Study on the Mechanism of the Blood-Glucose-Lowering Effect of Collagen Peptides from Sturgeon By-Products     

Yukiho Sasaoka  Taichi Takagi  Shunta Michiba  Yohei Yamamoto  Yuya Kumagai  Hideki Kishimura 《Marine drugs》2021,19(10)

In a previous study, we found that the collagen peptides prepared from the by-products of Bester sturgeon had an inhibitory effect on elevated blood glucose levels in a glucose tolerance test with ICR mice. In the present study, we examine the mechanism of the effect of sturgeon collagen peptides (SCPs) in detail. When glucose was orally administered to mice along with the SCPs, it was found that the glucose remained in the stomach for a longer time. In the above tests, the amount of glucose excreted in the feces of mice also increased. On the contrary, it was revealed that the SCPs have a dipeptidyl-peptidase-IV (DPP-IV) inhibitory ability in an in vitro test. In subsequent oral and intravenous glucose administration tests, glucagon-like peptide-1 (GLP-1) and insulin levels in the blood of mice were maintained at high levels. These results suggested the following three mechanisms: SCPs slow the rate of transportation of glucose from the stomach into the small intestine, resulting in delayed glucose absorption; SCPs suppress the absorption of glucose in the small intestine and excrete it from the body; SCPs inhibit DPP-IV in the blood and maintain a high GLP-1 level in blood, which in turn stimulates insulin secretion.  相似文献   

Effects of manufacturing factors on the viscosity of a polysaccharide solution extracted from Gagome Kjellmaniella crassifolia     

Shigeru Katayama  Toshihiro Nishio  Zensuke Iseya  Hideki Kishimura  Hiroki Saeki 《Fisheries Science》2009,75(2):491-497

A highly viscous polysaccharide solution was extracted from Gagome Kjellmaniella crassifolia in 20°C water. The eluted sugar concentration was 0.16%, and the extracted carbohydrates consisted of fucoidan, laminaran, and alginate at an approximately ratio of 8.2:0.8:1.0. An increase in the extraction temperature resulted in a less viscous solution, even though the amount of eluted sugar was higher than that obtained at a lower temperature. The most viscous extraction solution was obtained at a neutral pH, with a more acidic or alkaline extraction solution being a less viscous. When the highly viscous polysaccharide solution was heated, the viscosity decreased markedly with increasing temperature. The viscosity of the polysaccharide solution increased after dialysis against water and decreased with the addition of either KCl or NaCl. However, the viscosity was recovered to previous levels by following re-dialysis against water. The removal of divalent cations by EDTA and the re-addition using CaCl₂ or MgCl₂ also caused reversible changes to the viscosity. These characterizations will be useful for widespread applications of viscous K. crassifolia polysaccharides.  相似文献   

Treatment of autoimmune neuroinflammation with a synthetic tryptophan metabolite   总被引：1，自引：0，他引：1  

Platten M  Ho PP  Youssef S  Fontoura P  Garren H  Hur EM  Gupta R  Lee LY  Kidd BA  Robinson WH  Sobel RA  Selley ML  Steinman L 《Science (New York, N.Y.)》2005,310(5749):850-855

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A long-term observation for ecology of pathogenic Yersinia in wild rodents living in Fukushima Prefecture,Japan     

Thi Hien BUI  Khanh Thuan NGUYEN  Shunsuke IKEUCHI  Haruka YANAGAWA  Yomogi SATO  Thi Hong To TRAN  Minato OKUMURA  Takeshi NIWA  Takahide TANIGUCHI  Hideki HAYASHIDANI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1790

From 2012 to 2021, prevalence of pathogenic Yersinia in wild rodents captured in Fukushima Prefecture, Japan was investigated twice a year to clarify the ecology of this pathogen in wild rodent populations. Pathogenic Yersinia enterocolitica O8 was isolated from 13 (1.7%) of 755 wild rodents. The Y. enterocolitica O8 isolates harbored three virulent genes (ail, fyuA, and virF). This pathogen was isolated repeatedly from wild rodents in April 2015, 2016, and 2017, in June and November 2020, and in April 2021, which was 6 of 19 times of observations. All Y. enterocolitica O8 isolates showed the same PFGE patterns. These results indicated that the same clone of pathogenic Y. enterocolitica O8 has been maintained in wild rodent populations in Fukushima Prefecture. Therefore, wild rodent populations contribute substantially to the continuous transmission of Y. enterocolitica O8 and its persistence in the ecosystem. This is the first report on the isolation of pathogenic Y. enterocolitica O8 in wild rodents in Fukushima Prefecture, Japan.  相似文献   

