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Sample records for albicans regulates hyphal

  1. The Candida albicans-specific gene EED1 encodes a key regulator of hyphal extension.

    LENUS (Irish Health Repository)

    Martin, Ronny

    2011-04-01

    The extension of germ tubes into elongated hyphae by Candida albicans is essential for damage of host cells. The C. albicans-specific gene EED1 plays a crucial role in this extension and maintenance of filamentous growth. eed1Δ cells failed to extend germ tubes into long filaments and switched back to yeast growth after 3 h of incubation during growth on plastic surfaces. Expression of EED1 is regulated by the transcription factor Efg1 and ectopic overexpression of EED1 restored filamentation in efg1Δ. Transcriptional profiling of eed1Δ during infection of oral tissue revealed down-regulation of hyphal associated genes including UME6, encoding another key transcriptional factor. Ectopic overexpression of EED1 or UME6 rescued filamentation and damage potential in eed1Δ. Transcriptional profiling during overexpression of UME6 identified subsets of genes regulated by Eed1 or Ume6. These data suggest that Eed1 and Ume6 act in a pathway regulating maintenance of hyphal growth thereby repressing hyphal-to-yeast transition and permitting dissemination of C. albicans within epithelial tissues.

  2. Hbr1 Activates and Represses Hyphal Growth in Candida albicans and Regulates Fungal Morphogenesis under Embedded Conditions

    OpenAIRE

    Pendrak, Michael L.; Roberts, David D.

    2015-01-01

    Transitions between yeast and hyphae are essential for Candida albicans pathogenesis. The genetic programs that regulate its hyphal development can be distinguished by embedded versus aerobic surface agar invasion. Hbr1, a regulator of white-opaque switching, is also a positive and negative regulator of hyphal invasion. During embedded growth at 24°C, an HBR1/hbr1 strain formed constitutively filamentous colonies throughout the matrix, resembling EFG1 null colonies, and a subset of long unbra...

  3. A Global Analysis of Kinase Function in Candida albicans Hyphal Morphogenesis Reveals a Role for the Endocytosis Regulator Akl1

    Directory of Open Access Journals (Sweden)

    Hagit Bar-Yosef

    2018-02-01

    Full Text Available The human pathogenic fungus Candida albicans can switch between yeast and hyphal morphologies as a function of environmental conditions and cellular physiology. The yeast-to-hyphae morphogenetic switch is activated by well-established, kinase-based signal transduction pathways that are induced by extracellular stimuli. In order to identify possible inhibitory pathways of the yeast-to-hyphae transition, we interrogated a collection of C. albicans protein kinases and phosphatases ectopically expressed under the regulation of the TETon promoter. Proportionately more phosphatases than kinases were identified that inhibited hyphal morphogenesis, consistent with the known role of protein phosphorylation in hyphal induction. Among the kinases, we identified AKL1 as a gene that significantly suppressed hyphal morphogenesis in serum. Akl1 specifically affected hyphal elongation rather than initiation: overexpression of AKL1 repressed hyphal growth, and deletion of AKL1 resulted in acceleration of the rate of hyphal elongation. Akl1 suppressed fluid-phase endocytosis, probably via Pan1, a putative clathrin-mediated endocytosis scaffolding protein. In the absence of Akl1, the Pan1 patches were delocalized from the sub-apical region, and fluid-phase endocytosis was intensified. These results underscore the requirement of an active endocytic pathway for hyphal morphogenesis. Furthermore, these results suggest that under standard conditions, endocytosis is rate-limiting for hyphal elongation.

  4. Candida albicans hyphal invasion: thigmotropism or chemotropism?

    Science.gov (United States)

    Davies, J M; Stacey, A J; Gilligan, C A

    1999-02-15

    Hyphae of the human pathogenic fungus Candida albicans exhibit thigmotropic behaviour in vitro, in common with phytopathogenic and saprotrophic fungi. An examination of the literature on C. albicans hyphal penetration of epithelial and endothelial membranes does not support the premise that hyphal thigmotropism plays a major role in tissue invasion. Further experimentation is now required to assess thigmotropic behaviour on host membranes and vaginal epithelial cells are suggested as a test model. It is proposed that while thigmotropism may and invasion of tissue invaginations, chemotropism can explain C. albicans hyphal invasion patterns of both endothelium and epithelium.

  5. Hyphal orientation of Candida albicans is regulated by a calcium-dependent mechanism.

    Science.gov (United States)

    Brand, Alexandra; Shanks, Scott; Duncan, Vanessa M S; Yang, Meng; Mackenzie, Kevin; Gow, Neil A R

    2007-02-20

    Eukaryotic cells from fungal hyphae to neurites that grow by polarized extension must coordinate cell growth and cell orientation to enable them to exhibit growth tropisms and to respond to relevant environmental cues. Such cells generally maintain a tip-high Ca(2+) cytoplasmic gradient, which is correlated with their ability to exhibit polarized tip growth and to respond to growth-directing extracellular signals. In yeast and other fungi, the polarisome, exocyst, Arp2/3, and Spitzenkörper protein complexes collectively orchestrate tip growth and cell polarity, but it is not clear whether these molecular complexes also regulate cell orientation or whether they are influenced by cytoplasmic Ca(2+) gradients. Hyphae of the human pathogenic fungus Candida albicans reorient their growth axis in response to underlying surface topography (thigmotropism) and imposed electric fields (galvanotropism). The establishment and maintenance of directional growth in relation to these environmental cues was Ca(2+) dependent. Tropisms were attenuated in media containing low Ca(2+), or calcium-channel blockers, and in mutants where calcium channels or elements of the calcium signaling pathway were deleted. Therefore galvanotropism and thigmotropism may both be mediated by localized Ca(2+) influx at sites of polarized growth via Ca(2+) channels that are activated by appropriate environmental signals.

  6. Purpurin suppresses Candida albicans biofilm formation and hyphal development.

    Directory of Open Access Journals (Sweden)

    Paul Wai-Kei Tsang

    Full Text Available A striking and clinically relevant virulence trait of the human fungal pathogen Candida albicans is its ability to grow and switch reversibly among different morphological forms. Inhibition of yeast-to-hypha transition in C. albicans represents a new paradigm for antifungal intervention. We have previously demonstrated the novel antifungal activity of purpurin against Candida fungi. In this study, we extended our investigation by examining the in vitro effect of purpurin on C. albicans morphogenesis and biofilms. The susceptibility of C. albicans biofilms to purpurin was examined quantitatively by 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl-2H-tetrazolium-5-carboxanilide reduction assay. Hyphal formation and biofilm ultrastructure were examined qualitatively by scanning electron microscopy (SEM. Quantitative reverse transcription-PCR (qRT-PCR was used to evaluate the expression of hypha-specific genes and hyphal regulator in purpurin-treated fungal cells. The results showed that, at sub-lethal concentration (3 µg/ml, purpurin blocked the yeast-to-hypha transition under hypha-inducing conditions. Purpurin also inhibited C. albicans biofilm formation and reduced the metabolic activity of mature biofilms in a concentration-dependent manner. SEM images showed that purpurin-treated C. albicans biofilms were scanty and exclusively consisted of aggregates of blastospores. qRT-PCR analyses indicated that purpurin downregulated the expression of hypha-specific genes (ALS3, ECE1, HWP1, HYR1 and the hyphal regulator RAS1. The data strongly suggested that purpurin suppressed C. albicans morphogenesis and caused distorted biofilm formation. By virtue of the ability to block these two virulence traits in C. albicans, purpurin may represent a potential candidate that deserves further investigations in the development of antifungal strategies against this notorious human fungal pathogen in vivo.

  7. Integration of the tricarboxylic acid (TCA) cycle with cAMP signaling and Sfl2 pathways in the regulation of CO2 sensing and hyphal development in Candida albicans.

    Science.gov (United States)

    Tao, Li; Zhang, Yulong; Fan, Shuru; Nobile, Clarissa J; Guan, Guobo; Huang, Guanghua

    2017-08-01

    Morphological transitions and metabolic regulation are critical for the human fungal pathogen Candida albicans to adapt to the changing host environment. In this study, we generated a library of central metabolic pathway mutants in the tricarboxylic acid (TCA) cycle, and investigated the functional consequences of these gene deletions on C. albicans biology. Inactivation of the TCA cycle impairs the ability of C. albicans to utilize non-fermentable carbon sources and dramatically attenuates cell growth rates under several culture conditions. By integrating the Ras1-cAMP signaling pathway and the heat shock factor-type transcription regulator Sfl2, we found that the TCA cycle plays fundamental roles in the regulation of CO2 sensing and hyphal development. The TCA cycle and cAMP signaling pathways coordinately regulate hyphal growth through the molecular linkers ATP and CO2. Inactivation of the TCA cycle leads to lowered intracellular ATP and cAMP levels and thus affects the activation of the Ras1-regulated cAMP signaling pathway. In turn, the Ras1-cAMP signaling pathway controls the TCA cycle through both Efg1- and Sfl2-mediated transcriptional regulation in response to elevated CO2 levels. The protein kinase A (PKA) catalytic subunit Tpk1, but not Tpk2, may play a major role in this regulation. Sfl2 specifically binds to several TCA cycle and hypha-associated genes under high CO2 conditions. Global transcriptional profiling experiments indicate that Sfl2 is indeed required for the gene expression changes occurring in response to these elevated CO2 levels. Our study reveals the regulatory role of the TCA cycle in CO2 sensing and hyphal development and establishes a novel link between the TCA cycle and Ras1-cAMP signaling pathways.

  8. Integration of the tricarboxylic acid (TCA cycle with cAMP signaling and Sfl2 pathways in the regulation of CO2 sensing and hyphal development in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Li Tao

    2017-08-01

    Full Text Available Morphological transitions and metabolic regulation are critical for the human fungal pathogen Candida albicans to adapt to the changing host environment. In this study, we generated a library of central metabolic pathway mutants in the tricarboxylic acid (TCA cycle, and investigated the functional consequences of these gene deletions on C. albicans biology. Inactivation of the TCA cycle impairs the ability of C. albicans to utilize non-fermentable carbon sources and dramatically attenuates cell growth rates under several culture conditions. By integrating the Ras1-cAMP signaling pathway and the heat shock factor-type transcription regulator Sfl2, we found that the TCA cycle plays fundamental roles in the regulation of CO2 sensing and hyphal development. The TCA cycle and cAMP signaling pathways coordinately regulate hyphal growth through the molecular linkers ATP and CO2. Inactivation of the TCA cycle leads to lowered intracellular ATP and cAMP levels and thus affects the activation of the Ras1-regulated cAMP signaling pathway. In turn, the Ras1-cAMP signaling pathway controls the TCA cycle through both Efg1- and Sfl2-mediated transcriptional regulation in response to elevated CO2 levels. The protein kinase A (PKA catalytic subunit Tpk1, but not Tpk2, may play a major role in this regulation. Sfl2 specifically binds to several TCA cycle and hypha-associated genes under high CO2 conditions. Global transcriptional profiling experiments indicate that Sfl2 is indeed required for the gene expression changes occurring in response to these elevated CO2 levels. Our study reveals the regulatory role of the TCA cycle in CO2 sensing and hyphal development and establishes a novel link between the TCA cycle and Ras1-cAMP signaling pathways.

  9. Hyphal formation of Candida albicans is controlled by electron transfer system

    International Nuclear Information System (INIS)

    Watanabe, Toshihiko; Ogasawara, Ayako; Mikami, Takeshi; Matsumoto, Tatsuji

    2006-01-01

    Most Candida albicans cells cultured in RPMI1640 medium at 37 deg. C grow in hyphal form in aerobic conditions, but they grow in yeast form in anaerobic conditions. The hyphal growth of C. albicans was inhibited in glucose-deficient conditions. Malonic acid, an inhibitor of succinate dehydrogenase, enhanced the yeast proliferation of C. albicans, indicating that the hyphal-formation signal was derived from the glycolysis system and the signal was transmitted to the electron transfer system via the citric acid cycle. Thenoyl trifluoro acetone (TTFA), an inhibitor of the signal transmission between complex II and Co Q, significantly inhibited the hyphal growth of C. albicans. Antimycin, KCN, and oligomycin, inhibitors of complex III, IV, and V, respectively, did not inhibit the hyphal growth of C. albicans. The production of mRNAs for the hyphal formation signal was completely inhibited in anaerobic conditions. These results indicate that the electron transfer system functions upstream of the RAS1 signal pathway and activates the expression of the hyphal formation signal. Since the electron transfer system is inactivated in anaerobic conditions, C. albicans grew in yeast form in this condition

  10. [Rbf1 (RPG-box binding factor), a transcription factor involved in yeast-hyphal transition of Candida albicans].

    Science.gov (United States)

    Aoki, Y; Ishii, N; Watanabe, M; Yoshihara, F; Arisawa, M

    1998-01-01

    The major fungal pathogen for fungal diseases which have become a major medical problem in the last few years is Candida albicans, which can grow both in yeast and hyphae forms. This ability of C. albicans is thought to contribute to its colonization and dissemination within host tissues. In a recent few years, accompanying the introduction of molecular biological tools into C. albicans organism, several factors involved in the signal transduction pathway for yeast-hyphal transition have been identified. One MAP kinase pathway in C. albicans, similar to that leading to STE12 activation in Saccharomyces cerevisiae, has been reported. C. albicans strains mutant in these genes show retarded filamentous growth on a solid media but no impairment of filamentous growth in mice. These results suggest two scenarios that a kinase signaling cascade plays a part in stimulating the morphological transition in C. albicans, and that there would be another signaling pathway effective in animals. In this latter true hyphal pathway, although some candidate proteins, such as Efg1 (transcription factor), Int1 (integrin-like membrane protein), or Phr1 (pH-regulated membrane protein), have been identified, it is still too early to say that we understand the whole picture of that cascade. We have cloned a C. albicans gene encoding a novel DNA binding protein, Rbf1, that predominantly localizes in the nucleus, and shows transcriptional activation capability. Disruption of the functional RBF1 genes of C. albicans induced the filamentous growth on all solid and liquid media tested, suggesting that Rbf1 might be another candidate for the true hyphal pathway. Relationships with other factors described above, and the target (regulated) genes of Rbf1 is under investigation.

  11. Systemic Staphylococcus aureus infection mediated by Candida albicans hyphal invasion of mucosal tissue

    NARCIS (Netherlands)

    Schlecht, L.M.; Peters, B.M.; Krom, B.P.; Freiberg, J.A.; Hänsch, G.M.; Filler, S.G.; Jabra-Rizk, M.A.; Shirtliff, M.E.

    2015-01-01

    Candida albicans and Staphylococcus aureus are often co-isolated in cases of biofilm-associated infections. C. albicans can cause systemic disease through morphological switch from the rounded yeast to the invasive hyphal form. Alternatively, systemic S. aureus infections arise from seeding through

  12. An internal polarity landmark is important for externally induced hyphal behaviors in Candida albicans.

    Science.gov (United States)

    Brand, Alexandra; Vacharaksa, Anjalee; Bendel, Catherine; Norton, Jennifer; Haynes, Paula; Henry-Stanley, Michelle; Wells, Carol; Ross, Karen; Gow, Neil A R; Gale, Cheryl A

    2008-04-01

    Directional growth is a function of polarized cells such as neurites, pollen tubes, and fungal hyphae. Correct orientation of the extending cell tip depends on signaling pathways and effectors that mediate asymmetric responses to specific environmental cues. In the hyphal form of the eukaryotic fungal pathogen Candida albicans, these responses include thigmotropism and galvanotropism (hyphal turning in response to changes in substrate topography and imposed electrical fields, respectively) and penetration into semisolid substrates. During vegetative growth in C. albicans, as in the model yeast Saccharomyces cerevisiae, the Ras-like GTPase Rsr1 mediates internal cellular cues to position new buds in a prespecified pattern on the mother cell cortex. Here, we demonstrate that Rsr1 is also important for hyphal tip orientation in response to the external environmental cues that induce thigmotropic and galvanotropic growth. In addition, Rsr1 is involved in hyphal interactions with epithelial cells in vitro and its deletion diminishes the hyphal invasion of kidney tissue during systemic infection. Thus, Rsr1, an internal polarity landmark in yeast, is also involved in polarized growth responses to asymmetric environmental signals, a paradigm that is different from that described for the homologous protein in S. cerevisiae. Rsr1 may thereby contribute to the pathogenesis of C. albicans infections by influencing hyphal tip responses triggered by interaction with host tissues.

  13. The mating projections of Saccharomyces cerevisiae and Candida albicans show key characteristics of hyphal growth.

    Science.gov (United States)

    Chapa-Y-Lazo, Bernardo; Lee, Sheu; Regan, Hannah; Sudbery, Peter

    2011-06-01

    Fungi can grow in a variety of growth forms: yeast, pseudohyphae and hyphae. The human fungal pathogen Candida albicans can grow in all three of these forms. In this fungus, hyphal growth is distinguished by the presence of a Spitzenkörper-like structure at the hyphal tip and a band of septin bars around the base of newly evaginated germ tubes. The budding yeast Saccharomyces cerevisiae grows as yeast and pseudohyphae, but is not normally considered to show hyphal growth. We show here that in mating projections of both C. albicans and S. cerevisiae a Spitzenkörper-like structure is present at the growing tip and a band of septin bars is present at the base. Furthermore, in S. cerevisiae mating projections, Spa2 and Bni1 form a cap to the 3-dimensional ball of FM4-64 staining, exactly as previously observed in C. albicans hyphae, suggesting that the putative Spitzenkörper may be a distinct structure from the polarisome. Taken together this work shows that mating projections of both S. cerevisiae and C. albicans show the key characteristics of hyphal growth. Copyright © 2011 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  14. Post-translational modification directs nuclear and hyphal tip localization of Candida albicans mRNA-binding protein Slr1.

    Science.gov (United States)

    Ariyachet, Chaiyaboot; Beißel, Christian; Li, Xiang; Lorrey, Selena; Mackenzie, Olivia; Martin, Patrick M; O'Brien, Katharine; Pholcharee, Tossapol; Sim, Sue; Krebber, Heike; McBride, Anne E

    2017-05-01

    The morphological transition of the opportunistic fungal pathogen Candida albicans from budding to hyphal growth has been implicated in its ability to cause disease in animal models. Absence of SR-like RNA-binding protein Slr1 slows hyphal formation and decreases virulence in a systemic candidiasis model, suggesting a role for post-transcriptional regulation in these processes. SR (serine-arginine)-rich proteins influence multiple steps in mRNA metabolism and their localization and function are frequently controlled by modification. We now demonstrate that Slr1 binds to polyadenylated RNA and that its intracellular localization is modulated by phosphorylation and methylation. Wildtype Slr1-GFP is predominantly nuclear, but also co-fractionates with translating ribosomes. The non-phosphorylatable slr1-6SA-GFP protein, in which six serines in SR/RS clusters are substituted with alanines, primarily localizes to the cytoplasm in budding cells. Intriguingly, hyphal cells display a slr1-6SA-GFP focus at the tip near the Spitzenkörper, a vesicular structure involved in molecular trafficking to the tip. The presence of slr1-6SA-GFP hyphal tip foci is reduced in the absence of the mRNA-transport protein She3, suggesting that unphosphorylated Slr1 associates with mRNA-protein complexes transported to the tip. The impact of SLR1 deletion on hyphal formation and function thus may be partially due to a role in hyphal mRNA transport. © 2017 John Wiley & Sons Ltd.

  15. Hyphal content determines the compression strength of Candida albicans biofilms

    NARCIS (Netherlands)

    Paramonova, Ekaterina; Krom, Bastiaan P.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

    Candida albicans is the most frequently isolated human fungal pathogen among species causing biofilm-related clinical infections. Mechanical properties of Candida biofilms have hitherto been given no attention, despite the fact that mechanical properties are important for selection of treatment or

  16. Proteus vulgaris and Proteus mirabilis Decrease Candida albicans Biofilm Formation by Suppressing Morphological Transition to Its Hyphal Form.

    Science.gov (United States)

    Lee, Kyoung Ho; Park, Su Jung; Choi, Sun Ju; Park, Joo Young

    2017-11-01

    Candida albicans (C. albicans) and Proteus species are causative agents in a variety of opportunistic nosocomial infections, and their ability to form biofilms is known to be a virulence factor. In this study, the influence of co-cultivation with Proteus vulgaris (P. vulgaris) and Proteus mirabilis (P. mirabilis) on C. albicans biofilm formation and its underlying mechanisms were examined. XTT reduction assays were adopted to measure biofilm formation, and viable colony counts were performed to quantify yeast growth. Real-time reverse transcriptase polymerase chain reaction was used to evaluate the expression of yeast-specific genes (rhd1 and rbe1), filament formation inhibiting genes (tup1 and nrg1), and hyphae-related genes (als3, ece1, hwp1, and sap5). Candida biofilm formation was markedly inhibited by treatment with either living or heat-killed P. vulgaris and P. mirabilis. Proteus-cultured supernatant also inhibited Candida biofilm formation. Likewise, treatment with live P. vulgaris or P. mirabilis or with Proteus-cultured supernatant decreased expression of hyphae-related C. albicans genes, while the expression of yeast-specific genes and the filament formation inhibiting genes of C. albicans were increased. Heat-killed P. vulgaris and P. mirabilis treatment, however, did not affect the expression of C. albicans morphology-related genes. These results suggest that secretory products from P. vulgaris and P. mirabilis regulate the expression of genes related to morphologic changes in C. albicans such that transition from the yeast form to the hyphal form can be inhibited. © Copyright: Yonsei University College of Medicine 2017

  17. Inhibitory effects of the essential oils α-longipinene and linalool on biofilm formation and hyphal growth of Candida albicans.

    Science.gov (United States)

    Manoharan, Ranjith Kumar; Lee, Jin-Hyung; Kim, Yong-Guy; Kim, Soon-Il; Lee, Jintae

    2017-02-01

    Candida albicans is one of the most common fungal pathogens, and causes systemic and invasive infections in humans. C. albicans biofilms are composed of yeast and hyphal and pseudohyphal elements, and the transition of yeast to the hyphal stage could be a virulence factor. In this study, diverse essential oils were initially investigated for anti-biofilm activity against C. albicans strains, and cascarilla bark oil and helichrysum oil and their components α-longipinene (a major constituent of both) and linalool were found to markedly inhibit biofilm formation without affecting planktonic cell growth. Moreover, α-longipinene and linalool were found to synergistically reduce biofilm formation. Notably, treatments with cascarilla bark oil, helichrysum oil, α-longipinene, or linalool clearly inhibited hyphal formation, and this appeared to be largely responsible for their anti-biofilm effect. Furthermore, the two essential oils, α-longipinene and linalool, reduced C. albicans virulence in Caenorhabditis elegans.

  18. Niche-Specific Requirement for Hyphal Wall protein 1 in Virulence of Candida albicans

    Science.gov (United States)

    Staab, Janet F.; Datta, Kausik; Rhee, Peter

    2013-01-01

    Specialized Candida albicans cell surface proteins called adhesins mediate binding of the fungus to host cells. The mammalian transglutaminase (TG) substrate and adhesin, Hyphal wall protein 1 (Hwp1), is expressed on the hyphal form of C. albicans where it mediates fungal adhesion to epithelial cells. Hwp1 is also required for biofilm formation and mating thus the protein functions in both fungal-host and self-interactions. Hwp1 is required for full virulence of C. albicans in murine models of disseminated candidiasis and of esophageal candidiasis. Previous studies correlated TG activity on the surface of oral epithelial cells, produced by epithelial TG (TG1), with tight binding of C. albicans via Hwp1 to the host cell surfaces. However, the contribution of other Tgs, specifically tissue TG (TG2), to disseminated candidiasis mediated by Hwp1 was not known. A newly created hwp1 null strain in the wild type SC5314 background was as virulent as the parental strain in C57BL/6 mice, and virulence was retained in C57BL/6 mice deleted for Tgm2 (TG2). Further, the hwp1 null strains displayed modestly reduced virulence in BALB/c mice as did strain DD27-U1, an independently created hwp1Δ/Δ in CAI4 corrected for its ura3Δ defect at the URA3 locus. Hwp1 was still needed to produce wild type biofilms, and persist on murine tongues in an oral model of oropharyngeal candidiasis consistent with previous studies by us and others. Finally, lack of Hwp1 affected the translocation of C. albicans from the mouse intestine into the bloodstream of mice. Together, Hwp1 appears to have a minor role in disseminated candidiasis, independent of tissue TG, but a key function in host- and self-association to the surface of oral mucosa. PMID:24260489

  19. The AAA ATPase Vps4 Plays Important Roles in Candida albicans Hyphal Formation and is Inhibited by DBeQ.

    Science.gov (United States)

    Zhang, Yahui; Li, Wanjie; Chu, Mi; Chen, Hengye; Yu, Haoyuan; Fang, Chaoguang; Sun, Ningze; Wang, Qiming; Luo, Tian; Luo, Kaiju; She, Xueping; Zhang, Mengqian; Yang, Dong

    2016-06-01

    Candida albicans is an opportunistic human pathogen, and its pathogenicity is associated with hyphal formation. Previous studies have shown that at neutral-to-alkaline pH, hyphal growth is dependent on the Rim101 pathway whose activation requires Snf7, a member of the ESCRT system. In this work, we described the purification and characterization of the C. albicans Vps4, an AAA ATPase required for recycling of the ESCRTs. Its role on hyphal growth has been investigated. Our data suggest deletion of Vps4 decreases overall hyphal growth at pH 7 and increases the growth of multiple hyphae induced by serum, which indicates that the ESCRTs may make a Rim101-independent contribution to hyphal growth. Furthermore, DBeQ, an inhibitor of the AAA ATPase p97, was shown to inhibit the ATPase activity of Vps4 with an IC50 of about 11.5 μM. To a less degree, it also inhibits hyphal growth. Our work may provide a new strategy to control C. albicans infection.

  20. Candida albicans: The Ability to Invade Epithelial Cells and Survive under Oxidative Stress Is Unlinked to Hyphal Length

    Directory of Open Access Journals (Sweden)

    Paloma K. Maza

    2017-07-01

    Full Text Available In its hyphal form, Candida albicans invades epithelial and endothelial cells by two distinct mechanisms: active penetration and induced endocytosis. The latter is dependent on a reorganization of the host cytoskeleton (actin/cortactin recruitment, whilst active penetration does not rely on the host's cellular machinery. The first obstacle for the fungus to reach deep tissues is the epithelial barrier and this interaction is crucial for commensal growth, fungal pathogenicity and host defense. This study aimed to characterize in vitro epithelial HeLa cell invasion by four different isolates of C. albicans with distinct clinical backgrounds, including a C. albicans SC5314 reference strain. All isolates invaded HeLa cells, recruited actin and cortactin, and induced the phosphorylation of both Src-family kinases (SFK and cortactin. Curiously, L3881 isolated from blood culture of a patient exhibited the highest resistance to oxidative stress, although this isolate showed reduced hyphal length and displayed the lowest cell damage and invasion rates. Collectively, these data suggest that the ability of C. albicans to invade HeLa cells, and to reach and adapt to the host's blood, including resistance to oxidative stress, may be independent of hyphal length.

  1. Rax2 is important for directional establishment of growth sites, but not for reorientation of growth axes, during Candida albicans hyphal morphogenesis.

    Science.gov (United States)

    Gonia, Sara; Norton, Jennifer; Watanaskul, Lindy; Pulver, Rebecca; Morrison, Emma; Brand, Alexandra; Gale, Cheryl A

    2013-07-01

    Hyphae of filamentous fungi maintain generally linear growth over long distances. In Candida albicans, hyphae are able to reorient their growth in the direction of certain environmental cues. In previous work, the C. albicans bud-site selection proteins Rsr1 and Bud2 were identified as important for hyphae to maintain linear growth and were necessary for hyphal responses to directional cues in the environment (tropisms). To ask if hyphal directional responses are general functions of all yeast bud-site selection proteins, we studied the role of Rax2, ortholog of the Saccharomyces cerevisiae bud-site selection protein Rax2, in C. albicans hyphal morphogenesis. Rax2-YFP localized to the hyphal cell surface in puncta and at the hyphal tip in a crescent. Strains lacking Rax2 had hyphal morphologies that did not differ from control strains. In non-cued growth conditions, rax2 mutant strains had defects in both yeast (bud) and hyphal (branch) site selection and mutant hyphae exhibited non-linear growth trajectories as compared to control hyphae. In contrast, when encountering a directional environmental cue, hyphae lacking Rax2 retained the ability to reorient growth in response to both topographical (thigmotropism) and electric-field (galvanotropism) stimuli but exhibited a reduced ability to establish hyphal growth in the direction of a cathodal stimulus. In conclusion, these results indicate that C. albicans Rax2 is important for establishing sites of emergence of yeast and hyphal daughters and for maintaining the linearity of hyphal growth. In contrast to Rsr1 and Bud2, Rax2 is not involved in responses that require a reorientation of the direction of already established hyphal growth (tropisms). Thus, it appears that some hyphal directionality responses are separable in that they are mediated by a different set of polarity proteins. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Effects of extracellular DNA from Candida albicans and pneumonia-related pathogens on Candida biofilm formation and hyphal transformation.

    Science.gov (United States)

    Sapaar, B; Nur, A; Hirota, K; Yumoto, H; Murakami, K; Amoh, T; Matsuo, T; Ichikawa, T; Miyake, Y

    2014-06-01

    The aim of this study was to investigate the effects of genomic DNA purified from Candida albicans and pneumonia-related pathogens, Pseudomonas aeruginosa and Staphylococcus aureus, on in vitro biofilm formation and morphological change of 3 Candida species (C. albicans, C. glabrata, and C. tropicalis). Biofilm formation was evaluated by the crystal violet assay and colony-forming unit counts. Morphological characteristics of biofilms were evaluated by scanning electron microscopy and fluorescence microscopy. Addition of DNA at a low concentration (Candida species. In contrast, the addition of DNA at a high concentration (10 μg ml(-1)) decreased the biofilm mass. Interestingly, the formation of hyphae in a dense network of yeast cells was observed in C. albicans biofilms exposed to a low concentration of DNA (Candida biofilm formation and suggested that eDNA may induce the morphological transition from yeast to hyphal growth form during C. albicans biofilm development. A novel therapy targeting eDNA may be applicable for Candida infection to decrease biofilm formation and hyphal formation. © 2014 The Society for Applied Microbiology.

  3. Penicillenols from a deep-sea fungus Aspergillus restrictus inhibit Candida albicans biofilm formation and hyphal growth.

    Science.gov (United States)

    Wang, Jie; Yao, Qi-Feng; Amin, Muhammad; Nong, Xu-Hua; Zhang, Xiao-Yong; Qi, Shu-Hua

    2017-06-01

    Penicillenols (A1, A2, B1, B2, C1 and C2) were isolated from Aspergillus restrictus DFFSCS006, and could differentially inhibit biofilm formation and eradicate pre-developed biofilms of Candida albicans. Their structure-bioactivity relationships suggested that the saturation of hydrocarbon chain at C-8, R-configuration of C-5 and trans-configuration of the double bond between C-5 and C-6 of pyrrolidine-2,4-dione unit were important for their anti-biofilm activities. Penicillenols A2 and B1 slowed the hyphal growth and suppressed the transcripts of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4. Moreover, penicillenols A2 and B1 were found to act synergistically with amphotericin B against C. albicans biofilm formation.

  4. Alginate oligosaccharides modify hyphal infiltration of Candida albicans in an in vitro model of invasive human candidosis.

    Science.gov (United States)

    Pritchard, M F; Jack, A A; Powell, L C; Sadh, H; Rye, P D; Hill, K E; Thomas, D W

    2017-09-01

    A novel alginate oligomer (OligoG CF-5/20) has been shown to potentiate antifungal therapy against a range of fungal pathogens. The current study assessed the effect of this oligomer on in vitro virulence factor expression and epithelial invasion by Candida species. Plate substrate assays and epithelial models were used to assess Candida albicans (CCUG 39343 and ATCC 90028) invasion, in conjunction with confocal laser scanning microscopy and histochemistry. Expression of candidal virulence factors was determined biochemically and by quantitative PCR (qPCR). Changes in surface charge of C. albicans following OligoG treatment were analysed using electrophoretic light scattering. OligoG induced marked alterations in hyphal formation in the substrate assays and reduced invasion in the epithelial model (P albicans was evident following OligoG treatment (P  0·05), qPCR demonstrated a reduction in phospholipase B (PLB2) and SAPs (SAP4 and SAP6) expression. OligoG CF-5/20 reduced in vitro virulence factor expression and invasion by C. albicans. These results, and the previously described potentiation of antifungal activity, define a potential therapeutic opportunity in the treatment of invasive candidal infections. © 2017 The Society for Applied Microbiology.

  5. A circadian rhythm regulating hyphal melanization in Cercospora kikuchii.

    Science.gov (United States)

    Bluhm, Burton H; Burnham, A Michele; Dunkle, Larry D

    2010-01-01

    Many metabolic and developmental processes in fungi are controlled by biological rhythms. Circadian rhythms approximate a daily (24 h) cycle and have been thoroughly studied in the model fungus, Neurospora crassa. However relatively few examples of true circadian rhythms have been documented among other filamentous fungi. In this study we describe a circadian rhythm underlying hyphal melanization in Cercospora kikuchii, an important pathogen of soybean. After growth in light or light : dark cycles, colonies transferred to darkness produced zonate bands of melanized hyphae interspersed with bands of hyaline hyphae. Rhythmic production of bands was remarkably persistent in the absence of external cues, lasting at least 7 d after transfer to darkness, and was compensated over a range of temperatures. As in N. crassa, blue light but not red light was sufficient to entrain the circadian rhythm in C. kikuchii, and a putative ortholog of white collar-1, one of the genes required for light responses in N. crassa, was identified in C. kikuchii. Circadian regulation of melanization is conserved in other members of the genus: Similar rhythms were identified in another field isolate of C. kikuchii as well as field isolates of C. beticola and C. sorghi, but not in wild-type strains of C. zeae-maydis or C. zeina. This report represents the first documented circadian rhythm among Dothideomycete fungi and provides a new opportunity to dissect the molecular basis of circadian rhythms among filamentous fungi.

  6. Catalase gene disruptant of the human pathogenic yeast Candida albicans is defective in hyphal growth, and a catalase-specific inhibitor can suppress hyphal growth of wild-type cells.

    Science.gov (United States)

    Nakagawa, Yoshiyuki

    2008-01-01

    Although the catalase gene (CAT1) disruptant of the human pathogenic yeast Candida albicans was viable under ordinary growth conditions, we previously found that it could not grow on YPD (yeast extract/peptone/dextrose) containing SDS or at higher growth temperatures. To investigate the pleiotrophic nature of the disruptant, we examined the effect of the catalase inhibitor 3-AT on the growth of wild-type strains. Surprisingly, the addition of 3-AT and SDS caused the wild-type cells to be non-viable on YPD plates. We found an additional phenotype of the catalase gene disruptant: it did not produce normal hyphae on Spider medium. Hyphal growth was observed in a CAP1 (Candida AP-1-like protein gene) disruptant, a HOG1 (high-osmolarity glycerol signaling pathway gene) disruptant, and the double CAP1/HOG1 disruptant, suggesting that the defect in hyphal formation by the catalase disruptant was independent of these genes. Addition of 3-AT and SDS to hyphae-inducing media suppressed growth of normal hyphae in the wild-type strain. The potential necessity for catalase action upon exposure to hyphae-inducing conditions was confirmed by the immediate elevation of the catalase gene message. In spite of the requirement for catalase during hyphal growth, the catalase gene disruptant was capable of forming germ tubes in medium containing serum.

  7. [Demonstration of β-1,2 mannan structures expressed on the cell wall of Candida albicans yeast form but not on the hyphal form by using monoclonal antibodies].

    Science.gov (United States)

    Aydın, Cevahir; Ataoğlu, Haluk

    2015-01-01

    Candida albicans is a polymorphic fungus that may be observed as both commensal and opportunistic pathogen in humans. As one of the major components of Candida cell wall structure, mannan plays an important role in the fungus-host cell interaction and in virulence. The ability to switch from yeast to hypha form of microorganism is crutial in the development of C.albicans infections. Hyphal form has different antigenic properties compared to yeast form and structural changes occur in the yeast cell wall during transition from yeast to hypha form. Although there are several factors associated with this transition process, sufficient information is not available. The aim of this study was to investigate the change of configuration in mannan structure found in C.albicans cell wall by using monoclonal antibodies. C.albicans (NIHA 207) serotype A strains were used as test strains throughout the study, together with Salmonella choleraesuis 211 and Salmonella infantis as controls with similar cell wall structures to that of C.albicans. Cultures were maintained on YPD-agar medium by incubating at 28°C for yeast forms, and on YPD-broth medium in a shaking incubator at 37°C for 3-4 hours for the growth of hyphal forms. Cells were harvested in the exponential phase, and after being washed, the mannan content from C.albicans were extracted from pellet by heating in 20 mM sodium citrate buffer for 90 minutes at 125°C. Hybridoma technique was used for the production of monoclonal antibodies. After immunizing the Balb/C mice with antigen, the splenocytes were harvested and fusion was performed between spleen cells and F0 myeloma cells. The clones grown in HAT medium were screened for the presence of antibody producing hybrid cells by ELISA method. The antibody isotypes were determined by using a commercial kit (Pierce Biotechnology, ABD). The culture supernatants which contained monoclonal antibodies were collected and purified according to the ammonium sulphate method

  8. Candida albicans AGE3, the ortholog of the S. cerevisiae ARF-GAP-encoding gene GCS1, is required for hyphal growth and drug resistance.

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    Thomas Lettner

    Full Text Available BACKGROUND: Hyphal growth and multidrug resistance of C. albicans are important features for virulence and antifungal therapy of this pathogenic fungus. METHODOLOGY/PRINCIPAL FINDINGS: Here we show by phenotypic complementation analysis that the C. albicans gene AGE3 is the functional ortholog of the yeast ARF-GAP-encoding gene GCS1. The finding that the gene is required for efficient endocytosis points to an important functional role of Age3p in endosomal compartments. Most C. albicans age3Delta mutant cells which grew as cell clusters under yeast growth conditions showed defects in filamentation under different hyphal growth conditions and were almost completely disabled for invasive filamentous growth. Under hyphal growth conditions only a fraction of age3Delta cells shows a wild-type-like polarization pattern of the actin cytoskeleton and lipid rafts. Moreover, age3Delta cells were highly susceptible to several unrelated toxic compounds including antifungal azole drugs. Irrespective of the AGE3 genotype, C-terminal fusions of GFP to the drug efflux pumps Cdr1p and Mdr1p were predominantly localized in the plasma membrane. Moreover, the plasma membranes of wild-type and age3Delta mutant cells contained similar amounts of Cdr1p, Cdr2p and Mdr1p. CONCLUSIONS/SIGNIFICANCE: The results indicate that the defect in sustaining filament elongation is probably caused by the failure of age3Delta cells to polarize the actin cytoskeleton and possibly of inefficient endocytosis. The high susceptibility of age3Delta cells to azoles is not caused by inefficient transport of efflux pumps to the cell membrane. A possible role of a vacuolar defect of age3Delta cells in drug susceptibility is proposed and discussed. In conclusion, our study shows that the ARF-GAP Age3p is required for hyphal growth which is an important virulence factor of C. albicans and essential for detoxification of azole drugs which are routinely used for antifungal therapy. Thus, it

  9. Regulation of vectorial supply of vesicles to the hyphal tip determines thigmotropism in Neurospora crassa.

    Science.gov (United States)

    Stephenson, Karen S; Gow, Neil A R; Davidson, Fordyce A; Gadd, Geoffrey M

    2014-03-01

    Thigmotropism is the ability of an organism to respond to a topographical stimulus by altering its axis of growth. The thigmotropic response of the model fungus Neurospora crassa was quantified using microfabricated glass slides with ridges of defined height. We show that the polarity machinery at the hyphal tip plays a role in the thigmotropic response of N. crassa. Deletion of N. crassa genes encoding the formin, BNI-1, and the Rho-GTPase, CDC-42, an activator of BNI-1 in yeast, CDC-24, its guanine nucleotide exchange factor (GEF), and BEM-1, a scaffold protein in the same pathway, were all shown to significantly decrease the thigmotropic response. In contrast, deletion of genes encoding the cell end-marker protein, TEA-1, and KIP-1, the kinesin responsible for the localisation of TEA-1, significantly increased the thigmotropic response. These results suggest a mechanism of thigmotropism involving vesicle delivery to the hyphal tip via the actin cytoskeleton and microtubules. Neurospora crassa thigmotropic response differed subtly from that of Candida albicans where the stretch-activated calcium channel, Mid1, has been linked with thigmotropic behaviour. The MID-1 deficient mutant of N. crassa (Δmid-1) and the effects of calcium depletion were examined here but no change in the thigmotropic response was observed. However, SPRAY, a putative calcium channel protein, was shown to be required for N. crassa thigmotropism. We propose that the thigmotropic response is a result of changes in the polarity machinery at the hyphal tip which are thought to be downstream effects of calcium signalling pathways triggered by mechanical stress at the tip. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  10. Depletion of the mitotic kinase Cdc5p in Candida albicans results in the formation of elongated buds that switch to the hyphal fate over time in a Ume6p and Hgc1p-dependent manner.

    Science.gov (United States)

    Glory, Amandeep; van Oostende, Chloë Triplet; Geitmann, Anja; Bachewich, Catherine

    2017-10-01

    The fungal pathogen Candida albicans differentiates between yeast, hyphae and pseudohyphae in order to enhance survival in the human host. Environmental cues induce hyphal development and expression of hyphal-specific genes. Filaments also result from yeast cell cycle arrest, but the nature of these cells and their mechanisms of formation are less clear. We previously demonstrated that depletion of the mitotic polo-like kinase Cdc5p resulted in the production of filaments under yeast growth conditions that were distinct from hyphae with respect to several criteria, yet expressed hyphal-specific genes at later stages of development. In order to clarify the identity of these growth forms and their relationship to true hyphae, we conducted time course-based investigations of aspects of the polar growth machinery, which can distinguish cell types. During later stages of Cdc5p depletion, the myosin light chain Mlc1p demonstrated a Spitzenkörper-like localization in the tips of some filaments, and the Cdc42p GAP Rga2p became hyper-phosphorylated, as in true hyphae. Hyphal-specific genes HWP1, UME6 and HGC1 were strongly expressed at approximately the same time. HWP1 expression was dependent on Ume6p, and absence of Ume6p or Hgc1p influenced late-stage filament morphology and integrity. Finally, polarized growth and UME6 expression in Cdc5p-depleted cells were independent of the transcription factor Hms1p. Thus, depleting Cdc5p generates elongated buds that switch to a hyphal fate over time through a mechanism that involves UME6 and HGC1 induction, possibly in response to maintenance of polarized growth. The results expand on the multiple strategies with which C. albicans can modulate growth mode and expression of virulence determinants. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1 in Non-Candida albicans Candida (NCAC Species

    Directory of Open Access Journals (Sweden)

    Wan Himratul Aznita Wan Harun

    2013-01-01

    Full Text Available The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1×106 cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C. Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product.

  12. Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum.

    Science.gov (United States)

    Corral-Ramos, Cristina; Roca, M Gabriela; Di Pietro, Antonio; Roncero, M Isabel G; Ruiz-Roldán, Carmen

    2015-01-01

    In the fungal pathogen Fusarium oxysporum, vegetative hyphal fusion triggers nuclear mitotic division in the invading hypha followed by migration of a nucleus into the receptor hypha and degradation of the resident nucleus. Here we examined the role of autophagy in fusion-induced nuclear degradation. A search of the F. oxysporum genome database for autophagy pathway components identified putative orthologs of 16 core autophagy-related (ATG) genes in yeast, including the ubiquitin-like protein Atg8, which is required for the formation of autophagosomal membranes. F. oxysporum Foatg8Δ mutants were generated in a strain harboring H1-cherry fluorescent protein (ChFP)-labeled nuclei to facilitate analysis of nuclear dynamics. The Foatg8Δ mutants did not show MDC-positive staining in contrast to the wild type and the FoATG8-complemented (cFoATG8) strain, suggesting that FoAtg8 is required for autophagy in F. oxysporum. The Foatg8Δ strains displayed reduced rates of hyphal growth, conidiation, and fusion, and were significantly attenuated in virulence on tomato plants and in the nonvertebrate animal host Galleria mellonella. In contrast to wild-type hyphae, which are almost exclusively composed of uninucleated hyphal compartments, the hyphae of the Foatg8Δ mutants contained a significant fraction of hyphal compartments with 2 or more nuclei. The increase in the number of nuclei per hyphal compartment was particularly evident after hyphal fusion events. Time-lapse microscopy analyses revealed abnormal mitotic patterns during vegetative growth in the Foatg8Δ mutants. Our results suggest that autophagy mediates nuclear degradation after hyphal fusion and has a general function in the control of nuclear distribution in F. oxysporum.

  13. Quercetin Sensitizes Fluconazole-Resistant Candida albicans To Induce Apoptotic Cell Death by Modulating Quorum Sensing

    OpenAIRE

    Singh, B. N.; Upreti, D. K.; Singh, B. R.; Pandey, G.; Verma, S.; Roy, S.; Naqvi, A. H.; Rawat, A. K. S.

    2015-01-01

    Quorum sensing (QS) regulates group behaviors of Candida albicans such as biofilm, hyphal growth, and virulence factors. The sesquiterpene alcohol farnesol, a QS molecule produced by C. albicans, is known to regulate the expression of virulence weapons of this fungus. Fluconazole (FCZ) is a broad-spectrum antifungal drug that is used for the treatment of C. albicans infections. While FCZ can be cytotoxic at high concentrations, our results show that at much lower concentrations, quercetin (QC...

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

    Science.gov (United States)

    Van Hauwenhuyse, Frédérique; Fiori, Alessandro

    2014-01-01

    Morphogenetic transitions of the opportunistic fungal pathogen Candida albicans are 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 in C. 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 in C. albicans and suggest an association between ergosterol content and elongated growth upon Hsp90 compromise. PMID:25084864

  15. Hyphal Orientation of Candida albicans Is Regulated by a Calcium-Dependent Mechanism

    OpenAIRE

    Brand, Alexandra; Shanks, Scott; Duncan, Vanessa M.S.; Yang, Meng; Mackenzie, Kevin; Gow, Neil A.R.

    2007-01-01

    Summary Eukaryotic cells from fungal hyphae to neurites that grow by polarized extension must coordinate cell growth and cell orientation to enable them to exhibit growth tropisms and to respond to relevant environmental cues. Such cells generally maintain a tip-high Ca2+ cytoplasmic gradient, which is correlated with their ability to exhibit polarized tip growth and to respond to growth-directing extracellular signals [1?5]. In yeast and other fungi, the polarisome, exocyst, Arp2/3, and Spit...

  16. Cross regulation between Candida albicans catalytic and regulatory subunits of protein kinase A.

    Science.gov (United States)

    Giacometti, Romina; Kronberg, Florencia; Biondi, Ricardo M; Hernández, Alejandra I; Passeron, Susana

    2012-01-01

    In the pathogen Candida albicans protein kinase A (PKA) catalytic subunit is encoded by two genes TPK1 and TPK2 and the regulatory subunit by one gene, BCY1. PKA mediates several cellular processes such as cell cycle regulation and the yeast to hyphae transition, a key factor for C. albicans virulence. The catalytic isoforms Tpk1p and Tpk2p share redundant functions in vegetative growth and hyphal development, though they differentially regulate glycogen metabolism, the stress response pathway and pseudohyphal formation. In Saccharomyces cerevisiae it was earlier reported that BCY1 overexpression not only increased the amount of TPK3 mRNA but also its catalytic activity. In C. albicans a significant decrease in Bcy1p expression levels was already observed in tpk2Δ null strains. In this work we showed that the upregulation in Bcy1p expression was observed in a set of strains having a TPK1 or TPK2 allele reintegrated in its own locus, as well as in strains expressing the TPKs under the control of the constitutive ACT1 promoter. To confirm the cross regulation event between Bcy1p and Tpkp expression we generated a mutant strain with the lowest PKA activity carrying one TPK1 and a unique BCY1 allele with the aim to obtain two derived strains in which BCY1 or TPK1 were placed under their own promoters inserted in the RPS10 neutral locus. We found that placing one copy of BCY1 upregulated the levels of Tpk1p and its catalytic activity; while TPK1 insertion led to an increase in BCY1 mRNA, Bcy1p and in a high cAMP binding activity. Our results suggest that C. albicans cells were able to compensate for the increased levels of either Tpk1p or Tpk2p subunits with a corresponding elevation of Bcy1 protein levels and vice versa, implying a tightly regulated mechanism to balance holoenzyme formation. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. The MARVEL domain protein Nce102 regulates actin organization and invasive growth of Candida albicans.

    Science.gov (United States)

    Douglas, Lois M; Wang, Hong X; Konopka, James B

    2013-11-26

    Invasive growth of the fungal pathogen Candida albicans into tissues promotes disseminated infections in humans. The plasma membrane is essential for pathogenesis because this important barrier mediates morphogenesis and invasive growth, as well as secretion of virulence factors, cell wall synthesis, nutrient import, and other processes. Previous studies showed that the Sur7 tetraspan protein that localizes to MCC (membrane compartment occupied by Can1)/eisosome subdomains of the plasma membrane regulates a broad range of key functions, including cell wall synthesis, morphogenesis, and resistance to copper. Therefore, a distinct tetraspan protein found in MCC/eisosomes, Nce102, was investigated. Nce102 belongs to the MARVEL domain protein family, which is implicated in regulating membrane structure and function. Deletion of NCE102 did not cause the broad defects seen in sur7Δ cells. Instead, the nce102Δ mutant displayed a unique phenotype in that it was defective in forming hyphae and invading low concentrations of agar but could invade well in higher agar concentrations. This phenotype was likely due to a defect in actin organization that was observed by phalloidin staining. In support of this, the invasive growth defect of a bni1Δ mutant that mislocalizes actin due to lack of the Bni1 formin was also reversed at high agar concentrations. This suggests that a denser matrix provides a signal that compensates for the actin defects. The nce102Δ mutant displayed decreased virulence and formed abnormal hyphae in mice. These studies identify novel ways that Nce102 and the physical environment surrounding C. albicans regulate morphogenesis and pathogenesis. The plasma membrane promotes virulence of the human fungal pathogen Candida albicans by acting as a protective barrier around the cell and mediating dynamic activities, such as morphogenesis, cell wall synthesis, secretion of virulence factors, and nutrient uptake. To better understand how the plasma membrane

  18. Alcohols inhibit translation to regulate morphogenesis in C. albicans.

    Science.gov (United States)

    Egbe, Nkechi E; Paget, Caroline M; Wang, Hui; Ashe, Mark P

    2015-04-01

    Many molecules are secreted into the growth media by microorganisms to modulate the metabolic and physiological processes of the organism. For instance, alcohols like butanol, ethanol and isoamyl alcohol are produced by the human pathogenic fungus, Candida albicans and induce morphological differentiation. Here we show that these same alcohols cause a rapid inhibition of protein synthesis. More specifically, the alcohols target translation initiation, a complex stage of the gene expression process. Using molecular techniques, we have identified the likely translational target of these alcohols in C. albicans as the eukaryotic translation initiation factor 2B (eIF2B). eIF2B is the guanine nucleotide exchange factor for eIF2, which supports the exchange reaction where eIF2.GDP is converted to eIF2.GTP. Even minimal regulation at this step will lead to alterations in the levels of specific proteins that may allow the exigencies of the fungus to be realised. Indeed, similar to the effects of alcohols, a minimal inhibition of protein synthesis with cycloheximide also causes an induction of filamentous growth. These results suggest a molecular basis for the effect of various alcohols on morphological differentiation in C. albicans. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Candida albicans Hyphae: From Growth Initiation to Invasion

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    Jigar V. Desai

    2018-01-01

    Full Text Available Candida albicans is a commensal resident of the human gastrointestinal and genital tracts. Under conditions such as dysbiosis, host immune perturbances, or the presence of catheters/implanted medical devices, the fungus may cause debilitating mucosal or fatal systemic infections. The ability of C. albicans to grow as long filamentous hyphae is critical for its pathogenic potential as it allows the fungus to invade the underlying substratum. In this brief review, I will outline the current understanding regarding the mechanistic regulation of hyphal growth and invasion in C. albicans.

  20. Candida albicans Lacking the Gene Encoding the Regulatory Subunit of Protein Kinase A Displays a Defect in Hyphal Formation and an Altered Localization of the Catalytic Subunit

    Science.gov (United States)

    Cassola, Alejandro; Parrot, Marc; Silberstein, Susana; Magee, Beatrice B.; Passeron, Susana; Giasson, Luc; Cantore, María L.

    2004-01-01

    The fungal pathogen Candida albicans switches from a yeast-like to a filamentous mode of growth in response to a variety of environmental conditions. We examined the morphogenetic behavior of C. albicans yeast cells lacking the BCY1 gene, which encodes the regulatory subunit of protein kinase A. We cloned the BCY1 gene and generated a bcy1 tpk2 double mutant strain because a homozygous bcy1 mutant in a wild-type genetic background could not be obtained. In the bcy1 tpk2 mutant, protein kinase A activity (due to the presence of the TPK1 gene) was cyclic AMP independent, indicating that the cells harbored an unregulated phosphotransferase activity. This mutant has constitutive protein kinase A activity and displayed a defective germinative phenotype in N-acetylglucosamine and in serum-containing medium. The subcellular localization of a Tpk1-green fluorescent protein (GFP) fusion protein was examined in wild-type, tpk2 null, and bcy1 tpk2 double mutant strains. The fusion protein was observed to be predominantly nuclear in wild-type and tpk2 strains. This was not the case in the bcy1 tpk2 double mutant, where it appeared dispersed throughout the cell. Coimmunoprecipitation of Bcy1p with the Tpk1-GFP fusion protein demonstrated the interaction of these proteins inside the cell. These results suggest that one of the roles of Bcy1p is to tether the protein kinase A catalytic subunit to the nucleus. PMID:14871949

  1. Modulation of Candida albicans virulence by bacterial biofilms on titanium surfaces.

    Science.gov (United States)

    Cavalcanti, Yuri Wanderley; Wilson, Melanie; Lewis, Michael; Del-Bel-Cury, Altair Antoninha; da Silva, Wander José; Williams, David W

    2016-01-01

    Whilst Candida albicans occurs in peri-implant biofilms, its role in peri-implantitis remains unclear. This study therefore examined the virulence of C. albicans in mixed-species biofilms on titanium surfaces. Biofilms of C. albicans (Ca), C. albicans with streptococci (Streptococcus sanguinis, S. mutans) (Ca-Ss-Sm) and those incorporating Porphyromonas gingivalis (Ca-Pg and Ca-Ss-Sm-Pg) were developed. Expression of C. albicans genes associated with adhesion (ALS1, ALS3, HWP1) and hydrolytic enzymes (SAP2, SAP4, SAP6, PLD1) was measured and hyphal production by C. albicans quantified. Compared with Ca biofilms, significant (pbiofilms containing streptococci (Ca-Ss-Sm). In Ca-Pg biofilms, down-regulation of HWP1 and SAP4 expression, with reduced hyphal production occurred. Ca-Ss-Sm-Pg biofilms had increased hyphal proportions and up-regulation of ALS3, SAP2 and SAP6. In conclusion, C. albicans expressed virulence factors in biofilms that could contribute to peri-implantitis, but this was dependent on associated bacterial species.

  2. Phospholipid biosynthesis in Candida albicans: Regulation by the precursors inositol and choline

    International Nuclear Information System (INIS)

    Klig, L.S.; Friedli, L.; Schmid, E.

    1990-01-01

    Phospholipid metabolism in the pathogenic fungus Candida albicans was examined. The phospholipid biosynthetic pathways of C. albicans were elucidated and were shown to be similar to those of Saccharomyces cerevisiae. However, marked differences were seen between these two fungi in the regulation of the pathways in response to exogenously provided precursors inositol and choline. In S. cerevisiae, the biosynthesis of phosphatidylcholine via methylation of phosphatidylethanolamine appears to be regulated in response to inositol and choline; provision of choline alone does not repress the activity of this pathway. The same pathway in C. albicans responds to the exogenous provision of choline. Possible explanations for the observed differences in regulation are discussed

  3. Development and regulation of single- and multi-species Candida albicans biofilms

    Science.gov (United States)

    Lohse, Matthew B.; Gulati, Megha; Johnson, Alexander D.; Nobile, Clarissa J.

    2017-01-01

    Candida albicans is among the most prevalent fungal species of the human microbiota and asymptomatically colonizes healthy individuals. However, it is also an opportunistic pathogen that can cause severe, and often fatal, bloodstream infections. The medical impact of C. albicans typically depends on its ability to form biofilms, which are closely packed communities of cells that attach to surfaces, such as tissues and implanted medical devices. In this Review, we provide an overview of the processes involved in the formation of C. albicans biofilms and discuss the core transcriptional network that regulates biofilm development. We also consider some of the advantages that biofilms provide to C. albicans in comparison with planktonic growth and explore polymicrobial biofilms that are formed by C. albicans and certain bacterial species. PMID:29062072

  4. Germ tube growth of Candida albicans.

    Science.gov (United States)

    Gow, N A

    1997-12-01

    The clinical pathogen Candida albicans is a budding yeast that is capable of forming a range of polarized and expanded cell shapes from pseudohyphae to true nonconstricted hyphae. Filamentous forms consist of contiguous uninucleated compartments that are partitioned by septa. It has long been held that the so-called "dimorphic transition" from a budding to a filamentous form may aid the fungus to penetrate epithelia and may therefore be a virulence factor. This review summarized new information regarding the physiology and ecology of hyphal growth in C. albicans. New evidence has demonstrated that hyphae of C. albicans have a sense of touch so that they grow along grooves and through pores (thigmotropism). This may aid infiltration of epithelial surfaces during tissue invasion. Hyphae are also aerotropic and can form helices when contacting solid surfaces. Growing evidence supports the view that hyphal growth is a response to nutrient deprivation, especially low nitrogen and that filamentous growth enables the fungus to forage for nutrients more effectively. Further insights into the growth of C. albicans have come from the analysis of genes and mutations of Saccharomyces which have begun to reveal the molecular mechanisms underlying the mechanisms of bud site selection, cell polarity and signal transduction pathways that lead to pseudohyphal development in this and other organisms. For example, it is now clear that a MAP-kinase cascade, homologous to the mating pathway in Saccharomyces, regulates filamentous growth in both fungi. However, this must be only one of several overlapping or separate signal transduction pathways for hyphal development because filamentous growth still occurs in mutants of Candida and Saccharomyces which are blocked in this pathway. Cell cycle analyses have shown that hyphal phase cell cycle of Candida is distinct from that in budding and pseudohyphal formation and so pseudohyphal growth of Saccharomyces is not a true model of germ tube

  5. The cAMP-PKA Signaling Pathway Regulates Pathogenicity, Hyphal Growth, Appressorial Formation, Conidiation, and Stress Tolerance in Colletotrichum higginsianum.

    Science.gov (United States)

    Zhu, Wenjun; Zhou, Man; Xiong, Zeyang; Peng, Fang; Wei, Wei

    2017-01-01

    Colletotrichum higginsianum is an economically important pathogen that causes anthracnose disease in a wide range of cruciferous crops. Understanding the mechanisms of the cruciferous plant- C. higginsianum interactions will be important in facilitating efficient control of anthracnose diseases. The cAMP-PKA signaling pathway plays important roles in diverse physiological processes of multiple pathogens. C. higginsianum contains two genes, ChPKA1 and ChPKA2 , that encode the catalytic subunits of cyclic AMP (cAMP)-dependent protein kinase A (PKA). To analyze the role of cAMP signaling pathway in pathogenicity and development in C. higginsianum , we characterized ChPKA1 and ChPKA2 genes, and adenylate cyclase ( ChAC ) gene. The ChPKA1 and ChAC deletion mutants were unable to cause disease and significantly reduced in hyphal growth, tolerance to cell wall inhibitors, conidiation, and appressorial formation with abnormal germ tubes, but they had an increased tolerance to elevated temperatures and exogenous H 2 O 2 . In contrast, the ChPKA2 mutant had no detectable alteration of phenotypes, suggesting that ChPKA1 contributes mainly to PKA activities in C. higginsianum . Moreover, we failed to generate Δ ChPKA1ChPKA2 double mutant, indicating that deletion of both PKA catalytic subunits is lethal in C. higginsianum and the two catalytic subunits possibly have overlapping functions. These results indicated that ChPKA1 is the major PKA catalytic subunit in cAMP-PKA signaling pathway and plays significant roles in hyphal growth, pathogenicity, appressorial formation, conidiation, and stress tolerance in C. higginsianum .

  6. The cAMP-PKA Signaling Pathway Regulates Pathogenicity, Hyphal Growth, Appressorial Formation, Conidiation, and Stress Tolerance in Colletotrichum higginsianum

    Directory of Open Access Journals (Sweden)

    Wenjun Zhu

    2017-07-01

    Full Text Available Colletotrichum higginsianum is an economically important pathogen that causes anthracnose disease in a wide range of cruciferous crops. Understanding the mechanisms of the cruciferous plant–C. higginsianum interactions will be important in facilitating efficient control of anthracnose diseases. The cAMP-PKA signaling pathway plays important roles in diverse physiological processes of multiple pathogens. C. higginsianum contains two genes, ChPKA1 and ChPKA2, that encode the catalytic subunits of cyclic AMP (cAMP-dependent protein kinase A (PKA. To analyze the role of cAMP signaling pathway in pathogenicity and development in C. higginsianum, we characterized ChPKA1 and ChPKA2 genes, and adenylate cyclase (ChAC gene. The ChPKA1 and ChAC deletion mutants were unable to cause disease and significantly reduced in hyphal growth, tolerance to cell wall inhibitors, conidiation, and appressorial formation with abnormal germ tubes, but they had an increased tolerance to elevated temperatures and exogenous H2O2. In contrast, the ChPKA2 mutant had no detectable alteration of phenotypes, suggesting that ChPKA1 contributes mainly to PKA activities in C. higginsianum. Moreover, we failed to generate ΔChPKA1ChPKA2 double mutant, indicating that deletion of both PKA catalytic subunits is lethal in C. higginsianum and the two catalytic subunits possibly have overlapping functions. These results indicated that ChPKA1 is the major PKA catalytic subunit in cAMP-PKA signaling pathway and plays significant roles in hyphal growth, pathogenicity, appressorial formation, conidiation, and stress tolerance in C. higginsianum.

  7. The Role of AIRE in the Immunity Against Candida Albicans in a Model of Human Macrophages

    Directory of Open Access Journals (Sweden)

    Jose Antonio Tavares de Albuquerque

    2018-03-01

    Full Text Available Autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED is a primary immunodeficiency caused by mutations in the autoimmune regulator gene (AIRE. Patients with AIRE mutations are susceptible to Candida albicans infection and present with autoimmune disorders. We previously demonstrated that cytoplasmic AIRE regulates the Syk-dependent Dectin-1 pathway. In this study, we further evaluated direct contact with fungal elements, synapse formation, and the response of macrophage-like THP-1 cells to C. albicans hyphae to determine the role of AIRE upon Dectin receptors function and signaling. We examined the fungal synapse (FS formation in wild-type and AIRE-knockdown THP-1 cells differentiated to macrophages, as well as monocyte-derived macrophages from APECED patients. We evaluated Dectin-2 receptor signaling, phagocytosis, and cytokine secretion upon hyphal stimulation. AIRE co-localized with Dectin-2 and Syk at the FS upon hyphal stimulation of macrophage-like THP-1 cells. AIRE-knockdown macrophage-like THP-1 cells exhibited less Dectin-1 and Dectin-2 receptors accumulation, decreased signaling pathway activity at the FS, lower C. albicans phagocytosis, and less lysosome formation. Furthermore, IL-1β, IL-6, or TNF-α secretion by AIRE-knockdown macrophage-like THP-1 cells and AIRE-deficient patient macrophages was decreased compared to control cells. Our results suggest that AIRE modulates the FS formation and hyphal recognition and help to orchestrate an effective immune response against C. albicans.

  8. Retigeric acid B attenuates the virulence of Candida albicans via inhibiting adenylyl cyclase activity targeted by enhanced farnesol production.

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    Wenqiang Chang

    Full Text Available Candida albicans, the most prevalent fungal pathogen, undergoes yeast-to-hyphal switch which has long been identified as a key fungal virulence factor. We showed here that the lichen-derived small molecule retigeric acid B (RAB acted as an inhibitor that significantly inhibited the filamentation of C. albicans, leading to the prolonged survival of nematodes infected by C. albicans. Quantitative real-time PCR analysis and intracellular cAMP measurement revealed RAB regulated the Ras1-cAMP-Efg1 pathway by reducing cAMP level to inhibit the hyphae formation. Confocal microscopic observation showed RAB induced the expression of Dpp3, synthesizing more farnesol, which was confirmed by gas chromatography-mass spectroscopy detection. An adenylyl cyclase activity assay demonstrated RAB could repress the activity of Cdc35 through stimulating farnesol synthesis, thus causing a decrease in cAMP synthesis, leading to retarded yeast-to-hyphal transition. Moreover, reduced levels of intracellular cAMP resulted in the inhibition of downstream adhesins. Together, these findings indicate that RAB stimulates farnesol production that directly inhibits the Cdc35 activity, reducing the synthesis of cAMP and thereby causing the disruption of the morphologic transition and attenuating the virulence of C. albicans. Our work illustrates the underlying mechanism of RAB-dependent inhibition of the yeast-to-hyphal switch and provides a potential application in treating the infection of C. albicans.

  9. Hyphal structures in Hydnums

    NARCIS (Netherlands)

    Maas Geesteranus, R.A.

    1962-01-01

    In this paper descriptions are given of the hyphal structure in the hydnaceous genera Climacodon P. Karst., Creolophus P. Karst., Donkia Pilát, Hydnellum P. Karst., Mycoleptodonoides Nikol., Mycorrhaphium Maas G. (which is introduced as a new genus), Phellodon P. Karst., Sarcodon P. Karst., and

  10. Candida albicans Tpk1p and Tpk2p isoforms differentially regulate pseudohyphal development, biofilm structure, cell aggregation and adhesins expression.

    Science.gov (United States)

    Giacometti, Romina; Kronberg, Florencia; Biondi, Ricardo M; Passeron, Susana

    2011-04-01

    Candida albicans undergoes a reversible morphological transition from single yeast cells to pseudohyphal and hyphal filaments. In this organism, cAMP-dependent protein kinase (PKA), coded by two catalytic subunits (TPK1 and TPK2) and one regulatory subunit (BCY1), mediates basic cellular processes, such as the yeast-to-hypha transition and cell cycle regulation. It is known that both Tpk isoforms play positive roles in vegetative growth and filamentation, although distinct roles have been found in virulence, stress response and glycogen storage. However, little is known regarding the participation of Tpk1p and/or Tpk2p in pseudohyphal development. This point was addressed using several C. albicans PKA mutants having heterozygous or homozygous deletions of TPK1 and/or TPK2 in different BCY1 genetic backgrounds. We observed that under hypha-only inducing conditions, all BCY1 heterozygous strains shifted growth toward pseudohyphal morphology; however, the pseudohypha:hypha ratio was higher in strains devoid of TPK2. Under pseudohypha-only inducing conditions, strains lacking TPK2 were prone to develop short and branched pseudohyphae. In tpk2 Δ/tpk2 Δ strains, biofilm architecture was markedly less dense, composed of short pseudohyphae and blastospores with reduced adhesion ability to abiotic material, suggesting a significant defect in cell adherence. Immunolabelling assays showed a decreased expression of adhesins Als1p and Als3p only in the tpk2 Δ/tpk2 Δ strain. Complementation of this mutant with a wild-type copy of TPK2 restored all the altered functions: pseudohyphae elongation, biofilm composition, cell aggregation and adhesins expression. Our study suggests that the Tpk2p isoform may be part of a mechanism underlying not only polarized pseudohyphal morphogenesis but also cell adherence. Copyright © 2011 John Wiley & Sons, Ltd.

  11. A computational model for regulation of nanoscale glucan exposure in Candida albicans

    OpenAIRE

    Wester, Michael J.; Lin, Jia; Neumann, Aaron K.

    2017-01-01

    Candida albicans is a virulent human opportunistic pathogen. It evades innate immune surveillance by masking an immunogenic cell wall polysaccharide, β-glucan, from recognition by the immunoreceptor Dectin-1. Glucan unmasking by the antifungal drug caspofungin leads to changes in the nanostructure of glucan exposure accessible to Dectin-1. The physical mechanism that regulates glucan exposure is poorly understood, but it controls the nanobiology of fungal pathogen recognition. We created comp...

  12. Identification of infection- and defense-related genes via a dynamic host-pathogen interaction network using a Candida albicans-zebrafish infection model.

    Science.gov (United States)

    Kuo, Zong-Yu; Chuang, Yung-Jen; Chao, Chun-Cheih; Liu, Fu-Chen; Lan, Chung-Yu; Chen, Bor-Sen

    2013-01-01

    Candida albicans infections and candidiasis are difficult to treat and create very serious therapeutic challenges. In this study, based on interactive time profile microarray data of C. albicans and zebrafish during infection, the infection-related protein-protein interaction (PPI) networks of the two species and the intercellular PPI network between host and pathogen were simultaneously constructed by a dynamic interaction model, modeled as an integrated network consisting of intercellular invasion and cellular defense processes during infection. The signal transduction pathways in regulating morphogenesis and hyphal growth of C. albicans were further investigated based on significant interactions found in the intercellular PPI network. Two cellular networks were also developed corresponding to the different infection stages (adhesion and invasion), and then compared with each other to identify proteins from which we can gain more insight into the pathogenic role of hyphal development in the C. albicans infection process. Important defense-related proteins in zebrafish were predicted using the same approach. The hyphal growth PPI network, zebrafish PPI network and host-pathogen intercellular PPI network were combined to form an integrated infectious PPI network that helps us understand the systematic mechanisms underlying the pathogenicity of C. albicans and the immune response of the host, and may help improve medical therapies and facilitate the development of new antifungal drugs. Copyright © 2013 S. Karger AG, Basel.

  13. An Internal Polarity Landmark Is Important for Externally Induced Hyphal Behaviors in Candida albicans▿

    Science.gov (United States)

    Brand, Alexandra; Vacharaksa, Anjalee; Bendel, Catherine; Norton, Jennifer; Haynes, Paula; Henry-Stanley, Michelle; Wells, Carol; Ross, Karen; Gow, Neil A. R.; Gale, Cheryl A.

    2008-01-01

    Directional growth is a function of polarized cells such as neurites, pollen tubes, and fungal hyphae. Correct orientation of the extending cell tip depends on signaling pathways and effectors that mediate asymmetric responses to specific environmental cues. In the hyphal form of the eukaryotic fungal pathogen Candida albicans, these responses include thigmotropism and galvanotropism (hyphal turning in response to changes in substrate topography and imposed electrical fields, respectively) and penetration into semisolid substrates. During vegetative growth in C. albicans, as in the model yeast Saccharomyces cerevisiae, the Ras-like GTPase Rsr1 mediates internal cellular cues to position new buds in a prespecified pattern on the mother cell cortex. Here, we demonstrate that Rsr1 is also important for hyphal tip orientation in response to the external environmental cues that induce thigmotropic and galvanotropic growth. In addition, Rsr1 is involved in hyphal interactions with epithelial cells in vitro and its deletion diminishes the hyphal invasion of kidney tissue during systemic infection. Thus, Rsr1, an internal polarity landmark in yeast, is also involved in polarized growth responses to asymmetric environmental signals, a paradigm that is different from that described for the homologous protein in S. cerevisiae. Rsr1 may thereby contribute to the pathogenesis of C. albicans infections by influencing hyphal tip responses triggered by interaction with host tissues. PMID:18281602

  14. Anion Exchanger 2 Regulates Dectin-1-Dependent Phagocytosis and Killing of Candida albicans.

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    Katia Urso

    Full Text Available Anion exchanger 2 (Ae2; gene symbol, Slc4a2 is a plasma membrane Cl-/HCO3- exchanger expressed in the gastrointestinal tract, kidney and bone. We have previously shown that Ae2 is required for the function of osteoclasts, bone resorbing cells of the macrophage lineage, to maintain homeostatic cytoplasmic pH and electroneutrality during acid secretion. Macrophages require endosomal acidification for pathogen killing during the process known as phagocytosis. Chloride is thought to be the principal ion responsible for maintaining electroneutrality during organelle acidification, but whether Cl-/HCO3- exchangers such as Ae2 contribute to macrophage function is not known. In this study we investigated the role of Ae2 in primary macrophages during phagocytosis. We find that Ae2 is expressed in macrophages where it regulates intracellular pH and the binding of Zymosan, a fungal cell wall derivative. Surprisingly, the transcription and surface expression of Dectin-1, the major phagocytic receptor for Candida albicans (C. albicans and Zymosan, is reduced in the absence of Ae2. As a consequence, Zymosan-induced Tnfα expression is also impaired in Ae2-deficient macrophages. Similar to Ae2 deficiency, pharmacological alkalinization of lysosomal pH with bafilomycin A decreases both Dectin-1 mRNA and cell surface expression. Finally, Ae2-deficient macrophages demonstrate defective phagocytosis and killing of the human pathogenic fungus C. albicans. Our results strongly suggest that Ae2 is a critical factor in the innate response to C. albicans. This study represents an important contribution to a better understanding of how Dectin-1 expression and fungal clearance is regulated.

