Antifungal Targets Research Articles

Novel mitochondrial-targeted alkyl chains act as fungal specific inhibitors of C. neoformans

Cryptococcus neoformans is the causal agent of cryptococcal meningitis in immunocompromised patients and increasing instances of anti-fungal resistance have led to investigations into new alternative antifungal targets. For example, C. neoformans possesses an Alternative Oxidase enzyme (Aox) that has been implicated in stress resistance and virulence that may represent a viable antifungal target. Here we test the efficacy of mitochondrially-targeted Colletochlorin B, which has been shown to inhibit the Aox of Candida albicans in vitro. Two derivatives of Colletochlorin B, which we modified to improve delivery to mitochondria, were identified as putative fungal-specific inhibitors. ALTOX094 and ALTOX102 were able to inhibit Aox and cytochrome bc1in vitro and demonstrated strong inhibitory effects against C. neoformans growth and viability. Further analysis suggested that the antifungal properties of ALTOX094 and ALTOX102 were attributable to different modes of action and forms of cell death, governed largely by the alkyl chain length used to tether Colletochlorin B to the mitochondria targeting triphenylphosphine (TPP) moiety. Our findings add to the growing evidence that functionalized mitochondria targeted alkyl chains may developed further as an effective class of antifungal and are effective against C. neoformans.

Prediction and Validation of New Targets of NNPCN in Inhibiting Rhizoctonia Solani Based on Molecular Docking, Dynamics, and Biotechnology.

The antifungal targets of the new fungicide N-(naphthalen-1-yl)-phenazine-1-carboxamide (NNPCN) are still incomplete, limiting its application. To identify potential new targets of NNPCN and facilitate target hunting, a suite of techniques was employed to conduct experiments on Rhizoctonia solani. Nine potential targets were identified, exhibiting strong binding affinity to NNPCN, as indicated by binding free energies below -100.000 kJ/mol. Notably, pectin lyase, glycosyl hydrolase, fumarate transporter, and cytochrome monooxygenase showed exceptionally strong binding. The mRNA expression analysis revealed significant downregulation in certain target genes: E3 ubiquitin ligase (AG1IA_02506), aldehyde dehydrogenase (AG1IA_03762), fumarate transporter (AG1IA_03944), and pectin lyase (AG1IA_03046) decreased by 42%, 66%, 83%, and 69%, respectively, while other key genes were upregulated. Pectin lyase protein was obtained through prokaryotic expression at 0.4 mg/mL concentration. A novel thiobarbituric acid test system verified pectin lyase as a potential NNPCN target, with the enzyme activity multiple being only 0.169 after NNPCN treatment. These findings enhance our understanding of NNPCN's mode of action and could guide its improved application.

The sulfur-related metabolic status of Aspergillus fumigatus during infection reveals cytosolic serine hydroxymethyltransferase as a promising antifungal target

ABSTRACT Sulfur metabolism is an essential aspect of fungal physiology and pathogenicity. Fungal sulfur metabolism comprises anabolic and catabolic routes that are not well conserved in mammals, therefore is considered a promising source of prospective novel antifungal targets. To gain insight into Aspergillus fumigatus sulfur-related metabolism during infection, we used a NanoString custom nCounter-TagSet and compared the expression of 68 key metabolic genes in different murine models of invasive pulmonary aspergillosis, at 3 time-points, and under a variety of in vitro conditions. We identified a set of 15 genes that were consistently expressed at higher levels in vivo than in vitro, suggesting that they may be particularly relevant for intrapulmonary growth and thus constitute promising drug targets. Indeed, the role of 5 of the 15 genes has previously been empirically validated, supporting the likelihood that the remaining candidates are relevant. In addition, the analysis of gene expression dynamics at early (16 h), mid (24 h), and late (72 h) time-points uncovered potential disease initiation and progression factors. We further characterized one of the identified genes, encoding the cytosolic serine hydroxymethyltransferase ShmB, and demonstrated that it is an essential gene of A. fumigatus, also required for virulence in a murine model of established pulmonary infection. We further showed that the structure of the ligand-binding pocket of the fungal enzyme differs significantly from its human counterpart, suggesting that specific inhibitors can be designed. Therefore, in vivo transcriptomics is a powerful tool for identifying genes crucial for fungal pathogenicity that may encode promising antifungal target candidates.

Humanized Candida and NanoBiT Assays Expedite Discovery of Bdf1 Bromodomain Inhibitors With Antifungal Potential.

The fungal Bromodomain and Extra-Terminal (BET) protein Bdf1 is a potential antifungal target against invasive fungal infections. However, the need to selectively inhibit both Bdf1 bromodomains (BDs) over human orthologs and the lack of molecular tools to assess on-target antifungal efficacy hamper efforts to develop Bdf1 BD inhibitors as antifungal therapeutics. This study reports a phenyltriazine compound that inhibits both Bdf1 BDs from the human fungal pathogen Candida glabrata with selectivity over the orthologous BDs from the human BET protein Brd4. On-target antifungal activity is established by devising two yeast-based inhibition assays: a growth assay using humanized Candida strains in which the Bdf1 BDs are replaced by their Brd4 counterparts, and a NanoBiT assay that evaluates the BD-mediated association of Bdf1 with chromatin. These assays additionally enable the discovery that BET inhibitor I-BET726 targets both Bdf1 BDs, inhibits the growth of a broad spectrum of Candida species, including antifungal-resistant clinical isolates, and displays efficacy in an invertebrate animal model of infection. These collective findings highlight the promising potential of Bdf1 BD inhibitors as an innovative class of antifungal therapeutics and the pivotal role of yeast-based assay development toward achieving this end.

Structure-guided optimization of small molecules targeting the yeast casein kinase, Yck2, as a therapeutic strategy to combat Candida albicans.

Candida albicans is the most common cause of life-threatening fungal infection in the developed world but remains a therapeutic challenge. Protein kinases have been rewarding drug targets across diverse indications but remain untapped for antifungal development. Previously, screening kinase inhibitors against C. albicans revealed a 2,3-aryl-pyrazolopyridine, GW461484A (GW), which targets casein kinase 1 (CK1) family member Yck2. Here, we report optimization of GW via two complementary approaches, synthesis of bioisosteres possessing an imidazo[1,2-a]pyridine core, and R-group substitution of GW's pyrazolo[1,5-a]pyridine core. Characterization of compounds synthesized revealed two 6-cyano derivatives with improved pharmacological properties that retained whole-cell bioactivity and selectivity for fungal Yck2 compared to human CK1α. Efficacy studies in mice indicated both analogs possess single-agent activity against C. albicans resistant to first-line echinocandin antifungals and potentiate non-curative echinocandin treatment. Results validate Yck2 as an antifungal target and encourage further development of inhibitors acting by this previously unexploited mode of action.

Butyrolactol A is a phospholipid flippase inhibitor that potentiates the bioactivity of caspofungin against resistant fungi.

Fungal infections cause millions of deaths annually and are challenging to treat due to limited antifungal options and increasing drug resistance. Cryptococci are intrinsically resistant to the latest generation of antifungals, echinocandins, while Candida auris , a notorious global threat, is also increasingly resistant. We performed a natural product extract screen for rescue of the activity of the echinocandin caspofungin against Cryptococcus neoformans H99, identifying butyrolactol A, which restores echinocandin efficacy against resistant fungal pathogens, including C. auris . Mode of action studies revealed that butyrolactol A inhibits the phospholipid flippase Apt1-Cdc50, blocking phospholipid transport. Cryoelectron-microscopy analysis of the Apt1●butyrolactol A complex revealed that the flippase is locked in a dead-end state. Apt1 inhibition disrupts membrane asymmetry, vesicular trafficking, and cytoskeletal organization, thereby enhancing echinocandin uptake and potency. This study identifies flippases as promising antifungal targets and demonstrates the potential of revisiting natural products to expand the antifungal arsenal and combat resistance.

Synthesis and antifungal evaluation of new azole derivatives containing 1,2,3-triazole.

