Made available in DSpace on 2014-06-11T19:31:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-12Bitstream added on 2014-06-13T19:41:12Z : No. of bitstreams: 1 cardoso_mjl_dr_botfmvz.pdf: 248290 bytes, checksum: 9109a7b559aa1fe60811340d1a417214 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os efeitos do hipertireoidismo experimental (150 g/kg/dia/42 dias) na homeostase do cálcio e nos marcadores do metabolismo ósseo foram estudados em 14 gatos sem raça definida, com idade entre um e três anos. Houve uma clara tendência de aumento das concentrações séricas de PTH intacto a partir do momento inicial com diferença significativa entre este e os demais momentos. O cálcio ionizado demonstrou uma diminuição significativa aos 14 dias em relação ao momento inicial e aos 42 dias em relação aos 14 dias. Os hormônios tireoidianos apresentaram correlação positiva com o PTH e negativa com o cálcio ionizado. Já a densidade mineral óssea (DMO) apresentou tendência de correlação negativa com o PTH a partir dos 28 dias. Observou-se correlação negativa do PTH com o cálcio ionizado aos 14, 28 e 42 dias. Conclui-se que o hipertireoidismo em gatos adultos jovens sem doenças concomitantes apresenta hiperparatireoidismo secundário. As concentrações séricas da OC apresentaram diferença significativa (p<0,05) entre si, nos quatro momentos. O ICTP, um marcador específico da reabsorção óssea, não apresentou diferença significativa entre os momentos. Provavelmente o remodelamento ósseo foi provocado pelo estado hipertireóideo, visto que tanto a OC como o ICTP apresentou forte correlação positiva com a TT4 e um pouco inferior com a FT4. A FT4 não apresentou correlação positiva com o ICTP, excetuando-se aos 28 dias. Observou-se baixa correlação, em todos os momentos, entre os marcadores do metabolismo ósseo e a densidade mineral óssea. Conclui-se que o excesso dos hormônios tireoidianos em gatos provocou aumento do remodelamento ósseo visto que ocorreu alta correlação entre estes hormônios e os marcadores do metabolismo ósseo. O hipertireoidismo provocou diminuição da DMO óssea, porém a OC e o ICTP apresentaram baixa correlação com esta variável. / The effect of experimental hyperthyroidism (150 g/kg/day/42 days) on calcium homeostasis and markers of bone metabolism was studied in fourteen shorthair cats from one to three years of age. Serum concentrations of unbroken PTH had a clear tendency to increase from beginning with significant differences from the initial to other moments. The ionized calcium significantly decreased at the 14 days in comparison to the initial moment and at the 42 days in comparison to the 14 days. The thyroid hormones showed positive correlation with PTH and negative with ionized calcium. In contrast, bone mineral density had a tendency of negative correlation with the PTH from the 28 days. Negative correlation of the PTH and calcium ionized was observed at 14, 28 and 42 days. In the present study, hyperthyroidism in young adult cats without concomitant illnesses did not present secondary hyperparathyroidism. However, increase of PTH and reduction of ionized calcium were observed. Serum concentrations of osteocalcin (OC) were significantly different among all four moments. The carboxi-terminal telopeptides of collagen type I (ICTP), a specific marker of the bone reabsorption, did not significantly differ (p<0.05) between moments. Bone turnover was probably caused by the hyperthyroid state, since OC and ICTP presented strong positive correlation with TT4 and a little less with free T4 (FT4). The FT4 did not present positive correlation with the ICTP, excepting at the 28 days. Positive correlation in all the moments between markers of bone metabolism and bone mineral density was very low. In conclusion, the high correlation between thyroid hormones and markers of bone metabolism indicates that the excess of thyroid hormones in cats may cause an increase of the bone turnover. Moreover, hyperthyroidism may cause reduction of the bone DMO, although OC and the ICTP had low correlation with DMO.