Factors Influencing Early Survival and Growth of Laboratory‐reared Pacific Bluefin Tuna,Thunnus orientalis,Larvae          下载免费PDF全文

Yosuke Tanaka  Kazunori Kumon  Kentaro Higuchi  Takeshi Eba  Akefumi Nishi  Hideki Nikaido  Satoshi Shiozawa 《Journal of the World Aquaculture Society》2018,49(3):484-492

The collection of fertilized eggs for mass culture of Pacific bluefin tuna (PBT) relies on the spontaneous spawning of broodstock in captivity, and the spawning season of the broodstock is generally from mid‐May to September. The diameter of fertilized eggs from the broodstock decreases during the spawning season. To investigate the influence of three potential factors, the egg diameter (larger or smaller), the rearing water temperature (25 or 28 C), and the aeration rate during the night (strong or weak), on early survival and on growth of PBT larvae, replicate trials were conducted to assess these three factors until 7 d after hatching (d.a.h.). At 7 d.a.h., survival rates of larvae reared with strong nighttime aeration were found by a three‐way ANOVA to be significantly higher than for larvae reared with weak aeration. Furthermore, growth rates of PBT larvae hatched from larger eggs were significantly faster than those from smaller eggs. However, a significant difference in the survival rate was not detected for the factors, egg diameter and rearing water temperature. The results indicate that rearing with strong nighttime aeration significantly improved the early survival of PBT larvae and the egg diameter (a proxy for egg quality) and influenced growth.  相似文献   

Onset of individual growth difference in larviculture of Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis> using fertilized eggs obtained from one female     

Takayuki Takebe  Takeo Kurihara  Nobuaki Suzuki  Kentaro Ide  Hideki Nikaido  Yosuke Tanaka  Satoshi Shiozawa  Hitoshi Imaizumi  Shukei Masuma  Yoshitaka Sakakura 《Fisheries Science》2012,78(2):343-350

We conducted a rearing experiment on Pacific bluefin tuna (PBT) larvae, which originated from one female broodstock, and determined the growth history of the larvae to clarify when the growth difference occurs. We investigated the otolith microstructure of the PBT larvae to examine the individual growth history and to predict the age and body size at the onset of individual growth difference. Since total length (TL) of fish can be back-calculated from otolith radius, we back-calculated TLs of 100 fish of 19 days post hatch (dph) divided into three size groups (small, intermediate, large). Growth difference was recognized from 3 dph (mouth opening), and the difference became larger thereafter. Growth of large-size fish was assumed to be promoted by the feeding conditions of PBT larvae.  相似文献   

Single spaghetti tagging as a high-retention marking method for Japanese common sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>     

Takumi Fujino  Hideki Sawada  Hiromichi Mitamura  Reiji Masuda  Nobuaki Arai  Yoh Yamashita 《Fisheries Science》2017,83(3):367-372

Populations of sea cucumbers, including the Japanese common sea cucumber Apostichopus japonicus, have been seriously depleted worldwide due to overfishing. Mark–recapture study is an efficient means of collecting ecological data. However, the use of such a method in sea cucumbers is difficult because they lack hard tissues in the body wall. Here we tested the viability of various tagging methods on A. japonicus. First, we applied conventional tags using four different methods [single spaghetti (T-bar) tagging, double spaghetti tagging, ribbon tagging, and Atkins tagging] to ten individuals per method in aquaria for 14 days. Of the methods used, single spaghetti tagging had the highest retention rate. Then we examined the retention rate of single spaghetti tags on ten individual sea cucumbers for up to approximately 6 months in rearing conditions. The single spaghetti tagging method showed a retention rate of 100% over at least 7 days, and 50% of the tags remained embedded after 56 days. The longest duration of tag retention was 174 days, at which time the experiment was terminated. These results indicate that single spaghetti tagging is reliable for both short- and longer-term studies, making it a useful tool for ecological and conservation studies in sea cucumbers.  相似文献   

Decreasing dietary lipids improves larval survival and growth of Japanese eel Anguilla japonica     

