Algoriphagus machipongonensis sp. nov., co-isolated with a colonial choanoflagellate

Abstract

A Gram-negative, non-motile, non-spore-forming bacterial strain, PR1(T), was isolated from a mud core sample containing colonial choanoflagellates near Hog Island, Virginia, USA. Strain PR1(T) grew optimally at 30 °C and with 3 % (w/v) NaCl. Strain PR1(T) contained MK-7 as the major menaquinone as well as carotenoids but lacked pigments of the flexirubin-type. The predominant fatty acids were iso-C(15 : 0) (29.4 %), iso-C(17 : 1)ω9c (18.5 %) and summed feature 3 (C(16 : 1)ω6c and/or C(16 : 1)ω7c; 11.3 %). The major polar lipids detected in strain PR1(T) were phosphatidylethanolamine, an unknown phospholipid, an aminophospholipid, an aminolipid and two lipids of unknown character. The DNA G+C content was 38.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain PR1(T) fell within the cluster comprising the genus Algoriphagus and was most closely related to Algoriphagus halophilus JC 2051(T) (95.4 % sequence similarity) and Algoriphagus lutimaris S1-3(T) (95.3 % sequence similarity). The 16S rRNA gene sequence similarity between strain PR1(T) and the type strains of other species of the genus Algoriphagus were in the range 91-95 %. Differential phenotypic properties and phylogenetic and genetic distinctiveness of strain PR1(T) demonstrated that this strain was distinct from other members of the genus Algoriphagus, including its closest relative, A. halophilus. Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strain PR1(T) should be placed in the genus Algoriphagus as a representative of a novel species, for which the name Algoriphagus machipongonensis sp. nov. is proposed. The type strain is PR1(T) (= ATCC BAA-2233(T) = DSM 24695(T)).

Fig. 1.

Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showing the position of strain PR1^T relative to members of the genus Algoriphagus and the family Cyclobacteriaceae. Bootstrap values (>70 %) based on 1000 replicates are shown at branch nodes. Filled circles indicate that the corresponding nodes were also recovered in maximum-likelihood and maximum-parsimony analyses. Open circles indicate that the corresponding nodes were also recovered in either the maximum-likelihood or maximum-parsimony analyses. Cytophaga hutchinsonii ATCC 33406^T (accession no. M58768) was used as an outgroup (not shown). Bar, 0.01 substitutions per nucleotide position.