In Vitro Anti Bacterial Potential of Different Extracts of Tagetes Erecta and Tagetes Patula

The antimicrobial activity of cold aqueous, hot aqueous and methanol extracts of Tagetes erecta and Tagetes patula flowers was evaluated by agar well diffusion method against ten different pathogenic species of Gram-negative bacteria viz.,  Escherichia coli, Proteus vulgaris, Proteus mirabilis, Aeromonas sobria, Aeromonas hydrophila, Plesiomonas shigelloides, Salmonella enterica serotype Typhi, Salmonella enterica serotype Typhimurium, Salmonella enterica serotype Aboni and Salmonella enterica serotype Enteritidis, four different pathogenic species of Gram-positive bacteria such as Bacillus subtilis, Bacillus cereus, Bacillus circulans and Staphylococcus aureus. Methanol extract of Tagetes erecta at 40 mg/ml concentration was found to have better inhibitory activity when compared to cold and hot aqueous extracts, which were evident through the increased zones of inhibition against Gram-negative and Gram-positive bacteria. Methanol extract of Tagetes erecta showed highest inhibition zone of 26 mm against Aeromonas sorbia, Aeromonas hydrophila, Staphylococcus aureus (MTCC7405) and Staphylococcus aureus (clinical isolate), while lowest inhibition zone of 12 mm with Bacillus subtilis. Similarly, hot aqueous extracts of Tagetes patula had better activity as compare to cold aqueous extract and methanol extract at 40mg/ml concentration. It had highest and lowest zone of inhibition with Proteus vulgaris OX19 (30 mm) and Staphylococcus aureus (clinical iolate) (13 mm) respectively. Minimal inhibitory concentrations (MICs) were between concentrations of 20 - 160 mg/ml with aqueous or methanol extracts of Tagetes erecta and Tagetes patula flowers for most of the tested bacteria. Results of antimicrobial activity of extracts indicate that they possess potential broad spectrum antibacterial activity. Keywords: Tagetes flower extracts, antibacterial activit

A Rapid, Efficient and Green Method for Synthesis of 3,3'-Arylmethylene-bis-4-hydroxycoumarins without Use of any Solvent, Catalyst or Solid Surface

Abstract: A rapid, efficient and green methodology has been developed for the synthesis of 3,3'-arylmethylene-bis-4-hydroxycoumarins by microwave assisted condensation of aromatic aldehydes and 4-hydroxycoumarin without use of any solvent, catalyst or solid surface

Fabrication of magnetite nanocrystals in alcohol/water mixed solvents: catalytic and colloid property evaluation

In this work, Fe3O4 nanocrystals have been synthesized by homogeneous precipitation in different alcohol/water (1 : 1) solvent mixtures at two different temperatures to elucidate the role of the dielectric constant (ε) of the reaction medium. The effects of different solvents on the catalytic activity of precipitated NPs in carbon combustion were examined. HRTEM images, SAED and XRD confirmed that the nanocrystals are of pure fcc inverse spinel Fe3O4 phase with narrow size distribution, and the crystals are completely dispersible in water. The morphological features of the nanocrystals, such as their surface termination and shape of the Fe3O4 NPs, were analyzed by HR-TEM. As ε decreases, the crystal size decreases for mono-ol systems compared to ∼13 nm size in water, whereas ethylene glycol/water yields finer ∼8.2 nm crystals although it has the highest ε among the mono-/poly-ols. A soot combustion study demonstrates that the catalytic activity is mainly due to the available surface area along with the exposure of active crystallographic facets. A study of the colloids by light scattering shows that the alcohol mediated process produces 16 to 33 nm MNP clusters composed of 2 to 3 particles in highly stable aqueous magnetic fluids. The relatively high temperature process favors higher crystallinity and particle size with reduced colloidal stability in the aqueous phase. The nanocrystalline powders and the dispersed colloids have excellent potential applications in biotechnology and selective catalysis and also as ferrofluids

Highly Sensitive and Wearable ZnO-Graphene Nanocomposite-Based Strain Sensors for Human Motion Detection