  15. Control of the C. albicans cell wall damage response by transcriptional regulator Cas5.

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    Vincent M Bruno

    2006-03-01

    Full Text Available The fungal cell wall is vital for growth, development, and interaction of cells with their environment. The response to cell wall damage is well understood from studies in the budding yeast Saccharomyces cerevisiae, where numerous cell wall integrity (CWI genes are activated by transcription factor ScRlm1. Prior evidence suggests the hypothesis that both response and regulation may be conserved in the major fungal pathogen Candida albicans. We have tested this hypothesis by using a new C. albicans genetic resource: we have screened mutants defective in putative transcription factor genes for sensitivity to the cell wall biosynthesis inhibitor caspofungin. We find that the zinc finger protein CaCas5, which lacks a unique ortholog in S. cerevisiae, governs expression of many CWI genes. CaRlm1 has a modest role in this response. The transcriptional coactivator CaAda2 is also required for expression of many CaCas5-dependent genes, as expected if CaCas5 recruits CaAda2 to activate target gene transcription. Many caspofungin-induced C. albicans genes specify endoplasmic reticulum and secretion functions. Such genes are not induced in S. cerevisiae, but promote its growth in caspofungin. We have used a new resource to identify a key C. albicans transcriptional regulator of CWI genes and antifungal sensitivity. Our gene expression findings indicate that both divergent and conserved response genes may have significant functional roles. Our strategy may be broadly useful for identification of pathogen-specific regulatory pathways and critical response genes.

  16. Functional importance of the DNA binding activity of Candida albicans Czf1p.

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    Ivana Petrovska

    Full Text Available The human opportunistic pathogen Candida albicans undergoes a reversible morphological transition between the yeast and hyphal states in response to a variety of signals. One such environmental trigger is growth within a semisolid matrix such as agar medium. This growth condition is of interest because it may mimic the growth of C. albicans in contact with host tissue during infection. During growth within a semisolid matrix, hyphal growth is positively regulated by the transcriptional regulator Czf1p and negatively by a second key transcriptional regulator, Efg1p. Genetic studies indicate that Czf1p, a member of the zinc-cluster family of transcriptional regulators, exerts its function by opposing the inhibitory influence of Efg1p on matrix-induced filamentous growth. We examined the importance of the two known activities of Czf1p, DNA-binding and interaction with Efg1p. We found that the two activities were separable by mutation allowing us to demonstrate that the DNA-binding activity of Czf1p was essential for its role as a positive regulator of morphogenesis. Surprisingly, however, interactions with Efg1p appeared to be largely dispensable. Our studies provide the first evidence of a key role for the DNA-binding activity of Czf1p in the morphological yeast-to-hyphal transition triggered by matrix-embedded growth.

  17. Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans

    OpenAIRE

    Manoharan, Ranjith Kumar; Lee, Jin-Hyung; Lee, Jintae

    2017-01-01

    Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO), which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry...

  18. Comparative genomics of the fungal pathogens Candida dubliniensis and Candida albicans.

    LENUS (Irish Health Repository)

    Jackson, Andrew P

    2009-12-01

    Candida dubliniensis is the closest known relative of Candida albicans, the most pathogenic yeast species in humans. However, despite both species sharing many phenotypic characteristics, including the ability to form true hyphae, C. dubliniensis is a significantly less virulent and less versatile pathogen. Therefore, to identify C. albicans-specific genes that may be responsible for an increased capacity to cause disease, we have sequenced the C. dubliniensis genome and compared it with the known C. albicans genome sequence. Although the two genome sequences are highly similar and synteny is conserved throughout, 168 species-specific genes are identified, including some encoding known hyphal-specific virulence factors, such as the aspartyl proteinases Sap4 and Sap5 and the proposed invasin Als3. Among the 115 pseudogenes confirmed in C. dubliniensis are orthologs of several filamentous growth regulator (FGR) genes that also have suspected roles in pathogenesis. However, the principal differences in genomic repertoire concern expansion of the TLO gene family of putative transcription factors and the IFA family of putative transmembrane proteins in C. albicans, which represent novel candidate virulence-associated factors. The results suggest that the recent evolutionary histories of C. albicans and C. dubliniensis are quite different. While gene families instrumental in pathogenesis have been elaborated in C. albicans, C. dubliniensis has lost genomic capacity and key pathogenic functions. This could explain why C. albicans is a more potent pathogen in humans than C. dubliniensis.

  19. Disruption of the transcriptional regulator Cas5 results in enhanced killing of Candida albicans by Fluconazole.

    Science.gov (United States)

    Vasicek, Erin M; Berkow, Elizabeth L; Bruno, Vincent M; Mitchell, Aaron P; Wiederhold, Nathan P; Barker, Katherine S; Rogers, P David

    2014-11-01

    Azole antifungal agents such as fluconazole exhibit fungistatic activity against Candida albicans. Strategies to enhance azole antifungal activity would be therapeutically appealing. In an effort to identify transcriptional pathways that influence the killing activity of fluconazole, we sought to identify transcription factors (TFs) involved in this process. From a collection of C. albicans strains disrupted for genes encoding TFs (O. R. Homann, J. Dea, S. M. Noble, and A. D. Johnson, PLoS Genet. 5:e1000783, 2009, http://dx.doi.org/10.1371/journal.pgen.1000783), four strains exhibited marked reductions in minimum fungicidal concentration (MFCs) in both RPMI and yeast extract-peptone-dextrose (YPD) media. One of these genes, UPC2, was previously characterized with regard to its role in azole susceptibility. Of mutants representing the three remaining TF genes of interest, one (CAS5) was unable to recover from fluconazole exposure at concentrations as low as 2 μg/ml after 72 h in YPD medium. This mutant also showed reduced susceptibility and a clear zone of inhibition by Etest, was unable to grow on solid medium containing 10 μg/ml fluconazole, and exhibited increased susceptibility by time-kill analysis. CAS5 disruption in highly azole-resistant clinical isolates exhibiting multiple resistance mechanisms did not alter susceptibility. However, CAS5 disruption in strains with specific resistance mutations resulted in moderate reductions in MICs and MFCs. Genome-wide transcriptional analysis was performed in the presence of fluconazole and was consistent with the suggested role of CAS5 in cell wall organization while also suggesting a role in iron transport and homeostasis. These findings suggest that Cas5 regulates a transcriptional network that influences the response of C. albicans to fluconazole. Further delineation of this transcriptional network may identify targets for potential cotherapeutic strategies to enhance the activity of the azole class of antifungals

  20. Antifungal effects of undecylenic acid on the biofilm formation of Candida albicans.

    Science.gov (United States)

    Shi, Dongmei; Zhao, Yaxin; Yan, Hongxia; Fu, Hongjun; Shen, Yongnian; Lu, Guixia; Mei, Huan; Qiu, Ying; Li, Dongmei; Liu, Weida

    2016-05-01

    Undecylenic acid can effectively control skin fungal infection, but the mechanism of its fungal inhibition is unclear. Hyphal growth of Candida albicans (C. albicans) and biofilm formation have been well recognized as important virulence factors for the initiation of skin infection and late development of disseminated infection. In this study, we seek to investigate antifungal mechanisms of undecylenic acid by evaluating the virulence factors of C. albicans during biofilm formation. We found that undecylenic acid inhibits biofilm formation of C. albicans effectively with optimal concentration above 3 mM. In the presence of this compound, the morphological transition from yeast to filamentous phase is abolished ultimately when the concentration of undecylenic acid is above 4 mM. Meanwhile, the cell surface is crumpled, and cells display an atrophic appearance under scanning electron microscopy even with low concentration of drug treatment. On the other hand, the drug treatment decreases the transcriptions of hydrolytic enzymes such as secreted aspartic protease, lipase, and phospholipase. Hyphal formation related genes, like HWP1, are significantly reduced in transcriptional level in drug-treated biofilm condition as well. The down-regulated profile of these genes leads to a poorly organized biofilm in undecylenic acid treated environment.

  1. A computational model for regulation of nanoscale glucan exposure in Candida albicans.

    Science.gov (United States)

    Wester, Michael J; Lin, Jia; Neumann, Aaron K

    2017-01-01

    Candida albicans is a virulent human opportunistic pathogen. It evades innate immune surveillance by masking an immunogenic cell wall polysaccharide, β-glucan, from recognition by the immunoreceptor Dectin-1. Glucan unmasking by the antifungal drug caspofungin leads to changes in the nanostructure of glucan exposure accessible to Dectin-1. The physical mechanism that regulates glucan exposure is poorly understood, but it controls the nanobiology of fungal pathogen recognition. We created computational models to simulate hypothetical physical processes of unmasking glucan in a biologically realistic distribution of cell wall glucan fibrils. We tested the predicted glucan exposure nanostructural features arising from these models against experimentally measured values. A completely spatially random unmasking process, reflective of random environmental damage to the cell wall, cannot account for experimental observations of glucan unmasking. However, the introduction of partially edge biased unmasking processes, consistent with an unmasking contribution from active, local remodeling at glucan exposure sites, produces markedly more accurate predictions of experimentally observed glucan nanoexposures in untreated and caspofungin-treated yeast. These findings suggest a model of glucan unmasking wherein cell wall remodeling processes in the local nanoscale neighborhood of glucan exposure sites are an important contributor to the physical process of drug-induced glucan unmasking in C. albicans.

  2. A computational model for regulation of nanoscale glucan exposure in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Michael J Wester

    Full Text Available Candida albicans is a virulent human opportunistic pathogen. It evades innate immune surveillance by masking an immunogenic cell wall polysaccharide, β-glucan, from recognition by the immunoreceptor Dectin-1. Glucan unmasking by the antifungal drug caspofungin leads to changes in the nanostructure of glucan exposure accessible to Dectin-1. The physical mechanism that regulates glucan exposure is poorly understood, but it controls the nanobiology of fungal pathogen recognition. We created computational models to simulate hypothetical physical processes of unmasking glucan in a biologically realistic distribution of cell wall glucan fibrils. We tested the predicted glucan exposure nanostructural features arising from these models against experimentally measured values. A completely spatially random unmasking process, reflective of random environmental damage to the cell wall, cannot account for experimental observations of glucan unmasking. However, the introduction of partially edge biased unmasking processes, consistent with an unmasking contribution from active, local remodeling at glucan exposure sites, produces markedly more accurate predictions of experimentally observed glucan nanoexposures in untreated and caspofungin-treated yeast. These findings suggest a model of glucan unmasking wherein cell wall remodeling processes in the local nanoscale neighborhood of glucan exposure sites are an important contributor to the physical process of drug-induced glucan unmasking in C. albicans.

  3. The inhibitory activity of linalool against the filamentous growth and biofilm formation in Candida albicans.

    Science.gov (United States)

    Hsu, Chih-Chieh; Lai, Wen-Lin; Chuang, Kuei-Chin; Lee, Meng-Hwan; Tsai, Ying-Chieh

    2013-07-01

    Candida spp. are part of the natural human microbiota, but they also represent important opportunistic human pathogens. Biofilm-associated Candida albicans infections are clinically relevant due to their high levels of resistance to traditional antifungal agents. In this study, we investigated the ability of linalool to inhibit the formation of C. albicans biofilms and reduce existing C. albicans biofilms. Linalool exhibited antifungal activity against C. albicans ATCC 14053, with a minimum inhibitory concentration (MIC) of 8 mM. Sub-MIC concentrations of linalool also inhibited the formation of germ tubes and biofilms in that strain. The defective architecture composition of C. albicans biofilms exposed to linalool was characterized by scanning electron microscopy. The expression levels of the adhesin genes HWP1 and ALS3 were downregulated by linalool, as assessed by real-time RT-PCR. The expression levels of CYR1 and CPH1, which encode components of the cAMP-PKA and MAPK hyphal formation regulatory pathways, respectively, were also suppressed by linalool, as was the gene encoding their upstream regulator, Ras1. The expression levels of long-term hyphae maintenance associated genes, including UME6, HGC1, and EED1, were all suppressed by linalool. These results indicate that linalool may have therapeutic potential in the treatment of candidiasis associated with medical devices because it interferes with the morphological switch and biofilm formation of C. albicans.

  4. Quercetin sensitizes fluconazole-resistant candida albicans to induce apoptotic cell death by modulating quorum sensing.

    Science.gov (United States)

    Singh, B N; Upreti, D K; Singh, B R; Pandey, G; Verma, S; Roy, S; Naqvi, A H; Rawat, A K S

    2015-04-01

    Quorum sensing (QS) regulates group behaviors of Candida albicans such as biofilm, hyphal growth, and virulence factors. The sesquiterpene alcohol farnesol, a QS molecule produced by C. albicans, is known to regulate the expression of virulence weapons of this fungus. Fluconazole (FCZ) is a broad-spectrum antifungal drug that is used for the treatment of C. albicans infections. While FCZ can be cytotoxic at high concentrations, our results show that at much lower concentrations, quercetin (QC), a dietary flavonoid isolated from an edible lichen (Usnea longissima), can be implemented as a sensitizing agent for FCZ-resistant C. albicans NBC099, enhancing the efficacy of FCZ. QC enhanced FCZ-mediated cell killing of NBC099 and also induced cell death. These experiments indicated that the combined application of both drugs was FCZ dose dependent rather than QC dose dependent. In addition, we found that QC strongly suppressed the production of virulence weapons-biofilm formation, hyphal development, phospholipase, proteinase, esterase, and hemolytic activity. Treatment with QC also increased FCZ-mediated cell death in NBC099 biofilms. Interestingly, we also found that QC enhances the anticandidal activity of FCZ by inducing apoptotic cell death. We have also established that this sensitization is reliant on the farnesol response generated by QC. Molecular docking studies also support this conclusion and suggest that QC can form hydrogen bonds with Gln969, Thr1105, Ser1108, Arg1109, Asn1110, and Gly1061 in the ATP binding pocket of adenylate cyclase. Thus, this QS-mediated combined sensitizer (QC)-anticandidal agent (FCZ) strategy may be a novel way to enhance the efficacy of FCZ-based therapy of C. albicans infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Candida albicans response regulator gene SSK1 regulates a subset of genes whose functions are associated with cell wall biosynthesis and adaptation to oxidative stress.

    Science.gov (United States)

    Chauhan, Neeraj; Inglis, Diane; Roman, Elvira; Pla, Jesus; Li, Dongmei; Calera, Jose A; Calderone, Richard

    2003-10-01

    Ssk1p of Candida albicans is a putative response regulator protein of the Hog1 two-component signal transduction system. In Saccharomyces cerevisiae, the phosphorylation state of Ssk1p determines whether genes that promote the adaptation of cells to osmotic stress are activated. We have previously shown that C. albicans SSK1 does not complement the ssk1 mutant of S. cerevisiae and that the ssk1 mutant of C. albicans is not sensitive to sorbitol. In this study, we show that the C. albicans ssk1 mutant is sensitive to several oxidants, including hydrogen peroxide, t-butyl hydroperoxide, menadione, and potassium superoxide when each is incorporated in yeast extract-peptone-dextrose (YPD) agar medium. We used DNA microarrays to identify genes whose regulation is affected by the ssk1 mutation. RNA from mutant cells (strain CSSK21) grown in YPD medium for 3 h at 30 degrees C was reverse transcribed and then compared with similarly prepared RNA from wild-type cells (CAF2). We observed seven genes from mutant cells that were consistently up regulated (three-fold or greater compared to CAF2). In S. cerevisiae, three (AHP1, HSP12, and PYC2) of the seven genes that were up regulated provide cells with an adaptation function in response to oxidative stress; another gene (GPH1) is regulated under stress conditions by Hog1p. Three other genes that are up regulated encode a cell surface protein (FLO1), a mannosyl transferase (MNN4-4), and a putative two-component histidine kinase (CHK1) that regulates cell wall biosynthesis in C. albicans. Of the down-regulated genes, ALS1 is a known cell adhesin in C. albicans. Verification of the microarray data was obtained by reverse transcription-PCR for HSP12, AHP1, CHK1, PYC2, GPH1, ALS1, MNN4-4, and FLO1. To further determine the function of Ssk1p in the Hog1p signal transduction pathway in C. albicans, we used Western blot analysis to measure phosphorylation of Hog1p in the ssk1 mutant of C. albicans when grown under either osmotic or

  6. Regulation of Candida albicans Interaction with Macrophages through the Activation of HOG Pathway by Genistein

    Directory of Open Access Journals (Sweden)

    Shuna Cui

    2016-01-01

    Full Text Available The severity of infections caused by Candida albicans, the most common opportunistic human fungal pathogen, needs rapid and effective antifungal treatments. One of the effective ways is to control the virulence factors of the pathogen. Therefore, the current study examined the effects of genistein, a natural isoflavone present in soybeans, on C. albicans. The genistein-treated C. albicans cells were then exposed to macrophages. Although no inhibition effect on the growth rates of C. albicans was noted an enhancement of the immune response to macrophages has been observed, indicated by phagocytosis and release of cytokines TNF-α and IL-10. The effect of genistein on the enhanced phagocytosis can be mimicked by the fungicides fludioxonil or iprodione, which inhibit the histidine kinase Cos1p and lead to activation of HOG pathway. The western blot results showed a clear phosphorylation of Hog1p in the wild type strain of C. albicans after incubation with genistein. In addition, effects of genistein on the phosphorylation of Hog1p in the histidine kinase mutants Δcos1 and Δsln1 were also observed. Our results thus indicate a new bio-activity of genistein on C. albicans by activation of the HOG pathway of the human pathogen C. albicans.

  7. Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis.

    Science.gov (United States)

    Chen, Ying-Lien; Brand, Alexandra; Morrison, Emma L; Silao, Fitz Gerald S; Bigol, Ursela G; Malbas, Fedelino F; Nett, Jeniel E; Andes, David R; Solis, Norma V; Filler, Scott G; Averette, Anna; Heitman, Joseph

    2011-06-01

    Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.

  8. Calcineurin Controls Drug Tolerance, Hyphal Growth, and Virulence in Candida dubliniensis▿†

    Science.gov (United States)

    Chen, Ying-Lien; Brand, Alexandra; Morrison, Emma L.; Silao, Fitz Gerald S.; Bigol, Ursela G.; Malbas, Fedelino F.; Nett, Jeniel E.; Andes, David R.; Solis, Norma V.; Filler, Scott G.; Averette, Anna; Heitman, Joseph

    2011-01-01

    Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections. PMID:21531874

  9. The Dietary Food Components Capric Acid and Caprylic Acid Inhibit Virulence Factors in Candida albicans Through Multitargeting.

    Science.gov (United States)

    Jadhav, Ashwini; Mortale, Supriya; Halbandge, Shivkrupa; Jangid, Priyanka; Patil, Rajendra; Gade, Wasudev; Kharat, Kiran; Karuppayil, Sankunny Mohan

    2017-11-01

    Capric acid and caprylic acid are the dietary food components. They are found to inhibit the virulence factors like morphogenesis, adhesion, and biofilm formation in the human pathogenic yeast Candida albicans. Our study demonstrated that yeast-to-hyphal signal transduction pathways were affected by capric acid and caprylic acid. The expression profile of genes associated with serum-induced morphogenesis showed reduced expressions of Cdc35, Hwp1, Hst7, and Cph1 by the treatment with both the fatty acids. Cell elongation gene, Ece1, was surprisingly downregulated by 5208-fold by the treatment of caprylic acid. Nrg1 and Tup1, negative regulators of hyphal formation, were overexpressed in presence of capric or caprylic acid. Cell cycle studies revealed that capric and caprylic acids arrested cell cycle at G2/M and S phase. Targeting the virulence factors like yeast-to-hyphal transition is efficacious for treatment of opportunistic fungal infections. This research suggests that both capric and caprylic acid may be effective interventions for treating C. albicans yeast infections.

  10. The antibacterial agent, moxifloxacin inhibits virulence factors of Candida albicans through multitargeting.

    Science.gov (United States)

    Jadhav, Ashwini; Bansode, Bhagyashree; Phule, Datta; Shelar, Amruta; Patil, Rajendra; Gade, Wasudev; Kharat, Kiran; Karuppayil, Sankunny Mohan

    2017-05-01

    Fluoroquinolines are broad spectrum fourth generation antibiotics. Some of the Fluoroquinolines exhibit antifungal activity. We are reporting the potential mechanism of action of a fluoroquinoline antibiotic, moxifloxacin on the growth, morphogenesis and biofilm formation of the human pathogen Candida albicans. Moxifloxacin was found to be Candidacidal in nature. Moxifloxacin seems to inhibit the yeast to Hyphal morphogenesis by affecting signaling pathways. It arrested the cell cycle of C. albicans at S phase. Docking of moxifloxacin with predicted structure of C. albicans DNA Topoisomerase II suggests that moxifloxacin may bind and inhibit the activity of DNA Topoisomerase II in C. albicans. Moxifloxacin could be used as a dual purpose antibiotic for treating mixed infections caused by bacteria as well as C. albicans. In addition chances of developing moxifloxacin resistance in C. albicans are less considering the fact that moxifloxacin may target multiple steps in yeast to hyphal transition in C. albicans.

  11. Therapeutic potential of thiazolidinedione-8 as an antibiofilm agent against Candida albicans.

    Directory of Open Access Journals (Sweden)

    Mark Feldman

    Full Text Available Candida albicans is known as a commensal microorganism but it is also the most common fungal pathogen in humans, causing both mucosal and systemic infections. Biofilm-associated C. albicans infections present clinically important features due to their high levels of resistance to traditional antifungal agents. Quorum sensing is closely associated with biofilm formation and increasing fungal pathogenicity. We investigated the ability of the novel bacterial quorum sensing quencher thiazolidinedione-8 (S-8 to inhibit the formation of, and eradication of mature C. albicans biofilms. In addition, the capability of S-8 to alter fungal adhesion to mammalian cells was checked. S-8 exhibited specific antibiofilm and antiadhesion activities against C. albicans, at four- to eightfold lower concentrations than the minimum inhibitory concentration (MIC. Using fluorescence microscopy, we observed that S-8 dose-dependently reduces C. albicans-GFP binding to RAW macrophages. S-8 at sub-MICs also interfered with fungal morphogenesis by inhibiting the yeast-to-hyphal form transition. In addition, the tested agent strongly affected fungal cell wall characteristics by modulating its hydrophobicity. We evaluated the molecular mode of S-8 antibiofilm and antiadhesion activities using real-time RT-PCR. The expression levels of genes associated with biofilm formation, adhesion and filamentation, HWP1, ALS3 and EAP1, respectively, were dose-dependently downregulated by S-8. Transcript levels of UME6, responsible for long-term hyphal maintenance, were also significantly decreased by the tested agent. Both signaling pathways of hyphal formation-cAMP-PKA and MAPK-were interrupted by S-8. Their upstream general regulator RAS1 was markedly suppressed by S-8. In addition, the expression levels of MAPK cascade components CST20, HST7 and CPH1 were downregulated by S-8. Finally, transcriptional repressors of filament formation, TUP1 and NRG1, were dramatically upregulated by our

  12. The Mkk2 MAPKK Regulates Cell Wall Biogenesis in Cooperation with the Cek1-Pathway in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Elvira Román

    Full Text Available The cell wall integrity pathway (CWI plays an important role in the biogenesis of the cell wall in Candida albicans and other fungi. In the present work, the C. albicans MKK2 gene that encodes the putative MAPKK of this pathway was deleted in different backgrounds and the phenotypes of the resultant mutants were characterised. We show here that Mkk2 mediates the phosphorylation of the Mkc1 MAPK in response to cell wall assembly interfering agents such as zymolyase or tunicamycin and also to oxidative stress. Remarkably, mkk2 and mkc1 mutants display related but distinguishable- cell wall associated phenotypes and differ in the pattern of MAPK phosphorylation under different stress conditions. mkk2 and mkc1 mutants display an altered expression of GSC1, CEK1 and CRH11 genes at different temperatures. Combined deletion of MKK2 with HST7 supports a cooperative role for the Cek1-mediated and CWI pathways in regulating cell wall architecture under vegetative growth. However, and in contrast to Mkc1, Mkk2 does not seem to play a role in the virulence of C. albicans in the mouse systemic model or the Galleria mellonella model of infection.

  13. Dectin-1 is required for miR155 upregulation in murine macrophages in response to Candida albicans.

    Science.gov (United States)

    Agustinho, Daniel Paiva; de Oliveira, Marco Antônio; Tavares, Aldo Henrique; Derengowski, Lorena; Stolz, Valentina; Guilhelmelli, Fernanda; Mortari, Márcia Renata; Kuchler, Karl; Silva-Pereira, Ildinete

    2017-01-02

    The commensal fungal pathogen Candida albicans is a leading cause of lethal systemic infections in immunocompromised patients. One of the main mechanisms of host immune evasion and virulence by this pathogen is the switch from yeast form to hyphal growth morphologies. Micro RNAs (miRNAs), a small regulatory non-coding RNA, has been identified as an important part of the immune response to a wide variety of pathogens. In general, miRNAs act by modulating the intensity of inflammatory responses. miRNAs act by base-paring binding to specific sequences of target mRNAs, generally causing their silencing through mRNA degradation or translational repression. To study the impact of C. albicans cell morphology upon host miRNA expression, we investigated the differential modulation of 9 different immune response-related miRNAs in primary murine bone marrow-derived macrophages (BMDMs) exposed to either yeasts or hyphal forms of Candida albicans. Here, we show that the different growth morphologies induce distinct miRNA expression patterns in BMDMs. Interestingly, our data suggest that the C-Type lectin receptor Dectin-1 is a major PRR that orchestrates miR155 upregulation in a Syk-dependent manner. Our results suggest that PRR-mediating signaling events are key drivers of miRNA-mediated gene regulation during fungal pathogenesis.

  14. Compatibility and incompatibility in hyphal anastomosis of arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Candido Barreto de Novais

    Full Text Available ABSTRACT: Arbuscular mycorrhizal fungi (AMF, which live in symbiosis with 80 % of plants, are not able to grow when separated from their hosts. Spore germination is not host-regulated and germling growth is shortly arrested in the absence of host roots. Germling survival chances may be increased by hyphal fusions (anastomoses, which allow access to nutrients flowing in the extraradical mycelium (ERM. Perfect anastomoses, occurring with high frequency among germlings and the ERM of the same isolate, show protoplasm continuity and disappearance of hyphal walls. A low frequency of perfect fusions has been detected among co-specific genetically different isolates, although fungal nuclei have been consistently detected in all perfect fusions, suggesting active nuclear migration. When plants of different taxa establish symbioses with the same AMF species, anastomoses between ERM spreading from single root systems establish a common mycelium, which is an essential element to plant nutrition and communication. The interaction among mycelia produced by different isolates may also lead to pre-fusion incompatibility which hinders anastomosis formation, or to incompatibility after fusion, which separates the hyphal compartments. Results reported here, obtained by analyses of hyphal compatibility/incompatibility in AMF, suggest that anastomosis formation and establishment of protoplasm flow, fundamental to the maintenance of mycelial physiological and genetic continuity, may affect the fitness of these ecologically important biotrophic fungi.

  15. In vitro effect of malachite green on Candida albicans involves multiple pathways and transcriptional regulators UPC2 and STP2.

    Science.gov (United States)

    Dhamgaye, Sanjiveeni; Devaux, Frederic; Manoharlal, Raman; Vandeputte, Patrick; Shah, Abdul Haseeb; Singh, Ashutosh; Blugeon, Corinne; Sanglard, Dominique; Prasad, Rajendra

    2012-01-01

    In this study, we show that a chemical dye, malachite green (MG), which is commonly used in the fish industry as an antifungal, antiparasitic, and antibacterial agent, could effectively kill Candida albicans and non-C. albicans species. We have demonstrated that Candida cells are susceptible to MG at a very low concentration (MIC that reduces growth by 50% [MIC(50)], 100 ng ml(-1)) and that the effect of MG is independent of known antifungal targets, such as ergosterol metabolism and major drug efflux pump proteins. Transcriptional profiling in response to MG treatment of C. albicans cells revealed that of a total of 207 responsive genes, 167 genes involved in oxidative stress, virulence, carbohydrate metabolism, heat shock, amino acid metabolism, etc., were upregulated, while 37 genes involved in iron acquisition, filamentous growth, mitochondrial respiration, etc., were downregulated. We confirmed experimentally that Candida cells exposed to MG resort to a fermentative mode of metabolism, perhaps due to defective respiration. In addition, we showed that MG triggers depletion of intracellular iron pools and enhances reactive oxygen species (ROS) levels. These effects could be reversed by the addition of iron or antioxidants, respectively. We provided evidence that the antifungal effect of MG is exerted through the transcription regulators UPC2 (regulating ergosterol biosynthesis and azole resistance) and STP2 (regulating amino acid permease genes). Taken together, our transcriptome, genetic, and biochemical results allowed us to decipher the multiple mechanisms by which MG exerts its anti-Candida effects, leading to a metabolic shift toward fermentation, increased generation of ROS, labile iron deprivation, and cell necrosis.

  16. Hyphal walls of isolated lichen fungi

    International Nuclear Information System (INIS)

    Galun, M.; Braun, A.; Frensdorff, A.; Galun, E.

    1976-01-01

    The hyphal walls of three mycobionts, isolated from the lichens Xanthoria parietina, Tornabenia intricata and Sarcogyne sp. were investigated by two techniques: microaudiography of fungal colonies exposed to radioactive carbohydrate precursors; and binding, in vivo, of fluorescein conjugated lectins to hyphal walls of such colonies. N-( 3 H) acetylglucosamine was readily incorporated into tips, young hyphal walls and septa of the three mycobionts and the free-living fungus Trichoderma viride, but not into Phytophthora citrophthora, indicating that chitin is a major component of the mycobionts' hyphal walls. All three mycobionts, but neither of the free-living fungi, incorporated ( 3 H) mannose and ( 3 H) mannitol into their hyphal walls. Fluorescein-conjugated wheat germ agglutinin was bound to the hyphal walls of the three mycobionts and T. viride, but not to the walls of P. citrophthora; the binding pattern was similar to the grain pattern obtained in audiographs after short N-( 3 H) acetylglucosamine labelling. As wheat germ agglutinin binds specifically to chitin oligomers, the lectin binding tests further confirmed that chitin is a mycobiont hyphal wall component. Binding characteristics of several fluorescein-conjugated lectins to the three mycobionts indicated that this technique can yield useful information concerning the chemical composition of hyphal wall surfaces. (orig./AJ) [de

  17. Transcript profiling reveals rewiring of iron assimilation gene expression in Candida albicans and C. dubliniensis.

    LENUS (Irish Health Repository)

    Moran, Gary P

    2012-12-01

    Hyphal growth is repressed in Candida albicans and Candida dubliniensis by the transcription factor Nrg1. Transcript profiling of a C. dubliniensis NRG1 mutant identified a common group of 28 NRG1-repressed genes in both species, including the hypha-specific genes HWP1, ECE1 and the regulator of cell elongation UME6. Unexpectedly, C. dubliniensis NRG1 was required for wild-type levels of expression of 10 genes required for iron uptake including seven ferric reductases, SIT1, FTR1 and RBT5. However, at alkaline pH and during filamentous growth in 10% serum, most of these genes were highly induced in C. dubliniensis. Conversely, RBT5, PGA10, FRE10 and FRP1 did not exhibit induction during hyphal growth when NRG1 is downregulated, indicating that in C. dubliniensis NRG1 is also required for optimal expression of these genes in alkaline environments. In iron-depleted medium at pH 4.5, reduced growth of the NRG1 mutant relative to wild type was observed; however, growth was restored to wild-type levels or greater at pH 6.5, indicating that alkaline induction of iron assimilation gene expression could rescue this phenotype. These data indicate that transcriptional control of iron assimilation and pseudohypha formation has been separated in C. albicans, perhaps promoting growth in a wider range of niches.

  18. Plasma-membrane Cnh1 Na+/H+ antiporter regulates potassium homeostasis in Candida albicans

    Czech Academy of Sciences Publication Activity Database

    Kinclová-Zimmermannová, Olga; Sychrová, Hana

    2007-01-01

    Roč. 153, č. 8 (2007), s. 2603-2612 ISSN 1350-0872 R&D Projects: GA MŠk(CZ) LC531; GA AV ČR KJB5011307 Grant - others:CANTRAIN(XE) MRTN-CT-2004-512481 Institutional research plan: CEZ:AV0Z50110509 Source of funding: R - rámcový projekt EK Keywords : C. albicans * Cnh1 antiporter * potassium homeostasis Subject RIV: EE - Microbiology, Virology Impact factor: 3.110, year: 2007

  19. Phenotypic plasticity regulates Candida albicans interactions and virulence in the vertebrate host

    Directory of Open Access Journals (Sweden)

    Emily M Mallick

    2016-05-01

    Full Text Available Phenotypic diversity is critical to the lifestyles of many microbial species, enabling rapid responses to changes in environmental conditions. In the human fungal pathogen Candida albicans, cells exhibit heritable switching between two phenotypic states, white and opaque, which yield differences in mating, filamentous growth, and interactions with immune cells in vitro. Here, we addressed the in vivo properties of the two cell states in a zebrafish model of infection. Multiple attributes were compared including the stability of phenotypic states, filamentation, virulence, dissemination, and phagocytosis by immune cells, and phenotypes equated across three different host temperatures. We show that both white and opaque cells can establish a lethal systemic infection. The relative virulence of the two cell types is temperature dependent; virulence is similar at 25°C, but at higher temperatures (30 and 33°C white cells are significantly more virulent than opaque cells. Despite the difference in virulence, fungal burdens and dissemination are similar between cells in the two states. Additionally, both white and opaque cells exhibit robust filamentation during infection, and mutants unable to filament show decreased virulence, establishing that this program is critical for pathogenesis in both cell states. Interactions between C. albicans cells and immune cells were compared both in vitro and in vivo. Macrophages and neutrophils preferentially phagocytosed white cells over opaque cells in vitro, and neutrophils also showed preferential phagocytosis of white cells in vivo. Together, these studies distinguish the properties of white and opaque cells in a vertebrate host, and establish that the two cell types demonstrate both important similarities and key differences during infection.

  20. Microevolution of Candida albicans in macrophages restores filamentation in a nonfilamentous mutant.

    Directory of Open Access Journals (Sweden)

    Anja Wartenberg

    2014-12-01

    Full Text Available Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of resistance against antifungals. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is nonfilamentous, as central signaling pathways linking environmental cues to hyphal formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. In addition, the evolved mutant exhibited hyper-virulence in a murine infection model and an altered cell wall composition compared to the cph1Δ/efg1Δ strain. Moreover, the transcriptional regulation of hyphae-associated, and other pathogenicity-related genes became re-responsive to environmental cues in the evolved strain. We went on to identify the causative missense mutation via whole genome- and transcriptome-sequencing: a single nucleotide exchange took place within SSN3 that encodes a component of the Cdk8 module of the Mediator complex, which links transcription factors with the general transcription machinery. This mutation was responsible for the reconnection of the hyphal growth program with environmental signals in the evolved strain and was sufficient to bypass Efg1/Cph1-dependent filamentation. These data demonstrate that even central transcriptional networks can be remodeled very quickly under appropriate selection pressure.

  1. The Mkk2 MAPKK Regulates Cell Wall Biogenesis in Cooperation with the Cek1-Pathway in Candida albicans

    NARCIS (Netherlands)

    Román, Elvira; Alonso-Monge, Rebeca; Miranda Bedate, A.; Pla, Jesús

    2015-01-01

    The cell wall integrity pathway (CWI) plays an important role in the biogenesis of the cell wall in Candida albicans and other fungi. In the present work, the C. albicans MKK2 gene that encodes the putative MAPKK of this pathway was deleted in different backgrounds and the phenotypes of the

  2. Morphological and physiological changes induced by contact-dependent interaction between Candida albicans and Fusobacterium nucleatum

    Science.gov (United States)

    Bor, Batbileg; Cen, Lujia; Agnello, Melissa; Shi, Wenyuan; He, Xuesong

    2016-01-01

    Candida albicans and Fusobacterium nucleatum are well-studied oral commensal microbes with pathogenic potential that are involved in various oral polymicrobial infectious diseases. Recently, we demonstrated that F. nucleatum ATCC 23726 coaggregates with C. albicans SN152, a process mainly mediated by fusobacterial membrane protein RadD and Candida cell wall protein Flo9. The aim of this study was to investigate the potential biological impact of this inter-kingdom interaction. We found that F. nucleatum ATCC 23726 inhibits growth and hyphal morphogenesis of C. albicans SN152 in a contact-dependent manner. Further analysis revealed that the inhibition of Candida hyphal morphogenesis is mediated via RadD and Flo9 protein pair. Using a murine macrophage cell line, we showed that the F. nucleatum-induced inhibition of Candida hyphal morphogenesis promotes C. albicans survival and negatively impacts the macrophage-killing capability of C. albicans. Furthermore, the yeast form of C. albicans repressed F. nucleatum-induced MCP-1 and TNFα production in macrophages. Our study suggests that the interaction between C. albicans and F. nucleatum leads to a mutual attenuation of virulence, which may function to promote a long-term commensal lifestyle within the oral cavity. This finding has significant implications for our understanding of inter-kingdom interaction and may impact clinical treatment strategies. PMID:27295972

  3. Als1 and Als3 regulate the intracellular uptake of copper ions when Candida albicans biofilms are exposed to metallic copper surfaces.

    Science.gov (United States)

    Zheng, Sha; Chang, Wenqiang; Li, Chen; Lou, Hongxiang

    2016-05-01

    Copper surfaces possess efficient antimicrobial effect. Here, we reported that copper surfaces could inactivate Candida albicans biofilms within 40 min. The intracellular reactive oxygen species in C. albicans biofilms were immediately stimulated during the contact of copper surfaces, which might be an important factor for killing the mature biofilms. Copper release assay demonstrated that the copper ions automatically released from the surface of 1 mm thick copper coupons with over 99.9% purity are not the key determinant for the copper-mediated killing action. The susceptibility test to copper surfaces by using C. albicans mutant strains, which were involved in efflux pumps, adhesins, biofilms formation or osmotic stress response showed that als1/als1 and als3/als3 displayed higher resistance to the copper surface contact than other mutants did. The intracellular concentration of copper ions was lower in als1/als1 and als3/als3 than that in wild-type strain. Transcriptional analysis revealed that the expression of copper transporter-related gene, CRP1, was significantly increased in als1/als1, als3/als3, suggesting a potential role of ALS1 and ALS3 in absorbing ions by regulating the expression of CRP1 This study provides a potential application in treating pathogenic fungi by using copper surfaces and uncovers the roles of ALS1 and ALS3 in absorbing copper ions for C. albicans. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. IL-33 priming regulates multiple steps of the neutrophil-mediated anti-Candida albicans response by modulating TLR and dectin-1 signals.

    Science.gov (United States)

    Le, Hongnga T; Tran, Vuvi G; Kim, Wonyoung; Kim, Juyang; Cho, Hong R; Kwon, Byungsuk

    2012-07-01

    IL-33 is known to play an important role in Th2 immunity. In this study, we investigated the effect of IL-33 pretreatment on anti-fungal response using an acute Candida albicans peritoneal infection model. IL-33 pretreatment induced a rapid fungal clearance and markedly reduced the C. albicans infection-associated mortality. The priming effect of IL-33 occurred during multiple steps of the neutrophil-mediated anti-fungal response. First, the anti-fungal effect occurred due to the rapid and massive recruitment of neutrophils to the site of infection as a result of the release of CXCR2 chemokines by peritoneal macrophages and by reversal of the TLR-induced reduction of CXCR2 expression in neutrophils during IL-33 priming. Second, conditioning of neutrophils by IL-33 activated the TLR and dectin-1 signaling pathways, leading to the upregulation of complement receptor 3 expression induced by C. albicans. Upregulated CR3 in turn increased the phagocytosis of opsonized C. albicans and resulted in the production of high levels of reactive oxygen species and the subsequent enhanced killing activity of neutrophils. Taken together, our results suggest that IL-33 can regulate the anti-fungal activity of neutrophils by collaborative modulation of the signaling pathways of different classes of innate immune receptors.

  5. Identification and functional characterization of Rca1, a transcription factor involved in both antifungal susceptibility and host response in Candida albicans.

    Science.gov (United States)

    Vandeputte, Patrick; Pradervand, Sylvain; Ischer, Françoise; Coste, Alix T; Ferrari, Sélène; Harshman, Keith; Sanglard, Dominique

    2012-07-01

    The identification of novel transcription factors associated with antifungal response may allow the discovery of fungus-specific targets for new therapeutic strategies. A collection of 241 Candida albicans transcriptional regulator mutants was screened for altered susceptibility to fluconazole, caspofungin, amphotericin B, and 5-fluorocytosine. Thirteen of these mutants not yet identified in terms of their role in antifungal response were further investigated, and the function of one of them, a mutant of orf19.6102 (RCA1), was characterized by transcriptome analysis. Strand-specific RNA sequencing and phenotypic tests assigned Rca1 as the regulator of hyphal formation through the cyclic AMP/protein kinase A (cAMP/PKA) signaling pathway and the transcription factor Efg1, but also probably through its interaction with a transcriptional repressor, most likely Tup1. The mechanisms responsible for the high level of resistance to caspofungin and fluconazole observed resulting from RCA1 deletion were investigated. From our observations, we propose that caspofungin resistance was the consequence of the deregulation of cell wall gene expression and that fluconazole resistance was linked to the modulation of the cAMP/PKA signaling pathway activity. In conclusion, our large-scale screening of a C. albicans transcription factor mutant collection allowed the identification of new effectors of the response to antifungals. The functional characterization of Rca1 assigned this transcription factor and its downstream targets as promising candidates for the development of new therapeutic strategies, as Rca1 influences host sensing, hyphal development, and antifungal response.

  6. The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans

    Directory of Open Access Journals (Sweden)

    Barbara Koch

    2017-12-01

    Full Text Available The interactions of mitochondria with the endoplasmic reticulum (ER are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure. In the model yeast Saccharomyces cerevisiae, the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans. There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1Δ/Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1Δ/Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP kinase Cek1 is reduced in the gem1Δ/Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans. We propose that ER-mitochondria interactions and the ER

  7. Candida krusei and Candida glabrata reduce the filamentation of Candida albicans by downregulating expression of HWP1 gene.

    Science.gov (United States)

    de Barros, Patrícia Pimentel; Freire, Fernanda; Rossoni, Rodnei Dennis; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

    2017-07-01

    Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.

  8. Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans

    Directory of Open Access Journals (Sweden)

    Ranjith Kumar Manoharan

    2017-08-01

    Full Text Available Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO, which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry, and phenolics were the main constituents. Of these, camphor, fenchone, fenchyl alcohol, α-thujone, and borneol significantly reduced C. albicans biofilm formation. Notably, treatments with CLEO, camphor, or fenchyl alcohol at 0.01% clearly inhibited hyphal formation, and this inhibition appeared to be largely responsible for their antibiofilm effects. Transcriptomic analyses indicated that camphor and fenchyl alcohol downregulated some hypha-specific and biofilm related genes (ECE1, ECE2, RBT1, and EED1. Furthermore, camphor and fenchyl alcohol reduced C. albicans virulence in a Caenorhabditis elegans nematode model. These results demonstrate CLEO, camphor, and fenchyl alcohol might be useful for controlling C. albicans infections.

  9. Candida albicans ISW2 Regulates Chlamydospore Suspensor Cell Formation and Virulence In Vivo in a Mouse Model of Disseminated Candidiasis

    Science.gov (United States)

    Lionakis, Michail S.; Nickerson, Kenneth W.

    2016-01-01

    Formation of chlamydospores by Candida albicans was an established medical diagnostic test to confirm candidiasis before the molecular era. However, the functional role and pathological relevance of this in vitro morphological transition to pathogenesis in vivo remain unclear. We compared the physical properties of in vitro-induced chlamydospores with those of large C. albicans cells purified by density gradient centrifugation from Candida-infected mouse kidneys. The morphological and physical properties of these cells in kidneys of mice infected intravenously with wild type C. albicans confirmed that chlamydospores can form in infected kidneys. A previously reported chlamydospore-null Δisw2/Δisw2 mutant was used to investigate its role in virulence and chlamydospore induction. Virulence of the Δisw2/Δisw2 mutant strain was reduced 3.4-fold compared to wild type C. albicans or the ISW2 reconstituted strain. Altered host inflammatory reactions to the null mutant further indicate that ISW2 is a virulence factor in C. albicans. ISW2 deletion abolished chlamydospore formation within infected mouse kidneys, whereas the reconstituted strain restored chlamydospore formation in kidneys. Under chlamydospore inducing conditions in vitro, deletion of ISW2 significantly delayed chlamydospore formation, and those late induced chlamydospores lacked associated suspensor cells while attaching laterally to hyphae via novel spore-hypha septa. Our findings establish the induction of chlamydospores by C. albicans during mouse kidney colonization. Our results indicate that ISW2 is not strictly required for chlamydospores formation but is necessary for suspensor cell formation. The importance of ISW2 in chlamydospore morphogenesis and virulence may lead to additional insights into morphological differentiation and pathogenesis of C. albicans in the host microenvironment. PMID:27727302

  10. Cigarette Smoke-Exposed Candida albicans Increased Chitin Production and Modulated Human Fibroblast Cell Responses

    Directory of Open Access Journals (Sweden)

    Humidah Alanazi

    2014-01-01

    Full Text Available The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P<0.01 sensitive to oxidation but significantly (P<0.01 resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P<0.01 slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers.

  11. Alternative Mating Type Configurations (a/α versus a/a or α/α) of Candida albicans Result in Alternative Biofilms Regulated by Different Pathways

    Science.gov (United States)

    Srikantha, Thyagarajan; Huang, Guanghua; Garnaas, Adam M.; Soll, David R.

    2011-01-01

    Similar multicellular structures can evolve within the same organism that may have different evolutionary histories, be controlled by different regulatory pathways, and play similar but nonidentical roles. In the human fungal pathogen Candida albicans, a quite extraordinary example of this has occurred. Depending upon the configuration of the mating type locus (a/α versus a/a or α/α), C. albicans forms alternative biofilms that appear similar morphologically, but exhibit dramatically different characteristics and are regulated by distinctly different signal transduction pathways. Biofilms formed by a/α cells are impermeable to molecules in the size range of 300 Da to 140 kDa, are poorly penetrated by human polymorphonuclear leukocytes (PMNs), and are resistant to antifungals. In contrast, a/a or α/α biofilms are permeable to molecules in this size range, are readily penetrated by PMNs, and are susceptible to antifungals. By mutational analyses, a/α biofilms are demonstrated to be regulated by the Ras1/cAMP pathway that includes Ras1→Cdc35→cAMP(Pde2—|)→Tpk2(Tpk1)→Efg1→Tec1→Bcr1, and a/a biofilms by the MAP kinase pathway that includes Mfα→Ste2→ (Ste4, Ste18, Cag1)→Ste11→Hst7→Cek2(Cek1)→Tec1. These observations suggest the hypothesis that while the upstream portion of the newly evolved pathway regulating a/a and α/α cell biofilms was derived intact from the upstream portion of the conserved pheromone-regulated pathway for mating, the downstream portion was derived through modification of the downstream portion of the conserved pathway for a/α biofilm formation. C. albicans therefore forms two alternative biofilms depending upon mating configuration. PMID:21829325

  12. Stage specific assessment of Candida albicans phagocytosis by macrophages identifies cell wall composition and morphogenesis as key determinants.

    Directory of Open Access Journals (Sweden)

    Leanne E Lewis

    Full Text Available Candida albicans is a major life-threatening human fungal pathogen. Host defence against systemic Candida infection relies mainly on phagocytosis of fungal cells by cells of the innate immune system. In this study, we have employed video microscopy, coupled with sophisticated image analysis tools, to assess the contribution of distinct C. albicans cell wall components and yeast-hypha morphogenesis to specific stages of phagocytosis by macrophages. We show that macrophage migration towards C. albicans was dependent on the glycosylation status of the fungal cell wall, but not cell viability or morphogenic switching from yeast to hyphal forms. This was not a consequence of differences in maximal macrophage track velocity, but stems from a greater percentage of macrophages pursuing glycosylation deficient C. albicans during the first hour of the phagocytosis assay. The rate of engulfment of C. albicans attached to the macrophage surface was significantly delayed for glycosylation and yeast-locked morphogenetic mutant strains, but enhanced for non-viable cells. Hyphal cells were engulfed at a slower rate than yeast cells, especially those with hyphae in excess of 20 µm, but there was no correlation between hyphal length and the rate of engulfment below this threshold. We show that spatial orientation of the hypha and whether hyphal C. albicans attached to the macrophage via the yeast or hyphal end were also important determinants of the rate of engulfment. Breaking down the overall phagocytic process into its individual components revealed novel insights into what determines the speed and effectiveness of C. albicans phagocytosis by macrophages.

  13. Stage specific assessment of Candida albicans phagocytosis by macrophages identifies cell wall composition and morphogenesis as key determinants.

    Science.gov (United States)

    Lewis, Leanne E; Bain, Judith M; Lowes, Christina; Gillespie, Collette; Rudkin, Fiona M; Gow, Neil A R; Erwig, Lars-Peter

    2012-01-01

    Candida albicans is a major life-threatening human fungal pathogen. Host defence against systemic Candida infection relies mainly on phagocytosis of fungal cells by cells of the innate immune system. In this study, we have employed video microscopy, coupled with sophisticated image analysis tools, to assess the contribution of distinct C. albicans cell wall components and yeast-hypha morphogenesis to specific stages of phagocytosis by macrophages. We show that macrophage migration towards C. albicans was dependent on the glycosylation status of the fungal cell wall, but not cell viability or morphogenic switching from yeast to hyphal forms. This was not a consequence of differences in maximal macrophage track velocity, but stems from a greater percentage of macrophages pursuing glycosylation deficient C. albicans during the first hour of the phagocytosis assay. The rate of engulfment of C. albicans attached to the macrophage surface was significantly delayed for glycosylation and yeast-locked morphogenetic mutant strains, but enhanced for non-viable cells. Hyphal cells were engulfed at a slower rate than yeast cells, especially those with hyphae in excess of 20 µm, but there was no correlation between hyphal length and the rate of engulfment below this threshold. We show that spatial orientation of the hypha and whether hyphal C. albicans attached to the macrophage via the yeast or hyphal end were also important determinants of the rate of engulfment. Breaking down the overall phagocytic process into its individual components revealed novel insights into what determines the speed and effectiveness of C. albicans phagocytosis by macrophages.

  14. Differential filamentation of Candida albicans and Candida dubliniensis Is governed by nutrient regulation of UME6 expression.

    LENUS (Irish Health Repository)

    O'Connor, Leanne

    2010-09-01

    Candida dubliniensis is closely related to Candida albicans; however, it is responsible for fewer infections in humans and is less virulent in animal models of infection. C. dubliniensis forms fewer hyphae in vivo, and this may contribute to its reduced virulence. In this study we show that, unlike C. albicans, C. dubliniensis fails to form hyphae in yeast extract-peptone-dextrose (YPD) medium supplemented with 10% (vol\\/vol) fetal calf serum (YPDS medium). However, C. dubliniensis filaments in water plus 10% (vol\\/vol) fetal calf serum (WS), and this filamentation is inhibited by the addition of peptone and glucose. Repression of filamentation in YPDS medium could be partly overcome by preculture in synthetic Lee\\'s medium. Unlike C. albicans, inoculation of C. dubliniensis in YPDS medium did not result in increased UME6 transcription. However, >100-fold induction of UME6 was observed when C. dubliniensis was inoculated in nutrient-poor WS medium. The addition of increasing concentrations of peptone to WS medium had a dose-dependent effect on reducing UME6 expression. Transcript profiling of C. dubliniensis hyphae in WS medium identified a starvation response involving expression of genes in the glyoxylate cycle and fatty acid oxidation. In addition, a core, shared transcriptional response with C. albicans could be identified, including expression of virulence-associated genes including SAP456, SAP7, HWP1, and SOD5. Preculture in nutrient-limiting medium enhanced adherence of C. dubliniensis, epithelial invasion, and survival following coculture with murine macrophages. In conclusion, C. albicans, unlike C. dubliniensis, appears to form hyphae in liquid medium regardless of nutrient availability, which may account for its increased capacity to cause disease in humans.

  15. Differential filamentation of Candida albicans and Candida dubliniensis Is governed by nutrient regulation of UME6 expression.

    Science.gov (United States)

    O'Connor, Leanne; Caplice, Nicole; Coleman, David C; Sullivan, Derek J; Moran, Gary P

    2010-09-01

    Candida dubliniensis is closely related to Candida albicans; however, it is responsible for fewer infections in humans and is less virulent in animal models of infection. C. dubliniensis forms fewer hyphae in vivo, and this may contribute to its reduced virulence. In this study we show that, unlike C. albicans, C. dubliniensis fails to form hyphae in yeast extract-peptone-dextrose (YPD) medium supplemented with 10% (vol/vol) fetal calf serum (YPDS medium). However, C. dubliniensis filaments in water plus 10% (vol/vol) fetal calf serum (WS), and this filamentation is inhibited by the addition of peptone and glucose. Repression of filamentation in YPDS medium could be partly overcome by preculture in synthetic Lee's medium. Unlike C. albicans, inoculation of C. dubliniensis in YPDS medium did not result in increased UME6 transcription. However, >100-fold induction of UME6 was observed when C. dubliniensis was inoculated in nutrient-poor WS medium. The addition of increasing concentrations of peptone to WS medium had a dose-dependent effect on reducing UME6 expression. Transcript profiling of C. dubliniensis hyphae in WS medium identified a starvation response involving expression of genes in the glyoxylate cycle and fatty acid oxidation. In addition, a core, shared transcriptional response with C. albicans could be identified, including expression of virulence-associated genes including SAP456, SAP7, HWP1, and SOD5. Preculture in nutrient-limiting medium enhanced adherence of C. dubliniensis, epithelial invasion, and survival following coculture with murine macrophages. In conclusion, C. albicans, unlike C. dubliniensis, appears to form hyphae in liquid medium regardless of nutrient availability, which may account for its increased capacity to cause disease in humans.

  16. Calcium homeostasis is required for contact-dependent helical and sinusoidal tip growth in Candida albicans hyphae

    OpenAIRE

    Brand, Alexandra; Lee, Keunsook; Veses, Veronica; Gow, Neil A R

    2009-01-01

    Hyphae of the dimorphic fungus, Candida albicans, exhibit directional tip responses when grown in contact with surfaces. On hard surfaces or in liquid media, the trajectory of hyphal growth is typically linear, with tip re-orientation events limited to encounters with topographical features (thigmotropism). In contrast, when grown on semisolid surfaces, the tips of C. albicans hyphae grow in an oscillatory manner to form regular two-dimensional sinusoidal curves and three-dimensional helices....

  17. Canine intestinal histoplasmosis containing hyphal forms.

    Science.gov (United States)

    Schumacher, Loni L; Love, Brenda C; Ferrell, Mark; DeSilva, Udaya; Fernando, Ruchika; Ritchey, Jerry W

    2013-03-01

    A 12-year-old intact male Miniature Schnauzer dog with chronic diarrhea that was unresponsive to empirical treatment was presented to a referring veterinarian. A laparotomy was performed, and formalin-fixed biopsies of duodenum, jejunum, and colon were sent to Oklahoma Animal Disease Diagnostic Laboratory for evaluation. Histologic examination revealed a severe, diffuse, granulomatous enteritis and colitis with intralesional yeast and hyphal forms. Grocott methenamine silver stains revealed short, aseptate hyphae co-mingled with 2-8 µm, oval to round yeast organisms consistent with Histoplasma capsulatum. The atypical presentation of both yeast and hyphal forms prompted identification of the organism. Direct sequencing of a polymerase chain reaction product from paraffin-embedded intestinal samples confirmed the presence of Ajellomyces capsulatus with a homology over 99% to several sequences in GenBank. Ajellomyces capsulatus is the holomorphic name for H. capsulatum. Therefore, the mycelial form of a dimorphic fungus such as H. capsulatum can coexist with yeast cells within lesions of histoplasmosis. Following diagnosis, the dog was treated with itraconazole for 6 months and has improved.

  18. Contact-induced apical asymmetry drives the thigmotropic responses of Candida albicans hyphae

    Science.gov (United States)

    Thomson, Darren D; Wehmeier, Silvia; Byfield, FitzRoy J; Janmey, Paul A; Caballero-Lima, David; Crossley, Alison; Brand, Alexandra C

    2015-01-01

    Filamentous hyphae of the human pathogen, Candida albicans, invade mucosal layers and medical silicones. In vitro, hyphal tips reorient thigmotropically on contact with small obstacles. It is not known how surface topography is sensed but hyphae lacking the cortical marker, Rsr1/Bud1, are unresponsive. We show that, on surfaces, the morphology of hyphal tips and the position of internal polarity protein complexes are asymmetrically skewed towards the substratum and biased towards the softer of two surfaces. In nano-fabricated chambers, the Spitzenkörper (Spk) responded to touch by translocating across the apex towards the point of contact, where its stable maintenance correlated with contour-following growth. In the rsr1Δ mutant, the position of the Spk meandered and these responses were attenuated. Perpendicular collision caused lateral Spk oscillation within the tip until after establishment of a new growth axis, suggesting Spk position does not predict the direction of growth in C. albicans. Acute tip reorientation occurred only in cells where forward growth was countered by hyphal friction sufficient to generate a tip force of ∼ 8.7 μN (1.2 MPa), more than that required to penetrate host cell membranes. These findings suggest mechanisms through which the organization of hyphal tip growth in C. albicans facilitates the probing, penetration and invasion of host tissue. PMID:25262778

  19. Candida glabrata Binding to Candida albicans Hyphae Enables Its Development in Oropharyngeal Candidiasis

    Science.gov (United States)

    Tati, Swetha; Davidow, Peter; McCall, Andrew; Hwang-Wong, Elizabeth; Rojas, Isolde G.; Cormack, Brendan; Edgerton, Mira

    2016-01-01

    Pathogenic mechanisms of Candida glabrata in oral candidiasis, especially because of its inability to form hyphae, are understudied. Since both Candida albicans and C. glabrata are frequently co-isolated in oropharyngeal candidiasis (OPC), we examined their co-adhesion in vitro and observed adhesion of C. glabrata only to C. albicans hyphae microscopically. Mice were infected sublingually with C. albicans or C. glabrata individually, or with both species concurrently, to study their ability to cause OPC. Infection with C. glabrata alone resulted in negligible infection of tongues; however, colonization by C. glabrata was increased by co-infection or a pre-established infection with C. albicans. Furthermore, C. glabrata required C. albicans for colonization of tongues, since decreasing C. albicans burden with fluconazole also reduced C. glabrata. C. albicans hyphal wall adhesins Als1 and Als3 were important for in vitro adhesion of C. glabrata and to establish OPC. C. glabrata cell wall protein coding genes EPA8, EPA19, AWP2, AWP7, and CAGL0F00181 were implicated in mediating adhesion to C. albicans hyphae and remarkably, their expression was induced by incubation with germinated C. albicans. Thus, we found a near essential requirement for the presence of C. albicans for both initial colonization and establishment of OPC infection by C. glabrata. PMID:27029023

  20. Candida glabrata Binding to Candida albicans Hyphae Enables Its Development in Oropharyngeal Candidiasis.

    Directory of Open Access Journals (Sweden)

    Swetha Tati

    2016-03-01

    Full Text Available Pathogenic mechanisms of Candida glabrata in oral candidiasis, especially because of its inability to form hyphae, are understudied. Since both Candida albicans and C. glabrata are frequently co-isolated in oropharyngeal candidiasis (OPC, we examined their co-adhesion in vitro and observed adhesion of C. glabrata only to C. albicans hyphae microscopically. Mice were infected sublingually with C. albicans or C. glabrata individually, or with both species concurrently, to study their ability to cause OPC. Infection with C. glabrata alone resulted in negligible infection of tongues; however, colonization by C. glabrata was increased by co-infection or a pre-established infection with C. albicans. Furthermore, C. glabrata required C. albicans for colonization of tongues, since decreasing C. albicans burden with fluconazole also reduced C. glabrata. C. albicans hyphal wall adhesins Als1 and Als3 were important for in vitro adhesion of C. glabrata and to establish OPC. C. glabrata cell wall protein coding genes EPA8, EPA19, AWP2, AWP7, and CAGL0F00181 were implicated in mediating adhesion to C. albicans hyphae and remarkably, their expression was induced by incubation with germinated C. albicans. Thus, we found a near essential requirement for the presence of C. albicans for both initial colonization and establishment of OPC infection by C. glabrata.

  1. Streptococcus mutans Can Modulate Biofilm Formation and Attenuate the Virulence of Candida albicans

    Science.gov (United States)

    Barbosa, Júnia Oliveira; Rossoni, Rodnei Dennis; Vilela, Simone Furgeri Godinho; de Alvarenga, Janaína Araújo; Velloso, Marisol dos Santos; Prata, Márcia Cristina de Azevedo; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos

    2016-01-01

    Streptococcus mutans and Candida albicans are found together in the oral biofilms on dental surfaces, but little is known about the ecological interactions between these species. Here, we studied the effects of S. mutans UA159 on the growth and pathogencity of C. albicans. Initially, the effects of S. mutans on the biofilm formation and morphogenesis of C. albicans were tested in vitro. Next, we investigate the influence of S. mutans on pathogenicity of C. albicans using in vivo host models, in which the experimental candidiasis was induced in G. mellonella larvae and analyzed by survival curves, C. albicans count in hemolymph, and quantification of hyphae in the host tissues. In all the tests, we evaluated the direct effects of S. mutans cells, as well as the indirect effects of the subproducts secreted by this microorganism using a bacterial culture filtrate. The in vitro analysis showed that S. mutans cells favored biofilm formation by C. albicans. However, a reduction in biofilm viable cells and inhibition of hyphal growth was observed when C. albicans was in contact with the S. mutans culture filtrate. In the in vivo study, injection of S. mutans cells or S. mutans culture filtrate into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, a reduction in hyphal formation was observed in larval tissues when C. albicans was associated with S. mutans culture filtrate. These findings suggest that S. mutans can secrete subproducts capable to inhibit the biofilm formation, morphogenesis and pathogenicity of C. albicans, attenuating the experimental candidiasis in G. mellonella model. PMID:26934196

  2. Stress-associated endoplasmic reticulum protein 1 (SERP1) and Atg8 synergistically regulate unfolded protein response (UPR) that is independent on autophagy in Candida albicans.

    Science.gov (United States)

    Li, Jianrong; Yu, Qilin; Zhang, Bing; Xiao, Chenpeng; Ma, Tianyu; Yi, Xiao; Liang, Chao; Li, Mingchun

    2018-03-06

    Cellular stresses could activate several response processes, such as the unfolded protein response (UPR), autophagy and oxidative stress response to restore cellular homeostasis or render cell death. Herein, we identified the Candida albicans stress-associated endoplasmic reticulum protein 1 (SERP1), also known as Ysy6, which was involved in endoplasmic reticulum (ER) stress response. We found that deletion of both SERP1/YSY6 and ATG8 led to hypersensitivity to tunicamycin (TN), and resulted in severe mitochondrial dysfunction under this stress. UPR reporting systems illustrated that the double mutation attenuated splicing of HAC1 mRNA, followed by decreased level of UPR activation. In addition, the atg8Δ/Δ ysy6Δ/Δ double mutant had normal autophagic degradation of the ER component Sec63 under ER stress, suggesting that SERP1/Ysy6 and Atg8 synergistically regulated UPR that is independent on autophagy. We also found that deletion of both SERP1/YSY6 and ATG8 caused the loss of virulence. This study reveals the important role of SERP1/Ysy6 and Atg8 in ER stress response and virulence in C. albicans. Copyright © 2018. Published by Elsevier GmbH.

  3. Triclosan antagonizes fluconazole activity against Candida albicans.

    LENUS (Irish Health Repository)

    Higgins, J

    2012-01-01

    Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg\\/L. However, at subinhibitory concentrations (0.5-2 mg\\/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes.

  4. Triclosan Antagonizes Fluconazole Activity against Candida albicans

    Science.gov (United States)

    Higgins, J.; Pinjon, E.; Oltean, H.N.; White, T.C.; Kelly, S.L.; Martel, C.M.; Sullivan, D.J.; Coleman, D.C.; Moran, G.P.

    2012-01-01

    Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg/L. However, at subinhibitory concentrations (0.5-2 mg/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes. PMID:21972257

  5. Impact of Environmental Conditions on the Form and Function of Candida albicans Biofilms

    Science.gov (United States)

    Daniels, Karla J.; Park, Yang-Nim; Srikantha, Thyagarajan; Pujol, Claude

    2013-01-01

    Candida albicans, like other pathogens, can form complex biofilms on a variety of substrates. However, as the number of studies of gene regulation, architecture, and pathogenic traits of C. albicans biofilms has increased, so have differences in results. This suggests that depending upon the conditions employed, biofilms may vary widely, thus hampering attempts at a uniform description. Gene expression studies suggest that this may be the case. To explore this hypothesis further, we compared the architectures and traits of biofilms formed in RPMI 1640 and Spider media at 37°C in air. Biofilms formed by a/α cells in the two media differed to various degrees in cellular architecture, matrix deposition, penetrability by leukocytes, fluconazole susceptibility, and the facilitation of mating. Similar comparisons of a/a cells in the two media, however, were made difficult given that in air, although a/a cells form traditional biofilms in RPMI medium, they form polylayers composed primarily of yeast cells in Spider medium. These polylayers lack an upper hyphal/matrix region, are readily penetrated by leukocytes, are highly fluconazole susceptible, and do not facilitate mating. If, however, air is replaced with 20% CO2, a/a cells make a biofilm in Spider medium similar architecturally to that of a/α cells, which facilitates mating. A second, more cursory comparison is made between the disparate cellular architectures of a/a biofilms formed in air in RPMI and Lee's media. The results demonstrate that C. albicans forms very different types of biofilms depending upon the composition of the medium, level of CO2 in the atmosphere, and configuration of the MTL locus. PMID:23954841

  6. Time-lapse video microscopy and image analysis of adherence and growth patterns of Candida albicans strains.

    Science.gov (United States)

    Nagy, Gabor; Hennig, Grant W; Petrenyi, Katalin; Kovacs, Laszlo; Pocsi, Istvan; Dombradi, Viktor; Banfalvi, Gaspar

    2014-06-01

    Digital image analysis of high time resolution video microscopy was used to investigate hyphal growth dynamics in different Candida albicans strains. The effects of the quorum sensing molecules tyrosol and farnesol, the deletion of the fungus specific protein phosphatase Z1 CaPPZ1), and the hypha-specific cyclin (HGC1) genes were analyzed by this method. Our system monitored cell growth in a CO2 incubator under near-physiological conditions and measured three major parameters under the following stringent conditions: (a) the time of yeast cell adherence, (b) the time of hyphal outgrowth, and (c) the rate of hyphal growth. This method showed that hyphal extension of wild-type SC5314 cells was accelerated by tyrosol and inhibited by farnesol. Hyphal growth rate was moderately lower in cappz1 and strongly reduced in hgc1 mutants. In addition, tyrosol treatment caused a firm adherence, while farnesol treatment and hgc1 mutation prevented the adherence of yeast cells to the surface of the culture flask. Transition from yeast-to-hyphal state was faster after tyrosol treatment, while it was reduced in farnesol-treated cells as well as in the cappz1 and hgc1 mutants. Our data confirm the notion that the attachment of yeast cells, the yeast-to-hyphal transition, and hyphal growth rate are closely related processes. Time-lapse video microscopy combined with image analysis offers a convenient and reliable method of testing chemicals, including potential drug candidates, and genetic manipulations on the dynamic morphological changes in C. albicans strains.

  7. Comparative transcript profiling of Candida albicans and Candida dubliniensis identifies SFL2, a C. albicans gene required for virulence in a reconstituted epithelial infection model.

    LENUS (Irish Health Repository)

    Spiering, Martin J

    2010-02-01

    Candida albicans and Candida dubliniensis are closely related species displaying differences in virulence and genome content, therefore providing potential opportunities to identify novel C. albicans virulence genes. C. albicans gene arrays were used for comparative analysis of global gene expression in the two species in reconstituted human oral epithelium (RHE). C. albicans (SC5314) showed upregulation of hypha-specific and virulence genes within 30 min postinoculation, coinciding with rapid induction of filamentation and increased RHE damage. C. dubliniensis (CD36) showed no detectable upregulation of hypha-specific genes, grew as yeast, and caused limited RHE damage. Several genes absent or highly divergent in C. dubliniensis were upregulated in C. albicans. One such gene, SFL2 (orf19.3969), encoding a putative heat shock factor, was deleted in C. albicans. DeltaDeltasfl2 cells failed to filament under a range of hypha-inducing conditions and exhibited greatly reduced RHE damage, reversed by reintroduction of SFL2 into the DeltaDeltasfl2 strain. Moreover, SFL2 overexpression in C. albicans triggered hyphal morphogenesis. Although SFL2 deletion had no apparent effect on host survival in the murine model of systemic infection, DeltaDeltasfl2 strain-infected kidney tissues contained only yeast cells. These results suggest a role for SFL2 in morphogenesis and an indirect role in C. albicans pathogenesis in epithelial tissues.

  8. Cytokines regulate complement receptor immunoglobulin expression and phagocytosis of Candida albicans in human macrophages: A control point in anti-microbial immunity.

    Science.gov (United States)

    Munawara, Usma; Small, Annabelle G; Quach, Alex; Gorgani, Nick N; Abbott, Catherine A; Ferrante, Antonio

    2017-06-22

    Complement Receptor Immunoglobulin (CRIg), selectively expressed by macrophages, plays an important role in innate immunity by promoting phagocytosis of bacteria. Thus modulation of CRIg on macrophages by cytokines can be an important mechanism by which cytokines regulate anti-microbial immunity. The effects of the cytokines, tumor necrosis factor, transforming growth factor-β1, interferon-γ, interleukin (IL)-4, IL-13, IL-10, IL-1β, IL-6, lymphotoxin-α, macrophage-colony stimulating factor (M-CSF) and GM-CSF on CRIg expression were examined in human macrophages. We demonstrated that cytokines regulated the CRIg expression on macrophages during their development from monocytes in culture at the transcriptional level using qPCR and protein by Western blotting. Both CRIg spliced forms (Long and Short), were similarly regulated by cytokines. Direct addition of cytokines to matured CRIg+ macrophages also changed CRIg mRNA expression, suggesting that cytokines control macrophage function via CRIg, at two checkpoints. Interestingly the classical complement receptors, CR3 and CR4 were differentially regulated by cytokines. The changes in CRIg but not CR3/CR4 mRNA expression correlated with ability to phagocytose Candida albicans by macrophages. These findings suggest that CRIg is likely to be a control point in infection and immunity through which cytokines can mediate their effects, and is differentially regulated from CR3 and CR4 by cytokines.

  9. Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans

    Science.gov (United States)

    Douglas, Lois M.; Konopka, James. B.

    2017-01-01

    Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans. PMID:26920878

  10. Bacterial GtfB Augments Candida albicans Accumulation in Cross-Kingdom Biofilms.

    Science.gov (United States)

    Ellepola, K; Liu, Y; Cao, T; Koo, H; Seneviratne, C J

    2017-09-01

    Streptococcus mutans is a biofilm-forming oral pathogen commonly associated with dental caries. Clinical studies have shown that S. mutans is often detected with Candida albicans in early childhood caries. Although the C. albicans presence has been shown to enhance bacterial accumulation in biofilms, the influence of S. mutans on fungal biology in this mixed-species relationship remains largely uncharacterized. Therefore, we aimed to investigate how the presence of S. mutans influences C. albicans biofilm development and coexistence. Using a newly established haploid biofilm model of C. albicans, we found that S. mutans augmented haploid C. albicans accumulation in mixed-species biofilms. Similarly, diploid C. albicans also showed enhanced biofilm formation in the presence of S. mutans. Surprisingly, the presence of S. mutans restored the biofilm-forming ability of C. albicans bcr1Δ mutant and bcr1Δ/Δ mutant, which is known to be severely defective in biofilm formation when grown as single species. Moreover, C. albicans hyphal growth factor HWP1 as well as ALS1 and ALS3, which are also involved in fungal biofilm formation, were upregulated in the presence of S. mutans. Subsequently, we found that S. mutans-derived glucosyltransferase B (GtfB) itself can promote C. albicans biofilm development. Interestingly, GtfB was able to increase the expression of HWP1, ALS1, and ALS3 genes in the C. albicans diploid wild-type SC5314 and bcr1Δ/Δ, leading to enhanced fungal biofilms. Hence, the present study demonstrates that a bacterial exoenzyme (GtfB) augments the C. albicans counterpart in mixed-species biofilms through a BCR1-independent mechanism. This novel finding may explain the mutualistic role of S. mutans and C. albicans in cariogenic biofilms.

