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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

An investigation of the antioxidant properties of some culinary herbs and their potential application in a cosmetic preparation

Naidoo, Nareshini January 2007 (has links)
Thesis (M.Tech.: Food Technology)-Dept. of Biotechnology, Durban University of Technology, 2007 xv, 122 leaves / Several herbs are well known for their nutritional applications. The reported study tested some herbs for their efficacy as antioxidants. The herbs and combinations thereof were analyzed for antioxidant activity using two comparative methods: the beta-carotene bleaching method and through measurement by the Rancimat apparatus. The efficacy of the antioxidants was also tested in a cosmetic base cream. The concentration of the natural antioxidant vitamins, such as vitamin C, vitamin E and beta-carotene was determined by analytical methods. The methods used for analysis provided adequate results for interpretation. All herbs exhibited antioxidant activity, at comparable levels. The two methods used for analysis showed variable results, as previous researchers have shown. In terms of antioxidant potency, the herbs were ranked as follows: fenugreek > coriander > oregano > sage (beta-carotene bleaching method), oregano > sage > coriander > fenugreek (Rancimat method). Oregano and sage were good synergists, when combinations of herbs were used. Fenugreek, unlike the other herbs under investigation, is a prooxidant when used at higher concentrations. A direct relationship was observed between the concentration of herbs and antioxidant potency for sage, oregano and coriander. Fenugreek which is prooxidant at higher concentrations, should be used as an antioxidant independently rather than a synergist. This was the most important finding in the reported study. Similar antioxidant activities of the herbs were observed in the base cosmetic formulation. The reported study has provided an adequate base for further quantitative research into the innovative topic of antioxidants.
112

Anti-HIV activity of selected South African medicinal plants

Hurinanthan, Vashka 17 September 2013 (has links)
Submitted in complete fulfilment for the Degree of Doctorate of Technology (Biotechnology)--Durban University of Technology, 2013. / South Africa has the largest number of people infected with HIV/AIDS. It also has more than 30 000 species of plants and many of these have a long tradition of medicinal use. It is highly likely that the treatment for HIV will come from this traditional knowledge. The need for effective preventative and therapeutic agents for HIV remains an urgent global priority. The aim of this study was to screen selected South African medicinal plants for anti-HIV activity and to identify and characterise an active compound from a plant that can be used for HIV treatment. The aqueous and methanolic extracts of the roots, leaves, flowers and stems of thirty eight plant species (108 extracts) were screened for anti-HIV activity. The plants which had anti-HIV activity were further screened for anti-reverse transcriptase activity. Thirty-two extracts exhibited varying degrees of anti-HIV activity. Cleome monophylla, Dichrostachys cinerea and Leonotis leonurus aqueous leaf extracts had anti-HIV-1 reverse transcriptase activity. The aqueous extracts of D. cinerea showed the best anti-HIV activity with a Selectivity Index of 43.5 and significant anti-HIV-1 reverse transcriptase activity. Crude phytochemical screening of D. cinerea showed that it had tannins, saponins, flavonoids and alkaloids but did not contain any phlobatannins, terpenoids, steroids or phenols. D. cinerea displayed a high degree of free radical scavenging activity with an IC50 of 25 μg/ml, therefore the anti-HIV activity could be attributed to the flavonoids present in the plant. Bio-guided fractionation was used to isolate and purify the active compound from the D. cinerea extract. Compounds were isolated by thin layer chromatography and were tested for anti-HIV-1 and anti-reverse transcriptase activity. From these results the active compound was identified, and purified using preparative TLC. The active compound was characterised by High Performance Liquid Chromatography, Ultraviolet-visible spectrophotometry, and Ultra Performance liquid chromatography coupled to MS/MS. Structural elucidation was performed using Nuclear Magnetic Resonance. From these results, it was deduced that the compound isolated from D. cinerea was a catechin. In this study we show that the catechins present in D. cinerea are responsible for the anti- HIV-I activity and inhibits the reverse transcriptase activity which is a key factor in the progression of HIV. Potentially, these results can be used to develop a new drug for the treatment of HIV or as a cost effective therapeutic agent in treating HIV-infected individuals with oxidative stress. / National Research Foundation
113

