Hokkaido University Collection of Scholarly and Academic Papers
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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 1.441
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Advances in Alstroemeria Biotechnology - Hoshino, Yoichiro
The genus Alstroemeria belongs to the family Alstroemeriaceae and comprises many ornamental species. This genus, including more than 60 species, is indigenous to South America. Thus far, numerous cultivars, which are used as cut flowers and potted plants worldwide, have been produced by interspecific hybridization and mutation breeding. Recently, biotechnological approaches are being applied in order to improve Alstroemeria strains. Interspecific hybrid plants have been produced by ovule cultures. By improving certain culture techniques, sexual incompatibility was overcome in some cross combinations using ovule cultures. Plant regeneration systems that involved the use of explants, immature ovules, leaves, etc., through callus...
2.
Inheritance of the concentration of water-soluble carbohydrates and its relationship with the concentrations of fibre and crude protein in herbage of cocksfoot (Dactylis glomerata L.) - Sanada, Y.; Takai, T.; Yamada, T.
The concentration of water-soluble carbohydrates (WSC) of cocksfoot is lower than that of other temperate grasses. Increasing in the WSC concentration in cocksfoot is important in increasing its digestibility and preference by ruminants. The genetic variation in mono- and disaccharides, fructans and total WSC concentrations and their interrelationships with crude protein (CP) and fibre concentrations of cocksfoot (Dactylis glomerata L.) at the vegetative growth stage in half-sib cross populations were assessed in two experiments conducted under spaced-planting and sward conditions. There was a wide range in the means for concentrations of fructan, WSC and neutral-detergent fibre (NDF) in parents and...
4.
Developmental biotechnology for aquaculture, with special reference to surrogate production in teleost fishes - Yamaha, Etsuro; Saito, Taiju; Goto-Kazeto, Rie; Arai, Katsutoshi
This review introduces surrogate production as a new technique for fish-seed production in aquaculture. Surrogate production in fish is a technique used to obtain the gametes of a certain genotype through the gonad of another genotype. It is achieved by inducing germ-line chimerism between different species during early development. Primordial germ cells (PGCs) are the key material of this technique to induce germ-line chimera. In several species, it has been reported that PGCs differentiated from the blastomeres inherited some maternally supplied mRNA located in the terminal regions of the early cleavage furrows. PGCs from donor species (or strains) are isolated...
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Isolation of Individual Egg Cells and Zygotes in Alstroemeria Followed by Manual Selection with a Microcapillary-connected Micropump - HOSHINO, Yoichiro; MURATA, Naho; SHINODA, Koichi
Aims: To develop a procedure for isolating living egg cells and zygotes from Alstroemeria ovules. Scope: We attempted to isolate egg cells and zygotes from the ovules of Alstroemeria aurea. The ovules were histologically observed using a clearing procedure which revealed the localization and sizes of the embryo sacs and egg apparatus within the ovules. For the isolation of egg cells, ovules were cut into sections with a surgical blade and treated with an enzyme solution. Subsequently, these ovule sections were dissected using a glass needle under an inverted microscope. Egg cells successfully isolated by this procedure were collected using...
7.
Olfactory Discriminating Ability of Lacustrine Sockeye and Masu Salmon in Various Freshwaters - Sato, Koji; Shoji, Takayuki; Ueda, Hiroshi
In order to study the olfactory discriminating ability of lacustrine sockeye salmon (Oncorhynchus nerka) and masu salmon (O. masou), the integrated olfactory nerve response to various freshwaters was recorded by electrophysiological techniques. In both species independent of sex and gonadal maturity, each freshwater caused a different olfactory response. Source and effluent waters of the culture pond at Toya Lake Station (the source and culture pond waters) evoked the minimum and maximum response magnitude, respectively. In cross-adaptation experiments, the culture pond water abolished all secondary responses to other freshwaters, and no freshwater abolished the secondary response to the culture pond water....
8.
