Atilla Öktemer

Larvicidal and sporal behaviour of Bacillus sphaericus 2362 in carrageenan microcapsules

Abstract Carrageenan microcapsules of the mosquito pathogen Bacillus sphaericus 2362 were prepared and tested for larvicidal activity against Culex sp. larvae in the laboratory. The durability of the bacterium in response to pH change, temperature, UV irradiation and several chemicals that can simulate polluted water habitats, in carrageenan beads with different polymer concentrations (0.5–2.0% w/v) was investigated. The results show that, with the protection of larvicidal activity, increased sporal resistance against these effects was achieved as compared to the free bacterium.

Antimicrobial activity studies on some piperidine and pyrrolidine substituted halogenobenzene derivatives

The in vitro antibacterial and antifungal activities of the compounds synthesised from some 1,2,3,5-tetrahalogeno benzenes in presence of sodium piperidide and sodium pyrrolidide (2,6-dipiperidino-1,4-dihalogenobenzenes; 2,6-dipyrrolidino-1,4-dibromobenzene; 2,4,6-tripyrrolidino chlorobenzene; and 1,3-dipyrrolidino benzene) were investigated. The in vitro antimicrobial activities were screened against the standard strains: Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633 as Gram positive, Yersinia enterocolitica ATCC 1501, Escherichia coli ATCC 11230 and Klebsiella pneumoniae as Gram negative, and Candida albicans as yeast-like fungus. Compounds (3, 5, 6, 7) inhibited the growth of all the test strains at MIC values of 32–512 μg/ml. None of the four compounds (1, 2, 4, 8) studied showed antimicrobial activity against any of the test strains within the MIC range 0.25–512 μg/ml.

IN VITRO ANTIMICROBIAL ACTIVITY STUDIES OF THIOETHOXY-AND THIOPHYENOXYHALOBENZENE DERIVATIVES

The in vitro antibacterial and antifungal activities of thioethoxyand thiophyenoxyhalobenzene derivatives were investigated. Thioethoxyand thiophyenoxyhalobenzenedervatives synthesized and identified by spectroscopic means IR and NMR and elemental analysis. The antibacterial and antifungal activities were measured by Minumum inhibition concentration (MIC) method against gram-positive bacteria i.e. Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633; Gram-negative bacteria as Yersinia enterocolitica ATCC 1501, Escherichia coli ATCC 11230, Klebsiella pneumoniae and fungus as Candida albicans from our strain collection. Antimicrobial activies of these compounds tended to increase with size and numerous and kinds of halogene and thiogroups substitutents.

Purification and characterization of organic solvent stable serine alkaline protease from newly isolated Bacillus circulans M34

A protease from newly isolated Bacillus circulans M34 was purified by Q-Sepharose anion exchange chromatography and Sepharose-bacitracin affinity chromatography followed by (NH4)2SO4 precipitation. The molecular mass of the purified enzyme was determined using SDS-PAGE. The optimum pH and temperature for protease activity were 11 and 50°C, respectively. The effect of various metal ions on protease activity was investigated. Alkaline protease from Bacillus circulans M34 wase activated by Zn(2+), Cu(2+) and Co(2+) up to 31%. The purified protease was found to be stable in the organic solvents, surfactants and oxidizing agent. The substrate specificity of purified protease was investigated towards different substrates. The protease was almost completely inhibited by the serine protease inhibitor phenylmethanesulfonyl fluoride. The kinetic parameters of the purified protease, maximum rate (Vmax) and Michaelis constant (Km), were determined using a Lineweaver-Burk plot.

Synthesis of 2,4-dihalogenofluorobenzenes and their antimicrobial and antifungal activity studies

The aim of this study was to synthesize and identify 2,4-dihalogenofluorobenzene (or trihalogenobenzene) derivatives by spectroscopic means, 1H-NMR and 19F-NMR. The 2,4-dihalofluorobenzene derivatives considered were 2,4-dichlorofluorobenzene (1), 2-bromo-4-chlorofluorobenzene (2), 2-iodo-4-chlorofluorobenzene(3), 2,5-dichlorofluorobenzene (4), 2-bromo-5-chlorofluorobenzene (5), 2-iodo-5-chlorofluorobenzene (6).The in vitro antibacterial and antifungal activities of trihalogenobenzene derivatives were studied against the bacteria Staphylococcus aureus ATCC 25923 Gram(+), Bacillus cereus ATCC 6633 Gram(+), Micrococcus flavus (clinical isolate) Gram(+), Morgenella morganii (clinical isolate) Gram(-), Escherichia coli ATCC 27853 Gram(-) and fungus Candida albicans (clinical isolate), obtained from the biology departments of the Pamukkale and Gazi Universities. The antibacterial and antifungal activities were measured by minimum inhibition concentration (MIC) method and the disc-diffusion method used to measure zone diameter against Gram-positive and Gram-negative bacteria and fungi. All these bacteria and fungi were studied against antibiotics to compare the zone diameters with the results from our treatments.

Crystal Structure of ent‐7α, 18‐Diacetoxykaur‐16‐ene (Epicandicandioldiacetate)

The title compound (C 24 H 36 O 4 ) crystallizes in the orthorhombic space group P2 1 2 1 2 with a=6.250(1) A, b=13.676(1) A, c=25.419(2) A, V=2172.7(1) A 3 , Z=4, D x =1.19 g.cm -3 . The structure was solved by direct methods and refined by full-matrix least-squares method (R=0.076). The title molecule is an entkaurene diterpene containing two acetoxy groups at positions C7 and C18, The ring junction A-B is in trans, while B-C is in cis, The rings A and B have chair conformations, while ring C has a twist conformation but the conformation of ring D is nearer to an envelope.

Synthesis, characterization, and investigations of antimicrobial activity of benzopyrans, benzofurans and spiro[4.5]decanes

Abstract In this study, the radical cyclization reactions of cyclic 1,3-dicarbonyl compounds (1a–c) and α,β-unsaturated alcohols (2a–d) through Mn(OAc)3 were performed. A series of biologically interesting dihydropyrans (3–5) and dihydrofurans (6–18) were synthesized as a result of these reactions. Spiro compounds (19–20) were obtained from the reactions of 1,3-dicarbonyl compounds and (E)-2,4-diphenyl-but-3-en-2-ol (2e). The unique structure of compound 19 was also confirmed by X-ray crystallography. In addition, the antibacterial activities of synthesized compounds were screened against some bacteria. Their zone diameters showed better results than some known antibiotics. GRAPHICAL ABSTRACT