The purification and characterization of phosphonopyruvate hydrolase, a novel carbon-phosphorus bond cleavage enzyme from Variovorax sp. Pal2.

Phosphonopyruvate hydrolase, a novel bacterial carbon-phosphorus bond cleavage enzyme, was purified to homogeneity by a series of chromatographic steps from cell extracts of a newly isolated environmental strain of Variovorax sp. Pal2. The enzyme was inducible in the presence of phosphonoalanine or phosphonopyruvate; unusually, its expression was independent of the phosphate status of the cell. The native enzyme had a molecular mass of 63 kDa with a subunit mass of 31.2 kDa. Activity of purified phosphonopyruvate hydrolase was Co2+-dependent and showed a pH optimum of 6.7–7.0. The enzyme had a Km of 0.53 mM for its sole substrate, phosphonopyruvate, and was inhibited by the analogues phosphonoformic acid, 3-phosphonopropionic acid, and hydroxymethylphosphonic acid. The nucleotide sequence of the phosphonopyruvate hydrolase structural gene indicated that it is a member of the phosphoenolpyruvate phosphomutase/isocitrate lyase superfamily with 41% identity at the amino acid level to the carbon-to-phosphorus bond-forming enzyme phosphoenolpyruvate phosphomutase from Tetrahymena pyriformis. Thus its apparently ancient evolutionary origins differ from those of each of the two carbon-phosphorus hydrolases that have been reported previously; phosphonoacetaldehyde hydrolase is a member of the haloacetate dehalogenase family, whereas phosphonoacetate hydrolase belongs to the alkaline phosphatase superfamily of zinc-dependent hydrolases. Phosphonopyruvate hydrolase is likely to be of considerable significance in global phosphorus cycling, because phosphonopyruvate is known to be a key intermediate in the formation of all naturally occurring compounds that contain the carbon-phosphorus bond.

Adolescents' educational outcomes in a social ecology of parenting, family, and community risks in Northern Ireland

This study examines the influence of social ecological risks within the domains of parenting, family environment, and community in the prediction of educational outcomes for 770 adolescents (49% boys, 51% girls, M = 13.6 years, SD = 2.0) living in a setting of protracted political conflict, specifically working class areas of Belfast, Northern Ireland. Controlling for religious community, age, and gender, youths' lower academic achievement was associated with family environments characterized by high conflict and low cohesion. School behaviour problems were related to greater exposure to community violence, or sectarian and nonsectarian antisocial behaviour. Youths' expectations about educational attainment were undermined by conflict in the family environment and antisocial behaviour in the community, as well as parenting low in warmth and behavioural control. Findings underscore the importance of considering family and community contributions to youths' educational outcomes. Suggestions regarding targeted interventions toward promoting resilience are discussed, such as assessing both child and family functioning, developing multidimensional interventions for parents, and building community partnerships, among others.

Trajectories of Adolescent Aggression and Family Cohesion: The Potential to Perpetuate or Ameliorate Political Conflict

Correlations between intergroup violence and youth aggression are often reported. Yet longitudinal research is needed to understand the developmental factors underlying this relation, including between-person differences in within-person change in aggression through the adolescent years. Multilevel modeling was used to explore developmental and contextual influences related to risk for youth aggression using 4 waves of a prospective, longitudinal study of adolescent/mother dyad reports (N = 820; 51% female; 10–20 years old) in Belfast, Northern Ireland, a setting of protracted political conflict. Experience with sectarian (i.e., intergroup) antisocial behavior predicted greater youth aggression; however, that effect declined with age, and youth were buffered by a cohesive family environment. The trajectory of aggression (i.e., intercepts and linear slopes) related to more youth engagement in sectarian antisocial behavior; however, being female and having a more cohesive family were associated with lower levels of youth participation in sectarian acts. The findings are discussed in terms of protective and risk factors for adolescent aggression, and more specifically, participation in sectarian antisocial behavior. The article concludes with clinical and intervention implications, which may decrease youth aggression and the perpetuation of intergroup violence in contexts of ongoing conflict.