Lisianthus vase life after 1-methylcyclopropene and salicylic acid postharvest treatment

This study evaluated the effects of application of 0.5 µl L-1 1-methyl-cyclopropene (1-MCP), 1000 mg L-1 salicylic acid (SA) and the interaction between the two products at room temperature and pre-exposure at 9±2°C for 24 h in maintaining postharvest quality of lisianthus flowers. After applying the treatment, the flowers were kept in jars with water, stored at 24±2°C. The SA treatments proved ineffective, presenting symptoms of phytotoxicity, with high rate of bent neck and yellowing of petals, both at room temperature and in cold storage, and propitiate the emergence of pathogens. The association between 1-MCP in pre-exposure to 9±2°C for 24 h increased the durability of the stems in six days compared to the control treatment, with less symptoms of bent neck and swelling of stems.

Design, synthesis and the effect of 1,2,3-triazole sialylmimetic neoglycoconjugates on Trypanosoma cruzi and its cell surface trans-sialidase

This work describes the synthesis of a series of sialylmimetic neoglycoconjugates represented by 1,4-disubstituted 1,2,3-triazole-sialic acid derivatives containing galactose modified at either C-1 or C-6 positions, glucose or gulose at C-3 position, and by the amino acid derivative 1,2,3-triazole fused threonine-3-O-galactose as potential TcTS inhibitors and anti-trypanosomal agents. This series was obtained by Cu(I)-catalysed azide-alkyne cycloaddition reaction ('click chemistry') between the azido-functionalized sugars 1-N(3)-Gal (commercial), 6-N(3)-Gal, 3-N(3)-Glc and 3-N(3)-Gul with the corresponding alkyne-based 2-propynyl-sialic acid, as well as by click chemistry reaction between the amino acid N(3)-ThrOBn with 3-O-propynyl-GalOMe. The 1,2,3-triazole linked sialic acid-6-O-galactose and the sialic acid-galactopyranoside showed high Trypanosoma cruzi trans-sialidase (TcTS) inhibitory activity at 1.0 mM (approx. 90%), whilst only the former displayed relevant trypanocidal activity (IC(50) 260 mu M). These results highlight the 1,2,3-triazole linked sialic acid-6-O-galactose as a prototype for further design of new neoglycoconjugates against Chagas' disease. (C) 2011 Elsevier Ltd. All rights reserved.

Inhibition of cannabinoid CB1 receptor upregulates Slc2a4 expression via nuclear factor-kappa B and sterol regulatory element-binding protein-1 in adipocytes

Evidences have suggested that the endocannabinoid system is overactive in obesity, resulting in enhanced endocannabinoid levels in both circulation and visceral adipose tissue. The blockade of cannabinoid receptor type 1 (CB1) has been proposed for the treatment of obesity. Besides loss of body weight, CB1 antagonism improves insulin sensitivity, in which the glucose transporter type 4 (GLUT4) plays a key role. The aim of this study was to investigate the modulation of GLUT4-encoded gene (Slc2a4 gene) expression by CB1 receptor. For this, 3T3-L1 adipocytes were incubated in the presence of a highly selective CB1 receptor agonist (1 mu M arachidonyl-2'-chloroethylamide) and/or a CB1 receptor antagonist/inverse agonist (0.1, 0.5, or 1 mu M AM251, 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide). After acute (2 and 4 h) and chronic (24 h) treatments, cells were harvested to evaluate: i) Slc2a4, Cnr1 (CB1 receptor-encoded gene), and Srebf1 type a (SREBP-1a type-encoded gene) mRNAs (real-time PCR); ii) GLUT4 protein (western blotting); and iii) binding activity of nuclear factor (NF)-kappa B and sterol regulatory element-binding protein (SREBP)-1 specifically in the promoter of Slc2a4 gene (electrophoretic mobility shift assay). Results revealed that both acute and chronic CB1 receptor antagonism greatly increased (similar to 2.5-fold) Slc2a4 mRNA and protein content. Additionally, CB1-induced upregulation of Slc2a4 was accompanied by decreased binding activity of NF-kappa B at 2 and 24 h, and by increased binding activity of the SREBP-1 at 24 h. In conclusion, these findings reveal that the blockade of CB1 receptor markedly increases Slc2a4/GLUT4 expression in adipocytes, a feature that involves NF-kappa B and SREBP-1 transcriptional regulation. Journal of Molecular Endocrinology (2012) 49, 97-106

