1 00:00:00,260 --> 00:00:11,869 [Music] 2 00:00:18,179 --> 00:00:15,150 my name is Larry McCarthy and I'm a PhD 3 00:00:21,870 --> 00:00:18,189 student in the Schmidt lab a few Baldr 4 00:00:24,390 --> 00:00:21,880 and our lab studies microbial diversity 5 00:00:28,109 --> 00:00:24,400 and communities at extreme high 6 00:00:30,750 --> 00:00:28,119 elevation and today I will talk to you 7 00:00:33,270 --> 00:00:30,760 about how some of these environments in 8 00:00:35,220 --> 00:00:33,280 particular the atacama volcanoes can be 9 00:00:37,710 --> 00:00:35,230 represented and can represent some of 10 00:00:39,690 --> 00:00:37,720 the best martian analogs here on earth 11 00:00:42,889 --> 00:00:39,700 and tell you about what we have found 12 00:00:45,380 --> 00:00:42,899 out of the life existing there through 13 00:00:48,060 --> 00:00:45,390 different approaches that go from 14 00:00:53,549 --> 00:00:48,070 microbial diversity community analysis 15 00:00:55,590 --> 00:00:53,559 to genomics so terrestrial analogs of 16 00:00:58,310 --> 00:00:55,600 the Martian surface of her insights on 17 00:01:01,560 --> 00:00:58,320 its available Abbot's ability potential 18 00:01:03,299 --> 00:01:01,570 and in the last decade extreme 19 00:01:05,580 --> 00:01:03,309 environments that were thought to be 20 00:01:07,800 --> 00:01:05,590 devoid of life have actually been shown 21 00:01:10,490 --> 00:01:07,810 to be populated by various levels of 22 00:01:13,140 --> 00:01:10,500 biodiversity supporting the notion that 23 00:01:16,649 --> 00:01:13,150 pretty much at least on earth the life 24 00:01:19,850 --> 00:01:16,659 always finds a way however we know that 25 00:01:21,770 --> 00:01:19,860 no analogue is a perfect lips or the 26 00:01:25,770 --> 00:01:21,780 representation of the Martian surface 27 00:01:28,710 --> 00:01:25,780 but we argue that high elevation cold 28 00:01:32,910 --> 00:01:28,720 desert soils are some of the best model 29 00:01:36,260 --> 00:01:32,920 systems for life on Mars surface so this 30 00:01:39,510 --> 00:01:36,270 type of Hilah vation cold deserts occur 31 00:01:41,580 --> 00:01:39,520 worldwide on mountain ranges between the 32 00:01:43,560 --> 00:01:41,590 upper boundary of land distribution and 33 00:01:45,390 --> 00:01:43,570 the lower limit of permanently 34 00:01:47,219 --> 00:01:45,400 ice-covered regions so that's 35 00:01:49,380 --> 00:01:47,229 represented in this picture where we 36 00:01:54,030 --> 00:01:49,390 have a relationship between latitude and 37 00:01:56,910 --> 00:01:54,040 elevation and they would occur in they 38 00:01:58,859 --> 00:01:56,920 would occur in this brown belt worldwide 39 00:02:01,620 --> 00:01:58,869 and some of the highest peaks are also 40 00:02:03,749 --> 00:02:01,630 shown as a reference so among these 41 00:02:05,999 --> 00:02:03,759 environments the most extreme are 42 00:02:07,800 --> 00:02:06,009 probably occur in the Dry Valleys and 43 00:02:11,000 --> 00:02:07,810 slope of the Andean volcanoes 44 00:02:13,830 --> 00:02:11,010 above 5000 meters of elevation so 45 00:02:16,589 --> 00:02:13,840 conditions that life has to face there 46 00:02:18,010 --> 00:02:16,599 is even more extreme that where we will 47 00:02:21,850 --> 00:02:18,020 find in the Attic 48 00:02:23,590 --> 00:02:21,860 desert so microbial life has to come to 49 00:02:26,220 --> 00:02:23,600 cope with a complex interplay of 50 00:02:29,260 --> 00:02:26,230 parameters that go from high UV flux 51 00:02:31,720 --> 00:02:29,270 extreme 3 or no freeze-thaw cycles low 52 00:02:34,270 --> 00:02:31,730 atmospheric pressure and pH and soils 53 00:02:38,380 --> 00:02:34,280 and an extremely low nutrient content 54 00:02:41,350 --> 00:02:38,390 and water activity so the highest of 55 00:02:43,810 --> 00:02:41,360 this volcanoes is volcano yakko which is 56 00:02:46,540 --> 00:02:43,820 also