The Fungal Cell Wall: Candida, Cryptococcus, and Aspergillus Species

Compartmentalized co-immobilization of cellulase and cellobiose phosphorylase within zeolitic imidazolate framework efficiently synthesizes 1-p-Glc: Glycosylation of 18FDG

Enzymatic glycosylation is an efficient and biocompatible approach to enhance natural product bioavailability. Cellobiose phosphorylase, a novel glycosyltransferase, utilizes 1-phospho-glucose (1-p-Glc) as a glycosyl donor for regioselective glycosylation of various natural substrates. However, the high cost of 1-p-Glc limits the economic feasibility of the process. Thus, a dual-enzyme cascade system involving cellulase AcCel9A and cellobiose phosphorylase CbCBP using a co-immobilization strategy was developed to overcome this challenge. The system utilizes low-cost carboxymethyl cellulose (CMC) for continuous 1-p-Glc production, which was then used in the fluorodeoxy glucose (FDG) glycosylation to generate fluorodeoxy cellobiose (FDC), which potentially traces fungal infections. The compartmentalized co-immobilization of the two enzymes within the internal and external regions of a porous zeolitic imidazolate framework-8 (ZIF-8) carrier enhanced the overall stability of the dual-enzyme system. The immobilized enzymes retained approximately 63.3 % activity after seven reuse cycles and 74 % catalytic efficiency after 12 days of storage at room temperature. Therefore, the developed co-immobilized multi-enzyme system holds significant potential for industrial biocatalysis applications.

Enhanced biocidal efficacy of alcohol based disinfectants with salt additives

Surfaces contaminated with pathogens pose a significant risk of disease transmission and infection. Alcohol-based disinfectants are widely utilized to decontaminate high-touch areas across various settings. However, their limited antimicrobial activity and the emergence of alcohol-tolerant strains necessitate the development of highly efficient disinfectant formulations. In this work we test the broad-spectrum antimicrobial activities of the salt-incorporated alcohol solution disinfectant against enveloped and non-enveloped viruses, spore-forming and non-spore-forming bacteria, and mold and yeast fungi. Specifically, the disinfection capability of the isopropanol (IPA) and ethanol (EtOH) solutions containing NaCl salts was evaluated by measuring (1) antibacterial activity against Gram-positive bacteria (methicillin-resistant Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), and an alcohol-tolerant strain of E. coli; (2) sporicidal activity against Clostridioides difficile; (3) the antiviral activity against enveloped A/PR8/34 H1N1 influenza virus and non-enveloped adenovirus VR-5; and (4) the antifungal efficacy against Aspergillus niger and Cryptococcus neoformans from the time-dependent viability assays. Additionally, the biocidal activity of the disinfectant formulation was tested by spraying it on the biocontaminated surfaces, including plastics, stainless steel, and glass. Overall, the inclusion of salt in alcohol solutions significantly enhanced their disinfection activities, positioning these solutions as promising candidates for long-term disinfection and maintenance of hygienic environments. This method, which employs mild salt instead of toxic materials, offers a simpler, more cost-effective, and safer alternative to conventional alcohol-based disinfectants. This research is expected to significantly impact on disease prevention and contribute greatly to public health and safety.

Candidiasis: Insights into Virulence Factors, Complement Evasion and Antifungal Drug Resistance

Invasive fungal infections constitute a substantial global health burden, with invasive candidiasis representing approximately 70% of reported cases worldwide. The emergence of antifungal resistance among Candida species has further exacerbated this challenge to healthcare systems. Recent epidemiological studies have documented a concerning shift towards non-albicans Candida species, exhibiting reduced antifungal susceptibility, in invasive candidiasis cases. The complement system serves as a crucial first-line defence mechanism against Candida infections. These fungal pathogens can activate the complement cascade through three conventional pathways-classical, lectin, and alternative-in addition to activation through the coagulation system. While these pathways are initiated by distinct molecular triggers, they converge at C3 convertase formation, ultimately generating biologically active products and the membrane attack complex. Candida species have evolved sophisticated mechanisms to evade complement-mediated host defence, including the masking of cell wall components, proteolytic cleavage and inhibition of complement proteins, recruitment of complement regulators, and acquisition of host proteins. This review examines the intricate interplay between Candida species and the host complement system, with emphasis on complement evasion strategies. Furthermore, we highlight the importance of exploring the crosstalk between antifungal resistance and immune evasion strategies employed by Candida species. Understanding these interactions may facilitate the development of novel therapeutic approaches and strategies to overcome treatment failures in Candida species infections.

A microbial natural product fractionation library screen with HRMS/MS dereplication identifies new lipopeptaibiotics against Candida auris

The rise of drug-resistant fungal pathogens, including Candida auris, highlights the urgent need for novel antifungal therapies. We developed a cost-effective platform combining microbial extract prefractionation with rapid MS/MS-bioinformatics-based dereplication to efficiently prioritize new antifungal scaffolds. Screening C. auris and C. albicans revealed novel lipopeptaibiotics, coniotins, from Coniochaeta hoffmannii WAC11161, which were undetectable in crude extracts. Coniotins exhibited potent activity against critical fungal pathogens on the WHO Fungal Priority Pathogens List, including C. albicans, C. neoformans, multidrug-resistant C. auris, and Aspergillus fumigatus, with high selectivity and low resistance potential. Coniotin A targets β-glucan, compromising fungal cell wall integrity, remodelling, and sensitizing C. auris to caspofungin. Identification of a PKS-NRPS biosynthetic gene cluster further enables the discovery of related clusters encoding potential novel lipopeptaibiotics. This study demonstrates the power of natural product prefractionation in uncovering bioactive scaffolds and introduces coniotins as promising candidates for combating multidrug-resistant fungal pathogens.

Reviewing the audacity of elixirs of inflammatory bowel disease from mushroom β-glucans: The solved and unresolved

BACKGROUND

Mushrooms are known as the elixirs of life, they are packed with various bioactive compounds that make them not only tasty but also healthy. Thus, they not just fall within the category of nutritional foods, but also functional foods. When medicinal bioactive components are sought after from every other available resource, these natural reservoirs are easily accessible therapeutic sources. Of the various bioactive that mushrooms have to offer, β-glucans are the most enriching.

METHODS

β-glucans are available in other sources as well, but their relative abundance is higher in mushrooms. Amidst the cascade of biological benefits from β-glucans, anti-inflammatory benefits are highly promising. In this present review, the anti-inflammatory properties of mushroom β-glucans have been discussed and its specific contributions against inflammatory bowel disease have been reviewed.

DISCUSSION

What is known regarding the modulus operandi of β-glucans against inflammatory bowel disease has been summarized and the gaps and lapses in the current understanding highlighted. This is the first state-of-the-art review that presents a comprehensive executive summary and discussion in this subject area.

Current Updates on Molecular Diagnostic Assays Used for Detection of Candida auris: A Systematic Review

Background/Objectives: Candida auris is an emerging multidrug-resistant pathogen with the potential to cause invasive fungal infections and healthcare-associated outbreaks. Currently, there is no systematic review explicitly focusing on the up-to-date molecular diagnostics of this pathogen to cover the entire process, including sample pre-extraction procedures, nucleic acid extraction, and DNA-based detection. Sample pre-treatment and extraction are the prerequisites before molecular testing and have implications on the downstream detection but have not been reviewed elsewhere. This review aims to summarize a comprehensive update in the past 5 years. Methods: A systematic review was conducted to search for articles published in the period between 1 January 2020 and 20 November 2024 from various databases, including PubMed, Google Scholar, and Web of Science. The findings were produced through narrative synthesis, with quantitative analysis conducted where applicable. Results: Starting from 1115 records, 28 studies that met the inclusion criteria were included in the analysis. This review summarized the key updates on three categories, including (i) sample pre-extraction procedures and nucleic acid extraction, including magnetic, bead-beating, mechanical, chemical, thermal, and column-based protocols; (ii) commercial molecular assays; and (iii) laboratory-developed tests (LDTs). For real-time PCR, commercial molecular assays and LDTs showed sensitivity (ranging from 94.9% to 100% and 44% to 100%, respectively) and specificity (ranging from 98.2% to 100% and 92% to 100%, respectively). Conclusions: Here, we describe a useful summary to enlighten readers from clinical microbiology laboratories on the nucleic acid extraction protocols and performance of various molecular diagnostic assays used for the detection of C. auris.

