Journal articles: 'Agar diffusion assay'

1

Rogers, Ann M., and Thomas J. Montville. "Improved agar diffusion assay for nisin quantification." Food Biotechnology 5, no. 2 (January 1991): 161–68. http://dx.doi.org/10.1080/08905439109549799.

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UNAL, R., H. P. FLEMING, R. F. McFEETERS, R. L. THOMPSON, F. BREIDT, and F. G. GIESBRECHT. "Novel Quantitative Assays for Estimating the Antimicrobial Activity of Fresh Garlic Juice†,‡." Journal of Food Protection 64, no. 2 (February 1, 2001): 189–94. http://dx.doi.org/10.4315/0362-028x-64.2.189.

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Novel agar diffusion and broth dilution assays were developed for quantitatively estimating the antimicrobial activity of fresh garlic juice. Bacteria found to be inhibited by garlic juice in agar diffusion assay included two gram-positive and five gram-negative species. Leuconostoc mesenteroides was not inhibited. Escherichia coli B-103 (HB101, with pJH101, ampicillin resistant, 100 μg ml−1) was inhibited and chosen as the standard culture for quantitative assays. The agar diffusion assay was based on the slope ratio method, where the slope of dose response for garlic juice was divided by the slope of dose response for methylmethane thiosulfonate (MMTSO2). Juice from fresh garlic varied in activity between 1.76 and 2.31 μg of MMTSO2 per mg of garlic juice. The activity of juice decreased during 11 months of storage of garlic cloves at 5°C from 2.31 to less than 0.1 μg of MMTSO2 per mg of juice. The broth dilution assay also used the E. coli B-103 culture, which permitted selective enumeration of this bacterium when 100 μg ml−1 of ampicillin was incorporated into the enumerating agar. Selective enumeration was essential since the garlic juice was not sterile and, thus, contained natural flora. Growth of E. coli was unaffected by 0.1%, delayed by 0.25%, and completely inhibited at 0.5 and 2% garlic juice in broth during 24 h of incubation at 37°C. The minimum inhibition concentration of garlic juice by broth dilution assay was, thus, estimated to be 0.5%, which is equivalent to 3.46 μg of MMTSO2 per mg of garlic juice by the agar diffusion assay.

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Nweze, E. I., P. K. Mukherjee, and M. A. Ghannoum. "Agar-Based Disk Diffusion Assay for Susceptibility Testing of Dermatophytes." Journal of Clinical Microbiology 48, no. 10 (July 28, 2010): 3750–52. http://dx.doi.org/10.1128/jcm.01357-10.

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TSAI, CHIN-EN, and FUSAO KONDO. "Improved Agar Diffusion Method for Detecting Residual Antimicrobial Agents." Journal of Food Protection 64, no. 3 (March 1, 2001): 361–66. http://dx.doi.org/10.4315/0362-028x-64.3.361.

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The improved agar diffusion method for determination of residual antimicrobial agents was investigated, and the sensitivities of various combinations of test organisms and assay media were determined using 7 organisms, 5 media, and 31 antimicrobial agents. Bacillus stearothermophilus and synthetic assay medium (SAM) showed the greatest sensitivity for screening penicillins (penicillin G and ampicillin). The combination of Bacillus subtilis and minimum medium (MM) was the most sensitive for tetracyclines (oxytetracycline and chlortetracycline), B. stearothermophilus and SAM or Micrococcus luteus and Mueller-Hinton agar (MHA) for detecting tylosin and erythromycin, B. subtilis and MHA for aminoglycosides (streptomycin, kanamycin, gentamicin, and dihydrostreptomycin), B. stearothermophilus and SAM for polyethers (salinomycin and lasalocid), and B. subtilis and MM or Clostridium perfringens and GAM for polypeptides (thiopeptin, enramycin, virginiamycin, and bacitracin). However, gram-negative bacterium Escherichia coli ATCC 27166 and MM were better for screening for colistin and polymixin-B. For detecting the synthetic drugs tested, the best combination was B. subtilis and MM for sulfonamides, E. coli 27166 and MM for quinolones (oxolinic acid and nalidixic acid), B. subtilis and MM for furans (furazolidone), and the bioluminescent bacterium Photobacterium phosphoreum and luminescence assay medium for chloramphenicol and oxolinic acid. The results showed that the use of four assay plates, B. stearothermophilus and SAM, B. subtilis and MM, M. luteus and MHA, and E. coli 27166 and MM, was superior to the currently available techniques for screening for residual antimicrobial agents in edible animal tissues.

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Zainab, Kashmala, and Hira Batool. "A Simplistic Screening Assay of Antimicrobial Compounds and Enzymatic Activity from Local Soil Microbes." RADS Journal of Biological Research & Applied Sciences 9, no. 1 (September 11, 2018): 24–29. http://dx.doi.org/10.37962/jbas.v9i1.118.

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Antibiotics production is the most emerging field worldwide with a constant need for the new ones to fight the microbial resistance. In this context, the research was pursued to isolate, characterize and screen for promising antibiotic-producing microbes from local soil. The soil bacterial isolates (S1, S2, S3,S4, and S5) and fungal isolates (F1, F2, F4, F6, and F7) were selected and screened for antimicrobial activity against the Test bacteria by agar well diffusion and disc diffusion methods. Assays for Extracellular enzymes including Protease, Lipase, Lecithinase, Cellulase, and Amylase following the substrate hydrolysis were performed on different Agars such as Casein Agar, Tween 80 Agar, Egg Yolk Agar, Carboxymethylcellulose Agar, and Starch Agar respectively. The isolated microorganisms which produced antimicrobial compounds were identified as Bacillus, Actinomycetes, Streptomycetes, H. werneckii, A. niger, A. flavus, A. fumigatus and P. notatum on the basis of their cultural and microscopic characteristics and their optimum growth. The antimicrobial activity was determined by varying pH and NaCl concentrations. The research work revealed that among all isolates Actinomycetes (21%), P. notatum (29%) and H. werneckii (21%) showed maximum bioactivities against the test organisms and all isolates exhibited at least four of the tested enzymes.

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Christensen, Thomas Elo, and Michael Weis Bentzon. "Quantitative Microbiological Assay of Thiomersal Using Agar Diffusion From Paper Discs." Acta Pathologica Microbiologica Scandinavica Section B Microbiology 87B, no. 1-6 (August 15, 2009): 265–69. http://dx.doi.org/10.1111/j.1699-0463.1979.tb02437.x.

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Loureno, Felipe Rebello, Telma Mary Kaneko, and Terezinha De Jesus Andreoli Pinto. "Validation of Erythromycin Microbiological Assay Using an Alternative Experimental Design." Journal of AOAC INTERNATIONAL 90, no. 4 (July 1, 2007): 1107–10. http://dx.doi.org/10.1093/jaoac/90.4.1107.

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Abstract The agar diffusion method, widely used in antibiotic dosage, relates the diameter of the inhibition zone to the dose of the substance assayed. An experimental plan is proposed that may provide better results and an indication of the assay validity. The symmetric or balanced assays (2 2) as well as those with interpolation in standard curve (5 1) are the main designs used in the dosage of antibiotics. This study proposes an alternative experimental design for erythromycin microbiological assay with the evaluation of the validation parameters of the method referring to linearity, precision, and accuracy. The design proposed (3 1) uses 3 doses of standard and 1 dose of sample applied in a unique plate, aggregating the characteristics of the 2 2 and 5 1 assays. The method was validated for erythromycin microbiological assay through agar diffusion, revealing its adequacy to linearity, precision, and accuracy standards. Likewise, the statistical methods used demonstrated their accordance with the method concerning the parameters evaluated. The 3 1 design proved to be adequate for the dosage of erythromycin and thus a good alternative for erythromycin assay.

