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Molecular Aspects of the Activity and Inhibition of the FAD-Containing Monoamine Oxidases
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
MAO enzymes in the periphery are important for metabolism of exogenous amine compounds. Ingested amines have variable proportions present as the neutral compound that can diffuse cross membranes. Where there is a pH difference, such as between cytosol and the mitochondrial matrix, reprotonation results in accumulation of the charged species in the new compartment. The mitochondrial transmembrane potential also favours retention of positively charged amines. Biogenic amines from the diet, principally tyramine, are extensively metabolized in the intestinal wall by MAO A (Anderson et al., 1993). If tyramine increases in the circulation, complex sympathetic nervous system perturbations ensue, with consequent vasoconstriction and bradycardia (reviewed in Finberg and Gillman (2011)). Tyramine accumulation results in this “cheese effect” when MAO A in the gut and MAO A and MAO B in the liver are inhibited by non-selective drugs such as tranylcypromine or phenelzine. The tyramine-induced cheese effect is avoided by using selective MAO B inhibitors such as selegiline in adjunct therapy of Parkinson’s disease or reversible inhibitors of MAO A in depression (Lum and Stahl, 2012).
Algicidal bacteria against cyanobacteria: Practical knowledge from laboratory to application
Published in Critical Reviews in Environmental Science and Technology, 2023
Jesús Morón-López, Liliana Serwecińska, Łucja Balcerzak, Sława Glińska, Joanna Mankiewicz-Boczek
Unlike tryptoline, the algicidal effect of tyramine and prodigiosin was dependent on the species of cyanobacteria and green algae tested (Figure 5). These compounds exerted a high lytic effect on most filamentous cyanobacteria and also influenced green algae, particularly to PbSAG. However, in contrast to other studies at the same compound concentration, their algicidal effect on the three strains of M. aeruginosa and the strain RrCS was low or absent. Tyramine is an aromatic compound from the family of phenols that occurs widely in nature as a result of biological activity. Its algicidal effect was first observed on M. aeruginosa after exposure to a cell-free filtrate of Acinetobacter guillouiae A2 (Yi et al., 2015). In our previous study, tyramine was also present in the algicidal attack of M. morganii against the environmental strain MaPN (Mankiewicz-Boczek et al., 2022). To date, its algicidal mechanism is mostly unknown, but the fact that tyramine is a trace substance derived from tyrosine, i.e., a biogenic amine, could suggest that its algicidal effect occurs in the presence of other compounds produced from the transformation and degradation of amino acids. This could explain the variable algicidal effect caused by tyramine when added as a single compound in this study. The algicidal activity of prodigiosin was somewhat stronger than tyramine (Figure 5). Prodigiosin is a red linear tripyrrole pigment produced by a number of Gammaproteobacteria, such as species of Enterobacter (B. Zhang et al., 2022), Hahella (D. Kim et al., 2008; Nakashima et al., 2006; K. Yang et al., 2017), Pseudoalteromonas (Setiyono et al., 2020; X. Wang et al., 2021; Y. Wang et al., 2012), Serratia (F. Yang et al., 2013), and Vibrio (Danevčič et al., 2016) (Table S1 in the SI). It has been widely documented as a potent antimicrobial compound against a wide range of Gram-positive and Gram-negative bacteria (Danevčič et al., 2016; Yip et al., 2021), as well as harmful algae from marine environments (D. Kim et al., 2008; Nakashima et al., 2006; S. Zhang et al., 2020). A few studies reported its algicidal activity on the cyanobacterial species of M. aeruginosa and Anabaena cylindrica (Wei et al., 2020; F. Yang et al., 2013; K. Yang et al., 2017; B. Zhang et al., 2022). Studies have shown that prodigiosin generates ROS production that induces lipid peroxidation, alters the antioxidant system, and disrupts cell photochemistry, triggering apoptotic-like or necrotic-like cell death in M. aeruginosa (Wei et al., 2020; K. Yang et al., 2017). According to Yang et al. (2013), the algicidal activity of prodigiosin on different M. aeruginosa strains varied in a concentration dependent manner. Therefore, the variable effect observed in the M. aeruginosa and R. raciborskii strains tested in the present study may be due to different lethal dose thresholds and thus different sensitivity to the pigment between strains.