Identification of mycotoxins by UHPLC-QTOF MS in airborne fungi and fungi isolated from industrial paper and antique documents from the Archive of Bogotá

Microbial Assessment in A Rare Norwegian Book Collection: A One Health Approach to Cultural Heritage

Microbial contamination poses a threat to both the preservation of library and archival collections and the health of staff and users. This study investigated the microbial communities and potential health risks associated with the UNESCO-classified Norwegian Sea Trade Archive (NST Archive) collection exhibiting visible microbial colonization and staff health concerns. Dust samples from book surfaces and the storage environment were analysed using culturing methods, qPCR, Next Generation Sequencing, and mycotoxin, cytotoxicity, and azole resistance assays. Penicillium sp., Aspergillus sp., and Cladosporium sp. were the most common fungi identified, with some potentially toxic species like Stachybotrys sp., Toxicladosporium sp., and Aspergillus section Fumigati. Fungal resistance to azoles was not detected. Only one mycotoxin, sterigmatocystin, was found in a heavily contaminated book. Dust extracts from books exhibited moderate to high cytotoxicity on human lung cells, suggesting a potential respiratory risk. The collection had higher contamination levels compared to the storage environment, likely due to improved storage conditions. Even though overall low contamination levels were obtained, these might be underestimated due to the presence of salt (from cod preservation) that could have interfered with the analyses. This study underlines the importance of monitoring microbial communities and implementing proper storage measures to safeguard cultural heritage and staff well-being.

Penicillium chrysogenum, a Vintage Model with a Cutting-Edge Profile in Biotechnology

The discovery of penicillin entailed a decisive breakthrough in medicine. No other medical advance has ever had the same impact in the clinical practise. The fungus Penicillium chrysogenum (reclassified as P. rubens) has been used for industrial production of penicillin ever since the forties of the past century; industrial biotechnology developed hand in hand with it, and currently P. chrysogenum is a thoroughly studied model for secondary metabolite production and regulation. In addition to its role as penicillin producer, recent synthetic biology advances have put P. chrysogenum on the path to become a cell factory for the production of metabolites with biotechnological interest. In this review, we tell the history of P. chrysogenum, from the discovery of penicillin and the first isolation of strains with high production capacity to the most recent research advances with the fungus. We will describe how classical strain improvement programs achieved the goal of increasing production and how the development of different molecular tools allowed further improvements. The discovery of the penicillin gene cluster, the origin of the penicillin genes, the regulation of penicillin production, and a compilation of other P. chrysogenum secondary metabolites will also be covered and updated in this work.

The Potential of Fatty Acids and Their Derivatives as Antifungal Agents: A Review

Fungal contamination presents several problems: in humans, health issues arise from infections with opportunistic filamentous fungi and yeast, while in food, fungi cause spoilage and, in particular, in the case of mycotoxigenic fungi, can cause serious health issues. Several types of fatty acids and their derivatives, oxylipins, have been found to have inhibitory effect towards fungal growth and the production of mycotoxins. The use of fatty acids as antifungals could fulfil consumer’s requests of more natural and environmentally friendly compounds, while being less likely to promote fungal resistance. In addition, due to their nature, fatty acids are easily used as food additives. In this work, we review the most relevant and recent studies on the antifungal ability of fatty acids. We focused on saturated fatty acids, unsaturated fatty acids, and oxylipins, their different impact on fungal inhibition, their proposed modes of action, and their ability to impair mycotoxin production. Applications of fatty acids as antifungals and their limitations are also addressed.

Kinetics, mechanisms and toxicity of the degradation of imidaclothiz in soil and water

Hydrolysis and photolysis are important degradation pathways of pesticides while their degradation in soil is a principal metabolic pathway. These processes might generate toxic chemicals and pose threats to the environment. As a member of the controversial neonicotinoid pesticides, the environmental fate and toxicity of imidaclothiz and its potential metabolites have remained ambiguous. Laboratory experiments were conducted to study the degradation kinetics, mechanisms and toxicity of imidaclothiz in aqueous solutions (pH = 4, 7, 9 buffer solutions and ultra-pure water) and soil (black soil, red soil and fluvo-aquic soil) under different conditions (25 ℃ and 50 ℃). The results showed that imidaclothiz was fairly stable in water and soil under natural conditions. Based on the mass accuracy of the parent chemical and conserved fragment ions, ten candidate degradation products were filtered out using UHPLC-QTOF-MS and the UNIFI system. Then, two of the candidates were synthesized, analysed, and compared with standards to confirm. The microscopic mechanisms of three degradation reactions (imidaclothiz degraded to M216, M216 degraded to M217 and M216 degraded to M198) were elucidated using theoretical calculations. The toxicity data from experiments and the ECOSAR prediction showed that imidaclothiz had low toxicity to Daphnia magna and Danio rerio and had high toxicity to Apis mellifera, with 50% of the degradation products in this study exhibiting higher toxicities to aquatic organisms than the parent chemical.

