989 resultados para Northern Pacific Railway
Resumo:
Whereas terrestrial animal populations might show genetic connectivity within a continent, marine species, such as hermatypic corals, may have connectivity stretching to all corners of the planet. We quantified the genetic variability within and among populations of the widespread scleractinian coral, Plesiastrea versipora along the eastern Australian seaboard (4145 km) and the Ryukyu Archipelago (Japan, 681 km) using sequences of internal transcribed spacers (ITS1-2) from ribosomal DNA. Geographic patterns in genetic variability were deduced from a nested clade analysis (NCA) performed on a parsimony network haplotype. This analysis allowed the establishment of geographical associations in the distribution of haplotypes within the network cladogram, therefore allowing us to deduce phylogeographical patterns based under models of restricted gene flow, fragmentation and range expansion. No significant structure was found among Ryukyu Archipelago populations. The lack of an association between the positions of haplotypes in the cladogram with geographical location of these populations may be accounted for by a high level of gene flow of P. versipora within this region, probably due to the strong Kuroshio Current. In contrast, strong geographical associations were apparent among populations of P. versipora along the south-east coast of Australia. This pattern of restricted genetic connectivity among populations of P. versipora on the eastern seaboard of Australia seems to be associated with the present surface ocean current (the East Australian Current) on this side of the south-western Pacific Ocean.
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The members of the Anopheles punctulatus group are major vectors of malaria and Bancroftian filariasis in the southwest Pacific region. The group is comprised of 12 cryptic species that require DNA-based tools for species identification. From 1984 to 1998 surveys were carried out in northern Australia, Papua New Guinea and on islands in the southwest Pacific to determine the distribution of the A. punctulatus group. The results of these surveys have now been completed and have generated distribution data from more than 1500 localities through this region. Within this region several climatic and geographical barriers were identified that restricted species distribution and gene flow between geographic populations. This information was further assessed in light of a molecular phylogeny derived from the ssrDNA (18S). Subsequently, hypotheses have been generated on the evolution and distribution of the group so that future field and laboratory studies may be approached more systematically. This study suggested that the ability for widespread dispersal was found to have appeared independently in species that show niche-specific habitat preference (Anopheles farauti s.s. and A. punctulatus) and conversely in species that showed diversity in their larval habitat (Anopheles farauti 2). Adaptation to the monsoonal climate of northern Australia and southwest Papua New Guinea was found to have appeared independently in A. farauti s.s., A. farauti 2 and Anopheles farauti 3. Shared or synapomorphic characters were identified as saltwater tolerance (A. farauti s.s. and Anopheles farauti 7) and elevational affinities above 1500 m (Anopheles farauti 5, Anopheles farauti 6 and A. farauti 2). (C) 2002 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.
Resumo:
Streptococcus pyogenes (Group A streptococcus) interacts with host fibronectin via a number of distinct surface components. The streptococcal serum opacity factor (SOF) is a cell-surface protein of S. pyogenes which opalescence of human serum and mediates bacterial binding to fibronectin. In this study, hexahistidyl-tagged fusion proteins encompassing full-length SOF, and domains of SOF encompassing opacity factor activity and fibronectin-binding regions, were used in the characterization of the Aboriginal immune response to SOF. Anti-SOF serum IgG responses were found to be significantly higher (P
Resumo:
Objective To describe the clinical signs, gross pathology, serology, bacteriology, histopathology, electron microscopy and immunohistochemistry findings associated with toxoplasmosis in four Indo-Pacific humpbacked dolphins (Sousa chinensis) that stranded in Queensland in 2000 and 2001. Design Clinical assessment, gross necropsy, and laboratory examinations. Procedure Necropsies were performed on four S chinensis to determine cause of death. Laboratory tests including serology, bacteriology, histopathology and transmission electron microscopy were done on the four dolphins. Immunohistochemistry was done on the brain, heart, liver, lung, spleen and adrenal gland from various dolphins to detect Toxoplasma gondii antigens. Results Necropsies showed all of four S chinensis that stranded in Queensland in 2000 and 2001 had evidence of predatory shark attack and three were extremely emaciated. Histopathological examinations showed all four dolphins had toxoplasmosis with tissue cysts resembling T gondii in the brain. Tachyzoite stages of T gondii were detected in the lungs, heart, liver, spleen and adrenal gland, variously of all four dolphins. Electron microscopy studies and immunohistochemistry confirmed the tissues cysts were those of T gondii. All four dolphins also had intercurrent disease including pneumonia, three had peritonitis and one had pancreatitis. Conclusion Four S chinensis necropsied in Queensland in 2000 and 2001 were found to be infected with toxoplasmosis. It is uncertain how these dolphins became infected and further studies are needed to determine how S chinensis acquire toxoplasmosis. All four dolphins stranded after periods of heavy rainfall, and coastal freshwater runoff may be a risk factor for T gondii infection in S chinensis. This disease should be of concern to wildlife managers since S chinensis is a rare species and its numbers appear to be declining.
