Calcium chloride effects on salinity-induced oxidative stress, proline metabolism and indole alkaloid accumulation in Catharanthus roseus

Catharanthus roseus (L.) G. Don. plants were grown with NaCl and CaCl2 in order to study the effect of CaCl2 on NaCl-induced oxidative stress in terms of lipid peroxidation (TBARS content), H2O2 content, osmolyte concentration, proline (PRO)-metabolizing enzymes, antioxidant enzyme activities, and indole alkaloid accumulation. The plants were treated with solutions of 80 mM NaCl, 80 mM NaCl with 5 mM CaCl2 and 5 mM CaCl2 alone. Groundwater was used for irrigation of control plants. Plants were uprooted randomly on 90 days after sowing (DAS). NaCl-stressed plants showed increased TBARS, H2O2, glycine betaine (GB) and PRO contents, decreased proline oxidase (PROX) activity, and increased gamma-glutamyl kinase (gamma-GK) activity when compared to control. Addition of CaCl2 to NaCl-stressed plants lowered the PRO concentration by increasing the level of PROX and decreasing the gamma-GK activities. Calcium ions increased the GB contents. CaCl2 appears to confer greater osmoprotection by the additive role with NaCl in GB accumulation. The antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were increased under salinity and further enhanced due to CaCl2 treatment. The NaCl-with-CaCl2-treated C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to NaCl-treated and untreated plants.     

Activation of ras signaling pathway by 8-oxoguanine DNA glycosylase bound to its excision product, 8-oxoguanine

8-Oxo-7,8-dihydroguanine (8-oxoG), arguably the most abundant base lesion induced in mammalian genomes by reactive oxygen species, is repaired via the base excision repair pathway that is initiated with the excision of 8-oxoG by OGG1. Here we show that OGG1 binds the 8-oxoG base with high affinity and that the complex then interacts with canonical Ras family GTPases to catalyze replacement of GDP with GTP, thus serving as a guanine nuclear exchange factor. OGG1-mediated activation of Ras leads to phosphorylation of the mitogen-activated kinases MEK1,2/ERK1,2 and increasing downstream gene expression. These studies document for the first time that in addition to its role in repairing oxidized purines, OGG1 has an independent guanine nuclear exchange factor activity when bound to 8-oxoG.     

ETS-1 protein regulates vascular endothelial growth factor-induced matrix metalloproteinase-9 and matrix metalloproteinase-13 expression in human ovarian carcinoma cell line SKOV-3

Matrix metalloproteinase-mediated degradation of extracellular matrix is a crucial event for invasion and metastasis of malignant cells. The expressions of matrix metalloproteinases (MMPs) are regulated by different cytokines and growth factors. VEGF, a potent angiogenic cytokine, induces invasion of ovarian cancer cells through activation of MMPs. Here, we demonstrate that invasion and scattering in SKOV-3 cells were induced by VEGF through the activation of p38 MAPK and PI3K/AKT pathways. VEGF induced the expression of MMP-2, MMP-9, and MMP-13 and hence regulated the metastasis of SKOV-3 ovarian cancer cells, and the activities of these MMPs were reduced after inhibition of PI3K/AKT and p38 MAPK pathways. Interestingly, VEGF induced expression of ETS-1 factor, an important trans-regulator of different MMP genes. ETS-1 bound to both MMP-9 and MMP-13 promoters. Furthermore, VEGF acted through its receptor to perform the said functions. In addition, VEGF-induced MMP-9 and MMP-13 expression and in vitro cell invasion were significantly reduced after knockdown of ETS-1 gene. Again, VEGF-induced MMP-9 and MMP-13 promoter activities were down-regulated in ETS-1 siRNA-transfected cells. VEGF enriched ETS-1 in the nuclear fraction in a dose-dependent manner. VEGF-induced expression of ETS-1 and its nuclear localization were blocked by specific inhibitors of the PI3K and p38 MAPK pathways. Therefore, based on these observations, it is hypothesized that the activation of PI3K/AKT and p38 MAPK by VEGF results in ETS-1 gene expression, which activates MMP-9 and MMP-13, leading to the invasion and scattering of SKOV-3 cells. The study provides a mechanistic insight into the prometastatic functions of VEGF-induced expression of relevant MMPs.     

Novel morpholine ketone analogs as potent histamine H3 receptor inverse agonists with wake activity

Structure-activity relationship on a novel ketone class of H(3)R antagonists/inverse agonists is disclosed. Compound 4 showed excellent target potency, selectivity and brain penetration. Evaluation of antagonist 4 in the rat EEG/EMG model demonstrated robust wake activity thereby establishing preclinical proof of concept.     

Development of micro-shock wave assisted dry particle and fluid jet delivery system

Small quantity of energetic material coated on the inner wall of a polymer tube is proposed as a new method to generate micro-shock waves in the laboratory. These micro-shock waves have been harnessed to develop a novel method of delivering dry particle and liquid jet into the target. We have generated micro-shock waves with the help of reactive explosive compound [high melting explosive (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and traces of aluminium] coated polymer tube, utilising ??9?J of energy. The detonation process is initiated electrically from one end of the tube, while the micro-shock wave followed by the products of detonation escape from the open end of the polymer tube. The energy available at the open end of the polymer tube is used to accelerate tungsten micro-particles coated on the other side of the diaphragm or force a liquid jet out of a small cavity filled with the liquid. The micro-particles deposited on a thin metal diaphragm (typically 100-??m thick) were accelerated to high velocity using micro-shock waves to penetrate the target. Tungsten particles of 0.7???m diameter have been successfully delivered into agarose gel targets of various strengths (0.6?C1.0?%). The device has been tested by delivering micro-particles into potato tuber and Arachis hypogaea Linnaeus (ground nut) stem tissue. Along similar lines, liquid jets of diameter ??200?C250???m (methylene blue, water and oils) have been successfully delivered into agarose gel targets of various strengths. Successful vaccination against murine salmonellosis was demonstrated as a biological application of this device. The penetration depths achieved in the experimental targets are very encouraging to develop a future device for biological and biomedical applications.