Skip to main content

Hopanoid lipids in Frankia: identification of squalene-hopene cyclase gene sequences

Buy Article:

$50.00 plus tax (Refund Policy)

Abstract:

In Frankia, the microsymbiont in actinorhizal root nodules, nitrogen fixation takes place in specialized structures called vesicles. The lipidic vesicle envelope forms a barrier to oxygen diffusion, an essential part of the nitrogenase oxygen protection system. We have shown previously that the vesicle envelope is composed primarily of two species of hopanoid lipids, sterol-like molecules that are synthesized in a wide range of bacteria, including Frankia, several cyanobacteria, and rhizobia. The levels of hopanoid found in Frankia are among the highest of any organism known to date. Here we report that short (328-bp) DNA sequences from several strains of Frankia spp. have been identified that are homologous to a portion of the coding region of squalene-hopene cyclase (shc) genes. The fragments and corresponding polymerase chain reaction (PCR) primers can be used in phylogenetic comparisons of Frankia, both within Frankiaceae and among bacteria that synthesize hopanoids.Key words: Frankia, squalene-hopene cyclase, shc, hopanoid, phylogeny, actinorhizal.

Chez Frankia, le microsymbiont des nodules de racines actinorhiziennes, la fixation de l'azote prend place au niveau de structures spécialisées appelées vésicules. L'enveloppe lipidique des vésicules forme une barrière à la diffusion de l'oxygène, ce qui constitue la composante essentielle du système de protection nitrogénase-oxygène. Nous avons démontré par le passé que l'enveloppe des vésicules est composée principalement de deux espèces de lipides hopanoïdes, des molécules apparentées au stérols qui sont synthétisées par un éventail de bactéries, incluant Frankia, plusieurs types de cyanobactéries et des rhizobiums. Les niveaux d'hopanoïdes retrouvés chez Frankia sont parmi les plus élevés de tous les organismes connus à ce jour. Ici, nous rapportons que de courtes (328 pb) séquences d'ADN de plusieurs souches du groupe de Frankia homologues à une portion de la région codante des gènes de la cyclase squalène-hopène (shc) ont été identifiées. Ces fragments et les amorces de PCR correspondantes peuvent être utilisées pour les comparaisons phylogénétiques de Frankia, tant au niveau des Frankiaceae que parmi les bactéries qui synthétisent les hopanoïdes.Mots clés : Frankia, cyclase squalène-hopène, shc, hopanoïde, phylogénie, actinorhizienne.[Traduit par la Rédaction]

Keywords: Frankia; actinorhizal; actinorhizienne; cyclase squalène-hopène; hopanoid; hopanoïde; phylogeny; phylogénie; shc; squalene-hopene cyclase

Document Type: Research Article

Publication date: June 1, 2001

More about this publication?
  • Published since 1954, this monthly journal contains new research in the field of microbiology including applied microbiology and biotechnology; microbial structure and function; fungi and other eucaryotic protists; infection and immunity; microbial ecology; physiology, metabolism and enzymology; and virology, genetics, and molecular biology. It also publishes review articles and notes on an occasional basis, contributed by recognized scientists worldwide.
  • Information for Authors
  • Submit a Paper
  • Subscribe to this Title
  • Terms & Conditions
  • Sample Issue
  • Reprints & Permissions
  • Ingenta Connect is not responsible for the content or availability of external websites
nrc/cjm/2001/00000047/00000006/art00009
dcterms_title,dcterms_description,pub_keyword
6
5
20
40
5

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more