Abstract:Cytokines play an important role in the immune regulation.Among the different cytokines,there can be either synegy or suppression effects.Based on the network effects of the cytokines,researchers have designed and constructed by genetic engineering and protein engineering techniques some novel cytokines comprising dimeric cytokine proteins, which exhibited multiple bioactivities.Such molecules could be used for the researches on the immune regulation as well as the clinicla applications.

Abstract:von Willebrand factor(vWF) is a high molecular weight multimeric glycoprotein and is absent or abnormal in von Willebrand disease (vWD).The essential information for its function resides in the monomer. vWF participates in thrombosis and haemostasis through interacting with GPⅠb.GP Ⅱb-Ⅲ a,collagen,FⅧ and heparin.

Abstract:Myofilament arrangement,contractile proteins, and Ca²⁺-dependent regulatory mechanisms between the crustacean and vertebrate striated muscles are different. The ratios of the thick to thin myofilament of vertebrate striated, crustacean fast and slow muscles are 1:2,1:3 and 1:6 respectively, as well as the myofilament arrangement also differ from one another.The molecular assembly of the crustacean thick myofilament composes of myosin and paramyosin are differ from that of the vertebrate striated muscle.The thin myofilament comprises actin, tropomyosin, and troponin. The molecular weight of troponin T is relatively high, and troponin C has only single Ca²⁺-binding site. The thin and thick myofilament regulatory mechanisms coexist in the crustacean striated muscle.

Abstract:Actin widely occurs in plant cells as an important cytoskeleton element.It is involved in many key cellular activities. The structure, function and properties of plant actin are described here.

Abstract:The proteins which bound with lipid layers were named membrane proteins in biomem-brane.Because of the large hydrophobic surface in membrane proteins, and the amphiphilic (hydrophobic and hydrophilic) character,their purification and crystallization are very difficult.Introducing small molecular detergent and small amphiphil into crystallization system of membrane protein,a great progress have been made. So far,a few membrane proteins have been crystallized, among them only the reaction center of Rhodopseudomonas viridis and Rhodopseudomonas sphaeroides have produced crystals and been analysed with 3Å resolution. Two-dimensional crystal can be formed in a series of membrane proteins and the information of three-dimensional structure may be obtained by electronmicroscopy and image reconstruction.

Abstract:Platelet-activatng factor(PAF)is a potent phospholipid mediator.It is widely accepted that PAF effects through the reaction with its specific membrane receptors.PAF membrane receptor cDNA was cloned recently.The present paper reviewed developments on research concerning PAF receptor and its signal transduction.

Abstract:Eukaryotic mRNA 3'-untranslated regions' function are much complicated than it is thought. Recent studies showed that the 3'-untranslated regions determine not only-the stability of mRNA. but also time, location and products of translation of the mRNA.It is noteworthy that mutations within 3'-untranslated regions can lead to tumorigenesis.

Abstract:Lipid peroxidation may lead to base modification,DNA strand breaks and formation of various fluorescent products in model systems,bacteria and eucaryotic cells.and the selective destruction of the base guanine in DNA.The transient metal ions can intensify the DNA damage obviously.Antioxidants and free radical scavagers have the protective effect of varying degrees for DNA damage induced by lipid peroxidation.8-Hydroxyguanine,which is strongly implicated in mutagenesis and carcino-genesis. has been observed.The molecular mechanism of mutagenesis and carcinogenesis induced by lipid peroxidation aroused great concerns in the field of free radical biology.

Abstract:Apoptosis programmed cell death.is a natural form of cell death characterized by active Participated of a cell in the process leading to its own decrepit and death. Recently studies suggested that apoptosis is a result from a set of discrete cellular events that are regulated by a cascade gene expression.Oncogenes and tumor suppressor genes are involved in this regulation. Apoptosis is closely related to cancer.Failure and bolckage of apoptosis in tumor cells could therefore be the fundamental importance in contributing not only to the evasion of physiological countrols on cell numbers, but also to the resistance both to natural defenses and to clinical therapy.

Abstract:On the basis of analysis of TNF structure and the relationship between structure and function,a novel TNF coding sequence was synthesized by PCR technique and inserted into an expression plasmid. By temperature induction the transformed E. Coli with the novel TNF expression plasmid produced high yield of novel TNF, whose cytotoxic activity to L929 cell was 10³ higher than recombinant human TNF.

Abstract:A cosmid library,constructed from DNA of the γ-radiation-transformed REC: myc cell line, designated REC:myc:γ33.was transfected into NIH/3T3 cells,yielding foci.Another round transfection of DNA from the first round focus into fresh NIH/3T3 cells produced second round foci.An active N-ras gene which originated from rat REC: myc:γ33 cells was detected in the NIH/3T3 secondary transformants.With PCR and direct DNA sequencing techniques,rat N-ras gene was found activated in the REC:myc:γ33 cells by CAA→CGA point mutation at codon 61, but not in the REC:myc cells. Also rat N-ras gene was identified as a point mutated gene in the NIH/3T3 transformants, and the endogenous N-ras gene in the NIH/3T3 recipient cells remains normal. What was found to be more interesting is that five out of six γ-radiation transformed REC:myc cell lines bear the same point mutation (CAA→CGA) indicating association of γ-radiation-induced transformation with point mutation in the N-ras gene.

