Differentiation of S. chartarum (Ehrenb.) S. Hughes Chemotypes A and S via FT-IR Spectroscopy

Abstract

Stachybotrys (S.) chartarum is a cellulolytic mould with the ability to produce highly cytotoxic macrocyclic trichothecenes. Two chemotypes are defined according to their ability to produce either atranones or satratoxins. S. chartarum has been well known as the causative agent of the lethal disease stachybotryotoxicosis in horses. Further investigations revealed that this disease is strictly correlated with the presence of macrocyclic trichothecenes. Furthermore, their occurrence in water-damaged buildings has been linked to adverse health effects such as the sick building syndrome. As the chemotypes cannot be characterized via phenotypic criteria, different methods such as PCR, MALDI–TOF MS, LC–MS/MS, thin-layer chromatography and cytotoxicity assays have been used so far. Fourier-transform-infrared spectroscopy (FT-IR) is commonly used for the differentiation of bacteria and yeasts, but this technique is also applicable to filamentous fungi. Hence, this study aimed at evaluating to which extent a reliable differentiation of S. chartarum chemotypes A and S is possible. Besides, another objective was to verify if the recently introduced third genotype of S. chartarum can be identified. Therefore, 28 strains including the two chemotypes and the third genotype H were cultivated on malt extract agar (MEA) and potato dextrose agar in three biological replicates. Each sample was applied to FT-IR measurements on day 7, 14 and 21 of cultivation. In this study, we achieved a distinction of the chemotypes A and S via FT-IR spectroscopy after incubation for 7 days on MEA. In terms of genotype differentiation, the PCR detecting satratoxin- and atranone-gene clusters remained the only applicable method.

Symbiotic Husbandry of Chickens and Pigs Does Not Increase Pathogen Transmission Risk

“…By using protein spectrum analysis, the change of an individual strain and the formation of strain clusters can be recognized; thus, their spectra obtained by MALDI-TOF MS and from FT-IR proceeded to similarity analysis and the data was statistically evaluated. The mass spectrometry analysis was applied in this study, since previous studies have shown it to be highly reliable in terms of discriminatory power and the identification accuracy of microorganisms [33,[55][56][57]. Additionally, it requires less material and cost and is rather easy to be conducted with a high number of samples.…”

“…For cell masses grown for shorter/longer periods or in other nutrient solutions, the FT-IR spectra sometimes differ considerably. Therefore, reproducible and meaningful information can only be expected from cell masses obtained under standardized conditions [32,33]. To ensure these standardized conditions during FT-IR measurement, all E. coli strains were cultured on the same medium, incubated at the same room temperature for exactly 24 h. The restrained growth of Campylobacter spp.…”

Semisynthetic Approach toward Biologically Active Derivatives of Phenylspirodrimanes from S. chartarum

“…chartarum, which are characterized and distinguished by the production of certain secondary metabolites. While the group of macrocyclic trichothecenes (MCTs, e.g., satratoxins) are only found in strains of chemotype S, atranones are only produced by strains of chemotype A. , Phenylspirodrimanes (PSDs) are produced by both chemotypes of S. chartarum and account for the most abundant group of metabolites produced by all known Stachybotrys species. − …”

“…While the group of macrocyclic trichothecenes (MCTs, e.g., satratoxins) are only found in strains of chemotype S, atranones are only produced by strains of chemotype A. 5,6 Phenylspirodrimanes (PSDs) are produced by both chemotypes of S. chartarum and account for the most abundant group of metabolites produced by all known Stachybotrys species. 7−9 Phenylspirodrimanes (e.g., 1−3) are triprenyl phenols whose biosynthetic precursor LL-Z1272β (4, also known as ilicicolin B) is a well-known key intermediate in the biosynthesis of several meroterpenoid structures.…”

In Vitro Metabolism of Phenylspirodrimanes Derived from the Indoor Fungus Stachybotrys

“…The previ ously mentioned mycotoxins are a diverse group of compounds that can cause inflamma tion and nephrotoxic, hepatotoxic, and genotoxic effects in mammals [12]. Especially, th highly toxic macrocyclic trichothecenes (MCTs), which represent one of three main com pound classes produced by Stachybotrys, are a suspected cause of potential disease [13,14]. Among the MCTs, satratoxins are often produced by Stachybotrys at the highes concentrations [15,16].…”