具有农药活性的微生物源核苷类化合物

微生物天然产物在新农药的研究与开发中占据着重要的地位。核苷作为一类重要的生理活性物质,具有丰富多样的结构及生物活性。本文对微生物来源的具有农药活性的核苷类化合物进行总结,重点综述了具有农药活性的微生物源嘧啶或嘌呤、核苷及其衍生物及核苷酸类似物等三类微生物源核苷类化合物,分别对其来源、结构多样性、农药活性及杀虫、杀菌及抗病毒作用机制进行了概括,以期对新型农用抗生素的开发及新农药创制提供一些有益的借鉴。

Selective probes targeting c-MYC Pu22 G-quadruplex and their application in live mice imaging

Several probes containing benzothiazole-guided conjugated systems(BGCS) were designed and synthesized, and two molecules(BGCS5 and BGCS6) of which were discovered as selective probes targeting c-MYC Pu22 G-quadruplex DNA. The fluorescence intensity of BGCS5 and BGCS6 in the presence of c-MYC Pu22 far exceeds that of the typical G4 probe TO1. Especially, the fluorescence of BGCS6 increased almost193-fold in the presence of c-MYC Pu22 G4 compared to that alone in aqueous buffer condition with almost no fluorescence and 10–30 folds than those in the presence of other DNAs, which will be useful tools for disease detection in mammals.

Screening of novel synthetic derivatives of dehydroepiandrosterone for antivirals against flaviviruses infections

Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem.Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interventions.Dehydroepiandrosterone(DHEA)is a natural occurring adrenal-derived steroid in the human body that has been associated in protection against various infections.In the present study,the plaque assay based primary screening was conducted on 32 synthetic derivatives of DHEA against Japanese encephalitis virus(JEV)to identify potent anti-flaviviral compounds.Based on primary screening,HAAS-AV3026 and HAAS-AV3027 were selected as hits from DHEA derivatives that exhibited strong antiviral activity against JEV(IC_(50)=2.13 and 1.98μmol/L,respectively)and Zika virus(ZIKV)(IC_(50)=3.73 and 3.42μmol/L,respectively).Mechanism study indicates that HAAS-AV3026 and HAAS-AV3027 do not exhibit inhibitory effect on flavivirus binding and entry process,while significantly inhibit flavivirus infection at the replication stage.Moreover,indirect immunofluorescence assay,Western blot analyses,and quantitative reverse transcription-PCR(qRT-PCR)revealed a potent antiviral activity of DHEA derivatives hits against JEV and ZIKV in terms of inhibition of viral infection,protein production,and viral RNA synthesis in Vero cells.Taken together,our results may provide a basis for the development of new antivirals against flaviviruses.

Sc(OTf)_(3)-catalyzed synthesis of polysubstituted furans from acylacetonitriles and renewable acetol

A[3+2]cyclization reaction of acylacetonitriles and hydroxyacetone was developed by using Sc(OTf)_(3)as a catalyst to synthesize some furan derivatives.Bifunctional C2-based acetals,such asα-bromoacetaldehyde acetal,1,4-dithiane-2,5-diol and glycolaldehyde diethyl acetal,also reacted readily as alternative counterpart reagents to acylacetonitriles.The established reactions can be used to synthesize a well-known fungicide,fenfuram.Antifungal activity investigation against four common plant funguses indicated that some of the obtained furan products furnish general and high biological activities.