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Calf lens fiber membranes and fractions enriched in junction-like structures have been isolated in the absence and presence of EDTA. Their biochemical features have been studied. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting experiments have provided evidence that a distinct group of EDTA-extractable proteins, being one of the main protein components of calf lens fiber membranes and very likely also of junction-like structures, is bound to these membranes via calcium ions. In addition to these proteins, four polypeptides with apparent molecular weights between 14 000 and 17 000 are characteristic for detergent-insoluble lens fiber structures prepared in calcium-rich medium. The absence of EDTA-extractable proteins in the urea-soluble calcium-containing fraction implies that they are not components of the cytoskeleton and that the calcium-dependent binding of these proteins to the membrane is urea-resistant. The use of EDTA throughout the whole membrane isolation procedure results in their complete removal from the membranes which already starts during buffer washing. This indicates that EDTA-extractable proteins exclusively consist of extrinsic membrane proteins which probably are not involved in cytoskeleton binding. 相似文献
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S.Candeloro De Sanctis L. Toniolo T. Boschi G. Deganello 《Inorganica chimica acta》1975,12(1):251-254
Reaction of [Pd(1-3-η-allyl)Cl]2 with lithium triazenide (triazenide = p-XC6H4NN-NC6H4X-p; X = Cl, H, CH3) affords dimeric complexes of the type [Pd(1-3-η-allyl)(triazenide)]2. In the solid state the triazenido ligands are bridging two palladium atoms with their terminal nitrogen atoms, as shown by a preliminary X-ray determination of the complex with X = CH3. The allyl groups are stereochemically equivalent. 1H NMR spectra demonstrate the presence of two conformers in solution. The major component has the same configuration found in the solid. The other conformer has stereochemically non equivalent allyl groups. The concentration ratio of the two conformers is independent of the temperature, suggesting the absence of intramolecular processes and of palladium- triazenido bond breaking. This point is discussed also by comparing the (1-3-η-allyl)(triazenide)palladium (II) dimers with the closely related(1-3-η-allyl)(acetate)palladium(II) complexes. 相似文献
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L. Chaerle F. De Boever M. Van Montagu & D. Van Der Straeten 《Plant, cell & environment》2001,24(1):15-25
Pending cell death was visualized by thermographic imaging in bacterio‐opsin transgenic tobacco plants. Cell death in these plants was characterized by a complex lesion phenotype. Isolated cell death lesions were preceded by a colocalized thermal effect, as previously observed at sites infected by tobacco mosaic virus (TMV) ( Chaerle et al. 1999 Nature Biotechnology 17, 813–816). However, in most cases, a coherent front of higher temperature, trailed by cell death, initiated at the leaf base and expanded over the leaf lamina. In contrast to the homogenous thermal front, cell death was first visible close to the veins, and subsequently appeared as discrete spots on the interveinal tissue, as cell death spread along the veins. Regions with visible cell death had a lower temperature because of water evaporation from damaged cells. In analogy with previous observations on the localized tobacco–TMV interaction ( Chaerle et al. 1999 ), the kinetics of thermographic and continuous gas exchange measurements indicated that stomatal closure preceded tissue collapse. Localized spontaneous cell death could also be presymptomatically visualized in the Arabidopsis lsd2 mutant. 相似文献
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A cholinergic proteolipid fraction (i.e. a hydrophobic lipoprotein) was separated from the of the cow, using affinity chromatography with the lipophilic gel Sephadex LH-20 and p-phenyltrimethylamonium as the active group. High affinity binding studies showed that only the specific fraction, desorbed after an acetylcholine (or acid) pulse, and corresponding to 0,72% of the proteolipids, is the one that binds the cholinergic ligands. The binding of (3H)atropine and (14C)d-tubocurarine demonstrated that there are 814 picomoles/g fresh tissue of muscarinic sites and only 76 picomoles/g of nicotinic sites. The specific radioactivity for (3H)atropine is 10,000 nmoles/g protein, suggesting a high degree of purification of the specific cholinergic proteolipid. 相似文献
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Siddhartha Kumar Bhaumik Manoj Kumar Singh Subir Karmakar Tripti De 《Glycoconjugate journal》2009,26(6):663-673
As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In
this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated
(in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the
attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis. 相似文献