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1.
Cell ; 187(10): 2557-2573.e18, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38729111

RESUMEN

Many of the world's most devastating crop diseases are caused by fungal pathogens that elaborate specialized infection structures to invade plant tissue. Here, we present a quantitative mass-spectrometry-based phosphoproteomic analysis of infection-related development by the rice blast fungus Magnaporthe oryzae, which threatens global food security. We mapped 8,005 phosphosites on 2,062 fungal proteins following germination on a hydrophobic surface, revealing major re-wiring of phosphorylation-based signaling cascades during appressorium development. Comparing phosphosite conservation across 41 fungal species reveals phosphorylation signatures specifically associated with biotrophic and hemibiotrophic fungal infection. We then used parallel reaction monitoring (PRM) to identify phosphoproteins regulated by the fungal Pmk1 MAPK that controls plant infection by M. oryzae. We define 32 substrates of Pmk1 and show that Pmk1-dependent phosphorylation of regulator Vts1 is required for rice blast disease. Defining the phosphorylation landscape of infection therefore identifies potential therapeutic interventions for the control of plant diseases.


Asunto(s)
Proteínas Fúngicas , Oryza , Enfermedades de las Plantas , Fosforilación , Oryza/microbiología , Oryza/metabolismo , Enfermedades de las Plantas/microbiología , Proteínas Fúngicas/metabolismo , Fosfoproteínas/metabolismo , Ascomicetos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteómica , Transducción de Señal
2.
Proc Natl Acad Sci U S A ; 121(24): e2218927121, 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38830094

RESUMEN

Oomycete protists share phenotypic similarities with fungi, including the ability to cause plant diseases, but branch in a distant region of the tree of life. It has been suggested that multiple horizontal gene transfers (HGTs) from fungi-to-oomycetes contributed to the evolution of plant-pathogenic traits. These HGTs are predicted to include secreted proteins that degrade plant cell walls, a barrier to pathogen invasion and a rich source of carbohydrates. Using a combination of phylogenomics and functional assays, we investigate the diversification of a horizontally transferred xyloglucanase gene family in the model oomycete species Phytophthora sojae. Our analyses detect 11 xyloglucanase paralogs retained in P. sojae. Using heterologous expression in yeast, we show consistent evidence that eight of these paralogs have xyloglucanase function, including variants with distinct protein characteristics, such as a long-disordered C-terminal extension that can increase xyloglucanase activity. The functional variants analyzed subtend a phylogenetic node close to the fungi-to-oomycete transfer, suggesting the horizontally transferred gene was a bona fide xyloglucanase. Expression of three xyloglucanase paralogs in Nicotiana benthamiana triggers high-reactive oxygen species (ROS) generation, while others inhibit ROS responses to bacterial immunogens, demonstrating that the paralogs differentially stimulate pattern-triggered immunity. Mass spectrometry of detectable enzymatic products demonstrates that some paralogs catalyze the production of variant breakdown profiles, suggesting that secretion of variant xyloglucanases increases efficiency of xyloglucan breakdown as well as diversifying the damage-associated molecular patterns released. We suggest that this pattern of neofunctionalization and the variant host responses represent an aspect of the Red Queen host-pathogen coevolutionary dynamic.


Asunto(s)
Transferencia de Gen Horizontal , Glicósido Hidrolasas , Filogenia , Glicósido Hidrolasas/metabolismo , Glicósido Hidrolasas/genética , Phytophthora/patogenicidad , Phytophthora/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/parasitología , Evolución Molecular , Duplicación de Gen
3.
Am J Hum Genet ; 110(7): 1162-1176, 2023 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-37352861

