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Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath W. Ecroyd, Shaun D. Roman, Robert J. Aitken
Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath W. Ecroyd, Shaun D. Roman, Robert J. Aitken
Faculty of Science - Papers (Archive)
The capacitation of mammalian spermatozoa involves the activation of a cAMP-mediated signal transduction pathway that drives tyrosine phosphorylation via mechanisms that are unique to this cell type. Controversy surrounds the impact of extracellular calcium on this process, with positive and negative effects being recorded in independent publications. We clearly demonstrate that the presence of calcium in the external medium decreases tyrosine phosphorylation in both human and mouse spermatozoa. Under these conditions, a rise in intracellular pH was recorded, however, this event was not responsible for the observed changes in phosphotyrosine expression. Rather, the impact of calcium on tyrosine phosphorylation in …
On The Transferability Of The Spcal Water Model To Biomolecular Simulation, Alice Glaettli, Chris Oostenbrink, Xavier Daura, Daan Geerke, Haibo Yu, Wilfred Van Gunsteren
On The Transferability Of The Spcal Water Model To Biomolecular Simulation, Alice Glaettli, Chris Oostenbrink, Xavier Daura, Daan Geerke, Haibo Yu, Wilfred Van Gunsteren
Faculty of Science - Papers (Archive)
We investigated the performance of the recently developed SPC/L model for liquid water, as a pure liquid, in binary mixtures with DMSO, and as a solvent model in a peptide folding simulation. Additionally, in order to test the compatibility with the GROMOS biomolecular force field, free energies of hydration of a set of representative compounds were computed. The results are compared to those for the well established SPC water model, which is generally used as a solvent model in conjunction with the GROMOS force field already for more than two decades. It turns out that as a pure liquid and …
Protecting Group Effects On The Efficiency Of The Ruthenium-Catalyzed Alder-Ene Reaction, Joseph Hartley, Stephen G. Pyne
Protecting Group Effects On The Efficiency Of The Ruthenium-Catalyzed Alder-Ene Reaction, Joseph Hartley, Stephen G. Pyne
Faculty of Science - Papers (Archive)
The efficiency of the ruthenium-catalysed Alder-ene reaction of hydroxy alkenes depends heavily on the nature of the O-protecting groups employed as well as the length of the carbon spacer between the hydroxy and alkene group.
Compartmentalization Of Prion Isoforms Within The Reproductive Tract Of The Ram, Heath W. Ecroyd, Pierre Sarradin, Jean-Louis Dacheux, Jean-Luc Gatti
Compartmentalization Of Prion Isoforms Within The Reproductive Tract Of The Ram, Heath W. Ecroyd, Pierre Sarradin, Jean-Louis Dacheux, Jean-Luc Gatti
Faculty of Science - Papers (Archive)
Cellular prion protein (Prp(C)) is a glycoprotein usually associated with membranes via its glycosylphosphatidylinositol (GPI) anchor. The trans-conformational form of this protein (Prp(SC)) is the suggested agent responsible for transmissible neurodegenerative spongiform encephalopathies. This protein has been shown on sperm and in the reproductive fluids of males. Antibodies directed against the C-terminal sequence near the GPI-anchor site, an N-terminal sequence, and against the whole protein showed that the Prp isoforms were compartmentalized within the reproductive tract of the ram. Immunoblotting with the three antibodies showed that the complete protein and both N- and C-terminally truncated and glycosylated isoforms are present …
The Development Of Signal Transduction Pathways During Epididymal Maturation Is Calcium Dependent, Heath W. Ecroyd, Kelly Asquith, Russell C. Jones, Robert J. Aitken
The Development Of Signal Transduction Pathways During Epididymal Maturation Is Calcium Dependent, Heath W. Ecroyd, Kelly Asquith, Russell C. Jones, Robert J. Aitken
Faculty of Science - Papers (Archive)
Capacitation has been correlated with the activation of a cAMP-PKA-dependent signaling pathway leading to protein tyrosine phosphorylation. The ability to exhibit this response to cAMP matures during epididymal maturation in concert with the ability of the sperrnatozoa to capacitate. In this study, we have addressed the mechanisms by which spermatozoa gain the potential to activate this signaling pathway during epididymal maturation. In a modified Tyrode's medium containing 1.7 mM calcium, caput spermatozoa had significantly higher [Ca2+](i) than caudal cells and could not tyrosine phosphorylate in response to cAMP. However, in calcium-depleted medium both caput and caudal cells could exhibit a …
Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren
Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren
Faculty of Science - Papers (Archive)
The properties of two improved versions of charge-on-spring �COS� polarizable water models (COS/G2 and COS/G3) that explicitly include nonadditive polarization effects are reported. In COS models, the polarization is represented via a self-consistently induced dipole moment consisting of a pair of separated charges. A previous polarizable water model (COS/B2), upon which the improved versions are based, was developed by Yu, Hansson, and van Gunsteren �J. Chem. Phys. 118, 221 �2003��. To improve the COS/B2 model, which overestimated the dielectric permittivity, one additional virtual atomic site was used to reproduce the water monomer quadrupole moments besides the water monomer dipole moment …
Molecular Dynamics Simulations Of Peptides Containing An Unnatural Amino Acid: Dimerization, Folding, And Protein Binding, Haibo Yu, Xavier Daura, Wilfred Van Gunsteren
Molecular Dynamics Simulations Of Peptides Containing An Unnatural Amino Acid: Dimerization, Folding, And Protein Binding, Haibo Yu, Xavier Daura, Wilfred Van Gunsteren
Faculty of Science - Papers (Archive)
We have performed molecular dynamics (MD) simulations to study the dimerization, folding, and binding to a protein of peptides containing an unnatural amino acid. NMR studies have shown that the substitution of one residue in a tripeptide β-strand by the unnatural amino acid Hao (5-HO2CCONH-2-MeO-C6H3-CO-NHNH2) modifies the conformational flexibility of the β-strand and the hydrogen-bonding properties of its two edges: The number of hydrogen-bond donors and acceptors increases at one edge, whereas at the other, they are sterically hindered. In simulations in chloroform, the Hao-containing peptide 9 (i-PrCO-Phe-Hao-Val-NHBu) forms a β-sheet–like hydrogen-bonded dimer, in good agreement with the available experimental …
Processes Controlling Metal Transport And Retention As Metal-Contaminated Groundwaters Efflux Through Estuarine Sediments, Stuart L. Simpson, Edward J. Maher, Dianne F. Jolley
Processes Controlling Metal Transport And Retention As Metal-Contaminated Groundwaters Efflux Through Estuarine Sediments, Stuart L. Simpson, Edward J. Maher, Dianne F. Jolley
Faculty of Science - Papers (Archive)
Factors affecting the transport and retention of Cd, Cr, Cu, Ni, Pb and Zn in acidic groundwaters as they pass through estuarine sediments were investigated using column experiments. Acidic groundwaters caused the rapid dissolution of iron sulfide (AVS) and other iron and manganese phases from sediments that are important for metal binding and buffering. Metal breakthrough to overlying water occurred in the order of Ni>Zn>Cd>>Cu>>Cr/Pb. Metal transport increased as the sediment permeability increased, reflecting the low resistance to flow caused by larger sand-sized particles and the decreased abundance of metal adsorption sites on these materials. Metal …
Selenium Accumulation In The Cockle Anadara Trapezia, Dianne F. Jolley, William A. Maher, Jennelle Kyd
Selenium Accumulation In The Cockle Anadara Trapezia, Dianne F. Jolley, William A. Maher, Jennelle Kyd
Faculty of Science - Papers (Archive)
An extensive study on Se accumulation in a population of Anadara trapezia from a marine lake is reported. The effects of organism mass, gender, reproductive cycle, and season on Se accumulation and tissue distribution were investigated. Analyses showed that gender and reproductive cycle had no significant effect on Se accumulation. A. trapezia showed a strong positive correlation between Se burden and tissue mass. Constant Se concentrations were observed within individual populations but varied spatially with sediment Se concentrations. Se concentrations in tissues decreased from gills>gonad/intestineOmantleO muscleOfoot, which remained constant over 12 months, however, significantly lower concentrations were observed in …
Asymmetric Synthesis Of (+)-1-Epiaustraline And Attempted Synthesis Of Australine, Minyan Tang, Stephen G. Pyne
Asymmetric Synthesis Of (+)-1-Epiaustraline And Attempted Synthesis Of Australine, Minyan Tang, Stephen G. Pyne
Faculty of Science - Papers (Archive)
A diastereoselective synthesis of the pyrrolizidine alkaloid, (+)-1-epiaustraline has been achieved via a diastereoselective syn-dihydroxylation of a pyrrolo[1,2-c]oxazol-3-one precursor that was readily prepared by a RCM reaction. Attempts to extend this methodology to the synthesis of australine were not successful since the final pyrrolidine ring closure to produce the desired pyrrolizidine of the target molecule was not productive.
