Abstract:Enzymes are catalytically active not only in aqueous solution but also in organic media (low-water solvent system, reversed micelles, monophasic cosolvent system, and biphasic organic/aqueous system). Of special interest is the low-water solvent system, because it is important to organic synthesis. In this review,attention is focused on the factors that influence enzyme catalysis in a low-water solvent including the role of water, selection of the solvent and support, some special proterties acquired by enzymes in such a system are discussed. Examples of applications with the use of enzymes in organic synthesis,analysis, and polymer chemistry,are listed.

Abstract:Lectins are a kind of carbohydrate-binding proteins. Though they differ in their carbohydrate specificities, they resemble each other in many physicochemical properties. By now, a lot of plant lectins have been sequenced, and some of their three-dimensional structures have been established. A few lectin genes have been cloned. Comparison of their primary sequences and tertiary structures, we can find that plant lectins are several large groups of homologous proteins belonging to a superfamily.

Abstract:Fibronectin (Fn) is a high molecular dimer of glycoprotein with a series of discrete structural domains. It is composed of three type repeats,type Ⅰ,Ⅱand Ⅲ. A serial repeats form a functional domain. There is only one Fn gene in body, and by alternative splicing it produces many kinds of Fn polypeptides. which have different sequences in three variable regions.Fn is involved in a variety of biological functions. It is very important to elucidate the relationship between the function and structure relationship by deeply analysing the structures of its domains and gene.

Abstract:The α-sarcin domain of 285 rRNA is involved in protein synthesis reaction catalyzed by ribosomes. It was demonstrated that trichosanthin is an RNA N-glycosidase, and a new method for RNA N-glycosidase assay was preliminarily established. Trichosanthin cleaves the super-coiled double-stranded DNA to produce nicked circular and linear DNA, and other RNA N-glycosidases also have this endonucleolytic activity. The same molecular mechanism may exist in the action of trichosanthin on 28S rRNA. supercoiled DNA and HIV-1 RNA.

Abstract:This review summarizes the transcriptional regulations in the eucaryotic genes transcriped by three kinds of RNA polymerases. The regulatory strategies differ for higher eucaryotic cells with their huge DNA contents. First. much greater numbers of transcriptional factors are required. And second, these regulatory proteins simultaneously bind ot the nearby specific sites on DNA with proper orders. This demonstrated that the control of transcription in eucaryotic cells involves the interaction of protein factors with specific DNA sequence elements and the interactions between protein factors.

Abstract:Nuclear factors are increasingly important in playing part in regulating the expression of genes. Eukaryotic transcriptional initiation is controlled by complecated interactions between cis-acting DNA motifs and trans-acting proteins, which consist of nuclear factors. Four sequences involved in DNA sequence recognition have been determined as follows; zinc fingers : leucine-zippers; helix-turn-helix and helix-loop-helix motifs. Research from viral and animal systems turn to plant gene expression systems. Evidence has shown that the interaction of nuclear factors is the basis and pre-requisite for the regulation of gene expression.

Abstract:E.coli(Escherichia coli) has been widely used in expressing foreign genes, but different foreign genes may exhibit very different expression efficiencies. This article is the review of factors that influence expression of foreign genes in E.coli. and it will be helpful to know the information in this field, in order to take effective measures to improve expression efficiencies of foreign genes in E.coli.

Abstract:Antisense can be used to control the expression of specific genes. When targeted to specific messenger RNAs or specific sequences of the DNA double helix, antisense inhibit translation or transcription. Both strategies can beapplied to control the expression of oncogenes and growth factors in tumor cells. Here, the application of antisense was reviewed in cancer research briefly. a. Inhibition of oncogene and growth factor expression to suggest their function in tumor cells. b. Discrimination between proto-oncogene and activated oncogene. c. Problems and approaches in antisense gene therapy.

