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Journal of Clinical Microbiology Nov 1988Bromthymol blue, at a concentration of 0.1% in tryptose-glucose broth, inhibited growth of 98.4% of Escherichia coli serotype O157:H7 isolates but only 0.8% of E. coli...
Bromthymol blue, at a concentration of 0.1% in tryptose-glucose broth, inhibited growth of 98.4% of Escherichia coli serotype O157:H7 isolates but only 0.8% of E. coli non-O157:H7 isolates after an overnight incubation at 44.5 degrees C, but not 35 degrees C. The inhibition was dependent on temperature, density of inoculum, bromthymol blue concentration, time of incubation, and composition of the medium. Compared with serologic typing, the inhibition had sensitivity, specificity, predictive values of the positive and negative tests, and overall agreement between the two tests of 98.4, 99.2, 98.4, 99.2, and 98.9%, respectively. The inhibition could be useful as a presumptive test to identify E. coli isolates of serotype O157:H7, especially in laboratories that do not have serotyping capabilities.
Topics: Bromthymol Blue; Escherichia coli; Humans; Serotyping; Thymol
PubMed: 3069858
DOI: 10.1128/jcm.26.11.2248-2249.1988 -
A Convenient, Rapid, Sensitive, and Reliable Spectrophotometric Assay for Adenylate Kinase Activity.Molecules (Basel, Switzerland) Feb 2019Enzymatic activity assays are essential and critical for the study of enzyme kinetics. Adenylate kinase (Adk) plays a fundamental role in cellular energy and nucleotide...
Enzymatic activity assays are essential and critical for the study of enzyme kinetics. Adenylate kinase (Adk) plays a fundamental role in cellular energy and nucleotide homeostasis. To date, assays based on different principles have been used for the determination of Adk activity. Here, we show a spectrophotometric analysis technique to determine Adk activity with bromothymol blue as a pH indicator. We analyzed the effects of substrates and the pH indicator on the assay using orthogonal design and then established the most optimal assay for Adk activity. Subsequently, we evaluated the thermostability of Adk and the inhibitory effect of KCl on Adk activity with this assay. Our results show that this assay is simple, rapid, and precise. It shows great potential as an alternative to the conventional Adk activity assay. Our results also suggest that orthogonal design is an effective approach, which is very suitable for the optimization of complex enzyme reaction conditions.
Topics: Adenylate Kinase; Bromthymol Blue; Homeostasis; Hydrogen-Ion Concentration; Kinetics; Phosphorylation; Potassium Chloride; Spectrophotometry
PubMed: 30781833
DOI: 10.3390/molecules24040663 -
PloS One 2015Over the last few decades the establishment of nanoparticles as suitable drug carriers with the transport of drugs across biological barriers such as the...
Over the last few decades the establishment of nanoparticles as suitable drug carriers with the transport of drugs across biological barriers such as the gastrointestinal barrier moved into the focus of many research groups. Besides drug transport such carrier systems are well suited for the protection of drugs against enzymatic and chemical degradation. The preparation of biocompatible and biodegradable nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) is intensively described in literature, while especially nanoparticles with cationic properties show a promising increased cellular uptake. This is due to the electrostatic interaction between the cationic surface and the negatively charged lipid membrane of the cells. Even though several studies achieved the successful preparation of nanoparticles stabilized with the cationic surfactants such as didodecyldimethylammonium bromide (DMAB), in most cases insufficient attention was paid to a precise analytical characterization of the nanoparticle system. The aim of the present work was to overcome this deficit by presenting a new perspective in the formulation and characterization of DMAB-stabilized PLGA nanoparticles. Therefore these nanoparticles were carefully examined with regard to particle diameter, zeta potential, the effect of variation in stabilizer concentration, residual DMAB content, and electrolyte stability. Without any steric stabilization, the DMAB-modified nanoparticles were sensitive to typical electrolyte concentrations of biological environments due to compression of the electrical double layer in conjunction with a decrease in zeta potential. To handle this problem, the present study proposed two modifications to enable electrolyte stability. Both polyvinyl alcohol (PVA) and polyethylene glycol (PEG) modified DMAB-PLGA-nanoparticles were stable during electrolyte addition. Furthermore, in contrast to unmodified DMAB-PLGA-nanoparticles and free DMAB, such modifications led to a lower cytotoxic activity against Caco-2 cells. In conclusion this study offers a closer and critical point of view on preparation, in vitro and analytical evaluation of DMAB-stabilized PLGA nanoparticles for the physiological use.
