Biochemical characterization of wild-type and mutant isoamylases of Chlamydomonas reinhardtii supports a function of the multimeric enzyme organization in amylopectin maturation.

Chlamydomonas reinhardtii mutants of the STA8 gene produce reduced amounts of high amylose starch and phytoglycogen. In contrast to the previously described phytoglycogen-producing mutants of C. reinhardtii that contain no residual isoamylase activity, the sta8 mutants still contained 35% of the normal amount of enzyme activity. We have purified this residual isoamylase and compared it with the wild-type C. reinhardtii enzyme. We have found that the high-mass multimeric enzyme has reduced its average mass at least by one-half. This coincides with the disappearance of two out of the three activity bands that can be seen on zymogram gels. Wild-type and mutant enzymes are shown to be located within the plastid. In addition, they both act by cleaving off the outer branches of polysaccharides with no consistent difference in enzyme specificity. Because the mutant enzyme was demonstrated to digest phytoglycogen to completion in vitro, we propose that its inability to do so in vivo supports a function of the enzyme complex architecture in the processing of pre-amylopectin chains.

[Psychopathy and evaluation of violent behavior in a psychiatric security milieu]. / Psychopathie et évaluation des comportements violents en milieu psychiatrique de sécurité.

This study examines risks of violent behavior among 62 offenders in a belgian psychiatric security institution. Two variables were assessed as predictor of the subjects' history of violent behavior recorded in their medical files: (1) subjective classification as "violent" vs "non-violent" by care taking personnel; and (2) scores on Hare's (1991) Revised Psychopathy Checklist (PCL-R). The study assessed also the score of the Michigan Actuarial Scale of Violent Behavior (MARSS) which was not considered as predictor. The PCL-R, the subjective classification and the MARSS were found to be highly intercorrelated. Regression analysis suggest that the PCL-R is a significant predictor of violent behavior. The use of this instrument for the prediction of violent behavior is thus encouraged.