School of Biological Sciences Publications - UQ eSpace

Allosteric Control Of Oxygen Binding By Haemoglobin During Embryonic Development In The Crocodile Crocodylus porosus: The Role Of Red Cell Organic Phosphates And Carbon Dioxide

2004-11-30T00:00:00Z

The P50 of whole blood [30 degrees C, PCO2=2.08 kPa (15.6 mmHg)] decreases during embryonic development from approximately 6.7 kPa (50 mmHg) at 15 days to about half this value at hatching (86 days), paralleling a decrease in ATP from 100 to 5-10 micromole g-1 Hb. There is also a progressive changeover from embryonic to adult haemoglobin (HbA). A pulse of 2,3- diphosphoglycerate (2,3-DPG) (18 micromole g-1 Hb) occurs late in embryonic life. It has no effect on whole-blood oxygen-affinity and falls rapidly at hatching to values typical of post-hatchling crocodilians in general (<1.0 micromole g-1 Hb). ATP has a marked effect on the oxygen affinity of embryonic haemoglobin (HbE) but not on HbA. 2,3-DPG has only very small effects on the oxygen affinities of HbE and HbA. CO2 has a small effect on the oxygen affinity of HbE but a marked effect on that of HbA. Values of PO2 measured in the chorio-allantoic artery [2.9 kPa (22 mmHg)] and vein [5.9 kPa (52 mmHg)] imply an increase in saturation from approximately 30 % to more than 80 %. Neither whole-blood oxygen-affinity nor ATP level was altered in response to an experimental 7-day exposure to low ambient oxygen levels [10.7 kPa (80 mmHg)]. The results do not lend themselves easily to the pan-selectionist paradigm in which all physiological traits are viewed as being adaptive.

Alteration of photosystem II properties with non-photochemical excitation quenching - Discussion

2007-08-13T00:00:00Z

Altered fungal sensitivity to a plant antimicrobial peptide through over-expression of yeast cDNAs

2007-08-15T00:00:00Z

A yeast cDNA expression library was screened to identify genes and cellular processes that influence fungal sensitivity to a plant antimicrobial peptide. A plasmid-based, GAL1 promoter-driven yeast cDNA expression library was introduced into a yeast genotype susceptible to the antimicrobial peptide MiAMP1 purified from Macadamia integrifolia. Following a screen of 20,000 cDNAs, three yeast cDNAs were identified that reproducibly provided transformants with galactose-dependent resistance to MiAMP1. These cDNAs encoded a protein of unknown function, a component (VMA11) of the vacuolar H+-ATPase and a component (cytochrome c oxidase subunit VIa) of the mitochondrial electron transport chain, respectively. To identify genes that increased sensitivity to MiAMP1, the yeast cDNA expression library was introduced into a yeast mutant with increased resistance to MiAMP1. From 11,000 cDNAs screened, two cDNA clones corresponding to a ser/thr kinase and a ser/thr phosphatase reproducibly increased MiAMP1 susceptibility in the mutant in a galactose-dependent manner. Deletion mutants were available for three of the five genes identified but showed no change in their sensitivity to MiAMP1, indicating that these genes could not be detected by screening of yeast deletion mutant libraries. Yeast cDNA expression library screening therefore provides an alternative approach to gene deletion libraries to identify genes that can influence the sensitivity of fungi to plant antimicrobial peptides.

Altering sugarcane shoot architecture through genetic engineering: prospects for increasing cane and sugar yield

2008-05-22T00:00:00Z

Alternative fungicides for controlling husk spot caused by Pseudocercospora macadamiae in macadamia

2008-12-19T09:45:34Z

Husk spot, caused by Pseudocercospora macadamiae is a major fungal disease of macadamia in Australia. Chemicals to control the disease are limited and frequent failure to control the disease is a major concern to growers. The overall goal of this research was to improve the chemical control strategy of P. macadamiae through the provision of fungicides with different modes of action to carbendazim, which is the current industry standard. Husk spot incidence, premature fruit abscission, kernel quality and yield were evaluated following application of different fungicide products in replicated field experiments at three different sites. Results showed significant differences in disease incidence and premature fruit abscission between fungicide treatments, field sites and years. Generally, disease incidence and premature fruit abscission on trees treated with fungicide were significantly (P < 0.05) lower than the untreated control. Pyraclostrobin conferred significantly better protection than trifloxystrobin, reducing disease severity by 70% compared with a 50% reduction by trifloxystrobin. The pyraclostrobin treatment had a similar efficacy to the current industry standard (70% reduction cf. 73% reduction by tank-mixed carbendazim and copper). Higher amounts of immature kernels occurred in the untreated control, followed by difenoconazole and trifloxystrobin. Diseased fruit accounted for 78% of premature fruit abscission, which indicates that husk spot enhances fruit abscission in macadamia. Our results suggest that pyraclostrobin provided similar efficacy to the industry standard and could, therefore, play a key role in the management of husk spot.

