Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-25T20:01:17Z No. of bitstreams: 1 Thaís_Marcon2017.pdf: 1321093 bytes, checksum: deb59ddc497de55cd34d9a12affcf451 (MD5) / Made available in DSpace on 2017-09-25T20:01:17Z (GMT). No. of bitstreams: 1 Thaís_Marcon2017.pdf: 1321093 bytes, checksum: deb59ddc497de55cd34d9a12affcf451 (MD5) Previous issue date: 2017-02-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Parapiptadenia rigida is a native-tree species with fast natural regeneration, so, it has been recommended to mixed reforestation in degraded areas. The seedlings’ availability of native species in nurseries is fundamental to their management in projects of environmental recovery. The quality of nursery seedlings depends on factors such as substrate application with good quality. Organic compounds have been tested as alternative substrates for a sustainable cropping yield, to reuse organic wastes and minimize the environmental impacts. Thus, the present study aimed at evaluating the substrate influence on antioxidant enzymatic activity, for both seedlings’ emergence and initial growth of angico-red seedlings (Parapiptadenia rigida). The substrates were formulated from the composting of agroindustrial wastes with different carbon sources, totaling six treatments: commercial substrate (control); Organic cotton-based substrate; Organic substrate based on sugarcane bagasse; Organic substrate based on Napier grass; Organic substrate based on pruning of trees and organic substrate based on sawdust. The chemical and physical determinations of the studied substrates were carried out under laboratory conditions. Two trials were carried out, the first one in the laboratory, completely randomized, whose following evaluated emergence parameters of angico-red seedlings were: relative emergence frequency, emergency synchronization, emergence speed index, mean emergence time and the activity of antioxidant enzymes of angico-red seedlings. The second experiment was carried out in a greenhouse, following a design of randomized blocks. The following data of initial growth were monthly evaluated: height, stalk diameter and number of leaflets in angico-red seedlings. Root dry mass, aerial part dry mass, Dickson quality index, nutrient content, enzymatic activity and membrane damage of angico-red seedlings were recorded by the end of 120 days. Finally, the commercial substrate presented the best results for angico-red seedlings’ emergence, but during their growth, the alternative organic substrates showed advantages over the commercial one in the final development of angico-red seedlings. The organic substrates based on cotton and Napier grass provided a low percentage of emergence of angico-red seedlings, as well as the lowest root and shoot length answers, and the highest activity of peroxidase enzyme. This result has shown that an oxidative stress had occurred and the activity of repair enzymes was not enough when compared to the damages caused by the substrates. On the other hand, the organic substrates based on cane bagasse and sawdust showed the best results in emergence and development of angico-red seedlings. They also provided the highest values of Dickson`s seedlings quality index. According to these results, it is possible to assert that the organic substrates formulated by the composting from different carbon sources affected in a different way antioxidative enzymes activity of angico-red seedlings. And that the best indicated substrates to produce angico-red are based on sawdust and sugarcane bagasse. / A Parapiptadenia rigida é uma espécie arbórea nativa que apresenta rápida regeneração natural, por isto é recomendada para reflorestamentos mistos em áreas degradadas. A disponibilidade de mudas de espécies nativas em viveiros é de fundamental importância para a utilização de tal espécie em projetos de recuperação ambiental. A qualidade das mudas em viveiros depende entre outros fatores do uso de um bom substrato. Compostos orgânicos vêm sendo testados como substratos alternativos na produção sustentável de mudas, para o reaproveitamento dos resíduos e minimização dos impactos ambientais. Desta maneira, o objetivo do presente trabalho foi avaliar a influência dos substratos na atividade enzimática antioxidante, na emergência de plântulas e no crescimento inicial de mudas de angico-vermelho (Parapiptadenia