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Identification of SH2-B as a key regulator of leptin sensitivity, energy balance, and body weight in mice 总被引:1,自引:0,他引:1
Leptin regulates energy balance and body weight by activating its receptor LEPRb and multiple downstream signaling pathways, including the STAT3 and the IRS2/PI 3-kinase pathways, in the hypothalamus. Leptin stimulates activation of LEPRb-associated JAK2, which initiates cell signaling. Here we identified SH2-B, a JAK2-interacting protein, as a key regulator of leptin sensitivity, energy balance, and body weight. SH2-B homozygous null mice were severely hyperphagic and obese and developed a metabolic syndrome characterized by hyperleptinemia, hyperinsulinemia, hyperlipidemia, hepatic steatosis, and hyperglycemia. The expression of hypothalamic orexigenic NPY and AgRP was increased in SH2-B(-/-) mice. Leptin-stimulated activation of hypothalamic JAK2 and phosphorylation of hypothalamic STAT3 and IRS2 were significantly impaired in SH2-B(-/-) mice. Moreover, overexpression of SH2-B counteracted PTP1B-mediated inhibition of leptin signaling in cultured cells. Our data suggest that SH2-B is an endogenous enhancer of leptin sensitivity and required for maintaining normal energy metabolism and body weight in mice. 相似文献
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A conserved RNA recognition motif (RRM) domain of Brassica napus FCA improves cotton fiber quality and yield by regulating cell size 总被引:2,自引:0,他引:2
Fan Sun Chuanliang Liu Chaojun Zhang Weiwei Qi Xueyan Zhang Zhixia Wu Depei Kong Qianhua Wang Haihong Shang Xiaoyin Qian Fuguang Li Jinshui Yang 《Molecular breeding : new strategies in plant improvement》2012,30(1):93-101
Cotton (Gossypium hirsutum L.) is an important crop that is used to produce both natural textile fiber and cottonseed oil. Cotton fiber is a unicellular trichome, whose length is critical to fiber quality and yield but difficult to modify. FCA was originally identified based on flowering time control in Arabidopsis. The function of the second RNA recognition motif (RRM) domain of Oryza sativa FCA in rice cell-size regulation has been previously reported, showing it to be highly conserved across dicotyledonous and monocotyledonous plants. The present study showed that the second RRM domain of Brassica napus FCA functioned in Gossypium hirsutum, leading to enlargement of multiple cell types, such as pollen, cotyledon petiole, and cotton fiber. In the resulting transgenic cotton, fiber length increased by ~10% and fiber yield per plant showed a dramatic increase, ranging from 35 to 66% greater than controls. Thus, this RRM domain may be a cell-size regulator and have great economic value in the cotton industry. 相似文献
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ABSTRACT: BACKGROUND: Several reports have associated Staphylococcus lugdunensis with the incidence of severe infection in humans; however, the frequency and prevalence of this microorganism and thus the propensity of its antimicrobial drug resistance is unknown in China. The objective of the current study was to determine the prevalence of Staphylococcus lugdunensis among six hundred and seventy non-replicate coagulase negative Staphylococcus (CoNS) isolates collected in a 12-month period from clinical specimens in the General Hospital of the People's Liberation Army in Beijing, China. RESULTS: Five (0.7%) of the 670 isolates of CoNS were identified as S. lugdunensis. Whereas three isolates were resistant to erythromycin, clindamycin, and penicillin and carried the ermC gene and a fourth one was resistant to cefoxitin and penicillin and carried the mecA gene, one isolate was not resistant to any of the tested antimicrobials. Pulse field gel electrophoretic analysis did not reveal widespread epidemiological diversity of the different isolates. CONCLUSION: Hence, even though S. lugdunensis may be yet unrecognized and undefined in China, it still might be the infrequent cause of infection and profound multi-drug resistance in the same population. 相似文献
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Shaofen Guo Rui Cao Aihua Lu Qing Zhou Tianhong Lu Xiaolan Ding Chaojun Li Xiaohua Huang 《Journal of biological inorganic chemistry》2008,13(4):587-597
One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III) was investigated using some biophysical and biochemical methods. Firstly, it was found that a large
amount of Tb(III) can be distributed on the cell wall, that some Tb(III) can enter into the horseradish cell, indicating that
peroxidase was mainly distributed on cell wall, and thus that Tb(III) would interact with horseradish peroxidase (HRP) in
the plant. In addition, peroxidase bioactivity was decreased in the presence of Tb(III). Secondly, a new peroxidase-containing
Tb(III) complex (Tb–HRP) was obtained from horseradish after treatment with Tb(III); the molecular mass of Tb–HRP is near
44 kDa and the pI is about 8.80. Thirdly, the electrocatalytic activity of Tb–HRP is much lower than that of HRP obtained
from horseradish without treatment with Tb(III). The decrease in the activity of Tb–HRP is due to the destruction (unfolding)
of the conformation in Tb–HRP. The planarity of the heme active center in the Tb–HRP molecule was increased and the extent
of exposure of Fe(III) in heme was decreased, leading to inhibition of the electron transfer. The microstructure change in
Tb–HRP might be the result of the inhibition effect of Tb(III) on peroxidase activity in horseradish. 相似文献
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Oxygen Evolution: FeN4 Sites Embedded into Carbon Nanofiber Integrated with Electrochemically Exfoliated Graphene for Oxygen Evolution in Acidic Medium (Adv. Energy Mater. 26/2018) 下载免费PDF全文