Candida albicans Strain-Dependent Virulence and
Rim13p-Mediated Filamentation in
Bradley M. Mitchell,1,2Tzu G. Wu,1Beth E. Jackson,1and Kirk R. Wilhelmus1
PURPOSE. To compare the virulence of wild-type Candida al-
bicans strains in a murine model of corneal candidiasis and to
investigate the role of fungal filamentation in disease progres-
METHODS. Scarified corneas of immunocompetent or cyclo-
phosphamide-treated BALB/c mice were topically inoculated
with one of three human isolates of C. albicans, a homozygous
mutant of the pH-dependent filamentation gene rim13 or a
mutant reference strain control. Mock-inoculated eyes served
as negative controls. Corneal disease was categorized daily for
8 days with quantitative fungal culturing of eyes at 6 hours, 1
day, 4 days, and 8 days after infection and histopathologic
examination at 1 day and 4 days after infection.
RESULTS. Corneal disease severity differed significantly among
wild-type strains (P ? 0.02). The rim13–/–mutant Tn7-rim13
was fully attenuated, whereas the mutant control DAY286 was
fully virulent. Pretreatment of mice with cyclophosphamide
increased susceptibility to wild-type C. albicans and partially
rescued the attenuated phenotype of the genetically deficient
rim13–/–fungal mutant. All strains replicated with similar ki-
netics in vitro, and wild-type strains had similar clearance from
infected eyes. Histopathologic findings correlated with disease
CONCLUSIONS. Wild-type strains of C. albicans that differ signif-
icantly in ocular pathogenicity correlate with the ability of
yeast to produce pseudohyphae and hyphae and to invade
corneal tissue. Full attenuation of the fungal rim13–/–mutant is
the first direct demonstration of a hyphal morphogenesis-re-
lated gene as a specific virulence factor for C. albicans during
corneal infection. (Invest Ophthalmol Vis Sci. 2007;48:
Candida albicans is found on the ocular surface of up to one
third of otherwise healthy persons.1–4Although this fungal
species is typically commensal, severe ocular disease develops
under certain conditions. How this shift to pathogenic invasion
occurs is still unclear, but the transition is finely balanced and
genetically regulated.5Fungal mechanisms crucial for mucosal
and systemic infection by C. albicans include adherence, ger-
mination, production of extracellular proteinases and phos-
pseudohyphae and hyphae.6–9Previous work has suggested
that the conversion to filamentous forms contributes to ocular
virulence of C. albicans.10,11
Environmental cues such as pH12,13influence filamentation
growth of Candida, Saccharomyces, and Aspergillus through
a conserved alkaline-response pathway.14,15Mutant strains un-
able to grow at a given pH in vitro are less capable of infecting
selective sites in vivo.16,17This system, called the RIM101
pathway or the PacC pathway, depending on fungal genus,18is
governed by the zinc finger–containing transcription factor
Rim101p/PacC.15,19–21In acidic conditions, Rim101p is full-
length and inactive, whereas in neutral to alkaline conditions
its C-terminal portion is cleaved, resulting in activation of the
protein that regulates gene expression.22–24Several gene prod-
ucts are required for this proteolytic processing, including
Rim8p/PalF, Rim9p/PalI, Rim13p/PalB, Rim20p/PalA, and
Rim21p/PalH.24,25Rim13p/PalB is a calpain-like protease that
cleaves the C-terminal glutamate-aspartate-rich domain of
Rim101p during activation.18
Because of the complex life cycle of fungi, investigating the
pathogenesis of oculomycosis requires in vivo models that
allow high reproducibility and sensitive quantitation.10,11,26–28
This study compared the degrees of virulence of three different
C. albicans wild-type strains in mice and evaluated the contri-
bution of the RIM101 signal transduction pathway.15,20,21Our
findings provide direct evidence for the importance of filamen-
tation in keratomycosis and demonstrate that a morphogenesis-
related fungal gene is a specific virulence factor for C. albicans
during corneal infection.
