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Bacterial and Viral Photodynamic Inactivation
Published in Barbara W. Henderson, Thomas J. Dougherty, Photodynamic Therapy, 2020
Zvi Malik, Ladan Hava, Benjamin Ehrenberg, Yeshayau Nitzan
Hemin, the iron-containing protoporphyrin, is the catalytic center of peroxida-tive enzymes and a carrier of oxygen in other proteins. In addition, hemin possesses catalytic activities without its specific apoproteins. Therefore, hemin exerts destructive activity toward biological structures in the presence of oxygen. Hemin can inactivate proteins, probably through cross-linking effects [20,21]; oxidize fatty acids; mimic the enzymelike activity of peroxidase [22,23]; and induce DNA breakages and DNA scission [24]. The main mechanisms of its action are based on the presence of either hydrogen peroxide and a halide ion or oxygen and a reducing agent [25]. Cytotoxic effects of hemin have been studied in eukaryotic cell systems, leukemic lymphocytes, platelets, and erythrocytes [26,27]. Hemin was shown to exert antibacterial activity in the dark [28,29]. Again, the mechanism of this action is probably based on the catalysis of oxidation and epoxidation reactions. Unfortunately, bacterial cultures treated with hemin recover several hours after the hemin treatment. Similar to porphyrins’ photodynamic activity, hemin inhibits only gram-positive bacteria, without any effect on gram-negative cells.
Bioluminescence- and Chemiluminescence-Based Fiberoptic Sensors
Published in Loïc J. Blum, Pierre R. Coulet, Biosensor Principles and Applications, 2019
Loïc J. Blum, Sabine M. Gautier
The chemiluminescence reaction of luminol (5-amino-2,3-dihydrophthalazine-l,4-dione) with hydrogen peroxide requires the use of a catalyst and/or a cooxidant (8). The oxidation reaction that occurs under alkaline conditions is Ferricyanide, which is both a catalyst and a cooxidant, oxidizes luminol. It is then reduced to ferrocyanide and reoxidized to ferricyanide. Hemin (or hematin) can also be used as a catalyst or cooxidant. Peroxidase (EC 1.11.1.7), which remains unchanged after the reaction, is an example of a catalyst. The use of this enzyme has the advantage over ferricyanide in that the chemiluminescent reaction can proceed at near neutral pH values (9). Another way to produce light from luminol and hydrogen peroxide is electrogenerated chemiluminescence (10,11). Using a positively biased electrode luminol is oxidized, and in the presence of hydrogen peroxide the light emission occurs. () Luminol+2H2O2+OH→cooxidantcatalystor3-aminophthalate+N2+3H2O + hvCoupled bacterial bioluminescence reaction.
Exogenous Hemin alleviates cadmium stress in maize by enhancing sucrose and nitrogen metabolism and regulating endogenous hormones
Published in International Journal of Phytoremediation, 2023
Meng Zhao, Yao Meng, Yong Wang, Guangyan Sun, Xiaoming Liu, Jing Li, Shi Wei, Wanrong Gu
Hemin is separated and purified from animal blood and can also be synthesized artificially (Lin et al. 2012). In recent years, researchers have begun to pay attention to the application of Hemin in horticultural crops and field crops, and to explore the effect of Hemin on plants resistance to abiotic stresses such as heavy metals salt and alkali stress (Liu 2017; Qin et al. 2017; Liu 2018). Many previous studies mainly focused on the physiological and biochemical responses to cadmium stress and the differences among different varieties. Studies have shown that exogenous hemin can significantly alleviate the oxidative damage of Alfalfa caused by mercury stress (Han et al. 2007); Hemin treatment can alleviate the inhibition of root elongation caused by salt stress and enhance the salt tolerance of wheat (Xie et al. 2011). Tobacco seedlings treated with hemin can participate in induced ion regulation, reduce ion accumulation and alleviate the damage caused by salt stress to tobacco seedlings (Liu et al. 2018). Hemin treatment reduced the lipid peroxidation of wheat cells, increased glutathione peroxidase activity, significantly improved the salt resistance of wheat seedlings, and increased the resistance of rice to cadmium stress (Huang et al. 2006; Chen 2016b). The plant root system is the first organ to sense cadmium stress signals. The research shows that hemin can participate in the induction and regulation of the formation of plant root morphology and promote the formation of lateral roots such as tomato and Soybean (Balestrasse et al. 2006; Shi 2009; Zhou 2009; Zhang 2010). As for now, there was research progress on the mechanism of improving cadmium tolerance of maize through exogenous substances, especially the effect of Hemin on maize sucrose and nitrogen metabolism and its hormones regulation mechanism under cadmium stress still undefined (Lin et al. 2012; Kollárová et al. 2018a; He et al.2019; Li et al. 2020; Chen et al. 2021; Liu et al.2021; Sun et al.2021b). Our study used artificial climate and illumination and nutrient solution design to explore the mechanism of sucrose metabolism, nitrogen metabolism, and hormone regulation under cadmium stress with Hemin, which provide a practical basis for Hemin application to maize field resilience production.