A contribui??o da biotecnologia vegetal para o desenvolvimento da cajucultura familiar no munic?pio de Serra do Mel (RN)

C?mara, Marianne de M?lo Arruda 27 February 2009 (has links)
Made available in DSpace on 2014-12-17T15:54:52Z (GMT). No. of bitstreams: 1 MarianneMAC.pdf: 690557 bytes, checksum: b90b415abf3acc2f75d29ad4843a4cc8 (MD5) Previous issue date: 2009-02-27 / This work focuses the familiar cajuculture at Serra of Mel (RN) that presents a geographic and climatic structure favourable to the development of the cajuculture; the interaction between the ambient factors and agriculture in the region provides a propitious environment to the culture of the cashew; the objective of present work was associate ambient, economic, social and cultural factors of this municipy with the possibility of a sustainable agriculture associated with the vegetal biotechnology / Este trabalho enfoca a cajucultura familiar no munic?pio de Serra do Mel (RN), o qual apresenta uma estrutura geogr?fica e clim?tica favor?vel ? cajucultura; a intera??o entre os fatores ambientais e a agricultura na regi?o proporciona um ambiente prop?cio ao cultivo do cajueiro; buscou-se com o presente trabalho associar os fatores ambientais, econ?micos, sociais e culturais do munic?pio com a possibilidade de desenvolvimento de uma agricultura sustent?vel integrada ? biotecnologia vegetal
114

Diretrizes para conserva??o da esp?cie Mimosa Caesalpiniifolia Benth., Maca?ba-RN / Guidelines to conservation of Mimosa caesalpiniifolia Benth. specie in Maca?ba - RN, Brazil