rigida). Os substratos foram formulados a partir de compostos orgânicos provenientes da compostagem de resíduos agroindustriais com diferentes fontes de carbono, totalizando seis tratamentos: substrato comercial (SC); substrato orgânico à base de algodão (SA); substrato orgânico à base de bagaço de cana-de-açúcar (SB); substrato orgânico à base de capim-napier (SN); substrato orgânico à base de poda de árvores (SP) e substrato orgânico à base de serragem (SS). Foram determinadas as características químicas e físicas dos substratos em condições de laboratório. Foram realizados dois experimentos: o primeiro em laboratório seguindo um delineamento inteiramente casualizado, no qual foram avaliados os seguintes parâmetros de emergência de plântulas de angico-vermelho: frequência relativa de emergência, sincronização de emergência, índice de velocidade de emergência, tempo médio de emergência e atividade das enzimas antioxidantes das plântulas de angico-vermelho. O segundo experimento foi realizado em casa de vegetação e seguiu um delineamento em blocos casualizados. Foram registrados o crescimento inicial pela avaliação mensal da altura, o diâmetro do caule e o número de folíolos das mudas de angico-vermelho. Ao final de 120 dias foram avaliados: a massa seca da raiz, a massa seca da parte aérea, o índice de qualidade de Dickson, o teor de nutrientes das mudas de angico-vermelho, a atividade enzimática e o dano de membrana das mudas de angico-vermelho. De maneira geral, o substrato comercial apresentou os melhores resultados na emergência das plântulas de angico-vermelho, porém, ao longo do crescimento, os substratos orgânicos alternativos apresentaram vantagens sobre o substrato comercial no desenvolvimento final das mudas de angico-vermelho. Os substratos orgânicos à base de algodão e capim-napier proporcionaram baixa porcentagem de emergência das plântulas de angico-vermelho, além dos menores valores de comprimento de raiz e parte aérea e maior atividade da enzima peroxidase nas mudas de angico-vermelho. Esse resultado demonstra que ocorreu estresse oxidativo e que a atividade das enzimas de reparo não foi eficiente contra os danos ocasionados pelos substratos. Já os substratos orgânicos à base de bagaço de cana e serragem apresentaram os melhores resultados na emergência de plântulas e no desenvolvimento de mudas de angico-vermelho e proporcionaram os melhores valores de índice de qualidade de mudas de Dickson. Diante dos resultados, é possível afirmar que os substratos orgânicos formulados pela compostagem com diferentes fontes de carbono afetaram de maneira diferenciada a atividade das enzimas antioxidativas das mudas de angico-vermelho. E substratos mais indicados para a produção de angico-vermelho são os substratos orgânicos à base de serragem e bagaço de cana-de-açúcar.

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2018-07-10T19:03:49Z No. of bitstreams: 2 Erly_Porto2018.pdf: 629278 bytes, checksum: 0e4cf8a84230328bfeaab2b5e568a733 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-10T19:03:49Z (GMT). No. of bitstreams: 2 Erly_Porto2018.pdf: 629278 bytes, checksum: 0e4cf8a84230328bfeaab2b5e568a733 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Plant species can interact with each other through the production and release of chemical compounds released into the environment, such an event is known as allelopathy. The objective of the present study was to investigate the allelopathic action and oxidative stress of the aqueous extract of Bauhinia forficata L. on seeds during the germination process and seedlings during the Phaseolus vulgaris development phase. The germination behavior, allelopathic activity index, initial growth and activity of antioxidant enzymes were studied at different times of seed imbibition, in the cotyledon (reserve tissue) and in the embryonic axis and seedlings, for aerial part and root target species. The results indicated that during the germination phase there was negative interference of B. forficata extracts on the seeds for germination, speed index and mean germination time, as well as the allelopathic activity index. In relation to the enzymatic activity, a high enzyme activity was observed at the beginning of seed imbibition, between 3 and 6 hours for the cotyledon and high activity in the embryonic axis at the end of the germination process, between 