Graham Jackson - Academia.edu (original) (raw)
Papers by Graham Jackson
PeerJ
Background Neuropeptides exert their activity through binding to G protein-coupled receptors (GPC... more Background Neuropeptides exert their activity through binding to G protein-coupled receptors (GPCRs). GPCRs are well-known drug targets in the pharmaceutical industry and are currently discussed as targets to control pest insects. Here, we investigate the neuropeptide adipokinetic hormone (AKH) system of the desert locust Schistocerca gregaria. The desert locust is known for its high reproduction, and for forming devastating swarms consisting of billions of individual insects. It is also known that S. gregaria produces three different AKHs as ligands but has only one AKH receptor (AKHR). The AKH system is known to be essential for metabolic regulation, which is necessary for reproduction and flight activity. Methods Nuclear magnetic resonance techniques (NMR) in a dodecylphosphocholin (DPC) micelle solution were used to determine the structure of the three AKHs. The primary sequence of the S. gregaria AKHR was used to construct a 3D molecular model. Next, the three AKHs were individ...
Background. Neuropeptides exert their activity through binding to G-protein coupled receptors (GP... more Background. Neuropeptides exert their activity through binding to G-protein coupled receptors (GPCRs). GPCRs are well-known drug targets in the pharmaceutical industry and are currently discussed as targets to control pest insects. Here we investigate the neuropeptide adipokinetic hormone (AKH) system of the desert locust Schistocerca gregaria. The desert locust is known for its high reproduction, and for forming devastating swarms consisting of billions of individual insects. It is also known that S. gregaria produces three different AKHs as ligands but has only one AKH receptor. The AKH system is known to be essential for metabolic regulation, which is necessary for reproduction and flight activity. Methods. Nuclear magnetic resonance techniques (NMR) in a dodecylphosphocholin (DPC) micelle solution were used to determine the structure of the three AKHs. The primary sequence of the S. gregaria AKH receptor (AKHR) was used to construct a 3D molecular model. Next, the 3 AKHs were in...
Journal of neurochemistry, 2018
Alzheimer's disease (AD) belongs to one of the most multifactorial, complex and heterogeneous... more Alzheimer's disease (AD) belongs to one of the most multifactorial, complex and heterogeneous morbidity-leading disorders. Despite the extensive research in the field, AD pathogenesis is still at some extend obscure. Mechanisms linking AD with certain comorbidities, namely diabetes mellitus, obesity and dyslipidemia, are increasingly gaining importance, mainly because of their potential role in promoting AD development and exacerbation. Their exact cognitive impairment trajectories, however, remain to be fully elucidated. The current review aims to offer a clear and comprehensive description of the state-of-the-art approaches focused on generating in-depth knowledge regarding the overlapping pathology of AD and its concomitant ailments. Thorough understanding of associated alterations on a number of molecular, metabolic and hormonal pathways, will contribute to the further development of novel and integrated theranostics, as well as targeted interventions that may be beneficial ...
Data in brief, 2017
The data presented in this article are related to the publication "Interaction of the red pi... more The data presented in this article are related to the publication "Interaction of the red pigment-concentrating hormone of the crustacean Daphnia pulex, with its cognate receptor, Dappu-RPCHR: A nuclear magnetic resonance and modeling study" (Jackson et al., 2017) [1]. This article contains the data for homology modeling of the red pigment-concentrating hormone (RPCH) receptor of the water flea, Daphnia pulex (Dappu-RPCHR), which was constructed from its primary sequence. This is the first 3D model of a crustacean G-protein coupled receptor. Docking of the agonist, pGlu-Val-Asn-Phe-Ser-Thr-Ser-Trp amide (Dappu-RPCH), was used to find a binding pocket on the receptor and compared to the binding pocket of the adipokinetic hormone (AKH) receptor from the malaria mosquito. Data for the receptor, with and without loop refinement, together with the docked agonist, are presented.
