Fluorescence methods for the histochemical demonstration of monoamines

Summary The histochemical fluorescence method of Falck and Hillarp for the demonstration of catecholamines and certain tryptamines, e.g. 5-hydroxytryptamine is based on the principle that these amines can be condensed with formaldehyde to yield strongly fluorescent 6,7-dihydroxy-3,4-dihydroisoquinolines and 6-hydroxy-3,4-dihydro--carbolines respectively. The investigation here reported presents the fluorescence characteristics and relative fluorescence yields for formaldehyde treated biogenic monoamines and certain related compounds enclosed in a dried protein layer. The fluorescence properties of some synthetic 6,7-substituted-3,4-dihydroisoquinolines and 3,4-dihydro--carbolines are given, and the fluorescence characteristics in relation to the molecular structure are discussed.Abbreviations used A adrenaline - DA dopamine - DOPA 3,4-dihydroxyphenylalanine - DOPS 3,4-dihydroxyphenyl-serine - 5-HT 5-hydroxytryptamine - 5-HTP 5-hydroxytryptophan - 5-MT 5-methoxytryptamine - -m-DA -methyl-dopamine - -m-DOPA -methyl-3,4-dihydroxyphenylalanine - -m-NA -methyl-noradrenahne - MTA 3-methoxy-tyramine - NA noradrenaline - NM normetanephrine - T Tryptamine - Try Tryptophan     

Gas chromatographic—mass spectrometric screening procedure for the identification of formaldehyde-derived tetrahydroisoquinolines in human urine

A gas chromatographic—mass spectrometric method has been developed for the identification of 1,2,3,4-tetrahydroisoquinoline and six metabolites extracted from urine in the picogram range. The derivatization procedure for the substances, formed by reaction of formaldehyde with biogenic amines, employs propionic anhydride and can take place in aqueous medium. In this way artificial formation of these compounds via condensation of biogenic amines with aldehydes or α-keto acids during the work-up procedure is eliminated. The procedure results in hydrophobic compounds, which are quantitatively extractable by liquid—liquid extraction with organic solvents. Further clean-up was performed by solid-phase extraction on C₁₈ sample preparation columns.     

Uptake of l-Dopa by cells in the taste buds of the vallate papilla of the mouse

Summary Several precursor substances and biogenic amines were admistered intraperitoneally to mice and were examined by the histochemical formaldehyde induced fluorescence method. It was found that after treatment with l-Dopa a number of cells inside the taste buds showed fluorescence.     

Biogene Amine im Nervensystem von Lineus sanguineus Rathke (Nemertini)

Zusammenfassung Mit Hilfe der von Carlsson, Falck und Hillarp entwickelten Methode zur fluoreszenzmikroskopischen Lokalisation biogener Amine werden im Nervensystem von Lineus sanguineus erstmalig primäre Catecholamine nachgewiesen, von denen auf Grund ihres Verteilungsmusters angenommen wird, daß sie als Transmitterstoffe wirken. Nur wenige Ganglienzellen innerhalb der Nervenzellschicht des Gehirns sind catecholaminerg. Sie versorgen über das Neuropilem von Ganglien und lateralen Nervensträngen im wesentlichen drei periphere, terminale Fasersysteme, die im Bereich der Frontalorgane, des Rüssels und im Mund-Vorderarm-Bereich liegen.Die intraneuronale Verteilung biogener Amine entspricht weitgehend derjenigen im Wirbeltier-Neuron. Wahrscheinlich ist das catecholaminerge Nervensystem im Bereich der Frontalorgane sensibel, im Rüssel und in der Mund-Vorderdarm-Region motorisch. Möglicherweise hat es auch senso-motorischen Charakter. Das Verteilungsmuster der terminalen catecholaminergen Nervenfasernetze wird hinsichtlich einer etwaigen biologischen Bedeutung, die es beim Erwerb der Beute haben könnte, diskutiert.