the highest archaeological site on 57 00:02:48,610 --> 00:02:46,550 earth so close to a summit some of the 58 00:02:50,560 --> 00:02:48,620 best the naturally preserved mummies 59 00:02:52,630 --> 00:02:50,570 have been found and they're really 60 00:02:54,130 --> 00:02:52,640 interesting on a microbiology 61 00:02:57,010 --> 00:02:54,140 perspective because they pretty much 62 00:02:59,340 --> 00:02:57,020 show no sign of decay after being very 63 00:03:03,240 --> 00:02:59,350 there for more than 500 years without 64 00:03:06,670 --> 00:03:03,250 preserving chemicals so this inspired 65 00:03:09,280 --> 00:03:06,680 our first expeditions to decide to 66 00:03:14,050 --> 00:03:09,290 address questions about the cold dry 67 00:03:16,810 --> 00:03:14,060 limits to life on Earth so a first 68 00:03:18,670 --> 00:03:16,820 analysis of the soils have shown that 69 00:03:21,700 --> 00:03:18,680 there's nearly undetectable levels of 70 00:03:23,770 --> 00:03:21,710 water organic carbon microbial biomass 71 00:03:25,900 --> 00:03:23,780 and the extracellular enzyme activity 72 00:03:28,540 --> 00:03:25,910 and it seems like only a very limited 73 00:03:31,330 --> 00:03:28,550 spectrum of bacterial and fungal images 74 00:03:33,430 --> 00:03:31,340 have been able to overcome the harshness 75 00:03:37,120 --> 00:03:33,440 of this environment and possibly 76 00:03:39,790 --> 00:03:37,130 functioning in the situ so when we look 77 00:03:42,220 --> 00:03:39,800 at the distribution of like the main 78 00:03:44,260 --> 00:03:42,230 phyla that we have in this environment 79 00:03:47,710 --> 00:03:44,270 we see that they're completely dominated 80 00:03:51,340 --> 00:03:47,720 by Laura flag sign up here and a tina 81 00:03:53,500 --> 00:03:51,350 bacteria so we are also below the dry 82 00:03:55,690 --> 00:03:53,510 limit of a photo on social fees there's 83 00:03:59,370 --> 00:03:55,700 no photo scripts I've ever been found at 84 00:04:02,380 --> 00:03:59,380 these elevations and they're probably 85 00:04:04,150 --> 00:04:02,390 the soils that have the lowest microbial 86 00:04:05,920 --> 00:04:04,160 diversity ever reported in the 87 00:04:07,810 --> 00:04:05,930 terrestrial system especially if we 88 00:04:12,040 --> 00:04:07,820 compare it to the Dry Valleys of 89 00:04:13,930 --> 00:04:12,050 Antarctica and Himalaya there are 90 00:04:16,659 --> 00:04:13,940 however some niches that are able to 91 00:04:19,060 --> 00:04:16,669 mitigate some of this environmental 92 00:04:21,729 --> 00:04:19,070 challenges for example fumaroles on 93 00:04:24,909 --> 00:04:21,739 volcanoes are able to provide water and 94 00:04:27,610 --> 00:04:24,919 warmth and the co2 through the gassing 95 00:04:31,540 --> 00:04:27,620 and we have seen that they support some 96 00:04:34,240 --> 00:04:31,550 way more complex communities especially 97 00:04:36,280 --> 00:04:34,250 like they form uh some a very peculiar 98 00:04:39,550 --> 00:04:36,290 math structure it's really close to the 99 00:04:41,770 --> 00:04:39,560 summit and it is evident from the 100 00:04:44,200 --> 00:04:41,780 rarefaction curves of our eukaryotic 101 00:04:47,440 --> 00:04:44,210 communities the fumarole supports a much 102 00:04:50,340 --> 00:04:47,450 more diverse community compared to the 103 00:04:53,590 --> 00:04:50,350 dry soils that are just surrounding them 104 00:04:53,950 --> 00:04:53,600 another Oasis is represented by the so 105 00:04:57,460 --> 00:04:53,960 called 106 00:04:59,560 --> 00:04:57,470 Nieves penitentes so these are ice 107 00:05:02,290 --> 00:04:59,570 structures that are pretty common uh 108 00:05:06,310 --> 00:05:02,300 along the high elevations of the Atacama 109 00:05:08,620 --> 00:05:06,320 and they periodically release meltwater 110 00:05:10,720 --> 00:05:08,630 around its soil so they're pretty much 111 00:05:12,760 --> 00:05:10,730 the