Invasive fungal infections caused by C. albicans are becoming increasingly serious and there is an urgent need for exploring new antifungal drugs. In the present work, a series of new azole derivatives containing a 1,2,3-triazole moiety have been prepared, and in vitro antifungal activity have been evaluated. The results revealed that most compounds showed excellent antifungal activity against C. albicans SC5314 and drug-resistant SC5314-FR. In particular, compounds 4h, 4j, 4l, 4s and 4w exhibited better antifungal activity than FLC. The preliminary mechanism study indicated that 4s could damage the integrity of the cell structure, increase the permeability of the cell membrane, and cause the leakage of cell contents of C. albicans. The molecular docking study indicated that 4s showed an obvious binding site with the target CYP51 (PDB ID: 5TL8). Therefore, 4s could be considered as a new antifungal agent targeting CYP51 for further study.

Insights into a tetra dentate schiff base complex: Structural, electronic and antifungal target interactions

Insights into a tetra dentate schiff base complex: Structural, electronic and antifungal target interactions

The Significance of Mono- and Dual-Effective Agents in the Development of New Antifungal Strategies.

Invasive fungal infections (IFIs) pose significant challenges in clinical settings, particularly due to their high morbidity and mortality rates. The rising incidence of these infections, coupled with increasing antifungal resistance, underscores the urgent need for novel therapeutic strategies. Current antifungal drugs target the fungal cell membrane, cell wall, or intracellular components, but resistance mechanisms such as altered drug-target interactions, enhanced efflux, and adaptive cellular responses have diminished their efficacy. Recent research has highlighted the potential of dual inhibitors that simultaneously target multiple pathways or enzymes involved in fungal growth and survival. Combining pharmacophores, such as lanosterol 14α-demethylase (CYP51), heat shock protein 90 (HSP90), histone deacetylase (HDAC), and squalene epoxidase (SE) inhibitors, has led to the development of compounds with enhanced antifungal activity and reduced resistance. This dual-target approach, along with novel chemical scaffolds, not only represents a promising strategy for combating antifungal resistance but is also being utilized in the development of anticancer agents. This review explores the development of new antifungal agents that employ mono-, dual-, or multi-target strategies to combat IFIs. We discuss emerging antifungal targets, resistance mechanisms, and innovative therapeutic approaches that offer hope in managing these challenging infections.

Sdd3 regulates the biofilm formation of Candida albicans via the Rho1-PKC-MAPK pathway.

Candida albicans, the most frequently isolated fungal pathogen in humans, forms biofilms that enhance resistance to antifungal drugs and host immunity, leading to frequent treatment failure. Understanding the molecular mechanisms governing biofilm formation is crucial for developing anti-biofilm therapies. In this study, we conducted a genetic screen to identify novel genes that regulate biofilm formation in C. albicans. One identified gene is ORF19.6693, a homolog of the Saccharomyces cerevisiae SDD3 gene. The sdd3∆/∆ mutant exhibited severe defects in biofilm formation and significantly reduced chitin content in the cell wall. Overexpression of the constitutively active version of the Rho1 GTPase Rho1G18V, an upstream activator of the protein kinase C (PKC)-mitogen-activated protein kinase (MAPK) cell-wall integrity pathway, rescued these defects. Affinity purification, mass spectrometry, and co-immunoprecipitation revealed Sdd3's physical interaction with Bem2, the GTPase-activating protein of Rho1. Deletion of SDD3 significantly reduced the amount of the active GTP-bound form of Rho1, thereby diminishing PKC-MAPK signaling and downregulating chitin synthase genes CHS2 and CHS8. Taken together, our studies identify a new biofilm regulator, Sdd3, in C. albicans that modulates Rho1 activity through its inhibitory interaction with Bem2, thereby regulating the PKC-MAPK pathway to control chitin biosynthesis, which is critical for biofilm formation. As an upstream component of the pathway and lacking a homolog in mammals, Sdd3 has the potential to serve as an antifungal target for biofilm infections.IMPORTANCEThe human fungal pathogen Candida albicans is categorized as a critical priority pathogen on the World Health Organization's Fungal Priority Pathogens List. A key virulence attribute of this pathogen is its ability to form biofilms on the surfaces of indwelling medical devices. Fungal cells in biofilms are highly resistant to antifungal drugs and host immunity, leading to treatment failure. This study conducted a genetic screen to discover novel genes that regulate biofilm formation. We found that deletion of the SDD3 gene caused severe biofilm defects. Sdd3 negatively regulates the Rho1 GTPase, an upstream activator of the protein kinase C-mitogen-activated protein kinase pathway, through direct interaction with Bem2, the GTPase-activating protein of Rho1, resulting in a significant decrease in chitin content in the fungal cell wall. This chitin synthesis defect leads to biofilm formation failure. Given its essential role in biofilm formation, Sdd3 could serve as an antifungal target for biofilm infections.