Synthesis of Chromanes and 4H-Chromenes: Exploring the Oxidation of 2H-Chromenes and Dihydro-1-benzoxepines by Hypervalent Iodine(III)

The reaction of various oxygen-containing benzo-fused cycloalkenes were studied with the hypervalent iodine reagent hydroxy(tosyloxy) iodo]benzene [PhI(OH)OTs, HTIB]. 2H-Chromene and 4-methyl-2H-chromene resulted in substituted 4H-chromene and cis-3,4-dialkoxy-4-methyl-3,4-dihydro-2H-chromenes, respectively. Ring contraction to chromanes and benzofurans was observed for dihydrobenzoxepines and 2,2-dimethyl-2H-chromenes, respectively.

Characterization of anti-silencing factor 1 in Leishmania major

Anti-silencing factor 1 (ASF1) is a histone chaperone that contributes to the histone deposition during nucleosome assembly in newly replicated DNA. It is involved in chromatin disassembly, transcription activation and in the cellular response to DNA damage. In Leishmania major the ASF1 gene (LmASF1) is located in chromosome 20 and codes for a protein showing 67% of identity with the Trypanosoma brucei TbASF1a. Compared to orthologous proteins, LmASF1 conserves the main residues relevant for its various biological functions. To study ASF1 in Leishmania we generated a mutant overexpressing LmASF1 in L. major. We observed that the excess of LmASF1 impaired promastigotes growth rates and had no impact on cell cycle progress. Differently from yeast, ASF1 overproduction in Leishmania did not affect expression levels of genes located on telomeres, but led to an upregulation of proteins involved in chromatin remodelling and physiological stress, such as heat shock proteins, oxidoreductase activity and proteolysis. In addition, we observed that LmASF1 mutant is more susceptible to the DNA damaging agent, methyl methane sulphonate, than the control line. Therefore, our study suggests that ASF1 from Leishmania pertains to the chromatin remodelling machinery of the parasite and acts on its response to DNA damage.

Gas-phase reactivity of 2-hydroxy-1,4-naphthoquinones: a computational and mass spectrometry study of lapachol congeners

In order to understand the influence of alkyl side chains on the gas-phase reactivity of 1,4-naphthoquinone derivatives, some 2-hydroxy-1,4-naphthoquinone derivatives have been prepared and studied by electrospray ionization tandem mass spectrometry in combination with computational quantum chemistry calculations. Protonation and deprotonation sites were suggested on the basis of gas-phase basicity, proton affinity, gas-phase acidity (?Gacid), atomic charges and frontier orbital analyses. The nature of the intramolecular interaction as well as of the hydrogen bond in the systems was investigated by the atoms-in-molecules theory and the natural bond orbital analysis. The results were compared with data published for lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone). For the protonated molecules, water elimination was verified to occur at lower proportion when compared with side chain elimination, as evidenced in earlier studies on lapachol. The side chain at position C(3) was found to play important roles in the fragmentation mechanisms of these compounds. Copyright (c) 2012 John Wiley & Sons, Ltd.

