Measuring Single Cell Nitrogen Uptake with Infrared Microspectroscopy

Project PI: Walter Dodds & Justin Murdock, Biology, Kansas State University

Algae (red) growing on rock (white).
Algae (red) growing on rock (white).

Scientists know that some algae work hard for us by cleaning pollutants from wastewater. However, when humans overrun a system with nutrient pollution, algal blooms can harm aquatic life by blocking the sun, using up oxygen and producing toxins.
Justin Murdock studied algae attached to surfaces as a post-doctoral researcher working with Professor Walter K. Dodds at Kansas State University for the project, Understanding and Forecasting Ecological Change. Murdock, an aquatic ecologist now employed by the USDA, is particularly interested in algae and the potential benefits of these organisms, for example to maximize their natural processes in order to clean water.

Examination of algae biofilms revealed that many different species of algae (shown in red) of various shapes and sizes grow very close to one another as illustrated in the algae biofilm to the right. A major question given this proximity is whether the different algae compete with each other for light and nutrients.
Distribution of 15N isotope uptake in two adjacent algal cells.
Algae (red) growing on rock (white).

Answers to this question were provided by the first high resolution uptake of isotopically labeled nitrogen (15N) using Fourier Transform Infrared (FTIR) microspectroscopy.

These studies showed how single cells take in nitrogen and furthermore aid in the identification of sites of protein synthesis. Proteins are very important polymeric molecules that are essential for many living processes.Not only do these studies provide a new technique for probing synthetic pathways at the cellular level, but they will also aid scientists in gaining a better understanding of how algal cells function.

More information about this project was published in October 2010 and is available at

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