Mar. 2017, 日本水産学会, 平成29年度日本水産学会論文賞　　　　　　　　　　　　　　　
桑田知宣;徳原哲也;清水宗敬;吉崎悟朗

Interaction between body size and commencement of smoltification in masu salmon Oncorhynchus masou
Yuki Ugachi, Haruka Kitade, Eisuke Takahashi, Ayaka Izutsu, Munetaka Shimizu
Journal of Fish Biology, in press, Mar. 2025, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, 48408472

Production of recombinant masu salmon insulin-like growth factor binding protein-2b1 and its action on pituitary cells　　　　　　　　　　　　　　　
Takuto Miura, Sota Watanabe, Ryosuke Kizaki, Ryuya Hasegawa, Taiga Isozaki, Munetaka Shimizu
General and Comparative Endocriology, 363, 114674, 16 Feb. 2025, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Producing a better smolt: Can ‘winter’ treatments combining low temperature and short daylength photoperiods enhance the smolt quality of Atlantic salmon?
Daniel W. Montgomery, Benjamin Negrete, Le Thi Hong Gam, Ayaka Izutsu, Brett M. Culbert, Nicholas J. Bernier, Munetaka Shimizu, Colin J. Brauner, Jeffrey G. Richards
Aquaculture, 596, 15 Feb. 2025, [Peer-reviewed]
Scientific journal

Profiling growth performance, insulin-like growth factors (IGFs), and IGF-binding proteins (IGFBPs) in rainbow trout lacking IGFBP-2b.
Beth M Cleveland, Ayaka Izutsu, Yuika Ushizawa, Lisa Radler, Munetaka Shimizu
American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 14 Oct. 2024, [Peer-reviewed], [Last author], [International Magazine]
English, Scientific journal, Insulin-like growth factor binding proteins (IGFBP) regulate insulin-like growth factor (IGF) signaling, but IGFBP-specific functions are not well characterized in fishes. A line of rainbow trout (Oncorhynchus mykiss) lacking a functional IGFBP-2b was produced using gene editing and subsequent breeding to an F2 generation. This loss-of-function model (2bKO) was subjected to either continuous feeding or feed deprivation (3 wk) followed by refeeding (1 wk). During continuous feeding, the 2bKO line displayed faster specific growth rate for both body weight and fork length, higher feed intake, and reduced feed conversion ratio compared to a wild type (WT) line. However, loss of IGFBP-2b did not affect the feed deprivation or refeeding response in terms of weight loss or weight gain, respectively. Several components of the IGF/IGFBP system were affected by loss of IGFBP2b. Total serum IGF-1 in the 2bKO line was reduced to 0.5 - 0.8-fold of the WT line although the concentration of free serum IGF-1 was not affected. Gene expression differences include reduced abundance of igfbp1a1, igfbp1b2, igfbp5b2, and igfbp6b1 transcripts, and elevated igf2 and igfbp6b2 transcripts in liver of the 2bKO line. Collectively, these findings suggest that although IGFBP-2b is a carrier of circulating IGF-1 in salmonids, the presence of IGFBP-2a and compensatory responses of other IGF/IGFBP system components support an anabolic response that improved growth performance in the loss-of-function model.

Effects of feeding status and water temperature on swimming performance in juvenile chum salmon (Oncorhynchus keta).
Mitsuru Torao, Wenda Cui, Munetaka Shimizu
Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 111702, 111702, 17 Jul. 2024, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, We examined the effects of feeding status in freshwater and then subsequent seawater rearing temperature on growth, critical swimming speed (Ucrit), and circulating insulin-like growth factor (IGF)-1 in juvenile chum salmon. Chum salmon fry weighing about 1.0 g were fed at 0, 1 or 3% body weight (BW) for 5 days in freshwater, acclimated to seawater at 4, 7 or 10 °C and then reared for 8 days with satiation feeding. Both freshwater feeding history and seawater rearing temperature affected fork length (FL), BW, IGF-1 levels and relative Ucrit (FL/s) 8 days after seawater transfer. Relative Ucrit positively correlated with FL and IGF-1 levels, suggesting an improvement in swimming ability attributed to growth. In a second experiment, we examined the effects of body size and growth on serum IGF-1, IGF-binding proteins (IGFBPs), and Ucrit. The chum salmon fry were sorted into large (1.5 g) or small (1.2 g) groups. They were acclimated to seawater at 10 °C and fed at 1 or 4% BW for two months. Despite the differences in serum IGF-1 levels, there were no differences in relative Ucrit among the groups. In contrast, absolute Ucrit (cm/s) was correlated with FL and IGF-1 levels. Absolute Ucrit negatively correlated with serum IGFBP-1b levels. The present study showed that poor feeding in freshwater followed by transfer to seawater at low temperature has profound effects on the growth and swimming ability of juvenile chum salmon, which may be linked to alterations in circulating IGF-1 and IGFBPs.

Size-driven parr-smolt transformation in masu salmon (Oncorhynchus masou).
Yuki Ugachi, Haruka Kitade, Eisuke Takahashi, Shotaro Suzuki, Mizuki Hayashi, Taiga Yamada, Wenda Cui, Munetaka Shimizu
Scientific Reports, 13, 1, 16643, 16643, 03 Oct. 2023, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Anadromous salmonids exhibit partial migration, where some individuals within a population migrate down to the ocean through complex interactions between body size and photoperiod. This study aimed to integrate the ontogenetic and seasonal patterns of smoltification, a series of changes for future marine life, in a strain of masu salmon (Oncorhynchus masou). Spring smoltification, as evidenced by the activation of gill Na+,K+-ATPase (NKA), was induced during winter under an advanced photoperiod. In addition, juveniles showed an additional peak in gill NKA activity in August regardless of the photoperiod. When juvenile masu salmon were subjected to feeding manipulations during the first spring/summer, only fish exceeding a fork length of 12 cm exhibited an increased gill NKA activity. We tested whether size-driven smoltification required a long-day period by exposing juveniles to a constant short-day length (9-h light and 15-h dark) from January to November. Juveniles under short-day conditions exceeded 12 cm in June but showed no signs of smoltification. Thus, masu salmon undergo photoperiod-limited, size-driven smoltification during the first summer and size-limited, photoperiod-driven smoltification the following spring. The findings of the present study provide a framework for further elucidation of the physiological mechanisms underlying partial migration in salmonids.

Evaluation of binding capacity of circulating insulin-like growth factor binding protein-1b in salmonids using a ligand immunofunctional assay.
Momoka Arimoto, Ayaka Izutsu, Akihiko Hara, Munetaka Shimizu
Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 284, 111488, 111488, Oct. 2023, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Insulin-like growth factor-binding proteins (IGFBPs) regulate the activity of insulin-like growth factor (IGF)-1. Among the three major circulating IGFBPs in salmonids, IGFBP-1b is an inhibitor of IGF activity induced under catabolic conditions. IGFBP-1b is considered to quickly sequester IGF-1 from the circulation. However, the level of circulating IGFBP-1b present in its unoccupied free form is unknown. Here, we aimed to develop a non-equilibrium ligand immunofunctional assay (LIFA) to evaluate IGF-binding capacity of circulating intact IGFBP-1b. Purified Chinook salmon IGFBP-1b, its antiserum, and europium-labeled salmon IGF-1 were used as the assay components. In the LIFA, IGFBP-1b was first captured by the antiserum, allowed to bind to the labeled IGF-1 for 22 h at 4 °C, and quantified its IGF-binding capacity. Serial dilutions of the standard and serum were prepared simultaneously within a certain concentration range (1.1-12.5 ng/ml). In underyearling masu salmon, IGF-binding capacity of intact IGFBP-1b was higher in fasted fish than in fed fish. Transferring Chinook salmon parr to seawater also increased IGF-binding capacity of IGFBP-1b, most likely due to osmotic stress. In addition, there was a strong relationship between total IGFBP-1b levels and its IGF-binding capacity. These results suggest that IGFBP-1b expressed under stress is mostly present in the free form. On the contrary, during smoltification of masu salmon, IGF-binding capacity of IGFBP-1b in the serum was relatively low and less related to the total IGFBP-1b level, suggesting its functional difference under certain physiological conditions. These results indicate that estimating both total IGFBP-1b level and its IGF-binding capacity is useful for evaluating the catabolic status and unraveling the regulation of IGF-1 activity by IGFBP-1b.

Development of a time-resolved fluoroimmunoassay for salmonid insulin-like growth factor binding protein-2b.
Ayaka Izutsu, Shiori Habara, Nobuto Kaneko, Daiji Tadokoro, Akihiko Hara, Munetaka Shimizu
General and Comparative Endocrinology, 340, 114305, 114305, 01 Sep. 2023, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Insulin-like growth factor (IGF)-1 promotes the growth of vertebrates, and its binding proteins (IGFBPs) regulate the activity of circulating IGF-1. Three IGFBPs, IGFBP-2b, -1a, and -1b, were consistently detected in the circulatory system of salmonids. IGFBP-2b is thought to be the main carrier of IGFs and promoter of IGF-1-mediated growth in salmonids. Currently, there are no immunoassays for detecting IGFBP-2b. In this study, we developed a time-resolved fluoroimmunoassay (TR-FIA) for IGFBP-2b detection in salmonid fishes. To establish TR-FIA, we produced two recombinant trout (rt) IGFBP-2bs expressed, one with thioredoxin (Trx) and a histidine (His) tag, and the other with His-tag only. We labeled both recombinant proteins with europium (Eu). Only Eu-Trx.His.rtIGFBP-2b cross-reacted with anti-IGFBP-2b, and the addition of increasing amounts of Trx.His.rtIGFBP-2b replaced the binding, indicating its utility as a tracer and assay standard. The addition of unlabeled salmon IGF-1 did not affect the binding of the standard or sample. Serial dilution curves of sera from rainbow trout, Chinook salmon, and chum salmon were parallel to those of the standard. The assay range (ED80-ED20) of the TR-FIA was 60.4 to 251.3 ng/ml, and its minimum detection limit of this assay was 21 ng/ml. The intra- and inter-assay coefficients of variation were 5.68% and 5.65%, respectively. Circulating IGFBP-2b levels in fed rainbow trout were higher than those in fasted fish and were correlated with individual growth rates. This TR-FIA is useful for further exploring the physiological responses of circulating IGFBP-2b and evaluating the growth status of salmonids.

Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na+, K+-ATPase and body size.
Wenda Cui, Eisuke Takahashi, Bernat Morro, Pablo Balseiro, Amaya Albalat, Cindy Pedrosa, Simon Mackenzie, Tom O Nilsen, Harald Sveier, Lars O Ebbesson, Sigurd O Handeland, Munetaka Shimizu
Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 268, 111205, 111205, Jun. 2022, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Smoltification in salmonids occurs during spring in response to increasing photoperiod to prepare for marine life. Smoltification is associated with increased hypo-osmoregulatory ability and enhanced growth potential, mediated by growth hormone and insulin-like growth factor (IGF)-1. Rainbow trout is uniquely insensitive to the induction of smoltification-associated changes by photoperiod, such as the activation of gill Na+,K+-ATPase (NKA). We measured the circulating IGF-1 and IGF-binding protein (IGFBP)-2b levels in yearling rainbow trout exposed to natural and manipulated photoperiods during spring and correlated these with gill NKA activity and body size. Although the effect of photoperiod manipulation on body size and circulating IGF-1 and IGFBP-2b was negligible, they were positively correlated with gill NKA activity in fish under simulated natural photoperiod. We next pit-tagged yearling rainbow trout and fed them a restricted ration or to satiation under a natural photoperiod. In April, gill NKA activity was higher in the satiation group than in the restricted group and positively correlated with body size and growth rate. In addition, circulating IGFBP-2b was positively correlated with gill NKA, size and growth, whereas circulating IGF-1 was correlated only with size and growth. The relationship between circulating IGF-1 and growth intensified from May to June, suggesting that the IGF-1-growth relationship was disrupted in April when gill NKA was activated. Two additional IGFBPs were related to growth parameters but not to gill NKA activity. The present study suggests that circulating IGFBP-2b and IGF-1 mediate the size-dependent activation of gill NKA in yearling rainbow trout during spring.

Evaluation of circulating insulin-like growth factor (IGF)-I and IGF-binding proteins as growth indices in rainbow trout (Oncorhynchus mykiss).
Ayaka Izutsu, Daiji Tadokoro, Shiori Habara, Yuki Ugachi, Munetaka Shimizu
General and Comparative Endocrinology, 320, 114008, 114008, 01 May 2022, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Circulating insulin-like growth factor (IGF)-I has been proposed as a growth index in several teleosts, including salmonids, and its level in circulation is stabilized by multiple IGF-binding proteins (IGFBPs). Three IGFBPs, IGFBP-2b, -1a, and -1b, are consistently detected in salmonid blood and are suggested to be indices of positive or negative growth, although their applicability to rainbow trout (Oncorhynchus mykiss) is unclear. The present study examined the usefulness of IGFBPs along with IGF-I as a physiological indicator of growth rate in rainbow trout through a rearing experiment. Two groups of underyearling rainbow trout were pit-tagged and either fed or fasted for 33 days. A third group was fasted for 22 days, followed by refeeding for 11 days. Serum IGF-I levels were reduced after fasting for 22 days, but refeeding did not retore its levels to those of the fed control. Nevertheless, there was a positive relationship between serum IGF-I levels and individual growth rates over 33 days of experimentation, confirming its validity as a growth index. Ligand blotting using labeled human IGF-I revealed two IGFBP bands at 43 and 32 kDa, which corresponded to IGFBP-2b and an unidentified form, respectively. In contrast, bands corresponding to IGFBP-1a and -1b, which usually increase after fasting, were hardly detected, even in the fasted fish. The responses of circulating IGFBP-2b to fasting and refeeding were similar to those of circulating IGF-I and positively correlated with growth rate and IGF-I levels. The intensity of the serum 32-kDa IGFBP band was higher in constantly fed fish than in the fasted fish; however, its correlation with growth rate was weaker than those of IGF-I and IGFBP-2b. The present study shows that IGF-I and IGFBP-2b can be used as growth indices for rainbow trout. In contrast, circulating IGFBP-1a and -1b may not serve as negative growth indices in rainbow trout under regular aquaculture conditions because they are rarely detected by ligand blotting or respond to fasting/refeeding.

Effects of acclimation to diluted seawater on metabolic and growth parameters of underyearling masu Salmon (Oncorhynchus masou).
Mizuki Hayashi, Shu Maruoka, Jin Oikawa, Yuki Ugachi, Munetaka Shimizu
Zoological Science, 38, 6, 513, 522, Dec. 2021, [Peer-reviewed], [Last author, Corresponding author], [Domestic magazines]
English, Scientific journal, We examined the effects of environmental salinity and feeding status on the growth and metabolic parameters of underyearling masu salmon. Fish were first acclimated to salinities of 0 (< 0.1), 11, or 22 psu for 10 days, after which time 50% of the fish in each group were fasted for 5 days followed by refeeding for 5 days. No effects on body length/weight were observed over the 20 days from the beginning of the experiment. Gill Na+, K+-ATPase (NKA) activity increased 20 and 10 days after transfer to water at 11 and 22 psu, respectively. Serum Na+ and Cl- levels were high in fish at 22 psu on day 20 but much lower than those in the environmental water, suggesting that fish at this salinity were able to hypo-osmoregulate. However, acclimation to 22 psu resulted in a reduction in feeding rate on day 20. Serum insulin-like growth factor (IGF)-I levels and liver glycogen content were reduced by fasting and restored after 5 days of refeeding, except in the fish at 22 psu. Intensities of serum IGFBP-1a and -1b bands were increased at higher salinities, whereas fasting/refeeding affected only IGFBP-1b. The present study suggests that acclimating masu salmon parr to 11 psu had no effect on metabolic and growth parameters, while 22 psu presumably suppressed their growth potential due to the possible energy cost or stress for osmoregulation. The disparate responses of circulating IGFBP-1a and -1b to higher salinity and fasting highlight their utility as indices of various catabolic statuses.

Endoplasmic reticulum stress as a key mechanism in stunted growth of seawater rainbow trout (Oncorhynchus mykiss).
Bernat Morro, Richard Broughton, Pablo Balseiro, Sigurd O Handeland, Simon Mackenzie, Mary K Doherty, Phillip D Whitfield, Munetaka Shimizu, Marnix Gorissen, Harald Sveier, Amaya Albalat
BMC Genomics, 22, 1, 824, 824, 16 Nov. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal, BACKGROUND: Rainbow trout (Oncorhynchus mykiss) is a salmonid species with a complex life-history. Wild populations are naturally divided into freshwater residents and sea-run migrants. Migrants undergo an energy-demanding adaptation for life in seawater, known as smoltification, while freshwater residents display these changes in an attenuated magnitude and rate. Despite this, in seawater rainbow trout farming all fish are transferred to seawater. Under these circumstances, weeks after seawater transfer, a significant portion of the fish die (around 10%) or experience growth stunting (GS; around 10%), which represents an important profitability and welfare issue. The underlying causes leading to GS in seawater-transferred rainbow trout remain unknown. In this study, we aimed at characterising the GS phenotype in seawater-transferred rainbow trout using untargeted and targeted approaches. To this end, the liver proteome (LC-MS/MS) and lipidome (LC-MS) of GS and fast-growing phenotypes were profiled to identify molecules and processes that are characteristic of the GS phenotype. Moreover, the transcription, abundance or activity of key proteins and hormones related to osmoregulation (Gill Na+, K + -ATPase activity), growth (plasma IGF-I, and liver igf1, igfbp1b, ghr1 and ctsl) and stress (plasma cortisol) were measured using targeted approaches. RESULTS: No differences in Gill Na+, K + -ATPase activity and plasma cortisol were detected between the two groups. However, a significant downregulation in plasma IGF-I and liver igf1 transcription pointed at this growth factor as an important pathomechanism for GS. Changes in the liver proteome revealed reactive-oxygen-species-mediated endoplasmic reticulum stress as a key mechanism underlying the GS phenotype. From the lipidomic analysis, key observations include a reduction in triacylglycerols and elevated amounts of cardiolipins, a characteristic lipid class associated with oxidative stress, in GS phenotype. CONCLUSION: While the triggers to the activation of endoplasmic reticulum stress are still unknown, data from this study point towards a nutritional deficiency as an underlying driver of this phenotype.

Effects of fasting and water temperatures during transition from freshwater to seawater on juvenile chum salmon growth and metabolism
Jin Oikawa, Shu Nakamura, Nobuto Kaneko, Mitsuru Torao, Yosuke Koshino, Munetaka Shimizu
FISHERIES SCIENCE, 87, 4, 579, 588, Jul. 2021, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Effects of growth hormone and cortisol administration on plasma insulin-like growth factor binding proteins in juveniles of three subspecies of masu salmon (Oncorhynchus masou)
Ginnosuke Yamaguchi, Shiori Habara, Shotaro Suzuki, Yuki Ugachi, Hisashi Kawai, Takuro Nakajima, Munetaka Shimizu
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, 251, Jan. 2021, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Compensatory response of the somatotropic axis from IGFBP-2b gene editing in rainbow trout (Oncorhynchus mykiss).
Beth M Cleveland, Shiori Habara, Jin Oikawa, Lisa M Radler, Munetaka Shimizu
Genes, 11, 12, 10 Dec. 2020, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Rainbow trout with gene editing-induced reductions in serum insulin-like growth factor binding protein (IGFBP)-2b exhibit similar growth performance compared to fish without IGFBP-2b gene disruption. The objective of this study is to determine how the components of the insulin-like growth factor (IGF)/IGFBP system respond to a reduction in serum IGFBP-2b abundance. Editing the IGFBP-2b genes in rainbow trout resulted in an 83% decrease in serum IGFBP-2b in mutants. This resulted in a 35% reduction in serum IGF-I, which was offset by reduced expression of hepatic igfbp-1a2 and increased muscle igfr-1a; these responses suggest that an increased IGF-I signaling capacity offset reductions in serum IGF-I. During feed deprivation, the differential expression of igfbp genes supports the attenuation of the growth inhibitory response, likely due to the further reduction in serum IGF-I that alleviated the need for an IGF-inhibitory response. Unique igfbp expression patterns occurred during refeeding, suggesting an enhanced IGF-I signaling capacity in controls. Collectively, these findings support that the role of IGFBP-2b is to regulate serum IGF-I concentrations. The compensatory regulation of IGF/IGFBP system genes indicates that adjustments in other IGFBP, both circulating and at the local level, maintain IGF-I signaling at a level appropriate for the nutritional state of the fish.

