Enterogenous infection of Candida albicans in immunocompromised rats under severe acute pancreatitis

BACKGROUND:Opportunistic infection of Candida albicans(C.albicans) has become a serious problem in immunocompromised patients.The study aimed to explore the mechanism of enterogenous infection of C.albicans in immunocompromised rats under severe acute pancreatitis(SAP).METHODS:Sprague Dawley(SD) rats(n=100) were randomly assigned into 5 groups as the following:blank group,cyclophosphamide+ceftriaxone+SAP group,cyclophosphamide+ceftriaxone group,cyclophosphamide+SAP group,and cyclophosphamide group.The rats were sacrificed at 5and 10 days,and their jejunum,colon,mesenteric lymph nodes,pancreas,intestinal content,and blood were quickly collected to detect C.albicans.A region of the 25 S rRNA gene was chosen and amplified by polymerase chain reaction(PCR) to differentiate C.albicans genotypes.The amplified products were further sequenced and compared to judge their homology.RESULTS:Compared with the Cyclophosphamide group,the combination of immunosuppressants and broad-spectrum antibiotics significantly increased the colonization of C.albicans in intestine in 5 and 10 days.Pure SAP stress did not increase the opportunistic infection of C.albicans.The PCR products of C.albicans isolates all belonged to the genotype A family,and sequence alignment showed that the amplified fragments were homologous.CONCLUSION:The damage of immune system and broad-spectrum antimicrobial agents are important risk factors for opportunistic fungal infection.Intestinal tract is an important source for genotype-A C.albicans to translocate and invade into bloodstream.

Study of the prevalence and association of ocular chlamydial conjunctivitis in women with genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans attending outpatient clinic

AIMTo determine the association between chlamydial conjunctivitis and genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans, in addition to the possible relationship between cultured bacterial pathogens and oculogenital chlamydial infection.METHODSThis study was performed on 100 (50 symptomatic and 50 asymptomatic) women attending the Gynecological and Obstetric outpatient clinic of Alzahra hospital, Alazhar University. Simultaneously a conjunctival swab was taken from these patients. Polymerase chain reaction (PCR) was done on DNA extracted from both vaginal and conjunctival swab samples. Culture for both vaginal and conjunctival swabs was also done.RESULTSCandida albicans was the predominant organism isolated by culture in 20% and 40% of conjunctival and vaginal swabs respectively. By the PCR method, ocular Chlamydia trachomatis was present in 60% of symptomatic women, while genital Chlamydia trachomatis infection was present in 30% of symptomatic women. The results of this method also indicated that 25/50 (50%) vaginal swabs were positive with PCR for Candida albicans versus 15/50 (30%) were PCR positive in conjunctival swab. Mycoplasma genitalium was present in only 10% of vaginal swabs. Concomitant oculogenital PCR positive results for Chlamydia trachomatis and Candida albicans were 30% and 28% respectively.CONCLUSIONOcular Chlamydia trachomatis was associated with genital Chlamydia trachomatis in a high percentage of women followed by Candida albicans. Cultured bacterial organisms do not play a role in enhancement of Chlamydia trachomatis infection.

Fluconazole Susceptibility and Genotypic Heterogeneity of Oral Candida albicans Colonies from the Patients with Cancer Receiving Chemotherapy in China

Aim To identify heterogeneity of Candida albicans （C. albicans） isolated from the population with cancer in China by using identification medium, subculture molecular typing, and antifungal susceptibility test. Methodology Oral cheek mucosal specimens from 52 cancer patients receiving chemotherapy were cultured on CHROMagar CandidaTM plates for Candida identification. All the C. albicans colonies on the plates were subcultured and reconfirmed by API20C, then submitted to the antifimgal drug susceptibility test with fluconazole and molecular typing using randomly amplified polymorphic DNA-PCR （RAPD） with primers RSD6 and RSD12.Results 54% （28/52） patients were oral yeast carriage in which C. albicans predominated. More than 7 C. albicans colonies were isolated from each of 12 patients （Group A）, while less than 5 colonies were isolated from each of 16 patients （Group B）. RSD6 and RSD12 were successful in eliciting 17 （A1-A17） and 2 （B1-B2） genotypes, respectively from among the 205 isolates. The two primers were combined to generate 21 genotypes. The C. albicans isolates obtained from the same patient and episode showed a diversity for fluconazole revealed by MIC50 and MIC90. Conclusion The heterogeneity of the C. albicans colonies isolated from the same patients can be detected. C. albicans with varied fluconazole susceptibility and genotypic characteristics may coexist in the same oral Candida population.

