中草药添加剂饲喂猪肉中CPK,GPI活性和肉质关系的研究   总被引：9，自引：0，他引：9  

韩剑众  董文明  葛长荣  高士争  黄启超 《云南农业大学学报(自然科学版)》2002,17(1):91-93

 对添加中草药和常规抗生素试验猪的背最长肌进行相关酶测定,发现磷酸肌酸激酶（CPK）,磷酸葡萄糖异构酶（GPI）的活性,试验组明显高于对照组,分别提高了30.54%和20.04%（P＜0.05）.屠宰及肉质试验表明,试验组的瘦肉率及眼肌面积分别比对照组提高5.79%和8.48%（P＜0.05）,而脂肪率、膘厚、失水率和贮存损失则分别下降31.40%,28.21%,50.03%和20.35%（P＜0.05）.  相似文献   

Oxidative damage linked to neurodegeneration by selective alpha-synuclein nitration in synucleinopathy lesions   总被引：2，自引：0，他引：2  

Giasson BI  Duda JE  Murray IV  Chen Q  Souza JM  Hurtig HI  Ischiropoulos H  Trojanowski JQ  Lee VM 《Science (New York, N.Y.)》2000,290(5493):985-989

Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of neurodegenerative synucleinopathies, and oxidative stress has been implicated in the pathogenesis of some of these disorders. Using antibodies to specific nitrated tyrosine residues in alpha-synuclein, we demonstrate extensive and widespread accumulations of nitrated alpha-synuclein in the signature inclusions of Parkinson's disease, dementia with Lewy bodies, the Lewy body variant of Alzheimer's disease, and multiple system atrophy brains. We also show that nitrated alpha-synuclein is present in the major filamentous building blocks of these inclusions, as well as in the insoluble fractions of affected brain regions of synucleinopathies. The selective and specific nitration of alpha-synuclein in these disorders provides evidence to directly link oxidative and nitrative damage to the onset and progression of neurodegenerative synucleinopathies.  相似文献   

Midbody targeting of the ESCRT machinery by a noncanonical coiled coil in CEP55   总被引：1，自引：0，他引：1  

Lee HH  Elia N  Ghirlando R  Lippincott-Schwartz J  Hurley JH 《Science (New York, N.Y.)》2008,322(5901):576-580

The ESCRT (endosomal sorting complex required for transport) machinery is required for the scission of membrane necks in processes including the budding of HIV-1 and cytokinesis. An essential step in cytokinesis is recruitment of the ESCRT-I complex and the ESCRT-associated protein ALIX to the midbody (the structure that tethers two daughter cells) by the protein CEP55. Biochemical experiments show that peptides from ALIX and the ESCRT-I subunit TSG101 compete for binding to the ESCRT and ALIX-binding region (EABR) of CEP55. We solved the crystal structure of EABR bound to an ALIX peptide at a resolution of 2.0 angstroms. The structure shows that EABR forms an aberrant dimeric parallel coiled coil. Bulky and charged residues at the interface of the two central heptad repeats create asymmetry and a single binding site for an ALIX or TSG101 peptide. Both ALIX and ESCRT-I are required for cytokinesis, which suggests that multiple CEP55 dimers are required for function.  相似文献   

Chemically derived, ultrasmooth graphene nanoribbon semiconductors     

Li X  Wang X  Zhang L  Lee S  Dai H 《Science (New York, N.Y.)》2008,319(5867):1229-1232

We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase-derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well-defined zigzag or armchair-edge structures. Electrical transport experiments showed that, unlike single-walled carbon nanotubes, all of the sub-10-nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on-off ratios of about 10(7) at room temperature.  相似文献   

Role of T-bet in commitment of TH1 cells before IL-12-dependent selection     

Mullen AC  High FA  Hutchins AS  Lee HW  Villarino AV  Livingston DM  Kung AL  Cereb N  Yao TP  Yang SY  Reiner SL 《Science (New York, N.Y.)》2001,292(5523):1907-1910

How cytokines control differentiation of helper T (TH) cells is controversial. We show that T-bet, without apparent assistance from interleukin 12 (IL-12)/STAT4, specifies TH1 effector fate by targeting chromatin remodeling to individual interferon-gamma (IFN-gamma) alleles and by inducing IL-12 receptor beta2 expression. Subsequently, it appears that IL-12/STAT4 serves two essential functions in the development of TH1 cells: as growth signal, inducing survival and cell division; and as trans-activator, prolonging IFN-gamma synthesis through a genetic interaction with the coactivator, CREB-binding protein. These results suggest that a cytokine does not simply induce TH fate choice but instead may act as an essential secondary stimulus that mediates selective survival of a lineage.  相似文献   

Alignment of liquid crystals with patterned isotropic surfaces     

Lee BW  Clark NA 《Science (New York, N.Y.)》2001,291(5513):2576-2580

The molecules of a nematic liquid crystal exposed to an isotropic surface adopt a mean tilt relative to the normal but have no in-plane alignment-that is, they are free to have any azimuthal orientation in the surface plane. Pursuing the theoretical suggestion by Meyer that, in spite of this azimuthal degeneracy, spatially inhomogeneous isotropic surfaces combine with liquid crystal elastic anisotropy to produce alignment, we show that a boundary line between two isotropic regions that differ in mean tilt does indeed align the liquid crystal. The boundaries on a patterned surface of distinct isotropic regions thus act as a system of lines that the molecular orientation locally follows. This enables the development of liquid crystal alignment surfaces based on printing or lithographic patterning.  相似文献   

Archeology of ancient china     

Chang KC 《Science (New York, N.Y.)》1968,162(3853):519-526

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A nucleation site and mechanism leading to epitaxial growth of diamond films     

Lee ST  Peng HY  Zhou XT  Wang N  Lee CS  Bello I  Lifshitz Y 《Science (New York, N.Y.)》2000,287(5450):104-106

A diamond nucleation site responsible for epitaxial growth of diamond on silicon by chemical vapor deposition (CVD) is identified in high-resolution transmission electron microscopic images. Other sites in the same sample leading to polycrystalline growth, but deleterious to epitaxial CVD growth, are also described. A mechanism for the heteroepitaxial growth of diamond is suggested, in which etching of the nondiamond carbon binder exposes and removes nonadherent nanodiamond nuclei, leaving intact only those directly nucleated on the silicon substrate. This work enhances our understanding of diamond nucleation and heteroepitaxial growth and its potential applications.  相似文献   

Wax esters in marine copepods     

Lee RF  Nevenzel JC  Paffenhöfer GA 《Science (New York, N.Y.)》1970,167(3924):1510-1511

Two pelagic copepods, Calanus helgolandicus and Gaussia princeps, contained wax esters with 28 to 44 carbon atoms as major lipid constituents. In laboratory cultures of the former species, changes in nutrition (amount or species of diatoms fed) affected both the amount of total lipid and the composition of the wax esters. Thus, the wax esters serve as a reserve energy store in this organism.  相似文献   

THE MAGNETIC POLES OF THE EARTH AND THE BIRTH OF THE MOON     

Lee OJ 《Science (New York, N.Y.)》1930,72(1856):89-90

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