Journal and Proceedings of
The Royal Society of New South Wales
Volume 137 Parts 1 and 2
Cult and Archaeology at Pella in Jordan: Excavating the Bronze and Iron Age Temple Precinct (1994-2001)
Stephen J. Bourke
Abstract: This article summarises key discoveries of the University of Sydney excavations at Pella in Jordan between 1996-2001. Work centred on the excavation of a three-phase fortress temple complex on the south side of the city mound, and in the study of changing cult practice in the temple precinct over the 800 years of its occupation (ca 1600-800 BC). A detailed analysis of changing architectural form and cult practice is presented, and appropriate regional parallels both cultic and cultural outlined.
Keywords
archaeology, near east, Jordan, Bronze Age, religion, temple, cult practice
2021
Presidential Address 2002
Karina Kelly
Abstract: The Royal Society of New South Wales was first founded in 1821 as the Philosophical Society of Australasia. At that time New South Wales encompassed the states of Queensland, NSW, Victoria and Tasmania as well as New Zealand. The Society has had a rich and interesting history and is the oldest scientific society in Australia. Founded by interested amateurs, the Society has had some interesting and influential members over the last one hundred and eighty three years. This paper documents some of the history of the Society and also speculates on where science of the present day and the Royal Society of New South Wales may be headed in the future.
Keywords
Royal Society of New South Wales, NSW History, Science History, Australian Science
Thesis Abstracts
Baird, Andrew H.
Brodie, Gilianne D.
Costelloe, Marina Therese
Cox, Murray P.
Crosby, Kirsten
Dai, Quan
Eyles, Rebekah Faye
Glatz, Richard V.
Holdsworth, David K
Lautensach, Alexander K.
Le, Hoi Christian Manuel,
Lichon, Michael J.
Milosavljevic, Stephan
Segan, Cathy J.
Walsh, Peter
Westphal, Thorsk G.
Woolley, Adele Glyn
Thesis Abstract: The Ecology of Coral Larvae: Settlement Patterns, Habitat Selection and the Length of the Larval Phase
Andrew H. Baird
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy, James Cook University, Townsville, Queensland 2001
Underestimating the capacity of larvae to influence their fate has been a recurrent theme of marine ecology. Consequently, ecologists have focused on post-settlement processes to explain the distribution and abundance of benthic marine organisms. Coral larvae, in particular, are typically viewed as simple organisms with little capacity to control their position in the water column or sense their environment. In this thesis, I demonstrate that coral larval ecology can have a profound affect on adult distributions. Firstly, I examined the depth patterns of coral settlement over a two-year period at four locations around Lizard Island on the Great Barrier Reef. Many taxa showed a pronounced and consistent decline with depth. In particular, settlement of Isopora and Pocillopora was largely restricted to the reef crest. A similar pattern was evident in the adults of these taxa, suggesting that larvae can recognize and respond to cues from the parental habitat. To test this hypothesis the larvae of six common coral species, with contrasting depth distributions, were introduced into aquaria containing tiles conditioned at a depth of 2m, 12m and unconditioned tiles. Larval substratum preferences generally corresponded with those predicted on the basis of the depth distribution of the adults. Zone-specific species showed a clear and pronounced preference for tiles conditioned in the parental habitat. For example, Goniastrea aspera a reef-flat species, settled on shallow tiles in densities 4 times greater than on deep tiles. Similarly, Fungia horrida, a species locally restricted to deeper water, was 6 times more abundant on deep tiles. These results confirm that the depth distribution of these species is influenced, in part, by patterns established at settlement. Another area where coral larval ecology has been neglected is in investigating the scale of dispersal. To test the likelihood of localised recruitment and the potential of coral larvae for long distance dispersal, I compared the frequency distribution of settlement and the longevity of larvae in four Acropora and two faviid corals. Some settlement was record within 4d of gamete release in all species, indicating a shorter pre-competent period in these species than has been generally accepted. Competence peaked at over 50% of the surviving cohort within 7-10d after which the proportion competent to settle dropped rapidly in all species except A. valida and A. millepora, where 50% of the surviving cohort remained competent for over 30d. Maximum competence periods were 110d for A. valida, 60d for A. millepora, 36d for G. retiformis, 34d for A. gemmifera and P. daedalea. These competence periods should produce sufficient gene flow to prevent populations diverging over a wide geographical area. However, larval survivorship was low in all species with less than 50% of larvae alive after 14d and less than 10% alive after 30d. Low survivorship combined with a rapid drop in the proportion of larvae competent to settle after two weeks suggests that numbers of migrants are unlikely to be sufficient to sustain population abundance on distant reefs.
Dr Andrew H. Baird
Centre for Coral Reef Biodiversity
School of Marine Biology and Aquaculture
James Cook University
Townsville Queensland 4811
Australia.
Thesis Abstract: The Molluscan Nudibranch Family Dendrodorididae (Anthobranchia: Doridoidea) in Australia: Systematics and Phylogenetic Relationships
Gilianne D. Brodie
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy
James Cook University, Townsville, Queensland 2004
The Doridoidea is a very diverse superfamily of marine molluscs, which includes all "dorid" nudibranchs (Gastropoda: Opisthobranchia: Nudibranchia), except the Antarctic Bathydorididae. Three of an estimated twenty-five doridoidean families, including the family Dendrodorididae, are unusual because its members lack the characteristic molluscan radula or feeding organ. This makes these families very intriguing in an evolutionary sense.
Historically the family Dendrodorididae consists of two genera, Dendrodoris and Doriopsilla. The putative Australian members of these two genera, many of which have an Indo-west Pacific distribution, have never been systematically examined or reviewed before the current study. This has made both taxonomic and phylogenetic analysis of the family at a broader level difficult. The first aim of this project was to undertake a taxonomic investigation of members of the family Dendrodorididae in Australia, placing considerable emphasis on internal dissection, microstructural analysis and the examination of type material. This task has never been attempted before, with the relevant literature being scattered throughout publications spanning the last 170 years. In spite of the relative rarity of several of the species studied I was able to collate informative taxonomic data for all of the sixteen previously recorded Australian species.
Twelve species of Dendrodoris and four species of Doriopsilla were confirmed as valid and occurring in Australian waters. Dendrodoris was found to possess well-defined generic features, while each species possessed distinctive characteristics. On the other hand, although Doriopsilla was found to possess several worthy generic features, well-defined species characteristics were lacking, making species identification fraught with difficulty.
The little-known temperate species Dendrodoris maugeana was found to be unique within the dendrodorids examined, possessing a reproductive system quite different from other members of the family. The relatively common species Dendrodoris nigra was also found to be unusual, possessing symbiotic bacteria in its reproductive system; a phenomenon previously unrecognised within any gastropod mollusc. Another new feature found by the present study in several Dendrodoris species was the presence of a very distinct muscular sphincter within the walls of the anal papilla just prior to the anus.