Comparison of the Effects of Three Different Anti-fungus Drugs on Candida Albicans of Murine Vaginal Mucosa

To compare the therapeutic effects of three different anti-fungal drugs （i.e., terbinafine, fluconazole and intraconazole） in the treatment of experimental vaginitis caused by Candida albicans （C. albicans） in mice, the fungal vaginitis model was established in female ICR mice by intravaginal inoculation of suspension of C. albicans after the animal had been pretreated with estradiol. Mice were divided at random into different groups and then respectively treated with terbinafine, fluconazole and intraconazole given by gastrogavage. The burden of the fungus in the vaginal lavage fluids in the mice of the different groups was measured dynamically at different time points after the beginning of the drug treatment. The fungal burdens in the vaginal lavage fluids taken at different time points from the mice treated with terbinafine were significantly higher than those taken at corresponding time points from mice treated with fluconazole or itraconazole （P〈0.01）. The fungal burdens in the vaginal lavage fluids taken from mice 1 week after the beginning of the treatment with terbinafine remained at a relatively high level. A dramatic drop in the fungal burden was noted in the vaginal lavage fluids taken on the 2nd day of the treatment from mice treated with itraconazole or fluconazole group and the fungal burden on the 3rd day of the treatment in these mice were at a very low level, suggesting that fluconazole or itraconazole were highly effective for the treatment. However, the difference in the therapeutic effect between the two drugs was not significant （P〉0.05）. Itraconazole or fluconazole, but not terbinafine, is very effective for the treatment of fungal vaginitis caused by C. albicans in mice.

Study of Candida Albicans Vaginitis Model in Kunming Mice

The model of vaginal candidiasis in Kunming mice was constructed in order to search for the optima construction conditions and provide an economic animal model of Candida albicans (C. albicans) vaginitis. Estrogen benzoate (E2) was given to mice at different concentrations ranging from 0.0 to 0.05 mg/mouse (4 levels) beginning 72 h prior to vaginal inoculation, then mice were in- oculated intravaginally with various concentrations of stationary-phase C. albicans blastoconidia (ATCC90028) (5 levels) in 20 μL of phosphate-buffered saline (PBS) in each E2 level. General state, scores of genital pathology, the hyphae and vaginal fungal burden (CFU) in vaginal lavage fluid, the hydrops rate of uterus and vaginal tissues for pathological section in mice were observed and ob- tained at day 2, 4, 7, 14 and 21 after inoculation. The results showed the infection rate in mice was related to the dosage of E2 and concentration of C. albicans blastoconidia. Additionally there was better cross-effect between the two treated factors. The infection rate was about 80% on the day 4, and could reach 100% on the day 7 until the end of experiment after inoculated intravaginally in groups of E2I3, E2 0.025 mg/mouse injected hypodermically and inoculated intravaginally with 5×104 C. albicans blastoconidia, and large amount of hyphae and blastoconidia could be observe in superfi- cial layer tissue and canal of vaginal by PAS. From the results in our experiment it was concluded that E2I3 was the optima construction condition in kunming mice.

Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C.albicans).Human single-rooted teeth contaminated with C.albicans were treated with calcium hydroxide,2%chlorhexidine gel, calcium hydroxide plus 2%chlorhexidine gel,or saline(0.9%sodium chloride) as a positive control.The samples obtained at depths of 0-100 and 100-200μm from the root canal system were analyzed for C.albicans load by counting the number of colony forming units and for the percentage of viable C.albicans using fluorescence microscopy.First,the antimicrobial activity of calcium hydroxide and the 2%chlorhexidine gel was evaluated by counting the number of colony forming units.After 14 days of intracanal medication,there was a significant decrease in the number of C.albicans colony forming units at a depth of 0-100μm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment.However,there were no differences in the number of colony forming units at the 100-200μm depth for any of the medications investigated.C.albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis.Antifungal activity against C.albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only.Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C.albicans.

Antifungal Activity of Schinifoline Against Candida Albicans in Caenorhabditis Elegans

Zanthoxylum schinifolium has been used as spices and traditional medicine in China for hundreds of years.A variety of active substances have been isolated from Zanthoxylum schinifolium using biological and chemical techniques.Among these substances,the effect of schinifoline has gradually attracted much attention.Candida albicans is one of the most common pathogens isolated from the gastrointestinal tract,vagina,and mouth in healthy individuals.In a healthy population,there are various mechanisms in host,such as the microbial flora,the epithelial barriers,and the innate immune system,that can control the presence of Candida albicans.However,when host immunity is compromised,an invasive fungal infection is more likely to occur.In this study,we explored the antifungal activity of schinifoline against Candida albicans in Caenorhabditis elegans.To determine the optimal concentration of schinifoline,we investigated the lifespan,defecation cycle and locomotion behavior of Caenorhabditis elegans after treatment with schinifoline.In addition,we examined colony formation in the intestine of Caenorhabditis elegans after Candida albicans infection.The results indicated that 100 and 200 mg/L of schinifoline could prolonged the lifespan,shorten the defecation cycle and increased the locomotion behavior of Caenorhabditis elegans,with 100 mg/L of schinifoline being the optimal concentration.Moreover,100 mg/L of schinifoline increased the lifespan of Caenorhabditis elegans after infection and inhibited the colony formation of Candida albicans in Caenorhabditis elegans intestine.Therefore,we concluded that schinifoline exhibits anti-fungal effects and its potential use as natural drugs should be further explored in future studies.

Expression of Candida Albicans Secreted Aspartyl Proteinase in Acute Vaginal Candidiasis

In order to analyze the in vivo expression of Candida albicans secreted aspartyl pro- teinases (SAP) in human vaginal infection, the vaginal secretion from 29 human subjects was col- lected by vaginal swab, and the expression of SAP1–SAP6 was detected by reverse-transcriptase po- lymerase chain reaction using specific primer sets. It was found that Sap2 and Sap5 were the most common genes expressed during infection; Sap3 and Sap4 were detected in all subjects and all 6 SAP genes were simultaneously expressed in some patients with vaginal candidiasis. It was suggested that the SAP family is expressed by Candida albicans during infection in human and that Candida albi- cans infection is associated with the differential expression of individual SAP genes which may be involved in the pathogenesis of vaginal candidiasis.

Origin of Candida albicans in Human Oral Cavity

Purpose: Candida albicans is regarded as a part of normal flora in the human oral cavity. However, it remains unclear whether the genus Candida, especially C. albicans, is an oral resident microorganism and causes marital infection or not. The purpose of the present study was to elucidate the origin of oral C. albicans by investigating the colonization and infection route to oral cavities of this organism with arbitrarily primed polymerase chain reaction (AP-PCR). Methods: After C. albicans was isolated from four subjects (average age: 42.2, range: 33 - 56), the isolations of this organism from them were performed six months later again. To investigate whether C. albicans is an oral resident microorganism, the genotype homology of each C. albicans isolates that were isolated twice from the same subjects was compared. Moreover, C. albicans was isolated from five pairs of married couples (average period of cohabitation: 12.4 years, range: 5 - 31). To investigate whether C. albicans causes marital infection, the genotype homology of C. albicans isolates that were isolated from each pair of married couples was compared. Results: AP-PCR patterns of C. albicans that were isolated from each subject at o month and after 6 months showed the identical genotypes among each individual. C. albicans isolates from five pairs of married couples showed the identical genotypes between a husband and wife of each pair on AP-PCR. Conclusion: These results indicated that C. albicans was an oral resident microorganism and caused the marital infection.

