Juan Gonzalez

Juan Gonzalez

Professor - Biological Sciences
Dean of Graduate Education
 
972-883-2526
RL2704
Tags: Microbiology Biology

Professional Preparation

Postdoctoral Fellow - Department of Biology
Massachusetts Institute of Technology - 1996
Ph.D. - Microbiology and Molecular Genetics
University of California Los Angeles - 1991
B.S - Microbiology and Public Health
Michigan State University - 1985

Research Areas

Research Interests
Members of the rhizobia are distinguished for their ability to establish a nitrogen-fixing symbiosis with leguminous plants. While many details of this relationship remain a mystery, much effort has gone into elucidating the mechanisms governing bacterium-host recognition and the events leading to symbiosis. Several signal molecules, including plant-produced flavonoids and bacterially produced nodulation factors and exopolysaccharides, are known to function in the molecular conversation between the host and the symbiont.   Work by several laboratories has shown that an additional mode of regulation, quorum sensing, intercedes in the signal exchange process and perhaps plays a major role in preparing and coordinating the nitrogen-fixing rhizobia during the establishment of the symbiosis. Rhizobium leguminosarum, for example, carries a multitiered quorum-sensing system that represents one of the most complex regulatory networks identified for this form of gene regulation.   This review focuses on the recent stream of information regarding quorum sensing in the nitrogen-fixing rhizobia. Seminal work on the quorum-sensing systems of R. leguminosarum bv. viciae, R. etli, Rhizobium sp. strain NGR234, Sinorhizobium meliloti, and Bradyrhizobium japonicum is presented and discussed. The latest work shows that quorum sensing can be linked to various symbiotic phenomena including nodulation efficiency, symbiosome development, exopolysaccharide production, and nitrogen fixation, all of which are important for the establishment of a successful symbiosis.   Many questions remain to be answered, but the knowledge obtained so far provides a firm foundation for future studies on the role of quorum-sensing mediated gene regulation in host-bacterium interactions.

Publications

Hoang, H. and González, J.E. (2006). The Regulation of Motility by the Sinorhizobium meliloti Sin/ExpR Quorum Sensing System. (Submitted, Journal of Bacteriology). 2006 - Publication
González, J.E. and Keshavan, N. (2006) Messing with Quorum Sensing. (Submitted, Microbiology and Molecular Biology Reviews). 2006 - Publication
Marketon, M., Gronquist, M.R., Eberhard, A. and González, J.E. (2006). Quorum Sensing Controls Conjugal Transfer in Sinorhizobium meliloti Rm41. (In press, Journal of Bacteriology). 2006 - Publication
González, J.E. (2005). Quorum Sensing. McGraw-Hill Yearbook of Science & Technology, 37-45. 2005 - Publication
Llamas-Company, I., Bejar, V., Martinez-Canovas, M.J., González, J.E. (2005) Quorum Sensing in Halophilic Bacteria: Detection of N-Acyl-Homoserine Lactones in Exopolysaccharide-Producing Halomonas species. Extremophiles, 10 (1):17-26. 2005 - Publication
Keshavan N. and González, J.E. (2005). Host-Plant Interference in Sinorhizobium meliloti Quorum Sensing. Journal of Bacteriology, 187(24):8427-8436. 2005 - Publication
Llamas-Company, I., González, J.E. (2004). Sinorhizobium meliloti as an Indicator for the Specific Detection of Long-Chain AHLs. Applied and Environmental Microbiology, 70(6):3715-3723. 2004 - Publication
Hoang, H. Becker, A. and González, J.E. (2004). The LuxR Homolog ExpR, in Combination with the Sin Quorum Sensing System, Plays a Central Role in Sinorhizobium meliloti Gene Expression. Journal of Bacteriology, 186(16):5460-5472. 2004 - Publication
González, J.E. and Marketon, M. (2003). Quorum Sensing in the Nitrogen Fixing Rhizobia. Microbiology and Molecular Biology Reviews, 67(4):574-592. 2003 - Publication
Marketon, M., Glenn, S., Eberhard, A. and González, J.E. (2003). The Role of Quorum Sensing on Exopolysaccharide Production in Sinorhizobium meliloti. Journal of Bacteriology, 185(1):325-331. 2003 - Publication