Dendrodoris and Doriopsilla were found to be anatomically different, particularly in the arrangement of the anterior part of the digestive system. Members of Dendrodoris were clearly united by the possession of a ptyaline gland and a uniquely glandular oesophagus while previously undescribed complex notal glands and an anal papilla located to the left of the gill branchia united Doriopsilla. Except for general plesiomorphic features of doridoidean nudibranchs (e.g., dorso-posterior gill position) and adaptations related to feeding method (i.e. a ventral mouth and highly modified digestive system), features that unite these two genera together into a family were lacking.
Another aim of this project was to investigate phylogenetic relationships both within the family Dendrodorididae and between Dendrodorididae and other radula-less Doridoidea. Debate has existed as to whether radular loss has occurred more than once in the doridoidean nudibranchs and thus whether or not radula-less taxa should be grouped together as the infraorder Porostomata. Previous phylogenetic studies involving these groups have given conflicting results, therefore emphasising a need for new character sets.
Thirteen dendrodorids were investigated in detail for the phylogenetic study (10 Dendrodoris and 3 Doriopsilla species) using traditional morphological methods and histological techniques. The histological techniques were used to compare organ microstructure, particularly of glandular tissues. Representative members of the other radula-less doridoidean families (Mandeliidae and Phyllidiidae) and of radula-bearing Doridoidea (including both phanerobranch and cryptobranch taxa) were also investigated as outgroups. The cladistic analyses supported the monophyly of the radula-less Doridoidea (= Porostomata) and therefore a single occurrence of radular loss. However, the family Dendrodorididae (Dendrodoris + Doriopsilla) was found to be polyphyletic and there is little support for its retention as presently constituted.
Three alternatives for a new classification are presented, with the favoured option being an increase in the number of porostome families from three (Phyllidiidae, Mandeliidae, Dendrodorididae) to four, i.e., Phyllidiidae, Mandeliidae, Dendrodorididae (containing only Dendrodoris) and a new family (containing only Doriopsilla). The revised taxa are redescribed based on anatomical features discovered by this analysis.
Vestibular glands in the reproductive system, and notal gland microanatomy in particular, were found to be of considerable phylogenetic value. The present study highlighted the need for histological investigation of such glands, since their positioning within the body wall or connective tissue can cause presence to be overlooked by dissection alone. In light of these results, previously described species will require reinvestigation by histological means before a genuine absence of such characters can be confirmed. The unexpected discovery of mantle dermal formations (MDFs) in the monospecific family Mandeliidae clearly supports its separation from other radula-less taxa. It also highlights the need for a broader study of relationships within Doridoidea, as these highly specialised notal glands have previously been found only in the radula-bearing doridoidean families Chromodorididae and Triophidae.
The current study has provided a substantial amount of new structural information about Dendrodoris and Doriopsilla. A broader investigation of the Doridoidea (a very diverse taxon) is now required to determine more precisely the relationship of these two families, and the Porostomata, to other doridoidean taxa.
Dr Gilianne D. Brodie
School of Marine Biology and Aquaculture
James Cook University
Townsvill, Queensland 4811
email: gilianne dot brodie AT jcu dot edu dot au
Thesis Abstract: Environmental Review of the Mary Kathleen Uranium Mine
Marina Therese Costelloe
Abstract of a Thesis submitted for the Degree of Master of Science James Cook University, Townsville, Queensland 2003
The major aim of this project has been to investigate the current environmental status of the historic Mary Kathleen mine site including the open pit; D Stockpile, Crusher, Goldings West, West Tip, Southern Tip and North Waste Tip pile; evaporation ponds and tailings dams; tailings dam seepage and Cameron Creek. This study will provide data for an integrated assessment of the site and comparison to current ANZECC water, soil and stream sediment guidelines.
In the Mary Kathleen open pit, skarn type U-Th-REE mineralisation is hosted in amphibolite grade metamorphosed calc-silicate, mafic to intermediate igneous and sedimentary rocks. Elevated gamma-ray readings in the open pit correspond to exposed ore lenses (26 mSv/year) and the abandoned ore stockpile (10.7 mSv/year). Surficial oxidation of ore and adjacent sulphide-bearing calc-silicate rocks has led to contemporary precipitation of mineral efflorescences on the pit walls. The open pit lake contains saline (0.15%) surface waters which are Ca2+, SO4- rich with elevated Cu (1170 µg/L), Fe (3230 µg/L), Mn (1050 µg/L), Ni (688 µg/L) and U (460 µg/L) at a pH of 6.11.
Waste rock piles are up to 30m thick and several, which were only partly covered or ripped for seeding, have high radiation levels (25 mSv/year). Stream sediments accumulating below waste rock piles are acidic (pH 3.8-7) and results (mean values) show enrichment of Cu (323 ppm), Mn (945 ppm), Ni (90 ppm), Ce (806 ppm), La (531 ppm) and U (82 ppm) indicating active weathering and erosion of waste materials into the local drainage system. Biogeochemical analyses indicate that Enneapogon lindleyanus (grass), Cymbopogon bombycinus (grass), Aerva javanica (kapok bush), Aristida longicollis (poaceae) and Acacia Chisholmii (wattle) accumulate Cu, Mn, Ni, REE and U at mined and disturbed areas.
Gamma-ray measurements over the rehabilitated tailings dam demonstrate an intact cover. However, seepage of acid (pH 5.86), saline (0.31%) waters occurs from the toe of the tailings dam into the evaporation ponds and local drainage system. Seepage waters are Ca2+, SO4- rich with elevated Fe (250 mg/L), Mn (328 mg/L), and U (303 µg/L). Abundant sulphate efflorescences and Fe-oxyhydroxide flocculants with elevated radiation (1300 cps), high REE (Ce 6840 ppm, La 3750 ppm) and U (901 ppm) levels precipitate at the seepage point. Thus radionuclides are mobilised into surface seepage waters, and are coprecipitated with Fe flocculants. Runoff from the mine area drains into Cameron Creek. Seepage of saline waters occurs from the tailings dam and evaporation ponds into Cameron Creek via surface and subsurface flows as indicated by salt-encrusted creek banks.
When sampled during the dry season, pools in the Cameron Creek system were shallow, saline (0.3-3%), alkaline (pH 8.3-8.6), and strongly enriched in SO4 (25.8 mg/L) and U (5.1 mg/L) but fish and aquatic plant life were still sustained locally in lower salinity regimes. Elevated metal loadings of soils and sediments, radionuclide mobility, weathering and erosion of waste dumps and bioaccumulation of elements do not occur beyond the former mine site. Measured radiation levels are at or below Australian Radiation Protection Standards (20 mSv/year averaged over five consecutive years) in most areas. In contrast, seepage of waters from the tailings storage area and evaporation ponds causes seasonal salinisation and impacts on the water quality of Cameron Creek during the dry season.
