Russula Subnigricans Research Articles

Discrimination of lethal Russula subnigricans from wild edible and morphologically similar mushrooms in the genus Russula using SCAR markers

Russula is a diverse genus of mushrooms that is consumed worldwide. Russula subnigricans is a lethal species that causes myotoxicity upon ingestion. It is morphologically similar to wild foraged species, including R. nigricans and R. densifolia. Misidentification of these mushrooms can lead to severe food poisoning. Several PCR-based approaches have been used to overcome this problem. In this study, 22 samples of wild edible Russula species were collected, and five clinical samples of R. subnigricans leftovers were obtained. Based on the sequence data of the internal transcribed spacer, the phylogenetic trees revealed that these 27 samples could be classified into well-established clades of six subgenera. Fifty arbitrary primers were used in high annealing temperature rapid amplified polymorphic DNA (HAT-RAPD) technique to screen polymorphic bands among R. subnigricans, R. nigricans, R. densifolia, and other edible species. Distinctive RAPD fragments were obtained from 11 primers and used in sequence characterized amplified region (SCAR) technique. Three pairs of species-specific SCAR primers were selected to distinguish lethal R. subnigricans, R. nigricans, and R. densifolia with SCAR markers of 213, 420, and 609 bp, respectively. Ten-fold sensitivity test revealed that the SCAR marker of R. subnigricans could be detected at DNA template concentrations as low as 30 pg/μL. This marker could detect the presence of lethal R. subnigricans even at 1% in a cooked sample of mixed mushroom remnants. The developed SCAR markers ensured rapid and accurate diagnosis of suspected myotoxic mushrooms, thereby reducing the risk of severe foodborne illness and death.

Multiplex TaqMan real-time PCR assay for high-throughput identification of highly toxic mushroom species-induced foodborne poisoning

The highly toxic Amanita species, Russula subnigricans, and Lepiota brunneoincarnata are the major mushroom types causing mushroom poisoning fatalities worldwide, which seriously endanger human life and health. However, the detection method for the simultaneous identification of these highly toxic mushroom types is scarce. In this study, a one-tube multiplex TaqMan real-time PCR assay was established for simultaneous detection of the highly toxic mushroom species from three genera. The developed assay could simultaneously detect at least 6 highly toxic Amanita species and specially identify R. subnigricans and L. brunneoincarnata without the cross-reaction in 37 mushroom species. The method detection limits were 0.1 pg/μL, 1 pg/μL, and 0.1 pg/μL DNA for highly toxic Amanita species, R. subnigricans, and L. brunneoincarnata with high amplification efficiency. Moreover, the multiplex real-time PCR assay was successfully applied to the cooked mushroom. The developed method is expected to become an effective tool for high-throughput identification of foodborne poisoning associated with these highly toxic mushroom species.

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.

Mushroom Poisoning Outbreaks - China, 2020.

Summary What is already known about this topic? Acute liver failure, rhabdomyolysis, acute renal failure, and hemolysis caused by poisonous mushrooms are the most important mushroom poisoning threats to the Chinese population. The most notorious lethal mushrooms are the species from genera Amanita, Lepiota, and Galerina that cause acute liver failure, and Russula subnigricans that leads to rhabdomyolysis. What is added by this report? In 2020, the total number of investigations reached 676, involving an estimated 102 species of poisonous mushrooms, 24 of which were newly recorded in China. Gyromitra venenata was newly discovered in incidents in Yunnan and Guizhou provinces and were the first reported poisonings due to gyromitrins in China since 2000. The rare poisoning Shiitake mushroom dermatitis was recorded in China. Hemolysis poisoning caused by Paxillus involutus was recorded for the second time since the beginning of the new century, resulting in one death in Inner Mongolia Autonomous Region. What are the implications for public health practice? Promoting knowledge about safe consumption of mushrooms is essential to reduce mushroom poisonings. It is not wise to collect and eat wild mushrooms. For southwestern provinces such as Yunnan, especially, caution must be exercised with unfamiliar mushroom species.

