Formation In Candida Albicans Research Articles

Menthol as an effective inhibitor of quorum sensing and biofilm formation in Candida albicans and Candida glabrata by targeting the transcriptional repressor TUP1.

Menthol, a natural quorum sensing molecule, is derived from the Mentha species. Combating pathogenicity by inactivating quorum sensing is an emerging approach. Therefore, our objective was to investigate anti-quorum sensing and anti-biofilm potentials of menthol in Candida albicans and Candida glabrata. The antifungal properties of menthol were evaluated using a broth microdilution assay and a time-kill assay, and its effects on quorum sensing-mediated virulence factors, cellular reactive oxygen species (ROS), and biofilm formation were tested by evaluating TUP1 expression levels in both C. albicans and C. glabrata. Quorum sensing-mediated virulence factors and biofilm formation were inhibited by menthol in both C. albicans and C. glabrata. Furthermore, coinciding with elevated ROS levels, mRNAs of the quorum sensing-related gene TUP1 were upregulated in both C. albicans and C. glabrata. This study highlights the anti-quorum sensing potential of menthol through the inhibition of quorum sensing-mediated virulence factors, ROS generation, and biofilm development by targeting TUP1, which could have potential in the treatment of Candida infections.

ASLdC3: A Derivative of Acidic Sophorolipid Disrupts Mitochondrial Function, Induces ROS Generation, and Inhibits Biofilm Formation in Candida albicans.

Fungal infections account for more than 140 million cases of severe and life-threatening conditions each year, causing approximately 1.7 million deaths annually. Candida albicans and related species are the most common human fungal pathogens, causing both superficial (mucosal and cutaneous) and life-threatening invasive infections (candidemia) with a 40-75% mortality rate. Among many virulence factors of Candida albicans, morphological transition from yeast to hyphae, secretion of hydrolytic enzymes, and formation of biofilms are considered to be crucial for pathogenicity. However, the arsenals for the treatment against these pathogens are restricted to only a few classes of approved drugs, the efficacy of which is being compromised by host toxicity, fungistatic activity, and the emergence of drug resistance. In this study, we have described the development of a molecule, exhibiting excellent antifungal activity (MIC 8 μg/mL), by tailoring acidic sophorolipids with aryl alcohols via enzyme catalysis. This novel derivative, ASLdC3, is a surface-active compound that lowers the surface tension of the air-water interface up to 2-fold before reaching the critical micelle concentration of 25 μg/mL. ASLdC3 exhibits excellent antibiofilm properties against Candida albicans and other nonalbicans Candida species. The molecule primarily exhibits its antifungal activity by perturbing mitochondrial function through the alteration of the mitochondrial membrane potential (MMP) and generation of reactive oxygen species (ROS). The ROS damages fungal cell membrane function and cell wall integrity, eventually leading to cell death. ASLdC3 was found to be nontoxic in in vitro assay and nonhemolytic. Besides, it does not cause toxicity in the C. elegans model. Our study provides a valuable foundation for the potential of acidic sophorolipid as a nontoxic, biodegradable precursor for the design and synthesis of novel molecules for use as antimicrobial drugs as well as for other clinical applications.

Antimicrobial and anti-biofilm properties of oleuropein against Escherichia coli and fluconazole-resistant isolates of Candida albicans and Candida glabrata

BackgroundSide effects associated with antimicrobial drugs, as well as their high cost, have prompted a search for low-cost herbal medicinal substances with fewer side effects. These substances can be used as supplements to medicine or to strengthen their effects. The current study investigated the effect of oleuropein on the inhibition of fungal and bacterial biofilm in-vitro and at the molecular level.Materials and methodsIn this experimental study, antimicrobial properties were evaluated using microbroth dilution method. The effect of oleuropein on the formation and eradication of biofilm was assessed on 96-well flat bottom microtiter plates and their effects were observed through scanning electron microscopy (SEM). Its effect on key genes (Hwp1, Als3, Epa1, Epa6, LuxS, Pfs) involved in biofilm formation was investigated using the quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) method.ResultsThe minimum inhibitory concentration (MIC) and minimum fungicidal/bactericidal concentration (MFC/MBC) for oleuropein were found to be 65 mg/ml and 130 mg/ml, respectively. Oleuropein significantly inhibited biofilm formation at MIC/2 (32.5 mg/ml), MIC/4 (16.25 mg/ml), MIC/8 (8.125 mg/ml) and MIC/16 (4.062 mg/ml) (p < 0.0001). The anti-biofilm effect of oleuropein was confirmed by SEM. RT-qPCR indicated significant down regulation of expression genes involved in biofilm formation in Candida albicans (Hwp1, Als3) and Candida glabrata (Epa1, Epa6) as well as Escherichia coli (LuxS, Pfs) genes after culture with a MIC/2 of oleuropein (p < 0.0001).ConclusionsThe results indicate that oleuropein has antifungal and antibacterial properties that enable it to inhibit or destroy the formation of fungal and bacterial biofilm.

