salicylates and 3-5-dinitrosalicylic-acid

Use of the 3,5-dinitrosalicylic acid reagent allows the simple, rapid quantification of reducing sugars. The method can be used for analysis of biological samples or in characterization of enzyme reactions, as new reducing ends are generated when a polysaccharide substrate undergoes hydrolytic cleavage. Presented here is an application of the method in measuring the kinetics of a glycoside hydrolase reaction, including the optimization of the DNSA reagent, and the production of a standard curve of absorbance versus sugar concentration.

Topics: Carbohydrates; Glycoside Hydrolases; Kinetics; Salicylates; Substrate Specificity

The aim was to determine inhibition of human α-amylase activity by (poly)phenols using maltoheptaoside as substrate with direct chromatographic product quantification, compared to hydrolysis of amylose and amylopectin estimated using 3,5-dinitrosalicylic acid. Acarbose exhibited similar IC

Topics: Acarbose; alpha-Amylases; Amylopectin; Amylose; Catalytic Domain; Catechin; Chromatography, Ion Exchange; Flavones; Humans; Hydrolysis; Hydrolyzable Tannins; Oligosaccharides; Polyphenols; Salicylates; Starch; Sugars

3,5-Dinitrosalicylic acid hydrazide (DNSAH) is the metabolite of the antibacterial nitrofuran nifursol. A simple and accurate analytical method to determine DNSAH levels in honey by solid-phase extraction-ultraperformance liquid chromatography-tandem mass spectrometry has been established. The honey sample was hydrolyzed under acidic conditions and derivatized with 2-nitrobenzaldehyde in the dark for 16 h, followed by solid-phase extraction and column chromatography. Detection was performed with an electrospray ionization source and multiple reaction monitoring mode and was quantified by the internal standard method. The detection and quantitative limits of DNSAH in honey were 0.1 and 0.3 μg/kg, respectively. Good linear relationships between peak areas and mass concentrations of the analyte were achieved in the range of approximately 0.1 to 200 μg/L, with the correlation coefficient >0.9991. Under the concentration levels of 0.2, 0.5, 1.0, and 2.0 μg/kg, the average recovery rate were between 98.5 and 102.3%, and the relative standard deviations were between 1.1 and 5.4%. The results indicate that the method is simple, rapid, sensitive, and reproducible and can be used to determine DNSAH levels in different types of honey.

Topics: Chromatography, High Pressure Liquid; Chromatography, Liquid; Food Contamination; Honey; Salicylates; Solid Phase Extraction; Tandem Mass Spectrometry

Transformation of renewable biomass into value-added chemicals and biofuels has evolved to be a vital field of research in recent years. Accurate estimation of reducing sugars post pretreatment of lignocellulosic biomass has been very inconsistent. For a few decades, 3,5-dinitrosalicylic acid (DNS) assay has been widely employed for the estimation of reducing sugars derived from pretreatment of lignocellulosic biomass. This assay tests for the presence of free carbonyl group (C=O), the so-called reducing sugars. This involves the oxidation of the aldehyde functional group present to the corresponding acid while DNS is simultaneously reduced to 3-amino-5-nitrosalicylic acid under alkaline conditions. However, the presence of other active carbonyl groups can potentially also react with DNS leading to incorrect yields of reducing sugars. Therefore, a detailed study has been carried out to evaluate the influence of active carbonyl compounds like furfural and 5-hydroxymethylfurfural (5-HMF) in the overall estimation of reducing sugars (glucose, xylose and arabinose) by DNS assay. In addition to this, reducing sugars estimation in the presence of furans were also investigated, it reveals that reducing sugars estimation was found to be 68% higher than actual sugars. Therefore, current findings strongly indicate that the employment of DNS assay for quantifying the reducing sugars in the presence of furans is not appropriate.

Topics: Aldehydes; Artifacts; Calibration; Chromatography, High Pressure Liquid; Colorimetry; Furaldehyde; Lignin; Reducing Agents; Salicylates; Spectrophotometry; Sugars

The use of saliva for diagnose and surveillance of systemic illnesses, and general health has been arousing great interest worldwide, emerging as a highly desirable goal in healthcare. The collection is non-invasive, stress-free, inexpensive, and simple representing a major asset. Glucose, calcium, and magnesium concentration are three major parameters evaluated in clinical context due to their essential role in a wide range of biochemical reactions, and consequently many health disorders. In this work, a spectrophotometric sequential injection method is described for the fast screening of glucose, calcium, and magnesium in saliva samples. The glucose determination reaction involves the oxidation of the aldehyde functional group present in glucose with simultaneous reduction of 3,5-dinitrosalicylic acid (DNS) to 3-amino, 5-nitrosalicylic acid under alkaline conditions, followed by the development of colour. The determination of both metals is based on their reaction with cresolphtalein complexone (CPC), and the interference of calcium in the magnesium determination minimized by ethylene glycol-bis[β-aminoethyl ether]-N,N,N',N'-tetraacetic acid (EGTA). The developed multi-parametric method enabled dynamic ranges of 50 - 300 mg/dL for glucose, 0.1 - 2 mg/dL for calcium, and 0.1 - 0.5 mg/dL for magnesium. Determination rates of 28, 60, 52 h

Topics: Calcium; Colorimetry; Egtazic Acid; Glucose; Magnesium; Salicylates; Saliva

Use of the 3,5-dinitrosalicylic acid reagent allows the simple and rapid quantification of reducing sugars. The method can be used for analysis of biological samples or in the characterization of enzyme reactions. Presented here is an application of the method in measuring the kinetics of a glycoside hydrolase reaction, including the optimization of the DNSA reagent, and the production of a standard curve of absorbance and sugar concentration.

Topics: Enzyme Assays; Glycoside Hydrolases; Kinetics; Salicylates

In this work we analyzed the vibrational spectra of 3,5-dinitrosalicylic acid (3,5DNSA) molecule. The total energy of eight possible conformers can be calculated by Density Functional Theory with 6-31G(d,p) as basis set to find the most stable conformer. Computational result identify the most stable conformer of 3,5DNSA is C6. The assignments of the vibrational spectra have been carried out by computing Total Energy Distribution (TED). The molecular geometry, second order perturbation energies and Electron Density (ED) transfer from filled lone pairs of Lewis base to unfilled Lewis acid sites for 3,5-DNSA molecular analyzed on the basis of Natural Bond Orbital (NBO) analysis. The formation of inter and intramolecular hydrogen bonding between OH and COOH group gave the evidence for the formation of dimer formation for 3,5-DNSA molecule. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) complements with the experimental findings. The simulated spectra satisfactorily coincides with the experimental spectra.

Topics: Electrons; Hydrogen Bonding; Models, Molecular; Molecular Conformation; Quantum Theory; Salicylates; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Static Electricity; Thermodynamics; Vibration

Organic crystal of 3,5-dinitrosalicylic acid monohydrate has been grown by slow evaporation method at room temperature, using water as solvent. Quantum chemical calculations of energies, geometric structure and vibrational analysis of the title compound are carried out by DFT method with 6-31+G (d,p) basis set. Both the experimental and theoretical spectra confirm the presence of functional groups. Electric dipole moment, polarizability and the first order hyperpolarizability values have been computed theoretically. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the gauge independent atomic orbital (GIAO) method and compared with the experimental results. The calculated HOMO-LUMO energies confirm the charge transfer within the molecule. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound are determined.

