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Nickerson KW, Gutzmann DJ, Boone CHT, Pathirana RU, Atkin AL. Physiological adventures in Candida albicans: farnesol and ubiquinones. Microbiol Mol Biol Rev 2024; 88:e0008122. [PMID: 38436263 PMCID: PMC10966945 DOI: 10.1128/mmbr.00081-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
SUMMARYFarnesol was first identified as a quorum-sensing molecule, which blocked the yeast to hyphal transition in Candida albicans, 22 years ago. However, its interactions with Candida biology are surprisingly complex. Exogenous (secreted or supplied) farnesol can also act as a virulence factor during pathogenesis and as a fungicidal agent triggering apoptosis in other competing fungi. Farnesol synthesis is turned off both during anaerobic growth and in opaque cells. Distinctly different cellular responses are observed as exogenous farnesol levels are increased from 0.1 to 100 µM. Reported changes include altered morphology, stress response, pathogenicity, antibiotic sensitivity/resistance, and even cell lysis. Throughout, there has been a dearth of mechanisms associated with these observations, in part due to the absence of accurate measurement of intracellular farnesol levels (Fi). This obstacle has recently been overcome, and the above phenomena can now be viewed in terms of changing Fi levels and the percentage of farnesol secreted. Critically, two aspects of isoprenoid metabolism present in higher organisms are absent in C. albicans and likely in other yeasts. These are pathways for farnesol salvage (converting farnesol to farnesyl pyrophosphate) and farnesylcysteine cleavage, a necessary step in the turnover of farnesylated proteins. Together, these developments suggest a unifying model, whereby high, threshold levels of Fi regulate which target proteins are farnesylated or the extent to which they are farnesylated. Thus, we suggest that the diversity of cellular responses to farnesol reflects the diversity of the proteins that are or are not farnesylated.
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Affiliation(s)
| | - Daniel J. Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Cory H. T. Boone
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Ruvini U. Pathirana
- Department of Biology and Chemistry, Texas A&M International University, Laredo, Texas, USA
| | - Audrey L. Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
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Koide T, Tamura M. Effect of diglyceryl dicaprylate on Candida albicans growth and pathogenicity. Biosci Biotechnol Biochem 2021; 85:2334-2342. [PMID: 34508624 DOI: 10.1093/bbb/zbab159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/07/2021] [Indexed: 01/06/2023]
Abstract
The antifungal effect of diglyceryl dicaprylate, one of the emulsifiers used as a food additive, on Candida albicans that is a pathogenic fungus that is predominant in the oral cavity was investigated. This component did not affect C. albicans growth; however, it suppressed some virulence factors in a concentration-dependent manner. Furthermore, the suppression of pathogenic factors, such as biofilm formation, adhesion, highly pathogenic dimorphism, and ability to produce proteolytic enzymes, was due to reduction in mRNA expression levels of genes involved in fungal pathogenicities. From these results, this emulsifier could potentially prevent the development of intraoral and extraoral diseases involving C. albicans and could potentially use in oral care and improvement of quality of life.
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Affiliation(s)
- Tomojiro Koide
- Department of Food Ingredients Development, Riken Vitamin Co., Ltd., Mihama-ku Chiba-City, Chiba, Japan
| | - Muneaki Tamura
- Department of Microbiology, Nihon University School of Dentistry, Kanda-surugadai Chiyoda-ku, Tokyo, Japan
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3
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Saville SP, Cleary IA. Geldanamycin-Induced Morphological Changes Require Candida albicans Hyphal Growth Regulatory Machinery. Mycopathologia 2021; 186:103-107. [PMID: 33389485 DOI: 10.1007/s11046-020-00511-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 11/19/2020] [Indexed: 11/26/2022]
Abstract
In Candida albicans, geldanamycin treatment inhibits the essential chaperone Hsp90 and induces a change from yeast to filamentous morphology, likely by impeding cell cycle progression and division. However, filaments formed by wild-type cells upon geldanamycin exposure are quite different in appearance from true hyphae. We have observed that effects on morphology caused by geldanamycin treatment appear to vary in strains with defects in different morphological regulators. These results indicate that the filamentous forms induced by inhibiting Hsp90p, while not true hyphae, nonetheless require some components of the hypha induction machinery for their formation. Furthermore, we have found that BRG1, a known regulator of hypha formation, is also required for pseudohypha induction in response to nitrogen starvation and for the formation of elongated filaments upon exposure to geldanamycin.
