Physical Sciences and Mathematics Commons^™

Short Telomeres In Hatchling Snakes: Erythrocyte Telomere Dynamics And Longevity In Tropical Pythons, Beata Ujvari, Thomas Madsen

Faculty of Science - Papers (Archive)

Background: Telomere length (TL) has been found to be associated with life span in birds and humans. However, other studies have demonstrated that TL does not affect survival among old humans. Furthermore, replicative senescence has been shown to be induced by changes in the protected status of the telomeres rather than the loss of TL. In the present study we explore whether age- and sex-specific telomere dynamics affect life span in a long-lived snake, the water python (Liasis fuscus). Methodology/Principal Findings: Erythrocyte TL was measured using the Telo TAGGG TL Assay Kit (Roche). In contrast to other vertebrates, TL of …

Sex-Specific Developmental Plasticity In Response To Yolk Corticosterone In An Oviparous Lizard, Tobias O. Uller, Johan Hollander, Lee Astheimer, Mats M. Olsson

Faculty of Science - Papers (Archive)

Corticosterone exposure during prenatal development as a result of maternal upregulation of circulating hormone levels has been shown to have effects on offspring development in mammals. Corticosterone has also been documented in egg yolk in oviparous vertebrates, but the extent to which this influences phenotypic development is less studied. We show that maternal corticosterone is transferred to egg yolk in an oviparous lizard (the mallee dragon, Ctenophorus fordi Storr), with significant variation among clutches in hormone levels. Experimental elevation of yolk corticosterone did not affect hatching success, incubation period or offspring sex ratio. However, corticosterone did have a sex-specific effect …

Plasma Cholinesterase Characteristics In Native Australian Birds: Significance For Monitoring Avian Species For Pesticide Exposure, Karen J. Fildes, Judit K. Szabo, Lee Astheimer, Michael Hooper, William A. Buttemer

Faculty of Science - Papers (Archive)

Cholinesterase-inhibiting pesticides are applied throughout Australia to control agricultural pests. Blood plasma cholinesterase (ChE) activity is a sensitive indicator of exposure to organophosphorus insecticides in vertebrates. To aid biomonitoring and provide reference data for wildlife pesticide-risk assessment, plasma acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were characterised in nine species of native bird: King Quails (Excalfactoria chinensis), Budgerigars (Melopsittacus undulatus), White-plumed Honeyeaters (Lichenostomas penicillatus), Yellow-throated Miners (Manorina flavigula), Willie Wagtails (Rhipidura leucophrys), Australian Reed-Warblers (Acrocephalus australis), Brown Songlarks (Cincloramphus cruralis), Double-barred Finches (Taeniopygia bichenovii) and Australasian Pipits (Anthus novaeseelandiae). Plasma ChE activities in all species were within the range of most …

Increased Mortality Of Naive Varanid Lizards After The Invasion Of Non-Native Cane Toads (Bufo Marinus), Thomas Madsen, Beata Ujvari

Faculty of Science - Papers (Archive)

Exotic animal and plant species introduced into the Australian continent often imparted catastrophic effects on the indigenous fauna and flora. Proponents of biological control introduced the South American Cane Toad (Bufo marinus) into the sugar cane fields of Queensland in 1935. The Cane Toad is one of the most toxic bufonids, and when seized by naïve Australian predators, the toxin usually kills the attacker. One group of Australian squamate reptiles that are very susceptible to Cane Toad toxins is varanid lizards. Prior to Cane Toad invasion of our study area, the Adelaide River floodplain of the Northern Territory of Australia, …

Spatial Ecology Of Hatchling Water Pythons (Liasis Fuscus) In Tropical Australia, Richard Shine, Thomas R. Madsen, Ligia Pizzatto, Gregory P. Brown

Faculty of Science - Papers (Archive)

