Recent sport psychology research addressing athletic aggression has tended to focus either on the moral or the motivational dimensions of aggressive behavior. The current study utilized both moral and motivational constructs to investigate aggression in young soccer participants (N = 212) from two different age-group leagues: under 12 and under 14. Stepwise multiple regression analyses revealed that players who described themselves as more likely to aggress against an opponent also were more likely to (a) identify a larger number of teammates who would aggress in a similar situation, (b) perceive their coach as placing greater importance on ego-oriented goals, and (c) choose situations featuring preconventional rather than conventional moral motives as more tempting for aggressive action. These results suggest that young athletes’ aggressive behavior is related to their team’s “moral atmosphere,” including team aggressive norms, players’ perceptions of these team norms and coach characteristics, and players’ moral motives for behavior.

This study was designed to extend previous research on aggressive tendencies and moral atmosphere in two ways: (a) to include participants of two skill levels in a summer youth basketball skill camp and (b) to examine the influence of the coach on participants' aggressive tendencies. The participants were 136 youth from either a beginning (n = 89) or an advanced sport camp (n = 47). Results indicated that primary predictors of aggressive tendencies for both skill levels included participants' perception of their teammates' behavior in the same situation and their willingness to injure others if their coach requested. These findings are consistent with previous research establishing team norm as a significant predictor for self-described aggressive tendencies in a sport situation.

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Random mutagenesis was used to improve the alkaline and thermal stability of the xylanase (XynA) from Thermomyces lanuginosus. Error-prone PCR reactions were carried out; the PCR products were cloned into Escherichia coli and a library of 960 clones was selected on xylan-containing agar plates. The crude filtrates of positive xylanase producers were screened at 80 degrees C and tested separately at pH 10 for alkaline tolerance. The native XynA lost 80% activity after 90 min at 80 degrees C and lost 70% activity at pH 10. Conversely, the most thermostable variant, G41, retained 75% activity after 90 min at 80 degrees C and the best alkali-stable variant, G53, retained 93% activity at pH 10. Sequence analysis revealed four amino acid substitutions in G41 and a single substitution in G53. These variants, therefore, have improved thermal and alkaline stability and are ideal candidates for DNA shuffling experiments to produce a robust xylanase for industrial application.