Plants are constantly threatened by potential pathogens. In order to optimize the output of defense against pathogens with distinct lifestyles, plants depend on hormonal networks to fine-tune ...specific responses and regulate growth-defense tradeoffs. To counteract, pathogens have evolved various strategies to disturb hormonal homeostasis and facilitate infection. Many pathogens synthesize plant hormones; more importantly, toxins and effectors are produced to manipulate hormonal crosstalk. Accumulating evidence has shown that pathogens exert extensive effects on plant hormone pathways not only to defeat immunity, but also modify habitat structure, optimize nutrient acquisition, and facilitate pathogen dissemination. In this review, we summarize mechanisms by which a wide array of pathogens gain benefits from manipulating plant hormone pathways.
Twofold CH functionalization of aromatic sulfonic acids was achieved with an in situ generated ruthenium(II) catalyst. The optimized cross‐dehydrogenative alkenylation protocol proved applicable to ...differently substituted arenes and a variety of alkenes, including vinyl arenes, sulfones, nitriles and ketones. The robustness of the ruthenium(II) catalyst was demonstrated by the chemoselective oxidative olefination of sulfonamides as well as sulfonyl chlorides. Mechanistic studies provided support for a reversible, acetate‐assisted CH ruthenation, along with a subsequent olefin insertion.
Versatile oxidative alkenylations of sulfonic acids, sulfonyl chlorides or sulfonamides were achieved by a robust ruthenium(II) catalyst with excellent substrate scope. Mechanistic studies suggested a reversible, acetate‐assisted CH ruthenation, along with a subsequent olefin insertion.
Gram-negative bacterial pathogens rely on the type III secretion system to inject virulence proteins into host cells. These type III secreted "effector" proteins directly manipulate cellular ...processes to cause disease. Although the effector repertoires in different bacterial species are highly variable, the Yersinia outer protein J (YopJ) effector family is unique in that its members are produced by diverse animal and plant pathogens as well as a nonpathogenic microsymbiont. All YopJ family effectors share a conserved catalytic triad that is identical to that of the C55 family of cysteine proteases. However, an accumulating body of evidence demonstrates that many YopJ effectors modify their target proteins in hosts by acetylating specific serine, threonine, and/or lysine residues. This unique acetyltransferase activity allows the YopJ family effectors to affect the function and/or stability of their targets, thereby dampening innate immunity. Here, we summarize the current understanding of this prevalent and evolutionarily conserved type III effector family by describing their enzymatic activities and virulence functions in animals and plants. In particular, the molecular mechanisms by which representative YopJ family effectors subvert host immunity through posttranslational modification of their target proteins are discussed.
A broad range of parasites rely on the functions of effector proteins to subvert host immune response and facilitate disease development. The notorious Phytophthora pathogens evolved effectors with ...RNA silencing suppression activity to promote infection in plant hosts. Here we report that the Phytophthora Suppressor of RNA Silencing 1 (PSR1) can bind to an evolutionarily conserved nuclear protein containing the aspartate-glutamate-alanine-histidine-box RNA helicase domain in plants. This protein, designated PSR1-Interacting Protein 1 (PINP1), regulates the accumulation of both microRNAs and endogenous small interfering RNAs in Arabidopsis. A null mutation of PINP1 causes embryonic lethality, and silencing of PINP1 leads to developmental defects and hypersusceptibility to Phytophthora infection. These phenotypes are reminiscent of transgenic plants expressing PSR1, supporting PINP1 as a direct virulence target of PSR1. We further demonstrate that the localization of the Dicer-like 1 protein complex is impaired in the nucleus of PINP1-silenced or PSR1-expressing cells, indicating that PINP1 may facilitate small RNA processing by affecting the assembly of dicing complexes. A similar function of PINP1 homologous genes in development and immunity was also observed in Nicotiana benthamiana. These findings highlight PINP1 as a previously unidentified component of RNA silencing that regulates distinct classes of small RNAs in plants. Importantly, Phytophthora has evolved effectors to target PINP1 in order to promote infection.
Environmental friendly metal halides have become emerging candidates as energy downconverting emitters for lighting and X‐ray imaging applications. Herein, luminescent single crystals of ...tetramethylammonium manganese chloride (C4H12NMnCl3) and tetraethylammonium bromide ((C8H20N)2MnBr4) are synthesized via a facile room‐temperature evaporation method. C4H12NMnCl3 and (C8H20N)2MnBr4 with octahedrally and tetrahedrally coordinated Mn2+ have correspondingly exhibited red and green emission peaking at 635 and 515 nm both originating from 4T1–6A1 transition of Mn2+ with high photoluminescence quantum yield (PLQY) of 91.8% and 85.1% benefiting from their specific crystal structures. Thanks to their strong photoexcitation under blue light, high PLQY, tunable emission spectra, good environmental stability, the white light‐emitting diode based on blending of C4H12NMnCl3 and (C8H20N)2MnBr4 delivers an outstanding luminous efficacy of 96 lm W−1, approaching commercial level, and shows no obvious photoluminescence intensity degradation after 3000 h under operation. In addition, manganese halides also demonstrate interesting characteristics under X‐ray excitation, C4H12NMnCl3 and (C8H20N)2MnBr4 exhibit steady‐state X‐ray light yields of 50 500 and 24 400 photons MeV−1, low detectable limits of 36.9 and 24.2 nGyair s−1, good radiation hardness, and X‐ray imaging demonstration with high‐resolution of 5 lp mm−1. This work presents a new avenue for luminescent Mn‐based metal halides toward multifunctional light‐emitting applications.
Manganese halides C4H12NMnCl3 and (C8H20N)2MnBr4 have correspondingly exhibited red and green emission with high photoluminescence quantum yields over 85%. The white light‐emitting diode based on their mixture delivers a high luminous efficacy of 96 lm W−1 and 3000 h operational stability. Meanwhile, they exhibit high steady‐state X‐ray light yields of 50 500 and 24 400 photons MeV−1 as well as low detectable limits.
Halide perovskite (HP) nanocrystals (NCs) have recently shown great potential for X-ray detection and imaging. However, the practical application still has a long way to go with many technical ...requirements waiting to be fulfilled, including structure optimization, stability enhancement, and cost reduction. A design principle in this beginning stage is urgently needed but still lacking. Herein, with an “emitter-in-matrix” principle refined from commercial scintillators, CsPbBr3@Cs4PbBr6 with emissive CsPbBr3 NCs embedded inside a solid-state Cs4PbBr6 host is subjected to X-ray sensing and imaging. The Cs4PbBr6 matrix not only enhances the attenuation of X-rays but also dramatically improves the stability of CsPbBr3 NCs. A favorable optical design with the Cs4PbBr6 matrix being transparent to the emission from CsPbBr3 NCs enables efficient light output. As a result, stable and sensitive scintillation response to X-ray signals is demonstrated with superior linearity and ultrahigh time resolution. In order to show the huge potential for practical applications, X-ray imaging using a large-area film (360 mm × 240 mm) by the blade-coating technique is carried out to obtain a high-quality image of interior structures invisible to the human eye. In addition to the above advantages in optics, CsPbBr3@Cs4PbBr6 also enjoys facile solution synthesis with large scalability, excellent repeatability, and low cost.
Cationic ruthenium(II) complexes enabled catalytic twofold C–H bond functionalizations with weakly coordinating aromatic esters in a highly chemo-, site- and diastereo-selective as well as site ...selective fashion. The oxidative Fujiwara–Moritani-type alkenylation provided step-economical access to diversely substituted styrenes and proved viable in an aerobic manner. Mechanistic studies were indicative of a reversible acetate-assisted cycloruthenation step.
X-ray detection, which plays an important role in medical and industrial fields, usually relies on inorganic scintillators to convert X-rays to visible photons; although several high-quantum-yield ...fluorescent molecules have been tested as scintillators, they are generally less efficient. High-energy radiation can ionize molecules and create secondary electrons and ions. As a result, a high fraction of triplet states is generated, which act as scintillation loss channels. Here we found that X-ray-induced triplet excitons can be exploited for emission through very rapid, thermally activated up-conversion. We report scintillators based on three thermally activated delayed fluorescence molecules with different emission bands, which showed significantly higher efficiency than conventional anthracene-based scintillators. X-ray imaging with 16.6 line pairs mm
resolution was also demonstrated. These results highlight the importance of efficient and prompt harvesting of triplet excitons for efficient X-ray scintillation and radiation detection.
Multiple step saccades (MSSs) are an atypical form of saccade that consists of a series of small-amplitude saccades. It has been argued that the mechanism for generating MSS is due to the automatic ...saccadic plan. This argument was based on the observation that trials with MSS had shorter saccadic latency than trials without MSS in the reactive saccades. However, the validity of this argument has never been verified by other saccadic tasks. Alternatively, we and other researchers have speculated that the function of MSS is the same as that of the corrective saccade (CS), i.e., to correct saccadic errors. Thus, we propose that the function of the MSS is also to rectify saccadic errors and generated by forward internal models. The objective of the present study is to examine whether the automatic theory is universally applicable for the generation of MSSs in various saccadic tasks and to seek other possible mechanisms, such as error correction by forward internal models.
Fifty young healthy subjects (YHSs) and fifty elderly healthy subjects (EHSs) were recruited in the present study. The task paradigms were prosaccade (PS), anti-saccade (AS) and memory-guided saccade (MGS) tasks.
Saccadic latency in trials with MSS was shorter than without MSS in the PS task but similar in the AS and MGS tasks. The intersaccadic intervals (ISI) were similar among the three tasks in both YHSs and EHSs.
Our results indicate that the automatic theory is not a universal mechanism. Instead, the forward internal model for saccadic error correction might be an important mechanism.
Inexpensive cobalt‐catalyzed oxidative C−H functionalization has emerged as a powerful tool for the construction of C−C and C−Het bonds, which offers unique potential for transformative applications ...to modern organic synthesis. In the early stage, these transformations typically required stoichiometric and toxic transition metals as sacrificial oxidants; thus, the formation of metal‐containing waste was inevitable. In contrast, naturally abundant molecular O2 has more recently been successfully employed as a green oxidant in cobalt catalysis, thus considerably improving the sustainability of such transformations. Recently, a significant momentum was gained by the use of electricity as a sustainable and environmentally benign redox reagent in cobalt‐catalyzed C−H functionalization, thereby preventing the consumption of cost‐intensive chemicals while at the same time addressing the considerable safety hazards related to the use of molecular oxygen in combination with flammable organic solvents. Considering the unparalleled potential of the aforementioned approaches for sustainable green synthesis, this Review summarizes the recent progress in cobalt‐catalyzed oxidative C−H activation until early 2020.
Metal‐catalyzed C−H activation has emerged as an increasingly powerful tool for molecular synthesis, with major advances achieved by using Earth‐abundant cobalt catalysts. Recent momentum was gained by oxidative C−H transformations, prominently featuring aerobic and electrochemical approaches. Herein, the findings in this topical area of sustainable synthesis are summarized and critically discussed.
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