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Solano, Ana Gabriela Reis, Larissa de Melo Campos Sousa Pereira, Míriam de Fátima Vianna Leonel, and Elzíria de Aguiar Nunan. "Development of agar diffusion method for dosage of gramicidin." Brazilian Journal of Pharmaceutical Sciences 47, no. 3 (September 2011): 564–72. http://dx.doi.org/10.1590/s1984-82502011000300014.

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Gramicidin, an antimicrobial peptide active against Gram positive bacteria, is commonly used in pharmaceutical preparations for topical use. Considering that only the turbidimetric method has been described in the literature, the present study sought to develop and validate an agar diffusion method for the dosage of gramicidin. The method was developed and validated using the Kocuria rhizophila ATCC 9341 as a test microorganism. Two designs were used: a 3x3 parallel-line model, and a 5x1 standard curve. The validation demonstrated that the method follows the linear model (r²= 0.994), presenting a significant regression between the zone diameter of growth inhibition and the logarithm of the concentration within the range of 5 to 25.3 µg/mL. The results obtained for both designs were precise, having a relative standard deviation (R.S.D.) for intra-day precision of 0.81 for the 3x3 assay and 1.90 for the 5x1 assay. For the inter-day precision, the R.S.D. was 1.35 for the 3x3 and 2.64 for the 5x1. The accuracy was verified and results confirmed to be accurate, having a tolerance interval of 95%, which lay within permitted limits and appropriate trueness. In addition, the method was considered selective, with limit of detection and upper and lower limits of quantification of 2.00, 5.00 and 25.3 µg/mL, respectively. No difference in precision between the designs used in the agar diffusion method was evident (p>0.05). The method proved to be appropriate for the microbiological dosage of the raw material gramicidin.

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Renard, Laurent, Gerard Moulin, and Pascal Sanders. "Using Experimental Design To Optimize a Microbial Diffusion Assay." Journal of AOAC INTERNATIONAL 75, no. 6 (November 1, 1992): 1045–48. http://dx.doi.org/10.1093/jaoac/75.6.1045.

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Abstract As a prerequisite to validation of the cylinder plate diffusion assay for the antibiotic colistin sulfate in plasma, the assay needed to be optimized. Bordetella bronchiseptica (ATCC 4617) was the test organism for optimization. Ionic strength of buffer, quantity of test organism, duration of prediffusion, and volume of agar layer were studied. The effects of each factor were examined according to an experimental design. A 4 h prediffusion at 4°C increased sensitivity. Repeatability was improved by using 100 mL agar per bioassay dish, dilution of the plasma with buffer (3 + 1), and prediffusion. The slope of the standard response line was steeper with prediffusion. The reduced quantity of test organism contributed to better sensitivity and good repeatability. No significant interaction between these factors was found. Experimental designs were used successfully to rapidly set up a microbial method requiring a limited number of runs

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Shin, Sung Heui, Yong Lim, Shee Eun Lee, Nam Woong Yang, and Joon Haeng Rhee. "CAS agar diffusion assay for the measurement of siderophores in biological fluids." Journal of Microbiological Methods 44, no. 1 (February 2001): 89–95. http://dx.doi.org/10.1016/s0167-7012(00)00229-3.

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11

Burres, Neal S., Janet E. Hunter, and Amy E. Wright. "A Mammalian Cell Agar-Diffusion Assay for the Detection of Toxic Compounds." Journal of Natural Products 52, no. 3 (May 1989): 522–27. http://dx.doi.org/10.1021/np50063a010.

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12

Chiu, Chien-Tung, Chung-Hsu Lai, Yi-Han Huang, Chih-Hui Yang, and Jiun-Nong Lin. "Comparative Analysis of Gradient Diffusion and Disk Diffusion with Agar Dilution for Susceptibility Testing of Elizabethkingia anophelis." Antibiotics 10, no. 4 (April 16, 2021): 450. http://dx.doi.org/10.3390/antibiotics10040450.

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Elizabethkingia anophelis has recently emerged as a cause of life-threatening infections. This study compared the results of antimicrobial susceptibility testing (AST) conducted for E. anophelis through different methods. E. anophelis isolates collected between January 2005 and June 2019 were examined for their susceptibility to 14 antimicrobial agents by using disk diffusion, gradient diffusion (Etest; bioMérieux S.A., Marcy l’Etoile, France), and agar dilution methods. The agar dilution method was the reference assay. According to the agar dilution method, the isolates exhibited the highest susceptibility to minocycline (100%), doxycycline (97.6%), rifampin (95.2%), and levofloxacin (78.6%). A very major error rate of >1.5% was observed for nine antibiotics tested using the disk diffusion method. The overall categorical agreement rate between the disk diffusion and agar dilution methods was 74.8%, and ceftazidime, minocycline, levofloxacin, and rifampin met the minimum requirements for discrepancy and agreement rates. The Etest method tended to produce lower log2 minimum inhibitory concentrations for the antibiotics, except for trimethoprim–sulfamethoxazole and rifampin; the method resulted in very major errors for nine antibiotics. The overall essential and categorical agreement rates between the Etest and agar dilution methods were 67.3% and 76.1%, respectively. The Etest method demonstrated acceptable discrepancy and agreement rates for ceftazidime, minocycline, doxycycline, levofloxacin, and rifampin. AST results obtained through the disk diffusion and Etest methods for multiple antibiotics differed significantly from those obtained using the agar dilution method. These two assays should not be a routine alternative for AST for E. anophelis.

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Mat Jalil, Mohd Taufiq, Nabila Husna Hairudin, and Darah Ibrahim. "Muscodor sp. IBRL OS-94, A Promising Endophytic Fungus of Ocimum sanctum with Antimicrobial Activity." Pharmaceutical Sciences 27, no. 2 (October 2, 2020): 268–80. http://dx.doi.org/10.34172/ps.2020.79.

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Background: An endophytic fungus, Muscodor sp. IBRL OS-94 isolated from the leaf of Ocimum sanctum was believed to possess significant antimicrobial activity and several assays were carried out to evaluate its pharmaceutical potential. Methods: Agar plug diffusion and the disk diffusion assays were performed to evaluate the antimicrobial activity of the fungal extract. Also, the broth microdilution assay was done to investigate the minimum inhibitory concentration (MIC) of the fungal extract. Meanwhile, the scanning electron microscope (SEM) was employed to observe the structural degeneration of the microbial cells treated to the extract. Results: The results revealed that fungal isolate showed favorable antimicrobial activity through agar plug diffusion assay and the disk diffusion assay demonstrated that most of the test microorganisms were susceptible to extracellular extract compared to extracellular extract. As for the MIC and MLC values, the extracellular fungal extract exerted a bactericidal/fungicidal effect against all five Gram-positive bacteria, four Gram-negative bacteria, one yeast, and none of the test fungi. Meanwhile, the intracellular fungal extract exhibited bactericidal/fungicidal activity against three Gram-positive bacteria, one Gram-negative bacterium, and one yeast. The structural degeneration study via SEM revealed that various cell abnormalities including severe damage to the cell wall which led to microbial cell death. Conclusion: The present study suggests the fungal extract from Muscodor sp. IBRLOS-94 as an antimicrobial agent.

