Detection of hydrogen sulfide in water samples with 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole-copper(II) complex using environmentally green microplate fluorescence assay method

2019 ◽  
Author(s):  
Mahmoud H. El-Maghrabey ◽  
Riho Watanabe ◽  
Naoya Kishikawa ◽  
Naotaka Kuroda
Keyword(s):  
Hydrogen Sulfide ◽  
Water Samples ◽  
Fluorescence Assay ◽  
Assay Method ◽  
Microplate Fluorescence Assay

Measurements of assimilable organic carbon (AOC) in high saline conditions using P17

2013 ◽  
Vol 13 (2) ◽  
pp. 265-272
Author(s):  
Eunjeong Mun ◽  
Sangyoup Lee ◽  
Inhyuk Kim ◽  
Boksoon Kwon ◽  
Heedueng Park ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Samples ◽  
High Salinity ◽  
Saline Water ◽  
Assay Method ◽  
Acetate Concentration ◽  
Cell Production ◽  
High Salinity Water ◽  
Assimilable Organic Carbon ◽  
Salinity Water

Biofouling caused by the deposition or growth of microorganisms on the membrane surface is one of the major concerns in nanofiltration (NF) and reverse osmosis (RO) processes. Assimilable organic carbon (AOC) has been a useful index to assess the growth potential of bacteria. In the case of drinking water, the AOC assay method has been widely applied to estimate growth or regrowth potential of bacteria in distribution and storage systems. However, studies on AOC measurement for high salinity water samples such as brackish water and seawater are rather scarce. The objective of this research is to investigate the influence of water salinity on the conventional AOC assay method. AOC samples with different salt concentrations were prepared by varying NaCl concentration from 0 to 35,000 mg/L, while the acetate concentration was held at 100 μg/L. The number of cells produced in water samples was measured by the heterotrophic plate count (HPC) method using R2A agar. The result showed that the cell production of Pseudomonas fluorescens strain P17 and Spirillum strain NOX decreased with increasing salinity. Especially, the growth of Spirillum strain NOX was noticeably influenced by water salinity. To further observe the relation between acetate concentration and cell production in high salinity water, organic-free saline water samples were prepared by spiking NaCl in deionized (DI) water. The organic-free saline water samples were enriched with acetate of which concentration was varied to be 0–1,000 μg/L (as acetate). Also, P. fluorescens strain P17 was adjusted to high total dissolved solids (TDS) condition prior to being injected into the saline water samples. The result demonstrated that the amount of microorganisms increased with increasing acetate concentration. Although AOC measurement of saline water using Spirillum strain NOX seemed unacceptable, it was suggested that P. fluorescens strain P17 has the possibility to be used in measuring AOC in saline water. Moreover, the yield factor was altered as a result of reflecting salinity impact as the growth number of P. fluorescens strain P17 was unstable with high saline condition.

scholarly journals Evaluation of a High-Throughput Fluorescence Assay Method for hERG Potassium Channel Inhibition

2005 ◽  
Vol 10 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Arnulf Dorn ◽  
Francis Hermann ◽  
Andreas Ebneth ◽  
Hendrick Bothmann ◽  
Gerhard Trube ◽  
...  
Keyword(s):  
Drug Development ◽  
Potassium Channel ◽  
Fluorescent Dyes ◽  
False Negative ◽  
Qt Prolongation ◽  
Fluorescence Assay ◽  
Assay Method ◽  
Cardiac Side Effects ◽  
Channel Inhibition ◽  
Wide Range

The number of projects in drug development that fail in late phases because of cardiac side effects such as QT prolongation can impede drug discovery and development of projects. The molecular target responsible for QT prolongation by a wide range of pharmaceutical agents is the myocardial hERG potassium channel. It is therefore desirable to screen for compound interactions with the hERG channel at an early stage of drug development. Here, the authors report a cell-based fluorescence assay using membrane potential-sensitive fluorescent dyes and stably transfected hERG channels from CHO cells. The assay allows semiautomated screening of compounds for hERG activity on 384-well plates and is sufficiently rapid for testing a large number of compounds. The assay is robust as indicated by a Z′ factor larger than 0.6. The throughput is in the range of 10,000 data points per day, which is significantly higher than any other method presently available for hERG. The data obtained with the fluorescence assay were in qualitative agreement with those from patch-clamp electrophysiological analysis. There were no false-positive hits, and the rate of false-negative compounds is currently 12% but might be further reduced by testing compounds at higher concentration. Quantitative differences between fluorescence and electrophysiological methods may be due to the use- or voltage-dependentactivity of the antagonists.