Miconazole-splitomicin combined β-glucan hydrogel for effective prevention of Candida albicans periprosthetic joint infection

As one of the most common and serious infections caused by Candida albicans (C. albicans), periprosthetic joint infection (PJI) increasingly concerns surgeons and scientists. Generally, biofilms shield C. albicans from antifungal agents and immune clearance and induce drug-resistant strains. Developing novel strategies for PJI to get rid of current drug-resistant problems is highly needed. In our study, splitomicin (SP) can inhibit the mycelium formation of C. albicans and enhance the drug sensitivity of C. albicans to miconazole nitrate (MCZ). The combination of SP and MCZ significantly inhibited the viability, proliferation and adhesion of C. albicans, reduced the yeast to hyphae transition and biofilm formation. When SP and MCZ were coloaded in the β-glucan hydrogel, a viscoelastic solid with porous 3D network, sustained release and erosion properties was obtained. In the in vivo PJI mice model, SP-MCZ-β-glucan hydrogel effectively reduced the colonization and aggregation of C. albicans around the implant, reduced the pathological changes caused by C. albicans in the femur tissue. Therefore, SP-MCZ-β-glucan hydrogel holds a great promise for the management of C. albicans infection around joint prosthesis.

The nuclear pore protein Nup2 is essential for growth and development, stress response, pathogenicity and deoxynivalenol biosynthesis in Fusarium graminearum

BACKGROUND

Wheat is an important grain crop that has been under serious threat from Fusarium graminearum. Nup2, a member of the nuclear pore complex, plays an important role in regulating eukaryotic nuclear protein transport and participates in gene regulation. Dissecting the function of nuclear pore proteins in pathogenic fungi may provide effective targets for novel fungicides.

RESULTS

Mutants exhibited nutritional growth defects, asexual/sexual developmental abnormalities. Deficiency of FgNup2 resulted in increased resistance of Fusarium graminearum to cell wall disruptors and increased sensitivity to metal ions. Pathogenicity analyses showed that the mutant was significantly less virulent on flowering wheat ears, consistent with the observed decrease in deoxynivalenol (DON) production. Furthermore, we showed that FgNup2 interacts synergistically with FgTri6, a transcription factor of the TRI family, to regulate the expression of toxin-producing genes, which, in turn, affects the biosynthesis of DON and related toxins.

CONCLUSION

This study revealed that FgNup2 plays important roles in the growth and development, cell wall integrity, stress response, pathogenicity, and DON synthesis of F. graminearum. © 2024 Society of Chemical Industry.

Recent advances in chemical synthesis of phosphodiester linkages found in fungal mannans

Fungal mannans are located on the exterior of the fungal cell wall, where they interact with the environment and, ultimately, the human host. Mannans play a major role in shaping the innate immune response to fungal pathogens. Understanding the phosphodiester linkage and mannosyl repeat units in the acid-labile portion of mannans is crucial for comprehending their structure/activity relationships and for development of anti-fungal vaccines and immunomodulators. The phosphodiester linkages connect the acid-stable and acid-labile portions of the mannan polymer. Phosphate groups are attached to positions 4 and/or 6 of mannosyl repeat units in the acid-stable portion and to position 1 of mannosyl repeat units in the acid-labile portion. This review focuses on the synthesis of phosphodiester linkages as an approach to the development of mannan glycomimetics, which are based on natural product fungal mannans. Development of successful synthetic strategies for the phosphodiester linkages may enable the production of mannan glycomimetics that elicit anti-fungal immune responses against existing and emerging fungal pathogens, such as Candida albicans and Candida auris.

Antifungal peptides: Therapeutic potential and challenges before their commercial success

Antifungal peptides (AFPs) are small cationic peptides that are found in a diverse range of taxa including bacteria, plants, mammals and insects. AFPs exhibit the strong antifungal activities against several pathogenic fungi, making them potential candidates for developing novel antifungal agents. AFP cause fungal cell death by rupturing the membranes of the fungal cell wall and inhibits the vital enzymes. Since AFPs are isolated from a range of natural sources, efforts are being made to create synthetic versions of these peptides with improved pharmacological properties. One of their key advantages is that they are less likely to develop resistance as compared to conventional antifungal medications. Although AFPs display immense potential as antifungal agents, challenges still exist in their stability, solubility, absorption, and time-consuming extraction process. Still, the possibility for AFPs to evolve into a novel class of antifungal medicine gives hope for improved treatments for fungal infections. This article offers the comprehensive information on AFPs origin, mode of action, prospective use in antifungal treatments. It also discusses about the application of antifungal peptides beyond the therapeutic field, such as in agriculture for crop protection, in food industry and in aquaculture field. It further elaborates on the challenges and potential paths associated with the progression of AFPs as advanced antifungal agents.

Engineering Adhesion of the Probiotic Strain Escherichia coli Nissle to the Fungal Pathogen Candida albicans

Engineering live biotherapeutic products against fungal pathogens such as Candida albicans has been suggested as a means to tackle the increasing threat of fungal infections and the development of resistance to classical antifungal treatments. One important challenge in the design of live therapeutics is to control their localization inside the human body. The specific binding capability to target organisms or tissues would greatly increase their effectiveness by increasing the local concentration of effector molecules at the site of infection. In this study, we utilized surface display of carbohydrate binding domains to enable the probiotic E. coli Nissle 1917 to adhere specifically to the pathogenic yeast Candida albicans. Binding was quantified using a newly developed method based on the automated analysis of microscopic images. In addition to a rationally selected chitin binding domain, a synthetic peptide of identical length but distinct sequence also conferred binding. Efficient binding was specific to fungal hyphae, the invasive form of C. albicans, while the yeast form, as well as abiotic cellulose and PET particles, was only weakly recognized.

Melanin in fungi: advances in structure, biosynthesis, regulation, and metabolic engineering

Fungi can synthesize a diverse range of melanins with appropriate physicochemical and biological characteristics for numerous applications in health, environmental protection, energy, and industry. Gaining deeper insights into the chemical structures, biosynthetic pathways, and regulatory mechanisms of fungal melanin would establish a basis for metabolic engineering approaches, aimed at enhancing production efficiency and creating custom-designed melanin with desirable material properties. Due to growing interest in their beneficial effects and applications, research on the structure, biosynthesis, and regulation of fungal melanin has significantly advanced. This review highlighted recent progress in fungal melanin production and applications, concentrating on structure, biosynthesis, and regulatory networks, and suggested how an improved understanding of melanin biosynthesis could enable efficient production for future applications.

