RESUMEN
Biofilms are communities of surface-attached microbial cells that resist environmental stresses. In this study, we found that low concentrations of ethanol increase biofilm formation in Pseudomonas aeruginosa PAO1 but not in a mutant of it lacking both Psl and Pel exopolysaccharides. Low concentrations of ethanol also increased pellicle formation at the air-liquid interface.
Asunto(s)
Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Etanol/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Relación Dosis-Respuesta a Droga , Polisacáridos Bacterianos/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismoRESUMEN
Many Gram-negative bacteria release membrane vesicles (MVs), but their phospholipid properties are poorly understood. Phosphatidylglycerol was present at high levels in MVs derived from Pseudomonas aeruginosa, but not in the cellular outer membrane. The ratio of stearic acid in MVs was high compared to that in the cellular outer membrane. These findings suggest that membrane rigidity is associated with MV biogenesis.
Asunto(s)
Ácidos Grasos/análisis , Fosfolípidos/análisis , Pseudomonas aeruginosa/química , Proteínas de la Membrana Bacteriana Externa/análisis , Membrana Celular/química , Membrana Celular/metabolismo , Cromatografía en Capa Delgada , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/metabolismoRESUMEN
OBJECTIVES: Several studies have reported that the secretory immunoglobulin A (S-IgA) concentration in saliva is an indicator of psychological stress. The aim of this study was to clarify the relationship between S-IgA and the stress from academic examinations. METHODS: S-IgA levels in 10 medical student volunteers from the second year course between May 4 and July 13, 2000 were examined using the ELISA method. RESULTS: There was a tendency for S-IgA in saliva to be higher on the day before academic examinations and during them, and lower on the days between these examinations. CONCLUSIONS: It may be possible to use this measurement to monitor psychological stress in students and workers.
