Fungal Glucan Research Articles

The Glucanase Enzyme Activity from Rhizospheric Streptomyces spp. in Inhibiting Growth and Damaging the Cell Walls of the Mycelium of Fusarium oxysporum

Fusarium oxysporum, a phytopathogenic fungus responsible for fusarium wilt in more than 120 plant species, is primarily managed using synthetic fungicides, which pose environmental hazards. Therefore, alternative biological control methods are urgently needed. Actinomycetes isolated from maize rhizosphere, which produce β-1.3-glucanase enzymes that degrade fungal cell wall glucans, offer promising potential as biocontrol agents. This study aimed to evaluate glucanase activity, identify genes of actinomycetes, and assess their antifungal activity against F. oxysporum. Actinomycetes demonstrating glucanase production, Streptomyces sp. ARJ 22, Streptomyces tendae ARJ 42, Streptomyces sp. ARJ 44, and Streptomyces sp. ARJ 81, were selected. Streptomyces isolates exhibited activity values ranging from 10.38 to 24.08 U/mg of protein. The presence of the bglS gene, encoding endo-β-1.3-glucanase from glycoside hydrolase family 16, supports the production of glucanase. The amino acid sequence was constructed to 3D structural model. This model exhibited high similarity to endo-β-1.3-glucanase from Nocardiopsis sp. F96. In vitro assays demonstrated that all isolates inhibited hyphal growth of F. oxysporum. Direct inhibition assays showed an average inhibition of 26.18%, whereas the filtrate culture method showed 29.38% inhibition. Enzymes from Streptomyces sp. ARJ 44 was partially purified using acetone, resulting in a specific activity of 46.34 U/mg of protein and a purity increase of up to 1.92-fold. The purified enzyme inhibited the growth of F. oxysporum mycelia by 35.80%. This inhibition was confirmed by observing damage to F. oxysporum hyphae using scanning electron microscopy. The study concluded that the four Streptomyces sp. strains producing β-1.3-glucanase enzymes have potential as biocontrol agents against F. oxysporum.

Trained immunity inducers in cancer immunotherapy.

While most of the cancer immunotherapy strategies engage adaptive immunity, especially tumor-associated T cells, the small fraction of responding patients and types of cancers amenable, and the possibility of severe adverse effects limit its usage. More effective and general interventions are urgently needed. Recently, a de facto innate immune memory, termed 'trained immunity', has become a new research focal point, and promises to be a powerful tool for achieving long-term therapeutic benefits against cancers. Trained immunity-inducing agents such as BCG and fungal glucan have been shown to be able to avert the suppressive tumor microenvironment (TME), enhance T cell responses, and eventually lead to tumor regression. Here, we review the current understating of trained immunity induction and highlight the critical roles of emergency granulopoiesis, interferon γ and tissue-specific induction. Preclinical and clinical studies that have exploited trained immunity inducers for cancer immunotherapy are summarized, and repurposed trained immunity inducers from other fields are proposed. We also outline the challenges and opportunities for trained immunity in future cancer immunotherapies. We envisage that more effective cancer vaccines will combine the induction of trained immunity with T cell therapies.

Glucans and heteroglycans of fungi and their possibilities in immunotherapy of malignant neoplasms

The present review is devoted to the oncostatic properties of glucans and heteroglycans produced by higher fungi. These are the most pharmacologically promising substances, since they are produced in large quantities both by artificially grown mycelium and fruiting bodies, do not require complex purification methods, are devoid of toxicity, and, having a complex (immune-mediated and direct) effect on tumors, do not require any complex fractionation procedures. The diversity of β-glucans produced by fungi is shown, the main types of these macromolecules are considered (according to the structural features of the macromolecule, the linear and branched forms of β-glucans are distinguished, first of all). Heteroglycans, a more diverse but less studied group of fungal compounds, have also been characterized. The effects of fungal polysaccharides and heteroglycans on immune and cancer cells described in the literature are considered. The long and branched chains of these biopolymers, as well as peptides and lipids covalently bound to them, have fragments that are complementary to the binding sites of the surface receptors of the animal cell and thus act as their agonists or antagonists. They are recognized by the receptors of antigen-representing cells of the immune system as pathogen-associated molecular patterns, what leads to the activation of the cytotoxic component of the immune system; to reduce their tolerogenic and immunosuppressive signaling. Prospects for further study of fungal glucans and heteroglycans are outlined.

