72 research outputs found
Detrimental synergy; Deciphering the roles of Aquaporins in Parkinson’s Disease
No full textParkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive selective loss of dopaminergic neurons (DN) in substantia nigra pars compacta (SNpc). The etiology of PD is unknown, though environmental toxins and neuroinflammation are identified as potential key factors in the pathogenesis. The protein channels aquaporin 4 (AQP4) and aquaporin 9 (AQP9) are expressed in a variety of brain regions, including the SN, where AQP9 is found expressed in the DN. AQP4 is selectively permeable to water and has been coupled to several neurodegenerative diseases, where neuroinflammation is a common denominator. AQP9 is on the contrary permeable to a broad spectrum of solutes.
The aim of this thesis was to evaluate the potential pathophysiological roles of AQP4 and AQP9 in PD by focusing on glial aspects of neuroinflammation and toxic contribution. Using two different mouse models of PD, through subcutaneous and intrastriatal injections of the parkinsonogenic toxin MPTP/MPP+, we show that AQP4 is highly expressed in SNpc under physiological conditions and further increased in the PD mouse models. We show that treatment with MPP+ lead to upregulation of genes known to activate microglia in SNpc in WT mice and not in Aqp4-/- mice. WT mice showed higher degree of dopaminergic cell death. To investigate the theory that AQP9 functions as a gateway channel for parkinsonogenic toxins, we established AQP9 permeability to MPP+ by using Xenopus oocytes expressing AQP9. Targeted deletion of Aqp9 proved protective of dopaminergic cell death both in vitro and in vivo in the MPP+ mouse model.
In conclusion, this thesis has pinpointed AQP4 and AQP9 as detrimental factors in the pathogenesis of PD, where AQP9 functions as a toxin facilitator enabling access to DN whereas AQP4 plays the role of toxin exacerbator, amplifying the toxic effect in SNpc through neuroinflammation. This novel insight in to the pathogenesis of PD, may pave the way for new therapeutic targets in PD
Prydz Bay Current Meter Data 1984-1985
No full textProgress Code: completedStatement: Six current meters of the eleven deployed were recovered with data intact. Mooring 2 was not recovered. Meter 7621 failed due to a fault in the tape drive. Data were read from Aanderaa tapes and processed to produce a calibrated data file. Further processing consisted of tidal height and spectral analyses. Calibrated files contain 5 lines of header information followed by the data in 14-column format. Scatter plots of U and V velocity, progressive-vector plots, temperature/time plots, stick plots, tidal current analyses, residual time series and power spectra have been produced from the data, and are presented in the report referenced above.This dataset contains current meter data from Prydz Bay, Antarctica. Current meters were deployed on 3 moorings around Prydz Bay between January 1984 and February 1985. Summary results and deployment details are in the documentation. Temperature and salinity were also recorded. Records are not continuous at each site over this time period. Each mooring contains three or four current meters, measuring water temperature, speed and direction, and for some meters conductivity. Moorings 1 and 2 consisted of four Aanderaa current meters with target meter deployment depths of 200m, 350m, 500 m and near bottom. Mooring 3 had three Aanderaa current meters, with depths of 200m, 350m and near bottom.<br/><br/>The fields in this dataset are:<br/>DEVICE IDENTIFICATION<br/>SAMPLE PERIOD<br/>TEMPERATURE PARAMETERS<br/>CONDUCTIVITY PARAMETERS<br/>SEA CURRENT DIRECTION PARAMETERS<br/>SEA CURRENT SPEED PARAMETERS<br/>DATE<br/>TIME<br/>TEMPERATURE (DEGREES C)<br/>SALINITY (Ppt)<br/>DIRECTION (degrees)<br/>SPEED (knots
Community composition of seabirds in the Prydz Bay region, derived from at-sea observations of seabirds.
No full textProgress Code: completedObservations of seabirds at sea have been made by observers on Australian Antarctic ships in the Prydz Bay region during most seasons since 1980/81. Approximately 32000 observations of 26 main species were made from the 1980/81 to 2001/02 seasons. These observations provide a two-decade history of seabird activity in this region of the Antarctic. This project used clustering techniques to identify the communities within the seabird populations.<br/><br/>Summary of results<br/><br/>We found three distinct communities of seabirds within Prydz Bay. The first comprised all nine species of seabird which breed in the Prydz Bay area (emperor and Adelie penguins, snow, Cape, and Antarctic petrels, southern giant petrels, southern fulmars, Wilson's storm petrel, and south polar skuas). The second comprised those species which breed in sub-Antarctic or temperate regions and forage in Prydz Bay in the summer months (including many species of albatrosses and shearwaters). There was an overlap of these two communities which had a broad mix of species.<br/><br/>The spatial and temporal ranges of these communities is given in this data set.<br/><br/>The raw data for this dataset was generated through ASAC project 2208 - Distribution and abundance of seabirds in the Southern Indian Ocean, 1980/81+ (ASAC_2208_seabirds).<br/><br/>The fields in this dataset are:<br/><br/>Year<br/>Month<br/>Day<br/>Hour<br/>Minute<br/>Voyage<br/>Latitude<br/>Longitude<br/>Assemblage<br/>Constancy<br/>Fidelit
Prydz Bay Current Meter Data 1987-1988
No full textProgress Code: completedStatement: Only two of the moorings were recovered, mooring 2 and 5, one from both the summer and winter deployment programs. Six of the twelve current meters were recovered. Data were read from Aanderaa tapes and the S4 solid state memory and processed to produce a calibrated data file. Scatter, vector-sum, temperature/time and vector/time (stick) plots were produced. Time series of all data columns from the current meters have been produced, and for the S4 time series of the standard deviation of the U (east) and V (north) velocities. Tidal current analyses have been performed for the currents from each meter.This dataset contains current meter data from Prydz Bay, Antarctica. Current meters were deployed on 5 moorings around Prydz Bay between March 1987 and February 1988. Summary results and deployment details are in the documentation. Temperature and salinity were also recorded. Records are not continuous at each site over this time period. Mooring 1 had a single current meter with a target depth of 100-200m, mooring 2 had 2 Aanderaa current meters with deployment depths of 223m and 425m and an S4 current vector-averaging meter at 123m from the surface, mooring 3 had 2 Aanderaa current meters at target depths of 300m and 1500m, Mooring 4 had 4 Aanderaa current meters with depths of 182m, 328m, 430m and 512m, mooring 5 had 4 Aanderaa meters at 273m, 419m, 567m and 670m. Three moorings were deployed for a full year, March 1987 to February 1988 (the 'winter' deployment) and 2 moorings released in October 1987 for about 4 months ('summer' deployment). Six of the 12 current meters deployed were recovered.<br/><br/>The fields in this dataset are:<br/>DEVICE IDENTIFICATION<br/>SAMPLE PERIOD<br/>TEMPERATURE PARAMETERS<br/>CONDUCTIVITY PARAMETERS<br/>SEA CURRENT DIRECTION PARAMETERS<br/>SEA CURRENT SPEED PARAMETERS<br/>DATE<br/>TIME<br/>TEMPERATURE (DEGREES C)<br/>SALINITY (Ppt)<br/>DIRECTION (degrees)<br/>SPEED (knots
Recent diatom and foraminiferal assemblages in surficial sediments of Prydz Bay, Antarctica.
No full textProgress Code: completedStatement: See the ANARE Research Note for further information.Surficial bottom sediments collected from Prydz Bay, Antarctica contain three sedimentary facies, four foraminiferal faunas, and two diatom floras. A sandy diamict (Facies Ds) is deposited by iceberg rafting and reworked by currents of the Prydz Bay Cyclonic Gyre. A massive mud (Facies Mm) represents the sediments being supplied to the Bay and could provide a high resolution record of the Quaternary in Antarctica. A carbonate sand (Facies Cs) is a modern cold water carbonate deposited under special conditions on the outer continental shelf.<br/><br/>The presence of planktonic flora and fauna, and variations in sedimentological parameters are consistent with the physical oceanographic evidence for a large cyclonic gyre operating in the Bay.<br/><br/>The fields in this dataset are:<br/>Sight Device Comments<br/>Depth (m)<br/>Sample<br/>Foram<br/>Diatom<br/>Percentages of Individual species<br/>Number of individuals counted.<br/>Plankto
Prydz Bay Current Meter Data 1985-1986
