Selenium Regulates Antioxidant Capacities and Diterpenoid Biosynthesis in the Medicinal Plant Isodon rubescens

Dōng líng căo,the dried aboveground parts of Isodon rubescens(Hemls.)Hara.,is commonly consumed as a med-icinal decoction or tea beverage.Natural beverages can be an important source of human dietary selenium(Se).However,how I.rubescens plants respond to exogenous Se remains unknown.In this study,a pot cultivation experiment was employed to investigate the phenotypic and physiological responses of I.rubescens plants exposed to Se.Fifteen days after applying different concentrations of sodium selenate to the soil,the Se enrichment capa-city,growth indices,antioxidant capacities,and the content offlavonoids and diterpenoids were measured in the plants.Further,the oridonin content was quantified using the high-performance liquid chromatography method,and the expression levels of key diterpenoid synthesis genes were analyzed by quantitative real-time PCR(qRT-PCR).I.rubescens plants efficiently accumulated Se,with the Se content increasing proportionally to the applied dose,reaching levels of nearly 200 mg·kg^(-1) dry leaves as Se concentration increased.None of the three Se treat-ments significantly altered the phenotypic indices,except a longer root length occurred in the 3μM·kg^(-1) Se group.Among three Se doses,6μM·kg^(-1) Se gave the highest accumulation offlavonoids,diterpenoids,and oridonin,with the increase of 2.0-,1.8-,and 1.9-fold in aboveground parts,respectively.Selenium application boosted the activities of antioxidant enzymes and antioxidant capacities according to 2,2-Diphenyl-1-picrylhydrazyl(DPPH),ferric reducing/antioxidant power,and tea brewing color experiments.Four key synthase genes were upregulated significantly by 6μM·kg^(-1) Se treatment,notably 1-deoxy-D-xylulose 5-phosphate reductoisomerase(IrDXR),with a 5-fold increase,and kaurene synthase-like 4(IrKSL4),with a 6-fold increase.Thus,Se application in I.rubescens cultivation may be a potential biofortification method to supplement Se while increasingflavonoid and diterpenoid contents.

冯诺依曼型元胞自动机和自指语句

熊明(2020)把初等元胞自动机与自指语句结合起来进行研究,建立起二者在演化过程方面的紧密关联。沿此路径,本文主要考虑一类称为总和型的二维冯诺依曼型元胞自动机,给出其自指语句表达形式。并且通过利用自指语句的性质,寻找元胞自动机相对应的不动点,将其与自指悖论相联系。同时,通过分析其演化过程的(不)稳定性特征,进行了相应的分类。

Cross-resistance and genetics of field-evolved resistance to chlorfenapyr in Plutella xylostella

Chlorfenapyr is a broad-spectrum halogenated pyrrole insecticide with a unique mode of action.Due to the misuse and overuse of this chemical,resistance has been reported in several arthropods,including Plutella xylostella,which is one of the most destructive insect pests afflicting crucifers worldwide.A better understanding of the cross-resistance and genetics of field-evolved chlorfenapyr resistance could effectively guide resistance management practices.Here,the chlorfenapyr resistance of a fieldderived population of P xylostella was introgressed into the susceptible IPP-S strain using a selection-assisted multigenerational backcrossing approach.The constructed nearisogenic strain,TH-BCsF2,shared 98.4%genetic background with the recurrent parent IPP-S strain.The TH-BCsF2 strain showed 275-fold resistance to chlorfenapyr,but no significant cross-resistance to spinosad,abamectin,chlorpyrifos,β-cypermethrin,indoxacarb,chlorantraniliprole,or broflanilide(no more than 4.2-fold).Genetic analysis revealed that resistance was autosomal,incompletely dominant,and conferred by 1 major gene or a few tightly linked loci.The synergism of metabolic inhibitors(PBO,DEM,and DEF)to chlorfenapyr was very weak(<1.7-fold),and the metabolic enzyme activities in the TH-BCsF2 strain were not significantly elevated compared with the IPP-S strain.The results enhances our understanding of the genetic traits of chlorfenapyr resistance,and provides essential information for improving resistance management strategies.