only semi-permanent sources of water 112 00:05:15,250 --> 00:05:12,770 in this environment and again we've been 113 00:05:17,470 --> 00:05:15,260 able to see that they are able to 114 00:05:20,560 --> 00:05:17,480 support much richer communities and 115 00:05:23,290 --> 00:05:20,570 especially important is that we found 116 00:05:25,450 --> 00:05:23,300 photo tropes in the soils and the eye 117 00:05:27,780 --> 00:05:25,460 structures themselves compared to the 118 00:05:31,030 --> 00:05:27,790 dry soils where you would never find any 119 00:05:32,440 --> 00:05:31,040 photo troops so the photo just found our 120 00:05:34,810 --> 00:05:32,450 mainly the form of algae and 121 00:05:37,090 --> 00:05:34,820 interestingly no cyanobacteria have been 122 00:05:40,510 --> 00:05:37,100 retreated from here so it means that 123 00:05:44,170 --> 00:05:40,520 penitentes and the fumaroles are the 124 00:05:45,550 --> 00:05:44,180 only structures that allow the presence 125 00:05:47,340 --> 00:05:45,560 of photo troops in this type of 126 00:05:50,650 --> 00:05:47,350 environment 127 00:05:52,510 --> 00:05:50,660 another very harsh trait that has been 128 00:05:54,100 --> 00:05:52,520 completely under studied but it's very 129 00:05:57,070 --> 00:05:54,110 common in this high elevation 130 00:05:59,890 --> 00:05:57,080 environment is the extreme diurnal three 131 00:06:02,200 --> 00:05:59,900 cell cycle that occurs on the soils so 132 00:06:05,080 --> 00:06:02,210 as we can see temperatures can fluctuate 133 00:06:08,560 --> 00:06:05,090 starting from a - stand up to 30 degrees 134 00:06:10,810 --> 00:06:08,570 within a 24 hour cycle so daily 135 00:06:13,240 --> 00:06:10,820 temperature cycling across the freezing 136 00:06:16,600 --> 00:06:13,250 point is a key challenge for microbial 137 00:06:20,620 --> 00:06:16,610 growth and survival as it is known to 138 00:06:23,080 --> 00:06:20,630 cause multiple damages on a multiple 139 00:06:24,610 --> 00:06:23,090 level as it combines the stress of the 140 00:06:30,250 --> 00:06:24,620 cold with the reduction in water 141 00:06:32,080 --> 00:06:30,260 activity so the type of dry and cryo 142 00:06:34,870 --> 00:06:32,090 philic environments it was assumed - 143 00:06:37,240 --> 00:06:34,880 that the low biomass and diversity was 144 00:06:41,290 --> 00:06:37,250 mainly due to the lack of water however 145 00:06:42,910 --> 00:06:41,300 recent studies have challenged this by 146 00:06:44,310 --> 00:06:42,920 showing for example the nutrient 147 00:06:46,410 --> 00:06:44,320 additions in some 148 00:06:47,430 --> 00:06:46,420 periglacial soils in Peru and the 149 00:06:50,100 --> 00:06:47,440 Antarctic Dry Valleys 150 00:06:52,860 --> 00:06:50,110 have a much stronger effect than water 151 00:06:57,150 --> 00:06:52,870 additions on the community structures we 152 00:06:58,890 --> 00:06:57,160 know that microbial in that soils and 153 00:07:01,320 --> 00:06:58,900 you yaku have some of the lowest 154 00:07:04,080 --> 00:07:01,330 nutrients available so it is entirely 155 00:07:08,160 --> 00:07:04,090 possible at this point that microbial 156 00:07:09,720 --> 00:07:08,170 life happens in the soils only if when 157 00:07:11,250 --> 00:07:09,730 there is water availability also 158 00:07:14,460 --> 00:07:11,260 nutrients are available 159 00:07:16,680 --> 00:07:14,470 so given this premises I wondered how 160 00:07:20,940 --> 00:07:16,690 would these extra food communities 161 00:07:23,100 --> 00:07:20,950 respond if we partially elevated water 162 00:07:26,160 --> 00:07:23,110 and mutual limitations in this 163 00:07:29,760 --> 00:07:26,170 environment under the field the thermal 164 00:07:31,890 --> 00:07:29,770 fluctuation so we assumed that the 165 00:07:34,170 --> 00:07:31,900 communities law lay dormant for most of 166 00:07:36,750 --> 00:07:34,180 the time and only come to life