Hokkaido University Collection of Scholarly and Academic Papers
(65.354 recursos)
HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.
Mostrando recursos 1 - 20 de 2.167
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Occurrence of Conjugated Linolenic Acids in Purified Soybean Oil - Kinami, Tomohisa; Horii, Naoto; Narayan, Bhaskar; Arato, Shingo; Hosokawa, Masashi; Miyashita, Kazuo; Negishi, Hironori; Ikuina, Junichi; Noda, Ryuji; Shirasawa, Seiichi
A high-performance liquid chromatographic (HPLC) method is described for the determination of conjugated linoleic acids (CLA) and conjugated linolenic acids (CLN). Methyl esters prepared from purified lipid fractions of soybean oil were analyzed using an HPLC system equipped with photodiode-array detector to detect peaks having maximum absorption around 233 and 275 nm. These peaks were concentrated by AgNO3-silicic acid column chromatography and reversed-phase HPLC. The structural analysis, of dimethyloxazoline (DMOX) derivatized methyl esters, using gas chromatography–mass spectrometry (GC–MS) showed the occurrence of 9,11- and 10,12-CLA and 8,10,13-, 8,10,12-, and 9,11,13-CLN. The comparison of these conjugated fatty acids with authentic isomers...
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NEMURO : a lower trophic level model for the North Pacific marine ecosystem - Kishi, Michio J.; Kashiwai, Makoto; Ware, Daniel M.; Megrey, Bernard A.; Eslinger, David L.; Werner, Francisco E.; Noguchi-Aita, Maki; Azumaya, Tomonori; Fujii, Masahiko; Hashimoto, Shinji; Huang, Daji; Iizumi, Hitoshi; Ishida, Yukimasa; Kang, Sukyung; Kantakov, Gennady A.; Kim, Hyun-cheol; Komatsu, Kosei; Navrotsky, Vadim V.; Smith, S. Lan; Tadokoro, Kazuaki; Tsuda, Atsushi; Yamamura, Orio; Yamanaka, Yasuhiro; Yokouchi, Katsumi; Yoshie, Naoki; Zhang, Jing; Zuenkou, Yury I.; Zvalinsky, Vladimir I.
The PICES CCCC (North Pacific Marine Science Organization, Climate Change and Carrying Capacity program) MODEL Task Team achieved a consensus on the structure of a prototype lower trophic level ecosystem model for the North Pacific Ocean, and named it the North Pacific Ecosystem Model for Understanding Regional Oceanography, “NEMURO”. Through an extensive dialog between modelers, plankton biologists and oceanographers, an extensive review was conducted to define NEMURO's process equations and their parameter values for distinct geographic regions. We present in this paper the formulation, structure and governing equations of NEMURO as well as examples to illustrate its behavior. NEMURO has...
3.
Characterization of molecular species of collagen in scallop mantle - Shen, Xuan Ri; Kurihara, Hideyuki; Takahashi, Koretaro
Pepsin-solubilized collagen (SMPC) extracted from scallop mantle was first subjected to amino acid analysis and molecular weight determination. The SMPC was rich in hydroxylysine. After salting out, the SMPC showed two different profiles in molecules, amino acids and peptide maps. The two different collagen molecules had different uronic acid contents and gel-forming abilities. SMPC may be applicable to a variety of usage, including functional foods.
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Feeding habits of stone flounder Platichthys bicoloratus larvae in Mutsu Bay, Japan - Takatsu, Tetsuya; Suzuki, Yuusuke; Shimizu, Akiko; Imura, Kazuo; Hiraoka, Yuko; Shiga, Naonobu
To clarify the feeding strategy of pelagic larvae of stone flounder in Mutsu Bay, the dietary composition and prey size was investigated from February to April during 1989–1999. Diets were compared with the numerical and volumetric compositions and frequency of occurrence of each prey species. Mensuration formulae were applied to estimate individual prey volume in the diet, while the length of planktonic species was measured from net and water samples. Prey shapes were assumed as sphere, cylinder, ellipsoid, pyramid, two elliptical cones, or a combination of ellipsoid and cylinder. Prey-size range increased as the larvae grew. Preflexion larvae fed mainly...
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Annual variation of potential predation impacts on larval and juvenile marbled sole Pseudopleuronectes yokohamae by sand shrimp Crangon uritai in Hakodate Bay, Hokkaido - NAKAYA, Mitsuhiro; TAKATSU, Tetsuya; JOH, Mikimasa; NAKAGAMI, Masayasu; TAKAHASHI, Toyomi
An investigation was conducted to evaluate the annual variation in potential predation impact (PPI) on larval and juvenile Pseudopleuronectes yokohamae by Crangon uritai in Hakodate Bay using predator–prey size relationships. Laboratory experiments were designed to estimate the favorable prey size of C. uritai through back-calculation of body length (BL) of P. yokohamae from sagittal otolith diameter observed in the stomachs of C. uritai. The most favorable prey–predator size ratio (BL of P. yokohamae–total length (TL) of C. uritai) class was 0.15–0.19, and ranged from 0.12–0.31. There was a significant positive correlation between the BL increase of P. yokohamae and the...
13.
Maternal effects and larval survival of marbled sole Pseudopleuronectes yokohamae - Higashitani, Tomomi; Takatsu, Tetsuya; Nakaya, Mitsuhiro; Joh, Mikimasa; Takahashi, Toyomi
Maternal effects of animals are the phenotypic influences of age, size, and condition of spawners on the survival and phenotypic traits of offspring. To clarify the maternal effects for marbled sole Pseudopleuronectes yokohamae, we investigated the effects of body size, nutrient condition, and growth history of adult females on egg size, larval size, and starvation tolerance, growth, and feeding ability of offspring. The fecundity of adult females was strongly dependent on body size. Path analysis revealed that the mother's total length positively affected mean egg diameter, meaning that large females spawned large eggs. In contrast, the relative growth rate of...
