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Kaleta M, Oklestkova J, Klíčová K, Kvasnica M, Koníčková D, Menšíková K, Strnad M, Novák O. Simultaneous Determination of Selected Steroids with Neuroactive Effects in Human Serum by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry. ACS Chem Neurosci 2024; 15:1990-2005. [PMID: 38655788 PMCID: PMC11099924 DOI: 10.1021/acschemneuro.3c00824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/27/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
Neuroactive steroids are a group of steroid molecules that are involved in the regulation of functions of the nervous system. The nervous system is not only the site of their action, but their biosynthesis can also occur there. Neuroactive steroid levels depend not only on the physiological state of an individual (person's sex, age, diurnal variation, etc.), but they are also affected by various pathological processes in the nervous system (some neurological and psychiatric diseases or injuries), and new knowledge can be gained by monitoring these processes. The aim of our research was to develop and validate a comprehensive method for the simultaneous determination of selected steroids with neuroactive effects in human serum. The developed method enables high throughput and a sensitive quantitative analysis of nine neuroactive steroid substances (pregnenolone, progesterone, 5α-dihydroprogesterone, allopregnanolone, testosterone, 5α-dihydrotestosterone, androstenedione, dehydroepiandrosterone, and epiandrosterone) in 150 μL of human serum by ultrahigh-performance liquid chromatography with tandem mass spectrometry. The correlation coefficients above 0.999 indicated that the developed analytical procedure was linear in the range of 0.90 nmol/L to 28.46 μmol/L in human serum. The accuracy and precision of the method for all analytes ranged from 83 to 118% and from 0.9 to 14.1%, respectively. This described method could contribute to a deeper understanding of the pathophysiology of various diseases. Similarly, it can also be helpful in the search for new biomarkers and diagnostic options or therapeutic approaches.
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Affiliation(s)
- Michal Kaleta
- Laboratory
of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany
of the Czech Academy of Sciences, Šlechtitelů 27, Olomouc 783 71, Czech Republic
- Department
of Neurology, Faculty of Medicine and Dentistry, Palacký University, Olomouc 779 00, Czech Republic
| | - Jana Oklestkova
- Laboratory
of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany
of the Czech Academy of Sciences, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Kateřina Klíčová
- Department
of Neurology, Faculty of Medicine and Dentistry, Palacký University, Olomouc 779 00, Czech Republic
- Department
of Neurology, University Hospital Olomouc, Olomouc 779 00, Czech Republic
| | - Miroslav Kvasnica
- Laboratory
of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany
of the Czech Academy of Sciences, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Dorota Koníčková
- Department
of Neurology, Faculty of Medicine and Dentistry, Palacký University, Olomouc 779 00, Czech Republic
- Department
of Neurology, University Hospital Olomouc, Olomouc 779 00, Czech Republic
| | - Kateřina Menšíková
- Department
of Neurology, Faculty of Medicine and Dentistry, Palacký University, Olomouc 779 00, Czech Republic
- Department
of Neurology, University Hospital Olomouc, Olomouc 779 00, Czech Republic
| | - Miroslav Strnad
- Laboratory
of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany
of the Czech Academy of Sciences, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Ondřej Novák
- Laboratory
of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany
of the Czech Academy of Sciences, Šlechtitelů 27, Olomouc 783 71, Czech Republic
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Hobo Y, Nishikawa J, Asai-Taniguchi N, Yoneyama K, Watanabe Y, Miyashiro Y, Fujikata A. Evaluation of the therapeutic effects of AGA drugs by measuring finasteride, dutasteride, and dihydrotestosterone in hair. Clin Chim Acta 2023:117456. [PMID: 37385468 DOI: 10.1016/j.cca.2023.117456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/23/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
BACKGROUND Androgenetic alopecia (AGA) is treated by 5α-reductase inhibitors (5ARI) such as finasteride and dutasteride, which are widely used as therapeutic agents. However, their pharmacokinetics in target organs (scalp and hair follicles) have not yet been investigated. PURPOSE To confirm the effective action of finasteride and dutasteride in the hair follicle tissues, we developed a method to measure these concentrations in hair. RESULTS Compared to the non-detection (N.D.) group, the dihydrotestosterone (DHT) concentrations decreased significantly in both the finasteride and dutasteride groups. The dutasteride group showed significantly lower DHT concentrations among all groups. CONCLUSIONS Measurement of finasteride, dutasteride, and DHT concentrations in hair would aid in evaluating the drug pharmacokinetics and its therapeutic effects on AGA patients.
