21 research outputs found

    Spatiotemporal Dynamics in a Predator–Prey Model with Functional Response Increasing in Both Predator and Prey Densities

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    In this paper, a diffusive predator–prey system with a functional response that increases in both predator and prey densities is considered. By analyzing the characteristic roots of the partial differential equation system, the Turing instability and Hopf bifurcation are studied. In order to consider the dynamics of the model where the Turing bifurcation curve and the Hopf bifurcation curve intersect, we chose the diffusion coefficients d1 and β as bifurcating parameters. In particular, the normal form of Turing–Hopf bifurcation was calculated so that we could obtain the phase diagram. For parameters in each region of the phase diagram, there are different types of solutions, and their dynamic properties are extremely rich. In this study, we have used some numerical simulations in order to confirm these ideas

    Spatiotemporal Dynamics in a Predator–Prey Model with Functional Response Increasing in Both Predator and Prey Densities

    No full text
    In this paper, a diffusive predator–prey system with a functional response that increases in both predator and prey densities is considered. By analyzing the characteristic roots of the partial differential equation system, the Turing instability and Hopf bifurcation are studied. In order to consider the dynamics of the model where the Turing bifurcation curve and the Hopf bifurcation curve intersect, we chose the diffusion coefficients d1 and β as bifurcating parameters. In particular, the normal form of Turing–Hopf bifurcation was calculated so that we could obtain the phase diagram. For parameters in each region of the phase diagram, there are different types of solutions, and their dynamic properties are extremely rich. In this study, we have used some numerical simulations in order to confirm these ideas

    Holographic entanglement entropy with Born–Infeld electrodynamics in higher dimensional AdS black hole spacetime

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    Abstract We examine the entanglement entropy in higher dimensional holographic metal/superconductor model with Born–Infeld (BI) electrodynamics. We note that the entanglement entropy is still a powerful tool to probe the critical phase transition point and the order of the phase transition in higher dimensional AdS spacetime. Due to the presence of the BI electromagnetic field, the formation of the scalar condensation becomes harder. For both operators ⟨O+⟩\langle \mathcal {O}_{+}\rangle ⟨O+⟩ and ⟨O−⟩\langle \mathcal {O}_{-}\rangle ⟨O-⟩ , we show that the entanglement entropy in the metal phase decreases as the BI factor increases, but in condensation phase the entanglement entropy increases monotonically for stronger nonlinearity of BI electromagnetic field. Furthermore, we also study the influence of the width of the subsystem on the holographic entanglement entropy and observe that with the increase of the width the entanglement entropy increases

    High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis

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    N-acetyl-5-methoxytryptamine (Melatonin), as a crucial messenger in plants, functions in adjusting biological rhythms, stress tolerance, plant growth and development. Several studies have shown the retardation effect of exogenous melatonin treatment on plant growth and development. However, the in vivo role of melatonin in regulating plant leaf growth and the underlying mechanism are still unclear. In this study, we found that high concentration of melatonin suppressed leaf growth in Arabidopsis by reducing both cell size and cell number. Further kinetic analysis of the fifth leaves showed that melatonin remarkably inhibited cell division rate. Additionally, flow cytometic analysis indicated that melatonin negatively regulated endoreduplication during leaf development. Consistently, the expression analysis revealed that melatonin regulated the transcriptional levels of key genes of cell cycle and ribosome. Taken together, this study suggests that high concentration of melatonin negatively regulated the leaf growth and development in Arabidopsis, through modulation of endoreduplication and the transcripts of cell cycle and ribosomal key genes

    AtKATANIN1 Modulates Microtubule Depolymerization and Reorganization in Response to Salt Stress in Arabidopsis

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    The microtubule cytoskeleton is a dynamic system that plays vital roles in fundamental cellular processes and in responses to environmental stumili. Salt stress induced depolymerization and reorganization of microtubules are believed to function in the promotion of survival in Arabidopsis. Microtubule-severing enzyme ATKATANIN1 (AtKTN1) is recognized as a MAP that help to maintain organized microtubule structure. To date, whether AtKTN1 is involved in response to salt stress in Arabidopsis remains unknown. Here, our phenotypic analysis showed that the overexpression of AtKTN1 decreased tolerance to salt stress, whereas the knock-out of AtKTN1 increased salt tolerance in the early stage but decreased salt tolerance in the later stage. Microscopic analysis revealed that microtubule organization and dynamics are distorted in both overexpression and mutant cells which, in turn, resulted in an abnormal disassembly and reorganization under salt stress. Moreover, qRT analysis revealed that stress-responsive genes were down-regulated in overexpression and mutant cells compared to WT cells under salt stress. Taken together, our results indicated roles of AtKTN1 in modulating microtubule organization, salt-stress induced microtubule disruption and recovery, and its involvement in stress-related signaling pathways

