Bacteria use exogenous peptidoglycan as a danger signal to trigger biofilm formation.

For any organism, survival is enhanced by the ability to sense and respond to threats in advance. For bacteria, danger sensing among kin cells has been observed, but the presence or impacts of general danger signals are poorly understood. Here we show that different bacterial species use exogenous peptidoglycan fragments, which are released by nearby kin or non-kin cell lysis, as a general danger signal.

Metabolic mutations reduce antibiotic susceptibility of E. coli by pathway-specific bottlenecks.

Metabolic variation across pathogenic bacterial strains can impact their susceptibility to antibiotics and promote the evolution of antimicrobial resistance (AMR). However, little is known about how metabolic mutations influence metabolism and which pathways contribute to antibiotic susceptibility. Here, we measured the antibiotic susceptibility of 15,120 Escherichia coli mutants, each with a single amino acid change in one of 346 essential proteins.

Transfection of a Molecular Clone of Naegleria gruberi rDNA into N. gruberi Trophozoites.

All ribosomal genes of Naegleria trophozoites are maintained in a closed circular extrachromosomal ribosomal DNA (rDNA) containing element (CERE). While little is known about the CERE, a complete genome sequence analysis of three Naegleria species clearly demonstrates that there are no rDNA cistrons in the nuclear genome. Furthermore, a single DNA origin of replication has been mapped in the N.

In Vivo Microrheology Reveals Local Elastic and Plastic Responses Inside 3D Bacterial Biofilms.

Bacterial biofilms are highly abundant 3D living materials capable of performing complex biomechanical and biochemical functions, including programmable growth, self-repair, filtration, and bioproduction. Methods to measure internal mechanical properties of biofilms in vivo with spatial resolution on the cellular scale have been lacking. Here, thousands of cells are tracked inside living 3D biofilms of the bacterium Vibrio cholerae during and after the application of shear stress, for a wide range of stress amplitudes, periods, and biofilm sizes, which revealed anisotropic elastic and plastic responses of both cell displacements and cell reorientations.

Complete sequence of the closed circular extrachromosomal element of De Jonckheere (strain Singh).

The DNA encoding the ribosomal RNA in is encoded on closed circular extrachromosomal ribosomal DNA-containing elements (CERE) in the nucleolus. In this report, we describe the sequence of the CERE of De Jonckheere (strain Singh).