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Affiliation(s)
- Stephen P Saville
- Department of Biology, The South Texas Center for Emerging Infectious Diseases, The University of Texas At San Antonio, San Antonio, TX, USA
| | - Ian A Cleary
- Department of Biomedical Sciences, Grand Valley State University, One Campus Drive, Allendale, MI, 49401, USA.
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4
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Le PH, Nguyen DHK, Aburto-Medina A, Linklater DP, Crawford RJ, MacLaughlin S, Ivanova EP. Nanoscale Surface Roughness Influences Candida albicans Biofilm Formation. ACS APPLIED BIO MATERIALS 2020; 3:8581-8591. [PMID: 35019629 DOI: 10.1021/acsabm.0c00985] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The microbial contamination of surfaces presents a significant challenge due to the adverse effects associated with biofilm formation, particularly on implantable devices. Here, the attachment and biofilm formation of the opportunistic human pathogen, Candida albicans ATCC 10231, were studied on surfaces with decreasing magnitudes of nanoscale roughness. The nanoscale surface roughness of nonpolished titanium, polished titanium, and glass was characterized according to average surface roughness, skewness, and kurtosis. Nonpolished titanium, polished titanium, and glass possessed average surface roughness (Sa) values of 350, 20, and 2.5 nm; skewness (Sskw) values of 1.0, 4.0, and 1.0; and (Skur) values of 3.5, 16, and 4, respectively. These unique characteristics of the surface nanoarchitecture were found to play a key role in limiting C. albicans attachment and modulating the functional phenotypic changes associated with biofilm formation. Our results suggest that surfaces with a specific combination of surface topographical parameters could prevent the attachment and biofilm formation of C. albicans. After 7 days, the density of attached C. albicans cells was recorded to be 230, 70, and 220 cells mm-2 on nonpolished titanium, polished titanium, and glass surfaces, respectively. Despite achieving a very low attachment density, C. albicanscells were only observed to produce hyphae associated with biofilm formation on nonpolished titanium surfaces, possessing the highest degree of surface roughness (Sa = 350 nm). This study provides a more comprehensive picture of the impact of surface architectures on C. albicans attachment, which is beneficial for the design of antifungal surfaces.
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Affiliation(s)
- Phuc H Le
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia.,Australian Research Council Research Hub for Australian Steel Manufacturing, Wollongong, New South Wales 2500, Australia
| | - Duy H K Nguyen
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia
| | - Arturo Aburto-Medina
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia.,Australian Research Council Research Hub for Australian Steel Manufacturing, Wollongong, New South Wales 2500, Australia
| | - Denver P Linklater
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia
| | - Russell J Crawford
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia
| | | | - Elena P Ivanova
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Victoria 3000, Australia
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5
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Nomura T, Murakami T, Shimoyama Y, Kobayashi T, Furuya J, Sasaki M, Kondo H. Effects of denture adhesives on growth and morphological transformation of Candida albicans. J Prosthodont Res 2020; 64:78-84. [DOI: 10.1016/j.jpor.2019.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 02/28/2019] [Accepted: 04/11/2019] [Indexed: 10/26/2022]