Journal of Inorganic and Nuclear Chemistry
Journal of inorganic biochemistry, Nov 22, 2017
The advent of biodegradable nanomaterials with enhanced antibacterial activity stands as a challe... more The advent of biodegradable nanomaterials with enhanced antibacterial activity stands as a challenge to the global research community. In an attempt to pursue the development of novel antibacterial medicinal nanotechnology, we herein a) synthesized ionic-gelated chitosan nanoparticles, b) compared and evaluated the antibacterial activity of essential oils extracted from nine different herbs (Greek origin) and their combinations with a well-defined antibacterial Zn(II)-Schiff base compound, and c) encapsulated the most effective hybrid combination of Zn(II)-essential oils inside the chitosan matrix, thereby targeting well-formulated nanoparticles of distinct biological impact. The empty and loaded chitosan nanoparticles were physicochemically characterized by FT-IR, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), with the entrapment and drug release studies being conducted through UV-Visible and atomic absorption techniques. The antimicrobial properties of the n...
AIP Conference Proceedings, 2007
Knowledge of the chemical complexes (speciation) in urine can be extremely important in evaluatin... more Knowledge of the chemical complexes (speciation) in urine can be extremely important in evaluating the risk of crystallization of stone forming salts. In order to determine the speciation, a database of thermodynamic constants for the wide variety of complexes that ...
Journal of Nuclear Medicine, Feb 1, 1996
plex biological fluids. In this article, we describe the chemical speciation of Ga(III) and Gd(II... more plex biological fluids. In this article, we describe the chemical speciation of Ga(III) and Gd(III), two metal ions commonly used to prepare imaging agents and MRI contrast agents respectively. We hope to show how a knowledge of chemical speciation can help to explain existing clinical data and how it can be used in the design of new and more effective agents. ThEORYAND METhODOLOGY Metal Ion Speciation Speciation modeling ofblood plasma was pioneered by Pemn in a series of papers (1). At the same time Sillen (2), Morel (3), Martell (4) and others worked on natural waters and urine. These early models were restricted to one or two metal ions with a limited number of ligands. The development of faster computers with larger memories enabled these early models to be expanded into multicomponent systems. In the blood model developed by May et al. (5), 7 metal ions and 40 ligands were considered simulta neously. An essential process in the development ofany speciation model is to define a series of chemical equilibria which represent the system under investigation. In defining the equilibria all the chemical species involved and the equilibrium constants for the reactions have to be specified (Eq. 1). This is the area of greatest difficulty in speciation modelling as accurate equilibrium constants are not always available. Indeed, in some cases, all the possible equilibria have not been identified. Si â€" 13j @ X@((t.J), Metal chelate ions are commonly used in medical diagnostic imag ing as MRI contrast or imaging agents. The efficacy of these metals depends on their in vivo behavior, which in turn depends on their in vivo speciation. Methods: A computer model has been used to simulate the speciation of Ga3@ and Gd3@ in blood plasma. The model has been tested against known clinical data and then used to investigate Ga3@ uptake by tumor cells. The iatrogenic effect of a gadopentetic acid enhanced MRI scan upon the biodistilbution of 67Gacitratehas also beencalculated. Results:The speciationof @3± calculated using the computer model is concordant with clinical data. The results support transfernn mediated uptake of Ga3@ by tumor cells but also account for GaQII)biodistribution observed in hypotransfemnemicsubjects. Ina study of the effect of gadopentetic acidupon67Gagalliumcitrate,neitherresidual DTPA nor [Gd(DTPA)J2 cause signfficant changes in the speciation of Ga(III).The calculations show that dissociation of 4% of the admin istered gadopentetic acid results in the formation of a mixed, Gd(III) and Ga(III),metal transfernn complex and a 100-fold increase in the concentration of [Ga(OH)@J.Conclusion: Computer simulation is a valuable tool which can be used to explain/understand in vivo behavior of radioactive metal ions.
J Coord Chem, 1989
... ethane; ma1 = malonato; R,-ati = bis(N-alkylbenzoylacetoneiminato); Et = ethyl; Ph = phenyl; ... more ... ethane; ma1 = malonato; R,-ati = bis(N-alkylbenzoylacetoneiminato); Et = ethyl; Ph = phenyl; Bz = benzoyl; Pn-Bu, = iric-(n-butyl-phosphine); ox = oxalato; acac = acetylacetonato; py = pyridine; n-Pr = n-propyl; diars = Nyholm's diarsine; dmso ... M. Schumann and H. Elias, Inorg. ...
Polyhedron, 1991
ABSTRACT A novel copper(II) diaminodiamido complex is presented in which the 5,5,5-membered chela... more ABSTRACT A novel copper(II) diaminodiamido complex is presented in which the 5,5,5-membered chelate is more stable than the 5,6,5-membered chelate analogue.
Spectroscopy Letters, 1988
... METAL(I1) BIS(AQU0) COMPLEXES OF 8-HYDROXYQUINOLINE Carola Engelter, Graham E Jackson, Cheryl... more ... METAL(I1) BIS(AQU0) COMPLEXES OF 8-HYDROXYQUINOLINE Carola Engelter, Graham E Jackson, Cheryl L Knight, and David A Thornton ... Vogel A, A Textbook of Practical Organic Chemistry, 3rd ed. Longmans, London and New York, 1967, p. 830. Merritt L L, Anal. ...
Journal of Coordination Chemistry, 1989
Deuteration of 8-aminoquinoline (aq) at the amino groups and comparison of the infrared spectrum ... more Deuteration of 8-aminoquinoline (aq) at the amino groups and comparison of the infrared spectrum of aq with those of aniline and quinoline enables reliable assignments to be proposed for the amino stretching and bending modes and the internal modes of the aminoquinoline rings. The spectra of the tris(8-aminoquinoline) complexes of iron, cobalt and nickel perchlorates have been examined over the
The stoichiometry, stability constants and solution structure of the complexes formed in the reac... more The stoichiometry, stability constants and solution structure of the complexes formed in the reaction of tripeptides Sar-His-His (L1) and Sar-Gly-His (L2) with Cu(II) ion has been studied at 25±0.01oC and an ionic strength 0.15M (NaCl). Protonation and complex-formation constants have been determined potentiometrically. The structures of the species formed in solution are discussed on the basis of nuclear magnetic resonance and ultraviolet-visible spectrophotometry data. Molecular mechanics was used to investigate the possible structures. The Cu(II) plasma mobilization ability of tripeptides were evaluated using a computer model of blood plasma (ECCLES). Partition coefficients and dermal absorption results for all different modes will be discussed.
Complex-formation equilibria of the tripeptide Sar-His-Lys (L1), Sar-Lys-His (L2) and Sar-His-His... more Complex-formation equilibria of the tripeptide Sar-His-Lys (L1), Sar-Lys-His (L2) and Sar-His-His (L3) with the Cu(II) ion has been studied in aqueous solution, at 25±0.01oC and an ionic strength 0.15M (NaCl). Protonation and complex-formation constants have been potentiometrically determined. The structures of the formed complexes in solution species are discussed on the basis of nuclear magnetic resonance and ultraviolet-visible spectrophotometry data of solutions containing each of tripeptides with Cu(II). Molecular mechanics was used to investigate the possible structures. Plasma mobilization ability of Cu(II) tripeptide has been evaluated using a computer model of blood plasma (ECCLES) was used to assess the speciation in vivo of the copper complexes. The participation of two amide nitrogens in complex-formation is suggested for the metal ion, while no evidence supports the participation of the Ɛ-NH2 side groups of Lys residues in coordination.
Journal of Inorganic Biochemistry, 2015
ABSTRACT In the emerging issue of enhanced multi-resistant properties in infectious pathogens, ne... more ABSTRACT In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (S. aureus, B. subtilis, B. cereus) and negative (E. coli, P. aeruginosa, X. campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that its bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol–gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology.
Bioinorganic chemistry and applications, 2014
The thermodynamic equilibria of nickel(II) with N,N'-di(aminoethylene)-2,6-pyridinedicarbonyl... more The thermodynamic equilibria of nickel(II) with N,N'-di(aminoethylene)-2,6-pyridinedicarbonylamine (L1), Bis-(N,N-dimethylethyl)-2,6-pyridinedicarboxamide (L2), and N,N'-bis[2(2-pyridyl)-methyl]pyridine-2,6-dicarboxamide (L3) have been studied at 25°C and an ionic strength of 0.15 mol dm(-3) by glass electrode potentiometry. The protonation and formation constants added to blood plasma model predict that Cu(II) competes effectively against Ni(II), Zn(II), and Ca(II) for these ligands in vivo.
