scholarly journals Unique, Diverged, and Conserved Mitochondrial Functions InfluencingCandida albicansRespiration

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Nuo Sun ◽  
Rebecca S. Parrish ◽  
Richard A. Calderone ◽  
William A. Fonzi
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogen ◽  
Complex I ◽  
Electron Transport Chain ◽  
Complex Iii ◽  
Respiratory Metabolism ◽  
Content Type ◽  
Transport Chain ◽  
Opportunistic Fungal Pathogen ◽  
Lineage Specific Genes

ABSTRACTCandida albicansis an opportunistic fungal pathogen of major clinical concern. The virulence of this pathogen is intimately intertwined with its metabolism. Mitochondria, which have a central metabolic role, have undergone many lineage-specific adaptations in association with their eukaryotic host. A screen for lineage-specific genes identified seven such genes specific to the CTG clade of fungi, of whichC. albicansis a member. Each is required for respiratory growth and is integral to expression of complex I, III, or IV of the electron transport chain. Two genes,NUO3andNUO4, encode supernumerary subunits of complex I, whereasNUE1andNUE2have nonstructural roles in expression of complex I. Similarly, the other three genes have nonstructural roles in expression of complex III (QCE1) or complex IV (COE1andCOE2). In addition to these novel additions, an alternative functional assignment was found for the mitochondrial protein encoded byMNE1.MNE1was required for complex I expression inC. albicans, whereas the distantly relatedSaccharomyces cerevisiaeortholog participates in expression of complex III. Phenotypic analysis of deletion mutants showed that fermentative metabolism is unable to support optimal growth rates or yields ofC. albicans. However, yeast-hypha morphogenesis, an important virulence attribute, did not require respiratory metabolism under hypoxic conditions. The inability to respire also resulted in hypersensitivity to the antifungal fluconazole and in attenuated virulence in aGalleria mellonellainfection model. The results show that lineage-specific adaptations have occurred inC. albicansmitochondria and highlight the significance of respiratory metabolism in the pathobiology ofC. albicans.IMPORTANCECandida albicansis an opportunistic fungal pathogen of major clinical concern. The virulence of this pathogen is intimately intertwined with its metabolic behavior, and mitochondria have a central role in that metabolism. Mitochondria have undergone many evolutionary changes, which include lineage-specific adaptations in association with their eukaryotic host. Seven lineage-specific genes required for electron transport chain function were identified in the CTG clade of fungi, of whichC. albicansis a member. Additionally, examination of several highly diverged orthologs encoding mitochondrial proteins demonstrated functional reassignment for one of these. Deficits imparted by deletion of these genes revealed the critical role of respiration in virulence attributes of the fungus and highlight important evolutionary adaptations inC. albicansmetabolism.

scholarly journals High-Throughput Nano-Biofilm Microarray for Antifungal Drug Discovery

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Anand Srinivasan ◽  
Kai P. Leung ◽  
Jose L. Lopez-Ribot ◽  
Anand K. Ramasubramanian
Keyword(s):  
Cell Culture ◽  
Candida Albicans ◽  
Drug Discovery ◽  
High Throughput ◽  
Fungal Pathogen ◽  
Microarray Platform ◽  
Microbial Cell ◽  
Content Type ◽  
Petri Dishes ◽  
Opportunistic Fungal Pathogen

ABSTRACT Micro- and nanoscale technologies have radically transformed biological research from genomics to tissue engineering, with the relative exception of microbial cell culture, which is still largely performed in microtiter plates and petri dishes. Here, we present nanoscale culture of the opportunistic fungal pathogen Candida albicans on a microarray platform. The microarray consists of 1,200 individual cultures of 30 nl of C. albicans biofilms (“nano-biofilms”) encapsulated in an inert alginate matrix. We demonstrate that these nano-biofilms are similar to conventional macroscopic biofilms in their morphological, architectural, growth, and phenotypic characteristics. We also demonstrate that the nano-biofilm microarray is a robust and efficient tool for accelerating the drug discovery process: (i) combinatorial screening against a collection of 28 antifungal compounds in the presence of immunosuppressant FK506 (tacrolimus) identified six drugs that showed synergistic antifungal activity, and (ii) screening against the NCI challenge set small-molecule library identified three heretofore-unknown hits. This cell-based microarray platform allows for miniaturization of microbial cell culture and is fully compatible with other high-throughput screening technologies. IMPORTANCE Microorganisms are typically still grown in petri dishes, test tubes, and Erlenmeyer flasks in spite of the latest advances in miniaturization that have benefitted other allied research fields, including genomics and proteomics. Culturing microorganisms in small scale can be particularly valuable in cutting down time, cost, and reagent usage. This paper describes the development, characterization, and application of nanoscale culture of an opportunistic fungal pathogen, Candida albicans. Despite a more than 2,000-fold reduction in volume, the growth characteristics and drug response profiles obtained from the nanoscale cultures were comparable to the industry standards. The platform also enabled rapid identification of new drug candidates that were effective against C. albicans biofilms, which are a major cause of mortality in hospital-acquired infections.