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Ikezaki S, Cho T, Nagao JI, Tasaki S, Yamaguchi M, Arita-Morioka KI, Yasumatsu K, Chibana H, Ikebe T, Tanaka Y. Mild Heat Stress Affects on the Cell Wall Structure in Candida albicans Biofilm. Med Mycol J 2019; 60:29-37. [PMID: 31155569 DOI: 10.3314/mmj.19-00001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We previously reported that Candida albicans responded to mild heat stress in a range of temperature elevations simulating fever, and concluded that mild heat stress increases susceptibility to antifungal drugs. In this study, we show that mild heat stress causes a morphological change in hyphae during the process of biofilm formation. We found that mild heat stress extended the period of hyphal stage maintenance in C. albicans biofilm. Although the rate of hyphal change from yeast form to hyphal form reached the maximum within 3 hr, later, almost every cell quickly reverted to the yeast growth phase within 6 hr at 37°C but not at 39°C, or under mild heat stress. Electron microscopy using a smart specimen preparation technique revealed that mild heat stress significantly increased the thickness of the inner cell wall accompanied by a decrease in density of the outer cell wall in the hyphae of C. albicans biofilm. To identify the gene responsible for the morphological changes associated with mild heat stress, we performed microarray gene expression analysis. Eleven genes were upregulated and 17 genes were downregulated under mild heat stress in biofilm cells. The increased PHR1 gene expression in response to mild heat stress was confirmed in quantitative RT-PCR analysis. The mutant upregulated PHR1 expression showed the same sensitivity against antifungal drug micafungin as dependent on mild heat stress. Our findings point to possible therapeutic effects of hyperthermia as well as to the effect of fever during infections.
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Affiliation(s)
- Shojiro Ikezaki
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College.,Section of Oral Surgery, Department of Oral and Maxillofacial Surgery, Fukuoka Dental College
| | - Tamaki Cho
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College
| | - Jun-Ichi Nagao
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College
| | - Sonoko Tasaki
- Section of Dentistry for the Disabled, Department of Oral Growth and Development, Fukuoka Dental College
| | | | - Ken-Ichi Arita-Morioka
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College
| | - Kanae Yasumatsu
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College
| | | | - Tetsuro Ikebe
- Section of Oral Surgery, Department of Oral and Maxillofacial Surgery, Fukuoka Dental College
| | - Yoshihiko Tanaka
- Section of Infection Biology, Department of Functional Bioscience, Fukuoka Dental College
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Yang W, Zhou Y, Wu C, Tang J. Enterohemorrhagic Escherichia coli promotes the invasion and tissue damage of enterocytes infected with Candida albicans in vitro. Sci Rep 2016; 6:37485. [PMID: 27874093 PMCID: PMC5118719 DOI: 10.1038/srep37485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 10/31/2016] [Indexed: 12/26/2022] Open
Abstract
The principal aim of this study was to investigate the in vitro co-infection of Caco-2 cells with Candida albicans and enterohemorrhage Escherichia coli (EHEC). The ability of both species to colonize or invade the Caco-2 cells was evaluated by indirect immunofluorescence and inverted microscopy. The damage to Caco-2 cells was evaluated by measuring lactate dehydrogenase (LDH) activity. C. albicans virulence gene expression (HWP1, ALS3, PLB1, SAP4, and EFG1) was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Compared to single infections with enterohemorrhage Escherichia coli or C. albicans, a co-infection colonized or invaded Caco-2 cells more quickly, and C. albicans tended to accumulate more easily, accompanied by the upregulation of related genes. In addition, the LDH activity in the co-infected group was higher than in cells infected with C. albicans or with enterohemorrhage Escherichia coli, accompanied by the upregulation of toxicity-related genes. Using Caco-2 cells as an infection model, this study demonstrated that co-infecting in vitro enterocytes with C. albicans and enterohemorrhage Escherichia coli enhanced the invasiveness and tissue damaging effects of C. albicans.
