Straight motion of half-integer topological defects in thin Fe-N magnetic films with stripe domains

International audienc

Flutuação de esporos de Plasmopara vitícola em cultivo protegido de videira.

o uso da cobertura plástica (CP) no cultivo de videiras pode apresentar vantagens no ganho em qualidade das uvas, protegendo çle prejuizos causados por granizos e doenças fúngicas. O mildio da videira (P/asmopaf'8 vilico/a) é a' doença fúngica com maior importância no que diz respeito à incidência e gastos com aplicações de fungicidas. A modificação microclimática que a CP pode exercer sobre o vinhedo, sobretudo pela eliminação da água livre sobre folhas e cachos, contribui para a diminuição de incidência e severidade de doenças fúngicas de forma geral.Resumo

Versatile vector suite for the extracytoplasmic production and purification of heterologous His-tagged proteins in Lactococcus lactis

Recent studies have shown that the Gram-positive bacterium Lactococcus lactis can be exploited for the expression of heterologous proteins; however, a versatile set of vectors suitable for inducible extracellular protein production and subsequent purification of the expressed proteins by immobilized metal affinity chromatography was so far lacking. Here we describe three novel vectors that, respectively, facilitate the nisin-inducible production of N- or C-terminally hexa-histidine (His(6))-tagged proteins in L. lactis. One of these vectors also encodes a tobacco etch virus (TEV) protease cleavage site allowing removal of the N-terminal His(6)-tag from expressed proteins. Successful application of the developed vectors for protein expression, purification and/or functional studies is exemplified with six different cell wall-bound or secreted proteins from Staphylococcus aureus. The results show that secretory production of S. aureus proteins is affected by the position, N- or C-terminal, of the His(6)-tag. This seems to be due to an influence of the His(6)-tag on protein stability. Intriguingly, the S. aureus IsdB protein, which is phosphorylated in S. aureus, was also found to be phosphorylated when heterologously produced in L. lactis, albeit not on the same Tyr residue. This implies that this particular post-translational protein modification is to some extent conserved in S. aureus and L. lactis. Altogether, we are confident that the present vector set combined with the L. lactis expression host has the potential to become a very useful tool in optimization of the expression, purification and functional analysis of extracytoplasmic bacterial proteins