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Regulation of Osmolytes Syntheses and Improvement of Abiotic Stress Tolerance in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Ambuj Bhushan Jha, Pallavi Sharma
Proline accumulation and its osmoprotective role under abiotic stresses have been reported in detail; however, not much has been discussed on the effect of regulatory molecules and signals on the expression of genes involved in proline’s biosynthetic pathway. In plants, the plastid and cytosol are the sites for proline biosynthesis, whereas degradation occurs in mitochondria (Ashraf and Foolad, 2007). Higher proline accumulation could be due to either activation of the biosynthetic pathway or inactivation of the degradation. In the proline biosynthetic process, pyrroline-5-carboxylate synthetase (P5CS) catalyzes the conversion of glutamate to glutamate semialdehyde (GSA), and GSA gets converted to pyrroline 5-carboxylate (P5C) by spontaneous cyclization (Kavi Kishor et al., 2005). P5C is reduced to proline by enzyme pyrroline-5-carboxylate reductase (P5CR). Alternatively, in plants, proline is also synthesized from arginine/ornithine (Adams and Frank, 1980; Bryan, 1990). The enzyme arginase converts arginine to ornithine. Ornithine is transaminated to P5C by orinithine-δ-aminotransferase (OAT) (Armengaud et al., 2004; Verbruggen and Hermans, 2008). Degradation of proline in mitochondria is catalyzed by the enzyme proline dehydrogenase or proline oxidase (PDH/PRODH), which converts proline to P5C, and then P5C dehydrogenase (P5CDH) produces glutamate from P5C (Joshi et al., 2010; Szabados and Savouré, 2010; Servet et al., 2012). P5CS is the rate-limiting enzyme for the biosynthesis, whereas PDH is the rate-limiting enzyme for the catabolism of proline (Ashraf and Foolad, 2007; Slama et al., 2015).
Recent Advances in Diagnosis: Nano-Based Approach
Published in Anjana Pandey, Saumya Srivastava, Recent Advances in Cancer Diagnostics and Therapy, 2022
Anjana Pandey, Saumya Srivastava
This technique is considered a prominent method for bioanalytical applications due to its miniaturized nature, the low voltage required for driving, and large-scale production without requiring a reference electrode. To detect the alpha-fetoprotein (AFP), a liver cancer biomarker (Mizejewski, 1994; Wong et al., 2015; Komaki et al., 2017; Nguyen et al., 2017; Attia et al., 2018; Moazeni et al., 2018; S. Yang et al., 2018) conductometric immunoassay method was developed. It was based on enzyme-doped silica beads of nanometer size. At first, urease was doped onto the silica nanoparticles by the reverse micelle method. After that, anti-AFP antibodies labeled with arginase were conjugated covalently onto the surface of the synthesized nanoparticle. A sandwich-type immunoassay was executed in an antibody-coated microplate captured with a monoclonal anti-AFP. In this assay, the recognition element used was bienzymatic-functionalized silica nanobeads. Upon introducing the L-arginine, the substrate got divided into urea and L-ornithine by the enzymatic reaction of arginase (Hermanson, 2008). Urea then broke down to ammonia (NH3) and bicarbonate (HCO) ions via urease activity, leading to a change in the internal conductivity of the detection solution at the interdigitated conductometric transducer. The designed immune sensing method has shown excellent conductometric response towards the AFP under optimum conditions in the linear range 0.01–100 ng per mL with LOD of 4.8 pg/mL (Liang et al., 2019(b)). Significantly better reproducibility, greater specificity, and higher accuracy were developed for liver cancer patient serum samples. Liang 2019
A review on bio-functional models of catechol oxidase probed by less explored first row transition metals
Published in Journal of Coordination Chemistry, 2022
Rashmi Rekha Tripathy, Shuvendu Singha, Sohini Sarkar
Manganese is an essential metal in biological processes like metabolism and bone formation [40]. It is present in several metalloproteins and enzymes as a critical component. Metalloenzymes like superoxide dismuthase (SOD), dioxygenase, arginase and catalase contain di and mononuclear manganese cores in their active sites. OEC (Oxygen Evolving Centre of photosystem (II)) possesses manganese ions in terminal photo-oxidation of water during photosynthesis. Although not adequate in number, literature already reports manganese complexes in favor of catecholase activities. Availability of stable and variable oxidation states (from IV to II) proffers this metal to involve in bio-catalysis and hence the preparation of manganese-based biomimics with appropriate ligands. In fact, manganese is one of the best candidates for in vitro catalysis and may be the best choice for designing efficient bio-functional models of catechol oxidase. Recently, Chattopadhyay and his group reported a mononuclear Mn(II)-based catalyst which showed turnover number of 3.10 × 106 h−1, even higher than the highest catalytic rate reported for mononuclear copper(II)-based systems (3.46 × 105 h−1) [41].