Acknowledgements
To Dr Bernd Lottermoser and Dr Paul Ashley for their tremendous contribution to the research project. Support for this project was given by the Australian Research Council, James Cook University and the Queensland Department of Mines and Energy. David Trezise (DME Qld) and Geoff Bradford (EPA Qld) are thanked for their assistance and support. Vegetation sample identifications were made by N.J. Beresford-Smith and the Queensland Herbarium.
Marina Therese Costelloe
7 Wirria Circuit
Ngunnawal ACT 2913
email: marinac AT bigpond dot com
Thesis Abstract: Genetic Patterning at Austronesian Contact Zones
Murray P. Cox
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand 2003
The advance of Neolithic culture was a defining process in human history. Chronicled by the distribution of Austronesian languages, one such expansion of Neolithic peoples swept through the Indo-Pacific region just 4,000 years ago. A record of this dispersal is carried in the genes of modern people. Yet human populations have a much older history in the region, and their genetic legacies also persist to modern times. Examination of the genetic patterns that resulted from contact between these Austronesian and non-Austronesian peoples forms a central focus of this thesis. Research was directed towards three geographical regions in which Austronesian languages are still spoken today: the island nations of Indonesia, Madagascar, and Vanuatu. Inherited genetic characters were examined from nearly six hundred individuals, and analysis focused on two genetic systems. Firstly, mitochondrial DNA, which is inherited through the maternal line; and secondly, the Y chromosome, which is inherited through the paternal line. Disengaging the genetic lineages of men and women allowed exploration of possible sex-specific structuring in the contact process. An examination of spatial patterning, and the application of novel genetic techniques for dating human population expansions, gave additional facets to the study. Four thousand years of human mobility have blurred prehistoric patterns in the genetic variation displayed by modern populations. No spatial or sex-specific patterning was detected. Yet it can be inferred that less than a fifth part of the modern populace carry genetic markers once diagnostic of the dispersing Austronesian speakers. It seems that non-Austronesian populations have contributed significantly to modern populations. Genetic analysis suggests that, at least in Vanuatu, adoption of a Neolithic economy triggered a period of population growth for non-Austronesian peoples. This was contemporary with the arrival of the first Austronesians. Thus, the spread of Neolithic society seems to have been driven in part by biological dispersal, and in part by cultural diffusion. The genetic data best fit a model of leapfrogging, whereby Austronesian populations crossed the Indo-Pacific region in bounds, each of which subsequently formed a staging ground for cultural diffusion. Although not reflected so clearly in the archaeological and linguistic records, non-Austronesian peoples were active players in the emerging Neolithic world. They encountered the dispersal of the Austronesians, adapted culturally to their changing situation, and biologically, they kept on going.
Dr Murray P. Cox
The Leverhulme Centre for Human Evolutionary Studies,
Department of Biological Anthropology,
University of Cambridge,
Downing Street,
Cambridge CB2 3DZ
United Kingdom
email: mpc42 AT cam dot ac dot uk
Thesis Abstract: Studies in the Diversity and Evolution of Phalangeroid Possums (Marsupialia; Phalangerida; Phalangeroidea)
Kirsten Crosby
Abstract of a Thesis awarded for the Degree of Doctor of Philosophy University of New South Wales, Australia 2003
Keywords: Phalangeroidea, Miocene, Riversleigh, possum
Three new genera (Onirocuscus, Illungalya and Caudipilosus) of phalangerids are described from the Riversleigh World Heritage fossil property, northwestern Queensland. One previously described fossil species of Trichosurus and two of Strigocuscus and rediagnosed. These are referred to the new genera Caudipilosus and Onirocuscus respectively. In all, six new species of phalangerid are described in the three genera, and three species rediagnosed. Two phalangeroids are also described, one a miralinid (in the genus Durudawiri) and one that is unassigned to family.
Phylogenetic analyses of these and other phalangerids supports the division of the family as proposed by Flannery et al. (1987a) and George (1987). Strigocuscus is found to contain only one species, the extant Strigocuscus celebensis. The three new phalangerid genera form a monophyletic clade that is sister group to modern trichosurins, and described here as a new subtribe. Periotic morphology provides a basis for distinguishing the two subtribes. Phylogenetic analysis was also performed on the suborder Phalangerida. Tarsipedidae were generally found to be the most plesiomorphic family of possum. Superfamily Petauroidea sensu Aplin and Archer 1987 gained little support. Burramyidae often formed a sister group to Phalangeroidea (including Pilkipildridae).
In the Riversleigh deposits, the highest diversity of phalangerids occurs in the early Miocene, followed by diversity in the middle Miocene. By the late Miocene, only one species of phalangerid (genus Trichosurus) is known from Riversleigh. Today, Trichosurus vulpecula arnhemensis is the only phalangerid found in northwestern Queensland.
Dr Kirsten Crosby
School of Biological, Earth and Environmental Sciences
University of New South Wales
Sydney 2052, Australia
email: k dot crosby AT unsw dot edu dot au
Thesis Abstract: Adenovirus-medited Gene Transfer for Tendon Healing
Quan Dai
Abstract of a Thesis awarded for the Degree of Master of Science
University of New South Wales, Australia 2002
The delivery of therapeutic genes to injured tendon via an adenovirus vector is an attractive potential method for enhancing tendon healing. Genes encoding proteins that are important to healing can easily be incorporated into an adenovirus expression vector; which, following transfection into a tendon cell, allows the therapeutic protein to be transiently expressed. As a first step of developing gene therapy for tendon healing, we studied the feasibility and efficacy of adenovirus-mediated gene transfer in vitro and in vivo; and explored a novel method to enhance adenovirus transfection in vivo by immobilizing the virus with a gelatin sponge.
We investigated the transfection of Ad5CMVntLacZ, an adenovirus vector containing reporter gene LacZ, in human rotator cuff tendon cell in vitro, and in a rat Achilles tendon healing model in vivo. Ad5CMVempty, the adenoviral vector containing no inserted gene, was used as a control for adenoviral transfection alone. For the in vitro work, human rotator cuff tendon cells were obtained by primary cell-culture; and transfected with Ad5CMVntLacZ. Activity of β-galactosidase, the protein product expressed by LacZ gene, was measured through a β-galactosidase assay, to assess the efficiency of adenovirus transfection and study the duration of LacZ gene expression. Virus dose response was studied to obtain optimal transfection condition. Transfection was also visually detected by staining the cells with X-gal, a chromogenic substrate of β-galactosidase. After transfection, cell viability was measured by MTS assay, a colourimetric method for determining the number of viable cells. For the in vivo work, the right Achilles tendons of 350-gram Sprague-Dawley rats were transected surgically. Ad5CMVntLacZ was introduced during healing. Transfection was assessed by staining tendon tissues and frozen sections of tendon tissue with X-gal. 106, 108 or 109 plaque-forming units (PFU) of Ad5CMVntLacZ were used for studying virus dose response. LacZ expression duration was studied at a dose of 108 PFU, by harvesting and staining tendon tissues at 1, 3, 4, 10 and 17 days post transfection. We compared the transfection efficiency of two different virus delivery approaches: (1) injecting virus into healing tendon directly, (2) soaking virus in a gelatin sponge, which was then implanted into healing tendon. The in vivo biodistribution of adenoviruses was studied in the healing tendon, muscles peripheral to the tendon and distal tissues.
