Abstract:ES cells are early embryo-derived multipotential cells that can be genetically manipulated in tissue culture. Thus genetic modification can be introduced into the gene pool by injecting transfected ES cells into blastocysts.The unique advantage that ES cells offer is thatthey can be screened in culture for rare geneticevents prior to germline transmission and the desired genetic mutant can be produced.Recently, genes which are involved in mousedevelopment can be identified using gene trap vectors in combination with ES cells. This new approach is very efficient for studying gene expression pattern during embryogenesis.

Abstract:Peptide growth factor receptors are membrane-bound glycopeptides that regulate the action of peptide growth factors on their target cells. Their peptide backbones could be divided into three segments: extracellular region, transmembrane region and intracellular region.According to the structural characteristics in these regions, especially the existence of protein kinase domain in the intracellular region, a new method of peptide growth factor receptors classification is postulated. The signal transduction pathways of these receptors are also compared.

Abstract:Ciliary neurotrophic factor (CNTF)is a trophic protein that promotes survival and/or differentiation of a variety of neuronal cell types including sensory, sympathetic, and motor neurons. CNTF receptor is a three-component complex, the α-subunit is not a transmembrane protein, but is anchored to the membrane via a glycosyl-phosphatidylinositol linkage. The other two components of the receptor complex which participate in the signal transduction are gp130 and LIFRβ. The three components of the receptor are assembled together stepwisely. In the intracellular signal transduction of the receptor, the Jak/Tyk family is involved.

Abstract:A DNA analogue was designed in a computer model by replacing the deoxyribose phosphate backbone in DNA with a peptide backbone. Its binding to the complementary oligonucleotide was observed with great specificity. PNA's synthesis, hybridization and its application in moleuclar biology etc. were reviewed.

Abstract:Membrane protein topology is the starting point for predicting the threedimensional structure. Many membrane protein topologies have been determined by using several experimental approaches such as chemical modification and fusion-protein approach. Studied on membrane translocation and insertion have determined two possible inserting structural elements.Statistical studies on membrane proteins with known topology and engineering membrane protein topology indicate a universal positive inside rule of helical-bundle proteins. Reliable strategies have been developed to predict the topology of membrane proteins, which is of great importance to reverse biology. But there is still a long way to go to make three-dimensional structure predictions.

Abstract:Paraoxonase can hydrolyzes paraoxon, the most highly toxic pesticide,and was paid good attention in recent decades, but there was no published report in our country. Its existence, substrate specificity, isolation, purification, polymorphism, genetic properties, relations with some diseases, and its protectionagainst organophosphorus compounds are introduced. It is beneficial for further studies of itsbiological properties, physiological function andapplication.

Abstract:In vitro genetics is a method for isolating and studying functional nucleic acid molecules in test-tubes based on their special phenotypes (e. g. binding properties, catalytic properties). In vitro genetic provides an effective, active method for determinating and artificial evolution of nucleic acid function sequences,so it was widely used in investigating the regulation of gene expression and biochemical reaction.The progress of in vitro genetic methods and applications in recent years is reviewed.

Abstract:p21 is a new discovered cell cycle control element, a CDK inhibitor. p15, p16,p27 are also CDK inhibitors. They can bind with cyclin-CDK complexes and inhibit their kinase activity. These CDK inhibitors play roles in G₁ restriction point and G₁/S checkpoint. Furthermore, p21 gene can be regulated by wild type p53. p21 plays a role in p53 mediated G₁ arrest which is induced by DNA damage. Expression of p21 gene is 10～20 times higher in senescence cells than in proliferating cells. It begins to express when muscle cells start differentiation. These results demonstrate that p21 plays a major role in cell proliferation, differentiation and senescence.

Abstract:A family of neurotrophic factors homologous to nerve growth factor (NGF) is designated by the name of neurotrophins. They play important roles in the differentiation and development of nervous system and might haveclinical potential in the treatment of neurodegenerative diseases. The recent advances in reciprocal but distinctive physiological roles of the neurotrophins and their expression regulation in brain are summarized.

