The regulation of hyphae growth in Candida albicans

Switching off the yeast-to-hyphae transition in Yarrowia lipolytica through histone deacetylase inhibitors

Fungi can develop a variety of morphotypes to survive, colonize, adapt and prevail under different environmental conditions. In general, two morphological shapes encompass the others: yeast (unicellular) and hyphae (multicellular). Under specific conditions, some fungi can adopt these two cellular morphologies, and for this reason, they are called dimorphic. Histone acetylation and deacetylation are well-known important mechanisms of chromatin remodelling that control cell differentiation processes as dimorphism. The reactions involved are catalysed by histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. In the present work, we used Yarrowia lipolytica as a dimorphic fungal model to investigate the effect of HDAC chemical inhibition on the growth and yeast-to-hyphae switch of fungi. For this purpose, we tested the compounds sodium butyrate (SB) and valproic acid (VPA) as epigenetic modulators. Our results indicated that Y. lipolytica tolerates high doses of these inhibitors due to its lipolytic nature. However, once the metabolic capability of the fungus is overcome, SB and VPA strongly suppress hyphal growth, suggesting that histone acetylation plays a pivotal role in the regulation of this process.

Candidalysin biology and activation of host cells

Candida albicans is an opportunistic fungal pathogen that can cause life-threatening systemic infections and distressing mucosal infections. A major breakthrough in understanding C. albicans pathogenicity was the discovery of candidalysin, the first cytolytic peptide toxin identified in a human pathogenic fungus. Secreted by C. albicans hyphae and encoded by the ECE1 gene, this 31-amino acid peptide integrates into and permeabilizes host cell membranes, causing damage across diverse cell types. Beyond its cytolytic activity, candidalysin can trigger potent innate immune responses in epithelial cells, macrophages, and neutrophils. Additionally, candidalysin plays a key role in nutrient acquisition during infection. This review explores the biology of candidalysin, its role in host cell activation, and extends the discussion to non-candidalysin Ece1p peptides, shedding light on their emerging significance.

Candida albicans colonization on CAD-CAM denture resin surface

OBJECTIVE

This study assessed the biofilm formation of C. albicans on milled and 3D-printed denture resin surfaces and compared it to a control group of conventional heat-polymerized polymethylmethacrylate (PMMA) resin group.

METHODS

Three groups of denture resin samples (n = 27) were fabricated: milled (Ivotion, Ivoclar Vivadent), 3D-printed (Saremco Print Denturetec), and heat-polymerized PMMA controls. Samples (8 mm × 3 mm) were CAD-designed, manufactured, quality-checked, and sterilized. C. albicans (GEGE1122.01) biofilms were grown on resin discs, incubated at 37 °C for 16 h, detached, and quantified. SEM analysis assessed biofilm morphology. Statistical analysis was conducted using non-parametric tests (p < 0.05).

RESULTS

The lowest median biofilm attachment (1.2 × 10⁶ CFU/biofilm, IQR: 3.4 × 10⁵ - 5.6 × 10⁶) with high variability was observed in the control group. The milled group displayed significantly higher biofilm formation (6.4 × 10⁶ CFU/biofilm, IQR: 5.9 × 10⁶ - 7.6 × 10⁶, p = 0.0051) with least variation. The biofilm attachment on 3D-printed discs (4.8 × 10⁶ CFU/biofilm, IQR: 3.6 × 10⁶ - 6.2 × 10⁶) was intermediate between the control and milled groups. SEM findings revealed sparse microcolonies with dense, multi-layered biofilms of yeast and pseudohyphal forms in the control and milled groups. 3D-printed group had moderately dense biofilms, where yeast and pseudohyphae were dominant, but true hyphae were also consistently observed.

CONCLUSION

This study reveals significant differences in the C. albicans biofilm formation across the resin types, with 3D-printed surfaces showing increased hyphal growth and potential for higher virulence.

CLINICAL SIGNIFICANCE

Understanding the impact of fabrication methods on microbial colonization is essential for improving denture hygiene and patient outcomes. Dentists and prosthodontists should consider these findings when selecting materials for patients at high risk of fungal infections, such as immunocompromised individuals or elderly denture wearers.

Effects of Nisin A Combined with Antifungal Drug Against Growth of Candida Species

Background/Objectives: Nisin A, an antimicrobial peptide produced by Lactococcus lactis, primarily shows antimicrobial activity against Gram-positive bacteria, with efficacy increased when used in combination with an antimicrobial drug. On the other hand, oral candidiasis, caused by Candida, occurs in immunocompromised patients and requires antifungal therapy. However, antifungal drug-resistant Candida strains are increasing worldwide, leading to serious problems. Methods: To examine the effects of nisin A against Candida species, we investigated the combined effects of nisin A and antifungal drugs on the growth and viability of Candida strains. Results: While nisin A alone had no antifungal effect, together with amphotericin (AMPH), it showed synergistic effects towards C. albicans, as well as the non-albican strains C. glabrata, C tropicalis, and C. parapsilosis in checkerboard assay results. Furthermore, nisin A with miconazole (MCZ) or micafungin (MCFG) demonstrated a synergistic or additive effect on those strains. Cell viability assay results showed that nisin A enhanced the fungicidal activity of AMPH against both C. albicans and C. glabrata. Biofilm reduction assays showed that nisin A with AMPH, MCZ, or MCFG inhibited biofilm activity against C. albicans as compared with each antifungal drug alone. Finally, nisin A with AMPH, MCZ, or MCFG resulted in a reduced minimum inhibitory concentration of those antifungal drugs against clinically isolated C. albicans and C. glabrata.Conclusions: When used in combination with nisin A, the antifungal drug dosage can be lowered, thus helping to prevent adverse side effects and the emergence of drug-resistant oral Candida species.

Isolation and characterization of a phage against the multidrug-resistant Candida albicans ATCC 10231 strain from raw sewage

The financial cost of resistance to antibiotics is constantly increasing. Viruses are possible substitutes and effective treatments for diseases caused by multidrug-resistant pathogens. The aim of the present study is to isolate a Candida albicans virus from raw sewage and characterize it. Herein, direct and enrichment approaches were used for virus isolation from a raw sewage sample collected from the El-Rahmania wastewater treatment plant, El-Behiera Governorate, Egypt. Using a transmission electron microscope, the viral particle was found to have a hexagonal head with a diameter of approximately 160 nm and a short tail with a length of 87 nm. The virus was treated at different temperature ranges (30-90 °C) for 5, 15, 30, and 60 min. The virus titer was stable at 30 °C, 40 °C, and 50 °C for 5-60 min and partially stable at 60 °C, 70 °C, and 80 °C. The virus kept its activity at a wide range between pH 5-10, while it was completely inactivated in highly acidic (pH < 5) and alkaline (pH > 10) conditions. The effect of osmotic shock on the isolated virus showed 64 % survivability. The effects of five organic solvents on viral particles-chloroform, ethanol, methanol, dimethyl sulfoxide (DMSO), and ethyl acetate-showed 0.7, 1.1, 1.2, 1.4, and 1.7 log10 reductions in initial viral titer, respectively. This study provided new information about the characterization of the virus isolated against Candida albicans, which will be useful for future formulation of a successful therapeutic viral agent against Candida albicans.

Identification of the ADH gene family in Trichosporon asahii and the role of TaADH_like in pathogenicity and fluconazole resistance

Alcohol dehydrogenase has been studied in regulation of fungal growth and development, stress response and pathogenesis, but its function in T. asahii remains unexplored. In this study, we analyzed the ADH gene family in T. asahii for the first time, identifying six ADH genes and containing conserved ADH_N and ADH_Zinc_N domains. We constructed an overexpression strain of the most significantly differentially expressed gene TaADH_like and compared its phenotypes with those of the wild-type strain, focusing on colony morphology, biofilm biomass, stress response, drug resistance, and pathogenicity. The results showed that TaADH_like overexpression reduced sensitivity to hypoxic conditions, altered the hyphae-to-yeast transition, and led to slower growth, decreased colonization ability, reduced tissue damage, and lower lethality. Increased osmotic stress sensitivity and the involvement of the HOG MAPK pathway in the hyphae-to-yeast conversion contributed to the reduced colonization capacity of T. asahii. Furthermore, the overexpression of TaADH_like promoted biofilm formation and led to a slight enhancement in fluconazole resistance in T. asahii. This study is the first to elucidate the function of the alcohol dehydrogenase gene in T. asahii, providing a foundation for future genetic research on this pathogen.

Hyphal penetration is the major pathway of translocation of Candida albicans across the blood-cerebrospinal fluid barrier

BACKGROUND

Despite the availability of potent antifungal compounds, invasive fungal disease poses significant morbidity and mortality in immunocompromised patients. Candida albicans is one of the leading pathogens in this setting, and may affect the central nervous system (CNS), which is an extremely severe form of the infection. As the exact pathogenesis of Candida CNS infection is not clear, we investigated the mechanisms and effects of C. albicans transmigration into the CNS, which will be helpful for diagnosis, prevention and treatment.