Young snakes are rarely seen in the field and little is known about their habits. mostly because they are too small for radio-telemetry (the primary method for Studying snake spatial ecology). However, the offspring or some larger species can be fitted with transmitters and we investigated the spatial ecology and habitat use of ten hatchling water pythons (Liasis fuscus: Pythonidae) in the floodplain of the Adelaide River, tropical Australia. Patterns of habitat use in the late wet season and during the dry season were similar to those of adults tracked in the same vicinity in an earlier study. Soon after …

Antarctic State Of The Environment Indicator 72 - Windmill Islands Terrestrial Vegetation Dynamics., Sharon A. Robinson

Faculty of Science - Papers (Archive)

Survey of quadrats along permanent transects in the Windmill Islands, East Antarctica, involving: quantitative analysis of relative bryophyte species distribution and abundance; area moribund versus healthy moss.

Geological Setting Of Australasian Coal Deposits, Adrian C. Hutton

Faculty of Science - Papers (Archive)

Coal was discovered in Australia in 1791 by William Bryant, a convict, near the mouth of the Hunter River at Newcastle, New South Wales (NSW). Later discoveries were made along the Brisbane River and ncar Ipswich in the 1820s. Mining commenced in Australia in 1799, also in NSW. The earliest scientific input to coal exploration was when Sir Joseph Banks, in 1799, introduced drilling equipment to Australia (Bryan, 1990a). Since then, production of coal has occurred in all states with the exception of the Northern Territory. In NSW, Queensland and Western Australia the mined coal is predominantly of bituminous rank, …

Local Engagements With Urban Bushland: Moving Beyond Bounded Practice For Urban Biodiversity Management, Nicholas J. Gill, Gordon R. Waitt, Lesley M. Head

Faculty of Science - Papers (Archive)

Management of ecologically significant urban green space is likely to be increasingly governed by biodiversity policy frameworks. These frameworks tend to reproduce bounded thinking and strategies that separate green space from its context and characterise people as a disturbance. Like many green spaces these ecologically significant areas are highly valued by visitors and nearby residents. Green space is important for engagement with nature, social interaction, and for respite from daily life: it is strongly connected to surrounding areas and to the lives of people who live there. The dissonance between bounded management thinking and the role of green space in …

Ancestral Landscapes Of The Pueblo World, Lesley M. Head

Faculty of Science - Papers (Archive)

No abstract provided.

Sensible Heat Loss From Muskoxen (Ovibos Moschatus) Feeding In Winter: Small Calves Are Not At A Thermal Disadvantage Compared With Adult Cows, Adam J. Munn, Perry S. Barboza, Jon Dehn

Faculty of Science - Papers (Archive)

Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% …

On The Utilization Of Energy Minimization To The Study Of Ion Selectivity, Haibo Yu, Benoit Roux

Faculty of Science - Papers (Archive)

The major pitfalls in studying ion selectivity in binding site models using energy minimization based methods are examined and discussed. It is shown that the properties derived from energy minimization are strongly configuration-dependent and that the results should be interpreted with caution. It is concluded that computational studies of ion selectivity must include thermal fluctuations and entropic effects.

Discovery Of A Non-Peptidic Inhibitor Of West Nile Virus Ns3 Protease By High-Throughput Docking, Dariusz Ekonomiuk, Xun-Cheng Su, Kiyoshi Ozawa, Chrisophe Bodenreider, Siew Pheng Lim, Zheng Yin, Thomas H. Keller, David Beer, Viral Patel, Gottfried Otting, Amedeo Calflisch, Danzhi Huang

Faculty of Science - Papers (Archive)

No abstract provided.

