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1.
Abstract— β- N -Acetyl D-galactosaminidase was studied in isolated neuronal and neuropil fractions from cerebral cortex and subcellular fractions derived from them. Although the enzyme activity evinced some latency properties, its subcellular distribution pattern was broader than that observed with other acid hydrolases. By contrast with nine other acid hydrolases, it was more active in neuropil than neuronal fractions (neuronal/neuropil activity ratio 0.63). This ratio was preserved in lysosomal subfractions derived from the isolated cell fractions. The data is taken as further evidence for the microheterogeneity of lysosomal particles from the brain. 相似文献
2.
Julia I. Gavrilyuk Ulrich Wuellner Syed Salahuddin Rajib K. Goswami Subhash C. Sinha Carlos F. Barbas 《Bioorganic & medicinal chemistry letters》2009,19(14):3716-3720
Irreversible chemical programming of monoclonal aldolase antibody (mAb) 38C2 has been accomplished with β-lactam equipped mono- and bifunctional targeting modules, including a cyclic-RGD peptide linked to either the peptide (d-Lys6)-LHRH or another cyclic RGD unit and a small-molecule integrin inhibitor SCS-873 conjugated to (d-Lys6)LHRH. We also prepared monofunctional targeting modules containing either cyclic RGD or (d-Lys6)-LHRH peptides. Binding of the chemically programmed antibodies to integrin receptors α(v)β(3) and α(v)β(5) and to the luteinizing hormone releasing hormone receptor were evaluated. The bifunctional and bivalent c-RGD/LHRH and SCS-783/LHRH, the monofunctional and tetravalent c-RGD/c-RGD, and the monofunctional bivalent c-RGD chemically programmed antibodies bound specifically to the isolated integrin receptor proteins as well as to integrins expressed on human melanoma M-21 cells. c-RGD/LHRH, SCS-783/LHRH, and LHRH chemically programmed antibodies bound specifically to the LHRH receptors expressed on human ovarian cancer cells. This approach provides an efficient, versatile, and economically viable route to high-valency therapeutic antibodies that target defined combinations of specific receptors. Additionally, this approach should be applicable to chemically programmed vaccines. 相似文献
3.
4.
Ichthyological Research - A new glyptosternine catfish, Creteuchiloglanis arunachalensis is described on the basis of a single specimen collected from the upper Brahmaputra River drainage,... 相似文献
5.
Jesus Torres-Bacete Prem Kumar Sinha Motoaki Sato Gaurav Patki Mou-Chieh Kao Akemi Matsuno-Yagi Takao Yagi 《The Journal of biological chemistry》2012,287(51):42763-42772
The bacterial H+-translocating NADH:quinone oxidoreductase (NDH-1) catalyzes electron transfer from NADH to quinone coupled with proton pumping across the cytoplasmic membrane. The NuoK subunit (counterpart of the mitochondrial ND4L subunit) is one of the seven hydrophobic subunits in the membrane domain and bears three transmembrane segments (TM1–3). Two glutamic residues located in the adjacent transmembrane helices of NuoK are important for the energy coupled activity of NDH-1. In particular, mutation of the highly conserved carboxyl residue (KGlu-36 in TM2) to Ala led to a complete loss of the NDH-1 activities. Mutation of the second conserved carboxyl residue (KGlu-72 in TM3) moderately reduced the activities. To clarify the contribution of NuoK to the mechanism of proton translocation, we relocated these two conserved residues. When we shifted KGlu-36 along TM2 to positions 32, 38, 39, and 40, the mutants largely retained energy transducing NDH-1 activities. According to the recent structural information, these positions are located in the vicinity of KGlu-36, present in the same helix phase, in an immediately before and after helix turn. In an earlier study, a double mutation of two arginine residues located in a short cytoplasmic loop between TM1 and TM2 (loop-1) showed a drastic effect on energy transducing activities. Therefore, the importance of this cytosolic loop of NuoK (KArg-25, KArg-26, and KAsn-27) for the energy transducing activities was extensively studied. The probable roles of subunit NuoK in the energy transducing mechanism of NDH-1 are discussed. 相似文献
6.
7.
