-
Revista Clínica Española 10/2010; 210(9):481-2. · 2.01 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation.
Antonie van Leeuwenhoek 10/2004; 86(3):283-5. · 2.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez''s, the Prestige''s spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens, a bacterium promising for bioremediation.
Antonie van Leeuwenhoek 09/2004; 86(3):283-285. · 2.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The phase behaviour of the lipopolysaccharide lipid moiety, free lipid A, of Salmonella typhimurium, S. minnesota, Shigella flexneri, Escherichia coliand, especially, Brucella melitensis and B. abortus has been investigated by applying differential scanning calorimetry. Working with samples in the solid state and a N2 atmosphere, we have obtained results that could lead to a redefinition of the main temperature of the gel ⇐ liquid crystalline transition of the hydrocarbon chains to between 30 and 41°C (instead of around 45°C).The fluidity of the acyl chains and the lyotropic behaviour in the β ⇐ α melting transition, which are important parameters with respect to the expression of biological activities, are also discussed for the lipids A from the different bacterial species.
Thermochimica Acta 208:139-145. · 1.80 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present work constitutes an entirely novel contribution in the scope of microbiology and especially in taxonomy, introducing thermolysis curves as a rapid method of characterization of fungal polysaccharides and bacterial lipopolysaccharides. The thermal analysis techniques applied were thermogravimetry and derivative thermogravimetry (TG-DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Each thermogram of a sample is represented by one or a few temperatures and, in DSC, by complementary enthalpy data. The temperatures of the thermograms from structurally unknown polysaccharides are compared with those used as references, and thus, information on their composition, linkage types, and anomeric configuration can be deduced. The situation is more complicated for bacterial lipopolysaccharides, but in whatever mode, a structural estimation is always possible. In the course of the development and validation of the thermal method, structural findings on relative stabilities of linkage types (valuable in carbohydrate research) have been recognized and are therefore also described in this work.
Biotechnology Progress 7(6):526-33. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Differential scanning calorimetry (DSC) was used to investigate the thermal stability and behaviour of the lipopolysaccharides (LPS) of the outer membrane of Gram-negative bacteria and their lipid portion. DSC curves of LPS show thermal features between 200 and 129 degrees C (depolymerization) and between -13 and -36 degrees C (cooling phase transition). Both effects were related to the relative strength of the linkage types in the O-chain structure and to their capacity for intermolecular hydrogen bonding. DSC curves of lipids A show endotherm peaks between 40 and 24 degrees C, around 15 degrees C and between -23 and -4 degrees C. Based on these effects, strong differences in thermal behaviour can be observed between that of Brucella and Vibrio cholerae on the one hand, and that of Escherichia coli and Shigella flexneri on the other. Fluidity of the acyl chains and lyotropism, which are important parameters in expression of biological activities, are discussed using the above data. To explain some properties, fluidity could be related to the temperature of the gel<==>liquid crystalline (beta<==>alpha) phase transition, which occurs at physiological temperature. Nevertheless, fluidity could be related to temperature of the previous thermal effect (between 6 and 20 degrees C), for which a softening or partial melting of the sample has been evidenced. The thermal effect measured between -23 degrees C and -4 degrees C indicates a greatly reduced water concentration of lipid A from Brucella, thus explaining its early fusion process and its activity by means of hydrophobic interactions.
Research in Microbiology 144(9):729-40. · 2.76 Impact Factor
