WEBVTT - How Can an Animal Breathe Without Oxygen? 0:00:01.920 --> 0:00:06.560 Welcome to brain Stuff production of I Heart Radio. Hey, 0:00:06.640 --> 0:00:11.080 brain Stuff, Lauren Volga bomb here. Three billion years ago, 0:00:11.119 --> 0:00:14.480 things on Earth were different. For one thing, there wasn't 0:00:14.520 --> 0:00:18.439 all this oxygen all over the place. The first cyanobacteria 0:00:18.640 --> 0:00:21.279 had to figure out a way to live on volcanic 0:00:21.400 --> 0:00:26.640 carbon dioxide, water, and sunlight alone. These old timey organisms 0:00:26.720 --> 0:00:31.400 lived anaerobically, that is, without oxygen. Strangely enough, what we're 0:00:31.400 --> 0:00:34.040 breathing today is the type of atmosphere that they made 0:00:34.040 --> 0:00:38.200 possible for us. Because the byproduct that they excreted oxygen, 0:00:38.520 --> 0:00:44.440 eventually overtook Earth's atmosphere. Any remaining anaerobic organisms were forced 0:00:44.479 --> 0:00:47.240 into the oxygen less nooks and crannies of the planet 0:00:47.360 --> 0:00:52.760 and kept simple and single celled. However, when there's a rule, 0:00:52.960 --> 0:00:56.160 there's usually an exception, and a group of scientists have 0:00:56.200 --> 0:01:00.280 discovered a small parasitic niderian that is a tip of 0:01:00.280 --> 0:01:05.240 a jellyfish that apparently doesn't use oxygen to breathe. They 0:01:05.319 --> 0:01:09.360 publish their findings in the February issue of the Proceedings 0:01:09.400 --> 0:01:14.039 of the National Academy of Sciences. This animal, taxonomical name 0:01:14.080 --> 0:01:17.840 Hanagaya salmon acola, is a tiny parasite with a long 0:01:17.880 --> 0:01:20.800 tail that feeds on the muscle tissue of salmon and 0:01:20.959 --> 0:01:24.759 other fish. It's a eukaryote, which just means that it's 0:01:24.760 --> 0:01:27.640 a member of a broad group of organisms that includes 0:01:27.840 --> 0:01:29.720 most of the living things that you can see with 0:01:29.760 --> 0:01:34.520 your naked eye animals, plants, fungi, et cetera. The cells 0:01:34.560 --> 0:01:37.960 of eukaryotes contain all sorts of fancy organelles that they 0:01:37.959 --> 0:01:41.920 are more primitive counterparts the prokaryotes don't have. One of 0:01:41.920 --> 0:01:45.480 those organelles is the mitochondrian, a structure that has a 0:01:45.520 --> 0:01:48.160 tiny genome all of its own, separate from the rest 0:01:48.160 --> 0:01:51.920 of the organism, and which eukaryotic cells use to produce 0:01:52.040 --> 0:01:57.000 energy with the help of oxygen. But within the larger 0:01:57.080 --> 0:02:00.880 groups that we call eukaryotes, there are a few single 0:02:00.960 --> 0:02:06.640 celled non animal species that are anaerobic. They don't have mitochondria, 0:02:06.840 --> 0:02:12.679 but rather something that scientists call mitochondrian related organelles. Annagaya 0:02:12.760 --> 0:02:17.120 salmnicola is the first animal to have this feature. It's 0:02:17.120 --> 0:02:20.240 all very strange, so how did they get this way? 0:02:20.760 --> 0:02:23.520 For the article this episode is based on how Stuff Works. 