A CLONE OF HEPATITIS B VIRUS (SUBTYPE adr) DNA WITH A NEW HINDIII SITE

We have cloned the HBV genome subtype adr through its HindⅢ site into plasmid pBR.322. Twelve recombinant plasmids each with an insert of the HBV genome were obtained. The restriction map of one of the recombinants, plasmid pADR-H1, was analyzed. The location of the sites for BamHⅠ, BglⅠ, BglⅡ, SstⅡ, XbaⅠ and XhoⅠ in pADR-HⅠ were found to be the same as that in pADR-1, but the HindⅢ site of pADR-H1 is distinctly different from that of pADR-1. The BamHⅠ-HindⅢ fragment is 316 bp long in the gcnome of pADR-1. However, it is only 82 bp in pADR-Hl. No deletion of sequence between BamHⅠ and HindⅢ sites has been found in the HBV genome of pADR-H1, The sequencing data around the HindⅢ site of pADR-H1 in both pADR-H1 and pADR-1 show that there is a stretch of AAGTTT in pADR-1 compared to an AAGCTT in pADR-H1. In addition, other differences were found. There are three sites for AvaⅠ, four for HincⅡ, one for HpaⅠ and none for SphⅠ in the genome of pADR-H1 compared to four sites for AvaⅠ, three f     

CLONING AND SEQUENCE ANALYSIS OF 3''''-END REGION OF POTATO VIRUS Y GENOME

The entire coat protein (CP) gene and part of the 3'-noncoding sequence of the potatovirus Y (PVY, the Chinese isolate) genome were synthesized with polymerase chain reaction(PCR) using cDNA of its genomic RNA as a template. A restriction endonuclease site Ncoland the initiation codon AUG were included in primer Y5 while the SalI site was includedin primer Y3. After being double digested with Ncol and SalI enzymes, the PCR product wascloned into a pGEM derivative plasmid, and the CP gene in one of the clones, pPCY6, wassequenced. Several clones were selected from the cDNA library by using the CP gene frag-ment of pPCY6 as a probe and the sequences of these clones were determined. These se-quences included part of the NIb gene, entire CP gene and 3'-noncoding region, 1317 bp alltogether.Sequence analysis indicated that the nucleotide sequence homology of the CP geneof this strain with that of the 0 strain (94.2%) was a little higher than with that of the Nstrain (89.6%), but the homology of amino acid se     

Endonuclease-based Method for Detecting the Sequence Specific DNA Binding Protein on Double-stranded DNA Microarray

The double-stranded DNA (dsDNA) probe contains two different protein binding sites. One is for DNA- binding proteins to be detected and the other is for a DNA restriction enzyme. The two sites were arranged together with no base interval. The working principle of the capturing dsDNA probe is described as follows: the capturing probe can be cut with the DNA restriction enzyme (such as EcoR I) to cause a sticky terminal, if the probe is not bound with a target protein, and the sticky terminal can be extended and labeled with Cy3-dUTP by DNA polymerase. When the probe is bound with a target protein, the probe is not capable to be cut by the restriction enzyme because of space obstruction. The amount of the target DNA binding proteins can be measured according to the variations of fluorescent signals of the corresponding probes.     

TURNIP MOSAIC VIRUS COAT PROTEIN GENE: CLONING AND CONSTRUCTION OF THE PLANT VECTOR

Complementary DNAs to turnip mosaic virus (a radish Raphanus stativus isolate) genomicRNA were synthesized using oligo (dT) as primer and cloned into the vector λ-ZAP Ⅱ. Afterhybridization with a single-stranded cDNA probe and the sequencing of inserted DNA,positive clones with poly--A tails were obtained. One clone containing 1429-base pair insertwas sequenced. The coat protein gene was identified based on the molecular weight of theTuMV coat protein and the consensus sequences of the polyprotein processing sites ofpotyviruses. The 5' end of the coat protein gene was modified by PCR to introduce aninitiation codon, ATG, and two restriction enzyme sites. The gene was then manipulatedinto a binary vector pBIN437 which was derived from pBI121, and the plant expressionvector is being used to transform Brassica napus.     

