A new isolate of the rhodospirillum fulvum group and its photosynthetic pigments

Summary The present paper reports the isolation of an obligate phototrophic bacterium which belongs to the Rhodospirillum fulvum-group on the basis of its colour, morphology, nutritional requirements and strictly anaerobic nature. p-Aminobenzoic acid was shown to be the only growth factor required. Rhsp. fulvum synthesizes bacteriochlorophyll a as its only chlorophyllous pigments. The carotenoid composition comprises lycopene (I) and rhodopin (II) as the major components; traces of 1,2,1,2-tetrahydro-1,1-dihydroxy-lycopene (III) were also present.

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Zusammenfassung Es wird die Isolierung eines obligat phototrophen Bakteriums beschrieben, welches auf Grund seiner Farbe, Morphologie, Nährstoff-Bedürfnisse und streng anaeroben Lebensweise in die Rhodospirillum fulvum-Gruppe eingeordnet wird. Als einzigen Wachstumsfaktor benötigt der Stamm p-Aminobenzoesäure. Rhsp. fulvum bildet Bacteriochlorophyll a als einzigen chlorophyllartigen Farbstoff. Die Hauptmenge der Carotinoide besteht aus Lycopin (I) und Rhodopin (II); es sind außerdem Spuren von 1,2,12-Tetrahydro-1,1-dihydroxy-Lycopin (III) nachgewiesen.

     

Localization of 5′-nucleotidase in bovine brain myelin fraction and myelin subfractions

Purified myelin from fresh calf brain white matter was subfractionated in a discontinuous sucrose gradient; significant recovery of protein and 2,3-cyclic nucleotide 3-phosphohydrolase (CNP) and 5-nucleotidase (5N) activities occurred in all three obtained subfractions, the highest recovery being in the light subfraction; highest 5N and CNP specific activities were in medium myelin. Purified myelin was also subfractionated in a continuous sucrose gradient, with a similar localization of protein; CNP activity and 5N activity maxima suggest that myelin may be a predominant locus of 5N in bovine brain white matter. Freezing of brain white matter caused an increase in protein and in CNP and 5N total activity recoveries in denser myelin subfractions. Cytochemistry showed the reaction product of 5N in the whole myelin fraction to be associated with the innermost, outermost and medial compact myelin layers. Effects of non-ionic detergent (Lubrol WX) on 5N activity were studied, and the results also suggest the intrinsic nature of 5N as an ectoenzyme in myelin membranes. Lubrol WX was viewed as an advisable detergent for the stimulation of myelin 5N activity, but not for the solubilization of this enzyme.     

Elektronenmikroskopische Verteilung und Spezifität der sauren 5′-Nucleotidase im Zentralnervensystem der Ratte

Zusammenfassung Es wird eine Methode zur ultracytochemischen Darstellung der sauren 5-Nucleotidase im Zentralnervensystem der Ratte beschrieben. Die Ergebnisse werden mit der elektronenmikroskopischen Verteilung der sauren Phosphatase verglichen.In Rückenmark, Medulla oblongata und Endhirn sind beide Enzyme in den Cisternen und Bläschen des Golgi-Apparates sowie Lysosomen lokalisiert. Daneben kommen negative Golgi-Zonen und Lysosomen vor. Bei pH 5,5 tritt die saure Phosphatase zusätzlich in Kern und Ergastoplasma der Nervenzellen auf. Intralysosomal bestehen zwischen der sauren 5-Nucleotidase und Phosphatase Verteilungsdifferenzen.Gegenüber Hemmsubstanzen verhalten sich diese Enzyme unterschiedlich, wobei die Wirkung des Inhibitors von seiner Konzentration und dem untersuchten Areal abhängt.

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Electron microscopic distribution and specifity of acid 5-nucleotidase in the central nervous system of the rat

Summary A method for the ultracytochemical demonstration of acid 5-nucleotidase has been described in the central nervous system of the rat. The results were compared with those obtained for acid phosphatase.In the spinal cord, medulla oblongata and fore brain both enzymes are localized in the cisterns, vesicles and vacoules of the Golgi apparatus as well as in lysosomes. Some Golgi cisterns and lysosomes do not react. In addition at pH 5.5 acid phosphatase can be observed in the nucleus and in the ergastoplasm of the nerve cells. Concerning the intralysosomal distribution these enzymes exhibit some differences.Following pretreatment with various inhibitors differences occur between acid 5-nucleotidase and phosphatase depending also from the concentration of the substance used and the region investigated.

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Herrn Dr. R. Gossrau, Anatomisches Institut der Universität Würzburg/BRD, danken wir für die Hilfe bei der Manuskriptanfertigung.     

The formation of peptides from the 2′(3′)-glycyl ester of a nucleotide

Summary We have synthesized 2(3)-O-(glycyl)-adenosine-5-(O-methylphos-phate), an analogue of the 3-terminus of aminoacylated tRNA. A 0.4M solution of this compound maintained at pH 8.2, yields 5.5% of diglycine and 11.5% of diketopiperazine, in addition to the hydrolysis products glycine and adenosine-5-(O-methylphosphate). Under the same conditions, glycine ethyl ester reacts much more slowly, but ultimately gives similar yields of diglycine and diketopiperazine.The aminolysis of 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) by free glycine is relatively inefficient, but serine reacts 20 times more rapidly and yields up to 50% of N-glycylserine. The prebiotic significance of these reactions is discussed.Abbreviations MepA adenosine-5-(O-methylphosphate) - MepA-gly 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) - MepA-bis-gly 2,3-O-(bis-glycyl)-adenosine-5-(O-methylphosphate) - DKP diketopiperazine - gly Et glycine ethyl ester - gly-ser N-glycylserine - O-gly-ser O-glycylserine - O-(gly)-gly-ser O-(glycyl)-glycylserine - Boc-gly N-tert-butyloxycarbonylglycine - MepA-Boc-gly 2(3)-O-(Boc-glycyl)-adenosine-5-(O-methylphosphate) - MepA-bis-Boc-gly 2,3-O-(bis-Boc-glycyl)-adenosine-5(O-methylphosphate) - (gly)₂ diglycine - (gly)₃ triglycine     

A novel PH-CT-COSY methodology for measuring JPH coupling constants in unlabeled nucleic acids. Application to HIV-2 TAR RNA

A quantitative analysis of J_PH scalar couplings in nucleic acids is difficult due to small couplings to phosphorus, the extreme overlap of the sugar protons and the fast relaxation of the spins involved in the magnetization transfer. Here we present a new methodology that relies on heteronuclear Constant Time Correlation Spectroscopy (CT-COSY). The three vicinal ³J_PH3, ³J_PH5 and ³J_PH5 scalar couplings can be obtained by monitoring the intensity decay of the P_i-H3_{i – 1} peak as a function of the constant time T in a 2D correlation map. The advantage of the new method resides in the possibility of measuring the two ³J_PH5 and ³J_PH5 scalar couplings even in the presence of overlapped H5/H5 resonances, since the quantitative information is extracted from the intensity decay of the P-H3 peak. Moreover, the relaxation of the H3 proton is considerably slower than that of the H5/H5 geminal protons and the commonly populated conformations of the phosphate backbone are associated with large ³J_PH3 couplings and relatively small ³J_{PH5 / H5}. These two facts lead to optimal signal-to-noise ratio for the P-H3 correlation compared to the P-H5/H5 correlation.The heteronuclear CT-COSY experiment is suitable for oligonucleotides in the 10–15 kDa molecular mass range and has been applied to the 30mer HIV-2 TAR RNA. The methodology presented here can be used to measure P-H dipolar couplings (D_PH) as well. We will present qualitative results for the measurement of P-H_base and P-H2 dipolar couplings in the HIV-2 TAR RNA and will discuss the reasons that so far precluded the quantification of the D_PHs for the 30mer RNA.     

