wwwUST -- St. Thomas internet homeSearchA to ZMyUST -- Personalized web portals for UST students
Department of Biology University of St. Thomas, Minnesota USA

 

Jayna L. Ditty, Ph.D

Research in Microbiology

 

Professional Interests:

  • Molecular mechanism of the Synechococcus elongatus prokaryotic circadian clock

  • Photic entrainment of the Synechococcus elongatus circadian clock

  • Chemotaxis towards and degradation of aromatic hydrocarbons in Pseudomonas putida F1

  • Efficacy of novel antimicrobial compounds

 

 
Synechococcus elongatus PCC 7942. This single celled cyanobacterium is the model organism for the study of circadian rhythms in prokaryotes.
 

 

 

 

Recent Publications and Presentations
Names in bold denote student research collaborators

 
 

Ebner, D., J. Culhane, M.D. Haustein, J.L. Ditty, and J.T. Ippoliti. (2005) Synthesis of a novel oxazolidinone antimicrobial agent. (in preparation)

 

 

Canales, S.R., J.L. Ditty, E.M. Clerico, and S.S. Golden. (2005) Detection of rhythmic bioluminescence from luciferase reporters in cyanobacteria. Methods in Molecular Biology (in press)

Clerico, E.M., J.L. Ditty, and S.S. Golden. (2005) Specialized techniques for site-directed mutagenesis in cyanobacteria. Methods in Molecular Biology (in press)

Parales, R.E., and J.L. Ditty. (2005) Laboratory evolution of catabolic enzymes and pathways. Current Opinion in Biotechnology 16:315-325.

Ditty, J.L., S.R. Canales, B.E. Anderson, S.B. Williams, and S.S. Golden. (2005) Stability of the Synechococcus elongatus PCC 7942 circadian clock under directed anti-phase expression of the kai genes. Microbiology 151: 2605-2613.

Ditty, J.L., S.B. Williams, and S.S. Golden. (2003) A cyanobacterial circadian timing mechanism. Annual Review Genetics 37: 513-43.

Nair, U., J.L. Ditty, Y. Xu, H. Min, and S.S. Golden. (2002) Roles for sigma factors in global circadian regulation of the cyanobacterial genome. Journal of Bacteriology 184:3530-3538.

Ditty, J.L., and C.S. Harwoood. (2002) Charged amino acids conserved in the aromatic acid/H(+) symporter family of permeases are required for 4-hydroxybenzoate transport by PcaK from Pseudomonas putida. Journal of Bacteriology 184:1444-1448.

Parales, R.E., J.L. Ditty, and C.S. Harwood. (2000) Toluene-degrading bacteria are chemotactic towards the environmental pollutants benzene, toluene, and trichloroethylene.  Applied and Environmental Microbiology  66:4098-4104.

Ditty, J.L., and C.S. Harwood. (1999) Conserved cytoplasmic loops are important for both the transport and chemotaxis functions of PcaK, a 12 membrane-spanning protein from Pseudomonas putida. Journal of Bacteriology 181: 5068-5074.

Ditty, J.L., A.C. Grimm, and C.S. Harwood. (1988) Identification of a chemotaxis gene region from Pseudomonas putida. FEMS Microbiology Letters 159: 267-273.

Harwood, C.S., N.N. Nichols, M.-K. Kim, J.L. Ditty, and R.E. Parales. (1994) Identification of the pcaRKF gene cluster from Pseudomonas putida: Involvement  in chemotaxis, biodegradation, and transport of 4-hydroxybenzoate. Journal of Bacteriology 176: 6470-6488.

 

 

 
Pseudomonas putida F1 response to toluene. As the aromatic hydrocarbon toluene diffuses out of the capillary, P. putida F1 senses and responds to the molecule by swimming towards and accumulating at the tip of the capillary.  (40X magnification)
 

 

 

 

 

Grant Awards
 

Starter Grant, National Science Foundation MCB-0329366.  Project title: Circadian Rhythms in Cyanobacteria.

 Research Assistance Grant, University of St. Thomas Faculty Development program.  Project title: How do bacteria tell time? Characterizing Regulatory Elements in Circadian Clock Genes in Cyanobacteria.

 

 

 

Student Researchers
 
 
 

2005

Christina Bye: Identification of trans regulatory elements involved in the expression of the circadian clock genes kaiBC in Synechococcus elongatus PCC 7942.

 

Eric Chapman: Identification of a putative serine/threonine phosphatase in Synechococcus elongatus PCC 7942.

Chelsea Grolla: Effects of photoperiod on the Synechococcus elongatus PCC 7942 circadian mechanim.

Tamara Johnson: Searching for cyanobacterial regulators involved in kaiBC gene expression.

Tucker Johnson: The role of phosphatases in nature’s timepiece.

Janet Rollefson: Methyl-accepting chemotaxis proteins involved in chemotaxis to toluene.

Sheila Stegora: Construction of a kaiA luciferase reporter fusion for Synechococcus elongatus PCC 7942.

Andrew Walker: Identification of cyanobacterial clock mutants.

Tyler Winkelman: Synthesis of a novel antimicrobial agent.     

 
 

Circadian rhythms in S. elongatus are easily measured by bioluminescence reporters.  The blue trace is a wild-type circadian pattern of bioluminescence expression.  The red, green, and yellow traces are kaiA, kaiB, and kaiC mutations respectively.
 

 

 
2004
 

Breanne Anderson: Pervasiveness of an anti-phase kai circadian clock.

Christina Bye:  Characterization of the promoter of the Synechococcus elongatus circadian clock

Kevin Piper:  Effectiveness of a novel anti-microbial compound

 

 

  

 


                                      

         

         

USThomeshield.gif (1004 bytes) © October 2005  University of St. Thomas