MATERIALS AND METHODS
Three wild-type strains of C. albicans originally isolated from human
infection, a Tn7 transposon mutant, and a mutant control reference
strain were evaluated. Strain VE175 is a corneal isolate that has been
used to induce experimental keratomycosis in rabbits.29Strain B311
(ATCC 32354; American Type Culture Collection, Rockville, MD) is an
isolate that is highly virulent in mice when injected intravenously30and
that causes ocular disease in mice after corneal inoculation.11Strain
SC5314 has been used extensively for genetic studies of C. albicans
and experimentally causes corneal disease in rabbits.29,31Strain Tn7-
rim13 is a homozygous mutant with a transposon insertion at position
239 of the rim13 coding sequence18that was transformed into strain
BWP17,15a derivative of strain SC5314, as part of a homozygous
insertion mutant library.32The mutant control reference strain
DAY286 has a Ura?Arg?His?genotype and was created by the trans-
formation of strain BWP17.15
All yeast strains were grown on Sabouraud dextrose agar (Difco,
Detroit, MI) for 3 days at 25°C. For corneal inoculation, the yeasts were
harvested and diluted in sterile phosphate-buffered saline (PBS) to yield
Cullen Eye Institute, Department of Ophthalmology, and the2Depart-
ment of Molecular Virology and Microbiology, Baylor College of Med-
icine, Houston, Texas.
Supported by a clinical investigator award (EY00377), cooperative
agreement (EY09696), and core grant (EY02520) from the National Eye
Institute; a senior scientific investigator award and grant from Research
to Prevent Blindness, Inc.; the J. S. Abercrombie Foundation; the Retina
Research Foundation; and the Sid W. Richardson Foundation.
Submitted for publication July 12, 2006; revised September 5,
2006; accepted December 1, 2006.
Disclosure: B.M. Mitchell, None; T.G. Wu, None; B.E. Jackson,
None; K.R. Wilhelmus, None
The publication costs of this article were defrayed in part by page
charge payment. This article must therefore be marked “advertise-
ment” in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Corresponding author: Kirk R. Wilhelmus, Department of Oph-
thalmology, NC-205, Baylor College of Medicine, 6565 Fannin, Hous-
ton, TX 77030; email@example.com.
1Sid W. Richardson Ocular Microbiology Laboratory,
Investigative Ophthalmology & Visual Science, February 2007, Vol. 48, No. 2
Copyright © Association for Research in Vision and Ophthalmology
1 ? 105or 1 ? 106colony-forming units (CFU)/5 ?L inoculum based
on optical density (OD) at 600 nm and using a conversion factor of 1
U OD600equal to approximately 3 ? 107CFU/mL based on Saccharo-
myces33and confirmed for Candida.11For the in vitro growth kinetics
study, yeasts were collected from the agar plates and diluted in Sab-
ouraud dextrose broth (Difco).
Adult female BALB/c mice (Harlan Sprague-Dawley, Houston, TX) were
used at 6 to 8 weeks of age. A subset of mice was pretreated 5 days, 3
days, and 1 day before corneal inoculation with intraperitoneal injec-
tions of cyclophosphamide (Sigma, St. Louis, MO) at 180 mg/kg body
weight, as previously described.11This regimen and dose of cyclophos-
phamide results in severe immunosuppression and induces a biological
effect within ocular tissues.11Mice were anesthetized and corneally
scarified as previously described.11Five microliters (1 ? 105or 1 ? 106
CFU) inoculum of C. albicans was applied to the scarified corneas.
Mice that were scarified and received mock inoculation with sterile
PBS served as negative controls. All animals were treated in accordance
with the ARVO Statement for the Use of Animals in Ophthalmic and
Vision Research, and the protocols were approved by the Baylor
College of Medicine Institutional Animal Care and Use Committee.
In Vitro Growth Kinetics
One thousand CFU of each C. albicans strain were inoculated into 2
mL Sabouraud dextrose broth and incubated at 27°C with continuous
rocking for 7 days. Two milliliters mock-inoculated Sabouraud dex-
trose broth served as a negative control. Results of two independent
experiments performed in triplicate were averaged. The broth was
sampled at 6, 9, 22, 34, 50, 76, 96, and 168 hours after inoculation for
in vitro growth by measuring the OD600and using the conversion
factor of 3 ? 107CFU/mL per 1 U OD600.11,33Statistical analyses were
determined with Student’s t test.
All mice were monitored daily for corneal involvement for up to 8 days
postinoculation (p.i.). The severity of keratomycosis was scored with
the aid of a dissecting microscope. A grade of 0 to 4 was assigned to
each of three criteria: area of opacity, density of opacity, and surface
regularity.11,28Scores from each category were tallied daily for each
eye to yield a possible total score of 0 to 12. A total score of 1 to 5 was
categorized as mild eye disease, a total score from 5 to 9 was consid-
ered moderate, and a total score greater than 9 was considered se-
vere.11Results were evaluated for statistical significance by the
Kruskal-Wallis one-way analysis of variance on ranks. Pairwise multiple
comparison procedures included the Dunn method and the Tukey test.