pretty 167 00:07:39,900 --> 00:07:36,760 much when there are pulses of water and 168 00:07:41,850 --> 00:07:39,910 the nutrients through snowfall events 169 00:07:43,920 --> 00:07:41,860 which are pretty infrequent in this 170 00:07:46,620 --> 00:07:43,930 environment and I only ended positions 171 00:07:48,570 --> 00:07:46,630 of organic matter from the atmosphere so 172 00:07:50,790 --> 00:07:48,580 the potential for this communities under 173 00:07:53,550 --> 00:07:50,800 occasional favorable conditions remains 174 00:07:56,790 --> 00:07:53,560 completely unknown to date so what I 175 00:07:59,250 --> 00:07:56,800 decided to do was to apply experimental 176 00:08:02,280 --> 00:07:59,260 water nutrient amendments in the street 177 00:08:05,490 --> 00:08:02,290 events to soil to soil micro systems 178 00:08:08,010 --> 00:08:05,500 micro cars and subject them to the 179 00:08:12,780 --> 00:08:08,020 freeze-thaw cycles that we see in the 180 00:08:15,570 --> 00:08:12,790 field so to do that I place the some 181 00:08:18,360 --> 00:08:15,580 soils that we collected above 6000 182 00:08:20,340 --> 00:08:18,370 meters on Union yahko in a temperature 183 00:08:22,620 --> 00:08:20,350 control chamber that is able to mimic 184 00:08:25,140 --> 00:08:22,630 that fluctuation in temperature that we 185 00:08:28,500 --> 00:08:25,150 see also in the field and we had a two 186 00:08:32,459 --> 00:08:28,510 type of treatment so we had microcosm 187 00:08:36,060 --> 00:08:32,469 that were exposed to water additions to 188 00:08:39,330 --> 00:08:36,070 simulate the snowfall events and then 189 00:08:41,760 --> 00:08:39,340 three stop blast water and nutrients to 190 00:08:43,140 --> 00:08:41,770 simulate also occasional aisle in 191 00:08:47,340 --> 00:08:43,150 depositions in this soil 192 00:08:52,100 --> 00:08:47,350 I also parsed out to be cumulative 193 00:08:54,870 --> 00:08:52,110 effect of multiple watering events by 194 00:08:58,020 --> 00:08:54,880 simulating three discrete snowfall 195 00:09:00,690 --> 00:08:58,030 events we also allow 196 00:09:02,310 --> 00:09:00,700 the soils to dry up to 90% before 197 00:09:06,290 --> 00:09:02,320 applying a new water addition so that 198 00:09:08,760 --> 00:09:06,300 they would simulate pretty much the the 199 00:09:12,830 --> 00:09:08,770 moisture conditions that are normally 200 00:09:15,930 --> 00:09:12,840 found in in this environment so after 201 00:09:19,110 --> 00:09:15,940 extracting our DNA doing the sequencing 202 00:09:22,800 --> 00:09:19,120 of the main 16s and 18s of the community 203 00:09:25,350 --> 00:09:22,810 analyzing them what we saw is that the 204 00:09:27,330 --> 00:09:25,360 community was significantly changing so 205 00:09:29,340 --> 00:09:27,340 in here we have a pickup PCoIP lot of 206 00:09:33,860 --> 00:09:29,350 the bacterial community and we see how 207 00:09:36,690 --> 00:09:33,870 the community significantly changes when 208 00:09:39,420 --> 00:09:36,700 treatments are applied both if it's just 209 00:09:41,750 --> 00:09:39,430 the water addition or water plus 210 00:09:46,230 --> 00:09:41,760 nutrient additions and the community 211 00:09:50,970 --> 00:09:46,240 increases each time more with every 212 00:09:54,930 --> 00:09:50,980 addition so which organ is are actually 213 00:09:57,690 --> 00:09:54,940 allowing of this shift so we looked a 214 00:10:00,150 --> 00:09:57,700 little bit and first of all we saw that 215 00:10:02,660 --> 00:10:00,160 the there is a response to water input 216 00:10:05,579 --> 00:10:02,670 even when nutrient limitations are not 217 00:10:07,530 --> 00:10:05,589 alleviated so this may mean that water 218 00:10:10,110 --> 00:10:07,540 availability allows this try adapted 219 00:10:14,370 --> 00:10:10,120 communities to at least respond to the 220 00:10:16,500 --> 00:10:14,380 very low nutrients that are