Abstract:Carbohvdrates have many important biological functions in organism. It has been demonstrated that structural characteristics of carbohvdrates provide important clues for the understanding of cell and molecule recognition process where sugar is mainly involved in. It is concentrated on the concepts of oligosaccharide structure,the latest theoretical development of this subject,as well as some methods often used in this field.It is generally considered that one of the theoretical directions is to exhibit the interactions between oligosaccharides and proteins, and the structure and function of oligosaccharide in glycoprotein.

Abstract:Secretive proteins in E.coli, which are located in the inner membrane,the outer membrane,the periplasmic space or the environment,have a structure containing the secretion signal on the N or C terminal.These two sorts of proteins elbow through the inner membrane with the help of two series of distinguishable protein factors and realize their final position by an unelucidated mechanism. The molecule containing its signal peptide on the N terminal is assisted by protein factors of the Sec family when rushing through the cytoplasma membrane. The leading peptide might be cut off in the process. ATP and the electrical potential supply the energy for the secretion. The molecule which has secretion signal on its C terminal is helped by the Hly family members to pass the inner and outer membrave at the same time while omitting the periplasmic space.

Abstract:The methylation and demethylation of cytosine in CpG dinucleotide plays an important role in regulation of mammalian gene expression.There are two kinds of promoters in mammalian genome:CpG-island promoters and CpG-deficient promoters.Two protein factors influence gene expression by interacting with methylated CpGs.CpG islands also have useful applications in genome analysis.

Abstract:The apolipoprotein A-Ⅰis an important plasma protein which plays an essential role in transportation and metabolism of lipid,and its gene expression shows evident tissue-specificity,species-specificity and developmental stage-specificity.By the cooperation of the cis-acting elements,eg. the liver-specific-enhancer at the 5' upstream region and the positive or negative transcriptional factors such as ARP-1,HNF-4,RXRα,the apo A-Ⅰ gene is regulated to express specifically.

Abstract:Pyrophosphate:fructose-6-phosphate 1-phosphotransferase (PFP) catalyzes the reversible conversion of fructose-6-phosphate and fructose-1,6-bisphosphate,The enzyme generally exists in kinds of higher plants and some of microorganisms.Some advance in the research of PFP after 1990 was reviewed.It contains the types and the constitution of subunits,the active center,the substrate specificity,the regulation of activity and the fuction of PFP.

Abstract:Protein specific-cleavage reagents refer to those cHemical tools which can cut off peptide-bonds specifically.These regents can be divided into two classes. The first is called oxidative cleavage reagents. Oxidative cleavage has the property of stereo-specificity. Only the peptide bonds which close to cleavage system in tertiary structure are cleaved. The second is called hydrolytic cleavage reagents.These complexes can catalyze the hydrolysis of specific peptide bonds directed by protein sequence specificity.Protein specific-cleavage regents are useful for protein sequence analysis，for studies on the relationship between structure and function of protein and for synthesis of new chemical therapy drugs. The development of these reagents will improve the studies on protein chemistry and other relative subjects.

Abstract:Electronic communication through Internet has provided on-line computer users an effective way for information exchange. For molecular biologists,they can not only use the electronic mail(e-mail)system to send and receive message as fast as fax,but also more importantly,can access large numbers of new moleuclar biology databases and softwares. They can perform various sorts of sequence analysis tasks,including homology search against databases,gene coding region identification and protein secondary structurean analysis，etc. A database，such as GeneBank，can be accessed through the following ways:(1) e-mail file servers，(2) file transfer protocol (FTP)，and <3) Gopher，wide area information server ( WAIS) or world-wide web (WWW).The BIOSCI bulletin board，specially for the interest of molecular biologists，gives great convenience for molecular biologists to hold discussions of scientific topics， ask for others’help and communicate with database staffs.

Abstract:The effect of intron on gene expression in transgenic animal is reviewed.The difference between natural and heterologous introns in increasing gene expression efficiency is analyzed and three possible mechanisms which introns promote gene expression in transgenic animal are discussed.It is necessary to consider intron effects on constructing expression vectors of producing transgenic animal.

Abstract:The research on the protein blotting was fruitful during the past few years. This review summarizes the literature relating to the application of protein blotting in the fields as following:solid-phase sequence analysis of proteins, clinical differential diagnosis of various virulence antigens or antibodies in human serum or urine,capillary column chromatography and preparative capillary electrophoresis of macromolecular biomaterials,purification of monoclone antibodies or monoepitopic antibodies,and detection of proteins and enzymes using various antibodies or ligands.

