I’ve done at lot to promote the better side of the Earth’s microorganisms and bacteria in particular. Are they grateful? I have to say no! In September 2011, I became seriously ill, only to find out that the cause of the illness was a species of bacterium called Streptococcus mitis that had set up home on my aortic heart valve. The disease is called endocarditis and is fatal unless treated but fortunately for me, it was sensitive to penicillin (a disturbingly rare vulnerability in bacteria these days). I spent a month in hospital, and after a month’s intensive antibiotic therapy the unwanted bacterial guest had disappeared. I found out after the infection, that the same bacterium had also survived for over two years on the Surveyor 3 probe on the moon , so that a little lunar outpost of earthly biology and my heart are intimately linked over many hundreds of thousands miles of space. These are photographs of the bacteria in my blood, taken by an obliging hospital microbiologist. The bacteria are the small purple chains amongst the larger red objects which are my blood cells.
The spacecraft Voyager 1 has just arrived at the most distant part of space that can be considered part of our solar system and which NASA has described as “a magnetic highway for charged particles”. This font, using bioluminescent bacteria, was made in my lab by artist, Anna Garforth. The neat font of the artist though has now been embellished and given apparent motion by bacterial activity, so that the edges of the letters appear to have been ablated off into space, and as if they has been exposed to some unseen yet powerful stream of charged particles.
A clear night sky filled with stars and constellations that shimmer with their own haunting luminescence? No. An agar plate containing many hundreds of microcolonies of bioluminescent bacteria. There is a subtle juxtaposition here, the stars, defined by the inflexible physical constants of the Universe, seemingly timeless and permanent familiars in our night skies, represented with the mutable and ephemeral phenomenon that is biology.
It is not generally widely known, but bacteria possess complex chemical communication systems that endow them with a kind of social intelligence. In the simplest sense they are able to signal their presence to other related bacteria and through this census-taking, ensure that their communities express only specific functions at particular population densities. These systems also allow bacterial communities to vote on issues affecting the entire population, and allow bacteria to function as multi-cellular organisms.
Chromobacterium violaceum is a common soil bacterium that produces striking purple colonies. In relation to the concept above, the expression of this colour is dependent on bacterial communication so that when a small number of bacteria are present it will be white but it turns purple when it receives a communication from other bacteria. When it grows in colonies, individual bacteria of these species are continually sending and receiving signals and consequently the colony will be purple. I have a modified version of this bacterium (CV026) that is effectively mute. It can receive chemical communication signals and respond to them, but cannot send them, so that it will only turns purple if it detects a communication signal from another bacterium. In this sense, it is a unique sensor for bacterial communication giving a striking and direct visualization of this phenomenon. In these, images the vertical streak is the reporter strain CV026 which in the absence of signals from other bacteria should be white. However, the horizontal streak which is the bacterium Erwinia cartovora, has produced signal molecules, and these have diffused through the media to be recognised by CV026 which has turned purple in response. This is just a test and proof of concept. Further explorations will follow soon.
A single ant cannot be considered to be “intelligent”, but when many interact as part of a colony, intelligence arises as an emergent property of their collective communication. Within the colony, each ant follows very simple rules, and although there is no centralized control structure dictating how individual ants should behave, interactions between ants lead to the emergence of an “intelligent” global behaviour. Thus, whilst the ant colony exhibits what might be called swarm intelligence, individual ants are completely unaware of this. In this sense, an ant colony is similar to a human brain where the many neurons, each of which can only perform a limited number of processes, combine to give intelligence and consciousness. Here I developed a novel process which uses in situ fluorescent tagging to plot the accumulated footfall of the many thousands of ants within a colony so that its emergent collective intelligence is revealed. In future, I plan to selectively place food sources, so that the ants might draw figures as a child would complete a dot-to-dot picture.
This is a little exploratory excursion away from the world of microbes, which challenges the way that we perceive familiar life forms. The pigments that give flowers and vegetables their striking colours are generally exquisitely sensitive to the environment around them so that small changes in pH (acidity or alkalinity),or the presence or absence of metal ions dramatically affects their colour. In essence then, you can take a naturally coloured flower or vegetable, and dramatically change its colour simply by changing environmental conditions within the plant in situ. No paints or dyes were used here, just subtle and induced alterations in plant biochemistry. Here, I’ve tailored the process so that the plants reveal hidden messages about their purpose.
This is a little exploratory excursion away from the world of microbes, which challenges the way that we perceive familiar life forms. The pigments that give flowers and vegetables their striking colours are generally exquisitely sensitive to the environment around them so that small changes in pH (acidity or alkalinity),or the presence or absence of metal ions dramatically affects their colour. In essence then, you can take a naturally coloured flower or vegetable, and dramatically change its colour simply by changing environmental conditions within the plant in situ. No paints or dyes were used here, just subtle and induced alterations in plant biochemistry.