14.
ソウハチに対する刺網の網目選択性 - 若山, 賢一; 藤森, 康澄; 板谷, 和彦; 村上, 修; 三浦, 汀介
ソウハチに対する網目選択性を求めるために，8 種類の目合で構成される底刺網を用いて，北海道石狩湾において漁獲実験を行った。選択性曲線の推定には SELECT モデルを用いた。ソウハチの全漁獲尾数は 957 尾で，選択性の推定には絡みによる漁獲を除いたデータを用いた。選択性曲線として正規，対数正規，二峰性正規の 3 種類の関数を適用し，最尤法によりパラメータと相対漁獲強度を推定した。各関数のうち，二峰性正規の適合度が最も高く，同選択性曲線において最大値を得る目合相対体長（体長/目合）は 1.87 と推定された。Fishing experiments were carried out in Ishikari Bay, Hokkaido using a
bottom gillnet with eight different mesh sizes to estimate the mesh
selectivity for pointhead flounder Cleisthenes pinetorum . A total of 957
pointhead flounder were caught. The SELECT analysis with maximum
likelihood method was used to fit the different functional models, the
normal, lognormal, and bi-normal model. The catch data except for
entangling catch was used for calculation. The bi-normal model was found
to fit the data best. For the selectivity curve on the bi-normal model, the
relative length (the ratio of fish length to mesh size) with...
15.
Factors affecting egg predation in Black-tailed Gulls - Kazama, Kentaro
In colonial seabirds, nesting density, egg-laying date and nest microhabitat affect the probability of eggs being taken by avian predators. Jungle Crows (Corvus macrorhynchos) are dominant predators of eggs of Black-tailed Gulls (Larus crassirostris). Factors affecting the probability of gulls allowing the crows to attack their nests or depredate their eggs and the probability of eggs being taken were studied by direct observation and egg census, respectively. The effect of vegetation heights, position in the colony, egg-laying date and neighbour nests on the probability of eggs being taken were examined at multiple spatial scales. Gull nests were depredated more easily...
16.
Respiration in marine pelagic copepods: a global-bathymetric model - Ikeda, Tsutomu; Sano, Fumikazu; Yamaguchi, Atsushi
Historical global respiration datasets of epipelagic copepods and recent bathymetric respiration datasets of mesopelagic, upper- and lower bathypelagic and abyssopelagic copepods were combined to build a global-bathymetric respiration model by adopting two regression models (theoretical and empirical ones). Designated independent variables including body mass (expressed as dry mass, carbon or nitrogen), habitat temperature, ambient oxygen saturation and the depth of occurrence were all significant, accounting 72-80% in the variation in these respiration data. Both theoretical and empirical regression models yielded similar results, but the latter was sensitive to the choice of body mass. The mechanisms for the negative effect of...
17.
Evolutionary significance of prenuptial molting in female Pagurus hermit crabs - Wada, Satoshi; Ito, Atsushi; Mima, Azusa
Molting and breeding entail major energetic costs for female crustaceans. However, females of some hermit crabs perform a molt immediately prior to copulation (prenuptial molt). The evolutionary significance of the prenuptial molt was examined in Pagurus hermit crabs, and two hypotheses were tested: (1) prenuptial molt might enhance the success of the present clutch by cleaning the pleopods of females and thereby preventing eggs from being dislodged from the pleopods, and (2) prenuptial molt might function for growth and increase future fecundity at the cost of energetic expenditure on the present brood. Although these hypotheses are not mutually exclusive, our...
18.
Comparative study on enzymatic characteristics of trypsins from the pyloric ceca of yellow tail (Seriola quinqueradiata) and brown hakeling (Physiculus japonicus) - KISHIMURA, HIDEKI; TOKUDA, YUSUKE; KLOMKLAO, SAPPASITH; BENJAKUL, SOOTTAWAT; ANDO, SEIICHI
Trypsins from the pyloric ceca of two fish species, yellow tail (Seriola quinqueradiata) and brown hakeling (Physiculus japonicus) were purified by a series of chromatographic separations. Purity increased 62- and 106-fold with approximately 55 and 10% yield for yellow tail trypsin and brown hakeling trypsin, respectively. Final enzyme preparations were homogeneous in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the molecular weights of both enzymes were estimated to be 24 kDa by SDS-PAGE. Yellow tail and brown hakeling trypsins had maximal activity at pH 8.0 for hydrolysis of Nα-p-tosyl-L-arginine methyl ester hydrochloride and was unstable at acidic pH. The optimum...
20.
Geographic variation in a predator-induced defense and its genetic basis - Kishida, Osamu; Trussell, Geoffrey C.; Nishimura, Kinya
Predator-induced morphological defenses are a well-known form of phenotypic plasticity, but we continue to have a limited understanding of geographic variation in these responses and its genetic basis. Here we examine genetic variation and geographic differentiation in the inducible defenses of tadpoles (Rana pirica) in response to predatory salamander larvae (Hynobius retardatus). To do so, we crossed male and female frogs from a “mainland” Japanese island having predaceous salamanders and a more isolated island not having predaceous salamanders and raised resulting offspring in the presence and absence of H. retardatus. Mainland tadpoles exhibited a higher capacity to express the inducible...
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