Chlamydia trachomatis is the most common bacterial agent of sexually transmitted infections worldwide and a common co-infection in AIDS patients. Chlamydial genital tract infections are often asymptomatic; therefore many infections go untreated and result in complications like chronic inflammation, ectopic pregnancy, and pelvic inflammatory disease. Chlamydia share a unique developmental cycle and under stress, can enter a state known as persistence, in which the bacteria are noninfectious but still viable. Removal of the stressor allows the chlamydiae to re-enter and complete the developmental cycle. Exposure to low-dose quinolones can cause the chlamydiae to enter persistence and halt the developmental cycle. Notably, 1 in 20 people living with HIV/AIDS also suffers from chlamydial infections. Since the anti-HIV drug Elvitegravir (EVG) is a quinolone derivative, we hypothesized that EVG exposure would inhibit chlamydial development. To ascertain whether EVG affects chlamydial development, HeLa cells were infected with C. trachomatis or C. muridarum and then either mock treated or treated with EVG. The percent infectivity and production of infectious progeny were determined by immunofluorescence assay and chlamydial titer assay, respectively. Transmission electron microscopy (TEM) was used to examine chlamydial morphology and determine whether EVG caused Chlamydia to become persistent. Though percent infectivity and chlamydial morphology were similar between treated and untreated Chlamydia-infected cells, the production of infectious progeny was significantly decreased in EVG-exposed Chlamydia-infected cells. These data indicate that EVG is not a persistence-inducer, but does inhibit chlamydial development in vitro. In other studies, we tested chlamydial polymorphic membrane protein (PMP) expression in chlamydia/HSV co-infected cells by immunofluorescence staining. Since penicillin-induced persistence decreases the expression of some chlamydial PMPs, we hypothesized that expression of PMP-A and PMP-B would be decreased by HSV-induced persistence. The results indicated that there was no significant difference in expression of PMP-A or PMP-B in co-infected versus C. trachomatis singly-infected cells. These data suggest that PMP expression is not a good indicator of chlamydial persistence when induced by HSV.

Streptococcus and Staphylococcus were collected from patients hospitalized at the Oregon Burn Center, Emanuel Hospital, Portland, Oregon, between October 27, 1980 and January 1, 1981. Forty-five isolates of Staphylococcus and twenty-one isolates of Streptococcus, Lancefield Group D, were included in the investigation. The objectives of the investigation were: (i) to identify to the species level all isolates, (ii) to determine their susceptibility to antimicrobial agents, (iii) to test the organisms. over time for increasing resistance to silver, (iv) to determine, if present, a bacterium harbored within the burn.unit (nosocomial bacterium), and (v) to determine any recognizable pattern of successive bacterial colonization which occurred in hospitalized patients.

Ready-to-eat vegetable salads containing lettuce as a main ingredient have become popular food items in recent years. Microorganisms associated with these products determine their shelf-life, sensory appeal and safety. This thesis investigates the bacterial ecology of lettuce, aspects of their pre-harvest contamination with microorganisms, and the presence of antimicrobial constituents in such produce. Commercial pesticides (insecticides, herbicides, fungicides), used during lettuce cultivation were examined as potential sources of microbial contaminants. None of the pesticide concentrates contained viable microorganisms. After reconstitution in water, two of the pesticides supported growth of inoculated species of Pseudomonas, Salmonella and Escherichia coli. Pesticides reconstituted in agricultural waters (bore, dam and river) supported the growth of microorganisms (e.g. Pseudomonas, Acinetobacter, Aeromonas spp. and coliforms) naturally present in these waters. Unless properly managed, pesticide application could contribute microbial contaminants to vegetable produce, thereby affecting their quality. Bacterial species associated with retail samples of lettuce were examined by plate culture on Tryptone Soy Agar and PCR-DGGE analysis. Macerates and rinses of lettuce sub-samples with and without addition of Tween 80 were examined to maximize bacterial recoveries. Predominant bacteria isolated by agar culture included species of Pseudomonas, Agrobacterium, Curtobacterium and Burkholderia, at populations of 103-106 cfu/g. PCR-DGGE was unable to recover the same incidence of species as agar culture and failed to detect bacteria in many samples. In some samples, PCR-DGGE detected species of Bacillus, Pseudomonas, Serratia and Acinetobacter, not found by culture. Failure of the PCR-DGGE analyses was attributed to interference by plant chloroplast DNA. Preparative agarose gel electrophoresis of lettuce macerates was necessary to remove chloroplast DNA before application of PCR-DGGE analysis. Thirty percent of lettuce samples contained Acinetobacter species at 101-104 cfu/g when examined after culture on minimal salts agar or enrichment in Baumann enrichment medium. Other Acinetobacter media failed to give reliable isolation of these species from lettuce and salad vegetables. Lettuce could be an environmental source of Acinetobacter nosocomial infections. Juices, solvent extracts and supercritical fluid carbon dioxide extracts of lettuce and capsicum samples did not exhibit antimicrobial action against a range of food spoilage and pathogenic bacteria.