available we 221 00:10:18,960 --> 00:10:16,510 saw that one of the main orders that 222 00:10:22,020 --> 00:10:18,970 responded to multiple wiring events were 223 00:10:25,050 --> 00:10:22,030 was the Burkholder reality so this order 224 00:10:27,510 --> 00:10:25,060 is very widespread in cryo philocan 225 00:10:29,040 --> 00:10:27,520 oligotrophic environment so it may be 226 00:10:35,030 --> 00:10:29,050 able to function in situ and take 227 00:10:38,790 --> 00:10:35,040 advantage of this water and water in 228 00:10:41,400 --> 00:10:38,800 impulses we saw an increase in the 229 00:10:43,470 --> 00:10:41,410 action of mice italics especially when 230 00:10:45,960 --> 00:10:43,480 you're providing them with nutrients and 231 00:10:47,760 --> 00:10:45,970 with the first water addition there was 232 00:10:49,890 --> 00:10:47,770 an increase in chloro sort of bacteria 233 00:10:51,840 --> 00:10:49,900 so this group is interesting because it 234 00:10:53,640 --> 00:10:51,850 has a potential to do photosynthesis 235 00:10:59,130 --> 00:10:53,650 even if it's not demonstrated in our 236 00:11:00,690 --> 00:10:59,140 soil and we saw pretty much like a 237 00:11:03,420 --> 00:11:00,700 decrease in diversity 238 00:11:06,360 --> 00:11:03,430 after the third event for both type of 239 00:11:08,400 --> 00:11:06,370 treatments so this indicates probably 240 00:11:11,410 --> 00:11:08,410 that only a very minor part of the 241 00:11:13,180 --> 00:11:11,420 community would be active when 242 00:11:15,370 --> 00:11:13,190 conditions allow for that and the rest 243 00:11:18,490 --> 00:11:15,380 of the taxonomy that we see in this 244 00:11:20,290 --> 00:11:18,500 soils is probably due to just like IO in 245 00:11:23,410 --> 00:11:20,300 the position that they are dormant in 246 00:11:25,420 --> 00:11:23,420 the soil a similar pattern is shown for 247 00:11:28,510 --> 00:11:25,430 the eukaryotic community again we see 248 00:11:31,900 --> 00:11:28,520 that multiple simulated snowfall events 249 00:11:34,900 --> 00:11:31,910 and nutrient additions make the 250 00:11:38,320 --> 00:11:34,910 community change and this is especially 251 00:11:41,230 --> 00:11:38,330 more evidence for just like water 252 00:11:43,570 --> 00:11:41,240 additions and interestingly we see that 253 00:11:46,240 --> 00:11:43,580 freethought alone has an impact on the 254 00:11:49,330 --> 00:11:46,250 community as we see here our starting 255 00:11:53,410 --> 00:11:49,340 point cluster separately from our 256 00:11:55,240 --> 00:11:53,420 freeze-thaw alone treatment so it may be 257 00:11:57,100 --> 00:11:55,250 that some of this organizers are 258 00:12:01,000 --> 00:11:57,110 actually responding just to the 259 00:12:03,580 --> 00:12:01,010 FreeStore alone which microorganism 260 00:12:07,270 --> 00:12:03,590 again like a responding to this so the 261 00:12:11,470 --> 00:12:07,280 first and most interesting to us is the 262 00:12:14,140 --> 00:12:11,480 Cryptococcus so this is very relevant in 263 00:12:17,110 --> 00:12:14,150 our soil so it's one of the most 264 00:12:19,960 --> 00:12:17,120 commonly we found and we saw that it 265 00:12:22,840 --> 00:12:19,970 increases dramatically once you give the 266 00:12:25,240 --> 00:12:22,850 first water and water plus nutrient 267 00:12:27,430 --> 00:12:25,250 addition so it's possible that takes 268 00:12:31,270 --> 00:12:27,440 advantage like very fast of this water 269 00:12:33,550 --> 00:12:31,280 and nutrient impulses we see an increase 270 00:12:35,860 --> 00:12:33,560 in the thea mindsets these are other 271 00:12:38,470 --> 00:12:35,870 type of funds like they may not be as 272 00:12:40,090 --> 00:12:38,480 fast of responders but they are known to 273 00:12:42,250 --> 00:12:40,100 be well suited to low nutrient 274 00:12:45,760 --> 00:12:42,260 environments and then the most dramatic 275 00:12:48,790 --> 00:12:45,770 shift happened when just water was added 276 00:12:50,920 --> 00:12:48,800 so we get one out of truck which is like 277 00:12:53,590 --> 00:12:50,930 an algae and new cloris RC know that 278 00:12:56,380 --> 00:12:53,600 starts becoming dominant and another 279 00:12:59,110 --> 00:12:56,390 group of fans I mostly do my seeds that 280 00:13:01,470 --> 00:12:59,120 again are well known that for being able 281 00:13:03,970 --> 00:13:01,480 like to withstand a lot of stresses and 282 00:13:06,010 --> 00:13:03,980 again like in the bacteria we see a 283 00:13:09,040 --> 00:13:06,020 significant decrease in alpha diversity 284 00:13:13,330 --> 00:13:09,050 with multiple water and nutrient 285 00:13:15,100 --> 00:13:13,340 additions so we saw that a Cryptococcus 286 00:13:16,720 --> 00:13:15,110 like becomes really dominant as soon as 287 00:13:19,750 --> 00:13:16,730 like he provided with a little bit of 288 00:13:22,150 --> 00:13:19,760 water and nutrients but interestingly it 289 00:13:25,030 --> 00:13:22,160 does so even when it's just exposed the 290 00:13:27,220 --> 00:13:25,040 tooth we saw dry condition so I'm 291 00:13:29,040 --> 00:13:27,230 maybe that it's partially active when 292 00:13:32,740 --> 00:13:29,050 there's an extremely low water content 293 00:13:34,840 --> 00:13:32,750 so we isolated this organist and 294 00:13:37,990 --> 00:13:34,850 cultured it and did a phylogenetic 295 00:13:39,639 --> 00:13:38,000 analysis and we saw that it's extremely 296 00:13:42,540 --> 00:13:39,649 closely related to another 297 00:13:44,590 --> 00:13:42,550 Cryptococcus from the Dry Valleys 298 00:13:46,590 --> 00:13:44,600 Cryptococcus trade money which is up 299 00:13:50,740 --> 00:13:46,600 there were tolerant and in the lytic 300 00:13:54,610 --> 00:13:50,750 type of Easton so cryptic Hachi have 301 00:13:56,710 --> 00:13:54,620 been found like many times in many 302 00:13:58,809 --> 00:13:56,720 glacial and extreme environments and 303 00:14:00,340 --> 00:13:58,819 given its ubiquity in the south of 304 00:14:03,490 --> 00:14:00,350 environments and the ability to 305 00:14:06,040 --> 00:14:03,500 withstand three spell cycles it may be 306 00:14:09,460 --> 00:14:06,050 an important functional component of 307 00:14:12,100 --> 00:14:09,470 this environment so what I did next was 308 00:14:14,199 --> 00:14:12,110 to try and figure out if the 309 00:14:16,180 --> 00:14:14,209 Cryptococcus was not just a surviving 310 00:14:18,490 --> 00:14:16,190 but if it was actively growing under 311 00:14:20,860 --> 00:14:18,500 this condition so what I did is that I 312 00:14:22,809 --> 00:14:20,870 set up called liquid cultures of it and 313 00:14:25,410 --> 00:14:22,819 I placed them in that same thermal 314 00:14:28,749 --> 00:14:25,420 chambers that allow fluctuations and 315 00:14:32,079 --> 00:14:28,759 incredibly it was able to grow despite 316 00:14:34,870 --> 00:14:32,089 freezing a solid every night so with a 317 00:14:36,189 --> 00:14:34,880 doubling time of about two days so this 318 00:14:37,990 --> 00:14:36,199 as far as we know is the first 319 00:14:40,449 --> 00:14:38,000 demonstration of growth of an organized 320 00:14:43,360 --> 00:14:40,459 during repeated extreme free cell cycles 321 00:14:45,400 --> 00:14:43,370 and it supports even more our original 322 00:14:48,069 --> 00:14:45,410 hypothesis that it has the capacity to 323 00:14:51,340 --> 00:14:48,079 grow during this free cell cycles in the 324 00:14:53,199 --> 00:14:51,350 environment mainly doing so when there 325 00:14:55,569 --> 00:14:53,209 is higher soil moisture which is 326 00:14:59,319 --> 00:14:55,579 provided by infrequent snowstorms in 327 00:15:01,269 --> 00:14:59,329 this environment the next question that 328 00:15:02,949 --> 00:15:01,279 we want to ask is which strategies does 329 00:15:04,809 --> 00:15:02,959 