Souza, Clarice Sales Moraes de 10 February 2012 (has links)
Made available in DSpace on 2014-12-17T15:54:58Z (GMT). No. of bitstreams: 1 ClariceSMS_DISSERT.pdf: 2195559 bytes, checksum: 0d9f33a9215348cab59927e163f16ee6 (MD5) Previous issue date: 2012-02-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / About 40% of the earth is occupied by tropical and subtropical forests, including 42% of dry forests, where there is Caatinga Bioma, contemplating tree forests and shrubs, with xerophytic characteristics. Study and conservations of Caatinga biologic diversity is one of the greatest challenges of Brazilian science because those are, proportionally, the less studied among natural areas, with most of the scientific effort centered in very few points around the main cities in the area and also because it is the less protected natural Brazilian area. The environmental degradation is constantly increasing and has its rhythm accelerated by the men appropriation to meet or not their own needs. Therefore, species conservation should be based in three principles: the use of natural resources by present generation, waste prevention and use of the natural resources to benefit the majority of the citizens. Among the strategies to species conservation, we can mention the ex situ conservation , in which the conservation of genetic resources may be realized outside of the natural environment in which the species occur, and in situ conservation , or, in other words, in the places where the species occur. In ex situ conservation, the germplasm collections are maintained in the field and/or in laboratories (conservation chambers), and this mainly conserves intraspecific diversity (genetic variance), the ex situ collections are continuously enriched by collection activities, introduction and germplasm interchange; the in situ conservation preserving ecosystems and habitats, maintaining and recovering native population of species of interest. So, the objective of this paper is the search for strategies to the conservation of Mimosa caesalpiniifolia B. (sabi?) using instruments of environmental perception and plant biotechnology, as mechanisms of in situ and ex situ conservation. To environmental perception, were realized open, semi-structured and qualitative interviews. The questions included socioeconomic data and knowledge of Sabi? specie. To plant biotechnology, Sabi? seed collection were realized in different location to formation of a germplasm bank. The specie micropropagation was made from nodal segment of plants from the matrizeiro. About the knowledge of rural populations and the use of Sabi? plant, some preferences occurred from speeches that the plant possesses a firm wood, not attacked by termites, legalized for exploration by the Brazilian environmental organ (IBAMA), and is a native specie. This research found the rural population has knowledge about Sabi? specie and the natural resources are exhausting. The proposal that the rural community brought was the donation of the Sabi? specie seeding initiating on the rain season, in which the seeding would be plated between the lots, in individual plantations. To the formation of a matrix bank, plant biothecnology brought answers favorable to Sabi? specie seeding, with the formation of multiple shoots / Cerca de 40% do globo terrestre est? ocupado pelas florestas tropicais e subtropicais, entre as quais 42% s?o compreendidas pelas florestas secas, onde se inclui o Bioma Caatinga, contemplando com floresta arb?rea ou arbustiva, de caracter?sticas xerof?ticas. O estudo e a conserva??o da diversidade biol?gica da Caatinga ? um dos maiores desafios da ci?ncia brasileira, pois, estas s?o proporcionalmente as menos estudadas entre as ?reas naturais, com grande parte do esfor?o cient?fico concentrado em alguns poucos pontos em torno das principais cidades da regi?o, e tamb?m por ser a regi?o natural brasileira menos protegida. A degrada??o do meio ambiente vem aumentando cada vez mais, tendo, ao mesmo tempo, seu ritmo acelerado em decorr?ncia da sua apropria??o cada vez maior pelo homem, a fim de suprir suas necessidades imediatas ou n?o. Assim a conserva??o de esp?cies deveria basear-se em tr?s princ?pios: os usos dos recursos naturais pela gera??o presente, a preven??o de desperd?cio e o uso dos recursos naturais para benef?cio da maioria dos cidad?os. Dentre as estrat?gias para conserva??o de esp?cies, podemos citar a conserva??o ex situ , na qual a conserva??o dos recursos gen?ticos pode ser realizada fora do ambiente de ocorr?ncia natural das esp?cies e conserva??o in situ , ou seja, nos locais de ocorr?ncia das esp?cies. Na conserva??o ex situ as cole??es de germoplasma s?o mantidas no campo e/ou laborat?rios (c?maras de conserva??o), e esta trata particularmente de conservar diversidade intraespec?fica (variabilidade gen?tica), as cole??es ex situ s?o continuamente enriquecidas por atividades de coleta, introdu??o e interc?mbio de germoplasma, j? a conserva??o in situ conservam-se ecossistemas e habitats, mantendo e recuperando popula??es nativas de esp?cies de interesse. Assim, o objetivo desta pesquisa ? a busca de estrat?gias para conserva??o de Mimosa caesalpiniifolia B. (sabi?) utilizando instrumentos de percep??o ambiental e biotecnologia vegetal, como mecanismos de conserva??o in situ e ex situ. Para a percep??o ambiental, realizamos entrevistas abertas, semi-estruturadas e de forma qualitativa. As perguntas eram compostas por dados socioecon?micos e conhecimentos da esp?cie Sabi?. Para a biotecnologia vegetal, coletas de sementes de Sabi? foram realizadas em distintos locais para a forma??o de um banco de germoplasma. A micropropaga??o da esp?cie foi a partir de segmentos nodais de plantas provindas do matrizeiro. Com rela??o ao conhecimento das popula??es rurais ao uso da planta Sabi? ocorreram prefer?ncias a partir dos discursos que a planta possui uma madeira firma, n?o ? atacada por cupim, ? legalizada para a explora??o pelo ?rg?o ambiental federal (IBAMA), e ? uma esp?cie da regi?o. A pesquisa caracterizou que a popula??o rural possui conhecimentos sobre a esp?cie Sabi? e que percebem que os recursos naturais est?o se exaurindo. A proposta que a comunidade rural sup?s foi ? doa??o de mudas da esp?cie Sabi? a partir do per?odo das chuvas, em que as mudas seriam plantadas na divis?o entre os lotes, em plantios individuais. Para a forma??o de um banco de matrizes, a biotecnologia vegetal trouxe respostas favor?veis na produ??o de mudas da esp?cie Sabi?, com a forma??o de brota??es e mudas vigorosas
115

Clonagem do cDNA que codifica a enzima UDP-glicose pirofosforilase de batata (Solanum tuberosum L.). / Cloning of cdna encoding potato (Solanum tuberosum L.) udp-glucose pyrophosphorylase.

