Bone discolouration of pig carcasses is a quality concern that has been observed in Ontario slaughter plants. The objectives of this study were to establish the prevalence of pig carcasses showing bone discolouration, its relationship with residues of tetracyclines in bones, and to investigate the use of tetracyclines in feeding programs for grower-finisher pigs as the main risk factor for discolouration. Abattoir data were examined to determine the extent of the problem and the prevalence of bone discolouration during 2006, 2008, 2009, and 2010 was found to be 0.13%, 0.22%, 0.26%, and 0.28%, respectively, indicating that the issue of bone discolouration was present at low levels over the entire period of the study. A controlled trial using feed, water, and injectable tetracycline products to investigate the effect of tetracyclines on residue and bone colour was conducted. Bones were assessed visually for signs of discolouration, and high performance liquid chromatography (HPLC) was used to measure the levels of tetracycline residues in the bones. Results from this trial demonstrated that discolouration could be produced with 660ppm of chlortetracycline (CTC) in feed for 12 weeks even when 33 days of withdrawal time was observed. It was also found that residues of tetracyclines can be present in bones in the absence of discolouration. A retrospective study was conducted to investigate tetracycline use in herds identified as having discoloured bones at slaughter. Positive shipments were associated with dosage and duration of CTC use as well as with length of withdrawal. In conclusion, discoloured bones of pig carcasses were identified at low levels in one large Ontario abattoir; however, further investigation is needed in order to determine the impact it may have on the swine industry. / Ontario Pork and the University of Guelph - Ontario Ministry of Agriculture (OMAFRA) Sustainable Production System Program

[Truncated abstract] Faba bean (Vicia Faba L.) ranks third worldwide in overall production among coolseason legume crops and is used as a main source of protein both for food and feed purposes in many parts of the world. Australia is a major exporter of faba beans and the price received depends on the quality of the seed especially colour of the seed coat. Consumers don?t like faba beans that are dark coloured or that have blemishes on the seed coat. Environmental staining and storage discolouration deteriorate seed colour causing substantial economic losses to growers and grain handlers. To investigate the influence of environmental conditions, especially during pod/seed development and maturity, on the degree of environmental staining, field trials were conducted using four faba bean varieties (Fiord, Fiesta, Ascot and Cairo) in a range of environmental conditions under the Mediterranean-type climate of south western Australian grain belt. Although a majority of seeds had good colour but 3-25% were stained up to an unacceptable level across the trials and this varied with location and variety. Seeds formed later in plant development (located on the upper nodes of the plant) were more stained than seeds formed earlier (located on the lower nodes). This may be due to end of season environmental factors, such as high temperature and light intensity, and water and nutrient stress. Similarly seeds formed on small and weak plants, which may have developed under stressful conditions, had more staining than seeds formed on normal sized and healthy plants. Genotypic variation was also evident with Fiord showing greater staining than Ascot, Fiesta and Cairo. The cause of environmental staining appears to be complex but was associated with phenolic contents. Storage discolouration was influenced by a number of factors including temperature, seed moisture content, light and storage period and these were critical in determining storage life. ... Faba bean hardness, examined by the hard-to-cook test, also increased with increased storage temperature. There was a high negative correlation (r2 = 0.98) between storage temperature and cooking ability of faba bean. There was a three-fold increase in lignin content of faba bean stored at 50°C compared to those stored at 5°C and it was correlated with bean hardness (r2 = 0.98). Reduction in free phenolics was negatively correlated (r2 = 0.75) with bean hardness. The environmental staining in faba bean can be minimized with correct choice of varieties, robust agronomic practices to establish and maintain healthy plants and the use of mechanical graders and colour sorters. For minimizing storage discolouration faba beans must be dehydrated to ≤12% seed moisture content and stored in insulated bins (silos) or at least bins painted white and constructed under trees shades. In addition occasional flushing with N2 will further help reduce the colour darkening. The above approaches will improve quality, market opportunities, price and hence profitability of faba bean in the farming systems.