Quantitative Isolate Recovery
Mice were killed and eyes were enucleated at 6 hours, 1 day, 4 days,
and 8 days p.i. and were processed for microbial culturing. Eyes from
infected and mock-infected mice were individually ground in a frosted
glass grinder, as previously described.11A 0.5-mL homogenate aliquot
was fourfold serially diluted in Sabouraud dextrose broth containing
chloramphenicol 50 ?g/mL and incubated at 27°C. After 4 days of
incubation, the last blank in the serial dilution that had visible yeast
growth was recorded as the titration end point and then was examined
by subculture and microscopy. Results were analyzed with Student’s t
Mice used for histologic examination were killed, and the eyes were
enucleated at 1 day and 4 days p.i. Eyes from C. albicans–infected and
mock-infected mice were formalin-fixed, paraffin-embedded, and sec-
tioned at a thickness of 8 ?m for histologic study. Sections were
deparaffinized and stained with Grocott methenamine silver (GMS;
Richard-Allan Scientific, Kalamazoo, MI) or periodic acid-Schiff (PAS;
In Vitro Growth Kinetics of Wild-type
C. albicans Strains
To determine whether inherent growth differences existed
among the strains of C. albicans, the growth rates of strains
VE175, B311, and SC5314 were evaluated in vitro. The overall
growth kinetics of the three different strains was similar, with
all three strains demonstrating similar lag, log-growth, and
plateau phases (Fig. 1). Mock-inoculated negative control cul-
tures remained negative for growth throughout the 7-day
study. The results suggested that all three strains replicated at
similar rates under controlled in vitro conditions and that no
strain demonstrated an apparent growth advantage or disad-
Visual Examination of Keratomycosis in Mice
Infected with Wild-type C. albicans Strains
After the inoculation of 1 ? 106CFU of C. albicans, mice were
visually evaluated daily for 8 days and scored for corneal in-
volvement (Fig. 2). Mice infected with strain VE175 developed
only mild keratomycosis by 24 hours p.i. that became signifi-
cantly less severe by day 8 (day 1 vs. day 8; P ? 0.001). Mice
infected with strain B311 developed moderate keratomycosis
on day 1 that persisted through day 4 (day 1 vs. day 4; P ? 0.7)
but that became less severe on and after day 5 (day 1 vs. day 5;
P ? 0.04). Mice infected with strain SC5314 also developed
moderate keratomycosis, but corneal involvement remained
moderate to severe through day 8 (day 1 vs. day 8; P ? 0.9). As
previously reported,11all mock-infected corneas had mild sur-
face irregularities and swelling at 6 hours after the corneal
scarification procedure but regained the normal appearance of
a naive eye within 24 hours and then remained unchanged.
Mice infected with strain B311 had significantly more disease
VE175, B311, and SC5314. One thousand CFU of each cultured Can-
dida albicans strain were inoculated into Sabouraud dextrose broth
and monitored for growth for 7 days by optical density at a wavelength
of 600 nm (OD600). Mean OD600measurements (? SD) of six samples
from two independent experiments are plotted. The lowest points
plotted on the graph represent the optical density of the broth used as
diluent and for blanking the spectrophotometer.
In vitro growth kinetics of Candida albicans strains
IOVS, February 2007, Vol. 48, No. 2
Candida Virulence in Keratomycosis 775
than mice infected with strain VE175 from day 1 through day
4 (P ? 0.001). However, disease with strain B311 improved
from day 5 through day 8 and became similar to disease with
strain VE175 (P ? 0.2 for day 5 through day 8). Corneal disease
with strain SC5314 was significantly greater than that caused
by strain VE175 at all time points (P ? 0.001). Representative
findings from day 4 and day 8 are shown in Figure 3.