Selektive und duale COX-1-, COX-2-Inhibitoren aus der Reihe der Methanone

Zusammenfassung: Prostaglandine (PG) sind wichtige biologische Entzündungsmediatoren, die aus der Arachidonsäure (AA) durch das Enzym Cyclooxygenase (COX) entstehen. Trotz einiger unerwünschter Wirkungen, sind Cyclooxygenase-Hemmer Mittel der Wahl zur Unterdrückung entzündlicher Prozesse. Von der Cyclooxygenase existieren zwei Isoenzyme: COX-1 und COX-2. Eine selektive Hemmung der COX-2 bzw. eine duale Hemmung der COX-1 und COX-2 wird als erfolgversprechendes Prinzip zur Behandlung von entzündlichen Erkrankungen diskutiert.Ziel der Arbeit war die Synthese und in vitro Testung sowie die Erstellung von Struktur-Wirkungs-Beziehungen selektiver bzw. dualer Hemmstoffe der COX-1/-2. Zusätzlich wurden die Substanzen auf inhibitorische Aktivität gegenüber der 5- und 12-Lipoxygenase untersucht.Ausgehend von der Struktur selektiver Hemmstoffe der COX-2 bzw. von dualen COX-1/ COX-2-Inhibitoren sowie von marktüblichen nichtsteroidalen Antirheumatika (NSAR), wurde das Diarylmethanon-Element als Basis gewählt. An diesem Strukturelement wurden Modifikationen vorgenommen, um selektive Hemmstoffe der COX-2 bzw. duale COX-1/ COX-2-Hemmstoffe zu erhalten.Die synthetisierten Verbindungen lassen sich in [4-(Methylsulfanyl)phenyl]- und [4-(Methylsulfonyl)phenyl](aryl)methanone, N-(Aroylphenyl)sulfonamide und -amide sowie (Hydroxyphenyl)(2-thienyl)methanone unterteilen.In der Reihe der [4-(Methylsulfanyl)phenyl](aryl)methanone sind potente Hemmstoffe sowohl der COX-1 als auch der COX-2 erhalten worden. Im Gegensatz dazu zeigen die [4-(Methylsulfonyl)phenyl](aryl)methanone gegenüber COX-1 und COX-2 keine inhibitorische Aktivität. Mit dem 2-Thienylderivat wurde ein potenter, dualer Hemmstoff beider Cyclooxygenase-Isoenzyme identifiziert, dessen Wirkstärke (bezüglich der COX-2) auf den Austausch von Phenyl gegen 2-Thienyl zurückzuführen ist.Die N-(Aroylphenyl)sulfonamide und -amide bilden die umfangreichste Gruppe bei den durchgeführten Untersuchungen, wobei besonders die regioisomeren N-(2-Aroylphenyl)sulfonamide und -amide eingehender studiert wurden. Auf der Basis der (2-Aroylphenyl)sulfonamide läßt sich für die Hemmung der COX-1 eine Struktur-Wirkungs-Beziehungen formulieren, die anhand Hilfe geeigneter Verbindungen überprüft wurde. Die Untersuchungen wurden zum Teil auch auf die 3- und 4-Regioisomeren ausgedehnt, wobei sich die erhaltenen Struktur-Wirkungs-Beziehungen bestätigten. Die Arylsulfonamide inhibieren bevorzugt die COX-1. Auch (4-Aroylphenyl)sulfonamide wurden auf mögliche inhibitorische Aktivität untersucht. Die Einbindung des Amidstickstoffs in ein Indolin- bzw. Tetrahydrochinolin-Ringsystem oder des Sulfonamids in ein 1,3-Propansultam führte in jedem Falle zu wenig aktiven Verbindungen gegenüber der COX-1. N-(2-Aroylphenyl)amide zeigten in Übereinstimmung mit der Hypothese an der COX-1 eine gute inhibitorische Aktivität.Aus der Reihe der (Hydroxyphenyl)(2-thienyl)methanone wurden die freien Alkohole, die Methylether und verschiedene Ester dargestellt und auf COX-1-Aktivität untersucht. Acetate, aber auch Phenole sind die potentesten Inhibitoren der COX-1. Als günstigte Positionen für die 2-Thienylcarbonyl-Einheit am Hydroxyphenylrest erweist sich die ortho- bzw. para-Position.

Synthese, n.c.a. 18F-Markierung und Evaluierung von Antagonisten der Strychnin-unempfindlichen-Glycinbindungsstelle auf Basis der 4-Amino-5,7-Dichlor-1,2,3,4-Tetrahydro-Chinolin-2-Carbonsäure

ZUSAMMENFASSUNGDer glutamaterge N-Methyl-D-aspartat-Rezeptor (NMDA) ist ein wichtiger ionotroper Rezeptor, der die exzitatorische synaptische Transmission im zentralen Nervensystem von Säugetieren vermittelt. Der NMDA-Rezeptor nimmt unter den Glutamatrezeptoren dabei eine Sonderstellung ein, da er mit einer Reihe von neurodegenerativen Erkrankungen wie dem Morbus Parkinson, dem Morbus Huntington, dem Morbus Alzheimer, der Schizophrenie und der Epilepsie in Zusammenhang gebracht wird. Daher besteht ein großes Interesse an der Entwicklung geeigneter 18F-markierter NMDA-Rezeptorliganden zur nicht-invasiven Visualisierung des NMDA-Rezeptorkomplexes mittels der Positronenemissionstomographie.Die 19F-Analoga ADTC1, tADTC1 und tADTC3 - 5 und das nicht-fluorierte 12C-Analogon tADTC2 wurden synthetisiert und ihre in-vitro Affinität und Lipophilie bestimmt. Mit Ausnahme von ADTC1 und tADTC5 die mikromolare Affinitäten besitzen, haben die Liganden in [H-3]MDL-105,519 Rezeptorbindungsassays niedrige nanomolare Affinitäten für die Glycinbindungsstelle. Die Lipophilie der Verbindungen wurde mit drei verschiedenen Verfahren untersucht und ergab logD7,4-Werte von ungefähr 1 für cADTC1 und tADTC1 – 4, während tADTC5 mit einem logD7,4 von –1,15 eine sehr niedrige Lipophilie aufwies. Die Radiosynthesen der 18F-Liganden wurden hinsichtlich der Umsetzung der Markierungsvorläufer mit 2-[F-18]Fluorethyltosylat oder [F-18]Fluorid untersucht und optimiert. Die höchsten radiochemischen Ausbeuten von ungefähr 90% wurden, unter Verwendung von NaOH als Hilfsbase, bei der 18F-Fluorethylierung von t[F-18]ADTC4 und t[F-18]ADTC5 mit 2-[F-18]Fluorethyltosylat erzielt.

