Immature Ovaries Research Articles

A novel approach for rapidly determining the reproductive status of walleye pollock (Gadus chalcogrammus) using Raman spectroscopy

Knowledge of the reproductive biology of fishes is essential for effective fisheries management. Information derived from an understanding of fish reproduction, such as size and age at maturity, is used in models to assess fish stocks and can affect estimates of important ecological processes such as recruitment, abundance, and trophic interactions. Common practices for determining the reproductive status of teleost fishes include macroscopic evaluation of gonads as well as histological analysis. However, macroscopic evaluation can be biased and histological analysis is time-consuming, resulting in limitations to spatial and temporal data availability. Here, we explore Raman spectroscopy of ovaries as a novel approach to rapidly determine the reproductive status of walleye pollock (Gadus chalcogrammus), a commercially and ecologically important species in the North Pacific. We used a two-stage partial least-squares (PLS) regression analysis followed by a linear discriminant analysis (LDA) to classify walleye pollock ovary samples as physiologically mature or immature and to subsequently predict their histologically-determined reproductive stage based on the Raman spectra. Biologically mature samples with visible yolk differentiated from mature and immature samples (non-yolked; 99% accuracy). Non-yolked ovaries that were physiologically mature (either mature non-developing or previously spawned) were further differentiated from physiologically immature ovaries (93% accuracy). In addition, detailed, histologically-determined reproductive stages of yolked samples also differentiated via Raman spectroscopy, but with reduced accuracy (79% - 86% accuracy). Our results indicate that accurate identification of maturity status and the reproductive staging of oocytes of walleye pollock based on spectral data from ovaries is possible. This can provide a fast and efficient way to increase the availability of a key component of reproductive data to inform fisheries research and management.

Population dynamics and reproductive features of the Amazon River prawn Macrobrachium amazonicum (Heller, 1862) in Neotropical reservoirs under drought events

Here, we describe population and reproductive dynamics of four populations of Macrobrachium amazonicum in reservoirs during drought events. Additionally, we analyze possible phenotypic changes in this species promoted by fish predation. Two populations had a large-size phenotype (with large body proportions and morphotypes in males) while a small-size phenotype (with reduced sizes and no morphotypes) was found in the two other populations. Overall, females were larger than males and there were varying sex ratios among the four studied populations. All populations had bimodal or polymodal patterns in their monthly size-class frequency, suggesting a seasonal influence and a potentially great capacity of these populations to adapt to adverse environmental conditions. No major changes were found in the patterns of sex ratio, recruitment, frequency of (larger) male morphotypes and female ovarian development stages during drought events. Macrobrachium amazonicum is a resilient species and undergoes continuous reproduction. Females with immature ovaries were predominant in all populations, performing multiple spawns and exhibiting rapid ovarian development cycles. In males, the initial morphotype (TC - translucent claw) was predominant in populations with a social hierarchy. Males of dominant morphotypes (GC1 and GC2 - green claw 1 and 2) use more energy to carry out and maintain metabolic processes, which could probably one of the explanations why their number in populations are limited. We did not find any clear evidence that fish predation affected phenotypes, suggesting that phenotypic plasticity could be more related to intrinsic factors, which would have to be further investigated.

Cyclic Variations of Ovarian Development, Hormones and Sex Related Genes of Rainbow Trout (Oncorhynchus mykiss) During Different Growth Stages

This study aimed to investigate the reproductive biology of female rainbow trout (Oncorhynchus mykiss). Mature female (n.80) rainbow trout from different reproductive phases were collected. Through a transmission electron microscope (TEM), it was feasible to examine the oocyte at several developmental stages, namely the perinucleolus stage, cortical alveoli stage, vitellogenic stage, mature stage, and postovulatory stage. Progesterone and estradiol levels were measured at their lowest during the immature and spent phases, while reaching their highest levels during the maturing and mature stages. The total amount of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) was greater in mature ovaries compared to immature and maturing ovaries. Gene transcripts related to the production of steroids, specifically star, cyp11a1, cyp17a1 and hsd3b were expressed at low levels during the immature stage and showed a significant rise during the mature stage. The ovarian gene expression patterns during oogenesis exhibited distinct dissimilarities. The fatty acid content, essential for the development of fish ovaries, and the sex steroid hormonal profile, which play a key role in regulating oogenesis, are particularly significant. These results will enhance our comprehension of the reproductive biology and sustainable management of rainbow trout in their natural environment.