Gunta Gutmanis 30 January 2004 (has links)
A biotecnologia está revolucionando a atividade humana nas mais diversas áreas. No setor florestal, as novas tecnologias como transgenia, genômica, proteômica e bioinformática, estão sendo rapidamente incorporadas. A associação dessas tecnologias aos programas de melhoramento convencional de árvores pode acelerar o processo de obtenção de árvores com características específicas da madeira para a indústria de papel e celulose. UDP–glicose pirofosforilase (UGPase, EC 2.7.7.9) é uma enzima chave na produção de UDP-glicose, intermediário na interconversão de carboidratos envolvidos em várias funções metabólicas, como síntese de sacarose e de celulose. No presente trabalho, foi clonado o cDNA que codifica a UGPase. Este cDNA foi sintetizado por meio de RT-PCR utilizando-se mRNA extraído de tubérculo de batata (Solanum tuberosum L.). Os primers específicos para a ORF do gene da UGPase foram definidos com base em seqüências conservadas entre genes ortólogos, já disponíveis em bancos de dados. O cDNA foi clonado no vetor pENTR-D TOPO e inserido, por meio de transformação química, em células competentes de Escherichia coli. O DNA plasmidial foi purificado e após seu sequenciamento, a presença de um inserto de 1402 pb foi confirmada. O alinhamento da seqüência deduzida de aminoácidos com outras UGPases revelou alta homologia a UGPases de batata e de outras espécies vegetais. Na seqüência do cDNA clonado foram identificados sítios de N-glicosilação, resíduos lisina e motivos conservados que possivelmente estão relacionados tanto com a capacidade de ligação ao substrato, como com a atividade catalítica da enzima. Também foi realizada uma análise de Southern blot para confirmar a presença deste gene no DNA genômico de batata e de eucalipto (Eucalyptus grandis). Posteriormente, o cDNA clonado será utilizado na avaliação do impacto de sua superexpressão na biossíntese de celulose e hemiceluloses e no desenvolvimento de plantas de fumo (Nicotiana tabacum) e de eucalipto. / Biotechnology is revolutionazing human activity in several fields. In forestry, new technologies like transgenies, genomics, proteomics and bioinformatics have been quickly consolidated. Assossiating these technologies with conventional forestry breeding will accelerate the process of obtaining new trees with specific wood properties for the paper and pulp industry. UDP-glucose pyrophosphorylase (UGPase, EC 2.7.7.9) is a key enzyme producing UDP-glucose, an important intermediate in carbohydrate interconversion involved in various metabolic processes like sucrose and cellulose synthesis. In this work, it was cloned the cDNA that encodes UGPase. This cDNA was synthetized through RT-PCR using RNA extracted from potato (Solanum tuberosum L.) tuber. The UGPase primers were designed based on the conserved sequences of hortologous genes, already available in public data banks. The cDNA was cloned into pENTR-D TOPO vector and introduced into Escherichia coli competent cells, by chemically transforming. The plasmid DNA was purified and the insert PCR amplified. The presence of 1402 bp insert was confirmed after sequencing. The alignment of the derived amino acids sequence with other UGPases revealed high homology to UGPases from potato and other plant species. Along the cDNA sequence N-glicolisation sites, Lysyl residues and conserved domain were identified, which probably are involved in substrate binding capacity, as well as catalytic ativity of the enzyme. Southern blot analysis was carried to confirm the presence of this gene in potato and eucalypt (Eucalyptus grandis) genomic DNA. The cloned cDNA will be used to evaluate the impact of overexpression on celullose and hemicelluloses biosynthesis and in the tobacco (Nicotiana tabacum) and eucalypt plant development.
116

Production and engineering of a xyloglucan endo-transglycosylase from Populus tremula x tremuloides

