Thymus Nucleic Acid Research Articles

Synthesis of novel fluorescent probe Tb(III)-7-carboxymethoxy-4-methylcoumarin complex for sensing of DNA

New fluorescent probe Tb(III) (7-carboxymethoxy-4-methylcoumarin)2(SCN) (C2H5OH)(H2O) was synthesized and characterized by spectroscopy and thermal analysis. The absorption and fluorescence spectra of 7-carboxymethoxy-4-methylcoumarin (CMMC) and Tb(III)–CMMC complex have been measured in different solvents. The interactions of Tb(III)–CMMC complex with calf thymus nucleic acid (CT-DNA) have been investigated using steady state fluorescence measurements. The changes in the fluorescence intensity have been used for the quantitative determination of DNA with LOD of 3.45ng in methanol–water (9:1,v/v). The association constants of DNA with Tb(III)–CMMC complex was found to be 2.62×1010M−1.

Resonance Light Scattering Method for Study on the Interaction Between Fluorinated Surfactant Potassium Perfluorooctanesulfonate and DNA

Resonance light-scattering (RLS) characteristics of the interactions between fluorinated surfactant potassium perfluorooctanesulfonate (PFOS) with calf thymus nucleic acid (ct DNA) were studied. After DNA was added, aggregation of PFOS on the molecular surface of DNA occurred in the pH 3.5 ∼6.0, which resulted in an enhanced RLS peak at 370 nm. The RLS intensity was found to be proportional to the concentration of DNA. The determination limit was 20.0 μg · L−1. UV-visible (UV-vis) spectra and infrared (IR) spectra both proved the binding changed the confromation of DNA.

Determination of nucleic acid based on increased resonance light-scattering of fluorinated surfactants

Two novel surfactants perfluoroalkanesulfonyl quaternary ammonium iodides (FC134) and potassium perfluorooctanesulfonate (FC95) were successfully used as new probes for detection of DNA by resonance light-scattering (RLS) technique. Resonance light-scattering characteristics of the binding of fluorinated surfactants FC134 and FC95 to calf thymus nucleic acid (ctDNA) were studied. After DNA was added, aggregation of FC134 on the molecular surface of DNA in the pH 3.0–6.0 and aggregation of FC95 on the surface of DNA in the pH 3.5–6.0 occurred, both of which resulted in an enhanced resonance light-scattering peak at 370 nm. The intensity of resonance light-scattering was found to be proportional to the concentration of DNA. The determination limits were 3.5 and 20.0 μg L −1, respectively. UV–vis spectra and IR-spectra both proved the binding of fluorinated surfactants to DNA.

A study of the preparation of thymus nucleic acid according to Gulland et al.

The method of Gulland et al. of preparing DNA has been investigated. It is found that, when using as mild methods of preparation as possible, the output is 5–10% of the DNA in the nucleoprotein used as starting material. The amount of liberated nucleic acid corresponds to the amount of protein which dissociates according to Fleming and Jordan. The prepared DNA contains between 0.1–0.25% of amino acids. A vigorous hydrolysis is necessary to get a positive ninhydrin reaction. All the amino acids of the nucleoprotein are found in the hydrolysate with the exception of proline.

Effect of rate of shear on the reduced viscosities of thymus nucleic acid solutions

Effect of rate of shear on the reduced viscosities of thymus nucleic acid solutions

Electron microscopy of thymonucleic acid

Samples of calf thymus nucleic acid prepared by Mirsky's method have been examined in the electron microscope. Different appearances have been recorded according to the initial state of aggregation of the aqueous systems studied, which was varied from a solution (0.25%) to a gel. When droplets of the solution are dried directly on the grids, the micrographs show that the material splits up in spherical elements, distributed at random, but of even size (diameter circa 160 A). The films formed by spreading the gel onto the grid without support of collodion show a definite structure. The spherical units are organised in fibrils which form a network. The holes in the mesh are of different sizes but are often hexagonal in shape. Amongst the network, streaks of the material, looking like fibres, are frequently observed. They present a banded structure, with a constant spacing at right angles to their axis (circa 800 A), and they blend with the network.