Abstract:Brown adipose tissue (BAT) is a kind of facultative-thermogenic organ, especially importantin small mammals.The key element in BAT heat production is the uncoupling protein (UCP), a unique protein located in the inner membrane of BAT mitochondria. Thermogenic stimulation of this tissue opens the UCP's proton channel, results in a proton short-circuit.thus bypasses the relatively small amount of ATP synthetase present in BAT mitochondria resulting in a severalfold accelerated oxidative metabolism. The structral and functional state of BAT is regulated by many factors, such as norepinephrine, thyroid hormone, insulin. pH, and food, enviormental temperature etc.

Abstract:Construction of complex antibody libraries that expressed soluble antibody fragments on the surface of fd-phagemid with high screening efficiency subjected to rounds of in vitro mutadons. The individual antibody gene can then be affinity matured by emulating the process that occurs in B-cells in vivo .The affinity matured antibody fragments are selected for their ability to bind antigen after phage recovery. This novel recombinant DNA methods may replace the technology of using mice and hybridoma for the selection and production of antibodies.

Abstract:The mentioned immobilized PH gradients isoelectrofocusing is a electrophoresis technique developed in 80' s. An approximate linear pH gradient is genarated by titrating weak acidic and basic acrviamide derivaties which then covalent bound into the polyacrylamide matrix. The pH gradient is stable and independent of electric field fluctuation. The present method provides higher resolution and larger loading capacity comparing with conventional carrier ampholyte isoeletrofocusing. It can analyse and purify protein with only minor pI difference.

Abstract:On analyzing the distribution and composition of element in single cell with scanning proton microprobe (SPM) and synchrotron radiation X-Ray fluoroscence microprobe (SR-XMF) it shows that zinc is a constituent of cell plasma. The levels of cellular zinc and iron were detectecd by above nuclear technique and the contents of MDA, SH group were estimated respectively by biochemical method for both normal and injured cell induced an peroxidation damage by hydroxyl-free radical. It was found that MDA content increased, SH group decreased. as well as Fe / Zn ratio raised during lipoperoxidation. By supplementation of zinc to culture medium. the inhibitory effect of zinc on lipoperoxidation was obvious from following experiment results that MDA content decreased. SH group content increased as well as Fe / Zn ratio reduced. The results suggest that zinc plays a role in maintaining the integrity of the cell and protects SH group of membrane protein thus preventing catalytic peroxidation reaction of iron.

Abstract:The role of lvsine residues in the structure and function of bacteriorhodopsin(bR) was studied by the chemical modification method──acetylation. After acetylation, the photoresponse signals and the decay of photocycle intermediate M412 were slowed down while the yields of M412 were decreased. But UV/VIS absorption spectra did not show that the conformation around retinal chromophore was disturbed by acetylation. The effect of acetylation was weakened by high pH or salt media. The results imply that lysine residues do not directly participate in the proton translocation. instead, they affect this process by their contribution to the surface protentials.

Abstract:Superoxide dismutase is modified with lauric acid to improve its stabillity. Activated lauric acid was reacted with bovine Cu, Zn-superoxide dismutase at 40℃ for 1h and it was further purified by a Sephacryl S-200 colum. There are 93% recovery of enzyme activity from the resulting lauric acid-superoxide dismutase conjugate. The specific activity of this enzyme product was 6000U / mg. The modified enzyme showed enhanced stability, substantially free from immunogenicity and prolonged its halflife in blood. As a consequence. it can beneficially be used as an enzyme for cosmetics and food industry.

Abstract:The phase-resolved photoacoustic spectroscopy has been used to analyse the pigmental distribution in intact plant leaves and has been compared with the photoacoustic phase spectrum of the leaves. The inverse correlation between the photoacoustic phase spectrum and absorption bands of chloroplasts has been observed. The characteristic valley exists in the photoacoustic phase spectrum of the leaf cuticle. In addition, there are some differences in the photoacoustic phase spectra obtained at different modulation frequency. The phenomena show that photoacoustic phase spectra can also be used for the nondestructive depth-profile analyses of biological sample as good as photoacoustic spectroscopy.

