<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Juan* Liu</style></author><author><style face="normal" font="default" size="100%">Pearce, Carolyn I</style></author><author><style face="normal" font="default" size="100%">Shi, Liang</style></author><author><style face="normal" font="default" size="100%">Wang, Zheming</style></author><author><style face="normal" font="default" size="100%">Shi, Zhi</style></author><author><style face="normal" font="default" size="100%">Arenholz, Elke</style></author><author><style face="normal" font="default" size="100%">Rosso, Kevin M*</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Particle size effect and the mechanism of hematite reduction by the outer membrane cytochrome OmcA of Shewanella oneidensis MR-1</style></title><secondary-title><style face="normal" font="default" size="100%">Geochimica et Cosmochimica Acta</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2016</style></year></dates><publisher><style face="normal" font="default" size="100%">Pergamon</style></publisher><volume><style face="normal" font="default" size="100%">193</style></volume><pages><style face="normal" font="default" size="100%">160-175</style></pages><isbn><style face="normal" font="default" size="100%">0016-7037</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span&gt;&lt;span&gt;The cycling of iron at the Earth’s near surface is profoundly influenced by dissimilatory metal reducing microorganisms, and many studies have focused on unraveling&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/electron-transfer&quot; title=&quot;Learn more about electron transfer&quot;&gt;electron transfer&lt;/a&gt;&amp;nbsp;mechanisms between these bacteria and Fe(III)-(oxyhydr)oxides. However, these efforts have been complicated by the fact that these minerals often occur in the micro- to nanosize regime, and in relevant natural environments as well as in the laboratory are subject to aggregation. The nature of the physical interface between the cellular envelope, the outer-membrane&amp;nbsp;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/cytochromes&quot; title=&quot;Learn more about cytochromes&quot;&gt;cytochromes&lt;/a&gt;responsible for facilitating the interfacial electron transfer step, and these complex mineral particulates is thus difficult to probe. Previous studies using whole cells have reported reduction rates that do not correlate with particle size. In the present study we isolate the interaction between the decaheme outer-membrane cytochrome OmcA of&amp;nbsp;&lt;/span&gt;&lt;em&gt;Shewanella oneidensis&lt;/em&gt;&lt;span&gt;&lt;span&gt;and nanoparticulate&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hematite&quot; title=&quot;Learn more about hematite&quot;&gt;hematite&lt;/a&gt;&lt;span&gt;, examining the reduction rate as a function of particle size and&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/reaction-products&quot; title=&quot;Learn more about reaction products&quot;&gt;reaction products&lt;/a&gt;&amp;nbsp;through detailed characterization of the electron balance and the structure and valence of iron at particle surfaces. By comparison with abiotic reduction via the smaller molecule&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/ascorbic-acid&quot; title=&quot;Learn more about ascorbic acid&quot;&gt;ascorbic acid&lt;/a&gt;&lt;span&gt;&lt;span&gt;, we show that the reduction rate is systematically controlled by the sterically accessible interfacial contact area between OmcA and hematite in particle aggregates; rates increase once&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/porosity&quot; title=&quot;Learn more about porosity&quot;&gt;pore&lt;/a&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;throat sizes in aggregates become as large as OmcA. Simultaneous measure of OmcA oxidation against Fe(II) release shows a ratio of 1:10, consistent with a cascade OmcA oxidation mechanism heme by heme.&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/x-ray&quot; title=&quot;Learn more about X ray&quot;&gt;X-ray&lt;/a&gt;&lt;span&gt;&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/absorption-spectroscopy&quot; title=&quot;Learn more about absorption spectroscopy&quot;&gt;absorption spectroscopies&lt;/a&gt;&amp;nbsp;reveal incipient&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/magnetite&quot; title=&quot;Learn more about magnetite&quot;&gt;magnetite&lt;/a&gt;&amp;nbsp;on the reacted surfaces of the hematite&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/nanoparticles&quot; title=&quot;Learn more about Nanoparticles&quot;&gt;nanoparticles&lt;/a&gt;&lt;span&gt;&amp;nbsp;after reaction. The collective findings establish the importance of accessibility of physical contact between the terminal reductases and&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/iron-oxides&quot; title=&quot;Learn more about iron oxides&quot;&gt;iron oxide&lt;/a&gt;&amp;nbsp;surfaces, and through apparent consistency of observations help reconcile behavior reported at the larger more complex scale of whole cell studies.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;</style></abstract></record></records></xml>