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Primary catecholamines in the nervous system of lineus sanguineus Rathke (Nemertini)

Summary By the aid of the histochemical fluorescence method of Carlsson, Falck and Hillarp primary catecholamines which might act as transmitters are demonstrated in the nervous system of Lineus sanguineus. There are only a few catecholaminergic cells within the layer of nerve cells of the brain. Via the neuropile of the ganglia and the lateral nerve cords, they mainly supply three peripheric nets of nerve fibers, situated in the frontal organs, in the proboscis and in the mouth-foregut-region.The intraneuronal distribution of the biogenic amines is almost identical with the one in vertebrate neurons. Probably the catecholaminergic nervous system in the frontal organs is a sensory one, and it might be motoric in the proboscis and in the mouth-foregut-region. Possibly its character is both sensory and motoric. The pattern of the distribution of the three terminal nervous plexus is discussed in view of its possible biological relevance during the act of taking the prey.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft     

Tissue uptake of catechol and indole amino acids histochemical studies on the rat iris

Summary Rat irises exposed to DOPA in vitro and subsequently treated with the histochemical technique of Falck and Hillarp for catecholamines show accumulation of a fluorescent formaldehyde condensation product within the capillary endothelial cells. A similar accumulation was observed when rat irises were exposed to 5-OH-Tryptophan and -methyl-dopa but not after exposure to the corresponding amines. Fluorescent products were also observed in the same cells when control irises were treated with the trihydroxyindole histochemical reaction. It is concluded that certain catechol and indole amino acids accumulate within the endothelial cells of the rat iris capillaries in a manner similar to that observed in brain capillaries. Furthermore, small amounts of DOPA are probably present within these cells normally.     

Localization of monoaminergic neurons in the central nervous system of Astacus astacus Linné (Crustacea)

Summary The cellular localization of biogenic monoamines in crustaceans was studied by means of a highly specific and sensitive fluorescence method devised by Falck and Hillarp. It was found that neurons displaying specific fluorescence in the central nervous system were confined to the protocerebrum, the medulla externa and interna and the ventral nerve cord. The method allows a distinction between the fluorophores of 5-hydroxytryptamine (and 5-hydroxytryptophan), which emit the yellow light, and the fluorophores deriving from the catecholamines (and DOPA), which emit the green light. Green-fluorescent neurons occurred abundantly in the aforementioned parts of the central nervous system while yellow-fluorescent neurons were sparsely present in the same parts.The present work has been carried out at the departments of Histology and Zoology at the University of Lund. The authors take great pleasure in expressing their warmest thanks for laboratory facilities, provided by Professors Erik Dahl (Zoological Institute) and Bengt Falck (Histological Institute).The research reported in this document has been sponsored by the Air Force Office of Scientific Research under Grant AF EOAR 66-14 through the European Office of Aerospace Research (OAR), United States Air Force and by a grant from the Swedish Natural Science Research Council 99-32 (nr 5995).     

Tyrosine hydroxylase activity in the central nervous system of the crayfish,Pacifastacus leniusculus (Crustacea,Decapoda)

Summary Tyrosine hydroxylase, responsible for the formation ofl-dopa froml-tyrosine, has been identified in the central nervous system of the crayfish,Pacifastacus leniusculus (Crustacea, Decapoda). It requires pterine as cofactor and is inhibited by a number of known tyrosine hydroxylase inhibitors; iron-chelators, tyrosine analogues and also by the catecholamines, dopamine and noradrenaline. Iron enhances the activity of the enzyme. It differs from the vertebrate tyrosine hydroxylase in having a more alkaline pH optimum and a higher affinity for the pterine cofactor. Kinetic studies were performed andK _m andV _max values are presented. Dopa formed was identified and quantitatively measured by high pressure liquid chromatography (HPLC) and electrochemical detection.     

Solubilization and partial purification of the rabbit parotid Na/K/Cl-dependent bumetanide binding site

Summary We demonstrate that the high affinity bumetanide binding site of the rabbit parotid acinar cell can be extracted from a basolateral membrane fraction using relatively low concentrations (0.07%, wt/vol; 1 mg membrane protein/ml) of the nonionic detergent Triton X-100. This extracted site cannot be sedimented by ultracentrifugation at 100,000 ×g × 1 hr. Bumetanide binding to this site retains the ionic characteristics of bumetanide binding to native membranes but shows a fivefold increase in binding affinity (K d=0.57±0.15 m vs.K d=3.3±0.7 m for native membranes). Inactivation of the extracted bumetanide binding site observed at detergent/protein ratios>1 can be prevented or (partially) reversed by the addition of exogenous lipid (0.2% soybean phosphatidylcholine). When the 0.07% Triton extract is fractionated by sucrose density gradient centrifugation in 0.24% Triton X-100, 0.2% exogenous lipid and 200mm salt, the high affinity bumetanide binding site sediments as a single band withS _20,w =8.8±0.8 S. This corresponds to a molecular weight 200 kDa for the bumetanide binding protein-detergent-lipid complex and represents a sevenfold purification of this site relative to the starting membrane fraction. In contrast to previous attempts to purify Na/K/Cl cotransport proteins and their associated bumetanide binding sites, the present method avoids harsh detergent treatment as well as direct covalent modification (inactivation) of the transporter itself. As a consequence, one can follow the still active protein through a series of extraction and purification steps by directly monitoring its bumetanide binding properties.     

