Microbes in your stomach may have a shocking secret as scientists have found many species of bacteria are able to produce electricity.

Scientists from University of California, Berkeley, have discovered that listeria bacteria, which contaminate food and cause listeriosis, start producing power under certain environmental conditions – such as a lack of oxygen.

If grown in a flask with electrodes inserted these species produce a measurable current and scientists are looking at ways this could be refined and exploited to generate electricity at waste treatment plants or power small electronics.

Previously the only “electrogenic” bacteria species were thought to live in harsh, mineral-rich environments like acidic mines and lake beds.

The Berkeley team found abundant examples of gangrene-causing clostridium bacteria and hospital-acquired infectious strains capable of making sparks fly.

They also found these properties in species of beneficial bacteria, like the lactobacilli which are contained in probiotic drinks for the health promoting effects and are used in yoghurt and cheese production.

“The fact that so many bugs that interact with humans, either as [disease causing] pathogens or in probiotics or in our microbiota or involved in fermentation of human products, are electrogenic – that had been missed before,” said Professor Dan Portnoy, a microbial biology expert who is one of the authors of the study published in Nature on Wednesday.

“It could tell us a lot about how these bacteria infect us or help us have a healthy gut.”

Under the skin – best of the British Heart Foundation 2018 image prize Show all 10 1 /10 Under the skin – best of the British Heart Foundation 2018 image prize Under the skin – best of the British Heart Foundation 2018 image prize Subarachnoid vessels The runner-up image came from Matt MacGregor Sharp, a PhD student at the University of Southampton. The super-high resolution image shows a normal artery at the surface of a rat’s brain and was taken with a powerful scanning electron microscope. These ‘subarachnoid vessels’ supply blood to the brain and also act like a drain to remove toxic waste products. Matt Macgregor’s team are trying to show that failure to remove waste by these vessels is one of the underlying causes of vascular dementia. The researchers took the image using a technique called ‘freeze fracture’, where tissue or cell samples are frozen and then split apart to reveal the hidden layers within the sample so they can be studied in extreme detail. Sitting above the brown brain tissue, the artery appears blue, and its surrounding layer, the pia mater, is shown in purple. Matt MacGregor Sharp, University of Southampton, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Explosive beginnings Winner: Endothelial cells line all blood vessels in the body, forming a barrier between the circulating blood and the vessel wall. They also help to protect blood vessels from damage and release important chemical messengers which help to control blood pressure. The winning researcher, Courtney Williams, is a Masters student and PhD candidate at Leeds University. Her lab are developing new ways to map the growth of new blood vessels within their surrounding landscape in 3D. Understanding the complex secrets of blood vessel formation could be harnessed to boost the regrowth of damaged blood vessels after a heart attack, and halt blood vessel growth when it’s counterproductive. Courtney Williams, Leeds University, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize A snapshot of platelet production - Reflections of Research Supporters’ Favourite This image from Abdullah Obaid Khan, a PhD student at the University of Birmingham, won the supporters’ favourite. What look like precious jewels are actually platelets forming within the bone marrow. Platelets are the smallest of our circulating blood cells with a hugely important role in preventing bleeding. However, they also play a role in the formation of clots, which can lead to heart attacks and strokes. Abdullah Obaid Khan and his team are studying rare bleeding disorders. Abdullah Obaid Khan, University of Birmingham, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Cardiac collagen web - Shortlist This colourful image shows the web-like, network of the smallest blood vessels in the heart – the microvessels. Magenta marks the outer collagen layer of the vessels; while orange marks their inner lining and blue the cell nuclei. Dr Neil Dufton, Imperial College London Dr Neil Dufton, Imperial College London, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Heart to Heart - Shortlist This piece shows four ventricles (from a mouse) arranged into the shape of the hearts four normal chambers. The researchers have used fluorescent markers to recognise certain proteins and created the image using of hundreds of images assembled together. Dr Elisa Avolio and Dr Zexu Dang, University of Bristol Dr Elisa Avolio and Dr Zexu Dang, University of Bristol, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Loving artery - Shortlist This image shows a cross section of an artery and the different layers which make up the artery wall. Affiliate Professor Silvia Lacchini, University of Glasgow Silvia Lacchini, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Oxidative inkblot - Shortlist This colour explosion shows one of the culprits in cardiovascular disease – an enzyme called NADPH oxidase. The enzyme is considered ‘Janus faced’ because it is important in health, as well as disease. This picture shows the active enzyme in patients who have high blood pressure. Dr Livia de Lucca Camargo, University of Glasgow Dr Livia de Lucca Camargo, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Neon skeleton - Shortlist This image shows the developing blood vessel system of a two day old zebrafish embryo. The researchers used gene enhancers (the on-off switches of genes) to switch on fluorescent markers in different types of endothelial cells – the important cells which line all blood vessels. All blood vessels switch on the red marker, while the veins also switch on the green marker, resulting in yellow veins and red arteries. Dr Svanhild Nornes, University of Oxford Dr Svanhild Nornes, University of Oxford, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Calcium reef - Shortlist This image shows calcium in blood vessel cells from people who have high blood pressure and resembles Australia’s Great Barrier Reef. Dr Rheure Alves-Lopes, University of Glasgow Dr Rheure Alves-Lopes, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Budding blood vessels - Shortlist This image shows the growing blood vessels in the mouse retina. In red you can see all the blood vessels and in yellow/green you can see the blood vessels that are actively growing (a process called sprouting). PhD candidate Kira Chouliaras, University of Oxford Kira Chouliaras, University of Oxford, British Heart Foundation - Reflections of Research

Bacteria produce electricity as part of their metabolism. In humans our cells use the oxygen we breathe to drive the transfer of energy-carrying electrons locked up as sugars and other molecules in our food, fuelling every cell.

But single-celled bacteria living in low oxygen environments don’t have that option.

They have to use different chemical elements to promote this flow of electrons. In the case of electrogenic bacteria found in acid lakes or mines they are effectively breathing minerals like iron or manganese, as humans use oxygen.

As these minerals are outside the cell, the electrons have to flow throw several steps to reach them – effectively an internal current conducting electrons as they would along a copper wire.

In gut bacteria, when they’re deprived of oxygen they usually have access to an abundance of one very effective electron acceptor called flavin. This molecule is made up of vitamin B12 which is essential to the action of all of our cells and so is usually abundant in the body.

The researchers found that gut bacteria produce just as much electricity, around 500 microamps, as those using mineral exchange despite a simplified method.

“It seems that the cell structure of these bacteria and the vitamin-rich ecological niche that they occupy makes it significantly easier and more cost effective to transfer electrons out of the cell,” said Dr Sam Light, who is first author of the study.