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Disc Method (disc + method)
Selected AbstractsGrowth-inhibiting effects of seco-tanapartholides identified in Artemisia princeps var. orientalis whole plant on human intestinal bacteriaJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2003S.-H. Cho Abstract Aims: The present work aimed at isolating antibacterial constituents from the whole plant of Artemisia princeps var. orientalis active towards nine human intestinal bacteria. Methods and Results: The growth-inhibiting activities of materials derived from the Artemisia whole plant towards test bacteria were examined using an impregnated paper disc method. The biologically active constituents of the Artemisia whole plant were characterized as the sesquiterpene lactones seco-tanapartholides A and B by spectroscopic analysis. In a test using 1 mg per disc, seco-tanapartholides A and B produced a clear inhibitory effect against Clostridium perfringens, Bacteroides fragilis and Staphylococcus aureus. These compounds did not affect the growth of test lactic acid-producing bacteria (Bifidobacterium adolescentis, Bif. breve, Lactobacillus acidophilus and Lact. casei) and Escherichia coli, whereas weak growth inhibition towards Bif. bifidum was observed. At 0·5 mg per disc, seco-tanapartholides A and B exhibited moderate growth inhibition towards Cl. perfringens but weak growth inhibition towards Bact. fragilis and Staph. aureus. Conclusions: Inhibitory action of seco-tanapartholides A and B towards specific bacteria without any adverse effects on lactic acid-producing bacteria may be an indication of at least one of the pharmacological actions of A. princeps var. orientalis whole plant. Significance and Impact of the Study: These naturally occurring Artemisia whole plant-derived materials could be useful as a new preventive agent against various diseases caused by harmful intestinal bacteria such as clostridia. [source] Leaf Disc Inoculation, a Fast and Precise Test for the Screening of Metalaxyl Tolerance in Sunflower Downy MildewJOURNAL OF PHYTOPATHOLOGY, Issue 6 2001B. Rozynek A new method, based on leaf disc inoculation, was developed for the screening of metalaxyl tolerance in field isolates of Plasmopara halstedii. High-pressure liquid chromatography (HPLC) was used to determine the fungicide concentration in the inoculation medium and in the incubated leaf tissue over the test period. These measurements revealed that the fungicide concentration inside the leaf tissue within 24 h had adjusted to the concentration in the outer medium and remained constant for the time of cultivation over a period of more than 11 days. In contrast to whole seedling tests with application of the fungicide via seed dressing, the leaf disc method allows precise quantification of the effective fungicide concentration at the site of infection and is less space and time consuming. Metalaxyl tolerance of P. halstedii isolates was gradually determined according to the sporulation of the pathogen on sunflower leaf discs in the presence of increasing fungicide concentrations. Isolates collected in South Germany showed no tolerance and sporulation was prohibited when tests were carried out at 0.02 ,g (a.i.)/ml of metalaxyl or more. In contrast, a tolerant French isolate developed sporangia on leaf discs incubated in a metalaxyl solution of 100 ,g (a.i.)/ml. [source] Effectiveness of dentine bonding agents against cariogenic bacteria in vitro: a comparison of two methodsMOLECULAR ORAL MICROBIOLOGY, Issue 3 2003O. A. Schmidlin Data obtained from studies on the antimicrobial properties of bonding agents are the subject of controversy, probably because of methodological differences. This study compared two commonly used in vitro methods, the disc agar diffusion test and the well agar diffusion test. Agar plates were seeded with Streptococcus sobrinus, Lactobacillus gasseri, or Actinomyces naeslundii. For the well diffusion test, wells cut out of the agar were filled with the test material, and for the disc method, discs impregnated with the test material were applied to the agar; the discs and wells were both 9 mm in diameter. After incubation, measurements of the zones of inhibition showed little agreement between the two methods when bonding agents were tested; the mean differences (± sdiff) in the zones of inhibition between the methods were 0.7 ± 3.4 mm (P = 0.40, one sample t -test against zero), 4.9 ± 4.4 mm (P = 0.97), and 0.8 ± 4.3 mm (P = 0.47) for S. sobrinus, L. gasseri, and A. naeslundii, respectively. Mean differences were less contrasting when chlorhexidine and pure components were tested (P < 0.05 for S. sobrinus and L. gasseri). These results indicate the need for a gold standard method to evaluate the antimicrobial properties of bonding agents. [source] Studies on Synthesis and Pharmacological Activities of 1,2,4-Triazolo[3,4- b]1,3,4-thiadiazoles and their Dihydro AnaloguesARCHIV DER PHARMAZIE, Issue 4 2009Vinod Mathew Abstract 4-Amino-5-substituted aryl-3-mercapto-1,2,4-triazoles are versatile synthons for constructing various biologically active heterocycles. Starting from 4-amino-5-substituted aryl-3-mercapto-1,2,4-triazole 3a,c, a series of new 3,5-disubstituted-1,2,4-triazolo-[3,4- b]1,3,4-thiadiazoles and their 5,6-dihydrotriazolothiadiazoles were prepared. The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR, and mass spectra. The antimicrobial effects of the synthesized compounds were investigated using the paper disc method. Anti-inflammatory and analgesic activities of the synthesized compounds were assessed by carrageenan-induced rat paw oedema method and by Eddy's hot plate method, respectively. Some of the compounds exhibited promising antimicrobial activities as well as moderate to good anti-inflammatory activity and analgesic activity. [source] | ||||||||||