METHODS

We used a human in vitro model of the Blood-Cerebrospinal Fluid Barrier (BCSFB), and we investigated the mechanisms of Candida albicans translocation into the CNS. Translocation was evaluated using immunofluorescence analysis focusing on tight and adherens junctions and the actin cytoskeleton. Barrier integrity was monitored via measurement of transepithelial resistance and the paracellular permeability of dextran. LIVE/DEAD assays were applied for viability controls and a cytometric bead array was performed to detect cytokine secretion of plexus epithelial cells.

RESULTS

Translocation at low doses occurs transcellularly in the absence of cytotoxicity or secretion of proinflammatory cytokines. This is accomplished by the formation of a tunnel-like structure exploiting the actin cytoskeleton. With higher infection doses of Candida albicans, a reduction in barrier integrity due to disruption of tight and adherens junctions was observed and cytotoxicity also increased.

CONCLUSION

Our findings reveal that Candida albicans can use transcellular translocation to invade into the CNS and is able to circumvent major host immune response, which may impact on diagnostic and preventive strategies.

Analyses of hyphal diversity in Trichosporonales yeasts based on fluorescent microscopic observations

In dimorphic yeasts, hyphal growth is primarily associated with infection and mycosis progression, with Trichosporon asahii causing deep-seated mycosis and summer-type hypersensitivity pneumonitis. Magnesium accelerates hyphal growth in T. asahii, leading to multi-septation, vacuolar expansion, and decreased lipid droplet size. However, the commonality of these phenotypes has not been studied in Trichosporonales yeasts. Therefore, to explore whether similar magnesium-induced phenotypes occur across Trichosporonales yeasts, we examined hyphal growth, multi-septation, vacuolar extension, and lipid droplet size and number in 30 species. Cell length increased with magnesium treatment in 13 yeasts: 5 Trichosporon (T. asahii, Trichosporon aquatile, Trichosporon asteroides, Trichosporon coremiiforme, and Trichosporon ovoides), three Apiotrichum (Apiotrichum brassicae, Apiotrichum montevideense, and Apiotrichum veenhuisii), three Cutaneotrichosporon (Cutaneotrichosporon cavernicola, Cutaneotrichosporon cutaneum, and Cutaneotrichosporon dermatis), Pascua guehoae, and Takashimella koratensis. C. dermatis also underwent pseudo-hyphal growth. Multi-septation increased in seven dimorphic yeasts, including five Trichosporon spp., Trichosporon faecale, and C. dermatis. The vacuolar area was significantly extended in T. asahii, T. aquatile, T. ovoides, and C. dermatis. Lipid droplet size increased only in Trichosporon inkin; however, it decreased in T. asahii, T. coremiiforme, and T. faecale. Additionally, lipid droplet number was preferentially altered in Apiotrichum and Cutaneotrichosporon. These results suggested that magnesium-induced multi-septation and vacuolar area expansion phenotypically distinguish Trichosporon hyphae from Apiotrichum and Cutaneotrichosporon hyphae and distinguish C. dermatis pseudo-hyphae from Cutaneotrichosporon spp. Moreover, differences in lipid droplet size can discriminate species within Trichosporon. Our results suggest that phenotypic alteration via magnesium treatment can contribute to the characterization of Trichosporonales yeasts. These findings provide insights into fungal pathogenesis and may support new treatment strategies.IMPORTANCEMagnesium sulfate considerably affects hyphal growth and cellular organization in Trichosporon asahii. To examine the commonality of this phenotype in Trichosporonales, we treated 30 Trichosporonales yeasts with magnesium sulfate and observed genus-level phenotypic alterations. Using cell length measurement, lipid droplet staining, septum staining, and vacuole staining, considerable hyphal diversity was observed among Trichosporonales. Notably, differences in the multi-septation phenotype and vacuolar size distinguished Trichosporon hyphae from Apiotrichum and Cutaneotrichosporon hyphae and distinguished Cutaneotrichosporon dermatis from other Cutaneotrichosporon spp. Moreover, differences in lipid droplet phenotype divided Trichosporon hyphae into two groups. Our study revealed the relationship between hyphal morphology and phylogenetic systematics in Trichosporonales.

Unveiling antifungal resistance and biocide tolerance in clinical isolates of Candida spp

AIMS

Candidiasis, caused by Candida spp. is an opportunistic infection with significant healthcare risks, worsened by trends in antifungal resistance. This study aimed to evaluate the antifungal susceptibility profile, investigate resistance mechanisms, assess efflux pump activity, and examine biocide tolerance in clinical Candida isolates.

METHODS

A total of 100 Candida isolates from hospitalized and outpatient individuals were analyzed for their antifungal susceptibility profile, molecular resistance mechanisms through PCR, efflux pump activity with the Cartwheel method, and biocide tolerance (sodium hypochlorite, hydrogen peroxide, and benzalkonium chloride), which was assessed by disk diffusion.

RESULTS

A high prevalence of resistance (87%) to at least one antifungal was observed, with 47.12% of isolates showing simultaneous multiple resistance to three azole derivatives. The highest antifungal agent resistance was observed for fluconazole (n = 70) and the highest susceptibility for amphotericin B (n = 1). The most common mutation was in the ERG11 gene (n = 38/43.7%). Efflux pump activity was detected in both C. albicans and non-albicans Candida species. Biocide testing revealed a higher tolerance for sodium hypochlorite, with an inhibition zone ranging from 18.25 (4.40) to 34.0 (4.00).

CONCLUSIONS

This study highlights significant antifungal resistance in Candida spp. particularly to azoles, stressing the need for improved infection control and novel therapeutic strategies.

Resilience in Resistance: The Role of Cell Wall Integrity in Multidrug-Resistant Candida

The Candida species cell wall plays a pivotal role as a structural and functional barrier against external aggressors and as an intermediary in host-pathogen interactions. Candida species exhibit unique adaptations in their cell wall composition, with varying proportions of chitin, mannans, and β-glucans influenced by the environmental conditions and the morphological states. These components not only maintain cellular viability under osmotic, thermal, and chemical stress, but also serve as the key targets for novel antifungal strategies. MAPK signaling pathways, like the cell wall integrity pathway and the high-osmolarity glycerol pathway, play a crucial role in responding to cell wall stressors. Due to the rise of antifungal resistance and its clinical challenges, there is a need to identify new antifungal targets. This review discusses the recent advances in understanding the mechanisms underlying cell wall integrity, their impact on antifungal resistance and virulence, and their potential as therapeutic targets of C. albicans, N. glabratus, and C. auris.

Biofilm-Associated Candidiasis: Pathogenesis, Prevalence, Challenges and Therapeutic Options

The rising prevalence of fungal infections, especially those caused by Candida species, presents a major risk to global health. With approximately 1.5 million deaths annually, the urgency for effective treatment options has never been greater. Candida spp. are the leading cause of invasive infections, significantly impacting immunocompromised patients and those in healthcare settings. C. albicans, C. parapsilosis and the emerging species C. auris are categorized as highly dangerous species because of their pathogenic potential and increasing drug resistance. This review comparatively describes the formation of microbial biofilms of both bacterial and fungal origin, including major pathogens, thereby creating a novel focus. Biofilms can further complicate treatment, as these structures provide enhanced resistance to antifungal therapies. Traditional antifungal agents, including polyenes, azoles and echinocandins, have shown effectiveness, yet resistance development continues to rise, necessitating the exploration of novel therapeutic approaches. Antimicrobial peptides (AMPs) such as the anti-biofilm peptides Pom-1 and Cm-p5 originally isolated from snails represent promising candidates due to their unique mechanisms of action and neglectable cytotoxicity. This review article discusses the challenges posed by Candida infections, the characteristics of important species, the role of biofilms in virulence and the potential of new therapeutic options like AMPs.

IL-1 protects from fatal systemic candidiasis in mice by inhibiting oxidative phosphorylation and hypoxia

Invasive C. albicans infections result in high mortality rates. While IL-1 is important to combat C. albicans infections, the underlying mechanisms remain unclear. Using global and conditional Il1r1 knockouts in mice, here we show that IL-1R signaling in non-hematopoietic cells in the kidney and brain is crucial for a protective response. In the kidney, endothelial IL-1R contributes to fungal clearance independent of neutrophil recruitment, while IL-1R in hematopoietic cells is dispensable. IL-1R signaling indirectly recruits neutrophils and monocytes in the brain by regulating chemokines and adhesion molecules. Single-nucleus-RNA-sequencing data implicates excessive metabolic activity and oxidative phosphorylation across all cell types in the kidney of Il1r1-deficient mice within a few hours upon infection, with associated, localized hypoxia at infection foci. Lastly, we find that hypoxia promotes fungal growth and pathogenicity. In summary, our results show that IL-1R-signaling in non-hematopoietic cells is required to prevent fatal candidiasis by inhibiting a metabolic shift, including excessive oxidative phosphorylation and hypoxia.

