Power System State Estimation using Microsoft Excel

This paper presents the design and development of a Microsoft Excel based tool for Power System Static State Estimation. This tool can be effectively used to understand the process of state estimation and its real-time application. The tool contains Newton-Raphson load flow that provides system measurements, which are used as inputs to the state estimator that uses the popular weighted least square (WLS) algorithm. The spreadsheet has features for corrupting the data to simulate wide ranging scenarios of data errors. With the user-friendly screens, this can be a versatile desktop tool for learning and experimenting with the Power System State Estimation. Different system loading and operating configurations and wide range of corrupted measurements can be simulated for obtaining the reliable state estimator. All intermediate numerical results are made available for verification purposes. For illustration IEEE 14 bus system is considered

Over-expression of Topoisomerase II Enhances Salt Stress Tolerance in Tobacco

Topoisomerases are unique enzymes having an ability to remove or add DNA supercoils and untangle the snarled DNA. They can cut, shuffle and religate DNA strands and remove the torsional stress during DNA replication, transcription or recombination events. In the present study, we over-expressed topoisomerase II (TopoII) in tobacco (Nicotiana tabaccum) and examined its role in growth and development as well as salt (NaCl) stress tolerance. Several putative transgenic plants were generated and the transgene integration and expression was confirmed by PCR and Southern blot analyses, and RT-PCR analysis respectively. Percent seed germination, shoot growth and chlorophyll content revealed that transgenic lines over-expressing the NtTopoIIα-1 gene exhibited enhanced tolerance to salt (150 and 200 mM NaCl) stress. Moreover, over-expression of TopoII lead to the elevation in proline and glycine betaine levels in response to both concentrations of NaCl as compared to wild-type. In response to NaCl stress, TopoII over-expressing lines showed reduced lipid peroxidation derived malondialdehyde (MDA) generation. These results suggest that TopoII plays a pivotal role in salt stress tolerance in plants

Characterization of phoA, a Bacterial Alkaline Phosphatase for Phi Use Efficiency in Rice Plant

Fertilizers and herbicides are two major components in the agriculture system for achieving crop productivity. Massive use of orthophosphate fertilizers and herbicides poses threats to phosphate reserves and aids the evolution of herbicide tolerant weed biotypes. Phosphite (Phi), a phosphate analog, has been proposed as more beneficial than traditionally used phosphate fertilizers and herbicides in the agriculture. We developed phoA overexpressing transgenic rice that minimizes the phosphate loss and contributes to weed management in the agriculture. The phoA rice lines showed improved root, shoot length and total biomass production under phosphite conditions. Additionally, the complete phenotype and productivity of phoA lines under the phosphite treatment attained was similar to that of plants under phosphate sufficient condition. The Phi metabolizing properties of the phoA overexpressed lines improved under the Phi application and phi treatment enabled controlling of weeds without compromising the yield of transgenic rice plants. Our results indicated that phoA alone or in combination with other Phi metabolizing gene(s) can possibly be used as an effective ameliorating system for improving crop plants for phi-based fertilization and weed management strategy in the agriculture

Transcriptional Downregulation of Rice rpL32 Gene under Abiotic Stress Is Associated with Removal of Transcription Factors within the Promoter Region

Background: The regulation of ribosomal proteins in plants under stress conditions has not been well studied. Although a few reports have shown stress-specific post-transcriptional and translational mechanisms involved in downregulation of ribosomal proteins yet stress-responsive transcriptional regulation of ribosomal proteins is largely unknown in plants. Methodology/Principal Findings: In the present work, transcriptional regulation of genes encoding rice 60S ribosomal protein L32 (rpL32) in response to salt stress has been studied. Northern and RT-PCR analyses showed a significant downregulation of rpL32 transcripts under abiotic stress conditions in rice. Of the four rpL32 genes in rice genome, the gene on chromosome 8 (rpL32_8.1) showed a higher degree of stress-responsive downregulation in salt sensitive rice variety than in tolerant one and its expression reverted to its original level upon withdrawal of stress. The nuclear run-on and promoter:reporter assays revealed that the downregulation of this gene is transcriptional and originates within the promoter region. Using in vivo footprinting and electrophoretic mobility shift assay (EMSA), cis-elements in the promoter of rpL32_8.1 showing reduced binding to proteins in shoots of salt stressed rice seedlings were identified. Conclusions: The present work is one of the few reports on study of stress downregulated genes. The data revealed that rpL32 gene is transcriptionally downregulated under abiotic stress in rice and that this transcriptional downregulation i

Glutathione Peroxidase of <i>Pennisetum glaucum</i> (PgGPx) Is a Functional Cd²⁺ Dependent Peroxiredoxin that Enhances Tolerance against Salinity and Drought Stress

