FLUORESCENCE OF AZOTOBACTER: I. A COMPARISON OF THE FLUORESCENT PIGMENTS WITH RIBOFLAVIN

1959 ◽  
Vol 5 (3) ◽  
pp. 299-304 ◽  
Author(s):  
D. B. Johnstone ◽  
M. Pfeffer ◽  
G. C. Blanchard
Keyword(s):  
Acid Solution ◽  
Organic Solvents ◽  
Alkaline Solution ◽  
Paper Electrophoresis ◽  
Water Soluble ◽  
Absorption Peak ◽  
Partial Purification ◽  
Acid Electrolyte ◽  
Riboflavin Production ◽  
Marked Fluorescence

The fluorescent pigments elaborated in cultures of certain species of Azotobacter were compared with riboflavin produced by the same cultures. No correlation between the amounts of fluorescence and riboflavin was observed. Iron appears to inhibit the synthesis of the fluorescent pigments but stimulates riboflavin production. The fluorescent pigments obtained from Azotobacter were water-soluble, thermostable, insoluble in water-free organic solvents, and each exhibited a single absorption peak in the region of 370–380 mμ in slightly acid solution shifting to 400–420 in alkaline solution. Partial purification has been achieved by continuous paper electrophoresis with an acid electrolyte. These studies appear to indicate that the marked fluorescence observed in certain Azotobacter cultures cannot be attributed to riboflavin.

Synthesis and Photoproperties of a Substituted Zinc(II) Phthalocyanine-N-(2-hydroxypropyl)methacrylamide Copolymer Conjugate

1993 ◽  
Vol 58 (10) ◽  
pp. 2321-2336 ◽  
Author(s):  
Zhong-wei Gu ◽  
John D. Spikes ◽  
Pavla Kopečková ◽  
Jindřich Kopeček
Keyword(s):  
Organic Solvents ◽  
Water Soluble ◽  
Lower Probability ◽  
Hpma Copolymer ◽  
Polymeric Derivative ◽  
Oxygen Generation ◽  
Hpma Copolymers ◽  
Hydroxypropyl Methacrylamide ◽  
Polymeric Carriers ◽  
Thiol Proteinases

In cancer photodynamic therapy (PDT), improved efficiency of photosensitizer delivery to tumors may be obtained by binding them to targetable water soluble polymeric carriers. However, attachment of photosensitizers to Macromolecular carriers may alter their spectral and photosensitizing properties. In this study, a new monosubstituted phthalocyanine derivative, N-glycyl zinc(II) 4,9,16,23-tetraaminophthalocyanine (G-TAPC-Zn) was synthesized by the reaction of zinc(II) 4,9,16,23-tetraaminophthalocyanine (TAPC-Zn) with N-tert-butoxycarbonyl-glycine N'-hydroxybenzotriazole ester followed by deprotection of the tert-butoxycarbonyl (BOC) group. G-TAPC-Zn contains an aliphatic amino group suitable for attachment to water soluble polymeric carriers. By aminolysis of a polymeric precursor, an N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer containing oligopeptide (GFLG) side-chains terminated in p-nitrophenyl ester groups, with G-TAPC-Zn a polymeric derivative of the latter (P-GFLGG-TAPC-Zn) was synthesized. Spectral data indicated that in aqueous solutions P-GFLGG-TAPC-Zn formed aggregates. The degree of aggregation decreased with increasing concentration of detergents or organic solvents in buffer solutions. Consequently, the release of the drug from carrier catalyzed by thiol proteinases, papain or cathepsin B, took place only in the presence of detergents or organic solvents, i.e., under conditions with a lower probability of aggregate formation. Binding of G-TAPC-Zn to HPMA copolymers decreased the quantum yield of singlet oxygen generation from 0.24 to 0.063 and significantly increased its resistance to photobleaching.

VIII.—The Stability of Suspensions. I. The Rate of Sedimentation of Kaolin Suspensions by Salts at Varying Hydrogen Ion Concentrations

1926 ◽  
Vol 45 (1) ◽  
pp. 59-70 ◽  
Author(s):  
William Ogilvy Kermack ◽  
William Turner Horace Williamson
Keyword(s):  
Sodium Chloride ◽  
Acid Solution ◽  
Alkaline Solution ◽  
Calcium Sulphate ◽  
Sodium Sulphate ◽  
Aluminium Chloride ◽  
Monocalcium Phosphate ◽  
Sodium Hydrogen Phosphate ◽  
Rate Of Sedimentation ◽  
The Stability

