| 1. |
Tapas Chakraborty Sipra Mohapatra, Michiya Matsuyama, Yoshitaka Nagahama, Kohei Ohta., Sex lethal gene manipulates gonadal development of medaka, Oryzias latipes through estrogenic interventions. International journal of molecular sciences., International journal of molecular sciences., 2022.10. |
| 2. |
Tapas Chakraborty, Yume Yamamoto, Shoma Hanai, Mayumi Hirano, Sipra Mohapatra, Akihiko Yamaguchi, Tatsusuke Takeda, Michiya Matsuyama, Kohei Ohta. , Divulging the social sex change mechanism in a unique model system for studying the sexual plasticity of protogynous hermaphrodite fish, three bamboo leaf wrasse (Pseudolabrus sieboldi). , Frontiers in Marine Sciences, 2022.10. |
| 3. |
Sipra Mohapatra, Tapas Chakraborty, Genome Editing in Fish Reproduction, 2022.06. |
| 4. |
u Li, You Wu, Chenhua Zhao, Yiyang Miao, Jing Cai, Lingyun Song, Jing Wei, Tapas Chakraborty, Limin Wu, Deshou Wang, Linyan Zhou,, The role of StAR2 gene in testicular differentiation and spermatogenesis in Nile tilapia (Oreochromis niloticus), The Journal of Steroid Biochemistry and Molecular Biology, https://doi.org/10.1016/j.jsbmb.2021.105974, 2021.08. |
| 5. |
Yoshitaka Nagahama, Tapas Chakraborty, Bindhu Paul-Prasanth, Kohei Ohta, and Masaru Nakamura, Sex determination, gonadal sex differentiation, and plasticity in vertebrate species, Physiological review, 2021.06, A diverse array of sex determination (SD) mechanisms, encompassing environmental to genetic, have been found to exist among vertebrates, covering a spectrum from fixed SD mechanisms (mammals) to functional sex change in fishes (sequential hermaphroditic fishes). A major landmark in vertebrate SD was the discovery of the SRY gene in 1990. Since that time, many attempts to clone an SRY ortholog from nonmammalian vertebrates remained unsuccessful, until 2002, when DMY/dmrt1by was discovered as the SD gene of a small fish, medaka. Surprisingly, however, DMY/dmrt1by was found in only 2 species among more than 20 species of medaka, suggesting a large diversity of SD genes among vertebrates. Considerable progress has been made over the last 3 decades, such that it is now possible to formulate reasonable paradigms of how SD and gonadal sex differentiation may work in some model vertebrate species. This review outlines our current understanding of vertebrate SD and gonadal sex differentiation, with a focus on the molecular and cellular mechanisms involved. An impressive number of genes and factors have been discovered that play important roles in testicular and ovarian differentiation. An antagonism between the male and female pathway genes exists in gonads during both sex differentiation and, surprisingly, even as adults, suggesting that, in addition to sex-changing fishes, gonochoristic vertebrates including mice maintain some degree of gonadal sexual plasticity into adulthood. Importantly, a review of various SD mechanisms among vertebrates suggests that this is the ideal biological event that can make us understand the evolutionary conundrums underlying speciation and species diversity.. |
| 6. |
Sipra Mohapatra, Tapas Chakraborty, Sonoko Shimizu, Kayoko Ohta, Yoshitaka Nagahama, Kohei Ohta , Estrogen and estrogen receptors chauffeur the sex-biased autophagic action in liver, Cell death and Differentiation, 10.1038/s41418-020-0567-3, 10.1038/s41418-020-0567-3, 2020.06, Autophagy, or cellular self-digestion, is an essential cellular process imperative for energy homeostasis, development, differentiation, and survival. However, the intrinsic factors that bring about the sex-biased differences in liver autophagy are still unknown. In this work, we found that autophagic genes variably expresses in the steroidogenic tissues, mostly abundant in liver, and is influenced by the individual’s sexuality. Starvation-induced autophagy in a time-dependent female-dominated manner, and upon starvation, a strong gender responsive circulating steroid-HK2 relation was observed, which highlighted the importance of estrogen in autophagy regulation. This was further confirmed by the enhanced or suppressed autophagy upon estrogen addition (male) or blockage (female), respectively. In addition, we found that estrogen proved to be the common denominator between stress management, glucose metabolism, and autophagic action in female fish. To understand further, we used estrogen receptor (ER)α- and ER-β2-knockout (KO) medaka and found ER-specific differences in sex-biased autophagy. Interestingly, starvation resulted in significantly elevated mTOR transcription (compared with control) in male ERα-KO fish while HK2 and ULK activation was greatly decreased in both KO fish in a female oriented fashion. Later, ChIP analysis confirmed that, NRF2, an upstream regulator of mTOR, only binds to ERα, while both ERα and ERβ2 are effectively pulled down the HK2 and LC3. FIHC data show that, in both ER-KO fish, LC3 nuclear-cytoplasmic transport and its associated pathways involving SIRT1 and DOR were greatly affected. Cumulatively, our data suggest that, ERα-KO strongly affected the early autophagic initiation and altered the LC3 nuclear-cytoplasmic translocation, thereby influencing the sex-biased final autophagosome formation in medaka. Thus, existence of steroid responsive autophagy regulatory-switches and sex-biased steroid/steroid receptor availability influences the gender-skewed autophagy. Expectedly, this study may furnish newer appreciation for gender-specific medicine research and therapeutics.. |
