Journal of Bacteriology

Staphylococcus aureus is a leading cause of biofilm-associated infections, in which communities of bacterial cells are encased in an extracellular matrix composed of polysaccharides, proteins, and extracellular DNA (eDNA) that protect bacteria from host immune defense and antibiotics. Despite their importance, the mechanisms by which matrix components are released from bacterial cells and incorporated into the biofilm matrix remain poorly understood. Using a drip-flow biofilm system, we showed...

The genus Streptococcus contains some of the most important commensals and pathogens of the human microbiome. To obtain the fatty acids required for cell membranes, Streptococcus either produce fatty acids de novo through the fatty acid biosynthesis (fab) pathway or uptake host fatty acids through the fatty acid kinase (fak) pathway. Although both the fab and fak pathways represent potential therapeutic targets to prevent or treat infection, progress is limited because of an incomplete...

Biofilms are the predominant lifestyle for bacteria. Biofilm abundance makes understanding their behavior important for different research domains. These domains can have different information and reporting standards. Information reporting standards have been proposed for some biofilm research methods. Standard methods and consensus standards have also been promulgated. We propose dimensional analysis to encourage abundant information reporting and facilitate comparative analysis. Dimensional...

Horizontal gene transfer is an important evolutionary process by which DNA is exchanged between cells that are physically co-located but not direct evolutionary descendants. Horizontal transfer of highly divergent DNA is relatively easy to detect and can produce major phenotypic changes, exemplified by the acquisition of antibiotic resistance determinants. However, transfer of high-identity DNA, for example, between strains of the same species, is likely to be more frequent, harder to detect,...

Pathogenic and persistent biofilms are a major challenge in medicine and industry, acting as resilient microbial communities that resist antibiotics and cause persistent infections. In this review, we discuss pulcherriminic acid, a promising iron-chelating molecule produced by antagonistic Bacillus subtilis as a natural weapon against persistent biofilms, particularly those formed by pathogens such as Candida albicans. Drawing on recent research, we explore pulcherriminic acid biosynthesis, its...

The genus Neisseria includes two human pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, in addition to commensal species that also inhabit human and animal hosts. One of the features that occurs during neisserial host colonization is biofilm formation. In other bacteria, biofilm formation enables persistence as well as evasion of the host immune system. Extracellular DNA (eDNA) forms a major component of Neisseria biofilms and contributes to initial steps in their formation, as well...

Since its isolation from a Yellowstone hot spring in 1972, Sulfolobus acidocaldarius has become one of the most important model organisms for archaeal biology. Initially studied for its remarkable adaptation to high temperature and low pH, it has evolved into a genetically tractable system that has contributed substantially to our understanding of archaeal physiology, molecular biology, and evolution. Here, we summarize more than 5 decades of research on S. acidocaldarius, highlighting key...

Bacterial ribosomes initiate translation while the nascent transcript is still engaged with RNA polymerase, creating a risk that translating ribosomes will become trapped if RNA polymerase is blocked before transcription of the stop codon. Here we show that DNA-binding proteins block RNA polymerase and translating ribosomes in vitro and in vivo. Translating ribosomes are rescued after they trigger the release of the nascent transcript from RNA polymerase. Following the release of the transcript,...

Obligate intracellular pathogenic bacteria belonging to the order Rickettsiales include several important emerging pathogens causing major health and economic impact to humans, companion animals, and agricultural animals. Despite some recent progress, the lack of well-established genetic manipulation methods for diverse research applications remains a challenge. We recently reported the establishment of targeted mutagenesis to disrupt genes in Ehrlichia and Anaplasma species. Many essential...

The pathogenic bacterium Vibrio cholerae is aquatic and can be cultivated in nutrient media with increased salt concentration. To maintain osmotic balance, V. cholerae uses Na^(+)/H^(+) antiporters and a Na^(+)-translocating NADH:quinone oxidoreductase (Na^(+)-NQR). The exact contribution of the various Na^(+)/H^(+) antiporters to maintaining Na^(+) and H^(+) homeostasis in V. cholerae is unclear. However, genetic studies indicate the major Na^(+)/H^(+) antiporter NhaA and the Na^(+)-NQR are...

Cupriavidus metallidurans is able to grow in the presence of transition metal mixtures with high concentrations and varying compositions. This ability is mediated by a multitude of metal transport and repository systems. To reveal the genetic regulation underlying these physiological processes, 12,914 transcriptional start sites (TSSs) in metal-stressed and metal-starved cells were determined, and regulatory tags assigned to each TSS. Subsequently, the sense and antisense transcripts downstream...

The secreted phospholipase C/sphingomyelinase, PlcH, is the heat-labile hemolysin of Pseudomonas aeruginosa and one of its important secreted virulence factors. While there are known and suspected genes that impact PlcH production in P. aeruginosa, we sought to identify additional genes by screening the PA14 transposon mutant library to measure extracellular PlcH enzyme activity induced by choline. The library as a whole had a log2-normal distribution of nitrophenylphosphorylcholine hydrolysis...

In recent years, Klebsiella pneumoniae (Kpn) has evolved into a global public health threat. Convergent Kpn lineages that are both hypervirulent and multidrug-resistant have emerged and can cause community-acquired, drug-resistant infections, with increased mortality. A major driver of hypervirulence in Kpn is hypermucoviscosity (HMV), a phenotype historically associated with increased capsular polysaccharide (CPS) production. Recent findings show that HMV is a distinct trait characterized by...

Pseudomonas aeruginosa is a metabolically versatile pathogen that thrives in host environments characterized by gradients of oxygen and nutrient availability. Although acetate is an abundant carbon source in chronic infections, the mechanisms governing P. aeruginosa acetate assimilation remains poorly understood. In many bacteria, acetate utilization occurs via the low-carbon-flux acetyl-CoA synthetase (Acs) or the high-carbon-flux acetate kinase/phosphotransacetylase (AckA-Pta) pathways. Here,...

Streptococcus gordonii is a gram-positive oral bacterium capable of adhering to a variety of biotic and abiotic surfaces and forming biofilms. To characterize physiological changes associated with biofilm formation in S. gordonii, we investigated the roles of two putative GCN5-related N-acetyltransferases (GNATs), SGO_2030 and SGO_2031, in in vitro biofilm formation on saliva-coated surfaces using the laboratory strain DL1. Our results demonstrate that SGO_2031, but not SGO_2030, seems to...