Characterization of the biosorption of fast black azo dye K salt by the bacterium Rhodopseudomonas palustris 51ATA strain

BACKGROUND: Removal of dyes from wastewater by microorganisms through adsorption, degradation, or accumulation has been investigated. Biological methods used for dye treatment are generally always effective and environmentally friendly. In this study, biosorption of the Fast Black K salt azo dye by the bacterium Rhodopseudomonas palustris 51ATA was studied spectrophotometrically, at various pH (2­10), temperatures (25°C, 35°C, and 45°C) and dye concentrations (25­400 mg L-1). RESULTS: The bacterial strain showed extremely good dye-removing potential at various dye concentrations. IR studies at different temperatures showed that the dye was adsorbed on the bacterial surface at lower temperatures. Characteristics of the adsorption process were investigated by Scatchard analysis at 25°C and 35°C. Scatchard analysis of the equilibrium binding data for the dye on this bacterium gave rise to linear plots, indicating that the Langmuir model could be applied. The regression coefficients obtained for the dye from the Freundlich and Langmuir models were significant and divergence from the Scatchard plot was observed. CONCLUSION: The adsorption behavior of the dye on this bacterium was expressed by the Langmuir, Freundlich, and Temkin isotherms. The adsorption data with respect to various temperatures provided an excellent fit to the Freundlich isotherm. However, when the Langmuir and Temkin isotherm models were applied to these data, a good fit was only obtained for the dye at lower temperatures, thus indicating that the biosorption ability of R. palustris 51ATA is dependent on temperature, pH, and dye concentration.

Screening of endophytic fungi from Huperzia serrata for acetylcholinesterase inhibitory activity and its taxonomic identification / 中国中药杂志

<p><b>OBJECTIVE</b>To screen out fungus strains with acetylcholinesterase inhibitory activity from Huperzia serrata.</p><p><b>METHOD</b>Endophytic fungi fermentation products from 59 H. serrata strains were stained with acetylcholinesterase hydrolyzed alpha-naphthaleneacetic ethyl ester and fast blue B salt, and screened for acetylcholinesterase inhibitory activity with thin-layer chromatography-bioautography. Target strains were classified and identified through the sequence analysis on 18s rDNA and 5.8s rDNA combined with morphological characteristics.</p><p><b>RESULT</b>Fungus strain LQ2F01 from H. serrata showed positive color reaction in the screening for acetylcholinesterase inhibitory activity. The sequence analysis on 18s rDNA and 5.8s rDNA combined with morphological characteristics showed the strain LQ2F01 belonged to Acremonium.</p><p><b>CONCLUSION</b>Endophytic Fungi LQ2F01 from H. serrata shows identical acetylcholinesterase inhibitory activity with the host plant, which is of great significance to the development of natural medicines and the studies on the relationship between the endophytic gungi and the host plant.</p>

Biological Characterization of Marssonina coronaria Associated with Apple Blotch Disease

Marssonina coronaria associated with apple blotch disease causes severe premature defoliation, and is widely distributed in Korea. Thirteen isolates were collected from orchards located in Gyeongbuk Province from 2005~2007. All isolates displayed over 99.6% and 99.2% sequence similarity to each other in internal transcribed spacer regions and partial sequences of 28S rDNA, respectively. The isolates were phylogenetically closely related to Chinese isolates. Selected isolates did not differ in their pathogenicity. The optimum conditions for fungal growth were 20degrees C and pH 6 on peptone potato dextrose agar (PPDA). Peptone and mannose were the best nitrogen and carbon source, respectively. Fungal growth was better on PPDA than on common potato dextrose agar. This study provides valuable information for integrated disease management program and facilitates the routine culturing of M. coronaria.

