Abstract:Thrombopoietin (TPO) is a recently described novel cytokine produced in both liver and kidney. TPO protein secreted is glycoprotein with relative molecular mass of over 35 ku.Human and mouse mature TPO consist of 332 and 335 amino acid residues respectively. TPO receptor is related to c-Mpl which is a member of the hematopoietin receptor superfamily. TPO not only regulates the proliferation and differentiation of megakaryocyte progenitor cells, but also regulates the production of platelets.

Abstract:Nitric oxide synthase (NOS) is an important part of nitric oxide (NO) research in the fields of biology and medicine. In recent years, there is a rapid development in the researches of the nature and molecular characteristics of NOS, ever in some aspects of molecular genetics of NOS. Researches showed that to intervene in some processes of NOS-NO pathway, such as activation of the enzyme, synthesis, release and transportation of NO, and even genes related to encoding and expressing enzyme will provide new clues and methods for managing some clinic problems.

Abstract:The antisense RNA technique and its application in the areas of plant gene engineering were reviewed, including (1) ripening control of tomato and some other fruits; (2) plant resistance to diseases; (3) modification of flower colours; (4) control of starch synthesis in plants; (5) control of fatty acid synthesis in plant rapeseeds; (6) inducing male sterility or restoring male fertility in hybrid seed production; and (7) others, for example, reduction of lignin content in tobacco or trees, reduction of nicotine content in tobacco.

Abstract:It is prospective to use mammalian cells for producing fully active eukaryotic proteins. Vaccinia virus vector provides a simple, practical means for this purpose. As a vector, vaccinia virus has a number of useful characters: wide host range, non-carcinogenicity,permitting of cloning large fragments of foreign DNA (＞20 kb), retention of infectivity after insertion of foreign DNA, relatively high level of protein synthesis as well as "appropriate" transportation, secretion, processing and posttranslation modifications. In addition, the expressed proteins can prime immune system well to develope humoral and cellular immunity. Vaccine virus vector with high level expression will be or very useful in producing bioactive substances and constructing recombinant vaccines in mammalian cells.

Abstract:The newly developed techniques of peptide libraries have drawn great interest in ligands selection, and also have provided us numerous facts in the fields of molecular recognition. Basing on these results, two new opinions on molecular recognition between macromolecules have been reviewed. First, noncovalent bonds formed between a few residues of two bonded macromolecules may make a major contribution to the total energy of binding. Second, short peptides bearing these critical residues can mimic the interaction of large proteins. Thus, by studying specific interactions of short peptides, some details of interaction of proteins may be discovered, and also some theoretical and experimental bases to the design of peptide medicines and vaccines, that may promote the study of supramolecular systems.

Abstract:Poly (ADP-ribose ) Polymerase (PARP) is a kind of enzyme which responsible for posttranslation modification of proteins. It exists in many eukaryotic cells and catalyzes poly ADP-ribosylation of nuclear proteins including histone H₁ and itself. When cells are damaged by toxic agents that induce DNA breakages, PARP molecules will bind to DNA breakage and their catalytic activity is activated. Then they modify their acceptor protein and trigger a set of cascade reactions. Thus PARP is a possible molecular sensor and transducer to initiate the signal transferring path for reacting to damages of the cell. The information which they passed may decide the fate of a cell: repair or death.

Abstract:The development of antibody library has opened an effective way to produce human monoclonal antibodies. Although the antibody library technology came out only a few years ago, its selection system has been improved greatly, and now monoclonal antibodies with various uses can be screened from antibody libraries rapidly. This technology eliminates some limitations of traditional hybridoma methods. The development and future of antibody library was reviewed.

Abstract:There are about 100 000 different genes in higher organisms, and only 15% of them are expressed in any individual cell. Thus it is very important to isolate specific genes.Comparing with substractive hybridization, differential display is a more effective approach to isolate specifically expressed genes. In differential display, reverse transcripted products of mRNA are amplified and displayed on sequencing gel. Then differentially expressed genes are isolated. Although there are many difficulties in using this method, as further improved, it will be useful in various fields.

Abstract:A new approach for evoking an immune response: gene immunization becomes more and more interesting for many researchers.Gene immunization is to introduce purified plasmid DNA which contains protein coding sequences and the necessary expressing regulatory elements into certain tissues of animals, in order to evoke the immune response to the proteins coded by the plasmid. The basic methods,achievements and problems of this new field are described here.

Abstract:Programmed cell death (PCD)is different from ordinary death, necrosis. It is very important to determine which kind of death is PCD. The PCD detecting methods werereviewed in the following aspects: cell morphologic features, membrane integrity, DNA and other biochemical changes.