A modification of the histochemical fluorescence method for the improved localization of 5-hydroxytryptamine

Summary By using a modified formaldehyde gas treatment, it has been possible to improve the histochemical fluorescence method for the demonstration of 5-hydroxytryptamine. A certain improvement of the localization of catecholamines has also been obtained.The modified histochemical procedure involves a primary treatment with a formaldehyde gas of a humidity which does not cause any noticeable diffusion. After this it is possible to retreat the tissue specimen with a formaldehyde gas of higher humidity resulting in increased yields of the final fluorescent compounds. In spite of this improvement of the formaldehyde gas technique for the demonstration of 5-hydroxytryptamine, it cannot be considered as sensitive as that for catecholamines. The reasons for this are discussed.     

Mediated uptake of folate by a high-affinity binding protein in sublines of L1210 cells adapted to nanomolar concentrations of folate

Summary An L1210 cell line (JT-1), which can grow in medium supplemented with 1nm folate, has been isolated. These cells exhibit a slower growth rate than folate-replete parental cells and have a lower ability to transport folate or methotrexate via the reduced folate transport system. Measurements at nanomolar concentrations of folate revealed that the adapted cells have acquired a high-affinity folate-binding protein. Binding to this component at 37°C was rapid and reached a maximum value after 30 min which corresponded in amount to 0.23±0.3 pmol/mg protein, and excess unlabeled folate added 30 min subsequent to the [³H]folate led to a rapid release of the bound substrate. Radioactivity bound to or released from the cells after 30 min at 37°C remained as unmetabolized folic acid. Binding was also rapid at 0°C but uptake at the plateau was only one-half the value obtained at 37°C. Half-maximal saturation of the binding component (K _D) occurred at a folate concentration of 0.065nm at pH 7.4, while the affinity for folate decreased 30-fold when the pH was reduced to 6.2 (K _D=2.0nm). 5-Methyltetrahydrofolate was also bound by this component (K _i=13nm at pH 7.4) but with a much lower affinity than for folate, while progressively weaker interactions were observed with 5-formyltetrahydrofolate (K _i=45nm) and methotrexate (K _i=325nm). When the same adaptation procedure was performed with limiting amounts of 5-formyltetrahydrofolate, two additional cell lines, JT-2 and JT-3, were isolated which expressed elevated levels of the folate-binding protein. The binding activity of the latter cells was 0.46 and 1.4 pmol/mg protein, respectively. When the level of binding protein was compared in cells grown at different concentrations of folate, an increase in medium folate from 1 to 500nm caused a sevenfold reduction in binding activity in the JT-3 cell line, while these same growth conditions had no effect on binding by the other cells. These results indicate that L1210 cells adapted to low concentrations of folate or 5-formyltetrahydrofolate contain elevated levels of a high-affinity binding protein and that this protein is able to mediate the intracellular accumulation of folate compounds. L1210 cells thus appear to have two potential uptake routes for folate compounds, the previously characterized anion-exchange system and a second route mediated by a high-affinity binding protein. An additional low-affinity, high-capacity transport system for folate that had been proposed previously was not observed under a variety of experimental conditions in either the adapted or parental cells.     

BspA (CyuC) in Lactobacillus fermentum BR11 Is a Highly Expressed High-Affinity L-Cystine-Binding Protein

The BspA protein of Lactobacillus fermentum BR11 (BR11) is a cell envelope constituent that is similar to known solute-binding proteins and putative adhesins. BspA is required for L-cystine uptake and oxidative defense and is likely to be an L-cystine-binding protein. The aim of this study was to directly measure L-cystine-BspA binding and BspA expression. De-energized BR11 cells bound radiolabelled L-cystine with a Kd of 0.2 M. A bspA mutant could not bind L-cystine. L-cystine-BR11 binding was unaffected by large excesses of L-glutamine, L-methionine, or collagen, indicating L-cystine specificity. BR11 and the bspA mutant were identical in their abilities to bind L-cysteine, indicating that L-cysteine is not a BspA ligand. BspA expression levels were deduced from radiolabelled L-cystine binding and it was found that there are 1–2 × 10⁵ BspA molecules per cell, and that expression is slightly higher under oxidizing conditions. It is proposed that BspA be renamed CyuC.     

