Cells of an obligately psychrophilic marine bacterium, Vibrio marinus, strain MP-1, were grown at 4 C and 15 C and studied for possible physiological differences. No differences were noted in sugar fermentation or temperature-shift growth studies; in both cases adequate nutrients were available. Some differences were noted in viability retention and manometric studies; adequate nutrients were not available. Fifteen C cells were more heat stable than 4 C cells. Fifteen C cells also utilized glucose at a higher rate than 4 C cells. These differences were attributed to differences in intra-cellular organization. The results indicated that in order to correlate laboratory results with in situ conditions, marine microorganisms should be studied when grown at the temperature of their natural habitat and without an abundance of nutrients. / Graduation date: 1966

Vibrio vulnificus (Vv) and V. parahaemolyticus (Vp) are gram negative, halophilic bacteria that occur naturally in estuarine waters of Galveston Bay. Both bacteria have the potential to cause infections in humans either via consumption or direct contact. Finfish are a potential vector for these bacteria. Previous work by Brinkmeyer determined that these bacteria are present on the benthic dwelling catfish, Ariopsis felis and Bagre marinus, using a conventional microbial method. The present work focused on using Quantitative Polymerase Chain Reaction (QPCR) and Terminal Restriction Fragment Length Polymorphism (T-RFLP) to not only determine presence of these bacteria, but also to quantify them and look at community structure. QPCR was able to detect bacteria presence in 34 percent, 31.6 percent, and 0 percent for V.vulnificus, V.parahaemolyticus. thermolabile hemolysin (tlh) and thermostable direct hemolysin (tdh) genes, respectively. Statistical analysis of the QPCR results found that there was no significant difference between the length of fish, location of catch or species of fish in relation to the abundance of bacteria. T-RFLP was able to detect the presence of bacteria in approximately 70 percent of the samples surveyed. Bands produced from T-RFLP were able to be grouped into five different ranges. The most frequently occurring band fell in the range of 213-219 base pairs, and the most common number of bands per sample was 1 band. This study found that both QPCR and T-RFLP were better assays than conventional microbial methods for detecting the presence of V. vulnificus and V. parahaemolyticus on catfish fins. QPCR proved to be the most rapid detection method. Based on this study, it was determined that these Vibrio spp. bacteria have some type of relationship with A. felis and B. marinus. This information may be useful to the medical community for determining when there is a greater risk of infection via catfish puncture wounds.

Thesis (doctoral)--Universiteit van Amsterdam, 1922. / Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 95-114).

Thesis (M.Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 95-114). Also available in print.

No description available.

Vibrio vulnificus is a human pathogen commonly found in coastal and estuarine waters in temperate and subtropical regions across the world. The ecology of V. vulnificus has been studied in these regions primarily using cultured-based methods for enumeration of V. vulnificus from the environment. Optimal temperature and salinity ranges have been established, but relationships with other environmental parameters have not been studied as extensively. The primary objective of this study was to better understand the ecology of V. vulnificus and how environmental parameters found in south Texas bays and estuaries regulate its distribution. A recently developed molecular biological technique for the direct enumeration of V. vulnificus from estuarine water column samples was used to test three hypotheses: 1) V. vulnificus makes up a greater percentage of the total bacterial population in the water column under low oxygen conditions; 2) Powderhorn Lake serves as a pointsource for V. vulnificus in Matagorda Bay; 3) Higher V. vulnificus concentrations are found in the water column when oyster reefs are present. These hypotheses were formed to improve predictive models, identify potential hot-spots for V. vulnificus in the water column, and to better inform stakeholders as to when and where risk of infection might be greatest. Dissolved oxygen was rarely low enough in the environment to stress aerobic bacteria in the water column, so the first hypothesis could not be appropriately tested. Neither higher concentrations nor detection frequencies of V. vulnificus were found in Powderhorn Lake compared to the rest of the bay, so Powderhorn Lake was not identified as a point-source for V. vulnificus. Higher concentrations and detection frequencies of V. vulnificus were not found at sites with oyster beds, so oyster beds cannot be used as indicators of higher concentrations of V. vulnificus in the water column. Interestingly, patchiness of V. vulnificus was observed temporally and spatially throughout the sampling region of Matagorda Bay, on a scale that has not been frequently examined. Variation occurred between samples in close proximity to one another, as well as between sampling dates. This distribution exhibited a small scale patchiness not frequently reported in past studies.

Graduation date: 1972

Thesis (Ph. D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1998? / Includes bibliographical references (leaves 135-166).

Frankfurt (Main), Univ.,Diss., 2003. / Erscheinungsjahr an der Haupttitelstelle: 2002. Computerdatei im Fernzugriff.