Expansion of ability of denitrification within the filamentous colorless sulfur bacteria of the genus Thiothrix. Issue 1 (21st August 2014)

• Record Type: Journal Article
• Authors: Trubitsyn, Ivan V.; Belousova, Elena V.; Tutukina, Maria N.; Merkel, Alexander Y.; Dubinina, Galina A.; Grabovich, Margarita Y.
• Is Part Of: FEMS microbiology letters. Volume 358:Issue 1(2014:Sep.)
• Page Start: 72
• Page End: 80
• Publication Date: 2014-08-21
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1111/1574-6968.12548
• Languages: English
• ISSNs: 0378-1097

Abstract

<abstract abstract-type="main" id="fml12548-abs-0001"> <title>Abstract</title> <p>Filamentous sulfur bacteria of the genus <italic>Thiothrix</italic> are able to respire nitrate (<inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgh177f2zcj" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:03781097:media:fml12548:fml12548-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mtext>NO</mml:mtext><mml:mn>3</mml:mn><mml:mo>−</mml:mo></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:msubsup><mml:mtext>NO</mml:mtext><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula>) under anaerobic growth. Here, <italic>Thiothrix caldifontis</italic> (G1<sup>T</sup>, G3), <italic>Thiothrix unzii</italic> (A1<sup>T</sup>, TN) and <italic>Thiothrix lacustris </italic>AS were shown to be capable of further reduction of nitrite and/or nitrous oxides (denitrification). In particular, in the genomes of these strains, excluding <italic>T. unzii </italic>TN, the <italic>nirS</italic> gene encoding periplasmic respiratory nitrite reductase was detected, and for <italic>T. lacustris </italic>AS the <italic>nirS</italic> expression was confirmed during anaerobic growth. The <italic>nirK</italic> gene, coding for an alternative nitrite reductase, and the <italic>nrfA</italic> gene, encoding nitrite reduction to ammonia, were not found in any investigated strains. All <italic>Thiothrix</italic> species capable of denitrification possess the <italic>cnorB</italic> gene encoding cytochrome c‐dependent NO reductase but not the <italic>qnorB</italic> gene coding for quinol‐dependent NO reductase. Denitrifying capacity ('full' or 'truncated') can vary between strains belonging to the same species and correlates with physical‐chemical parameters of the environment such as nitrate, hydrogen sulfide and oxygen concentrations. Phylogenetic analysis revealed the absence of recent horizontal transfer events for <italic>narG</italic> and <italic>nirS</italic>; however, <italic>cnorB</italic> was subjected to gene transfer before the separation of modern species from a last common ancestor of the <italic>Thiothrix</italic> species.</p> </abstract>