Microorganisms have evolved a spectacular diversity of metabolisms, some of which allow them to overcome environmental constraints, utilize abundant but inaccessible resources and drive nutrient cycling in various ecosystems. The termite hindgut microbial community is optimized to metabolize wood, and in recent years, the in situ physiological and ecological functions of community members have been researched. Spirochetes are abundant in the termite gut, and herein, putative aromatic meta-cleavage pathway genes typical of aerobic pseudomonads were located in genomes of homoacetogenic termite hindgut ‘anaerobes’, Treponema primitia str. ZAS-1 and ZAS-2. Phylogenetic analyses suggest the T. primitia catechol 2,3-dioxygenase and several other essential meta-pathway genes were acquired from an α-proteobacterium in the distant past to augment several genes T. primitia acquired from anaerobic firmicutes that do not directly catabolize aromatics but can contribute to the final pathway steps. Further, transcripts for each meta-pathway gene were expressed in strictly anaerobic cultures of T. primitia str. ZAS-2 indicative of constitutive pathway expression. Also, the addition of catechol + O2 to T. primitia liquid cultures resulted in the transient accumulation of trace amounts of the yellow ring cleavage product, hydroxymuconic semialdehyde. This is the first evidence of aromatic ring cleavage in the phylum (division) Spirochetes. Results also support a possible role for T. primitia in termite hindgut O2/lignin aromatic monomer metabolism. Potential O2-dependent yet nonrespiratory microbial metabolisms have heretofore been overlooked and warrant further investigation. These metabolisms could describe the degradation of plant-derived and other aromatics in microoxic environments and contribute significantly to carbon turnover.
2-hydroxymuconic semialdehyde hydrolase ARB output.nex
2-oxopent-4-enoate hydratase ARB output.nex
4-hydroxy-2-oxopentanoate aldolase ARB output.nex
4-hydroxy-2-oxopentanoate aldolase DmpG-like domain ARB output.nex
4-hydroxy-2-oxopentanoate aldolase HMGL-like domain ARB output.nex
acetaldehyde dehydrogenase ARB output.nex
acetaldehyde dehydrogenase dimerisation domain ARB output.nex
acetaldehyde dehydrogenase NAD binding domain ARB output.nex
catechol 2,3-dioxygenase ARB output.nex
catechol 2,3-dioxygenase C-terminal domain ARB output.nex
catechol 2,3-dioxygenase C-terminal domain with extra-domain region ARB output.nex
catechol 2,3-dioxygenase C-terminal domain with intra-domain region ARB output.nex
catechol 2,3-dioxygenase N-terminal domain ARB output.nex
catechol 2,3-dioxygenase N-terminal domain with extra-domain region ARB output.nex
catechol 2,3-dioxygenase N-terminal domain with intra-domain region ARB output.nex
ferredoxin-like peptide ARB output.nex
acetaldehyde dehydrogenase dimerisation domain Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase C-terminal domain with extra-domain region Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase C-terminal domain Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase C-terminal
domain with intra-domain region Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase C-terminal domain with intra-domain region.nex.con.tre
acetaldehyde dehydrogenase NAD binding domain Mr Bayes output.nex.con.tre
4-hydroxy-2-oxopentanoate aldolase Mr Bayes output.nex.con.tre
4-hydroxy-2-oxopentanoate aldolase HMGL-like domain Mr Bayes output.nex.con.tre
4-hydroxy-2-oxopentanoate aldolase DmpG-like domain Mr Bayes output.nex.con.tre
2-oxopent-4-enoate hydratase Mr Bayes output.nex.con.tre
2-hydroxymuconic semialdehyde hydrolase Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase N-terminal domain with extra-domain region Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase N-terminal domain Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase N-terminal domain with intra-domain region Mr Bayes output.nex.con.tre
acetaldehyde dehydrogenase Mr Bayes output.nex.con.tre
catechol 2,3-dioxygenase Mr Bayes output.nex.con.tre
ferredoxin-like peptide Mr Bayes output.nex.con.tre
Depth of O2 penetration in Treponema primitia O2/aromatic gradient cultures
Depth of O2 penetration in Treponema primitia O2:aromatic gradient cultures.xlsx
Raw growth (OD) data.xlsx
2-hydroxymuconic semialdehyde hydrolase original MUSCLE alignment.txt
2-oxopent-4-enoate hydratase original MUSCLE alignment.txt
4-hydroxy-2-oxopentanoate aldolase DmpG-like domain original MUSCLE alignment.txt
4-hydroxy-2-oxopentanoate aldolase HMGL-like domain original MUSCLE alignment.txt
4-hydroxy-2-oxopentanoate aldolase original MUSCLE alignment.txt
acetaldehyde dehydrogenase dimerisation domain original MUSCLE alignment.txt
acetaldehyde dehydrogenase NAD binding domain original MUSCLE alignment.txt
acetaldehyde dehydrogenase original MUSCLE alignment.txt
catechol 2,3-dioxygenase C-terminal domain original MUSCLE alignment.txt
catechol 2,3-dioxygenase C-terminal domain with extra-domain region original MUSCLE alignment.txt
catechol 2,3-dioxygenase C-terminal domain with intra-domain region original MUSCLE alignment.txt
catechol 2,3-dioxygenase N-terminal domain original MUSCLE alignment.txt
catechol 2,3-dioxygenase N-terminal domain with extra-domain region original MUSCLE alignment.txt
catechol 2,3-dioxygenase N-terminal domain with intra-domain region original MUSCLE alignment.txt
catechol 2,3-dioxygenase original MUSCLE alignment.txt
ferredoxin-like peptide original MUSCLE alignment.txt