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Affiliation(s)
- Weiming Yang
- Department of Trauma-Emergency &Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, P.R. China
| | - Yanjun Zhou
- Division of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R. China
| | - Chunrong Wu
- Department of Trauma-Emergency &Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, P.R. China
| | - Jianguo Tang
- Department of Trauma-Emergency &Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, P.R. China
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8
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Cleary IA, Reinhard SM, Lazzell AL, Monteagudo C, Thomas DP, Lopez-Ribot JL, Saville SP. Examination of the pathogenic potential of Candida albicans filamentous cells in an animal model of haematogenously disseminated candidiasis. FEMS Yeast Res 2016; 16:fow011. [PMID: 26851404 DOI: 10.1093/femsyr/fow011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2016] [Indexed: 11/12/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans is an increasingly common threat to human health. Candida albicans grows in several morphologies and mutant strains locked in yeast or filamentous forms have attenuated virulence in the murine model of disseminated candidiasis. Thus, the ability to change shape is important for virulence. The transcriptional repressors Nrg1p and Tup1p are required for normal regulation of C. albicans morphology. Strains lacking either NRG1 or TUP1 are constitutively pseudohyphal under yeast growth conditions, and display attenuated virulence in the disseminated model. To dissect the relative importance of hyphae and pseudohyphae during an infection, we used strains in which the morphological transition could be externally manipulated through controlled expression of NRG1 or TUP1. Remarkably, hyphal form inocula retain the capacity to cause disease. Whilst induction of a pseudohyphal morphology through depletion of TUP1 did result in attenuated virulence, this was not due to a defect in the ability to escape the bloodstream. Instead, we observed that pseudohyphal cells are cleared from tissues much more efficiently than either hyphal (virulent) or yeast form (avirulent) cells, indicating that different C. albicans morphologies have distinct interactions with host cells during an infection.
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Affiliation(s)
- Ian A Cleary
- Department of Biological Sciences, The University of Tennessee at Martin, Martin, TN 38238, USA
| | - Sara M Reinhard
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Anna L Lazzell
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Carlos Monteagudo
- Departamento de Patologia, Facultad de Medicina y Odontologia, Universidad de Valencia, Avda. Blasco Ibañez, 17, 46010 Valencia, España
| | - Derek P Thomas
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI 49401, USA
| | - Jose L Lopez-Ribot
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Stephen P Saville
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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Saito H, Tamura M, Imai K, Ishigami T, Ochiai K. Catechin inhibits Candida albicans dimorphism by disrupting Cek1 phosphorylation and cAMP synthesis. Microb Pathog 2013; 56:16-20. [PMID: 23337884 DOI: 10.1016/j.micpath.2013.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/06/2012] [Accepted: 01/10/2013] [Indexed: 11/17/2022]
Abstract
Candida albicans is a fungal pathogen that undergoes dimorphism (transformation from a yeast form to a hyphal form), wherein, the yeast form is identified as a disseminating form that plays a critical role in the early stages of Candida disease progression, while the hyphal form is found to exert additional pathogenicity by adapting to various environmental conditions. Here, we elucidated the effects of catechin on C. albicans hyphal formation. Flow cytometry analysis showed catechin inhibited FCS-induced hyphal formation. Moreover, hypha-specific gene expression in MAP kinase cascade and cAMP pathway was decreased ascribable to catechin. Furthermore, through Western blotting and cAMP synthesis analysis, we found catechin obstructs Cek1 phosphorylation in MAP kinase cascade and suppresses cAMP synthesis. These results suggest that catechin possesses anti-dimorphism activity by interfering with in vitro signal transduction. Similarly, this highlights the possible application of catechin in clinical therapy for the management and prevention of candidosis.