Green synthesis of biogenic selenium nanoparticles functionalized with ginger dietary extract targeting virulence factor and biofilm formation in Candida albicans

To treat the systemic infections caused by Candida albicans (C. albicans), various drugs have been used, however, infections still persisted due to virulence factors and increasing antifungal resistance. As a solution to this problem, we synthesized selenium nanoparticles (SeNPs) by using Bacillus cereus bacteria. This is the first study to report a higher (70 %) reduction of selenite ions into SeNPs in under 6 h. The as-synthesized, biogenic SeNPs were used to deliver bioactive constituents of aqueous extract of ginger for inhibiting the growth and biofilm (virulence factors) in C. albicans. UV–visible spectroscopy revealed a characteristic absorption at 280 nm, and Raman spectroscopy showed a characteristic peak shift at 253 cm−1 for the biogenic SeNPs. The synthesized SeNPs are spherical with 240–250 nm in size as determined by electron microscopy. Fourier transform infrared spectroscopy confirmed the functionalization of antifungal constituents of ginger over the SeNPs (formation of Ginger@SeNPs nanoconjugates). In contrast to biogenic SeNPs, nanoconjugates were active against C. albicans for inhibiting growth and biofilm formation. In order to reveal antifungal mechanism of nanoconjugates', real-time polymerase chain reaction (RT-PCR) analysis was performed, according to RT-PCR analysis, the nanoconjugates target virulence genes involved in C. albicans hyphae and biofilm formation. Nanoconjugates inhibited 25 % growth of human embryonic kidney (HEK) 293 cell line, indicating moderate cytotoxicity of active nanoconjugates in an in-vitro cytotoxicity study. Therefore, biogenic SeNPs conjugated with ginger dietary extract may be a potential antifungal agent and drug carrier for inhibiting C. albicans growth and biofilm formation.

The Early Endocytosis Gene PAL1 Contributes to Stress Tolerance and Hyphal Formation in Candida albicans.

The endocytic and secretory pathways of the fungal pathogen Candida albicans are fundamental to various key cellular processes such as cell growth, cell wall integrity, protein secretion, hyphal formation, and pathogenesis. Our previous studies focused on several candidate genes involved in early endocytosis, including ENT2 and END3, that play crucial roles in such processes. However, much remains to be discovered about other endocytosis-related genes and their contributions toward Candida albicans secretion and virulence. In this study, we examined the functions of the early endocytosis gene PAL1 using a reverse genetics approach based on CRISPR-Cas9-mediated gene deletion. Saccharomyces cerevisiae Pal1 is a protein in the early coat complex involved in clathrin-mediated endocytosis that is later internalized with the coat. The C. albicans pal1Δ/Δ null mutant demonstrated increased resistance to the antifungal agent caspofungin and the cell wall stressor Congo Red. In contrast, the null mutant was more sensitive to the antifungal drug fluconazole and low concentrations of SDS than the wild type (WT) and the re-integrant (KI). While pal1Δ/Δ can form hyphae and a biofilm, under some hyphal-inducing conditions, it was less able to demonstrate filamentous growth when compared to the WT and KI. The pal1Δ/Δ null mutant had no defect in clathrin-mediated endocytosis, and there were no changes in virulence-related processes compared to controls. Our results suggest that PAL1 has a role in susceptibility to antifungal agents, cell wall integrity, and membrane stability related to early endocytosis.

