A terapia antiangiogênica surgiu como uma alternativa promissora para o tratamento do câncer. No entanto, evidências recentes mostram que as células endoteliais isoladas diretamente de um tumor maligno são mais resistentes a diferentes drogas do que as células endoteliais presentes no mesmo tecido normal. Essas diferenças podem ser atribuídas em parte à adaptação das células endoteliais ao microambiente tumoral. Uma característica singular do microambiente tumoral é a consistente acidificação do meio extracelular, cujos efeitos nas células endoteliais não são conhecidos. Acidez extracelular pode alterar múltiplas funções biológicas, causar estresse do retículo endoplasmático (RE) e ativação da Unfolded Protein Response (UPR). Células endoteliais humanas primárias de derme (HDMEC) cultivadas em pH 6.4, ajustado tanto com ácido lático tanto com ácido clorídrico, apresentaram aumento da expressão de proteínas relacionadas à UPR, como GRP78, ATF4, elf2α fosforilada e aumento na clivagem do mRNA de XBP1. Nessas condições massiva morte celular ocorreu após 48 horas. Em contrapartida, quando as células endoteliais eram expostas à acidez crônica não-letal com pH 7.0 durante sete dias, essas foram capazes de se adaptar coincidentemente com um aumento da expressão da proteína GRP78 Após sete dias sob pH 7.0, as células HDMEC apresentaram maior resistência à morte celular quando tratadas com as drogas Etoposide, Adriamicina e Sunitinib em doses que variavam entre 0.0025μM a 100μM. O silenciamento do gene GRP78 com ShRNA reverteu esse fenótipo resistente. Para determinar os níveis de UPR in vivo utilizou-se captura por microdissecção à laser de células endoteliais em lâminas histológicas de 14 carcinomas espinocelulares bucais. Observou-se um aumento significativo dos níveis de mRNA de GRP78, ATF4 e CHOP em células endoteliais dos tumores quando comparadas a células endoteliais primárias (HDMEC). Além do mais, células endoteliais tumorais apresentaram intensa imunomarcação para GRP78 comparativamente a células endoteliais de mucosa bucal normal. A acidez, uma importante fonte de estresse no microambiente tumoral, pode ativar uma UPR adaptativa em células endoteliais. Aumento da expressão de GRP78 em células endoteliais é associado com maior resistência a drogas quimioterápicas. Os resultados sugerem que a resistência mediada pela UPR pode contribuir com o insucesso terapêutico na resposta a drogas antitumorais. / Antiangiogenic therapy has emerged as a promising alternative for cancer treatment. However, growing evidence has shown that endothelial cells isolated directly from malignant tumors are more resistant to different drugs than endothelial cells from normal tissues. These differences may due to the adaptation of endothelial cells to the tumor microenvironment. A unique feature of tumor microenvironment is the consistent acidification of the extracellular environment, whose effects on endothelial cells are not known. Extracellular acidity can alter multiple biological functions, including endoplasmic reticulum stress and activation of the Unfolded Protein Response (UPR). Primary human dermal microvascular endothelial cells (HDMEC) cultured at medium pH 6.4, adjusted with either lactic acid or either hydrochloric acid, showed strong up-regulation of the UPR-related proteins: GRP78, ATF4, phospho-elf2α and increased XBP1 mRNA splicing. However massive cell death occurred after 48 hours. In contrast, when endothelial cells were exposed to chronic nonlethal acidic stress at pH 7.0 for up to seven days, cells were able to adapt, coincidental with a marked increase in GRP78 protein expression. After 7 days at pH 7.0, HDMEC cells showed increased resistance to cell death when exposed to Etoposide, Adriamycin and Sunitinib at doses ranging from 0.0025μM to 100μM. Knockdown of GRP78 by shRNA reversed the resistance phenotype. To determine the levels of UPR in vivo, laser capture microdissection of endothelial cells from oral squamous cell carcinomas biopsies was done. There is a significant increase in mRNA levels of GRP78, ATF4 and CHOP on endothelial cells of tumors compared to untreated primary endothelial cells (HDMEC). Moreover, tumor 16 endothelial cells showed strong GRP78 immunostaining compared to endothelial cells from normal oral mucosa. Low pH, an important source of cellular stress in the tumor microenvironment, can activate an adaptive UPR response in endothelial cells. Increased expression of GRP78 in endothelial cells is associated with chemoresistance. The results suggest that UPR-mediated resistance may contribute to therapeutic failures in response to anticancer drugs.

