Abstract:Retinoid signaling system is composed of retinoic acids, retinol binding proteins (RBPs ), cellular retinol binding proteins (CRBPs), cellular retinoic acid binding proteins (CRABPs), retinoic acid nuclear receptors and retinoic acid responsible elements. This system has been proved to regulate expression of many functionillg genes, such as genes of CRABP- I,c-Fos, growth factor receptor, protein kinase C,etc. Therefore, the retinoid's role in morphogenesis during embryonic development and regulating the growth and differentiation of a wide varity of cell types throughout life of organism are involved in this signaling system.

Abstract:Chitinases, hydrolyzing specifically β-1,4 glucosidic band of chitin, play an important role in carbon cycle of nature, and have a wide distribution and a variety of functions.Chitnases are invovied in the growth, development of fungi and have a key role in plant protection against fungal pathogens. The present situation and the latest progress in chitinase research are reviewed, including the distributions, physical, chemical and catalytic properties, localization in cells and regulation of chitinases, and the latest progress in fungi and plant chitinases research are summerized briefly.

Abstract:At present, it is found that there are over 20 enzymes related to fruit development among which 14 mRNA increase. Eight enzymes can be induced by ethylene. Many ripening-related genes have been cloned,sequenced and located in the chromosomes. The expression of these enzymes can be inhibited by using antisense technology, thus disclosing the function of them in fruit ripening, and inhibiting the senescent process of tomato from molecular level. Seven antisense genes have been transfered to tomato. Antisense fruits keep fresh for 90～120 days in vitro.

Abstract:Carboxlesterases (EC3.1.1.1 ) can be inhibited by combining with organophosphorus compounds and classified into B-esterase.The enzymes are responsible for the hydrolysis of ester, thioester and amide bonds of many compounds although their natural substrate and physiological role are nuclear. Recently, it is found that purified carboxylesterase may play an important physiological role in biotransformation of drugs or xenobiotics and lipid metabolism.Human carboxylesterases consist of an important family of isoenzymes that have distinct biochemical characteristics with studies on the primary structure and gene sequence of many different isoenzymes.

Abstract:Apoptosis, an active process of cellular self-destruction involved in a variety of physiological and pathological conditions, can be induced by either oxidants or stimulators of cellular oxidative stress. Mild damages such as ionizing and ultraviolet radiation, hyperoxia,hyperthermia, infection etc, will injure the cell via reactive oxygen species (ROS), which may either react with the polyunsaturated fatty acids,leading to the formation of oxidized lipids, or activate certain genes related to cell death. As a result, the cell commits suicide following a sequence of biochemical change. bcl-2, one of the proto-oncogenes, was found to play a role in the regulation of apoptosis.

Abstract:In the extracellular plasmin system,the receptor for a urokinase plasminogen activator (uPAR) acts as an anchorage site for uPA on the cell surface where it modulates the activities of the extracellular plasmin system, has a function of internalizing uPA-inhibitors and other complexes, transmits the extracellular signals into cells and represents a new prognostic parameter and a promising approach for anti-invasive therapy in cancer.

Abstract:The human erythrocyte membraneskeleton protein 4.1 interacts with glycophorin C/D (GPC/D ). This interaction particularly determines the shape and the mechanical properties of the red cell. A number of workers have provided evidence for the interaction. Recent publication has reported that GPC/D provide major membrane binding sites for protein 4.1 in normal erythrocyte, and the sites are located on amino acid residues 82～98 of GPC and 61～77 of GPD.

Abstract:Retinol-binding protein (RBP) is a carrier transporting retinol (vitamin A), and is an important member of lipocalin family which can bind small hydrophobic substances. The studies of structure and function of RBP are given much attention by scientists. The progress in properties and structure of RBP is summarized, and the binding sites and structural feature of the interaction of RBP with transthyretin and receptor are discussed.

