Oscillatory expression of the bHLH factor Hes1 regulated by a negative feedback loop   总被引：1，自引：0，他引：1  

Hirata H  Yoshiura S  Ohtsuka T  Bessho Y  Harada T  Yoshikawa K  Kageyama R 《Science (New York, N.Y.)》2002,298(5594):840-843

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Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus     

Watanabe T  Tomizawa S  Mitsuya K  Totoki Y  Yamamoto Y  Kuramochi-Miyagawa S  Iida N  Hoki Y  Murphy PJ  Toyoda A  Gotoh K  Hiura H  Arima T  Fujiyama A  Sado T  Shibata T  Nakano T  Lin H  Ichiyanagi K  Soloway PD  Sasaki H 《Science (New York, N.Y.)》2011,332(6031):848-852

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.  相似文献   

Lysozyme-glucose stearic acid monoester conjugate formed through the Maillard reaction as an antibacterial emulsifier     

Takahashi K  Lou XF  Ishii Y  Hattori M 《Journal of agricultural and food chemistry》2000,48(6):2044-2049

Lysozyme-glucose stearic acid monoester (HEL-GE) conjugate was prepared through the Maillard reaction as an antibacterial emulsifier. The molar ratio of GE to HEL was 1:1. The isoelectric point was 6-7, which is lower than that of native HEL. Spectroscopic studies indicated that the alpha-helix content was slightly lower but the conformation around Trp had not changed and that the surface of the conjugate was covered with the GE moiety. The conjugate maintained approximately 53-57% of the enzymatic activity of native HEL at 40-60 degrees C and exhibited considerable resistance to proteolysis. The denaturation temperature of the conjugate was approximately 74 degrees C, somewhat higher than that of control HEL, whereas the enthalpy was about one-third of that of control HEL. The emulsifying activity of the conjugate and the emulsion stability were much enhanced compared to those of native HEL, and the conjugate maintained approximately 70% of the bactericidal activity.  相似文献   

Physiological and Morphological Responses of Locally Grown Malaysian Rice Cultivars (Oryza Sativa L.) to Different Ozone Concentrations     

Ishii  S.  Marshall  F. M.  Bell  J. N. B. 《Water, air, and soil pollution》2004,155(1-4):205-221

Malaysian rice (Oryza sativa L.) cultivars MR84 and MR185 were grown in greenhouse chambers and exposed to four different levels of ozone from 28th August, 2001 to 22nd January, 2002. Four ozone levels were selected in close relation to the Malaysian peri-urban ambient level (approximately 30 ppb, 8 hr mean), the Malaysian guideline level (approximately 60 ppb) and possible future higher ozone levels (approximately 90 ppb). Both morphological and physiological parameters showed distinctive impacts of ozone treatments. The plants treated with the highest ozone concentration showed different morphological development, probably induced by severe foliar injury and physiological adaptation of the plants to the ozone stress. The physiological measurements revealed a high sensitivity at the early and late vegetative stages. It was concluded that MR84, which was found to be physiologically sensitive, responded to ozone relatively quickly and altered its morphology to compensate for effects on growth and yield, while MR185, found to be physiologically insensitive, responded to ozone stress slowly which resulted in more severe impacts on growth and yield parameters. Slight growth stimulation was observed at the lowest (30 ppb) ozone level for MR185, whilst negative impacts on growth occurred at both of the higher ozone levels. The study provided useful insights into the earlier findings of an open-top chamber filtration study on the same cultivars in the field at a peri-urban site in Malaysia. The present study proved that yield could be reduced substantially when other parameters associated with grain yield were affected, which was accompanied by increasing yellowing of leaves and premature senescence.  相似文献   

Testicular development and serum steroid hormone levels in captive male spotted halibut Verasper variegatus     

Yasunori  KOYA  Hiroki  WATANABE  Kiyoshi  SOYANO  Kengo  OHTA  Masato  ARITAKI  Takahiro  MATSUBARA 《Fisheries Science》2003,69(4):792-798

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Artificial infection by transplantation of juvenile Fasciola worms into the abdominal cavity of rats     

H Saeki  N Taira  Y Tomishita  T Ishii 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(1):151-156

