Lon protease negatively affects GacA protein stability and expression of the Gac/Rsm signal transduction pathway in Pseudomonas protegens.

In Pseudomonas protegens CHA0 and other fluorescent pseudomonads, the Gac/Rsm signal transduction pathway controls secondary metabolism and suppression of fungal root pathogens via the expression of regulatory small RNAs (sRNAs). Because of its high cost, this pathway needs to be protected from overexpression and to be turned off in response to environmental stress such as the lack of nutrients. However, little is known about its underlying molecular mechanisms. In this study, we demonstrated that Lon protease, a member of the ATP-dependent protease family, negatively regulated the Gac/Rsm cascade. In a lon mutant, the steady-state levels and the stability of the GacA protein were significantly elevated at the end of exponential growth. As a consequence, the expression of the sRNAs RsmY and RsmZ and that of dependent physiological functions such as antibiotic production were significantly enhanced. Biocontrol of Pythium ultimum on cucumber roots required fewer lon mutant cells than wild-type cells. In starved cells, the loss of Lon function prolonged the half-life of the GacA protein. Thus, Lon protease is an important negative regulator of the Gac/Rsm signal transduction pathway in P. protegens.

Europa als ulls dels Annales (1093-1933)

During this first third of this century, the continent of Europe witnessed far-reaching territorial transformations in the nineteenth century model. To some extent, the setting wich had inspired the epistemological structure of the French regional school was being replaced by one in which -at least to externa1 appearances- the relationship between the physical environment and human activities was much less evident. The adaptation of the theoretical and methodological context to the new Europe seems to take the form of a non-lineal evolution, for in the latter years of the period examined, evolutionary tendencies indicate a return to the more classical model. In this way, the growing interest which the publication had shown in Atlantic Europe and topics of a more economic nature, was truncated. The traditional settings --especially the Mediterranean- came to the fore again and interest in rural societies was renewed. Likewise, the monographic studies which had demonstrated distinct functional objectives in the midtwenties, recovered elements of ecological explanation, and the search for the relationship between environment and society

Colombes, 25/4/20, présentation des équipes française et anglaise [de football militaire] à M. [Adolphe] Landry [ministre de la Marine] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 59050

4-4-20, Pantin [tribune où sont présents MM.] Jouhaux [et] Gémier [assistant au match de football Paris-Londres] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58724

Lexique de la langue de Bonaventure Des Périers ([Reprod.]) / Félix Frank, Adolphe Chenevière

Collection : Archives de la linguistique française ; 82

Conformité du langage françois avec le grec. édition accompagnée de notes et précédée d'un Essai sur la vie et les ouvrages de cet auteur ([Reprod.]) / par Henri Estienne... ; par Léon Feugère,...

Collection : Archives de la linguistique française ; 146

Du communisme / Adolphe Thiers

Collection : Archives de l'idéologie