Greeting!

Welcome to our micro- and nano- dynamic research website.

We are a multidisciplinary multicultural group headed by Professor Kenneth Foster, a physicist who uses both experimental and theoretical approaches to solve important biological questions. Professor Jureepan Saranak supplements the team with the biomedical science background.

Our overall research goals are to understand at the cellular and molecular levels each of the biological signal processing components in the chain from the sensory inputs from external and internal sources, the intracellular signal processing network, and the varied output responses. We use model cell systems from four major biological Kingdoms:

 

• The Green Alga, Chlamydomonas reinhardtii
• The Fungal zoospores of Allomyces reticulatus
• The Stramenopiles, Mallomonas and Fucus sperm.
• The Euglenoids,Peranema

J. Vidyadharan and K. Foster We particularly study the visual system --- starting from the architecture of its light capturing structure, a dielectric antenna or eye. At the cellular level, the nonlinear ciliary responses that enable the cell to use its eye to track the direction of light are being analyzed. At the intermolecular level, we are employing systems analysis to describe the network of sensory signals within a single cell. Some of these signals come from light receptors at the eye and are used to steer the cell with its cilia. At the molecular level, we are studying how biological light sensor molecules (rhodopsins) work. Specifically, the mechanism of activation of the rhodopsin and other G-protein-activating receptors has been sought. With the conservation of nature, hundreds of different receptors in human would appear to be in the same superfamily, first evolved 3.5 billion years ago. In addition, we wish to understand the ubiquitous pathways by which light can control gene expression.

For the biological output system, we record and analyze different levels of responses from cell population and single cell phototaxis (swimming direction of the cells with respect to the light path), single cell swimming pattern,electrical field and current of cell population, 2-D and 3-D ciliary motion.

One of our projects aims at understanding the beating and control mechanisms of a cilium --- a slender cylindrical appendage of eukaryotic cells specialized for propulsion, moving fluids, measuring fluid flow or modified as a sensor. The core structure of the cilium, known as the axoneme, consists of nine microtubule doublets surrounding a central pair of microtubules. Taking into account the hydrodynamic forces along the cilia, we develop both experimental and theoretical techniques to identify mechanisms controlling the ciliary functions.