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Affiliation(s)
- Hideo Saito
- Department of Partial Denture Prosthodontics, Nihon University School of Dentistry, Japan
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10
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Nagao JI, Cho T, Uno J, Ueno K, Imayoshi R, Nakayama H, Chibana H, Kaminishi H. Candida albicans Msi3p, a homolog of the Saccharomyces cerevisiae Sse1p of the Hsp70 family, is involved in cell growth and fluconazole tolerance. FEMS Yeast Res 2012; 12:728-37. [PMID: 22713118 DOI: 10.1111/j.1567-1364.2012.00822.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/25/2012] [Accepted: 06/14/2012] [Indexed: 11/28/2022] Open
Abstract
We investigated the cellular function of Msi3p, belonging to the heat shock protein 70 family, in Candida albicans. The mutant strain tetMSI3 was generated, in which MSI3 was controlled by a tetracycline-repressive promoter, because there is evidence to suggest that MSI3 is an essential gene. We controlled the MSI3 expression level by doxycycline (DOX) and compared its phenotype with that of a control strain with the tetracycline-repressive promoter and a wild-type copy MSI3. The results indicated that MSI3 was essential for cell growth. In addition, all the tetMSI3-infected mice survived after DOX administration. Drug susceptibility tests indicated that repression of MSI3 expression resulted in hypersensitivity to fluconazole and conferred fungicidal activity to fluconazole. The expression levels of MSI3 and calcineurin-dependent genes were upregulated in response to fluconazole in the control strain. In tetMSI3, the upregulation of MSI3 was lost, and the expression level of the calcineurin-dependent genes was no longer elevated in response to fluconazole and was not affected by DOX, indicating that the upregulation of MSI3 expression was required for the induction of the calcineurin-dependent gene expression. These data suggest that Msi3p confers fluconazole tolerance by partially influencing the calcineurin signaling pathway and also other tolerance mechanisms.
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Affiliation(s)
- Jun-ichi Nagao
- Division of Biomedical Sciences, Department of Functional Bioscience, Section of Infection Biology, Fukuoka Dental College, Fukuoka, Japan
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Abstract
Candidiasis now represents the fourth most frequent nosocomial infection both in the United States and worldwide. Candida albicans is an increasingly common threat to human health as a consequence of AIDS, steroid therapy, organ and tissue transplantation, cancer therapy, broad-spectrum antibiotics, and other immune defects. The pathogenic potential of C. albicans is intimately related to certain key processes, including biofilm formation and filamentation. Ddr48p is a damage response protein that is significantly upregulated during both biofilm formation and filamentation, but its actual function is unknown. Previous studies have indicated that this protein may be essential in C. albicans but not Saccharomyces cerevisiae. Here we examined the function of Ddr48p and investigated the role of this protein in biofilm formation and filamentation. We demonstrated that this protein is not essential in C. albicans and appears to be dispensable for filamentation. However, DDR48 is required for the flocculation response stimulated by 3-aminotriazole-induced amino acid starvation. Furthermore, we examined the response of this deletion strain to a wide variety of environmental stressors and antifungal compounds. We observed several mild sensitivity or resistance phenotypes and also found that Ddr48p contributes to the DNA damage response of C. albicans. The results of this study reveal that the role of this highly expressed protein goes beyond a general stress response and impinges on a key facet of pathogenesis, namely, the ability to sense and respond to changes in the host environment.
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12
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Cleary IA, Reinhard SM, Miller CL, Murdoch C, Thornhill MH, Lazzell AL, Monteagudo C, Thomas DP, Saville SP. Candida albicans adhesin Als3p is dispensable for virulence in the mouse model of disseminated candidiasis. MICROBIOLOGY-SGM 2011; 157:1806-1815. [PMID: 21436220 DOI: 10.1099/mic.0.046326-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The presence of specific proteins, including Ece1p, Hwp1p and Als3p, distinguishes the Candida albicans hyphal cell wall from that of yeast-form cells. These proteins are thought to be important for the ability of C. albicans cells to adhere to living and non-living surfaces and for the cell-to-cell adhesion necessary for biofilm formation, and also to be pivotal in mediating C. albicans interactions with endothelial cells. Using an in vitro flow adhesion assay, we previously observed that yeast cells bind in greater numbers to human microvascular endothelial cells than do hyphal or pseudohyphal cells. This is consistent with previous observations that, in a murine model of disseminated candidiasis, cells locked in the yeast form can efficiently escape the bloodstream and invade host tissues. To more precisely explore the role of Als3p in adhesion and virulence, we deleted both copies of ALS3 in a wild-type C. albicans strain. In agreement with previous studies, our als3Δ null strain formed hyphae normally but was defective in biofilm formation. Whilst ALS3 was not expressed in our null strain, hypha-specific genes such as ECE1 and HWP1 were still induced appropriately. Both the yeast form and the hyphal form of the als3Δ strain adhered to microvascular endothelial cells to the same extent as a wild-type strain under conditions of flow, indicating that Als3p is not a significant mediator of the initial interaction between fungal cells and the endothelium. Finally, in a murine model of haematogenously disseminated candidiasis the mutant als3Δ remained as virulent as the wild-type parent strain.