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Affiliation(s)
- Yoshitaka Hobo
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan.
| | - Jun Nishikawa
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Noriko Asai-Taniguchi
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Keisuke Yoneyama
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Yoko Watanabe
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Yoshimichi Miyashiro
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Akira Fujikata
- ASKA Pharmamedical Co., Ltd. 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
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Higashi T, Aso S, Horisaki H, Ito T, Tanaka S, Nishimoto-Kusunose S, Ogawa S, Kato K, Ide H. Evaluation of thumbnail clipping as a specimen for retrospectively assessing average production of testosterone. Clin Chim Acta 2023; 538:157-163. [PMID: 36417978 DOI: 10.1016/j.cca.2022.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND The chronic abnormal production of testosterone (T) is associated with many disorders in men. Fingernail clippings might be more suited for the diagnosis and medium-to-long term therapeutic monitoring for the T-related chronic disorders than the blood-derived specimens. The objective of this study was to characterize a thumbnail clipping as the specimen for assessing the several months-old T status. METHODS Thumbnail clippings from various subjects were analyzed by liquid chromatography/electrospray ionization-tandem mass spectrometry to evaluate the gender difference, and changes caused by aging and androgen deprivation therapy (ADT) in the thumbnail T concentration. RESULTS There was an evident gender difference in the thumbnail T concentrations [male; 2.55 ± 0.85 ng/g and female; 0.48 ± 0.29 ng/g, mean ± SD (n = 25 each), Welch t-test]. The thumbnail T concentrations significantly decreased with age in men (n = 268, Scheffé F-test), which was similar to those of the free or bioavailable T in serum/plasma. The thumbnail T concentrations sharply decreased by a 6-months ADT (especially the effect of the luteinizing hormone-releasing hormone agonist/antagonist) for patients with prostate cancer (n = 10). CONCLUSIONS The thumbnail clipping can be a specimen to retrospectively assess the average T production.
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Affiliation(s)
- Tatsuya Higashi
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
| | - Saki Aso
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Hiroaki Horisaki
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Takenori Ito
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Sakurako Tanaka
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Shoichi Nishimoto-Kusunose
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Shoujiro Ogawa
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 1 Sanzo, Gakuen-cho, Fukuyama, Hiroshima 729-0292, Japan
| | - Kazuhiko Kato
- ASKA Pharma Medical Co., Ltd., 2-26-1 Muraoka-higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Hisamitsu Ide
- Department of Urology, Dokkyo Medical University Saitama Medical Center, 2-1-50 Minami-koshigaya, Koshigaya, Saitama 343-8555, Japan
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Liao HY, Xiao X, Peng R, Le J, Wang HB, Wang ST. Rapid Derivatization of Phenolic and Oxime Hydroxyl with Isonicotinoyl Chloride under Aqueous Conditions and Its Application in LC-MS/MS Profiling Multiclass Steroids. Anal Chem 2022; 94:17980-17987. [PMID: 36521069 DOI: 10.1021/acs.analchem.2c04151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Quantification of steroids possesses a crucial clinical value in early diagnosis and prognosis evaluation of various endocrine diseases. However, it is still challenging to realize feasible analysis of estrogens, androgens, progestogens, and corticoids within one single workflow. In this study, two derivatization reactions were newly designed for improvement: (1) acylation of phenolic hydroxyl on estrogens with isonicotinoyl chloride (INC) under the catalysis of 4-dimethylaminopyridine and (2) post-modification of oxime hydroxyl on hydroxylamine-pretreated ketosteroids with INC. Both reactions could conduct instantaneously at room temperature under aqueous conditions. Moreover, the resulting phenolic-INC and oxime-INC esters exhibited favorable MS responses. Through integrating these derivatization strategies with cold-induced phase separation technology, a feasible LC-MS/MS method was developed for simultaneous quantification of 15 multiclass steroids with proper sample consumption (50 μL serum), satisfying sensitivity (lower limit of quantitation at 0.01-5.00 ng/mL) and high throughput (40 min for sample-preparation). The practical applicability was tested by detecting 30 real samples from pregnant and non-pregnant women. The obtained results showed a good agreement with a previous validated methodology.