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Yamamoto, Célia H., and Terezinha J. A. Pinto. "Rapid Determination of Neomycin by a Microbiological Agar Diffusion Assay Using Triphenyltetrazolium Chloride." Journal of AOAC INTERNATIONAL 79, no. 2 (March 1, 1996): 434–40. http://dx.doi.org/10.1093/jaoac/79.2.434.

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Abstract The standard, quantitative determination of neomycin activity by the agar diffusion method requires an 18 to 24 h incubation time. To reduce incubation time, an alternative method using triphenyltetra- zolium chloride has been developed. The inhibition zoneappears much earlier; hence, an effort was made to standardize it. This indicator develops a physical response, related to the biological one, after a determined period. A Staphylococcus epidermidis suspension inoculated into solid medium ata concentration low enough that growth is not visible can reduce the dye to formazan. There is enough contrast to read the inhibition zone optically after a7 h incubation. There is no significant difference between standard curves for 7 and 24 h incubations.Comparative assays for some pharmaceutical drugs containing neomycin in different forms show that it is possible to reduce incubation time. This modification is valid because no dispersion of results was detected by statistical analysis, which indicates that they belong to the same population. Thus, a rapid microbiological assay of neomycin has been validated and standardized

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VENTURINI, M. E., D. BLANCO, and R. ORIA. "In Vitro Antifungal Activity of Several Antimicrobial Compounds against Penicillium expansum." Journal of Food Protection 65, no. 5 (May 1, 2002): 834–39. http://dx.doi.org/10.4315/0362-028x-65.5.834.

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Fungicides used in the prevention and control of mold rots in stored apples are subjected to legal, social, and biological limitations. The aim of this study was to find an alternative to postharvest fungicides currently used in the prevention and control of blue mold rot caused by Penicillium expansum in apples. For this purpose, the antimicrobial activity and MIC of several substances against P. expansum were evaluated in vitro using different end point methods: agar diffusion assay, volatility method, and agar dilution and broth dilution MIC assays. Most of the substances tested are common food ingredients and have a recognized antimicrobial activity. Essential oils, such as thymol, eugenol, citral and cineole, vanillin, sodium hypochlorite, acetic acid, potassium sorbate, and hydrogen peroxide, were the substances evaluated. Thymol and citral were the essential oil components that showed the greatest inhibitory effects. The effectiveness of 5 and 10% hydrogen peroxide in growth inhibition of P. expansum in the agar diffusion assay was total, and its MIC as determined by the agar and broth dilution assays was less than 0.025%. These results indicate that the application of small quantities of hydrogen peroxide to the apple skin might be an alternative to fungicides in the elimination of P. expansum.

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Brady, Marietta Sue, and Stanley E. Katz. "Factors Influencing Optimization of Diffusion Assays for Antibiotics." Journal of AOAC INTERNATIONAL 73, no. 2 (March 1, 1990): 202–5. http://dx.doi.org/10.1093/jaoac/73.2.202.

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Abstract Agar nutrient content, cylinder charge volume, thickness (volume) of the agar layer, and incubation temperature were 4 factors varied to determine their effect(s) on the optimization of the cylinder-plate diffusion assay. Chlortetracycline was the pilot antibiotic and Bacillus cereus was used as the assay organism. Zones of inhibition were larger when the incubation temperature was lower than that which was commonly used and/or when the nutrient level was decreased; the zones were smaller when the incubation temperature was raised and/or when an increased nutrient level was used. The thickness (volume) of the assay layer played the most important role; the thinner the layer the less the effect the cylinder charge volume had on the zone diameter. The slopes of the response lines were minimally affected by cylinder charge volume. For a 7 mL assay layer per standard Petri plate, cylinder charge volumes ranging from 150 to 250 μL had little effect on zone diameter. The linearity of the response line was unaffected by assay layer thickness (volume), nutrient level, temperature of Incubation, or cylinder charge volume. As long as the conditions for the assay were standardized, there were no discernible effects on recoveries or potencies.

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Abdul Rahman, Kharul Azmi Muazzam, and Darah Ibrahim. "Antimicrobial activity of endophytic fungi isolated from different plant parts of Curcuma mangga Valeton and Zijp." Journal of Tropical Resources and Sustainable Science (JTRSS) 9, no. 1 (August 22, 2021): 37–42. http://dx.doi.org/10.47253/jtrss.v9i1.707.

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The endophytic fungi isolated from different plant parts including leaf, stem and rhizome of Curcuma mangga were screened for antimicrobial activity by employing agar plug diffusion assay and disc diffusion assay for primary screening and secondary screening, respectively. A total of 127 endophytic fungi that were successfully isolated from various plant parts were cultured to examine their antimicrobial activities. Qualitative screening using agar plug diffusion assay revealed that 118 isolates (92.9%) showed antimicrobial activity against at least on one test microorganisms and suggested that the rhizome part exhibited the highest percentage of antiyeast (58.3%) and antifungal (91.7%) activities compared to leaf and stem parts. Quantitative screening using disc diffusion assay indicated that ethyl acetate extract from fermentative broth (extracellular compound) demonstrated better antimicrobial activity compared to methanol extract derived from fungal biomass (intracellular compound) against all the four classes of pathogenic microorganisms tested (Gram-positive bacteria, Gram-negative bacteria, yeast and fungi). The future of endophytic fungus study is very promising as it possesses hidden potential to be developed as natural antimicrobial agent.

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Schmidt, Cleber A., Marcelly Carazzo, Luciane V. Laporta, Celso F. Bittencourt, Marcos R. Santos, and Milene Friedrich. "Development and Validation of an Agar Diffusion Assay for Determination of Ceftazidime in Pharmaceutical Preparations." Journal of AOAC INTERNATIONAL 91, no. 1 (January 1, 2008): 59–66. http://dx.doi.org/10.1093/jaoac/91.1.59.

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Abstract Ceftazidime (CFZ) is a broad spectrum parenterallactam antibiotic of the cephalosporin family. This paper reports the development and validation of an agar diffusion microbiological assay using the cylinder-plate method for determination of CFZ in powder for injection. The validation carried out yielded good results in terms of linearity, precision, accuracy, selectivity, and robustness. The assay is based on the inhibitory effect of CFZ upon the strain of Pseudomonas aeruginosa ATCC 27853 used as the test microorganism. The results of the assays were treated statistically by analysis of variance and were found to be linear (correlation coefficient = 0.999998) in the selected range of 8.032.0 g/mL; precise [repeatability: relative standard deviation (RSD) = 1.11; intermediate precision: between-day RSD = 1.37 and between-analyst RSD = 1.41]; and accurate. The selectivity of the bioassay was evaluated by analysis of degraded samples at 50C, and the results were compared with a pharmacopeial liquid chromatographic method at the time 0, 24, and 48 h. The results demonstrated the validity of the proposed bioassay, which allows reliable quantitation of CFZ in pharmaceutical samples and can be used as a useful alternative methodology for CFZ analysis in routine quality control.

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Lourenço, Felipe Rebello, and Terezinha de Jesus Andreoli Pinto. "Comparison of three experimental designs employed in gentamicin microbiological assay through agar diffusion." Brazilian Journal of Pharmaceutical Sciences 45, no. 3 (September 2009): 559–66. http://dx.doi.org/10.1590/s1984-82502009000300022.