12 and 24 hours of imbibition. The increase of the extract proportions of the leaves of B. forficata affected the enzymatic activities in the germination process of the bean seeds, resulting in a delay of the germination. As for the development phase, there was reduction of the average length and dry mass of the root as the proportion of extract used increased. the levels of lipid peroxidation for both shoot and root were high, as well as the activity of the catalase enzyme for the roots was also elevated when submitted to the treatments with the presence of the extract. Thus, the increase in the proportion of B. forficata extract negatively affected the initial development, being the primary root elongation more sensitive, causing severe damage to the membranes of the bean seedlings roots. / As espécies vegetais podem interagir entre si por meio da produção e liberação de compostos químicos liberados no ambiente, tal evento é conhecido como alelopatia. Desta forma, o objetivo do presente estudo foi investigar a ação alelopática e o estresse oxidativo do extrato aquoso de Bauhinia forficata L. sobre sementes de Phaseolus vulgaris, durante o processo de germinação e desenvolvimento das plântulas. Para isso, foram avaliados o comportamento germinativo, o índice de atividade alelopática, o crescimento inicial e a atividade de enzimas antioxidantes em diferentes tempos de embebição das sementes, no cotilédone (tecido de reserva) e no eixo embrionário e plântulas, para a parte aérea e raiz da espécie alvo. Os resultados indicaram que durante a fase de germinação houve interferência negativa dos extratos de B. forficata sobre as sementes para as variáveis: germinação, índice de velocidade e tempo médio de germinação, como também para o índice de atividade alelopática. Em relação a atividade enzimática, foi verificado uma alta atividade das enzimas no início da embebição das sementes, entre 3 e 6 horas para o cotilédone e elevada atividade no eixo embrionário ao final do processo germinativo, entre 12 e 24 horas de embebição. O aumento das proporções de extrato das folhas de B. forficata afetaram as atividades enzimáticas no processo germinativo das sementes de feijão resultando um atraso da germinação. Já para a fase de desenvolvimento, houve redução do comprimento médio e massa seca da raiz conforme o aumento das proporções de extrato utilizados. Os níveis de peroxidação lipídica tanto para parte aérea e raiz foram elevados, assim como a atividade da enzima catalase para as raízes também foi elevado quando submetidos aos tratamentos com a presença do extrato. Desta forma, o aumento das proporções de extrato de B. forficata L. afetou negativamente o desenvolvimento inicial, sendo o alongamento da raiz primaria mais sensível, provocando danos acentuados as membranas das raízes de plântulas de feijão.

Uma das alternativas para reduzir os efeitos negativos das altas temperaturas nas plantas e, consequentemente a perda na produção e qualidade é a utilização de indutores de tolerância. Dentro deste contexto, a L-arginina, se apresenta como uma alternativa, por ser um dos aminoácidos mais funcionais e precursora de importantes compostos na regulação metabólica das plantas, com efeito na atenuação do estresse abiótico. O objetivo deste trabalho foi avaliar o efeito da aplicação foliar de diferentes doses de L-arginina (0; 0,15; 0,25; 0,5; 1,0 e 2,0 g L-1) na fisiologia, produção e qualidade do tomate cultivar Pizzadoro cultivado em ambiente protegido no período de verão. Para avaliação do efeito da L-arginina na fisiologia, foram feitas análises de indicadores de estresse dos compostos malonaldeído (MDA) e peróxido de hidrogênio (H2O2), das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT) e ascorbato peroxidase (APX), teores de aminoácidos livres e teores de nutrientes nas folhas de tomateiro. Na produção foram determinadas a produção total (PT), a produção com presença de defeitos (PRDEF), a produção não comercial (PRNC) e a produção comercial (PC) com a classificação de calibre pequeno (PROP), médio (PROM) e grande (PROG). Além disso, foram determinados o número de frutos totais (NFT), número de frutos com presença de defeitos (NDEF), número de frutos não comerciais (NFNC) e número de frutos comerciais (NFC) com classificação de calibre pequeno (NFP), médio (NFM) e grande (NFG). Amostras de frutos maduros