Research on new fibrinolytic agents has been oriented towards the discovery of microbial proteases with plasmin-like activity, as alternative thrombolytic agents for thrombosis treatment. This study reports the characterization of an extracellular serine metalloprotease of approximately 56 kDa, with fibrinolytic and fibrinogenolytic activity, isolated from a S. marcescens strain obtained from the Amazon (CBAM 519). The enzyme showed optimum activity at pH 9 and temperature of 37 °C. Activity was reduced in the presence of Na+, Cu2+ and Fe2+ ions, and increased with Mn2⁺. The enzyme did not show hemolytic activity, nor did it activate plasminogen, but it effectively hydrolyzed fibrin and fibrinogen, rapidly degrading all fibrinogen chains Aα, Bβ and γ. Therefore, fibrinolysis was promoted only by the direct route, with a fast acting, potent fibrinolytic activity. Based on this, we expect the enzyme to be a protease of the plasmin type that directly degrades fibrin. These characteristics demonstrate great potential for its application in the treatment of thrombosis.

No abstract

Introduction Candida albicans is the yeast most commonly affecting the oral cavity, sometimes causing infection. However, several factors may be associated with the onset of candidiasis, which may be related not only to the hygiene and health of individuals, but also to the pathogenicity of these microorganisms. Objective To evaluate the virulence factors of Candida yeasts isolated from the oral mucosa of elderly people living in the “Comunidade Lago do Limão”, municipality of Iranduba, Amazonas state, Brazil. Material and method Testes were performed to assess the production of urease, proteinase, phospholipase and hemolysin. Statistical analysis used the Fisher's exact test and the Chi-squared test. Result Prevalence of non-albicans species was observed. As for virulence factors, all isolates were negative ureases, and there was prevalence of very strong proteinase production, whereas most isolates did not produce this enzyme in the phospholipase test. All yeasts analyzed presented hemolysin production, with grade IV hemolysis as the most prevalent. There was no statistically significant difference between the virulence of isolates from the oral cavity and the prostheses of the elderly analyzed. Conclusion Several virulence factors may present with high intensity in the presence of oral microbiota changes. In addition, non-albicans species present number of virulence factors similar to that of C. albicans, with high pathogenicity. This study allows a better analysis of candidiasis prevention strategies aiming to promote improvement in the health and quality of life for the elderly.

Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição 4.0 Internacional (CC BY 4.0). O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.