Glutarate And N-Acetyl-L-Glutamate Buffers For Cell-Free Synthesis Of Selectively 15n-Labelled Proteins, X Jia, Kiyoshi Ozawa, K Loscha, G Otting

Faculty of Science - Papers (Archive)

Cell-free protein synthesis provides rapid and economical access to selectively 15N-labelled proteins, greatly facilitating the assignment of 15N-HSQC spectra. While the best yields are usually obtained with buffers containing high concentrations of potassium L-glutamate, preparation of selectively 15N-Glu labelled samples requires non-standard conditions. Among many compounds tested to replace the L-Glu buffer, potassium N-acetyl-L-glutamate and potassium glutarate were found to perform best, delivering high yields for all proteins tested, with preserved selectivity of 15N-Glu labelling. Assessment of amino-transferase activity by combinatorial 15N-labelling revealed that glutarate and N-acetyl-L-glutamate suppress the transfer of the 15N-alpha-amino groups between amino acids less well than …

Nmr Study Of Complexes Between Low Molecular Mass Inhibitors And The West Nile Virus Ns2b-Ns3 Protease, X Su, Kiyoshi Ozawa, Hiromasa Yagi, S P. Lim, D Wen, D Ekonomiuk, D Huang, T Keller, S Sonntag, A Caflisch, S G. Vasudevan, G Otting

Faculty of Science - Papers (Archive)

The two-component NS2B-NS3 protease of West Nile virus is essential for its replication and presents an attractive target for drug development. Here, we describe protocols for the high-yield expression of stable isotope-labelled samples in vivo and in vitro. We also describe the use of NMR spectroscopy to determine the binding mode of new low molecular mass inhibitors of the West Nile virus NS2B-NS3 protease which were discovered using high-throughput in vitro screening. Binding to the substrate-binding sites S1 and S3 is confirmed by intermolecular NOEs and comparison with the binding mode of a previously identified low molecular mass inhibitor. Our …

A Fluorescence Quenching Assay To Discriminate Between Specific And Non-Specific Inhibitors Of Dengue Virus Protease, C Bodenreider, D Beer, T Keller, S Sonntag, D Wen, Li Yap, Y H Yau, S G Shocat, D Huang, T Zhou, A Caflisch, X C Su, Kiyoshi Ozawa, G Otting, S G. Vasudevan, J Lescar, S P. Lim

Faculty of Science - Papers (Archive)

In drug discovery, the occurrence of false positives is a major hurdle in the search for lead compounds that can be developed into drugs. A small-molecular-weight compound that inhibits dengue virus protease at low micromolar levels was identified in a screening campaign. Binding to the enzyme was confirmed by isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR). However, a structure-activity relationship study that ensued did not yield more potent leads. To further characterize the parental compound and its analogues, we developed a high-speed, low-cost, quantitative fluorescence quenching assay. We observed that specific analogues quenched dengue protease fluorescence and showed …

Nmr Analysis Of The Dynamic Exchange Of The Ns2b Cofactor Between Open And Closed Conformations Of The West Nile Virus Ns2b-Ns3 Protease, X Su, Kiyoshi Ozawa, R Qi, S G. Vasudevan, S P. Lim, G Otting

Faculty of Science - Papers (Archive)

Background: The two-component NS2B-NS3 proteases of West Nile and dengue viruses are essential for viral replication and established targets for drug development. In all crystal structures of the proteases to date, the NS2B cofactor is located far from the substrate binding site (open conformation) in the absence of inhibitor and lining the substrate binding site (closed conformation) in the presence of an inhibitor. Methods: In this work, nuclear magnetic resonance (NMR) spectroscopy of isotope and spin-labeled samples of the West Nile virus protease was used to investigate the occurrence of equilibria between open and closed conformations in solution. Findings: In …

Beads, Boats And Switches: Making Things Happen With Molecular Photoswitches, Robert P. Byrne, Silvia Scaramagnani, Michael J. Higgins, Gordon G. Wallace, Dermot Diamond

Faculty of Science - Papers (Archive)

In this paper we present recent results obtained with a stimulus-responsive materials based on the photo-switchable behaviour exhibited by spiro-cyclic derivatives. Our results suggest that these highly novel materials offer unique capabilities hitherto inaccessible using conventional materials. In particular, we will focus on photocontrolled guest binding and release, inherent signalling of status, photo-actuation and solvent driven motion of small structures as examples of the fascinating behaviour of these exceptional materials. Copyright 2009 IEEE NANO Organizers.