Development of a microplate fluorescence assay for kynurenine aminotransferase

2011 ◽  
Vol 409 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Jacky Wong ◽  
William J. Ray ◽  
Anna Y. Kornilova
Keyword(s):  
Fluorescence Assay ◽  
Kynurenine Aminotransferase ◽  
Microplate Fluorescence Assay

Applying a most probable number method for enumerating planktonic, dissimilatory, ammonium-producing, nitrate-reducing bacteria in oil field waters

2005 ◽  
Vol 51 (8) ◽  
pp. 725-729 ◽  
Author(s):  
Ruth E Eckford ◽  
Phillip M Fedorak
Keyword(s):  
Hydrogen Sulfide ◽  
Water Samples ◽  
Oil Field ◽  
Most Probable Number ◽  
Minor Role ◽  
Probable Number ◽  
A Minor ◽  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria ◽  
Oil Field Water

A most probable number (MPN) method was used to enumerate dissimilatory ammonium-producing, nitrate-reducing bacteria (DAP-NRB) in oil field waters and to determine whether they were stimulated by nitrate addition used to control hydrogen sulfide production. An ammonium production medium with 5 carbon and energy sources (acetate, glucose, glycerol, pyruvate, and succinate) and nitrate was used in a 3-tube MPN procedure to enumerate DAP-NRB. These bacteria were detected in 12 of 18 oil field water samples, but they were seldom detected in wellhead samples. Three oil field water samples were amended with nitrate in serum bottles and the numbers of different NRB were determined over a 38-day incubation time. This amendment stimulated increases in the numbers of heterotrophic NRB and autotrophic nitrate-reducing, sulfide-oxidizing bacteria, but DAP-NRB remained a minor portion of these communities. Overall, DAP-NRB were present in many of the oil field waters that were examined but their numbers were low. It appears that DAP-NRB would play a minor role in the consumption of nitrate injected into oil field waters for the control of hydrogen sulfide production.Key words: heterotroph, nitrate-reducing bacteria, dissimilatory nitrate reduction, ammonium, petroleum.

scholarly journals A smartphone microscope method for simultaneous detection of (oo)cyst of Cryptosporodium and Giardia

2020 ◽  
Author(s):  
Retina Shrestha ◽  
Rojina Duwal ◽  
Sajeev Wagle ◽  
Samiksha Pokhrel ◽  
Basant Giri ◽  
...  
Keyword(s):  
Water Samples ◽  
Simultaneous Detection ◽  
Field Of View ◽  
Assay Method ◽  
Gastrointestinal Disorders ◽  
Giardia Cyst ◽  
White Led ◽  
Major Health ◽  
Microscope Imaging ◽  
Illumination Source

AbstractGastrointestinal disorders caused by ingestion of (oo)cysts of Cryptosporodium and Giardia is one of the major health problems in developing countries. We developed a smartphone based microscopic assay method to screen (oo)cysts of Cryptosporodium and Giardia contamination in vegetable and water samples. We used sapphire ball lens as the major imaging element to modify a smartphone as a microscope. Imaging parameters such as field of view and magnification, and image contrast under different staining and illumination conditions were measured. The smartphone microscope method consisting of ball lens of 1 mm diameter, white LED as illumination source and Lugols’s iodine staining provided magnification and contrast capable of distinguishing (oo)cysts of Crypstopsporodium and Giardia in the same sample. The analytical performance of the method was tested by spike recovery experiments. The spiking recovery experiments performed on cabbage, carrot, cucumber, radish, tomatoes, and water resulted 26.8±10.3, 40.1±8.5, 44.4±7.3, 47.6±11.3, 49.2 ±10.9, and 30.2±7.9% recovery for Cryptosporodium, respectively and 10.2±4.0, 14.1±7.3, 24.2±12.1, 23.2±13.7, 17.1±13.9, and 37.6±2.4 % recovery for Giardia, respectively. These recovery results were found to be similar when compared with the commercial brightfield and fluorescence microscopes. We tested the smartphone microscope system for detecting (oo)cysts on 7 types of vegetable (n=196) and river water (n=18) samples. Forty two percent vegetable and thirty-nine percent water samples were found to be contaminated with Cryptosporodium oocyst. Similarly, thirty one percent vegetable and thirty three percent water samples were contaminated with Giardia cyst. This study showed that the developed method can be a cheaper alternative for simultaneous detection of (oo)cysts in vegetable and water samples.

