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排序方式: 共有173条查询结果,搜索用时 15 毫秒
111.
Junko Nagakura Akio Akama Takeo Mizoguchi Hiroaki Okabe Hidetoshi Shigenaga Takashi Yamanaka 《Journal of Forest Research》2006,11(5):299-304
To investigate the potential effects of nitrogen (N) deposition on Japanese forests, a chronic N-addition experiment that
included three treatments (HNO3, NH4NO3, and control) was carried out in a 20-year-old Japanese cedar (Cryptomeria japonica D. Don) stand in eastern Japan over 7 years. The amount of N applied was 168 kg N ha−1 year−1 on the HNO3 plots and 336 kg N ha−1 year−1 on the NH4NO3 plots. Tree growth, current needle N concentration, and soil solution chemistry were measured. Nitrogen application decreased
the pH and increased NO3
−, Ca2+, Mg2+, and Al concentrations in the soil solution. The needle N concentration increased in both of the N plots during the first
3 years. Nevertheless, the annual increments in height and in the diameter at breast height of the Japanese cedars were not
affected by N application, and no visible signs of stress were detected in the crowns. Our results suggest that young Japanese
cedar trees are not deleteriously affected by an excess N load. 相似文献
112.
The increased plasma glucocorticoid concentration in stressful conditions stimulates muscle protein degradation, and results in growth retardation in animals. However, the mechanism is still to be clarified. The present study was undertaken to examine the participation of Ca2+ in the glucocorticoid action, using nifedipine (NIF), a Ca2+ channel antagonist. The effects of NIF on growth, differentiation, and protein degradation were examined in glucocorticoid-treated primary cultured chick muscle cells. Muscle cell growth and cell differentiation were assessed by protein content and creatine kinase (CK) activity, respectively, and the rate of myofiblillar protein degradation was estimated by the release of N τ -methylhistidine (MeHis). Creatine kinase activity was increased by corticosterone (CTC) and this effect was minimized by NIF. Protein content was decreased by CTC and normalized by NIF. N τ -methylhistidine release was significantly increased by CTC and tended to be minimized by NIF. The present results indicate that CTC increases skeletal muscle proteolysis followed by muscle growth retardation partially because of enhanced Ca2+ influx through the NIF-sensitive Ca2+ channel. Enhanced muscle differentiation by CTC is mediated also by the NIF-sensitive Ca2+ channel. 相似文献
113.
Moriyama A Fujishima J Furukawa T Yoshikawa T Kodama R Sasaki Y Nagaoka T Kamimura Y Maeda H Hirai T Yamaguchi R 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(11):1459-1464
To clarify the morphological characteristics of the cynomolgus monkey immune system, we analyzed quantitative data on their lymphoid organs. Spleens, major lymph nodes and Peyer's patches were sampled from cynomolgus monkeys, and the lymphoid follicle and germinal center areas and percentages of CD3- and CD20-positive areas were calculated. All the organs analyzed showed large interindividual variations in the sizes of lymphoid follicles and germinal centers. Lymphoid follicle in the spleen, submandibular lymph nodes and Peyer's patches showed no marked difference in size. Germinal center size in the mesenteric lymph nodes and Peyer's patches were significantly smaller than those in the spleen. Areas containing T cells were largest in the lymph nodes, while those containing B cells were largest in the spleen and Peyer's patches. The mean size of the splenic lymphoid follicle in cynomolgus monkeys is larger than that in rats and similar to that in humans. Based on the large individual variation and the characteristics of lymphoid organs, it is important to use cynomolgus monkeys in standard toxicity studies. Taking advantage of the characteristics of each species enables reliable evaluation of the immunologic system in standard toxicity studies. 相似文献
114.
Nakai M Kashiwazaki N Ito J Maedomari N Ozawa M Shino M Noguchi J Kaneko H Kikuchi K 《The Journal of reproduction and development》2011,57(2):183-187
In intracytoplasmic sperm injection (ICSI) technique, a sperm was injected into ooplasm directly using a glass pipette. The fertilization physiology in ICSI is considered quite different from that of the natural fertilization. The different mechanisms for fertilization may be the causes of various results in ICSI. In this paper, we focus on the state of sperm membranes, nuclear or DNA integrity during ICSI procedure and discuss the influence of these factors on fertilization and embryonic development. We also introduce some examples in application of ICSI for new technologies in pigs. 相似文献
115.