Pasture plants already adapted to acidic soil conditions are required as part of an integrated approach (with lime amelioration) to managing acid soils on the Tablelands of New South Wales, Australia. The objective of this thesis is to evaluate the usefulness of Austrodanthonia species for this purpose. The material evaluated in this study was collected during a previous survey of the distribution of Austrodanthonia on the Central, Southern and Monaro Tablelands of New South Wales. It was hypothesised that the genus Austrodanthonia has a wide range of tolerance to acid soils. A series of experiments that provided information on the growth and physiology of Austrodanthonia in relation to soil acidity, with a view to the identification and eventual domestication of the most promising plant material have been conducted through pot, hydroponics and field investigations. Firstly, soils were acidified or limed to obtain a range of soil pH and Al concentrations. This experiment showed that adding aluminium sulfate and calcium carbonate followed by washing excess salts with water is a simple, rapid and convenient method for adjusting soil pH for pot experiments. The pH of the amended soils remained relatively unchanged eight months after treatment. The experimental set-up also resulted in a wide range of soluble Al (2-52 mg/kg) across the soils. The relative Al-tolerance of 183 accessions from 15 Austrodanthonia species was tested in a pot experiment using a range of soil pH. Emergence, survival and growth of all accessions were drastically reduced by high soil acidity (pH 3.9, P < 0.001). About 11% of plants emerged at pH 3.9, whereas at pH 4.4 and 5.3, ~72% of plants emerged. Accessions exhibited large variation within and between species in their tolerance to soil acidity. From the species/accessions tested, 49 accessions from eight species were selected for further study (on the basis of being more acid tolerant). Hydroponic experiments conducted in the glasshouse evaluated: (i) formulation of nutrient solution with a stable pH, (ii) effectiveness of the formulation using tap water and deionised water and (iii) estimation of free ion activities of Al and Mn in the nutrient solution and their effects on Austrodanthonia growth. These experiments showed that a NO3-N/NH4-N ratio of 9:4 is the most appropriate ratio to obtain a stable pH 4.0 without affecting plant growth; that there was little difference between tap water and deionised water on the ionic effects of Al and Mn, and plant-size did not play a role on accession survival and that accessions of Austrodanthonia could grow well within a wide range of pH (3.5-5.5), Al (50-250 �M) and Mn (100-2000 �M). Growth of Austrodanthonia accessions declined under high acidity (pH < 3.5) and Al (300 �M), but tolerated high concentrations of Mn (2000 �M). Root-tips stained with hematoxylin grouped accessions in a similar way to the pot and hydroponic experiments for most of the accessions tested. The intensity of root staining with hematoxylin and the differential distribution of Al in the shoots and roots provided an indication that different tolerance mechanisms may be involved with Austrodanthonia accessions. It appears that both exclusion and internal mechanisms may operate for Al- and Mn-tolerance. A field experiment was conducted at Carcoar (33037�S, 149013�E, elevation 800 m) using gradients in soil pH and Al available on-site to grow selected accessions of Austrodanthonia. The accessions exhibited a range of responses to soil acidity. The accession responses to acidity from the pot and hydroponic experiments were similar to those obtained in the field, especially where Al was present as a low Al-challenge. Overall, this study shows that Austrodanthonia exhibits a wide range of acid tolerance between species and accessions within species. Among the species tested, A. duttoniana and A. fulva appeared to have the greatest commercial potential, because of their productivity and acid tolerance. The variability that exists in the accessions may be exploitable in breeding and selection programs for improved cultivars.