Synthesis of oligoguanylates on oligocytidylate templates

Summary Short oligocytidylates can act as templates for the self-condensation of guanosine 5-phosphorimidazolide. In the absence of a catalytic metal ion or in the presence of Pb²⁺ a noticeable template effect is already observed with the dimer and the yield of long oligomers reaches a plateau with a hexamer template. Short templates give oligomers longers than the template length. The products are predominantly 2-5 linked for the Pb²⁺-catalyzed reaction while mixed linkages are observed in the uncatalyzed reaction.In the presence of Zn²⁺, a template effect is first observed with the pentamer and is maximal by the heptamer. The products are predominantly 3-5 linked. Oligomers shorter than or as long as the template are obtained in substantial yield, and longer products in much lower yields.Abbreviations G Guanosine - Gp guanosine 2(3)-phosphate - pG guanosine 5-phosphate - Gp! guanosine cyclic 2,3-phosphate - ImpG guanosine 5-phosphorimidazolide - ImpG^* [8-¹⁴C]-guanosine 5-phosphorimidazolide - pGp 5-phosphoguanosine 2(3)-phosphate - G²pG guanylyl-[2-5]-guanosine - G³pG guanylyl-[3-5]-guanosine - ImpGpG 5-phosphorimidazolide of GpG - (pG)_n (n = 2,3) oligomers of pG - GppG P₁, P₂-diguanosine 5-diphosphate - GppGpG 5-[guanosine 5-pyrophosphate] of GpG - NH₂pG guanosine 5-phosphoramidate - (pG)₄₊ tetramer and higher oligoguanylates with 5 terminal phosphate - oligo(G) oligoguanylate - Cp cytidine 2(3)-phosphate - Cp! cytidine cyclic 2,3-phosphate - (Cp)_n–1 Cp! (n= 2,3,4) oligocytidylates terminated by 5-OH groups and 2,3-cyclic phosphates - oligo(C) oligocytidylate - poly(C) polycytidylic acid - poly(U) polyuridylic acid - poly(C,G) random copolymer of C and G - BAP bacterial alkaline phosphatase (E. coli) - EDTA ethylenediaminetetraacetic acid - R_f chromatographic mobility     

Ultracytochemical localization of adenylate cyclase activity in rat thymocytes

Summary Ultrastructural localization of adenylate cyclase (AC) activity was investigated in suspensions of unfixed isolated rat thymocytes using a medium containing 0.6 mM 5-adenylylimidodiphosphate (AMP-PNP) as a substrate, 10 mM MgSO₄ as an activator, 5 mM theophylline as an inhibitor of 3,5-AMP-phosphodiesterase and 2 mM lead nitrate as a capturing agent. AC activity was demonstrated in plasma membrane, perinuclear space, endoplasmic reticulum, Golgi complex, centriole microtubules and mitochondria. AC was activated with 10^–4 M adrenalin in the presence of 5-guanylylimido-diphosphate (GMP-PNP) as well as with 10^–2 M NaF. In the cells incubated in a medium devoid of theophylline and containing 5-AMP instead of AMP-PNP, 5-nucleotidase activity was observed in the same cell structures as AC activity. Hydrolysis of 5-AMP in the nucleus was much stronger than that of AMP-PNP. 10 mM NaF markedly inhibited hydrolysis of 5-AMP in all cell structures. No staining was observed with 2 mM -glycerophosphate as a substrate. Incubation of unfixed thymocytes in media containing AMP-PNP, 5-AMP or p-nitrophenyl phosphate, but not -glycerophosphate, induced both in the nucleus and in the cytoplasm in some cells an appearance of a transitory reticular formation consisting of about 30 nm thick strands which could penetrate the nuclear envelope and plasma membrane and form connections with adjacent cells. The transitory reticular formation seems to belong to the cytoskeleton and to be involved in cell aggregation.     

Topo-optische Reaktionen an der Membran von menschlichen Erythrocytenschatten

Zusammenfassung Frühere Untersuchungen erwiesen, daß die Thiazinfarbstoffe Toluidinblau, Azur A, Azur B, 1:9-Dimethyl-Methylenblau, sowie die Chinolinfarbstoffe N,N-Diäthylpseudoisocyaninchlorid und N,N-6,6-Dichlorpseudoisocyaninchlorid für die topo-optische Reaktion an der menschlichen Erythrocytenmembran geeignet sind. In dieser Studie wird die Verwendbarkeit der Thiazin- und Chinolinfarbstoffe an den menschlichen Erythrocytenschatten gezeigt. Auf Grund der optischen Analyse sind die Thiazinfarbstoffmoleküle radiär zur Membran ausgerichtet, während sich die Chinolinfarbstoffmoleküle membranparallel anlagern.

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Topo-optical reactions on the membrane of the human red cell ghost

Summary Previous studies have proved that the thiazin dyes toluidine blue, azure A, azure B, 1.9-dimethyl methylene blue and the quinolin dyes N,N-diethylpseudoisocyanine chloride, N,N-6,6-dichlorpseudoisocyanine chloride are suitable for topo-optical reaction on the membrane of the red blood cells. In the present study the applicability of the thiazin and quinolin dyes on the membrane of the human red cell ghost was examined. Optical analysis revealed that the thiazin dyes are bound in radial position to the membrane, while the quinolin dyes are bound parallel to the membrane's plane.

