scholarly journals Coupling Microplate-Based Antibacterial Assay with Liquid Chromatography for High-Resolution Growth Inhibition Profiling of Crude Extracts: Validation and Proof-of-Concept Study with Staphylococcus aureus

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1550
Author(s):  
Hamidreza Ardalani ◽  
Syariful Anam ◽  
Kresten J.K. Kromphardt ◽  
Dan Staerk ◽  
Kenneth T. Kongstad
Keyword(s):  
Staphylococcus Aureus ◽  
High Resolution ◽  
Growth Inhibition ◽  
Pathogenic Bacteria ◽  
Fermentation Broth ◽  
Bioactive Constituents ◽  
Crude Extracts ◽  
Ic50 Values ◽  
Alternaria Sp ◽  
Development And Validation

With the identification of novel antibiotics from nature being pivotal in the fight against human pathogenic bacteria, there is an urgent need for effective methodologies for expedited screening of crude extracts. Here we report the development and validation of a simple and dye-free antimicrobial assay in 96-well microplate format, for both determination of IC50 values and high-resolution inhibition profiling to allow pin-pointing of bioactive constituents directly from crude extracts. While commonly used antimicrobial assays visualize cell viability using dyes, the developed and validated assay conveniently uses OD600 measurements directly on the fermentation broth. The assay was validated with an investigation of the inhibitory activity of DMSO against Staphylococcus aureus, temperature robustness, interference by coloured crude extracts as well as inter-day reproducibility. The potential for high-resolution S. aureus growth inhibition profiling was evaluated on a crude extract of an inactive Alternaria sp., spiked with ciprofloxacin.

scholarly journals Taxonomic Characterization and Secondary Metabolite Analysis of NEAU-wh3-1: An Embleya Strain with Antitumor and Antibacterial Activity

2020 ◽  
Vol 8 (3) ◽  
pp. 441 ◽  
Author(s):  
Han Wang ◽  
Tianyu Sun ◽  
Wenshuai Song ◽  
Xiaowei Guo ◽  
Peng Cao ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Fermentation Broth ◽  
Sequence Similarity ◽  
Tumor Cell Line ◽  
Triticum Aestivum L ◽  
New Drugs ◽  
Rrna Gene ◽  
Physiological Characterization ◽  
Ic50 Values

Cancer is a serious threat to human health. With the increasing resistance to known drugs, it is still urgent to find new drugs or pro-drugs with anti-tumor effects. Natural products produced by microorganisms have played an important role in the history of drug discovery, particularly in the anticancer and anti-infective areas. The plant rhizosphere ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science, especially Streptomyces. We screened Streptomyces-like strains from the rhizosphere soil of wheat (Triticum aestivum L.) in Hebei province, China, and thirty-nine strains were obtained. Among them, the extracts of 14 isolates inhibited the growth of colon tumor cell line HCT-116. Strain NEAU-wh-3-1 exhibited better inhibitory activity, and its active ingredients were further studied. Then, 16S rRNA gene sequence similarity studies showed that strain NEAU-wh3-1 with high sequence similarities to Embleya scabrispora DSM 41855T (99.65%), Embleya hyalina MB891-A1T (99.45%), and Streptomyces lasii 5H-CA11T (98.62%). Moreover, multilocus sequence analysis based on the five other house-keeping genes (atpD, gyrB, rpoB, recA, and trpB) and polyphasic taxonomic approach comprising chemotaxonomic, phylogenetic, morphological, and physiological characterization indicated that the isolate should be assigned to the genus Embleya and was different from its closely related strains, therefore, it is proposed that strain NEAU-wh3-1 may be classified as representatives of a novel species of the genus Embleya. Furthermore, active substances in the fermentation broth of strain NEAU-wh-3-1 were isolated by bioassay-guided analysis and identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. Consequently, one new Zincophorin analogue together with seven known compounds was detected. The new compound showed highest antitumor activity against three human cell lines with the 50% inhibition (IC50) values of 8.8–11.6 μg/mL and good antibacterial activity against four pathogenic bacteria, the other known compounds also exhibit certain biological activity.

scholarly journals Screening And Quantification Of Anti-Quorum Sensing And Antibiofilm Activities Of Phyllosphere Bacteria Against Biofilm Forming Bacteria

2019 ◽  
Author(s):  
NADINE AMABEL THEODORA ◽  
VANIA DOMINIKA ◽  
Diana Elizabeth Waturangi
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Salmonella Typhimurium ◽  
Enterococcus Faecalis ◽  
Crude Extract ◽  
Pathogenic Bacteria ◽  
Antibiofilm Activity ◽  
Crude Extracts ◽  
Phyllosphere Bacteria