STUDIES ON THE RNA POLYMERASES FROM THE CELL NUCLEI OF VICIA FABA L.LEAVES

Isolated cell nuclei from young leaves of Vicia faba L. have a high level of RNA polymorose activity and can serve as a good source for purification of higher plant RNA polymerases. The nuclei were lysed in a solution of high (NH_4)_2SO_4 concentration and the lysate was subjected to sonication to liberate RNA polymerases, which then were fractionated on DEAE-cellulose and DEAE-Sephadex columns. Three enzyme peaks were detected in the eluate fractions. According to their sensitivity to α-amanitin they are the RNA polymerases Ⅰ, Ⅱ and Ⅲ. Divalent cation Mn or Mg is essential for the enzyme activity. The Mn optimum concentration is 3mM and the Mg optimum concentration is 5mM for the RNA polymerases Ⅰ and Ⅱ. Calf thymus DNA and the DNA of Vicia faba have equal efficiency as template for RNA synthesis by these enzymes.     

CLONING AND RESTRICTION MAPPING OF HUMAN HBV GENOME SEROTYPE adr

A Bam HI cleaved 3.2 Kb fragment from the HBV adr genome was cloned in E. coli, using pBR322 as vector. sixteen restriction sites from the action of Bam HI, Hind Ⅲ, Bgl Ⅰ, Bgl Ⅱ, Ava Ⅰ, Hinc Ⅱ, Sph Ⅰ, Xba Ⅰ, Xho Ⅰ and Sst Ⅱ were determined and mapped. No cleavage sites were found for Eco RI, Pst Ⅰ, Sma Ⅰ, Hpa Ⅰ, Kpn Ⅰ, Pvu Ⅱ and Sst Ⅰ.The restriction map for HBV adr is significantly different from those reported for the subtypes adw, ayw and adyw.     

THE CLONED SALI FRAGMENTS OF Bombyx mori NUCLEAR POLYHEDROSIS VIRUS DNA

Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA has been cleaved with restriction endonuclease SalI into 29 fragments of different sizes. The range of the molecular weight of these fragments as detected by electrophoresis on agarose gel is from 0.70 Kb to 10.0Kb. 24 SalI fragments were cloned in plasmid pBR322. The sum of the molecular weight of cloned BmNPV DNA fragments accounts for about 80% of the virus genome DNA.     

IDENTIFICATION OF PARTIAL MUTATIONAL SITES IN HUMAN MITOCHONDRIAL DNA IN THE CHINESE AND ITS SIGNIFICANCE

A simple method for the identification of mutational sites in human mitochondrial DNA (mtDNA) was described. It was based on the human Cambridge sequence as a relative standard sequence and a single base pair substitution in mtDNA as a unique mutational form. The partial mutational sites can be determined using this method which was characterized by combining the restriction mapping with the analysis for the table of human mtDNA potential mutational sites with rapidity and simplicity. In the meanwhile, six mtDNA mutational sites found in Chinese population were identified by means of this method.     

COMPARISON OF THREE PROGNOSTIC EQUATIONS FOR PROBABILITY OF APPARITION OF STRIPE RUST OF WHEAT

Being used as a mathematical model of the latent period, a prognostic equation for probability of apparition, which is determined mainly by accumulated effective temperatures in the case of wheat stripe rust, is derived on the basis of experimental data.In field inoculation experiments of stripe rust on the susceptible wheat cultivar YD1817, the numbers of rusted leaves that were initiated by the infection that occurred on the i-th day and were just erupting into uredium pustules on the j-th day were observed every day. In the plots with accumulated effective temperatures as abscissa and with accumulated probability of apparition as ordinate, distribution of relevant points for the observed results from 14 experiments follows an S-shaped curve. Among the three models, namely, the Weibull function, logistic model, and Sine-square model, the logistic model seems to be the most fitted one with the determining equation: where PP_i is the accumulated probability of apparition on i-th day and TT_i is the accu     