foram colhidas para a determinação de sólidos solúveis (SST), pH da polpa, ácido ascórbico (AA) e acidez total titulável (ATT) para determinação da qualidade do tomate. A aplicação de 1,0 g L-1 de L-arginina diminuiu o teor de MDA, e aumentou a atividade das enzimas CAT e APX. Além disso, essa dose do aminoácido aumentou a PC, PT, NFC, NFT e diminuiu a produção de NFNC. / Tolerance inductor products are one of the alternatives to reduce the negative effects of abiotic factors in plants, for instance the decrease of crop yield and quality. In this context, L-arginine is one option of this products to mitigate abiotic plant stress, due to its importance as a functional amino acid and precursor of metabolic plant compounds. Hence, the project objective was to evaluate the exogenous foliar application of different rates of L-arginine (0; 0.15; 0.25; 0.5; 1.0 e 2.0 g L-1) on physiology, yield and quality of tomato cultivar Pizzadoro growth in protected enviroment during Summer. Physiological effect were analized by markers of oxidative stress, as malondialdehyde (MDA) and hydrogen peroxide; activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) enzymes; free amino acids and nutrient contents in tomato leaves. Yield was estimated by total production (TP), production of defective fruit (PDF), non-commercial fruit production (NCFP) and commercial fruit production (CP). CP was classified as small (SPRO), medium (MPRO) and large (LPRO) sizes. Number of total fruit (NTF), number of defective fruit (NDF), number of non-commercial fruit (NNCF) and number of commercial fruit (NCF) were classified as small (NSF), medium (NMF) and large (NLF) sizes. Sample of mature tomatoes were harvested to assess quality, by content of soluble solids (SST), pH of tomato pulp, ascorbic acid (AA) and titratable acidity (TA). Application of L-arginine at rate of 1.0 g L-1 reduced MDA and increased CAT and APX. Besides physiological aspects, this level of amino acid increased CP, TP, NCF, NTF and decreased NNCF.

Abstract Breast cancer is the leading cause of death from cancer among Finnish women, but the ultimate causation of carcinogenesis still remains unclear. Reactive oxygen species (ROS) is a collective term for several types of reactive oxygen metabolites that are continuously generated in human cells mainly as by-products of aerobic respiration. ROS, including nitric oxide and its derivatives, play highly important roles in cell physiology. If ROS production exceeds the capacity of detoxification systems, principally antioxidant enzymes, oxidative stress is said to occur. This state is known to contribute to all stages of carcinogenesis. To explore the widely unstudied role of ROS and cell redox state modulating enzymes in breast carcinomas, the extent of ROS-derived macromolecule damage and the expression of the vast majority of known antioxidant enzymes were assessed in a large series of breast carcinomas, and the results were compared to the patients' clinicopathological parameters. The results were also compared to angiogenesis, DNA repair enzymes, cell proliferation, NF-κB, p53 expression, and survival. Immunohistochemistry was the main method applied, but western blotting and immunoelectron microscopy were also used. There is extensive oxidative damage in breast carcinomas, which seems to associate with tumor development. Oxidative macromolecule damage is notable even in stage I tumors. Cell redox state regulating enzymes, such as peroxiredoxin V, thioredoxin, thioredoxin reductase, and glutamate-cysteine ligase, associate with more aggressive phenotypes of tumors, including larger primary tumors, growth of metastases, increased cell proliferation, and poor differentiation. This indirectly suggests that cell redox state modulating enzymes may be inductive of tumor promotion in an oxidated environment. The results of this thesis support the importance of ROS in all stages of carcinogenesis. These observations are largely in line with the previous studies on different carcinomas, but there seem to be certain carcinoma type specific differences in the expression of these enzymes. Since the expression of given cell redox state modulating enzymes distinctly associates with clinicopathological parameters, these enzymes may be useful as prognostic indicators and facilitate the choice of appropriate treatment in the future.