RESUMEN

Large-scale genetic association studies have identified multiple susceptibility loci for nasopharyngeal carcinoma (NPC), but the underlying biological mechanisms remain to be explored. To gain insights into the genetic etiology of NPC, we conducted a follow-up study encompassing 6,907 cases and 10,472 controls and identified two additional NPC susceptibility loci, 9q22.33 (rs1867277; OR = 0.74, 95% CI = 0.68-0.81, p = 3.08 × 10-11) and 17q12 (rs226241; OR = 1.42, 95% CI = 1.26-1.60, p = 1.62 × 10-8). The two additional loci, together with two previously reported genome-wide significant loci, 5p15.33 and 9p21.3, were investigated by high-throughput sequencing for chromatin accessibility, histone modification, and promoter capture Hi-C (PCHi-C) profiling. Using luciferase reporter assays and CRISPR interference (CRISPRi) to validate the functional profiling, we identified PHF2 at locus 9q22.33 as a susceptibility gene. PHF2 encodes a histone demethylase and acts as a tumor suppressor. The risk alleles of the functional SNPs reduced the expression of the target gene PHF2 by inhibiting the enhancer activity of its long-range (4.3 Mb) cis-regulatory element, which promoted proliferation of NPC cells. In addition, we identified CDKN2B-AS1 as a susceptibility gene at locus 9p21.3, and the NPC risk allele of the functional SNP rs2069418 promoted the expression of CDKN2B-AS1 by increasing its enhancer activity. The overexpression of CDKN2B-AS1 facilitated proliferation of NPC cells. In summary, we identified functional SNPs and NPC susceptibility genes, which provides additional explanations for the genetic association signals and helps to uncover the underlying genetic etiology of NPC development.


Asunto(s)
Neoplasias Nasofaríngeas , Humanos , Carcinoma Nasofaríngeo/genética , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/patología , Estudios de Seguimiento , Predisposición Genética a la Enfermedad , Estudios de Asociación Genética , Polimorfismo de Nucleótido Simple/genética , Proteínas de Homeodominio/genética
4.
PLoS Pathog ; 20(6): e1012277, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38885263

RESUMEN

Filamentous plant pathogens deliver effector proteins into host cells to suppress host defence responses and manipulate metabolic processes to support colonization. Understanding the evolution and molecular function of these effectors provides knowledge about pathogenesis and can suggest novel strategies to reduce damage caused by pathogens. However, effector proteins are highly variable, share weak sequence similarity and, although they can be grouped according to their structure, only a few structurally conserved effector families have been functionally characterized to date. Here, we demonstrate that Zinc-finger fold (ZiF) secreted proteins form a functionally diverse effector family in the blast fungus Magnaporthe oryzae. This family relies on the Zinc-finger motif for protein stability and is ubiquitously present in blast fungus lineages infecting 13 different host species, forming different effector tribes. Homologs of the canonical ZiF effector, AVR-Pii, from rice infecting isolates are present in multiple M. oryzae lineages. Wheat infecting strains of the fungus also possess an AVR-Pii like allele that binds host Exo70 proteins and activates the immune receptor Pii. Furthermore, ZiF tribes may vary in the proteins they bind to, indicating functional diversification and an intricate effector/host interactome. Altogether, we uncovered a new effector family with a common protein fold that has functionally diversified in lineages of M. oryzae. This work expands our understanding of the diversity of M. oryzae effectors, the molecular basis of plant pathogenesis and may ultimately facilitate the development of new sources for pathogen resistance.

5.
Plant Cell ; 35(5): 1360-1385, 2023 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-36808541

RESUMEN

The rice blast fungus Magnaporthe oryzae causes a devastating disease that threatens global rice (Oryza sativa) production. Despite intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high-resolution transcriptional profiling study of the entire plant-associated development of the blast fungus. Our analysis revealed major temporal changes in fungal gene expression during plant infection. Pathogen gene expression could be classified into 10 modules of temporally co-expressed genes, providing evidence for the induction of pronounced shifts in primary and secondary metabolism, cell signaling, and transcriptional regulation. A set of 863 genes encoding secreted proteins are differentially expressed at specific stages of infection, and 546 genes named MEP (Magnaportheeffector protein) genes were predicted to encode effectors. Computational prediction of structurally related MEPs, including the MAX effector family, revealed their temporal co-regulation in the same co-expression modules. We characterized 32 MEP genes and demonstrate that Mep effectors are predominantly targeted to the cytoplasm of rice cells via the biotrophic interfacial complex and use a common unconventional secretory pathway. Taken together, our study reveals major changes in gene expression associated with blast disease and identifies a diverse repertoire of effectors critical for successful infection.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Magnaporthe/fisiología , Ascomicetos/metabolismo , Transducción de Señal , Citoplasma/metabolismo , Oryza/metabolismo , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
6.
Plant Cell ; 35(5): 1386-1407, 2023 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-36748203

RESUMEN

Plants undergo extended morphogenesis. The shoot apical meristem (SAM) allows for reiterative development and the formation of new structures throughout the life of the plant. Intriguingly, the SAM produces morphologically different leaves in an age-dependent manner, a phenomenon known as heteroblasty. In Arabidopsis thaliana, the SAM produces small orbicular leaves in the juvenile phase, but gives rise to large elliptical leaves in the adult phase. Previous studies have established that a developmental decline of microRNA156 (miR156) is necessary and sufficient to trigger this leaf shape switch, although the underlying mechanism is poorly understood. Here we show that the gradual increase in miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE transcription factors with age promotes cell growth anisotropy in the abaxial epidermis at the base of the leaf blade, evident by the formation of elongated giant cells. Time-lapse imaging and developmental genetics further revealed that the establishment of adult leaf shape is tightly associated with the longitudinal cell expansion of giant cells, accompanied by a prolonged cell proliferation phase in their vicinity. Our results thus provide a plausible cellular mechanism for heteroblasty in Arabidopsis, and contribute to our understanding of anisotropic growth in plants.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , MicroARNs , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Factores de Transcripción/metabolismo , Hojas de la Planta/metabolismo , Meristema/genética , Meristema/metabolismo , Proliferación Celular/genética , Regulación de la Expresión Génica de las Plantas/genética , MicroARNs/genética , MicroARNs/metabolismo
7.
Proc Natl Acad Sci U S A ; 120(8): e2215426120, 2023 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-36791100

RESUMEN

Blast disease in cereal plants is caused by the fungus Magnaporthe oryzae and accounts for a significant loss in food crops. At the outset of infection, expression of a putative polysaccharide monooxygenase (MoPMO9A) is increased. MoPMO9A contains a catalytic domain predicted to act on cellulose and a carbohydrate-binding domain that binds chitin. A sequence similarity network of the MoPMO9A family AA9 showed that 220 of the 223 sequences in the MoPMO9A-containing cluster of sequences have a conserved unannotated region with no assigned function. Expression and purification of the full length and two MoPMO9A truncations, one containing the catalytic domain and the domain of unknown function (DUF) and one with only the catalytic domain, were carried out. In contrast to other AA9 polysaccharide monooxygenases (PMOs), MoPMO9A is not active on cellulose but showed activity on cereal-derived mixed (1→3, 1→4)-ß-D-glucans (MBG). Moreover, the DUF is required for activity. MoPMO9A exhibits activity consistent with C4 oxidation of the polysaccharide and can utilize either oxygen or hydrogen peroxide as a cosubstrate. It contains a predicted 3-dimensional fold characteristic of other PMOs. The DUF is predicted to form a coiled-coil with six absolutely conserved cysteines acting as a zipper between the two α-helices. MoPMO9A substrate specificity and domain architecture are different from previously characterized AA9 PMOs. The results, including a gene ontology analysis, support a role for MoPMO9A in MBG degradation during plant infection. Consistent with this analysis, deletion of MoPMO9A results in reduced pathogenicity.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Oxigenasas de Función Mixta/metabolismo , Polisacáridos/metabolismo , Celulosa/metabolismo , Ascomicetos/metabolismo , Magnaporthe/genética , Enfermedades de las Plantas/microbiología , Proteínas Fúngicas/metabolismo , Oryza/metabolismo
8.
Proc Natl Acad Sci U S A ; 120(12): e2301358120, 2023 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-36913579

RESUMEN

To cause rice blast disease, the filamentous fungus Magnaporthe oryzae secretes a battery of effector proteins into host plant tissue to facilitate infection. Effector-encoding genes are expressed only during plant infection and show very low expression during other developmental stages. How effector gene expression is regulated in such a precise manner during invasive growth by M. oryzae is not known. Here, we report a forward-genetic screen to identify regulators of effector gene expression, based on the selection of mutants that show constitutive effector gene expression. Using this simple screen, we identify Rgs1, a regulator of G-protein signaling (RGS) protein that is necessary for appressorium development, as a novel transcriptional regulator of effector gene expression, which acts prior to plant infection. We show that an N-terminal domain of Rgs1, possessing transactivation activity, is required for effector gene regulation and acts in an RGS-independent manner. Rgs1 controls the expression of at least 60 temporally coregulated effector genes, preventing their transcription during the prepenetration stage of development prior to plant infection. A regulator of appressorium morphogenesis is therefore also required for the orchestration of pathogen gene expression required for invasive growth by M. oryzae during plant infection.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Magnaporthe/genética , Ascomicetos/genética , Transducción de Señal , Expresión Génica , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Oryza/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
9.
Proc Natl Acad Sci U S A ; 120(34): e2302603120, 2023 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-37579161

RESUMEN

Certain transmembrane and membrane-tethered signaling proteins export from cilia as BBSome cargoes via the outward BBSome transition zone (TZ) diffusion pathway, indispensable for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. Murine Rab-like 2 (Rabl2) GTPase resembles Chlamydomonas Arf-like 3 (ARL3) GTPase in promoting outward TZ passage of the signaling protein cargo-laden BBSome. During this process, ARL3 binds to and recruits the retrograde IFT train-dissociated BBSome as its effector to diffuse through the TZ for ciliary retrieval, while how RABL2 and ARL3 cross talk in this event remains uncertain. Here, we report that Chlamydomonas RABL2 in a GTP-bound form (RABL2GTP) cycles through cilia via IFT as an IFT-B1 cargo, dissociates from retrograde IFT trains at a ciliary region right above the TZ, and converts to RABL2GDP for activating ARL3GDP as an ARL3 guanine nucleotide exchange factor. This confers ARL3GTP to detach from the ciliary membrane and become available for binding and recruiting the phospholipase D (PLD)-laden BBSome, autonomous of retrograde IFT association, to diffuse through the TZ for ciliary retrieval. Afterward, RABL2GDP exits cilia by being bound to the ARL3GTP/BBSome entity as a BBSome cargo. Our data identify ciliary signaling proteins exported from cilia via the RABL2-ARL3 cascade-mediated outward BBSome TZ diffusion pathway. According to this model, hedgehog signaling defect-induced Bardet-Biedl syndrome caused by RABL2 mutations in humans could be well explained in a mutation-specific manner, providing us with a mechanistic understanding behind the outward BBSome TZ passage required for proper ciliary signaling.


Asunto(s)
Cilios , Proteínas Hedgehog , Humanos , Factores de Ribosilacion-ADP/genética , Factores de Ribosilacion-ADP/metabolismo , Cilios/metabolismo , GTP Fosfohidrolasas/metabolismo , Guanosina Trifosfato/metabolismo , Proteínas Hedgehog/metabolismo , Proteínas de la Membrana/metabolismo , Transporte de Proteínas/genética , Proteínas de Unión al GTP rab/metabolismo , Chlamydomonas
10.
Proc Natl Acad Sci U S A ; 120(13): e2218819120, 2023 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-36943875

RESUMEN

Certain ciliary transmembrane and membrane-tethered signaling proteins migrate from the ciliary tip to base via retrograde intraflagellar transport (IFT), essential for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. During this process, the BBSome functions as an adaptor between retrograde IFT trains and these signaling protein cargoes. The Arf-like 13 (ARL13) small GTPase resembles ARL6/BBS3 in facilitating these signaling cargoes to couple with the BBSome at the ciliary tip prior to loading onto retrograde IFT trains for transporting towards the ciliary base, while the molecular basis for how this intricate coupling event happens remains elusive. Here, we report that Chlamydomonas ARL13 only in a GTP-bound form (ARL13GTP) anchors to the membrane for diffusing into cilia. Upon entering cilia, ARL13 undergoes GTPase cycle for shuttling between the ciliary membrane (ARL13GTP) and matrix (ARL13GDP). To achieve this goal, the ciliary membrane-anchored BBS3GTP binds the ciliary matrix-residing ARL13GDP to activate the latter as an ARL13 guanine nucleotide exchange factor. At the ciliary tip, ARL13GTP recruits the ciliary matrix-residing and post-remodeled BBSome as an ARL13 effector to anchor to the ciliary membrane. This makes the BBSome spatiotemporally become available for the ciliary membrane-tethered phospholipase D (PLD) to couple with. Afterward, ARL13GTP hydrolyzes GTP for releasing the PLD-laden BBSome to load onto retrograde IFT trains. According to this model, hedgehog signaling defects associated with ARL13b and BBS3 mutations in humans could be satisfactorily explained, providing us a mechanistic understanding behind BBSome-cargo coupling required for proper ciliary signaling.


Asunto(s)
Síndrome de Bardet-Biedl , Cilios , Humanos , Cilios/metabolismo , Transporte de Proteínas/genética , Síndrome de Bardet-Biedl/genética , Proteínas Hedgehog/metabolismo , Proteínas de la Membrana/metabolismo , Guanosina Trifosfato/metabolismo , Flagelos/metabolismo
11.
J Biol Chem ; 300(4): 107123, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38417796

RESUMEN

Thiram is a toxic fungicide extensively used for the management of pathogens in fruits. Although it is known that thiram degrades in plant tissues, the key enzymes involved in this process remain unexplored. In this study, we report that a tau class glutathione S-transferase (GST) from Carica papaya can degrade thiram. This enzyme was easily obtained by heterologous expression in Escherichia coli, showed low promiscuity toward other thiuram disulfides, and catalyzed thiram degradation under physiological reaction conditions. Site-directed mutagenesis indicated that G-site residue S67 shows a key influence for the enzymatic activity toward thiram, while mutation of residue S13, which reduced the GSH oxidase activity, did not significantly affect the thiram-degrading activity. The formation of dimethyl dithiocarbamate, which was subsequently converted into carbon disulfide, and dimethyl dithiocarbamoylsulfenic acid as the thiram degradation products suggested that thiram undergoes an alkaline hydrolysis that involves the rupture of the disulfide bond. Application of the GST selective inhibitor 4-chloro-7-nitro-2,1,3-benzoxadiazole reduced papaya peel thiram-degrading activity by 95%, indicating that this is the main degradation route of thiram in papaya. GST from Carica papaya also catalyzed the degradation of the fungicides chlorothalonil and thiabendazole, with residue S67 showing again a key influence for the enzymatic activity. These results fill an important knowledge gap in understanding the catalytic promiscuity of plant GSTs and reveal new insights into the fate and degradation products of thiram in fruits.


Asunto(s)
Carica , Glutatión Transferasa , Tiram , Carica/enzimología , Carica/genética , Fungicidas Industriales/metabolismo , Glutatión Transferasa/metabolismo , Glutatión Transferasa/genética , Glutatión Transferasa/química , Mutagénesis Sitio-Dirigida , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tiram/metabolismo , Escherichia coli/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
12.
J Pathol ; 262(4): 427-440, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38229567

RESUMEN

Radiotherapy is one of the standard therapeutic regimens for medulloblastoma (MB). Tumor cells utilize DNA damage repair (DDR) mechanisms to survive and develop resistance during radiotherapy. It has been found that targeting DDR sensitizes tumor cells to radiotherapy in several types of cancer, but whether and how DDR pathways are involved in the MB radiotherapy response remain to be determined. Single-cell RNA sequencing was carried out on 38 MB tissues, followed by expression enrichment assays. Fanconi anemia group D2 gene (FANCD2) expression was evaluated in MB samples and public MB databases. The function of FANCD2 in MB cells was examined using cell counting assays (CCK-8), clone formation, lactate dehydrogenase activity, and in mouse orthotopic models. The FANCD2-related signaling pathway was investigated using assays of peroxidation, a malondialdehyde assay, a reduced glutathione assay, and using FerroOrange to assess intracellular iron ions (Fe2+ ). Here, we report that FANCD2 was highly expressed in the malignant sonic hedgehog (SHH) MB subtype (SHH-MB). FANCD2 played an oncogenic role and predicted worse prognosis in SHH-MB patients. Moreover, FANCD2 knockdown markedly suppressed viability, mobility, and growth of SHH-MB cells and sensitized SHH-MB cells to irradiation. Mechanistically, FANCD2 deficiency led to an accumulation of Fe2+ due to increased divalent metal transporter 1 expression and impaired glutathione peroxidase 4 activity, which further activated ferroptosis and reduced proliferation of SHH-MB cells. Using an orthotopic mouse model, we observed that radiotherapy combined with silencing FANCD2 significantly inhibited the growth of SHH-MB cell-derived tumors in vivo. Our study revealed FANCD2 as a potential therapeutic target in SHH-MB and silencing FANCD2 could sensitize SHH-MB cells to radiotherapy via inducing ferroptosis. © 2024 The Pathological Society of Great Britain and Ireland.


Asunto(s)
Neoplasias Cerebelosas , Anemia de Fanconi , Ferroptosis , Meduloblastoma , Ratones , Animales , Humanos , Meduloblastoma/genética , Meduloblastoma/radioterapia , Ferroptosis/genética , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Neoplasias Cerebelosas/genética , Neoplasias Cerebelosas/radioterapia , Línea Celular Tumoral , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética
13.
Nature ; 574(7778): 423-427, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31597961

RESUMEN

The blast fungus Magnaporthe oryzae gains entry to its host plant by means of a specialized pressure-generating infection cell called an appressorium, which physically ruptures the leaf cuticle1,2. Turgor is applied as an enormous invasive force by septin-mediated reorganization of the cytoskeleton and actin-dependent protrusion of a rigid penetration hypha3. However, the molecular mechanisms that regulate the generation of turgor pressure during appressorium-mediated infection of plants remain poorly understood. Here we show that a turgor-sensing histidine-aspartate kinase, Sln1, enables the appressorium to sense when a critical turgor threshold has been reached and thereby facilitates host penetration. We found that the Sln1 sensor localizes to the appressorium pore in a pressure-dependent manner, which is consistent with the predictions of a mathematical model for plant infection. A Δsln1 mutant generates excess intracellular appressorium turgor, produces hyper-melanized non-functional appressoria and does not organize the septins and polarity determinants that are required for leaf infection. Sln1 acts in parallel with the protein kinase C cell-integrity pathway as a regulator of cAMP-dependent signalling by protein kinase A. Pkc1 phosphorylates the NADPH oxidase regulator NoxR and, collectively, these signalling pathways modulate appressorium turgor and trigger the generation of invasive force to cause blast disease.


Asunto(s)
Ascomicetos/metabolismo , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Proteínas Fúngicas/metabolismo , Hifa , NADPH Oxidasas/metabolismo , Oryza/fisiología
14.
J Am Chem Soc ; 146(18): 12485-12495, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38651836

RESUMEN

Understanding the mechanisms of C-H activation of alkanes is a very important research topic. The reactions of metal clusters with alkanes have been extensively studied to reveal the electronic features governing C-H activation, while the experimental cluster reactivity was qualitatively interpreted case by case in the literature. Herein, we prepared and mass-selected over 100 rhodium-based clusters (RhxVyOz- and RhxCoyOz-) to react with light alkanes, enabling the determination of reaction rate constants spanning six orders of magnitude. A satisfactory model being able to quantitatively describe the rate data in terms of multiple cluster electronic features (average electron occupancy of valence s orbitals, the minimum natural charge on the metal atom, cluster polarizability, and energy gap involved in the agostic interaction) has been constructed through a machine learning approach. This study demonstrates that the general mechanisms governing the very important process of C-H activation by diverse metal centers can be discovered by interpreting experimental data with artificial intelligence.

15.
Anal Chem ; 96(1): 67-75, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38153001

RESUMEN

Origins of pH effects on the kinetics of electrocatalytic reactions involving the transfer of both protons and electrons, including the hydrogen evolution reaction (HER) considered in this study, are heatedly debated. By taking the HER at Au(111) in acid solutions of different pHs and ionic concentrations as the model systems, herein, we report how to derive the intrinsic kinetic parameters of such reactions and their pH dependence through the measurement of j-E curves and the corresponding kinetic simulation based on the Frumkin-Butler-Volmer theory and the modified Poisson-Nernst-Planck equation. Our study reveals the following: (i) the same set of kinetic parameters, such as the standard activation Gibbs free energy, charge transfer coefficient, and Gibbs adsorption energy for Had at Au(111), can simulate well all the j-E curves measured in solutions with different pH and temperatures; (ii) on the reversible hydrogen electrode scale, the intrinsic rate constant increases with the increase of pH, which is in contrast with the decrease of the HER current with the increase of pH; and (iii) the ratio of the rate constants for HER at Au(111) in x M HClO4 + (0.1 - x) M NaClO4 (pH ≤ 3) deduced before properly correcting the electric double layer (EDL) effects to the ones estimated with EDL correction is in the range of ca. 10 to 40, and even in a solution of x M HClO4 + (1 - x) M NaClO4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL correction. The importance of proper correction of the EDL effects as well as several other important factors on unveiling the intrinsic pH-dependent reaction kinetics are discussed to help converge our analysis of pH effects in electrocatalysis.

16.
New Phytol ; 241(3): 1007-1020, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38073141

RESUMEN

Rice blast, the most destructive disease of cultivated rice world-wide, is caused by the filamentous fungus Magnaporthe oryzae. To cause disease in plants, M. oryzae secretes a diverse range of effector proteins to suppress plant defense responses, modulate cellular processes, and support pathogen growth. Some effectors can be secreted by appressoria even before host penetration, while others accumulate in the apoplast, or enter living plant cells where they target specific plant subcellular compartments. During plant infection, the blast fungus induces the formation of a specialized plant structure known as the biotrophic interfacial complex (BIC), which appears to be crucial for effector delivery into plant cells. Here, we review recent advances in the cell biology of M. oryzae-host interactions and show how new breakthroughs in disease control have stemmed from an increased understanding of effector proteins of M. oryzae are deployed and delivered into plant cells to enable pathogen invasion and host susceptibility.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Proteínas Fúngicas/metabolismo , Ascomicetos/metabolismo , Transporte Biológico , Oryza/metabolismo , Enfermedades de las Plantas/microbiología
17.
Hepatology ; 2023 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-38015993

RESUMEN

BACKGROUND AND AIMS: Pseudouridine is a prevalent RNA modification and is highly present in the serum and urine of patients with HCC. However, the role of pseudouridylation and its modifiers in HCC remains unknown. We investigated the function and underlying mechanism of pseudouridine synthase 1 (PUS1) in HCC. APPROACH AND RESULTS: By analyzing the TCGA data set, PUS1 was found to be significantly upregulated in human HCC specimens and positively correlated with tumor grade and poor prognosis of HCC. Knockdown of PUS1 inhibited cell proliferation and the growth of tumors in a subcutaneous xenograft mouse model. Accordingly, increased cell proliferation and tumor growth were observed in PUS1-overexpressing cells. Furthermore, overexpression of PUS1 significantly accelerates tumor formation in a mouse HCC model established by hydrodynamic tail vein injection, while knockout of PUS1 decreases it. Additionally, PUS1 catalytic activity is required for HCC tumorigenesis. Mechanistically, we profiled the mRNA targets of PUS1 by utilizing surveying targets by apolipoprotein B mRNA-editing enzyme 1 (APOBEC1)-mediated profiling and found that PUS1 incorporated pseudouridine into mRNAs of a set of oncogenes, thereby endowing them with greater translation capacity. CONCLUSIONS: Our study highlights the critical role of PUS1 and pseudouridylation in HCC development, and provides new insight that PUS1 enhances the protein levels of a set of oncogenes, including insulin receptor substrate 1 (IRS1) and c-MYC, by means of pseudouridylation-mediated mRNA translation.

18.
BMC Cancer ; 24(1): 253, 2024 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-38395798

RESUMEN

BACKGROUND: Cancer cachexia is associated with impaired functional and nutritional status and worse clinical outcomes. Global Leadership Initiative in Malnutrition (GLIM) consensus recommended the application of GLIM criteria to diagnose malnutrition in patients with cachexia. However, few previous study has applied the GLIM criteria in patients with cancer cachexia. METHODS: From July 2014 to May 2019, patients who were diagnosed with cancer cachexia and underwent radical gastrectomy for gastric cancer were included in this study. Malnutrition was diagnosed using the GLIM criteria. Skeletal muscle index was measured using abdominal computed tomography (CT) images at the third lumbar vertebra (L3) level. Hand-grip strength and 6-meters gait speed were measured before surgery. RESULTS: A total of 356 patients with cancer cachexia were included in the present study, in which 269 (75.56%) were identified as having malnutrition based on the GLIM criteria. GLIM-defined malnutrition alone did not show significant association with short-term postoperative outcomes, including complications, costs or length of postoperative hospital stays. The combination of low hand-grip strength or low gait speed with GLIM-defined malnutrition led to a significant predictive value for these outcomes. Moreover, low hand-grip strength plus GLIM-defined malnutrition was independently associated with postoperative complications (OR 1.912, 95% CI 1.151-3.178, P = 0.012). GLIM-defined malnutrition was an independent predictive factor for worse OS (HR 2.310, 95% CI 1.421-3.754, P = 0.001) and DFS (HR 1.815, 95% CI 1.186-2.779, P = 0.006) after surgery. The addition of low hand-grip strength or low gait speed to GLIM-defined malnutrition did not increase its predictive value for survival. CONCLUSION: GLIM-defined malnutrition predicted worse long-term survival in gastric cancer patients with cachexia. Gait speed and hand-grip strength added prognostic value to GLIM-defined malnutrition for the prediction of short-term postoperative outcomes, which could be incorporated into preoperative assessment protocols in patients with cancer cachexia.


Asunto(s)
Desnutrición , Neoplasias Gástricas , Humanos , Caquexia/diagnóstico , Caquexia/etiología , Pronóstico , Neoplasias Gástricas/complicaciones , Neoplasias Gástricas/cirugía , Liderazgo , Velocidad al Caminar , Desnutrición/complicaciones , Desnutrición/diagnóstico , Estado Nutricional , Fuerza de la Mano , Evaluación Nutricional
19.
Malar J ; 23(1): 84, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38500090

RESUMEN

BACKGROUND: Malaria is an infectious malady caused by Plasmodium parasites, cerebral malaria standing out as one of its most severe complications. Clinical manifestation include elevated body temperature, loss of consciousness, and seizures. However, reports of cerebral malaria presenting as nonconvulsive status epilepticus are extremely rare. The case presented involves psychiatric symptoms, with the electroencephalogram indicated nonconvulsive status epilepticus associated with cerebral malaria. CASE PRESENTATION: A 53-year-old male, was urgently admitted, due to confusion and abnormal behaviour for 10 h. The patient returned to China after developing a fever while working in Tanzania two months ago. The blood smear revealed Plasmodium vivax and Plasmodium falciparum, and he was diagnosed with malaria. He recovered following anti-malarial treatment. After admission, the patient was confused, unable to communicate normally, and unwilling to cooperate with the physical examination. Plasmodium was not found in the blood smear, but the DNA sequence of P. falciparum was discovered using metagenomic next-generation sequencing of cerebrospinal fluid. Brain MRI revealed no significant abnormalities. Continuous electroencephalogram monitoring revealed that the patient had non-convulsive status epilepticus, which was treated with diazepam and levetiracetam. The patient had normal consciousness and behaviour. He received anti-malarial treatment for two weeks and fully recovered. CONCLUSIONS: This case demonstrates that nonconvulsive status epilepticus can be a manifestation of cerebral malaria. It is imperative for attending physicians to heighten vigilance when encountering patients with a history of travel to malaria-endemic regions or a prior malaria infection, especially in the presence of unusual clinical presentations.


Asunto(s)
Antimaláricos , Malaria Cerebral , Malaria Falciparum , Plasmodium , Estado Epiléptico , Masculino , Humanos , Persona de Mediana Edad , Malaria Cerebral/complicaciones , Malaria Cerebral/diagnóstico , Malaria Cerebral/tratamiento farmacológico , Antimaláricos/uso terapéutico , Malaria Falciparum/complicaciones , Malaria Falciparum/diagnóstico , Malaria Falciparum/tratamiento farmacológico , Estado Epiléptico/diagnóstico , Estado Epiléptico/tratamiento farmacológico , Estado Epiléptico/etiología
20.
Analyst ; 149(2): 395-402, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38051224

RESUMEN

A europium-functionalized, dual-emissive, metal-organic framework-based fluorescence sensor (EuUCNDA) was constructed via post-synthetic modification of an UiO-66-type precursor through coordination interactions. EuUCNDA exhibited extremely high selectivity and sensitivity for malachite green (MG) with a low detection limit of 13.01 nM, a wide linear concentration range (0.05-50 µM), excellent anti-interference properties, a rapid response (<1 min), and the possibility of recycling. The good sensing performance of EuUCNDA enables the practical detection of MG in fish pond water and grass carp with good recoveries. Moreover, EuUCNDA can be reused for sensing MG and over 90% of fluorescence intensity can be restored after 7 cycles. Furthermore, EuUCNDA-embedded paper-based sensors combined with smartphone imaging afford portable and visual monitoring of MG in real samples. Notably, besides good sensing performance, EuUCNDA could efficiently remove MG from water. Hence, this work provides a recyclable and sensitive fluorescence sensor for portable, visual, rapid detection and efficient removal of MG.

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