Abstract:The mammalian zona pellucida plays a major role in the fertilization. The study of chemical substances in zona Pellucida and its bioactivities is of importance in studying the molecular mechanism of species-specific spermegg recognition and the induction of acrosome reaction. Studies in latest ten years show that zona pellucida mainly consists of glycoproteins which are synthesized inside oocyte and then tranferred to the outside of oocyte. Most animals have 4 or 5 kinds of ZPGPs, and of which proteins possess homologous. During the process of fertilization, ZPGPs are responsible for spermatozoa receptors and for the induction of acrosome reaction. ZPGPs contain N-linked and O-linked oligosaccharides, which are essential to the bioactivities of ZPGPs.

Abstract:Unicellular cyanobacterium metallothionein (MT-like) has been isolated and analyzed comparing with mammal MT. Although there are many differences on their amino acid composition, primary sequence and domain numbers of tertiary structure, their secondary structure and metal-binding properties are similar to each other, showing a kind of function-trending evolution. The MT-like gene: smt-locus has also been cloned and studied about smt A ORF structure, expressional regulation by metal inducing and smt B reverse-transcripted inhibiting, and about the mechanism of the smt genetic amplifi-cation and rearrangment as mammal MT genetic unit. Some questions and focal points about cyanobacterium MT-like studying are suggested.

Abstract:Serpin is a family of serine proteinase inhibitors homologous in structure and sequence,regulating many proteolysis cascade reactions.Their genetic aberrations in structure or secretion may result in substantial pathological problems. The clinical applications are based on their structures and mechanisms of inhibition.

Abstract:The clones of phage antibody (PhAb)to E．Coli J5 strain were enriched and screened by panning and filter blot with E．Coli J5 strain from a human antibody library. Four positive clones binding to E．Coli J5 strain were determined by ELISA. The results of inhibition test showed that the binding of positive clones to antigens could be respectively inhibited by E．Coli J5 strain, E．Coli Rc-LPS and anti-CGL MAbs to E．Coli J5 strain. PCR amplification showed that all of the four positive clones contained the expected heavy and light chain genes of human Fab fragment. SDS-PAGE and Western blot analysis confirmed that positive clones were able to express about 50 ku proteins after induced with IPTG.These data indicate that four positive clones express the human Fab fragment with antigen specificities.

Abstract:Chitosan was obtained from crab shells by treating with HCl and NaOH. The conditions of cellulase immobilized on chitosan by glutaraldehyde were studied. The results indicated that the immobilized-cellulase prepared by 0.1g dry chitosan cross-linking with 5% glutaraldhyde and then combining with 4.0 mg cellulase showed higher cellulase activity and better activity recoveries (75% ). And some characters of immobilized and native cellulases, such as optimum temperature Michaelis constant and the effect of ionic strength, stabilities to heat and repeat operation were studied and compared.

Abstract:A recombinant expression plasmid was constructed by inserting the cDNA encoding mature receptor-associated protein (RAP) into pGEX vector. High level intracellular expression of the RAP gene was Observed in the DH5a bacteria transformed with the recombinant pGEX vector after IPTG induction. The abundant GST fusion protein constituted 39. 4 % the total cellular protein. The fusion proteins were purified from bacterial lysates by using GST-Sepharose 4B affinity chromatography. The Western blot analysis showed that the rabbit anti-RAP antiserum recognized an apparent mass of 44 ku band from rat kidney microvillar protein. The high level expression and rapid purification of RAP-GST fusions was discussed.

Abstract:RNase TCS isolated from plant Trichosanthes Kirilowii Maxim has a highuracil-specific activity. In the absence of urea and under conditions of PH3.5, 50℃, it cleaves almost exclusively and uniformly at -NP ↓ U-. Inconjunction with RNase T1, U₂ and limited alkaline hydrolysis, the RNase TCS is useful in direct enzymatic RNA sequence analysis.

Abstract:Scavenging effects of total flavonoids of Astragalus (TFA), total saponins of Astragalus (TSA) and total polysaccharide of Astragalus (TPA) on superoxide anion radical and hydroxyl radical have been studied by ESR method. The results showed that all the three principles have stronger scavenging effect on superoxide anion radical than on hydroxyl radical. The intensity of scavenging effect of the three principles was TFA＞TSA＞TPA. It is suggested that the TFA and TSA are the main component in Astragalus mongholicus Bunge for protection against free radical damages.

