Abstract:Kinesin is a microtubule-dependent motor protein, which can hydrolyze ATP and move along microtubule. The structure, functions, and activity regulation of kinesin are summarized.

Abstract:A tRNA-directed transcription antitermination mechanism is common in Gram-positive bacteria, regulating the expression of aminoacyl-tRNA synthetase and amino acid biosynthesis genes. When the level of an amino acid decreases, the cognate uncharged-tRNA accumulates. Uncharged-tRNA stimulates the conformation of mRNA leader region to change from a terminator structure to an antiterminator structure by interaction of two sites: the anticodon and 3′ acceptor end of tRNA interact with the specifier sequence and the T-box in mRNA leader, respectively. This procedure promotes the readthrough and the expression of the relative genes.

Abstract:Optimization of protein crystallization is going to be an important method to obtain protein crystals in high quality. Regarding different crystallization methods, some optimization techniques were attempted and found effective to some extent. However, due to the variety and complexity of protein crystallization, these techniques have not been used in practice. These attempts are introduced and some problems are discussed.

Abstract:The proteins expressed by the glutathione S-transferase(GST) supergene family which catalyze the conjugation of endogenous or exogenous electrophiles with glutathione(GSH) are a family of detoxicating proteins,the gene expression of which is regulated by many sorts of compounds through different mechanisms. A brief review for the gene structure and regulation mechanisms associated with the expression of GSTs,and the action of oxidative stress in the regulation of GST gene expression was made.

Abstract:Deamination of bases is regarded as the major factor for mutation in DNA and it will induce transition mutation if the products of deamination have not heen repaired. Now a new sensitive genetic assay to determine quanti-tatively deamination of bases in DNA special site has been introduced to understand the relationship between DNA structure and its chemical activities. The assay is based on reversion of a mutant of CCC proline coding sequence which is located in Lac Z α gene of bacteriophage M13mp2 from a colorless to blue plaque phenotype. This approach is highly sensitive; deamination of a single cytosine residue in 10⁵ M13mp2 DNA molecules can be detected. Besides, the kinetic rate constant of the reaction and the activation energy of deamination can be calculated.

Abstract:The BNLF-1 gene located in U₅-TR region of Epstein-Barr virus genome encodes a latent membrane protein (LMP-1). As the protein can transform B cells and plays a key role in the carcinogenesis of EB virus, so it has become the “hot spot” of studying for the diseases relavance to EB virus, such as nasopharyngeal carcinoma, Burkitt's lymphoma, Hodgkins disease etc, and also the molecular biology of EB virus. A series of achievements have been achieved, the progress in following aspects are reviewed: 1. the structure and expressing regulation of BNLF-1 gene; 2. the structure and biochemical function of LMP-1 protein; 3. the biological function of LMP-1; 4. looking forward to the future.

Abstract:Nov gene is a novel cellular oncogene which might play an important role in cell proliferation, oncogenesis and embryonic development. The discovery,structure and function, expression and regulation of the nov gene, and the relation to its relevant genes are described.

Abstract:As an important messenger, intracellular free calcium can modulate many cellular functions. Calcium stores, endoplasmic reticulum and sarcoplasmic reticulum, play important functions in controlling the level of intracellular calcium. The activities of calcium release channel on these calcium stores, ryanodine receptor and inositol trisphosphate receptor, are affected by several factors. FK506, an immunosuppressive drug, can specifically bind to a cytosolic receptor with molecular weight of about 12 ku, namely, FK506-binding protein (FKBP12). In vivo, FKBP12 maintains a tight association with calcium release channel and forms a complex. This interaction plays important roles in modulating calcium release channels.

Abstract:The recent development of systems for the expression of heterologous proteins on the surface of microorganism has stimulated considerable interest in practical applications.A comprehensive description is given on the construction of expressive vector for surface presentation on microorganisms which include bacteria and yeast, and the applications of these systems.

Abstract:Because of the structural similarity to rhodopsin, bacteriorhodopsin is characterized by some visual response properties. With electrophoresis method, oriented purple membrane films are deposited on stainless steel electrode to construct a photoreceptor with the structure of stainless steel/purple membrane/gel/copper electrode. As illuminated by modulated light, the photoreceptor gives rise to a differential response. The dependencies of the photoreceptor's photovoltages on the modulating frequency and the incident light power are measured. The analogy between the bacteriorhodopsin's response to modulated light and the visual flash and brightness are compared and discussed.