Predicting Avian Distributions To Evaluate Spatiotemporal Overlap With Locust Control Operations In Eastern Australia, Judit K. Szabo, Pamela J. Davy, Michael Hooper, Lee Astheimer

Faculty of Science - Papers (Archive)

Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences …

Real-Time Single-Molecule Observation Of Rolling-Circle Dna Replication, Nathan A. Tanner, Joseph J. Loparo, Samir M. Hamdan, Slobodan Jergic, Nicholas E. Dixon, Antoine M. Van Oijen

Faculty of Science - Papers (Archive)

We present a simple technique for visualizing replication of individual DNA molecules in real time. By attaching a rolling-circle substrate to a TIRF microscope-mounted flow chamber, we are able to monitor the progression of single-DNA synthesis events and accurately measure rates and processivities of single T7 and Escherichia coli replisomes as they replicate DNA. This method allows for rapid and precise characterization of the kinetics of DNA synthesis and the effects of replication inhibitors.

A Hypomorphic Vasopressin Allele Prevents Anxiety-Related Behavior, Mirjam Bunck, Ludwig Czibere, Charlotte Horvath, Cornelia Graf, Elisabeth T. Frank, Melanie S. Kebler, Chris Murgatroyd, Bertram Muller-Myhsok, Mariya Gonik, Peter Weber, Benno Putz, Patrik Muigg, Markus Panhuysen, Nicolas Singewald, Thomas Bettecken, Jan M. Deussing, Florian Holsboer, Dietmar Spengler, Rainer Landgraf

Faculty of Science - Papers (Archive)

In this study, microarray analysis, in situ hybridization, quantitative real-time PCR and immunohistochemistry revealed decreased expression of the vasopressin gene (Avp) in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei of adult LAB mice compared to HAB, NAB (normal anxiety-related behavior) and HABxLAB F1 intercross controls, without detecting differences in receptor expression or density. By sequencing the regions 2.5 kbp up- and downstream of the Avp gene locus, we could identify several polymorphic loci, differing between the HAB and LAB lines. In the gene promoter, a deletion of twelve bp Δ(−2180–2191) is particularly likely to contribute to the reduced Avp …

Consistent Paternity Skew Through Ontogeny In Peron's Tree Frog (Litoria Peronii), Craig D. Sherman, Erik Wapstra, Mats M. Olsson

Faculty of Science - Papers (Archive)

Background: A large number of studies in postcopulatory sexual selection use paternity success as a proxy for fertilization success. However, selective mortality during embryonic development can lead to skews in paternity in situations of polyandry and sperm competition. Thus, when assessment of paternity fails to incorporate mortality skews during early ontogeny, this may interfere with correct interpretation of results and subsequent evolutionary inference. In a previous series of in vitro sperm competition experiments with amphibians (Litoria peronii), we showed skewed paternity patterns towards males more genetically similar to the female.

Methodology/Principal Findings: Here we use in vitro fertilizations and sperm …

A Hybrid Approach To Estuary Modelling, O. Gould, J. Hinwood, Errol J. Mclean

Faculty of Science - Papers (Archive)

A hybrid model incorporating process and system modelling characteristics has been developed and applied to the evolution of a theoretical estuary with a small lake basin, partially enclosed by a barrier with an entrance open to the sea. The one-dimensional model is capable of modelling changes in sedimentation both spatially and temporally and hence, tracks changes in crosssection dimensions along the estuary. The model structure is a series of linked modules to solve the hydrodynamics, the sediment transport equation and a distribution of the sediment to bed and bank. An evolution simulation was conducted for a generic coastal lagoon over …

Carbon-Nanotube Biofiber Microelectrodes, Carol M. Lynam, Gordon G. Wallace, Willo Grosse

Faculty of Science - Papers (Archive)

All-biocompatible carbon-nanotube fibers were formed using wet spinning. In this process the spinning solutions used are carbon nanotubes dispersed using biomolecules such as hyaluronic acid and chitosan. We compare the effect of a coagulation bath containing either a polymer binder, e.g., polyethyleneimine, or simply a precipitating solvent system, e.g., acetone. The electrical, mechanical, and morphological properties of the resulting fibers were studied. Biocompatible electrode structures were generated suitable for a variety of biomedical applications, e.g.,in biosensors or in systems where the application of an electrical field is advantageous e.g., stimulation of electrically excitable cells such as nerve and muscle cells.