Topics: Bromthymol Blue; Caco-2 Cells; Colloids; Electrolytes; Humans; Lactic Acid; Microscopy, Fluorescence; Nanoparticles; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Quaternary Ammonium Compounds
PubMed: 26147338
DOI: 10.1371/journal.pone.0127532 -
Journal of Clinical Pathology Oct 1976Amniotic fluid lecithin and sphingomyelin areas after extraction and chromatography are rendered permanently visible by the use of bromthymol blue dye buffered to a pH...
Amniotic fluid lecithin and sphingomyelin areas after extraction and chromatography are rendered permanently visible by the use of bromthymol blue dye buffered to a pH of 11-3.
Topics: Amniotic Fluid; Bromthymol Blue; Chromatography, Thin Layer; Female; Humans; Methods; Phosphatidylcholines; Pregnancy; Sphingomyelins
PubMed: 977767
DOI: 10.1136/jcp.29.10.908 -
Annals of Laboratory Medicine Sep 2016Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk...
BACKGROUND
Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT).
METHODS
Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases.
RESULTS
The paper disks were simple to prepare, and the dried disks were stable at -20°C and at 4°C. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB.
CONCLUSIONS
The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Bromthymol Blue; Drug Resistance, Bacterial; Gram-Negative Bacteria; Imipenem; Microbial Sensitivity Tests; Paper; beta-Lactamases
PubMed: 27374708
DOI: 10.3343/alm.2016.36.5.434 -
Journal of Clinical Microbiology Nov 2009Cryptococcus neoformans and Cryptococcus gattii are closely related pathogenic fungi. Cryptococcus neoformans is ecologically widespread and affects primarily...
Cryptococcus neoformans and Cryptococcus gattii are closely related pathogenic fungi. Cryptococcus neoformans is ecologically widespread and affects primarily immunocompromised patients, while C. gattii is traditionally found in tropical climates and has been reported to cause disease in immunocompetent patients. l-Canavanine glycine bromothymol blue (CGB) agar can be used to differentiate C. neoformans and C. gattii, but there are few reports of its performance in routine clinical practice. Growth of C. gattii on CGB agar produces a blue color, indicating the assimilation of glycine, while C. neoformans fails to cause a color change. Using reference and clinical strains, we evaluated the ability of CGB agar and D2 large ribosomal subunit DNA sequencing (D2 LSU) to differentiate C. neoformans and C. gattii. One hundred two yeast isolates were screened for urease activity, melanin production, and glycine assimilation on CGB agar as well as by D2 sequencing. Seventeen of 17 (100%) C. gattii isolates were CGB positive, and 54 of 54 C. neoformans isolates were CGB negative. Several yeast isolates other than the C. gattii isolates were CGB agar positive, indicating that CGB agar cannot be used alone for identification of C. gattii. D2 correctly identified and differentiated all C. gattii and C. neoformans isolates. This study demonstrates that the use of CGB agar, in conjunction with urea hydrolysis and Niger seed agar, or D2 LSU sequencing can be reliably used in the clinical laboratory to distinguish C. gattii from C. neoformans. We describe how CGB agar and D2 sequencing have been incorporated into the yeast identification algorithm in our laboratory.
Topics: Algorithms; Bromthymol Blue; Canavanine; Clinical Laboratory Techniques; Cryptococcosis; Cryptococcus gattii; Cryptococcus neoformans; Culture Media; DNA, Fungal; DNA, Ribosomal; Diagnosis, Differential; Fungal Proteins; Glycine; Humans; Melanins; RNA, Ribosomal, 28S; Sequence Analysis, DNA; Urease
PubMed: 19794048
DOI: 10.1128/JCM.01072-09 -
Acta Poloniae Pharmaceutica 2015Two simple, rapid and sensitive spectrophotometric methods have been developed for the determination of naproxen in pure, pharmaceutical preparation and human serum...
Two simple, rapid and sensitive spectrophotometric methods have been developed for the determination of naproxen in pure, pharmaceutical preparation and human serum samples. These methods are based on the formation of yellow ion-pair complexes between naproxen and two sulfophthalein acid dyes, namely bromocresol green (BCG method) and bromothymol blue (BTB method). The resulting complexes were measured at 424 nm (BCG method) and at 422 nm (BTB method). The effects of variables such as reagent concentration and reaction time were investigated to optimize the procedure. Beer's law was obeyed in the concentration range of 10-105 µg/mL and 5-85 µg/mL and the detection limits were found to be 0.347 and 0.31 µg/mL for BCG and BTB methods, respectively. The developed methods have been successfully applied for the determination of naproxen in bulk drugs, pharmaceutical formulations and human serum samples with good accuracy and precision. The results are comparable to those of reference methods, and hence are recommended for quality control and routine analysis.