Made available in DSpace on 2014-06-11T19:32:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-09Bitstream added on 2014-06-13T19:43:14Z : No. of bitstreams: 1 mendonca_pc_dr_botfca.pdf: 892807 bytes, checksum: c81f229a150e1ff79516536ed6fe7f98 (MD5) / A espécie Stryphnodendron adstringens (Leguminosae) é conhecida popularmente como barbatimão e o extrato das cascas é utilizado como cicatrizante. O objetivo deste trabalho foi estudar a variabilidade genética da espécie utilizando o marcador molecular de polimorfismo de comprimento amplificado (AFLP) e testar a transferência de microssatélites de Anadenanthera colubrina, Hymenaea courbaril e Copaifera langsdorffii. Foram coletados acessos localizados nos municípios de Cristalina, São João D’Aliança, Campo Alegre e Caldas Novas (GO); Delfinópolis, Luislândia, Lagoa Formosa, Sacramento e Araxá (MG) e Paranapanema, Cristais Paulista e Botucatu (SP). O DNA genômico foi extraído de folhas e as análises de polimorfismo seguiram as etapas de digestão, ligação, pré-amplificação e amplificação. Os produtos AFLP foram separados em gel desnaturante de poliacrilamida 6% com tampão TBE 1X. A eletroforese foi realizada em voltagem constante de 80W em temperatura máxima de 50ºC por 4 horas. O gel foi corado com solução de nitrato de prata e revelado em carbonato de sódio. Na análise por marcador AFLP foram produzidas 237 bandas polimórficas. A variabilidade dentro das populações foi maior (70,93%) que entre as populações (29,06%) com um valor de Fst 0.2906 indicando alta estruturação populacional. A população de Luislândia apresentou maior porcentagem de loci polimórficos (87,35), seguida da população de Cristalina (45,85). A menor variabilidade foi encontrada em Caldas Novas (22,92) e as demais ficaram na média (34,3). O Método da Média Aritmética não Ponderada (UPGMA) reuniu as populações em três grupos. Quanto aos testes de transferência de microssatélites, dos 20 iniciadores de A. colubrina testados, dez apresentaram resultados de transferência, porém somente um... / Stryphnodendron adstringens a Leguminosae species is popularly known as barbatimão and the extract of its barks is widely used as healing agent. The genetic variation of 12 populations of S. adstringens was determined in this study by using Amplified Fragment Length Polymorphism (AFLP) molecular markers transference of microsatellites of Anadenanthera colubrina, Hymenaea courbaril and Copaifera langsdorffii. Accessions were collected in the cities of Cristalina, São João D’Aliança, Campo Alegre and Caldas Novas (GO), Delfinópolis, Luislandia, Lagoa Formosa, Sacramento and Araxá (MG) and in Paranapanema, Cristais Paulista and Botucatu (SP). The genomic DNA was extracted from the leaves and the polymorphism analysis followed multiple steps including DNA digestion, ligation, pre-amplification and amplification. Amplification products were analyzed on denaturing polyacrylamide sequencing gel and running electrophoretic steps at 80 W with maximum temperature at 50ºC for 4 h. The gel was stained with silver nitrate solution and developed in sodium carbonate. The AFLP analysis conducted with three primer combinations using the EcoRI and MseI restriction enzymes generated 237 polymorphic bands. The AFLP binary data were used to determine allele frequencies. Population structure was evaluated performing analysis of molecular variance (AMOVA) which allowed the estimation of the total genetic variance among and inside populations. A descriptive analysis of the total variability was obtained by calculating the percentage of polymorphic loci. Genetic variance 4 within populations was higher (70,93%) compared to the differentiation estimated among populations (29,06%). The fixation index (Fst) was 0.2906 indicating highly significant population structuring. The population from Cristalina... (Complete abstract click electronic access below)