  11. Candida albicans pathogenicity mechanisms

    OpenAIRE

    Mayer, Fran?ois L.; Wilson, Duncan; Hube, Bernhard

    2013-01-01

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasi...

  12. Infection-associated genes of Candida albicans.

    Science.gov (United States)

    Hube, Bernhard

    2006-08-01

    Advances in the medical treatment of life-threatening disorders have increased the population of patients that are more susceptible to opportunistic microbial infections, such as those caused by the Candida species, in particular Candida albicans. This fungus normally belongs to the microbial flora but may cause a range of diseases from superficial to disseminated. What exactly causes the transition from commensalism to pathogenesis is not clear and how this fungus switches from a commensal mode of growth to a parasitic lifestyle remains unknown. Identifying the genes and factors essential for the different stages of C. albicans infections will not only help understanding of the infection process but also provide information about those fungal factors that have to be inhibited, and those parts of the immune system that have to be stimulated, in order to control or prevent infections. Furthermore, knowledge of those genes whose expression is associated with infection but not commensalism may provide valuable information to improve our diagnostic tools. A number of methodologies and models have already been used to identify infection-associated genes. In addition to genes encoding classical virulence determinants, such as those involved in interactions with the immune system and immune evasion, scientists have monitored the expression of genes involved in nutrient acquisition, metabolism, stress response, physical interaction and hyphal formation in infection models and have begun to elucidate the roles of these genes.

  13. Expression levels and subcellular localization of Bcy1p in Candida albicans mutant strains devoid of one BCY1 allele results in a defective morphogenetic behavior.

    Science.gov (United States)

    Giacometti, Romina; Souto, Guadalupe; Silberstein, Susana; Giasson, Luc; Cantore, María Leonor; Passeron, Susana

    2006-01-01

    We investigated expression, functionality and subcellular localization of C. albicans Bcy1p, the PKA regulatory subunit, in mutant strains having one BCY1 allele fused to a green fluorescent protein (GFP). DE-52 column chromatography of soluble extracts of yeast cells from strains bearing one BCY1 allele (fused or not to GFP) showed co-elution of Bcy1p and Bcy1p-GFP with phosphotransferase activity, suggesting that interaction between regulatory and catalytic subunits was not impaired by the GFP tag. Subcellular localization of Bcy1p-GFP supports our previous hypothesis on the nuclear localization of the regulatory subunit, which can thus tether the PKA catalytic subunit to the nucleus. Protein modeling of CaBcy1p, showed that the fusion of the GFP tag to Bcy1p C-terminus did not significantly disturb its proper folding. Bcy1p levels in mutant strains having one or both BCY1 alleles, led us to establish a direct correlation between the amount of protein and the number of alleles, indicating that deletion of one BCY1 allele is not fully compensated by overexpression of the other. The morphogenetic behavior of several C. albicans mutant strains bearing one or both BCY1 alleles, in a wild-type and in a TPK2 null genetic background, was assessed in N-acetylglucosamine (GlcNAc) liquid medium at 37 degrees C. Strains with one BCY1 allele tagged or not, behaved similarly, displaying pseudohyphae and true hyphae. In contrast, hyphal morphology was almost exclusive in strains having both BCY1 alleles, irrespective of the GFP insertion. It can be inferred that a tight regulation of PKA activity is needed for hyphal growth.

  14. Essential Functional Modules for Pathogenic and Defensive Mechanisms in Candida albicans Infections

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    Yu-Chao Wang

    2014-01-01

    Full Text Available The clinical and biological significance of the study of fungal pathogen Candida albicans (C. albicans has markedly increased. However, the explicit pathogenic and invasive mechanisms of such host-pathogen interactions have not yet been fully elucidated. Therefore, the essential functional modules involved in C. albicans-zebrafish interactions were investigated in this study. Adopting a systems biology approach, the early-stage and late-stage protein-protein interaction (PPI networks for both C. albicans and zebrafish were constructed. By comparing PPI networks at the early and late stages of the infection process, several critical functional modules were identified in both pathogenic and defensive mechanisms. Functional modules in C. albicans, like those involved in hyphal morphogenesis, ion and small molecule transport, protein secretion, and shifts in carbon utilization, were seen to play important roles in pathogen invasion and damage caused to host cells. Moreover, the functional modules in zebrafish, such as those involved in immune response, apoptosis mechanisms, ion transport, protein secretion, and hemostasis-related processes, were found to be significant as defensive mechanisms during C. albicans infection. The essential functional modules thus determined could provide insights into the molecular mechanisms of host-pathogen interactions during the infection process and thereby devise potential therapeutic strategies to treat C. albicans infection.

  15. Essential functional modules for pathogenic and defensive mechanisms in Candida albicans infections.

    Science.gov (United States)

    Wang, Yu-Chao; Tsai, I-Chun; Lin, Che; Hsieh, Wen-Ping; Lan, Chung-Yu; Chuang, Yung-Jen; Chen, Bor-Sen

    2014-01-01

    The clinical and biological significance of the study of fungal pathogen Candida albicans (C. albicans) has markedly increased. However, the explicit pathogenic and invasive mechanisms of such host-pathogen interactions have not yet been fully elucidated. Therefore, the essential functional modules involved in C. albicans-zebrafish interactions were investigated in this study. Adopting a systems biology approach, the early-stage and late-stage protein-protein interaction (PPI) networks for both C. albicans and zebrafish were constructed. By comparing PPI networks at the early and late stages of the infection process, several critical functional modules were identified in both pathogenic and defensive mechanisms. Functional modules in C. albicans, like those involved in hyphal morphogenesis, ion and small molecule transport, protein secretion, and shifts in carbon utilization, were seen to play important roles in pathogen invasion and damage caused to host cells. Moreover, the functional modules in zebrafish, such as those involved in immune response, apoptosis mechanisms, ion transport, protein secretion, and hemostasis-related processes, were found to be significant as defensive mechanisms during C. albicans infection. The essential functional modules thus determined could provide insights into the molecular mechanisms of host-pathogen interactions during the infection process and thereby devise potential therapeutic strategies to treat C. albicans infection.

  16. Genomic and Phenotypic Variation in Morphogenetic Networks of Two Candida albicans Isolates Subtends Their Different Pathogenic Potential

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    Duccio Cavalieri

    2018-01-01

    Full Text Available The transition from commensalism to pathogenicity of Candida albicans reflects both the host inability to mount specific immune responses and the microorganism’s dimorphic switch efficiency. In this study, we used whole genome sequencing and microarray analysis to investigate the genomic determinants of the phenotypic changes observed in two C. albicans clinical isolates (YL1 and YQ2. In vitro experiments employing epithelial, microglial, and peripheral blood mononuclear cells were thus used to evaluate C. albicans isolates interaction with first line host defenses, measuring adhesion, susceptibility to phagocytosis, and induction of secretory responses. Moreover, a murine model of peritoneal infection was used to compare the in vivo pathogenic potential of the two isolates. Genome sequence and gene expression analysis of C. albicans YL1 and YQ2 showed significant changes in cellular pathways involved in environmental stress response, adhesion, filamentous growth, invasiveness, and dimorphic transition. This was in accordance with the observed marked phenotypic differences in biofilm production, dimorphic switch efficiency, cell adhesion, invasion, and survival to phagocyte-mediated host defenses. The mutations in key regulators of the hyphal growth pathway in the more virulent strain corresponded to an overall greater number of budding yeast cells released. Compared to YQ2, YL1 consistently showed enhanced pathogenic potential, since in vitro, it was less susceptible to ingestion by phagocytic cells and more efficient in invading epithelial cells, while in vivo YL1 was more effective than YQ2 in recruiting inflammatory cells, eliciting IL-1β response and eluding phagocytic cells. Overall, these results indicate an unexpected isolate-specific variation in pathways important for host invasion and colonization, showing how the genetic background of C. albicans may greatly affect its behavior both in vitro and in vivo. Based on this approach, we

  17. Identification of small molecules that disrupt vacuolar function in the pathogen Candida albicans.

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    Helene Tournu

    Full Text Available The fungal vacuole is a large acidified organelle that performs a variety of cellular functions. At least a sub-set of these functions are crucial for pathogenic species of fungi, such as Candida albicans, to survive within and invade mammalian tissue as mutants with severe defects in vacuolar biogenesis are avirulent. We therefore sought to identify chemical probes that disrupt the normal function and/or integrity of the fungal vacuole to provide tools for the functional analysis of this organelle as well as potential experimental therapeutics. A convenient indicator of vacuolar integrity based upon the intracellular accumulation of an endogenously produced pigment was adapted to identify Vacuole Disrupting chemical Agents (VDAs. Several chemical libraries were screened and a set of 29 compounds demonstrated to reproducibly cause loss of pigmentation, including 9 azole antifungals, a statin and 3 NSAIDs. Quantitative analysis of vacuolar morphology revealed that (excluding the azoles a sub-set of 14 VDAs significantly alter vacuolar number, size and/or shape. Many C. albicans mutants with impaired vacuolar function are deficient in the formation of hyphal elements, a process essential for its pathogenicity. Accordingly, all 14 VDAs negatively impact C. albicans hyphal morphogenesis. Fungal selectivity was observed for approximately half of the VDA compounds identified, since they did not alter the morphology of the equivalent mammalian organelle, the lysosome. Collectively, these compounds comprise of a new collection of chemical probes that directly or indirectly perturb normal vacuolar function in C. albicans.

  18. Thigmotropism and stretch-activated channels in the pathogenic fungus Candida albicans.

    Science.gov (United States)

    Watts, H J; Véry, A A; Perera, T H; Davies, J M; Gow, N A

    1998-03-01

    The direction of growth of hyphae of the pathogenic fungus Candida albicans responds thigmotropically to surface contours by following scratches, ridges and grooves and by penetrating pores. Here it is shown that the thigmotropic response to ridges is attenuated by GdCl3 and verapamil [blockers of stretch-activated (SA) ion channels and L-type calcium channels, respectively]. At low concentrations, both compounds reduced the percentage of hyphae reorienting on contact with a ridge without markedly affecting hyphal extension rate, suggesting a possible role for SA or other calcium channels in the transduction of the thigmotropic response. In addition, patch-clamp recordings demonstrated SA channel activity in the plasma membrane of both yeast and hyphal cells of C. albicans. Two distinct SA channels with conductances of 54 pS and 20-25 pS in 200 mM KCl were observed in protoplasts from yeast cells and one channel of 51 pS was found in protoplasts from hyphal cells.

  19. Germ tube-specific antigens of Candida albicans cell walls

    International Nuclear Information System (INIS)

    Sundstrom, P.R.

    1986-01-01

    Studies were performed to characterize the surface differences between blastospores and germ tubes of the pathogenic, dimorphic yeast, Candida albicans, and to identify components of yeast cells responsible for these differences. Investigation of surfaces differences of the two growth forms was facilitated by the production of rabbit antiserum prepared against Formalin-treated yeast possessing germ tubes. To prepare antiserum specific for germ tubes, this serum was adsorbed with stationary phase blastospores. Whereas the unadsorbed antiserum reacted with both blastospore and germ tube forms by immunofluorescence and Enzyme-Linked Immunosorbent Assay, the adsorbed antiserum did not react with blastospores but detected germ tube-specific antigens in hyphal forms. The differences between blastospores and germ tubes of Candida albicans, were further studied by comparing enzymatic digests of cell walls of both growth forms in radiolabeled organisms. Organisms were labeled either on the surface with 125 I, or metabolically with [ 35 S] methionine or [ 3 H] mannose. Three-surface-located components (as shown by antibody adsorption and elution experiments) were precipitated from Zymolase digests. All three components were mannoproteins as shown by their ability to bind Concanavalin A, and to be labeled in protein labeling procedures, and two of these (200,000 and 155,000 molecular weight) were germ tube specific, as shown by their ability to be precipitated by germ tube-specific antiserum. Monoclonal antibodies were prepared to C. albicans, using blastospores bearing germ tubes as immunogen

  20. Alternative Candida albicans lifestyles: growth on surfaces.

    Science.gov (United States)

    Kumamoto, Carol A; Vinces, Marcelo D

    2005-01-01

    Candida albicans, an opportunistic fungal pathogen, causes a wide variety of human diseases such as oral thrush and disseminated candidiasis. Many aspects of C. albicans physiology have been studied during liquid growth, but in its natural environment, the gastrointestinal tract of a mammalian host, the organism associates with surfaces. Growth on a surface triggers several behaviors, such as biofilm formation, invasion, and thigmotropism, that are important for infection. Recent discoveries have identified factors that regulate these behaviors and revealed the importance of these behaviors for pathogenesis.

  1. Neutrophil Interactions Stimulate Evasive Hyphal Branching by Aspergillus fumigatus.

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    Felix Ellett

    2017-01-01

    Full Text Available Invasive aspergillosis (IA, primarily caused by Aspergillus fumigatus, is an opportunistic fungal infection predominantly affecting immunocompromised and neutropenic patients that is difficult to treat and results in high mortality. Investigations of neutrophil-hypha interaction in vitro and in animal models of IA are limited by lack of temporal and spatial control over interactions. This study presents a new approach for studying neutrophil-hypha interaction at single cell resolution over time, which revealed an evasive fungal behavior triggered by interaction with neutrophils: Interacting hyphae performed de novo tip formation to generate new hyphal branches, allowing the fungi to avoid the interaction point and continue invasive growth. Induction of this mechanism was independent of neutrophil NADPH oxidase activity and neutrophil extracellular trap (NET formation, but could be phenocopied by iron chelation and mechanical or physiological stalling of hyphal tip extension. The consequence of branch induction upon interaction outcome depends on the number and activity of neutrophils available: In the presence of sufficient neutrophils branching makes hyphae more vulnerable to destruction, while in the presence of limited neutrophils the interaction increases the number of hyphal tips, potentially making the infection more aggressive. This has direct implications for infections in neutrophil-deficient patients and opens new avenues for treatments targeting fungal branching.

  2. Secreted Aspartic Protease Cleavage of Candida albicans Msb2 Activates Cek1 MAPK Signaling Affecting Biofilm Formation and Oropharyngeal Candidiasis

    Science.gov (United States)

    Chadha, Sonia; Tati, Swetha; Conti, Heather R.; Hube, Bernhard; Cullen, Paul J.; Edgerton, Mira

    2012-01-01

    Perception of external stimuli and generation of an appropriate response are crucial for host colonization by pathogens. In pathogenic fungi, mitogen activated protein kinase (MAPK) pathways regulate dimorphism, biofilm/mat formation, and virulence. Signaling mucins, characterized by a heavily glycosylated extracellular domain, a transmembrane domain, and a small cytoplasmic domain, are known to regulate various signaling pathways. In Candida albicans, the mucin Msb2 regulates the Cek1 MAPK pathway. We show here that Msb2 is localized to the yeast cell wall and is further enriched on hyphal surfaces. A msb2Δ/Δ strain formed normal hyphae but had biofilm defects. Cek1 (but not Mkc1) phosphorylation was absent in the msb2Δ/Δ mutant. The extracellular domain of Msb2 was shed in cells exposed to elevated temperature and carbon source limitation, concomitant with germination and Cek1 phosphorylation. Msb2 shedding occurred differentially in cells grown planktonically or on solid surfaces in the presence of cell wall and osmotic stressors. We further show that Msb2 shedding and Cek1 phosphorylation were inhibited by addition of Pepstatin A (PA), a selective inhibitor of aspartic proteases (Saps). Analysis of combinations of Sap protease mutants identified a sap8Δ/Δ mutant with reduced MAPK signaling along with defects in biofilm formation, thereby suggesting that Sap8 potentially serves as a major regulator of Msb2 processing. We further show that loss of either Msb2 (msb2Δ/Δ) or Sap8 (sap8Δ/Δ) resulted in higher C. albicans surface β-glucan exposure and msb2Δ/Δ showed attenuated virulence in a murine model of oral candidiasis. Thus, Sap-mediated proteolytic cleavage of Msb2 is required for activation of the Cek1 MAPK pathway in response to environmental cues including those that induce germination. Inhibition of Msb2 processing at the level of Saps may provide a means of attenuating MAPK signaling and reducing C. albicans virulence. PMID:23139737

  3. Simvastatin inhibits Candida albicans biofilm in vitro.

    Science.gov (United States)

    Liu, Geoffrey; Vellucci, Vincent F; Kyc, Stephanie; Hostetter, Margaret K

    2009-12-01

    By inhibiting the conversion of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) to mevalonate, statins impair cholesterol metabolism in humans. We reasoned that statins might similarly interfere with the biosynthesis of ergosterol, the major sterol of the yeast cell membrane. As assessed by spectrophotometric and microscopic analysis, significant inhibition of biofilm production was noted after 16-h incubation with 1, 2.5, and 5 muM simvastatin, concentrations that did not affect growth, adhesion, or hyphal formation by C. albicans in vitro. Higher concentrations (10, 20, and 25 muM simvastatin) inhibited biofilm by >90% but also impaired growth. Addition of exogenous ergosterol (90 muM) overcame the effects of 1 and 2.5 muM simvastatin, suggesting that at least one mechanism of inhibition is interference with ergosterol biosynthesis. Clinical isolates from blood, skin, and mucosal surfaces produced biofilms; biofilms from bloodstream isolates were similarly inhibited by simvastatin. In the absence of fungicidal activity, simvastatin's interruption of a critical step in an essential metabolic pathway, highly conserved from yeast to man, has unexpected effects on biofilm production by a eukaryotic pathogen.

  4. Candida albicans pathogenicity mechanisms.

    Science.gov (United States)

    Mayer, François L; Wilson, Duncan; Hube, Bernhard

    2013-02-15

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen.

  5. Candida albicans pathogenicity mechanisms

    Science.gov (United States)

    Mayer, François L.; Wilson, Duncan; Hube, Bernhard

    2013-01-01

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen. PMID:23302789

  6. Contribution of Candida albicans cell wall components to recognition by and escape from murine macrophages.

    Science.gov (United States)

    McKenzie, C G J; Koser, U; Lewis, L E; Bain, J M; Mora-Montes, H M; Barker, R N; Gow, N A R; Erwig, L P

    2010-04-01

    The pathogenicity of the opportunistic human fungal pathogen Candida albicans depends on its ability to escape destruction by the host immune system. Using mutant strains that are defective in cell surface glycosylation, cell wall protein synthesis, and yeast-hypha morphogenesis, we have investigated three important aspects of C. albicans innate immune interactions: phagocytosis by primary macrophages and macrophage cell lines, hyphal formation within macrophage phagosomes, and the ability to escape from and kill macrophages. We show that cell wall glycosylation is critically important for the recognition and ingestion of C. albicans by macrophages. Phagocytosis was significantly reduced for mutants deficient in phosphomannan biosynthesis (mmn4Delta, pmr1Delta, and mnt3 mnt5Delta), whereas O- and N-linked mannan defects (mnt1Delta mnt2Delta and mns1Delta) were associated with increased ingestion, compared to the parent wild-type strains and genetically complemented controls. In contrast, macrophage uptake of mutants deficient in cell wall proteins such as adhesins (ece1Delta, hwp1Delta, and als3Delta) and yeast-locked mutants (clb2Delta, hgc1Delta, cph1Delta, efg1Delta, and efg1Delta cph1Delta), was similar to that observed for wild-type C. albicans. Killing of macrophages was abrogated in hypha-deficient strains, significantly reduced in all glycosylation mutants, and comparable to wild type in cell wall protein mutants. The diminished ability of glycosylation mutants to kill macrophages was not a consequence of impaired hyphal formation within macrophage phagosomes. Therefore, cell wall composition and the ability to undergo yeast-hypha morphogenesis are critical determinants of the macrophage's ability to ingest and process C. albicans.

  7. Calcium homeostasis is required for contact-dependent helical and sinusoidal tip growth in Candida albicans hyphae.

    Science.gov (United States)

    Brand, Alexandra; Lee, Keunsook; Veses, Veronica; Gow, Neil A R

    2009-03-01

    Hyphae of the dimorphic fungus, Candida albicans, exhibit directional tip responses when grown in contact with surfaces. On hard surfaces or in liquid media, the trajectory of hyphal growth is typically linear, with tip re-orientation events limited to encounters with topographical features (thigmotropism). In contrast, when grown on semisolid surfaces, the tips of C. albicans hyphae grow in an oscillatory manner to form regular two-dimensional sinusoidal curves and three-dimensional helices. We show that, like thigmotropism, initiation of directional tip oscillation in C. albicans hyphae is severely attenuated when Ca2+ homeostasis is perturbed. Chelation of extracellular Ca2+ or deletion of the Ca2+ transporters that modulate cytosolic [Ca2+] (Mid1, Cch1 or Pmr1) did not affect hyphal length but curve formation was severely reduced in mid1Delta and cch1Delta and abolished in pmr1Delta. Sinusoidal hypha morphology was altered in the mid1Delta, chs3Delta and heterozygous pmr1Delta/PMR1 strains. Treatments that affect cell wall integrity, changes in surface mannosylation or the provision of additional carbon sources had significant but less pronounced effects on oscillatory growth. The induction of two- and three-dimensional sinusoidal growth in wild-type C. albicans hyphae is therefore the consequence of mechanisms that involve Ca2+ influx and signalling rather than gross changes in the cell wall architecture.

  8. The PHR Family: The Role of Extracellular Transglycosylases in Shaping Candida albicans Cells

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    Laura Popolo

    2017-10-01

    Full Text Available Candida albicans is an opportunistic microorganism that can become a pathogen causing mild superficial mycosis or more severe invasive infections that can be life-threatening for debilitated patients. In the etiology of invasive infections, key factors are the adaptability of C. albicans to the different niches of the human body and the transition from a yeast form to hypha. Hyphal morphology confers high adhesiveness to the host cells, as well as the ability to penetrate into organs. The cell wall plays a crucial role in the morphological changes C. albicans undergoes in response to specific environmental cues. Among the different categories of enzymes involved in the formation of the fungal cell wall, the GH72 family of transglycosylases plays an important assembly role. These enzymes cut and religate β-(1,3-glucan, the major determinant of cell shape. In C. albicans, the PHR family encodes GH72 enzymes, some of which work in specific environmental conditions. In this review, we will summarize the work from the initial discovery of PHR genes to the study of the pH-dependent expression of PHR1 and PHR2, from the characterization of the gene products to the recent findings concerning the stress response generated by the lack of GH72 activity in C. albicans hyphae.

  9. Investigation of touch-sensitive responses by hyphae of the human pathogenic fungus Candida albicans.

    Science.gov (United States)

    Gow, N A; Perera, T H; Sherwood-Higham, J; Gooday, G W; Gregory, D W; Marshall, D

    1994-01-01

    Candida albicans is a fungus that commonly infects the mucosal surface of humans. The hyphal growth form of this fungus may initiate the primary invasion of the host. Here we show that hyphae respond thigmotropically and morphologically to cues such as the presence of a surface, pores, grooves and ridges. Growth on some firm surfaces elicits a helical growth response. Hyphae follow grooves and ridges of inert substrates and penetrate pores of filtration membranes. Our in vitro experiments suggest that thigmotropism may enhance the ability of a hypha to invade epithelia of a host at sites of weakened integrity.

  10. Dynamics of biofilm formation and the interaction between Candida albicans and methicillin-susceptible (MSSA and -resistant Staphylococcus aureus (MRSA.

    Directory of Open Access Journals (Sweden)

    Chaiene Evelin Zago

    Full Text Available Polymicrobial biofilms are an understudied and a clinically relevant problem. This study evaluates the interaction between C. albicans, and methicillin- susceptible (MSSA and resistant (MRSA S. aureus growing in single- and dual-species biofilms. Single and dual species adhesion (90 min and biofilms (12, 24, and 48 h were evaluated by complementary methods: counting colony-forming units (CFU mL-1, XTT-reduction, and crystal violet staining (CV. The secretion of hydrolytic enzymes by the 48 h biofilms was also evaluated using fluorimetric kits. Scanning electron microscopy (SEM was used to assess biofilm structure. The results from quantification assays were compared using two-way ANOVAs with Tukey post-hoc tests, while data from enzymatic activities were analyzed by one-way Welch-ANOVA followed by Games-Howell post hoc test (α = 0.05. C. albicans, MSSA and MRSA were able to adhere and to form biofilm in both single or mixed cultures. In general, all microorganisms in both growth conditions showed a gradual increase in the number of cells and metabolic activity over time, reaching peak values between 12 h and 48 h (ρ<0.05. C. albicans single- and dual-biofilms had significantly higher total biomass values (ρ<0.05 than single biofilms of bacteria. Except for single MRSA biofilms, all microorganisms in both growth conditions secreted proteinase and phospholipase-C. SEM images revealed extensive adherence of bacteria to hyphal elements of C. albicans. C. albicans, MSSA, and MRSA can co-exist in biofilms without antagonism and in an apparent synergistic effect, with bacteria cells preferentially associated to C. albicans hyphal forms.

  11. Neutrophil-mediated protection of cultured human vascular endothelial cells from damage by growing Candida albicans hyphae

    International Nuclear Information System (INIS)

    Edwards, J.E. Jr.; Rotrosen, D.; Fontaine, J.W.; Haudenschild, C.C.; Diamond, R.D.

    1987-01-01

    Interactions were studied between human neutrophils and cultured human umbilical vein endothelial cells invaded by Candida albicans. In the absence of neutrophils, progressive Candida germination and hyphal growth extensively damaged endothelial cell monolayers over a period of 4 to 6 hours, as determined both by morphological changes and release of 51 Cr from radiolabeled endothelial cells. Monolayers were completely destroyed and replaced by hyphae after 18 hours of incubation. In contrast, when added 2 hours after the monolayers had been infected with Candida, neutrophils selectively migrated toward and attached to hyphae at points of hyphal penetration into individual endothelial cells (observed by time-lapse video-microscopy). Attached neutrophils spread over hyphal surfaces both within and beneath the endothelial cells; neutrophil recruitment to initial sites of leukocyte-Candida-endothelial cell interactions continued throughout the first 60 minutes of observation. Neutrophil spreading and stasis were observed only along Candida hyphae and at sites of Candida-endothelial cell interactions. These events resulted in 58.0% killing of Candida at 2 hours and subsequent clearance of Candida from endothelial cell monolayers, as determined by microcolony counts and morphological observation. On introduction of additional neutrophils to yield higher ratios of neutrophils to endothelial cells (10 neutrophils:1 endothelial cell), neutrophil migration toward hyphal elements continued. Despite retraction or displacement of occasional endothelial cells by invading Candida and neutrophils, most endothelial cells remained intact, viable, and motile as verified both by morphological observations and measurement of 51 Cr release from radiolabeled monolayers

  12. Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.

    Directory of Open Access Journals (Sweden)

    Read Pukkila-Worley

    2011-06-01

    Full Text Available Candida albicans yeast cells are found in the intestine of most humans, yet this opportunist can invade host tissues and cause life-threatening infections in susceptible individuals. To better understand the host factors that underlie susceptibility to candidiasis, we developed a new model to study antifungal innate immunity. We demonstrate that the yeast form of C. albicans establishes an intestinal infection in Caenorhabditis elegans, whereas heat-killed yeast are avirulent. Genome-wide, transcription-profiling analysis of C. elegans infected with C. albicans yeast showed that exposure to C. albicans stimulated a rapid host response involving 313 genes (124 upregulated and 189 downregulated, ~1.6% of the genome many of which encode antimicrobial, secreted or detoxification proteins. Interestingly, the host genes affected by C. albicans exposure overlapped only to a small extent with the distinct transcriptional responses to the pathogenic bacteria Pseudomonas aeruginosa or Staphylococcus aureus, indicating that there is a high degree of immune specificity toward different bacterial species and C. albicans. Furthermore, genes induced by P. aeruginosa and S. aureus were strongly over-represented among the genes downregulated during C. albicans infection, suggesting that in response to fungal pathogens, nematodes selectively repress the transcription of antibacterial immune effectors. A similar phenomenon is well known in the plant immune response, but has not been described previously in metazoans. Finally, 56% of the genes induced by live C. albicans were also upregulated by heat-killed yeast. These data suggest that a large part of the transcriptional response to C. albicans is mediated through "pattern recognition," an ancient immune surveillance mechanism able to detect conserved microbial molecules (so-called pathogen-associated molecular patterns or PAMPs. This study provides new information on the evolution and regulation of the innate

  13. Gene expression profile of THP-1 cells treated with heat-killed Candida albicans.

    Science.gov (United States)

    Hu, Zhi-De; Wei, Ting-Ting; Tang, Qing-Qin; Ma, Ning; Wang, Li-Li; Qin, Bao-Dong; Yin, Jian-Rong; Zhou, Lin; Zhong, Ren-Qian

    2016-05-01

    Mechanisms under immune response against Candida albicans (C. albicans) remain largely unknown. To better understand the mechanisms of innate immune response against C. albicans, we analyzed the gene expression profile of THP-1 cells stimulated with heat-killed C. albicans. THP-1 cells were stimulated with heat-killed C. albicans for 9 hours at a ratio of 1:1, and gene expression profile of the cells was analyzed using Whole Human Genome Oligo Microarray. Differentially expressed genes were defined as change folds more than 2 and with statistical significance. Gene ontology (GO) and pathway analysis were used to systematically identify biological connections of differentially expressed genes, as well as the pathways associated with the immune response against C. albicans. A total of 355 genes were up-regulated and 715 genes were down-regulated significantly. The up-regulated genes were particularly involved in biological process of RNA processing and pathway of the spliceosome. In case of down-regulated genes, the particularly involved immune-related pathways were G-protein coupled receptor signaling pathway, calcium signaling pathway, MAPK signaling pathway and Ras pathway. We depict the gene expression profile of heat-killed C. albicans stimulated THP-1 cells, and identify the major pathways involved in immune response against C. albicans. These pathways are potential candidate targets for developing anti-C. albicans agent.

  14. Budding off: bringing functional genomics to Candida albicans

    Science.gov (United States)

    Anderson, Matthew Z.

    2016-01-01

    Candida species are the most prevalent human fungal pathogens, with Candida albicans being the most clinically relevant species. Candida albicans resides as a commensal of the human gastrointestinal tract but is a frequent cause of opportunistic mucosal and systemic infections. Investigation of C. albicans virulence has traditionally relied on candidate gene approaches, but recent advances in functional genomics have now facilitated global, unbiased studies of gene function. Such studies include comparative genomics (both between and within Candida species), analysis of total RNA expression, and regulation and delineation of protein–DNA interactions. Additionally, large collections of mutant strains have begun to aid systematic screening of clinically relevant phenotypes. Here, we will highlight the development of functional genomics in C. albicans and discuss the use of these approaches to addressing both commensalism and pathogenesis in this species. PMID:26424829

  15. Hyphal transport by a vesicular-arbuscular mycorrhizal fungus of N applied to the soil as ammonium or nitrate

    DEFF Research Database (Denmark)

    Johansen, A.; Jakobsen, I.; Jensen, E.S.

    1993-01-01

    with a hyphal compartment separated from the root compartment by a fine nylon mesh. Mineral N was then applied to the hyphal compartment as (NH4+)-N-15 or (NO3-)-N-15 at 5 cm distance from the root compartment. Soil samples were taken from the hyphal compartment at 1, 3 and 5 cm distance from the root...

  16. Development of a phosphorylated Momordica charantia protein system for inhibiting susceptible dose-dependent C. albicans to available antimycotics: An allosteric regulation of protein.

    Science.gov (United States)

    Qiao, Yuanbiao; Song, Li; Zhu, Chenchen; Wang, Qian; Guo, Tianyan; Yan, Yanhua; Li, Qingshan

    2017-11-15

    A regulatory Momordica charantia protein system was constructed allosterically by in vitro protein phosphorylation, in an attempt to evaluate antimycological pluripotency against dose-dependent susceptibilities in C. albicans. Fungal strain lineages susceptible to ketoconazole, econazole, miconazole, 5-flucytosine, nystatin and amphotericin B were prepared in laboratory, followed by identification via antifungal susceptibility testing. Protein phosphorylation was carried out in reactions with 5'-adenylic, guanidylic, cytidylic and uridylic acids and cyclic adenosine triphosphate, through catalysis of cyclin-dependent kinase 1, protein kinase A and protein kinase C respectively. Biochemical analysis of enzymatic reactions indicated the apparent Michaelis-Menten constants and maximal velocity values of 16.57-91.97mM and 55.56-208.33μM·min -1 , together with an approximate 1:1 reactant stoichiometric ratio. Three major protein phosphorylation sites were theoretically predicted at Thr255, Thr102 and Thr24 by a KinasePhos tool. Additionally, circular dichroism spectroscopy demonstrated that upon phosphorylation, protein folding structures were decreased in random coil, β6-sheet and α1-helix partial regions. McFarland equivalence standard testing yielded the concentration-dependent inhibition patterns, while fungus was grown in Sabouraud's dextrose agar. The minimal inhibitory concentrations of 0.16-0.51μM (at 50% response) were obtained for free protein and phosphorylated counterparts. With respect to the 3-cycling susceptibility testing regimen, individuals of total protein forms were administrated in-turn at 0.14μM/cycle. Relative inhibition ratios were retained to 66.13-81.04% of initial ones regarding the ketoconazole-susceptible C. albicans growth. An inhibitory protein system, with an advantage of decreasing antifungal susceptibilities to diverse antimycotics, was proposed because of regulatory pluripotency whereas little contribution to susceptibility in

  17. [Virulence factors of Candida albicans].

    Science.gov (United States)

    Staniszewska, Monika; Bondaryk, Małgorzata; Piłat, Joanna; Siennicka, Katarzyna; Magda, Urszula; Kurzatkowski, Wiesław

    2012-01-01

    Candida albicans is the most common etiological factor of opportunistic human fungal infections. In this review, we focus on the major virulence factors that mediate the pathogenesis of C. albicans. Among these virulence factors, secreted aspartyl proteases, adherence, pleomorphism are the most important features of C. albicans infections. Ability to exist as different pleomorphic forms is defined as pleomorphism. A number of quorum sensing (QS) molecules have been described which affect morphogenesis process in C. albicans. Furthermore, the morphological transition of C. albicans in response to changing environmental conditions represent a means by which the strain adapts to different biological niches. Furthermore, every morphotype has own virulence profile and each pleomorphic form provide critical functions required for pathogenesis. Candida albicans is a producer of extracellular hydrolytic enzymes. Among them lipases, phospholipases and secreted aspartyl proteinases (Sap) are most significant in virulence. Sap proteins contribute to pathogenesis by digestion of host cell membranes and molecules of the host immune system to avoid antimicrobial attack by the host. One of the key features in the development of candidiasis is adhesion ofC. albicans to buccal and vaginal epithelial cells. The adhesion to host cells represents the first step in the internalization process which involves adhesins. Knowledge of the role of the various C. albicans' virulence factors during in vivo infections is still incomplete, therefore further studies including quantification of genes expression and histopathological examination of tissues damage are required to fully understand pathogenesis of this opportunistic pathogen.

  18. Innate immunity to Candida albicans

    Directory of Open Access Journals (Sweden)

    Yusuke Kiyoura

    2015-08-01

    Full Text Available Candida albicans is not a pathogen in healthy individuals, but can cause severe systemic candidiasis in immunocompromised patients. C. albicans has various virulence factors and activates the innate immune system. Specifically, C. albicans induces proinflammatory cytokine production in various cell types via many receptors, such as Toll-like receptors (TLRs and C-type lectin receptors (CLRs. This microorganism also promotes phagocytosis via CLRs on macrophages. In a previous study, we found that C. albicans induces the production of galectin-3, which is a known CLR that kills C. albicans. This review indicates that the use of mouthwash containing an antimicrobial peptide or protein might be a useful new oral care method for the prevention of oral candidiasis.

  19. The transcription factor Ste12 mediates the regulatory role of the Tmk1 MAP kinase in mycoparasitism and vegetative hyphal fusion in the filamentous fungus Trichoderma atroviride.

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    Sabine Gruber

    Full Text Available Mycoparasitic species of the fungal genus Trichoderma are potent antagonists able to combat plant pathogenic fungi by direct parasitism. An essential step in this mycoparasitic fungus-fungus interaction is the detection of the fungal host followed by activation of molecular weapons in the mycoparasite by host-derived signals. The Trichoderma atroviride MAP kinase Tmk1, a homolog of yeast Fus3/Kss1, plays an essential role in regulating the mycoparasitic host attack, aerial hyphae formation and conidiation. However, the transcription factors acting downstream of Tmk1 are hitherto unknown. Here we analyzed the functions of the T. atroviride Ste12 transcription factor whose orthologue in yeast is targeted by the Fus3 and Kss1 MAP kinases. Deletion of the ste12 gene in T. atroviride not only resulted in reduced mycoparasitic overgrowth and lysis of host fungi but also led to loss of hyphal avoidance in the colony periphery and a severe reduction in conidial anastomosis tube formation and vegetative hyphal fusion events. The transcription of several orthologues of Neurospora crassa hyphal fusion genes was reduced upon ste12 deletion; however, the Δste12 mutant showed enhanced expression of mycoparasitism-relevant chitinolytic and proteolytic enzymes and of the cell wall integrity MAP kinase Tmk2. Based on the comparative analyses of Δste12 and Δtmk1 mutants, an essential role of the Ste12 transcriptional regulator in mediating outcomes of the Tmk1 MAPK pathway such as regulation of the mycoparasitic activity, hyphal fusion and carbon source-dependent vegetative growth is suggested. Aerial hyphae formation and conidiation, in contrast, were found to be independent of Ste12.

  20. Distinct roles of two ceramide synthases, CaLag1p and CaLac1p, in the morphogenesis of Candida albicans

    DEFF Research Database (Denmark)

    Cheon, Seon Ah; Bal, Jyotiranjan; Song, Yunkyoung

    2012-01-01

    Lag1p and Lac1p catalyse ceramide synthesis in Saccharomyces cerevisiae. This study shows that Lag1 family proteins are generally required for polarized growth in hemiascomycetous yeast. However, in contrast to S. cerevisiae where these proteins are functionally redundant, C. albicans Lag1p (CaLag1......p) and Lac1p (CaLac1p) are functionally distinct. Lack of CaLag1p, but not CaLac1p, caused severe defects in the growth and hyphal morphogenesis of C. albicans. Deletion of CaLAG1 decreased expression of the hypha-specific HWP1 and ECE1 genes. Moreover, overexpression of CaLAG1 induced pseudohyphal....... albicans....

  1. Identification of genes differentially expressed in hyphae of Candida albicans Identificação de gases em hifa de Candida albicans

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    Analy Salles de Azevedo Melo

    2003-11-01

    Full Text Available The ability to switch from yeast to hyphal forms is essential for Candida albicans virulence. This morphological switch involves the expression of hyphal-specific genes under the control of transcriptional factors. To contribute to the discovery of hyphal-specific genes, we used a differential screening method where clones of a genomic DNA library were hybridized with yeast and hyphal cDNA probes. Two clones with increased expression in hyphae were selected for study. Sequencing these clones, we found that they encoded two important metabolic genes, CaHXT7 (high-affinity hexose transporter and CaYLL34 (member of the AAA ATPase family. CaHXT7 and CaYLL34 ORFs were completely determined. Analyses of the putative proteins show that: (1 CaHxt7p has one hexose transporter domain and (2 CaYll34p has two AAA ATPase domains. These results show, for the first time, increased expression of metabolic genes in C. albicans hyphae. Also, because the proteins encoded by CaHXT7 and CaYLL34 may be necessary for the switching to hyphae, they could be new targets for antifungal drugs.A transição morfológica de levedura para hifa é essencial para a virulência de Candida albicans. Esta transição envolve a expressão de genes hifa-específicos que estão sob o controle de fatores transcricionais. Para descobrir genes hifa-específicos utilizamos um método de triagem diferencial, onde clones de biblioteca de DNA genômico foram hibridizados com sondas de cDNA de levedura e hifa. Dois clones com aumento de expressão em hifa foram selecionados. O sequenciamento dos insertos destes clones permitiu a identificação de dois genes metabólicos importantes: CaHXT7 (high-affinity hexose transporter e CaYLL34 (da família AAA ATPase. As ORFs completas destes genes foram caracterizadas e a análise das proteínas hipotéticas revelou que: (1 CaHxt7p tem um domínio de transportador de hexose e (2 CaYll34 tem dois domínios AAA ATPase. Este é o primeiro estudo que

  2. Synergic effect of combination of glycyrol and fluconazole against experimental cutaneous candidiasis due to Candida albicans.

    Science.gov (United States)

    Rhew, Zheong-Imm; Han, Yongmoon

    2016-10-01

    In this study, we investigated the anti-fungal activity of glycyrol, a coumarine isolated from licorice (Glycyrrhizae Radix), in a murine model of cutaneous candidiasis caused by Candida albicans. Compared to the infected sites, located on the mice's back, of the untreated control mice, the infected sites treated with glycyrol had reduced CFU (colony forming unit) values up to 60 and 85.5 % at 20 and 40 μg/mouse of glycyrol, respectively (P < 0.01). The antifungal activity of glycyrol was synergistically increased when glycyrol (10 μg/mouse) was combined with fluconazole (10 μg/mouse), demonstrating that the combination therapy is approximately 4 times more effective than fluconazole alone at 20 μg/mouse (P < 0.01). Additionally, the combination activity was 1.65 times greater than the antifungal activity of fluconazole alone at 40 μg/mouse (P < 0.05). In seeking glycyrol's antifungal mechanism, we determined that glycyrol inhibited hyphal induction and cell wall adherence of C. albicans. Thus, it is very likely that, by damaging the cell wall, glycyrol helps fluconazole invade C. albicans more readily and attack fluconazole's target in the fungus membrane. In summary, our data indicate that glycyrol may contribute to the development of a novel agent that possesses antifungal activity against cutaneous candidiasis.

  3. Treatment with some anti-inflammatory drugs reduces germ tube formation in Candida albicans strains

    Directory of Open Access Journals (Sweden)

    Elena Rusu

    2014-12-01

    Full Text Available Candida albicans is an opportunistic dimorphic fungus that inhabits various host mucosal sites. It can cause both superficial and serious systemic disease. Conversion from the yeast to the hyphal form has been associated with increased virulence and mucosal invasiveness. The aim of this study was to investigate the effect of sodium diclofenac and aspirin on germs tube formation of different Candida albicans strains. Prostaglandins may play an important role in fungal colonization. Nonsteroidal anti-inflammatory drugs are inhibitors of the cyclooxygenase isoenzymes. These drugs specifically block the biosynthesis of mammalian prostaglandins by inhibiting one or both of cyclooxygenase isoenzymes. In tests for germ tube formation sodium diclofenac reduced the filamentation to the 12.5%- 5.1%. In the presence of aspirin the filamentation was reduced up to 85-45% depending on the tested strain. Our results suggest that cyclooxygenase-depending synthesis of fungal prostaglandins is important for morphogenesis and fungal virulence. Inhibitors of cyclooxygenase isoensymes (aspirin and diclofenac are effective in decreasing germ tube formation of Candida albicans.

  4. The effect of Streptococcus mutans and Candida glabrata on Candida albicans biofilms formed on different surfaces.

    Science.gov (United States)

    Pereira-Cenci, Tatiana; Deng, Dong Mei; Kraneveld, Eefje Anne; Manders, Erik Martinus Marie; Del Bel Cury, Altair Antoninha; Ten Cate, Jacob Martien; Crielaard, Wim

    2008-08-01

    Although Candida containing biofilms contribute to the development of oral candidosis, the characteristics of multi-species Candida biofilms and how oral bacteria modulate these biofilms is poorly understood. The aim of this study was to investigate interactions between Candida albicans and either Candida glabrata or Streptococcus mutans in biofilms grown on various surfaces, with or without saliva. Hydroxyapatite (HA), polymethylmetacrylate (PMMA) and soft denture liner (SL) discs were used as substratum. Counts of viable micro-organisms in the accumulating biofilm layer were determined and converted to colony forming units per unit surface area. Confocal laser scanning microscopy was used to characterize biofilms and to quantitate the number of hyphae in each condition tested. Viable counts of C. albicans and C. glabrata per mm(2) decreased in the order HA>PMMA>SL (p<0.05). Biofilms grown on saliva-coated specimens harboured fewer C. glabrata than uncoated specimens (p<0.05). Glucose and the presence of S. mutans suppressed C. albicans hyphal formation. Dual Candida species biofilms did not show competitive interaction between the two species. We conclude that Candida biofilms are significantly affected by saliva, substratum type and by the presence of other micro-organisms.

  5. Oxidative Stress Responses in the Human Fungal Pathogen, Candida albicans

    Science.gov (United States)

    da Silva Dantas, Alessandra; Day, Alison; Ikeh, Mélanie; Kos, Iaroslava; Achan, Beatrice; Quinn, Janet

    2015-01-01

    Candida albicans is a major fungal pathogen of humans, causing approximately 400,000 life-threatening systemic infections world-wide each year in severely immunocompromised patients. An important fungicidal mechanism employed by innate immune cells involves the generation of toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. Consequently, there is much interest in the strategies employed by C. albicans to evade the oxidative killing by macrophages and neutrophils. Our understanding of how C. albicans senses and responds to ROS has significantly increased in recent years. Key findings include the observations that hydrogen peroxide triggers the filamentation of this polymorphic fungus and that a superoxide dismutase enzyme with a novel mode of action is expressed at the cell surface of C. albicans. Furthermore, recent studies have indicated that combinations of the chemical stresses generated by phagocytes can actively prevent C. albicans oxidative stress responses through a mechanism termed the stress pathway interference. In this review, we present an up-date of our current understanding of the role and regulation of oxidative stress responses in this important human fungal pathogen. PMID:25723552

  6. Vegetative hyphal fusion and subsequent nuclear behavior in Epichloë grass endophytes.

    Science.gov (United States)

    Shoji, Jun-Ya; Charlton, Nikki D; Yi, Mihwa; Young, Carolyn A; Craven, Kelly D

    2015-01-01

    Epichloë species (including the former genus Neotyphodium) are fungal symbionts of many agronomically important forage grasses, and provide their grass hosts with protection from a wide range of biotic and abiotic stresses. Epichloë species include many interspecific hybrids with allodiploid-like genomes, which may provide the potential for combined traits or recombination to generate new traits. Though circumstantial evidence suggests that such interspecific hybrids might have arisen from nuclear fusion events following vegetative hyphal fusion between different Epichloë strains, this hypothesis has not been addressed empirically. Here, we investigated vegetative hyphal fusion and subsequent nuclear behavior in Epichloë species. A majority of Epichloë strains, especially those having a sexual stage, underwent self vegetative hyphal fusion. Vegetative fusion also occurred between two hyphae from different Epichloë strains. Though Epichloë spp. are uninucleate fungi, hyphal fusion resulted in two nuclei stably sharing the same cytoplasm, which might ultimately lead to nuclear fusion. In addition, protoplast fusion experiments gave rise to uninucleate putative hybrids, which apparently had two markers, one from each parent within the same nucleus. These results are consistent with the notion that interspecific hybrids arise from vegetative hyphal fusion. However, we also discuss additional factors, such as post-hybridization selection, that may be important to explain the recognized prevalence of hybrids in Epichloë species.

  7. Vegetative hyphal fusion and subsequent nuclear behavior in Epichloë grass endophytes.

    Directory of Open Access Journals (Sweden)

    Jun-Ya Shoji

    Full Text Available Epichloë species (including the former genus Neotyphodium are fungal symbionts of many agronomically important forage grasses, and provide their grass hosts with protection from a wide range of biotic and abiotic stresses. Epichloë species include many interspecific hybrids with allodiploid-like genomes, which may provide the potential for combined traits or recombination to generate new traits. Though circumstantial evidence suggests that such interspecific hybrids might have arisen from nuclear fusion events following vegetative hyphal fusion between different Epichloë strains, this hypothesis has not been addressed empirically. Here, we investigated vegetative hyphal fusion and subsequent nuclear behavior in Epichloë species. A majority of Epichloë strains, especially those having a sexual stage, underwent self vegetative hyphal fusion. Vegetative fusion also occurred between two hyphae from different Epichloë strains. Though Epichloë spp. are uninucleate fungi, hyphal fusion resulted in two nuclei stably sharing the same cytoplasm, which might ultimately lead to nuclear fusion. In addition, protoplast fusion experiments gave rise to uninucleate putative hybrids, which apparently had two markers, one from each parent within the same nucleus. These results are consistent with the notion that interspecific hybrids arise from vegetative hyphal fusion. However, we also discuss additional factors, such as post-hybridization selection, that may be important to explain the recognized prevalence of hybrids in Epichloë species.

  8. The Natural Product Citral Can Cause Significant Damage to the Hyphal Cell Walls of Magnaporthe grisea

    Directory of Open Access Journals (Sweden)

    Rong-Yu Li

    2014-07-01

    Full Text Available In order to find a natural alternative to the synthetic fungicides currently used against the devastating rice blast fungus, Magnaporthe grisea, this study explored the antifungal potential of citral and its mechanism of action. It was found that citral not only inhibited hyphal growth of M. grisea, but also caused a series of marked hyphal morphological and structural alterations. Specifically, citral was tested for antifungal activity against M. grisea in vitro and was found to significantly inhibit colony development and mycelial growth with IC50 and IC90 values of 40.71 and 203.75 μg/mL, respectively. Furthermore, citral reduced spore germination and germ tube length in a concentration-dependent manner. Following exposure to citral, the hyphal cell surface became wrinkled with folds and cell breakage that were observed under scanning electron microscopy (SEM. There was damage to hyphal cell walls and membrane structures, loss of villous-like material outside of the cell wall, thinning of the cell wall, and discontinuities formed in the cell membrane following treatment based on transmission electron microscopy (TEM. This increase in chitinase activity both supports the morphological changes seen in the hyphae, and also suggests a mechanism of action. In conclusion, citral has strong antifungal properties, and treatment with this compound is capable of causing significant damage to the hyphal cell walls of M. grisea.

  9. Effect of a Lactobacillus Salivarius Probiotic on a Double-Species Streptococcus Mutans and Candida Albicans Caries Biofilm

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    Wirginia Krzyściak

    2017-11-01

    Full Text Available The aim of the study was to evaluate the anti-cariogenic effects of Lactobacillus salivarius by reducing pathogenic species and biofilm mass in a double-species biofilm model. Coexistence of S. mutans with C. albicans can cause dental caries progression or recurrence of the disease in the future. Fifty-nine children with diagnosed early childhood caries (ECC were recruited onto the study. The condition of the children’s dentition was defined according to the World Health Organization guidelines. The participants were divided into children with initial enamel demineralization and children showing dentin damage. The study was performed on the S. mutans and C. albicans clinical strains, isolated from dental plaque of patients with ECC. The effect of a probiotic containing Lactobacillus salivarius on the ability of S. mutans and C. albicans to produce a double-species biofilm was investigated in an in vitro model. The biomass of the formed/non-degraded biofilm was analyzed on the basis of its crystal violet staining. The number of colonies of S. mutans and C. albicans (CFU/mL, colony forming units/mL forming the biofilm was determined. Microorganism morphology in the biofilm was evaluated using a scanning electron microscope (SEM. In vitro analysis demonstrated that the presence of S. mutans increased the number of C. albicans colonies (CFU/mL; the double-species biofilm mass and hyphal forms produced in it by the yeast. L. salivarius inhibited the cariogenic biofilm formation of C. albicans and S. mutans. Under the influence of the probiotic; the biofilm mass and the number of S. mutans; C. albicans and S. mutans with C. albicans colonies in the biofilm was decreased. Moreover; it can be noted that after the addition of the probiotic; fungi did not form hyphae or germ tubes of pathogenic potential. These results suggest that L. salivarius can secrete intermediates capable of inhibiting the formation of cariogenic S. mutans and C. albicans biofilm

  10. Ribosomal RNA processing in Candida albicans.

    Science.gov (United States)

    Pendrak, Michael L; Roberts, David D

    2011-12-01

    Ribosome assembly begins with conversion of a polycistronic precursor into 18S, 5.8S, and 25S rRNAs. In the ascomycete fungus Candida albicans, rRNA transcription starts 604 nt upstream of the 18S rRNA junction (site A1). One major internal processing site in the 5' external transcribed spacer (A0) occurs 108 nt from site A1. The A0-A1 fragment persists as a stable species during log phase growth and can be used to assess proliferation rates. Separation of the small and large subunit pre-rRNAs occurs at sites A2 and A3 in internal transcribed spacer-1 Saccharomyces cerevisiae pre-rRNA. However, the 5' end of the 5.8S rRNA is represented by only a 5.8S (S) form, and a 7S rRNA precursor of the 5.8S rRNA extends into internal transcribed spacer 1 to site A2, which differs from S. cerevisiae. External transcribed spacer 1 and internal transcribed spacers 1 and 2 show remarkable structural similarity with S. cerevisiae despite low sequence identity. Maturation of C. albicans rRNA resembles other eukaryotes in that processing can occur cotranscriptionally or post-transcriptionally. During rapid proliferation, U3 snoRNA-dependent processing occurs before large and small subunit rRNA separation, consistent with cotranscriptional processing. As cells pass the diauxic transition, the 18S pre-rRNA accumulates into stationary phase as a 23S species, possessing an intact 5' external transcribed spacer extending to site A3. Nutrient addition to starved cells results in the disappearance of the 23S rRNA, indicating a potential role in normal physiology. Therefore, C. albicans reveals new mechanisms that regulate post- versus cotranscriptional rRNA processing.

  11. Analysis of single hyphal growth and fragmentation in submerged cultures using a population model

    DEFF Research Database (Denmark)

    Krabben, Preben; Nielsen, Søren; Michelsen, Michael Locht

    1997-01-01

    Descriptions of population dynamics in submerged cultures are important when studying the mechanisms of growth and fragmentation of filamentous microorganisms. Population models are traditionally formulated as population balance equations. Population models of filamentous morphology are difficult...... to solve because of random fragmentation, which introduces an integral term into the population balance equations. Balances for the systemic properties, e.g. concentration of hyphal elements, substrate concentration, average total hyphal length, and average number of growing tips, are set up. Based...... on these balances one can solve the inverse problem, i.e. determination of kinetic parameters directly from measurements of the hyphal morphology. Both a Monte Carlo method and a discretization method have been used to calculate the steady-state population distribution. The two methods are compared and the Monte...

  12. Effects of Aeration of Sawdust Cultivation Bags on Hyphal Growth of Lentinula edodes.

    Science.gov (United States)

    Lee, Hwa-Yong; Ham, Eun-Ju; Yoo, Young-Jin; Kim, Eui-Sung; Shim, Kyu-Kwang; Kim, Myung-Kon; Koo, Chang-Duck

    2012-09-01

    The effects of aeration through lid filters on the hyphal growth of Lentinula edodes (oak mushroom) in sawdust cultivation bags were investigated. The aeration treatment levels were traditional 27 mm hole cotton plugs, cotton balls and combinations of seven hole sizes × two hole positions (up and under) in the lids covering plastic bags containing 1.4 kg sawdust medium at 63% moisture that had been autoclaved for one hour and inoculated with sawdust spawn of L. edodes strain 921. Aeration treatment effects were measured based on the CO(2) concentration at the 15th wk, as well as the hyphal growth rate and degree of weight loss of bags every 14 days for 15 wk. In bags with traditional cotton plugs, the CO(2) concentration was 3.8 ± 1.3%, daily mean hyphal growth was 2.3 ± 0.6 mm and daily mean weight loss was 0.84 ± 0.26 g. In the bags with 15 mm diameter holes, the CO(2) concentration was 6.0 ± 1.6%, daily hyphal growth was 2.8 ± 0.2 mm and daily weight loss was 0.86 ± 0.4 g. The bags with 15 mm holes had a higher CO(2) concentration and lower water loss than bags with other hole sizes, but the hyphal growth was not significantly different from that of other bags. The weight loss of bags increased proportionally relative to the lid hole sizes. Taken together, these results indicate that traditional cotton plugs are economically efficient, but 15 mm hole lids are the most efficient at maintaining hyphal growth and controlling water loss while allowing CO(2) emissions.

  13. Contact sensing in Candida albicans: a possible aid to epithelial penetration.

    Science.gov (United States)

    Sherwood, J; Gow, N A; Gooday, G W; Gregory, D W; Marshall, D

    1992-01-01

    Hyphal development in the dimorphic pathogenic fungus Candida albicans is thought to facilitate the primary invasion of surface epithelia during superficial infections. When mycelia were grown on Nuclepore membrane filters that were placed over serum-containing agar, the hyphae grew over the membrane surface and through the pores thereby crossing to the other side of the membrane. Hyphae that did not contact the lip of a pore did not enter it. The response was likely to be due to contact guidance (thigmotropism) and not chemotropism towards the nutrients since hyphae growing on the underside of the membrane also entered the pores then grew away from the underlying nutrient agar. The response therefore seems to be due to sensation of the substrate topography, and tropic movement in relation to changes in contour. This behaviour may enable the hyphae to penetrate epithelia at microscopic wound sites, membrane invaginations and other foci where the integrity of the epithelium is weak.

  14. Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2.

    Science.gov (United States)

    Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang; Zhao, Ming-Wen

    2016-07-15

    Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum Our data showed that HS induced a significant increase in cytosolic Ca(2+) concentration. Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research offers a new

  15. Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2+

    Science.gov (United States)

    Zhang, Xue; Ren, Ang; Li, Meng-Jiao; Cao, Peng-Fei; Chen, Tian-Xi; Zhang, Guang; Shi, Liang; Jiang, Ai-Liang

    2016-01-01

    ABSTRACT Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum. Our data showed that HS induced a significant increase in cytosolic Ca2+ concentration. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. IMPORTANCE Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum. Further evidence showed that Ca2+ might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca2+ participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research

  16. Change in hyphal morphology of Aspergillus Oryzae during fed-batch cultivation

    DEFF Research Database (Denmark)

    Haack, Martin Brian; Olsson, Lisbeth; Hansen, K

    2006-01-01

    the batch phase from 2.8-2.9 up to 4.0-4.4 mu m. The diameter of the hyphal elements remained constant, around 4 mu m, after the feed was started. However, the diameter of the immediate hyphal tip, where the enzyme secretion is thought to take place, increased dramatically with up to a factor 2.5 during......Industrial enzymes are often produced by filamentous fungi in fed-batch cultivations. During cultivation, the different morphological forms displayed by the fungi have an impact on the overall production. The morphology of a recombinant lipase producing Aspergillus oryzae strain was investigated...

  17. Factors supporting cysteine tolerance and sulfite production in Candida albicans.

    Science.gov (United States)

    Hennicke, Florian; Grumbt, Maria; Lermann, Ulrich; Ueberschaar, Nico; Palige, Katja; Böttcher, Bettina; Jacobsen, Ilse D; Staib, Claudia; Morschhäuser, Joachim; Monod, Michel; Hube, Bernhard; Hertweck, Christian; Staib, Peter

    2013-04-01

    The amino acid cysteine has long been known to be toxic at elevated levels for bacteria, fungi, and humans. However, mechanisms of cysteine tolerance in microbes remain largely obscure. Here we show that the human pathogenic yeast Candida albicans excretes sulfite when confronted with increasing cysteine concentrations. Mutant construction and phenotypic analysis revealed that sulfite formation from cysteine in C. albicans relies on cysteine dioxygenase Cdg1, an enzyme with similar functions in humans. Environmental cysteine induced not only the expression of the CDG1 gene in C. albicans, but also the expression of SSU1, encoding a putative sulfite efflux pump. Accordingly, the deletion of SSU1 resulted in enhanced sensitivity of the fungal cells to both cysteine and sulfite. To study the regulation of sulfite/cysteine tolerance in more detail, we screened a C. albicans library of transcription factor mutants in the presence of sulfite. This approach and subsequent independent mutant analysis identified the zinc cluster transcription factor Zcf2 to govern sulfite/cysteine tolerance, as well as cysteine-inducible SSU1 and CDG1 gene expression. cdg1Δ and ssu1Δ mutants displayed reduced hypha formation in the presence of cysteine, indicating a possible role of the newly proposed mechanisms of cysteine tolerance and sulfite secretion in the pathogenicity of C. albicans. Moreover, cdg1Δ mutants induced delayed mortality in a mouse model of disseminated infection. Since sulfite is toxic and a potent reducing agent, its production by C. albicans suggests diverse roles during host adaptation and pathogenicity.

  18. Novel Aggregation Properties of Candida albicans Secreted Aspartyl Proteinase Sap6 Mediate Virulence in Oral Candidiasis.

    Science.gov (United States)

    Kumar, Rohitashw; Saraswat, Darpan; Tati, Swetha; Edgerton, Mira

    2015-07-01

    Candida albicans, a commensal fungus of the oral microbiome, causes oral candidiasis in humans with localized or systemic immune deficiencies. Secreted aspartic proteinases (Saps) are a family of 10 related proteases and are virulence factors due to their proteolytic activity, as well as their roles in adherence and colonization of host tissues. We found that mice infected sublingually with C. albicans cells overexpressing Sap6 (SAP6 OE and a Δsap8 strain) had thicker fungal plaques and more severe oral infection, while infection with the Δsap6 strain was attenuated. These hypervirulent strains had highly aggregative colony structure in vitro and higher secreted proteinase activity; however, the levels of proteinase activity of C. albicans Saps did not uniformly match their abilities to damage cultured oral epithelial cells (SCC-15 cells). Hyphal induction in cells overexpressing Sap6 (SAP6 OE and Δsap8 cells) resulted in formation of large cell-cell aggregates. These aggregates could be produced in germinated wild-type cells by addition of native or heat-inactivated Sap6. Sap6 bound only to germinated cells and increased C. albicans adhesion to oral epithelial cells. The adhesion properties of Sap6 were lost upon deletion of its integrin-binding motif (RGD) and could be inhibited by addition of RGD peptide or anti-integrin antibodies. Thus, Sap6 (but not Sap5) has an alternative novel function in cell-cell aggregation, independent of its proteinase activity, to promote infection and virulence in oral candidiasis.

  19. Role of extracellular polymeric substances in polymicrobial biofilm infections of Staphylococcus epidermidis and Candida albicans modelled in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Holt, Jillian E; Houston, Asia; Adams, Clare; Edwards, Sarah; Kjellerup, Birthe V

    2017-07-31

    Biofilms are formed by communities of microorganisms living in a self-produced extracellular polymeric matrix attached to a surface. When living in a biofilm microorganisms change phenotype and thus are less susceptible to antibiotic treatment and biofilm infections can become severe. The aim of this study was to determine if the presence of multikingdom microorganisms alters the virulence of a biofilm infection in a host organism. The coexistence of Candida albicans and Staphylococcus epidermidis in biofilm was examined in the nematode model Caenorhabditis elegans. It was evaluated if the hyphal form of C. albicans and extracellular polymeric substances (EPS) formed by S. epidermidis increases biofilm virulence. Survival assays were performed, where C. elegans nematodes were exposed to S. epidermidis and C. albicans. Single inoculation assays showed a decreased survival rate after 2 days following exposure, while dual inoculation assays showed that a clinical S. epidermidis strain together with C. albicans significantly increased the virulence and decreased nematode survival. EPS seem to interfere with the bacterial attachment to hyphae, since the EPS overproducing S. epidermidis strain was most virulent. The clinical S. epidermidis paired with C. albicans led to a severe infection in the nematodes resulting in reduced survival. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Influence of Hyphal Inoculum potential on the Competitive Success of Fungi Colonizing Wood.

    Science.gov (United States)

    Song, Zewei; Vail, Andrew; Sadowsky, Michael J; Schilling, Jonathan S

    2015-05-01

    The relative amounts of hyphal inoculum in forest soils may determine the capacity for fungi to compete with and replace early colonizers of wood in ground contact. Our aim in this study was to test the flexibility of priority effects (colonization timing) by varying the timing of inoculum introduction (i.e., precolonization) and amount of inoculum (i.e., inoculum potential). We controlled these variables in soil-block microcosms using fungi with known competitive outcomes in similar conditions, tracking isolate-specific fungal biomass, and residue physiochemistry over time. In the precolonization trial (experiment I), a brown rot fungus Gloeophyllum trabeum was given 1, 3, or 5 weeks to precolonize wood blocks (oak, birch, pine, and spruce) prior the introduction of a white rot fungus, Irpex lacteus, a more aggressive colonizer in this set-up. In the inoculum potential trial (experiment II), the fungi were inoculated simultaneously, but with eightfold higher brown rot inoculum than that of experiment I. As expected, longer precolonization duration increased the chance for the less-competitive brown rot fungus to outcompete its white rot opponent. Higher brown rot fungal inoculum outside of the wood matrix also resulted in competitive success for the brown rot isolate in most cases. These temporal shifts in fungal dominance were detectable in a 'community snapshot' as isolate-specific quantitative PCR, but also as functionally-relevant consequences of wood rot type, including carbohydrate depolymerization and pH. These results from a controlled system reinforce fungal-fungal interaction and suggest that relative inoculum availability beyond the wood matrix (i.e., soils) might regulate the duration of priority effects and shift the functional trajectory of wood decomposition.

  1. A novel immune evasion strategy of candida albicans: proteolytic cleavage of a salivary antimicrobial peptide.

    Directory of Open Access Journals (Sweden)

    Timothy F Meiller

    Full Text Available Oropharyngeal candidiasis is an opportunistic infection considered to be a harbinger of AIDS. The etiologic agent Candida albicans is a fungal species commonly colonizing human mucosal surfaces. However, under conditions of immune dysfunction, colonizing C. albicans can become an opportunistic pathogen causing superficial or even life-threatening infections. The reasons behind this transition, however, are not clear. In the oral cavity, salivary antimicrobial peptides are considered to be an important part of the host innate defense system in the prevention of microbial colonization. Histatin-5 specifically has exhibited potent activity against C. albicans. Our previous studies have shown histatin-5 levels to be significantly reduced in the saliva of HIV+ individuals, indicating an important role for histatin-5 in keeping C. albicans in its commensal stage. The versatility in the pathogenic potential of C. albicans is the result of its ability to adapt through the regulation of virulence determinants, most notably of which are proteolytic enzymes (Saps, involved in tissue degradation. In this study, we show that C. albicans cells efficiently and rapidly degrade histatin-5, resulting in loss of its anti-candidal potency. In addition, we demonstrate that this cellular activity is due to proteolysis by a member of the secreted aspartic proteases (Sap family involved in C. albicans pathogenesis. Specifically, the proteolysis was attributed to Sap9, in turn identifying histatin-5 as the first host-specific substrate for that isoenzyme. These findings demonstrate for the first time the ability of a specific C. albicans enzyme to degrade and deactivate a host antimicrobial peptide involved in the protection of the oral mucosa against C. albicans, thereby providing new insights into the factors directing the transition of C. albicans from commensal to pathogen, with important clinical implications for alternative therapy. This report characterizes the

  2. Hyphal Growth from Spores of the Mycorrhizal Fungus Glomus Caledonius: Effect of Amino Acids

    DEFF Research Database (Denmark)

    Hepper, C.M.; Jakobsen, Iver

    1983-01-01

    Hyphal growth from spores of Glomus caledonius (Nicol. and Gerd.) Trappe and Gerdemann was stimulated by cystine, glycine and lysine at optimum concentrations of 4.6, 556 and 825 mg l−1 respectively. When all three amino acids were supplied together in water agar, five times more growth...

  3. Effect of the Ethyl Acetate Fraction of Eugenia uniflora on Proteins Global Expression during Morphogenesis in Candida albicans.

    Science.gov (United States)

    Silva-Rocha, Walicyranison P; de Azevedo, Matheus F; Ferreira, Magda R A; da Silva, Julhiany de Fátima; Svidzinski, Terezinha I E; Milan, Eveline P; Soares, Luiz A L; Rocha, Keyla B F; Uchôa, Adriana F; Mendes-Giannini, Maria J S; Fusco Almeida, Ana M; Chaves, Guilherme M

    2017-01-01

    Candida albicans is able to switch from yeast to hyphal growth and this is an essential step for tissue invasion and establishment of infection. Due to the limited drug arsenal used to treat fungal infections and the constant emergence of resistant strains, it is important to search for new therapeutic candidates. Therefore, this study aimed to investigate by proteomic analysis the role of a natural product ( Eugenia uniflora ) in impairing hypha formation in C. albicans . We also tested the potential action of E. uniflora to prevent and treat oral candidiasis induced in a murine model of oral infection and the ability of polymorphonuclear neutrophils to phagocytize C. albicans cells treated with the ethyl acetate fraction of the extract. We found that this fraction greatly reduced hypha formation after morphogenesis induction in the presence of serum. Besides, several proteins were differentially expressed in cells treated with the fraction. Surprisingly, the ethyl acetate fraction significantly reduced phagocytosis in C. albicans (Mean 120.36 ± 36.71 yeasts/100 PMNs vs. 44.68 ± 19.84 yeasts/100 PMNs). Oral candidiasis was attenuated when C. albicans cells were either pre-incubated in the presence of E. uniflora or when the fraction was applied to the surface of the oral cavity after infection. These results were consistent with the reduction in CFU counts (2.36 vs. 1.85 Log10 CFU/ml) and attenuation of tissue damage observed with histopathological analysis of animals belonging to treated group. We also observed shorter true hyphae by direct examination and histopathological analysis, when cells were treated with the referred natural product. The E. uniflora ethyl acetate fraction was non-toxic to human cells. E. uniflora may act on essential proteins mainly related to cellular structure, reducing the capacity of filamentation and attenuating infection in a murine model, without causing any toxic effect on human cells, suggesting that it may be a future

  4. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Shruthi Ramachandra

    Full Text Available Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA, representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA. In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.

  5. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans.

    Science.gov (United States)

    Ramachandra, Shruthi; Linde, Jörg; Brock, Matthias; Guthke, Reinhard; Hube, Bernhard; Brunke, Sascha

    2014-01-01

    Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA), representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA). In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.

  6. Germination of hyphal bodies of Pythium spiculum isolated from declining cork oaks at Doñana National Park (Spain

    Directory of Open Access Journals (Sweden)

    PAOLO DE VITA

    2012-01-01

    Full Text Available Pythium spiculum, a recently described new taxon, has been isolated from declining cork oaks (Quercus suber L. at Doñana National Park (south-western Spain. The microorganism can infect and cause root disease in Quercus, but currently it is unknown whether its hyphal bodies can germinate and infect host trees. These hyphal bodies, regardless of shape, have been shown to be able to germinate, producing long germ tubes, sometimes ramified. Zoospore production was not recorded, but hyphal bodies are potential host infective structures in dry soil conditions.

  7. The novel Candida albicans transporter Dur31 Is a multi-stage pathogenicity factor.

    Directory of Open Access Journals (Sweden)

    François L Mayer

    Full Text Available Candida albicans is the most frequent cause of oral fungal infections. However, the exact pathogenicity mechanisms that this fungus employs are largely unknown and many of the genes expressed during oral infection are uncharacterized. In this study we sought to functionally characterize 12 previously unknown function genes associated with oral candidiasis. We generated homozygous knockout mutants for all 12 genes and analyzed their interaction with human oral epithelium in vitro. Eleven mutants caused significantly less epithelial damage and, of these, deletion of orf19.6656 (DUR31 elicited the strongest reduction in pathogenicity. Interestingly, DUR31 was not only involved in oral epithelial damage, but in multiple stages of candidiasis, including surviving attack by human neutrophils, endothelial damage and virulence in vivo. In silico analysis indicated that DUR31 encodes a sodium/substrate symporter with 13 transmembrane domains and no human homologue. We provide evidence that Dur31 transports histatin 5. This is one of the very first examples of microbial driven import of this highly cytotoxic antimicrobial peptide. Also, in contrast to wild type C. albicans, dur31Δ/Δ was unable to actively increase local environmental pH, suggesting that Dur31 lies in the extracellular alkalinization hyphal auto-induction pathway; and, indeed, DUR31 was required for morphogenesis. In agreement with this observation, dur31Δ/Δ was unable to assimilate the polyamine spermidine.