No full textProgress Code: completedStatement: Only eleven of the sixteen meters were recovered with data intact. Mooring 2 was unable to be retrieved. Current meter 7621 flooded, and all data were lost. Pressure sensors on current meters 6149 and 6150 were deployed too deep and didn't record any valid pressure data. In terms of coverage, the four moorings were located so as to provide good coverage of the area. Each of the four moorings consisted of four Aanderaa current meters, at depths of 200m, 350m, 500m, and near-bottom. Eleven meters were recovered with data intact, recording time, direction, speed and temperature at 60 minute intervals. Mooring 4 had a pressure and conductivity sensor on all meters, moorings 1 and 3 had pressure sensors on current meters 7621 and 7623. Data were read from Aanderaa tapes and processed to produce a calibrated data file. Further processing consisted of tidal height and spectral analyses. Calibrated files contain 5 lines of header information followed by the data in 14-column format. Scatter plots of U and V velocity, progressive-vector plots, temperature/time plots, stick plots, tidal height analyses, power spectra and monthly tables of general statistics have been produced from the data, and are presented in the report referenced above. Analyses were performed on raw data. Power spectra were smoothed by band averaging four adjacent spectral estimates, giving each spectral estimate eight degrees of freedom. A linear detrend was applied to the time series before spectral analysis.This dataset contains current meter data from Prydz Bay, Antarctica. Four moorings each consisting of four current meters were deployed at various locations in Prydz Bay. Data was obtained between January 1985 and February 1986. Each of the four current meters per mooring measured time, water temperature, speed and direction every sixty minutes. Moorings 1 and 3 also each had one current meter equipped with a pressure sensor. All meters on mooring 4 measured pressure and conductivity. The four meters on each mooring were positioned at the intended depths of 200m, 350m, 500m and near-bottom. Eleven of the sixteen current meters deployed were recovered with data intact, and summary results and deployment details are given in the documentation.<br/><br/>The fields in this dataset are:<br/>DEVICE IDENTIFICATION<br/>SAMPLE PERIOD<br/>TEMPERATURE PARAMETERS<br/>CONDUCTIVITY PARAMETERS<br/>SEA CURRENT DIRECTION PARAMETERS<br/>SEA CURRENT SPEED PARAMETERS<br/>DATE<br/>TIME<br/>TEMPERATURE (DEGREES C)<br/>SALINITY (Ppt)<br/>DIRECTION (degrees)<br/>SPEED (knots
Parmales in sediments of Prydz Bay, East Antarctica: a new biofacies and paleoenvironmental indicator of cold water deposition?
No full textSiliceous wall plates of two species of Parmales are present in varying abundance in the surficial and downcore sediments of Prydz Bay. These organisms have a dramatically higher abundance and greater species diversity in polar and sub-polarenvironments than is seen in temperate and tropical waters. Based on the finding of abundant and well-preserved walls of these organisms in Antarctic sediments, it is suggest that they represent a useful biofacies and paleoenvironmental marker for deposition from cold water, and a potentially new biostratigraphic tool. -Author
Petrology and geochronology of granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and implications for the evolution of the Prydz Belt
No full textA combined petrological and geochronological study was carried out on mafic granulites and associated felsic gneisses from the McKaskle Hills, eastern Amery Ice Shelf, East Antarctica. Garnet-bearing mafic granulites exhibit reaction textures and exsolution textures that indicate two-stage metamorphic evolution. Thermobarometric estimates from matrix and symplectite assemblages yield peak and retrograde P-T conditions of 9.0-9.5 kbar and 880-950°C and 6.6-7.2 kbar and 700-750°C, respectively. Similar but slightly scattered peak P-T estimates of 7.9-10.1 kbar and 820-980°C are obtained from the core compositions of minerals from felsic para- and orthogneisses. Evidence for the prograde history is provided by muscovite inclusions in garnet from a paragneiss. Sensitive high-resolution ion microprobe U-Pb zircon dating reveals an evolutionary history for the granulites, including a mafic and felsic igneous intrusion at 1174-1019 Ma, sedimentation after 932-916 Ma, and a high-grade metamorphism at 533-529 Ma. In contrast, Sm-Nd mineral-whole-rock dating mainly yields a single age population at ∼500 Ma. This suggests that the McKaskle Hills form part of the Prydz Belt, and that the relatively high peak P-T conditions and a decompression-dominated P-T path for the rocks resulted from a single Cambrian metamorphic cycle, rather than two distinct metamorphic events as formerly inferred for the granulites from Prydz Bay. The age data also indicate that the Precambrian history of the McKaskle Hills is not only distinct from that of the early Neoproterozoic terrane in the northern Prince Charles Mountains, but also different from that of other parts of the Prydz Belt. The existence of multiple basement terranes, together with considerable crustal thickening followed by tectonic uplift and unroofing indicated by the clockwise P-T-t evolution, suggests that the Prydz Belt may represent a collisional orogen that resulted in the assembly of Gondwana during the Cambrian period. © The Author 2007. Published by Oxford University Press. All rights reserved.link_to_subscribed_fulltex
Foraminiferida in the Mac. Robertson Shelf–Prydz Bay region, East Antarctica: distribution and controls - unfinished study
No full textStatement: These data were discovered on AADC servers, and are possibly unfinished/unchecked. Quality of the dataset cannot be guaranteed.These data are linked to what appears to be an unfinished report/paper by Pat Quilty. An extract of the unfinished report is available below, and the full document is included in the data download.<br/><br/>These data are also linked to a collection in the biodiversity database, and are also related to another record (both listed at the provided URLs).<br/><br/>Foraminiferids are recorded from samples collected on Mac. Robertson Shelf and Prydz Bay, East Antarctica in 1982, 1995 and 1997. Most are identifiable from previous literature but a new enrolled biserial agglutinated genus is noted but not defined. Distribution is related to oceanographic factors.<br/><br/>The Mac. Robertson Shelf-Prydz Bay region off the East Antarctic coast is that segment of the southern Indian Ocean between latitudes 66 degrees and almost 70 degrees S, and longitudes 60 degrees and 80 degrees E. It includes Mac. Robertson Shelf, the continental shelf, bounded seaward by the 500 m isobath, and Prydz Bay, the deepest re-entrant into the east Antarctic shield and the outlet for the Lambert Glacier at its southern end. The Lambert Glacier is the world’s largest glacier and drains some 1 000 000 km2 of East Antarctica. The marine region studied here covers some 140 000 km2.<br/><br/>Several research cruises to the region have collected sediment samples that yielded modern and recycled foraminiferid faunas. The modern component of the faunas has not been recorded in detail previously. <br/><br/>This paper records the details of the taxonomy and distribution of species collected during marine geology/geophysics cruises that provided the foraminiferids discussed in Quilty (1985, 2001), O’Brien (1992), O’Brien et al. (1993, 1995) and Harris et al. (1997). The geophysical results and interpretations of the 1982 voyage of MV Nella Dan are described by Stagg (1985) and this provides also the general setting and nomenclature of Prydz Bay. Two cruises (1995 and 1997) of RSV Aurora Australis collected samples and these provided the basis for Quilty’s records of foraminiferids and other components on a sample-by-sample basis in O’Brien et al. (1995) from 51 samples, and from a further 27 samples reported in Harris et al. (1997). The 1995 cruise also yielded the recycled foraminifera recorded by Quilty (2001) and the Mesozoic material documented by Truswell et al. (1999). Neither of these cruise records provided details of the faunas to the level covered here. Further studies for the region are given in the results of ODP Legs 119 and 188.<br/><br/>The impetus for conducting this review comes from two sources. Firstly, few foraminiferids have been documented from this region, and even fewer have been figured. Secondly, 2007-2008 was designated the [fourth] International Polar Year (IPY) and one of the major programs is the Census of Antarctic Marine Life (CAML), a component of the global Census of Marine Life (CML). This paper is a contribution to that project. Included in the review are faunas from the modern environment and some which may be ‘Late Cenozoic’ in which the faunas are of the same species as the modern and in which data from the modern can be, and have been, used to infer past environments (Fillon 1974, Kellogg et al. 1979, Ward and Webb 1986).<br/> <br/>The aims of this paper are: <br/>- to document the species of foraminifera recovered from geology/geophysics cruises to the Mac. Robertson Shelf and Prydz Bay region, offshore East Antarctica (Fig. 1);<br/>- to make the nomenclature of species recorded consistent with latest taxonomic practice; <br/>- to characterise the faunas by diversity and dominance factors; and<br/>- to discuss the controls on the distribution of faunas recorded
The Prydz Bay Adelie Penguin/Prey Stock Interaction, a Monitoring Program
No full textProgress Code: completedStatement:
