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1.
The inhibitory effect of 30 plant oils was evaluated against biofilm forming Candida albicans strain (CA I) isolated from clinical samples, which was sensitive to 4 μg/ml of fluconazole, used as a positive control.
The standard strain (MTCC 227, CA II) used in this study was found to be highly resistant to fluconazole, 3,000 μg/ml of which
was required to inhibit the growth of this strain partially, and complete inhibition could not be achieved. Eighteen among
the 30 plant oils tested were found to show anti-Candida activity by disc diffusion assay. Effective plant oils were assessed
using XTT (2, 3-bis [2-Methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay for biofilm quantification.
Four oils eucalyptus, peppermint, ginger grass and clove showed 80.87%, 74.16%, 40.46% and 28.57% biofilm reduction respectively.
Minimum inhibitory concentration (MIC) values were calculated using agar dilution assay. Scanning electron microscopic (SEM)
analysis further revealed reduction in C. albicans biofilm in response to effective oils. The substantial antifungal activity shown by these plant oils suggests their potential
against infections caused by C. albicans. 相似文献
2.
Inhibition on <Emphasis Type="Italic">Candida albicans</Emphasis> biofilm formation using divalent cation chelators (EDTA) 总被引:3,自引:0,他引:3
Candida albicans can readily form biofilms on both inanimate and biological surfaces. In this study we investigated a means of inhibiting
biofilm formation using EDTA (Ethylenediaminetetra-acetic acid), a divalent cation chelating agent, which has been shown to
affect C. albicans filamentation. Candida albicans biofilms were formed in 96-well microtitre plates. Cells were allowed to adhere for 1, 2, and 4 h at 37°C, washed in PBS,
and then treated with different concentrations of EDTA (0, 2.5, 25, and 250 mM). EDTA was also added to the standardized suspension
prior to adding to the microtiter plate and to a preformed 24 h biofilm. All plates were then incubated at 37°C for an additional
24 h to allow for biofilm formation. The extent and characteristics of biofilm formation were then microscopically assessed
and with a semi-quantitative colorimetric technique based on the use of an XTT-reduction assay. Northern blot analysis of
the hyphal wall protein (HWP1) expression was also monitored in planktonic and biofilm cells treated with EDTA. Microscopic analysis and colorimetric readings
revealed that filamentation and biofilm formation were inhibited by EDTA in a concentration dependant manner. However, preformed
biofilms were minimally affected by EDTA (maximum of 31% reduction at 250 mM). The HWP1 gene expression was reduced in EDTA-treated planktonic and biofilm samples. These results indicate that EDTA inhibits C. albicans biofilm formation are most likely through its inhibitory effect on filamentation and indicates the potential therapeutic
effects of EDTA. This compound may serve a non-toxic means of preventing biofilm formation on infections with a C. albicans biofilm etiology. 相似文献
3.
The genotypes of 221 recent isolates of Candida albicans from various clinical specimens of 213 patients admitted to the University Malaya Medical Centre, Malaysia was determined based on the amplification of a transposable intron region in the 25 S rRNA gene. The analyses of 178 C. albicansisolated from nonsterile clinical specimens showed that they could be classified into three genotypes: genotype A (138 isolates), genotype B (38 isolates) and genotype C (2 isolates). The genotyping of 43 clinical isolates from sterile specimens showed that they belonged to genotype A (29 isolates), genotype B (10 isolates), genotype C (2 isolates) and genotype D (2 isolates). The overall distribution of C. albicans genotypes in sterile and nonsterile specimens appeared similar, with genotype A being the most predominant type. This study reported the identification of C. dubliniensis (genotype D) in 2 HIV-negative patients with systemic candidiasis, which were missed by the routine mycological procedure. The study demonstrated the genetic diversity of clinical isolates of C. albicans in Malaysia. 相似文献
4.
Flower-visiting beetles belonging to three species of Cetoniidae were collected on three mountains near Beijing, China, and yeasts were isolated from the gut of the insects collected. Based
on the 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequence analysis and phenotypic characterization,
four novel anamorphic yeast species located in the Candida albicans/Lodderomyces elongisporus clade were identified from 18 of the strains isolated. The new species and type strains are designated as Candida blackwellae AS 2.3639T (=CBS 10843T), Candida jiufengensis AS 2.3688T (=CBS 10846T), Candida oxycetoniae AS 2.3656T (=CBS 10844T), and Candida pseudojiufengensis AS 2.3693T (=CBS 10847T). C. blackwellae sp. nov. was basal to the branch formed by C. albicans and C. dubliniensis with moderately strong bootstrap support. The closest relative of C. oxycetoniae was L. elongisporus. C. jiufengensis sp. nov. and C. pseudojiufengensis sp. nov. were closely related with each other and formed a branch in a subclade represented by C. parapsilosis and L. elongisporus. 相似文献
5.
The aim of this study was to characterize switch phenotypes in Candida albicans biofilms. Cells of Candida albicans 192887g biofilms (24 h) were resuspended and these together with their planktonic counterparts were separately inoculated
on Lee’s medium agar supplemented with arginine and zinc, at 25 °C for 9 days, for colony formation. The different switch
phenotypes, as reflected by varying colony morphologies, were then examined for their (i) stability under various growth conditions,
(ii) carbohydrate assimilation profiles, (iii) susceptibility to the polyene antifungal, nystatin, (iv) adhering and biofilm-forming
ability, (v) filamentation, and (vi) growth rate in yeast nitrogen base medium supplemented with 100 mM glucose. Our data
showed that the frequency of phenotypic switching in C. albicans biofilms was approximately 1%. Compared with the planktonic yeasts, cells derived from candidal biofilms generated one of
the phenotypes less frequently (Chi-square-tests: P = 0.017). The five phenotypes derived from the biofilm growth demonstrated differing profiles for carbohydrate assimilation,
adhesion, biofilm formation, filamentation, and growth rate. These findings reported here, for the first time, imply that
phenotypic switching in the candidal biofilms differs from that in the planktonic growth, and affects multiple biological
attributes. 相似文献
6.
The aim of the present work was to observe microbial decolorization and biodegradation of the Direct Violet 51 azo dye by
Candida albicans isolated from industrial effluents and study the metabolites formed after degradation. C. albicans was used in the removal of the dye in order to further biosorption and biodegradation at different pH values in aqueous solutions.
A comparative study of biodegradation analysis was carried out using UV–vis and FTIR spectroscopy, which revealed significant
changes in peak positions when compared to the dye spectrum. Theses changes in dye structure appeared after 72 h at pH 2.50;
after 240 h at pH 4.50; and after 280 h at pH 6.50, indicating the different by-products formed during the biodegradation
process. Hence, the yeast C. albicans was able to remove the color substance, demonstrating a potential enzymatic capacity to modify the chemical structure of
pigments found in industrial effluents. 相似文献
7.
Guoying Wang Jianping Wen Hongmei Li Chunsheng Qiu 《Journal of industrial microbiology & biotechnology》2009,36(6):809-814
Strain Candida albicans PDY-07 was used to study the anaerobic biodegradation of phenol and m-cresol as single and dual substrates in batch cultures. The strain had a higher potential to degrade phenol than m-cresol. The cell growth kinetics of batch cultures with various initial m-cresol concentrations was investigated, and the Haldane kinetic model adequately described the dynamic behavior of cell growth
on m-cresol. When cells grew on the mixture of phenol and m-cresol, substrate interactions were observed. Phenol inhibited the utilization of m-cresol; on the other hand, m-cresol also inhibited the degradation of phenol. However, the presence of low-concentration phenol enhanced m-cresol biodegradation; 100 mg/l m-cresol could be completely degraded within a shorter period of time than m-cresol alone in the presence of 150–300 mg/l phenol. The maximum m-cresol biodegradation rate was obtained at the existence of 200 mg/l phenol. Phenol was preferably utilized by the strain
as a carbon and energy source. In addition, a sum kinetics model was used to describe the cell growth behavior in binary mixture
of phenol and m-cresol, and the interaction parameters were determined. The model adequately predicted the growth kinetics and the interaction
between the substrates. 相似文献
8.
