A bacterial inhibition assay for corynetoxins from parasitized annual ryegrass

1983 ◽  
Vol 34 (5) ◽  
pp. 483 ◽  
Author(s):  
BA Stynes ◽  
P Vogel
Keyword(s):  
Growth Inhibition ◽  
Optical Density ◽  
Plant Extracts ◽  
Test Organism ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Density Measurements ◽  
Bacterial Inhibition ◽  
Crude Extracts ◽  
Sensitive Method

A rapid and sensitive method is described to detect and measure corynetoxins in extracts of ryegrass seed galls colonized by Corynebacterium rathayi, as well as in crude extracts of pasture samples containing such galls. The assay is done in microtitre plates by incorporating a test organism, C. tntrci, with a series of dilutions of plant extracts. The presence of at least 125 ng ml-1 of toxin inhibits the growth of C. tritici, which can be detected by optical density measurements. There is evidence that growth inhibition is due to the presence of corynetoxins. It is likely the test could also be used to detect the closely related tunicamycin compounds.

Purification of corynetoxins from galls of annual ryegrass infected with Corynebacterium rathayi

1984 ◽  
Vol 24 (127) ◽  
pp. 617 ◽  
Author(s):  
P Vogel ◽  
H Golding ◽  
A McWilliam ◽  
J Carlin
Keyword(s):  
Column Chromatography ◽  
Purification Procedure ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Bacterial Inhibition ◽  
Short Column ◽  
Crude Extracts ◽  
Annual Ryegrass Toxicity

An improved, rapid and efficient purification procedure of corynetoxins, the causal agents of annual ryegrass toxicity, is described. The method relies upon bacterial gall concentration from crude seedhead material and the use of Sep Pak 'Florisil' cartridges and 'short column' chromatography to purify corynetoxinsfrom crude extracts. Extracts were monitored for toxicity using a recently developed bacterial inhibition assay.

Corynetoxins are not detoxicated by in vitro fermentation in ovine rumen fluid

1986 ◽  
Vol 37 (5) ◽  
pp. 523 ◽  
Author(s):  
P Vogel ◽  
MG McGrath
Keyword(s):  
Rumen Fluid ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Lolium Rigidum ◽  
In Vitro Fermentation ◽  
Bacterial Inhibition ◽  
Annual Ryegrass Toxicity

Tunicamycin and seed galls of annual ryegrass (Lolium rigidum) containing corynetoxins, the causal agents of annual ryegrass toxicity, were incubated in ovine rumen fluid-buffer mixtures. A bacterial inhibition assay of extracted incubation mixtures revealed that no detoxication occurred under these in vitro conditions.

Measurements of the Fe3+ diffusion coefficient in Fricke Xylenol gel using optical density measurements

2014 ◽  
Vol 90 ◽  
pp. 241-244 ◽  
Author(s):  
Lucas Nonato de Oliveira ◽  
Francisco Glaildo Almeida Sampaio ◽  
Marcos Vasques Moreira ◽  
Adelaide de Almeida
Keyword(s):  
Diffusion Coefficient ◽  
Optical Density ◽  
Density Measurements

scholarly journals Anticariogenic Potential of Korean Native Plant Extracts against Streptococcus mutans

Planta Medica ◽  
2019 ◽  
Vol 85 (16) ◽  
pp. 1242-1252
Author(s):  
Yun-Chae Lee ◽  
Sung-Gook Cho ◽  
Sang-Woo Kim ◽  
Jeong Nam Kim
Keyword(s):  
Growth Inhibition ◽  
Streptococcus Mutans ◽  
Plant Extracts ◽  
Negative Control ◽  
Minimal Bactericidal Concentration ◽  
Native Plant ◽  
Plant Materials ◽  
The Individual ◽  
Adhesive Proteins