Hirofumi Furuita  Koji Murashita  Hiroyuki Matsunari  Takeshi Yamamoto  Jiro Nagao  Kazuharu Nomura  Hideki Tanaka 《Fisheries Science》2014,80(3):581-587

Shark eggs-based diet is the only diet by which eel larvae can grow to glass eels in captivity. However, the high level of lipids in the diet is suggested to negatively affect eel larvae. This paper examines the effect of defatted shark eggs (DSE) and hen egg yolk (HY) on growth and survival of larvae of Japanese eel Anguilla japonica. Lyophilized shark egg and commercial HY were defatted with n-hexane, and four experimental diets were prepared using both defatted and untreated shark eggs and HY. Larvae were reared for 3 weeks by feeding the experimental diets. The highest survival rate was observed in the larvae fed DSE, and larvae fed HY showed the lowest survival rate. The best growth was found in larvae fed DSE, followed by shark eggs and defatted HY, and the worst growth was in HY-fed larvae. These results show that decreasing dietary lipids improves the nutritional value of both shark eggs and HY for eel larvae. Regulation of the dietary lipid level may positively affect the larval performance of eels by combination of ingredients with a low lipid content.  相似文献   

Community and trophic structures of abalone <Emphasis Type="Italic">Haliotis diversicolor</Emphasis> habitat in Sagami Bay,Japan     

Nam -Il Won  Tomohiko Kawamura  Toshihiro Onitsuka  Jun Hayakawa  Satoshi Watanabe  Toyomitsu Horii  Hideki Takami  Yoshiro Watanabe 《Fisheries Science》2007,73(5):1123-1136

Abstract:   The community and trophic structures of the subtidal habitat of the abalone Haliotis diversicolor were examined in Nagai, Sagami Bay, Japan. Conventional community indices showed no significant differences among three sampling stations. The overall continuum of stable isotope ratios was structured into three different trophic linkages: (i) brown algae-dependent benthic food chain; (ii) red algae-dependent benthic food chain; and (iii) planktonic food chain. Brown algae and red algae likely play different roles with respect to carbon sources in the habitat. Conventional fractionation values indicated that the abalone H. diversicolor (δ¹³C = −12.4 ± 1.0‰, δ¹⁵N = 9.3 ± 0.5‰) feeds on the lamina of Undaria pinnatifida during juvenile and adult stages (8.0–65.6 mm shell length). Stable isotope signatures suggested that the juveniles of other abalone species as well as some amphipods and a sea cucumber Holothuria decorata are competitors of H. diversicolor , whereas some Muricidae gastropods such as Thais bronni and Ergalatax contractus are predators. The isotopic differences among macroalgal species and the subsequent transfer to consumers indicate that stable isotopic analysis is an effective means of studying food webs in an open rocky shore community with little influence from external primary production such as terrestrial vegetation.  相似文献   

Purification of gonadotropins (PmGTH I and II) from red seabream (Pagrus major) and development of a homologous radioimmunoassay for PmGTH II     

Hideki Tanaka  Hirohiko Kagawa  Koichi Okuzawa  Keiji Hirose 《Fish physiology and biochemistry》1993,10(5):409-418

Two gonadotropic glycoproteins (PmGTH I and II) were purified by ion-exchange chromatography, gel filtration and preparative SDS-PAGE, from pituitaries of red seabream, a marine teleost which has an asynchronous-type ovary and spawns almost daily during the spawning season. The glycoproteins were composed of distinct subunits and the molecular weights were estimated to be 32 and 38 kDa for PmGTH I and PmGTH II, respectively. Both PmGTH I and II were active in two homologous bioassays: in vitro oocyte maturation and/or in vitro estradiol-17 production assays. These two GTHs were distinct in electrostatic properties, molecular weight, stability and yields from pituitaries during the spawning season. These properties suggest that PmGTH I and II correspond to salmon GTH I and II, respectively.A homologous radioimmunoassay with which to measure PmGTH II was developed using a rabbit antiserum against the subunit of PmGTH II and intact PmGTH II as standards and radioactive competitors. Competition curves for red seabream plasma and pituitary extract were parallel to the standard curve, while PmGTH I had low cross-reactivity (3.1 %) with the antibody. This specific RIA system showed an in vivo LHRHa induced GTH surge in the plasma of female red seabream.  相似文献