Novel antibacterial activity of Terfizia claveryi aqueous extract against clinical isolates of corneal ulcer

Terfizia claveryi was examined for in vitro antibacterial activity using the disc diffusion, well diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). T.claveryi exhibited excellent antibacterial activity against all clinical isolates of corneal ulcer tested, especially against Pseudomonas aeruginosa which showed the maximum antibacterial activity with mean zone of inhibition 20.33 mm at concentration of 100 mg/ml. The MIC for Staphylococcus aureus ranged from 0.040-1.250 mg/ml and MBC for Escherichia coli was 75 μl/ml. In the present study, the MIC value of the active aqueous extract were lower than the MBC values suggesting that, T. claveryi aqueous extracts were bacteriostatic at lower concentration but bactericidal at higher concentration. Also, the bacterial zone of inhibition increased with the increasing concentration of T. claveryi aqueous extract. To the best of our knowledge, this is the first report for the novel antibacterial activity of T.claveryi aqueous extract. This active compound may be used as alternative therapeutic drug for the control of corneal infections. However, further research is needed to examine its in vivo mechanism of action, toxicity, and therapeutic effect.Key words: Bacteria, corneal infection, antimicrobials, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), Terfizia claveryi

EFFICACY OF COMMERCIAL HOUSEHOLD INSECTICIDE AEROSOL SPRAYS AGAINST AEDES AEGYPTI (LINN.) UNDER SIMULATED FIELD CONDITIONS

Abstract. A simulated field study on the efficacy of commercial household aerosol insecticides was conducted. The bioefficacy of three pyrethroid aerosols, designated as PA1, PA2 and PA3, was tested in cabins furnished to simulate bedroom conditions. Each aerosol product was tested against lab-bred Aedes aegypti mosquitoes based on the insecticide manufacturers' recommended dosages. Ten cages with mosquitoes were placed in the following locations: one cage in the middle of the room; two each on and underneath the bed; three each placed inside, behind and on top of the wardrobe; and four placed on and in the desk. With the desk, each cage was placed inside each of three drawers (totally closed, partially closed and opened). Prior to the experiments, the discharge rate of each aerosol can was determined. Ten to 20 lab-bred 2-5 day-old sugar-fed Ae. aegypti adult mosquitoes were placed inside the test cages. The aerosol was then discharged into the cabin at the recommended dosage. After 30 minutes, the mosquitoes were transferred into clean paper cups and their mortality recorded after 24 hours. All the aerosols induced complete or very high mortality in the caged Ae. aegypti females, except in the cages hidden completely inside the drawers and wardrobes. Insecticide droplet analysis indicated variable uniformity of the droplets was produced. The aerosol insecticides were effective against mosquitoes provided they were used in accordance with the manufacturers' recommendations

Noble silver nanoparticles (AgNPs) synthesis and characterization of fig Ficus carica (fig) leaf extract and its antimicrobial effect against clinical isolates from corneal ulcer

Nanotechnology is rapidly growing with nanoparticles produced and utilized in a wide range of pharmaceutical and commercial products throughout the world. In this study, fig (Ficus carica) leaf extracts were used for ecofriendly extracellular synthesis of stable silver nanoparticles (AgNPs) by treating an aqueous silver nitrate (1 mM) solution and using the plant F. carica leaf extracts as reducing agents. The bioreduced silver nanoparticles were characterized by ultra violet visible (UV-Vis) spectrophotometer, Fourier transform infra-red (FTIR) spectroscopy and transmission electron microscopy (TEM). The average particle size ranged from 5 to 40 nm. The particle size could be controlled by changing the reaction temperature, leaf broth concentration and AgNO3 concentration. Further, these biologically synthesized nanoparticles concentration of 50 µl were found to be highly effective and exhibited maximum microbial activity with mean zone of inhibition 20.33±1.00 mm and 18.00±1.00 against pseudomonas aeruginosa and Aspergillus fumigatus isolated from human corneal ulcer patients. This environmentally friendly green synthesis is an eco-friendly approach to conventional chemical synthesis and can potentially be used in various areas such as food, cosmetics, and medical applications and hope the recent technology can provide next generation of anti-microbials.Keywords: Ficus carica, silver nanoparticles, characterization, antimicrobial activity.African Journal of Biotechnology, Vol 13(45) 4275-428

