Calcium (Ca) depletion and increased bioavailability of aluminum (Al) are potential consequences of soil acidification caused by acidic deposition and other anthropogenic factors. Tree declines are associated with base cation depletion and increased Al toxicity in forest soils in North America, Europe, and Asia. Changes in soil Ca and Al availability may lead to increased oxidative stress and disruptions in carbohydrate relationships in forest trees, as well as to substantial alterations in the capacity for enzymatically controlled processes of decomposition and mineralization in forest soils. Assessments were made to determine if forest systems are prone to disruption associated with altered Ca and Al bioavailability. Foliar elemental concentrations, foliar antioxidant enzyme activities, foliar and woody shoot carbohydrates were measured in sugar maple (Acer saccharum, Marsh.), and soil extracellular enzyme activities (EEA) were assayed at a long-term nutrient perturbation study (NuPert) in the Hubbard Brook Experimental Forest, New Hampshire, USA. Treated plots received Ca to increase soil Ca above ambient depleted levels or Al to further reduce Ca availability. Additions of Ca to soil are associated with greater Ca concentrations in foliage compared to leaves from trees from control and Al-addition plots. Soil Aladditions are associated with lower foliar phosphorus concentrations in comparison with foliage from trees in Ca-addition plots. Additions of Al to soil are associated with higher antioxidant enzyme (glutathione reductase and ascorbate peroxidase) activities in foliage and lower shoot sugar (total sugars, sucrose, glucose and fructose) concentrations relative to trees in Ca-addition and control plots. Al accumulations in distal tissues likely triggered toxicity responses reported for leaves and stems. Soil EEA results highlight treatment-induced alterations to soil processes. Across soil enzyme systems, EEA levels are greatest in Al-addition soils in fall, but are elevated in Caaddition soils in spring compared with ambient conditions. Seasonal differences in EEA levels suggest a differential influence of soil treatments on specific soil communities. Within this native, mature northern hardwood forest, early indications of response in foundation species to Ca and Al manipulation are detected including Al-induced oxidative stress and resulting carbohydrate irregularities in sugar maple trees, and substantial seasonal swings in soil EEA: processes that could foreshadow broader ecosystem alterations as anthropogenic disruptions of soil Ca and Al availability continue.

Title page, table of contents and summary only. The complete thesis in print form is available from the University of Adelaide Library. / The Acidic Rich family of RS Domain proteins (ARRS) is defined by both the presence and arrangement of conserved domains within 2 family members. Conserved regions include an RS domain, zinc finger domain, RNA binding motif and a C terminal acidic rich region. Two conserved motifs within the RRM of ARRS proteins have been defined that are not found in the RRM of other RNA binding proteins. Peri implantation stem cell 1 (pscl), the founding member of this family, was originally identified as a developmental marker differentially expressed between the Inner Cell Mass and primitive ectoderm of the mammalian embryo. Psc1 RNA is differentially up-regulated in the post gastrulation embryo and the adult, with high mRNA levels in lung, brain and kidney, and low level expression in other tissues. Comparative analysis of Psc1 to RS domain proteins known to function in mRNA processing, such as SC35 and ASF/SF2, has shown it colocalises to characteristic nuclear speckles. However, in contrast to SR proteins, Pscl localises to additional regions in the nucleus, not containing SR proteins, and to punctate regions in the cytoplasm termed cytospeckles. Further, in the absence of transcription, Psc 1 localises to regions in the nucleus which exclude nuclear speckles. Finally, unlike SC35 and ASF/SF2, which move rapidly in and out of nuclear speckles, FRAP assays show Psc1 is tethered within the nucleus. Analysis of Psc1 domain contribution to subcellular localisation and mobility shows the RRM to be both necessary and sufficient for Psc 1 cytospeckle localisation and is responsible for the nuclear tethering of Pscl. The RS domain of Pscl acts as a nuclear localisation signal and contributes to nuclear speckle localisation. The C terminal of Psc I localises with microtubules and is proposed to mediate Psc 1 cytoskeletal association. The expression of the Drosophila acidic rich RS domain protein (NP609976) is developmentally regulated in the same manner as Pscl, it has a nuclear localisation profile identical to Psc 1 and also localises to speckles in the cytoplasm, all of which support a conserved evolutionary role for Pscl and the ARRS protein family in mRNA processing and trafficking both in the nucleus and in the cytoplasm. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1236604 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2006

