High quality draft genome sequence of Bacteroides barnesiae type strain BL2 T (DSM 18169 T ) from chicken caecum

Classification and features

A 1301 bp long contig contained the most complete 16S rRNA gene copy in the draft
genome. This partial gene differed by 7 nucleotides (0.5 %) from the 16S rRNA reference
sequence (AB253726) generated for the original description of B. barnesiae 1]. Such a difference is not unusual when comparing original sequences from the time
organisms were initially described with sequences of type strain genomes sequenced
in the KMG project 9], a problem that was only partially resolved in the sequencing orphan species initiative
(SOS) 10]. A representative 16S rRNA gene sequence of strain BL2
^T
was compared with GenBank using NCBI BLAST. The single most frequent genus found was
Bacteroides . The highest-scoring environmental sequences (up to 99.8 % sequence identity), including
HQ784912 (‘gastrointestinal specimens clone ELU0102-T240-S-NI_000093’), were all from a study
on gastrointestinal specimens linked to inflammatory bowel diseases phenotype in human
ileum 11] and indicate that close relatives of strain BL2
^T
and representatives of B. barnesiae are also relevant to human health. Fig. 1 shows the phylogenetic position of B. barnesiae in a 16S rRNA gene sequence-based tree.

Fig. 1. Phylogenetic tree based on the 16S rRNA gene sequences showing the relationship of
Bacteroides barnesiae strain BL2
^T
among the genus Bacteroides . The tree was constructed by the neighbor-joining method. Numbers at nodes indicate
the percentage bootstrap values of 1000 replicates. Bars, 0.01 substitutions per nucleotide
position. Accession numbers are given for each strain

The cells of B. barnesiae are pleomorphic rods (0.5-1.4?×?0.8-10.6 ?m) (Fig. 2). The cells are usually arranged singly or in pairs 1]. B. barnesiae is a Gram-negative, non-sporeforming bacterium (Table 1) that is described as non-motile, with only seven genes associated with motility
having been found in the genome (see below). The optimum temperature for growth of
strain BL2
^T
is 37 °C. B. barnesiae is a strictly anaerobic chemoorganotroph and is able to ferment glucose, lactose,
sucrose, maltose, salicin, xylose, cellobiose, mannose and raffinose 1]. The organism hydrolyzes esculin but does not liquefy gelatin, and neither reduces
nitrate nor produces indole from tryptophan 1]. B. barnesiae does not utilize mannitol, arabinose, glycerol, melezitose, sorbitol, rhamnose or
trehalose 1]. Growth is possible in the presence of bile 1]. Major fermentation products from broth (1 % peptone, 1 % yeast extract, and 1 %
glucose each (w/v)) are acetic acid and succinic acid, whereas isovaleric acid is
produced in small amounts 1]. B. barnesiae shows activity for ?-galactosidase, ?-galactosidase, ?-glucosidase, ?-glucosidase,
?-arabinosidase, N-acetyl-?-glucosaminidase, ?-fucosidase, alkaline phosphatase, leucyl glycine arylamidase,
alanine arylamidase and glutamyl glutamic acid arylamidase but no activity urease,
catalase, arginine dihydrolase, ?-galactosidase 6-phosphate, ?-glucuronidase, glutamic
acid decarboxylase and arginine, proline, phenylalanine, leucine, pyroglutamic acid,
tyrosine, glycine, histidine and serine arylamidase 1].

Fig. 2. Light microscope image of strain BL2
^T

B. barnesiae strain BL2
^T
contains menaquinones MK-10 (58 %) and MK-11 (34 %) as principal respiratory quinones,
small amounts of MK-8, MK-9 and MK-12 (2 % each) are found as minor components 1]. The major fatty acids found were anteiso-C
_15:0
(32 %), iso-C
_15:0
(15 %), 3-hydroxy C
_16:0
(10 %) and C
_16:0
(10 %). Fatty acids C
_14:0
(4 %), C
_15:0
(2 %), C
_18:1?9c (4 %), C
_18:2?6,9c (2 %) and 3-hydroxy iso-C1
_7:0
(7 %) were found in minor amounts 1]. Chemotaxonomic features are in line with known features from other representatives
of the genus 1].