Appointments

Associate Dean
University of Texas at Dallas [2003–Present]
School of Natural Sciences & Mathematics
Associate Professor
University of Texas at Dallas [2002–Present]
Assistant Professor
University of Texas at Dallas [2002–Present]

Projects

Invited Talks
2018–2018 Long-Range RNA/RNA Interactions Affect IS10 Transposase Expression. Annual Meeting of the American Society for Microbiology, Anaheim, CA. May 1990. Rhizobium/Alfalfa Symbiosis. Massachusetts Institute of Technology, Cambridge, MA, September 1994. Role of Exopolysaccharides in the Rhizobium/Alfalfa Symbiosis. University of Pittsburgh, Pittsburgh, PA, January 1996. Juan E. González Analysis of the Signaling Interactions Necessary for the Alfalfa Nodule Invasion by Rhizobium meliloti. University of California, Berkeley, CA, February 1996. Genetic and Biochemical Analysis of Rhizobium Exopolysaccharides and Their Role in Alfalfa Nodule Invasion. Michigan State University, East Lansing, MI, March 1996. Rhizobium/Alfalfa Symbiosis. University of Texas at Dallas, Dallas, TX, April 1996. Analysis of the Signaling Interactions Necessary for the Alfalfa Nodule Invasion by Rhizobium meliloti. University of Louisville, Louisville, KY, May 1996. Genetic and Biochemical Analysis of Rhizobium Exopolysaccharides and their Role in Alfalfa Nodule Invasion. Microbial Polysaccharides of Medical, Agricultural and Industrial Importance. FASEB Research Conference, Copper Mountain, Colorado, June 1997. Rhizobium Exopolysaccharides. XVI Microbiology Congress, Granada, Spain, September 1999. Cell-Cell Signaling in Rhizobium meliloti. Louisiana State University Medical Center, Shreveport, Louisiana, March 2000. Commonalities Between the Symbiotic State of the Rhizobia and the Pathogenic State of the Brucellae in Mammalian Cells. Joint lecture with R. Martin Roop, LSUMC. Louisiana State University Medical Center, Shreveport, Louisiana, March 2000. Rhizobium exopolysaccharides. Microbial Polysaccharides of Medical, Agricultural and Industrial Importance. FASEB Research Conference, Copper Mountain, Colorado, August 2000. Molecular Signaling in the Alfalfa-Sinorhizobium meliloti Symbiotic Interactions. University of Maine, September 2000. Role of Molecular Signals in the Sinorhizobium meliloti-Alfalfa Symbiosis. University of Guanajuato, Mexico, October 2001. Identification of a Putative Periplasmic Iron-Binding Gene Required for the Sinorhizobium meliloti-Alfalfa Symbiosis. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2002. Characterization of Quorum Sensing in Sinorhizobium meliloti. University of North Texas, Denton, Texas, September, 2002. 40th Anniversary Salute to UTD Sciences. Topics in UTD Biology. University of Texas at Dallas, September 2002. Characterization of Quorum Sensing in Sinorhizobium meliloti. University of Puerto Rico, Mayagüez, Puerto Rico, November 2002. Quorum Sensing in Sinorhizobium meliloti. Purdue University, West Lafayette, Indiana, April 2003. Quorum Sensing in Sinorhizobium meliloti. University of Minnesota, Minneapolis, Minnesota, May 2003. Quorum Sensing in Sinorhizobium meliloti. University of North Texas, Denton, Texas September 2003. Characterization of Quorum Sensing in Sinorhizobium meliloti. University of Nevada, Las Vegas, Nevada, October 2003. Characterization of Quorum Sensing in Sinorhizobium meliloti. University of Texas at Arlington, Arlington, Texas, October 2003. Characterization of Quorum Sensing in Sinorhizobium meliloti. Texas Branch-American Society for Microbiology, Texas A&M University, College Station Texas, November 2003. Characterization of Quorum Sensing in Sinorhizobium meliloti. Northwestern University, Evanston, Illinois, November 2003. The Role of Quorum Sensing in the Sinorhizobium meliloti-Alfalfa Symbiosis. Colorado State University, Colorado, October 2004. The Role of Quorum Sensing in Plant-Bacterial. Texas Branch American Society for Microbiology, Houston, Texas, November 2004. Role of Quorum Sensing in the Symbiotic Interaction between Sinorhizobium meliloti and Alfalfa. Department of Biology, University of Guanajuato, February 2005. Control of Quorum Sensing in the Symbiotic Interaction Between Sinorhizobium meliloti and Alfalfa. 12th International Congress on Molecular Plant-Microbe Interactions, Cancun, Mexico, July 2005. Control of Quorum Sensing in the Symbiotic Interaction Between Sinorhizobium meliloti and Alfalfa. 13th International Congress of Bacteriology and Applied Microbiology (IUMS), San Francisco, California July 2005. The Role of Quorum Sensing in Plant-Bacterial Interactions. Indiana University, Bloomington, Indiana, April 2006.