Mycoremediation of heavy metals by Curvularia lunata from Buckingham Canal, Neelankarai, Chennai

The spread and mobilization of toxic heavy metals in the environment have increased to a harmful level in recent years as a result of the fast industrialization occurring all over the world to meet the demands of a rising population. This research aims to analyze and evaluate the mycoremediation abilities of fungal strains that exhibit tolerance to heavy metals, gathered from water samples at Buckingham Canal, Neelankarai, Chennai. Water samples were examined for heavy metal analysis, and the highest toxic heavy metals, Zn, Pb, Mn, Cu, and Cr, were recorded. Three fungal strains were isolated and named EBPL1000, EBPL1001, and EBPL1002 were selected by primary screening (100 ppm) for further studies. Out of three fungal isolates, EBPL1000 grew in all five heavy metal concentrations and showed 2100 ppm as the highest Maximum Tolerance Concentration toward Lead, 2000 ppm tolerance in Zinc and Manganese, 1700 ppm in Chromium, and 1500 ppm in copper, respectively. The fungal isolate EBPL1000 was identified as Curvularia lunata with 100% percentage identity and query coverage. The Biosorption result reveals that lead is the highest biosorbed heavy metal with 79.99% at 100 ppm concentration while copper is the lowest biosorbed with 24.11% heavy metal at 500 ppm concentration. The uptake of Manganese by Curvularia lunata biomass was the highest (5.64 mg/g) of all heavy metal's uptake at 100 ppm concentration. The lowest uptake of heavy metals was copper (0.43 mg/g) at 500 ppm concentration, and the growth profile study under heavy metals stress conditions shows the order of Pb > Mn > Zn > Cr > Cu at 60 h of time intervals at 100 ppm concentration. In addition to the research, FTIR analysis and Molecular Docking studies provide credence to the idea that Curvularia lunata has high biosorption potential and uptake or removal of toxic heavy metals at low cost and in an eco-friendly way from the contaminated environment.

Recent advances in peptoids as promising antimicrobial agents to target diverse microbial species

The emergence of multidrug-resistant microbial species has become a global health concern, calling for novel antimicrobial agents. Peptoids, a class of synthetic peptidomimetics with unique structural properties, exhibit antimicrobial activity against a broad-spectrum of microbes, in addition to their stability to enzymatic degradation, selectivity, and relative ease of synthesis. Thus, peptoids have great potential in combating various drug-resistant pathogenic microbes. This review provides a comprehensive analysis of the recent advances in utilizing peptoids as effective antimicrobial agents against a wide range of bacteria, fungi, viruses, and parasites. In addition, some of the synthetic strategies and antimicrobial mechanisms are discussed. The imperfections of antimicrobial peptoids and the defects in current antimicrobial peptoids research are pointed out and promising directions for future development in peptoids are highlighted, to pave the way for innovating better antimicrobial peptoids to address the challenges posed by multidrug-resistant microbial species.

Diagnosis and management of invasive fungal diseases by next-generation sequencing: are we there yet?

INTRODUCTION

Invasive fungal diseases (IFDs) are a serious threat to immunocompromised patients. Routine diagnostic methods have limited performance in identifying IFDs. Next-generation sequencing (NGS), including metagenomic NGS (mNGS) and whole-genome sequencing (WGS), recently emerged as diagnostic methods that could provide more accurate and timely diagnoses and management of IFDs.

AREAS COVERED

This article describes the emergence of NGS as a diagnostic tool to address the limitations of current tests. The literature regarding its application and clinical utility in the diagnosis of IFDs is reviewed. Practical considerations, challenges, and opportunities as they relate to the development and implementation of mNGS and WGS for fungal pathogens are discussed.

EXPERT OPINION

NGS emerged over a decade ago with the potential to solve many of the challenges in diagnosing infectious diseases, including IFDs. However, published literature has yielded conflicting data about its clinical utility. The increased clinical adoption of NGS is improving our understanding of how to interpret and use its results to guide actionable decisions. Still, several gaps remain. As the cost, effort, and expertise involved in performing NGS decrease and the reporting of its results becomes standardized, NGS is poised to fill current gaps in the diagnosis of IFDs.

Enhancing Mycoprotein Yield: Metabolic Modulation of Chitin Synthase in Fusarium venenatum

Fusarium venenatum is being extensively utilized for microbial protein production. However, its high dietary fiber content results in substantial carbon loss. Inhibition of chitin biosynthesis presents a promising strategy to improve the mycoprotein yield. Through transcriptomic and bioinformatics analyses, chitin synthase gene FvChs3 was identified as crucial for chitin synthesis in F. venenatum. Knockout of the FvChs3 gene resulted in mycelial expansion and a 26% reduction in the chitin content of strain ΔFvChs3. Ethanol production from fermentation decreased by 47%, while the carbon conversion efficiency and protein conversion increased by 16% and 36%, respectively. Transcriptomic analysis revealed an upregulation of nitrogen metabolism in ΔFvChs3, while genes related to the glycolysis pathway for ethanol synthesis were downregulated. Further knockout of pyruvate decarboxylase gene FvPDC6 in ΔFvChs3 accelerated growth, leading to improvements in carbon and protein conversion of 29% and 40%, respectively. This research lays the foundation for enhancing fungal protein production.

Effects of the Tobacco Defensin NaD1 Against Susceptible and Resistant Strains of Candida albicans

Today, Candida albicans is still the most common cause of both local and life-threatening systemic candidiasis. The spread of resistant fungal strains has resulted in an urgent need to search for new promising antimycotics. Here, we investigated the antifungal action of the tobacco defensin NaD1 against susceptible and resistant to azoles and echinocandins strains of C. albicans. We demonstrated that NaD1 was equally effective and fungicidal against all tested strains. The MIC and MFC values were 6.25 and 12.5 µM, respectively. We showed for the first time that NaD1 could act synergistically not only with caspofungin but also with human host defense antimicrobial peptides cathelicidin LL-37 and β-defensin-2 (HBD2) against susceptible and resistant fungal strains. Using flow cytometry, we demonstrated that NaD1 in combinations with LL-37 or HBD2 can reinforce each other by enhancing membrane disruption. Using the Caco-2 cell monolayer model, we demonstrated that NaD1 impaired the adhesion of C. albicans cells to the human epithelium. Moreover, NaD1 inhibited the formation of fungal biofilms in Sabouraud broth and less markedly in nutrient-rich RPMI-1640 medium, and enhanced the antibiofilm activity of caspofungin. Thus, we hypothesized that NaD1 might affect the development of candidiasis in vivo, including that caused by resistant fungal strains.

Candida albicans-Derived β-Glucan as a Novel Modulator of Tumor Microenvironment: Targeting Macrophage Polarization and Inducing Ferroptosis in Lung Cancer

Introduction

Tumor-associated macrophages (TAMs) play a crucial role in the tumor microenvironment (TME), and their polarization state significantly influences patient outcomes. This study investigates the inhibitory effects of β-glucan extracted from Candida albicans on lung cancer progression, focusing on its impact on TAM polarization and the induction of ferroptosis, a form of regulated cell death.

Methods

Utilizing both in vivo animal models and in vitro cellular assays, we assessed the impact of β-glucan on tumor growth, cellular proliferation, and migration. We evaluated TAM polarization by analyzing the expression of M1 and M2 markers and identified differentially expressed genes (DEGs) related to ferroptosis. The role of ferroptosis in TAM polarization was further confirmed by assessing the protein levels of ACSL4 and GPX4, intracellular ferrous ion levels, and lipid peroxides.

Results

β-glucan treatment significantly reduced tumor size and weight, along with cellular proliferation and migration, suggesting a potent suppressive effect on lung cancer cell growth. β-glucan promoted an M1-like phenotype in TAMs, as evidenced by increased CD86 expression and decreased CD206 expression, and modulated cytokine mRNA levels. RNA sequencing analysis post β-glucan treatment identified a substantial number of DEGs enriched in the ferroptosis pathway. The induction of ferroptosis by β-glucan was further confirmed through the significant upregulation of ACSL4 and downregulation of GPX4, alongside increased intracellular ferrous ion levels and lipid peroxides. The ferroptosis inhibitor Fer-1 abrogated these effects, highlighting the specificity of β-glucan-mediated polarization.

Conclusion

These results collectively provide novel insights into the immunotherapeutic potential of β-glucan from Candida albicans and its role in modulating TAM polarization and lung cancer growth, offering a promising avenue for cancer treatment strategies.