Rainfall during the night can trigger non-migratory take-off behavior of the white-backed planthopper, Sogatella furcifera.

Take-off behavior is crucial to the overall success of insect migration. Although most high-altitude migratory flights commence with mass take-offs around dusk and dawn, little is known about nighttime take-off behavior. The take-off behavior of migratory Sogatella furcifera was investigated in field cages from 2017 to 2019. The species showed a bimodal take-off pattern at dusk and dawn on rainless nights, with mass flight at dusk more intense than dawn flight. However, a higher frequency of take-offs during the nighttime was observed on rainy nights, resulting in the absence of dawn take-offs. Most migratory take-off individuals at dusk and dawn landed on the cage top or the walls above 150cm, while non-migratory individuals that took off during the nighttime due to rainfall mainly landed on the cage walls below 150cm. Furthermore, it has been observed that migratory take-off individuals possess stronger sustained flight capabilities and exhibit more immature ovaries compared with non-migratory take-offs. These findings advance our understanding of the take-off behavior of S. furcifera and thus provide a basis for the accurate prediction and management of the migratory dynamics of this pest.

Vertical transmission and prevalence of white spot syndrome virus (WSSV) in the wild spawning population of the Indian white shrimp, Penaeus indicus

White spot disease, caused by white spot syndrome virus (WSSV), has historically been the most devastating disease in shrimp aquaculture industry across the world. The mode of virus transmission is the most crucial stage in the dynamics and management of virus infection. This study explored the mechanism of vertical transmission of WSSV in Indian white shrimp, Penaeus indicus, potential native species for domestication and genetic improvement, using quantitative real time PCR (q RT PCR), light and electron microscopy, and in situ hybridization. Wild brooders of P. indicus (n = 2576) were sampled along the South east coast of India, during 2016 to 2021. Of these ∼ 58 % of the brooders were positive for WSSV, and almost 50 % of infected wild brooders were at the various stages of reproductive maturation. WSSV-PCR positive brooders (n = 200) were analysed for vertical WSSV transmission. The q RT PCR studies of reproductive tissues revealed that 61 % (n = 13) of spermatophore, 54 % (n = 28) of immature ovaries and 48 % (n = 27) of ripe ovaries were infected with WSSV. The lowest level of infection was recorded in females with ripe ovaries (6.84 × 101 ± 9.79 × 100 ng genomic DNA) followed by fertilized eggs (1.59 × 102 ± 3.69 × 101 ng genomic DNA), and larvae (nauplius and zoea). The histology of gravid females with high WSSV copies showed pyknotic and karyorrhectic germinal vesicle with degenerated cortical rods. Conversely, the gravid females with low WSSV copies showed fully developed ovary without characteristic signs of WSSV infection. Transmission electron microscopic studies clearly established the presence of WSSV particles in both ovaries and spermatophores. When subjected to in situ hybridization, WSSV-specific signals were observed in connective tissues of spermatophore, although gravid ovary and fertilized eggs were failed to produce WSSV specific signals. The present study provides the first molecular and histological evidence for trans-ovarian vertical transmission of WSSV. Development of disease-free base population being the cornerstone and first step in establishing the breeding program, the present findings could be a basis for development of such programs.

Studies on Improving the Efficiency of Somatic Embryogenesis in Grapevine (Vitis vinifera L.) and Optimising Ethyl Methanesulfonate Treatment for Mutation Induction.