A comparative study of the anomalous viscosity of a high molecular weight polyelectrolyte and thymus nucleic acid

It has been shown that the viscosity of aqueous solutions of the sodium salt of polymethacrylic acid (P.M.A.) of high ( i.e. 2 · 10 6) but not of low ( i.e. 2 · 10 5) molecular weight shows a very pronounced shear-dependence. The viscous anomaly is decreased by (1) reducing the degree of ionisation of the polymer, (2) increasing the ionic strength, (3) addition of urea. From the relationship between viscosity and concentration it is concluded that the anomalous viscosity results from the reversible formation of a network of chains which is progressively broken down by increasing rate of shear. The viscous behaviour of P.M.A. and thymus nucleic acid (T.N.A.) is qualitatively very similar and by analogy it is proposed that the shape of the T.N.A. molecule in solution is determined by the electrostatic repulsion of the phosphate groups. The reduction of this repulsion ( e.g. by adding salt) leads to a coiling of the molecule resulting in decreased interaction and hence a decrease in the shear-dependence ( i.e. a reduction in viscosity at low rates of shear).

Similarities between thymus nucleic acid and a polyelectrolyte

Similarities between thymus nucleic acid and a polyelectrolyte

The Isolation and Identification of Desoxy-5-methylcytidylic Acid from Thymus Nucleic Acid1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Isolation and Identification of Desoxy-5-methylcytidylic Acid from Thymus Nucleic Acid1Waldo E. CohnCite this: J. Am. Chem. Soc. 1951, 73, 4, 1539–1541Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://doi.org/10.1021/ja01148a039RIGHTS & PERMISSIONSArticle Views62Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (330 KB) Get e-Alerts Get e-Alerts

Direct isolation of D-deoxyribose by mercaptanolysis of calf thymus deoxyribonucleic acid.

THE identity of 2-deoxyribose as a carbohydrate constituent of thymus nucleic acid was demonstrated by Levene. Using acidic hydrolysis1 and enzymic methods2, it was possible to prove that 2-deoxyribose was combined with the purine residues in the nucleic acid, though the nature of the sugar combined with the pyrimidine moiety is still uncertain3.

Occurrence of 5-methylcytosine in nucleic acids.

THE presence in a nucleic acid of the pyrimidine 5-methyl-cytosine was first reported in 1925 by Johnson and Coghill1, who claimed its discovery among the hydrolysis products of tuberculinic acid. As their identification, however, was based solely on the optical properties of the crystalline picrate, the correctness of this report has been subject to speculation; yet until the recent application of paper chromatography to nucleic acid analysis, there has been no published attempt to confirm their finding. Recently, using a chromatographic method, Vischer, Zamenhof and Chargaff2 have estimated the purines and pyrimidines in deoxypentose nucleic acid from avian tubercle bacilli, and could find no trace of methyl-cytosine. Hotchkiss3, however, has noted in hydrolysed thymus nucleic acid a small amount of a substance the chromatographic behaviour and ultraviolet absorption spectrum of which are compatible with its being 5-methyl-cytosine.

Crystalline desoxyribonuclease; digestion of thymus nucleic acid; the kinetics of the reaction.

