Antioxidant assays
Roger L. McMullen in Antioxidants and the Skin, 2018
The oxygen radical absorbance capacity (ORAC) assay is another in vitro assay, which uses a fluorescent probe that is susceptible to damage by free radical species. Historically, beta-phycoerythrin, which is a light-harvesting protein from the red algae Porphyridium cruentum, was used as the fluorescent probe in this assay. It is known to undergo damage by peroxyl radicals, resulting in a decrease in its intrinsic fluorescence. An initiator is utilized to generate a radical species that eventually leads to the evolution of peroxy radicals. In a typical experiment, one may monitor the fluorescence as a function of time (fluorescence decay curve) for a control system (initiator + fluorescent probe) and a corresponding system that contains an antioxidant (initiator + fluorescent probe + antioxidant). Ideally, the system containing the antioxidant should inhibit the fluorescence decay induced by the peroxy radicals.
Diversity and Utilization of Marine Cyanobacteria
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
A good amount of work has been carried out to bring out the nanobiotechnological potential of cyanobacteria. For instance, extracellular biosynthesis of silver nanoparticles using the marine cyanobacterium Oscillatoria willei NTDM01 was reported (MubarakAli and Thajuddin, 2009; MubarakAli et al., 2011a). Detailed characterization through UV-vis, FTIR, SEM and EDS spectral analysis revealed that the silver ions were reduced, and a secreted protein stabilizes the silver nanoparticles. Apart from eco-friendliness and easy availability, the low cost of production will also be advantageous when compared to other classes of microorganisms (Mubarakali et al., 2011b). Apart from cyanobacteria as biomass, their accessory pigment C-phycoerythrin (C-PE) was also found useful to synthesize nanoparticles. C-phycoerythrin from Phormidium tenue NTDM05 was used to synthesize CdS nanoparticles; the size of such nanoparticles was found to be about 5 nm. Essentially, the pigment stabilized the CdS nanoparticles. The pigment-labeled CdS nanoparticles could be applied as biolabel (MubarakAli et al., 2012).
Potentials and Challenges in the Production of Microalgal Pigments with Reference to Carotenoids, Chlorophylls, and Phycobiliproteins
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
Phycocyanin derived from S. platensis is used as a colorant in foods, such as chewing gum, ice sherberts, popsicles, candies, soft drinks, dairy products, and jellies (Begum et al., 2016). Phycoerythrin derived from Phorphyridium aerugineum and S. platensis is also used in color confectionary, gelatin, fermented milk products, ice creams, cake decoration, and milk shakes. Because of their intense fluorescence, phycobilins are employed as indicators in clinical and immunological analysis. They can also have applications in the cosmetic industry. Dietary supplements of Chlorella and Spirulina have b een used in powder form, after drying and sieving the biomass (Borowitzka, 2013).
Nanoencapsulation of R-phycoerytrin extracted from Solieria filiformis improves protein stability and enables its biological application as a fluorescent dye
Published in Journal of Microencapsulation, 2023
Jéssica Roberta Pereira Martins, Antonia Livânia Linhares de Aguiar, Karina Alexandre Barros Nogueira, Acrisio José Uchôa Bastos Filho, Thais da Silva Moreira, Márjory Lima Holanda Araújo, Claudia Pessoa, Josimar O. Eloy, Ivanildo José da Silva Junior, Raquel Petrilli
Phycobiliproteins have open-chain tetrapyrrole prosthetic groups, which are covalently linked to cysteine residues of the protein by thioether bonds (Sun et al. 2004). R-Phycoerythrin (R-PE) is a phycobiliprotein found in Rhodophytes algae and which gives the red colour. In the organisms, this pigment acts as antenna for light gathering and a nitrogen reservoir for growth in nitrogen-poor environmental conditions. R-PE is water soluble, presents 240 kDa molecular weight, has three absorption peaks at 498, 539, and 565 nm and fluorescence at 580 nm (Liu et al. 2005, Mittal et al. 2019). The purified R-PE pigment has four subunits with the following molecular weight: α subunit (18 kDa), β subunit (21 kDa), γ subunit (29 kDa), and γ′ subunit (27 kDa) (Nguyen et al. 2019).
Antitumor activities of carboplatin–doxorubicin–ZnO complexes in different human cancer cell lines (breast, cervix uteri, colon, liver and oral) under UV exposition
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Suttirak Pairoj, Pattareeya Damrongsak, Badin Damrongsak, Natini Jinawath, Rossukon Kaewkhaw, Chinnapat Ruttanasirawit, Tanaporn Leelawattananon, Kitsakorn Locharoenrat
As UV-light penetration is weak in vivo, UV-induced cell inhibition was analysed as a control in this study. After the incubation period for the internalization of chemo drugs into human cell lines, optical microscopy was performed to obtain phase contrast images of the treated cells for quantification, and fluorescence microscopy was employed to analyse the position and integrity of the internalized chemo drugs into the same group of cells. As DOX is a fluorescent probe with a bright red colour when visualized with a red filter, images of cellular uptake of the live cells were obtained without adding any staining solution. The fluorescent intensity was quantified by flow cytometry (FCM model: BD FACSCanto, Piscataway, NJ). R-phycoerythrin (R-PE) was used as the fluorescence signal.
Effects of eye drops containing a mixture of 3% diquafosol sodium and tocopherol acetate (vitamin E) on the ocular surface of murine dry eye
Published in Cutaneous and Ocular Toxicology, 2021
Lan Li, Rujun Jin, Ying Li, Hee Su Yoon, Hyeon Jeong Yoon, Kyung Chul Yoon
A multiplex immunobead assay (Luminex 200; Luminex Crop., Austin, TX) was used to measure the concentrations of TNF-α, IL-1β, IL-6, and chemokine CC motif ligand 4 (CCL4) in the conjunctiva, as previously described27–29. Briefly, the conjunctival tissues were collected, pooled, and incubated in a lysis buffer containing protease inhibitors for 30 min. The cell extracts were then centrifuged at 14 000 × g at 4 °C for 15 min and the supernatants stored at −70 °C until further analysis. The total protein concentration of the supernatants was determined, and (10 μg/25 μL) of total protein from each sample was pipetted into the wells of an assay plate. The wells contained the appropriate cytokine and chemokine bead mixture (Millipore, Billerica, MA) and mouse monoclonal antibodies specific for the mixture. The supernatant was washed three times, and the plate incubated for 1 h in the dark at room temperature with a biotinylated detection antibody. The reactions were detected after the addition of streptavidin-phycoerythrin using an analysis system (xPONENT, Austin, TX). The concentrations of tissue cytokines and chemokines were calculated from the standard curves generated using known concentrations of recombinant mouse cytokines and chemokines.
Related Knowledge Centers
- Chlorophyll
- Chloroplast
- Cyanobacteria
- Photosynthesis
- Phycobilin
- Protein Quaternary Structure
- Thylakoid
- Phycobiliprotein
- Phycoerythrobilin
- Phycobilisome