Seedling blight of maize has significantly influenced field crop stands and seedling vigour over various localities and seasons. The extent of the problem is influenced by a number of factors which includes soil temperature (generally below 13 °C), waterlogged soils, inadequate fertilization, herbicide damage and fungal pathogens. The fungi generally causing seedling damping off are often involved in a complex and succession over time varying in importance depending on the field circumstances at a given time. These generally include the Pythium spp., Rhizoctonia spp. and various Fusarium spp. These have been recorded in a number of studies conducted by local researchers in the late 1980’s and early 1990’s on sorghum but to a lesser degree on maize. Uncertainty regarding the status of the etiology of maize seedling blights as maize production practices have changed dramatically in the last 10 years with increased plant populations, reduced tillage, increased crop rotation options and new short season maize hybrids. It is therefore essential to determine the present status of seedling blights in South Africa to confirm the necessity of fungicide seed treatments to ensure adequate plant densities and seedling vigour. Cob and tassel smut caused by Sphacelotheca reiliana is a disease of maize that was a problem in the 1970’s. Due to improved fertilisation, fungicide seed treatments and hybrid resistance this disease was reduced to such levels that the disease was only found to occur on research farms where seedlings were inoculated. Since 2007, the disease was reported to reach epidemic proportions on the heavy clay soils in the Standerton area. This disease has since spread over the last seven seasons to a range including northern KwaZulu/Natal, namely as far as Underberg/Swartberg, the Witbank, Ermelo, Middelburg and Delmas area in Mpumalanga and to Harrismith in the eastern Free State maize production area. This may be due to susceptible hybrids coming onto the local market or the inability of traditional fungicide seed treatments to contain infection. New and unregistered seed treatments available will be tested for their ability to control cob and tassel smut in two fields over two seasons. The aims of this dissertation were to determine the extent of the seedling blight problem in commercial fields throughout the maize industry. To determine the efficacy of fungicide seed treatments for the control of maize seedling blights using both field and greenhouse studies, and to determine the efficacy of fungicide seed treatments for the control of cob and tassel smut of maize in field trials. A total of 101 localities were sampled throughout the maize producing region of South Africa with root discolouration varying from 0 to 90 % root discolouration. Seventy different fungal species were isolated from the maize seedlings roots which include species such as Aspergillus, Clonostachus, Fusarium, Trichoderma and Penicillium. The most commonly isolated fungi which included Aspergillus niger, Fusarium solani, Fusarium verticillioides and Fusarium oxysporum were evaluated in glasshouse studies to determine their pathogenicity. Pathogenicity differed between isolates of the same fungal species, which were collected from different geographical regions, in the glasshouse studies. Field trials for seedling blight disease showed significant differences between the localities (P < 0.001) the trials were planted at, and between seed treatments. Significant season (P < 0.001) and locality (P < 0.05) differences were also found for cob and tassel smut trials planted at Potchefstroom, North-West province and Greytown, KwaZulu/Natal Province respectively. Fungicide seed treatments also showed significant differences for cob and tassel smut regarding plants infected (P < 0.001) and yield loss (P < 0.05). Overall seed treatments can be seen as an effective controlling agent for the control of seed- and soil-borne fungi on maize. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Seedling blight of maize has significantly influenced field crop stands and seedling vigour over various localities and seasons. The extent of the problem is influenced by a number of factors which includes soil temperature (generally below 13 °C), waterlogged soils, inadequate fertilization, herbicide damage and fungal pathogens. The fungi generally causing seedling damping off are often involved in a complex and succession over time varying in importance depending on the field circumstances at a given time. These generally include the Pythium spp., Rhizoctonia spp. and various Fusarium spp. These have been recorded in a number of studies conducted by local researchers in the late 1980’s and early 1990’s on sorghum but to a lesser degree on maize. Uncertainty regarding