Identification of a Candida albicans Biofilm Inhibitor

Candida albicans proliferates in the skin and oral cavity and is the causative agent of candida dermatitis and oral candidiasis. C. albicans is known to form biofilms on oral mucosa and denture surfaces. Formation of biofilms deteriorates the permeability of antifungal drugs, decreasing their effectiveness. Therefore, in this study, I identified a compound with inhibitory activity against C. albicans biofilm formation. Heat shock protein 90 was selected as the target protein, and a potential ligand for the same was extracted and identified as 2-(4-methylpiperazin-1-yl)cyclopentanol. C. albicans was then cultured with varying concentrations of this compound: 0 mmol/L, 0.63 mmol/l. 2.5 mmol/l, and 10 mmol/l, and biofilm formation was measured via crystal violet assay. The findings demonstrated that 2-(4-methylpiperazin-1-yl)cyclopentanol substantially inhibits biofilm formation when added at a concentration of 0.63 mmol/l or higher. It is suggested that C. albicans could be eliminated more efficiently using this compound in combination with the existing antifungal drug miconazole. Further, the compound may also be useful as a disinfectant for medical devices, such as catheters, to prevent the formation of C. albicans biofilms.

Effects of Cinnamaldehyde, Ocimene, Camphene, Curcumin and Farnesene on Candida albicans

Efficacy of five plant molecules against thirty three clinical isolates and two standard strains of C. albicans, differentially susceptible to fluconazole (FLC) is tested in this study. Effect on biofilm (adhesion, development and maturation) formation, morphogenesis and synergy with fluconazole (FLC) against a FLC resistant strain of Candida albicans ATCC 10231 is also evaluated. All the plant molecules tested were equally effective against isolates and strains of C. albicans (N = 35) tested in this study. Cinnamaldehyde was found most effective against planktonic growth followed by ocimene. Both the molecules exhibited fungicidal activity and killed 99.9% of inoculum within 80 and 20 min of exposure respectively at 0.62 mM and 176.8 mM concentrations. Curcumin (5 - 20 mM), camphene (8 - 32 mM) and farnesene (25 - 100 mM), although inhibited planktonic growth, were fungistatic. All the five plant molecules tested in this study inhibited morphogenesis significantly and exhibited considerable activity against biofilm formation. Inhibition of biofilm was found to be stage specific i.e. efficacy was more against adhesion followed by developing and mature biofilm. Plant molecules tested exhibited excellent synergy with fluconazole. However FIC index values 0.155, 0.062 and 0.046 indicate that ocimene was the most effective synergistic molecule inhibited planktonic growth, developing biofilm and mature biofilm growth respectively at very low concentrations. This is the first report of anti-Candida activity of three terpenoids viz. ocimene, farnesene and camphene against planktonic & biofilm growth, morphogenesis as well as synergy with FLC. Plant molecules tested in this study may find use in antifungal chemotherapy individually and or in a combination with FLC.

SAP Expression in Candida albicans Strains Isolated from Mexican Patients with Vaginal Candidosis

To determine the frequency and expression of the ten SAP (secreted aspartyl protease) genes in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis, a group of 264 women (age 18 - 57 years) with vaginal infections, predisposed by diabetes mellitus or contraceptive consumption, were evaluated. C. albicans was identified using PCR to amplify the rRNA internal transcribed spacer regions ITS1 and ITS2. The presence of the SAP genes was determined using conventional PCR, and their expression levels were determined using real-time PCR after the C. albicans strains had been grown in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in the samples from 50 women (18.9%). The genotyping frequencies of the SAP genes were as follows: SAP1, 94%;SAP2, 98%;SAP3, 80%;SAP4, 100%;SAP5, 100%;SAP6, 100%;SAP7, 63%;SAP8, 96%;SAP9, 70%;and SAP10, 88%. The most frequently expressed genes in the strains harboring all of the genes were SAP1, 90%;SAP2, 90%;SAP3, 90%;SAP4, 100%;SAP5, 90%;SAP6, 90%;SAP7, 100%;SAP8, 90%;SAP9, 100%;and SAP10, 100%. SAP genes were expressed in the RHVE, suggesting that the Sap proteins play an important role in the pathogenesis of infection.

