博莱霉素与DNA的作用机理及其类酶性研究

详细介绍了博莱霉素（ＢＬＭ）与ＤＮＡ的结合作用、活化ＢＬＭ与各种自由基在ＢＬＭ介导的ＤＮＡ断链反应中的作用以及ＢＬＭ类似酶的催化行为等多方面的研究进展情况．

博莱霉素A_5的类酶性研究

研究了博莱霉素Ａ５（ＢＬＭＡ５）与ＤＮＡ作用前后的光谱性质及初步的动力学性质，发现ＢＬＭＡ５可催化ＤＮＡ氧化断链，而且符合米氏动力学．通过对ＢＬＭＡ５的催化效率、底物专一性以及温度、ｐＨ、金属离子对ＢＬＭＡ５催化ＤＮＡ断链反应影响的研究，发现ＢＬＭＡ５的作用行为在许多方面与酶的催化行为非常类似，提出ＢＬＭＡ５是一种小分子生物催化剂的看法．

RICE TRANSFORMATION WITH A PHYTOALEXIN GENE AND BIOASSAY OF THE TRANSGENIC PLANTS

Immature embryos, mature embryos and embryogenic calli of 6 rice (Oryza sativa L.) materials were transformed with particle bombardment. The plasmids pSSVstl and pVE5+ were used, both containing the phytoalexin gene from grapevine coding for stilbene synthase, but driven by 35S and its own promoter respectively. Through resistance selection for G418 (100 to 150 mg/L) or hygromycin (50 mg/L), 54 independent transgenic plants were isolated and further assessed by PCR, Southern blot and Dot blot analyses. The transgenic plants and their progenies were tested for resistance to blast ( Pyricularia oryzae ) and bacterial blight of rice ( Xanthomonas oryzae ). Preliminary results indicated that the stilbene synthase gene could enhance the resistance of transgenic plants and their progenies to both pathogens.

Differences in Phenolic Compounds and Related Enzyme Activities between 2 Eucalyptus Species

[Objective] The aim was to provide theoretical basis for speeding up the popularization of Eucalyptus dunnii.[Method] Differences in phenolic compounds and related enzyme activities between hard rooting E.dunnii and easily rooting E.urophylla×E.grandis clone （U9） were studied.[Result] There were significant differences in contents of phenolic compounds and activities of indole acetic acid oxidase （IAAO）,andperoxidase （POD） and polyphenol oxidase （PPO） between the two Eucalyptus species.Compared with U9,contents of phenolic compounds and POD activity of E.dunnii cuttings were relatively high,while activities of IAAO and PPO were relatively low.[Conclusion] More phenolic compounds and the differences in related enzyme activities might be the major factors to result in hard rooting of E.dunnii cuttings.

Variation of Enzyme Activity in Flue-cured Tobacco-growing Soil Planted with Different Lastseason Crops

The rice soil （last crop was rice） and arid red soil （last crop was corn） were used as a test material for the pot experiment. The variation of enzyme activi-ty in flue-cured tobacco-growing soil planted with different last-season crops was in-vestigated at different growth stages in this study. The results showed the activity variation of the 3 enzymes differed in the 2 soils at different growth stages. The catalase activity in the arid red soil trended to decrease overal from the vigorous growing stage to harvesting stage; while it decreased gradual y in the rice soil until the harvesting stage. The phosphatase activity in the 2 soils al increased with the proceeding of growth period. The urease activity in the arid red soil decreased gradual y at different growth stages, but the variation of urease activity in rice soil was irregular. During the growth of flue-cured tobacco, the catalase and urease ac-tivity in the arid red soil increased first and then decreased, and the phosphatase activity increased gradual y. ln rice soil, the catalase activity increased first and then decreased; the phosphatase activity decreased first and then increased; the urease activity increased first, then decreased and increased last. The activity of al the en-zymes in the 2 soils showed significant differences compared to the control except some enzymes at the vigorous growing stage. lt was suggested the planting of flue-cured tobacco would affect greatly the soil enzyme activities.

Effect of Magnetic Field on Enzyme Activities in Main Soils of Northeast China

Soil enzyme activities as affected by applied magnetic field were studied with three main soils (brown soil, black soil and albic soil) collected from Northeast China. Appropriate intensities of magnetic field could obviously enhance the activities of hydrogen peroxidases, invertases, amylases and phosphatases in the three soils, although the effect varied with types and water regimes of the soils. Increasing times of magnetic treatment could multiple its good effect on the activities of hydrogen peroxidases in soils.