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Gentamicin is a broad-spectrum antibiotic complex produced by actinomycetes belonging to Micromonospora genus and classified among aminoglycoside antibiotics, used in the treatment of serious infections derived from Gram-negative microorganisms. Alterations of their antimicrobial activity not shown in chemical assays can be evaluated through microbiological assays. The aim of this work was to compare 5 x 1, 2 x 2 and 3 x 1 experimental designs, evaluating validation parameters of specificity, linearity, range, precision, and accuracy for each experimental design in different levels of concentration, presentation, and lots. It consisted of 81 assays (in 3 replicas) of gentamicin microbiological dosage. The concentrations of the solutions used were employed in a range from 1.0 μg/mL to 5.0 μg/mL, diluted in phosphate buffer 0.1 M pH 8.0. Antibiotic medium number 11 was used, with Staphyloccocus epidermis (ATCC 12228). 21ml of medium were used as base layer and 4 ml of medium inoculated at 1% were used as surface layer. The dishes were incubated for 18 hours at 37 ± 1 ºC. The three designs employed showed adequate specificity for analysis of dermatological cream and injectable solution containing gentamicin sulphate. They also showed accuracy and linearity in the range evaluated, but not a significant difference concerning precision. The results were compared by means of the determination of the rates of measurement system capacity. The statistical analysis demonstrated that there is no significant difference among the results obtained through 5 x 1, 2 x 2, and 3 x 1, being these equivalent and interchangeable.

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MCCANN, TIM, TRISH EGAN, and GEORGE H. WEBER. "Assay Procedures for Commercial Probiotic Cultures." Journal of Food Protection 59, no. 1 (January 1, 1996): 41–45. http://dx.doi.org/10.4315/0362-028x-59.1.41.

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A number of commercially available cultures, marked for human consumption, were analyzed for viability using a resuspension medium consisting of KH2PO4, Na2HPO4, cysteine, Tween 80, agar, and an antifoam agent together with modifications of multiple-layer diffusion techniques. These methods were compared to the use of MRS plus cysteine, acidified MRS, and M17 culture media and found to be superior in the selection and enumeration of dried cultures of mixed genera.

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Huang, Tsui-Hsien, Chih-Lin Chen, Chi-Jr Hung, and Chia-Tze Kao. "Comparison of antibacterial activities of root-end filling materials by an agar diffusion assay and Alamar blue assay." Journal of Dental Sciences 7, no. 4 (December 2012): 336–41. http://dx.doi.org/10.1016/j.jds.2012.05.001.

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Fisher, Kevin J., Jeremy A. Turkett, Ashley E. Corson, and Kevin L. Bicker. "Peptoid Library Agar Diffusion (PLAD) Assay for the High-Throughput Identification of Antimicrobial Peptoids." ACS Combinatorial Science 18, no. 6 (May 26, 2016): 287–91. http://dx.doi.org/10.1021/acscombsci.6b00039.

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Abneuf, Mohammed A., Abiramy Krishnan, Marcelo Gonzalez Aravena, Ka-Lai Pang, Peter Convey, Nuradilla Mohamad-Fauzi, Mohammed Rizman-Idid, and Siti Aisyah Alias. "Antimicrobial activity of microfungi from maritime Antarctic soil." Czech Polar Reports 6, no. 2 (July 1, 2016): 141–54. http://dx.doi.org/10.5817/cpr2016-2-13.

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The search for cold-adapted and cold-active fungi in extreme environments provides the potential for discovering new species and novel bioactive compounds. In this study, soil samples were collected from Deception Island, Wilhelmina Bay (north-west Antarctic Peninsula, Graham Land) and Yankee Bay (Greenwich Island), maritime Antarctica, for the isolation of soil fungi and determination of their antimicrobial activity. The soil-plate method, agar block, disc diffusion and broth micro-dilution assays were applied to characterize the thermal classes and antimicrobial activity of the isolated fungi. A total of 27 isolates of fungi were obtained from 14 soil samples, including 13 Ascomycota, 4 Zygomycota and 10 anamorphic fungi. Cold-active (psychrotolerant) fungi predominated over cold-adapted (psychrophilic) fungi. In the antimicrobial assay, 16 isolates showed substantial inhibitory activity against test bacterial pathogens. Ethyl acetate extracts of 10 competent isolates showed significant inhibition of bacterial pathogens. Antifungal activity was observed in the disc diffusion assay, but not in the agar block assay. Minimum inhibitory, bactericidal and fungicidal concentrations were determined using the broth micro-dilution method, with an average in the range of 0.78-25 mg ml-1 on the test microorganisms. Isolate WHB-sp. 7 showed the best broad spectrum antimicrobial activity, with the potential for biotechnological studies in antibiotic development.

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Khan, Muhammad Rafiullah, Vanee Chonhenchob, Chongxing Huang, and Panitee Suwanamornlert. "Antifungal Activity of Propyl Disulfide from Neem (Azadirachta indica) in Vapor and Agar Diffusion Assays against Anthracnose Pathogens (Colletotrichum gloeosporioides and Colletotrichum acutatum) in Mango Fruit." Microorganisms 9, no. 4 (April 14, 2021): 839. http://dx.doi.org/10.3390/microorganisms9040839.

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Microorganisms causing anthracnose diseases have a medium to a high level of resistance to the existing fungicides. This study aimed to investigate neem plant extract (propyl disulfide, PD) as an alternative to the current fungicides against mango’s anthracnose. Microorganisms were isolated from decayed mango and identified as Colletotrichum gloeosporioides and Colletotrichum acutatum. Next, a pathogenicity test was conducted and after fulfilling Koch’s postulates, fungi were reisolated from these symptomatic fruits and we thus obtained pure cultures. Then, different concentrations of PD were used against these fungi in vapor and agar diffusion assays. Ethanol and distilled water were served as control treatments. PD significantly (p ≤ 0.05) inhibited more of the mycelial growth of these fungi than both controls. The antifungal activity of PD increased with increasing concentrations. The vapor diffusion assay was more effective in inhibiting the mycelial growth of these fungi than the agar diffusion assay. A good fit (R2, 0.950) of the experimental data in the Gompertz growth model and a significant difference in the model parameters, i.e., lag phase (λ), stationary phase (A) and mycelial growth rate, further showed the antifungal efficacy of PD. Therefore, PD could be the best antimicrobial compound against a wide range of microorganisms.

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Donga, Savan, Pooja Moteriya, and Sumitra Chanda. "EVALUATION OF ANTIMICROBIAL AND SYNERGISTIC ANTIMICROBIAL PROPERTIES OF PTEROCARPUS SANTALINUS." Asian Journal of Pharmaceutical and Clinical Research 10, no. 11 (November 1, 2017): 204. http://dx.doi.org/10.22159/ajpcr.2017.v10i11.20939.

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Objectives: The aim of the present study was to evaluate antibacterial and synergistic antimicrobial properties of leaf, stem and bark of Pterocarpus santalinus. Methods: The extraction was done by decoction method. The antimicrobial activity was done by agar well diffusion assay and the synergistic antimicrobial activity was done by agar disc diffusion assay. Results: The synergistic activity was studied with plant extracts plus antibiotics viz. Ampicillin , Polymyxin-B, Clotrimazole and Fluconazole. Conclusions: Amongst the three parts, the best antimicrobial activity was shown by bark extract. All the three parts showed synergistic antimicrobial activity with antibiotics but their level varied. The results suggest that all the three parts phytochemicals that enhance the antimicrobial efficacy of the antibiotics against some microorganisms and hence can be developed as a new therapeutic weapon against infectious diseases.