Henriksson, Maria January 2007 (has links)
The aim of this work was to develop a production process for the enzyme xyloglucan endo-transglycosylase from Populus tremula x tremuloides (PttXET16-34). The natural transglycosylating activity of this enzyme has previously been employed in a XET-Technology. This chemo enzymatic method is useful for biomimetic modification of cellulose surfaces and holds great potential for industrial applications. Thus, it requires that the XET-enzyme can be produced in larger scale. This work also shows how the wildtype PttXET16-34 was modified into a glycosynthase. By mutation of the catalytic nucleophile into an alanine, glycine or serine residue, enzymes capable of synthesising defined xyloglucan fragments were obtained. These defined compounds are very valuable for further detailed studies of xyloglucan active-enzymes, but are also useful in molecular studies of the structurally important xyloglucan-cellulose interaction. A heterologous production system for PttXET16-34 was previously developed in the methylotrophic yeast Pichia pastoris. A methanol-limited fed-batch process was also previously established, but the yield of active XET was low due to proteolysis problems and low productivity. Therefore, two alternative fed-batch techniques were investigated for the production of PttXET16-34: a temperature-limited fed-batch (TLFB) and an oxygen-limited high-pressure fed-batch (OLHPFB). For the initial recovery of XET after the fermentation process, two different downstream processes were investigated: expanded bed adsorption (EBA) and cross-flow filtration (CFF). / <p>QC 20101108</p>
117

Anticancer activity of ceratotheca triloba

Naicker, Leeann January 2016 (has links)
Submitted in complete fulfillment for the Degree of Doctorate of Philosophy in Biotechnology, Durban University of Technology, Durban, South Africa, 2016. / Plants have provided a source of medicine from the beginning of human history and are the core of modern medicine. Moreover, plant based drug discovery has led to the development of various anticancer drugs (such as vincristine, vinblastine, etoposide, paclitaxel, camptothecin, topotecan and irinotecan). The use of botanical, phytochemical, biological and molecular techniques have facilitated the discovery of anthraquinones from Ceratotheca triloba that can inhibit the human topoisomerase II enzyme (target for anticancer drugs) and kill cancer cells. However, the C. triloba plant has not been extensively studied for its anticancer activity. Therefore, the aim of this study was to further investigate the anticancer activity of C. triloba and determine the classes of compounds that contributed towards its activity. In this study the leaf and root extracts were prepared by using hexane, DCM, hexane: DCM (1:1), methanol and/or water. These extracts were examined for their growth inhibitory potential on three cancer cell lines (A375 [melanoma], MDA-MB-231[breast] and WHCO1 [esophageal]) by using the MTT assay. Then, different mobile phases were prepared for optimizing the separation of the compounds of the active extract by TLC. Column chromatography was performed with the active extract by using five mobile phases (hexane : DCM [60 : 40, 40 : 60], DCM, DCM : ethyl acetate [90 : 10, 70 : 30, 60 : 40, 50 : 50, 50 : 60, 30: 60, 20 : 80], ethyl acetate and ethyl acetate: methanol [80 : 20, 70 : 30, 50 : 50]). The fractions collected from the column were examined for their growth inhibitory potential on two melanoma cell lines (A375 and UACC-62). The IC50 and TGI (total growth inhibition) values of the active fractions were determined. Also, the apoptosis inducing effects of the active fractions and standards (camptothecin and doxorubicin) were determined by using flow cytometer based assays (FITC annexin assay, PE active caspase 3 assay and BD MitoScreen assay). Subsequently, the chemical structures of the compounds that contributed towards the activity of these fractions were obtained by EI-LC-MS analysis. The results demonstrated that the hexane root extract exhibited the best percentage of growth inhibition (%GI) on all three cancer cell lines. The separation of the compounds of the hexane root extract was optimized on TLC plates by using different ratios of hexane and DCM. Column chromatography allowed for fractionation of this extract. Purified compounds were not obtained due to co-elution. Further research would have to be conducted to obtain purified compounds. This may involve the use of mini-column chromatography and PTLC. Overall a total of ten combined fractions were collected from the column. Four of these fractions (F2, F4, F5 and F8) displayed a high %GI on the A375 and UACC-62 cell lines. Moreover, fraction F4 was the most active fraction as it had the lowest IC50 (0.70 µg.ml-1 [A375] and 0.39 µg.ml-1 [UACC-62]) and TGI (12.50 µg.ml-1[A375] and 25 µg.ml-1 [UACC-62]) values in comparison to the other fractions. All four fractions induced depolarization of the mitochondria membrane potential (ΔΨ), caspase 3 activation, early apoptosis (phospholipid phosphatidylserine exposure) and/or late apoptosis in the melanoma cells. The results also revealed that fraction F4 (25 µg.ml-1) induced depolarization of the ΔΨ in a higher percentage of A375 (78.11%) and UACC-62 (87.4%) cells than the other fractions and standards. This fraction also induced caspase 3 activation in a high percentage of A375 (90.56%) and UACC-62 (96.78%) cells. Therefore fraction F4 was also the most active fraction in terms of apoptosis activity. Based on our results and literature findings we can deduce that the active fractions induced the intrinsic or extrinsic (type II) apoptosis pathway in the melanoma cells. Six classes of compounds were identified from the four active fractions. These were: benzothiophenones, benzopyranones, naphthoquinones, anthraquinones, androstanes and quinazolines. In conclusion, this is the first study that evaluated the growth inhibition potential of the leaf and root extracts of C. triloba on a panel of cancer cells. This research indicated that the hexane root extract displayed the best levels of cell growth inhibition. The active constituents of this extract were isolated into four fractions which elicited apoptosis inducing effects that promoted the extrinsic (type II) or intrinsic apoptosis pathway in the melanoma cells. Furthermore, fraction F4 contained the most active compounds from C. triloba as it had the lowest IC50 and TGI values (in comparison to the other fractions) and induced depolarization of the ΔΨ in the highest percentage of melanoma cells. It was confirmed that six classes of compounds were accountable for the anticancer activity of these fractions. Thus, the C. triloba plant is a rich source of anticancer compounds. / D
118