  8. Serum repressing efflux pump CDR1 in Candida albicans

    Directory of Open Access Journals (Sweden)

    Fan Jen-Chung

    2006-07-01

    Full Text Available Abstract Background In the past decades, the prevalence of candidemia has increased significantly and drug resistance has also become a pressing problem. Overexpression of CDR1, an efflux pump, has been proposed as a major mechanism contributing to the drug resistance in Candida albicans. It has been demonstrated that biological fluids such as human serum can have profound effects on antifungal pharmacodynamics. The aim of this study is to understand the effects of serum in drug susceptibility via monitoring the activity of CDR1 promoter of C. albicans. Results The wild-type C. albicans cells (SC5314 but not the cdr1/cdr1 mutant cells became more susceptible to the antifungal drug when the medium contained serum. To understand the regulation of CDR1 in the presence of serum, we have constructed CDR1 promoter-Renilla luciferase (CDR1p-RLUC reporter to monitor the activity of the CDR1 promoter in C. albicans. As expected, the expression of CDR1p-RLUC was induced by miconazole. Surprisingly, it was repressed by serum. Consistently, the level of CDR1 mRNA was also reduced in the presence of serum but not N-acetyl-D-glucosamine, a known inducer for germ tube formation. Conclusion Our finding that the expression of CDR1 is repressed by serum raises the question as to how does CDR1 contribute to the drug resistance in C. albicans causing candidemia. This also suggests that it is important to re-assess the prediction of in vivo therapeutic outcome of candidemia based on the results of standard in vitro antifungal susceptibility testing, conducted in the absence of serum.

  9. Differential virulence of Candida albicans and C. dubliniensis: A role for Tor1 kinase?

    LENUS (Irish Health Repository)

    Sullivan, Derek J

    2011-01-01

    Candida albicans and Candida dubliniensis are two very closely related species of pathogenic yeast. C. albicans is the most prevalent species in the human gastrointestinal tract and is responsible for far more opportunistic infections in comparison with C. dubliniensis. This disparity is likely to be due to the reduced ability of C. dubliniensis to undergo the yeast to hypha transition, a change in morphology that plays an important role in C. albicans virulence. We have recently shown that hypha formation by C. dubliniensis is specifically repressed by nutrients at alkaline pH. In this article, we present new data showing that this can be partly reversed by treatment with rapamycin, an inhibitor of the nutrient sensing kinase Tor1 (Target Of Rapamycin). We also provide a speculative model to describe why C. albicans filaments more efficiently in nutrient rich environments, citing recently described data on Mds3, a pH responsive regulator of Tor1 kinase activity.

  10. Calcineurin Orchestrates Hyphal Growth, Septation, Drug Resistance and Pathogenesis of Aspergillus fumigatus: Where Do We Go from Here?

    Directory of Open Access Journals (Sweden)

    Praveen R Juvvadi

    2015-12-01

    Full Text Available Studies on fungal pathogens belonging to the ascomycota phylum are critical given the ubiquity and frequency with which these fungi cause infections in humans. Among these species, Aspergillus fumigatus causes invasive aspergillosis, a leading cause of death in immunocompromised patients. Fundamental to A. fumigatus pathogenesis is hyphal growth. However, the precise mechanisms underlying hyphal growth and virulence are poorly understood. Over the past 10 years, our research towards the identification of molecular targets responsible for hyphal growth, drug resistance and virulence led to the elucidation of calcineurin as a key signaling molecule governing these processes. In this review, we summarize our salient findings on the significance of calcineurin for hyphal growth and septation in A. fumigatus and propose future perspectives on exploiting this pathway for designing new fungal-specific therapeutics.

  11. Application of the systematic "DAmP" approach to create a partially defective C. albicans mutant.

    Science.gov (United States)

    Finkel, J S; Yudanin, N; Nett, J E; Andes, D R; Mitchell, A P

    2011-11-01

    An understanding of gene function often relies upon creating multiple kinds of alleles. Functional analysis in Candida albicans, a major fungal pathogen, has generally included characterization of mutant strains with insertion or deletion alleles and over-expression alleles. Here we use in C. albicans another type of allele that has been employed effectively in the model yeast Saccharomyces cerevisiae, a "Decreased Abundance by mRNA Perturbation" (DAmP) allele (Yan et al., 2008). DAmP alleles are created systematically through replacement of 30 noncoding regions with nonfunctional heterologous sequences, and thus are broadly applicable. We used a DAmP allele to probe the function of Sun41, a surface protein with roles in cell wall integrity, cell-cell adherence, hyphal formation, and biofilm formation that has been suggested as a possible therapeutic target (Firon et al., 2007; Hiller et al., 2007; Norice et al., 2007). A SUN41-DAmP allele results in approximately 10-fold reduced levels of SUN41 RNA, and yields intermediate phenotypes in most assays. We report that a sun41Δ/Δ mutant is defective in biofilm formation in vivo, and that the SUN41-DAmP allele complements that defect. This finding argues that Sun41 may not be an ideal therapeutic target for biofilm inhibition, since a 90% decrease in activity has little effect on biofilm formation in vivo. We anticipate that DAmP alleles of C. albicans genes will be informative for analysis of other prospective drug targets, including essential genes.

  12. Coordination of Candida albicans Invasion and Infection Functions by Phosphoglycerol Phosphatase Rhr2

    Directory of Open Access Journals (Sweden)

    Jigar V. Desai

    2015-07-01

    Full Text Available The Candida albicans RHR2 gene, which specifies a glycerol biosynthetic enzyme, is required for biofilm formation in vitro and in vivo. Prior studies indicate that RHR2 is ultimately required for expression of adhesin genes, such as ALS1. In fact, RHR2 is unnecessary for biofilm formation when ALS1 is overexpressed from an RHR2-independent promoter. Here, we describe two additional biological processes that depend upon RHR2: invasion into an abiotic substrate and pathogenicity in an abdominal infection model. We report here that abiotic substrate invasion occurs concomitantly with biofilm formation, and a screen of transcription factor mutants indicates that biofilm and hyphal formation ability correlates with invasion ability. However, analysis presented here of the rhr2Δ/Δ mutant separates biofilm formation and invasion. We found that an rhr2Δ/Δ mutant forms a biofilm upon overexpression of the adhesin gene ALS1 or the transcription factor genes BRG1 or UME6. However, the biofilm-forming strains do not invade the substrate. These results indicate that RHR2 has an adhesin-independent role in substrate invasion, and mathematical modeling argues that RHR2 is required to generate turgor. Previous studies have shown that abdominal infection by C. albicans has two aspects: infection of abdominal organs and persistence in abscesses. We report here that an rhr2Δ/Δ mutant is defective in both of these infection phenotypes. We find here that overexpression of ALS1 in the mutant restores infection of organs, but does not improve persistence in abscesses. Therefore, RHR2 has an adhesin-independent role in abdominal infection, just as it does in substrate invasion. This report suggests that RHR2, through glycerol synthesis, coordinates adherence with host- or substrate-interaction activities that enable proliferation of the C. albicans population.

  13. Increased hyphal branching and growth of ectomycorrhizal fungus Lactarius rufus by the helper bacterium Paenibacillus sp.

    Science.gov (United States)

    Aspray, T J; Jones, E E; Davies, M W; Shipman, M; Bending, G D

    2013-07-01

    Paenibacillus sp. EJP73 has been previously demonstrated as a mycorrhization helper bacterium (MHB) for the Lactarius rufus-Pinus sylvestris symbiosis in both laboratory and glasshouse experiments. In the present study, the effect of Paenibacillus sp. EJP73 metabolites on L. rufus EO3 pre-symbiotic growth was tested in two agar plate-based systems. Specifically, volatile metabolites were investigated using a dual plate system, in which the presence of strain EJP73 resulted in a significant negative effect on L. rufus EO3 hyphal radial growth but enhanced hyphal branching and reduced internode distance. Soluble metabolites produced by strain EJP73 were tested on L. rufus EO3 growth in single-agar plate assays by incorporating bacterial cell-free whole or molecular weight fraction spent broth into the agar. Whole spent broth had a negative effect on hyphal growth, whereas a low molecular weight fraction (100-1,000) promoted colony radial growth. Headspace and spent broth analysis of strain EJP73 cultures revealed 2,5-diisopropylpyrazine to be the most significant component. Synthesised 2,5-diisopropylpyrazine and elevated CO2 (2,000 ppm) were tested as specific volatile metabolites in the dual plate system, but neither produced the response shown when strain EJP73 was present. Increased pre-symbiotic hyphal branching leading to increased likelihood of plant infection may be an important MHB mechanism for strain EJP73. Although the precise signal molecules could not be identified, the work suggests a number of metabolites may work synergistically to increase L. rufus root colonisation.

  14. Inner Leaf Gel of Aloe striata Induces Adhesion-Reducing Morphological Hyphal Aberrations

    Directory of Open Access Journals (Sweden)

    Gloria Wada

    2018-02-01

    Full Text Available Fungi, particularly molds that are cosmopolitan in soils, are frequent etiologic agents of opportunistic mycoses. Members of the Fusarium solani and Fusarium oxysporum species complexes are the most commonly implicated etiologic agents of opportunistic fusarial infections in mammals, while Paecilomyces variotii is one of the most frequently encountered Paecilomyces species in human infections. Prevention and treatment of these mycoses are problematic because available antimycotics are limited and often have toxic side effects. Popular folk medicines, such as the inner leaf gel from Aloe spp., offer potential sources for novel antimycotic compounds. To screen for antifungal properties of Aloe striata, we treated conidia of three strains each of F. solani, F. oxysporum, and P. variotii with homogenized and filtered inner leaf gel. Exposure to gel homogenates caused minimal inhibition of conidial germination in tested strains. However, it significantly increased the frequency of hyphal aberrations characterized by increased hyphal diameters that resulted in intervals of non-parallel cell walls. Non-parallel cell walls ostensibly reduce total hyphal surface area available for adhesion. We found a significant decrease in the ability of aberrated P. variotii hyphae to remain adhered to microscope slides after repeated washing with reverse osmosis water. Our results suggest that treatment with A. striata contributes to a decrease in the adhesion frequency of tested P. variotii strains.

  15. A microscopy study of hyphal growth of Penicillium rubens on gypsum under dynamic humidity conditions.

    Science.gov (United States)

    van Laarhoven, Karel A; Huinink, Hendrik P; Adan, Olaf C G

    2016-05-01

    To remediate indoor fungal growth, understanding the moisture relations of common indoor fungi is crucial. Indoor moisture conditions are commonly quantified by the relative humidity (RH). RH is a major determinant of the availability of water in porous indoor surfaces that fungi grow on. The influence of steady-state RH on growth is well understood. Typically, however, the indoor RH constantly changes so that fungi have to endure frequent periods of alternating low and high RH. Knowledge of how common indoor fungi survive and are affected by the low-RH periods is limited. In particular, the specific effects of a drop in RH on the growth of the mycelium remain unclear. In this work, video microscopy was used to monitor hyphal growth of Penicillium rubens on gypsum substrates under controlled dynamic humidity conditions. The effect of a single period of low RH (RH = 50-90%) interrupting favourable conditions (RH = 97%) was tested. It was found that hyphal tips ceased to extend when exposed to any tested decrease in RH. However, new hyphal growth always emerges, seemingly from the old mycelium, suggesting that this indoor fungus does not rely only on conidia to survive the humidity patterns considered. These findings are a fundamental step in unravelling the effect of RH on indoor fungal growth. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  16. Candida albicans escapes from mouse neutrophils

    DEFF Research Database (Denmark)

    Ermert, David; Niemiec, Maria J; Röhm, Marc

    2013-01-01

    Candida albicans, the most commonly isolated human fungal pathogen, is able to grow as budding yeasts or filamentous forms, such as hyphae. The ability to switch morphology has been attributed a crucial role for the pathogenesis of C. albicans. To mimic disseminated candidiasis in humans, the mou...

  17. The Functions of Mediator in Candida albicans Support a Role in Shaping Species-Specific Gene Expression

    Science.gov (United States)

    Jelicic, Branka; Lo, Tricia L.; Beaurepaire, Cecile; Bantun, Farkad; Quenault, Tara; Boag, Peter R.; Ramm, Georg; Callaghan, Judy; Beilharz, Traude H.; Nantel, André; Peleg, Anton Y.; Traven, Ana

    2012-01-01

    The Mediator complex is an essential co-regulator of RNA polymerase II that is conserved throughout eukaryotes. Here we present the first study of Mediator in the pathogenic fungus Candida albicans. We focused on the Middle domain subunit Med31, the Head domain subunit Med20, and Srb9/Med13 from the Kinase domain. The C. albicans Mediator shares some roles with model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, such as functions in the response to certain stresses and the role of Med31 in the expression of genes regulated by the activator Ace2. The C. albicans Mediator also has additional roles in the transcription of genes associated with virulence, for example genes related to morphogenesis and gene families enriched in pathogens, such as the ALS adhesins. Consistently, Med31, Med20, and Srb9/Med13 contribute to key virulence attributes of C. albicans, filamentation, and biofilm formation; and ALS1 is a biologically relevant target of Med31 for development of biofilms. Furthermore, Med31 affects virulence of C. albicans in the worm infection model. We present evidence that the roles of Med31 and Srb9/Med13 in the expression of the genes encoding cell wall adhesins are different between S. cerevisiae and C. albicans: they are repressors of the FLO genes in S. cerevisiae and are activators of the ALS genes in C. albicans. This suggests that Mediator subunits regulate adhesion in a distinct manner between these two distantly related fungal species. PMID:22496666

  18. The functions of Mediator in Candida albicans support a role in shaping species-specific gene expression.

    Directory of Open Access Journals (Sweden)

    Nathalie Uwamahoro

    Full Text Available The Mediator complex is an essential co-regulator of RNA polymerase II that is conserved throughout eukaryotes. Here we present the first study of Mediator in the pathogenic fungus Candida albicans. We focused on the Middle domain subunit Med31, the Head domain subunit Med20, and Srb9/Med13 from the Kinase domain. The C. albicans Mediator shares some roles with model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, such as functions in the response to certain stresses and the role of Med31 in the expression of genes regulated by the activator Ace2. The C. albicans Mediator also has additional roles in the transcription of genes associated with virulence, for example genes related to morphogenesis and gene families enriched in pathogens, such as the ALS adhesins. Consistently, Med31, Med20, and Srb9/Med13 contribute to key virulence attributes of C. albicans, filamentation, and biofilm formation; and ALS1 is a biologically relevant target of Med31 for development of biofilms. Furthermore, Med31 affects virulence of C. albicans in the worm infection model. We present evidence that the roles of Med31 and Srb9/Med13 in the expression of the genes encoding cell wall adhesins are different between S. cerevisiae and C. albicans: they are repressors of the FLO genes in S. cerevisiae and are activators of the ALS genes in C. albicans. This suggests that Mediator subunits regulate adhesion in a distinct manner between these two distantly related fungal species.

  19. Antifungal activity and influence of propolis against germ tube formation as a critical virulence attribute by clinical isolates of Candida albicans.

    Science.gov (United States)

    Haghdoost, N S; Salehi, T Z; Khosravi, A; Sharifzadeh, A

    2016-12-01

    The potentiality to switch between yeast and hyphal morphologies plays an important role in the virulence of Candida albicans (C. albicans). The objective of the present study was to evaluate the chemical composition, antifungal activity and influence of propolis upon germ tube formation of C. albicans clinical isolates. The major compounds of propolis ethanolic extract (PEE) was revealed by gas chromatography-mass spectrometry (GC/MS) analysis. Broth microdilution method was used for determination of minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of this extract. C. albicans isolates were exposed to sub-MIC concentrations of propolis and germ tube reduction percent (GRP) and morphological transition from yeast to filamentous form were monitored microscopically. Phenolic compounds, aromatic acids, aliphatic acids, sugars and polycyclic aromatic hydrocarbons were the major compound classes in PEE. Mean of MIC and MFC values of PEE against C. albicans isolates were 360.6μg·mL -1 and 1250.1μg·mL -1 , respectively. The increase in concentration led to a significant reduction in germ tube formation, so mean of GRP was 36.7±11.1 and 22±10.1 at concentration of ½ MIC and ¼ MIC of PEE, respectively. In conclusion, the present study indicated that PEE has interesting potential as a therapeutic agent that targets germ tube formation by C. albicans as a critical virulence factor. Copyright © 2016. Published by Elsevier Masson SAS.

  20. Limonene inhibits Candida albicans growth by inducing apoptosis.

    Science.gov (United States)

    Thakre, Archana; Zore, Gajanan; Kodgire, Santosh; Kazi, Rubina; Mulange, Shradha; Patil, Rajendra; Shelar, Amruta; Santhakumari, Bayitigeri; Kulkarni, Mahesh; Kharat, Kiran; Karuppayil, Sankunny Mohan

    2017-10-09

    Anti-Candida potential of limonene was evaluated against planktonic growth, biofilm (adhesion, development and maturation) and morphogenesis of Candida albicans in this study. Limonene is a major constituent of citrus oil and most frequently used terpene in food and beverage industry due to its pleasant fragrance, nontoxic, and is generally recognized as safe (GRAS) flavoring agent as well as treatment option in many gastrointestinal diseases.Limonene exhibited excellent anti-Candida activity and was equally effective against planktonic growth of C. albicans isolates differentially susceptible to FLC (N = 35). Limonene inhibited morphogenesis significantly at low concentration. However, it showed stage dependent activity against biofilm formation, that is, it was more effective against adhesion followed by development and maturation. Limonene also exhibited excellent synergy with FLC against planktonic and biofilm growth. SWATH-MS analysis led to identification of limonene responsive proteins that provided molecular insight of its anti-Candida activity. Proteomic analysis revealed upregulation of proteins involved in cell wall glucan synthesis (Kre6); oxidative stress (Rhr2, Adh7 and Ebp1); DNA damage stress (Mbf1 and Npl3); nucleolar stress (Rpl11, Rpl7, Rpl29, Rpl15) and down regulation of cytoskeleton organization (Crn1, Pin3, Cct8, Rbl2), and so forth, in response to limonene. Limonene mediated down regulation of Tps3 indicates activation of caspase (CaMca1) and induction of apoptosis in C. albicans. These results suggest that limonene inhibits C. albicans growth by cell wall/membrane damage induced oxidative stress that leads to DNA damage resulting into modulation of cell cycle and induction of apoptosis through nucleolar stress and metacaspase dependent pathway. © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Lipopolysaccharide-induced M2 to M1 macrophage transformation for IL-12p70 production is blocked by Candida albicans mediated up-regulation of EBI3 expression.

    Directory of Open Access Journals (Sweden)

    Xing-Feng Zheng

    Full Text Available Macrophages are heterogeneous cell populations that are present in all tissues. Macrophages can be divided into classically activated inflammatory macrophages (M1 and alternatively activated anti-inflammatory macrophages (M2. It has been generally accepted that M1 macrophages are polarised in an inflammatory environment to produce pro-inflammatory cytokines, whilst M2 macrophages are involved in anti-inflammation and aid tissue repair in wound healing. Bacterial endotoxin (lipopolysaccharide; LPS is a potent factor in infection, which induces M1 macrophages resulting in higher levels of iNOS, TNFα and IL-12p70 which dictate inflammatory T cell responses. M2 macrophages can be transformed into M1 macrophages following LPS stimulation to promote inflammation. Candida albicans is a commensal fungal microorganism, which has been suggested to induce immune tolerance; however, the mechanism of C. albicans-induced immune tolerance has not been investigated in detail. IL-35 is a recently identified anti-inflammatory cytokine which is a heterodimeric protein consisting of the Epstein-Barr virus-induced gene 3 (EBI3 and IL-12p35. IL-35 shares the protein subunit p35, with IL-12p70. IL-12p70 is the most potent cytokine to induce Th1 responses during inflammation. In this study, we demonstrate that heat-killed C. albicans (HKC strongly suppressed LPS-induced IL-12p70 production in M2 macrophages. Candida albicans induced a high level of EBI3 expression in M2 macrophages, which served as a mechanism for IL-12p70 suppression by competitive binding of the common protein subunit (p35 of IL-35 and IL-12p70. To demonstrate that EBI3 expression had the ability to block IL-12p70 production intracellularly, a Chinese Hamster Ovary (CHO cell line with biscistronic expression of IL-12p40 and p35 was constructed, followed by ectopic over-expression of EBI3. The over-expression of EBI3 in the IL-12p70 producing cell line effectively suppressed IL-12p70 production. IL

  2. Role of Ess1 in growth, morphogenetic switching, and RNA polymerase II transcription in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Dhanushki Samaranayake

    Full Text Available Candida albicans is a fungal pathogen that causes potentially fatal infections among immune-compromised individuals. The emergence of drug resistant C. albicans strains makes it important to identify new antifungal drug targets. Among potential targets are enzymes known as peptidyl-prolyl cis/trans isomerases (PPIases that catalyze isomerization of peptide bonds preceding proline. We are investigating a PPIase called Ess1, which is conserved in all major human pathogenic fungi. Previously, we reported that C. albicans Ess1 is essential for growth and morphogenetic switching. In the present study, we re-evaluated these findings using more rigorous genetic analyses, including the use of additional CaESS1 mutant alleles, distinct marker genes, and the engineering of suitably-matched isogenic control strains. The results confirm that CaEss1 is essential for growth in C. albicans, but show that reduction of CaESS1 gene dosage by half (δ/+ does not interfere with morphogenetic switching. However, further reduction of CaEss1 levels using a conditional allele does reduce morphogenetic switching. We also examine the role of the linker α-helix that distinguishes C. albicans Ess1 from the human Pin1 enzyme, and present results of a genome-wide transcriptome analysis. The latter analysis indicates that CaEss1 has a conserved role in regulation of RNA polymerase II function, and is required for efficient termination of small nucleolar RNAs and repression of cryptic transcription in C. albicans.

  3. Comparative Phenotypic Analysis of the Major Fungal Pathogens Candida parapsilosis and Candida albicans

    Science.gov (United States)

    Holland, Linda M.; Schröder, Markus S.; Turner, Siobhán A.; Taff, Heather; Andes, David; Grózer, Zsuzsanna; Gácser, Attila; Ames, Lauren; Haynes, Ken; Higgins, Desmond G.; Butler, Geraldine

    2014-01-01

    Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis. PMID:25233198

  4. A role for Candida albicans superoxide dismutase enzymes in glucose signaling.

    Science.gov (United States)

    Broxton, Chynna N; He, Bixi; Bruno, Vincent M; Culotta, Valeria C

    2018-01-01

    The Saccharomyces cerevisiae and Candida albicans yeasts have evolved to differentially use glucose for fermentation versus respiration. S. cerevisiae is Crabtree positive, where glucose represses respiration and promotes fermentation, while the opportunistic fungal pathogen C. albicans is Crabtree negative and does not repress respiration with glucose. We have previously shown that glucose control in S. cerevisiae involves the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1), where H 2 O 2 generated by SOD1 stabilizes the casein kinase YCK1 for glucose sensing. We now demonstrate that C. albicans SODs also participate in glucose regulation. C. albicans expresses two cytosolic SODs, Cu/Zn SOD1 and Mn containing SOD3, and both complemented a S. cerevisiae sod1Δ mutant in stabilizing YCK1. Moreover, in C. albicans cells, both SODs functioned to repress glucose transporter genes in response to glucose. However, the action of SODs in glucose control has diverged in the two yeasts. In S. cerevisiae, SOD1 specifically functions in the glucose sensing pathway involving YCK1 and the RGT1 repressor, but the analogous YCK/RGT1 pathway in C. albicans shows no control by SOD enzymes. Instead C. albicans SODs work in the glucose repression pathway involving the MIG1 transcriptional repressor. In C. albicans, the SODs repress glucose uptake, while in S. cerevisiae, SOD1 activates glucose uptake, in accordance with the divergent modes for glucose utilization in these two distantly related yeasts. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Hydrolytic enzymes as virulence factors of Candida albicans.

    Science.gov (United States)

    Schaller, Martin; Borelli, Claudia; Korting, Hans C; Hube, Bernhard

    2005-11-01

    Candida albicans is a facultative pathogenic micro-organism that has developed several virulence traits enabling invasion of host tissues and avoidance of host defence mechanisms. Virulence factors that contribute to this process are the hydrolytic enzymes. Most of them are extracellularly secreted by the fungus. The most discussed hydrolytic enzymes produced by C. albicans are secreted aspartic proteinases (Saps). The role of these Saps for C. albicans infections was carefully evaluated in numerous studies, whereas only little is known about the physiological role of the secreted phospholipases (PL) and almost nothing about the involvement of lipases (Lip) in virulence. They may play an important role in the pathogenicity of candidosis and their hydrolytic activity probably has a number of possible functions in addition to the simple role of digesting molecules for nutrition. Saps as the best-studied member of this group of hydrolytic enzymes contribute to host tissue invasion by digesting or destroying cell membranes and by degrading host surface molecules. There is also some evidence that hydrolytic enzymes are able to attack cells and molecules of the host immune system to avoid or resist antimicrobial activity. High hydrolytic activity with broad substrate specificity has been found in several Candida species, most notably in C. albicans. This activity is attributed to multigene families with at least 10 members for Saps and Lips and several members for PL B. Distinct members of these gene families are differentially regulated in various Candida infections. In future, prevention and control of Candida infections might be achieved by pharmacological or immunological tools specifically modulated to inhibit virulence factors, e.g. the family of Saps.

  6. Adaptation of Candida albicans to Reactive Sulfur Species.

    Science.gov (United States)

    Chebaro, Yasmin; Lorenz, Michael; Fa, Alice; Zheng, Rui; Gustin, Michael

    2017-05-01

    Candida albicans is an opportunistic fungal pathogen that is highly resistant to different oxidative stresses. How reactive sulfur species (RSS) such as sulfite regulate gene expression and the role of the transcription factor Zcf2 and the sulfite exporter Ssu1 in such responses are not known. Here, we show that C. albicans specifically adapts to sulfite stress and that Zcf2 is required for that response as well as induction of genes predicted to remove sulfite from cells and to increase the intracellular amount of a subset of nitrogen metabolites. Analysis of mutants in the sulfate assimilation pathway show that sulfite conversion to sulfide accounts for part of sulfite toxicity and that Zcf2-dependent expression of the SSU1 sulfite exporter is induced by both sulfite and sulfide. Mutations in the SSU1 promoter that selectively inhibit induction by the reactive nitrogen species (RNS) nitrite, a previously reported activator of SSU1 , support a model for C. albicans in which Cta4-dependent RNS induction and Zcf2-dependent RSS induction are mediated by parallel pathways, different from S. cerevisiae in which the transcription factor Fzf1 mediates responses to both RNS and RSS. Lastly, we found that endogenous sulfite production leads to an increase in resistance to exogenously added sulfite. These results demonstrate that C. albicans has a unique response to sulfite that differs from the general oxidative stress response, and that adaptation to internal and external sulfite is largely mediated by one transcription factor and one effector gene. Copyright © 2017 by the Genetics Society of America.

  7. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces.

    Science.gov (United States)

    King, Robert; Urban, Martin; Lauder, Rebecca P; Hawkins, Nichola; Evans, Matthew; Plummer, Amy; Halsey, Kirstie; Lovegrove, Alison; Hammond-Kosack, Kim; Rudd, Jason J

    2017-10-01

    Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast "yeast-like" growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices.

  8. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces.

    Directory of Open Access Journals (Sweden)

    Robert King

    2017-10-01

    Full Text Available Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast "yeast-like" growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2. Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2 suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices.

  9. Induction of contour sensing in Aspergillus niger by stress and its relevance to fungal growth mechanics and hyphal tip structure.

    Science.gov (United States)

    Bowen, Andrew D; Davidson, Fordyce A; Keatch, Robert; Gadd, Geoffrey M

    2007-06-01

    Thigmotropism (contour sensing) has been assigned an important role in both plant and human fungal pathogens. However, outside these systems, our knowledge of the function of thigmotropism in fungal growth control is relatively poor. Furthermore, the effects of environmental stress on thigmotropic responses have received scant attention. To try to elucidate some of the mechanisms behind hyphal contour sensing in response to nutrient-poor environments, we have used micro-engineered substrates and several imaging techniques to investigate the thigmotropic reactions of the ubiquitous fungus Aspergillus niger. This organism not appear to demonstrate thigmotropic growth under normal conditions. Our results show that A. niger undergoes significant morphological changes during growth on solid substrates and demonstrate that the intensity of contour sensing varies depending on the area of the hyphal tip which initiates contact with the substrate. We propose that growth under nutrient-limited conditions triggers several factors that combine to increase thigmotropic sensitivity while conversely creating a 60 degrees arc at the hyphal tip which is blind to topographical variations. This has important consequences for our general understanding of the hyphal mode of growth in fungi as well as more specific aspects of hyphal tip development under stress.

  10. Different levels of hyphal self-incompatibility modulate interconnectedness of mycorrhizal networks in three arbuscular mycorrhizal fungi within the Glomeraceae.

    Science.gov (United States)

    Pepe, Alessandra; Giovannetti, Manuela; Sbrana, Cristiana

    2016-05-01

    Arbuscular mycorrhizal fungi (AMF) live in symbiosis with most plant species and produce underground extraradical hyphal networks functional in the uptake and translocation of mineral nutrients from the soil to host plants. This work investigated whether fungal genotype can affect patterns of interconnections and structural traits of extraradical mycelium (ERM), by comparing three Glomeraceae species growing in symbiosis with five plant hosts. An isolate of Funneliformis coronatus consistently showed low ability to form interconnected ERM and self-incompatibility that represented up to 21% of hyphal contacts. The frequency of post-fusion self-incompatible interactions, never detected before in AMF extraradical networks, was 8.9%. In F. coronatus ERM, the percentage of hyphal contacts leading to perfect hyphal fusions was 1.2-7.7, while it ranged from 25.8-48 to 35.6-53.6 in Rhizophagus intraradices and Funneliformis mosseae, respectively. Low interconnectedness of F. coronatus ERM resulted also from a very high number of non-interacting contacts (83.2%). Such findings show that AMF genotypes in Glomeraceae can differ significantly in anastomosis behaviour and that ERM interconnectedness is modulated by the fungal symbiont, as F. coronatus consistently formed poorly interconnected networks when growing in symbiosis with five different host plants and in the asymbiotic stage. Structural traits, such as extent, density and hyphal self-compatibility/incompatibility, may represent key factors for the differential performance of AMF, by affecting fungal absorbing surface and foraging ability and thus nutrient flow from soil to host roots.

  11. IFN-gamma in Candida albicans infections.

    Science.gov (United States)

    Gozalbo, Daniel; Gil, Maria Luisa

    2009-01-01

    The dimorphic fungus Candida albicans is the most frequent etiologic agent that causes opportunistic infections called candidiasis, a disease whose systemic manifestation could prove fatal and whose incidence is increasing as a result of an expanding immunocompromised population. Here we review the role of interferon-gamma (IFN-gamma) in the host protection against invasive candidiasis. This cytokine plays an essential role in both the innate and adaptive arms of the immune response to candidiasis. We focus on recent progress on host-pathogen interactions at the molecular level, leading to the production of IFN-gamma by host cells. IFN-gamma is produced by CD4 Th1, CD8, gamma delta T, and natural killer (NK) cells, essentially in response to both IL-12 and/or IL-18, and plays an important role in the regulation of the immune system as well as in the control of the infectious process. IFN-gamma is required for optimal activation of phagocytes, collaborates in the generation of protective antibody response, and favours the development of a Th1 protective response.

  12. Conserved and divergent roles of Bcr1 and CFEM proteins in Candida parapsilosis and Candida albicans.

    Directory of Open Access Journals (Sweden)

    Chen Ding

    Full Text Available Candida parapsilosis is a pathogenic fungus that is major cause of hospital-acquired infection, predominantly due to growth as biofilms on indwelling medical devices. It is related to Candida albicans, which remains the most common cause of candidiasis disease in humans. The transcription factor Bcr1 is an important regulator of biofilm formation in vitro in both C. parapsilosis and C. albicans. We show here that C. parapsilosis Bcr1 is required for in vivo biofilm development in a rat catheter model, like C. albicans. By comparing the transcription profiles of a bcr1 deletion in both species we found that regulation of expression of the CFEM family is conserved. In C. albicans, three of the five CFEM cell wall proteins (Rbt5, Pga7 and Csa1 are associated with both biofilm formation and acquisition of iron from heme, which is an important virulence characteristic. In C. parapsilosis, the CFEM family has undergone an expansion to 7 members. Expression of three genes (CFEM2, CFEM3, and CFEM6 is dependent on Bcr1, and is induced in low iron conditions. All three are involved in the acquisition of iron from heme. However, deletion of the three CFEM genes has no effect on biofilm formation in C. parapsilosis. Our data suggest that the role of the CFEM family in iron acquisition is conserved between C. albicans and C. parapsilosis, but their role in biofilm formation is not.

  13. Bioactive interleukin-1alpha is cytolytically released from Candida albicans-infected oral epithelial cells.

    Science.gov (United States)

    Dongari-Bagtzoglou, A; Kashleva, H; Villar, C Cunha

    2004-12-01

    Oral epithelial cells are primary targets of Candida albicans in the oropharynx and may regulate the inflammatory host response to this pathogen. This investigation studied the mechanisms underlying interleukin-1alpha (IL-1alpha) release by oral epithelial cells and the role of IL-1alpha in regulating the mucosal inflammatory response to C. albicans. Infected oral epithelial cells released processed IL-1alpha protein in culture supernatants. The IL-1alpha generated was stored intracellularly and was released upon cell lysis. This was further supported by the fact that different C. albicans strains induced variable IL-1alpha release, depending on their cytolytic activity. IL-1alpha from C. albicans-infected oral epithelial cells upregulated proinflammatory cytokine secretion (IL-8 and GM-CSF) in uninfected oral epithelial or stromal cells. Our studies suggest that production of IL-1alpha, IL-8 and GM-CSF may take place in the oral mucosa in response to lytic infection of epithelial cells with C. albicans. This process can act as an early innate immune surveillance system and may contribute to the clinicopathologic signs of infection in the oral mucosa.

  14. Human vaginal epithelial cells augment autophagy marker genes in response to Candida albicans infection.

    Science.gov (United States)

    Shroff, Ankit; Sequeira, Roicy; Reddy, Kudumula Venkata Rami

    2017-04-01

    Autophagy plays an important role in clearance of intracellular pathogens. However, no information is available on its involvement in vaginal infections such as vulvo-vaginal candidiasis (VVC). VVC is intimately associated with the immune status of the human vaginal epithelial cells (VECs). The objective of our study is to decipher if autophagy process is involved during Candida albicans infection of VECs. In this study, C. albicans infection system was established using human VEC line (VK2/E6E7). Infection-induced change in the expression of autophagy markers like LC3 and LAMP-1 were analyzed by RT-PCR, q-PCR, Western blot, immunofluorescence and transmission electron microscopy (TEM) studies were carried out to ascertain the localization of autophagosomes. Multiplex ELISA was carried out to determine the cytokine profiles. Analysis of LC3 and LAMP-1 expression at mRNA and protein levels at different time points revealed up-regulation of these markers 6 hours post C. albicans infection. LC3 and LAMP-1 puncti were observed in infected VECs after 12 hours. TEM studies showed C. albicans entrapped in autophagosomes. Cytokines-TNF-α and IL-1β were up-regulated in culture supernatants of VECs at 12 hours post-infection. The results suggest that C. albicans invasion led to the activation of autophagy as a host defense mechanism of VECs. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. The game theory of Candida albicans colonization dynamics reveals host status-responsive gene expression.

    Science.gov (United States)

    Tyc, Katarzyna M; Herwald, Sanna E; Hogan, Jennifer A; Pierce, Jessica V; Klipp, Edda; Kumamoto, Carol A

    2016-03-01

    The fungal pathogen Candida albicans colonizes the gastrointestinal (GI) tract of mammalian hosts as a benign commensal. However, in an immunocompromised host, the fungus is capable of causing life-threatening infection. We previously showed that the major transcription factor Efg1p is differentially expressed in GI-colonizing C. albicans cells dependent on the host immune status. To understand the mechanisms that underlie this host-dependent differential gene expression, we utilized mathematical modeling to dissect host-pathogen interactions. Specifically, we used principles of evolutionary game theory to study the mechanism that governs dynamics of EFG1 expression during C. albicans colonization. Mathematical modeling predicted that down-regulation of EFG1 expression within individual fungal cells occurred at different average rates in different hosts. Rather than using relatively transient signaling pathways to adapt to a new environment, we demonstrate that C. albicans overcomes the host defense strategy by modulating the activity of diverse fungal histone modifying enzymes that control EFG1 expression. Based on our modeling and experimental results we conclude that C. albicans cells sense the local environment of the GI tract and respond to differences by altering EFG1 expression to establish optimal survival strategies. We show that the overall process is governed via modulation of epigenetic regulators of chromatin structure.

  16. Laboratory and field methods for measurement of hyphal uptake of nutrients in soil

    DEFF Research Database (Denmark)

    Schweiger, P.F.; Jakobsen, I.

    2000-01-01

    Experimental systems for measuring nutrient transport by arbuscular mycorrhizal (AM) fungi in soil are described. The systems generally include two soil compartments that are separated by fine nylon mesh. Both roots and root-external hyphae grow in one compartment, but only hyphae are fine enough...... to grow through the mesh into the other compartment. Application of tracer isotopes to the soil of this hyphal compartment can be used to measure nutrient uptake by plants via AM fungal hyphae. Use of compartmented systems is discussed with particular reference to phosphorus, which is the mineral nutrient...

  17. Triclosan antagonises fluconazole activity against Candida albicans

    OpenAIRE

    MORAN, GARY

    2012-01-01

    Epub October 4th Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg/L. However, at subinhibitory concentrations (0.5-2 mg/L) triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1? and cdr2? strains. Triclosan did not affect fluconazole upt...

  18. Candida albicans Biofilms and Human Disease

    Science.gov (United States)

    Nobile, Clarissa J.; Johnson, Alexander D.

    2016-01-01

    In humans, microbial cells (including bacteria, archaea, and fungi) greatly outnumber host cells. Candida albicans is the most prevalent fungal species of the human microbiota; this species asymptomatically colonizes many areas of the body, particularly the gastrointestinal and genitourinary tracts of healthy individuals. Alterations in host immunity, stress, resident microbiota, and other factors can lead to C. albicans overgrowth, causing a wide range of infections, from superficial mucosal to hematogenously disseminated candidiasis. To date, most studies of C. albicans have been carried out in suspension cultures; however, the medical impact of C. albicans (like that of many other microorganisms) depends on its ability to thrive as a biofilm, a closely packed community of cells. Biofilms are notorious for forming on implanted medical devices, including catheters, pacemakers, dentures, and prosthetic joints, which provide a surface and sanctuary for biofilm growth. C. albicans biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental perturbations, making biofilm-based infections a significant clinical challenge. Here, we review our current knowledge of biofilms formed by C. albicans and closely related fungal species. PMID:26488273

  19. Integration of Posttranscriptional Gene Networks into Metabolic Adaptation and Biofilm Maturation in Candida albicans

    Science.gov (United States)

    Harrison, Paul F.; Lo, Tricia L.; Quenault, Tara; Dagley, Michael J.; Bellousoff, Matthew; Powell, David R.; Beilharz, Traude H.; Traven, Ana

    2015-01-01

    The yeast Candida albicans is a human commensal and opportunistic pathogen. Although both commensalism and pathogenesis depend on metabolic adaptation, the regulatory pathways that mediate metabolic processes in C. albicans are incompletely defined. For example, metabolic change is a major feature that distinguishes community growth of C. albicans in biofilms compared to suspension cultures, but how metabolic adaptation is functionally interfaced with the structural and gene regulatory changes that drive biofilm maturation remains to be fully understood. We show here that the RNA binding protein Puf3 regulates a posttranscriptional mRNA network in C. albicans that impacts on mitochondrial biogenesis, and provide the first functional data suggesting evolutionary rewiring of posttranscriptional gene regulation between the model yeast Saccharomyces cerevisiae and C. albicans. A proportion of the Puf3 mRNA network is differentially expressed in biofilms, and by using a mutant in the mRNA deadenylase CCR4 (the enzyme recruited to mRNAs by Puf3 to control transcript stability) we show that posttranscriptional regulation is important for mitochondrial regulation in biofilms. Inactivation of CCR4 or dis-regulation of mitochondrial activity led to altered biofilm structure and over-production of extracellular matrix material. The extracellular matrix is critical for antifungal resistance and immune evasion, and yet of all biofilm maturation pathways extracellular matrix biogenesis is the least understood. We propose a model in which the hypoxic biofilm environment is sensed by regulators such as Ccr4 to orchestrate metabolic adaptation, as well as the regulation of extracellular matrix production by impacting on the expression of matrix-related cell wall genes. Therefore metabolic changes in biofilms might be intimately linked to a key biofilm maturation mechanism that ultimately results in untreatable fungal disease. PMID:26474309

  20. Integration of Posttranscriptional Gene Networks into Metabolic Adaptation and Biofilm Maturation in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Jiyoti Verma-Gaur

    2015-10-01

    Full Text Available The yeast Candida albicans is a human commensal and opportunistic pathogen. Although both commensalism and pathogenesis depend on metabolic adaptation, the regulatory pathways that mediate metabolic processes in C. albicans are incompletely defined. For example, metabolic change is a major feature that distinguishes community growth of C. albicans in biofilms compared to suspension cultures, but how metabolic adaptation is functionally interfaced with the structural and gene regulatory changes that drive biofilm maturation remains to be fully understood. We show here that the RNA binding protein Puf3 regulates a posttranscriptional mRNA network in C. albicans that impacts on mitochondrial biogenesis, and provide the first functional data suggesting evolutionary rewiring of posttranscriptional gene regulation between the model yeast Saccharomyces cerevisiae and C. albicans. A proportion of the Puf3 mRNA network is differentially expressed in biofilms, and by using a mutant in the mRNA deadenylase CCR4 (the enzyme recruited to mRNAs by Puf3 to control transcript stability we show that posttranscriptional regulation is important for mitochondrial regulation in biofilms. Inactivation of CCR4 or dis-regulation of mitochondrial activity led to altered biofilm structure and over-production of extracellular matrix material. The extracellular matrix is critical for antifungal resistance and immune evasion, and yet of all biofilm maturation pathways extracellular matrix biogenesis is the least understood. We propose a model in which the hypoxic biofilm environment is sensed by regulators such as Ccr4 to orchestrate metabolic adaptation, as well as the regulation of extracellular matrix production by impacting on the expression of matrix-related cell wall genes. Therefore metabolic changes in biofilms might be intimately linked to a key biofilm maturation mechanism that ultimately results in untreatable fungal disease.

  1. Transportation of Aspergillus nidulans Class III and V Chitin Synthases to the Hyphal Tips Depends on Conventional Kinesin.

    Directory of Open Access Journals (Sweden)

    Norio Takeshita

    Full Text Available Cell wall formation and maintenance are crucial for hyphal morphogenesis. In many filamentous fungi, chitin is one of the main structural components of the cell wall. Aspergillus nidulans ChsB, a chitin synthase, and CsmA, a chitin synthase with a myosin motor-like domain (MMD at its N-terminus, both localize predominantly at the hyphal tip regions and at forming septa. ChsB and CsmA play crucial roles in polarized hyphal growth in A. nidulans. In this study, we investigated the mechanism by which CsmA and ChsB accumulate at the hyphal tip in living hyphae. Deletion of kinA, a gene encoding conventional kinesin (kinesin-1, impaired the localization of GFP-CsmA and GFP-ChsB at the hyphal tips. The transport frequency of GFP-CsmA and GFP-ChsB in both anterograde and retrograde direction appeared lower in the kinA-deletion strain compared to wild type, although the velocities of the movements were comparable. Co-localization of GFP-ChsB and GFP-CsmA with mRFP1-KinArigor, a KinA mutant that binds to microtubules but does not move along them, was observed in the posterior of the hyphal tip regions. KinA co-immunoprecipitated with ChsB and CsmA. Co-localization and association of CsmA with KinA did not depend on the MMD. These findings indicate that ChsB and CsmA are transported along microtubules to the subapical region by KinA.

  2. Hyphal-like extension and pseudohyphal formation in industrial strains of yeasts induced by isoamyl alcohol

    Directory of Open Access Journals (Sweden)

    Ceccato-Antonini Sandra Regina

    2002-01-01

    Full Text Available Yeasts can produce pseudohyphae and hyphal-like extensions under certain growth conditions like isoamyl alcohol (IAA induction, a chief constituent of fusel oil, which is a subproduct from the ethanolic fermentation. The morphology switch from yeast to a filamentous form can be troublesome to the process. In this work it was studied the influence of fusel alcohols, nitrogen sources (ammonium sulphate and leucine and glifosate (a chemical maturator for sugar cane added to a complex medium on some industrial strains of yeasts isolated from the fermentative process. Two industrial strains showed transition to hyphal-like extensions or pseudohyphae (clusters of cells upon addition of IAA from 0.3 to 0.9% /v. The alterations were reversible when the yeasts were reinoculated in YEPD without IAA. Although pseudohyphae are a result of nitrogen-limited medium, we observed them as a result of IAA addition. No influence of the nitrogen source or isopropilic alcohol or glifosate was detected for any strain studied in the concentrations used.

  3. Nuclear dynamics during germination, conidiation, and hyphal fusion of Fusarium oxysporum.

    Science.gov (United States)

    Ruiz-Roldán, M Carmen; Köhli, Michael; Roncero, M Isabel G; Philippsen, Peter; Di Pietro, Antonio; Espeso, Eduardo A

    2010-08-01

    In many fungal pathogens, infection is initiated by conidial germination. Subsequent stages involve germ tube elongation, conidiation, and vegetative hyphal fusion (anastomosis). Here, we used live-cell fluorescence to study the dynamics of green fluorescent protein (GFP)- and cherry fluorescent protein (ChFP)-labeled nuclei in the plant pathogen Fusarium oxysporum. Hyphae of F. oxysporum have uninucleated cells and exhibit an acropetal nuclear pedigree, where only the nucleus in the apical compartment is mitotically active. In contrast, conidiation follows a basopetal pattern, whereby mononucleated microconidia are generated by repeated mitotic cycles of the subapical nucleus in the phialide, followed by septation and cell abscission. Vegetative hyphal fusion is preceded by directed growth of the fusion hypha toward the receptor hypha and followed by a series of postfusion nuclear events, including mitosis of the apical nucleus of the fusion hypha, migration of a daughter nucleus into the receptor hypha, and degradation of the resident nucleus. These previously unreported patterns of nuclear dynamics in F. oxysporum could be intimately related to its pathogenic lifestyle.

  4. Hyphal ontogeny in Neurospora crassa: a model organism for all seasons [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Meritxell Riquelme

    2016-11-01

    Full Text Available Filamentous fungi have proven to be a better-suited model system than unicellular yeasts in analyses of cellular processes such as polarized growth, exocytosis, endocytosis, and cytoskeleton-based organelle traffic. For example, the filamentous fungus Neurospora crassa develops a variety of cellular forms. Studying the molecular basis of these forms has led to a better, yet incipient, understanding of polarized growth. Polarity factors as well as Rho GTPases, septins, and a localized delivery of vesicles are the central elements described so far that participate in the shift from isotropic to polarized growth. The growth of the cell wall by apical biosynthesis and remodeling of polysaccharide components is a key process in hyphal morphogenesis. The coordinated action of motor proteins and Rab GTPases mediates the vesicular journey along the hyphae toward the apex, where the exocyst mediates vesicle fusion with the plasma membrane. Cytoplasmic microtubules and actin microfilaments serve as tracks for the transport of vesicular carriers as well as organelles in the tubular cell, contributing to polarization. In addition to exocytosis, endocytosis is required to set and maintain the apical polarity of the cell. Here, we summarize some of the most recent breakthroughs in hyphal morphogenesis and apical growth in N. crassa and the emerging questions that we believe should be addressed.

  5. The yeast form of the fungus Candida albicans promotes persistence in the gut of gnotobiotic mice

    Science.gov (United States)

    Eckstein, Marie Therese

    2017-01-01

    Many microorganisms that cause systemic, life-threatening infections in humans reside as harmless commensals in our digestive tract. Yet little is known about the biology of these microbes in the gut. Here, we visualize the interface between the human commensal and pathogenic fungus Candida albicans and the intestine of mice, a surrogate host. Because the indigenous mouse microbiota restricts C. albicans settlement, we compared the patterns of colonization in the gut of germ free and antibiotic-treated conventionally raised mice. In contrast to the heterogeneous morphologies found in the latter, we establish that in germ free animals the fungus almost uniformly adopts the yeast cell form, a proxy of its commensal state. By screening a collection of C. albicans transcription regulator deletion mutants in gnotobiotic mice, we identify several genes previously unknown to contribute to in vivo fitness. We investigate three of these regulators—ZCF8, ZFU2 and TRY4—and show that indeed they favor the yeast form over other morphologies. Consistent with this finding, we demonstrate that genetically inducing non-yeast cell morphologies is detrimental to the fitness of C. albicans in the gut. Furthermore, the identified regulators promote adherence of the fungus to a surface covered with mucin and to mucus-producing intestinal epithelial cells. In agreement with this result, histology sections indicate that C. albicans dwells in the murine gut in close proximity to the mucus layer. Thus, our findings reveal a set of regulators that endows C. albicans with the ability to endure in the intestine through multiple mechanisms. PMID:29069103

  6. Plasticity of Candida albicans Biofilms

    Science.gov (United States)

    Daniels, Karla J.

    2016-01-01

    SUMMARY Candida albicans, the most pervasive fungal pathogen that colonizes humans, forms biofilms that are architecturally complex. They consist of a basal yeast cell polylayer and an upper region of hyphae encapsulated in extracellular matrix. However, biofilms formed in vitro vary as a result of the different conditions employed in models, the methods used to assess biofilm formation, strain differences, and, in a most dramatic fashion, the configuration of the mating type locus (MTL). Therefore, integrating data from different studies can lead to problems of interpretation if such variability is not taken into account. Here we review the conditions and factors that cause biofilm variation, with the goal of engendering awareness that more attention must be paid to the strains employed, the methods used to assess biofilm development, every aspect of the model employed, and the configuration of the MTL locus. We end by posing a set of questions that may be asked in comparing the results of different studies and developing protocols for new ones. This review should engender the notion that not all biofilms are created equal. PMID:27250770

  7. Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species

    Science.gov (United States)

    Whibley, Natasha; Gaffen, Sarah L.

    2015-01-01

    The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on C. albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions. PMID:26276374

  8. Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species.

    Science.gov (United States)

    Whibley, Natasha; Gaffen, Sarah L

    2015-11-01

    The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on Candida albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Immune response to Candida albicans Resposta imune a Candida albicans

    Directory of Open Access Journals (Sweden)

    Luis Carlos Jabur Gaziri

    2008-10-01

    Full Text Available Candida albicans causes infections of the skin, oral cavity and esophagus, gastrointestinal tract, vagina and vascular system. Most infections occur in immunocompromised hosts or debilitated patients. More than 90% of HIV positive patients suffer from mucosal candidiasis at least once in the course of this disease. The overall severity and chronicity of oral candidiasis in patients with AIDS are mainly attributed to the HIV-induced immune deficiency in the affected individuals, namely, the loss of T-helper cells and reduction in the number of CD4+ T lymphocytes. In mucosal colonization and systemic infections of mice by this fungus, Th1 cells mediate phagocyte-dependent protection, whose most important cytokines are IL-2, IFN-ã, TNF-á and IL-12. In contrast, production of inhibitory cytokines such as IL-4 and IL- 10 by Th2 cells are associated with disactivation of phagocytes and disease progression. Possibly, the growth of filamentous forms is better adapted to evade the cells of the immune system, whereas the yeast form may be the mode of proliferation in infected tissues. By the discriminative production of IL- 12 or IL-4 in response to the yeast or filamentous forms respectively, dendritic cells acquire the capacity of inducing the differentiation of CD4+ cells towards the Th1 or Th2 phenotypes. Candida albicans causa infecções na pele, cavidade oral e esôfago, trato gastrointestinal, vagina e sistema vascular de humanos. As infecções ocorrem em hospedeiros imunocomprometidos ou pacientes debilitados. Acima de 90% dos pacientes HIV+ sofrem de candidíase de mucosas ao menos uma vez no decorrer da doença. A severidade e cronicidade da candidíase oral em pacientes com AIDS são atribuídas, principalmente, à imunodeficiência induzida pelo HIV nos indivíduos afetados, a saber, perda de funções de célula T auxiliar e redução do número de linfócitos T CD4. Na colonização de mucosas e infecções sistêmicas de camundongos por

  10. Differential activity of Striga hermonthica seed germination stimulants and Gigaspora rosea hyphal branching factors in rice and their contribution to underground communication.

    Directory of Open Access Journals (Sweden)

    Catarina Cardoso

    Full Text Available Strigolactones (SLs trigger germination of parasitic plant seeds and hyphal branching of symbiotic arbuscular mycorrhizal (AM fungi. There is extensive structural variation in SLs and plants usually produce blends of different SLs. The structural variation among natural SLs has been shown to impact their biological activity as hyphal branching and parasitic plant seed germination stimulants. In this study, rice root exudates were fractioned by HPLC. The resulting fractions were analyzed by MRM-LC-MS to investigate the presence of SLs and tested using bioassays to assess their Striga hermonthica seed germination and Gigaspora rosea hyphal branching stimulatory activities. A substantial number of active fractions were revealed often with very different effect on seed germination and hyphal branching. Fractions containing (--orobanchol and ent-2'-epi-5-deoxystrigol contributed little to the induction of S. hermonthica seed germination but strongly stimulated AM fungal hyphal branching. Three SLs in one fraction, putative methoxy-5-deoxystrigol isomers, had moderate seed germination and hyphal branching inducing activity. Two fractions contained strong germination stimulants but displayed only modest hyphal branching activity. We provide evidence that these stimulants are likely SLs although no SL-representative masses could be detected using MRM-LC-MS. Our results show that seed germination and hyphal branching are induced to very different extents by the various SLs (or other stimulants present in rice root exudates. We propose that the development of rice varieties with different SL composition is a promising strategy to reduce parasitic plant infestation while maintaining symbiosis with AM fungi.

  11. Temporal Profile of Biofilm Formation, Gene Expression and Virulence Analysis in Candida albicans Strains.

    Science.gov (United States)

    de Barros, Patrícia Pimentel; Rossoni, Rodnei Dennis; De Camargo Ribeiro, Felipe; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

    2017-04-01

    The characterization of Candida albicans strains with different degrees of virulence became very useful to understand the mechanisms of fungal virulence. Then, the objective of this study was to assess and compare the temporal profiles of biofilms formation, gene expression of ALS1, ALS3, HWP1, BCR1, EFG1, TEC1, SAP5, PLB2 and LIP9 and virulence in Galleria mellonella of C. albicans ATCC18804 and a clinical sample isolated from an HIV-positive patient (CA60). Although the CFU/mL counting was higher in biofilms formed in vitro by ATCC strain, the temporal profile of the analysis of the transcripts of the C. albicans strains was elevated to Ca60 compared to strain ATCC, especially in the genes HWP1, ALS3, SAP5, PLB2 and LIP9 (up regulation). Ca60 was more pathogenic for G. mellonella in the survival assay (p = 0.0394) and hemocytes density (p = 0.0349), agreeing with upregulated genes that encode the expression of hyphae and hydrolase genes of Ca60. In conclusion, the C. albicans strains used in this study differ in the amount of biofilm formation, virulence in vivo and transcriptional profiles of genes analyzed that can change factors associated with colonization, proliferation and survival of C. albicans at different niches. SAP5 and HWP1 were the genes more expressed in the formation of biofilm in vitro.

  12. Farnesol inhibits translation to limit growth and filamentation in C. albicans and S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Nkechi E. Egbe

    2017-09-01

    Full Text Available Candida albicans is a polymorphic yeast where the capacity to switch between yeast and filamentous growth is critical for pathogenicity. Farnesol is a quorum-sensing sesquiterpene alcohol that, via regulation of specific signalling and transcription components, inhibits filamentous growth in C. albicans. Here we show that farnesol also inhibits translation at the initiation step in both C. albicans and S. cerevisiae. In contrast to fusel alcohols, that target the eukaryotic initiation factor 2B (eIF2B, farnesol affects the interaction of the mRNA with the small ribosomal subunit leading to reduced levels of the 48S preinitiation ribosomal complex in S. cerevisiae. Therefore, farnesol targets a different step in the translation pathway than fusel alcohols to elicit a completely opposite physiological outcome by negating filamentous growth.

  13. Candida albicans induces pro-inflammatory and anti-apoptotic signals in macrophages as revealed by quantitative proteomics and phosphoproteomics

    DEFF Research Database (Denmark)

    Reales-Calderón, Jose Antonio; Sylvester, Marc; Strijbis, Karin

    2013-01-01

    Macrophages play a pivotal role in the prevention of Candida albicans infections. Yeast recognition and phagocytosis by macrophages is mediated by Pattern Recognition Receptors (PRRs) that initiate downstream signal transduction cascades by protein phosphorylation and dephosphorylation. We exposed...... RAW 264.7 macrophages to C. albicans for 3h and used SILAC to quantify macrophage proteins and phosphoproteins by mass spectrometry to study the effects of infection. We identified 53 macrophage up-regulated proteins and 15 less abundant in the presence of C. albicans out of a total of 2071 identified...... of apoptotic markers revealed that anti-apoptotic signals prevailed during the interaction of the yeast. Our proteomics study suggests that besides inflammation, apoptosis is a central pathway in the immune defense against C. albicans infection....

  14. Influência de Lactobacillus rhamnosus na patogenicidade e na expressão de genes de virulência de Candida albicans: estudo in vitro e in vivo

    OpenAIRE

    Ribeiro, Felipe de Camargo [UNESP

    2015-01-01

    The high incidence of candidiasis caused by Candida albicans and the adaptability of this species, as well as resistance to antifungal drive the development of research on alternative therapies to control this infection. The aim of this study was to evaluate the influence of Lactobacillus rhamnosus and products of their metabolism against C. albicans, evaluating the pathogenicity and the expression of genes that regulate the formation of C. albicans biofilms in vitro and in vivo in invertebra...

  15. Urinary tract infections and Candida albicans.

    Science.gov (United States)

    Behzadi, Payam; Behzadi, Elham; Ranjbar, Reza

    2015-01-01

    Urinary tract candidiasis is known as the most frequent nosocomial fungal infection worldwide. Candida albicans is the most common cause of nosocomial fungal urinary tract infections; however, a rapid change in the distribution of Candida species is undergoing. Simultaneously, the increase of urinary tract candidiasis has led to the appearance of antifungal resistant Candida species. In this review, we have an in depth look into Candida albicans uropathogenesis and distribution of the three most frequent Candida species contributing to urinary tract candidiasis in different countries around the world. For writing this review, Google Scholar -a scholarly search engine- (http://scholar.google.com/) and PubMed database (http://www.ncbi.nlm.nih.gov/pubmed/) were used. The most recently published original articles and reviews of literature relating to the first three Candida species causing urinary tract infections in different countries and the pathogenicity of Candida albicans were selected and studied. Although some studies show rapid changes in the uropathogenesis of Candida species causing urinary tract infections in some countries, Candida albicans is still the most important cause of candidal urinary tract infections. Despite the ranking of Candida albicans as the dominant species for urinary tract candidiasis, specific changes have occurred in some countries. At this time, it is important to continue the surveillance related to Candida species causing urinary tract infections to prevent, control and treat urinary tract candidiasis in future.

  16. Characteristics of experimental Candida albicans infection of the central nervous system in rabbits.

    Science.gov (United States)

    Jafari, H S; Sáez-Llorens, X; Grimprel, E; Argyle, J C; Olsen, K D; McCracken, G H

    1991-08-01

    Different concentrations (10(7), 10(5), 10(3) cfu/ml) of Candida albicans were injected intracisternally in rabbits. The highest inoculum was fatal within 14 h in all animals. In recipients of 10(5) and 10(3) cfu/ml inocula, the mean +/- SD peak cerebrospinal fluid (CSF) tumor necrosis factor-alpha (TNF alpha) concentrations were 1.6 +/- 2.42 and 0.3 +/- 0.59 ng/ml, respectively, at 6 h; the mean +/- SD CSF leukocyte and protein concentrations were 6291 +/- 6515 and 453 +/- 674 cells/mm3 (at 24 h) and 118 +/- 90 and 109 +/- 122 mg/dl (at 12 and 24 h), respectively. At 6-10 days after inoculation, a second peak of TNF alpha activity was accompanied by increased CSF inflammation. Mortality in the 10(5) and 10(3) cfu/ml inoculum groups was 56% and 22%, respectively. Fatal infection was associated with higher second CSF peak TNF alpha and leukocyte concentrations and a larger proportion of culture-positive CSF samples. Histopathology revealed hyphal invasion, vasculitis, abscesses, and acute and chronic inflammatory infiltration of meninges and brain parenchyma. This model can be useful for evaluation of the pathogenesis and therapy of central nervous system fungal infections.

  17. Hyphal N transport by a vesicular-arbuscular mycorrhizal fungus associated with cucumber grown at three nitrogen levels

    DEFF Research Database (Denmark)

    Johansen, A.; Jakobsen, I.; Jensen, E.S.

    1994-01-01

    Cucumis sativus L. cv. Aminex (F1 hybrid) was grown alone or in symbiosis with Glomus intraradices Schenck and Smith in containers with two hyphal compartments (HC(A) and HC(B)) on either side of a root compartment (RC) separated by fine nylon mesh. Plants received a total of either 100, 200 or 4...

  18. Effect of the Ethyl Acetate Fraction of Eugenia uniflora on Proteins Global Expression during Morphogenesis in Candida albicans

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    Walicyranison P. Silva-Rocha

    2017-09-01

    Full Text Available Candida albicans is able to switch from yeast to hyphal growth and this is an essential step for tissue invasion and establishment of infection. Due to the limited drug arsenal used to treat fungal infections and the constant emergence of resistant strains, it is important to search for new therapeutic candidates. Therefore, this study aimed to investigate by proteomic analysis the role of a natural product (Eugenia uniflora in impairing hypha formation in C. albicans. We also tested the potential action of E. uniflora to prevent and treat oral candidiasis induced in a murine model of oral infection and the ability of polymorphonuclear neutrophils to phagocytize C. albicans cells treated with the ethyl acetate fraction of the extract. We found that this fraction greatly reduced hypha formation after morphogenesis induction in the presence of serum. Besides, several proteins were differentially expressed in cells treated with the fraction. Surprisingly, the ethyl acetate fraction significantly reduced phagocytosis in C. albicans (Mean 120.36 ± 36.71 yeasts/100 PMNs vs. 44.68 ± 19.84 yeasts/100 PMNs. Oral candidiasis was attenuated when C. albicans cells were either pre-incubated in the presence of E. uniflora or when the fraction was applied to the surface of the oral cavity after infection. These results were consistent with the reduction in CFU counts (2.36 vs. 1.85 Log10 CFU/ml and attenuation of tissue damage observed with histopathological analysis of animals belonging to treated group. We also observed shorter true hyphae by direct examination and histopathological analysis, when cells were treated with the referred natural product. The E. uniflora ethyl acetate fraction was non-toxic to human cells. E. uniflora may act on essential proteins mainly related to cellular structure, reducing the capacity of filamentation and attenuating infection in a murine model, without causing any toxic effect on human cells, suggesting that it may be a

  19. Interplay between Candida albicans and the Mammalian Innate Host Defense

    Science.gov (United States)

    Cheng, Shih-Chin; Joosten, Leo A. B.; Kullberg, Bart-Jan

    2012-01-01

    Candida albicans is both the most common fungal commensal microorganism in healthy individuals and the major fungal pathogen causing high mortality in at-risk populations, especially immunocompromised patients. In this review, we summarize the interplay between the host innate system and C. albicans, ranging from how the host recognizes, responds, and clears C. albicans infection to how C. albicans evades, dampens, and escapes from host innate immunity. PMID:22252867

  20. Changes in hyphal morphology due to chitosan treatment in some fungal species

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    Enio Nazaré de Oliveira Junior

    2012-10-01

    Full Text Available In this work, changes in the hyphal morphology due to chitosan treatment in some fungal species were studied. Scanning electron microscope (SEM observations revealed that chitosans with molar fraction of acetyl groups (F A 0.16 and 0.18 and degree of polymerization (DP 1,089 and 1,242 had a direct effect on the morphology of the chitosan-treated fungi, reflecting its potential for causing a delay in the growth of Alternaria alternata (500 µg × mL-1, Botrytis cinerea (1,000 µg × mL-1, Penicillium expansum (1,000 µg × mL-1 and Rhizopus stolonifer (500 µg × mL-1. Mycelial aggregation and structural changes such as excessive branching, swelling of the cell wall and hyphae size reduction were observed in the micrographs.

  1. Mycosynthesis of Silver Nanoparticles from Candida albicans and its ...

    African Journals Online (AJOL)

    Purpose: To produce and characterize silver nanoparticles using Candida albicans and evaluate its antibacterial properties. Methods: Extracellular silver nanoparticles were biosynthesized using C. albicans. The biomass obtained from cultures of C. albicans was used to synthesize silver nanoparticles in 1.5 mM silver ...

  2. 17β-Estradiol inhibits estrogen binding protein-mediated hypha formation in Candida albicans.

    Science.gov (United States)

    Kurakado, Sanae; Kurogane, Rie; Sugita, Takashi

    2017-08-01

    Candida albicans is one of the most prevalent and clinically important fungal pathogens. The ability to change form depending on environmental stress is an important microbial virulence factor. A survey of compounds that inhibit this morphological change identified various steroids, including 17β-estradiol. Interestingly, C. albicans has proteins capable of binding to steroids, including estrogen binding protein (Ebp1). Estrogens regulate cell differentiation and proliferation in humans through estrogen receptor proteins. To determine whether EBP1 regulates a virulence factor, we investigated the effect of 17β-estradiol on the morphological transition of C. albicans using an ebp1 deletion mutant. Treatment with 10 μg/mL of 17β-estradiol inhibited hypha formation, whereas its effect on the ebp1 deletion mutant was decreased compared to that on the wild-type and revertant strains. These data suggest a new pathway for the yeast-to-hypha transition via EBP1 in C. albicans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Comparative antifungal susceptibility analysis of Candida albicans versus non-albicans Candida corneal isolates.

    Science.gov (United States)

    Spierer, Oriel; Dugar, Jyoti; Miller, Darlene; OʼBrien, Terrence P

    2015-05-01

    To compare the in vitro activity of topical amphotericin B (AMB), natamycin, voriconazole, and fluconazole against human corneal isolates of Candida sp. for guidance in the treatment of Candida keratitis. Sixty-eight Candida isolates (37 albicans and 31 non-albicans isolates) recovered from corneal scrapings submitted to rule out microbial keratitis, during the years 2005 to 2011, at the Bascom Palmer Eye Institute, were examined in this study. Corneal isolates were cultured on fungal agars for 48 hours. Each yeast isolate was dispensed into 4 microtiter wells, each containing 100 mL of commercial (natamycin 5%) or compounded (AMB 0.15%, voriconazole 1%, and fluconazole 0.2%) antifungal medications. A comparison of growth patterns was conducted. One hundred percent of the samples showed growth inhibition after treatment exposure with AMB or natamycin. The isolates treated with voriconazole demonstrated an 85% inhibition rate overall, with the Candida albicans samples showing a 77% inhibition rate and the non-albicans sp. a 93% inhibition rate. In the fluconazole group, there was only a 19.6% inhibition rate noted, with a 7.7% inhibition rate observed in the C. albicans group versus a 30% inhibition rate in the non-albicans group. AMB 0.2% and natamycin 5% have equal effectiveness and full inhibition against Candida keratitis isolates. Fluconazole 0.2% is not the drug of choice in both C. albicans and non-albicans keratitis. Voriconazole 1% may need a stronger concentration for higher effectiveness, but potentially may be helpful as a second agent in the treatment of Candida keratitis.

  4. Comparison of albicans vs. non-albicans candidemia in French intensive care units

    Science.gov (United States)

    2010-01-01

    Introduction Candidemia raises numerous therapeutic issues for intensive care physicians. Epidemiological data that could guide the choice of initial therapy are still required. This analysis sought to compare the characteristics of intensive care unit (ICU) patients with candidemia due to non-albicans Candida species with those of ICU patients with candidemia due to Candida albicans. Methods A prospective, observational, multicenter, French study was conducted from October 2005 to May 2006. Patients exhibiting candidemia developed during ICU stay and exclusively due either to one or more non-albicans Candida species or to C. albicans were selected. The data collected included patient characteristics on ICU admission and at the onset of candidemia. Results Among the 136 patients analyzed, 78 (57.4%) had candidemia caused by C. albicans. These patients had earlier onset of infection (11.1 ± 14.2 days after ICU admission vs. 17.4 ± 17.7, p = 0.02), higher severity scores on ICU admission (SOFA: 10.4 ± 4.7 vs. 8.6 ± 4.6, p = 0.03; SAPS II: 57.4 ± 22.8 vs. 48.7 ± 15.5, P = 0.015), and were less often neutropenic (2.6% vs. 12%, p = 0.04) than patients with candidemia due to non-albicans Candida species. Conclusions Although patients infected with Candida albicans differed from patients infected with non-albicans Candida species for a few characteristics, no clinical factor appeared pertinent enough to guide the choice of empirical antifungal therapy in ICU. PMID:20507569

  5. Antibiotic resistance in Candida albicans and Staphylococcus ...

    African Journals Online (AJOL)

    Nowadays, vaginal candidiasis and bacterial vaginosis are frequently encountered in medical practice and antibiotic resistance in implicated pathogens has not been reported in Dschang. This study sought to determine the antimicrobial susceptibility patterns of 198 isolates of Candida albicans and 300 strains of ...

  6. Undecylenic Acid Inhibits Morphogenesis of Candida albicans

    OpenAIRE

    McLain, Nealoo; Ascanio, Rhoda; Baker, Carol; Strohaver, Robert A.; Dolan, Joseph W.

    2000-01-01

    Resilient liners are frequently used to treat denture stomatitis, a condition often associated with Candida albicans infections. Of 10 liners tested, 2 were found to inhibit the switch from the yeast form to hyphae and a third was found to stimulate this switch. The inhibitor was determined to be undecylenic acid.

  7. Undecylenic acid inhibits morphogenesis of Candida albicans.

    Science.gov (United States)

    McLain, N; Ascanio, R; Baker, C; Strohaver, R A; Dolan, J W

    2000-10-01

    Resilient liners are frequently used to treat denture stomatitis, a condition often associated with Candida albicans infections. Of 10 liners tested, 2 were found to inhibit the switch from the yeast form to hyphae and a third was found to stimulate this switch. The inhibitor was determined to be undecylenic acid.

  8. A trypsin inhibitor from Tecoma stans leaves inhibits growth and promotes ATP depletion and lipid peroxidation in Candida albicans and Candida krusei

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    Leydianne Leite de Siqueira Patriota

    2016-04-01

    Full Text Available Tecoma stans (yellow elder has shown medicinal properties and antimicrobial activity. Previous reports on antifungal activity of T. stans preparations and presence of trypsin inhibitor activity from T. stans leaves stimulated the investigation reported here. In this work, we proceeded to the purification and characterization of a trypsin inhibitor (TesTI, which was investigated for anti-Candida activity. Finally, in order to determine the potential of TesTI as a new natural chemotherapeutic product, its cytotoxicity to human peripheral blood mononuclear cells (PBMCs was evaluated. TesTI was isolated from saline extract by ammonium sulphate fractionation followed by ion exchange and gel filtration chromatographies. Antifungal activity was evaluated by determining the minimal inhibitory (MIC and fungicide (MFC concentrations using fungal cultures containing only yeast form or both yeast and hyphal forms. Candida cells treated with TesTI were evaluated for intracellular ATP levels and lipid peroxidation. Cytotoxicity of TesTI to PBMCs was evaluated by MTT assay. TesTI (39.8 kDa, pI 3.41, Ki 43 nM inhibited similarly the growth of both C. albicans and C. krusei culture types at MIC of 100 µg/mL. The MFCs were 200 µg/mL for C. albicans and C. krusei. Time-response curves revealed that TesTI (at MIC was more effective at inhibiting the replication of C. albicans cells. At MIC, TesTI promoted reduction of ATP levels and lipid peroxidation in the Candida cells, being not cytotoxic to PBMCs. In conclusion, TesTI is an antifungal agent against C. albicans and C. krusei, without toxicity to human cells.

  9. Antimicrobial effect of farnesol, a Candida albicans quorum sensing molecule, on Paracoccidioides brasiliensis growth and morphogenesis

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    Silva-Pereira Ildinete

    2009-04-01

    Full Text Available Abstract Background Farnesol is a sesquiterpene alcohol produced by many organisms, and also found in several essential oils. Its role as a quorum sensing molecule and as a virulence factor of Candida albicans has been well described. Studies revealed that farnesol affect the growth of a number of bacteria and fungi, pointing to a potential role as an antimicrobial agent. Methods Growth assays of Paracoccidioides brasiliensis cells incubated in the presence of different concentrations of farnesol were performed by measuring the optical density of the cultures. The viability of fungal cells was determined by MTT assay and by counting the colony forming units, after each farnesol treatment. The effects of farnesol on P. brasiliensis dimorphism were also evaluated by optical microscopy. The ultrastructural morphology of farnesol-treated P. brasiliensis yeast cells was evaluated by transmission and scanning electron microscopy. Results In this study, the effects of farnesol on Paracoccidioides brasiliensis growth and dimorphism were described. Concentrations of this isoprenoid ranging from 25 to 300 μM strongly inhibited P. brasiliensis growth. We have estimated that the MIC of farnesol for P. brasiliensis is 25 μM, while the MLC is around 30 μM. When employing levels which don't compromise cell viability (5 to 15 μM, it was shown that farnesol also affected the morphogenesis of this fungus. We observed about 60% of inhibition in hyphal development following P. brasiliensis yeast cells treatment with 15 μM of farnesol for 48 h. At these farnesol concentrations we also observed a significant hyphal shortening. Electron microscopy experiments showed that, despite of a remaining intact cell wall, P. brasiliensis cells treated with farnesol concentrations above 25 μM exhibited a fully cytoplasmic degeneration. Conclusion Our data indicate that farnesol acts as a potent antimicrobial agent against P. brasiliensis. The fungicide activity of farnesol

  10. Hyphal healing mechanism in the arbuscular mycorrhizal fungi Scutellospora reticulata and Glomus clarum differs in response to severe physical stress.