the status of the etiology of maize seedling blights as maize production practices have changed dramatically in the last 10 years with increased plant populations, reduced tillage, increased crop rotation options and new short season maize hybrids. It is therefore essential to determine the present status of seedling blights in South Africa to confirm the necessity of fungicide seed treatments to ensure adequate plant densities and seedling vigour. Cob and tassel smut caused by Sphacelotheca reiliana is a disease of maize that was a problem in the 1970’s. Due to improved fertilisation, fungicide seed treatments and hybrid resistance this disease was reduced to such levels that the disease was only found to occur on research farms where seedlings were inoculated. Since 2007, the disease was reported to reach epidemic proportions on the heavy clay soils in the Standerton area. This disease has since spread over the last seven seasons to a range including northern KwaZulu/Natal, namely as far as Underberg/Swartberg, the Witbank, Ermelo, Middelburg and Delmas area in Mpumalanga and to Harrismith in the eastern Free State maize production area. This may be due to susceptible hybrids coming onto the local market or the inability of traditional fungicide seed treatments to contain infection. New and unregistered seed treatments available will be tested for their ability to control cob and tassel smut in two fields over two seasons. The aims of this dissertation were to determine the extent of the seedling blight problem in commercial fields throughout the maize industry. To determine the efficacy of fungicide seed treatments for the control of maize seedling blights using both field and greenhouse studies, and to determine the efficacy of fungicide seed treatments for the control of cob and tassel smut of maize in field trials. A total of 101 localities were sampled throughout the maize producing region of South Africa with root discolouration varying from 0 to 90 % root discolouration. Seventy different fungal species were isolated from the maize seedlings roots which include species such as Aspergillus, Clonostachus, Fusarium, Trichoderma and Penicillium. The most commonly isolated fungi which included Aspergillus niger, Fusarium solani, Fusarium verticillioides and Fusarium oxysporum were evaluated in glasshouse studies to determine their pathogenicity. Pathogenicity differed between isolates of the same fungal species, which were collected from different geographical regions, in the glasshouse studies. Field trials for seedling blight disease showed significant differences between the localities (P < 0.001) the trials were planted at, and between seed treatments. Significant season (P < 0.001) and locality (P < 0.05) differences were also found for cob and tassel smut trials planted at Potchefstroom, North-West province and Greytown, KwaZulu/Natal Province respectively. Fungicide seed treatments also showed significant differences for cob and tassel smut regarding plants infected (P < 0.001) and yield loss (P < 0.05). Overall seed treatments can be seen as an effective controlling agent for the control of seed- and soil-borne fungi on maize. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

In previous studies silicon has been associated with reduced disease severity and incidence, the enhanced accumulation of phenolic compounds and lignin, and with changes in the defence-related enzyme activity and transcript abundance of defence and stress related genes. All of these aspects of plant defence were considered in this study on cotton infected with Fusarium oxysporum f. sp. vasinfectum (Fov), and the results obtained have greatly enhanced our understanding of the effects of silicon on this interaction. In all experiments conducted, defence responses were only significantly enhanced by silicon treatment following inoculation with Fov, strongly suggesting that silicon can prime defence responses in cotton infected with Fov. Sicot F-1 was the cultivar most resistant to Fov infection at the commencement of this research, whilst Sicot 189 was considered to have moderate resistance to the pathogen. Vascular discolouration was significantly reduced in the more resistant cultivar, Sicot F-1 following treatment with potassium silicate, compared to mock inoculated plants and inoculated plants treated with potassium sulphate or calcium sulphate. No significant differences between treatments were observed in the moderately resistant cultivar, Sicot 189, though further trials may need to be conducted to confirm this result. In both cultivars, silicon content was significantly greater in plants which had been treated regularly with liquid potassium silicate, rather than with calcium silicate powder. Histological investigation of cotton