For direct identification of Candida albicans from other Candida species, the chlamydospore formation and the mycelial transition induced by high temperature and by sera were examined in 198 Candida isolates. The germ tubes of C. albicans developed early at 30 min in high temperature-induction, but at 60 min in serum-induction. C. albicans generated germ tubes well at concentrations lower than 2 x 10(7) cells/ml, but the germ tube formation was markedly restrained at concentrations higher than 4 x 10(7) cells/ml. In a serum-free, yeast extract-peptone-dextrose (YEPD) medium, C. albicans grew as a yeast form at 30 degrees C and as a mycelial form at 35-42 degrees C. Mycelial development was maximal at 37 degrees C in serum and at 39 degrees C in YEPD. Germ tubes were formed within 30 min in YEPD at 39 degrees C, but after 60 min in serum at 37 degrees C. Our examination showed that the 39 degrees C-induced germ tube formation tests were very reliable (sensitivity 100%, specificity 100%) at discerning C. albicans from other Candida species. These results suggest that the high temperature-induced germ tube formation testing could be a useful identification method of C. albicans in clinical laboratories.
Candida albicans/physiology ; Candida albicans/isolation & purification* ; Sensitivity and Specificity ; Temperature

OBJECTIVETo explore the influence of Candida albicans (Ca) on the motility and ultrastructure of human spermatozoa and its possible mechanism.

METHODSSemen samples obtained from 10 healthy volunteers by masturbation were prepared by the swim-up technique and sperm density to 40 x 10(6)/ml. The samples were then inoculated at 37 degrees C with different concentrations of a uropathogenic strain of Ca isolated from an outpatient, with initial fungi/spermatozoa ratios varying among 1:1 (Group A), 1:10 (Group B), 1:100 (Group C), 1:1000(Group D), and 1:10,000 (Group E). And Group F containing Ham's F-10 only was found as the negative control. Motion parameters were analysed by computer-aided sperm analyzer (CASA) at 0 hour, 1 hour, 2 hours and 4 hours respectively. Modalities of spermatozoa and possible adherence and/or agglutination were observed under the light microscope. Finally, all the samples were studied by transmission electron microscopy.

RESULTSDistinct adhesion of spermatozoa to Ca and agglutination were noticed. In all the motion parameters, progressive motility was affected most and dependent upon incubation time and bacterial concentration. Progressive motility showed a significant difference between Group A and the control (P < 0.01). With the prolongation of incubation time, other parameters were showing more and more differences. Analysis by electron microscopy revealed multiple ultrastructural damages.

CONCLUSIONCa significantly inhibits human sperm motility and decreases sperm viability in vitro. Its mechanism is possibly related to Ca's adhesion to human spermatozoa and the impairment inflicted by Ca to sperm ultrastructure.

Candida albicans ; isolation & purification ; physiology ; Candidiasis, Vulvovaginal ; microbiology ; Female ; Humans ; In Vitro Techniques ; Male ; Sperm Motility ; Spermatozoa ; physiology ; ultrastructure

OBJECTIVETo investigate the effects of gallic acid against Candida albicans biofilms in vitro.

METHODXTT reduction assay was performed to determine the effect of gallic acid on C. albicans biofilms and its adherence, and microscopic examination was conducted to assess the effect of gallic acid on morphogenesis of C. albicans biofilms; and cytotoxic assay was used to measure the adverse effects of gallic acid.

RESULTSMIC50, SMIC50 of gallic acid against C. albicans biofilms were 500, 1000 mg x L(-1), respectively; 100 mg x L(-1) and 1000 mg x L(-1) of gallic acid could inhibit the initial adherence and filamentous growth, and the agent showed poor cytotoxic activity.

CONCLUSIONgallic acid displayed potent activity against C. albicans biofilm.

Biofilms ; drug effects ; Candida albicans ; cytology ; drug effects ; physiology ; Cell Adhesion ; drug effects ; Dose-Response Relationship, Drug ; Gallic Acid ; pharmacology

OBJECTIVETo investigate the genotypic profiles of Candida albicans isolates from erosive oral lichen planus (OLP) and nonerosive OLP, and then to compare the results with their virulence attributes.

METHODSA total of 112 isolates from healthy control (26), erosive OLP (62) and nonerosive OLP (24) were screened for genotypic profiles by using the randomly amplified polymorphic DNA (RAPD) assay. In addition, adhesion to buccal epithelial cells assay and phospholipase activity assay were used to evaluate the virulence attributes of these isolates.