Atmospheric humidity regulates same-sex mating in Candida albicans through the trehalose and osmotic signaling pathways

Sexual reproduction is prevalent in eukaryotic organisms and plays a critical role in the evolution of new traits and in the generation of genetic diversity.Environmental factors often have a direct impact on the occurrence and frequency of sexual reproduction in fungi.The regulatory effects of atmospheric relative humidity(RH)on sexual reproduction and pathogenesis in plant fungal pathogens and in soil fungi have been extensively investigated.However,the knowledge of how RH regulates the lifecycles of human fungal pathogens is limited.In this study,we report that low atmospheric RH promotes the development of mating projections and same-sex(homothallic)mating in the human fungal pathogen Candida albicans.Low RH causes water loss in C.albicans cells,which results in osmotic stress and the generation of intracellular reactive oxygen species(ROS)and trehalose.The water transporting aquaporin Aqy1,and the G-protein coupled receptor Gpr1 function as cell surface sensors of changes in atmospheric humidity.Perturbation of the trehalose metabolic pathway by inactivating trehalose synthase or trehalase promotes same-sex mating in C.albicans by increasing osmotic or ROS stresses,respectively.Intracellular trehalose and ROS signal the Hog1-osmotic and Hsf1-Hsp90 signaling pathways to regulate the mating response.We,therefore,propose that the cell surface sensors Aqy1 and Gpr1,intracellular trehalose and ROS,and the Hog1-osmotic and Hsf1-Hsp90 signaling pathways function coordinately to regulate sexual mating in response to low atmospheric RH conditions in C.albicans.

A metabolite from commensal Candida albicans enhances the bactericidal activity of macrophages and protects against sepsis

The gut microbiome is recognized as a key modulator of sepsis development.However,the contribution of the gut mycobiome to sepsis development is still not fully understood.Here,we demonstrated that the level of Candida albicans was markedly decreased in patients with bacterial sepsis,and the supernatant of Candida albicans culture significantly decreased the bacterial load and improved sepsis symptoms in both cecum ligation and puncture(CLP)-challenged mice and Escherichia coli-challenged pigs.Integrative metabolomics and the genetic engineering of fungi revealed that Candida albicans-derived phenylpyruvate(PPA)enhanced the bactericidal activity of macrophages and reduced organ damage during sepsis.Mechanistically,PPA directly binds to sirtuin 2(SIRT2)and increases reactive oxygen species(ROS)production for eventual bacterial clearance.Importantly,PPA enhanced the bacterial clearance capacity of macrophages in sepsis patients and was inversely correlated with the severity of sepsis in patients.Our findings highlight the crucial contribution of commensal fungi to bacterial disease modulation and expand our understanding of the host-mycobiome interaction during sepsis development.

Relationship between antifungal resistance of fluconazole resistant Candida albicans and mutations in ERG11 gene

Background The cytochrome P450 lanosterol 14a-demethylase （Ergllp） encoded by ERG11 gene is the primary target for azole antifungals. Changes in azole affinity of this enzyme caused by amino acid substitutions have been reported as a mechanism of azole antifungal resistance. This study aimed to investigate the relationship between amino acid substitutions in Erg11 p from fluconazole resistant Candida a/bicans （C. albicans） isolates and their cross-resistance to azoles. Methods Mutations in ERG11 gene were screened in 10 clinical isolates of fluconazole resistant C. albicans strains. DNA sequence of ERG11 was determined by PCR based DNA sequencing. Results In the 10 isolates, 19 types of amino acid substitutions were found, of which 10 substitutions （F72S, F103L, F1451, F198L, G206D, G227D, N349S, F416S, F422L and T482A） have not been reported previously. Mutations in ERG11 gene were detected in 9 isolates of fluconazole resistant C. albicans, but were not detected in 1 isolate. Conclusions Although no definite correlation was found between the type of amino acid substitutions in Ergllp and the phenotype of cross-resistance to azoles, the substitutions F72S, F1451 and G227D in our study may be highly associated with resistance to azoles because of their special location in Erg11p.