Somatic embryogenesis (SE) has many applications in grapevine biotechnology including micropropagation, eradicating viral infections from infected cultivars, mass production of hypocotyl explants for micrografting, as a continuous source for haploid and doubled haploid plants, and for germplasm conservation. It is so far the only pathway for the genetic modification of grapevines through transformation. The single-cell origin of somatic embryos makes them an ideal explant for mutation breeding as the resulting mutants will be chimera-free. In the present research, two combinations of plant growth regulators and different explants from flower buds at two stages of maturity were tested in regard to the efficiency of callusing and embryo formation from the callus produced in three white grape cultivars. Also, the treatment of somatic embryos with the chemical mutagen ethyl methanesulfonate (EMS) was optimised. Medium 2339 supplemented with β-naphthoxyacetic acid (5 μM) and 6-benzylaminopurine (BAP-9.0 μM) produced significantly more calluses than medium 2337 supplemented with 2,4-dichlorophenoxyacetic acid (4.5 µM) and BAP (8.9 µM) in all explants. The calluses produced on medium 2337 were harder and more granular and produced more SEs. Although the stage of the maturity of floral bud did not have a significant effect on the callusing of the explants, calluses produced from immature floral bud explants in the premeiotic stage produced significantly more SEs than those from more mature floral buds. Overall, immature ovaries and cut floral buds exposing the cut ends of filaments, style, etc., tested for the first time in grapevine SE, produced the highest percentage of embryogenic calluses. It is much more efficient to cut the floral bud and culture than previously reported explants such as anthers, ovaries, stigmas and styles during the short flowering period when the immature flower buds are available. When the somatic embryos of the three cultivars were incubated for one hour with 0.1% EMS, their germination was reduced by 50%; an ideal treatment considered to obtain a high frequency of mutations for screening. Our research findings will facilitate more efficient SE induction in grapevines and inducing mutations for improving individual traits without altering the genetic background of the cultivar.

Characterization and Expression of Cytochrome b5 Gene and Protein in Ovaries of Giant Tiger Shrimp Penaeus monodon

The full-length transcript of cytochrome b5 (PmCytb5) in the giant tiger shrimp (Penaeus monodon) was characterized. It was 1539 bp with an open reading frame (ORF) of 432 bp deducing to 143 amino acids. The deduced PmCytb5 protein contained predicted cytochrome b5-like heme/steroid binding domain (Cytb5, positions 17-91) and a transmembrane domain (positions 120-139). In non-ablated wild adults, PmCytb transcript was significantly increased in mature ovaries while it was earlier upregulated in late vitellogenic stage in eyestalk-ablated shrimp (P<0.05). Progesterone injection (0.1 μg/g) induced the expression of PmCytb5 at 48 hours post injection (hpi, P<0.05) but serotonin (50 μg/g) did not alter its expression (P>0.05) in domesticated adults. The cytoplasmic PmCytb5 protein was upregulated from immature ovaries in the early vitellogenic stage and comparably expressed in subsequent stages in non-ablated wild broodstock. In eyestalk-ablated wild broodstock, a similar expression profile was observed but its expression was further increased in late vitellogenic, and mature stages. The membrane PmCytb5 protein was upregulated in late vitellogenic and mature stages in the former but expressed at a similar level in different ovarian stages in eyestalk-ablated broodstock. Results suggested the important role of PmCytb5 in ovarian development of P. monodon.

Expression of Apoptosis-Related Genes in Cultured Ovarian Tissue of Mouse in Presence of Coenzyme Q10.