Abstract:Interleukin-2 receptorγchain(IL-ZRγc)is one of IL-2R subunits discovered about three years ago. It not only participates in the formation of high and medium affinity IL-2R complex, but also join in the formation of functional complexes of IL-4R,IL-7R,IL-9R and IL-15R, possibly IL-13R, serving as a member of cytokine receptor super family. IL-2Rγc gene's structure and function, the molecule structure and chromosome mapping have been elucidated. Abnormalities of IL-2Rγc and its signaling result in human X-linked severe combined immunodeficiency(XSCID).It is significant to explain the biological properties of IL-2Ryc in physiological and pathological condi-lions to understand the development, maturation and differentiation of lymphocytes and immunoresponse etc.

Abstract:Cyclic ADP-ribose (cADPR) is a novel endogenous metabolite of nicotinamide adenine dinucleotide (NAD⁺), and is a recently discovered second messenger. cADPR is active in mobilizing intracellular Ca²⁺ in invertebrate as well as mammalian cells. The mechanism of releasing Ca²⁺ from internal pool (s) has been studied. cADPR may bind its receptor, which in turn induces the release of Ca²⁺ from cADPRsensitive Ca²⁺ pool(s) through ryanodine receptor or ryanodine receptor-like mediated Ca²⁺ channel. In addition,a possible intracellular signal transduction pathway involving nitric oxide(NO)，cyclic guanylic acid(cGMP ) and cADPR has been suggested to exist in various cells.

Abstract:Transgene, a concept becoming more and more widely used in modern molecular biology research, has been used to refer to all the foreign genes which were reconstructed and transfered by genetic engineering strategies, and then stably integrated into the genomes of higher eukaryotic cells. The types of transgene structure, its genetic behavior in the recipient cells, the characteristics of transgene expression,the factors involved in the expression regulation and the biological effects of the transgenes are reviewed. The unknown problems in the transgenie research are illustrated. The necessity of doing the systematical research about the molecular biological characteristics of the transgenes is pointed out.

Abstract:With DNA lesions induced by environmental physical and chemical factors, actively transcribed genes and DNA transcribed strands were preferentially repaired.This preferential DNA repair directly connected with the process of gene transcription.A transcription-repair coupling factor (TRCF) encoded by mdf gene has been identified and isolated in E. coli. TRCF is a DNA binding protein with ATPase activity. In eukaryotes, some DNA repair proteins were found to be involved in transcription. For example, the largest subunit of general transcription factor TFⅡH, p89, is the encoding product of human excision repair gene ERCC-3 .And the excision repair gene RAD3 of yeast encodes the largest subunit of transcription factor b, p85.

Abstract:Photosynthetic process should include both the process of light energy utilization and the process of light energy dissipation. In the latter process, besides the biochemical mechanisms of photorespiration and Mehler reaction,there are also some biophysical processes. These processes can be summarized into follwing three aspects: (1) Energy dissipation through electric cycle around PSⅡ. This cycle includes PS Ⅱreaction center, plastoquinone, and cytochrome b-559. This mechanism can recombine with the charge separated PSⅡ center, so that prevent the oxidation of chlorophyll induced by the longer existence of oxidative P680⁺.(2)Heat dissipation correlated with the thylakoid membrane energization and xanthophyll cycle. This mechanism exists in LHCⅡ，and responses quickly at relatively lower excess light stress (3) Heat dissipation via photosystem Ⅱ hetero-geneity and the turnover of D1 protein. This mechanism bases on the hypothesis that there are two kinds of photosystem Ⅱ.One is photosyn-thetic active with higher linear electron transport and higher fluorescence emission but lower heat dissipation. The other is photosynthetic inactive with lower linear electron transport, lower fluo-rescence' emission and higher heat dissipation. The latter is called dissipative PSⅡ .This dissipative PSⅡ can be reactive directly without protein synthesis or indirectly through D1 protein turnover process.

Abstract:hEPO cDNA without non-coding ration was recombined with retrovirus vector pLXSN, pLNCX through DNA recombinant techniques. After these two recombinant plasmids were transfeeted the retrovirus packaging cell line PA317, G418 resistant clones could produce defective EPO cDNA recombinant retrovirus successfully which could infect NIH 3T3 target cells and make them form typical resistant clones in G418 selective medium. Moreover, in the genome of these infected target cells, hEPO cDNA was successfully integrated and expressed.

