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Full-Text Articles in Social and Behavioral Sciences
M Protein Mediated Plasminogen Binding Is Essential For The Virulence Of An Invasive Streptococcus Pyogenes Isolate, Martina L. Sanderson-Smith, K. Dinkla, J. N. Cole, Amanda J. Cork, P. G. Maamary, Jason D. Mcarthur, G. S. Chhatwal, Mark J. Walker
M Protein Mediated Plasminogen Binding Is Essential For The Virulence Of An Invasive Streptococcus Pyogenes Isolate, Martina L. Sanderson-Smith, K. Dinkla, J. N. Cole, Amanda J. Cork, P. G. Maamary, Jason D. Mcarthur, G. S. Chhatwal, Mark J. Walker
Faculty of Science - Papers (Archive)
The human protease plasmin plays a crucial role in the capacity of the group A streptococcus (Streptococus pyogenes; GAS) to initiate invasive disease. The GAS strain NS88.2 was isolated from a case of bacteremia from the Northern Territory of Australia, a region with high rates of GAS invasive disease. Mutagenesis of the NS88.2 plasminogen binding M protein Prp was undertaken to examine the contribution of plasminogen binding and cell surface plasmin acquisition to virulence. The isogenic mutant NS88.2prp was engineered whereby four amino acid residues critical for plasminogen binding were converted to alanine codons in the GAS genome sequence. The …
Allelic Variants Of Streptokinase From Streptococcus Pyogenes Display Functional Differences In Plasminogen Activation., Jason D. Mcarthur, F. C. Mckay, V. Ramachandran, P. Shyam, Amanda J. Cork, Martina L. Sanderson-Smith, J. N. Cole, U. Ringdahl, U. Sjobring, M. Ranson, Mark J. Walker
Allelic Variants Of Streptokinase From Streptococcus Pyogenes Display Functional Differences In Plasminogen Activation., Jason D. Mcarthur, F. C. Mckay, V. Ramachandran, P. Shyam, Amanda J. Cork, Martina L. Sanderson-Smith, J. N. Cole, U. Ringdahl, U. Sjobring, M. Ranson, Mark J. Walker
Faculty of Science - Papers (Archive)
A common mammalian defence mechanism employed to prevent systemic dissemination of invasive bacteria involves occlusion of local microvasculature and encapsulation of bacteria within fibrin networks. Acquisition of plasmin activity at the bacterial cell surface circumvents this defence mechanism allowing invasive disease initiation. To facilitate this process, S. pyogenes secrete streptokinase, a plasminogen activating protein. Streptokinase polymorphism exhibited by S. pyogenes isolates is well characterised. However, the functional differences displayed by these variants and the biological significance of this variation has not been elucidated. Phylogenetic analysis of ska sequences from 28 S. pyogenes isolates revealed two main sequence clusters (clusters 1 …
Opacity Factor Activity And Epithelial Cell Binding By The Serum Opacity Factor Protein Of Streptococcus Pyogenes Are Functionally Discrete, C. M. Gillen, H. S. Courtney, K. Schulze, M. Rohde, Mark R. Wilson, A. M. Timmer, C. A. Guzman, V. Nizet, G. S. Chhatwal, Mark J. Walker
Opacity Factor Activity And Epithelial Cell Binding By The Serum Opacity Factor Protein Of Streptococcus Pyogenes Are Functionally Discrete, C. M. Gillen, H. S. Courtney, K. Schulze, M. Rohde, Mark R. Wilson, A. M. Timmer, C. A. Guzman, V. Nizet, G. S. Chhatwal, Mark J. Walker
Faculty of Science - Papers (Archive)
