{"id":10724,"date":"2012-06-15T17:57:38","date_gmt":"2012-06-15T20:57:38","guid":{"rendered":"http:\/\/revistapesquisa.fapesp.br\/?p=10724"},"modified":"2017-03-01T12:57:10","modified_gmt":"2017-03-01T15:57:10","slug":"tiny-but-hefty","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/tiny-but-hefty\/","title":{"rendered":"Tiny, but hefty"},"content":{"rendered":"

\"058-060_Astrobiologia_193-1\"illustration Dr\u00fcm | INFOGRAPHICS Tiago Cirillo<\/span><\/a>They survive under conditions that are unthinkable for any other beings living on earth. Their homes are hyper saline waters, torrid deserts, volcano craters and Antarctic icebergs. These are live beings that can only be seen under a microscope, yet they are gigantic in terms of what they reveal to astrobiologists such as Claudia Lage, a professor at the Federal University of Rio de Janeiro (UFRJ). \u201cThe genetic structure of microorganisms such as viruses, bacteria and archaea is so diversified that they could have been formed in totally different places in the Universe,\u201d she says. This notion is based on panspermia, a hypothesis that proposes that life originates in multiple points in the Universe, and not necessarily and exclusively on Earth.<\/p>\n

The superhero of this world is the Deinococcus radiodurans<\/em> bacteria, which is resistant to high radiation doses. In simulations in particle accelerators, these bacteria proved to be able to resist journeys in outer space while traveling in fragments of dust (see<\/em> Pesquisa FAPESP issue 176<\/em><\/a>). Without the protection of a spaceship, the interplanetary environment is deadly for live beings: extremely high doses of ultraviolet radiation and X-rays plus pitiless bombarding by particles accelerated by solar explosions make it impossible for any form of life to exist.<\/p>\n

Claudia and biologist Ivan Paulino Lima, also from UFRJ, in partnership with researchers from the University of S\u00e3o Paulo (USP), from Italy, and from the UK, have concluded a new study showing that the Deinococcus<\/em> can survive – without any major damage – the particles given off by solar winds, of which protons are the most harmful. This resistance would allow these bacteria, riding on the dust that is disseminated throughout the Universe, to travel for millions of years through outer space. This is enough time to travel from Mars to Earth, as was explained in the conclusion of the study published in Astrobiology<\/em> at the end of 2011. This conclusion is based on experiments conducted with particle accelerators in Italy and in the UK. The experiments simulated the typical conditions of interplanetary voyages, including proton rays, carbon and electron ions in a vacuum, that would be faced by microorganisms travelling on their own or in the dust particles released by comets or asteroids. The experiment showed that the weaker energies, a characteristic of ordinary solar winds, have no effect on the Deinococcus bacteria<\/em>, even when the latter are unprotected. The solar explosions release stronger and more lethal energies, but, depending on how strong they are, all the bacteria have to do is to stick to the dust particles \u2013 even as solar explosions release increasingly stronger and deadlier energies – to protect themselves from the bombarding of the particles. \u201cThese energies do not occur frequently enough to destroy the bacteria,\u201d adds Ivan Paulino Lima, who is currently in California attending a postgraduate program at Nasa (the United States\u2019 National Space Agency).<\/p>\n

Danger in outer space<\/strong>
\nOne of the study\u2019s main findings is that outer space particles do not pose a major obstacle to these microorganisms. Therefore, cosmic dust is essential to protect the bacteria from ultraviolet radiation and rather than from bombardment by protons, to which the Deinococcus <\/em>proved to be resistant. \u201cStars are true stations of radiation,\u201d says the researcher. The study showed that at the end of an interplanetary voyage, the superbacterium would have survived long enough to land on Earth, even though it had come close to the Sun. According to the research, it could resist for more than a year \u2013 420 days \u2013 the doses of ultraviolet radiation commonly found on the Earth\u2019s orbit, even without the protection of the atmosphere. The time limit was not defined by the athletic fitness of the potential extraterrestrial travelers, but by the available period that the researchers had to conduct tests at the National Synchrotron Light Laboratory (LNLS), the particle accelerator in Campinas, S\u00e3o Paulo State. It is possible that the bacteria could survive for much longer.<\/p>\n

\"058-060_Astrobiologia_193-2\"<\/a>Another recent research project of the group, also published in Astrobiology,<\/em> expanded on the possibilities of survival in outer space and showed that this bacterium is not the only live being able to survive under the harsh conditions of the regions near stars and planets, conditions even more lethal than the bombardments in the interplanetary zone. Two other microorganism species \u2013 the Natrialba magadii<\/em> and the Haloferax volcanii<\/em> \u2013 also survived high doses of ultraviolet radiation, although this radiation was weaker than that supported by the champion among the bacteria. \u201cThey resembled the Deinococcus<\/em> in this respect,\u201d says Claudia, \u201cand this in itself is impressive, as they were subject to extremely high doses of radiation.\u201d This is the first time that this kind of organism \u2013 archaea, forms of life that for a long time had been confused with bacteria, but are actually very different from the genetic and evolutionary point of view \u2013 is put through a simulation of interplanetary conditions. Of the two, the N. magadii<\/em> was the most surprising, having proven to be even more resistant to the preparatory treatment for the experiments \u2013 which included high vacuum and dehydration – than even the Deinococcus<\/em>. This preparatory treatment was powerful enough to exterminate non-extremophile bacteria such as Escherichia coli<\/em>, extensively found in human environments. Up to a certain level of radiation, the three microorganisms exhibited a similar survival capacity. N. magadii<\/em> did better above this level; H. volcanii<\/em> did not resist, possibly because it had become more fragile as a result of the vacuum. However, this has not discouraged Claudia. \u201cEven when a significant portion of a sample is sprayed with radiation, some archaea survive the high dose of ultraviolet rays, perhaps to an extent that might enable the species to colonize other planets,\u201d says the astrobiologist from UFRJ. \u201cIn the next simulation, we will submit them to conditions that are more similar to the ones in their natural homes,\u201d she adds. Claudia justifies the importance of the test by explaining that cosmic dust can be comprised of various elements, including salts such as silicates or carbonates, which can provide several different degrees of protection.<\/p>\n