    Roles of CgEde1 and CgMca in Development and Virulence of <i>Colletotrichum gloeosporioides</i>

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    Anthracnose, induced by Colletotrichum gloeosporioides, poses a substantial economic threat to rubber tree yields and various other tropical crops. Ede1, an endocytic scaffolding protein, plays a crucial role in endocytic site initiation and maturation in yeast. Metacaspases, sharing structural similarities with caspase family proteases, are essential for maintaining cell fitness. To enhance our understanding of the growth and virulence of C. gloeosporioides, we identified a homologue of Ede1 (CgEde1) in C. gloeosporioides. The knockout of CgEde1 led to impairments in vegetative growth, conidiation, and pathogenicity. Furthermore, we characterized a weakly interacted partner of CgEde1 and CgMca (orthologue of metacaspase). Notably, both the single mutant ΔCgMca and the double mutant ΔCgEde1/ΔCgMca exhibited severe defects in conidiation and germination. Polarity establishment and pathogenicity were also disrupted in these mutants. Moreover, a significantly insoluble protein accumulation was observed in ΔCgMca and ΔCgEde1/ΔCgMca strains. These findings elucidate the mechanism by which CgEde1 and CgMca regulates the growth and pathogenicity of C. gloeosporioides. Their regulation involves influencing conidiation, polarity establishment, and maintaining cell fitness, providing valuable insights into the intricate interplay between CgEde1 and CgMca in C. gloeosporioides

    Dicer-like Proteins Regulate the Growth, Conidiation, and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis

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    Colletotrichum gloeosporioides from Hevea brasiliensis is the hemibiotrophic fungi which could cause anthracnose in rubber trees. Dicer like proteins (DCL) were the core enzymes for generation of small RNAs. In the present study, the knocking-out mutants of two dicer like proteins encoding genes of C. gloeosporioides were constructed; and functions of two proteins were investigated. The results showed that DCL play important roles in regulating the growth, conidiation and pathogenicity of C. gloeosporioides; and there is a functional redundancy between DCL1 and DCL2. Microscopy analysis and DAB staining revealed that loss of penetration ability into the host cells, instead of the decreased growth rate, was the main cause for the impaired pathogenicity of the ΔDcl1ΔDcl2 double mutant. Proteomics analysis suggested that DCL proteins affected the expression of functional proteins to regulating multiple biological processes of C. gloeosporioides. These data lead to a better understanding of the functions of DCL proteins in regulating the development and pathogenesis of C. gloeosporioides

    SGE1 is involved in conidiation and pathogenicity of Fusarium oxysporum f. sp. cubense

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    The ascomycete fungus Fusarium oxysporum f. sp. cubense race 4 (Foc TR4) causes vascular wilt diseases in banana (Musa spp.). In the present study, the roles of SGE1 in regulating growth, conidiation, and pathogenicity of Foc TR4 were investigated. Deletion of SGE1 did not influence vegetative growth, but impaired the conidiation of Foc TR4. Besides, the SGE1 deletion mutant basically lost pathogenicity on banana plantlets. Observation under the microscope indicated that the penetration and colonization processes were severely impaired in the SGE1 deletion mutant. Proteomics analysis suggested that SGE1 regulated the production of a series of proteins of Foc TR4. Taking together, our results suggest that SGE1 plays important roles in regulating conidiation and pathogenicity in fungal pathogen Foc TR4.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

    BAS2 Is Required for Conidiation and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis

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    The hemibiotrophic fungi Colletotrichum gloeosporioides can cause anthracnose in rubber trees. By searching the genome of the fungal pathogen, the BAS2 encoding a biotrophy-associated secreted protein was identified. In the present study, the knockout mutants of BAS2 were constructed and the functions of BAS2 were investigated. The in vitro assays showed that BAS2 was not necessary for vegetative growth but was important for normal asexual reproduction in C. gloeosporioides. Pathogenicity assays suggested that BAS2 was involved in the process of the pathogen penetrating into the host tissue. Subcellular localization analysis revealed that BAS2 showed secretional characteristics in the fungi, and BAS2 mainly function as a cytoplasmic protein after being secreted into the host cell. Extracellular proteomics analysis revealed that BAS2 was required for the secretion of a series of proteins, which were important for the pathogenicity of C. gloeosporioides. These data lead to a better understanding of the biotrophy-associated secreted protein in regulating the pathogenesis of C. gloeosporioides
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