| 7. |
Tapas Chakraborty, P. Gireesh Babu, Absar Alam, Aparna Chaudhari, GFP expressing bacterial biosensor to measure lead contamination in aquatic environment, Current Science, 94, 6, 800-805, 2008.03, A bacterial biosensor is reported that responds to Pb2+ in the range of 50-400 μM by expressing green fluorescence protein (GFP). The genetic element that senses Pb2+ includes the regulatory protein gene (PbrR) along with operator/promoter (PbrO/P) of the lead resistance operon from plasmid pMOL30. PbrO/P also controls the gfp reporter gene expression. Escherichia coli DH5α is the host organism. GFP response to induction by Pb2+ peaked at 250 μM. Decline in fluorescence beyond 250 μM was related to drop in copy number of the biosensor plasmid in the cells. A formula that estimates available Pb2+ concentration in test samples with 95% accuracy was derived by multiple regression of fluorescence and cell density values at various Pb2+ concentrations at 12 h growth. The biosensor was tested for co-inducibility by Cd2+, Zn2+ and Hg2+. Only Zn2+ showed mild induction at high concentrations and the highest fluorescence obtained was 8.5 times lower than that obtained with Pb2+. The induction method used here allows water collected from natural resources to be directly tested by using it to prepare the growth medium for the biosensor. This biosensor offers a simple and quick method for detection of available lead in the aquatic environment.. |
| 8. |
Tapas Chakraborty, Yoshinao Katsu, Lin Yan Zhou, Shinichi Miyagawa, Yoshitaka Nagahama, Taisen Iguchi, Estrogen receptors in medaka (Oryzias latipes) and estrogenic environmental contaminants
An in vitro-in vivo correlation, Journal of Steroid Biochemistry and Molecular Biology, 10.1016/j.jsbmb.2010.11.015, 123, 3-5, 115-121, 2011.02, In many vertebrates, estrogens are necessary to promote the growth and differentiation of the female reproductive system during development, and have important reproductive roles in both males and females. Medaka (Oryzias latipes) has three estrogen receptor (ER) subtypes, ERα, ERβ1 and ERβ2. To evaluate the three medaka ER (mER)-ligand interactions, we applied the ERE-luciferase reporter assay system to characterize each ER subtype. In this transient transfection assay system using mammalian cells, the mER proteins displayed estrogen-dependent activation. 17β-Estradiol (E 2) and op'-DDT showed high activation irrespective of ERs. Endosulfan also exhibited activation; with less/no transactivity measured using other pesticides, i.e., heptachlor, carbendazim, deltamethrin, acephate, dimethoate and amitraz. It was generally observed that ERβ2 had higher activation potential than ERα and ERβ1. To understand the molecular mechanism of estrogen action via ER, we also conducted E 2 treatment where we observed a trigger in ERβ2 expression upon E 2 exposure. The present data suggest that ERβ2 is essential for female gonad maintenance. The data were supported by induction of vitellogenin (VTG) mRNA in the liver and reduced VTG receptor mRNA expression in the gonad of both sexes. The present work will provide a basic tool allowing future studies to examine the receptor-ligand interactions and endocrine disrupting mechanisms, and also expands our knowledge of estrogen action on reproductive development in medaka.. |
| 9. |
Tapas Chakraborty, Yasushi Shibata, Lin Yan Zhou, Yoshinao Katsu, Taisen Iguchi, Yoshitaka Nagahama, Differential expression of three estrogen receptor subtype mRNAs in gonads and liver from embryos to adults of the medaka, Oryzias latipes, Molecular and Cellular Endocrinology, 10.1016/j.mce.2010.12.002, 333, 1, 47-54, 2011.02, In fish, estradiol-17β (E2) regulates various reproductive processes by acting through estrogen receptors (ERs). Here, we cloned three ER subtypes from medaka and examined their developmental expression in the gonads and liver of genetically females and males from embryos to adults. During embryogenesis, marked increases in the expression of ERβ2, but not either ERα or ERβ1, were found in genetically female embryos during sex differentiation. E2 treatment induced marked up-regulation of ERβ2 expression in genetically male embryos. In adult ovaries, ERα levels were high in follicles (granulosa cells) during oocyte growth. In the testis, ERβ1 expression exhibited a distinct peak at 10 days post hatching (dph). In the liver, very high levels of ERβ2 were found in both females and males throughout the sampling period with significantly higher levels in females during 30-50 dph. These findings suggest each action of E2 to be mediated by different types of ERs.. |
| 10. |
