scholarly journals The Bicarbonate Transporter (MoAE4) Localized on Both Cytomembrane and Tonoplast Promotes Pathogenesis in Magnaporthe oryzae

2021 ◽  
Vol 7 (11) ◽  
pp. 955
Author(s):  
Yuejia Dang ◽  
Yi Wei ◽  
Penghui Zhang ◽  
Xinchun Liu ◽  
Xinrui Li ◽  
...  

Bicarbonate (HCO3−) transporter family including the anion exchanger (AE) group is involved in multiple physiological processes through regulating acid-base homeostasis. HCO3− transporters have been extensively studied in mammals, but fungal homologues of AE are poorly understood. Here, we characterized the AE group member (MoAE4) in Magnaporthe oryzae. MoAE4 exhibits more sequence and structure homologies with the reported AE4 and BOR1 proteins. In addition to the common sublocalization on cytomembrane, MoAE4 also localizes on tonoplast. Yeast complementation verified that MoAE4 rescues boron sensitivity and endows NaHCO3 tolerance in the BOR1 deleted yeast. MoAE4 gene is bicarbonate induced in M. oryzae; and loss of MoAE4 (ΔMoAE4) resulted in mycelial growth inhibited by NaHCO3. Lucigenin fluorescence quenching assay confirmed that ΔMoAE4 accumulated less HCO3− in vacuole and more HCO3− in cytosol, revealing a real role of MoAE4 in bicarbonate transport. ΔMoAE4 was defective in conidiation, appressorium formation, and pathogenicity. More H2O2 was detected to be accumulated in ΔMoAE4 mycelia and infected rice cells. Summarily, our data delineate a cytomembrane and tonoplast located HCO3− transporter, which is required for development and pathogenicity in M. oryzae, and revealing a potential drug target for blast disease control.

2020 ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  

ABSTRACTRice blast disease caused by Magnaporthe oryzae is a devastating disease of cultivated rice worldwide. Infections by this fungus lead to a significant reduction in rice yields and threats to food security. To gain better insight into growth and cell death in M. oryzae during infection, we characterized two predicted M. oryzae metacaspase proteins, MoMca1 and MoMca2. These proteins appear to be functionally redundant and are able to complement the yeast Yca1 homologue. Biochemical analysis revealed that M. oryzae metacaspases exhibited Ca2+ dependent caspase activity in vitro. Deletion of both MoMca1 and MoMca2 in M. oryzae resulted in reduced sporulation, delay in conidial germination and attenuation of disease severity. In addition, the double ΔMomca1mca2 mutant strain showed increased radial growth in the presence of oxidative stress. Interestingly, the ΔMomca1mca2 strain showed an increase accumulation of insoluble aggregates compared to the wild-type strain during vegetative growth. Our findings suggest that MoMca1 and MoMca2 promote the clearance of insoluble aggregates in M. oryzae, demonstrating the important role these metacaspases have in fungal protein homeostasis. Furthermore, these metacaspase proteins may play additional roles, like in regulating stress responses, that would help maintain the fitness of fungal cells required for host infection.IMPORTANCEMagnaporthe oryzae causes rice blast disease that threatens global food security by resulting in the severe loss of rice production every year. A tightly regulated life cycle allows M. oryzae to disarm the host plant immune system during its biotrophic stage before triggering plant cell death in its necrotrophic stage. The ways M. oryzae navigates its complex life cycle remains unclear. This work characterizes two metacaspase proteins with peptidase activity in M. oryzae that are shown to be involved in the regulation of fungal growth and development prior to infection by potentially helping maintain fungal fitness. This study provides new insight into the role of metacaspase proteins in filamentous fungi by illustrating the delays in M. oryzae morphogenesis in the absence of these proteins. Understanding the mechanisms by which M. oryzae morphology and development promote its devastating pathogenicity may lead to the emergence of proper methods for disease control.


mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  

ABSTRACT Rice blast disease caused by Magnaporthe oryzae is a devastating disease of cultivated rice worldwide. Infections by this fungus lead to a significant reduction in rice yields and threats to food security. To gain better insight into growth and cell death in M. oryzae during infection, we characterized two predicted M. oryzae metacaspase proteins, MoMca1 and MoMca2. These proteins appear to be functionally redundant and can complement the yeast Yca1 homologue. Biochemical analysis revealed that M. oryzae metacaspases exhibited Ca2+-dependent caspase activity in vitro. Deletion of both MoMca1 and MoMca2 in M. oryzae resulted in reduced sporulation, delay in conidial germination, and attenuation of disease severity. In addition, the double ΔMomca1mca2 mutant strain showed increased radial growth in the presence of oxidative stress. Interestingly, the ΔMomca1mca2 strain showed an increased accumulation of insoluble aggregates compared to the wild-type strain during vegetative growth. Our findings suggest that MoMca1 and MoMca2 promote the clearance of insoluble aggregates in M. oryzae, demonstrating the important role these metacaspases have in fungal protein homeostasis. Furthermore, these metacaspase proteins may play additional roles, like in regulating stress responses, that would help maintain the fitness of fungal cells required for host infection. IMPORTANCE Magnaporthe oryzae causes rice blast disease that threatens global food security by resulting in the severe loss of rice production every year. A tightly regulated life cycle allows M. oryzae to disarm the host plant immune system during its biotrophic stage before triggering plant cell death in its necrotrophic stage. The ways M. oryzae navigates its complex life cycle remain unclear. This work characterizes two metacaspase proteins with peptidase activity in M. oryzae that are shown to be involved in the regulation of fungal growth and development prior to infection by potentially helping maintain fungal fitness. This study provides new insights into the role of metacaspase proteins in filamentous fungi by illustrating the delays in M. oryzae morphogenesis in the absence of these proteins. Understanding the mechanisms by which M. oryzae morphology and development promote its devastating pathogenicity may lead to the emergence of proper methods for disease control.


2006 ◽  
Vol 34 (5) ◽  
pp. 913-918 ◽  
Author(s):  
N.L. Thomas ◽  
C.H. George ◽  
F.A. Lai

The RyR (ryanodine receptor) mediates rapid Ca2+ efflux from the ER (endoplasmic reticulum) and is responsible for triggering numerous Ca2+-activated physiological processes. The most studied RyR-mediated process is excitation–contraction coupling in striated muscle, where plasma membrane excitation is transmitted to the cell interior and results in Ca2+ efflux that triggers myocyte contraction. Recently, single-residue mutations in the cardiac RyR (RyR2) have been identified in families that exhibit CPVT (catecholaminergic polymorphic ventricular tachycardia), a condition in which physical or emotional stress can trigger severe tachyarrhythmias that can lead to sudden cardiac death. The RyR2 mutations in CPVT are clustered in the N- and C-terminal domains, as well as in a central domain. Further, a critical signalling role for dysfunctional RyR2 has also been implicated in the generation of arrhythmias in the common condition of HF (heart failure). We have prepared cardiac RyR2 plasmids with various CPVT mutations to enable expression and analysis of Ca2+ release mediated by the wild-type and mutated RyR2. These studies suggest that the mutational locus may be important in the mechanism of Ca2+ channel dysfunction. Understanding the causes of aberrant Ca2+ release via RyR2 may assist in the development of effective treatments for the ventricular arrhythmias that often leads to sudden death in HF and in CPVT.


2002 ◽  
Vol 80 (5) ◽  
pp. 579-596 ◽  
Author(s):  
Richard D Vaughan-Jones ◽  
Kenneth W Spitzer

Bicarbonate is important for pHi control in cardiac cells. It is a major part of the intracellular buffer apparatus, it is a substrate for sarcolemmal acid-equivalent transporters that regulate intracellular pH, and it contributes to the pHo sensitivity of steady-state pHi, a phenomenon that may form part of a whole-body response to acid/base disturbances. Both bicarbonate and H+/OH– transporters participate in the sarcolemmal regulation of pHi, namely Na+–HCO3– cotransport (NBC), Cl––HCO3– exchange (i.e., anion exchange, AE), Na+–H+ exchange (NHE), and Cl––OH– exchange (CHE). These transporters are coupled functionally through changes of pHi, while pHi is linked to [Ca2+]i through secondary changes in [Na+]i mediated by NBC and NHE. Via such coupling, decreases of pHo and pHi can ultimately lead to an elevation of [Ca2+]i, thereby influencing cardiac contractility and electrical rhythm. Bicarbonate is also an essential component of an intracellular carbonic buffer shuttle that diffusively couples cytoplasmic pH to the sarcolemma and minimises the formation of intracellular pH microdomains. The importance of bicarbonate is closely linked to the activity of the enzyme carbonic anhydrase (CA). Without CA activity, intracellular bicarbonate-dependent buffering, membrane bicarbonate transport, and the carbonic shuttle are severely compromised. There is a functional partnership between CA and HCO3– transport. Based on our observations on intracellular acid mobility, we propose that one physiological role for CA is to act as a pH-coupling protein, linking bulk pH to the allosteric H+ control sites on sarcolemmal acid/base transporters.Key words: bicarbonate transporter, pHi, heart, ventricular.


2017 ◽  
pp. 98-134 ◽  
Author(s):  
J. Tirole

In the fourth chapter of the book “The economy of the common good”, the nature of economics as a science and research practices in their theoretical and empirical aspects are discussed. The author considers the processes of modeling, empirical verification of models and evaluation of research quality. In addition, the features of economic cognition and the role of mathematics in economic research are analyzed, including the example of relevant research in game theory and information theory.


2015 ◽  
Vol 31 (2) ◽  
pp. 215-240
Author(s):  
Eran Laish

This article focuses on the main contemplative principles of the ‘Heart Essence’ (sNying thig), a Tibetan Buddhist tradition that is characterized by a vision of non-duality and primordial wholeness. Due to this vision, which asserts an original reality that is not divided into perceiving subject and perceived object, the ‘Heart Essence’ advocates a contemplative practice that undermines the usual intuitions of temporality and enclosed selfhood. Hence, unlike the common principles of intentional praxis, such as deliberate concentration and gradual purification, the ‘Heart Essence’ affirms four contemplative principles of non-objectiveness, openness, spontaneity and singleness. As these principles transcend intentionality, temporality, and multiplicity, they are seen to directly disclose the nature of primordial awareness, in which the meanings of knowing and being are radically transformed. Therefore, the article will also consider the role of these non-dual contemplative principles in deeply changing our understanding of being and knowing alike.


2020 ◽  
Vol 2020 (10-3) ◽  
pp. 70-81
Author(s):  
David Ramiro Troitino ◽  
Tanel Kerikmae ◽  
Olga Shumilo

This article highlights the role of Charles de Gaulle in the history of united post-war Europe, his approaches to the internal and foreign French policies, also vetoing the membership of the United Kingdom in the European Community. The authors describe the emergence of De Gaulle as a politician, his uneasy relationship with Roosevelt and Churchill during World War II, also the roots of developing a “nationalistic” approach to regional policy after the end of the war. The article also considers the emergence of the Common Agricultural Policy (hereinafter - CAP), one of Charles de Gaulle’s biggest achievements in foreign policy, and the reasons for the Fouchet Plan defeat.


2019 ◽  
pp. 512-519
Author(s):  
Teymur Dzhalilov ◽  
Nikita Pivovarov

The published document is a part of the working record of The Secretariat of the CPSU Central Committee on May 5, 1969. The employees of The Common Department of the CPSU Central Committee started writing such working records from the end of 1965. In contrast to the protocols, the working notes include speeches of the secretaries of the Central Committee, that allow to deeper analyze the reactions of the top party leadership, to understand their position regarding the political agenda. The peculiarity of the published document is that the Secretariat of the Central Committee did not deal with the most important foreign policy issues. It was the responsibility of the Politburo. However, it was at a meeting of the Secretariat of the Central Committee when Brezhnev raised the question of inviting G. Husák to Moscow. The latter replaced A. Dubček as the first Secretary of the Communist party of Czechoslovakia in April 1969. As follows from the document, Leonid Brezhnev tried to solve this issue at a meeting of the Politburo, but failed. However, even at the Secretariat of the Central Committee the Leonid Brezhnev’s initiative at the invitation of G. Husák was not supported. The published document reveals to us not only new facets in the mechanisms of decision-making in the CPSU Central Committee, the role of the Secretary General in this process, but also reflects the acute discussions within the Soviet government about the future of the world socialist systems.


2020 ◽  
Author(s):  
Igor Grossmann ◽  
Nic M. Weststrate ◽  
Monika Ardelt ◽  
Justin Peter Brienza ◽  
Mengxi Dong ◽  
...  

Interest in wisdom in the cognitive sciences, psychology, and education has been paralleled by conceptual confusions about its nature and assessment. To clarify these issues and promote consensus in the field, wisdom researchers met in Toronto in July of 2019, resolving disputes through discussion. Guided by a survey of scientists who study wisdom-related constructs, we established a common wisdom model, observing that empirical approaches to wisdom converge on the morally-grounded application of metacognition to reasoning and problem-solving. After outlining the function of relevant metacognitive and moral processes, we critically evaluate existing empirical approaches to measurement and offer recommendations for best practices. In the subsequent sections, we use the common wisdom model to selectively review evidence about the role of individual differences for development and manifestation of wisdom, approaches to wisdom development and training, as well as cultural, subcultural, and social-contextual differences. We conclude by discussing wisdom’s conceptual overlap with a host of other constructs and outline unresolved conceptual and methodological challenges.


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