Serum opacity factor (SOF) is a unique multifunctional virulence determinant expressed at the surface of Streptococcus pyogenes and has been shown to elicit protective immunity against GAS infection in a murine challenge model. SOF consists of two distinct domains with different binding capacities: an N-terminal domain that binds apolipoprotein AI and a C-terminal repeat domain that binds fibronectin and fibrinogen. The capacity of SOF to opacify serum by disrupting the structure of high density lipoproteins may preclude its use as a vaccine antigen in humans. This study generated mutant forms of recombinant SOF with reduced (100-fold) or abrogated opacity factor …
Uptake And Internalisation Of Copper By Three Marine Microalgae: Comparison Of Copper-Sensitive And Copper-Tolerant Species, Jacqueline L. Levy, Brad M. Angel, Jennifer L. Stauber, Wing L. Poon, Stuart L. Simpson, Shuk Han Cheng, Dianne F. Jolley
Uptake And Internalisation Of Copper By Three Marine Microalgae: Comparison Of Copper-Sensitive And Copper-Tolerant Species, Jacqueline L. Levy, Brad M. Angel, Jennifer L. Stauber, Wing L. Poon, Stuart L. Simpson, Shuk Han Cheng, Dianne F. Jolley
Faculty of Science - Papers (Archive)
Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 μg Cu L-1, compared to the green algae Tetraselmis sp. (72-h IC50 47 μg Cu L-1) and Dunaliella tertiolecta (72-h IC50 530 μg Cu L-1 …
Antimycobacterial Activity Of Cinnamate-Based Esters Of The Triterpenes Betulinic, Oleanolic And Ursolic Acids, Tanud Tanachatchairatana, John B. Bremner, Ratchanaporn Chokchaisiri, Apichart Suksamrarn
Antimycobacterial Activity Of Cinnamate-Based Esters Of The Triterpenes Betulinic, Oleanolic And Ursolic Acids, Tanud Tanachatchairatana, John B. Bremner, Ratchanaporn Chokchaisiri, Apichart Suksamrarn
Faculty of Science - Papers (Archive)
Betulinic acid, oleanolic acid and ursolic acid have been modified at the C-3 position to cinnamate-based esters and in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Ra has been determined. The results indicated that modification of the parent structures of betulinic acid, oleanolic acid and ursolic acid to the p-coumarate and, in the case of the latter two triterpenes, the ferulate ester analogues resulted in high antimycobacterial activity. Structure–activity relationships within the lupane, oleanane and ursane analogues and between these triterpenes are discussed.
Do Green And Golden Bell Frogs Litoria Aurea Occupy Habitats With Fungicidal Properties?, C G. Threlfall, Dianne F. Jolley, N Evershed, R L. Goldingay, W A. Buttemer
Do Green And Golden Bell Frogs Litoria Aurea Occupy Habitats With Fungicidal Properties?, C G. Threlfall, Dianne F. Jolley, N Evershed, R L. Goldingay, W A. Buttemer
Faculty of Science - Papers (Archive)
The Green and Golden Bell frog Utoria aurea is in major decline in Australia, where its distribution is now confined mainly to the east coast of New South Wales (NSW). Infection by the newly emerged amphibian fungal pathogen Batrachochytrium dendrobatidis has been identified as one of the main threats affecting L aureo. Surprisingly, some of the sites in NSW sustaining the largest populations of this species are industrial and urban habitats that are often disturbed and polluted, which could protect L aurea from chytrid infection if pollution had fungicidal capacity The aim of this study was to characterise the trace …
Deep-Sea Natural Products, Danielle Skropeta
Deep-Sea Natural Products, Danielle Skropeta
Faculty of Science - Papers (Archive)
This review covers the 390 novel marine natural products described to date from deep-water (>50 m)marine fauna, with details on the source organism, its depth and country of origin, along with anyreported biological activity of the metabolites. Relevant synthetic studies on the deep-sea naturalproducts have also been included.
