Tag: spectrophotometer


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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Skills Testing

by gwilson on Nov.25, 2009, under A Day in the Life...

Flaming your loop

Flaming your loop

Today the Microbiology students took their lab skills test.  I give them two opportunities to show their proficiency in streaking plates, performing aseptic transfers, pipetting, using a spectrophotometer, reading biochemical test results and indentifying bacteria, describing colonies, doing Gram stains, finding and describing cells under the microscope, cleaning up bacterial spills, designing experiments, and writing Materials & Methods.  Those who did not perform up to expectations will have another chance in about a week.  After all, my goal is not to see what they’ve learned by Thanksgiving – it is to insure they have the skills mastered by the time the course is completed.  What is more important than when.

None of these skills were taught independently in this course.  All were learned as students did research projects, using a “just-in-time” approach to teaching.  Aseptic technique was taught when we needed to inoculate tubes and plates for purification and identification.  Smears and staining were taught when we needed to determine which biochemical tests to inoculate and rapid ID panels to use.  Spectroscopy and dilution methods and pipetting were taught when we needed to conduct pour plate counts to follow survival of cells following exposure to radiation.  In every instance, there was a reason and connectedness between what we were doing and a clear goal we were trying to achieve.  Techniques were not islands unto themselves but instead means used to discover the truth at the end of the journey.

We believe students learn better, retain better, and are more engaged in their work when this approach is taken.  That is why the BIMS program is skills driven, research-rich, and product-oriented.

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New Equipment

by gwilson on Aug.29, 2009, under A Day in the Life...

C-0036-HKThis summer the Biomedical Science program was able to purchase several new pieces of equipment to support teaching of genetics and molecular biology courses.  Most notable, our aging Bio-Rad MyCycler thermocycler has a new partner-in-crime, a Bio-Rad real-time PCR thermocycler that will add capability for teaching and research.  Additionally, a new Bio Tek Ultra Microplate spectrophotometer and Nanodrop microvolume analyzer will help in analysis of samples.  We have two additional tissue culture hoods on order which will replace one old biological safety cabinet and add capacity for additional student work.  Chemistry was also able to purchase a gel documentation system.  Add to those the Hermle centrifuge obtained in May and it is clear the capabilities of our faculty and students has been significantly upgraded over the past six months.

So how was this done during trying economic times by a university that is not wealthy?  Several contributing factors made this possible.  First, budget decisions are based on assessment results.  BIMS faculty have been careful to document the weaknesses of students through the years and make a strong case for expenditures to improve teaching and learning.  They also have demonstrated how the purchases have led to gains in student performance, both through gains in Major Field Test scores and also in student involvement in research opportunities.  The research-rich curriculum of BIMS courses helps justify funding through departmental budget allocations and capital funds that have to be spent on capital items.  Second, the curricular innovation provided by the BIMS major supports President Russell’s Vision 2023 call for enhanced research for students and faculty, relevant programs, and attention to graduating students competitive for jobs of the next 20 years.  Also, funds provided by generous donors to the Imagine – Shaping the Future Capital Campaign have helped supply some of the funding not provided by other means.  When you are doing exciting things aligned with the vision and goals, and your efforts support the strategic plan, appreciative administrations are more likely to reward you!

Who wins?  McMurry’s students!  Their success is why we are here!

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