Roles of P-body factors in Candida albicans filamentation and stress response

Hyphal growth is strongly associated with virulence in the human fungal pathogen Candida albicans. While hyphal transcriptional networks have been the subject of intense study, relatively little is known about post-transcriptional regulation. Previous work reported that P-Body (PB) factors Dhh1 and Edc3 were required for C. albicans virulence and filamentation, suggesting an essential role for post-transcriptional regulation of these processes. However, the molecular roles of these factors have not been determined. To further study the function of PB factors in filamentation, we generated homozygous deletions of DHH1 and EDC3 in diverse prototrophic clinical strains using transient CRISPR-Cas9. Homozygous DHH1 deletion strongly impaired growth, altered filamentation, and exhibited unusual colony morphology in response to heat stress in five strain backgrounds. Using RNA-seq, we found DHH1 deletion disrupts the regulation of thousands of genes under both yeast and hyphal growth conditions in SC5314 and P57055. This included upregulation of many stress response genes in the absence of external stress, similar to deletion of the S. cerevisiae DHH1 homolog. In contrast, we found EDC3 was not required for heat tolerance or filamentation in diverse strains. These results support a model in which DHH1, but not EDC3, represses hyphal stress response transcripts in yeast and remodels the transcriptome during filamentation. Our work supports distinct requirements for specific mRNA decay factors, bolstering evidence for post-transcriptional regulation of filamentation in C. albicans.

Roles of P-body factors in Candida albicans filamentation and stress response

Hyphal growth is strongly associated with virulence in the human fungal pathogen Candida albicans. While hyphal transcriptional networks have been the subject of intense study, relatively little is known about post-transcriptional regulation. Previous work reported that P-Body (PB) factors Dhh1 and Edc3 were required for C. albicans virulence and filamentation, suggesting an essential role for post-transcriptional regulation of these processes. However, the molecular roles of these factors have not been determined. To further study the function of PB factors in filamentation, we generated homozygous deletions of DHH1 and EDC3 in diverse prototrophic clinical strains using transient CRISPR-Cas9. Homozygous DHH1 deletion strongly impaired growth, altered filamentation, and exhibited unusual colony morphology in response to heat stress in five strain backgrounds. Using RNA-seq, we found DHH1 deletion disrupts the regulation of thousands of genes under both yeast and hyphal growth conditions in SC5314 and P57055. This included upregulation of many stress response genes in the absence of external stress, similar to deletion of the S. cerevisiae DHH1 homolog. In contrast, we found EDC3 was not required for heat tolerance or filamentation in diverse strains. These results support a model in which DHH1, but not EDC3, represses hyphal stress response transcripts in yeast and remodels the transcriptome during filamentation. Our work supports distinct requirements for specific mRNA decay factors, bolstering evidence for post-transcriptional regulation of filamentation in C. albicans.

Bio-orthogonal Labeling of Chitin in Native Pathogenic Candida Species via the Chitin Scavenge Pathway

The fungal cell wall is essential for the integrity of the cell, providing strength and shape, as well as protection against environmental stimuli. For pathogenic fungi, the cell wall is also the initial point of contact with the host. Specific cell wall features such as hypha tails and smaller glycan components modulate a wide range of fungal interactions with the immune defenses. Here, a bio-orthogonal labeling method utilizing N-acetyl-glucosamine (NAG) probes is developed to fluorescently label native, pathogenic yeast via the chitin scavenging pathway. A panel of NAG probes was assembled, synthesized, and characterized for the ability to label the chitin in pathogenic yeast. Enzymatic data show that the native scavenging biosynthetic enzyme, Hxk1, is promiscuous, permitting the labeling of the native chitin biopolymer. This chitin labeling method was validated via the development of mass spectrometry protocols. When compared to the current available labeling systems for chitin, the probes do not affect the integrity of the cell wall and do not interrupt cell growth. Furthermore, the NAG probes enabled multiple "click" platforms across pathogenic Candida species including Candida albicans and Candida tropicalis. Budding and filamentous hyphal states were observed. The results indicate the probes' utility for in vivo study of the morphological, pathogenic switch, and visualization of growth patterns. Thus, the use of these probes in pathogenic Candida strains is ideal for a variety of future applications including strain specific antifungals, diagnostic tools, and immunomodulators.

Graveyard effects of antimicrobial nanostructured titanium over prolonged exposure to drug resistant bacteria and fungi

Innovations in nanostructured surfaces have found a practical place in the medical area with use in implant materials for post-operative infection prevention. These textured surfaces should be dual purpose: (1) bactericidal on contact and (2) resistant to biofilm formation over prolonged periods. Here, hydrothermally etched titanium surfaces were tested against two highly antimicrobial resistant microbial species, methicillin-resistant Staphylococcus aureus and Candida albicans. Two surface types - unmodified titanium and nanostructured titanium - were incubated in a suspension of each microbial strain for 1 day and 7 days. Surface topography and cross-sectional information of the microbial cells adhered to the surfaces, along with biomass volume and live/dead rate, showed that while nanostructured titanium was able to kill microbes after 1 day of exposure, after 7 days, the rate of death becomes negligible when compared to the unmodified titanium. This suggests that as biofilms mature on a nanostructured surface, the cells that have lysed conceal the nanostructures and prime the surface for planktonic cells to adhere, decreasing the possibility of structure-induced lysis. Synchrotron macro-attenuated total reflection Fourier transform infrared (macro ATR-FTIR) micro-spectroscopy was used to elucidate the biochemical changes occurring following exposure to differing surface texture and incubation duration, providing further understanding into the effects of surface morphology on the biochemical molecules (lipids, proteins and polysaccharides) in an evolving and growing microbial colony.

Strategy to Identify Virulence-Related Genes of the Pathogenic Fungus Trichosporon asahii Using an Efficient Gene-Targeting System

Trichosporon asahii is a pathogenic fungus that causes severe deep-seated mycosis in immunocompromised patients with neutropenia. Understanding the molecular mechanisms of T. asahii infection will facilitate the development of new therapeutic and preventive strategies. Two main obstacles have prevented the identification of virulence-related genes in T. asahii using molecular genetic techniques: the lack of experimental animal infection models for easy evaluation of T. asahii virulence and the lack of genetic recombination technology for T. asahii. To address these issues, we developed a silkworm infection model to quantitatively evaluate T. asahii virulence and a genetic recombination method to generate gene-deficient T. asahii mutants, enabling the identification of virulence factors of T. asahii. In this review, we propose a strategy for identifying virulence-related factors in T. asahii using a silkworm infection model and an efficient gene-targeting system.

Image-based quantification of Candida albicans filamentation and hyphal length using the open-source visual programming language JIPipe

The formation of hyphae is one of the most crucial virulence traits the human pathogenic fungus Candida albicans possesses. The assessment of hyphal length in response to various stimuli, such as exposure to human serum, provides valuable insights into the adaptation strategies of C. albicans to the host environment. Despite the increasing high-throughput capacity live-cell imaging and data generation, the accurate analysis of hyphal growth has remained a laborious, error-prone, and subjective manual process. We developed an analysis pipeline utilizing the open-source visual programming language Java Image Processing Pipeline (JIPipe) to overcome the limitations associated with manual analysis of hyphal growth. By comparing our automated approach with manual analysis, we refined the strategies to achieve accurate differentiation between yeast cells and hyphae. The automated method enables length measurements of individual hyphae, facilitating a time-efficient, high-throughput, and user-friendly analysis. By utilizing this JIPipe analysis approach, we obtained insights into the filamentation behavior of two C. albicans strains when exposed to human serum albumin (HSA), the most abundant protein in human serum. Our findings indicate that despite the known role of HSA in stimulating fungal growth, it reduces filamentous growth. The implementation of our automated JIPipe analysis approach for hyphal growth represents a long-awaited and time-efficient solution to meet the demand of high-throughput data generation. This tool can benefit different research areas investigating the virulence aspects of C. albicans.

Transcriptomics analysis reveals the effect of Pulsatilla decoction butanol extract on endoplasmic reticulum and peroxisome function of Candida albicans in hyphal state

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine formula known as Pulsatilla decoction was utilized to treat conditions such as bacterial dysentery, ulcerative colitis, and fungal infections like vulvovaginal candidiasis (VVC) caused by Candida albicans (C. albicans). In our prior research, it was shown that the n-butanol extract from Pulsatilla Decoction (BEPD) exhibited effective inhibition of C. albicans. Nevertheless, the exact mechanism by which BEPD hinders hyphal growth, a critical virulence factor of C. albicans, remains unclear.