Human rotator cuff tendon cells were successfully transfected without impairing cell viability, maximal β-galactosidase activity was at the dose of 1000 PFU / cell, the duration of LacZ expression was six days with a peak value at 24 hours. A transfection rate of 100% was obtained at the dose of 5000 PFU / cell. X-gal staining of cells confirmed successful transfection.
1000 PFU / cell was determined as the optimal dose for efficient in vitro transfection. Successful in vivo transfection by Ad5CMVntLacZ was also obtained in healing rat Achilles tendon as confirmed by X-gal staining, 0.4% of tendon cells were transfected at the dose of 106 PFU, the rate rose to 2% with 108 PFU and 3% with 109 PFU. The duration of in vivo LacZ expression was 17 days. Transfection efficiency was enhanced threefold and localization improved using a gelatin sponge to deliver the adenovirus.
The results of this study demonstrate that adenovirus can be used to deliver a gene of interest to cultured human rotator cuff tendon cells in vitro and healing tendon in vivo, with sponge implantation enhancing transfection efficiency in vivo. This work provides a good base for further research into the use of gene therapy to assist the healing of injured tendon.
Quan Dai
Australian Cancer Research Foundation Genetics Laboratory and Medical Genome Centre
The John Curtin School of Medical Research
Australian National University
PO Box 334, Building 54,
Mills Road, Canberra City ACT 2601
email: quan dot dai AT anu dot edu dot au
Thesis Abstract: Ecosystem Change and Campylobacter in Freshwaters: Case Studies from the Taieri and Motueka River Catchments
Rebekah Faye Eyles
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand 2004
New Zealand has a history of rapid ecosystem change since the arrival of humans, resulting in a predominantly agricultural landscape. This thesis investigates the influence of ecosystem (land use) change and other environmental variables on the human pathogen Campylobacter in two distinct river catchments of the South Island, New Zealand.
The Taieri catchment is predominantly rural, with land use including farming, cropping, market gardening, and forestry. The distribution of Campylobacter in freshwaters was investigated at a variety of spatial scales in the Taieri river catchment. First, Campylobacter concentrations in second order streams within distinct land uses were investigated, and dairy and deer farms showed relatively high concentrations compared to sheep farms and ungrazed tussock. Secondly a range of stream sizes (from second to fifth order) within two small agricultural catchments that encompass a mix of land uses were used to investigate the relationship between catchment development, stream order and Campylobacter and faecal coliforms. No significant correlation was detected between catchment development and Campylobacter, but a significant correlation between stream order and Campylobacter suggested a cumulative impact of land use on Campylobacter concentrations. The relationship between ecosystem change and Campylobacter was further investigated at mainstem (sixth order) sites on the lower Taieri River. Longitudinal variation in Campylobacter at these sites was related to inputs from small tributaries and agricultural drains, and outputs such as settling and cell death. Median concentrations of Campylobacter in the lower Taieri River were highest during summer months, when recreational use of the river is most common.
Campylobacter concentrations in the Motueka River were investigated in relation to both time (seasonality) and place (stream size). Seasonal effects on Campylobacter concentrations were investigated in a region with distinct wet and dry seasons, and a range of stream sizes were included, from small streams to major tributaries and main stem river sites. Campylobacter concentrations in the lower Motueka River were relatively low compared to the Taieri River, despite higher concentrations in tributaries associated with specific land uses (sheep and dairy farming), suggesting that dilution of contaminants by relatively clean water from forested sub-catchments was occurring. Campylobacter was isolated more frequently in winter and less frequently in summer in the Motueka Catchment. Results from the Motueka catchment suggest that public health benefits can arise from limiting agricultural development in catchments and protecting forested areas, particularly with respect to maintaining the microbial quality of rivers for drinking water and recreational activities.
A comparison of isolates of C. jejuni from freshwaters and clinical cases of campylobacteriosis (from the Taieri catchment and nearby Dunedin City) was carried out using both a phenotypic technique (Penner serotyping) and a molecular genetic technique (pulsed-field gel electrophoresis of DNA restriction fragments). The degree of overlap in strain types between isolates of C. jejuni from freshwaters and clinical cases indicates that freshwaters probably account for a significant proportion (10-20%) of sporadic cases of campylobacteriosis in the Taieri Catchment and Dunedin City.
Continuing ecosystem change through land use intensification in New Zealand may lead to further increases in microbial contamination of freshwaters, and an associated increase in waterborne enteric diseases such as campylobacteriosis.
Dr Rebekah Eyles
Department of Information Science
University of Otago
PO Box 56, Dunedin
New Zealand
email: reyles AT infoscience dot otago dot ac dot nz
Thesis Abstract: Investigation of Immune-Suppressive Genes Expressed by the Cotesia rubecula Bracovirus (CrBV)
Richard V. Glatz
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Adelaide, Australia 2004
The hymenopteran endoparasitoid, Cotesia rubecula, employs immune-suppression to overcome the internal defences of its host, Pieris rapae. Immune-suppressive activity arises from maternally secreted proteins and polydnavirus (PDV) particles, injected into a host larva with the parasitoid egg. The PDV associated with C. rubecula (CrBV) is unusual as it expresses only four genes (CrV1-CrV4) in P. rapae tissues and expression occurs only between approximately four and ten hours post-parasitisation (hpp). Previously, CrV1 was characterised and found to inactivate host haemocytes by causing disruption of their cytoskeleton, leading to abrogation of immune-associated processes. In this study, a cDNA library was constructed from parasitised P. rapae larvae and screened with CrBV DNA, leading to isolation of CrV2 and CrV3. Each gene was cloned and the resultant recombinant proteins used to produce anti-CrV2 and CrV3 antibodies.
CrV2 encodes a glycoprotein of approximately 40 kDa, which is secreted from infected haemocytes and fat body into serum. Comparison of CrV2 sequence with other known sequences revealed no significant homologies. CrV2 protein was detected in host larvae at 6 hpp, remaining in large amounts for a day and was declining by 48 hpp. A C-terminus coiled-coil region within CrV2 is suspected of involvement in formation of CrV2 trimers that were detected under non-denaturing conditions. CrV2 was visualised within haemocytes in large endosomes at 24 hpp. Although the function of CrV2 remains unclear, it appears to interact with haemocytes presumably to suppress their immune function.
