Articles of Significant Interest Selected from This Issue by the Editors
Phase-Variable Changes in Capsule Structure Modulate Serum Resistance in Campylobacter jejuni
Phase variation of genes encoding surface antigens of Campylobacter jejuni results in multiple genotypes that are selected for fitness in various environments. Pequegnat et al. (e00027-17) demonstrate that phase-variable methyl phosphoramidate (MeOPN) modifications on the capsule prevent activation of the classical arm of the complement cascade by blocking access of preexisting antibodies in normal human sera to the polysaccharide chain. A newly recognized site of modification, on the 4 position of galactose, is more critical to complement resistance than other sites. Exposure to normal human serum selects for variants in the population expressing this MeOPN modification.
RpoH Sigma Factors Are Required in Rhodobacter sphaeroides To Quickly Resume Growth after Extended Stationary Phase
For successful survival in natural environments, bacteria need to survive long phases of nutrient limitations or other unfavorable conditions and to resume growth promptly if conditions improve. Remes et al. (e00249-17) have analyzed the transcriptome of the alphaproteobacterium Rhodobacter sphaeroides in different growth phases, revealing a strong effect of the length of stationary phase on gene expression in outgrowth. The alternative sigma factors RpoHI and RpoHII, important regulators of stress responses in alphaproteobacteria, are involved in activating a large number of genes in outgrowth after long stationary phase (about 60 h) to guarantee a quick transition to active growth.
- Copyright © 2017 American Society for Microbiology.
