Common antigenic determinants of pneumococcal penicillin-binding protein (PBP) 1a and Streptococcus pyogenes PBP 2

Abstract Antisera raised against penicillin-binding protein (PBP) 1a of Streptococcus pneumoniae reacted with PBP 2 in certain strains of Streptococcus pyogenes . Cross-reactivity could be demonstrated on immunoblots as well as by immunoprecipitation of native solubilised proteins, indicating a similar structural arrangement also in the native form of the two PBPs.     

Understanding libertarian morality: the psychological dispositions of self-identified libertarians

Libertarians are an increasingly prominent ideological group in U.S. politics, yet they have been largely unstudied. Across 16 measures in a large web-based sample that included 11,994 self-identified libertarians, we sought to understand the moral and psychological characteristics of self-described libertarians. Based on an intuitionist view of moral judgment, we focused on the underlying affective and cognitive dispositions that accompany this unique worldview. Compared to self-identified liberals and conservatives, libertarians showed 1) stronger endorsement of individual liberty as their foremost guiding principle, and weaker endorsement of all other moral principles; 2) a relatively cerebral as opposed to emotional cognitive style; and 3) lower interdependence and social relatedness. As predicted by intuitionist theories concerning the origins of moral reasoning, libertarian values showed convergent relationships with libertarian emotional dispositions and social preferences. Our findings add to a growing recognition of the role of personality differences in the organization of political attitudes.     

Interaction of non-lytic beta-lactams with penicillin-binding proteins in Streptococcus pneumoniae

The monobactam aztreonam and the cephalosporin ceftazidime, beta-lactam antibiotics that possess the same side chain R1, showed unusual effects on exponentially growing pneumococci compared to other beta-lactams. Both antibiotics did not induce lysis even at concentrations up to 2 mg ml-1, values well above the respective MICs. However, morphological alterations and growth inhibition of the cells were observed at much lower concentrations. Binding to penicillin-binding proteins (PBPs) in vitro could be monitored directly by using anti-aztreonam antiserum and the Western blot technique. Both antibiotics showed high affinity for PBP 3, but had an extremely low affinity for PBP 2b. It is suggested that the failure to bind to PBP 2b is responsible for the failure to induce lysis in pneumococci.