Induced and Natural Inhibitory Behavior of Milk and Significance to Antibiotic Disc Assay Testing

Eight strains of Ceratocystis ulmi originating from different locations and host species were found to be highly sensitive to the antibiotic myxin in in vitro tests. By paper disc assay, amounts as low as 0.5–1.0 μg caused strong inhibition of the fungus on solid media. The minimum inhibitory concentration in liquid culture was 0.2 μg/ml and levels of antibiotic above this concentration proved to be fungicidal.

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Evaluation of powdery mildew resistance in various melon (Cucumis melo L.) genotypes

Agricultural Science and Technology ◽

10.15547/10.15547/ast.2018.04.053 ◽

2018 ◽

Vol 10 (4) ◽

pp. 279-284

Author(s):

Zh. Ivanova ◽

K. Vasileva ◽

N. Velkov ◽

S. Grozeva

Keyword(s):

Powdery Mildew ◽

Genetic Resistance ◽

Leaf Disc ◽

Breeding Program ◽

Vegetable Crops ◽

Plant Materials ◽

South Central ◽

Leaf Disc Assay ◽

Disc Assay

Abstract. Powdery mildew, caused by Podosphaera xanthii and Golovinomyces cichoracearum, is an economically important disease in melon worldwide. Genetic resistance is one of the most suitable strategies to control powdery mildew. During the last few years several races of the pathogens have been reported. The need to develop resistant varieties is a challenge for each breeding program. Leaf disc assay was used in phytopathology and breeding programs as a rapid and reliable method for evaluation of disease resistance in a large number of plant materials. The purpose of this study was to establish species and races of powdery mildew in Plovdiv region, South Central Bulgaria; to develop a suitable system of pathogen isolation and cultivation; to determine the resistance levels in different melon genotypes available in Maritsa Vegetable Crops Research Institute (MVCRI) - Plovdiv collection by the leaf disc assay. Fifty-three melon genotypes, including lines, varieties, hybrids and ten differential lines were tested. The data showed that causal agent of powdery mildew was race 1 of P. xanthii in Plovdiv region. Our experimental results indicated that for the long-term storage of powdery mildew it is preferable to keep a whole plant under in vitro conditions. This allows the preservation of powdery mildew for two months before transferring on a new tissue. Thirty-four of the tested melon genotypes reacted as immune or resistant and nineteen as susceptible. Resistant melon genotypes are a suitable source in initiating a new breeding program aimed to increase resistance to powdery mildew.

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Enhanced Ex vivo drug sensitivity testing of chronic lymphocytic leukaemia using refined DiSC assay methodology

Leukemia Research ◽

10.1016/0145-2126(95)00127-1 ◽

1996 ◽

Vol 20 (2) ◽

pp. 143-153 ◽

Cited By ~ 29

Author(s):

Andrew G. Bosanquet ◽

Philip B. Bell

Keyword(s):

Chronic Lymphocytic Leukaemia ◽

Drug Sensitivity ◽

Lymphocytic Leukaemia ◽

Ex Vivo ◽

Sensitivity Testing ◽

Drug Sensitivity Testing ◽

Disc Assay

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Bacillus Stearothermophilus Disc Assay: A Review

Journal of AOAC International ◽

10.1093/jaoac/78.6.1408 ◽

1995 ◽

Vol 78 (6) ◽

pp. 1408-1415

Author(s):

Stanley E Katz ◽

Marie Siewierski

Keyword(s):

Bacillus Stearothermophilus ◽

Assay Development ◽

The Future ◽

Development Data ◽

History Of ◽

Disc Assay

Abstract The literature on the Bacillus stearothermophilus disc assay was reviewed and evaluated. The history of the assay development; data on applicability, sensitivity, interferences, and cowside screening; potential for the future; and limitations are presented and discussed.

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A detached petal disc assay and virus-induced gene silencing facilitate the study of Botrytis cinerea resistance in rose flowers

Horticulture Research ◽

10.1038/s41438-019-0219-2 ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

Xiaoqian Cao ◽

Huijun Yan ◽

Xintong Liu ◽

Dandan Li ◽

Mengjie Sui ◽

...

Keyword(s):

Jasmonic Acid ◽

Gene Silencing ◽

Botrytis Cinerea ◽

High Throughput ◽

Regulatory Protein ◽

Gray Mold ◽

Virus Induced Gene Silencing ◽

Potential Benefits ◽

Rose Petals ◽

Disc Assay

AbstractFresh-cut roses (Rosa hybrida) are one of the most important ornamental crops worldwide, with annual trade in the billions of dollars. Gray mold disease caused by the pathogen Botrytis cinerea is the most serious fungal threat to cut roses, causing extensive postharvest losses. In this study, we optimized a detached petal disc assay (DPDA) for artificial B. cinerea inoculation and quantification of disease symptoms in rose petals. Furthermore, as the identification of rose genes involved in B. cinerea resistance could provide useful genetic and genomic resources, we devised a virus-induced gene silencing (VIGS) procedure for the functional analysis of B. cinerea resistance genes in rose petals. We used RhPR10.1 as a reporter of silencing efficiency and found that the rose cultivar ‘Samantha’ showed the greatest decrease in RhPR10.1 expression among the cultivars tested. To determine whether jasmonic acid and ethylene are required for B. cinerea resistance in rose petals, we used VIGS to silence the expression of RhLOX5 and RhEIN3 (encoding a jasmonic acid biosynthesis pathway protein and an ethylene regulatory protein, respectively) and found that petal susceptibility to B. cinerea was affected. Finally, a VIGS screen of B. cinerea-induced rose transcription factors demonstrated the potential benefits of this method for the high-throughput identification of gene function in B. cinerea resistance. Collectively, our data show that the combination of the DPDA and VIGS is a reliable and high-throughput method for studying B. cinerea resistance in rose.