C1QTNF5 is a novel attachment factor that facilitates the entry of influenza A virus

Influenza A virus(IAV)binds sialic acid receptors on the cell surface to enter the host cells,which is the key step in initiating infection,transmission and pathogenesis.Understanding the factors that contribute to the highly efficient entry of IAV into human cells will help elucidate the mechanism of viral entry and pathogenicity,and provide new targets for intervention.In the present study,we reported a novel membrane protein,C1QTNF5,which binds to the hemagglutinin protein of IAV and promotes IAV infection in vitro and in vivo.We found that the HA1 region of IAV hemagglutinin is critical for the interaction with C1QTNF5 protein,and C1QTNF5 interacts with hemagglutinin mainly through its N-terminus(1–103 aa).In addition,we further demonstrated that overexpression of C1QTNF5 promotes IAV entry,while blocking the interaction between C1QTNF5 and IAV hemagglutinin greatly inhibits viral entry.However,C1QTNF5 does not function as a receptor to mediate IAV infection in sialic acid-deficient CHO-Lec2 cells,but promotes IAV to attach to these cells,suggesting that C1QTNF5 is an important attachment factor for IAV.This work reveals C1QTNF5 as a novel IAV attachment factor and provides a new perspective for antiviral strategies.

AIMP2 restricts EV71 replication by recruiting SMURF2 to promote the degradation of 3D polymerase

Hand,foot and mouth disease(HFMD),mainly caused by enterovirus 71(EV71),has frequently occurred in the Asia-Pacific region,posing a significant threat to the health of infants and young children.Therefore,research on the infection mechanism and pathogenicity of enteroviruses is increasingly becoming important.The 3D polymerase,as the most critical RNA-dependent RNA polymerase(RdRp)for EV71 replication,is widely targeted to inhibit EV71 infection.In this study,we identified a novel host protein,AIMP2,capable of binding to 3D polymerase and inhibiting EV71 infection.Subsequent investigations revealed that AIMP2 recruits the E3 ligase SMURF2,which mediates the polyubiquitination and degradation of 3D polymerase.Furthermore,the antiviral effect of AIMP2 extended to the CVA16 and CVB1 serotypes.Our research has uncovered the dynamic regulatory function of AIMP2 during EV71 infection,revealing a novel antiviral mechanism and providing new insights for the development of antienteroviral therapeutic strategies.

ANXA2 Facilitates Enterovirus 71 Infection by Interacting with 3D Polymerase and PI4KB to Assist the Assembly of Replication Organelles

Similar to that of other enteroviruses, the replication of enterovirus 71(EV71) occurs on rearranged membranous structures called replication organelles(ROs). Phosphatidylinositol 4-kinase Ⅲ(PI4KB), which is required by enteroviruses for RO formation, yields phosphatidylinositol-4-phosphate(PI4P) on ROs. PI4P then binds and induces conformational changes in the RNA-dependent RNA polymerase(Rd Rp) to modulate Rd Rp activity. Here, we targeted 3D polymerase, the core enzyme of EV71 ROs, and found that the host factor Annexin A2(ANXA2) can interact with 3 D polymerase and promote the replication of EV71. Then, an experiment showed that the annexin domain of ANXA2, which possesses membranebinding capacity, mediates the interaction of ANXA2 with EV71 3 D polymerase. Further research showed that ANXA2 is localized on ROs and interacts with PI4KB. Overexpression of ANXA2 stimulated the formation of PI4P, and the level of PI4P was decreased in ANXA2-knockout cells. Furthermore, ANXA2, PI4KB, and 3D were shown to be localized to the viral RNA replication site, where they form a higher-order protein complex, and the presence of ANXA2 promoted the PI4 KB-3D interaction. Altogether, our data provide new insight into the role of ANXA2 in facilitating formation of the EV71 RNA replication complex.

Dyngo-4a protects mice from rotavirus infection by affecting the formation of dynamin 2 oligomers

Rotavirus is the most common etiologic agent of severe diarrhea in infants and young children and causes more than 200,000 deaths annually worldwide[1,2].Licensed rotavirus vaccines can provide more than 50%protection against rotavirus infection,and currently available etiological treatments for rotavirus gastroenteritis mainly involve the use of oral rehydration solution and zinc supplementation[3].However,targeted interventions are in great need for rotavirus-induced gastroenteritis control.