Showing papers on "Thin-layer chromatography published in 1974"

19-HydroxyIated E prostaglandins as the major prostaglandins of human semen

Abstract: ALMOST 30 years after the initial discovery of the prostaglandins, Bergstrom et al., succeeded in isolating and identifying prostaglandins (PGs) E1, E2, F1α and F2α from sources including human semen1. It was subsequently claimed2 that the 19-hydroxy derivatives of prostaglandins A and B were also present. These compounds were later found at an average concentration of 40 µg ml−1 (ref. 3), In a detailed study of semen PGs we have used a new approach for the measurement of the E prostaglandins, which involves protecting the unstable β-ketol system by oximation in the unextracted semen, thus ensuring minimal degradation to the A or B series. Using this technique we found that the levels of 19-hydroxy derivatives of PGA and PGB are relatively low whereas two new PGs, later identified as 11α,15,19-trihydroxy-9-keto prost-13-enoic acid (19-hydroxy PGE1) and 11α,15,19-trihydroxy-9-keto prosta-5,13-dienoic acid (19-hydroxy PGE2) were present at an average total concentration of 100 µg ml−1. These compounds can be isolated together as the methyl ester/methyl oxime derivatives by thin layer chromatography and the individual components can be separated by gas chromatography as the methyl ester/methyl oxime/tert-butyl dimethyl silyl ethers4.

Structure, Gas Chromatographic Measurement, and Function of Suberin Synthesized by Potato Tuber Tissue Slices

Abstract: The polymeric material (suberin) of the wound periderm of potato tuber slices was analyzed after depolymerization with LiAIH4 in tetrahydrofuran or BF3 in methanol with the use of thin layer chromatography, chemical modification, and combined gas-liquid chromatography and mass spectrometry. Fatty acids (C16 to C26), fatty alcohols (C16 to C26), octadec-9-ene-1, 18-dioic acid, and 18-hydroxy-octadec-9-enoic acid were identified to be the major components. Based on the structural information that the two bifunctional C18 molecules constituted a major portion of suberin, a gas chromatographic method of measuring suberization was developed. This method consisted of hydrogenolysis of powdered tissue followed by thin layer chromatography and gas chromatographic measurement of octadecene-1, 18-diol as the trimethylsilyl ether. With this assay it was shown that the development of resistance to water loss by the tissue slices was directly proportional to the quantity of the bifunctional C18 molecules, thus providing evidence that a function of suberin is prevention of water loss.

Studies on the reduction of tetrazolium salts. 3. The products of chemical and enzymic reduction.

Abstract: 1. Formazans have been prepared from chromatographically pure MTT, NBT and NT (a) by chemical reduction in a test tube, and (b) by enzymic reduction in tissue sections. 2. The formazans were analysed (a) by spectrophotometry in solution, (b) by microdensitometry in tissue sections, and (c) by thin layer chromatography. 3. MTT produces one formazan. This can exist in several forms depending (a) on the polarity of the solvent or tissue component with which it is associated, and (b) on the presence of chelating metal ions. 4. NBT and NT each produce two formazans. A reddish ethanol-soluble polar compound is a half-reduced intermediate, and a bluish ethanol-insoluble non-polar compound is the fully reduced di-formazan. These products can be measured separately. 5. There was no evidence for the existence of any free radical formazan intermediates in formazans extracted from incubated sections.

Occurrence ofcis-5,cis-9-Hexacosadienoic andcis-5,cis-9,cis-19-Hexacosatrienoic acids in the marine spongeMicrociona prolifera

Abstract: Fatty acid analysis of the total lipids from the marine spongeMicrociona prolifera by gas liquid chromatography on an EGSS-X column revealed two major peaks with equivalent chain length values of 27.08 and 27.74. Each of these components was isolated as a separate band by thin layer chromatography on AgNO3-silicic acid. Characterization of the two unknowns by IR spectroscopy, NMR, hydrogenation, and gas liquid chromatography revealed that the unknown acids weren-26∶2 andn-26∶3 containing only nonmethylene interruptedcis-double bonds. Reductive ozonolysis identified the 26∶2 ascis-5,cis-9-hexacosadienoic acid and the 26∶3 ascis-5,cis-9,cis-19-hexacosatrienoic acid. Analysis of the fatty acid composition ofMicrociona total lipids showed 14% 26∶2 and 31% 36∶3. The neutral lipids, phosphatidylethanomaline, and phosphatidylserine all contained >41% C26 acids; but only 4% C26 was present in the phosphatidylcholine.

