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Marine-Algal Bioactive Compounds
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Iahtisham Ul-Haq, Masood Sadiq Butt, Natasha Amjad, Iqra Yasmin, Hafiz Ansar Rasul Suleria
Among bioactive compounds of algae, its natural pigments, phlorotannins, diterpenes and sulfated polysaccharides have gained significant importance. Algae being a photosynthetic organism contains chlorophylls as a major pigment (Chen et al. 2017). This pigment is converted to pheophorbide, pheophytin and pyropheophytin upon processing which possess plausible cancer preventive perspectives (Chen and Roca 2018a; Chen and Roca 2018b). Among other things, pheophytin has been found to acquire more cytotoxic effects than pheophorbide (Lin et al. 2014). The content of pigments is season dependent as are most of the fucoxanthin, violaxanthin, chlorophyll A and carotene in brown algae (Ascophyllum). Similar seasonal variation is also present in Fucus serratus where lower levels are seen during autumn. Moreover, chlorophyll contents are also influenced with the light exposure as harbored algae showed more pigment as compared to openly grown algae (Chen and Roca 2018b).
Brevetoxin
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
As a microscopic, single-celled, photosynthetic organism, K. brevis utilizes its two flagella to move through the water in a spinning motion usually toward the direction of light and against the direction of gravity, and multiplies rapidly with an influx of nutrients (particularly nitrogen and phosphorus) combined with proper temperature, water, and light conditions, reaching very high concentrations and rendering the water reddish or pinkish (“red tide blooms”) [12]. Subsequent brevetoxin production by K. brevis is influenced by salinity variations, as it tends to generate more toxins during hypoosmotic stress (i.e., salinity reduction), suggesting the possible function of brevetoxin in maintaining sodium concentration within the cell when external sodium concentration is low [13–15]. Further, BTX-2 appears to be the major toxin produced during the log phase, while BTX-3 and BTX-1 increase during the stationary phase.
Exposure to artificial daylight or UV irradiation (A, B or C) prior to chemical cleaning: an effective combination for removing phototrophs from granite
Published in Biofouling, 2018
J. Santiago Pozo-Antonio, Patricia Sanmartín
A single application of benzalkonium chloride after irradiation (step 3) was sufficient to reduce the ChlaF emission close to zero, with significantly lower Fv/Fm values that remained below 0.100 (ie the threshold below which a photosynthetic organism is considered dead) in all samples, irrespective of the type of irradiation.