     

Oligomerization of deoxynucleoside-bisphosphate dimers: Template and linkage specificity

Evidence is presented that a poly(U) template selectively favors the oligomerization of the activated, 3–5 pyrophosphate-linked dimer pdAppdAp, in comparison with the 3–3 and 5–5 linked dimers. In the absence of poly(U), the 5–5linked dimer is the most reactive, and chains are formed which are more than 60 monomer units in length.Nucleic Acid-Like Structures V. For the previous paper in this series see Visscher and Schwartz (1988).     

Adenosine-5′-phosphosulfate (APS) as sulfate donor for assimilatory sulfate reduction in Rhodospirillum rubrum

Crude extracts of Rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (³⁵S) sulfate, (³⁵S) adenosine-5-phosphosulfate, and (³⁵S) 3-phosphoadenosine-5-phosphosulfate. An enzyme fraction similar to APS-sulfotransferases from plant sources was purified 228-fold from Rhodospirillum rubrum. It is suggested here that this enzyme is specific for adenosine-5-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5-phosphosulfate, however, only at a rate of 1/10 of that with adenosine-5-phosphosulfate. Further, the reaction with 3-phosphoadenosine-5-phosphosulfate was inhibited with 3-phosphoadenosine-5-phosphate whereas this nucleotide had no effect on the reaction with adenosine-5-phosphosulfate. For this activity with adenosine-5-phosphosulfate the name APS-sulfotransferase is suggested. This APS-sulfotransferase needs thiols for activity; good rates were obtained with either dithioerythritol or reduced glutathione; other thiols like cysteine, 2-3-dimercaptopropanol or mercaptoethanol are less effective. The electron donor methylviologen did not catalyze this reaction. The pH-optimum was about 9.0; the apparent K _m for adenosine-5-phosphosulfate was determined to be 0.05 mM with this so far purified enzyme fraction. Enzyme activity was increased with K₂SO₄ and Na₂SO₄ and was inhibited by 5-AMP. These properties are similar to assimilatory APS-sulfotransferases from spinach and Chlorella.Abbreviations APS adenosine-5-phosphosulfate - PAPS 3-phosphoadenosine-5-phosphosulfate - 5-AMP adenosine-5-monophosphate - 3-AMP adenosine-3-monophosphate - 3-5-ADP 3-phosphoadenosine-5-phosphate (PAP) - DTE dithiorythritol - GSH reduced glutathione - BAL 2-3-dimercaptopropanol     

Affinity of guanosine derivatives for polycytidylate revisited

Evidence is presented for complexation of guanosine 5-monophosphate 2-methylimidazolide (2-MeImpG) with polycytidylate (poly(C)) at pH 8.0 and 23°C in the presence of 1.0 M NaCl and 0.2 M MgCl₂ in water. The association of 2-McImpG with poly(C) was investigated using UV-vis spectroscopy as well as by monitoring the kinetics of the nucleophilic substitution reaction of the imidazole moiety by amines. The results of both methods are consistent with moderately strong poly(C) · 2-McImpG complexation and the spectrophotometric measurements allowed the construction of a binding isotherm with a concentration of 2-McImpG equal to 5.55 ± 0.15 mM at half occupancy. UV spectroscopy was employed to establish the binding of other guanosine derivatives on poly(C). These derivatives are guanosine 5-monophosphate (5GMP), guanosine 5monophosphate imidazolide (ImpG), and guanosine 5monophosphate morpholidate (morpG). Within experimental error these guanosine derivatives exhibit the same affinity for poly(C) as 2-McImpG.     

Cleavage of nucleotides by Ce4+ and the lanthanide metal complexes

The cleavage of adenosine-5-monophosphate (5-AMP) and guanosine-5-monophosphate (5-GMP) by Ce⁴⁺ and lanthanide complex of 2-carboxyethylgermanium sesquioxide (Ge-132) in acidic and near neutral conditions was investigated by NMR , HPLC and measuring the liberated inorganic phosphate at 37°C and 50°C. The results showed that 5-GMP and 5-AMP was converted to guanine (G), 5-monophosphate (depurination of 5-GMP), ribose (depurination and dephosphorylation of 5-GMP), phosphate and adenine (A), 5-monophosphate (depurination of 5-AMP), ribose (depurination and dephosphorylation of 5-AMP), phosphate respectively by Ce⁴⁺. In presence of lanthanide complexes, 5-GMP and 5-AMP were converted to guanosine (Guo) and phosphate and adenosine (Ado) and phosphate respectively. The mechanism of cleaving 5-GMP and 5-AMP is hydrolytic scission     

The Humboldt penguinSpheniscus humboldti: a migratory bird?