Topics: Carbon-13 Magnetic Resonance Spectroscopy; Crystallization; Electrons; Hydrogen Bonding; Models, Molecular; Molecular Conformation; Nonlinear Dynamics; Optical Phenomena; Proton Magnetic Resonance Spectroscopy; Salicylates; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Spectroscopy, Near-Infrared; Static Electricity; Thermodynamics; Vibration; X-Ray Diffraction

About 80% of the Australian population consumes breakfast cereal (BC) at least five days a week. With high prevalence rates of obesity and other diet-related diseases, improved methods for monitoring sugar levels in breakfast cereals would be useful in nutrition research. The heterogeneity of the complex matrix of BCs can make carbohydrate analysis challenging or necessitate tedious sample preparation leading to potential sugar loss or starch degradation into sugars. A recently established, simple and robust free solution capillary electrophoresis (CE) method was used in a new application to 13 BCs (in Australia) and compared with several established methods for quantification of carbohydrates. Carbohydrates identified in BCs by CE included sucrose, maltose, glucose and fructose. The CE method is simple requiring no sample preparation or derivatization and carbohydrates are detected by direct UV detection. CE was shown to be a more robust and accurate method for measuring carbohydrates than Fehling method, DNS (3,5-dinitrosalicylic acid) assay and HPLC (high performance liquid chromatography).

Topics: Australia; Breakfast; Carbohydrates; Chromatography, High Pressure Liquid; Edible Grain; Electrophoresis, Capillary; Humans; Salicylates

Cellulase and xylanase are main hydrolysis enzymes for the degradation of cellulosic and hemicellulosic biomass, respectively. In this study, our aim was to develop and test the efficacy of a rapid, high-throughput method to screen hydrolytic-enzyme-producing microbes. To accomplish this, we modified the 3,5-dinitrosalicylic acid (DNS) method for microwell plate-based screening. Targeted microbial samples were initially cultured on agar plates with both cellulose and xylan as substrates. Then, isolated colonies were subcultured in broth media containing yeast extract and either cellulose or xylan. The supernatants of the culture broth were tested with our modified DNS screening method in a 96-microwell plate, with a 200 μl total reaction volume. In addition, the stability and reliability of glucose and xylose standards, which were used to determine the enzymatic activity, were studied at 100°C for different time intervals in a dry oven. It was concluded that the minimum incubation time required for stable color development of the standard solution is 20 min. With this technique, we successfully screened 21 and 31 cellulase- and xylanase-producing strains, respectively, in a single experimental trial. Among the identified strains, 19 showed both cellulose and xylan hydrolyzing activities. These microbes can be applied to bioethanol production from cellulosic and hemicellulosic biomass.

Topics: Bacteria; Cellulase; Colorimetry; Endo-1,4-beta Xylanases; Enzyme Assays; Fungi; Salicylates

Many Gram-negative bacteria deliver their virulence factors into host cells through a secretion system. Those factors, called effector proteins, are involved in the pathogenicity in host cells by interfering with various cellular events. The phytopathogen Xanthomonas oryzae pv. oryzae uses a type III secretion system to inject its effectors, but the functional roles of these proteins remain largely uncharacterized. Here, we determined a crystal structure of XOO4466, an effector from X. oryzae pv. oryzae, and performed a functional analysis. We determined that XOO4466 is similar in sequence to Xanthomonas outer protein Q, a putative nucleoside hydrolase (NH). The overall structure of XOO4466 is homologous to that of NHs, including a metal-binding site, but differs in its oligomeric state and active site topology. Further analysis indicated that antiparallel β-strands commonly found in NHs adjacent to the active site loop are replaced in XOO4466 with a short loop, causing the active site loop to adopt a conformation distinct from that of NHs. Thus, the catalytic residues emanating from the respective active site loop of NHs are absent in the putative active site of XOO4466. Consistent with these structural features, a functional assay indicated that XOO4466 does not exhibit NH activity and possibly catalyzes yet unknown reactions.