DETECTION OF BACTERIOPHAGES AGAINST ESKAPE GROUP OF NOSOCOMIAL PATHOGENS FROM GANGA RIVER WATER DURING COMMUNITY BATH AT VARIOUS RITUALS: SINCE 2013–2019

2020 ◽  
pp. 17-21
Author(s):  
Raghvendra Raman Mishra ◽  
Gopal Nath
Keyword(s):  
Water Samples ◽  
Antibiotic Sensitivity ◽  
Assay Method ◽  
Clinical Samples ◽  
Bacteriophage Therapy ◽  
Acinetobacter Baumanii ◽  
E Coli ◽  
Bacterial Lawn ◽  
Phage Sensitivity ◽  
Ganga Water

Introduction: Several species of bacterial contaminants are at the high level in river Ganga water but question arises that, why Ganga water is not spoiled even left for long time and answer is a presence of biological components including bacteriophage and bioactive component such as nanoparticles. Objective: In the present study our aim was to detect bacteriophages of resistant microbes such as ESKAPE group of nosocomial and S. Typhi. from different Ganga water samples collected on different rituals. Material & Methods: This study started since 2013 and completed in 2020. As per study design water sample from different places (Prayagraj, Mirzapur and Varanasi) and sites were collected. A total 210 strains (30 each) of Enterococcus faecium (E. faecium), Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae), Acinetobacter baumanii (A. baumannii), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) ( Called as ESKAPE group) and additionally S. Typhi were identified from the in 500 clinical samples. These identified strains were processed for their biochemical test microscopy and antibiotic sensitivity for its conformation. Confirmed ESKAPE and S. Typhi strains were used for lawn culture. The bacteriophages were isolated from the collected Ganga water samples by using the double layer agar assay method. Results and Discussion: Bacteriophages were observed in the form of plaques on the bacterial lawn culture. Among 210 strains (30 each) of E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, E. coli and S. Typhi  total 52 phages were detected in the form of plaques on the bacterial lawn culture. Maximum no of phage sensitivity were identified with E. coli (13) then in S. aureus (11). Eight phages of ware specific to S. Typhi and seven were specific to P. aeruginosa and how ever in six phages are specific to K. pneumoniae and E. faecium. Minimum no of phage sensitivity were identified with A. baumanii (1). Conclusion:  Our study concludes that Ganga water is a huge source of above detected bacteriophages among all possible natural sources with full of diversity. This is development of a phage bank, which will be useful for bacteriophage therapy in near future.

Microplate fluorescence assay for the quantification of double stranded DNA using SYBR Green I dye

2006 ◽  
Vol 28 (19) ◽  
pp. 1587-1594 ◽  
Author(s):  
Johanna Leggate ◽  
Ray Allain ◽  
Leah Isaac ◽  
Burton W. Blais
Keyword(s):  
Sybr Green ◽  
Fluorescence Assay ◽  
Sybr Green I ◽  
Double Stranded Dna ◽  
Microplate Fluorescence Assay

scholarly journals Optimization of a Microplate Assay for Generating Listeria Monocytogenes, E. Coli O157:H7, and Salmonella Biofilms and Enzymatic Recovery for Enumeration

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 541 ◽  
Author(s):  
Manish Aryal ◽  
Preetty Pranatharthiharan ◽  
Peter M. Muriana
Keyword(s):  
Foodborne Pathogens ◽  
Food Processing ◽  
Hydrolytic Enzymes ◽  
Fluorescence Assay ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Planktonic Cells ◽  
E Coli ◽  
Adherence Data ◽  
Microplate Fluorescence Assay

Biofilms enable the persistence of pathogens in food processing environments. Sanitizing agents are needed that are effective against pathogens entrapped in biofilms that are more difficult to inactivate than planktonic cells that are displaced and found on equipment surfaces. We examined conditions to develop, analyze, and enumerate the enhanced biofilms of three different foodborne pathogens assisted by fluorescence adherence assay and enzymatic detachment. We compared three different isomeric forms of fluorescent substrates that are readily taken up by bacterial cells based on carboxy-fluorescein diacetate (5-CFDA, 5,6-CFDA, 5,6-CFDA, SE). Biofilm-forming strains of Escherichia coli O157:H7 F4546 and Salmonella Montevideo FSIS 051 were identified using a microplate fluorescence assay defined previously for L. monocytogenes. Adherence levels were determined by differences in relative fluorescence units (RFU) as well as recovered bacterial cells. Multiple hydrolytic enzymes were examined for each representative pathogen for the most suitable enzyme for detachment and enumeration to confirm adherence data obtained by fluorescence assay. Cultures were grown overnight in microplates, incubated, washed and replenished with fresh sterile growth medium; this cycle was repeated for seven consecutive days to enrich for robust biofilms. Treatments were performed in triplicate and compared by one-way analysis of variance (ANOVA) to determine significant differences (p < 0.05).

A microplate fluorescence assay for DAPA aminotransferase by detection of the vicinal diamine 7,8-diaminopelargonic acid

2013 ◽  
Vol 432 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Stéphane Mann ◽  
Luc Eveleigh ◽  
Olivier Lequin ◽  
Olivier Ploux
Keyword(s):  
Fluorescence Assay ◽  
Microplate Fluorescence Assay
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