abstract: The purpose of this study was to identify acoustic markers that correlate with accurate and inaccurate /r/ production in children ages 5-8 using signal processing. In addition, the researcher aimed to identify predictive acoustic markers that relate to changes in /r/ accuracy. A total of 35 children (23 accurate, 12 inaccurate, 8 longitudinal) were recorded. Computerized stimuli were presented on a PC laptop computer and the children were asked to do five tasks to elicit spontaneous and imitated /r/ production in all positions. Files were edited and analyzed using a filter bank approach centered at 40 frequencies based on the Mel-scale. T-tests were used to compare spectral energy of tokens between accurate and inaccurate groups and additional t-tests were used to compare duration of accurate and inaccurate files. Results included significant differences between the accurate and inaccurate productions of /r/, notable differences in the 24-26 mel bin range, and longer duration of inaccurate /r/ than accurate. Signal processing successfully identified acoustic features of accurate and inaccurate production of /r/ and candidate predictive markers that may be associated with acquisition of /r/. / Dissertation/Thesis / Masters Thesis Communication Disorders 2017

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-13Bitstream added on 2014-06-13T19:57:01Z : No. of bitstreams: 1 figueiroa_fc_me_botfm.pdf: 867639 bytes, checksum: 19c301abfd98e5068beecab179f5144b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Por ser a maior causa de morte entre as fêmeas caninas, o câncer de mama desperta o interesse da comunidade científica, pois sua apresentação e evolução clínica são muito semelhantes aos casos de câncer de mama na mulher. No intuito de permitir a continuação dos estudos comparativos entre os tumores de cadelas e os das mulheres é fundamental a padronização da classificação histopatológica e imunoistoquímica. Por meio da técnica de Tissue microarray foi possível concentrar um grande número de amostras e compará-las numa mesma lâmina, permitindo que uma casuística maior pudesse ser analisada, evitando desperdícios de materiais e reagentes. A partir dos resultados da imunoistoquímica foi possível a reclassificação dos tumores de mama da cadela em Luminal A (RE+ e HER-2-) (36,36%), Luminal B (RE+ e HER-2 +) (9,09%), Basal (RE-, HER-2 - e p63 e/ou CK5 +) (37,88%) e Super-expressão de HER-2 (RE- e HER-2 +) (12,12%) assim como classificados em Medicina Humana. Além disso, foi realizada a marcação para a Catepsina D e proteína S100A4, para demonstrar o potencial metastático desses tumores. Os resultados permitem concluir que é possível a reclassificação dos carcinomas de mama em cadela assim como os tumores de mama em mulheres, promovendo um melhor entendimento das características moleculares por meio das imunoexpressões de proteínas. A Catepsina D e a proteína S100A4 se mostraram importantes na caracterização do potencial metastático, contudo novos estudos devem ser realizados para confirmar o papel desses marcadores nos carcinomas de mama metastáticos de cadelas e das mulheres. / For being the biggest cause of death between the canine females, breast cancer arises the interest of the scientific community, therefore its presentation and clinical outcome are very similar to the cases of breast cancer in the woman. In intention to allow the following of comparative studies between the tumors of dogs and of the women the standardization of the histopathogical and imunohistochemical classification is needed. By the technique of Tissue microArray it was possible to concentrate a great number of samples and to compare them in one same slide, allowing that a bigger casuistry could be analyzed, preventing the waste of materials and reagents. From the results of the imunohistochemistry the reclassification of the breast tumors of the dog was possible. They’re reclassified in Luminal A (RE+ and HER-2-) 36.36%), Luminal B (RE+ and HER-2 +) (9.09%), Basal (RE-, HER-2 - and p63 and/or CK5 +) (37.88%) and HER-2 Super-expression (RE- and HER-2 +) (12.12%) as well as classification in Medicine Human. Moreover, it was carried through the marking for Cathepsin D and protein S100A4, to demonstrate the metastatic potential of these tumors. The results allow concluding that the reclassification of breast carcinomas in dog as well as the breast tumors in women is possible, promoting a better agreement of the molecular characteristics by means of the imunoexpression of proteins. Cathepsin D and protein S100A4 had shown important in the characterization of the metastatic potential. However more studies must be carried through to confirm the paper of these markers in the metastatic breast carcinomas of dogs and of women.