Abstract Objective The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria ( Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa). Results We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria.

scholarly journals PERBEDAAN ZONA HAMBAT PERTUMBUHAN Staphylococcus aureus PADA BERBAGAI KONSENTRASI EKSTRAK ETANOL DAUN BIDURI SECARA IN VITRO

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Nyoman Mastra
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Inhibition ◽  
Pathogenic Bacteria ◽  
Ethanol Extract ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Growth Inhibition Zone ◽  
The Difference

ABSTRACTBackground Staphylococcus aureus is a pathogenic bacteria that can cause infection. Biduri leaf has antibacterial compound such as tannin, flavonoid, saponin, and polyphenol.Objective This study aimed to know the difference of growth inhibition zone of Staphylococcus aureus at the various concentration of ethanol extract of biduri leaf and to determine an effective concentration.Methods This study was the true experiment with posttest only control design, used Kirby-Bauer disk diffusion method with five concentrations (20%, 40%, 60%, 80%,100%), positive control (chloramphenicol 30 µg) and negative control (ethanol 96%).Result The result of this study showed the average of inhibition zone diameter of each concentration consecutively 26,2 mm, 28,3 mm, 29,7 mm, 31 mm and 31,5 mm. One Way Anova statistic analysis showed that the value of p is 0.000 so there is the difference of growth inhibition zone of Staphylococcus aureus at various concentrations of ethanol extract of a biduri leaf.Conclusion The conclusion of this study is there are differences in growth inhibition zone of Staphylococcus aureus at various concentrations of ethanol extract of biduri leaf and an effective concentration that can inhibit of Staphylococcus aureus is concentration 20% with mean inhibition zone is 26,2 mm. Keywords: ethanol extract of biduri leaf; Staphylococcus aureus; inhibition zone

scholarly journals Evaluation of antibacterial and antioxidant activities of three types of benzoin resin

2018 ◽  
Vol 9 (4) ◽  
pp. 408-411
Author(s):  
Zineb Hacini ◽  
Fatima Khedja ◽  
Ibrahim Habib ◽  
Zaouia Kendour ◽  
Zineb Debba
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antioxidant Activity ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Antioxidant Activities ◽  
Ic50 Values ◽  
Therapeutic Properties ◽  
Resin Extract ◽  
And Staphylococcus Aureus

The benzoin resin is used extensively in traditional medicine for its many reported therapeutic properties. The essential oils of three different types of benzoin resin were extracted using the traditional method in this study. The yield of essential oils of the white, red and gray types of resin was 1.01, 0.92 and 0.54%, respectively. The obtained extracts were tested against two types of pathogenic bacteria, Staphylococcus aureus and Escherichia coli. The tests showed that essential oil of gray type resin is effective against both Escherichia coli (14 mm) and Staphylococcus aureus (11 mm). The antioxidant activity has been also evaluated to compare the efficiency of different type of resin with DPPH· assay. In the DPPH· system, the antioxidant activity of the red resin extract (0.01 μg/mL) was superior to that of the white (27.32 μg/mL) and gray (42.90 μg/mL) extracts, with IC50 values, respectively.

scholarly journals In Vitro Effect of Plant Parts Extract of Senecio glaucus L. on Pathogenic Bacteria

2021 ◽  
Vol 12 (3) ◽  
pp. 3800-3810
Keyword(s):  
Chemical Composition ◽  
Pathogenic Bacteria ◽  
Antioxidant Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Bioactive Constituents ◽  
Two Samples ◽  
Ic50 Values ◽  
Vitro Effect

Senecio glaucus L. is an annual herb that grows in several Egyptian desert habitats. The diversity of habitats inhabited by this species, as well as its distribution, chemical composition, and biological activity, are all unknown. This research aimed to examine the chemical composition of S. glaucus from various environments in Egypt, as well as the antioxidant and antimicrobial activities. The general assessment of the analytical results for different parts of S. glaucus showed that the capitula and leaves in both inland and coastal samples were rich in bioactive constituents than the other parts as following (capitula > leaf > root > stem). Based on the results of IC50, the antioxidant properties of the eight parts of two samples follows the sequence capitula ˃ root ˃ leaf ˃ stem for the coastal sample, and capitula ˃ leaf ˃ stem ˃ root for the inland sample. The IC50 values ranged from 25.94 to 41.20 mg/ml in coastal sample, where the IC50 values ranged from 28.02 to 42.83 mg/ml in desert sample, compared to ascorbic acid (IC50 = 13.30 mg/ml). The antimicrobial potential of MeOH extracts of S. glaucus parts collected from different habitats exhibited different inhibitory spectrum behavior with varying degrees of inhibition against six Gram-positive bacteria and four Gram-negative bacteria. In both coastal and inland samples, the E. coli inhibition zone was the most susceptible bacterium. Whereas, in the case of the coastal sample, the inhibition zone of B. subtilis was the most sensitive bacterium. The results of the antibacterial test were compared with 3 standard antibiotics.