Phytochemical Studies On Stemona Burkillii Prain: Two New Dihydrostemofoline Alkaloids, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Wilford Lie, Alison T. Ung, Kritchaya Issakul, Auntika Sawatwanich, Damrat Supyen, Chaiwat Jatisatienr
Phytochemical Studies On Stemona Burkillii Prain: Two New Dihydrostemofoline Alkaloids, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Wilford Lie, Alison T. Ung, Kritchaya Issakul, Auntika Sawatwanich, Damrat Supyen, Chaiwat Jatisatienr
Faculty of Science - Papers (Archive)
Two new dihydrostemofoline alkaloids, 11(S),12(R)-dihydrostemofoline (3) and stemoburkilline (4), along with stemofoline (1) and 2’-hydroxystemofoline (2) have been isolated from a root extract of Stemona burkillii Prain. The structure and relative configuration of (3) have been determined via spectroscopic data and from comparison with synthetic 11(S),12(S)-dihydrostemofoline (5). The configuration of the exo-cyclic alkene group in (4) is tentively assigned as (E) based upon mechanistic considerations.
Asymmetric Synthesis Of (-)-Swainsonine, Karl Lindsay, Stephen G. Pyne
Asymmetric Synthesis Of (-)-Swainsonine, Karl Lindsay, Stephen G. Pyne
Faculty of Science - Papers (Archive)
This paper describes a new synthesis of (-)-swainsonine via the ring-closing metathesis reaction of a substituted 3-allyl-4-vinyl-2-oxazolindinone and subsequent diastereoselective syn-dihydroxylation of the resulting pyrrolo[1,2-c]oxazol-3-one.
Phytochemical And Larvicidal Studies On Stemona Curtisii: Structure Of A New Pyriodo[1,2-A]Azepine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Chaiwat Jatisatienr, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White
Phytochemical And Larvicidal Studies On Stemona Curtisii: Structure Of A New Pyriodo[1,2-A]Azepine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Chaiwat Jatisatienr, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White
Faculty of Science - Papers (Archive)
A new pentacyclic Stemona alkaloid, stemocurtisinol (3), with a pyrido[1,2-a]azepine A,B-ring system, and the known pyrrolo[1,2-a]azepine alkaloid oxyprotostemonine (4) have been isolated from a root extract of S. curtisii. The structure and relative stereochemistry of stemocurtisinol was determined by spectral data interpretation and X-ray crystallography. This compound is a diastereoisomer of oxystemokerrin and has the opposite configuration at C-4 and C-19. The individual alkaloid components showed significant larvicidal activity (IC50 4−39 ppm) on mosquito larvae (Anopheles minimus HO).