Alternatively spliced products of the human kinesin light chain 1 (KNS2) gene

2007-08-15T00:00:00Z

Conventional kinesin is a microtubule-based molecular motor involved in the transport of membranous and non-membranous cargoes. The kinesin holoenzyme exists as a heterotetramer, consisting of two heavy chain and two light chain subunits. It is thought that one function of the light chains is to interact with the cargo. Alternative splicing of kinesin light chain pre-mRNA has been observed in lower organisms, although evidence for alternative splicing of the human gene has not been reported. We have identified 19 variants of the human KNS2 gene (KLC1) that are generated by alternative splicing of downstream exons, but calculate that KNS2 has the potential to produce 285919 spliceforms. Corresponding spliceforms of the mouse KLC1 gene were also identified. The alternative exons are all located 3' of exon 12 and the novel spliceforms produce both alternative carboxy termini and alternative 3' untranslated regions. The observation of multiple light chain isoforms is consistent with their proposed role in specific cargo attachment.

Alternative states models provide an effective framework for invasive species control and restoration of native communities

Firn, J og House, APN og Buckley, YM — 2010-02-21T00:00:00Z

Altitudinal variation in behavioural thermoregulation: Local adaptation vs. plasticity in California grasshoppers

Samietz, J. og Salser, M. A. og Dingle, H. — 2007-08-15T00:00:00Z

We investigated the adaptive significance of behavioural thermoregulation in univoltine populations of the grasshopper Melanoplus sanguinipes along an altitudinal gradient in California using laboratory tests of animals raised under different temperatures. Trials consisted of continuous body temperature measurements with semi-implanted microprobes in a test arena, and observation and simultaneous recording of behavioural responses. These responses included mobility, basking and orientation of the body axes (aspect angle) towards a radiation source. Mobility and basking are determined by the altitudinal origin of the parental generation and not by the temperature treatments. With increasing altitude, individuals tend increasingly to raise body temperatures via mobility and increased basking. In contrast, body orientation towards the radiation source is influenced by the temperature treatments but not by the altitude of origin. Individuals experiencing higher temperatures during rearing show a lower tendency to lateral flanking. We conclude that body orientation responses are not adapted locally. In contrast other components of the behavioural syndrome that increase body temperature, such as mobility and basking, are adaptive in response to local selection pressure. The thermoregulatory syndrome of these grasshoppers is an important contribution to life-history adaptations that appropriately match season lengths.

A manipulative test of competing theories for metabolic scaling

2012-01-21T00:00:00Z

A mathematical classification of conservation prioritization problems

2010-03-22T00:00:00Z

A meandering pathway to a veterinary career in academia and research

Norman, S.T. — 2007-08-23T00:00:00Z

A Megaraptor-like theropod (Dinosauria: Tetanurae) in Australia: support for faunal exchange across eastern and western Gondwana in the Mid-Cretaceous

2008-11-27T00:00:00Z

A Method for Capturing Dugongs (Dugong dugon) in Open Water

2007-08-15T00:00:00Z

We developed a method to rapidly and safely live capture wild dugongs based on the “rodeo method” employed to catch marine turtles. This method entails close pursuit of a dugong by boat until it is fatigued. The dugong is then caught around the peduncle region by a catcher leaping off the boat, and the dugong is restrained at the water surface by several people while data are collected. Our sampling protocol involves a short restraint time, typically < 5 min. No ropes or nets were attached to the dugong to avoid the risk of entanglement and subsequent drowning. This method is suitable for shallow, open-water captures when weather and water conditions are fair, and may be adapted for deeper waters.

A method for facilitating pathogen resistance

2007-10-09T00:00:00Z

A method for setting the size of plant conservation target areas

2007-08-13T00:00:00Z

Realistic time frames in which management decisions are made often preclude the completion of the detailed analyses necessary for conservation planning. Under these circumstances, efficient alternatives may assist in approximating the results of more thorough studies that require extensive resources and time. We outline a set of concepts and formulas that may be used in lieu of detailed population viability analyses and habitat modeling exercises to estimate the protected areas required to provide desirable conservation outcomes for a suite of threatened plant species. We used expert judgment of parameters and assessment of a population size that results in a specified quasiextinction risk based on simple dynamic models The area required to support a population of this size is adjusted to take into account deterministic and stochastic human influences, including small-scale disturbance deterministic trends such as habitat loss, and changes in population density through processes such as predation and competition. We set targets for different disturbance regimes and geographic regions. We applied our methods to Banksia cuneata, Boronia keysii, and Parsonsia dorrigoensis, resulting in target areas for conservation of 1102, 733, and 1084 ha, respectively. These results provide guidance on target areas and priorities for conservation strategies.

