There has been use of a broad range of methods for controlling bacterial growth. The specific method employed is based on the kind of bacteria, as well as the nature of the material for which the user is seeking. Therefore, in order to control bacteria that form endospore needs techniques varied from the ones utilized for other cells, while surgical equipment sterilization would need treatments that are different from the ones employed in prevention of infection of an injury. Ultraviolet light, denoted as UV, can be termed as an electromagnetic radiation, which has a wavelength ranging from 100 to 300 nm. It is antimicrobial since it destroys molecules of DNA, as well as the genetic information (Alyssa, 2004).
In an experiment, the UV light was examined on how it could be employed in generation of Serratia marcescens mutant strain having modified pigmentation or show other novel features in culture plates with and without lids. The growth of the bacteria was compared on the plates that were covered, as well as those that were not covered. The plates were then exposed to UV light. The bacteria were then analyzed after growth for 24 hours. Growth was compared between the covered and the uncovered plates. The main objective of this experiment was to determine how short term exposure of UV light affects a bacterium. In another experiment, the hypothesis that UV light intensity does not affect the mutation rate in Serratia marcescens was tested (Natasha, 2001).
Following the examination of the bacteria after 24 hours of growth, it was evident that the background, which was the Petri dishes that did not go through exposure to the UV light, had a number of normal bacteria. Nevertheless, the bacteria that did not go through exposure to UV light exhibited little or absence of normal colonies or the colonies were mutated.
Following the comparison of growth between the covered and uncovered Petri dishes after exposure to the UV light, it can be stated that the UV light significantly decreased the colonies number that were formed on the plates. Just the bacterial colonies, which were subjected to the UV light at a shorter distance, gave credible results. The only enough colonies number that formed was on the Petri dishes that were not subjected to the UV light. Moreover, the number of colonies, which mutated was almost none. This could have been contributed by that the fact that the bacteria were subjected to the UV light for long, hence killing the bacteria. On the basis of the experiment, the hypothesis that UV light intensity affects the mutation rate in Serratia marcescens was accepted since the UV light intensity did not affect the rate of mutation.
Exposure of colonies of S. marcescens to UV radiation leads to mutations of DNA. The energy of radiation is taken in by bacteria, and when there is a long exposure to UV light, thymine nitrogenous bases next to one another in strands of DNA usually form cyclobutane rings referred to as thymine dimers. When multiplying and replicating DNA, the enzymes that are responsible for the process of replication normally adhere to a different base instead of the thymine bases, as well as a mutation usually arise. The manner in which UV light causes effects on the DNA, and accordingly synthesis of protein is altogether dependent upon the position of mutations (Bank, John, Schmehl, & Dratch, 1990).
Reference List
Alyssa, E. B. (2004). What Are the Effects of Ultraviolet Light on Bacteria Mortality. Retrieved April 7, 2014, from www.usc.edu/CSSF/History//J1303.pdf
Bank, H. L., John, J., Schmehl, M. K., & Dratch, R. J. (1990). Bactericidal effectiveness of modulated UV light. Applied and environmental microbiology, 56(12), 3888-3889.
Natasha, L. H. (2001). Ultraviolet Light vs. Living Organisms. Retrieved April 7, 2014, from www.usc.edu/CSSF/History//S1209.pdf