Potential Antimicrobial and Cytotoxic Activity of Caralluma indica Seed Extract.

Background: Plant-derived phytochemicals are crucial in fighting bacterial infections and in cancer therapy. Objective: This study investigates the phytochemical composition of the ethanolic extract obtained from Caralluma indica (C. indica) seeds and assesses its antimicrobial, anticancer, and antioxidant activities. Results: GC-MS analysis found 30 phytochemicals in C. indica seeds, including 5 bioactive compounds that have been shown to have antioxidant, antimicrobial, and cytotoxicity properties, through in silico evaluation. Phytochemical screening of C. indica identified and measured the phenolic compounds, providing insight into its bioactive potential and therapeutic properties. C. indica exhibited robust antioxidant capacity (DPPH, ABTS, nitric oxide, and H2O2 radical scavenging) alongside potent antimicrobial activity against oral pathogen and cytotoxicity activity on a human oral squamous carcinoma cell line (OECM-1) (EC50 of 169.35 µg/mL) and yeast cell Saccharomyces cerevisiae (215.82 µg/mL), with a selective index of 1.27. The subminimum % MBC/MFC of C. indica significantly reduced biofilm formation against oral pathogens (p < 0.05). Molecular docking studies showed a strong correlation (r = 0.862) between antifungal and anticancer targets, suggesting that the antimicrobial agents in C. indica contribute to cancer prevention mechanisms. Conclusions: These findings propose C. indica seeds as promising candidates for combating oral pathogens, inhibiting biofilm formation, and reducing the risk of oral cancer progression.

Antifungal stewardship in Australian hospitals: defining the scope and future targets

AbstractBackgroundAntimicrobial stewardship (AMS) guidelines now recommend antifungal stewardship (AFS) interventions to improve the management of invasive fungal diseases (IFDs). AFS programmes have not been reported in Australia.AimsTo determine the monitoring of antifungal use, AFS strategies and targets, and barriers to AFS implementation in Australian hospitals.MethodsAn electronic quantitative cross‐sectional survey was developed and distributed to public and private hospitals in Australia in February 2018. Descriptive statistics were used to summarise the findings.ResultsEighty‐three Australian hospitals completed the survey with an overall response rate of 58% (83/143). Most hospitals monitored antifungal use (62/83, 75%). Frequently used AFS metrics included costs (48/60, 80%) and yearly point prevalence surveys (45/60, 75%). Core AFS strategies were commonly in place, including preauthorisation requirements (71/80, 89%) and expert antifungal post‐prescription review and feedback (PPRF) (63/80, 79%). Both these strategies were more strictly applied to high‐cost, intravenous agents. Formal education (44/79, 56%) and hospital‐endorsed guidelines (35/79, 44%) were modestly used. Fungal diagnostics and antifungal therapeutic drug monitoring (TDM) were utilised, largely off site. IFD surveillance was infrequently performed (9/77, 12%). Barriers to AFS identified included lack of staff time, prioritisation of AFS, and access to rapid diagnostics and TDM.ConclusionsAFS strategies utilised in Australian hospitals have focused on high‐cost, intravenous agents. Although expert oversight of antifungals is evident, many sites omit potentially important targets for AFS, including fluconazole and oral posaconazole. Identifying these gaps and barriers to AFS will guide the development of an AFS model for hospitals.