Submitted by Lucas Bassi Costa null (lucasbassi_costa@hotmail.com) on 2018-03-28T13:48:37Z No. of bitstreams: 1 Dissertação Lucas Bassi.pdf: 2136145 bytes, checksum: 43df64ca19daca39fe3b36e18c78b20b (MD5) / Approved for entry into archive by Laura Akie Saito Inafuko (linafuko@assis.unesp.br) on 2018-03-28T14:20:35Z (GMT) No. of bitstreams: 1 costa_lb_me_assis.pdf: 2136145 bytes, checksum: 43df64ca19daca39fe3b36e18c78b20b (MD5) / Made available in DSpace on 2018-03-28T14:20:35Z (GMT). No. of bitstreams: 1 costa_lb_me_assis.pdf: 2136145 bytes, checksum: 43df64ca19daca39fe3b36e18c78b20b (MD5) Previous issue date: 2018-03-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O filo Cnidaria pode ser considerado um dos mais distintos do reino animal. Dentre suas subclasses, encontra-se Ceriantharia, constituída pelas anêmonas de tubo. Esses animais são até o momento um desafio para a sistemática, uma vez que após diversas propostas, nenhuma se fez unânime até o momento. Grande parte da divergência encontrada em classificar o grupo, deve-se aos métodos/materiais utilizados para análise. Sendo assim, o presente trabalho buscou, através de dados moleculares, estudar as relações de Ceriantharia dentre os Anthozoa e os demais Cnidaria e comparar os resultados obtidos pelos diferentes métodos de reconstruções filogenéticas. Para tal, foram utilizados marcadores ribossomais completos (28S e 18S). Por meio de softwares específicos, as sequências genéticas foram analisadas e as reconstruções foram realizadas seguindo dois dos métodos mais utilizados atualmente (máxima verossimilhança e inferência bayesiana). Tendo em mãos inúmeras ferramentas, o presente trabalho é uma oportunidade de gerar conhecimento e buscar conceitos mais precisos dentro da sistemática do grupo. / The Cnidaria phylum can be considered one of the most distinguished of the animal kingdom. Among them, there is the subclass Ceriantharia, constituted by the tube anemones. These animals are so far a challenge to systematics, since after several proposals, none has been considered as unanimous yet. Much of the divergence found in classifying the group is due to the methods / materials used for analysis. Thus, the present work sough trough molecular data, to study the relationships of Ceriantharia among the Anthozoa and the other Cnidaria and to compare the results obtained by the different methods of phylogenetic reconstruction. For this, complete ribosomal markers (28S and 18S), were used. By means of specific softwares, the genetic sequences were analyzed and the reconstruction were performed following two of the most commonly used methods (maximum likelihood and Bayesian inference). Having in hand numerous tools, the present work was a very important opportunity to generate knowledge and to search for more precise concepts within the systematics of the group.