Abstract:Analysis of phenylthiocarbamyl (PTC) amino acids with ethanol as organic eluent is described. Compared with acetonitrile elution system, ethanol is less toxic, easier to obtain and much cheaper. Under optimized chromatographic conditions, the resolution, sensitivity and accuracy are excellent.

Abstract:A protocol by using 4 mol / L LiCl phasing the DNA and RNA could lead to simultaneous and rapid purification of total cytoplasmic RNA and genomic DNA from small numbers of transfected mammaliam cells. Comparing with other methods, this protocol shows rapid. easy and economic, and can be used in many aspects especially in the studies of mammalian cell gene expression and regulation.

Abstract:PCR direct sequencing is a method which combined PCR amplification with nucleic acid sequencing technique. According to this technique, direct sequencing DNA strand of PCR amplification using PCR primer, α-³⁵ S dATP and Taq DNA polymerase. The experiment showed that it is simple, rapid and stable. This method was used to analvze the tumor suppressor gene p53 mutation in human esophageal eancer. It was found that there were point mutation,insertion and deletion frameshift mutation of p53 gene in human esophageal cancer. Intron 5 and 8 sequences of p53 gene in human and Rhesus monkey were sequenced and in monkey they are 81 and 92 nucleotides respectively.

Abstract:EHMO studies of N₂ and C₂H₂ coordination-activation led to the conclusion that the iron-molybdenum cofactor of nitrogenase might be able to give a special treat to its special substrate, i. e. N≡N. The exogenous substrates except N₂ are apparently not to get into the cage of the active-center and / or to manoeuvre as freely as N≡N inside the cage with the proposed structural settings.

Abstract:The pH-dependent surface charge densities of the acetylated and the native purple membrane were determined by the ESR spin lable method. The spin probe is CAT₁₂. The number of surface charges shieded by acetylation was adapted as a criterion to calculate the surface charge numbers on both sides of the purple membrane from surface pH 4─11. The result shows that the total surface negative charge numbers are 9 per bacteriorhodopsin at surface pH 5─9 but increases both above surface pH 9 and below surface pH 5. It supports strongly the model based on five divalent cation binding sites on the surface of purple membrane.

Abstract:21 human primary brain gliomas and 11 human menigiomas were examined with RNA dot blot hybridization for the expression of p53, Rb and c-myc gene. It was found that the level of p53 gene expression is lower in 48.4% (15/31) of the tumors tested than that of normal brain tissues; the level of Rb gene expression is lower in 21.9% (7/32) for the tumors tested than that of normal tissues; and the level of c-myc gene expression is higher in 71.9% (23/32) for the tumors tested than that of normal tissues. Interestingly, in 13 of the tumors tested, the level of p53 gene expression is lower and the level of c-myc gene expression is higher. These results suggested that the expressive decrease of p53 gene and the expressive increase of c-myc gene are relative to the generation of human primary brain tumor.

Abstract:On the basis of the nature of nucleic acids and recent research achievements or findings about the macromolecuies, such as DNA-replication-repressor RNA, transcription-factor RNA,extracellular "communicator RNA ", ribozyme, gene shears, RNA editing, anti-virus and anti-tumor activities of antisense RNA, a new hypothesis, antisense RNA network, is advanced. i. e. There are many kinds of small antisense RNAs and their complementary antiantisense RNAs from genomic DNA within the organism. Because of self-modification (or other mechanism)，the antisense RNAs and the anti-antisense RNAs base-pair. but do not reanneal or hybridize with each other. This antiseuse RNA network, on the one hand, participates in regulating the expression of certain genes in particular tissues at particular time. keeps relative balance of various functional activitics. On the other hand, the network plays an important role in specifically recognizing and eliminating the nucleic acids mutated within the body or invaded into the body from the outside.