The core septin gene CgSEP5 is associated with formation of infection structures and pathogenicity in Colletotrichum gloeosporioides.

Colletotrichum gloeosporioides is a model plant pathogenic fungus, and the appressoria are the main infection structures integral to the pathogenic process. Septin proteins play fundamental roles in facilitating shape alteration and organizing the F-actin cytoskeleton, thereby aiding the invasive growth of various fungi. Herein, we examined the roles of four septin-coding genes (CgSEP3, CgSEP4, CgSEP5, and CgSEP6) in C. gloeosporioides. Our findings reveal the diverse functions of septins in C. gloeosporioides, which encompass the regulation of vegetative growth, conidiation, cell wall integrity, and stress responses. Critically, septins are involved in the formation, invasion, and expansion of infection structures and they directly influence virulence on unwounded hosts. Interestingly, the deletion of CgSEP4 resulted in the formation of hooked and bent germ tubes and caused a significant decrease in appressorium turgor pressure, which has not been reported in other fungi. Our findings demonstrated that CgSEP3 and CgSEP6 were regulated by ROS signal transduction during the formation of infection structure. Moreover, the knockout of the key component, CgSEP5, significantly decreased growth rate compared to the wild type, completely blocking the penetration of infection structures and subsequently abolishing virulence on poplar leaves. By subcellular localization of GFP fusions, it was proved that CgSEP5 may regulate the formation of appressorial pegs in C. gloeosporioides through forming a ring-like structure inside the appressorium. Collectively, our research underscores the pivotal role of septins in fungal pathogenicity, by orchestrating the formation and development of infection structures. We speculate that CgSEP5 function as a promising anti-fungal target, and believe these findings provide a substantial reference for future investigations into the mechanisms underpinning the invasion of fungi appressoria on woody plants.

Discovery of new fungal jumonji H3K27 demethylase inhibitors for the treatment of Cryptococcus neoformans and Candida auris infections

Invasive fungal infections have become a serious public health problem. To tackle the challenges of limited efficacy in antifungal therapy and severe drug resistance, antifungal drugs with new mechanisms of action are urgently needed. Our previous study identified JIB-04 to be an inhibitor of fungal histone demethylase (HDM). To promote target validation and inhibitor design, herein a series of new JIB-04 derivatives were designed and synthesized. After the establishment of structure-activity relationship, compound A4 was identified to possess potent antifungal activity against Cryptococcus neoformans and Candida auris. Compared to lead compound JIB-04, compound A4 was a more potent HDM inhibitor and exhibited better water solubility, virulence factors inhibitory activity and in vivo antifungal potency. Collectively, this study further confirmed that fungal HDMs were potential antifungal targets and compound A4 was a promising antifungal lead compound.

An Insight into the Repurposing of Phytoconstituents obtained from Delhi's Aravalli Biodiversity Park as Antifungal Agents.

The global prevalence of fungal infections is alarming in both the pre- and post- COVID period. Due to a limited number of antifungal drugs, there are hurdles in treatment strategies for fungal infections due to toxic potential, drug interactions, and the development of fungal resistance. All the antifungal targets (existing and newer) and pipeline molecules showing promise against these targets are reviewed. The objective was to predict or repurpose phyto-based antifungal compounds based on a dual target inhibition approach (Sterol-14-α- demethylase and HSP-90) using a case study. In pursuit of repurposing the phytochemicals as antifungal agents, a team of researchers visited Aravalli Biodiversity Park (ABP), Delhi, India, to collect information on available medicinal plants. From 45 plants, a total of 1149 ligands were collected, and virtual screening was performed using Schrodinger Suite 2016 software to get 83 hits against both the target proteins: Sterol-14-α-demethylase and HSP-90. After analysis of docking results, ligands were selected based on their interaction against both the target proteins and comparison with respective standard ligands (fluconazole and ganetespib). We have selected Isocarthamidin, Quercetin and Boeravinone B based on their docking score and binding interaction against the HSP-90 (Docking Score -9.65, -9.22 and -9.21, respectively) and 14-α-demethylase (Docking Score -9.19, -10.76 and -9.74 respectively). The docking protocol was validated and MM/GBSA studies depicted better stability of selected three ligands (Isocarthamidin, Quercetin, Boeravinone B) complex as compared to standard complex. Further, MD simulation studies were performed using the Desmond (67) software package version 2018-4. All the findings are presented as a case study for the prediction of dual targets for the repurposing of certain phytochemicals as antifungal agents.

