MicrobiologyBytes

Evolution of species interactions in a biofilm community

Biofilms are spatially structured communities of microbes whose function is dependent on a complex web of symbiotic interactions. Localized interactions within these assemblages are predicted to affect the coexistence of the component species, community structure and function, but there have been few explicit empirical analyses of the evolution of interactions. Using an experimental two-species community (soil dwellers Pseudomonas putida and Acinetobacter sp.) selection in this spatially structured environment led to the evolution of an exploitative interaction. Simple mutations in the genome of one species caused it to adapt to the presence of the other, forming an intimate and specialized association. The derived community was more stable and more productive than the ancestral community. Evolution in a spatially structured environment can stabilize interactions between species, provoke marked changes in their symbiotic nature and affect community function. Nature 445: 533-536

Reversing CJD
Symptoms of prion diseases, such as the human form of mad cow disease vCJD can be reversed, at least in mice. It appears that in the early stages of prion disease, synapses are frozen rather than being destroyed immediately. Halting the expression of prion protein allows function to be restored.
Targeting Cellular Prion Protein Reverses Early Cognitive Deficits and Neurophysiological Dysfunction in Prion-Infected Mice. Neuron 53: 325-335

Worldwide Emergence of Extensively Drug-resistant Tuberculosis
Mycobacterium tuberculosis strains that are resistant to an increasing number of second-line drugs used to treat multidrug-resistant tuberculosis (MDR TB) are becoming a threat to public health worldwide. We surveyed the Network of Supranational Reference Laboratories for M. tuberculosis isolates that were resistant to second-line anti-TB drugs during 2000-2004. We defined extensively drug-resistant TB (XDR TB) as MDR TB with further resistance to more than 3 of the 6 classes of second-line drugs. Of 3,520 (19.9%) MDR TB isolates, 347 (9.9%) met criteria for XDR TB. Further investigation of population-based trends and expanded efforts to prevent drug resistance and effectively treat patients with MDR TB are crucial for protection of public health and control of TB. EID 13(3) March 2007

Clostridium difficile 1, MRSA 0

UK Health Protection Agency figures show that C. difficile infections rose by 5.5% in England during the first three quarters of 2006 to 42,625. MRSA infections fell by 5% to 3,391, but if trends continue the DoH target of halving cases by 2008 will be missed.
HPA officials said there was still much to be done to get a grip on the bugs.

Microbicides: A new frontier in HIV prevention
Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections (STIs) including HIV-1. Despite more than two decades of HIV-1 vaccine research, there is still no efficacious HIV-1 vaccine, and the scientific community appears skeptical about the short or long-term feasibility of developing a vaccine that has the ability to induce sterilizing immunity against HIV-1. In this setting, microbicide research has gathered momentum. Currently, 16 candidate microbicides are in clinical development and five products are being evaluated in large-scale Phase 2B/3 effectiveness studies. Initial data from these trials will be available within the next 2-3 years, and it is feasible that there could be one or more licensed microbicides by the end of the decade. The first generation of surfactant microbicides had a non-specific mechanism of action. However, subsequent candidate microbicides have been developed to target specific steps in the process of viral transmission. The purpose of this article is to provide an overview of microbicide development and an update on the candidate pipeline. McGowan I. Biologicals. 2006 34: 241-55.

But: AIDS microbicide gel trial is stopped
Clinical trials of a new drug designed to help prevent women contracting the AIDS virus have been stopped. The World Health Organisation said the drug – involving a gel known as a microbicide – did not help the women and made them more vulnerable.

This entry was posted on Friday, February 2nd, 2007 at 12:01 pm and is filed under Bacteria, Biology, Genetics, Health, HIV/AIDS, Medicine, Microbiology, Prions, Science. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.