infected with Fov, with and without silicon treatment, was conducted to ascertain the effects of this element on the accumulation of fungitoxic phenolic compounds, cell ultrastructural changes and fungal infection structures. Fov proliferated through the cortex and stele of plants from both the resistant (Sicot F-1), and moderately resistant (Sicot 189) cultivars, regardless of silicon treatment. However, defences were more rapidly and intensely induced in endodermal and vascular regions of inoculated, potassium silicate treated Sicot F-1 plants. Significantly more phenolic compounds were present at seven days post infection (dpi) in root extracts of inoculated, potassium silicate treated Sicot F-1 plants. Phenolic compounds were not significantly increased in inoculated, potassium silicate treated root extracts of Sicot 189 plants at three or seven dpi. Lignin assays demonstrated that the dry weight percentage of lignin in root material from inoculated, potassium silicate treated Sicot F-1 plants was significantly higher than that of extracts from inoculated plants not receiving silicon treatment at three dpi. This trend was also observed at seven dpi; however lignin content was not significantly different in this case. Percentage lignin content in the roots of Sicot 189 plants was not significantly different between inoculated potassium silicate treated plants and those not treated with silicon. Histological alterations were not observed in mock inoculated water or potassium silicate treated plants, nor were any significant increases in phenolic compounds or lignin accumulation detected in control treatments not inoculated with the pathogen. The expression of several defence related genes was assessed with quantitative reverse transcriptase real-time polymerase chain reaction. The results obtained verify that potassium silicate can enhance defence responses in Sicot 189 and Sicot F-1 plants inoculated with Fov, with silicon having a more pronounced effect on the more resistant cultivar, Sicot F-1. Genes upregulated at three and four dpi in potassium silicate treated, Fov inoculated Sicot F-1 plants included peroxidase, cadinene synthase and polygalacturonase inhibiting protein (PGIP), with peroxidase associated with phenol oxidation and lignification and cadinene synthase with phytoalexin biosynthesis. Osmotin-like protein and chitinase class I were consistently upregulated in potassium silicate treated, inoculated Sicot 189 plants; both genes coding for pathogenesis related (PR) proteins, with chitinase also classified as an antifungal protein. In both cultivars, silicon treatment without Fov inoculation did not result in the significant up-regulation of any of the defence genes assessed, providing further evidence for the role of silicon in priming in this interaction. The activities of three defence related enzymes, peroxidase, chitinase and β-1, 3- glucanase was assessed in root and shoot material by colourimetric assays. Regular application of potassium silicate significantly increased the activity of peroxidase in root extracts from the highly resistant cultivar Sicot F-1, at three, four and seven dpi with Fov, and in root extracts from the moderately resistant Sicot 189 at three and four dpi. Significant increases in chitinase activity in inoculated, silicon treated Sicot 189 plants were observed in root extracts at three dpi, and in shoot extracts at four dpi. Soluble potassium silicate treatment resulted in significant increases in β-1, 3- glucanase activity in Sicot 189 root extracts at four dpi. Few significant differences between treatments in terms of chitinase and β-1, 3- glucanase activity were detected in Sicot F-1 plants, though higher levels of each of these enzymes were present in root and shoot extracts from this cultivar. In this study the effects of acibenzolar-S-methyl, applied in the form of Bion®, on defence gene expression and enzyme activity in cotton infected with Fov were more pronounced in plants cultivated from treated seed, rather than in plants treated via foliar spray; a finding which is particularly relevant to the industry presently. Significant up-regulation of chitinase class I, peroxidase, and β-1, 3-glucanase transcripts and enzyme activities occurred in the Bion® seed soak treatment with Fov inoculation compared to all other treatments. It was possible to compare the actions of silicon with those of Bion® in this study. Bion® primed defence responses in cotton infected with Fov, in a manner similar to that observed in silicon treated cotton. The use of silicon and Bion® treatments, both alone and in combination as part of integrated disease management programmes, may potentially contribute to increased protection against this pathogen in Australian cotton fields in the future.

