Gram-negative bacteria such as EHEC enter their prey and deploy syringe-like weapons called type III secretion systems (T3SS) that inject proteins into the epithelial cells to promote reorganization of the the cytoskeleton into pedestals that act as docking stations for the bacteria to adhere to the cells.
Both pedestal and T3SS formation demand rapid activation and precise coordination of a large number of bacterial genes co-opted from a pathogenicity island called the locus of enterocytes effacement (LEE) which Charley Gruber, Vanessa Sperandio and their colleagues at the University of Texas Southwestern Medical School in Dallas recently discovered is orchestrated by two sRNAs known as GlmY and GlmZ.
"Our data reveal two previously unknown mechanisms of actions for these sRNAs," Sperandio says. "Working together GlmY and GlmZ cleave the transcript between espJ and espFu genes enabling translation of EspFu, a protein important for efficient mammalian-cell invasion, and also destabilize the LEE 4 and 5 transcripts thus fine tuning LEE gene expression."
"Destabilization of LEE is especially important for two reasons first, it permits the differential expression of various genes encoded within the same cluster and second, it ensures that the bacteria are forming optimal pedestal levels on epithelial cells during infection," according to Sperandio. Thus, these researchers propose that these sRNAs are responsible for the dynamic rewiring of the bacterial complex machineries that enable infection.
"This is a very important contribution to the field particularly because it shows that things are more complicated than they initially appeared," comments Petr G. Leiman at École Polytechnique Fédérale de Lausanne in Switzerland. "Studies involving sRNA are tricky and require many controls which this paper appears to present in full, thus making the Sperandio team's work very significant."
"The horizontal acquisitions of pathogenicity islands [such as LEE] with their added virulence genes enable bacteria to exploit additional niches and new hosts," explains Sperandio. "Our results suggest that the interplay between ancient and recent evolutionary acquisitions shaped the EHEC we're dealing with today," Gruber adds. However, the evolution is ongoing and as the Red Queen in Alice in Wonderland so famously said, we have to race ahead just to keep up.
mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.
The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.
Jim Sliwa | EurekAlert!
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy