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Consistent with the anti-hyphal properties of WED, the expression of ALS3 and HWP1 were diminished. Ketoconazole failed to reproduce the effects of WED on NRG1, TUP1 and EFG1. WED blunted efflux pump activity; this effect was in direct contrast to that of ketoconazole. WED exposure compromised cellular metabolism. In the presence of ketoconazole, the changes in cell wall composition and loss of membrane integrity. This work presents first evidence that weak electric field is useful in managing pathogens which are otherwise known to be antibiotic resistant.
Conflict of interest statement: Declaration of Competing Interest CKS, in his capacity as a co-developer of the technology, has minor commercial interest in Vomaris Inc. He is also a paid consultant for the company. A Chemical Counterpunch: Chromobacterium violaceum ATCC 31532 Produces Violacein in Response to Translation-Inhibiting Antibiotics. Antibiotics produced by bacteria play important roles in microbial interactions and competition Antibiosis can induce resistance mechanisms in target organisms, and at sublethal doses, antibiotics have been shown to globally alter gene strain 2AW. induces Chromobacterium violaceum ATCC 31532 to produce the purple antibiotic violacein. Sublethal doses of other antibiotics that similarly target the polypeptide elongation step of translation likewise induced violacein formation and virulence against Drosophila melanogaster were also induced by translation-inhibiting antibiotics, and we identified an antibiotic-induced response (air) two-component regulatory system that is required for these responses. Genetic analyses indicated a connection between the Air system, quorum-dependent signaling, and the negative regulator VioS, leading us to propose a model for induction of violacein production.
This work suggests a novel mechanism of interspecies interaction in which a bacterium produces an antibiotic in response to inhibition by another bacterium and supports the role of antibiotics as signal molecules.IMPORTANCE Secondary metabolites play important roles in microbial communities, but their natural functions are often unknown and may be more complex than appreciated. While compounds with antibiotic activity are often assumed to underlie microbial competition, they may alternatively act as signal molecules. In Polysaccharides , microorganisms might evolve responses to sublethal concentrations of these metabolites, either to protect themselves from inhibition or to change certain behaviors in response to the local abundance of another species. Here, we report that violacein production by C. violaceum ATCC 31532 is induced in response to hygromycin A from Streptomyces sp. 2AW, and we show that this response is dependent on inhibition of translational polypeptide elongation and a previously uncharacterized two-component regulatory system.
The breadth of the transcriptional response beyond violacein induction suggests a surprisingly complex metabolite-mediated microbe-microbe interaction and supports the hypothesis that antibiotics evolved as signal molecules. These novel insights will inform predictive models of soil community dynamics and the unintended effects of clinical antibiotic administration. Use of a stainless steel washer platform to study Acinetobacter baumannii adhesion and biofilm formation on abiotic surfaces. Acinetobacter baumannii is a frequent cause of hospital-acquired pneumonia, and has recently increased in incidence as the causative agent of severe disease in troops wounded in Afghanistan and Iraq. Clinical approaches are limited since A. baumannii strains isolated from patients are extremely resistant to current antimicrobials. A.
baumannii can survive desiccation and during outbreaks has been recovered from various sites in the patients' environment. To better understand its prevalence in hospital settings, we used a stainless steel washer surfaces. Scanning electron microscopy demonstrated that A. baumannii forms strong biofilms on stainless steel surfaces. This platform was combined with a hydroxide (XTT) reduction assay to observe the metabolic activity of bacterial cells, and to facilitate the manipulation and comparison of multiple A. mass was measured by crystal violet staining. Furthermore, the effect of commonly used disinfectants and environmental stressors on A.
baumannii biofilms and planktonic cells was compared and characterized. Biofilms on SSWs were significantly more resistant than their planktonic counterparts, providing additional evidence that may allow us to understand the high prevalence of this microbe in hospital settings. Colanic acid validate that SSWs are a simple, versatile and innovative method to study A. baumannii biofilms in vitro.