Extraction and Antifungal Activity of a Lipopeptide Biosurfactant

2014 ◽  
Vol 936 ◽  
pp. 669-673
Author(s):  
Fan Ren Fang ◽  
Sheng Zhong ◽  
Yan Dong ◽  
Li Jing Gong
Keyword(s):  
Staphylococcus Aureus ◽  
Surface Tension ◽  
Pseudomonas Aeruginosa ◽  
Antifungal Activity ◽  
Pathogenic Bacteria ◽  
Fermentation Broth ◽  
Pathogenic Fungi ◽  
Antibiotic Activity ◽  
Lipopeptide Biosurfactant ◽  
Antibacterial Spectrum

A kind of biosurfactant produced by ascendant strain BS01 was screened by detecting the surface tension , diameter of oil spreading. The structure of the biosurfactant extracted from fermentation broth of strain BS01 was verified by IR and UV .It has superior surfactive properties. Its critical micelle concentration (CMC) is 25mg/l and the surface tension is 29.6mN/m in CMC. The biosurfactant shows excellent antibacterial spectrum against agricultural pathogenic fungi and human pathogenic bacteria. Especially, it presents good antibiotic activity against Sclerotinia sclerotiorum ,staphylococcus aureus Rosenbach and pseudomonas aeruginosa .

scholarly journals Inhibition of MurA Enzyme from Escherichia coli and Staphylococcus aureus by Diterpenes from Lepechinia meyenii and Their Synthetic Analogs

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1535
Author(s):  
Macarena Funes Chabán ◽  
Martina Hrast ◽  
Rok Frlan ◽  
Dafni G. Graikioti ◽  
Constantinos M. Athanassopoulos ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Plant Origin ◽  
Synthetic Analogs ◽  
E Coli ◽  
Ic50 Values ◽  
Resistant Strains ◽  
Hydroxy Groups ◽  
And Staphylococcus Aureus

Enzymes MurA and MurF, involved in bacterial cell wall synthesis, have been validated as targets for the discovery of novel antibiotics. A panel of plant-origin antibacterial diterpenes and synthetic analogs derived therefrom were investigated for their inhibitory properties on these enzymes from Escherichia coli and Staphylococcus aureus. Six compounds were proven to be effective for inhibiting MurA from both bacteria, with IC50 values ranging from 1.1 to 25.1 µM. To further mechanistically investigate the nature of binding and to explain the activity, these compounds were docked into the active site of MurA from E. coli. The aromatic ring of the active compounds showed a T-shaped π–π interaction with the phenyl ring of Phe328, and at least one hydrogen bond was formed between the hydroxy groups and Arg120 and/or Arg91. The results disclosed here establish new chemical scaffolds for the development of novel entities targeting MurA as potential antibiotics to combat the threat of pathogenic bacteria, particularly resistant strains.

scholarly journals Screening and quantification of anti-quorum sensing and antibiofilm activities of phyllosphere bacteria against biofilm forming bacteria

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Nadine Amabel Theodora ◽  
Vania Dominika ◽  
Diana Elizabeth Waturangi
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Crude Extract ◽  
Pathogenic Bacteria ◽  
Antibiofilm Activity ◽  
Biofilm Inhibition ◽  
Crude Extracts ◽  
Turbid Zone ◽  
Phyllosphere Bacteria

Abstract Objective The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria (Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa). Results We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extract showed the largest turbid zone (1,27 cm) using isolate JB 14B with concentration of 10 mg/mL and the narrowest turbid zone isolate (1 cm) using JB 18B with concentration of 10 mg/mL. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria, it showed the highest biofilm inhibition (90%) and destruction activities (76%) against S. aureus.

scholarly journals Screening And Quantification Of Anti-Quorum Sensing And Antibiofilm Activities Of Phyllosphere Bacteria Against Biofilm Forming Bacteria

2019 ◽  
Author(s):  
NADINE AMABEL THEODORA ◽  
VANIA DOMINIKA ◽  
Diana Elizabeth Waturangi
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Salmonella Typhimurium ◽  
Enterococcus Faecalis ◽  
Crude Extract ◽  
Pathogenic Bacteria ◽  
Antibiofilm Activity ◽  
Crude Extracts ◽  
Phyllosphere Bacteria

Abstract Objective The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria ( Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa). Results We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria.

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