Indirect evidence suggests that legumes can adjust rapidly theresistance of their root nodules to O2 diffusion. Here we describeexperiments using O2 specific micro-electrodes and dark fieldmicroscopy to study directly the operation of this diffusionbarrier. The O2 concentration sensed by the electrode decreasedsharply in the region of the inner cortex and was less than1.0 mmol m3 throughout the infected tissue in nodulesof both pea (Pisum sativum) and french bean (Phaseolus vulgaris).In a number of experiments the ambient O2 concentration wasincreased to 40% while the electrode tip was just inside theinner cortex. In 13 out of 21 cases the O2 concentration atthis position either remained low and unchanged or increasedirreversibly to near ambient values. In the remaining casesthe O2 concentration increased after 1 to 2.5 min and then decreasedto its former value. These results are ascribed to an increasein resistance of the barrier in response to increased O2 fluxinto the nodule. It was shown microscopically that air spacesboth at the boundary between the infected zone and the innercortex, and within the infected zone started to disappear 3min after nodules were exposed to high ambient O2 concentrationsand had disappeared completely after 8 min. These spaces werenot changed by exposure of the nodule for 10 min to either N2or air. Key words: Oxygen, root nodules, air spaces 相似文献
8.
Evolution of the 28S ribosomal RNA gene in anurans: regions of variability and their phylogenetic implications 总被引:1,自引:0,他引:1
Fifteen restriction sites were mapped to the 28S ribosomal RNA gene of
individuals representing 54 species of frogs, two species of salamanders, a
caecilian, and a lungfish. Eight of these sites were present in all species
examined, and two were found in all but one species. Alignment of these
conserved restriction sites revealed, among anuran 28S rRNA genes, five
regions of major length variation that correspond to four of 12 previously
identified divergent domains of this gene. One of the divergent domains
(DD8) consists of two regions of length variation separated by a short
segment that is conserved at least throughout tetrapods. Most of the
insertions, deletions, and restriction-site variations identified in the
28S gene will require sequence-level analysis for a detailed reconstruction
of their history. However, an insertion in DD9 that is coextensive with
frogs in the suborder Neobatrachia, a BstEII site that is limited to
representatives of two leptodactylid subfamilies, and a deletion in DD10
that is found only in three ranoid genera are probably synapomorphies.
相似文献
9.
Activation of hydrazine derivatives to free radicals in the perfused rat liver: a spin-trapping study 总被引:1,自引:0,他引:1
B K Sinha 《Biochimica et biophysica acta》1987,924(2):261-269
Spin-trapping techniques and electron spin resonance spectroscopy have been used to study bioactivations of hydrazine and its derivatives by isolated perfused rat livers. Using phenylbutylnitrone (PBN) as the stable spin trap, it was found that the liver perfusion of hydrazine, acetylhydrazine and isoniazid resulted in the formation of the same carbon-centered radical which was shown to be the acetyl radical. The identity of the acetyl radical was confirmed after organic extraction of the liver perfusates, by comparing its coupling constants with those of the in vitro metal ion- or horseradish peroxidase-catalyzed oxidation products of the hydrazines in the same solvents. The liver perfusion of iproniazid formed the isopropyl radical which was previously observed to result from peroxidase-catalyzed oxidation. 相似文献
10.
P Sinha M Seidel P G Righetti I Bause-Niedrig E K?ttgen 《Journal of biochemical and biophysical methods》1989,18(3):195-208
A new technique is described for in situ visualization of the activity of intestinal disaccharidases after isoelectric focusing in immobilized pH gradients using their physiological substrates. The reaction principle is based on the oxidation of D-glucose, liberated by the disaccharidases, into D-gluconolactone and the production of NADH by glucose dehydrogenase. At the sites of enzymatic activity, tetrazolium salts present in the reaction mixture are reduced to relatively water-insoluble formazans by NADH. The rate of formazan production is increased by the presence of phenazine methosulfate. An additional modification of the technique involves the use of polyvinyl alcohol in the substrate solution. Due to the increase in the viscosity of the substrate solution, leakage of the enzyme from the IPG gels is minimized. Incubation times can thus be prolonged without loss of resolution and band-blurring. 相似文献