Macquarie University

About: Macquarie University is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 14075 authors who have published 47673 publications receiving 1416184 citations. The organization is also known as: Macquarie uni.

Structure and function of 59-base element recombination sites associated with mobile gene cassettes

Abstract: The integration of gene cassettes into integrons is effected by site-specific recombination catalysed by an integrase, IntI, encoded by the integron The cassette-associated recombination sites, 59-base elements, are not highly conserved and vary in length from 57 to 141 bp They can be identified by their location and the relationship of over 20 bp at their outer ends to consensus sequences that are imperfect inverted repeats of one another The recombination cross-over occurs close to one end of the 59-base element, within a conserved core site with the consensus sequence GTTAGGC or GTTRRRY By introducing single-base changes at each of these positions in the aadB 59-base element, bases that are critical for site activity were identified The recombination cross-over was also localized to a unique position between the adjacent G and T residues Changes introduced in the conserved AAC of the inverse core site (GCCTAAC or RYYYAAC) located at the opposite end of the 59-base element also reduced site activity but to a lesser extent Sequences of rare recombinants revealed an alternative position for strand exchange and led to the conclusion that 59-base elements comprise two simple sites, analogous to those recognized by other integrases, with each simple site made up of a pair of inversely oriented IntI binding domains separated by a spacer of 7 or 8 bp Re-examination of the sequences of all known 59-base elements revealed that this simple site configuration was present at both the left and right ends in all 59-base elements The identity of bases in the spacer is not required for efficient recombination and the cross-over is located at one end of the spacer, suggesting that during IntI1-mediated recombination only one strand exchange occurs

Family process and child anxiety and aggression: an observational analysis

Abstract: Barrett, Rapee, Dadds, and Ryan (1996) described a phenomenon whereby family discussions magnified the style of children's problem solving in a way characteristic of their particular clinical diagnosis. That is, anxious children became more avoidant, aggressive children more aggressive, and nonclinic children more prosocial, after discussing ambiguous hypothetical situations with their parents. This study examined specific sequences of communications exchanged between parents and children hypothesized to underlie this family exacerbation of child cognitive style. Family discussions were videotaped and categorized for groups of anxious, aggressive, and nonclinic children and their parents. Results revealed differences between groups of parents in frequency of agreeing with and listening to their child and the frequency of pointing out positive consequences. Conditional probability analyses showed that parents of anxious children were more likely to reciprocate avoidance, while parents of nonclinic children were more likely to agree with and listen to prosocial plans from their child. Differences in parent behaviors observed during the family discussions were reliably associated with the child's response to the ambiguous situation proposed after the family discussion. Results support a model of developmental anxiety and aggression that emphasizes the interaction of family processes and social-cognitive development in the child.