Evaluation of Emulsification Techniques to Optimize the Properties of Chalcone Nanoemulsions for Antifungal Applications.

Background/Objectives: Nanoemulsions (NEs) possess properties that enhance the solubility, bioavailability and therapeutic efficacy of drugs. Chalcones are compounds known for their antifungal properties. In this study, we evaluated different emulsification techniques to create alginate nanoemulsions containing chalcone (1E,4E)-1,5-bis (4-methoxyphenyl) penta-1,4-dien-3-one (DB4OCH3). Our goal was to develop an antifungal formulation targeting Candida albicans strains. Methods: Ultrasound and ultrasound combined with high-speed homogenization techniques were used to prepare alginate-stabilized nanoemulsions. Particle size, zeta potential and encapsulation efficiency were evaluated. Additionally, in vitro release studies were conducted. Results: The combined emulsification technique produced stable nanoparticles with high encapsulation efficiency and antifungal activity, with a minimum inhibitory concentration of 8.75 μg/mL for the nanoemulsions compared to 312 µg/mL for free DB4OCH3. NEs' effectiveness can be attributed to their ability to form nanodroplets efficiently, facilitating the solubilization of the chalcone in the oily phase. The particle size varied between 195.70 ± 2.69 and 243.40 ± 4.49 nm, with an increase in chalcone concentration leading to larger particle sizes. The zeta potential showed values from -91.77 ± 5.58 to -76.90 ± 4.44 mV. The UHS-7 sample exhibited an encapsulation efficiency of 92.10% ± 0.77, with a controlled in vitro release of 83% after 34 h. Molecular docking simulations showed that the aromatic nature of DB4OCH3 resulted in the formation of apolar interactions with aromatic residues located in the active site of the TMK, as observed in their respective co-crystallized inhibitors, within an affinity energy range that enables optimum specificity of the ligand for these two pathways. Pharmacokinetic analyses indicated high passive cell permeability and low hepatic clearance, and phase I metabolism reduces its oral bioavailability and metabolic stability, suggesting a promising active ingredient as an oral drug with control of the daily oral dose administered. Conclusions: The combined nanoemulsification technique led to the formation of finely dispersed nanodroplets that favored the solubilization of the chalcone in the oil phase, which led to a better performance in the antifungal properties. DB4OCH3 shows promise as an oral drug with controlled dosing.

New acetophenone scaffolds: Synthesis, antifungal activities, biocompatibility, molecular docking, ADMET analysis and dynamic simulations

In this work, the chemical reactivity of 2-cyano-N′-(1-phenylethylidene)acetohydrazide (3) towards different aldehydes is utilized to synthesize binary and fused heterocyclic compounds, including arylidenes 6, 7, 12, 13, 14, 18a-c, 19a,b, 20, chromone 23, and chromene derivatives 24, 26a-c, 29, and 30. The capability of newly synthesized compounds to inhibit fungal growth of Aspergillus niger ATCC 16404, A. flavus ATCC 9643, Penicillium chrysogenum ATCC 10106, and Rhizopus oryazae ATCC 96382 are assessed. It is observed that compound 29 had strong antifungal activity against all fungi with MFIC values varying from 250 to 1000 µg/ml, while compound 18a demonstrated potent antifungal effect against A. niger and A. flavus. In addition, it is found that compound 29 was cytotoxic to Vero cells at doses of 1000–500 µg/ml; however, no discernible variation was observed between the concentrations of 250–31.25 µg/ml. Moreover, the interactions between the promising compounds 18a, 19b, and 29 and antifungal target proteins are assessed using molecular docking. The results of the docking simulations demonstrated that these compounds demonstrated optimal binding energies and effectively engaged with the active sites of FDC1 protein in A. niger, UDP-N-acetylglucosamine in A. fumigatus, Adenosine 5′-phosphosulfate kinase in P. chrysogenum, and protease in Rhizopus oryazae. These interactions involved various types of molecular interactions, indicating that these compounds have the ability to impede enzymes and exhibit strong antimicrobial effects. Furthermore, the in-silico ADMET profiles of compounds 18a, 19b, and 29 reveal that they adhere to the Lipinski rules, suggesting favorable physicochemical properties. Also, MD simulations revealed stable complexes of 29 with anti-fungal receptors including fdc1, UDP-N-acetylglucosamine, APS kinase, and protease with RMSD (0.1–0.8, 0.19–0.25, 0.20–0.30, and 0.20–0.35 nm), RMSF (0.1–0.8 nm), SASA (140–155, 130–140, 135–145, and 120–130 nm2), and Rg (1.90–2.00, 1.80–1.90, 2.40–2.50, and 2.10–2.20 nm) respectively. Our results provide potential and promising compounds for fungal infection diseases.