Production of two recombinant insulin-like growth factor binding protein-1 subtypes specific to salmonids.
Ryuya Hasegawa, Takuto Miura, Nobuto Kaneko, Ryousuke Kizaki, Gakuto Oishi, Hanae Tanaka, Moe Sato, Munetaka Shimizu
General and Comparative Endocrinology, 299, 113606, 113606, 01 Dec. 2020, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Salmonids have four subtypes of insulin-like growth factor binding protein (IGFBP)-1, termed -1a1, -1a2, -1b1 and 1b2, owing to teleost- and a lineage-specific whole-genome duplications. We have previously produced recombinant proteins of masu salmon IGFBP-1a1 and -1b2 and conducted functional analysis. To further characterize salmonid-specific IGFBP-1s, we cloned cDNAs encoding mature proteins of IGFBP-1a2 and -1b1 from the liver of masu salmon (Oncorhynchus masou). IGFBP-1a2 and -1b1 shared a 56% amino acid sequence homology whereas their homologies with their counterparts (i.e. -1a1 and -1b2) were 77% and 82%, respectively. We next expressed recombinant masu salmon (rs) IGFBP-1a2 and -1b1 with fusion partners thioredoxin (Trx) and a His-tag using the pET-32a(+) vector system in Escherichia coli. Trx.His.rsIGFBP-1s were detected in the insoluble faction, solubilized in a buffer containing urea, and isolated by Ni-affinity chromatography. They were refolded by dialysis and cleaved from the fusion partners by enterokinase. rsIGFBP-1a2 and -1b1 were purified by reversed-phase high performance liquid chromatography. Purified rsIGFBP-1a2 and -1b1 had the ability to bind digoxigenin-labeled human IGF-I on ligand blotting. We then examined the effects of rsIGFBP-1a1, -1a2, -1b1 and -1b2 in combination with human IGF-I on growth hormone (GH) release from cultured pituitary cells of masu salmon. IGF-I alone reduced GH release while the addition of rsIGFBP-1a1, -1b1 or -1b2, but not rsIGFBP-1a2, diminished the suppressive effect of IGF-I. Addition of rsIGFBP-1s without IGF-I had no effect on GH release. These results show that rsIGFBP-1b1, along with rsIGFBP-1a1 and -1b2, inhibits IGF-I action on the pituitary in masu salmon. The lack of the effect by rsIGFBP-1a2 suggests that salmon IGFBP-1 subtypes underwent subfunction partitioning and have different degrees of IGF-inhibitory action.

Physiological changes in off-season smolts induced by photoperiod manipulation in masu salmon (Oncorhynchus masou)
Shotaro Suzuki, Eisuke Takahashi, Tom Ole Nilsen, Nobuto Kaneko, Hirokazu Urabe, Yuki Ugachi, Etsuro Yamaha, Munetaka Shimizu
AQUACULTURE, 526, Sep. 2020, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Effects of temperature and photoperiod on rainbow trout (Oncorhynchus mykiss) smoltification and haematopoiesis
Bernat Morro, Pablo Balseiro, Amaya Albalat, Simon Mackenzie, Cindy Pedrosa, Tom O. Nilsen, Shotaro Suzuki, Munetaka Shimizu, Harald Sveier, Marnix Gorissen, Lars O. E. Ebbesson, Sigurd O. Handeland
AQUACULTURE, 519, Mar. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Hypothalamic agrp and pomc mRNA responses to gastrointestinal fullness and fasting in Atlantic salmon (Salmo salar, L.)
Tharmini Kalananthan, Koji Murashita, Ivar Ronnestad, Mitsumasa Ishigaki, Kota Takahashi, Marta S. Silva, Yuki Wakabayashi, Floriana Lai, Munetaka Shimizu, Tom O. Nilsen, Enrique Pino Martinez, Ana S. Gomes
FRONTIERS IN PHYSIOLOGY, 11, Feb. 2020, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Intact rather than total circulating insulin-like growth factor binding protein-1a is a negative indicator of growth in masu salmon
Nobuto Kaneko, Tom Ole Nilsen, Hanae Tanaka, Akihiko Hara, Munetaka Shimizu
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 318, 2, R329, R337, Feb. 2020, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Utilization of an endocrine growth index, insulin-like growth factor binding protein (IGFBP)-1b, for postsmolt coho salmon in the Strait of Georgia, British Columbia, Canada
Nobuto Kaneko, Meredith L. Journey, Chrys M. Neville, Marc Trudel, Brian R. Beckman, Munetaka Shimizu
FISH PHYSIOLOGY AND BIOCHEMISTRY, 45, 6, 1867, 1878, Dec. 2019, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Fasting in freshwater severely affects growth of juvenile chum salmon when entering cold seawater
Shu Nakamura, Nobuto Kaneko, Tatsuhiro Nonaka, Daiki Kurita, Yasuyuki Miyakoshi, Munetaka Shimizu
03 Apr. 2019, [Peer-reviewed]
English, Scientific journal

Effect of different photoperiod regimes on the smoltification and seawater adaptation of seawater-farmed rainbow trout (Oncorhynchus mykiss): Insights from Na+,K+-ATPase activity and transcription of osmoregulation and growth regulation genes　　　　　　　　　　　　　　　
Morro B, Balseiro P, Albalat A, Pedrosa C, Mackenzie S, Nakamura S, Shimizu M, Nilsen TO, Sveier H, Ebbesson LO, Handeland SO
Aquaculture, 507, 282, 292, Apr. 2019, [Peer-reviewed], ［Internationally co-authored］
English

Evaluation of growth status using endocrine growth indices, insulin-like growth factor (IGF)-I and IGF-binding protein-1b, in out-migrating juvenile chum salmon.
Kaneko N, Torao M, Koshino Y, Fujiwara M, Miyakoshi Y, Shimizu M
General and comparative endocrinology, 274, 50, 59, Jan. 2019, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Editing the duplicated insulin-like growth factor binding protein-2b gene in rainbow trout (Oncorhynchus mykiss)
Cleveland Beth M, Yamaguchi Ginnosuke, Radler Lisa M, Shimizu Munetaka
SCIENTIFIC REPORTS, 8, 30 Oct. 2018, [Peer-reviewed], [Last author], ［Internationally co-authored］

Assessment of the timing and degree of smolt development in southern populations of masu salmon Oncorhynchus masou
Inatani Yu, Ineno Toshinao, Sone Shiori, Matsumoto Naoto, Uchida Katsuhisa, Shimizu Munetaka
JOURNAL OF FISH BIOLOGY, 93, 3, 490, 500, Sep. 2018, [Peer-reviewed], [Last author, Corresponding author]

Comparison between Atlantic salmon Salmo salar post-smolts reared in open sea cages and in the Preline raceway semi-closed containment aquaculture system
Balseiro Pablo, Moe Oyvind, Gamlem Ingrid, Shimizu Munetaka, Sveier Harald, Nilsen Tom O, Kaneko Nobuto, Ebbesson Lars, Pedrosa Cindy, Tronci Valentina, Nylund Are, Handel, Sigurd O
JOURNAL OF FISH BIOLOGY, 93, 3, 567, 579, Sep. 2018, [Peer-reviewed], ［Internationally co-authored］

Production of recombinant salmon insulin-like growth factor binding protein-1 subtypes.
Hanae Tanaka, Gakuto Oishi, Yusuke Nakano, Hiroko Mizuta, Yuta Nagano, Naoshi Hiramatsu, Hironori Ando, Munetaka Shimizu
General and comparative endocrinology, 257, 184, 191, 01 Feb. 2018, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Insulin-like growth factor (IGF)-I is a growth promoting hormone that exerts its actions through endocrine, paracrine and autocrine modes. Local IGF-I is essential for normal growth, whereas circulating IGF-I plays a crucial role in regulating the production and secretion of growth hormone (GH) by the pituitary gland. These actions of IGF-I are modulated by six insulin-like growth factor binding proteins (IGFBPs). In teleosts, two subtypes of each IGFBP are present due to an extra round of whole-genome duplication. IGFBP-1 is generally inhibitory to IGF-I action under catabolic conditions such as fasting and stress. In salmon, IGFBP-1a and -1b are two of three major circulating IGFBPs and assumed to affect growth through modulating IGF-I action. However, exact functions of salmon IGFBP-1 subtypes on growth regulation are not known due to the lack of purified or recombinant protein. We expressed recombinant salmon (rs) IGFBP-1a and -1b with a fusion protein (thioredoxin, Trx) and a His-tag using the pET-32a(+) vector expression system in Escherichia coli. Trx.His.rsIGFBP-1s were isolated by Ni-affinity chromatography, enzymatically cleaved by enterokinase to remove the fusion partners and further purified by reversed-phase HPLC. We next examined effects of rsIGFBP-1a and -1b in combination with human IGF-I on GH release from cultured masu salmon (Oncorhynchus masou) pituitary cells. Unexpectedly, IGF-I increased GH release and an addition of rsIGFBP-1a, but not rsIGFBP-1b, restored GH levels. The results suggest that IGFBP-1a can inhibit IGF-I action on the pituitary in masu salmon. Availability of recombinant salmon IGFBP-1s should facilitate further functional analyses and assay development.

Circulating insulin-like growth factor binding proteins in fish: Their identities and physiological regulation
Munetaka Shimizu, Walton W. Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 252, 150, 161, Oct. 2017, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English

Effects of seawater transfer and fasting on the endocrine and biochemical growth indices in juvenile chum salmon (Oncorhynchus keta)
Natsumi Taniyama, Nobuto Kaneko, Yu Inatani, Yasuyuki Miyakoshi, Munetaka Shimizu
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 236, 146, 156, Sep. 2016, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Body size is the primary regulator affecting commencement of smolting in amago salmon Oncorhynchus masou ishikawae
Tomonori Kuwada, Tetsuya Tokuhara, Munetaka Shimizu, Goro Yoshizaki
FISHERIES SCIENCE, 82, 1, 59, 71, Jan. 2016, [Peer-reviewed]
English, Scientific journal

Role of the GH-IGF-1 system in Atlantic salmon and rainbow trout postsmolts at elevated water temperature
Ernst M. Hevroy, Christian K. Tipsmark, Sofie C. Remo, Tom Hansen, Miki Fukuda, Thomas Torgersen, Vibeke Vikesa, Pal A. Olsvik, Rune Waagbo, Munetaka Shimizu
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, 188, 127, 138, Oct. 2015, [Peer-reviewed], [Last author], ［Internationally co-authored］
English, Scientific journal