Additional Information

Honors
  • National Science Foundation Career Award, 1998-03.
  • 1991-95, Jane Coffin Childs Memorial Fund Postdoctoral Fellowship.
  • 1989-90, University of California President's Dissertation Year Fellowship.
  • 1990, Conference Travel Award (UCLA).
  • 1988-89, Rittenberg Award for Outstanding Microbiology Graduate Research.
  • 1987-88, Research Assistantship/Mentorship Award.
  • 1988, Conference Travel Award (UCLA).
  • 1986-87, Graduate Pre-doctoral Fellowship.
  • 1985-86, Graduate Pre-doctoral Fellowship.
Abstracts and Presentations

1) Simons, R.W., Case, C.C., and González, J.E. Translational Control of IS10 Transposition. Translational control meeting, Cold Spring Harbor Laboratory, Long Island, NY, July 1987. Juan E. González

2) González, J.E. and Simons, R.W. Long Range RNA/RNA interactions in the IS10 Transposase mRNA. 1988 UCLA-Arrowhead Genetics Conference, Arrowhead, CA, January 1988.

3) González, J.E., and Wisnieski, B.J. An Endosomal Model for Acid-Triggering of Diphtheria Toxin Translocation. Abstract of the Annual Meeting of the American Society for Microbiology, Miami, FL. 1988, 41.

4) González, J.E., and Simons, R.W. Long-Range RNA/RNA Interactions Affect IS10 Transposase Expression. Abstract of the Annual Meeting of the American Society for Microbiology, Miami, FL. 1988, 178.

5) González, J.E., and Simons, R.W. Long Range RNA/RNA Interactions in the IS10 Transposase mRNA. Abstract of the Annual Meeting of the American Society for Microbiology, Southern California Branch, San Diego, CA. November 1988.

6) González, J.E., and Simons, R.W. Long Range RNA/RNA Interactions in the IS10 tnp mRNA Affect Pairing with the IS10 Antisense RNA. Abstract of the Annual Meeting of the American Society for Microbiology, Anaheim, CA. 1990, 184.

7) Ma, C., González, J.E., Case, C.C. Sonnabend, T., Rayner, J., and Simons. R.W. Post-Transcriptional Control of IS10 Transposase Expression; Antisense RNA Binding and Other Conformational Changes, Affecting RNA Stability and Translation. Post-Transcriptional Control of Gene Expression NATO/EEC Meeting, Goslar, F.R.G, April 1990.

8) Simons, R.W., Ma, C., Case, C.C., and González, J.E. IS10 Antisense RNA Control: A Model System for the Design of Efficient and Specific Artificial Antisense RNAs. 1991 Keystone Symposia, Gene regulation by antisense RNA and DNA, Journal of Cellular Biochemistry, Supplement 15D, page 3.

9) González, J.E., Reuber, T.L., Glucksmann, A., Marra, A. and Walker, G.C. Genetic and Biochemical Analyses of an Acidic Exopolysaccharide Required for Nodule Invasion by Rhizobium meliloti. 9th International Congress on Nitrogen Fixation. Cancun, Mexico. December 1992.

10) González, J.E., Reuber, T.L., Glucksmann, A., Marra, A. and Walker, G.C. An Acidic Exopolysaccharide Required for Nodule Invasion by Rhizobium meliloti. Keystone Symposia, The Extracellular Matrix of Plants: Molecular, Cellular and Developmental Biology. January 1993.

11) González, J.E., York, G.M., Liu, M., Cheng, H.P. and Walker, G.C. The Role of Succinoglycan in Alfalfa Nodulation. 7th International Symposium on Molecular Plant-Microbe Interactions. Edinburgh, Scotland. June 1994.

