20 research outputs found

    Изменение параметров процесса выброса угля и газа в зависимости от длины шпуров для отбойки угля и породы

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    Виконано чисельне моделювання процесу викиду вугілля та метану у вибої одиночної гірничої виробки, що проводиться буропідривним способом. Розглянуто ініціювання процесу викиду у випадках різної довжини шпурів для відбивання вугілля та породи. Проаналізовано зміну розподілів коефіцієнтів проникності поперед вибоєм, значень тиску газу та швидкості утворення порожнини викиду вугілля та газу.Numerical modeling of process of coal and methane outburst in a working face of single opening, what is driving by drill and fire system, is executed. Initiation of coal and methane outburst process in cases of various length of blast-holes is observed. Change of distribution of permeability coefficient ahead of a face, pressure values and speed of formation of outburst cavity is analysed

    Insect eggs trigger systemic acquired resistance against a fungal and an oomycete pathogen.

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    Plants are able to detect insect eggs deposited on leaves. In Arabidopsis, eggs of the butterfly species Pieris brassicae (common name large white) induce plant defenses and activate the salicylic acid (SA) pathway. We previously discovered that oviposition triggers a systemic acquired resistance (SAR) against the bacterial hemibiotroph pathogen Pseudomonas syringae. Here, we show that insect eggs or treatment with egg extract (EE) induce SAR against the fungal necrotroph Botrytis cinerea BMM and the oomycete pathogen Hyaloperonospora arabidopsidis Noco2. This response is abolished in ics1, ald1 and fmo1, indicating that the SA pathway and the N-hydroxypipecolic acid (NHP) pathway are involved. Establishment of EE-induced SAR in distal leaves potentially involves tryptophan-derived metabolites, including camalexin. Indeed, SAR is abolished in the biosynthesis mutants cyp79B2 cyp79B3, cyp71a12 cyp71a13 and pad3-1, and camalexin is toxic to B. cinerea in vitro. This study reveals an interesting mechanism by which lepidopteran eggs interfere with plant-pathogen interactions

    Insect eggs trigger systemic acquired resistance against a fungal and an oomycete pathogen

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    Plants are able to detect insect eggs deposited on leaves. In Arabidopsis, eggs of the butterfly species Pieris brassicae (common name large white) induce plant defenses and activate the salicylic acid (SA) pathway. We previously discovered that oviposition triggers a systemic acquired resistance (SAR) against the bacterial hemibiotroph pathogen Pseudomonas syringae. Here, we show that insect eggs or treatment with egg extract (EE) induce SAR against the fungal necrotroph Botrytis cinerea BMM and the oomycete pathogen Hyaloperonospora arabidopsidis Noco2. This response is abolished in ics1, ald1 and fmo1, indicating that the SA pathway and the N-hydroxypipecolic acid (NHP) pathway are involved. Establishment of EE-induced SAR in distal leaves potentially involves tryptophan-derived metabolites, including camalexin. Indeed, SAR is abolished in the biosynthesis mutants cyp79B2 cyp79B3, cyp71a12 cyp71a13 and pad3-1, and camalexin is toxic to B. cinerea in vitro. This study reveals an interesting mechanism by which lepidopteran eggs interfere with plant–pathogen interactions

    Multiple functional self-association interfaces in plant TIR domains

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    Toll/interleukin-1 receptor/resistance protein (TIR) domains are present in plant and animal innate immunity receptors and appear to play a scaffold function in defense signaling. In both systems, self-association of TIR domains is crucial for their function. In plants, the TIR domain is associated with intracellular immunity receptors, known as nucleotide-binding oligomerization domain-like receptors (NLRs). Previous studies from several plant NLRs have identified two distinct interfaces that are required for TIR:TIR dimerization in different NLRs. We show that the two interfaces previously identified are both important for self-association and defense signaling of multiple TIR–NLR proteins. Collectively, this work suggests that there is a common mechanism of TIR domain self-association in signaling across the TIR–NLR class of receptor proteins.This research was supported by the Australian Research Council (ARC) Discovery Projects (DP120100685, DP120103558, and DP160102244) and the National Science Foundation (NSF-IOS-1146793 to B.J.S.). B.K. is a National Health and Medical Research Council Research Fellow (1003325 and 1110971). M.B. and S.J.W. are recipients of ARC Discovery Early Career Research Awards (DE130101292 and DE160100893, respectively)

    <i>Myriophyllum</i> <i>rubricaule</i> sp. nov., a <i>M. aquaticum</i> look-alike only known in cultivation

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    A confusingly labeled water-milfoil of obscure status, known only in cultivation, is here formally described as a new species, Myriophyllum rubricaule Valk. &amp; Duist. sp. nov. This species has fully replaced M. aquaticum in the horticultural trade in Europe since the addition of M. aquaticum to the list of invasive alien species of Union concern (EU regulation no. 1143/2014) in 2016. This manuscript provides a morphological description of M. rubricaule sp. nov., and its distinction from M. aquaticum is further supported by molecular data (chloroplast and nuclear loci).</p

    Myriophyllum rubricaule sp. nov., a M. aquaticum look-alike only known in cultivation