RESULTSRAPD analyses with some random primer revealed 4 different genotypes among all isolates, and there was significant difference in the geneotypic constitution between every two groups. Statistically, in healthy group the major type was B and D, however, the major type in erosive OLP was A and C, and the major type in nonerosive OLP was A and D. The isolates with genotype A had the strongest adherence among 4 genotypes. The phospholipase activity of the isolates with genotype A and C were higher than that with genotype B and D.

CONCLUSIONSSome Candida albicans isolates with special genotypic profiles and virulence attributes may contribute to the development and progression of OLP.

Adhesiveness ; Candida albicans ; classification ; enzymology ; physiology ; Genotype ; Humans ; Lichen Planus, Oral ; microbiology ; Phospholipases ; metabolism ; Random Amplified Polymorphic DNA Technique

Candida albicans produced a karatinolytic proteinase (KPase) or C. albicans producing proteinase (CAPP), a proposed new term for this enzyme, and Trichophyton mentagrophytes also produced KPase when cultivated in liquid medium containing human stratum corneum (HSC) as the nitrogen source, but were unable to do so when cultivated in sabouraud dextrose broth. Purified KPase from the culture supernatants of C. albicans had a molecular weight of 42,000 and an optimum pH at 4.0. The KPase was found to belong to the carboxyl proteinases group and its activity was strongly inhibited by pepstatin. Both fungi were able to grow by secreting KPase which digested HSC for nutrients. KPase from both fungi had high activity in each optimum pH, such as weakly acidic pH on C. albicans and neutral pH on T. mentagrophytes to adapt their surrounding environment by changing the environmental pH into their own optimum pH.
Candida albicans/*enzymology/growth & development ; Culture Media ; Endopeptidases/*physiology ; Hydrogen-Ion Concentration ; Molecular Weight ; Trichophyton/*enzymology/growth & development

In Candida albicans, adaptation to environmental pH is relevant to its pathogenicity. Calcium signaling pathway involves in many stress responses and often accompany with Ca2+ fluctuation. We constructed CCH1 and MID1 mutant strains and studied their effect on calcium influx and further investigated the regulation by Crz1p transcription factor. We used PCR-directed gene disruption to construct cch1delta/delta and mid1delta/delta null mutant. By using a flow cytometry-based method we monitored the free cytosolic Ca2+ levels under alkaline stress. Moreover, we constructed pPHO89-LacZ plasmids and by beta-Galactosidase assays, we analyzed the changes of LacZ activities after gene disruption. The results showed that alkaline stress induced calcium burst reduced obviously in cch1delta/delta and mid1delta/delta mutant strains, also for LacZ activities, and fully abolished in crz1delta/delta mutant strain. Finally, by realtime PCR, we confirmed the regulation role of Crz1p in CCH1 and MID1 genes but in a calcineurin independent way. Studies on the effect of calcium pathway on response to alkaline stress will provide an important theoretical basis for Candida albicans infection-oriented treatment and new drug targets.
Calcium Channels ; metabolism ; Candida albicans ; genetics ; metabolism ; physiology ; Fungal Proteins ; genetics ; physiology ; Gene Expression Regulation, Fungal ; Hydrogen-Ion Concentration ; Signal Transduction ; Stress, Physiological ; Transcription Factors ; metabolism ; physiology

Candida albicans exhibits the ability to grow in either a yeast or a mycelia form in response to different environmental factors. The mycelia form, found in infected tissues, is important as a virulence factor in the adherence of the organism to the host epithelium. In vitro, the morphological transition can be induced by environmental shifts in the growing conditions, or by a variety of exogenous factors, including ambient pH, nutritional status and temperature. The differential-display reverse transcription polymerase chain reaction (DDRT-PCR) is a powerful technique for comparing gene expression between cell types, stages of development or differentiation. Hyphae related genes were identified and characterized using a PCR-based differential display. Candida albicans formed a germ tube when cultured in rabbit serum, RPMI 1640 medium or 39degrees C-YPD medium. We gained 21 cDNA bands showing a different expression pattern from that of the uninduced culture. DNA was extracted from the same location of the isolated bands, and PCR was performed under the same conditions, which reamplified the PCR product, showing the specific expression patterns according to the culture conditions. We cloned 18 germ tube-related cDNA clones (inserts average size is 80 - 700 bp) and sequenced them. The nucleotide sequences of the 18 clones were identified through in the present study from GenBank, and were found to have the accession number (AF405213-AF405230). We could not find any nucleotide sequence having a high homology with these clones. This study could form a part of the projects in the search for genes related to the germ tube formation of C. albicans.
Animals ; Base Sequence/genetics ; Candida albicans/genetics/*physiology ; Cloning, Molecular ; DNA, Complementary/genetics ; Molecular Sequence Data ; Rabbits ; Reverse Transcriptase Polymerase Chain Reaction/*methods ; Support, Non-U.S. Gov't

OBJECTIVETo explore the molecular mechanism of the differences in biofilm formation abilities of Candida albicans isolated from the respiratory tract.

