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The Role of Botanicals in Cardiovascular Health
Published in Stephen T. Sinatra, Mark C. Houston, Nutritional and Integrative Strategies in Cardiovascular Medicine, 2022
Beetroot is gaining popularity for its purported benefits on cardiovascular function and athletic performance. In fact, the global market for beetroot juice is increasing by 5% per year and shows no signs of slowing (Zamani et al. 2021). Beetroots, like spinach, lettuce, chard, and radishes, are a rich source of inorganic nitrates. Approximately 25% of the nitrate that enters the circulation from the gut becomes concentrated in the salivary glands through active uptake by the sialin transporter, and the rest is excreted by the kidneys (Gee and Ahluwalia 2016). Upon interaction with oral bacteria, nitrate is reduced to nitrite, swallowed, and absorbed, increasing plasma nitrite levels. Endogenous nitrite reductases reduce plasma nitrite to the bioactive nitric oxide (NO), which acts as a vasodilator (Lundberg et al. 2008). Of interest, antiseptic mouthwashes may eliminate up to 94% of the oral commensal bacteria that reduce nitrate to nitrite. Clinical trials show that the effects of antihypertensive drugs are inhibited (totally or partially) in subjects using this type of mouthwash (Oliveira-Paula et al. 2019).
Carbon Dioxide Sequestration by Microalgae
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
G.V. Swarnalatha, Ajam Shekh, P.V. Sijil, C.K. Madhubalaji, Vikas Singh Chauhan, Ravi Sarada
The C:N ratio plays an important role in microalgal growth. CO2 supplementation to microalgal cultures was noted to up-regulate the genes involved in nitrogen acquisition and assimilation (Peng et al. 2016). The genes encoding nitrate/nitrite transporter and ammonium transporters were observed to be up-regulated by CO2 supplementation to microalgae. In addition, the genes encoding enzymes involved in the assimilation of extracellular nitrogen into ammonium including nitrate reductase and nitrite reductase were up-regulated by CO2 supplementation (Peng et al. 2016).
Introduction
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
It has not been possible to cover all the copper proteins and copper enzymes. Typical representatives are missing, like urate oxidase (uricase) (EC 1.7.3.3)29,30 and nitrite reductase (EC 1.7.99.3).31,32
Reconsidering anion inhibitors in the general context of drug design studies of modulators of activity of the classical enzyme carbonic anhydrase
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Alessio Nocentini, Andrea Angeli, Fabrizio Carta, Jean-Yves Winum, Raivis Zalubovskis, Simone Carradori, Clemente Capasso, William A. Donald, Claudiu T. Supuran
Apart the active site metal ion, hCA II has an additional metal binding site, at its entrance42. Copper(II) binds rather efficiently in this additional site, being coordinated by His64, His4 and several water molecules33,42. This form of the enzyme, with Zn(II) at its active site and Cu(II) at the secondary site is referred to as Zn/Cu-hCA II, in contrast to the enzyme which has zinc substituted by copper also within the catalytic centre (Cu2-hCA II)43. Recently, McKenna’s group proposed that the Cu2-hCA II also has nitrite reductase activity, with nitrite being initially coordinated (as a bidentate ligand) to the active site copper ion (Figure 4(B)). In contrast, as mentioned also above, the Zn/Cu-hCA II was observed with an O2 molecule coordinated to zinc (Figure 4(B)), which most probably is a superoxide anion (or anion radical), as suggested by computational techniques33. A major overall conclusion is that all serious studies performed to date on hCA II demonstrate that anions are coordinated to the metal ion in the enzyme active site.
The relationship between gastric microbiota and gastric disease
Published in Scandinavian Journal of Gastroenterology, 2019
Shuyi Zhang, Dan Shi, Muran Li, Yanru Li, Ximo Wang, Wen Li
Sharma et al. reported that the secretion of gastric acid in CAG patients is reduced but that the abundance of bacteria in the stomach is increased. The increase of bacteria was positively correlated with the concentration of nitrite in the stomach [28]. Nitrite is the precursor of endogenous N-nitroso compounds. The cytochrome-cd1-nitrite reductase of bacteria could catalyze the conversion of nitrite to nitrosamine in the presence of secondary amine factors [29]. Nitrosamines play an important role in promoting the development and progression of CAG, which may eventually lead to gastric cancer. However, Parsons et al. recently reported that H. pylori-induced CAG resulted in lower bacterial abundances and diversity [30].
Drug targets in dormant Mycobacterium tuberculosis: can the conquest against tuberculosis become a reality?
Published in Infectious Diseases, 2018
Vivek Kumar Gupta, M. Madhan Kumar, Dharmendra Singh, Deepa Bisht, Shweta Sharma
Reduction of nitrate to nitrite is mediated by four genes viz. narG, narH, narJ and narI, clustered together as narGHJI in an operon. The induced expression of nitrate reductase (NarGHJI) has been reported during the dormant stage in the absence of oxygen. Nitrite is subsequently reduced to ammonia by nitrite reductase (NirBD) using the NADH pool as electron donor. Ammonia is assimilated into the central metabolite glutamate using the glutamine synthetase–glutamine 2-oxoglutarate aminotransferase (GS-GOGAT) pathway [48].