Some aspects of the Feulgen reaction in situ

Summary Cytological observations combined with studies on absorption spectra of Feulgen stained normal and lipid — extractet HeLa and ehrlich-Lettré mouse ascites cells were performed after fixation of the cells as well in neutral formaldehyde as in Serra fixative. The effects of formaldehyde treatment of the stained cells to substitute all the free amino groups of DNA bond pararosaniline molecules, were also studied. The results obtained by using DNA samples containing 2% protein and relatively free from protein, led to the conclusion that after acid hydrolysis for a short period purines in DNA become splitted and these released aldehydes react with one or two amino groups of pararosaniline, a triphenylmethane dye (according to the arrangement of purines and pyrimidines in the helices). Some protein molecules also take part in the reaction and substitute some of the free amino groups of DNA bound pararosaniline. Peulgen stained cells fixed in Serra fixative show an absorption maximum at 546–550 m. Under appropriate conditions, as in cells fixed in formaldehyde, other substances e.g. phospholipids and lipoproteins interfere with the reaction by substituting most of the free amino groups of DNA bound pararosaniline molecules. It has been argued that in histochemical reactions monosubstituted pararosaniline molecules should be coloured and further substitution of free amino groups of pararosaniline, bound in DNA helices, does not change the intensity of the colour, but gives a shift in the wavelength of the absorption spectra.It has been suggested that the differential response of the nucleoli to the Feulgen-reaction, depending on whether the cells were fixed in formaldehyde or in Serra fixative, may be due to the formation of a protecting shield around the finely distributed intranucleolar chromatin strands, when formaldehyde is being used. After this fixation lipoproteins and other lipids, present in a relatively high percentage and closely associated with the intranucleolar chromatin strands, are especially well preserved.Evidences have been put foreward in support of the amino alkylsulfonic acid theory of Rumpf (1935) and Hörmann et al. (1958) whereas the amino sulfinic acid theory to explain the Schiffs reaction (Wieland and Scheuing, 1921) was shown not to be in agreement with our results.On leave from the Department of Botany, Calcutta University, 35, Ballygunge Circular Road, Calcutta-19, India; on a fellowship from the German Academic Exchange Service.     

Demonstration of catecholamine and resorcinolamine derivatives as formaldehyde-induced fluorescence in protein models

We assessed in protein droplet models the potential use of the formaldehyde condensation method for histochemical demonstration of a wide range of catecholamines and resorcinolamines. The experiments showed that all of the amines tested, except salbutamol and carbuterol, formed fluorophores, and that the fluorescence was specific [i.e., there was no fluorescence in the absence of formaldehyde, the fluorescence was quenched by water, and the fluorophores were subject to photodecomposition by the exciting (405-nm) light]. Peak wavelengths of the emission spectra were 480-485 nm for fluorophores of resorcinolamine derivatives. The fluorescence intensity of the catecholamines was greater than that of the resorcinolamines. Fluorophore formation was not hindered by substitution of t-butyl, phenylisoprophyl, or p-hydroxyphenylisopropyl on the amino-N in catecholamines (t-butylnorepinephrine, Cc24, Cc25, respectively) or resorcinolamines (terbutaline, Th1161, fenoterol, respectively), and fluorophores also formed for catecholamines with the amino-N in a ring structure (rimiterol) or with a long alkyl chain substituted on the amino-N (hexoprenaline). Our study showed that fluorescence microphotometry can be used to detect a range of drugs that are catecholamines or resorcinolamines, and hence it should be possible to use this technique to study the properties of dissipation of these amines in tissues.     

Na−K−2Cl cotransport in winter flounder intestine and bovine kidney outer medulla: [3H] bumetanide binding and effects of furosemide analogues