A study was made of the enzymatic properties of crystalline desoxyribonuclease. The general effect of the crystalline enzyme on its specific substrate, thymus nucleic acid, was found to be essentially the same as described by previous workers for the digestive action of crude preparations of the enzyme. The digestive action consists mainly in splitting thymus nucleic acid into fragments approaching the size of tetranucleotides. The digested nucleic acid is diffusible through collodion or cellophane membranes and is non-precipitable with strong acid, alcohol, or proteins. The digestion of thymus nucleic acid by desoxyribonuclease is accompanied by the liberation of one atom equivalent of free acid per four atoms of nucleic acid phosphorus. Crystalline desoxyribonuclease acts very slowly, if at all, in the absence of magnesium (or manganese) ions. The optimal concentration of magnesium ion required increases with the increase in concentration of the substrate but is independent of the enzyme concentration. The optimal pH range for the action of crystalline desoxyribonuclease is 6.0 to 7.0. A study was made of the kinetics of the digestion of thymus nucleic acid as manifested mainly by the gradual formation of acid-soluble split products. At low concentrations of nucleic acid, the process approximates closely a reaction of the first order, the unimolecular constant being independent of the concentration of desoxyribonuclease in the digestion mixture. At relatively higher concentrations of substrate, however, the initial rate of reaction decreases rapidly with the increase in concentration of substrate, and the reaction as a whole is represented by non-symmetric S-shaped curves apparently too complicated for a simple rational interpretation.

Crystalline desoxyribonuclease; isolation and general properties; spectrophotometric method for the measurement of desoxyribonuclease activity.

A crystalline enzyme capable of digesting thymus nucleic acid (desoxyribonucleic acid) has been isolated from fresh beef pancreas. The enzyme called "desoxyribonuclease" is a protein of the albumin type. Its molecular weight is about 60,000 and its isoelectric point is near pH 5.0. It contains about 8 per cent tyrosine and 2 per cent tryptophane. It is readily denatured by heat. The denaturation is reversible if heated in dilute acid at pH about 3.0. The digestion of thymus nucleic acid by crystalline desoxyribonuclease is accompanied by a gradual increase in the specific absorption of ultraviolet light by the acid. The spectrophotometric measurement of the rate of increase in the light absorption can be conveniently used as a general method for estimating desoxyribonuclease activity. Details are given of the method for isolation of crystalline desoxyribonuclease and of the spectrophotometric procedure for the measurement of desoxyribonuclease activity.

The Effect of Yeast Nucleic Acid on the Survival Time of 600 Day Old Albino Mice

The investigation of the effect of nutritional factors on the process of aging has only recently been given attention. In this paper, Dr. Gardner reports on the increase which yeast nucleic acid produces in the life span of 600 day old albino mice, and contrasts his results with those of an earlier investigator who administered both yeast and thymus nucleic acid in far larger amounts to mice from birth. Dr. Gardner discusses three possible explanations for the increase in longevity produced by nucleic acids: maintenance of a high nucleocytoplasmic ratio in the cells, oxidation of ingested nucleic acids in place of cell nucleic acids, and stimulation of leukocytic activity.

Reactions of ragweed-sensitive individuals to skin tests with nucleic acids and related compounds

1. 1. Eleven of thirty ragweed-sensitive patients reacted to test with nucleic acid from yeast, but only three of these reactions were + + or + + +, and none were comparable to the reactions of the same patients to ragweed pollen extract. 2. 2. Four of twelve patients reacted to thymus nucleic acid, and a few patients reacted slightly to guanine hydrochloride, adenine sulfate, histadine monohydrochloride, allantoin, proline, and xanthine. 3. 3. In several cases, the reactions to nucleic acid were also demonstrated by the method of passive transfer. 4. 4. The significance of these reactions was not apparent. 5. 5. None of sixteen normal controls reacted to any of these compounds on direct skin test.

The Antigenic Structure of Hemolytic Streptococci of Lancefield Group A

Summary Electrophoretic examination of the M-substance confirmed the fact that the nucleic acid present was free and that there was very little other contamination of the type-specific protein. Determinations of the mobility of the chemically purified type-specific M-protein at various pHs indicated that its isoelectric point is about pH 5.4. The mobility of the NPA-protein at pH 6.0 and 8.0 has been found to be twice as great as that of the M-protein and permits the recognition of each in mixtures. Nucleic acid was found to be the principal contaminant of NPA preparations. The nucleic acids encountered have high mobilities and the values determined in mixtures of protein and nucleic acid, such as the M-substance and NPA, were similar to those for purified streptotoccal nucleic acids. The data obtained for streptococcal nucleic acid are discussed in relation to the mobilities of yeast and thymus nucleic acid. It was concluded that the streptococcal capsular polysaccharide was not present in any of the streptococcal fractions studied since no component was seen with the mobilities to be expected from a study of the similar vitreous-humor polysaccharide. The mobility of this polysaccharide was high and the same at both pH 6.0 and 8.0. The group-specific polysaccharide, observed in one preparation of other streptococcal fractions, on the basis of this and more extensive observations with the purified polysaccharide, had little or no mobility.