The mitochondrial genome of a wild toxic mushroom, Russula subnigricans

Russula subnigricans is a wild toxic mushroom in the world. In this study, we present the 60,949 bp mitochondrial genome of R. subnigricans with a GC content of 21%. The mtDNA assembly consists of 60 genes, which including 14 standard protein-coding genes, two rRNA genes, 25 tRNA genes and 19 free-standing open reading frames (ORFs). Phylogenetic analysis was performed using 14 protein-coding genes, the results showed that the R. subnigricans had high homology with other Russula species.

Species identification, geographical distribution, poisoning symptoms and medical treatment of russula subnigricans

Objective To study species identification, geographical distribution poisoning symptoms of russula subnigricans in order to provide guidelines of prevention and proper treatment. Methods Based on the data of epidemiological investigation, clinical treatment data and suspicious poisonous mushrooms, the collected mushroom were identified by morphological and molecular analysis, and the poisoning symptoms and medical treatment of R. subnigricans were systematically summarized. Results From the present two poisoning case, Epidemiological investigation showed that both patients ate some mushrooms in an appearance of fired charcoal(huotanjuncalled by layman) in the evening on July 26th, 2015. The incubation period was 2-3 hours. The main poisoning symptoms were nausea, vomiting, myalgia, typical soy urine, rapid increased in serum creatine kinase (CK), alanine transaminase (ALT), aspartate aminotransferase (AST), creatine kinase MB (CK-MB) and serum creatinine (sCr) were found. Finally patients fell in kidney failure and respiratory failure. All these symptoms met the typical manifestion of mushroom poisoning reported caused by R. subnigricans. These two patients were treated with hemoperfusion, continuous veno-venous hemofiltration (CVVH), liver protecting treatment, protective renal treatment and antioxidant therapy.One patient died after 40 days after admission.Other patient was transferred to a better facility and experienced physicians, and the other patient was still in hospital without any improvement up to the end of Feb. 2016 with a gloomy prospect. The mushroom eaten by the patients was identified as russula subnigricans though morphological and molecular analysis. Conclusions Russula subnigricans is a very toxic mushroom, widely distributed in southern China. Morphological and molecular analysis (using ITS sequence) is suitable for species identification of R. subnigricans. The incubation period of R. subnigricans poisioning is usually short, its target organ is mainly striated muscle, and severe patients usually have unfavourable outcome. Key words: Poisonous mushrooms; Russula subnigricans; Species identification; Geographical distribution; Medical treatment

Identification of Cyclopropylacetyl-(R)-carnitine, a Unique Chemical Marker of the Fatally Toxic Mushroom Russula subnigricans.

A toxic mushroom, Russula subnigricans, causes fatal poisoning by mistaken ingestion. In spite of the potent bioactivity, the responsible toxin had not been identified for about 50 years since its first documentation. Recently, we isolated an unstable toxin and determined the structure. The slow elucidation was partly due to the instability of the toxin and also due to misidentification of R. subnigricans for similar mushrooms. To discriminate genuine Russula subnigricans from similar unidentified Russula species, we searched for a unique chemical marker contained in the mushroom. Cyclopropylacetyl-(R)-carnitine specific to R. subnigricans was identified as a novel compound whose (1)H-NMR signals appearing in the upfield region were easily recognizable among the complicated signals of the crude extract.

A new species of <em>Russula</em>, subgenus <em>Compactae</em> from California

A new species of Russula , subgenus Compactae , is described growing in association with coast live oak ( Quercus agrifolia ) in California. This species has previously been referred to locally as Russula subnigricans Hongo and Russula eccentrica Peck, but morphological and DNA evidence show that it is a distinct species which we call R. cantharellicola . Our analysis shows that there are multiple clades of what is called R. subnigricans , and that the California species clearly falls within one of those clades. As R. subnigricans has caused deaths in Japan, China, and Taiwan, the California species should be cautioned as potentially dangerous to those who consume it.

