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1.
Aspergillus fumigatus protein phosphatase PpzA is involved in iron assimilation,secondary metabolite production,and virulence
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Adriana Oliveira Manfiolli Patrícia Alves de Castro Thaila Fernanda dos Reis Stephen Dolan Sean Doyle Gary Jones Diego M. Riaño Pachón Mevlüt Ulaş Luke M. Noble Derek J. Mattern Axel A. Brakhage Vito Valiante Rafael Silva‐Rocha Ozgur Bayram Gustavo H. Goldman 《Cellular microbiology》2017,19(12)
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Multiple modes of iron uptake by the filamentous,siderophore‐producing cyanobacterium,Anabaena sp. PCC 7120
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Mareike Rudolf Chana Kranzler Hagar Lis Ketty Margulis Mara Stevanovic Nir Keren Enrico Schleiff 《Molecular microbiology》2015,97(3):577-588
Iron is a member of a small group of nutrients that limits aquatic primary production. Mechanisms for utilizing iron have to be efficient and adapted according to the ecological niche. In respect to iron acquisition cyanobacteria, prokaryotic oxygen evolving photosynthetic organisms can be divided into siderophore‐ and non‐siderophore‐producing strains. The results presented in this paper suggest that the situation is far more complex. To understand the bioavailability of different iron substrates and the advantages of various uptake strategies, we examined iron uptake mechanisms in the siderophore‐producing cyanobacterium Anabaena sp. PCC 7120. Comparison of the uptake of iron complexed with exogenous (desferrioxamine B, DFB) or to self‐secreted (schizokinen) siderophores by Anabaena sp. revealed that uptake of the endogenous produced siderophore complexed to iron is more efficient. In addition, Anabaena sp. is able to take up dissolved, ferric iron hydroxide species (Fe′) via a reductive mechanism. Thus, Anabaena sp. exhibits both, siderophore‐ and non‐siderophore‐mediated iron uptake. While assimilation of Fe′ and FeDFB are not induced by iron starvation, FeSchizokinen uptake rates increase with increasing iron starvation. Consequently, we suggest that Fe′ reduction and uptake is advantageous for low‐density cultures, while at higher densities siderophore uptake is preferred. 相似文献
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Christian Cortés-Rojo Elizabeth Calderón-Cortés Mónica Clemente-Guerrero Mirella Estrada-Villagómez Salvador Manzo-Avalos Ricardo Mejía-Zepeda Istvan Boldogh Alfredo Saavedra-Molina 《Journal of bioenergetics and biomembranes》2009,41(1):15-28
Lipoperoxidative damage to the respiratory chain proteins may account for disruption in mitochondrial electron transport chain
(ETC) function and could lead to an augment in the production of reactive oxygen species (ROS). To test this hypothesis, we
investigated the effects of lipoperoxidation on ETC function and cytochromes spectra of Saccharomyces cerevisiae mitochondria. We compared the effects of Fe2+ treatment on mitochondria isolated from yeast with native (lipoperoxidation-resistant) and modified (lipoperoxidation-sensitive)
fatty acid composition. Augmented sensitivity to oxidative stress was observed in the complex III-complex IV segment of the
ETC. Lipoperoxidation did not alter the cytochromes content. Under lipoperoxidative conditions, cytochrome c reduction by succinate was almost totally eliminated by superoxide dismutase and stigmatellin. Our results suggest that lipoperoxidation
impairs electron transfer mainly at cytochrome b in complex III, which leads to increased resistance to antimycin A and ROS generation due to an electron leak at the level
of the QO site of complex III. 相似文献
5.