Development of a time-resolved fluoroimmunoassay for salmon insulin-like growth factor binding protein-1b
Miki Fukuda, Nobuto Kaneko, Kohei Kawaguchi, Ernst M. Hevroy, Akihiko Hara, Munetaka Shimizu
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, 187, 66, 73, Sep. 2015, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Circulating insulin-like growth factor I in juvenile chum salmon: relationship with growth rate and changes during downstream and coastal migration in northeastern Hokkaido, Japan
Nobuto Kaneko, Natsumi Taniyama, Yu Inatani, Yuta Nagano, Makoto Fujiwara, Mitsuru Torao, Yasuyuki Miyakoshi, Munetaka Shimizu
FISH PHYSIOLOGY AND BIOCHEMISTRY, 41, 4, 991, 1003, Aug. 2015, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Profiles of circulating insulin-like growth factor-I during smoltification of masu salmon reared under different conditions
Nobuto Kaneko, Anai Iijima, Takahiro Shimomura, Takuro Nakajima, Haruka Shimura, Hajime Oomori, Hirokazu Urabe, Akihiko Hara, Munetaka Shimizu
FISHERIES SCIENCE, 81, 4, 643, 652, Jul. 2015, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Lack of hormonal stimulation prevents the landlocked Biwa salmon (Oncorhynchus masou subspecies) from adapting to seawater
Takuro Nakajima, Haruka Shimura, Miyuki Yamazaki, Yasuhiro Fujioka, Kazuhiro Ura, Akihiko Hara, Munetaka Shimizu
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 307, 4, R414, R425, Aug. 2014, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Responses of insulin-like growth factor (IGF)-I and two IGF-binding protein-1 subtypes to fasting and re-feeding, and their relationships with individual growth rates in yearling masu salmon (Oncorhynchus masou)
Kohei Kawaguchi, Nobuto Kaneko, Miki Fukuda, Yusuke Nakano, Shizuo Kimura, Akihiko Hara, Munetaka Shimizu
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology, 165, 2, 191, 198, Jun. 2013, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

GH-IGF system regulation of attenuated muscle growth and lipolysis in Atlantic salmon reared at elevated sea temperatures
Ernst M. Hevroy, Christine Hunskar, Stefan de Gelder, Munetaka Shimizu, Rune Waagbo, Olav Breck, Harald Takle, Sissel Sussort, Tom Hansen
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY, 183, 2, 243, 259, Feb. 2013, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Normalizing for biology: Accounting for technical and biological variation in levels of reference gene and insulin-like growth factor 1 (igf1) transcripts in fish livers
David C. Metzger, J. Adam Luckenbach, Munetaka Shimizu, Brian R. Beckman
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, 163, 1, 7, 14, Sep. 2012, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Relationships between gill Na+,K+-ATPase activity and endocrine and local insulin-like growth factor-I levels during smoltification of masu salmon (Oncorhynchus masou)
Takahiro Shimomura, Takuro Nakajima, Moeri Horikoshi, Anai Iijima, Hirokazu Urabe, Shinya Mizuno, Naoshi Hiramatsu, Akihiko Hara, Munetaka Shimizu
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 178, 2, 427, 435, Sep. 2012, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Circulating salmon 28-and 22-kDa insulin-like growth factor binding proteins (IGFBPs) are co-orthologs of IGFBP-1
Munetaka Shimizu, Keisuke Kishimoto, Teppei Yamaguchi, Yusuke Nakano, Akihiko Hara, Walton W. Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 174, 2, 97, 106, Nov. 2011, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Circulating salmon 41-kDa insulin-like growth factor binding protein (IGFBP) is not IGFBP-3 but an IGFBP-2 subtype
Munetaka Shimizu, Seira Suzuki, Moeri Horikoshi, Akihiko Hara, Walton W. Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 171, 3, 326, 331, May 2011, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Effects of short-term starvation on ghrelin, GH-IGF system, and IGF-binding proteins in Atlantic salmon
E. M. Hevrøy, C. Azpeleta, M. Shimizu, A. Lanzén, H. Kaiya, M. Espe, P. A. Olsvik
Fish Physiology and Biochemistry, 37, 1, 217, 232, Kluwer Academic Publishers, 2011, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Postprandial changes in plasma growth hormone, insulin, insulin-like growth factor (IGF)-I, and IGF-binding proteins in coho salmon fasted for varying periods
Munetaka Shimizu, Kathleen A. Cooper, Walton W. Dickhoff, Brian R. Beckman
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 297, 2, R352, R361, Aug. 2009, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Monthly changes in the serum levels of two choriogenins and vitellogenin in male masu salmon Oncorhynchus masou
Toshiaki Fujita, Haruhisa Fukada, Munetaka Shimizu, Naoshi Hiramatsu, Akihiko Hara
FISHERIES SCIENCE, 74, 5, 1198, 1200, Oct. 2008, [Peer-reviewed]
English, Scientific journal

Molecular cloning and characterization of three distinct choriogenins in masu salmon, Oncorhynchus masou
Toshiaki Fujita, Haruhisa Fukada, Munetaka Shimizu, Naoshi Hiramatsu, Akihiko Hara
MOLECULAR REPRODUCTION AND DEVELOPMENT, 75, 7, 1217, 1228, Jul. 2008, [Peer-reviewed]
English, Scientific journal

Response of the salmon somatotropic axis to growth hormone administration under two different salinities
Munetaka Shimizu, Haruhisa Fukada, Akihiko Hara, Walton W. Dickhoff
AQUACULTURE, 273, 2-3, 320, 328, Dec. 2007, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Egg yolk proteins in gray mullet (Mugil cephalus): Purification and classification of multiple lipovitellins and other vitellogenin-derived yolk proteins and molecular cloning of the parent vitellogenin genes
Haruna Amano, Toshiaki Fujita, Naoshi Hiramatsu, Munetaka Shimizu, Sayumi Sawaguch, Takahiro Iatsubara, Hirohiko Kagawa, Masaki Nagae, Craig V. Sullivan, Akihiko Hara
JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY, 307A, 6, 324, 341, Jun. 2007, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Carp (Cyprinus carpio) Vitellogenin: Characterization of Yolk Proteins, Development of Immunoassays and Use as Biomarker of Exposure to Environmental Estrogens
HARA AKIHIKO, HIRANO KAORI, SHIMIZU MUNETAKA, FUKADA HARUHISA, FUJITA TOSHIAKI, ITO FUMINARI, TAKADA HIDESHIGE, NAKAMURA MASARU, IGUCHI TAISEN
Environ Sci (Tokyo), 14, 2, 95, 108, 2007, [Peer-reviewed]
English

Metabolic hormones regulate insulin-like growth factor binding protein-1 mRNA levels in primary cultured salmon hepatocytes; lack of inhibition by insulin
A. L. Pierce, M. Shimizu, L. Felli, P. Swanson, W. W. Dickhoff
JOURNAL OF ENDOCRINOLOGY, 191, 2, 379, 386, Nov. 2006, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Measurement of circulating salmon IGF binding protein-1: assay development, response to feeding ration and temperature, and relation to growth parameters
M Shimizu, BR Beckman, A Hara, WW Dickhoff
JOURNAL OF ENDOCRINOLOGY, 188, 1, 101, 110, Jan. 2006, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Purification of two lipovitellins and development of immunoassays for two forms of their precursors (vitellogenins) in medaka (Oryzias latipes)
Y Fujiwara, H Fukada, M Shimizu, A Hara
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 143, 3, 267, 277, Sep. 2005, [Peer-reviewed]
English, Scientific journal

Annual changes in serum levels of two choriogenins and vitellogenin in masu salmon, Oncorhynchus masou
T Fujita, H Fukada, M Shimizu, N Hiramatsu, A Hara
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY, 141, 2, 211, 217, Jun. 2005, [Peer-reviewed]
English, Scientific journal

Time course of the GH/IGF axis response to fasting and increased ration in chinook salmon (Oncorhynchus tshawytscha)
AL Pierce, M Shimizu, BR Beckman, DM Baker, WW Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 140, 3, 192, 202, Feb. 2005, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Salmon serum 22 kDa insulin-like growth factor-binding protein (IGFBP) is IGFBP-1
Munetaka Shimizu, Munetaka Shimizu, J. T. Dickey, J. T. Dickey, H. Fukada, H. Fukada, W. W. Dickhoff, W. W. Dickhoff
Journal of Endocrinology, 184, 1, 267, 276, Society for Endocrinology, 01 Jan. 2005, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English

The effect of temperature change on the relations among plasma IGF-1, 41-kDa IGFBP, and growth rate in postsmolt coho salmon
BR Beckman, M Shimizu, BA Gadberry, PJ Parkins, KA Cooper
AQUACULTURE, 241, 1-4, 601, 619, Nov. 2004, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Androgen effects on plasma GH, IGF-I, and 41-kDa IGFBP in coho salmon (Oncorhynchus kisutch)
DA Larsen, M Shimizu, KA Cooper, P Swanson, WW Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 139, 1, 29, 37, Oct. 2004, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Quantification of serum levels of precursors to vitelline envelope proteins (choriogenins) and vitellogenin in estrogen treated masu salmon, Oncorhynchus masou
T Fujita, H Fukada, M Shimizu, N Hiramatsu, A Hara
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 136, 1, 49, 57, Mar. 2004, [Peer-reviewed]
English, Scientific journal

Response of the somatotropic axis of juvenile coho salmon to alterations in plane of nutrition with an analysis of the relationships among growth rate and circulating IGF-I and 41 kDa IGFBP
BR Beckman, M Shimizu, BA Gadberry, KA Cooper
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 135, 3, 334, 344, Feb. 2004, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Immunochemical comparison between sera from the primary and secondary circulations in a salmonid fish, Sakhalin taimen (Hucho Perryi)　　　　　　　　　　　　　　　
Yuki Tokushima, Yuki Ito, Munetaka Shimizu, Akihiko Hara
Fish Physiology and Biochemistry, 30, 179, 188, 2004, [Peer-reviewed]

Disparate regulation of insulin-like growth factor-binding proteins in a primitive, ictalurid, teleost (Ictalurus punctatus)
J Johnson, J Silverstein, WR Wolters, M Shimizu, WW Dickhoff, BS Shepherd
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 134, 2, 122, 130, Nov. 2003, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Development of an RIA for salmon 41 kDa IGF-binding protein
M Shimizu, A Hara, WW Dickhoff
JOURNAL OF ENDOCRINOLOGY, 178, 2, 275, 283, Aug. 2003, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Purification of a 41-kDa insulin-like growth factor binding protein from serum of chinook salmon, Oncorhynchus tshawytscha
M Shimizu, P Swanson, A Hara, WW Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 132, 1, 103, 111, Jun. 2003, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］
English, Scientific journal

Purification and identification of a second form of vitellogenin from ascites of medaka (Oryzias latipes) treated with estrogen
M Shimizu, Y Fujiwara, H Fukada, A Hara
JOURNAL OF EXPERIMENTAL ZOOLOGY, 293, 7, 726, 735, Dec. 2002, [Peer-reviewed], [Lead author]
English, Scientific journal

Purification of serum precursor proteins to vitelline envelope (choriogenins) in masu salmon, Oncorhynchus masou
T Fujita, M Shimizu, N Hiramatsu, H Fukada, A Hara
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY, 132, 3, 599, 610, Jul. 2002, [Peer-reviewed]
English, Scientific journal

