{"id":8364,"date":"2016-04-08T11:14:14","date_gmt":"2016-04-08T11:14:14","guid":{"rendered":"http:\/\/revoscience.com\/en\/?p=8364"},"modified":"2016-04-08T11:14:14","modified_gmt":"2016-04-08T11:14:14","slug":"iron-working-like-oxygen-in-microbes","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/iron-working-like-oxygen-in-microbes\/","title":{"rendered":"Iron working like oxygen in microbes"},"content":{"rendered":"
\"The<\/a>
The steamy volcanic vent at Chocolate Pot hot spring in Yellowstone National Park, an iron-rich but relatively cool hot spring where a variety of fascinating microorganisms thrive without oxygen. COURTESY OF NATHANIEL FORTNEY<\/figcaption><\/figure>\n

A pair of papers from a UW\u2013Madison geoscience lab shed light on a curious group of bacteria that use iron in much the same way that animals use oxygen: to soak up electrons during biochemical reactions. When organisms \u2014 whether bacteria or animal \u2014 oxidize carbohydrates, electrons must go somewhere.<\/span><\/p>\n

The studies can shed some light on the perennial question of how life arose, but they also have slightly more practical applications in the search for life in space, says senior author\u00a0Eric Roden<\/span><\/a>, a professor of geoscience at UW\u2013Madison.<\/span><\/p>\n

\"Eric<\/a>
Eric Roden<\/figcaption><\/figure>\n

Animals use oxygen and \u201creduce\u201d it to produce water, but some bacteria use iron that is deficient in electrons, reducing it to a more electron-rich form of the element. Ironically, electron-rich forms of iron can also supply electrons in the opposite \u201coxidation\u201d reaction, in which the bacteria literally \u201ceat\u201d the iron to get energy.<\/span><\/p>\n

Iron is the fourth-most abundant element on the planet, and because free oxygen is scarce underwater and underground, bacteria have \u201cthought up,\u201d or evolved, a different solution: moving electrons to iron while metabolizing organic matter.<\/span><\/p>\n

These bacteria \u201ceat organic matter like we do,\u201d says Roden. \u201cWe pass electrons from organic matter to oxygen. Some of these bacteria use iron oxide as their electron acceptor. On the flip side, some other microbes receive electrons donated by other iron compounds. In both cases, the electron transfer is essential to their energy cycles.\u201d<\/span><\/p>\n

Whether the reaction is oxidation or reduction, the ability to move an electron is essential for the bacteria to process energy to power its lifestyle.<\/span><\/p>\n

Roden has spent decades studying iron-metabolizing bacteria. \u201cI focus on the activities and chemical processing of microorganisms in natural systems,\u201d he says. \u201cWe collect material from the environment, bring it back to the lab, and study the metabolism through a series of geochemical and microbiological measurements.\u201d<\/span><\/p>\n

[pullquote]Roden and doctoral student\u00a0<\/span>Nathan Fortney<\/span><\/a>\u00a0and research scientist\u00a0<\/span>Shaomei He<\/span><\/a>\u00a0explored how the cultured organisms changed the oxidation state \u2014 the number of electrons \u2014 in the iron compounds.<\/span>[\/pullquote]<\/p>\n

The current studies focus on bacteria samples from Chocolate Pot hot spring, a relatively cool geothermal spring in Yellowstone National Park that is named for the dark, reddish-brown color of ferric oxide. Related studies deal with a culture obtained from a much less auspicious environment \u2014 a ditch in Germany. Both studies are online, in\u00a0Applied and Environmental Microbiology<\/span><\/a>\u00a0and in\u00a0Geobiology<\/span><\/a>.<\/span><\/p>\n

During the studies, Roden and doctoral student\u00a0Nathan Fortney<\/span><\/a>\u00a0and research scientist\u00a0Shaomei He<\/span><\/a>\u00a0explored how the cultured organisms changed the oxidation state \u2014 the number of electrons \u2014 in the iron compounds. They also used an advanced genome-sequencing instrument at the UW\u2013MadisonBiotechnology Center<\/span><\/a>\u00a0to identify strings of DNA in the genomes.<\/span><\/p>\n