Xanthoferrin,the α‐hydroxycarboxylate‐type siderophore of Xanthomonas campestris pv. campestris,is required for optimum virulence and growth inside cabbage
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Sheo Shankar Pandey Pradeep Kumar Patnana Rikky Rai Subhadeep Chatterjee 《Molecular Plant Pathology》2017,18(7):949-962
Xanthomonas campestris pv. campestris causes black rot, a serious disease of crucifers. Xanthomonads encode a siderophore biosynthesis and uptake gene cluster xss (Xanthomonas siderophore synthesis) involved in the production of a vibrioferrin‐type siderophore. However, little is known about the role of the siderophore in the iron uptake and virulence of X. campestris pv. campestris. In this study, we show that X. campestris pv. campestris produces an α‐hydroxycarboxylate‐type siderophore (named xanthoferrin), which is required for growth under low‐iron conditions and for optimum virulence. A mutation in the siderophore synthesis xssA gene causes deficiency in siderophore production and growth under low‐iron conditions. In contrast, the siderophore utilization ΔxsuA mutant is able to produce siderophore, but exhibits a defect in the utilization of the siderophore–iron complex. Our radiolabelled iron uptake studies confirm that the ΔxssA and ΔxsuA mutants exhibit defects in ferric iron (Fe3+) uptake. The ΔxssA mutant is able to utilize and transport the exogenous xanthoferrin–Fe3+ complex; in contrast, the siderophore utilization or uptake mutant ΔxsuA exhibits defects in siderophore uptake. Expression analysis of the xss operon using a chromosomal gusA fusion indicates that the xss operon is expressed during in planta growth and under low‐iron conditions. Furthermore, exogenous iron supplementation in cabbage leaves rescues the in planta growth deficiency of ΔxssA and ΔxsuA mutants. Our study reveals that the siderophore xanthoferrin is an important virulence factor of X. campestris pv. campestris which promotes in planta growth by the sequestration of Fe3+. 相似文献
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The influence of iron, aluminium and of the combined application of both metals on microbial biomass and production of siderophores
by three fungi (Aspergillus nidulans, Neurospora crassa and Hymenoscyphus ericae) were investigated. All three species showed a strong iron regulation and Al-sensitivity of siderophore biosynthesis although
several differences remained species dependent. Inhibitory effects of Fe and Al on siderophore-production were additive and
the higher binding capacity of siderophores towards iron could be compensated by a higher Al-availability. Although pH itself
is also important for regulation of siderophore biosynthesis, an indirect effect of Al on siderophore production via an Al-induced
pH decrease could be outlined. The toxic effects of Al resulting in a reduced biomass production were compensated by high
Fe-availability, whereas the addition of DFAM, a bacterial siderophore, enhanced Al-toxicity. 相似文献
7.
Hema S. Aluri David C. Simpson Jeremy C. Allegood Ying Hu Karol Szczepanek Scott Gronert Qun Chen Edward J. Lesnefsky 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Cytochrome c (Cyt c) is a mobile component of the electron transport chain (ETC.) which contains a tightly coordinated heme iron. In pathologic settings, a key ligand of the cyt c's heme iron, methionine (Met80), is oxidized allowing cyt c to participate in reactions as a peroxidase with cardiolipin as a target. Myocardial ischemia (ISC) results in ETC. blockade and increased production of reactive oxygen species (ROS). We hypothesized that during ischemia–reperfusion (ISC-REP); ROS generation coupled with electron flow into cyt c would oxidize Met80 and contribute to mitochondrial-mediated ETC. damage.Methods
Mitochondria were incubated with specific substrates and inhibitors to test the contributions of ROS and electron flow into cyt c. Subsequently, cyt c and cardiolipin were analyzed. To test the pathophysiologic relevance, mouse hearts that underwent ISC-REP were tested for methionine oxidation in cyt c.Results
The combination of substrate/inhibitor showed that ROS production and electron flux through cyt c are essential for the oxidation of methionine residues that lead to cardiolipin depletion. The content of cyt c methionine oxidation increases following ISC-REP in the intact heart.Conclusions
Increase in intra-mitochondrial ROS coupled with electron flow into cyt c, oxidizes cyt c followed by depletion of cardiolipin. ISC-REP increases methionine oxidation, supporting that cyt c peroxidase activity can form in the intact heart.General significance
This study identifies a new site in the ETC. that is damaged during cardiac ISC-REP. Generation of a neoperoxidase activity of cyt c favors the formation of a defective ETC. that activates signaling for cell death. 相似文献8.
