Induction of petite mutation with acriflavine and elevated temperature in<i>Candida albicans</i>

Aoki, Shigeji; Ito‐Kuwa, Shoko

doi:10.1080/02681218780000611

Cited by 37 publications

(24 citation statements)

References 14 publications

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“…The respiratory capacity of these yeasts might, however, be transiently inhibited by specific inhibitors and their effects on azole resistance and expression of multidrug resistance genes could be investigated. Among yeast pathogens, mitochondrial mutants have been described only in C. albicans so far (3,10,24), despite the fact that C. albicans was considered a petite-negative yeast (17). Interestingly, C. albicans mitochondrial mutants are resistant to the antimicrobial peptide histatin 5 (10).…”

Section: Discussionmentioning

confidence: 99%

Role of ATP-Binding-Cassette Transporter Genes in High-Frequency Acquisition of Resistance to Azole Antifungals in Candida glabrata

Sanglard

Ischer

Billé

2001

Antimicrob Agents Chemother

234

226

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Candida glabrata has been often isolated from AIDS patients with oropharyngeal candidiasis treated with azole antifungal agents, especially fluconazole. We recently showed that the ATP-binding-cassette (ABC) transporter gene CgCDR1 was upregulated in C. glabrata clinical isolates resistant to azole antifungal agents (D. Sanglard, F. Ischer, D. Calabrese, P. A. Majcherczyk, and J. Bille, Antimicrob. Agents Chemother. 43:2753-2765, 1999). Deletion of CgCDR1 in C. glabrata rendered the null mutant hypersusceptible to azole derivatives and showed the importance of this gene in mediating azole resistance. We observed that wild-type C. glabrata exposed to fluconazole in a medium containing the drug at 50 g/ml developed resistance to this agent and other azoles at a surprisingly high frequency (2 ؋ 10 ؊4 to 4 ؋ 10 ؊4). We show here that this high-frequency azole resistance (HFAR) acquired in vitro was due, at least in part, to the upregulation of CgCDR1. The CgCDR1 deletion mutant DSY1041 could still develop HFAR but in a medium containing fluconazole at 5 g/ml. In the HFAR strain derived from DSY1041, a distinct ABC transporter gene similar to CgCDR1, called CgCDR2, was upregulated. This gene was slightly expressed in clinical isolates but was upregulated in strains with the HFAR phenotype. Deletion of both CgCDR1 and CgCDR2 suppressed the development of HFAR in a medium containing fluconazole at 5 g/ml, showing that both genes are important mediators of resistance to azole derivatives in C. glabrata. We also show here that the HFAR phenomenon was linked to the loss of mitochondria in C. glabrata. Mitochondrial loss could be obtained by treatment with ethidium bromide and resulted in acquisition of resistance to azole derivatives without previous exposure to these agents. Azole resistance obtained in vitro by HFAR or by agents stimulating mitochondrial loss was at least linked to the upregulation of both CgCDR1 and CgCDR2.

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Section: Discussionmentioning

confidence: 99%

Role of ATP-Binding-Cassette Transporter Genes in High-Frequency Acquisition of Resistance to Azole Antifungals in Candida glabrata

Sanglard

Ischer

Billé

2001

Antimicrob Agents Chemother

234

226

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“…Respiratory-deficient mutants were obtained by culturing C. albicans MEN for 5 days at 37°C and 200 rpm in an orbital incubator in YEPD broth supplemented with 25 μg ethidium bromide (Sigma-Aldrich) ml -1 as described (Aoki and Ito-Kuwa 1987). Respiratory-deficient mutants were selected by their inability to grow on glycerol.…”

Section: Isolation Of Respiratory-deficient Mutantsmentioning

confidence: 99%

“…Respiratory-deficient mutants (frequently referred to as petite mutants) are difficult to isolate in C. albicans (Aoki and Ito-Kuwa 1987;Abu-Hatab and Whittaker 1992) whereas they arise spontaneously in Saccharomyces cerevisiae at a rate of approximately 0.1% of cells per generation. S. cerevisiae petite mutants grow at a lower rate than their parents and are incapable of metabolising glycerol, have disrupted cytochromes and reduced rates of oxygen consumption (Gyurko et al 2000;Aoki et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Disruption of mitochondrial function in Candida albicans leads to reduced cellular ergosterol levels and elevated growth in the presence of amphotericin B

