Saint Mary’s professors examine Alzheimer’s, counting methods
Kathryn Marshall | Monday, November 14, 2016
Two Saint Mary’s professors presented their research at a faculty colloquium Friday afternoon. Kathryn Haas, assistant professor of chemistry, shared her research on the link between Alzheimer’s, lead and copper in a talk titled “Transition Metals in Human Health and Disease.”
Haas said she enjoys chemistry because it can be used to solve important problems in the world, such as problems in human health. The role of transition metals in Alzheimer’s, which is the only disease in the top 10 causes of death in the United States that does not have a drug to prevent, cure or slow the disease, is particularly interesting, she said.
Transition metals are the metals in the middle of the periodic table, and the study of those metals and their essential, medicinal, and toxic roles are housed under the term inorganic chemistry, she said.
“The reason patients start losing memory and can’t see is because the brain degenerates, which is called a neurodegenerative disease, because the neurons are not communicating well,” Haas said. “The hallmark of Alzheimer’s is something called amyloid beta plaques. … The plaques are formed from proteins sticking together and forming a plaque around neurons that stops neurons from communication from one another.”
A previous study on monkeys, not performed by Haas, determined that environmentally relevant levels of toxic exposure to the metal lead at infancy leads to amyloid beta plaque, and thus Alzheimer’s, at a later age, Haas said.
Haas said zinc is an essential transition metal for the enzyme DNA Methytransferase (DNMT), which plays a role in regulation of the amyloid beta gene. When the gene is not regulated properly, plaques form in the brain. Haas, along with students Erin Reinhart, class of 2015, and Jennie Connell, class of 2016, determined lead, which is a sister transition metal to zinc, pushes zinc out and complicates the function of DNMT in turning the gene on and off.
Another interesting transition metal involved in neurotransmission is copper, Haas said.
“Copper is an essential metal important in the enzyme that synthesizes neurotransmitter production, is needed for ATP production and more. … The reason it is so cool is because it can transition between two oxidation states,” Haas said. “Copper not controlled properly can be dangerous, so proteins in body are designed to handle very, very essential yet potentially toxic cargo. I think it is interesting how proteins handle this cargo.”
To better understand copper, Haas studies the link between copper and neurotransmission, as when copper and alpha beta combine to form the alpha beta plaques causing Alzheimer’s. By working with researchers in Poland, Haas hopes to further understand the molecular basis of the interactions between the copper transporter protein known as Ctr1 and alpha beta.
Ranjan Rohatgi, assistant professor of mathematics, talked about his use of a counting method known as common rhetorics in his talk “Tiling Your Bathroom Floor: An Exercise in Counting.”
The idea for his research stems from a bathroom tiling project done in his own home, he said. He was intrigued when thinking about the different numbers of tile formations.
“The way mathematicians work, well, the way I work, is I’m pretty lazy. Instead of trying to solve these problems individually … I’m going to try and solve a whole bunch of problems at once, and actually I’m going to extend this to shape. One method to count the number of tilings for a whole variety of shapes is the goal,” Rohatgi said.
By following lozenges, and other shaped “tiles,” across specific regions, one can discover certain paths. Rohatgi can use the information about path numbers in calculating the determinate of a matrix, which provides the information necessary for a formula that can be used to determine the total number of paths and the number of different possible tile arrangements.
These formulas vary depending on the size and shape of a region, and also have applications in areas such as statistical physics, he said.
“I hope you learned two things,” Rohatgi said. “One, it can be easier to solve a whole bunch of problems at once than to try and solve them individually. Secondly, these problems that are literally putting shapes onto a bigger shape sound simple and looks simple don’t always have simple answer.”