Microbiological Assay of Patulin, Using Bacillus megaterium

1975 ◽  
Vol 58 (3) ◽  
pp. 497-499 ◽  
Author(s):  
William T Stott ◽  
Lloyd B Bullerman
Keyword(s):  
Thin Layer ◽  
Bacillus Megaterium ◽  
Apple Juice ◽  
Test Organism ◽  
Spectrophotometric Assay ◽  
Optimum Conditions ◽  
Liquid Media ◽  
Suitable Test ◽  
Assay Methods ◽  
Quantitative Bioassay

Abstract Bacillus megaterium 1NRRL 1368 was found to be sensitive to patulin and a suitable test organism for an accurate, quantitative bioassay of the toxin. The optimum conditions for the test were determined. The response of the organism to patulin was found to be linear between 2 and 80 μg. When compared to thin layer chromatographic and spectrophotometric assay methods, the bioassay was found to be comparable in accuracy, but less sensitive. The test was found to be sensitive to 1.7 μg patulin. The assay is rapid (12–15 hr), simple, and inexpensive and can be used to verify the toxicity of samples, as well as to quantitatively measure patulin in samples of liquid media, apple juice, and corn.

A Microbiological Assay for Penicillic Acid1

1978 ◽  
Vol 41 (6) ◽  
pp. 432-434 ◽  
Author(s):  
F. J. OLIVIGNI ◽  
L. B. BULLERMAN
Keyword(s):  
Bacillus Subtilis ◽  
Biological Activity ◽  
Thin Layer ◽  
Linear Relationship ◽  
Acid Concentration ◽  
Spore Suspension ◽  
Liquid Media ◽  
Penicillic Acid ◽  
Bioassay Method ◽  
Quantitative Bioassay

Six bactertial cultures were studied in a search for an organism sensitive to penicillic acid suitable for use in a quantitative bioassay of this mycotoxin. A vegetative culture and a commercially prepared spore suspension of Bacillus subtilis were both sensitive to as little as 1 μg of penicillic acid and exhibited a linear relationship between 1 and 100 μg. The bioassay method was comparable in accuracy to thin layer chromatographic assay. The procedure was used to verify the biological activity of sample extracts, as well as to quantitate penicillic acid concentration in samples of liquid media and corn. The bioassay is sensitive, rapid (15–17 h), simple and inexpensive.

Comparison of radioimmunoassay and thin layer chromatographie assay methods for estimation of plasma prednisolone concentrations

1981 ◽  
Vol 6 (2) ◽  
pp. 137-142 ◽  
Author(s):  
S.M.H. Al-Habet ◽  
W.A.C. McAllister ◽  
J.V. Collins ◽  
H.J. Rogers
Keyword(s):  
Thin Layer ◽  
Assay Methods

Some Principles of Microbiological Turbidimetric Assays of Antibiotics

1979 ◽  
Vol 62 (4) ◽  
pp. 951-956
Author(s):  
Robert A Rippere
Keyword(s):  
Linear Response ◽  
Test Organism ◽  
Limited Range ◽  
Liquid Media ◽  
Agar Diffusion ◽  
Assay Procedure ◽  
Test Organisms ◽  
Effective Use

Abstract Turbidimetric methods for determining the potency of antibiotics are inherently more accurate and more precise than are comparable agar diffusion procedures, but assays conducted in liquid media are subject to degradation from less than ideal conditions to a much greater extent than are diffusion methods. The relationships between test organisms, antibiotics, and assay concentrations are discussed. A valid assay procedure must produce a linear response with an adequate slope (–0.4 to –1.2) by the test organism to increasing concentrations of drug; such linear response normally occurs over a limited range of concentrations. Criteria used to select photometers that offer the greatest advantages to analytical microbiologists are described, with guidelines for the most effective use of the chosen instrument.

Bioautographic Method for Evaluation of Glycopeptide Actaplanin in Milk

1986 ◽  
Vol 69 (6) ◽  
pp. 938-940
Author(s):  
Georges F Bories ◽  
Maryse M Baradat ◽  
Denis E Corpet
Keyword(s):  
Bacillus Subtilis ◽  
Thin Layer ◽  
Nutritional Value ◽  
Test Organism ◽  
Ammonium Hydroxide ◽  
Glycopeptide Antibiotic ◽  
Resin Column ◽  
Single Spot ◽  
Bioautographic Method ◽  
Layer Chromatography

