Comparison of Myagrum perfoliatum and Sophora alopecuroides in phytoremediation of Cd- and Pb-contaminated soils: A chemical and biological investigation.

Phytoremediation is one of the most cost-effective and environmentally friendly ways to reduce adverse effects of cadmium (Cd) and lead (Pb) in the environment. The present study was conducted to investigate the bioaccumulation factor (BF) and translocation factor (TF) of Cd and Pb in muskweed (Myagrum perfoliatum) and foxtail sophora (Sophora alopecuroides). The impact of contamination on some growth responses of plants and soil biological indicators was also evaluated. A non-contaminated soil sample was divided into several subsamples: one subsample was left as control (without contamination) and the others were separately contaminated with three levels of Cd (3, 5, and 10 mg kg-1) and Pb (100, 300, and 600 mg kg-1). Pot experiments were performed under greenhouse conditions. The BF values of Cd were greater than 1 at all contamination levels indicating the potential of muskweed and foxtail sophora for the uptake and phytostabilization of Cd. The only TF > 1 was obtained for Cd in muskweed grown at the highest Cd contamination level. The TF values of Pb were much lower than those obtained for Cd indicating that Cd was more translocated from root to aerial parts of muskweed and foxtail sophora compared to Pb. The highest contamination levels of Cd and Pb did not significantly affect growth responses of muskweed and foxtail sophora. Furthermore, the cultivation of muskweed and foxtail sophora reduced the impact of Cd and Pb contamination on biological indicators including carbon mineralization ratio (CMR), substrate-induced respiration (SIR), microbial biomass carbon (MBC), and metabolic quotient (qCO2).

Insulin acts at different CNS sites to decrease acute sucrose intake and sucrose self-administration in rats.

Findings from our laboratory and others have demonstrated that the hormone insulin has chronic effects within the CNS to regulate energy homeostasis and to decrease brain reward function. In this study, we compared the acute action of insulin to decrease intake of a palatable food in two different behavioral tasks-progressive ratios sucrose self-administration and micro opioid-stimulated sucrose feeding-when administered into several insulin-receptive sites of the CNS. We tested insulin efficacy within the medial hypothalamic arcuate (ARC) and paraventricular (PVN) nuclei, the nucleus accumbens, and the ventral tegmental area. Administration of insulin at a dose that has no chronic effect on body weight (5 mU) into the ARC significantly suppressed sucrose self-administration (75+/-5% of paired control). However, although the mu opioid DAMGO, [D-Ala2,N-MePhe4,Gly5-ol]-enkephalin acetate salt, stimulated sucrose intake at all four CNS sites, the ventral tegmental area was the only sensitive site for a direct effect of insulin to antagonize acute (60 min) micro opioid-stimulated sucrose feeding: sucrose intake was 53+/-8% of DAMGO-induced feeding, when insulin was coadministered with DAMGO. These findings demonstrate that free feeding of sucrose, and motivated work for sucrose, can be modulated within unique sites of the CNS reward circuitry. Further, they support the interpretation that adiposity signals, such as insulin, can decrease different aspects of ingestion of a palatable food, such as sucrose, in an anatomically specific manner.

Deconstructing the vanilla milkshake: the dominant effect of sucrose on self-administration of nutrient-flavor mixtures.

Rats and humans avidly consume flavored foods that contain sucrose and fat, presumably due to their rewarding qualities. In this study, we hypothesized that the complex mixture of corn oil, sucrose, and flavor is more reinforcing than any of these components alone. We observed a concentration-dependent increase in reinforcers of sucrose solutions received (0%, 3%, 6.25%, and 12.5%) in both fixed ratio and progressive ratio procedures, but with equicaloric corn oil solutions (0%, 1.4%, 2.8%, and 5.6%) this finding was replicated only in the fixed ratio procedure. Likewise, addition of 1.4% oil to 3% or 12.5% sucrose increased fixed ratio, but not progressive ratio, reinforcers received relative to those of sucrose alone. Finally, addition of 3% vanilla flavoring did not change self-administration of 3% sucrose or 3% sucrose+1.4% oil solutions. These data suggest that, calorie-for-calorie, sucrose is the dominant reinforcing component of novel foods that contain a mixture of fat, sucrose, and flavor.