A method of sampling blood from Australian freshwater turtles

Rogers, K. D. og Booth, D. T. — 2007-08-15T00:00:00Z

Blood sampling is an essential technique in many herpetological studies. This paper describes a quick and humane technique to collect blood samples from three species of Australian chelid turtles ( Order Pleurodira): Chelodina expansa, Elseya latisternum, and Emydura macquarii signata.

A mitochondrial phylogeny of the rainforest skink genus Saproscincus, Wells and Wellington (1984)

2007-08-15T00:00:00Z

The phylogenetic relationships and historical biogeography of 10 currently described rainforest skinks in the genus Saproscincus were investigated using mitochondrial protein-coding ND4 and ribosomal RNA 16S genes. A robust phylogeny is inferred using both maximum likelihood and Bayesian analysis, with all inter-specific nodes strongly supported when datasets are combined. The phylogeny supports the recognition of two major lineages (northern and southern), each of which comprises two divergent clades. Both northern and southern lineages have comparably divergent representatives in mid-east Queensland (MEQ), providing further molecular evidence for the importance of two major biogeographic breaks, the St. Lawrence gap and Burdekin gap separating MEQ from southern and northern counterparts respectively. Vicariance associated with the fragmentation and contraction of temperate rainforest during the mid-late Miocene epoch underpins the deep divergence between morphologically conservative lineages in at least three instances. In contrast, one species, Saproseincus oriarus, shows very low sequence divergence but distinct morphological and ecological differentiation from its allopatric sister clade within Saproseincus mustelinus. These results suggest that while vicariance has played a prominent role in diversification and historical biogeography of Saproscincus, divergent selection may also be important. (C) 2004 Elsevier Inc. All rights reserved.

A Mixed Model Approach to Identify Yeast Transcriptional Regulatory Motifs via Microarray Experiments

2009-03-05T00:00:00Z

A genome-wide location analysis method has been introduced as a means to simultaneously study protein-DNA binding interactions for a large number of genes on a microarray platform. Identification of interactions between transcription factors (TF) and genes provide insight into the mechanisms that regulate a variety of cellular responses. Drawing proper inferences from the experimental data is key to finding statistically significant TF-gene binding interactions. We describe how the analysis and interpretation of genome-wide location data can be fit into a traditional statistical modeling framework that considers the data across all arrays and formulizes appropriate hypothesis tests. The approach is illustrated with data from a yeast transcription factor binding experiment that illustrates how identified TF-gene interactions can enhance initial exploration of transcriptional regulatory networks. Examples of five kinds of transcriptional regulatory structure are also demonstrated. Some stark differences with previously published results are explored.

A model-based approach to determine the long term effects of multiple interacting stressors on coral reef

2011-10-18T00:00:00Z

The interaction between multiple stressors on Caribbean coral reefs, namely, fishing effort and hurricane impacts, is a key element in the future sustainability of reefs. We develop an analytic model of coral–algal interactions and explicitly consider grazing by herbivorous reef fish. Further, we consider changes in structural complexity, or rugosity, in addition to the direct impacts of hurricanes, which are implemented as stochastic jump processes. The model simulations consider various levels of fishing effort corresponding to several hurricane frequencies and impact levels dependent on geographic location. We focus on relatively short time scales so we do not explicitly include changes in ocean temperature, chemistry, or sea level rise. The general features of our approach would, however, apply to these other stressors and to the management of other systems in the face of multiple stressors. It is determined that the appropriate management policy, either local reef restoration or fisheries management, greatly depends on hurricane frequency and impact level. For sufficiently low hurricane impact and macroalgal growth rate, our results indicate that regions with lower-frequency hurricanes require stricter fishing regulations, whereas management in regions with higher-frequency hurricanes might be less concerned with enhancing grazing and instead consider whether local-scale restorative activities to increase vertical structure are cost-effective.

A model-framed evaluation of elephant effects on tree and fire dynamics in African savannas

Baxter, P. W. J. og Getz, W. M. — 2008-01-25T00:00:00Z

There is a concern that high densities of elephants in southern Africa could lead to the overall reduction of other forms of biodiversity. We present a grid-based model of elephant-savanna dynamics, which differs from previous elephant-vegetation models by accounting for woody plant demographics, tree-grass interactions, stochastic environmental variables (fire and rainfall), and spatial contagion of fire and tree recruitment. The model projects changes in height structure and spatial pattern of trees over periods of centuries. The vegetation component of the model produces long-term tree-grass coexistence, and the emergent fire frequencies match those reported for southern African savannas. Including elephants in the savanna model had the expected effect of reducing woody plant cover, mainly via increased adult tree mortality, although at an elephant density of 1.0 elephant/km(2), woody plants still persisted for over a century. We tested three different scenarios in addition to our default assumptions. (1) Reducing mortality of adult trees after elephant use, mimicking a more browsing-tolerant tree species, mitigated the detrimental effect of elephants on the woody population. (2) Coupling germination success (increased seedling recruitment) to elephant browsing further increased tree persistence, and (3) a faster growing woody component allowed some woody plant persistence for at least a century at a density of 3 elephants/km(2). Quantitative models of the kind presented here provide a valuable tool for exploring the consequences of management decisions involving the manipulation of elephant population densities.