Quantitative and qualitative analyses of isolated lipid droplets from interstitial cells in renal papillae from various species

Abstract: The lipid droplets of renal papillae homogenates from four different species were obtained by ultracentrifugation. Ca. 80–98% of the lipids (triglycerides, phospholipids, free fatty acids, and cholesterol esters) consist of triglycerides. The triglycerides were fractionated by argentation thin layer chromatography and each fraction characterized by gas liquid chromatography. No fraction contained any unique triglyceride. The fatty acid composition of the total triglycerides, as analyzed by gas liquid chromatography and ozonolysis, differed markedly from the fatty acid composition of the corresponding plasma triglycerides. The papillary triglycerides were characterized by higher concentrations of stearic acid, arachidic acid, and polyunsaturated acids with 20 or more carbon atoms. Particularly interesting was the presence in the lipid droplets of docosa-7,10,13,16-tetraenoic acid. This acid has been shown to be a major component in the cholesterol ester fraction of rat and canine adrenal lipids. In the papillary triglycerides, this acid accounted for 7%, 15%, and more than 20% of the total fatty acids in the dog, rat, and rabbit, respectively. The pig differs from these three species in having only ca. 1% of this acid. These observations suggest that the interstitial cells produce these triglycerides. This production could occur either by a transacylation from phospholipids and cholesterol esters and by a de novo synthesis from locally produced fatty acids. The possibility that the triglyceride production may be involved in a control of the prostaglandin production of the renal medulla is discussed.

[4] Separation of cyclic nucleotides by thin-layer chromatography on polyethyleneimine cellulose

Abstract: Publisher Summary Thin-layer chromatography (TLC) on anion-exchange layers is a versatile method for the fractionation and purification of cyclic nucleotides and related compounds. Polyethyleneimine (PEI) cellulose was introduced and shown to be superior to other materials by K. Randerath. Although other anion-exchange celluloses and nonionic layers can be used and have been applied in the laboratory, this chapter is restricted to PEI-eellulose. The chapter is outstanding with regard to sharpness of resolution and versatile applicability. This chapter shows the principal possibilities for the separation of cyclic nucleotides, especially adenosine 3', 5'-monophosphate (cAMP) 1 and guanosine 3', 5'-monophosphate (cGMP), from related nucleotides and from their possible biological degradation products, nueleosides, bases, and uric acid.

Studies in seed dormancy : VIII. The identification and determination of gibberellins A1 and A 9 in seeds of Corylus avellana L.

Abstract: The three major fractions (II, III and V) of the five fractions of gibberellin (GA)-like activity obtained by the thin layer chromatographic purification of an extract of hazel embryos have been examined by gas liquid chromatography and combined gas chromatography-mass spectrometry. By these techniques GA1 was identified as the methyl ester trimethylsilyl ether in fraction II and GA9 as the methyl ester in fraction V. Both substances were clearly separated from other components by gas liquid chromatography so that accurate determination of their concentrations was possible. GA1 accounted for most of the activity found by bioassay in fraction II while GA9 accounted for only part of the activity of fraction V. The GA-like substances in the less biologically active thin layer chromatography fractions have not yet been identified.Freshly harvested seeds contained GA1 but GA9 was not detected. After 28 days dry storage and 42 days imbibition and chilling at 5°, the GA1 content was very low and GA9 was still below the limits of detection. On subsequent exposure of the seeds to a temperature of 20° for 8 days, there was a 40-fold increase of GA1 and at least a 300-fold increase of GA9.

Structure and Biosynthesis of Cuticular Lipids: Hydroxylation of Palmitic Acid and Decarboxylation of C(28), C(30), and C(32) Acids in Vicia faba Flowers.