In vitro activity of eugenol against <Emphasis Type="Italic">Candida albicans</Emphasis> biofilms 总被引:6,自引:0,他引:6
Most manifestations of candidiasis are associated with biofilm formation occurring on the surfaces of host tissues and medical
devices. Candida albicans is the most frequently isolated causative pathogen of candidiasis, and the biofilms display significantly increased levels
of resistance to the conventional antifungal agents. Eugenol, the major phenolic component of clove essential oil, possesses
potent antifungal activity. The aim of this study was to investigate the effects of eugenol on preformed biofilms, adherent
cells, subsequent biofilm formation and cell morphogenesis of C. albicans. Eugenol displayed in vitro activity against C. albicans cells within biofilms, when MIC50 for sessile cells was 500 mg/L. C. albicans adherent cell populations (after 0, 1, 2 and 4 h of adherence) were treated with various concentrations of eugenol (0, 20,
200 and 2,000 mg/L). The extent of subsequent biofilm formation were then assessed with the tetrazolium salt reduction assay.
Effect of eugenol on morphogenesis of C. albicans cells was observed by scanning electron microscopy (SEM). The results indicated that the effect of eugenol on adherent cells
and subsequent biofilm formation was dependent on the initial adherence time and the concentration of this compound, and that
eugenol can inhibit filamentous growth of C. albicans cells. In addition, using human erythrocytes, eugenol showed low hemolytic activity. These results indicated that eugenol
displayed potent activity against C. albicans biofilms in vitro with low cytotoxicity and therefore has potential therapeutic implication for biofilm-associated candidal infections. 相似文献
9.
Takagi Y Akada R Kumagai H Yamamoto K Tamaki H 《Applied microbiology and biotechnology》2008,77(5):1073-1082
Candida albicans is a human fungal pathogen and has been extensively studied because of its clinical importance. Comprehensive gene analyses
have, however, made little progress. This is because of the diploid and asexual characteristics of the fungus that hamper
gene disruptions. In this study, we found that ultraviolet (UV) irradiation, as well as mutagen treatment, strongly stimulated
loss of heterozygosity (LOH) in strains harboring artificially constructed heterozygosity. UV-induced LOH occurred more frequently
in cells within the logarithmic phase of growth compared to those within the stationary phase of growth. This was observed
at all loci tested on chromosome 7, except for a locus neighboring the centromere. C. albicans RAD52, whose orthologue in Saccharomyces cerevisiae was reported to be involved in DNA repair by homologous recombination, was shown to be required for UV-induced LOH. These
results suggest that high efficiency LOH caused by UV irradiation could be a prominent tool for gene analyses in C. albicans. 相似文献
10.
11.
We demonstrate here the regulatory role of cAMP in cell cycle of Candida albicans. cAMP was found to be a positive signal for growth and morphogenesis. Phosphodiesterase inhibitor aminophylline exhibited
significant effects, i.e., increased growth, as well as induced morphogenesis. Atropine and trifluoperazine negatively regulated
(inhibited) growth and did not induce morphogenesis. These changes were attributed to increase in cAMP levels and protein
kinase A (PKA) activity in presence of aminophylline, while reduction was observed in atropine and trifluoperazine (TFP) grown
cells. Alteration in cAMP signaling pathway affected the cell cycle progression in Candida albicans. Increased cAMP levels in aminophylline grown cells reduced the duration of cell cycle by inciting the cell cycle-specific
expression of G1 cyclins (CLN1 and CLN2). However atropine and trifluoperazine delayed the expression of G1 cyclins and hence prolonged the cell cycle. Implication
of cAMP signaling pathway in both the cell cycle and morphogenesis further opened the channels to explore the potential of
this pathway to serve as a target for development of new antifungal drugs. 相似文献
12.
13.