Indoor air quality in remote first nations communities in Ontario, Canada.

A recent study of the health of Indigenous children in four First Nations Communities in remote northwestern Ontario found that 21% of children had been admitted to hospital for respiratory infections before age 2 years. Here we report a detailed analysis of the housing conditions in these communities. We employed a variety of statistical methods, including linear regression, mixed models, and logistic regression, to assess the correlations between housing conditions and loadings of biocontaminants (dust mite allergens, fungal glucan, and endotoxin) and indoor concentrations of PM2.5, CO2, benzene, and formaldehyde. The houses (n = 101) were crowded with an average of approximately 7 people. Approximately 27% of the homes had sustained CO2 concentrations above 1500 ppm. Most homes had more than one smoker. Commercial tobacco smoking and the use of non-electric heating (e.g., wood, oil) were associated with increased fine particle concentrations. Over 90% of the homes lacked working Heat Recovery Ventilators (HRVs), which was associated with increased fine particle concentrations and higher CO2. Of the 101 homes, 12 had mold damage sufficient to increase the relative risk of respiratory disease. This resulted from roof leaks, through walls or around the windows due to construction defects or lack of maintenance. A similar percentage had mold resulting from condensation on windows. Endotoxin loadings were much higher than any previous study in Canada. This work provides evidence for the need for more effort to repair existing houses and to ensure the HRVs are properly installed and maintained.

A glycan receptor kinase facilitates intracellular accommodation of arbuscular mycorrhiza and symbiotic rhizobia in the legume Lotus japonicus.

Receptors that distinguish the multitude of microbes surrounding plants in the environment enable dynamic responses to the biotic and abiotic conditions encountered. In this study, we identify and characterise a glycan receptor kinase, EPR3a, closely related to the exopolysaccharide receptor EPR3. Epr3a is up-regulated in roots colonised by arbuscular mycorrhizal (AM) fungi and is able to bind glucans with a branching pattern characteristic of surface-exposed fungal glucans. Expression studies with cellular resolution show localised activation of the Epr3a promoter in cortical root cells containing arbuscules. Fungal infection and intracellular arbuscule formation are reduced in epr3a mutants. In vitro, the EPR3a ectodomain binds cell wall glucans in affinity gel electrophoresis assays. In microscale thermophoresis (MST) assays, rhizobial exopolysaccharide binding is detected with affinities comparable to those observed for EPR3, and both EPR3a and EPR3 bind a well-defined β-1,3/β-1,6 decasaccharide derived from exopolysaccharides of endophytic and pathogenic fungi. Both EPR3a and EPR3 function in the intracellular accommodation of microbes. However, contrasting expression patterns and divergent ligand affinities result in distinct functions in AM colonisation and rhizobial infection in Lotus japonicus. The presence of Epr3a and Epr3 genes in both eudicot and monocot plant genomes suggest a conserved function of these receptor kinases in glycan perception.

Polymycovirus Infection Sensitizes Aspergillus fumigatus for Antifungal Effects of Nikkomycin Z.

Infection with Aspergillus fumigatus polymycovirus 1 (AfuPmV-1) weakens resistance of Aspergillus fumigatus common reference strain Af293 biofilms in intermicrobial competition with Pseudomonas aeruginosa. We compared the sensitivity of two infected and one virus-free Af293 strains to antifungal drugs. All three were comparably sensitive to drugs affecting fungal membranes (voriconazole, amphotericin) or cell wall glucan synthesis (micafungin, caspofungin). In contrast, forming biofilms of virus-free Af293 were much more resistant than AfuPmV-1-infected Af293 to nikkomycin Z (NikZ), a drug inhibiting chitin synthase. The IC50 for NikZ on biofilms was between 3.8 and 7.5 µg/mL for virus-free Af293 and 0.94-1.88 µg/mL for infected strains. The IC50 for the virus-free A. fumigatus strain 10AF was ~2 µg/mL in most experiments. NikZ also modestly affected the planktonic growth of infected Af293 more than the virus-free strain (MIC 50%, 2 and 4 µg/mL, respectively). Virus-free Af293 biofilm showed increased metabolism, and fungus growing as biofilm or planktonically showed increased growth compared to infected; these differences do not explain the resistance of the virus-free fungus to NikZ. In summary, AfuPmV-1 infection sensitized A. fumigatus to NikZ, but did not affect response to drugs commonly used against A. fumigatus infection. Virus infection had a greater effect on NikZ inhibition of biofilm than planktonic growth.

