The Mobile Genetic Element RD2 Affects Colonization Potential of Different GAS Serotypes.

M-type 28 (M28) Streptococcus pyogenes (group A Streptococcus [GAS]) strains are highly associated with life-threatening puerperal infections. Genome sequencing has revealed a large mobile genetic element, RD2, present in most M28 GAS isolates but not found widely in other serotypes. Previous studies have linked RD2 to the ability of M28 GAS to colonize the vaginal tract.

Characterization of Electrogenic Gut Bacteria.

While electrogenic, or electricity-producing, Gram-negative bacteria predominantly found in anaerobic habitats have been intensively explored, the potential of Gram-positive microbial electrogenic capability residing in a similar anoxic environment has not been considered. Because Gram-positive bacteria contain a thick non-conductive cell wall, they were previously believed to be very weak exoelectrogens. However, with the recent discovery of electrogenicity by Gram-positive pathogens and elucidation of their electron-transfer pathways, significant and accelerated attention has been given to the discovery and characterization of these pathways in the members of gut microbiota.

The Influence of Biofilms in the Biology of Plasmids.

The field of plasmid biology has historically focused on bacteria growing in liquid culture. Surface-attached communities of bacterial biofilms have recently been understood to be the normal environment of bacteria in the natural world. Thus, studies examining plasmid replication, maintenance, and transfer in biofilms are essential for a true understanding of bacterial plasmid biology.

The influence of biofilms in the biology of plasmids.

The field of plasmid biology has historically focused on bacteria growing in liquid culture. Surface attached communities of bacterial biofilms have recently been understood to be the normal environment of bacteria in the natural world. Thus, studies examining plasmid replication, maintenance, and transfer in biofilms are essential for a true understanding of bacterial plasmid biology.

Peptide pheromone signaling in Streptococcus and Enterococcus.

Intercellular chemical signaling in bacteria, commonly referred to as quorum sensing (QS), relies on the production and detection of compounds known as pheromones to elicit coordinated responses among members of a community. Pheromones produced by Gram-positive bacteria are comprised of small peptides. Based on both peptide structure and sensory system architectures, Gram-positive bacterial signaling pathways may be classified into one of four groups with a defining hallmark: cyclical peptides of the Agr type, peptides that contain Gly-Gly processing motifs, sensory systems of the RNPP family, or the recently characterized Rgg-like regulatory family.

Active, soluble recombinant melittin purified by extracting insoluble lysate of Escherichia coli without denaturation.

Cell lytic peptides are a class of drugs that can be used to selectively kill invading organisms or diseased cells. Several of these peptides have been identified as potential therapeutics. Herein, we report a novel process for purifying recombinant melittin, a cell lytic peptide that inserts into the membranes of cells causing cell lysis, from Escherichia coli.

Interspecies communication among commensal and pathogenic streptococci.

Unlabelled: Quorum sensing (QS) regulates diverse and coordinated behaviors in bacteria, including the production of virulence factors, biofilm formation, sporulation, and competence development. It is now established that some streptococci utilize Rgg-type proteins in concert with short hydrophobic peptides (SHPs) to mediate QS, and sequence analysis reveals that several streptococcal species contain highly homologous Rgg/SHP pairs. In group A streptococcus (GAS), two SHPs (SHP2 and SHP3 [SHP2/3]) were previously identified to be important in GAS biofilm formation.

Proteolytically activated anti-bacterial hydrogel microspheres.

Hydrogels are finding increased clinical utility as advances continue to exploit their favorable material properties. Hydrogels can be adapted for many applications, including surface coatings and drug delivery. Anti-infectious surfaces and delivery systems that actively destroy invading organisms are alternative ways to exploit the favorable material properties offered by hydrogels.

Antagonistic self-sensing and mate-sensing signaling controls antibiotic-resistance transfer.

Conjugation is one of the most common ways bacteria acquire antibiotic resistance, contributing to the emergence of multidrug-resistant "superbugs." Bacteria of the genus Enterococcus faecalis are highly antibiotic-resistant nosocomial pathogens that use the mechanism of conjugation to spread antibiotic resistance between resistance-bearing donor cells and resistance-deficient recipient cells. Here, we report a unique quorum sensing-based communication system that uses two antagonistic signaling molecules to regulate conjugative transfer of tetracycline-resistance plasmid pCF10 in E.

Enterococcus faecalis endocarditis severity in rabbits is reduced by IgG Fabs interfering with aggregation substance.

Background: Enterococcus faecalis is a significant cause of infective endocarditis, an infection of the heart endothelium leading to vegetation formation (microbes, fibrin, platelets, and host cells attached to underlying endothelial tissue). Our previous research determined that enterococcal aggregation substance (AS) is an important virulence factor in causation of endocarditis, although endocarditis may occur in the absence of AS production. Production of AS by E.