ABSTRACT
Patch clamp electrophysiology is the main technique to study mechanosensitive ion channels (MSCs), however, conventional patch clamping is laborious and success and output depends on the skills of the operator. Even though automated patch systems solve these problems for other ion channels, they could not be applied to MSCs. Here, we report on activation and single channel analysis of a bacterial mechanosensitive ion channel using an automated patch clamp system. With the automated system, we could patch not only giant unilamellar liposomes but also giant Escherichia coli (E. coli) spheroplasts. The tension sensitivity and channel kinetics data obtained in the automated system were in good agreement with that obtained from the conventional patch clamp. The findings will pave the way to high throughput fundamental and drug screening studies on mechanosensitive ion channels.
Subject(s)
Automation, Laboratory/methods , Escherichia coli Proteins/metabolism , Ion Channels/metabolism , Patch-Clamp Techniques/methods , Escherichia coli/metabolism , Spheroplasts/metabolismABSTRACT
The flavoenzyme L-galactono-gamma-lactone dehydrogenase (GALDH) catalyzes the terminal step of vitamin C biosynthesis in plants. Little is known about the catalytic mechanism of GALDH and related aldonolactone oxidoreductases. Here we identified an essential Glu-Arg pair in the active site of GALDH from Arabidopsis thaliana. Glu386 and Arg388 variants show high K(m) values for L-galactono-1,4-lactone and low turnover rates. Arg388 is crucial for the stabilization of the anionic form of the reduced FAD cofactor. Glu386 is involved in productive substrate binding. The E386D variant has lost its specificity for L-galactono-1,4-lactone and shows the highest catalytic efficiency with L-gulono-1,4-lactone.
Subject(s)
Arabidopsis/metabolism , Arginine/metabolism , Glutamic Acid/metabolism , Lactones/metabolism , Oxidoreductases Acting on CH-CH Group Donors/metabolism , Sugar Acids/metabolism , Amino Acid Sequence , Amino Acid Substitution , Arabidopsis/genetics , Arginine/genetics , Catalytic Domain/genetics , Conserved Sequence , Glutamic Acid/genetics , Molecular Sequence Data , Oxidoreductases Acting on CH-CH Group Donors/geneticsABSTRACT
Se describe el diagnostico, tratamiento y evolucion de 25 casos de ninos que presentan cuadros de psicosis esquizomorfas, definiendo los criterios aplicados.Existe un especial enfasis en las correlaciones encontradas con epilepsia y dano cerebral.Se compara esta muestra con los hallazgos de la literatura, revisando asimismo las dificultades especiales que presentan los ninos con respecto a los adultos. Refuerza el concepto de sindrome esquizomorfo y la necesidad de precisar la etiologia en estos casos. Se muestra que la evolucion es, hasta el momento del seguimiento, levemente mas benigna que lo descrito por autores extranjeros para la esquizofrenia infantil advirtiendo que los resultados no son comparables, por cuanto la muestra es mas homogenea (excluye toda psicosis no esquizomorfa) y mas neurologica, debido a las fuentes de referencia
Subject(s)
Child , Adolescent , Humans , Male , Female , Brain Injuries , Epilepsy , Psychotic Disorders , SchizophreniaABSTRACT
We must take note of some useful tests for a correct and complete radiological valutation of vertebral scoliosis and kyphosis. Moreover, we have to consider analytically the relative indications and the diagnostic elements, that each of them might give. Technical inventions and practical criterions have also been taken into consideration since they limit the risks caused by being exposed to ionizing radiations.
