Tailoring the Specificity of a Plant Cystatin toward Herbivorous Insect Digestive Cysteine Proteases by Single Mutations at Positively Selected Amino Acid Sites1[OA]

Plant cystatins, similar to other defense proteins, include hypervariable, positively selected amino acid sites presumably impacting their biological activity. Using 29 single mutants of the eighth domain of tomato (Solanum lycopersicum) multicystatin, SlCYS8, we assessed here the potential of site-directed mutagenesis at positively selected amino acid sites to generate cystatin variants with improved inhibitory potency and specificity toward herbivorous insect digestive cysteine (Cys) proteases. Compared to SlCYS8, several mutants (22 out of 29) exhibited either improved or lowered potency against different model Cys proteases, strongly suggesting the potential of positively selected amino acids as target sites to modulate the inhibitory specificity of the cystatin toward Cys proteases of agronomic significance. Accordingly, mutations at positively selected sites strongly influenced the inhibitory potency of SlCYS8 against digestive Cys proteases of the insect herbivore Colorado potato beetle (Leptinotarsa decemlineata). In particular, several variants exhibited improved potency against both cystatin-sensitive and cystatin-insensitive digestive Cys proteases of this insect. Of these, some variants also showed weaker activity against leaf Cys proteases of the host plant (potato [Solanum tuberosum]) and against a major digestive Cys protease of the two-spotted stinkbug Perillus bioculatus, an insect predator of Colorado potato beetle showing potential for biological control. Overall, these observations suggest the usefulness of site-directed mutagenesis at positively selected amino acid sites for the engineering of recombinant cystatins with both improved inhibitory potency toward the digestive proteases of target herbivores and weaker potency against nontarget Cys proteases in the host plant or the environment

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O 'homem de invenções' e as 'recompensas nacionais': notas sobre H. Florence e L. J. M. Daguerre

This paper presents and contextualizes mail never published before found in the Centre des Archives Diplomatiques de Nantes (France) about the invention of the "polygraphy" by the Frenchman Antoine Hercule Romuald Florence (1804-1879). In 1831, Florence was living in the village of São Carlos, Brazil, nowadays a city called Campinas, when he forwarded to the Ministry of Interior of France a request for a reward for having developed a multifunctional printing process. He never received any answer from the French government. Nevertheless, he dedicated the rest of his life to other inventions and experiments, among them photography. He left as legacy reports on such initiatives and on his frustration for not being recognized in his home country as the first one to conceive them. Celebrated in his time as the inventor of the daguerreotype, the first photographic process known worldwide, Louis Jacques Mandé Daguerre (1787-1851) also faced criticism in his home country, and only recently started being redeemed by French historiography. Florence, for his turn, is recognized nowadays in Brazil and abroad, as one of the several inventors of photographic processes, along with Daguerre himself. The life stories and biographic accounts of Florence and Daguerre give us an opportunity to compare sociability networks, valorization strategies and ways of recognition of two of 19th century "men of inventions" which lived in very different cultural contexts but, at the same time, interconnected