Synthesis Of (+)-(1r,2s,9s,9ar)-Octahydro-1h-Pyrrolo-[1,2-A]Azepine-1,2,9-Triol: A Potential Glycosidase Inhibitor, Karl B. Lindsay, Stephen G. Pyne
Synthesis Of (+)-(1r,2s,9s,9ar)-Octahydro-1h-Pyrrolo-[1,2-A]Azepine-1,2,9-Triol: A Potential Glycosidase Inhibitor, Karl B. Lindsay, Stephen G. Pyne
Faculty of Science - Papers (Archive)
The title compound was prepared as a potential glycosidase inhibitor. Key steps in the synthesis are vinyl epoxide aminolysis, ring-closing metathesis, cis-dihydroxylation and then ring closure.
Asymmetric Synthesis Of Polyfunctionalized Pyrrolidines And Related Alkaloids, Stephen G. Pyne, Andrew S. Davis, Nicole Gates, Joseph Hartley, Karl Lindsay, Theeraphan Machan, Minyan Tang
Asymmetric Synthesis Of Polyfunctionalized Pyrrolidines And Related Alkaloids, Stephen G. Pyne, Andrew S. Davis, Nicole Gates, Joseph Hartley, Karl Lindsay, Theeraphan Machan, Minyan Tang
Faculty of Science - Papers (Archive)
This account describes our recent studies on the development of a general method of preparing polyfunctionalized pyrrolidine, indolizidine, pyrrolizidine and pyrrolo[1,2-a]azepines and their related alkaloids.
Plasminogen Binding By Group A Streptococcal Isolates From A Tropical Region With Hyperendemic Streptococcal Skin Infection And A High Incidence Of Invasive Infection, F. C. Mckay, Jason D. Mcarthur, Martina L. Sanderson-Smith, S. Gardam, B. J. Currie, K. S. Sriprakash, P. K. Fagan, R. J. Towers, M. R. Batzloff, G. S. Chhatwal, Marie Ranson, Mark J. Walker
Plasminogen Binding By Group A Streptococcal Isolates From A Tropical Region With Hyperendemic Streptococcal Skin Infection And A High Incidence Of Invasive Infection, F. C. Mckay, Jason D. Mcarthur, Martina L. Sanderson-Smith, S. Gardam, B. J. Currie, K. S. Sriprakash, P. K. Fagan, R. J. Towers, M. R. Batzloff, G. S. Chhatwal, Marie Ranson, Mark J. Walker
Faculty of Science - Papers (Archive)
Reports of resurgence in invasive group A streptococcal (GAS) infections come mainly from affluent populations with infrequent exposure to GAS. In the tropical Northern Territory (NT) of Australia, high incidence of invasive GAS disease is secondary to endemic skin infection; serotype M1 clones are rare in invasive infection; the diversity and level of exposure to GAS strains is high and no particular strains dominate. Expression of a plasminogen-binding group A streptococcal M-like protein (PAM) has been associated with skin infection in isolates elsewhere (Bessen, D., C.M. Sotir, T.M. Readdy, and S.K. Hollingshead.1996. J. Infect. Dis. 173:896-900) and subversion of the …
Poly(2-Alkylacrylic Acid) Polymers Deliver Molecules To The Cytosol By Ph-Sensitive Disruption Of Endosomal Vesicles, Rachel A. Jones, C. Y. Cheung, F. E. Black, J. K. Zia, P. S. Stayton, A. S. Hoffman, Mark R. Wilson
Poly(2-Alkylacrylic Acid) Polymers Deliver Molecules To The Cytosol By Ph-Sensitive Disruption Of Endosomal Vesicles, Rachel A. Jones, C. Y. Cheung, F. E. Black, J. K. Zia, P. S. Stayton, A. S. Hoffman, Mark R. Wilson
Faculty of Science - Papers (Archive)
The permeability barrier posed by cell membranes represents a challenge for the delivery of hydrophilic molecules into cells. We previously proposed that poly(2- alkylacrylic acid)s are endocytosed by cells into acidified vesicles and are there triggered by low pH to disrupt membranes and release the contents of endosomes/lysosomes to the cytosol. If this hypothesis is correct, these polymers could be valuable in drug delivery applications. This report provides functional comparisons of a family of three poly(2-alkylacrylic acid)s. Poly(2-propylacrylic acid) (PPAA), poly(2-ethylacrylic acid) (PEAA), and poly(2-methylacrylic acid) (PMAA) were compared in red blood cell haemolysis assays and in a lipoplex gene …
