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Current in vivo Models for Brain Disorders
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
Marta Guerra-Rebollo, Cristina Garrido
In the specific case of brain tumours, one of the most utilised techniques to visualise drug delivery into the tumour is using BLI. The firefly luciferase (FLuc) can be used as a reporter gene and d-luciferin as a substrate. FLuc catalyses d-luciferin oxidation in the presence of adenosine triphosphate (ATP) and coenzyme A (CoA) producing O2 and photons which can be detected in vivo. Recording of the emitted light by photodetectors, capable of linear response allows for real-time measurements [57, 58]. This technique is based on the stable expression of luciferase by the brain tumour cell line selected for the experiment. Once the cells are implanted into the mouse brain, d-luciferin could be injected intraperitoneally into the host mice, where it is distributed throughout the mouse body and crosses the BBB. The intensity of the emitted light correlates to the size of the tumour and allows comparisons of tumours size across different animals but also within the same animal in different time points (Fig. 13.1) [59].
In vivo Imaging as a Tool to Noninvasively Study Nanosystems
Published in Costas Demetzos, Stergios Pispas, Natassa Pippa, Drug Delivery Nanosystems, 2019
George Loudos, Maria Tina Rouchota
Optical imaging methods use tracers that emit optical photons to image specific targets, without using radiation. Optical imaging can be divided into fluorescence imaging (FLI) and bioluminescence imaging (BLI) [41]. Bioluminescence is a normal process in animals like firefly that express an enzyme called luciferase, as a result of photochemical reactions. In BLI cells of interest have to be engineered first in order to express luciferase and then induced in the small animal. Injection of luciferine results in its oxidization by luciferase, and light is produced 10–12 min. after luciferin injection. This light signal is detected by a charge-coupled device (CCD) camera, and planar intensity images are produced. BLI is a highly sensitive technique, and only a few cells can provide sufficient signal. On the other hand in FLI the optical signal comes from a fluorescent molecule that can be either endogenous (collagen, hemoglobin, etc.) or injected (green fluorescent protein and other optical contrast agents). An external light source is used to excite the fluorophore, and a CCD detects the lower-energy emission light. Additional imaging components are filters that select excitation and emission wavelengths.
Introduction to optical imaging
Published in Ahmad Fadzil Mohamad Hani, Dileep Kumar, Optical Imaging for Biomedical and Clinical Applications, 2017
Dileep Kumar, Ahmad Fadzil Mohamad Hani
Bioluminescence is the phenomenon of bio-organisms producing light by the enzymatic reaction of a luciferase enzyme with its substrate luciferin. This luciferase enzyme is obtained from a firefly, which is a natural source of luciferase and is widely used in bioluminescence process to measure molecular changes in tissues of small animals. Luciferin is injected into a small animal and passes through blood tissues including the brain and placenta causing emissions of light from the molecules of small animals. The emitted light reaches its peak after 10–12 min and loses its intensity slowly over 60 min [10]. This time frame taken to lose emitted light intensity is sufficient to capture microscopic images of these molecular tissues in small animals. There are many natural sources of luciferase enzyme from other organisms that produce light of different wavelengths possibly leading to different colors such as red, green, blue, etc. [10].
Assays and enumeration of bioaerosols-traditional approaches to modern practices
Published in Aerosol Science and Technology, 2020
Maria D. King, Ronald E. Lacey, Hyoungmook Pak, Andrew Fearing, Gabriela Ramos, Tatiana Baig, Brooke Smith, Alexandra Koustova
One of the potential methods to reduce processing time in bioaerosol analysis is the bioluminescence-based technique that detects the presence of adenosine triphosphate (ATP), the basic energy molecule present in all types of living organisms. The method uses the firefly enzyme luciferase to catalyze a reaction between its substrate D-luciferin and ATP, causing luciferin to emit photons in the 500 nm range (Karl 1980). Since the intensity of produced light is directly proportional to the ATP content (which is proportional to biomass), it is possible to quantify microbial biomass by measuring the ATP content using bioluminescence. The ATP method was used successfully for the rapid characterization of bioaerosol sampling devices when collecting bacterial aerosols in various environments (Seshadri et al. 2009; Park et al. 2014).
New approaches towards the discovery and evaluation of bioactive peptides from natural resources
Published in Critical Reviews in Environmental Science and Technology, 2020
Nam Joo Kang, Hyeon-Su Jin, Sung-Eun Lee, Hyun Jung Kim, Hong Koh, Dong-Woo Lee
To monitor the effect of chemical compounds on target pathway activity, a reporter frequently used for drug screening, the firefly luciferase (FLuc) reporter, is often employed (Xie et al., 2016). Reporter-based assays can be used to analyze gene expression and are highly sensitive, enabling accurate quantification of small changes in transcription. For instance, recently, the human H293-NF-κB-RE-luc2P reporter cell line was developed to identify anti-inflammatory bioactive compounds (Meijer, Vonk, Priebe, & Roelofsen, 2015). This system can be used to monitor a compound’s ability to inhibit TNF-α (Tumor Necrosis Factor-α)-induced NF-κB activity. The reporter line, derived from the human embryonic kidney cell line HEK293, contains NF-κB response elements five stably transfected upstream of the promoter of an optimized luciferase reporter gene (luc2P). Induction of the luc2P gene produces chemiluminescence when the substrate is added, and the amount of chemiluminescence generated is directly proportional to the changes in nuclear translocation of the NF-κB protein, and thus the assay can be used to measure inflammatory activity. The H293-NF-κB-RE-luc2P reporter cell line is a useful and sensitive tool for the rapid identification of BPs with anti-inflammatory activity.
Effects of water produced by oil segment on aquatic organisms after treatment using advanced oxidative processes
Published in Journal of Toxicology and Environmental Health, Part A, 2021
T. S. Viana, T. C. R. Rialto, J. F. D. Brito, A. F. D. Micas, F. R. Abe, E. A. Savazzi, M.V.B. Boldrin Zanoni, D. P de Oliveira
Bioluminescence is an aerobic oxidation process that involves light production by luciferase enzyme. This enzyme catalyzes the oxidation of luciferin and this process is mediated by reduction of flavin coenzyme mononucletides. The interaction of toxic substances with the bioluminescent bacteria results in an inhibition of light production by these organisms (Girotti et al. 2008). Parvez, Venkataraman, and Mukherji (2006) reported that inhibition of luminescence in a bacterium served as an effective indicator of toxic effects for higher organisms, as re-affirmed by Manfra et al. (2010). When compared with other bacterial assays, the V. fischeri bioluminescence test is considered one of the most sensitive to a wide range of chemicals (Ferrer et al., 2001; Ferraz, Grando, and Oliveira 2011; Gatidou, Stasinakis, and Izatrou 2015; Heinlaan et al. 2008; Leme et al. 2015; Melo et al. 2019; Ranke et al. 2004; Rosado, Usero, and Morillo 2016; Ventura et al. 2014). As illustrated in Figure 2, luminescent light was increased until 25% dilution for the raw sample and until 45% after oxidative treatments, probably due to the salt content in the samples, considering that Vibrio fischeri is a marine organism. After exposure to more concentrated salt samples in conjunction with elevated quantities of toxic compounds (at highest doses), adverse responses were observed for both raw and PW treated with O3 (Figure 2(a,e)). Septer et al. (2015) postulated that metabolic changes affect availability of substrates for luciferase in Vibrio fischeri resulting in diminished luminescent. It is also possible that metabolic alterations trigger a regulatory response that leads to a change in expression of the lux operon, which is associated with the tricarboxylic acid (TCA) cycle leading to decreased luminescence (Septer et al. 2015).