Rats were successfully infected with Japanese Fasciola sp. by transplantation of juvenile worms (JW) or metacercariae (MC) into the abdominal cavity. Moreover, the rat was investigated on its suitability for different experiments with liver flukes. JWs or MCs transplanted intraperitoneally (IP) matured in the bile duct of rats. Moreover, more stable infections were established by inoculation of JWs than MCs. About 3 of 10-15 JWs transplanted into the abdominal cavity of a rat matured and laid eggs in the bile duct. The mean prepatent period was 63.5 days in the JW inoculated group. EPG values were kept constant at a level of 10(2)-10(3) about 100 to 230 days after the transplantation of JWs. The life span of Japanese liver flukes was estimated to be about 400 days in rats. From these results, it was concluded that the rat is suitable for various experiments with Fasciola sp.  相似文献   

Effect of the strain combination of the donor and recipient on the production efficiency of W‐bearing sperm in mixed‐sex germline chimeric chickens     

Hiroshi KAGAMI  Jun YASUDA  Takahiro TAGAMI  Mitsuru NAITO  Yuko MATSUBARA  Takashi HARUMI  Takamasa NOGUCHI  Yasuhiro YAMAMOTO  Taikai TAKAHASHI  Junichi MATSUYAMA  Hiroyuki KOMATSU  Tamao ONO 《Animal Science Journal》2002,73(6):453-456

Effect of the strain combination of the donor and recipient on production efficiency of W‐bearing sperm in mixed‐sex chimeric testes was analyzed. The combinations of the donors and recipients were White Leghorn (WL) and Rhode Island Red (RIR), and vice versa. Generated mixed‐sex chimeras that had the male phenotype at sexual maturity were classified into four groups: (1) a female WL donor and a male RIR recipient; (2) a male WL donor and a female RIR recipient; (3) a female RIR donor and a male WL recipient; (4) a male RIR donor and a female WL recipient. The mean number of W‐bearing sperm detected by in situ hybridization among 10 000 sperm observed were 147, 165, 30 and 45 in groups 1, 2, 3 and 4, respectively. The numbers in groups 1 and 2 were both significantly higher than those of groups 3 and 4 (P < 0.05). The combination of a WL donor and a RIR recipient produced W‐bearing sperm more efficiently than the reverse combination.  相似文献   

Characterization and classification of Actinobacillus (Haemophilus) pleuropneumoniae plasmids.     

H Ishii  F Hayashi  S Iyobe  H Hashimoto 《American journal of veterinary research》1991,52(11):1816-1820

Actinobacillus (Haemophilus) pleuropneumoniae plasmids were characterized and classified. They were isolated from A pleuropneumoniae strains different in serotype, year isolated, or location from which isolated. Six of 8 plasmids encoded streptomycin (Sm) and sulfonamide (Su) resistance (SmSu). One of the other plasmids, pVM105, encoded ampicillin (Ap) resistance and another, pHM0, encoded no drug resistance. All SmSu plasmids were transferred to Escherichia coli strains by transformation. Among them, pABO and pMS260 were 8.1 kb and incompatible with each other; they were stable in E coli. The other SmSu plasmids, pHM1, pVM104, pVM106, and pKD25, were 4.3 kb and did not replicate stably in E coli. The former SmSu plasmids were mobilized in E coli strains by a plasmid RP4, which belonged to incompatibility (Inc) group P, but the latter plasmids were not. Further, each 8.1-kb SmSu plasmid and each 4.3-kb plasmid had the same respective restriction pattern. These results indicated that there were at least 2 types of SmSu plasmids in A pleuropneumoniae. The 2 types were classified in 2 groups: H1(pMS260 and pABO) and H2(pHM1, pVM104, pVM106, and pKD25). The H1 and H2 plasmids belonged to different Inc groups, and H2 plasmids belonged to a different Inc group from that of pHMO and pVM105.  相似文献   

Levels of immunoglobulin and complement in serum of rats with congenital susceptibility to gingivitis     

H Isogai  E Isogai  H Wakizaka  N Ito  B Syuto  F Ishii  K Takano 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1987,49(6):949-955

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Fixation to the canine bone of artificial implant with new surface structure     

Seno T  Izumisawa Y  Nishimura I  Maehara S  Kushiro T  Umar MA  Wakaiki S  Yamashita K  Kotani T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(3):315-318

Screw and laser (SL) column by making screw threads and forming small holes using laser irradiation on the base metal and conventional beads coating (BC) columns were embedded into the shaft of canine femurs, and compared the implant fixation to the host bone. The interfacial strength in SL columns was almost equivalent as BC columns, and bone-column contact rate was higher than BC columns significantly at twelve weeks after implantation. The newly devised SL surface had almost equivalent bone fixation strength comparable to the conventional BC surface. Also, this surface should provide a useful porous surface for use in artificial joints since there is no risk of surface structure detachment.  相似文献