Abstract:A study on character and content of antigen recognized by McAbGB₂ against serum antigen of human breast cancer was reported.The results demonstrated that the antigen recognized by McAbGB₂ is a complex protein which is composed of carbohydrate and protein and it is susceptible to heat. Competitive ELISA test showed that the binding of McAbGB₂ to its antigen could not be inhibited by ferritin and CEA. Western blot revealed that McAbGB₂ recognized antigen with molecular weight of 116 and 45 ku. The antigen recognized by McAbGB₂ exists in breast cancer tissue and serum. ELISA test with McAbGB₂ showed the rate of accord with positivity is 98 %(50/51) in breast cancer patient sera and the rates of false positivity are 6 % (3/50) in normal serum samples tend 6.7% (1/5)in benign breast disease sera respectively. The antigen recognized by McAbGB₂ may be a new tumor-associated antigen.

Abstract:To study the ultrasensitive enzymatically amplified time-resolved fluorescenceassay (TrF ) of bioactive matter, the experimental condition of trivalent terbium ion [Tb (Ⅲ) ], 5-fluorosalicyl phosphate ester (5-FSAP) and alkaline phosphatase (AP) have been investigated. It is found that there are some quantitative relationships between them. These results supply some good information for development of TrF.

Abstract:DNA molecular hybridization of chromosomal DNA among 15 strains of Brachybacterium were carried out by the method in which DNA labeled with nonradioactive photobiotin was binded to heat denatured single-stranded DNA in microdilution plates. Homology values among bacteria were obtained by measuring fluorescence intensity in the microdilution wells.The strains which is difficult to further classify at the species level with morphological, physiological and biochemical characteristics were determined their appropriate taxonomic positions on the basis of the genetic relatedness among microorganisms. This method is a rapid and accurate hybridization technique and plays diagnostic role on the taxonomic study of Brachybacterium.

Abstract:Reverse dot blot is featured by hybridization of labeled target DNA with immobilized probes. In conventional dot blot, each probe requires a separate hybridization, while in reverse dot blot all known allelic variants at several loci in a sample can be screened simultaneously. PCR was used to generate tandem polymers of ASO sequences for three β-thalassemia mutations [-28 (A→ G), CD17 (A→T) and CD41～42 (-TTCT) ], and then inserted the amplified probe polymers into plasmid. The final probes, which were amplified by PCR, were applied to the nylon membrane and hybridized with radioactive labeled HBB PCR products to detect the genotype of sample DNA.

Abstract:Foreign porcine growth hormone genes were introduced into Hubei white pigs. Inorder to avoid possible homology in metallothionein-Ia gene promoter between sheep and porcine, two PCR primers were designed and located on the regions of sheep metallothionein Ia gene promoter and porcine growth hormone gene, respectively. This reflects the exact results by PCR detection. The results of DNA blotting indicated that 6 of 43 offsprings showed positive integration.

Abstract:Rats running with an incrementalintensity to exhaustion were used as an experimental model to investigate the effect of acute exhaustive exercise on inner-mitochondrial membrane of skeletal muscler. It was found that, in exhausted rats, fluorescence polarization and membrane microviscosity of inner mitochondrial membrane increased significantly and the activities of NADH-CoQ reductase and ATPase in respiratory chain declined by 34.2% and 46.2 %,respectively. The result suggested that the functional alterations in mitochondrial membranes such as the changes on membrane dynamic and activities of respiratory chain enzyme may be one of membrane molecular characteristics for exercise induced fatigue.

Abstract:The sequence of a defined DNA primer can be detected easily by a method described as below. A PCR (polymerase chain reaction) was carried out with the primer to be detected and one of the M13 universal sequencing primers. The resulting PCR fragment was purified and inserted into a pUC-18 or pUC-19 at the multicloning sites. Then the sequence of the primer to be detected can be exactly known by sequencing the recombinated plasmid with a M13 universal sequencing primer.

Abstract:Direct evidence for the lack of intrinsic β-glucuronidase (GUS) gene in Agrobacterium tumefaciens LBA4404 was presented using PCR technique. No amplified fragment was obtained with a 21 bp primer pair, which is specific for the sequence of the GUS gene, from total cell DNA of the Agrobacterium tumefaciens LBA4404, whereas a single 1 .2 kb fragment, which is identical in size to that predicted for the internal GUS gene fragment,was amplified with the same primer pair from total cell DNA of the LBA4404 containing the plasmid pBI121 and from purified pBI121 respectively.