Inhibition of T cell receptor expression and function in immature CD4+CD8+ cells by CD4   总被引：14，自引：0，他引：14  

T Nakayama  C H June  T I Munitz  M Sheard  S A McCarthy  S O Sharrow  L E Samelson  A Singer 《Science (New York, N.Y.)》1990,249(4976):1558-1561

Most immature CD4+CD8+ thymocytes express only a small number of T cell receptor (TCR) molecules on their surface, and the TCR molecules they do express are only marginally capable of transducing intracellular signals. TCR expression and function was not intrinsically low in immature CD4+CD8+ thymocytes, but was found to be actively inhibited by CD4-mediated signals. Indeed, release of CD4+CD8+ thymocytes from CD4-mediated signals resulted in significant increases in both TCR expression and signaling function. These results suggest that, in CD4+CD8+ cells developing in the thymus, increased TCR expression and function requires release from CD4-mediated inhibition.  相似文献   

Expression and function of the segmentation gene fushi tarazu during Drosophila neurogenesis   总被引：33，自引：0，他引：33  

C Q Doe  Y Hiromi  W J Gehring  C S Goodman 《Science (New York, N.Y.)》1988,239(4836):170-175

Segmentation genes control cell identities during early pattern formation in Drosophila. One of these genes, fushi tarazu (ftz), is now shown also to control cell fate during neurogenesis. Early in development, ftz is expressed in a striped pattern at the blastoderm stage. Later, it is transiently expressed in a specific subset of neuronal precursor cells, neurons (such as aCC, pCC, RP1, and RP2), and glia in the developing central nervous system (CNS). The function of ftz in the CNS was determined by creating ftz mutant embryos that express ftz in the blastoderm stripes but not in the CNS. In the absence of ftz CNS expression, some neurons appear normal (for example, the aCC, pCC, and RP1), whereas the RP2 neuron extends its growth cone along an abnormal pathway, mimicking its sibling (RP1), suggesting a transformation in neuronal identity.  相似文献   

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

  相似文献   

Japanese universities. Junior faculty hope name change will lead to greater independence     

Yokoyama H 《Science (New York, N.Y.)》2004,306(5704):2025

  相似文献   

Effects of growth and dietary crude protein level until first insemination on milk production during first lactation in Holstein heifers     

Takashige ISHII  Kenji KAWASHIMA  Haruo ORIBE  Hiromi UEDA  Toshiya HASUNUMA  Kiyoshi AKIYAMA  Hirofumi NAKAYAMA  Mitsunori KURIHARA  Fuminori TERADA  Shiro KUSHIBIKI 《Animal Science Journal》2011,82(6):741-746

To decrease the age at first calving in Holsteins, the effects of average daily body weight gain (ADG) and crude protein (CP) level until first insemination on growth performance and milk production were examined. The MM group had a target ADG of 0.75 kg and received a diet with a CP level of 14%. The HM and HH groups had a target ADG of 1 kg; both these groups received a diet with CP levels 14% and 16%, respectively. The ADG in the HM and HH groups was 1.1 kg, whereas in the MM group it was 0.97 kg (P < 0.01). The HM and HH groups showed no differences in withers height at body weight 350 kg. The ages at first calving in MM, HM and HH groups were 23.1, 21.0 and 21.8 months, respectively. The HM and HH groups had lower milk yield at day 305 than the MM group (P < 0.01). These results suggest that growth performance until first insemination should be maintained at an ADG of 0.97 kg or less with a CP level of approximately 14%, to shorten time until first insemination and prevent the decrease of milk yield.  相似文献   

Characterization of corrinoid compounds from a Japanese black tea (Batabata-cha) fermented by bacteria     

Kittaka-Katsura H  Ebara S  Watanabe F  Nakano Y 《Journal of agricultural and food chemistry》2004,52(4):909-911

A Japanese fermented black tea (Batabata-cha) contained a considerable amount of vitamin B(12) (456 +/- 39 ng per 100 g dry tea leaves and 2.0 +/- 0.3 ng per 100 mL of tea drink). A corrinoid compound was partially purified and characterized from the tea leaves. The patterns of the purified compound by the silica gel 60 thin-layer chromatography and C18 reversed phased high-performance liquid chromatography were identical to those of authentic vitamin B(12). When 20 week old vitamin B(12) deficient rats, which excreted substantial amounts (about 250 mg/day) of methylmalonic acid in urine as an index of vitamin B(12) deficiency, were fed the tea drink (50 mL/day, 1 ng of vitamin B(12)) for 6 weeks, urinary methylmalonic acid excretion (169 +/- 29 mg/day) of the tea drink-supplemented 26 week old rats decreased significantly relative to that (250 +/- 32 mg/day) of the deficient rats. The results indicate that the vitamin B(12) found in the fermented black tea is bioavailable in mammals.  相似文献   

Relationship between antibacterial activity of (+)-catechin derivatives and their interaction with a model membrane     

Kajiya K  Hojo H  Suzuki M  Nanjo F  Kumazawa S  Nakayama T 《Journal of agricultural and food chemistry》2004,52(6):1514-1519

(+)-Catechin derivatives with different alkyl chain lengths were synthesized from (+)-catechin and various straight chain alkylaldehydes in the presence of methyl mercaptan, and their antibacterial activities against Gram-positive bacteria were evaluated. The antibacterial activity increased markedly with elongation of the alkyl chain lengths of the derivatives and reached a maximum at a chain of four to seven carbons. Subsequently, interaction of the (+)-catechin derivatives with a model membrane using liposome was investigated. The derivatives with a chain of three carbons or more were found to have very strong affinity for the membrane. The injury action of the derivatives against the membrane was examined with liposome in which calcein was enclosed as a fluorescent indicator. The leakage was observed in the derivatives with chain lengths of four carbons or more. Particularly the derivatives with chains longer than five carbons are considered to destroy the liposome membrane judging from the degree of the fluorescent leakage. These results implied that the lipophilicity and disrupting ability of the (+)-catechin derivatives to the liposome membrane participate in their antibacterial activity.  相似文献   

Liver lesions and serum antibodies in mice surviving Tyzzer's disease     

H Nakayama  S Inoue  A Nii  A Yasuda  N Okada  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1986,48(1):189-192

  相似文献   

No significant differences were observed in the amounts of DNA strand breaks produced by copper between male and female liver cells of long-evans cinnamon (LEC) strain rats.     

M Hayashi  T Kuge  D Endoh  K Nakayama  J Arikawa  A Takazawa  T Okui 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(10):1109-1113

The amounts of DNA single strand breaks that are oxidative damage produced by copper were examined by comet assay in the liver cells of an inbred strain of Long-Evans Cinnamon (LEC) rats that spontaneously develops fulminant hepatitis. At 4 weeks of age, copper contents in the liver of LEC rats were approximately 30-fold higher than those of WKAH rats that are control rats used in the present study. Copper accumulated in the liver of LEC rats in an age-dependent manner and no significant differences were observed between copper contents in the livers of males and females at each week of age from 4 to 15 weeks. No significant amounts of DNA strand breaks were found in the liver cells of both male and female WKAH rats from 4 to 15 weeks of age. DNA strand breaks were produced in the substantial population of LEC rat liver cells at 10 weeks of age and induced in an age-dependent manner from 10 to 15 weeks of age. The amounts of DNA strand breaks produced by copper accumulation in the liver cells of female LEC rats are not more abundant than those in the cells of male rats, although it has been reported that hepatitis in female rats is more serious than that in male rats.  相似文献   

Immunohistochemical analysis of constituents of senile plaques and cerebro-vascular amyloid in aged dogs.     

K Uchida  H Nakayama  S Tateyama  N Goto 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(5):1023-1029

Immunohistochemical analysis of constituents of senile plaques and cerebro-vascular amyloid in the brain of aged dogs was performed using antisera against beta protein, cystatin C, ubiquitin, tau, and neurofilament (NF). All types of senile plaques and cerebro-vascular amyloid in aged dogs were labeled by anti-beta protein serum. Cystatin C immunoreactivity was detected in neuronal cell bodies, primitive or classical plaques, and amyloid deposited around cerebral capillaries, but not in diffuse plaques and amyloid deposited in the media tunica of cerebro-meningeal arterioles. Ubiquitin-positive granules distributed widely in both gray and white matter of aged dogs, while they were very small in number in young dogs. Swollen neurites-like materials in primitive plaques or classical plaques were immunoreactive for anti-ubiquitin serum. Tau immunostaining labeled commonly axons and several neuronal or glial cells after hydrate autoclave pretreatment. Tau-positive components were observed very rarely in the corona of classical plaques. Most of swollen neurites-like structures of primitive or classical plaques were not reactive for anti-NF serum, and only a few plaques contained small numbers of NF-positive elements.  相似文献