Mushroom poisoning contributes significantly to global foodborne diseases and related fatalities. Amanita mushrooms frequently cause such poisonings; however, identifying these toxic species is challenging due to the unavailability of fresh and intact samples. It is often necessary to analyze residues, vomitus, or stomach extracts to obtain DNA sequences for the identification of species responsible for causing food poisoning. This usually proves challenging to obtain usable DNA sequences that can be analyzed using conventional molecular biology techniques. Therefore, this study aimed to develop a DNA mini-barcoding method for the identification of Amanita species. Following the evaluation and optimization of universal primers for DNA mini-barcoding in Amanita mushrooms, we found that the internal transcribed spacer (ITS) gene sequence primer ITS-a was the most suitable DNA barcode primer for identifying Amanita species. Forty-three Amanita samples were subsequently amplified and sequenced. The sequences obtained were analyzed for intra- and inter-species genetic distances, and a phylogenetic tree was constructed. The findings indicated that the designed primers had strong universality among the Amanita samples and could accurately identify the target gene fragment with a length of 290 bp. Notably, the DNA mini-barcode accurately identified the 43 Amanita samples, demonstrating high consistency with the conventional DNA barcode. Furthermore, it effectively identified DNA from digested samples. In summary, this DNA mini-barcode is a promising tool for detecting accidental ingestion of toxic Amanita mushrooms. It may be used as an optimal barcode for species identification and traceability in events of Amanita-induced mushroom poisoning. KEY POINTS: • Development of a DNA mini-barcoding method for Amanita species identification without fresh samples. • The ITS-a primer set was optimized for robust universality in Amanita samples. • The mini-barcode is suitable for screening toxic mushroom species in mushroom poisoning cases.

In the human body, proteins secreted into peripheral blood vessels are known as the secretome, and they represent the physiological or pathological status of cells. The unique response of cells to toxin exposure can be confirmed via secretome analysis, which can be used to discover toxic mechanisms or exposure markers. Alpha-amanitin (α-AMA) is the most widely studied amatoxin and inhibits transcription and protein synthesis by directly interacting with RNA polymerase II. However, secretory proteins released during hepatic failure caused by α-AMA have not been fully characterized. In this study, we analyzed the secretome of α-AMA-treated Huh-7 cells and mice using a comparative proteomics technique. Overall, 1440 and 208 proteins were quantified in cell media and mouse serum, respectively. Based on the bioinformatics results for the commonly downregulated proteins in cell media and mouse serum, we identified complement component 3 (C3) as a marker for α-AMA-induced hepatotoxicity. Through western blot in cell secretome and C3 ELISA assays in mouse serum, we validated α-AMA-induced downregulation of C3. In conclusion, using comparative proteomics and molecular biology techniques, we found that α-AMA-induced hepatotoxicity reduced C3 levels in the secretome. We expect that this study will aid in identifying new toxic mechanisms, therapeutic targets, and exposure markers of α-AMA-induced hepatotoxicity.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s43188-022-00163-z.

Omphalotus japonicus is a major toxic mushroom in Japan. When food poisoning caused by O. japonicus occurs, quick and accurate identification using a method that does not rely on morphological discrimination is required. Because the loop-mediated isothermal amplification (LAMP) method meets these requirements, we developed a LAMP method for detecting O. japonicus. Amplification occurred within 60 min, and the presence or absence of O. japonicus was confirmed within 2 h, including the DNA extraction protocol. The LAMP method did not show cross-reactivity with 13 species of edible mushrooms, had high specificity toward O. japonicus, and had sufficient detection sensitivity even in a mixed mushroom sample containing 1% O. japonicus. Additionally, O. japonicus could be detected in simulated food poisoning samples of heated and digested mushrooms, and in actual food poisoning residual samples.