Topics: Amino Acid Sequence; Bacterial Proteins; Calcium; Catalytic Domain; Crystallography, X-Ray; Models, Molecular; Molecular Sequence Data; N-Glycosyl Hydrolases; Protein Structure, Quaternary; Protein Structure, Secondary; Salicylates; Xanthomonas

A comparative study was made between two carbohydrate reducing value methods, a relatively old, highly alkaline, 3,5-dinitrosalicylic acid (DNSA) method and a relatively newer, low alkaline (pH 10.5), copper bicinchoninate (CuBic) method. Reducing values for a series of equimolar amounts of maltose-maltohexaose, isomaltose-isomaltohexaose, and cellobiose-cellohexaose were compared by the two methods. The DNSA method gave over-oxidation for equimolar amounts of all three of the oligosaccharide series. The amount of oxidation increased as the sizes of the oligosaccharides increased, giving inflated, inaccurate reducing values. The CuBic method gave constant reducing values, for equimolar amounts of the oligosaccharides, indicating that there was no over-oxidation, as the sizes of the oligosaccharides were increased. The two methods were used to determine the number average molecular weights (MWn) for six polysaccharides. The DNSA method was not able to determine the MWn for any of the polysaccharides tested due to the low sensitivity of the method, compared with the CuBic method that did not give over-oxidation and gave reasonable MWn values for all six of the polysaccharides tested.

Topics: Animals; Copper; Molecular Weight; Oxidation-Reduction; Quinolines; Rabbits; Reproducibility of Results; Salicylates

A charge transfer complex of o-phenylenediamine (OPD) as donor with 3,5-dinitrosalicylic acid (DNSH) as acceptor, was synthesized and characterized by FTIR, (1)H NMR, (13)C NMR, mass spectroscopy, elemental analysis and X-ray crystallography. The structural investigations exhibit that the cation and anion are joined together by strong N(+)H⋯O(-) type hydrogen bonds and stoichiometry of CT complex was found to be 1:1. The CT (charge transfer) complex shows remarkable interaction with Calf thymus DNA, and the CT complex was also screened for its microbial activity such as antimicrobial and antifungal activities. A molecular frame work through H-bonding interactions via n→π(*) transitions between neighboring moieties is found which is responsible for high melting point of resulting CT complex. This has been attributed to the formation of 1:1 CT complex.

Topics: Animals; Anti-Infective Agents; Bacteria; Bacterial Infections; Cattle; Crystallography, X-Ray; DNA; Fungi; Humans; Magnetic Resonance Spectroscopy; Models, Molecular; Mycoses; Phenylenediamines; Salicylates; Spectroscopy, Fourier Transform Infrared

This study evaluated the interference of the amino acids tryptophan, cysteine, histidine, tyrosine, hydroxyproline, leucine, proline, serine, glycine, valine, glutamic acid, phenylalanine, and methionine on the measurement of reducing sugars using a phenol-free 3,5-dinitrosalicylic acid (DNS) reagent. It was found that in reaction mixtures containing 20mM of either tryptophan, cysteine, histidine, tyrosine, or hydroxyproline the measurement of 3.7 mM glucose was overestimated by 76%, 50%, 35%, 18%, and 10%, respectively. The amino acids valine, glutamic acid, and phenylalanine did not affect the DNS reaction, while methionine decreased the color development by 5%. The measurement of glucose, xylose, arabinose, and cellobiose at the 3.7-12.4 mM range in the presence of 20 mM cysteine resulted in an overestimated concentration of 34.8-50%. Enzymatic assays for measuring xylanolytic and filter paper activity (FPAse) were conducted in the presence of 20-60 mM cysteine, and compared to cysteine-free assays. In the presence of cysteine, the measured xylanase activity increased threefold and the FPAse activity increased twofold due to the overestimation of the reducing sugar concentrations in the assays. The interference from cysteine was reduced to a maximum of 8.6% when a DNS reagent containing phenol was used.