Yoshii K Mottate K Omori-Urabe Y Chiba Y Seto T Sanada T Maeda J Obara M Ando S Ito N Sugiyama M Sato H Fukushima H Kariwa H Takashima I 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(3):409-412
Tick-borne encephalitis virus (TBEV) is a zoonotic agent causing severe encephalitis in humans. Rodent species that are potential hosts for TBEV are widely distributed in various regions in Japan. In this study, we carried out large-scale epizootiological surveys in rodents from various areas of Japan. A total of 931 rodent and insectivore sera were collected from field surveys. Rodents seropositive for TBEV were found in Shimane Prefecture in Honshu and in several areas of Hokkaido Prefecture. These results emphasize the need for further epizootiological and epidemiological research of TBEV and preventive measures for emerging tick-borne encephalitis in Japan. 相似文献
116.
Wada T Sugatani J Terada E Ohguchi M Miwa M 《Journal of agricultural and food chemistry》2005,53(4):1246-1253
We first developed the method to produce inulin from sucrose using an enzyme from Bacillus sp. 217C-1. Synthesized inulin consists of a linear polymer having beta(2-1) linkages of d-fructose with one terminal glucose. The synthesized inulin has similar properties (pH and thermal stability, Maillard reaction, and in vitro fermentation) to plant-derived inulin. The marked difference is the polydispersity of the inulin chain length. Synthesized inulin with a narrow degree range of fructose polymerization shows better solubility in water than plant-derived inulin. Synthesized inulin (5%, w/w) treatment for 12 weeks reduced the elevation in body weight and serum and liver lipids in rats fed high fat- and high sucrose-supplemented diets, and blood glucose in rats fed a standard diet. Synthesized inulin (15%, w/w) significantly suppressed the elevation in blood glucose of human healthy subjects after dextrin loading. These results suggest that daily intake of synthesized inulin modulates carbohydrate and lipid metabolism. 相似文献
117.
Fuminori Tanihara Michiko Nakai Nguyen Thi Men Noriko Kato Hiroyuki Kaneko Junko Noguchi Takeshige Otoi Kazuhiro Kikuchi 《Animal Science Journal》2014,85(4):395-404
The zona pellucida (ZP) is considered to play important roles in the prevention of polyspermy in mammalian oocytes. However, in pigs we have shown that the presence of the ZP accelerates sperm penetration into the ooplasm during in vitro fertilization (IVF). In the present study, we investigated the effects of the ZP on sperm binding, acrosomal status, and functional exposure of IZUMO, a critical factor involved in sperm‐egg fusion, during IVF in pigs. We evaluated the numbers and acrosomal statuses of sperm binding to the ZP and oolemma, and being present in the ZP and perivitelline space (PVS) using ZP‐intact and ZP‐free oocytes. More sperm bound to the ZP than to the oolemma. The average number of sperm present in the PVS was 0.44?0.51 per oocyte, and all sperm had lost their acrosomes. The proportion of sperm that were immunopositive for anti‐IZUMO antibody was significantly higher after they were passing or had passed through the ZP. Furthermore, addition of anti‐IZUMO antibody to the fertilization medium significantly inhibited the penetration of sperm into ZP‐free oocytes. These results suggest that, in pigs, the ZP induces the acrosome reaction, which is associated with the functional exposure of IZUMO, resulting in completion of fertilization. 相似文献
118.