The respiratory system is a target for environmental oxidants from airborne pollution and other contaminants. Chronic exposure may result in inflammatory conditions such as allergies and asthma. The ability of the body to counteract oxidation is dependent on the oxidative status of the individual, and can also benefit from the use of medicinal plant preparations such as Withania somnifera (WS), which is accredited with antioxidant and antiinflammatory properties. Selenium is an important cofactor of antioxidant enzymes such as glutathione peroxidase. A deficiency of Se will result in decreased antioxidant enzymes levels and a poor response to oxidative damage. The aim of this study was to determine the antioxidant content and activity of WS, as well as its in vitro effects with seleno-L-methionine (Se-Met), the major component of dietary selenium, in a physiologically relevant cell model system. Little is known about the combinational effects of non-enzymatic and enzymatic antioxidants i.e., WS in combination with Se-Met, and these effects were also quantified. The antioxidant content (total phenolic (TPC) and flavonoid content (TFC)) and activity (2,2- diphenyl-2-picrylhydrazyl (DPPH), trolox equivalent antioxidant capacity (TEAC)) and oxygen radical absorbance capacity (ORAC) of a water extract of WS, as traditionally prepared and used, was determined. The intracellular and total protection of WS alone (0-33.33 mg/ml) and in combination with Se-Met (0-33.33 pg/ml) (range: ½-100x RDA) was evaluated in a standard cell line, the SC-1 fibroblast cell line and in physiologically relevant primary cultures of chick embryo lung cells (CELC) using the 2’,7’-dichlorofluorescein diacetate (DCFH-DA) assay. Water extracts of WS, as traditionally consumed, were found to possess significant antioxidant content and activity. For TPC and TFC, WS was found to contain 4.84 g CE/100 g DW, and 355 mg CE/100 g DW respectively. For DPPH, the IC50 of WS was 56.34 mg/ml, and the antioxidant activity of WS was 274.8 μmol TE/g. For TEAC, the IC50 of WS was 60.3 mg/ml, and the antioxidant activity of WS was 2.2 mmol TE/g. Using ORAC, the antioxidant activity of WS was found to be 15.05 μM TE/g. WS and Se-Met exhibited both pro-oxidant and antioxidant effects in the DCFH-DA assay and this may be a function of concentration, as well as combinations of WS and Se-Met ratios. Data indicates that both WS and Se-Met, alone and in combination, elicit protection via the intracellular (at all concentrations) and extracellular (at higher concentrations) compartment of the SC-1 cell. A synergistic interaction is observed extracellularly between WS and Se-Met, with mostly additive effects occurring intracellularly. For CELC, WS and Se-Met alone both demonstrated total protective effects at almost all concentrations, and intracellular protective effects at higher concentrations. The combination of WS and Se-Met provided total and intracellular protection to the CELC at the highest concentration combination. Antagonism between WS and Se-Met was observed at low concentrations in the total protection assay, with weak synergism and antagonism occurring at higher concentrations. Synergism between WS and Se-Met was observed at low concentrations intracellularly, with antagonistic interactions occurring at higher concentrations. In conclusion, WS and Se-Met, alone and in combination at non-cytotoxic concentrations, displayed significant cellular protection against oxidative damage and this was a function of cell line, concentration and ratios between WS and Se-Met. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Anatomy / unrestricted

Orientador: Gisela Ferreira / Resumo: Para que as plantas conseguissem conquistar o ambiente terrestre, foi necessário desenvolver habilidades que as tornassem capazes de sobreviver aos desafios de seu habitat, dentre as quais estão o desenvolvimento de mecanismos de tolerância à dessecação das sementes. Espécies que habitam locais com grande disponibilidade de água tendem a produzir sementes recalcitrantes e por outro lado, as espécies que habitam locais secos, como os Cerrados, tendem a produzir sementes ortodoxas, conseguindo tolerar períodos de seca sem acumular danos que prejudiquem a germinação. Dentre os sistemas que atuam no mecanismo de tolerância à dessecação estão a atividade de enzimas antioxidantes, o acúmulo de açúcares e a atividade das proteínas da embriogênese tardia (LEA). A família Annonaceae possui espécies inseridas em habitats contrastantes, como a Annona