Research Paper Biol 141L

Submitted By niihar7
Words: 3320
Pages: 14

To what extent does the varying light intensities affect the ability of C. Elegans to move towards a food source?

Abstract: As model organisms, C. elegans will be used to check the effect of light intensities on the movement of the worms towards their food source. To further enhance the previous research conducted on similar topics, we decided to narrow our scope of experiment so as to not only focus on the light intensities, but also the attraction by the food source. The light conditions created in this experiment are high light intensity, dull light intensity, and normal light intensity; the bacteria used in this experiment as food source are E.coli OP50 and Rhizobium Leguminosar. We hypothesized that most number of worms will move towards the bacteria under dull and normal light intensities, and most number of worms will move away from the bacteria under the high light intensity. Also, we predicted that E. coli OP50 would be a better food source for the worms as they are already accustomed to the bacteria. In all, we can further use C. elegans in similar experiments to gain a better understanding of the movement and growth in worms, that will enable us to approach our current ideas and theories from a new perspective.

Introduction: Caenorhabditis elegans, commonly referred to as C. Elegans, are transparent nematode worms, a species of roundworm usually found in terrain. C. Elegans have only recently become a popular model organism as biological experiments performed on these worms tend to be high in external validity_. In addition, it’s prolific life cycle, ease of maintenance, and a distinctive genome are a few features that have contributed to it’s success in numerous fields of scientific research_. Several experiments have indicated that C. Elegans generally lack photo taxis_ simply because these worms do not possess light sensing organs such as the eyes and inhabit the darker regions of the terrain. However, a study disputed the claim that C. Elegans are light insensitive_ by following this line of thought, and questioning the presence of organs that elicit responses to the dark environment such that it acts as a negative trigger so as to lead them back to darker environments when subjected to an external light source.
Even though a fair amount of research has already been conducted on the effects of light intensity on C. Elegans, there is scope for extending the existing knowledge in the research of the movement of C. Elegans towards a food source in relation to varying light intensities and for testing previously conducted research experiments. In actuality, multiple factors determine a particular characteristic displayed by C. Elegans. Inferring causation can be difficult; therefore it is imperative to design the experiment in a way that singles out factors that mostly likely influence the overall outcome of an experiment.
Moreover, studies also inform us about a group of ciliary sensory neurons that act as photoreceptor cells for moderating photo taxis. These discoveries suggest a novel sensory organ in C. Elegans and implies that organisms living in the dark are not necessarily light insensitive, despite lacking light sensing organs_. Not only will this experiment delve into the response of C. Elegans to varying light intensities as mentioned above, but it will also deal with their responses to different food sources: namely OP50 and Rhizobium Leguminous. Both, the light intensity as well as the bacteria was varied simultaneously. Since there are significant differences between the Mutant type C. Elegans and the wild types, hence it is essential to take the two different types of C. Elegans as a part of the experiment. This will enable us compare the two types in order to gain a better understanding of the differences in the way in which they react to different light intensities and different food sources.

Methods: The types of worms used in this experiment were Wild type C. Elegans and the…