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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.
1

The Genetics of Pigmentation in Corynebacterium poinsettiae ATCC 9682

Campbell, Alan L. (Alan Lee) 08 1900 (has links)
Corynebacterium poinsettiae mutant strains blocked in carotenoid biosynthesis were obtained by treatment with the mutagen N-methyl-N1-nitro-N-nitrosoguanidine. Additional carotenoid (Crt) mutant strains were obtained from a previous study conducted in our laboratory. Fifty-nine Crt mutants affected in carotenoid biosynthesis were examined by a normal phase high performance liquid chromatography (HPLC) system. Pigment extracts of Crt mutants and C. poinsettiae wild type strains were resolved by an isocratic system with hexane:acetone:dicholoromethane, 11.35:1.73:1.00 (by vol.) as the eluting solvent. In addition to the five major peaks, twelve minor peaks were observed in the wild type C. poinsettiae strain used in this study. Crt mutant and wild type strain peak heights were measured from the individual chromatograms and the peak height data set created was analyzed using the Statistical Analysis System program to perform a cluster analysis. The cluster analysis revealed five carotenoid mutant groups. Carotenoid pigments which accumulated or were absent in each of the cluster groups are reported. Cluster group 1 mutants (CrtA) are blocked in the dehydrogenase(s) which is(are) responsible for the dehydrogenations between phytoene and lycopene. Cluster group 2 mutants (CrtB) appear to be blocked at a second dehydrogenase specific for the dehydrogenation from C.p. 470 to C.p. 496. Cluster group 3 mutants (CrtC) are blocked at a cyclization step in the pathway which involves cyclization of C.p. 496 to C.p. 470 and which may cyclize C.p. 473 to C.p. 450. The genes CrtA and CrtB map only 0.5 map units from each other while CrtA and CrtC map 2.1 map units from one another. Mutants which accumulate end products but which lack certain precursors indicate a branched pathway for pigment biosynthesis exists in this organism. Media for the formation, fusion and regeneration of C. poinsettiae protoplasts are reported and a protocol for the use of these media in genetic crosses of strains blocked in carotenoid biosynthesis is described. While isolating antibiotic resistant mutants useful in genetic analyses, novobiocin resistant mutants were observed to have a distinctly different colony pigment phenotype as compared to the wild type strain. HPLC chromatograms of a novobiocin resistant strain showed a distinctly different carotenoid pigment profile. The results provide evidence for differential gene expression in the carotenoid biosynthetic pathway when these mutants are grown in the presence of novobiocin.
2

Seletividade de sulfentrazone e clomazone aplicados em pré-plantio de mudas pré-brotadas de cana-de-açúcar CTC 11 / Selectivity of sulfentrazone and clomazone when applied in the pre-planting stage for pre-sprouted seedlings of CTC11 sugarcane

