Made available in DSpace on 2014-06-12T15:53:33Z (GMT). No. of bitstreams: 2 arquivo4862_1.pdf: 3670985 bytes, checksum: 96f13180974d4adc214a64fea85fc8fd (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / O efeito da atividade biológica in vitro dos extratos orgânicos e o ácido barbático purificado de Cladia aggregata foi avaliado sobre microrganismos patógenos e células cancerígenas. Os extratos orgânicos foram obtidos a partir de 50g do talo liquênico in natura, através de extrações por esgotamento a frio e a quente, obedecendo a série eluotrópica éter, clorofórmio e acetona. Os extratos etéreos apresentaram cromatografia em camada delgada (CCD) e líquida de alta eficiência (CLAE) com menor número de bandas e picos respectivamente com rendimento total de 1,690g para o extrato frio e 2,183g para a quente. O ácido barbático foi purificado a partir do extrato etéreo a quente, através de várias lavagens com clorofórmio, cuja concentração demonstrada na CLAE foi de aproximadamente 96%. A atividade antimicrobiana foi verificada através de screening em disco, biocromatograma e concentração mínima inibitória (CMI).O teste em disco foi feito contra bactérias Gram-positivas, Gram-negativas e fungo. O biocromatograma e a CMI apenas com Gram-positivas. Os discos de papel foram impregnados com 21&#956;L das soluções dos extratos, a uma concentração de 43mg/mL e, do ácido barbático purificado dissolvido em éter e água na mesma concentração. Os resultados demonstraram atividade contra Staphylococcus aureus e o ácido barbático purificado dissolvido em água apresentou o melhor halo de inibição, 13,5mm. Os resultados dos biocromatogramas dos extratos orgânicos e ácido barbático purificado contra S. aureus, apresentaram sinergismo entre as substâncias, verificando-se a presença de um único halo de inibição ao redor do cromatograma. O ácido barbático purificado foi submetido a diluições em 9 partes a 2mg/mL e a CMI contra S. aureus ficou entre 200 - 50&#956;g/mL. Para os testes citotóxicos foram usados o extrato etéreo a quente a 50; 25; 12,5 e 6,5 &#956;g/mL e o ácido barbático a 20; 10; 5 e 2,5 &#956;g/mL , obtidos conforme metodologia anterior contra as seguintes linhagens de células cancerígenas: Hep-2, NCI-H292 e KB. O extrato etéreo a quente inibiu o crescimento celular em 78; 72; 70 e 60% Hep-2; 63; 61; 36 e 42% NCI- H292; 80; 80; 52 e 47% KB com CI50: < 6,5 &#956;g/mL para Hep-2 e 6,5 12,5 &#956;g/mL para NCI- H292 e KB. O ácido barbático purificado inibiu Hep-2 em 61; 66; 54 e 49%; NCI H292 63,4; 61,1; 36,7 e 42%; KB 77; 71; 53 e 43%, com CI50: 2,5 - 5 &#956;g/mL para Hep-2 e KB e 5 &#956;g/mL para NCI- H292. Os resultados demonstraram que os extratos orgânicos e o ácido barbático purificado apresentaram atividade antimicrobiana frente a S. aureus e atividade citotóxica para as células cancerígenas testadas

Premise of research. Dust particles and pollen grains are similar in size. Dust deposition might therefore influence the pollination and reproduction of flowering plants. Little is known about such effects, however, despite more general interest in ecological effects of dust. Methodology. We used observational and experimental methods to explore whether dust generated by traffic on unpaved roads affects the amounts of pollen received and numbers of seeds produced by four species of native wildflowers in the western United States. Pivotal results. Flowers of Nuttall's larkspur (Delphinium nuttallianum), scarlet gilia (Ipomopsis aggregata), Lewis flax (Linumlewisii), and sulphur paintbrush (Castilleja sulphurea) growing 1-2mfrom a road received substantially more dust and less pollen than those growing 40-50 m away. We observed the same pattern when we transplanted individuals of the first two species into pots and placed pots near to compared with far from a road. Experimental "hand dusting" of scarlet gilia and Lewis flax plants also reduced stigma pollen loads to a degree that resembled the average effect of road proximity for those species. On the other hand, numbers of seeds per flower ("seed set") did not vary consistently for any species as a function of road proximity or hand-dusting treatment. Conclusions. Several mechanisms might contribute to the different effects of dust on pollen loads and seed set. Wediscuss four possible mechanisms, which we refer to as pollen excess, pollen quality, resource limitation, and compensatory herbivory. These mechanisms suggest avenues for further study of dust, pollination, and plant reproduction with this and other systems.

Individual differences in fecundity often serve as proxies for differences in overall fitness, especially when it is difficult to track the fate of an individual's offspring to reproductive maturity. Using fecundity may be biased, however, if density-dependent interactions between siblings affect survival and reproduction of offspring from high- and low-fecundity parents differently. To test for such density-dependent effects in plants, we sowed seeds of the wildflower Ipomopsis aggregata (scarlet gilia) to mimic partially overlapping seed shadows of pairs of plants, one of which produced twice as many seeds. We tested for differences in offspring success using a genetic marker to track offspring to flowering multiple years later. Without density dependence, the high-fecundity parent should produce twice as many surviving offspring. We also developed a model that considered the geometry of seed shadows and assumed limited survivors so that the number of juvenile recruits is proportional to the area. Rather than a ratio of 2:1 offspring success from high- versus low-fecundity parents, our model predicted a ratio of 1.42:1, which would translate into weaker selection. Empirical ratios of juvenile offspring and of flowers produced conformed well to the model's prediction. Extending the model shows how spatial relationships of parents and seed dispersal patterns modify inferences about relative fitness based solely on fecundity.

My dissertation research investigates the genetic architecture and evolutionary significance of physiological variation in two wildflower species, Ipomopsis aggregata and Arabidopsis thaliana. In particular, my work focuses on water use efficiency (WUE), a critical physiological trait that dictates plant growth and performance in resource-limited environments. I used a combination of quantitative trait loci (QTL) mapping, field selection experiments, and classic quantitative genetics to investigate 1) the genetic architecture of water use efficiency and flowering time, 2) patterns of natural selection on water use efficiency, flowering time, and other ecological traits in I. aggregata, and 3) additive genetic variation, genetic correlations, and selection on water use efficiency, flowering time, and plasticity to drought in Arabidopsis thaliana. Using an Ipomopsis aggregata genetic mapping population, I identified four QTL underlying WUE, three QTL-QTL epistatic interactions, and evidence for a possible QTL x cytoplasmic interaction affecting WUE. I found a similar genetic architecture underlying flowering time, with four main effect QTLs that all adjacently localized to the same linkage groups as WUE, and three QTL-QTL epistatic interactions, which occur between the same chromosome pairs as the WUE interactions. The combined main and interactive effects explain 35% and 40% of the phenotypic variation in WUE and flowering time, respectively. The adjacent localization suggests a possible role for the evolution of co-inheritance or, if the true QTL positions actually overlap, a possible role for pleiotropy underlying the phenotypic correlation between WUE and flowering time. Additionally, these results suggest epistasis is a significant factor affecting phenotypic variation in nature. In a reciprocal transplant and water addition experiment, I demonstrated variable natural selection on WUE, flowering time, and nectar production in I. aggregata across elevation/habitat and differential water availability. At low elevation in the water addition treatment, natural selection favors early flowering and greater nectar sugar concentration, while dry conditions favor high WUE and early flowering time. At high elevation, where the growing season is shorter and drier, selection favors early flowering regardless of water addition. These results suggest natural selection on ecophysiological and floral traits varies with resource availability (e.g. water availability and pollinator visitation). Using data from a glasshouse experiment involving a global panel of accessions of Arabidopsis thaliana, I demonstrated strong positive genetic correlation between WUE and flowering time, as well as selection for low WUE and early flowering under experimental season-ending drought. Finally, I found significant genetic variation in plasticity as well as selection favoring greater WUE plasticity under drought, indicating plasticity to drought is adaptive in A. thaliana. / text