Articles of Significant Interest Selected from This Issue by the Editors

摘要

Nisin was discovered almost 90 years ago. Most nisin producers belong to the genus Lactococcus and have been isolated from food sources. O'Connor et al. (p. 39533960) describe the isolation of Streptococcus hyointestinalis DPC6484, a porcine intestinal isolate which produces a novel variant of nisin. The new variant, nisin H, differs from the canonical nisin A at 5 of the 34 residues. The finding that intestinal strains produce nisin suggests new avenues for research into the role of this bacteriocin in the gutfrom microbiota homeostasis to infection control to host signaling.Irradiation of sediment microcosms with gamma radiation doses relevant to the bioremediation of radionuclide-contaminated land and the geodisposal of radioactive waste have revealed significant, and somewhat surprising, shifts in the phylogenetic composition and activities of microbial communities. Brown et al. (p. 40144025) demonstrate that, despite these doses, biogeochemical processes may not be restricted as expected. Rather, electron-accepting processes, such as Fe(III) reduction, may be stimulated by radiation. This study raises the possibility that enhanced reduction of alternative electron acceptors by low doses of radiation could provide the basis for novel ecosystems in engineered and natural environments, including the deep biosphere.