Topics: Amino Acids; Artifacts; Carbohydrates; Colorimetry; Enzyme Assays; Glycoside Hydrolases; Reducing Agents; Salicylates

The 1:1 proton-transfer compound of the potent substituted amphetamine hallucinogen (R)-2-amino-1-(8-bromobenzo[1,2-b;5,4-b']difuran-4-yl)propane (common trivial name 'bromodragonfly') with 3,5-dinitrosalicylic acid, namely 1-(8-bromobenzo[1,2-b;5,4-b']difuran-4-yl)propan-2-aminium 2-carboxy-4,6-dinitrophenolate, C(13)H(13)BrNO(2)(+).C(7)H(3)N(2)O(7)(-), forms hydrogen-bonded cation-anion chain substructures comprising undulating head-to-tail anion chains formed through C(8) carboxyl-nitro O-H...O associations and incorporating the aminium groups of the cations. The intrachain cation-anion hydrogen-bonding associations feature proximal cyclic R(3)(3)(8) interactions involving both an N(+)-H...O(phenolate) and the carboxyl-nitro O-H...O associations and aromatic pi-pi ring interactions [minimum ring centroid separation = 3.566 (2) A]. A lateral hydrogen-bonding interaction between the third aminium H atom and a carboxyl O-atom acceptor links the chain substructures, giving a two-dimensional sheet structure. This determination represents the first of any form of this compound and is in the (R) absolute configuration. The atypical crystal stability is attributed both to the hydrogen-bonded chain substructures provided by the anions, which accommodate the aminium proton-donor groups of the cations and give crosslinking, and to the presence of the cation-anion aromatic ring pi-pi interactions.

Topics: Crystallography, X-Ray; Furans; Hallucinogens; Hydrogen Bonding; Models, Molecular; Molecular Structure; Propane; Protons; Salicylates; Stereoisomerism

To implement a protein engineering strategy for the improvement of enzyme performance on biomass, a straightforward, robust high-throughput method was devised and tested with recombinant GH11 xylanase as acting on wheat straw. The method requires automated liquid handling equipment, but avoids the need for specialized milling and powder weighing devices and the use of labour intensive steps such as manual cutting of pipette tips. After expression in Escherichia coli cells grown in microtiter plates, recombinant xylanase was released into the culture medium and used directly for biomass hydrolysis. Reactions were monitored using a micro-3,5-dinitrosalicylic acid assay. The cumulative error of the method was less than 15%. To validate the method, randomly generated xylanase mutants were analyzed. This allowed the detection of one mutant, which produced a 74% increase in hydrolysis compared to the parental enzyme. Closer analysis revealed that this increase in activity was correlated with a twofold increase in xylanase expression.

Topics: Bacillus; Base Sequence; Biological Assay; Biomass; Electrophoresis, Polyacrylamide Gel; Endo-1,4-beta Xylanases; Glycoside Hydrolases; High-Throughput Screening Assays; Hydrolysis; Molecular Sequence Data; Nucleic Acid Conformation; Polymerase Chain Reaction; RNA, Messenger; Salicylates; Triticum

It was found, that alkali metal-europium dinitrosalicylates of composition M(3)Eu(3,5-NO(2)-Sal)(3).nH(2)O (M=Li, Na, K, Cs) are intense red luminophores with wide excitation band. Using methods of optical spectroscopy we studied the influence of nitrogroups and alkali metal counterions on Eu(3+) luminescence efficiency and on processes of excitation energy transfer to Eu(3+) ion in compounds synthesized. The Eu(3+) luminescence and Eu(3+) luminescence excitation spectra, as well as vibrational IR and Raman spectra were investigated. Details of the structure of compounds were discussed. The network of hydrogen bonds in lanthanide dinitrosalicylates is weakening at introduction of large alkali metal ions in compounds and at the increase of the temperature. As a consequence, the long-wavelength shift of the intraligand charge transfer (ILCT) band in Eu(3+) excitation spectra arises at inclusion of Cs(+) cations instead of Li(+) in the crystal lattice of europium dinitrosalicylates and at heating of these compounds. To obtain the energy of the lowest excited triplet state the phosphorescence spectra of alkali metal-gadolinium compounds M(3)Gd(3,5-NO(2)-Sal)(3).nH(2)O, of alkali metal dinitrosalicylate and salicylate salts were measured with time delay. Change of the energies of ligand electronic states and ligand-metal charge transfer state (LM CTS) can give a two-three orders of magnitude enhancement of the Eu(3+) luminescence efficiency in dinitrosalicylates in comparison with salicylates and ten-fold enhancement at the substitution of Li(+) and Na(+) for Cs(+) in dinitrosalicylates.

