The function and evolution of the response regulator CtrA in Rhodobacter capsulatus and Alphaproteobacteria

Rhodobacter capsulatus is a model organism for studying gene transfer agents (GTAs). GTAs are a unique facilitator of gene transfer in prokaryotes. The DNA binding response regulator CtrA plays a key role in modulating GTA activity in R. capsulatus, as well as flagellar biosynthesis and cell motility. CtrA is an OmpR/PhoB response regulator with an N-terminal receiver domain and a C-terminal transcriptional regulator domain. One unusual aspect of CtrA function in R. capsulatus is that it regulates gene expression in both the phosphorylated and nonphosphorylated forms. Using overlap extension PCR, the constructs for expression of three of different versions of ctrA in R. capsulatus were prepared: wild type, phosphomimetic, nonphosphorylatable. These constructs place the genes under the control of the R. capsulatus puf promoter for high level of expression and the encoded proteins have 6×-histidine tags for purification in studies aimed at determination of the DNA binding sites of the different versions of CtrA. Horizontal gene transfer is an interesting way that bacteria can increase their genetic diversity. In this work, the distribution of ctrA in the Alphaproteobacteria was examined and evidence of horizontal gene transfer of this gene was found. Using phylogenetic analyses, several instances of apparent misclassification of alphaproteobacteria to the wrong orders were found and one candidate ctrA horizontal gene transfer event that may have occurred in an ancestral bacterium that subsequently evolved into one lineage within the order Sphingomonadales was found

Investigation of the treatment of epilepsy with cannabinoids

Cannabis has been consumed by humans for millennia, and is currently used in Canada for the treatment of a variety of medical conditions including anxiety, PTSD, and chronic pain. The medical community is hesitant to accept the use of Cannabis and cannabinoids to treat epilepsy due to inadequate information on mechanism of action and long-term effects. Cannabidiol (CBD) is approved to treat pediatric patients with severe epilepsies such as Dravet Syndrome and Lennox-Gastaut Syndrome in the US and some European countries, but there are many individuals with less severe epilepsies whose quality of life is affected by negative side-effects from current anti-epileptic drugs. This research aims to globally evaluate which of the 6 most prevalent cannabinoids show seizure reduction and to investigate the mechanism of action of cannabinoids in an epilepsy model. Using a chemical model of epilepsy, zebrafish larvae were treated with phytocannabinoids, and their seizures measured through an optimized behaviour tracking method. Unique to this study, cannabinoid uptake was measured in larvae with a novel HPLC method developed in this project. This accomplishment is superior to previous attempts to quantify cannabinoid uptake by measuring losses in the water used to deliver cannabinoid to fish, which assumes that all losses are due to uptake and metabolism by the study organisms. CBD induced seizure reduction is partially mediated by the Gprotein coupled receptor GPR55 and potentially through CB1R. Treatment with cannabinol (CBN) and cannabichromene (CBC) decreased seizure intensity at lower concentrations than CBD. Δ9-tetrahydrocannabinol (Δ9-THC), Δ8-tetrahydrocannabinol (Δ8-THC), and cannabigerol (CBG) only showed antiepileptic effects at a high concentration, but when concentrationd in combination with CBD reduced seizures more than either treatment alone. RT-qPCR showed changes in expression of endocannabinoid system (napepld, gde1, faah, ptgs1, ptgs2a) and neural (fosab, pyya) genes in response to phytocannabinoid treatment. The data reported in this thesis supports the hypothesis that phytocannabinoids are promising anti-epileptics and could be used in combination therapies for more effective seizure relief

Adaptive hysteresis band current control of grid connected PV inverter

In this paper, adaptive hysteresis band current controller is implemented to control the current injected into the grid. Initially it was implemented by B.K Bose for control of the machine drive. Now it is implemented for the grid connected PV inverter, to control the current injected into Grid. It is well suitable for the distribution generation. The adaptive hysteresis band controller changes the bandwidth based on the modulating frequency, supply voltage, input DC voltage and slope of the reference current. Consequently, the controller generates pulses to the inverter. It is advantageous over the conventional hysteresis controller, as the switching frequency is maintained almost constant. Thereby quality of grid current is also improved. It is verified in time domain analysis of simulation using MATLAB

Importance of ROS and antioxidant system during the beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation

The present study suggests the importance of reactive oxygen species (ROS) and antioxidant metabolites as biochemical signals during the beneficial interactions of mitochondrial metabolism with photosynthetic carbon assimilation at saturating light and optimal CO2. Changes in steady-state photosynthesis of pea mesophyll protoplasts monitored in the presence of antimycin A [AA, inhibitor of cytochrome oxidase (COX) pathway] and salicylhydroxamic acid [SHAM, inhibitor of alternative oxidase (AOX) pathway] were correlated with total cellular ROS and its scavenging system. Along with superoxide dismutase (SOD) and catalase (CAT), responses of enzymatic components-ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), glutathione reductase (GR) and non-enzymatic redox components of ascorbate-glutathione (Asc-GSH) cycle, which play a significant role in scavenging cellular ROS, were examined in the presence of mitochondrial inhibitors. Both AA and SHAM caused marked reduction in photosynthetic carbon assimilation with concomitant rise in total cellular ROS. Restriction of electron transport through COX or AOX pathway had differential effect on ROS generating (SOD), ROS scavenging (CAT and APX) and antioxidant (Asc and GSH) regenerating (MDAR and GR) enzymes. Further, restriction of mitochondrial electron transport decreased redox ratios of both Asc and GSH. However, while decrease in redox ratio of Asc was more prominent in the presence of SHAM in light compared with dark, decrease in redox ratio of GSH was similar in both dark and light. These results suggest that the maintenance of cellular ROS at optimal levels is a prerequisite to sustain high photosynthetic rates which in turn is regulated by respiratory capacities of COX and AOX pathways

DEVELOPMENT OF OSMOTICALLY CONTROLLED ORAL DRUG DELIVERY SYSTEM FOR NATEGLINIDE AN ANTI-DIABETIC DRUG

Objective: The purpose of the present study was to develop an oral push-pull osmotic drug delivery system for the drug Nateglinide which is a bio pharmaceutics classification system (BCS) class II drug. Methods: The tablets were prepared by the wet granulation method using ingredients microcrystalline cellulose (Adsorbent), potassium chloride (Osmotic agent), poly ethylene glycol (4000 and 6000) (Hydrophilic polymer, Plasticizer), starch (Disintegrant), and aerosil. The granules were compacted by double compression method and were coated with eudragit by dipping method. Different batches were prepared to study the effect of the various ingredients and their effect on the release of the drug from the system by varying the concentrations of the ingredients in each batch. Dissolution was assessed using USP dissolution apparatus 2 in phosphate buffer pH 6.8 for 12 h. Results: Certain key findings observed includes a decrease in micro crystalline cellulose content reduced the release of the drug due to the reduction of the hydrophilic content in the tablet which complements the uptake of water from the surroundings, and increase in the ethylene glycol leads to decrease in the release which resulted due to excess swelling and increase in the osmotic agent concentration lead to satisfactory release of the drug and followed zero-order release. Conclusion: To conclude, the push-pull osmotic tablet of Nateglinide was able to deliver the drug in a controlled pattern for a prolonged period of time. This type of formulation can be used in conditions like hyperglycemia where the patient compliance can improve by reducing the dosing frequency and the plasma drug levels can be maintained, the total drug load is also reduced so that the dose related side-effects are also reduced. Keywords: Controlled release, Push-pull osmotic pump, Nateglinid

Neutral and cationic half-sandwich arene ruthenium, Cp*Rh and Cp*Ir oximato and oxime complexes: Synthesis, structural, DFT and biological studies

The reaction of [(p-cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) with chelating ligand 2-pyridylcyanoxime {pyC(CN)NOH} leads to the formation of neutral oximato complexes having the general formula [(arene)M{pyC(CN)NO}Cl] {arene = p-cymene, M = Ru, (1); Cp*, M = Rh (2);Cp*, M = Ir (3)}. Whereas the reaction of 2-pyridyl phenyloxime {pyC(Ph)NOH} and 2-thiazolyl methyloxime {tzC(Me)NOH} with precursor compounds afforded the cationic oxide complexes bearing formula [(arene)M{pyC(ph)NOH}Cl]+ and [(arene)M{tzC(Me)NOH}Cl]+{arene = p-cymene M = Ru, (4), (7); Cp*, M = Rh (5), (8); Cp*, M = Ir (6), (9)}. The cationic complexes were isolated as their hexafluorophosphate salts. All these complexes were fully characterized by analytical, spectroscopic and X-ray diffraction studies. The molecular structures of the complexes revealed typical piano stool geometry around the metal center within which the ligand acts as a NNʹ donor chelating ligand. The Chemo-sensitivity activities of the complexes evaluated against HT-29 (human colorectal cancer), and MIAPaCa-2 (human pancreatic cancer) cell line showed that the iridium-based complexes are much more potent than the ruthenium and rhodium analogues. Theoretical studies were carried out to have a deeper understanding about the charge distribution pattern and the various electronic transitions occurring in the complexes