scholarly journals Ascorbic Acid Inhibition of Candida albicans Hsp90-Mediated Morphogenesis Occurs via the Transcriptional Regulator Upc2

2014 ◽  
Vol 13 (10) ◽  
pp. 1278-1289 ◽  
Author(s):  
Frédérique Van Hauwenhuyse ◽  
Alessandro Fiori ◽  
Patrick Van Dijck
Keyword(s):  
Ascorbic Acid ◽  
Candida Albicans ◽  
Fungal Pathogen ◽  
Transcriptional Regulator ◽  
Hsp90 Inhibitor ◽  
Ergosterol Biosynthesis ◽  
Content Type ◽  
Temperature Changes ◽  
Opportunistic Fungal Pathogen ◽  
Hsp90 Function

ABSTRACTMorphogenetic transitions of the opportunistic fungal pathogenCandida albicansare influenced by temperature changes, with induction of filamentation upon a shift from 30 to 37°C. Hsp90 was identified as a major repressor of an elongated cell morphology at low temperatures, as treatment with specific inhibitors of Hsp90 results in elongated growth forms at 30°C. Elongated growth resulting from a compromised Hsp90 is considered neither hyphal nor pseudohyphal growth. It has been reported that ascorbic acid (vitamin C) interferes with the yeast-to-hypha transition inC. albicans. In the present study, we show that ascorbic acid also antagonizes the morphogenetic change caused by hampered Hsp90 function. Further analysis revealed that Upc2, a transcriptional regulator of genes involved in ergosterol biosynthesis, and Erg11, the target of azole antifungals, whose expression is in turn regulated by Upc2, are required for this antagonism. Ergosterol levels correlate with elongated growth and are reduced in cells treated with the Hsp90 inhibitor geldanamycin (GdA) and restored by cotreatment with ascorbic acid. In addition, we show that Upc2 appears to be required for ascorbic acid-mediated inhibition of the antifungal activity of fluconazole. These results identify Upc2 as a major regulator of ascorbic acid-induced effects inC. albicansand suggest an association between ergosterol content and elongated growth upon Hsp90 compromise.

Ischemic defects in the electron transport chain increase the production of reactive oxygen species from isolated rat heart mitochondria

2008 ◽  
Vol 294 (2) ◽  
pp. C460-C466 ◽  
Author(s):  
Qun Chen ◽  
Shadi Moghaddas ◽  
Charles L. Hoppel ◽  
Edward J. Lesnefsky
Keyword(s):  
Electron Transport ◽  
Complex I ◽  
Electron Transport Chain ◽  
Myocardial Injury ◽  
Complex Iii ◽  
Ischemic Damage ◽  
Ros Production ◽  
Oxygen Species ◽  
Net Production ◽  
Transport Chain

Cardiac ischemia decreases complex III activity, cytochrome c content, and respiration through cytochrome oxidase in subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). The reversible blockade of electron transport with amobarbital during ischemia protects mitochondrial respiration and decreases myocardial injury during reperfusion. These findings support that mitochondrial damage occurs during ischemia and contributes to myocardial injury during reperfusion. The current study addressed whether ischemic damage to the electron transport chain (ETC) increased the net production of reactive oxygen species (ROS) from mitochondria. SSM and IFM were isolated from 6-mo-old Fisher 344 rat hearts following 25 min global ischemia or following 40 min of perfusion alone as controls. H2O2release from SSM and IFM was measured using the amplex red assay. With glutamate as a complex I substrate, the net production of H2O2was increased by 178 ± 14% and 179 ± 17% in SSM and IFM ( n = 9), respectively, following ischemia compared with controls ( n = 8). With succinate as substrate in the presence of rotenone, H2O2increased by 272 ± 22% and 171 ± 21% in SSM and IFM, respectively, after ischemia. Inhibitors of electron transport were used to assess maximal ROS production. Inhibition of complex I with rotenone increased H2O2production by 179 ± 24% and 155 ± 14% in SSM and IFM, respectively, following ischemia. Ischemia also increased the antimycin A-stimulated production of H2O2from complex III. Thus ischemic damage to the ETC increased both the capacity and the net production of H2O2from complex I and complex III and sets the stage for an increase in ROS production during reperfusion as a mechanism of cardiac injury.

