Ponencias y Comunicaciones

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Browsing Ponencias y Comunicaciones by browse.metadata.contributordepartment "Bioquímica y Biología Molecular B e Inmunología"

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    Continuous intracellular pH measurement: Escherichia coli culture medium pH dependence
    (2021-05-04) Lozano Terol, Gema; Cánovas Díaz, Manuel; Diego Puente, Teresa de; Gallego Jara, Julia; Bioquímica y Biología Molecular B e Inmunología
    E. coli is the most used host microorganism to high-valuable compounds production in current industry. Cells pH homeostasis is a crucial factor to grow in different environment maintaining an intracellular pH control, however, to our knowledge, there is not a study about E. coli continuous intracellular pH growing in a culture. In this study the intracellular E. coli pH has been determined for cultures growing with glucose or glycerol as carbon sources. To determine intracellular E. coli pH, a novel, simple and accurate method based on pGFPR01 plasmid (kindly provided by Dr. Joan Slonczewski) was employed (1). This vector expressed ratiometric pHluorin. Thus, fluorescence ratio 410/470 showed a perfect lineal dependence with intracellular pH between 5.5 and 9. The results showed a surprising high intracellular pH for E. coli glucose cultures, which raised values of 8.5-9 at exponential growth phase. However, glycerol cultures showed a major regulation of intracellular pH, keeping the values at 6.5-7.5 in exponential and stationary stages. These differences show the dependence between the intracellular pH and the carbon source. In addition, the measurement method developed is a very useful tool for the control of bioprocesses.
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    The Mycobacterium marinum-zebrafish model to study host-pathogen interactions in tuberculosis
    (2018) Roca Soler, Francisco José; Bioquímica y Biología Molecular B e Inmunología
    While Tumor Necrosis Factor (TNF) is host protective in mycobacterial infections, its excess is pathogenic. TNF excess triggers production of mitochondrial reactive oxygen species (ROS) that cause programmed necrosis (necroptosis) of infected macrophages through the participation of the mitochondrial protein cyclophilin D, a regulator of mitochondrial permeability transition. Here we show that mitochondrial ROS mediate necrosis through a signaling pathway that traverses the lysosome, cytosol, and endoplasmic reticulum (ER) before returning to the mitochondrion to execute cell death. We have identified the specific proteins, including Ca2+ channels, which orchestrate this pathway, which we will present. In summary, we find that mitochondrial Ca2+ overload is the ultimate feature in the pathway responsible for TNF-mediated programmed necrosis in infected macrophages. We identify currently used calcium channel blockers as well as drugs that specifically inhibit ER calcium release as pharmacological interventions that prevent pathogenic necrosis in tuberculosis.