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Several soil isolates from 1 g of soil sample were isolated and screened for the production of L-asparaginase. Primary screening was performed using rapid plate assay; dye indicator studies were conducted, and phenol red with 0.005% concentration was found to be optimum. The secondary screening was carried out using the Nesslerization method. The bacteria screened for L-asparaginase production with no glutaminase activity was identified as

The methods of the quantitative assay of the antiviral activity of interferons (IFNs) (type I, II or III) are very important during carrying out of the research of them, since they were found. Here a recombinant vesicular stomatitis virus expressing green fluorescent protein (GFP) (VSV/GFP) and MDBK cells were used to develop an antiviral assay (AVA) for IFNs. This method was carried out on a 96-well cell culture plate, and the half reduction of virus replication was quantified by assaying GFP. To quantify GFP, cell lysis buffer was directly added to the wells infected with VSV/GFP to lyse cells, the VSV/GFP was then inactivated, and relative fluorescence unit (RFU) of GFP was measured and used to calculate the antiviral activity. This method needed only one step instead of three steps in the staining method with naphthol blue black, medium with phenol red can be used, and it had good reproducibility. The GFP-containing samples could be stored at 4°C in a wet box for at least 1 week without affecting the assay results. In addition, the results obtained with this method were similar to those obtained with the staining method. In conclusion, a safe, rapid, convenient and low-cost AVA of IFN based on recombinant VSV/GFP was established.

Licorice has been used as an antitussive and expectorant herbal medicine for a long history. This work evaluated the activities of 14 major compounds and crude extracts of licorice, using the classical ammonia-induced cough model and phenol red secretion model in mice. Liquiritin apioside (1), liquiritin (2), and liquiritigenin (3) at 50 mg/kg (i.g.) could significantly decrease cough frequency by 30-78% (p .01). The antitussive effects could be partially antagonized by the pretreatment of methysergide or glibenclamide, but not naloxone. Moreover, compounds 1-3 showed potent expectorant activities after 3 days treatment (p .05). The water and ethanol extracts of licorice, which contain abundant 1 and 2, could decrease cough frequency at 200 mg/kg by 25-59% (p .05), and enhance the phenol red secretion (p .05), while the ethyl acetate extract showed little effect. These results indicate liquiritin apioside and liquiritin are the major antitussive and expectorant compounds of licorice. Their antitussive effects depend on both peripheral and central mechanisms.

Screening for the detection of carbapenemase-producing bacteria still encounters issues related to workflow, limit of detection, or qualitative interpretation. We developed a spectrophotometry-based version of the Carba NP phenol red assay (Nordmann et al., 2012) in a microtiter plate format, compatible with low bacterial cell counts. We were able to detect highly active carbapenemases such as KPC and IMP in 30min. A wider range of carbapenemases including OXA-48 were detected using higher inocula, still being competitive compared with currently available phenol red assays. Validation experiments of our test with a panel of 81 Enterobacteriaceae showed good performance with 93% of sensitivity and 92% of specificity. The compatibility of our routine-friendly protocol with automation offers great perspectives for high throughput screening in outbreak situations and/or in big laboratories.

Ion-permselective nanochannel-based sample preconcentration or electropreconcentration has been demonstrated as an effective technique for concentrating charged analytes at the interface between a micro- and nanochannel. The anion-selective electropreconcentration involves extraction of hydroxide in the preconcentrated sample plug, resulting in pH decrease. We investigated the pH change in a microchannel using charged pH indicators with different conditions including running buffer pH, sample channel electric field, and salt concentration. The anion-selective preconcentration showed pH decrease from 11 to under 7 in the preconcentrated sample plug. Therefore, careful design and interpretation are required with pH-dependent experiments such as analyzing enzyme or antibody characteristics. The pH change could be mitigated by reducing the sample channel electric field and/or increasing salt concentration in the buffer.

We describe an electrochemical measurement technique that enables bioelectronic measurements of reporter proteins in living cells as an alternative to traditional optical fluorescence. Using electronically programmable microfluidics, the measurement is in turn used to control the concentration of an inducer input that regulates production of the protein from a genetic promoter. The resulting bioelectronic and microfluidic negative-feedback loop then serves to regulate the concentration of the protein in the cell. We show measurements wherein a user-programmable set-point precisely alters the protein concentration in the cell with feedback-loop parameters affecting the dynamics of the closed-loop response in a predictable fashion. Our work does not require expensive optical fluorescence measurement techniques that are prone to toxicity in chronic settings, sophisticated time-lapse microscopy, or bulky/expensive chemo-stat instrumentation for dynamic measurement and control of biomolecules in cells. Therefore, it may be useful in creating a: cheap, portable, chronic, dynamic, and precise all-electronic alternative for measurement and control of molecules in living cells.

This work was carried out in the field of water treatment using advanced oxidation processes (AOPs), especially photolysis of carboxylic acid that leads to the formation in situ of hydroxyl radical (·OH). Cresol red (CR) degradation induced by organic acids/UV system was investigated in aqueous solution. The preliminary study of CR-organic acid mixture in the dark and at room temperature allowed confirming the absence of interaction under our experimental conditions. However, upon irradiation at 365 nm, the proportion of elimination of CR was 89% after 5 h of irradiation. Indeed, the CR degradation efficiency depends on the acid concentration and the pH of the medium. The concentration of acid is optimized to the 5 × 10

Thermochromic materials exhibit a color change in response to a change in temperature. Creating nontoxic microcapsules containing thermochromic materials for applications in ink and film materials is historically challenging. In this study, we develop a nontoxic chlorophenol red (CPR)–water thermochromic system and its microcapsules with silicone shells via a reaction between water and octadecyltrichlorosilane (OTS) at the interface of a w/o emulsion. The obtained microcapsules exhibit a clear color change with full reversibility and are successfully used as inks by screen printing and as additives in films. Nontoxicity of both microcapsules and films is demonstrated through cell cytotoxicity assays. These features make these novel materials applicable to the next generation of intelligent sensors, coating, and food packaging materials.

Purpose Noninvasive analyses of tear fluid from humans and animal models in clinical and research settings most commonly use absorbent material for collection and processing. Still, the impact of these analytical techniques on tear chemical analyses remains largely unknown. The purpose of this study was to quantify the impacts of phenol red thread fiber-based tear sample collection and processing on the primary amine content. Methods Human tears were collected by placing the folded end of phenol red thread on the palpebral conjunctiva of the right eye for 20 seconds. The wetted thread was then processed using elution or extraction, and capillary electrophoresis with light-emitting diode-induced fluorescence detection was used for analysis and quantitation. Results Distinct processing methods impacted tear analysis differently. Primary amines adsorbed onto the thread partitioned in a chromatographic manner and thus any single portion of the wetted thread might not be representative of the whole sample. Quantitative assessment of five small molecule standards after on-thread processing showed significant overestimation of the actual concentration, with increased accuracy for larger volume samples. Yet collection of larger tear volumes introduced error in volume determination owing to evaporation and reduced small molecule separation resolution. Conclusions These results indicated that absorption-based tear fluid collection and processing significantly alter chemical content analysis, suggesting that the impacts of methods used should be regularly evaluated to standardize results drawn from different studies. Translational relevance This study identifies potential inconsistencies and inaccuracies in tear analyses that are widespread across the published literature and clinical care.

KAYNAK, Mustafa Sinan/0000-0003-2917-2407, WOS: 000534281500009, PubMed: 32416593, One of the most common techniques for assessing the intestinal absorption characteristics of drugs is single-pass intestinal perfusion (SPIP) method. Metoprolol tartrate (MT, reference standard) and phenol red (PR, zero permeability marker) are the compounds that are normally used in SPIP studies. the aim of this study was to develop a reverse phase high-performance liquid chromatography (RP-HPLC) method combined with UV-detection for the simultaneous determination of MT and PR in the perfusion medium used in SPIP experiments. Elution was performed using a Restek Raptor C18 column (5 mu m, 4.6 mm x 250) at a temperature of 25 degrees C. the mixture of the mobile phase consisted of (MeOH):(Phosphate buffer solution, PBS), (20 mM, pH 3.0 adjusted with ortho-phosphoric acid),(55:45, v/v). Flow rate and column temperature were set at 1.2 mL min(-1) and 25 degrees C, respectively. MT and PR were injected as 20 mu L into the HPLC system. UV detection was performed at 227 nm. the obtained retention times were reported as 2.89 and 3.80 min for MT and PR, respectively. the developed RP-HPLC method was validated according to Q2(R1) guideline of the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). the method was linear within the range of 2-50 mu g(-1) for PR and 10-75 mu g(-1) for MT. the developed RP-HPLC method was successfully applied on determination of MT and PR in perfusion medium. the developed method could be helpful for researchers working on in-situ rat intestinal permeability studies and it could be easily modified on further studies.

OBJECTIVE The purpose of this study is to evaluate a group of young commercially available Skinny pigs, to gain information regarding ocular findings in this breed of guinea pig. Comparisons of ocular findings are to be made between Skinny pigs and haired guinea pigs. ANIMAL STUDIED Ten haired guinea pigs and ten Skinny pigs were examined. PROCEDURE A complete ophthalmic examination including Schirmer tear test-II (STT-II), phenol red thread test (PRTT), rebound tonometry with TonoVet PLUS, Fluorescein and Rose Bengal stain was performed. Microbiology swabs for aerobic bacterial growth were collected from conjunctiva of both eyes prior to the ophthalmic examination. RESULTS The ophthalmic examination revealed seven abnormal ocular findings: trichiasis, mucopurulent discharge, hyperemia/chemosis of the conjunctiva, corneal fibrosis, corneal vascularization, and foreign body on the cornea or conjunctiva. Skinny pigs had a significantly higher amount of mucopurulent discharge (P = .0133) and a significantly higher STT-II (P

Bisphenol A (BPA) is commonly present in plastics used for food storage and preservation. The release of BPA from these products results in a permanent human exposition to BPA; however, the quality and quantity of BPA adverse effects remain a matter of controversy. The common presence of BPA in the human environment and the controversies concerning the relations of human exposition to BPA and cancer incidence justify the research on the interactions between BPA and pro-metastatic signaling in cancer cells. Here, we describe a novel BPA-reactive signaling axis that induces the epithelial-mesenchymal transition (EMT) in lung adenocarcinoma A549 cells. BPA exerted negligible effects on their properties in a wide range of concentrations (10 nM - 100 nM), whereas it considerably induced A549 invasiveness at high concentrations (10 μM). The BPA-induced EMT was illustrated by morphologic changes, E/N-cadherin switch and vimentin/Snail-1/connexin(Cx)43 up-regulation in A549 populations. It was followed by enhancement of A549 drug-resistance. Corresponding effects of BPA were observed in prostate cancer cell populations. Concomitantly, we observed increased levels and perinuclear accumulation of estrogen-related receptor gamma (ERRγ) in BPA-treated cells, its interactions with Cx43/Snail-1, and the corresponding effects of phenol red on A549 cells. Collectively, these data identify a novel, pro-metastatic Snail-1/Cx43/ERRγ signaling pathway. Its reactivity to BPA underlies the induction of cancer cells' invasiveness in the presence of high BPA concentrations in vitro. Thus, the chronic exposition of cancer cells to extrinsic and intrinsic BPA should be considered as a potential obstacle in a cancer therapy.

Using the advantages of phenol red, a signal enhancer, and bovine serum albumin (BSA), a stabilizer of horseradish peroxidase (HRP), added in HRP enzyme reaction of Amplex Red and H2O2, highly sensitive 1,1′-oxalyldiimidazole chemiluminescence enzyme immunoassay (ODI-CLEIA) was developed to rapidly quantify trace levels of carcinoembryonic antigen (CEA) in human serum. Phenol red acts as an enhancer in ODI-CLEIA while BSA supported rapid and stable activation of HRP. The CL emission of resorufin formed from the HRP enzyme reaction in the presence of BSA and phenol red was about 70-fold brighter than that in the absence of both materials. ODI-CLEIA in the presence of BSA (1.5 mg/ml).and phenol red (1 mM) was able to rapidly analyze CEA in human serum with the wide linear calibration curve (2.5–100 ng/ml). The limit of detection (LOD = 3σ/slope) of ODI-CLEIA was as low as 0.19 ng/ml. Additionally, it was confirmed that the accuracy, precision, and reproducibility of ODI-CLEIA in the presence of BSA and phenol red were good with the statistically acceptable error range.

A non-contact real time pH measurement using fully modular optical parts is described for phenol-red medium cell cultures. The modular parts can be sterilized, and once the measurement is started at the beginning of culture, no recalibration or maintenance is needed till the end of the culture. Measurements can be carried out without any special manual attention. The modular assembly of LED and sensor cassettes is unique, robust, reusable and reproducible. pH is measured in an intact closed flow system, without wasting any culture medium. A special pump encapsulation enables the system to be effortlessly functional in extremely humid incubator environments. This avoids lengthy sample tubings in and out of the incubator, associated large temperature changes and CO 2 buffering issues. A new correction model to compensate errors caused e.g. by biolayers in spectrometric pH measurement is put-forward, which improves the accuracy of pH estimation significantly. The method provides resolution down to 0.1 pH unit in physiological pH range with mean absolute error 0.02.

The collection of tears for chemical composition analysis is complicated by both the difficulty in sampling the tear film and the relatively low microliter volumes available for analysis. The experiments in this study are focused on the demonstration of a method for determining amino acids from tear samples. Phenol red thread was used to absorptively collect tear fluid for qualitative and quantitative analyses of amino acids in basal, reflex, and emotional tears. The thread is also used as a support for sample preparation followed by elution with a buffer. The phenol red indicator on the thread turns from yellow to red with 15-s tear absorption and allows accurate volume measurement from 100 nL to over 1 μL. Derivatization of amino acids was performed directly on the thread with primary amine reactive fluorescamine for fluorescence detection. Analyte elution was performed via centrifugation with the thread in a pipet tip suspended in a centrifuge tube. Collected tear eluate was analyzed via capillary electrophoresis with LED-induced fluorescence. Glycine, glutamate, and aspartate were baseline resolved and used for method characterization. Recoveries were at 50 % for a single derivation and elution step but average recoveries near 90 % were found with two-step processing. Glutamate and aspartate are shown to be stable stored on thread for 3 days. Basal, reflex, and emotional tears were analyzed from three subjects showing distinct amino acid profiles for each tear type. The demonstration of this method may facilitate the development of routine tear compositional analysis to assess ocular health. Graphical Abstract Schematic drawing of thread-based tear collection and quantitative analysis.

In spite of numerous advantages, transdermal drug delivery systems are unfeasible for most drugs because of the barrier effect of the stratum corneum. Ionic liquids were recently used to enhance transdermal drug delivery by improving drug solubility. In the present study, safe and effective ionic liquids for transdermal absorption were obtained as salts generated by a neutralization reaction between highly biocompatible aliphatic carboxylic acids (octanoic acid or isostearic acid) and aliphatic amines (diisopropanolamine or triisopropanolamine) (Medrx Co., Ltd., 2009). The mechanism of skin permeability enhancement by ionic liquids was investigated by hydrophilic phenol red and hydrophobic tulobuterol. Further, the skin permeation enhancing effect was remarkably superior in the acid excess state rather than the neutralization state. Infrared absorption spectrum analysis confirmed that ionic liquids/aliphatic carboxylic acid/aliphatic amine are coexisting at all mixing states. In the acid excess state, ionic liquids interact with aliphatic carboxylic acids via hydrogen bonds. Thus, the skin permeation enhancing effect is not caused by the ionic liquid alone. The "liquid salt mixture," referred to as a complex of ingredients coexisting with ionic liquids, forms a molecular assembly incorporating hydrophilic drug. This molecular assembly was considered an effective and safety enhancer of transdermal drug permeation.

Relying on the specific coordination of Ag+ and mismatched cytosine-cytosine (C–C), the high-efficiency inhibition of urease by Ag+ ion, and the rapid and sensitive response of phenol red to pH, a sensitive ratiometric sensor has been designed for visual detection of human immunodeficiency virus gene (HIV DNA). This sensor utilizes the HIV DNA to initiate catalytic hairpin assembly (CHA) process, releasing Ag+ to inhibit subsequent urease-catalyzed urea hydrolysis and prevent the pH of the solution from rising. The CHA process and the absorbance ratio of phenol red at different wavelengths (A559/A432) amplify the signal, allowing the sensor to detect HIV DNA from 10 to 130 nM in a sensitive and highly selective manner with a low detection limit of 7.8 nM. In addition, this sensor can visually distinguish different concentrations of HIV DNA within a certain range and possesses a good recovery in 1% of serum samples, which will provide new ideas for biosensor design, dipstick test, blood test, and other clinical disease prevention.

Intense pulsed light (IPL) has been used therapeutically in a number of clinical settings and has been shown to have a photobiomodulatory effect on connective tissue cells, such as those derived from skin and tendon. In vitro cell culture models are essential tools preclinically in investigating such treatment modalities, as they help in optimising parameters for successful treatment. However, as culture system components have been reported to absorb part of the irradiated energy, which in turn has a bearing on the amount of light reaching the cells, it is important to establish specific parameters for the particular in vitro model used. This study, therefore, investigates the effect of our tissue culture system components on the IPL energy delivered. Individual wells of multi-well plates were irradiated with IPL at different device settings and under variable culture conditions (e.g. in the absence or presence of cell culture media with or without the pH indicator dye, phenol red), and the energy lost through the culture system determined. Our data demonstrated that the IPL device delivered significantly lower outputs than those published, and energy absorption by the culture equipment would further reduce fluencies delivered to the cell monolayer. Furthermore, energy absorption by media containing phenol red was marginally greater than clear media and resulted in only a small increase in temperature, which would not be harmful to cells. The use of phenol red-containing media therefore is valid and physiologically relevant when examining light-culture system interactions.

The use of coliforms and Escherichia coli as indicator species for assessing the quality of water is well established and a large variety of methods based on β-galactosidase (B-GAL) activity, inherent to the microbes within this classification, have arisen to enable their detection and enumeration. Chlorophenol red (CPR) is widely used as a chromogenic label, but its capacity for translation to electroanalytical devices has yet to be fully explored. The CPR moiety is capable of undergoing oxidation at carbon substrates (+0.7 V) giving rise to a variety of phenolic intermediates. Electrochemical, XPS and enzymatic techniques were employed to characterise the underpinning chemistry and the intermediate identified as a 1,2-quinone derivative in which the chlorine substituent is retained. The latter was found to accumulate at the electrode and, in contrast to the parent CPR, was found to be detected at a significantly less positive potential (+0.3 V). Bacterial hydrolysis of a CPR labelled substrate was demonstrated with the 1,2-quinone oxidation product found to accumulate at the electrode and detected using square wave voltammetry. Proof of concept for the efficacy of the alternative electrode pathway was established through the detection of E.coli after an incubation time of 2.5 h with no interference from the labelled substrates.

Bortezomib (BTZ), as a proteasome inhibitor, has been used for treatment of patients with relapsed/refractory multiple myeloma and mantle cell lymphoma. BTZ is available for intravenous injection or subcutaneous administration. In this study, for evaluating the potential of BTZ oral delivery, intestinal permeability of BTZ was determined using in situ single-pass intestinal perfusion (SPIP) technique and the perfused solutions were analyzed using a validated HPLC-UV method. The chromatographic separation was performed using a C18 column via isocratic mode at a flow rate of 0.5 mL/min at 270 nm. The mobile phase was a mixture of methanol/deionized water (50:50% v/v) with 0.1% glacial acetic acid. The results indicated that calibration curves were linear (r2 ˃0.99) in a concentration range of 1.65–5 µg/mL for BTZ and 8.33–25 µg/mL for phenol red. A limit of quantitation of 1.03 and 6.67 µg/mL was obtained for BTZ and phenol red, respectively. The recovery values were in the range of 96.5–105.4% for BTZ, and 88–99.2% for phenol red. The relative standard deviations (RSD) were ≤4.9% for BTZ and ≤7% for phenol red. Stability studies indicated that the working standard solution is stable over a period of 48 h at room temperature. Finally, an effective permeability (Peff) value of (3.36±0.5)×10−5 cm/sec (mean±SEM) was achieved for BTZ. Moreover, it was predicted that BTZ belongs to the biopharmaceutical class ІІІ.

Detection of α-thalassemia-1 (α-thal-1) carriers provides valuable insight for genetic consulting in prevention and control programs for couples who are at risk of conceiving a fetus with severe thalassemia, both Hb Bart's hydrops fetalis and hemolytic Hb H disease. The traditional method is complicated, time-consuming and requires high instrument cost and expertise. Loop-mediated isothermal amplification (LAMP) based on pH-sensitive dye technology, shows all the characteristics required of a real-time analysis with simple operation for potential use in the clinical diagnosis of high incidence α-thal-1 [Southeast Asian (SEA) or -

This study tested the hypothesis that the presence of prostaglandin E2 in seminal plasma would aid in the transport of phenolsulfonphthalein (PSP) across the uterotubal junction. Five mares in estrus were inseminated during estrus with PSP dissolved in phosphate-buffered saline and during the subsequent estrus with PSP added to a standard insemination dose. Serum and urine samples were obtained at hours 0, 1, 2, and 3 following treatment and examined for the presence of PSP. Phenolsulfonphthalein could not be detected in any of the urine samples collected from mares following either treatment. None of the serum samples collected following intrauterine installation of PSP in PBS contained PSP. Phenolsulfonphthalein was detected in serum samples from 1 mare following insemination with semen containing PSP. Components in seminal plasma such as PGE2 did not facilitate the transport of PSP across the uterotubal junction as had been hypothesized.

The goal of this study was to create a mass transport model (MTM) model for gastric emptying and upper gastrointestinal (GI) appearance that can capture the in vivo concentration-time profiles of the nonabsorbable drug phenol red in solution in the stomach and upper small intestine by direct luminal measurement while simultaneously recording the contractile activity (motility) via manometry. We advanced from a one-compartmental design of the stomach to a much more appropriate, multi-compartmental 'mixing tank' gastric model that reflects drug distribution along the different regions of the stomach as a consequence of randomly dosing relative to the different contractile phases of the migrating motor complex (MMC). To capture the intraluminal phenol red concentrations in the different segments of the GI tract both in fasted and fed state conditions, it was essential to include a bypass flow compartment ('magenstrasse') to facilitate the transport of the phenol red solution directly to the duodenum (fasted state) or antrum (fed state). The fasted and fed state models were validated with external reference data from an independent aspiration study using another nonabsorbable marker (paromomycin). These results will be essential for the development and optimization of computational programs for GI simulation and absorption prediction, providing a realistic gastric physiologically-based pharmacokinetic (PBPK) model based on direct measurement of gastric concentrations of the drug in the stomach. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS vol:129 pages:162-174 ispartof: location:Netherlands status: published