Rapid colorimetric assay of diclofenac sodium tablets using 4-carboxyl-2, 6-dinitro-benzene diazonium ion [CDNBD]

This study describes a novel simple, rapid and sensitive colorimetric assay method for diclofenac sodium tablets. The method is based on a simple aromatic ring derivatization technique using newly developed 4-carboxyl-2, 6-dinitrobenzenediazonium ion [CDNBD] as chromogenic derivatizing reagent with subsequent formation of an azo dye. The diazo coupling reaction was carried out between CDNBD and diclofenac. Optimization studies for time and temperature was conducted using the method of steepest ascent. The UV absorption spectrum was recorded and the stoichiometric ratio for the drug and reagent was done by continuous variation method. Optimal calibration range was fixed [1-way ANOVA] and then the method was applied to dosage form analysis. Comparison of dosage form analysis was done with the BP HPLC method. The diazo coupling reaction is very fast and optimization studies established an optimal reaction immediately after mixing the reaction mixture in a vortex mixer for 10 sec. A new absorption maximum [lamda max] at 470nm was selected as analytical wavelength. The assays were linear over 1.35 -10.8 micro g/ml of diclofenac and the reaction required a 2:1 reagent/drug stoichiometric ratio. The new method has a low limit of detection of 0.27 microg/ml, and was reproducible over a three-day assessment of precision [RSD 2.31%]. The method has been successfully applied to the assay of diclofenac sodium slow-release tablets and found to be of equivalent accuracy [p>0.05] with the official [B.P 1998] HPLC method. The new method has distinct advantages of speed, simplicity, sensitivity, and more affordable instrumentation and could find application as a rapid analytical method for diclofenac sodium tablets

Electrochemical behavior of the product of coupling of crotononitrile with aryldiazonium salts

It has been reported that compounds la-c couple with aromatic diazonium salts to yield the corresponding hydrazones 2a-c, which readily cyclize into the pyridazines 3a-c, c.f. Plate 1. However, Mittelbach [1] reported that at least the product of coupling component 1 c with aromatic diazonium salts would be 3 c, so that compound 2 c could have never been isolated. This led Mettelbach [1] to suggest that the coupling products assigned by Elnagdi et al. [2] as being of the types of compound 2 would be in fact related to compounds 3

Spectrophotometric determination of tetracycline by coupling with diazonium salts

A simple, rapid and accurate spectrophotometric method for the determination of tetracycline [TC] in aqueous solution was developed. The method was based on the coupling reaction between TC and diazontized p-nitroaniline [I], sulfanilic acid [II], and sulfanilamide [III] to form stable dyes. The variables affecting development of the color were investigated and the conditions optimized. The Beer's law was obeyed for up to 19, 70 and 40 ppm on using I, II and III, respectively. Their absorptivities [L mol-1 cm-1] and Sandell's sensitivities [mug cm-2] are 125 x 104, 4.0 x 104 and 0.13 x 104 and 38.4 x 10-3, 175 x 10-3 and 148.0 x 10-3, respectively, for I, II and III. The recoveries of the method for I, II and III were 100.07 +/- 0.24, 98.97 +/- 0.64 and 99.95 +/- 0.45 for TC, while the recoveries for the dosage forms were 100.2 +/- 0.277, 100.0075 +/- 0.227 and 99.075 +/- 0.297, respectively. The proposed methods were applied for the quantitation of TC in pharmaceutical preparations with high precision and accuracy. The nature of the dye formation and the structure of mono azo dye was suggested

Spectrophotometric determination of oxytetracycline by coupling with diazonium salts

Diazotized p-nitroaniline [I], sulfanilic acid [II] and sulfanilamide [III] were used for the spectrophotometric determination of oxytetracycline [OTC]. The procedure is based on the observation of that in slightly alkaline medium OTC reacts with I, II and III. A stable azo dye is formed and show maximum absorption at 550, 560, and 575 nm, respectively. The variable affecting development of the color have been investigated and the conditions optimized. Beer's law is obeyed for up to 25, 90 and 90 mug/ml on using I, II and III, respectively. Molar absorptivities [L mol-1 cm-1] and Sandell's sensitivities [mug cm-2 per 0.001 absorbance unit] are respectively; 0.83 x 104 and 57.8 x 10-3, 0.14 x 104 and 200 x 10-3 and 0.12 x 104 and 176.5 x 10-3. The mean percentage accuracies were 99.9 +/- 1.75, 99.95 +/- 0.71. The results obtained either in pure form or in pharmaceutical formulations are accurate and precise. The nature of the dye was discussed and the structure of a mono azo dye was suggested

Reaction of biindone with amines and diazonium salts

The biindone I reacted with morpholine or piperidine and formaldehyde to give the corresponding Mannich bases IIa-b. Treatment of I with formaldehyde, and formaldehyde in AcOH, afforded II and IV, respectively. Compounds V and VI were prepared by treating I with benzaniline and isatinanil, respectively. Coupling of I with benzenediazonium chloride led to the formation of VII

reaction of azides with active methylene reagents

The reaction of active methylene reagents with sulphonylazides is one of the best known methods for preparing polyfunctional diazo compounds. However, active methylene nitriles and active methylene ketones have been shown to afford in some cases cyclic 1,2,3-triazoles. Reactions of this type have been reviewed several times in literature .In connection with our interest in the synthesis of heterocyclic derivatives from activated nitriles we have investigated the reaction of p-tosylazide with several activated nitrile derivatives. It has been found that tosylazide reacts with benzoylacetonitrile in ether in the presence of sodium hydroxide to yield a product of molecular formula C[16]H[12]N[4]O[2]S. Structure 3 was readily established for the reaction product based on its IR spectrum which revealed the absence of diazo group absorption. Treatment of compound 3 with equimolecular amount of hydrazine hydrate at 100 degree in absence of a solvent afforded a mixture of two products of mp. 125 degree and 193 degree which were separated by fractional crystallization from ethanol. The product of the mp. 125 degree was shown to be the amidrazone 4 based on its analytical data and the absence of absorption for cyano- and diazo- functions in its IR spectrum. On the other hand, the other product revealed analytical data indicating that it is only an isomer for 3; its IR spectrum revealed the presence of cyano- and diazo- functions, consequently structure 5 was suggested for this product. Similar isomerisatian of 1, 2, 3-triazoles into diazo- compounds has been observed in literature and reactions of this type have been summarized by Regitz. The isomerisatian of 3 into the diazo- derivative 5 prompted us to try isomerisatian of the 1,2,3-triazole 6, prepared by Regitz et al by the reaction of malononitrile with 1, into the diazo- derivative 7. However, the reaction afforded the amidrazone on treatment with phenylhydrazine. Compound 1 also reacted with 1,1, 3-tricyano-2- aminopropene under similar conditions to yield the 1,2,3-triazole derivative 10. Attempts to convert this compound into the diazo- derivative 11 by our procedure or other reported procedures for isomerising 1, 2, 3-triazoles into diazo-derivatives, were unsuccessful. In contrast to the observed behaviour of active methylene nitriles, the aryl-hydrazononitriles 12a-c were treated with sodium azide in DMF to yield 1,2,3,4-tetrazole derivatives 13a-c. To our knowledge only few examples of the reaction of nitriles with azides to yield tetrazoles have been reported in literature Compound 1 reacted with 1, 3-diphenyl-5- aminopyrazole [14a] to yield the pyrazolo [4, 5-d] 1, 2, 3-triazole derivative 15. On the other hand, the aminopyrazole 14b reacted under the same conditions to yield the tetrazene derivative 16. Under a variety of conditions l-phenyl-3-methyl-2-pyrazolin-5-one reacted with tosylazide to yield the hydrazo derivative 18. The formation of 18 is assumed to proceed via intermediacy of the diazo derivative 19 formed through the triazine 20 [c.f. chart 2]. In order to get evidence for this assumption the reaction of 17 with 1 was conducted in the presence of [3-naphthol. The coupling product 21 was isolated in addition to 18 and the azo derivative 22