Reisolation and NMR characterization of the satratoxins G and H

The exquisitely cytotoxic macrolides, satratoxins G and H, have been reisolated from a solvent extract of a rice culture inoculated with Stachybotrys chartarum to be used as high-purity reference compounds for analytical analyses. Extensive chromatographic separation realized the compounds that were fully recharacterized in two solvents by 1D- and 2D-NMR spectroscopy, revealing some discrepancies in the nuclear magnetic resonance (NMR) data as compared with the previously reported values found in the literature. Detailed spectra are provided in order to aid future identification and dereplication.

The role of analytical chemistry in exposure science: Focus on the aquatic environment

Exposure science, in its broadest sense, studies the interactions between stressors (chemical, biological, and physical agents) and receptors (e.g. humans and other living organisms, and non-living items like buildings), together with the associated pathways and processes potentially leading to negative effects on human health and the environment. The aquatic environment may contain thousands of compounds, many of them still unknown, that can pose a risk to ecosystems and human health. Due to the unquestionable importance of the aquatic environment, one of the main challenges in the field of exposure science is the comprehensive characterization and evaluation of complex environmental mixtures beyond the classical/priority contaminants to new emerging contaminants. The role of advanced analytical chemistry to identify and quantify potential chemical risks, that might cause adverse effects to the aquatic environment, is essential. In this paper, we present the strategies and tools that analytical chemistry has nowadays, focused on chromatography hyphenated to (high-resolution) mass spectrometry because of its relevance in this field. Key issues, such as the application of effect direct analysis to reduce the complexity of the sample, the investigation of the huge number of transformation/degradation products that may be present in the aquatic environment, the analysis of urban wastewater as a source of valuable information on our lifestyle and substances we consumed and/or are exposed to, or the monitoring of drinking water, are discussed in this article. The trends and perspectives for the next few years are also highlighted, when it is expected that new developments and tools will allow a better knowledge of chemical composition in the aquatic environment. This will help regulatory authorities to protect water bodies and to advance towards improved regulations that enable practical and efficient abatements for environmental and public health protection.

Comprehensive strategy for pesticide residue analysis through the production cycle of gilthead sea bream and Atlantic salmon

Plant ingredients and processed animal proteins are alternative feedstuffs for fish feeds in aquaculture. However, their use can introduce contaminants like pesticides that are not previously associated with marine Atlantic salmon and gilthead sea bream farming. This study covers the screening of around 800 pesticides by gas chromatography (GC) and liquid chromatography (LC) coupled to high resolution time-of-flight mass spectrometry in matrices throughout the entire marine food production chain. Prior to analysis of real-world samples, the screening methodology was validated for 252 pesticides to establish the screening detection limit. This was 0.01 mg kg^-1 for 113 pesticides (45%), 0.05 mg kg^-1 for 73 pesticides (29%) and >0.05 mg kg^-1 for 66 pesticides (26%). After that, a quantitative methodology based on GC coupled to tandem mass spectrometry with atmospheric pressure chemical ionization source (GC-APCI-MS/MS) was optimized for the pesticides found in the screening. Although several polar pesticides, of which pirimiphos methyl and chlorpyriphos-methyl were most dominant, were found in plant material and feeds based on these ingredients, none of them were observed in fillets of Atlantic salmon and gilthead sea bream fed on these feeds.

Silencing of a second dimethylallyltryptophan synthase of Penicillium roqueforti reveals a novel clavine alkaloid gene cluster

Penicillium roqueforti produces several prenylated indole alkaloids, including roquefortine C and clavine alkaloids. The first step in the biosynthesis of roquefortine C is the prenylation of tryptophan-derived dipeptides by a dimethylallyltryptophan synthase, specific for roquefortine biosynthesis (roquefortine prenyltransferase). A second dimethylallyltryptophan synthase, DmaW2, different from the roquefortine prenyltransferase, has been studied in this article. Silencing the gene encoding this second dimethylallyltryptophan synthase, dmaW2, proved that inactivation of this gene does not prevent the production of roquefortine C, but suppresses the formation of other indole alkaloids. Mass spectrometry studies have identified these compounds as isofumigaclavine A, the pathway final product and prenylated intermediates. The silencing does not affect the production of mycophenolic acid and andrastin A. A bioinformatic study of the genome of P. roqueforti revealed that DmaW2 (renamed IfgA) is a prenyltransferase involved in isofumigaclavine A biosynthesis encoded by a gene located in a six genes cluster (cluster A). A second three genes cluster (cluster B) encodes the so-called yellow enzyme and enzymes for the late steps for the conversion of festuclavine to isofumigaclavine A. The yellow enzyme contains a tyrosine-181 at its active center, as occurs in Neosartorya fumigata, but in contrast to the Clavicipitaceae fungi. A complete isofumigaclavines A and B biosynthetic pathway is proposed based on the finding of these studies on the biosynthesis of clavine alkaloids.