S. Mohapatra, T. Chakraborty, A. K. Prusty, P. Das, K. Paniprasad, K. N. Mohanta, Use of different microbial probiotics in the diet of rohu, Labeo rohita fingerlings
Effects on growth, nutrient digestibility and retention, digestive enzyme activities and intestinal microflora, Aquaculture Nutrition, 10.1111/j.1365-2095.2011.00866.x, 18, 1, 1-11, 2012.02, Six iso-nitrogenous (350g proteinkg -1) and iso-caloric (4100kcalkg -1) diets with or without probiotics supplementation namely T 1 (Basal feed (BF) without probiotics; control), T 2 (BF+Bacillus subtilis and Lactococcus lactis), T 3 (BF+L. lactis and Saccharomyces cerevisiae), T 4 (BF+B. subtilis and S. cerevisiae), T 5 (BF+B. subtilis, L. lactis and S. cerevisiae) and T 6 (BF+heat-killed bacteria of B. subtilis, L. lactis and S. cerevisiae) were fed to Labeo rohita fingerlings (6.0±0.06g) for 60days in triplicate tanks (30 fish per tank). In all probiotic-supplemented diets, the probiotic concentration was maintained at 10 11cfukg -1 feed. After 60days of culture, the fish fed combination of three probiotics at equal proportion (T 5) had higher (P0.05) feed conversion ratio over other treatment groups. Total heterotrophic bacterial population in intestine was drastically reduced on 15th and 30th days of sampling than the initial value (0day of sampling) for T 3, T 4 and T 5 groups. Except T 6, the gut colonization of respective probiotics, which were supplemented through the diets, was also increased up to 30days of culture of fish and thereafter remained constant.. |
| 11. |
Sipra Mohapatra, Tapas Chakraborty, Ashisa Kumar Prusty, Kundan Kumar, K. Pani Prasad, Kedar Nath Mohanta, Fenvalerate induced stress mitigation by dietary supplementation of multispecies probiotic mixture in a tropical freshwater fish, Labeo rohita (Hamilton), Pesticide Biochemistry and Physiology, 10.1016/j.pestbp.2012.06.006, 104, 1, 28-37, 2012.09, Five experimental diets with various combinations of probiotics, namely T1 & T6 (basal feed (BF) without probiotics), T2 & T7 (BF+Bacillus subtilis+Lactococcus lactis), T3 & T8 (BF+L. lactis+Saccharomyces cerevisiae), T4 & T9(BF+B. subtilis+S. cerevisiae) and T5 & T10 (BF+B. subtilis+L. lactis+S. cerevisiae) were fed to Labeo rohita fingerlings for 30days. Treatment groups T1, T2, T3, T4 and T5 were exposed to Fenvalerate, at a concentration of 1.79μgL -1. The SOD and CAT activity was significantly affected (P |
| 12. |
Linyan Zhou, Tapas Charkraborty, Xiangguo Yu, Limin Wu, Gang Liu, Sipra Mohapatra, Deshou Wang, Yoshitaka Nagahama, R-spondins are involved in the ovarian differentiation in a teleost, medaka (Oryzias latipes), BMC Developmental Biology, 10.1186/1471-213X-12-36, 12, 2012.12, Background: In mammals, R-spondin (Rspo), an activator of the Wnt/β-catenin signaling pathway, has been shown to be involved in ovarian differentiation. However, the role of the Rspo/Wnt/β-catenin signaling pathway in fish gonads is still unknown. Results: In the present study, full-length cDNAs of Rspo1, 2 and 3 were cloned from the gonads of medaka (Oryzias latipes). The deduced amino acid sequences of mRspo1-3 were shown to have a similar structural organization. Phylogenetic analysis showed that Rspo1, 2 and 3 were specifically clustered into three distinct clads. Tissue distribution revealed that three Rspo genes were abundantly expressed in the brain and ovary. Real-time PCR analysis around hatching (S33-5dah) demonstrated that three Rspo genes were specifically enhanced in female gonads from S38. In situ hybridization (ISH) analysis demonstrated that three Rspo genes were expressed in the germ cell in ovary, but not in testis. Fluorescence multi-color ISH showed that Rspo1 was expressed in both somatic cells and germ cells at 10dah. Exposure to ethinylestradiol (EE2) in XY individuals for one week dramatically enhanced the expression of three Rspo genes both at 0dah and in adulthood. Conclusions: These results suggest that the Rspo-activating signaling pathway is involved in the ovarian differentiation and maintenance in medaka.. |
| 13. |
S. Mohapatra, T. Chakraborty, V. Kumar, G. Deboeck, K. N. Mohanta, Aquaculture and stress management
A review of probiotic intervention, Journal of Animal Physiology and Animal Nutrition, 10.1111/j.1439-0396.2012.01301.x, 97, 3, 405-430, 2013.06, To meet the ever-increasing demand for animal protein, aquaculture continuously requires new techniques to increase the production yield. However, with every step towards intensification of aquaculture practices, there is an increase in stress level on the animal as well as on the environment. Feeding practices in aqua farming usually plays an important role, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice among the fish and shrimp culturists. Probiotics, also known as 'bio-friendly agents', such as LAB (Lactobacillus), yeasts and Bacillus sp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are non-pathogenic and non-toxic micro-organisms, having no undesirable side effects when administered to aquatic organisms. Probiotics are also known to play an important role in developing innate immunity among the fishes, and hence help them to fight against any pathogenic bacterias as well as against environmental stressors. The present review is a brief but informative compilation of the different essential and desirable traits of probiotics, their mode of action and their useful effects on fishes. The review also highlights the role of probiotics in helping the fishes to combat against the different physical, chemical and biological stress.. |