Quantitative Isolate Recovery of C. albicans
To correlate visible eye disease to fungal load within ocular
tissues, mouse corneas were scarified and individually infected
with 1 ? 106CFU of one of the three C. albicans strains or
were mock-infected and analyzed by end point titration at 6
hours, 1 day, 4 days, and 8 days p.i. As shown in Figure 4, the
rates of fungal clearance in mice were similar among the three
strains at all time points evaluated (P ? 0.1). Strains VE175,
B311, and SC5314 were cleared from ocular tissues with sig-
nificantly fewer organisms recovered from the infected cor-
neas on day 8 compared with day 1 (P ? 0.009 for all three
strains). No C. albicans was recovered from mock-infected
corneas at any time.
Histopathology of Mouse Eyes Infected with Wild-
type C. albicans Strains
Histologic examination of infected eyes harvested 1 day and 4
days p.i. revealed invading yeasts in the corneal epithelium and
the stroma. Corneas of infected animals showed epithelial
thickening and varying degrees of stromal edema and inflam-
mation. Massive hyphal formation was present in the cornea 1
day p.i. for strain SC5314 (Fig. 5A), but the yeast form was
predominant 4 days p.i. The yeast form and some pseudohy-
phae were typically seen in VE175-infected animals, with the
infection primarily more superficial and affecting the corneal
epithelium and anterior portion of the stroma (Fig. 5B). Neu-
trophilic infiltration and edematous corneal stroma were prom-
inent in corneas infected with strain SC5314, less severe with
strain B311, and minimal with strain VE175 at 4 days p.i.
Mock-infected eyes did not show signs of infection or inflam-
strains VE175, B311, and SC5314. Immunocompetent BALB/c mice
were mock-infected or infected with 106CFU of C. albicans and
visually evaluated for their corneal involvement for 8 days. Mock-
infected corneas received sterile PBS and served as controls. A total
score less than 5 was categorized as mild disease, from 5 to 9 was
considered moderate, and greater than 9 was severe. Each point rep-
resents the mean score (? SD) of 9 to 48 eyes.
Severity of murine keratomycosis induced by C. albicans
murine keratomycosis induced by C.
albicans strains VE175, B311, and
SC5314. Corneas of immunocompe-
tent BALB/c mice were mock-in-
fected or infected with 106CFU C.
albicans and were photographed 1
day, 4 days, and 8 days after inocula-
Clinical progression of
776 Mitchell et al.
IOVS, February 2007, Vol. 48, No. 2
mation but did have residual microscopic epithelial changes
from the initial scarification procedure.
Evaluation of Rim13p for C. albicans Virulence
during Corneal Infection
To exclude any inherent growth differences for the homozy-
gous rim13–/–mutant Tn7-rim13 or its mutant-control refer-
ence strain DAY286, growth rates were evaluated in vitro and
compared with those of SC5314. The overall growth kinetics of
Tn7-rim13 and DAY286 were similar to those of SC5314, with
no significant difference at any of the growth phases (Fig. 6).
Mutant strains replicated at similar rates under controlled in
vitro conditions, and no obvious growth advantage or disad-
vantage occurred compared with the wild-type strains used in
To determine the potential contribution of Rim101p-medi-
ated filamentation on the virulence of C. albicans during cor-
neal infection, Tn7-rim13 and DAY286 were compared with
their progenitor wild-type strain SC5314. After inoculation of
1 ? 106CFU of each strain on the scarified corneas of immu-
nocompetent mice, eyes were observed daily for 8 days and
were scored for corneal involvement (Fig. 7). DAY286 induced
severe keratitis indistinguishable from that caused by strain
SC5314 throughout the 8 days of observation. Tn7-rim13 was
fully attenuated, which caused only slight corneal opacity at
day 1 that resolved by day 2 and remained clear through day 8.
Differences in disease severity between Tn7-rim13 compared
with SC5314 and DAY286 were significantly different (P ?
Histopathologic evaluation 1 day and 4 days p.i. of eyes
from immunocompetent mice infected with 1 ? 106CFU of
strains DAY286 and Tn7-rim13 correlated with disease severity
(data not shown). Similar to SC5314, DAY286 infection re-
sulted in invading yeasts in the corneal epithelium and the
stroma, epithelial thickening, and varying degrees of stromal
edema and inflammation. Neutrophilic infiltration and edema-
tous corneal stroma were also prominent in corneas infected
with strain DAY286. Hyphal formation was present in the
cornea 1 day p.i., but the yeast form was predominant at 4 days
p.i. Eyes infected with Tn7-rim13 were essentially histologi-
cally normal except for an occasional adherent yeast form and
mild epithelial changes from the initial scarification procedure.
