Tham khảo tài liệu 'biosensors for health environment and biosecurity part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 482 Biosensors for Health Environment and Biosecurity Summary of advantages and disadvantages Advantages and Disadvantages of the D-luciferin Utilizing Luciferase Proteins Advantages Disadvantages High sensitivity and low signal-to-noise ratio Quantitative correlation between signal strength and cell numbers Low background in animal tissues Variations of firefly luciferase stabilized and red-shifted and click beetle luciferases red and green are available Different colors allow multi-component monitoring Requires exogenous luciferin addition Fast consumption of luciferin can lead to unstable signal ATP and oxygen dependent Currently not practical for large animal models Table 2. Advantages and Disadvantages of Using D-luciferin Utilizing Luciferase Proteins in the Mammalian Cellular Environment Luciferase proteins that utilize coelenterazine as an exogenous substrate While the D-luciferin utilizing Luc system may be the most popular for mammalian imaging experiments it is the coelenterazine utilizing luciferase proteins that are the most widely occurring. In nature there are examples of these types of luciferase proteins in cnidarians copepods chaetognaths ctenophores decapod shrimps mysid shrimps radiolarians and some fish taxa as well Greer Szalay 2002 . The coelenterazine substrate has the chemical structure of 2- p-hydroxybenzyl -6- p-hydroxyphenyl -8-benzylimidazo- 1 2-a pyrazin-3- 7H -one Bhaumik Gambhir 2002 and under its native function is bound to an associated protein to prevent availability to the luciferase. The strength of this bond is dependent on changes in calcium dynamics within the host cell with increases leading to the detachment and subsequent availability of the substrate to participate in the bioluminescent reaction Anderson et al. 1974 . This system has been adapted however so that when the luciferase protein is expressed in a host cell the coelenterazine substrate can be supplied exogenously triggering the production of light .