β-1,6-Glucan plays a central role in the structure and remodeling of the bilaminate fungal cell wall

The cell wall of human fungal pathogens plays critical roles as an architectural scaffold and as a target and modulator of the host immune response. Although the cell wall of the pathogenic yeast Candida albicans is intensively studied, one of the major fibrillar components in its cell wall, β-1,6-glucan, has been largely neglected. Here, we show that β-1,6-glucan is essential for bilayered cell wall organization, cell wall integrity, and filamentous growth. For the first time, we show that β-1,6-glucan production compensates the defect in mannan elongation in the outer layer of the cell wall. In addition, β-1,6-glucan dynamics are also coordinated by host environmental stimuli and stresses with wall remodeling, where the regulation of β-1,6-glucan structure and chain length is a crucial process. As we point out that β-1,6-glucan is exposed at the yeast surface and modulate immune response, β-1,6-glucan must be considered a key factor in host-pathogen interactions.

Role of cell membrane homeostasis in the pathogenicity of pathogenic filamentous fungi

The cell membrane forms a fundamental part of all living cells and participates in a variety of physiological processes, such as material exchange, stress response, cell recognition, signal transduction, cellular immunity, apoptosis, and pathogenicity. Here, we review the mechanisms and functions of the membrane structure (lipid components of the membrane and the biosynthesis of unsaturated fatty acids), membrane proteins (transmembrane proteins and proteins contributing to membrane curvature), transcriptional regulation, and cell wall components that influence the virulence and pathogenicity of filamentous fungi.

Streptomyces griseus Versus Trichoderma viride Chitinase as an Anti-inflammatory and Antifungal Agent Against Human Pathogenic Fungi

Fungal pathogens cause over a billion human infections annually, leading to more than 1.6 million deaths each year. The scarcity of available antifungal drugs intensifies the public health threat posed by human pathogenic fungal infections. Therefore there is a critical demand for novel, safe, and effective antifungal agents. Although chitinases are established as effective antifungal agents against phytopathogenic fungi, research on their activity against human pathogenic fungi is limited. The present study seeks to investigate the anti-inflammatory and antifungal activity of bacterial and fungal chitinase against human pathogenic fungi. The antifungal efficacy of bacterial chitinase from Streptomyces griseus, fungal chitinase from Trichoderma viride, and a combination of both was determined by calculating the inhibition percentage in fungal growth, indicated by the reduction in the dry mass of the fungi. Additionally, the anti-inflammatory activity of these chitinases was assessed by measuring the inhibition of albumin denaturation. Results revealed that chitinases exhibited greater antifungal activity compared to the standard. Notably, bacterial chitinase demonstrated higher effectiveness than fungal chitinase against Aspergillus fumigatus, while the bacterial and fungal chitinase had similar effects against different Cryptococcus neoformans and Candida species. The combination of bacterial and fungal chitinase demonstrated the highest antifungal activity against all tested fungi. Furthermore, the anti-inflammatory activity indicated that chitinases prevented 98% of albumin denaturation, marking the first study reporting the anti-inflammatory role of chitinases in preventing albumin denaturation. Additional in-vivo studies are necessary to explore the antifungal activity of chitinases against human pathogenic fungi and investigate the anti-inflammatory mechanisms of chitinase.

Effects of global change drivers on the expression of pathogenicity and stress genes in dryland soil fungi

The impacts of global climate change on dryland fungi have been understudied even though fungi are extremely sensitive to changes in the environment. Considering that many fungi are pathogens of plants and animals, including humans, their responses to anthropogenic change could have important implications for public health and food security. In this study, we investigated the potential physiological responses (i.e., metatranscriptomics) of pathogenicity and stress in dryland fungi exposed to global change drivers, drought, and the physical disturbance associated with land use. Specifically, we wanted to assess if there was an increase in the transcription of genes associated to pathogenicity and stress in response to global change drivers. In addition, we wanted to investigate which pathogenicity and stress genes were consistently differentially expressed under the different global change conditions across the heterogeneous landscape (i.e., microsite) of the Chihuahuan desert. We observed increased transcription of pathogenicity and stress genes, with specific genes being most upregulated in response to global change drivers. Additionally, climatic conditions linked to different microsites, such as those found under patches of vegetation, may play a significant role. We provide evidence supporting the idea that environmental stress caused by global change could contribute to an increase of pathogenicity as global climate changes. Specifically, increases in the transcription of stress and virulence genes, coupled with variations in gene expression, could lead to the onset of pathogenicity. Our work underscores the importance of studying dryland fungi exposed to global climate change and increases in existing fungal pathogens, as well as the emergence of new fungal pathogens, and consequences to public health and food security.

IMPORTANCE

The effects of global climate change on dryland fungi and consequences to our society have been understudied despite evidence showing that pathogenic fungi increase in abundance under global climate change. Moreover, there is a growing concern that global climate change will contribute to the emergence of new fungal pathogens. Yet, we do not understand what mechanisms might be driving this increase in virulence and the onset of pathogenicity. In this study, we investigate how fungi respond to global change drivers, physical disturbance, and drought, in a dryland ecosystem in terms of pathogenicity and stress. We find that indeed, under global change drivers, there is an increase in the transcription and expression of genes associated to pathogenicity and stress, but that microclimatic conditions matter. Our study shows the importance of investigating dryland fungi exposed to global climate change and impacts on our society, which may include threats to public health and food security.

Global characterization of GH11 family xylanases genes in Neostagonosporella sichuanensis and functional analysis of Nsxyn1 and Nsxyn2

Rhombic-spot disease, caused mainly by Neostagonosporella sichuanensis, significantly impacts the yield and quality of fishscale bamboo (Phyllostachys heteroclada). Xylanases are essential for pathogenic fungi infection, yet their specific functions in the physiology and pathogenicity of N. sichuanensis remain unclear. Here, we characterized three xylanase proteins with glycosyl hydrolase 11 domains from the N. sichuanensis SICAUCC 16-0001 genome and examined the function of Nsxyn1 and Nsxyn2. Purified Nsxyn1 and Nsxyn2 proteins displayed specific xylanase activity in vitro and induced cell death in Nicotiana benthamiana, independent of their enzymatic function. Both proteins possessed signal peptides and were confirmed as secreted proteins using a yeast secretion system. Subcellular localization revealed that Nsxyn1 and Nsxyn2 localized in both the cytoplasm and nucleus and can trigger cell death in N. benthamiana through Agrobacterium tumefaciens-mediated transient transformation. qRT-PCR results showed notable upregulation of Nsxyn1 and Nsxyn2 during infection, with Nsxyn1 exhibiting an 80-fold increase at 15 days post-inoculation. Deletion of Nsxyn1 and Nsxyn2 in N. sichuanensis impaired xylan degradation, adaptation to osmotic and oxidative stress, and pathogenic full virulence. Deletion of Nsxyn1 notably slowed fungal growth and reduced spore production, whereas only a reduction in microconidial production was observed in Nsxyn2 mutants. Complementation of Nsxyn1 and Nsxyn2 only partially restored these phenotypic defects in the ∆Nsxyn1 and ∆Nsxyn2 mutants. These findings suggest that Nsxyn1 and Nsxyn2 contribute to N. sichuanensis virulence and induced plant defense responses, providing new insights into the function of xylanases in the interaction between fishscale bamboo and N. sichuanensis.

Roles of Different Signaling Pathways in Cryptococcus neoformans Virulence

Cryptococcus neoformans is a widespread fungal pathogen that can infect the human central nervous system (CNS) and cause fungal meningitis, leading to hundreds of thousands of deaths worldwide each year. Previous studies have demonstrated that many signal transduction pathways are crucial for the morphological development and virulence of C. neoformans. In this review, data from over 116 research articles have been compiled to show that many signaling pathways control various characteristics of C. neoformans, individually or in association with other pathways, and to establish strong links among them to better understand C. neoformans pathogenesis. Every characteristic of C. neoformans is closely linked to these signaling pathways, making this a rich area for further research. It is essential to thoroughly explore these pathways to address questions that remain and apply a molecular mechanistic approach to link them. Targeting these pathways is crucial for understanding the exact mechanism of infection pathogenesis and will facilitate the development of antifungal drugs as well as the diagnosis and prevention of cryptococcosis.