Vulvovaginal candidiasis is associated with the production of germ tubes by <Emphasis Type="Italic">Candida albicans</Emphasis> 总被引:1,自引:0,他引:1
Consolaro ME Albertoni TA Svidzinski AE Peralta RM Svidzinski TI 《Mycopathologia》2005,159(4):501-507
Twenty Candida albicans strains isolated from women attended at the Teaching and Research in the Laboratory of Teaching and Research in Clinical Analysis of the State University of Maringa, Paraná, Brazil, have been analyzed. Yeasts were identified by classical methods and patients subdivided into asymptomatic, vulvovaginal candidiasis(VVC) and recurrent vulvovaginal candidiasis (RVVC) groups. Yeasts were incubated in RPMI + fetal calf serum to analyze germ tubes every two hours, up to 10 h. In vitro sensitivity to fluconazole, itraconazole, ketoconazole, amphotericin B and nystatin was analyzed according to NCCLS-M27-A microdilution assay. Yeast isolated from symptomatic women produced significantly more germ tubes than asymptomatic women (P < 0.05). However, no significant difference between yeasts from VVC and RVVC occurred (P > 0.05). Variation between MIC50 and MIC90 of tested antifungal agents was slight among isolated yeasts, while no resistant yeasts were detected. Nevertheless, VVC yeasts were more DDS (reduced dose-dependent susceptibility) for nystatin and RVVC were more DDS for ketoconazole. Results suggest that colonization by yeast in the vagina and lack of symptoms may be partially explained by the yeast’s sparse capacity to form germ tubes, On the other hand, RVVC was not associated with antimicrobial resistance. DDS high frequency for nystatin and ketoconazole indicates that identification, and susceptibility of antifungals tests are important to management of VVC. 相似文献
14.
W. J. Kong J. B. Wang C. Jin Y. L. Zhao C. M. Dai X. H. Xiao Z. L. Li 《Applied microbiology and biotechnology》2009,83(6):1183-1190
Using the 3114/3115 thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, the heat output of Candida albicans growth at 37°C was measured, and the effect of emodin on C. albicans growth was evaluated by microcalorimetry coupled with chemometric methods. The similarities between the heat flow power (HFP)–time
curves of C. albicans growth affected by different concentrations of emodin were calculated by similarity analysis (SA). In the correspondence
analysis (CA) diagram of eight quantitative parameters taken from the HFP–time curves, it could be deduced that emodin had
definite dose-effect relationship as the distance between different concentrations of it increased along with the dosage and
the effect. From the principal component analysis (PCA) on eight quantitative parameters, the action of emodin on C. albicans growth could be easily evaluated by analyzing the change of values of the main two parameters, growth rate constant k
2 and maximum power output . The coherent results of SA, CA, and PCA showed that emodin at different concentrations had different effects on C. albicans growth metabolism: A low concentration (0–10 μg ml−1) poorly inhibited the growth of C. albicans, and a high concentration (15–35 μg ml−1) could notably inhibit growth of this fungus. This work provided a useful idea of the combination of microcalorimetry and
chemometric analysis for investigating the effect of drug and other compounds on microbes. 相似文献
15.
Michela Isola Raffaella Isola Maria Serenella Lantini Alessandro Riva 《Journal of microbiology (Seoul, Korea)》2009,47(3):260-264
The fine structure of Candida albicans has been repeatedly described by transmission electron microscopy, whereas studies by high-resolution scanning electron microscopy
(HRSEM) are rare and devoted solely to the study of its external morphology. This report describes the results of an HRSEM
study on C. albicans carried out by an osmium maceration protocol modified to better retain the structural characteristics of this yeast. Thus,
we visualized various intracellular structures including invaginations of cell membrane (plasmalemmasomes), nuclear envelope,
mitochondria, the vacuolar system, and two additional structures that might represent a form of endoplasmic reticulum and
the Golgi apparatus. The present investigation, which for the first time shows the organelles of C. albicans at the 3D level, may lead to a better understanding of its cell physiology. 相似文献
16.
17.
Candida albicans biofilms on most medical devices are exposed to a flow of body fluids that provide water and nutrients to the fungal cells.
While C. albicans biofilms grown in vitro under static conditions have been exhaustively studied, the same is not true for biofilms developed
under continuous flow of replenishing nutrients. Here, we describe a simple flow biofilm (FB) model that can be built easily
with materials commonly available in most microbiological laboratories. We demonstrate that C. albicans biofilms formed using this flow system show increased architectural complexity compared to biofilms grown under static conditions.
