title: The ICEXTDof Azoarcus sp. CIB, an integrative and conjugative element with aerobic and anaerobic catabolic properties.
abstract: Integrative and conjugative elements (ICE) play a major role in aerobic degradation of aromatic compounds, but they have not yet been shown to be involved in anaerobic degradation. We have characterized here the ICEXTDelement which endows to the beta-proteobacterium Azoarcus sp. CIB with the ability to utilize aromatic hydrocarbons. The core region of ICEXTD, which shows a remarkable synteny with that of ICEclc-like elements, allows its own intracellular and intercellular mobility. ICEXTDintegrates at the tRNAGly of the host chromosome, but it can also excise to produce a ready to transfer circular form. The adaptation modules of ICEXTDrepresent a unique combination of gene clusters for aerobic (tod genes) and anaerobic (bss-bbs and mbd genes) degradation of certain aromatic hydrocarbons, e.g., toluene, m-xylene and cumene. Transfer of ICEXTDto other Azoarcus strains, e.g., A. evansii, confers them the ability to degrade aromatic hydrocarbons both aerobically and anaerobically. Interestingly, ICEXTDallows Cupriavidus pinatubonensis, a bacterium unable to degrade anaerobically aromatic compounds, to grow with m-xylene under anoxic conditions. Thus, ICEXTDconstitutes the first mobile genetic element able to expand the catabolic abilities of certain bacteria for the removal of aromatic hydrocarbons either in the presence or absence of oxygen.
authors.affiliation: Environmental Biology Department, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Zamarro
authors.affiliation: Environmental Biology Department, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain.
authors.forename: Zaira
authors.initials: Z
authors.lastname: Martín-Moldes
authors.affiliation: Environmental Biology Department, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Díaz
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D020627:Azoarcus / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D014050:Toluene / Q000378:metabolism; D014992:Xylenes / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D006841:Hydrocarbons, Aromatic; D014992:Xylenes; D014050:Toluene; C031285:3-xylene