Abstract:According to the rules of eukaryotic gene expression and regulation,two versatile eukaroytic expression vectors(pMAML1-dhfr and pMAML2-dhfr) originated from pSV2-dhfr were constructed.They both have a CMV immediate early promoter/enhancer and consist of two expression units of parallel or opposite orientation.Using firefly luciferase gene as reporter gene and β-galactosidase gene as internal control,their effects on luciferase expression were studied in COS-7 transient expression system.The relative strength of their cis-elements were compared with those in pSV2-dhfr.

Abstract:Mdrl gene contributes to multidrug resistance.Because of the level of Mdrl gene expression is correlated with the response of chemotherapy,it is a valuable method to measure the expression level of individual patients. The cDNA cloning of the human Mdrl gene has made it possible to measure levels of Mdrl RNA with hybridization in human cancer cells. A special part of Mdrl cDNA was obtained by use of RT-pCR and inserting it into pUC18 vector.The DNA sequencing result is identical with the sequence of Mdrl cDNA reported. This probe can be used to detect the level of Mdrl gene expression in clinical specimen. The measurements can be useful in the design of chemotherapeutic protocols for certain tumors.

Abstract:Maleimide was used as spin label for studying the effect of hypoxia on rat cerebral cortex neurons.Results showed that hypoxia induced the lipid peroxidation in cerebral cortex cells and increased the formation of LPO. By comparing the characteristics of ESR spectra,it was found that values of τ_c were significantly higher in hypoxic group than that in control(P<0.01).The increase in the ratio of h₀/h_-1 was well correlated with the enhance in hypoxia group. It was also found that MT could inhibit the lipidation in cerebral cortex cells.

Abstract:Methoxypolyethylene glycol (Mr 5000),activated by cyanuric chloride and nitrophenol carbonate respectively,was used to modify subtilisin Carlsberg. The enzyme after PEG-modification maintained its catalytic activity both in aqueous solution and in 0rganic solvents,and an enhancement in activity and stability in aqueous solution was achieved:the k_cat increased accompanied with a lower activation energy,while K_m was not changed;the stability of the enzyme against both temperature and pH was greatly enhanced，but the optimal reaction temperature was unchanged. The pH dependence of the modified and unmodified subtilisin has also been compared.

Abstract:Ca²⁺-ATPase from rabbit skeletal muscle sarcoplasmic reticulum vesicles was solubilized by nonionic detergent C₁₂E₈ and purified in a reactive red-120 agrose affinity column.Determined by 7.5% SDS-PAGE,the purity of Ca²⁺-ATPase was increased from 65% to 99% and the purified Ca²⁺-ATPase exhibited higher ATP hydrolysis activity.

Abstract:A Viscum coloratum lectin (VCL) was first separated from extracts of the stems and leaves of Viscum coloratum Chinese,an ordinary traditional medicine beijisheng,by affinity chromatography on acid-treated Sepharose 6B and gel filtration on Sephacryl S-200,with Mr=52 000,pI=10.5.The LD₅₀ was 4.4μg/kg for mice by intravenous injection,It's a toxic protein obtained from the plant with higher toxicity to mice. The crude extracts of the poant also have strong toxicity,because it's LD₅₀ was 200 mg/kg for mice by intraperitoneal injection and to be expressed as the amount of dry materials.

Abstract:The Sprague-Dawley rats with postnatal 3 d were collected.The hypetphenylalaninemia was induced by intraperitoneal injection with phenylalanine.Fluorospectrophotometry was applied to quantive determination of norepinephrine(NE),dopamine(DA)and serotonin(5-HT)in the cerebral cortex and its synaptosome of the rats. Behavior in the rats was observed by Y-maze learning.The results showed that compare with the control,the contents of NE,DA and 5-HT were decreased over 38.6%～67.4% in the cortex of the hyperphenylalaninemic rats and decreased over 51.9%～70.2% in the synaptosome of the cortex. Y-maze learning ability in the rats was decreased apparently. The results suggest that the mental retardation of PKU is in close correlative with decrease of some monoamine transmitter contents in the cortex and its synaptosome.

Abstract:Residual cell DNA(RC DNA) in the products of recombinant human intederon γ(IFN-γ)was detected by hybridization with digoxigenin-labeled total DNA of E.coli DH5α-pBV220/IFN-γ as probes,The result showed a great disparity between two DNA standards in colour;thus indicating that high protein amount interfere seriously in the detection of trace RC DNA and that the DNA standard supplied with IFN-γ is more reasonable than the homogeneous one.The sensitivity of the method is 4 pg and RC DNA amount existed in each dose of all samples is less than 100 pg，which satisfied WHO requirements.