To analyze the effects of phenol red at various pH values on the Sabin type 2 inactivated polio vaccine (sIPV2), several biophysical techniques were used to evaluate the particle size and capsid protein for conformation. sIPV2's size was assessed via transmission electron microscopy and dynamic light scattering. The effects of various pH values (from 4.0 to 7.0) on the biophysical characters of sIPV2 particles in solution were determined by dynamic light scattering and zeta potential. The results clearly indicated that aggregation and instability occurred in the solution of sIPV2 particles at a pH of 6.0. Under similar conditions, by dynamic light scattering and zeta potential, the virus particles in solution showed more dispersion and were stable with the addition of 0.05 mM phenol red. According to circular dichroism and intrinsic tryptophan fluorescence data, it was observed that the secondary and tertiary structures of the sIPV2 particles were more stable with the protection of phenol red. At a pH below 6.0, the sIPV2 solution with phenol red had more D-antigen content, which was confirmed by enzyme-linked immunosorbent assay and rat experiments. These results strongly suggested that phenol red improved the pH stability of the sIPV2. The study indicated the potential of phenol red in preserving vaccine potency of the sIPV2 at various pH values.

The aim of this study was to investigate the effects of different media with or without phenol red or the antioxidant trolox on the successful vitrification of feline ovarian tissue. In a first experiment, ovarian cortical pieces from three cats were vitrified in solutions of Roswell Park Memorial Institute (RPMI)-1640 medium, Minimum Essential Medium, Dulbecco's modified Eagle's medium, or Tissue Culture Medium 199 as basic medium, supplemented or not with 50 μM of trolox, all containing 40% ethylene glycol (EG) and 1 M of sucrose. RPMI-1640 (phenol red-free) without trolox was the only medium that preserved the percentage of morphologically normal preantral follicles similar to control (80%). The main difference between RPMI-1640 and the other media was the absence of phenol red and CaCl2. In a second experiment, ovarian cortical pieces from three cats were vitrified in a solution containing RPMI-1640 as basic medium, 40% EG, 1 M of sucrose, supplemented or not with phenol red or CaCl2 alone, or in combination. It was observed that phenol red supplementation led to follicular degeneration. Finally, to evaluate the interaction between phenol red and the cryoprotectant agent (i.e., EG), ovarian tissue was exposed to RPMI-1640 supplemented with phenol red and EG at different concentrations (10%, 20%, or 40%). There was an inverse relationship between EG concentration and free phenol red in the medium after exposure. It is suggested that vitrification of feline ovarian tissue should be performed in a phenol red-free medium. Medium supplementation with 50 μM of trolox was deleterious for follicular morphology.

Bromophenol red, known as chemical indicator, was found to act as a novel potent signal enhancer of the peroxidase-catalyzed luminol-H2O2 chemiluminescent (CL) reaction. It was found interestingly that bovine serum albumin (BSA) played a role in the enhanced chemiluminescent reaction (ECR). The addition of 2.5 mg mL(-1) BSA into bromophenol red-enhance CL system showed 36 times stronger CL signal than that without addition of BSA. Mechanism study showed that the luminophors in the ECR were still 3-aminophthalate ion in an excited state (3-APA*). In addition, singlet oxygen ((1)O2) and hydroxyl radical ((∙)OH) played a role in the ECR. The possible mechanism was discussed in the present study. The effect of pH, reaction time, and concentration of bromophenol red, BSA, luminol, and H2O2 on CL intensity of the peroxidase-catalyzed CL reaction was studied. The detection limit value (LOD) of HRP and streptavidin-modified HRP in the proposed ECR with bromophenol red and BSA was 0.20 ng mL(-1) and 0.05 ng mL(-1), respectively. This novel luminol-H2O2-HRP-bromophenol red-BSA CL system was applied to the CL detection of sequence-specific DNA based on a magnetic separation process. As low as 0.4 fmol of target DNA could be sensitively detected using the proposed CL system without any amplification process. The obtained results demonstrate very promising perspectives for using bromophenol red and BSA to improve the sensitivity of CL detection of sequence-specific DNA. In addition, this novel ECR system can also be generalized for CL immunoassay, CL western blotting, and so on.

Microtiter plates (MTP) and automatized techniques are increasingly applied in the field of biotechnology. However, the susceptibility of MTPs to edge effects such as thermal gradients can lead to high variation of measured enzyme activities. In an effort to enhance experimental reliability, to quantify, and to minimize instrument-caused deviations in enzyme kinetics between two MTP-readers, we comprehensively quantified temperature distribution in 96-well MTPs. We demonstrated the robust application of the absorbance dye cresol red as easily applicable temperature indicator in cuvettes and MTPs and determined its accuracy to ±0.16°C. We then quantified temperature distributions in 96-well MTPs revealing temperature deviations over single MTP of up to 2.2°C and different patterns in two commercial devices (BioTek Synergy 4 and Synergy Mx). The obtained liquid temperature was shown to be substantially controlled by evaporation. The temperature-induced enzyme activity variation within MTPs amounted to about 20 %. Activity deviations between MTPs and to those in cuvettes were determined to 40 % due to deviations from the set temperature in MTPs. In conclusion, we propose a better control of experimental conditions in MTPs or alternative experimental systems for reliable determination of kinetic parameters for bioprocess development.

