Metal phytoremediation potential of naturally growing plants on fly ash dumpsite of Patratu thermal power station,Jharkhand, India

Three naturally growing plants Ipomoea carnea, Lantana camara, and Solanum surattense were found in fly ash dumpsite of Patratu thermal power station, Jharkhand, India. They were assessed for their metal uptake potential. The fly ash was slightly alkaline with very less nitrogen and organic carbon but enriched with phosphorus and heavy metals. Lantana camara and Ipomoea carnea showed good translocation from root to shoot for most of the metals except Mn and Pb. The order of metal accumulation in stem of both the plants were Fe(205mg/kg)>Mn(65mg/kg)>Cu(22.35mg/kg)>Pb(6.6mg/kg)>Cr(3.05mg/kg)>Ni(1 mg/kg)>Cd(0.5 mg/kg) and Fe(741 mg/kg)>Mn(154.05 mg/kg)>Cu(20.75 mg/kg)>Pb(6.75 mg/kg)>Ni(4.0 mg/kg)>Cr(3.3mg/kg)>Cd(0.05mg/kg), respectively. But Solanum surattense accumulated most of the metals in roots. The order was in the following order, Mn (382.2mg/kg) >Fe (264.1mg/kg) > Cu (25.35mg/kg) >Pb (5.95 mg/kg) > Ni (1.9 mg/kg) > Cr (1.8mg/kg) > Cd (0.55 mg/kg). The order of Bioconcentration factor (BCF) in root and shoot followed almost the same order as, Mn>Fe>Ni>Pb>Cu>Cr≈ Cd in all the three species. ANOVA showed significant variation in metal accumulation by root and stem between the species. Finally, it can be concluded that Solanum surattense can be used as phytostabilizer and other two species as phytoextractor of metal for fly ash dumpsite reclamation.     

The tumour suppressor C/EBPδ inhibits FBXW7 expression and promotes mammary tumour metastasis

Inflammation and hypoxia are known to promote the metastatic progression of tumours. The CCAAT/enhancer-binding protein-δ (C/EBPδ, CEBPD) is an inflammatory response gene and candidate tumour suppressor, but its physiological role in tumourigenesis in vivo is unknown. Here, we demonstrate a tumour suppressor function of C/EBPδ using transgenic mice overexpressing the Neu/Her2/ERBB2 proto-oncogene in the mammary gland. Unexpectedly, this study also revealed that C/EBPδ is necessary for efficient tumour metastasis. We show that C/EBPδ is induced by hypoxia in tumours in vivo and in breast tumour cells in vitro, and that C/EBPδ-deficient cells exhibit reduced glycolytic metabolism and cell viability under hypoxia. C/EBPδ supports CXCR4 expression. On the other hand, C/EBPδ directly inhibits expression of the tumour suppressor F-box and WD repeat-domain containing 7 gene (FBXW7, FBW7, AGO, Cdc4), encoding an F-box protein that promotes degradation of the mammalian target of rapamycin (mTOR). Consequently, C/EBPδ enhances mTOR/AKT/S6K1 signalling and augments translation and activity of hypoxia-inducible factor-1α (HIF-1α), which is necessary for hypoxia adaptation. This work provides new insight into the mechanisms by which metastasis-promoting signals are induced specifically under hypoxia.     

Evaluation of comparative effect of pre‐ and posttreatment of selenium on mercury‐induced oxidative stress,histological alterations,and metallothionein mRNA expression in rats

To evaluate the effect of pre‐ or posttreatment of selenium (6 μmol/kg b.w., single intraperitoneal injection) in mercury intoxication, rats were exposed to mercury (12 μmol/kg b.w., single intraperitoneal injection). Exposure to mercury resulted in induced oxidative stress in liver, kidney, and brain tissues. Marked changes in serum biochemical parameters together with alterations in histopathology and an induction in metallothionein‐I and metallothionein‐II mRNA expression in the liver and kidney were observed. Pretreatment with selenium to mercury‐exposed animals had protective effect on the liver, whereas posttreatment had partial protection on restoration of altered oxidative stress parameters. In the kidney, pretreatment with selenium showed partial protection on restoration of altered biochemical parameters, whereas no protection was observed in posttreatment. The pretreatment with selenium resulted in restoration of mercury‐induced metallothionein‐I and metallothionein‐II mRNA expression, which was completely restored in the liver whereas partial restoration was observed in the kidney. Posttreatment with selenium resulted in further induction in metallothionein‐I and metallothionein‐II mRNA expression in the liver and kidney. In the brain, selenium showed partial protection on alerted biochemical parameters. Results indicate that pretreatment with selenium is beneficial in comparison to posttreatment in mercury intoxication. Thus, dietary intake of selenium within safe limit may, therefore, enable us in combating any foreseen effects due to mercury exposure. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:123–135, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20320     

The endophytic fungus Trametes hirsuta as a novel alternative source of podophyllotoxin and related aryl tetralin lignans

The aryl tetralin lignans are synthesized by Podophyllum sps. and are in great demand worldwide due to their use in synthesis of topoisomerase inhibitors. However, the sustained production of these aryl tetralin lignans requires large-scale harvesting from the natural environments, which has resulted in the plant-endangered status. In view of the difficulties in their total chemical synthesis, cultivation and failure of metabolic engineering approaches, there is a need to search for alternative sources of production of aryl tetralin lignans. We unequivocally established the methodology for isolation, identification, and characterization of a novel fungal endophyte (Trametes hirsuta) that produces aryl tetralin lignans consistently as shown by HPLC, LC-MS, LC/MS-MS and (1)H NMR. The lignans produced by the microorganism are biologically active, and exhibit potent antioxidant, anticancer and radioprotective properties. This strategy promises to improve the production of these therapeutically important compounds at lower costs.     

Deciphering the metabolic capabilities of a lipase producing Pseudomonas aeruginosa SL-72 strain

Pseudomonads have been reported for their metabolic, nutritional and ecological versatility, which motivated us to prospect the metabolic profile of a lipolytic strain Pseudomonas aeruginosa SL-72. The strain SL-72 was found to produce high levels of lipase and pectinase (1,555.62?IU/mL and 1,490.33?IU/mL, respectively), esterase and amylase, besides low levels of xylanase, proteinase and cellulase. The strain also tested positive for different plant growth-promoting traits??production of ammonia, hydrogen cyanide, siderophores, phosphate solubilization, nitrate reduction and antifungal activity. The high levels of activity of aryl sulphatase, alkaline phosphatase and fluorescein diacetate hydrolase makes it a useful strain for enhanced nutrient cycling in soil. The strain SL-72 produced rhamnolipids, a biosurfactant and its production was enhanced when starch was used as carbon source (0.256?g/L) and utilized polycyclic hydrocarbon compounds viz. anthracene, phenanthrene, pyrene, fluorene and its mixture. The multifaceted nature of the culture illustrates its promise in bioremediation, industry, besides its use as an inoculant.