The response to oxidative stress induced by magnesium deficiency in kidney bean plants

To understand the plant response to oxidative stresses, we studied the influence of magnesium (Mg⁺⁺) deficiency on the formation of hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and protease activity in kidney bean plants. The expression pattern of proteins under Mg⁺⁺ deficiency also was examined via two-dimensional electrophoresis. The formation of H₂O₂ and MDA increased in the primary leaves of plants grown in a nutrient solution deficient in Mg⁺⁺. Protease activity in Mg⁺⁺-deficient plants was also higher than in those grown with sufficient Mg⁺⁺. The expression pattern of the proteins showed that 25 new proteins were generated and 64 proteins disappeared under Mg⁺⁺-deficient conditions. Therefore, a deficiency in Mg⁺⁺ may cause oxidative stress and a change in protein expression. Some of these proteins may be related to the oxidative stress induced by Mg⁺⁺ deficiency.     

Identification of a radiosensitivity signature using integrative metaanalysis of published microarray data for NCI-60 cancer cells

ABSTRACT: BACKGROUND: In the postgenome era, a prediction of response to treatment could lead to better dose selection for patients in radiotherapy. To identify a radiosensitive gene signature and elucidate related signaling pathways, four different microarray experiments were reanalyzed before radiotherapy. RESULTS: Radiosensitivity profiling data using clonogenic assay and gene expression profiling data from four published microarray platforms applied to NCI-60 cancer cell panel were used. The survival fraction at 2 Gy (SF2, range from 0 to 1) was calculated as a measure of radiosensitivity and a linear regression model was applied to identify genes or a gene set with a correlation between expression and radiosensitivity (SF2). Radiosensitivity signature genes were identified using significant analysis of microarrays (SAM) and gene set analysis was performed using a global test using linear regression model. Using the radiation-related signaling pathway and identified genes, a genetic network was generated. According to SAM, 31 genes were identified as common to all the microarray platforms and therefore a common radiosensitivity signature. In gene set analysis, functions in the cell cycle, DNA replication, and cell junction, including adherence and gap junctions were related to radiosensitivity. The integrin, VEGF, MAPK, p53, JAK-STAT and Wnt signaling pathways were overrepresented in radiosensitivity. Significant genes including ACTN1, CCND1, HCLS1, ITGB5, PFN2, PTPRC, RAB13, and WAS, which are adhesion-related molecules that were identified by both SAM and gene set analysis, and showed interaction in the genetic network with the integrin signaling pathway. CONCLUSIONS: Integration of four different microarray experiments and gene selection using gene set analysis discovered possible target genes and pathways relevant to radiosensitivity. Our results suggested that the identified genes are candidates for radiosensitivity biomarkers and that integrin signaling via adhesion molecules could be a target for radiosensitization.     

Changes in leptin, ghrelin, growth hormone and neuropeptide-Y after an acute model of MDMA and methamphetamine exposure in rats.

Club drug abuse is a growing problem in the United States. Beyond addiction and toxicity are endocrine effects which are not well characterized. Specifically, the changes in appetite following exposure to drugs of abuse are an interesting but poorly understood phenomenon. Serum hormones such as leptin, ghrelin, growth hormone (GH), and neuropeptide-Y (NP-Y) are known to affect appetite, but have not been studied extensively with drugs of abuse. In this work, we examine the effects of club drugs 3,4-methylenedioxymethamphetamine (MDMA) (ecstasy) and methamphetamine (METH) (doses of 5, 20 and 40 mg/kg) on serum concentrations of these hormones in adult male Sprague-Dawley rats 6, 12, 24 and 48 hours after drug administration. In a dose-dependent manner, MDMA was shown to cause transient significant decreases in serum leptin and GH followed by a base line recovery after 24 hours. Conversely, serum ghrelin increased and normalized after 24 hours. Interestingly, serum NP-Y showed a steady decrease in both treatment of MDMA and METH at different time points and dosages. In humans, abuse of these drugs reduces eating. As evident from these data, acute administration of METH and MDMA had significant effects on different serum hormone levels involved in appetite regulation. Future studies should be performed to see how chronic, low dose drug administration would affect hormone levels and try to answer questions about the physiological mechanisms involved in the anorexic paradigm observed in drug use.     

Specific sequestering agents for the actinides: 10. Enhancement of 238Pu elimination from mice by poly(catechoylamide) ligands

Macromolecules containing four sulfonated catecholy (2,3-dihydroxybenzoyl) groups are effective for decorporation of newly acquired Pu(IV). However, multiple injections in mice and single injections in dogs of 30 mumole/kg of 3,4,3-LICAM(S), the most effective sulfonated poly(catechoylamide) ligand, indicated that it would be toxic, so the ligand structure was modified. Each ligand was injected into mice (30 mumole/kg, intraperitoneally) 1 hr after an intravenous injection of 238Pu(IV) citrate, and mice were killed 24 hr after the Pu injection. Excreta and tissues were analyzed for Pu. (a) The number of catechoyl groups per molecule was reduced to suppress affinity for Fe(III). Net excretion (treated - control) of 55% of the injected Pu was promoted by tetrameric 3,4,3-LICAM(S), 51% by trimeric 3,4-LICAM(S), 22% by dimeric 2-LICAM(S), and 7.4% by the monomer, Tiron. (b) A mesitylene platform was substituted for the linear backbone. Net Pu excretion promoted by MECAM(S), a structurally less flexible trimer, was only 26%, and excretion was delayed. (c) A carboxyl substituent on the catechoyl groups reduced the acidity and hydrophilicity of the ligands. Tetrameric 3,4,3-LICAM(C) promoted 63% net Pu excretion, and one-third of that was fecal. The Pu contents of liver and skeleton were 33 and 44% of their respective 1-hr control values--compared to 51 and 44%, respectively, for CaNa3-DTPA. Mice given 30 mumole/kg of 3,4,3-LICAM(C) 20 times in 4 weeks showed no ill effects. (d) Large N-terminal alkane substituents added to 3,4,3-LICAM(C) increased ligand lipophilicity, hindered Pu chelation, and delayed excretion.     

Erratum to: Rumen-protected conjugated linoleic acid supplementation to dairy cows in late pregnancy and early lactation: effects on milk composition,milk yield,blood metabolites and gene expression in liver

Background  

Conjugated linoleic acid (CLA) is a collective term for isomers of octadecadienoic acid with conjugated double-bond system. Thus, it was the objective to investigate whether milk composition and metabolic key parameters are affected by adding CLA to the diet of dairy cows in the first four weeks of lactation.     

PTC and PROP behave differently in tests of discrimination from their solvents

Better discrimination was possible between phenylthiocarbamide (PTC) solutions and the pure solvent when the solvent was a tasteless low- concentration NaCl solution to which the subject had adapted than when the solvent was purified water. The reverse was true for 6-n- propylthiouracil (PROP). The differences in discrimination for PROP and PTC in the different solvents were caused by differences in the intensity and persistence of aftertastes, rather than a more intense perception of the PTC and PROP tastes per se. This has consequences for traditional approaches to measuring taste sensitivity, as well as indicating that PTC and PROP are not necessarily equivalent indicators of 'taster' versus 'non-taster' status.