Journal of computer-aided molecular design, 2001
Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2) an... more Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2) and Del-CC (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-Gly-Asn-NH2) are adipokinetic hormones, isolated from the corpora cardiaca of different insect species. These hormones regulate energy metabolism during flight and so are intimately involved in an insect's mobility. Secondary structural elements of these peptides and the N7 analogue, [N7]-Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asn-Trp-NH2), have been determined in dimethylsulfoxide solution using NMR restrained molecular mechanic simulations. The neuropeptides were all found to have an extended structure for the first 4 residues and a beta-turn between residues 4-8. For Tem-HrTH and Del-CC, asparagine (N7) which is postulated to be involved in receptor binding and/or activation, projects outward form the beta-turn. Mem-CC does not have an asparagine at position 7 while, for [N7]-Mem-CC, the N7 sidechain folds inside the beta-turn preventing its in...
![Research paper thumbnail of Chromium-cage complex as contrast agent in MR imaging—Biodistribution studies of the [57Co]cobalt analogue](https://attachments.academia-assets.com/69854124/thumbnails/1.jpg)
](International Journal of Radiation Applications and Instrumentation. Part B. Nuclear Medicine and Biology, 1991
The synthesis and T, and T, relaxivities of the Cr(IIIHNH,)-Sarrcage complex is reported. An oute... more The synthesis and T, and T, relaxivities of the Cr(IIIHNH,)-Sarrcage complex is reported. An outer-sphere relaxation mechanism is postulated for the relaxivity of the complex. Tissue distribution studies in mice using a ["Colcobalt analogue as a radioactive tracer showed that the complex is excreted rapidly in the urine. Some renal uptake of the complex is seen. Appreciable uptake of labelled cage complex was observed in 3-methylcholanthrene induced murine rhabdomyosarcoma.
Journal of the Chemical Society, Dalton Transactions, 1989
ABSTRACT Zinc(II), calcium(II), and magnesium(II) complexes of 3,6,9,12-tetra-azatetradecanedioic... more ABSTRACT Zinc(II), calcium(II), and magnesium(II) complexes of 3,6,9,12-tetra-azatetradecanedioic acid and 3,6,9-triazaundecanedioic acid have been studied at 25 °C and an ionic strength of 0.15 mol dm–3 NaCl, using glass-electrode potentiometry. N.m.r. spectroscopy has been used to rationalize the data in terms of solution structures. Computer simulation has been used to predict the effect of the ligands on the blood plasma metal-ion distribution in vivo.
PeerJ
Background Neuropeptides exert their activity through binding to G protein-coupled receptors (GPC... more Background Neuropeptides exert their activity through binding to G protein-coupled receptors (GPCRs). GPCRs are well-known drug targets in the pharmaceutical industry and are currently discussed as targets to control pest insects. Here, we investigate the neuropeptide adipokinetic hormone (AKH) system of the desert locust Schistocerca gregaria. The desert locust is known for its high reproduction, and for forming devastating swarms consisting of billions of individual insects. It is also known that S. gregaria produces three different AKHs as ligands but has only one AKH receptor (AKHR). The AKH system is known to be essential for metabolic regulation, which is necessary for reproduction and flight activity. Methods Nuclear magnetic resonance techniques (NMR) in a dodecylphosphocholin (DPC) micelle solution were used to determine the structure of the three AKHs. The primary sequence of the S. gregaria AKHR was used to construct a 3D molecular model. Next, the three AKHs were individ...
Background. Neuropeptides exert their activity through binding to G-protein coupled receptors (GP... more Background. Neuropeptides exert their activity through binding to G-protein coupled receptors (GPCRs). GPCRs are well-known drug targets in the pharmaceutical industry and are currently discussed as targets to control pest insects. Here we investigate the neuropeptide adipokinetic hormone (AKH) system of the desert locust Schistocerca gregaria. The desert locust is known for its high reproduction, and for forming devastating swarms consisting of billions of individual insects. It is also known that S. gregaria produces three different AKHs as ligands but has only one AKH receptor. The AKH system is known to be essential for metabolic regulation, which is necessary for reproduction and flight activity. Methods. Nuclear magnetic resonance techniques (NMR) in a dodecylphosphocholin (DPC) micelle solution were used to determine the structure of the three AKHs. The primary sequence of the S. gregaria AKH receptor (AKHR) was used to construct a 3D molecular model. Next, the 3 AKHs were in...