Novel Pharmacophore Based Methods Reveal Gossypol As A Reverse Transcriptase Inhibitor, Paul A. Keller, C. Birch, S. P. Leach, D. Tyssen, R. Griffith
Novel Pharmacophore Based Methods Reveal Gossypol As A Reverse Transcriptase Inhibitor, Paul A. Keller, C. Birch, S. P. Leach, D. Tyssen, R. Griffith
Faculty of Science - Papers (Archive)
In a program to identify new structural entities for the inhibition of the HIV-1 reverse transcriptase (RT) enzyme via database searching, a series of RT pharmacophores were developed. By utilising a novel filtering technique, the National Cancer Institute database of compounds was scanned producing 15 compounds to be screened for activity. A notable inclusion was a series of gossypol derivatives. The testing of a series of compounds revealed the parent compound gossypol to be an HIV-1 reverse transcriptase inhibitor. These results suggest that at least part of its anti-HIV activity is due to gossypol targeting the non-nucleoside inhibitor binding pocket …
Probing Dna Selectivity Of Ruthenium Metallointercalators Using Esi Mass Spectrometry, Jennifer L. Beck, Rajesh Gupta, Thitima Urathamakul, Nyree L. Williamson, Margaret Sheil, Janice Aldrich-Wright, Stephen F. Ralph
Probing Dna Selectivity Of Ruthenium Metallointercalators Using Esi Mass Spectrometry, Jennifer L. Beck, Rajesh Gupta, Thitima Urathamakul, Nyree L. Williamson, Margaret Sheil, Janice Aldrich-Wright, Stephen F. Ralph
Faculty of Science - Papers (Archive)
ESI mass spectra show that up to five ruthenium molecules can bind non-covalently to double stranded 16mer DNA, and provide information on the relative affinity and DNA sequence selectivity of different ruthenium complexes.
Asymmetric Synthesis Of (-)-7-Epiaustraline And (+)-1,7-Diepiaustraline, Minyan Tang, Stephen G. Pyne
Asymmetric Synthesis Of (-)-7-Epiaustraline And (+)-1,7-Diepiaustraline, Minyan Tang, Stephen G. Pyne
Faculty of Science - Papers (Archive)
A diastereoselective and modular approach to the synthesis of the 3-hydroxymethyl-2,3,5,6,7,7a-hexahydro-1H-pyrrolizine-1,2,7-triol structure, characteristic of several natural pyrrolizidine natural products has been developed. This approach culminated in the synthesis of (-)-7-epiaustraline and (+)-1,7-diepiaustraline. The oxazolidinone group has been found to be a useful protecting group in the RCM reaction and, as part of a pyrrolo[1,2-c]oxazol-3-one ring system, has functioned as a stereo- and regio-directing group, in a key diastereoselective cis-dihydroxylation reaction and a regioselective nucleophilic ring-opening of a S,S-dioxo-dioxathiole.
Chemo-Enzymatic Synthesis Of (-)-Epipentenomycin I, Tawesin Klomklao, Stephen G. Pyne, Apiwat Baramee, Brian W. Skelton, Allan H. White
Chemo-Enzymatic Synthesis Of (-)-Epipentenomycin I, Tawesin Klomklao, Stephen G. Pyne, Apiwat Baramee, Brian W. Skelton, Allan H. White
Faculty of Science - Papers (Archive)
A chemo-enzymatic synthesis of (−)-epipentenomycin I is reported using a lipase-catalysed kinetic resolution of the racemic pentacyclic alcohol 8. Flash vacuum pyroloysis of (−)-8 so obtained gave (−)-(4R)-4-hydroxy-5-methylene-2-cyclopentenone. Epoxidation of this compound with dimethyldioxirane followed by hydrolytic ring-opening of the resulting epoxide gave (−)-epipentenomycin I.
