Interbacterial predation as a strategy for DNA acquisition in naturally competent bacteria.

Natural competence enables bacteria to take up exogenous DNA. The evolutionary function of natural competence remains controversial, as imported DNA can act as a source of substrates or can be integrated into the genome. Exogenous homologous DNA can also be used for genome repair. In this Opinion article, we propose that predation of non-related neighbouring bacteria coupled with competence regulation might function as an active strategy for DNA acquisition. Competence-dependent kin-discriminated killing has been observed in the unrelated bacteria Vibrio cholerae and Streptococcus pneumoniae. Importantly, both the regulatory networks and the mode of action of neighbour predation differ between these organisms, with V. cholerae using a type VI secretion system and S. pneumoniae secreting bacteriocins. We argue that the forced release of DNA from killed bacteria and the transfer of non-clonal genetic material have important roles in bacterial evolution

[FeFe] Hydrogenase Models: an Overview

International audienceThis chapter focuses on models for the mixed‐valent Hox state as well as protonation reactions of Hred models and on some significant insights into proton reduction chemistry. Although numerous [FeFe] hydrogenase model complexes exist, synthetic access to iron‐chalcogenolato compounds is limited to substitution reactions and oxidative additions. During the past two decades, significant development in modeling the active site of [FeFe] hydrogenases allowed to reveal the fundamental modes of action at the molecular level