Development of a whole-cell SELEX process to select species-specific aptamers against Aspergillus niger

BACKGROUND

Spores produced by the filamentous fungus Aspergillus niger are abundant in a variety of environments. The proliferation of this fungus in indoor environments has been associated to health risks and its conidia can cause allergic reaction and severe invasive disease in animals and humans. Therefore, the detection and monitoring of Aspergillus conidia is of utmost importance to prevent serious fungal infections and contaminations. Among others, aptamers could serve as biosensors for the specific detection of fungal spores.

RESULTS

In this study, DNA aptamers specific to conidia of A. niger were developed by optimizing a whole-cell SELEX approach. Three whole-cells SELEX experiments were performed in parallel with similar conditions. Quantification of recovered ssDNA and melting curve analyses were applied to monitor the ongoing SELEX process. Next-generation sequencing was performed on selected recovered ssDNA pools, allowing the identification of DNA aptamers which bind with high affinity to the target cells. The developed aptamers were shown to be species-specific, being able to bind to A. niger but not to A. tubingensis or to A. nidulans. The binding affinity of two aptamers (AN01-R9-006 and AN02-R9-185) was measured to be 58.97 nM and 138.71 nM, respectively, which is in the range of previously developed aptamers.

CONCLUSIONS

This study demonstrates that species-specific aptamers can be successfully developed via whole-cell SELEX to distinguish different Aspergillus species and opens up new opportunities in the field of diagnostics of fungal infections.

The pathobiology of human fungal infections

Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.

A water-soluble mycelium polysaccharide from Monascus pilosus: Extraction, structural characterization, immunomodulatory effect and yield enhanced by overexpression of UGE gene

Mycelium polysaccharide (MPP) from Monascus pilosus with the compositions of glucose, galactose, mannose, glucosamine hydrochloride, rhamnose and arabinose, was obtained using alkaline extracting, and subsequently three purified components (MPP-0, MPP-0.1 and MPP-0.3) were separated. The purity and extraction volume of the MPP-0.1 fraction surpassed those of the other two groups, thus warranting its selection for subsequent experimental investigations. The sample MPP-0.1, with an average molecular weight of 3.7776 × 104 Da, exhibited exceptional thermal stability up to 170 °C. The main glycosidic linkage pattern of MPP-0.1 was structured as→[4)-α-D-Glcp-(1]6 → 4)-α-D-Glcp-(1 → [2)-α-D-Manp-(1]5 → 2)-α-D-Manp-(1 → 5)-β-D-Galf-(1 → 3)-β-D-Galf (1 → 3)-β-D-Galf-(1 → 3)-β-D-Galf-(1→, and branched Glcp, Manp, Galf fragments were connected with the main chain through →4, 6)-α-D-Glcp-(1→, →2, 6)-α-D-Manp-(1 → and →3, 6)-β-D-Galf-(1→. Besides, the up-regulated levels of Nitric oxide (NO), Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and other pro-inflammatory cytokines along with increased phagocytic activity revealed that MPP-0.1 has significant immunomodulatory effect, and can significantly enhance the proliferation and activation of RAW264.7 cells. Finally, the gene UGE (UDP-glucose 4-epimerase) was overexpressed in M. pilosus to increase the MPP production. Results showed that the biomass of the recombinant strain exhibited a remarkable increase of approximately 62.56 ± 1.50 % compared to that of the parental strain, and the extraction yield of MPP increased significantly by 83.19 ± 4.56 %.

Antimicrobial peptide AMP-17 induces protection against systemic candidiasis and interacts synergistically with fluconazole against Candida albicans biofilm

Candida albicans, a common commensal and opportunistic fungal pathogen in humans, can occasionally progress to disseminated candidiasis which is a serious condition with a high morbidity and fatality rate. The emergence of drug-resistant fungal strains compels us to look for an efficient treatment solution. Our earlier studies have demonstrated that the unique antimicrobial peptide AMP-17 from Musca domestica has a strong antifungal impact on C. albicans in vitro. Here, we verified the therapeutic effects of AMP-17 on systemic candidiasis in vivo and the peptide interacts with fluconazole, a common antifungal medication, to treat systemic candidiasis. In the disseminated candidiasis model of Galleria mellonella and mice challenged with C. albicans, AMP-17 increased the survival rates of infected larvae and mice to 66.7 and 75%, respectively. Furthermore, the peptide lowered the load of C. albicans in the infected larvae and the kidneys of the mice by nearly 90%. Additional histological examination and measurements of plasma cytokines showed that the injection of AMP-17 markedly reduced the inflammatory response and balanced cytokine expression. Furthermore, checkerboard micro dilution experiments demonstrated that AMP-17 and fluconazole worked in synergy to inhibit C. albicans in the biofilm mode. According to morphological studies, AMP-17 and fluconazole together decreased the production of hyphae throughout the C. albicans biofilm formation process, loosening the mature biofilms' structure and lowering the amount of carbohydrates in the extracellular matrix (ECM) of the biofilms. Taken together, these results showed that AMP-17 would be a viable treatment for systemic candidiasis and might be a different approach to combating Candida biofilm, either by itself or in conjunction with fluconazole.

The influence of the pectin structure on the properties of hydrogel dressings doped with octenidine-containing antiseptic

This article presents a method for producing hydrogel dressings using high methylated pectin from apples or citrus, doped with the antiseptic agent, octenidine dihydrochloride. Octenidine was incorporated in-situ during the polymer crosslinking. The pectins were characterized by their varying molecular weight characteristics, monosaccharide composition, and degree of esterification (DE). The study assessed the feasibility of producing biologically active hydrogels with pectin and delved into how the polymer's characteristics affect the properties of the resulting dressings. The structure evaluation of hydrogel materials showed interactions between individual components of the system and their dependence on the type of used pectin. Both the antimicrobial properties and cytotoxicity of the dressings were evaluated. The results suggest that the primary determinants of the functional attributes of the hydrogels are the molecular weight characteristics and the DE of the pectin. As these values rise, there is an increase in polymer-polymer interactions, overshadowing polymer-additive interactions. This intensification strengthens the mechanical and thermal stability of the hydrogels and enhances the release of active components into the surrounding environment. Biological evaluations demonstrated the ability of octenidine to be released from the dressings and effectively inhibit the growth of microbial pathogens.

Label-Free Optical Transmission Tomography for Direct Mycological Examination and Monitoring of Intracellular Dynamics

Live-cell imaging generally requires pretreatment with fluorophores to either monitor cellular functions or the dynamics of intracellular processes and structures. We have recently introduced full-field optical coherence tomography for the label-free live-cell imaging of fungi with potential clinical applications for the diagnosis of invasive fungal mold infections. While both the spatial resolution and technical set up of this technology are more likely designed for the histopathological analysis of tissue biopsies, there is to our knowledge no previous work reporting the use of a light interference-based optical technique for direct mycological examination and monitoring of intracellular processes. We describe the first application of dynamic full-field optical transmission tomography (D-FF-OTT) to achieve both high-resolution and live-cell imaging of fungi. First, D-FF-OTT allowed for the precise examination and identification of several elementary structures within a selection of fungal species commonly known to be responsible for invasive fungal infections such as Candida albicans, Aspergillus fumigatus, or Rhizopus arrhizus. Furthermore, D-FF-OTT revealed the intracellular trafficking of organelles and vesicles related to metabolic processes of living fungi, thus opening new perspectives in fast fungal infection diagnostics.