Abstract:A convenient and efficient procedure for isolation of rice HMW DNA bad been developed.Etiolated seedings were ground into the fine powder with a pestle and mortar under liquid nitrogen,then extracted with a protective medium,Filtrate was layered on discontinuous sucrose gradient,then the purified nuclei were embeded in agarose gel.After proteinase digestion,the HMW DNA was released. Pulsed-field gel electrophoresis showed that the sample size ranges from 200 kb to 3 Mb and in the majority of 2.2 Mb. Rice YAC library was constructed successfully, using these easily digestable DNA preparation.

Abstract:An algorithm,called searching sequence-specific ions,is proposed here for interpretation of mass spectra of unknown polypeptide.This program is composed of three parts:searching,scoring and merging. The method successfully interpreted some unknown polypeptides’mass spectra. One of the major advantages of this program over algorithms described earlier is its scoring ability which can rank the confidence of every amino acid residues in the interpreted polypeptide.It greatly facilitates the determination of the amino acid sequence and provides a pathway for the application of mass spectra to biology.

Abstract:Phospholipid(PL)has higher medical and nutritional values and widely applied in medical,food,Chemical industry field etc. The natural PL of yolk powder was extracted by supercritical fluid CO₂ extraction(SFE-CO₂)technique. The phosphorus,nitrogen and PL contents,the N/P molar ratio,the triglyceride and cholesterol of the extraction were measured by means of biochemical method,thin layer chromatography,and spectral analysis. The results showed that extracted yolk PL is 95%in purity and its N/P molar ratio is 1.003. So the SFE-CO₂ technique can be used to obtain yolk PL with higher purity quality.

Abstract:Twenty murine hybridomas were established producing monoclonal antibodies against TSH.Their immunoglobulin subclasses were IgG or IgM. The titers of T₇₄A₁₀ and T₇₁B₁₁ were 1:50 000～1:150 000 and affinity constants were 7. 15 ×10⁹L/mol and 8.75 ×10⁹L/mol respectively. The cross reactivity with HCG,FSH and LH were less than 1.1×10^-6%,0.01% and 0.016% respectively. TSH IRMA was established using T₇₁B₁₁ and T₇₄A₁₀ as tracers or solid phases.

Abstract:Two partial antagonists of human interleukin-2(IL-2):15 Val-IL-2,126Asp-IL-2 and an IL-2 receptor a subunit binding deficient mutant 62Leu-IL-2 have been obtained by site-directed mutagenesis, 62Leu-IL-2 could exhibit significant stimulation on CTLL-2 cells. When 15Val-IL-2 or l26Asp-IL-2 was incubated together with CTLL-2 cells in addition to 62Leu-IL-2,the stimulative ability of 62Leu-IL-2 was distinctly inhibited.In consideration with the interaction of IL-2 with IL-2 receptor subunits,15Val-IL-2 or l26Asp-IL-2 can be used for the primary determination on receptor subunit binding ability of IL-2 mutants. Furthermore，this idea may also be applied in some other ligand-receptor systerns.

Abstract:Under the high voltage electrostatic field(HVEF),radishes were planted in the cultural solution containing ³²P and eight kinds of inorganic ions. The analytic results of the distribution of ³²P and ions showed that the radiation intensities of ³²P in the upper layer of soil and cultural solution were 15.19% and 63.13% higher than that of the control group, but in the lower layer were 18.39% and 29.05% lower than that of control group respectivel.The ³²P intensity in radish leaf was 66.57% higher than that in control leaf, but in root it was 8.27% less than that in control one. Also，the cations in the cultural solution under HVFF tended to move to upper layer of the solution，while those in control one tended to distribute to lower layer. Results indicate that the promoting effects of HVEF on ion absorption of the plant (up ground parts) are related to the upward movement of cations under the HVEF.

Abstract:General reverse transcription polymerase chain reaction(RT-PCR)is a complicated process with low efficiency.And high quality mRNA is required and the mRNA is easily destroyed by RNase.The hybridoma cells were fixed with 10% formaldehyde solution in normal saline and permeabilised by 0.5% Nonidet P-40 in water. After the mRNA was reversely transcribed to cDNA and the cDNA was amplified by polymerase chain reaction(PCR),a specific heavy chain variable region gene(VH)of immunoglobulin with length of about 350 bp,being consistent with the product amplified by normal RT-PCR，was obtained. This technique could be applied to prepare specific structure gene fragmenu，to link and amplify chimeric protein genes and to construct human antibody lihraries.

Abstract:Coomassie blue is a routine dye of polyacrylamide gel electrophoresis. With the adsorption of dye to nitrocellular filter,substantively stain the protein bands on NCF with low concentration coomassie blue (0.025%) solution, through repeated tests,it proves to be an available method for staining non-specific protein bands of Western blot on NCF.