Acid Silver Nitrate Research Articles

Differential utilization of long chain fatty acids during fasting-induced triacylglycerol depletion. III. Comparison of n−3 and n−6 fatty acids in rat plasma and liver

Previous research has shown that arachidonic acid (20:4( n−6)) is preferentially retained in liver triacylglycerol in fasted compared to fed rats consuming a diet containing n−6 fatty acids. It was hypothesized that eicosapentaenoic (20:5( n−3)) docosahexaneoic acids (22:6( n−3)) would be similarly retained in liver and plasma triacylglycerol of fasted rats consuming a diet containing n−3 fatty acids. In comparison with fed rats, it was observed that in partially fasted rats conusuming diets which contained 5% sunflower oil (78% 18:2( n−6)) or 5% marine fish oil (30% 20:5( n−3) and 22:6( n−3)), both liver and plasma had significantly depleted triacylglycerol levels containing higher proportions of both arachidonic and docosahexaneoic acids but a lower proportion of eicosapentaenoic acid (marine fish oil group only). Separation of liver and plasma triacylglycerol by silicic acid column chromatography and silver nitrate TLC showed that the majority of long chain fatty acids utilized during fasting were derived from the triacylglycerol subclasses containing palmitic acid (16:0), palmitoleic acid (16:1( n−7)) and oleic acid 18:1( n−9)) with retention of both highly saturated and polyunsaturated subclasses. Greater utilization of eicosapentaenoic acid than either arachidonic acid or docosahexaenoic acid during fasting may be due to triacylglycerol speciation of the former with readily oxidized monounsaturated fatty acids.

Culture of PNKT-4B cells at invasion permissive and restrictive temperatures. I. Chromosomal analysis

PNKT-4B is an aneuploid cell line derived from a herpesvirus-induced renal adenocarcinoma of Rana pipiens that displays restricted invasion at 21 degrees C or cooler and invasion at 23 degrees C through 28 degrees C. Metaphase chromosomes obtained from subcultures (passages 297; 345-347) grown at 18 degrees C or 28 degrees C were Giemsa stained or N-banded with acidic silver nitrate. Cells grown at 18 degrees C displayed a modal chromosome number of 41, while 28 degrees C cultures displayed a modal number of 40. The distribution of the chromosomes suggests that the two temperatures may be allowing growth of different subclonal populations. N-banding of chromosomes at both temperatures revealed an increase of active nucleolar organizer regions (NORs) over normal frog tissues, 2/2N. Analysis of 200 N-banded spreads from cells grown at each temperature revealed modal numbers of 9 NORs/cell and modal numbers of 6 NOR-containing chromosomes/cell. Nine specific NOR-containing chromosomes were identified and scored. Similar distributions were observed at 18 degrees C and 28 degrees C. The data imply that the modal number of PNKT-4B has shifted since it was first described, 39, and differs at invasion-permissive and -restrictive temperatures. Increased numbers of active NORs and alterations of NOR-containing chromosomes imply an amplification of rDNA over the amount in normal frog.

The Ultrastructure of the Organic Phase Associated with the Inorganic Substance in Calcified Tissues

An organic phase is closely associated with the mineral substance is all calcified matrices, where it can be demonstrated as crystal-bound proteins by biochemical methods and as crystal ghosts by electron microscopy. Interest in crystal ghosts derives chiefly from the observation that they have the same shape, arrangement, and orientation as inorganic crystallites, which suggests they may have a role in their formation. Histochemically, crystal ghosts of epiphyseal cartilage react with colloidal iron (pH 2.0), acidic phosphotungstic acid, ruthenium red, and a number of cations including calcium, barium, magnesium, lanthanum, strontium, and terbium chloride. Their reactivity is removed by methylation and only incompletely restored by saponification. Moreover, the crystal ghosts located at the periphery of the calcified areas contain vic-glycol groups, as shown by their reactivity with periodic acid-silver nitrate and periodic acid-thiosemicarbazide-osmium. All these reactions show that the crystal ghosts of epiphyseal cartilage contain acidic, probably sulfate groups and, at least initially, vic-glycol groups. Their reactivity decreases as the calcification process is completed. Although the available data are not sufficient to allow a full understanding of the nature and function of these structures, they seem to play an important role in calcification. The hypothesis is presented that crystal ghosts are preformed in calcifying matrices and are activated by the unmasking of the reactive groups in their polymeric molecule; the unmasked groups then link up with inorganic ions in such a way to form organic-inorganic structures the inorganic ions of which are arranged in an apatitelike configuration and the filamentlike shape of which is the same as that of the polymeric molecule.

