microbelog

blogging the latest developments in microbiology

Archive for August 2012

Drug resistance and persistence in Mycobacterium tuberculosis

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ResearchBlogging.orgAs we’ve discussed before, Mycobacterium tuberculosis is the major cause of tuberculosis, a disease that has plagued humans for millennia. The oldest recorded case of TB is in a 500 000-year-old fossil of Homo erectus. Despite the best efforts of modern medicine, we have so far failed in our fight against this disease, which kills up to two million people every year.

The problem is that M. tuberculosis infections are both hard to detect and hard to treat. Mycobacteria have a waxy coating of fats called mycolic acids that make them naturally resistant to many antibiotics and helps them hide inside human immune cells. Because the immune system can’t attack itself, this is a pretty ingenious hiding place. It typically takes six months of multidrug therapy to cure an active TB infection and nine months to kill a latent infection (that is, the TB cells that are hiding). Some of the cells that are hiding are known as ‘persisters’, and it’s these cells that take longer to kill in a latent infection.

In a recent study, scientists developed a new way to study persister cells in the lab. They found that in a large collection (or population) of TB cells, a small number form a distinct subgroup of persisters. Weirdly, despite all the cells being genetically identical, the persisters are more resistant to antibiotics than all the other normal TB cells.

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Written by microbelog

21/08/2012 at 10:00 am

Getting to the roots of the problem.

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ResearchBlogging.org

With the global population approaching seven billion and showing no sign of slowing, it’s not surprising that governments are worried about food security. A future without genetically modified crops now seems impossible.

In one of the more exciting genetic modification projects, scientists at the John Innes Centre in Norwich are trying to engineer wheat that can produce its own fertiliser. There is also growing interest in understanding the role of soils and soil microbes in promoting plant growth, and we’ve written before about the role of antibiotic-producing bacteria in disease-suppressive soils.

Two recent high-profile papers report a more detailed analysis of the microbiomes found in the roots and rhizosphere (the soil touching the roots) of the model weed Arabidopsis. Both studies found that the phylum Actinobacteria was one of the three most dominant groups in plant roots, and most of these were Streptomyces bacteria (streptomycetes).

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Written by microbelog

14/08/2012 at 10:00 am

Posted in Symbiosis

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Editorial: Standing out from the crowd

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Who decides which research should be funded? What are the flaws in the process? In this editorial, Matt Hutchings wonders if there might be a better way.

We scientists like to joke (or rather, complain) that applying for government funding is a bit like playing the lottery: winning is mostly luck. Often there is no rhyme nor reason that one grant application is funded while another isn’t, it ultimately depends on who reviews it, whether they like it and whether it fits with the strategic priorities dictated by the government. This is taxpayers’ money after all and the government don’t like to take risks with it for something as apparently unimportant as science. As Professor Brian Cox pointed out recently, our government spent more on bailing out the banks than they have spent on research funding “since Jesus”.

According to UK research council criteria, in order to be funded, the research should address issues that are relevant to the public, or perhaps more cynically, research that fits in with the current government’s election promises. In biology (our field) these relevant issues include: healthy ageing, food security and bioenergy, which can mean that important research areas are overlooked (for example, the research councils don’t fund research aimed at discovering new antibiotics).

More of a problem is that all proposed research projects must have a guaranteed “impact” (the new buzz word), which usually means publishing highly-cited articles in top tier journals, exploiting research to make money and communicating that science to inspire the general public (outreach).

This all seems reasonable given the amount of taxpayers’ money at stake, but as any scientist will tell you, funding research that guarantees results is unlikely to lead to any major discoveries. This is usually because the applicant has: (a) done the research already and knows the results (but isn’t telling the research council); or (b) is pretty much certain of what they’ll discover. What we need, and what has made the UK the most successful research nation on Earth over the last 450 years, is additional funding for blue skies research. This is the research that is perhaps slightly off the wall, but occasionally leads to a very important discovery.

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Written by microbelog

09/08/2012 at 4:09 pm

Posted in Posts

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