Browsing by Subject "NADPH OXIDASE"

Sort by: Order: Results:

Now showing items 1-2 of 2
  • Amini, Poorya; Stojkov, Darko; Felser, Andrea; Jackson, Christopher B.; Courage, Carolina; Schaller, Andre; Gelman, Laurent; Soriano, Maria Eugenia; Nuoffer, Jean-Marc; Scorrano, Luca; Benarafa, Charaf; Yousefi, Shida; Simon, Hans-Uwe (2018)
    Optic atrophy 1 (OPA1) is a mitochondrial inner membrane protein that has an important role in mitochondrial fusion and structural integrity. Dysfunctional OPA1 mutations cause atrophy of the optic nerve leading to blindness. Here, we show that OPA1 has an important role in the innate immune system. Using conditional knockout mice lacking Opa1 in neutrophils (Opa1(N Delta)), we report that lack of OPA1 reduces the activity of mitochondrial electron transport complex I in neutrophils. This then causes a decline in adenosine-triphosphate (ATP) production through glycolysis due to lowered NAD(+) availability. Additionally, we show that OPA1-dependent ATP production in these cells is required for microtubule network assembly and for the formation of neutrophil extracellular traps. Finally, we show that Opa1(N Delta) mice exhibit a reduced antibacterial defense capability against Pseudomonas aeruginosa.
  • Nuhkat, Maris; Brosché, Mikael; Stoelzle-Feix, Sonja; Dietrich, Petra; Hedrich, Rainer; Roelfsema, M.Rob G.; Kollist, Hannes (2021)
    Plant stress signalling involves bursts of reactive oxygen species (ROS), which can be mimicked by the application of acute pulses of ozone. Such ozone-pulses inhibit photosynthesis and trigger stomatal closure in a few minutes, but the signalling that underlies these responses remains largely unknown. We measured changes in Arabidopsis thaliana gas exchange after treatment with acute pulses of ozone and set up a system for simultaneous measurement of membrane potential and cytosolic calcium with the fluorescent reporter R-GECO1. We show that within 1 min, prior to stomatal closure, O3 triggered a drop in whole-plant CO2 uptake. Within this early phase, O3 pulses (200–1000 ppb) elicited simultaneous membrane depolarization and cytosolic calcium increase, whereas these pulses had no long-term effect on either stomatal conductance or photosynthesis. In contrast, pulses of 5000 ppb O3 induced cell death, systemic Ca2+ signals and an irreversible drop in stomatal conductance and photosynthetic capacity. We conclude that mesophyll cells respond to ozone in a few seconds by distinct pattern of plasma membrane depolarizations accompanied by an increase in the cytosolic calcium ion (Ca2+) level. These responses became systemic only at very high ozone concentrations. Thus, plants have rapid mechanism to sense and discriminate the strength of ozone signals. © 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation