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Revista Do Instituto de Medicina... Sep 2016Cryptococcosis is a leading invasive fungal infection in immunocompromised patients. Considering the high prevalence and severity of these infections in...
ANTIFUNGAL SUSCEPTIBILITY TESTING AND GENOTYPING CHARACTERIZATION OF Cryptococcus neoformans AND gattii ISOLATES FROM HIV-INFECTED PATIENTS OF RIBEIRÃO PRETO, SÃO PAULO, BRAZIL.
Cryptococcosis is a leading invasive fungal infection in immunocompromised patients. Considering the high prevalence and severity of these infections in immunocompromised patients attended at HC-FMRP-USP, the present research aimed to characterize the clinical isolates of Cryptococcus strains by biochemical and molecular methods and evaluate antifungal susceptibility of clinical isolates. Fifty isolates from 32 HIV-positive patients were obtained at HC-FMRP-USP. Most of the isolates (78.1%) were identified as C. neoformans, and 100% of C. neoformans and C. gattii strains were susceptible to amphotericin B, ketoconazole and fluconazole. All isolates were classified as serotype A (grubbii variety) by PCR and most of them were characterized in mating type MATa. PCR analysis of specific M13 microsatellite sequence revealed that VNI type was predominant among C. neoformans, while VGII was predominant among C. gattii. The strains did not show a significant resistance to the antifungals tested, and Canavanine-Glycine-Bromthymol Blue Agar (CGB) proved to be a reliable test presenting a good correlation with the molecular characterization. C. neoformans isolated from disseminated infections in the same patient showed molecular identity when different anatomical sites were compared; besides, the studied strains did not present a significant increase in resistance to antifungal agents. In addition, the homogeneity of the molecular types and detection of the mating types suggested a low possibility of crossing among the strains.
PubMed: 27680174
DOI: 10.1590/S1678-9946201658069 -
Journal of Agricultural and Food... Nov 2020The rationale behind the material and dye selection and the investigation of the properties of a solid-phase sensor array designed for following chicken meat spoilage is...
The rationale behind the material and dye selection and the investigation of the properties of a solid-phase sensor array designed for following chicken meat spoilage is presented, having in mind that the final target must be the naked eye identification of the degradation steps. The device is obtained by fixing five acid-base indicators, -cresol purple (1), -cresol red (2), bromothymol blue (3), thymol blue (4), and chlorophenol red (5), and a sensing molecule specific for thiols, 5,5'-dithiobis(2-nitrodibenzoic acid), called Ellman's reagent, (6) on a commercial cellulose-based support. The dimensions of the sensor and the amount of dye sorbed on the solid are carefully studied. The preparation protocol to get reproducible sensing materials is established, based on the kinetic study and the color change investigation. The material stability and the capacity of changing color, according to the acid-base properties of the dyes, are tested. The sources of uncertainty, coming from the technique employed for signal data acquisition and treatment and from the intrinsic variability of the spots based on the commercial support, are established. The highest variability does not come from photo acquisition by a mobile phone, the effect of the illumination equipment, the partial least-squares (PLS) model employed to assess the amount of dye sorbed into the solid but from the variability of different spots and was found equal to 10%. The uncertainty is adequate for final employment since it is referred to as replicates under different conditions that are definitively judged almost always identical by naked eye evaluation, which is our last target for assessing a change of the colors associated with spoilage.
Topics: Animals; Bromthymol Blue; Chickens; Color; Coloring Agents; Food Analysis; Meat; Phenolsulfonphthalein; Thymolphthalein
PubMed: 33125233
DOI: 10.1021/acs.jafc.0c03768 -
Journal of Food Protection Nov 1984An existing Bacillus cereus isolation medium (PEMBA composed of polymyxin, pyruvate, egg yolk, mannitol, bromthymol blue and agar) has been modified and its comparative...
An existing Bacillus cereus isolation medium (PEMBA composed of polymyxin, pyruvate, egg yolk, mannitol, bromthymol blue and agar) has been modified and its comparative performance evaluated. Bromthymol blue was replaced with bromcresol purple, hence the new medium was designated PEMPA. The advantage of this modification was decreased incubation time (from 48 h to 22 h) and an increased ability to recognize presumptive isolates. Recoveries of 20 reference strains of B. cereus inoculated into rice and tested on three selective media (PEMPA, PEMBA and MYP composed of mannitol, egg yolk and polymyxin) compared favorably. Additionally, quantitation of B. cereus from 23 naturally contaminated foods on MYP, PEMBA and PEMPA, and from 39 naturally contaminated foods on PEMBA and PEMPA gave comparable results.
PubMed: 30934435
DOI: 10.4315/0362-028X-47.11.856 -
Sensors (Basel, Switzerland) Feb 2019The spread of antimicrobial resistance calls for chronic wound management devices that can engage with the wound exudate and signal infection by prompt visual effects....