Abstract:Heat shock induced significant increase of the SOD and CAT activities in silkworm of various ages, such as at 40℃ the induced SOD activity was maximal, where both the activities of CuZn-SOD and MnSOD were also increased. Alter exposure at 36℃ for 1h,GSH-Px activity was decreased, but it was increased at 40℃. Among the different regions of silkworm, the activities of SOD and CAT have great diversities in the order of priorities:thoracicoabdominal region, head region,posterior silkgland. Heat shock also had different influences on the activities of the antioxidative enzymes of different regions to adapt different physiological states of silkworm. The antioxidases work cooperative interaction, so that the normal physiological functions are maintained.

Abstract:A dicistronic expression vector in E.coli has been constructed. The vector contains glutathione S-transferase (GST) gene as the first cistron, followed successively with translational enhancer, SD sequence, stop codon, start codon and multiple restriction enzyme sites for cloning(MCS).3'-terminal framgents of human bone morphogenetic protein (hBMP)gene 2A and 3 were inserted into the MCS respectively. After induction, un fused hBMP2A and hBMP3 expressed and occupied 10% and 15% of the total cell protein respectively. The GST gene in the plasmids were further shortened from 660 by to 206 bp. The expression level of hBMP2A and hBMP3 were double by the plasmids containing short GST gene as compared to that of the corresponding plasmids with large GST gene.

Abstract:Five ligands containing benzimidazolyl and 32 compounds of their containing copper (Ⅱ), iron(Ⅲ), manganese (Ⅱ), cobalt (Ⅱ) have been synthesized based on the active site structures of natural superoxide dismutase (SOD), respectively. It has been shown that these compounds possess mimetic SOD activities by spectroscopic and electrochemical measurements. The concentrations of 50% inhibition (IC50) are within 10-6～10-8mol·L-1. The rate constants (kq) of catalytic dismutation of superoxide radicals (O-·2) are in the range of 106～108mol-1·L·s-1.Simultaneously it has been observed that a several mimetic compounds of then have antineoplastic activities and increasing antifreezing effect of rices.

Abstract:The C1q receptor (C1qR) on the human T lymphocyte line Jurkat cells was demonstrated and characterized. Cell-ELISA showed that Jurkat cells are able to bind exogenous C1q and recognized by the anti-C1qRantibody 112. FCM analysis indicated that the binding of FITC-C1q to Jurkat cells is blocked by an excess of unlabelled C1q.Quantitative binding studies with monomeric ¹²⁵I-C1q showed a specific, dose-dependent,saturable and reversible binding involving specific membrane receptors on Jurkat cells, Goldstein analysis and Hill plot of C1q binding showed 1.1×10⁶ binding sites per cell with an average affinity of 1.5×10⁷mol^-1 and a Hill number of 0.9643 at normal ionic strength(I=0 .15) and temperature(37℃). The experiment with the anti-Clq monoclonal antibody A₄，which recognizes the collagen-like region (CLR) of C1q, established that it is via its CLR that C1q binds to Jurkat cell receptors. Western blotting with the anti-C1qR antibody 112 revealed that the C1qR on Jurkat cells is a membrane protein of 70 ku.

Abstract:A cDNA library of Wistar rat brain was constructed with a highly effcient and simplified method. The template Poly (A)⁺-RNA was extracted from Wistar rat brain. The first strand of cDNA was synthesized by SuperScript RNase H^- reverse transcriptase with the oligo (dT)₁₅ primer which contains Not I site. After the poly (A)⁺ -RNA was removed with E. coli RNase H, the second strand was synthesized by means of E. coli DNA polymerase I, E. coli DNA ligase and T4 DNA polymerase.Then Sal I adapter was added and the cDNA digested with Not I .Half of the cDNA was inserted into plasmid pSPORT I and transformed E .coli DH 5a. The other half was stored at -20℃. It was shown that the cDNA length ranged from 100 to 10 000 bp. Using this cDNA library as a template, four genes have been amplified successfully. They are glutamic acid decarboxylase (GAD, 1800 bp)，neuron-specific enolase (NSE, 1340 bp)，T3 receptor(1230 bp) and cholecystokinin(CCK, 345 bp).The method for storage of the cDNA library which can be kept for a longer period was also developed.