Abstract:Recombinant human Cu/Zn SOD(rhCu/Zn SOD) obtained from E.coli was covalently linked with an amphipathic molecule poly-(styrene-co-maleic acid) butyl ester (SMA) via amide linkage. When 42% free amino groups of the enzyme were modified. 88% remained enzyme activity was obtained.The results of circular dichroism of rhCu/Zn SOD and SMA-rhCu/Zn SOD indicated that the structure of the modified rhCu/Zn SOD was scarcely changed. Its biological half-life in blood was prolonged 22 times.and its abilities to resist pepsin and trypsin were increased significantly.

Abstract:An alkaline CMCase was partially purified from the culture medium of Bacillus sp.O74.The enzyme was purified 27.9 fold by sephadex G-100 gel filtration,ion-exchange chromatography and hydrophobic interaction chromatography.The enzyme was characterized by demonstration of optimum activity at 50℃ and pH 7.0.and its molecular weight of 52 500 determined by gel filtration.The pH range of the enzyme showing the activity is from pH 4 to 12,and at pH 9 and 10,it can keep 80% and 70% of the maximum.activity respectively.The enzyme was stable in the presence of the most metal ions, surface active agents and auxiliaries.

Abstract:Gene rearrangement analysis plays an increasing important role in the diagnosis of lymphomas. The possibility of detecting immunoglobulin heavy chain gene rearrangement in formalin-fixed, paraffin-embedded tissues was examined.30 cases of lymphoid lesions,only 11 have been extracted with high molecular DNA which could be used in southern blot, and others showed DNA degradation in some degree.The degraded DNA could also be used in antigen receptor gene analysis after amplified by polymerase chain reaction. DNA analysis using paraffin-embedded tissues has potential clinical and research applications in detecting gene abnormalities in rare-and difficult cases of lymphomas in which fresh specimen was not available.

Abstract:A series of DNA primers specific for human brain myelin basic protein (MBP) gene was designed and synthesized. MBP cDNA fragment about 600bp in length was amplified from human brain cDNA library by using polymerase chain reaction (PCR) with the specific primers P₁ and P₂. The recovered PCR product was flushed by klenow fragment and inserted into pGEM-3Zf (+) vector pretreated with SmaⅠand calf intestinal alkaline phophatase. The recombinant plasmid was used to trans-form competent cell JM 109. The positive colonies were directly screened on indicator plates. The recombinant plasmid DNA and insert fragment isolated from four positive colonies were analyzed by digestion with EcoR Ⅰ，Kpn Ⅰ and Taq Ⅰ.The different coding sequences including MBP exon Ⅰ—Ⅶ, Ⅰ—Ⅲ，Ⅲ—Ⅶ and Ⅰ—Ⅴ were amplified from these clones with their corresponding nested sets of primers respectively. These results show that these cDNA clones contain full-length coding sequence for 21.5kD human MBP.

Abstract:Proline isomerization catalyzed by peptidyl-prolyl cis-trans isomerase (PPI) in vivo is a limited procedure in protein folding. In order to study the catalyzing activity of PPI on the refolding of recombinant proteins in vitro,PPI is purified from pig kidney.and is investigated the effects of the enzyme on catalyzing the refolding process. Results indicate that PPI increases the folding rate without increasing the correct folding ratio and specific activity.and PPI has a high catalyzing activity even at very low concentration.

Abstract:The interaction between VIP and nucleotide was tested with advanced photo-affinity technique.It was found that VIP can bind radiolabled GTP specifically and this binding could be competitively inhibited by cold GTP(unlabled GTP).The experiment indicated that not only GTP could inhibit the binding between VIP and hot GTP, but also all other nucleoside triphophates such as ATP,TTP,UTP could competitively inhibit this binding,although their inhibitions were a little weaker than GTP.It means VIP binding nucleoside triphbsphate was a typical reversible binding reaction. It was found also that GDP, GMP at low concentration did not inhibit VIP binding hot GTP but enhanced the binding. Connecting with other researchers' results of GTP influencing on VIP-receptor interaction, it was considered that VIP could reversibly bind one of nucleoside triphosphates and this binding was modulated by the ratio of different nucleotides in reaction system. Through this binding, the interaction of VIP and it's receptor was regulated.

Abstract:Factors influencing the sensitivity, or the signal/noise ratio.of dissociation enhanced lanthaqide fluoroimmunoassay (DELFIA) have been studied. The fluorescence responses and signal/noise ratios for different europium amount were shown to be changed with the volume of enhancement solution.and there was an optimum volume at a certain europium amount.The smallest europium amount leads to the smallest optimum volume.20/00 of the net fluorescence intensity was increased by using tinfoil reflection layer. Effective washing and drying methods of microtitration strips decreased background fluorescence have been developed.

