RESUMEN
All representatives of higher eukaryotes can probably differentially perceive nutrients and poisonous substances. Molecular mechanisms of transduction of taste information have been best studied for mammals and for the fruit fly Drosophila. Here, we consider receptor mechanisms and conjugated primary signal processes of stimulation of taste receptor cells by stimuli of various taste modalities.
Asunto(s)
Células Quimiorreceptoras/fisiología , Transducción de Señal/fisiología , Papilas Gustativas/fisiología , Umbral Gustativo/fisiología , Gusto/fisiología , Animales , Drosophila melanogaster/fisiología , Humanos , Activación del Canal Iónico/fisiología , Neuronas Aferentes/fisiologíaRESUMEN
Proteomic approaches have been used for detection and identification of cytochromes P450 from highly-purified membrane preparations of human liver. These included the protein separation by 2D- and/or 1D-electrophoresis and molecular scanning of a SDS-PAGE gel fragment in the range of 45-66 kD (this area corresponds molecular weights of cytochromes P450). The analysis of protein content was statistically evaluated by means of original 1D-ZOOMER software package which allowed to carry out processing of mass spectra mixture instead of individual mass spectra used by standard techniques. In the range of 45-66 kDa we identified 13 microsomal membrane proteins including 11 cytochromes P450, namely CYPs 1A2, 1B1, 2A6, 2E1, 2C8, 2C9, 2C10, 2D6, 3A4, 4A11, 4F2. The microsomal samples were characterized by the enzymatic assays using the marker substrates for CYP1A, 2B, 3A4, 2C and 2E1. The 7-methoxy- and 7-ethoxyresorufin-O-dealkylase activities (i.e. the marker activities for cytochromes P450 1A1/1A2, respectively) and the erythromycin-N-demethylase activity (i.e. the marker activity for cytochrome P450 3A4) are lowered in pathology compared to these activities in norm. At the same time the benzyloxyresorufin-O-debenzylase activity (which characterizes the total activity of CYP2B and CYP2C), the activities of CYP2E1 (methanol), 7-pentoxyresorufin-O-dealkylation (CYP2B), 7-ethoxy- and 7-methoxycoumarin-O-dealkylases (CYP2B1) did not change. On the basis of the results obtained efficiency of a combination proteomic and biochemical analyses for inventory cytochromes P450 and revealing of their level expression is shown, and opportunities of mass spectrometry for a quantitative estimation of proteins are discussed.
Asunto(s)
Sistema Enzimático del Citocromo P-450/metabolismo , Microsomas Hepáticos/enzimología , Citocromos b5/metabolismo , Electroforesis en Gel Bidimensional , Humanos , NADPH-Ferrihemoproteína Reductasa/metabolismo , Proteómica , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The human gene-engineering gamma-interferon agent gammaferon (GF) is demonstrated to lower the level of chromosomal aberrations and release of cyclophosphamide-induced micronuclei in murine bone marrow cells. A model is suggested for regulating the ratio of single to multiple chromosomal aberrations induced by cyclophosphamide by altering the antioxidative status of the body. With this model, it was shown that the antimutagenic effects of GF were caused by two factors: the antioxidative effect of the corresponding placebo and the unknown (but none antioxidative) effect of gamma-interferon itself. Erythrocytic resistance to in vitro oxidative disturbance in the Fe2+/system was used as an integral measure of the body's antioxidative status.
Asunto(s)
Antimutagênicos/farmacología , Interferón gamma/farmacología , Animales , Ácido Ascórbico/farmacología , Médula Ósea/efectos de los fármacos , Células de la Médula Ósea , Distribución de Chi-Cuadrado , Aberraciones Cromosómicas , Ciclofosfamida/farmacología , Hemólisis/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Proteínas Recombinantes , Especificidad de la EspecieRESUMEN
Electrophysiological and morphological studies of an identified giant neurone of the snail Helix pomatia showed that the neurone PPa4 possesses a large receptive field and axones entering peripheric nerves. It is suggested that this neurone is an output integrative link of the mollusc's CNS. Through various types of spike activity PPa4 may exert a tonic or a phasic effect on neurones of the peripheric nervous system or a direct influence on effector organs of the mantle and pneumostome.