Hepatitis C virus core protein interacts with the cytoplasmic tail of lymphotoxin-beta receptor.

Hepatitis C virus (HCV) core protein is a multifunctional protein. We examined whether it can interact with cellular proteins, thus contributing to viral pathogenesis. Using the HCV core protein as a bait to screen a human liver cDNA library in a yeast two-hybrid screening system, we have isolated several positive clones encoding cellular proteins that interact with the HCV core protein. Interestingly, more than half of these clones encode the cytoplasmic domain of lymphotoxin-beta receptor (LT betaR), which is a member of the tumor necrosis factor receptor family. Their binding was confirmed by in vitro glutathione S-transferase fusion protein binding assay and protein-protein blotting assay to be direct and specific. The binding sites were mapped within a 58-amino-acid region of the cytoplasmic tail of LT betaR. The binding site in the HCV core protein was localized within amino acid residues 36 to 91 from the N terminus, corresponding to the hydrophilic region of the protein. In mammalian cells, the core protein was found to be associated with the membrane-bound LT betaR. Since the LT betaR is involved in germinal center formation and developmental regulation of peripheral lymphoid organs, lymph node development, and apoptotic signaling, the binding of HCV core protein to LT betaR suggests the possibility that this viral protein has an immunomodulating function and may explain the mechanism of viral persistence and pathogenesis of HCV.     

拉萨郊区藏族的指纹研究

本文报道了拉萨郊区５１７例（男２２６人,女２９１人）藏族健康人的指纹参数正常值、调查分析了指纹类型、指纹组合、指纹指数和指嵴纹计数。比较了藏族不同居群、不同民族和人种间的差异。结果表明,藏族有自己的指纹特点,又显著蒙古人种的一般特征。     

新型平均势函数在蛋白质反向折叠中的应用

利用蛋白质主链的极性分数及主链二面角为参量,构建了一种基于蛋白质结构数据库的势函数。将该势函数应用于蛋白质反向折叠研究中,发现该函数可成功地将蛋白质分子的天然构象从构建的构象库中识别出来;将一目标序列与构象库的每一可能的构象匹配,并用该势函数计算相应的能量,结果表明对绝大多数蛋白质分子来说,天然的构象的能量值总是最低。此外,该函数还将一些序列相似性较低,而结构相似性较高的蛋白质分子识别出来。我们认     

An analysis of the unconfined compression of articular cartilage

Analytical solutions have been obtained for the internal deformation and fluid-flow fields and the externally observable creep, stress relaxation, and constant strain-rate behaviors which occur during the unconfined compression of a cylindrical specimen of a fluid-filled, porous, elastic solid, such as articular cartilage, between smooth, impermeable plates. Instantaneously, the "biphasic" continuum deforms without change in volume and behaves like an incompressible elastic solid of the same shear modulus. Radial fluid flow then allows the internal fluid pressure to equilibrate with the external environment. The equilibrium response is controlled by the Young's modulus and Poisson's ratio of the solid matrix.     

Hematochemical parameters in sheep and goats of Sardinian breeds. II) Total blood cholesterol

It has been studied the total plasma cholesterol rate in lactating or dry sheep and goats of Sardinian breed. The values obtained for the four different groups of subjects have been compared with the "t of Student". While the difference between the sheep groups has seemed very accentuated, it has appeared hardly significant between the goat groups. Highly significant difference has also been found between lactating sheep and goats whereas there was no significant difference among the groups of dry subjects.     

Hydroxyl radical production in a purified NADPH--cytochrome c (P-450) reductase system.

Using the spin trap, 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) we have demonstrated that hydroxyl radicals are generated indirectly from purified preparations of rat liver microsomal NADPH-cytochrome c (P-450) reductase during NADPH oxidation. Hydroxyl radical formation is completely inhibited by p-chloromercuribenzoate, but not by metyrapone. In addition, hydroxyl radical DMPO adduct formation is blocked by added linolenic acid which, in turn, is peroxidatively degraded into malondialdehyde, suggesting that hydroxyl radicals formed from purified NADPH-cytochrome c (P-450) reductase are capable of initiating lipid peroxidation. A mechanism for the indirect production of hydroxyl radicals from NADPH-cytochrome P-450 reductase is discussed.     

Synthesis of the spin-labeled derivative of an ether-linked phospholipid possessing high antineoplastic activity.