Journal of neurochemistry, 2018
Alzheimer's disease (AD) belongs to one of the most multifactorial, complex and heterogeneous... more Alzheimer's disease (AD) belongs to one of the most multifactorial, complex and heterogeneous morbidity-leading disorders. Despite the extensive research in the field, AD pathogenesis is still at some extend obscure. Mechanisms linking AD with certain comorbidities, namely diabetes mellitus, obesity and dyslipidemia, are increasingly gaining importance, mainly because of their potential role in promoting AD development and exacerbation. Their exact cognitive impairment trajectories, however, remain to be fully elucidated. The current review aims to offer a clear and comprehensive description of the state-of-the-art approaches focused on generating in-depth knowledge regarding the overlapping pathology of AD and its concomitant ailments. Thorough understanding of associated alterations on a number of molecular, metabolic and hormonal pathways, will contribute to the further development of novel and integrated theranostics, as well as targeted interventions that may be beneficial ...
Data in brief, 2017
The data presented in this article are related to the publication "Interaction of the red pi... more The data presented in this article are related to the publication "Interaction of the red pigment-concentrating hormone of the crustacean Daphnia pulex, with its cognate receptor, Dappu-RPCHR: A nuclear magnetic resonance and modeling study" (Jackson et al., 2017) [1]. This article contains the data for homology modeling of the red pigment-concentrating hormone (RPCH) receptor of the water flea, Daphnia pulex (Dappu-RPCHR), which was constructed from its primary sequence. This is the first 3D model of a crustacean G-protein coupled receptor. Docking of the agonist, pGlu-Val-Asn-Phe-Ser-Thr-Ser-Trp amide (Dappu-RPCH), was used to find a binding pocket on the receptor and compared to the binding pocket of the adipokinetic hormone (AKH) receptor from the malaria mosquito. Data for the receptor, with and without loop refinement, together with the docked agonist, are presented.
Journal of Inorganic and Nuclear Chemistry
Journal of inorganic biochemistry, Nov 22, 2017
The advent of biodegradable nanomaterials with enhanced antibacterial activity stands as a challe... more The advent of biodegradable nanomaterials with enhanced antibacterial activity stands as a challenge to the global research community. In an attempt to pursue the development of novel antibacterial medicinal nanotechnology, we herein a) synthesized ionic-gelated chitosan nanoparticles, b) compared and evaluated the antibacterial activity of essential oils extracted from nine different herbs (Greek origin) and their combinations with a well-defined antibacterial Zn(II)-Schiff base compound, and c) encapsulated the most effective hybrid combination of Zn(II)-essential oils inside the chitosan matrix, thereby targeting well-formulated nanoparticles of distinct biological impact. The empty and loaded chitosan nanoparticles were physicochemically characterized by FT-IR, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), with the entrapment and drug release studies being conducted through UV-Visible and atomic absorption techniques. The antimicrobial properties of the n...
AIP Conference Proceedings, 2007
Knowledge of the chemical complexes (speciation) in urine can be extremely important in evaluatin... more Knowledge of the chemical complexes (speciation) in urine can be extremely important in evaluating the risk of crystallization of stone forming salts. In order to determine the speciation, a database of thermodynamic constants for the wide variety of complexes that ...