    Science.gov (United States)

    de la Providencia, Ivan Enrique; Fernández, Félix; Declerck, Stéphane

    2007-03-01

    The hyphal healing mechanism (HHM) has been shown to differ between Gigasporaceae and Glomeraceae. However, this process has not been considered under (severe) physical stress conditions. Scutellospora reticulata and Glomus clarum strains were cultured monoxenically. The impact of long distance separating cut extremities of hyphae and of multiple injuries within hyphae on the HHM was monitored. For long distances (>5000 microm) separating cut extremities, hyphae healing was observed in half the cases in S. reticulata and was absent in G. clarum. For multiple-injured hyphae, the HHM was always oriented towards the complete recovery of hyphae integrity in S. reticulata, while in G. clarum, the growing hyphal tips (GHTs) could indifferently reconnect cut sections, by-pass cut sections or develop into the environment. Hyphae behaviour under severe physical stress clearly differentiated S. reticulata from G. clarum, suggesting that both fungi have developed different strategies for colony growth to survive under adverse conditions.

  11. Occurrence of endospores within conidia and hyphal cells of morphologically atypical isolates of Ophiostoma guerci (Georg. Nannf.

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    Krystyna Przybył

    2014-08-01

    Full Text Available Ultrastructural observations of two Ophiostoma querci isolates presented in this paper showed endospores within hyphal cells and Sporothrix conidia. The endospores were apparently included in a matrix of an electron transparent material or were associated with unidentified granules scattered throught cytoplasm of enclosing cells. The endospores may be liberated by breakdown of the enclosing cell. When free they were observed giving rise to hyphae.

  12. Estradiol impairs the Th17 immune response against Candida albicans.

    Science.gov (United States)

    Relloso, Miguel; Aragoneses-Fenoll, Laura; Lasarte, Sandra; Bourgeois, Christelle; Romera, Gema; Kuchler, Karl; Corbí, Angel L; Muñoz-Fernández, M Angeles; Nombela, César; Rodríguez-Fernández, José L; Diez-Orejas, Rosalia

    2012-01-01

    Candida albicans is a commensal opportunistic pathogen that is also a member of gastrointestinal and reproductive tract microbiota. Exogenous factors, such as oral contraceptives, hormone replacement therapy, and estradiol, may affect susceptibility to Candida infection, although the mechanisms involved in this process have not been elucidated. We used a systemic candidiasis model to investigate how estradiol confers susceptibility to infection. We report that estradiol increases mouse susceptibility to systemic candidiasis, as in vivo and ex vivo estradiol-treated DCs were less efficient at up-regulating antigen-presenting machinery, pathogen killing, migration, IL-23 production, and triggering of the Th17 immune response. Based on these results, we propose that estradiol impairs DC function, thus explaining the increased susceptibility to infection during estrus.

  13. Possible involvement of hyphal phosphatase in phosphate efflux from intraradical hyphae isolated from mycorrhizal roots colonized by Gigaspora margarita.

    Science.gov (United States)

    Kojima, Tomoko; Saito, Masanori

    2004-06-01

    We developed a method for separating physiologically active intraradical hyphae of arbuscular mycorrhizal (AM) fungi from mycorrhizal roots, allowing the hyphae to be used for physiological and biochemical experiments. In the present study, the phosphate efflux from the intraradical hyphae in vitro was examined in relation to hyphal phosphatase activity. Onion seedlings (Allium cepa) were planted in the soil inoculated with Gigaspora margarita. Six weeks after transplanting, the intraradical hyphae were isolated from the mycorrhizal roots using plant cell-wall digestion enzymes. The hyphae were incubated briefly at 25 degrees C in a buffer solution (50 mM Tris/HCl, pH 7.4), then incubated for 2 h and gently shaken with various inhibitors. Phosphate efflux, the amount of phosphate released to the buffer, was analysed by EnzChek phosphate assay kit. Hyphal phosphatase activity was stained histochemically and the proportion of phosphatase-active arbuscules was examined for each inhibitor. Phosphate effluxes were to some degree reduced by all inhibitors used, while the phosphatase inhibitor, BeSO4, greatly reduced the efflux. The degree of inhibition in the arbuscular phosphatase by each chemical was closely correlated to the decrease in the phosphate efflux. These results suggest that hyphal phosphatase may be partially involved in the phosphate efflux process from intraradical hyphae.

  14. Tailoring fungal morphology of Aspergillus niger MYA 135 by altering the hyphal morphology and the conidia adhesion capacity: biotechnological applications.

    Science.gov (United States)

    Colin, Verónica Leticia; Baigorí, Mario Domingo; Pera, Licia María

    2013-05-20

    Current problems of filamentous fungi fermentations and their further successful developments as microbial cell factories are dependent on control fungal morphology. In this connection, this work explored new experimental procedures in order to quantitatively check the potential of some culture conditions to induce a determined fungal morphology by altering both hyphal morphology and conidia adhesion capacity. The capacity of environmental conditions to modify hyphal morphology was evaluated by examining the influence of some culture conditions on the cell wall lytic potential of Aspergillus niger MYA 135. The relative value of the cell wall lytic potential was determined by measuring a cell wall lytic enzyme activity such as the mycelium-bound β-N-acetyl-D-glucosaminidase (Mb-NAGase). On the other hand, the quantitative value of conidia adhesion was considered as an index of its aggregation capacity. Concerning microscopic morphology, a highly negative correlation between the hyphal growth unit length (lHGU) and the specific Mb-NAGase activity was found (r = -0.915, P morphology, a low conidia adhesion capacity was followed by a dispersed mycelial growth. In fact, this study showed that conidia adhesion units per ml equal to or higher than 0.50 were necessary to afford pellets formation. In addition, it was also observed that once the pellet was formed the lHGU had an important influence on its final diameter. Finally, the biotechnological significance of such results was discussed as well.

  15. Comparison of the hemolytic activity between C. albicans and non-albicans Candida species

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    Rodnei Dennis Rossoni

    2013-12-01

    Full Text Available The ability to produce enzymes, such as hemolysins, is an important virulence factor for the genus Candida.The objective of this study was to compare the hemolytic activity between C. albicansand non-albicans Candida species. Fifty strains of Candida species, isolated from the oral cavity of patients infected with HIV were studied. The isolates included the following species: C. albicans, C. dubliniensis, C. glabrata, C. tropicalis, C. krusei, C. parapsilosis, C. dubliniensis, C. norvegensis, C. lusitaniae, and C. guilliermondii. Hemolysin production was evaluated on Sabouraud dextrose agar containing chloramphenicol, blood, and glucose. A loop-full of pure Candidaculture was spot-inoculated onto plates and incubated at 37ºC for 24 h in a 5% CO2 atmosphere. Hemolytic activity was defined as the formation of a translucent halo around the colonies. All C. albicansstrains that were studied produced hemolysins. Among the non-albicans Candidaspecies, 86% exhibited hemolytic activity. Only C. guilliermondiiand some C. parapsilosis isolates were negative for this enzyme. In conclusion, most non-albicans Candidaspecies had a similar ability to produce hemolysins when compared to C. albicans.

  16. Neurospora COP9 signalosome integrity plays major roles for hyphal growth, conidial development, and circadian function.

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    Zhipeng Zhou

    Full Text Available The COP9 signalosome (CSN is a highly conserved multifunctional complex that has two major biochemical roles: cleaving NEDD8 from cullin proteins and maintaining the stability of CRL components. We used mutation analysis to confirm that the JAMM domain of the CSN-5 subunit is responsible for NEDD8 cleavage from cullin proteins in Neurospora crassa. Point mutations of key residues in the metal-binding motif (EX(nHXHX(10D of the CSN-5 JAMM domain disrupted CSN deneddylation activity without interfering with assembly of the CSN complex or interactions between CSN and cullin proteins. Surprisingly, CSN-5 with a mutated JAMM domain partially rescued the phenotypic defects observed in a csn-5 mutant. We found that, even without its deneddylation activity, the CSN can partially maintain the stability of the SCF(FWD-1 complex and partially restore the degradation of the circadian clock protein FREQUENCY (FRQ in vivo. Furthermore, we showed that CSN containing mutant CSN-5 efficiently prevents degradation of the substrate receptors of CRLs. Finally, we found that deletion of the CAND1 ortholog in N. crassa had little effect on the conidiation circadian rhythm. Our results suggest that CSN integrity plays major roles in hyphal growth, conidial development, and circadian function in N. crassa.

  17. Hyphal responses of Neurospora crassa to micron-sized beads with functional chemical surface groups

    Science.gov (United States)

    Held, Marie; Edwards, Clive; Nicolau, Dan V.

    2011-02-01

    Filamentous fungi include serious plant and animal pathogens that explore their environment efficiently in order to penetrate the host. This environment is physically and chemically heterogeneous and the fungi rely on specific physical and chemical signals to find the optimal point/s of attack. This study presents a methodology to introduce distinct structures with dimensions similar to the hyphal diameter and specific chemical surface groups into a controllable environment in order to study the fungal response. We introduced 3.3 μm polystyrene beads covered with Epoxy surface groups into microfluidic channels made from PDMS by rapid replica molding. The experimental setup resulted in different areas with low and high densities of beads as well as densely packed patches. The observations of the fungus exploring the areas long-term showed that the growth parameters were altered significantly, compared with the values measured on agar. The fungus responded to both, the physical and chemical parameters of the beads, including temporary directional changes, increased branching angles, decreased branching distances, decreased apical extension velocities and occasional cell wall lysis. The wealth and magnitude of the observed responses indicates that the microfluidic structures provide a powerful platform for the investigation of micron-sized features on filamentous fungi.

  18. Development of DNA probes for Candida albicans

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, L.L.; Hudson, J.B.

    1988-07-01

    An attempt was made to produce DNA probes that could be used as a rapid and efficient means of detecting candidiasis (invasive Candida infection) in immunocompromised patients. Whole DNA from Candida albicans was digested with restriction endonuclease, and the resulting fragments were randomly cloned into a plasmid vector. Several recombinant plasmids were evaluated for cross-hybridization to various other Candida species, other fungal DNAs, and to nonfungal DNAs. Cross reactions were observed between the probes and different yeasts, but none with unrelated DNAs. Some recombinants were genus-specific, and two of these were applied to the analysis of C. albicans growth curves. It became evident that, although both /sup 32/P- and biotin-labelled probes could be made quite sensitive, a possible limitation in their diagnostic potential was the poor liberation of Candida DNA from cells. Thus, better methods of treatment of clinical specimens will be required before such probes will be useful in routine diagnosis.

  19. Development of DNA probes for Candida albicans

    International Nuclear Information System (INIS)

    Cheung, L.L.; Hudson, J.B.

    1988-01-01

    An attempt was made to produce DNA probes that could be used as a rapid and efficient means of detecting candidiasis (invasive Candida infection) in immunocompromised patients. Whole DNA from Candida albicans was digested with restriction endonuclease, and the resulting fragments were randomly cloned into a plasmid vector. Several recombinant plasmids were evaluated for cross-hybridization to various other Candida species, other fungal DNAs, and to nonfungal DNAs. Cross reactions were observed between the probes and different yeasts, but none with unrelated DNAs. Some recombinants were genus-specific, and two of these were applied to the analysis of C. albicans growth curves. It became evident that, although both 32 P- and biotin-labelled probes could be made quite sensitive, a possible limitation in their diagnostic potential was the poor liberation of Candida DNA from cells. Thus, better methods of treatment of clinical specimens will be required before such probes will be useful in routine diagnosis

  20. Candida albicans isolates from a Malaysian hospital exhibit more potent phospholipase and haemolysin activities than non-albicans Candida isolates.

    Science.gov (United States)

    Chin, V K; Foong, K J; Maha, A; Rusliza, B; Norhafizah, M; Ng, K P; Chong, P P

    2013-12-01

    This study was aimed at determining the phospholipase and haemolysin activity of Candida isolates in Malaysia. A total of 37 Candida clinical isolates representing seven species, Candida albicans (12), Candida tropicalis (8), Candida glabrata (4), Candida parapsilosis (1), Candida krusei (4), Candida orthopsilosis (1) and Candida rugosa (7) were tested. In vitro phospholipase activity was determined by using egg yolk plate assay whereas in vitro haemolysin activity was tested by using blood plate assay on sheep blood Sabouraud's dextrose agar (SDA) enriched with glucose. Phospholipase activity was detected in 75% (9 out of 12) of the C. albicans isolates. Among the 25 non- C. albicans Candida isolates, phospholipase activity was detected in only 24% of these isolates. The phospholipase activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.002). Haemolysin activity was detected in 100% of the C. albicans, C. tropicalis, C. glabrata, C. krusei, C. parapsilosis, and C. orthopsilosis isolates while 75% of the C. krusei isolates and 12.3% of the C. rugosa isolates showed haemolysin activity. The haemolytic activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.0001).The findings in this study indicate that C. albicans isolates in Malaysia may possess greater virulence potential than the non-albicans species.

  1. Candida albicans versus Candida dubliniensis: Why Is C. albicans More Pathogenic?

    LENUS (Irish Health Repository)

    Moran, Gary P

    2012-01-01

    Candida albicans and Candida dubliniensis are highly related pathogenic yeast species. However, C. albicans is far more prevalent in human infection and has been shown to be more pathogenic in a wide range of infection models. Comparison of the genomes of the two species has revealed that they are very similar although there are some significant differences, largely due to the expansion of virulence-related gene families (e.g., ALS and SAP) in C. albicans, and increased levels of pseudogenisation in C. dubliniensis. Comparative global gene expression analyses have also been used to investigate differences in the ability of the two species to tolerate environmental stress and to produce hyphae, two traits that are likely to play a role in the lower virulence of C. dubliniensis. Taken together, these data suggest that C. dubliniensis is in the process of undergoing reductive evolution and may have become adapted for growth in a specialized anatomic niche.

  2. Candida albicans Adherence to Glass Ionomer Restorative Dental Material

    OpenAIRE

    Lawaf, Shirin; Azizi, Arash

    2009-01-01

    Background and aims. It is believed that adherence of Candida albicans to oral surfaces is a critical event in the colonization and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable information about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little information available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investiga...

  3. 1,4-Naphthoquinone derivatives potently suppress Candida albicans growth, inhibit formation of hyphae and show no toxicity toward zebrafish embryos.

    Science.gov (United States)

    Janeczko, Monika; Kubiński, Konrad; Martyna, Aleksandra; Muzyczka, Angelika; Boguszewska-Czubara, Anna; Czernik, Sławomir; Tokarska-Rodak, Małgorzata; Chwedczuk, Marta; Demchuk, Oleg M; Golczyk, Hieronim; Masłyk, Maciej

    2018-04-01

    In this study, we applied various assays to find new activities of 1,4-naphthoquinone derivatives for potential anti-Candida albicans applications. These assays determined (a) the antimicrobial effect on growth/cell multiplication in fungal cultures, (b) the effect on formation of hyphae and biofilm, (c) the influence on cell membrane integrity, (d) the effect on cell morphology using atomic force microscopy, and (e) toxicity against zebrafish embryos. We have demonstrated the activity of these compounds against different Candida species and clinical isolates of C. albicans. 1,4-Naphthoquinones significantly affected fungal strains at 8-250 mg l -1 of MIC. Interestingly, at concentrations below MICs, the chemicals showed effectiveness in inhibition of hyphal formation and cell aggregation in Candida. Of note, atomic force microscopy (AFM) analysis revealed an influence of the compounds on cell morphological properties. However, at low concentrations (0.8-31.2 mg l -1 ), it did not exert any evident toxic effects on zebrafish embryos. Our research has evidenced the effectiveness of 1,4-naphthoquinones as potential anti-Candida agents.

  4. PKA activity is essential for relieving the suppression of hyphal growth and appressorium formation by MoSfl1 in Magnaporthe oryzae.

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    Yang Li

    2017-08-01

    Full Text Available In the rice blast fungus Magnaporthe oryzae, the cAMP-PKA pathway regulates surface recognition, appressorium turgor generation, and invasive growth. However, deletion of CPKA failed to block appressorium formation and responses to exogenous cAMP. In this study, we generated and characterized the cpk2 and cpkA cpk2 mutants and spontaneous suppressors of cpkA cpk2 in M. oryzae. Our results demonstrate that CPKA and CPK2 have specific and overlapping functions, and PKA activity is essential for appressorium formation and plant infection. Unlike the single mutants, the cpkA cpk2 mutant was significantly reduced in growth and rarely produced conidia. It failed to form appressoria although the intracellular cAMP level and phosphorylation of Pmk1 MAP kinase were increased. The double mutant also was defective in plant penetration and Mps1 activation. Interestingly, it often produced fast-growing spontaneous suppressors that formed appressoria but were still non-pathogenic. Two suppressor strains of cpkA cpk2 had deletion and insertion mutations in the MoSFL1 transcription factor gene. Deletion of MoSFL1 or its C-terminal 93-aa (MoSFL1ΔCT was confirmed to suppress the defects of cpkA cpk2 in hyphal growth but not appressorium formation or pathogenesis. We also isolated 30 spontaneous suppressors of the cpkA cpk2 mutant in Fusarium graminearum and identified mutations in 29 of them in FgSFL1. Affinity purification and co-IP assays showed that this C-terminal region of MoSfl1 was essential for its interaction with the conserved Cyc8-Tup1 transcriptional co-repressor, which was reduced by cAMP treatment. Furthermore, the S211D mutation at the conserved PKA-phosphorylation site in MoSFL1 partially suppressed the defects of cpkA cpk2. Overall, our results indicate that PKA activity is essential for appressorium formation and proper activation of Pmk1 or Mps1 in M. oryzae, and phosphorylation of MoSfl1 by PKA relieves its interaction with the Cyc8-Tup1 co

  5. Candida albicans scavenges host zinc via Pra1 during endothelial invasion.

    Directory of Open Access Journals (Sweden)

    Francesco Citiulo

    Full Text Available The ability of pathogenic microorganisms to assimilate essential nutrients from their hosts is critical for pathogenesis. Here we report endothelial zinc sequestration by the major human fungal pathogen, Candida albicans. We hypothesised that, analogous to siderophore-mediated iron acquisition, C. albicans utilises an extracellular zinc scavenger for acquiring this essential metal. We postulated that such a "zincophore" system would consist of a secreted factor with zinc-binding properties, which can specifically reassociate with the fungal cell surface. In silico analysis of the C. albicans secretome for proteins with zinc binding motifs identified the pH-regulated antigen 1 (Pra1. Three-dimensional modelling of Pra1 indicated the presence of at least two zinc coordination sites. Indeed, recombinantly expressed Pra1 exhibited zinc binding properties in vitro. Deletion of PRA1 in C. albicans prevented fungal sequestration and utilisation of host zinc, and specifically blocked host cell damage in the absence of exogenous zinc. Phylogenetic analysis revealed that PRA1 arose in an ancient fungal lineage and developed synteny with ZRT1 (encoding a zinc transporter before divergence of the Ascomycota and Basidiomycota. Structural modelling indicated physical interaction between Pra1 and Zrt1 and we confirmed this experimentally by demonstrating that Zrt1 was essential for binding of soluble Pra1 to the cell surface of C. albicans. Therefore, we have identified a novel metal acquisition system consisting of a secreted zinc scavenger ("zincophore", which reassociates with the fungal cell. Furthermore, functional similarities with phylogenetically unrelated prokaryotic systems indicate that syntenic zinc acquisition loci have been independently selected during evolution.

  6. Interactions Between Candida albicans and Host Interações entre Candida albicans e Hospedeiro

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    Tatiane De Rossi

    2011-06-01

    Full Text Available Candida albicans can cause grave infections in patients who are immunocompromised by diseases, by surgery, or by immunesupresive therapy. The high levels of morbidity and mortality resulting from those infections in hospitalized patients show that C. albicans became a prominent human pathogen. Although the host immune system is the major factor balancing the transition from commensalisms to pathogenicity, several virulence attributes expressed by C. albicans, such as adhesion factors, phenotypic switching, dimorphic behavior, and secretion of hydrolytic enzymes, might contribute to the persistence of colonization as well as the development of symptomatic episodes. Host defense against candidiasis relies mainly on the ingestion and elimination of C. albicans by phagocytic cells, which present receptors Toll-like 4, dectin–1 associated to receptors Toll-like2 and mannose receptors. The cytokine IL-10 (IL-10 produced by phagocytes has a crucial role on susceptibility of host fungal infection, whereas IL-10 produced by regulatory T cells is mainly responsible by commensalisms. In contrast, productions of tumour necrosis factor - α (TNF-α, interleukin–1 β (lL-1 β, (IL-6 and (Il-12 provided protective cell–mediated immunity. The interferon-γ produced by natural killer and TH1 cells stimulates migration of phagocytes and major efficacy on destruction of fungi. In epithelial cells from mucosas the NOD-like receptors and defensins-β cytoplasmatic prevent the translocation of C. albicans from microbiota to tissues, which are modulated by IL-1 β, Il-17 and Il-22 cytokines. to pathogenicity, several virulence attributes expressed by C. albicans, such as adhesion factors, phenotypic switching, dimorphic behavior, and secretion of hydrolytic enzymes, might contribute to the persistence of colonization as well as the development of symptomatic episodes. Host defense against candidiasis relies mainly on the ingestion and elimination of C. albicans

  7. Baicalin prevents Candida albicans infections via increasing its apoptosis rate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shulong; Fu, Yingyuan, E-mail: yingyuanfu@126.com; Wu, Xiuzhen; Zhou, Zhixing; Xu, Jing; Zeng, Xiaoping; Kuang, Nanzhen; Zeng, Yurong

    2014-08-15

    Highlights: • Baicalin increases the ratio of the G0/G1 stages and C. albicans apoptosis. • Baicalin decreases the proliferation index of C. albicans. • Baicalin inhibits the biosynthesis of DNA, RNA and protein in C. albicans. • Baicalin depresses Succinate Dehydrogenase and Ca{sup 2+}–Mg{sup 2+} ATPase in C. albicans. • Baicalin increases the endocytic free Ca{sup 2+} concentration in C. albicans. - Abstract: Background: These experiments were employed to explore the mechanisms underlying baicalin action on Candida albicans. Methodology and principal findings: We detected the baicalin inhibition effects on three isotope-labeled precursors of {sup 3}H-UdR, {sup 3}H-TdR and {sup 3}H-leucine incorporation into C. albicans using the isotope incorporation technology. The activities of Succinate Dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca{sup 2+}–Mg{sup 2+} ATPase, cytosolic Ca{sup 2+} concentration, the cell cycle and apoptosis, as well as the ultrastructure of C.albicans were also tested. We found that baicalin inhibited {sup 3}H-UdR, {sup 3}H-TdR and {sup 3}H-leucine incorporation into C.albicans (P < 0.005). The activities of the SDH and Ca{sup 2+}–Mg{sup 2+} ATPase of C.albicans in baicalin groups were lower than those in control group (P < 0.05). Ca{sup 2+} concentrations of C. albicans in baicalin groups were much higher than those in control group (P < 0.05). The ratio of C.albicans at the G0/G1 stage increased in baicalin groups in dose dependent manner (P < 0.01). There were a significant differences in the apoptosis rate of C.albicans between baicalin and control groups (P < 0.01). After 12–48 h incubation with baicalin (1 mg/ml), C. albicans shown to be markedly damaged under transmission electron micrographs. Innovation and significance: Baicalin can increase the apoptosis rate of C. albicans. These effects of Baicalin may involved in its inhibiting the activities of the SDH and Ca{sup 2+}–Mg{sup 2+} ATPase, increasing

  8. Baicalin prevents Candida albicans infections via increasing its apoptosis rate

    International Nuclear Information System (INIS)

    Yang, Shulong; Fu, Yingyuan; Wu, Xiuzhen; Zhou, Zhixing; Xu, Jing; Zeng, Xiaoping; Kuang, Nanzhen; Zeng, Yurong

    2014-01-01

    Highlights: • Baicalin increases the ratio of the G0/G1 stages and C. albicans apoptosis. • Baicalin decreases the proliferation index of C. albicans. • Baicalin inhibits the biosynthesis of DNA, RNA and protein in C. albicans. • Baicalin depresses Succinate Dehydrogenase and Ca 2+ –Mg 2+ ATPase in C. albicans. • Baicalin increases the endocytic free Ca 2+ concentration in C. albicans. - Abstract: Background: These experiments were employed to explore the mechanisms underlying baicalin action on Candida albicans. Methodology and principal findings: We detected the baicalin inhibition effects on three isotope-labeled precursors of 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C. albicans using the isotope incorporation technology. The activities of Succinate Dehydrogenase (SDH), cytochrome oxidase (CCO) and Ca 2+ –Mg 2+ ATPase, cytosolic Ca 2+ concentration, the cell cycle and apoptosis, as well as the ultrastructure of C.albicans were also tested. We found that baicalin inhibited 3 H-UdR, 3 H-TdR and 3 H-leucine incorporation into C.albicans (P < 0.005). The activities of the SDH and Ca 2+ –Mg 2+ ATPase of C.albicans in baicalin groups were lower than those in control group (P < 0.05). Ca 2+ concentrations of C. albicans in baicalin groups were much higher than those in control group (P < 0.05). The ratio of C.albicans at the G0/G1 stage increased in baicalin groups in dose dependent manner (P < 0.01). There were a significant differences in the apoptosis rate of C.albicans between baicalin and control groups (P < 0.01). After 12–48 h incubation with baicalin (1 mg/ml), C. albicans shown to be markedly damaged under transmission electron micrographs. Innovation and significance: Baicalin can increase the apoptosis rate of C. albicans. These effects of Baicalin may involved in its inhibiting the activities of the SDH and Ca 2+ –Mg 2+ ATPase, increasing cytosolic Ca 2+ content and damaging the ultrastructure of C. albicans

  9. Candida albicans response to spaceflight (NASA STS-115)

    Data.gov (United States)

    National Aeronautics and Space Administration — This study presents the first global transcriptional profiling and phenotypic characterization of the major human opportunistic fungal pathogen Candida albicans...

  10. Crystal structure of the Candida albicans Kar3 kinesin motor domain fused to maltose-binding protein

    International Nuclear Information System (INIS)

    Delorme, Caroline; Joshi, Monika; Allingham, John S.

    2012-01-01

    Highlights: ► The Candida albicans Kar3 motor domain structure was solved as a maltose-binding protein fusion. ► The electrostatic surface and part of the ATPase pocket of the motor domain differs markedly from other kinesins. ► The MBP–Kar3 interface highlights a new site for intramolecular or intermolecular interactions. -- Abstract: In the human fungal pathogen Candida albicans, the Kinesin-14 motor protein Kar3 (CaKar3) is critical for normal mitotic division, nuclear fusion during mating, and morphogenic transition from the commensal yeast form to the virulent hyphal form. As a first step towards detailed characterization of this motor of potential medical significance, we have crystallized and determined the X-ray structure of the motor domain of CaKar3 as a maltose-binding protein (MBP) fusion. The structure shows strong conservation of overall motor domain topology to other Kar3 kinesins, but with some prominent differences in one of the motifs that compose the nucleotide-binding pocket and the surface charge distribution. The MBP and Kar3 modules are arranged such that MBP interacts with the Kar3 motor domain core at the same site where the neck linker of conventional kinesins docks during the “ATP state” of the mechanochemical cycle. This site differs from the Kar3 neck–core interface in the recent structure of the ScKar3Vik1 heterodimer. The position of MBP is also completely distinct from the Vik1 subunit in this complex. This may suggest that the site of MBP interaction on the CaKar3 motor domain provides an interface for the neck, or perhaps a partner subunit, at an intermediate state of its motile cycle that has not yet been observed for Kinesin-14 motors.

  11. Comparison of the clinical risk factors between Candida albicans and Candida non-albicans species for bloodstream infection.

    Science.gov (United States)

    Shigemura, Katsumi; Osawa, Kayo; Jikimoto, Takumi; Yoshida, Hiroyuki; Hayama, Brian; Ohji, Goh; Iwata, Kentaro; Fujisawa, Masato; Arakawa, Soichi

    2014-04-01

    The purpose of this study is to investigate the risk factors and susceptibilities to antifungal agents of Candida albicans and Candida non-albicans species (spp.) in candidemia cases in Kobe University Hospital. We investigated all consecutive patients with candida bloodstream infection (BSI) from 2008-2013 for whose full data were available for analyses, examining clinical factors such as gender, general complications, postoperative status or susceptibilities to antifungal agents. These factors were also compared between Candida albicans spp. and Candida non-albicans by univariate and multivariate analyses. Univariate analyses showed a significantly higher rate of Candida non-albicans species BSI patients cancer (odds ratio (OR) (95% confidence interval (CI))=2.29 (1.04-5.06) and P=0.040), chemotherapy (OR=4.35 (1.11-17.1) and P=0.035), fluconazole (FLCZ) resistance (OR=77.3 (4.51-1324) and P=0.003), and itraconazole (ITCZ) resistance (OR=15.6 (5.39-45.1) and PCandida albicans. Multivariate analyses demonstrated that Candida non-albicans spp. had significantly higher rate of chemotherapy (OR=4.44 (1.04-19.0) and P=0.045), FLCZ resistance (OR=5.87 (2.01-17.1) and P=0.001), and ITCZ resistance (OR=18.7(5.77-60.4) and PCandida albicans. In conclusion, this study revealed several risk factors for BSI with Candida albicans (underlying cardiovascular diseases and postoperative status) and Candida non-albicans spp. (cancer and chemotherapy), and demonstrated that Candida non-albicans spp. were more resistant to FLCZ and ITCZ than Candida albicans.

  12. Profiling of Candida albicans gene expression during intra-abdominal candidiasis identifies biologic processes involved in pathogenesis.

    Science.gov (United States)

    Cheng, Shaoji; Clancy, Cornelius J; Xu, Wenjie; Schneider, Frank; Hao, Binghua; Mitchell, Aaron P; Nguyen, M Hong

    2013-11-01

    The pathogenesis of intra-abdominal candidiasis is poorly understood. Mice were intraperitoneally infected with Candida albicans (1 × 10(6) colony-forming units) and sterile stool. nanoString assays were used to quantitate messenger RNA for 145 C. albicans genes within the peritoneal cavity at 48 hours. Within 6 hours after infection, mice developed peritonitis, characterized by high yeast burdens, neutrophil influx, and a pH of 7.9 within peritoneal fluid. Organ invasion by hyphae and early abscess formation were evident 6 and 24 hours after infection, respectively; abscesses resolved by day 14. nanoString assays revealed adhesion and responses to alkaline pH, osmolarity, and stress as biologic processes activated in the peritoneal cavity. Disruption of the highly-expressed gene RIM101, which encodes an alkaline-regulated transcription factor, did not impact cellular morphology but reduced both C. albicans burden during early peritonitis and C. albicans persistence within abscesses. RIM101 influenced expression of 49 genes during intra-abdominal candidiasis, including previously unidentified Rim101 targets. Overexpression of the RIM101-dependent gene SAP5, which encodes a secreted protease, restored the ability of a rim101 mutant to persist within abscesses. A mouse model of intra-abdominal candidiasis is valuable for studying pathogenesis and C. albicans gene expression. RIM101 contributes to persistence within intra-abdominal abscesses, at least in part through activation of SAP5.

  13. Anti-hyphal formation property of allicin in suppression of Aspergillus fumigatus growth

    Directory of Open Access Journals (Sweden)

    Sajali, N.

    2013-01-01

    Full Text Available Aims: The aim of this study was to examine whether allicin, a compound derived from fresh garlic, leads to growth inhibition and changes in the ultrastructure of the cell surface on medically important filamentous fungi, particularly Aspergillus fumigatus.Methodology and results: The minimum inhibitory concentration (MIC of allicin in A. fumigatus ATCC 36607 was determined by broth microdilution method according to the CLSI M38-A2 documents whereby the minimal fungicidal concentration (MFC was determined by plating suspensions from visibly clear wells onto Sabouraud dextrose agar (SDA. Morphological changes on cell surface were observed through scanning electron microscopy (SEM after 48 h incubation with allicin. In addition, time kill assay was conducted by incubating A. fumigatus at selected time points within 24 h period. Our finding indicated that the MIC and MFC for allicin were both 3.2 µg/mL. Quantitative data for optical density obtained through microplate reader indicated that p<0.05 at MIC value in comparison with untreated control. Observation of allicin-treated cells through SEM demonstrated complete abrogation of hyphae formation at 3.2 µg/mL and reduced mycelial growth at 1.6 µg/mL of allicin. This finding revealed anti-hyphal activity of allicin at 3.2 µg/mL. When A. fumigatus was incubated with 3.2 µg/mL allicin in the time course assay, the inhibitory effect of allicin was evident after 12 h incubation. Conclusion, significance and impact of study: Our finding strongly implied that allicin exerts its antifungal activity against A. fumigatus via inhibiting the fungal cell proliferation as well as hindering transformation of the conidia into hyphae. Thus, this study depicted potential antifungal property of allicin to be used as alternative therapy to alleviate invasive fungal infection caused by A. fumigatus.

  14. Cell wall carbohydrates content of pathogenic Candida albicans strain morphological forms.

    Science.gov (United States)

    Staniszewska, Monika; Bondaryk, Małgorzata; Rabczenko, Daniel; Smoleńska-Sym, Gabriela; Kurzatkowski, Wiesław

    2013-01-01

    The study evaluated the cell wall carbohydrates fraction in blastoconidia grown in YEPD medium at 30 degrees C and in the conglomerate of true hyphae grown in human serum at 37 degrees C. The clinical isolate obtained from a child with widespread C. albicans infection was used in the study. The cells were broken with glass beads, centrifuged to harvest the cell wall followed by subjection to TFA hydrolysis and in the result of that released monosaccharides were detected by HPAEC-PAD. Both, serum and temperature conditions (37 degrees C) affected germination process influencing the cell wall carbohydrates content when incubation in serum was prolonged from 1 to 18 h. The mannan content of blastoconidia was almost twofold higher compared to filamentous forms (149.25 +/- 299.24 vs 77.26 +/- 122.07). The glucan content was threefold lower in blastoconidia compared to hyphae (251.86 +/- 243.44 vs 755.81 +/- 1299.30). The chitin level was fourfold lower in blastoconidia compared to filaments (23.86 +/- 54.09 vs 106.29 +/- 170.12). The reason for the differences in the carbohydrates content may be related to type of morphology induced in different environmental conditions. Among tested carbohydrates, glucan appeared to be present in appreciably larger amounts in both tested morphological fractions. The ultrastructure of the blastoconidial cell wall revealed striking differences compared to the hyphae indicating the carbohydrates content alterations for wall assembly during hyphal growth at alkaline pH and temp. 37 degrees C. The study provided evidence for the relationship between morphogenesis, cell-cell adhesion induced by serum and changes in the level of carbohydrates content.

  15. Biofilm extracellular DNA enhances mixed species biofilms of Staphylococcus epidermidis and Candida albicans

    Science.gov (United States)

    2013-01-01

    Background Polymicrobial infections are responsible for significant mortality and morbidity in adults and children. Staphylococcus epidermidis and Candida albicans are the most frequent combination of organisms isolated from polymicrobial infections. Vascular indwelling catheters are sites for mixed species biofilm formation and pose a significant risk for polymicrobial infections. We hypothesized that enhancement of biofilms in a mixed species environment increases patient mortality and morbidity. Results Mixed species biofilms of S. epidermidis and C. albicans were evaluated in vitro and in a subcutaneous catheter infection model in vivo. Mixed species biofilms were enhanced compared to single species biofilms of either S. epidermidis or C. albicans. A mixed species environment increased catheter infection and increased dissemination of S. epidermidis in mice. Microarrays were used to explore differential gene expression of S. epidermidis in the mixed species biofilms. In mixed species biofilms, compared to single species S. epidermidis biofilms, 2.7% of S. epidermidis genes were upregulated and 6% were down regulated. Staphylococcal autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively. The role of biofilm extracellular DNA was investigated by quantitation and by evaluating the effects of DNAse in a concentration and time dependent manner. S. epidermidis specific eDNA was increased in mixed species biofilms and further confirmed by degradation with DNAse. Conclusions Mixed-species biofilms are enhanced and associated with increased S. epidermidis-specific eDNA in vitro and greater systemic dissemination of S. epidermidis in vivo. Down regulation of the lrg operon, a repressor of autolysis, associated with increased eDNA suggests a possible role for bacterial autolysis in mixed species biofilms. Enhancement and systemic dissemination of S. epidermidis may explain adverse outcomes after clinical polymicrobial infections of S

  16. TiO2 coatings via atomic layer deposition on polyurethane and polydimethylsiloxane substrates: Properties and effects on C. albicans growth and inactivation process

    Science.gov (United States)

    Pessoa, R. S.; dos Santos, V. P.; Cardoso, S. B.; Doria, A. C. O. C.; Figueira, F. R.; Rodrigues, B. V. M.; Testoni, G. E.; Fraga, M. A.; Marciano, F. R.; Lobo, A. O.; Maciel, H. S.

    2017-11-01

    Atomic layer deposition (ALD) surges as an attractive technology to deposit thin films on different substrates for many advanced biomedical applications. Herein titanium dioxide (TiO2) thin films were successful obtained on polyurethane (PU) and polydimethylsiloxane (PDMS) substrates using ALD. The effect of TiO2 films on Candida albicans growth and inactivation process were also systematic discussed. TiCl4 and H2O were used as precursors at 80 °C, while the reaction cycle number ranged from 500 to 2000. Several chemical, physical and physicochemical techniques were used to evaluate the growth kinetics, elemental composition, material structure, chemical bonds, contact angle, work of adhesion and surface morphology of the ALD TiO2 thin films grown on both substrates. For microbiological analyses, yeasts of standard strains of C. albicans were grown on non- and TiO2-coated substrates. Next, the antifungal and photocatalytic activities of the TiO2 were also investigated by counting the colony-forming units (CFU) before and after UV-light treatment. Chlorine-doped amorphous TiO2 films with varied thicknesses and Cl concentration ranging from 2 to 12% were obtained. In sum, the ALD TiO2 films suppressed the yeast-hyphal transition of C. albicans onto PU, however, a high adhesion of yeasts was observed. Conversely, for PDMS substrate, the yeast adhesion did not change, as observed in control. Comparatively to control, the TiO2-covered PDMS had a reduction in CFU up to 59.5% after UV treatment, while no modification was observed to TiO2-covered PU. These results pointed out that ALD chlorine-doped amorphous TiO2 films grown on biomedical polymeric surfaces may act as fungistatic materials. Furthermore, in case of contamination, these materials may also behave as antifungal materials under UV light exposure.

  17. UDP-glucose 4, 6-dehydratase activity plays an important role in maintaining cell wall integrity and virulence of Candida albicans.

    Directory of Open Access Journals (Sweden)

    Manimala Sen

    2011-11-01

    Full Text Available Candida albicans, a human fungal pathogen, undergoes morphogenetic changes that are associated with virulence. We report here that GAL102 in C. albicans encodes a homolog of dTDP-glucose 4,6-dehydratase, an enzyme that affects cell wall properties as well as virulence of many pathogenic bacteria. We found that GAL102 deletion leads to greater sensitivity to antifungal drugs and cell wall destabilizing agents like Calcofluor white and Congo red. The mutant also formed biofilms consisting mainly of hyphal cells that show less turgor. The NMR analysis of cell wall mannans of gal102 deletion strain revealed that a major constituent of mannan is missing and the phosphomannan component known to affect virulence is greatly reduced. We also observed that there was a substantial reduction in the expression of genes involved in biofilm formation but increase in the expression of genes encoding glycosylphosphatidylinositol-anchored proteins in the mutant. These, along with altered mannosylation of cell wall proteins together might be responsible for multiple phenotypes displayed by the mutant. Finally, the mutant was unable to grow in the presence of resident peritoneal macrophages and elicited a weak pro-inflammatory cytokine response in vitro. Similarly, this mutant elicited a poor serum pro-inflammatory cytokine response as judged by IFNγ and TNFα levels and showed reduced virulence in a mouse model of systemic candidiasis. Importantly, an Ala substitution for a conserved Lys residue in the active site motif YXXXK, that abrogates the enzyme activity also showed reduced virulence and increased filamentation similar to the gal102 deletion strain. Since inactivating the enzyme encoded by GAL102 makes the cells sensitive to antifungal drugs and reduces its virulence, it can serve as a potential drug target in combination therapies for C. albicans and related pathogens.

  18. Candida albicans osteomyelitis of the cervical spine

    International Nuclear Information System (INIS)

    Cha, Jang-Gyu; Hong, Hyun-Sook; Koh, Yoon-Woo; Kim, Hee-Kyung; Park, Jung-Mi

    2008-01-01

    Fungal osteomyelitis is a rare infection that usually develops in immunocompromised patients. Additionally, involvement of the cervical spine by Candida albicans is extremely rare; only three previous cases of Candida vertebral osteomyelitis have been reported in the literature. The diagnosis may be delayed due to nonspecific radiologic findings and a slow progression. We report the CT, MRI, bone scan, and PET-CT findings in a patient who developed Candida osteomyelitis, which was initially misdiagnosed as metastasis, at the atlas and axis following treatment for nasopharyngeal cancer. (orig.)

  19. Real-time PCR expression profiling of genes encoding potential virulence factors in Candida albicans biofilms: identification of model-dependent and -independent gene expression

    Directory of Open Access Journals (Sweden)

    Řičicová Markéta

    2010-04-01

    Full Text Available Abstract Background Candida albicans infections are often associated with biofilm formation. Previous work demonstrated that the expression of HWP1 (hyphal wall protein and of genes belonging to the ALS (agglutinin-like sequence, SAP (secreted aspartyl protease, PLB (phospholipase B and LIP (lipase gene families is associated with biofilm growth on mucosal surfaces. We investigated using real-time PCR whether genes encoding potential virulence factors are also highly expressed in biofilms associated with abiotic surfaces. For this, C. albicans biofilms were grown on silicone in microtiter plates (MTP or in the Centres for Disease Control (CDC reactor, on polyurethane in an in vivo subcutaneous catheter rat (SCR model, and on mucosal surfaces in the reconstituted human epithelium (RHE model. Results HWP1 and genes belonging to the ALS, SAP, PLB and LIP gene families were constitutively expressed in C. albicans biofilms. ALS1-5 were upregulated in all model systems, while ALS9 was mostly downregulated. ALS6 and HWP1 were overexpressed in all models except in the RHE and MTP, respectively. The expression levels of SAP1 were more pronounced in both in vitro models, while those of SAP2, SAP4 and SAP6 were higher in the in vivo model. Furthermore, SAP5 was highly upregulated in the in vivo and RHE models. For SAP9 and SAP10 similar gene expression levels were observed in all model systems. PLB genes were not considerably upregulated in biofilms, while LIP1-3, LIP5-7 and LIP9-10 were highly overexpressed in both in vitro models. Furthermore, an elevated lipase activity was detected in supernatans of biofilms grown in the MTP and RHE model. Conclusions Our findings show that HWP1 and most of the genes belonging to the ALS, SAP and LIP gene families are upregulated in C. albicans biofilms. Comparison of the fold expression between the various model systems revealed similar expression levels for some genes, while for others model-dependent expression

  20. Candida albicans Hap43 Domains Are Required under Iron Starvation but Not Excess

    Directory of Open Access Journals (Sweden)

    Volha Skrahina

    2017-12-01

    Full Text Available Iron availability is a central factor in infections, since iron is a critical micronutrient for all living organisms. The host employs both iron limitation and toxicity strategies to control microbial growth, and successful pathogens are able to tightly coordinate iron homeostasis in response to changing iron levels. As a commensal and opportunistic pathogen, Candida albicans copes with both iron deficiency and excess via the precise regulation of iron acquisition, consumption and storage. The C. albicans transcription factor Hap43 is known to be required for the iron starvation response, while specific domains of its ortholog, HapX, in Aspergillus fumigatus, were recently shown to regulate iron uptake and consumptions genes under both low and high iron levels. Therefore, we investigated the contribution of C. albicans Hap43 domains in response to changing iron levels. We found the C-terminus of Hap43 to be essential for the activation of iron uptake genes during iron starvation, whereas, in contrast to A. fumigatus, Hap43 was not required in mediating adaptation to iron resistance. These data indicate that the generally conserved metal acquisition systems in fungal pathogens can show individual adaptations to the host environment.

  1. Mass spectrometric analysis of the secretome of Candida albicans

    NARCIS (Netherlands)

    Sorgo, A.G.; Heilmann, C.J.; Dekker, H.L.; Brul, S.; de Koster, C.G.; Klis, F.M.

    2010-01-01

    The pathogenic fungus Candida albicans secretes a considerable number of hydrolases and other proteins. In-depth studies of the C. albicans secretome could thus provide new candidates for diagnostic markers and vaccine development. We compared various growth conditions differing in pH, temperature

  2. Sensitivity pattern of clinical isolates of Candida albicans from hiv ...

    African Journals Online (AJOL)

    This study was carried out to investigate the sensitivity pattern of clinical isolates of C. albicans from HIV/AIDS patients to combined P. grisea extract and tioconazole. Twenty isolates of C. albicans were obtained from high vaginal swab (HVS) from HIV/AIDS patients in Bishop Shanahan Hospital, Nsukka after their ...

  3. Antifungal drug susceptibility of Candida albicans | Bii | East African ...

    African Journals Online (AJOL)

    Objective: To determine the susceptibility of clinical isolates of Candida albicans and to establish the minimum inhibitory concentrations (MIC) to commonly used antifungal drugs. Design: Laboratory based experiment. Setting: Mbagathi District Hospital, Nairobi, Kenya. Subjects: Candida albicans isolated between 1998 ...

  4. Candida albicans adherence to glass ionomer restorative dental material

    Directory of Open Access Journals (Sweden)

    Shirin Lawaf

    2009-06-01

    Full Text Available Background and aims. It is believed that adherence of Candida albicans to oral surfaces is a critical event in the colonization and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable information about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little information available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investigate the degree of Candida albicans adherence to glass ionomer restorative material. Materials and methods. In this experimental study adherence of Candida albicans strains was studied with and without human whole saliva. First, glass ionomer fragments were prepared; then yeast cells were inoculated and incubated with different incubation times. After incubation, the fragments were removed from the wells and stained with 0.1% calcofluor white. Adhesion was quantified by counting the total number of cells at 40, 80 and 120 minutes. The analysis of variance and Student's test were used to assess the significance of differences between the means. Results. In the absence of saliva, the adherence of Candida albicans showed an increase, reaching a maximum at the end of the experiment (120 minutes. However, in the presence of saliva, the adherence of Candida albicans to glass ionomer significantly decreased. Conclusion. The presence of human whole saliva is an important factor in the adherence of Candida albicans to glass ionomer restorative material.

  5. Candida albicans Adherence to Glass Ionomer Restorative Dental Material.

    Science.gov (United States)

    Lawaf, Shirin; Azizi, Arash

    2009-01-01

    It is believed that adherence of Candida albicans to oral surfaces is a critical event in the coloni-zation and development of oral diseases such as candida-associated denture stomatitis. Although there is considerable infor-mation about the adherence of Candida albicans to buccal epithelial cells and prosthetic materials, there is very little infor-mation available about the adherence of Candida albicans to glass ionomer materials. The purpose of this study was to investigate the degree of Candida albicans adherence to glass ionomer restorative material. In this experimental study adherence of Candida albicans strains was studied with and without human whole saliva. First, glass ionomer fragments were prepared; then yeast cells were inoculated and incubated with differ-ent incubation times. After incubation, the fragments were removed from the wells and stained with 0.1% calcofluor white. Adhesion was quantified by counting the total number of cells at 40, 80 and 120 minutes. The analysis of variance and Stu-dent's test were used to assess the significance of differences between the means. In the absence of saliva, the adherence of Candida albicans showed an increase, reaching a maximum at the end of the experiment (120 minutes). However, in the presence of saliva, the adherence of Candida albicans to glass ionomer significantly decreased. The presence of human whole saliva is an important factor in the adherence of Candida albicans to glass ion-omer restorative material.

  6. Evaluation of Candida Albicans Biofilm Formation on Various Parts ...

    African Journals Online (AJOL)

    Evaluation of Candida Albicans Biofilm Formation on Various Parts of Implant Material Surfaces. ... In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, non-biological surfaces, such as dental materials. C. albicans adhesion to denture materials is widely ...

  7. Evaluation of Candida albicans biofilm formation on various dental ...

    African Journals Online (AJOL)

    This study compared the susceptibility of six dental restorative materials to Candida albicans adhesion. Materials and methods: Cylindrical samples of each material were made according to the manufacturers' instructions. The antifungal effect of the samples on C. albicans was determined with the disc-diffusion method.

  8. Emerging azole resistance among Candida albicans from clinical ...

    African Journals Online (AJOL)

    Candida albicans is one of the most frequently isolated yeasts in clinical laboratories and accounts for up to 80 % of the yeasts recovered from sites of infection. The study was set out to determine antifungal susceptibility of clinical isolates of Candida albicans and to establish the Minimum Inhibitory Concentrations (MIC) to ...

  9. Comparison of the adhesion ability of Candida albicans strains to ...

    African Journals Online (AJOL)

    The purpose of the present study is to investigate the ability of oral Candida albicans strains to adhere to Caco-2 and Hep-2 epithelial cells, to produce slime using Congo red and Safranin methods and to form a biofilm on polymethylmethacrylate. A total of 20 C. albicans strains were tested in the present work. The biofilm ...

  10. Acid production by oral strains of Candida albicans and Lactobacilli

    NARCIS (Netherlands)

    Klinke, T.; Kneist, S.; de Soet, J.J.; Kuhlisch, E.; Mauersberger, S.; Forster, A.; Klimm, W.

    2009-01-01

    Both Candida albicans and lactobacilli are common colonizers of carious lesions in children and adolescents. The purpose of this study is to compare the velocity of acid production between C. albicans and several Lactobacillus species at different pH levels and concentrations of glucose. Washed,

  11. IL-17-mediated immunity to the opportunistic fungal pathogen Candida albicans

    Science.gov (United States)

    Conti, Heather R.; Gaffen, Sarah L.

    2015-01-01

    IL-17 (IL-17A) has emerged as a key mediator of protection against extracellular microbes, but this cytokine also drives pathology in various autoimmune diseases. Overwhelming data in both humans and mice reveal a clear and surprisingly specific role for IL-17 in protection against the fungus Candida albicans, a commensal of the human oral cavity, gastrointestinal tract and reproductive mucosa. The IL-17 pathway regulates antifungal immunity through upregulation of pro-inflammatory cytokines including IL-6, neutrophil-recruiting chemokines such as CXCL1 and CXCL5 and antimicrobial peptides such as the defensins, which act in concert to limit fungal overgrowth. This review will focus on diseases caused by C. albicans, the role of IL-17-mediated immunity in candidiasis, and the implications for clinical therapies for both autoimmune conditions and fungal infections. PMID:26188072

  12. Recent advances on Candida albicans biology and virulence [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Adnane Sellam

    2016-10-01

    Full Text Available Candida albicans is an important human fungal pathogen, in terms of both its clinical significance and its use as an experimental model for scientific investigation. Although this opportunistic pathogen is a natural component of the human flora, it can cause life-threatening infections in immunosuppressed patients. There are currently a limited number of antifungal molecules and drug targets, and increasing resistance to the front-line therapeutics, demonstrating a clear need for new antifungal drugs. Understanding the biology of this pathogen is an important prerequisite for identifying new drug targets for antifungal therapeutics. In this review, we highlight some recent developments that help us to understand how virulence traits are regulated at the molecular level, in addition to technical advances that improve the ability of genome editing in C. albicans.

  13. An interspecies regulatory network inferred from simultaneous RNA-seq of Candida albicans invading innate immune cells

    Directory of Open Access Journals (Sweden)

    Lanay eTierney

    2012-03-01

    Full Text Available The ability to adapt to diverse micro-environmental challenges encountered within a host is of pivotal importance to the opportunistic fungal pathogen C. albicans. We have quantified C.albicans and M. musculus gene expression dynamics during phagocytosis by dendritic cells in a genome-wide, time-resolved analysis using simultaneous RNA-seq. A robust network inference map was generated from this dataset using NetGenerator, predicting novel interactions between the host and the pathogen. We experimentally verified predicted interdependent sub-networkscomprising Hap3 in C. albicans, and Ptx3 and Mta2 in M. musculus. Remarkably, binding of recombinant Ptx3 to the C. albicans cell wall was found to regulate the expression of fungal Hap3 target genes as predicted by the network inference model. Pre-incubation of C. albicans with recombinant Ptx3 significantly altered the expression of Mta2 target cytokines such as IL-2 and IL-4 in a Hap3-dependent manner, further suggesting a role for Mta2 in host-pathogen interplay as predicted in the network inference model. We propose an integrated model for the functionality of these sub-networks during fungal invasion of immune cells, according to which binding of Ptx3 to the C. albicans cell wall induces remodelling via fungal Hap3 target genes, thereby altering the immune response to the pathogen. We show the applicability of network inference to predict interactions between host-pathogen pairs, demonstrating the usefulness of this systems biology approach to decipher mechanisms of microbial pathogenesis.

  14. Candida albicans induces Metabolic Reprogramming in human NK cells and responds to Perforin with a Zinc Depletion Response

    Directory of Open Access Journals (Sweden)

    Daniela eHellwig

    2016-05-01

    Full Text Available As part of the innate immune system, natural killer (NK cells are directly involved in the response to fungal infections. Perforin has been identified as the major effector molecule acting against many fungal pathogens. While several studies have shown that perforin mediated fungicidal effects can contribute to fungal clearance, neither the activation of NK cells by fungal pathogens nor the effects of perforin on fungal cells are well understood. In a dual approach, we have studied the global gene expression pattern of primary and cytokine activated NK cells after co-incubation with C. albicans and the transcriptomic adaptation of C. albicans to perforin exposure. NK cells responded to the fungal pathogen with an up-regulation of genes involved in immune signaling and release of cytokines. Furthermore, we observed a pronounced increase of genes involved in glycolysis and glycolysis inhibitor 2-deoxy-D-glucose impaired C. albicans induced NK cell activation. This strongly indicates that metabolic adaptation is a major part of the NK cell response to C. albicans infections. In the fungal pathogen, perforin induced a strong up-regulation of several fungal genes involved in the zinc depletion response, such as PRA1 and ZRT1. These data suggest that fungal zinc homeostasis is linked to the reaction to perforin secreted by NK cells. However, deletion mutants in PRA1 and ZRT1 did not show altered susceptibility to perforin.

  15. Expression of transglutaminase substrate activity on Candida albicans germ tubes through a coiled, disulfide-bonded N-terminal domain of Hwp1 requires C-terminal glycosylphosphatidylinositol modification.

    Science.gov (United States)

    Staab, Janet F; Bahn, Yong-Sun; Tai, Chia-Hui; Cook, Paul F; Sundstrom, Paula

    2004-09-24

    By serving as a microbial substrate for epithelial cell transglutaminase, Hwp1 (Hyphal wall protein 1) of Candida albicans participates in cross-links with proteins on the mammalian mucosa. Biophysical properties of the transglutaminase substrate domain were explored using a recombinant protein representative of the N-terminal domain of Hwp1 and were similar to other transglutaminase substrates, the small proline-rich proteins of cornified envelopes found in stratified squamous epithelia. Recombinant Hwp1 lacks alpha and beta structures by circular dichroism and likely exists as a disulfide-cross-linked coiled-coil. The transglutaminase substrate property prompted a unique approach for investigating the features of surface Hwp1 on germ tubes. A lysine analog, 5-(biotinamido)pentylamine, was cross-linked to germ tubes catalyzed by transglutaminase 2 prior to cell fractionation, immunoprecipitation, and detection with streptavidin conjugates. The majority of the transglutaminase-modifiable Hwp1 was covalently attached to the beta-glucan of hyphae by the C terminus of Hwp1 via a glycosylphosphatidylinositol remnant anchor. A putative precursor of cell wall forms of Hwp1 was identified in the cell extract and in the culture medium. Hwp1 was modified by relatively short N-linked glycans, and the molecular size of the protein was reduced by hypomannosylation when expressed in O-glycosylation mutant strains. Hwp1 combines features of mammalian transglutaminase substrate proteins with characteristics of fungal cell wall proteins to form an unconventional adhesin at the hyphal wall of C. albicans. Copyright 2004 American Society for Biochemistry and Molecular Biology, Inc.

  16. Separate effects of moisture content and water activity on the hyphal extension of Penicillium rubens on porous media.

    Science.gov (United States)

    van Laarhoven, Karel A; Huinink, Hendrik P; Segers, Frank J J; Dijksterhuis, Jan; Adan, Olaf C G

    2015-12-01

    To prevent indoor fungal growth, understanding the moisture relations of fungi is a key element. Indoor moisture is quantified by the relative humidity (RH). RH controls the water activity of the indoor materials that fungi grow on, a well-studied parameter known to limit fungal growth. RH, however, also controls the amount of water present in these materials, the moisture content. The significance of the moisture content of these materials to indoor fungal growth is currently overlooked. In the work reported here, growth experiments with the indoor fungus Penicillium rubens on gypsum substrates were performed to test whether the moisture content influences growth on porous materials. Second, we report the development of a video microscopy method that for the first time quantified hyphal growth on a porous material. It is found that a higher moisture content leads to earlier colonization and higher hyphal extension rates. This is a fundamental step in unravelling the effect of RH on indoor fungal growth. The real-time monitoring of colonization of gypsum provides a new view of growth on indoor surfaces. © 2015 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Azole Antifungal Resistance in Candida albicans and Emerging Non-albicans Candida Species

    Science.gov (United States)

    Whaley, Sarah G.; Berkow, Elizabeth L.; Rybak, Jeffrey M.; Nishimoto, Andrew T.; Barker, Katherine S.; Rogers, P. David

    2017-01-01

    Within the limited antifungal armamentarium, the azole antifungals are the most frequent class used to treat Candida infections. Azole antifungals such as fluconazole are often preferred treatment for many Candida infections as they are inexpensive, exhibit limited toxicity, and are available for oral administration. There is, however, extensive documentation of intrinsic and developed resistance to azole antifungals among several Candida species. As the frequency of azole resistant Candida isolates in the clinical setting increases, it is essential to elucidate the mechanisms of such resistance in order to both preserve and improve upon the azole class of antifungals for the treatment of Candida infections. This review examines azole resistance in infections caused by C. albicans as well as the emerging non-albicans Candida species C. parapsilosis, C. tropicalis, C. krusei, and C. glabrata and in particular, describes the current understanding of molecular basis of azole resistance in these fungal species. PMID:28127295

  18. Prevalence of yeast other than Candida albicans in denture wearers.

    Science.gov (United States)

    Cavaleiro, Inês; Proença, Luis; Félix, Sérgio; Salema-Oom, Madalena

    2013-07-01

    The isolation of yeast species other than Candida albicans from the oral mucosa has been increasing in frequency, suggesting that those may constitute emerging potential oral colonizers. The purpose of this work was to determine whether yeast species other than C. albicans are associated with factors related to wearing of dental prostheses. tRNA-PCR fingerprinting and sequencing of the 26S rDNA D1/D2 domain were used to identify all yeasts isolated from CHROMagar™ Candida cultures of oral swabs collected from 178 patients. Besides C. albicans, 13 other species were identified, corresponding to 34% of the yeast isolates. The majority of the non-C. albicans species were not detected as single colonizers but rather in co-colonization with one or two other yeasts, often with C. albicans. No significant associations were found with non-C. albicans species. On the contrary, the best-fitted logistic regression model predicts that either wearing a denture (adjusted odds = 4.6) or insufficient oral hygiene (adjusted odds = 2.3) are risks for colonization by yeast, in general. The colonization with non-C. albicans species and co-colonization were not independently associated with any of the analyzed host-related factors. In particular, neither wearing a removable denture nor being elderly were significant predictors. © 2012 by the American College of Prosthodontists.

  19. AI-2 of Aggregatibacter actinomycetemcomitans Inhibits Candida albicans Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Endang W. Bachtiar

    2014-07-01

    Full Text Available Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, and Candida albicans, a polymorphic fungus, are both commensals of the oral cavity but both are opportunistic pathogens that can cause oral diseases. A. actinomycetemcomitans produces a quorum-sensing molecule called autoinducer-2 (AI-2, synthesized by LuxS, that plays an important role in expression of virulence factors, in intra- but also in interspecies communication. The aim of this study was to investigate the role of AI-2 based signaling in the interactions between C. albicans and A. actinomycetemcomitans. A. actinomycetemcomitans adhered to C. albicans and inhibited biofilm formation by means of a molecule that was secreted during growth. C. albicans biofilm formation increased significantly when co-cultured with A. actinomycetemcomitans luxS, lacking AI-2 production. Addition of wild-type-derived spent medium or synthetic AI-2 to spent medium of the luxS strain, restored inhibition of C. albicans biofilm formation to wild-type levels. Addition of synthetic AI-2 significantly inhibited hypha formation of C. albicans possibly explaining the inhibition of biofilm formation. AI-2 of A. actinomycetemcomitans is synthesized by LuxS, accumulates during growth and inhibits C. albicans hypha- and biofilm formation. Identifying the molecular mechanisms underlying the interaction between bacteria and fungi may provide important insight into the balance within complex oral microbial communities.

  20. A fast and simple method to estimate relative, hyphal tensile-strength of filamentous fungi used to assess the effect of autophagy

    DEFF Research Database (Denmark)

    Quintanilla, Daniela; Chelius, Cynthia; Iambamrung, Sirasa

    2018-01-01

    Fungal hyphal strength is an important phenotype which can have a profound impact on bioprocess behavior. Until now, there is not an efficient method which allows its characterization. Currently available methods are very time consuming; thus, compromising their applicability in strain selection...... distribution (PSD) is determined, with analysis time on the order of minutes. Plots of PSD 90th percentile versus time allow estimation of the specific fragmentation rate. This novel method is demonstrated by estimating relative hyphal strength during growth in control conditions and rapamycin...

  1. CO(2 acts as a signalling molecule in populations of the fungal pathogen Candida albicans.

    Directory of Open Access Journals (Sweden)

    Rebecca A Hall

    2010-11-01

    Full Text Available When colonising host-niches or non-animated medical devices, individual cells of the fungal pathogen Candida albicans expand into significant biomasses. Here we show that within such biomasses, fungal metabolically generated CO(2 acts as a communication molecule promoting the switch from yeast to filamentous growth essential for C. albicans pathology. We find that CO(2-mediated intra-colony signalling involves the adenylyl cyclase protein (Cyr1p, a multi-sensor recently found to coordinate fungal responses to serum and bacterial peptidoglycan. We further identify Lys 1373 as essential for CO(2/bicarbonate regulation of Cyr1p. Disruption of the CO(2/bicarbonate receptor-site interferes selectively with C. albicans filamentation within fungal biomasses. Comparisons between the Drosophila melanogaster infection model and the mouse model of disseminated candidiasis, suggest that metabolic CO(2 sensing may be important for initial colonisation and epithelial invasion. Our results reveal the existence of a gaseous Candida signalling pathway and its molecular mechanism and provide insights into an evolutionary conserved CO(2-signalling system.

  2. Synergistic Interactions of Eugenol-tosylate and Its Congeners with Fluconazole against Candida albicans.

    Science.gov (United States)

    Ahmad, Aijaz; Wani, Mohmmad Younus; Khan, Amber; Manzoor, Nikhat; Molepo, Julitha

    2015-01-01

    We previously reported the antifungal properties of a monoterpene phenol "Eugenol" against different Candida strains and have observed that the addition of methyl group to eugenol drastically increased its antimicrobial potency. Based on the results and the importance of medicinal synthetic chemistry, we synthesized eugenol-tosylate and its congeners (E1-E6) and tested their antifungal activity against different clinical fluconazole (FLC)- susceptible and FLC- resistant C. albicans isolates alone and in combination with FLC by determining fractional inhibitory concentration indices (FICIs) and isobolograms calculated from microdilution assays. Minimum inhibitory concentration (MIC) results confirmed that all the tested C. albicans strains were variably susceptible to the semi-synthetic derivatives E1-E6, with MIC values ranging from 1-62 μg/ml. The test compounds in combination with FLC exhibited either synergy (36%), additive (41%) or indifferent (23%) interactions, however, no antagonistic interactions were observed. The MICs of FLC decreased 2-9 fold when used in combination with the test compounds. Like their precursor eugenol, all the derivatives showed significant impairment of ergosterol biosynthesis in all C. albicans strains coupled with down regulation of the important ergosterol biosynthesis pathway gene-ERG11. The results were further validated by docking studies, which revealed that the inhibitors snugly fitting the active site of the target enzyme, mimicking fluconazole, may well explain their excellent inhibitory activity. Our results suggest that these compounds have a great potential as antifungals, which can be used as chemosensitizing agents with the known antifungal drugs.

  3. An Optimized Lock Solution Containing Micafungin, Ethanol and Doxycycline Inhibits Candida albicans and Mixed C. albicans – Staphyloccoccus aureus Biofilms

    Science.gov (United States)

    Lown, Livia; Peters, Brian M.; Walraven, Carla J.; Noverr, Mairi C.; Lee, Samuel A.

    2016-01-01

    Candida albicans is a major cause of catheter-related bloodstream infections and is associated with high morbidity and mortality. Due to the propensity of C. albicans to form drug-resistant biofilms, the current standard of care includes catheter removal; however, reinsertion may be technically challenging or risky. Prolonged exposure of an antifungal lock solution within the catheter in conjunction with systemic therapy has been experimentally attempted for catheter salvage. Previously, we demonstrated excellent in vitro activity of micafungin, ethanol, and high-dose doxycycline as single agents for prevention and treatment of C. albicans biofilms. Thus, we sought to investigate optimal combinations of micafungin, ethanol, and/or doxycycline as a lock solution. We performed two- and three-drug checkerboard assays to determine the in vitro activity of pairwise or three agents in combination for prevention or treatment of C. albicans biofilms. Optimal lock solutions were tested for activity against C. albicans clinical isolates, reference strains and polymicrobial C. albicans-S. aureus biofilms. A solution containing 20% (v/v) ethanol, 0.01565 μg/mL micafungin, and 800 μg/mL doxycycline demonstrated a reduction of 98% metabolic activity and no fungal regrowth when used to prevent fungal biofilm formation; however there was no advantage over 20% ethanol alone. This solution was also successful in inhibiting the regrowth of C. albicans from mature polymicrobial biofilms, although it was not fully bactericidal. Solutions containing 5% ethanol with low concentrations of micafungin and doxycycline demonstrated synergistic activity when used to prevent monomicrobial C. albicans biofilm formation. A combined solution of micafungin, ethanol and doxycycline is highly effective for the prevention of C. albicans biofilm formation but did not demonstrate an advantage over 20% ethanol alone in these studies. PMID:27428310

  4. Integrating Candida albicans metabolism with biofilm heterogeneity by transcriptome mapping

    Science.gov (United States)

    Rajendran, Ranjith; May, Ali; Sherry, Leighann; Kean, Ryan; Williams, Craig; Jones, Brian L.; Burgess, Karl V.; Heringa, Jaap; Abeln, Sanne; Brandt, Bernd W.; Munro, Carol A.; Ramage, Gordon

    2016-10-01

    Candida albicans biofilm formation is an important virulence factor in the pathogenesis of disease, a characteristic which has been shown to be heterogeneous in clinical isolates. Using an unbiased computational approach we investigated the central metabolic pathways driving biofilm heterogeneity. Transcripts from high (HBF) and low (LBF) biofilm forming isolates were analysed by RNA sequencing, with 6312 genes identified to be expressed in these two phenotypes. With a dedicated computational approach we identified and validated a significantly differentially expressed subnetwork of genes associated with these biofilm phenotypes. Our analysis revealed amino acid metabolism, such as arginine, proline, aspartate and glutamate metabolism, were predominantly upregulated in the HBF phenotype. On the contrary, purine, starch and sucrose metabolism was generally upregulated in the LBF phenotype. The aspartate aminotransferase gene AAT1 was found to be a common member of these amino acid pathways and significantly upregulated in the HBF phenotype. Pharmacological inhibition of AAT1 enzyme activity significantly reduced biofilm formation in a dose-dependent manner. Collectively, these findings provide evidence that biofilm phenotype is associated with differential regulation of metabolic pathways. Understanding and targeting such pathways, such as amino acid metabolism, is potentially useful for developing diagnostics and new antifungals to treat biofilm-based infections.

  5. Candida albicans and napkin dermatitis: relationship and lesion ...

    African Journals Online (AJOL)

    Candida albicans and napkin dermatitis: relationship and lesion severity correlation. Amani Hussein Ahmed Karsani, Abdullateef Azolaibani, Yasser Farouq, Khalid Zedan, Mohammed Mohsen Alotaibi, Ghada Bin Saif, Ibrahim H. Babikir ...

  6. Molecular genetic techniques for gene manipulation in Candida albicans

    Science.gov (United States)

    Xu, Qiu-Rong; Yan, Lan; Lv, Quan-Zhen; Zhou, Mi; Sui, Xue; Cao, Yong-Bing; Jiang, Yuan-Ying

    2014-01-01

    Candida albicans is one of the most common fungal pathogen in humans due to its high frequency as an opportunistic and pathogenic fungus causing superficial as well as invasive infections in immunocompromised patients. An understanding of gene function in C. albicans is necessary to study the molecular basis of its pathogenesis, virulence and drug resistance. Several manipulation techniques have been used for investigation of gene function in C. albicans, including gene disruption, controlled gene expression, protein tagging, gene reintegration, and overexpression. In this review, the main cassettes containing selectable markers used for gene manipulation in C. albicans are summarized; the advantages and limitations of these cassettes are discussed concerning the influences on the target gene expression and the virulence of the mutant strains. PMID:24759671

  7. Innate immune cell response upon Candida albicans infection

    Science.gov (United States)

    Qin, Yulin; Zhang, Lulu; Xu, Zheng; Zhang, Jinyu; Jiang, Yuan-ying; Cao, Yongbing; Yan, Tianhua

    2016-01-01

    abstract Candida albicans is a polymorphic fungus which is the predominant cause of superficial and deep tissue fungal infections. This microorganism has developed efficient strategies to invade the host and evade host defense systems. However, the host immune system will be prepared for defense against the microbe by recognition of receptors, activation of signal transduction pathways and cooperation of immune cells. As a consequence, C. albicans could either be eliminated by immune cells rapidly or disseminate hematogenously, leading to life-threatening systemic infections. The interplay between Candida albicans and the host is complex, requiring recognition of the invaded pathogens, activation of intricate pathways and collaboration of various immune cells. In this review, we will focus on the effects of innate immunity that emphasize the first line protection of host defense against invaded C. albicans including the basis of receptor-mediated recognition and the mechanisms of cell-mediated immunity. PMID:27078171

  8. Global Identification of Biofilm-Specific Proteolysis in Candida albicans.

    Science.gov (United States)

    Winter, Michael B; Salcedo, Eugenia C; Lohse, Matthew B; Hartooni, Nairi; Gulati, Megha; Sanchez, Hiram; Takagi, Julie; Hube, Bernhard; Andes, David R; Johnson, Alexander D; Craik, Charles S; Nobile, Clarissa J

    2016-09-13

    Candida albicans is a fungal species that is part of the normal human microbiota and also an opportunistic pathogen capable of causing mucosal and systemic infections. C. albicans cells proliferate in a planktonic (suspension) state, but they also form biofilms, organized and tightly packed communities of cells attached to a solid surface. Biofilms colonize many niches of the human body and persist on implanted medical devices, where they are a major source of new C. albicans infections. Here, we used an unbiased and global substrate-profiling approach to discover proteolytic activities produced specifically by C. albicans biofilms, compared to planktonic cells, with the goal of identifying potential biofilm-specific diagnostic markers and targets for therapeutic intervention. This activity-based profiling approach, coupled with proteomics, identified Sap5 (Candidapepsin-5) and Sap6 (Candidapepsin-6) as major biofilm-specific proteases secreted by C. albicans Fluorogenic peptide substrates with selectivity for Sap5 or Sap6 confirmed that their activities are highly upregulated in C. albicans biofilms; we also show that these activities are upregulated in other Candida clade pathogens. Deletion of the SAP5 and SAP6 genes in C. albicans compromised biofilm development in vitro in standard biofilm assays and in vivo in a rat central venous catheter biofilm model. This work establishes secreted proteolysis as a promising enzymatic marker and potential therapeutic target for Candida biofilm formation. Biofilm formation by the opportunistic fungal pathogen C. albicans is a major cause of life-threatening infections. This work provides a global characterization of secreted proteolytic activity produced specifically by C. albicans biofilms. We identify activity from the proteases Sap5 and Sap6 as highly upregulated during C. albicans biofilm formation and develop Sap-cleavable fluorogenic substrates that enable the detection of biofilms from C. albicans and also

  9. Factors Supporting Cysteine Tolerance and Sulfite Production in Candida albicans

    OpenAIRE

    Hennicke, Florian; Grumbt, Maria; Lermann, Ulrich; Ueberschaar, Nico; Palige, Katja; Böttcher, Bettina; Jacobsen, Ilse D.; Staib, Claudia; Morschhäuser, Joachim; Monod, Michel; Hube, Bernhard; Hertweck, Christian; Staib, Peter

    2013-01-01

    The amino acid cysteine has long been known to be toxic at elevated levels for bacteria, fungi, and humans. However, mechanisms of cysteine tolerance in microbes remain largely obscure. Here we show that the human pathogenic yeast Candida albicans excretes sulfite when confronted with increasing cysteine concentrations. Mutant construction and phenotypic analysis revealed that sulfite formation from cysteine in C. albicans relies on cysteine dioxygenase Cdg1, an enzyme with similar functions ...