Cloning, overexpression, and characterization of a novel organic solvent-tolerant lipase from Paenibacillus pasadenensis CS0611

We found a novel lipase gene in the Paenibacillus pasadenensis CS0611 strain.The lipase gene sequence was cloned into the pET-28a expression vector to construct a recombinant lipase protein containing 6×His tags at the C-and N-termini,respectively.High-level expression of the lipase in E.coli BL21(DE3)was obtained upon induction with IPTG at 20°C.The recombinant lipase activity was approximately 1631-fold higher than the wild type.His-tagged recombinant lipase was purified rapidly and efficiently by using Ni-charged affinity chromatography with 63.5%recovery and a purification factor of 10.78.The purified lipase was stable in a broad range of temperatures and pH values,with the optimal temperature and pH being 50°C and 7.0,respectively.Its activity was stimulated to different degrees in the presence of metal ions such as Ca2+,Mg2+,and some non-ionic surfactants.In addition,the purified lipase was activated by a series of water-miscible organic solvents such as some short carbon chain alcohols and was highly tolerant to some water-immiscible organic solvents.

Purification and characterization of alkaline chitinase from Paenibacillus pasadenensis CS0611

An extracellular chitinase produced by Paenibacillus pasadenensis CS0611was purified by ammoniumsulfate precipitation,HiTrap DEAE FF and HiLoad26/600Superdex200pg column chromatography.The apparent molecular mass determined by sodium dodecyl sulfate polyacrylamide gelelectrophoresis was69kDa.The optimum pH and optimum temperature of the chitinase were5.0and50°C,respectively.The enzyme showed high stability at alkaline pH values and temperaturesbelow40°C.Additionally,the metal ions Mn2+,Mg2+,and Co2+inhibited activity of the chitinase.Thechitinase was active on colloidal chitin with an apparent Km of4.41mg/mL and Vmax of1.08mg/min.Substrate spectrum analysis indicated that the chitinase reacted preferentially with the glucosidicbond between GlcNAc‐GlcNAc.The enzymatic hydrolysate was analyzed by high‐performance liquidchromatography and thin layer chromatography,and clearly showed that a subunit of(GlcNAc)2was the main hydrolysis product.

Assessment of Ecotoxicity of Topsoils from a Wood Treatment Site

A series of 9 soil samples were taken at a timber treatment site in SW France where Cu sulphate and chromated copper arsenate （CCA） have been used as wood preservatives （Sites P1 to P9） and one soil sample was collected at an adjacent site on the same soil type （Site P10）. Copper was a major contaminant in all topsoils, varying from 65 （Soil P5） to 2600 mg Cu kg^-1 （Soil P7）, exceeding background values for French sandy soils. As and Cr did not accumulate in soil, except at Site P8 （52 mg As kg^-1 and 87 mg Cr kg^-1） where CCA-treated posts were stacked. Soil ecotoxicity was assessed with bioassays using radish, lettuce, slug Arion rufus L., and earthworm Dendrobaena octaedra （Savigny）. There were significantly differences in lettuce germination rate, lettuce leaf yield, radish root and leaf yields, slug herbivory, and earthworm avoidance. An additional bioassay showed higher negative impacts on bean shoot and root yields, Rhizobium nodule counts on Bean roots, and guaiacol peroxidase activity in primary Bean leaves for soil from Site PT, with and without fertilisation, than for soil from Site P10, despite both soils having a similar value for computed free ion Cu2＋ activity in the soil solution （pCu^2＋）. Beans grown in soil from Site P7 that had been fertilised showed elevated foliar Cu content and phytotoxic symptoms. Soils from Sites P7 （treatment plant） and P6 （storage of treated utility poles） had the highest ecotoxicity, whereas soil from Site P10 （high organic matter content and cation exchange capacity） had the lowest. Except at Site P10, the soil factor pCu^2＋ computed with soil pH and total soil Cu could be used to predict soil ecotoxicity.

Inhibition of Acrosomal Enzymes by Gossypol Is Related to Its Antifertility Action

To investigate into the mechanisms underlying the irreversible sterility induced by gossypol, we studied the relationship between its inhibitory action on acrosomal enzymes and its antifertility effect.As shown by our result, after exposure to gossypol (l.25-60 μg/ml) for 15 min. in vitro,the sperms' ability to penetrate bovine cervical mucus and the fertility rate were significantly reduced. Also, following administration of gossypol (12.5 mg/kg/day) for six weeks, the rate of fertilization in vitro by hamster sperm was significantly decreased. In the gossypol-treated group, extracts of testis sperm delayed dispersion of cumulus cells, suggesting inhibition of hyaluronidase and other acrosomal enzymes. Furthermore, the acrosin and arylsulfatase activities were shown to be markedly inhibited. Thus, a parallelism was displayed between the reduction of fertility and the decreasc in acrosin and arylsulfatase activities in epididymis sperms.Besides, the inhibition was reversible and was dosage-and durationdependent. In conclusion, the assay of acrosin activity might serve as a useful tool for monitoring the irreversible sterility induced by gossypol,

