Abstract:The ras gene has attracted great attention ever since it has been discovered having a relationship to cancer.Scientists not only know nowadays the mechanism about how ras gene results in cancer but also have a clear understanding about the relationship between Ras protein and the pathway of phosphorylation.In addition,the research about the signal transduction pathway which has something to do with the Ras protein leads to a more detailed understanding about the regulation of information communication in cells. Further more，the signal transduction pathways of Ras and of other proteins interact with each other. For example，the Ras pathway can be activated by the αβ dimer of G protein. Therefore，it is extremely necessary to study the Ras pathway，which will throw great insight on the regulation of Ras itself and the signal transduction on the cell level.

Abstract:Interleukin 13(IL-13)is a recently described novel cytokine produced by activated helper T cells. IL-13 protein is secreted mainly in unglycosylated form with molecular mass of about 10 ku.The mature ILs-13 of human and mouse consist of 112 and 111 amino acid residues respectively.IL-13 not only regulates the growth,surface antigen expression,and cytokine production of monocytes,but also regulates its proliferation,Ig isotype switching,and Ig synthesis of B cells.Furthermore,IL-13 synergizes with other hematopoietic growth factors in regulating proliferation and differentiation of primitive hematopoietic progenitor cells.

Abstract:BTF2,also named TFⅡH, with multiple subunit complex is believed to have helicase,DNA-dependent ATPase and phosphate kinase activities paticipated in transcription initiation and transcription-coulpled nucleotide-excision repair.During the formation of transcription initiation complex,polymerase ⅡC-terminal domain(CTD),TBP and associated transcription factors are phosphorylated by BTF2/TFⅡH in the presence of TFⅡE.These phosphorylation modifications can be expected to have effects on the regulation of transcription initiation through affecting protein-protein interactions. So BTF2/TFⅡH is an important transcription factor in eukaryotic cells.

Abstract:The initiation of translation is very important in the process of protein synthesis. On the major eukaryotic mRNAs template,initiation of translation is completed by a capdependent mechanism. Recent works demonstrate:a set of animal viruses mRNAs appear to have a different initiation mode based on a cap-independent internal initiation mechamsm.These mRNAs contain some conserved secondary structure in 5′untranslated region.Some specific protein factors can stimulate translation through the conserved site.

Abstract:The control of gene expression is a complex process and most studies on the regulation of the transcription were focus on the mechanisms of transcription activation. However,transcription repression is also an important factor in the regulation of gene expression.Recent studies have found that transcription of certain genes can be downregulated in two ways.First,nucleosome may pose an obstacle to form transcription complex. Second,a set of repressive molecules inhibit transcription in a gene-specific manner. These repressors are fallen into two classes: passive repressors decrease the activity of one or more positive transcription factors by competing for DNA binding sites or by reducing DNA binding activity of the positive factors. Active repressors，on the other hand，have intrinsic repressing activity and directly inhibit transcription initiation.

Abstract:Simple combinations of a few secondary structure elements with a specific geometric arrangement have been found to occur frequently in protein structures. These units have been called either supersecondary structure or motifs.Motifs are formed by packing side Chains from adjacent α helices or β strands close to each other. Simple motifs combine to form complex rnotifs. Several motifs usually combine to form compact globular structures,Which are called domains.In other words,the cores of domains are built up from combinations of small motifs，such as α-loop-α, α-loop-β, β-loop-α，β-loop-β or β-α-β motifs.

Abstract:The function of antisense oligonucleotide(ASON),to great extent,depends on its stability,bioavailability and binding or reaction ability to the targeting sequence.These physical and chemical properties can be changed via specific chernical,modification,and thus enhencing ASON′s antivirus,anticancer as well as other specific gene expression inhibition activities.

Abstract:As an important intracellular second messenger,cyclic GMP regulates various functions of cells,such as visual and olfactory signal transduction, vascular smooth muscle relaxation,lymphocyte activation and chemotaxis of reproductive cell.In different kinds of cells,cyclic GMP interacts with cGMp-dependent protein kinases,cGMp-regulated ion channels,cGMp-regulated cyclic nucleotide phosphodiesterases or ADP-ribosyl cyclase respectively.This means that cyclic GMP can regulate cell functions through protein phosphorylation or through pathways not directly related to protein phosphorylation. It appears that the regulatory mechanisms of cyclic GMP are variable and related to the specific subcelluar structure.