  10. Standardization of hyphal growth inhibition rate as a means of evaluating Microsporum spp. in vitro susceptibility to terbinafine, griseofulvin, and ciclopiroxolamine.

    Science.gov (United States)

    Biancalana, Fernanda Simas Corrêa; Lyra, Luzia; Moretti, Maria Luiza; Kamei, Katsuhiko; Schreiber, Angélica Zaninelli

    2011-10-01

    Reference methods for antifungal susceptibility tests recommend the use of conidia as inoculum. However, some isolates produce few conidia, while the invasive form of filamentous fungi in general is hyphae making susceptibility tests infeaseble. These facts suggest that other than conidia broth dilution method is required for susceptibility tests. The aim of this study was to clarify if the hyphal growth inhibition rate could be used as a method of determining the antifungal susceptibility of genus Microsporum. For this reason, a method which traces hyphal tips automatically and measures their growth rate was standardized for Microsporum spp. Control growth curves and test growth curves obtained by real-time observation of the hyphae groups responses to different concentrations of terbinafine, griseofulvin, and ciclopiroxolamine were used to compare with minimum inhibitory concentrations (MICs) obtained by conidia broth microdilution method. A visible reduction in the growth inhibition rate was observed when hyphal activity was evaluated using the third or fourth serial two-fold dilution below the MIC determined by broth microdilution for terbinafine and ciclopiroxolamine. For griseofulvin, this reduction occurred after the fifth dilution below the MIC. This study highlights the importance of the inoculum type used to determine the in vitro susceptibility of Microsporum strains. We conclude that measurement of hyphal growth inhibition, despite being time consuming, could be a suitable method for evaluating antifungal susceptibility, particularly for fungi as Microsporum spp. that produce a small (or not at all) number of conidia.

  11. Effectiveness of magnetic fluid hyperthermia against Candida albicans cells.

    Science.gov (United States)

    Chudzik, Barbara; Miaskowski, Arkadiusz; Surowiec, Zbigniew; Czernel, Grzegorz; Duluk, Tomasz; Marczuk, Andrzej; Gagoś, Mariusz

    2016-12-01

    Candida albicans is one of the most frequently isolated fungal pathogens causing opportunistic infections in humans. Targeted magnetic fluid hyperthermia (MFH) is a promising method in thermal therapy facilitating selective heating of pathogen cells like C. albicans. In the paper, we used meso-2,3-dimercaptosuccinic acid (DMSA)-coated magnetic nanoparticles (MNPs) and functionalised anti-C. albicans immunomagnetic nanoparticles (IMNPs) to investigate the potential of MFH in combating C. albicans cells in vitro. Using Mössbauer spectroscopy it was found that synthesised MNPs exhibited superparamagnetic phenomena. On the basis of calorimetric experiments, the maximum SAR (specific absorption rate) was found and a proper concentration of MNPs was established to control the temperature. MFH based on both DMSA-coated MNPs and functionalised anti-C. albicans IMNPs was more effective in combating C. albicans cells in vitro than thermostat hyperthermia. Especially promising results were obtained using functionalised IMNPs, which eradicated most of the pathogen colonies at the temperature of 43 °C.

  12. Candida albicans survival and biofilm formation under starvation conditions.

    Science.gov (United States)

    Ning, Y; Hu, X; Ling, J; Du, Y; Liu, J; Liu, H; Peng, Z

    2013-01-01

    To investigate the survival and biofilm formation capacity of Candida albicans in starvation and under anaerobic conditions. Candida albicans growth and survival were monitored in vitro for up to 8 months. Fungal suspensions from late exponential, stationary and starvation phases were incubated on human dentine, polystyrene and glass slides. Scanning electron microscopy (SEM) was used to observe the process of biofilm formation. 2,3-bis(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide inner salt (XTT) reduction assay was performed to quantify the biofilm formation capability, and confocal laser scanning microscopy (CLSM) was used to study and make semi-quantitative comparisons of the ultrastructure of biofilms formed on human dentine. 'XTT bioactivity' and 'COMSTAT results' were analysed by two-way analysis of variance (ANOVA) and one-way ANOVA, respectively. Candida albicans survived for over six months. SEM demonstrated that starving C. albicans produced mature biofilms on different substrata. C. albicans of the same growth phase incubated on human dentine displayed significantly higher biofilm formation capability than on polystyrene or glass slides (P roughness coefficient and surface/volume ratio (P < 0.05). Candida albicans cells can survive and form biofilms in anaerobic and nutrient-limited conditions and may pose a treatment challenge. © 2012 International Endodontic Journal.

  13. Silencing of DND1 in potato and tomato impedes conidial germination, attachment and hyphal growth of Botrytis cinerea.

    Science.gov (United States)

    Sun, Kaile; van Tuinen, Ageeth; van Kan, Jan A L; Wolters, Anne-Marie A; Jacobsen, Evert; Visser, Richard G F; Bai, Yuling

    2017-12-06

    Botrytis cinerea, a necrotrophic pathogenic fungus, attacks many crops including potato and tomato. Major genes for complete resistance to B. cinerea are not known in plants, but a few quantitative trait loci have been described in tomato. Loss of function of particular susceptibility (S) genes appears to provide a new source of resistance to B. cinerea in Arabidopsis. In this study, orthologs of Arabidopsis S genes (DND1, DMR6, DMR1 and PMR4) were silenced by RNAi in potato and tomato (only for DND1). DND1 well-silenced potato and tomato plants showed significantly reduced diameters of B. cinerea lesions as compared to control plants, at all-time points analysed. Reduced lesion diameter was also observed on leaves of DMR6 silenced potato plants but only at 3 days post inoculation (dpi). The DMR1 and PMR4 silenced potato transformants were as susceptible as the control cv Desiree. Microscopic analysis was performed to observe B. cinerea infection progress in DND1 well-silenced potato and tomato leaves. A significantly lower number of B. cinerea conidia remained attached to the leaf surface of DND1 well-silenced potato and tomato plants and the hyphal growth of germlings was hampered. This is the first report of a cytological investigation of Botrytis development on DND1-silenced crop plants. Silencing of DND1 led to reduced susceptibility to Botrytis, which was associated with impediment of conidial germination and attachment as well as hyphal growth. Our results provide new insights regarding the use of S genes in resistance breeding.

  14. Epidemiology of Candida albicans and non-C.albicans of neonatal candidemia at a tertiary care hospital in western China.

    Science.gov (United States)

    Fu, Jinjian; Ding, Yanling; Wei, Ba; Wang, Lin; Xu, Shaolin; Qin, Peixu; Wei, Liuhua; Jiang, Lijun

    2017-05-06

    Although the majority of Candida infections occur in the developing world, candidemia epidemiology is poorly understood in these countries. The aim of this study was to investigate the epidemiology of non-Candida albicans (non-C. albicans) candidemia among neonates at Liuzhou Maternity and Child Healthcare Hospital in China. A retrospective review of all positive blood culture about Candida species in neonatal intensive care unit was conducted between January 2012 and November 2015. Information about demographics, risk factors and outcome of candidemia were collected. Univariate and multivariate logistic regression models were used to identify the risk factors associated with the development of non-C.albicans candidemia. The prevalence of candidemia in infants was 1.4%. Non-C.albicans was responsible for 56.5% of neonatal candidemia. The predisposing factors for development of non-C.albicans candidemia among infants included mechanical ventilation [odds ratio (OR), 95% confidence interval (95%CI) = 3.13, 1.07-9.14; P = 0.037] and use of assisted reproductive technology (OR, 95%CI = 4.52, 1.39-14.77; P = 0.012). The overall mortality rate of candidemia was 8.7% and non-C.albicans attributed to 83.3% of all mortalities. Non-C.albicans species are the major cause of candidemia in local neonatal group. The study highlights the urgent needs to evaluate the possibility of development of non-C.albicans candidemia in neonates exposed to these risk factors and much emphasis must be laid on the early implementation of medical intervention to reduce the incidences of candidemia in neonates.

  15. Unique Function of the Bacterial Chromosome Segregation Machinery in Apically Growing Streptomyces - Targeting the Chromosome to New Hyphal Tubes and its Anchorage at the Tips.

    Directory of Open Access Journals (Sweden)

    Agnieszka Kois-Ostrowska

    2016-12-01

    Full Text Available The coordination of chromosome segregation with cell growth is fundamental to the proliferation of any organism. In most unicellular bacteria, chromosome segregation is strictly coordinated with cell division and involves ParA that moves the ParB nucleoprotein complexes bi- or unidirectionally toward the cell pole(s. However, the chromosome organization in multiploid, apically extending and branching Streptomyces hyphae challenges the known mechanisms of bacterial chromosome segregation. The complex Streptomyces life cycle involves two stages: vegetative growth and sporulation. In the latter stage, multiple cell divisions accompanied by chromosome compaction and ParAB assisted segregation turn multigenomic hyphal cell into a chain of unigenomic spores. However, the requirement for active chromosome segregation is unclear in the absence of canonical cell division during vegetative growth except in the process of branch formation. The mechanism by which chromosomes are targeted to new hyphae in streptomycete vegetative growth has remained unknown until now. Here, we address the question of whether active chromosome segregation occurs at this stage. Applied for the first time in Streptomyces, labelling of the chromosomal replication initiation region (oriC and time-lapse microscopy, revealed that in vegetative hyphae every copy of the chromosome is complexed with ParB, whereas ParA, through interaction with the apical protein complex (polarisome, tightly anchors only one chromosome at the hyphal tip. The anchor is maintained during replication, when ParA captures one of the daughter oriCs. During spore germination and branching, ParA targets one of the multiple chromosomal copies to the new hyphal tip, enabling efficient elongation of hyphal tube. Thus, our studies reveal a novel role for ParAB proteins during hyphal tip establishment and extension.

  16. Unique Function of the Bacterial Chromosome Segregation Machinery in Apically Growing Streptomyces - Targeting the Chromosome to New Hyphal Tubes and its Anchorage at the Tips.

    Science.gov (United States)

    Kois-Ostrowska, Agnieszka; Strzałka, Agnieszka; Lipietta, Natalia; Tilley, Emma; Zakrzewska-Czerwińska, Jolanta; Herron, Paul; Jakimowicz, Dagmara

    2016-12-01

    The coordination of chromosome segregation with cell growth is fundamental to the proliferation of any organism. In most unicellular bacteria, chromosome segregation is strictly coordinated with cell division and involves ParA that moves the ParB nucleoprotein complexes bi- or unidirectionally toward the cell pole(s). However, the chromosome organization in multiploid, apically extending and branching Streptomyces hyphae challenges the known mechanisms of bacterial chromosome segregation. The complex Streptomyces life cycle involves two stages: vegetative growth and sporulation. In the latter stage, multiple cell divisions accompanied by chromosome compaction and ParAB assisted segregation turn multigenomic hyphal cell into a chain of unigenomic spores. However, the requirement for active chromosome segregation is unclear in the absence of canonical cell division during vegetative growth except in the process of branch formation. The mechanism by which chromosomes are targeted to new hyphae in streptomycete vegetative growth has remained unknown until now. Here, we address the question of whether active chromosome segregation occurs at this stage. Applied for the first time in Streptomyces, labelling of the chromosomal replication initiation region (oriC) and time-lapse microscopy, revealed that in vegetative hyphae every copy of the chromosome is complexed with ParB, whereas ParA, through interaction with the apical protein complex (polarisome), tightly anchors only one chromosome at the hyphal tip. The anchor is maintained during replication, when ParA captures one of the daughter oriCs. During spore germination and branching, ParA targets one of the multiple chromosomal copies to the new hyphal tip, enabling efficient elongation of hyphal tube. Thus, our studies reveal a novel role for ParAB proteins during hyphal tip establishment and extension.

  17. Differential effects of antifungal agents on expression of genes related to formation of Candida albicans biofilms.

    Science.gov (United States)

    Chatzimoschou, Athanasios; Simitsopoulou, Maria; Antachopoulos, Charalampos; Walsh, Thomas J; Roilides, Emmanuel

    2016-01-01

    The purpose of this study was to analyse specific molecular mechanisms involved in the intrinsic resistance of C. albicans biofilms to antifungals. We investigated the transcriptional profile of three genes (BGL2, SUN41, ECE1) involved in Candida cell wall formation in response to voriconazole or anidulafungin after the production of intermediate and mature biofilms. C. albicans M61, a well-documented biofilm producer strain, was used for the development of intermediate (12 h and 18 h) and completely mature biofilms (48 h). After exposure of cells from each biofilm growth mode to voriconazole (128 and 512 mg l(-1)) or anidulafungin (0.25 and 1 mg l(-1)) for 12-24 h, total RNA samples extracted from biofilm cells were analysed by RT-PCR. The voriconazole and anidulafungin biofilm MIC was 512 and 0.5 mg l(-1) respectively. Anidulafungin caused significant up-regulation of SUN41 (3.7-9.3-fold) and BGL2 (2.2-2.8 fold) in intermediately mature biofilms; whereas, voriconazole increased gene expression in completely mature biofilms (SUN41 2.3-fold, BGL2 2.1-fold). Gene expression was primarily down-regulated by voriconazole in intermediately, but not completely mature biofilms. Both antifungals caused down-regulation of ECE1 in intermediately mature biofilms. © 2015 Blackwell Verlag GmbH.

  18. Candida albicans keratitis in an immunocompromised patient

    Directory of Open Access Journals (Sweden)

    H Mohammed J Hassan

    2010-10-01

    Full Text Available H Mohammed J Hassan1, Theocharis Papanikolaou2, Georgios Mariatos1, Amany Hammad3, Hala Hassan41Ophthalmology Department, Barnsley Hospital NHS Foundation Trust, South Yorkshire, England, UK; 2Ophthalmology Department, Cambridge University Hospitals NHS Foundation Trust, England, UK; 3Ophthalmology Department, Rotherham Hospital NHS Foundation Trust, England, UK; 4Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, England, UKPurpose: When investigating a case of unexplained corneal ulceration, we need to think of fungal infection and any predisposing factors.Methods: A case study of a corneal ulceration in a patient who was HIV positive with a devastating visual outcome.Results: Therapeutic corneal graft was necessary due to corneal perforation. Immunocompromised state of patient was retrospectively diagnosed.Conclusions: Candida albicans keratitis is an opportunistic infection of a compromised cornea, and sometimes unknowingly compromised host, which can be initially misdiagnosed. Despite intensive antifungal therapy, occasionally patients require corneal grafting to improve vision, and before it is possible to establish an accurate diagnosis.Keywords: fungal keratitis, corneal perforation, keratoplasty, human immunodeficiency virus, HIV

  19. Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo.

    Science.gov (United States)

    Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Li, Yong; Krysan, Damian J; Koo, Hyun

    2017-06-01

    Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1-2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of GtfB-Candida interactions

  20. Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo

    Science.gov (United States)

    Liu, Yuan; Kim, Dongyeop; Li, Yong; Krysan, Damian J.

    2017-01-01

    Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1–2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of Gtf

  1. Frequency of Candida albicans in Patients with Funguria

    International Nuclear Information System (INIS)

    Jamil, S.; Jamil, N.; Hafiz, S.; Siddiqui, S.; Saad, U.

    2016-01-01

    Objective: To determine the frequency of Candida albicans in patients with funguria. Study Design: Descriptive cross-sectional study. Place and Duration of Study: Department of Microbiology, Sindh Institute of Urology and Transplantation, from July to December 2012. Methodology: Patients urine samples with fungus/Candida were included. Candida albicans was identified by the production of tubular structures (germ tubes) on microscopy as per standard procedure followed by inoculation on Chrom agar (Oxoid) and Corn Meal-Tween 80 agar (Oxoid). The identification of other non-albicans Candida species was also done both microscopically and macroscopically as per standard procedure. Results: Out of the 289 isolates, 204 (70.6 percentage) were male patients and 85 (29.4 percentage) were female patients, with 165 (57.1 percentage) from the out-patients and 124 (42.9 percentage) from the in-patients. Five species of Candida were found to be prevalent including 87 (30.1 percentage) Candida albicans, 176 (60.9 percentage) Candida tropicalis, 14 (4.8 percentage) Candida parapsilosis, 8 (2.8 percentage) Candida glabrata and 4 (1.4 percentage) Candida lusitaniae. Majority of patients with funguria were aged above 50 years (60.2 percentage). Conclusion: In the present study, 30.1 percentage patients with funguria had Candida albicans. The most frequently isolated species was Candida tropicalis (60.9 percentage), followed by other non-albicans Candida. This study has shown the emergence of non-albicans Candida as a major cause of candiduria. (author)

  2. Cellular Components Mediating Coadherence of Candida albicans and Fusobacterium nucleatum.

    Science.gov (United States)

    Wu, T; Cen, L; Kaplan, C; Zhou, X; Lux, R; Shi, W; He, X

    2015-10-01

    Candida albicans is an opportunistic fungal pathogen found as part of the normal oral flora. It can be coisolated with Fusobacterium nucleatum, an opportunistic bacterial pathogen, from oral disease sites, such as those involved in refractory periodontitis and pulp necrosis. The physical coadherence between these 2 clinically important microbes has been well documented and suggested to play a role in facilitating their oral colonization and colocalization and contributing to polymicrobial pathogenesis. Previous studies indicated that the physical interaction between C. albicans and F. nucleatum was mediated by the carbohydrate components on the surface of C. albicans and the protein components on the Fusobaterium cell surface. However, the identities of the components involved still remain elusive. This study was aimed at identifying the genetic determinants involved in coaggregation between the 2 species. By screening a C. albicans SN152 mutant library and a panel of F. nucleatum 23726 outer membrane protein mutants, we identified FLO9, which encodes a putative adhesin-like cell wall mannoprotein of C. albicans and radD, an arginine-inhibitable adhesin-encoding gene in F. nucleatum that is involved in interspecies coadherence. Consistent with these findings, we demonstrated that the strong coaggregation between wild-type F. nucleatum 23726 and C. albicans SN152 in an in vitro assay could be greatly inhibited by arginine and mannose. Our study also suggested a complex multifaceted mechanism underlying physical interaction between C. albicans and F. nucleatum and for the first time revealed the identity of major genetic components involved in mediating the coaggregation. These observations provide useful knowledge for developing new targeted treatments for disrupting interactions between these 2 clinically relevant pathogens. © International & American Associations for Dental Research 2015.

  3. Dataset on preparation of the phosphorylated counterparts of a Momordica charantia protein for studying antifungal activities against susceptible dose-dependent C. albicans to antimycotics.

    Science.gov (United States)

    Qiao, Yuanbiao; Song, Li; Zhu, Chenchen; Wang, Qian; Guo, Tianyan; Yan, Yanhua; Li, Qingshan

    2017-12-01

    The data presented here are related to a research article entitled "Development of a phosphorylated Momordica charantia protein system for inhibiting susceptible dose-dependent C. albicans to available antimycotics: An allosteric regulation of protein" (Qiao et al., 2017) [1]. The data set includes three portions: (1) a relationship between reaction velocities of protein phosphorylation as a function of the substrate concentrations, determined in enzymatic reactions in aid of protein kinases; (2) a result of antifungal susceptibility testing of C. albicans after it is selected in antimycotics; and (3) a comparison of protein expression in the susceptible dose-dependent fungus relative to the wild C. albicans . In the first portion, the relationship of reaction velocities and substrate concentrations is expressed as an output from the inverse variation model. All data and analyses are made publicly available and citied in the research article using a style for the Data in Brief.

  4. Daya hambat xylitol dan nistation terhadap pertumbuhan Candida albicans (in vitro (Inhibition effect of xylitol and nistatin combination on Candida albicans growth (in vitro

    Directory of Open Access Journals (Sweden)

    Sarah Kartimah Djajusman

    2014-09-01

    Full Text Available Background: The growth of Candida albicans can be controlled by using antifungal such as nystatin. These days we found that using antifungal is not enough to control Candida albicans, we also have to control the intake of sugar by using xylitol. Purpose: Purpose of the study was to determine the optimal inhibitory concentration of xylitol-nystatin in the Candida albicans growth. Methods: This was an in-vitro study using an antimicrobial test of serial dilution with xylitol-nystatin and sucrose–nystatin consentration of 1%, 3%, 5%, 7%, 9%, and 10%.Growth inhibition of C. albicans was determined by the inhibition zone of xylitol + nystatin on C. albicans culture media (in vitro Results: The result of study was the inhibitory consentration of xylitol-nystatin to inhibit Candida albicans growth was 3%-10%. Conclusion: The study showed that combination of xylitol and nystation could inhibit the growth of Candida albicans.Latar belakang: Pertumbuhan Candida albicans dapat dikontrol dengan menggunakan antijamur seperti nistatin. Penggunakan antijamur saja tidak cukup untuk mengontrol Candida albicans, namun perlu pula mengontrol asupan gula dengan menggunakan xylitol. Tujuan: Tujuan dari penelitian ini adalah untuk menentukan konsentrasi hambat optimal xylitol-nistatin dalam pertumbuhan Candida albicans. Metode: Penelitian ini merupakan penelitian in vitro menggunakan uji antimikroba pengenceran serial dengan xylitol-nistatin dan nystatin-sukrosa konsentrasi 1%, 3 %, 5 %, 7%, 9%, dan 10%. Daya hambat pertumbuhan C. albicans diukur dari zona hambat xylitol + nistatin pada media kultur C. albicans (in vitro Hasil: Konsentrasi penghambatan xylitol-nistatin untuk menghambat pertumbuhan Candida albicans adalah 3-10%. Simpulan: Hasil penelitian menunjukkan bahwa kombinasi xylitol dan nystation bisa menghambat pertumbuhan Candida albicans.

  5. Nicotine Enhances Interspecies Relationship between Streptococcus mutans and Candida albicans

    Directory of Open Access Journals (Sweden)

    Shiyu Liu

    2017-01-01

    Full Text Available Streptococcus mutans and Candida albicans are common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies between S. mutans and C. albicans is explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS, and expression of glucosyltransferases (Gtfs. Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. More C. albicans cells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showed gtfs expression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth of S. mutans, and more S. mutans cells attracted more C. albicans cells due to the interaction between two species. Since S. mutans and C. albicans are putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

  6. Candida albicans secreted aspartyl proteinases in virulence and pathogenesis.

    Science.gov (United States)

    Naglik, Julian R; Challacombe, Stephen J; Hube, Bernhard

    2003-09-01

    Candida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known, in vitro, animal, and human studies have implicated the proteinases in C. albicans virulence in one of the following seven ways: (i) correlation between Sap production in vitro and Candida virulence, (ii) degradation of human proteins and structural analysis in determining Sap substrate specificity, (iii) association of Sap production with other virulence processes of C. albicans, (iv) Sap protein production and Sap immune responses in animal and human infections, (v) SAP gene expression during Candida infections, (vi) modulation of C. albicans virulence by aspartyl proteinase inhibitors, and (vii) the use of SAP-disrupted mutants to analyze C. albicans virulence. Sap proteins fulfill a number of specialized functions during the infective process, which include the simple role of digesting molecules for nutrient acquisition, digesting or distorting host cell membranes to facilitate adhesion and tissue invasion, and digesting cells and molecules of the host immune system to avoid or resist antimicrobial attack by the host. We have critically discussed the data relevant to each of these seven criteria, with specific emphasis on how this proteinase family could contribute to Candida virulence and pathogenesis.

  7. Nicotine Enhances Interspecies Relationship between Streptococcus mutans and Candida albicans.

    Science.gov (United States)

    Liu, Shiyu; Qiu, Wei; Zhang, Keke; Zhou, Xuedong; Ren, Biao; He, Jinzhi; Xu, Xin; Cheng, Lei; Li, Mingyun

    2017-01-01

    Streptococcus mutans and Candida albicans are common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies between S. mutans and C. albicans is explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS), and expression of glucosyltransferases (Gtfs). Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. More C. albicans cells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showed gtfs expression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth of S. mutans , and more S. mutans cells attracted more C. albicans cells due to the interaction between two species. Since S. mutans and C. albicans are putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

  8. RNA-Seq Reveals Enhanced Sugar Metabolism in Streptococcus mutans Co-cultured with Candida albicans within Mixed-Species Biofilms

    Science.gov (United States)

    He, Jinzhi; Kim, Dongyeop; Zhou, Xuedong; Ahn, Sang-Joon; Burne, Robert A.; Richards, Vincent P.; Koo, Hyun

    2017-01-01

    Early childhood caries (ECC), which can lead to rampant tooth-decay that is painful and costly to treat, is one of the most prevalent infectious diseases affecting children worldwide. Previous studies support that interactions between Streptococcus mutans and Candida albicans are associated with the pathogenesis of ECC. The presence of Candida enhances S. mutans growth, fitness and accumulation within biofilms in vitro, although the molecular basis for these behaviors is undefined. Using an established co-cultivation biofilm model and RNA-Seq, we investigated how C. albicans influences the transcriptome of S. mutans. The presence of C. albicans dramatically altered gene expression in S. mutans in the dual-species biofilm, resulting in 393 genes differentially expressed, compared to mono-species biofilms of S. mutans. By Gene Ontology analysis, the majority of up-regulated genes were related to carbohydrate transport and metabolic/catabolic processes. KEGG pathway impact analysis showed elevated pyruvate and galactose metabolism, suggesting that co-cultivation with C. albicans influences carbohydrate utilization by S. mutans. Analysis of metabolites confirmed the increases in carbohydrate metabolism, with elevated amounts of formate in the culture medium of co-cultured biofilms. Moreover, co-cultivation with C. albicans altered transcription of S. mutans signal transduction (comC and ciaRH) genes associated with fitness and virulence. Interestingly, the expression of genes for mutacins (bacteriocins) and CRISPR were down-regulated. Collectively, the data provide a comprehensive insight into S. mutans transcriptomic changes induced by C. albicans, and offer novel insights into how bacterial–fungal interactions may enhance the severity of dental caries. PMID:28642749

  9. RNA-Seq Reveals Enhanced Sugar Metabolism in Streptococcus mutans Co-cultured with Candida albicans within Mixed-Species Biofilms

    Directory of Open Access Journals (Sweden)

    Jinzhi He

    2017-06-01

    Full Text Available Early childhood caries (ECC, which can lead to rampant tooth-decay that is painful and costly to treat, is one of the most prevalent infectious diseases affecting children worldwide. Previous studies support that interactions between Streptococcus mutans and Candida albicans are associated with the pathogenesis of ECC. The presence of Candida enhances S. mutans growth, fitness and accumulation within biofilms in vitro, although the molecular basis for these behaviors is undefined. Using an established co-cultivation biofilm model and RNA-Seq, we investigated how C. albicans influences the transcriptome of S. mutans. The presence of C. albicans dramatically altered gene expression in S. mutans in the dual-species biofilm, resulting in 393 genes differentially expressed, compared to mono-species biofilms of S. mutans. By Gene Ontology analysis, the majority of up-regulated genes were related to carbohydrate transport and metabolic/catabolic processes. KEGG pathway impact analysis showed elevated pyruvate and galactose metabolism, suggesting that co-cultivation with C. albicans influences carbohydrate utilization by S. mutans. Analysis of metabolites confirmed the increases in carbohydrate metabolism, with elevated amounts of formate in the culture medium of co-cultured biofilms. Moreover, co-cultivation with C. albicans altered transcription of S. mutans signal transduction (comC and ciaRH genes associated with fitness and virulence. Interestingly, the expression of genes for mutacins (bacteriocins and CRISPR were down-regulated. Collectively, the data provide a comprehensive insight into S. mutans transcriptomic changes induced by C. albicans, and offer novel insights into how bacterial–fungal interactions may enhance the severity of dental caries.

  10. Prediction of antigenic sites on ALS1 and HWP1 protein sequences in vaginal isolated C. albicans of using bioinformatics analysis

    Directory of Open Access Journals (Sweden)

    Mona Pakdel

    2015-04-01

    Full Text Available Background and Aim: The ability to predict antigenic sites on proteins is of major importance for medication. The aim of this study was to predict the antigenic sites on Agglutin in Like Sequence (ALS1 and Hyphal Wall Protein Sequences (HWP1 in Candida albicans isolated of vaginal infections using Physico-Chemical Profiles server. Materials and Methods: 7 isolates were obtained from women with vaginal infection which were collected from various medical centers of Tehran in 2011 and 2012. At the first,DNA was extracted  by Phenol-Chloroform method. Multiplex PCR was performed by using specific primers. In order to do bioinformatic studies, the genes were sequenced and then translated. Antigenic sites of protein sequences were identified by Physico-Chemical Profiles program. Results: The results showed that the presence of two genes als1 and hwp1 in isolates. In ALS1 and HWP1, respectively 2 and 1 antigenic site with the most antigenicity were identified. Conclusions: According to previous studies, Serine and Threonine phosphorylation is an important mechanism in pathogenesis of ALS1 and HWP1 proteins. Results in this study showed that serine and threonine are the most amino acids in the antigenic sites with high antigenicity property.

  11. A core filamentation response network in Candida albicans is restricted to eight genes.

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    Ronny Martin

    Full Text Available Although morphological plasticity is a central virulence trait of Candida albicans, the number of filament-associated genes and the interplay of mechanisms regulating their expression remain unknown. By correlation-based network modeling of the transcriptional response to different defined external stimuli for morphogenesis we identified a set of eight genes with highly correlated expression patterns, forming a core filamentation response. This group of genes included ALS3, ECE1, HGT2, HWP1, IHD1 and RBT1 which are known or supposed to encode for cell- wall associated proteins as well as the Rac1 guanine nucleotide exchange factor encoding gene DCK1 and the unknown function open reading frame orf19.2457. The validity of network modeling was confirmed using a dataset of advanced complexity that describes the transcriptional response of C. albicans during epithelial invasion as well as comparing our results with other previously published transcriptome studies. Although the set of core filamentation response genes was quite small, several transcriptional regulators are involved in the control of their expression, depending on the environmental condition.

  12. Multi-species biofilm of Candida albicans and non-Candida albicans Candida species on acrylic substrate

    Directory of Open Access Journals (Sweden)

    Apurva K Pathak

    2012-02-01

    Full Text Available OBJECTIVE: In polymicrobial biofilms bacteria extensively interact with Candida species, but the interaction among the different species of the Candida is yet to be completely evaluated. In the present study, the difference in biofilm formation ability of clinical isolates of four species of Candida in both single-species and multi-species combinations on the surface of dental acrylic resin strips was evaluated. MATERIAL AND METHODS: The species of Candida, isolated from multiple species oral candidiasis of the neutropenic patients, were used for the experiment. Organisms were cultured on Sabouraud dextrose broth with 8% glucose (SDB. Biofilm production on the acrylic resins strips was determined by crystal violet assay. Student's t-test and ANOVA were used to compare in vitro biofilm formation for the individual species of Candida and its different multi-species combinations. RESULTS: In the present study, differences between the mean values of the biofilm-forming ability of individual species (C. glabrata>C. krusei>C. tropicalis>C. albicans and in its multi-species' combinations (the highest for C. albicans with C. glabrata and the lowest for all the four species combination were reported. CONCLUSIONS: The findings of this study showed that biofilm-forming ability was found greater for non-Candida albicans Candida species (NCAC than for C. albicans species with intra-species variation. Presence of C. albicans in multi-species biofilms increased, whereas; C. tropicalis decreased the biofilm production with all other NCAC species.

  13. Genome-wide functional analysis in Candida albicans

    Science.gov (United States)

    Motaung, Thabiso E.; Ells, Ruan; Pohl, Carolina H.; Albertyn, Jacobus; Tsilo, Toi J.

    2017-01-01

    ABSTRACT Candida albicans is an important etiological agent of superficial and life-threatening infections in individuals with compromised immune systems. To date, we know of several overlapping genetic networks that govern virulence attributes in this fungal pathogen. Classical use of deletion mutants has led to the discovery of numerous virulence factors over the years, and genome-wide functional analysis has propelled gene discovery at an even faster pace. Indeed, a number of recent studies using large-scale genetic screens followed by genome-wide functional analysis has allowed for the unbiased discovery of many new genes involved in C. albicans biology. Here we share our perspectives on the role of these studies in analyzing fundamental aspects of C. albicans virulence properties. PMID:28277904

  14. Psd1 Effects on Candida albicans Planktonic Cells and Biofilms.

    Science.gov (United States)

    Gonçalves, Sónia; Silva, Patrícia M; Felício, Mário R; de Medeiros, Luciano N; Kurtenbach, Eleonora; Santos, Nuno C

    2017-01-01

    Candida albicans is an important human pathogen, causing opportunistic infections. The adhesion of planktonic cells to a substrate is the first step for biofilm development. The antimicrobial peptide (AMP) Ps d1 is a defensin isolated from Pisum sativum seeds. We tested the effects of this AMP on C. albicans biofilms and planktonic cells, comparing its activity with amphotericin B and fluconazole. Three C. albicans variants were studied, one of them a mutant deficient in glucosylceramide synthase, conferring resistance to Ps d1 antifungal action. Atomic force microscopy (AFM) was used to assess morphological and biomechanical changes on fungal cells. Surface alterations, with membrane disruption and leakage of cellular contents, were observed. Cytometry assays and confocal microscopy imaging showed that Ps d1 causes cell death, in a time and concentration-dependent manner. These results demonstrate Ps d1 pleiotropic action against a relevant fungal human pathogen, suggesting its use as natural antimycotic agent.

  15. [Adhesion of clinical Candida albicans isolate to buccal epithelial cells].

    Science.gov (United States)

    Wellmer, A

    1999-01-01

    Mucosal adherence and germ tube formation are considered to be important virulence factors of C. albicans. Adherence is a precondition for colonisation and invasion. We investigated 11 clinical isolates (among them 5 cases recovered from oesophageal thrush) for quantification of the two characteristics and correlated the results with clinical data. Adherence was measured on buccal epithelial cells and the continuous flow culture was used for quantification of germ tube formation. Adherence of strains recovered from clinically, culturally and serologically confirmed oesophageal thrush adhered stronger to buccal epithelial cells than isolates from patients with heavy colonisation without signs of candidosis. Strains with stronger adherence showed a significantly faster and an increased germ tube formation in the continuous flow culture. Strains from oesophageal thrush therefore show a more marked expression of the investigated virulence factors. Therefore a good adherence is a necessity for infection of the oesophagus by C. albicans. The preferential isolation of C. albicans from oesophageal thrush (> 90%) supports this assumption.

  16. Oral candidiasis-adhesion of non-albicans Candida species

    Directory of Open Access Journals (Sweden)

    Bokor-Bratić Marija B.

    2008-01-01

    Full Text Available Oral candidiasis is an opportunistic infection caused primarily by Candida albicans. However, in recent years, species of non-albicans Candida have been implicated more frequently in mucosal infection. Candida species usually reside as commensal organisms and are part of normal oral microflora. Determining exactly how transformation from commensal to pathogen takes place and how it can be prevented is continuous challenge for clinical doctors. Candidal adherence to mucosal surfaces is considered as a critical initial step in the pathogenesis of oral candidiasis. Acrylic dentures, acting as reservoirs, play an important role in increasing the risk from Candida colonisation. Thus, this review discusses what is currently known about the adhesion of non-albicans Candida species of oral origin to buccal epithelial cells and denture acrylics.

  17. The expression of genes involved in the ergosterol biosynthesis pathway in Candida albicans and Candida dubliniensis biofilms exposed to fluconazole.

    LENUS (Irish Health Repository)

    2009-03-01

    The expression of the ERG1, ERG3, ERG7, ERG9, ERG11 and ERG25 genes in response to incubation with fluconazole and biofilm formation was investigated using reverse-transcription PCR and real-time PCR in Candida albicans and Candida dubliniensis clinical isolates. The viability of biofilm was measured using an 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay and confocal scanning laser microscopy (CSLM). Expression of the ERG11 gene was found to be low or moderate and it was regulated by fluconazole addition more so than by biofilm formation. Very low or non-detectable expression of ERG1, ERG7 and ERG25 genes was detected in C. albicans. The expression of the ERG9 increased in the presence of fluconazole in some isolates. Following incubation with fluconazole, formation of biofilm by C. dubliniensis was coupled with up-regulation of the ERG3 and ERG25 genes as have been observed previously in C. albicans. Planktonic cells of both Candida species released from biofilm displayed similar resistance mechanisms to fluconazole like attached cells. The XTT reduction assay and CSLM revealed that although incubation with fluconazole decreased the biofilm thickness, these were still comprised metabolically active cells able to disseminate and produce biofilm. Our data indicate that biofilm represents a highly adapted community reflecting the individuality of clinical isolates.

  18. Invasive candidiasis in intensive care units in China: Risk factors and prognoses of Candida albicans and non-albicans Candida infections.

    Science.gov (United States)

    Gong, Xiaoying; Luan, Ting; Wu, Xingmao; Li, Guofu; Qiu, Haibo; Kang, Yan; Qin, Bingyu; Fang, Qiang; Cui, Wei; Qin, Yingzhi; Li, Jianguo; Zang, Bin

    2016-05-01

    To investigate the risk factors and prognoses of patients with invasive Candida albicans and non-albicans Candida (NAC) infection in intensive care units (ICUs) in China. Between November 2009 and April 2011, we performed a prospective study of critically ill patients with invasive Candida infection from 67 ICUs across China to compare the risk factors and mortality between patients with C albicans and NAC infection. There were 306 patients with proven invasive Candida; 244 cases (a total 389 Candida isolates) were sent to laboratory for strain identification (C albicans, 40.1%; NAC, 59.9%). More patients admitted for surgery or trauma had NAC infection than C albicans infection. C albicans infection was more common in patients with subclavian vein catheters or peritoneal drainage tubes. Compared with patients with C albicans infection, patients with NAC infection had longer antifungal therapy (P albicans remains the most common pathogen in candidiasis in critical care patients. However, the number of NAC infections exceeded C albicans infections. Compared with patients with C albicans infection, patients with NAC infection had heavier disease burdens. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  19. In vitro evaluation of antifungal activity of monolaurin against Candida albicans biofilms

    Directory of Open Access Journals (Sweden)

    Dalia Seleem

    2016-06-01

    Full Text Available Monolaurin (also known as glycerol monolaurate is a natural compound found in coconut oil and is known for its protective biological activities as an antimicrobial agent. The nature of oral candidiasis and the increased antifungal resistance demand the search for novel antifungal therapeutic agents. In this study, we examine the antifungal activity of monolaurin against Candida albicans biofilms (strain ATCC:SC5314/MYA2876 in vitro and investigate whether monolaurin can alter gene expression of host inflammatory cytokines, IL-1α and IL-1β. In a co-culture model, oral fibroblast cells were cultured simultaneously with C. albicans for 24 hrs followed by the exposure to treatments of monolaurin (3.9–2,500 µM, positive control fluconazole (32.2 µM, and vehicle control group (1% ethanol, which was a model used to evaluate the cytotoxicity of monolaurin on fibroblasts as well as to analyze morphological characteristics of biofilms through fluorescence microscopy. In addition, the co-culture model was used for RNA extraction of oral fibroblasts to assess gene expression of host inflammatory cytokines, using quantitative real-time PCR. Our results showed the MIC and MFC of monolaurin were in the range 62.5–125 µM and 125–250 µM, respectively. Biofilm antifungal assay showed significant reduction in Log (CFU/ml of biofilms treated with 1,250 and 2,500 µM of 1-monolaurin when compared to the control groups . There was also a significant down-regulation of IL-1α and IL-1β in the co-culture treated with monolaurin. It can be concluded that monolaurin has a potential antifungal activity against C. albicans and can modulate the pro-inflammatory response of the host.

  20. In vitro evaluation of antifungal activity of monolaurin against Candida albicans biofilms.

    Science.gov (United States)

    Seleem, Dalia; Chen, Emily; Benso, Bruna; Pardi, Vanessa; Murata, Ramiro M

    2016-01-01

    Monolaurin (also known as glycerol monolaurate) is a natural compound found in coconut oil and is known for its protective biological activities as an antimicrobial agent. The nature of oral candidiasis and the increased antifungal resistance demand the search for novel antifungal therapeutic agents. In this study, we examine the antifungal activity of monolaurin against Candida albicans biofilms (strain ATCC:SC5314/MYA2876) in vitro and investigate whether monolaurin can alter gene expression of host inflammatory cytokines, IL-1α and IL-1β. In a co-culture model, oral fibroblast cells were cultured simultaneously with C. albicans for 24 hrs followed by the exposure to treatments of monolaurin (3.9-2,500 µM), positive control fluconazole (32.2 µM), and vehicle control group (1% ethanol), which was a model used to evaluate the cytotoxicity of monolaurin on fibroblasts as well as to analyze morphological characteristics of biofilms through fluorescence microscopy. In addition, the co-culture model was used for RNA extraction of oral fibroblasts to assess gene expression of host inflammatory cytokines, using quantitative real-time PCR. Our results showed the MIC and MFC of monolaurin were in the range 62.5-125 µM and 125-250 µM, respectively. Biofilm antifungal assay showed significant reduction in Log (CFU/ml) of biofilms treated with 1,250 and 2,500 µM of 1-monolaurin when compared to the control groups . There was also a significant down-regulation of IL-1α and IL-1β in the co-culture treated with monolaurin. It can be concluded that monolaurin has a potential antifungal activity against C. albicans and can modulate the pro-inflammatory response of the host.

  1. Synergistic Interactions of Eugenol-tosylate and Its Congeners with Fluconazole against Candida albicans.

    Directory of Open Access Journals (Sweden)

    Aijaz Ahmad

    Full Text Available We previously reported the antifungal properties of a monoterpene phenol "Eugenol" against different Candida strains and have observed that the addition of methyl group to eugenol drastically increased its antimicrobial potency. Based on the results and the importance of medicinal synthetic chemistry, we synthesized eugenol-tosylate and its congeners (E1-E6 and tested their antifungal activity against different clinical fluconazole (FLC- susceptible and FLC- resistant C. albicans isolates alone and in combination with FLC by determining fractional inhibitory concentration indices (FICIs and isobolograms calculated from microdilution assays. Minimum inhibitory concentration (MIC results confirmed that all the tested C. albicans strains were variably susceptible to the semi-synthetic derivatives E1-E6, with MIC values ranging from 1-62 μg/ml. The test compounds in combination with FLC exhibited either synergy (36%, additive (41% or indifferent (23% interactions, however, no antagonistic interactions were observed. The MICs of FLC decreased 2-9 fold when used in combination with the test compounds. Like their precursor eugenol, all the derivatives showed significant impairment of ergosterol biosynthesis in all C. albicans strains coupled with down regulation of the important ergosterol biosynthesis pathway gene-ERG11. The results were further validated by docking studies, which revealed that the inhibitors snugly fitting the active site of the target enzyme, mimicking fluconazole, may well explain their excellent inhibitory activity. Our results suggest that these compounds have a great potential as antifungals, which can be used as chemosensitizing agents with the known antifungal drugs.

  2. A radiolabel release microassay for phagocytic killing of Candida albicans

    International Nuclear Information System (INIS)

    Bistoni, F.; Baccarini, M.; Blasi, E.; Marconi, P.; Puccetti, P.

    1982-01-01

    The chromium-51 release technique for quantifying intracellular killing of radiolabelled Candida albicans particles was exploited in a microassay in which murine and human phagocytes acted as effectors under peculiarly simple conditions. At appropriate effector: target ratios and with a 4 h incubation, up to 50% specific chromium release could be detected in the supernatant with no need for opsonization or lysis of phagocytes. This simple microassay permits easy-to-perform, simultaneous testing of a variety of different phagocytes even if only available in limited amounts, and provides an objective measurement of intracellular killing of Candida albicans. (Auth.)

  3. Actin and phosphoinositide recruitment to fully formed Candida albicans phagosomes in mouse macrophages

    NARCIS (Netherlands)

    Heinsbroek, Sigrid E. M.; Kamen, Lynn A.; Taylor, Philip R.; Brown, Gordon D.; Swanson, Joel; Gordon, Siamon

    2009-01-01

    Candida albicans is a dimorphic yeast that enters macrophages (Mphi) via the beta-glucan receptor dectin-1. Phagocytosis of C. albicans is characterized by actin polymerization, Syk kinase activation and rapid acquisition of phagolysosomal markers. In mice, C. albicans are able to resist the harsh

  4. Variable recognition of Candida albicans strains by TLR4 and lectin recognition receptors.

    NARCIS (Netherlands)

    Netea, M.G.; Gow, N.A.; Joosten, L.A.B.; Verschueren, I.; Meer, J.W.M. van der; Kullberg, B.J.

    2010-01-01

    The role of TLR4 in the recognition of Candida albicans has been brought into question. In order to assess whether discrepancies in the literature are due to differences in the recognition of various C. albicans strains, we selected 14 different isolates of C. albicans to evaluate their recognition

  5. Mutational analysis of metacaspase CaMca1 and decapping activator Edc3 in the pathogenicity of Candida albicans.

    Science.gov (United States)

    Jeong, Jeong-Hoon; Lee, Seok-Eui; Kim, Jinmi

    2016-12-01

    Candida albicans, an opportunistic fungal pathogen, displays apoptotic cell death in response to various stresses and a wide range of antifungal treatments. CaMca1, which is the only metacaspase in C. albicans, has been described as a key player in apoptotic cell death. Edc3 is an mRNA decapping activator and a scaffold protein of processing bodies. Edc3 was previously shown to regulate CaMCA1 expression and oxidative stress-induced apoptosis. In this study, we analyzed the contribution of the catalytic residues of the CaMca1 to the oxidative stress-induced apoptosis and pathogenicity of C. albicans. The CaMCA1 C292A mutation decreased caspase activity to a level similar to that observed in the Camca1/Camca1 deletion strain and over-expression of CaMCA1 C292A failed to suppress the oxidative-stress phenotypes of the edc3/edc3 mutant strain. The edc3/edc3, Camca1/Camca1, and CaMCA1 C292A mutant strains were not virulent in a murine candidiasis model. Filamentation defects were observed in the Camca1/Camca1 mutant cells, whereas this defect was only partial in CaMCA1 C292A mutant cells. These results suggest that CaMca1 and Edc3 play essential roles in the oxidative stress-induced apoptosis and virulence of C. albicans, and also support the notion that Edc3 is a key regulator of CaMca1 expression. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Enhanced hyphal growth of arbuscular mycorrhizae by root exudates derived from high R/FR treated Lotus japonicus.

    Science.gov (United States)

    Nagata, Maki; Yamamoto, Naoya; Miyamoto, Taro; Shimomura, Aya; Arima, Susumu; Hirsch, Ann M; Suzuki, Akihiro

    2016-06-02

    Red/Far Red (R/FR) sensing positively influences the arbuscular mycorrhizal (AM) symbiosis of both legume and nonlegume plants through jasmonic acid (JA) and strigolactone signaling. We previously reported that root exudates obtained from high R/FR-grown plants contained more strigolactone than low R/FR-grown plants. To determine whether JA and JA derivatives were secreted from roots, we investigated the expression levels of JA-responsive genes in L. japonicus Miyakojima MG20 plants treated with root exudates prepared from either high or low R/FR light-treated plants. The root exudates from high R/FR light-treated plants were found to enhance the expression levels of JA-responsive genes significantly. Moreover, exogenous JA increased AM fungal hyphal elongation as did the root exudates derived from high R/FR-grown L. japonicus plants. We conclude that increased JA accumulation and secretion into root exudates from high R/FR light-grown plants is the best explanation for increased colonization and enhanced mycorrhization under these conditions.

  7. Defective IL-17- and IL-22-dependent mucosal host response to Candida albicans determines susceptibility to oral candidiasis in mice expressing the HIV-1 transgene.

    Science.gov (United States)

    Goupil, Mathieu; Cousineau-Côté, Vincent; Aumont, Francine; Sénéchal, Serge; Gaboury, Louis; Hanna, Zaher; Jolicoeur, Paul; de Repentigny, Louis

    2014-10-26

    The tissue-signaling cytokines IL-17 and IL-22 are critical to host defense against oral Candida albicans infection, by their induction of oral antimicrobial peptide expression and recruitment of neutrophils. Mucosal Th17 cells which produce these cytokines are preferentially depleted in HIV-infected patients. Here, we tested the hypothesis that defective IL-17- and IL-22-dependent host responses to C. albicans determine the phenotype of susceptibility to oropharyngeal candidiasis (OPC) in transgenic (Tg) mice expressing HIV-1. Naïve CD4+ T-cells and the differentiated Th1, Th2, Th17, Th1Th17 and Treg lineages were all profoundly depleted in cervical lymph nodes (CLNs) of these Tg mice. However, naive CD4+ cells from Tg mice maintained the capacity to differentiate into these lineages in response to polarizing cytokines in vitro. Expression of Il17, Il22, S100a8 and Ccl20 was enhanced in oral mucosal tissue of non-Tg, but not of Tg mice, after oral infection with C. albicans. Treatment of infected Tg mice with the combination of IL-17 and IL-22, but not IL-17 or Il-22 alone, significantly reduced oral burdens of C. albicans and abundance of Candida hyphae in the epithelium of tongues of infected Tg mice, and restored the ability of the Tg mice to up-regulate expression of S100a8 and Ccl20 in response to C. albicans infection. These findings demonstrate that defective IL-17- and IL-22-dependent induction of innate mucosal immunity to C. albicans is central to the phenotype of susceptibility to OPC in these HIV transgenic mice.

  8. Phosphomannosylation and the Functional Analysis of the Extended Candida albicans MNN4-Like Gene Family

    Directory of Open Access Journals (Sweden)

    Roberto J. González-Hernández

    2017-11-01

    Full Text Available Phosphomannosylation is a modification of cell wall proteins that occurs in some species of yeast-like organisms, including the human pathogen Candida albicans. These modified mannans confer a negative charge to the wall, which is important for the interactions with phagocytic cells of the immune systems and cationic antimicrobial peptides. In Saccharomyces cerevisiae, the synthesis of phosphomannan relies on two enzymes, the phosphomannosyltransferase Ktr6 and its positive regulator Mnn4. However, in C. albicans, at least three phosphomannosyltransferases, Mnn4, Mnt3 and Mnt5, participate in the addition of phosphomannan. In addition to MNN4, C. albicans has a MNN4-like gene family composed of seven other homologous members that have no known function. Here, using the classical mini-Ura-blaster approach and the new gene knockout CRISPR-Cas9 system for gene disruption, we generated mutants lacking single and multiple genes of the MNN4 family; and demonstrate that, although Mnn4 has a major impact on the phosphomannan content, MNN42 was also required for full protein phosphomannosylation. The reintroduction of MNN41, MNN42, MNN46, or MNN47 in a genetic background lacking MNN4 partially restored the phenotype associated with the mnn4Δ null mutant, suggesting that there is partial redundancy of function between some family members and that the dominant effect of MNN4 over other genes could be due to its relative abundance within the cell. We observed that additional copies of alleles number of any of the other family members, with the exception of MNN46, restored the phosphomannan content in cells lacking both MNT3 and MNT5. We, therefore, suggest that phosphomannosylation is achieved by three groups of proteins: [i] enzymes solely activated by Mnn4, [ii] enzymes activated by the dual action of Mnn4 and any of the products of other MNN4-like genes, with exception of MNN46, and [iii] activation of Mnt3 and Mnt5 by Mnn4 and Mnn46. Therefore

  9. POTENSI ANTIFUNGI TANGKAI DAUN JARAK PAGAR TERHADAP PERTUMBUHAN Candida albicans

    Directory of Open Access Journals (Sweden)

    Ni Made Niagita Wiratni

    2017-12-01

    Full Text Available Tangkai daun Jarak pagar merupakan bagian dari Jarak pagar yang bisa dimanfaatkan sebagai pengobatan herbal oleh masyarakat untuk mengatasi masalah keputihan. Keputihan adalah gejala yang umum dialami oleh sebagian besar wanita yang disebabkan oleh infeksi Candida albicans. Penelitian ini eksperimen murni dengan desain kontrol posttest yang bertujuan untuk mengetahui kandungan fitokimia dan potensi antijamur ekstrak tangkai daun jarak pagar terhadap pertumbuhan Candida albicans. Ekstrak tangkai daun jarak pagar dalam penelitian ini diperoleh melalui proses ekstraksi pelarut dengan menggunakan etanol 96% dengan metode maserasi. Metode yang digunakan untuk uji fitokimia adalah metode kualitatif, sedangkan untuk uji potensi antijamur dilakukan dengan metode difusi dengan konsentrasi 10%, 25%, 30%, 40% dan 50%. Hasil uji fitokimia menunjukkan bahwa ekstrak tangkai daun jarak pagar mengandung saponin, tanin, dan flavonoid, namun tidak ditemukan senyawa alkaloid, namun hasil uji potensi antijamur menunjukkan bahwa diameter rata-rata zona inhibisi terhadap pertumbuhan Candida albicans adalah 0 mm . Kesimpulan dari penelitian ini adalah ekstrak tangkai daun jarak pagar tidak dapat menghambat pertumbuhan Candida albicans. Peneliti selanjutnya disarankan untuk melakukan uji fitokimia secara kuantitatif dan untuk menguji potensi antijamur tangkai daun jarak pagar dengan metode pengenceran.

  10. Antimicrobial Activity of Five Medicinal Plants on Candida Albicans

    Directory of Open Access Journals (Sweden)

    Fatemeh Masomi

    2016-10-01

    Full Text Available Background: In recent years, drug resistance to human pathogenic fungi has been increased. Medicinal plants are one way to overcome antibiotic resistance. The aim of this study was to evaluate the antifungal and inhibitory activity of five medicinal plants on the growth of Candida albicans. Methods: This study was done in the Microbiology Lab of Shahid Bahonar University of Kerman, Iran in 2015. Five medicinal plants include: Trachyspermum ammi (seed, Teucrium polium (leaf, Piper nigrum (seed, Pistachia vera (skin, Camelia sinensis (leaf were collected. Collected plant materials were extracted by ethanol and methanol solvent with maceration method. Antifungal activity of the ethanolic and methanolic extracts was evaluated by paper disc diffusion and agar well diffusion methods. Besides, MIC and MBC of each extract was determined. Results: All plant extracts had sufficient inhibitory effect against C. albicans but the extracts of P. vera had the best inhibitory effect on C. albicans (ZOI: 40 mm. The lowest antifungal effect between these five plants related to Piper nigrum (ZOI: 13 mm. Besides, the P. vera extracts had the best MIC and MBC values (6.25 and 12.5 mg/ml. Conclusion: This study strongly evidence the maximum antimicrobial activity of medicinal plants against C. albicans that this inhibitory effect varies with the different solvent-extract form. A more comprehensive study need to identify the effective compounds that have these antifungal properties.

  11. Incidence Of Candida Albicans Infection Among Women Having ...

    African Journals Online (AJOL)

    Objectives: This work was carried out to ascertain the incidence of candida albicans among women in Anambra State. Design: High vaginal swab (HVS) samples were collected from women that attend six hospitals in Anambra State between the months of June and September 2006. Settings: The samples were collected ...

  12. Evaluation of Candida Albicans Biofilm Formation on Various Dental ...

    African Journals Online (AJOL)

    2016-06-24

    Jun 24, 2016 ... Aims: Candida adhesion to any oral substrata is the first and essential stage in ... in the oral cavity of 20-40% of healthy individuals[1] .... colonizing bacteria.[24] Higher numbers of C. albicans are found on rough surfaces than on polished, smooth surfaces.[25] Theoretically, and as a consequence, dental.

  13. PERTUMBUHAN CANDIDA ALBICANS PADA PERMUKAAN POLIESTER EBP-2421

    Directory of Open Access Journals (Sweden)

    Widowati Siswomihardjo

    2015-08-01

    Full Text Available Acrylic resin has been the only polymeric material for denture base for many years. One of the requirements for an ideal polymeric denture base material. It should be resistant to bacterial growth. The growth of Candida albicans on the surface of dentures is a concern for many denture wearers. This organism often is associated with denture stomatitis. A preliminary study showed polyester EBP-2421, a polymeric material for statues can also be manipulated to denture base. This research examined the growth of Candida albicans on the surface of EBP-2421. Research was carried out on strips of polyester EBP-2421 and Selton acrylic resin. Strips were contaminated with Candida albicans for 24 hours. Examinations on polyester EBP-2421 and acrylic resin immersed in saliva significantly differ from the not immersed strips (p<0,05. The lowest frequency were Candida albicans adhered on stripes of polyester EBP-2421 immersed in saliva. This result related with the fact that polyester EBP-2421 has smoother surface topography than acrylic resin.

  14. CandidaDB: a genome database for Candida albicans pathogenomics.

    Science.gov (United States)

    d'Enfert, C; Goyard, S; Rodriguez-Arnaveilhe, S; Frangeul, L; Jones, L; Tekaia, F; Bader, O; Albrecht, Antje; Castillo, L; Dominguez, A; Ernst, J F; Fradin, C; Gaillardin, C; Garcia-Sanchez, S; de Groot, P; Hube, B; Klis, F M; Krishnamurthy, S; Kunze, D; Lopez, M-C; Mavor, A; Martin, N; Moszer, I; Onésime, D; Perez Martin, J; Sentandreu, R; Valentin, E; Brown, A J P

    2005-01-01

    CandidaDB is a database dedicated to the genome of the most prevalent systemic fungal pathogen of humans, Candida albicans. CandidaDB is based on an annotation of the Stanford Genome Technology Center C.albicans genome sequence data by the European Galar Fungail Consortium. CandidaDB Release 2.0 (June 2004) contains information pertaining to Assembly 19 of the genome of C.albicans strain SC5314. The current release contains 6244 annotated entries corresponding to 130 tRNA genes and 5917 protein-coding genes. For these, it provides tentative functional assignments along with numerous pre-run analyses that can assist the researcher in the evaluation of gene function for the purpose of specific or large-scale analysis. CandidaDB is based on GenoList, a generic relational data schema and a World Wide Web interface that has been adapted to the handling of eukaryotic genomes. The interface allows users to browse easily through genome data and retrieve information. CandidaDB also provides more elaborate tools, such as pattern searching, that are tightly connected to the overall browsing system. As the C.albicans genome is diploid and still incompletely assembled, CandidaDB provides tools to browse the genome by individual supercontigs and to examine information about allelic sequences obtained from complementary contigs. CandidaDB is accessible at http://genolist.pasteur.fr/CandidaDB.

  15. Role of IFN-gamma in immune responses to Candida albicans infections.

    Science.gov (United States)

    Gozalbo, Daniel; Maneu, Victoria; Gil, María Luisa

    2014-06-01

    Candida albicans is the most frequent etiologic agent that causes opportunistic fungal infections called candidiasis, a disease whose systemic manifestation could prove fatal and whose incidence is increasing as a result of an expanding immunocompromised population. Here we review the role of interferon-gamma (IFN-gamma) in host protection against invasive candidiasis. This cytokine plays an essential role in both the innate and adaptive arms of the immune response to candidiasis. We focus on recent progress on host-pathogen interactions leading to the production of IFN-gamma by host cells. IFN-gamma is produced by CD4 Th1, CD8, gamma delta T, and natural killer (NK) cells, essentially in response to both IL-12 and/or IL-18; more recently, a subset of C. albicans -specific Th17 cells have been described to produce both IL-17 and IFN-gamma. IFN-gamma plays an important role in the regulation of the immune system as well as in the control of the infectious process, as it is required for optimal activation of phagocytes, collaborates in the generation of protective antibody response, and favors the development of a Th1 protective response.

  16. Linalool-induced oxidative stress processes in the human pathogen Candida albicans.

    Science.gov (United States)

    Máté, Gábor; Kovács, Dominika; Gazdag, Zoltán; Pesti, Miklós; Szántó, Árpád

    2017-06-01

    The present study investigated the linalool (Lol)-induced effects in acute toxicity tests in the human pathogen Candida albicans (C. albicans). Lol treatments induced reduced germ tube formation of the pathogen, which plays a crucial role in the virulence. In comparison with the untreated control, the exposure of 107 cells ml -1 to 0.7 mM or 1.4 mM Lol for one hour induced 20% and 30% decrements, respectively, in the colony-forming ability. At the same time, these treatments caused dose-dependent decrease in the levels of superoxide anion radical and total reactive oxygen species, while there was 1.5 and 1.8-fold increases in the concentrations of peroxides and lipid peroxides, respectively, indicating oxidative stress induction in the presence of Lol. Lol treatments resulted in different adaptive modifications of the antioxidant system. In 0.7 mM-treated cells, decreased specific activities of superoxide dismutase and catalase were detected, while exposure to 1.4 mM Lol resulted in the up-regulation of catalase, glutathione reductase and glutathione peroxidases.

  17. The Role of IL-33 in Host Response to Candida albicans

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    C. Rodríguez-Cerdeira

    2014-01-01

    Full Text Available Background. Interleukin (IL 33 is a recently identified pleiotropic cytokine that influences the activity of multiple cell types and orchestrates complex innate and adaptive immune responses. Methods. We performed an extensive review of the literature published between 2005 and 2013 on IL-33 and related cytokines, their functions, and their regulation of the immune system following Candida albicans colonization. Our literature review included cross-references from retrieved articles and specific data from our own studies. Results. IL-33 (IL-1F11 is a recently identified member of the IL-1 family of cytokines. Accumulating evidence suggests a pivotal role of the IL-33/ST2 axis in host immune defense against fungal pathogens, including C. albicans. IL-33 induces a Th2-type inflammatory response and activates both innate and adaptive immunity. Studies in animal models have shown that Th2 inflammatory responses have a beneficial role in immunity against gastrointestinal and systemic infections by Candida spp. Conclusions. This review summarizes the most important clinical studies and case reports describing the beneficial role of IL-33 in immunity and host defense mechanisms against pathogenic fungi. The finding that the IL-33/ST2 axis is involved in therapeutic target has implications for the prevention and treatment of inflammatory diseases, including acute or chronic candidiasis.

  18. Synergistic Effect of Fluconazole and Calcium Channel Blockers against Resistant Candida albicans.

    Directory of Open Access Journals (Sweden)

    Shuyuan Liu

    Full Text Available Candidiasis has increased significantly recently that threatens patients with low immunity. However, the number of antifungal drugs on the market is limited in comparison to the number of available antibacterial drugs. This fact, coupled with the increased frequency of fungal resistance, makes it necessary to develop new therapeutic strategies. Combination drug therapy is one of the most widely used and effective strategy to alleviate this problem. In this paper, we were aimed to evaluate the combined antifungal effects of four CCBs (calcium channel blockers, amlodipine (AML, nifedipine (NIF, benidipine (BEN and flunarizine (FNZ with fluconazole against C. albicans by checkerboard and time-killing method. In addition, we determined gene (CCH1, MID1, CNA1, CNB1, YVC1, CDR1, CDR2 and MDR1 expression by quantitative PCR and investigated the efflux pump activity of resistant candida albicans by rhodamine 6G assay to reveal the potential mechanisms. Finally, we concluded that there was a synergy when fluconazole combined with the four tested CCBs against resistant strains, with fractional inhibitory concentration index (FICI <0.5, but no interaction against sensitive strains (FICI = 0.56 ~ 2. The mechanism studies revealed that fluconazole plus amlodipine caused down-regulating of CNA1, CNB1 (encoding calcineurin and YVC1 (encoding calcium channel protein in vacuole membrane.

  19. Iron-dependency of biological properties of Candida albicans

    Directory of Open Access Journals (Sweden)

    V. V. Leonov

    2017-01-01

    Full Text Available Background: Candidal infections occur in individuals with humoral or cell immunity deficiency. Any disorders of iron metabolism promote immune deficiency and abnormal sensitivity to infections. Potential modification of biological properties of Candida spp. in disorders of iron metabolism has not been discussed. Aim: To clarify the effects of iron metabolism disorders on the modification of biological properties of C.  albicans. Materials and methods: Growth kinetics of reference strain (24433 АТСС and clinical isolates of C.  albicans (n=20 depending on the concentration of Fe2+ ions in the broth and serum of blood donors with various types of iron metabolism (n=2 was studied by turbidimetry. We also assessed the expression of the adhesion gen (als3, hemolytic phospholipase C genes (plb1, plb2, plс and aspartic protease gene (sap1 in serum of donors with various iron levels. Results: Growth parameters of all C. albicans strains studied depends on the iron levels in the medium. The calculated constant of affinity to Fe2+ (Ks for C. albicans strains was in the range from 179.5 to 1863.3 μM. Clinical isolates are more iron-dependent (179.5albicans and is associated with overexpression of all virulence genes studied. Incubation of C.  albicans with iron-deficient and iron-loaded sera results in an increase in the growth rate up to 0.017 h-1 and 0.012 h-1, respectively, but is associated with a  reduction in expression of the major virulence genes. Conclusion: Biological properties of C. albicans are modified depending on the iron metabolism of the host. In those with normal iron metabolism, immune system suppresses Candida growth. Excess iron levels may promote candidiasis, whereas in iron

  20. Direct bioethanol production by amylolytic yeast Candida albicans.

    Science.gov (United States)

    Aruna, A; Nagavalli, M; Girijashankar, V; Ponamgi, S P D; Swathisree, V; Rao, L Venkateswar

    2015-03-01

    An attempt was made to produce bioethanol using optimized fermentation parameters and mutationally improved strain of Candida albicans. The mutant strain OMC3E6 obtained by UV irradiation followed by ethidium bromide successive mutations showed 2.6 times more glucoamylase secretion and 1.5 times more bioethanol production via direct conversion of starch. Enhanced hydrolysis of insoluble starch (72%) and potato starch (70%) was achieved with glucoamylase enzyme preparation from mutant C. albicans. In fermentation medium, the use of maltose, corn steep liquor, NaH2 PO4 , NaCl + MgSO4 and Triton X-100 has increased the glucoamylase production by the microbe. Under optimized conditions, C. albicans eventually produced 437 g ethanol kg(-1) potatoes. Earlier reports mentioned the use of thrice the quantity of starch as reported by us followed by more fermentation period (3-4 days) and demanded pretreatment of starch sources with alpha-amylase as well. Here, we simplified these three steps and obtained 73% conversion of insoluble starch into ethanol via direct conversion method in a period of 2 days without the involvement of cell immobilizations or enzyme pretreatment steps. Due to fast depletion of fossil fuels in the modern world, bioethanol usage as an alternate energy source is the need of the hour. For the first time, we report bioethanol production by Candida albicans via direct conversion of starchy biomass into ethanol along with enhanced starch-hydrolysing capacity and ethanol conversion ratio. So far, C. albicans was dealt in the field of clinical pathology, but here we successfully employed this organism to produce bioethanol from starchy agri-substrates. Optimizing fermentation parameters and improving the microbial strains through successive mutagenesis can improve the end product yield. © 2014 The Society for Applied Microbiology.

  1. Altered Immune Activation and IL-23 Signaling in Response to Candida albicans in Autoimmune Polyendocrine Syndrome Type 1

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    Øyvind Bruserud

    2017-09-01

    Full Text Available ObjectiveAutoimmune polyendocrine syndrome type 1 (APS-1 is a rare, childhood onset disease caused by mutations in the autoimmune regulator (AIRE gene. Chronic mucocutaneous candidiasis (CMC is one of the three major disease components and is, to date, mainly explained by the presence of neutralizing auto-antibodies against cytokines [interleukin (IL-17A, IL-17F, and IL-22] from T helper 17 cells, which are critical for the protection against fungal infections. However, patients without current auto-antibodies also present CMC and we, therefore, hypothesized that other immune mechanisms contribute to CMC in APS-1.MethodsWhole blood was stimulated with Candida albicans (C. albicans in a standardized assay, and immune activation was investigated by analyzing 46 secreted immune mediators. Then, peripheral blood mononuclear cells were stimulated with curdlan, a Dectin-1 agonist and IL-23 inducer, and the IL-23p19 response in monocytes was analyzed by flow cytometry.ResultsWe found an altered immune response in APS-1 patients compared with healthy controls. Patients fail to increase the essential ILs, such as IL-2, IL-17A, IL-22, and IL-23, when stimulating whole blood with C. albicans. A significantly altered IL-23p19 response was detected in patients’ monocytes upon stimulation with curdlan.ConclusionAPS-1 patients have an altered immune response to C. albicans including a dysregulation of IL-23p19 production in monocytes. This probably contributes to the selective susceptibility to CMC found in the majority of patients.

  2. Photoinactivation of single and mixed biofilms of Candida albicans and non-albicans Candida species using Photodythazine® [corrected].

    Science.gov (United States)

    Carmello, Juliana Cabrini; Alves, Fernanda; Mima, Ewerton Garcia de Oliveira; Jorge, Janaina Habib; Bagnato, Vanderlei Salvador; Pavarina, Ana Cláudia

    2017-03-01

    This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT) mediated by Photodithazine ® (PDZ) formulated in hydrogel, in the inactivation of mono and duo-species biofilms of Candida albicans, Candida glabrata and Candida tropicalis. Standardized suspensions of each strain were prepared and after biofilm formation, mono-species were treated with 150 and 175mg/L of PDZ for 20min (pre-irradiation time), and exposed to LED light at a dose of 37.5J/cm 2 (660nm). The duo-species biofilms (C. albicans+C. glabrata and C. albicans+C. tropicalis) were treated with 150mg/L of PDZ and light. Additional samples were treated with PDZ or light only, and the control did not receive any treatment. Next, microbiological evaluation was performed by spreading the cells on Sabouraud Dextrose Agar and CHROMagar Candida for colony forming units (CFU/mL). Moreover, the total biomass of biofilm was verified using the crystal violet staining assay (CV). The data were submitted to ANOVA and Tukey post-hoc (α=0.05). The use of PDZ 150mg/L promoted a reduction of 1.0, 1.2, 1.5 log 10 in the viability of C. glabrata, C. albicans and C. tropicalis, respectively. The same concentration reduced in 1.0 log 10 the viability of each species grown as duo-species biofilms. The crystal violet assay showed that the use of 150mg/L reduced 24.4%, 39.2% and 43.7% of the total biomass of C. albicans, C. tropicalis and C. glabrata, respectively. aPDT did not reduce the total biomass to the duo-species biofilms. Thus, PDZ-mediated aPDT was more effective in the inactivation of mono-species biofilms of Candida spp. compared with duo-species biofilm. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Compost Addition Enhanced Hyphal Growth and Sporulation of Arbuscular Mycorrhizal Fungi without Affecting Their Community Composition in the Soil

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    Yang, Wei; Gu, Siyu; Xin, Ying; Bello, Ayodeji; Sun, Wenpeng; Xu, Xiuhong

    2018-01-01

    Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most crop plant species in agricultural ecosystems, and are conspicuously influenced by various agricultural practices. To understand the impact of compost addition on AM fungi, we examined effect of four compost rates (0, 11.25, 22.5, and 45 Mg/ha) on the abundance and community composition of AM fungi in seedling, flowering, and mature stage of soybean in a 1-year compost addition experiment system in Northeast China. Soybean [Glycine max (L.) Merrill] was used as test plant. Moderate (22.5 Mg/ha) and high (45 Mg/ha) levels of compost addition significantly increased AM root colonization and extraradical hyphal (ERH) density compared with control, whereas low (11.5 Mg/ha) level of compost addition did not cause significant increase in AM root colonization and ERH density. AM fungal spore density was significantly enhanced by all the compost rates compared with control. The temporal variations analysis revealed that, AM root colonization in seedling stage was significantly lower than in flowering and mature stage. Although AM fungal operational taxonomic unit richness and community composition was unaffected by compost addition, some abundant AM fungal species showed significantly different response to compost addition. In mature stage, Rhizophagus fasciculatum showed increasing trend along with compost addition gradient, whereas the opposite was observed with Paraglomus sp. In addition, AM fungal community composition exhibited significant temporal variation during growing season. Further analysis indicated that the temporal variation in AM fungal community only occurred in control treatment, but not in low, moderate, and high level of compost addition treatments. Our findings highlighted the significant effects of compost addition on AM growth and sporulation, and emphasized that growth stage is a stronger determinant than 1-year compost addition in shaping AM fungal community in black soil of

  4. Compost Addition Enhanced Hyphal Growth and Sporulation of Arbuscular Mycorrhizal Fungi without Affecting Their Community Composition in the Soil

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    Wei Yang

    2018-02-01

    Full Text Available Arbuscular mycorrhizal (AM fungi form symbiotic associations with most crop plant species in agricultural ecosystems, and are conspicuously influenced by various agricultural practices. To understand the impact of compost addition on AM fungi, we examined effect of four compost rates (0, 11.25, 22.5, and 45 Mg/ha on the abundance and community composition of AM fungi in seedling, flowering, and mature stage of soybean in a 1-year compost addition experiment system in Northeast China. Soybean [Glycine max (L. Merrill] was used as test plant. Moderate (22.5 Mg/ha and high (45 Mg/ha levels of compost addition significantly increased AM root colonization and extraradical hyphal (ERH density compared with control, whereas low (11.5 Mg/ha level of compost addition did not cause significant increase in AM root colonization and ERH density. AM fungal spore density was significantly enhanced by all the compost rates compared with control. The temporal variations analysis revealed that, AM root colonization in seedling stage was significantly lower than in flowering and mature stage. Although AM fungal operational taxonomic unit richness and community composition was unaffected by compost addition, some abundant AM fungal species showed significantly different response to compost addition. In mature stage, Rhizophagus fasciculatum showed increasing trend along with compost addition gradient, whereas the opposite was observed with Paraglomus sp. In addition, AM fungal community composition exhibited significant temporal variation during growing season. Further analysis indicated that the temporal variation in AM fungal community only occurred in control treatment, but not in low, moderate, and high level of compost addition treatments. Our findings highlighted the significant effects of compost addition on AM growth and sporulation, and emphasized that growth stage is a stronger determinant than 1-year compost addition in shaping AM fungal community in

  5. Functional Genomic Analysis of Candida albicans Adherence Reveals a Key Role for the Arp2/3 Complex in Cell Wall Remodelling and Biofilm Formation.

