Chemoinformatic-guided engineering of polyketide synthases

Polyketide synthase (PKS) engineering is an attractive method to generate new molecules such as commodity, fine and specialty chemicals. A central challenge in PKS design is replacing a partially reductive module with a fully reductive module through a reductive loop exchange, thereby generating a saturated β-carbon. In this work, we sought to establish an engineering strategy for reductive loop exchanges based on chemoinformatics, a field traditionally used in drug discovery. We first introduced a set of donor reductive loops of diverse genetic origin and chemical substrate structures into the first extension module of the lipomycin PKS (LipPKS1). These results demonstrated that chemical similarity between the substrate of the donor loops and recipient LipPKS1 correlated with product titers. Consequently, we identified donor loops with substrates chemically similar to LipPKS1 for further reductive loop exchanges, and we observed a statistically significant correlation with production. Reductive loops with the highest chemical similarity resulted in production of branched, short-chain fatty acids reaching a titer of 165 mg/L in Streptomyces albus J1074. Collectively, our work formulizes a new chemoinformatic paradigm for de novo PKS biosynthesis which may accelerate the production of valuable bioproducts

Chemoinformatic-Guided Engineering of Polyketide Synthases.

Polyketide synthase (PKS) engineering is an attractive method to generate new molecules such as commodity, fine and specialty chemicals. A significant challenge is re-engineering a partially reductive PKS module to produce a saturated β-carbon through a reductive loop (RL) exchange. In this work, we sought to establish that chemoinformatics, a field traditionally used in drug discovery, offers a viable strategy for RL exchanges. We first introduced a set of donor RLs of diverse genetic origin and chemical substrates  into the first extension module of the lipomycin PKS (LipPKS1). Product titers of these engineered unimodular PKSs correlated with chemical structure similarity between the substrate of the donor RLs and recipient LipPKS1, reaching a titer of 165 mg/L of short-chain fatty acids produced by the host Streptomyces albus J1074. Expanding this method to larger intermediates that require bimodular communication, we introduced RLs of divergent chemosimilarity into LipPKS2 and determined triketide lactone production. Collectively, we observed a statistically significant correlation between atom pair chemosimilarity and production, establishing a new chemoinformatic method that may aid in the engineering of PKSs to produce desired, unnatural products

Inhibition of Hedgehog Signaling Decreases Proliferation and Clonogenicity of Human Mesenchymal Stem Cells

Human mesenchymal stem cells (hMSC) have the ability to differentiate into osteoblasts, adipocytes and chondrocytes. We have previously shown that hMSC were endowed with a basal level of Hedgehog signaling that decreased after differentiation of these cells. Since hMSC differentiation is associated with growth-arrest we investigated the function of Hh signaling on cell proliferation. Here, we show that inhibition of Hh signaling, using the classical inhibitor cyclopamine, or a siRNA directed against Gli-2, leads to a decrease in hMSC proliferation. This phenomenon is not linked to apoptosis but to a block of the cells in the G0/G1 phases of the cell cycle. At the molecular level, it is associated with an increase in the active form of pRB, and a decrease in cyclin A expression and MAP kinase phosphorylation. Inhibition of Hh signaling is also associated with a decrease in the ability of the cells to form clones. By contrast, inhibition of Hh signaling during hMSC proliferation does not affect their ability to differentiate. This study demonstrates that hMSC are endowed with a basal Hedgehog signaling activity that is necessary for efficient proliferation and clonogenicity of hMSC. This observation unravels an unexpected new function for Hedgehog signaling in the regulation of human mesenchymal stem cells and highlights the critical function of this morphogen in hMSC biology

Estrategias de Afrontamiento de Padres de Niños con Secuelas de Quemaduras Visibles

La presente investigación tuvo por objeto relacionar las estrategias de afrontamiento de padres de niños quemados con los niveles de ansiedad presentados por sus hijos. Para ello, se utilizó una metodología cuantitativa y un diseño de tipo descriptivo correlacional. La muestra estuvo conformada por 49 niños (as) y sus padres que los acompañaban en su tratamiento en COANIQUEM. Los instrumentos utilizados fueron el Inventario de Ansiedad Estadorasgo para Niños de Spielberger y el Cuestionario de Modos de Afrontamiento de Lazarus y Folkman. Los resultados señalan que las estrategias de afrontamiento Autocontrol, Reinterpretación positiva, Resolución planificada y Aceptación de la responsabilidad correlacionan significativamente con bajos niveles de ansiedad en los niños quemados

Estrategias de Afrontamiento de Padres de Niños con Secuelas de Quemaduras Visibles

This research was aimed at relating the coping strategies developed by parents ofchildren suffering from burn injuries and the levels of anxiety presented by thechildren themselves. For this purpose, a quantitative methodology and a design ofthe descriptive correlacional type were used.The sample consisted of 49 children, and their accompanying parents, attendingtreatment at COANIQUEM. The instruments used were Spielberger’s Inventory ofAnxiety State – feature for Children and the Lazarus and Folkman’s Ways of CopingQuestionnaire. The results indicate that the strategies coming of selfcontrol, PositiveReinterpretation, Planned Resolution and Acceptance of Responsibility correlatesignificantly with low levels of anxiety in burned children.La presente investigación tuvo por objeto relacionar las estrategias de afrontamiento de padres de niños quemados con los niveles de ansiedad presentados por sus hijos. Para ello, se utilizó una metodología cuantitativa y un diseño de tipo descriptivo–correlacional.La muestra estuvo conformada por 49 niños (as) y sus padres que los acompañaban en su tratamiento en COANIQUEM. Los instrumentos utilizados fueron el Inventario de Ansiedad Estado–rasgo para Niños de Spielberger y el Cuestionario de Modos de Afrontamiento de Lazarus y Folkman.Los resultados señalan que las estrategias de afrontamiento Autocontrol, Reinterpretación positiva, Resolución planificada y Aceptación de la responsabilidadcorrelacionan significativamente con bajos niveles de ansiedad en los niños quemados

Codex Fejérváry-Mayer : an old Mexican picture manuscript in the Liverpool free public museums (12014/M) /

The pictures of the Codex are reproduced in red outline drawings on 22 plates. The facsimile of the Codex in colors forms a separate publication "Codex Fejérváry-Mayer: manuscript mexicain pré-colombien ... publié ... par le duc de Loubat. Paris, 1901.""English edition by A.H. Keane." Published also in German with title: "Codex Fejérváry-Mayer: eine altmexikanische Bilderschrift ... Erläutert von dr. Eduard Seler. Berlin, 1901."Includes index.Mode of access: Internet

New KCNN4 Variants Associated With Anemia: Stomatocytosis Without Erythrocyte Dehydration

International audienceThe K + channel activated by the Ca 2+ , KCNN4, has been shown to contribute to red blood cell dehydration in the rare hereditary hemolytic anemia, the dehydrated hereditary stomatocytosis. We report two de novo mutations on KCNN4 , We reported two de novo mutations on KCNN4 , V222L and H340N, characterized at the molecular, cellular and clinical levels. Whereas both mutations were shown to increase the calcium sensitivity of the K + channel, leading to channel opening for lower calcium concentrations compared to WT KCNN4 channel, there was no obvious red blood cell dehydration in patients carrying one or the other mutation. The clinical phenotype was greatly different between carriers of the mutated gene ranging from severe anemia for one patient to a single episode of anemia for the other patient or no documented sign of anemia for the parents who also carried the mutation. These data compared to already published KCNN4 mutations question the role of KCNN4 gain-of-function mutations in hydration status and viability of red blood cells in bloodstream