Abstract:The single cell gel electrophoresis (SCGE),also called comet assay,is a simple,sensitive,rapid and inexpensive detection technique of DNA breakage in individual mammalian cell.It has been used in both in vivo and in vitro studies to assess DNA damage and repair induced by various agents,such as physical factors,e.g. UV,radiation,chemical factors,e.g. oxidants, trichloro-ethylene, acrylamide,bleomycin,as well as ageing and smoking,in a variety of mammalian cell lines. A panorama of the development of the SCGE assay，the mechanism and the procedures of the method，and its potential applications in DNA damage and repair，biomonitoring，cancer therapy researches，etc. is given.

Abstract:Recent advances in the molecular characteristics,gene structure,functions of type X collagen and its relation to diseases were introduced.Type X collagen consists of three identified α peptides and is assigned to the non-fibril-forming collagen synthesized primarily by hypertrophic chondrocyte in growth plate cartilage.Complete type X collagen molecule includes COL,NC₁ and NC₂ domains in which COL domain,a main peptide,has two cleavage sites sensitive to collagenase. Short as is its chain, type X collagen displays a very stable property，and its melting temperature is up to 47℃. The gene of type X collagen，unlike other interstitial collagens，is composed of three exons and two introns，and the entire COL domain is encoded by a large exon-exon₃ which condenses the gene information. Type X collagen plays an important role during endochondral ossification and seems to be related to matrix degradation，mineralization and/or vascular invasion. Distribution and quantity abnormalities of type X collagen were observed in some osteoarticular disorders，such as osteoarthritis and rachitis. The mutations of type X collagen gene coding for NC₁ domain make the mutant polypeptides difficultly associate with each other，impair supramolecular assembles and lead to its disfunction in growth cartilage， which appears to elicit given inheritable chondrodysplasias.

Abstract:Cytoplasmic free Ca²⁺ and Mg²⁺ concentration(c (Ca²⁺)_i and c(Mg²⁺)_i) of alveolar macrophages in rabbit lung after incubation with sodium selenite were determined by SPEX AR-CM-MIC system.The results showed that high concentration sodium selenite(≥10^-4mol/L) had the cytotoxicity.The poisonous effect of selenite on macrophage led to the increase of c(Ca²⁺)_i and c(Mg²⁺)_i.High concentration selenite had some suppressive effect on the Ca²⁺-ATPase activity of erythrocyte membrane.

Abstract:Interleukin-1(IL-1)and opioid peptides,acting as neuromodulators,play roles in excitotoxicity of neurons.The interaction of IL-1,opioid peptides and imrnediate early genes c-fos and c-jun in rat corticocerebral cells was studied.The results showed that IL-1 βinduced transient and early c-fos and c-jun mRNA expression.The induction of c-fos and c-jun mRNA by IL-1 appeared within 15 min,was highest respectively. Addition to corticocerebal cells of antisense oligonucleotides to c-fos and c-jun, significantly in hibit the secretion of Leu-enkephalin and β-endorphin of antisense oligonucleotides to c-fos and c-jun appeared the dose response curve. These findings suggest that immediate early signals Fos and Jun partly regulate secretion of enkephalin and β-endorphin of corticocere bral cells induced by IL-1.

Abstract:It was found that the presence of an amino-space modifying thymidine in an oligonucleotide interfered the transfer reaction of [γ- ³²P] ATP bv T₄ polynucleotide kinase.When this modified thymidine located in the middle of oligonucleotide,50% activity of T₄ polynucleotide kinase was inhibited.When this modified thymidine located at the 5'-terminus,only 2% activity remained. Comparatively,those modifications did not affect the activity of T₄ RNA ligase.

Abstract:Two analogues of dioxobenzothiazole,2-chloro-5-dodecylmercapto-6-methyl-4,7-dioxobenzothiazole (2-C1-DMMDBT)and 2-chloro-5-butylamino-6-methyl-4,7-dioxobenzothiazole(2-Cl-BAMDBT), were synthesized.Their inhibitory properties on the enzymes of mitochondrial respiratory chain were studied in heart muscle preperation.Both of them show the inhibitory effect on the succinate oxidase, ubiquinol oxidase,NADH oxidase but not the cytochrome c oxidase.These results indicate that the inhibitory sites of both compounds are located on the area of ubiquinone reactions. The substitution of -SR and-NHR at 5-position of the benzothiazole ring makes the two compounds of 2-CI-DMMDBT and 2-Cl-BAMDBT show different behavior on the inhibition of NADH-Q reductase. The stronger inhibitory effect of 2-Cl-DMMDBT than 2-Cl-BAMDBT is probably due to the longer hydrophobic side chain of 2-Cl-DMMDBT，because the reactive sites of ubiquinone are all in the membrane of the mitochondria.

