Tag: Bt


by gwilson on Sep.05, 2013, under Projects

DSCN2675Drs. Benoit and Wilson have long had a love affair with Bacillus thuringiensis (Bt) spores and their study.  Their many papers on the subject have often centered on a germination assay that follows the conversion of dormant and resistant spores back to vegetative growth.  The assay is based on watching a change in the optical density (absorbance) of spores using a spectrophotometer.  It is fast and easy and dependable.  At least it was until about 12 years ago when that assay, for some reason, stopped working.

The first indication something was wrong came in the form of an email from a researcher in New Zealand in the fall of 2001.  The graduate student was studying Bt germination and ran into difficulty replicating the results Wilson and Benoit had reported.  The email simply asked Dr. Wilson whether there were any special tricks involved in the assay.  Since neither Wilson or Benoit was involved in research due to administrative responsibilities at the time and had not experienced similar problems, they had no advice to offer.

Fast forward a few years to the creation of the BIMS program and a new graduation requirement that every student must participate in capstone research, an Honors project, or an internship.   The department needed research ideas, and Benoit and Wilson resurrected the germination assay as a means to engage students in studying new aspects of spores physiology.  The number of unique projects this system would provide for future students was enormous.   But the assay failed to work.  Even with new facilities and new resources to support research, several student projects failed to recreate results from earlier papers.  Nothing in the literature and no one in the field had an answer.

This summer, Honors student Heather Rawls became the most recent student to attempt the assay.   Through the summer she tried differences in media, growth temperature, ways of collecting and processing spores, water quality being used, activation techniques, a variety of germinants, and at least five different spectrophotometers with no predictability or consistency in the results.  If anything, fewer and fewer spores were germinating with each attempt.

In August, Heather and Dr. Wilson had a research pow wow and developed an alternate project for her Honors thesis.  Time was running out to complete her research before starting the writing, and moving to something with a higher probability for success was needed.  But Heather wasn’t ready to give up that easily.  At an impromptu meeting a couple of weeks ago, a new thought emerged when it seemed every variable possible already had been tested.  Glassware!  In their graduate programs and during their prior research using the assay, Benoit and Wilson always collected the spores in glass containers and the germinants and all other chemicals used had been stored in glass containers.  In our growing emphasis on research, McMurry had improved the funding of science programs so much that the use of disposable plastics was now the norm.  Maybe the plastic centrifuge tubes used to collect spores and store germinants were coated with something inhibiting spore germination?  Maybe some chemical was leaching out of the plastic?

Over the last two weeks, Heather switched to glassware for collecting spores and making reagents.  Her results were dramatically different.  We now are certain plasticware has an inhibitory effect on germination.  A decade of frustration was caused by our affluence and the use of disposable labware rather than old-school glass.

With a working assay, Heather will turn back to the project she intended to complete this summer looking at the germination of a variety of genetically-engineered and wildtype strains of Bacilli.  Another Honors student just beginning her work will investigate what the mystery chemical from the plastics might be and how it inhibits germination, or the range of spore-forming species affected.  One mystery is solved, more are uncovered…

BIMS Honors students prove to us on a daily basis that they are among the best thinkers and hardest workers on campus.  This commitment to uncovering the truth is what will drive them to become leaders in biomedical science and healthcare provision in the future.

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Honors Research

by gwilson on Apr.01, 2013, under Projects

CWB ChinaRock croppedRecently, three BIMS majors found out they will receive Bloomer and Beasley Research Fellowships for the coming year.  All three are students of Dr. Gary Wilson and will be pursuing different projects investigating Bacillus thuringiensis spore properties as they pursue Honors research and write their Honors theses in the next year.

The Charles and Lisa Bloomer Research Fellowship is awarded to support research of promising students in the School of Natural and Computational Science (SNCS).  This initiative of the Science and Math Advisory Board (SMAB) provides a research stipend for students as they work closely with McMurry faculty on a research project.  Dr. Bloomer is a successful oral surgeon in Abilene who has generously and regularly supported the sciences at his alma mater.  The biennial picnic the Bloomers host for SMAB members and SNCS faculty is a popular event building relationships and communicating the vision each holds for McMurry’s science future.  The Beasley Research Fellowship is a new program supporting student research in the biological sciences.  McMurry’s science alumni are spearheading an effort to create an endowment in memory of Dr. Clark Beasley, Distinguished Professor Emeritus from the Department of Biology who died this past summer.  This represents the first year this fellowship has been awarded.

Recipients of this year’s awards are Heather Rawls, Miranda Nguyen, and Nicole McGunegle.  Their projects will study wild type and genetically-engineered strains of Bacillus thuringiensis (Bt) and Bacillus cereus (Bc) grown in rich and poor media.  Bt is a spore-former that produces an insecticidal toxin at the time of sporulation.  Bc is a commonly encountered and well-studied spore-former closely related to Bt but generally harmless.  The genetically-engineered strains include  Bt strains that do not form crystals and Bc strains that have been engineered to produce Bt crystals.  One project will look at how the presence or absence of the crystal in rich and poor media influences spore and crystal size and toxicity.  A second project will look at how growth conditions impact spore dormancy and the process of activation and germination.  It is possible an undiscovered variation of quorum sensing might be involved.  The third project will explore UV and chemical resistance of wild type and genetically-engineered strains produced in rich and poor media.  All projects fit the criteria for BIMS research:  a complete project doable in a short time frame, certain discovery no matter the experimental outcome, publishable work.

Stay tuned for updates on how this work is progressing!

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Research Directions 2012

by gwilson on Aug.18, 2011, under Projects

Every year the BIMS faculty sits down and discusses what research they might pursue for the sake of teaching and capstone projects.  With the start of school only a week away, we have narrowed our focus to a couple of very promising avenues for student research.  We thought you might like to know what’s made it to the top of our list for possible projects…

Crystal panel colors1. Bioactive compounds in the environment.  Last year we began work to gear up use of the yeast estrogen screening (YES) assay to test soils and waters for the presence of estrogen-mimic compounds.  Such compounds have been implicated in estrogen-fueled cancers, early onset of puberty, and other such health issues.  Our early discussions this year have included involvement of Biochemistry in the use of the screen for testing area ground water and soils while Biology capstone students (BIMS 4201) may pursue use of biofermenters to produce mixed populations of microbes capable of destroying the chemicals.  So, using our resources to identify the problem and find solutions.  I like that!

DSCN37852. Spore physiology and ecology.  During my doctoral research, I made some discoveries that have gone unreported and have not been pursued since.  My work was on Bacillus thuringiensis (Bt), a  bacterium of economic importance because of the insecticidal crystal protein produced when it forms spores.  Unlike the rest of the Bt world at the time, my interest was not in the crystal but in the biology of the spore.  A part of that work involved studying, essentially, how diet influenced spore properties.  I found those spores created in high sugar environments were larger and more resistant to heat, UV, and harsh chemicals, and germinated differently than did spores created in low sugar environments.  I am teaching an Advanced Microbiology course (BIMS 4491) this fall where the students will resume the research with our goal to present results at the Texas Branch ASM meetings in March and to publish our results before the end of the year.  Students leaving McMurry with presentations and publications is a good thing! :)  Because the work is so expansive and offers so many opportunities for students to jump on-board, other students doing capstones may also find a piece of this puzzle they want to pursue.  This research teaches some great basic biology and microbiology and has tremendous biomedical importance – after all, Bt is the simulant used for research on anthrax!

Some might look at the type of work our students pursue at McMurry and determine that the research done here is not as “cutting edge” and sophisticated as that done at large universities.  Rightly so, and without apologies!  Our intent is not to invite undergraduates to wash dishes or “piddle around” on the fringes of our research, but to be the main contributors to our work – much as graduate students are at those large universities. Every student is exposed to research here, and they are integral to our progress – not footnotes to graduate students’ success!  Their work is the main course, the entree and not the parsley and onion soup.  The fact of the matter is there are always plenty of questions of interest and importance to be answered that are left behind as the juggernaut of big science crashes forward.  We will gladly fill in the blanks left behind as they rush onward.  Such questions provide a fertile ground for learning and discovery.  We are student-centered in our teaching and in our research.  BIMS at McMurry is simply “science done better”.

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