Investigation and analysis of 102 mushroom poisoning cases in Southern China from 1994 to 2012

Mushroom poisoning is the main cause of mortality in food poisoning incidents in China. Although some responsible mushroom species have been identified, some were identified inaccuratly. This study investigated and analyzed 102 mushroom poisoning cases in southern China from 1994 to 2012, which involved 852 patients and 183 deaths, with an overall mortality of 21.48 %. The results showed that 85.3 % of poisoning cases occurred from June to September, and involved 16 species of poisonous mushroom: Amanita species (A. fuliginea, A. exitialis, A. subjunquillea var. alba, A. cf. pseudoporphyria, A. kotohiraensis, A. neoovoidea, A. gymnopus), Galerina sulciceps, Psilocybe samuiensis, Russula subnigricans, R. senecis, R. japonica, Chlorophyllum molybdites, Paxillus involutus, Leucocoprinus cepaestipes and Pulveroboletus ravenelii. Six species (A. subjunquillea var. alba, A. cf. pseudoporphyria, A. gymnopus, R. japonica, Psilocybe samuiensis and Paxillus involutus) are reported for the first time in poisoning reports from China. Psilocybe samuiensis is a newly recorded species in China. The genus Amanita was responsible for 70.49 % of fatalities; the main lethal species were A. fuliginea and A. exitialis. Russula subnigricans caused 24.59 % of fatalities, and five species showed mortality >20 % (A. fuliginea, A. exitialis, A. subjunquillea var. alba, R. subnigricans and Paxillus involutus). Mushroom poisoning symptoms were classified from among the reported clinical symptoms. Seven types of mushroom poisoning symptoms were identified for clinical diagnosis and treatment in China, including gastroenteritis, acute liver failure, acute renal failure, psychoneurological disorder, hemolysis, rhabdomyolysis and photosensitive dermatitis.

Mushroom toxins: a forensic toxicological review

Mushrooms are ubiquitous in the world. Amateur hunters harvest mushrooms growing in forests to enjoy eating them as seasonal delicacies, and occasionally they cause poisonings and even deaths. In this review, mushroom toxins are tabulated according to mushroom species, symptoms, toxicities and analytical methods on the basis of references. Second, because we constructed a method for analysis of amatoxins, the most virulent mushroom toxins, by liquid chromatography-time-of-flight-mass spectrometry, we introduce it for use in forensic toxicology. Third, an extensive poisoning incident after consumption of the usually edible mushroom Pleurocybella porrigens took place in nine prefectures in Japan from September to December 2004, resulting in 59 poisoned people including 19 deaths; this incident is briefly described and discussed in relation to its causative toxin(s). Finally, we present the chemical structures of new toxins purified from the highly toxic mushrooms Podostroma cornu-damae and Russula subnigricans; their structures were very unique, and the toxicities were comparable to those of amatoxins. From the forensic toxicological point of view, reports on sophisticated methodology for analyses of mushroom toxins seem to be too scant even for the well-known toxins. Hereafter, a number of toxic mushrooms and their new toxins are expected to be disclosed, especially because of environmental changes such as the global warming phenomenon.

Chlorinated Hydroquinone Derivatives of Fruiting Body of Russula subnigricans

The 95% aqueous EtOH extract was obtanied from the fruiting body of Russula subnigricans. Repeated silica gel column chromatography and preparative TLC afforded one fatty acid and three chlorinated hydroquinone derivatives. They were identified as nonadecanoic acid (1), 2,6-dichloro-4-methoxyphenol (2), russuphelin A (3), and russuphelin E (4) on the basis of several spectral data (MS, <TEX>$^1H$</TEX> and <TEX>$^{13}C$</TEX>-NMR, including HMBC).

Identification of the toxic trigger in mushroom poisoning

We have isolated the small, highly strained carboxylic acid cycloprop-2-ene carboxylic acid from the Asian toxic mushroom Russula subnigricans. This compound is responsible for fatal rhabdomyolysis, a new type of mushroom poisoning that is indicated by an increase in serum creatine phosphokinase activity in mice. We found that polymerization of the compound at high concentrations via ene reaction abolishes its toxicity.