CrV3 encodes a C-type lectin (CTL) homologue, also secreted from infected host haemocytes and fat body. Two CrV3 monomers (of approximately 14 and 17 kDa) were detected in parasitised larvae with the larger monomer being an N-glycosylated form of the smaller. CrV3 dimers and tetramers were also detected in ivivo. Recombinant CrV3 formed larger complexes and agglutinated ovine red blood cells, an activity that was Mn2+ and Mg2+ dependent but independent of Ca2+. CrV3-mediated hemagglutination was inhibited by EDTA but not by biological concentrations of 29 potential ligands tested. Interestingly, CrV3 is similar to invertebrate CTLs associated with humoral defence but not with previously isolated viral lectins. Further, CrV3 homologues were recently detected in bracoviruses from C. ruficrus and C. karyai, indicating that a novel CTL family is expressed by some Cotesia-associated PDVs. CrV3 probably interacts with a host haemolymph component associated with humoral immune defences.
CrV1 and Crp32 (an immune-suppressive C. rubecula ovarian protein) were used to produce recombinant Autographa californica baculoviruses (AcMNPVs), pathogens with putatively enhanced virulence in P. rapae. Bioassays investigated pathogenicity of wild-type AcMNPV in P. rapae (previously unreported) and the effect of Crp32 insertion. Although the proportion of larval deaths due to wild-type AcMNPV was significant, the slow rate of mortality indicated that P. rapae is only semi-permissive to AcMNPV. Crp32 insertion proved insignificant in terms of the proportion and rate of mortality. Given the semi-permissive nature of P. rapae, recombinant AcMNPVs expressing immune-suppressive and appropriate reporter genes may be useful for elucidating mechanisms of insect immunity and, more specifically, how CrBV acts to subvert these mechanisms in P. rapae.
Dr Richard V. Glatz
CSIRO Health Sciences and Nutrition
Kintore Avenue
Adelaide 5000
Australia
email: richard dot glatz AT csiro dot au
Thesis Abstract: The Role of Personal Values in Choice for Environmental Goods:\\Estimating Preferences for Non-Consumptive Use, Wildlife Viewing Among Student and Visitor Populations Segmented on their Personal Values
David K. Holdsworth
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy
University of Otago, Dunedin, New Zealand 2003
Preferences for wildlife viewing options were modelled for value segments among tertiary students and regional visitors to determine the relationship between consumer's values and their choices for environmental goods. Wildlife viewing was chosen as the choice subject, primarily as its complexity and nature should evoke personal values in the formation of choice criteria, and this product also exists under a range of management control reflecting both market and non-market non-consumptive use situations regionally.
A consumer's choice, characterised by the selection of a specific mix of product attributes was hypothesized to reflect that consumer's values, or motivational value types, described in Shalom Schwartz's, Universal Theory of Values. It was also surmised tourists [regional visitors] would maximise wildlife viewing by compensating access price and commercially managed site constraints for the certainty of viewing rare and endangered wildlife. The structure of personal values was postulated to be measurable and ordered the same across all populations, so student and visitor samples will have values structures similar in "explanatory power" for choices made by both.
Tertiary student and regional visitor samples were surveyed on their values and choice for options based on contingent and real wildlife viewing experiences existing around New Zealand. Their choices were analysed using conditional and mixed multinomial logic regression [MNL] to determine wildlife viewing preferences and preferences associated with particular motivational value types.
A significant interaction between values and choice for the wildlife viewing site attributes was found with respondents reporting particular types of values making characteristic choices for wildlife viewing sites. Science and environmental science students rating Universalism and Benevolence (Schwartz's Motivational Value Types) important in their lives, chose to visit a wildlife reserve, watch penguins, paying as little as possible. Commerce students rating Power, Achievement and Hedonism Motivational Value Types chose otherwise. Significantly different wildlife viewing site preferences were also found among visitors. A segment of middle aged and older women rating Universalism and Security values highly, preferred to visit a wildlife reserve site. Another segment of young Australians with Traditional values chose a coastal site.
Performance reversal of the survey choice model and associated values instrument was found from one sample to the other. The student conditional choice model used to analyse product attributes and choice explained less variance among the student's preferences, than did the visitor conditional model, Rho-squared of 0.1147 and 0.2489 respectively. The student ratings of values were consistent with Schwartz's Universal Structure of Values, while the visitor's ratings did not reflect that structure closely. This pattern influenced the performance of the mixed choice models, where the interaction of the respondent values and the wildlife viewing attributes improved the explained variance. Explained variance improvement (Rho-squared increasing from 0.1147 to 0.1529) was relatively large 34% with the student's mixed MNL regression model. By comparison explained variance improvement through including the visitors' values in a mixed model, resulted in only 4% increase in Rho-squared from 0.2489 to 0.2583. An improved measure of the visitor's values to couple with their choices would provide a strong values choice explanation.
David K. Holdsworth
Department of Marketing
School of Business
PO Box 56, Dunedin
New Zealand
email: dholdsworth AT business dot otago dot ac dot nz
Thesis Abstract: Environmental Ethics for the Future
Alexander K. Lautensach
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand 2003
Mounting evidence suggests that the Earth is facing an environmental crisis unprecedented in its scale and causation. It manifests itself mainly in an unprecedented rate of species extinction, chemical pollution and climate change. It threatens the continued well-being of humanity as well as much of the biodiversity of the planet. The causes lie in the exponential growth and consumption of the global human population and the resulting overshoot. As for most populations in overshoot, the erosion of source and sink limits and the emergence of density-dependent biological mechanisms of population control lead to dire consequences.
The crisis stems from behaviour of Homo sapiens which is incompatible with the basic requirements of a sustainable global society. Underlying human behaviour are beliefs, values and structural constraints that shape people's concepts of progress. Our individual concepts of progress serve as norms that help us decide on our actions and to evaluate the decisions of others. The emerging global culture manifests a particular dominant concept of progress that is based on the beliefs and values of the Dominant Social Paradigm and that represents in many respects a mere extension of the status quo and its quantitative expansion.
On closer inspection the beliefs and assumptions that underlie the dominant concept of progress turn out to be neither empirically justifiable nor conceptually consistent. The transition to sustainability necessitates their replacement with a New Environmental Paradigm which gives rise to the four goals of efficiency, restraint, adaptation, and structural reform. The value base of the dominant concept of progress causes even more significant problems, reducable to some fundamental flaws in anthropocentric ethics. The precepts of anthropocentrism by themselves leave the concept of the flourishing of humanity ill-defined; and the pursuit of anthropocentric values leads to outcomes that are unintended and undesirable, even from the view of the anthropocentrist. Ecocentric ethics, in contrast, avoids those problems. I propose that a compromise acceptable to both anthropocentrists and ecoccentrists is provided by an environmental ethic based on the Gaia theory.