AIM OF THE STUDY

In the present study, the inhibitory effect and mechanism of the BEPD on C. albicans hyphal growth was predicted by transcriptome analysis, and further verified by in vitro and in vivo experiments.

MATERIALS AND METHODS

The BEPD was prepared and C. albicans was cultured to induce the hyphal state. Transcriptome analysis was conducted to predict the significant difference in enrichment genes and signaling pathways in the inhibitory effect of BEPD on C. albicans hyphae. Various methods, such as spot assay, time-growth curve analysis, Confocal laser scanning microscope (CLSM), scanning electron microscope (SEM), transmission electron microscope (TEM), flow cytometry, and spectrophotometer, were used to assess the effect of BEPD on hyphal structure and growth activity, lipid peroxidation level, peroxidase (CAT) activity, superoxide dismutase (SOD) activity, and apoptosis of C. albicans. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was employed to examine the expression levels of genes associated with endoplasmic reticulum and peroxisome function. The VVC model was employed to evaluate the influence of BEPD on the growth of C. albicans hyphae in vivo.

RESULT

The growth of C. albicans hyphae on solid culture media was significantly inhibited by BEPD. CLSM showed that the length of C. albicans hyphae was decreased and their vitality was lowered. SEM indicated that the hyphae of C. albicans were fractured, while TEM revealed damage to the organelles within the cells. GO enrichment and KEGG pathways analysis from transcriptomic data demonstrated that BEPD effectively suppressed the functioning of the endoplasmic reticulum and peroxisomes in C. albicans hyphae. RT-qPCR verified the decreased expression of genes associated with endoplasmic reticulum and peroxisome function by BEPD. Investigation of the endoplasmic reticulum revealed that BEPD elevated levels of reactive oxygen species (ROS) and apoptosis, indicating endoplasmic reticulum stress, as well as malondialdehyde (MDA), a marker of oxidative stress. Additionally, BEPD was shown to lower the activities of catalase (CAT) and superoxide dismutase (SOD). In animal trials, BEPD effectively hindered the growth of C. albicans hyphae in the vaginas of mice with VVC, thus reducing immune inflammatory damage to the vaginal mucosa of these mice.

CONCLUSION

This study demonstrates that BEPD has an inhibitory effect on hyphae, which are an important virulence factor of C. albicans. This effect may be related to BEPD's inhibitory effect on endoplasmic reticulum (ER) and peroxisome function. The findings suggest that BEPD could potentially play a therapeutic role in C. albicans infectious diseases by inhibiting hyphae.

Aloin remodels the cell wall of Candida albicans to reduce its hyphal virulence against oral candidiasis

Aloe vera (L.) Burm.f. is a traditional Chinese medicine known for treating various ailments, including fungal infections. Aloin is one of the major components from A. vera, but its antifungal mechanism and therapeutic potential against oral candidiasis are not clear. This study aimed to examine the mechanism of aloin against Candida albicans and its inhibitory activity against oral candidiasis. In this study, we for the first time found that aloin could induce the formation of abnormal hyphae with smaller hyphal diameters and fewer branching points in C. albicans including 11 clinical isolates without growth inhibition. The transcriptome and further cell wall contents analysis indicated that aloin remodeled the cell wall to increase the contents of β-1,3-glucan and furtherly showed an antagonistic effect with micafungin. Aloin also significantly inhibited the cell damage of oral epithelial cells and oral candidiasis in mice infected by C. albicans due to its inhibitory actions on the hyphal development and expressions of virulence factors, including candidalysin (coded by ECE1). Our results suggest that aloin is a promising antifungal agent for controlling candidiasis and targeting hyphal development and pathogenesis represents a practical strategy for developing new antifungal drugs. KEY POINTS: • Aloin remodels the C. albicans cell wall to form avirulent hyphae. • Aloin inhibits C. albicans infections in oral epithelial cells and mouse mucosa without toxicity. • Aloin is a promising antifungal agent with therapeutic potential against C. albicans infections.

Gelatin Nanoemulsion-Based Co-Delivery of Terbinafine and Essential Oils for Treatment of Candida albicans Biofilms

Fungal infections represent a significant global health challenge. Candida albicans is a particularly widespread pathogen, with both molecular and biofilm-based mechanisms making it resistant to or tolerant of available antifungal drugs. This study reports a combination therapy, active against C. albicans, utilizing terbinafine and essential oils incorporated into a gelatin-based nanoemulsion system (T-GNE). Eugenol and methyl eugenol/terbinafine T-GNEs had an additive efficacy, while carvacrol (CT-GNE) worked synergistically with terbinafine, providing effective antifungal treatment with minimal mammalian cell toxicity. Confocal microscopy demonstrated that CT-GNE penetrated the dense C. albicans biofilm and disrupted the fungal cell membrane. Overall, the combination of essential oils with terbinafine in GNE provided a promising treatment for fungal biofilms.

Current Updates on Pathogenesis, Systemic Therapy, and Treatment of Invasive Fungal Infections

Numerous health hazards are associated with fungal infections, ranging from asymptomatic cases to potentially fatal invasive diseases that are especially dangerous for those with impaired immune systems. The main causes behind these diseases are opportunistic fungi, namely Aspergillus, Candida, and Cryptococcus. Invasive fungal infections (IFIs) require a global response that includes the development of vaccines, standardized protocols for diagnosis, potent antifungal medications, and strategies to stop drug-resistant strains. Improving high-risk group diagnosis and treatment is essential to lowering death rates. This review highlights the substantial health concerns associated with fungal infections, especially in immunocompromised individuals, and identifies Aspergillus, Candida, and Cryptococcus as the main pathogens. It highlights the necessity of international efforts, such as the development of novel diagnostic instruments, imaging methods, and antifungal drugs, to combat these invasive infections. The review also addresses the increasing need for novel treatment approaches in light of the developing resistance to widely used antifungal medications. Furthermore, the significance of secretory proteins in fungal pathogenicity and the potential of combination therapy are investigated. It is also suggested that a multimodal strategy be used to fight these illnesses, given the promise of multivalent vaccinations. Overall, this study emphasizes how critical it is to develop better diagnostic and treatment strategies in order to successfully control and lessen the impact of invasive fungal diseases on the health of the world.

Antimicrobial Peptides: A Promising Alternative to Conventional Antimicrobials for Combating Polymicrobial Biofilms

Polymicrobial biofilms adhere to surfaces and enhance pathogen resistance to conventional treatments, significantly contributing to chronic infections in the respiratory tract, oral cavity, chronic wounds, and on medical devices. This review examines antimicrobial peptides (AMPs) as a promising alternative to traditional antibiotics for treating biofilm-associated infections. AMPs, which can be produced as part of the innate immune response or synthesized therapeutically, have broad-spectrum antimicrobial activity, often disrupting microbial cell membranes and causing cell death. Many specifically target negatively charged bacterial membranes, unlike host cell membranes. Research shows AMPs effectively inhibit and disrupt polymicrobial biofilms and can enhance conventional antibiotics' efficacy. Preclinical and clinical research is advancing, with animal studies and clinical trials showing promise against multidrug-resistant bacteria and fungi. Numerous patents indicate increasing interest in AMPs. However, challenges such as peptide stability, potential cytotoxicity, and high production costs must be addressed. Ongoing research focuses on optimizing AMP structures, enhancing stability, and developing cost-effective production methods. In summary, AMPs offer a novel approach to combating biofilm-associated infections, with their unique mechanisms and synergistic potential with existing antibiotics positioning them as promising candidates for future treatments.

Antifungal activity of essential oils and their potential synergistic effect with amphotericin B

Candida albicans is a common opportunistic pathogen, causing infections ranging from superficial to bloodstream infections. The limited antifungal options and rising drug resistance challenge clinical treatment. We screened 98 essential oils and identified 48 with antifungal activity against Candida albicans at 1% concentration, determining their minimum inhibitory concentrations (MIC). Of these, 14 maintained fungicidal activity at lower concentrations (0.25% and 0.125%). 5 essential oils (Cinnamon, Satureja montana, Palmarosa, Lemon eucalyptus, and Honey myrtle) showed the highest inhibitory effects on stationary-phase Candida albicans and inhibited hyphae elongation. Synergistic effects were observed when combining Palmarosa with amphotericin B (AmB) against growing-phase Candida albicans, while Cinnamon and Satureja montana with AmB showed superior efficacy against stationary-phase infections. We identified the active components of 5 essential oils using gas chromatography-mass spectrometry (GC-MS) and found the following main constituents: Cinnamon primarily contains benzyl benzoate and eugenol, Satureja montana is dominated by carvacrol and cymene, Palmarosa features geraniol and geranyl acetate, Lemon eucalyptus includes dl-Isopulegol and citronellal, and Honey myrtle is characterized by citral and neral. Our results may aid in developing more effective antifungal treatments.