Resumo:
Two new species of lepocreadiid trematodes are described from teleost fishes from off the coast of northern Tasmania. Opechona kahawai sp. nov. from Arripis sp. (Arripidae) differs from congeners by a combination of a longer prepharynx, longer excretory vesicle and the genital pore antero-sinistral to the ventral sucker. Cephalolepidapedon warehou sp. nov. from Seriolella punctata (Centrolophidae) differs from its only congener in the vitellarium reaching into the posterior forebody, a heavy concentration of eye-spot pigment in the forebody, a relatively narrower and more elongate body, a longer prepharynx and a more distinct oesophagus.
Resumo:
Much is known about those aspects of tuna health which can be studied in wild populations, e.g. helminth parasites. However, because aquaculture of these species is in its infancy, knowledge of microbial, nutritional and environmental diseases is limited. This review is an attempt to bring together the available information on those diseases of Thunnus spp. which cause significant morbidity, mortality or economic loss. In doing so it has become clear that much more research needs to be undertaken on the physiology of the species (southern, northern and Pacific bluefin tuna) currently used in aquaculture in order for the pathogenesis of some conditions to be properly understood. Attempts at hatchery culture of Pacific bluefin tuna has indicated that Thunnus spp. will be problematic to hatch and propagate.
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Nine species of Stephanostomum are described from Australian and Southern Pacific marine fishes: Stephanostomum madhaviae n. sp. [syn. S. orientalis of Madhavi ( 1976)] from Caranx ignobilis, off Hope Island, Queensland, with 30-34 circum-oral spines and vitelline fields almost reaching to the posterior extremity of the cirrus-sac; S. bicoronatum (Stossich, 1883) from Argyrosomus hololepidotus, off Southport Broadwater, Queensland; S. votonimoli n. sp. from Scomberoides lysan, off Moorea, French Polynesia ( type-locality) and Western Samoa, with 33-38 circum-oral spines, a uroproct and the vitelline fields not reaching the cirrus-sac; S. nyoomwa n. sp. from Caranx sexfasciatus, off Heron Island, Queensland, with 33-38 circum-oral spines, a uroproct and the vitelline fields reaching the cirrus-sac; S. cobia n. sp. from Rachycentron canadum, off Heron Island, with 36 circum-oral spines, a uroproct and the vitelline fields reaching the cirrus-sac; S. petimba Yamaguti, 1970 from Seriola hippos, off Rottnest Island, Western Australia; S. pacificum ( Yamaguti, 1951) from Pseudocaranx wrighti, off Fremantle, Western Australia; S. aaravi n. sp. from Lethrinus miniatus, off Heron Island, with 36-39 circumoral spines, probably a uroproct and the vitelline fields reaching the ventral sucker; S. pagrosomi ( Yamaguti, 1939) from L. nebulosus, L. miniatus and L. atkinsoni off Heron Island, Pagrus auratus, off Rottnest Island, Western Australia and Gymnocranius audleyi, off Heron Island. A digest of described species of Stephanostomum is included as an appendix.
Resumo:
Intraerythrocytic bodies identified as haemogregarine gamonts were found in 29% of 97 brown tree snakes (Boiga irregularis) examined during a haematological survey of reptiles in Australasia during 1994-1998. The morphological characteristics of the parasites were consistent with those of Haemogregarina boigae Mackerras, 1961, although the gamonts were slightly larger and lacked red caps but contained distinctive polar grey capsules. Gamonts did not distend host cells but laterally displaced their nuclei. They were contained within parasitophorous vacuoles and possessed typical apicomplexan organelles, including a conoid, polar rings, rhoptries and micronemes. Schizonts producing up to 30 merozoites were detected in endothelial cells of the lungs of 11 snakes. The absence of erythrocytic schizogony suggests the parasites belong to the genus Hepatozoon. Electron microscopy also revealed the presence of curious encapsulated organisms in degenerating erythrocytes. These stages did not possess apical complex organelles and were surrounded by thick walls containing circumferential junctions and interposed strips reminiscent of oocyst sutures.
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The parasite fauna of Spanish mackerel Scomberomorus commerson from 10 sites across northern Australia and one site in Indonesia, was examined to evaluate the degree of movement and subsequent stock structure of the fish. Kupang fish (Indonesia) had very few Terranova spp.. Grillotia branchi, Otobothrium cysticum or Pterobothrium sp. compared to Australian fish, indicating that no Australian fish enter the Kupang fishery. Univariate and discriminant function analysis of four 'temporary' parasite species, the copepod Pseudocyenoides armatus and the monogeneans Gotocotyla bivaginalis, Pricea multae and Pseudothoracocotyla ovalis, demonstrated little similarity between areas of northern Australia, indicating minimal short-term exchange between neighbouring groups of S. commerson. Analyses of five 'permanent' parasite species, the larval helminths G. branchi, O. cysticum, Pterobothrium sp., Callitetrarhynchus gracilis and Paranybelinia balli, also revealed large differences between areas thus indicating long-term separation. There are at least six parasitological stocks across northern Australia: Fog Bay/Bathurst Island, Cape Wessel. Groote/Sir Edward Pellew. Mornington Island, Weipa. and the Torres Strait. The occurrence of a few irregular fish in the samples suggested that LIP to 5% of fish moved between stocks during their lifetime. The similarity of within-school variability to that between schools showed that the fish do not form long-term school associations. (C) 2003 The Fisheries Society of the British Isles.
Resumo:
Upper Devonian to Lower Carboniferous strata of the Campwyn Volcanics of east central Queensland preserve a substantial sequence of first-cycle volcaniclastic sedimentary and coeval volcanic rocks that record prolonged volcanic activity along the northern New England Fold Belt. The style and scale of volcanism varied with time, producing an Upper Devonian sequence of mafic volcano-sedimentary rocks overlain by a rhyolitic ignimbrite-dominated sequence that passes upward into a Lower Carboniferous limestone-bearing sedimentary sequence. We define two facies associations for the Campwyn Volcanics. A lower facies association is dominated by mafic volcanic-derived sedimentary breccias with subordinate primary mafic volcanic rocks comprising predominantly hyaloclastite and peperite. Sedimentary breccias record episodic and high energy, subaqueous depositional events with clastic material sourced from a mafic lava-dominated terrain. Some breccias contain a high proportion of attenuated dense, glassy mafic juvenile clasts, suggesting a syn-eruptive origin. The lower facies association coarsens upwards from a lithic sand-dominated sequence through a thick interval of pebble- to boulder-grade polymict volcaniclastic breccias, culminating in facies that demonstrate subaerial exposure. The silicic upper facies association marks a significant change in eruptive style, magma composition and the nature of eruptive sources, as well as the widespread development of subaerial depositional conditions. Crystal-rich, high-grade, low- to high-silica rhyolite ignimbrites dominate the base of this facies association. Biostratigraphic age controls indicate that the ignimbrite-bearing sequences are Famennian to lower-mid Tournaisian in age. The ignimbrites represent extra-caldera facies with individual units up to 40 m thick and mostly lacking coarse lithic breccias. Thick deposits of pyroclastic material interbedded with fine-grained siliceous sandstone and mudstone (locally radiolarian-bearing) were deposited from pyroclastic flows that crossed palaeoshorelines or represent syn-eruptive, resedimented pyroclastic material. Some block-bearing lithic-pumice-crystal breccias may also reflect more proximal subaqueous silicic explosive eruptions. Crystal-lithic sandstones interbedded with, and overlying the ignimbrites, contain abundant detrital volcanic quartz and feldspar derived from the pyroclastic deposits. Limestone is common in the upper part of the upper facies association, and several beds are oolitic (cf. Rockhampton Group of the Yarrol terrane). Overall, the upper facies association fines upward and is transgressive, recording a return to shallow-marine conditions. Palaeocurrent data from all stratigraphic levels in the Campwyn Volcanics indicate that the regional sediment-dispersal direction was to the northwest, and opposed to the generally accepted notion of easterly sediment dispersal from a volcanic arc source. The silicic upper facies association correlates in age and lithology to Early Carboniferous silicic volcanism in the Drummond (Cycle 1) and Burdekin Basins, Connors Arch, and in the Yarrol terranes of eastern Queensland. The widespread development of silicic volcanism in the Early Carboniferous indicates that silicic (rift-related) magmatism was not restricted to the Drummond Basin, but was part of a more substantial silicic igneous province.