crassiflora, oriunda do Cerrado e a Annona glabra, oriunda de manguezais o que as torna interessantes para avaliar se suas sementes apresentam diferentes respostas frente à tolerância à dessecação. Para alcançar esse objetivo, sementes das duas espécies foram coletadas e avaliadas após submissão a diferentes níveis de secagem (teor inicial de água, 20%, 10% e 5%) e secagem seguida de reidratação. Foram realizados testes de germinabilidade, quantificação enzimática (superóxido dismutase (SOD) (EC 1.15.1.1), peroxidase (POD) (EC 1.11.1.7) e catalase (CAT) (EC 1.11.1.6)); de açúcares (frutose, galactose, glicose, manose, sacarose e trealose); ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order for plants to conquer the terrestrial environment, it was necessary to develop skills that would enable them to survive the challenges of their habitat, including the development of seed desiccation tolerance mechanisms. Species that inhabit places with high water availability tend to produce recalcitrant seeds and, on the other hand, species that inhabit dry places, such as Cerrados, tend to produce orthodox seeds, being able to tolerate periods of drought without accumulating germinating damage. Systems that act on the desiccation tolerance mechanism include antioxidant enzyme activity, sugar accumulation, and late embryogenesis (LEA) protein activity. The Annonaceae family has species in contrasting habitats, such as Annona crassiflora, from the Cerrado and Annona glabra, from mangroves, which makes them interesting to evaluate if their seeds have different responses to desiccation tolerance. To achieve this goal, seeds of both species were collected and evaluated after submission to different drying levels (initial water content, 20%, 10% and 5%) and drying followed by rehydration. Germinability, enzymatic quantification (superoxide dismutase (SOD) (EC 1.15.1.1), peroxidase (POD) (EC 1.11.1.7) and catalase (CAT) (EC 1.11.1.6) tests were performed; sugars (fructose, galactose, glucose, mannose, sucrose and trehalose); determination of LEA proteins and lipoperoxide content. The results showed that A. crassiflora seeds were able to tolerate drying up to 10% water co... (Complete abstract click electronic access below) / Mestre

Orientador: João Domingos Rodrigues / Resumo: Perante a atual demanda hídrica para manutenção de cultivos intensos e sucessivos, faz-se necessária a busca de alternativas para o manejo correto da água a fim de reduzir seu desperdício. Uma dessas alternativas se concentra na utilização de águas de qualidade inferior como, por exemplo, águas salobras. No entanto, uso de águas salobras podem ocasionar diversas alterações no metabolismo das plantas, necessitando de estratégias que permitam o uso dessas águas. Na busca dessas alternativas, busca-se substâncias biológicas ou sintéticas que gerem respostas fisiológicas e bioquímicas que promovam a adaptação das plantas às condições ambientais adversas, a exemplo do óxido nítrico (NO). Partindo desse pressuposto, objetivou-se com este trabalho avaliar o efeito atenuante do óxido nítrico em plantas de alface crespa, cv. Vera, cultivada sob estresse salino. O experimento foi realizado em casa de vegetação nos meses de abril e maio de 2019, da Fazenda Experimental de São Manuel da FCA, localizada no município de São Manuel/SP. O delineamento experimental adotado foi o de blocos ao acaso, em esquema fatorial de 5 x 2, sendo o primeiro fator compreendido por cinco concentrações de nitroprussiato de sódio (NPS) (0, 50, 100, 150 e 200 µmol) e o segundo fator foi composto por dois níveis salinos da água de irrigação (0,2 e 3,5 dS m-1, respectivamente, sem e com estresse salino), com quatro repetições. As concentrações de NPS foram aplicadas semanalmente (via foliar), totalizando três ap... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In view of the current water demand for maintaining intense and successive crops, it is necessary to search for alternatives for the correct management of water in order to reduce its waste. One of these alternatives focuses on the use of lower quality water, such as brackish water. However, the use of brackish water can cause several changes in the metabolism of plants, requiring strategies that allow the use of these waters. In the search for these alternatives, biological or synthetic substances are sought that generate physiological and biochemical responses that promote the adaptation of plants to adverse environmental conditions, such as nitric oxide (NO). Based on this