Articles of Significant Interest Selected from This Issue by the Editors

摘要

The draft genome of a Guaymas Basin (Mexico) Beggiatoa ( Maribeggiatoa ) filament has yielded clues to its physiology and evolutionary history. MacGregor et al. (p. 39743985) report here that the closest relatives of several putative mobile elements in this sequence, including introns and inteins, exist in cyanobacteria and certain filamentous bacteria. There are also multiple xisHI -like sequences, whose characterized representatives are required for terminal heterocyst differentiation in some cyanobacteria; it is speculated that they may play some similar role along Beggiatoa filaments. A first look at other cyanobacterium-like sequences suggests that sensory genes in particular may have been exchanged, perhaps in mixed-species microbial mats. Enterococcus faecalis is an opportunistic bacterium that is part of the normal human gut microbiota but also a frequent causative agent of nosocomial infections. To illuminate host-microbe interactions, Leanti La Rosa and colleagues (p. 39863997) employed a luxABCDE -based reporter system, showing that the colonization and growth dynamics of E. faecalis nosocomial and commensal isolates in the intestinal lumen are greatly affected by antibiotics. This system also enabled organ-specific assessment of bacterial burden and virulence gene expression during systemic infection. The presented lux reporter system is established as a valuable tool to facilitate in vivo studies of gene expression and pathogenic behavior in mammalian hosts.