12) Cheng, H.P., González, J.E., Ichige, A., LeCour, L.F., Willis, L.B., York, G.M. and Walker, G.C. Genetic Analysis of Alfalfa Root Nodule Invasion by Rhizobium meliloti. 10th International Congress on Nitrogen Fixation. Saint Petersburg, Russia. May 1995.

13) González, J. E. and Walker, G. C. Low Molecular Weight EPS II Promotes Nodule Invasion in Medicago sativa. Molecular Genetics of Bacteria and Phages. Cold Spring Harbor Laboratory, Long Island, New York. August 1995.

14) Mendrygal, K, and González, J.E. Rhizobial Exopolysaccharides. 97th American Society for Microbiology, Miami, Florida, May 1998.

15) Hakala, K. Marketon, M. and González, J.E. Characterization of Quorum Sensing in Rhizobium. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1998.

16) Worley, E. and González, J.E. Rhizobium Exopolysaccharides and Their Role in Host Specificity. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1998.

17) Mendrygal, K. and González, J.E. Rhizobium Exopolysaccharides: Synthesis and Symbiotic Function. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1998.

18) Worley, E. and González, J.E. Rhizobium Exopolysaccharides and Their Role in Host Specificity. Lost Pines Molecular Biology Conference, Smithville, Texas. October 1998.

19) Castellano-Torres, L. and González, J.E. Rhizobium Exopolysaccharides: Lipid Anchor Cycling. Lost Pines Molecular Biology Conference, Smithville, Texas. October 1998.

20) Marketon, M and González, J.E. Characterization of Quorum Sensing in Rhizobium meliloti. Lost Pines Molecular Biology Conference, Smithville, Texas. October 1998.

21) Mendrygal, K. and González, J.E. Environmental Regulation of Exopolysaccharide Production by Rhizobium meliloti. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1999.

22) Castellano-Torres, L. and González, J.E. Lipid Carrier Cycling During Biosynthesis of Succinoglycan, a Symbiotically Important Exopolysaccharide of Rhizobium meliloti. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1999.

23) Worley, E. and González, J.E. Differential Display in Rhizobium meliloti. Wind River Conference on Procaryotic Biology. Estes Park, Colorado, June 1999.

24) Marketon, M and González, J.E. Characterization of Quorum Sensing in Rhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 1999.

25) Marketon, M and González, J.E. Characterization of Quorum Sensing in Rhizobium meliloti. American Society for Microbiology, Los Angeles, CA, May 2000.

26) Keshavan, N and González, J.E. Role of Quorum Sensing in Symbiotic Nitrogen Fixation. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2000.

27) Smith, S and González, J.E. Characterization of Succinoglycan Biosynthesis Mutants. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2000.

28) Martinez-Checa, F and González, J.E. Succinoglycan Biosynthetic Complex. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2000.

29) Marketon, M and González, J.E. Characterization of Quorum Sensing in Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2000.

30) Martinez-Checa, F and González, J.E. Role of Carbohydrate Metabolism in the Alfalfa-Sinorhizobium meliloti Symbiosis. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2001.

31) Glenn, S and González, J.E. Characterization of Exopolysaccharide Biosynthesis Mutants. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2001.

32) Hoang, H. and González, J.E. Identification of a Putative Periplasmic Iron-Binding Gene Required for Symbiosis. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2001.

33) Marketon, M.M. and González, J. E. Characterization of Quorum Sensing in Sinorhizobium meliloti. ASM Conference on Cell-Cell Communication in Bacteria, Snowbird, Utah, July 2001.

34) Keshavan N.D. and González, J.E. Host Plant Interference in Sinorhizobium meliloti AHL Production. ASM Conference on Cell-Cell Communication in Bacteria, Snowbird, Utah, July 2001.

35) Glenn, S and González, J.E. Characterization of Exopolysaccharide Biosynthesis Mutants. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2002.

36) Marketon, M.M. and González, J. E. Quorum Sensing Controls Exopolysaccharide Production in Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2002. Ms. Marketon was awarded first prize in the student talk's category.

37) Llamas-Company, I. and González, J. E. Identification of the Putative Plant Receptor for the Biologically-Active Succinoglycan Oligosaccharide of Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2002.

