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Linkage of the Nitrilase-Encoding Nit1C Gene Cluster to Cyanotrophy in Acinetobacter haemolyticus

The Nit1C cluster is a conserved gene cluster of seven genes that confers bacterial growth on cyanide as the sole nitrogen source. Bacteria with this ability are referred to as cyanotrophs. To date, the linkage between Nit1C and cyanotrophy has only been demonstrated for environmental isolates but the cluster also exists in certain medically related bacteria. In this study, a nosocomial isolate, Acinetobacter haemolyticus ATCC 19194, carrying Nit1C also displayed the ability to grow on cyanide. Growth on cyanide was accompanied by the induction of the cluster as was the mere exposure of cells to cyanide. Expression of the cluster was determined by measuring the activity of the nitrilase (NitC) coded for by the cluster and by transcriptional analysis (qRT-PCR). However, a disconnect between nitC message and NitC protein was observed depending on the phase of the growth cycle, the disconnect being related to proteolytic digestion of the NitC protein. Ironically, the cluster was also discovered to be upregulated in the absence of cyanide under nitrogen starvation conditions paralleling biofilm formation. The basis of the genetic linkage to cyanotrophy is not understood but taken together with results showing that nitrogen starvation and biofilm formation are also physiologically associated with Nit1C expression, points to a critical role for the cluster in stress-induced adaptation.

Identiferoai:union.ndltd.org:unt.edu/info:ark/67531/metadc2179282
Date07 1900
CreatorsDale, Layla Momo
ContributorsKunz, Daniel A., Henard, Calvin, Hughes, Lee
PublisherUniversity of North Texas
Source SetsUniversity of North Texas
LanguageEnglish
Detected LanguageEnglish
TypeThesis or Dissertation
FormatText
RightsPublic, Dale, Layla Momo, Copyright, Copyright is held by the author, unless otherwise noted. All rights Reserved.

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