953 research outputs found
Extraction and Partial Characterization of Proteolytic Activities from the Cell Surface of Lactobacillus helveticus Zuc2
Abstract Proteolytic activities were extracted from a dairy Lactobacillus helveticus strain and partially characterized. A first cell envelope proteinase (CEP) was extracted using a high ionic strength buffer, both in the presence and in the absence of Ca 2+ . Moreover, cell treatment by 5 M LiCl allowed for the selective removal of the S-layer protein and CEP, suggesting an enzyme ionic linkage to the cell envelope similar to that observed for the Slayer structure. The enzyme specificity against α s1 -CN (f1–23) showed unusual activity on the Lys 3 -His 4 bond compared with other proteinases of the same species. A second proteinase appeared to be linked to the cell membrane because it was extractable only after membrane disgregation by detergents. Its specificity against CN fractions and α s1 -CN (f1–23) was different from that of the first CEP; moreover, the measured activity was lower than that of CEP
Modelling of a Gerotor pump including the evaluation of the micro-movements of the external gear
Produção agrícola mundial: o potencial do Brasil.
O objetivo deste trabalho é analisar a evolução mundial da produção e da demanda de alimentos, madeira e fibras e as possibilidades do Brasil participar de parcela maior no comércio mundial do agronegócio nos próximos anos. Ao longo dos últimos quarenta anos a oferta mundial aumentou substancialmente em função do uso de novas tecnologias de produção relacionadas aos chamados insumos modernos (sementes melhoradas, calcário, produtos fitossanitários, irrigação, maquinaria agrícola mais desenvolvida), maior profissionalização dos produtores, melhores canais de comercialização e apoio mais intenso dos governos e foi suficiente para atender a demanda mundial
Infertility and hypergonadotropic hypogonadism as first evidence of hereditary apolipoprotein A-I amyloidosis
Purpose: We report that primary infertility and hypergonadotropic hypogonadism in young patients may be caused by testicular amyloidosis and it is associated with the presence of a mutation in the apoA-I gene, resulting in the replacement of proline for leucine at residue 75 of the protein.
Materials and Methods: Ten patients presenting with infertility, gynecomastia, decreased libido, erectile dysfunction or a family history of amyloidosis underwent clinical evaluation, hormone assays, semen analysis, ultrasonographic investigation of the testicles, testicular biopsy and DNA sequencing of the apoA-I gene.
Results: All patients showed azoospermia and 9 had increased testicular volume. Massive amyloid deposition was observed in all testicular biopsies and the apoA-I mutation of replacement of proline for leucine at residue 75 of the protein was noted. Five patients showed hypergonadotropic hypogonadism and 5 had normal testosterone values with high gonadotropin levels.
Conclusions: Nonobstructive azoospermia and macro-orchidism with or without hypogonadism may be caused by hereditary apoA-I amyloidosis in young patients. Testicular amyloidosis can be the first manifestation of this systemic disease. Specific staining for amyloid deposits and genetic analysis of apoA-I mutations are recommended in young, infertile patients with macro-orchidism. Finally, surveillance in asymptomatic mutation carriers is suggested to evaluate the opportunity to implement sperm retrieval and start androgen replacement therapy when necessary
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