Falconiformes are active searchers and hunters that require visual precision to catch their prey and survive in the wild. Despite this, ocular disease is likely to be underdiagnosed in these species, at least in part because of limited proven diagnostic methods and lack of published scientific data. Tear film deficiency is recognized as an important ocular surface disease in dogs but has not been well evaluated in birds. To evaluate the phenol red thread (PRT) tear test as an alternative method to the Schirmer tear test (STT) for determining tear production in Falconiformes, we assessed the PRT tear test twice for each eye in 21 birds from the genus Falco. The mean PRT test values for the right (OD) and left (OS) eyes were OD=30.2±4.6 mm/15 s and OS=29.1±3.7 mm/15 s, with an overall PRT test value for both eyes (OU) of 30.6±4.2 mm/15 s. Good reproducibility was seen with the PRT test as shown by the strong positive correlation between the first and second tests in the birds. The PRT test method provides repeatable results that are easy to obtain, easy to read, and achieved under the same conditions as the STT.

The authors describe a colorimetric method for the determination of Hg2+ ions based on the inhibition of the activity of the enzyme urease. The pH value of solution increases when urease hydrolyzes urea, which can be visualized by adding a pH indicator such as Phenol Red (PhR). Mercaptoethanol as a typical thiol is added to the system to improve selectivity because it binds metal ions and then - unlike the Hg2+ mercaptoethanol complex - does not inhibit urease. Hence, the color of the pH indicator PhR turns from yellow to pink as the solution becomes alkaline. The Hg2+ mercaptoethanol complex, in contrast, strongly inhibits urease and the color of the solution remains yellow. The findings were used to design a photometric assay based on the measurement of the ratio of absorptions of PhR at 558 nm and 430 nm. It has a linear response over the 25 to 40 nM Hg2+ concentration range and a 5 nM detection limit. This is well below the guideline values of Hg2+ specified by the US Environmental Protection Agency and the World Health Organization for drinking water (10 nM and 30 nM, respectively). The method was employed to the determination of Hg2+ in water samples spiked with 10 nM levels of Hg2+ where color changes still can be observed visually.

An original scheme for sensitive absorption measurements, particularly well-suited for low analyte concentrations, is presented. The technique is based on multiscattering-enhanced absorption spectroscopy (MEAS) and benefits from the advantages of conventional absorption spectroscopy: simplicity, rapidity, and low costs. The technique relies on extending the optical path through the sensing volume by suspending dielectric beads in the solution containing the analytes of interest, resulting in multiple scattering of light, which increases the optical path length through the sample. This way, a higher sensitivity and lower limit of detection, compared to those of conventional absorption spectroscopy, can be achieved. The approach is versatile and can be used for a broad variety of analytes. Here, it is applied to the detection of phenol red, 10 nm gold nanoparticles, and envy green fluorescence dye; the limit of detection is decreased by a factor of 7.2 for phenol red and a factor of 3.3 for nanoparticles and dye. The versatility of this approach is illustrated by its application in increasing the sensitivity of colorimetric detection with gold nanoparticle probes and a commercially available hydrogen peroxide bioassay. The influence of different parameters describing the scattering medium is investigated in detail experimentally and numerically, with very good agreement between the two. Those parameters can be effectively used to tailor the enhancement for specific applications and analytes.

Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing p electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C=C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetra-hedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C pi* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O-2 adsorption and electron transfer from carbon to O-2, which enhances O-2 activation. The O-2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media.

OBJECTIVES: The strip meniscometry test (SMT) is a novel method for quantitative measurement of tear volume with only five seconds. We aimed to evaluate clinical correlations of SMT with the gold standard Schirmer tear test (STT) and phenol red thread test (PRT) in dogs, including normal and tear‐deficient eyes. ANIMALS STUDIED: Left eyes from 621 outpatient dogs with and without ocular disorders were evaluated. PROCEDURES: Each subject underwent SMT, PRT, and STT without topical anesthesia in the described order with five‐minute intervals. The total population was divided into four groups by classifying tear deficiency severity based on STT results: “severe” (0‐5 mm/min), “moderate” (6‐10 mm/min), “subclinical” (11‐14 mm/min), and “normal” (15 or more mm/min). RESULTS: The strongest correlation coefficient was found between SMT‐STT (0.676), followed by PRT‐STT (0.637) and SMT‐PRT (0.600) pairs. Mean(SD) scores of SMT, PRT, and STT in total population were 9.47 (4.08) mm/5 s, 33.30 (8.52) mm/15 s, and 16.47 (7.01) mm/min. Significant differences were found among STT‐classified groups, both using SMT and PRT results. Receiver operating characteristic (ROC) curves revealed that SMT better agreed with STT than PRT; agreement increased with increasing STT severity. A cutoff for SMT was identified at 10 mm/5 s to discriminate normal eyes from tear‐deficient eyes, yielding high sensitivities and acceptable specificities. CONCLUSIONS: SMT could be superior to PRT for discriminating tear‐deficient eyes. The high sensitivity of SMT could be useful as an initial diagnostic tool to rule out normal eyes with the short testing time.