Cortés-Rojo C Estrada-Villagómez M Calderón-Cortés E Clemente-Guerrero M Mejía-Zepeda R Boldogh I Saavedra-Molina A 《Journal of bioenergetics and biomembranes》2011,43(2):135-147
The mitochondrial electron transport chain (ETC) contains thiol groups (−SH) which are reversibly oxidized to modulate ETC
function during H2O2 overproduction. Since deleterious effects of H2O2 are not limited to –SH oxidation, due to the formation of other H2O2-derived species, some processes like lipoperoxidation could enhance the effects of H2O2 over ETC enzymes, disrupt their modulation by –SH oxidation and increase superoxide production. To verify this hypothesis,
we tested the effects of H2O2 on ETC activities, superoxide production and iron mobilization in mitochondria from lipoperoxidation-resistant native yeast
and lipoperoxidation-sensitized yeast. Only complex III activity from lipoperoxidation-sensitive mitochondria exhibited a
higher susceptibility to H2O2 and increased superoxide production. The recovery of ETC activity by the thiol reductanct β-mercaptoethanol (BME) was also
altered at complex III, and a role was attributed to lipoperoxidation, the latter being also responsible for iron release.
A hypothetical model linking lipoperoxidation, increased complex III damage, superoxide production and iron release is given. 相似文献
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Sergey N. Gavrilov Jonathan R. Lloyd Nadezhda A. Kostrikina Alexander I. Slobodkin 《Geomicrobiology journal》2013,30(9):804-819
Physiological strategies driving the reduction of poorly crystalline Fe(III) oxide by the thermophilic Gram-positive dissimilatory Fe(III)-reducing bacterium C. ferrireducens were evaluated. Direct cell-to-mineral contact appears to be the major physiological strategy for ferrihydrite reduction. This strategy is promoted by cell surface-associated c-type cytochromes, and the extracellular electron transfer to ferrihydrite is linked to energy generation via a membrane-bound electron transport chain. The involvement of pili-like appendages in ferrihydrite reduction has been detected for the first time in a thermophilic microorganism. A supplementary strategy for the utilization of a siderophore (DFO) in dissimilatory ferrihydrite reduction has also been characterized. 相似文献
12.
《Translational oncology》2020,13(11):100843
Ferroptosis is a novel form of programmed cell death characterized by an iron-dependent increase in reactive oxygen species (ROS). However, the role of ROS in the regulation of ferroptosis remains elusive. In this study, for the first time, we demonstrate that sodium selenite (SS), a well-established redox-active selenium compound, is a novel inducer of ferroptosis in a variety of human cancer cells. Potent ferroptosis inhibitors, such as ferrostatin-1 (Fer-1) and deferoxamine (DFO), rescue cells from SS-induced ferroptosis. Furthermore, SS down-regulates ferroptosis regulators; solute carrier family 7 member 11 (SLC7A11), glutathione (GSH), and glutathione peroxidase 4 (GPx4), while it up-regulates iron accumulation and lipid peroxidation (LPO). These SS-induced ferroptotic responses are achieved via ROS, in particular superoxide (O2−) generation. Antioxidants such as superoxide dismutase (SOD) and Tiron not only scavenged O2− production, but also markedly rescued SLC7A11 down-regulation, GSH depletion, GPx4 inactivation, iron accumulation, LPO, and ferroptosis. Moreover, iron chelator DFO significantly reduces the O2− production, indicating a positive feedback regulation between O2− production and iron accumulation. Taken together, we have identified SS as a novel ferroptosis inducing agent in various human cancer models. 相似文献
13.