Abstract:Cuprozinc superoxide dismutase(CuZn-SOD) from human erythrocytes was purified by a procedure involving Cu²⁺ chelate affinity chromatography.It was shown in three experiments that the special chromatography held a number of important advantages for protein purification,such as a high rate of repeating performance and a large protein capacity. The purified enzyme,with a specific activity of 3073 U/mg protein, was tested for homogeneity by activity-stained and SDS gel electrophoresis.Accompanied by the study,a simple and efficient method was worked out for assessing the homogeneity of CuZn-SOD using its ratio of the absorbence at 260nm to that at 280nm.

Abstract:Isoenzyme 1 of lactate dehydrogenase (LD1) was measured by an immunoprecipitation method. The antibody to M subunit of LD was added to the patient’s serum and incubated for 5 min,at room temperature. The ratio of serum to antibody was 10:1.After incubation,a saturated ammonium sulphate solution was added with the same volume as serum. Then,centrifuged to precipitate all M-containing isoenzyme (LD2—LD5) as insoluble antigen-antibody complex. Determined the residual activity of LD in supernatant fluid. The relationship Between the LD activity and absorbance was linear up to 618U/L. Within-run coefficient of variation (CVs) of two samples were 3.8% and 4.7%.Day-to-day coefficient of variation (CVs) was 7.0%.The correlation of immunoprecipitation method and electrophoretic procedure were cinsistent (n=22, r=0.976).Reference values for total LD and LD1 were 102.3±16.4U/L and 23 .7±4.4U/L respectively. The ratio of LD1 to total LD was 23.1±3.9%.The advantages of immunoprecipitation method were:high specificity. good precision and linearity. easy operation. Immunoprecipitation method was very suitable for measuring LD1 and could adaptable to the automatic analyzer.

Abstract:Shorter running time,higher resolution, simpler operation without preparation of large amount of electrode buffer is the superior character of SDS PAGE semi-dry technique.It is more convenient with buffer soaked filter strips instead of electrode buffer with filter bridge or buffer gel strips.

Abstract:A new assay of protein kinase A using capillary electrophoresis has been established.It is a universal and useful method for kinase activity. The method based on principle that substrate (kemptide)and product (phosphorylated kemptide) are easily seperated by capillary electrophoresis and the enzyme activity can be calculated on the integrated area. A continous sampling technique which can analyse more than 10 samples in one run has also been developed.The new method is easy to operate and its accuracy and sensitivity are higher than that of conventional isotopic method.

Abstract:Digital Image Analysis is a new DNA content measuring method in cell nucleus. During the senile process of Tetrahymena pyriformis,change of DNA content in nucleus could be measured by this method. According to law of Beer-Larmbert,cell nucleus in different growth period showed change of nuclear DNA content using level of nuclear integral optical density.The method possess quick measuring speed, well repetition, simple operation and good results.The results showed:when Tetrahymena pyriformis began the logarithmic growth phase, the nuclear DNA content reached peak gradually. When cell ageing gradually, the times of cell division as well as DNA content would be gradually decreased.

Abstract:A X-Gal test paper method for detecting β-galactosidase has been developed.This method is based on the degradation of 5-bromo-4-chloro-3-indolyl-β-galactoside,a chromogenic substrate, into blue 5-bromo-4-chloro-indole by the reaction of β-galactosidase. Advantage of the method is that it not only consums X-gal less, but it is also more simple and convenient than the previous method.The present method is suitable for detecting a large number of the colonies containing gene encoding for β-galactosidase from an agar plate.

Abstract:Mammalian aspartate aminotransferases(AST·EC·2·6·1·1) exist in two predominant forms: one mitochondrial (AST-m) the other of cytosolic origin (AST-c). The electrophoretic migration rate of AST-c is between α-and β-glubulin. and the electrophoretic migration rate of AST-m is similar to γ-glubulin. The method of solid blue B dye with electrophoresis on agarose is not sensitive to AST-m. So the nitroblue tetrazolium (NBT) dye is used instead of the solid blue B dye.

Abstract:The intracellular free Ca²⁺ concentration ([Ca²⁺]_i) was measured in isolated neurocytes prepared from Sprague-Dawley rats with Fura-2 double-wavelength fluoremetry. The results showed that the [Ca²⁺]_i, of the resting neurocytes in Ca²⁺-containing solution was 109±12nmol/L(x±s, n=9).KCl (30mmol/L) markedly evoked [Ca²⁺] of the neurocytes (P＜0.01, n=9),and the rises of [Ca²⁺]_i by KCl is a concentration-dependent response.These results suggest that the adoption of Fura-2 double-wavelength fluoremetry in dissociated rat neurocytes in a useful and relatively easily applicable technique for monitoring intracellular Ca²⁺ changes.