Oxidative stress affects the development of ovarian follicles during in vitro culture thus applying an antioxidant is necessary. The aim of this study was to investigate the effect of coenzyme Q10 (CoQ10) on the expression of apoptosis-related genes of mouse ovaries during in vitro culture. The immature mouse ovaries were cultured in the presence of 50 μM CoQ10 for 7 days. Histological examinations were performed and the 17 beta-estradiol concentration was measured on the seventh day of culture. The relative expression of Caspase 3, Bax, Bad, and Bcl 2 genes were investigated by real-time RT-PCR. The rates of normal follicles in the presence of CoQ10 was significantly increased compared to the control group. Also, in CoQ10-trated group a significant increase in the level of 17 beta-estradiol was seen compared to the control group. The mRNA expression of anti-apoptotic gene Bcl2 was significantly increased while the expression of pro-apoptotic genes (Caspase3, Bax and Bad) significantly declined in CoQ10 treated group compared to those of control group. The supplementation of the ovarian culture media with CoQ10 improved the follicular development through alteration in expression of apoptosis-related genes and stimulated the production of estradiol.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Accelerated of Sex Reversal use 17α-methyltestosterone Induced Female, Orange-Spotted Grouper <I>Epinephelus coioides</I>

Highlight Research Sex reversal for orange-spotted grouper Epinephelus coioides The application of 17α-methyltestosterone induce sex change The stability of sex change need more investigation Abstract The occurance of hermaphrodites in grouper fish causes a scarcity of male parents, so an alternative is needed to accelerate sexchange to male at a young age. The present study was expected to scrutinize the mechanisms of sex-change in fish in the early change process, and whether the testis converted from immature ovary using 17α-methyltestosterone (MT) would recover after the termination of MT treatment. MT-induced sex-change and 5-aza-2’-deoxycytidine (5-Aza) were connected as DNA methylation inhibitors to comprehend the alternation of gonadal soma cells. The orange-spotted groupers were used at the developmental ages and fed a diet containing MT at 50 mg/kg for three months and then a normal diet for a month. In the first week and second week fish injected with 5-Aza intraperitoneally during the MT-oral administration. Most of the fishes in the control group had immature ovaries, but all the females fed with MT, had immature spermatogenesis. However, one month after the withdrawal of MT treatment, the sex of the fish returned to female-like even though the fish have undergone MT-induced masculinization. This outcome demonstrates precocious sex-change from under yearling, orange-spotted grouper utilizing oral MT treatment is impermanent. All the females of 5-aza treatments showed no spermatogenic cells. In this study, lower growth rates were demonstrated by the MT-treated groups. The impact of this metabolic change was clear after the end of the hormone oral administration since the decreased growth of the groups treated for three months.

Histological characterization of sexual reproduction in the coral Pocillopora damicornis (Coelenterata: Scleractinia) from the Red Sea

The scleractinian coral is common along the Red Sea coast, and its reproductive mode and period of reproduction were assessed using histological preparations. the sexuality, and reproductive mod timing of reproductive of pocillopora damicornis from adjacent to the fringing reefs of the Ubhur Creek in the Red Sea, were assessed using a serial histological section. Sexual reproduction in pocillopora damicornis a shallow water hermatypic coral was studied from December 2011 to November 2012. pocillopora damicornis is a simultaneous hermaphrodite with ovary and testis in the project into the body cavity on the same mesentery. Sperm and eggs were usually released simultaneously from the same polyp. The onset of the reproductive period of pocillopora damicornis was found to be limited (April to May). In the number of eggs and testes observed in this period, the gonads were found in the polyps. The pocillopora damicornis egg size ranged from 49.80 µm (in March) to 125.0 µm (in May). Four stages were chosen, to reflect very immature ovaries, the early stages of oocyte development, ova near maturity, and mature ova, and also four distinct stages of sperm development were identified. The state of gonads development (eg. testis and eggs) was measured by a calibrated eyepiece micrometer of a compound light microscope. Zooxanthellae were presented in the mature oocytes in pocillopora damicornis. This study aimed to examine the reproduction mode and timing of pocillopora damicornis.