Alligamycin A, an antifungal β-lactone spiroketal macrolide from Streptomyces iranensis

Fungal infections pose a great threat to public health and there are only four main types of antifungal drugs, which are often limited with toxicity, drug-drug interactions and antibiotic resistance. Streptomyces is an important source of antibiotics, represented by the clinical drug amphotericin B. Here we report the discovery of alligamycin A (1) as an antifungal compound from the rapamycin-producer Streptomyces iranensis through genome-mining, genetics and natural product chemistry approaches. Alligamycin A harbors a unique chemical scaffold with 13 chiral centers, featuring a β-lactone moiety, a [6,6]-spiroketal ring, and an unreported 7-oxo-octylmalonyl-CoA extender unit incorporated by a potential crotonyl-CoA carboxylase/reductase. It is biosynthesized by a type I polyketide synthase which is confirmed through CRISPR-based gene editing. Alligamycin A displayed potent antifungal effects against numerous clinically relevant filamentous fungi, including resistant Aspergillus and Talaromyces species. β-Lactone ring is essential for the antifungal activity since alligamycin B (2) with disruption in the ring abolished the antifungal effect. Proteomics analysis revealed alligamycin A potentially disrupts the integrity of fungal cell walls and induces the expression of stress-response proteins in Aspergillus niger. Discovery of the potent antifungal candidate alligamycin A expands the limited antifungal chemical space.

Anti-fungal peptides: an emerging category with enthralling therapeutic prospects in the treatment of candidiasis

Candida infections, particularly invasive candidiasis, pose a serious global health threat. Candida albicans is the most prevalent species causing candidiasis, and resistance to key antifungal drugs, such as azoles, echinocandins, polyenes, and fluoropyrimidines, has emerged. This growing multidrug resistance (MDR) complicates treatment options, highlighting the need for novel therapeutic approaches. Antifungal peptides (AFPs) are gaining recognition for their potential as new antifungal agents due to their diverse structures and functions. These natural or recombinant peptides can effectively target fungal virulence and viability, making them promising candidates for future antifungal development. This review examines infections caused by Candida species, the limitations of current antifungal treatments, and the therapeutic potential of AFPs. It emphasizes the importance of identifying novel AFP targets and their production for advancing treatment strategies. By discussing the therapeutic development of AFPs, the review aims to draw researchers' attention to this promising field. The integration of knowledge about AFPs could pave the way for novel antifungal agents with broad-spectrum activity, reduced toxicity, targeted action, and mechanisms that limit resistance in pathogenic fungi, offering significant advancements in antifungal therapeutics.

Transcriptomic analyses of bacterial growth on fungal necromass reveal different microbial community niches during degradation

Bacteria are major drivers of organic matter decomposition and play crucial roles in global nutrient cycling. Although the degradation of dead fungal biomass (necromass) is increasingly recognized as an important contributor to soil carbon (C) and nitrogen (N) cycling, the genes and metabolic pathways involved in necromass degradation are less characterized. In particular, how bacteria degrade necromass containing different quantities of melanin, which largely control rates of necromass decomposition in situ, is largely unknown. To address this gap, we conducted a multi-timepoint transcriptomic analysis using three Gram-negative, bacterial species grown on low or high melanin necromass of Hyaloscypha bicolor. The bacterial species, Cellvibrio japonicus, Chitinophaga pinensis, and Serratia marcescens, belong to genera known to degrade necromass in situ. We found that while bacterial growth was consistently higher on low than high melanin necromass, the CAZyme-encoding gene expression response of the three species was similar between the two necromass types. Interestingly, this trend was not shared for genes encoding nitrogen utilization, which varied in C. pinensis and S. marcescens during growth on high vs low melanin necromass. Additionally, this study tested the metabolic capabilities of these bacterial species to grow on a diversity of C and N sources and found that the three bacteria have substantially different utilization patterns. Collectively, our data suggest that as necromass changes chemically over the course of degradation, certain bacterial species are favored based on their differential metabolic capacities.IMPORTANCEFungal necromass is a major component of the carbon (C) in soils as well as an important source of nitrogen (N) for plant and microbial growth. Bacteria associated with necromass represent a distinct subset of the soil microbiome and characterizing their functional capacities is the critical next step toward understanding how they influence necromass turnover. This is particularly important for necromass varying in melanin content, which has been observed to control the rate of necromass decomposition across a variety of ecosystems. Here we assessed the gene expression of three necromass-degrading bacteria grown on low or high melanin necromass and characterized their metabolic capacities to grow on different C and N substrates. These transcriptomic and metabolic studies provide the first steps toward assessing the physiological relevance of up-regulated CAZyme-encoding genes in necromass decomposition and provide foundational data for generating a predictive model of the molecular mechanisms underpinning necromass decomposition by soil bacteria.

The Endocytosis Adaptor Sla1 Facilitates Drug Susceptibility and Fungal Pathogenesis Through Sla1-Efg1 Regulating System in Candida albicans

Introduction

The role of endocytosis in Candida albicans drug-resistance and pathogenicity remains poorly understood, despite its importance as a fundamental component of intracellular trafficking.

Objective

In order to understand the role of endocytosis in Candida albicans cell wall integrity, drug resistance, and virulence.

Methods

Detection of intracellular endocytosis by FM4-64 staining; Scanning electron microscopy is used to detect cell wall components; Spot assay for detecting drug sensitivity; Co-ip is used to detect protein interactions.

Results

In this study, we found the functions of Sla1 in regulating endocytosis is conserved among pathogenic fungi. Our results also revealed that the deletion of the SLA1 gene altered cell wall properties, composition, and gene expression. In addition, we showed that C. albicans Sla1 was responsible for hyphal development in vitro and for fungal pathogenicity in a murine infection model. Intriguingly, sla1∆/∆ mutant demonstrated enhanced drug resistance, and Sla1 was found to interact with the transcription factor Efg1; the relationship between Sla1 and Efg1 impacts the expression of genes encoding components of the ergosterol biosynthesis pathway, including ERG1, EGR11, and ERG25.

Discussion

These findings have expanded our knowledge of the capabilities of Sla1 beyond its role as an endocytosis adapter and provided insights into a potential new therapeutic target for the treatment of fungal infections.

Clioquinol influences cell membrane, attenuates virulence factors, induces apoptosis to inhibit Candida albicans growth

Aim: To investigate the antifungal mechanism of clioquinol and indicate that clioquinol has potential as a novel therapeutic antifungal agent.Materials & methods: Analyze differentially expressed genes of Candida albicans treated with clioquinol using RNA-sequencing. The effects on cell wall and membrane features, virulence factors, apoptosis-induced cell death were also investigated.Results: The differentially expressed genes of C. albicans after treated with clioquinol focused on cell wall and membrane synthesis, antioxidant system and energy metabolism. Clioquinol did not change cell wall components levels while it decreased squalene epoxidase activity to influence the ergosterol biosynthesis in cell membrane. It also decreased cellular surface hydrophobicity and induced β-glucan unmasking to attenuate virulence factors. Meanwhile, clioquinol influenced enzyme activities involved in antioxidant system, citrate cycle, oxidative phosphorylation and decreased the ATP levels. Clioquinol induced apoptosis in C. albicans to exert its fungicidal activity. It induced reactive oxygen species and calcium ion elevation, leading to loss of mitochondrial membrane potential, cytochrome C release, metacaspase activation, thereby triggering apoptosis.Conclusion: Clioquinol exerted anti-C. albicans activity through influencing cell membrane, attenuating virulence factors and inducing apoptosis.