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King, Thea, Gary Dykes, and Ruth Kristianti. "Comparative Evaluation of Methods Commonly Used to Determine Antimicrobial Susceptibility to Plant Extracts and Phenolic Compounds." Journal of AOAC INTERNATIONAL 91, no. 6 (November 1, 2008): 1423–29. http://dx.doi.org/10.1093/jaoac/91.6.1423.

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Abstract A comparison was made to evaluate the ability of the most commonly used qualitative agar diffusion methods and a quantitative broth dilution assay to determine the antimicrobial activity of a plant extract and a variety of phenolic compounds. A disc and well diffusion technique and a microtiter broth microdilution (MBM) assay were used as antimicrobial susceptibility tests of a plant extract and several phenolic compounds against 7 bacterial species. In both the well and disc diffusion assays, the level of reproducibility was poor and a linear or logarithmic relationship did not exist between inhibition zone size and the concentration of the agents. The MBM method produced the most consistent results and allowed the determination of the relative sensitivities of each species and the relative antimicrobial activities of each agent. This study demonstrated that when a diffusion method is used, multiple concentrations of the agent must be assayed to ensure that a relationship exists between the concentration of the agent and inhibition zone size. When a relationship does not exist, antimicrobial activity should be determined by a quantitative dilution technique.

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Separovic, Luciana, Maria Luiza de Godoy Bertanha, Alessandro Morais Saviano, and Felipe Rebello Lourenço. "Conformity Decisions Based on Measurement Uncertainty—a Case Study Applied to Agar Diffusion Microbiological Assay." Journal of Pharmaceutical Innovation 15, no. 1 (February 1, 2019): 110–15. http://dx.doi.org/10.1007/s12247-019-09374-8.

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Khairuddin, Nozieana, Ida Idayu Muhamad, Wan Aizan Wan Abdul Rahman, and Bazlul Mobin Siddique. "Microbial study of pH sensitive starch based film using agar diffusion method (zone inhibition assay)." IOP Conference Series: Materials Science and Engineering 607 (August 30, 2019): 012007. http://dx.doi.org/10.1088/1757-899x/607/1/012007.

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Sabri, Gulnaaz, and Vimala Y. "ANTIBACTERIAL AND ANTIOXIDANT ACTIVITY OF LEUCAS ASPERA FLOWERS FROM BIHAR, INDIA." Asian Journal of Pharmaceutical and Clinical Research 11, no. 2 (February 1, 2018): 223. http://dx.doi.org/10.22159/ajpcr.2018.v11i2.21976.

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Objective: The aim of this study was to explicate antibacterial, antifungal, and antioxidant activities of Leucas aspera flowers.Methods: Antibacterial activity was done by agar diffusion method. The ethyl acetate extract of L. aspera flower was evaluated against both Gram-positive and Gram-negative bacteria. Antifungal activity was also done by agar diffusion method. The agar used for antifungal activity was Czapek Dox Agar. Nitric oxide scavenging assay and free radical scavenging assay were used for the antioxidant activity. Griess reagent was used in nitric oxide scavenging assay. 1,1-diphenyl-2-picryl hydrazyl was used in free radical scavenging assay.Results: L. aspera flower extract showed good antibacterial activity with the highest zone of inhibition against Vibrio cholera with 23 mm followed by Bacillus polymyxa showing 20 mm zone of inhibition. The ethyl acetate extract of L. aspera flower showed quite a good results with the highest inhibitory activity against Aspergillus niger with 13 mm zone of inhibition and lowest for Trichoderma viridae with 5 mm zone of inhibition. Antioxidant activity of L. aspera flower extract was done by free radical scavenging assay and nitric oxide scavenging assay. Nitric oxide scavenging assay showed prominent results almost performed equal to standard compound Butylated hydroxyl anisole (BHA) The values for 10 μl of L. aspera extract was 50.27, for the standard (BHA) showed 50.81. L. aspera extract values for 50 μl was 69.73 and for BHA, the values was 77.30. For 100 μl, the extract gave 82.70, and for standard BHA, the reading was 89.73.Conclusion: The results showed that L. aspera flower has broad-spectrum antibacterial activity ranging from 23 to 13 mm zone of inhibition. L. aspera flower has strong antioxidative power on nitric oxide radicals. The medicinal properties of plant species have made an outstanding contribution to the origin and evolution of many traditional herbal therapies.

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WALTRICH, K. K., J. HOSCHEID, and I. S. PROCHNAU. "Antimicrobial activity of crude extracts and fractions of Vernonia polyanthes Less (assa-peixe) flowers." Revista Brasileira de Plantas Medicinais 17, no. 4 suppl 2 (2015): 909–14. http://dx.doi.org/10.1590/1983-084x/14_110.

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ABSTRACT Vernonia polyanthes, known as “assa-peixe”, is a plant native to Brazil, and the decoction or infusion of its flowers, roots and leaves are used in folk medicine, being considered sources of diuretic, balsamic, anti-rheumatic substances, and are used in cases of bronchitis and persistent cough. The aim of the study was to evaluate the antimicrobial activity of the extract/fractions obtained by methanol maceration and infusion of V. polyanthes flower, also including qualitative identification of flower compounds, through phytochemical evaluation, using colorimetric tests. Identification tests for the presence of anthraquinones, tannins, flavonoids, saponins and alkaloids were performed. Microbiological evaluation was made through agar diffusion assay, using Escherichia coli, Staphylococcus aureus and Pseudomonasaeruginosa as test organisms. From the performed colorimetric tests it was possible to verify the presence of tannins and flavonoids in both extracts. Alkaloids were also observed in the macerated extract. The ethyl acetate fraction from the agar diffusion assay, from both extracts, presented microbial activity over Staphylococcus aureus. It was possible to qualitatively identify the floral compounds, and to show the differences between extraction methods, being methanol considered the best solvent to the extraction.

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Ngeufa Happi, Emmanuel, Simone Véronique Fannang, Marie Fomani, Suzye Mireille Moladje Donkwe, Nkoungou Yomzak Carine Nicaise, Jean Duplex Wansi, and Norbert Sewald. "Steroids and Ceramide from the Stem Bark of Odyendyea gabonensis." Zeitschrift für Naturforschung B 68, no. 8 (August 1, 2013): 924–30. http://dx.doi.org/10.5560/znb.2013-3132.

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Two new steroids, 22E, 24R-stigmast-22-ene-3,6,11-trione (1) and 22E, 24R-3-acetylstigmasta- 5,22-diene-7,11-dione (2), and one new ceramide, (2S,3S,4R,5R) N-(1,3,4,5-tetrahydroxyundecan- 2-yl)tetradecanamide (7), together with eleven known compounds were isolated from the CH2Cl2 extract of the stem bark of Odyendyea gabonensis. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral (EI and ESI) data, chemical reactions, and comparison with previously known analogs. Pure compounds were tested for their activity against the bacteria Bacillus subtilis, Staphylococcus aureus and Escherichia coli, the fungi Mucor miehei and Candida albicans, and the plant pathogen oomycetes Aphanomyces cochlioides, Pythium ultimum and Rhizoctonia solani using the paper disk agar diffusion assay. For active compounds, MICs were determined by the broth microdilution assay. Cytotoxic activity against the human lung adenocarcinoma cell line A 549 was evaluated by the MTT assay. All compounds delivered low to missing antimicrobial activities in the agar diffusion assay and MICs > 1 μg mL-1. The alkaloids 10 and 11 displayed cytotoxic activity against the human lung adenocarcinoma cell line A549 with IC50 2.5 and 4:5 μm respectively.