Transcriptome Analysis of Metapenaeus affinis Reveals Genes Involved in Gonadal Development

Metapenaeus affinis is a crustacean with important commercial value in the fishery of the South China Sea. Overfishing has resulted in the decline of the wild population and germplasm degradation. However, there is little background knowledge about its gonadal development, and there is a lack of research on the development of this species. To better understand the molecular regulatory mechanisms during gonadal development, here, we performed RNA-Seq on immature and mature ovaries and compared their transcriptomic signatures. 126,930,488 and 122,677,356 clean sequencing reads were obtained from the Illumina sequencing platform, respectively. 394 differentially expressed genes (DEGs) were identified, of which 136 were up-regulated, and 258 were down-regulated. Further analysis revealed rich transcriptional sequences, which have homology with genes related to reproduction and development. Expression patterns of COX, GPX, E3s, PCNA, STPK, and other genes were changed during ovarian development. Validation by qRT-PCR demonstrated the reliability of RNA-Seq. This study has made a significant contribution to the currently available sequence data of M. affinis and provided reference data for the development of genetic and breeding work.

Expression of voltage-gated Ca2+ channels, Insp3Rs, and RyRs in the immature mouse ovary

BackgroundThe postnatal mammalian ovary undergoes a series of changes to ensure the maturation of sufficient follicles to support ovulation and fecundation over the reproductive life. It is well known that intracellular [Ca2+]i signals are necessary for ovulation, fertilization, and egg activation. However, we lack detailed knowledge of the molecular identity, cellular distribution, and functional role of Ca2+ channels expressed during folliculogenesis. In the neonatal period, ovarian maturation is controlled by protein growth factors released from the oocyte and granulosa cells. Conversely, during the early infantile period, maturation becomes gonadotropin-dependent and is controlled by granulosa and theca cells. The significance of intracellular Ca2+ signaling in folliculogenesis is supported by the observation that mice lacking the expression of Ca2+/calmodulin-dependent kinase IV in granulosa cells suffer abnormal follicular development and impaired fertility.ResultsUsing immunofluorescence in frozen ovarian sections and confocal microscopy, we assessed the expression of high-voltage activated Ca2+ channel alpha subunits and InsP3 and ryanodine receptors in the postnatal period from 3 to 16 days. During the neonatal stage, oocytes from primordial and primary follicles show high expression of various Ca2+-selective channels, with granulosa and stroma cells expressing significantly less. These channels are likely involved in supporting Ca2+-dependent secretion of peptide growth factors. In contrast, during the early and late infantile periods, Ca2+ channel expression in the oocyte diminishes, increasing significantly in the granulosa and particularly in immature theca cells surrounding secondary follicles.ConclusionsThe developmental switch of Ca2+ channel expression from the oocytes to the perifollicular cells likely reflects the vanishing role of the oocytes once granulosa and theca cells take control of folliculogenesis in response to gonadotropins acting on their receptors.

Survey based on classification of PCOS using gene expression

Polycystic ovary syndrome (PCOS) is a complicated endocrine ailment affecting 5–10 % of girls of reproductive age. It is generally has complications such as irregular cycles, hirsutism and polycystic ovaries, collectively with a considerable incidence of insulin resistance. PCOS is taken into consideration a multifactorial ailment with numerous genetic, endocrine and environmental abnormalities. Eventhough, women who are suffered with PCOS are also have chances for cause of metabolic and cardiovascular illnesses and their associated diseases or disorders which are compared to the overall population. PCOS classification done on both phenotype and genotype, based on phenotype it is segmented into four phenotypes as A, B, C, D. This phenotype shows the association between hyperandrogenisms, structure or shape polycystic ovary and immature ovary formation. Phenotypes can be visualized through ultrasound images. Based on genotype, PCOS are categorized into three based on the hormonal factors. By analyze PCOS genetically we early diagnose the syndrome and take necessary remedial actions and also prevent from inheritance to next generations. In this paper, surveys the different genes involved in causes of PCOS and hormone factors associated with the PCOS.