Professor Solomon P. Wasser and Medicinal Mushroom Science, with Special Attention to the Problems of Mycotherapy in Oncology.

This article is dedicated to the 75th anniversary of Solomon P. Wasser and discusses the challenges within the research direction he founded with Professors T. Mizuno, S.T. Chang, and other colleagues, known as medicinal mushroom science. This research organically grows out of taxonomic studies, since understanding of the classification system leads to greater ability to make forecasts and predictions in the practical field as well as to increase knowledge of close relationships between organisms, allowing greater eeconomic organization within the search and screening for new practically significant organisms. Through the efforts of Professors Wasser, Mizuno, and Chang, the International Journal of Medicinal Mushrooms (IJMM) was created, combining the efforts of physicians using mushroom raw materials as an auxiliary tool and specialists in fungal biotechnology. In this work, the basic prerequisites for cancer mycotherapy are described, based on data on the mechanism of action of fungal metabolites on cancer targets. A large section of this report is devoted to a review of evidence-based medicine tools and an overview of their use among teams of Chinese researchers. It has been shown that the main recipients of mycotherapy, as well as other types of immunotherapies, are patients with stage 3 cancer who have undergone surgery to remove the primary tumor node and are undergoing chemotherapy; for these patients, their immune status must be increased, and the immune system requires a periodic rebooting. In this respect, Dectin stimulation using fungal glucans is comparable to cytokine therapy and can be characterized as an "endogenous cytokine therapy." The results of the combined treatment at this stage are to be quantified using evidence-based medicine tools, for which we recommend including the consumption of mushroom extracts in the patient questionnaire. This article also discusses challenges in the pharmacokinetics of β-glucans and triterpenoids.

A uridine diphosphate-glycosyltransferase GFUGT88A1 derived from edible mushroom Grifola frondosa extends oligosaccharide chains

Fungal glucans play a key role to provide energy, support cell structure, and present biological functions. However, the biosynthetic machineries of fungal glucan chains remain to be elucidated. Hence, we aimed to elucidate the biochemical and catalytic characteristics of a novel glucan synthesis-associated enzyme uridine diphosphate (UDP)-glycosyltransferase GFUGT88A1 derived from Grifola frondosa and predict its potential catalytic mechanism. The purified recombinant GFUGT88A1 had a molecular weight of 51.7 kDa with an optimum temperature of 37 °C and pH of 7.0. GFUGT88A1 showed preference for oligosaccharides with relatively higher polymerization degrees (≥6) as acceptors to extend its chain when using UDP-glucose as a donor. Molecular modeling and docking of GFUGT88A1 with donor UDP-glucose, and acceptors laminaribiose, laminarihexaose, and laminarinonaose indicated that the predicted amino acid residues at the active sites may bind the donor/acceptor protein primarily via hydrogen bonds with various binding energy values. The present study revealed that GFUGT88A1 extended glucan chains, which provides a reference to understand the biosynthesis pathway of mushroom glucans.

Pulmonary eosinophilia may indicate onset stage of allergic bronchopulmonary aspergillosis