Modeling of plant in vitro cultures – overview and estimation of biotechnological processes

Maschke, Rüdiger W., Geipel, Katja, Bley, Thomas 25 January 2017 (has links) (PDF)
Plant cell and tissue cultivations are of growing interest for the production of structurally complex and expensive plant-derived products, especially in pharmaceutical production. Problems with up-scaling, low yields and high-priced process conditions result in an increased demand for models to provide comprehension, simulation, and optimization of production processes. In the last 25 years, many models have evolved in plant biotechnology; the majority of them are specialized models for a few selected products or nutritional conditions. In this article we review, delineate, and discuss the concepts and characteristics of the most commonly used models. Therefore, the authors focus on models for plant suspension and submerged hairy root cultures. The article includes a short overview of modeling and mathematics and integrated parameters, as well as the application scope for each model. The review is meant to help researchers better understand and utilize the numerous models published for plant cultures, and to select the most suitable model for their purposes.
119

Aspectos fisiológicos, bioquímicos e análise proteômica comparativa durante a maturação, germinação e conversão em plantas de embriões de Ocotea catharinensis Mez. (Lauraceae). / Physiological, biochemical aspects and comparative proteomic during maturation, germination and seedling conversion of Ocotea catharinensis Mez. (Lauraceae).

Dias, Leonardo Lucas Carnevalli 16 April 2009 (has links)
A semelhança entre os eventos da embriogênese zigótica e somática permite que sejam estabelecidos parâmetros para o acompanhamento destes dois processos. Neste trabalho foi estudada a embriogênese somática em Ocotea catharinensis, nas fases de maturação e germinação, além do processo germinativo da semente zigótica, avaliando-se parâmetros bioquímicos, e a expressão diferencial de proteínas. O tratamento com ABA + PEG em culturas de embriões somáticos apresentou variações semelhantes a apresentadas por embriões zigóticos no estádio de maturação. Não se observou a germinação de embriões somáticos, contudo verificou-se que a desidratação prévia promoveu importantes alterações bioquímicas. Durante a germinação, não se observou à síntese de novas proteínas no embrião zigótico. Os estudos proteômicos no desenvolvimento da semente permitiram a seleção de polipeptídios, marcadores estádio-específicos. Os resultados obtidos possibilitam a otimização e melhor entendimento das etapas da embriogênese somática, em espécies com sementes recalcitrantes, como O. catharinensis. / The great similarity among the events of zygotic and somatic embryogenesis allows the establishment of parameters for accompaniment of these processes. In the present work it was studied the somatic embryogenesis in Ocotea catharinensis, in the maturation and germination phases, and the zygotic embryogenesis. The biochemical parameters and differential expression of proteins were evaluated: The treatment with ABA + PEG presented similar variations for zygotic embryos in the maturation stage. The germination was not observed for somatic embryos; however, it was verified that the previous dehydration promoted important biochemical alterations. With relation to the zygotic embryo, throughout the germination process, the synthesis of new proteins was not observed. The proteomic studies carried out throughout seed development, allowed the selection of polypeptides with differential expression. The results obtained open perspectives for the methodology optimization of the somatic embryogenesis, for species with recalcitrant seeds, like O. catharinensis.
120