Abstract:Rat liver ribosomal RNAs on surfaces of mica were imaged by atomic force microscope (AFM) under ambient condition. A number of images of 28S-5.8S、18S、5S rRNAs were obtained directly. The rRNAs were prepared by thawing the solution of low concentration of ribosomes repeatedly to crumble the ribosomes. The rRNAs were scattered on surface of mica very well. The rRNAs prepared by this method were always in three forms when they were scattered on surface of mica. The structures of the three forms of rRNAs were consistent with the established models by computer for 28S-5.8S、18S、5S rRNAs respectively. The result supports the models of the secondary structures of rRNAs considered by the thermodynamic principle. It is demonstrated that AFM could provide valuable three-dimensional information of rRNAs.

Abstract:Two conjugates of R-phycoerythrin (R-PE) and C-phycocyanin (C-PC) were synthesized through a coupling agent, N-succinmidyl 3-(2-pyridyldithio)-propionate and the alternation of the ratio of R-PE to C-PC. Their ratio of R-PE to C-PC were determined by absorption spectra. One is 6∶1, the other is 2∶1. The phenomena of intramolecular energy transfer were characterized. The calculated results showed that the efficiency of energy transfer from R-PE to C-PC was 63% and 88% respectively. The efficiency of energy transfer is better. When the disulfide bridge between R-PE and C-PC was reduced by DTT, the energy transfer was stopped. The phenomena further verified the intramolecular energy transfer from R-PE to C-PC.

Abstract:By culturing mouse macrophages in vitro, The inhibitory effect of L-NNA on the synthesis nitric oxide (NO) was investigated, which was induced by IFN-γ in macrophages. It was found that L-NNA could inhibit the synthesis of NO, the inhibition was related to L-NNA dose, and L-arginine could reverse the inhibition. The results suggest that L-NNA likely competitively combined with the activate site of inducible nitric oxide synthase (iNOS), that inhibited the synthesis of NO from L-arginine pathway in macrophage.

Abstract:Modulation of HMBA on cAMP-PKA and DAG-PKC signal pathways in the cell cycle of MGc80-3 cells showed that: 1.there were positive and negative regulation between them; 2.signal regulation was different in the cell cycle. G1 phase was the most sensitive one among the four phases, cAMP level and PKA activity were increased by 102% and 348%, respectively, as compared with the control; while DAG content and PKC activity were decreased by 51.45 and 32.3%, respectively, as against the control. G2 phase was the second sensitive phase. Effects of HMBA on the signal regulation in M phase were not found. Changes of signal transduction in S phase were different to others.

Abstract:Interleukin-6 receptor (IL-6R) is a member of the hematopoietin receptor superfamily which has its common conservative structure “the cytokine binding domain (CBD)”. CBD is the functional domain of the extracellular region of IL-6R, because only this domain of IL-6R is responsible for IL-6-binding and for IL-6 signal transduction through gp130. It is proposed that the β-sheets folding motif of the IL-6R CBD is very similar to that seen in the crystal structure of human growth hormone receptor (hGH-R), which also belongs to the cytokine receptor family, and CD4. By means of computer-guided homology modeling techniques, the three-dimensional (3D) structures of hGH-R and CD₄ were used as template protein to predict the 3D-structure of the functional domain (residue 106～322) of hIL-6R. The characteristics of the conservative structure-conformation in CBD of hIL-6R were described. The model may provide for the interpretation of the results obtained with introducing site-directed mutation into soluble IL-6R and the 3D-quantitative analysis on the structure-function relationship of IL-6R functional domain.

Abstract:Peroxynitrite is a powerful cytotoxic species formed by the rapid reaction between nitric oxide and superoxide. The nitration of phenolics such as tyrosine by peroxynitrite is one of important paths peroxyntrite damaging biological systems. The effects of ferric citrate and ferric oxalate on the nitration of tyrosine by peroxynitrite have been studied. At physiological pH, ferric citrate and ferric oxalate have no effects on the reaction. At weakly acidic pH the reaction can be catalyzed by ferric citrate and ferric oxalate. The cause of the effects of pH on the catalytic activity of ferric chelates has been discussed.

