Beyond dissecting frogs: Baldwin High School students study cellular transformation
As Baldwin High School life sciences teacher Andrew Ising passed out laboratory utensils to his 8 a.m. biology class this past week, he shared a word on their instructions.
“When they send you these labs, they assume you don’t know how to use inoculation loops,” the teacher said.
“We are a college biology lab,” said junior Riese Wismer with mock outrage.
That was true, Ising said, but added that he — unlike the high school students in his class — wasn’t introduced to the tool until he was taking 400-level biology courses at Kansas State University.
The loops were a tool the students used last week during an exercise to genetically transform E. coli bacteria. Ising, who started teaching at Baldwin High School this year, said the experiment duplicated techniques first developed in research labs about a quarter century ago. It may be a long way from the dissection of frogs that older generations remember from biology class, but, as junior Wismer noted, the class is college biology.
In the more than two decades since the technology and technique were developed, they have filtered down to become a standard exercise in Advanced Placement high school biology classes, and Ising introduced it this year at Baldwin High School. He was able to add it to his two college biology sections at Baldwin High School thanks to a $1,400 grant he received last fall from the Baldwin Education Foundation.
The money allowed the high school to purchase a microcentrifuge, incubator and lab kits used in the exercise, Ising said. The exercise involves placing a plasmid of DNA taken from deep-sea fish into a colony of E. coli bacteria.
The bacteria is best known as a result of the several deadly E. coli food contamination outbreaks in recent decades. Ising said those were caused by a few strains of the bacteria. Others are harmless or even beneficial, such as those that live in human intestines, he said. The E. coli used in the exercise is a domesticated strain bred for lab use.
“These are ‘safe’ to the point that you could, but probably shouldn’t — just to be safe — drink a flask full of the bacterial cells with no noticeable change to your health,” Ising said.
Nonetheless, the students followed established lab-safety precautions that treated all bacteria as dangerous. The students were careful to disinfect all work areas with bleach and sterilize all tools used.
They wore gloves and goggles as they worked through the 16-step process to introduce the foreign DNA to the E. coli. What makes the DNA more interesting is that it is bioluminescent and will turn the modified bacteria blue and glow in the dark.
The seven students in the class had 50 minutes to work through the exercise that ended with them placing petri dishes in an incubator for 24 hours, where the modified bacteria should thrive and multiply. The intricate work required the students to make the bacteria “competent” to accept the introduced plasmid by creating small holes in the bacterial cell walls. That’s done by suspending the E. coli in a calcium chloride solution and alternately icing and heating the bacteria and plasmid.
Wismer and her lab partners, juniors Hannah Spriggs and Paige Leslie, viewed the work as preparation for the careers they plan to have in science. Wismer plans to study biomedical engineering, while Spriggs and Leslie want to be veterinarians.
Ising’s other college biology section has two students who want to study medicine and another planning to major in pharmacy, Ising said, but he predicts even those students not planning science careers will find the class useful.
“I would be surprised if all the students didn’t benefit from these skills,” Ising said.
Any students going on to study microbiology in college will almost certainly find themselves working again with bacteria modified with bioluminescent DNA or proteins. Ising said bioluminescent DNA or proteins are used as research tags when they are fused with another protein of interest and then spliced into cells. The glow allows researchers to trace the protein they are interested in and study its effects on cells.
As she cleaned up at the end of the lab with the team’s petri dishes warming in the incubator, Spriggs said that completing the process made her feel like a scientist. She was confident her team would be successful when they removed the samples the next morning.
“I think we did well,” she said. “I hope it glows.”