assumption, the aim of this study was to evaluate the attenuating effect of nitric oxide on crisp lettuce plants, cv. Vera, grown under salt stress. The experiment was carried out in a greenhouse in the months of April and May 2019, at the São Manuel da FCA Experimental Farm, located in the municipality of São Manuel / SP. The experimental design adopted was that of randomized blocks, in a 5 x 2 factorial scheme, the first factor being comprised of five concentrations of sodium nitroprusside (SNP) (0, 50, 100, 150 and 200 µmol) and the second factor was composed of two saline levels of irrigation water (0.2 and 3.5 dS m-1, respectively, without and with salt stress), with four repetitions. SNP concentrations were applied weekly (via leaf), totaling three applications during the cycle. The variables analy... (Complete abstract click electronic access below) / Mestre

Living conditions of every organism are influenced by various factors at this time. Some of them have positive effect on organism, some negative. Basic condition for surviving is the ability to resist and adapt to changing metabolic and living conditions. Every single stress effect can lead to changes in metabolism but organisms have ability to develope sufficient mechanisms for stress response. Some of them are similar for all living organisms (enzyme production, endogenous primary stress metabolites) some of them are specific for certain organism or stress type. Cell stress response can be observed on different levels (proteomic, genomic, metabolomic). In proper conditions it can be used indrustrially. In this work, influences of various stress factors were studied. These factors were applied on selected organisms – carotenogenic yeast and plant materials. Yeast stress response was induced by osmotic and oxidation stress factors. Changes on proteomic level and in production of selected secondary metabolites were observed. Proteome was analyzed by 1D and 2D electrophoresis with subsequent analysis of proteins by mass spectrometry. Yeast strain Rhodotorula glutinis CCY 20-2-26 showed the best adaptation to stress factors, which was moreover accompanied by overproduction of carotenoids. This finding can be premise for next industrial production of carotenoids. In plant samples predominantly enzymes and metabolites involved in antioxidant response were studied.

>Magister Scientiae - MSc / Salt stress is a major abiotic stress that accounts for huge agricultural losses worldwide, which in turn threaten food security and sustainable agriculture. Salt triggers the excessive production of reactive oxygen species (ROS) which accumulate to levels that become toxic to plants, resulting in cell death and reduced plant growth. Part of the plant’s mechanisms to counteract ROS-induced cell death involves the scavenging ability of the antioxidant defense system to maintain redox homeostasis. Gallic acid (GA) is an antioxidant that has been shown to reduce salt-induced ROS in legume plants. However, its effects on wheat plants have not been elucidated. This study thus investigated the role of exogenous GA (250 μM) on the physiological responses and antioxidant system of wheat plants under salt stress (150 mM). In addition, this study also investigated how GA and salt stress influenced changes in the membrane proteome of wheat plants using LC-MS proteomic analysis. / 2022

Yes / The present study explored the mechanism of cytotoxic and genotoxic effects of AgNPs on a primary culture of mouse Sertoli cells in vitro. To understand the possible molecular mechanisms of testicular lesions following exposure to AgNPs, isolated Sertoli cells were exposed to 5, 10, or 15 μg/ml. DNA damage in the Comet assay and apoptosis in the TUNEL assay were evaluated. The mRNA expression of p53 and bcl-2 genes and their proteins involved in apoptosis was also investigated. The antioxidant status of treated Sertoli cells was determined by measuring superoxide dismutase (SOD-1), catalase (CAT), and glutathione peroxidase (GPX-1) and superoxide dismutase (SOD-1) using quantitative polymerase chain reaction (qPCR)qPCR. The superoxide anions were detected using the nitroblue tetrazolium (NBT) reduction assay. Results indicated that AgNP exposure causes increased oxidative stress levels. The activation of p53, repression of bcl-2 and reduction of endogenous antioxidant enzymes were also involved in these mechanistic pathways, leading to reduced cell numbers and cell detachment. / The Sponsorship of the Libyan Government of a PhD studentship to Khaled Habas