Summary The effects of several sulfamoyl benzoic acid derivatives on Na–K–Cl cotransport were investigated in winter flounder intestine. The relative efficacy (IC₅₀ values) and order of potency of these derivatives were benzmetanide, 5×10^–8 m> bumetanide 3×10^–7 m>piretanide 3×10^–6 m>furosemide 7×10^–6 m> amino piretanide 1×10^–5 3-amino-4-penoxy-5-sulfamoyl benzoic acid. Binding of [³H] bumetanide was studied in microsomal membranes from winter flounder intestine and compared to that in bovine kidney outer medulla. Binding was also studied in brush-border membranes from winter flounder intestine. The estimated values forK _d and number of binding sites (n) were: bovine kidney,K _d =1.6×10^–7,n=10.5 pmol/mg protein; winter flounder intestine,K _d 1.2×10^–7,n=7.3 pmol/mg protein, and brush-border membranes from winter flounder,K _d =5.3×10^–7,n=20.4 pmol/mg protein. The estimatedK _d for bumetamide binding to winter flounder brush-border membranes derived from association and dissociation kinetics was 6.8×10^–7 m. The similarity in magnitudes of IC₅₀ andK _d for bumetanide suggests that the brush-border cotransporter is ordinarily rate-limiting for transmural salt absorption and that bumetanide specifically binds to the cotransporter. Measurement of bumetanide binding at various concentrations of Na, K and Cl showed that optimal binding required all three ions to be present at about 5mm concentrations. Higher Na and K concentrations did not diminish binding but higher Cl concentrations (up to 100mm Cl) inhibited bumetanide binding by as much as 50%. Still higher Cl concentrations (500 and 900mm) did not further inhibit bumetanide binding. Scatchard analysis of bumetanide binding at 5 and 100mm Cl concentrations showed that bothK _d andn were lower at the higher Cl concentration (5mm Cl:K _d =5.29×10^–7 m,n=20.4 pmol/mg protein; 100mm Cl:K _d =2.3×10^–7 m,n=8.8 pmol/mg protein). These data suggest two possibilities: that bumetanide and Cl binding are not mutually exclusive (in contrast to pure competitive inhibition) and that they each bind to separate sites or that two distinct bumetanide binding sites exist, only one of which exhibits Cl inhibition of binding. This inhibition would then be consistent with a competitive interaction with Cl.     

The Na+-independentd-glucose transporter in the enterocyte basolateral membrane: Orientation and cytochalasin B binding characteristics

Summary Phloridzin-insensitive, Na⁺-independentd-glucose uptake into isolated small intestinal epithelial cells was shown to be only partially inhibited by trypsin treatment (maximum 20%). In contrast, chymotrypsin almost completely abolished hexose transport. Basolateral membrane vesicles prepared from rat small intestine by a Percoll^® gradient procedure showed almost identical susceptibility to treatment by these proteolytic enzymes, indicating that the vesicles are predominantly oriented outside-out. These vesicles with a known orientation were employed to investigate the kinetics of transport in both directions across the membrane. Uptake data (i.e. movement into the cell) showed aK _t of 48mm and aV _max of 1.14 nmol glucose/mg membrane protein/sec. Efflux data (exit from the cell) showed a lowerK _t of 23mm and aV _max of 0.20 nmol glucose/mg protein/sec.d-glucose uptake into these vesicles was found to be sodium independent and could be inhibited by cytochalasin B. TheK _t for cytochalasin B as an inhibitor of glucose transport was 0.11 m and theK _D for binding to the carrier was 0.08 m.d-glucose-sensitive binding of cytochalasin B to the membrane preparation was maximized withl- andd-glucose concentrations of 1.25m. Scatchard plots of the binding data indicated that these membranes have a binding site density of 8.3 pmol/mg membrane protein. These results indicate that the Na⁺-independent glucose transporter in the intestinal basolateral membrane is functionally and chemically asymmetric. There is an outward-facing chymotrypsin-sensitive site, and theK _t for efflux from the cell is smaller than that for entry. These characteristics would tend to favor movement of glucose from the cell towards the bloodstream.     

Specific binding sites for corticosterone in isolated cells and plasma membrane from rat liver

Summary The specific binding of [³H]corticosterone to hepatocytes is a nonsaturable, reversible and temperature-dependent process. The binding to liver purified plasma membrane fraction is also specific, reversible and temperature dependent but it is saturable. Two types of independent and equivalent binding sites have been determined from hepatocytes. One of them has high affinity and low binding capacity (K _D=8.8nm andB _max=1477 fmol/mg protein) and the other one has low affinity and high binding capacity (K _D=91nm andB _max=9015 fmol/mg). In plasma membrane only one type of binding site has been characterized (K _D=11.2nm andB _max=1982 fmol/mg). As it can be deduced from displacement data obtained in hepatocytes and plasma membrane the high affinity binding sites are different from the glucocorticoid, progesterone nuclear receptors and the Na⁺,K⁺-ATPase digitalis receptor. Probably it is of the same nature that the one determinate for [³H]cortisol and [³H]corticosterone in mouse liver plasma membrane. Beta-and alpha-adrenergic antagonists as propranolol and phentolamine did not affect [³H]corticosterone binding to hepatocytes and plasma membranes; therefore, these binding sites are independent of adrenergic receptors. The binding sites in hepatocytes and plasma membranes are not exclusive for corticosterone but other steroids are also bound with very different affinities.     