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Affiliation(s)
- Ian A Cleary
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Sara M Reinhard
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - C Lindsay Miller
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Craig Murdoch
- Academic Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield, Sheffield, UK
| | - Martin H Thornhill
- Academic Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield, Sheffield, UK
| | - Anna L Lazzell
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Carlos Monteagudo
- Departmento de Patología, Facultad de Medicina y Odontología, Universidad de Valencia, 46010 Valencia, Spain
| | - Derek P Thomas
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Stephen P Saville
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
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Suzuki T, Kono K, Tawara SI, Fujimura T, Ito T, Omi K, Ohbuchi K, Komatsu Y, Sakaguchi S, Kamihara T. Unique profiles of changes in cell membrane fluidity during ethanol-induced yeast-to-pseudohyphal transition in Candida tropicalis. J GEN APPL MICROBIOL 2010; 56:321-9. [PMID: 20953096 DOI: 10.2323/jgam.56.321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A dimorphic transition from the yeast form to filamentous one in Candida tropicalis pK233 is triggered by the addition of ethanol into the glucose semi-defined liquid medium and the process of filamentation accompanies temporal depolarization of yeast cells. The transition is completely prevented by further supplementation of myo-inositol at the start of cultivation. The addition of ethanol caused an increase in membrane fluidity during the process of depolarization, and then fluidity was gradually lowered to the level equivalent with that of the stationary-phase yeast cells in accordance with filamentation. The increase in membrane fluidity of ethanol-induced cells appeared parallel with reduction in the content of membrane phosphatidylinositol, which was rich in saturated palmitic acid. Introduction of exogenous myo-inositol or 1 M sorbitol into the ethanol-supplemented culture at the start of cultivation restored yeast growth and the reduction of membrane fluidity occurred, coupled with the recovery of the phosphatidylinositol content.
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Affiliation(s)
- Takahito Suzuki
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara, Japan.
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14
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The transcriptional regulator Nrg1p controls Candida albicans biofilm formation and dispersion. EUKARYOTIC CELL 2010; 9:1531-7. [PMID: 20709787 DOI: 10.1128/ec.00111-10] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The ability of Candida albicans to reversibly switch morphologies is important for biofilm formation and dispersion. In this pathogen, Nrg1p functions as a key negative regulator of the yeast-to-hypha morphogenetic transition. We have previously described a genetically engineered C. albicans tet-NRG1 strain in which NRG1 expression levels can be manipulated by the presence or absence of doxycycline (DOX). Here, we have used this strain to ascertain the role of Nrg1p in regulating the different stages of the C. albicans biofilm developmental cycle. In an in vitro model of biofilm formation, the C. albicans tet-NRG1 strain was able to form mature biofilms only when DOX was present in the medium, but not in the absence of DOX, when high levels of NRG1 expression blocked the yeast-to-hypha transition. However, in a biofilm cell retention assay in which biofilms were developed with mixtures of C. albicans tet-NRG1 and SC5314 strains, tet-NRG1 yeast cells were still incorporated into the mixed biofilms, in which an intricate network of hyphae of the wild-type strain provided for biofilm structural integrity and adhesive interactions. Also, utilizing an in vitro biofilm model under conditions of flow, we demonstrated that C. albicans Nrg1p exerts an exquisite control of the dispersal process, as overexpression of NRG1 leads to increases in dispersion of yeast cells from the biofilms. Our results demonstrate that manipulation of NRG1 gene expression has a profound influence on biofilm formation and biofilm dispersal, thus identifying Nrg1p as a key regulator of the C. albicans biofilm life cycle.
