Occurrence of P503 in microorganisms

1973 ◽  
Vol 19 (10) ◽  
pp. 1235-1238
Author(s):  
Andrew M. B. Kropinski ◽  
Joyce Boon ◽  
Rozanne Poulson ◽  
W. James Polglase
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electron Transport ◽  
Functional Significance ◽  
Electron Transport Chain ◽  
Difference Spectra ◽  
Widespread Occurrence ◽  
Facultative Anaerobes ◽  
Transport Chain ◽  
Apparent Correlation ◽  
The Difference

A pigment absorbing at 503 nm (P503) was observed in the difference spectra of several strains of microorganisms. The pigment was present in most facultative anaerobes and absent from many but not all of the aerobes examined. P503 is probably not a component of the normal oxygen-linked electron transport chain since the pigment was present in both respiratory sufficient (ρ+) and deficient (ρ−) strains of Saccharomyces cerevisiae. There was no apparent correlation between P503 and either the cytochromes or any known metabolic cellular activities. However, the widespread occurrence of P503 in microorganisms suggests that it is of functional significance.

scholarly journals The oxidation of nicotinic acid by Pseudomonas ovalis Chester. The terminal oxidase

1972 ◽  
Vol 129 (3) ◽  
pp. 755-761 ◽  
Author(s):  
M. V. Jones ◽  
D. E. Hughes
Keyword(s):  
Electron Transport ◽  
Nicotinic Acid ◽  
Electron Transport Chain ◽  
Acid Oxidase ◽  
Terminal Oxidase ◽  
Difference Spectra ◽  
Terminal Oxidases ◽  
Cytochrome O ◽  
Transport Chain ◽  
Terminal Oxidation

In cell-free extracts of Pseudomonas ovalis nicotinic acid oxidase is confined to the wallmembrane fraction. It is associated with an electron-transport chain comprising b- and c-type cytochromes only, differing proportions of which are reduced by nicotinate and NADH. CO difference-spectra show two CO-binding pigments, cytochrome o (absorption maximum at 417nm) and another component absorbing maximally at 425nm. Cytochrome o is not reduced by NADH or by succinate but is by nicotinate, which can also reduce the ‘425’ CO-binding pigment. The effects of inhibitors of terminal oxidation support the idea of two terminal oxidases and a scheme involving the ‘425’ CO-binding pigment and the other components of the electron-transport chain is proposed.

scholarly journals A Chemogenomic Screen in Saccharomyces cerevisiae Uncovers a Primary Role for the Mitochondria in Farnesol Toxicity and Its Regulation by the Pkc1 Pathway

2006 ◽  
Vol 282 (7) ◽  
pp. 4868-4874 ◽  
Author(s):  
Gregory D. Fairn ◽  
Kendra MacDonald ◽  
Christopher R. McMaster
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reactive Oxygen Species ◽  
Cell Death ◽  
Electron Transport ◽  
Signaling Pathway ◽  
Electron Transport Chain ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Oxygen Species ◽  
Transport Chain

The isoprenoid farnesol has been shown to preferentially induce apoptosis in cancerous cells; however, the mode of action of farnesol-induced death is not established. We used chemogenomic profiling using Saccharomyces cerevisiae to probe the core cellular processes targeted by farnesol. This screen revealed 48 genes whose inactivation increased sensitivity to farnesol. The gene set indicated a role for the generation of oxygen radicals by the Rieske iron-sulfur component of complex III of the electron transport chain as a major mediator of farnesol-induced cell death. Consistent with this, loss of mitochondrial DNA, which abolishes electron transport, resulted in robust resistance to farnesol. A genomic interaction map predicted interconnectedness between the Pkc1 signaling pathway and farnesol sensitivity via regulation of the generation of reactive oxygen species. Consistent with this prediction (i) Pkc1, Bck1, and Mkk1 relocalized to the mitochondria upon farnesol addition, (ii) inactivation of the only non-essential and non-redundant member of the Pkc1 signaling pathway, BCK1, resulted in farnesol sensitivity, and (iii) expression of activated alleles of PKC1, BCK1, and MKK1 increased resistance to farnesol and hydrogen peroxide. Sensitivity to farnesol was not affected by the presence of the osmostabilizer sorbitol nor did farnesol affect phosphorylation of the ultimate Pkc1-responsive kinase responsible for controlling the cell wall integrity pathway, Slt2. The data indicate that the generation of reactive oxygen species by the electron transport chain is a primary mechanism by which farnesol kills cells. The Pkc1 signaling pathway regulates farnesol-mediated cell death through management of the generation of reactive oxygen species.

