A Streptomyces tendae Specialized Metabolite Inhibits Quorum Sensing in Group A Streptococcus.

Quorum sensing (QS) is a means of bacterial communication accomplished by microbe-produced signals and sensory systems. QS systems regulate important population-wide behaviors in bacteria, including secondary metabolite production, swarming motility, and bioluminescence. The human pathogen Streptococcus pyogenes (group A Streptococcus [GAS]) utilizes Rgg-SHP QS systems to regulate biofilm formation, protease production, and activation of cryptic competence pathways.

Storage and Algal Association of Bacteria That Protect from Grazing by .

Loss of algal production from the crashes of algal mass cultivation systems represents a significant barrier to the economic production of microalgal-based biofuels. Current strategies for crash prevention can be too costly to apply broadly as prophylaxis. Bacteria are ubiquitous in microalgal mass production cultures, however few studies investigate their role and possible significance in this particular environment.

Diaza-anthracene Antibiotics from a Freshwater-Derived Actinomycete with Selective Antibacterial Activity toward .

Multidrug- and extensively drug-resistant strains of are resistant to first- and second-line drug regimens and resulted in 210,000 fatalities in 2013. In the current study, we screened a library of aquatic bacterial natural product fractions for their ability to inhibit this pathogen. A fraction from a Lake Michigan bacterium exhibited significant inhibitory activity, from which we characterized novel diazaquinomycins H and J.

Phylum-specific regulation of resistomycin production in a Streptomyces sp. via microbial coculture.

Actinomycete genomes are encoded with immense potential to produce secondary metabolites, however standard laboratory culture experiments rarely provide the conditions under which associated biosynthetic pathways are expressed. Despite years of research attempting to access these pathways and aside from a few well-studied bacterial quorum sensing systems, little is known about the specificity of secondary metabolite regulation in bacteria, such as the conditions under which a bacterium produces an antibiotic and the extent to which it does so in recognition of a particular species in the immediate environment. In the current study, we observed that the cocultivation of a Streptomyces sp.

Tools for characterizing bacterial protein synthesis inhibitors.

Many antibiotics inhibit the growth of sensitive bacteria by interfering with ribosome function. However, discovery of new protein synthesis inhibitors is curbed by the lack of facile techniques capable of readily identifying antibiotic target sites and modes of action. Furthermore, the frequent rediscovery of known antibiotic scaffolds, especially in natural product extracts, is time-consuming and expensive and diverts resources that could be used toward the isolation of novel lead molecules.

Potential chemopreventive activity of a new macrolide antibiotic from a marine-derived Micromonospora sp.

Agents capable of inducing phase II enzymes such as quinone reductase 1 (QR1) are known to have the potential of mediating cancer chemopreventive activity. As part of a program to discover novel phase II enzyme-inducing molecules, we identified a marine-derived actinomycete strain (CNJ-878) that exhibited activity with cultured Hepa 1c1c7 cells. Based on this activity, a new macrolide, juvenimicin C (1), as well as 5-O-α-L-rhamnosyltylactone (2), were isolated from the culture broth of a Micromonospora sp.