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    A confusingly labeled water-milfoil of obscure status, known only in cultivation, is here formally described as a new species, Myriophyllum rubricaule Valk. & Duist. sp. nov. This species has fully replaced M. aquaticum in the horticultural trade in Europe since the addition of M. aquaticum to the list of invasive alien species of Union concern (EU regulation no. 1143/2014) in 2016. This manuscript provides a morphological description of M. rubricaule sp. nov., and its distinction from M. aquaticum is further supported by molecular data (chloroplast and nuclear loci)

    Extracellular recognition of oomycetes during biotrophic infection of plants

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    Extracellular recognition of pathogens by plants constitutes an important early detection system in plant immunity. Microbe-derived molecules, also named patterns, can be recognized by pattern recognition receptors (PRRs) on the host cell membrane that trigger plant immune responses. Most knowledge on extracellular pathogen detection by plants comes from research on bacterial and fungal pathogens. For oomycetes, that comprise some of the most destructive plant pathogens, mechanisms of extracellular pattern recognition have only emerged recently. These include newly recognized patterns, e.g., cellulose-binding elicitor lectin, necrosis and ethylene-inducing peptide 1-like proteins (NLPs), and glycoside hydrolase 12, as well as their receptors, e.g., the putative elicitin PRR elicitin response and the NLP PRR receptor-like protein 23. Immunity can also be triggered by the release of endogenous host-derived patterns, as a result of oomycete enzymes or damage. In this review we will describe the types of patterns, both pathogen-derived exogenous and plant-derived endogenous ones, and what is known about their extracellular detection during (hemi-)biotrophic oomycete infection of plants

    Nep1-like proteins from three kingdoms of life act as a microbe-associated molecular pattern in Arabidopsis

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    Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by a wide range of plant-associated microorganisms. They are best known for their cytotoxicity in dicot plants that leads to the induction of rapid tissue necrosis and plant immune responses. The biotrophic downy mildew pathogen Hyaloperonospora arabidopsidis encodes 10 different noncytotoxic NLPs (HaNLPs) that do not cause necrosis. We discovered that these noncytotoxic NLPs, however, act as potent activators of the plant immune system in Arabidopsis thaliana. Ectopic expression of HaNLP3 in Arabidopsis triggered resistance to H. arabidopsidis, activated the expression of a large set of defense-related genes, and caused a reduction of plant growth that is typically associated with strongly enhanced immunity. N- and C-terminal deletions of HaNLP3, as well as amino acid substitutions, pinpointed to a small central region of the protein that is required to trigger immunity, indicating the protein acts as a microbe-associated molecular pattern (MAMP). This was confirmed in experiments with a synthetic peptide of 24 aa, derived from the central part of HaNLP3 and corresponding to a conserved region in type 1 NLPs that induces ethylene production, a well-known MAMP response. Strikingly, corresponding 24-aa peptides of fungal and bacterial type 1 NLPs were also able to trigger immunity in Arabidopsis. The widespread phylogenetic distribution of type 1 NLPs makes this protein family (to our knowledge) the first proteinaceous MAMP identified in three different kingdoms of life

    <i>Pp</i>NLP nlp20 orthologous peptides from bacterial, oomycete and fungal organisms exhibit comparable immunogenic activities in <i>Arabidopsis</i>.

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    <p>Synthetic peptides corresponding to nlp20 (<i>Pp</i>NLP) orthologous sequences from another oomycete, <i>Pythium aphanidermatum</i> (nlp20 (<i>Pya</i>NLP)), from fungi <i>Fusarium oxysporum</i> (nlp20 (<i>Fo</i>NLP)) and <i>Botrytis cinerea</i> (nlp20 (<i>Bc</i>NLP)), and bacterial species <i>Bacillus halodurans</i> (nlp20 (<i>Bh</i>NLP)) and <i>Bacillus subtilis</i> (nlp20 (<i>Bs</i>NLP)) were tested for their abilities to trigger ethylene formation (EC<sub>50</sub> values), MAPK activation, production of reactive oxygen species (oxidative burst), <i>PR1::GUS</i> expression, deposition of callose and seedling growth inhibition. +, activation; −, no activation.</p><p><i>Pp</i>NLP nlp20 orthologous peptides from bacterial, oomycete and fungal organisms exhibit comparable immunogenic activities in <i>Arabidopsis</i>.</p

    Identification of a minimum immunogenic epitope within <i>Pp</i>NLP.

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    <p>Synthetic peptides derived from a <i>Pp</i>NLP fragment spanning amino acid residues 84–131 were tested for their abilities to trigger ethylene formation in <i>Arabidopsis</i> leaves. EC<sub>50</sub> values were determined based upon using at least six different peptide concentrations. Peptides c and j are as indicated in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004491#ppat-1004491-g002" target="_blank">Figure 2</a>. Peptides 1–14 represent truncated versions of <i>Pp</i>NLP fragment 84–131. Peptides 15–38 are truncated versions of <i>Pp</i>NLP fragment 84–131 in which single amino acid residues are replaced by alanine residues (in bold). Data represent means ± SD of three replicates. Assays were performed three times with similar results.</p><p>Identification of a minimum immunogenic epitope within <i>Pp</i>NLP.</p
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