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Barichello T.,Laboratorio Of Microbiologia Experimental | Barichello T.,Instituto Nacional Of Ciencia E Tecnologia Translacional Em Medicina Inct Tm | Generoso J.S.,Laboratorio Of Microbiologia Experimental | Generoso J.S.,Instituto Nacional Of Ciencia E Tecnologia Translacional Em Medicina Inct Tm | And 5 more authors.
Oxidative Medicine and Cellular Longevity | Year: 2013

Pneumococcal meningitis is a life-threatening disease characterized by an acute purulent infection affecting the pia mater, the arachnoid, and the subarachnoid spaces. Streptococcus pneumoniae crosses the blood-brain barrier (BBB) by both transcellular traversal and disruption of the intraepithelial tight junctions to allow intercellular traversal. During multiplication, pneumococci release their bacterial products, which are highly immunogenic and may lead to an increased inflammatory response in the host. Thus, these compounds are recognized by antigen-presenting cells through the binding of toll-like receptors. These receptors induce the activation of myeloid differentiation factor 88 (MyD88), which interacts with various protein kinases, including IL-1 receptor-associated kinase-4 (IRAK4), which is phosphorylated and dissociated from MyD88. These products also interact with tumor necrosis factor receptor-associated factor 6 dependent signaling pathway (TRAF6). This cascade provides a link to NF-B-inducing kinase, resulting in the nuclear translocation of NF-B leading to the production of cytokines, chemokines, and other proinflammatory molecules in response to bacterial stimuli. Consequently, polymorphonuclear cells are attracted from the bloodstream and then activated, releasing large amounts of NO•, O 2 •, and H 2O2. This formation generates oxidative and nitrosative stress, subsequently, lipid peroxidation, mitochondrial damage, and BBB breakdown, which contributes to cell injury during pneumococcal meningitis. © 2013 Tatiana Barichello et al.

Esquivel-Cote R.,Laboratorio Of Microbiologia Experimental | Gavilanes-Ruiz M.,Conjunto E | Cruz-Ortega R.,Laboratorio Of Alelopatia | Pilar Huante Y.,National Autonomous University of Mexico
Revista Fitotecnia Mexicana | Year: 2013

The rhizosphere is a nutrient-rich soil region with important levels of microbial activity. In this zone, plants and some microorganisms such as plant growth-promoting rhizobacteria (PGPR) mutually interact for their benefit. These bacteria use one or several mechanisms to favor plants: either stimulating nutrients absorption or avoiding the action of pathogenic microorganisms. The activity of the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase is a strategy that some PGPR use to promote plant growth under specific environmental stress. This enzymatic activity provides two important advantages for plants: reducing ethylene concentration in the plant, and increasing ammonium availability at the rhizosphere. In this way, the activity of the ACC deaminase improves plant nutrition and resistance to stress factors. ACC deaminase-containing PGRP can be used to improve agricultural systems under arid and salt conditions, and at polluted environments with heavy metals. This review examined the basic aspects of the interaction between the PGPR and the plant and the ACC deaminase action mechanism. A compilation of the reported PGPR species and their application in agricultural and bioremediation is also presented.

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