Summary1. The rates of sedimentation of a kaolin suspension in presence of varying concentrations of a salt (sodium chloride, potassium chloride, sodium sulphate, di-sodium hydrogen phosphate, sodium citrate, calcium chloride, calcium sulphate, monocalcium phosphate, “superphosphate”, aluminium chloride, ferric chloride or lanthanum chloride) have been compared at various pH values. Abnormal results are obtained with sodium chloride, monocalcium phosphate, aluminium, ferric and lanthanum chlorides.2. Sodium chloride increases the rate of sedimentation in alkaline solution, but actually inhibits it in acid solution.3. In concentrations of monocalcium phosphate above 0·06 per cent, abnormal sedimentation in alkaline solution takes place, with the result that it is much more complete than at the corresponding concentrations in acid solution.4. In acid solution the tervalent ions, aluminium, ferric and lanthanum have little effect, but a zone of very marked flocculation occurs at pH 7–8. This zone separates a region within which the unsedimented particles are negatively charged from a region within which they are positively charged.

scholarly journals Creep Strain and Permeability Evolution in Cracked Granite Subjected to Triaxial Stress and Reactive Flow

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Fan Zhang ◽  
Jianjian Zhao ◽  
Dawei Hu ◽  
Qian Sheng ◽  
Jianfu Shao
Keyword(s):  
Acid Solution ◽  
Strain Rate ◽  
Creep Strain ◽  
Alkaline Solution ◽  
Confining Pressure ◽  
Creep Strain Rate ◽  
Reactive Flow ◽  
Secondary Creep ◽  
Creep Tests ◽  
Creep Stage

Fluid flow and fluid-rock interaction mainly take place in fracture network, consequently resulting in deformation and permeability variation of rock and deterioration of the wellbore performance. Mechanical-reactive flow coupling creep tests are performed on cracked granite under various confining pressures and acid and alkaline solution flows. The testing results show that the confining pressure and solution pH significantly influence the creep deformation, creep strain rate, and permeability. A primary creep stage and secondary creep stage are observed in all creep tests in this study; notably, the sample under a confining pressure of 10 MPa and acid solution injection undergoes creep failure for over 2700 hours. The acid solution has a more obvious influence on the creep behavior than that of the alkaline solution. With an increase in confining pressure, the total creep strain and creep strain rate in the samples gradually decrease during the injection of either solution. The permeability of the samples injected with either solution gradually deceases during the testing process, and this deceasing rate increases with the confining pressure. The scanning electron microscopy observations on the crack surfaces after the creep tests show that the surfaces of the fractures injected with the acid solution are smooth due to the dissolution of the matrix, while those injected with the alkaline solution include voids due to the dissolution of quartz. These experimental results could improve the understanding of the long-term transport and mechanical behaviors of wellbore.

scholarly journals The UV-Vis Study On Anthocyanin Pigments Activities Extracted From Gayo Arabika Coffee Husks

Elkawnie ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 147
Author(s):  
Hasby Hasby ◽  
Nurhafidhah Nurhafidhah ◽  
Said Ali Akbar
Keyword(s):  
Hydrochloric Acid ◽  
Acid Solution ◽  
Absorption Peak ◽  
Solution Temperature ◽  
Arabica Coffee ◽  
Coffee Husk ◽  
Long Term Stability ◽  
Acidic Conditions ◽  
Anthocyanin Pigments

The anthocyanin activity of Gayo Arabica coffee husk in variations in acid solution, temperature, and pH has been assessed through UV-Vis studies. It is important to optimize these factors to increase the long-term stability of anthocyanins for use in various fields. Gayo Arabica coffee husks was extracted through maceration method with methanol. This process obtained a coffee husks extract of 1.176 mg/μL. The UV-Vis spectrum of the extract displayed the major absorption peak at λmax= 529 nm in hydrochloric acid (HCl), this assigned by the electronic transition from flavylium as the particular characteristic of anthocyanin compounds. The anthocyanin from the extract was stable at temperatures of 35oC and 50oC, to have a major absorption peak at λmax= 529 nm. Therefore, it could probably be said that the lower the temperature, the higher the absorbance value of anthocyanin. Then, husks extract was getting red at pH 1 and 3; almost colorless at pH 5, 8 and 10; and yellow at pH 12. The more acidic conditions causes more anthocyanin pigments to be observed in the form of flavylium or oxonium cations color. Finally, Gayo Arabica coffee husks extract can absorb both ultraviolet (UV) and visible light (visible).