The spread of antimicrobial resistance calls for chronic wound management devices that can engage with the wound exudate and signal infection by prompt visual effects. Here, the manufacture of a two-layer fibrous device with independently-controlled exudate management capability and visual infection responsivity was investigated by sequential free surface electrospinning of poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA) and poly(acrylic acid) (PAA). By selecting wound pH as infection indicator, PMMA-co-MAA fibres were encapsulated with halochromic bromothymol blue (BTB) to trigger colour changes at infection-induced alkaline pH. Likewise, the exudate management capability was integrated via the synthesis of a thermally-crosslinked network in electrospun PAA layer. PMMA-co-MAA fibres revealed high BTB loading efficiency (>80 wt.%) and demonstrated prompt colour change and selective dye release at infected-like media (pH > 7). The synthesis of the thermally-crosslinked PAA network successfully enabled high water uptake ( = 1291 ± 48 - 2369 ± 34 wt.%) and swelling index ( = 272 ± 4 - 285 ± 3 a.%), in contrast to electrospun PAA controls. This dual device functionality was lost when the same building blocks were configured in a single-layer mesh of core-shell fibres, whereby significant BTB release (~70 wt.%) was measured even at acidic pH. This study therefore demonstrates how the fibrous configuration can be conveniently manipulated to trigger structure-induced functionalities critical to chronic wound management and monitoring.
Topics: Alanine; Biological Dressings; Bromthymol Blue; Color; Drug Resistance, Bacterial; Humans; Hydrogen-Ion Concentration; Nanoparticles; Polymethacrylic Acids; Water; Wound Healing; Wound Infection; Wounds and Injuries
PubMed: 30813559
DOI: 10.3390/s19050991 -
Proceedings of the National Academy of... Apr 1974Electron transport particles prepared from Mycobacterium phlei were depleted of bound coupling factors by washing with water in the absence of inorganic ions. The...
Electron transport particles prepared from Mycobacterium phlei were depleted of bound coupling factors by washing with water in the absence of inorganic ions. The depleted electron transport particles were void of latent ATPase activity and were capable of oxidation, but were unable to support coupled phosphorylation. Nevertheless, the depleted electron transport particles were capable of substrate-induced active transport of proline. Changes in pH in response to substrate oxidation were measured in normal and depleted electron particles with bromthymol blue. A bromthymol blue response upon substrate oxidation was not observed with depleted electron transport particles. The level of oxidative phosphorylation with succinate or NADH oxidation was not reduced in the presence of proline, and proline did not have an effect upon the proton gradients formed by the oxidation of either succinate or NADH.
Topics: Adenosine Triphosphatases; Anaerobiosis; Biological Transport, Active; Cell Membrane Permeability; Coloring Agents; Electron Transport; Hydrogen-Ion Concentration; Mycobacterium; NAD; Oxidation-Reduction; Oxidative Phosphorylation; Oxidative Phosphorylation Coupling Factors; Proline; Protons; Succinates
PubMed: 4364528
DOI: 10.1073/pnas.71.4.1202 -
Colloids and Surfaces. B, Biointerfaces Apr 2012The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence enables to sense the aggregation of cationic and anionic surfactants near...
The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence enables to sense the aggregation of cationic and anionic surfactants near the silica surface of Tb-doped silica nanoparticles (SN) in aqueous solutions. The Tb-centered luminescence of non-decorated SNs is diminished by the inner filter effect of both dyes. The decoration of the silica surface by cationic surfactants induces the quenching through the energy transfer between silica coated Tb(III) complexes and dye anions inserted into surfactant aggregates. Thus the distribution of surfactants aggregates at the silica/water interface and in the bulk of solution greatly affects dynamic quenching efficiency. The displacement of dye anions from the interfacial surfactant adlayer by anionic surfactants and phospholipids is accompanied by the "off-on" switching of Tb(III)-centered luminescence.
Topics: Absorption; Bromthymol Blue; Cations; Cetrimonium; Cetrimonium Compounds; Fluorescence; Hydrodynamics; Nanoparticles; Phenolsulfonphthalein; Phosphatidylglycerols; Phospholipids; Silicon Dioxide; Sodium Dodecyl Sulfate; Spectrum Analysis; Static Electricity; Surface-Active Agents; Terbium
PubMed: 22209651
DOI: 10.1016/j.colsurfb.2011.12.015 -
Applied and Environmental Microbiology Oct 2005Degeneration of cultivated strains of Flammulina velutipes is a serious problem. We developed a simple colorimetric method to detect degenerate strains by using a liquid...
Degeneration of cultivated strains of Flammulina velutipes is a serious problem. We developed a simple colorimetric method to detect degenerate strains by using a liquid medium supplemented with bromothymol blue and lactose. The ability of a strain to develop normal mushrooms could be determined by the color of the medium.
Topics: Agaricales; Bromthymol Blue; Colorimetry; Culture Media; Fruiting Bodies, Fungal; Industrial Microbiology; Japan; Lactose
PubMed: 16204563
DOI: 10.1128/AEM.71.10.6388-6389.2005 -
PloS One 2012Two members of the Cryptococcus neoformans-gattii species complex, the etiologic agents of cryptococcosis, can be differentiated by biological, biochemical, serological...