A modelling approach to estimate the effect of exotic pollinators on exotic weed population dynamics: bumblebees and broom in Australia

2007-08-15T00:00:00Z

The role of mutualisms in contributing to species invasions is rarely considered, inhibiting effective risk analysis and management options. Potential ecological consequences of invasion of non-native pollinators include increased pollination and seed set of invasive plants, with subsequent impacts on population growth rates and rates of spread. We outline a quantitative approach for evaluating the impact of a proposed introduction of an invasive pollinator on existing weed population dynamics and demonstrate the use of this approach on a relatively data-rich case study: the impacts on Cytisus scoparius (Scotch broom) from proposed introduction of Bombus terrestris. Three models have been used to assess population growth (matrix model), spread speed (integrodifference equation), and equilibrium occupancy (lattice model) for C. scoparius. We use available demographic data for an Australian population to parameterize two of these models. Increased seed set due to more efficient pollination resulted in a higher population growth rate in the density-independent matrix model, whereas simulations of enhanced pollination scenarios had a negligible effect on equilibrium weed occupancy in the lattice model. This is attributed to strong microsite limitation of recruitment in invasive C. scoparius populations observed in Australia and incorporated in the lattice model. A lack of information regarding secondary ant dispersal of C. scoparius prevents us from parameterizing the integrodifference equation model for Australia, but studies of invasive populations in California suggest that spread speed will also increase with higher seed set. For microsite-limited C. scoparius populations, increased seed set has minimal effects on equilibrium site occupancy. However, for density-independent rapidly invading populations, increased seed set is likely to lead to higher growth rates and spread speeds. The impacts of introduced pollinators on native flora and fauna and the potential for promoting range expansion in pollinator-limited 'sleeper weeds' also remain substantial risks.

A modest proposal for wealthy countries to reforest their land for the common good

Meijaard, Erik og Sheil, Douglas — 2011-09-25T00:00:00Z

We discuss a recent press release calling on wealthy countries to do more to combat climate change and protect their biodiversity. We examine some further examples of how questionable views are imposed unilaterally on conservation problems. Until we better engage with local perspectives we shall be less credible and less effective as conservationists.

A molecular clock based on the expansion of gene families

Trusov, Y. A. og Dear, P. H. — 2010-07-20T09:02:03Z

There is evidence to suggest that eukaryotic genomes are subject to frequent insertions and deletions of non-coding DNA. This may lead to a gradual increase or decrease in genome size, or to a dynamic equilibrium in which the overall size remains constant. We argue, however, that there is a bias favouring an accumulation of non-coding DNA in the proximity of genes. Such bias causes a progressive change in genome structure regardless of whether the overall genome size increases, decreases or remains constant. We show that this change may serve as a 'molecular clock', supplementing that provided by nucleotide substitution rates.

A molecular method for the detection of prey in the guts of clubionidae spiders

Pearce, S. og Zalucki, M. P. — 2007-08-24T00:00:00Z

A molecular perspective on the conservation of diversity

Moritz, C. C. — 2008-06-06T00:00:00Z

A molecular phylogeny for the frog genus Limnodynastes (Anura:myobatrachidae)

Schauble, C. og Moritz, C. C. og Slade, R. — 2008-06-10T00:00:00Z

A molecular phylogeny for the Tribe Dacini (Diptera: Tephritidae): Systematic and biogeographic implications

2012-09-02T00:21:04Z

With well over 700 species, the Tribe Dacini is one of the most species-rich clades within the dipteran family Tephritidae, the true fruit flies. Nearly all Dacini belong to one of two very large genera, Dacus Fabricius and Bactrocera Macquart. The distribution of the genera overlap in or around the Indian subcontinent, but the greatest diversity of Dacus is in Africa and the greatest diversity of Bactrocera is in south-east Asia and the Pacific. The monophyly of these two genera has not been rigorously established, with previous phylogenies only including a small number of species and always heavily biased to one genus over the other. Moreover, the subgeneric taxonomy within both genera is complex and the monophyly of many subgenera has not been explicitly tested. Previous hypotheses about the biogeography of the Dacini based on morphological reviews and current distributions of taxa have invoked an out-of-India hypothesis; however this has not been tested in a phylogenetic framework. We attempted to resolve these issues with a dated, molecular phylogeny of 125 Dacini species generated using 16S, COI, COII and white eye genes. The phylogeny shows that Bactrocera is not monophyletic, but rather consists of two major clades: Bactrocera s.s. and the 'Zeugodacus group of subgenera' (a recognised, but informal taxonomic grouping of 15 Bactrocera subgenera). This 'Zeugodacus' clade is the sister group to Dacus, not Bactrocera and, based on current distributions, split from Dacus before that genus moved into Africa. We recommend that taxonomic consideration be given to raising Zeugodacus to genus level. Supportive of predictions following from the out-of-India hypothesis, the first common ancestor of the Dacini arose in the mid-Cretaceous approximately 80. mya. Major divergence events occurred during the Indian rafting period and diversification of Bactrocera apparently did not begin until after India docked with Eurasia (50-35. mya). In contrast, diversification in Dacus, at approximately 65. mya, apparently began much earlier than predicted by the out-of-India hypothesis, suggesting that, if the Dacini arose on the Indian plate, then ancestral Dacus may have left the plate in the mid to late Cretaceous via the well documented India-Madagascar-Africa migration route. We conclude that the phylogeny does not disprove the predictions of an out-of-India hypothesis for the Dacini, although modification of the original hypothesis is required.