scholarly journals Insights into the Fundamental Physiology of the Uncultured Fe-Oxidizing BacteriumLeptothrix ochracea

2018 ◽  
Vol 84 (9) ◽  
Author(s):  
E. J. Fleming ◽  
T. Woyke ◽  
R. A. Donatello ◽  
M. M. M. Kuypers ◽  
A. Sczyrba ◽  
...  
Keyword(s):  
Electron Transport ◽  
Single Cell ◽  
Electron Transport Chain ◽  
Natural Waters ◽  
Iron Oxidation ◽  
Complex Iii ◽  
Total Carbon ◽  
Bisphosphate Carboxylase ◽  
Content Type ◽  
Transport Chain

ABSTRACTLeptothrix ochraceais known for producing large volumes of iron oxyhydroxide sheaths that alter wetland biogeochemistry. For over a century, these delicate structures have fascinated microbiologists and geoscientists. BecauseL. ochraceastill resists long-termin vitroculture, the debate regarding its metabolic classification dates back to 1885. We developed a novel culturing technique forL. ochraceausingin situnatural waters and coupled this with single-cell genomics and nanoscale secondary-ion mass spectrophotometry (nanoSIMS) to probeL. ochracea's physiology. In microslide culturesL. ochraceadoubled every 5.7 h and had an absolute growth requirement for ferrous iron, the genomic capacity for iron oxidation, and a branched electron transport chain with cytochromes putatively involved in lithotrophic iron oxidation. Additionally, its genome encoded several electron transport chain proteins, including a molybdopterin alternative complex III (ACIII), a cytochromebdoxidase reductase, and several terminal oxidase genes.L. ochraceacontained two key autotrophic proteins in the Calvin-Benson-Bassham cycle, a form II ribulose bisphosphate carboxylase, and a phosphoribulose kinase.L. ochraceaalso assimilated bicarbonate, although calculations suggest that bicarbonate assimilation is a small fraction of its total carbon assimilation. Finally,L. ochracea's fundamental physiology is a hybrid of those of the chemolithotrophicGallionella-type iron-oxidizing bacteria and the sheathed, heterotrophic filamentous metal-oxidizing bacteria of theLeptothrix-Sphaerotilusgenera. This allowsL. ochraceato inhabit a unique niche within the neutrophilic iron seeps.IMPORTANCELeptothrix ochraceawas one of three groups of organisms that Sergei Winogradsky used in the 1880s to develop his hypothesis on chemolithotrophy.L. ochraceacontinues to resist cultivation and appears to have an absolute requirement for organic-rich waters, suggesting that its true physiology remains unknown. Further,L. ochraceais an ecological engineer; a fewL. ochraceacells can generate prodigious volumes of iron oxyhydroxides, changing the ecosystem's geochemistry and ecology. Therefore, to determineL. ochracea's basic physiology, we employed new single-cell techniques to demonstrate thatL. ochraceaoxidizes iron to generate energy and, despite having predicted genes for autotrophic growth, assimilates a fraction of the total CO2that autotrophs do. Although not a true chemolithoautotroph,L. ochracea's physiological strategy allows it to be flexible and to extensively colonize iron-rich wetlands.

scholarly journals Control of Candida albicans Metabolism and Biofilm Formation by Pseudomonas aeruginosa Phenazines

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Diana K. Morales ◽  
Nora Grahl ◽  
Chinweike Okegbe ◽  
Lars E. P. Dietrich ◽  
Nicholas J. Jacobs ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Carbon Sources ◽  
Metabolic Effects ◽  
Respiratory Metabolism ◽  
Fermentation Products ◽  
Content Type ◽  
Opportunistic Fungal Pathogen ◽  
Biofilm Development

