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Nano-Bio Hybrid Platform to Meet the Energy Challenge
Published in Keka Talukdar, Nanomaterials-Based Composites for Energy Applications, 2019
Schiff base associates the retinal chromophore to the opsinapoproteinviaLysine-216 amino acid residue. Schiff base is a molecule having N atom bound to a C atom on one side by a C=N double bond and to a carbon on the other side by a C-N single bond. A proton can reversibly attach to the N atom, which acts as a proton stockpile. BR proton pumps with a molecular weight ~ 26.5 kDa are relatively small protein architectures. When the retinal chromophore absorbs a photon, it becomes energized and experiences a conformational change that leads to a change to an advanced energy state which results in the deposited proton to be unconfined. Therefore, in the presence of light, the purple membrane protons get released into the extracellular side of the cell membrane. These protons do not go away, but are directed back into the cell. Protons are positively charged, and intercellular side of the membrane is negatively charged with an electrochemical potential up to 250 millivolts. Therefore, BR is capable of carrying ions against an electrochemical potential with 10,000-fold difference in proton concentration on either side of the membrane [29]. This electrochemical potential is used in photophosphorylation to produce ATP. As the ATP synthesis is done in BR without having no chlorophyll molecule; therefore, the mechanism is known as “non-chlorophyll photosynthesis.”
Abiotic Stress in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Ashutosh K. Pandey, Annesha Ghosh, Kshama Rai, Adeeb Fatima, Madhoolika Agrawal, S.B. Agrawal
At the physiological level, the photosynthetic rate varies with climatic conditions, plant species, cultivars, photosynthetically active radiation (PAR) and UV-B. Earlier reports have clearly presented the damage induced with the exposure of UV-B radiation on the photosynthetic machinery, thylakoid membrane, light harvesting complexes and both the photosystems (I and II), causing deleterious impact on the assimilative performance of the plants. Photosystem II is one of the most sensitive components of photophosphorylation and is responsible for the splitting of water in the presence of light (Correia et al., 1999; Kakani et al., 2003; Savitch et al., 2001). Correia et al. (1999) have reported significant reduction of photosynthesis by 25–46% in wheat crop under elevated doses of UV-B compared to ambient conditions. Photosynthesis in plants is also regulated by an important factor, stomatal conductance; several studies have demonstrated that elevated UV-B leads to the reduction of stomatal conductance and, hence, is responsible for CO2 assimilation to some extent (Zhao et al., 2003). Jansen summarized that stomata exposed to elevated UV-B lose their ability to readjust and regulate their original functioning, leading to the partial opening of stomata.
Turfgrass Physiology and Environmental Stresses
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Overall, the electron transport system accomplishes the transfer of electrons (energy) from H2O to NADP+ to form NADPH with the evolution of O2 and the production of ATP as previously discussed. NADPH is vital for the reduction of CO2, and ATP is an energy-carrying molecule used in many energy-requiring processes including various synthesis reactions (e.g., the synthesis of proteins). The formation of ATP is referred to as photophosphorylation.
Ozone: An Advanced Oxidation Technology to Enhance Sustainable Food Consumption through Mycotoxin Degradation
Published in Ozone: Science & Engineering, 2022
O. J. Sujayasree, A. K. Chaitanya, R. Bhoite, R. Pandiselvam, Anjineyulu Kothakota, Mohsen Gavahian, Amin Mousavi Khaneghah
The major fusarium toxins in food are fumonisins, trichothecenes, zearalenone, and emerging mycotoxins such as beauvericin and enniatins fusaproliferin, and moniliformin. In cereal-based foods, these generally occur either singly or in combinations with other mycotoxins, such as aflatoxins (Sadiq et al. 2019). The patulin is produced by fungi, such as Penicillium, Aspergillus, and Byssochlamys species. It is a usual contaminant in fruit and vegetable products, especially in apples. Damages to the vital organs, such as the kidney and liver, are seen in vitro toxicity assessments (Pal, Singh, and Ansari 2017). Among more than 70 phytotoxins synthesized, the alternaria mycotoxins produced by Alternaria are chemically characterized and reported to cause mycotoxicosis (EFSA, 2011b). The groups like alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxins (ATX-I and II), tenuazonic acid (TeA), and iso-tenuazonic acid (iso-TeA) belongs to Alternaria toxins (Marin et al. 2013). Myotoxicity is seen in carcinogenicity, mutagenicity, DNA strand breaks, photophosphorylation, and enzyme activity inactivation (Escriva et al., 2017). Ergot alkaloids (EAs) are toxic components that usually infect major grain cereals, and they are present in Claviceps species. It majorly affects the nervous system. Hodgson (2012) reported that ingestion of contaminated rye (Secale cereale) caused gangrenous and convulsive ergotism epidemics.