Archive for February 2012
Today I had a meeting with my boss, who told me about a great talk he’d been to by Professor Angela Belcher, from Massachusetts Institute of Technology. In it, she decribed using viruses to make energy generating devices, such as solar panels. Luckily, she gave the same talk at a TEDx event, which I’ve posted here. It gets interesting (from a microbiologist’s perspective) around six minutes in. At the very end are some working examples of what she’s talking about. Although it’s still very early days, I really do think this is rather exciting!
Neisseria meningitidis is a very nasty bug that can cause life-threatening bacterial meningitis; however, many people have the bacteria living harmlessly in their nasopharynx (the area at the back of your nose). The problems begin when the bacteria enter the bloodstream, after which rapid disease progression is likely. Even if it’s not fatal, meningitis can have serious consequences, including deafness or limb amputation. The specific warning signs that can help you identify a N. meningitidis infection are definitely worth a read.
The bacterium is not only nasty but also very crafty. I’ve been reading a paper from PLoS ONE that explains how it can evade being destroyed by macrophages, the ‘first line of defence’ for the body’s immune system. These immune cells engulf invading bacteria through a process known as phagocytosis. The bacteria are then broken down inside the macrophage using a series of enzymes and toxic molecules, and the broken fragments of microbe are passed on to specialised immune cells that attack any remaining bacteria.
Stopping the macrophages doing their job is an important step for an invading pathogen. Some bacteria, such as Mycobacterium tuberculosis, do this by preventing the macrophages breaking them down. They get engulfed, but they just stay dormant and hide within the immune cells until they’re ready to emerge and cause the tuberculosis disease. N. meningitidis has a very different tactic: it makes the macrophages commit suicide. The proper name for this is apoptosis, or ‘programmed cell death’, a very important cellular pathway that usually happens in a highly regulated manner (you don’t want your cells dying for no reason).
Streptomyces are weird and wonderful, even among the Bacteria (and this is a kingdom not short on oddities). They look and grow like fungi but are 1000 times smaller. That characteristic earthy smell you get walking in the countryside? That’s made by Streptomyces bacteria. They also make about 60 per cent of all the antibiotics and anticancer drugs that we use clinically, in addition to numerous immunosuppressants and antiparasitic drugs that helped to revolutionise medicine in the last century. In other words, Streptomyces are very friendly, very useful bacteria.