Flexible electronic sensors have garnered considerable interest in wearable health-monitoring devices and electronic skin. In this work, a simple method for the fabrication of flexible zinc oxide-graphene nanoplatelet (ZnO-GNP) nanocomposite-based strain sensors has been proposed. The sensing element was deposited on the polydimethylsiloxane (PDMS) substrate by a facile spin and peel strategy to yield flexible sandwiched sensors. The effect of varying the blending ratio of the constituents on the electromechanical responses of the sensors was studied. The sensors exhibited high stretchability, good sensitivity, high reversibility, and superior stability under tensile and bending loads. The flexible nanocomposite sensors were able to detect extensive human movements such as bending of the elbow, wrist, and finger and also subtle motions such as eye blinking, wrist pulse, and phonation. Owing to the facile and economical fabrication method, high sensitivity, and good reversibility, the ZnO-GNP sensors have a high prospect of application in wearable health-monitoring devices, robotics, and various forms of human-machine interface

Effect of Neonicotinoids on Bacterial Symbionts and Insecticide-Resistant Gene in Whitefly, Bemisia tabaci

The silverleaf whitefly, Bemisia tabaci (Gennadius, Hemiptera: Aleyrodidae), is a major threat to field and horticultural crops worldwide. Persistent use of insecticides for the management of this pest is a lingering problem. In the present study, the status of sensitivity of B. tabaci to two neonicotinoids, imidacloprid and thiamethoxam, was evaluated. The expression pattern of two cytochrome P450 (cyp) genes and changes in the relative amount of symbionts in insecticide-treated B. tabaci were also assessed. Quantitative PCR (qPCR) studies indicate that the CYP6CM1 and CYP6CX1 genes were always expressed higher in imidacloprid-treated whitefly, suggesting a correlation between gene expression and the insect’s ability to detoxify toxic compounds such as insecticides. In addition, the thiamethoxam-treated population harbored higher Portiera and lower Rickettsia titers, whereas the imidacloprid-treated population harbored more Rickettsia at different time intervals. Interestingly, we also examined that an increase in exposure to both the insecticides resulted in a reduction in the mutualistic partners from their insect host. These differential responses of endosymbionts to insecticide exposure imply the complex interactions among the symbionts inside the host insect. The results also provide a deeper understanding of the molecular mechanism of resistance development that might be useful for formulating effective management strategies to control B. tabaci by manipulating symbionts and detoxifying genes

Effect of Banana Bunchy Top Virus on the Heat Shock Protein Genes of Pentalonia nigronervosa during Temperature Susceptibility and Its Effect on Virus Transmission

Acquisition of plant viruses is known to exert various effects on vectors’ developmental biology. Pentalonia nigronervosa is the only known vector of banana bunchy top virus (BBTV), which is an economically detrimental virus infecting banana cultivars all over the world. In the present study, the developmental biology of viruliferous (Vr) and non-viruliferous (NVr) aphids was compared, with a marked reduction noted in the lifespan of aphids upon acquisition of BBTV. Among all the environmental parameters temperature is an important determinant of an insect’s abundance and geographical distribution. Temperature susceptibility of P. nigronervosa was scrutinized by comparing the mortality percentage and differential expression pattern of three heat shock proteins (Hsps; Hsp40, Hsp70, and Hsp90) at the mRNA level between NVr and Vr aphids. After exposure to different temperature stress (5 °C, 15 °C, 38 °C and 25 °C as control) highest mortality of Vr aphids were recorded at 5 °C. Analysis of expression levels of Hsp genes using qPCR showed that both cold and heat shock treatment stimulated higher expression of the three Hsps at various rates in Vr than NVr aphids.. Finally, the effect of temperature stress on the BBTV titer level and their transmission by P.nigronervosa was determined by absolute quantification. The transmission efficiency along with the virus titer was found to be the lowest at 15 °C compared to 38 °C. Overall, our results provide a novel insight into the intricate interaction between aphid fitness and thermal stress concerning the acquisition and transmission of BBTV, which could be a roadmap for the future epidemiological control system

Synthesis of several types of 2,8-dioxabicyclo[3.3.1]nonanes using amberlyst-15 as an efficient recyclable heterogeneous catalyst

<p>A facile synthesis of 2,8-dioxabicyclo[3.3.1]nonane derivatives starting from simple molecules like 2-hydroxychalcones as one component and dimedone, 4-hydroxycoumarin, 2-hydroxynaphthoquinone, 2-naphthol or 1-naphthol, as the other has been achieved by use of amberlyst-15, a sulfonated polystyrene resin, as a recyclable heterogeneous catalyst. The methodology involves a domino sequence of Michael addition and two-stage cyclisation.</p