonad development of female tilapia fish and to determine the optimum concentration of velvet bean extract to increase growth and reduce reproductive activity in female tilapia fish. This study used a Completely Randomized Design (CRD) with the addition of various velvet bean extracts and compared with the control (without velvet bean extract). The use of velvet bean extract had a significant effect (p<0.05) on growth parameters such as length, weight, fecundity and egg diameter. The best treatment was found in treatment 3 (velvet bean extract 5 ml.kg-1) which resulted in growth in individual length of 16.1 cm, individual weight of 89.43 g, fecundity of 2206 and egg diameter of 1.11 mm. In addition, the dose in this treatment may reduce the reproductive activity of tilapia. [ABSTRACT FROM AUTHOR]

Prior studies demonstrated that gonadal differentiation in the rice field frog, Hoplobatrachus rugulosus, was of an undifferentiated type since all individuals had ovaries at complete metamorphosis. However, the steroidogenic potential of the gonad is still unknown. In this study, H. rugulosus were obtained by stimulating fertilization in the laboratory under natural light and temperature conditions. The gonads were collected and their steroidogenic potential was evaluated by determining the expression level of messenger RNA (mRNA) encoding for cytochrome P450 17‐hydroxylase/C17–20 lyase (CYP17) and cytochrome P450 aromatase (CYP19) using quantitative real‐time RT‐PCR and the localization of CYP17 mRNA in tissues by in situ hybridization. The CYP17 mRNA levels in males at 4–11 weeks postmetamorphosis were higher than in female and intersex gonads. This corresponded to their localization in the gonadal tissues, where CYP17 signals were specifically detected in the Leydig cells of the testis at 5–16 weeks postmetamorphosis but was undetectable in all ovary samples. The CYP19 mRNA levels in females at 4–11 weeks postmetamorphosis was higher than in male and intersex gonads, which corresponded with gonadal development, indicating the potential steroidogenic function of the ovary. Based on the present results, the role of CYP17 and CYP19 mRNA in sex differentiation in H. rugulosus may occur after gonadal sex differentiation and the steroidogenic potential of the gonads exhibited a sexual dimorphic pattern. These results provide a crucial basis for further research on the developmental biology in anuran species. [ABSTRACT FROM AUTHOR]

Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because a wide range of environmental contaminants are known to cause endocrine disorders in humans and animals, in vivo tests are needed to identify such endocrine disrupting chemicals (EDCs) and to assess their biological effects. Despite the lack of a standardized guideline, the avian embryo has been shown to be a promising model system which responds sensitively to EDCs. After previous studies on the effects of estrogenic, antiestrogenic and androgenic substances, the present work focuses on the effects of in ovo exposure to p,p'-DDE, flutamide and cyproterone acetate (CPA) as antiandrogenic model compounds regarding gonadal sex differentiation and embryonic development of the domestic fowl (Gallus gallus domesticus). The substances were injected into the yolk of fertilized eggs on embryonic day one. On embryonic day 19 sex genotype and phenotype were determined, followed by gross morphological and histological examination of the gonads. Treatment with flutamide (0.5, 5, 50 mg/g egg), p,p'-DDE (0.5, 5, 50 mg/g egg) or CPA (0.2, 2, 20 mg/g egg) did not affect male or female gonad development, assessed by gonad surface area and cortex thickness in both sexes and by the percentage of seminiferous tubules in males as endpoints. This leads to the conclusion that antiandrogens do not affect sexual differentiation during embryonic development of G. gallus domesticus, reflecting that gonads are not target organs for androgens in birds. In ovo exposure to 2 and 20 mg CPA/g egg, however, resulted in significantly smaller embryos as displayed by shortened lengths of skull, ulna and tarsometatarsus. Although gonadal endpoints were not affected by antiandrogens, the embryo of G. gallus domesticus is shown to be a suitable test system for the identification of substance-related mortality and developmental delays. [ABSTRACT FROM AUTHOR]