| 14. |
Xiangguo Yu, Limin Wu, Lang Xie, Shijie Yang, Tapas Charkraborty, Hongjuan Shi, Deshou Wang, Linyan Zhou, Characterization of two paralogous StAR genes in a teleost, Nile tilapia (Oreochromis niloticus), Molecular and Cellular Endocrinology, 10.1016/j.mce.2014.05.013, 392, 1-2, 152-162, 2014.01, Steroidogenic acute regulatory protein (StAR) transports cholesterol, the substrate for steroid synthesis, to the inner membranes of mitochondria. It is well known that estrogen is essential for female sex determination/differentiation in fish. However, no reports showed that the conventional StAR, which was supposed to be essential for estrogen production, was expressed in female gonads during the critical timing of sex determination/differentiation. In this study, two different StAR isoforms, named as StAR1 and StAR2, were characterized from the gonads of Nile tilapia (Oreochromis niloticus). Phylogenetic and synteny analysis revealed that two StAR genes existed in teleosts, Xenopus and chicken indicating that the duplication event occurred before the divergence of teleosts and tetrapods. Real-time PCR revealed that StAR1 was dominantly expressed in the testis, head kidney and kidney; while StAR2 was expressed exclusively in the gonads. In situ hybridization and immunohistochemistry demonstrated that StAR1 was expressed in the interrenal cells of the head kidney and Leydig cells of the testis; while StAR2 was expressed in the Leydig cells of the testis and the interstitial cells of the ovary. Ontogenic analysis demonstrated that StAR2 was expressed abundantly from 5. days after hatching (dah) in the somatic cells in XX gonads, whereas in XY gonads, both StARs could be detected from 30. dah until adulthood. Intraperitoneal injection of human chorionic gonadotropin experiments showed that expression of StAR1 and 2 was significantly elevated at 8. h and persisted until 24. h after injection in the testis. Taken together, our data suggested that StAR1 is likely to be required for cortisol production in the head kidney, and StAR2 is probably involved in estrogen production during early sex differentiation in XX gonads. In contrast, both StARs might be required for androgen production in testes. For the first time, our data demonstrated that two fish StARs might be involved in steroidogenesis in a tissue and developmental stage dependent manner.. |
| 15. |
Sipra Mohapatra, Tapas Chakraborty, Ashisa K. Prusty, Kurchetti PaniPrasad, Kedar N. Mohanta, Beneficial effects of dietary probiotics mixture on hemato-immunology and cell apoptosis of Labeo rohita fingerlings reared at higher water temperatures, PloS one, 10.1371/journal.pone.0100929, 9, 6, 2014.06, Probiotics play an important role in growth increment, immune enhancement and stress mitigation in fish. Increasing temperature is a major concern in present aquaculture practices as it markedly deteriorates the health condition and reduces the growth in fish. In order to explore the possibilities of using probiotics as a counter measure for temperature associated problems, a 30 days feeding trial was conducted to study the hemato-immunological and apoptosis response of Labeo rohita (8.3±0.4 g) reared at different water temperatures, fed with or without dietary supplementation of a probiotic mixture (PM) consisting of Bacillus subtilis, Lactococcus lactis and Saccharomyces cerevisiae) (1011 cfu kg-1). Three hundred and sixty fish were randomly distributed into eight treatment groups in triplicates, namely, T1(28°C+BF(Basal feed)+PM), T2(31°C+BF+PM), T3(34°C+BF+PM), T4(37°C+BF+PM), T5(28°C+BF), T6(31°C+BF), T7(34°C+BF) and T8(37uC+BF). A significant increase (P |
| 16. |
Sipra Mohapatra, Tapas Chakraborty, Ashisa Kumar Prusty, Kurucheti Pani Prasad, Kedar Nath Mohanta, Dietary Multispecies Probiotic Supplementation Enhances the Immunohematological Responses and Reduces Mortality by Aeromonas hydrophila in Labeo rohita Fingerlings, Journal of the World Aquaculture Society, 10.1111/jwas.12144, 45, 5, 532-544, 2014.10, A study was conducted to determine the immunomodulatory effect of probiotic mixture on the nonspecific immune response and disease resistance of Labeo rohita. Fish were fed with six different test diets with or without probiotics, namely, T1 (basal feed [BF] without probiotics), T2 (BF+Bacillus subtilis [BS]+Lactococcus lactis [LL]), T3 (BF+LL+Saccharomyces cerevisiae [SC]), T4 (BF+BS+SC), T5 (BF+BS+LL+SC), and T6 (BF+heat-killed bacteria of BS+LL+SC). During the prechallenge period, significantly higher (P |
| 17. |
Sipra Mohapatra, Tapas Chakraborty, Shinichi Miyagawa, Linyan Zhou, Kohei Ohta, Taisen Iguchi, Yoshitaka Nagahama, Steroid responsive regulation of IFNγ2 alternative splicing and its possible role in germ cell proliferation in medaka, Molecular and Cellular Endocrinology, 10.1016/j.mce.2014.10.012, 400, 61-70, 2015.01, Interferon gamma (. IFNγ) is an active player in estrogen dependent immuno-regulation of fish. The present work was aimed to characterize the alternatively spliced isoforms of IFNγ2 in the gonadal sex development in medaka. Phylogenetic analysis demonstrated that IFNγ2a and 2b were clustered with fish specific interferon gamma. Our in vitro promoter and mini-genome analysis data confirmed that alternative splicing of IFNγ2 is regulated by estrogens and androgens. Tissue distribution, quantitative PCR and ISH data demonstrated ubiquitous expression of IFNγ2a, while IFNγ2b was only expressed predominantly in female germ cells than males. This was further confirmed by germ cell specific GFP signals in the IFNγ2b-GFP over-expressed embryos and specific induction of IFNγ2b expression in the BrdU positive cells. All together our data suggest that steroid responsive alternatively spliced IFNγ2b isoforms might have some indirect roles in germ cell proliferation and thus can be an important candidate for immuno-reproductive interaction studies.. |
| 18. |
Yongxiu Qiu, Shaohua Sun, Tapas Charkraborty, Limin Wu, Lina Sun, Jing Wei, Yoshitaka Nagahama, Deshou Wang, Linyan Zhou, Figla favors ovarian differentiation by antagonizing spermatogenesis in a teleosts, Nile tilapia (Oreochromis niloticus), PloS one, 10.1371/journal.pone.0123900, 10, 4, 2015.04, Figla (factor in the germ line, alpha), a female germ cell-specific transcription factor, had been shown to activate genetic hierarchies in oocytes. The ectopic expression of Figla was known to repress spermatogenesis-associated genes in male mice. However, the potential role of Figla in other vertebrates remains elusive. The present work was aimed to identify and characterize the functional relevance of Figla in the ovarian development of Nile tilapia (Oreochromis niloticus). Tissue distribution and ontogeny analysis revealed that tilapia Figla gene was dominantly expressed in the ovary from 30 days after hatching. Immunohistochemistry analysis also demonstrated that Figla was expressed in the cytoplasm of early primary oocytes. Intriguingly, over-expression of Figla in XY fish resulted in the disruption of spermatogenesis along with the depletion of meiotic spermatocytes and spermatids in testis. Dramatic decline of sycp3 (synaptonemal complex protein 3) and prm (protamine) expression indicates that meiotic spermatocytes and mature sperm production are impaired. Even though Sertoli cell (dmrt1) and Leydig cell (star and cyp17a1) marker genes remained unaffected, hsd3b1 expression and 11-KT production were enhanced in Figla-transgene testis. Taken together, our data suggest that fish Figla might play an essential role in the ovarian development by antagonizing spermatogenesis.. |
| 19. |
Sipra Mohapatra, Tapas Chakraborty, Sonoko Shimizu, Shintaro Urasaki, Takahiro Matsubara, Yoshitaka Nagahama, Kohei Ohta, Starvation beneficially influences the liver physiology and nutrient metabolism in Edwardsiella tarda infected red sea bream (Pagrus major), Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology, 10.1016/j.cbpa.2015.07.003, 189, 1-10, 2015.11, Dietary compromises, especially food restrictions, possess species-specific effects on the health status and infection control in several organisms, including fish. To understand the starvation-mediated physiological responses in Edwardsiella tarda infected red sea bream, especially in the liver, we performed a 20-day starvation experiment using 4 treatment (2 fed and 2 starved) groups, namely, fed-placebo, starved-placebo, fed-infected, and starved-infected, wherein bacterial exposure was done on the 11th day. In the present study, the starved groups showed reduced hepatosomatic index and drastic depletion in glycogen storage and vacuole formation. The fed-infected fish showed significant (P |
| 20. |
Linyan Zhou, Tapas Charkraborty, Qian Zhou, Sipra Mohapatra, Yoshitaka Nagahama, Yueguang Zhang, Rspo1-activated signalling molecules are sufficient to induce ovarian differentiation in XY medaka (Oryzias latipes), Scientific reports, 10.1038/srep19543, 6, 2016.01, In contrast to our understanding of testicular differentiation, ovarian differentiation is less well understood in vertebrates. In mammals, R-spondin1 (Rspo1), an activator of Wnt/β-catenin signaling pathway, is located upstream of the female sex determination pathway. However, the functions of Rspo1 in ovarian differentiation remain unclear in non-mammalian species. In order to elucidate the detailed functions of Rspo/Wnt signaling pathway in fish sex determination/differentiation, the ectopic expression of the Rspo1 gene was performed in XY medaka (Oryzias latipes). The results obtained demonstrated that the gain of Rspo1 function induced