Browsing by Subject "Gastroenterology"
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Item Is an Enviormental Health Educational Intervention Sufficient to Change Behavior?: Perceptions from an Indigenous Lake Community in Guatemala(2006-12-01) Pezzia, Carla; Terrance Gratton; Sue Lurie; Norman TrieffPezzia, Carla. Is an environmental health educational intervention sufficient to change behavior?: Perceptions from an indigenous lake community in Guatemala. Master of Public Health (Environmental Health), December 2006, 46 pp., 6 tables, 1 illustration, references, 18 titles. Traditional environmental health practices focus on education and exposure prevention, but the division between the biophysico-chemical and social environment keeps them from always being sufficient; human ecology seeks to bridge this division. The second leading cause of mortality in Guatemala is gastrointestinal infections, and San Pedro, Guatemala, provides an opportunity to study these infections utilizing a human ecological approach. Morbidity data were collected from the local health center, observations noted systematically, and both residents and tourists were interviewed regarding their perceptions of the community’s environmental health. Results found that residents who had no contact with tourists stated that, for gastrointestinal infections due to refuse in the streets, education alone would not be sufficient to reduce this problem; most felt some type of government intervention would be necessary. It is recommended that public health specialists enjoy a human ecological approach and refer to the community when designing an appropriate intervention.Item The Effect of CsrA on Biofilm Development in Escherichia coli(2001-05-01) Jackson, Debra White; Julian Borejdo; Richard Easom; Jerry SimeckaJackson, Debra W., The Effect of CsrA on Biofilm Development in Escherichia coli. Doctor of Philosophy (Biomedical Sciences), May 2001, 127 pp., 2 tables, 15 illustrations, bibliography, 138 titles. CsrA, carbon storage regulator, is a small RNA-binding protein that acts as a global regulator and modulates specific mRNA stability in Escherichia coli. CsrA regulates central carbon metabolism in addition to flagella biogenesis. In this study, the phylogenetic distribution of csrA and its role in Escherichia coli biofilm development were examined. CsrA homologs were examined using Southern hybridization experiment and by analyzing existing sequencing data and was found to be widespread among eubacteria. CsrA was shown to be capable of acting as a genetic switch for biofilm formation and dispersal. A csrA mutant of E. coli was shown to increase biofilm formation and exhibit apparent pillars and channels characteristic of a mature biofilm. Over-expression of csrA completely inhibited biofilm formation in E. coli K-12 and decreased biofilm formation in related enteric pathogens. Induction of csrA expression from a multicopy plasmid caused dispersal of a pre-formed biofilm. Gene expression studies revealed that csrA expression is dynamically regulated during biofilm formation. Several outer-membrane factors and global regulators that have been implicated in biofilm formation were examined for effects on biofilm formation in a csrA mutant. Crystal violet adherence assays revealed that flagella and type I pili affect biofilm formation in a scrA mutant strain; however, colonic acid and curli fimbriae did not exhibit quantitative effects on biofilm formation in the csrA mutant, but the stationary phase sigma factor, RpoS, had no quantitative effect on csrA mutant biofilm formation. Therefore, a csrA mutant will form a biofilm in the absence of each of these outer-membrane factors and global regulatory factors of biofilm formation. The effects of csrA on biofilm formation were found to be mediated in part through its effects on intracellular glycogen metabolism. Thus the redirection of carbon flux, in response to environmental and/or physiological cues, is important for biofilm development.