Abstract A bioautographic method is described that allows the identification and semiquantitation of residues of the glycopeptide antibiotic actaplanin in cow’s milk at 0.01 ppm. The milk sample is precipitated with acetonitrile and the resultant pellet is extracted by a buffer. This extract is defatted, then chromatographed on an Amberlite resin column. Actaplanin is eluted with methanol-HCI. Purified extract is then chromatographed on a cellulose thin layer, developed in a methanol-chloroform- ammonium hydroxide mixture. This thin layer chromatography increased the sensitivity of the determination by concentrating the actaplanin components in a single spot. The antibiotic was then detected by bioautography, using Bacillus subtilis as a test organism. Parameters influencing the diffusion of the antibiotic (namely, the nature and concentration of the agar-agar), and the sensitivity of the test strain (namely, the nutritional value of the medium, and the addition of a synergistic inhibitor) have been optimized.

Enhanced Photoelectrical Performance of DSSC by Co-Doped SnO2 Nanoparticles

2013 ◽  
Vol 17 ◽  
pp. 82-93 ◽  
Author(s):  
C. Indira Priyadharsini ◽  
A. Prakasam ◽  
P.M. Anbarasan
Keyword(s):  
Thin Film ◽  
Thin Layer ◽  
Conversion Efficiency ◽  
Protective Layer ◽  
Natural Dyes ◽  
Optimum Conditions ◽  
Xrd Pattern ◽  
Nano Scale ◽  
Co Doped

Investigation of the I-V characteristics of the DSSC based on interconnected with cobalt-doped SnO2 nanoparticles covered with a nano-scale thin layer which was absorbed by natural dyes are described. The presence of co-doped SnO2 has been confirmed by its characteristic XRD pattern and the shape of the particle is confirmed by SEM. The thickness of the protective layer can be conveniently controlled by the mole value of co-doped SnO2 used in the preparation of the thin film and the optimum conditions for best performance of the DSSC are presented together with possible explanation for the variations observed. An optimum light-to-electricity conversion efficiency of 0.37 % in the presence of a layer of co-doped SnO2 has been obtained which enhancement over the cell prepared with other natural dyes. The characterization of the sample using different techniques was explained (change the sentence).

scholarly journals High throughput microwell spectrophotometric assay for olmesartan medoxomil in tablets based on its charge-transfer reaction with DDQ

2014 ◽  
Vol 64 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Ibrahim A. Darwish ◽  
Tanveer A. Wani ◽  
Nasr Y. Khalil ◽  
Hamdy M. Abdel-Rahman
Keyword(s):  
Charge Transfer ◽  
High Throughput ◽  
Olmesartan Medoxomil ◽  
Spectrophotometric Assay ◽  
Charge Transfer Reaction ◽  
Optimum Conditions ◽  
Accuracy And Precision ◽  
Ct Complex ◽  
The Cost ◽  
Development And Validation

Abstract The study describes the development and validation of a new microwell-based spectrophotometric assay for determination of olmesartan medoxomil (OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as an n-electron donor and 2,3-dichloro- -5,6-dicyano-1,4-benzoquinone (DDQ) as a p-electron acceptor was investigated, and employed as the basis for the development of the new assay. The proposed assay was conducted in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm with a microplate reader. Optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, a linear relationship with a good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 2-200 μg per well. The limits of detection and quantitation were 0.53 and 1.61 μg per well, respectively. No interference was observed from the excipients present in OLM tablets or from hydrochlorothiazide and amlodipine besylate that were co-formulated with OLM in some of its formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has a great practical value in the routine analysis of OLM in quality control laboratories, since it has a high throughput property and consumes low volumes of organic solvent. It thus offers a reduction in the exposure of analysts to the toxic effects of organic solvents, as well as a reduction in the cost of analysis.

Sporulation and Toxin Production by Clostridium botulinum Type G

1979 ◽  
Vol 42 (12) ◽  
pp. 965-967 ◽  
Author(s):  
H. M. SOLOMON ◽  
D. A. KAUTTER
Keyword(s):  
Comparative Study ◽  
Intraperitoneal Injection ◽  
Clostridium Botulinum ◽  
Solid Medium ◽  
Toxin Production ◽  
Optimum Conditions ◽  
Liquid Media ◽  
Botulinum Type ◽  
The Media

A comparative study was conducted to determine the optimum conditions for sporulation and toxin production by Clostridium botulinum type G, strain 89. One solid and four liquid media were compared for their ability to promote sporulation. After being inoculated, the media were incubated at 35 C for 12 days, at 30 C for 16 days, and at 26 C for 21 days. Spores were harvested by centrifugation, washed 3 times and resuspended to give a 35 × concentration, then counted by the MPN procedure. Spores grown on the solid medium at 35 C for 16 days gave higher counts than those grown at the same temperature in the liquid media. Toxin production was studied in eight media at 35, 30 and 26 C over a 24-day period with samplings every 2 to 3 days. Three of the media contained trypsin and five were trypsinized after growth. Toxin titers were determined by intraperitoneal injection of mice and expressed as MLD/ml of culture. Higher toxin titers were obtained at 26 and 30 C in media containing 0.4% glucose.

scholarly journals A new spectrophotometric assay for citrate synthase and its use to assess the inhibitory effects of palmitoyl thioesters

1988 ◽  
Vol 251 (3) ◽  
pp. 803-807 ◽  
Author(s):  
A J Else ◽  
S J Barnes ◽  
M J Danson ◽  
P D J Weitzman
Keyword(s):  
Escherichia Coli ◽  
Bacillus Megaterium ◽  
Citrate Synthase ◽  
Spectrophotometric Assay ◽  
Time Dependent ◽  
Inhibitory Effects ◽  
E Coli ◽  
Cell Extracts ◽  
Thioester Bond ◽  
High Concentrations

We have demonstrated that citrate synthase may be assayed by a simple, discontinuous, spectrophotometric procedure based on the measurement of oxaloacetate utilization with 2,4-dinitrophenylhydrazine. The assay is applicable both to the purified enzyme and to cell extracts, and has the advantage that it can be used in the presence of high concentrations of thiols and thioesters. We have used this new assay in part of our investigations into the inhibitory effects of palmitoyl thioesters on diverse citrate synthases. Both palmitoyl-CoA and palmitoyl thioglycollate inhibit citrate synthases from pig heart, Bacillus megaterium and Escherichia coli, the E. coli enzyme showing the greatest sensitivity to these effectors. With palmitoyl-CoA the extent of inhibition is time-dependent, but the enzymes can be protected from the effect by the substrates oxaloacetate and acetyl-CoA. Using the dinitrophenylhydrazine assay, we have shown that the thioester bond is essential for inhibition; that is, if the palmitoyl thioesters are cleaved to give a mixture of palmitate and a thiol compound, the inhibitions of pig heart and B. megaterium citrate synthases are eliminated and that of the E. coli enzyme is markedly decreased.

Improved Method for the Thin Layer Chromatographic Determination of Patulin in Apple Juice

1973 ◽  
Vol 56 (4) ◽  
pp. 813-816 ◽  
Author(s):  
Peter M Scott ◽  
Barry P C Kennedy
Keyword(s):  
Thin Layer ◽  
Ethyl Acetate ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Apple Juice ◽  
Chromatographic Determination ◽  
Improved Method ◽  
Layer Chromatography ◽  
Hydrochloride Solution

Abstract Apple juice from a freshly opened container is extracted 3 times with ethyl acetate. The extract is dried, concentrated, diluted with benzene, and added to a silica gel column. Patulin is eluted by benzene-ethyl acetate (75+25) and detected by thin layer chromatography, using a 3-methyl-2-benzothiazolinone hydrazone hydrochloride solution as the spray reagent. Satisfactory recoveries were obtained for patulin added to apple juice at levels of 25–400 μg/L.

A MICROBIOLOGICAL ASSAY FOR THE QUANTITATIVE DETERMINATION OF GLYCEROL

1960 ◽  
Vol 6 (3) ◽  
pp. 283-287 ◽  
Author(s):  
L. Eidus ◽  
B. B. Diena ◽  
A. C. Maniar ◽  
L. Greenberg
Keyword(s):  
Thin Layer ◽  
Quantitative Determination ◽  
Test Organism ◽  
Microbiological Assay ◽  
Nutrient Agar ◽  
Glycerol Solution ◽  
Zone Size ◽  
Chemical Methods ◽  
Chemical Assay

A microbiological assay has been developed using the techniques of assay for antibiotics. Metal cylinders were placed on plates prepared by overlaying a thin layer of seed agar, inoculated with a test organism, on a base of nutrient agar. Appropriate dilutions of a standard glycerol solution and of the glycerol preparations being tested were added to the proper cylinders. The plates were incubated and the zone sizes around the cylinders measured. The potency of the preparations was determined by comparing the average zone size of the unknown preparations with that of the standard. The method proved to be simple to perform, and in the absence of interfering substances, yielded essentially the same results as chemical methods. A number of carbohydrates—glucose, laevulose, maltose, mannitol, mannose, saccharose, and trehalose—interfered with assay results so that the method cannot be used for glycerol determinations in mixtures where they are present. No interference, however, was noted with d-arabitol and erythritol, which were found to interfere with the chemical assay.

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