Mass spectrometric determination of acromelic acid A from a new poisonous mushroom: Clitocybe amoenolens

Family matters inside the order Agaricales: systematic reorganization and classification of incertae sedis clitocyboid, pleurotoid and tricholomatoid taxa based on an updated 6-gene phylogeny

The phylogenetic position of several clitocyboid/pleurotoid/tricholomatoid genera previously considered incertae sedis is here resolved using an updated 6-gene dataset of Agaricales including newly sequenced lineages and more complete data from those already analyzed before. Results allowed to infer new phylogenetic relationships, and propose taxonomic novelties to accommodate them, including up to ten new families and a new suborder. Giacomia (for which a new species from China is here described) forms a monophyletic clade with Melanoleuca (Melanoleucaceae) nested inside suborder Pluteineae, together with the families Pluteaceae, Amanitaceae (including Leucocortinarius), Limnoperdaceae and Volvariellaceae. The recently described family Asproinocybaceae is shown to be a later synonym of Lyophyllaceae (which includes also Omphaliaster and Trichocybe) within suborder Tricholomatineae. The families Biannulariaceae, Callistosporiaceae, Clitocybaceae, Fayodiaceae, Macrocystidiaceae (which includes Pseudoclitopilus), Entolomataceae, Pseudoclitocybaceae (which includes Aspropaxillus), Omphalinaceae (Infundibulicybe and Omphalina) and the new families Paralepistaceae and Pseudoomphalinaceae belong also to Tricholomatineae. The delimitation of the suborder Pleurotineae (= Schizophyllineae) is discussed and revised, accepting five distinct families within it, viz. Pleurotaceae, Cyphellopsidaceae, Fistulinaceae, Resupinataceae and Schizophyllaceae. The recently proposed suborder Phyllotopsidineae (= Sarcomyxineae) is found to encompass the families Aphroditeolaceae, Pterulaceae, Phyllotopsidaceae, Radulomycetaceae, Sarcomyxaceae (which includes Tectella), and Stephanosporaceae, all of them unrelated to Pleurotaceae (suborder Pleurotineae) or Typhulaceae (suborder Typhulineae). The new family Xeromphalinaceae, encompassing the genera Xeromphalina and Heimiomyces, is proposed within Marasmiineae. The suborder Hygrophorineae is here reorganized into the families Hygrophoraceae, Cantharellulaceae, Cuphophyllaceae, Hygrocybaceae and Lichenomphaliaceae, to homogenize the taxonomic rank of the main clades inside all suborders of Agaricales. Finally, the genus Hygrophorocybe is shown to represent a distinct clade inside Cuphophyllaceae, and the new combination H. carolinensis is proposed. Taxonomic novelties: New suborder: Typhulineae Vizzini, Consiglio & P. Alvarado. New families: Aphroditeolaceae Vizzini, Consiglio & P. Alvarado, Melanoleucaceae Locq. ex Vizzini, Consiglio & P. Alvarado, Paralepistaceae Vizzini, Consiglio & P. Alvarado, Pseudoomphalinaceae Vizzini, Consiglio & P. Alvarado, Volvariellaceae Vizzini, Consiglio & P. Alvarado, Xeromphalinaceae Vizzini, Consiglio & P. Alvarado. New species: Giacomia sinensis J.Z. Xu. Stat. nov.: Cantharellulaceae (Lodge, Redhead, Norvell & Desjardin) Vizzini, Consiglio & P. Alvarado, Cuphophyllaceae (Z.M. He & Zhu L. Yang) Vizzini, Consiglio & P. Alvarado, Hygrocybaceae (Padamsee & Lodge) Vizzini, Consiglio & P. Alvarado, Lichenomphaliaceae (Lücking & Redhead) Vizzini, Consiglio & P. Alvarado. New combination: Hygrophorocybe carolinensis (H.E. Bigelow & Hesler) Vizzini, Consiglio & P. Alvarado. New synonyms: Sarcomyxineae Zhu L. Yang & G.S. Wang, Schizophyllineae Aime, Dentinger & Gaya, Asproinocybaceae T. Bau & G.F. Mou. Incertae sedis taxa placed at family level: Aphroditeola Redhead & Manfr. Binder, Giacomia Vizzini & Contu, Hygrophorocybe Vizzini & Contu, Leucocortinarius (J.E. Lange) Singer, Omphaliaster Lamoure, Pseudoclitopilus Vizzini & Contu, Resupinatus Nees ex Gray, Tectella Earle, Trichocybe Vizzini. New delimitations of taxa: Hygrophorineae Aime, Dentinger & Gaya, Phyllotopsidineae Zhu L. Yang & G.S. Wang, Pleurotineae Aime, Dentinger & Gaya, Pluteineae Aime, Dentinger & Gaya, Tricholomatineae Aime, Dentinger & Gaya. Resurrected taxa: Fayodiaceae Jülich, Resupinataceae Jülich. Citation: Vizzini A, Alvarado P, Consiglio G, Marchetti M, Xu J (2024). Family matters inside the order Agaricales: systematic reorganization and classification of incertae sedis clitocyboid, pleurotoid and tricholomatoid taxa based on an updated 6-gene phylogeny. Studies in Mycology 107: 67-148. doi: 10.3114/sim.2024.107.02.