The required widespread and deep change in people's ethics must make use of the processes of enculturation by which people tend to acquire values and of the means by which existing values may be modified. Considering the alternatives, the most promising approach to accomplish a cultural change of such magnitude seems to be through educational reform. I argue that the adoption by the learner of ecocentric values through formal education is possible, desirable and practical. Analysis of current educational practices also suggests considerable culpability regarding the crisis at hand, involving both the transmission of harmful or counterproductive values, beliefs and attitudes and the failure to elicit more productive learning outcomes.
Based on those shortcomings, and contingent on the required changes to people's concepts of progress and values, I propose a blueprint for curriculum reform. It incorporates six general aims in the forms of groups of learning outcomes. They include a concept of progress founded on sustainability, an ecocentrist environmental ethic, remediation of skill gaps, vision for the future that includes change and sustainable solutions, a non-parochialist view of environmental values and academic inquiry, and empowering the learner to take action. The goal is to ensure that learners acquire the moral, scientific, interpretive and emancipatory knowledge to build a sustainable future for humanity and its home.
Dr Alexander K. Lautensach
School of Biological Sciences
University of Auckland, New Zealand
Private Bag 92019
Auckland, NewZealand
email: a dot lautensach AT auckland dot ac dot nz
Thesis Abstract: Trauma and Mental Health among Vietnamese Australians in South Australia
Hoi Christian Manuel le
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy Flinders University, Australia 2002
Trauma and mental health are issues in the Vietnamese Australian community in South Australia. The aim of this study is to assess the trauma and the mental health status of Vietnamese Australian men and women in the Vietnamese community in South Australia. The objectives of the study were to: (1) assess and determine the current emotional and mental health condition of Vietnamese people in the Vietnamese community in South Australia; (2) identify the effects of trauma of violence, pre-migration, migration, post-migration, and resettlement issues on the emotional and mental health of Vietnamese people within the Vietnamese community; (3) identify and explore the attitude of participants towards violence and mental health problems or mental illness; (4) identify whether Vietnamese people seek professional help from counselling or mental health services; (5) identify any barriers Vietnamese people have to accessing counselling or mental health services; and (6) ensure that this study would be used to benefit those people who have experienced mental health problems or mental illness, trauma from violence, and the Vietnamese Australian community in general. The literature is extensively reviewed, appraised and discussed in regard to the history of violence, traditional Vietnamese values and culture, status of Vietnamese women, family violence in the Australian context, definition of violence and its effects on mental health and mental illness associated with violence. Attitudes of Vietnamese and Southeast Asians towards mental illness, the Vietnamese worldview, beliefs and practices are examined. Mental disorder (or mental illness), mental health problems and mental health are also examined and discussed. The study qualitatively explores focus group respondents' opinions, knowledge, attitudes and perceptions regarding the association between violence and mental health problems or mental illness, its impact on relationships and children, and social stigma factors which prevent people from seeking professional or psychiatric help. The study quantitatively examines the relationship between trauma from violence and mental health problems or mental illness. The study also assesses and determines the mental health status of Vietnamese Australian men and women in South Australia in general and its association with pre-migration, migration, and post-migration experiences such as trauma, loss of significant persons, life expectations, family issues, problems of adjustment and acculturation, community and emotional support, alcohol use and the post-traumatic stress disorder (PTSD) of those who experienced trauma from violence or abuse. Principal Component Analysis (Factor Analysis) of PTSD and psychological related symptoms was conducted and the association or correlation with traumatic experience such as the trauma of physical and emotional violence was examined.
Dr Hoi Christian Manuel Le
Department of Psychiatry
School of Medicine, Faculty of Health Science
Flinders University
Adelaide 5042
Australia
Thesis Abstract: Wetlands for Minewaters - Constructed Wetland Systems for Biological Treatment of Mining Wastewaters in Western Tasmania
Michael J. Lichon
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Tasmania, Hobart, Tasmania 2000
Mining and lime-treated mineral processing wastewaters from the Hellyer Zn/Pb Mine in western Tasmania, bearing Pb after tailings dam treatment, pass through a series of pilot wetlands. This field-based study focusSes on identifying mechanisms behind wetland removal of residual Pb from wastewaters, performance improvement and catchment issues. The background, aims and significance of the industry-sponsored study are outlined. The study site for this applied research project is described and defined. Environmental uncertainties and practical challenges dictated the need for field-based observations supplemented by limited scope experimentation. Problems with sampling are identified and overcome by innovation.
Surprisingly, wastewater Pb sinks in wetlands almost exclusively in the form of PbS in the mud. The 50% suspended fraction of Pb uptake is removed from wastewaters by sedimentation, dependent on quiescent wetland residence time.
Several native emergent wetland plants suitable for treatment of mine wastewaters are identified using several criteria, and bulk and experimental plantings. These include Eleocharis, Juncus, Restio and Triglochin. The wetland plants contribute little to direct removal of Pb from wastewaters; rather, they provide structural stability and serve as in situ photosynthetic generators of organic matter. Falling into the mud, the organic matter maintains a decomposer-rich, low-Eh anaerobic mire, and fuels a microbial consortium including three genera of sulfate-reducing bacteria (SRB). By dissimilatory respiration, SRB reduce sulfate and thiosalts diffusing into the mud from the wastewaters to H2S. The "dissolved" (filterable) 50% fraction of wastewater Pb uptake precipitates as PbS by chemical demand of sulphide acting on various complexed and colloidal forms of Pb present in the wastewater stream. This continues to a lesser degree downstream into the catchment with streambed colonisation by SRB consortia.
Wetland operating parameters are measured and evaluated. Key changes to mine site operation and wetland management, including optimising conditions for maximum SRB activity, waste co-treatment and improving wetland hydrology, are implemented or recommended to enhance wetland treatment performance. The river system affected by mine operations is examined by applying principles of total catchment management. Catchment areas need a multidisciplinary approach and cooperative, proactive management by stakeholders to minimise disturbance, degradation and water quality problems, and to apply remedial strategies.
Dr Michael J. Lichon
School of Plant Science
University of Tasmania
Hobart, Tasmania 7006
Australia
email: mlichon AT postoffice dot utas dot edu dot au
Thesis Abstract: The Influence of a Back Support Harness on the Spinal Movement and Force Profile of Sheep Shearers
Stephan Milosavljevic
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand, 2004
The body of epidemiological data suggests that occupations with a heavy work classification carry risk of low back injury. Asymmetric movement coupling and repetitive loading in flexion are also considered to be components of undesirable functional working postures. Biomechanical analysis and literature guidelines suggest that occupational lumbo-sacral compressive forces exceeding 3400 Newtons and anterior shear forces exceeding 500 Newtons should be considered as indicators for a need for workplace intervention. The aim of this research was to investigate the 3D dynamic movement and force profiles in the lumbar spine of a sample of sheep shearers and to determine the influence of professional skill and the use of a back harness on these movement and force profiles.