\u201cMore than 99 percent of microbial diversity cannot be obtained in pure culture,\u201d says He, meaning they cannot be grown as a single strain for analysis. \u201cInstead of going through the long, laborious and often unsuccessful process of isolating strains, we apply genomic tools to understand how the organisms were doing what they were doing in mixed communities.\u201d<\/span><\/p>\n

The researchers found some unknown bacteria capable of iron metabolism, and also got genetic data on a unique capacity that some of them have: the ability to transport electrons in both directions across the cell\u2019s outer membrane. \u201cBacteria have not only evolved a metabolism that opens niches to use iron as an energy,\u201d says He, \u201cbut these new electron transport mechanisms give them a way to use forms of iron that can\u2019t be brought inside the cell.\u201d<\/span><\/p>\n

\"An<\/a>
An abstract representation of the microbial community in a bacterial culture obtained from Chocolate Pot hot spring. The colored dots represent DNA fragments from each microbial variety; the fragments are clustered based on unique similarities within an organism\u2019s DNA. COURTESY OF NATHANIEL FORTNEY<\/figcaption><\/figure>\n

\u201cThese are fundamental studies, but these chemical transformations are at the heart of all kinds of environmental systems, related to soil, sediment, groundwater and waste water,\u201d says Roden. \u201cFor example, the Department of Energy is interested in finding a way to derive energy from organic matter through the activity of iron-metabolizing bacteria.\u201d These bacteria are also critical to the life-giving process of weathering rocks into soil.<\/span><\/p>\n

Iron-metabolizing bacteria have been known for a century, Roden says, and were actually discovered in Madison-area groundwater. \u201cGeologists saw organisms that formed these unique structures that were visible under the light microscope. They formed stalks or sheaths, and it turned out they were used to move iron.\u201d<\/span><\/p>\n

Roden and He are geobiologists, interested in how microbes affect geology, but the significance of microbes in Earth\u2019s evolution is only now being fully appreciated, Roden says. \u201cEyebrows rose when we contacted the Biotech Center three or four year ago to discuss sequencing: \u2018Who are these people from geology, and what are they talking about?\u2019 But we stuck with it, and it\u2019s turned into a pretty cool collaboration that has allowed us to apply their excellent tools that are more typically applied to biomedical and related microbial issues.\u201d<\/span><\/p>\n

Some of the iron-metabolizing bacteria appear quite early on the tree of life, making the studies relevant to discovering the origins of life, but the findings also have implications in the search for life in space, Roden says. \u201cOur support comes from NASA\u2019s astrobiology institute at UW\u2013Madison. It\u2019s possible that on a rocky planet like Mars, life could rely on iron metabolism instead of oxygen.<\/span><\/p>\n

\u201cA fundamental approach in astrobiology is to use terrestrial sites as analogs, where we look for insight into the possibilities on other worlds,\u201d Roden continues. \u201cSome people believe that use of iron oxide as an electron acceptor could have been the first, or one of the first, forms of respiration on Earth. And there\u2019s so much iron around on the rocky planets.\u201d<\/span><\/p>\n

\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

A pair of papers from a UW\u2013Madison geoscience lab shed light on a curious group of bacteria that use iron in much the same way that animals use oxygen: to soak up electrons during biochemical reactions.<\/p>\n","protected":false},"author":6,"featured_media":8365,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,17],"tags":[],"class_list":["post-8364","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-biology","category-research"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517-150x150.jpeg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517-300x200.jpeg",300,200,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",95,63,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",448,299,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",96,64,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2016\/04\/CP_vent_fullview-775x517.jpeg",150,100,false]},"author_info":{"info":["Amrita Tuladhar"]},"category_info":"Biology<\/a> Research<\/a>","tag_info":"Research","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/8364","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=8364"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/8364\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/8365"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=8364"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=8364"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=8364"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}