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Description
The increase in obesity since the 1980's has been associated with fast-food consumption. In hopes that calorie labeling will be an effective tool to combat obesity, congress included a provision in the Patient Protection and Affordable Care Act of 2010 (ACA) that will require all restaurants with twenty or more locations to post calorie information for each menu item. Current research has provided mixed results regarding the effectiveness of calorie labeling, but overall seems to suggest that calorie labeling may only be effective among certain populations. In September, 2012 McDonald's began to post calorie labels on their menu boards before it was federally mandated under the ACA. This policy provided the opportunity to study the impact of calorie labeling on the purchasing behavior of McDonald's patrons. This cross-sectional study was designed to determine if self-perception of diet, self-perception of health, smoking, physical activity, fruit and vegetable intake, or knowledge of daily calorie requirements is associated with the likelihood of noticing or using calorie labels, or total calories purchased. In addition, relationships between noticing or using calorie labels with total calories purchased were also examined. Receipts and survey responses were collected from 330 participants who purchased food and beverage items from 27 different McDonald's locations within a 20 mile radius of downtown Phoenix, Arizona. Results indicated that only 16.1% of the sample reported using calorie labels, and those who reported using calorie labels purchased an average of 136 fewer calories. Multivariate analysis indicated there were no statistically significant relationships between self-perception of diet, self-perception of health, smoking, physical activity, fruit and vegetable intake, or knowledge of daily calorie requirements with the likelihood of noticing or using calorie labels, or total calories purchased. However, it is possible that the small sample size of participants using calorie labeling precluded any statistically significant relationships among these variables from emerging. Further research with larger sample sizes should be conducted, to investigate individual level factors that may be associated with use of calorie labeling.
ContributorsBrown, Alan (Author) / Ohri-Vachaspati, Punam (Thesis advisor) / Bruening, Meredith (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2013
Description
Like most other phototrophic organisms the cyanobacterium Synechocystis sp. PCC 6803 produces carotenoids. These pigments often bind to proteins and assume various functions in light harvesting, protection from reactive oxygen species (ROS) and protein stabilization. One hypothesis was that carotenoids bind to the surface (S-)layer protein. In this work the Synechocystis S-layer protein was identified as Sll1951 and the effect on the carotenoid composition of this prokaryote by disruption of sll1951 was studied. Loss of the S-layer, which was demonstrated by electron microscopy, did not result in loss of carotenoids or changes in the carotenoid profile of the mutant, which was shown by HPLC and protein analysis. Although Δsll1951 was more susceptible to osmotic stress than the wild type, the general viability of the mutant remained unaffected. In a different study a combination of mutants having single or multiple deletions of putative carotenoid cleavage dioxygenase (CCD) genes was created. CCDs are presumed to play a role in the breakdown of carotenoids or apo-carotenoids. The carotenoid profiles of the mutants that were grown under conditions of increased reactive oxygen species were analyzed by HPLC. Pigment lifetimes of all strains were estimated by 13C-labeling. Carotenoid composition and metabolism were similar in all strains leading to the conclusion that the deleted CCDs do not affect carotenoid turnover in Synechocystis. The putative CCDs either do not fulfill this function in cyanobacteria or alternative pathways for carotenoid degradation exist. Finally, slr0941, a gene of unknown function but a conserved genome position in many cyanobacteria downstream of the δ-carotene desaturase, was disrupted. Initially, the mutant strain was impaired in growth but displayed a rather normal carotenoid content and composition, but an apparent second-site mutation occurred infrequently that restored growth rates and caused an accumulation of carotenoid isomers not found in the wild type. Based on the obtained data a role of the slr0941 gene in carotenoid binding/positioning for isomerization and further conversion to mature carotenoids is suggested.
ContributorsTrautner, Christoph (Author) / Vermaas, Willem Fj (Thesis advisor) / Chandler, Douglas E. (Committee member) / Misra, Rajeev (Committee member) / Bingham, Scott E (Committee member) / Arizona State University (Publisher)
Created2011