Aims: To characterize the luxO gene in fish pathogen Vibrio alginolyticus MVP01 and investigate its roles in regulation of extracellular products (ECP) and siderophore production. Methods and Results: The luxO gene was cloned from V. alginolyticus MVP01. Genetic analysis revealed that it encoded a protein with high similarity to other LuxO homologues. The luxO in-frame deletion mutant and rpoN null mutant were constructed with suicide plasmids. We demonstrated that sole deletion in LuxO increased the secretion of extracellular protease and haemolytic products, but decreased siderophore production for V. alginolyticus MVP01. Mutants with null rpoN displayed significantly enhanced protease level and siderophore production while notable reduction in haemolytic activities of ECP. Conclusions: Vibrio alginolyticus harbours functional luxO gene that regulates the secretion of extracellular protease and haemolytic materials as well as siderophore production in either σ54 dependent or independent manners. Significance and Impact of the Study: The current study demonstrated that V. alginolyticus MVP01 produces extracellular protease and haemolytic activity material as well as siderophore, which may be characteristics of the virulence of the strain. Revelations that secretion of these products is under the regulation of LuxO and σ54 as well as the potential quorum sensing systems in V. alginolyticus MVP01 will expedite the understanding of vibriosis pathogenesis. 相似文献
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Iron is an essential component of many proteins, and has crucial roles in the proper functioning of proteins involved in cellular respiration, proliferation, and differentiation. It has been recently reported that the deferoxamine (DFO), an iron chelator, induces mitochondrial dysfunction, characterized by an attenuation of oxidative phosphorylation, as well as senescence-like cellular morphology. However, the effects of DFO on mitochondrial heat shock proteins (HSPs) remain poorly understood. In this study, we examined the effect of DFO on tumor necrosis factor receptor-associated protein 1 (TRAP1), a representative mitochondrial HSP, in a normal human hepatocyte cell line, Chang cells. DFO specifically decreased TRAP1 levels, increasing reactive oxygen species (ROS) and caveolin-1 (Cav-1), a marker protein of senescence. To examine whether these effects of DFO are reversed, we established TRAP1-overexpressing Chang cells. DFO treatment to TRAP1-overexpressing cells resulted in decreases in levels of ROS, Cav-1, glutathione peroxidase (GPX), and manganese superoxide dismutase (MnSOD) levels as well as senescence-associated beta-galactosidase (SA beta-gal) activity. These results suggest that TRAP1 might play a role in protecting mitochondria against damaging stimuli via decrease of ROS generation. 相似文献
16.
Reactive oxygen species (ROS) comprise a range of reactive and short-lived, oxygen-containing molecules, which are dynamically interconverted or eliminated either catalytically or spontaneously. Due to the short life spans of most ROS and the diversity of their sources and subcellular localizations, a complete picture can be obtained only by careful measurements using a combination of protocols. Here, we present a set of three different protocols using OxyBurst Green (OBG)-coated beads, or dihydroethidium (DHE) and Amplex UltraRed (AUR), to monitor qualitatively and quantitatively various ROS in professional phagocytes such as Dictyostelium. We optimised the beads coating procedures and used OBG-coated beads and live microscopy to dynamically visualize intraphagosomal ROS generation at the single cell level. We identified lipopolysaccharide (LPS) from E. coli as a potent stimulator for ROS generation in Dictyostelium. In addition, we developed real time, medium-throughput assays using DHE and AUR to quantitatively measure intracellular superoxide and extracellular H2O2 production, respectively. 相似文献
17.