Until recently, the endangered Humboldt penguin was considered a sedentary bird, which remained near its breeding colonies throughout the year. In this pilot study we used five satellite transmitters on Humboldt penguins during the austral winter and were able to track one bird from Pan de Azúcar Island (26°09S, 70°40W), Northern Chile to Iquique (20°12S, 70°07W), a distance of 640 km, between May 24 and June 26, 1996. While a 35 km protection zone around breeding islands might be helpful to prevent competition of penguins with fisheries during the summer months, this might not improve the survival of migrating birds in the winter. Further studies are required to determine the extent of migration and to confirm the recorded travelling route and landing locations in order to detect possible threats to Humboldt penguins from fishing and other industries throughout the year.

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Zusammenfassung Während noch vor wenigen Jahrzehnten Millionen Humboldtpinguine die Küsten Perus und Chiles bevölkerten, wird die Art heute als gefährdet eingestuft. Die Fischerei stellt die größte Bedrohung für diese Tierart dar, deren Gesamtbestand sich nach letzten Schätzungen nur noch auf 10 000 Individuen beläuft. Wir setzten im Südherbst 1996 fünf Argos-Satellitensender ein, um festzustellen, ob Humboldtpinguine des Naturschutzgebietes Pan de Azúcar (26°09S) im Winter ortstreu bleiben oder saisonale Wanderungen durchführen. Während sich vier der Vögel im Untersuchungszeitraum (18–74 Tage) nicht weiter als 87 km von ihrer Brutinsel entfernten, wanderte ein Vogel im Juni 1996 nach Norden bis vor die Stadt Iquique (20° 12S, 640 km vom Ausgangspunkt entfernt). Obwohl die in einer früheren Studie ermittelte Größe eines marinen Schutzgebietes von 35 km Durchmesser rund um die Brutinsel in den Sommermonaten ausreichend sein mag, belegen die neuen Ergebnisse, daß weitere Untersuchungen über das Wanderverhalten der Humboldtpinguine als Grundlage für einen effektiven Artenschutz unerläßlich sind.

     

Erythrocytenenzyme der Primaten

Zusammenfassung Die Adenosindesaminasen der Primaten zeigen eine genetisch determinierte Variabilität. Bei der Untersuchung von 327 subhumanen Primaten (289 Simiae der Alten Welt, 38 Prosimiae) konnten wir neun Adenosindesaminase-Varianten nachweisen, die auf Grund ihrer unterschiedlichen elektrophoretischen Wandergeschwindigkeit als ADA 6, ADA 4, ADA 2, ADA 2, ADA 1, ADA 3, ADA 5, ADA 5 und ADA 7 bezeichnet werden. Die Verteilung der verschiedenen Phänotypen wurde ermittelt.

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Red cell enzymes of primatesAdenosine deamisnase (EC: 3.5.4.4.)

Summary The polymorphism of adenosine deaminase has been investigated in 327 subhuman Primates (289 Old World Monkeys and 38 Prosimians). Nine adenosine deaminase variants were found to be present, which on the basis of their different electrophoretic mobilities were designated ADA 6, ADA 4, ADA 2, ADA 2, ADA 1, ADA 3, ADA 5, ADA 5 and ADA 7. The distribution of these various phenotypes has been estimated.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Two-dimensional 1H NMR study of two cyclobutane type photodimers of thymidylyl-(3′→5′)-thymidine

2D NMR spectroscopy and J coupling constant analysis are applied to resolve the structure of two photoproducts of thymidylyl-(35)-thymidine. These products are cyclobutane type thymine dimers possessing the cis-syn (the predominant one) and trans-syn geometry. The cis-syn is formed in an ANTI-ANTI conformation about the N-glycosyl linkages and resembles the normal base-stacked configuration. The glycosidic conformation in solution of the 5 terminal fragment differs from the crystal in which the less common SYN conformation is observed. In this isomer only the sugar pucker of the 3 terminal fragment is changed substantially with respect to the dinucleotide. The trans-syn isomer is formed in a SYN-ANTI glycosidic conformation. In this isomer the sugar puckers of both deoxyribose rings are affected and a preference for a pure 2-endo conformation is observed.Abbreviations dTpdT 2-deoxythymidylyl-(35)-2-deoxythymidine - dTp[]dT cyclobutane type photodimers of dTpdT - dTp- and dTp[]- their 5' terminal fragments (fragment A) - -pdT and-[]pdT their 3 terminal fragments (fragment B) - RP-HPLC reversed-phase high-performance liquid chromatography - COSY two-dimensional correlated spectroscopy - 2D NOE two-dimensional nuclear Overhauser spectroscopy     