Feasibility, Gross Postmortem Results and Participant Perception of Oblique Prefemoral Ovariectomy in Red Eared Sliders (Trachemys scripta elegans) During a Teaching Workshop

The purpose of the present report is to describe feasibility and gross postmortem results of oblique prefemoral ovariectomy in red-eared sliders (Trachemys scripta elegans) performed by veterinarians in a teaching environment. Sixteen red-eared sliders were included in a teaching workshop. The turtles were anesthetized and placed in dorsolateral recumbency at an oblique 45-degree angle by use of folded towels. After prefemoral access to the celom and placement of a retractor with elastic bands, the ipsilateral follicles were exteriorized via gentle maneuvering with cotton tip applicators and excised after application of titanium clips and cautery with bipolar radiosurgery. On 14 of the 16 chelonians (87.5%) surgery was successfully completed. Of the two chelonians that did not have the surgical procedure completed, one had marked celomitis with adhesion of the ovaries to the liver and one had immature ovaries. At the end of the surgical procedures all chelonians were euthanized and postmortem was performed. The 14 chelonians that had surgery completed had no evident remaining ovarian tissue on gross postmortem. A survey completed by the attendants nine months after the workshop showed that a minority of the respondents (1/17) found the procedure difficult, and that one of the seven respondents that performed the surgery after the workshop was not able to complete the procedure. This report indicated that oblique prefemoral ovariectomy in mature red-eared sliders can be effectively taught to veterinarians during a workshop, and that if the procedure is completed the chances of leaving ovarian remnants are low.

Detection of turner syndrome using hand X-ray using anchor based links segmentation method.

Turner Syndrome (TS) is a chromosomal disorder, wherein the female's growth is impacted. Immature ovaries, low stature, and heart abnormalities are a range of developmental and medical issues due to TS. The condition of TS might be detected prior to birth, throughout infancy or in the early years of life. The diagnosis of TS in girls with modest symptoms and indications is sometimes deferred until they reach adolescence or become young adults. This study presents an algorithm to segment the hand digital X-ray image in children with TS. In medical image and computer vision examination, image segmentation is demanding, and very crucial. Prevailing segmentation algorithms even now suffer from common segmentation issues including under-segmentation, over-segmentation, and spurious or non-closed edges, regardless of the several years of studies. In this paper, Anchor Based Link (ABL) segmentation approach is proposed to detect TS based on fourth Metacarpal bone from left hand X-ray images. The detection of TS is demonstrated based upon the comparison of proposed approach with existing watershed segmentation and Gaussian-Mixture-Model-based Hidden-Markov-Random-Field (GMM-HMRF) method. The proposed approach attains better segmentation based on the ratio of height and width of left fourth finger that is analyzed for normal children and children having TS with the help of edge pixel present in the metacarpal bone that has been segmented. The suggested method is verified on fifty (50) sample X-ray hand images of carpal bones, providing 0.60 ± 0.02 as an average Dice coefficient.

Juvenile hormone biosynthetic genes are critical for regulating reproductive diapause in the cabbage beetle

In insects, the juvenile hormone (JH) biosynthetic pathway regulates the in vivo JH titer. Thus, its downregulation potentially contributes to the lowering of JH titers typically observed in insects undergoing reproductive diapause, a developmental arrest at the adult stage. However, no systematic evidence has yet been presented to demonstrate the physiological and genetic roles of JH biosynthetic genes in reproductive diapause. In this work, we performed RNA interference (RNAi)-based reverse genetic analyses by targeting JH biosynthetic genes, followed by analysis of the reproductive diapause traits in Colaphellus bowringi, an economically important cabbage beetle. We identified a total of 22 genes encoding homologues of enzymes involved in the mevalonate pathway and the JH branch of JH biosynthesis in C. bowringi. Among these, 18 genes showed significant downregulation of their expression in the long day-induced diapausing females, compared to the short day-induced reproductive females. RNAi knockdown of almost any one of the 18 genes in reproductive females reduced the expression of the JH-responsive gene, Krüppel homolog1 (Kr-h1), indicating a lowered circulating JH. Most importantly, depleting transcripts of 3-hydroxy-3-methylglutaryl-CoA reductase 2 (HMGR2), farnesyl-pyrophosphate synthase 1 (FPPS1) and juvenile hormone acid methyltransferase 1 (JHAMT1) induced diapause-associated traits, including immature and inactive ovaries, large accumulations of lipids and adult burrowing behavior. Meanwhile, genes related to ovarian development, lipid accumulation and stress response showed expression patterns like those of diapausing females. RNAi-mediated diapause phenotypes could be reversed to reproductive phenotypes by application of methoprene, a JH receptor agonist. These results suggest that photoperiodic reproductive diapause in C. bowringi is triggered by transcriptional suppression of JH biosynthetic genes, with HMGR2, FPPS1 and JHAMT1 playing a critical role in this process. This work provides sufficient evidence to reveal the physiological roles of JH biosynthetic genes in reproductive diapause.