Enhanced Fenton,photo-Fenton and peroxidase-like activity and stability over Fe_3O_4/g-C_3N_4 nanocomposites

We prepared the Fe3O4/g‐C3N4nanoparticles(NPs)through a simple electrostatic self‐assembly method with a3:97weight ratio to investigate their Fenton,photo‐Fenton and oxidative functionalities besides photocatalytic functionality.We observed an improvement of the Fenton and photo‐Fenton activities of the Fe3O4/g‐C3N4nanocomposites.This improvement was attributed to efficient charge transfer between Fe3O4and g‐C3N4at the heterojunctions,inhibition of electron‐hole recombination,a high surface area,and stabilization of Fe3O4against leaching by the hydrophobic g‐C3N4.The obtained NPs showed a higher degradation potential for rhodamine B(RhB)dye than those of Fe3O4and g‐C3N4.As compared to photocatalysis,the efficiency of RhB degradation in the Fenton and photo‐Fenton reactions was increased by20%and90%,respectively.Additionally,the horseradish peroxidase(HRP)activity of the prepared nanomaterials was studied with3,3,5,5‐tetramethylbenzidinedihydrochloride(TMB)as a substrate.Dopamine oxidation was also examined.Results indicate that Fe3O4/g‐C3N4nanocomposites offers more efficient degradation of RhB dye in a photo‐Fenton system compared with regular photocatalytic degradation,which requires a long time.Our study also confirmed that Fe3O4/g‐C3N4nanocomposites can be used as a potential material for mimicking HRP owing to its high affinity for TMB.These findings suggest good potential for applications in biosensing and as a catalyst in oxidation reactions.

Construction the hairpin RNA recombinant plasmids targeting human Pokemon gene

Objective： The aim of this study was to establish the foundation for studying the role of pokemon gene in tumori- genesis and development by constructing recombinant plasmids that can express small interfering RNA （siRNA） targeting human Pokemon gene. Methods： Hairpin siRNA templates targeting Pokemon gene were synthesized and cloned into plasmid vector psiRNA-Hineo. Three vectors derived siRNAs （psiRNA1, 2, 3） and one mocking psiRNAc （as control） were constructed. The recombinant Pokemon siRNA plasmids were constructed and identified using restrictive enzyme analysis and DNA sequencing, Results： Restrictive enzyme analysis and DNA sequencing revealed the successful construction of siRNA expression plasmids. Conclusion： Constructing siRNAtemplates targeting Pokemon gene may provide us with practical tools for further study the role of Pokemon gene in the development of some diseases and gene therapy of tumor.

Bromophenols from Marine Algae with Potential Anti-Diabetic Activities

Marine algae contain various bromophenols with a variety of biological activities, including antimicrobial, anticancer, and anti-diabetic effects. Here, we briefly review the recent progress in researches on the biomaterials from marine algae, emphasizing the relationship between the structure and the potential anti-diabetic applications. Bromophenols from marine algae display their hyper- glycemic effects by inhibiting the activities of protein tyrosine phosphatase 1B, ct-glucosidase, as well as other mechanisms.

Protection of Salvianolic Acid B for Human Endothelial Cells Against Hydrogen Peroxide-Induced Oxidative Damage

Salvianolic acid B(Sal B) is an active component of traditional Chinese medicine Salvia miltiorrhiza and is used to treat vascular diseases. To better understand its mechanism, the antioxidant capacities of Sal B was evaluated with human endothelial cells under oxidative stress. Human endothelial cells were pretreated with Sal B for 12 h followed by hydrogen peroxide for another 12 h. Production of reactive oxygen species (ROS), activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and concentration of glu-tathione were measured. Protective effect of Sal B on the endothelial cells from hydrogen peroxide-induced damage was observed, and ROS production in the cells was found significantly inhibited. Sal B remarkably enhanced the activities of antioxidant enzymes SOD, CAT and GPX. Furthermore, Sal B up-regulated the intracellular glu-tathione concentration. The results indicate that Sal B protected endothelial cells from oxidative stress by improving the redox status of the cells through enhancing the antioxidant enzyme activities and increasing the reductive glu-tathione concentration after the oxidative challenge.