Dysregulation of REV-ERBα impairs GABAergic function and promotes epileptic seizures in preclinical models

To design potentially more effective therapies, we need to further understand the mechanisms underlying epilepsy. Here, we uncover the role of Rev-erbα in circadian regulation of epileptic seizures. We first show up-regulation of REV-ERBα/Rev-erbα in brain tissues from patients with epilepsy and a mouse model. Ablation or pharmacological modulation of Rev-erbα in mice decreases the susceptibility to acute and chronic seizures, and abolishes diurnal rhythmicity in seizure severity, whereas activation of Rev-erbα increases the animal susceptibility. Rev-erbα ablation or antagonism also leads to prolonged spontaneous inhibitory postsynaptic currents and elevated frequency in the mouse hippocampus, indicating enhanced GABAergic signaling. We also identify the transporters Slc6a1 and Slc6a11 as regulators of Rev-erbα-mediated clearance of GABA. Mechanistically, Rev-erbα promotes the expressions of Slc6a1 and Slc6a11 through transcriptional repression of E4bp4. Our findings propose Rev-erbα as a regulator of synaptic function at the crosstalk between pathways regulating the circadian clock and epilepsy.

Nicotinic acid treatment for Paralepistopsis acromelalga intoxication: assessment using magnetic resonance imaging

CONTEXT

Paralepistopsis acromelalga, formerly known as Clitocybe acromelalga, is a rare poisonous mushroom. The mycotoxins in this mushroom cause symptoms resembling those of erythromelalgia; however, its pathogenesis remains unclear. In this report, a patient who received nicotinic acid treatment for P. acromelalga poisoning and radiological evaluation for erythromelalgia has been presented. Case detail: A 59-year-old woman was hospitalized for redness, swelling, and burning pain in her extremities that rendered difficulty in walking, and a diagnosis of P. acromelalga poisoning was made by detailed interview and mushroom identification. She was treated with intravenous nicotinic acid for 17 days followed by oral nicotinic acid amide for 2 months. She exhibited rapid symptomatic improvement and walked independently after 11 days of initial treatment. Initial MRI of her feet revealed toe-dominated subcutaneous thickening. After nicotinic acid treatment, those radiological findings improved dramatically.

DISCUSSION

The subcutaneous thickening evident on MRI indicated P. acromelalga poisoning-induced erythromelalgia involved subcutaneous inflammatory edema. The typical duration of edema without treatment is more than a month. The improvement on MRI after nicotinic acid treatment indicated that the adequate vasodilation induced by nicotinic acid contributed to resolution of the symptoms. Nicotinic acid was associated with the improvement of the edematous changes caused by the P. acromelalga intoxication.

Toxicity of Non-protein Amino Acids to Humans and Domestic Animals

Non-protein amino acids are common in plants and are present in widely consumed animal feeds and human foods such as alfalfa ( Medicago sativa), which contains canavanine, and lentil ( Lens culinaris), which contains homoarginine. Some occur in wild species that are inadvertently harvested with crop species. Some nonprotein amino acids and metabolites can be toxic to humans, e.g. Lathyrus species contain a neurotoxic oxalyl-amino acid. Some potential toxins may be passed along a food chain via animal intermediates. The increased interest in herbal medicines in the Western countries will increase exposure to such compounds.

Excitatory actions of mushroom poison (acromelic acid) on unmyelinated muscular afferents in the rat

Ingestion of a poisonous mushroom, Clitocybe acromelalga, results in strong and long-lasting allodynia, burning pain, redness and swelling in the periphery of the body. Acromelic acid (ACRO), a kainate analogue isolated from the mushroom, is assumed to be involved in the poisoning. ACRO has two isomers, ACRO-A and ACRO-B. The potency of ACRO-A is a million times higher than that of ACRO-B for induction of allodynia when intrathecally administered in mice. The effect of ACRO on the primary afferents of somatic tissues remains largely unknown. The aim of the present study was to examine the effect of ACRO-A on the response behavior of unmyelinated afferents in the skeletal muscle. For this purpose single fiber recordings of C-afferents were made from rat extensor digitorum longus (EDL) muscle-common peroneal nerve preparations in vitro. Intramuscular injections of ACRO-A at three different concentrations (10(-12), 10(-10) and 10(-8)M, 5 microl over 5s) near the receptive field in the EDL muscle elicited excitation of C-afferents (12%, 50% and 44%, respectively). ACRO-A at the concentration of 10(-10)M induced the strongest excitation. The incidence of ACRO-A responsive fibers at the concentration of 10(-10) and 10(-8)M was significantly higher than that at 10(-12)M. The responses to mechanical and heat stimulations did not differ between ACRO-A sensitive and insensitive fibers. These results clearly demonstrated the powerful excitatory action of ACRO-A on mechanosensitive unmyelinated afferents in the rat skeletal muscle.

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.