Ellagic Acid Potentiates the Inhibitory Effects of Fluconazole Against Candida albicans

Background/Objectives: Antifungal resistance to azoles, coupled with the increasing prevalence of Candida albicans infections, represents a significant public health challenge and has driven the search for new natural compounds that can act as alternatives or adjuvants to the current antifungals. Ellagic acid (EA) has demonstrated antifungal activity; however, its effects are not fully understood. In this study, we investigated the in vitro anti-Candida activity of EA and its ability to potentiate the effects of fluconazole (FLZ) on C. albicans.Methods: The Minimum Inhibitory Concentration (MIC) of EA was determined by broth microdilution and its interaction with FLZ was assessed using a checkerboard assay. Additionally, we examined the effects of EA on yeast-to-hypha transition, inhibition of biofilm formation, time-kill kinetics, hemolytic activity, and cytotoxicity in HeLa ATCC® CCL-2™ cells. Results: EA exhibited MIC values ranging from 250 to 2000 µg/mL and showed synergistic and additive interactions with FLZ, resulting in a marked reduction in the MIC values of FLZ (up to 32-fold) and EA (up to 16-fold). In the time-kill assay, the most effective combinations were 4× EA MIC, 2× EA MIC, and FIC EA + FLZ, which showed fungicidal activity. Furthermore, EA did not show hemolytic activity and demonstrated low and dose-dependent cytotoxicity in HeLa cells, with no cytotoxic effects observed in combination with FLZ. EA and the synergistic combination of EA and FLZ interfered with both the yeast-to-hypha transition process in C. albicans cells and biofilm formation. In addition to its antifungal efficacy, EA demonstrated a favorable safety profile at the concentrations used. Conclusions: This study presents promising results regarding the potential use of EA in combination with FLZ for the treatment of C. albicans infections.

Fungal symbiont transmitted by free-living mice promotes type 2 immunity

The gut mycobiota is crucial for intestinal homeostasis and immune function1. Yet its variability and inconsistent fungal colonization of laboratory mice hinders the study of the evolutionary and immune processes that underpin commensalism2,3. Here, we show that Kazachstania pintolopesii is a fungal commensal in wild urban and rural mice, with an exceptional ability to colonize the mouse gastrointestinal tract and dominate the gut mycobiome. Kazachstania pintolopesii colonization occurs in a bacteria-independent manner, results in enhanced colonization resistance to other fungi and is shielded from host immune surveillance, allowing commensal presence. Following changes in the mucosal environment, K. pintolopesii colonization triggers a type 2 immune response in mice and induces gastrointestinal eosinophilia. Mechanistically, we determined that K. pintolopesii activates type 2 immunity via the induction of epithelial IL-33 and downstream IL-33-ST2 signalling during mucus fluctuations. Kazachstania pintolopesii-induced type 2 immunity enhanced resistance to helminth infections or aggravated gastrointestinal allergy in a context-dependent manner. Our findings indicate that K. pintolopesii is a mouse commensal and serves as a valuable model organism for studying gut fungal commensalism and immunity in its native host. Its unnoticed presence in mouse facilities highlights the need to evaluate its influence on experimental outcomes and phenotypes.

The identification of essential cellular genes is critical for validating drug targets

Accurately identifying biological targets is crucial for advancing treatment options. Essential genes, vital for cell or organism survival, hold promise as potential drug targets in disease treatment. Although many studies have sought to identify essential genes as therapeutic targets in medicine and bioinformatics, systematic reviews on their relationship with drug targets are relatively rare. This work presents a comprehensive analysis to aid in identifying essential genes as potential targets for drug discovery, encompassing their relevance, identification methods, successful case studies, and challenges. This work will facilitate the identification of essential genes as therapeutic targets, thereby boosting new drug development.

In Vitro Acid Resistance of Pathogenic Candida Species in Simulated Gastric Fluid

Background and Aims

Although species in the fungal genus Candida are often commensal residents of the gastrointestinal (GI) tract, they can also cause high-mortality systemic candidiasis. Most pathogenic Candida species are dimorphic fungi that exist predominantly in filamentous forms in the invading tissues. Candida albicans is the most prominent pathogen among Candida species, but nonalbicans Candida species have also emerged as important pathogens. The stomach is the most acidic niche in the GI tract and is maintained at pH 1-2 in healthy individuals. The aim of the present study was to determine whether Candida species can survive in gastric fluid and to observe their morphology under varied pH conditions.

Methods

We investigated the in vitro survival of the pathogenic Candida species C. albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis in simulated gastric fluid.

Results

We first described that a portion of the 4 Candida species can survive under highly acidic conditions. Moreover, dimorphic Candida species, namely, C. albicans, C. parapsilosis, and C. tropicalis, exhibited yeast-hyphal transition in simulated gastric fluid with elevated pH. Pathogenic filamentous cells had lower acid resistance than yeast cells.

Conclusion

These findings may illuminate the migration to the lower GI tract by commensal fungi of the oral cavity.

Highly conducting Laser-Induced Graphene-Ag nanoparticle composite as an effective supercapacitor electrode with anti-fungal properties

This study presents a simple and an environmentally friendly approach to make Laser-Induced Graphene (LIG) based supercapacitor electrodes anchored with abundant Silver Nanoparticles (AgNPs). LIG, was synthesized using a CO2 laser writing technique on polyimide substrate. The LIG-Ag composite was prepared using two techniques, drop-coating, and screen-printing. Ag nanoparticles prepared using the plant extract of Swietenia Macrophylla was utilized to drop-coat AgNP on LIG substrate. Screen-printing was done by using a commercial Ag-ink and a suitable mesh. The supercapacitor made from screen-printed electrodes and supercapacitor made form drop-coated electrodes showed a high specific capacitance of 118 mF/cm2, 38 mF/cm2, and a high energy density of 2.42 mWh/cm2, 0.05 mWh/cm2 respectively. The screen-printed composite of LIG and AgNP was further studied for its anti-fungal properties and proved to be effective against Candida sp.

Hyphal swelling induced in the phagosome of macrophages

Macrophages play critical protective roles as sentinels of the innate immune system against fungal infection. It is therefore important to understand the dynamics of the interaction between these phagocytes and their fungal prey. We show here that many of the hyphal apices formed by Candida albicans within the macrophage ceased elongating, and apical and sub-apical hyphal compartments became swollen. Swollen hyphal cell compartments assimilated less Lysotracker-Red than non-swollen compartments, suggesting they had enhanced viability. Staining with florescent dyes suggested that there were higher levels of β-glucan and chitin in internalized fungal filaments compared to non-internalized hyphae, suggesting active cell wall remodelling within macrophages. These observations suggest that the stresses imposed by macrophages upon the fungus lead to changes in cell wall composition, inhibition of polarised growth and the induction of swelling in hyphal compartments, and that this can prevent or delay loss of viability of hyphal cells within the phagocyte.

Antifungal bioactivity of Sarcococca hookeriana var. digyna Franch. against fluconazole-resistant Candida albicans in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Sarcococca hookeriana var. digyna Franch. has been widely utilized in folk medicine by the Miao people in the southwestern region of China for treating skin sores which may be associated with microbial infection.

AIM OF THE STUDY

To investigate the antifungal bioactivity of S. hookeriana var. digyna against fluconazole-resistant Candida albicans in vitro and in vivo, as well as its underlying mechanism and the key bioactive component.

MATERIALS AND METHODS

The antifungal bioactivity of 80% ethanol extract of S. hookeriana var. digyna (SHE80) was investigated in vitro using the broth microdilution method, time-growth curve, and time-kill assay. Its key functional component and antifungal mechanism were explored with combined approaches including UPLC-Q-TOF-MS, network pharmacology and metabolomics. The antifungal pathway was further supported via microscopic observation of fungal cell morphology and examination of its effects on fungal biofilm and cell membranes using fluorescent staining reagents. In vivo assessment of antifungal bioactivity was conducted using a mouse model infected with C. albicans on the skin.

RESULTS

S. hookeriana var. digyna suppressed fluconazole-resistant C. albicans efficiently (MIC = 16 μg/mL, MFC = 64 μg/mL). It removed fungal biofilm, increased cell membrane permeability, induced protein leakage, reduced membrane fluidity, disrupted mitochondrial membrane potential, induced the release of reactive oxygen species, promoted cell apoptosis, and inhibited the transformation of fungi from the yeast state to the hyphal state significantly. In terms of mechanism, it affected sphingolipid metabolism and signaling pathway. Moreover, the predicted bioactive component, sarcovagine D, was supported by antifungal bioactivity evaluation in vitro (MIC = 4 μg/mL, MFC = 16 μg/mL). Furthermore, S. hookeriana var. digyna promoted wound healing, reduced the number of colony-forming units, and reduced inflammation effectively in vivo.