AbstractNumerous chemically synthesized compounds are widely used in oral hygiene products. However, due to their potential risk, there is a need to improve the safety and quality of dental care by seeking alternative control agents such as those naturally found in plant materials. Here we assessed antibacterial potentials of extracts from 100 species of Korean native plants against Streptococcus mutans on cariogenesis. Among those, extracts from five plants (Arctii Fructus, Caryopteris incana, Aralia continentalis, Symplocarpus renifolius, and Lamium amplexicaule) showed a growth inhibition of S. mutans. The five extracts were further individually evaluated for their minimal inhibitory concentration and minimal bactericidal concentration. Interestingly, a synergistic antibacterial activity was observed with the combination of sodium fluoride and the plant extracts. To determine the anti-biofilm activity of plant extracts, S. mutans was treated with increasing concentrations of the extracts in the range from 1250 to 3750 µg/mL. When S. mutans was grown in the defined biofilm medium containing the individual extracts of 47 species, the biofilm amount markedly decreased compared to that of a negative control. Notably, the extract of S. renifolius significantly downregulated the gtf and spaP genes for synthesis of glucan and adhesive proteins in S. mutans, and L. amplexicaule decreased the expression of gtfD gene. Therefore, these results demonstrate that the five plant extracts modulate survival and pathogenesis of S. mutans by growth inhibition and downregulation of the gene(s) implicated in biofilm formation.

Secondary Bone Grafting of Alveolar Clefts: A Densitometric Comparison of Iliac Crest and Tibial Bone Grafts

2001 ◽  
Vol 38 (1) ◽  
pp. 11-14 ◽  
Author(s):  
V. Sivarajasingam ◽  
G. Pell ◽  
M. Morse ◽  
J. P. Shepherd
Keyword(s):  
Bone Density ◽  
Optical Density ◽  
Bone Grafting ◽  
Iliac Crest ◽  
Objective Assessment ◽  
Bone Grafts ◽  
Orthodontic Appliances ◽  
Density Measurements ◽  
Tibial Bone ◽  
Alveolar Bone Grafting

Objective To evaluate changes in the optical density of secondary alveolar cleft bone grafts obtained from two different donor sites over time and to determine whether one donor site gives a higher recipient bone density than the other. Methods A prospective study was performed evaluating 40 healthy patients with congenital cleft lip and palate undergoing secondary alveolar bone grafting, 20 (14 boys and 6 girls) having iliac crest and 20 (12 boys and 8 girls) receiving tibial bone grafts. Bone harvest and grafting was carried out by one operator (G.P.). Optical density of iliac and tibial grafts measured using a computerized densitometer, was compared at 6 days, 6 weeks, and 3 months. Due to interference from orthodontic appliances, optical density measurements for 16 subjects were not possible, and these patients were excluded from the study. The length of hospital stay postoperatively for both grafting procedures were recorded. Results A significant decrease in relative bone density was demonstrated during the 3-month postoperative period in both iliac and tibial bone graft groups (p < .05). The difference in densities between iliac crest and tibial groups were not significantly different at any of the time points (paired t test, p > .05). Subjects undergoing iliac crest grafts stayed an average of 5 days in the hospital postoperatively, compared with subjects with tibial grafts who stayed an average of 3 days postoperatively. Conclusion Optical density measurements of bone grafted into alveolar clefts, reported here for the first time, provide a valuable objective assessment of graft progress. Tibial and iliac crest grafts gave similar optical densities at recipient sites over the first 3 months. Iliac crest grafts required significantly longer postoperative stay; an important consideration in selecting donor sites for secondary bone grafting.

scholarly journals Sensitivity distribution of Venturia inaequalis to fenarimol in Québec apple orchards

2005 ◽  
Vol 75 (1) ◽  
pp. 35-43 ◽  
Author(s):  
O. Carisse ◽  
J.R. Pelletier
Keyword(s):  
Growth Inhibition ◽  
Frequency Distribution ◽  
Radial Growth ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Inhibition Assay ◽  
Baseline Sensitivity ◽  
Growth Inhibition Assay ◽  
Sensitivity Distribution ◽  
Ergosterol Synthesis

This study was initiated to quantify the baseline sensitivity of apple scab (Venturia inaequalis) to fenarimol, an ergosterol synthesis-inhibiting fungicide. In 1988, 576 monoconidial isolates of Venturia inaequalis were collected from 26 commercial orchards throughout Quebec. Sensitivity to fenarimol was assessed by radial growth inhibition assay. The ED50 values for the 26 orchards ranged from 0.024 to 5.212 (μ g mL-1 with a mean ED50 of 0.156 μg ml-1. Reduced sensitivity, expressed as ED50, was found in three orchards for an overall frequency of 4.51% of isolates. Sensitive isolates had a mean ED50 of 0.079 μg ml-1, whereas isolates with reduced sensitivity had a mean ED50 of 1.714 μ g mL-1, yielding a resistance factor of about 22. Four populations were identified based on the frequency distribution of ED50 values.

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