RESUMO
Clostridioides difficile (C. difficile) is an opportunistic anaerobic bacterium that causes severe diseases of the digestive tract of humans and animals. One of the possible methods of preventing C. difficile infection is to develop a vaccine. The most promising candidates for vaccine antigens are the proteins involved in the adhesion phenomena. Among them, the FliC and FliD are considered to be suitable candidates. In this paper, the FliC and FliD protein polypeptide epitopes were mapped in silico and by using PEPSCAN procedure. We identified four promising epitopes: 117QRMRTLS123, 205MSKAG209 of FliC and 226NKVAS230, 306TTKKPKD312 of FliD protein. We showed that 117QRMRTLS123 sequence is not only located in TLR5-binding and activating region, as previously shown, but forms an epitope recognized by C. difficile-infected patients' antibodies. 205MSKAG209 is a C. difficile-unique, immunogenic sequence that forms an exposed epitope on the polymerized flagella structure which makes it a suitable vaccine antigen. 226NKVAS230 and 306TTKKPKD312 are well exposed and possess potential protective properties according to VaxiJen analysis. Our results open the possibility to use these epitopes as suitable anti-C. difficile vaccine antigens.
Assuntos
Clostridioides difficile/imunologia , Infecções por Clostridium/diagnóstico , Flagelos/imunologia , Sequência de Aminoácidos/genética , Animais , Anticorpos Antibacterianos/imunologia , Proteínas de Bactérias/imunologia , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Clostridioides/genética , Clostridioides/imunologia , Clostridioides difficile/patogenicidade , Infecções por Clostridium/imunologia , Epitopos/imunologia , Flagelina/imunologia , Humanos , Coelhos , Alinhamento de Sequência/métodosRESUMO
BACKGROUND: The aim of the current study was to investigate whether the Basidiomycetes fungus Lentinula edodes can biosynthesize Se-methyl-seleno-l-cysteine, a seleno-amino acid with strong anticancer activity, and to optimize the culture conditions for its biosynthesis. We hypothesize that preparations obtained from Se-methyl-seleno-l-cysteine-enriched mycelia from this medicinal mushroom would possess stronger cancer-preventive properties than current preparations. RESULTS: By optimizing the concentration of selenium in the culture medium, we increased the mycelial concentration of Se-methyl-seleno-l-cysteine from essentially non-detectable levels to 120 µg/g dry weight. Significantly elevated levels of this amino acid also correlated with significant (twofold) inhibition of mycelial growth. Increases in the concentration of mycelial Se-methyl-seleno-l-cysteine appeared to be highly correlated with the enhanced biosynthesis of selenomethionine and total selenium content in mycelium. CONCLUSIONS: We have demonstrated that in L. edodes, enhanced biosynthesis of this non-protein amino acid eliminates excess selenium.