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Khadka, Sundar, Jeevan Sherchand, Bharat Pokhrel, Subhash Dhital, Rosham Manjhi, and Basistha Rijal. "Antifungal Susceptibility Testing of Dermatophytes by Agar Based Disk Diffusion Assay in Tertiary Care Hospital, Nepal." Microbiology Research Journal International 19, no. 2 (January 10, 2017): 1–5. http://dx.doi.org/10.9734/mrji/2017/31827.

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Saviano, Alessandro Morais, and Felipe Rebello Lourenço. "Using image analysis to determine gentamicin potency by agar diffusion microbiological assay and its measurement uncertainty." Measurement 146 (November 2019): 315–21. http://dx.doi.org/10.1016/j.measurement.2019.06.041.

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Scheven, M., and C. Scheven. "Quantitative screening for fluconazole-amphotericin B antagonism in severalCandida albicansstrains by a comparative agar diffusion assay." Mycoses 39, no. 3-4 (March 1996): 111–14. http://dx.doi.org/10.1111/j.1439-0507.1996.tb00111.x.

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Masanto, ,., ,. Parwito, Arif Wibowo, and Siti Subandiyah. "Molecular and Biochemical Detection of Fusarium Oxysporum f.sp. cubense as the Pathogen of Fusarium Wilt Disease on Banana (Musa spp.)." Jurnal Hortikultura Indonesia 1, no. 1 (April 6, 2014): 40. http://dx.doi.org/10.29244/jhi.1.1.40-45.

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ABSTRACT Molecular and biochemical characteristics of Fusarium oxysporum f.sp. cubense (Foc) were detected. Six of Indonesian Foc isolates were artificially inoculated on “Ambon Kuning” banana. DNA of one-week culture isolates was extracted by three methods prior to PCR assay using Foc TR4 (tropical race 4) specific primer. Activity of extracellular enzyme was determined with reduction sugar, agar diffusion and SDS-PAGE assays. Statistical analysis revealed that all isolates insignificantly caused Fusarium wilt symptoms on tested banana with disease severity index ranging from 3 to 3.6. Maximum DNA concentration was obtained by CTAB method (766.25 µg mL-1), followed by SDS and alkaline l ysis methods, i.e. 553.75 and 211.25 µg mL-1, respectively. PCR analysis showed that Bnt2 and Kjg1 isolates positively reacted to TR4 of Foc primer (DNA size of 1400 bp approximately). Reduction sugar and agar diffusion assays demonstrated that Kjg1 isolate significantly produced more extracellular enzyme, with 6.53 × 10-2mg mL-1 in conce ntration and 20 mm in halo diameter. Meanwhile, SDS-PAGE assay viewed diverse bands of tested fungi (20.6 to 80 kDa), representing four extracellular enzymes. Positive PCR results highlighted the presence of Foc TR4 infecting banana in Indonesia. Various activities of extracellular enzymes did not influence the pathogenicity of Foc.Key words: pathogenicity, DNA concentration, extracellular enzyme

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Hunaiti, A. "Radial Diffusion as a Simple and Rapid Method for Screening Superoxide Dismutase Activity." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 24, no. 5 (September 1987): 511–12. http://dx.doi.org/10.1177/000456328702400515.

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Superoxide dismutases are of great interest due to their increasing medical applications in therapy and diagnosis of some diseases. The radial diffusion assay was evaluated for its usefulness as a simple, cheap and accurate assay for screening superoxide dismutase activity. In this assay O2− radicals were generated from the interaction of reduced riboflavin with molecular oxygen upon exposure of agar gel containing riboflavin and N,N,N̄,N̄-tetramethylethylene diamine (TEMED) to light. If nitrotctrazolium dye is also present, it will be reduced to the blue insoluble formazan, whilst if superoxide dismutase is present it will prevent this blueing.1 The developed assay was found to give reproducible estimates of pure samples of superoxide dismutase with a lower limit of measurements of about 10 mg. It can be adapted to measure the levels of superoxide dismutase in various crude biological samples.

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Krauss, Jürgen, Ursula Kopp, and Franz Bracher. "Short microwave-assisted modular synthesis of naturally occurring oxygenated bibenzyls." Zeitschrift für Naturforschung B 70, no. 9 (September 1, 2015): 637–41. http://dx.doi.org/10.1515/znb-2015-0047.

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AbstractThe naturally occurring oxygenated bibenzyls lunularin and m-O-methyllunularin were prepared in a modular synthesis in four steps from two appropriate iodophenols and trimethylsilylacetylene utilizing microwave-assisted Sonogashira couplings as the crucial steps. The antimicrobial activity of the resulting natural products was evaluated in an agar diffusion assay.

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Quan, Hua, Ying-Ying Cao, Zheng Xu, Jing-Xia Zhao, Ping-Hui Gao, Xiao-Feng Qin, and Yuan-Ying Jiang. "Potent In Vitro Synergism of Fluconazole and Berberine Chloride against Clinical Isolates of Candida albicans Resistant to Fluconazole." Antimicrobial Agents and Chemotherapy 50, no. 3 (March 2006): 1096–99. http://dx.doi.org/10.1128/aac.50.3.1096-1099.2006.

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ABSTRACT In vitro interaction of fluconazole and berberine chloride was investigated against 40 fluconazole-resistant clinical isolates of Candida albicans. Synergism in fungistatic activity was found with the checkerboard microdilution assay. The findings of agar diffusion tests and time-kill curves confirmed the synergistic interaction, but no antagonistic action was observed.

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Yamazaki, Y., W. Hummel, and M. R. Kula. "Ein neues Verfahren zum direkten Nachweis mikrobieller Aminoacylaseaktivität auf Agarplatten mit o-Phthalaldehyd / A New Detection Procedure for Aminoacylase Activity of Microorganisms Directly on Plate Culture with o-Phthalaldehyde." Zeitschrift für Naturforschung C 42, no. 9-10 (October 1, 1987): 1082–88. http://dx.doi.org/10.1515/znc-1987-9-1013.

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Not less than 1 nmol of methionine and phenylalanine were detected as fluorescent spots on agar plates with ophthalaldehyde reagent under UV light. Microorganisms were grown on thin- agar-layer coated filter papers placed on nutrient agar plates, and then transfered onto new plates lacking nutrients by moving the papers. After the background amino compounds were removed by the diffusion to the bottom plates, the paper cultures were moved and incubated on assay plates containing N-acetylmethionine or N-acetylphenylalanine. The amino acids formed around the colonies were visualized by the ophthalaldehyde procedure to indicate aminoacylase activity of microorganisms. The substrate- and stereospecificity of the enzyme was shown for some strains on the agar plates by this procedure.

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Alshammari, Hatem, Jessica Neilands, Gunnel Svensäter, and Andreas Stavropoulos. "Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis." Antibiotics 10, no. 2 (February 3, 2021): 150. http://dx.doi.org/10.3390/antibiotics10020150.