Effect of Systemic Immunosuppression on
Experimental C. albicans Keratitis
Immunosuppression increases the susceptibility of the host to
infection and increases keratitis severity.11,34To evaluate the
effect of immunosuppression on the attenuated phenotype of
the rim13 mutant, immunocompetent (Fig. 8A) or cyclophos-
phamide-treated mice (Fig. 8B) were infected with 1 ? 105
CFU of strains Tn7-rim13, DAY286, or SC5314 and were mon-
itored for 8 days. SC5314 and DAY286 induced moderate
keratitis in immunocompetent mice that began resolving on
day 4 and subsided to mild disease on the final days of the
study. At no time was disease severity between these two
strains significantly different (P ? 0.13). Eyes exposed to Tn7-
rim13 remained disease free, which was significantly different
from keratitis caused by SC5314 and DAY286 (P ? 0.01).
Pretreatment of mice with cyclophosphamide increased cor-
neal disease severity, resulting in mean disease scores in the
severe range for SC5314 and DAY286 at all time points during
the 8-day evaluation. Immunosuppressive treatment partially
restored virulence to strain Tn7-rim13, resulting in mean dis-
C. albicans wild-type strains SC5314 and VE175. Mouse corneas were
mock-infected or infected with 106CFU of C. albicans and enucleated
1 day and 4 days later. Paraffin-embedded eyes were sectioned at a
thickness of 8 ?m and stained with PAS. Representative findings 1 day
after infection are shown. (A) In SC5314-infected eyes, abundant fungi
and corneal edema were evident in both the epithelium (E) and the
corneal stroma (S). Pseudohyphae and hyphae were the predominant
fungal forms. (B) VE175-infected eyes showed significantly fewer or-
ganisms and less edema and neutrophilic inflammation relative to
SC5314-infected eyes. Budding yeasts (arrows) were the predominant
fungal forms. Original magnification: (A) ?200; (B) ?400.
Histopathologic views of murine keratomycosis induced by
albicans from infected corneas. Corneas of immunocompetent BALB/c
were mock-infected or infected with 106CFU of C. albicans strain
VE175, B311, or SC5314 and analyzed by end point titration at 6 hours,
1 day, 4 days, and 8 days after inoculation. Mock-infected corneas
received only sterile PBS. Culture-positive end points were converted
to CFU, and the mean (? SD) of six eyes per time point are plotted.
The lowest points plotted on the graph represent the lower limit of
detection by the assay.
Quantitative isolate recovery of three different strains of C.
IOVS, February 2007, Vol. 48, No. 2
Candida Virulence in Keratomycosis 777
ease severity that increased to moderate levels, peaked at 3
days p.i., and resolved to mild levels with only slight corneal
opacity. Even with the elevation in disease severity of cyclo-
phosphamide-treated mice infected with Tn7-rim13, the mean
degree of eye disease was significantly less than that observed
for strains SC5314 and DAY286, except at day 3, the peak of
corneal involvement (P ? 0.036).
Candida keratitis is an opportunistic infection.35C. albicans
can be acquired as the result of eye trauma or surgery, and it is
an occasional contaminant encountered by corneal transplant
recipients,36bandage contact lens wearers,37and patients with
chronic ocular surface disease.38Experimental murine kerato-
mycosis is a reliable mammalian system for understanding the
pathogenesis of human ocular infection.11This model allows
quantitative assessment of disease severity and is suitable for
comparing virulence differences among fungal strains and mu-
Specific virulence factors involved in C. albicans corneal
infection are unknown but may be similar to mechanisms
controlling candidal adherence and invasion during candidiasis
of other organs and tissues.39Phenotypic switching—the abil-
ity of yeasts to form filamentous cells—is a crucial step in
dissemination and infection. O’Day et al.29correlated C. albi-
cans hyphal penetration with corneal disease severity in a
rabbit model, and we recently reported an association between
hyphal and pseudohyphal forms of C. albicans with more
severe corneal disease in immunosuppressed mice.11
In the present study we used a murine model to compare
the corneal pathogenicity of three wild-type strains of C. albi-
cans, a pH-mediated filamentation gene mutant, and a mutant
reference strain control using clinical, microbiologic, and his-
topathologic methods. These C. albicans strains caused kera-
tomycosis with different degrees of severity, suggesting that, as
in systemic and other mucosal infections, C. albicans uses
virulence factors during corneal infection.