Submitted by VALENTINA ROLDAN MONTES null (valentiniya@hotmail.com) on 2016-11-14T17:33:47Z No. of bitstreams: 1 dissertação_Valentina_Roldan.pdf: 1303188 bytes, checksum: 91f87b135d433e48cad11782f8d4380d (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-21T13:30:26Z (GMT) No. of bitstreams: 1 roldanmonter_v_me_jabo.pdf: 1303188 bytes, checksum: 91f87b135d433e48cad11782f8d4380d (MD5) / Made available in DSpace on 2016-11-21T13:30:26Z (GMT). No. of bitstreams: 1 roldanmonter_v_me_jabo.pdf: 1303188 bytes, checksum: 91f87b135d433e48cad11782f8d4380d (MD5) Previous issue date: 2016-10-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Considerando a importância das doenças que afetam o desempenho produtivo dos animais na indústria leiteira em todo o mundo é necessário implementar ferramentas moleculares que auxiliem na identificação e controle destas doenças. Quando ocorre alguma infecção em um organismo superior, existe aumento do número de células de defesa e o sistema imune inato proporciona uma linha de defesa contra os patógenos. Os “Toll Like Receptors” (TLR) são proteínas da membrana que desempenham um papel chave na imunidade, reconhecendo patógenos e, posteriormente, ativando as respostas. O presente estudo foi realizado para identificar SNPs no gene TLR4 bubalino e analisar suas associações com características de importância produtiva, incluindo a contagem de células somáticas (CCS). Foram utilizadas amostras de DNA de 130 búfalas da raça Murrah. A região codificante do gene TLR4 foi amplificada através de reações de PCR e posteriormente sequenciada. Os polimorfismos encontrados tiveram suas frequências alélicas e genotípicas calculadas e verificadas quanto ao equilíbrio de Hardy-Weinberg, além de serem utilizados para os estudos de associação. Foram identificados 13 polimorfismos do tipo SNP para as regiões sequenciadas do gene TLR4, sendo que a maioria encontra-se em região codificante. Encontrou-se associação significativa, com porcentagem de gordura dos Snps g514>C/T (P=0,0040) e g536>A/T (P=0,0035). As associações para CCS demostrou-se altamente significantes (p=<0,001) para todos os Snps (g322>G/A, g514>C/T, g536>A/T, g8338>A/C, g8341>A/G, g8342>T/G, g8343>G/A, g8345>A/G, g8413>A/G, g8428>G/A, g8438>A/C, g8578>G/T e g8582>A/C). Sugere-se que os Snp do gene TLR4 possam ser utilizados como marcadores moleculares em búfalos, já que foram verificadas suas associações com características como porcentagem de gordura e proteína, e contagem de células somáticas. / Molecular markers might be developed to investigate genetic variants associated to the disease and assist selection process in order to identify resistant animals. When the mammary gland is infected, there is an increase in the defense cells, also called somatic cells. It is a defense line of the immune system against pathogens. The “tool like receptors” TLR are membrane proteins that have an important role in the immunity, recognizing pathogens and activating adequate responses. The present study aimed to investigate the association of TLR4 gene SNPs with productive characteristics and SCC in buffaloes. The DNA was extracted from hair follicules of 130 Murrah buffaloes. The fragments were amplified by Polymerase Chain Reaction (PCR) and sequenced. Thirteen SNPs were found. Allelic and genotypic frequencies were calculated as well as the adhesion to Hardy-Weinberg equilibrium and the linkage disequilibrium (r2) and the association to the characteristic. For SCC was tested methodology linear generalized mixed model, assuming Poisson distribution. Bonferroni correction was applied for the number of SNPs. Thirteen SNP polymorphisms were identified in coding region of the TLR4 (g322>G/A, g514>C/T, g536>A/T, g8338>A/C, g8341>A/G, g8342>T/G, g8343>G/A, g8345>A/G, g8413>A/G, g8428>G/A, g8438>A/C, g8578>G/T, g8582>A/C). The SNPs g514>C/T and g536>A/T had significant association whit %G. All the SNPs were associated (p=0.001) whit the CCS. Other authors also reported the association of TRL4 SNPs to the trait. The results show that the SNPs of TLR4 gene can be used as molecular markers in buffaloes.

No description available.

