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Application of Molecular Tools and Biosensors for Monitoring Water Microbiota
Published in Maulin P. Shah, Wastewater Treatment, 2022
Pyrosequencing is a technique developed in 1996 by Mostafa Ronaghi and Pal Nyren at the Royal Institute of Technology in Stockholm. It is a DNA sequencing method that works on the principle of sequencing by synthesis. This technique is widely used for metagenomics detection of pathogens in various environmental and clinical samples. Pyrosequencing utilizes enzyme coupled reaction and bioluminescence in combination to monitor the release of pyrophosphate after the addition of a nucleotide in real time. This technique can be potentially applied to sequence a large number of reads in a single run. There are mainly four enzymes required for pyrosequencing: apyrase, luciferase, ATP sulfurylase, and Klenow fragment of DNA polymerase 1 (41). Apyrase is an enzyme incorporated into the process of pyrosequencing for degrading the free nucleotides and ATPs. The reaction mixture of pyrosequencing also demands luciferase, adenosine phosphosulfate, and the DNA template annealed to a primer as a starting material. The recognition and addition of a nucleotide to its complementary base in the single-stranded template leads to release of a pyrophosphate molecule (PPi) and the growth of the DNA strand. This released inorganic pyrophosphate is further converted to ATP in the presence of the enzyme ATP sulfurylase by utilizing the adenosine phosphosulfate molecule as a substrate. Finally, this ATP is utilized by the luciferase enzyme to generate a light signal. This generated light is identified and used as evidence for the incorporation of the nucleotide into the growing chain.
Microalgae II: Cell Structure, Nutrition and Metabolism
Published in Arun Kumar, Jay Shankar Singh, Microalgae in Waste Water Remediation, 2021
After uptake of sulfate ions into the cell, it is either transported to the plastids or stored in the vacuole (only if present in excess). In the plastids, the sulfate ion is first activated by the ATP to produce 5′- adenylsulfate (APS) through the enyme ATP sulfurylase (ATP-S); and then APS is reduced in to sulfite by receiving two electrons from glutathione and the reaction is catalyzed by enzyme APS reductase (Bick and Leustek 1998). Gao et al. (2000) and Koprivova et al. (2000) suggested that APS reductase act as a primary regulation site for the sulfate assimilation pathway in plants and algae. Gao et al. (2000) found remarkable APS reductase activity in some microalgae which may be 400 times more than in the plants; and it mainly depends on microalgal growth rate and the N availability (Gao et al. 2000). Bork et al. (1998) observed that sulfite is further reduced in to sulfide through the enzyme sulfite reductase, which shows structural and functional similarity to nitrite reductase. In the end, this free sulfide is incorporated into cysteine.
Bacterial Synthesis of Metallic Nanoparticles
Published in Ramesh Raliya, Nanoscale Engineering in Agricultural Management, 2019
Shweta Agrawal, Mrinal Kuchlan, Jitendra Panwar, Mahaveer Sharma
The role of these reductases has been elucidated during the formation of ZnSNPs by Rhodobacter sphaeroides. Initially, a soluble sulfate is carried to the interior membrane of R. sphaeroides cell facilitated by the enzyme sulfate permease. The sulfate is then subsequently reduced to sulphite by the enzyme ATP sulfurylase and phosphoadenosine phosphosulfate reductase. The next step in the sequence is the reduction of sulphite to sulphide by the enzyme sulphite reductase. The sulphide reacts with O-acetyl serine in order to synthesize cysteine via O-acetylserine thiolyase, and then cysteine produces S2− by a cysteine desulfhydrase in the presence of zinc. After this process, S2− reacts with the soluble zinc salt and the ZnS NPs are synthesized (Bai et al. 2006, Iravani 2014).
Enhancement of heavy metal tolerance and accumulation efficiency by expressing Arabidopsis ATP sulfurylase gene in alfalfa
Published in International Journal of Phytoremediation, 2019
V. Kumar, S. AlMomin, A. Al-Shatti, H. Al-Aqeel, F. Al-Salameen, A. B. Shajan, S. M. Nair
The metal uptake efficiency of plants has been enhanced through various biotechnological approaches, mainly through introduction of genes that enhance the ability of plants to tolerate/uptake/degrade environmental pollutants (Rugh et al. 1998; Bennett et al. 2003; Van Huysen et al. 2004; Banuelos et al. 2005; Cherian and Oliveira 2005; Doty 2008; Van Aken 2008; Kawahigashi 2009; Pilon-Smits and LeDuc 2009; Van Aken 2009; Nagata et al. 2010; Maestri and Marmiroli 2011; Zhang et al. 2013; Das et al. 2016; Fasani et al. 2018). ATP sulfurylase (APS1) is the first enzyme in the sulfate assimilation pathway of plants, which catalyzes the formation of adenosine phosphosulfate. The APS1 cDNA was cloned from Arabidopsis thaliana (Leustek et al. 1994). APS1 RNA is expressed in all organs of the plant, and the highest transcript abundance and ATP sulfurylase activity were found in leaves or cotyledons (Logan et al. 1996). APS1 is transcriptionally regulated, inducible by sulfate deprivation (Logan et al. 1996), and is upregulated by heavy metal stress (Heiss et al. 1999). Transgenic Indian mustard (Brassica juncea) overexpressing the Arabidopsis APS1 gene demonstrated significantly enhanced ATP sulfurylase activity and selenium accumulation ability (Pilon-Smits et al. 1999; Van Huysen et al. 2004). In addition, the transgenic Indian mustard plants were shown to be more tolerant of six different heavy metals, compared with their wild-type counterparts (Wangeline et al. 2004).
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).