Effect of growth at low temperature on the alternative pathway respiration in Acanthamoeba castellanii mitochondria.

Jarmuszkiewicz, Wiesława; Fraczyk, O; Hryniewiecka, L.

doi:10.18388/abp.2001_3907

Cited by 21 publications

(14 citation statements)

References 39 publications

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“…This role could become especially important when the ROS level increases [14][15][16]. Therefore, the data presented in this work are consistent with our previous results showing that the activity and protein level of both, AcAOX and AcUCP, is enhanced by growth of amoeba cells in low temperature that is likely to be accompanied by a higher cellular ROS generation [11,12].…”

Section: Physiological Role Of Acucp and Acaox As Antioxidant Defensesupporting

confidence: 92%

“…In unicellular eukaryotes, because of their small size, which prevents any thermal gradient with their surroundings, thermogenesis has no place. Thus, the increase in activity and expression of AcAOX [11] and AcUCP [12] observed in A. castellanii mitochondria after the growth of amoeba cells at low temperature cannot be related to thermogenesis. Moreover, contrary to plant mitochondria [13], in mitochondria of A. castellanii, UCP and AOX can work together at their maximal capacities indicating a cumulative effect on oxidative Abbreviations: AA, antimycin A; AcAOX, alternative oxidase of Acanthamoeba castellanii; AcUCP, uncoupling protein of Acanthamoeba castellanii; AOX, alternative oxidase; BHAM, benzohydroxamate; BSA, bovine serum albumin; CAT, carboxyatractyloside; FFA, free fatty acids; H 2 O 2 , hydrogen peroxide; LA, linoleic acid; ROS, reactive oxygen species; UCP, uncoupling protein; DlH + , proton electrochemical gradient phosphorylation [5].…”

Section: Introductionmentioning

confidence: 93%

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Activation of alternative oxidase and uncoupling protein lowers hydrogen peroxide formation in amoeba Acanthamoeba castellanii mitochondria

Czarna

Jarmuszkiewicz

2005

FEBS Letters

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Mitochondria of amoeba Acanthamoeba castellanii were used to determine the role of two energy-dissipating systems, i.e., a free fatty acid (FFA)-activated, purine nucleotideinhibited uncoupling protein (AcUCP) and a FFA-insensitive, purine nucleotide-activated ubiquinol alternative oxidase (AcAOX), in decreasing reactive oxygen species production in unicellular organisms. It is shown that the activation of AcUCP by externally added FFA resulted in a strong decrease in H 2 O 2 production, whilst the inhibition of the FFA acid-induced AcUCP activity by GDP or addition of bovine serum albumin (BSA) enhanced production of H 2 O 2 . Similarly, the activation of antimycin-resistant AcAOX-mediated respiration by GMP significantly lowered H 2 O 2 production, while inhibition of the oxidase by benzohydroxamate cancelled the GMP-induced effect on H 2 O 2 production. When active together, both energy-dissipating systems revealed a cumulative effect on decreasing H 2 O 2 formation. The results suggest that protection against mitochondrial oxidative stress may be a physiological role of AOX and UCP in unicellulars, such as A. castellanii.

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Section: Physiological Role Of Acucp and Acaox As Antioxidant Defensesupporting

confidence: 92%

Section: Introductionmentioning

confidence: 93%

Activation of alternative oxidase and uncoupling protein lowers hydrogen peroxide formation in amoeba Acanthamoeba castellanii mitochondria

Czarna

Jarmuszkiewicz

2005

FEBS Letters

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“…The amoeboid protozoan A. castellanii and higher plants share several common features at the level of the respiratory chain of the inner mitochondrial membrane such as the presence of an alternative ubiquinol cyanide-resistant oxidase and non-phosphorylating rotenone-insensitive internal (matricial face) and external (cytosolic face) NADH dehydrogenases [14,15]. Our previous results have shown that the activity and protein content of A. castellanii alternative oxidase is clearly increased by a growth of amoeba cells at low temperature [16]. Both, alternative oxidase and UCP, are free energy-dissipating systems which lead to the same final effect, i.e., a decrease in ATP synthesis.…”

Section: Introductionmentioning

confidence: 98%

The effect of growth at low temperature on the activity and expression of the uncoupling protein in Acanthamoeba castellanii mitochondria

et al. 2004

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Mitochondria of amoeba Acanthamoeba castellanii, a non-photosynthetic soil amoeboid protozoon, possess an uncoupling protein (AcUCP) that mediates free fatty acid-activated proton re-uptake dissipating the proton electrochemical gradient built up by respiration. The present study provides the first evidence that UCP could be a cold response protein in unicellulars. In mitochondria isolated from an amoeba batch culture grown temporarily at low temperature (6°C), the content of AcUCP was increased and correlated with an increase in the linoleic acid (LA)-stimulated UCP-mediated carboxyatractyloside-resistant state 4 respiration, as compared to a control culture (routinely grown at 28°C). Moreover, the cytochrome pathway activity was found to be insensitive to the cold exposure of amoeba cells, as indicated by respiration and membrane potential measurements as well as by an absence of change in the adenine nucleotide translocator and cytochrome oxidase expression levels. Furthermore, in mitochondria from the low-temperature-grown cells, at fixed LA concentration, the increased contribution of AcUCP activity to total mitochondrial phosphorylating respiration accompanied by lower coupling parameters was found, as was confirmed by calculation of this contribution using ADP/O measurements.

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“…Angert et al (2003) also reported low α k values (mean of 0.977, SD of 0.004) for O 2 consumption in a vadose zone in the interior of Alaska (63°49′N, 144°59′W). They attributed the low α k values to O 2 consumption by the alternative cyanide‐resistant oxidase pathway, which is more active in respiration at lower temperatures (Reyes and Jennings, 1997; Jarmuszkiewcz et al, 2001; Angert et al, 2003).…”

Section: Resultsmentioning

confidence: 99%

A Transient Model of Vadose Zone Reaction Rates Using Oxygen Isotopes and Carbon Dioxide

Birkham

Hendry

Wassenaar

et al. 2007

Vadose Zone Journal

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The importance of identifying and quantifying subsurface geochemical reaction rates and processes by monitoring and modeling CO 2 and O 2 concentrations is well established. These parameters, however, are typically studied independently under presumed steadystate conditions. Here we present models of seasonally variable vadose zone CO 2 and O 2 concentrations that use d 18 O of O 2 as a constraint to create a dynamic link between these three parameters under transient conditions. The gas transport modeling was used to quantify the controls of biogeochemical processes and parameters (i.e., temperature and moisture content) on vadose zone distributions of CO 2 and O 2 gas concentrations. The investigation was conducted on a 3-m-thick, unvegetated, fine-sand vadose zone located in northern Alberta, Canada (56°40 ¶N, 111°07 ¶W). Using the modeled molar ratio of surface fluxes for O 2 and CO 2 , the change in reaction rate for a temperature change of 10°C (Q 10 ), moisture content at maximum reaction rates, and biogeochemical discrimination against consumption of 18 O 16 O (a k ), we determined that organic C oxidation by microbial respiration was the predominant mechanism consuming O 2 and producing CO 2 . The mean a k was determined to be 0.973, suggesting that subsurface respiration was via the alternative oxidase pathway, which may be common in cold climates. Modeling revealed that the moisture content of a moist, surficial clayey sand layer (0.1-0.3 m thick) had a dramatic effect on pore-gas CO 2 and O 2 concentrations and on d 18 O O2 . The vadose zone in this study was at an unvegetated site to simplify the model application; however, it can be modified to include root respiration and applied to natural vadose zones to help quantify the role of subsurface respiration in global O 2 and C budgets.

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Effect of growth at low temperature on the alternative pathway respiration in Acanthamoeba castellanii mitochondria.

Cited by 21 publications

References 39 publications

Activation of alternative oxidase and uncoupling protein lowers hydrogen peroxide formation in amoeba Acanthamoeba castellanii mitochondria

Activation of alternative oxidase and uncoupling protein lowers hydrogen peroxide formation in amoeba Acanthamoeba castellanii mitochondria

The effect of growth at low temperature on the activity and expression of the uncoupling protein in Acanthamoeba castellanii mitochondria

A Transient Model of Vadose Zone Reaction Rates Using Oxygen Isotopes and Carbon Dioxide

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