Abstract: The structure and composition of the cutin monomers from the flower petals of Vicia faba were determined by hydrogenolysis (LiAlH4) or deuterolysis (LiAlD4) followed by thin layer chromatography and combined gas-liquid chromatography and mass spectrometry. The major components were 10, 16-dihydroxyhexadecanoic acid (79.8%), 9, 16-dihydroxyhexadecanoic acid (4.2%), 16-hydroxyhexadecanoic acid (4.2%), 18-hydroxyoctadecanoic acid (1.6%), and hexadecanoic acid (2.4%). These results show that flower petal cutin is very similar to leaf cutin of V. faba. Developing petals readily incorporated exogenous [1-14C]palmitic acid into cutin. Direct conversion of the exogeneous acid into 16-hydroxyhexadecanoic acid, 10, 16-dihydroxy-, and 9, 16-dihydroxyhexadecanoic acid was demonstrated by radio gas-liquid chromatography of their chemical degradation products. About 1% of the exogenous [1-14C]palmitic acid was incorporated into C27, C29, and C31n-alkanes, which were identified by combined gas-liquid chromatography and mass spectrometry as the major components of the hydrocarbons of V. faba flowers. The radioactivity distribution among these three alkanes (C27, 15%; C29, 48%; C31, 38%) was similar to the per cent composition of the alkanes (C27, 12%; C29, 43%; C31, 44%). [1-14C]Stearic acid was also incorporated into C27, C29, and C31n-alkanes in good yield (3%). Trichloroacetate, which has been postulated to be an inhibitor of fatty acid elongation, inhibited the conversion of [1-14C]stearic acid to alkanes, and the inhibition was greatest for the longer alkanes. Developing flower petals also incorporated exogenous C28, C30, and C32 acids into alkanes in 0.5% to 5% yields. [G-3H]n-octacosanoic acid (C28) was incorporated into C27, C29, and C31n-alkanes. [G-3H]n-triacontanoic acid (C30) was incorporated mainly into C29 and C31 alkanes, whereas [9, 10, 11-3H]n-dotriacontanoic acid (C32) was converted mainly to C31 alkane. Trichloroacetate inhibited the conversion of the exogenous acids into alkanes with carbon chains longer than the exogenous acid, and at the same time increased the amount of the direct decarboxylation product formed. These results clearly demonstrate direct decarboxylation as well as elongation and decarboxylation of exogenous fatty acids, and thus constitute the most direct evidence thus far obtained for an elongation-decarboxylation mechanism for the biosynthesis of alkanes.

Enzymatic Utilization of P1-Di-N-acetylchitobiosyl P2-Dolichyl Pyrophosphate and Its Chemical Synthesis

Abstract: Fully acetylated chitobiose was treated with phosphoric acid to give a mixture of products from which 2-acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β- D-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-α,β- D-glucopyranosyl phosphate (Ac3GlcNAc-Ac2GlcNAc-P) was isolated by preparative thin layer chromatography. Treatment of this compound with P1-diphenyl P2-dolichyl pyrophosphate gave an acetylated pyrophosphate diester, which was purified chromatographically and deacetylated. The product, P1-di-N-acetylchitobiosyl P2-dolichyl pyrophosphate (Dol-P-P-GlcNAc-GlcNAc), was readily separated from P1-2-acetamido-2-deoxy-α-D-glucopyranosyl P2-dolichyl pyrophosphate (Dol-P-P-GlcNAc) by thin layer chromatography in several solvent systems. Addition of this compound to human lymphocyte membrane preparations led to the formation of a mannose-containing derivative which appears to be an oligosaccharide phospholipid, as judged by its behavior on DEAE-cellulose chromatography and by its hydrolysis to give an oligosaccharide containing more than four monosaccharide units.