they used to survive this multiple 330 00:15:06,819 --> 00:15:04,819 challenges in this life limiting 331 00:15:10,090 --> 00:15:06,829 environment and especially how does it 332 00:15:15,490 --> 00:15:10,100 cope with free-stall so our plan is to 333 00:15:18,819 --> 00:15:15,500 use a combined strategy of both genomics 334 00:15:20,500 --> 00:15:18,829 and transcriptomics to figure out which 335 00:15:22,840 --> 00:15:20,510 genes allow survival and metabolic 336 00:15:25,329 --> 00:15:22,850 activity in this organism and the to 337 00:15:27,879 --> 00:15:25,339 analyze its genome by seeing if it has 338 00:15:30,129 --> 00:15:27,889 significant deviations from its men's 339 00:15:32,530 --> 00:15:30,139 fellow counterpart so what we did was 340 00:15:36,639 --> 00:15:32,540 culturing it an optimal temperature that 341 00:15:39,080 --> 00:15:36,649 we found it to be 17 degrees and or we 342 00:15:41,750 --> 00:15:39,090 extracted total DNA 343 00:15:59,840 --> 00:15:41,760 sequence it and started its general 344 00:16:13,370 --> 00:15:59,850 assembly and on rotation I'm sorry okay 345 00:16:15,590 --> 00:16:13,380 I'm merely done okay yeah so very 346 00:16:20,000 --> 00:16:15,600 briefly like the jeans that we're gonna 347 00:16:23,180 --> 00:16:20,010 look for our metabolic gene so since we 348 00:16:25,220 --> 00:16:23,190 suspect this to be like versatile 349 00:16:27,230 --> 00:16:25,230 opportunity that is able to take 350 00:16:29,780 --> 00:16:27,240 advantage of whatever the atmosphere 351 00:16:36,520 --> 00:16:29,790 brings it on this high elevation we 352 00:16:39,080 --> 00:16:36,530 expected to have many degrading pathways 353 00:16:41,150 --> 00:16:39,090 we will look at genes associated with 354 00:16:42,920 --> 00:16:41,160 oxidant and the somatic stress we still 355 00:16:45,530 --> 00:16:42,930 don't know what kind of like stress 356 00:16:49,640 --> 00:16:45,540 signal is generated with with pre cell 357 00:16:51,680 --> 00:16:49,650 cycle cold adaptation genes genes 358 00:16:54,130 --> 00:16:51,690 necessary to complete meiosis to see if 359 00:16:57,560 --> 00:16:54,140 it's able to do with sexual reproduction 360 00:16:59,570 --> 00:16:57,570 and then G's that allow through with 361 00:17:02,710 --> 00:16:59,580 standfast temperature switches for 362 00:17:05,990 --> 00:17:02,720 example related to membrane fluidity and 363 00:17:07,730 --> 00:17:06,000 genes that allow it to live at water at 364 00:17:11,570 --> 00:17:07,740 a low water activity so we have to keep 365 00:17:15,170 --> 00:17:11,580 in mind that when there's low in this a 366 00:17:16,670 --> 00:17:15,180 freezing environment there is extremely 367 00:17:18,350 --> 00:17:16,680 low water activity so there are like 368 00:17:21,410 --> 00:17:18,360 very similar to hyper saline 369 00:17:25,120 --> 00:17:21,420 environments and the last step we'll do 370 00:17:27,980 --> 00:17:25,130 to do a transcriptomic analysis of 371 00:17:31,820 --> 00:17:27,990 specific time points within that thermal 372 00:17:34,040 --> 00:17:31,830 cycle so the idea is to grow it and 373 00:17:36,920 --> 00:17:34,050 sample at a different temperatures 374 00:17:40,030 --> 00:17:36,930 within the daily thermal cycle do a 375 00:17:42,320 --> 00:17:40,040 total RNA extraction and get its 376 00:17:44,360 --> 00:17:42,330 transcriptome sequence to find out which 377 00:17:46,910 --> 00:17:44,370 genes are up and down regulated under 378 00:17:49,250 --> 00:17:46,920 the free stress compared to optimal 379 00:17:52,549 --> 00:17:49,260 temperature and to see if it's active 380 00:17:54,710 --> 00:17:52,559 during the whole free soft cycle so 381 00:17:57,619 --> 00:17:54,720 all this work is relevant to the NASA 382 00:18:00,110 --> 00:17:57,629 Astrobiology roadmap because it aims to 383 00:18:01,970 --> 00:18:00,120 determine the physiological