Abstract:An improved procedure by using ureagradiont gel for protein folding and unfolding investigation is provided. Some key techniques such as urea gradient homogeneity, gel viscosity and gel edge effects have been discussed. An inverse gradient of glycerol is used to compensate for the small effects of urea on the electrophoretic mobilities of both folded and unfolded proteins. The glycerol gradient used here of 15% at 0mol/L urea to 0% at 8 mol/L urea was designed to give a constant mobility of creatine kinase at all urea concentrations. The gel was photopolymerized in the presence of riboflavin. 5% stacking gel and sample combs were also used on urea gradient gel to improve the sample pattern.

Abstract:The thinbarbituric acid(TBA)fluorescence spectrophotometry of lipoperoxides(LPO),at present used for research,has been improved. This assay of serum LPO involves a hydrolysis in a diluted glacial acetic acid solution at 100℃ for 60 min and the hydrolysis product malondialdehyde (MDA) forms complex with TBA the methanol precipitation of serumproteins reduces nonspecific interference.The fluorecence intensity of the MDA-TBA complex is measured at excitation wavelength 515nm and emmission wavelength 550nm. The method is simple,rapid, accurate and steady. The fluorescence intensity is positively correlative to the LPO concentration in the range of 0～20μmol/L. The minimum detection limit is 0.16μmol/L.The average recovery rate is 105.08%. Precision(CV) is 4.23%.

Abstract:A sensitive and precise method for simultaneous determination of some major cholesterol autoxidation products(COPs)was described. The method was based on high performance liquid chromatography (HPLC) with 6-chlorostigmasterol as internal standard.After saponification and extraction, the COPs were derivatized into benzoates for measurement by HPLC with ultraviolet detection. Each product gave a linear response(r＞0.9990) over a concentration range of 0.312～10.000 mg/L. The intra-and inter-assay co-efficients of variation was 2.15%～5.40% and 1.23%～3 .70%, respectively. This method was successfully applied to the determination of COPs in cholesterol standard reference material and in human serum.

Abstract:A simple and economical staining method for isozyme is described. Filter paper (treated with 0.4% agarose) was soaked in isozyme staining solution for half an hour and was used to stain the isozymes after PAGE, then move the gel and filter paper to a covered plastic box.The staining time would be longer than normal. After staining, put the gel and filter paper into fixing solution and remove the filter paper with tweezers carefully.

Abstract:Hydroxyl radicals from Fenton reaction can react with salicylate to form 2,3-dihydroxybenzoate.The quantitative analysis of hydroxyl radicals can be done through the colorimetric determination of 2,3 -dihydroxybenzoate.The determination condition has been studied and a best determination program has been obtained. The test indicated that hydroxyl radicals from this system could be scavenged by reutin and quercitin.This system can be used as a convenient method for the selection of hydroxyl radical scavenger.

Abstract:A very simple method to determine the activity of LD isoenzyme Ⅰ by using αchymotrypsin and guanidine has been developed.LD-3～LD-5 can be completely inactivated and LD-2 can be partially inactivated byαchymotrypsin.Guanidine can further completely inactivate LD-2. This method has been used in automatic analyzer. The coefficient of variation of the proteolytic method is among 2.7% ～4.4%.Results obtained by the present method correlates with those by the electrophoresis method (r=0.992, y=0.967x-1.957). In the present assay system, the reference value for LD-1 activity in healthy people ranges from 29.78～59.26 U/L. The study showed that the selective measurement of LD-1 isoenzyme method is rapid and accurate. It has great clinical significance.