Journal of Bacteriology

Iron is a crucial micronutrient for <i>Pseudomonas aeruginosa</i> survival and virulence, yet it can also be toxic due to the production of reactive oxygen species. The PrrF small regulatory RNAs (sRNAs) are transcribed in iron-limiting conditions and block the expression of several mRNAs involved in <i>P. aeruginosa</i>'s oxidative stress response. Here, we make the surprising discovery that oxi…

Iron availability affects oceanic primary productivity and the strength of the biological carbon pump. However, the mechanism of iron solubility in hypersaline environments is poorly understood. In this work, we investigated the extremely halophilic archaeon <i>Haloferax volcanii</i> to reduce ferrihydrite under 25% salinity, aiming to elucidate its energy metabolism associated with extracellular…

Uropathogenic <i>Escherichia coli</i> (UPEC) is the leading causative agent of urinary tract infection (UTI). Copper (Cu) is a host effector mobilized to the bladder during the innate immune response activated by acute UTI. <i>E. coli</i> precisely regulates Cu homeostasis via efflux systems because excess Cu is toxic. Long-chain fatty acid (LCFA) homeostasis is critical for the survival of <i>E.…

Nitrogen (N) is essential for bacterial growth, and adaptation to N starvation involves extensive reprogramming of metabolism and gene expression. A hallmark subcellular feature in long-term N-starved <i>Escherichia coli</i> cells is the presence of biomolecular condensates of the major bacterial RNA regulator Hfq. The Hfq condensates, which accumulate gradually during N starvation, contribute to…

Nitrogen-related phosphotransferase (PTS^Ntr) systems are highly conserved and widely distributed in proteobacteria. These systems are thought to enable bacteria to sense and respond to changes in cellular carbon and nitrogen availability. The PTS^Ntr is analogous to the carbohydrate phosphotransferase systems that carry out phosphorylation and uptake of specific carbohydrates…

Surface proteins of gram-positive bacteria are key virulence factors in the human pathogen <i>Staphylococcus aureus</i>. Most surface proteins carry a YSIRK/G-S type signal peptide that promotes cross-wall trafficking and attachment to the septal cell wall during cell division. This study identified several new factors regulating this process through a comprehensive screen. The mutants identified…

Plasmid conjugation drives the spread of antimicrobial resistance genes between different bacterial species. In IncF plasmids, this process relies on tight interactions between an outer-membrane protein in the recipient and the plasmid-encoded TraN, which consists of conserved base and variable tip domains. So far, TraN was only studied in IncF plasmids. We show that IncA/C and IncH plasmids enco…

<i>Pseudomonas syringae</i> pv. tomato (Pst), the causal agent of bacterial speck in tomato, is a model for understanding plant-pathogen coevolution. Within this pathosystem, the emergence of race 1 has traditionally been interpreted as a direct adaptive response to the development of Pto/Prf-mediated resistance in tomato. While race 0 strains are recognized through the type III effectors AvrPto …

Gene expression in mycobacteria relies on both integrative and episomal <i>Escherichia coli</i>-mycobacterium shuttle vectors. However, existing vectors have limited flexibility for adding epitope tags, selectable markers, and fluorescent reporters. To overcome this, we created a modular toolkit consisting of 32 integrative and eight episomal <i>E. coli</i>-mycobacterium shuttle vectors. Each vec…

Over the past 30 years, the study of <i>Mycobacterium tuberculosis</i> has become a vibrant field that supports basic investigation into mycobacteria, wide-ranging studies of <i>M. tuberculosis</i> pathogenesis, and drug and therapeutic development. In this minireview, we highlight the multiple ways in which <i>M. tuberculosis</i> is a model. <i>M. tuberculosis</i> has emerged as a model for prok…

Peptidoglycan is an important structural cell wall polymer that serves to give bacteria their shape and resistance to changes in extracellular solute concentrations. For <i>Chlamydia trachomatis</i>, an obligate intracellular pathogen that divides within a host cell, peptidoglycan is only used for cell division and is not a component of its cell wall. In this study, we characterize the function o…

<i>Pseudomonas aeruginosa</i> is a highly adaptable opportunistic pathogen with a repertoire of mechanisms for surviving in diverse and often challenging environments, yet it is most studied at 37°C as the optimum temperature for growth. To better understand how this bacterium survives in the environment versus the human body, we performed transcriptomics on <i>P. aeruginosa</i> grown at 25°C and…

<i>Pseudomonas aeruginosa</i> is a highly versatile opportunistic pathogen and a major cause of acute, chronic, and even lifelong respiratory infections in people with cystic fibrosis. It can also cause corneal infections, burn/wound infections, and bacteremia. <i>P. aeruginosa</i> is often found in human-associated environments such as hospitals, where it is a frequent cause of nosocomial cathet…

<i>Pseudomonas aeruginosa</i> is an opportunistic pathogen with a complex regulatory network controlling its physiology and virulence. A key component of this network is PsrA, a TetR-family transcriptional regulator initially identified as an activator of <i>rpoS</i>. PsrA participates in multiple processes, including stress responses, fatty acid metabolism, quorum sensing, and secretion-mediated…

In the bacterial world, riboregulation is extremely widespread and controls virtually all aspects of the life of bacterial cells. Riboregulatory mechanisms are very diverse and involve <i>trans</i>- and <i>cis</i>-acting regulatory elements such as small RNAs and riboswitches that are able to control gene expression by direct binding of small molecules. Here, we report a very peculiar and rare ex…

Dual membrane-spanning anti-sigma factors (Dma) are a novel class of regulatory proteins found solely among Bacteroidota. Previous studies demonstrated the importance of Dma1 in vesiculation, but the overall role of the Dma family in Bacteroides physiology remains poorly understood. Here, we show that Dma2 modulates vesiculation and the expression of select polysaccharide utilization loci (PULs) …

In phototrophic cyanobacteria, the signaling molecule bis-(3'-5')-cyclic dimeric-guanosine monophosphate (c-di-GMP) plays important roles in a wide variety of functions associated with environmental conditions, including biofilm formation, motility, heterocyst development, cell size control, phototaxis, and flocculation. However, its role in circadian rhythms, which contribute to fitness under di…

Bacterial niche colonization relies on multiple factors, among which the metabolic capacity to utilize specific substrates is pivotal. As a gut commensal of humans and other vertebrates acting as an intestinal and extraintestinal opportunistic pathogen, <i>Escherichia coli</i> faces such environmental pressures. We therefore aimed to identify (i) metabolic patterns associated with <i>E. coli</i> …

The latest generation of cystic fibrosis transmembrane conductance regulator-targeted modulator therapy, Elexacaftor/Tezacaftor/Ivacaftor (ETI), has significantly improved the clinical outcomes of persons with cystic fibrosis (pwCF) but does not appear to completely eliminate CF respiratory microbial colonization. Here, we analyzed over 4,200 publicly available respiratory microbiomes spanning pr…

Genetic screens are powerful approaches to unveiling new biological insights and ordered redundant transposon libraries have emerged as a primary tool for performing screens with known genetic saturation. Newer sequencing approaches based on combinatorial pooling have lowered the cost and time required to generate these libraries. <i>Caulobacter crescentus</i> is a gram-negative bacterium that ha…