Bidirectional Stimulation of the White-Opaque Transition of Candida albicans by Ultraviolet Irradiation

Morrow, Brian J.; Anderson, Julia M.; Wilson, Jane; Soll, David R.

doi:10.1099/00221287-135-5-1201

Cited by 44 publications

(52 citation statements)

References 17 publications

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“…This model suggests that most, if not all, stressful environments could potentially induce white-opaque switching by inhibiting rates of cell growth. It also has important implications for other studies on phenotypic switching, as changes in switching frequencies previously observed (e.g., in response to UV irradiation; Morrow et al, 1989) may simply be due to indirect effects of the test conditions on cell generation times.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that exogenous factors, such as UV irradiation, increase switching from white to opaque in C. albicans (Morrow et al, 1989;Kolotila and Diamond, 1990). We hypothesized that white-opaque switching may be induced as part of a general response to cell stress in white cells; therefore, we examined whether other types of genotoxic stress could induce switching to opaque.…”

Section: Genotoxic Stress Induces White-opaque Switching In C Albicansmentioning

confidence: 99%

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Stress-Induced Phenotypic Switching inCandida albicans

Alby

Bennett

2009

MBoC

111

108

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Candida albicans is both a common commensal and an opportunistic pathogen, being a prevalent cause of mucosal and systemic infections in humans. Phenotypic switching between white and opaque forms is a reversible transition that influences virulence, mating behavior, and biofilm formation. In this work, we show that a wide range of factors induces high rates of switching from white to opaque. These factors include different forms of environmental stimuli such as genotoxic and oxidative stress, as well as intrinsic factors such as mutations in DNA repair genes. We propose that these factors increase switching to the opaque phase via a common mechanism-inhibition of cell growth. To confirm this hypothesis, growth rates were artificially manipulated by varying expression of the CLB4 cyclin gene; slowing cell growth by depleting CLB4 resulted in a concomitant increase in white-opaque switching. Furthermore, two clinical isolates of C. albicans, P37005 and L26, were found to naturally exhibit both slow growth and high rates of white-opaque switching. Notably, suppression of the slow growth phenotype suppressed hyperswitching in the P37005 isolate. Based on the sensitivity of the switch to levels of the master regulator Wor1, we propose a model for how changes in cellular growth modulate white-opaque switching frequencies.

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Section: Discussionmentioning

confidence: 99%

Section: Genotoxic Stress Induces White-opaque Switching In C Albicansmentioning

confidence: 99%

Stress-Induced Phenotypic Switching inCandida albicans

Alby

Bennett

2009

MBoC

111

108

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“…Various genetic mechanisms have been invoked to explain the molecular basis of phenotypic transitions in C. albicans (Morrow et al, 1989;Pomts et al, 1987;Rustchenko-Bulgac et al, 1990;Scherer & Stevens, 1988;Slutsky et al, 1985;Sol1 et al, 1987;Suzuki et al, 1989) Our results suggest that some environmental conditions (i.e. the growth medium and/or the incubation temperature) may differentially affect expression of a set of genes (which among other possibilities, may change the activity of enzymes that synthesize wall components) responsible for the manifestation of differ- Table 3), cells were inoculated into liquid YPD medium and rotated on a gyratory incubator (250 r.p.m.)…”

Section: Discussionmentioning

confidence: 99%

Wall mannoproteins in cells from colonial phenotypic variants of Candida albicans

Martinez

Gil

Casanova

et al. 1990

Journal of General Microbiology

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Candida albicans ATCC 26555 switched at high frequency (10-l to between several phenotypes identified by colony morphology on a defined mineral amino-acid-containing agar medium supplemented with arginine and zinc (LAZ medium). When cells taken from colonies exhibiting distinct morphologies were plated directly onto LAZ agar, spontaneous conversion to all the variant phenotypes occurred at combined frequencies of 2-1 x 10-l to xHowever, when cells taken from the different colonial phenotypes were plated directly onto an undefined medium (yeast extract/peptone/dextrose; YPD medium), or first incubated in liquid YPD medium and then cloned on YPD agar, all colonies observed exhibited the same phenotype (smooth-white). When cells from the smooth-white colonies were plated as clones on LAZ agar, the original switch phenotype reappeared. These results suggest that environmental conditions such as the growth medium (and possibly the temperature) influence switching by suppressing phenotype expression, but have no effect on genotype. The variant colony morphologies also appeared to be associated with differences in the relative proportions of yeast and mycelial cells. Zymolyase digests of wall preparations obtained from cells belonging to different colonial phenotypes were analysed by SDS-PAGE. After blotting to nitrocellulose paper, the mannoproteins were stained with Concanavalin A, with a polyclonal antiserum enriched in antibodies against mycelium-specific wall components, and with a monoclonal antibody raised against a high-molecular-mass mannoprotein band (260 kDa) specific to the walls of mycelial cells. The results suggest that phenotypic switching might be associated with changes in the degree of glycosylation in high-molecular-mass mannoproteins, or in the way these mannoproteins are bound to other cell wall components.

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“…The cotton end of each swab was inserted into 0.5 ml sterile water in a polypropylene test tube and mixed vigorously for 30 s with a vortex mixer. A 0.15 ml sample of the swab wash was spread onto each of two agar plates containing supplemented Lee's medium (Lee et al, 1975;Morrow et al, 1989) and incubated for 7 days at 25 uC (Vargas et al, 2000). The plates were verified for the different phenotypes such as smooth white, irregular wrinkle, star, ring, myceliated and heavily myceliated.…”

Section: Virulence Factorsmentioning

confidence: 99%