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    Lee, Jason A; Robbins, Nicole; Xie, Jinglin L; Ketela, Troy; Cowen, Leah E

    2016-11-01

    Fungal biofilms are complex, structured communities that can form on surfaces such as catheters and other indwelling medical devices. Biofilms are of particular concern with Candida albicans, one of the leading opportunistic fungal pathogens of humans. C. albicans biofilms include yeast and filamentous cells that are surrounded by an extracellular matrix, and they are intrinsically resistant to antifungal drugs such that resolving biofilm infections often requires surgery to remove the contaminated device. C. albicans biofilms form through a regulated process of adhesion to surfaces, filamentation, maturation, and ultimately dispersion. To uncover new strategies to block the initial stages of biofilm formation, we utilized a functional genomic approach to identify genes that modulate C. albicans adherence. We screened a library of 1,481 double barcoded doxycycline-repressible conditional gene expression strains covering ~25% of the C. albicans genome. We identified five genes for which transcriptional repression impaired adherence, including: ARC18, PMT1, MNN9, SPT7, and orf19.831. The most severe adherence defect was observed upon transcriptional repression of ARC18, which encodes a member of the Arp2/3 complex that is involved in regulation of the actin cytoskeleton and endocytosis. Depletion of components of the Arp2/3 complex not only impaired adherence, but also caused reduced biofilm formation, increased cell surface hydrophobicity, and increased exposure of cell wall chitin and β-glucans. Reduced function of the Arp2/3 complex led to impaired cell wall integrity and activation of Rho1-mediated cell wall stress responses, thereby causing cell wall remodelling and reduced adherence. Thus, we identify important functional relationships between cell wall stress responses and a novel mechanism that controls adherence and biofilm formation, thereby illuminating novel strategies to cripple a leading fungal pathogen of humans.

  6. Probiotic Bacteria Alter Pattern-Recognition Receptor Expression and Cytokine Profile in a Human Macrophage Model Challenged with Candida albicans and Lipopolysaccharide

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    Victor H. Matsubara

    2017-11-01

    Full Text Available Probiotics are live microorganisms that confer benefits to the host health. The infection rate of potentially pathogenic organisms such as Candida albicans, the most common agent associated with mucosal candidiasis, can be reduced by probiotics. However, the mechanisms by which the probiotics interfere with the immune system are largely unknown. We evaluated the effect of probiotic bacteria on C. albicans challenged human macrophages. Macrophages were pretreated with lactobacilli alone (Lactobacillus rhamnosus LR32, Lactobacillus casei L324m, or Lactobacillus acidophilus NCFM or associated with Escherichia coli lipopolysaccharide (LPS, followed by the challenge with C. albicans or LPS in a co-culture assay. The expression of pattern-recognition receptors genes (CLE7A, TLR2, and TLR4 was determined by RT-qPCR, and dectin-1 reduced levels were confirmed by flow cytometry. The cytokine profile was determined by ELISA using the macrophage cell supernatant. Overall probiotic lactobacilli down-regulated the transcription of CLEC7A (p < 0.05, resulting in the decreased expression of dectin-1 on probiotic pretreated macrophages. The tested Lactobacillus species down-regulated TLR4, and increased TLR2 mRNA levels in macrophages challenged with C. albicans. The cytokines profile of macrophages challenged with C. albicans or LPS were altered by the probiotics, which generally led to increased levels of IL-10 and IL-1β, and reduction of IL-12 production by macrophages (p < 0.05. Our data suggest that probiotic lactobacilli impair the recognition of PAMPs by macrophages, and alter the production of pro/anti-inflammatory cytokines, thus modulating inflammation.

  7. Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.

    Science.gov (United States)

    Martins, Carlos Henrique Gomes; Pires, Regina Helena; Cunha, Aline Oliveira; Pereira, Cristiane Aparecida Martins; Singulani, Junya de Lacorte; Abrão, Fariza; Moraes, Thais de; Mendes-Giannini, Maria José Soares

    2016-04-01

    Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p albicans Candida strains, after 6 h 37 °C. The total C. albicans CFU from a dual-species biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  8. Triclosan Enhances the Clearing of Pathogenic Intracellular Salmonella or Candida albicans but Disturbs the Intestinal Microbiota through mTOR-Independent Autophagy

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    Chao Wang

    2018-02-01

    Full Text Available Triclosan (TCS is a broad-spectrum antimicrobial agent, whose well-known antibacterial mechanism is inhibiting lipid synthesis. Autophagy, an innate immune response, is an intracellular process that delivers the cargo including pathogens to lysosomes for degradation. In this study, we first demonstrated that TCS induced autophagy in a dose-dependent manner in non-phagocytic cells (HeLa and in macrophages (Raw264.7 and in vivo. The western blot results also revealed that TCS induced autophagy via the AMPK/ULK1 and JNK/ERK/p38 pathways independent of mTOR. The immunofluorescence results indicated that TCS up-regulated the expression of the ubiquitin receptors NDP52 and p62 and strengthened the co-localization of these receptors with Salmonella enterica Typhimurium (S. typhimurium or Candida albicans (C. albicans in infected MΦ cells. In addition, sub-lethal concentrations of TCS enhanced the clearing of the pathogens S. typhimurium or C. albicans in infected MΦ and in corresponding mouse infection models in vivo. Specifically, we found that a sub-inhibitory concentration of TCS induced autophagy, leading to an imbalance of the intestinal microflora in mice through the analysis of 16s rRNA Sequencing. Together, these results demonstrated that TCS induced autophagy, which enhanced the killing against pathogenic S. typhimurium or C. albicans within mammal cells but broke the balance of the intestinal microflora.

  9. CANDIDA ALBICANS AND NON-ALBICANS SPECIES AS ETIOLOGICAL AGENT OF VAGINITIS IN PREGNANT AND NONPREGNANT WOMEN

    Science.gov (United States)

    Babić, Mirela; Hukić, Mirsada

    2010-01-01

    Pregnancy represents a risk factor in the occurrence of vaginal candidosis. The objectives of our study were: to make determination of the microscopic findings of vaginal swab, frequency of Candida species in the culture of pregnant women and patients who are not pregnant, determine the Candida species in all cultures, and to determine the frequency and differences in the frequency of C. albicans and other non-albicans species. In one year study performed during 2006 year, we tested patients of Gynaecology and Obstetrics clinic of the Clinical Centre in Sarajevo and Gynaecology department of the General hospital in Sarajevo. 447 woman included in the study were separated in two groups: 203 pregnant (in the last trimester of pregnancy), and 244 non-pregnant woman in period of fertility. Each vaginal swab was examined microscopically. The yeast, number of colonies, and the species of Candida were determined on Sabouraud dextrose agar with presence of antibiotics. For determination of Candida species, we used germ tube test for detection of C. albicans, and cultivation on the selective medium and assimilation tests for detection of non-albicans species. The results indicated positive microscopic findings in the test group (40,9%), as well as greater number of positive cultures (46,8%). The most commonly detected species for both groups was C. albicans (test group 40.9% and control group 23,0%). The most commonly detected non-albicans species for the test group were C. glabrata (4,2 %) and C. krusei (3,2%), and for the control group were C. glabrata (3,2%) and C. parapsilosis (3,2%). The microscopic findings correlated with the number of colonies in positive cultures. In the test group, we found an increased number of yeasts (64,3%), and the pseudopyphae and blastopores by microscopic examination as an indication of infection. In the control group, we found a small number of yeasts (64,6%), in the form of blastopores, as an indication of the candida colonisation. Our

  10. An immunological link between Candida albicans colonization and Crohn's disease.

    Science.gov (United States)

    Gerard, Romain; Sendid, Boualem; Colombel, Jean-Frederic; Poulain, Daniel; Jouault, Thierry

    2015-06-01

    The etiology of Crohn's disease (CD), an autoimmune, inflammatory bowel disease (IBD) which affects approximately one million people in Europe, is still unclear. Nevertheless, it is widely accepted that CD could result from an inappropriate inflammatory response to intestinal microorganisms in a genetically susceptible host. Most studies to date have concerned the involvement of bacteria in disease progression. In addition to bacteria, there appears to be a possible link between the commensal yeast Candida albicans and disease development. In this review, in an attempt to link the gut colonization process and the development of CD, we describe the different pathways that are involved in the progression of CD and in the host response to C. albicans, making the yeast a possible initiator of the inflammatory process observed in this IBD.

  11. Genetics of Candida albicans, a diploid human fungal pathogen.

    Science.gov (United States)

    Noble, Suzanne M; Johnson, Alexander D

    2007-01-01

    Candida albicans is a species of fungus that typically resides in the gastrointestinal tracts of humans and other warm-blooded animals. It is also the most common human fungal pathogen, causing a variety of skin and soft tissue infections in healthy people and more virulent invasive and disseminated diseases in patients with compromised immune systems. How this microorganism manages to persist in healthy hosts but also to cause a spectrum of disease states in the immunocompromised host are questions of significant biological interest as well as major clinical and economic importance. In this review, we describe recent developments in population genetics, the mating process, and gene disruption technology that are providing much needed experimental insights into the biology of C. albicans.

  12. Host response to Candida albicans bloodstream infection and sepsis

    Science.gov (United States)

    Duggan, Seána; Leonhardt, Ines; Hünniger, Kerstin; Kurzai, Oliver

    2015-01-01

    Candida albicans is a major cause of bloodstream infection which may present as sepsis and septic shock - major causes of morbidity and mortality world-wide. After invasion of the pathogen, innate mechanisms govern the early response. Here, we outline the models used to study these mechanisms and summarize our current understanding of innate immune responses during Candida bloodstream infection. This includes protective immunity as well as harmful responses resulting in Candida induced sepsis. Neutrophilic granulocytes are considered principal effector cells conferring protection and recognize C. albicans mainly via complement receptor 3. They possess a range of effector mechanisms, contributing to elimination of the pathogen. Neutrophil activation is closely linked to complement and modulated by activated mononuclear cells. A thorough understanding of these mechanisms will help in creating an individualized approach to patients suffering from systemic candidiasis and aid in optimizing clinical management. PMID:25785541

  13. Low virulent oral Candida albicans strains isolated from smokers.

    Science.gov (United States)

    de Azevedo Izidoro, Ana Claudia Santos; Semprebom, Andressa Marafon; Baboni, Fernanda Brasil; Rosa, Rosimeire Takaki; Machado, Maria Angela Naval; Samaranayake, Lakshman Perera; Rosa, Edvaldo Antonio Ribeiro

    2012-02-01

    It is widely accepted that tabagism is a predisposing factor to oral candidosis and cumulate data suggest that cigarette compounds may increase candidal virulence. To verify if enhanced virulence occurs in Candida albicans from chronic smokers, a cohort of 42 non-smokers and other of 58 smokers (all with excellent oral conditions and without signs of candidosis) were swabbed on tong dorsum and jugal mucosa. Results showed that oral candidal loads do not differ between smoker and non-smokers. Activities of secreted aspartyl-protease (Sap), phospholipase, chondroitinase, esterase-lipase, and haemolysin secretions were screened for thirty-two C. albicans isolates. There were detected significant increments in phospholipasic and chondroitinasic activities in isolates from non-smokers. For other virulence factors, no differences between both cohorts were achieved. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Recurrent Candida albicans Ventriculitis Treated with Intraventricular Liposomal Amphotericin B

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    Demet Toprak

    2015-01-01

    Full Text Available Central nervous system (CNS infection with Candida is rare but significant because of its high morbidity and mortality. When present, it is commonly seen among immunocompromised and hospitalized patients. Herein, we describe a case of a four-year-old boy with acute lymphoblastic leukemia (ALL who experienced recurrent Candida albicans meningitis. The patient was treated successfully with intravenous liposomal amphotericin B at first attack, but 25 days after discharge he was readmitted to hospital with symptoms of meningitis. Candida albicans was grown in CFS culture again and cranial magnetic resonance imaging (MRI showed ventriculitis. We administered liposomal amphotericin B both intravenously and intraventricularly and favorable result was achieved without any adverse effects. Intraventricular amphotericin B may be considered for the treatment of recurrent CNS Candida infections in addition to intravenous administration.

  15. The Antifungal Effect of Endocyn Against Candida albicans Biofilm

    Science.gov (United States)

    2016-05-13

    quantitatively by microbiological plate count and qualitatively by confocal microscopy using Live/Dead staining. XTT data was analyzed by two-way analysis...wells of a 24-well plate containing 2 ml of sterile RPMI media . In order to achieve mature fungal biofilm formation, the plate was placed in a...exhibits rapid antifungal efficacy in vitro. C. albicans biofilms were cultivated on polystyrene, washed, and treated with Endocyn (white bar) over a

  16. Candida albicans Secreted Aspartyl Proteinases in Virulence and Pathogenesis

    OpenAIRE

    Naglik, Julian R.; Challacombe, Stephen J.; Hube, Bernhard

    2003-01-01

    Candida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known,...

  17. Alteramide B is a microtubule antagonist of inhibiting Candida albicans.

    Science.gov (United States)

    Ding, Yanjiao; Li, Yaoyao; Li, Zhenyu; Zhang, Juanli; Lu, Chunhua; Wang, Haoxin; Shen, Yuemao; Du, Liangcheng

    2016-10-01

    Alteramide B (ATB), isolated from Lysobacter enzymogenes C3, was a new polycyclic tetramate macrolactam (PTM). ATB exhibited potent inhibitory activity against several yeasts, particularly Candida albicans SC5314, but its antifungal mechanism is unknown. The structure of ATB was established by extensive spectroscopic analyses, including high-resolution mass spectrometry, 1D- and 2D-NMR, and CD spectra. Flow cytometry, fluorescence microscope, transmission electron microscope, molecular modeling, overexpression and site-directed mutation studies were employed to delineate the anti-Candida molecular mechanism of ATB. ATB induced apoptosis in C. albicans through inducing reactive oxygen species (ROS) production by disrupting microtubules. Molecular dynamics studies revealed the binding patterns of ATB to the β-tubulin subunit. Overexpression of the wild type and site-directed mutants of the β-tubulin gene (TUBB) changed the sensitivity of C. albicans to ATB, confirming the binding of ATB to β-tubulin, and indicating that the binding sites are L215, L217, L273, L274 and R282. In vivo, ATB significantly improved the survival of the candidiasis mice and reduced fungal burden. The molecular mechanism underlying the ATB-induced apoptosis in C. albicans is through inhibiting tubulin polymerization that leads to cell cycle arrest at the G2/M phase. The identification of ATB and the study of its activity provide novel mechanistic insights into the mode of action of PTMs against the human pathogen. This study shows that ATB is a new microtubule inhibitor and a promising anti-Candida lead compound. The results also support β-tubulin as a potential target for anti-Candida drug discovery. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Candida albicans in patients with oronasal communication and obturator prostheses

    OpenAIRE

    MATTOS, Beatriz Silva Câmara; SOUSA, Andréa Alves de; MAGALHÃES, Marina Helena C. G. de; ANDRÉ, Marcia; BRITO E DIAS, Reinaldo

    2009-01-01

    Patients using obturator prostheses often present denture-induced stomatitis. In order to detect the presence of oral Candida albicans in patients with oronasal communications and to evaluate the effectiveness of a topical antifungal treatment, cytological smears obtained from the buccal and palatal mucosa of 10 adult patients, and from the nasal acrylic surface of their obturator prostheses were examined. A therapeutic protocol comprising the use of oral nystatin (Mycostatin®) and prosthesis...

  19. Competitive Fitness of Fluconazole-Resistant Clinical Candida albicans Strains.

    Science.gov (United States)

    Popp, Christina; Hampe, Irene A I; Hertlein, Tobias; Ohlsen, Knut; Rogers, P David; Morschhäuser, Joachim

    2017-07-01

    The pathogenic yeast Candida albicans can develop resistance to the widely used antifungal agent fluconazole, which inhibits ergosterol biosynthesis. Resistance is often caused by gain-of-function mutations in the transcription factors Mrr1 and Tac1, which result in constitutive overexpression of multidrug efflux pumps, and Upc2, which result in constitutive overexpression of ergosterol biosynthesis genes. However, the deregulated gene expression that is caused by hyperactive forms of these transcription factors also reduces the fitness of the cells in the absence of the drug. To investigate whether fluconazole-resistant clinical C. albicans isolates have overcome the fitness costs of drug resistance, we assessed the relative fitness of C. albicans isolates containing resistance mutations in these transcription factors in competition with matched drug-susceptible isolates from the same patients. Most of the fluconazole-resistant isolates were outcompeted by the corresponding drug-susceptible isolates when grown in rich medium without fluconazole. On the other hand, some resistant isolates with gain-of-function mutations in MRR1 did not exhibit reduced fitness under these conditions. In a mouse model of disseminated candidiasis, three out of four tested fluconazole-resistant clinical isolates did not exhibit a significant fitness defect. However, all four fluconazole-resistant isolates were outcompeted by the matched susceptible isolates in a mouse model of gastrointestinal colonization, demonstrating that the effects of drug resistance on in vivo fitness depend on the host niche. Collectively, our results indicate that the fitness costs of drug resistance in C. albicans are not easily remediated, especially when proper control of gene expression is required for successful adaptation to life within a mammalian host. Copyright © 2017 American Society for Microbiology.

  20. ANTAGONISTIC EFFECT OF EDIBLE MUSHROOM EXTRACT ON CANDIDA ALBICANS GROWTH

    Directory of Open Access Journals (Sweden)

    Paccola Edneia A. de Souza

    2001-01-01

    Full Text Available Five species of edible mushrooms, Lentinula edodes, Pleurotus ostreatus, Pholiota nameko, Macrolepiota bonaerensis and Agaricus blazei, were tested for their potential to inhibit the in vitro growth of the pathogenic yeast Candida albicans. Only L. edodes had a fungistatic effect on this human pathogen. The inhibitory compound was produced intra and extracellularly in submersed L. edodes culture, and was also present in fresh and dehydrated mushroom basidiocarps. The fungistatic compound was heat sensitive and lost activity after 72 hours.

  1. Interactions of Candida albicans with host epithelial surfaces

    Directory of Open Access Journals (Sweden)

    David W. Williams

    2013-10-01

    Full Text Available Candida albicans is an opportunistic, fungal pathogen of humans that frequently causes superficial infections of oral and vaginal mucosal surfaces of debilitated and susceptible individuals. The organism is however, commonly encountered as a commensal in healthy individuals where it is a component of the normal microflora. The key determinant in the type of relationship that Candida has with its host is how it interacts with the epithelial surface it colonises. A delicate balance clearly exists between the potentially damaging effects of Candida virulence factors and the nature of the immune response elicited by the host. Frequently, it is changes in host factors that lead to Candida seemingly changing from a commensal to pathogenic existence. However, given the often reported heterogeneity in morphological and biochemical factors that exist between Candida species and indeed strains of C. albicans, it may also be the fact that colonising strains differ in the way they exploit resources to allow persistence at mucosal surfaces and as a consequence this too may affect the way Candida interacts with epithelial cells. The aim of this review is to provide an overview of some of the possible interactions that may occur between C. albicans and host epithelial surfaces that may in turn dictate whether Candida removal, its commensal persistence or infection follows.

  2. Studies on effect of Microbial Iron Chelators on Candida Albican

    International Nuclear Information System (INIS)

    Rehmani, Fouzia S.; Milicent, S.; Zaheer-Uddin

    2005-01-01

    Iron is an essential for the life of all microbe cells. It generally exists in the oxidized form Fe(III). Even under anaerobic reducing condition the metal appear to be taken up as Fe(III). Thus free-living microorganisms require specific and effective ferric ion transport system to cope with low availability of the metal. In iron deficient environment they produce a low molecular weight specific chelators called siderphores or microbial iron chelators. Siderphores compete for limited supplied of iron. These compounds came out of the cell but can not re-enter without iron due to high affinity of these siderphores often have more than one catechol/hydroxamate functions and are multidentate (usually hexadentate ligands). The aim of the present research is to check the effect of iron chelators, namely gallic acid and salisyl hydroxamate on the growth of Candida albican in vitro. C. albican is the opportunistic paltogen present as the normal flora inside human body. In vivo the growth of C. albican is distributed by the use of antibiotics and immuno suppressers. In cases of iron over-dosage in human being, the patients are treated with certain a-iron chelators. Hence an attempt is made to notice the effect that might be inhibition or enhancement of the organism in vitro. (author)

  3. Distribution of Candida albicans genotypes among family members

    Science.gov (United States)

    Mehta, S. K.; Stevens, D. A.; Mishra, S. K.; Feroze, F.; Pierson, D. L.

    1999-01-01

    Thirty-three families (71 subjects) were screened for the presence of Candida albicans in mouthwash or stool specimens; 12 families (28 subjects) were culture-positive for this yeast. An enrichment procedure provided a twofold increase in the recovery of C. albicans from mouthwash specimens. Nine of the twelve culture-positive families had two positive members each, two families had three positive members each, and one family had four positive members. Genetic profiles were obtained by three methods: pulsed-field gel electrophoresis; restriction endonuclease analysis, and random amplification of polymorphic DNA analysis. DNA fingerprinting of C. albicans isolated from one body site three consecutive times revealed that each of the 12 families carried a distinct genotype. No two families shared the same strain, and two or more members of a family commonly shared the same strain. Intrafamily genotypic identity (i.e., each member within the family harbored the same strain) was demonstrated in six families. Genotypes of isolates from husband and wife differed from one another in five families. All three methods were satisfactory in determining genotypes; however, we concluded that restriction endonuclease analysis provided adequate resolving power.

  4. Inhibition of human natural killer (NK) cytotoxicity by Candida albicans

    International Nuclear Information System (INIS)

    Zunino, S.; Hudig, D.

    1986-01-01

    Experiments were initiated to determine whether human NK cells are cytotoxic to C. albicans with similar activity observed for mouse NK cells against the yeast Paracoccidiodes brasiliensis. In 48 hour assays using limiting dilutions of C. albicans, strain 3153A, mononuclear leukocytes with NK activity had only marginal effects on yeast outgrowth, whereas granulocytes killed most of the yeast. However, these yeast were able to block NK activity in 4 hr 51 Cr release assays with K562 cells, at yeast to K562 ratios of 10:1 and 100:1. Yeast pretreated with the serum of the majority of donors blocked the NK activity more than untreated yeast. Two of the 7 donors did not enhance NK inhibition after pretreatment of the yeast with their serum. Serum antibody to C. albicans and complement consumption by the yeast correlated with the relative efficiency of NK inhibition for most donors. This report suggests that there may be in vivo interactions between NK cells of the immune system and opportunistic fungal pathogens, which may compromise NK cell function

  5. A Human-Curated Annotation of the Candida albicans Genome.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available Recent sequencing and assembly of the genome for the fungal pathogen Candida albicans used simple automated procedures for the identification of putative genes. We have reviewed the entire assembly, both by hand and with additional bioinformatic resources, to accurately map and describe 6,354 genes and to identify 246 genes whose original database entries contained sequencing errors (or possibly mutations that affect their reading frame. Comparison with other fungal genomes permitted the identification of numerous fungus-specific genes that might be targeted for antifungal therapy. We also observed that, compared to other fungi, the protein-coding sequences in the C. albicans genome are especially rich in short sequence repeats. Finally, our improved annotation permitted a detailed analysis of several multigene families, and comparative genomic studies showed that C. albicans has a far greater catabolic range, encoding respiratory Complex 1, several novel oxidoreductases and ketone body degrading enzymes, malonyl-CoA and enoyl-CoA carriers, several novel amino acid degrading enzymes, a variety of secreted catabolic lipases and proteases, and numerous transporters to assimilate the resulting nutrients. The results of these efforts will ensure that the Candida research community has uniform and comprehensive genomic information for medical research as well as for future diagnostic and therapeutic applications.

  6. [Study on andrographolide-induced apoptosis of Candida albicans biofilm dispersion cells].

    Science.gov (United States)

    Wang, Changzhong; Han, Ning; Xu, Zhenhua; Cheng, Huijuan; Guan, Yan; Yun, Yun; Wang, Yan

    2012-02-01

    To detect the effect of andrographolide on apoptosis of Candida albicans biofilm dispersion cells. The morphological changes of apoptotic C. albicans biofilm cells were observed by using Hoechst 33258 staining Fluorescence microscope; changes of mitochondrial membrane potential (MMP) of C. albicans biofilm cells were detected by rhodamine 123 staining flow cytometry; and reactive oxygen species (ROS) was detected by DHR staining flow cytometry. 1 000, 100 micromol x L(-1) of andrographolide could cause pyknosis and dense staining of C. albicans biofilm cells, 1 000, 100, 10 micromol x L(-1) of andrographolide could decrease MMP and increase ROS of C. albicans biofilm cells. Andrographolide of appropriate concentrations could induce apoptosis of dispersion cells of C. albicans biofilms.

  7. Antifungal activity of extracts and isolated compounds from Buchenavia tomentosa on Candida albicans and non-albicans.

    Science.gov (United States)

    Teodoro, Guilherme R; Brighenti, Fernanda L; Delbem, Alberto C Botazzo; Delbem, Ádina Cléia B; Khouri, Sonia; Gontijo, Aline Vidal L; Pascoal, Aislan Crf; Salvador, Marcos J; Koga-Ito, Cristiane Y

    2015-01-01

    This study aimed to evaluate the antifungal activity of Buchenavia tomentosa extract and bioactive compounds on six Candida species. The antimicrobial activity of extract was evaluated using standard strains and clinical isolates. Cytotoxicity was tested in order to evaluate cell damage caused by the extract. Extract was chemically characterized and the antifungal activity of its compounds was evaluated. Extract showed antifungal activity on Candida species. Candida non-albicans were more susceptible than Candida albicans. Low cytotoxicity for extract was observed. The isolated compounds presented antifungal activity at least against one Candida spp. and all compounds presented antifungal effect on Candida glabrata. Extracts from Buchenavia tomentosa showed promising antifungal activity on Candida species with low cytotoxicity. Gallic acid, corilagin and ellagic acid showed promising inhibitory activity on Candida glabrata.

  8. Essential Functional Modules for Pathogenic and Defensive Mechanisms in Candida albicans Infections

    OpenAIRE

    Wang, Yu-Chao; Tsai, I-Chun; Lin, Che; Hsieh, Wen-Ping; Lan, Chung-Yu; Chuang, Yung-Jen; Chen, Bor-Sen

    2014-01-01

    The clinical and biological significance of the study of fungal pathogen Candida albicans (C. albicans) has markedly increased. However, the explicit pathogenic and invasive mechanisms of such host-pathogen interactions have not yet been fully elucidated. Therefore, the essential functional modules involved in C. albicans-zebrafish interactions were investigated in this study. Adopting a systems biology approach, the early-stage and late-stage protein-protein interaction (PPI) networks for bo...

  9. Sputum Candida albicans presages FEV₁ decline and hospital-treated exacerbations in cystic fibrosis.

    LENUS (Irish Health Repository)

    Chotirmall, Sanjay H

    2010-11-01

    The role of Candida albicans in the cystic fibrosis (CF) airway is underexplored. Considered a colonizer, few question its pathogenic potential despite high isolation frequencies from sputum culture. We evaluated the frequency and identified the strongest predictors of C albicans colonization in CF. Independent associations of colonization with clinical outcomes were determined, and the longitudinal effects of C albicans acquisition on BMI and FEV₁ were evaluated.

  10. Effect of Xylitol on Candida albicans resistance in serum (in vitro study

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    Ria Puspitawati

    2013-07-01

    Full Text Available Xylitol is reported to inhibit the growth of C. albicans. Objectives: Investigating serum factor role in inhibiting the growth of C. albicans and the effect of 1%, 5%, 10% xylitol on C. albicans resistance in serum in vitro. Methods: Identification of C. albicans (oral swab of candidiasis patient was conducted using CHROMAgar, confirmed by germ tube test. The cultures were serially diluted, inoculated in Saburoud Dextrose Broth (SDB contained 0% (control, 1%, 5%, or 10% xylitol, and kept for 3 or 7 days. These inoculations were then exposed to either active or inactive serum (Fetal Bovine Serum heated in 65ºC for 30 minutes for 2 hours in 37ºC. The colony forming unit (CFU of C. albicans in Saburoud Dextrose Agar (SDA were counted after 2 days. C. albicans ATCC 10231 strain was used as a comparison. One-way ANOVA with 0.05 was used. Results: After 3 days cultured in media with or without xylitol, the CFU of C. albicans exposed to active serum were significantly lower than those exposed to inactive serum (p=0.032. Although not statistically significant (p=0.689, increased concentration of xylitol lead to increased resistance of C. albicans in active serum. Only 7 day exposure of 10% xylitol resulted in significantly higher growth of C. albicans (p=0.034. No significant difference of C. albicans CFU in active or inactive serum (p=0.404. Conclusion: Serum factor has role in inhibiting C. albicans growth in vitro. Exposure of 1%, 5%, or 10% xylitol for 3 or 7 days has no significant effect on C. albicans resistance in serum.DOI: 10.14693/jdi.v16i2.98

  11. Inhibitory Effect of Alpha-Mangostin on Adhesion of Candida albicans to Denture Acrylic

    OpenAIRE

    Kaomongkolgit, Ruchadaporn; Jamdee, Kusuma

    2015-01-01

    Objective: Candida-associated denture stomatitis is a very common disease affecting denture wearers. It is characterized by the presence of yeast biofilm on the denture, primarily associated with C. albicans. The investigation of agents that can reduce C. albicans adhesion may represent a significant advancement in the prevention and treatment of this disease. This study aims to investigate the effect of alpha-mangostin on the in vitro adhesion of C. albicans to denture acrylic and germ tube ...

  12. Miltefosine inhibits Candida albicans and non-albicans Candida spp. biofilms and impairs the dispersion of infectious cells.

    Science.gov (United States)

    Vila, Taissa; Ishida, Kelly; Seabra, Sergio Henrique; Rozental, Sonia

    2016-11-01

    Candida spp. can adhere to and form biofilms over different surfaces, becoming less susceptible to antifungal treatment. Resistance of biofilms to antifungal agents is multifactorial and the extracellular matrix (ECM) appears to play an important role. Among the few available antifungals for treatment of candidaemia, only the lipid formulations of amphotericin B (AmB) and the echinocandins are effective against biofilms. Our group has previously demonstrated that miltefosine has an important effect against Candida albicans biofilms. Thus, the aim of this work was to expand the analyses of the in vitro antibiofilm activity of miltefosine to non-albicans Candida spp. Miltefosine had significant antifungal activity against planktonic cells and the development of biofilms of C. albicans, Candida parapsilosis, Candida tropicalis and Candida glabrata. The activity profile in biofilms was superior to fluconazole and was similar to that of AmB and caspofungin. Biofilm-derived cells with their ECM extracted became as susceptible to miltefosine as planktonic cells, confirming the importance of the ECM in the biofilm resistant behaviour. Miltefosine also inhibited biofilm dispersion of cells at the same concentration needed to inhibit planktonic cell growth. The data obtained in this work reinforce the potent inhibitory activity of miltefosine on biofilms of the four most pathogenic Candida spp. and encourage further studies for the utilisation of this drug and/or structural analogues on biofilm-related infections. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  13. Cranberry proanthocyanidins inhibit the adherence properties of Candida albicans and cytokine secretion by oral epithelial cells

    Science.gov (United States)

    2012-01-01

    Background Oral candidiasis is a common fungal disease mainly caused by Candida albicans. The aim of this study was to investigate the effects of A-type cranberry proanthocyanidins (AC-PACs) on pathogenic properties of C. albicans as well as on the inflammatory response of oral epithelial cells induced by this oral pathogen. Methods Microplate dilution assays were performed to determine the effect of AC-PACs on C. albicans growth as well as biofilm formation stained with crystal violet. Adhesion of FITC-labeled C. albicans to oral epithelial cells and to acrylic resin disks was monitored by fluorometry. The effects of AC-PACs on C. albicans-induced cytokine secretion, nuclear factor-kappa B (NF-κB) p65 activation and kinase phosphorylation in oral epithelial cells were determined by immunological assays. Results Although AC-PACs did not affect growth of C. albicans, it prevented biofilm formation and reduced adherence of C. albicans to oral epithelial cells and saliva-coated acrylic resin discs. In addition, AC-PACs significantly decreased the secretion of IL-8 and IL-6 by oral epithelial cells stimulated with C. albicans. This anti-inflammatory effect was associated with reduced activation of NF-κB p65 and phosphorylation of specific signal intracellular kinases. Conclusion AC-PACs by affecting the adherence properties of C. albicans and attenuating the inflammatory response induced by this pathogen represent potential novel therapeutic agents for the prevention/treatment of oral candidiasis. PMID:22248145

  14. The role of pattern recognition receptors in the innate recognition of Candida albicans

    Science.gov (United States)

    Zheng, Nan-Xin; Wang, Yan; Hu, Dan-Dan; Yan, Lan; Jiang, Yuan-Ying

    2015-01-01

    Candida albicans is both a commensal microorganism in healthy individuals and a major fungal pathogen causing high mortality in immunocompromised patients. Yeast-hypha morphological transition is a well known virulence trait of C. albicans. Host innate immunity to C. albicans critically requires pattern recognition receptors (PRRs). In this review, we summarize the PRRs involved in the recognition of C. albicans in epithelial cells, endothelial cells, and phagocytic cells separately. We figure out the differential recognition of yeasts and hyphae, the findings on PRR-deficient mice, and the discoveries on human PRR-related single nucleotide polymorphisms (SNPs). PMID:25714264

  15. Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

    Science.gov (United States)

    Jacques Rezende Delgado, Ronan; Helena Gasparoto, Thaís; Renata Sipert, Carla; Ramos Pinheiro, Claudia; Gomes de Moraes, Ivaldo; Brandão Garcia, Roberto; Antônio Hungaro Duarte, Marco; Monteiro Bramante, Clóvis; Aparecido Torres, Sérgio; Pompermaier Garlet, Gustavo; Paula Campanelli, Ana; Bernardineli, Norberti

    2013-01-01

    This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans. PMID:23538639

  16. Factors Influencing Non-albicans Candidemia: A Case-Case-Control Study.

    Science.gov (United States)

    Kofteridis, Diamantis P; Valachis, Antonis; Dimopoulou, Dimitra; Andrianaki, Angeliki M; Christidou, Athanasia; Maraki, Sofia; Spernovasilis, Nikolaos A; Samonis, George

    2017-08-01

    The study identified factors predisposing to non-albicans candidemia with special interest to prior antimicrobial treatment. A retrospective, case-case-control study was performed at the University Hospital of Heraklion, Greece, from November 2007 through September 2011 including adult patients. The study had three groups. The first included 58 patients with non-albicans candidemia, the second 48 with C. albicans candidemia, while the third (control) 104 without candidemia. Each of the two candidemia groups was compared with the control using multivariate logistic regression model. The mean (SD) age of the non-albicans, the albicans and the control patients was 67 (12), 67 (18) and 59 (19) years, respectively. The most common non-albicans Candida spp. isolated were C. parapsilosis in 19 patients (33%), C. glabrata in 17 (29%) and C. tropicalis in 15 (26%). Independent risk factors for non-albicans candidemia were prior treatment with quinolones (p candidemia were prior treatment with quinolones (p candidemia groups. The study reveals the role of antimicrobial exposure as a risk factor for candidemia caused by different species. Prior treatment with b-lactam-b-lactamase inhibitors was associated with non-albicans, while with carbapenems with C. albicans candidemia. Prior use of quinolones was associated with candidemia in general.

  17. Arachidonic acid affects biofilm formation and PGE2 level in Candida albicans and non-albicans species in presence of subinhibitory concentration of fluconazole and terbinafine.

    Science.gov (United States)

    Mishra, Nripendra Nath; Ali, Shakir; Shukla, Praveen K

    2014-01-01

    Candida albicans utilizes arachidonic acid (AA) released during the course of infection (Candidiasis) from phospholipids of infected host cell membranes and synthesizes extracellular prostaglandin(s) which play an important role in hyphae formation and host cell damage. C. albicans biofilms secrete significantly more prostaglandin(s) and evidence suggests that Candida biofilms have dramatically reduced susceptibility to majority of antifungal drugs. AA influences the saturation level of lipids and fluidity of yeast cell membranes. Therefore the aim of this study was to evaluate the effect of AA alone or in combination with antifungal agents on biofilm formation and production of prostaglandin (PGE2) in C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, and C. albicans amphotericin B resistant strain (AmBR). Maximum biofilm formation was found to be in the case of C. albicans compared to C. non-albicans species. However, among the non-albicans species C. tropicalis exhibited highest biofilm formation. Treatment with AA in combination with subinhibitory concentrations of fluconazole and terbinafine separately exhibited significant (p<0.05) reduction in biofilm formation against C. glabrata, C. parapsilosis, C. tropicalis and AmBR as compared to their individual effect. Further, these two antifungal agents in combination with AA caused an increase in production of prostaglandin from fungal cell itself which was significant (p<0.05) in case of all the strains tested. Copyright © 2013 Elsevier Editora Ltda. All rights reserved.

  18. Enrichment and Broad Representation of Plant Biomass-Degrading Enzymes in the Specialized Hyphal Swellings of Leucoagaricus gongylophorus, the Fungal Symbiont of Leaf-Cutter Ants

    Energy Technology Data Exchange (ETDEWEB)

    Aylward, Frank O.; Khadempour, Lily; Tremmel, Daniel; McDonald, Bradon R.; Nicora, Carrie D.; Wu, Si; Moore, Ronald J.; Orton, Daniel J.; Monroe, Matthew E.; Piehowski, Paul D.; Purvine, Samuel O.; Smith, Richard D.; Lipton, Mary S.; Burnum-Johnson, Kristin E.; Currie, Cameron R.

    2015-08-28

    Leaf-cutter ants are prolific and conspicuous Neotropical herbivores that derive energy from specialized fungus gardens they cultivate using foliar biomass. The basidiomycetous cultivar of the ants, Leucoagaricus gongylophorus, produces specialized hyphal swellings called gongylidia that serve as the primary food source of ant colonies. Gongylidia also contain lignocellulases that become concentrated in ant digestive tracts and are deposited within fecal droplets onto fresh foliar material as it is foraged by the ants. Although the enzymes concentrated by L. gongylophorus within gongylidia are thought to be critical to the initial degradation of plant biomass, only a few enzymes present in these hyphal swellings have been identified. Here we use proteomic methods to identify proteins present in the gongylidia of three Atta cephalotes colonies. Our results demonstrate that a diverse but consistent set of enzymes is present in gongylidia, including numerous lignocellulases likely involved in the degradation of polysaccharides, plant toxins, and proteins. Overall, gongylidia contained over three-quarters of all lignocellulases identified in the L. gongylophorus genome, demonstrating that the majority of the enzymes produced by this fungus for biomass breakdown are ingested by the ants. We also identify a set of 23 lignocellulases enriched in gongylidia compared to whole fungus garden samples, suggesting that certain enzymes may be particularly important in the initial degradation of foliar material. Our work sheds light on the complex interplay between leaf-cutter ants and their fungal symbiont that allows for the host insects to occupy an herbivorous niche by indirectly deriving energy from plant biomass.

  19. The Mnn2 mannosyltransferase family modulates mannoprotein fibril length, immune recognition and virulence of Candida albicans.

    Directory of Open Access Journals (Sweden)

    Rebecca A Hall

    Full Text Available The fungal cell wall is the first point of interaction between an invading fungal pathogen and the host immune system. The outer layer of the cell wall is comprised of GPI anchored proteins, which are post-translationally modified by both N- and O-linked glycans. These glycans are important pathogen associated molecular patterns (PAMPs recognised by the innate immune system. Glycan synthesis is mediated by a series of glycosyl transferases, located in the endoplasmic reticulum and Golgi apparatus. Mnn2 is responsible for the addition of the initial α1,2-mannose residue onto the α1,6-mannose backbone, forming the N-mannan outer chain branches. In Candida albicans, the MNN2 gene family is comprised of six members (MNN2, MNN21, MNN22, MNN23, MNN24 and MNN26. Using a series of single, double, triple, quintuple and sextuple mutants, we show, for the first time, that addition of α1,2-mannose is required for stabilisation of the α1,6-mannose backbone and hence regulates mannan fibril length. Sequential deletion of members of the MNN2 gene family resulted in the synthesis of lower molecular weight, less complex and more uniform N-glycans, with the sextuple mutant displaying only un-substituted α1,6-mannose. TEM images confirmed that the sextuple mutant was completely devoid of the outer mannan fibril layer, while deletion of two MNN2 orthologues resulted in short mannan fibrils. These changes in cell wall architecture correlated with decreased proinflammatory cytokine induction from monocytes and a decrease in fungal virulence in two animal models. Therefore, α1,2-mannose of N-mannan is important for both immune recognition and virulence of C. albicans.

  20. Adherence of yeast and filamentous forms of Candida albicans to cultured enterocytes.

    Science.gov (United States)

    Wiesner, Stephen M; Bendel, Catherine M; Hess, Donavon J; Erlandsen, Stanley L; Wells, Carol L

    2002-03-01

    Systemic candidiasis is a major cause of complicating infections in intensive care units. Morbidity and mortality are high, even in those who receive appropriate antifungal therapy. Because the intestinal tract is considered a major portal of entry for systemic candidiasis, experiments were designed to clarify the ability of yeast and filamentous forms, as well as the INT1 gene product, to influence adherence of Candida albicans to the intestinal epithelium. Controlled. University teaching hospital research laboratory. Mature Caco-2 and HT-29 cultured enterocytes. C. albicans INT1 mutant strains, defective in filament production, were used to observe the ultrastructural surface interactions of C. albicans with cultured intestinal epithelial cells, namely Caco-2 and HT-29 cells. These mutant strains also were used to quantify the effect of the INT1 gene product on C. albicans adherence (yeast and filamentous forms) to cultured enterocytes. Ultrastructural surface interactions of C. albicans with cultured enterocytes were observed with high resolution scanning electron microscopy. C. albicans adherence to cultured enterocytes was quantified by using a colorimetric enzyme-linked immunosorbent assay. Both yeast and filamentous forms of C. albicans appeared tightly adherent to the apical surface of cultured enterocytes, and INT1 appeared to have little, if any, effect on these ultrastructural surface interactions. The distal ends of C. albicans filaments appeared to mediate adherence to enterocyte apical microvilli, and thigmotropism (contact guidance) appeared to play a role in C. albicans adherence. The absence of functional INT1 was associated with decreased adherence of C. albicans yeast forms to cultured enterocytes. Although functional INT1 appeared to facilitate adherence of C. albicans yeast forms to cultured enterocytes, the role of INT1 in adherence of filamentous forms was unclear, and both yeast and filamentous forms could adhere to, and perhaps invade, the

  1. Cancer drugs inhibit morphogenesis in the human fungal pathogen, Candida albicans

    Directory of Open Access Journals (Sweden)

    Madhushree M Routh

    2013-09-01

    Full Text Available Candida infections are very common in cancer patients and it is a common practice to prescribe antifungal antibiotics along with anticancer drugs. Yeast to hyphal form switching is considered to be important in invasive candidiasis. Targeting morphogenetic switching may be useful against invasive candidiasis. In this study, we report the antimorphogenetic properties of thirty cancer drugs.

  2. Candida albicans biofilm development in vitro for photodynamic therapy study

    International Nuclear Information System (INIS)

    Suzuki, Luis Claudio

    2009-01-01

    Photodynamic therapy (PDT) is a phototherapy based on the use of a photo sensitizer (PS) in the presence of low intensity light with resonant wavelength of absorption of the PS and biological systems that can raise awareness, generating reactive oxygen species. Studies show that PDT has a lethal effect on Candida albicans. The biofilm formed by C. albicans is the cause of infections associated with medical devices such as catheters, with a proven resistance to antifungal agents, and the removal of the catheter colonized almost always is necessary. However, few studies in literature report the behavior and response of biofilm organized by C. albicans against PDT. The aims of this study were to develop a methodology for in vitro biofilm formation of C. albicans, evaluate the sensitivity of the biofilm of C. albicans to antimicrobial photodynamic therapy using PS as the methylene blue (MB) and hypocrellin B: La +3 (HBL a+3 ) and analyze the biofilm by Optical Coherence Tomography (OCT). For biofilm formation, discs were made from elastomeric silicone catheters. The PS were dissolved in solution of PBS, and the MB had two different concentrations tested in the biofilm: 100μM and 1mM; HBLa +3 only one of 10μM. The irradiation of both dyes with the microorganism was done by two different LEDs, one with red emission at λ = 630nm ± 20nm and the other one blue emission at λ = 460nm ± 30nm. We performed a curve of survival fraction versus time of irradiation of each sample with biofilm and suspension of the microorganism in the yeast form to verify the susceptibility of the front PDT. The yeast showed 100% reduction using both PS, but at different times of irradiation (30s to HBLa +3 and 6 min for the MB at 100μM). When the therapy was applied in biofilm, the MB 100μM did not show any significant reduction, while at concentration of 1mM was reduced by 100% after 6 min of irradiation. The HBLa +3 biofilm group showed a lower reduction in the concentration of 10μM in

  3. Candida albicans biofilm on titanium: effect of peroxidase precoating

    Directory of Open Access Journals (Sweden)

    Mohamed Ahariz

    2010-08-01

    Full Text Available Mohamed Ahariz1, Philippe Courtois1,21Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Brussels, 2UER de Biologie Médicale, Haute Ecole Francisco Ferrer, Brussels, BelgiumAbstract: The present study aimed to document Candida albicans biofilm development on titanium and its modulation by a peroxidase-precoated material which can generate antimicrobials, such as hypoiodite or hypothiocyanite, from hydrogen peroxide, iodide, or thiocyanate. For this purpose, titanium (powder or foil was suspended in Sabouraud liquid medium inoculated with C. albicans ATCC10231. After continuous stirring for 2–21 days at room temperature, the supernatant was monitored by turbidimetry at 600 nm and titanium washed three times in sterile Sabouraud broth. Using the tetrazolium salt MTT-formazan assay, the titanium-adherent fungal biomass was measured as 7.50 ± 0.60 × 106 blastoconidia per gram of titanium powder (n = 30 and 0.50 ± 0.04 × 106 blastoconidia per cm² of titanium foil (n = 12. The presence of yeast on the surface of titanium was confirmed by microscopy both on fresh preparations and after calcofluor white staining. However, in the presence of peroxidase systems (lactoperoxidase with substrates such as hydrogen peroxide donor, iodide, or thiocyanate, Candida growth in both planktonic and attached phases appeared to be inhibited. Moreover, this study demonstrates the possible partition of peroxidase systems between titanium material (peroxidase-precoated and liquid environment (containing peroxidase substrates to limit C. albicans biofilm formation.Keywords: adhesion, material, oral, yeast

  4. Property differences among the four major Candida albicans strain clades.

    Science.gov (United States)

    MacCallum, Donna M; Castillo, Luis; Nather, Kerstin; Munro, Carol A; Brown, Alistair J P; Gow, Neil A R; Odds, Frank C

    2009-03-01

    A selection of 43 Candida albicans isolates, chosen to represent the four major strain clades of the species and also intraclade diversity, was screened for their virulence in the murine intravenous challenge model of C. albicans infection, for a range of properties measurable in vitro that might relate to virulence, and for the numbers of midrepeat sequences in genes of the ALS and HYR families. Heterozygosity at the mating type locus and low whole-cell acid phosphatase activity and growth rate at 40 degrees C were found to be significantly positively associated with the most virulent isolates. Acid phosphatase activity and growth in 2 M NaCl were statistically significant variables between clades by univariate analysis. Isolates in different clades also differed significantly in midrepeat sequence alleles of ALS2, ALS4, ALS6, ALS7, ALS9, HYR1, and HYR2. There was no association between the midrepeat alleles of any ALS or HYR gene and the virulence of isolates to mice. Genome-wide transcript profiles of 20 isolates (5 per clade) grown under two conditions showed considerable variation between individual isolates, but only a small number of genes showed statistically significant differential gene expression between clades. Analysis of the expression profiles by overall strain virulence revealed 18 open reading frames differing significantly between isolates of high, intermediate, and low virulence. Four of these genes encoded functions related to phosphate uptake and metabolism. This finding and the significant association between whole-cell acid phosphatase activity and virulence led us to disrupt PHO100, which encodes a predicted periplasmic acid phosphatase. The pho100Delta mutant was mildly but significantly attenuated in terms of survival curves in the mouse model. The study has extended the range of properties known to differ between C. albicans clades and suggests a possible but minor role of phosphate metabolism in the virulence of the species.

  5. Optimization and Validation of Multilocus Sequence Typing for Candida albicans

    Science.gov (United States)

    Tavanti, Arianna; Gow, Neil A. R.; Senesi, Sonia; Maiden, Martin C. J.; Odds, Frank C.

    2003-01-01

    Multilocus sequence typing (MLST) was applied to 75 Candida albicans isolates, including 2 that were expected to be identical, 48 that came from diverse geographical and clinical sources, and 15 that were sequential isolates from two patients. DNA fragments (≈500 bp) of eight genes encoding housekeeping functions were sequenced, including four that have been described before for C. albicans MLST, and four new gene fragments, AAT1a, AAT1b, MPI, and ZWF1. In total, 87 polymorphic sites were found among 50 notionally different isolates, giving 46 unique sequence types, underlining the power of MLST to differentiate isolates for epidemiological studies. Additional typing information was obtained by detecting variations in size at the transcribed spacer region of the 25S rRNA gene and tests for homozygosity at the mating type-like (MTL) locus. The stability of MLST was confirmed in two sets of consecutive isolates from two patients. In each set the isolates were identical or varied by a single nucleotide. Reference strain SC5314 and a derived mutant, CAF2, gave identical MLST types. Heterozygous polymorphisms were found in at least one isolate for all but 16 (18.4%) of the variable nucleotides, and 35 (41%) of the 87 individual sequence changes generated nonsynonymous amino acids. Cloning and restriction digestion of a gene fragment containing heterozygous polymorphisms indicated that the heterozygosity was genuine and not the result of sequencing errors. Our data validate and extend previous MLST results for C. albicans, and we propose an optimized system based on sequencing eight gene fragments for routine MLST with this species. PMID:12904388

  6. Selection of aptamers for Candida albicans by cell-SELEX

    International Nuclear Information System (INIS)

    Miranda, Alessandra Nunes Duarte

    2017-01-01

    The growing concern with invasive fungal infections, responsible for an alarming mortality rate of immunosuppressed patients and in Intensive Care Units, evidences the need for a fast and specific method for the Candida albicans detection, since this species is identified as one of the main causes of septicemia. Commonly, it is a challenge for clinicians to determine the primary infection foci, the dissemination degree, or whether the site of a particular surgery is involved. Although scintigraphic imaging represents a promising tool for infectious foci detection, it still lacks a methodology for C. albicans diagnosis due to the absence of specific radiotracers for this microorganism. Aptamers are molecules that have almost ideal properties for use as diagnostic radiopharmaceuticals, such as high specificity for their molecular targets, lack of immunogenicity and toxicity, high tissue penetration and rapid blood clearance. Aptamers can also be labeled with different radionuclides. This work aims to obtain aptamers for specific binding to C. albicans cells for future application as a radiopharmaceutical. It was used a variation of the SELEX (Systematic Evolution of Ligands by EXponential Enrichment) technique, termed cell-SELEX, in which cells are the targets for selection. A selection protocol was standardized using a random library of single-stranded oligonucleotides, each containing two fixed regions flanking a sequence of 40 random nucleotides. This library was incubated with C. albicans cells in the presence of competitors. Then, the binding sequences were separated by centrifugation, resuspended and amplified by PCR. The amplification was confirmed by agarose gel electrophoresis. After that, the ligands were purified to obtain a new pool of ssDNA, from which a new incubation was carried out. The selection parameters were gradually modified in order to increase stringency. This cycle was repeated 12 times to allow the selection of sequences with the maximum

  7. Genoma de Candida albicans y resistencia a las drogas

    Directory of Open Access Journals (Sweden)

    Sandra Cruz Quintana

    2017-01-01

    Full Text Available Candida albicans es un importante patógeno fúngico en los humanos tanto por su importan - cia clínica como por su uso como un modelo experimental para la investigación científica. La comprensión de la biología de este patógeno es un requisito importante para la identificación de nuevas dianas de medicamentos para la terapia antifúngica. En esta revisión nos proponemos profundizar en las características del genoma de Candida albicans, su relación con la virulen - cia y cómo influye en la resistencia a las drogas antifùngicas, que nos permita comprender los mecanismos por los cuales ejerce su acción patógena y desarrollar otros enfoques en la búsqueda de nuevos antifúngicos. La revisión se realizó a través de los buscadores y plataformas HINARI , SciELO y MEDLINE . Se revisaron 40 revistas de impacto de la Web of Science relacionadas con el tema. Los descriptores empleados fueron: “genome of Candida albicans”, “drug resistance genes”, “dimorphism”, “virulence” y la combinación entre ellos y sus equivalentes en español. El análisis de los genomas fúngicos hace posible predecir el rol de genes con potencial terapéu - tico, con la secuenciación del genoma de Candida albicans ha aumentado la información sobre la función de los genes, entre los que destacan los posibles objetivos farmacológicos. El estudio del genoma de Candida albicans resulta imprescindible para diseñar en el futuro protocolos diagnósticos seguros, así como hallar nuevas dianas antifúngicas que permitan formular te - rapias más efectivas.

  8. Analgesic effects of crude extracts of Miconia albicans (Melastomataceae).

    Science.gov (United States)

    Vasconcelos, M A Lemos; Ferreira, D da Silva; Andrade e Silva, M L; Veneziani, R Cassio Sola; Cunha, W R

    2003-10-01

    The present study describes the analgesic effects of the crude extracts (hexane, methylene chloride and ethanol) obtained from the aerial parts of Miconia albicans (Melastomataceae) using the writhing test and the hot plate models for pain in mice. The extracts in hexane and methylene chloride, given orally, produced significant antinociception in the writhing test. On the other hand, none of the extracts had a significant effect on the hot plate test, a fact suggesting that the substances present in the extracts may rather have peripheral analgesic activity.

  9. Screening antioxidant and anticholinesterase potential of Iris albicans extracts

    OpenAIRE

    Işıl Hacıbekiroğlu; Ufuk Kolak

    2015-01-01

    The antioxidant and anticholinesterase activities of the extracts prepared from the rhizomes and flowering aerial parts of Iris albicans were determined in this study. The chloroform extract of the rhizomes was rich in total phenolic contents (431.98 ± 0.49 μgPEs/mg), and the chloroform extract of the aerial parts in total flavonoid contents (663.05 ± 0.32 μgQEs/mg). Although the chloroform extract of the rhizomes exhibited the best antioxidant effect in β -carotene bleaching and CUPRAC metho...

  10. Candida albicans septicemia in a premature infant successfully treated with oral fluconazole

    DEFF Research Database (Denmark)

    Bodé, S; Pedersen-Bjergaard, Lars; Hjelt, K

    1992-01-01

    A premature male infant, birth-weight 1460 g, was treated successfully for a Candida albicans septicemia with orally administered fluconazole for 20 days. Dosage was 5 mg/kg/day. No side effects were seen. Fluconazole may present a major progress in treatment of invasive C. albicans infections in...... in neonatology....

  11. Differentiation between Candida albicans and Candida dubliniensis using hypertonic Sabouraud broth and tobacco agar

    Directory of Open Access Journals (Sweden)

    Fabíola Silveira-Gomes

    2011-08-01

    Full Text Available INTRODUCTION: Opportunistic fungal infections in immunocompromised hosts are caused by Candida species, and the majority of such infections are due to Candida albicans. However, the emerging pathogen Candida dubliniensis demonstrates several phenotypic characteristics in common with C. albicans, such as production of germ tubes and chlamydospores, calling attention to the development of stable resistance to fluconazole in vitro. The aim of this study was to evaluate the performance of biochemistry identification in the differentiating between C. albicans and C. dubliniensis, by phenotyping of yeast identified as C. albicans. METHODS: Seventy-nine isolates identified as C. albicans by the API system ID 32C were grown on Sabouraud dextrose agar at 30°C for 24-48h and then inoculated on hypertonic Sabouraud broth and tobacco agar. RESULTS: Our results showed that 17 (21.5% isolates were growth-inhibited on hypertonic Sabouraud broth, a phenotypic trait inconsistent with C. albicans in this medium. However, the results observed on tobacco agar showed that only 9 (11.4% of the growth-inhibited isolates produced characteristic colonies of C. dubliniensis (rough colonies, yellowish-brown with abundant fragments of hyphae and chlamydospores. CONCLUSIONS: The results suggest that this method is a simple tool for screening C. albicans and non-albicans yeast and for verification of automated identification.

  12. Candida albicans septicemia in a premature infant successfully treated with oral fluconazole

    DEFF Research Database (Denmark)

    Bodé, S; Pedersen-Bjergaard, Lars; Hjelt, K

    1992-01-01

    A premature male infant, birth-weight 1460 g, was treated successfully for a Candida albicans septicemia with orally administered fluconazole for 20 days. Dosage was 5 mg/kg/day. No side effects were seen. Fluconazole may present a major progress in treatment of invasive C. albicans infections...

  13. The efficacy of crude extract of Aloe secundiflora on Candida Albicans

    African Journals Online (AJOL)

    In- vitro studies on the efficacy of crude extracts of Aloe secundiflora on Candida albicans was conducted. Five mature leaves of Aloe secundiflora were collected and the crude extract was prepared, then autoclaved. The extract was then tested on Candida albicans grown on solid media. The results from these studies ...

  14. Effect of 5-aminolevulinic acid photodynamic therapy on Candida albicans biofilms: An in vitro study.

    Science.gov (United States)

    Shi, Hang; Li, Jiyang; Zhang, Hui; Zhang, Jie; Sun, Hongying

    2016-09-01

    In this study, the photoinactivation of 5-aminolevulinic acid (ALA) has been investigated on Candida albicans biofilms in vitro. After culture and proliferation of Candida albicans biofilms in vitro, the metabolic activity was confirmed using XTT reduction assay. Then, the suitable incubation time and concentration of ALA were determined by measuring PpIX accumulation quantities. Photosensitivity of the biofilms treated with ALA solution was studied in optical doses of 50, 100, 200 and 300J/cm(2) while light irradiation was applied by a red light semiconductor. Finally, rapid immunofluorescence staining method using the LIVE/DEAD FungaLight Yeast Viability Kit and XTT assay were conducted to visualize and quantify the antifungal effect of ALA-PDT on Candida albicans biofilms. A 5h incubation time and 15mM ALA concentration were determined for this study. Photoinactivation of ALA-PDT on Candida albicans biofilms showed a significant increase of protoporphyrin IX (PpIX) in the biofilms. The metabolic activity of Candida albicans biofilms tread with ALA-PDT confirmed the inhibition efficacy compared with control groups. Upon radiation at 300J/cm(2), cells in Candida albicans biofilms were 74.45% inhibited. PpIX can be absorbed in biofilm-grown Candida albicans in vitro and under appropriate parameters, photochemistry can be triggered by light in combination with ALA and inhibits Candida albicans biofilms effectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Manipulation of host diet to reduce gastrointestinal colonization by the opportunistic pathogen Candida albicans

    Science.gov (United States)

    Candida albicans, the most common human fungal pathogen, can cause systemic infections with a mortality rate of ~40%. Infections arise from colonization of the gastrointestinal (GI) tract, where C. albicans is part of the normal microflora. Reducing colonization in at-risk patients using antifungal ...

  16. Dynamic Transcript Profiling of Candida albicans Infection in Zebrafish: A Pathogen-Host Interaction Study

    Science.gov (United States)

    Liu, Fu-Chen; Hsu, Po-Chen; Chen, Hsueh-Fen; Peng, Shih-Chi; Chuang, Yung-Jen; Lan, Chung-Yu; Hsieh, Wen-Ping; Wong, David Shan Hill

    2013-01-01

    Candida albicans is responsible for a number of life-threatening infections and causes considerable morbidity and mortality in immunocompromised patients. Previous studies of C. albicans pathogenesis have suggested several steps must occur before virulent infection, including early adhesion, invasion, and late tissue damage. However, the mechanism that triggers C. albicans transformation from yeast to hyphae form during infection has yet to be fully elucidated. This study used a systems biology approach to investigate C. albicans infection in zebrafish. The surviving fish were sampled at different post-infection time points to obtain time-lapsed, genome-wide transcriptomic data from both organisms, which were accompanied with in sync histological analyses. Principal component analysis (PCA) was used to analyze the dynamic gene expression profiles of significant variations in both C. albicans and zebrafish. The results categorized C. albicans infection into three progressing phases: adhesion, invasion, and damage. Such findings were highly supported by the corresponding histological analysis. Furthermore, the dynamic interspecies transcript profiling revealed that C. albicans activated its filamentous formation during invasion and the iron scavenging functions during the damage phases, whereas zebrafish ceased its iron homeostasis function following massive hemorrhage during the later stages of infection. Most of the immune related genes were expressed as the infection progressed from invasion to the damage phase. Such global, inter-species evidence of virulence-immune and iron competition dynamics during C. albicans infection could be crucial in understanding control fungal pathogenesis. PMID:24019870

  17. A novel immunocompetent murine model for Candida albicans-promoted oral epithelial dysplasia.

    Science.gov (United States)

    Dwivedi, P P; Mallya, S; Dongari-Bagtzoglou, A

    2009-03-01

    Candida albicans is a common opportunistic pathogen found in the oral mucosa. Clinical observations indicate a significant positive association between oral Candida carriage or infection and oral epithelial dysplasia/neoplasia. The aim of this study was to test whether C. albicans is able to promote epithelial dysplasia or carcinoma in a mouse model of infection where a carcinogen (4 Nitroquinoline 1-oxide [4NQO]) was used as initiator of neoplasia. Mice were divided into four groups: group 1 received 4NQO alone; group 2 received 4NQO followed by C. albicans (ATCC 90234); group 3 received vehicle dimethyl sulfoxide (DMSO) followed by C. albicans and group 4 was untreated. Although 4NQO treated mice did not develop oral lesions, mice exposed to both 4NQO and C. albicans developed oral dysplastic lesions 19 weeks after exposure to 4NQO. Mice challenged with C. albicans only developed hyperplastic lesions. The expression of Ki-67 and p16, two cell-cycle associated proteins that are frequently deregulated in oral dysplasia/neoplasia, was also tested in these lesions. Ki-67 and p16 expression increased from normal to hyperplastic to dysplastic mucosa and was highest in the group exposed to both 4NQO and C. albicans. In conclusion, we showed that C. albicans plays a role in the promotion of oral dysplasia in a mouse model of infection when 4NQO was used as initiator of oral neoplasia.

  18. Stability of candida albicans over long and short term storage in a ...

    African Journals Online (AJOL)

    We thus,set out to study the stability of Candida albicans over long and short term storage in a resource-limited setting. METHODS: One hundred Candida albicans strains isolated from patients with vulvovaginal candidiasis and oral candidiasis were preserved in triplicates using sterile distilled water,Chromagar plate ...

  19. Efek Penambahan Glukosa pada Saburoud Dextrose Broth terhadap Pertumbuhan Candida albicans (Uji In Vitro

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    Lakshmi A. Leepel

    2012-10-01

    Full Text Available High carbohydrate intake is one of predisposing factors of oral candidiasis. Objective: Investigating the effect of 1%,5%,10% glucose addition on the growth of C.albicans in vitro. Method: C.albicans sample was taken from oral swab of a male oral candidiasis patient. Identification of C.albicans was conducted using CHROMagar and confirmed by germ tube formation in serum. As a comparison, C.albicans ATCC10231 was used. After 2 days the cultures were serially diluted and inoculated in SDB without glucose, and with 1%,5%,10% addditional glucose, kept for 3 and 7 days in room temperature, then inoculated in SDA. The CFU/ml were counted after 2 days. ANOVA with α0.05 was used. Result: Statisticaly, additional 1% glucose for 3 days lead to significant decreased of growth of both clinical strain and ATCC 10231 C. albicans. However, only additional 5% and 10% glucose in clinical isolate for 7 days increased the growth of C.albicans significantly. Conclusion: The effect of additional glucose on the increased growth of C.albicans in vitro is influenced by the concentration, exposure duration of glucose, and by the strain of C.albicans.DOI: 10.14693/jdi.v16i1.14

  20. Quantitative relationships of Candida albicans infections and dressing patterns in Nigerian women.

    Science.gov (United States)

    Elegbe, I A; Elegbe, I

    1983-04-01

    Candida albicans colony counts were far higher in patients with vaginitis wearing tight fitting clothing than in patients wearing loose fitting clothing. In Ile-Ife, Nigeria, tight fitting dresses, woolen and corduroy jeans, coupled with nylon underwear, appear to create an environment favorable to Candida albicans colonization.

  1. The efficacy of gaseous ozone against different forms of Candida albicans

    Directory of Open Access Journals (Sweden)

    Mahdis Zargaran

    2017-06-01

    Conclusion: Although ozone was highly effective on the yeast form of C. albicans and it can inhibit the formation of germ tubes in C. albicans, the complete removal of biofilms did not happen even after 60 min. It seems that ozone therapy induces resistance to amphotericin B.  

  2. Differentiation between Candida albicans and Candida dubliniensis using hypertonic Sabouraud broth and tobacco agar.

    Science.gov (United States)

    Silveira-Gomes, Fabíola; Sarmento, Dayse Nogueira; Espírito-Santo, Elaine Patrícia Tavares do; Souza, Nádia de Oliveira; Pinto, Thifany Mendes; Marques-da-Silva, Silvia Helena

    2011-01-01

    Opportunistic fungal infections in immunocompromised hosts are caused by Candida species, and the majority of such infections are due to Candida albicans. However, the emerging pathogen Candida dubliniensis demonstrates several phenotypic characteristics in common with C. albicans, such as production of germ tubes and chlamydospores, calling attention to the development of stable resistance to fluconazole in vitro. The aim of this study was to evaluate the performance of biochemistry identification in the differentiating between C. albicans and C. dubliniensis, by phenotyping of yeast identified as C. albicans. Seventy-nine isolates identified as C. albicans by the API system ID 32C were grown on Sabouraud dextrose agar at 30°C for 24-48h and then inoculated on hypertonic Sabouraud broth and tobacco agar. Our results showed that 17 (21.5%) isolates were growth-inhibited on hypertonic Sabouraud broth, a phenotypic trait inconsistent with C. albicans in this medium. However, the results observed on tobacco agar showed that only 9 (11.4%) of the growth-inhibited isolates produced characteristic colonies of C. dubliniensis (rough colonies, yellowish-brown with abundant fragments of hyphae and chlamydospores). The results suggest that this method is a simple tool for screening C. albicans and non-albicans yeast and for verification of automated identification.

  3. Comparison of Adherence of Candida Albicans on Amalgam, Light Cure Composite and Glass Ionomer: an In vitro Study

    OpenAIRE

    Azizi A.; Falahati M.; Heshmat H.; Entezari N.

    2011-01-01

    Statement of Problem: Candidiasis is the most common fungal infection in the human oral cavity. 85% of this infection is caused by Candida albicans. Although there is considerable information about the adhesion of Candida albicans to the epithelial cells and prosthetic materials, there are very few studies in regard to the adhesion of Candida albicans to various restorative dental materials.Purpose: This study aimed to compare the adhesion of Candida albicans to three restorative materials, a...

  4. Candida albicans Carriage in Children with Severe Early Childhood Caries (S-ECC and Maternal Relatedness.

    Directory of Open Access Journals (Sweden)

    Jin Xiao

    Full Text Available Candida albicans has been detected together with Streptococcus mutans in high numbers in plaque-biofilm from children with early childhood caries (ECC. The goal of this study was to examine the C. albicans carriage in children with severe early childhood caries (S-ECC and the maternal relatedness.Subjects in this pilot cross-sectional study were recruited based on a convenient sample. DMFT(S/dmft(s caries and plaque scores were assessed during a comprehensive oral exam. Social-demographic and related background information was collected through a questionnaire. Saliva and plaque sample from all children and mother subjects were collected. C. albicans were isolated by BBL™ CHROMagar™ and also identified using germ tube test. S. mutans was isolated using Mitis Salivarius with Bacitracin selective medium and identified by colony morphology. Genetic relatedness was examined using restriction endonuclease analysis of the C. albicans genome using BssHII (REAG-B. Multilocus sequence typing was used to examine the clustering information of isolated C. albicans. Spot assay was performed to examine the C. albicans Caspofungin susceptibility between S-ECC children and their mothers. All statistical analyses (power analysis for sample size, Spearman's correlation coefficient and multiple regression analyses were implemented with SAS 9.4.A total of 18 S-ECC child-mother pairs and 17 caries free child-mother pairs were enrolled in the study. Results indicated high C. albicans carriage rate in the oral cavity (saliva and plaque of both S-ECC children and their mothers (>80%. Spearman's correlation coefficient also indicated a significant correlation between salivary and plaque C. albicans and S. mutans carriage (p60% of them demonstrated identical C. albicans REAG-B pattern. C. albicans isolated from >65% of child-mother pairs demonstrated similar susceptibility to caspofungin in spot assay, while no caspofungin resistant strains were seen when compared

  5. Candida albicans Carriage in Children with Severe Early Childhood Caries (S-ECC) and Maternal Relatedness.

    Science.gov (United States)

    Xiao, Jin; Moon, Yonghwi; Li, Lihua; Rustchenko, Elena; Wakabayashi, Hironao; Zhao, Xiaoyi; Feng, Changyong; Gill, Steven R; McLaren, Sean; Malmstrom, Hans; Ren, Yanfang; Quivey, Robert; Koo, Hyun; Kopycka-Kedzierawski, Dorota T

    2016-01-01

    Candida albicans has been detected together with Streptococcus mutans in high numbers in plaque-biofilm from children with early childhood caries (ECC). The goal of this study was to examine the C. albicans carriage in children with severe early childhood caries (S-ECC) and the maternal relatedness. Subjects in this pilot cross-sectional study were recruited based on a convenient sample. DMFT(S)/dmft(s) caries and plaque scores were assessed during a comprehensive oral exam. Social-demographic and related background information was collected through a questionnaire. Saliva and plaque sample from all children and mother subjects were collected. C. albicans were isolated by BBL™ CHROMagar™ and also identified using germ tube test. S. mutans was isolated using Mitis Salivarius with Bacitracin selective medium and identified by colony morphology. Genetic relatedness was examined using restriction endonuclease analysis of the C. albicans genome using BssHII (REAG-B). Multilocus sequence typing was used to examine the clustering information of isolated C. albicans. Spot assay was performed to examine the C. albicans Caspofungin susceptibility between S-ECC children and their mothers. All statistical analyses (power analysis for sample size, Spearman's correlation coefficient and multiple regression analyses) were implemented with SAS 9.4. A total of 18 S-ECC child-mother pairs and 17 caries free child-mother pairs were enrolled in the study. Results indicated high C. albicans carriage rate in the oral cavity (saliva and plaque) of both S-ECC children and their mothers (>80%). Spearman's correlation coefficient also indicated a significant correlation between salivary and plaque C. albicans and S. mutans carriage (p60% of them demonstrated identical C. albicans REAG-B pattern. C. albicans isolated from >65% of child-mother pairs demonstrated similar susceptibility to caspofungin in spot assay, while no caspofungin resistant strains were seen when compared with C

  6. Pharmacoeconomic analysis of antifungal therapy for primary treatment of invasive candidiasis caused by Candida albicans and non-albicans Candida species.

