Identification of a novel protein in the genome sequences of Leptospira interrogans with the ability to interact with host's components

Background Leptospirosis is an infectious disease that affects humans and animals worldwide. The etiological agents of this disease are the pathogenic species of the genus Leptospira. The mechanisms involved in the leptospiral pathogenesis are not full understood. The elucidation of novel mediators of host-pathogen interaction is important in the detection of virulence factors involved in the pathogenesis of leptospirosis. Objective This work focused on identification and characterization of a hypothetical protein of Leptospira encoded by the gene LIC10920. Methods The protein of unknown function was predicted to be surface exposed. Therefore, the LIC10920 gene was cloned and the protein expressed in Escherichia coli BL21 (DE3) Star pLysS strain. The recombinant protein was purified by metal affinity chromatography and evaluated with leptospirosis human serum samples. The interaction with host components was also performed. Results The recombinant protein was recognized by antibodies present in leptopsirosis human serum, suggesting its expression during infection. Immunofluorescence and intact bacteria assays indicated that the bacterial protein is surface-exposed. The recombinant protein interacted with human laminin, in a dose-dependent and saturable manner and was named Lsa24.9, for Leptospiral surface adhesin, followed by its molecular mass. Lsa24.9 also binds plasminogen (PLG) in a dose-dependent and saturable fashion, fulfilling receptor ligand interaction. Moreover, Lsa24.9 has the ability to acquire PLG from normal human serum, exhibiting similar profile as observed with the human purified component. PLG bound Lsa24.9 was able of generating plasmin, which could increase the proteolytic power of the bacteria. Conclusions This novel leptospiral protein may function as an adhesin at the colonization steps and may help the invasion process by plasmin generation at the bacterial cell surface.

Identification of a novel protein in the genome sequences of Leptospira interrogans with the ability to interact with host's components

Background Leptospirosis is an infectious disease that affects humans and animals worldwide. The etiological agents of this disease are the pathogenic species of the genus Leptospira. The mechanisms involved in the leptospiral pathogenesis are not full understood. The elucidation of novel mediators of host-pathogen interaction is important in the detection of virulence factors involved in the pathogenesis of leptospirosis. Objective This work focused on identification and characterization of a hypothetical protein of Leptospira encoded by the gene LIC10920. Methods The protein of unknown function was predicted to be surface exposed. Therefore, the LIC10920 gene was cloned and the protein expressed in Escherichia coli BL21 (DE3) Star pLysS strain. The recombinant protein was purified by metal affinity chromatography and evaluated with leptospirosis human serum samples. The interaction with host components was also performed. Results The recombinant protein was recognized by antibodies present in leptopsirosis human serum, suggesting its expression during infection. Immunofluorescence and intact bacteria assays indicated that the bacterial protein is surface-exposed. The recombinant protein interacted with human laminin, in a dose-dependent and saturable manner and was named Lsa24.9, for Leptospiral surface adhesin, followed by its molecular mass. Lsa24.9 also binds plasminogen (PLG) in a dose-dependent and saturable fashion, fulfilling receptor ligand interaction. Moreover, Lsa24.9 has the ability to acquire PLG from normal human serum, exhibiting similar profile as observed with the human purified component. PLG bound Lsa24.9 was able of generating plasmin, which could increase the proteolytic power of the bacteria. Conclusions This novel leptospiral protein may function as an adhesin at the colonization steps and may help the invasion process by plasmin generation at the bacterial cell surface.

Quality evaluation of gnocchi pasta prepared with orange-fleshed sweet potato / Avaliação da qualidade de massas do tipo nhoque elaboradas com batata-doce de polpa alaranjada

Considering the increase of pasta market and the importance of orange-fleshed sweet potato (OFSP) nutritional value and economic aspects, this study aimed to evaluate the effect of the addiction of OFSP and potato starch on the physical characteristics of gnocchi pasta during cooking, as well as to determine the chemical and sensory characteristics of the best samples, analyzing them during storage. A central composite rotational 2nd order experimental design was employed to investigate the effects of adding 63.65% to 75.81% OFSP and 35.86% to 64.14% potato starch during the cooking of the pasta. The best treatments were analyzed for acceptability, chemical composition and behavior during storage. The addition of OFSP affected only the cooking time by causing an increase in this value. Moreover, it positively contributed to the acceptability of the product, especially the color, as well as to the increase of the fiber and ash contents. It is recommended to consume immediately after preparation. If storage is necessary, the refrigeration at 4°C is suggested, provided that packaging requirements are met, preferably vacuum packaging.

Frente ao crescente mercado de massas alimentícias e da importância da batata doce de polpa alaranjada (BDPA) por seu valor nutritivo e aspectos econômicos, este estudo teve como objetivo avaliar o efeito da adição de BDPA e fécula de batata nas características físicas de massas do tipo nhoque durante o cozimento, bem como determinar as características químicas e sensoriais das melhores amostras caracterizando-as durante seu armazenamento. Utilizou-se um delineamento central composto rotacional de 2ª ordem para investigar os efeitos da adição de 63,65% a 75,81% de BDPA e de 35,86% a 64,14% de fécula de batata durante a cocção das massas. Os melhores tratamentos foram analisados quanto a aceitabilidade, composição química e comportamento durante o armazenamento. A adição de BDPA nas massas de nhoque influenciou apenas no tempo de cozimento ocasionando aumento deste valor. Além disso, contribuiu positivamente para a aceitabilidade do produto, em especial à cor, bem como para o aumento dos teores de resíduo mineral e fibras. Recomenda-se que o consumo seja imediato, após o preparo. Sendo necessário o armazenamento, sugere-se que sejam mantidos sob refrigeração a 4°C, desde que sejam respeitadas as condições de embalagem, de preferência à vácuo.