0:02:23.560 --> 0:02:27.160 Spoke with study co author Stephen Atkinson a research professor 0:02:27.200 --> 0:02:31.040 in the Department of Microbiology at Oregon State University. He said, 0:02:31.400 --> 0:02:35.600 the ancestors of Hanna Guia almost certainly had mitochondria. All 0:02:35.600 --> 0:02:39.440 its closest relatives have mitochondria, so the evolution to an 0:02:39.440 --> 0:02:43.600 anaerobic lifestyle and the loss of functional mitochondria appears to 0:02:43.639 --> 0:02:47.320 be a recent adaptation of that species alone, at least 0:02:47.360 --> 0:02:50.680 that we know of so far. In the cells of 0:02:50.760 --> 0:02:54.680 typical animals, the mitochondria use oxygen in a multi step 0:02:54.720 --> 0:02:58.920 process to create chemical energy. The research team found that 0:02:58.960 --> 0:03:02.079 this parasite has just had to adapt to an environment 0:03:02.120 --> 0:03:06.320 with very little available oxygen. Without the need for mitochondria, 0:03:06.560 --> 0:03:10.120 it lost the genetic instructions for at least several parts 0:03:10.120 --> 0:03:13.920 of the processes that use oxygen. So by losing that 0:03:14.000 --> 0:03:17.920 mitochondrial genome, the parasite saves energy by not having to 0:03:17.960 --> 0:03:22.519 copy genes for things that no longer needs. But how 0:03:22.560 --> 0:03:26.560 can it survive without oxygen in the first place, Atkinson said, 0:03:26.960 --> 0:03:30.440 we presume that it must instead absorb molecules related to 0:03:30.520 --> 0:03:33.880 energy production from the host cells, which have already done 0:03:33.919 --> 0:03:37.160 part of the processing. Stealing something from the host is 0:03:37.200 --> 0:03:42.840 fundamental to parasitism. Like many important discoveries. This finding was 0:03:42.960 --> 0:03:46.920 totally unexpected. The researchers were hoping to compare the genomes 0:03:46.920 --> 0:03:49.600 of two small parasites, but each time they tried to 0:03:49.680 --> 0:03:54.040 run that of the Hanagaya salmonicola, something was obviously very weird. 0:03:54.920 --> 0:03:58.240 Looking into it further, they found itsels contained a little 0:03:58.320 --> 0:04:01.000 empty bag where a mitochondria and might once have been. 0:04:02.360 --> 0:04:06.520 Atkinson said, this discovery has expanded our understanding of what 0:04:06.560 --> 0:04:09.480 it means to be an animal by showing that even 0:04:09.560 --> 0:04:12.320 complex life can evolve in a way to succeed in 0:04:12.440 --> 0:04:17.440 environments without oxygen. Knowing that anaerobic animals can exist alerts 0:04:17.480 --> 0:04:19.120 us to the fact that we must be on the 0:04:19.120 --> 0:04:21.800 lookout for this and other species and maybe look in 0:04:21.880 --> 0:04:25.320 anaerobic environments for animals where we never would have looked before. 0:04:26.040 --> 0:04:29.719 Specifically from mixing zoan parasite research. It means we will 0:04:29.760 --> 0:04:33.480 look for unusual or missing mitochondria in other species from 0:04:33.520 --> 0:04:37.000 now on to try and discover the connections between hosts, 0:04:37.120 --> 0:04:40.880 tissue and environment that lead to loss of mitochondrial function 0:04:41.080 --> 0:04:46.280 to take advantage of anaerobic metabolism. The discovery of anaerobic 0:04:46.320 --> 0:04:49.520 mechanisms in these parasites could also open a new avenue 0:04:49.520 --> 0:04:52.840 for treatment, as specific drugs have been used to target 0:04:52.880 --> 0:05:01.359 other anaerobic parasites. Today's episode is based on the article 0:05:01.640 --> 0:05:04.400 can you live without oxygen? This animal can on how 0:05:04.440 --> 0:05:07.680 stuffworks dot Com. Written by Jesslan Shields. Brain Stuff is 0:05:07.680 --> 0:05:09.560 a production of Our Heart Radio in partnership with how 0:05:09.560 --> 0:05:11.880 stuff works dot Com, and it's produced by Tyler Clain. 0:05:12.400 --> 0:05:15.000 Four more podcasts my heart Radio, visit the i heart 0:05:15.040 --> 0:05:17.720 Radio app, Apple Podcasts, or wherever you listen to your 0:05:17.760 --> 0:05:18.440 favorite shows.