RÉSUMÉ
Paracoccidioides brasiliensis is a fungal pathogen of humans. To identify antigens from P. brasiliensis we fractionated a crude preparation of proteins from the fungus and detected the IgG reactive proteins by immunoblot assays of yeast cellular extracts with sera of patients with paracoccidioidomycosis (PCM). We identified and characterized six new antigens by amino acid sequencing and homology search analyses with other proteins deposited in a database. The newly characterized antigens were highly homologous to catalase, fructose-1,6-biphosphate aldolase (aldolase), glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase and triosephosphate isomerase from several sources. The characterized antigens presented preferential synthesis in yeast cells, the host fungus phase.
Sujet(s)
Antigènes fongiques/analyse , Protéines fongiques/analyse , Paracoccidioides/immunologie , Blastomycose sud-américaine/immunologie , Séquence d'acides aminés , Antigènes fongiques/composition chimique , Électrophorèse bidimensionnelle sur gel , Protéines fongiques/composition chimique , Humains , Immunotransfert , Immunoglobuline G/sang , Immunoglobuline G/immunologie , Données de séquences moléculaires , Similitude de séquences d'acides aminésRÉSUMÉ
Aqueous extracts of Paullinia cupana (guarana), a species that belongs to the Sapindaceae family, were analyzed for the presence of genotoxic activities in bacterial cells. The extracts of guarana were genotoxic as assessed by lysogenic induction in Escherichia coli and they were also able to induce mutagenesis in Salmonella typhimurium. Addition of S9 microsomal fraction, catalase, superoxide dismutase or thiourea counteracted the genotoxic activity of guarana, suggesting that oxygen reactive species play an essential role in the genotoxicity of aqueous guarana extracts. The genotoxic activity in the extracts was related to the presence of a molecular complex formed by caffeine and a flavonoid (catechin or epicatechin) in the presence of potassium.