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Antimicrobial Agents and Chemotherapy Mar 1977A chemically defined growth medium containing physiological concentrations of magnesium and calcium ions was utilized in a microdilution procedure for antimicrobial drug...
A chemically defined growth medium containing physiological concentrations of magnesium and calcium ions was utilized in a microdilution procedure for antimicrobial drug susceptibility testing of Pseudomonas aeruginosa. Determinations of growth end points were simplified by use of sodium citrate as a sole carbon source and bromothymol blue as a pH indicator. Growth of the test organisms was detectable by a change in the indicator color from green to blue after alkalinization of the medium due to citrate utilization. Minimal inhibitory concentrations of amikacin, carbenicillin, gentamicin, and tobramycin were determined on 100 recent clinical isolates of Pseudomonas. Parallel determinations using the microdilution procedure and a conventional tube-broth dilution technique incorporating Mueller-Hinton broth with identical magnesium and calcium content generally agreed within one twofold dilution. Modal minimal inhibitory concentrations for susceptible strains using the microdilution method were: amikacin, 6 mug/ml; carbenicillin, 50 mug/ml; gentamicin, 1.5 mug/ml; tobramycin, 1.5 mug/ml. This modified microdilution technique allowed rapid, definitive minimal inhibitory concentration determinations, using growth end points defined by a color indicator change.
Topics: Amikacin; Bromthymol Blue; Carbenicillin; Citrates; Culture Media; Gentamicins; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Tobramycin
PubMed: 404961
DOI: 10.1128/AAC.11.3.415 -
Applied and Environmental Microbiology Feb 1983A new membrane filter medium was developed for the improved recovery of injured coliforms from drinking water. The new medium, termed m-T7, consists of 5.0 g of Difco...
A new membrane filter medium was developed for the improved recovery of injured coliforms from drinking water. The new medium, termed m-T7, consists of 5.0 g of Difco Proteose Peptone no. 3, 20 g of lactose, 3.0 g of yeast extract, 0.4 ml of Tergitol 7 (25% solution), 5.0 g of polyoxyethylene ether W-1, 0.1 g of bromthymol blue, 0.1 g of bromcresol purple, and 15 g of agar per liter of distilled water. Additional selectivity may be obtained by aseptically adding 0.1 microgram of penicillin G per ml to the medium after autoclaving. In laboratory studies, m-T7 agar recovered 86 to 99% more laboratory-injured coliforms than did m-Endo agar. m-T7 agar also recovered an average of 43% more verified coliforms from 67 surface and drinking water samples than did the standard m-Endo membrane filter technique. From drinking water, m-T7 agar recovered nearly three times more coliforms than did m-Endo agar. Less than 0.5% of the colonies on m-T7 agar gave false-negative reactions, whereas greater than 70% of the typical yellow colonies from m-T7 agar produced gas in lauryl tryptose broth. Most of the verified coliforms isolated on m-T7 agar belonged to one of the four common coliform genera: Escherichia, 17.6%; Klebsiella, 21.7%; Citrobacter, 17.3%; Enterobacter, 32.2%. The results demonstrate that m-T7 agar is superior to m-Endo agar, especially for the isolation of injured coliforms from drinking water.
Topics: Citrobacter; Culture Media; Enterobacter; Enterobacteriaceae; Escherichia coli; Indicators and Reagents; Klebsiella; Lactose; Water Microbiology; Water Supply
PubMed: 6338827
DOI: 10.1128/aem.45.2.484-492.1983 -
Biochimica Et Biophysica Acta Mar 1998The effect of methemoglobin on the structure of model membranes composed of phosphatidylcholine and diphosphatidylglycerol (18 : 1, mol : mol) was studied with the help...
The effect of methemoglobin on the structure of model membranes composed of phosphatidylcholine and diphosphatidylglycerol (18 : 1, mol : mol) was studied with the help of pH-indicator dye bromothymol blue. The partition coefficients characterizing the dye binding to methemoglobin or model membranes were derived from the pKaalpha dependences on the protein or phospholipid concentration. The observed character of the dye partitioning in the lipid or lipid-protein systems is interpreted in terms of the traditional electrostatic approach and some modern theories of membrane electrostatics. It is assumed that methemoglobin affects the structural and physicochemical parameters of lipid-water interface.