Corneal disease caused by candidal strain SC5314 was sig-
nificantly more severe than that caused by strain B311 or
VE175. Histologic analysis further indicated that strain SC5314
was more invasive than the other two strains, with fungi
penetrating more deeply into the corneal stroma. These results
are consistent with previous results from the rabbit model.10
By the fourth day of experimental infection, the amounts of
pseudohyphae, severe stromal edema, structural destruction,
Tn7-rim13, and DAY286. One thousand CFU of each cultured C. albi-
cans strain were inoculated into Sabouraud dextrose broth and mon-
itored for growth for 7 days. Optical density measurements were
converted to CFU/mL, and the mean (? SD) of six samples from two
independent experiments are plotted.
In vitro growth kinetics of C. albicans strains SC5314,
cans strains SC5314, DAY286, and Tn7-rim13 at 1 ? 106CFU. Immu-
nocompetent BALB/c mice were mock-infected or infected with 106
CFU of C. albicans and evaluated for 8 days. Each point represents the
mean score (? SD) of 5 to 18 eyes.
The severity of murine keratomycosis induced by C. albi-
strains SC5314, DAY286, and Tn7-rim13 at 1 ? 105CFU. Immunocom-
petent BALB/c mice (A) or mice pretreated with cyclophosphamide
(B) were mock-infected or infected with 105CFU of C. albicans and
evaluated for 8 days. Each point represents the mean score (? SD) of
17 to 35 eyes from immunocompetent mice and three to five eyes from
Severity of murine keratomycosis induced by C. albicans
778Mitchell et al.
IOVS, February 2007, Vol. 48, No. 2
and inflammation were more evident in corneas infected with
strain SC5314 than in those infected with strain B311 or
The greater virulence of strain SC5314 was not caused by an
inherently accelerated rate of replication because all three
strains had similar in vitro growth kinetics. Colonization factors
mediating adherence are also unlikely to explain the corneal
virulence of C. albicans because, at early stages of infection,
similar numbers of viable organisms were recovered from in-
fected corneas. Fungal clearance from the murine cornea was
also similar for all three wild-type strains. This disparity be-
tween in vivo growth and clinical and histopathologic severity
was also found in experimental C. albicans keratitis of rab-
bits.10Our results and those of O’Day et al.29show that though
the fungal load may be partially indicative of microbial repli-
cation and clearance, it is inadequate for predicting the disease
severity or invasiveness of the infecting organism.
Based on previous reports28,29and our current findings
from studies using the wild-type strains of C. albicans, we
speculate that the virulence factors involved in regulating phe-
notypic switching contribute to fungal penetration into the
corneal stroma and account for differences in disease severity.
Virulent strains SC5314 and B311 are induced to filament in
vitro by growth at pH 8, but the less virulent strain VE175 fails
to filament (data not shown). A shifting corneal microenviron-
ment around colonizing yeasts could induce the candidal
Rim101 pathway.40Genetically regulated fungal filamentation
would facilitate stromal invasion and trigger an inflammatory
We previously showed that host factors, including immune
status and genetic background, contribute to the outcome of
murine keratomycosis caused by C. albicans11and Fusarium
solani.28Our current results are an extension of these findings.
Pretreatment of mice with cyclophosphamide resulted in more
severe disease for wild-type and mutant strains of C. albicans.
Immunosuppressive treatment restored virulence partially, but
not completely, to the rim13 mutant, suggesting that host
factors and infecting pathogen factors influence disease profile.
Our current findings demonstrate that various strains of C.
albicans have inherent differences in pathogenic potential.
Furthermore, our studies using a homozygous rim13 mutant
provide direct evidence that filamentation is important for C.
albicans virulence during corneal infection and indicate that a
hyphal morphogenesis-related gene is a virulence factor for
fungal keratitis. The pronounced attenuation observed for
strain Tn7-rim13 is consistent with the role of fungal filamen-
tation in candidiasis and supports the concept of developing
therapeutic approaches targeting the Rim101 signal transduc-
tion pathway. The experimental murine keratomycosis model
will be useful for continued investigation of virulence factors
mediating fungal infection of the eye.
The authors thank Denis M. O’Day for providing stocks of the VE175
and SC5314 strains of Candida albicans and Aaron P. Mitchell and
Michael C. Lorenz for providing the DAY286 and Tn7-rim13 fungal
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