Informed consent in research ethics: An analysis from the perspective of Luhmann’s social systems theory

We explore the origins and dynamics of ethical communication with reference to the requirements for informed consent provision in research ethics. We adopt the analytical framework developed in Luhmann’s social systems theory to illustrate how ethical communication about informed consent has developed in the medical, legal and scientific systems. We would like to suggest that the development of ethical communication is the result of the developing semantics of individuality and personhood. Our analysis adds specific observations about how communication about research ethics, and informed consent specifically, reduces complexity in an increasingly functionally differentiated society

Cooperativity in long-range gene regulation by the λ CI repressor

Effective repression of cI transcription from P(RM) by the bacteriophage λ CI repressor requires binding sites (O(L)) located 2.4 kb from the promoter. A CI tetramer bound to O(L)1.O(L)2 interacts with a tetramer bound near P(RM) (O(R)1.O(R)2), looping the intervening DNA. We previously proposed that in this CI octamer:DNA complex, the distant O(L)3 operator and the weak O(R)3 operator overlapping P(RM) are juxtaposed so that a CI dimer at O(L)3 can cooperate with a CI dimer binding to O(R)3. Here we show that O(L)3 is necessary for effective repression of P(RM) and that the repressor at O(L)3 appears to interact specifically with the repressor at O(R)3. The O(L)3-CI-O(R)3 interaction involves the same CI interface used for short-range dimer-dimer interactions and does not occur without the other four operators. The long-range interactions were incorporated into a physicochemical model, allowing estimation of the long-range interaction energies and showing the lysogenic state to be ideally poised for CI negative autoregulation. The results establish the λ system as a powerful tool for examining long-range gene regulatory interactions in vivo