Mapeamento de QTL (Quantitative Trait Loci) associados à resistência do maracujá-doce à bacteriose / QTL mapping related to resistance of sweet passion fruit to bacterial blight

Braga, Marcelo Fideles 07 July 2011 (has links)
O maracujá-doce (Passiflora alata Curtis) é uma espécie nativa no Brasil. Seu cultivo tem crescido nos últimos anos devido a sua valorização no mercado in natura e seus usos na fitoterapia. Entretanto, os cultivos comerciais enfrentam problemas devido a ocorrência da bacteriose (Xanthomonas axonopodis pv. passiflorae). O patógeno é endêmico no país, apresentando considerável variabilidade genética em suas populações naturais. Este trabalho teve como objetivo identificar QTL relacionados à resistência de P. alata à bacteriose em uma população F1 segregante oriunda do cruzamento entre acessos não endogâmicos. Foram avaliados os caracteres: área total da folha (TA), idade de queda da folha inoculada (IK), área total da lesão foliar (LA), área de clorose foliar (CA) e área da necrose foliar (NEA). Apenas um dos isolados apresentou diferenças de severidade em relação aos demais, sendo o menos agressivo (PA8-2). A inoculação do isolado M-129 mostrou que há variação significativa na resposta da população ao patógeno, sendo possível a identificação de genótipos transgressivos. A herdabilidade dos caracteres variou de 45% a 71%%. Foi construído um mapa de ligação integrado com 1.786 cM e uma densidade média de 4,5 cM. A análise de marcas individuais indicou a associação de 51 marcas aos fenótipos avaliados. O mapeamento de QTL, realizado por intervalo composto e utilizando uma estratégia diferenciada para populações F1 segregantes, identificou regiões associadas a 26 QTL para os cinco caracteres avaliados, sendo 16 deles referentes à LA, CA e NEA. A variação fenotípica explicada individualmente pelos marcadores variou de 0,8% a 16,7%. Sugere-se que a resistência à bacteriose é quantitativa, com predominância de efeitos genéticos aditivos. / The sweet passion fruit (Passiflora alata Curtis) is a specie native to Brazil. Its cultivation has increased in recent years due to its market valuation in natura and their uses in herbal medicine. However, crops are facing problems due to the occurrence of bacterial blight (Xanthomonas axonopodis pv. passiflorae). The pathogen is endemic in the country, with considerable genetic variability in their natural populations. This study aimed to identify QTL related to resistance of P. alata to bacterial blight in an F1 segregant population from the cross between outbred accessions. Five traits were evaluated: total area of the leaf (TA), age of inoculated leaf fall (IK), area of the leaf´s lesion (LA), area of the leaf´s chlorosis (CA) and area of the leaf´s necrosis (NEA). Only one of the isolates showed differences in severity in relation to others, being the least aggressive (PA8-2). The inoculation of the isolate M-129 showed significant variation in population response to the pathogen, making it possible to identify transgressive genotypes. The heritability of characters ranged from 45% to 71%. An integrated linkage map was constructed, with a length of 1,786 cM and an average density of 4.5 cM. The analysis of individual marks indicated the association of 51 markers to phenotypes. The QTL mapping was performed using composite interval and a special strategy for segregating F1 populations, identified 26 regions associated with QTL for the five traits, 16 of them related to LA, CA and NEA. The phenotypic variation explained by individual markers ranged from 0,8% to 16,7%. It is suggested that the resistance to bacterial blight is quantitative, with a predominance of additive genetic effects.

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