The Study of Enzymology Characterization of Ctenopharyngodon idellus LDH Isozyme

LDH-A_4,B_4,and C_4 were isolated and purified from Ctenopharyngodon idellus tissues by means ofaffinity chromatography.The purity,amino acid content and kinetics were analyzed.The anti-LDH-A_4,B_4,and C_4 antibodies were prepared from rabbit sensitized by LDH-A_4,B_4,and C_4respectively.The LDH patterns of some freshwater fish and marine fish were identified by theantigen-antibody precipitation reaction.The homology between LDH isozyme molecules fromdifferent sources and the immunological homology of different LDH isozymes were discussed.

Co regulative effects of the cAMP/PKA and DAG/PKC signal pathways on human gastric cancer cells during differentiation induced by traditional Chinese medicines *

AIM To evaluate the role of cAMP/PKA and DAG/PKC pathways of the MGc80 3 cells treated with traditional Chinese medicine of compound Bailong preparation (Bailong).

Effect of Different Bioassay Methods on Enzymatic Characteristics of Cotton Aphid, Aphis gossypfi Glover （Hemiptera：Aphididae）

In this study, the susceptibility of three populations of cotton aphid, Aph＆ gossypii Glover （Hemiptera：Aphididae） was assayed to imidacloprid （35SC） and thiametoxam （50WG）. The involvement of metabolic enzymes in the resistance strain of cotton aphid to the neonicotinoids was determined by the biochemical biomarkers and the resistance mechanism was determined as CaE. In another study, three different bioassay experiments were designed for detecting the susceptibility of cotton aphid to imidacloprid and thiametoxam and the effect of these two insecticides on the enzymatic activity of cotton aphid was assessed in the adult aphids treated with three different bioassay methods using a modified version of the FAO dip test, residue bioassay procedure and starvation method. Our findings suggested that the type of bioassay methods is very important when aphids＇ populations assess for the resistance against the neonicotinod insecticides. It has shown the starvation method is the most reliable method compared with other methods.

Dehydrogenase Activity of Soil Microorganisms and the Total DNA Level in Soil of Different Use

The aim of the study was to find the interrelations between the activity of intracellular dehydrogenases, abundance of microorganisms, and the level of soil DNA in the Mollic Gleysol profile, with notification on the dominant DNA form （extra-or intra-cellular）, depending on the type of land use. Two neighbouring meadows were selected for investigations： one systematically cultivated and fertilized and the other deprived of any effect of anthropogenic activity, used as a control. We have demonstrated that dehydrogenase activity （DHA）, the DNA content and microbial abundance strongly depended on the type of land use. DHA exhibited a significant correlation with the DNA content （r = 0.99^＊＊＊ and r = 0.74^＊, for cultivated and control sites, respectively）. This relationship with such a high r value might suggest domination of the intracellular form of DNA in the cultivated meadow, which is also confirmed by the c.a. 13% increase in microorganism abundance in the cultivated soil. The optimal conditions for microbial activities were defined by the significant positive interrelationships between microbial abundance and the total organic carbon content, and a negative correlation with pH, redox potential and soil bulk density.

Inhibition of protein tyrosine phosphatase 1B activity by triterpenes isolated from Aceriphyllum rossii

An organic layer prepared from the seed of Aceriphyllum rossii was studied to identify the active compounds for protein tyrosine phosphatase 1B（PTP1B） inhibition.Bioassay guided fractionation resulted in the isolation of PTP1B inhibitory activity of triterpenes（1-4）.These four compounds were identified as aceriphyllic acid C（1）,aceriphyllic acid D（2）,aceriphyllic acid E（3） and aceriphyllic acid F（4）.The isolated 1-4 compounds inhibited PTP1B with IC50 values ranged from（2.1±1.5） μmol/L to（11.2±2.5） μmol/L.Kinetic analysis of PTP1B inhibition by aceriphyllic acid C（1） and aceriphyllic acid D（2） suggested that oleanane-type triterpenes inhibited PTP1B activity in a mixed-type manner.

RLKs orchestrate the signaling in plant male-female interaction

Different from animals, sessile plants are equipped with a large receptor-like kinase(RLK) superfamily. RLKs are a family of single trans-membrane proteins with divergent N-terminal extracellular domains capped by a signal peptide and C-terminal intracellular kinase. Researches in the last two decades have uncovered an increasing number of RLKs that regulate plant development, stress response and sexual reproduction, highlighting a dominant role of RLK signaling in cell-to-cell communications. Sexual reproduction in flowering plants is featured by interactions between the male gametophyte and the female tissues to facilitate sperm delivery and fertilization. Emerging evidences suggest that RLKs regulate almost every aspect of plant reproductive process, especially during pollination. Therefore, in this review we will focus mainly on the function and signaling of RLKs in plant male-female interaction and discuss the future prospects on these topics.