Insoluble β-glucan from the cell wall of Candida albicans induces immune responses of human THP-1 monocytes through Dectin-1

Background β-glucan is the major structure component of Candida albicans （C. albicans） cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor （PRR） can recognize fungal β-glucan and induce immune responses. In this study, we sought to clarify whether insoluble β-glucan from the cell wall of C. albicans （CalG） could induce immune responses in human THP-1 monocytes （a human acute monocytic leukemia cell line） and to determine the underlying mechanisms. Methods Human THP-1 monocytes were challenged with CalG in vitro. The mRNA expression of Dectin-1, Toll-like receptors （TLR2）, proinflammatory cytokine （TNF-a） and chemokine （IL-8） was assayed by real-time reverse transcription polymerase chain reaction （RT-PCR）. The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay （ELISA）. H2O2 release was determined by microplate fluorescent assay. Western blotting was used to analyze IKB-a phosphorylation and degradation. Results Exposure of THP-1 monocytes to CalG led to increased gene expression and secretion of TNF-a and IL-8. CalG induced H2O2 release in a time-dependent manner. CalG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-a, IL-8 and H2O2 release. CalG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CalG resulted in the activation of NF-KB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CalG-induced production of TNF-a and H2O2 in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor （polymyxin B）. Conclusion CalG may play a role in activation of immune responses in human THP-1 cells throuah Dectin-1, not TLR2.

Lactobacillus crispatus Modulates Vaginal Epithelial Cell Innate Response to Candida albicans

Background： Vulvovaginal candidiasis is caused by Candida albicans. The vaginal epithelium, as the first site of the initial stage of infection by pathogens, plays an important role in resisting genital tract infections. Moreover, lactobacilli are predominant members of the vaginal microbiota that help to maintain a normal vaginal microenvironment. Therefore, Lactobacillus crispatus was explored for its capacity to intervene in the immune response of vaginal epithelial cells VK2/E6E7 to C. albicans. Methods： We examined the interleukin-2 （IL-2）, 4, 6, 8, and 17 produced by VK2/E6E7 cells infected with C. albicans and treated with L. crispatus in vitro. The capacity ofL. crispatus to adhere to VK2/E6E7 and inhibit C. albicans growth was also tested by scanning electron microscopy （SEM） and adhesion experiments. Results： Compared with group VK2/E6E7 with C. albicans, when treated with L. crispatus, the adhesion of C. albicans to VK2/E6E7 cells decreased significantly by 52.87 ± 1.22%, 47.03 ± 1.35%, and 42.20 ± 1.55% under competition, exclusion, and displacement conditions, respectively. SEM revealed that the invasion of C. albicans into VK2/E6E7 cells was caused by induced endocytosis and active penetration. L. crispatus could effectively protect the cells from the virulence ofhyphae and spores of C. albicans and enhance the local immune function of the VK2/E6E7 cells. The concentrations of IL-2, 6, and 17 were upregulated significantly （P 〈 0.0 1） and that of IL-8 were downregulated significantly （P 〈 0.0 1） in infected VK2/E6E7 cells treated with L. crispatus. The concentration of IL-4 was similar to that of the group VK2/ E6E7 with C. albicans （24.10 ± 0.97 vs. 23.12 ±0.76 pg/ml, P= 0.221）. Conclusions： L. crispatus can attenuate the virulence of C. albicans, modulate the secretion of cytokines and chemokines, and enhance the immune response of VK2/E6E7 cells in vitro. The vaginal mucosa has a potential function in the local immune responses against pathogens that can be promoted by L. crispatus.