As lacases (EC 1.10.3.2) são fenol-oxidases associadas à habilidade de degradar a lignina e outros compostos recalcitrantes, como xenobióticos e vários tipos de corantes sintéticos. Lacases catalisam a oxidação de vários compostos aromáticos com concomitante redução do oxigênio a água. Neste trabalho são apresentados os resultados de imobilização do extrato de lacases de Pleurotus sajor-caju PS2001 em filmes poliméricos de poliamida 6,6 (PA) e polissulfona (PSU), utilizando glutaraldeído como agente de ligação. A solução enzimática de lacases foi obtida em meio sólido contendo serragem de Pinus spp cultivado com P. sajor-caju. As proteínas da solução enzimática foram imobilizadas em filmes de PA e PSU. O processo de imobilização foi estudado quanto ao pH ótimo, sendo os filmes caracterizados quanto à quantidade de proteínas imobilizadas e atividade de lacases. As membranas de PA apresentaram maior atividade de lacases quando comparadas com as de PSU. Observou-se uma redução do pH ótimo para atividade de lacases imobilizadas, utilizando-se o tampão acetato e um aumento em tampão Mcllvaine. A maior atividade de lacases foi obtida após 6 h de imobilização, em reação a 30°C, com agitação constante, tanto para os filmes de PA quanto para os de PSU. Verificou-se descoloração de aproximadamente 90% da solução 25 mg/L do corante Reactive Blue 220, após 24 horas de reação, utilizando membranas de PA com a enzima imobilizada. Aproximadamente 50% da descoloração obtida deve-se a adsorção do corante pela membrana. Resultados semelhantes foram obtidos com a utilização do corante Remazol Brilliant Blue R (RBBR), com adição de Reactive Blue 220. Não foi observada descoloração sem adição do Reactive Blue, sugerindo uma ação semelhante a um mediador, proporcionando a descoloração do RBBR. Apesar de serem observadas atividades de lacases imobilizadas nas membranas de PSU, utilizando-se ABTS como substrato, não foi observada descoloração dos corantes analisados. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-14T18:02:47Z No. of bitstreams: 1 Dissertacao Katia Rasera.pdf: 933755 bytes, checksum: fadf6b200d674217ac06cf5b50743776 (MD5) / Made available in DSpace on 2014-05-14T18:02:47Z (GMT). No. of bitstreams: 1 Dissertacao Katia Rasera.pdf: 933755 bytes, checksum: fadf6b200d674217ac06cf5b50743776 (MD5) / Laccases (EC 1.10.3.2) are phenol-oxidase enzymes associated to the degradation of lignin and a wide variety of recalcitrant compounds, such as xenobiotics and different types of dyes. Laccases catalyze the oxidation of various aromatic compounds with the concomitant reduction of oxygen to water. In this work, the results of immobilization of Pleurotus sajor-caju PS 2001 laccases in polyamide 6,6 (PA) and polysulfone (PSU) films, using glutaraldehyde as linking agent, are presented. The enzymatic solution containing laccases was obtained from solid medium with Pinus spp sawdust cultivated with P. sajor-caju. The proteins present in this solution were immobilized in PA and PSU films The immobilization process was studied with respect to the optimum pH, and the films were evaluated to determine the protein content and laccase activity. PA membranes showed higher laccase activity than PSU ones. With immobilized enzymes, a reduction of the optimum pH for laccase activity was observed, using acetate buffer and a increase using Mcllvaine buffer. The higher laccase activity was achieved after 6 h of immobilization, at a reaction temperature of 30°C, under agitation, for both PA and PSU films. Discolouration of approximately 90% of solution 25 mg.L-1 of the dye Reactive Blue 220 was verified, after 24 hours of reaction, using membranes of PA with the immobilized enzyme. Approximately 50% of the discolouration would be attributed from the adsortion process of the dye for the PA membrane. Similar results had been gotten with the use of the dye Remazol Brilliant Blue R (RBBR), with addition of Reactive Blue 220. Discolouration without addition of the Reactive Blue was not observed, suggesting a similar action to a mediator, providing the discolouration of the RBBR. Although to be observed immobilized activities of lacases in the membranes of PSU, using ABTS as substratum, discolouration of the analyzed corantes was not observed.

