Tag: cloning

Better Living Through Cloning

by gwilson on Nov.04, 2009, under Projects

Dr. D

Dr. D

This week, Dr. Heidi DiFrancesca’s Genetics students are testing foods for the presence of foreign DNA to determine whether they are “all natural” or have been genetically engineered.  Genetically-modified foods (GMFs) include those that contain corn or other plant products that have been improved through introduction of genes from other species.  Presence of such foreign genes in foodstuffs is detected using the same tools that allow federal agencies to see whether the plant’s genome has been modified genetically - molecular methods for cloning and DNA manipulation.

One frequently-encountered genetically-modified crop is corn, where the delta-endotoxin gene from Bacillus thuringiensis is introduced to the genome to enable the plant’s production of  the toxin to kill a variety of insects that can ruin the crop.  The toxin is harmless to people and other vertebrates – in fact, it is harmless to all but a small collection of insect pests.  We could eat the toxin by the handful without effect, but for those susceptible insects one bite means certain death.  You may recall the uproar in recent years over GMO/GMF (genetically-modified organisms/genetically-modified foods) and the European bans that resulted, or the threat to monarch butterfly populations some believed to be posed by fields of genetically-modified plants expressing the toxin.  The methods and materials to be used in Dr. D’s class were developed by industry to allow for screening of foods for presence of the delta-endotoxin gene.

Bt spores and bipyramidal crystals (source of the delta-endotoxin)

Bt spores and bipyramidal crystals (source of the delta-endotoxin)

Students will take common foodstuffs containing corn – perhaps corn chips, perhaps corn tortillas (this is Texas, after all!) – and extract the DNA contained within.  Then, using molecular probes for the delta-endotoxin gene sequence they will look for its presence in the DNA recovered.  More likely than not, someone’s corn-based product will have the target sequence because it has been genetically modified to improve yield.

Bottom line is our students are learning valuable skills that are used by industry professionals to address real-world concerns.  Not a bad week’s work for McMurry’s biomedical science students!

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Pooling Resources, Creating Opportunities

by gwilson on Mar.23, 2009, under A Day in the Life..., Projects, Students

endospore21This spring, Dr. Paul Pyenta has his Biochemistry II students diverging from the normal course of lab exercises.  In doing so, he is accomplishing three things:  teaching the techniques and knowledge of the course in a new and engaging way, giving his students exposure to how research is done, and keeping his personal involvement in research going.

About two years ago, a conversation between Pyenta and two Biology faculty exposed a problem he was equipped to tackle.  Drs Wilson and Benoit are microbiologists who study the spores of Bacillus thuringiensis.  Bt, as it is called, is mostly known for its production of a toxin that is selectively toxic for the larvae of several damaging insect pests.  During Wilson’s doctoral research, an interesting observation was made – the spores made in the soil seem better suited to survival in insects, and the spores made in insects seem better suited to survival in the soil.  This has spurred a desire to study the ecology of the organism more closely, and led Benoit to propose an experiment to follow the fate of individual spores through susceptible and non-susceptible insects.  But, with Bt spores so small, no convenient way was available to do the experiment.

Enter Dr. Pyenta.  In conversation, it was decided that spores and cells expressing green fluorescent protein (gfp) could be used to follow the spores through the insect. Only problem – no appropriate gfp-containing Bt strains existed.  All previous cloning of gfp in Bt was done to follow the presence of the crystal protein in nature, in genetically modified foods and the like.  Their discussion led to a proposal - Pyenta proposed that his lab could clone the gfp gene into Bt so that a visible marker was present to detect the fate of spores.

The cloning work has been conducted for the past two years by undergraduate students doing independent research for Pyenta.  It has gone slowly, as many quirks make cloning into Bt not possible by use of traditional methods commonly used.  Progress made so far has moved the project to the point where students in his Biochem II lab are equipped to use the lessons learned to tackle the project this semester.  In doing this, students get to see how the skills and knowledge of their regular course can actually be put into action on a real research project. 

One of the frustrations science faculty face at small colleges is finding time to remain active in research.  Expecting similar productivity to that achieved when one was a member of a research team working full-time on a project funded by a national agency is foolishness.  Instead, faculty must find creative ways to keep their skills up, perform experiments in economical and efficient ways, and use available resources wisely.  Dr. Pyenta is accomplishing these things by teaching his course through involving students in his research (instead of relying on a bunch of unrelated and seemingly random canned exercises leading nowhere), by conducting the work within the parameters of his normal teaching load, and by pooling resources through collaboration with other faculty on a project of common interest.

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