Hemolysis during short-term mechanical circulatory support: from pathophysiology to diagnosis and treatment
Published in Expert Review of Medical Devices, 2022
Tim Balthazar, Johan Bennett, Tom Adriaenssens
Hemolysis can lead to a self-perpetuating cycle of multi-organ thrombosis and injury (as shown in Figure 2). The mediators released by destructed RBC’s exert pro-thrombotic effects. Plasma-free hemoglobin (pfHb) plays a crucial role; it scavenges circulating nitric oxide (NO) and reduces von Willebrand factor degradation [26]. Also, arginase from the RBC consumes L-arginine, which is needed for endothelial NO production [28]. This leads to vasoconstriction and reduced NO-mediated platelet inhibition. In addition, small-membrane vesicles, carbon monoxide as well as iron are released in the circulation to exert pro-thrombotic effects and further stimulate the negative spiral of thrombosis, vasoconstriction, and ischemia-reperfusion [26,28]. Locally in the kidney, the accumulation of large amounts of hemoglobin derivatives (heme, heme proteins, and hemosiderin) in the cells of the proximal tubule can lead to acute tubular necrosis (ATN) because of direct cytotoxicity, endothelial dysfunction, and renal vasoconstriction [29,30]. Moreover, the formation of methemoglobin casts in the distal tubule may cause intrarenal obstruction, eventually worsening the injury to the proximal part of the tubule. These mechanisms explain how the kidney is often the first organ to suffer from failure in the case of severe intravascular hemolysis [29,30]
The association between manganese exposure with cardiovascular disease in older adults: NHANES 2011–2018
Published in Journal of Environmental Science and Health, Part A, 2021
Shengjue Xiao, Yufei Zhou, Tao Liu, Yue Hu, Qi Wu, Qinyuan Pan, Xiaotong Wang, Ailin Liu, Jie Liu, Hong Zhu, Ting Yin, Defeng Pan
Mn is an essential micronutrient required for regulation of intracellular activities, including antioxidant defenses, energy metabolism, ammonia detoxification and protein synthesis (mediated by, e.g., glutamine and arginase synthase).[20,21] However, excessive Mn exposure is toxic. Jiang and Zheng[10] found that excessive Mn exposure could cause cardiovascular toxicity via inhibition of myocardial contraction in different species. Huang et al.[22] confirmed that occupational Mn exposure may cause an increase in creatine kinase-MB, which is an indicator of the myocardial damage. Although a trace element, Mn intake via daily food, water and air is typically within an appropriate range. There has been little research on the correlation between Mn exposure and CVD. A previous study found that a higher concentration of urinary Mn could protect against hypertension,[11] showing the benefits of Mn exposure in healthy people. Based on this result it might be worth studying workers exposed to excessive amounts of Mn, since in that case blood pressure might decline significantly and lead to adverse cardiac events. In the current study, the participants were elderly Americans in the NHANES database with CVD from 2011–2018; adjustments to the variables allowed those exposed to high Mn levels to be excluded. Thus, higher levels of Mn (range mean ± SD) should be considered beneficial for CVD.