Formation of P1, P2-dinucleoside 5′-pyrophosphates under potentially prebiological conditions

Summary Organic pyrophosphates such as UppA and NAD are formed when a solution containing a nucleotide, a nucleoside 5-polyphosphate, Mg²⁺ and imidazole are allowed to dry out. We suggest that this synthesis may have occured concurrently with oligonucleotide formation.Abbreviations Im Imidazole - CDI 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride - EDTA ethylenediaminetetraacetic acid - A adenosine - U uridine - p_nA adenosine 5-poly-phosphate containing n phosphate residues - pU uridine 5-phosphate - AppA P₁,P₂-diadenosine 5-pyrophosphate - UppA P₁-(uridine 5)-P₂-(adenosine 5)-pyrophosphate - ImpA adenosine 5-phosphorimidazolide - NMN nicotinamide mononucleotide - NAD nicotinamide-adenine dinucleotide     

Elektronenmikroskopischer Nachweis der 5′-Nucleotidase im Keimzentrum der menschlichen Tonsille

Zusammenfassung An den Keimzentren menschlicher glutaraldehydfixierter Tonsillen untersuchten wir elektronenmikroskopisch die 5-Nucleotidaseaktivität nach der Methode vonWachstein undMeisel. Der Prozentsatz an positiv reagierenden Keimzentrumszellen war insgesamt gering. Unter allen Zelltypen des Keimzentrums fanden sich solche mit deutlich positiver Reaktion. Am häufigsten war die Fermentaktivität an Lymphozyten nachzuweisen, weiterhin auch an Germinozyten und Germinoblasten. Plasmazellen als die am weitesten differenzierten Zellen des Keimzentrums reagierten nur selten positiv. Bei allen Zellen lagen die Reaktionsniederschläge der Plasmamembran teils innen, teils außen an, wobei positive Membrananteile mit fermentnegativen wechselten. Es ist daher anzunehmen, daß das Ferment im Bereich der Plasmamembran lokalisiert ist. Diese Lokalisation entspricht den von verschiedenen Autoren an Zellen anderer Organe elektronenmikroskopisch erhobenen Befunden. Im Gegensatz zu den Resultaten lichtmikroskopischer Untersuchungen konnte im Keimzentrum auch eine Aktivität der Adenosintriphosphatase an den Zellmembranen nachgewiesen werden. Nach dieser elektronenmikroskopischen Untersuchung stellt die 5-N-ase bei pH 7,2 kein Markierungsenzym für einen bestimmten Zelltyp des Keimzentrums dar. Es ist aber noch zu klären, welche zytologischen Fermentaktivitäten sich im sauren pH-Bereich darstellen.

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Electron microscopic study of 5-nucleotidase in the germinal centres of human tonsils

Summary Activity of 5-nucleotidase within germinal centres of human tonsils has been investigated with the electron microscope. Tonsils were fixed in glutaraldehyde and incubated according to the method ofWachstein andMeisel. The percentage of positively reacting germinal centre cells was all together small. All types of germinal center cells can show 5 nucleotidase — activity (lymphocytes, germinocytes, germinoblasts, rarely plasmacells). The reaction product was deposited on the outer or inner face of the plasma membrane. This finding is in accordance with the results of other authors obtained in cell-types from other tissues. In contrast to light microscopical observations, activity of adenosintriphosphatase was also demonstrated on the plasma-membranes. As all cell-types can give a positive reaction, the demonstration of 5-nucleotidase cannot be used for marking one specific cell-type within the germinal centres.

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Diese Untersuchung wurde mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.     