Impurities in Commercial Saccharin. I. Impurities Soluble in Organic Solvents

1976 ◽  
Vol 59 (5) ◽  
pp. 1051-1058 ◽  
Author(s):  
Bozidar Stavrić ◽  
Raymond Klassen ◽  
W Arnold
Keyword(s):  
Organic Solvents ◽  
Water Solution ◽  
Water Soluble ◽  
Chromatographic Column ◽  
Gas Liquid Chromatography ◽  
Sodium Saccharin ◽  
Chemical Purity ◽  
Liquid Chromatographic ◽  
Chloroform Methanol ◽  
Sodium Form

Abstract Thirteen saccharin samples used for carcinogenicity tests in animals in various laboratories were analyzed for their chemical purity. Although most of the impurities were water-soluble, some were mainly soluble in organic solvents. These impurities were extracted with chloroform-methanol from a water solution of sodium saccharin. Samples obtained as acid-saccharin were converted to the sodium form before extraction. The major impurity in commercial saccharin, o-toluenesulfonamide, was also soluble in this system. Impurities were separated by gas-liquid chromatography of the underivatized, concentrated extract. Eleven major, well separated peaks were collected from the gas chromatographic column and identified by mass spectroscopy. Some of the peaks were compared with known standards. Qualitative and quantitative differences in impurities were observed among different saccharin samples. The identified impurities (in order of appearance from the gas-liquid chromatographic column) were as follows: o-toluenesulfonamide; p-toluenesufonamide; 1,2-benzisothiazole 1,1-dioxide; 1,2-benzisothiazoline 1,1-dioxide; diphenylsulfone; o,o′-ditolylsulfone; o,m′-ditolylsulfone, o,p′-ditolylsulfone; m,p′-ditolylsulfone; p,p′-ditolylsulfone, and tetracosane.

scholarly journals Photolysis of carboxymethylflavin in aqueous and organic solvent: a kinetic study

RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 26559-26571 ◽  
Author(s):  
Iqbal Ahmad ◽  
Tania Mirza ◽  
Syed Ghulam Musharraf ◽  
Zubair Anwar ◽  
Muhammad Ali Sheraz ◽  
...  
Keyword(s):  
Acid Solution ◽  
Organic Solvent ◽  
Kinetic Study ◽  
Alkaline Solution ◽  
Ring Cleavage ◽  
Side Chain ◽  
Keto Acid ◽  
Side Chain Cleavage ◽  
Chain Cleavage

Carboxymethylflavin (CMF) undergoes photolysis in acid solution to form lumichrome (LC) and in alkaline solution, LC and lumiflavin (LF) by side-chain cleavage and β-keto acid and a dioxoquinoxalaine (DQ) compound by isoalloxazine ring cleavage.

Isolation of the virus inhibitor from the root extract of Boerhaavia diffusa inducing systemic resistance in plants

1979 ◽  
Vol 57 (11) ◽  
pp. 1214-1217 ◽  
Author(s):  
H. N. Verma ◽  
L. P. Awasthi ◽  
K. C. Saxena
Keyword(s):  
Molecular Weight ◽  
Organic Solvents ◽  
Preliminary Analysis ◽  
Antiviral Agent ◽  
Systemic Resistance ◽  
Partial Purification ◽  
Root Extract ◽  
Virus Inhibitor ◽  
Boerhaavia Diffusa

An antiviral agent, active against spherical and tubular viruses in hypersensitive and systemic hosts, has been isolated from the roots of Boerhaavia diffusa. Partial purification of inhibitor by organic solvents, Sephadex gel, and protein precipitants has been achieved. Preliminary analysis indicates that the inhibitor may be a glycoprotein with a molecular weight of 16 000–20 000 daltons.

ACCESSORY FOOD SUBSTANCES FOR OSMOPHILIC YEASTS: I. A BIOACTIVATOR IN HONEY STIMULATING FERMENTATION

1931 ◽  
Vol 5 (5) ◽  
pp. 529-538 ◽  
Author(s):  
A. G. Lochhead ◽  
Leone Farrell
Keyword(s):  
Acid Solution ◽  
Alkaline Solution ◽  
Prolonged Exposure ◽  
Selective Adsorption ◽  
Active Principle ◽  
Dry Heat ◽  
Synthetic Media ◽  
Stimulation Of

Honey was found to contain an active principle which stimulated fermentation by certain osmophilic yeasts of the genus Zygosaccharomyces in synthetic media. The substance is dialyzable, insoluble in ether and acetone, not precipitated by 85% alcohol, resistant to heating in acid solution and non-volatile. The activating effect of honey is impaired by heating in alkaline solution and by prolonged exposure to moderate dry heat. The active principle may be separated into two fractions by selective adsorption by charcoal. The adsorbed fraction, which may be recovered by elution with alcohol, and the unadsorbed fraction are relatively inert alone, the presence of both being necessary for the active stimulation of fermentation.

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