Topics: Color; Europium; Luminescence; Luminescent Measurements; Salicylates; Spectrum Analysis

Nanometer size titanium dioxide modified with 3,5-dinitrosalicylic acid (3,5-DA) was prepared using chemical adsorption method. The influences of surface modification on the adsorption of p-nitrophenol (PNP) and the dispersion in solvent such as water, benzene and ethanol were studied. The 3,5-dinitrosalicylic acid is bonded to the surface hydroxyl from TiO2 nanoparticles, results in the formation of a stable, six-ring complex which color is buff. The 3, 5-DA-modified TiO2 nanoparticles have good dispersive capacity in water, benzene and ethanol. Under the optimum conditions such as pH value 3, adsorption time 10 min, the adsorption ratio of PNP by TiO2 is improved from 43% to 99.9% through surface modification. A new method could be used to remove directly 3 approximately 10mg/L PNP, and the residual concentrations is below the integrated wastewater discharge standard (GB 8978-1996).

Topics: Adsorption; Metal Nanoparticles; Nitrophenols; Salicylates; Titanium; Waste Disposal, Fluid

An effective and novel approach to obtaining electrorheological particles with high performance through the formation of host-guest complexes has been achieved. The significant preponderance of the host-guest complex formation is that the host structure can be controlled easily by adding different guests. Based on this point, six supramolecular complexes of beta-cyclodextrin cross-linking polymer with salicylic acid (beta-CDP-1), 5-chlorosalicylic acid (beta-CDP-2), 3,5-dichlorosalicylic acid (beta-CDP-3), 5-nitrosalicylic acid (beta-CDP-4), 3,5-dinitrosalicylic acid (beta-CDP-5), or 3-hydroxy-2-naphthoic acid (beta-CDP-6) particles were synthesized. The electrorheological yield stresses of the suspensions of these particles in silicone oil have been investigated under DC electric fields. It was found that the yield stress of the typical beta-CDP-1 ER fluid was 5.6 kPa in 4 kV/mm, which is much higher than that of pure beta-cyclodextrin polymer (beta-CDP), that of pure salicylic acid as well as that of the mixture of the host with the guest. It is clearly indicated that the formation of supramolecular complexes between beta-CDP and salicylic acid can enhance the ER properties of the host. The similar results for other supramolecular complexes with different guests have also been obtained under the same DC electric fields. The yield stress of supramolecular complexes is strongly affected by the structure of guests. Among the six investigated guests, 3-hydroxy-2-naphthoic acid gave the highest ER property having a yield stress of 9.8 kPa under 4 kV/mm DC while cross-linked with beta-CDP to form beta-CDP-6. The yield stress of beta-CDP-6 was significantly increased by 72% in comparison with that of the pure beta-CDP. However, the yield stress of beta-CDP-1-5 slightly increased by 34-41% as compared with that of the pure beta-CDP. The achieved results indicate that the ER effect of host-guest complexes can be greatly affected by the changes of the tremendous guest structure, whereas the slight guest structural transposition, such as altering different groups of a guest, can only obtain the adjacent electrorheological behavior. The dielectric properties of these host-guest complexes also proved that the ER effect can be affected by the properties of guest.

