The thesis studied the biological control of woolly aphid (Eriosoma lanigerum Hausm.) using European earwig (Forficula auricularia L.) in an Australian apple orchard IPM program. Woolly aphid populations were monitored over the 1995/96 and 1996/97 growing seasons, completing a four year study of the pest's status and management under IPM programs at Bathurst in the Central Tablelands of NSW. Woolly aphid infestation in 2 IPM treatments, based on alternative control techniques for codling moth (Cydia pomonella L.), namely mating disruption and fenoxycarb, were compared with a conventional insecticide azinphos-methyl program. Further, the thesis studied the toxicity, to adult European earwigs, of chemicals commonly used in Australian apple orchards. The pesticide alpha-cypermethrin is highly toxic to weevil spp. and is used by apple growers in Western Australia for their control, but it is also toxic to earwigs. This trial investigated the potential of alpha-cypermethrin to disrupt the biological control of woolly aphid. Following a single application as a butt spray, alpha-cypermethrin suppressed the number of earwigs in apple trees for 14 weeks. The single application did not reduce earwig numbers to the extent that the biological control of woolly aphid was lost, however a full season program with applications every 14 to 21 days to all trees, as recommended to control weevils, within an orchard is likely to be very disruptive. The research also studied the control of woolly aphid using insecticide root-soil drenches. Imidacloprid provided excellent control of woolly aphid for 3 seasons. Pirimcarb provided some suppression of woolly aphid during the first season, but not in subsequent seasons. Chlorpyrifos and vamidothion failed to control woolly aphid in any season. / Doctor of Philosophy (PhD)

Exposure to air contaminants is significantly associated with both short-term and long-term health effects. However, the precise mechanisms that derive such effects are not always understood. While an extensive background database from in vivo toxicological studies have been developed, most toxicity data is from oral and dermal chemical exposures rather than inhalation exposure. There is a need to explore new alternative approaches to provide toxicity information particularly on this technically demanding area. This research explores the potential of in vitro methods for toxicity assessment of workplace air contaminants. A tiered approach for in vitro toxicity testing of workplace contaminants was designed in which appropriate air sampling and exposure techniques were developed. A diversified battery of in vitro assays including the MTS (tetrazolium salt, Promega), NRU (neutral red uptake, Sigma) and ATP (adenosine triphosphate, Promega) and a multiple human cell system including: A549- lung derived cells; HepG2-liver derived cells, and skin fibroblasts were used. Primarily the application and merits of in vitro methods for prediction of toxicity of selected workplace contaminants including Ammonium hydroxide, Cadmium chloride, Cobalt chloride, Formaldehyde, Glutaraldehyde, Manganese chloride, Mercuric chloride, Sodium dichromate, Sulphureous acid and Zinc chloride was confirmed. To study the toxicity of airborne contaminants an indirect exposure method was established using air sampling techniques followed by static and dynamic direct exposure methods by culturing cells on porous membranes to reveal representative data relating to human airborne exposures. The static method enabled the measurement of an airborne IC50 (50% inhibitory concentration) value for selected volatile organic compounds (VOCs) including: Xylene (IC50 = 5,350-8,200 ppm) and Toluene (IC50 = 10,500- 16,600 ppm) after 1 hr exposure. By implementing the dynamic method, airborne IC50 values were calculated for gaseous contaminants including: NO2 (IC50 = 11 ?? 3.54 ppm; NRU), SO2 (IC50 = 48 ?? 2.83 ppm; ATP) and NH3 (IC50 = 199 ?? 1.41 ppm; MTS). A higher sensitivity of in vitro methods was observed compared to in vivo published data. A range of in vitro bioassays in conjunction with exposure techniques developed in this thesis may provide an advanced technology for a comprehensive risk assessment of workplace air contaminants.