Relationship of porcine IGF2 imprinting status to DNA methylation at the H19 DMD and the IGF2 DMRs 1 and 2

BACKGROUND: Porcine IGF2 and the H19 genes are imprinted. The IGF2 is paternally expressed, while the H19 gene is maternally expressed. Extensive studies in mice established a boundary model indicating that the H19 differentially methylated domain (DMD) controls, upon binding with the CTCF protein, reciprocal imprinting of the IGF2 and the H19 genes. IGF2 transcription is tissue and development specific involving the use of 4 promoters. In the liver of adult Large White boars IGF2 is expressed from both parental alleles, whereas in skeletal muscle and kidney tissues we observed variable relaxation of IGF2 imprinting. We hypothesized that IGF2 expression from both paternal alleles and relaxation of IGF2 imprinting is reflected in differences in DNA methylation patterns at the H19 DMD and IGF2 differentially methylated regions 1 and 2 (DMR1 and DMR2). RESULTS: Bisulfite sequencing analysis did not show any differences in DNA methylation at the three porcine CTCF binding sites in the H19 DMD between liver, muscle and kidney tissues of adult pigs. A DNA methylation analysis using methyl-sensitive restriction endonuclease SacII and 'hot-stop' PCR gave consistent results with those from the bisulfite sequencing analysis. We found that porcine H19 DMD is distinctly differentially methylated, at least for the region formally confirmed by two SNPs, in liver, skeletal muscle and kidney of foetal, newborn and adult pigs, independent of the combined imprinting status of all IGF2 expressed transcripts. DNA methylation at CpG sites in DMR1 of foetal liver was significantly lower than in the adult liver due to the presence of hypomethylated molecules. An allele specific analysis was performed for IGF2 DMR2 using a SNP in the IGF2 3'-UTR. The maternal IGF2 DMR2 of foetal and newborn liver revealed a higher DNA methylation content compared to the respective paternal allele. CONCLUSIONS: Our results indicate that the IGF2 imprinting status is transcript-specific. Biallelic IGF2 expression in adult porcine liver and relaxation of IGF2 imprinting in porcine muscle were a common feature. These results were consistent with the IGF2 promoter P1 usage in adult liver and IGF2 promoter P2, P3 and P4 usages in muscle. The results showed further that bialellic IGF2 expression in liver and relaxation of imprinting in muscle and kidney were not associated with DNA methylation variation at and around at least one CTCF binding site in H19 DMD. The imprinting status in adult liver, muscle and kidney tissues were also not reflected in the methylation patterns of IGF2 DMRs 1 and 2.

Probing The Active And Allosteric Binding Sites Of Soybean Lipoxygenase-1

Soybean lipoxygenase-1 is a model for lipoxygenase activity. While the mechanism of oxygenation is understood, the substrate binding mechanism has not yet been elucidated. Two putative binding mechanisms are the ¿head-first¿ and ¿tail-first¿ models, in which the carboxy-terminus or the methyl terminus of the fatty acid substrate is inserted into the active site while the remainder of the molecule protrudes from the surface, respectively. Previous work has demonstrated that derivatization of fatty acid substrates with D-tryptophan increases active site affinity. It has also been shown that while polyunsaturated fatty acids are the natural substrates of lipoxygenases, monounsaturated fatty acids can be oxygenated at a much slower rate. Starting with a monounsaturated fatty acid, oleic acid, as a platform, the molecule N-oleoyl-D-tryptophan (ODT) was synthesized with the anticipation of it being a potent competitive substrate-analogue inhibitor that could be used to discern the substrate binding mechanism. Inhibition kinetics demonstrated that this molecule functions as a partially competitive inhibitor, through an unknown mechanism. The implication behind partially competitive inhibition is that substrate and inhibitor molecules can bind simultaneously to the enzyme, which alludes to the presence of an allosteric binding domain. To investigate the possibility of an inhibitor binding site on the non-catalytic subunit, limited proteolysis was used to cleave the subunits apart which should have eliminated inhibition. Interestingly, it was observed that at high substrate concentrations the inhibitor was completely ineffective, but at low substrate concentrations the inhibitor maintained its standard efficacy. A satisfactory explanation for these results has not yet been determined.

