A Mutation in the Arabidopsis KT2/KUP2 Potassium Transporter Gene Affects Shoot Cell Expansion

Potassium ions (K+) are the most abundant cations in plants and are necessary for cell growth. Arabidopsis shy3-1 mutant plants have a short hypocotyl, small leaves, and a short flowering stem, and these defects result from decreased cell expansion. The semidominant shy3-1 mutation changes an amino acid in KT2/KUP2, a K+ transporter related to the Escherichia coli Kup protein. Second mutations in the KT2/KUP2/SHY3 gene, including presumed null mutations, suppress the shy3-1 phenotypes. Plants with these intragenic suppressor mutations appear similar to wild-type plants, suggesting that KT2/KUP2/SHY3 acts redundantly with other genes. Expression of the shy3-1 mutant version of KT2/KUP2/SHY3 in wild-type plants confers shy3-1–like phenotypes, indicating that shy3-1 probably either causes a gain of function or creates an interfering protein. The shy3-1 mutation does not eliminate the ability of the KT2/KUP2 cDNA to rescue the growth of a potassium transport-deficient E. coli mutant. A PSHY3::GUS fusion is expressed in growing portions of the plant. These results suggest that KT2/KUP2/SHY3 mediates K+-dependent cell expansion in growing tissues

Evidences for Extreme Wave Events in Velanganni Coast, Southeast of India

The present study focuses on sediment grain size, microfossil content and heavy minerals present in the sediments collected from a trench in the southeast coast of India in order to identify the frequent extreme wave events (e.g. storm surge, cyclone, tsunami, etc.). Two different depositional events were identified at different depths with distinct sedimentological, mineralogical and microfossil characteristics. These geological features further improve the understanding of depositional sequences in this region

Isolation, Identification, Morphological Studies and Lipid Granules Staining (Nile red) of Different Micro-Algae for Biodiesel Production from Fresh Water and Saline Water

In the present study, the algal samples were collected from temple tanks, saline water in Chennai, Mahapaliburam and Kovallam. Collections were carried out during the month of September 2010 and February 2011. Samples were studied in the laboratory and identified. In their surveyed the population, identification, morphological, and examined the Nile red method with microalgae genus of various classes. Various physical and chemical treatments were applied to the existing Nile red method to improve the effectiveness and efficiency. The following algae were present Chlorella vulgaris, Nannnochloropsis, Dunaliella tertiolecta, Tetraselmis suecica, Chlorococcum humicolo, Scenedesmus acuminatus, Amphora coffeaformis, and Nitzschia longissima. Algae are described with photographs

PHYTOCHEMICAL SCREENING, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF MILLINGTONIA HORTENSIS (L)

Objective: Millingtonia hortensis Linn (Bignoniaceae) is commonly known as cork tree and Akash neem. Aim of studies to determine the antioxidant activity and antibacterial activity.Methods: The antioxidant activity of different solvent extracts were measured by chemical analyses involving the assay of 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity and super oxide radical scavenging activity.Results: Phytochemicals (secondary metabolites) screening of methanol, chloroform, ethanol, petroleum ether, aqueous leaf extracts revealed the presence of carbohydrates, tannins, saponins, flavonoids, alkaloids, betacyanins, phenols and coumarins.Conclusion: The presence of these phytochemicals and antioxidant capacity support the use of this plant as an antibacterial agent against the group of micro organisms tested.Â

Absorption Spectroscopic Studies of Chip-scale Rubidium Atomic Vapour Cells in a Compact 3D Printed Magneto-Optic Package

This paper describes the design, development and spectroscopic studies of chip-scale Rb atomic vapour cell developed in the authors’ laboratory. A compact magneto-optic package for the chip-scale Rb cell comprising of TEC integrated VCSEL source, silicon p-i-n photo detector and a hemispherical lens for light collimation is reported. The package is manufactured using commercial 3D printing technology. A PC based data acquisition system has been developed to provide real time analysis of the captured spectral data of the Rb chip by laser interrogation of the D1 hyperfine transition. Doppler broadened absorption resonance lines of technological importance have been recorded for transitions 85Rb(2S1/2 F=2→2P1/2 F′ =2,3) having absorption amplitude 1.24 V and FWHM 850 MHz and 87Rb(2S1/2 F=2 →2P1/2 F′ =1,2) has absorption amplitude 0.47 V and FWHM 567 MHz at cell temperature of 70 oC . Further, the chip-scale Rb atomic cell in the magneto-optical package will be explored to develop atomic sensors for space applications

Bactericidal activity of biosynthesized silver nanoparticles against human pathogenic bacteria

Green synthesis is an attractive and eco-friendly approach to generate potent antibacterial silver nanoparticles (Ag-NPs). Such particles have long been used to fight bacteria and represent a promising tool to overcome the emergence of antibiotic-resistant bacteria. In this study, green synthesis of Ag-NPs was attempted using plant extracts of Aloe vera, Portulaca oleracea and Cynodon dactylon. The identity and size of Ag-NPs was characterized by ultraviolet–visible spectrophotometer and scanning electron microscopy. Monodispersed Ag-NPs were produced with a range of different sizes based on the plant extract used. The bactericidal activity of Ag-NPs against a number of human pathogenic bacteria was determined using the disc diffusion method. The results showed that Gram positive bacteria were more susceptible than Gram negative ones to these antibacterial agents. The minimum inhibitory concentration was determined using the 96-well plate method. Finally, the mechanism by which Ag-NPs affect bacteria was investigated by SEM analysis. Bacteria treated with Ag-NPs were seen to undergo shrinkage and to lose their viability. This study provides evidence for a cheap and effective method for synthesizing potent bactericidal Ag-NPs and demonstrates their effectiveness against human pathogenic bacteria

W-shaped chirp free and chirped bright, dark solitons for perturbed nonlinear Schrödinger equation in nonlinear optical fibers

In the present investigation, we employed the Jacobi elliptic function (JEF) method to invoke the perturbed nonlinear Schrödinger equation with self-steepening (SS), self-phase modulation (SPM), and group velocity dispersion (GVD), which govern the propagation of solitonic pulses in optical fibres. The proposed algorithm proves the existence of the family of solitons in optical fibers. Consequently, chirped and chirp free W-shaped bright, dark soliton solutions are obtained from dn(ξ), cn(ξ) and sn(ξ) functions. The final results are displayed in three-dimensional plots with specific physical values of GVD, SPM and SS for an optical fiber

Parametric Study of CPT Resonance in Rubidium Vapor Cell for Application in Atomic Clock

The performance of Coherent Population Trapping (CPT) based atomic clocks primarily depends on the characteristics of CPT resonance. We have performed experiments to study and optimize the characteristics of CPT resonance in 87Rb atoms by measuring its contrast and full-width-at-half maximum (FWHM) as function of laser excitation and temperature of atomic vapor cells with different dimensions. A four-level atomic model is used to simulate CPT resonance characteristics along the length of atomic vapor cell. The model incorporates scaling law to understand collision dynamics in cells with different radius for a range of laser excitation intensities and the results are compared with experimental data. The quality figure, calculated from the measured values of FWHM and contrast, decreases with increase in laser intensity and improves in cells with higher dimension (radius). The optimum temperature corresponding to maximum quality figure varies with laser excitation intensity as well as cell dimension. The underlying collision dynamics and density effects that are responsible for the observed resonance characteristics are discussed