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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>S.J. Rowland</dc:contributor>
  <dc:contributor>D.A. Yon</dc:contributor>
  <dc:contributor>J.R. Maxwell</dc:contributor>
  <dc:creator>J.B. Risatti</dc:creator>
  <dc:date>1984</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Abundant volatile lipids of&amp;nbsp;&lt;/span&gt;&lt;i&gt;Methanobacterium thermoautotrophicum&lt;/i&gt;&lt;span&gt;&amp;nbsp;and&amp;nbsp;&lt;/span&gt;&lt;i&gt;Methanosarcina barkeri&lt;/i&gt;&lt;span&gt;&amp;nbsp;include isoprenoid hydrocarbons (≤ C&lt;/span&gt;&lt;sub&gt;30&lt;/sub&gt;&lt;span&gt;), and C&lt;/span&gt;&lt;sub&gt;15&lt;/sub&gt;&lt;span&gt;, C&lt;/span&gt;&lt;sub&gt;20&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and C&lt;/span&gt;&lt;sub&gt;25&lt;/sub&gt;&lt;span&gt;&amp;nbsp;isoprenoid alcohols.&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. barkeri&lt;/i&gt;&lt;span&gt;&amp;nbsp;contains 2,6,10,15,19-pentamethyleicosane, whose relative stereochemistry is the same as found in marine sediments, indicating that it is a marker of methanogenic activity. The C&lt;/span&gt;&lt;sub&gt;20&lt;/sub&gt;&lt;span&gt;, C&lt;/span&gt;&lt;sub&gt;30&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and C&lt;/span&gt;&lt;sub&gt;25&lt;/sub&gt;&lt;span&gt;&amp;nbsp;alkenes in&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. thermoautotrophicum&lt;/i&gt;&lt;span&gt;&amp;nbsp;also have a preferred sterochemistry; the latter have the 2,6,10,14,18-pentamethyleicosanyl skeleton, suggesting that the alkane in marine sediments may derive from methanogens. The stereochemistry of squalane in a marine sediment is also compatible with an origin in methanogens; in contrast, the stereochemistry of pristane in&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. thermoautotrophicum&lt;/i&gt;&lt;span&gt;&amp;nbsp;indicates a fossil fuel contaminant origin, suggesting that this and certain other alkanes reported in archaebacteria might also be of contaminant origin. There is, therefore, little evidence at present that the pristane in immature marine sediments originates in methanogens. The C&lt;/span&gt;&lt;sub&gt;15&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and C&lt;/span&gt;&lt;sub&gt;20&lt;/sub&gt;&lt;span&gt;&amp;nbsp;saturated alcohols in&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. thermoautotrophicum&lt;/i&gt;&lt;span&gt;&amp;nbsp;have mainly the all-R configuration. If this is generally true for methanogens, the C&lt;/span&gt;&lt;sub&gt;20&lt;/sub&gt;&lt;span&gt;&amp;nbsp;alcohol in the Messel shale may originate mainly from methanogens, whereas that in the Green River shale may originate mainly from photosynthetic organisms.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0146-6380(84)90030-5</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Stereochemical studies of acyclic isoprenoids—XII. Lipids of methanogenic bacteria and possible contributions to sediments</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>