Expansion microscopy reveals characteristic ultrastructural features of pathogenic budding yeast species

Candida albicans is the most prevalent fungal pathogen associated with candidemia. Similar to other fungi, the complex life cycle of C. albicans has been challenging to study with high-resolution microscopy due to its small size. Here, we employed ultrastructure expansion microscopy (U-ExM) to directly visualise subcellular structures at high resolution in the yeast and during its transition to hyphal growth. N-hydroxysuccinimide (NHS)-ester pan-labelling in combination with immunofluorescence via snapshots of various mitotic stages provided a comprehensive map of nucleolar and mitochondrial segregation dynamics and enabled the resolution of the inner and outer plaque of spindle pole bodies (SPBs). Analyses of microtubules (MTs) and SPBs suggest that C. albicans displays a side-by-side SPB arrangement with a short mitotic spindle and longer astral MTs (aMTs) at the pre-anaphase stage. Modifications to the established U-ExM protocol enabled the expansion of six other human fungal pathogens, revealing that the side-by-side SPB configuration is a plausibly conserved feature shared by many fungal species. We highlight the power of U-ExM to investigate subcellular organisation at high resolution and low cost in poorly studied and medically relevant microbial pathogens.

Nanomaterial-based therapeutics for enhanced antifungal therapy

The application of nanotechnology in antifungal therapy is gaining increasing attention. Current antifungal drugs have significant limitations, such as severe side effects, low bioavailability, and the rapid development of resistance. Nanotechnology offers an innovative solution to address these issues. This review discusses three key strategies of nanotechnology to enhance antifungal efficacy. Firstly, nanomaterials can enhance their interaction with fungal cells via ingenious surface tailoring of nanomaterials. Effective adhesion of nanoparticles to fungal cells can be achieved by electrostatic interaction or specific targeting to the fungal cell wall and cell membrane. Secondly, stimuli-responsive nanomaterials are developed to realize smart release of drugs in the specific microenvironment of pathological tissues, such as the fungal biofilm microenvironment and inflammatory microenvironment. Thirdly, nanomaterials can be designed to cross different physiological barriers, effectively addressing challenges posed by skin, corneal, and blood-brain barriers. Additionally, some new nanomaterial-based strategies in treating fungal infections are discussed, including the development of fungal vaccines, modulation of macrophage activity, phage therapy, the application of high-throughput screening in drug discovery, and so on. Despite the challenges faced in applying nanotechnology to antifungal therapy, its significant potential and innovation open new possibilities for future clinical antifungal applications.

The Ubiquitous Wilt-Inducing Pathogen Fusarium oxysporum-A Review of Genes Studied with Mutant Analysis

Fusarium oxysporum is one of the most economically important plant fungal pathogens, causing devastating Fusarium wilt diseases on a diverse range of hosts, including many key crop plants. Consequently, F. oxysporum has been the subject of extensive research to help develop and improve crop protection strategies. The sequencing of the F. oxysporum genome 14 years ago has greatly accelerated the discovery and characterization of key genes contributing to F. oxysporum biology and virulence. In this review, we summarize important findings on the molecular mechanisms of F. oxysporum growth, reproduction, and virulence. In particular, we focus on genes studied through mutant analysis, covering genes involved in diverse processes such as metabolism, stress tolerance, sporulation, and pathogenicity, as well as the signaling pathways that regulate them. In doing so, we hope to present a comprehensive review of the molecular understanding of F. oxysporum that will aid the future study of this and related species.

Biogenic Synthesis of Silver Nanoparticles Mediated by Aronia melanocarpa and Their Biological Evaluation

In the present study, two A. melanocarpa berry extracts were used for the synthesis of silver nanoparticles (AgNPs). After the optimization of synthesis, the AgNPs were characterized using UV-Vis, FTIR, EDX, DLS, and STEM analyses. The stability in different media, phytotoxicity, as well as antimicrobial and antioxidant activities were also evaluated. The ideal synthesis conditions were represented by a 3 mM AgNO3 concentration, 1:9 extract:AgNO3 volume ratio, alkaline medium, and stirring at 40 °C for 120 min. The synthesis was confirmed by the surface plasmon resonance (SPR) peak at 403 nm, and the strong signal at 3 keV from the EDX spectra. FTIR analysis indicated that polyphenols, polysaccharides, and amino acids could be the compounds responsible for synthesis. Stability tests and the negative zeta potential values showed that phytocompounds also play a role in the stabilization and capping of AgNPs. The preliminary phytotoxicity studies on T. aestivum showed that both the extracts and their corresponding AgNPs had an impact on the growth of roots and shoots as well as on the microscopic structure of leaves. The synthesized AgNPs presented antimicrobial activity against S. aureus, E. coli, and C. albicans. Moreover, considering the results obtained in the lipoxygenase inhibition, the DPPH and hydroxyl scavenging activities, and the ferrous ion chelating assay, AgNPs exhibit promising antioxidant activity.

Candida albicans N-Linked Mannans Potentiate the Induction of Trained Immunity via Dectin-2

The interaction between the Candida albicans cell wall and pattern recognition receptors is crucial for the initiation of host immune responses, which, ultimately, contribute to the clearance of this pathogenic fungus. In the present study, we investigate the ability of C. albicans mannans to modulate immune response and induce innate immune memory (also termed trained immunity). Using mutants of C. albicans that are defective in or lack mannosyl residues, we show that alterations in the mannosylation of the C. albicans cell wall affect the innate cytokine response and strongly reduce the secretion of T-cell-derived cytokines. Subsequently, we demonstrate that the branching of N-linked mannan, but not O-linked mannan, is essential to potentiate the induction of trained immunity, a process mediated by dectin 2. In conclusion, N-linked mannan is needed, in addition to β-glucans, for an effective induction of trained immunity by C. albicans.

Biochemical Characterization and Disease Control Efficacy of Pleurotus eryngii-Derived Chitosan-An In Vivo Study against Monilinia laxa, the Causal Agent of Plum Brown Rot

Chitin (Ct) is a crucial biopolymer present in fungi, algae, arthropods, and is usually obtained from crustacean shells. Chitosan (Cs) is a derivative from Ct deacetylation, and possesses numerous uses in various agro-industrial fields. Research on fungal-derived Ct and Cs is mostly focused on pharmaceutical uses, however their uses for plant disease control remain less explored. The main objective of the current study is to evaluate the possibility of using chitosan obtained from mushroom Pleurotus eryngii (Cs-Pe) for controlling some phytopathogens compared to commercial chitosan (C.Cs). This study is focused on the following key areas: (i) extracting Ct from P. eryngii mycelium and converting it to Cs through deacetylation, using both bleaching and non-bleaching methods; (ii) conducting a physico-chemical characterization and in vitro evaluation of the antimicrobial activity of the obtained Cs; (iii) performing an in vivo assessment of the phytotoxic and cytotoxic effects of Cs; and (iv) investigating in vivo the impact of the studied chitosan on fruit quality and its biocontrol efficacy against Monilinia laxa infections in plum fruits. Results showed that Cs-Pe, especially the unbleached one, displayed promising in vitro antimicrobial activity against the majority of tested pathogens. Regarding the cytotoxicity, the highest significant increase in cell abnormality percentage was observed in the case of C.Cs compared to Cs-Pe. In the in vivo study, Cs-Pe acted as a protective barrier, lowering and/or preventing moisture loss and firmness of treated plums. The studied Cs-Pe demonstrated notable efficacy against M. laxa which decreased the fruits' percentage decline. These results strongly suggest that Cs derived from P. eryngii is a potential candidate for increasing plums' shelf-life. This research shed light on the promising applications of P. eryngii-derived Cs in the agri-food field.

Unveiling Drimenol: A Phytochemical with Multifaceted Bioactivities

Drimenol, a phytochemical with a distinct odor is found in edible aromatic plants, such as Polygonum minus (known as kesum in Malaysia) and Drimys winteri. Recently, drimenol has received increasing attention owing to its diverse biological activities. This review offers the first extensive overview of drimenol, covering its sources, bioactivities, and derivatives. Notably, drimenol possesses a wide spectrum of biological activities, including antifungal, antibacterial, anti-insect, antiparasitic, cytotoxic, anticancer, and antioxidant effects. Moreover, some mechanisms of its activities, such as its antifungal effects against human mycoses and anticancer activities, have been investigated. However, there are still several crucial issues in the research on drimenol, such as the lack of experimental understanding of its pharmacokinetics, bioavailability, and toxicity. By synthesizing current research findings, this review aims to present a holistic understanding of drimenol, paving the way for future studies and its potential utilization in diverse fields.