Micro Data Logger Analyses of Homing Behavior of Chum Salmon in Ishikari Bay - Kitahashi, Takashi; Ando, Hironori; Urano, Akihisa; Ban, Masatoshi; Saito, Seiichi; Tanaka, Hideji; Naito, Yasuhiko; Ueda, Hiroshi
The profile of homing behavior in chum salmon (Oncorhynchus keta) that migrate from coastal sea to their natal river was not known well. We thus investigated temporal behavioral profiles of pre-spawning chum salmon in terms of water depth and temperature in Ishikari Bay using a micro data logger in 1997 and 1998. Fish were caught by a set net, tagged and attached with a data logger under MS222 anesthesia, and were released at the points 5 and 3 km off from the mouth of the Ishikari River in 1997 and 1998, respectively. A temporal profile of water depth and ambient...
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Changes in the Levels of Gonadotropin Subunit mRNAs in the Pituitary of Pre-Spawning Chum Salmon - Kitahashi, Takashi; Ando, Hironori; Ban, Masatoshi; Ueda, Hiroshi; Urano, Akihisa
We only have little information on expression of gonadotropin (GTH) subunit genes during spawning migration in salmonids. Changes in the levels of mRNAs for GTH subunits (GTH α2, Iβ and IIβ) were therefore analyzed in the pituitaries of chum salmon (Oncorhynchus keta) during the final stages of spawning migration to the Ishikari river. The fish were caught at Atsuta, a fisherman's village facing the Ishikari bay, and at Chitose, a tributary of the Ishikari river, in 1993 and 1994. The former is referred to as seawater (SW) fish, and the latter as freshwater (FW) fish. The levels of GTH subunit...
10.
GnRH Analog Stimulates Gonadotropin II Gene Expression in Maturing Sockeye Salmon - Kitahashi, Takashi; Alok, Deoraj; Ando, Hironori; Kaeriyama, Masahide; Zohar, Yonathan; Ueda, Hiroshi; Urano, Akihisa
Our previous study suggested that, in the pituitaries of pre-spawning chum salmon, salmon gonadotropin-releasing hormone (sGnRH) stimulates expression of genes for gonadotropin (GTH) IIβ but not for Iβ, since the levels of mRNAs encoding sGnRH and GTH II but not I were increased during the final stages of spawning migration. In the present study, a capsule of GnRH analog (GnRHa) was implanted into the dorsal muscle of maturing sockeye salmon to clarify function of GnRH on expression of GTH subunit genes in pre-spawning homing salmonids. The amounts of GTH subunit mRNAs in the individual pituitaries were analyzed by a quantitative...
11.
Gonadotropin-Releasing Hormone Analog and Sex Steroids Shorten Homing Duration of Sockeye Salmon in Lake Shikotsu - Kitahashi, Takashi; Sato, Ayako; Alok, Deoraj; Kaeriyama, Masahide; Zohar, Yonathan; Yamauchi, Kohei; Urano, Akihisa; Ueda, Hiroshi
Gonadotropin-releasing hormone analog (GnRHa), testosterone (T) or 17α, 20β-dihydroxy-4pregnen-3-one (DHP) was implanted in lacustrine sockeye salmon (Oncorhynchus nerka) to examine their effects on homing behavior prior to spawning. Maturing adult fish in Lake Shikotsu were captured by a set net adjacent to their natal hatchery in September and October, 1997. They were tagged, implanted with hormones and released at the center of lake. More than 70% of released fish returned to the hatchery. In September, GnRHa-implanted fish returned significantly earlier than the controls regardless of sexes. DHP also shortened homing duration in the females but not in the males. T...
12.