Journal of Nuclear Medicine, Feb 1, 1996
plex biological fluids. In this article, we describe the chemical speciation of Ga(III) and Gd(II... more plex biological fluids. In this article, we describe the chemical speciation of Ga(III) and Gd(III), two metal ions commonly used to prepare imaging agents and MRI contrast agents respectively. We hope to show how a knowledge of chemical speciation can help to explain existing clinical data and how it can be used in the design of new and more effective agents. ThEORYAND METhODOLOGY Metal Ion Speciation Speciation modeling ofblood plasma was pioneered by Pemn in a series of papers (1). At the same time Sillen (2), Morel (3), Martell (4) and others worked on natural waters and urine. These early models were restricted to one or two metal ions with a limited number of ligands. The development of faster computers with larger memories enabled these early models to be expanded into multicomponent systems. In the blood model developed by May et al. (5), 7 metal ions and 40 ligands were considered simulta neously. An essential process in the development ofany speciation model is to define a series of chemical equilibria which represent the system under investigation. In defining the equilibria all the chemical species involved and the equilibrium constants for the reactions have to be specified (Eq. 1). This is the area of greatest difficulty in speciation modelling as accurate equilibrium constants are not always available. Indeed, in some cases, all the possible equilibria have not been identified. Si â€" 13j @ X@((t.J), Metal chelate ions are commonly used in medical diagnostic imag ing as MRI contrast or imaging agents. The efficacy of these metals depends on their in vivo behavior, which in turn depends on their in vivo speciation. Methods: A computer model has been used to simulate the speciation of Ga3@ and Gd3@ in blood plasma. The model has been tested against known clinical data and then used to investigate Ga3@ uptake by tumor cells. The iatrogenic effect of a gadopentetic acid enhanced MRI scan upon the biodistilbution of 67Gacitratehas also beencalculated. Results:The speciationof @3± calculated using the computer model is concordant with clinical data. The results support transfernn mediated uptake of Ga3@ by tumor cells but also account for GaQII)biodistribution observed in hypotransfemnemicsubjects. Ina study of the effect of gadopentetic acidupon67Gagalliumcitrate,neitherresidual DTPA nor [Gd(DTPA)J2 cause signfficant changes in the speciation of Ga(III).The calculations show that dissociation of 4% of the admin istered gadopentetic acid results in the formation of a mixed, Gd(III) and Ga(III),metal transfernn complex and a 100-fold increase in the concentration of [Ga(OH)@J.Conclusion: Computer simulation is a valuable tool which can be used to explain/understand in vivo behavior of radioactive metal ions.
J Coord Chem, 1989
... ethane; ma1 = malonato; R,-ati = bis(N-alkylbenzoylacetoneiminato); Et = ethyl; Ph = phenyl; ... more ... ethane; ma1 = malonato; R,-ati = bis(N-alkylbenzoylacetoneiminato); Et = ethyl; Ph = phenyl; Bz = benzoyl; Pn-Bu, = iric-(n-butyl-phosphine); ox = oxalato; acac = acetylacetonato; py = pyridine; n-Pr = n-propyl; diars = Nyholm's diarsine; dmso ... M. Schumann and H. Elias, Inorg. ...
Polyhedron, 1991
ABSTRACT A novel copper(II) diaminodiamido complex is presented in which the 5,5,5-membered chela... more ABSTRACT A novel copper(II) diaminodiamido complex is presented in which the 5,5,5-membered chelate is more stable than the 5,6,5-membered chelate analogue.
Spectroscopy Letters, 1988
... METAL(I1) BIS(AQU0) COMPLEXES OF 8-HYDROXYQUINOLINE Carola Engelter, Graham E Jackson, Cheryl... more ... METAL(I1) BIS(AQU0) COMPLEXES OF 8-HYDROXYQUINOLINE Carola Engelter, Graham E Jackson, Cheryl L Knight, and David A Thornton ... Vogel A, A Textbook of Practical Organic Chemistry, 3rd ed. Longmans, London and New York, 1967, p. 830. Merritt L L, Anal. ...
Journal of Coordination Chemistry, 1989
Deuteration of 8-aminoquinoline (aq) at the amino groups and comparison of the infrared spectrum ... more Deuteration of 8-aminoquinoline (aq) at the amino groups and comparison of the infrared spectrum of aq with those of aniline and quinoline enables reliable assignments to be proposed for the amino stretching and bending modes and the internal modes of the aminoquinoline rings. The spectra of the tris(8-aminoquinoline) complexes of iron, cobalt and nickel perchlorates have been examined over the
The stoichiometry, stability constants and solution structure of the complexes formed in the reac... more The stoichiometry, stability constants and solution structure of the complexes formed in the reaction of tripeptides Sar-His-His (L1) and Sar-Gly-His (L2) with Cu(II) ion has been studied at 25±0.01oC and an ionic strength 0.15M (NaCl). Protonation and complex-formation constants have been determined potentiometrically. The structures of the species formed in solution are discussed on the basis of nuclear magnetic resonance and ultraviolet-visible spectrophotometry data. Molecular mechanics was used to investigate the possible structures. The Cu(II) plasma mobilization ability of tripeptides were evaluated using a computer model of blood plasma (ECCLES). Partition coefficients and dermal absorption results for all different modes will be discussed.