The Major Toxin From The Australian Common Brown Snake Is A Hexamer With Unusual Gas-Phase Dissociation Properties, Andrew Aquilina

Faculty of Science - Papers (Archive)

Asymmetric dissociation of multiply charged proteins assemblies has been frequently reported. This phenomenon, which relies on the dissociation of one or more highly charged monomers, has been shown to provide insights into the structure and organization of large monodisperse and polydisperse assemblies. Here, the process of asymmetric dissociation is investigated using the multi-subunit protein, textilotoxin, which has unusually high structural constraints on its monomers due to multiple disulfide linkages. Initially, it is shown that, contrary to previous reports, textilotoxin is made up of 6, rather than 5 subunits. Furthermore, the hexamer exists as two isoforms, one of which is substantially …

Intermolecular Addition Reactions Of N-Acyliminium Ions (Part Ii), Arife Yazici, Stephen G. Pyne

Faculty of Science - Papers (Archive)

This review highlights the advances in the literature up to July 2008 on the intermolecular reactions of acyclic and cyclic N-acyliminium ions. This is an update of an earlier review in 2000 oil this topic and does not include intramolecular addition reactions to N-acyliminium ions which was recently reviewed. This review is presented in two parts, with the first part having dealt with acyclic and pyrrolidinone-based N-acyliminium ions. Part II continues with other five-membered heterocyclic derivatives and higher systems.

Intermolecular Addition Reactions Of N-Acyliminium Ions (Part I), Arife Yazici, Stephen G. Pyne

Faculty of Science - Papers (Archive)

This review highlights the advances in the literature up to July 2008 on the intermolecular reactions of acyclic and cyclic N-acyliminium ions. This is an update of an earlier review in 2000 on this topic and does not include intramolecular addition reactions to N-acyliminium ions which was recently reviewed. This review is presented in two parts, with the first part dealing with acyclic and pyrrolidinone-based N-acyliminium ions. Part II continues with other five-membered heterocyclic derivatives and higher systems.

Synthesis Of Novel N-Protected Hydrophobic Phenylalanines And Their Application In Potential Antibacterials, Timothy P. Boyle, J. B. Bremner, Jonathan A. Coates, John Deadman, Paul A. Keller, Stephen G. Pyne, Kittiya Somphol

Faculty of Science - Papers (Archive)

An efficient synthesis of two new N-acetyl-4’-arylphenylalanines is described together with their incorporation in to a number of cationic peptoid antibacterial agents, one of which had an MIC of 7.8 μg/mL against Staphylococcus aureus.

Spectroscopic Study Of The Benchmark Mn+-H2 Complex, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske

Faculty of Science - Papers (Archive)

We have recorded the rotationally resolved infrared spectrum of the weakly bound Mn+-H2 complex in the H-H stretch region (4022-4078 cm(-1)) by monitoring Mn+ photodissociation products. The band center of Mn+-H2, the H-H stretch transition, is shifted by -111.8 cm(-1) from the transition of the free H2 molecule. The spectroscopic data suggest that the Mn+-H2 complex consists of a slightly perturbed H2 molecule attached to the Mn+ ion in a T-shaped configuration with a vibrationally averaged intermolecular separation of 2.73 A. Together with the measured Mn+...H2 binding energy of 7.9 kJ/mol (Weis, P.; et al. J. Phys. Chem. A 1997, …

Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske

Faculty of Science - Papers (Archive)

Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground …

Sandy Creek Gorge; Humans, Palaeofloods And Landscape Evolution, John D. Jansen, Derek Fabel

Faculty of Science - Papers (Archive)

No abstract provided.