Time Domain Explorations With Digital Sky Surveys

One of the new frontiers of astronomical research is the exploration of time variability on the sky at different wavelengths and flux levels. We have carried out a pilot project using DPOSS data to study strong variables and transients, and are now extending it to the new Palomar-QUEST synoptic sky survey. We report on our early findings and outline the methodology to be implemented in preparation for a real-time transient detection pipeline. In addition to large numbers of known types of highly variable sources (e.g., SNe, CVs, OVV QSOs, etc.), we expect to find numerous transients whose nature may be established by a rapid follow-up. Whereas we will make all detected variables publicly available through the web, we anticipate that email alerts would be issued in the real time for a subset of events deemed to be the most interesting. This real-time process entails many challenges, in an effort to maintain a high completeness while keeping the contamination low. We will utilize distributed Grid services developed by the GRIST project, and implement a variety of advanced statistical and machine learning techniques.Comment: 5 pages, 2 postscript figures, uses adassconf.sty. To be published in: "ADASS XIV (2004)", Eds. Patrick Shopbell, Matthew Britton and Rick Ebert, ASP Conference Serie

Protease inhibitors of Cajanus conferring resistance to pod borer of pigeonpea (Cajanus cajan L. Millsp.).

Pigeonpea is susceptible to pod borer damage with resistance lacking in its primary gene pool. Many Cajanus species harbor high levels of resistance. Host plant resistance can play an important role in minimizing the extent of losses due to insects and pests as well as the use of insecticides/pesticides and thus protect the environment. A major initiative was undertaken to tap the defence genes from wild relatives of secondary and tertiary gene pool through wide hybridization and thereby introgress resistance to pod borer. A range of interspecific derivatives derived from C. lanceolatus, C. cajanifolius, C. volubilis and C. platycarpus along with their parents were screened for the pod borer resistance under unprotected field conditions at ICRISAT, Patancheru, India. Biochemical basis of resistance was also identified by studying the levels of defence proteins active against bovine pancreatic trypsin, chymotrypsin and trypsin-like enzymes of H. armigera mid-gut proteases. Protease inhibitor profiles of parents and interspecific derivatives differed in terms of activity units, number and intensities of activity bands visualized on gelatin-PAGE. As the protease inhibitors are anti-nutritional factors, parents and interspecific derivatives, which resulted in high levels of Helicoverpa gut protease inhibitor (HGPI) units were screened for Human pancreatic trypsin inhibitor (HPTI) activity levels. Samples with high ratio of HGPI/HPTI represent less or no effect on human pancreatic trypsin and high effect on insect gut proteases

The SPLASH Survey: A Spectroscopic Portrait of Andromeda's Giant Southern Stream

The giant southern stream (GSS) is the most prominent tidal debris feature in M31's stellar halo. The GSS is composed of a relatively metal-rich, high surface-brightness "core" and a lower metallicity, lower surface brightness "envelope." We present Keck/DEIMOS spectroscopy of red giant stars in six fields in the vicinity of M31's GSS and one field on Stream C, an arc-like feature on M31's SE minor axis at R=60 kpc. Several GSS-related findings and measurements are presented here. We present the innermost kinematical detection of the GSS core to date (R=17 kpc). This field also contains the continuation of a second kinematically cold component originally seen in a GSS core field at R=21 kpc. The velocity gradients of the GSS and the second component in the combined data set are parallel over a radial range of 7 kpc, suggesting a possible bifurcation in the line-of-sight velocities of GSS stars. We also present the first kinematical detection of substructure in the GSS envelope. Using kinematically identified samples, we show that the envelope debris has a ~0.7 dex lower mean photometric metallicity and possibly higher intrinsic velocity dispersion than the GSS core. The GSS is also identified in the field of the M31 dSph satellite And I; the GSS in this field has a metallicity distribution identical to that of the GSS core. We confirm the presence of two kinematically cold components in Stream C, and measure intrinsic velocity dispersions of ~10 and ~4 km/s. This compilation of the kinematical (mean velocity, intrinsic velocity dispersion) and chemical properties of stars in the GSS core and envelope, coupled with published surface brightness measurements and wide-area star-count maps, will improve constraints on the orbit and internal structure of the dwarf satellite progenitor.Comment: Accepted for publication in Ap