Abstract:Calponin is a smooth muscle-specific regulatory protein. The evidences of molecular cloning revealed the existence of 2 isoforms:α and β, composed of 292 and 252 residues respectively. Calponin binds to actin and inhibits actomyosin Mad²⁺-ATPase activity, thereby smooth muscle contraction. The actin-binding domain of calponin lies in 38 residues (145-182). Ser175 plays a critical role in the interaction of calponin with actin and the inhibition of the ATPase. It also binds to calmodulin in a Ca²⁺-dependent manner. The calmodulin-binding domain is between residue 52 and 144. Both binding and inhibition of the ATPase can be regulated by phosphorylation and dephosphorylation of calponin.

Abstract:After the elucidation of the threedimensional structure of Torpedo acetylcholinesterase by X-ray diffraction in 1991,studies by computer modelling and site-directed mutagenesis have led to significant progress in the elucidation of the structure-function relationship of this enzyme. And based upon this,efforts have been made to invcstigale further mechanism of inhibition by irreversible inhibilors (organophosphate), and that of the reactivation of the irreversiblly inhibited enzyme. In addition, progress in study of aging nirchanism of the inhibited enzyme was also reviewed.

Abstract:A lipid-depleted QH₂-cytochrome c reductase has been prepared by a column of calcium phosphate.The activity of this enzyme is lower and the cytochromes contained in this enzyme is partially (about 53 % of cytochrome b and 83 % of cytochrome c₁) reduced. The reconstitution of the lipid-depleted QH₂-cytochrome c reductase with lipids can not only recover the activity but also induce the reduced cytochromes retain to its oxidized state. This result indicates that a special interaction between the lipid and protein is important for keeping the enzyme in its native conformation.

Abstract:The m-hydroxybenzoate hydroxylase (MOB4-HOase) with 62 000 relative molecular mass from Comamonas testosteroni was purified to homogeneity upon SDS-PAGE by using sonic crushing, ammonium sulfate fractionation, molecular sieve chromatography, calcium phosphate gel chromatography and ion exchange chromatography. MOB4-HOase has been purified about 21 fold in specific activity with about 30% yield. This enzyme is a FAD-monooxygenase to catalyze m-hydroxybenzoate to protocatechuic acid.

Abstract:The pepsinogen with higher moleculer weight was purified from human gastric mucosa. The procedure included DEAE-52 ion-exchange chromatography and gel filtration HPLC. This 67 ku pepsinogen resists alkalinization up to pH 10.8. The optimal pH of the pepsinogen is 1.8 and its specific proteolytic activity is 5.96 U/mg.

Abstract:The protective effect of total flavonoids Astragalus (TFA), one of the natural anti-oxide agent isolated from Astragalus monghlious, on DNA strand breaks induced by the hydrogen peroxide and gamma rays has been investigated with the fluorometry assay of DNA unwinding (FADU). The results showed that the TFA has different degree of protective effect on DNA strand breaks caused by hydrogen peroxide and gamma rays respectively. It also showed some protective effect on DNA strand breaks induced by these two damage factors,when the concentration of TFA were 0.4 g/L and 0.6 g/L, respectively. When its concentra-lions were increased to 0.8 g/ L and 1.2 g/L, TFA could effectively protect DNA from hydrogen peroxide and gamma rays damages. Compared the protective effect of TFA on DNA strand breaks induced by hydrogen peroxide and gamma rays, the former was better. The protec-live mechanism of TFA on DNA strand break could be related to savenging free radicals.

Abstract:The cDNA encoding human manganese superoxide dismutase was amplified from the human liver total RNA by RT-PCR, ligated into pBV220. The cloned gene was analyzed by restriction enzymes EcoR l, Sal Ⅰ, and BamHⅠ. The sequence of the cloned gene was determined. hMnSOD was induced and expressed upon temperature shift from 32℃ to 42℃.Mn²⁺ supplementation in the bacterial growth media resulted in about 3-fold increasing of SOD activity. The special protein expressed accounts for 14% of the total protein of the bacteria.

Abstract:Metallothionein (rabbit liver)(MT),apo-MT, Zn₇-MT and Cd₇-MT were prepared respectively. The scavenging effects of Zn₇-MT and Cd₇-MT on hydroxyl radical were compared at various pH values, and at pH 6 the effects of Zn₇-MT were compared with related proteins and inorganic zinc salt. From these results it is concluded that the ability of Zn₇-MT to scavenge hydroxyl radical is far stronger than that of Cd₇MT and that the ability of MT to scavenge hydroxyl radical derives from reduced -SH group in MT.

Abstract:A simple method, the location staining method, for distinguishing different SOD types was introduced. Due to the different performances of the different types of SOD against inhibitors, .e. g. Cu, Zn-SOD band disappeared in the presence of H₂O₂ or CN^-, MnSOD disappeared in the presence of CHCl₃CH₃CH₂OH, and Fe-SOD lost in the presence of H₂O₂ or CHCl₃-CH₃CH₂OH on the electrophoresis gels, the gels after electrophoresis were treated with the different inhibitors and then stained. According to the loss or presence of these bands, different SOD types can be identified.