It is difficult to predict the gonad weight and index of edible sea urchins from just their appearance. In this research, we attempted to develop a non-destructive method for evaluating the gonad weight and index of Strongylocentrotus nudus using a transmission-type near-infrared spectrometer, which is widely used for nondestructive evaluation of the internal quality of fruits and vegetables. Two hundred sixteen S. nudus samples were collected in the Pacific Ocean near Ishinomaki City and Onagawa Town, Miyagi Prefecture, in 2021 and 2022. The obtained near-infrared absorption spectra were analyzed by principal component analysis. The first principal component explained 90 % of the second derivative-processed spectra. A negative peak was observed in the first loading vector around 930 nm, which is known as the lipid absorption band. The partial least squares regression model using second derivative-processed absorption spectra successfully predicted gonad weight with a factor number of 4, correlation coefficient of 0.78, and standard error of 4.4 g. Similarly, for the gonad index, a partial least squares regression model using 4 factors showed a correlation coefficient of 0.76 and a standard error of 4.6 g/100 g. These results suggest that near-infrared spectroscopy can evaluate the gonad weight and index without harming or damaging live specimens. This is mainly due to measuring the lipids in the gonads. This method could be used for non-destructive, auto-sorting systems for wild and cultured sea urchins. [ABSTRACT FROM AUTHOR]

Hemicentrotus pulcherrimus is usually consumed in summer when the ovaries and testes are immature and tasty, and is not utilized from autumn to spring as a bitter compound, pulcherrimine accumulates in the ovaries. However, in the northern distribution edge (Tohoku and Hokkaido), it is not consumed because the ovaries are bitter nearly all year. Our previous studies suggested that the short palatable season in northern H. pulcherrimus is caused by a lower seawater temperature. To test this hypothesis, we reared H. pulcherrimus collected in Hokkaido at manipulated temperatures. Higher temperatures than the natural temperature at the collection site from August to March delayed gametogenesis and pulcherrimine accumulation, which usually begins in autumn. Temperature elevation during the spawning season (April) advanced the transition of mature ovaries to immature ovaries and led to the disappearance of the remaining pulcherrimine. Seawater temperature estimated using an ocean forecast system revealed that the warmer season, when the temperature exceeds 20 °C, is shorter where H. pulcherrimus is not consumed. We believe that the short palatable season of H. pulcherrimus in the northern edge of the distribution is due to the short summer season. Such H. pulcherrimus, however, can be improved by cultivation for several months at elevated temperatures. [ABSTRACT FROM AUTHOR]

Studies in humans and mice support a role for Makorin RING finger protein 3 (MKRN3) as an inhibitor of gonadotropin-releasing hormone (GnRH) secretion prepubertally, and its loss of function is the most common genetic cause of central precocious puberty in humans. Studies have shown that the gonads can synthesize neuropeptides and express MKRN3/Mkrn3 mRNA. Therefore, we aimed to investigate the spatiotemporal expression pattern of Mkrn3 in gonads during sexual development, and its potential regulation in the functional testicular compartments by gonadotropins. Mkrn3 mRNA was detected in testes and ovaries of wild-type mice at all ages evaluated, with a sexually dimorphic expression pattern between male and female gonads. Mkrn3 expression was highest peripubertally in the testes, whereas it was lower peripubertally than prepubertally in the ovaries. Mkrn3 is expressed primarily in the interstitial compartment of the testes but was also detected at low levels in the seminiferous tubules. In vitro studies demonstrated that Mkrn3 mRNA levels increased in human chorionic gonadotropin (hCG)–treated Leydig cell primary cultures. Acute administration of a GnRH agonist in adult mice increased Mkrn3 expression in testes, whereas inhibition of the hypothalamic–pituitary–gonadal axis by chronic administration of GnRH agonist had the opposite effect. Finally, we found that hCG increased Mkrn3 mRNA levels in a dose-dependent manner. Taken together, our developmental expression analyses, in vitro and in vivo studies show that Mkrn3 is expressed in the testes, predominantly in the interstitial compartment, and that Mkrn3 expression increases after puberty and is responsive to luteinizing hormone/hCG stimulation. [ABSTRACT FROM AUTHOR]