Serum Immunoglobulin M (IgM) in Sakhalin Taimen (Hucho perryi): Purification, Caracterization, Circulating Levels, and Specific IgM Production by the Parasitic Salmincola stellatus
HIRAMATSU Naoshi, FUKADA Haruhisa, KITAMURA Makiko, SHIMIZU Munetaka, FUDA Hirotoshi, KOBAYASHI Kunihiko, HARA Akihiko
水産増殖, 49, 3, 347, 355, 日本水産増殖学会, 20 Sep. 2001, [Peer-reviewed]
English, Immunoglobulin M (IgM) was purified from the serum of Sakhalin taimen (Hucho perryi) by salting-out, ion-exchange chromatography on DEAF-cellulose, and gel filtration on Sepharose 6B. The intact, tetrameric taimen IgM has a mass of 750 kDa with molecular architecture typical of IgM from other salmonids. The molecular weights of heavy (μ) chain and light chains (L) of the IgM monomer were estimated to be 68 kDa and 23 kDa, respectively. Purified taimen IgM was used to raise a specific rabbit antiserum and to develop a single radial immunodiffusion assay for measuring circulating IgM levels. The serum IgM levels in captive, immature or maturing female taimen varied between 1 and 5 mg/ml, showing seasonal changes regardless of fish age, with relatively low levels in spring and conversely high levels in autumn. Production of specific serum IgM to a parasite, Salmincola stellatus, was assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The parasitized taimen serum could react with protein components of aqueous extracts from the parasite that were blotted on a nitrocellulose membrane after SDS-PAGE, but normal taimen serum did not, indicating that the parasitized fish produced the specific IgM to S. stellatus in the serum.

Bovine growth hormone treatment of channel catfish: strain and temperature effects on growth, plasma IGF-I levels, feed intake and efficiency and body composition
JT Silverstein, WR Wolters, M Shimizu, WW Dickhoff
AQUACULTURE, 190, 1-2, 77, 88, Oct. 2000, [Peer-reviewed], ［Internationally co-authored］
English, Scientific journal

Comparison of extraction methods and assay validation for salmon insulin-like Growth Factor-I using commercially available components
Munetaka Shimizu, Penny Swanson, Haruhisa Fukada, Akihiko Hara, Walton W. Dickhoff
General and Comparative Endocrinology, 119, 1, 26, 36, Academic Press Inc., 2000, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］
English, Scientific journal

Free and protein-bound insulin-like growth factor-I (IGF-I) and IGF-binding proteins in plasma of coho salmon, Oncorhynchus kisutch
M Shimizu, P Swanson, WW Dickhoff
GENERAL AND COMPARATIVE ENDOCRINOLOGY, 115, 3, 398, 405, Sep. 1999, [Peer-reviewed], [Lead author], ［Internationally co-authored］
English, Scientific journal

Changes in serum choriogenin and vitellogenin levels in masu salmon (Oncorhynchus masou) during sexual maturation and after estrogen treatment.　　　　　　　　　　　　　　　
Fujita T, Hiramatsu N, Shimizu M, Sullivan CV, Hara A
Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, 314, 1999, [Peer-reviewed], ［Internationally co-authored］
English, International conference proceedings

Changes of serum growth hormone and vitellogenin levels in chtthroat trout during sexual maturation.　　　　　　　　　　　　　　　
Fukada H, Hiramatsu N, Shimizu M, Sullivan CV, Hara A
Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, 314, 1999, [Peer-reviewed], ［Internationally co-authored］
English, International conference proceedings

Purification of the precursors to vitelline envelope proteins from serum of Sakhalin taimen, Hucho perryi
Munetaka Shimizu, Toshiaki Fujita, Akihiko Hara
Journal of Experimental Zoology, 282, 3, 385, 395, 15 Oct. 1998, [Peer-reviewed], [Lead author]
English, Scientific journal

Purification and partial characterisation of the precursors to vitelline envelope proteins in serum of Sakhalin taimen (Hucho perryi)　　　　　　　　　　　　　　　
Munetaka Shimizu, Toshiaki Fujita, Akihiko Hara
Zygote, 6, 1, S103, 1998
English, Scientific journal

Immunochemical Detection, Estrogen Induction and Occurrence in Serum of Vitelline Envelope-Related Proteins of Sakhalin Taimen Hucho perryi
Munetaka Shimizu, Toshiaki Fujita, Naoshi Hiramatsu, Akihiko Hara
Fisheries Science, 64, 4, 600, 605, Blackwell Publishing, 1998, [Peer-reviewed], [Lead author]
English, Scientific journal

Transition of serum vitellogenin cycle in Sakhalin taimen (Hucho perryi)
N Hiramatsu, M Shimizu, H Fukada, M Kitamura, K Ura, H Fuda, A Hara
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-PHARMACOLOGY TOXICOLOGY & ENDOCRINOLOGY, 118, 2, 149, 157, Oct. 1997, [Peer-reviewed]
English, Scientific journal

Changes in serum levels of two choriogenins in Sakhalin taimen treated with estrogen
Shimizu M, Fujita T, Hara A
ADVANCES IN COMPARATIVE ENDOCRINOLOGY, TOMES 1 AND 2, 1493, 1496, 1997, [Peer-reviewed], [Lead author]

Electrophoretic changes in olfactory system proteins in masu salmon during parr-smolt transformation
M Shimizu, H Ueda, H Kawamura, K Shimazaki, K Yamauchi
JOURNAL OF FISH BIOLOGY, 47, 6, 1044, 1054, Dec. 1995, [Peer-reviewed], [Lead author]
English, Scientific journal

Species-Specificity of an Olfactory System-Specific Protein in Various Species of Teleosts
Ueda Hiroshi, Shimizu Munetaka, Kudo Hideaki, Hara Akihiko, Hiroi Osamu, Kaeriyama Masahide, Tanaka Hisao, Kawamura Hiroshi, Yamauchi Kohei
Fisheries science, 60, 2, 239, 240, The Japanese Society of Fisheries Science, 1994, [Peer-reviewed]
English

IMMUNOLOGICAL SIMILARITY BETWEEN AN OLFACTORY SYSTEM-SPECIFIC PROTEIN AND A TESTICULAR GERM-CELL PROTEIN IN KOKANEE SALMON (ONCORHYNCHUS-NERKA)
H UEDA, H KUDO, M SHIMIZU, K MOCHIDA, S ADACHI, K YAMAUCHI
ZOOLOGICAL SCIENCE, 10, 4, 685, 690, Aug. 1993, [Peer-reviewed]
English, Scientific journal

IDENTIFICATION AND IMMUNOLOGICAL PROPERTIES OF AN OLFACTORY SYSTEM-SPECIFIC PROTEIN IN KOKANEE SALMON (ONCORHYNCHUS-NERKA)
M SHIMIZU, H KUDO, H UEDA, A HARA, K SHIMAZAKI, K YAMAUCHI
ZOOLOGICAL SCIENCE, 10, 2, 287, 294, Apr. 1993, [Peer-reviewed], [Lead author]
English, Scientific journal

Physiological Tools for Evaluating Growth Status of Migrating Salmon
Munetaka Shimizu, Technical Report, 17, 29 Nov. 2021, [Lead author, Last author, Corresponding author]
North Pacific Anadromous Fish Commission, English, Technical report, 45296193

Low Nutritional Status in the Freshwater Phase and Temperature at Seawater Entry Reduce Swimming Performance of Juvenile Chum Salmon
Mitsuru Torao, Yasuyuki Miyakoshi, Munetaka Shimizu, Technical Report, 17, 29 Nov. 2021
North Pacific Anadromous Fish Commission

ニジマスのインスリン様成長因子(IGF)-IとIGF結合蛋白の絶食・再給餌に対する反応
井筒彩歌, 田所大二, 羽原史織, 宇賀地優希, 清水宗敬, 日本比較内分泌学会大会及びシンポジウムプログラム・講演要旨, 45th, 2021

サクラマスにおける光周期に依存的・非依存的なスモルト化の検討
宇賀地優希, 鈴木章太郎, 高橋英佑, 崔聞達, 清水宗敬, 日本比較内分泌学会大会及びシンポジウムプログラム・講演要旨, 45th, 2021

令和元年度日本水産学会北海道支部大会
安井 肇, 木村 稔, 宮腰 靖之, 清水 宗敬, 日本水産学会誌, 86, 3, 221, 222, 15 May 2020
公益社団法人 日本水産学会, Japanese

ノルウェーとの持続的な養殖業に関するサマーコースの紹介
清水 宗敬, 日本水産学会誌, 86, 1, 33, 33, 15 Jan. 2020
公益社団法人 日本水産学会, Japanese

平成30年度日本水産学会北海道支部大会
安井 肇, 宮園 章, 栗原 秀幸, 清水 宗敬, 高橋 潤, 日本水産学会誌, 85, 2, 237, 238, 15 Mar. 2019
公益社団法人 日本水産学会, Japanese

淡水での絶食経験はシロザケ稚魚の低温海水中での成長停滞を引き起こす
清水 宗敬, 比較内分泌学, 45, 167, 82, 84, 2019
日本比較内分泌学会, Japanese

2018年春季の網走沿岸におけるサケ幼稚魚の摂餌と成長
越野陽介, 春日井潔, 中村太朗, 藤原真, 宮腰靖之, 隼野寛史, 中村周, 宮下倭麻, 工藤秀明, 清水宗敬, 日本水産学会大会講演要旨集, 2019, 2019

サケの資源変動を科学する技術開発と課題 サケ幼稚魚のリアルタイム成長評価のための技術開発
清水宗敬, 日本水産学会大会講演要旨集, 2018, 249, 26 Mar. 2018
Japanese

シロザケ稚魚における血中ホルモン量を用いた成長評価:2013‐2017年の野外調査の結果
金子信人, 虎尾充, 藤原真, 越野陽介, 宮腰靖之, 清水宗敬, 日本水産学会大会講演要旨集, 2018, 16, 26 Mar. 2018
Japanese

淡水中の摂餌状態と海水温がシロザケ稚魚の成長に与える影響の評価
中村周, 金子信人, 宮腰靖之, 清水宗敬, 日本水産学会大会講演要旨集, 2017, 133, 26 Mar. 2017
Japanese

広瀬川のサクラマス秋スモルトの浸透圧調節能と降海性
棟方有宗, 新房由紀子, 佐藤大介, 清水宗敬, 日本水産学会大会講演要旨集, 2017, 13, 26 Mar. 2017
Japanese

血中インスリン様成長因子結合蛋白‐1bを用いたシロザケ稚魚の成長評価
金子信人, 虎尾充, 藤原真, 越野陽介, 宮腰靖之, 清水宗敬, 日本水産学会大会講演要旨集, 2017, 15, 26 Mar. 2017
Japanese

サクラマスインスリン様成長因子結合蛋白‐1の機能的組換え蛋白の作製
田中英絵, 中野裕介, 水田紘子, 平松尚志, 清水宗敬, 日本水産学会大会講演要旨集, 2017, 170, 26 Mar. 2017
Japanese

シロザケ稚魚における個体成長率とインスリン様成長因子‐I血中蛋白・遺伝子発現量の関係
金子信人, 谷山奈津美, 宮腰靖之, 清水宗敬, 日本水産学会大会講演要旨集, 2016, 162, 26 Mar. 2016
Japanese

北海道太平洋東部釧路川沿岸におけるサクラマス幼魚の出現動態
實吉隼人, 大森始, 飯嶋亜内, 小山達也, 春日井潔, 宮腰靖之, 金子信人, 清水宗敬, 日本水産学会大会講演要旨集, 2016, 134, 26 Mar. 2016
Japanese

ビワマスNa⁺/K⁺‐ATPase α1bサブユニットのプロモーター領域のクローニング
志村遥夏, 中嶋拓郎, 浦和寛, 清水宗敬, 日本水産学会大会講演要旨集, 2015, 214, 27 Mar. 2015
Japanese

カラフトマス稚魚の降海回遊に伴う生理学的な成長指標の変化
金子信人, 谷山奈津美, 藤原真, 虎尾充, 宮腰靖之, 清水宗敬, 日本水産学会大会講演要旨集, 2015, 16, 27 Mar. 2015
Japanese

平成25年度日本水産学会春季大会に参加して：恩師の授賞
清水 宗敬, 比較内分泌学, 39, 149, 145, 146, 2013
日本比較内分泌学会, Japanese

Cloning of cDNA for choriogenin H and choriogenin L of masu salmon
Toshiaki Fujita, Haruhisa Fukada, Munetaka Shimizu, Naoshi Hiramatsu, Akihiko Hara, Fisheries Science, 68, 1273, 1274, 2002
English

Changes of serum growth hormone and vitellogenin levels during vitellogenesis in female masu salmon Oncorhynchus masou.
Fukada H, Hiramatsu N, Kiramura M, Shimizu M, Hara A, Fisheries Science, 66, 4, 789, 791, 2000
Japanese Society of Fisheries Science, English

Serum levels of precursors to vitelline envelop proteins (choriogenins) in Sakhalin taimen after treatment with estrogen and during oocyte growth.
Munetaka Shimizu, Haruhisa Fukada, Toshiaki Fujita, Naoshi Hiramatsu, Akihiko Hara, Journal of Fish Biology, 57, 170, 181, 2000

Immunochemical detection of vitelline envelope-related proteins in masu salmon
T Fujita, M Shimizu, A Hara, ADVANCES IN COMPARATIVE ENDOCRINOLOGY, TOMES 1 AND 2, 1487, 1491, 1997
English

卵黄蛋白前駆物質（ビテロジェニン）を指標にした成熟度判定手法の開発　　　　　　　　　　　　　　　
原彰彦, 平松尚志, 清水宗敬, 平成6年度新品種作出基礎技術開発事業研究成果の概要, 192, 203, 1995
Japanese, Technical report

AN OLFACTORY SYSTEM SPECIFIC PROTEIN IN SOCKEYE SALMON AND KOKANEE SALMON.(Physiology)Proceedings of the Sixty-Third Annual Meeting of the Zoologiacal Socistry of Japan :
Shimizu M., Kudo H., Ueda H., Kara A., Shimazaki K., Yamauchi K., Zoological science, 9, 6, 1244, 1244, 1992
Zoological Society of Japan, English

光周期調節による北海道産サクラマスのスモルト化と成熟の制御の試み
北出晴香, 高橋英佑, 林 瑞希, 清水宗敬
令和6年度日本水産学会秋季大会, 25 Sep. 2024, Oral presentation
48408472

ニジマスの組換えインスリン様成長因子結合タンパク質-2a1と-2b1の作製　　　　　　　　　　　　　　　
丑沢悠衣花, 羽原史織, 丸岡 愁, 鈴木俊太郎, Beth M. Cleveland, 清水宗敬
令和6年度日本水産学会秋季大会, 25 Sep. 2024, Poster presentation

サケ科魚類の血中インスリン様成長因子 (IGF) -2の測定法確立
井筒彩歌, 鈴木俊太郎, 田島奈緒, 清水宗敬
令和6年度日本水産学会秋季大会, 25 Sep. 2024, Poster presentation
45296193

Profiles of circulating insulin-like growth factor (IGF)-1 and IGF-binding proteins (IGFBPs) in IGFBP-2b gene-edited rainbow trout
Ayaka Izutsu, Yuika Ushizawa, Lisa M. Radler, Beth, M. Cleveland, Munetaka Shimizu
10th International Symposium on Fish Endocrinology, 17 Sep. 2024, English, Poster presentation
45296193

Utility of circulating insulin-like growth factor binding proteins as growth/stress indices in salmonids
Munetaka Shimizu, Nobuto Kaneko, Ayaka Izutsu, Miki Fukuda, Momoka Arimoto, Hanae Tanaka, Shiori Habara
10th International Symposium on Fish Endocrinology, 16 Sep. 2024, English, Oral presentation
45296193

Growth performance and expression of insulin-like growth factors (IGF) and IGF binding proteins (IGFBP) in gene edited rainbow trout lacking functional IGFBP-2b
Beth M. Cleveland, Lisa M. Radler, Ayaka Izutsu, Yuika Ushizawa, Munetaka Shimizu
10th International Symposium on Fish Endocrinolog, 16 Sep. 2024, English, Oral presentation
45296193

ニジマスの血中インスリン様成長因子(IGF)-1とIGF結合タンパクに対する育種の効果　　　　　　　　　　　　　　　
井筒彩歌, SMALL Brian C., 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2024
2024 - 2024

北海道森系サクラマス0年魚のスモルト化特性:光周期・体サイズ依存性と同調性
田島奈緒, 北出晴香, 高橋英佑, 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2024, Poster presentation
2024 - 2024, 48408472

サクラマスのインスリン様成長因子結合タンパク質の成長ホルモン分泌調節作用　　　　　　　　　　　　　　　
渡邊聡太, 三浦拓人, 磯崎泰嘉, 長谷川竜也, 井筒彩歌, 森山俊介, 棟方有宗, 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2024
2024 - 2024

サケ科魚類の血中インスリン様成長因子結合タンパク(IGFBP)-2bの検出・測定法の特性比較　　　　　　　　　　　　　　　
井筒彩歌, 羽原史織, 田所大二, 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2023
2023 - 2023

血中インスリン様成長因子-1を用いた外洋シロザケの成長評価の試み　　　　　　　　　　　　　　　
有本百花, 本多健太郎, 井筒彩歌, 浦和茂彦, DEEG Christoph M., 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2023
2023 - 2023

北海道産サクラマス0年魚における体サイズと海水適応能の発達との関係
北出晴香, 宇賀地優希, 林瑞希, 高橋英佑, 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2023, Poster presentation
2023 - 2023, 48408472

ニジマス稚魚における新規成長促進法の確立　　　　　　　　　　　　　　　
内藤佑哉, 有本百花, 清水宗敬, 宮西弘
日本水産学会大会講演要旨集(CD-ROM), 2023
2023 - 2023

サケ科魚類の血中IGF結合タンパク-2bの測定:スモルト化に伴う変化と測定系の最適化　　　　　　　　　　　　　　　
井筒彩歌, 宇賀地優希, 羽原史織, 清水宗敬
日本比較内分泌学会大会及びシンポジウムプログラム・講演要旨, 2023
2023 - 2023

ニジマスのインスリン様成長因子結合蛋白-2bのゲノム編集の効果と組換え蛋白の作製　　　　　　　　　　　　　　　
羽原史織, 及川仁, 井筒彩歌, CLEVELAND Beth M., RADLER Lisa M., 三浦拓人, 山口銀乃介, 清水宗敬
日本水産学会大会講演要旨集(CD-ROM), 2022
2022 - 2022

血中インスリン様成長因子結合タンパク-1bの存在様式　　　　　　　　　　　　　　　
有本百花, 井筒彩歌, 原彰彦, 清水宗敬
日本水産学会北海道支部大会講演要旨集, 2022
2022 - 2022

ニジマスのインスリン様成長因子（IGF）-IとIGF結合蛋白の絶食・再給餌に対する反応　　　　　　　　　　　　　　　
井筒彩歌, 田所大二, 羽原史織, 宇賀地優希, 清水宗敬
第45回日本比較内分泌学会, Poster presentation
12 Nov. 2021 - 14 Nov. 2021

サクラマスにおける光周期に依存的・非依存的なスモルト化の検討　　　　　　　　　　　　　　　
宇賀地優希, 鈴木章太郎, 高橋英佑, 崔聞達, 清水宗敬
第45回日本比較内分泌学会, Poster presentation
12 Nov. 2021

北海道産サクラマスの光周期操作に対するスモルト化時期の応答比較　　　　　　　　　　　　　　　
宇賀地優希, 鈴木章太郎, 高橋英佑, 崔聞達, 清水宗敬
令和3年日本水産学会秋季大会, Oral presentation
13 Sep. 2021 - 16 Sep. 2021

ジマスにおける生理学的な成長指標の評価　　　　　　　　　　　　　　　
井筒彩歌, 田所大二, 羽原史織, 宇賀地優希, 清水宗敬
令和3年日本水産学会秋季大会, Oral presentation
13 Sep. 2021 - 16 Sep. 2021

Assessing growth of salmon in the wild by using hormones and proteins　　　　　　　　　　　　　　　
Munetaka Shimizu
Society for Experimental Biology Annual Meeting 2021, 30 Jun. 2021
[Invited]

Physiological tools for evaluating growth status of migrating salmon　　　　　　　　　　　　　　　
Munetaka Shimizu
The Third NPAFC Virtual Workshop on Linkages between Pacific Salmon Production and Environmental Changes, 27 May 2021, Nominated symposium
[Invited]

シロザケ稚魚の成長に及ぼす降海前後の摂餌状態と低水温の影響　　　　　　　　　　　　　　　
及川 仁, 中村 周, 金子信人, 虎尾 充, 越野陽介, 清水宗敬
令和3年度日本水産学会, Oral presentation
26 Mar. 2021 - 29 Mar. 2021

クロソイ養殖の効率化に向けた補償成長に関する給餌試験　　　　　　　　　　　　　　　
芝竜太郎, 山口燿, 竹内真論, 木村和世, 平井輝孝, 川崎琢真, 清水宗敬, 東藤孝, 平松尚志
水産増殖, 2021
2021 - 2021