scholarly journals Farnesol-Induced Generation of Reactive Oxygen Species via Indirect Inhibition of the Mitochondrial Electron Transport Chain in the Yeast Saccharomyces cerevisiae

1998 ◽  
Vol 180 (17) ◽  
pp. 4460-4465 ◽  
Author(s):  
Kiyotaka Machida ◽  
Toshio Tanaka ◽  
Ken-ichi Fujita ◽  
Makoto Taniguchi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Growth Inhibition ◽  
Electron Transport Chain ◽  
Complex Iii ◽  
Ros Generation ◽  
Oxygen Species ◽  
Mitochondrial Electron Transport Chain ◽  
Transport Chain

ABSTRACT The mechanism of farnesol (FOH)-induced growth inhibition ofSaccharomyces cerevisiae was studied in terms of its promotive effect on generation of reactive oxygen species (ROS). The level of ROS generation in FOH-treated cells increased five- to eightfold upon the initial 30-min incubation, while cells treated with other isoprenoid compounds, like geraniol, geranylgeraniol, and squalene, showed no ROS-generating response. The dependence of FOH-induced growth inhibition on such an oxidative stress was confirmed by the protection against such growth inhibition in the presence of an antioxidant such as α-tocopherol, probucol, orN-acetylcysteine. FOH could accelerate ROS generation only in cells of the wild-type grande strain, not in those of the respiration-deficient petite mutant ([rho 0]), which illustrates the role of the mitochondrial electron transport chain as its origin. Among the respiratory chain inhibitors, ROS generation could be effectively eliminated with myxothiazol, which inhibits oxidation of ubiquinol to the ubisemiquinone radical by the Rieske iron-sulfur center of complex III, but not with antimycin A, an inhibitor of electron transport that is functional in further oxidation of the ubisemiquinone radical to ubiquinone in the Q cycle of complex III. Cellular oxygen consumption was inhibited immediately upon extracellular addition of FOH, whereas FOH and its possible metabolites failed to directly inhibit any oxidase activities detected with the isolated mitochondrial preparation. A protein kinase C (PKC)-dependent mechanism was suggested to exist in the inhibition of mitochondrial electron transport since FOH-induced ROS generation could be effectively eliminated with a membrane-permeable diacylglycerol analog which can activate PKC. The present study supports the idea that FOH inhibits the ability of the electron transport chain to accelerate ROS production via interference with a phosphatidylinositol type of signal.

Iba57p participates in maturation of a [2Fe–2S]-cluster Rieske protein and in formation of supercomplexes III/IV of Saccharomyces cerevisiae electron transport chain

Mitochondrion ◽  
2019 ◽  
Vol 44 ◽  
pp. 75-84 ◽  
Author(s):  
Luis A. Sánchez ◽  
Mauricio Gómez-Gallardo ◽  
Alma L. Díaz-Pérez ◽  
Christian Cortés-Rojo ◽  
Jesús Campos-García
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Rieske Protein ◽  
Transport Chain

Die kurzzeitigen ultravioletten Differenzspektren bei der Photosynthese

1968 ◽  
Vol 23 (2) ◽  
pp. 220-224 ◽  
Author(s):  
H. H. Stiehl ◽  
H. T. Witt
Keyword(s):  
Electron Transport Chain ◽  
Life Time ◽  
Difference Spectrum ◽  
Difference Spectra ◽  
Light Reaction ◽  
Background Light ◽  
Transport Chain ◽  
Light Excitation ◽  
The Difference