femininity in XY fish. The overexpression of Rspo1 enhanced Wnt4b and β-catenin transcription, and completely suppressed the expression of male-biased genes (Dmy, Gsdf, Sox9a2 and Dmrt1) as well as testicular differentiation. Gonadal reprograming of Rspo1-over-expressed-XY (Rspo1-OV-XY) fish, induced the production of female-biased genes (Cyp19a1a and Foxl2), estradiol-17β production and further female type secondary sexuality. Moreover, Rspo1-OV-XY females were fertile and produced successive generations. Promoter analyses showed that Rspo1 transcription was directly regulated by DM domain genes (Dmy, the sex-determining gene, and Dmrt1) and remained unresponsive to Foxl2. Taken together, our results strongly suggest that Rspo1 is sufficient to activate ovarian development and plays a decisive role in the ovarian differentiation in medaka.. |
| 21. |
Tapas Chakraborty, Lin Yan Zhou, Aparna Chaudhari, Taisen Iguchi, Y. Nagahama, Dmy initiates masculinity by altering Gsdf/Sox9a2/Rspo1 expression in medaka (Oryzias latipes), Scientific reports, 10.1038/srep19480, 6, 2016.01, Despite identification of several sex-determining genes in non-mammalian vertebrates, their detailed molecular cascades of sex determination/differentiation are not known. Here, we used a novel RNAi to characterise the molecular mechanism of Dmy (the sex-determining gene of medaka)-mediated masculinity in XY fish. Dmy knockdown (Dmy-KD) suppressed male pathway (Gsdf, Sox9a2, etc.) and favoured female cascade (Rspo1, etc.) in embryonic XY gonads, resulting in a fertile male-to-female sex-reversal. Gsdf, Sox9a2, and Rspo1 directly interacted with Dmy, and co-injection of Gsdf and Sox9a2 re-established masculinity in XY-Dmy-KD transgenics, insinuating that Dmy initiates masculinity by stimulating and suppressing Gsdf/Sox9a2 and Rspo1 expression, respectively. Gonadal expression of Wt1a starts prior to Dmy and didn't change upon Dmy-KD. Furthermore, Wt1a stimulated the promoter activity of Dmy, suggesting Wt1a as a regulator of Dmy. These findings provide new insights into the role of vertebrate sex-determining genes associated with the molecular interplay between the male and female pathways.. |
| 22. |
Linyan Zhou, Feng Luo, Xuelian Fang, Tapas Charkraborty, Limin Wu, Jing Wei, Deshou Wang, Blockage of progestin physiology disrupts ovarian differentiation in XX Nile tilapia (Oreochromis niloticus), Biochemical and Biophysical Research Communications, 10.1016/j.bbrc.2016.03.045, 473, 1, 29-34, 2016.04, Previous studies indicated that maturation inducing hormone, 17α, 20β-Dihydroxy-4-pregnen-3-one (DHP), probably through nuclear progestin receptor (Pgr), might be involved in spermatogenesis and oogenesis in fish. To further elucidate DHP actions in teleostean ovarian differentiation, we analyzed the expression of pgr in the ovary of Nile tilapia (Oreochromis niloticus), and performed RU486 (a synthetic Pgr antagonist) treatment in XX fish from 5 days after hatching (dah) to 120dah. Tilapia Pgr was abundantly expressed in the follicular cells surrounding oocytes at 30 and 90dah. Continuous RU486 treatment led to the blockage of oogenesis and masculinization of somatic cells in XX fish. Termination of RU486 treatment and maintenance in normal condition resulted in testicular differentiation, and estrogen compensation in RU486-treated XX fish successfully restored oogenesis. In RU486-treated XX fish, transcript levels of female dominant genes were significantly reduced, while male-biased genes were evidently augmented. Meanwhile, both germ cell mitotic and meiotic markers were substantially reduced. Consistently, estrogen production levels were significantly declined in RU486-treated XX fish. Taken together, our data further proved that DHP, possibly through Pgr, might be essential in the ovarian differentiation and estrogen production in fish.. |
| 23. |
Sipra Mohapatra, Tapas Chakraborty, Mohammad Ali Noman Reza, Sonoko Shimizu, Takahiro Matsubara, Kohei Ohta, Short-term starvation and realimentation helps stave off Edwardsiella tarda infection in red sea bream (Pagrus major), Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology, 10.1016/j.cbpb.2017.01.009, 206, 42-53, 2017.04, Dietary regime modifications have been an integral part of health and healing practices throughout the animal kingdom. Thus, to assess the effects of periodic starvation and refeeding schedule on the physiological and immunological perturbations in Edwardsiella tarda infected red sea bream, we conducted a 20 day experiment using 4 treatment groups, namely, pre-fed placebo (PFP); pre-starved placebo (PSP); pre-fed infected (PFI); and pre-starved infected (PSI), wherein a 5 h E. tarda infection was done on the 11th day. In the present investigation, the pre-starved groups showed significant (P |
| 24. |
