El estatuto del Obstaculo / The status of the Obstacle

En continuidad con la investigación que venimos realizando, abordamos la cuestión del obstáculo. El obstáculo es inherente tanto a la práctica como a la elaboración doctrinaria en psicoanálisis, hasta tal punto que lo podríamos llamar una teoría del obstáculo. El obstáculo es inherente a la problemática de la satisfacción pulsional, y se presenta a lo largo de toda la producción de Freud. Esta satisfacción, a su vez, adquiere diferentes nombres, y al final de la doctrina freudiana se va a presentar como el obstáculo a la conclusión de las curas y el advenimiento de nuevos analistas.

Cold-adapted yeasts as producers of cold-active polygalacturonases.

Eight cold-adapted, polygalacturonase-producing yeasts belonging to four species were isolated from frozen environmental samples in Iceland. They were identified as Cystofilobasidium lari-marini, Cystofilobasidium capitatum, Cryptococcus macerans and Cryptococcus aquaticus species by sequence analysis of rDNA regions. Growth behavior of the isolates was investigated. All strains could grow at 2 degrees C. Addition of glucose to pectin-containing culture medium had a repressive effect on enzyme production except for C. aquaticus, which showed increased polygalacturonase activity. Optimal temperature for enzyme production for the Cystofilobasidium strains was 14 degrees C, while that for the Cryptococcus strains was lower. Among the isolates, C. lari-marini S3B produced highest levels of enzyme activity at pH 3.2. Preliminary characterization of the polygalacturonases in the culture supernatant showed the enzyme from Cystofilobasidium strains to be optimally active at 40 degrees C and pH 5, and that from the Cryptococcus strains at 50 degrees C and pH 4. The polygalacturonase from C. macerans started to lose activity after 1 h of incubation at 40 degrees C, while that from the other strains had already lost activity at 30 degrees C. All the strains except C. aquaticus produced isoenzymes of polyglacturonase. In addition to polygalacturonase, the Cystofilobasidium strains produced pectin lyase, C. aquaticus pectin esterase, and C. macerans pectin lyase, pectate lyase and pectin esterase.