Theoretical spectroscopy and metastability of BeS and its cation

International audienceMulticonfiguration self-consistent field and multiconfiguration reference interaction including the Davidson's correction techniques were employed to calculate the potential energy curves (PECs) of the BeS/BeS+ electronic states correlating to the 4/5 lowest dissociation limits. After nuclear motion treatment, we deduced reliable spectroscopic data for the neutral and cationic bound states. For BeS, the transition moments and spin-orbit couplings were also evaluated and used later with the PECs to deduce the rovibronic transition probabilities and the radiative lifetimes in the low-lying states, and to investigate the unimolecular decomposition processes of BeS (X(1)Sigma(+), A(1)Pi, (3)Sigma(+) and B(1)Sigma(+)) leading to Be((1)S(g)) + S((3)P(g)). The prominent mechanism is a spin-orbit induced predissociation via the repulsive BeS(1(3)Sigma) state. Finally, we give the single ionization spectrum of BeS (X(1)Sigma(+)) populating the BeS(+) (X(2)Pi, 1(2)Sigma, 1(2)Sigma(+), 1(2)Sigma(+), 2(2)Sigma(+), 2(2)Pi and 3(2)Pi) electronic states. The adiabatic ionisation energy of BeS is estimated to be similar to 9.15 eV. (C) 2010 Published by Elsevier B. V

Theoretical investigations of the SH+ and LiS+ cations

International audienceReliable theoretical data on spectroscopy and spin-orbit matrix elements are computed for the lowest electronic states of SH+ and LiS+ ions. Accurate spectroscopic predictions for their excited electronic states are given. For SH+, polarization minima at large internuclear distances are located in addition to the strongly bound electronic states already known. For LiS+, our calculations confirm that the electronic ground state of this ion is of (3)Sigma(-) species and reveal the existence of a (1)Delta state presenting a potential well as deep as the potential of the ground state. Moreover, the LiS+ electronic excited states potential energy curves possess shallow potential minima in the molecular region and at long-internuclear distances. Generally, these shallow minima may be populated during low energy collisions between the corresponding atomic fragments. Finally, spin-orbit calculations have allowed giving accurate determinations of the spin-orbit splittings for these cations and elucidation of the predissociation mechanisms of SH+ leading to the formation of the S+ and H species in their electronic ground states. Accordingly, long-lived SH+ ions can be found in the (XE-)-E-3, a(1)Delta and b(1)Sigma(+) electronic states and the rovibrational levels of LiS+ in its electronically excited and ground states should be weakly perturbed. (C) 2006 Elsevier Inc. All rights reserved

Ajwa-Dates (<i>Phoenix dactylifera</i>)-Mediated Synthesis of Silver Nanoparticles and Their Anti-Bacterial, Anti-Biofilm, and Cytotoxic Potential

Green nanotechnology is the evolution of cost-effective and environmentally friendly processes for the production of metal-based nanoparticles due to medicinal importance and economic value. The aim of the present study was to biosynthesize and characterize silver nanoparticles (AgNPs) using the seed extract of Ajwa dates (Aw). The anti-bacteriostatic activity of biosynthesized Aw–AgNPs against Gram-positive and Gram-negative bacterial strains was evaluated. The anti-biofilm activity was examined by the tissue culture plate method. Lastly, the anti-cancer potential of Aw–AgNPs was investigated against the human breast cancer cell line HCC712. UV–visible absorption spectra exhibited the plasmon resonance peak at 430 nm, with the solution undergoing rapid color changes that verified the existence of biosynthesized silver nanoparticles in the solution. TEM and SEM images illustrated that the Aw–AgNPs were spherical and between 15 and 80 nm in diameter. The reduction and stabilization of Aw–AgNPs was due to the functional groups present in the biomolecules of the Ajwa seeds, as identified by FTIR. The Aw–AgNPs exhibited significant anti-bacterial activity against all the tested bacterial strains. Moreover, the Aw–AgNPs efficiently hampered the biofilm formation of the bacterial strains and exhibited cytotoxicity at various concentrations. Overall, these findings suggest that biosynthesized Aw–AgNPs may be used as a potential therapeutic formulation against bacterial infections and breast cancer