Effects of Two Curcuminoids on Candida albicans

Objective To investigate and compare the action of curcuminoids on the causal pathogens of Candida albicans growth. Methods The effects of curcumin (CUR) and demethoxycurcumin (DMC) on C. albicans growth were first investigated and compared by microcalorimetry coupled with multiple analytical methods. The quantitative thermo-kinetic parameters obtained from these curves were analyzed to show difference of the actions. Results By analyzing the main parameters screened from principal component analysis together with 50% inhibiting concentration values, it was demonstrated that both CUR and DMC showed good antifungal activities and CUR was stronger. It was further concluded from structure-activity relationship that the existence of methoxy group might enhance lipophilicity of the mother nucleus, which made it easier for the molecular to enter into the cell membrane of fungi to inhibit its growth. Conclusion This study provides a new method for screening new antifungal agents with high efficacy and low toxicity. Meanwhile, it contributes to the application of curcuminoids as food additive, colorant, and drug. Microcalorimetry is real-time, online, and dynamic, and it could be used to characterize the subtle difference among the effects of synthetic and natural products on the vital process of fungi.

Increased Filamentous Growth of Candida albicans in Simulated Microgravity

Knowledge of simulated microgravity （SMG）-induced changes in the pathogenicity of microorganisms is important for success of long-term spaceflight. In a previous study using the high aspect ratio vessel bioreactor, we showed that the yeast species Saccharomyces cerevisiae underwent a significant phenotypic response when grown in modeled microgravity, which was reflected in the analysis of gene expression profiles. In this study, we establish that Candida albicans responds to SMG in a similar fashion, demonstrating that there is a conserved response among yeast to this environmental stress. We also report that the growth of C. albicans in SMG results in a morphogenic switch that is consistent with enhanced pathogenicity. Specifically, we observed an increase in filamentous forms of the organism and accompanying changes in the expression of two genes associated with the yeasthyphal transition. The morphological response may have significant implications for astronauts＇ safety, as the fungal pathogen may become more virulent during spaceflight.

Genome-wide expression profiling of the response to terbinafine in Candida albicans using a cDNA microarray analysis

Background Candida albicans is the most frequently seen opportunistic human fungal pathogen. Terbinafine is an allylamine antifungal agent that has been proven to have high clinical efficacy in the therapy of fungal infections, the mechanism of action of terbinafine involves the specific inhibition of fungal squalene epoxidase, resulting in ergosterol deficiency and accumulation of intracellular squalene. We used cDNA microarray analysis technology to monitor global expression profile changes of Candida albicans genes in response to terbinafine treatment, and we anticipated a panoramic view of the responses of Candida albicans cells to the representatives of allylamine antifungal agents at the molecular level in an effort to identify drug class-specific and mechanism-independent changes in gene expression.Methods Candida albicans strain ATCC 90028 was exposed to either medium alone or terbinafine at a concentration equivalent to the 1/2 minimal inhibitory concentrations （MICs, 4 mg/L） for 90 minutes. RNA was isolated and gene expression profiles were compared to identify the changes in the gene expression profile using a cDNA microarray analysis. Differential expression of 10 select genes detected by cDNA microarray analysis was confirmed by semi-quantitative reverse transcription-polymerase chain reaction （RT-PCR）. Results A total of 222 genes were found to be responsive to terbinafine, including 121 up-regulated genes and 101 down-regulated genes. These included genes encoding membrane transport proteins belonging to the members of the ATP-binding cassette （ABC） or major facilitator supeffamily （MFS; CDR1, AGP2, GAP6, PHO84, HOL3, FCY23, VCX1）, genes involved in stress response and detoxification （CDR1, AGP2, HOL3）, and gene involved in the ergosterol biosynthesis pathway （ERG12）. The results of semi-quantitative RT-PCR were consistent with that of the cDNA microarray analysis. Conclusions The up-regulation of the gene encoding the multidrug resistance efflux pump CDR1 may contribute to the terbinafine resistance in Candida albicans. However, the precise roles of other affected genes remain unclear, further studies of these genes and their respective products that play roles in the context of antifunqal resistance are warranted.