    Science.gov (United States)

    Ou, Huang-Tz; Lee, Tsung-Ying; Chen, Yee-Chun; Charbonneau, Claudie

    2017-07-10

    Cost-effectiveness studies of echinocandins for the treatment of invasive candidiasis, including candidemia, are rare in Asia. No study has determined whether echinocandins are cost-effective for both Candida albicans and non-albicans Candida species. There have been no economic evaluations that compare non-echinocandins with the three available echinocandins. This study was aimed to assess the cost-effectiveness of individual echinocandins, namely caspofungin, micafungin, and anidulafungin, versus non-echinocandins for C. albicans and non-albicans Candida species, respectively. A decision tree model was constructed to assess the cost-effectiveness of echinocandins and non-echinocandins for invasive candidiasis. The probability of treatment success, mortality rate, and adverse drug events were extracted from published clinical trials. The cost variables (i.e., drug acquisition) were based on Taiwan's healthcare system from the perspective of a medical payer. One-way sensitivity analyses and probability sensitivity analyses were conducted. For treating invasive candidiasis (all species), as compared to fluconazole, micafungin and caspofungin are dominated (less effective, more expensive), whereas anidulafungin is cost-effective (more effective, more expensive), costing US$3666.09 for each life-year gained, which was below the implicit threshold of the incremental cost-effectiveness ratio in Taiwan. For C. albicans, echinocandins are cost-saving as compared to non-echinocandins. For non-albicans Candida species, echinocandins are cost-effective as compared to non-echinocandins, costing US$652 for each life-year gained. The results were robust over a wide range of sensitivity analyses and were most sensitive to the clinical efficacy of antifungal treatment. Echinocandins, especially anidulafungin, appear to be cost-effective for invasive candidiasis caused by C. albicans and non-albicans Candida species in Taiwan.

  7. Detection of phospholipase activity of Candida albicans and non albicans isolated from women of reproductive age with vulvovaginal candidiasis in rural area

    Directory of Open Access Journals (Sweden)

    S R Fule

    2015-01-01

    Full Text Available Background: Vulvovaginal candidiasis (VVC is most common accounting for 17 to 39% of symptomatic women. Both Candida albicans and non albicans Candida species are involved in VVC. Amongst various virulence factors proposed for Candida, extracellular phospholipases is one of the virulence factor implicated in its pathogenicity. With this background the present study was carried out to find the prevalence of different Candida species and to detect phospholipase producing strains isolated from symptomatic women with VVC. Materials and Methods: At least two vaginal swabs from 156 women of reproductive age with abnormal vaginal discharge were collected. Direct microscopy and Gram′s stained smear examined for presence of budding yeast and pseudo mycelia followed by isolation and identification of Candida species. Extracellular phospholipase activity was studied by inoculating all isolates on Sabouraud′s dextrose egg yolk agar (SDA medium. Results: Of the 156 women with curdy white discharge alone or in combination with other signs, 59 (37.82% women showed laboratory evidence of VVC. A total of 31 (52.54% women had curdy white discharge followed by 12 (20.33% with other signs and symptoms. C. albicans (62.59% and non albicans Candida (37.28% in a ratio of 1.68:1 were isolated. Of the 37 strains of C. albians 30 (81.08% showed the enzyme activity. Seventeen (56.66% strains showed higher Pz value of < 0.70 (++++. Conclusion: Although there may be typical clinical presentation of Candidiasis. all the patients did not show laboratory evidence of infection. Pregnancy was found to be major risk factor for development of VVC. C. albicans was prevalent species but non albicans species were also frequently isolated. Extracellular phospholipase activity was seen in C. albicans and not in non albicans Candida isolates.

  8. Antimicrobial effects of Coleus amboinicus, Lour folium infusum towards Candida albicans and Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Devi Rianti

    2006-03-01

    Full Text Available A laboratory experimental study conducted on antimicrobial effects of Coleus amboinicus, Lour folium Infusum towards Candida albicans and Streptococcus mutans (S. mutans. Effective concentration of Coleus amboinicus, Lour to decrease the quantities Candida albicans and S. mutans colonies is expected to be found out in this study. This study was using Coleus Amboinicus, Lour folium infusum with 12.5%, 15%, 17.5%, 20%, and 22.5% concentrations. Sterilized aquadest used as a control. Candida albicans and S. mutans quantities was enumerated by counting the amount of Candida albicans and S. mutans growth in the Sabouraud ,s dextrose agar and Tryptone and yeast Agar media, using Colony Forming Unit per milliliter (CFU/ ml unit. Data analysis was using a One-Way ANOVA and LSD with 5% degree of significance. The result showed 22.5% concentration of CAL folium infusum was the most effective in decreasing the quantity Candida albicans and S. mutans colonies.

  9. Candida albicans orf19.3727 encodes phytase activity and is essential for human tissue damage.

    Directory of Open Access Journals (Sweden)

    Paul Wai-Kei Tsang

    Full Text Available Candida albicans is a clinically important human fungal pathogen. We previously identified the presence of cell-associated phytase activity in C. albicans. Here, we reveal for the first time, that orf19.3727 contributes to phytase activity in C. albicans and ultimately to its virulence potency. Compared with its wild type counterpart, disruption of C. albicans orf19.3727 led to decreased phytase activity, reduced ability to form hyphae, attenuated in vitro adhesion, and reduced ability to penetrate human epithelium, which are the major virulence attributes of this yeast. Thus, orf19.3727 of C. albicans plays a key role in fungal pathogenesis. Further, our data uncover a putative novel strategy for anti-Candidal drug design through inhibition of phytase activity of this common pathogen.

  10. Immunosensing during colonization by Candida albicans: does it take a village to colonize the intestine?

    Science.gov (United States)

    Kumamoto, Carol A; Pierce, Jessica V

    2011-06-01

    Candida albicans, an opportunistic fungal pathogen and a component of the normal flora of the gastrointestinal tract, is a frequent colonizer of humans. Is C. albicans capable of sensing the immune status of its host, a process we term immunosensing, and, if so, how? C. albicans causes serious disease only in immunocompromised hosts and therefore the ability to immunosense would be advantageous to an organism. We propose a speculative model whereby, during colonization, C. albicans produces phenotypic variants that vary in relative concentration depending on host status. One variant is optimized for persistence as a commensal, whereas the other variant has higher capacity to initiate pathogenic interactions. When the ratio of the two variants changes, the pathogenic potential of the population changes. The critical element of this model is that the C. albicans colonizing population is not uniform but is composed of subpopulations of phenotypic variants that are advantageous under different host conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Candida dubliniensis and Candida albicans differentiation by colony morphotype in Sabouraud-triphenyltetrazolium agar.

    Science.gov (United States)

    Gamarra, Soledad; Mancilla, Estefanía; Dudiuk, Catiana; Garcia-Effron, Guillermo

    2015-01-01

    Candida dubliniensis is a germ tube and chlamydoconidia producing Candida species that may be misidentified as Candida albicans. Molecular-based methods are the most reliable techniques for C. albicans and C. dubliniensis differentiation. However, accurate, quick and inexpensive phenotypic tests are needed to be used in low-complexity mycology laboratories. To evaluate colony morphotypes on Sabouraud-triphenyltetrazolium agar as a tool for C. dubliniensis and C. albicans differentiation. The morphology of 126 C. albicans and C. dubliniensis strains was evaluated and compared with their identification by molecular methods. The method showed 100% sensitivity and specificity when color and the presence or absence of large white mycelial halo was evaluated. Colony morphotype on Sabouraud-triphenyltetrazolium agar should be considered as a new tool to differentiate C. dubliniensis and C. albicans. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  12. A Case Report of Penile Infection Caused by Fluconazole- and Terbinafine-Resistant Candida albicans.

    Science.gov (United States)

    Hu, Yongxuan; Hu, Yanqing; Lu, Yan; Huang, Shiyun; Liu, Kangxing; Han, Xue; Mao, Zuhao; Wu, Zhong; Zhou, Xianyi

    2017-04-01

    Candida albicans is the most common pathogen that causes balanoposthitis. It often causes recurrence of symptoms probably due to its antifungal resistance. A significant number of balanitis Candida albicans isolates are resistant to azole and terbinafine antifungal agents in vitro. However, balanoposthitis caused by fluconazole- and terbinafine-resistant Candida albicans has rarely been reported. Here, we describe a case of a recurrent penile infection caused by fluconazole- and terbinafine-resistant Candida albicans, as well as the treatments administered to this patient. The isolate from the patient was tested for drug susceptibility in vitro. It was sensitive to itraconazole, voriconazole, clotrimazole and amphotericin B, but not to terbinafine and fluconazole. Thus, oral itraconazole was administrated to this patient with resistant Candida albicans penile infection. The symptoms were improved, and mycological examination result was negative. Follow-up treatment of this patient for 3 months showed no recurrence.

  13. Liquid and vapour-phase antifungal activities of essential oils against Candida albicans and non-albicans Candida.

    Science.gov (United States)

    Mandras, Narcisa; Nostro, Antonia; Roana, Janira; Scalas, Daniela; Banche, Giuliana; Ghisetti, Valeria; Del Re, Simonetta; Fucale, Giacomo; Cuffini, Anna Maria; Tullio, Vivian

    2016-08-30

    The management of Candida infections faces many problems, such as a limited number of antifungal drugs, toxicity, resistance of Candida to commonly antifungal drugs, relapse of Candida infections, and the high cost of antifungal drugs. Though azole antifungal agents and derivatives continue to dominate as drugs of choice against Candida infections, there are many available data referring to the anticandidal activity of essential oils. Since we have previous observed a good antimicrobial activity of some essential oils against filamentous fungi, the aim of this study was to extend the research to evaluate the activity of the same oils on Candida albicans, C.glabrata and C.tropicalis clinical strains, as well as the effects of related components. Essential oils selection was based both on ethnomedicinal use and on proved antibacterial and/or antifungal activity of some of these oils. Fluconazole and voriconazole were used as reference drugs. The minimum inhibitory concentration (MIC) and the minimal fungicidal concentration (MFC) of essential oils (thyme red, fennel, clove, pine, sage, lemon balm, and lavender) and their major components were investigated by the broth microdilution method (BM) and the vapour contact assay (VC). Using BM, pine oil showed the best activity against all strains tested, though C.albicans was more susceptible than C.glabrata and C.tropicalis (MIC50-MIC90 = 0.06 %, v/v). On the contrary, sage oil displayed a weak activity (MIC50-MIC90 = 1 %, v/v). Thyme red oil (MIC50-MIC90 ≤ 0.0038 %, v/v for C.albicans and C.tropicalis, and 0.0078- Candida spp., including fluconazole/voriconazole resistant strains. These data encourage adequately controlled and randomized clinical investigations. The use in vapour phase could have additional advantages without requiring direct contact, resulting in easy of environmental application such as in hospital, and/or in school.

  14. Sequence variations and protein expression levels of the two immune evasion proteins Gpm1 and Pra1 influence virulence of clinical Candida albicans isolates.

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    Shanshan Luo

    Full Text Available Candida albicans, the important human fungal pathogen uses multiple evasion strategies to control, modulate and inhibit host complement and innate immune attack. Clinical C. albicans strains vary in pathogenicity and in serum resistance, in this work we analyzed sequence polymorphisms and variations in the expression levels of two central fungal complement evasion proteins, Gpm1 (phosphoglycerate mutase 1 and Pra1 (pH-regulated antigen 1 in thirteen clinical C. albicans isolates. Four nucleotide (nt exchanges, all representing synonymous exchanges, were identified within the 747-nt long GPM1 gene. For the 900-nt long PRA1 gene, sixteen nucleotide exchanges were identified, which represented synonymous, as well as non-synonymous exchanges. All thirteen clinical isolates had a homozygous exchange (A to G at position 73 of the PRA1 gene. Surface levels of Gpm1 varied by 8.2, and Pra1 levels by 3.3 fold in thirteen tested isolates and these differences influenced fungal immune fitness. The high Gpm1/Pra1 expressing candida strains bound the three human immune regulators more efficiently, than the low expression strains. The difference was 44% for Factor H binding, 51% for C4BP binding and 23% for plasminogen binding. This higher Gpm1/Pra1 expressing strains result in enhanced survival upon challenge with complement active, Factor H depleted human serum (difference 40%. In addition adhesion to and infection of human endothelial cells was increased (difference 60%, and C3b surface deposition was less effective (difference 27%. Thus, variable expression levels of central immune evasion protein influences immune fitness of the human fungal pathogen C. albicans and thus contribute to fungal virulence.

  15. The secreted Candida albicans protein Pra1 disrupts host defense by broadly targeting and blocking complement C3 and C3 activation fragments.

    Science.gov (United States)

    Luo, Shanshan; Dasari, Prasad; Reiher, Nadine; Hartmann, Andrea; Jacksch, Susanne; Wende, Elisabeth; Barz, Dagmar; Niemiec, Maria Joanna; Jacobsen, Ilse; Beyersdorf, Niklas; Hünig, Thomas; Klos, Andreas; Skerka, Christine; Zipfel, Peter F

    2018-01-01

    Candida albicans the most frequently isolated clinical fungal pathogen can cause local as well as systemic and life-threatening infections particularly in immune-compromised individuals. A better and more detailed understanding how C. albicans evades human immune attack is therefore needed for identifying fungal immune-evasive proteins and develop new therapies. Here, we identified Pra1, the pH-regulated C. albicans antigen as a hierarchical complement inhibitor that targets C3, the central human complement component. Pra1 cleaved C3 at a unique site and further inhibited effector function of the activation fragments. The newly formed C3a-like peptide lacked the C-terminal arginine residue needed for C3a-receptor binding and activation. Moreover, Pra1 also blocked C3a-like antifungal activity as shown in survival assays, and the C3b-like molecule formed by Pra1 was degraded by the host protease Factor I. Pra1 also bound to C3a and C3b generated by human convertases and blocked their effector functions, like C3a antifungal activity shown by fungal survival, blocked C3a binding to human C3a receptor-expressing HEK cells, activation of Fura2-AM loaded cells, intracellular Ca 2+ signaling, IL-8 release, C3b deposition, as well as opsonophagocytosis and killing by human neutrophils. Thus, upon infection C. albicans uses Pra1 to destroy C3 and to disrupt host complement attack. In conclusion, candida Pra1 represents the first fungal C3-cleaving protease identified and functions as a fungal master regulator of innate immunity and as a central fungal immune-escape protein. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Sequence variations and protein expression levels of the two immune evasion proteins Gpm1 and Pra1 influence virulence of clinical Candida albicans isolates.

    Science.gov (United States)

    Luo, Shanshan; Hipler, Uta-Christina; Münzberg, Christin; Skerka, Christine; Zipfel, Peter F

    2015-01-01

    Candida albicans, the important human fungal pathogen uses multiple evasion strategies to control, modulate and inhibit host complement and innate immune attack. Clinical C. albicans strains vary in pathogenicity and in serum resistance, in this work we analyzed sequence polymorphisms and variations in the expression levels of two central fungal complement evasion proteins, Gpm1 (phosphoglycerate mutase 1) and Pra1 (pH-regulated antigen 1) in thirteen clinical C. albicans isolates. Four nucleotide (nt) exchanges, all representing synonymous exchanges, were identified within the 747-nt long GPM1 gene. For the 900-nt long PRA1 gene, sixteen nucleotide exchanges were identified, which represented synonymous, as well as non-synonymous exchanges. All thirteen clinical isolates had a homozygous exchange (A to G) at position 73 of the PRA1 gene. Surface levels of Gpm1 varied by 8.2, and Pra1 levels by 3.3 fold in thirteen tested isolates and these differences influenced fungal immune fitness. The high Gpm1/Pra1 expressing candida strains bound the three human immune regulators more efficiently, than the low expression strains. The difference was 44% for Factor H binding, 51% for C4BP binding and 23% for plasminogen binding. This higher Gpm1/Pra1 expressing strains result in enhanced survival upon challenge with complement active, Factor H depleted human serum (difference 40%). In addition adhesion to and infection of human endothelial cells was increased (difference 60%), and C3b surface deposition was less effective (difference 27%). Thus, variable expression levels of central immune evasion protein influences immune fitness of the human fungal pathogen C. albicans and thus contribute to fungal virulence.

  17. Cell wall proteinaceous components in isolates of Candida albicans and non-albicans species from HIV-infected patients with oropharyngeal candidiasis.

    Science.gov (United States)

    López-Ribot, J L; Kirkpatrick, W R; McAtee, R K; Revankar, S G; Patterson, T F

    1998-09-01

    Oropharyngeal candidiasis (OPC) remains a common opportunistic infection in HIV-infected patients. Candida albicans is the most frequent causative agent of OPC. However, non-albicans spp. are being increasingly isolated. Candidal cell wall proteins and mannoproteins play important roles in the biology and patogenesis of candidiasis. In the present study, we have analyzed the proteinaceous components associated with cell wall extracts from C. albicans, Candida tropicalis, Candida pseudotropicalis, Candida krusei, Candida glabrata, Candida parapsilosis, Candida guilliermondii and Candida rugosa obtained from HIV-infected patients with recurrent OPC. Cell wall proteinaceous components were extracted with beta-mercaptoethanol and analyzed using electrophoresis, immunoblotting (with antisera generated against C. albicans cell wall components, and with serum samples and oral saline rinses from patients with OPC), and lectin-blotting (concanavalin A) techniques. Numerous molecular species were solubilized from the various isolates. Major qualitative and quantitative differences in the polypeptidic and antigenic profiles associated with the cell wall extracts from the different Candida spp. were discernible. Some of the antibody preparations generated against C. albicans cell wall components were able to recognize homologous materials present in the extracts from non-albicans spp. Information on cell wall antigens of Candida species may be important in the therapy and prevention of HIV-related OPC.

  18. [The effects of an aroma candy on oral Candida albicans colony-forming units (CFU) and oral hygiene states in healthy elderly carrying Candida albicans].

    Science.gov (United States)

    Suzuki, Motofumi; Hayama, Kazumi; Takahashi, Miki; Ezawa, Kunio; Yamazaki, Masatoshi; Matsukawa, Taiji; Kishi, Akinobu; Satou, Nobuya; Abe, Shigeru

    2015-01-01

    In a preceding paper, we showed that aroma candy containing oligonol, capric acid, and cinnamon (cassia) powder had potent inhibitory activity against mycelial growth of Candida albicans in vitro and protective activity against murine oral candidiasis. In order to assess the effects of this candy (the test candy) on oral C. albicans colony-forming units (CFU) and oral hygiene states, a placebo-controlled double-blind crossover comparative study was performed. Twenty subjects were divided into two groups. One group ingested the test candy in the first 7 days followed by 2 weeks washing-off period, then ingested the placebo candy (control candy) for 7 days. The other group was vice versa. C. albicans CFU in all oral rinse samples from the subjects before and after 7 days ingestion of candy was measured. The degree of oral malodor in all subjects was monitored using a portable measuring instrument. The results showed no statistically significant difference between test-candy group and placebo group for C. albicans CFU. However, C. albicans CFU in test-candy group with>4,000 CFUs was significantly decreased after 7 days ingestion of test-candy (poral malodor in the test-candy group was significantly decreased after 7 days ingestion of test-candy (poral hygiene states indicated that in the test-candy group, oral malodor, glutinous feeling, and refreshing feeling significantly improved in comparison with control-candy group (poral health care of elderly carrying C. albicans.

  19. Chloroquine sensitizes biofilms of Candida albicans to antifungal azoles

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    Ravikumar Bapurao Shinde

    Full Text Available Biofilms formed by Candida albicans, a human pathogen, are known to be resistant to different antifungal agents. Novel strategies to combat the biofilm associated Candida infections like multiple drug therapy are being explored. In this study, potential of chloroquine to be a partner drug in combination with four antifungal agents, namely fluconazole, voriconazole, amphotericin B, and caspofungin, was explored against biofilms of C. albicans. Activity of various concentrations of chloroquine in combination with a particular antifungal drug was analyzed in a checkerboard format. Growth of biofilm in presence of drugs was analyzed by XTT-assay, in terms of relative metabolic activity compared to that of drug free control. Results obtained by XTT-metabolic assay were confirmed by scanning electron microscopy. The interactions between chloroquine and four antifungal drugs were determined by calculating fractional inhibitory concentration indices. Azole resistance in biofilms was reverted significantly (p < 0.05 in presence of 250 µg/mL of chloroquine, which resulted in inhibition of biofilms at very low concentrations of antifungal drugs. No significant alteration in the sensitivity of biofilms to caspofungin and amphotericin B was evident in combination with chloroquine. This study for the first time indicates that chloroquine potentiates anti-biofilm activity of fluconazole and voriconazole.

  20. Candida albicans mannoprotein influences the biological function of dendritic cells.

    Science.gov (United States)

    Pietrella, Donatella; Bistoni, Giovanni; Corbucci, Cristina; Perito, Stefano; Vecchiarelli, Anna

    2006-04-01

    Cell wall components of fungi involved in induction of host immune response are predominantly proteins and glycoproteins, the latter being mainly mannoproteins (MP). In this study we analyse the interaction of the MP from Candida albicans (MP65) with dendritic cells (DC) and demonstrate that MP65 stimulates DC and induces the release of TNF-alpha, IL-6 and the activation of IL-12 gene, with maximal value 6 h post treatment. MP65 induces DC maturation by increasing costimulatory molecules and decreasing CD14 and FcgammaR molecule expression. The latter effect is partly mediated by toll-like receptor 2 (TLR2) and TLR4, and the MyD88-dependent pathway is involved in the process. MP65 enables DC to activate T cell response, its protein core is essential for induction of T cell activation, while its glycosylated portion primarily promotes cytokine production. The mechanisms involved in induction of protective response against C. albicans could be mediated by the MP65 antigen, suggesting that MP65 may be a suitable candidate vaccine.

  1. Candida albicans susceptibility to lactoperoxidase-generated hypoiodite

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    Mohamed Ahariz

    2010-08-01

    Full Text Available Mohamed Ahariz1, Philippe Courtois21Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Brussels, Belgium; 2Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Brussels, Belgium and UER de Biologie Médicale, Haute Ecole Francisco Ferrer, Brussels, BelgiumAbstract: In vivo, lactoperoxidase produces hypothiocyanite (OSCN- from thiocyanate (SCN- in the presence of hydrogen peroxide (H2O2; in vitro, iodide (I- can be oxidized into hypoiodite (OI- by this enzyme. The aim of this study was to compare in vitro the anti-Candida effect of iodide versus thiocyanate used as lactoperoxidase substrate to prevent Candida biofilms development. Candida albicans ATCC 10231 susceptibility upon both peroxidase systems was tested in three different experimental designs: (i in a liquid culture medium, (ii in an interface model between solid culture medium and gel containing the enzymic systems, (iii in a biofilm model onto titanium and acrylic resin. Yeast growth in liquid medium was monitored by turbidimetry at 600 nm. Material-adherent yeast biomass was evaluated by the tetrazolium salt MTT method. The iodide-peroxidase system has been shown to inhibit Candida biofilm formation at lower substrate concentrations (~200 fold less H2O2 donor and for longer incubation periods than the thiocyanate-peroxidase system. In conclusion, efficiency of lactoperoxidase-generated OI- to prevent C. albicans biofilm development allows refining iodine antifungal use in ex vivo conditions.Keywords: denture, iodide, oral, peroxidase, saliva, titanium

  2. Candida albicans spondylodiscitis following an abdominal stab wound: forensic considerations.

    Science.gov (United States)

    Savall, Frederic; Dedouit, Fabrice; Telmon, Norbert; Rougé, Daniel

    2014-03-01

    Candida albicans spondylodiscitis is a fungal infection of the spine which is still unusual in spite of the increasing frequency of predisposing factors. A 22-year-old man received an abdominal stab wound during a physical assault. Initial medical care included surgery, prolonged use of indwelling vascular catheters with administration of broad-spectrum antibiotics, and hospitalization in intensive care. Two months after the event, the victim experienced back pain in the right lumbar region and septic spondylodiscitis secondary to C. albicans was diagnosed three weeks later. This case is noteworthy because of its clinical forensic context. In France, the public prosecutor orders a medico-legal assessment after an assault for all living victims in order to establish a causal relationship between the assault and its complications. In our case, the patient presented numerous risk factors for candidemia and the forensic specialist reasonably accepted that the causal relationship was certain but indirect. We have only found one published case of spondylodiscitis after an abdominal penetrating injury and the pathogenic agent was not mentioned. We have found no case reported in a forensic context. This unusual observation shows that it may be genuinely difficult to prove the causal relationship between an abdominal penetrating injury and an unusual infectious complication such as fungal spondylodiscitis. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  3. Mechanism of iron uptake by the pathogenic yeast, Candida albicans

    International Nuclear Information System (INIS)

    Ismail, A.

    1986-01-01

    C. albicans requires iron for growth and phenotypic development. When deprived of iron, mycelium and bud formation was suppressed. Survival of the organism was also reduced under iron-limiting conditions. The combination of elevated temperature and iron-deprivation further reduced phenotypic development and survival of the yeast. The combination of elevated temperature and iron starvation resulted in a decrease in both the growth rate and siderophore production. However, with time, the cells were able to show partial recovery in the growth rate which occurred concomitantly with an increase in siderophore production. In order for siderophores to be utilized, ferri-siderophore receptors must be produced. The receptor was shown to be located in the plasma membrane of the yeast. Scatchard analysis of the binding of ferri-siderophores to plasma membrane receptors showed an increase in receptor affinity and number of binding sites in iron-starved cells when compared to control cells. Autoradiograms of the 58 Fe-siderophore-protein complex following SDS-PAGE separation of candidal proteins revealed the presence of a ferri-siderophore receptor of approximately 10,000 daltons. C. albicans strains which lacked the ability to synthesize phenolate siderophore maintained a phenolate receptor and bound candidal phenolate siderophore better than non-candidal phenolate siderophores

  4. Molecular methods for strain typing of Candida albicans: a review.

    Science.gov (United States)

    Saghrouni, F; Ben Abdeljelil, J; Boukadida, J; Ben Said, M

    2013-06-01

    Candida albicans is one of the most medically important fungi because of its high frequency as a commensal and pathogenic microorganism causing superficial as well as invasive infections. Strain typing and delineation of the species are essential for understanding its biology, epidemiology and population structure. A wide range of molecular techniques have been used for this purpose including non-DNA-based methods (multi-locus enzyme electrophoresis), conventional DNA-based methods (electrophoretic karyotyping, random amplified polymorphic DNA, amplified fragment length polymorphism, restriction enzyme analysis with and without hybridization, rep-PCR) and DNA-based methods called exact typing methods because they generate unambiguous and highly reproducible typing data (including microsatellite length polymorphism and multi-locus sequence typing). In this review, the main molecular methods used for C. albicans strain typing are summarized, and their advantages and limitations are discussed with regard to their discriminatory power, reproducibility, cost and ease of performance. © 2013 The Society for Applied Microbiology.

  5. Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis.

    Science.gov (United States)

    Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Vilela, Simone Furgeri Godinho; dos Santos, Jéssica Diane; de Barros, Patrícia Pimentel; Prata, Márcia Cristina de Azevedo; Anbinder, Ana Lia; Fuchs, Beth Burgwyn; Jorge, Antonio Olavo Cardoso; Mylonakis, Eleftherios; Junqueira, Juliana Campos

    2015-01-01

    In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis.

  6. Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis

    Science.gov (United States)

    Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Vilela, Simone Furgeri Godinho; dos Santos, Jéssica Diane; de Barros, Patrícia Pimentel; Prata, Márcia Cristina de Azevedo; Anbinder, Ana Lia; Fuchs, Beth Burgwyn; Jorge, Antonio Olavo Cardoso; Mylonakis, Eleftherios; Junqueira, Juliana Campos

    2015-01-01

    In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis. PMID:26146832

  7. The Anti-Adhesive Effect of Curcumin on Candida albicans Biofilms on Denture Materials

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    Gordon Ramage

    2017-04-01

    Full Text Available The use of natural compounds as an alternative source of antimicrobials has become a necessity given the growing concern over global antimicrobial resistance. Polyphenols, found in various edible plants, offers one potential solution to this. We aimed to investigate the possibility of using curcumin within the context of oral health as a way of inhibiting and preventing the harmful development of Candida albicans biofilms. We undertook a series of adsorption experiments with varying concentrations of curcumin, showing that 50 μg/ml could prevent adhesion. This effect could be further synergized by the curcumin pre-treatment of yeast cells to obtain significantly greater inhibition (>90%, p < 0.001. Investigation of the biological impact of curcumin showed that it preferentially affected immature morphological forms (yeast and germlings, and actively promoted aggregation of the cells. Transcriptional analyses showed that key adhesins were down-regulated (ALS1 and ALS3, whereas aggregation related genes (ALS5 and AAF1 were up-regulated. Collectively, these data demonstrated that curcumin elicits anti-adhesive effects and that induces transcription of genes integrally involved in the processes related to biofilm formation. Curcumin and associated polyphenols therefore have the capacity to be developed for use in oral healthcare to augment existing preventative strategies for candidal biofilms on the denture surface.

  8. Small but crucial: the novel small heat shock protein Hsp21 mediates stress adaptation and virulence in Candida albicans.

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    François L Mayer

    Full Text Available Small heat shock proteins (sHsps have multiple cellular functions. However, the biological function of sHsps in pathogenic microorganisms is largely unknown. In the present study we identified and characterized the novel sHsp Hsp21 of the human fungal pathogen Candida albicans. Using a reverse genetics approach we demonstrate the importance of Hsp21 for resistance of C. albicans to specific stresses, including thermal and oxidative stress. Furthermore, a hsp21Δ/Δ mutant was defective in invasive growth and formed significantly shorter filaments compared to the wild type under various filament-inducing conditions. Although adhesion to and invasion into human-derived endothelial and oral epithelial cells was unaltered, the hsp21Δ/Δ mutant exhibited a strongly reduced capacity to damage both cell lines. Furthermore, Hsp21 was required for resisting killing by human neutrophils. Measurements of intracellular levels of stress protective molecules demonstrated that Hsp21 is involved in both glycerol and glycogen regulation and plays a major role in trehalose homeostasis in response to elevated temperatures. Mutants defective in trehalose and, to a lesser extent, glycerol synthesis phenocopied HSP21 deletion in terms of increased susceptibility to environmental stress, strongly impaired capacity to damage epithelial cells and increased sensitivity to the killing activities of human primary neutrophils. Via systematic analysis of the three main C. albicans stress-responsive kinases (Mkc1, Cek1, Hog1 under a range of stressors, we demonstrate Hsp21-dependent phosphorylation of Cek1 in response to elevated temperatures. Finally, the hsp21Δ/Δ mutant displayed strongly attenuated virulence in two in vivo infection models. Taken together, Hsp21 mediates adaptation to specific stresses via fine-tuning homeostasis of compatible solutes and activation of the Cek1 pathway, and is crucial for multiple stages of C. albicans pathogenicity. Hsp21 therefore

  9. Adaptation of Candida albicans to environmental pH induces cell wall remodelling and enhances innate immune recognition.

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    Sarah L Sherrington

    2017-05-01

    Full Text Available Candida albicans is able to proliferate in environments that vary dramatically in ambient pH, a trait required for colonising niches such as the stomach, vaginal mucosal and the GI tract. Here we show that growth in acidic environments involves cell wall remodelling which results in enhanced chitin and β-glucan exposure at the cell wall periphery. Unmasking of the underlying immuno-stimulatory β-glucan in acidic environments enhanced innate immune recognition of C. albicans by macrophages and neutrophils, and induced a stronger proinflammatory cytokine response, driven through the C-type lectin-like receptor, Dectin-1. This enhanced inflammatory response resulted in significant recruitment of neutrophils in an intraperitoneal model of infection, a hallmark of symptomatic vaginal colonisation. Enhanced chitin exposure resulted from reduced expression of the cell wall chitinase Cht2, via a Bcr1-Rim101 dependent signalling cascade, while increased β-glucan exposure was regulated via a non-canonical signalling pathway. We propose that this "unmasking" of the cell wall may induce non-protective hyper activation of the immune system during growth in acidic niches, and may attribute to symptomatic vaginal infection.

  10. The effect of squalene on inflammation factors induced by candida albicans in vivo studies

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    Lee, Jun Haeng [Dept. of Radiology, Nambu University, Gwangju (Korea, Republic of)

    2016-09-15

    In the present study, whether squalene treatment relives inflammatory reactions induced by Candida albicans was checked. The experiment was conducted in vivo using seven experimental animals (ICR mice) per experimental group. Among C. albicans-induced inflammatory factors, TNF-α, IL-6, and NO were observed using the ELISA kits method. Through the experiment, the following conclusions were obtained. 1. In the group infected with C. albicans, it could be identified that squalene treatment was inducing NO generation in renal tissues both on the 1st and 3rd days (p < 0.05). 2. In the group pre-treated(intraperitoneal administration) with SQ (80ml/kg) once per day for seven days and infected with C. albicans, it could be identified that squalene treatment was inducing TNF-α generation in renal tissues only on the 3rd day(p < 0.05). 3. In the group pre-treated(intraperitoneal administration) with SQ (80ml/kg) once per day for seven days and infected with C. albicans, it could be identified that squalene treatment was inducing IL-6 generation in renal tissues only on the 3rd day(p < 0.05). In conclusion, it could be seen that for squalene to suppress C. albicans-induced inflammatory factors, preemptively supplying SQ should be effective. Therefore, effects for recovery from C. albicans-induced immunodepression can be expected from SQ treatment.

  11. Candida albicans Hom6 is a homoserine dehydrogenase involved in protein synthesis and cell adhesion

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    Pei-Wen Tsai

    2017-12-01

    Full Text Available Background/Purpose: Candida albicans is a common fungal pathogen in humans. In healthy individuals, C. albicans represents a harmless commensal organism, but infections can be life threatening in immunocompromised patients. The complete genome sequence of C. albicans is extremely useful for identifying genes that may be potential drug targets and important for pathogenic virulence. However, there are still many uncharacterized genes in the Candida genome database. In this study, we investigated C. albicans Hom6, the functions of which remain undetermined experimentally. Methods: HOM6-deleted and HOM6-reintegrated mutant strains were constructed. The mutant strains were compared with wild-type in their growth in various media and enzyme activity. Effects of HOM6 deletion on translation were further investigated by cell susceptibility to hygromycin B or cycloheximide, as well as by polysome profiling, and cell adhesion to polystyrene was also determined. Results: C. albicans Hom6 exhibits homoserine dehydrogenase activity and is involved in the biosynthesis of methionine and threonine. HOM6 deletion caused translational arrest in cells grown under amino acid starvation conditions. Additionally, Hom6 protein was found in both cytosolic and cell-wall fractions of cultured cells. Furthermore, HOM6 deletion reduced C. albicans cell adhesion to polystyrene, which is a common plastic used in many medical devices. Conclusion: Given that there is no Hom6 homologue in mammalian cells, our results provided an important foundation for future development of new antifungal drugs. Keywords: Candida albicans, cell adhesion, Hom6, homoserine dehydrogenase, protein synthesis

  12. Antifungal activity of Piper aduncum and Peperomia pellucida leaf ethanol extract against Candida albicans

    Science.gov (United States)

    Hastuti, Utami Sri; Ummah, Yunita Putri Irsadul; Khasanah, Henny Nurul

    2017-05-01

    This research was done to 1) examine the effect of Piper aduncum leaf ethanol extract at certain concentrations against Candida albicans colony growth inhibition in vitro; 2) examine the effect of Peperomia pellucida leaf ethanol extract at certain concentrations toward Candida albicans colony growth inhibition in vitro; and 3) determine the most effective concentration of P. aduncum and P. pellucida leaves ethanol extract against C. albicans colony growth inhibition in vitro. These plant extracts were prepared by the maceration technique using 95% ethanol, and then sterile filtered and evaporated to obtain the filtrate. The filtrate was diluted with sterile distilled water at certain concentrations, i.e.: 0%, 10%, 20%, 30%, 405, 50%, 60%, 70%, 80%, and 90%. The antifungal effect of each leaf extract concentration was examined by the agar diffusion method on Sabouraud Dextrose Agar medium. The research results are: 1) the P.aduncum leaf ethanol extract at some concentrations has an effect against C. albicans colony growth inhibition in vitro; 2) the P.pellucida leaf ethanol extract at some concentrations has an effect against C. albicans colony growth inhibition in vitro; 3) the P. aduncum leaf ethanol extract at 80% is the most effective for C. albicans colony growth inhibition in vitro; and 4) the P. pellucida leaf ethanol extract at 70% is the most effective for C. albicans colony growth inhibition in vitro.

  13. The effect of squalene on inflammation factors induced by candida albicans in vivo studies

    International Nuclear Information System (INIS)

    Lee, Jun Haeng

    2016-01-01

    In the present study, whether squalene treatment relives inflammatory reactions induced by Candida albicans was checked. The experiment was conducted in vivo using seven experimental animals (ICR mice) per experimental group. Among C. albicans-induced inflammatory factors, TNF-α, IL-6, and NO were observed using the ELISA kits method. Through the experiment, the following conclusions were obtained. 1. In the group infected with C. albicans, it could be identified that squalene treatment was inducing NO generation in renal tissues both on the 1st and 3rd days (p < 0.05). 2. In the group pre-treated(intraperitoneal administration) with SQ (80ml/kg) once per day for seven days and infected with C. albicans, it could be identified that squalene treatment was inducing TNF-α generation in renal tissues only on the 3rd day(p < 0.05). 3. In the group pre-treated(intraperitoneal administration) with SQ (80ml/kg) once per day for seven days and infected with C. albicans, it could be identified that squalene treatment was inducing IL-6 generation in renal tissues only on the 3rd day(p < 0.05). In conclusion, it could be seen that for squalene to suppress C. albicans-induced inflammatory factors, preemptively supplying SQ should be effective. Therefore, effects for recovery from C. albicans-induced immunodepression can be expected from SQ treatment

  14. Candida albicans infection in patients with oral squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Čanković Miloš

    2010-01-01

    Full Text Available Bacground/Aim. Systemic candidiasis in intensive care units remains an improtant problem due to antifungal resistance. Patients undergoing radiotherapy for head and neck cancer are at increased risk of developing oral candidiasis and they more frequent have prior fungi colonization. Due to identification of specific risk factors predisposing to fungal infection in order to threat such patients the aim of this study was to determine the presence of Candida species in patients with oral squamous cell carcinoma and compare it to the control subjects (patients with benign oral mucosal lesions. Methods. A total number of 30 consecutive oral cancer examined patients were included in this prospective study (24 men and 6 women with a mean age of 61.47 years, range 41-81 years. The control group consisted of 30 consecutive patients with histologically proven benign oral mucosal lesions (16 men and 14 women with a mean age of 54.53 years, range 16- 83 years. The samples for mycological examination were obtained by using sterile cotton swabs from the cancer lesion surface and in the patients of the control group from the benign mucosal lesion surface. Samples were inoculated in Sabouraud' dextrose agar. For identification purposes, Mackenzie germ tube test was performend on all isolates. Results. The prevalence of Candida was significantly higher in oral cancer patients than in control subjects (χ2 = 5.455, p = 0.020. Candida was found on nine of the 30 cancer surfaces; 5 (16.7% were identified as non-albicans Candida and 4 (13.3% as Candida albicans. In the control group, only Candida albicans was isolated from 2 (6.7% patients. In this study, no statistically significant differences in the presence of Candida species was found with respect to gender, age, smoking, alcohol consumption, wearing of dental protheses and the site of cancer lesion. Conclusion. The increased prevalence of yeasts on the surfaces of oral carcinoma indicates a need for their

  15. Paeonia lactiflora Inhibits Cell Wall Synthesis and Triggers Membrane Depolarization in Candida albicans.

    Science.gov (United States)

    Lee, Heung-Shick; Kim, Younhee

    2017-02-28

    Fungal cell walls and cell membranes are the main targets of antifungals. In this study, we report on the antifungal activity of an ethanol extract from Paeonia lactiflora against Candida albicans , showing that the antifungal activity is associated with the synergistic actions of preventing cell wall synthesis, enabling membrane depolarization, and compromising permeability. First, it was shown that the ethanol extract from P. lactiflora was involved in damaging the integrity of cell walls in C. albicans . In isotonic media, cell bursts of C. albicans by the P. lactiflora ethanol extract could be restored, and the minimum inhibitory concentration (MIC) of the P. lactiflora ethanol extract against C. albicans cells increased 4-fold. In addition, synthesis of (1,3)-β- D -glucan polymer was inhibited by 87% and 83% following treatment of C. albicans microsomes with the P. lactiflora ethanol extract at their 1× MIC and 2× MIC, respectively. Second, the ethanol extract from P. lactiflora influenced the function of C. albicans cell membranes. C. albicans cells treated with the P. lactiflora ethanol extract formed red aggregates by staining with a membrane-impermeable dye, propidium iodide. Membrane depolarization manifested as increased fluorescence intensity by staining P. lactiflora -treated C. albicans cells with a membrane-potential marker, DiBAC 4 (3) (( bis -1,3-dibutylbarbituric acid) trimethine oxonol). Membrane permeability was assessed by crystal violet assay, and C. albicans cells treated with the P. lactiflora ethanol extract exhibited significant uptake of crystal violet in a concentration-dependent manner. The findings suggest that P. lactiflora ethanol extract is a viable and effective candidate for the development of new antifungal agents to treat Candida -associated diseases.

  16. Inhibitory Effect of Alpha-Mangostin on Adhesion of Candida albicans to Denture Acrylic.

    Science.gov (United States)

    Kaomongkolgit, Ruchadaporn; Jamdee, Kusuma

    2015-01-01

    Candida-associated denture stomatitis is a very common disease affecting denture wearers. It is characterized by the presence of yeast biofilm on the denture, primarily associated with C. albicans. The investigation of agents that can reduce C. albicans adhesion may represent a significant advancement in the prevention and treatment of this disease. This study aims to investigate the effect of alpha-mangostin on the in vitro adhesion of C. albicans to denture acrylic and germ tube formation by C. albicans and to compare its activity with clotrimazole which is a topical antifungal agent commonly used for the treatment of Candida-associated denture stomatitis. Alpha-mangostin was extracted by thin layer chromatography. The effect of alpha-mangostin on adhesion of C. albicans to denture acrylic was determined by using a colorimetric tetrazolium assay and germ tube formation by C. albicans was determined by using the counting chamber. A significant reduction of C. albicans adhesion to denture acrylic was evident after exposure to 2,000 µg/ml of alpha-mangostin for only 15 min. In addition, the 2,000 µg/ml of the alpha-mangostin-treated C. albicans had a reduced ability for germ tube formation. These inhibitory effects of alpha-mangostin were as effective as clotrimazole. Alpha-mangostin has antifungal property against C. albicans by inhibiting the adhesion to denture acrylic and germ tube formation in vitro. These results suggest the potential application of alpha-mangostin as a topical medication or a natural oral hygiene product for treatment of Candida-associated denture stomatitis.

  17. Thymus vulgaris L. and thymol assist murine macrophages (RAW 264.7) in the control of in vitro infections by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans.

    Science.gov (United States)

    de Oliveira, Jonatas Rafael; Figueira, Leandro Wagner; Sper, Fábia Lugli; Meccatti, Vanessa Marques; Camargo, Samira Esteves Afonso; de Oliveira, Luciane Dias

    2017-08-01

    Microorganisms are capable to combat defense cells by means of strategies that contribute to their stabilization and proliferation in invaded tissues. Frequently antimicrobial-resistant strains appear; therefore, alternative methods to control them must be investigated, for example, the use of plant products. The capacity of the thyme extract (Thymus vulgaris L.) and phytocompound thymol in the control of in vitro infections by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in murine macrophages (RAW 264.7) was evaluated. Minimal inhibitory concentrations (MIC) of the plant products were used. The effect of these MIC were analyzed in the assays of phagocytosis and immunoregulation by analysis of the production of cytokines (IL-1β, TNF-α, and IL-10) and nitric oxide (NO). The plant products effectively assisted the macrophages in the phagocytosis of microorganisms, presenting significant reductions of S. aureus and P. aeruginosa. The macrophages also regulated the production of inflammatory mediators in the infections by S. aureus, P. aeruginosa, and C. albicans. In addition, thyme provided a satisfactory effect in response to the bacterial infections, regarding generation of NO. Thus, the effectiveness of the thyme and thymol to control in vitro infections by S. aureus, P. aeruginosa, and C. albicans was observed. Phagocytosis of S. aureus by RAW 264.7 was enhanced with thymol Thyme enhanced the phagocytosis of P. aeruginosa by RAW 264.7 Plant products provided immunoregulation of inflammatory cytokines Production of nitric oxide was improved with the treatments in bacterial infections.

  18. Catalytic isoforms Tpk1 and Tpk2 of Candida albicans PKA have non-redundant roles in stress response and glycogen storage.

    Science.gov (United States)

    Giacometti, Romina; Kronberg, Florencia; Biondi, Ricardo M; Passeron, Susana

    2009-05-01

    Candida albicans cAMP-dependent protein kinase (PKA) is coded by two catalytic subunits (TPK1 and TPK2) and one regulatory subunit (BCY1). In this organism the cAMP/PKA signalling pathway mediates basic cellular processes, such as the yeast-to-hyphae transition and cell cycle regulation. In the present study, we investigated the role of C. albicans PKA in response to saline, heat and oxidative stresses as well as in glycogen storage. To fine-tune the analysis, we performed the studies on several C. albicans PKA mutants having heterozygous or homozygous deletions of TPK1 and/or TPK2 in a different BCY1 genetic background. We observed that tpk1Delta/tpk1Delta strains developed a lower tolerance to saline exposure, heat shock and oxidative stress, while wild-type and tpk2Delta/tpk2Delta mutants were resistant to these stresses, indicating that both isoforms play different roles in the stress response pathway. We also found that regardless of the TPK background, heterozygous and homozygous BCY1 mutants were highly sensitive to heat treatment. Surprisingly, we observed that those strains devoid of one or both TPK1 alleles were defective in glycogen storage, while strains lacking Tpk2 accumulated higher levels of the polysaccharide, indicating that Tpk1 and Tpk2 have opposite roles in carbohydrate metabolism.

  19. Influence of radiation therapy on oral Candida albicans colonization: a quantitative assessment

    International Nuclear Information System (INIS)

    Rossie, K.M.; Taylor, J.; Beck, F.M.; Hodgson, S.E.; Blozis, G.G.

    1987-01-01

    An increase in quantity of oral Candida albicans was documented in patients receiving head and neck radiation therapy during and after therapy, as assessed by an oral-rinse culturing technique. The amount of the increase was greater in denture wearers and directly related to increasing radiation dose and increasing volume of parotid gland included in the radiation portal. A significant number of patients who did not carry C. albicans prior to radiation therapy developed positive cultures by 1 month after radiation therapy. The percentage of patients receiving head and neck radiation therapy who carried C. albicans prior to radiation therapy did not differ significantly from matched dental patient controls

  20. A 51Chromium release assay for phagocytic killing of Candida albicans

    International Nuclear Information System (INIS)

    Yamamura, M.; Boler, J.; Valdimarsson, H.

    1976-01-01

    Intracellular killing of Candida albicans was measured by a chromium release technique. Appropriate conditions were equal numbers of polymorphonuclear leucocytes (PMN) and 51 Chromium labelled C. albicans (10 6 /ml), fresh plasma at a final concentration of 2.5%, incubated at 37degC for 60 min. Using normal PMNs, 35-71% of releasable chromium was liberated into the supernatant under these conditions. This assay is easy to perform, requires a small amount of blood and offers an objective measurement of intracellular killing of C. albicans

  1. Adherence of Candida albicans to bladder mucosa: development and application of a tissue explant assay.

    Science.gov (United States)

    Lyman, C A; Navarro, E; Garrett, K F; Roberts, D D; Pizzo, P A; Walsh, T J

    1999-01-01

    In order to study the interactions between Candida species and uroepithelial tissue, a tissue explant assay was developed using bladder mucosa harvested from New Zealand white rabbits. Blastoconidia of Candida albicans, Candida tropicalis and Candida glabrata attached to the uroepithelial tissue in similar quantities. However, there was significantly more adherence to the uroepithelium by pre-germinated C. albicans compared with C. albicans blastoconidia. Furthermore, the amount of uroepithelial tissue injury was directly related to the length of exposure of the tissue to Candida. Thus, this tissue explant assay may provide a useful method for investigating properties related to fungal adherence to transitional uroepithelium and organism-mediated tissue injury.

  2. 17-β-Estradiol Upregulates the Stress Response in Candida albicans: Implications for Microbial Virulence

    OpenAIRE

    C. O’Connor; M. Essmann; B. Larsen

    1998-01-01

    Objective: The influence of 17-β-estradiol on the stress response of Candida albicans was studied.Methods: The survival of clinical isolates of C. albicans treated with 17-β-estradiol after heat and oxidative stress was measured by viable plate counts. Cellular proteins were analyzed via SDSPAGE.Results: The heat stress response induced by 17-β-estradiol in C. albicans grown at 25 ℃ protected the organisms against the lethal temperature of 48.5 ℃, as shown by viable plate counts. 17-β-estradi...

  3. 17-beta-estradiol upregulates the stress response in Candida albicans: implications for microbial virulence.

    OpenAIRE

    O'Connor, C; Essmann, M; Larsen, B

    1998-01-01

    OBJECTIVE: The influence of 17-beta-estradiol on the stress response of Candida albicans was studied. METHODS: The survival of clinical isolates of C. albicans treated with 17-beta-estradiol after heat and oxidative stress was measured by viable plate counts. Cellular proteins were analyzed via SDS-PAGE. RESULTS: The heat stress response induced by 17-beta-estradiol in C. albicans grown at 25 degrees C protected the organisms against the lethal temperature of 48.5 degrees C, as shown by viabl...

  4. Chromosome 1 trisomy compromises the virulence of Candida albicans.

    Science.gov (United States)

    Chen, Xi; Magee, B B; Dawson, Dean; Magee, P T; Kumamoto, Carol A

    2004-01-01

    Although increases in chromosome copy number typically have devastating developmental consequences in mammals, fungal cells such as Saccharomyces cerevisiae seem to tolerate trisomies without obvious impairment of growth. Here, we demonstrate that two commonly used laboratory strains of the yeast Candida albicans, CAI-4 and SGY-243, can carry three copies of chromosome 1. Although the trisomic strains grow well in the laboratory, Ura+ derivatives of CAI-4, carrying three copies of chromosome 1, are avirulent in the intravenously inoculated mouse model, unlike closely related strains carrying two copies of chromosome 1. Furthermore, changes in chromosome copy number occur during growth in an animal host and during growth in the presence of growth-inhibiting drugs. These results suggest that chromosome copy number variation provides a mechanism for genetic variation in this asexual organism.

  5. Identification of a Hydrophobin Gene That is Developmentally Regulated in the Ectomycorrhizal Fungus Tricholoma terreum

    OpenAIRE

    Mankel, Angela; Krause, Katrin; Kothe, Erika

    2002-01-01

    The symbiosis between ectomycorrhizal fungi and trees is an essential part of forest ecology and depends entirely on the communication between the two partners for establishing and maintaining the relationship. The identification and characterization of differentially expressed genes is a step to identifying such signals and to understanding the regulation of this process. We determined the role of hydrophobins produced by Tricholoma terreum in mycorrhiza formation and hyphal development. A h...

  6. In Vitro Effect of Local Anesthetics on Candida albicans Germ Tube Formation

    Directory of Open Access Journals (Sweden)

    Acácio Rodrigues

    1994-01-01

    Full Text Available Objective: This study was planned to clarify the in vitro effect of lidocaine and bupivacaine on germ tube formation by Candida albicans isolates from cases of clinical vaginal candidiasis.

  7. In Vitro Study on the Adhesion and Colonization of Candida Albicans on Metal and Acrylic Piercings

    Directory of Open Access Journals (Sweden)

    Stamenov N.

    2016-03-01

    Full Text Available Oral/perioral piercing may provide an ideal environment for adhesion and colonization of microorganisms. The aim of this study is to perform an “in vitro” research on the capabilities of adhesion of Candida albicans on oral piercings made of plastic and metal. Acrylic and metal piercings were incubated with Candida albicans and then were observed using scanning electron microscopy under different magnifications. A lot of irregularities and roughness were observed on the surface of the plastic piercing unlike the surface of the metal one, which is not so rough. Nevertheless, the number of Candida albicans colonies was considerably larger on the scanned metal surface in comparison to the plastic surface. In vitro the metal surface of the piercing creates better environment for the adhesion and colonization of microorganisms than the acrylic. This could be attributed to the electrostatic forces that most likely attract Candida albicans to the metal piercing in the early stages of biofilm formation.

  8. Impact of oxidative and osmotic stresses on Candida albicans biofilm formation.

    Science.gov (United States)

    Pemmaraju, Suma C; Padmapriya, Kumar; Pruthi, Parul A; Prasad, R; Pruthi, Vikas

    2016-09-01

    Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H2O2) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches.

  9. Biochemical characterization of recombinant dihydroorotate dehydrogenase from the opportunistic pathogenic yeast Candida albicans

    DEFF Research Database (Denmark)

    Zameitat, E.; Gojkovic, Zoran; Knecht, Wolfgang

    2006-01-01

    Candida albicans is the most prevalent yeast pathogen in humans, and recently it has become increasingly resistant to the current antifungal agents. In this study we investigated C. albicans dihydroorotate dehydrogenase (DHODH, EC 1.3.99.11), which catalyzes the fourth step of de novo pyrimidine...... lacks the targeting sequence and the transmembrane domain, were subcloned from C. albicans, recombinantly expressed in Escherichia coli, purified, and characterized for their kinetics and substrate specificity. An inhibitor screening with 28 selected compounds was performed. Only the dianisidine...... derivative, redoxal, and the biphenyl quinoline-carboxylic acid derivative, brequinar sodium, which are known to be potent inhibitors of mammalian DHODH, markedly reduced C. albicans DHODH activity. This study provides a background for the development of antipyrimidines with high efficacy for decreasing...

  10. Postantifungal effect of caspofungin against the Candida albicans and Candida parapsilosis clades.

    Science.gov (United States)

    Gil-Alonso, Sandra; Jauregizar, Nerea; Eraso, Elena; Quindós, Guillermo

    2016-10-01

    Killing and postantifungal effects could be relevant for the selection of optimal dosing schedules. This study aims to compare time-kill and postantifungal effects with caspofungin on Candida albicans (C. albicans, Candida dubliniensis, Candida africana) and Candida parapsilosis (C. parapsilosis, Candida metapsilosis, Candida orthopsilosis) clades. In the postantifungal effect experiments, strains were exposed to caspofungin for 1 h at concentrations 0.12-8 μg/mL. Time-kill experiments were conducted at the same concentrations. Caspofungin exhibited a significant and prolonged postantifungal effect (>37 h) with 2 μg/mL against the most strains of C. albicans clade. Against the C. parapsilosis clade, the postantifungal effect was albicans, C. dubliniensis and C. metapsilosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Curcumin uptake enhancement using low dose light illumination during incubation in Candida albicans

    Science.gov (United States)

    Romano, Renan A.; Pratavieira, Sebastião.; da Silva, Ana P.; Kurachi, Cristina; Bagnato, Vanderlei S.; Guimarães, Francisco E. G.

    2017-07-01

    A new PDI protocol is presented in this study. C. albicans cells pre-illuminated with a low dose light demonstrated an increase of curcumin uptake when compared to dark incubation, leading to a higher PDI efficacy.

  12. DAYA ANTIFUNGAL DEKOK KAYU MANIS (Cinnamomum burmanni TERHADAP Candida Albicans SECARA IN VITRO

    Directory of Open Access Journals (Sweden)

    Lailia Nur Rachma

    2012-09-01

    Full Text Available Candida albicans is the most oportunis fungi that cause flour albus. Cinnamomum burmanni have been widely known as therapy for flour albus. This efect caused by its chemical compound such as cinnamaldehyde, eugenol, cinnamic acid, limonene, cathecin, coumarin, linalool, and tannin. This research aims was to know the comparison of antifungal potency of Cinnamomum burmanni on Candida albicans in vitro. The design was true experimental. The decoction concentrations of Cinnamomum burmanni that were used were 8%, 4%, 2%, 1%, 0.5%, 0.25%, and 0.125% with three time repetition. The data was analized with One-way ANOVA test with convidence interval 95% (p < 0.05. One-way ANOVA test gave result Cinnamomum burmanni had antifungal potency against Candida albicans. Minimum Inhibitory Concentration (MIC of Cinnamomum burmanni was 1%. Minimum Fungicidal Concentration (MFC of Cinnamomum burmanni was 2%. The conclusion was Cinnamomum burmanni had antifungal potency against Candida albicans in vitro.

  13. Manipulation of Host Diet To Reduce Gastrointestinal Colonization by the Opportunistic Pathogen Candida albicans.

    Science.gov (United States)

    Gunsalus, Kearney T W; Tornberg-Belanger, Stephanie N; Matthan, Nirupa R; Lichtenstein, Alice H; Kumamoto, Carol A

    2016-01-01

    Candida albicans, the most common human fungal pathogen, can cause systemic infections with a mortality rate of ~40%. Infections arise from colonization of the gastrointestinal (GI) tract, where C. albicans is part of the normal microflora. Reducing colonization in at-risk patients using antifungal drugs prevents C. albicans-associated mortalities. C. albicans provides a clinically relevant system for studying the relationship between diet and the microbiota as it relates to commensalism and pathogenicity. As a first step toward a dietary intervention to reduce C. albicans GI colonization, we investigated the impact of dietary lipids on murine colonization by C. albicans. Coconut oil and its constituent fatty acids have antifungal activity in vitro; we hypothesized that dietary coconut oil would reduce GI colonization by C. albicans. Colonization was lower in mice fed a coconut oil-rich diet than in mice fed diets rich in beef tallow or soybean oil. Switching beef tallow-fed mice to a coconut oil diet reduced preexisting colonization. Coconut oil reduced colonization even when the diet also contained beef tallow. Dietary coconut oil also altered the metabolic program of colonizing C. albicans cells. Long-chain fatty acids were less abundant in the cecal contents of coconut oil-fed mice than in the cecal contents of beef tallow-fed mice; the expression of genes involved in fatty acid utilization was lower in C. albicans from coconut oil-fed mice than in C. albicans from beef tallow-fed mice. Extrapolating to humans, these findings suggest that coconut oil could become the first dietary intervention to reduce C. albicans GI colonization. IMPORTANCE Candida albicans, the most common human fungal pathogen, can cause infections with a mortality rate of ~40%. C. albicans is part of the normal gut flora, but when a patient's immune system is compromised, it can leave the gut and cause infections. By reducing the amount of C. albicans in the gut of susceptible

  14. Rare presentation of Candida albicans: infective endocarditis and a pulmonary coin lesion.

    Science.gov (United States)

    Öner, Taliha; Korun, Oktay; Çelebi, Ahmet

    2018-04-01

    We present a case of a rare association of infective endocarditis and a coin lesion in the lung caused by Candida albicans. The lesion disappeared after 6 weeks of treatment with 5 mg/kg/day amphotericin B.

  15. Functional genomics identifies type I interferon pathway as central for host defense against Candida albicans

    NARCIS (Netherlands)

    Smeekens, Sanne P.; Ng, Aylwin; Kumar, Vinod; Johnson, Melissa D.; Plantinga, Theo S.; van Diemen, Cleo; Arts, Peer; Verwiel, Eugene T. P.; Gresnigt, Mark S.; Fransen, Karin; van Sommeren, Suzanne; Oosting, Marije; Cheng, Shih-Chin; Joosten, Leo A. B.; Hoischen, Alexander; Kullberg, Bart-Jan; Scott, William K.; Perfect, John R.; van der Meer, Jos W. M.; Wijmenga, Cisca; Netea, Mihai G.; Xavier, Ramnik J.

    Candida albicans is the most common human fungal pathogen causing mucosal and systemic infections. However, human antifungal immunity remains poorly defined. Here by integrating transcriptional analysis and functional genomics, we identified Candida-specific host defence mechanisms in humans.

  16. Phenotypic aspects of oral strains of Candida albicans in children with down's syndrome

    Directory of Open Access Journals (Sweden)

    E. L. Ribeiro

    Full Text Available The aim of this article is to characterize the biological aspects of oral strains of C. albicans in children with Down's syndrome. These yeasts were analyzed as to their macromorphological and enzymatic aspects and were tested as to their in vitro susceptibility to antifungal drugs using broth microdilution to determine the minimum inhibitory concentration (MIC. The morphotyping revealed that all oral C. albicans isolates from children with Down's syndrome promoted the formation of fringes regardless of size, while the control group presented smaller fringes. All oral C. albicans strains produced proteinase, but those with phospholipolytic activity showed greater enzyme capacity in the test group. In vitro susceptibility showed that all oral C. albicans isolates were sensitive to the drugs used.

  17. Rad51-Rad52 mediated maintenance of centromeric chromatin in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Sreyoshi Mitra

    2014-04-01

    Full Text Available Specification of the centromere location in most eukaryotes is not solely dependent on the DNA sequence. However, the non-genetic determinants of centromere identity are not clearly defined. While multiple mechanisms, individually or in concert, may specify centromeres epigenetically, most studies in this area are focused on a universal factor, a centromere-specific histone H3 variant CENP-A, often considered as the epigenetic determinant of centromere identity. In spite of variable timing of its loading at centromeres across species, a replication coupled early S phase deposition of CENP-A is found in most yeast centromeres. Centromeres are the earliest replicating chromosomal regions in a pathogenic budding yeast Candida albicans. Using a 2-dimensional agarose gel electrophoresis assay, we identify replication origins (ORI7-LI and ORI7-RI proximal to an early replicating centromere (CEN7 in C. albicans. We show that the replication forks stall at CEN7 in a kinetochore dependent manner and fork stalling is reduced in the absence of the homologous recombination (HR proteins Rad51 and Rad52. Deletion of ORI7-RI causes a significant reduction in the stalled fork signal and an increased loss rate of the altered chromosome 7. The HR proteins, Rad51 and Rad52, have been shown to play a role in fork restart. Confocal microscopy shows declustered kinetochores in rad51 and rad52 mutants, which are evidence of kinetochore disintegrity. CENP-ACaCse4 levels at centromeres, as determined by chromatin immunoprecipitation (ChIP experiments, are reduced in absence of Rad51/Rad52 resulting in disruption of the kinetochore structure. Moreover, western blot analysis reveals that delocalized CENP-A molecules in HR mutants degrade in a similar fashion as in other kinetochore mutants described before. Finally, co-immunoprecipitation assays indicate that Rad51 and Rad52 physically interact with CENP-ACaCse4 in vivo. Thus, the HR proteins Rad51 and Rad52

  18. Crystal structure of the WOPR-DNA complex and implications for Wor1 function in white-opaque switching of Candida albicans.

    Science.gov (United States)

    Zhang, Shicheng; Zhang, Tianlong; Yan, Minghui; Ding, Jianping; Chen, Jiangye

    2014-09-01

    Wor1 (white-opaque switching regulator 1) is a master regulator of the white-opaque switching in Candida albicans, an opportunistic human fungal pathogen, and is associated with its pathogenicity and commensality. Wor1 contains a conserved DNA-binding region at the N-terminus, consisting of two conserved segments (WOPRa and WOPRb) connected by a non-conserved linker that can bind to specific DNA sequences of the promoter regions and then regulates the transcription. Here, we report the crystal structure of the C. albicans Wor1 WOPR segments in complex with a double-stranded DNA corresponding to one promoter region of WOR1. The sequentially separated WOPRa and WOPRb are structurally interwound together to form a compact globular domain that we term the WOPR domain. The WOPR domain represents a new conserved fungal-specific DNA-binding domain which uses primarily a conserved loop to recognize and interact specifically with a conserved 6-bp motif of the DNA in both minor and major grooves. The protein-DNA interactions are essential for WOR1 transcriptional regulation and white-to-opaque switching. The structural and biological data together reveal the molecular basis for the recognition and binding specificity of the WOPR domain with its specific DNA sequences and the function of Wor1 in the activation of transcription.

  19. Genome-wide gene expression profiling and a forward genetic screen show that differential expression of the sodium ion transporter Ena21 contributes to the differential tolerance of Candida albicans and Candida dubliniensis to osmotic stress.

    LENUS (Irish Health Repository)

    Enjalbert, Brice

    2009-04-01

    Candida albicans is more pathogenic than Candida dubliniensis. However, this disparity in virulence is surprising given the high level of sequence conservation and the wide range of phenotypic traits shared by these two species. Increased sensitivity to environmental stresses has been suggested to be a possible contributory factor to the lower virulence of C. dubliniensis. In this study, we investigated, in the first comparison of C. albicans and C. dubliniensis by transcriptional profiling, global gene expression in each species when grown under conditions in which the two species exhibit differential stress tolerance. The profiles revealed similar core responses to stresses in both species, but differences in the amplitude of the general transcriptional responses to thermal, salt and oxidative stress. Differences in the regulation of specific stress genes were observed between the two species. In particular, ENA21, encoding a sodium ion transporter, was strongly induced in C. albicans but not in C. dubliniensis. In addition, ENA21 was identified in a forward genetic screen for C. albicans genomic sequences that increase salt tolerance in C. dubliniensis. Introduction of a single copy of CaENA21 was subsequently shown to be sufficient to confer salt tolerance upon C. dubliniensis.

  20. A virtual infection model quantifies innate effector mechanisms and Candida albicans immune escape in human blood.

    Directory of Open Access Journals (Sweden)

    Kerstin Hünniger

    2014-02-01

    Full Text Available Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost [Formula: see text] of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment

  1. Antimicrobial effects of Coleus amboinicus, Lour folium infusum towards Candida albicans and Streptococcus mutans

    OpenAIRE

    Rianti, Devi; Yogyarti, Sri

    2006-01-01

    A laboratory experimental study conducted on antimicrobial effects of Coleus amboinicus, Lour folium Infusum towards Candida albicans and Streptococcus mutans (S. mutans). Effective concentration of Coleus amboinicus, Lour to decrease the quantities Candida albicans and S. mutans colonies is expected to be found out in this study. This study was using Coleus Amboinicus, Lour folium infusum with 12.5%, 15%, 17.5%, 20%, and 22.5% concentrations. Sterilized aquadest used as a control. Candida al...

  2. A Virtual Infection Model Quantifies Innate Effector Mechanisms and Candida albicans Immune Escape in Human Blood

    Science.gov (United States)

    Bieber, Kristin; Martin, Ronny; Figge, Marc Thilo; Kurzai, Oliver

    2014-01-01

    Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment–model–experiment cycles allowed

  3. Comparison of dielectric barrier discharge modes fungicidal effect on candida albicans growth

    International Nuclear Information System (INIS)

    Slama, J.; Kriha, V.; Fantova, V.; Julak, J.

    2013-01-01

    Filamentary and quasi-homogeneous mode of dielectric barrier discharge (DBD) was investigated as a plasma source with fungicidal effect on Candida albicans yeast inoculated on Sabouraud agar wafers. As compared with the filamentary DBD mode, the quasi-homogeneous mode had significantly better results: shorter exposition time needed for inhibiting C. albicans yeast, moreover the quasi-homogeneous mode had gentle influence on the agar surface structure.

  4. Influence of Candida krusei and Candida glabrata on Candida albicans gene expression in in vitro biofilms.

    Science.gov (United States)

    Barros, Patrícia Pimentel; Ribeiro, Felipe Camargo; Rossoni, Rodnei Dennis; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

    2016-04-01

    The present study aimed to evaluate the interactions between the species Candida albicans, Candida krusei and Candida glabrata in monotypic and mixed biofilm models formed in vitro as well as the relative expression of the ALS1, ALS3, HWP1, BCR1, EFG1, TEC1, SAP5, PLB2 and LIP9 genes. Mixed (C. albicans/C. krusei and C. albicans/C. glabrata) and monotypic biofilms were cultured for 0, 12 and 24h. Gene expression was analyzed in the same biofilm model in which the number of CFU/mL was counted. The C. albicans CFU/mL values were lower at the 12 and 24h time points in the mixed biofilms compared with the monotypic biofilms, and decreases of 56.23% and 64.4% in C. albicans were observed when this species was associated with C. glabrata and C. krusei, respectively. In the presence of C. krusei, the expression of the ALS3, HWP1, BCR1, EFG1 and TEC1 genes of C. albicans was completely inhibited, indicating both transcriptome and the phenotypic antagonism between these two species, but genes related to the secretion of enzymes were stimulated. In the presence of C. glabrata, C. albicans showed a similar gene expression profile to that obtained in association with C. krusei, though it was altered to a lesser degree. We conclude that C. krusei and C. glabrata may alter or inhibit the mechanisms involved in the in vitro adherence and formation of C. albicans biofilms, influencing the pathogenicity of this species and suggesting a competitive interaction with C. krusei and C. glabrata in biofilm formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Oral Immunization Against Candidiasis Using Lactobacillus casei Displaying Enolase 1 from Candida albicans

    OpenAIRE

    Shibasaki, Seiji; Karasaki, Miki; Tafuku, Senji; Aoki, Wataru; Sewaki, Tomomitsu; Ueda, Mitsuyoshi

    2014-01-01

    Abstract Candidiasis is a common fungal infection that is prevalent in immunocompromised individuals. In this study, an oral vaccine against Candida albicans was developed by using the molecular display approach. Enolase 1 protein (Eno1p) of C. albicans was expressed on the Lactobacillus casei cell surface by using poly-gamma-glutamic acid synthetase complex A from Bacillus subtilis as an anchoring protein. The Eno1p-displaying L. casei cells were used to immunize mice, which were later chall...

  6. Adding Biotin to Parenteral Nutrition Solutions Without Lipid Accelerates the Growth of Candida albicans

    Science.gov (United States)

    Kuwahara, Takashi; Kaneda, Shinya; Shimono, Kazuyuki

    2016-01-01

    Background: We have previously demonstrated that Candida albicans requires multivitamins (MVs) or lipid to increase rapidly in parenteral nutrition (PN) solutions. In this study, in detail, the effects of vitamins on the growth of C. albicans in PN solutions without lipid were investigated. Methods: In the 1st experiment, a commercial PN solution without lipid was supplemented with water-soluble vitamins (SVs: vitamins B1, B2, B6, B12 and C, folic acid, nicotinamide, biotin and panthenol), water-insoluble vitamins (IVs: vitamins A, D, E and K) or both (MVs). In the 2nd experiment, the test solutions were prepared by supplementing the PN solution with one of each or all of the SVs. In the 3rd experiment, another commercial peripheral PN (PPN) solution without lipid was supplemented with SVs, nicotinic acid, biotin or both nicotinic acid and biotin. In each of the experiments, a specified number of C. albicans organisms was added to each test solution, and all of the test solutions were allowed to stand at room temperature (23-26ºC). The number of C. albicans was counted at 0, 24, 48 and 72 hours after the addition of the organism. Results: In the 1st experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs, but increased slowly without the SVs, regardless of the addition of the IVs. In the 2nd experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs or biotin, but increased slowly with each of the other water-soluble vitamins. In the 3rd experiment, the C. albicans increased rapidly in the PPN solution supplemented with the SVs or biotin, but increased slowly with the addition of nicotinic acid. Conclusions: These results suggested that adding MVs or SVs to PN solutions without lipid promotes the growth of C. albicans, and that this effect is mostly attributable to biotin. PMID:27648003

  7. Quantification and Optimization of Candida albicans DNA in Blood Samples Using Real- Time PCR

    Directory of Open Access Journals (Sweden)

    Mojtaba Nabili

    2013-10-01

    Full Text Available Background: Candida albicans (C. albicans is a major cause of candidaemia in people with impaired immunity. Blood culture is a “gold standard” for candidaemia detection but is time-consuming and relatively insensitive. We established a real-time PCR assay for C. albicans detection in blood by LightCycler PCR and melting curve analysis. Methods: Five milliliter blood samples from healthy volunteers were spiked with 100-106 C. albicans cells to determine the detection limit of our method. DNA was extracted from whole blood using glass beads and the QIAamp DNA Blood Mini Kit (Qiagen, Hilden Germany. DNA from C. albicans isolates were amplified with primers and inserted into Escherichia coli (E. coli DH5α.1 cells with the TA cloning vector (Invitrogen. The plasmid was used for standardization and optimization. A quantitative PCR assay with the LightCycler amplification and d