New Syndromes in Mushroom Poisoning

Several new mushroom poisoning syndromes have been described since the early 1990s. In these syndromes, the onset of symptoms generally occurs >6 hours after ingestion. Treatment is mainly supportive. The syndrome induced by Amanita smithiana/proxima consists of acute tubulopathy, which appears earlier and does not have the same poor prognosis as the orellanine-induced syndrome. It has been described since 1992 in the US and Canada with A. smithiana; in France, Spain and Italy with A. proxima; and in Japan with A. pseudoporphyria. The responsible toxin is probably 2-amino-4,5-hexadienoic acid. The erythromelalgia syndrome has been described as early as the late 19th century in Japan and South Korea with Clitocybe acromelalga, and since 1996 in France and then Italy with C. amoenolens. Responsible toxins are probably acromelic acids identified in both species. Several cases of massive rhabdomyolysis have been reported since 1993 in France and 2001 in Poland after ingestion of large amounts of an edible and, until then, valuable species called Tricholoma equestre. These cases of rhabdomyolysis are associated with respiratory and cardiac (myocarditis) complications leading to death. Rhabdomyolysis with an apparently different mechanism was described in Taiwan in 2001 with Russula subnigricans. Finally, cases of encephalopathy were observed twice after ingestion of Hapalopilus rutilans in Germany in 1992 and Pleurocybella porrigens in Japan in 2004, where a convulsive encephalopathy outbreak was reported in patients with history of chronic renal failure.

Syndromic diagnosis and management of confirmed mushroom poisonings

To assess the evolving global epidemiology of mushroom poisoning and to identify new and emerging mushroom poisonings and their treatments, a descriptive analysis and review of the world's salient scientific literature on mushroom poisoning was conducted. Data sources from observation studies conducted over the period 1959-2002, and describing 28,018 mushroom poisonings since 1951, were collected from case reports, case series, regional descriptive studies, meta-analyses, and laboratory studies of mushroom poisonings and the toxicokinetics of mycotoxins. Studies included in the review were selected by a MEDLINE search, 1966-2004, an Ovid OLDMEDLINE search, 1951-1965, and a medical library search for sources published before 1951. To better guide clinicians in establishing diagnoses and implementing therapies, despite confusing ingestion histories, data were extracted to permit an expanded syndromic classification of mushroom poisoning based on presentation timing and target organ systemic toxicity. The final 14 major syndromes of mushroom poisoning were stratified first by presentation timing and then by target organ systemic toxicity and included early (<6 hrs), late (6-24 hrs), and delayed syndromes (> or =1 day). There were eight early syndromes (four neurotoxic, two gastrointestinal, two allergic); three late syndromes (hepatotoxic, accelerated nephrotoxic, erythromelalgia); and three delayed syndromes (delayed nephrotoxic, delayed neurotoxic, rhabdomyolysis). Four new mushroom poisoning syndromes were classified including accelerated nephrotoxicity (Amanita proxima, Amanita smithiana), rhabdomyolysis (Tricholoma equestre, Russula subnigricans), erythromelalgia (Clitocybe amoenolens, Clitocybe acromelalgia), and delayed neurotoxicity (Hapalopilus rutilans). In addition, data sources were stratified by three chronological time periods with >1,000 confirmed mushroom ingestions reported and tested for any statistically significant secular trends in case fatalities from mushroom ingestions over the entire study period, 1951-2002. Since the 1950s, reports of severe and fatal mushroom poisonings have increased worldwide. Clinicians must consider mushroom poisoning in the evaluation of all patients who may be intoxicated by natural substances. Since information on natural exposures is often insufficient and incorrect, a new syndromic classification of mushroom poisoning is recommended to guide clinicians in making earlier diagnoses, especially in cases where only advanced critical care, including organ transplantation, may be life saving.