Tapas Chakraborty, Sipra Mohapatra, Megumi Tobayama, Kayoko Ohta, Yong Woon Ryu, Yukinori Kazeto, Kohei Ohta, Linyan Zhou, Yoshitaka Nagahama, Takahiro Matsubara, Hatching enzymes disrupt aberrant gonadal degeneration by the autophagy/apoptosis cell fate decision, Scientific reports, 10.1038/s41598-017-03314-7, 7, 1, 2017.12, Environmental stressors, gonadal degenerative diseases and tumour development can significantly alter the oocyte physiology, and species fertility and fitness. To expand the molecular understanding about oocyte degradation, we isolated several spliced variants of Japanese anchovy hatching enzymes (AcHEs; ovastacin homologue) 1 and 2, and analysed their potential in oocyte sustenance. Particularly, AcHE1b, an ovary-specific, steroid-regulated, methylation-dependent, stress-responsive isoform, was neofunctionalized to regulate autophagic oocyte degeneration. AcHE1a and 2 triggered apoptotic degeneration in vitellogenic and mature oocytes, respectively. Progesterone, starvation, and high temperature elevated the total degenerating oocyte population and AcHE1b transcription by hyper-demethylation. Overexpression, knockdown and intracellular zinc ion chelation study confirmed the functional significance of AcHE1b in autophagy induction, possibly to mitigate the stress effects in fish, via ion-homeostasis. Our finding chronicles the importance of AcHEs in stress-influenced apoptosis/autophagy cell fate decision and may prove significant in reproductive failure assessments, gonadal health maintenance and ovarian degenerative disease therapy.. |
| 25. |
Shaohua Sun, Jing Cai, Wenjing Tao, Limin Wu, Chakraborty Tapas, Linyan Zhou, Deshou Wang, Comparative transcriptome profiling and characterization of gene expression for ovarian differentiation under RU486 treatment, General and Comparative Endocrinology, 10.1016/j.ygcen.2018.03.005, 261, 166-173, 2018.05, 17α, 20β-dihydroxypregn-4-en-3-one (17α, 20β-DP, DHP), a teleost specific biologically active progestin, has been proved to play a critical role in oocytes maturation, ovulation and spermiation. RU486 (Mifepristone, an antagonist of progestin receptor) has been applied in contraceptives, abortion and hormone therapy in clinical medicine. To get further insights into the molecular mechanisms of nuclear progestin receptor (Pgr) activated ovarian differentiation and maintenance, we conducted comparative gonadal transcriptome analysis, and investigated histological and transcriptional differences using 4 months after hatching (mah) RU486-treated XX and control XX/XY Nile tilapia (Oreochromis niloticus). DESeq analysis identified 7148 DEGs (differentially expressed genes) between RU486-treated and control XX gonads, while merely 442 DEGs were screened between the gonads of RU486-treated XX and control XY fish highlighting that RU486 treatment set forwards masculinity in XX fish. Comprehensive analysis of gene hierarchical clustering revealed that RU486 treatment in XX fish resulted in robust changes of gene expression profiles. In comparison with XX group, female-dominant genes were significantly repressed in RU486 treated XX fish gonads. Moreover, most parts of down-regulated genes in wild type female were evidently up-regulated genes in RU486-treated XX fish gonads. Comparing with control XY group, the majority of male-dominant genes represent a high level of expression. However, RU486-treatment led to an up-regulation of a cluster genes specifically which showed relative lower expression in both control XX and XY group. RU486-treatment mediated global changes of gene expression profiles in steroidogenesis, germ cell differentiation and follicular cell trans-differentiation were verified by quantitative PCR. Both morphological and immunohistochemistry results further proved that RU486 treatment initiates testicular-like gonads development in XX fish via simultaneously enhancing the male responsive genes and suppressing the female-dominant genes. Moreover, RU486 treatment caused significant decline of fshr, lhr and increase of ars. Taken together, our data confirms blocking of DHP physiology by RU486 treatment induces masculinization in XX gonad preferably via repressing of gonadotropin physiology, germ cell differentiation and promoting follicular trans-differentiation in teleosts.. |
| 26. |
Mohammad Ali Noman Reza, Sipra Mohapatra, Sonoko Shimizu, Shin Ichi Kitamura, Shogo Harakawa, Hidemasa Kawakami, Kei Nakayama, Eitaro Sawayama, Takahiro Matsubara, Kohei Ohta, Tapas Chakraborty, Molecular cloning, characterization and expression analysis of complement components in red sea bream (Pagrus major) after Edwardsiella tarda and red sea bream Iridovirus (RSIV) challenge, Fish and Shellfish Immunology, 10.1016/j.fsi.2018.08.027, 82, 286-295, 2018.11, The complement system plays an important role in immune regulation and acts as the first line of defense against any pathogenic attack. To comprehend the red sea bream (Pagrus major) immune response, three complement genes, namely, pmC1r, pmMASP and pmC3, belonging to the classical, lectin and alternative complement cascade, respectively, were identified and characterized. pmC1r, pmMASP, and pmC3 were comprised of 2535, 3352, and 5735 base mRNA which encodes 732, 1029 and 1677 aa putative proteins, respectively. Phylogenetically, all