<div><p>Reactive oxygen species (ROS) arise in the plant system due to inevitable influence of various environmental stimuli. Glutathione peroxidases are one of the important ROS scavengers inside the cell. A glutathione peroxidase (<i>PgGPx</i>) gene was previously found from <i>Pennisetum glauccum</i> abiotic stressed cDNA library. Enzyme kinetics data revealed that PgGPx possessed preference towards thioredoxin rather than glutathione as electron donor and thus belongs to the functional peroxiredoxin group. Moreover, its activity was found to be dependent on divalent cations, especially Cd²⁺ and homology model showed the presence of Cd²⁺ binding site in the protein. Site directed mutagenesis study of PgGPx protein revealed the vital role of two conserved Cysteine residues for its enzymatic activity and structural folding. Expression analysis suggested that <i>PgGPx</i> transcript is highly up-regulated in response to salinity and drought stresses. When expressed ectopically, <i>PgGPx</i> showed enhanced tolerance against multiple abiotic stresses in prokaryotic <i>E</i>. <i>coli</i> and model plant, rice. Transgenic rice plants showed lesser accumulation of MDA and H₂O₂; and higher accumulation of proline as compared to wild type (WT) plants in response to both salinity and drought stresses that clearly indicates suppression of lipid peroxidation and ROS generation in transgenic lines. Moreover, transgenic plants maintained better photosynthesis efficiency and higher level of antioxidant enzyme activity as compared to WT plants under stress conditions. These results clearly indicate the imperative role of PgGPx in cellular redox homeostasis under stress conditions, leading to the maintenance of membrane integrity and increased tolerance towards oxidative stress.</p></div

Confirmation of the ectopically expressed <i>PgGPx</i> transgenic rice plants and their stress tolerance potential.

<p>(A) Schematic illustration of the pMDC99-PgGPx expression vector used to overexpress <i>PgGPx</i> in rice plants. Putative transgenic lines were initially screened by PCR using <i>PgGPx</i> gene specific primers (B) and further confirmed by Southern blot analysis using full length <i>PgGPx</i> cDNA as probe (C). To evaluate the expression of <i>PgGPx</i> transcript in the 14 days old WT and five single copy T₁ transgenic lines (L-1, L-3, L-6, L-8 and L-10) under normal condition, Reverse transcription PCR (RT-PCR) was carried out (D) and compared with house keeping gene, <i>Tubulin</i>. (E) Total glutathione peroxidase activity was determined from WT and transgenic plants (L-1, L-3, L-6, L-8 and L-10). Rapid leaf strips senescence assay of transgenic vis-a-vis WT plants was performed, to assess the stress tolerance under 200 mM NaCl or 150 mM mannitol. Leaf strips floated on water served as the experimental control (G). Total chlorophyll contents were estimated from the corresponding control, salt and mannitol treated leaf strips of WT as well as transgenic lines. The data represent means±standard deviation (STD) of three biological replicates (n = 3). Statistically significant differences were determined using two-tailed paired Student’s t-test as compared with WT plants of similar conditions and indicated by ^a,P < 0.001 or ^b,P < 0.01 or ^c,P < 0.05.</p

Transgenic tobacco expressing Entamoeba histolytica calcium binding protein exhibits enhanced growth and tolerance to salt stress

Calcium has been recognized as an important signal in many abiotic stresses. Our earlier work indicated the presence of homologues of a novel calcium binding protein from Entamoeba histolytica (EhCaBP) and its binding proteins with kinase activity in different plants. In this paper, we demonstrate the transfer of EhCaBP cDNA into tobacco via Agrobacterium mediated transformation. The transgenic plants expressing EhCaBP proteins were identified using western blots and immuno-precipitation of the labeled EhCaBP protein. The seeds obtained from the transgenic plants exhibited enhanced rate of germination and increased growth and had 20-37% more dry weight in 3 weeks old seedlings compared to wild type controls. The seeds of transgenic plants were also able to germinate and grow on 200 mM NaCl. The dry weight of different EhCaBP expressing plants maintained on NaCl was 55-100% more as compared to wild type plants. The increased growth and tolerance to salinity conditions were correlated with the expression of EhCaBP protein in the transgenic plants

A high-throughput genome-walking method and its use for cloning unknown flanking sequences

We developed a PCR-based high-throughput genome-walking protocol. The novelty of this protocol is in the random introduction of unique walker primer binding sites into different regions of the genome efficiently by taking advantage of the rolling circle mode of DNA synthesis by Phi29 DNA polymerase after annealing the partially degenerate primers to the denatured genomic DNA. The inherent strand-displacement activity of the Phi29 DNA polymerase displaces the 5' ends of downstream strands and DNA synthesis continues, resulting in a large number of overlapping fragments that cover the whole genome with the unique walker adapter attached to the 5' end of all the genomic DNA fragments. The directional genome walking can be performed using a locus-specific primer and the walker primer and Phi29 DNA polymerase-amplified genomic DNA fragments as template. The locus-specific primer will determine the position and direction of the genome walk. Two rounds of successive PCR amplifications by locus-specific and walker primers and their corresponding nested primers effectively amplify the flanking DNA fragments. The desired PCR fragment can be either cloned or sequenced directly using another nested, locus-specific primer. We successfully used this protocol to isolate and sequence 5' flanking regions/promoters of selected plant genes