The Proofreading Exonuclease Subunit E Of Escherichia Coli Dna Polymerase Iii Is Tethered To The Polymerase Subunit A Via A Flexible Linker, Kiyoshi Ozawa, Slobodan Jergic, Ah-Young Park, Nicholas E. Dixon, Gottfried Otting
The Proofreading Exonuclease Subunit E Of Escherichia Coli Dna Polymerase Iii Is Tethered To The Polymerase Subunit A Via A Flexible Linker, Kiyoshi Ozawa, Slobodan Jergic, Ah-Young Park, Nicholas E. Dixon, Gottfried Otting
Faculty of Science - Papers (Archive)
Escherichia coli DNA polymerase III holoenzyme is composed of 10 different subunits linked by noncovalent interactions. The polymerase activity resides in the α-subunit. The ε-subunit, which contains the proofreading exonuclease site within its N-terminal 185 residues, binds to α via a segment of 57 additional C-terminal residues, and also to θ, whose function is less well defined. The present study shows that θ greatly enhances the solubility of ε during cell-free synthesis. In addition, synthesis of ε in the presence of θ and α resulted in a soluble ternary complex that could readily be purified and analyzed by …
Exploiting The Borono-Mannich Reaction In Bioactive Alkaloid Synthesis, Stephen G. Pyne, Christopher Au, Andrew S. Davis, Ian R. Morgan, Thunwadee Ritthiwigrom, Arife Yazici
Exploiting The Borono-Mannich Reaction In Bioactive Alkaloid Synthesis, Stephen G. Pyne, Christopher Au, Andrew S. Davis, Ian R. Morgan, Thunwadee Ritthiwigrom, Arife Yazici
Faculty of Science - Papers (Archive)
We have demonstrated that the borono-Mannich reaction is a versatile and efficient reaction for the diastereoselective preparation of chiral 1,2-amino alcohols. These Mannich products are valuable starting materials as shown in this report by the synthesis of bioactive polyhydroxylated pyrrolizidine and indolizidine alkaloids. Initial studies, directed at the more complex Stemona alkaloids, using the borono-Mannich reaction on cyclic N-acyliminium ions are encouraging as demonstrated by the synthesis of the pyrido[1,2-a]azepine core structure of stemocurtisinol.
The Mitochondrial Genome Of The Stingless Bee Melipona Bicolor (Hymenoptera, Apidae, Meliponini): Sequence, Gene Organization And A Unique Trna Translocation Event Conserved Across The Tribe Meliponini, Daniela Silvestre, Mark P. Dowton, Maria C. Arias
The Mitochondrial Genome Of The Stingless Bee Melipona Bicolor (Hymenoptera, Apidae, Meliponini): Sequence, Gene Organization And A Unique Trna Translocation Event Conserved Across The Tribe Meliponini, Daniela Silvestre, Mark P. Dowton, Maria C. Arias
Faculty of Science - Papers (Archive)
No abstract provided.
Synthetic And Spectroscopic Studies On The Structures Of Uniflorines A And B: Structural Revision To 1,2,6,7-Tetrahydroxy-3-Hydroxymethylpyrrolizidine Alkaloids, Andrew S. Davis, Thunwadee Ritthiwigrom, Stephen G. Pyne
Synthetic And Spectroscopic Studies On The Structures Of Uniflorines A And B: Structural Revision To 1,2,6,7-Tetrahydroxy-3-Hydroxymethylpyrrolizidine Alkaloids, Andrew S. Davis, Thunwadee Ritthiwigrom, Stephen G. Pyne
Faculty of Science - Papers (Archive)
The diastereoselective synthesis of the C-2 epimer and the C-1, C-2 di-epimers of the putative structure of the alkaloid uniflorine A has been achieved. The synthesis of the latter di-epimers employed a novel pyrrolo[1,2-c]oxazin-1-one precursor to allow for the reversal of π-facial diastereoselectivity in an osmium(VIII)-catalyzed syn-dihydroxylation (DH) reaction. The NMR spectral data of these epimeric compounds and that of related isomers did not match that of the natural product. From a comparison of the NMR data of uniflorines A and B with that of casuarine and the known synthetic 1,2,6,7-tetrahydroxy-3-hydroxymethylpyrrolizidine isomers we concluded unequivocally that uniflorine …
Antimalarial Activity Of 2,4-Diaminopyrimidines, J. Morgan, R. Haritakul, Paul A. Keller
Antimalarial Activity Of 2,4-Diaminopyrimidines, J. Morgan, R. Haritakul, Paul A. Keller
Faculty of Science - Papers (Archive)
A series of 2,4- and 4,6-diaminopyrimidines were prepared and evaluated for their in vitro antimalarial activity. Of the 12 compounds tested 7 showed reasonable activity with 1 having a sub-micromolar IC50.
