Hoeflea anabaenae sp. nov., an epiphytic symbiont that attaches to the heterocysts of a strain of Anabaena.

• The heterotrophic, epiphytic symbiotic bacterial strain WH2K(T) was previously isolated from a two-member culture in which it was attached to the heterocysts of a strain of Anabaena (SSM-00). Analysis of its 16S rRNA genes demonstrated that the symbiont was most closely related to the type strain of Hoeflea marina (96.9% similarity), which belongs to the family Phyllobacteriaceae within the order Rhizobiales of the class Alphaproteobacteria. A polyphasic taxonomic study was performed on strain WH2K(T) that consisted of irregular rods (2-5μm long, 0.2μm wide) that appeared to be narrower at one polar end. Optimal growth was obtained in complex media with 15 g l(-1) sea salts, at 18-34 °C (30 °C optimum) and at pH values in the range of 6.0-8.0 (6.5 optimum). Unknown growth requirements were provided by small amounts of yeast extract but not standard vitamin and trace metal solutions. Of the substrates tested, WH2K(T) was only able to utilize acetate, pyruvate, malate, and fumarate. Growth was only observed under aerobic and microaerobic conditions and nitrate was not reduced. No photosynthetic pigments were detected under any of the growth conditions tested. The predominant fatty acids were present in a summed feature that comprises C (18:1) ω7c, / 9t /12t or any combination of these (64.0%) and an unidentified fatty acid of estimated chain length (ECL of C(17.6) (13.5%), The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphoglycolipid, unknown lipids and an unidentified aminolipid. The only respiratory ubiquinone detected was Q-10. The DNA %G+C content of the strain is 58.1%. The organism can form a site-specific attached symbiotic relationship with a species of Anabaena. Based on phylogenetic and phenotypic evidence it is proposed that strain WH2K(T) be classified as a fourth species of the genus Hoeflea, for which the name Hoeflea anabaenae sp. nov. is proposed. The type strain of Hoeflea anabaenae sp. nov. is WH2K(T) (=CCUG 56626(T) =NRRL B-59520(T)).

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Mikrobiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Microbiology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

Hoeflea anabaenae

Alphaproteobacteria

Anabaena sp.

16S rRNA

cell fatty acids

polar lipids

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