ORGANIZATION OF NUCLEOSKELETON AND ITS RELATION TO DNA TOPOLOGICAL ORGANIZATION

The organization of nucleoskeleton fibers and its relation to DNA organization in the interphase micronucleus of a ciliate (Stylonychia mytilus Muller) were investigated mainly by the macromolecular spreading procedure combined with electron microscopy. It was shown that the nucleoskeleton fibers are organized as a regular organization termed the nucleoskeleton subunit which is composed of a structural center and a number of branch-like fibers extending radiately from the center. The whole micronuclear skeletal network is composed of a number of the essential subunits which are connected with each other. The micronuclear DNA is closely associated with the nucleoskeleton subunit and constructed as highly ordered DNA loops which appear in some different forms of topological organization. After the DNA-rich nucleoskeleton is digested with proteinase K, the nucleoskeleton subunit disappears, while the DNA loses its regular organization and becomes very random and loose, which Suggests that the nucleoskeleto     

THE NUCLEOTIDE SEQUENCE OF SURFACE ANTIGEN GENE OF HEPATITIS B VIRUS SUBTYPE adr

The nucleotide sequence of the XhoI-BamHI fragment (1279bp), which contains the sur-face antigen gene (S gene) of HBVadr, was determined by Maxam and Gilbert's method.By comparing the differences both of the nuclectide sequence in the S gene and its codedamino acid sequence between adr and those reported for adw, ayw and adyw, some new var-iation sites were discovered. The differences were mainly distributed in the two hydrophilieregions. However, at those sites which might show biological function, there were no varia-tions among different subtypes, they are relatively conservative in heredity and evolution.Comparing the variation of the nucleotide sequence in the S gene region with that in thenon-S gene region, it is shown that the frequency of variation in the non-S gene regiondoubled that in the S gene region. Tim S gene region is more conservative.     

CYTOCHEMICAL STUDY OF ELECTRON MICROSCOPY ON FRUCTOSE 1,6-DIPHOSPHATASE AND URIDINE DIPHOSPHOGLUCOSE PYROPHOS PHORYLASE IN THE MESO PHYLL CELLS OF Stevia rebaudiana BERTONI

The subcellular localizations of fructose 1,6-diphosphatase (FDPase, EC 3.1.3.11) and uridine diphos-phoglucose pyrophosphorylase (UDPG PPlase, UTP:α-D-glucose-I-phosphate uridylytransferase, EC 2.7.7.9) in the mesophyll cells of a new sweetener plant (Stevia rebaudiana Bertoni), both of which arecritical in carbohydrate metabolism, were determined and the activities of both enzymes in the leaves ofdifferent ages were compared in this study. This experiment reveals: FDPase is a membrane-bound enzymeand is specifically localized on the thylakoid membranes of chloroplasts and the plasmic membranes.FDPase is only found on the thylakoid membranes of chloroplasts in the young mesophyll cells, while it isfound on both the thylakoid membranes of chloroplasts and the plasmic membranes in the mature meso-phyll cells. UDPG PPlase is distributed in the cytoplasmic matrix freely, and is localized on Golgi flat-tened sacs and Colgi vesicles in a membrane-bound form. In this study, it is suggested that the chloropla     

Surface structure and reaction performances of highly dispersed and supported bimetallic catalysts

Surface structures of Pt-Sn and Pt-Fe bimetallic catalysts have been investigated by means of Mssbauer spectroscopy, Pt-L_Ⅲ-edge EXAFS and H_2-adsorption. The results showed that the second component, such as Sn or Fe, remained in the oxidative state and dispersed on the γ-Al_2O_3 surface after reduction, while Pt was completely reduced to the metallic state and dispersed on either the metal oxide surface or the γ-Al_2O_3 surface. By correlating the distribution of Pt species on different surfaces with the reaction and adsorption performances, it is proposed that two kinds of active Pt species existed on the surfaces of both catalysts, named M_1 sites and M_2 sites. M_1 sites are the sites in which Pt directly anchored on the γ-Al_2O_3 surface, while M_2 sites are those in which Pt anchored on the metal oxide surface. M_1 sites are favorable for low temperature H_2 adsorption, and responsible for the hydrogenolysis reaction and carbon deposition, while M_2 sites which adsorb more H_2 at higher tem     

