China 
Africa 
Explore chapters and articles related to this topic
Remediation of Selenium-Polluted Soils and Waters by Phytovolatilization
Published in Norman Terry, Gary Bañuelos, of Contaminated Soil and Water, 2020
Adel Zayed, Elizabeth Pilon-Smits, Mark deSouza, Zhi-Qing Lin, Norman Terry
We have genetically engineered Indian mustard plants which overexpress cysteine synthase (CS), using a construct that contains the spinach CS gene, fused to a chloroplast transit sequence, under the control of the 35S promoter (Saito et al., 1994). The CS enzyme activity in leaves of transgenic CS plants was about twofold higher than in untransformed plants. The transgenic CS plants did not show any significantly different rates of Se volatilization or Se accumulation when supplied with selenate or selenite. Thus, we can conclude that the CS enzyme is not rate-limiting for Se accumulation or volatilization under our assay conditions. Again, this finding is in agreement with our XAS data, which show that selenite-supplied wildtype plants accumulate selenomethionine and, therefore, that the step mediated by CS is a very rapid one in wildtype plants, and not likely to be rate-limiting.
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
To test if OsRCS3 is able to synthesize cysteine, we expressed the gene in the cysteine synthase-deficient E. coli strain NK3. The mutant strain transformed empty vector was unable to grow on M9 medium without cysteine. While heterologous expression of OsRCS3 restored the growth of the E. coli strain NK3 on the medium.
Plant-Nanoparticles (Np) Interactions—a Review: Insights into Developmental, Physiological, and Molecular Aspects of Np Phytotoxicity
Published in Megh R Goyal, Sustainable Biological Systems for Agriculture, 2018
Although transcriptional analyses have been widely used to study the molecular basis of NP toxicity in a variety of organisms including microbes, humans, mammalian cell lines, and other model organisms,8 only limited investigations have been conducted to assess the molecular mechanism of the ENP-plant interactions and NP phytotoxicity. For example, gene expression analyses of the model plant A. thaliana by RT-PCR have provided new insights into the molecular mechanisms of plant response to Ag NPs. Dimkpa et al.29 investigated that exposure of commercial Ag NPs to wheat in a sand growth matrix induced plant defense response in Arabidopsis plants, as revealed by significant upregulation of pathogenesis-related (PR1, PR2, and PR5) genes involved in systemic acquired resistance (SAR).23 Similarly, the transcriptional response of A. thaliana exposed to Ag NPs were analyzed using whole genome cDNA expression microarrays, which resulted in upregulation of 286 genes and downregulation of 81 genes as compared to the control.62 Real-time PCR analysis showed significant transcriptional modulation of genes involved in sulfur assimilation and glutathione biosynthesis,i.e., adenosine triposphate sulfu- rylase (ATPS), 3’-phosphoadenosine 5’-phosphosulfate reductase (APR), sulfite reductase (SiR), cysteine synthase (CS), glutamate-cysteine ligase (GCL), glutathione synthetase (GS2) with upregulation of glutathione S-transferase (GSTU12), glutathione reductase (GR), and phytochelatin synthase (PCS1) genes.105 In another study by the same group, the expression of cell cycle genes proliferating cell nuclear antigen (PCNA) and DNA mismatch repair (MMR) were found to be modulated as the results of oxidative stress caused by Ag NPs exposure in A. thaliana.106 MicroRNAs (miRNAs) are a newly discovered post-transcriptional gene regulators, which belong to small endogenous class of noncoding RNAs (□ 20-22 nt). Interestingly, miRNAs have also been shown to play an important role in plant response to NPs by regulating gene expression. In a study by Frazier et al.,40 nano-TiO2 exposure to tobacco plants significantly affected the expression profiles of miRNAs, with miR395 and miR399 exhibiting the greatest fold changes of 285-fold and 143-fold, respectively.