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15
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Pseudohyphal regulation by the transcription factor Rfg1p in Candida albicans. EUKARYOTIC CELL 2010; 9:1363-73. [PMID: 20656914 DOI: 10.1128/ec.00088-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The opportunistic human fungal pathogen Candida albicans is a major cause of nosocomial infections. One of the fundamental features of C. albicans pathogenesis is the yeast-to-hypha transition. Hypha formation is controlled positively by transcription factors such as Efg1p and Cph1p, which are required for hyphal growth, and negatively by Tup1p, Rfg1p, and Nrg1p. Previous work by our group has shown that modulating NRG1 gene expression, hence altering morphology, is intimately linked to the capacity of C. albicans to cause disease. To further dissect these virulence mechanisms, we employed the same strategy to analyze the role of Rfg1p in filamentation and virulence. Studies using a tet-RFG1 strain revealed that RFG1 overexpression does not inhibit hypha formation in vitro or in the mouse model of hematogenously disseminated candidiasis. Interestingly, RFG1 overexpression drives formation of pseudohyphae under yeast growth conditions-a phenotype similar to that of C. albicans strains with mutations in one of several mitotic regulatory genes. Complementation assays and real-time PCR analysis indicate that, although the morphology of the tet-RFG1 strain resembles that of the mitotic regulator mutants, Rfg1p overexpression does not impact expression of these genes.
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Characteristics of Candida albicans biofilms grown in a synthetic urine medium. J Clin Microbiol 2009; 47:4078-83. [PMID: 19794044 DOI: 10.1128/jcm.01377-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Urinary tract infections (UTIs) are the most common type of nosocomial infection, and Candida albicans is the most frequent organism causing fungal UTIs. Presence of an indwelling urinary catheter represents a significant risk factor for UTIs. Furthermore, these infections are frequently associated with the formation of biofilms on the surface of these catheters. Here, we describe the characterization of C. albicans biofilms formed in vitro using synthetic urine (SU) medium and the frequently used RPMI medium and compare the results. Biofilms of C. albicans strain SC5314 were formed in 96-well microtiter plates and on silicon elastomer pieces using both SU and RPMI media. Biofilm formation was monitored by microscopy and a colorimetric XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction assay. As in biofilms grown in RPMI medium, time course studies revealed that biofilm formation using SU medium occurred after an initial adherence phase, followed by growth, proliferation, and maturation. However, microscopy techniques revealed that the architectural complexity of biofilms formed in SU medium was lower than that observed for those formed using RPMI medium. In particular, the level of filamentation of cells within the biofilms formed in SU medium was diminished compared to those in the biofilms grown in RPMI medium. This observation was also corroborated by expression profiling of five filamentation-associated genes using quantitative real-time reverse transcriptase PCR. Sessile C. albicans cells were resistant to fluconazole and amphotericin B, irrespective of the medium used to form the biofilms. However, caspofungin exhibited potent in vitro activity at therapeutic levels against C. albicans biofilms grown in both SU and RPMI media.