Identification of some previously unknown aldehydes in cooked chicken

Abstract: Aldehydes present in a flavor concentrate, obtained from cooked chicken were separated and isolated by means of gas liquid chromatography. Subsequently, they were converted into their 2,4-dinitrophenylhydrazones and identified by thin layer chromatography on Kieselguhr G-Carbowax 750 and Silica Gel G-AgNO3 and by analysis after partial hydrogenation. Finally, they were compared with model substances. Besides the aldehydes which had been found earlier in cooked chicken the following new aldehydes were identified: 3-c-nonenal; 4-c-decenal; 2-t,4-c,7-c-decatrienal; 2-t,5-c-undecadienal; 2-t-dodecenal; 2-t,4-c-dodecadienal; 2-t,6-c- and 2-t,6-t-dodecadienal; 2-t-tridecenal; 2-t,4-c-tridecadienal; 2-t,4-c,7-c-tridecatrienal; and 2-t,4-c-tetradecadienal. Three of them, 4-c-decenal; 2-t,6-c-dodecadienal; and 2-t,4-c,7-c-tridecatrienal are typical breakdown products of arachidonic acid, and to a major extent also 2-t,5-c-undecadienal.

Trace constituents in milk fat: isolation and identification of oxofatty acids.

Abstract: Ca. 1% of the glycerides of milk fat contain oxofatty acids. The isolation, fractionation, and characterization of oxofatty acids were accomplished using the following sequence of steps: (A) transmethylation, (B) conversion into 2,4-dinitrophenylhydrazones, (C) adsorption of the 2,4-dinitrophenylhydrazones on magnesium oxide to eliminate the colorless lipid, (D) fractionation of the 2,4-dinitrophenylhydrazones into non-oxofatty acid and oxofatty acid fractions on alumina, (E) separation of the oxofatty acid 2,4-dinitrophenylhydrazones into saturated and unsaturated classes by argentation column chromatography, (F) separation of these classes by chain length using liquid-liquid column and thin layer partition chromatography, (G) resolution of positional isomers by thin layer chromatography, (H) regeneration of the positional isomer 2,4-dinitrophenylhydrazones, and (I) analysis of the parent oxofatty acids by gas liquid chromatographymass spectrometry. In this manner, 36 saturated and 11 unsaturated oxofatty acids were identified tentatively or positively. The saturated oxofatty acids ranged in chain length from C10–C24, predominantly C18 and C16, and generally contained an even number of carbon atoms. The unsaturated oxofatty acids ranged from C14–C18, with C18 predominating.

Lipids of six cultivated barley (Hordeum vulgare L.) varieties.

Abstract: The lipids of representative varieties of 2-row spring, 6-row spring, and 6-row winter-type barleys were studied. Total barley lipids were classified by silicic acid gel column chromatography and separated by thin layer chromatography, and the fatty acid composition was determined by gas liquid chromatography. Total lipid content of the 6 barley varieties ranged from 3.12%–3.56% (dry wt basis). The average values for neutral lipids, glycolipids, and phospholipids were 71, 9, and 20%, respectively. The fatty acid composition of barley was rather typical of plant tissue. The neutral lipids and glycolipids from all the varieties contained a higher percent of linoleic and linolenic (C 18∶2 and C 18∶3) acids than the phospholipid fraction.

The separation of arsenic-77 in a carrier-free state from the parent nuclide germanium-77 by a thin-layer chromatographic method

Abstract: 77As(III) and77As(V) were separated from neutron-irradiated GeO2 by a thin-layer chromatographic method, in which silica gel was used as adsorbent and a 2∶1 mixture of methanol and 5N HCl as developer. The Rf values of these nuclides were as follows: 0.00 for77Ge, 0.50 for77As(III) and 0.94 for77As(V). The influence of As(III) carrier added before the separation was investigated on the oxidation state of77As recoiled from the parent nuclide. The radiochemical purity of77As thus separated was more than 99.9% and the activity due to77As could easily be eluted with water from the adsorbent, with 93% recovery.

Egg yolk lecithin. A biochemical laboratory project

Abstract: The authors present an undergraduate experiment laboratory project involving lecithin which integrates these key components of thin layer and column chromatography.

Quantitative Thin Layer Chromatography of Amino Acids Using Fluorescamine Reagent

Abstract: Calibration curves are presented for several different types of amino acids to illustrate the quantitation of these compounds by in situ fluorescence densitometry on thin layer plates.