Over the past 20 years, exposure to mycotoxin producing mold has been recognized as a significant health risk. Scientific literature has demonstrated mycotoxins as possible causes of human disease in water-damaged buildings (WDB). This study was conducted to determine if selected mycotoxins could be identified in human urine from patients suffering from chronic fatigue syndrome (CFS). Patients (n = 112) with a prior diagnosis of CFS were evaluated for mold exposure and the presence of mycotoxins in their urine. Urine was tested for aflatoxins (AT), ochratoxin A (OTA) and macrocyclic trichothecenes (MT) using Enzyme Linked Immunosorbent Assays (ELISA). Urine specimens from 104 of 112 patients (93%) were positive for at least one mycotoxin (one in the equivocal range). Almost 30% of the cases had more than one mycotoxin present. OTA was the most prevalent mycotoxin detected (83%) with MT as the next most common (44%). Exposure histories indicated current and/or past exposure to WDB in over 90% of cases. Environmental testing was performed in the WDB from a subset of these patients. This testing revealed the presence of potentially mycotoxin producing mold species and mycotoxins in the environment of the WDB. Prior testing in a healthy control population with no history of exposure to a WDB or moldy environment (n = 55) by the same laboratory, utilizing the same methods, revealed no positive cases at the limits of detection.
Semi-synthetic derivatives of the tricyclic diterpene antibiotic pleuromutilin from the basidiomycete Clitopilus passeckerianus are important in combatting bacterial infections in human and veterinary medicine. These compounds belong to the only new class of antibiotics for human applications, with novel mode of action and lack of cross-resistance, representing a class with great potential. Basidiomycete fungi, being dikaryotic, are not generally amenable to strain improvement. We report identification of the seven-gene pleuromutilin gene cluster and verify that using various targeted approaches aimed at increasing antibiotic production in C. passeckerianus, no improvement in yield was achieved. The seven-gene pleuromutilin cluster was reconstructed within Aspergillus oryzae giving production of pleuromutilin in an ascomycete, with a significant increase (2106%) in production. This is the first gene cluster from a basidiomycete to be successfully expressed in an ascomycete, and paves the way for the exploitation of a metabolically rich but traditionally overlooked group of fungi.
Red rice is a fermented product of Monascus spp. It is widely consumed by Malaysian Chinese who believe in its pharmacological properties. The traditional method of red rice preparation disregards safety regulation and renders red rice susceptible to fungal infestation and mycotoxin contamination. A preliminary study was undertaken aiming to determine the occurrence of mycotoxigenic fungi and mycotoxins contamination on red rice at consumer level in Selangor, Malaysia. Fifty red rice samples were obtained and subjected to fungal isolation, enumeration, and identification. Citrinin, aflatoxin, and ochratoxin-A were quantitated by ELISA based on the presence of predominant causal fungi. Fungal loads of 1.4 × 10(4) to 2.1 × 10(6) CFU/g exceeded Malaysian limits. Monascus spp. as starter fungi were present in 50 samples (100 %), followed by Penicillium chrysogenum (62 %), Aspergillus niger (54 %), and Aspergillus flavus (44 %). Citrinin was present in 100 % samples (0.23-20.65 mg/kg), aflatoxin in 92 % samples (0.61-77.33 μg/kg) and Ochratoxin-A in 100 % samples (0.23-2.48 μg/kg); 100 % citrinin and 76.09 % aflatoxin exceeded Malaysian limits. The presence of mycotoxigenic fungi served as an indicator of mycotoxins contamination and might imply improper production, handling, transportation, and storage of red rice. Further confirmatory analysis (e.g., HPLC) is required to verify the mycotoxins level in red rice samples and to validate the safety status of red rice.
Many fungi can develop on building material in indoor environments if moisture is high enough. Among species that are frequently observed, some are known to be potent mycotoxin producers. This presence of toxinogenic fungi in indoor environments raises the question of the possible exposure of occupants to these toxic compounds by inhalation after aerosolization.This study investigated the mycotoxin production by Penicillium brevicompactum, Aspergillus versicolor and Stachybotrys chartarum during their growth on wallpaper and the possible subsequent aerosolization of produced mycotoxins from contaminated substrates.We demonstrated that mycophenolic acid, sterigmatocystin and macrocyclic trichothecenes (sum of 4 major compounds) could be produced at levels of 1.8, 112.1 and 27.8 mg/m(2), respectively on wallpaper. Moreover, part of the produced toxins could be aerosolized from substrate. The propensity to aerosolization differed according to the fungal species. Thus, particles were aerosolized from wallpaper contaminated with P. brevicompactum when air velocity of just 0.3 m/s was applied, where S. chartarum required air velocity of 5.9 m/s. A versicolor was intermediate since aerosolization occurred under air velocity of 2 m/s.Quantification of the toxic content revealed that toxic load was mostly associated with particles of size equal or higher of 3 μm, which may correspond to spores. However, some macrocyclic trichothecenes (especially satratoxin H and verrucarin J) can also be found on smaller particles that can penetrate deeply in the respiratory tract upon inhalation. These elements are important for risk assessment related to mouldy environments.IMPORTANCE The possible colonisation of building material by toxinogenic fungi in case of moistening raises the question of the subsequent exposure of occupants to aerosolized mycotoxins. In this study, we demonstrated that three different toxinogenic species produce mycotoxins during their development on wallpaper. These toxins can subsequently be aerosolized, at least partly, from mouldy material. This transfer to air requires air velocities that can be encountered in « real life conditions » in buildings. The most part of the aerosolized toxic load is found in particles whose size corresponds to spores or mycelium fragments. However, some toxins were also found on particles smaller than spores that are easily respirable and can deeply penetrate into human respiratory tract. All these data are important for risk assessment related to fungal contamination of indoor environments.
By use of synchrotron X-ray fluorescence and Rutherford backscattering spectrometry, we show the SU-8 soft lithographic process contaminates PDMS. Residues of the antimony containing photoinitiator are transferred from the master mold to the surface of PDMS, uncontrollably intensifying the surface potential, leading to electroosmotic flow variability in PDMS microfluidic devices.
Contamination of food industrial environments and recontamination of finished products by Chrysonilia sitophila and Hyphopichia burtonii has long been a serious problem for the bakery industries. As one of the most common ways to slow down or avoid fungal spoilage on bakery products is the use of ethanol, in the present work the effect of this substance has been assessed on growth of two of the most frequently occurring associated moulds, C. sitophila and H. burtonii, by means of tests on both synthetic media and sliced bread. Test on synthetic media: H. burtonii was less markedly affected in lag-phase duration and radial growth rates by the addition of ethanol to DG18 and the reduction of incubation temperature than C. sitophila that failed to grow at the highest concentrations of ethanol tested (2.0% and 4.0% at 15°C; 4.0% at 25°C). Test on sliced bread: ethanol proved to be effective to prevent spoilage by C. sitophila even at the lowest concentration tested (0.8%, wt/wt), while higher concentrations (2.0%, wt/wt) were needed to prevent spoilage by H. burtonii. This article is protected by copyright. All rights reserved.
- International journal of medical microbiology : IJMM
- Published almost 2 years ago
Treatment of invasive fungal infections often fails due to the limited number of therapeutic options. In this study, we have analyzed the impact of agents activating the High Osmolarity Glycerol (HOG) pathway on molds that cause infections in humans and livestock. We found that agents like fludioxonil and iprodione, have a clear anti-fungal activity against pathogenic Aspergillus, Lichtheimia, Rhizopus and Scedosporium species. Only A. terreus turned out to be resistant to fludioxonil, even though it is sensitive to iprodione and able to adapt to hyperosmotic conditions. Moreover, the A. terreus tcsC gene can fully complement an A. fumigatus ΔtcsC mutant, thereby also restoring its sensitivity to fludioxonil. The particular phenotype of A. terreus is therefore likely to be independent of its TcsC kinase. In a second part of this study, we further explored the impact of fludioxonil using A. fumigatus as a model organism. When applied in concentrations of 1-2μg/ml, fludioxonil causes an immediate growth arrest and, after longer exposure, a quantitative killing. Hyphae respond to fludioxonil by the formation of new septa and closure of nearly all septal pores. Mitosis occurs in all compartments and is accompanied by a re-localization of the NimA kinase to the cytoplasm. In the swollen compartments, the massive extension of the cell wall triggers a substantial reorganization resulting in an enhanced incorporation of chitin and, most strikingly, a massive loss of galactomannan. Hence, HOG-activating agents have dramatic cell biological consequences and may represent a valuable, future element in the armory that can be used to combat mold infections.
It has recently been demonstrated that patients who develop chronic illness after prior exposure to water damaged buildings (WDB) and mold have the presence of mycotoxins, which can be detected in the urine. We hypothesized that the mold may be harbored internally and continue to release and/or produce mycotoxins which contribute to ongoing chronic illness. The sinuses are the most likely candidate as a site for the internal mold and mycotoxin production. In this paper, we review the literature supporting this concept.
The rise in antibiotic resistance is a major threat for human health. Basidiomycete fungi represent an untapped source of underexploited antimicrobials, with pleuromutilin-a diterpene produced by Clitopilus passeckerianus-being the only antibiotic from these fungi leading to commercial derivatives. Here we report genetic characterisation of the steps involved in pleuromutilin biosynthesis, through rational heterologous expression in Aspergillus oryzae coupled with isolation and detailed structural elucidation of the pathway intermediates by spectroscopic methods and comparison with synthetic standards. A. oryzae was further established as a platform for bio-conversion of chemically modified analogues of pleuromutilin intermediates, and was employed to generate a semi-synthetic pleuromutilin derivative with enhanced antibiotic activity. These studies pave the way for future characterisation of biosynthetic pathways of other basidiomycete natural products in ascomycete heterologous hosts, and open up new possibilities of further chemical modification for the growing class of potent pleuromutilin antibiotics.
Molds can cause respiratory symptoms and asthma. We sought to use isolated peripheral blood mononuclear cells (PBMCs) to understand changes in cytokine and chemokine levels in response to mold and mycotoxin exposures and to link these levels with respiratory symptoms in humans. We did this by utilizing an ex vivo assay approach to differentiate mold-exposed patients and unexposed controls. While circulating plasma chemokine and cytokine levels from these two groups might be similar, we hypothesized that by challenging their isolated white blood cells with mold or mold extracts, we would see a differential chemokine and cytokine release.