サクラマスの銀化に伴うインスリン様成長因子−Iの変化と鰓Na+,K+-ATPaseとの関係　　　　　　　　　　　　　　　
清水宗敬
平成24年度日本水産学会春季大会, 28 Mar. 2012, Japanese, Oral presentation
[Domestic Conference]

水産科学英語I　　　　　　　　　　　　　　　
北海道大学水産学部

北方生物圏機能生物学　　　　　　　　　　　　　　　
北海道大学水産学部

海洋生物科学I　　　　　　　　　　　　　　　
北海道大学水産学部

比較生理学　　　　　　　　　　　　　　　
北海道大学水産学部

水産科学英語II　　　　　　　　　　　　　　　
北海道大学水産学部

水産物利用学　　　　　　　　　　　　　　　
北海道大学水産学部

生化学II　　　　　　　　　　　　　　　
北海道大学水産学部

Jul. 2016 - Present
International Society for Fish Endocrinology　　　　　　　　　　　　　　　

サケ科魚類の成長調節と生活史分岐メカニズムの理解と増養殖・資源評価への展開
科学研究費助成事業
01 Apr. 2025 - 31 Mar. 2030
清水 宗敬
日本学術振興会, 基盤研究(A), 北海道大学, 25H00936

海水経験技術による回遊性水産有用魚種の成長・成熟促進機構の解明と応用
科学研究費助成事業
01 Apr. 2023 - 31 Mar. 2027
宮西 弘, 引間 順一, 清水 宗敬, 黒木 真理
サケマス類、ウナギおよびチョウザメは、日本における重要な水産有用魚種である。しかし、各魚種において天然資源の減少や国内生産量の伸び悩みといった課題がある。これを解決するために、本研究では、「海水経験法」というユニークかつ増養殖に資する新規飼育法を開発し検証することを第一の目的とする。海水経験とは、淡水飼育中の稚魚に人為的かつ一時的に塩水刺激を加えることで、淡水再馴致後の成長が顕著に促進される。申請者らは、ニホンメダカをモデルに海水経験と着想を得て、水産有用魚種である回遊性魚類のサケマス類、ニホンウナギおよびチョウザメでその効果を確認した。サケマス類は、海面養殖時に、1割程度が斃死することが知られていたが、淡水飼育時にあえて海水環境を経験にさせることで、海水適応能が上昇し斃死が減少することも見出した。しかし、なぜ成長促進されるか？は不明な点が多い。また、現行の方法では海水経験期間が長く、より簡便な方法が求められる。そこで本研究では、既存の海水経験法による初期成長促進の生理学的理解を深め、付加的価値を高めるために免疫機構への影響を明らかにする。基礎知見を基に、簡易的な改良型海水経験法の確立を目指す。本研究課題は、サケマス類における海面養殖時の斃死減少およびサイズアップ、ウナギにおける成長不良個体（ビリ）の解決、チョウザメにおける成熟期間の短縮およびキャビアの生産性向上に寄与することを目的に、この革新的新規飼育法を社会実装可能なレベルまで発展させ、国内の魚類養殖の強化に貢献する。
日本学術振興会, 基盤研究(B), 宮崎大学, 23K26989

海水経験技術による回遊性水産有用魚種の成長・成熟促進機構の解明と応用
科学研究費助成事業
Apr. 2023 - Mar. 2027
宮西 弘, 清水 宗敬, 引間 順一, 黒木 真理
日本学術振興会, 基盤研究(B), 宮崎大学, 23H02296

魚類特有の成長調節メカニズムと指標に基づく増養殖魚診断
科学研究費助成事業
01 Apr. 2022 - 31 Mar. 2026
清水 宗敬, 棟方 有宗, 森山 俊介, 内田 勝久
本研究はサケ科魚類をモデルとして、成長調節に関わる数種のホルモン・タンパク質の機能を明らかにし、それらを感度と方向性が異なる指標として組み合わせて、増養殖魚の成長とストレスを高精度で診断することを目的としている。本年度は以下の成果を得た。
インスリン様成長因子（IGF）-1と-2、およびIGF結合タンパク質（IGFBP）-2aについて大腸菌発現系を用いて組換えタンパク質の作製を行った。まず融合パートナーと共に組換えサケ（rs）IGF-1と-2を発現させた。そして、rsIGF-1と-2についてはトロンビンによる酵素処理を行って融合パートナーを切断し、逆相クロマトグラフィーにより精製した。一方、rsIGFBP-2aは融合パートナーを付けた状態でアフィニティー精製した。
ゲノム編集実験については、研究協力者が所属する米国冷水養殖研究所にて、ニジマスIGFBP-2bのF2ノックアウト（KO）F2個体を作出した。IGFBP-2b KOによる血中IGF-1や他のIGFBPの補償反応を調べたところ、変異型個体と野生型個体で明瞭な違いは認められなかった。現在、研究協力者が各組織のmRNAレベルでの反応を解析中である。
融合パートナー付きのrsIGF-2を抗原として抗血清を得た。これを用いて時間分解蛍光免疫測定系の確立を試み、スタンダードカーブを得た。
また、ニジマスを対象にして育種が進んだ系統と非育種の系統の絶食に対するIGF-1/IGFBP系の反応を調べた。結果、高成長に対する選抜育種によって血中IGF-1量のベースラインの増加と血中IGFBP-1bの反応性の減少が生じていることが示唆された。
リガンドブロッティングを用いてニホンウナギ血中IGFBPの検出を行った。結果、サケ科魚類のIGFBP-1と類似した低分離量のバンドが検出され、個体によって血中量が異なることが明らかになった。
日本学術振興会, 基盤研究(B), 北海道大学, 23K23679

魚卵アレルゲン低減化魚類の提案と最適な飼育環境の確立
科学研究費助成事業
Apr. 2023 - Mar. 2026
清水 裕, 笹岡 友季穂, 平松 尚志, 佐伯 宏樹, 清水 宗敬
日本学術振興会, 基盤研究(C), 北海道大学, 23K05125

魚類特有の成長調節メカニズムと指標に基づく増養殖魚診断
科学研究費助成事業
Apr. 2022 - Mar. 2026
清水 宗敬, 棟方 有宗, 森山 俊介, 内田 勝久
日本学術振興会, 基盤研究(B), 北海道大学, 22H02414

光周期を利用して成熟を抑制し生産性を飛躍させる魚介類養殖手法の開発
イノベーション創出強化研究推進事業
Jun. 2022 - Mar. 2025
長谷川夏樹
生物系特定産業技術研究支援センター, 開発研究ステージ, 北海道大学北方生物圏フィールド科学センター, Coinvestigator, 04016C1

太平洋サケ養殖種苗の自発的ソーティング手法ならびに適苗性評価手法の開発
科学研究費助成事業
Apr. 2021 - Mar. 2025
棟方 有宗, 清水 宗敬
太平洋サケ属等のサケ科魚類において、放流や海面養殖、河川の遊漁等に好適な種苗を稚魚の環境選好性を用いて自発的に選抜（セルフソーティング）させるとともに、選抜した種苗の性質を生理学的に評価する手法を開発するため、今年度はまず成長ホルモン（GH）の測定系を構築した。具体的には、精製したシロザケ（以下サケ）のGHをユーロピウムにて標識し、競合法による時間分解蛍光免疫測定系を構築した。これにより本研究ではインスリン様成長因子（IGF）-1、ナトリウム-カリウムATPase（NKA）活性、GH、甲状腺ホルモン、コルチゾルと言った、サケ科魚類の成長や海水適応能評価に重要な複数の生理的指標の測定が可能となった。
セルフソーティング手法の開発に関しては、サケの高温、低温選好種苗のセルフソーティング手法を開発するため、左右で水温が異なる温度勾配水槽を作成した。この水槽にサケ稚魚を収容してセルフソーティングさせたところ、高・低水温群で体サイズや肥満度が異なることが示唆された。今後、これらの2群間のGHやIGF量を比較することで、高・低水温選好群の選抜と選抜種苗の生理的評価ができると考えられた。
また今年度はニジマスの給餌量・体サイズと鰓NKA活性との関係を調べた。ニジマスを給餌量を変えて（飽食と1/2飽食）飼育したところ、飽食群において鰓NKAが高くなることが判った。また実験魚の体サイズや成長率と鰓NKAの間に正の相関があることも明らかとなった。これらの結果を踏まえると、今後、ニジマスの高成長群を選抜することで、海水適応能がより早期に発達する種苗を選抜し、海面養殖種苗の生残率の向上に反映できる可能性が示された。今後は、さらに鰓NKA活性が高い個体をセルフソーティングさせる方法の開発が期待される。
日本学術振興会, 基盤研究(C), 宮城教育大学, 21K05724

Development of techniques, systems and network for sustainable aquaculture and resource enhancement for salmon
二国間交流事業オープンパートナーシップ共同研究（ノルウェー）
Sep. 2020 - Mar. 2023
清水 宗敬, 工藤 秀明, 小泉 逸郞, 高橋 勇樹, 富安 信
日本学術振興会, Principal investigator

Mechanism-based diagnosis of growth and stress status of cultured salmonids
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2019 - Mar. 2023
清水 宗敬, 棟方 有宗, 森山 俊介, 内田 勝久
本研究は、サケ科魚類の成長に重要なインスリン様成長因子結合蛋白（IGFBP）の組換え蛋白を作製して、ゲノム編集による機能解析と免疫測定系の確立を行い、メカニズムの理解に基づいた成長・ストレスの診断法を開発することを目的としている。本年度は以下の成果を得た。
ニジマスのIGFBP-2b1と-2b2の組換え蛋白の作製を大腸菌発現系を用いて行った。まずヒスチジンタグ（His）のみを付加した組換えIGFBP-2b1と-2b2を発現させた。その後、組換えIGFBPをニッケルカラムを用いて精製した。これらの特性を解析した結果、IGFBP-2b2はIGF-1結合能を持たないことが示唆された。また、IGFBP-2b1については、蛋白質の折りたたみと溶解性を高めるチオレドキシン（Trx）とHisを付加した組換え蛋白も作製した。Trx.His.IGFBP-2b1をエンテロキナーゼ（EK）による酵素処理して融合パートナーを切断し、逆相クロマトグラフィーにより精製した。さらに、サクラマスIGF-1のTrx・His付き組換え蛋白を作製した。その際に、EK認識配列をThrombin認識配列に変えたところ、非特異的な分解が減少し、回収率が大きく向上した。この操作は組換え蛋白IGFBPにも応用可能であると考えられる。これによりmgオーダーの大量作製が期待できる。
作製・精製したニジマスIGFBP-2b1を用いて生体投与実験を行った。当初はゲノム編集魚に投与する計画であったが、コロナ禍のため実施が困難であったため、野生型ニジマス0年魚に組換え蛋白を投与した。投与により、血中IGF-1量には変化が見られなかったものの、血中IGF-1量と肥満度の間に正の相関が見られるようになった。今後、上述の方法で大量に作製した組換えIGFBP-2b1を用いて再実験を行うことで、その作用経路が明らかになると考えられる。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19H03024