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Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis.

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Schwarz, Patrick, Elie Djenontin, and Eric Dannaoui. "Colistin and Isavuconazole Interact Synergistically In Vitro against Aspergillus nidulans and Aspergillus niger." Microorganisms 8, no. 9 (September 21, 2020): 1447. http://dx.doi.org/10.3390/microorganisms8091447.

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The in vitro interactions of isavuconazole in combination with colistin were evaluated against 55 clinical Aspergillus species isolates belonging to the five most important species (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) responsible for human aspergillosis by a microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference method for antifungal susceptibility testing. Selected isolates (A. nidulans, n = 10; A. niger, n = 15) were additionally evaluated by an agar diffusion assay using isavuconazole gradient concentration strips with or without colistin incorporated Roswell Parc Memorial Institute (RPMI) agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index. Using the checkerboard method, combination isavuconazole–colistin was synergistic for 100% of the 15 A. nidulans isolates and for 60% of the 20 A. niger isolates. No interactions were found for any of the other isolates. By agar diffusion assay, minimal inhibitory concentrations (MICs) in combination decreased compared to isavuconazole alone for 92% of the isolates. No interactions were found for any A. nidulans isolates, but synergy was observed for 40% of the A. niger isolates. A poor essential agreement of EUCAST and gradient concentration strip MICs at ± 2 log2 dilutions with 0% was obtained. Antagonistic interactions were never observed regardless of the technique used.

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Prastiyanto, Muhammad Evy, Inas Hasna Azizah, Hafizha Dara Haqi, Bagus Dwi Yulianto, Aulia Bella Agmala, Zhafira Dias Radipasari, Nita Ayu Dwi Astuti, and Arifani Rahma Putri. "In-vitro antibacterial activity of the seed extract of three-member Artocarpus towards Methicillin-Resistant Staphylococcus aureus (MRSA)." Jurnal Teknologi Laboratorium 9, no. 2 (December 31, 2020): 128–35. http://dx.doi.org/10.29238/teknolabjournal.v9i2.237.

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Methicillin-Resistant Staphylococcus aureus (MRSA) infections have created a critical need for the development of natural antibacterials from a biological source. This research aimed to investigate the antibacterial activity of the seed extract of three-member Artocarpus (Artocarpus heterophyllus, A. champeden, and A. camansi) against MRSA which are the most prevalent causes of infections in patients. Crude seed extracts of three-member Artocarpus were evaluated for their antibacterial activity against MRSA. The antibacterial activity against MRSA of the three extracts was assayed in vitro by the agar well diffusion assay and agar microdilution method and minimum bactericidal concentration. The antibacterial activity, calculated as a zone of inhibition and MIC, MBC values. The Crude seed extracts of three-member Artocarpus showed antibacterial activity against the MRSA in the agar well diffusion assay (1.5-9 mm inhibition diameter). The MIC value of extract showed at 15.62 mg/mL and the MBC value of seed extract of A. heterophyllus at 62.5 mg/mL, A. champeden at 31.25 mg/mL, A. camansi at 250 mg/mL. All seed extracts have the potential to be developed as antibacterial agents, particularly against MRSA strain. Studies on the antibacterial activity against MRSA can provide new information about the benefits seed of members of Artocarpus as a source of natural antibacterial.

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Gummuluri, Sriram, Venkata Teja Kavalipurapu, and Apoorva Vasundhara Kaligotla. "Antimicrobial efficacy of Novel Ethanolic Extract of Morinda Citrifolia Against Enterococcus Feacalis by Agar Well Diffusion Method and Minimal Inhibitory Concentration- An Invitro Study." Brazilian Dental Science 22, no. 3 (July 30, 2019): 365–70. http://dx.doi.org/10.14295/bds.2019.v22i3.1731.

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Introduction: the long term success of root canal treatment is ultimately related to the effective debridement and disinfection of the root canal system. Hence, the irrigants play an important role in achieving the good penetrability and bactericidal activity. The present study was mainly aimed at evaluating the invitro antimicrobial efficacy of Novel Ethanolic Extract of Morinda Citrifolia by agar well diffusion and minimal inhibitory concentration. Materials and Methods:the antimicrobial efficacy of the Novel Ethanolic Extract of Morinda Citrifolia was tested using agar well diffusion and minimal inhibitory concentration was assessed. The zone of inhibitions were determined at 10 mg/ml concentration of Ethanolic Extract of Morinda Citrifolia on agar well plate and Minimal Inhibitory Concentration (MIC) against tested microorganism. Results: results obtained in the present study by both qualitative and quantitative experiments revieled that the tested Ethanolic Extract of Morinda Citrifolia possesses potential antibacterial activity against Enterococcus Feacalis when compared with standard antibiotic tetracycline. the highest zone of inhibition of 15mm was showed at 1000micrograms by agar well diffusion assay. The optimal antimicrobial activity was seen at 250micrograms for Morinda Citrifolia against Enterococcus Feacalis.Conclusion: novel Ethanolic extract of Morinda Citrifolia has shown an optimal antimicrobial activity against E.Feaclais. But still, future studies are still needed.

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Suryawanshi, H. K., and N. D. Pandya. "Screening, Identification of Alkaline Proteases Producing Fungi from Soil of Different Habitats of Amalner Tahsil [Maharashtra] and Their Applications." International Journal of Applied Sciences and Biotechnology 5, no. 3 (September 27, 2017): 397–402. http://dx.doi.org/10.3126/ijasbt.v5i3.18304.

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Fungal proteases had wide applications in textile, leather, food and Pharmaceutical industries. As proteases shows proteolytic activity they are helpful in proteinic stain removal hence also used in various commercial detergent industries. For fungal isolation soil samples were collected from different sites of Amalner tahsil. (Maharashtra) e.g. crop fields, near dairy areas, poultry farms etc. Those soil samples showing alkaline pH were selected for isolation of fungi on Potato Dextrose Agar plates. Then among 14 different isolates 2 were selected for their most proteolytic activity after screening on casein agar, skimmed milk agar and gelatine agar. For submerged fermentation, these selected isolates were inoculated in production media in shake flask. After 72 hrs, plate assay was performed by taking crude enzyme after filtration and centrifugation as well as by taking partially purified enzyme.(partial purification done by ammonium sulphate precipitation method). Protease activity assay was performed by agar well diffusion method, as well as blood clot lysis activity and blood stain removal ability of protease obtained from selected isolates was studied.Selected isolates were identified,among them Aspergillus niger gives more proteolytic activity than Trichoderma longibrachiatum. Int. J. Appl. Sci. Biotechnol. Vol 5(3): 397-402

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Domig, Konrad J., Sigrid Mayrhofer, Ulrike Zitz, Christiane Mair, Agnes Petersson, Ernst Amtmann, Helmut K. Mayer, and Wolfgang Kneifel. "Antibiotic susceptibility testing of Bifidobacterium thermophilum and Bifidobacterium pseudolongum strains: Broth microdilution vs. agar disc diffusion assay." International Journal of Food Microbiology 120, no. 1-2 (November 2007): 191–95. http://dx.doi.org/10.1016/j.ijfoodmicro.2007.07.064.