Novel domain-structure-containing chitinases A and B of Bacillus velezensis produced by recombinant Escherichia coli cells: Synergism on chitin degradation and their potential in suppressing Candida albicans cell germination

Bacillus velezensis RB.IBE29 harbors two chitinases belonging to the glycoside hydrolase family 18 and exhibiting a novel domain structure. The roles of these chitinases in crop production have been reported; nevertheless, their contribution to controlling human pathogens is unknown. In this initial work, the chitinases A (BvChiA) and B (BvChiB) of strain RB.IBE29 were produced in recombinant Escherichia coli BL21-CodonPlus (DE3)-RIPL cells and subsequently purified using HisTrap FF column. The purified BvChiA and BvChiB exhibited the highest chitinase and binding activities against colloidal chitin. Combining both chitinases for the hydrolysis of powdered chitin increased the reducing sugar content by 88.7 %. Moreover, the purified chitinases remarkably suppressed the germination of Candida albicans VTCC 20568 (=JCM 2070) cells. These results indicated that the novel domain-structure-containing chitinases of strain RB.IBE29 have great potential and can be further developed as a novel therapeutic agent against human pathogenic C. albicans.

Exploring the potential of chitin and chitosan in nanobiocomposites for fungal immunological detection and antifungal action

Chitin is a polymer of N-acetylglucosamine and an essential component of the fungal cell wall. Chitosan is the deacetylated form of chitin and is also important for maintaining the integrity of this structure. Both polysaccharides are widely distributed in nature and have been shown to have a variety of applications in biomedicine, including their potential in immune sensing and as potential antifungal agents. In addition, chitin has been reported to play an important role in the pathogen-host interaction, involving innate and adaptive immune responses. This paper will explore the role of chitin and chitosan when incorporated into nanobiocomposites to improve their efficacy in detecting fungi of medical interest and inhibiting their growth. Potential applications in diagnostic and therapeutic medicine will be discussed, highlighting their promise in the development of more sensitive and effective tools for the early diagnosis of fungal infections. This review aims to highlight the importance of the convergence of nanotechnology and biology in addressing public health challenges.

Uniqueness of Candida auris cell wall in morphogenesis, virulence, resistance, and immune evasion

Candida auris has drawn global attention due to its alarming multidrug resistance and the emergence of pan resistant strains. C. auris poses a significant risk in nosocomial candidemia especially among immunocompromised patients. C. auris showed unique virulence characteristics associated with cell wall including cell polymorphism, adaptation, endurance on inanimate surfaces, tolerance to external conditions, and immune evasion. Notably, it possesses a distinctive cell wall composition, with an outer mannan layer shielding the inner 1,3-β glucan from immune recognition, thereby enabling immune evasion and drug resistance. This review aimed to comprehend the association between unique characteristics of C. auris's cell wall and virulence, resistance mechanisms, and immune evasion. This is particularly relevant since the fungal cell wall has no human homology, providing a potential therapeutic target. Understanding the complex interactions between the cell wall and the host immune system is essential for devising effective treatment strategies, such as the use of repurposed medications, novel therapeutic agents, and immunotherapy like monoclonal antibodies. This therapeutic targeting strategy of C. auris holds promise for effective eradication of this resilient pathogen.

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.

Lignin/Surfactin Coacervate as an Eco-Friendly Pesticide Carrier and Antifungal Agent against Phytopathogen

Excessive usage of biologically toxic fungicides and their matrix materials poses a serious threat to public health. Leveraging fungicide carriers with inherent pathogen inhibition properties is highly promising for enhancing fungicide efficacy and reducing required dosage. Herein, a series of coacervates have been crafted with lignin and surfactin, both of which are naturally derived and demonstrate substantial antifungal properties. This hierarchically assembled carrier not only effectively loads fungicides with a maximum encapsulation efficiency of 95% but also stably deposits on hydrophobic leaves for high-speed impacting droplets. Intriguingly, these coacervates exhibit broad spectrum fungicidal activity against eight ubiquitous phytopathogens and even act as a standalone biofungicide to replace fungicides. This performance can significantly reduce the fungicide usage and be further strengthened by an encapsulated fungicide. The inhibition rate reaches 87.0% when 0.30 mM pyraclostrobin (Pyr) is encapsulated within this coacervate, comparable to the effectiveness of 0.80 mM Pyr alone. Additionally, the preventive effects against tomato gray mold reached 53%, significantly surpassing those of commercial adjuvants. Thus, it demonstrates that utilizing biosurfactants and biomass with intrinsic antifungal activity to fabricate fully biobased coacervates can synergistically combine the functions of a fungicide carrier and antifungal agent against phytopathogens and guarantee environmental friendliness. This pioneering approach provides deeper insights into synergistically enhancing the effectiveness of agrochemicals from multiple aspects, including fungicide encapsulation, cooperative antifungal action, and droplet deposition.

A Novel Preservative Film with a Pleated Surface Structure and Dual Bioactivity Properties for Application in Strawberry Preservation due to Its Efficient Apoptosis of Pathogenic Fungal Cells

Botrytis cinerea (B. cinerea) and Colletotrichum gloeosporioides (C. gloeosporioides) were isolated from the decaying strawberry tissue. The antifungal properties of Monarda didyma essential oil (MEO) and its nanoemulsion were confirmed, demonstrating complete inhibition of the pathogens at concentrations of 0.45 μL/mL (0.37 mg/mL) and 10 μL/mL, respectively. Thymol, a primary component of MEO, was determined as an antimicrobial agent with IC50 values of 34.51 (B. cinerea) and 53.40 (C. gloeosporioides) μg/mL. Hippophae rhamnoides oil (HEO) was confirmed as a potent antioxidant, leading to the development of a thymol-HEO-chitosan film designed to act as an antistaling agent. The disease index and weight loss rate can be reduced by 90 and 60%, respectively, with nutrients also being well-preserved, offering an innovative approach to preservative development. Studies on the antifungal mechanism revealed that thymol could bind to FKS1 to disrupt the cell wall, causing the collapse of mitochondrial membrane potential and a burst of reactive oxygen species.

Loss of Opi3 causes a lipid imbalance that influences the virulence traits of Cryptococcus neoformans but not cryptococcosis

The basidiomycete fungus Cryptococcus neoformans is a useful model for investigating mechanisms of fungal pathogenesis in mammalian hosts. This pathogen is the causative agent of cryptococcal meningitis in immunocompromised patients and is in the critical priority group of the World Health Organization fungal priority pathogens list. In this study, we employed a mutant lacking the OPI3 gene encoding a methylene-fatty-acyl-phospholipid synthase to characterize the role of phosphatidylcholine (PC) and lipid homeostasis in the virulence of C. neoformans. We first confirmed that OPI3 was required for growth in nutrient limiting conditions, a phenotype that could be rescued with exogenous choline and PC. Additionally, we established that loss of Opi3 and the lack of PC lead to an accumulation of neutral lipids in lipid droplets and alterations in major lipid classes. The growth defect of the opi3Δ mutant was also rescued by sorbitol and polyethylene glycol (PEG), a result consistent with protection of ER function from the stress caused by lipid imbalance. We then examined the impact of Opi3 on virulence and found that the dependence of PC synthesis on Opi3 caused reduced capsule size and this was accompanied by an increase in shed capsule polysaccharide and changes in cell wall composition. Further tests of virulence demonstrated that survival in alveolar macrophages and the ability to cause disease in mice were not impacted by loss of Opi3 despite the choline auxotrophy of the mutant in vitro. Overall, this work establishes the contribution of lipid balance to virulence factor elaboration by C. neoformans and suggests that host choline is sufficient to support proliferation during disease.