As lacases (EC 1.10.3.2) são fenol-oxidases associadas à habilidade de degradar a lignina e outros compostos recalcitrantes, como xenobióticos e vários tipos de corantes sintéticos. Lacases catalisam a oxidação de vários compostos aromáticos com concomitante redução do oxigênio a água. Neste trabalho são apresentados os resultados de imobilização do extrato de lacases de Pleurotus sajor-caju PS2001 em filmes poliméricos de poliamida 6,6 (PA) e polissulfona (PSU), utilizando glutaraldeído como agente de ligação. A solução enzimática de lacases foi obtida em meio sólido contendo serragem de Pinus spp cultivado com P. sajor-caju. As proteínas da solução enzimática foram imobilizadas em filmes de PA e PSU. O processo de imobilização foi estudado quanto ao pH ótimo, sendo os filmes caracterizados quanto à quantidade de proteínas imobilizadas e atividade de lacases. As membranas de PA apresentaram maior atividade de lacases quando comparadas com as de PSU. Observou-se uma redução do pH ótimo para atividade de lacases imobilizadas, utilizando-se o tampão acetato e um aumento em tampão Mcllvaine. A maior atividade de lacases foi obtida após 6 h de imobilização, em reação a 30°C, com agitação constante, tanto para os filmes de PA quanto para os de PSU. Verificou-se descoloração de aproximadamente 90% da solução 25 mg/L do corante Reactive Blue 220, após 24 horas de reação, utilizando membranas de PA com a enzima imobilizada. Aproximadamente 50% da descoloração obtida deve-se a adsorção do corante pela membrana. Resultados semelhantes foram obtidos com a utilização do corante Remazol Brilliant Blue R (RBBR), com adição de Reactive Blue 220. Não foi observada descoloração sem adição do Reactive Blue, sugerindo uma ação semelhante a um mediador, proporcionando a descoloração do RBBR. Apesar de serem observadas atividades de lacases imobilizadas nas membranas de PSU, utilizando-se ABTS como substrato, não foi observada descoloração dos corantes analisados. / Laccases (EC 1.10.3.2) are phenol-oxidase enzymes associated to the degradation of lignin and a wide variety of recalcitrant compounds, such as xenobiotics and different types of dyes. Laccases catalyze the oxidation of various aromatic compounds with the concomitant reduction of oxygen to water. In this work, the results of immobilization of Pleurotus sajor-caju PS 2001 laccases in polyamide 6,6 (PA) and polysulfone (PSU) films, using glutaraldehyde as linking agent, are presented. The enzymatic solution containing laccases was obtained from solid medium with Pinus spp sawdust cultivated with P. sajor-caju. The proteins present in this solution were immobilized in PA and PSU films The immobilization process was studied with respect to the optimum pH, and the films were evaluated to determine the protein content and laccase activity. PA membranes showed higher laccase activity than PSU ones. With immobilized enzymes, a reduction of the optimum pH for laccase activity was observed, using acetate buffer and a increase using Mcllvaine buffer. The higher laccase activity was achieved after 6 h of immobilization, at a reaction temperature of 30°C, under agitation, for both PA and PSU films. Discolouration of approximately 90% of solution 25 mg.L-1 of the dye Reactive Blue 220 was verified, after 24 hours of reaction, using membranes of PA with the immobilized enzyme. Approximately 50% of the discolouration would be attributed from the adsortion process of the dye for the PA membrane. Similar results had been gotten with the use of the dye Remazol Brilliant Blue R (RBBR), with addition of Reactive Blue 220. Discolouration without addition of the Reactive Blue was not observed, suggesting a similar action to a mediator, providing the discolouration of the RBBR. Although to be observed immobilized activities of lacases in the membranes of PSU, using ABTS as substratum, discolouration of the analyzed corantes was not observed.