A kinematic and kinetic analysis of the shearing tasks performed by twelve experienced shearers was undertaken in an industry standard shearing shed. Anthropometric, survey and 3D motion analysis data were gathered in order to construct the parameters for analysis. Surface mounted retro-reflective markers placed on sufficient trunk parameters defined three linked segments: pelvis, pumbar and pead, prms, prunk (HAT). A 3D, link segment, top down, inverse dynamics approach was used to construct the kinematic and kinetic profiles. Based on an expert driven qualitative assessment three specific shearing tasks were defined and prioritised for primary analysis.
Functional movement profiles demonstrate complexity and asymmetry of movement about three orthogonal axes identified at the thoraco-lumbar and lumbo-sacral joints. Flexion is not surprisingly a consistent movement during this task however lateral flexion and rotation couple with flexion in ways that suggest individual variability is a factor. A high level of professional skill appears to reduce the level of asymmetrical movement - particularly spinal rotation. The spinal force profile demonstrates considerable compressive and shear forces that are close to occupational health recommended action limits. The use of the back harness substantially reduces these forces.
The shearing occupation demonstrates complexity of movement coupling during a biomechanical analysis. An awareness of the potential for such task complexity should challenge the clinician to consider the manner in which we investigate spinal movement. Simplistic planar models may at times be insufficient and movements may need to be clinically coupled or combined in a manner that approaches the functional problem. The results of this study indicate that occupational skill is associated with reduced asymmetric movement and that a back support harness can substantially reduce spinal compressive and shear forces. Recommendations are made for the shearing industry, occupational health clinicians and for future research.
Stephan Milosavljevic PhD
Associate Dean of Research and Postgraduate Studies
School of Physiotherapy
University of Otago
PO Box 56, Dunedin
New Zealand
email: smilosavljevic AT gandalf dot otago dot ac dot nz
Thesis Abstract: Do Transtheoretical Model Measures Predict Stage Transitions for Smoking Cessation? Studies of Callers to a Quitline
Cathy J. Segan
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy La Trobe University, Australia 2003
The psychological question posed in this thesis is how do people move from being smokers with little interest in quitting, to exsmokers quitting for some time. Evaluation of a popular and influential health behaviour change model, the Transtheoretical Model (TTM), is used to examine this issue. Central to the TTM is the notion that individuals progress through a series of motivational stages of change in attempting to modify behaviour. These stages (and their definitions for smoking cessation) are precontemplation (not seriously considering quitting in the next 6 months), contemplation (seriously considering quitting in the next 6 months, or planning to quit in the next 30 days but has not made a quit attempt in the last year), preparation (planning to quit in the next 30 days, and has made a quit attempt in the last year), action (quit for at least 24 hours), and maintenance (quit for more than 6 months). Other model constructs including ten processes of change (which consist of five experiential and five behavioural strategies for change), the pros and cons of smoking, temptations to smoke and confidence to resist temptations are purported to predict transitions between the stages of change. Prospective tests of stage transitions provide better identification of the factors that cause people to move from one stage to the next, and can inform the debate as to whether behaviour change is better conceptualised as a stage or a continuum process.
There have been few prospective tests of stage transitions. This thesis aims to critically examine stage transitions, with a focus on transitions to and from the action stage of change. Four empirical papers are presented which stem from two independent studies of callers to a quitline. Three papers tested stage transitions. The findings demonstrated little support for the TTM's few clearly specified predictions regarding stage transitions and question the adequacy of the stage definitions themselves. Different factors predicted progression at different stages thereby supporting the notion of stages, or at least nonlinearities in the change process. The fourth paper highlights an important methodological issue in the testing of stage models, specifically the need to control for stage of change when examining whether the change processes predict cessation. Together, the findings raise concerns about the internal validity and predictive utility of the TTM, and thus its appropriateness as a framework on which to develop smoking cessation interventions.
Dr Cathy Segan
Senior Research Officer
VicHealth Centre for Tobacco Control
The Cancer Council Victoria
1 Rathdowne St
Carlton, Victoria 3053
email: Cathy dot Segan AT cancervic dot org dot au
Thesis Abstract: The Development of Columnar Peds in a Texture Contrast Soil in the Pilliga State Forests, Northwestern New South Wales
Peter Walsh
Abstract of a Thesis submitted for the Degree of Master of Science (Research) Macquarie University 2003
A common reaction among the number of scientists from whom I sought advice and opinion during my candidature for this degree was one of surprise upon learning of the nature of my research topic. These professionals all had one thing in common; they had at some stage in their careers conducted research in pedology, a scientific discipline devoted to the study of the genesis, distribution and composition of soils as they occur naturally. At first, I interpreted their reaction as being contemptuous of my study, insofar as why was I wasting my time in an area that no longer required research, as all the facts were known. Feeling somewhat defensive, I asked one of them to explain why discussion of my topic continually elicited this same response. Much to my relief it was not disdain that was being expressed, but simply an observation that studies of this kind are rare today due to the low status afforded pedology within contemporary Australian scientific and academic institutions. Whilst the level of research in pedology may have declined over the past few decades, the number of issues still to be resolved has not.
This thesis explores one of these issues, the genesis of columnar peds within a soil type commonly referred to as a soloth, a texture contrast soil that in this study has developed in situ from the weathering of a lithic facies of the Pilliga Sandstone. The relative importance of joint inheritance, shrink-swell and dispersion in a bedrock controlled environment was assessed, and it was found that a shrink-swell system is superimposed on top of a larger fracture system in the saprolite that is inherited from jointing in the underlying sandstone. As well as exerting a significant structural control on the development of columnar peds in the saprolite, the underlying sandstone also exerts a significant mineralogical control on the in situ weathered soil. Tentative models for the development of the fracture system which defines the sides of the columnar peds and the rounding of their tops are presented.
Peter Walsh
Research and Development Division
State Forests of NSW
PO Box 100
Beecroft, NSW 2119
Thesis Abstract: Transfers of Marketing Knowledge in Acquisitions
Thorsk G. Westphal
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand 2004
This study was motivated by, and responded to, two recent trends that have captured the attention of academia, business, and the public worldwide. The global shift towards a knowledge economy and the increasing importance of knowledge as an organisational asset and source of competitive advantage have set off an unprecedented wave of mergers and acquisitions that has spread across the globe over the last decade. Frequently undertaken to acquire know-how, many of these deals have failed to effect the post-acquisition knowledge transfers needed to achieve the desired knowledge-based synergies. However, despite these phenomena and the obvious importance of knowledge transfers to acquisition success, very little empirical research has examined the potential influences and outcomes of such transfers; none has studied both in conjunction.
It was, therefore, the primary aim of this study to develop an integrative framework of influences and outcomes of knowledge transfers in acquisitions. Specifically, this study focused on the transfers of marketing knowledge between the marketing departments of German acquiring firms and their German or overseas target firms.