Assessment of impacts of low temperature and nutritional conditions on survival of juvenile chum salmon
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
Apr. 2018 - Mar. 2021
宮腰 靖之, 虎尾 充, 清水 宗敬
異なる栄養状態と水温条件が海水移行時のサケ稚魚の初期減耗に与える影響を調べるため，2018年，水温条件と給餌・絶食の条件を変えた以下の試験群を設定してサケ稚魚の飼育試験を行った。給餌率をそれぞれ0%（絶食），1%，および3%で5日間飼育した後，それぞれの群を低水温区（4℃），中水温区（7℃），高水温区（10℃）の試験水槽に収容し，3日間の馴致期間を経て5日間の海水飼育を行った。
これらの試験群について，栄養状態の指標として筋肉中のトリグリセリド（TG）含量と肝臓中のグリコーゲン含量を測定した。成長率の指標として血中のインスリン様成長因子-I（IGF-I）量を測定した。海水飼育後のTG含量はいずれの水温区でも淡水飼育時の給餌率が高い群でTG量は高く，肝臓中グリコーゲン含量は高水温・絶食群で高い傾向がみられた。血中IGF-I量は淡水での絶食には差は無かったが，海水馴致時にはいずれの水温でも絶食群でIGF-I濃度が低かった。海水飼育後は絶食による違いはなく，高水温群でIGF-Iが高くなった。
遊泳力の指標として臨界遊泳速度（Ucrit）を測定した。海水飼育後には，低水温試験群の遊泳速度は高水温試験群より有意に低かった。サケ稚魚の海水移行後の遊泳速度は水温に大きく影響を受け，低水温では遊泳速度が低下することが示された。また，淡水生活期の絶食が海水移行後の遊泳速度低下につながることも示されたが，水温が高い場合はその影響が軽減される可能性がある。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido Research Organization, 18K05801

Control of the quality of juvenile salmon for aquaculture through integrating genetic and environmental factors　　　　　　　　　　　　　　　
二国間交流事業オープンパートナーシップ共同研究（ノルウェー）
Aug. 2018 - Jul. 2020
清水 宗敬, 工藤 秀明, 小泉 逸郞, 金子 信人, 他4名
日本学術振興会, Principal investigator

サケ科魚類の新しい成長･ストレス診断法の開発と海面養殖への応用　　　　　　　　　　　　　　　
科学研究費補助金(基盤研究(B))
Apr. 2016 - Mar. 2020
清水 宗敬, 森山 俊介, 棟方 有宗, 内田 勝久
文部科学省, Principal investigator, Competitive research funding

Clarification of physiological mechanism of fall smoltification in Pacific salmon and its application for screening of seedlings
Grants-in-Aid for Scientific Research
Apr. 2015 - Mar. 2019
Munakata Arimune, Shimizu Munetaka, Yada Takashi, Hiroi Junya, Schreck Carl, Noakes David
In general, Pacific salmon such as masu and Chinook salmon undergo smoltification and seaward migration in spring. Recently, however, some populations show such phenomena in fall. According to our studies, fall smolt masu salmon show high plasma thyroid hormone levels as well as spring smolt, suggesting that fall smolt undergo the smoltification using same physiological mechanisms. Since fall smolt masu salmon showed high growth rate, it is also suggested that growth system modulate early smoltification. In Chinook salmon, furthermore, fall smolts exhibited high levels of plasma cortisol levels and HSP70 gene expression in the liver against water temperature decrease and increase. Based on these results, its is indicated that water temperature changes modulate early smoltification. We also developed the selection methods of fall smolts by use of hatchery cultured juvenile masu and Chinook salmon.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Miyagi University of Education, 15K07572

Development of new aquaculture protocols for salmon through understanding smoltification process　　　　　　　　　　　　　　　
二国間交流事業オープンパートナーシップ共同研究（ノルウェー）
Oct. 2015 - Sep. 2017
清水 宗敬, 棟方 有宗, 廣井 準也
日本学術振興会, Principal investigator

Evaluation of growth rates of juvenile chum and pink salmon in their early marine phase using the physiological and ecological techniques
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
01 Apr. 2013 - 31 Mar. 2016
MIYAKOSHI Yasuyuki, SHIMIZU Munetaka, TORAO Mitsuru
To evaluate the growth rates of chum and pink salmon in their early marine life, we analyzed the otolith daily increments of juvenile chum and pink salmon and examined the effective physiological indicators for growth rates. By otolith increment analyses, the dates of ocean entry and daily growth rates can be estimated. From examining the physiological indicators, the serum insulin-like growth factor (IGF)-I can be used as a most useful indicator to evaluate the growth rates of juvenile salmon. Serum IGF-I levels in chum and pink salmon estuarine area were lower and fish in the coastal area were higher, indicating that growths of juvenile salmon was activated when they left the estuarine area and migrated to the offshore while fish of low growth stay in the estuary. Until May, IGF-I levels in pink salmon were lower than chum salmon but were higher in June, which likely reflects a higher growth rate of this species.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido Research Organization, 25450289

Production of recombinant salmon insulin-like growth factor binding proteins
Grants-in-Aid for Scientific Research
2012 - 2012
SHIMIZU Munetaka, ANDO Hironori
The present study dealt with production of functional recombinant insulin-like growth factor binding proteins (IGFBPs) that are important regulators of IGFs. We first established a primary pituitary cell culture for immature masu salmon. We next expressed recombinant IGFBP-1a and -1b using bacterial cell system. These recombinant IGFBPs were added to the pituitary cell culture to look at how the inhibitory action of IGF-I on GH release was modulated. The result suggests that although salmon IGFBP-1a and -1b were believed to be inhibitors of IGF-I actions, they actually enhanced the action of IGF-I on the pituitary. Availability of recombinant protein will be extremely useful to further analyze functions of fish IGFBPs.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 24580256

Quantification of insulin-like growth factor binding proteins in salmon
Grants-in-Aid for Scientific Research
2009 - 2011
SHIMIZU Munetaka
The present study established time-resolved fluoroimmunoassay and real-time quantitative PCR for salmon insulin-like growth factor (IGF)-I and an IGF-binding protein (IGFBP-1b). Feeding and fasting experiment using individually-tagged masu salmon revealed that IGF-I and IGFBP-1b generally show positive and negative correlations with growth rate, respectively. The present study suggests that these components are useful as growth indices in salmon.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 21580214

成長のメカニズムに着目した魚のストレス診断法の開発
産学が連携した研究開発成果の展開 研究成果展開事業 研究成果最適展開支援プログラム(A-STEP) 探索タイプ
2010 - 2010
清水 宗敬
本研究は、魚類のストレスの指標として有望であるが未同定の、28 kDa インスリン様成長因子結合蛋白(28K BP)について、サケ科魚類でタイプを同定することを目標とした。まず、精製品の部分アミノ酸配列から縮重プライマーを設計した。そしてPCR法により翻訳領域部分を含む28K BPのcDNAを初めてクローニングした。その配列はIGFBP-1に最も高い相同性を示した。一方、サケでは22K BPがIGFBP-1とされていたが、28K BPとともに遺伝子の重複により派生したものであることが分かった。両者はストレスホルモンであるコルチゾルにより誘導されたことから、ストレスの指標として有用であると考えられた。
北海道大学

Identification of circulating IGF-binding proteins in salmon
Grants-in-Aid for Scientific Research(基盤研究(C))
2007 - 2008
Munetaka SHIMIZU
魚類を含む脊椎動物の成長には、インスリン様成長因子(insulin-like growth factor, IGF)-Iが重要な役割を果たしている。しかし、IGF-Iの活性は6種類のIGF結合蛋白(IGF-binding protein, IGFBP)によって厳密に調節されている。これらのIGFBPの機能はタイプにより異なるが、大まかにIGF-Iを介した成長の「促進型」と「阻害型」に分けられる。サケ科魚類の血中には少なくとも3種類のIGFBPが検出されるが、それぞれがどのタイプに相当するのかは非常に混乱している。本研究はこれらのIGFBPの同定を行って上述の混乱を解決することを目的としている。まず、サケ科魚類の血中IGF-Iの主要な運搬役であり、成長の「促進型」と考えられている41 kDa IGFBP(41K BP)およびIGFBP-3のcDNAクローニングを行った。クローニングにより得られた配列を解析したところ、41K BPはIGFBP-2に最も高い相同性を示した。一方、IGFBP-3の配列は、41K BPのものとは異なっていた。このことから、41K BPはIGFBP-3ではなくIGFBP-2であることが明らかになった。さらにもう一種類のIGFBPをクローニングすると共に、これらの発現解析を行った。新たに得られたIGFBPの演繹アミノ酸配列はIGFBP-2に最も近かった。ま...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 北海道大学, Principal investigator, Competitive research funding, 19580198

サケ科魚類の河川生活期における相分化機構に関する免疫生化学的研究
科学研究費助成事業 特別研究員奨励費
1999 - 1999
清水 宗敬
日本学術振興会, 特別研究員奨励費, 北海道大学, 97J01222

北海道と世界の”サーモン”　　　　　　　　　　　　　　　
26 Oct. 2024
Lecturer
Lecture
千歳水族館
その”サーモン”どこからきたの？2024

マリンラーニングセミナー　　　　　　　　　　　　　　　
Aug. 2023
Lecturer
Lecture
日本財団・海と日本Project

サケ　　　　　　　　　　　　　　　
19 Oct. 2022
Advisor
Media report
NHK
ギョギョッとサカナ☆スター

マリンラーニングセミナー　　　　　　　　　　　　　　　
Aug. 2022
Lecturer
Lecture
日本財団・海と日本Project

マリンラーニングセミナー　　　　　　　　　　　　　　　
02 Oct. 2021
Lecturer
Lecture
日本財団・海と日本Project

何が違う？鮭 サーモン 鱒　　　　　　　　　　　　　　　
20 Nov. 2020
Contribution
Paper
東京新聞

マリンラーニングセミナー　　　　　　　　　　　　　　　
Aug. 2018
Lecturer
Lecture
日本財団・海と日本Project

マリンラーニングセミナー　　　　　　　　　　　　　　　
Jul. 2017
Lecturer
Lecture
日本財団・海と日本Project