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Affiliation(s)
- Hui-Yang Liao
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Xuan Xiao
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Rui Peng
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Juan Le
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Hai-Bo Wang
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Shao-Ting Wang
- Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, China
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Luo Y, Zhang C, Ma L, Zhang Y, Liu Z, Chen L, Wang R, Luan Y, Rao Y. Measurement of 7-dehydrocholesterol and cholesterol in hair can be used in the diagnosis of Smith-Lemli-Opitz syndrome. J Lipid Res 2022; 63:100228. [PMID: 35577137 PMCID: PMC9207299 DOI: 10.1016/j.jlr.2022.100228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/06/2022] [Accepted: 05/08/2022] [Indexed: 11/20/2022] Open
Abstract
7-dehydrocholesterol (7-DHC) and cholesterol (CHOL) are biomarkers of Smith-Lemli-Opitz Syndrome (SLOS), a congenital autosomal recessive disorder characterized by elevated 7-DHC level in patients. Hair samples have been shown to have great diagnostic and research value, which has long been neglected in the SLOS field. In this study, we sought to investigate the feasibility of using hair for SLOS diagnosis. In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), hair samples were completely pulverized and extracted by micro-pulverized extraction in alkaline solution or in n-hexane. After microwave-assisted derivatization with N,O-Bis(trimethylsilyl)trifluoroacetamide, the analytes were measured by GC-MS. We found that the limits of determination for 7-DHC and CHOL were 10 ng/mg and 8 ng/mg, respectively. In addition, good linearity was obtained in the range of 50–4000 ng/mg and 30–6000 ng/mg for 7-DHC and CHOL, respectively, which fully meets the requirement for SLOS diagnosis and related research. Finally, by applying the proposed method to real hair samples collected from 14 healthy infants and two suspected SLOS patients, we confirmed the feasibility of hair analysis as a diagnostic tool for SLOS. In conclusion, we present an optimized and validated analytical method for the simultaneous determination of two SLOS biomarkers using human hair.
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A quantitative ultra-performance liquid chromatography high-resolution mass spectrometry analysis of steroids from human scalp hair. J Pharm Biomed Anal 2022; 215:114768. [DOI: 10.1016/j.jpba.2022.114768] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 11/19/2022]
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Hobo Y, Nishikawa J, Miyashiro Y, Fujikata A. Analysis of hair steroid hormone concentrations at different parts of the head by liquid chromatography-tandem mass spectrometry. Clin Chim Acta 2021; 523:260-266. [PMID: 34627827 DOI: 10.1016/j.cca.2021.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 09/13/2021] [Accepted: 10/05/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Steroid hormones are known to be associated with diseases like androgenetic alopecia (AGA) resulting in hair loss. The lack of a detailed analysis of the local concentration of steroids in different parts of the head underlies the rationale and purpose of this study. METHODS To evaluate the concentration distributions of steroid hormones in hair in different parts of the head, hair samples of 8 healthy men from 9 point-areas covering the frontal, parietal, and occipital regions were collected. Eight steroid hormones were measured by using the LC-MS/MS and region-wise comparison for different hormones was done using the mean z-score and Tukey's HSD. RESULTS Five of the 8 hormones had a high concentration in the parietal region, with dihydrotestosterone (DHT) showing a peak in the central parietal region (z = 1.59) suggesting a correlation with AGA's clinical presentation. Whereas, no significant differences were observed for testosterone and cortisol between the parietal and occipital regions. Higher DHT levels at the parietal region were also verified with a small group of AGA patients. CONCLUSIONS This research expands upon the role of steroid hormones in hair follicle tissue elucidating their relationship with disease, thus contributing to disease management.
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Affiliation(s)
- Yoshitaka Hobo
- ASKA Pharmamedical Co., Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan.