Problems with indoor husbandry and immunological challenges are some of the stressors that broilers may face which can affect production. Infectious diseases can compound the effects of excessive concentrations of ammonia causing respiratory and ocular inflammation and increased lacrimal production in broiler chickens. The objectives of this investigation were to establish normal values of tear production in chicks and compare the practicality of the different methods. Palpebral fissure length (PFL) and tear production were evaluated in Cobb 500 chicks at 5 d old and then at 5 d of age by the following methods: modified Schirmer's test I (mSTT1), phenol red cotton thread tear test (PRCTTT), and standardized endodontic absorbent paper point test (EAPPTT). Ten chicks at the age of 5 and 42 d were evaluated for each method. In addition, at 42 d, when the palpebral fissure permitted, a regular-sized Schirmer tear test I (STT1) was performed in another group of 10 chickens. Overall, PFL and the secretion of the aqueous phase of the tear film increased with age. Mean mSTT1 results were 5.00 ± 1.83 mm and 10.45 ± 2.58 mm for 5- and 42-d-old chicks, respectively. Mean PRCTTT results were 12.37 ± 1.80 mm and 25.58 ± 4.8 mm for 5- and 42-d-old chicks, respectively. Mean EAPPTT results were 7.13 ± 0.72 mm and 12.03 ± 0.92 mm for 5- and 42-d-old chicks, respectively. Mean STT1 for 42-d-old chicks was 11.40 ± 2.60 mm. Results obtained with endodontic paper points showed the lowest coefficient of variation and investigators found the test easier to perform. These values reported for broilers at different ages may be applied in poultry ophthalmology to help the diagnosis of lacrimal production disorders and to detect early disease symptoms that could cause economic losses in poultry production.

In Expt 1, a Zn-unsupplemented basal diet (control) and the basal diet supplemented with one of four different Zn sources, including ZnSO4, Zn-amino acid chelate with a weak chelation strength (Zn-AA W), Zn-protein chelate with a moderate chelation strength (Zn-Pro M) and Zn-protein chelate with a strong chelation strength (Zn-Pro S) were fed to broiler chickens from days 14 to 28. On day 28, Zn content in plasma from the hepatic portal vein increased (P4P4PP>0·05) and Zn-AA W(P4. These findings indicate that organic Zn absorption (especially Zn-Pro S) in intact living broilers was more effective than that of inorganic Zn; organic Zn absorption in the ligated duodenal segment was a saturable carrier-mediated process similar to that of ZnSO4. Moreover, except for MT, there might be other Zn transporters involved in Zn absorption that are affected by different Zn sources.

Gastrointestinal (GI) fluid volume and its dynamic change are integral to study drug disintegration, dissolution, transit, and absorption. However, key questions regarding the local volume and its absorption, secretion, and transit remain unanswered. The dynamic fluid compartment absorption and transit (DFCAT) model is proposed to estimate in vivo GI volume and GI fluid transport based on magnetic resonance imaging (MRI) quantified fluid volume. The model was validated using GI local concentration of phenol red in human GI tract, which was directly measured by human GI intubation study after oral dosing of non-absorbable phenol red. The measured local GI concentration of phenol red ranged from 0.05 to 168 μg/mL (stomach), to 563 μg/mL (duodenum), to 202 μg/mL (proximal jejunum), and to 478 μg/mL (distal jejunum). The DFCAT model characterized observed MRI fluid volume and its dynamic changes from 275 to 46.5 mL in stomach (from 0 to 30 min) with mucus layer volume of 40 mL. The volumes of the 30 small intestine compartments were characterized by a max of 14.98 mL to a min of 0.26 mL (0–120 min) and a mucus layer volume of 5 mL per compartment. Regional fluid volumes over 0 to 120 min ranged from 5.6 to 20.38 mL in the proximal small intestine, 36.4 to 44.08 mL in distal small intestine, and from 42 to 64.46 mL in total small intestine. The DFCAT model can be applied to predict drug dissolution and absorption in the human GI tract with future improvements.