Why mechanical noses are so clever

there's something in the air and we don't know what it is or how much of it there is but we do know that it makes people sick sometimes I'm talking about bio aerosols a bio aerosol is just a tiny floating thing of biological origin you're making bio aerosols right now like in the air that you breathe there will be tiny droplets of water that contain fragments of bacteria or dead lung cells your skin is producing bio aerosols all the time if you shuffle across your carpet you'll kick up plumes of bio aerosol one gross consequence of the human production of bio aerosol is that we get inside each other like next time you're in an interview scenario just be aware that you're breathing the interviewer in and the interviewer is breathing you in and when you leave the interview you'll take some of the interviewer with you and you will leave some of yourself inside the interviewer by the way that is not a good answer to the question why is your greatest weakness if anything is a good example of value integrate well with a team I apologize for putting that image in your head but it's probably best just not to think about it because unless the person you're exchanging bio aerosols with has an airborne infection you'll probably be fine in fact bio aerosols have been around in the environment through the entirety of human evolutionary history for example it's how mold works mold works by being everywhere all the time every breath that you take contains mold spores so it makes sense that we've evolved the ability to deal with that sort of thing but the modern industrial environment that your lungs find themselves in contains a lot more bio aerosols than in our evolutionary history so the question is is there now too much of this stuff well the first thing we need to do is characterize it we don't really know what it is is in Colbeck professor of environmental science at Essex University not much is known about biological particles in the environment so we are trying to come up with ways to measure biological particles or bio aerosols as we call them the old microbiology approach would be to take a sample on the air using a filter and then we would grow the microorganisms and and count them and identify so we have to take the sample back to the lab and we have to do lots of complicated tests that takes days that was Chantel professor of bio at Cranfield University it's not just that this process is slow it's also limited in terms of what it can show you anything that's already dead isn't going to grow in your petri dish it's quite laborious even to produce quite small data sets that are just snapshots in time can we come up with a sensor that could detect bio aerosol in real time the answer is yes but it's expensive like the machine that Shawn's been using to investigate this it's amazing it draws air into itself when it draws the air through a little tube and crossing that tube is a laser beam so if a particle crosses the laser beam then it's gonna temporarily reduce the brightness of the laser beam that can be detected and it's like a switch that turns on something further down it turns on an ultraviolet flash so this part to a carries on gets flashed with ultraviolet light we know that a lot of biological matter fluoresce is it it just does it automatically you know you don't have to stay in it or anything like that for essence is just when you shine ultraviolet light on something that thing absorbs the ultraviolet light but it then emits something else it emits other wavelengths of light in a characteristic way so you can take that emission spectrum and compare it to a database of known things you say oh that was pollen that came through now in fact it was this specific pollen there can be hundreds of these particles going through every second so this is a device that can measure a lot a lot of particular if you wanted to get really forensic and analyze the DNA that's floating around you to sequence the genes that are in the air you might start with machine called a Coriolis air sampler if you think the Dyson cyclone yeah it's basically the same principle as that so the air comes in and as it speeds up its but it circles around it's a cyclone and a spinning air pushes on some liquid that's at the bottom so the liquid starts to spin and it gets pushed against the walls of the cone-shaped flask and just like a Dyson it acts like a centrifuge so anything heavier than air so all the bio aerosols are flung out to the sides where they merge with the liquid so you run the machine for a while until you've got loads of these particles swimming around in the liquid you take that liquid and you try and sequence the DNA that's inside it here's Rob Ferguson a postdoc at the University of Essex so we essentially we just collect all the bacteria from the air and the onion we mash them up and we release the DNA and then we use that DNA to identify what is there and how much there is of it this is where metagenomics comes in and messaging omics is amazing imagine it you've got all these fragments of DNA which I'm representing here as strips of paper with HTC's and G's written on them in reality these would be in a computer and you notice that the end of one fragment of DNA matches the beginning of another fragment of DNA and you suppose that these two fragments of DNA have come from two copies of the same organism and that one is just shifted slightly further along on the genome so you take them together and now you have a much longer fragment of DNA and then you notice that the end of that matches the beginning of another fragment of DNA so you add that on and you keep going and your fragment of DNA grows and grows and grows until you have a whole gene and so now you know that the gene for say antibiotic resistance is floating around in the air so there must be organisms in the community that have that gene and if you keep going maybe you could sequence whole genomes you could figure out the organisms that are generating these bio aerosols or perhaps are these bio aerosols in reality it's not done with strips of paper these fragments of DNA are stored in a computer and it's not you doing the search for matches is the computer I'm oversimplifying process like I say that a lot but like one sensing which is more complicated is that DNA loves to repeat itself so you might find a match at the end of this fragment at the beginning of this fragment you want to put them together but actually the only reason they match is because that bit of DNA loves to copy itself so it's all over the place and you get a false positive and so like so many things in genetics it becomes a game of statistics like you have millions of these fragments so what you end up with is statistical confidence like I'm confident that this is a gene or a genome because I have multiple overlapping fragments that corroborate each other so we've got these amazing machines but where do we put them we're interested in compositing because it's almost the perfect source of bio aerosol emission they receive a lot of waste organic material so things like the clippings from the lawn the stuff you put in the green bin okay exactly and they chop it up into into small pieces pile it up into a big pile which is called a windrow you've made this big biological reactor and it's in the form of quite a dry material and and the as you produce the compost you have to agitate it as you can imagine under those conditions it's easy for this material just to fly up fly away into the wind why worry about these additional emissions particulate matter in general in elevated amounts it's potentially a hazard to human health there's a potential risk of infection the second reason is that there are there are certain chemicals that can be emitted these chemicals are component parts of the cells of some of the organisms that can cause inflammatory reactions here's an important question though how do we know that these things cause harm like do we test on humans I mean we do test things on humans but it's better not to if we can avoid it and one approach is to use what they call a a cell model which is basically where you take cells out of a body usually a human body when they move me other animal and you try to grow those cells outside of the body and then test on that so in this case you're taking lung cells in particular macrophages and epithelial cells the macrophage are looking out for trouble and when they see trouble they you know they're waving a flag and then the epithelial cells are then responding to that so there's a complicated array of chemicals that these cells produce when they're stressed a quick aside one of the ways we currently detect fragments of bacterial membrane these endotoxins is with the blood of horseshoe crabs which happens to be blue you collect a load of horseshoe crabs you drain some of their blood you release them back into the water hopefully they stay alive and you break open the blood cells and inside are these chemicals that react with endotoxins they coagulate around the endotoxins and that's a result that you can easily observe so that's why we use horseshoe crab blood for that purpose so there you go the farming of blue horseshoe crab blood is big business our vision is that our very expensive sensor could be converted through the data that we're collecting to be a really inexpensive one you could have a ring of these sensors around your site that would take into account things like things like changing wind direction or different distances from the site so we could see you know the extent to which any emissions can be seen at different different distances we're very interested in the fact that we can run these detectors all of the time 24/7 so if we found that in general 90% of the day emissions are low but there's this humongous peak associated with a particular activity we've certainly started to homed in on that the most important factors there's the shredding of the source material mostly it's the turning of the compost heaps so with these new techniques we're already starting to see maybe things that we should change but what would those changes look like so there could be chain in machineries that could could be advocated that could be doing it at certain times of the day or in certain wind conditions there are ways of compost doing outdoor composting that don't involve turning the waste so things like a false narration you could even move the entire composting process indoors and install air filters and things like that but obviously that's a hugely expensive thing to do and it will push up the price of compost and similarly with the housing of animals you can take steps to reduce bio aerosol emissions from the housing of livestock but it costs money so this isn't just a scientific challenge it's kind of a political one as well like you have to ask the question are you willing to pay more for your food so that people living near composting sites can have a better quality of life so that farmers are less likely to contract airborne diseases and I suppose any good person would say yeah I'll pay more for my chicken nuggets but it kind of doesn't work like that you know it's it's it's a good example of an externality cost which is a really interesting subject beyond the scope of this video but you know how do you take an externality costum and bring it back into the machinery of capitalism it's a big subject you know it's about legislation essentially and is that something that we have the political will to do who knows you might be wondering why there are two locations in this video it's because I moved studio halfway through filming so this is the new studio here this isn't even the main shot that I'll be using in the new studio probably I'll be doing like a wider shot that starts over there I set this one up as a kind of like hey you know let's talk let's you know sit down and and I've got a wider lens as well - yeah it's all going on yeah that's it so that answers that question that this video is the third and final video in the series commissioned by the Eden Project with funding from the National Environment Research Council National Environmental Council also funded Sean tills research and Ian Kohl Beck's research you go that's it hope you enjoyed the video if you did don't forget to hit subscribe maybe think about supporting me on patreon and I will see you next time [Music] you

Channel: Steve Mould

Views: 521,537

Keywords: Explained, Understand, metagenomics, wibs, sibs, endotoxins, dna, gene, genome, bacteria, virus, lungs

Id: DnOGtxZhBQo

Length: 13min 37sec (817 seconds)

Published: Fri Nov 29 2019