A Molecular Phylogeny of Phytophthora and Related Oomycetes

2008-06-10T00:00:00Z

Phylogenetic relationships among 50 Phytophthora species and between Phytophthora and other oomycetes were examined on the basis of the ITS sequences of genomic rDNA. Phytophthora grouped with Pythium, Peronospora, and Halophytophthora, distant from genera in the Saprolegniales. Albugo was intermediate between these two groups, Unlike Pythium, Phytophthora was essentially monophyletic, all but three species forming a cluster of eight clades, Two clades contained only species with nonpapillate sporangia, The other six clades included either papillate and semipapillate, or semipapillate and nonpapillate types, transcending traditional morphological groupings, which are evidently not natural assemblages, Peronospora was related to P, megakarya and P, palmivora and appears to be derived from a Phytophthora that has both lost the ability to produce zoospores and become an obligate biotroph, Three other Phytophthoras located some distance from the main Phytophthora-Peronospora cluster probably represent one or more additional genera, (C) 2000 Academic Press.

A molecular phylogeny of rainbow skinks (Scincidae : Carlia): taxonomic and biogeographic implications

2007-08-14T00:00:00Z

The phylogenetic relationships amongst 29 species of Carlia and Lygisaurus were estimated using a 726-base-pair segment of the protein-coding mitochondrial ND4 gene. Results do not support the recent resurrection of the genus Lygisaurus. Although most Lygisaurus species formed a single clade, this clade is nested within Carlia and includes Carlia parrhasius. Due to this new molecular evidence, and the paucity of diagnostic morphological characters separating the genera, Lygisaurus de Vis 1884 is re-synonymised with Carlia Gray 1845. Our analysis is also inconsistent with a previous suggestion that Lygisaurus timlowi should be removed to Menetia, a genus that is distantly related relative to outgroups used here. Intraspecific variation in Carlia is, in several instances, greater than interspecific distance. The most strikingly divergent lineages are found within C. rubrigularis, which appears to be paraphyletic, with southern populations more closely related to C. rhomboidalis than to northern populations of C. rubrigularis. The two C. rubrigularis-C. rhomboidalis lineages form part of a major polytomy at an intermediate level of divergence. Lack of resolution at this level, however, does not appear to be due to saturation or loss of phylogenetic signal. Rather, the polytomy probably reflects a period of relatively rapid diversification that occurred sometime during the Miocene.

A molecular phylogeny of the Australian skink genera Eulamprus, Gnypetoscincus and Nangura

O'Connor, D. og Moritz, C. C. — 2007-08-15T00:00:00Z

Skinks from the genera Eulamprus, Gnypetoscincus and Nangura are a prominent component of the reptile fauna of the mesic forests of the east coast of Australia and have been the subject of numerous ecological studies. Highly conserved morphology and the retention of ancestral traits have limited our understanding of the relationships within and among these genera beyond an initial identification of species groups within Eulamprus. To address this deficit and to explore the relationships between Eulamprus and the monotypic genera Nangura and Gnypetoscincus, sections of two mitochondrial genes (ND4 and 16S rRNA) were sequenced and subjected to Bayesian phylogenetic analysis. This phylogenetic analysis supports recognition of the three species groups proposed for Eulamprus (murrayi, quoyii and tenuis) and indicates that this genus is paraphyletic, with Gnypetoscincus and Nangura being proximal to basal lineages of the tenuis group. To resolve these and broader problems of paraphyly, we suggest that each of the species groups from 'Eulamprus' should be recognised as a distinct genus. The phylogenetically and ecologically distinct water skinks of the quoyii group would be retained within Eulamprus and the diverse species of the tenuis group allocated to Concinnia. We suggest placing the monophyletic murrayi group, endemic to the rainforests of central eastern Australia, in a new genus ( yet to be formally described). The sequencing data also revealed the existence of a genetically divergent but morphologically cryptic lineage within E. murrayi and substantial diversity within E. quoyii. There is evidence for two major habitat shifts from rainforest towards drier habitats, one leading to the quoyii group and the second defining a clade of three species within the tenuis complex. These ecological transitions may represent adaptations to general drying across eastern Australia during the late Miocene - Pliocene. Each of the major areas of east coast tropical or subtropical rainforest contains multiple phylogenetically diverse endemic species, reflecting the long-term persistence and high conservation value of wet forest habitats in each area.