BackgroundAllergic bronchopulmonary aspergillosis (ABPA) and chronic eosinophilic pneumonia (CEP) both display peripheral eosinophilia as well as pulmonary infiltration, together described as pulmonary eosinophilia, and differentiation is sometimes problematic. This study therefore examined the distinctions between ABPA with and without CEP-like shadows.MethodsThis retrospective cohort study from a single center included 25 outpatients (median age, 65 years) with ABPA diagnosed between April 2015 and March 2019, using criteria proposed by the International Society of Human and Animal Mycology (ISHAM), which focuses on positive specific IgE for Aspergillus fumigatus. Patients were assigned to either the eosinophilic pneumonia (EP) group or Non-EP group, defined according to findings on high-resolution computed tomography (HRCT). The EP group included patients with HRCT findings compatible with CEP; i.e., the presence of peripheral consolidation (p-consolidation) or ground-glass opacities (GGO), with no evidence of high-attenuation mucus. The Non-EP group comprised the remaining patients, who showed classical findings of ABPA such as mucoid impaction. Differences between the groups were analyzed.ResultsBaseline characteristics, frequency of a history of CEP (EP, 50% vs. Non-EP, 26%) and tentative diagnosis of CEP before diagnosis of ABPA (67% vs. 16%) did not differ significantly between groups. Although elevated absolute eosinophil count and Aspergillus-specific immunoglobulin E titers did not differ significantly between groups, the Non-EP group showed a strong positive correlation between these values (R = 0.7878, p = 0.0003). The Non-EP group displayed significantly higher levels of the fungal marker beta-D glucan (median, 11.7 pg/ml; interquartile range, 6.7–18.4 pg/ml) than the EP group (median, 6.6 pg/ml; interquartile range, 5.2–9.3 pg/ml). Both groups exhibited frequent recurrence of shadows on X-rays but no cases in the EP group had progressed to the Non-EP group at the time of relapse.ConclusionsThe ABPA subgroup with imaging findings resembling CEP experienced frequent recurrences, as in typical ABPA. In pulmonary eosinophilia, even if there are no shadows indicating apparent mucous change, the Aspergillus-specific immunoglobulin E level is important in obtaining an accurate diagnosis and in the selection of appropriate therapies for this type of ABPA.

Deposition Rates of Asthma Triggers on Conventional and Enclosed Window Treatments

Environmental interventions are an important element of managing allergies and asthma. Health professionals often recommend that draperies be replaced with window blinds however no data exist on accumulation of inhalant allergens or inflammatory bioaerosols on window treatments. Installing blinds that accumulate less dust may reduce breathing zone exposures when blinds are adjusted if hazardous amounts of bioaerosols are deposited. We sought to determine the rate of accumulation of dust, allergens, bacterial endotoxin and fungal glucan on window blinds of two distinct types mounted on the two types of windows most commonly installed in U.S. homes. The blinds tested were conventional horizontal slat blinds hanging on the inside of the window (roomside blinds) and similar blinds placed between the exterior window glass and an extra pane of glass on the interior side (between-glass blinds). The study was conducted in six households as a paired, repeated measures study. Households were identified for participation, having met the study criteria of children and cats living inside a carpeted home. Standard window blinds accumulated cat allergen, endotoxin and fungal glucan at rates of 5940ng/m², 1910EU/m², and 11,360ng/m² per month. Between-glass blinds reduced the loading of asthma triggers by 25- to 185-fold. Comparison with clinical thresholds associated with asthma morbidity indicates that room-side blinds accumulate potentially hazardous quantities of asthma triggers.

Immunomodulating Effects of Fungal Beta-Glucans: From Traditional Use to Medicine.

The importance of a well-functioning and balanced immune system has become more apparent in recent decades. Various elements have however not yet been uncovered as shown, for example, in the uncertainty on immune system responses to COVID-19. Fungal beta-glucans are bioactive molecules with immunomodulating properties. Insights into the effects and function of beta-glucans, which have been used in traditional Chinese medicine for centuries, advances with the help of modern immunological and biotechnological methods. However, it is still unclear into which area beta-glucans fit best: supplements or medicine? This review has highlighted the potential application of fungal beta-glucans in nutrition and medicine, reviewing their formulation, efficacy, safety profile, and immunomodulating effects. The current status of dietary fungal glucans with respect to the European scientific requirements for health claims related to the immune system and defense against pathogens has been reviewed. Comparing the evidence base of the putative health effects of fungal beta-glucan supplements with the published guidance documents by EFSA on substantiating immune stimulation and pathogen defense by food products shows that fungal beta-glucans could play a role in supporting and maintaining health and, thus, can be seen as a good health-promoting substance from food, which could mean that this effect may also be claimed if approved. In addition to these developments related to food uses of beta-glucan-containing supplements, beta-glucans could also hold a novel position in Western medicine as the concept of trained immunity is relatively new and has not been investigated to a large extent. These innovative concepts, together with the emerging success of modern immunological and biotechnological methods, suggest that fungal glucans may play a promising role in both perspectives, and that there are possibilities for traditional medicine to provide an immunological application in both medicine and nutrition.