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Arikan, Sevtap, Victor Paetznick, and John H. Rex. "Comparative Evaluation of Disk Diffusion with Microdilution Assay in Susceptibility Testing of Caspofungin against Aspergillus and Fusarium Isolates." Antimicrobial Agents and Chemotherapy 46, no. 9 (September 2002): 3084–87. http://dx.doi.org/10.1128/aac.46.9.3084-3087.2002.

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ABSTRACT We compared the disk diffusion and broth microdilution methods for susceptibility testing of caspofungin against Aspergillus (n = 78) and Fusarium (n = 22) isolates. Microdilution testing followed the NCCLS M-38P guidelines but was performed in antibiotic medium 3 supplemented to 2% glucose (AM3). Disk diffusion assays were performed on AM3 agar plates with a 2-μg caspofungin disk. By both methods, caspofungin showed favorable activity against Aspergillus isolates and no activity against Fusarium isolates. In the disk-based format, intrazonal growth that was not influenced by the drug concentration gradient was consistently observed for all of the Aspergillus isolates tested.

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Alhusadi, Nesrin Atiah, Bengisu Turgutalp, Inci Deniz, Ebru Turkoz Acar, Hande Sipahi, Mine Yarim, and Enise Ece Gurdal. "Synthesis, Antimicrobial, Antioxidant and Molecular Docking Studies on Novel 6-Methoxybenzothiazole-piperazine Derivatives with Propanamide Chain." Current Topics in Medicinal Chemistry 20, no. 19 (September 14, 2020): 1733–41. http://dx.doi.org/10.2174/1568026620666200618122500.

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Background: Infectious diseases are a major threat in the developing world and the discovery of novel antimicrobial agents remains to be crucial due to acquired resistance by the microorganisms. Additionally, various diseases can be prevented with antioxidant agents as they can eliminate the harmful effects of reactive oxygen species. Objective: In this study, it was aimed to synthesize novel compounds bearing N-(6- methoxybenzothiazol-2-yl)-3-(4-substitued piperazinyl)propanamide backbone that had antimicrobial and antioxidant activities. Mechanisms of activity were aimed to be revealed by docking studies. Methods: Antimicrobial activities were tested by agar-based disc diffusion assay, and antioxidant activities were determined by CUPRAC assay. Results: In agar-based disc diffusion assay, the most active compounds were 2b and 2e against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Compounds 2e and 2j showed promising antioxidant activity in CUPRAC assay. Docking studies were performed to optimize the interactions of compounds with DNA gyrase subunit B of S. aureus. Under the light of docking studies, a new compound with potential GyrB inhibition was designed. Antioxidant activity was also supported by docking studies on superoxide dismutase 1 enzyme in which interactions with key residues were observed. Conclusion: Ten novel benzothiazole-piperazine derivatives were synthesized and their antimicrobial and antioxidant activities were evaluated. Superoxide dismutase 1 enzyme was suggested to be a possible target for the antioxidant activity of the series.

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Martins, Yugo Araújo, Reginaldo dos Santos Sousa, and Cristiani Lopes Capistrano Gonçalves de Oliveira. "Development and Validation of a Microbiological Agar Assay for Determination of Thiamphenicol in Soft Capsules." Current Pharmaceutical Analysis 16, no. 7 (August 17, 2020): 806–13. http://dx.doi.org/10.2174/1573412915666190328213828.

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Background: Thiamphenicol belongs to the amphenicol class of antibiotic and possesses a broad-spectrum antimicrobial activity. An alternative microbiological assay for quantification of thiamphenicol in pharmaceutical formulations has not yet been reported in the literature. Objective: This study aimed to develop and validate an agar diffusion method for quantification of thiamphenicol in soft capsules. Methods: The assay was based on the inhibitory effect of thiamphenicol on the following: a strain of Kocuria rhizophila ATCC 9341, used as the test microorganism, Antibiotic 1culture medium, phosphate buffer pH 6, 0, inoculum at a concentration of 1%, as well as standard and sample solutions at the concentrations of 20.0, 40.0 and 80.0 μg mL-1. Results: The method validation yielded good results for the parameters of linearity, precision, accuracy, robustness and selectivity. The experimental statistic results were analyzed using analysis of variance (ANOVA). The method was found to be linear (r2 = 0.9992) in the range of 20-80 μg mL-1, precise (inter-assay R.S.D = 0.09%), accurate (R.S.D. = 4.65%), specific, and robust. Conclusion: The results demonstrated the validity of the proposed bioassay, which allows for reliable quantification of thiamphenicol in a pharmaceutical sample. An alternative methodology for thiamphenicol determination in routine quality control has been reported herein.

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Dar, Umair Ikram, Farooq Saleem, and Saad Touqeer. "Antimicrobial and antioxidant activity of Embelia robusta: a common adulterant in black pepper." Pakistan Journal of Pharmaceutical Research 2, no. 2 (July 15, 2016): 136. http://dx.doi.org/10.22200/pjpr.20162136-141.

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The present study was aimed to investigate the phytochemistry as well as the antibacterial, antifungal, antioxidant and irritant activities of fruit of Embelia robusta. Agar-well diffusion method was used for antimicrobial study whereas for antioxidant activity three tests namely, DPPH assay, β-Carotene assay and ascorbic acid content were performed. The results from antibacterial assay showed presence of antibacterial activity in all the three plant extracts (methanol, chloroform and n-hexane). Significant antioxidant activity was also found to be present and plant extracts showed no irritant effect. Alkaloids, glycosides, phenolics, tannins and flavonoids were also detected in the plant. The study shows that the plant possesses significant medicinal value.

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Chaves, Sandra, Mário Gadanho, Rogério Tenreiro, and José Cabrita. "Assessment of Metronidazole Susceptibility in Helicobacter pylori: Statistical Validation and Error Rate Analysis of Breakpoints Determined by the Disk Diffusion Test." Journal of Clinical Microbiology 37, no. 5 (1999): 1628–31. http://dx.doi.org/10.1128/jcm.37.5.1628-1631.1999.

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Metronidazole susceptibility of 100 Helicobacter pyloristrains was assessed by determining the inhibition zone diameters by disk diffusion test and the MICs by agar dilution and PDM Epsilometer test (E test). Linear regression analysis was performed, allowing the definition of significant linear relations, and revealed correlations of disk diffusion results with both E-test and agar dilution results (r 2 = 0.88 and 0.81, respectively). No significant differences (P = 0.84) were found between MICs defined by E test and those defined by agar dilution, taken as a standard. Reproducibility comparison between E-test and disk diffusion tests showed that they are equivalent and with good precision. Two interpretative susceptibility schemes (with or without an intermediate class) were compared by an interpretative error rate analysis method. The susceptibility classification scheme that included the intermediate category was retained, and breakpoints were assessed for diffusion assay with 5-μg metronidazole disks. Strains with inhibition zone diameters less than 16 mm were defined as resistant (MIC > 8 μg/ml), those with zone diameters equal to or greater than 16 mm but less than 21 mm were considered intermediate (4 μg/ml < MIC ≤ 8 μg/ml), and those with zone diameters of 21 mm or greater were regarded as susceptible (MIC ≤ 4 μg/ml). Error rate analysis applied to this classification scheme showed occurrence frequencies of 1% for major errors and 7% for minor errors, when the results were compared to those obtained by agar dilution. No very major errors were detected, suggesting that disk diffusion might be a good alternative for determining the metronidazole sensitivity of H. pylori strains.

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Journal articles on the topic 'Agar diffusion assay'

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