| | - Jun Nishikawa
- ASKA Pharmamedical Co., Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Yoshimichi Miyashiro
- ASKA Pharmamedical Co., Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
| | - Akira Fujikata
- ASKA Pharmamedical Co., Ltd., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, Japan
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Fast accurate quantification of salivary cortisol and cortisone in a large-scale clinical stress study by micro-UHPLC-ESI-MS/MS using a surrogate calibrant approach. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1182:122939. [PMID: 34547590 DOI: 10.1016/j.jchromb.2021.122939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 09/04/2021] [Accepted: 09/06/2021] [Indexed: 11/23/2022]
Abstract
Cortisol and cortisone are common markers for stress and thus preferentially analyzed in matrices that allow non-invasive sampling such as saliva. Though the major drawback of immunoassays is lack of specificity due to cross reactivities, they are still most commonly used for quantification of steroid hormones. To overcome such problems, sensitive methods based on liquid chromatography-mass spectrometry are becoming more and more accepted as the golden standard for steroid bioanalysis as they achieve accurate quantification at trace levels for multiple analytes in the same run. Along this line, the aim of this study was the development of a new microflow UHPLC-ESI-MS/MS method for the measurement of salivary cortisol and cortisone, which due to its microflow regime provides enhanced sensitivity and is more ecofriendly. The developed method implemented sample preparation by Solid-Phase Extraction (SPE) in a 96-well plate format. Data acquisitions were carried out in MRM (multiple reaction monitoring) mode. The quantitative determination of endogenous compounds in saliva remains a challenge since analyte-free matrix is lacking. Hence, a surrogate calibrant approach with cortisol-d4 andcortisone-13C3 was applied for the target compounds in the presented method. A number of factors were optimized and the method validated. The lower limit of quantitation (LLOQ) was 72 and 62 pg mL-1for cortisol and cortisone, respectively. Linear calibration was achieved in the range from 0.062 to 75.5 ng mL-1for cortisol-d4 and 0.072 to 44 ng mL-1forcortisone-13C3. The performance of the method was also evaluated via proficiency test for salivary cortisol. Finally, it was applied successfully to evaluate cortisol and cortisone concentrations in multiple batches in routine clinical stress study samples (4056 total injections with 1983 study samples). Moreover, the instrument performance (in particular retention time variability) within each batch, between different batches and lot-to-lot of 5 investigated capillary columns over time is described. The work documents that micro-UHPLC-ESI-MS/MS is suitable and robust enough to carry out a full clinical study with greater than 1000s of samples over an extended period if adequate internal standards can be used.
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Nishiike Y, Miyazoe D, Togawa R, Yokoyama K, Nakasone K, Miyata M, Kikuchi Y, Kamei Y, Todo T, Ishikawa-Fujiwara T, Ohno K, Usami T, Nagahama Y, Okubo K. Estrogen receptor 2b is the major determinant of sex-typical mating behavior and sexual preference in medaka. Curr Biol 2021; 31:1699-1710.e6. [PMID: 33639108 DOI: 10.1016/j.cub.2021.01.089] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/07/2020] [Accepted: 01/25/2021] [Indexed: 01/02/2023]
Abstract
Male and female animals typically display innate sex-specific mating behaviors, which, in vertebrates, are highly dependent on sex steroid signaling. While estradiol-17β (E2) signaling through estrogen receptor 2 (ESR2) serves to defeminize male mating behavior in rodents, the available evidence suggests that E2 signaling is not required in teleosts for either male or female mating behavior. Here, we report that female medaka deficient for Esr2b, a teleost ortholog of ESR2, are not receptive to males but rather court females, despite retaining normal ovarian function with an unaltered sex steroid milieu. Thus, contrary to both prevailing views in rodents and teleosts, E2/Esr2b signaling in the brain plays a decisive role in feminization and demasculinization of female mating behavior and sexual preference in medaka. Further behavioral testing showed that mutual antagonism between E2/Esr2b signaling and androgen receptor-mediated androgen signaling in adulthood induces and actively maintains sex-typical mating behaviors and preference. Our results also revealed that the female-biased sexual dimorphism in esr2b expression in the telencephalic and preoptic nuclei implicated in mating behavior can be reversed between males and females by altering the sex steroid milieu in adulthood, likely via mechanisms involving direct E2-induced transcriptional activation. In addition, Npba, a neuropeptide mediating female sexual receptivity, was found to act downstream of E2/Esr2b signaling in these brain nuclei. Collectively, these functional and regulatory mechanisms of E2/Esr2b signaling presumably underpin the neural mechanism for induction, maintenance, and reversal of sex-typical mating behaviors and sexual preference in teleosts, at least in medaka.
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Affiliation(s)
- Yuji Nishiike
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Daichi Miyazoe
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Rie Togawa
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Keiko Yokoyama
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Kiyoshi Nakasone
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Masayoshi Miyata
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Yukiko Kikuchi
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
| | - Yasuhiro Kamei
- Spectrography and Bioimaging Facility, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
| | - Takeshi Todo
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Tomoko Ishikawa-Fujiwara
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kaoru Ohno
- Division of Reproductive Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
| | - Takeshi Usami
- Division of Reproductive Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
| | - Yoshitaka Nagahama
- Division of Reproductive Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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