Using a DNA mini-barcode within the ITS region to identify toxic Amanita in mushroom poisoning cases

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.

Survey of Edible Amanita in Northern Thailand and Their Nutritional Value, Total Phenolic Content, Antioxidant and α-Glucosidase Inhibitory Activities

Edible wild mushrooms are extremely popular among consumers and are highly valued for their potential economic benefits in northern Thailand. In this present study, a total of 19 specimens of edible Amanita were collected during investigations of wild edible mushrooms in northern Thailand during the period from 2019 to 2022. Their morphological characteristics and the phylogenetic analyses of the internal transcribed spacer (ITS) and partial large subunit (nrLSU) of ribosomal RNA, RNA polymerase II second-largest subunit (rpb2) and partial translation elongation factor 1-alpha (tef-1) indicated that the collected specimens belonged to A. hemibapha, A. pseudoprinceps, A. rubromarginata, A. subhemibapha, and Amanita section Caesareae. This is the first report of A. pseudoprinceps and A. subhemibapha from Thailand. Full descriptions, illustrations and a phylogenetic placement of all specimens collected in this study are provided. Subsequently, the nutritional composition and total phenolic content, as well as the antioxidant and α-glucosidase inhibitory activities, of each species were investigated. The results indicate that the protein contents in both A. pseudoprinceps and A. subhemibapha were significantly higher than in A. hemibapha and A. rubromarginata. The highest total phenolic content was found in the extract of A. pseudoprinceps. In terms of antioxidant properties, the extract of A. pseudoprinceps also exhibited significantly high antioxidant activity by 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. However, the extract of A. rubromarginata had the lowest total phenolic content and level of antioxidant activity. Additionally, α-glucosidase inhibitory activity varied for different Amanita species and the highest level of α-glucosidase inhibitory activity was found in the extract of A. pseudoprinceps. This study provides valuable information on the nutrient content, phenolic content and the antioxidant and α-glucosidase inhibitory potential of edible Amanita species found in northern Thailand.

Development of a loop-mediated isothermal amplification assay for the rapid detection of Russula subnigricans and Russula japonica

Russula subnigricans is the only deadly species in the genus Russula with a mortality rate of more than 50%, and Russula japonica is the most common poisonous species, making rapid species identification in mushroom poisoning incidents extremely important. The main objective of this study was to develop a rapid, specific, sensitive, and simple loop-mediated isothermal amplification (LAMP) assay for the detection of R. subnigricans and R. japonica. Two sets of species-specific LAMP primers targeting internal transcribed spacer (ITS) regions were designed to identify R. subnigricans and R. japonica. The results demonstrated that while LAMP could specifically detect R. subnigricans and R. japonica, the polymerase chain reaction (PCR) could not distinguish R. subnigricans from Russula nigricans. In addition, the results demonstrated that, compared to electrophoresis-LAMP and real-time quantitative LAMP (RT-qLAMP), the detection sensitivity of HNB-LAMP (a mixture of LAMP with hydroxy naphthol blue (HNB) dye) for R. subnigricans could reach 0.5 pg/μl and was 100-fold higher than that of PCR. The LAMP reaction could be completed in 45 min, which is much faster than the conventional PCR. In the future, LAMP can be used a quick, specific, and sensitive detection tool in various fields.

Draft Genomes of Six Wild Poisonous Mushrooms

Foodborne illnesses caused by wild mushroom poisoning occur globally and have led to food safety concerns. Here, we reported de novo genome assemblies of the six most commonly encountered toxic mushrooms in Thailand. These comprised Amanita brunneitoxicaria, Cantharocybe virosa, Chlorophyllum molybdites, Entoloma mastoideum, Pseudosperma sp. and Russula subnigricans. The nuclear genome sizes of these species ranged from 40 to 77 Mb, with the number of predicted genes ranging from 5,375 to 14,099. The mitogenome sizes varied from 41,555 to 78,907 bp. The resulting draft genomes of these poisonous mushrooms provide insights into toxin-related genes that may be used to establish genetic markers for monitoring mushroom poisoning outbreaks.

Epidemiology and Economic Burden of an Outbreak of Cyclopeptide-Containing Mushroom Poisoning in the West of Iran

Little evidence is available on the epidemiological and economical dimensions of certain foodborne diseases such as wild mushroom poisoning. This study aimed to investigate the epidemiology and estimate the costs of poisoning with cyclopeptide-containing mushrooms in Kermanshah province in 2018. In this study, poisoning was investigated in different subgroups. The cost of illness method with a bottom-up approach was used to estimate the poisoning costs. Both direct and indirect costs of the poisoning were included in the analysis. The perspective of the study was society. Required data were obtained from the medical records of Imam Khomeini hospital and completed through a line survey with the patients. Two hundred eighty-three patients were poisoned in Kermanshah due to poisoning with cyclopeptide-containing mushrooms. Of 283 patients, 143 (50.53%) were men and 59.01% of patients were rural residents. About 43% of admissions were out-patient cases and ~40% of patients were hospitalized within 1-3 days. Also, eight patients were pronounced dead in the area. The total cost of poisoning with cyclopeptide-containing mushrooms in Kermanshah province was $ 1,259,349.26. Of that, $ 69,281.65 was related to direct medical costs and $ 10,727.23 was direct non-medical costs. The indirect costs of death were estimated to be $ 1,125,829.7. The current study revealed that there is a significant financial burden due to cyclopeptide-containing mushrooms on patients, the health system, and society as a whole. Further studies are recommended to clarify the epidemiological and economic burden of foodborne illnesses related to wild mushroom poisonings. Sharing the outputs with health authorities, and informing the general public are warranted to reduce the burden of such diseases.

Epidemiological analysis of wild mushroom poisoning in Zhejiang province, China, 2016-2018

Wild mushroom poisoning has been recognized as a global problem threatening human health. In this study, we aimed to explore characteristics of wild mushroom poisoning in Zhejiang province, China. From 2016 to 2018, 429 cases of wild mushroom poisoning were reported, and among them, there were 2 deaths and 84 hospitalizations, with the incidence of 0.2526 per 100,000 and the case fatality rate of 0.47%. Digestive symptoms were found in all cases. Systemic symptoms and signs, neurological symptoms, and urinary symptoms were found in 28.90% (124/429), 11.66% (50/429), and 4.90% (21/429) of the cases, respectively. The proportion of cases with incubation period <6 h was 85.78%, and those with ≥6 h accounted for 14.22%. The peak period of poisoning occurred from June to October annually. Quzhou (Moran's I = 1.242, p < .05) and Lishui (Moran's I = 0.759, p < .05) with mild climate, more mountains, and abundant rainfall were "hot spots" for the incidence of wild mushroom poisoning, showing a state of high-incidence aggregation. Epidemiological analysis showed that there were seasonal, high-incidence areas and high-risk groups in wild mushroom poisoning. The government should give early warning to high-incidence areas and strengthen publicity to high-risk groups before wild mushrooms mature every summer and autumn. In addition, we recommend that ordinary people not pick wild mushrooms outdoors for consumption, because it is difficult to distinguish whether wild mushrooms are poisonous and do not buy wild mushrooms of unknown sources.

Diversity, Dispersal and Mode of Reproduction of Amanita exitialis in Southern China

Amanita exitialis is a poisonous mushroom and has caused many deaths in southern China. In this study, we collected 118 fruiting bodies of A. exitialis from seven different sites in Guangdong Province in southern China and investigated their genetic relationships using 14 polymorphic molecular markers. These 14 markers grouped the 118 fruiting bodies into 20 multilocus genotypes. Among these 20 genotypes, eight were each found only once while the remaining 12 were each represented by two to 54 fruiting bodies. Interestingly, among the 12 shared genotypes, four were shared between/among local populations that were separated by as far as over 80 km, a result consistent with secondary homothallic reproduction and long-distance spore dispersal. Despite the observed gene flow, significant genetic differentiations were found among the local populations, primarily due to the over-representation of certain genotypes within individual local populations. STRUCTURE analyses revealed that the 118 fruiting bodies belonged to three genetic clusters, consistent with divergence within this species in this geographic region. Interestingly, we found an excess of heterozygous individuals at both the local and the total sample level, suggesting potential inbreeding depression and heterozygous advantage in these populations of A. exitialis. We discuss the implications of our results for understanding the life cycle, dispersal, and evolution of this poisonous mushroom.