Electrical Impedance Spectroscopy (EIS) is a relatively new method applied to food quality assessment. EIS allows relatively inexpensive assessment, is fast, easy to operate and non-invasive. It has been adopted for investigation of fundamental electrical properties of plant tissues. Although the applications of EIS for food quality determination have been reported previously, the analytical relationships between electrical impedance properties and quality criteria have not yet been fully developed. Further exploration is thus important in acquiring more data on electrical impedance characteristics of fruits and vegetables and researching new approaches for determination of their quality. This dissertation aims to investigate the electrical impedance properties of fruits and vegetables, and explore the relationship between impedance and quality criteria. In particular, the present dissertation outlines experimental research conducted on relationships between impedance properties and fruit tastes as well as the impedance changes observed during ripening process. Impedance measurement to monitor moisture content changes in the progress of drying is also included in this research. In summary, the impedance properties have merits in fruits and vegetables quality assessment. The current used subjective visual inspection and assessment could be replaced by the EIS based approach as it is a more precise measurement of food quality. Further study is required to give this method practical value.

The cycling of biogenic volatile sulfur compounds (VSCs) within marine and terrestrial ecosystems has been shown to play an integral role in atmospheric chemistry; by influencing global climate change through the creation of cloud condensation nuclei and controlling acid-base chemistry; as well as influencing sediment chemistry including the interactions with trace metals, particularly regarding iron sulfide formation. Despite this, the examination of VSCs within Australian coastal acid sulfate soils (ASS) is an unexplored area of research. As ASS in Australia occupy an area in excess of 9 M ha, there is a clear need for a greater understanding of the cycling of these compounds within such systems. This thesis looks at the concentrations of several VSCs within agricultural and undisturbed ASS on the east coast of Australia. Initial measurements of sulfur dioxide (SO2) were made using passive diffusion samplers, which were followed by two detailed field-based studies looking at the concentrations and fluxes of both SO2 and hydrogen sulfide (H2S) using flux-gradient micrometeorological techniques. These novel results indicated that this agricultural ASS was a substantial source of atmospheric H2S (0.036-0.056 gSm-2yr-1), and SO2 (0.095-0.31 gSm-2yr-1), with flux values equating to many other salt- and freshwater marshes and swamps. The flux data also suggested that the ASS could be a continual source of H2S which is photo-oxidised during the daytime to SO2. Measurements of both compounds showed separate, inverse correlations to temperature and moisture meteorological parameters indicating possible contributing and / or causal release factors. Further identification of these and other VSCs within ASS samplers was undertaken in the laboratory using gas chromatography in combination with solid-phase microextraction. Although SO2 and H2S were not discovered within the headspace samples, two other VSCs important in atmospheric sulfur cycling and trace metal geochemistry were quantified; dimethylsulfide (DMS; &gt 300??g/L) and ethanethiol (ESH &gt 4??g/L). The measurements of H2S, DMS and ESH are the first quantifications with Australian ASS, and they may be important for refining regional or local atmospheric sulfur budgets, as well as interpreting previous SO2 emissions from ASS. Ultimately this thesis further enhances our understanding of the cycling of VSCs within acid sulfate systems.