ABSTRACTCandida albicanshas developmental programs that govern transitions between yeast and filamentous morphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm development were inhibited during interactions betweenCandida albicansandPseudomonas aeruginosathrough the action ofP. aeruginosa-produced phenazines. While phenazines are toxic toC. albicansat millimolar concentrations, we found that lower concentrations of any of three different phenazines (pyocyanin, phenazine methosulfate, and phenazine-1-carboxylate) allowed growth but affected the development ofC. albicanswrinkled colony biofilms and inhibited the fungal yeast-to-filament transition. Phenazines impairedC. albicansgrowth on nonfermentable carbon sources and led to increased production of fermentation products (ethanol, glycerol, and acetate) in glucose-containing medium, leading us to propose that phenazines specifically inhibited respiration. Methylene blue, another inhibitor of respiration, also prevented the formation of structured colony biofilms. The inhibition of filamentation and colony wrinkling was not solely due to lowered extracellular pH induced by fermentation. Compared to smooth, unstructured colonies, wrinkled colony biofilms had higher oxygen concentrations within the colony, and wrinkled regions of these colonies had higher levels of respiration. Together, our data suggest that the structure of the fungal biofilm promotes access to oxygen and enhances respiratory metabolism and that the perturbation of respiration by bacterial molecules such as phenazines or compounds with similar activities disrupts these pathways. These findings may suggest new ways to limit fungal biofilms in the context of disease.IMPORTANCEMany of the infections caused byCandida albicans, a major human opportunistic fungal pathogen, involve both morphological transitions and the formation of surface-associated biofilms. Through the study ofC. albicansinteractions with the bacteriumPseudomonas aeruginosa, which often coinfects withC. albicans, we have found thatP. aeruginosa-produced phenazines modulateC. albicansmetabolism and, through these metabolic effects, impact cellular morphology, cell-cell interactions, and biofilm formation. We suggest that the structure ofC. albicansbiofilms promotes access to oxygen and enhances respiratory metabolism and that the perturbation of respiration by phenazines inhibits biofilm development. Our findings not only provide insight into interactions between these species but also provide valuable insights into novel pathways that could lead to the development of new therapies to treatC. albicansinfections.

scholarly journals Improved Gene Ontology Annotation for Biofilm Formation, Filamentous Growth, and Phenotypic Switching in Candida albicans

2012 ◽  
Vol 12 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Diane O. Inglis ◽  
Marek S. Skrzypek ◽  
Martha B. Arnaud ◽  
Jonathan Binkley ◽  
Prachi Shah ◽  
...  
Keyword(s):  
Gene Ontology ◽  
Candida Albicans ◽  
Gene Product ◽  
Fungal Pathogen ◽  
Biofilm Formation ◽  
Filamentous Growth ◽  
Phenotypic Switching ◽  
Gene Products ◽  
Content Type ◽  
Opportunistic Fungal Pathogen

ABSTRACTThe opportunistic fungal pathogenCandida albicansis a significant medical threat, especially for immunocompromised patients. Experimental research has focused on specific areas ofC. albicansbiology, with the goal of understanding the multiple factors that contribute to its pathogenic potential. Some of these factors include cell adhesion, invasive or filamentous growth, and the formation of drug-resistant biofilms. The Gene Ontology (GO) (www.geneontology.org) is a standardized vocabulary that theCandidaGenome Database (CGD) (www.candidagenome.org) and other groups use to describe the functions of gene products. To improve the breadth and accuracy of pathogenicity-related gene product descriptions and to facilitate the description of as yet uncharacterized but potentially pathogenicity-related genes inCandidaspecies, CGD undertook a three-part project: first, the addition of terms to the biological process branch of the GO to improve the description of fungus-related processes; second, manual recuration of gene product annotations in CGD to use the improved GO vocabulary; and third, computational ortholog-based transfer of GO annotations from experimentally characterized gene products, using these new terms, to uncharacterized orthologs in otherCandidaspecies. Through genome annotation and analysis, we identified candidate pathogenicity genes in seven non-C. albicans Candidaspecies and in one additionalC. albicansstrain, WO-1. We also defined a set ofC. albicansgenes at the intersection of biofilm formation, filamentous growth, pathogenesis, and phenotypic switching of this opportunistic fungal pathogen, which provides a compelling list of candidates for further experimentation.

scholarly journals Candida albicans ENT2 Contributes to Efficient Endocytosis, Cell Wall Integrity, Filamentation, and Virulence

mSphere ◽  
2021 ◽  
Author(s):  
Christiane Rollenhagen ◽  
Harrison Agyeman ◽  
Susan Eszterhas ◽  
Samuel A. Lee
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Fungal Pathogen ◽  
Clinical Importance ◽  
Hospitalized Patients ◽  
Cell Wall Integrity ◽  
Content Type ◽  
Invasive Infections ◽  
Opportunistic Fungal Pathogen ◽  
Considerable Morbidity

The opportunistic fungal pathogen Candida albicans is an important cause of invasive infections in hospitalized patients and a source of considerable morbidity and mortality. Despite its clinical importance, we still need to improve our ability to diagnose and treat this common pathogen.

scholarly journals Rieske head domain dynamics and indazole-derivative inhibition of Candida albicans complex III

