Cis-2-dodecenoic acid signal modulates virulence of Pseudomonas aeruginosa through interference with quorum sensing systems and T3SS.

Background: Cis-2-dodecenoic acid (BDSF) is well known for its important functions in intraspecies signaling in Burkholderia cenocepacia. Previous work has also established an important role of BDSF in interspecies and inter-kingdom communications. It was identified that BDSF modulates virulence of Pseudomonas aeruginosa.

How Mycobacterium tuberculosis goes to sleep: the dormancy survival regulator DosR a decade later.

With 2 million deaths per year, TB remains the most significant bacterial killer. The long duration of chemotherapy and the large pool of latently infected people represent challenges in disease control. To develop drugs that effectively eradicate latent infection and shorten treatment duration, the pathophysiology of the causative agent Mycobacterium tuberculosis needs to be understood.

Differential modulation of Burkholderia cenocepacia virulence and energy metabolism by the quorum-sensing signal BDSF and its synthase.

Burkholderia cenocepacia produces the molecule cis-2-dodecenoic acid (BDSF), which was previously shown to play a role in antagonism against the fungal pathogen Candida albicans by interfering with its morphological transition. In this study, we show that production of BDSF is under stringent transcriptional control and the molecule accumulates in a cell density-dependent manner, typically found with quorum-sensing (QS) signals. B.

Co-regulation of Xanthomonas campestris virulence by quorum sensing and a novel two-component regulatory system RavS/RavR.

Xanthomonas campestris pv. campestris (Xcc) is known to regulate virulence through a quorum-sensing mechanism. Detection of the quorum-sensing signal DSF by sensor RpfC leads to activation of the response regulator RpfG, which influences virulence by degrading cyclic-di-GMP and by subsequent increasing expression of the global regulator Clp.

Recombinase-based reporter system and antisense technology to study gene expression and essentiality in hypoxic nonreplicating mycobacteria.

The study of the mechanisms used by Mycobacterium tuberculosis to survive in the absence of growth is hampered by the absence of appropriate genetic tools. Here, we report two strategies, a recombinase-based reporter system and an antisense technology, to study gene expression and essentiality in hypoxic nonreplicating mycobacteria. The recombinase-based reporter system relies on the resolution of an antibiotic marker flanked by the gammadelta-res sites.

A novel DSF-like signal from Burkholderia cenocepacia interferes with Candida albicans morphological transition.

In addition to producing lethal antibiotics, microorganisms may also use a new form of antagonistic mechanism in which signal molecules are exported to influence the gene expression and hence the ecological competence of their competitors. We report here the isolation and characterization of a novel signaling molecule, cis-2-dodecenoic acid (BDSF), from Burkholderia cenocepacia. BDSF is structurally similar to the diffusible signal factor (DSF) that is produced by the RpfF enzyme of Xanthomonas campestris.

Apparent growth phase-dependent phosphorylation of malonyl coenzyme A:acyl carrier protein transacylase (MCAT), a major fatty acid synthase II component in Mycobacterium bovis BCG.

Probing protein extracts from exponentially growing and stationary phase cultures of Mycobacterium bovis BCG with anti-phospho amino acid antibodies revealed a 31-kDa anti-phospho threonine antibody-reactive protein specific to growing culture. The corresponding protein was purified via two-dimensional gel electrophoresis and identified via mass spectrometry to be malonyl coenzyme A:acyl carrier protein transacylase (MCAT), a component of the fatty acid biosynthetic pathway. MCAT tagged with histidine reacted with anti-phospho threonine antibody and was positive in an in-gel chemical assay for phospho proteins.

Mycobacterium bovis BCG response regulator essential for hypoxic dormancy.

Obligately aerobic tubercle bacilli are capable of adapting to survive hypoxia by developing into a nonreplicating or dormant form. Dormant bacilli maintain viability for extended periods. Furthermore, they are resistant to antimycobacterials, and hence, dormancy might play a role in the persistence of tuberculosis infection despite prolonged chemotherapy.