Potential anti-adhesion activity of novel carbosilane zwitterionic dendrimers against eukaryotic and prokaryotic pathogenic microorganisms

The development of biofilms on different surfaces continues to be a major public health problem. The antimicrobial resistance and the difficulty of finding drugs capable of combating these established biofilms generates the urgent need to find compounds that prevent cells from settling and establishing of these complex communities of microorganisms. Zwitterionic modification of nanomaterials allows the formation of a hydration layer, and this highly hydrophilic surface provides antifouling properties as well as a good biocompatibility by preventing non-specific interactions. Thus, they are appropriate candidates to prevent microbial adhesion to different surfaces and, in consequence, avoid biofilm formation. For this reason, we have incorporated zwitterionic moieties in multivalent systems, as are carbosilane dendrimers. Characterization of these systems was performed using nuclear magnetic resonance and mass spectrometry. It has been analysed if the new molecules have capacity to inhibit the biofilm formation in Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The results showed that they were more effective against S. aureus, observing a biofilm reduction of 81.5% treating with 32 mg/L of G2SiZWsf dendrimer and by 72.5% using 32 mg/L of the G3SiZWsf dendrimer. Finally, the absence of cytotoxicity was verified by haemolysis and cytotoxicity studies in human cells lines.

Inhibitory Effects of the Fungal Pigment Rubiginosin C on Hyphal and Biofilm Formation in Candida albicans and Candida auris.

The two fungal human pathogens, Candida auris and Candida albicans, possess a variety of virulence mechanisms. Among them are the formation of biofilms to protect yeast against harsh conditions through the development of (pseudo)hyphae whilst also facilitating the invasion of host tissues. In recent years, increased rates of antifungal resistance have been associated with C. albicans and C. auris, posing a significant challenge for the effective treatment of fungal infections. In the course of our ongoing search for novel anti-infectives, six selected azaphilones were tested for their cytotoxicity and antimicrobial effects as well as for their inhibitory activity against biofilm and hyphal formation. This study revealed that rubiginosin C, derived from stromata of the ascomycete Hypoxylon rubiginosum, effectively inhibited the formation of biofilms, pseudohyphae, and hyphae in both C. auris and C. albicans without lethal effects. Crystal violet staining assays were utilized to assess the inhibition of biofilm formation, while complementary microscopic techniques, such as confocal laser scanning microscopy, scanning electron microscopy, and optical microscopy, were used to investigate the underlying mechanisms. Rubiginosin C is one of the few substances known to effectively target both biofilm formation and the yeast-to-hyphae transition of C. albicans and C. auris within a concentration range not affecting host cells, making it a promising candidate for therapeutic intervention in the future.

Effect of Peganum harmala Extract on Biofilm and Involved Gene Expression in Biofilm Production of Candida albicans

Background: Since common drug therapies cannot eradicate Candida biofilm, extensive studies are required to develop more effective antifungal compounds and identify their mechanism of action against Candida biofilm. Peganum harmala L. is a traditional medicinal plant, the seeds of which have been used to treat various diseases. Objectives: This study aimed to investigate the anti-biofilm mechanisms of P. harmala extract (PHE) and the expression of CAT1, EFG1, and BCR1 genes involved in oxidative stress response and biofilm formation in Candida albicans. Methods: Anti-biofilm activity of PHE was evaluated by crystal violet assay to determine biofilm formation on 33 C. albicans isolates. Finally, a real-time polymerase chain reaction was performed to analyze the effect of PHE on the expression of CAT1, EFG1, and BCR1 genes in C. albicans. Results: This study determined the minimum biofilm eradication concentration (MBEC) of 15 isolates in concentrations between 0.49 - 3.9 μg/mL of P. harmala extract. Statistical analysis showed that the exposure of C. albicans biofilm to PHE significantly reduced the expression of CAT1 mRNA in C. albicans isolates (P = 0.0068). However, no significant difference was observed in the expression of EFG1 and BCR1 genes. Conclusions: The results demonstrated that PHE significantly decreased CAT1 expression in C. albicans cells treated with the herbal extract. PHE is likely to accumulate hydrogen peroxide (H2O2) by reducing CAT1 expression and disrupting the pro-oxidant/antioxidant balance that leads to the overproduction of reactive oxygen species (ROS) and can cause damage to cellular components and eventually destroy C. albicans biofilm.

Erg6 Acts as a Downstream Effector of the Transcription Factor Flo8 To Regulate Biofilm Formation in Candida albicans.