Topics: Animals; Bromthymol Blue; Hemoglobins; Horses; Hydrogen-Ion Concentration; Kinetics; Lipid Bilayers; Membrane Proteins; Membranes, Artificial; Methemoglobin; Models, Chemical; Molecular Probes
PubMed: 9518571
DOI: 10.1016/s0005-2736(97)00252-6 -
Applied and Environmental Microbiology Mar 1989A selective medium (XMSM) was developed for isolation of Xanthomonas maltophilia from bulk soil and plant rhizosphere environments. The XMSM basal medium contained...
A selective medium (XMSM) was developed for isolation of Xanthomonas maltophilia from bulk soil and plant rhizosphere environments. The XMSM basal medium contained maltose, tryptone, bromthymol blue, and agar. Antibiotics added to select for X. maltophilia were cycloheximide, nystatin, cephalexin, bacitracin, penicillin G, novobiocin, neomycin sulfate, and tobramycin. A comparison was made between XMSM and 1/10-strength tryptic soy broth agar for recovery of X. maltophilia from sterile and nonsterile soil infested with known X. maltophilia isolates. A recovery rate of 97% or greater for XMSM was demonstrated. XMSM was used to isolate X. maltophilia from a variety of soil and rhizosphere environments.
Topics: Culture Media; Maltose; Soil Microbiology; Xanthomonas
PubMed: 2930173
DOI: 10.1128/aem.55.3.747-750.1989 -
The Journal of Biological Chemistry May 1975The phospholipid composition of the electron transport particles and coupling factor-depleted electron transport particles of Mycobacterium phlei are the same, but they...
The phospholipid composition of the electron transport particles and coupling factor-depleted electron transport particles of Mycobacterium phlei are the same, but they differ in contents. The accessibility of partially purified phospholipase A to these membrane phospholipids was found to be different. Treatment of membranes of Mycobacterium phlei with phospholipase A impairs the rate of oxidation as well as phosphorylation. The inhibition of phosphorylation can be reversed by washing the membranes with defatted bovine serum albumin. The reconstitution of membrane-bound coupling factor-latent ATPase activity to phospholipase A-treated depleted electron transport particles and their capacity to couple phosphorylation to oxidation of substrates remained unaffected after phospholipase A treatment. However, the pH gradient as measured by bromthymol blue was not restored after reconstitution of phospholipase A-treated depleted electron transport particles with membrane-bound coupling factor-latent ATPase. These findings show that the phosphorylation coupled to the oxidation of substrates can take place without a pronounced pH gradient in these membrane vesicles. The dye 1-anilino-8-naphthalene sulfonic acid (ANS) exhibited low levels of energized and nonenergized fluorescence in phospholipase A-treated membranes. This decrease in the level of ANS fluorescence in phospholipase A-treated membranes was found to be directly related to the amount of phospholipids cleaved. The decrease in the energy-dependent ANS response in phospholipase A-treated electron transport particles, as compared with untreated electron transport particles, was shown to be a result of a change in the apparent K-d of the dye-membrane complex, and of a decrease in the number of irreversible or slowly reversible binding sites, with no change in the relative quantum efficiency of the dye. The decrease in ANS fluorescence in phospholipase A-treated particles appears to be due to a decrease in the hydrophobicity of the membranes.