2021 ◽  
Author(s):  
Justin Di Trani ◽  
Zhongle Liu ◽  
Luke Whitesell ◽  
Peter Brzezinski ◽  
Leah Cowen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Transport Processes ◽  
Complex Iii ◽  
Cellular Respiration ◽  
Inner Mitochondrial Membrane ◽  
Head Domain ◽  
Q Cycle ◽  
Transport Chain

During cellular respiration, electron transfer between the integral membrane protein complexes of the electron transport chain is coupled to proton translocation across the inner mitochondrial membrane, which in turn powers synthesis of ATP and transmembrane transport processes. The homodimeric electron transport chain Complex III (CIII2) oxidizes ubiquinol (UQH2) to ubiquinone (UQ), transferring electrons to cytochrome c, and translocating protons through a mechanism known as the Q cycle. The Q cycle involves UQH2 oxidation and UQ reduction at two different sites within each CIII monomer, as well as movement of the head domain of the Rieske subunit. We used cryoEM to determine the structure of CIII2 from Candida albicans, revealing density for endogenous UQ in the structure and allowing us to directly visualize the continuum of conformations of the Rieske head domain. Analysis of these conformations does not indicate cooperativity in the position of the Rieske head domains or binding of ligands in the two CIIIs of the CIII2 dimer. CryoEM with the indazole derivative Inz-5, which inhibits fungal CIII2 and is fungicidal when administered with fungistatic azole drugs, showed that inhibition by Inz-5 alters the equilibrium of the Rieske head domain positions.

scholarly journals Targeting the complex I and III of mitochondrial electron transport chain as a potentially viable option in liver cancer management

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Qin Yang ◽  
Ling Wang ◽  
Jiaye Liu ◽  
Wanlu Cao ◽  
Qiuwei Pan ◽  
...  
Keyword(s):  
Electron Transport ◽  
Liver Cancer ◽  
Therapeutic Target ◽  
Complex I ◽  
Electron Transport Chain ◽  
Metabolic Reprogramming ◽  
Complex Iii ◽  
Mitochondrial Electron Transport Chain ◽  
Potential Therapeutic Target ◽  
Transport Chain

AbstractLiver cancer is one of the most common and lethal types of oncological disease in the world, with limited treatment options. New treatment modalities are desperately needed, but their development is hampered by a lack of insight into the underlying molecular mechanisms of disease. It is clear that metabolic reprogramming in mitochondrial function is intimately linked to the liver cancer process, prompting the possibility to explore mitochondrial biochemistry as a potential therapeutic target. Here we report that depletion of mitochondrial DNA, pharmacologic inhibition of mitochondrial electron transport chain (mETC) complex I/complex III, or genetic of mETC complex I restricts cancer cell growth and clonogenicity in various preclinical models of liver cancer, including cell lines, mouse liver organoids, and murine xenografts. The restriction is linked to the production of reactive oxygen species, apoptosis induction and reduced ATP generation. As a result, our findings suggest that the mETC compartment of mitochondria could be a potential therapeutic target in liver cancer.

scholarly journals New Mitochondrial Targets in Fungal Pathogens

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Daniel Murante ◽  
Deborah A. Hogan
Keyword(s):  
Electron Transport Chain ◽  
Fungal Pathogens ◽  
Phylogenetic Group ◽  
Eukaryotic Cells ◽  
Respiratory Metabolism ◽  
Human Pathogens ◽  
Model Species ◽  
Content Type ◽  
Transport Chain ◽  
Microbiological Assays

ABSTRACT In eukaryotic cells, mitochondria are responsible for the synthesis of ATP using power generated by the electron transport chain (ETC). While much of what is known about mitochondria has been gained from a study of a small number of model species, including the yeast Saccharomyces cerevisiae, the general mechanisms of mitochondrial respiration have been recognized as being highly conserved across eukaryotes. Now, Sun et al. (N. Sun, R. S. Parrish, R. A. Calderone, and W. A. Fonzi, mBio 10:e00300-19, 2019, https://doi.org/10.1128/mBio.00300-19) take the next steps in understanding mitochondrial function by identifying proteins that are unique to a smaller phylogenetic group of microbes. Using the combination of in silico, biochemical, and microbiological assays, Sun and colleagues identified seven genes that are unique to the CTG fungal clade, which contains multiple important human pathogens, including Candida albicans, and showed that they are required for full ETC function during respiratory metabolism. Because respiratory metabolism is critical for fungal pathogenesis, these clade-specific mitochondrial factors may represent novel therapeutic targets.

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