38) Hoang, H. and González, J.E. Expression Profile Analysis of the Symbiotically Important Sin Quorum Sensing System Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003. Ms. Hoang was awarded first prize in the student talk's category.

39) Keshavan N.D. and González, J.E. Host Plant Interferes with Sinorhizobium meliloti's AHL Production. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003.

40) Glenn, S, Fenney, M. and González, J.E. Regulation of KPS Production, a Symbiotically Important Polysaccharide. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003.

41) Llamas-Company, I., Keshavan N.D. and González, J. E. Sinorhizobium meliloti as an Indicator for Specific Detection of Long-Chain AHLs Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003.

42) Patankar, A and González, J.E. Quorum Sensing in Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003.

43) Fenney, M., Glenn, S. and González, J.E. KPS, a Capsular Polysaccharide Essential for Nodule Invasion in Alfalfa. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2003.

44) Glenn, S, Fenney, M. and González, J.E. Quorum Sensing Controls Low Molecular eight Succinoglycan Production in Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2004.

45) Hoang, H. Ingram, J. and González, J.E. The Sin/ExpR Quorum Sensing System Controls Flagella Synthesis and Motility in Sinorhizobium meliloti. Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 2004.

46) Patankar, A. and González, J.E. Quorum Sensing in Sinorhizobium meliloti. Texas Branch American Society for Microbiology, Houston, Texas, November 2004.

47) Glenn, S.A. and González, J.E. Quorum Sensing Controls Low Molecular Weight Succinoglycan Production in Sinorhizobium meliloti. Texas Branch American Society for Microbiology, Houston, Texas, November 2004.

48) Hoang, H. Ingram, J. and González, J.E. Quorum Sensing as a Central Regulator in Sinorhizobium meliloti. Texas Branch American Society for Microbiology, Houston, Texas, November 2004.

49) Hoffman, J. and González, J.E. Regulation of Quorum Sensing in Sinorhizobium meliloti. Texas Branch American Society for Microbiology, Houston, Texas, November 2004.

50) Affolter, C.W., Glenn, S.A. and González, J.E. Quorum Sensing Controls the Synthesis of Cyclic b(1, 2)-Glucan in Sinorhizobium meliloti. Microbial Pathogenesis & Host Response Meeting, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, September, 2005

Departmental Committees
  • 2000-2001- Member of the Molecular & Cell Biology Chair Search Committee.
  • November 2000-2002- Chair, Graduate Education Committee.
  • 1996-present- Academic advisor for 50 of our B.S. in biology students.
  • 1996-present- Member of the Department of Molecular and Cell Biology Graduate Education Committee.

News Articles

UTD Scientist Wins $2.1 Million in Grants To Study Communication Among Bacteria
UTD Scientist Wins $2.1 Million in Grants To Study Communication Among Bacteria RICHARDSON, Texas (July 18, 2005) – A scientist at The University of Texas at Dallas (UTD) has won federal funding of $2.1 million for studies of how bacterial cells communicate with each other – fundamental research that could lead to the development of new methods to halt the spread of deadly infectious diseases. 

Dr. Juan E. González, associate professor in the Department of Molecular and Cell Biology at UTD, received monies from two federal agencies – a National Institutes of Health (NIH) grant in the amount of $1.5 million over five years and a National Science Foundation (NSF) award for $600,000 over three years.

Activities

Professional Societies
  • American Society for Microbiology, 1983-present.
  • American Association for the Advancement of Science, 1989-present.
  • International Society for Molecular Plant-Microbe Interactions, 1992-present.
  • International Who's Who of Professionals, 1998.

Funding

Quorum Sensing Interference
$100,000 - Advanced Research Program [2006–2008]
Quorum Sensing in Sinorhizobium meliloti
$240,000 - Research Supplement [2006–2009]
Summer Research Undergraduate Experiences.
$10,000 - National Science Foundation (MCB-0212537) Supplement [2005–2005]
Role of Exopolysaccharides in Sinorhizobium meliloti/Alfalfa Symbiosis.
$580,000 - National Science Foundation (MCB-0517162) [2005–2008]
Quorum Sensing in Sinorhizobium meliloti
$1,495,000 - National Institutes of Health (1R01GM069925) [2005–2010]