Role of calcium–calmodulin in auxin-induced somatic embryogenesis in leaf base cultures of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> var. HD 2329)

Wheat leaf bases cultured for 1 day on 2,4-d (10 μM) display the induction of somatic embryogenesis. The induction of somatic embryogenesis by 2,4-d appears to be calcium-mediated as treatment of leaf bases with the calcium chelator, EGTA, prior to 2,4-d treatment, inhibited the induction of somatic embryogenesis. This sensitivity of auxin to reduced calcium levels can be reversed by calcium ions alone and not any other divalent cation like magnesium or zinc. Additionally, the expression of the three calcium-regulated genes, Triticum aestivum calmodulin binding protein kinase, calcium-dependent protein kinase, and putative calcium binding protein was analyzed in wheat leaf bases which suggest a specific role for Ca²⁺ in somatic embryogenesis. Application of the calcium ionophore, A23187, either alone or along with 2,4-d, induced somatic embryogenesis. This specificity for calcium was verified both by treatment with the calcium antagonist TMB8, and the elimination of calcium from the medium, resulting in reduction of somatic embryogenesis by 80%. Treatment with calcium channel blockers like verapamil and nifedipine, calcium antagonist, lanthanum, and calmodulin inhibitors chlorpromazine and fluphenazine, prior to the 2,4-d treatment, inhibited induction of somatic embryogenesis. The present study thus provides evidence for the involvement of calcium–calmodulin in the stimulus–response coupling of auxin-induced somatic embryogenesis in wheat leaf base system.     

Failure of equilibrium dialysis to show selective monosaccharide binding by erythrocyte membranes

Summary Equilibrium dialysis has been reported to show stereoselective binding of the preferred sugar transport substrate,D-glucose, by NaI protein extracts of human erythrocyte membranes. However, we were unable to show any detectable differential binding ofD-glucose (as compared with the poorly transported analogue,L-sorbose) with NaI protein extracts. The basis for this decided dissonance is not clear. Extracts with nonionic detergents, various alcohols, and pyridine were also used, but the results with these were also negative. Our data indicate either that the transport sites are not thus extractable in a functional condition, or that only a very small number of binding sites (less than 100,000) are involved with the sugar translocation; and that this method cannot serve to measure the site population unless a far greater concentration of the binding material can be achieved than has so far been possible.     

The effect of methyl jasmonate on accumulation of 2-phenylethylamine and putrescine in seedlings of common buckwheat (<Emphasis Type="Italic">Fagopyrum esculentum</Emphasis>)

The effects of exogenously applied methyl jasmonate on content of biogenic amines: putrescine, spermidine, tyramine, cadaverine and 2-phenylethylamine in seedlings of common buckwheat (Fagopyrum esculentum Moench) were investigated. The studies have shown that methyl jasmonate stimulates the conversion of l-phenylalanine into 2-phenylethylamine and increases the endogenous levels of putrescine in hypocotyls and cotyledons of buckwheat seedlings. Simultaneous feeding the seedlings with l-phenylalanine and methyl jasmonate has indicated that conversion of l-phenylalanine into 2-phenylethylamine can be one of possible reasons, caused by the methyl jasmonate suppression of anthocyanins synthesis in hypocotyls. To our knowledge, the stimulation of conversion of l-phenylalanine into 2-phenylethylamine by methyl jasmonate, as found in the present study, is described for the first time in higher plants.     

A Catecholamine storage in the pancreatic A2-cells of owl monkey (Aotes trivirgatus)

Summary The fluorescence method ofFalck andHillarp was used to study the occurrence of biogenic monoamines in the islets of Langerhans of monkeys. A storage of a catecholamine was demonstrated in the A₂-cells of owl monkey, whereas no histochemically demonstrable amount of monoamines could be seen in the islet cells of marmoset,Rhesus monkey, squirrel monkey, andCebus monkey.Supported by grants from the Swedish Medical Research Council (No. B69-14x-712-04C) and by the National Institutes of Health (No. 06701-02).