Research seeks end to parasite suction

John Pekcan / Daily Titan

John Pekcan / Daily Titan

Research surrounding the insights to the mechanisms of host attachment and colonization by the widespread parasite Giardia intestinalis was presented by Scott Dawson, Ph.D., a UC Davis professor, on Wednesday.

Dawson’s research on parasitic protists is more commonly known as Giardia, a single-celled organism and waterborne pathogen that lives in most water supplies.

Parasites live on or in a host organism, causing harm to the host.

Dawson gained an interest in protists while completing his doctoral dissertation.

It was during this time that he came across protists in an anoxic environment, an environment absent of oxygen.

His ultimate interest resides in how and why these eight Giardia flagella are uniquely specified in their function.

Flagella are hairlike structures within a cell that help the cell travel.

At the event, sponsored by the Biology Department and held in McCarthy Hall, Dawson explained how Giardia intestinalis are the most common causes of protozoan intestinal infections in the world, therefore affecting humans and animals by attaching to the small intestine in the form of a suction cup, and residing there for as long as a few months.

There are about 2.5 million cases per year in the U.S., and one billion people are affected worldwide by microscopic Giardia.

A person infected with Giardia will loose an average of about 20 pounds and experience frequent symptoms of diarrhea.

“It colonizes itself, and we don’t know why it makes you sick,” said Dawson. “If it attaches to your body, it forms a cyst again, and that is what shatters the environment.”

He added that he is studying the mechanism of how that suction cup works on a molecular and cellular level to better understand how to develop drugs for treatment.

Dawson explained that the cure for Giardia is an antibiotic called Flagyl. Although similar to other antibiotics, it kills good microbes along with the bad.

The problem with a lot of parasitic drugs is the biology of the organism is similar to human biology said Dawson.

“It’s in some ways harder to solve antibiotics that are specific to those organisms,” Dawson said.

Bradley Tapia, a biology major, said learning about how they hypothesized made for a well structured presentation and he took away more than he knew coming into it.

Dawson’s current research on the suction cup, or vexel disc of the Giardia, is more commonly referred to as the cytoskeleton.

This cytoskeleton is seen most frequently through experiments with field mice.

This allows Dawson and his lab to view what the vexel disc looks like and investigate the behavior of the Giardia in one of the small intestines.

Michael Medinez, a biology grad student, said it was good to see the research being done on Giardia.

“(Dawson) was saying there is not much being done at the current plant, and there’s maybe 10 labs in the U.S., so it was cool to see his presentation here today,” said Medinez.

He added that overall he thought the presentation was interesting.

The experiments involved in investigating Giardia’s every move is complex and requires Dawson and his lab to test the organism using a tool called optical imaging.

This imaging provides bioluminescent, a glow in the dark feature to view the Giardia in the host.

“Our lab employs multiphasic approaches to define the primary structural elements of the ventral disc at high resolution, to identify and analyze disc protein function, and to quantify attachment dynamics and test attachment hypotheses using high resolution live imaging,” Dawson said.

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