<p>Metal contaminated stormwater, i.e. surface runoff in urban areas, can be treated in percolation systems, ponds, or wetlands to prevent the release of metals into receiving waters. Plants in such systems can, for example, attenuate water flow, bind sediment, and directly accumulate metals. By these actions plants affect metal mobility. This study aimed to examine the accumulation of Zn, Cu, Cd, and Pb in roots and shoots of plant species common in stormwater areas. Furthermore, submersed plants were used to examine the fate of metals: uptake, translocation, and leakage. Factors known to influence metal accumulation, such as metal ion competition, water salinity, and temperature, were also examined. The following plant species were collected in the field: terrestrial plants – <i>Impatiens parviflora</i>, <i>Filipendula ulmaria</i>, and <i>Urtica dioica</i>; emergent plants –<i> Alisma-plantago aquatica</i>, <i>Juncus effusus</i>, <i>Lythrum salicaria</i>, <i>Sagittaria sagittifolia</i>, and <i>Phalaris arundinacea</i>; free-floating plants – <i>Lemna gibba</i> and <i>Lemna minor</i>; and submersed plants – <i>Elodea canadensis</i> and <i>Potamogeton natans</i>. Furthermore, the two submersed plants, <i>E. canadensis</i> and <i>P. natans</i>, were used in climate chamber experiments to study the fate of the metals in the plant–water system.</p><p>Emergent and terrestrial plant species accumulated high concentrations of metals in their roots under natural conditions but much less so in their shoots, and the accumulation increased further with increased external concentration. The submersed and free-floating species accumulated high levels of metals in both their roots and shoots. Metals accumulated in the shoots of <i>E. canadensis</i> and <i>P. natans</i> derived mostly from direct metal uptake from the water column.</p><p>The accumulation of Zn, Cu, Cd, and Pb in submersed species was in general high, the highest concentrations being measured in the roots, followed by the leaves and stems, <i>E. canadensis</i> having higher accumulation capacity than <i>P. natans</i>. In <i>E. canadensis</i> the Cd uptake was passive, and the accumulation in dead plants exceeded the of living with time. The capacity to quickly accumulate Cd in the apoplast decreased with successive treatments. Some of the Cd accumulated was readily available for leakage. In <i>P. natans,</i> the presence of mixtures of metal ions, common in stormwater, did not alter the accumulation of the individual metals compared to when presented separately. It is therefore, proposed that the site of uptake is specific for each metal ion. In addition cell wall-bound fraction increased with increasing external concentration. Further, decreasing the temperature from 20ºC to 5ºC and increasing the salinity from 0‰ to 5‰ S reduced Zn and Cd uptake by a factor of two.</p><p>In <i>P. natans</i> the metals were not translocated within the plant, while in<i> E. canadensis </i>Cd moved between roots and shoots. Thus,<i> E. canadensis</i> as opposed to <i>P. natans</i> may increase the dispersion of metals from sediment via acropetal translocation. The low basipetal translocation implies that neither <i>E. canadensis</i> nor <i>P. natans</i> will directly mediate the immobilisation of metal to the sediment via translocation.</p><p>To conclude, emergent and terrestrial plant species seem to enhance metal stabilization in the soil/sediment. The submersed plants, when present, slightly increase the retention of metals via shoot accumulation.</p>

<p>An analysis of a specific application of anaerobic wastewater treatment at a pulp and board mill, Stora Enso Skoghall, was carried out. A literature study was done and effluent wastewater from CTMP pulp production was analyzed. The analysis consisted of a broad constituent analysis and an anaerobic treatment trial. Results from these test where used to calculate the treatment effectiveness and resulting energy potential at the mill.</p><p>The literature study and constituent analysis showed that toxicity of the water to be treated, due to wood extractives and sulphur content, was of concern. Detoxification chemicals targeting these constituents where used in the anaerobic treatment trial. The trial consisted of a two chamber upflow reactor and aerobic post treatment. The result of the trial is that the water of concern has about 50% anaerobically degradable content. A full scale implementation of anaerobic wastewater treatment would result in a methane production of 3,76 to 7,76 GWh/yr. An application of anaerobic wastewater treatment will also result in electricity savings, in aerated pond, and increase the capacity margin on current sludge handling techniques.</p>

<p>This thesis deals with the highly potent olfactory mucosa toxicant 2,6-dichlorophenyl methylsulphone (2,6-diClPh-MeSO₂) and its non-toxic 2,5-chlorinated isomer (2,5-diClPh-MeSO₂). In mice, both substances bind firmly in the olfactory mucosa and the olfactory bulb, which are important components of the sensory system. The 2,6-isomer induces olfactory mucosal necrosis with permanent loss of olfactory neuroepithelium and olfactory nerves. A major objective was to clarify the cause of this isomer-specific toxicity, and to identify which physicochemical characteristics determine the olfactory toxicity. The neurobehavioural toxicity of these substances was also examined.</p><p>The results revealed a rapid CYP-catalysed covalent binding of 2,6-diClPh-MeSO₂ in the rat olfactory mucosa, whereas the 2,5-dichlorinated isomer was not covalently bound. </p><p>Acute and chronic olfactory mucosal pathology were investigated and compared in rats and mice. Twenty-four hours after dosing to rats, 2,6-diClPh-MeSO₂ induced Bowman’s glands necrosis and sloughing of the olfactory epithelium similar to that previously reported in mice. At 3 weeks, however, there were dramatic differences in histological lesions. In mice, large parts of olfactory epithelium were replaced by respiratory-like epithelium. Large, bilateral, fibrous, cartilage and bone containing polyps occluding the lumen were confirmed. In rats, only minor patches of olfactory epithelium were replaced by a metaplastic atypical respiratory-like epithelium. 2,5-diClPh-MeSO₂ was non-toxic in rats as well as in mice.</p><p>In mice, 2,6-diClPh-MeSO₂ induced a dose-dependent and long-lasting ( ≥12 weeks) hyperactivity as well as long-lasting maze learning deficits. At 2 weeks hyperactivity and maze learning deficits were observed also in rats. Unexpectedly, 2,5-diClPh-MeSO₂ induced hyperactivity that lasted for two weeks. No effect on maze learning was observed with this isomer. No major differences between male and female rats or mice were found.</p><p>In conclusion, the results show that a CYP-catalysed formation and covalent binding of a reactive 2,6-diClPh-MeSO₂-metabolite in the Bowman’s glands precede the high olfactory mucosal toxicity in rodents. As determined by QSAR-modelling, a 2,6-dichlorinated benzene derivative with a large, polar, and strong electron withdrawing substituent in the primary position has the potential of being an olfactory mucosal toxicant. The observed 2,6-diClPh-MeSO₂-induced increase in motor activity, and maze learning deficits, were not correlated to the olfactory mucosal lesions. I propose that 2,6-diClPh-MeSO₂ causes a direct effect in the brain leading to neurobehaviuoral deficits. </p>

<p>Interaction between mercury and selenium has previously been observed both in man and in animals. The aim of this work was to study expressions of interaction between mercury and selenium in human K-562 cells. Inorganic and organic forms of mercury and selenium were used and cells were either pre-treated with selenium or simultaneously exposed to selenium and mercury. Concentrations of selenium and mercury chosen were indicated by a study of growth inhibition in the individual compounds: a low concentration of selenium and selenomethionine induced slight cell growth inhibition, while a high concentration resulted in a notable growth inhibition. Two mercury concentrations were chosen: one with minimal toxicity and another with high cell toxicity. In addition, uptake and retention patterns of selenomethionine and selenite differed in both selenocompounds.</p><p>All simultaneous treatments with 3.5 μM methylmercury produced a reduction in cellular mercury with increased selenium concentration. This was particularly obvious in selenite treatments. Growth curves from the simultaneous 3.5 μM methylmercury and selenite treatments indicated protection with increased selenite concentrations. In both exposure protocols, the 5 μM methylmercury treatments were toxic to the cells. </p><p>In both study protocols, cells exposed to selenite and mercuric chloride manifested increased cellular mercury uptake with increased selenium concentration. In all selenite and 35 μM mercuric chloride treatments, no inhibition of growth was observed, while the 50 μM mercuric chloride treatments were toxic to the cells. Selenite-dependent protection was achieved in both exposure protocols when considering the cellular uptake of mercury. With few exceptions, selenomethionine produced similar effects as selenite on mercuric chloride uptake and growth inhibition.</p>

During the past 30 years, numerous studies have focused on the toxicities of polycyclic aromatic hydrocarbons (PAH). Laboratory and field studies have helped elucidate the detrimental effects of these chemicals on growth, reproduction and immune response. Polycyclic aromatic hydrocarbons are in the priority list of chemicals to be studied by different governmental agencies and universities and understanding their mechanisms of action is the focus of the current research. The manuscripts presented in this dissertation are focused on the effects and mechanism of action of PAH on disease susceptibility. After a dietary exposure to PAH for up to 50 days (chapter II) and samplings after 3, 7, 14, 28 and 50 days, a number of biomarkers of PAH exposure were measured: Fluorescent aromatic compounds (FACs) in bile, ethoxyresorufin-o-deethylase (EROD) in liver microsomes, cytochrome P450 1A immunohistochemistry in liver and kidney and adduct formation in liver. Additionally markers of oxidative stress were measured: comet assay in blood, protein nitration in kidney and F2-isoprostanes in kidney. Oxidative stress was a probable factor in PAH induced responses in fish adapted to long-term PAH exposures and aryl hydrocarbon activation was not necessarily involved in this process. Disease challenge with Aeromonas salmonicida (chapter III) resulted in differences in mortalities that demonstrated that fish exposed to PAH were more susceptible to disease than fish not exposed to PAH. Determination of gene expression in head kidney of fish exposed and not exposed to PAH challenged with A. salmonicida using microarray and RT-PCR technologies 2, 4, 10 and 20 days after challenge (chapter IV), suggested that PAH exposure was associated with down regulation of interleukin 8, transport associated protein 1, NF-kB modulator, recombination activating gene and major histocompatibility complex II two days after challenge in fish exposed to PAH. The transcript levels were closer to control levels 20 days after challenge, this indicated a recovery from the effect of PAH exposure. / Graduation date: 2006

Identification of the unknown targets of drugs, investigative drugs and herbal ingredients is an important task in drug discovery. It can potentially help in several aspects including: (1) determination of unknown therapeutic mechanism of certain drugs and medicinal herbs, (2) prediction of drug toxicity and side effect, and (3) analysis of protein-mediated pharmacokinetic properties of drugs. Here, a computer-aided drug target search method and its validation studies are presented. / Singapore-MIT Alliance (SMA)

<p>&nbsp / </p> <p align="left"><font face="Times New Roman">Aspalathus linearis (A. linearis), </font><font face="Times New Roman">commonly known as Rooibos tea or Red bush tea and </font><i><font face="Times New Roman">amellia sinensis (C. sinensis) </font></i><font face="Times New Roman">or Black tea are beverages that are consumed throughout the</font><font face="Times New Roman">world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim</font> <font face="Times New Roman">of this study was to use <i>in vitro </i>assays to screen Rooibos and Black tea for endocrine</font> <font face="Times New Roman">modulation. </font><font face="Times New Roman">The immune modulating effects of Rooibos and Black tea were investigated using an <i>in vitro</i></font> <font face="Times New Roman">whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted</font> <font face="Times New Roman">higher levels of IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFN&gamma / </font><font face="Times New Roman">secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated</font> <font face="Times New Roman">WBC resulted in decreased IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>secretion compared to the DMSO treated</font> <font face="Times New Roman">stimulated WBC. </font><font face="Times New Roman">Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative </font><font face="Times New Roman">estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that </font><font face="Times New Roman">Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels </font><font face="Times New Roman">than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen</font> <font face="Times New Roman">dependant MCF-7 cell line was determined to further characterise the phytoestrogenic</font> <font face="Times New Roman">properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of</font> <font face="Times New Roman">MCF-7 proliferation. </font><font face="Times New Roman">This study shows that Rooibos tea and Black tea are beverages that can either stimulate or </font><font face="Times New Roman">suppress the immune system. Also, both teas contain significant levels of phytoestrogens as </font><font face="Times New Roman">determined by quantitative ELISAs. The current study confirms previous reports showing </font><font face="Times New Roman">inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend </font><font face="Times New Roman">related observations on the anti-carcinogenic potential of the two teas.</font></p>

Interaction between mercury and selenium has previously been observed both in man and in animals. The aim of this work was to study expressions of interaction between mercury and selenium in human K-562 cells. Inorganic and organic forms of mercury and selenium were used and cells were either pre-treated with selenium or simultaneously exposed to selenium and mercury. Concentrations of selenium and mercury chosen were indicated by a study of growth inhibition in the individual compounds: a low concentration of selenium and selenomethionine induced slight cell growth inhibition, while a high concentration resulted in a notable growth inhibition. Two mercury concentrations were chosen: one with minimal toxicity and another with high cell toxicity. In addition, uptake and retention patterns of selenomethionine and selenite differed in both selenocompounds. All simultaneous treatments with 3.5 μM methylmercury produced a reduction in cellular mercury with increased selenium concentration. This was particularly obvious in selenite treatments. Growth curves from the simultaneous 3.5 μM methylmercury and selenite treatments indicated protection with increased selenite concentrations. In both exposure protocols, the 5 μM methylmercury treatments were toxic to the cells. In both study protocols, cells exposed to selenite and mercuric chloride manifested increased cellular mercury uptake with increased selenium concentration. In all selenite and 35 μM mercuric chloride treatments, no inhibition of growth was observed, while the 50 μM mercuric chloride treatments were toxic to the cells. Selenite-dependent protection was achieved in both exposure protocols when considering the cellular uptake of mercury. With few exceptions, selenomethionine produced similar effects as selenite on mercuric chloride uptake and growth inhibition.