SOME CONSTITUENTS OF ELEMENTARY BODIES OF VACCINIA

Treatment of elementary bodies of vaccinia with dilute solutions of sodium hydroxide resulted in the extraction of certain soluble materials accounting for half of the dry weight of the virus. Elementary bodies contained about 0.4 per cent inorganic phosphorus, practically all of which occurred in the form of a nucleoprotein containing thymus nucleic acid. In addition, a substance was recovered that reacted with S antibodies. From past experience one is led to believe that S antigen, as ordinarily encountered, is a protein which is not in combination with nucleic acid.

Effect of pH on Thickness of Surface Films Made with Insulin and Other Large Molecules

By using suitable adaptations of the methods developed by Langmuir, Schaefer and Blodgett12 films of salmine, insulin, thymus histone, thymus nucleic acid, trypsin, and casein have been built up on chrome plated iron or on stainless steel plates. These plates were first covered with a suitable number of layers of barium stearate by the method of Blodgett.2 They were then immersed in a 10-3 M solution of uranyl acetate at pH 6.0 to condition the barium stearate surface, thus rendering it hydrophilic. Each conditioned plate with an adhering layer of water was then immersed in a 0.1% solution of the substance to be adsorbed and shaken in this solution for the period of time cited. The plate was then removed, washed, and dried in air. The insulin and other surface films described below were thus formed by adsorption of molecules or molecular aggregates directly from solution and not by transfer of films previously formed on the surface of a solution. The thickness of such films has been studied as a function ...

On the Mature Pollen Grains in Angiosperms

1) The mature pollen grains of eighteen angiospermous species were investigated in the living and the fixed state, with special references to FEULIGEN'S nucleal-reaction.2) The “droplets-sheath” has been found around the generative nucleus in nine angiospermous species (Monocotytedonae: six species; Dicotyledonae: three species), while it could not be observed in nine species.3) The quantity of the thymus nucleic acid contained in the vegetative nucleus is of various degrees in the different species, and does not correlate with the degree of transformation of the vegetative nucleus.

THE RING STRUCTURE OF THYMIDINE

The 2-desoxy-ribose nucleosides, first isolated by Levene and London’ by the hydrolysis of thymus nucleic acid, are characterized by their extreme ease of hydrolysis by very dilute mineral acids. Thus, guanine-2-desoxy-riboside is completely hydrolyzed by heating with 0.01 N hydrochloric acid during 5 minutes. Since the rate of hydrolysis is of the same order as that of the furanosides, it was considered possible that the 2-desoxy-ribonucleosides, similarly to the ribonucleosides, have the furanoside ring structure. When, however, it was discovered2 that methyl-2-desoxyglucopyranoside is almost as readily hydrolyzed, it appeared just as feasible that the natural derivatives might have the pyranoside ring structure. Hence the question of their ring structure was in need of further special investigation. We have now studied the ring structure of the sugar portion of thymidine (thymine-2-desoxy-riboside). This substance is found to react with triphenylmethyl chloride in pyridine to give a monotrityl derivative. Since it was shown by us3 that the analogous monotrityl uridine is the 5-substituted derivative, the formation of a monotrityl thymidine might, of itself, be considered a good indication that thymidine is, likewise, a furanoside. Definite proof of this conclusion was provided by substituting the remaining free hydroxyl group by a tosyl group and examining the behavior of the resulting monotosyl trityl thymidine on treat-