Fast horizontal electrophoresis. II. Development of fast automated staining procedures using PhastSystem™

The development of equipment for fast automated staining is described. It is possible to handle staining procedures with up to 20 steps and nine different solutions. To increase the reaction rate in the reaction chamber, the gels are rotated and high temperatures are used. The temperature in the reaction chamber is controlled between room temperature and 50 degrees C. Increased temperature, above 20 degrees C, generally results in faster staining and destaining. However, some reactions proceed better at a low temperature, including fixation of proteins with TCA, and the development step in silver staining, where increased temperatures cause a high background stain. Silver staining using acidic silver nitrate solution is preferred, due to easy preparation and good storage stability of the reagents. This method also causes little precipitation of silver on the walls of the reaction chamber. Silver staining is accomplished within one hour. Staining with PhastGel Blue is accomplished within 30 min.

The Occurrence, Type and Location of Calcium Oxalate Crystals in the Leaves of Fourteen Species of Araceae*

The occurrence, type and location of calcium oxalate crystals in the leaves of 14 species belonging to the family Araceae were studied by light microscopy. The Pizzolato test and the Rubeanic acid-silver nitrate test, used to chemically identify and locate the crystals in cross sections of laminae, showed the presence of four types of crystals: druses, raphides, prismatics and crystal sand. Styloids were not observed in any of the species. Crystals identified as calcium oxalate were observed in each tissue layer of the leaf blade, druses occurring more frequently in the palisade mesophyll layers, raphides more often in the spongy mesophyll. Prismatics were sparse, occurring in the mesophyll of only two species. Specialized spindle-shaped crystal idioblasts, located in the spongy mesophyll in all cases, were observed in seven of the 14 aroids. Crystal sand and variations in crystal forms were most frequently observed to be calcium compounds other than calcium oxalate.

On the specificity of alcoholic acidic silver nitrate reagent for the histochemical localization of ascorbic acid. A reappraisal.

The specificity of the alcoholic acidic silver nitrate staining method for the histochemical localization of ascorbic acid was reappraised. It was found that the method is by and large better suited for the localization of ascorbic acid in both animal and plant tissues due to its greater specificity, which is ensured by employing reagent made in carbon dioxide saturated glass distilled water as well as by carrying out the reaction at a low temperature (0-4 degrees C) and at a pH of 2-2.5.

Primary acid silver nitrate fixation of enterochromaffin and murine mast cells.

Primary acid silver nitrate fixation of enterochromaffin and murine mast cells.

Is alcoholic acidic silver nitrate reagent really specific for the histochemical localization of ascorbic acid.

The histochemical localization of ascorbic acid in plant tissues with the alcoholic acidic silver nitrate reagent is shown here to be not specific for ascorbic acid, since some of the polyphenolic substances, including flavonoids, which are known to be widely distributed in plant tissues, are also able to reduce the acidic alcoholic silver nitrate reagent at low temperature (0-4 degrees C) and at pH 2 to 2.5 in dark. This method may perhaps be used for animal tissues where flavonoid pigments do not occur in such large quantities as they do in plants. I therefore, come to the inevitable conclusion that the use of alcoholic acidic silver nitrate reagent in localizing ascorbic acid in plant tissues may be highly misleading.

Histochemical observations on the dark brown pigment granules found in the kidney tissue of rainbow trout.

Histochemical examinations were made on the dark brown pigment granules found in the interstitial tissue of rainbow trout kidney. The pigment granules reduced a solution of acid or ammoniacal silver nitrate to metallic silver. They were slowly bleached by 10% hydrogen peroxide. Furthermore, they became bleached by a mixture of sulfuric acid and potassium permanganate in the oxidizing process of GOMORI's chrome-hematoxylin and phloxine stain, after fixing with dichromate-free fluids. On the other hand, these pigment granules were negative for PAS reaction and BUNTING's prussian blue test, and also were not stainable with sudan black B. From these histochemical results, the pigment granules were identified as melanins.

Evidence for Cytokinin in Bacterial Leaf Nodules of Psychotria punctata (Rubiaceae)

Cytokinin activity based on two bioassays was at least 100-fold higher in Psychotria punctata leaf discs with bacterial nodules than in discs without them. Nodulated discs from young leaves yielded 0.4 to 6 mug of cytokinin (zeatin equivalents) per g fresh weight of leaf tissue, whereas non-nodulated discs from the same leaves yielded 0 to 0.003 mug per g fresh weight. These estimates probably include free-base cytokinins and, if present, any nucleoside cytokinins precipitable by acidic silver nitrate. Cytokinin concentrations in Psychotria leaf nodules appear to be higher than normally found in green leaves of other plants. In l-butanol-acetic acid-water (12:3:5, v/v), the one peak of activity chromatographed with an R(F) similar to zeatin's, but both number and identity of the active substance(s) remain unknown. These findings suggest that a cytokinin is produced by bacteria in leaf nodules of P. punctata and that it is involved in the symbiosis.