The Prevention Of Preterm Labour – Corticotropin Releasing Hormone Type 1 Receptors As A Target For Drug Design And Development, Paul A. Keller, K. Kirkwood, J. Morgan, S. Westcott, A. Mccluskey
The Prevention Of Preterm Labour – Corticotropin Releasing Hormone Type 1 Receptors As A Target For Drug Design And Development, Paul A. Keller, K. Kirkwood, J. Morgan, S. Westcott, A. Mccluskey
Faculty of Science - Papers (Archive)
The role of the corticotropin releasing hormone in the onset of labour and the subsequent medicinal chemistry implications of CRH antagonists for the prevention of premature birth, and identification of the CRH type 1 receptor as the target for this drug design, are reviewed here.
Development Of A Simple, Self-Consistent Polarizable Model For Liquid Water, Haibo Yu, Tomas Hansson, Wilfred Van Gunsteren
Development Of A Simple, Self-Consistent Polarizable Model For Liquid Water, Haibo Yu, Tomas Hansson, Wilfred Van Gunsteren
Faculty of Science - Papers (Archive)
The charge-on-spring method is used to develop a rigid, three-site, polarizable water model, a noniterative and a self-consistent version. In this method, the polarizability is taken into account by a variable separation of charges on selected polarizable centers. One of the pair of polarization charges resides on a polarizable center, while the other one is treated as an additional particle attached to the polarizable center by a parabolic restraint potential. The separation is calculated in response to the instantaneous electric field. We parametrized two models which are based on noniterative and self-consistent versions of the method, respectively. We computed several …
Tyrosine Phosphorylation Of Hsp-90 During Mammalian Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken
Tyrosine Phosphorylation Of Hsp-90 During Mammalian Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken
Faculty of Science - Papers (Archive)
The process of sperm capacitation is correlated with activation of a signal transduction pathway leading to protein tyrosine phosphorylation. Whereas phosphotyrosine expression is an essential prerequisite for fertilization, the proteins that are phosphorylated during capacitation have not yet been identified. In the present study, we observed that a major target of this signaling pathway is the molecular chaperone protein, heat shock protein (HSP)-86, a member of the HSP-90 family of HSPs. We used cross-immunoprecipitation experiments to confirm the tyrosine phosphorylation of HSP-86, a process that is not inhibited by the ansamycin antibiotic, geldanamycin. The general significance of these findings was …
Endogenous Redox Activity In Mouse Spermatozoa And Its Role In Regulating The Tyrosine Phosphorylation Events Associated With Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken
Endogenous Redox Activity In Mouse Spermatozoa And Its Role In Regulating The Tyrosine Phosphorylation Events Associated With Sperm Capacitation, Heath W. Ecroyd, Russell C. Jones, Robert J. Aitken
Faculty of Science - Papers (Archive)
We investigated the role of endogenous redox activity in regulating the signal transduction pathway leading to tyrosine phosphorylation in mouse spermatozoa. Endogenous redox activity was monitored using a luminol-peroxidase chemiluminescent probe. Chemiluminescence increased in spermatozoa that were actively undergoing cAMP-mediated tyrosine phosphorylation events associated with capacitation and was inhibited in a dose-dependent manner by addition of catalase or diphenylene iodonium, both of which also inhibited tyrosine phosphorylation within the cell at points downstream of cAMP. Excluding bicarbonate from the incubation medium reduced the redox activity of sperm by 80-90% and dramatically reduced tyrosine phosphorylation. This study provides the first evidence …
Stemocurtisine, The First Pyrido[1,2-A]Azapine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White
Stemocurtisine, The First Pyrido[1,2-A]Azapine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White
Faculty of Science - Papers (Archive)
A new pentacyclic stemona alkaloid, stemocurtisine (2), with a novel pyrido[1,2-a]azapine A,B-ring system, has been isolated from a root extract of Stemona curtisii. The structure and relative stereochemistry was determined by spectral data interpretation and X-ray crystallography.