Oxidative Coupling Of Indoles Using Thallium(Iii) Trifluoroacetate, Paul A. Keller, N. R. Yepuri, M. J. Kelso, M. Mariani, B. W. Skelton, A. H. White
Oxidative Coupling Of Indoles Using Thallium(Iii) Trifluoroacetate, Paul A. Keller, N. R. Yepuri, M. J. Kelso, M. Mariani, B. W. Skelton, A. H. White
Faculty of Science - Papers (Archive)
The oxidative coupling of polysubstituted electron-rich indoles mediated by thallium trifluoroacetate was found to be a facile, clean, and high yielding reaction. Indolic coupling sites were determined by the nature of the substituents present, with dimerisation at the indole 2-position being the dominant outcome. Indoles bearing two potential reaction sites with similar reactivity were additionally found to undergo heterocoupling.
New Cyclic Peptides Via Ring-Closing Metathesis Reactions And Their Anti-Bacterial Activities, Timothy P. Boyle, John B. Bremner, Jonathan Coates, John Deadman, Paul A. Keller, Stephen G. Pyne, David I. Rhodes
New Cyclic Peptides Via Ring-Closing Metathesis Reactions And Their Anti-Bacterial Activities, Timothy P. Boyle, John B. Bremner, Jonathan Coates, John Deadman, Paul A. Keller, Stephen G. Pyne, David I. Rhodes
Faculty of Science - Papers (Archive)
As part of a program investigating cyclic peptides with an internal aromatic hydrophobic scaffold as potential novel anti-bacterial agents, we explored the synthesis of simple tyrosine-based systems. These were prepared via key intermediates containing internal allylglycine and allyltyrosine residues for subsequent ring closing metathesis reactions. Although the resulting anti-bacterial activity against Staphylococcus aureus was modest, this represents a novel and simple route to this class of compounds. One intermediate acyclic dipeptide precursor showed good activity against S. aureus with an MIC of 7.8 µg/mL.
Unraveling The Mysteries Of Protein Folding And Misfolding, Heath Ecroyd, John A. Carver
Unraveling The Mysteries Of Protein Folding And Misfolding, Heath Ecroyd, John A. Carver
Faculty of Science - Papers (Archive)
This mini-review focuses on the processes and consequences of protein folding and misfolding. The latter process often leads to protein aggregation and precipitation with the aggregates adopting either highly ordered (amyloid fibril) or disordered (amorphous) forms. In particular, the amyloid fibril is discussed because this form has gained considerable notoriety due to its close links to a variety of debilitating diseases including Alzheimer's, Parkinson's, Huntington's, and Creutzfeldt-Jakob diseases, and type-II diabetes. In each of these diseases a different protein forms fibrils, yet the fibrils formed have a very similar structure. The mechanism by which fibrils form, fibril structure, and the …
Dissociation From The Oligomeric State Is The Rate-Limiting Step In Fibril Formation By Kappa-Casein, Heath Ecroyd, Tomas Koudelka, David Thorn, Danielle M. Williams, Glyn Devlin, Peter Hoffmann, John A. Carver
Dissociation From The Oligomeric State Is The Rate-Limiting Step In Fibril Formation By Kappa-Casein, Heath Ecroyd, Tomas Koudelka, David Thorn, Danielle M. Williams, Glyn Devlin, Peter Hoffmann, John A. Carver
Faculty of Science - Papers (Archive)
Amyloid fibrils are aggregated and precipitated forms of protein in which the protein exists in highly ordered, long, unbranching threadlike formations that are stable and resistant to degradation by proteases. Fibril formation is an ordered process that typically involves the unfolding of a protein to partially folded states that subsequently interact and aggregate through a nucleation-dependent mechanism. Here we report on studies investigating the molecular basis of the inherent propensity of the milk protein, kappa-casein, to form amyloid fibrils. Using reduced and carboxymethylated kappa-casein ( RCM kappa-CN), we show that fibril formation is accompanied by a characteristic increase in thioflavin …
Instant Insight: Think Outside The Cell, Mark R. Wilson, Justin J. Yerbury
Instant Insight: Think Outside The Cell, Mark R. Wilson, Justin J. Yerbury
Faculty of Science - Papers (Archive)
Proteins perform many different functions critical for life, from building our muscle structure to digesting our food. These large biological molecules each have a unique three-dimensional shape which they require to perform their function. In protein deposition diseases (PDDs), however, a disease-specific protein molecule unfolds from its normal shape and assembles together with like molecules into insoluble rod-shaped fibrils. These protein deposits can be found in the brain, skeletal tissue and various organs; in some cases they may become large enough to disrupt tissue structure and function.
