The -related encodes functional type II toxin-antitoxin systems.

Bacterial toxin-antitoxin (TA) systems are widespread in chromosomes and plasmids of free-living microorganisms, but only a few have been identified in obligate intracellular species. We found seven putative type II TA modules in , a -related species that is able to infect a very broad series of eukaryotic hosts, ranging from protists to mammalian cells. The RNA levels of TA systems are significantly upregulated by iron starvation and novobiocin, but they are not affected by antibiotics such as β-lactams and glycopeptides, which suggests different mechanisms underlying stress responses.

Adaptive β-lactam resistance from an inducible efflux pump that is post-translationally regulated by the DjlA co-chaperone.

The acquisition of multidrug resistance (MDR) determinants jeopardizes treatment of bacterial infections with antibiotics. The tripartite efflux pump AcrAB-NodT confers adaptive MDR in the polarized α-proteobacterium Caulobacter crescentus via transcriptional induction by first-generation quinolone antibiotics. We discovered that overexpression of AcrAB-NodT by mutation or exogenous inducers confers resistance to cephalosporin and penicillin (β-lactam) antibiotics.

Temperature Affects the Host Range of Rhabdochlamydia porcellionis.

The family is a recent addition to the phylum. Its members were discovered in cockroaches and woodlice, but recent metagenomics surveys demonstrated the widespread distribution of this family in the environment. It was, moreover, estimated to be the largest family of the phylum based on the diversity of its 16S rRNA encoding gene.

Transcriptional Landscape of Aberrant Bodies Induced by Iron Starvation.

Chronic infections caused by obligate intracellular bacteria belonging to the order are related to the formation of persistent developmental forms called aberrant bodies (ABs), which undergo DNA replication without cell division. These enlarged bacteria develop and persist upon exposure to different stressful conditions such as β-lactam antibiotics, iron deprivation and interferon-γ. However, the mechanisms behind ABs biogenesis remain uncharted.

Secretion Relieves Translational Co-repression by a Specialized Flagellin Paralog.

How cellular checkpoints couple the orderly assembly of macromolecular machines with cell-cycle progression is poorly understood. The alpha-proteobacterium Caulobacter crescentus assembles a single polar flagellum during each cell cycle. We discovered that the expression of multiple flagellin transcripts is licensed by a translational checkpoint responsive to a dual input signal: a secretion-competent hook-basal-body (HBB) structure and a surge in the FlaF secretion chaperone during cytokinesis, instructed by the cell-cycle program.