Pretreatment with Antibiotics Impairs Th17-Mediated Antifungal Immunity in Newborn Rats.

Clinical studies have confirmed that the use of antibiotics, especially carbapenems, is a high-risk factor for fungal infection in preterm infants. However, it is not entirely clear whether the increased risk for fungal infection is due to the immune differences in preterm infants or antibiotic usage. We found that after newborn rats received antibiotics, they exhibited significantly impaired anti-Candida albicans immunity in comparison with those without treatment, as shown by significantly increased levels of fungal glucan in the peripheral blood, multiple caseous fungal infections in the abdominal cavity, intestinal congestion, ischemia, and a decrease in the number of intestinal villi. Mechanistically, pretreatment with antibiotics diminished antifungal innate immunity by TLR2 and inhibited IL-17A release and neutrophil recruitment, leading to increased susceptibility to fungi. In summary, we demonstrate that antibiotic usage impairs antifungal immunity in neonates and suggest that antifungal prophylaxis may be required after antibiotic treatment in high-risk preterm babies.

Threonine Phosphorylation of IκBζ Mediates Inhibition of Selective Proinflammatory Target Genes

Transcription factors of the NF-κB family play a crucial role for immune responses by activating the expression of chemokines, cytokines, and antimicrobial peptides involved in pathogen clearance. IκBζ, an atypical nuclear IκB protein and selective coactivator of particular NF-κB target genes, has recently been identified as an essential regulator for skin immunity. This study discovered that IκBζ is strongly induced in keratinocytes that sense the fungal glucan zymosan A. Additionally, IκBζ is essential for the optimal expression of proinflammatory genes, such as IL6, CXCL5, IL1B, or S100A9. Moreover, this study found that IκBζ was not solely regulated on the transcriptional level but also by phosphorylation events. This study identified several IκBζ phosphorylation sites, including a conserved cluster of threonine residues located in the N-terminus of the protein, which can be phosphorylated by MAPKs. Surprisingly, IκBζ phosphorylation at this threonine cluster promoted the recruitment of histone deacetylase 1 to specific target gene promoters and, thus, negatively controlled transcription. Taken together, this study proposes a model of how an antifungal response translates to the expression of proinflammatory cytokines and highlights an additional layer of complexity in the regulation of the NF-κB responses in keratinocytes.

Candida albicans enhances meropenem tolerance of Pseudomonas aeruginosa in a dual-species biofilm.

Background Pseudomonas aeruginosa is an opportunistic bacterium that infects the airways of cystic fibrosis patients, surfaces of surgical and burn wounds, and indwelling medical devices. Patients are prone to secondary fungal infections, with Candida albicans being commonly co-isolated with P. aeruginosa. Both P. aeruginosa and C. albicans are able to form extensive biofilms on the surfaces of mucosa and medical devices.ObjectivesTo determine whether the presence of C. albicans enhances antibiotic tolerance of P. aeruginosa in a dual-species biofilm.MethodsSingle- and dual-species biofilms were established in microtitre plates and the survival of each species was measured following treatment with clinically relevant antibiotics. Scanning electron microscopy and confocal microscopy were used to visualize biofilm structure.Results C. albicans enhances P. aeruginosa biofilm tolerance to meropenem at the clinically relevant concentration of 5 mg/L. This effect is specific to biofilm cultures and is dependent upon C. albicans extracellular matrix polysaccharides, mannan and glucan, with C. albicans cells deficient in glycosylation structures not enhancing P. aeruginosa tolerance to meropenem.ConclusionsWe propose that fungal mannan and glucan secreted into the extracellular matrix of P. aeruginosa/C. albicans dual-species biofilms play a central role in enhancing P. aeruginosa tolerance to meropenem, which has direct implications for the treatment of coinfected patients.

The influence of product acidity and beta-glucans isolated from various sources on the mineral composition and the mechanical and microstructural properties of the femur in growing Wistar rats

The aim of this study was to determine the influence of a standard diet enriched with yoghurt (acidified milk) and milk gel (non-acidified milk) and three structurally different beta-glucans (isolated from oats, bacteria and fungi) on the mineral composition and the mechanical and microstructural properties of the femur in growing rats.Feed intake and the feed conversion ratio were influenced by product acidity and the applied beta-glucan. A significant increase in bacterial counts was noted only in the animals fed fungal glucan. Dietary supplementation with beta-glucans significantly decreased the acidity of intestinal contents. The calcium content of bones was determined mainly by the acidity of milk gel than by the type of beta-glucans. The Ca:P ratio in the femurs of rats fed yoghurt was higher than in the animals fed milk gel. Higher failure load was noted in rats fed yoghurt with beta-glucans. Trabecular thickness was highest in rats fed yoghurt with oat beta-glucan and lowest in rats fed milk gel with fungal beta-glucan.

Immunoregulatory Activity of the Natural Product Laminarin Varies Widely as a Result of Its Physical Properties.

Ligation of Dectin-1 by fungal glucans elicits a Th17 response that is necessary for clearing many fungal pathogens. Laminarin is a (1→3, 1→6)-β-glucan that is widely reported to be a Dectin-1 antagonist, however, there are reports that laminarin is also a Dectin-1 agonist. To address this controversy, we assessed the physical properties, structure, purity, Dectin-1 binding, and biological activity of five different laminarin preparations from three different commercial sources. The proton nuclear magnetic resonance analysis indicated that all of the preparations contained laminarin although their molecular mass varied considerably (4400-34,400 Da). Two of the laminarins contained substantial quantities of very low m.w. compounds, some of which were not laminarin. These low m.w. moieties could be significantly reduced by extensive dialysis. All of the laminarin preparations were bound by recombinant human Dectin-1 and mouse Dectin-1, but the affinity varied considerably, and binding affinity did not correlate with Dectin-1 agonism, antagonism, or potency. In both human and mouse cells, two laminarins were Dectin-1 antagonists and two were Dectin-1 agonists. The remaining laminarin was a Dectin-1 antagonist, but when the low m.w. moieties were removed, it became an agonist. We were able to identify a laminarin that is a Dectin-1 agonist and a laminarin that is Dectin-1 antagonist, both of which are relatively pure preparations. These laminarins may be useful in elucidating the structure and activity relationships of glucan/Dectin-1 interactions. Our data demonstrate that laminarin can be either a Dectin-1 antagonist or agonist, depending on the physicochemical properties, purity, and structure of the laminarin preparation employed.

In vitro immunostimulatory potential of fungal β-glucans in pacific red snapper (Lutjanus peru) cells

This study attempts to describe the immunostimulatory effects of three fungal glucans on innate immunity responses in an in vitro assays using Pacific red snapper leukocytes. First, the yield glucans obtained was higher in Aspergillus niger, follow by Aspergillus ochraceus and Alternaria botrytis (40, 20 and 10%, respectively). Structural characterization of these fungal glucans by proton nuclear magnetic resonance (NMR) indicated structures containing (1–6)-branched (1–3)-β-D-glucan. The immunostimulatory activity of fungal glucans were assessed in head-kidney leukocytes at 24 h using colorimetric assays and molecular gene expression. In addition, the response against bacterial infection using Aeromonas hydrophila was evaluated by flow cytometry with annexin V/propidium iodide. Leukocytes responded positively to fungal glucans where the viability was higher than 80%. Interestingly, A. niger β-glucans enhanced the phagocytic ability and capacity in head-kidney leukocytes. Immunological assays reveled an increased in nitric oxide production, myeloperoxidase, superoxide dismutase and catalase activities, in fish stimulated with A. niger β-glucans. Induction of cytokines (IL-1β, TNF-α, IL-6, IL-8 and IL-12) were more pronounced in A. niger β-glucans leukocytes stimulated compared to other group. Finally, flow cytometry assay showed that A. botrytis and A. niger β-glucans were able to inhibit apoptosis caused by Aeromonas hydrophila in the Pacific red snapper leukocytes indicating an immunostimulant potent response by fungi derived-glucans. These results strongly support the idea that fungal β-glucans can stimulate the immune mechanism in head-kidney leukocytes and that Aspergillus niger β-glucan possess immunostimulatory properties cell increasing viability, and reducing necrotic cell death caused by Aeromonas hydrophila.