Topics: Anilino Naphthalenesulfonates; Animals; Binding Sites; Cattle; Cell Membrane; Electron Transport; Hydrogen-Ion Concentration; Kinetics; Liposomes; Mycobacterium; Mycobacterium phlei; Oxidative Phosphorylation; Oxygen Consumption; Phospholipases; Phospholipids; Protein Binding; Serum Albumin, Bovine; Snake Venoms; Time Factors
PubMed: 236299
DOI: No ID Found -
European Journal of Biochemistry Nov 19911. During aerobic cation uptake in liver mitochondria, the hydrophobic pH indicator bromothymol blue undergoes a multiphase response: phase 1 (rapid acidification),... (Comparative Study)
Comparative Study
1. During aerobic cation uptake in liver mitochondria, the hydrophobic pH indicator bromothymol blue undergoes a multiphase response: phase 1 (rapid acidification), phase 2 (slow alkalinization), phase 3 (rapid alkalinization) and phase 4 (reacidification). 2. Titrations with ruthenium red and malonate indicate that the various phases depend on the relative rates of cation uptake and proton translocation: at high rates of cation uptake, phase 1 disappears and phases 2 and 3 are transformed in a monotonic process of alkalinization. 3. The comparison of the bromothymol blue response with the arsenazo III, 2',7'-bis(carboxyethyl)-5(6)carboxyfluorescein (BCECF) and safranine responses indicates that: (a) phase 2 (slow alkalinization) corresponds to a slow rise of matrix pH and a parallel decline of membrane potential; (b) phase 3 (rapid alkalinization) corresponds to termination of proton translocation and initiation of the processes of cation efflux and proton reuptake. All the above processes reach completion during phase 4. 4. Although bromothymol blue always behaves as a membrane-bound indicator, the extent to which it reflects the matrix or the cytosolic pH is a function of the membrane-potential-determined asymmetric distribution: in parallel with the lowering of the membrane potential, the dye chromophore is shifted from the cytosolic to the matrix side membrane layer. 5. A model is discussed which describes the behaviour of bromothymol blue as pH indicator recording the changes in membrane layers facing either the matrix or the cytosolic side. The complex response of the dye during cation uptake is due to two independent processes, one of pH change and another of dye intramembrane shift. Computer simulations of the dye response, based on the conversion of a kinetic model into an electrical network and closely reproducing the experimental observations, are reported.
Topics: Anaerobiosis; Animals; Arsenazo III; Biological Transport; Bromthymol Blue; Cations, Divalent; Cell Membrane; Cytosol; Fluoresceins; Hydrogen-Ion Concentration; Indicators and Reagents; Malonates; Membrane Potentials; Mitochondria, Liver; Oxygen; Protons; Rats; Ruthenium Red; Strontium
PubMed: 1718751
DOI: 10.1111/j.1432-1033.1991.tb16352.x -
Journal of Clinical Microbiology Oct 1990The rapid identification of isolates of bile-resistant Bacteroides species has clinical and therapeutic relevance because of differences in their patterns of... (Comparative Study)
Comparative Study
The rapid identification of isolates of bile-resistant Bacteroides species has clinical and therapeutic relevance because of differences in their patterns of susceptibility and virulence. Five hundred twenty-one strains of bile-resistant Bacteroides species that were previously identified by conventional biochemical methods were reexamined to determine the minimum essential parameters necessary for correct identification. Rapid tests for bile resistance, indole production, and catalase were combined with a novel scheme for biochemical determination of saccharolytic activity on arabinose, trehalose, rhamnose, and/or xylan that included the postincubation addition of bromthymol blue for visual pH determination. Organisms were inoculated into prereduced anaerobically sterilized (PRAS) carbohydrates directly from plates, and identification was complete within 24 h of obtaining a pure culture. Ninety-three percent of bile-resistant Bacteroides species from routine clinical specimens were identified correctly by this scheme; a small number of other indole-positive strains, B. splanchnicus, B. eggerthii, and B. stercoris, were misidentified as B. uniformis.
Topics: Anaerobiosis; Bacteriological Techniques; Bacteroides; Bile; Bromthymol Blue; Evaluation Studies as Topic; Humans; Hydrogen-Ion Concentration; Indoles; Species Specificity; Sterilization
PubMed: 2229345
DOI: 10.1128/jcm.28.10.2220-2223.1990 -
Journal of Food Protection Jan 1984Enumeration of Bacillus cereus on raw sprouts of mung beans and wheat was compared in three agars: mannitol-egg yolk-polymyxin (MYP), polymyxin pyruvate-egg...
Enumeration of Bacillus cereus on raw sprouts of mung beans and wheat was compared in three agars: mannitol-egg yolk-polymyxin (MYP), polymyxin pyruvate-egg yolk-mannitol-bromthymol blue, and trypticase-soy-polymyxin blood. Ten different strains of B. cereus were used to seed the sprouts. Rates of recovery for the three media were not significantly different. However, with MYP agar, B. cereus could be differentiated more easily from other microorganisms and required fewer confirmatory tests.
PubMed: 30925637
DOI: 10.4315/0362-028X-47.1.65 -
The Journal of Physiology Mar 19761. The uptake of various substituted phenolsulphophthalein dyes by cortical slices of rabbit kidney has been studied in detail in order to obtain more information on the...
1. The uptake of various substituted phenolsulphophthalein dyes by cortical slices of rabbit kidney has been studied in detail in order to obtain more information on the secretory system for organic anions. 2. The rate of initial uptake of dyes and the accumulation after incubation for 2 hr under aerobic conditions increased in the order: phenol red (PR) greater than bromophenol blue (BPB) greater than bromocresol green (BCG) greater than bromothymol blue (BTB), while the reverse order of uptake was observed under anaerobic conditions. There was no difference between the uptake of BTB under aerobic and anaerobic conditions. 3. The accumulation of dyes under anaerobic conditions could be accounted for by binding to tissue constituents. In comparison with PR (Sheikh, 1972), the substituted dyes were found to interact extensively with the 700 G (cell membranes) and cytosol fractions of renal homogenates. 4. Low concentrations of the substituted dyes efficiently inhibited the accumulation of rho-aminohippurate (PAH). The concentration of dye resulting in 50% inhibition of PAH accumulation (KI) agreed well with concentrations estimated to sustain 50% of maximal dye transport (KM). On this basis the affinity of the dyes for the transport system increases in the order: PR less than BPB less than BCG less than BTB. 5. Probenecid, 2,4-dinitrophenol, PAH, octanoate and succinate affected to a smaller extent the uptake and binding of BPB and BCG by renal tissue than that previously shown for PR (Sheikh, 1972). No inhibitory effect of these substances on the accumulation of BTB by kidney tissue was observed. 6. The binding of PSP dyes by phospholipid vesicles (liposomes) and a representative binding protein, human serum albumin, exhibited close similarity to that of binding by renal tissue. Partition experiments involving octanol-water phases indicated that the hydrophobicity of the dyes increased in the order: PR less than BPB less than BCG less than BTB. 7. The results indicate that BTB, despite its inhibitory potency, is not transported by the organic anion system. BPB and BCG are transported to a lesser extent, and interact more strongly with the transport system than does PR. It is suggested that the substituted dyes by virtue of hydrophobic interaction with the transport system reduce the movement of the mobile part of the transport system.
Topics: Aerobiosis; Aminohippuric Acids; Anaerobiosis; Animals; Biological Transport; Bromcresol Green; Bromphenol Blue; Bromthymol Blue; Caprylates; Cell Membrane; Dinitrophenols; Female; In Vitro Techniques; Kidney Cortex; Male; Phenolphthaleins; Phenolsulfonphthalein; Probenecid; Rabbits; Succinates
PubMed: 933027
DOI: 10.1113/jphysiol.1976.sp011319 -
Journal of Clinical Microbiology Jul 1983A modified oxidation-fermentation medium was developed as a practical medium for highly sensitive and specific detection of acid production from carbohydrates by...
A modified oxidation-fermentation medium was developed as a practical medium for highly sensitive and specific detection of acid production from carbohydrates by Neisseria spp. and Branhamella catarrhalis. A total of 756 strains representing 17 Neisseria spp. and Branhamella catarrhalis were tested in this medium, in which the protein concentration was reduced relative to the carbohydrate concentration, phenol red was substituted for bromthymol blue at a low concentration, and the initial pH was adjusted to 7.2. Sugar utilization patterns were consistent with published results and with other cultural and biochemical characteristics for these species. The reactions obtained using this medium were qualitatively better and more reproducible than those obtained in cystine-Trypticase agar (BBL Microbiology Systems, Cockeysville, Md.) medium.
Topics: Acids; Carbohydrate Metabolism; Culture Media; Fermentation; Neisseria; Neisseriaceae; Oxidation-Reduction
PubMed: 6885992
DOI: 10.1128/jcm.18.1.56-62.1983