Abstract:Rapid semi-dry technique by filter strips shortens running time from 2～4h to 40～50 min without lowering resolution and using large amount of electrode buffer.It also simplifies operation and saves materials. Being compared with pH 8.9 anode PAGE, pH 4.8 PAGE has higher resolution in acid protein seperation.Very good results can be obtained by using pH 5.5 cathode PAGE with semi-dry technique by filter strips for alkaline sample separations.

Abstract:A subtractive hybridization system for isolating differentiation associated gene from human cancer cell line is developed. By using the strategy of differentiation-inducing in combina tion with cDNA-cDNA subtractive hybridization, a subtracted cDNA library from human lung adenocarcinoma cell line before and after treatment with all-trans retinoic acid(RA) was established. Three cDNAs response to RA treatment were obtained by screening of the subtracted cDNA library. The results of sequencing and function analysis show that three cDNAs are novel cDNAs of differentiation associated genes in human lung adenocarcinoma cell line. This system is also suitable for isolating cDNAs representing deleted or overexpressed gene in human cells.

Abstract:Enzymatic catalysis in organic solvent is one of the most interesting topics. Immobilized lipase from Mucor miehei catalysed esterification of organsilicon alcohol in organic solvent was explosed and the effect of various factors on the reaction was studied. The different organsilicon alcohol substrates and fatty acid substrates, organic solvent polarity and water contents etc. were studied.

Abstract:Type Ⅰ collagen was extracted from human embryonal bone by alternating acidic and neutral salt precipitation technique and was identified by SDS-PAGE, amino acid analysis and immunological method. The results showed that electrophoresis band of collagen extracted was the same as that of type Ⅰ collagen standard, ring precipitation test was positive, glycine was 1/3 in total of 1000 amino acid residues, the ratio of hydroxyproline and proline was 0.65. These suggested that the extracted collagen accord with the characteristics of type Ⅰ collagen and is highly purified. It could be used to prepare collagen products.

Abstract:The expression plasmid PCEA-TK or pCEA-CD was constructed by ligating the CEA gene promoter to suicide gene such as HSV-TK (herpes simplex virus thymidine kinase) gene or EC-CD (E. coli cytosine deaminase) gene. A human colorectal carcinoma cell line LoVo or a human uterine cervical cancer cell line HeLa was co-transfected with pSV2-neo and PCEA-TK (or PCEA-CD). After selection with G418, the transgenetic cell clones (hoVo/CEA-TK,LoVo/CEA-CD, HeLa/CEA-TK and HeLa/CEA-CD) were obtained. There was no significant difference in either morphology or cell growth curve between suicide gene transduced cells and wild type cells. But LoVo/CEA-TK (or LoVo/CEA-CD) cells were 2000(or 700) times more sensitive to the cytotoxicity of prodrug ganciclovir(or S-Fluorocytosine)than parental LoVo cells. However, HeLa/CEA-TK or HeLa/CEA-CD cells were still resistant to Ganciclovir (or 5-Fluorocytosine). These results showed the possibility of gene therapy for human colorectal carcinoma by cell type-specific expression of suicide genes.

Abstract:Human erythrocyte NADH-cytochrome b₅ reductase, or b₅ reductase, plays a major role in the reduction of methemoglobin,deficiency of which will lead to hereditary methemoglobinemia. Deterrnination of b₅ reductase activity is usually done by spectrophotometry. A new method has been developed for the qualitative and semi-quantitative detection of b₅ reductase activity, in which antibodies against b₅ reductase was dot-blotted onto nitrocellulosemembrane, and this in turn was used to capture and enrich b₅ reductase activity were visualized with the precipitable substrate MTT, or 3-(4, 5-dimethyl thiazolyl-2)-2, 5-diphenyl-tetrozolium bromide. Being straightforward and easy to follow, this method provides a new approach for the diagnosis of hereditary methemoglobinemia.

Abstract:A Chinese human genomic YAC (yeast artificial chromosome) library is being constructed with pJS97 and pJS98 as cloning vectors. An easier and more efficient protocol has been made successfully to protect the high molecular weight DNA from being degraded byusing polyamines solution and to remove smaller DNA by setting up a new method called "in situ electrophoretic size-fractionation". Furthermore, the glycerol at the final concentration of 20% is introduced directly into the medium used to grow the transformants, which would both simplify the operation and reduce the chance of contamination with other microorganisms or cross-contamination of YAC. clones. Such improved methods can be used in the construction and application of other genomic YAC libraries .