ABSTRACT
The number of foodborne intoxications caused by emetic Bacillus cereus isolates has increased significantly. As such, rapid and reliable methods to identify emetic strains appear to be clinically relevant. In this study, intact cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to differentiate emetic and non-emetic bacilli. The phyloproteomic clustering of 34 B. cereus emetic and 88 non-emetic isolates classified as B. cereus, Bacillus thuringiensis, Bacillus weihenstephanensis, and Bacillus mycoides, showed (i) a clear separation of both groups at a similarity level of 43%, and (ii) a high relatedness among the emetic isolates (similarity of 78%). Specifically, 83 mass peak classes were recognized in the spectral window range between m/z 4000 and 12 000 that were tentatively assigned to 41 protein variants based on a bioinformatic approach. Mass variation between the emetic and the non-emetic subsets was recorded for 27 of them, including ten ribosomal subunit proteins, for which inter-strain polymorphism was confirmed by gene sequencing. Additional peaks were assigned to other proteins such as small acid soluble proteins, cold shock proteins and hypothetical proteins, e.g., carbohydrate kinase. Moreover, the results were supported by in silico analysis of the biomarkers in 259 members of B. cereus group, including Bacillus anthracis, based on their whole-genome sequences. In conclusion, the proteomic profiling by MALDI-TOF MS is a promising and rapid method for pre-screening B. cereus to identify medically relevant isolates and for epidemiologic purposes.
Subject(s)
Bacillus cereus/isolation & purification , Bacterial Typing Techniques/methods , Emetics/isolation & purification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Bacillus/isolation & purification , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Polymorphism, Genetic , Proteomics/methods , Sequence Analysis, DNASubject(s)
Cathartics/adverse effects , Emetics/adverse effects , Gastric Lavage/methods , Adult , Asphyxia/chemically induced , Cathartics/isolation & purification , Child , Emetics/isolation & purification , Humans , Ipecac/adverse effects , Pneumonia, Aspiration/chemically induced , Vomiting/chemically induced , Vomiting/complicationsABSTRACT
The lipophilic toxin, cereulide, emitted by emetic food poisoning causing strains of Bacillus cereus, is a powerful mitochondria toxin. It is highly lipophilic and rapidly absorbed from the gut into the bloodstream. We tested how this toxin influences natural killer (NK) cells, which are important effectors in defence against infections and malignancy. Cereulide inhibited cytotoxicity and cytokine production of natural killer cells, caused swelling of natural killer cell mitochondria, and eventually induced natural killer cell apoptosis. The suppressive effect on cytotoxicity was fast and toxic concentration low, 20-30 microg/l. As the emesis causing concentration of cereulide is around 10 microg/kg of total body mass, our results suggest that emesis causing or even lower doses of cereulide may also have a systemic natural killer cell suppressive effect.
Subject(s)
Bacterial Toxins/pharmacology , Depsipeptides , Killer Cells, Natural/drug effects , Peptides, Cyclic/pharmacology , Apoptosis , Bacillus cereus , Bacterial Toxins/isolation & purification , Bacterial Toxins/toxicity , Cells, Cultured , Cytokines/pharmacology , Cytotoxicity Tests, Immunologic , Dose-Response Relationship, Drug , Emetics/isolation & purification , Emetics/pharmacology , Emetics/toxicity , Humans , Interferon-gamma/biosynthesis , Interleukin-1/biosynthesis , Killer Cells, Natural/immunology , Killer Cells, Natural/ultrastructure , Kinetics , Membrane Potentials/drug effects , Mitochondria/drug effects , Mitochondria/physiology , Mitochondria/ultrastructure , Monocytes/drug effects , Monocytes/immunology , Peptides, Cyclic/isolation & purification , Peptides, Cyclic/toxicity , T-Lymphocytes/drug effects , T-Lymphocytes/immunology , Tumor Cells, CulturedABSTRACT
From the dried roots of Cephaelis acuminata, five tetrahydroisoquinoline-monoterpene glycosides, 2-O-beta-D-glucopyranosyldemethylalangiside, demethylisoalangiside, 6"-O-beta-D-glucopyranosylipecoside, 6"-O-alpha-D-glucopyranosylipecoside and (4R)-4-hydroxyipecoside, were isolated. The structures of these glycosides were determined by spectroscopic and chemical means.
Subject(s)
Alkaloids/isolation & purification , Cephaelis/chemistry , Glucosides/isolation & purification , Isoquinolines/isolation & purification , Monoterpenes , Alkaloids/chemistry , Emetics/chemistry , Emetics/isolation & purification , Glucosides/chemistry , Isoquinolines/chemistry , Plant Roots/chemistryABSTRACT
To study the correlation between emetic toxin and HEp-2 vacuole activity produced by Bacillus cereus isolated from an outbreak of vomiting-type food poisoning, some properties and emetic activities of both purified HEp-2 factor (cereulide) and partially purified factor to rhesus monkeys were determined. The results indicate that both cereulide and partially purified factor were very stable to digestion with proteolytic enzymes, different pH, and heating. Vomiting was induced in the rhesus monkeys orally administered with both substances. From these findings, cereulide (or HEp-2 vacuole factor) is strongly suggested to be an emetic toxin itself.
Subject(s)
Bacillus cereus/chemistry , Bacterial Toxins/toxicity , Depsipeptides , Emetics/toxicity , Enterotoxins/toxicity , Peptides, Cyclic/toxicity , Administration, Oral , Animals , Bacterial Toxins/administration & dosage , Bacterial Toxins/isolation & purification , Capillary Permeability , Cell Line , Emetics/administration & dosage , Emetics/isolation & purification , Enterotoxins/administration & dosage , Enterotoxins/isolation & purification , Hemolysis , Hot Temperature , Hydrogen-Ion Concentration , Macaca mulatta , Mice , Pepsin A , Peptides, Cyclic/administration & dosage , Peptides, Cyclic/isolation & purification , Trypsin , Vacuoles/drug effectsABSTRACT
The underground caudex of the cycad Stangeria eriopus is used extensively by several ethnic groups in South Africa, mainly as an ingredient in magical potions but also as an emetic. An assessment of two main outlets showed that 3410 plants were sold in the month of July 1992; continued usage of this material now threatens the remaining plant populations. A proximate analysis of the caudex material gives high carbohydrate content with only small percentages of fat, protein, fibre and ash. An unusually high content of sodium sulphate may explain the efficacy of Stangeria-containing preparations as an emetic. The phytosterols sitosterol and stigmasterol are present in a 4:1 ratio while the fatty acid component comprises palmitic, oleic, stearic and arachidic acids. Twelve amino acids were identified in the material, including the non-protein amino acids beta-alanine, gamma-aminobutyric acid and pyroglutamic acid. The candidate neurotoxin beta-N-methylamino-L-alanine could not be detected but cycasin is present at the levels of 0.17% and 0.21% in fresh and dry caudex material, respectively and appears to be accompanied by the related toxin, macrozamin.