Inflammation-associated gene expression in RAW 264.7 macrophages induced by toxins from fungi common on damp building materials

Most fungi that grow on damp building materials produce low molecular weight compounds, some of which are known to be toxic. In this study, we tested the hypothesis that exposure to some metabolites of fungi common on damp building materials would result in time-, dose-, and compound-specific responses in the production of various chemokines by RAW 264.7 cells. Cell cultures were exposed to a 10−7M or 10−8M metabolite dose for 2, 4, 8 or 24h. Metabolite concentrations used were based on those that might be expected in alveolar macrophages due to inhalation exposure from living or working in a damp building. Compared to controls, exposure provoked significant time-, dose- and compound-specific responses manifest as differentially elevated secretion of three of nine cytokines tested in culture supernatant of treated cells. The greatest number of cytokines produced in response to the metabolites tested were in andrastin A-treated cells (GM-CSF, TGFβ1, Tnf-α) followed by koninginin A (TGFβ1 and Tnf-α) and phomenone (GM-CSF, TGFβ1). Chaetoglobosin A, chaetomugilin D and walleminone exposures each resulted in significant time-specific production of Tnf-α only. This investigation adds to a body of evidence supporting the role of low molecular weight compounds from damp building materials as pathogen associated molecular patterns (PAMPs). Along with fungal glucan and chitin, these compounds contribute to the non-allergy based respiratory outcomes for people living and working in damp buildings.

Metabolites of Trichoderma species isolated from damp building materials.

Buildings that have been flooded often have high concentrations of Trichoderma spores in the air while drying. Inhaled spores and spore and mycelial fragments contain large amounts of fungal glucan and natural products that contribute to the symptoms associated with indoor mould exposures. In this study, we considered both small molecules and peptaibol profiles of T. atroviride, T. koningiopsis, T. citrinoviride, and T. harzianum strains obtained from damp buildings in eastern Canada. Twenty-residue peptaibols and sorbicillin-derived metabolites (1-6) including a new structure, (R)-vertinolide (1), were characterized from T. citrinoviride. Trichoderma koningiopsis produced several koninginins (7-10), trikoningin KA V, and the 11-residue lipopeptaibols trikoningin KB I and trikoningin KB II. Trichoderma atroviride biosynthesized a mixture of 19-residue trichorzianine-like peptaibols, whereas T. harzianum produced 18-residue trichokindin-like peptaibols and the 11-residue harzianin HB I that was subsequently identified from the studied T. citrinoviride strain. Two α-pyrones, 6-pentyl-pyran-2-one (11) and an oxidized analog (12), were produced by both T. atroviride and T. harzianum. Aside from exposure to low molecular weight natural products, inhalation of Trichoderma spores and mycelial fragments may result in exposure to membrane-disrupting peptaibols. This investigation contributes to a more comprehensive understanding of the biologically active natural products produced by fungi commonly found in damp buildings.

New developments and directions in the clinical application of the echinocandins.

The echinocandins-caspofungin, anidulafungin and micafungin-are semi-synthetic cyclic hexapeptide antimicrobial agents with modified N-linked acyl lipid side chains which anchor the compounds to the phospholipid bilayer of the fungal cell membrane, thereby inhibiting synthesis of fungal cell wall glucan. Over the last 10years, echinocandins have become the first-line antifungal treatment of candidaemia and other forms of invasive candidiasis (IC). Echinocandins are generally well tolerated, but their use is limited by their requirement for daily intravenous dosing, lack of oral formulation and limited spectrum. In critically ill patients, it is also recognised that achievement of their pharmacokinetic/pharmacodynamic targets shows large inter-individual variability. As a drug class, they are safe to use and are associated with few adverse reactions and few drug-drug interactions of significance. Recent discovery of their ability to prevent and treat Candida biofilm formation particularly in the presence of invasive medical devices and also their ability to penetrate into mucosal surfaces such as vulvovaginal candidiasis has opened up new opportunities for research into their drug delivery. New dosing intervals are being explored to allow less frequent intravenous dosing in the ambulatory setting, and a new long-acting echinocandin, CD101, is being developed for weekly and topical administration.