Effect of synthetic androgen treatment on the gonad of juvenile longtooth grouper (Epinephelus bruneus)

Commercially significant groupers are protogynous hermaphrodites. Since their sex change from female (ovary) to male (testis) occurred in a larger size and older age, capturing or maintaining males in the aquaculture farm is very difficult. In the present study, juvenile longthooth groupers (2+ years old) were implanted with two doses of 17alpha-methyltestosterone (MT) cholesterol pellet (2 mg or 5 mg MT kg-1 BW) for the induction of artificial sex reversal. Individuals were sampled at 30 and 80 days after treatment. All the control group fish had immature ovaries contained with primary oocytes and germ cells. Fish treated with MT for 30 days had sex-transitional gonad consisted of few primary oocytes and testicular tissues. By using immunohistochemistry, we identified the proliferating and apoptotic cells in the gonad of this sexual stage. After 80 days for MT treatment, gonads of all individuals were filled with germ cells at all stages of spermatogenesis, and the newly formed efferent duct contained active spermatozoa. Since sperm motility was confirmed, MT treatment successfully induced functional sex reversal in pre-pubertal longtooth grouper. This method may dramatically reduce the cost and time required for the production of longtooth grouper.

Papaya Vivipary: An Unusual Finding of “An Umbilical Cord”

Vivipary is not a rare finding in papaya fruit. However, this short communication describes the unusual germination of seedling within intra-ovarian ovary. The seedling is attached at two ends of the immature ovary: by radicle at one end, and by elongated tubular structure at the other end. The tubular structure, probably a hypocotyl, mimics an umbilical cord connecting the growing fetus with that of placenta in human embryonic development.

Accumulation of a bitter amino acid, pulcherrimine, in sea urchin ovaries and its relevance to the annual reproductive cycle

Hemicentrotus pulcherrimus in the Tohoku area is not utilized as a fishery product because the ovaries have a bitter taste almost all year. To discover the cause, we compared the annual reproductive cycles and ovarian accumulation of a bitter amino acid, pulcherrimine, in H. pulcherrimus collected at Mikuni (Fukui Prefecture), where it is fished in summer, and Iwaki (Fukushima Prefecture), where it is not utilized. At both sites, pulcherrimine increased in maturing ovaries as oogenesis proceeded from autumn to winter, decreased after spawning in spring, but remained in spent and immature ovaries for a few months. In Mikuni, pulcherrimine was scarcely detected in the ovaries for several months in summer. However, in Iwaki, late spawning delayed the disappearance of pulcherrimine in summer, and early initiation of oogenesis advanced the restart of pulcherrimine accumulation in autumn compared to Mikuni. Consequently, the period when the ovaries were palatable because of the absence of pulcherrimine during summer was short in Iwaki. The major cause of such short-term palatability could be the lower seawater temperature in the Tohoku area. Furthermore, pulcherrimine was never detected in other sea urchins, although a bitter taste was found in the mature ovaries of some species.