Clusterin Interacts With Paclitaxel And Confer Paclitaxel Resistance In Ovarian Cancer, Dong Choon Park, Seung Geun Yeo, Mark R. Wilson, Justin J. Yerbury, Joseph Kwong, William R. Welch, Yang Kyu Choi, Michael J. Birrer, Samuel C. Mok, Kwong-Kwok Wong
Clusterin Interacts With Paclitaxel And Confer Paclitaxel Resistance In Ovarian Cancer, Dong Choon Park, Seung Geun Yeo, Mark R. Wilson, Justin J. Yerbury, Joseph Kwong, William R. Welch, Yang Kyu Choi, Michael J. Birrer, Samuel C. Mok, Kwong-Kwok Wong
Faculty of Science - Papers (Archive)
Optimal debulking followed by chemotherapy is the standard treatment of managing late-stage ovarian cancer, but chemoresistance is still a major problem. In this study, we compared expression profiles of primary tumor tissue from five long-term (>8 years) and five short-term (years) ovarian cancer survivors and identified clusterin as one of the genes that were significantly up-regulated in short-term survivors. We then evaluated the prognostic significance of clusterin and its possible correlation with chemoresistance in ovarian cancer by immunohistostaining of clusterin in 62 tumor samples from patients with stage III, high-grade serous ovarian cancer. After adjusting for debulking status and …
Extracellular Chaperones And Amyloids, Mark R. Wilson, Justin J. Yerbury, Stephen Poon
Extracellular Chaperones And Amyloids, Mark R. Wilson, Justin J. Yerbury, Stephen Poon
Faculty of Science - Papers (Archive)
The pathology of more than 40 human degenerative diseases is associated with fibrillar proteinaceous deposits called amyloid. Collectively referred to as protein deposition diseases, many of these affect the brain and the central nervous system. In many cases the amyloid deposits are extracellular and are found associated with newly identified abundant extracellular chaperones (ECs). Evidence is discussed which suggests an important regulatory role for ECs in amyloid formation and disposal in vivo. This is emerging as an exciting field. A model is presented in which it is proposed that, under normal conditions, ECs stabilize extracellular misfolded proteins by binding to …
The Key Importance Of Soy Isoflavone Bioavailability To Understanding Health Benefits, T. A. Larkin, William E. Price, L. Astheimer
The Key Importance Of Soy Isoflavone Bioavailability To Understanding Health Benefits, T. A. Larkin, William E. Price, L. Astheimer
Faculty of Science - Papers (Archive)
Research over the past two decades has provided significant epidemiological and other evidence for the health benefits of the consumption of soy-based foods. A large number of dietary intervention studies have examined the effects of soy isoflavones on risk factors for cardiovascular disease and hormone-dependent cancers. However, these report large variability in outcome measures, very limited reproducibility between studies and in some cases, controversy between results of clinical trials using dietary soy or soy protein and isoflavone supplementation. This highlights a major gap in our understanding of soy isoflavone uptake, metabolism, distribution, and overall bioavailability. There are many potential factors …
Diastereoselective Ritter Reactions Of Chiral Cyclic N-Acyliminium Ions: Synthesis Of Pyrido- And Pyrrolo [2,3-D] Oxazoles And 4-Hydroxy-5-N-Acylaminopyrrolidines And 5-Hydroxy-6-N-Acylaminopiperidines, Ian R. Morgan, Arife Yazici, Stephen G. Pyne, Brian W. Skelton
Diastereoselective Ritter Reactions Of Chiral Cyclic N-Acyliminium Ions: Synthesis Of Pyrido- And Pyrrolo [2,3-D] Oxazoles And 4-Hydroxy-5-N-Acylaminopyrrolidines And 5-Hydroxy-6-N-Acylaminopiperidines, Ian R. Morgan, Arife Yazici, Stephen G. Pyne, Brian W. Skelton
Faculty of Science - Papers (Archive)
Pyrido- and pyrrolo[2,3-d]oxazoles can be conveniently prepared in high yield from the Ritter reaction of nitriles and in situ generated chiral cyclic N-acyliminium ions. cis-4-Hydroxy-5-acylaminopyrrolidines and cis-5-hydroxy-6-acylaminopiperidines can be readily obtained by acid hydrolysis of these bicyclic heterocyclic compounds, respectively.