CONCLUSIONS

The traditional use of S. hookeriana var. digyna for fungal skin infections was supported by antifungal bioactivity investigated in vitro and in vivo. Its mechanism and bioactive component were predicted and confirmed by experiments, which also provided a new antifungal agent for future research.

Candida albicans Induces Oral Microbial Dysbiosis and Promotes Oral Diseases

Candida albicans are ubiquitous fungal organisms that colonize the oral cavity of healthy individuals without causing disease. C. albicans is an opportunistic microorganism with several virulent factors that influence the inflammatory process and allow it to invade tissues, evade host defense mechanisms, and release toxins, facilitating proliferation and degradation. At present, increasing emphasis is placed on polymicrobial interactions between C. albicans and various bacterial pathogens. Such interaction is mutually beneficial for both parties: it is competitive and antagonistic. Their complex interaction and colonization in the oral cavity serve as the basis for several oral diseases. The dispersion of C. albicans in saliva and the systemic circulation is noted in association with other bacterial populations, suggesting their virulence in causing disease. Hence, it is necessary to understand fungal-bacterial interactions for early detection and the development of novel therapeutic strategies to treat oral diseases. In this paper, we review the mutualistic interaction of C. albicans in oral biofilm formation and polymicrobial interactions in oral diseases. In addition, C. albicans virulence in causing biofilm-related oral diseases and its presence in saliva are discussed.

Benzyldimethyldodecyl Ammonium Chloride-Doped Denture-Based Resin: Impact on Strength, Surface Properties, Antifungal Activities, and In Silico Molecular Docking Analysis

Candida albicans (C. albicans) adhering to denture-based resins (DBRs) is a known cause of denture stomatitis. A new approach to prevent denture stomatitis is to include antimicrobial substances within DBRs. Here, we examined the mechanical performance and antifungal properties of DBRs containing benzyldimethyldodecyl ammonium chloride (C12BDMA-Cl) as an antimicrobial compound. C12BDMA-Cl is a quaternary ammonium compound, and its antifungal properties have never been investigated when combined with dental acrylic resin. Therefore, we modified a commercially available heat-polymerized acrylic DBR to contain 3 and 5 wt.% of C12BDMA-Cl. Unmodified DBR was used as a control group. Specimens were prepared using the conventional heat processing method. The specimen's flexural strength, elastic modulus, microhardness, and surface roughness were evaluated. C. albicans biofilm was grown on the specimens and assessed via colony-forming units (CFUs) and scanning electron microscopy (SEM). In silico molecular docking was applied to predict the potential C12BDMA-Cl inhibition activity as an antifungal drug. The 3% C12BDMA-Cl DBR demonstrated antifungal activities without a deterioration effect on the mechanical performance. SEM images indicated fewer colonies in DBR containing C12BDMA-Cl, which can be a potential approach to managing denture stomatitis. In conclusion, C12BDMA-Cl is a promising antifungal agent for preventing and treating denture stomatitis.

Gain- and loss-of-function alleles within signaling pathways lead to phenotypic diversity among individuals

Understanding how phenotypic diversity is generated is an important question in biology. We explored phenotypic diversity among wild yeast isolates (Saccharomyces cerevisiae) and found variation in the activity of MAPK signaling pathways as a contributing mechanism. To uncover the genetic basis of this mechanism, we identified 1957 SNPs in 62 candidate genes encoding signaling proteins from a MAPK signaling module within a large collection of yeast (>1500 individuals). Follow-up testing identified functionally relevant variants in key signaling proteins. Loss-of-function (LOF) alleles in a PAK kinase impacted protein stability and pathway specificity decreasing filamentous growth and mating phenotypes. In contrast, gain-of-function (GOF) alleles in G-proteins that were hyperactivating induced filamentous growth. Similar amino acid substitutions in G-proteins were identified in metazoans that in some cases were fixed in multicellular lineages including humans, suggesting hyperactivating GOF alleles may play roles in generating phenotypic diversity across eukaryotes. A mucin signaler that regulates MAPK activity was also found to contain a prevalance of presumed GOF alleles amoung individuals based on changes in mucin repeat numbers. Thus, genetic variation in signaling pathways may act as a reservoir for generating phenotypic diversity across eukaryotes.

A novel pH-responsive monomer inhibits Candida albicans via a dual antifungal mode of action

The scarcity of the antifungal drug arsenal highlights an urgent need to develop alternative treatments for candidiasis caused by Candida albicans (C. albicans). As pH is closely associated with C. albicans infection, it could be an essential target in a novel approach for designing antifungal therapy. In this study, a novel intelligent antifungal monomer, dodecylmethylaminoethyl methacrylate (DMAEM), with a pH-responsive tertiary amine group and a methacrylate-derived CC double bond group is developed. It is uncovered that the two functional groups of DMAEM contribute to a dual mode of action. Under acidic pH, the tertiary amine of DMAEM protonates into a cationic fungicide, sharing similar structural and functional characteristics with quaternary ammonium salts, which exerts fungicidal activity by targeting the CHK1 two-component system in C. albicans. At neutral pH, the methacrylate-derived CC double bond group contributes to anti-virulence activity by blocking hyphal formation. In addition, it is also identified that DMAEM suppresses filamentation by altering the extracellular vesicles of C. albicans. These findings support that the novel intelligent pH-responsive monomer could be a therapeutic candidate for treating candidiasis.

Conserved signaling modules regulate filamentous growth in fungi: a model for eukaryotic cell differentiation

Eukaryotic organisms are composed of different cell types with defined shapes and functions. Specific cell types are produced by the process of cell differentiation, which is regulated by signal transduction pathways. Signaling pathways regulate cell differentiation by sensing cues and controlling the expression of target genes whose products generate cell types with specific attributes. In studying how cells differentiate, fungi have proved valuable models because of their ease of genetic manipulation and striking cell morphologies. Many fungal species undergo filamentous growth-a specialized growth pattern where cells produce elongated tube-like projections. Filamentous growth promotes expansion into new environments, including invasion into plant and animal hosts by fungal pathogens. The same signaling pathways that regulate filamentous growth in fungi also control cell differentiation throughout eukaryotes and include highly conserved mitogen-activated protein kinase (MAPK) pathways, which is the focus of this review. In many fungal species, mucin-type sensors regulate MAPK pathways to control filamentous growth in response to diverse stimuli. Once activated, MAPK pathways reorganize cell polarity, induce changes in cell adhesion, and promote the secretion of degradative enzymes that mediate access to new environments. However, MAPK pathway regulation is complicated because related pathways can share components with each other yet induce unique responses (i.e. signal specificity). In addition, MAPK pathways function in highly integrated networks with other regulatory pathways (i.e. signal integration). Here, we discuss signal specificity and integration in several yeast models (mainly Saccharomyces cerevisiae and Candida albicans) by focusing on the filamentation MAPK pathway. Because of the strong evolutionary ties between species, a deeper understanding of the regulation of filamentous growth in established models and increasingly diverse fungal species can reveal fundamentally new mechanisms underlying eukaryotic cell differentiation.

A one-pot five component reaction for the synthesis of tetrazol-benzofuran hybrids and their inhibitory activity against Mucor lusitanicus

A synthetic strategy for obtaining a new series of 1,5-disubstituted tetrazole-benzofuran hybrid systems via a one-pot five-component reaction is described. This process involves a Ugi-azide multicomponent reaction coupled to an intramolecular cyclization catalyzed by Pd/Cu, resulting in low to moderate yields from 21 to 67%. This protocol allowed the synthesis of highly substituted benzofurans at the 2-position through an operationally simple process under mild reaction conditions and with high bond forming efficiency due to the formation of six new bonds (two C-C, two C-N, one N-N, and one C-O). Besides, to evaluate the antifungal activity of 1,5-disubstituted tetrazole-benzofurans 9a-n, in vitro studies against Mucor lusitanicus were performed, finding that compound 9b exhibits bioactivity comparable to the commercial antifungal drug Amphotericin B. These results suggest potential for use in controlling mucormycosis infections in animal models, highlighting the importance of these findings given the limited antifungal drug options and high mortality rates associated with this infection.