Complex-formation equilibria of the tripeptide Sar-His-Lys (L1), Sar-Lys-His (L2) and Sar-His-His... more Complex-formation equilibria of the tripeptide Sar-His-Lys (L1), Sar-Lys-His (L2) and Sar-His-His (L3) with the Cu(II) ion has been studied in aqueous solution, at 25±0.01oC and an ionic strength 0.15M (NaCl). Protonation and complex-formation constants have been potentiometrically determined. The structures of the formed complexes in solution species are discussed on the basis of nuclear magnetic resonance and ultraviolet-visible spectrophotometry data of solutions containing each of tripeptides with Cu(II). Molecular mechanics was used to investigate the possible structures. Plasma mobilization ability of Cu(II) tripeptide has been evaluated using a computer model of blood plasma (ECCLES) was used to assess the speciation in vivo of the copper complexes. The participation of two amide nitrogens in complex-formation is suggested for the metal ion, while no evidence supports the participation of the Ɛ-NH2 side groups of Lys residues in coordination.
Journal of Inorganic Biochemistry, 2015
ABSTRACT In the emerging issue of enhanced multi-resistant properties in infectious pathogens, ne... more ABSTRACT In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (S. aureus, B. subtilis, B. cereus) and negative (E. coli, P. aeruginosa, X. campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that its bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol–gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology.
Bioinorganic chemistry and applications, 2014
The thermodynamic equilibria of nickel(II) with N,N'-di(aminoethylene)-2,6-pyridinedicarbonyl... more The thermodynamic equilibria of nickel(II) with N,N'-di(aminoethylene)-2,6-pyridinedicarbonylamine (L1), Bis-(N,N-dimethylethyl)-2,6-pyridinedicarboxamide (L2), and N,N'-bis[2(2-pyridyl)-methyl]pyridine-2,6-dicarboxamide (L3) have been studied at 25°C and an ionic strength of 0.15 mol dm(-3) by glass electrode potentiometry. The protonation and formation constants added to blood plasma model predict that Cu(II) competes effectively against Ni(II), Zn(II), and Ca(II) for these ligands in vivo.
Journal of computer-aided molecular design, 2001
Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2) an... more Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2), Tem-HrTH (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-NH2) and Del-CC (pGlu-Leu-Asn-Phe-Ser-Pro-Asn-Trp-Gly-Asn-NH2) are adipokinetic hormones, isolated from the corpora cardiaca of different insect species. These hormones regulate energy metabolism during flight and so are intimately involved in an insect's mobility. Secondary structural elements of these peptides and the N7 analogue, [N7]-Mem-CC (pGlu-Leu-Asn-Tyr-Ser-Pro-Asn-Trp-NH2), have been determined in dimethylsulfoxide solution using NMR restrained molecular mechanic simulations. The neuropeptides were all found to have an extended structure for the first 4 residues and a beta-turn between residues 4-8. For Tem-HrTH and Del-CC, asparagine (N7) which is postulated to be involved in receptor binding and/or activation, projects outward form the beta-turn. Mem-CC does not have an asparagine at position 7 while, for [N7]-Mem-CC, the N7 sidechain folds inside the beta-turn preventing its in...
International Journal of Radiation Applications and Instrumentation. Part B. Nuclear Medicine and Biology, 1991
The synthesis and T, and T, relaxivities of the Cr(IIIHNH,)-Sarrcage complex is reported. An oute... more The synthesis and T, and T, relaxivities of the Cr(IIIHNH,)-Sarrcage complex is reported. An outer-sphere relaxation mechanism is postulated for the relaxivity of the complex. Tissue distribution studies in mice using a ["Colcobalt analogue as a radioactive tracer showed that the complex is excreted rapidly in the urine. Some renal uptake of the complex is seen. Appreciable uptake of labelled cage complex was observed in 3-methylcholanthrene induced murine rhabdomyosarcoma.
Journal of the Chemical Society, Dalton Transactions, 1989
ABSTRACT Zinc(II), calcium(II), and magnesium(II) complexes of 3,6,9,12-tetra-azatetradecanedioic... more ABSTRACT Zinc(II), calcium(II), and magnesium(II) complexes of 3,6,9,12-tetra-azatetradecanedioic acid and 3,6,9-triazaundecanedioic acid have been studied at 25 °C and an ionic strength of 0.15 mol dm–3 NaCl, using glass-electrode potentiometry. N.m.r. spectroscopy has been used to rationalize the data in terms of solution structures. Computer simulation has been used to predict the effect of the ligands on the blood plasma metal-ion distribution in vivo.