Perez, Leonardo Lombardi 17 August 2017 (has links)
O manejo químico de plantas daninhas no sistema de plantio por mudas pré-brotadas de cana-de-açúcar, fundamenta a hipótese de que a cultura esteja mais suscetível à intoxicação pelos herbicidas nas aplicações em pré-plantio, devido as raízes das mudas serem transplantadas em contato direto com a solução do solo tratada com os herbicidas aplicados em pré-emergência. Portanto a pesquisa foi desenvolvido com dois objetivos: (1) avaliar a seletividade do herbicida sulfentrazone quando aplicado em área de plantio de cana-de-açúcar no sistema com mudas pré-brotadas com aplicação no pré-plantio utilizando cinco doses (200, 400, 800, 1600 e 3200 g i.a. ha-1); (2) avaliar a seletividade de doses crescentes de clomazone (270, 540, 1080, 2160, e 4320 g i.a. ha-1), quando aplicado em pré-plantio em mudas pré-brotadas (MPB). Os experimentos foram desenvolvidos na Usina São Martinho, próximo ao município de Motuca (SP), sob condições naturais de clima, no período de outubro de 2015 a setembro de 2016. O delineamento experimental foi em blocos ao acaso, com quatro repetições. Os herbicidas foram aplicados no dia anterior ao plantio das mudas pré-brotadas, onde foi utilizada a variedade CTC 11, que foram transplantadas nas parcelas, constituídas por 6 linhas de 10 m, espaçadas de 1,5 m. Foram feitas avaliações visuais com 15, 30, 60, 90 e 120 dias após a aplicação dos tratamentos (DAA), também utilizando-se uma escala visual com notas entre 0 e 100%. Nas avaliações quantitativas avaliou-se os parâmetros altura de plantas (cm), aos 30, 60, 90 e 120 DAA e perfilhamento das mudas aos 60, 90 e 120 DAA. Em todos os períodos avaliados foi utilizado o medidor de clorofila, marca SPAD. Aos 330 DAA, foi realizada a produtividade (t ha-1) integral das parcelas através do corte manual e posterior pesagem com auxílio de uma célula de carga, e foram coletados feixes com dez canas para realização dos parâmetros qualitativos (Brix, Pol, Pureza e ATR). Em ambos trabalhos, os dados de fitointoxicação e produtividade foram previamente transformados na regressão log logística, respeitando o princípio da normalidade dos dados, identificando a dose seletiva para a cultura. Concluiu-se que os herbicidas sulfentrazone (800 g i.a. ha-1), e clomazone (1080 g i.a. ha-1), que são doses comercialmente utilizadas no plantio convencional através de rebolos de cana-de-açúcar, apresentaram sintomas leves de fitointoxicação nas primeiras avaliações, mas com o crescimento e desenvolvimento das mudas, não apresentaram diferença de altura, perfilhamento e índice SPAD, como também na produtividade e características tecnológicas dos colmos não apresentando diferenças significativas. Portanto os herbicidas sulfentrazone e clomazone foram seletivos às mudas de cana-de-açúcar no sistema MPB quando aplicados em pré-plantio para a CTC 11. / The chemical management of plant pests in the planting system with pre-sprouted sugarcane seedlings substantiates the hypothesis that the crop is more susceptible to toxicity by herbicides in pre-planting applications, due to the roots of the seedlings being transferred in direct contact with the soil solution treated with the herbicides applied in the pre-emergence stage. Therefore, this work was prepared with two goals: (1) to assess the selectivity of the herbicide sulfentrazone when applied to a sugarcane planting area in the pre-sprouted seedlings system with application in the pre-planting stage using five rates (200, 400, 800, 1600 and 3200 g a.i. ha-1); (2) to assess the selectivity of growing rates of clomazone (270, 540, 1080, 2160 and 4320 g a.i. ha-1), when applied in the pre-planting stage for pre-sprouted seedlings. The experiments were developed in São Martinho sugar mills, next to the town of Motuca (SP), under natural weather conditions, in the period from October 2015 to September 2016. The experimental design was done in blocks at random, with four repetitions. The herbicides were applied on the day prior to the planting of the pre-sprouted seedlings, where the CTC 11 strain was used, which seedlings were transferred into parcels comprised of 6 lines of 10 m, spaced by 1.5 m. Visual assessments were made 15, 30, 60, 90 and 120 days after the treatment application (DAA), a visual grading scale between 0 and 100% was also used. In the quantitative assessments, the parameters for height of the plants (cm), at 30, 60, 90 and 120 DAA, and tillering at 60, 90 and 120 DAA, were evaluated. In all assessed periods, a direct reading was performed using the chlorophyll meter, SPAD brand. At 330 DAA, the entire productivity (t ha-1) of the parcels was assessed through the manual cut and later weighing with the aid of a load cell, and strips with ten sugarcanes were collected for the performance of qualitative parameters (Brix, Pol, Purity and ATR). In both works, the phytotoxicity and productivity data were previously converted by the log-logistic regression, observing the principle of data normalization, identifying the selective rates for the crop. It was found that herbicides sulfentrazone (800 g a.i ha-1), and clomazone (1080 g a.i. ha-1), which are rates commercially used in the conventional planting through sugarcane billets, presented slight symptoms of phytotoxicity in the first assessments, but with the growth and development of the seedlings, they did not show a difference in height, tillering, SPAD index, and in the yield; and the technological characteristics of the stalks did not present significant differences. Therefore, the herbicides sulfentrazone and clomazone were selective to the sugarcane seedlings in the pre-sprouted seedlings (MPB) system when applied in the pre-planting stage for CTC 11.
3