Evolving global epidemiology, syndromic classification, general management, and prevention of unknown mushroom poisonings

To assess the evolving global epidemiology of mushroom poisoning and to identify new and emerging mushroom poisonings and their treatments, a descriptive analysis and review of the world's salient scientific literature on mushroom poisoning was conducted. Data sources from observation studies conducted over the period 1959-2002 and describing 28,018 mushroom poisonings since 1951 were collected from case reports, case series, regional descriptive studies, meta-analyses, and laboratory studies of mushroom poisonings and the toxicokinetics of mycotoxins. Studies included in the review were selected by a MEDLINE search, 1966-2004, an Ovid OLDMEDLINE search, 1951-1965, and a medical library search for sources published before 1951. To better guide clinicians in establishing diagnoses and implementing therapies, despite confusing ingestion histories, data were extracted to permit an expanded syndromic classification of mushroom poisoning based on presentation timing and target organ systemic toxicity. The final 14 major syndromes of mushroom poisoning were stratified first by presentation timing and then by target organ systemic toxicity and included early (<6 hrs), late (6-24 hrs), and delayed syndromes (> or =1 day). There were eight early syndromes (four neurotoxic, two gastrointestinal, two allergic); three late syndromes (hepatotoxic, accelerated nephrotoxic, erythromelalgia); and three delayed syndromes (delayed nephrotoxic, delayed neurotoxic, rhabdomyolysis). Four new mushroom poisoning syndromes were classified including accelerated nephrotoxicity (Amanita proxima, Amanita smithiana), rhabdomyolysis (Tricholoma equestre, Russula subnigricans), erythromelalgia (Clitocybe amoenolens, Clitocybe acromelalgia), and delayed neurotoxicity (Hapalopilus rutilans). In addition, data sources were stratified by three chronological time periods with >1,000 confirmed mushroom ingestions reported and tested for any statistically significant secular trends in case fatalities from mushroom ingestions over the entire study period, 1951-2002. Since the 1950s, reports of severe and fatal mushroom poisonings have increased worldwide. Clinicians must consider mushroom poisoning in the evaluation of all patients who may be intoxicated by natural substances. Since information on natural exposures is often insufficient and incorrect, a new syndromic classification of mushroom poisoning is recommended to guide clinicians in making earlier diagnoses, especially in cases where only advanced critical care, including organ transplantation, may be life saving.

Rhabdomyolysis: An unusual feature with mushroom poisoning

Rhabdomyolysis resulting from mushroom poisoning previously has been unreported in the literature. We present an outbreak of Russula subnigricans poisoning with rhabdomyolysis. The most severely ill patient presented with rhabdomyolysis, severe electrolyte disturbance (hyperkalemia, hypocalcemia), respiratory failure, acute renal failure, pulmonary edema, ventricular tachycardia, and circulatory shock. Mycotoxin may be the cause of rhabdomyolysis. In areas where mushroom gathering is common, mushroom poisoning should be included in the differential diagnosis of rhabdomyolysis. © 2001 by the National Kidney Foundation, Inc.

Russuphelol, a novel optically active chlorohydroquinone tetramer from the mushroom Russula subnigricans

A novel optically active chlorohydroquinone tetramer, russuphelol was isolated from the fruit bodies of the mushroom Russula subnigricans Hongo . The structure ( 1 ) was determined on the basis of the spectroscopic analysis. A novel optically active chlorohydroquinone tetramer, russuphelol was isolated from the mushroom Russula subnigricans . The structure ( 1 ) was determined on the basis of the spectroscopic analysis.

Russuphelins B, C, D, E and F, new cytotoxic substances from the mushroom Russula subnigricans Hongo.

Five new chlorinated phenyl ethers, russuphelins B (2), C (3), D (4), E (5) and F (6) have been isolated from the mushroom Russula subnigricans Hongo, and their structures were elucidated by spectroscopic and chemical means. Russuphelins B (2), C (3) and D (4) exhibited cytotoxic activity in vitro against P388 leukemia cells.

Russuphelin A, a new cytotoxic substance from the mushroom Russula subnigricans Hongo.

A new cytotoxic substance, designated russuphelin A (1), has been isolated from the mushroom Russula subnigricans Hongo (Basidiomycetes). The structure was elucidated as 2,6-bis(2,6-dichloro-4-hydroxyphenyloxy)-1,4-dimethoxy-benzene on the basis of spectroscopic data and confirmed by total synthesis.