METHODSThe biofilms formed by Candida albicans isolates from the respiratory tract and the standard strain ATCC90028 were examined for bacterial proliferation using XTT reduction assay. The mRNA expression of CPH1, EFG1, ALS3 and HWP1 in the isolates were measured with fluorescent quantitative RT-PCR.

RESULTSXTT reduction assay demonstrated a strong ability of biofilm formation in 8 clinical isolates, and a relatively low biofilm formation ability in 7 clinical isolates and ATCC90028 strain. The strong and weak biofilm formers showed significant differences in ALS3 and HWP1 mRNA expressions (P<0.05) but not in EFG1 or CPH1 mRNA expressions (P>0.05).

CONCLUSIONThe clinical isolates from the respiratory tract have different biofilm formation abilities under regulation by genes other than the transcription factors CPH1 and EFG1.

Biofilms ; Candida albicans ; classification ; genetics ; physiology ; DNA-Binding Proteins ; metabolism ; Exons ; Fungal Proteins ; metabolism ; Humans ; Membrane Glycoproteins ; metabolism ; Phenotype ; Respiratory System ; microbiology ; Transcription Factors ; metabolism

OBJECTIVETo investigate the effect of andrographolide derivative Yanhuning (YHN) on Candida albicans biofilms in rats.

METHODThe rat C. albicans biofilms subcutaneous catheter model was established by intraperitoneally injecting YHN (40, 20, 10, 5, 2.5 mg x kg (-1)), with the FLC (80 mg x kg(-1)) positive group as the control group. After 7 d, CFU counting and XTT assay were used to evaluate the effect of YHN on C. albicans biofllms in vivo. Scanning electron microscopy (SEM) was applied to observe the morphological changes in rat biofilms intervened by YHN. The real-time fluorescence quantification PCR was adopted to detect expressions of C. albicans adhesion-related genes, such as ALS1, ALS3, HWP1, EAP1 and MP65.

RESULTThe YHN group showed much less CFUs on catheter pieces and lower XTT metabolic activity than the blank group, with dosage dependence. SEM also showed that YHN could obviously decrease C. albicans adhesion on subcutaneous catheters in rats. According to qRT-PCR's results, YHN can down-regulate expressions of ALS1, ALS3, HWP1, EAP1 and MP65.

CONCLUSIONYHN could inhibit C. albicans biofilms in rats.

Animals ; Biofilms ; drug effects ; growth & development ; Candida albicans ; cytology ; drug effects ; physiology ; Catheters ; microbiology ; Cell Adhesion ; drug effects ; Diterpenes ; chemistry ; pharmacology ; Dose-Response Relationship, Drug ; Rats

OBJECTIVETo detect the effect of andrographolide on apoptosis of Candida albicans biofilm dispersion cells.

METHODThe morphological changes of apoptotic C. albicans biofilm cells were observed by using Hoechst 33258 staining Fluorescence microscope; changes of mitochondrial membrane potential (MMP) of C. albicans biofilm cells were detected by rhodamine 123 staining flow cytometry; and reactive oxygen species (ROS) was detected by DHR staining flow cytometry.

RESULT1 000, 100 micromol x L(-1) of andrographolide could cause pyknosis and dense staining of C. albicans biofilm cells, 1 000, 100, 10 micromol x L(-1) of andrographolide could decrease MMP and increase ROS of C. albicans biofilm cells.

CONCLUSIONAndrographolide of appropriate concentrations could induce apoptosis of dispersion cells of C. albicans biofilms.

Antifungal Agents ; pharmacology ; Apoptosis ; drug effects ; Biofilms ; Candida albicans ; drug effects ; physiology ; Diterpenes ; pharmacology ; Membrane Potential, Mitochondrial ; drug effects ; Reactive Oxygen Species ; metabolism