Nahoko IEDA Yoshihisa UENOYAMA Yoko TAJIMA Tomoko NAKATA Masatoshi KANO Yousuke NANIWA Youki WATANABE Shiori MINABE Junko TOMIKAWA Naoko INOUE Fuko MATSUDA Satoshi OHKURA Kei-ichiro MAEDA Hiroko TSUKAMURA 《The Journal of reproduction and development》2014,60(4):312-316
Puberty is associated with an increase in gonadotropin secretion as a result of an increase in gonadotropin-releasing hormone
(GnRH) secretion. Kisspeptin is considered to play a key role in puberty onset in many mammalian species, including rodents,
ruminants and primates. The present study aimed to determine if changes in hypothalamic expression of the KISS1
gene, encoding kisspeptin, are associated with the onset of puberty in pigs. The animals (n=4 in each group) were perfused with 4%
paraformaldehyde at 0, 1, 2, 3 and 4 months old, as prepubertal stages, and at 5 months old, as the peripubertal stage, following
each blood sampling. KISS1 gene expressions in coronal sections of brains were visualized by in
situ hybridization. Plasma luteinizing hormone (LH) was measured by radioimmunoassay. KISS1 mRNA
signals were observed in the arcuate nucleus (ARC) at all ages examined without any significant difference in the number of
KISS1-expressing cells, indicating that the KISS1 gene is constantly expressed in the ARC
throughout pubertal development in pigs. The plasma LH concentration was the highest in 0-month-old piglets and significantly
decreased in the 1- and 2 month-old groups (P<0.05), suggesting a developing negative feedback mechanism affecting gonadotropin
release during the prepubertal period. Considering the potent stimulating effect of kisspeptin on gonadotropin release in
prepubertal pigs, kisspeptin secretion rather than kisspeptin synthesis may be responsible for the onset of puberty in pigs. 相似文献
119.
Koji MISUMI Yuri HIRAYAMA Misae SUZUKI Michiko NAKAI Hiroyuki KANEKO Junko NOGUCHI Kazuhiro KIKUCHI 《The Journal of reproduction and development》2014,60(3):246-249
The present study was conducted to examine the feasibility of in vitro embryo production and transfer
technologies for producing Middle White piglets. After collection from three retired Middle White sows, a total of 222
oocytes were matured, fertilized and cultured in vitro, and a total of 50 embryos from the 4-cell to
blastocyst stage were produced by the 4th or 5th day. These embryos were transferred individually into three recipients along
with 5 in vivo-derived Duroc blastocysts. All of the recipients became pregnant, and they farrowed a total
of 9 Middle White and 9 Duroc piglets. These results suggest that in vitro embryo production using ovaries
from retired sows is useful for reproduction of pigs of pure breeds including the Middle White for breeding activities and
conservation/utilization of genetic resources. 相似文献
120.
Comparison of Ethylene Glycol and Propylene Glycol for the Vitrification of
Immature Porcine Oocytes
Tamás SOMFAI Michiko NAKAI Fuminori TANIHARA Junko NOGUCHI Hiroyuki KANEKO Naomi KASHIWAZAKI István EGERSZEGI Takashi NAGAI Kazuhiro KIKUCHI 《The Journal of reproduction and development》2013,59(4):378-384
Our aim was to optimize a cryoprotectant treatment for vitrification of immature porcine
cumulus-oocyte complexes (COCs). Immature COCs were vitrified either in 35% ethylene
glycol (EG), 35% propylene glycol (PG) or a combination of 17.5% EG and 17.5% PG. After
warming, the COCs were in vitro matured (IVM), and surviving oocytes were
in vitro fertilized (IVF) and cultured. The mean survival rate of
vitrified oocytes in 35% PG (73.9%) was higher (P<0.05) than that in 35% EG (27.8%).
Oocyte maturation rates did not differ among vitrified and non-vitrified control groups.
Blastocyst formation in the vitrified EG group (10.8%) was higher (P<0.05) than that in
the vitrified PG group (2.0%) but was lower than that in the control group (25.0%).
Treatment of oocytes with 35% of each cryoprotectant without vitrification revealed a
higher toxicity of PG on subsequent blastocyst development compared with EG. The
combination of EG and PG resulted in 42.6% survival after vitrification. The maturation
and fertilization rates of the surviving oocytes were similar in the vitrified, control
and toxicity control (TC; treated with EG+PG combination without cooling) groups.
Blastocyst development in the vitrified group was lower (P<0.05) than that in the
control and TC groups, which in turn had similar development rates (10.7%, 18.1% and
23.3%, respectively). In conclusion, 35% PG enabled a higher oocyte survival rate after
vitrification compared with 35% EG. However, PG was greatly toxic to oocytes. The
combination of 17.5% EG and 17.5% PG yielded reasonable survival rates without toxic
effects on embryo development. 相似文献