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Stanić M, Križak S, Jovanović M, Pajić T, Ćirić A, Žižić M, Zakrzewska J, Antić TC, Todorović N, Živić M. Growth inhibition of fungus Phycomyces blakesleeanus by anion channel inhibitors anthracene-9-carboxylic and niflumic acid attained through decrease in cellular respiration and energy metabolites. MICROBIOLOGY-SGM 2017; 163:364-372. [PMID: 28100310 DOI: 10.1099/mic.0.000429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Increasing resistance of fungal strains to known fungicides has prompted identification of new candidates for fungicides among substances previously used for other purposes. We have tested the effects of known anion channel inhibitors anthracene-9-carboxylic acid (A9C) and niflumic acid (NFA) on growth, energy metabolism and anionic current of mycelium of fungus Phycomyces blakesleeanus. Both inhibitors significantly decreased growth and respiration of mycelium, but complete inhibition was only achieved by 100 and 500 µM NFA for growth and respiration, respectively. A9C had no effect on respiration of human NCI-H460 cell line and very little effect on cucumber root sprout clippings, which nominates this inhibitor for further investigation as a potential new fungicide. Effects of A9C and NFA on respiration of isolated mitochondria of P. blakesleeanus were significantly smaller, which indicates that their inhibitory effect on respiration of mycelium is indirect. NMR spectroscopy showed that both A9C and NFA decrease the levels of ATP and polyphosphates in the mycelium of P. blakesleeanus, but only A9C caused intracellular acidification. Outwardly rectifying, fast inactivating instantaneous anionic current (ORIC) was also reduced to 33±5 and 21±3 % of its pre-treatment size by A9C and NFA, respectively, but only in the absence of ATP. It can be assumed from our results that the regulation of ORIC is tightly linked to cellular energy metabolism in P. blakesleeanus, and the decrease in ATP and polyphosphate levels could be a direct cause of growth inhibition.
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Affiliation(s)
- Marina Stanić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - Strahinja Križak
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - Mirna Jovanović
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Tanja Pajić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - Ana Ćirić
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Milan Žižić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - Joanna Zakrzewska
- Institute of General and Physical Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia
| | - Tijana Cvetić Antić
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
| | - Nataša Todorović
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Miroslav Živić
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
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Schinagl CW, Vrabl P, Burgstaller W. Adapting High-Resolution Respirometry to Glucose-Limited Steady State Mycelium of the Filamentous Fungus Penicillium ochrochloron: Method Development and Standardisation. PLoS One 2016; 11:e0146878. [PMID: 26771937 PMCID: PMC4714917 DOI: 10.1371/journal.pone.0146878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 12/24/2015] [Indexed: 11/29/2022] Open
Abstract
Fungal electron transport systems (ETS) are branched, involving alternative NADH dehydrogenases and an alternative terminal oxidase. These alternative respiratory enzymes were reported to play a role in pathogenesis, production of antibiotics and excretion of organic acids. The activity of these alternative respiratory enzymes strongly depends on environmental conditions. Functional analysis of fungal ETS under highly standardised conditions for cultivation, sample processing and respirometric assay are still lacking. We developed a highly standardised protocol to explore in vivo the ETS—and in particular the alternative oxidase—in Penicillium ochrochloron. This included cultivation in glucose-limited chemostat (to achieve a defined and reproducible physiological state), direct transfer without any manipulation of a broth sample to the respirometer (to maintain the physiological state in the respirometer as close as possible to that in the chemostat), and high-resolution respirometry (small sample volume and high measuring accuracy). This protocol was aimed at avoiding any changes in the physiological phenotype due to the high phenotypic plasticity of filamentous fungi. A stable oxygen consumption (< 5% change in 20 minutes) was only possible with glucose limited chemostat mycelium and a direct transfer of a broth sample into the respirometer. Steady state respiration was 29% below its maximum respiratory capacity. Additionally to a rotenone-sensitive complex I and most probably a functioning complex III, the ETS of P. ochrochloron also contained a cyanide-sensitive terminal oxidase (complex IV). Activity of alternative oxidase was present constitutively. The degree of inhibition strongly depended on the sequence of inhibitor addition. This suggested, as postulated for plants, that the alternative terminal oxidase was in dynamic equilibrium with complex IV—independent of the rate of electron flux. This means that the onset of activity does not depend on a complete saturation or inhibition of the cytochrome pathway.
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Affiliation(s)
| | - Pamela Vrabl
- University of Innsbruck, Institute of Microbiology, Innsbruck, Austria
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Rúa J, de Castro C, de Arriaga D, García-Armesto MR, Busto F, del Valle P. Stress in Phycomyces blakesleeanus by glucose starvation and acetate growth: Response of the antioxidant system and reserve carbohydrates. Microbiol Res 2014; 169:788-93. [DOI: 10.1016/j.micres.2013.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/05/2013] [Accepted: 12/20/2013] [Indexed: 01/01/2023]
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Stanić M, Zakrzewska J, Hadžibrahimović M, Zižić M, Marković Z, Vučinić Z, Zivić M. Oxygen regulation of alternative respiration in fungus Phycomyces blakesleeanus: connection with phosphate metabolism. Res Microbiol 2013; 164:770-8. [PMID: 23542427 DOI: 10.1016/j.resmic.2013.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 03/11/2013] [Indexed: 11/27/2022]
Abstract
Environmental changes can often result in oxygen deficiency which influences cellular energy metabolism, but such effects have been insufficiently studied in fungi. The effects of oxygen deprivation on respiration and phosphate metabolites in Phycomyces blakesleeanus were investigated by oxygen electrode and (31)P NMR spectroscopy. Mycelium was incubated in hypoxic and anoxic conditions for 1.5, 3 and 5 h and then reoxygenated. Participation of alternative oxidase (AOX) in total respiration increased gradually in both treatments and after 5 h of anoxia exceeded a value 50% higher than in control. Shortly after reintroduction of oxygen into the system AOX level decreased close to the control level. Oxygen deprivation also caused a reversible decrease of polyphosphate/inorganic phosphate ratio (PPc/Pi), which was strongly correlated with the increase of AOX participation in total respiration. Unexpectedly, ATP content remained almost constant, probably due to the ability of PolyP to sustain energy and phosphate homeostasis of the cell under stress conditions. This was further substantiated by the effects of azide, a cytochrome c oxidase inhibitor, which also decreased PPc/Pi ratio, but to a smaller extent in oxygen deprived than control and reoxygenated specimens.
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Affiliation(s)
- Marina Stanić
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
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Antifungal activity and action mode of pinocembrin from propolis against Penicillium italicum. Food Sci Biotechnol 2012. [DOI: 10.1007/s10068-012-0204-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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