A Streptomyces PLASMID pHZ65 AND ITS DEVELOPMENT INTO CLONING VECTORS

FR--0001 and FR--005 are two fusants obtained through protoplast fusion between differ-ently marked derivatives of Streptomyces hygroscopicus 5102, which produce three agricul-turally important antibiotics. Although they show distinct differences in morphologicaland cultural characteristics, antimicrobial activity and metabolites, they all carry a 20.1 kbplasmid (pHZ65) with complete DNA homology. A detailed restriction map with 29 sitesfor restriction enzymes BamHI, BclI, EcoRV, KpnI, PstI, SphI, SstI and XhoI has been deter-mined. Four Strepiomyces-E. coli bifunctional plasmids, pHZ200, pHZ201, pHZ206 andpHZ207, have been constructed by the in vitro insertion of an E. coli plasmid pIJ2703 whichcarries the tsr gene (expressible in Streptomyces) and amp gene (expressible in E. coli)into the BclI or BglII sites of pHZ65. The replicability of a series of plasmids obtainedby the cloning of DNA fragments from pHZ65 into the BclI site of pIJ2703 in S. lividansshows that the essential replication region of pH     

Syntheses,Crystal Structures and DNA-binding Properties of Zn(Ⅱ), Ni(Ⅱ) and Co(Ⅱ) Compounds Containing Thiazole Derivatives

Zn(Ⅱ), Ni(Ⅱ) and Co(Ⅱ) compounds(1～3) based on 2-(2-pyridyl)benzothiazole(bpt) and terephthalic acid(PTA) were synthesized. The crystal structures of [Zn(bpt)(PTA)2](1), [Ni(bpt)(PTA)2](2), and [Co(bpt)(PTA)2](3) have been determined by single-crystal X-ray diffraction analysis, which shows that all the three complexes belong to monoclinic system with space group P21/c. Time-dependent density functional theory(TD-DFT) calculation is performed on a reference structure of compound 3. The excited electrons mainly localized at the π* of ligand 2-(2-pyridyl)benzothiazole, which will be convenient for them to bind with the DNA reacting sites. Fluorescence spectroscopy, ultraviolet(UV) spectroscopy and viscosity were used to characterize the interaction of the compounds with Calf thymus DNA(CT-DNA). The results indicate that compounds 1～3 bind to CT-DNA and have a strong interaction with DNA. The compounds can probably bind to CT-DNA via a non-intercalative mode as concluded by studying the viscosity of a DNA solution in the presence of the compounds. This combination can effectively break DNA, which speculates that these three compounds may interact with the cancer cell DNA in this binding mode, thereby damaging the cancer cells.     

PROPERTIES AND THERMODYNAMICS OF ADSORPTION OF BENZOIC ACID ONTO XAD-4 AND A WATER-COMPATIBLE HYPERCROSSLINKED ADSORBENT

The adsorption behavior of benzoic acid onto a water-compatible hypercrosslinked polymeric adsorbent NJ-8 wascompared with that onto macroporous Amberlite XAN-4. This paper focuses on the static equilibrium adsorption behaviors,the adsorption thermodynamics and the column dynamic adsorption profiles. Five isotherm models are used to fit the results.This shows that the Freundlich equation can give a perfect fit. The specific surface area of NJ-8 is about as high as that ofAmberlite XAD-4, but the adsorbing capacity for benzoic acid on NJ-8 is about 14.9%-64.8% higher than that on AmberliteXAD-4, which is attributed to its microporous mechanism and partial polarity. The negative values of the adsorptionenthalpy are indicative of an exothermic process. Both enthalpy and free energy changes of adsorption manifest a physicalsorption process. The negative values of the adsorption entropy indicate that adsorption is well consistent with the restrictedmobilities and the configurations of the adsorbed molecules on the surface of the studied adsorbents with superficialheterogeneity. Both adsorbents were used in mini-column experiments to demonstrate the higher breakthrough adsorbing capacity of the hypercrosslinked polymeric adsorbent NJ-8 to benzoic acid, as compared with that of Amberlite XAD-4.     

THE ORIENTATION AND CRYSTALLIZATION OF POLYETHYLENE TEREPHTHALATE

The drawing behavior of three types of PET spherulites and PET amorphous samples have beenstudied. Two different sample preparation techniques were used in this study: (1) The films withnormal positive, normal negative or abnormal spherulites were prepared by solution casting tech-niques, then the films were deformed by uniaxial drawing. The uniaxial drawing behavior of PETspherulites appears to be dependent on the angles between the c-axis and the radius direction of thespherulites and that the deformation of spherulites becomes more difficult the larger the angles. (2)Amorphous films of PET were prepared first, then the films were deformed under uniaxial drawingto achieve c-axis orientation at a temperature near the glass transition temperature. The orientedfilms were subsequently annealed with fixed length at 215℃The films prepared in this way ex-hibit excellent c-axis orientation along the stretching direction. The degree of perfection of thecrystalline structure is much greater than that of the spherulites.     

TRANSFER OF RADIATION-INDUCED SPINS FROM DEOXYRIBONUCLEIC AND TH

When calf thymus deoxyribonucleic acid (DNA), propyl gallate (PG) and their five mo-ecular mixtures (with PG content of 1, 2, 5, 10 and 20%) are irradiated with γ-rays indry state in vacuum at 296°K, the ESR spectra of all molecular mixtures differ strikinglyfrom those of DNA, but bear a close resemblance to those of PG. The spin yield in the PGcontained in these mixtures is two to three orders of magnitude higher than that in the caseof PG irradiated separately. Furthermore, on the basis of the relative saturation characteris-tics of ESR spectra, these molecular mixtures behave more like PG than like DNA. It maybe inferred that the radiation-induced spins could be transferred from DNA to PG. Withr representing the molar ratio of nucleotides to PG, we have found a good linear correlationbetween the transfer ratio (TR) and r~(1/2). One PG molecule could protect at least 68 nu-eleotides in the duplex DNA chain, and thereby the minimal range of spin transfer is estimat-ed at 115 ?. Results obtained from irradiation at 77°K show that PG exerts no protectiveeffect on DNA, so DNA sustains an irreversible damage. It is thought that the spin transferfrom DNA to PG is exclusively due to a hydrogen transfer mechanism. We have also demons-trated the transfer of radiation-induced spins from both thermally denatured DNA and TMPto PG. The former process can be ascribed primarily to the hydrogen transfer mechanism,Whereas the latter, as in the case of native DNA, exclusively to this mechanism.     

EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTER DISTRIBUTION OF SUPPORTED ZIEGLER-NATTA CATALYST

The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesized by MgCl_2/DIBP/TiCl_4 (DIBP: diisobutyl phthalate) weredetermined by fractionating the copolymers according to crystallinity and characterizingthe fractions by ~(13)CNMR. The effects of two alkoxysilane donors, triethoxyphenylsilane(PTES) and dimethoxydi-tert-butylsilane (TBMS), on CD and ID of the copolymrs werecompared. Three main parts in the CD diagram of each copolymer were distinguished,which were correlated to active center distribution (ACD) based on three groupe of dif-ferent active centers. By studying the changes in 1-hexene content, microisotacticity andreactivity ratio product of three typical fractions, the effects of external donor on ACDwere better elucidated. It was found that TBMS shows much stronger effects on ACD thanPTES. In the former system, most fractions were produced on active centers with relativelylower r_1r_2, higher reactivity to 1-hexene, and higher stereospecificity as compared to thesystem without external donor. It is concluded that the observed very extensive changesin ACD are mainly resulted by the formation of new types of active centers, possibly bycoordination of external donor to certain positions on the catalyst.     

Investigation of the Interaction between Isoflavonoids and Bovine Serum Albumin by Fluorescence Spectroscopy

The interactions of bovine serum albumin （BSA） with three structurally related isoflavonoids, genistein, puerarin and daidzein, were studied under physiological conditions by fluorescence spectroscopic technique. The quenching mechanism of these compounds with BSA was suggested as static quenching and the binding constants were determined at different temperatures based on the fluorescence quenching results. The transfer efficiency of energy and distance between the acceptor and BSA were investigated on the basis of the mechanism of the Forster energy transference. According to the thermodynamic parameters it has been suggested that the acting force be mainly hydrophobic force. The comparison of binding potency of the three isoflavonoids to BSA showed that the substitution by 5-OH and 8-Glc could enhance the binding affinity. All these obtained in the work can make us better understand the mode of the action and pharmacological activities of the isoflavonoids.