Evolution Of Chemical Contaminant And Toxicology Studies, Part 1 - An Overview, Dianne F. Jolley, Glennys A. O'Brien, Robert John Morrison
Evolution Of Chemical Contaminant And Toxicology Studies, Part 1 - An Overview, Dianne F. Jolley, Glennys A. O'Brien, Robert John Morrison
Faculty of Science - Papers (Archive)
The study of environmental chemical contaminants and their toxicological effects has changed dramatically over the last 50 years. Initially studies concentrated on trying to identify what contaminants were actually present and to develop quantitative methods to determine the concentrations (total) present. Health impacts were often investigated independently in medical research centres. With improving analytical techniques, studies of the speciation of contaminants began and the specific forms that were creating the major problems were gradually identified. Continuing improvements in analytical chemistry, together with a move towards more integrated and multidisciplinary research now sees chemists, biologists, toxicologists and health researchers working closely …
Evolution Of Chemical Contaminant And Toxicology Studies, Part 2- Case Studies Of Selenium And Arsenic, Glennys O'Brien, Dianne Jolley, Robert John Morrison
Evolution Of Chemical Contaminant And Toxicology Studies, Part 2- Case Studies Of Selenium And Arsenic, Glennys O'Brien, Dianne Jolley, Robert John Morrison
Faculty of Science - Papers (Archive)
As the second of a two part series discussing the evolution of the field of environmental toxicology, this paper presents two case studies: selenium and arsenic. Developments over several decades in the understanding of the behaviour of arsenic and selenium in different chemical forms in various compartments of the environment are discussed. Selenium was initially thought to be toxic, but later investigations showed it to be an essential micronutrient with a variety of biochemical functions, and, importantly, that there is a very narrow gap between the essential and the toxic body burden. Arsenic, on the other hand, has not yet …
Streptococcus Pyogenes Prtfii, But Not Sfbi, Sfbii Or Fbp54, Is Represented More Frequently Among Invasive-Disease Isolates Of Tropical Australia, A. Delvecchio, B. J. Currie, Jason D. Mcarthur, Mark J. Walker, K. S. Sriprakash
Streptococcus Pyogenes Prtfii, But Not Sfbi, Sfbii Or Fbp54, Is Represented More Frequently Among Invasive-Disease Isolates Of Tropical Australia, A. Delvecchio, B. J. Currie, Jason D. Mcarthur, Mark J. Walker, K. S. Sriprakash
Faculty of Science - Papers (Archive)
Streptococcus pyogenes (group A streptococcus) strains may express several distinct ®bronectinbinding proteins (FBPs) which are considered as major streptococcal adhesins. Of the FBPs, SfbI was shown in Šitro to promote internalization of the bacterium into host cells and has been implicated in persistence. In the tropical Northern Territory, where group A streptococcal infection is common, multiple genotypes of the organism were found among isolates from invasive disease cases and no dominant strains were observed. To determine whether any FBPs is associated with invasive disease propensity of S. pyogenes, we have screened streptococcal isolates from bacteraemic and necrotizing fasciitis patients and …
Synthesis Of Chiral Allylic Amines Via Palladium(0) Catalysed Allylations Of Allylic Carbonates With Chiral Sulfinamide Anions, Zemin Dong, Stephen G. Pyne
Synthesis Of Chiral Allylic Amines Via Palladium(0) Catalysed Allylations Of Allylic Carbonates With Chiral Sulfinamide Anions, Zemin Dong, Stephen G. Pyne
Faculty of Science - Papers (Archive)
The palladium(0) catalysed allylation reactions of allylic carbonates with chiral sulfinamide anions to give unstable allylic sulfinamide products are described. These products are readily converted to stable, chiral N-benzoyl or N-tosyl allylic amine derivatives with poor to modest enantiomeric purities (ee 23-41%).