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A programme of field sampling was undertaken to quantify total carbon fluxes (DOC, POC, HCO3, free CO2 and CH4) from peatland catchments in Glen Dye, NE Scotland and Plynlimon, Mid-Wales. This was integrated with temporal and spatial sampling to investigate controls on contrasting concentrations and fluxes and to determine carbon sources or sinks within the stream system. Microcosms containing radiolabelled ( 14C) biofilms were also used to investigate removal of DOC from streamwater. Carbon fluxes from acidic peatlands were dominated by DOC (115-215 kg C ha-1 yr-1) and POC (8.15-97.0 kg ha -1 yr-1). In the majority of headwaters studied, DIC was exported as free CO2 (2.62-8.49 kg ha-1 yr -1). Methane-C fluxes at the outlets of catchments were <0.01 kg ha-1 yr-1. Small-scale (diurnal) temporal variations in free CO2, HCO3- and pH at the NE Scotland catchments were small compared to more productive systems; DOC showed no diurnal fluctuations. In addition, diurnal patterns were masked by marked variations in discharge. Small-scale downstream spatial changes in Brocky Burn, NE Scotland and the Upper Hafren, Mid-Wales showed that variation in climate, in particular precipitation, was also a major controlling factor on concentrations and fluxes of the different forms of carbon. However, the actual amount of carbon stored within the soils acted as an initial control on the potential DOC load within the streamwater. A peatland stream continuum linked to terrestrial carbon cycling is presented. Initially terrestrial inputs of DOC, POC, free CO2 and CH 4 dominated the upper headwaters. The soil-stream linkage was progressively reduced downstream due to autochthonous and atmospheric factors. A critical area in the peatland stream continuum occurred approximately 1 km downstream from the gaseous carbon-rich peats.

Sepiolite is a clay mineral, a complex magnesium silicate, a typical formula for which is (OH2)4(OH)4Mg8Si12O30•8H2O. It is formed by blocks and cavities (tunnels) growing in the direction of the fibres. The tunnels, 3.7 x 10.6 Å in cross-section, are responsible for the high specific surface area and sorptive properties of sepiolite. The co-intercalation of 3-methyl cyclohex-2-en-1-one (MCH), the Douglas-Fir beetle anti-aggregation pheromone, with methanol, ethanol, acetone, or benzene into sepiolite tunnels was studied. The resulting nanohybrid materials were characterized by means of various techniques, such as multinuclear solid-state NMR spectroscopy, porosity studies and Thermal Gravimetric Analysis (TGA). This was done in the hope of obtaining slow and controlled release of MCH from the sepiolite tunnels. It was demonstrated by 13C MAS NMR (carbon-13 magic angle spinning nuclear magnetic resonance) that at room temperature there are two different MCH molecules: one MCH inside the tunnels and the other one outside the tunnels of the sepiolite. Heating nanohybrid materials at 60˚C for 20 hours removes the external MCH molecules from the sepiolite. 13C MAS NMR showed that by further heating nanohybrid materials at 120˚C for 20 hours, methanol, ethanol, or acetone peaks were greatly reduced; however, the benzene peak was not reduced. To better understand how benzene acts inside sepiolite, intercalation of d6-benzene, and co-intercalations of d6-benzene with MCH and d6-benzene with pyridine into sepiolite tunnels were carried out, and these samples were studied by the same techniques. Another technique was used in order to see whether the slow and controlled release of MCH from the sepiolite tunnels could be obtained: sepiolite-MCH nanohybrids were treated with 20 ml of 0.5 M HCl solution. It was found that when 1 gram of MCH-sepiolite sample was acid treated at room temperature, about 35% of intercalated MCH was removed from the sepiolite. The role of sepiolite clay was also studied in Maya-Blue representative structure sepiolite-indigo adduct. It is known that upon heating the sepiolite and indigo mixture, the stability that is present in Maya-Blue is achieved. It is still a mystery, however, how exactly indigo and sepiolite interact with each other.