A novel non-destructive method of grape berry analysis is presented that uses reflected light to predict berry composition. The reflectance spectrum was collected using a diode array spectrometer (350 to 850 nm) over the 2009 and 2010 growing seasons. Partial least squares regression (PLS) and support vector machine regression (SVMR) generated calibrations between reflected light and composition for five berry components, total soluble solids (°Brix), titratable acidity (TA), pH, total phenols, and anthocyanins. Standard methods of analysis for the components were employed and characterized for error. Decomposition of the reflectance data was performed by principal component analysis (PCA) and independent component analysis (ICA). Regression models were constructed using 10x10 fold cross validated PLS and SVM models subject to smoothing, differentiation, and normalization pretreatments. All generated models were validated on the alternate season using two model selection strategies: minimum root mean squared error of prediction (RMSEP), and the "oneSE" heuristic. PCA/ICA decomposition demonstrated consistent features in the long VIS wavelengths and NIR region. The features are consistent across seasons. 2009 was generally more variable, possibly due to cold weather affects. RMSEP and R2 statistics of models indicate that PLS °Brix, pH, and TA models are well predicted for 2009 and 2010. SVM was marginally better. The R2 values of the PLS °Brix, pH, and TA models for 2009 and 2010 respectively were: 0.84, 0.58, 0.56 and: 0.89, 0.81, 0.58. 2010 °Brix models were suitable for rough screening. Optimal pretreatments were SG smoothing and relative normalization. Anthocyanins were well predicted in 2009, R2 0.65, but not in 2010, R2 0.15. Phenols were not well predicted in either year, R2 0.15-0.25. Validation demonstrated that °Brix, pH, and TA models from 2009 transferred to 2010 with fair results, R2 0.70, 0.72, 0.31. Models generated using 2010 reflectance data did not generate models that could predict 2009 data. It is hypothesized that weather events present in 2009 and not in 2010 allowed for a forward calibration transfer, and prevented the reverse calibration transfer. Heuristic selection was superior to minimum RMSEP for transfer, indicating some overfitting in the minimum RMSEP models. The results are demonstrative of a reflectance-composition relationship in the VIS-NIR region for °Brix, pH, and TA requiring additional study and development of further calibrations.

A series of pot trials were undertaken to test the growth of indigenous grasses (Themeda triandra and Cynodon dactylon) on mine capping soil, treated with various soil ameliorants. The capping soils were obtained from open cast coal mines (Optimum Mine and Syferfontein Mine) in the Mpumalanga Highveld, south of Witbank. However, because mine soil was not available at the commencement of the project, the initial pot trial used soil from the Umlazi Landfill in Durban. The trials were the Umlazi Landfill Trial, Microbe Trial, Legume Trial and Fly Ash Trial. For the Umlazi Landfill Trial, landfill top and subsoil was used along with fertilizer, sewage sludge, K-humate, lime and microbes. The soil ameliorant treatments for the Microbe trial were Trichoderma harzianum (Eco'T), Bacillus subtilis Strain 69 (B69) and Bacillus subtilis Strain 77 (B77), for the Legume Trial, Medicago sativa, phosphorus and/or potassium were applied. For the Fly Ash Trial, lime and fly ash were introduced. From the Landfill trial it was shown that fertilizer and sewage sludge significantly increased the above ground, below ground and total biomass of T. triandra, further, there were no significant treatment differences between fertilizer and sludge. The lime treatment for this trial, surprisingly, significantly reduced below ground biomass but the application of microbes (B69 and BcoT) alleviated this negative effect. However, in the Microbe Trial the microbes (BcoT, B69 and B77) had a negative or no effect on the biomass of T. triandra and C. dactylon. In the Legume Trial it was shown that the above ground biomass of T. triandra was significantly reduced when grown with M. sativa. The Fly Ash Trial revealed that the lime and fly ash treatments had no effect on the biomass of M. sativa and T. triandra, and they did not maintain a reduction in soil acidity. The results therefore indicated that either organic fertilizer or sewage sludge could be used to significantly improve the growth of T. triandra. It was also suggested that lime not be applied to soils with an acid saturation of approximately 1%, as this could retard plant growth. The application of microbes and the growth of a legume with grass, although both have been recorded to have beneficial effects in aiding plant growth, in the short-term however, the application of T. harzianum, B. subtilis Strain 69 and 77 applied to the soil while growing T.triandra and C. dactylon and the growth of M. sativa with T. triandra is not recommended. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