Through the conceptual integration of the knowledge management, mergers and acquisition, and marketing literatures, this study developed a preliminary model of influences (i.e., knowledge characteristics, organisational characteristics, acquisition characteristics, and individual characteristics) and outcomes (i.e., transfer-related marketing synergies). This model was subsequently tested and modified through exploratory interviews with marketing executives of German multinational acquirers. The revised model, in turn, was then empirically examined through a large-scale questionnaire survey among German firms that had acquired other German or overseas acquisitions between 1996 and 2000.
Finally, statistical analysis of the survey data found that post-acquisition knowledge transfers are: a) hindered by the tacitness yet promoted by the specific and complementary nature as well as the perceived usefulness of the knowledge to be transferred; b) hindered by cultural and positioning dissimilarity between the firms yet promoted by their product-market dissimilarity; c) promoted by the prevalence of information-sharing norms in the firms' workplace as well as by the acquirer's establishment of group-based work arrangements and reward systems and the absence of managerial coercion, d) promoted by the acquirer's procedural fairness towards the target staff during the acquisition integration process as well as the target's post-acquisition resource dependence; and e) promoted by the individual staff members' professional respect and personal affinity for their new colleagues, their welcoming attitude towards the acquisition itself, their positive perception of the quality of the relationship between them and their new colleagues, and their relatively stronger identification with new, combined organisation than their old one.
As none of these variables had been empirically tested in the context of post-acquisition knowledge transfers before, this study's findings contributed to, and are expected to find application in, the bodies of literature from which these concepts were taken. In this respect, the study's contribution to the knowledge transfer and mergers and acquisition literatures are emphasised. These are discussed in the thesis.
Dr Thorsk G Westphal
65 Hugo-Johnston-Drive
Penrose, Auckland
NewZealand
email: twestphal AT nz dot loreal dot com
Thesis Abstract: Development and Perinatal Maintenance of the Neuromuscular System in Neurotrophin-3 null Mutant Mice
Adele Glyn Woolley
Abstract of a Thesis submitted for the Degree of Doctor of Philosophy University of Otago, Dunedin, New Zealand 2003
The primary structure of the polypeptide neurotrophin-3 (NT3), a member of the neurotrophin family, was first identified in 1990 (Hohn, Liebrock et al. 1990). Transgenic mice without a functional gene for NT3 do not develop proprioceptive neurons within the dorsal root ganglia and thus lack both group Ia afferents and muscle spindles. Additionally, mice with a homozygous deletion of the NT3 gene have a significant reduction in the number of sympathetic neurons within the superior cervical ganglia. The number of alpha motoneurons is reported as being unaffected (Ernfors, Lee et al. 1994), and no other significant defects have been reported within the neuromuscular system. This thesis critically examines the development of the neuromuscular system in NT3 mutant animals. Using stereological analysis, we confirm an earlier report of gamma motoneuron loss within the ventral horn of the spinal cord in NT3 null mutant (-/-) animals (Kucera, Ernfors et al. 1995), but also establish that the size of the alpha motoneuron cell body is significantly reduced in the newborn (-/-) animals, while the number of alpha motoneurons is unaffected (Woolley, Sheard et al. 1999). Subsequent quantification of myofibre number in soleus and Extensor digitorum longus (EDL) muscles at birth (P0) using electron microscopic methods confirms that the target (muscle) size is also significantly reduced in these (-/-) animals, as compared to their wild type (+/+) littermates. The number of myofibres continues to increase postnatally in both the (-/-) and (+/+) animals, but the total number of myofibres at postnatal day seven (P7) is still significantly less in the (-/-) than in the (+/+) animals. Thus, the reduction in target size seen at P0 is partially due to a delay in development, but there is also a final deficit in the formation of the myofibres. At the neuromuscular junction, the number of small axon profiles found at each endplate is increased at P0, resulting in an increase in the overall total number of axon profiles per endplate. Furthermore, the occupancy of the postsynaptic membrane by the terminal axon profiles is significantly less in the muscles of P0 null mutant animals, as compared to their wild type littermates, suggesting a disturbance of the neuromuscular relations during this perinatal period.
Other morphological changes are described within the muscles of a small number of older (P3, P4 and P7) (-/-) animals. These include a failure of the neuromuscular junctions to be maintained postnatally. Neuromuscular junctions at P3 are sparse and appear to be confined to areas of the muscle in the immediate vicinity of large intramuscular nerve branches. The remaining junctions exhibit substantial abnormalities, including the degeneration of some of the terminal axon profiles. The total number of axon profiles per endplate is less than in the P0 null animals (p < 0.05) and the majority of axon profiles within the endplates are of medium size, suggesting that a progressive postnatal withdrawal of small motor nerve terminals from the muscle endplate has taken place. There is also evidence of both cytoplasmic darkening and degeneration of a significant number of terminal Schwann cells. By P4, and also within the muscles of the P7 null mutant animals examined, there is no evidence of any neuromuscular junctions within either EDL or soleus muscle, despite the continuing presence of peripheral axons at the point of entry into the muscle. The common peroneal nerve of the P3 null mutant animals shows gross abnormalities of the myelin, together with condensation of the axoplasm, and dense neurofilament.
This evidence suggests that NT3 is critical for the postnatal maintenance of the alpha motoneuron. Three possible mechanisms of action are discussed, the first being that NT3 is directly involved in the support of the motoneuron. The second possibility is that NT3 is directly involved in the support of the Schwann cell. Lack of primary support for the Schwann cell during the postnatal period would result in a secondary motor neuropathy and would explain the motor deficits seen within the (-/-) animals. The third possibility is that there is a reduction in the activity level of the neuromuscular system due to the absence of proprioceptive input, and that this reduced activity gives rise to the abnormalities seen.
References
Ernfors, P., Lee, K.F. et al. (1994). "Lack of neurotrophin-3 leads to deficiencies in the peripheral nervous system and loss of limb proprioceptive afferents." Cell 77(4): 503-12.
Hohn, A., Liebrock, J. et al. (1990). "Identification and characterisation of a novel member of the nerve growth factor/brain-derived neurotrophic factor family." Nature 344: 339-341.
Kucera, J., Ernfors, P. et al. (1995). "Reduction in the number of spinal motor neurons in neurotrophin-3- deficient mice." Neuroscience 69(1): 321-30.
Woolley, A., Sheard, P. et al. (1999). "Alpha motoneurons are present in normal numbers but with reduced soma size in neurotrophin-3 knockout mice." Neurosci. Lett 272(2): 107-10.
Adele Glyn Woolley
Developmental Biology Research Group
Department of Anatomy and Structural Biology
Otago School of Medical Sciences
PO Box 913, Dunedin
New Zealand
email: adele dot wooley AT stonebow dot otago dot ac dot nz