Topics: Bromcresol Green; Bromthymol Blue; Humans; Hydrogen-Ion Concentration; Naproxen; Spectrophotometry; Tablets
PubMed: 26665392
DOI: No ID Found -
The Journal of Physiology Jul 19691. An enzyme which can be extracted from brain inactivates nerveside in the optimum pH range 5.8-7.0.2. The polybasic acids trypan blue and its analogue trypan red,...
1. An enzyme which can be extracted from brain inactivates nerveside in the optimum pH range 5.8-7.0.2. The polybasic acids trypan blue and its analogue trypan red, bromphenol blue and its analogue bromthymol blue at concentrations of 0.22 mM and ethylenediaminetetra-acetic acid (EDTA) at a concentration of 1 mM are strong inhibitors of the enzyme.3. Penicillin which is a monobasic carboxylic acid also inhibits the enzyme but only if concentrations as high as 3.6 mM are used. The antibiotic streptomycin which is a basic substance does not inhibit the enzyme.4. Caffeine at a concentration of 7.2 mM only weakly inhibits the enzyme.5. Chymotrypsin and wheat germ acid phosphatase also inactivate nerveside at pH 5.9 and are inhibited by the acidic dyes and penicillin. EDTA inhibits wheat germ phosphatase but activates chymotrypsin.6. Inactivation of nerveside by the brain enzyme and by wheat germ phosphatase is different from the action of chymotrypsin. Nerveside solutions incubated with chymotrypsin completely lose all biological activity whereas if incubation is carried out with either the brain enzyme or wheat germ acid phosphatase a residual biological activity remains even when the concentration of these two enzymes is increased. This residual biological activity is due to a peptide as it is destroyed by chymotrypsin.7. The manner in which nerveside is inactivated by the brain enzyme is uncertain as the preparation of the latter contained phosphodiesterase and protease activities which were similarly inhibited by the acid dyes, penicillin and EDTA.8. Pentylenetetrazole, picrotoxin, strychnine and tetanus toxin do not inhibit the brain enzyme.9. The nerveside-inactivating enzyme is not identical with the Substance P-inactivating enzyme in brain as the former is inhibited by EDTA while the latter is not.
Topics: Acid Phosphatase; Animals; Caffeine; Central Nervous System Stimulants; Cerebral Cortex; Chymotrypsin; Dogs; Edetic Acid; Enzyme Inhibitors; Hydrogen-Ion Concentration; Penicillins; Peptides; Sheep; Trypan Blue
PubMed: 4390385
DOI: 10.1113/jphysiol.1969.sp008851 -
Chemical & Pharmaceutical Bulletin Jul 2006Two simple, rapid and sensitive extractive spectrophotometric methods have been developed for the assay of trazodone hydrochloride (TRH) in pure and pharmaceutical...
Two simple, rapid and sensitive extractive spectrophotometric methods have been developed for the assay of trazodone hydrochloride (TRH) in pure and pharmaceutical formulations. These methods are based on the formation of chloroform soluble ion-association complexes of TRH with bromothymol blue (BTB) and with bromocresol purple (BCP) in KCl-HCl buffer of pH 2.0 (for BTB) and in NaOAc-AcOH buffer of pH of 3.6 (for BCP) with absorption maximum at 423 nm and at 408 nm for BTB and BCP, respectively. Reaction conditions were optimized to obtain the maximum color intensity. The absorbance was found to increase linearly with increase in concentration of TRH, which was corroborated by the calculated correlation coefficient values (0.9996, 0.9945). The systems obeyed Beer's law in the range of 0.2-14.5 and 0.2-14.1 microg/ml for BTB and BCP, respectively. Various analytical parameters have been evaluated and the results have been validated by statistical data. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, accurate and suitable for quality control applications.
Topics: Antidepressive Agents, Second-Generation; Bromcresol Purple; Bromthymol Blue; Indicators and Reagents; Molecular Structure; Pharmaceutical Preparations; Solubility; Spectrophotometry; Trazodone
PubMed: 16819213
DOI: 10.1248/cpb.54.968 -
European Journal of Biochemistry Jan 1969
Topics: Bromine; Chemical Phenomena; Chemistry; Chlorides; Dinitrophenols; Halogens; Hydrogen-Ion Concentration; Ions; Metals; Mitochondria, Muscle; Osmolar Concentration; Phenolphthaleins; Protein Binding; Radioisotopes; Spectrophotometry
PubMed: 5765737
DOI: 10.1111/j.1432-1033.1969.tb19602.x