Fungal L-Methionine Biosynthesis Pathway Enzymes and Their Applications in Various Scientific and Commercial Fields.

L-methionine (L-Met) is one of the nine proteinogenic amino acids essential for humans since, in human cells, there are no complete pathways for its biosynthesis from simple precursors. L-Met plays a crucial role in cellular function as it is required for proper protein synthesis, acting as an initiator. Additionally, this amino acid participates in various metabolic processes and serves as a precursor for the synthesis of S-adenosylmethionine (AdoMet), which is involved in the methylation of DNA molecules and phospholipids, as well as in maintaining genome stability. Due to its importance, fungal L-methionine biosynthesis pathway enzymes are being intensively studied. This review presents the current state of the art in terms of their cellular function, usefulness as molecular markers, antifungal targets, or industrial approaches.

The riboflavin biosynthetic pathway as a novel target for antifungal drugs against Candida species.

Candida species are a common cause of invasive fungal infections. Candida albicans, in particular, poses a significant threat to immunocompromised individuals. This opportunistic pathogen typically lives as a commensal on mucosal surfaces of healthy individuals but it can also cause invasive infections associated with high morbidity and mortality. Currently, there are only three major classes of antifungal drugs available to treat these infections. In addition, the efficacy of these antifungal agents is restricted by host toxicity, suboptimal pharmacokinetics, a narrow spectrum of activity, intrinsic resistance of fungal species, such as Candida glabrata, to certain drugs, and the acquisition of resistance over time. Therefore, it is crucial to identify new antifungal drug targets with novel modes of action to add to the limited armamentarium.

Unveiling the roles of CaSDH8 in Candida albicans: Implications for virulence and azole resistance

ABSTRACT Candida albicans is the most common pathogen in systemic fungal diseases, exhibits a complex pathogenic mechanism, and is increasingly becoming drug tolerant. Therefore, it is particularly important to study the genes associated with virulence and resistance of C. albicans. Here, we identified a gene (orf19.1588) that encodes a conserved mitochondrial protein known as CaSDH8, upon deletion of CaSdh8, the deleted strain (Casdh8Δ/Δ) experienced impaired growth, hyphal development, and virulence. Casdh8Δ/Δ displayed a reduced capacity to utilize alternative carbon sources, along with detrimental alterations in reactive oxygen species (ROS), mitochondrial membrane potential (MMP) depolarization, and adenosine triphosphate (ATP) levels. Interestingly, Casdh8Δ/Δ demonstrated resistance to azole drugs, and under the influence of fluconazole, the cell membrane permeability and mitochondrial function of Casdh8Δ/Δ were less compromised than those of the wild type, indicating a reduction in the detrimental effects of fluconazole on Casdh8Δ/Δ. These findings highlight the significance of CaSDH8 as a crucial gene for the maintenance of cellular homoeostasis. Our study is the first to document the effects of the CaSDH8 gene on the virulence and azole resistance of C. albicans at both the molecular and animal levels, providing new clues and directions for the antifungal infection and the discovery of antifungal drug targets.