O Brasil é país detentor de grande biodiversidade, no entanto pequena parcela dessa já foi estudada e catalogada. Os recentes avanços antrópicos sobre os ecossistemas naturais tem levado a sua rápida fragmentação e eliminação de alguns biótipos ainda não estudados ou catalogados. Nessa realidade de erosão genética acelerada encontra-se também espécies de jabuticabeira (Plinia sp.) que são endêmicas do Centro Sul/Sudoeste do Paraná, no ecossistema Floresta com Araucária. Medidas de conservação de germoplasma para uso atual e futuro, bem como táticas de manejo e conservação dos recursos naturais são preponderantes para reduzir ao mínimo os danos causados a biodiversidade brasileira. Para tanto é necessário entender a diversidade genética existente nos ecossistemas naturais, que é o insumo básico para a sobrevivência e evolução entre os indivíduos frente as modificações ambientais. No presente trabalho foi realizado a caracterização genética de 110 jabuticabeiras que constituem o banco ativo de germoplasma desta espécie na UTFPR – Câmpus Dois Vizinhos. Foi possível identificar a transferibilidade de 9 marcadores moleculares microssatélites (SSR) com caráter polimórfico para a população estudada, e realizar a padronização de reação de PCR para cada um deles. Da análise das jabuticabeiras do banco ativo de germoplasma chegou-se a conclusão de que o mesmo abrigou valor considerável de diversidade alélica. No entanto tal diversidade está mal distribuída, já que 11 indivíduos sozinhos já são capazes de representar 59,2% de todos alelos da coleção de 110 plantas. Os valores encontrados de heterozigosidade observada e conteúdo informativo (PIC) nessa subpopulação de 11 indivíduos foram superiores aos valores encontrados para o conjunto integral do banco ativo. O agrupamento dos indivíduos mostrou a existência de 8 diferentes grupos, sendo que 89 indivíduos ficaram no grupo 1, demonstrando o seu possível grau de parentesco e baixo nível de diversidade genética. / Brazil is a country of great biodiversity holder, however small portion of that has been studied and cataloged. Recent advances human activities on natural ecosystems has led to its rapid fragmentation and elimination of some biotypes still, not it studied or cataloged. In this reality of genetic erosion is also accelerated jabuticaba tree species (Plinia sp.). That are endemic from South Central / Southeastern Paraná State, in Araucaria forest ecosystem. Germplasm conservation measures for current and future use, as well as tactics for management and conservation of natural resources are crucial to minimize the damage caused to Brazilian biodiversity. So it is necessary to understand the genetic diversity in natural ecosystems, which is the basic input for the survival and evolution among individuals facing environmental changes. In the present study was to characterize genetic of 110 jabuticaba tree fruit, that constitute the germoplasm bank of jabuticaba tree fruit from UTFPR - Câmpus Dois Vizinhos. It was possible to identify transferability of 9 microsatellite markers (SSR) with polymorphic character for the population studied, and it carry out standardization of PCR reaction for each of them. The analysis of plant germoplasm bank came to the conclusion that houses a considerable amount of allelic diversity, but this diversity is poorly distributed, since 11 individuals alone are already able to represent 59.2% of all alleles of the collection of 110 plant. The found values of, observed heterozygosity and information content (PIC) in this subpopulation of 11 individuals were higher than the values found for the full set of the germoplasm bank. The grouping of individuals showed the existence of 8 different groups, and 89 subjects were in group 1, demonstrating a possible relationship and low level of genetic diversity.

Thesis (Masters Diploma (Technology)--Cape Technikon, Cape Town, 1986 / Child psychiatrists have become increasingly aware of the existence. of affective disorders in prepubertal and pubertal patients. This has led to the investigation of possible biological factors contributing to the disorders. Due to the lack of availability of human brain material, different parameters have been investigated in the periphery in order to obtain information regarding the aetiology of major depressive disorder. The neurotransmitters, NA, 5-HT and DA have been implicated in depression. Levels of the metabolites of these transmitters have been measured in plasma, urine and CSF of adult depressed patients. Two other peripheral "tools" used in the study of major depressive disorder are blood platelets and lymphocytes. The former contain cr 2 -adrenoceptors and imipramine binding sites (indicative of 5-HT uptake into the platelet) and the latter S-adrenoceptors. Platelets have been widely used as a model for indirectly evaluating changes in central cr2-adrenoceptor and imipramine binding whereas lymphocytes have been used to measure changes in S-adrenoceptor binding and activity in adults with major depressive disorder.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017. / Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked. The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies. Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks. A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated.