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  • In this study we have identified and characterized three

    2020-07-31

    In this study, we have identified and characterized three sunflower ENO isoforms. We surveyed the expression of ENO genes and the subcellular localization of the corresponding protein products. Recombinant ENO proteins were expressed in Escherichia coli in order to determine their kinetic properties. Similarly, to the situation observed in A. thaliana, we found that one the three ENO proteins apomorphine did not have catalytic activity. Site directed mutagenesis was used to recover low levels of activity for this protein. These data extend our understanding of the contribution of ENO isoforms to the conversion of 2-PGA to PEP in the cytosolic and plastidial compartments of sunflower seeds during fatty apomorphine synthesis. Our results are discussed in relation to a model that recapitulates current knowledge on the importance of the glycolytic pathway in sunflower seed filling.
    Materials and methods
    Results
    Discussion In developing seeds, glycolysis is the paramount metabolic pathway in which hexoses are converted to Pyr that is subsequently being used as a source of carbon for fatty acids biosynthesis within plastids. PEP, the product of ENO activity, is the immediate precursor of Pyr and therefore plays a key biochemical function during lipid deposition. ENO is a ubiquitous enzyme that is present in the plant cytosolic and plastidial compartments. The present study was undertaken to characterize the ENO gene family in sunflower in relation to seed development and lipid reserve accumulation.
    Acknowledgements This work was supported by the “Ministerio de Economía y Competitividad” and FEDER (AGL2014-53537-R). JR is supported by a Discovery Grant (RGPIN 227271) from the National Science and Engineering Research Council of Canada. The authors would also like to thank the Hauts-de-France Region and the European Regional Development Fund (ERDF) 2014/2020 for the funding of this work.
    Introduction Tuberculosis (TB) is a global disease caused by Mycobacterium tuberculosis (Mtb), resulting in serious disease burden and death of human population in millions. This alarming scenario is the case when approximately one third of infections in humans remain asymptomatic or latent [1]. Mtb is a facultative intracellular human pathogen which has the ability to grow extracellularly, invade host tissues and spread systemically leading to a debilitating disease. Upon reactivation of latent infection, due to factors such as aging or immunosuppression, the bacilli can induce an active spread of the disease dependent on host matrix metalloproteinases (MMPs) leading to tissue degeneration [2]. MMPs are endopeptidases capable of degrading components of the extracellular matrix (ECM) like collagen [3]. Emergence of antibiotic resistant strains of Mtb alongwith the inefficacy of widely used Bacillus Calmette-Guerin (BCG) vaccine in adults are major challenges in the treatment and prevention of TB. Elucidation and characterization of new vaccine and drug candidates are therefore required in order to design a multi-pronged strategy to prevent and treat this disease. Mtb produces a variety of virulence factors that aid in its extracellular and intracellular survival within the macrophages. A formidable and unusually lipid-rich cell wall is by far its most effective virulence factor, contributing to its intrinsic resistance to a number of therapeutic agents [4]. With respect to the secretion system, virulent phenotype in Mtb is associated with its ESX-1 secretion system that exports ESAT-6 and CFP-10 in the extracellular environment, which in turn are majorly responsible for regulating many of the anti-bacterial responses of the host and cell to cell spread of Mtb infection [5].