Enzymatic Activity of Soybean Lipoxygenase-1 on Linoleoyl-Derivatized Agarose

Soybean lipoxygenase-1 (SBLO-1) catalyzes the oxygenation of linoleic acid to form 13(S) and 9(R) hydroperoxides. The manner in which substrates bind to the lipoxygenase family of enzymes is not known. It is believed fatty acid substrates may bind either with the aliphatic end first or with the carboxylate group facing the interior of the protein. This thesis tested a potential methyl-end first substrate binding mechanism by studying the activity of SBLO-1 to oxygenate immobilized linoleoyl residues attached to an insoluble polymer. Linoleic acid was attached to aminohexyl agarose in the presence of N-(3- dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC) and Nhydroxysuccinimide (NHS). The concentration of the covalently attached residues was facilitated by enriching linoleic acid with a small amount of the radioactive 14C-isotope. Functionalization yields of 3% available primary amines on the resin were obtained. Enzymatic oxygenation of the linoleoyl-residues was verified using the ferrous oxidation in xylenol orange (FOX) assay. Approximately 30% of the attached linoleoyl moieties were converted to hydroperoxides in the presence of SBLO-1. A disulfide-containing cleavable linker, cystamine, was used as part of an improved method to isolate the product in a facile manner. Cystamine was attached to NHS-activated agarose with approximately 5% overall functionalization yield of available functional groups. 14C-linoleic acid was successfully covalently linked to the cystamine moieties in the presence of EDC and NHS. The FOX assay verified the enzymatic oxygenation of the linoleoyl residues attached to cystamine-derivatized agarose. The isolation of the peroxide product was attempted in a series of extractions in organic solvents. The product was analyzed using GC/MS which did not show a new peak indicative of product. Further work is needed to successfully analyze the stereoand regiochemistry of the oxygenated product. The presence of the peroxides in this study indicated the linoleoyl residues behave as substrates of SBLO-1. It is unknown how bulky substrates bind to the active site; however, it is difficult to rationalize a carboxylate group-first binding mode. Discovery of the 13(S)-hydroperoxide product on the linoleoyl-agarose would support the claim of a potential methyl-end first binding mechanism.

Synthesis Of Linoleate Analogs With Longer Alkyl Termini To Test For Proposed "Tail-First" Binding In SBLO-1

Lipoxygenases are nonheme-iron proteins that catalyze the oxygenation of polyunsaturated fatty acids to give conjugated diene hydroperoxides. For example, soybean lipoxygenase-1 (SBLO-1) converts linoleate into 13-(S)-hydroperoxy-9(Z),11(E)-octadecadienoate (13(S)-HPOD). Although the crystal structure of SBLO-1 has been determined, it is still unclear how the substrate binds at the active site. This absence of knowledge makes it difficult to understand the role of the enzyme during catalysis of the reaction. We hypothesize that SBLO-1 binds linoleate ¿tail-first¿, so that the methyl terminus is within a hydrophobic pocket deep within the enzyme. It is believed that the hydrophobic residue phenylalanine-557 at this site has stabilizing interactions with the terminal methyl group on linoleate. To test this hypothesis, we have developed a synthetic pathway that will yield linoleate analogs with longer fatty acid chains by 1 and 2 more carbons at the alkyl terminus. These substrates will be analyzed through kinetic assays done in combination with wild type SBLO-1 and mutants in which we have replaced phenylalanine-557 with valine.

