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O-acetylserine(thiol)lyase and regulates arsenic accumulation in rice
Published in Yong-Guan Zhu, Huaming Guo, Prosun Bhattacharya, Jochen Bundschuh, Arslan Ahmad, Ravi Naidu, Environmental Arsenic in a Changing World, 2019
Complexation of arsenite by thiols is an important mechanism of arsenic (As) detoxification in non-hyperaccumulating plants. Plants could decrease the translocation of As from roots to shoots by increasing the synthesis of a range of thiol-containing compounds in roots (Liu et al., 2010). Cysteine biosynthesis is a central metabolic pathway to incorporate inorganic sulfur into organic molecules. In plants, cysteine is synthesized from O-acetyl-L-serine and sulfide by O-acetylserine(thiol)lyase (OAS-TL). OAS-TL activity is present in the cytosol, plastids and mitochondria (Hell et al., 2002). In the present study, we investigated the As accumulation of rice (Oryza sativa) T-DNA insertion mutants for OsRCS3.
Recombinant production of active Streptococcus pneumoniae CysE in E. coli facilitated by codon optimized BL21(DE3)-RIL and detergent
Published in Preparative Biochemistry and Biotechnology, 2019
Deepali Verma, Monika Antil, Vibha Gupta
The cysteine amino acid, containing thiol moiety, is involved in many cellular functions and is also a constituent of several biomolecules.[5]De novo cysteine biosynthesis is a conserved pathway in bacteria.[6,7] This pathway comprises two enzymes namely (i) Serine acetyltransferase (SAT) or CysE which catalyzes the formation of O-acetyl- L-serine (OAS) from L-serine and acetyl-CoA and (ii) Pyridoxal 5' phosphate-dependent O-acetylserine sulfhydrylase (OASS) or CysK, that converts OAS in the presence of sulfide or thiosulfate to L-cysteine (Fig. 1).[8] Fortunately, biosynthesis of cysteine follows a different route in humans and both CysE and CysK are absent in Homo sapiens.[9]cysE gene is listed as essential in the Database of Essential Genes (DEG) [10] for several human pathogens such as E. coli,[10]H. influenza,[11]S. aureus,[12]M. tuberculosis,[7,13,14] and B. subtilis.[6] As CysE appears to be essential for multiple bacterial species, its inhibition in S. pneumoniae may also be disruptive to its growth.
Remediation of atmospheric sulfur and ammonia by wetland plants: development of a study method
Published in International Journal of Phytoremediation, 2022
Mohamed Kanté, Servane Lemauviel-Lavenant, Jean-Bernard Cliquet
Volatile Inorganic pollutants, such as S and N gases can be used by plants as sources of nutrients, they then constitute complementary sources with pedospheric nutrients (Rennenberg and Polle 1994; Krupa 2003; Castro et al. 2005; De Kok et al. 2007). Atmospheric S can also be used as a nutrient even when no pollutants are added to the atmosphere. Recently, it has been shown that atmospheric S is a source of S for grassland species in a non-enriched atmosphere (Cliquet and Lemauviel-Lavenant 2019). In Trifolium repens, grown in a non-S-enriched atmosphere, S from atmospheric deposition on the leaves may account for one-third of the total S of the plant if sulfate concentration is low in the pedosphere (Varin et al. 2010). The main forms of atmospheric S are hydrogen sulfide (H2S) and sulfur dioxide (SO2). The foliar uptake of S proceeds via the cuticle and, to a larger extent, via stomata (De Kok et al. 1997; De Kok et al. 2002; Kumar et al. 2019). Inside the leaves, H2S is directly metabolized into cysteine through the activity of O-acetylserine lyase and subsequently into other organic S compounds (De Kok et al. 2007). SO2 is converted into sulfite and/or bisulfite ions in the aqueous phase of the apoplast and/or within the cell, and SO3 can then be oxidized to sulfite or reduced to organic S (De Kok et al. 2007). Atmospheric NH3 can also be used as a source of nitrogen for plants and Castro et al. (2008) have shown, with Brassica oleracea, that atmospheric NH3 could compensate for plants deprived of nitrate and make it possible to maintain both the dry matter and the protein contents. The NH3 deposition rate appears to depend on its concentration in the atmosphere (Jones et al. 2007). The foliar uptake of ammonia occurs, as for atmospheric S, via the cuticle and, to a larger extent, via stomata (Flechard et al. 2015). Ammonia is metabolized to amino acids through the GS/GOGAT pathway (Pearson and Stewart 1993). Actually, plant shoots can be either a source or a sink of SO2, H2S, or NH3, depending on the concentration difference between the atmosphere and the plant substomatal cavity (Rennenberg and Polle 1994; Flechard et al. 2015). Highly fertilized plants can emit these gases, but these pollutants constitute also sources of S and N for plant growth in oligotrophic agroecosystems (De Kok et al. 2007; Jones et al. 2007; Castro et al. 2008; Massad et al. 2010; Flechard et al. 2015).