Seasonal Variation in the Expression of Five Subtypes of Gonadotropin-releasing Hormone Receptor Genes in the Brain of Masu Salmon from Immaturity to Spawning - Jodo, Aya; Kitahashi, Takashi; Taniyama, Shinya; Bhandari, Ramji Kumar; Ueda, Hiroshi; Urano, Akihisa; Ando, Hironori
Seasonal variation in the expression of five subtypes of gonadotropin-releasing hormone receptor (GnRH-R) genes, designated as msGnRH-R1, -R2, -R3, -R4, and -R5, was examined in the brain of masu salmon (Oncorhynchus masou). In addition, responses of these genes to GnRH were examined in a GnRH analog (GnRHa) implantation experiment. Brain samples were collected one week after the implantation every month from immaturity through spawning. The absolute amount of GnRH-R mRNA in single forebrains was determined by real-time PCR assays. Among the five genes, R4 and R5 were dominantly expressed in both sexes. R1, R4, and R5 mRNAs showed similar changes...
13.
Identification and Immunological Properties of an Olfactory System-Specific Protein in Kokanee Salmon (Oncorhynchus nerka) - Shimizu, Munetaka; Kudo, Hideaki; Ueda, Hiroshi; Hara, Akihiko; Shimazaki, Kenji; Yamauchi, Kohei
An olfactory system-specific protein of 24 kDa (N24) was identified in kokanee salmon (Oncorhynchus nerka) by the comparison of proteins restricted to the olfactory system (olfactory epithelium, olfactory nerve and olfactory bulb) with those found in other parts of the brain (telencephalon, optic tectum, cerebellum, hypothalamus) and hypophysis. A polyclonal antibody to N24 was raised in a rabbit, and the specificity of the antiserum was examined by Western blotting analysis; the antiserum recognized only one 24 kDa band in the olfactory system but not in other parts of the brain in kokanee salmon, sockeye salmon (O. nerka), masu salmon (O....
14.
Immunological Similarity Between an Olfactory System-Specific Protein and a Testicular Germ Cell Protein in Kokanee Salmon (Oncorhynchus Nerka) - Ueda, Hiroshi; Kudo, Hideaki; Shimizu, Munetaka; Mochida, Kazuhiko; Adachi, Shinji; Yamauchi, Kohei
An olfactory system-specific protein (N24; molecular weight 24 kDa) was examined for immunological similarity to proteins from various organs (heart, intestine, kidney, muscle, ovary and testis) of mature kokanee salmon (Oncorhynchus nerka) by means of Western blotting analysis using a polyclonal antibody to N24. The antibody recognized one 24 kDa protein in the testis but none in the other organs examined. Immunoelectron microscopic analysis revealed that immunoreactive gold particles were mainly concentrated on the nuclei of spermatids and spermatozoa, while no specific gold particles were observed on the nuclei and the cytoplasm of spermatogonia, spermatocytes, Sertoli, Leydig and peritubular cells...
15.
Two Types of cDNAs Encoding Proopiomelanocortin of Sockeye Salmon, Oncorhynchus nerka - Okuta, Akiko; Ando, Hironori; Ueda, Hiroshi; Urano, Akihisa
To investigate regulatory mechanisms of proopiomelanocortin (POMC) gene expression in sockeye salmon, we have isolated and characterized cDNAs encoding two types of sockeye salmon POMC, which are referred to as ssPOMC-A and -B. Two types of PCR products were amplified from total RNA of sockeye salmon pituitaries by use of rainbow trout sequences. Full length cDNA clones encoding ssPOMC-A and ssPOMC-B were obtained from a pituitary cDNA library of sockeye salmon using the PCR products as probes. The ssPOMC-A and -B cDNAs have a length of 1072 and 1709 bps, respectively. Northern blot analysis showed that both ssPOMC-A and -B...
16.
Sexually Different Expression of Neurohypophysial Hormone Genes in the Preoptic Nucleus of Pre-Spawning Chum Salmon - Ota, Yuki; Ando, Hironori; Ban, Masatoshi; Ueda, Hiroshi; Urano, Akihisa
Vasotocin (VT) and isotocin (IT) are teleost neurohypophysial hormones produced by neurosecretory neurons in the magnocellular part of preoptic nucleus (PM) of the hypothalamus. Several previous studies indicated that neurohypophysial hormones are involved in teleost reproductive behavior. The changes in the expression of VT and IT genes were thus studied by an in situ hybridization technique and an immunohistochemical avidin-biotin-complex method in pre-spawning chum salmon (Oncorhynchus keta). Male and female fish were caught at Atsuta, the mouth of the Ishikari Bay, and at Chitose, upstream to the Ishikari River in October, 1994. The former and the latter are referred to...