Study Of The Binding Of Substrate By The Phe557Val Mutant Soybean Lipoxygenase-1

Lipoxygenases are a class of enzymes which consist of non-heme iron dioxygenases that are produced by fungi, plants, and mammals and catalyze the oxygenation of polyunsaturated fatty acid substrates to unsaturated fatty acid hydroperoxide products. The unsaturated fatty acid hydroperoxide products are stereo- and regiospecific. One such lipoxygenase, soybean lipoxygenase-1 (SBLO-1), catalyzes the conversion of linoleate to 13-hydroperoxy-9(Z),11(E)-octadecadienoate (13-HPOD) and a small amount of 9-hydroperoxy-10(E),12(Z)-octadecadienoate (9-HPOD). Although the structure of SBLO-1 is known and it is the most widely studied lipoxygenase, how it binds to substrate is still poorly understood. Two competing binding hypotheses that have been used to understand and explain the binding are the head first binding model and the tail first binding model. The head first binding model predicts linoleate binds with its polar carboxylate group in the binding pocket and the methyl terminus at the surface of the binding pocket. The tail first binding model predicts that linoleate binds with its methyl terminus end in the binding pocket and the polar carboxylate group at the surface of the binding pocket. Both binding models have been used in the explanation of previous work. In previous work the replacement of phenylalanine with valine has been performed to produce the phe557val mutant SBLO-1. The mutant SBLO-1 was then used in the enzymatic oxygenation of linoleate. With this mutant, the amount of 9-HPOD that is formed increases. This result has been interpreted using the head-first binding model in which the smaller valine residue allows linoleate to bind with the polar carboxylate group of linoleate interacting with arginine-707. The work presented in this thesis confirms the regiochemical results of the previous work and further tests the head-first binding model. If head-first binding occurs, the 9-HPOD is expected to have primarily S configuration. Utilizing chiral-phase HPLC, it was found that the 9-HPOD produced by the phe557val mutant SBLO-1 is primarily S, consistent with head-first binding. The head-first binding model was also tested using linoleyl dimethylamine (LDMA), which has been shown to be a good substrate for SBLO-1 at pH 7.0, where LDMA is thought to be positively charged. This model predicts that less of the 9-peroxide should be produced with this substrate. Through the use of gas chromatography/mass spectrometry, it was found that the conversion of LDMA by the phe557val mutant SBLO-1 resulted in the formation of a 46:54 mixture of the 13-peroxide:9-peroxide. The higher amount of 9-peroxide is the opposite of what is expected for the currently proposed model suggesting that the proposed model may not be entirely correct. The results thus far have been consistent with reverse binding but not with the proposed interaction of the polar end of the substrate with arginine-707.

Synthesis and in vitro characterization of radioiodinatable benzodiazepines selective for type 1 and type 2 cholecystokinin receptors

Radiolabeled antagonists of specific peptide receptors identify a higher number of receptor binding sites than agonists and may thus be preferable for in vivo tumor targeting. In this study, two novel radioiodinated 1,4-benzodiazepines, (S)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (9) and (R)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (7), were developed. They were characterized in vitro as high affinity selective antagonists at cholecystokinin types 1 and 2 (CCK(1) and CCK(2)) receptors using receptor binding, calcium mobilization, and internalization studies. Their binding to human tumor tissues was assessed with in vitro receptor autoradiography and compared with an established peptidic CCK agonist radioligand. The (125)I-labeled CCK(1) receptor-selective compound 9 often revealed a substantially higher amount of CCK(1) receptor binding sites in tumors than the agonist (125)I-CCK. Conversely, the radioiodinated CCK(2) receptor-selective compound 7 showed generally weaker tumor binding than (125)I-CCK. In conclusion, compound 9 is an excellent radioiodinated nonpeptidic antagonist ligand for direct and selective labeling of CCK(1) receptors in vitro. Moreover, it represents a suitable candidate to test antagonist binding to CCK(1) receptor-expressing tumors in vivo.

A New Class Of Potential Chloroquine Resistance Reversal Agents For Plasmodia: Syntheses And Biological Evaluation 1-[(3’-Diethylaminopropyl)-3-(Substituted Phenylmethylene)-Pyrrolidines

1-[(3’-Diethylaminopropyl)-3-(substitutedphenylmethylene) pyrrolidines] were synthe-sized and evaluated for CQ resistant reversal activity. The compounds of the series elicit better biological response than their phenyl methyl analogues in general. The most active compound 4b has been evaluated in vivo in details and the results are presented. The possible mode of action of the compounds of this series is by inhibition of the enzyme heme oxygenase, thereby increasing the levels of heme and hemozoin, which are lethal to the parasite.