Mouse Anti-Human GST Hybridoma [GST-1941]

Heavy metal pollution seriously impairs crop production and poses serious concerns for human health. Exogenous application of biomolecules has been efficiently tested for enhancing plant resistance to metal toxicity. Current study evaluates the possible effect of 5-aminolevulinic acid (ALA) in Brassica juncea L. seedlings subjected to lead (Pb) stress. Our results showed that shoot length, root length and chlorophyll contents were significantly recovered in Pb stressed seedlings after ALA application, accompanied by reduction in the Pb accumulation. Significant reduction in the contents of reactive oxygen species (ROS) like superoxide anion, hydrogen peroxide and malondialdehyde were also observed in ALA treated seedlings under Pb stress. Furthermore, we also noticed enhancement in the activities of antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), glutathione reductase (GR), glutathione-S-transferase (GST) and dehydroascorbate reductase (DHAR). We further noticed that ALA upregulated the expression of SOD (7.30 folds), POD (6.11 folds), CAT (3.52 folds), DHAR (6.42 folds), GR (6.04 folds), and GST (5.58 folds) under the Pb stress. However, RBOH1 (gene involved in ROS generation) and CHLASE (chlorophyllase) expressions were reduced in ALA treated seedlings grown under Pb stress (RBOH1 expression decreased to 3.44 from 6.50 fold and CHLASE expression decreased to 2.97 from 5.58 fold). Phenolic contents were increased in the presence of ALA and expression of genes like CHS (chalcone synthase; 7.50 fold) and PAL (phenylalanine ammonia lyase; 4.77 fold) was also stimulated by ALA under Pb stress. Furthermore, contents of the Krebs cycle metabolites (fumarate, succinate, malate and citrate) were also enhanced accompanied by upregulated expression of genes like CS (citrate Synthase; 8.13 fold), SUCLG1 (succinyl CoA ligase 1; 7.40 fold), SDH (succinate dehydrogenase; 5.10 fold) and FH (fumarate hydratase; 5.65 fold). In conclusion, current investigation revealed that ALA attenuated Pb toxicity by modulating the transcription patterns of key enzymes involved in plant defense system.

The genusXanthomonascomprises several cosmopolitan plant-pathogenic bacteria that affect more than 400 plant species, most of which are of economic interest. Citrus canker is a bacterial disease that affects citrus species, reducing fruit yield and quality, and is caused by the bacteriumXanthomonas citrisubsp.citri(Xac). The Xac3819 gene, which has previously been reported to be important for citrus canker infection, encodes an uncharacterized glutathioneS-transferase (GST) of 207 amino-acid residues in length (XacGST). Bacterial GSTs are implicated in a variety of metabolic processes such as protection against chemical and oxidative stresses. XacGST shares high sequence identity (45%) with the GstB dehalogenase fromEscherichia coliO6:H1 strain CFT073 (EcGstB). Here, XacGST is reported to be able to conjugate glutathione (GSH) with bromoacetate with aK(m)of 6.67 +/- 0.77 mM, ak(cat)of 42.69 +/- 0.32 s(-1)and a k(cat)/K(m)of 6.40 +/- 0.72 mM(-1) s(-1)under a saturated GSH concentration (3.6 mM). These values are comparable to those previously reported for EcGstB. In addition, crystal structures of XacGST were determined in the apo form (PDB entry6nxv) and in a GSH-bound complex (PDB entry6nv6). XacGST has a canonical GST-like fold with a conserved serine residue (Ser12) at the GSH-binding site near the N-terminus, indicating XacGST to be a serine-type GST that probably belongs to the theta-class GSTs. GSH binding stabilizes a loop of about 20 residues containing a helix that is disordered in the apo XacGST structure.