Future gazing: growing your own battery.

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!

Benjamin Thompson

Meningitis vs the immune system: kill or be killed

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).

Everybody wants good neighbours

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.

Bioluminescent bacteria: what a way to glow

We all love living things that glow in the dark, and scientists are no exception. Roger Tsien won a Nobel Prize in 2008 for discovering and developing green fluorescent protein and – perhaps even more excitingly – evil scientists turned mice fluorescent in a recent episode of the BBC television series Sherlock.

For animals that live in the blackness of the deep ocean, a little bit of bioluminescence goes a long way. For the squid Euprymna scolopes, this bioluminescence is generated by Vibrio fischeri bacteria that live within its light organ. The light organ is incredible, and it helps to hide the squid’s silhouette. This symbiosis is a win–win situation: the bacteria get housed and fed, and the squid gets a built-in cloaking device. Free-living bacteria also generate bioluminescence – but if they’re not in a symbiotic relationship, why do they bother?

Try anything once?

For some reason, I’ve a real hankering for Japanese food at the moment. I’ve no idea why – perhaps it’s due to me going through some old photos from when I toured across the country visiting labs about ten years ago. In one of them, I’m standing underneath a large fibreglass puffer fish outside a restaurant (no, I’m not going to post it).

Puffer fish, in case you didn’t know, is quite the delicacy in many parts of Asia. In Japan, it’s known as fugu. I didn’t eat any, though. Why not? Well, the fish is one of the most poisonous animals in the world. It must be skilfully prepared, or it’s potentially lethal: a slight tingling of the lips, and it’s goodnight. Deaths are rare nowadays, but I didn’t want to take the risk. I try to avoid eating anything that might kill me (although I did once – and only once – eat a kebab).

The changing face of the invisible Arctic

Have you watched the BBC One documentary series Frozen Planet? It’s an amazing show that really highlights the changing nature of the frozen wilderness. It’s hard not to feel sorry for the Arctic polar bears as the environment they live in continues to disappear. Understandably, the programme focuses on large, impressive beasts, but I wondered what was happening at the other end of the food chain and wanted to see how microbes are coping with the changing temperature (yes, I’m an absolute scream at dinner parties).

I found a paper in PLoS One that looks at this very subject. Canadian scientists looked at how the communities of bacteria, archaea and tiny eukaryotes changed between 2003 and 2010 in the Beaufort Strait. This timeframe is significant because September 2007 saw Arctic ice shrink to a record low. This was due to the melting of ‘multiyear sea ice’ – ice that stays frozen through the summer months and contains less brine (and, therefore, is less salty) than other ice in the Arctic. In particular, the scientists looked at a layer of the sea known as the subsurface chlorophyll maxima, or SCM, which contains a high number of photosynthetic plankton.

For my day job…

A post I wrote about the phylogeny of Archaea has become one of the most popular articles on the Wellcome Trust blog in 2011. I’m as surprised as you are. That said, the science in it is super interesting – I interviewed Dr Steve Kelly, from the University of Oxford, who has published some work showing from where all eukaryotic cells may have evolved.

You can read the it here.

A very happy New Year from Matt and I, thanks for taking the time to read our posts and we’ll be back in 2012 with lots of new stories!

Benjamin Thompson

Pathogenic fungi use plants’ proteins against them.

Fungal diseases in plants cause huge economic problems for farmers worldwide, either by reducing crop yield or by killing plants outright. These disease-causing fungi produce an array of compounds, known as ‘virulence factors’ that they use to breach plant defences. The two are locked in a constant arms race, with the plant trying to produce defences that let it stay one step ahead of the pathogen. This is often described as the Red Queen Hypothesis.

A new paper by Djamei et al. has revealed the nature of one of the virulence factors of Ustilago maydis, the fungal agent that causes maize smut. U. maydis requires live plants to survive, secreting many protein effectors that suppress the plant’s defence response and alter its metabolic pathways to suit the fungus. Most of these proteins are of unknown function.

Guest Post: Sequencing for the microbiological masses

Despite being in its relative infancy, genome sequencing (and the technologies that drive it) have become central to much of the molecular biology that we take for granted. In this guest post, Nick Tucker takes a closer look at the past, present and potential future of DNA sequencing as it becomes cheaper and more readily available.

Mining databases of microbial genomes has rapidly become a routine part of experimental work for microbiologists the world over. It must be impossible for this year’s new intake of PhD students to imagine a world without them. But let’s reminisce for a moment, just to see how far we’ve come.

Bacterial spam mail

History dictates that Alexander Fleming will be best remembered for his discovery of penicillin, what with him winning the Nobel Prize and all. Perhaps what he should be remembered for, however, are the paintings he made on agar using different coloured bacteria. Quite why this culturally important art form never caught on is anybody’s guess.

It may have been Fleming’s strange hobby that inspired a group of scientists to go one stage further and develop an encrypted messaging system (obviously), which uses printed patterns, known as arrays, of different coloured bacteria. These bugs are coloured by the expression of genetically engineered fluorescent proteins, and the scientists in question have called the system ‘steganography by printed arrays of microbes’, or (ahem) SPAM for short…