You are here: Home Faculty Reed Stubbendieck
Document Actions
Reed Stubbendieck

Reed Stubbendieck

Advisor: Dr. Paul Straight

Biochemistry & Biophysics
300 Olsen Blvd. Rm. 435
MS. 2128

College Station , TX 77843
Office Phone: (979) 845-6828

Education:

  1. B.S., Biochemistry & Biological Sciences, University of Nebraska-Lincoln, 2011

Biography:

Entered program in 2011

Research Project:

Bacterial fitness is in part defined by success in competition between species. Mechanisms of competition differ among bacterial species and include contact-dependent inhibition, type VI secretion systems, production of specialized metabolites, and changes in community physiology including biofilm formation and motility. Although these mechanisms are relatively well understood in isolation, how bacteria use them collectively to promote competitive fitness is not well studied. To address fundamental questions relating to the competitive functions of different species, we have developed a model system using two soil bacteria: Bacillus subtilis and Streptomyces sp. Mg1 (S. Mg1). Using this system, we found that linearmycins, produced by S. Mg1, cause lysis of B. subtilis cells and degradation of colony matrix. We obtained B. subtilis mutants spontaneously resistant to linearmycins. Compared to wild type, the mutant strains differ in colony morphology and colony spreading across a solid agar surface. We found that resistance arises from mutations that constitutively activate YfiJK, a two-component system that regulates expression of yfiLMN. We show that the yfiLMN genes, encoding an ABC transporter, are necessary for both linearmycin resistance and the observed changes in colony morphology. These YfiLMN-dependent functions presumably act in concert to promote the competitive fitness of B. subtilis. The linearmycin-resistant mutants revealed an additional competitive function for B. subtilis. We observed that B. subtilis motility is stimulated by an extracellular factor(s) produced by S. Mg1. The linearmycins serve to both disrupt B. subtilis growth and to prevent engulfment of S. Mg1 by the motile competitor. Taken together, our results demonstrate the coordinated regulation of development and antibiotic resistance to promote competitive fitness. 

Broader Impacts of Research Project:

Throughout history, especially beginning in the mid-twentieth century, humans have adapted numerous specialized metabolites produced by microbes for use as therapeutics. Since their inception, antibiotics have been a powerful tool used in science and medicine. We have uncovered a great deal about the cellular functions that they target, mechanisms of resistance, and their application in treating disease. However, our appropriation of these specialized metabolites has led to gaps in our understanding of their ecological function and roles. Additionally, in recent years we’ve begun to appreciate the importance of microbial communities in diverse environmental settings, which includes the human microbiome. The structure and maintenance of a microbial community result from networks of competitive interactions driven by many factors including antibiotics and other specialized metabolites. Currently, whole microbial communities are not tractable to study. To address fundamental questions relating to the fitness of members in a community we have developed a model competitive system using two soil bacteria: Bacillus subtilis and Streptomyces sp. Mg1 (S. Mg1).

Publications:

  • Stubbendieck RM, Straight PD. 2016. Multifacted Interfaces of Bacterial Competition. J Bacteriol In press. (Available at: http://jb.asm.org/content/early/2016/05/24/JB.00275-16)
  • Stubbendieck RM, Straight PD. 2015. Escape from Lethal Bacterial Competition through Coupled Activation of Antibiotic Resistance and a Mobilized Subpopulation. PLoS Genet 11:e1005722. http://dx.doi.org/10.1371/journal.pgen.1005722.
  • Stubbendieck RM, Zera AJ, Hebets EA. No evidence for a relationship between hemolymph ecdysteroid levels and female reproductive behavior in Schizocosa wolf spiders. Journal of Arachnology, 41(3):349-355. 2013.

Platform Presentations and Awards:

  • Student Research Week. Texas A&M University. College Station, TX. March 2016. Crisis Control: Adaptation to Microbial Competition.
  • 24th Annual Biochemistry and Biophysics Research Competition. Texas A&M University. College Station, TX. February 2016. Escape from Lethal Bacterial Competition through Coupled Activation of Antibiotic Resistance and a Mobilized Subpopulation. (1st Place Award)
  • 1st Annual Genetics Graduate Student Research Competition. Texas A&M University, College Station TX. February 2016. Escape from Lethal Bacterial Competition through Coupled Activation of Antibiotic Resistance and a Mobilized Subpopulation. (1st Place Award)
  • Genetics Graduate Student Seminar Series. Texas A&M University, College Station, TX. November 2015. Escape from Lethal Bacterial Competition through Coupled Activation of Antibiotic Resistance and a Mobilized Subpopulation
  • Genetics Graduate Student Seminar Series. Texas A&M University, College Station, TX. October 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • Biochemistry Graduate Student Seminar Series. Texas A&M University, College Station, TX. February 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • 5th Annual A. I. Scott Medal Sympoium for Excellence in Biological Chemistry. Department of Chemistry, College Station, TX.  November 2013.  Lysis and degradation of Bacillus subtilis in competition with Streptomyces sp. Mg1

Poster Presentations and Awards:

  • 5th American Society for Microbiology Conference on Prokaryotic Cell Biology and Development. Washington, D.C. May 2015. Lysis of Bacillus subtilis in Competition with Streptomyces sp. Mg1
  • 5th John Innes-Rudjer Boškovic summer school in Applied Molecular Microbiology on "Microbial Specialised Metabolites: Origins and Applications". Dubrovnik, Croatia. September 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • 10th Gordon Research Conference on Microbial Stress Response. Mount Holyoke College, South Hadley, MA. July 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • Genetics Graduate Student Association 6th Annual Mini-Symposium. Texas A&M University, College Station, TX. April 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • Genetics Graduate Program Graduate Student Research Competition 2013. Texas A&M University, College Station, TX. February 2014. Chemical Genetic Approach to Understanding Lysis and Degradation of Bacillus subtilis by Streptomyces sp. Mg1.
  • Genetics Graduate Student Association 5th Annual Mini-Symposium. Texas A&M University, College Station, TX. April 2013. Identifying Molecules Responsible for Competitive Lysis and Degradation of Bacillus subtilis.
  • Genetics Graduate Program Graduate Student Research Competition 2013. Texas A&M University, College Station, TX. February 2013. Identifying Molecules Responsible for Competitive Lysis and Degradation of Bacillus subtilis.

Travel Awards:

  • Biochemistry Graduate Student Association Travel Award Fall 2014
  • Genetics Graduate Student Association Travel Award 2014

Memberships and Activities:

  • American Society for Microbiology. Member 2014-Present.
  • Biochemistry Graduate Student Association. Member 2012-Present.
  • Genetics Graduate Student Association. President 2013-2014. Treasurer 2012-2013. Member 2011-Present.