On The Electrodeposition Of Titanium In Ionic Liquids, William E. Price, Gordon G. Wallace, Douglas Macfarlane, S Z. El Abedin, A Y. Saad, F Endres, E M. Moustafa, P J. Newman, A Bund, N Borissenko
On The Electrodeposition Of Titanium In Ionic Liquids, William E. Price, Gordon G. Wallace, Douglas Macfarlane, S Z. El Abedin, A Y. Saad, F Endres, E M. Moustafa, P J. Newman, A Bund, N Borissenko
Faculty of Science - Papers (Archive)
The ability to electrodeposit titanium at low temperatures would be an important breakthrough for making corrosion resistant layers on a variety of technically important materials. Ionic liquids have often been considered as suitable solvents for the electrodeposition of titanium. In the present paper we have extensively investigated whether titanium can be electrodeposited from its halides (TiCl4, TiF4, TiI4) in different ionic liquids, namely1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]Tf2N), 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)amide ([BMP]Tf2N), and trihexyltetradecyl-phosphonium bis(trifluoromethylsulfonyl)amide ([P14,6,6,6]Tf2N). Cyclic voltammetry and EQCM measurements show that, instead of elemental Ti, only non-stoichiometric halides are formed, …
Comparison Of Mass Spectrometry And Other Techniques For Probing Interactions Between Metal Complexes And Dna, Thitima Urathamakul, Daniel J. Waller, Jennifer L. Beck, Janice Aldrich-Wright, Stephen F. Ralph
Comparison Of Mass Spectrometry And Other Techniques For Probing Interactions Between Metal Complexes And Dna, Thitima Urathamakul, Daniel J. Waller, Jennifer L. Beck, Janice Aldrich-Wright, Stephen F. Ralph
Faculty of Science - Papers (Archive)
Electrospray ionization mass spectrometry (ESI-MS) was used to study the binding interactions of two series of ruthenium complexes, [Ru(phen)2L]2+ and [RuL′2(dpqC)]2+, to a double stranded DNA hexadecamer, and derive orders of relative binding affinity. These were shown to be in good agreement with orders of relative binding affinity derived from absorption and circular dichroism (CD) spectroscopic examination of the same systems and from DNA melting curves. However, the extent of luminescence enhancement caused by the addition of DNA to solutions of the ruthenium complexes showed little correlation with orders of binding affinity derived from ESI-MS or any of the other …
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Faculty of Science - Papers (Archive)
Ions formed from lipids during electrospray ionization of crude lipid extracts have been mass-selected within a quadrupole linear ion trap mass spectrometer and allowed to react with ozone vapor. Gas-phase ion−molecule reactions between unsaturated lipid ions and ozone are found to yield two primary product ions for each carbon−carbon double bond within the molecule. The mass-to-charge ratios of these chemically induced fragments are diagnostic of the position of unsaturation within the precursor ion. This novel analytical technique, dubbed ozone-induced dissociation (OzID), can be applied both in series and in parallel with conventional collision-induced dissociation (CID) to provide near-complete structural assignment …