A molecular taxonomy for cricket paralysis virus including two new isolates from Australian populations ofDrosophila

Johnson, K. N. og Christian, P. D. — 2009-01-07T00:00:00Z

Two new isolates of cricket paralysis virus, TAR and SIM, are described that were originally isolated from laboratory colonies ofDrosophila melanogaster andDrosophila simulans respectively. Using a combination of biological, serological and molecular characters it was possible to distinguish the SIM isolate from all other isolates and it is thus described as a new strain; CrPVSIM. The TAR isolate however, was indistinguishable from the CrPV reference isolate CrPVVIC/Gm/D22/Gm/D22 (Teleogryllus commodus, Victoria, Australia, 1968). The molecular characters used in the present study were obtained by combining PCR and restriction endonuclease digestion of the amplified fragments. This work demonstrates that such molecular characters, when used in combination with others, provide a powerful set of taxonomic characters for classifying CrPV isolates and strains and assessing their genetic relatedness

A morphological study of the Anopheles punctulatus group (Diptera: Culicidae) in the Solomon Islands, with a description of Anopheles (Cellia) irenicus Schmidt, sp.n.

2007-08-15T00:00:00Z

A description of Anopheles (Cellia) irenicus Schmidt, sp.n. (formerly A. farauti No. 7) is provided. This species is one of six recorded from the Solomon Islands within the A. punctulatus group, which contains the major vectors of the causative agents of malaria and lymphatic filariasis in the southwest Pacific. Morphological markers are described for adult females, fourth-instar larvae and pupae that identify most specimens of A. irenicus. Keys are presented to distinguish members of the A. punctulatus group in the Solomon Islands.

A mosquito densovirus infecting Aedes aegypti and Aedes albopictus from Thailand

2007-04-13T00:00:00Z

A previously undescribed mosquito densovirus was detected in colonies of Aedes aegypti and Ae. albopictus from Thailand, using a polymerase chain reaction (PCR)-based assay. Phylogenetic analysis of this virus showed it to be most closely related to ADNV isolated from Russian Ae. aegypti. Both Aedes species were susceptible to oral infection with the Thai-strain virus. Larval mortality for Ae. albopictus was higher (82%) than for Ae. aegypti (51%). Aedes aegypti were able to transmit the virus vertically to a high (58%) proportion of G1 progeny, and the virus was maintained persistently for up to six generations. A PCR survey of adult Ae. aegypti and Ae. albopictus in Thailand indicated that only Ae. aegypti are infected in the field, with an overall prevalence of 44%. Densovirus infection in adult Ae. aegypti showed distinct seasonal variation. The Thai strain densovirus may play a role in structuring Ae. albopictus and Ae. aegypti populations in nature.

A Mox homeobox gene in the gastropod mollusc Haliotis rufescens is differentially expressed during larval morphogenesis and metamorphosis

2007-08-13T00:00:00Z

We have isolated a homeobox-containing cDNA from the gastropod mollusc Haliotis rufescens that is most similar to members of the Mox homeobox gene class, The derived Haliotis homeodomain sequence is 85% identical to mouse and frog Mox-2 homeodomains and 88.9% identical to the partial cnidarian cnox5-Hm homeodomain. Quantitative reverse transcription-polymerase chain reaction analysis of mRNA accumulation reveals that this gene, called HruMox, is expressed in the larva, but not in the early embryo, Transcripts are most prevalent during larval morphogenesis from trochophore to veliger. There are also transient increases in transcript prevalence 1 and 3 days after the intitiation of metamorphosis from veliger to juvenile. The identification of a molluscan Mox homeobox gene that is more closely related to vertebrate genes than other protostome (e.g. Drosophila) genes suggests the Mox class of homeobox genes may consist of several different families that have been conserved through evolution, (C) 1997 Federation of European Biochemical Societies.

A multifunctional polyketide-peptide synthetase essential for albicidin biosynthesis in Xanthomonas albilineans

2007-08-14T00:00:00Z

Albicidins, a family of potent antibiotics and phytotoxins produced by the sugarcane leaf scald pathogen Xanthomonas albilineans, inhibit DNA replication in bacteria and plastids. A gene located by Tn5-tagging was confirmed by complementation to participate in albicidin biosynthesis. The gene (xabB) encodes a large protein (predicted Mr 525695), with a modular architecture indicative of a multifunctional polyketide synthase (PKS) linked to a non-ribosomal peptide synthetase (NRPS). At 4801 amino acids in length, XabB is the largest reported PKS–NRPS. Twelve catalytic domains in this multifunctional enzyme are arranged in the order N terminus–acyl-CoA ligase (AL)–acyl carrier protein (ACP)–ß-ketoacyl synthase (KS)–ß-ketoacyl reductase (KR)–ACP–ACP–KS–peptidyl carrier protein (PCP)–condensation (C)–adenylation–PCP–C. The modular architecture of XabB indicates likely steps in albicidin biosynthesis and approaches to enhance antibiotic yield. The novel pattern of domains, in comparison with known PKS–NRPS enzymes for antibiotic production, also contributes to the knowledge base for rational design of enzymes producing novel antibiotics.

A multilocus coalescent analysis of the speciational history of the Australo-Papuan butcherbirds and their allies

2013-02-02T11:00:47Z

Changes in geology, sea-level and climate are hypothesised to have been major driving processes of evolutionary diversification (speciation and extinction) in the Australo-Papuan region. Here we use complete species-level sampling and multilocus (one mitochondrial gene, five nuclear loci) coalescent analyses to estimate evolutionary relationships and test hypotheses about the role of changes in climate and landscape in the diversification of the Australo-Papuan butcherbirds and allies (Cracticinae: Cracticus, Strepera, Peltops). Multilocus species trees supported the current classification of the morphologically, ecologically and behaviourally divergent Australian Magpie (Cracticus tibicen (previously Gymnorhina tibicen)) as a member of an expanded genus Cracticus, which includes seven other species with 'butcherbird' morphology and behaviour. Non-monophyly of currently recognised species within Peltops and the white-throated butcherbird species-group (C. argenteus, C. mentalis, C. torquatus) at both mtDNA and nuclear loci suggest that a comprehensive taxonomic revision is warranted for both of these groups. The time-calibrated multilocus species tree revealed an early divergence between the New Guinean rainforest-restricted Peltops lineage and the largely open-habitat inhabiting Cracticus (butcherbirds and magpies) plus Strepera (currawongs) lineage around 17-28 Ma, as well as a relatively recent radiation of lineages within Cracticus over the past 8 Ma. Overall, patterns and timings of speciation were consistent with the hypothesis that both the expansion of open sclerophyllous woodlands 25-30 Ma and the formation of extensive grassland-dominated woodlands 6-8 Ma allowed the radiation of lineages adapted to open woodland habitats.

A multilocus perspective on refugial isolation and divergence in rainforest skinks (Carlia)

Dolman, G. og Moritz, C. — 2007-08-15T00:00:00Z

To explore the evolutionary consequences of climate-induced fluctuations in distribution of rainforest habitat we contrasted demographic histories of divergence among three lineages of Australian rainforest endemic skinks. The red-throated rainbow skink, Carlia rubrigularis, consists of morphologically indistinguishable northern and southern mitochondrial DNA (mtDNA) lineages that are partially reproductively isolated at their parapatric boundary. The third lineage (C. rhomboidalis) inhabits rainforests just to the south of C. rubrigularis, has blue, rather than red-throated males, and for mtDNA is more closely related to southern C. rubrigularis than is northern C. rubrigularis. Multigene coalescent analyses supported more recent divergence between morphologically distinct lineages than between morphologically conservative lineages. There was effectively no migration and therefore stronger isolation between southern C. rubrigularis and C. rhomboidalis, and low unidirectional migration between morphologically conservative lineages of C. rubrigularis. We found little or no evidence for strong differences in effective population size, and hence different contributions of genetic drift in the demographic history of the three lineages. Overall the results suggest contrasting responses to long-term fluctuations in rainforest habitats, leading to varying opportunities for speciation.

A mutational analysis of branching in pea identifies roles for novel long-distance signals

2008-06-06T00:00:00Z

An addition to the rainbowfish (Melanotaeniidae) fauna of North Queensland

McGuigan, Katrina Louise — 2009-01-12T00:00:00Z

A new Melanotaeniid species is described from 28 specimens collected from the Johnstone River, north Queensland. Melanotaenia utcheensis sp. nov. was found in sites with moderate to high water flow over cobbles and boulders and all sites are in close proximity to major agricultural activity and have moderately to highly disturbed riparian vegetation. Melanotaenia utcheensis sp. nov. has a distinctive colour pattern with a blue-black mid-lateral band and orange margins on vertical scale rows. It is morphologically distinct from the broadly sympatric Melanotaenia eachamensis (Allen & Cross, 1982) and Melanotaenia splendida splendida (Peters, 1866), as well as from its sister species from southern Queensland/northern New South Wales, Melanotaenia duboulayi (Castelnau, 1878). In particular, M. utcheensis sp. nov. has more first dorsal spines and fewer vertical scale rows and anal rays than M. s. splendida, and fewer soft second dorsal rays and more pectoral rays than either M. eachamensis or M. duboulayi. The new species is also generally smaller than either M. s. splendida or M. eachamensis and intermediate between them in eye diameter, predorsal length, head depth and body depth.

