L. byssophila 4M15
T is very isolated in the tree of life, with no other species allocated to the same genus and with the type strains of the members of the genus
Emticicia [
5,
6] sharing the highest degree of 16S rRNA sequence identity (88.3-88.9%) [
7], followed by
Sporocytophaga myxococcoides (85.2%) [
8] and
Siphonobacter aquaeclarae (85.0%) [
9]. No other cultured strain belonging to the species or genus has been described. Only one 16S rRNA sequence from a moderately related (95% sequence identity) uncultivated clone, W4S69 (GU560170), identified by Xu and colleagues in pharmaceutical wastewater biofilms, was reported in GenBank. Neither environmental screenings nor genomic surveys produced any sequence that could be linked to the species
L. byssophila or the genus
Leadbetterella, indicating that members of the species are not heavily represented in the so far screened habitats (status November 2010).
A representative genomic 16S rRNA sequence of
L. byssophila 4M15
T was compared using NCBI BLAST under default settings (e.g., considering only the high-scoring segment pairs (HSPs) from the best 250 hits) with the most recent release of the Greengenes database [
10] and the relative frequencies, weighted by BLAST scores, of taxa and keywords (reduced to their stem [
11]) were determined. The five most frequent genera were
Pedobacter (35.1%),
Flectobacillus (11.4%),
Leadbetterella (9.4%),
Algoriphagus (8.6%) and
Arcicella (6.8%) (80 hits in total). Regarding the single hit to sequences from members of the species, the average identity within HSPs was 100.0%, whereas the average coverage by HSPs was 97.9%. Among all other species, the one yielding the highest score was '
Kaistomonas ginsengisoli', which corresponded to an identity of 92.2% and a HSP coverage of 49.8%. The name '
Kaistomonas ginsengisoli' (strain Gsoil 085, AB245370) is also to be found in a number of publications [
12-
14], but that has since become the type strain of
Emticicia ginsengisoli [
6].
The highest-scoring environmental sequence was HM238135 ('structure full-scale air pig facility biofilter treating waste gas clone FF 92'), which showed an identity of 93.1% and a HSP coverage of 96.0%. The five most frequent keywords within the labels of environmental samples which yielded hits were 'lake' (4.8%), 'litholog/stream' (4.5%), 'biofilm' (3.3%), 'microbi' (2.9%) and 'site' (2.5%) (170 hits in total). The five most frequent keywords within the labels of environmental samples which yielded hits of a higher score than the highest scoring species were 'soil' (5.1%), 'biofilm/oxid' (5.1%), 'air, biofilt, facil, full-scal, pig, structur, treat, wast' (2.7%), 'forest, ghat, ground, india, mangrov, nich, prokaryt, select, studi, swab, western' (2.7%) and 'cold, spring' (2.6%) (5 hits in total).
shows the phylogenetic neighborhood of L. byssophila 4M15T in a 16S rRNA based tree. The sequences of the three 16S rRNA gene copies in the genome do not differ from each other, and do not differ from the previously published 16S rRNA sequence (AY854022).
Cells of
L. byssophila stain Gram-negative and are non-motile, rod shaped with a width of 0.6-0.9 µm and a length of 2-7 µm ( and ). Colonies are circular, 1-2 mm in diameter, smooth, light orange, shiny and convex with entire margin when grown on trypticase soy agar. After prolonged incubation colonies become dark orange. Strain 4M15
T grows under aerobic conditions at temperatures of 15-45°C and at a pH range of 6.0-8.0. The strain grows in the presence of 1% (w/v) NaCl, but not at 3% NaCl [
1]. Growth on carbohydrates (API 20NE) was observed for glucose, arabinose, mannose, N-acetylglucosamine and maltose but not for mannitol. Strain 4M15
T was positive for indole production and β-galactosidase, and negative for nitrate reduction and arginine dihydrolase (API 20NE). Enzymatic activity was detected for alkaline phosphatase, leucine arylamidase, valine arylamidase, trypsin, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidase, N-acetyl-β-glucosaminidase and α-fucosidase; weak enzymatic activity was observed for α-galactosidase and β-galactosidase (API ZYM).
L. byssophila produces catalase and urease [
1]. Whereas starch, gelatin, aesculin and tyrosine are hydrolyzed; agar, casein, cellulose and chitin are not. Strain 4M15
T is sensitive to ampicillin, carbencillin, lincomycin, streptomycin and tetracycline and shows resistance to benzylpenicillin, gentamicin, neomycin, oleandomycin and polymyxin B.
| Table 1Classification and general features of L. byssophila according to the MIGS recommendations [22]. |
Chemotaxonomy
The fatty acids of strain 4M15
T comprise a complex mixture of straight chain saturated and unsaturated acids, together with iso-branched, anteiso-branched and hydroxylated acids. The fatty acids comprise iso-C
15:0 (24.2%), C
16:1ω5c (2.8%), C
16:0 (5.6%), iso-C
15:0 3-OH (2.8%), iso-C
17:1ω9c (1.4%), C
16:0 3-OH (2.5%), iso-C
17:0 3-OH (10.5%) and the summed feature listed in the MIDI Sherlock system as C
16:1 ω7c and/or iso-C
15:0 2-OH (30.5%) and iso-C
15:0 2-OH and/or C
16:1 ω7c (15.9%). These two peaks probably represent C
16:1 ω7c (30.5%) and iso-C
15:0 2-OH (15.9%) of the fatty acids. The presence of saturated, unsaturated straight chain fatty acids, together with branched chain (largely iso-) normal and 2-OH and 3-OH derivatives is fairly typical of the aerobic members of the
Bacteroidetes. The major isoprenoid quinone is menaquinone MK-7, a trace amount of menaquinone MK-8 was detected [
1]. The polar lipids of
L. byssophila have not been determined, but for a number of other taxa, including
Rudanella lutea 5715S-11
T,
S. linguale DSM 74
T,
Larkinella insperata LMG 22510
T and some members of the genus
Sphingobacterium and
Parapedobacter [
29,
30] the presence of phosphatidylethanolamine as the major (diglyceride based) phospholipid and a number of not further characterized lipids and amino lipids provide useful taxonomic and evolutionary markers [
31].