Synthesis and antifungal evaluation of novel triazole derivatives bearing a pyrazole-methoxyl moiety

Life-threatening invasive fungal infections pose a serious threat to human health. A series of novel triazole derivatives bearing a pyrazole-methoxyl moiety were designed and synthesized in an effort to obtain antifungals with potent, broad-spectrum activity that are less susceptible to resistance. Most of these compounds exhibited moderate to excellent in vitro antifungal activities against Candida albicans SC5314 and 10,231, Cryptococcus neoformans 32,609, Candida glabrata 537 and Candida parapsilosis 22,019 with minimum inhibitory concentration (MIC) values of ≤0.125 μg/mL to 0.5 μg/mL. Use of recombinant Saccharomyces cerevisiae strains showed compounds 7 and 10 overcame the overexpression and resistant-related mutations in ERG11 of S. cerevisae and several pathogenic Candida spp. Despite being substrates of the C. albicans and Candida auris Cdr1 drug efflux pumps, compounds 7 and 10 showed moderate potency against five fluconazole (FCZ)-resistant fungi with MIC values from 2.0 μg/mL to 16.0 μg/mL. Growth kinetics confirmed compounds 7 and 10 had much stronger fungistatic activity than FCZ. For C. albicans, compounds 7 and 10 inhibited the yeast-to-hyphae transition, biofilm formation and destroyed mature biofilm more effectively than FCZ. Preliminary mechanism of action studies showed compounds 7 and 10 blocked the ergosterol biosynthesis pathway at Erg11, ultimately leading to cell membrane disruption. Further investigation of these novel triazole derivatives is also warranted by their predicted ADMET properties and low cytotoxicity.

Novel targets and improved immunotherapeutic techniques with an emphasis on antimycosal drug resistance for the treatment and management of mycosis

Infections due to pathogenic fungi are endemic in particular area with increased morbidity and mortality. More than a thousand people are infected per year and the way of treatment is of high demand having a significant impact on the population health. Medical practitioners confront various troublesome analytic and therapeutical challenges in the administration of immunosuppressed sufferer at high danger of expanding fungal infections. An upgraded antimycosal treatment is fundamental for a fruitful result while treating intrusive mycoses. A collection of antimycosal drugs keeps on developing with their specific antifungal targets including cell membrane, mitochondria, cell wall, and deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) or protein biosynthesis. Some fundamental classes of ordinarily directed medications are the polyenes, amphotericin B, syringomycin, allylamines, honokiol, azoles, flucytosine, echinocandins etc. However, few immunotherapy processes and vaccinations are being developed to mark this need, although one presently can't seem to arrive at the conclusion. In this review article, there has been a trial to give details upgradation about the current immune therapeutic techniques and vaccination strategies against prevention or treatment of mycosis as well as the difficulties related with their turn of events. There has been also a visualization in the mentioned review paper about the various assorted drugs and their specific target analysis along with therapeutic interventions.

Synergistic in vitro activity and mechanism of KBN lotion and miconazole nitrate against drug-resistant Candida albicans biofilms

Background

In the face of increasing antifungal resistance among Candida albicans biofilms, this study explores the efficacy of a combined treatment using Kangbainian lotion (KBN) and miconazole nitrate (MN) to address this challenge.

Methods

Using UPLC-Q-TOF/MS Analysis for Identification of Active Compounds in KBN Lotion; FICI for synergy evaluation, XTT and ROS assays for biofilm viability and oxidative stress, fluorescence and confocal laser scanning microscopy (CLSM) for structural and viability analysis, and real-time fluorescence for gene expression.

Conclusion

Our study indicates that the combined application of KBN and MN somewhat impacts the structural integrity of Candida albicans biofilms and affects the expression of several key genes involved in biofilm formation, including ALS1, ALS3, HWP1, HSP90, and CSH1. These preliminary findings suggest that there may be a synergistic effect between KBN and MN, potentially influencing not only the structural aspects of fungal biofilms but also involving the modulation of genetic pathways during their formation.

Bioorthogonal labeling of chitin in pathogenic Candida species reveals biochemical mechanisms of hyphal growth and homeostasis

Pathogenic fungi rely on the cell wall component, chitin, for critical structural and immunological functions. Here a chitin labeling method to visualize the hyphal pathogenic response was developed. The data show that filamentous fungi, Candida albicans , transport N -acetylglucosamine (NAG) bio-orthogonal probes and incorporate them into the cell wall, indicating the probes utility for in vivo study of the morphological, pathogenic switch. As yeast reside in complex microenvironments, The data show that the opportunistic microbe C. albicans , has developed processes to utilize surrounding bacterial cell wall fragments to initiate the morphogenic switch. The probes are utilized for visualization of growth patterns of pathogenic fungi, providing insights into novel mechanisms for the development of antifungals. Remodeling chitin in fungi using NAG derivatives will advance yeast pathogenic studies.

Inhibition of Development and Metabolism of Dual-Species Biofilms of Candida albicans and Candida krusei (Pichia kudriavzevii) by Organoselenium Compounds

Although Candida albicans is the most frequently identified Candida species in clinical settings, a significant number of infections related to the non-albicans Candida (NAC) species, Candida krusei, has been reported. Both species are able to produce biofilms and have been an important resistance-related factor to antimicrobial resistance. In addition, the microbial relationship is common in the human body, contributing to the formation of polymicrobial biofilms. Considering the great number of reports showing the increase in cases of resistance to the available antifungal drugs, the development of new and effective antifungal agents is critical. The inhibitory effect of Organoselenium Compounds (OCs) on the development of Candida albicans and Candida krusei was recently demonstrated, supporting the potential of these compounds as efficient antifungal drugs. In addition, OCs were able to reduce the viability and the development of biofilms, a very important step in colonization and infection caused by fungi. Thus, the objective of this study was to investigate the effect of the Organoselenium Compounds (p-MeOPhSe)2, (PhSe)2, and (p-Cl-PhSe)2 on the development of dual-species biofilms of Candida albicans and Candida krusei produced using either RPMI-1640 or Sabouraud Dextrose Broth (SDB) media. The development of dual-species biofilms was evaluated by the determination of both metabolic activity, using a metabolic assay based on the reduction of XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt) assay and identification of either Candida albicans and Candida krusei on CHROMagar Candida medium. Biofilm formation using RPMI-1640 was inhibited in 90, 55, and 20% by 30 µM (p-MeOPhSe)2, (PhSe)2, and (p-Cl-PhSe)2, respectively. However, biofilms produced using SDB presented an inhibition of 62, 30 and 15% in the presence of 30 µM (p-MeOPhSe)2, (PhSe)2, and (p-Cl-PhSe)2, respectively. The metabolic activity of 24 h biofilms was inhibited by 35, 30 and 20% by 30 µM (p-MeOPhSe)2, (PhSe)2, and (p-Cl-PhSe)2, respectively, with RPMI-1640; however, 24 h biofilms formed using SDB were not modified by the OCs. In addition, a great reduction in the number of CFUs of Candida albicans (93%) in biofilms produced using RPMI-1640 in the presence of 30 µM (p-MeOPhSe)2 was observed. However, biofilms formed using SDB and treated with 30 µM (p-MeOPhSe)2 presented a reduction of 97 and 69% in the number of CFUs of Candida albicans and Candida krusei, respectively. These results demonstrated that Organoselenium Compounds, mainly (p-MeOPhSe)2, are able to decrease the metabolic activity of dual-species biofilms by reducing both Candida albicans and Candida krusei cell number during biofilm formation using either RPMI-1640 or SDB. Taken together, these results demonstrated the potential of the OCs to inhibit the development of dual-species biofilms of Candida albicans and Candida krusei.

Bacillus coagulans LMG S-24828 Impairs Candida Virulence and Protects Vaginal Epithelial Cells against Candida Infection In Vitro

Probiotics are living microbes that provide benefits to the host. The growing data on health promotion, following probiotics administration, increased interest among researchers and pharmaceutical companies. Infections of the lower genital tract in females, caused by a wide range of pathogens, represent one of the main areas for the use of probiotics and postbiotics. Vulvovaginal candidiasis (VVC) affects 75% of women of reproductive age at least once during their lifetime, with 5-8% developing the recurrent form (RVVC). The disease is triggered by the overgrowth of Candida on the vaginal mucosa. Here, in order to establish its probiotic potential in the context of VVC, we evaluated the anti-fungal effects of the spore-producing Bacillus coagulans LMG S-24828 against C. albicans and C. parapsilosis as well as its beneficial effects in counteracting Candida vaginal infection in vitro. Our results show that both live B. coagulans and its Cell-Free Supernatant (CFS) exerted antifungal activity against both fungi. Moreover, live B. coagulans reduced hyphal formation, inhibited C. albicans adhesion to vaginal epithelial cells, showed co-aggregation capacity, and exerted a protective effect on vaginal epithelial cells infected with C. albicans. These data suggest that B. coagulans LMG S-24828 may provide benefits in the context of Candida vaginal infections.

Life on a leaf: the epiphyte to pathogen continuum and interplay in the phyllosphere

Epiphytic microbes are those that live for some or all of their life cycle on the surface of plant leaves. Leaf surfaces are a topologically complex, physicochemically heterogeneous habitat that is home to extensive, mixed communities of resident and transient inhabitants from all three domains of life. In this review, we discuss the origins of leaf surface microbes and how different biotic and abiotic factors shape their communities. We discuss the leaf surface as a habitat and microbial adaptations which allow some species to thrive there, with particular emphasis on microbes that occupy the continuum between epiphytic specialists and phytopathogens, groups which have considerable overlap in terms of adapting to the leaf surface and between which a single virulence determinant can move a microbial strain. Finally, we discuss the recent findings that the wheat pathogenic fungus Zymoseptoria tritici spends a considerable amount of time on the leaf surface, and ask what insights other epiphytic organisms might provide into this pathogen, as well as how Z. tritici might serve as a model system for investigating plant-microbe-microbe interactions on the leaf surface.