state of 384 00:18:03,619 --> 00:18:01,980 microbial cells that are found in 385 00:18:06,049 --> 00:18:03,629 extremely dry and temperature 386 00:18:08,779 --> 00:18:06,059 fluctuating environments to get more 387 00:18:10,549 --> 00:18:08,789 insight on the dynamics of survival of 388 00:18:13,220 --> 00:18:10,559 my keurig and its possibly on the 389 00:18:16,340 --> 00:18:13,230 surface of Mars and our work is the 390 00:18:19,430 --> 00:18:16,350 first to explore adaptations to external 391 00:18:21,470 --> 00:18:19,440 thermal fluctuation by analyzing the 392 00:18:22,999 --> 00:18:21,480 genome and transcriptome of what at this 393 00:18:27,080 --> 00:18:23,009 point can be called a poly external 394 00:18:31,460 --> 00:18:27,090 philic yeast so given its unique ability 395 00:18:33,799 --> 00:18:31,470 to withstand a lot of stressors it is a 396 00:18:35,690 --> 00:18:33,809 potential model organs of astrobiology 397 00:18:38,749 --> 00:18:35,700 and for stress resistance studies on 398 00:18:40,789 --> 00:18:38,759 eukaryotes so I want to thank the 399 00:18:43,310 --> 00:18:40,799 National Science Foundation's and the US 400 00:18:46,759 --> 00:18:43,320 Air Force which gave up the grants to be 401 00:18:48,820 --> 00:18:46,769 able to do this work and the Alpine and 402 00:18:51,710 --> 00:18:48,830 microbial Observatory which is my lab 403 00:18:53,629 --> 00:18:51,720 that has now become Arctic and Antarctic 404 00:18:55,700 --> 00:18:53,639 as well so if you're interested in 405 00:18:58,369 --> 00:18:55,710 looking at pretty pictures of all our 406 00:19:07,609 --> 00:18:58,379 sites and our work this is our website 407 00:19:08,149 --> 00:19:07,619 thank you thank you very much Laura we 408 00:19:16,309 --> 00:19:08,159 have time for 409 00:19:21,389 --> 00:19:19,589 right so I noticed in one of your slides 410 00:19:23,339 --> 00:19:21,399 you had something that you called plant 411 00:19:24,809 --> 00:19:23,349 material going down when you added water 412 00:19:27,239 --> 00:19:24,819 and nutrients and I was wondering if you 413 00:19:35,399 --> 00:19:27,249 could explain that a little bit oh sure 414 00:19:37,559 --> 00:19:35,409 so so when we look at this for example 415 00:19:41,989 --> 00:19:37,569 like we see that our untreated 416 00:19:46,019 --> 00:19:44,309 elevations have a lot of plant materials 417 00:19:48,779 --> 00:19:46,029 that we know it's not growing there but 418 00:19:50,399 --> 00:19:48,789 it's blown in so what we see is that 419 00:19:52,349 --> 00:19:50,409 there's a reduction of that plant 420 00:19:54,629 --> 00:19:52,359 material so we have two hypotheses about 421 00:19:56,249 --> 00:19:54,639 how that's happening so one is that 422 00:19:59,869 --> 00:19:56,259 Cryptococcus is actually taking 423 00:20:03,180 --> 00:19:59,879 advantage of that and like actually like 424 00:20:06,449 --> 00:20:03,190 degrading that plant material that is 425 00:20:08,639 --> 00:20:06,459 blown in we also saw that it has like a 426 00:20:11,459 --> 00:20:08,649 lot of genes that are able to degrade 427 00:20:14,009 --> 00:20:11,469 some plant compounds some plant derived 428 00:20:18,269 --> 00:20:14,019 compounds or the other option is that it 429 00:20:20,399 --> 00:20:18,279 will simply be degraded as a as a result 430 00:20:23,099 --> 00:20:20,409 of the free cell cycle itself because 431 00:20:25,680 --> 00:20:23,109 it's known to damage a lot of cells so 432 00:20:27,299 --> 00:20:25,690 it may be ethan alpha via the 433 00:20:29,219 --> 00:20:27,309 Cryptococcus or it may be just like 434 00:20:31,379 --> 00:20:29,229 degraded but in each case we suspect 435 00:20:33,149 --> 00:20:31,389 that it will you know make advantage of 436 00:20:36,869 --> 00:20:33,159 whatever new trend comes out of them 437 00:20:38,920 --> 00:20:36,879 okay thank you very much Lauren thank