Phylogenetic evidence revealed Cantharocybe virosa (Agaricales, Hygrophoraceae) as a new clinical record for gastrointestinal mushroom poisoning in Thailand

Epidemiological data showed increasing incidence rates of gastrointestinal (GI) mushroom syndrome in Thailand. This study therefore, aimed to identify suspected GI toxin-containing mushrooms using DNA sequence analyses of the internal transcribed spacer (ITS) region and the large subunit (LSU) of nuclear ribosomal DNA. GI toxins were also identified using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). 39 patients presented with poisoning symptoms, including nausea, vomiting, fatigue, abdominal pain, circulatory disturbances and diarrhea after ingesting wild mushrooms. The latent periods varied from 30 min to 4 h, but mostly between 1 and 2 h. Results of the ITS sequence-based identification revealed high similarities for the obtained clinical mushroom samples with the genus Cantharocybe H.E. Bigelow & A.H. SM. Maximum likelihood and Bayesian summary trees of combined ITS and LSU data confirmed that these toxic mushroom samples ingested by the patients belonged to Cantharocybe virosa (Manim. & K.B. Vrinda) T.K.A. Kumar. Detection of GI toxins using LC-QTOF-MS method revealed the presence of coprine in C. virosa. This study described the first outbreak of C. virosa poisoning in Thailand which resulted in severe cases of gastrointestinal irritation. To prevent such poisoning cases it is essential to educate the public not to gather any unidentified or unfamiliar wild mushrooms.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

Universal identification of lethal amanitas by using Hyperbranched rolling circle amplification based on α-amanitin gene sequences

Hyperbranched rolling circle amplification (HRCA) with a padlock probe (PLP) targeting the α-amanitin (α-AMA) gene, as a screening tool for the universal identification of lethal amanitas, was established in this study. With the isothermal HRCA assay, all of the lethal Amanita species tested from Phalloideae (10) were positive, while the non-Phalloideae Amanita species (15) and three amanitin-containing Lepiota and Galerina species were negative. Furthermore, the PLP based on α-AMA sequences from lethal Amanita species was effective for Amanita α-AMA, but not Amanita β-AMA or non-Amanita α-AMA. HRCA sensitivity was 100-fold higher than conventional PCR with a detection limit of 100 copies (recombinant plasmid containing α-AMA), and 0.2% lethal amanitas could be detected in dry mushroom blends. The HRCA method presented provided a rapid, specific, sensitive and low-cost identification tool for lethal amanitas.

A case study of Lepiota brunneoincarnata poisoning with endoscopic nasobiliary drainage in Shandong, China

The most frequently reported fatal Lepiota ingestions are due to L. brunneoincarnata. We present a case of L. brunneoincarnata poisoning with endoscopic nasobiliary drainage known to be the first in China. The patient suffered gastrointestinal symptoms 9 h post ingestion of mushrooms. The patient was hospitalized 4 days after eating the mushrooms with jaundice. The peak ALT, AST, APTT, TBIL and DBIL values of the patient were as follow: ALT, 2980 U/L (day 4 post ingestion); AST, 1910 U/L (day 4 post ingestion); APTT, 92.8 seconds (day 8 post ingestion), TBIL, 136 μmol/L (day 10 post ingestion), DBIL 74 μmol/L (day 10 post ingestion). UPLC-ESI-MS/MS was used to detect the peptide toxins in the mushroom and biological samples from the patient. We calculated that the patient may have ingested a total of 29.05 mg amatoxin from 300 g mushrooms, consisting of 19.91 mg α-amanitin, 9.1 mg β-amanitin, and 0.044 mg γ-amanitin. Amatoxins could be detected in bile even on day 6 after ingestion of L. brunneoincarnata. With rehydration, endoscopic nasobiliary drainage and intravenous infusion of Legalon SIL, the patient recovered after serious hepatotoxicity developed.

Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G.lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p < 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p < 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum.

Investigation and analysis of Galerina sulciceps poisoning in a canteen

INTRODUCTION

Guizhou Province in China has an abundant resource of wild mushrooms, including numerous poisonous species which contain various toxins. The mortality rate from wild mushroom poisoning has been high in this area in recent years. Galerina sulciceps is a dangerously toxic mushroom which can be fatal if ingested.