Hemiprotonic ph-ph+ with two targets inhibits metastatic breast cancer and concurrent candidiasis

Concurrent infection in breast cancer patients is the direct cause of the high mortality rate of the disease. However, there is no available method to increase the survival rate until now. To address the problem, we propose one drug with two target strategy to treat the refractory disease. A small chemical, ph-ph+, was attempted to be used in the study to explore the feasibility of the approach in anticancer and antifungus at the same time. The results showed that ph-ph+ could prevent the proliferation and metastasis of breast cancer cells, and kill C. albicans simultaneously. The molecular mechanism was associated with the activation of an evolutionarily conserved protease CLpP in the cancer and C. albicans cells. Also, the signaling pathway mediated by PLAGL2 that highly expressed in cancer cells participated in preventing cell metastasis and inducing apoptosis of ph-ph+. The one drug with dual targets inhibited the growth and metastasis of the cancer cells, and meanwhile eliminated C. albicans in tissues in the experimental animals. The results suggested that ph-ph+ with dual targets of CLpP and PLAGL2 would be a feasible approach to prolong the survival rate in patients with metastatic breast cancer and pathogenic infection.

Quantification methods of Candida albicans are independent irrespective of fungal morphology

The ability of Candida albicans to switch its morphology from yeast to filaments, known as polymorphism, may bias the methods used in microbial quantification. Here, we compared the quantification methods [cell/mL, colony forming units (CFU)/mL, and the number of nuclei estimated by viability polymerase chain reaction (vPCR)] of three strains of C. albicans (one reference strain and two clinical isolates) grown as yeast, filaments, and biofilms. Metabolic activity (XTT assay) was also used for biofilms. Comparisons between the methods were evaluated by agreement analyses [Intraclass and Concordance Correlation Coefficients (ICC and CCC, respectively) and Bland-Altman Plot] and Pearson Correlation (α = 0.05). Principal Component Analysis (PCA) was employed to visualize the similarities and differences between the methods. Results demonstrated a lack of agreement between all methods irrespective of fungal morphology/growth, even when a strong correlation was observed. Bland-Altman plot also demonstrated proportional bias between all methods for all morphologies/growth, except between CFU/mL X vPCR for yeasts and biofilms. For all morphologies, the correlation between the methods were strong, but without linear relationship between them, except for yeast where vPCR showed weak correlation with cells/mL and CFU/mL. XTT moderately correlated with CFU/mL and vPCR and weakly correlated with cells/mL. For all morphologies/growth, PCA showed that CFU/mL was similar to cells/mL and vPCR was distinct from them, but for biofilms vPCR became more similar to CFU/mL and cells/mL while XTT was the most distinct method. As conclusions, our investigation demonstrated that CFU/mL underestimated cells/mL, while vPCR overestimated both cells/mL and CFU/mL, and that the methods had poor agreement and lack of linear relationship, irrespective of C. albicans morphology/growth.1.

Exploring the role of candidalysin in the pathogenicity of Candida albicans by gene set enrichment analysis and evolutionary dynamics

AIMS

To explore the pathogenic mechanisms of Candida albicans (C. albicans), focusing on its impact on human health, particularly through invasive infections in the gastrointestinal and respiratory tracts.

METHODS

In this study, we evaluated the demographic and clinical profiles of 7 pneumonia patients. Meanwhile, we used Gene Set Enrichment Analysis (GSEA) and Evolutionary Dynamics method to analyze the role of candidalysin in C. albicans pathogenicity.

RESULTS

By analyzing genomic data and conducting biomedical text mining, we identified novel mutation sites in the candidalysin coding gene ECE1-III, shedding light into the genetic diversity within C. albicans strains and their potential implications for antifungal resistance. Our results revealed significant associations between C. albicans and respiratory as well as gastrointestinal diseases, emphasizing the fungus's role in the pathogenesis of these diseases. Additionally, we identified a new mutation site in the C. albicans strain YF2-5, isolated from patients with pneumonia. This mutation may be associated with its heightened pathogenicity.

CONCLUSION

Our research advances the understanding of C. albicans pathogenicity and opens new avenues for developing targeted antifungal therapies. By focusing on the molecular basis of fungal virulence, we aim to contribute to the development of more effective treatment strategies, addressing the challenge of multidrug resistance in invasive fungal infections.

To each its own: Mechanisms of cross-talk between GPI biosynthesis and cAMP-PKA signaling in Candida albicans versus Saccharomyces cerevisiae

Candida albicans is an opportunistic fungal pathogen that can switch between yeast and hyphal morphologies depending on the environmental cues it receives. The switch to hyphal form is crucial for the establishment of invasive infections. The hyphal form is also characterized by the cell surface expression of hyphae-specific proteins, many of which are GPI-anchored and important determinants of its virulence. The coordination between hyphal morphogenesis and the expression of GPI-anchored proteins is made possible by an interesting cross-talk between GPI biosynthesis and the cAMP-PKA signaling cascade in the fungus; a parallel interaction is not found in its human host. On the other hand, in the nonpathogenic yeast, Saccharomyces cerevisiae, GPI biosynthesis is shut down when filamentation is activated and vice versa. This too is achieved by a cross-talk between GPI biosynthesis and cAMP-PKA signaling. How are diametrically opposite effects obtained from the cross-talk between two reasonably well-conserved pathways present ubiquitously across eukarya? This Review attempts to provide a model to explain these differences. In order to do so, it first provides an overview of the two pathways for the interested reader, highlighting the similarities and differences that are observed in C. albicans versus the well-studied S. cerevisiae model, before going on to explain how the different mechanisms of regulation are effected. While commonalities enable the development of generalized theories, it is hoped that a more nuanced approach, that takes into consideration species-specific differences, will enable organism-specific understanding of these processes and contribute to the development of targeted therapies.

Propensity of Candida spp. prosthetic joint infection clinical isolates to form aggregates in synovial fluid and the clinical ramifications

BACKGROUND

Bacterial aggregation has been shown to occur in synovial fluid which are resistant to high concentrations of antibiotics. Yet the propensity of Candida spp. to form aggregates is unknown.

OBJECTIVE

To assess the ability of numerous Candida spp. to form synovial fluid aggregates and the clinical ramifications of the aggregates.

METHODS

Nine different Candidal prosthetic joint infection clinical isolates were evaluated for their ability to form aggregates at static and dynamic conditions and their resistance to high concentrations of amphotericin. Furthermore, the ability of tissue plasminogen activator (TPA) to disrupt the aggregates and enhance amphotericin activity was assessed.

RESULTS

The results show that all species of Candida spp. evaluated formed aggregates in synovial fluid under dynamic conditions that were resistant to amphotericin. Yet no aggregates formed in tryptic soy broth under any conditions or in synovial fluid under static conditions. As well, when TPA was combined with amphotericin there was a statistically significant decrease (p < .005) in the amount of colony forming units per mL for all Candidal species evaluated. Interestingly, for Candida krusei there was no colony forming units observed after exposure to TPA and amphotericin.

CONCLUSION

Our findings suggest that Candidal species form synovial fluid aggregates that are resistant to high dose amphotericin similar to those that occur with bacteria. However, the varying ability of the different Candida spp. to form hyphae and pseudohyphae compared to yeast cells may have direct impacts on the hardiness of the aggregates and thereby have clinical ramifications with respect to treatment durations.

In vitro Evaluation of Fungal Susceptibility and Inhibition of Virulence by Diosgenin

Fungal infections are a public health problem that mainly affects immunosuppressed people, Candida spp. have been responsible for most sources of contamination and invasive fungal infections described around the world. The need arises to find new therapeutic approaches to combat growing infections. Plants and natural products have been considered a valuable source for discovering new molecules with active ingredients. Diosgenin is a sapogenin found in the families of Leguminosae and Dioscoreaceae, it is obtained mainly from the dioscin saponin through the hydrolysis method, it is a phytochemical that has been highlighted in the treatment of various diseases, as well as in combating microbial resistance. The present study aimed to evaluate the susceptibility of fungal strains to diosgenin, as well as verify the association with the reference drug and evaluate the inhibition of the virulence factor through morphological changes in the yeast state to the filamentous form of hyphae and pseudohyphae in strains of Candida albicans, Candida tropicalis and Candida krusei using the broth microdilution method and microculture technique. Antifungal assays revealed that diosgenin was not able to inhibit the growth of the tested strains. However, it was able to inhibit the fungal dimorphism of the strains evaluated, however further studies are recommended to verify its effectiveness against other virulence factors.