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Candida albicans Tup1 is involved in farnesol-mediated inhibition of filamentous-growth induction. EUKARYOTIC CELL 2008; 7:980-7. [PMID: 18424510 DOI: 10.1128/ec.00357-07] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans is a dimorphic fungus that can interconvert between yeast and filamentous forms. Its ability to regulate morphogenesis is strongly correlated with virulence. Tup1, a transcriptional repressor, and the signaling molecule farnesol are both capable of negatively regulating the yeast to filamentous conversion. Based on this overlap in function, we tested the hypothesis that the cellular response to farnesol involves, in part, the activation of Tup1. Tup1 functions with the DNA binding proteins Nrg1 and Rfg1 as a transcription regulator to repress the expression of hypha-specific genes. The tup1/tup1 and nrg1/nrg1 mutants, but not the rfg1/rfg1 mutant, failed to respond to farnesol. Treatment of C. albicans cells with farnesol caused a small but consistent increase in both TUP1 mRNA and protein levels. Importantly, this increase corresponds with the commitment point, beyond which added farnesol no longer blocks germ tube formation, and it correlates with a strong decrease in the expression of two Tup1-regulated hypha-specific genes, HWP1 and RBT1. Tup1 probably plays a direct role in the response to farnesol because farnesol suppresses the haploinsufficient phenotype of a TUP1/tup1 heterozygote. Farnesol did not affect EFG1 (a transcription regulator of filament development), NRG1, or RFG1 mRNA levels, demonstrating specific gene regulation in response to farnesol. Furthermore, the tup1/tup1 and nrg1/nrg1 mutants produced 17- and 19-fold more farnesol, respectively, than the parental strain. These levels of excess farnesol are sufficient to block filamentation in a wild-type strain. Our data are consistent with the role of Tup1 as a crucial component of the response to farnesol in C. albicans.
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Cho T, Aoyama T, Toyoda M, Nakayama H, Chibana H, Kaminishi H. Transcriptional Changes in Candida albicans Genes by Both Farnesol and High Cell Density at an Early Stage of Morphogenesis in N-acetyl-D-glucosamine Medium. ACTA ACUST UNITED AC 2007; 48:159-67. [DOI: 10.3314/jjmm.48.159] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Fang W, Bidochka MJ. Expression of genes involved in germination, conidiogenesis and pathogenesis in Metarhizium anisopliae using quantitative real-time RT-PCR. ACTA ACUST UNITED AC 2006; 110:1165-71. [PMID: 17010593 DOI: 10.1016/j.mycres.2006.04.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 04/04/2006] [Accepted: 04/16/2006] [Indexed: 11/26/2022]
Abstract
Characterization of genes involved in germination, conidiogenesis and insect pathogenesis is an important step in identifying methods to increase the efficacy of Metarhizium anisopliae, a commercially important entomopathogenic fungus. Real-time RT-PCR is a sensitive, reproducible and quantitative method to study gene expression. However, it requires reliable reference gene transcripts for normalization. In this study, six putative housekeeping genes (act, gpd, 18sRNA, tef, try and ubi) were investigated as reliable reference genes. Transcripts from tef, gpd and try were found to be the most suitable reference genes for real-time RT-PCR analysis of genes expressed during germination, conidiogenesis and pathogenesis. Using these as reference genes, the relative expression levels of a virulence gene, a subtilisin-like protease (pr1), a regulator of G protein signaling gene involved in conidiogenesis (cag8), the nitrogen response regulator gene (nrr1), and a hydrophobin gene (ssga) were studied. None of these transcripts could be detected in the early stages of insect pathogenesis. The nitrogen response regulator, nrr1, was consistently expressed during all developmental stages. Expression levels of cag8 increased significantly in the later stages of conidiogenesis on insect cadavers. The expression level of ssga during conidiogenesis was significantly higher than that in mycelia during vegetative growth in nutrient rich media. The pr1 gene was expressed during fungal conidiation on the insect cadaver. This study acts as a foundation for investigating the transcriptional levels of genes expressed during germination, conidiogenesis and pathogenesis of M. anisopliae using real-time RT-PCR.
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Affiliation(s)
- Weiguo Fang
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
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Current awareness on yeast. Yeast 2005; 22:593-600. [PMID: 16003861 DOI: 10.1002/yea.1163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Current Awareness on Comparative and Functional Genomics. Comp Funct Genomics 2005. [PMCID: PMC2447508 DOI: 10.1002/cfg.422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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