The yeast-to-hyphal morphotype transition and subsequent biofilm formation are important virulence factors of Candida albicans and are closely associated with ergosterol biosynthesis. Flo8 is an important transcription factor that determines filamentous growth and biofilm formation in C. albicans. However, the relationship between Flo8 and regulation of the ergosterol biosynthesis pathway remains elusive. Here, we analyzed the sterol composition of a flo8-deficient C. albicans strain by gas chromatography-mass spectrometry and observed the accumulation of the sterol intermediate zymosterol, the substrate of Erg6 (C-24 sterol methyltransferase). Accordingly, the transcription level of ERG6 was reduced in the flo8-deficient strain. Yeast one-hybrid experiments revealed that Flo8 physically interacted with the ERG6 promoter. Ectopic overexpression of ERG6 in the flo8-deficient strain partially restored biofilm formation and in vivo virulence in a Galleria mellonella infection model. These findings suggest that Erg6 is a downstream effector of the transcription factor Flo8 that mediates the cross talk between sterol synthesis and virulence factors in C. albicans. IMPORTANCE Biofilm formation by C. albicans hinders its eradication by immune cells and antifungal drugs. Flo8 is an important morphogenetic transcription factor that regulates the biofilm formation and in vivo virulence of C. albicans. However, little is known about how Flo8 regulates biofilm formation and fungal pathogenicity. Here, we determined that Flo8 directly binds to the promoter of ERG6 to positively regulate its transcriptional expression. Consistently, loss of flo8 results in the accumulation of the substrate of Erg6. Moreover, ectopic overexpression of ERG6 at least partially restores the biofilm formation and virulence of the flo8-deficient strain both in vitro and in vivo. This work provides a new perspective on the metabolic link between transcription factors and morphotypes in C. albicans.

Cell progression of biofilm formation in Candida albicans and estimation of aspartic proteinase activity

Cell progression of biofilm formation in Candida albicans and estimation of aspartic proteinase activity

Antifungal activity of vitamin D3 against Candida albicans in vitro and in vivo

The incidence of intra-abdominal candidiasis (IAC), characterized by high morbidity and mortality, has become a serious concern. The limitations of current antifungal drugs on the market underscores the importance of the development of novel antifungal agents. In the present study, the antifungal activity of vitamin D3 (VD3) against various Candida species was investigated. In vitro, the broth microdilution method and solid plate assay confirmed that VD3 inhibited the growth of Candida spp. in a broad-spectrum, dose-dependent manner. VD3 also had a significant antifungal effect on the initiation, development, and maturation phases of biofilm formation in Candida albicans. The mechanism of VD3 action was explored by transcriptomics and reverse transcription quantitative PCR (RT-qPCR) analysis, and showed that VD3 affects ribosome biogenesis, coenzyme metabolism, and carbon metabolism. These results suggested that VD3 may have multitarget effects against C. albicans. In the murine IAC model, VD3 reduced the fungal burden in the liver, kidneys, and small intestine. Further histopathological analysis and quantification of plasma cytokine levels confirmed that VD3 treatment significantly decreased the infiltration of inflammatory cells and the levels of plasma interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Taken together, these findings suggest a new antifungal mechanism for VD3 and indicate that VD3 could be an effective therapeutic agent for use in IAC treatment.

S3.4e Unraveling the role of DOG genes in a novel alternative pathway of glycerol biosynthesis in Candida albicans and its influence on virulence