the three studied genes clustered with their corresponding homologous clade. Tissue distribution and cellular localization data demonstrated a very high prevalence of all the three genes in the liver. Both bacterial and viral infection resulted in significant transcriptional alterations in all three genes in the liver with respect to their vehicle control counterparts. Specifically, bacterial challenge affected the pmMASP and pmC3 expression, while the viral infection resulted in pmC1r and pmC3 mRNA activation. Altogether, our data demonstrate the ability of pmC1r, pmMASP and pmC3 in bringing about an immune response against any pathogenic encroachment, and thus activating, not only one, but all the three complement pathways, in red sea bream.. |
| 27. |
T. Chakraborty, S. Mohapatra, Lin Yan Zhou, K. Ohta, Takahiro Matsubara, Taisen Iguchi, Yoshitaka Nagahama, Estrogen Receptor β2 Oversees Germ Cell Maintenance and Gonadal Sex Differentiation in Medaka, Oryzias latipes, Stem Cell Reports, 10.1016/j.stemcr.2019.07.013, 13, 2, 419-433, 2019.08, In vertebrates, estrogen receptors are essential for estrogen-associated early gonadal sex development. Our previous studies revealed sexual dimorphic expression of estrogen receptor β2 (ERβ2) during embryogenesis of medaka, and here we investigated the functional importance of ERβ2 in female gonad development and maintenance using a transgenerational ERβ2-knockdown (ERβ2-KD) line and ERβ2-null mutants. We found that ERβ2 reduction favored male-biased gene transcription, suppressed female-responsive gene expression, and affected SDF1a and CXCR4b co-assisted chemotactic primordial germ cell (PGC) migration. Co-overexpression of SDF1a and CXXR4b restored the ERβ2-KD/KO associated PGC mismigration. Further analysis confirmed that curtailment of ERβ2 increased intracellular Ca<sup>2+</sup> concentration, disrupted intra- and extracellular calcium homeostasis, and instigated autophagic germ cell degradation and germ cell loss, which in some cases ultimately affected the XX female sexual development. This study is expected improve our understanding of germ cell maintenance and sex spectrum, and hence open new avenues for reproductive disorder management. In this article, Chakraborty et al. find that estrogen receptor β2 (ERβ2) plays multifaceted crucial roles in medaka gonadal development and sexuality. ERβ2 predominantly expresses in germ cells, influences the SDF1/CXCR4 chemotaxis, PGC migration, and death, and regulates germ cell proliferation and various sex-biased gene transcriptions that are essential for gonadal sex assignment and maintenance.. |
| 28. |
Jing Cai, Lu Li, Lingyun Song, Lang Xie, Feng Luo, Shaohua Sun, Tapas Chakraborty, Linyan Zhou, Deshou Wang, Effects of long term antiprogestine mifepristone (RU486) exposure on sexually dimorphic lncRNA expression and gonadal masculinization in Nile tilapia (Oreochromis niloticus), Aquatic Toxicology, 10.1016/j.aquatox.2019.105289, 215, 2019.10, Mifepristone (RU486), a clinical abortion agent and potential endocrine disruptor, binds to progestin and glucocorticoid receptors and has multiple functional importance in reproductive physiology. A long-term exposure of RU486 resulted in masculinization of female fish, however, the epigenetic landscape remains elusive. Recent studies demonstrated that long non-coding RNAs (lncRNAs) might play potential roles in epigenetic modulation of sex differentiation, ovarian cancer and germline stem cell survival. To further understand the influence of RU486 exposure on epigenetic regulation, we performed a comparative investigation on sex-biased gonadal lncRNAs profiles using control XX/XY and RU486-induced sex reversed XX Nile tilapia (Oreochromis niloticus) by RNA-seq. In total, 962 sexually differentially expressed lncRNAs and their target genes were screened from the gonads of control and sex reversed fish. In comparison with the control XX group, sex reversal induced by RU486 treatment led to significant up-regulation of 757 lncRNAs and down-regulation of 221 lncRNAs. Hierarchical clustering analysis revealed that global lncRNA expression profiles in RU486-treated XX group clustered into the same branch with the control XY, whereas XX control group formed a separate branch. The KEGG pathway enrichment analysis showed that the cis-target genes between RU486-XX and control-XX were concentrated in NOD − like receptor signaling pathway, Cell adhesion molecules (CAMs) and Biosynthesis of amino acids. Real-time PCR and in situ hybridization experiments demonstrate that lncRNAs showing intense fluctuation during RU486 treatment are also sexually dimorphic during early sex differentiation, which further proves the intimate relationship between lncRNAs and sex differentiation and sexual transdifferentiation. Taken together, our data strongly indicates that a long-term exposure of RU486 resulted in sex reversal of XX female fish and the altered expression of sexually dimorphic lncRNAs might partially account for the sex reversal via epigenetic modification.. |
