1. © Phylogenetic Diversity And Activity Of Aerobic Heterotrophic Bacteria From A Hypersaline Oil-Polluted Microbial Mat Abed, RMM; Zein, B; Al-Thukair, A; de Beer, D ELSEVIER GMBH, URBAN FISCHER VERLAG, SYSTEMATIC AND APPLIED MICROBIOLOGY; pp: 319-330; Vol: 30 King Fahd University of Petroleum & Minerals http://www.kfupm.edu.sa Summary The diversity and function of aerobic heterotrophic bacteria (AHB) in cyanobacterial mats have been largely overlooked. We used culture-dependent and molecular techniques to explore the species diversity, degradative capacities and functional guilds of AHB in the photic layer (2 mm) of an oil-polluted microbial mat from Saudi Arabia. Enrichment isolation was carried out at different salinities (5% and 12%) and temperatures (28 and 45 degrees C) and on various substrates (acetate, glycolate, Spirulina extract and crude oils). Counts of most probable number showed a numerical abundance of AHB in the range of 1.15-8.13 x 10(6) cells g(-1) and suggested the presence of halotolerant and thermotolerant populations. Most of the 16S rRNA sequences of the obtained clones and isolates were phylogenetically affiliated to the groups Gammaproteobacteria, Bacteriodetes and Alphaproteobacteria. Groups like Deltaproteobacteria, Verrucomicrobia, Planctomycetes, Spirochaetes, Acidobacteria and Deinococcus-Thermus were only detected by cloning. The strains isolated on acetate and glycolate belonged to the genera Marinobacter, Halomonas, Roseobacter and Rhodobacter whereas the strains enriched on crude oil belonged to Marinobacter and Alcanivorax. Members of the Bacteriodetes group were only enriched on Spirulina extract indicating their specialization in the degradation of cyanobacterial dead cells. The substrate spectra of representative strains showed the ability of all AHB to metabolize cyanobacterial photosynthetic and fermentation products. However, the unique in situ conditions of the mat apparently favored the Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

2. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. © enrichment of versatile strains that grew on both the cyanobacterial exudates and the hydrocarbons. We conclude that AHB in cyanobacterial mats represent a diverse community that plays an important role in carbon-cycling within microbial mats. (c) 2006 Elsevier GmbH. All rights reserved. References: ABED RMM, 2001, ENVIRON MICROBIOL, V3, P53 ABED RMM, 2002, APPL ENVIRON MICROB, V68, P1674 ABED RMM, 2005, INT BIODETER BIODEGR, V55, P29, DOI 10.1016/j.ibiod.2004.07.001 ABED RMM, 2006, FEMS MICROBIOL ECOL, V57, P290, DOI 10.1111/j.1574-6941.2006.2006.00113.x AMANN RI, 1995, MICROBIOL REV, V59, P143 ANDERSON KL, 1987, APPL ENVIRON MICROB, V53, P2343 BATESON MM, 1988, APPL ENVIRON MICROB, V54, P1738 CANFIELD DE, 1991, SCIENCE, V251, P1471 CAUMETTE P, 2004, OPHELIA, V58, P133 CHANG YJ, 2000, J MICROBIOL METH, V40, P19 CLARKE KR, 1983, J MICROBIOL METH, V1, P133 DEOTEYZA TG, 2004, OPHELIA, V58, P233 EPSTEIN SS, 1995, MAR ECOL-PROG SER, V117, P289 GALINSKI EA, 1995, ADV MICROBIOL PHYSL, V37, P273 GAUTHIER MJ, 1992, INT J SYST BACTERIOL, V42, P568 GLUD RN, 1992, J PHYCOL, V28, P51 HEIJTHUIJSEN JHFG, 1986, FEMS MICROBIOL ECOL, V38, P57 HUU NB, 1999, INT J SYST BACTERI 2, V49, P367 JONKERS HM, 2003, AQUAT MICROB ECOL, V30, P127 JORGENSEN BB, 1992, PROTEROZOIC BIOSPHER, P287 KIRKWOOD AE, 2006, MICROB ECOL, V51, P4, DOI 10.1007/s00248-004- 0058-y 24. KOLMONEN E, 2004, AQUAT MICROB ECOL, V36, P201 25. LLOBETBROSSA E, 1998, APPL ENVIRON MICROB, V64, P2691 26. LUDWIG W, 2004, NUCLEIC ACIDS RES, V32, P1363, DOI 10.1093/nar/gkh293 27. MADIGAN MT, 2000, BROCK BIOL MICROORGA 28. MUSAT F, 2004, OPHELIA, V58, P217 29. MUSAT F, 2006, ENVIRON MICROBIOL, V8, P1834, DOI 30. 10.1111/j.1462-2920.2006.01069.x 31. MUSAT N, 2006, SYST APPL MICROBIOL, V29, P333, DOI 32. 10.1016/j.syapm.2005.12.006 33. MUYZER G, 1995, ARCH MICROBIOL, V164, P165 34. NOLD SC, 1996, APPL ENVIRON MICROB, V62, P4598 35. PAERL HW, 1993, LIMNOL OCEANOGR, V38, P1150 Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

3. 36. 37. 38. 39. 40. 41. 42. © RADWAN SS, 2000, INT BIODETER BIODEGR, V46, P129 RADWAN SS, 2001, FEMS MICROBIOL LETT, V198, P99 RANCHOUPEYRUSE A, 2006, ENVIRON MICROBIOL, V8, P1590, DOI 10.1111/j.1462-2920.2006.01050.x REISENBACH H, 1991, PROKARYOTES RUSH A, 2003, FEMS MICROBIOL ECOL, V44, P89 SANCHEZ O, 2005, MICROB ECOL, V50, P580, DOI 10.1007/s00248-005- 5061-4 43. SANTEGOEDS CM, 1996, APPL ENVIRON MICROB, V62, P3922 44. SIGALEVICH P, 2000, APPL ENVIRON MICROB, V66, P5013 45. SIGALEVICH P, 2000, APPL ENVIRON MICROB, V66, P5019 46. STAL LJ, 1995, NEW PHYTOL, V131, P1 47. STAL LJ, 1997, FEMS MICROBIOL REV, V21, P179 48. SYUTSUBO K, 2001, ENVIRON MICROBIOL, V3, P371 49. TEISER MLO, 1993, EXTRACELLULAR LOW MO 50. VANHANNEN EJ, 1999, APPL ENVIRON MICROB, V65, P795 51. WARD DM, 1990, NATURE, V345, P63 52. WIDDEL F, 1992, PROKARYOTES HDB BIOL, P3353 53. WIELAND A, 2000, MAR ECOL-PROG SER, V196, P87 54. YAKIMOV MM, 1998, INT J SYST BACTERI 2, V48, P339 55. ZWART G, 2002, AQUAT MICROB ECOL, V28, P141 For pre-prints please write to: rabed@mpi-bremen.de Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa