Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals...Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals, such as Pb, Cu, Ag, and Cr, would result in severe defects of chemotaxis to water-soluble attractants of NaCl, cAMP, and biotin. Moreover, the morphology of ASE neuron structures as observed by relative fluorescent intensities and relative size of fluorescent puncta of cell bodies, relative lengths of sensory endings in ASE neurons, and the expression patterns of che-1 were obviously altered in metal exposed animals when they meanwhile exhibited obvious chemotaxis defects to water-soluble attractants. In addition, the dendrite morphology could be noticeably changed in animals exposed to 150 μmol/L of Pb, Cu, and Ag. Furthermore, we observed significant decreases of chemotaxis to water-soluble attractants in Pb exposed che-1 mutant at concentrations more than 2.5 μmol/L, and in Cu, Ag, and Cr exposed che-1 mutant at concentrations more than 50 μmol/L. Therefore, impairment of the ASE neuron structures and functions may largely contribute to the appearance of chemotaxis defects to water-soluble attractants in metal exposed nematodes.展开更多
The existence of positive solutions and the global attractivity of the difference equation Δy n=r ny nK-y n-l n K-cy n-l n are investigated. And some sufficient conditions are obtained,which greatly imp...The existence of positive solutions and the global attractivity of the difference equation Δy n=r ny nK-y n-l n K-cy n-l n are investigated. And some sufficient conditions are obtained,which greatly improve and extend the known results.展开更多
The NPR1(NONEXPRESSOR OF PATHOGENESIS RELATED GENES1)gene has a central role in the long-lasting,broad-spectrum defense response known as systemic acquired resistance(SAR).When overexpressed in a transgenic context in...The NPR1(NONEXPRESSOR OF PATHOGENESIS RELATED GENES1)gene has a central role in the long-lasting,broad-spectrum defense response known as systemic acquired resistance(SAR).When overexpressed in a transgenic context in Arabidopsis thaliana,this gene enhances resistance to a number of biotic and abiotic stresses.Its position as a key regulator of defense across diverse plant species makes NPR1 a strong candidate gene for genetic engineering disease and stress tolerance into other crops.High-value horticultural crops face many new challenges from pests and pathogens,and their emergence exceeds the pace of traditional breeding,making the application of NPR1-based strategies potentially useful in fruit and vegetable crops.However,plants overexpressing NPR1 occasionally present detrimental morphological traits that make its application less attractive.The practical utility of NPR-based approaches will be a balance of resistance gains versus other losses.In this review,we summarize the progress on the understanding of NPR1-centered applications in horticultural and other crop plants.We also discuss the effect of the ectopic expression of the A.thaliana NPR1 gene and its orthologs in crop plants and outline the future challenges of using NPR1 in agricultural applications.展开更多
基金supported by the National Natural Science Foundation of China (No. 30771113, 30870810)the Program for New Century Excellent Talents in Universityprovided by the Caenorhabdits Genetics Center (funded by the NIH National Center for Research Resource, USA).
文摘Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals, such as Pb, Cu, Ag, and Cr, would result in severe defects of chemotaxis to water-soluble attractants of NaCl, cAMP, and biotin. Moreover, the morphology of ASE neuron structures as observed by relative fluorescent intensities and relative size of fluorescent puncta of cell bodies, relative lengths of sensory endings in ASE neurons, and the expression patterns of che-1 were obviously altered in metal exposed animals when they meanwhile exhibited obvious chemotaxis defects to water-soluble attractants. In addition, the dendrite morphology could be noticeably changed in animals exposed to 150 μmol/L of Pb, Cu, and Ag. Furthermore, we observed significant decreases of chemotaxis to water-soluble attractants in Pb exposed che-1 mutant at concentrations more than 2.5 μmol/L, and in Cu, Ag, and Cr exposed che-1 mutant at concentrations more than 50 μmol/L. Therefore, impairment of the ASE neuron structures and functions may largely contribute to the appearance of chemotaxis defects to water-soluble attractants in metal exposed nematodes.
文摘The existence of positive solutions and the global attractivity of the difference equation Δy n=r ny nK-y n-l n K-cy n-l n are investigated. And some sufficient conditions are obtained,which greatly improve and extend the known results.
基金The authors are grateful to the doctoral fellowship from CAPES(Brazilian National Council for the Improvement of Higher Education–Grant Procs.BEX 5640/10–5)to K.J.P.S.a sabbatical scholarship from the University of Tabriz,Iran to N.M.a grant from the Florida Strawberry Research and Education Foundation to Z.M.and K.M.F.
文摘The NPR1(NONEXPRESSOR OF PATHOGENESIS RELATED GENES1)gene has a central role in the long-lasting,broad-spectrum defense response known as systemic acquired resistance(SAR).When overexpressed in a transgenic context in Arabidopsis thaliana,this gene enhances resistance to a number of biotic and abiotic stresses.Its position as a key regulator of defense across diverse plant species makes NPR1 a strong candidate gene for genetic engineering disease and stress tolerance into other crops.High-value horticultural crops face many new challenges from pests and pathogens,and their emergence exceeds the pace of traditional breeding,making the application of NPR1-based strategies potentially useful in fruit and vegetable crops.However,plants overexpressing NPR1 occasionally present detrimental morphological traits that make its application less attractive.The practical utility of NPR-based approaches will be a balance of resistance gains versus other losses.In this review,we summarize the progress on the understanding of NPR1-centered applications in horticultural and other crop plants.We also discuss the effect of the ectopic expression of the A.thaliana NPR1 gene and its orthologs in crop plants and outline the future challenges of using NPR1 in agricultural applications.