17.
Immunocytochemical Investigation of a Salmonid Olfactory System-Specific Protein in the Kokanee Salmon (Oncorhynchus nerka) - Kudo, Hideaki; Ueda, Hiroshi; Yamauchi, Kohei
Immunocytochemical and immunoelectron microscopic localizations of a salmonid olfactory system-specific protein (N24) were investigated in the olfactory system (the olfactory epithelium, the olfactory nerve and the olfactory bulb) of kokanee salmon (Oncorhynchus nerka) by using a specific antiserum to N24. N24 immunoreactivities were observed in the cytoplasm of ciliated and microvillous olfactory receptor cells but were not observed in the supporting and the basal cells in the olfactory epithelium. Gold particles showing immunoreactivities for N24 were scattered in the cytoplasm of the dendrites of olfactory receptor cells. Some particles were concentrated on vesicular structures, but none were observed in the...
18.
Sexual Differences in Homing Profiles and Shortening of Homing Duration by Gonadotropin-Releasing Hormone Analog Implantation in Lacustrine Sockeye Salmon (Oncorhynchus nerka) in Lake Shikotsu - Sato, Ayako; Ueda, Hiroshi; Fukaya, Masahiro; Kaeriyama, Masahide; Zohar, Yonathan; Urano, Akihisa; Yamauchi, Kohei
Adult sockeye salmon (Oncorhynchus nerka) in Lake Shikotsu were captured in September, October and November adjacent to their natal hatchery prior to spawning. They were sampled for hormones, tagged and released in the center of lake. Fish were again sampled at recapture to characterize changes in steroid hormone levels in individual migrants as well as homing percentage and duration in each month. All males returned faster than females early in the breeding season, although a half of the tagged males did not return to the natal site late in the season (November). A high percentage of females always returned, and...
19.
Effects of acorn masting on population dynamics of three forest-dwelling rodent species in Hokkaido, Japan - Saitoh, Takashi; Osawa, Jun; Takanishi, Toshikazu; Hayakashi, Shintaro; Ohmori, Masaaki; Morita, Toshio; Uemura, Shigeru; Vik, Jon Olav; Stenseth, Nils Chr.; Maekawa, Koji
The effects of acorn (Quercus crispula) abundance on the population dynamics of three rodent species (Apodemus speciosus, A. argenteus, and Clethrionomys rufocanus) were analyzed using time series data (1992–2006). The data were obtained in a forest in northern Hokkaido, Japan, by live trapping rodents and directly counting acorns on the ground. Apodemus speciosus generally increased in abundance following acorn masting. However, the clear effect of acorn abundance was not detected for the other two rodent species. Acorns of Q. crispula contain tannins, which potentially have detrimental effects on herbivores. Apodemus speciosus may reduce the damage caused by acorn tannins with...
20.
Effects of acorn abundance on density dependence in a Japanese wood mouse (Apodemus speciosus) population - Saitoh, Takashi; Vik, Jon Olav; Stenseth, Nils Chr.; Takanishi, Toshikazu; Hayakashi, Shintaro; Ishida, Nobuo; Ohmori, Masaaki; Morita, Toshio; Uemura, Shigeru; Kadomatsu, Masahiko; Osawa, Jun; Maekawa, Koji
We analysed the effects of Quercus crispula acorn abundance on the density dependence of the large Japanese wood mouse Apodemus speciosus using time series data (1992-2007). The data were obtained in a forest in northern Hokkaido, Japan, by live-trapping rodents and directly counting acorns on the ground. Acorn abundance in one year clearly influenced the abundance of wood mice in the following year in all models examined based on the Gompertz and Ricker model; in addition, the abundance of wood mice had effects on the population. Acorn abundance influenced the strength of density dependence (intraspecific competition) of the wood mouse...
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