S3.4 Free oral paper session, September 21, 2022, 4:45 PM - 6:15 PMDOG genes, encoding for 2-deoxyglucose-6-phosphate phosphatase are low molecular weight phosphatases, with an unknown biological function. In contrast to Saccharomyces cerevisiae which has two DOG homologs, C. albicans only has one DOG gene. We hypothesized that DOG1 plays an important role under osmotic or ionic stress by biosynthesizing glycerol, which is known to be vital for biofilm formation and virulence of this pathogenic yeast, via a novel alternative pathway. The known classical pathway of glycerol production begins when the glycolytic intermediate molecule dihydroxyacetone phosphate (DHAP) is converted into glycerol-3-phosphate (G-3-P) by a pair of glycerol-3-phosphate-dehydrogenases, Gpd1 and Gpd2. G-3-P is further dephosphorylated into glycerol by glycerol-3-phosphate-phosphatases, Gpp1 and Gpp2. However, an alternative pathway, where DHAP is dephosphorylated into DHA, which is subsequently converted into glycerol has been proposed, but the enzymes involved in this process have not yet been described. We recently showed that in Saccharomyces cerevisiae, the DOG enzymes are involved in the production of DHA from DHAP, thereby allowing the synthesis of glycerol in the absence of the classical pathway. Overexpression of the DOG genes restored the osmo-tolerance of the gpp1Δ gpp2Δand gpd1Δ gpd2Δ double deletion strains. Furthermore, purified DOG enzymes could also convert DHAP into DHA (Awasthy et al., submitted). Since DOG1 has a potential role in biosynthesizing glycerol via an unconventional route, we are interested to determine its contribution in influencing virulence and biofilm formation in Candida albicans. This putative pathway has been overlooked for the past two decades, leaving behind an evident knowledge gap. We have now generated multiple deletion strains, using CRISPR Cas9, for the C. albicans counterparts of the GPP, GPD, and DOG genes as well as multiple DOG1 overexpression strains in which we observed the restoration of osmotic stress tolerance phenotypically and via growth curves. We also have NMR data showing the accumulation of various metabolites of central metabolism in these strains. Additionally, we have determined the possible role of DOG1 on virulence factors like morphogenesis, adhesion, and biofilm formation in vitro as well as in vivo, the latter with our catheter-based biofilm subcutaneous mouse model system. We also linked DOG1 and its role in glycerol biosynthesis to the survival of C. albicans inside macrophages. Finally, we would be setting up a high throughput small compound screening for this phosphatase as a potential antifungal drug target.

Melianone inhibits Secreted Aspartic Proteases (SAP), a Virulence Factor During Hyphal Formation in Candida albicans.

Candida albicans (C.-P. Robin) Berkhout, the pathogenic yeasts' ability to transform from yeast to hyphal forms in the bloodstream is essential during systemic infections. Among the several virulence factors studied, secreted aspartic proteinases (SAPs) involved in hyphal penetration are targets of putative hyphal inhibitors. Upregulation of SAP6 gene, (two-to 31- fold high) during budded to hyphal transition and lack of studies on its inhibition, prompted us to investigate this particular protein using in silico tools. Hyphal inhibition of germinating yeast cells by melianone, a triterpenoid, from Swietenia mahagoni (L.) Jacq. (Meliaceae) was observed at 0.1 μM (IC50). One of the targets of putative hyphal inhibitors, SAP, was assayed and for the first time, 50 % of the biological SAP activity was found to be inhibited by melianone at 0.125 μM. This data on SAP inhibition led us to analyse the 3-dimensional structure for SAP6 protein that was constructed through a combination of homology modelling and ab-initio method (Phyre2) and validated before performing Induced Fit Docking (IFD). Melianone formed H-bond and hydrophobic interactions with the crucial residues (ASP108, TYR160, ALA161, ASP162, ASP294, THR297, ASP379) in the catalytic site of SAP6 with a glide energy (-)54.9327 kcal/mol upon Induced Fit Docking (IFD). We report here for the first time on the SAP inhibitory ability of melianone at 0.125 uM. Being a small molecular mass inhibitor, binding with high affinity to the S3 pocket sites of SAP proteins provides evidence for pre-clinical testing of such compounds against fungal pathogens. The study is a valuable insight for further research on novel and effective inhibitors targeting SAP.

Ino80 is required for H2A.Z eviction from hypha-specific promoters and hyphal development of Candida albicans.

ATP‐dependent chromatin remodeling complexes play important roles in many essential cellular processes, including transcription regulation, DNA replication, and repair. Evicting H2A.Z, a variant of histone H2A, from the promoter of hypha‐specific genes is required for hyphal formation in Candida albicans. However, the mechanism that regulates H2A.Z removal during hyphal formation remains unknown. In this study, we demonstrated that Ino80, the core catalytic subunit of the INO80 complex, was recruited to hypha‐specific promoters during hyphal induction in Arp8 dependent manner and facilitated the removal of H2A.Z. Deleting INO80 or mutating the ATPase site of Ino80 impairs the expression of hypha‐specific genes (HSGs) and hyphal development. In addition, we showed that Ino80 was essential for the virulence of C. albicans during systemic infections in mice. Interestingly, Arp5, an INO80 complex‐specific component, acts in concert with Ino80 during DNA damage responses but is dispensable for hyphal induction. Our findings clarified that Ino80 was critical for hyphal development, DNA damage response, and pathogenesis in C. albicans.

Candida albicans biofilm formation and growth optimization for functional studies using response surface methodology.

