The innate immune response is triggered by a variety of pathogens, including viruses, and requires rapid induction of typeⅠ?interferons (IFN), such as IFNβ and IFNα. IFN induction occurs when specific pathogen moti...The innate immune response is triggered by a variety of pathogens, including viruses, and requires rapid induction of typeⅠ?interferons (IFN), such as IFNβ and IFNα. IFN induction occurs when specific pathogen motifs bind to specific cellular receptors. In non-professional immune, virally-infected cells, IFN induction is essentially initiated after the binding of dsRNA structures to TLR3 receptors or to intracytosolic RNA helicases, such as RIG-Ⅰ/MDA5. This leads to the recruitment of specific adaptors, such as TRIF for TLR3 and the mitochondrial-associated IPS-1/VISA/MAVS/CARDIF adapter protein for the RNA helicases, and the ultimate recruitment of kinases, such as MAPKs, the canonical IKK complex and the TBK1/IKKε kinases, which activate the transcription factors ATF-2/ c-jun, NF-κB and IRF3, respectively. The coordinated action of these transcription factors leads to induction of IFN and of pro-inflammatory cytokines and to the establishment of the innate immune response. HCV can cleave both the adapters TRIF and IPS-1/VISA/MAVS/ CARDIF through the action of its NS3/4A protease. This provokes abrogation of the induction of the IFN and cytokine pathways and favours viral propagation and presumably HCV chronic infection.展开更多
Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.mac...Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.maculans ascospores and assessed for phoma leaf spot development and tissue morphology and gene expression responses to infection.Rates of increase in phoma leaf spot area 8―21 d after challenge inoculation were significantly greater on water pre-treated plants than on plants pre-treated with L.biglobosa,ASM or MSB on both pre-treated leaves(local effect)and younger leaves without pre-treatment(systemic effect).Ninety-six h after challenge inoculation,the invasive hyphae of L.maculans were encircled by rings of necrotic mesophyll cells on leaves pre-treated with L. biglobosa,ASM or MSB but not those pre-treated with water.Quantification of transcript levels of genes commonly used as markers of the major defence signalling pathways(PDF1.2,PR-1,NPR1,APX, CHB4)0–96 h after L.maculans challenge inoculation showed expression patterns indicating prefer- ential activation of the jasmonate/ethylene pathway and involved induction of NPR1 locally and sys- temically in leaves of plants pre-treated with L.biglobosa ascospores.展开更多
基金grants from the Agence Nationale pour la Recherche contre le SIDA
文摘The innate immune response is triggered by a variety of pathogens, including viruses, and requires rapid induction of typeⅠ?interferons (IFN), such as IFNβ and IFNα. IFN induction occurs when specific pathogen motifs bind to specific cellular receptors. In non-professional immune, virally-infected cells, IFN induction is essentially initiated after the binding of dsRNA structures to TLR3 receptors or to intracytosolic RNA helicases, such as RIG-Ⅰ/MDA5. This leads to the recruitment of specific adaptors, such as TRIF for TLR3 and the mitochondrial-associated IPS-1/VISA/MAVS/CARDIF adapter protein for the RNA helicases, and the ultimate recruitment of kinases, such as MAPKs, the canonical IKK complex and the TBK1/IKKε kinases, which activate the transcription factors ATF-2/ c-jun, NF-κB and IRF3, respectively. The coordinated action of these transcription factors leads to induction of IFN and of pro-inflammatory cytokines and to the establishment of the innate immune response. HCV can cleave both the adapters TRIF and IPS-1/VISA/MAVS/ CARDIF through the action of its NS3/4A protease. This provokes abrogation of the induction of the IFN and cytokine pathways and favours viral propagation and presumably HCV chronic infection.
基金Supported by a Rothamsted International Fellowship to LIU ShengYi,a Royal Society China Fellowship to LIU RenHu,the UK Biotechnology and Biological Sciences Research Council(BBSRC),Department for Environment,Food and Rural Affairs(Defra),the Chadacre Trust,UK and the Ministry of Agriculture,P.R.China
文摘Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.maculans ascospores and assessed for phoma leaf spot development and tissue morphology and gene expression responses to infection.Rates of increase in phoma leaf spot area 8―21 d after challenge inoculation were significantly greater on water pre-treated plants than on plants pre-treated with L.biglobosa,ASM or MSB on both pre-treated leaves(local effect)and younger leaves without pre-treatment(systemic effect).Ninety-six h after challenge inoculation,the invasive hyphae of L.maculans were encircled by rings of necrotic mesophyll cells on leaves pre-treated with L. biglobosa,ASM or MSB but not those pre-treated with water.Quantification of transcript levels of genes commonly used as markers of the major defence signalling pathways(PDF1.2,PR-1,NPR1,APX, CHB4)0–96 h after L.maculans challenge inoculation showed expression patterns indicating prefer- ential activation of the jasmonate/ethylene pathway and involved induction of NPR1 locally and sys- temically in leaves of plants pre-treated with L.biglobosa ascospores.