We report here the complete synthesis of the spin-labeled derivative of an antitumor ether phospholipid, 1-O-octadecyl-2-O-(4'-doxylpentyl)-rac-glycerol-3-phosphocholine. This also represents the first time that the synthesis of a nitroxide spin-labeled diether phospholipid is described. In vitro experiments showed that at micromolar concentrations, this new analog is readily incorporated into the plasma membranes of human HL60 and mouse E8/AK.D1 leukemic cells, and subsequently kills the cells. The availability of this new probe should permit the electron spin resonance spectroscopic approach to investigate ways by which anti-tumor ether phospholipids selectively destroy the tumor cells.     

Putative papain-related thiol proteases of positive-strand RNA viruses. Identification of rubi- and aphthovirus proteases and delineation of a novel conserved domain associated with proteases of rubi-, alpha- and coronaviruses.

A computer-assisted comparative analysis of the amino acid sequences of (putative) thiol proteases encoded by the genomes of several diverse groups of positive-stranded RNA viruses and distantly related to the family of cellular papain-like proteases is presented. A high level of similarity was detected between the leader protease of foot-and-mouth-disease virus and the protease of murine hepatitis coronavirus which cleaves the N-terminal p28 protein from the polyprotein. Statistically significant alignment of a portion of the rubella virus polyprotein with cellular papain-like proteases was obtained, leading to tentative identification of the papain-like protease as the enzyme mediating processing of the non-structural proteins of this virus. Specific grouping between the sequences of the proteases of alpha-viruses, and poty- and bymoviruses was revealed. It was noted that papain-like proteases of positive-stranded RNA viruses are much more variable both in their sequences and in genomic locations than chymotrypsin-related proteases found in the same virus class. A novel conserved domain of unknown function has also been identified which flanks the papain-like proteases of alpha-, rubi- and coronaviruses.     

Distribution of compatible solutes in the halophilic methanogenic archaebacteria.

Accumulation of compatible solutes, by uptake or de novo synthesis, enables bacteria to reduce the difference between osmotic potentials of the cell cytoplasm and the extracellular environment. To examine this process in the halophilic and halotolerant methanogenic archaebacteria, 14 strains were tested for the accumulation of compatible solutes in response to growth in various extracellular concentrations of NaCl. In external NaCl concentrations of 0.7 to 3.4 M, the halophilic methanogens accumulated K+ ion and low-molecular-weight organic compounds. beta-Glutamate was detected in two halotolerant strains that grew below 1.5 M NaCl. Two unusual beta-amino acids, N epsilon-acetyl-beta-lysine and beta-glutamine (3-aminoglutaramic acid), as well as L-alpha-glutamate were compatible solutes among all of these strains. De novo synthesis of glycine betaine was also detected in several strains of moderately and extremely halophilic methanogens. The zwitterionic compounds (beta-glutamine, N epsilon-acetyl-beta-lysine, and glycine betaine) and potassium were the predominant compatible solutes among the moderately and extremely halophilic methanogens. This is the first report of beta-glutamine as a compatible solute and de novo biosynthesis of glycine betaine in the methanogenic archaebacteria.     

Specific phosphorylation of a COOH-terminal site on the full-length form of the alpha 1 subunit of the skeletal muscle calcium channel by cAMP-dependent protein kinase.

The primary (alpha 1) subunit of purified skeletal muscle dihydropyridine-sensitive calcium channels is present in full-length (212 kDa) and truncated (190 kDa) forms which are both phosphorylated by cAMP-dependent protein kinase (cA-PK) in vitro. In the present study, phosphorylation of the purified calcium channel by cA-PK followed by immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and two-dimensional phosphopeptide mapping revealed differential phosphorylation of the related 190- and 212-kDa forms. The 190-kDa form of the alpha 1 subunit was phosphorylated on three major and three minor tryptic phosphopeptides; the 212-kDa form was phosphorylated on all six of these phosphopeptides plus two that were unique. Time course experiments showed that a single site on the COOH-terminal portion of the full-length form of the alpha 1 subunit is most intensely and rapidly (within 10 s) phosphorylated. Phosphorylation occurs almost exclusively on this COOH-terminal site unless harsh conditions such as treatment with denaturing detergents are employed to expose phosphorylation sites within the 190-kDa segment of the molecule. Elution of phosphopeptides from the second dimension chromatograph followed by immunoprecipitation with an anti-peptide antibody (anti-CP1) directed against the COOH-terminal amino acid sequence enabled us to identify this major phosphorylation site as serine 1854. The nearby consensus sites for cA-PK phosphorylation at serines 1757 and 1772 were phosphorylated only after denaturation or proteolytic cleavage. Phosphorylation of serine 1854 may play a pivotal role in the regulation of calcium channel function by cA-PK.