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Precision Parameters for AOAC Bacillus stearothermophilus Disc Assay Based on FDA Milk Laboratory Quality Assurance 1982–1986 Samples

Journal of Food Protection ◽

10.4315/0362-028x-52.12.867 ◽

1989 ◽

Vol 52 (12) ◽

pp. 867-870 ◽

Cited By ~ 1

Author(s):

J. T. PEELER ◽

J. W. MESSER ◽

G. A. HOUGHTBY ◽

J. E. LESLIE ◽

J. E. BARNETT

Keyword(s):

Quality Assurance ◽

Bacillus Stearothermophilus ◽

Penicillin G ◽

Test Results ◽

Inhibitory Substance ◽

Milk Samples ◽

Relative Standard ◽

Standard Deviations ◽

Estimate Precision ◽

Disc Assay

Inhibitory substance (antibiotic) test results from State Split Milk Samples were used to estimate precision parameters and to compare antibiotic medium 4 (A4) and PM indicator (PM) agars. Five inhibitory substances (ampicillin, cephapirin, erythromycin, neomycin, and penicillin-G) were tested. Repeatability relative standard deviations (RSDr) ranged from 1.0 to 4.8%, and the reproducibility relative standard deviations (RSDR) ranged from 4.8 to 10.4%. Zone sizes of erythromycin, neomycin, and penicillin-G were significantly larger on PM agar (α = 0.05) than on A4 agar. The reverse was observed for cephapirin. No difference between agars was noted for ampicillin.

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Determination of Residual Cephalexin in Chick Tissues by Bacillus stearothermophilus Paper Disc Assay

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/71.2.337 ◽

1988 ◽

Vol 71 (2) ◽

pp. 337-340

Author(s):

Junya Okada ◽

Ikuji Higuchi ◽

Sadao Kondo ◽

Bun-Ichi Saito

Keyword(s):

Detection Limit ◽

Trichloroacetic Acid ◽

Bacillus Stearothermophilus ◽

Test Organism ◽

Acid Extract ◽

Average Recovery ◽

Ad Libitum ◽

Paper Disc ◽

Disc Assay

Abstract A paper disc method is described for determination of residual cephalexin (CEX) in chick tissues. A trichloroacetic acid extract of plasma and tissues is chromatographed on a macroreticular resin (Diaion HP-20) column to remove endogenous antibacterial substances interfering with the assay. The eluate is evaporated to dryness and the residue, dissolved in methanol-water (1 + 2), is subjected to a paper disc assay using Bacillus stearothermophilus var. calidolactis C953 NIZO as a test organism. The detection limit was 0.0375 ppm in tissue; the average recovery of CEX ranged from 72.4% in skin to 90.4% in plasma. Water containing 200 or 500 mg/L of CEX was given ad libitum to 2-week-old chicks for 10 days; the highest levels of CEX were found in the kidney, and the lowest were found in muscle at 0 h of withdrawal. CEX disappeared from most tissues at 24 h after withdrawal except from skin of chicks given 500 mg/ L. However, the drug was not detected in the skin at 48 h after withdrawal.

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Shikimate Accumulation in Sunflower, Wheat, and Proso Millet after Glyphosate Application

Weed Science ◽

10.1614/ws-06-065.1 ◽

2007 ◽

Vol 55 (1) ◽

pp. 1-5 ◽

Cited By ~ 30

Author(s):

W. Brien Henry ◽

Dale L. Shaner ◽

Mark S. West

Keyword(s):

Leaf Disc ◽

Spectrophotometric Assay ◽

The Other ◽

Proso Millet ◽

Glyphosate Drift ◽

Leaf Disc Assay ◽

Disc Assay

Experiments were conducted to examine the utility of a spectrophometric leaf disc assay for detecting shikimate accumulation after glyphosate application in sunflower, proso millet, and wheat. The assay was conducted on both greenhouse- and field-grown plants. Glyphosate was applied at five rates ranging from 840 to 53 g ae ha−1. Shikimate accumulation data were generated at 1, 4, 7, and 14 d after application (DAA). Sunflower accumulated shikimate more rapidly and at lower glyphosate rates than the other two species. At 14 DAA, glyphosate at the two highest rates remained detectable in all three species. Plants receiving lower glyphosate doses (210, 105, and 53 g ae ha−1) had begun to grow out of the injury, or at least the shikimate levels in the plants were no longer significantly different than that present in the untreated controls. This spectrophotometric assay is both rapid and simple, with respect to other means of detecting shikimate, and it can be used to detect glyphosate drift. For it to be used by crop managers, samples from potentially drift-affected crops should be taken as soon as possible after the suspected drift event or immediately after the appearance of glyphosate injury.

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