Structural engineering of antimicrobials for optimal broad-spectrum activity

Antimicrobial materials are a crucial component in eradicating and managing the spread of infectious diseases.They are expected to act on a broad-spectrum of microbes,including emerging pathogens which could cause the next Disease X.Herein,we reassessed a series of antimicrobial imidazolium polymers on our shelves and uncovered extended functionality through dual modes of action.By redesigning their structures,a truly broadspectrum antimicrobial material with optimized activity against bacteria(G+ve,G-ve)and fungi,as well as enveloped and non-enveloped viruses was developed.We demonstrated that the imidazolium polymer exhibits dual modes of function against microbes:targeting the microbial membrane and binding DNA.The latter DNA binding affinity was found to be key against non-enveloped viruses.With this insight,we designed small molecule compounds that exhibited optimum broad-spectrum antimicrobial activity and excellent efficacy against ESKAPE group of pathogens that are responsible for some of the deadliest nosocomial infections worldwide.Our results could also shed light on the design of broad-spectrum antimicrobial compounds against Disease X.

Influencing in vitro clonal propagation of Chonemorpha fragrans(moon) Alston by culture media strength,plant growth regulators,carbon source and photo periodic incubation

Chonemorpha fragrans is an endangered medicinal woody climber,regarded among alternative plant sources of camptothecin.Camptothecin is a monoterpene indole anti-cancer alkaloid with annual trade value of over three billion U.S.dollars in the recent,and is used in the production of its analog drugs approved for the chemotherapy of cancer of varied types.Effects of plant growth regulators,culture media strength and photoperi-odic duration on the micropropagation ef ciency of C.fragrans from nodal segment explants were studied on Murashige and Skoog(MS)medium amended with Thidiazuron(TDZ),Benzylaminopurine(BAP)or Kinetin(Kin).Thidiazuron was more ef cient over BAP and Kin when half basal MS medium was used over full or quarter strength.Results of carbon source experiment showed sucrose as the most effective over glucose,fructose,and maltose in the clonal production.Studies on the photope-riodic incubation duration showed 12 h as the best light period and sub or supra-optimal resulted in the production of abnormal and albino micro shoots.Experimental results on the evaluation of physiological,biochemical parameters showed the role of pigment molecules and antioxidant systems in the production of albino micro shoots.

Studies of Photocatalytic Kinetics on the Degradation of Bisphenol A （BPA） by Immobilized ZnO Nanoparticles in Aerated Photoreactors

The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reactor. The conditions of photocatalytic degradation were optimized. Direct photocatalytic degradation of BPA was undertaken in an aqueous solution containing ZnO nanoparticles under the optimized experimental conditions. The effects of various factors, such as initial BPA concentrations, initial pH values and various anions （CI, NO3, COa2, SO42-, HCO3＂） were investigated. In the case of the nanoparticles derived films, the photocatalytic efficiency was found not to be remarkably related with the calcination temperature employed in the coating process. Screen-printed ZnO nanoparticles films obtained in the optimal processing conditions showed that the photocatalytic activity is comparable to ZnO nanoparticles in aqueous suspensions. Over 90% degradation efficiency of BPA was achieved under the optimum conditions. The degradation rates in all photocatalytic experiments were linear with the degradation efficiencies of BPA by regression analysis （r ≥ 0.99）. The results showed that the degradation kinetics of BPA in the reactor with immobilized nano-ZnO film as photocatalyst was in agreement with a pseudo-first order rate law.

Direct acetylation of a conserved threonine of RIN4 by the bacterial effector HopZ5 or AvrBsT activates RPM1-dependent immunity in Arabidopsis

Plant pathogenic bacteria deliver effectors into plant cells to suppress immunity and promote pathogen survival;however, these effectors can be recognised by plant disease resistance (R) proteins to activate innate immunity. The bacterial acetyltransferase effectors HopZ5 and AvrBsT trigger immunity in Arabidopsis thaliana genotypes lacking SUPPRESSOR OF AVRBST-ELICITED RESISTANCE 1 (SOBER1). Using an Arabidopsis accession, Tscha-1, that naturally lacks functional SOBER1 but is unable to recognise HopZ5, we demonstrate that RESISTANCE TO P. SYRINGAE PV MACULICOLA 1 (RPM1) and RPM1-INTERACTING PROTEIN 4 (RIN4) are indispensable for HopZ5- or AvrBsT-triggered immunity. Remarkably, T166 of RIN4, the phosphorylation of which is induced by AvrB and AvrRpm1, was directly acetylated by HopZ5 and AvrBsT. Furthermore, we demonstrate that the acetylation of RIN4 T166 is required and sufficient for HopZ5- or AvrBsT-triggered RPM1-dependent defence activation. Finally, we show that SOBER1 interferes with HopZ5- or AvrBsT-triggered immunity by deacetylating RIN4 T166. We have thus elucidated detailed molecular mechanisms underlying the activation and suppression of plant innate immunity triggered by two bacterial acetyltransferases, HopZ5 and AvrBsT from different bacterial pathogens.

环境友好型AZ31B镁合金交流微弧氧化的表征(英文)

研究了一种新的AZ31B镁合金交流电微弧氧化（MAO）工艺，采用了对环境更加友好的含硅酸盐的稀碱溶液作为电解质。结果发现氧化过程分为2个阶段，膜厚与微弧氧化时间呈抛物线关系。形貌观察表明，微弧氧化膜由一个致密层和一个多孔层组成。致密层的厚度约占整个膜厚的40％，膜表面的20％均匀分布着直径1～3岬的孔。动电位极化测量显示，该新型微弧氧化膜的耐蚀性有明显提高，腐蚀电流降低了2个数量级，而自腐蚀电位正移了0．07V。盐雾试验结果同样证实微弧氧化膜的耐蚀性有大幅度提高。