Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

A novel calmodulin-binding protein functions as a negative regulator of osmotic stress tolerance in Arabidopsis thaliana seedlings.

Abstract: A clone for a novel Arabidopsisthaliana calmodulin (CaM)-binding protein of 25 kDa (AtCaMBP25) has been isolated by using a radiolabelled CaM probe to screen a cDNA expression library derived from A. thaliana cell suspension cultures challenged with osmotic stress. The deduced amino acid sequence of AtCaMBP25 contains putative nuclear localization sequences and shares significant degree of similarity with hypothetical plant proteins only. Fusion of the AtCaMBP25 coding sequence to reporter genes targets the hybrid protein to the nucleus. Bacterially expressed AtCaMBP25 binds, in a calcium-dependent manner, to a canonical CaM but not to a less conserved isoform of the calcium sensor. AtCaMBP25 is encoded by a single-copy gene, whose expression is induced in Arabidopsis seedlings exposed to dehydration, low temperature or high salinity. Transgenic plants overexpressing AtCaMBP25 exhibits an increased sensitivity to both ionic (NaCl) and non-ionic (mannitol) osmotic stress during seed germination and seedling growth. By contrast, transgenic lines expressing antisense AtCaMBP25 are significantly more tolerant to mannitol and NaCl stresses than the wild type. Thus, the AtCaMBP25 gene functions as a negative effector of osmotic stress tolerance and likely participates in stress signal transduction pathways.

In Situ Raman Spectroscopy Study of Oxidation of Double- and Single-Wall Carbon Nanotubes

Abstract: In situ Raman spectroscopy allows for a detailed and time-resolved investigation of the kinetics of complex physical or chemical processes. Oxidation has become a frequently used method for the removal of disordered carbon species from carbon nanotubes. Oxidation, however, can also induce damage to the tubes and destroy most of the sample. We conducted an in situ Raman spectroscopy study of the oxidation of double- and single-walled carbon nanotubes (DWCNT and SWCNT) under isothermal and nonisothermal conditions to identify the temperature range in which the oxidation of amorphous carbon occurs without any changes with respect to the tubes and their structure. In situ Raman spectroscopy analysis of the oxidation of DWCNTs showed a decrease in the intensity of the D band starting around 370 °C, followed by complete D band elimination at 440 °C. Oxidation studies of SWCNTs showed a similar decrease in the D band intensity, but the D band was not completely eliminated. Furthermore, in situ measurements allow...