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Natural Resource Sciences



Microbiology


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Dr. Brian T. Driscoll
Associate Professor 

B.Sc. McMaster University (1988) 
Ph.D. McMaster University (1995) 
Research Associate- University of Minnesota (1994-95) 
Assistant Professor- McGill University, Macdonald Campus (1996-2002) 
Associate Professor- McGill University, Macdonald Campus (2002-present)
 


 
 
 
Research is focused on understanding the exchange of nutrients that occurs between plants and bacteria during symbiotic nitrogen fixation. Symbiotic nitrogen fixation occurs when bacteria (Rhizobia) and legume plants interact to form nodules filled with bacteria on the plant roots. The bacteria within the root nodule cells differentiate into a form known as 'bacteroids', and then are able to fix nitrogen (convert nitrogen gas into ammonium). Nitrogen fixation is catalyzed by nitrogenase - an enzyme which only certain procaryotic (bacterial and archaeal) organisms possess. An adequate supply of 'fixed' nitrogen (i.e., ammonium, amino acids) is critical for all cells, however, as it is a key component in many biological molecules (i.e., DNA and proteins). Symbiotic nitrogen fixation is a major source of the 'fixed' nitrogen required by all cells. The relationship between Rhizobia bacteria and legume plants is considered symbiotic, as there appears to be a mutually beneficial exchange of nutrients between the partners. In exchange for 'fixed' nitrogen, the plant supplies the bacteria with organic acids as energy source. The bacteroids require a great deal of energy to 'fix' nitrogen, therefore it is in the plant's best interest to allow nitrogen fixation to proceed effectively.  Sucrose is translocated from the leaves to the root nodule cells, where enzymes convert it to organic acids such as malate. Bacteroids are able to rapidly take up and metabolize organic acids very efficiently. One of the most interesting aspects of bacteroid metabolism is that these cells stop growing, and appear to utlilize all of the energy supplied by the plant to 'fix' nitrogen.
      We are currently investigating carbon metabolism in Sinorhizobium meliloti (previously known as Rhizobium meliloti), which nodulates alfalfa plants. We are also interested in other aspects of microbial physiology, genetics and ecology. In my lab, we use genetic, biochemical, and molecular biological methods to answer our questions.  Other projects involve the study of the nodulation of soybeans by Bradyrhizobium japonicum, and molecular microbial ecological studies involving soil, and pulp and paper wastewater, in collaboration with other researchers.
   
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In MS3-030
Frederic D'Aoust (Ph.D. student)
David Meek (technician)
Jean-Francois Lauzon (M.Sc. student)
Lynda Stewart (Ph.D. student)

   
Instructor:
Bacterial Molecular Genetics MICR-338 (Offered next in Fall 2006)
Microbial Ecology MICR 331 (Winter)
Advanced Microbial Genetics MICR 772 (Fall)
Advanced Microbial Physiology MICR 773 (Winter)
Contributor:
Microbial Physiology Lab (MICR 300)
   

23: Dymov SI, Meek DJ, Steven B, Driscoll BT. Related Articles
Abstract Insertion of transposon Tn5tac1 in the Sinorhizobium meliloti malate dehydrogenase (mdh) gene results in conditional polar effects on downstream TCA cycle genes.
Mol Plant Microbe Interact. 2004 Dec;17(12):1318-27.
PMID: 15597737 [PubMed - indexed for MEDLINE]
22: Chenier MR, Beaumier D, Roy R, Driscoll BT, Lawrence JR, Greer CW. Related Articles
Free in PMC Impact of seasonal variations and nutrient inputs on nitrogen cycling and degradation of hexadecane by replicated river biofilms.
Appl Environ Microbiol. 2003 Sep;69(9):5170-7.
PMID: 12957898 [PubMed - indexed for MEDLINE]
20: Morissette DC, Driscoll BT, Jabaji-Hare S. Related Articles
Abstract Molecular cloning, characterization, and expression of a cDNA encoding an endochitinase gene from the mycoparasite Stachybotrys elegans.
Fungal Genet Biol. 2003 Aug;39(3):276-85.
PMID: 12892640 [PubMed - indexed for MEDLINE]
18: Trosok SP, Luong JH, Juck DF, Driscoll BT. Related Articles
Abstract Characterization of two novel yeast strains used in mediated biosensors for wastewater.
Can J Microbiol. 2002 May;48(5):418-26.
PMID: 12109881 [PubMed - indexed for MEDLINE]
17: Bai Y, D'Aoust F, Smith DL, Driscoll BT. Related Articles
Abstract Isolation of plant-growth-promoting Bacillus strains from soybean root nodules.
Can J Microbiol. 2002 Mar;48(3):230-8.
PMID: 11989767 [PubMed - indexed for MEDLINE]
12: Ip H, D'Aoust F, Begum AA, Zhang H, Smith DL, Driscoll BT, Charles TC. Related Articles
Abstract Bradyrhizobium japonicum mutants with enhanced sensitivity to genistein resulting in altered nod gene regulation.
Mol Plant Microbe Interact. 2001 Dec;14(12):1404-10.
PMID: 11768535 [PubMed - indexed for MEDLINE]
10: Neufeld JD, Driscoll BT, Knowles R, Archibald FS. Related Articles
Abstract Quantifying functional gene populations: comparing gene abundance and corresponding enzymatic activity using denitrification and nitrogen fixation in pulp and paper mill effluent treatment systems.
Can J Microbiol. 2001 Oct;47(10):925-34.
PMID: 11718546 [PubMed - indexed for MEDLINE]
11: Trosok SP, Driscoll BT, Luong JH. Related Articles
Abstract Mediated microbial biosensor using a novel yeast strain for wastewater BOD measurement.
Appl Microbiol Biotechnol. 2001 Aug;56(3-4):550-4.
PMID: 11549036 [PubMed - indexed for MEDLINE]
9: Gauthier F, Neufeld JD, Driscoll BT, Archibald FS. Related Articles
Free in PMC Coliform bacteria and nitrogen fixation in pulp and paper mill effluent treatment systems.
Appl Environ Microbiol. 2000 Dec;66(12):5155-60.
PMID: 11097883 [PubMed - indexed for MEDLINE]
8: Cai GQ, Driscoll BT, Charles TC. Related Articles
Free in PMC Requirement for the enzymes acetoacetyl coenzyme A synthetase and poly-3-hydroxybutyrate (PHB) synthase for growth of Sinorhizobium meliloti on PHB cycle intermediates.
J Bacteriol. 2000 Apr;182(8):2113-8.
PMID: 10735852 [PubMed - indexed for MEDLINE]

 For complete PubMed list, click here

   
Department of Natural Resource Sciences
Macdonald Campus of McGill University 
21 111 Lakeshore Rd 
Ste. Anne de Bellevue, Quebec 
H9X 3V9 
Canada 

To send an e-mail, see the secure e-mail link under my name on the NRS staff page

   
McGill Microbiology
Microbiology graduate studies
Applying to graduate studies in Microbiology at McGill