Optimization of Candida albicans growth and biofilm formation is essential for understanding the recalcitrance of this pathogen to advance functional analysis on hospital tools and material surfaces. Optimization and quantification of biofilm have always been a challenge using the conventional one variable at a time (OVAT) method. The present study uses central composite design-based response surface methodology for optimization of conditions to induce growth and biofilm formation in Candida albicans on polystyrene microtiter plates. Statistical software package, Stat Soft®, STASTICA version 12.6 was used for data analysis. The variables considered in the design matrix were media pH, temperature, incubation period, shaker speed and inoculum size. A four-pronged quantification approach with XTT assay (cell viability), crystal violet assay (biofilm), calcofluor white assay and wet/dry weight measurements (cell mass) was used to understand different aspects of biofilm formation. Cell viability and cell mass were inversely related; however, biofilm was independent of these two factors. The study also highlighted the fact that foetal bovine serum does not significantly contribute to cell adhesion and in turn in vitro biofilm formation in some of the cultures. A high-throughput optimization of C. albicans growth and biofilm formation on polystyrene microplate has been developed and validated. This is a first time approach to optimize the interaction of parameters for C. albicans biofilm formation using RSM. Heterogeneity in growth conditions for local strains of C. albicans clinical isolates was observed. This microtiter plate-based method can be used for future screening of therapeutics for the control of C. albicans.

The novel antifungal agent AB-22 displays in vitro activity against hyphal growth and biofilm formation in Candida albicans and potency for treating systemic candidiasis.

Systemic candidiasis, which is mainly caused by Candida albicans, is a serious acute fungal infection in the clinical setting. In a previous study, we reported that compound 22h (designated as AB-22 in this study), a vinyl sulfate compound, is a fast-acting fungicidal agent against a broad spectrum of fungal pathogens. In this study, we aimed to further analyze the in vitro and in vivo efficacy of AB-22 against filamentation, biofilm formation, and virulence of C. albicans. Under in vitro hyphal growth-inducing condition, AB-22 effectively inhibited germ tube formation and hyphal growth, which are required for the initiation of biofilm formation. Indeed, AB-22 significantly suppressed C. albicans biofilm formation in a dose-dependent manner. Moreover, AB-22 treatment inhibited the normal induction of ALS3, HWP1, and ECE1, which are all required for hyphal transition in C. albicans. Furthermore, AB-22 treatment increased the survival of mice systemically infected with C. albicans. In conclusion, in addition to its fungicidal activity, AB-22 inhibits filamentation and biofilm formation in C. albicans, which could collectively contribute to its potent in vivo efficacy against systemic candidiasis.

Short peptides derived from EntV inhibit virulence and biofilm formation in Candida albicans

Candida albicans exists as a member of the commensal flora of the skin and gut where many complex polymicrobial interactions occur with genera such as Pseudomonas, Staphylococcus, and Streptococcus. Some of these interactions potentiate or inhibit virulence. The bacterial gastrointestinal commensal speciesEnterococcus faecalisproduces a small peptide, EntV, that modulates C. albicans virulence. The active 68 amino acid EntV peptide inhibits biofilm formationin vitro; biofilm-related infections are difficult to treat with current therapeutics. EntV also attenuates fungal virulence in a Caenorhabditis elegansinfection model and a murine oral candidiasis model. We sought to identify the regions of EntV responsible for the anti-fungal activity, and based on structural information, we hypothesized that it could be localized to a single helix of the mature peptide. In this study, we report that smaller peptides derived from this helix ranging from 12 to 16 amino acids have equal to improved efficacy in inhibiting C. albicans virulence andbiofilm formation. These smaller peptides attenuate virulence in the C. elegans infection model, inhibit initial adhesion to abiotic surfaces, and reduce the size of mature biofilms measured by confocal microscopy. Further trimming of these peptides to fewer than 11 amino acids reduces and eventually eliminates activity. These data indicate that EntV-derived peptides warrant further investigation as potential non-fungicidal additives to medical devices and antifungal therapeutics.

Detection of als1 and hwp1 genes involved in biofilm formation in Candida albicans isolated from catheter associated candiduria.

Background: Candida species are opportunistic fungal pathogens that can affect immune compromised patients and may cause life threatening infections. Biofilm formation is an important virulence factor that enables Candida species to invade the host tissues. This study aimed to assess the ability of Candida albicans to form biofilm in patients with catheter associated candiduria and to determine the presence of some genes involved in biofilm formation at the molecular level. Methods: This cross-sectional descriptive study was carried out from June 2019 to June 2020 on 93 catheterized patients admitted to different wards at SCUHs, Ismailia. Candida albicans strains were identified phenotypically by their growth on sabouraud dextrose agar, Gram staining, growth on hypertonic sabouraud broth, chlamydospore formation and germ tube formation test. Biofilm formation was detected by tissue culture plate method. Detection of the genes involved in biofilm formation was done by PCR. Results: Twenty eight Candida albicans strains wereisolated from 36 Candida species. 9 isolates (32.1%) were strong biofilm producers, 6 isolates (21.4%) were moderate biofilm producers and 13 isolates (46.4%) were weak or non-biofilm producers. ALS1 gene was detected in 13 isolates (46.4%), while HWP1 gene was detected in 16 isolates (57.1 %). Conclusion: This study documented the prevalence of candiduria in catheterized patients and found a statistically significant higher prevalence of the tested biofilm forming genes among biofilm forming isolates as compared to the weak or non-biofilm forming ones; but additional studies should be carried out as the management of catheter associated caniduria is still controversial.

Non-antifungal drugs inhibit growth, morphogenesis and biofilm formation in Candida albicans.

The increased resistance/tolerance of Candida infections to antimicrobial treatment can be attributed to biofilm-associated cells. A way to overcome this situation is to re-purpose non-anti-fungal drugs that could be active against fungi. We have explored the potential of a small library of eighteen non-antifungal drugs used in different human diseases. Candida albicans was cultured in the presence and absence of different concentrations of these drugs. Subsequently, inhibition of growth, germ tube formation, adhesion, and biofilm development were studied. Out of eighteen drug molecules, six showed a reduction in planktonic and biofilm growth in a dose-dependent manner and three drugs inhibited germ tube formation. This study shows the potential of non-antifungal drugs for the development of new anti-Candida agents.

Sho1p Connects Glycolysis to Ras1-cAMP Signaling and Is Required for Microcolony Formation in Candida albicans.

Candida albicans is an opportunistic, dimorphic fungus that causes candidiasis in immunocompromised people. C. albicans forms specialized structures called microcolonies that are important for surface adhesion and virulence. Microcolonies form in response to specific environmental conditions and require glycolytic substrates for optimal growth. However, fungal signaling pathways involved in sensing and transmitting these environmental cues to induce microcolony formation have not been identified. Here, we show that the C. albicans Ras1-cAMP cascade is required for microcolony formation, while the Cek1-MAP kinase pathway is not required, and Hog1 represses microcolony formation. The membrane protein Sho1, known to regulate the Cek1 pathway in yeasts, was indispensable for C. albicans microcolony formation but regulated the Ras1-cAMP pathway instead, based upon diminished intracellular levels of cAMP and reduced expression of core microcolony genes, including HWP1, PGA10, and ECE1, in C. albicanssho1Δ cells. Based upon predicted physical interactions between Sho1 and the glycolytic enzymes Pfk1, Fba1, Pgk1, and Cdc19, we hypothesized that Sho1 regulates Ras1-cAMP by establishing cellular energy levels produced by glycolysis. Indeed, microcolony formation was restored in C. albicanssho1Δ cells by addition of exogenous intermediates of glycolysis, including downstream products of each predicted interacting enzyme (fructose 1,6 bisphosphate, glyceraldehyde phosphate, 3-phosphoglyceric acid, and pyruvate). Thus, C. albicans Sho1 is an upstream regulator of the Ras1-cAMP signaling pathway that connects glycolytic metabolism to the formation of pathogenic microcolonies.IMPORTANCEC. albicans microcolonies form extensive hyphal structures that enhance surface adherence and penetrate underlying tissues to promote fungal infections. This study examined the environmental conditions that promote microcolony formation and how these signals are relayed, in order to disrupt signaling and reduce pathogenesis. We found that a membrane-localized protein, Sho1, is an upstream regulator of glycolysis and required for Ras1-cAMP signaling. Sho1 controlled the Ras1-dependent expression of core microcolony genes involved in adhesion and virulence. This new regulatory function for Sho1 linking glycolysis to microcolony formation reveals a novel role for this fungal membrane protein.