Abstract:A bifuctional anti-HBsAg-alkaline phosphatase fusion protein expression vector pHBFAP was constructed by attaching the PCR cloned E.coli alkaline phosphatase gene to the C-terminal of the anti-HBsAg Fd fragment gene. E.coli XL1-Blue was transformed with pHBFAP, and induced with IPTG. The HBsAg banding ability and the alkaline phosphatase catalytic activity were detected by using ELISA in the induced bacterial supernatant thus indicating that the anti-HBsAg-alkaline phosphatase bifunctional antibody was expressed successfully in E.coli.

Abstract:A strategy for cloning human immunoglobulin genes with antigen in vitro immunization and RT-PCR was established. Colorectal carcinoma-associated antigen CA-Hb3 were purified through a monoclonal antibody Hb3-Sepharose 4B affinity column and analyzed by SDS-PAGE and Western blot. Peripheral blood lymphocytes (PBL) from 10 ml blood of a patient with colorectal carcinoma were immunized with CA-Hb3, rhIL-2 and pokeweed mitogen. The lymphoblast-like cells and colonies could been seen after immunization. The amounts of total RNA from the immunized PBL are 2.5 times more than that from the non-immunized. Human immunoglobulin, VH-CH1 (IgG) and VL-CL (κ), genes were amplified with RT-PCR with the above total RNA or mRNA as templates. The products of human immunoglobulin genes from the immunized PBL are 1.3 times more than that from the non-immunized. This strategy would be used for humanizing mouse-original monoclonal antibodies.

Abstract:Trace amount of free amino acids in brain microdialysates was separated and determinated with derivative of fluorescein isothiocyanate (FITC) using the home-made microdialysis probes and biochemical sampling unit for living animal as well as capillary electrophoresis system with intensified charge-coupled device(ICCD)-laser induced fluorescence detector. The concentration of free amino acids in microdialysates was 10^-8～10^-6 mol/L with 5 μl sample. The change of free amino acids was monitored in vivo in the hippocampus of freely moving rats before and after operational learning. These experiments suggest that the sampling and determination system can be used for analysis of amino acids in brain microdialysates.

Abstract:A 29 ku protein, the sensory nerve-specific protein was isolated and purified from rabbit spinal ganglion and its fibers by anion exchange chromatography using DEAE-Sephacel and gel filtration HPLC. The purity was extiomatd to be over 80% by UV scanning. Western blot demonstrated that it immunoreacts with anti-rabbit the 29 ku protein monoclonal antibody. The stability also has been observed.

Abstract:In order to clone cDNAs coding for proteins specially binding to NF-IL6's 3′UTR, a phagemid expression library was constructed from cDNAs of revertant RR cells. The termination codons of those cloned cDNAs were largely removed by restricted exoⅢ enzyme digestion, in order to facilitate the expression of cDNA as fusion proteins with the phage gene Ⅲ. Examinations of this library showed that the library includes various lengths of cDNA inserts and it can express exogenous cDNA.

Abstract:The killing effect of photoexcited TiO₂ particles on U937 cells has been studied. DNA agarose gel electrophoresis shows that photoexcited TiO₂ particles can damage DNA, leading to the death of cells. So a new assumption of the way to kill cancer cells is proposed.

Abstract:Clinical biochemical items such as alanine amino-transferase(ALT), Creatinine(Cr), total protein(TP) in serum were analyzed by using ZS-3 semi-automatic biochemical analyzer. The results show that the machine had a good precision. The mean intra-assay deviation CV was under 5% and mean inter-assay deviation CV was under 9%. The average recovery was 95%～105%. When the drawn liquid volume was over 500 μl, the cross contamination could be controled under 5%～2%.

Abstract:BIA technology is used here to monitoring the key processes in molecular biology including gene assembly; DNA elongation; specific cleavage and hybridization. No labelling of the DNA or nucleotides is required, and the kinetic parameters may be estimated for the interaction processes.