Metabolism of ribosylzeatin-5′-monophosphate by soybean callus

Using cytokinin dependent soybean callus and HPLC analysis it was shown that soybean callus rapidly metabolises ribosylzeatin-5-monophosphate to biologically active compounds which co-chromatographed with trans-ribosylzeatin and trans-zeatin.Abbreviations Z zeatin - RZ ribosylzeatin - RZMP ribosylzeatin-5-monophosphate     

Phagostimulation of the mediterranean fruit fly, Ceratitis capitata by ribonucleotides and related compounds

Females of the medfly, Ceratitis capitata, prefer sucrose solutions containing ribonucleotides to sucrose solutions without them. The order of preference for the nucleotides was: 5GMP>GTP>5CMP>5IMP >dGMP>5UMP>5AMP>5XMP=ATP=2 & 3GMP=RP>3AMP.2AMP, guanosine, inosine, adenine and 5TMP produced no significant stimulation. Females sterilized by irradiation showed reduced attraction to 5GMP as compared to non-irradiated females.Optimal molecular configuration for phagostimulation includes: phosphorylation at the 5 position of the ribose, free hydroxyl groups at 2 and 3 on the ribose, and an NH₂ group at the 2 position of the aromatic ring of purine.It is proposed that the 5GMP in yeast hydrolyzate can be used as a measure of the suitability of the hydrolyzate as a bait.

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Résumé La femelle de la mouche méditerranéenne des fruits, Ceratitis capitata, préfère les solutions de sucrose contenant des ribonucléotides aux simples solutions de sucrose. Lórdre de préférence pour les nucléotides est le suivant: 5GMP>GTP>5CMP>5IMP >dGMP>5UMP>5AMP>5XMP=ATP =2 & 3GMP=RP>3AMP.Le 2AMP, la guanosine, l'inosine, l'adénine et le 5TMP provoquent une stimulation significative. Les femelles montrent aprés stérilisation par irradiation une attirance réduite pour le 5GMP par comparaison avec les femelles non-irradiées.La configuration moléculaire optimale pour la phagostimulation comprend: la phosphorylation en position 5 du ribose; des groupes hydroxyles libres en 2 et 3 sur le ribose; et un groupe NH₂ en position 2 sur le noyau aromatique.Nous proposons que le 5GMP dans l'hydrolysat de levure puisse être utilisé pour mesurer la capacité de l'hydrolysat comme appât.

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Abbreviations 5AMP Adenosine 5-monophosphate - 3AMP Adenosine 3-monophosphate - 2AMP Adenosine 2-monophosphate - dAMP 2-deoxyadenosine 5-monophosphate - ADP Adenosine 5-diphosphate - ATP Adenosine 5-triphosphate - 5GMP Guanosine 5-monophosphate - 2GMP Guanosine 2-monophosphate - 3GMP Guanosine 3-monophosphate - dGMP 2-deoxyguanosine 5-monophosphate - GDP Guanosine 5-diphosphate - GTP Guanosine 5-triphosphate - 5IMP Inosine 5-monophosphate - IDP Inosine 5-diphosphate - ITP Inosine 5-triphosphate - 5XMP Xanthosine 5-monophosphate - 5CMP Cytidine 5-monophosphate - dCMP 2 deoxycytidine 5-monophosphate - CTP Cytidine 5-triphosphate - 5UMP Uridine 5-monophosphate - 5TMP Thymidine 5-monophosphate - RP Ribose 5 monophosphate     

A fluorometric assay of ceramide glycanase with 4-methylumbelliferyl β-d-lactoside derivatives

4-Methylumbelliferyl 6-O-benzyl--d-lactoside (6Bn-MU-Lac) and some related compounds were synthesizedvia different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, theK _m value is 0.232 mM at pH 5. Abbreviations: CGase, ceramide glycanase; Gal, galactose; Glc, Glucose; Lac, lactose; MU, 4-methylumbelliferone; MU-Lac, 4-methylumbelliferyl -d-lactoside; bBn-Lac, 6-O-benzyl-lactose; 6Bn-MU-Lac, 4-methylumbelliferyl 6-Obenzyl--d-lactoside; 46Bd-MU-Lac, 4-methylumbelliferyl 4,6-O-benzylidene--d-lactoside; MU-Cel, 4-methylumbellifery -d-cellobioside; 46Bd-MU-Cel, 4-methylumbelliferyl 4,6-O-benzylidene--d-cellobioside; TLC, thin layer chromatography;¹H-NMR, proton nuclear magnetic resonance; GSL, glycosphingolipids; CSA, 10-camphorsulfonic acid. See Scheme 1 for chemical structures.