The cycling of biogenic volatile sulfur compounds (VSCs) within marine and terrestrial ecosystems has been shown to play an integral role in atmospheric chemistry; by influencing global climate change through the creation of cloud condensation nuclei and controlling acid-base chemistry; as well as influencing sediment chemistry including the interactions with trace metals, particularly regarding iron sulfide formation. Despite this, the examination of VSCs within Australian coastal acid sulfate soils (ASS) is an unexplored area of research. As ASS in Australia occupy an area in excess of 9 M ha, there is a clear need for a greater understanding of the cycling of these compounds within such systems. This thesis looks at the concentrations of several VSCs within agricultural and undisturbed ASS on the east coast of Australia. Initial measurements of sulfur dioxide (SO2) were made using passive diffusion samplers, which were followed by two detailed field-based studies looking at the concentrations and fluxes of both SO2 and hydrogen sulfide (H2S) using flux-gradient micrometeorological techniques. These novel results indicated that this agricultural ASS was a substantial source of atmospheric H2S (0.036-0.056 gSm-2yr-1), and SO2 (0.095-0.31 gSm-2yr-1), with flux values equating to many other salt- and freshwater marshes and swamps. The flux data also suggested that the ASS could be a continual source of H2S which is photo-oxidised during the daytime to SO2. Measurements of both compounds showed separate, inverse correlations to temperature and moisture meteorological parameters indicating possible contributing and / or causal release factors. Further identification of these and other VSCs within ASS samplers was undertaken in the laboratory using gas chromatography in combination with solid-phase microextraction. Although SO2 and H2S were not discovered within the headspace samples, two other VSCs important in atmospheric sulfur cycling and trace metal geochemistry were quantified; dimethylsulfide (DMS; &gt 300??g/L) and ethanethiol (ESH &gt 4??g/L). The measurements of H2S, DMS and ESH are the first quantifications with Australian ASS, and they may be important for refining regional or local atmospheric sulfur budgets, as well as interpreting previous SO2 emissions from ASS. Ultimately this thesis further enhances our understanding of the cycling of VSCs within acid sulfate systems.

Pasture plants already adapted to acidic soil conditions are required as part of an integrated approach (with lime amelioration) to managing acid soils on the Tablelands of New South Wales, Australia. The objective of this thesis is to evaluate the usefulness of Austrodanthonia species for this purpose. The material evaluated in this study was collected during a previous survey of the distribution of Austrodanthonia on the Central, Southern and Monaro Tablelands of New South Wales. It was hypothesised that the genus Austrodanthonia has a wide range of tolerance to acid soils. A series of experiments that provided information on the growth and physiology of Austrodanthonia in relation to soil acidity, with a view to the identification and eventual domestication of the most promising plant material have been conducted through pot, hydroponics and field investigations. Firstly, soils were acidified or limed to obtain a range of soil pH and Al concentrations. This experiment showed that adding aluminium sulfate and calcium carbonate followed by washing excess salts with water is a simple, rapid and convenient method for adjusting soil pH for pot experiments. The pH of the amended soils remained relatively unchanged eight months after treatment. The experimental set-up also resulted in a wide range of soluble Al (2-52 mg/kg) across the soils. The relative Al-tolerance of 183 accessions from 15 Austrodanthonia species was tested in a pot experiment using a range of soil pH. Emergence, survival and growth of all accessions were drastically reduced by high soil acidity (pH 3.9, P < 0.001). About 11% of plants emerged at pH 3.9, whereas at pH 4.4 and 5.3, ~72% of plants emerged. Accessions exhibited large variation within and between species in their tolerance to soil acidity. From the species/accessions tested, 49 accessions from eight species were selected for further study (on the basis of being more acid tolerant). Hydroponic experiments conducted in the glasshouse evaluated: (i) formulation of nutrient solution with a stable pH, (ii) effectiveness of the formulation using tap water