Geraghty

Kavanagh

2003

Arch Microbiol

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A respiratory-deficient mutant of Candida albicans MEN was generated by culturing cells in medium supplemented with ethidium bromide at 37°C for 5 days. The respiratory-deficient mutant (C. albicans MMU11) was incapable of growth on glycerol, had a reduced oxygen uptake rate and demonstrated an altered mitochondrial cytochrome profile. Respiratory-competent cybrids were formed by mitochondrial transfer following fusion of protoplasts with those of C. albicans ATCC 44990. Mutant MMU11 possessed lower levels of ergosterol than the parental isolates and the cybrids, and demonstrated a small but statistically significant increase in tolerance to amphotericin B. The results demonstrated that disruption of mitochondrial function in C. albicans increases the tolerance to amphotericin B, possibly mediated by a reduction in cellular ergosterol content.

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“…The growth of petite mutants is limited to fermentable carbon sources such as glucose or sucrose, but they fail to grow on glycerol and ethanol (2,34). Cytochrome determinations show that petite mutants are lacking either cytochrome b or cytochrome aa 3 or both but always retain cytochrome c (6,10,35). The molecular basis of the petite phenotype is mutation or deletion of mitochondrial genes (9).…”

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confidence: 99%

“…For Saccharomyces cerevisiae such petite mutants have been known for a long time (8), but petite mutants of C. albicans were thought not to be viable (5). However, recent work indicates that petite mutants of C. albicans can be used to study a host of biological questions related to mitochondrial function (2,3,14,32). Such mutants form only tiny, so-called petite, colonies because their cell division rates are lower than that of the normal cells and their biomass yield on glucose is decreased (8,34,36).…”

mentioning

confidence: 99%

Candida albicansMutants Deficient in Respiration Are Resistant to the Small Cationic Salivary Antimicrobial Peptide Histatin 5

Gyurko

Lendenmann

Troxler

et al. 2000

Antimicrob Agents Chemother

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Histatins are a group of small cationic peptides in human saliva which are well known for their antibacterial and antifungal activities. In a previous study we demonstrated that histatin 5 kills both blastoconidia and germ tubes of Candida albicans in a time-and concentration-dependent manner at 37°C, whereas no killing was detected at 4°C. This indicated that killing activity depends on cellular energy. To test histatin 5 killing activity at lower cellular ATP levels at 37°C, respiratory mutants, or so-called petite mutants, of C. albicans were prepared. These mutants are deficient in respiration due to mutations in mitochondrial DNA. Mutants were initially identified by their small colony size and were further characterized with respect to colony morphology, growth characteristics, respiratory activity, and cytochrome spectra. The killing activity of histatin 5 at the highest concentration was only 28 to 30% against respiratory mutants, whereas 98% of the wild-type cells were killed. Furthermore, histatin 5 killing activity was also tested on wild-type cells in the presence of the respiratory inhibitor sodium azide or, alternatively, the uncoupler carbonyl cyanide m-chlorophenylhydrazone. In both cases histatin 5 killing activity was significantly reduced. Additionally, supernatants and pellets of cells incubated with histatin 5 in the presence or absence of inhibitors of mitochondrial ATP synthesis were analyzed by sodium dodecyl sulfate gel electrophoresis. It was observed that wild-type cells accumulated large amounts of histatin 5, while wild-type cells treated with inhibitors or petite mutants did not accumulate significant amounts of the peptide. These data showed first that cellular accumulation of histatin 5 is necessary for killing activity and second that accumulation of histatin 5 depends on the availability of cellular energy. Therefore, mitochondrial ATP synthesis is required for effective killing activity of histatin 5.

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Induction of petite mutation with acriflavine and elevated temperature inCandida albicans

Cited by 37 publications

References 14 publications

Role of ATP-Binding-Cassette Transporter Genes in High-Frequency Acquisition of Resistance to Azole Antifungals in Candida glabrata

Role of ATP-Binding-Cassette Transporter Genes in High-Frequency Acquisition of Resistance to Azole Antifungals in Candida glabrata

Disruption of mitochondrial function in Candida albicans leads to reduced cellular ergosterol levels and elevated growth in the presence of amphotericin B

Candida albicansMutants Deficient in Respiration Are Resistant to the Small Cationic Salivary Antimicrobial Peptide Histatin 5

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