METHODS

we report on an epidemiological investigation of G. sulciceps poisoning which occurred in Duyun City of Guizhou Province. The characteristics of this species, its toxicity, observed clinical features, laboratory data, treatment modality, and prognosis were investigated in order to provide a reference point for the prevention and treatment of this kind of mushroom poisoning.

RESULTS

Thirteen employees showed toxic symptoms after ingesting wild mushrooms the previous day in a company canteen. Clinical manifestation varied from gastroenteritis to hepatic and renal dysfunction. Most of the 13 patients presented with nausea, vomiting, abdominal pain, diarrhea, and elevated levels of biochemical indices of hepatic and renal function, during which transaminase concentration peaked within 48-72 h. At 48 hours post-ingestion, all patients had hemodialysis, in addition to supportive care for hepatic and renal injury with oral Silibinin and Shenshuaining. All acute renal injury had resolved by day 10, and liver transaminases had trended toward normal in all patients and they were discharged. At follow-up in 30 days, both liver and renal function had completely recovered in all.

CONCLUSION

This poisoning occurs as a result of unintentional consumption of G. sulciceps, which is relatively rare in mushroom poisonings. All patients recovered fully after timely diagnosis and treatment. To prevent wild mushroom poisoning, the best preventive measure is to educate the public not to gather and eat any unidentified wild mushrooms.

Potential DNA barcodes for Melilotus species based on five single loci and their combinations

Melilotus, an annual or biennial herb, belongs to the tribe Trifolieae (Leguminosae) and consists of 19 species. As an important green manure crop, diverse Melilotus species have different values as feed and medicine. To identify different Melilotus species, we examined the efficiency of five candidate regions as barcodes, including the internal transcribed spacer (ITS) and two chloroplast loci, rbcL and matK, and two non-coding loci, trnH-psbA and trnL-F. In total, 198 individuals from 98 accessions representing 18 Melilotus species were sequenced for these five potential barcodes. Based on inter-specific divergence, we analysed sequences and confirmed that each candidate barcode was able to identify some of the 18 species. The resolution of a single barcode and its combinations ranged from 33.33% to 88.89%. Analysis of pairwise distances showed that matK+rbcL+trnL-F+trnH-psbA+ITS (MRTPI) had the greatest value and rbcL the least. Barcode gap values and similarity value analyses confirmed these trends. The results indicated that an ITS region, successfully identifying 13 of 18 species, was the most appropriate single barcode and that the combination of all five potential barcodes identified 16 of the 18 species. We conclude that MRTPI is the most effective tool for Melilotus species identification. Taking full advantage of the barcode system, a clear taxonomic relationship can be applied to identify Melilotus species and enhance their practical production.

Investigating and analyzing three cohorts of mushroom poisoning caused by Amanita exitialis in Yunnan, China

Amanita exitialis is a lethal mushroom found in China. Knowledge regarding taxonomic characterization, toxin detection, general poisoning conditions, clinical manifestations, laboratory examinations, and clinical treatments for this species is currently lacking. We investigated three A. exitialis mushroom poisoning cohorts in Yunnan Province in 2014 and 2015, involving 10 patients. Mushroom samples were identified by morphological and molecular studies. Ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry was used to detect the peptide toxins in the mushroom samples. Epidemiological information, clinical data, and results of laboratory examinations were collected and analyzed. The mushroom samples were all identified as A. exitialis. The average toxin concentration decreased from the cap to the stipe to the volva, and the average concentration of the peptide toxins decreased in the order of α-amanitin > phallacidin > β-amanitin > γ-amanitin. The latency period between ingestion and the onset of symptoms was 13.9 ± 2.1 h, and the time from ingestion to hospitalization was 49.6 ± 8.5 h. The most common symptoms were nausea and vomiting (100%). Four patients died from fulminant hepatic failure. Laboratory examinations showed that the alanine transaminase, aspartate transaminase, prothrombin time, and activated partial thromboplastin time levels peaked on the third day post-ingestion. Total bilirubin and direct bilirubin values peaked on day 7. The death group and the survival group had a similar variation trend of serological indexes, but the death group had a greater change. A. exitialis is an extremely dangerous mushroom and there is a need to educate the public to avoid picking and eating wild mushrooms that have not been definitively identified.