and deionised water and (iii) estimation of free ion activities of Al and Mn in the nutrient solution and their effects on Austrodanthonia growth. These experiments showed that a NO3-N/NH4-N ratio of 9:4 is the most appropriate ratio to obtain a stable pH 4.0 without affecting plant growth; that there was little difference between tap water and deionised water on the ionic effects of Al and Mn, and plant-size did not play a role on accession survival and that accessions of Austrodanthonia could grow well within a wide range of pH (3.5-5.5), Al (50-250 �M) and Mn (100-2000 �M). Growth of Austrodanthonia accessions declined under high acidity (pH < 3.5) and Al (300 �M), but tolerated high concentrations of Mn (2000 �M). Root-tips stained with hematoxylin grouped accessions in a similar way to the pot and hydroponic experiments for most of the accessions tested. The intensity of root staining with hematoxylin and the differential distribution of Al in the shoots and roots provided an indication that different tolerance mechanisms may be involved with Austrodanthonia accessions. It appears that both exclusion and internal mechanisms may operate for Al- and Mn-tolerance. A field experiment was conducted at Carcoar (33037�S, 149013�E, elevation 800 m) using gradients in soil pH and Al available on-site to grow selected accessions of Austrodanthonia. The accessions exhibited a range of responses to soil acidity. The accession responses to acidity from the pot and hydroponic experiments were similar to those obtained in the field, especially where Al was present as a low Al-challenge. Overall, this study shows that Austrodanthonia exhibits a wide range of acid tolerance between species and accessions within species. Among the species tested, A. duttoniana and A. fulva appeared to have the greatest commercial potential, because of their productivity and acid tolerance. The variability that exists in the accessions may be exploitable in breeding and selection programs for improved cultivars.

The theme of this thesis is a comparison of selected quality indicators of samples from single-flower honeys from the area of the Czech Republic and honeys from different retail chains. The theoretical part focuses on the characteristics of the individual kinds of honey and how different their composition is. There are described basic physical and chemical requirements for honey including sensory requirements which are specified in Regulation No.76/2003 Code. The practical part contains a physically-chemical analysis according to the Harmonized methods of European Honey and a sensory evaluation of selected single-flower honeys (honeydew, acacia, lime, sunflower and rape). There were analysed twenty samples of honey from Czech beekeepers and fifteen samples of honey bought in different retail chains in the Czech Republic. Subsequently, these parameters were monitored - water content and acidity. Next step was a test for evidence of disruption by starchy sugar and malt extracts. Then, sensory requirements such as colour, smell, taste and consistence were evaluated. The conclusion of the comparison of honey samples indicates that individual honey samples differed the most in the taste and smell criteria and in addition the samples were often disrupted by starchy sugar and malt extracts. The samples collected from the beekeepers from the area of the Czech Republic complied with Regulation No.76/2003 Code. On the contrary, the samples from the chosen retail chains in the Czech Republic weren't in accordance with the criteria specified in Regulation No.76/2003 Code.

The aim of the thesis was to evaluate the acidity and viscosity of natural yoghurt depending on the different addition of skimmed milk powder and using of the methods of sensory analysis to evaluate the perception of these properties by young consumers. Part of this work was to analyse acidity and viscozity in selected kinds of natural yoghurts purchased in the market network of the Czech Republic (CR). The literature search mentions basic characteristic of yoghurts and their classification, acidity and rheological properities of yoghurts including the factors, which affect them and sensory analysis. In the experimental part of the study the acidity value, total solids and viscosity measurements were detected by physico-chemical analyses of samples of natural yoghurts. At samples of yoghurts with different content of skimmed milk powder the sensory evaluation was also subjected and the graphs of sensory profile were compiled. The observed results showed, that from the samples of yoghurts made in the laboratory was the most satisfactory sample containing 10 % of skimmed milk powder. At samples purchased in the market network of CR were detected very low leveles of titratable acidity.