Seletividade de sulfentrazone e clomazone aplicados em pré-plantio de mudas pré-brotadas de cana-de-açúcar CTC 11 / Selectivity of sulfentrazone and clomazone when applied in the pre-planting stage for pre-sprouted seedlings of CTC11 sugarcane

Leonardo Lombardi Perez 17 August 2017 (has links)
O manejo químico de plantas daninhas no sistema de plantio por mudas pré-brotadas de cana-de-açúcar, fundamenta a hipótese de que a cultura esteja mais suscetível à intoxicação pelos herbicidas nas aplicações em pré-plantio, devido as raízes das mudas serem transplantadas em contato direto com a solução do solo tratada com os herbicidas aplicados em pré-emergência. Portanto a pesquisa foi desenvolvido com dois objetivos: (1) avaliar a seletividade do herbicida sulfentrazone quando aplicado em área de plantio de cana-de-açúcar no sistema com mudas pré-brotadas com aplicação no pré-plantio utilizando cinco doses (200, 400, 800, 1600 e 3200 g i.a. ha-1); (2) avaliar a seletividade de doses crescentes de clomazone (270, 540, 1080, 2160, e 4320 g i.a. ha-1), quando aplicado em pré-plantio em mudas pré-brotadas (MPB). Os experimentos foram desenvolvidos na Usina São Martinho, próximo ao município de Motuca (SP), sob condições naturais de clima, no período de outubro de 2015 a setembro de 2016. O delineamento experimental foi em blocos ao acaso, com quatro repetições. Os herbicidas foram aplicados no dia anterior ao plantio das mudas pré-brotadas, onde foi utilizada a variedade CTC 11, que foram transplantadas nas parcelas, constituídas por 6 linhas de 10 m, espaçadas de 1,5 m. Foram feitas avaliações visuais com 15, 30, 60, 90 e 120 dias após a aplicação dos tratamentos (DAA), também utilizando-se uma escala visual com notas entre 0 e 100%. Nas avaliações quantitativas avaliou-se os parâmetros altura de plantas (cm), aos 30, 60, 90 e 120 DAA e perfilhamento das mudas aos 60, 90 e 120 DAA. Em todos os períodos avaliados foi utilizado o medidor de clorofila, marca SPAD. Aos 330 DAA, foi realizada a produtividade (t ha-1) integral das parcelas através do corte manual e posterior pesagem com auxílio de uma célula de carga, e foram coletados feixes com dez canas para realização dos parâmetros qualitativos (Brix, Pol, Pureza e ATR). Em ambos trabalhos, os dados de fitointoxicação e produtividade foram previamente transformados na regressão log logística, respeitando o princípio da normalidade dos dados, identificando a dose seletiva para a cultura. Concluiu-se que os herbicidas sulfentrazone (800 g i.a. ha-1), e clomazone (1080 g i.a. ha-1), que são doses comercialmente utilizadas no plantio convencional através de rebolos de cana-de-açúcar, apresentaram sintomas leves de fitointoxicação nas primeiras avaliações, mas com o crescimento e desenvolvimento das mudas, não apresentaram diferença de altura, perfilhamento e índice SPAD, como também na produtividade e características tecnológicas dos colmos não apresentando diferenças significativas. Portanto os herbicidas sulfentrazone e clomazone foram seletivos às mudas de cana-de-açúcar no sistema MPB quando aplicados em pré-plantio para a CTC 11. / The chemical management of plant pests in the planting system with pre-sprouted sugarcane seedlings substantiates the hypothesis that the crop is more susceptible to toxicity by herbicides in pre-planting applications, due to the roots of the seedlings being transferred in direct contact with the soil solution treated with the herbicides applied in the pre-emergence stage. Therefore, this work was prepared with two goals: (1) to assess the selectivity of the herbicide sulfentrazone when applied to a sugarcane planting area in the pre-sprouted seedlings system with application in the pre-planting stage using five rates (200, 400, 800, 1600 and 3200 g a.i. ha-1); (2) to assess the selectivity of growing rates of clomazone (270, 540, 1080, 2160 and 4320 g a.i. ha-1), when applied in the pre-planting stage for pre-sprouted seedlings. The experiments were developed in São Martinho sugar mills, next to the town of Motuca (SP), under natural weather conditions, in the period from October 2015 to September 2016. The experimental design was done in blocks at random, with four repetitions. The herbicides were applied on the day prior to the planting of the pre-sprouted seedlings, where the CTC 11 strain was used, which seedlings were transferred into parcels comprised of 6 lines of 10 m, spaced by 1.5 m. Visual assessments were made 15, 30, 60, 90 and 120 days after the treatment application (DAA), a visual grading scale between 0 and 100% was also used. In the quantitative assessments, the parameters for height of the plants (cm), at 30, 60, 90 and 120 DAA, and tillering at 60, 90 and 120 DAA, were evaluated. In all assessed periods, a direct reading was performed using the chlorophyll meter, SPAD brand. At 330 DAA, the entire productivity (t ha-1) of the parcels was assessed through the manual cut and later weighing with the aid of a load cell, and strips with ten sugarcanes were collected for the performance of qualitative parameters (Brix, Pol, Purity and ATR). In both works, the phytotoxicity and productivity data were previously converted by the log-logistic regression, observing the principle of data normalization, identifying the selective rates for the crop. It was found that herbicides sulfentrazone (800 g a.i ha-1), and clomazone (1080 g a.i. ha-1), which are rates commercially used in the conventional planting through sugarcane billets, presented slight symptoms of phytotoxicity in the first assessments, but with the growth and development of the seedlings, they did not show a difference in height, tillering, SPAD index, and in the yield; and the technological characteristics of the stalks did not present significant differences. Therefore, the herbicides sulfentrazone and clomazone were selective to the sugarcane seedlings in the pre-sprouted seedlings (MPB) system when applied in the pre-planting stage for CTC 11.
4