P. G. Gunasekar A. G. Kanthasamy J. L. Borowitz G. E. Isom 《Journal of neurochemistry》1995,65(5):2016-2021
Abstract: The ability of glutamate to stimulate generation of intracellular oxidant species was determined by microfluorescence in cerebellar granule cells loaded with the oxidant-sensitive fluorescent dye 2,7-dichlorofluorescin (DCF). Exposure of cells to glutamate (10 µM) produced a rapid generation of oxidants that was blocked ~70% by MK-801 (a noncompetitive NMDA-receptor antagonist). To determine if nitric oxide (NO) or reactive oxygen species (ROS) contributed to the oxidation of DCF, cells were treated with compounds that altered their generation. NO production was inhibited with NG-nitro-l -arginine methyl ester (l -NAME) (nitric oxide synthase inhibitor) and reduced hemoglobin (NO scavenger). Alternatively, cells were incubated with superoxide dismutase (SOD) and catalase, which selectively metabolize O2?· andH2O2. Concurrent inhibition of O2?· and NO production nearly abolished intracellular oxidant generation. Pretreatment of cells with either chelerythrine (1 µM, protein kinase C inhibitor) or quinacrine (5 µM, phospholipase A2 inhibitor) before addition of glutamate also blocked oxidation of DCF. Generation of oxidants by glutamate was significantly reduced by incubating the cells in Ca2+-free buffer. In cytotoxicity studies, a positive correlation was observed between glutamate-induced death and oxidant generation. Glutamate-induced cytotoxicity was blocked by MK-801 and attenuated by treatment with l -NAME, chelerythrine, SOD, or quinacrine. It is concluded that glutamate induces concurrent generation of NO and ROS by activation of both NMDA receptors and non-NMDA receptors through a Ca2+-mediated process. Activation of NO synthase and phospholipaseA2 contribute significantly to this response. It is proposed that simultaneous generation of NO and ROS results in formation of peroxynitrite, which initiates the cellular damage. 相似文献
18.
Elena L
PEZ-ERRASQUÍN M. Teresa GONZLEZ-JAN Carmen CALLEJAS Covadonga VZQUEZ 《Mycological Research》2006,110(9):1102-1110
The major facilitator superfamily (MFS) is a ubiquitous group of proteins involved in the transport of a wide range of compounds, including toxins produced by fungal species. In this paper, a novel MFS encoding gene (Fusarium iron related gene or FIR1), which had shown an up-regulation in fumonisin-inducing conditions, has been identified and characterized. The deduced protein sequence, which predicted 14 transmembrane domains typical of MFS transporters and its phylogenetic relationships with representative members of MFS transporters suggested a possible function of FIR1 as a siderophore transporter. A real-time RT-PCR protocol has been developed to analyse the expression pattern of the FIR1 gene in relation to siderophore production. The results indicated that the synthesis of extracellular siderophores by F. verticillioides observed in absence of extracellular iron was repressed in iron-supplemented cultures and showed a good correspondence with FIR1 gene expression. However, the pattern of FIR1 gene expression observed suggested that this gene did not seem to be functionally related to fumonisin production. 相似文献
19.
The production, detection and the effects of iron concentration on the siderophore production ofStaphylococcus strains used as meat starter cultures were studied. Non-pathogenicStaphylococcus strains produce extracellular low molecular weight compounds which exhibited positive reactivity when measured by a universal detection method for siderophores. The production of siderophores was very closely associated with the iron concentration in the medium, and very low additions considerably reduced siderophore production. Although the production of siderophores was highly iron-dependent, the antimicrobial activity of spent medium fromStaphylococcus cultures against selected yeasts and moulds remained considerable under high iron concentrations. 相似文献
20.
Alexander Anderson Anuphon Laohavisit Ian K. Blaby Paolo Bombelli Christopher J. Howe Sabeeha S. Merchant Julia M. Davies Alison G. Smith 《Plant biotechnology journal》2016,14(1):22-28
Photosynthetic microbes exhibit light‐dependent electron export across the cell membrane, which can generate electricity in biological photovoltaic (BPV) devices. How electrons are exported remains to be determined; the identification of mechanisms would help selection or generation of photosynthetic microbes capable of enhanced electrical output. We show that plasma membrane NADPH oxidase activity is a significant component of light‐dependent generation of electricity by the unicellular green alga Chlamydomonas reinhardtii. NADPH oxidases export electrons across the plasma membrane to form superoxide anion from oxygen. The C. reinhardtii mutant lacking the NADPH oxidase encoded by RBO1 is impaired in both extracellular superoxide anion production and current generation in a BPV device. Complementation with the wild‐type gene restores both capacities, demonstrating the role of the enzyme in electron export. Monitoring light‐dependent extracellular superoxide production with a colorimetric assay is shown to be an effective way of screening for electrogenic potential of candidate algal strains. The results show that algal NADPH oxidases are important for superoxide anion production and open avenues for optimizing the biological component of these devices. 相似文献