Miami University

Instrumentation Laboratory Project Page

Project: Temperature Gradient & Light Assembly

Department: Microbiology

Primary Investigator: Dr. Rachel Morgan-Kiss

Purpose: One of the major goals of the research program in the Morgan-Kiss laboratory is to understand of life is adapted to extreme conditions. A particularly stressful condition for life is low temperatures. Our laboratory has a number of projects that focus on microbial life living in Antarctic environments. We work on both natural communities of microorganisms as well as isolated species. The Instrumentation laboratory built two kinds of thermal gradients for us to study physiological responses in our Antarctic organisms. One of the gradient block systems accommodates small (less than 2 milliliters) tubes which are used for measuring the effect of temperature on enzyme activity. We are currently testing temperature effects on the enzyme RubisCO, which is the key enzyme responsible for fixing carbon dioxide into sugar in all photosynthetic lifeforms. The second gradient block system (pictured below) accommodates larger tubes and also is modified to provide a light source. This block can be used for testing the effect of temperature on the growth of microalgal cultures. We also use the larger block to grow microalgae isolated from Antarctica under a temperature gradient and then measure the thermal effects on their ability to capture light energy using additional equipment in our laboratory. The combination of these two thermal gradient blocks allows us to rapidly obtain a broad view of the physiological effects of temperature on many photosynthetic processes in a large range of Antarctic and non-polar algal species.

IL Comment: IL took the user's concept and input, the IL designed and built the system to meet the PI's research needs. The system requires the use of a water bath for cooling. The temperature gradient is adjustable on both the low and high ends. On initial system, the high end was measured in the heater block, in the second version, the thermocouple was moved onto the gradient block for more precise temperature control. The second system also can apply light to the bottom of the sample tubes and the light brightness can be adjusted as required.

Cost to researcher:  1st system's cost: $580.18     2nd system's cost: $823.36 (Neither cost incorporates the cost of the water bath required.)

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