Acute mushroom poisoning of Amanita pseudosychnopyramis: A case report from Fujian, China with exact species identification and descriptive study.

Mushroom poisoning is a deeply concerning food safety problem that affects the public in China every year. Although there are statistics on the number of poisonings and incidents, there is a lack of data on the types of toxic mushrooms, clinical manifestations and toxins. A case of wild mushroom poisoning occurred in Xiamen. Descriptive epidemiological investigation, toxins detection, and morphological and phylogenetic identification were immediately performed. The patients exhibited typical neurotoxic symptoms after consuming wild mushrooms, including chills, vertigo, drowsiness, salivation and coma. The average incubation period was 30 min. Treatments that were adopted included fluid infusion, gastric lavage, catharsis, and liver protection treatment. All patients recovered within 10 days. The species was identified as Amanita pseudosychnopyramis, and its contents of muscarine, muscimol and ibotenic acid were 170.3 ± 5.9 mg/kg, 835.4 ± 43.1 mg/kg and 637.9 ± 54.8 mg/kg in dry weight, respectively, as detected by ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). To our knowledge, this is the first report of Amanita pseudosychnopyramis poisoning worldwide.

Reconstruction of a chicken BF2 protein complex and identification of binding nonamer peptides derived from avian influenza virus hemagglutinin.

In order to reconstruct the system for identification of short antigenic peptides, the chicken BF2 gene of Chinese Sanhuang (SH) chicken line was linked to the beta(2)m gene via (G4S)3, a linker encoding a 15-amino acid glycine-rich peptide, by splicing overlap extension PCR (SOE-PCR). The MBP-BF2-(G4S)3-beta(2)m fusion protein was expressed and purified in a pMAL-p2X/E. coli TB1 system. The purified MBP-BF2-(G4S)3-beta(2)m protein was cleaved by Factor Xa protease, and further purified by DEAE-Sepharose chromatography. The conformation of the BF2-(G4S)3-beta(2)m protein was determined by circular dichroism (CD). In addition, the refolded BF2-(G4S)3-beta2m protein was used to bind three predicted nonameric peptides derived from the hemagglutinins of the avian influenza virus (AIV) H5N1 and H9N2 subtypes. The BF2-(G4S)3-beta2m-associated peptides were detected by mass spectrometry. The molecular weights and amino acid sequences of the peptides were confirmed by primary and tandem mass spectrometry analysis, respectively. The results indicate that the secondary structures and predicted three-dimensional crystal structure of BF2-(G4S)3-beta(2)m are similar to those of the monomers of chicken BF2 and beta(2)m. The BF2-(G4S)3-beta(2)m protein could bind two of the three predicted nonamer peptides derived from AIV hemagglutinin. The experimental system demonstrated that the reconstructed BF2-(G4S)3-beta(2)m protein complex can be used to identify nonamer peptides, including T-cell epitopes in chicken.

Reconstruction of a swine SLA-I protein complex and determination of binding nonameric peptides derived from the foot-and-mouth disease virus.

No experimental system to date is available to identify viral T-cell epitopes in swine. In order to reconstruct the system for identification of short antigenic peptides, the swine SLA-2 gene was linked to the beta(2)m gene via (G4S)3, a linker encoding a 15-amino acid glycine-rich sequence (G4S)3, using splicing overlap extension-PCR (SOE-PCR). The maltose binding protein (MBP)-SLA-2-(G4S)3-beta(2)m fusion protein was expressed and purified in a pMAL-p2X/Escherichia coli TB1 system. The purified MBP-SLA-2-(G4S)3-beta(2)m protein was cleaved by factor Xa protease, and further purified by DEAE-Sepharose chromatography. The conformation of the SLA-2-(G4S)3-beta(2)m protein was determined by circular dichroism (CD) spectrum. In addition, the refolded SLA-2-(G4S)3-beta(2)m protein was used to bind three nonameric peptides derived from the foot-and-mouth disease virus (FMDV) O subtype VP1. The SLA-2-(G4S)3-beta(2)m-associated peptides were detected by mass spectrometry. The molecular weights and amino acid sequences of the peptides were confirmed by primary and secondary spectra, respectively. The results indicate that the SLA-2-(G4S)3-beta(2)m was 41.6kDa, and its alpha-helix, beta-sheet, turn, and random coil by CD estimation were 78 aa, 149 aa, 67 aa, and 93 aa, respectively. SLA-2-(G4S)3-beta(2)m protein was able to bind the nonameric peptides derived from the FMDV VP1 region: 26-34 (RRQHTDVSF) and 157-165 (RTLPTSFNY). The experimental system demonstrated that the reconstructed SLA-2-(G4S)3-beta(2)m protein complex can be used to identify nonameric peptides, including T-cell epitopes in swine.

Extensive analysis of different allelelic structures of the chicken BF2 and beta2m proteins.

No information is available to date on the different allelelic structures of the chicken MHC class I (BF2) and beta2m proteins. To elucidate the structure, new allelic beta2m and five different BF2 genes were expressed solubly and purified in a pMAL-p2X/E. coli TB1 system. The 2D structure was detected by circular dichroism (CD) spectroscopy, and the 3D structures of their peptide-binding domain (PBD) were analyzed by homology modeling. The sequence lengths of the alpha-helix, beta-sheet, turn, and random coil in the five BF2 proteins were 69-73 aa, 67-72 aa, 35-37 aa, and 94-98 aa, respectively. The new beta2m protein displayed a typical beta-sheet. Homology modeling of the different BF2 and beta2m proteins demonstrated similarities to the structure of human and rat MHC class I proteins. The 3D structure, however, revealed that the BF2 and beta2m structures were unique. The correct refolding of recombinant BF2 and beta2m proteins might be a powerful tool to further detect antigenic peptides.