Plastoquinone PQ is engaged in photosynthesis 1. Difference spectra in the UV-region indicate that PQ is an intermediate in the electron transport chain 2. PQ is located as a pool between the two light reactions I and II 3. PQ is reduced by hνII and oxidized by hνI3. In this paper the difference spectra which occur during light excitation of spinach chloroplasts and chlorella vulgaris were measured in the UV-region with high resolution by the high sensitive method of periodical flash photometry 6.On excitation with long flashes (10—1 sec) the difference spectra are similar to those obtained when plastoquinone is reduced to hydroquinone in vitro (see figs. 1, 3 and 6). Deviations in the case of chlorella (fig. 4) are caused by additional NADP-reduction. After extraction of plastoquinone from chloroplasts the difference spectra do not occur during light excitation but they can be produced in full after reconstitution with synthetic plastoquinone A (see fig. 2).In the presents of far red background light (718 nm) which excites only light reaction I the magnitude of the spectrum is doubled (see fig. 3).By excitation with short flashes (10—5 sec), two different spectra were found. The difference spectrum with a life-time of 5 · 10—4 sec (fig. 7) is new and does not correspond to that of plastoquinone in vitro. The difference spectrum with a life-time of about 2·10—2 sec (fig. 5) corresponds to the plastoquinone reduction. The magnitude of this spectrum is ten times smaller than that obtained by excitation with long flashes (fig. 6).The 1:10 ratio of the magnitude of the spectra in short and long flashes can be interpreted by a pool of plastoquinone between the two light reactions with a dynamic capacity of ten electrons. The doubled magnitude of the spectra in far red background light can be interpreted by an electron acceptor pool for plastoquinone with a capacity of five electrons (see also the following papers).

scholarly journals RESPIRATION AND PROTEIN SYNTHESIS IN ESCHERICHIA COLI MEMBRANE-ENVELOPE FRAGMENTS

1970 ◽  
Vol 46 (1) ◽  
pp. 114-129 ◽  
Author(s):  
Richard W. Hendler ◽  
N. Nanninga
Keyword(s):  
Escherichia Coli ◽  
Carbon Monoxide ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Wave Length ◽  
Spectrophotometric Analysis ◽  
Difference Spectra ◽  
Absorption Bands ◽  
Optical Extinction ◽  
Transport Chain

The membranous nature of pellets obtained from broken Escherichia coli spheroplasts by successive centrifugation at 3500 g (P1), 20,000 g (P2), and 105,000 g (P3), has been established by electron microscopy. Spectrophotometric analysis has shown that about 90% of the cytochromes are concentrated in the particulate fractions. The crude ribosomal pellet (P3) contained as much of the total cytochromes as did the pellet obtained at 20,000 g (P2). The high cytochrome content of P3 is consistent with its high oxidative activity (1) and the presence of membrane vesicles in this fraction. Analysis at 77°K intensified the optical extinction of all the cytochrome absorption bands, but the degree of intensification was not uniform for each fraction nor for each band within a given fraction. Carbon monoxide had little or no inhibiting effect on NADH oxidation. Reduced plus carbon monoxide difference spectra yielded artifactual absorption bands in the wave length regions where reduced vs. oxidized absorption bands normally occur. Succinate and NADH, either together or separately, reduced nearly all of the cytochromes, indicating that the cytochrome portion of the electron-transport chain is shared by both substrates. A tentative formulation of the electron-transport chain is presented.

scholarly journals The Mechanisms of Thiosulfate Toxicity against Saccharomyces cerevisiae

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 646
Author(s):  
Zhigang Chen ◽  
Yongzhen Xia ◽  
Huaiwei Liu ◽  
Honglei Liu ◽  
Luying Xun
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Mitochondrial Membrane ◽  
Deletion Mutant ◽  
Elemental Sulfur ◽  
Yeast Mitochondria ◽  
Wild Type ◽  
Sulfurous Acid ◽  
Transport Chain

Elemental sulfur and sulfite have been used to inhibit the growth of yeasts, but thiosulfate has not been reported to be toxic to yeasts. We observed that thiosulfate was more inhibitory than sulfite to Saccharomyces cerevisiae growing in a common yeast medium. At pH < 4, thiosulfate was a source of elemental sulfur and sulfurous acid, and both were highly toxic to the yeast. At pH 6, thiosulfate directly inhibited the electron transport chain in yeast mitochondria, leading to reductions in oxygen consumption, mitochondrial membrane potential and cellular ATP. Although thiosulfate was converted to sulfite and H2S by the mitochondrial rhodanese Rdl1, its toxicity was not due to H2S as the rdl1-deletion mutant that produced significantly less H2S was more sensitive to thiosulfate than the wild type. Evidence suggests that thiosulfate inhibits cytochrome c oxidase of the electron transport chain in yeast mitochondria. Thus, thiosulfate is a potential agent against yeasts.

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