Sepiolite is a clay mineral, a complex magnesium silicate, a typical formula for which is (OH2)4(OH)4Mg8Si12O30•8H2O. It is formed by blocks and cavities (tunnels) growing in the direction of the fibres. The tunnels, 3.7 x 10.6 Å in cross-section, are responsible for the high specific surface area and sorptive properties of sepiolite. The co-intercalation of 3-methyl cyclohex-2-en-1-one (MCH), the Douglas-Fir beetle anti-aggregation pheromone, with methanol, ethanol, acetone, or benzene into sepiolite tunnels was studied. The resulting nanohybrid materials were characterized by means of various techniques, such as multinuclear solid-state NMR spectroscopy, porosity studies and Thermal Gravimetric Analysis (TGA). This was done in the hope of obtaining slow and controlled release of MCH from the sepiolite tunnels. It was demonstrated by 13C MAS NMR (carbon-13 magic angle spinning nuclear magnetic resonance) that at room temperature there are two different MCH molecules: one MCH inside the tunnels and the other one outside the tunnels of the sepiolite. Heating nanohybrid materials at 60˚C for 20 hours removes the external MCH molecules from the sepiolite. 13C MAS NMR showed that by further heating nanohybrid materials at 120˚C for 20 hours, methanol, ethanol, or acetone peaks were greatly reduced; however, the benzene peak was not reduced. To better understand how benzene acts inside sepiolite, intercalation of d6-benzene, and co-intercalations of d6-benzene with MCH and d6-benzene with pyridine into sepiolite tunnels were carried out, and these samples were studied by the same techniques. Another technique was used in order to see whether the slow and controlled release of MCH from the sepiolite tunnels could be obtained: sepiolite-MCH nanohybrids were treated with 20 ml of 0.5 M HCl solution. It was found that when 1 gram of MCH-sepiolite sample was acid treated at room temperature, about 35% of intercalated MCH was removed from the sepiolite. The role of sepiolite clay was also studied in Maya-Blue representative structure sepiolite-indigo adduct. It is known that upon heating the sepiolite and indigo mixture, the stability that is present in Maya-Blue is achieved. It is still a mystery, however, how exactly indigo and sepiolite interact with each other.

A study of the atom transfer radical polymerisation (ATRP) of water-soluble, acidic, monomers was carried out in aqueous media. The ATRP of sodium methacrylate (MAANa) produced polymers with controlled molecular weights and narrow polydispersities (Me/M, - 1.3) at 90°C. This is the first reported example of direct polymerisation of an acidic monomer via ATRP. Previously, such acidic polymers were produced by polymerisation of protected monomers. In this thesis, copper(l) bromide and iron(II) bromide were investigated as ATRP catalysts. Both were found to be effective when solubilised by 2,2'-bipyridine (bipy). Monomer conversions between 75 and 85 % were obtained in the presence of Cu(l)Brlbipy, and conversions as high as 94 % were obtained in the presence of Fe(II)Br2Ibipy. Kinetic studies carried out on the ATRP of MAANa using the CuBrlbipy catalyst and an oligo(ethylene glycol)-based initiator indicated that polymerisation proceeded via first order kinetics with respect to monomer consumption, and that molecular weight increased linearly with conversion. This is as expected for a living polymerisation. At approximately 75 - 85 % conversion, however, premature termination occurred. Both bromine microanalyses and 'n and 13CNMR studies indicated that the halide-capped polymer chain-ends undergo HBr elimination. Low molecular weight « 10,000 g mol") MAANa homopolymers and oligo(ethylene glycol)-sodium methacrylate block copolymers (PEG-b-PMAANa) were examined as possible macro initiators for the ATRP of sodium 4-styrenesulfonate (SSNa), potassium 3- sulfopropyl methacrylate (SPMAK) and sodium allyl sulfonate (SAS). PEG-b-PMAANa was found to initiate the ATRP of SSNa, yielding a polymer with controlled molecular weight and a polydispersity of 1.23. Initiation of the ATRP of SPMAK and SAS was less successful. This was likely due to the loss of functionality of the MAANa-based polymers. Block copolymers were obtained, however, by macroinitiating the aqueous ATRP of MAANa using a monomethoxy-capped oligo(ethylene glycol) methacrylate homopolymer. Successful ATRP of MAANa was also achievable at ambient temperatures in the presence of a co-solvent, 2-(dimethylamino)ethanol, DMAE. DMAE appears to dramatically increase the rate of polymerisation whilst still maintaining control when used in equimolar quantities (relative to the monomer). Polymers with predetermined molecular weights and narrow polydispersities were produced in good yield (up to 86 % conversion) within five minutes at 20°C. The ATRP of other hydrophilic monomers was also investigated, albeit in less detail. These monomers included sodium acrylate, mono-2-(methacryloyloxy)ethyl succinate, 2- hydroxyethyl acrylate, itaconic acid, and 2-acrylamido-2-methyl-propanesulfonic acid. Generally less control was achieved for such syntheses than for the ATRP of MAANa.