Abstract:The anoxia-reoxygenation model of cultured neonatal rats myocardial cells were developed, according to Laarse's method :anoxia and glucose deficiency for 60 min followed by reoxygenation and re-exposure to glucose for 30 min.The results showed that the intracellular malondialdehyde (MDA)content in the anoxia group was significantly increased,superoxides dismutase(SOD)activity was obviously reduced and membrane fluidity was decreased,all the changes were much more severe in the reoxygenation group.Total saponins of semen Ziziphi spinosae (ZS) could markedly and dose-dependently decrease MDA content，elevate SOD. activity and increase membrane fluidity. It proved the effects of ZS against lipid peroxidation induced by anoxia-reoxygenation.

Abstract:Human macrophage colony stimulating factor(hM-CSF) inclusion bodies expressed in E.coli were dissociated successfully by high intensity ultrasound in a suspension of 4mol/L urea instead of using 8 mol/L urea as solvent.The SDS-PAGE of suspension samples processed by ultrasound shows the same band at 17 000 as that solubilized by 8 mol/L urea.The results show the possibility of developing a new ultrasonic technique for the dissociation of inclusion bodies.

Abstract:A long arm biotin-p-nitrophenyl ester was synthesized using carbodiimidazole as condensing reagent,and 6-aminohexyl acid as linking arm.The chernical structure was established via spectroscopic,thin layer chromatographic as well as hybridization methods.The results showed that the long arm biotin-p-nitrophenyl ester was specific and the synthetic way was simple and efficient.

Abstract:Growth hormone releasing peptide (GHRP) was synthesized.It is an exogenous hormone promoting pituitary to release growth hormone.The amino acid sequence of GHRP is His-D-Trp-Ala-D-Phe-Lys-NH₂.The synthesis was carried out with SPPS and Boc strategy.The amino acid composition was found in agreement with its caculated values. The purity was 97.7%.The bioassays showed that it enhanced the growth of young mice significantly and this effect depends on the dosage of injection. GHRP is more sensitive to the younger mice.

Abstract:A simple and convenient method for the purification of neuron specific enolase (NSE)from human brain is described through only one DEAE-Sephadex A50 chromatography.The specific activity is 92.1U/mg and increase of purity 59.4 fold.Certain biophysical and biochemical features were also studied.The molecular weight of the subunit of NSE is 45 000 and pI is 4.7.Amino acid composition analysis showed that NSE is an acidic protein.

Abstract:A new biosensor for urea based on immobilized Corynebacterium glutamicum 629,coupling with potentiometric amrnonia gassensing electrode, was designed and constructed.The calibration plot of mV measurement vs. logarithmic urea concentration was linear in the range 1.1×10^-4～1.4 ×10^-2mol/L,with slope 51.2 mV/decade in pH 8.0,0.1 mol/L phosphate buffer at 30℃.The relationship between the initial response velocity and the substrate concentration was also discussed.The results indicate that the kinetic response process of the reaction catalyzed by bacterium is similar to one by isolated enzyme. By using Eadie-Hofstee plot,the apparent Michaelis-constant (K_m) and the maxium initial response velocity v_m for urease in the immobilized bacteria membrane were determined. The biosensor was relatively stable for 45 days.

Abstract:The distribution of Gc and Pi subtypes of 190 unrelated healthy donors in the Han population in Beijing were investigated by rapid and sensitive isoelectrofocusing. The running and developing time was half an hour each.Sample loading was 1.5μl Gc^1F is 0.4891,Gc^1S is 0.2432 ,Gc² is 0.2678. There is good agreement between the observed and the expected value (∑X²=1.404,0.7<P<0.8). Pi^M₁ is 0.7542, Pi^M₂ is 0.1808, Pi^M₃ is 0.0650. The agreement is good as well (∑X²=1.1233,0.7<P<0.8).

Abstract:The expression of FMR-1 homologous gene was investigated in rat brains from fetus to postnatal one month by Northern blot hybridization. The continuous transcripting during the whole stage and the higher expression level in late developing stage supported that FMR-1 gene plays an important role during the late CNS development in embryo.

Abstract:In situ hybridization is a necessary and hard work for screening cDNA library.Heated by microwave oven,bacteriophage lysis,DNA denaturation and fixation of DNA to filter occur in a single step;On the other hand,it is a really rapid procedure for analysis of the cDNA inserts of positive clones via polymerase chain reaction (PCR) amplification.