The labyrinth of protein classification: a pipeline forselection and classification of biological data

Pelosi, Benedetta January 2022 (has links)
Recent progress in fundamental biological sciences and medicine has considerably increased the quantity ofdata that can be studied and processed. The main limitation now is not retrieving data, but rather extractinguseful biological insights from the large datasets accumulated. More recent advances have provided detailedhigh-density data regarding metabolism (metabolomics) and protein expression (proteomics). Clearly, no single analytic methods, can provide a comprehensive understanding. Rather, the ability to link available datatogether in a coherent manner is required to obtain a complete view. The improving application of MachineLearning (ML) techniques provides the means to make continuous progress in processing complex data sets.A brief discussion is offered on the advantages of ML, the state-of-the-art in Deep Learning (DL) for proteinpredictions and the importance of ML in biological data processing. Noise stemming from incorrect classification or arbitrary/ambiguous labelling of data may arise when ML techniques are applied to large datasets. Furthermore, the stochasticity of biological systems needs to be considered for correctly evaluating theoutputs. Here we show the potential of a workflow to respond biological questions taking into consideration aperturbation of the biological data.  For controlling the applicability of models and maximizing the predictivity, in silico filtering schemescan usefully be applied as an “Ockham’s razor” before using any ML technique. After reviewing differentDL approaches for protein prediction purposes, this work shows that a computational approach in filteringsteps is a valuable tool for proteins classification when biological features are not fully annotated or reviewed.The in silico approach has identified putative proline transporters in fungi and plants as well as carotenoidbiosynthetic gene products in the plant family Brassicaceae. The proposed method is suitable for extractingfeatures of classification and then maximizing the use of a DL approach.
5

Naturally occurring variation in the promoter of the chromoplast-specific Cyc-B gene in tomato can be used to modulate levels of ß-carotene in ripe tomato fruit

Orchard, Caleb January 2014 (has links)
No description available.

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