Growth spiral patterns in electrodeposited silver

To study the mechanism of crystal growth, silver electrodeposition on silver single crystal (100) surface was investigated by means of a differential interference microscope. The deposition was performed from an acid silver nitrate bath containing a small amount of the additives at various current densities. It was found that poly-amideamine played an important role in the conditions under which spirals grew. The screw dislocation groups of large Burgers vectors are produced by adding additives to the electrolytes, which indicates the importance of the impurities in the formation of screw dislocation groups. A mechanism for the formation of macro-steps by drawing together monatomic steps is discussed in terms of “step-bunching”. Several patterns of spiral growth, which were very useful to know the mechanism of basic crystal growth, were observed in electrodeposited silver. The growth patterns for two or more spirals on the deposit are also reported in relation to the theory of crystal growth.

The Conversion of Cholesterol to Δ5,7,22-Cholestatrien-3β-ol by Tetrahymena pyriformis

The protozoan Tetrahymena pyriformis was incubated in a growth medium containing added unlabeled cholesterol or 26-14C-cholesterol with the following consequences: (a) the biosynthesis of tetrahymanol, a pentacyclic triterpenoid alcohol produced in the organism by squalene cyclization, was inhibited, and (b) the cholesterol was accumulated by the cells and converted metabolically to a mixture of other sterols containing Δ5,7,22-cholestatrien-3β-ol(7,22-bisdehydrocholesterol) as the major component, together with 22-dehydrocholesterol and possibly a small amount of 7-dehydrocholesterol. These three sterols, along with unconverted cholesterol, were obtained in the unsaponifiable lipid fraction from the cells, and were separated from one another by silicic acid-silver nitrate column chromatography of the corresponding acetylated derivatives. The 22-dehydrocholesterol and the recovered cholesterol were rigorously identified by comparisons of various chromatographic, spectral, and other properties of the alcohols and their acetates with those of authentic samples. The tentative identification of the 7-dehydrocholesterol was based on chromatographic comparisons of the acetate derivative with authentic material. The structure of the 7,22-bisdehydrocholesterol, a previously unknown compound, was established on the basis of ultraviolet, infrared, nuclear magnetic resonance, and mass spectral data for both the free sterol and its acetate derivative, and also by chemical conversions of the acetate to known compounds. Thus, hydrogenation of the 7,22-bisdehydrocholesteryl acetate with a Raney nickel catalyst gave lathosteryl acetate, and periodate-permanganate oxidation of the triene acetate gave isovaleric acid. It is suggested that the conversion of cholesterol to 7,22-bisdehydrocholesterol in the cells proceeds by way of either 7-dehydrocholesterol or 22-dehydrocholesterol as intermediate.

On the specificity of the alcoholic, acidic silver nitrate reagent for the histochemical localization of ascorbic acid.

The specificity of the alcoholic acidic silver nitrate staining method for the histochemical localization of ascorbic acid was reappraised. It was found that the method is by and large better suited for the localization of ascorbic acid in both animal and plant tissues due to its greater specificity, which is ensured by employing reagent made in carbon dioxide saturated glass distilled water as well as by carrying out the reaction at a low temperature (0–4° C) and at a pH of 2–2.5.

Investigations of adsorption of unsaturated fatty acid methyl esters on silicic acid-silver nitrate

Investigations of adsorption of unsaturated fatty acid methyl esters on silicic acid-silver nitrate

The analysis of fats containing cyclopropenoid fatty acids

Cyclopropenoid compounds are labile in the presence of acidic reagents, silver nitrate and mercuric acetate; they are partially destroyed in the course of gas-liquid chromatographic analysis; and they give a mixture of straight and branched-chain acids on hydrogenation.The difficulties associated with the isolation of methyl sterculate and of the analysis of fats for sterculic and malvalic acids are discussed.

Separation of Isomers of Methyl Octadecenoate and Methyl Octadecadienoate by Silicic Acid-Silver Nitrate Column Chromatography

Cis, trans isomers of octadecenoate and octadecadienoate were chromatographed on the silicic acid-silver nitrate column. Gas chromatographic and spectrophotometric analysis of the elute showed that the components were separated into six groups.1) Trans-9, 10 and 11-octadecenoate.2) Trans, trans- (9, 11) and (10, 12) -conjugated octadecadienoate. 3) Cis, trans- (9, 11) and (10, 12) and (11, 13) -conjugated octadecadienoate and cis-l3-octadecenoate.

Metal reduction reactions of the melanins: histochemical studies.

In general the melanins are argentaffin and, except in hair cortex, reduce ferric ferricyanide. Cutaneous and ocular melanins reduce acid silver nitrate, more promptly in guinea pigs than in man and rhesus monkeys. This reduction is slower than that of ammoniacal silver nitrate. It may be accelerated so as to occur in one or two minutes by prior reduction of the melanins by sodium hydrosulfite. Neuromelanin reduces acid silver nitrate very slowly (2-3 days) and prior hydrosulfite reduction does not induce rapid reductivity for acid silver. Acetylation has no influence on the reductivity of melanin for acid or ammoniacal silver or ferric ferricyanide. But, if applied to cutaneous and ocular melanins after reduction with hydrosulfite, it then greatly impairs the reduction of acid silver nitrate, but not of ammoniacal silver. Acetylation similarly influences the reductivity of catechol toward the acid and ammoniacal silver solutions. Oxidation has two general effects on the melanins, an irreversible bleaching by the more drastic oxidants, and a reversible abolition or impairment of their reducing capacity toward acid and ammoniacal silver solutions and ferric ferri cyanide. The oxidants vary in their effect on the silver and ferric ferricyanide reactions, so that some are more effective against the argentaffin reactions, others against the ferric ferricyanide reaction. Likewise the cutaneous, ocular and nerve cell melanins show differences in loss of reductivity with the various oxidants. Tumor melanins seem somewhat less reactive to silver than adjacent normal tissue melanins. Ocular tumor melanin resembles chorioidal melanin more than the epithelial melanins of the retina, ciliary and iris. The argentaffin reaction of cutaneous and ocular melanin is probably assignable to the presence of quinhydrone groupings which may be reversibly oxidized to quinones and reduced to diphenols. This type of grouping does not appear to be present in neuromelanin. Neuromelanin, from this and from the other recorded differences, appears to be a distinct substance, perhaps not even closely related chemically to the other melanins.

METAL REDUCTION REACTIONS OF The MELANINS: SILVER AND FERRIC FERRICYANIDE REDUCTION BY VARIOUS REAGENTS IN VITRO

Test tube reactions of 163 reagents with silver solutions are recorded in tabular form. The silver solutions used were silver nitrate at pH 4 and at pH 6, ammoniacal silver nitrate, all at about 25°C., and Gomori's methenamine silver at 60°C. Ferric ferricyanide reduction is also included in the tables for comparison. Of the substances tested 30 quite promptly reacted with acid silver nitrate as well as the other reagents, 28 gave delayed reactions with acid, prompt with alkaline silver, 24 gave variable acid, and delayed alkaline silver reactions, 27 gave no reaction with acid silver and delayed reactions with alkaline, 16 reacted slowly with hot methenamine silver and not or scarcely at all with cold ammoniacal silver. The remaining 38 reactants did not blacken with silver solutions. Also tabulated are the pigment formation reactions of 13 polyphenols, indoles and sulfur amino acids with chromic acid, potassium bichromate, potassium chromate, periodic acid, sodium iodate and potassium chlorate.

Trichoxanthin, the yellow granular pigment of guinea pig hair follicles and hairs.

Trichoxanthin is a granular yellow pigment occurring in hair matrix and hair medulla of yellow and red guinea pig skin. It is insoluble in organic and dilute mineral acids, water and organic solvents, irregularly soluble in dilute alkali and promptly removed by methylation though not by acidified higher aliphatic alcohols. It reduces ferric ferricyanide and ammoniacal silver promptly, acid silver nitrate slowly. Indole reactions, azo-coupling reactions and Gibbs's phenol reaction are negative. It is strongly basophil at pH 1 and binds ferrous ions, in these characters resembling melanin. It is more promptly bleached by HNO3, CrO3, KMnO4 and CH3CO3H than is cutaneous melanin of the same species and its reduction reactions are more rapidly affected by oxidants. Reduction of acid silver nitrate is not appreciably accelerated by prior hydrosulfite reduction, in distinction from melanin. On the basis of the modifications of the metal reduction reactions by oxidants and reductants, the possibility of a p-quinhydrone structure is suggested.

Amino-silver staining of nervous tissue.

Silver-on-the-slide staining of mounted paraffin sections of nervous tissue, fixed either in 95% ethyl alcohol or 10% solutions of formalin (plain, formol-saline or neutralized), can be successfully and easily accomplished when an amino acid-silver nitrate solution, with metallic copper added, is used for the impregnating agent. An equal-parts mixture of 0.035 M solution of glycine, dl-methionine, dl-α-amino-n-butyric acid, dl-histidine (free base) or dl-α-alanine (or combinations of these) and 0.02 M solution of AgNO3 is adjusted to pH 8.0-8.5 with 0.1 M NaOH. Clean, bright Cu is used in the proportion of one 1.5 × 6.5 cm strip to every 50 ml of silver solution. The technic recommended is: (1) Pour 150-200 ml of the silver-amino acid solution into a 350-400 ml staining dish. (2) Drop 3-4 strips of Cu into the dish and distribute them evenly over the bottom. (3) Place the slides (in a glass carrier) into the solution immediately and allow them to remain at 37°C for 24-48 hr. (4) Complete the procedure as ...