Growth and genetic analysis of Pseudomonas BT1 in a high-thiourea environment reveals the mechanisms by which it restores the ability to remove ammonia nitrogen from wastewater
Published in Environmental Technology, 2022
Jingxuan Deng, Zhenxing Huang, Wenquan Ruan
S metabolism is also complete in BT1. First, the available S sources are quite abundant, such as extracellular S sources sulphate, taurine, and alkanesulfonate, and intracellular S sources thiosulphate and dimethyl sulphone. Extracellular S sources can be transported into cells by the sulphate or thiosulphate transport system (cysP, sbp, cysU, cysW, and cysA), taurine transport system (tauA, tauB, and tanC), and sulphonate transport system (ssuA, ssuB, and ssuC), and are converted into sulphate and sulphite by taurine dioxygenase (tauD) or alkanesulfonate monooxygenase (ssuD). Thiosulphate in cells can be converted into Sulphate and Sulphite by sulphur-oxidizing protein SoxY (SoxY) and thiosulphate sulfurtransferase (TST, glpE), respectively. Dimethyl sulphone can be converted into sulphite by FMN reductase (ssuE) and alkanesulfonate monooxygenase (ssuD). Sulphate in cells is converted into sulphite by sulphate adenylyltransferase (cysD), bifunctional enzyme (cysNC), and phosphoadenosine phosphosulfate reductase (cysH), and then sulphite is converted into sulphide by the enzymes NADPH and flavoprotein (cysJ, cysI). Sulphide can continue to be metabolised in two ways: the first is that sulphide reacts with L-homoserine to generate succinate and L-homocysteine under the action of homoserine O-acetyltransferase (metX) and O-succinylhomoserine sulfhydrylase (metZ); the other is that sulphide reacts with serine O-acetyltransferase (cysE) and cysteine synthase (cysK) to generate L-cysteine and acetate under the action of serine O-acetyltransferase (cysEand) cysteine synthase (cysK). Among these compounds, acetate and succinate are important intermediate substances in the C cycle. In addition, sulphide can form polymers under the action of quinone oxidoreductase (sqr) (Figure 2).
Phytoremediation and detoxification of xenobiotics in plants: herbicide-safeners as a tool to improve plant efficiency in the remediation of polluted environments. A mini-review
Published in International Journal of Phytoremediation, 2020
Daniele Del Buono, Roberto Terzano, Ivan Panfili, Maria Luce Bartucca
As stated above, another important route of the herbicide detoxification is the conjugation of the xenobiotic with the tripeptide GSH (see 3.2). This reaction is catalyzed by the GSTs, a family of enzymes very active in the phase (ii) of the herbicide metabolism. Safeners can enhance the conjugation of thiocarbamates, chloro-s-triazines, triazinone sulfoxides, chloroacetanilides, diphenylethers, some sulfonylureas, aryloxyphenoxypropionates, thiazolidines, and sulfonamides herbicides with GSH (Jablonkai 2013), either by inducing the activity of GSTs or by elevating the cellular levels of reduced glutathione (GSH) (Farago et al.1994; Kocsy et al.2001). The increase of the glutathione content in plant cells can be promoted by safeners by (i) regulating the activities of the first two enzymes of the assimilatory sulfate reduction in higher plants: ATP sulfurylase (ATPS, E.C. 2.7.7.4) and adenosine-5'-phosphosulfate sulfotransferase (APSSTase) (Farago et al.1994); (ii) regulating the sulfate incorporation into cysteine, e.g. by increasing cysteine synthase (CS, E.C. 4.2.99.8) activity (Hirase and Molin 2001); (iii) activating the key enzymes involved in the biosynthesis of GSH: glutathione synthetase (GS, E.C. 6.3.2.3) and y-glutamylcysteine synthetase (y-ECS, E.C. 6.3.2.2) (Hatzios and Burgos 2004); and (iv) inducing the activity of glutathione reductase (GR, E.C. 1.6.4.2), a NAD(P)H-dependent oxidoreductase which converts oxidized glutathione (GSSG) in reduced glutathione (GSH) (see 3.1.2; Gill et al.2013). At last, it has been demonstrated that the safener-mediated induction of GSH in plant for the high antioxidant potential of this tripeptide, is also functional in counteracting the oxidative stress caused by ROS (see 3.1.2) (Edwards, Brazier-Hicks et al.2005). As reported for Cyt P450, the expression of GST by safeners has been reported not only in graminaceous crops but also in dicotyledonous weeds (e.g. Arabidopsis thaliana) (DeRidder et al.2002).