C. albicans biofilms under continuous medium flow grow rapidly, and by 8 h show characteristics similar to 24 h statically grown biofilms.
Biomass measurements and microscopic observations further revealed that after 24 h of incubation, FB was more than twofold
thicker than biofilms grown under static conditions. Microscopic analyses revealed that the surface of these biofilms was
extremely compact and wrinkled, unlike the open hyphal layer typically seen in 24 h static biofilms. Results of antifungal
drug susceptibility tests showed that C. albicans cells in FB exhibited increased resistance to most clinically used antifungal agents. 相似文献
18.
Anaerobic biodegradation of phenol by <Emphasis Type="Italic">Candida albicans</Emphasis> PDY-07 in the presence of 4-chlorophenol 总被引:1,自引:0,他引:1
Guoying Wang Jianping Wen Guanghai Yu Hongmei Li 《World journal of microbiology & biotechnology》2008,24(11):2685-2691
Biodegradation of phenol and 4-chlorophenol (4-cp) using pure culture of Candida albicans PDY-07 under anaerobic condition was studied. The results showed that the strain could completely degrade up to 1,800 mg/l
phenol within 68 h. The capacity of the strain to degrade phenol was higher than that to degrade 4-cp. In the dual-substrate
system, 4-cp intensely inhibited phenol biodegradation. Comparatively, low-concentration phenol from 25 to 150 mg/l supplied
a carbon and energy source for Candida albicans PDY-07 in the early phase of biodegradation and accelerated the assimilation of 4-cp, which resulted in that 50 mg/l 4-cp
was degraded within less time than that without phenol. While the biodegradation of 50 mg/l 4-cp was inhibited in the presence
of 200 mg/l phenol. In addition, the intrinsic kinetics of cell growth and substrate degradation were investigated with phenol
and 4-cp as single and dual substrates in batch cultures. The results demonstrated that the models adequately described the
dynamic behaviors of biodegradation by Candida albicans PDY-07. 相似文献
19.
The present study involves collecting 125 isolates labeled as C. albicans from five different Lebanese hospitals and utilizing the microsatellite genotyping test to determine the following: first,
the accuracy of hospital identification by comparing microsatellite results to hospital results. Second, the frequency and
genotypes of infectious strains present relative to tissue and hospital location- a possible indicator of nosocomial infection,
and third, a possible relationship between lack of microsatellite heterozygosity to azole resistance. Our results showed that
the error in hospital identification varied from 2 to 33%, averaging at 7%, with the highest identification error in stool.
Misidentified isolates were mainly Candida tropicalis followed by C. glabrata and C. parapsilosis. Strains with similar genotypes were also found to occur within certain hospitals suggesting the possibility of nosocomial
infection. Finally, a relationship between lack of heterozygosity and azole resistance was observed since nine out of 10 homozygous
isolates sharing a common allele with a heterozygote strain were sensitive to all drugs tested, whereas the homozygous genotype
was resistant to at least one drug. 相似文献
20.
A eukaryotic catechol 1,2-dioxygenase (1,2-CTD) was produced from a Candida albicans TL3 that possesses high tolerance for phenol and strong phenol degrading activity. The 1,2-CTD was purified via ammonium
sulfate precipitation, Sephadex G-75 gel filtration, and HiTrap Q Sepharose column chromatography. The enzyme was purified
to homogeneity and found to be a homodimer with a subunit molecular weight of 32,000. Each subunit contained one iron. The
optimal temperature and pH were 25°C and 8.0, respectively. Substrate analysis showed that the purified enzyme was a type
I catechol 1,2-dioxygenase. This is the first time that a 1,2-CTD from a eukaryote (Candida albicans) has been characterized. Peptide sequencing on fragments of 1,2-CTD by Edman degradation and MALDI-TOF/TOF mass analyses
provided information of amino acid sequences for BLAST analysis, the outcome of the BLAST revealed that this eukaryotic 1,2-CTD
has high identity with a hypothetical protein, CaO19_12036, from Candida albicans SC5314. We conclude that the hypothetical protein is 1,2-CTD. 相似文献