BIMS

Tag: gram positive cocci

I Love Technology

by gwilson on Apr.12, 2013, under A Day in the Life...

DSCN4455In Micro, we teach techniques through student projects. Early in the semester we studied Gram negative rods from foods to learn the basics of aseptic technique, pipetting and viable counts via pour plates, staining, microscopy, selective media, bacterial testing and identification, etc.  Our most recent project needed to center on Gram positive cocci, so our four groups in lab chose where to do their sampling.  We stayed away from places dangerous bacteria might be easily encountered, and then we sampled like crazy to see what we might recover and identify.  Whether credit cards or cell phones or feet or fingertips, the groups all found Gram positive cocci and began their characterization.  The result was nearly 40 unique isolates for us to investigate.

Identifying bacteria can be a long, laborious and expensive process.  My students do some basic tests to get a feel for how the process is done.  But we never go test-by-test, day-by-day to definitively identify our isolates.  Instead, we use BD-BBL Crystal (R) Rapid ID panels.  Students inoculate the panels with their culture, snap them closed, and then toss them in the incubator overnight.  For Gram positive cocci, we use the GP panels, good for a wide range of cocci and bacilli.  Each panel is designed to give answers for 30 separate tests useful for identification.  We have manual readers that students can use to interpret test results (based on color charts provided).  But when we renovated labs a few years back we built into the budget an automated panel reader that interfaces with a computer and provides two important functions:  reading all 30 tests and interpreting their results to generate an identification.  It was well worth the expense.

Today I came in and read results for over 1000 biochemical tests and identified over 30 bacteria in less than half an hour.  When my students come in Tuesday, they will be able to add that information to their lab reports (research posters) and analyze that information to complete their posters.  Sure beats having to make the media for those tests and wash the sterilized remnants later!

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Last Week in BIMS

by gwilson on Feb.27, 2011, under Projects

We had another BUSY week in Biomedical Science courses.

  • Freshman-level BIMS 1300 Intro to Scientific Research students learned how to use their Tablet PCs to gather data from a “Brain Test” all students took (determined analytical vs. creative, auditory vs. visual) and calculate standard error of the mean, as well as linear regression analysis of data sets.  In the lab, students finished up their observation projects that will be presented in the coming week.
  • The new microbiology course for allied health majors, BIOL 3403 Fundamentals of Microbiology participated in a webinar hosted by McMurry alumna Mary Lynn Smith (’83) on biofilms in healthcare.  This was an example of how experts and professionals a thousand miles away can contribute to our students’ education.
  • In BIOL 3410 Microbiology, students finished the identification of Gram positive bacteria found in their cars.  They are working on research posters describing their studies and will turn those in next week.  In short, they took samples from the HVAC and interior surfaces of their cars, isolated and purified bacteria, and pursued identifications of the Gram positive cocci found using conventional tests and the BD-BBL Crystal(TM) Rapid ID panels.  Follow-up tests included testing for oxacillin-resistance, an indicator of community-borne MRSA.
  • In BIMS 4391 Advanced Microbiology, students moved forward in their development of antibiotic-producing bacteria.  They completed the identification of their endospore-formers using microscopy, conventional tests, and BD-BBL Crystal(TM) Rapid ID panels.  Then, they grew their bacterium in batch culture, removed the cells and spores by centrifugation and filtration, and challenged six microbes (two Gram negative rods, two Gram positive cocci, two yeasts) with the filtrate in disk diffusion tests.  Those antibiotic producers with the most promise will be grown in our new benchtop fermenters and their products characterized by chemical, physical, and physiological means to learn more.
  • In our BIMS 4201 Capstone Research class, senior students began cultivating the Saccharomyces cerevisiae strain genetically-modified with human estrogen receptor as a prelude to the use of the YES assay for monitoring the presence of estrogen-mimics in the environment.

All this may sound way beyond the  reach of normal college students in normal college classes.  Not so!  We find that students are more engaged in learning techniques and information when there’s a reason or goal – a pot of gold at the end of the rainbow!  It is at the heart of the skills-laden, research-rich approach taken in teaching BIMS courses.

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