The performance of the archaea under these harsh conditions is not entirely unexpected. Indeed, many species known to be extremophiles, i.e., they thrive under harsh circumstances and populate different kinds of unpleasant environments, such as hyper saline waters and smoke-spouting volcanic craters. In Claudia\u2019s opinion, the research study results are important because they illustrate the enormous difference between bacteria and archaea. \u201cArchaea are a separate kingdom and are considered more primitive than bacteria.\u201d Thus, the findings suggest that the simplest forms of life might be able to travel and to colonize different places on the Universe.<\/p>\n

According to Claudia, the cell membrane is essential for this protection, to prevent radiation from affecting the genetic material. This membrane is similar in the three species studied by Claudia\u2019s group. This was unexpected because it is not typical in bacteria such as the Deinococcus<\/em>. In the case of the archaea, offsetting mechanisms in the membrane prevent water loss, even in hyper saline environments. The researchers believe that this protects the cells from radiation, even though the cell envelope of the N. magadii<\/em> has not been studied in detail yet. The Deinococcus<\/em> has another characteristic besides its reinforced membrane: each bacterium is comprised of four parts, as if it had begun to split, without this process being completed. As a result, the organism has additional copies of its full genome, enabling it to retrieve information if one of the parts is destroyed.<\/p>\n

Terrestrial extremes<\/strong>
\nIn their search for signs of distinct origins of life, the researchers are analyzing in detail environments in which only extremophile bacteria can survive, such as Lake Vostok, which lies deep in the Antarctic subsoil. The region was perforated by Russian scientists in February. One of the recent discoveries in extreme environments of this planet is a bacterium found in Antarctica, which is being studied by Amanda Bendia, one of Claudia\u2019s students. Amanda is going to present her master\u2019s thesis this month. When submitted to high doses of ultraviolet rays, these still nameless bacteria reacted like the Deinococcus<\/em>. The next step is to discover the identity of these newly found bacteria. If it is another species of Deinococcus<\/em>, it will prove to be the first member of a genus adapted to extremely high temperatures yet able to survive in ice. If it is a different bacterium, it will be one that is more independent and able to survive under outer space conditions. Both are exciting possibilities.<\/p>\n

In addition to exploring the possible existence of live beings circulating around the Universe (even though they differ a lot from the Martians in space ships that we see in films), research studies in this field also have practical applications: namely, finding out what is needed to kill these super powerful bacteria. \u201cBefore sending a probe to Mars, it is necessary to develop extremely powerful sterilization processes so that these extremophiles do not leave the Earth,\u201d Claudia explains.<\/p>\n

This story will probably expand going forward, when AstroLab \u2013 the laboratory located in the city of Valinhos, State of S\u00e3o Paulo \u2013 goes into full operation. This lab is to specialize in investigating possibilities of life in outer space. One of the National Science and Technology Institutes (INCTs) funded by FAPESP and by the National Council of Scientific and Technological Development (CNPq), the center has, since January, been analyzing micro communities living in harsh environments, such as icebergs and the bottom of the sea. \u201cThe great advantage is that we can conduct all the steps \u2013 from the storage of samples to outer space simulations – at one facility,\u201d says Douglas Galante, from the Institute of Astronomy, Geophysics and Atmosphere Sciences at the University of S\u00e3o Paulo (IAG-USP), and one of the coordinators of the new research center, together with Fabio Rodrigues and Rubens Duarte, both from USP. At present, the equipment that will allow outer space conditions to be simulated is stored on a ship on its way to Brazil. Galante promises to have good news very soon.<\/p>\n

Scientific articles<\/em>
\nPAULINO-LIMA, I. G. et al.<\/em> Survival of Deinococcus radiodurans<\/em> against laboratory-simulated solar wind charged particles<\/a>. Astrobiology<\/strong>. v. 11, n. 9, p. 875-82. nov. 2011.
\nABREVAYA, X. C. et al<\/em>. Comparative survival analysis of Deinococcus radiodurans<\/em> and the haloarchaea Natrialba magadii<\/em> and Haloferax volcanii<\/em>, exposed to vacuum ultraviolet radiation<\/a>. Astrobiology<\/strong>. v. 11, n. 10, p. 1.034-40. dec. 2011.<\/p>\n","protected":false},"excerpt":{"rendered":"Microorganisms invisible to the naked eye can survive interplanetary trips","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[159],"tags":[205,209,235],"coauthors":[95],"class_list":["post-10724","post","type-post","status-publish","format-standard","hentry","category-science","tag-astronomy","tag-biology","tag-physics"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/10724","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=10724"}],"version-history":[{"count":0,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/10724\/revisions"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=10724"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=10724"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=10724"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=10724"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}