An Aerial Survey of Potential Nesting Areas of Crocodylus porosus on the West Coast of Cape York Peninsula

2004-12-06T00:00:00Z

This paper presents the results of an aerial survey for potential nesting areas of C. porosus along the western coast of Cape York Peninsula, Queensland, from the tip of the Cape to the Norman River. There is a decrease from north to south in the amount of suitable nesting habitat. Many suitable nesting areas occur north of the Embley River, where relatively higher relief favours the development of freshwater swamps with a low risk of seasonal flooding. Further south, the broad, alluvial plains and meandering rivers are often subject to extensive flooding and fewer opportunities for nesting are available. General conclusions only are given, and management discussed. Detailed results are lodged with the Australian National Library, Canberra (catalogue no. MS5640).

An Aerial Survey of Potential Nesting Areas of the Saltwater Crocodile, Crocodylus porosus Schneider, on the North Coast of Arnhem Land, Northern Australia

2004-12-06T00:00:00Z

Results of a study of habitats used by C. porosus for nesting on the Liverpool and Tonkinson Rivers, Arnhem land, northern Australia, are presented. These were used as the basis of an aerial survey for potential crocodile nesting habitat in coastal wetlands between Smith point (Cobourg peninsula) and Gove. General conclusions of the survey are given, and areas in which different types of management could be applied are indicated. Detailed results are lodged with the Australian National Library, Canberra (catalogue no. MS5640).

An aggregative response of the tropical Australian magpie goose (Anseranas semipalmata) to seasonal floodplains

Traill, Lochran W. og Brook, Barry W. — 2011-03-13T00:00:00Z

An alternative method for predicting body mass: the case of the Pleistocene marsupial lion

2007-08-15T00:00:00Z

Accurate estimates of body mass in fossil taxa are fundamental to paleobiological reconstruction. Predictive equations derived from correlation with craniodental and body mass data in extant taxa are the most commonly used, but they can be unreliable for species whose morphology departs widely from that of living relatives. Estimates based on proximal limb-bone circumference data are more accurate but are inapplicable where postcranial remains are unknown. In this study we assess the efficacy of predicting body mass in Australian fossil marsupials by using an alternative correlate, endocranial volume. Body mass estimates for a species with highly unusual craniodental anatomy, the Pleistocene marsupial lion (Thylacoleo carnifex), fall within the range determined on the basis of proximal limb-bone circumference data, whereas estimates based on dental data are highly dubious. For all marsupial taxa considered, allometric relationships have small confidence intervals, and percent prediction errors are comparable to those of the best predictors using craniodental data. Although application is limited in some respects, this method may provide a useful means of estimating body mass for species with atypical craniodental or postcranial morphologies and taxa unrepresented by postcranial remains. A trend toward increased encephalization may constrain the method's predictive power with respect to many, but not all, placental clades.

Analysing the generality of spatially predictive mosquito habitat models

2011-09-02T00:00:00Z

Analysis of Cell Movement in Amphimedon Embryos by Injection of Fluorescent Tracers

Adamska, Maja og Degnan, Bernard M. — 2009-02-13T00:00:00Z

Analysis of differential gene expression during the semi-lunar reproductive cycle of Haliotis asinina

2007-08-24T00:00:00Z

Analysis of early life history stages of the saucer scallop Amusium balloti (Bernardi, 1861) : impacts on the development of hatchery practices

Wang, Sizhong — 2008-11-21T00:00:00Z

Analysis of environmental factors influencing the range of anopheline mosquitoes in northern Australia using a genetic algorithm and data mining methods

2009-02-26T00:00:00Z

Environmental factors which influence the distributions of malaria vectors in northern Australia (Anopheles farauti ss, A. farauti 2 and A. farauti 3) were investigated by ecological niche modelling and data mining using an extensive data set of species presence and absence records obtained by systematic field surveys. Models were generated with GARP (the genetic algorithm for rule-set prediction) using geographical coverages of 41 climatic and topographic parameters for the north of the continent. Environmental variables associated with species records were identified with the ranking procedures of the decision tree software packages CART and KnowledgeSeeker. There was consistent agreement in the variables ranked by both methods. This permitted the selection of reduced sets of environmental variables to develop GARP models for the three target species with equivalent predictive accuracy to those which used all of the environmental information. The environmental parameters which define the realised distributions of A. farauti ss and A. farauti 3 were well described by this approach but the results were less satisfactory for A. farauti 2. Atmospheric moisture was shown to be a critical variable for each species which accords with many field and laboratory observations concerning the influence of humidity on adult mosquito survival..

Analysis of evolutionarily conserved innate immune components in coral links immunity and symbiosis

2010-11-05T00:00:00Z

Analysis of evolutionary, biogeographical and taxonomic patterns of nucleotide composition in demosponge rRNA

2008-04-15T00:00:00Z