Dates provided in temporal coverage are approximate only.Metadata record for data from ASAC Project 106<br/>See the link below for public details on this project.<br/><br/>From the abstracts of some of the referenced papers:<br/><br/>This paper reports the results of the first aerial photographic survey of Adelie penguin colonies in the Prydz Bay region. The area surveyed extended from the northern Vestfold Hills to the Publications Ice Shelf. More than 325,000 pairs of Adelie penguins were estimated to be breeding in this region in 1981/82. The great majority of breeding Adelie penguins occurred in the northern half of the region surveyed, in the Vestfold hills and Rauer Islands, where most colonies were located. This is probably due to the typical pattern of summer sea-ice dispersal, which usually results in sea-ice leaving the northern areas of the coast first. <br/><br/>Prydz Bay supports nine seabird species that breed on the Princess Elizabeth Land coast: two penguins, six Procellariiformes and one skua. Information on their diet is reviewed. Apart from the scavenging South Polar Skua Catharacta maccormicki and Southern Giant Petrel Macronectes giganteus, three diet types were distinguished. First, the Emperor Penguin Aptenodytes forsteri ate almost exclusively fish; secondly the Adelie Penguin Pygoscelis adeliae, Cape Petrel Daption capense, and Wilson's Storm Petrel Oceanites oceanicus consumed at least 60% euphausiid, the remainder largely fish; and thirdly, a diet of greater than 60% fish, the rest euphausiids, was taken by the Southern Fulmar Fulmarus glacialoides, Antarctic Petrel Thalassoica antarctica and Snow Petrel Pagodroma nivea. Seasonal fluctuation in composition of Adelie Penguin, Cape Petrel and Southern Fulmar diet suggested either fluctuating foraging ranges or movement of Euphausia superba inshore during summer months. Annual fluctuation in diet composition was correlated with seabird reproductive success. When E. crystallorophias dominated the euphausiid component of Adelie Penguin diet, reproductive success was high; when E. superba was scarce in Prydz Bay, Antarctic Petrel and Southern Fulmar productivity was low.<br/><br/>Breeding phenology, success and nest attendance of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides at the Rauer Group, East Antarctica, are discussed. Most data were collected on Hop Island in January and February 1988, and from December 1988 to March 1989. Observations extended from the late stages of incubation to post-guard or fledging periods. Some annual breeding indices collected from 1983 onwards at census sites are compared with meteorological data and the extent of fast ice for the nearby Davis Station. Both species had a restricted hatching period, reflecting a brief and synchronised egg-laying period, reflecting a brief and synchronised egg-laying period, typical of other southern fulmarine petrels. Antarctic Petrel chicks hatched from 4 January (1989) and c. 90% appeared by 16 January (both years). Southern Fulmar hatching began on 21 January (1988) and almost all chicks appeared by 6 February (both years). Adult attendance at nests declined with increasing chick age. For Antarctic Petrels, this was most marked at about 11 days; no chicks had continuously attendant adults after 24 days, although adults returned to feed them. Incubation shifts following hatching and the post-guard period started, on average, 13 days after hatching. Egg and chick losses varied between years and sites. The South Polar Skua Catharacta maccormicki was apparently involved in the majority of losses. Nest sites of both species resemble those elsewhere: Southern Fulmars may require steeper sites, allowing a fall away from colonies. Antarctic Petrels are less affected by accumulation of snow or ice and shelter from katabatic winds may be important. Although weather may modify breeding success locally, annual success must depend on the ability of parents to produce eggs and feed chicks: this may be moderated by the extent and persistence of pack ice.<br/><br/>Annual chick productivity and breeding success, recorded at four Adelie penguin, Pygoscelis adeliae, colonies at Magnetic Island in eastern Prydz Bay, are presented for the seven breeding seasons 1981/82 to 1987/88. The adult breeding population remained relatively stable during the first 4 years of the study, and increased in hte last 2 years. Substantial annual variation in breeding success occurred over the study period, ranging between an estimated 0.69 and 1.33 chicks surviving until late creche stage per nest for seasons 1985/86 and 1982/83 respectively. Annual patterns of chick productivity in southern fulmar, Fulmarus glacialoides, and Antarctic petrel, Thalassoica antarctica, populations within Prydz Bay were synchronous with those of Adelie penguins. In the years of highest and lowest reproductive performance, prey abundance within the likely foraging areas was correspondingly high and low. Reproductive performance was greatest in years when fast-ice breakout occurred before the end of December (1981/82, 1982/83. 1986/87 and 1987/88) and lowest when the breakout was after (1983/84, 1984/85 and 1985/86) and pack-ice cover persisted within the foraging range of the birds during the chick-rearing period
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