Topics: beta-Cyclodextrins; Chlorobenzoates; Electrophoresis; Molecular Structure; Naphthols; Particle Size; Polymers; Rheology; Salicylates; Salicylic Acid; Silicone Oils; Static Electricity

Two suggestions can be found in the literature to improve the reproducibility of the Mandels' filter paper assay: add supplemental cellobiase and increase the boiling time for color development. Here we provide data that strongly supports adding supplemental cellobiase. Adding supplemental cellobiase increased assay response by 56%. Cellulases from different sources have different cellobiase activities, which would cause significant variation in the assay response. There is no need for additional boiling time-5 minutes is sufficient. For maximum reproducibility, it is essential that the water bath vigorously boil so that temperature excursions are minimized.

Topics: beta-Glucosidase; Biosensing Techniques; Cellulase; Colorimetry; Enzyme Activation; Filtration; Hot Temperature; Quality Control; Salicylates; Sensitivity and Specificity; Substrate Specificity

Inspired by the occurrence and function of phenazines in natural products, new glycosylated analogs were designed and synthesized. DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors were used in an efficient and easily-handled glycosylation protocol compatible with combinatorial chemistry. Benzoylated D-glucose, D-galactose and L-quinovose DISAL glycosyl donors were synthesized in high yields and used under mild conditions to glycosylate methyl saphenate and 2-hydroxyphenazine. The glycosides were screened for biological activity and one compound showed inhibitory activity towards topoisomerase II.

Topics: Chemistry, Organic; Chromatography, High Pressure Liquid; Glycosylation; Models, Chemical; Phenazines; Salicylates; Streptomyces

Topics: Air Pollutants, Occupational; Photometry; Salicylates

The activity of yeast trehalase when assayed at pH 7 in a crude extract was found to increase 2- to 3-fold upon incubation with 0.1% (v/v) polyethyleneimine or other polycations such as polylysine (0.075-mMol) and calf thymus histones (0.08 mMol). Incubation with 3 mM-Mn2+ and 5 mM-Ca2+ also led to 3- and 1.6-fold increases in trehalase activity, respectively. The activities of 11 other enzymes assayed in the crude yeast extract did not increase after addition of polyethylene imine. At concentrations of polyethyleneimine that maximally stimulated trehalase activity, 97% of the total RNA present in the crude extract, 40% of total protein, and 60% of the polyphosphate (assayed as inorganic phosphate liberated during 7 min incubation at 95 degrees C and pH O) were found to be precipitated. A similar finding was made with trehalase-stimulating concentrations of Mn2+. Activation of trehalase by polyethylene imine rendered this enzyme susceptible to inhibition by a preparation of total yeast RNA, inorganic polyphosphates, and related polyanions. We present further evidence that the removal of a distinct RNA and/or polyphosphate is the basic principle of polyethyleneimine-induced activation of trehalase. A more pronounced stimulation of trehalase activity (4-fold) could be obtained by enzymatic phosphorylation with ATP in the presence of cyclic AMP and Mg2+ as described by van Solingen and van der Plaat (1975) [9].(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Glucose Oxidase; Hydrogen-Ion Concentration; Metals; Phosphates; Polyphosphates; RNA, Fungal; Saccharomyces cerevisiae; Salicylates; Time Factors; Trehalase

A procedure is described for monitoring the temperature in the reaction cuvettes of analytical systems that use photometers. The method employs the temperature-dependent change in absorbance of solutions of either 3,5-dinitrosalicylic acid or cresol red. The procedure is simple to perform and is especially useful in monitoring the temperature in instruments such as centrifugal analysers where the reaction cuvette is inaccessible. In some of the instruments studied, methodological changes were required to ensure that reactions were carried out at the selected temperature.

Topics: Hydrogen-Ion Concentration; Phenolsulfonphthalein; Salicylates; Spectrophotometry; Temperature

Topics: Adult; Dermatitis, Contact; Dermatitis, Occupational; Female; Humans; Nitrazepam; Pigmentation Disorders; Salicylates; Skin Pigmentation