The typical treatment for a bacterial infection: antibiotics. These life-saving chemicals have had an enormously positive impact on human health and longevity, providing treatments for diseases that once killed millions of people. The problem: antibiotics are becoming less and less useful as bacteria evolve antibiotic resistance. Diseases once thought to be a thing of the past are re-emerging with antibiotic resistant strains of bacteria causing infections. For example, the black plague, which decimated the population of Europe back in the 1300's, is re-emerging with the evolution of antibiotic strains of Yersina pestis.
Antibiotics treat bacterial infections by killing the bacteria or by inhibiting bacterial growth allowing the immune system to eliminate the invading bacterial cells. Antibiotic resistance mechanisms rapidly evolve due to the selective pressure put on bacterial populations to gain resistance. Any bacterial cell with a mutation that allows it to survive antibiotic treatment will proliferate, passing on the antibiotic resistance trait to all its descendants, resulting in a population of antibiotic-resistant cells.
Researchers at Case Western Reserve University in Cleveland, Ohio have recently tried a different approach to treating bacterial infection.
They are searching for an alternative treatment for Staphylococcus aureus infections. Methicillin-resistant S. aureus (MRSA) is a serious cause for concern due to a large number of hospital-aquired (nosocomial) infections.
Instead of using drugs to kill MRSA, they designed a drug that would simply prevent the cells from releasing the toxins that make people sick. The bacteria are not destroyed by the drug, so there isn't any selective pressure for the bacteria to evolve resistance mechanisms.
Thursday, September 30, 2010
Monday, September 27, 2010
Not a Microbiology Post - Plant Inventory Cuts Number of Recognized Plant Species by 600,000
Although this blog primarily focuses on microbiology, we are currently discussing taxonomy and systematics in class, so this blog post is related to that topic - but in the Plant Kingdom.
Many of the previously recognized plant species were described in times prior to the use of current molecular genetic tools for constructing accurate phylogenies and before the widespread availability of information technologies for maintaining an accurate list of plant species. Consequently, many plants were described more than once and given multiple distinct species names.
Efforts are now underway to create an accurate and complete inventory of all of the world's plants. To date, there have been 600,000 previously recognized plant species stricken from the list due to redundancies. It is estimated that the final list will contain only about 400,000 plant species in total.
This article illustrates some of the issues that we discusses in class - difficulties and inaccuracies related to the old system of taxonomy, and it also highlights the improvements made with modern systematics.
An accurate inventory of plant species is thought to be essential for conservation efforts.
Many of the previously recognized plant species were described in times prior to the use of current molecular genetic tools for constructing accurate phylogenies and before the widespread availability of information technologies for maintaining an accurate list of plant species. Consequently, many plants were described more than once and given multiple distinct species names.
Efforts are now underway to create an accurate and complete inventory of all of the world's plants. To date, there have been 600,000 previously recognized plant species stricken from the list due to redundancies. It is estimated that the final list will contain only about 400,000 plant species in total.
This article illustrates some of the issues that we discusses in class - difficulties and inaccuracies related to the old system of taxonomy, and it also highlights the improvements made with modern systematics.
An accurate inventory of plant species is thought to be essential for conservation efforts.
New Extremophilic Archean Species Discovered
The first topic in our microbiology class is a "survey of the microbial world" where we are touching upon the vast diversity of microbial life on Earth. Earlier this month, a new type of extremophile was found dwelling in the depths of the ocean near a deep sea hydrothermal vent. As might be expected, this barophilic and hyperthermophilic organism is from the domain Archaea. Thermococcus onnurineus is of particular interest to scientists because it is the first organism found at these light-less underwater ecosystems that have the capability of growing using formate (HCOO-) as their sole "food" source (carbon and energy source). They are thought to live symbiotically with fermentive bacteria near hydrothermal vents.
The scientists first hypothesized that T. onnurineus was capable of growth on formate after having sequenced its genome and finding genes that were known to be involved with formate metabolism. They tested the hypothesis by growing the bug up in culture conditions providing formate as the only available carbon and energy source.
Discoveries of this nature provide more insight into ongoing development of technologies for biohydrogen production (renewable energy source).
For more information, see the original paper:
Formate-driven growth coupled with H2 production, Yun Jae Kim et al., Nature 467 , 352-355 (16 September 2010).
doi:10.1038/nature09375
The scientists first hypothesized that T. onnurineus was capable of growth on formate after having sequenced its genome and finding genes that were known to be involved with formate metabolism. They tested the hypothesis by growing the bug up in culture conditions providing formate as the only available carbon and energy source.
Discoveries of this nature provide more insight into ongoing development of technologies for biohydrogen production (renewable energy source).
For more information, see the original paper:
Formate-driven growth coupled with H2 production, Yun Jae Kim et al., Nature 467 , 352-355 (16 September 2010).
doi:10.1038/nature09375
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