Two members of the Cryptococcus neoformans-gattii species complex, the etiologic agents of cryptococcosis, can be differentiated by biological, biochemical, serological and molecular typing techniques. Based on their differences in carbon and nitrogen utilization patterns, cost effective and very specific diagnostic tests using D-proline and canvanine-glycine-bromthymol blue (CGB) media have been formulated and are widely used for identification of the two species. However, these methods have yet to be tested for strains with confirmed molecular types to assess the degree of specificity for each molecular type in the two species. We collected global isolates of every major molecular type available and tested their patterns of nitrogen utilization. We confirmed specificity of the CGB test to be 100% regardless of molecular type while the D-proline test yielded 8-38% false negative results in three of the four C. gattii molecular types, VGI-VGIII. The utilization pattern of a new set of amino acids: D-alanine, L-tryptophan and L-phenylalanine, showed species specificity comparable to that of D-proline. We discovered that the transcription factor Gat1 (Are1) regulates the utilization of nitrogen differently between C. neoformans and C. gattii strains. Unlike in C. neoformans, expression of the genes encoding glycine decarboxylase complex in C. gatti was only partially suppressed by nitrogen catabolite repression in the presence of ammonium. GAT1 in C. neoformans controlled the induction of three of the four genes encoding the glycine decarboxylase complex when glycine was used as the sole nitrogen source while in C. gattii its regulation of these genes was less stringent. Moreover, while virulence of C. neoformans strains in mice was not affected by Gat1, the transcription factor positively influenced the virulence of C. gattii strain.
Topics: Animals; Cryptococcosis; Cryptococcus gattii; Cryptococcus neoformans; Fungal Proteins; GATA Transcription Factors; Gene Expression Profiling; Genetic Complementation Test; Genome, Fungal; Glycine Dehydrogenase (Decarboxylating); Mice; Mice, Inbred BALB C; Models, Biological; Nitrogen; Quaternary Ammonium Compounds; Reproducibility of Results; Species Specificity; Virulence
PubMed: 22479580
DOI: 10.1371/journal.pone.0034258 -
Chemical & Pharmaceutical Bulletin Jun 2010A sensitive and selective electrochemical method for simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) using an electropolymerized...
A sensitive and selective electrochemical method for simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) using an electropolymerized bromothymol blue (BTB)-modified glassy carbon electrode (GCE) was developed. The electrochemically synthesized film was investigated using electrochemical impedance spectroscopy and voltammetric methods. The electrochemical behavior of the polymer-modified electrode depends on film thickness, i.e., the electropolymyerization time. The poly-BTB-modified GCE shows excellent electrocatalytic activity toward the oxidation of AA, DA, and UA in phosphate buffer solution (pH 5.0). The voltametric peak separations of AA/DA, DA/UA, and AA/UA on this modified electrode are 118 mV, 298 mV, and 455 mV, respectively. Therefore the voltammetric responses of these three compounds can be resolved well on the polymer-modified electrode, and simultaneous determination of these three compounds can be achieved. In addition, this modified electrode can be successfully applied to determine AA and DA in injection and UA in urine samples without interference.
Topics: Ascorbic Acid; Biosensing Techniques; Bromthymol Blue; Carbon; Dopamine; Electrochemistry; Electrodes; Humans; Polymers; Sensitivity and Specificity; Uric Acid
PubMed: 20522988
DOI: 10.1248/cpb.58.788 -
Scientific Reports Jun 2015In chemistry, biology, medical sciences and pharmaceutical industries, many reactions have to be checked by transporting and mixing expensive liquids. For such purposes,...
In chemistry, biology, medical sciences and pharmaceutical industries, many reactions have to be checked by transporting and mixing expensive liquids. For such purposes, microfluidics systems consisting of closed channels with external pumps have been useful. However, the usage has been limited because of high fabrication cost and need for a fixed setup. Here, we show that open-capillary channels, which can be fabricated outside a clean room on durable substrates and are washable and reusable, are considerably promising for micro-devices that function without pumps, as a result of detailed studies on the imbibition of open micro-channels. We find that the statics and dynamics of the imbibition follow simple scaling laws in a wide and practical range; although a precursor film obeying a universal dynamics appears in the vertical imbibition, it disappears in the horizontal mode to make the design of complex micro-channel geometry feasible. We fabricate micro open-channel devices without any pumps to express the green fluorescent protein (GFP) by transporting highly viscous solutions and to accomplish simultaneous chemical reactions for the Bromothymol blue (BTB) solution. We envision that open-capillary devices will become a simple and low-cost option to achieve microfluidic devices that are usable in small clinics and field studies.
Topics: Bromthymol Blue; Green Fluorescent Proteins; Hydrogen-Ion Concentration; Microfluidics; Solutions
PubMed: 26103562
DOI: 10.1038/srep10263