The contamination of fresh water by phosphates in poultry litter results in substantial eutrophication of fresh water causing fish kills and other types of environmental damage. The poultry indus try in Kentucky is expanding rapidly. The number of broilers is increasing as more poultry farms are established in the state producing waste that needs disposal. Investigations were made to study the possibility of using microorganisms normally found in poultry litter to sequester phosphate, thereby delaying phosphate runoff after litter is applied to croplands. Little is known, however, about the microflora of poultry litter. Terminal restriction fragment length polymorphism of 16S rDNA from bacteria was used to investigate the bacterial diversity of poultry litter. Poultry litter was collected from a local producer. DNA was isolated using commercial kits and amplified using the polymerase chain reaction with primers specific for bacterial 16S rDNA. The amplified fragments were digested using HhaI restriction endonuclease and the DNA fragment lengths were determined. To determine the sensitivity of this method, known quantities of Escherichia coli cells were spiked into litter prior to DNA extraction. Successful amplification of the bacterial rDNA was highly variable but could be improved by passing the purified DNA through two purification columns in lieu of only one column. The detection threshold for E. coli was 10 cells, however, the results also varied widely. Bacteria capable of hyper-accumulating intracellular phosphate were isolated from poultry litter as possible tools for phosphate remediation in poultry litter. Five strains of phosphate accumulating bacteria were successfully isolated from poultry litter. Poultry litter was suspended in sterile nanopure water and 100μl was plated on BHI plates containing an addtional 750mM K2HPO4. Isolated colonies were screened for intracellular metachromatic granules using the Nile blue stain, a presumptive test for polyphosphate. Positive colonies were cultured in BHI and BHI with supplementation of K2HPO4 and free intracellular phosphate concentrations were determined in cell extracts. Total phosphates were measured in cell extracts subjected to hydrolysis by addition of 12N HCl and heating at 100°C for 60 min. Polyphosphate was determined by subtraction of free phosphates from total phosphates. Results showed five isolates of gram-positive bacteria were obtained from poultry litter. All isolates were cocci arranged in chains or clusters and were catalase positive. All isolates showed considerable levels of intracellular phosphate accumulation, which were comparable to Microlunatus phosphovorus, a bacterium known to hyper-accumulate phosphate. Biolo g analysis indicated four of the five strains isolated were Staphylococcus sp. and one strain was unidentified.

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 160-171). Also available via World Wide Web.

No description available.

The requirement of marine bacteria for seawater in the medium for growth has been observed to reflect their need for the inorganic ions in seawater for their growth and metabolism. Of these inorganic ions, the marine bacteria so far examined in contrast to most terrestrial bacterial species have been found to possess a specific requirement for Na+ for growth. The Na+ requirement for growth has been found to reflect a requirement for the transport of nutrients in marine bacterial cells. This and other information regarding the characteristics of marine bacteria have come from the studies of only a few representatives of a very small fraction of the bacterial population in the sea, and one may well ask how far these observations made with a few species are true for marine bacteria as a group of organisms? In this thesis observations made on non-luminous marine bacteria have been extended to include some representative luminous marine bacteria. In the course of these studies some similarities and differences in the nutrition and metabolism of the two groups of organisms have been noted.

No description available.

Ready-to-eat vegetable salads containing lettuce as a main ingredient have become popular food items in recent years. Microorganisms associated with these products determine their shelf-life, sensory appeal and safety. This thesis investigates the bacterial ecology of lettuce, aspects of their pre-harvest contamination with microorganisms, and the presence of antimicrobial constituents in such produce. Commercial pesticides (insecticides, herbicides, fungicides), used during lettuce cultivation were examined as potential sources of microbial contaminants. None of the pesticide concentrates contained viable microorganisms. After reconstitution in water, two of the pesticides supported growth of inoculated species of Pseudomonas, Salmonella and Escherichia coli. Pesticides reconstituted in agricultural waters (bore, dam and river) supported the growth of microorganisms (e.g. Pseudomonas, Acinetobacter, Aeromonas spp. and coliforms) naturally present in these waters. Unless properly managed, pesticide application could contribute microbial contaminants to vegetable produce, thereby affecting their quality. Bacterial species associated with retail samples of lettuce were examined by plate culture on Tryptone Soy Agar and PCR-DGGE analysis. Macerates and rinses of lettuce sub-samples with and without addition of Tween 80 were examined to maximize bacterial recoveries. Predominant bacteria isolated by agar culture included species of Pseudomonas, Agrobacterium, Curtobacterium and Burkholderia, at populations of 103-106 cfu/g. PCR-DGGE was unable to recover the same incidence of species as agar culture and failed to detect bacteria in many samples. In some samples, PCR-DGGE detected species of Bacillus, Pseudomonas, Serratia and Acinetobacter, not found by culture. Failure of the PCR-DGGE analyses was attributed to interference by plant chloroplast DNA. Preparative agarose gel electrophoresis of lettuce macerates was necessary to remove chloroplast DNA before application of PCR-DGGE analysis. Thirty percent of lettuce samples contained Acinetobacter species at 101-104 cfu/g when examined after culture on minimal salts agar or enrichment in Baumann enrichment medium. Other Acinetobacter media failed to give reliable isolation of these species from lettuce and salad vegetables. Lettuce could be an environmental source of Acinetobacter nosocomial infections. Juices, solvent extracts and supercritical fluid carbon dioxide extracts of lettuce and capsicum samples did not exhibit antimicrobial action against a range of food spoilage and pathogenic bacteria.

Three leaves of errata inserted before title page. / Bibliography: leaves 150-181. / xi, 181 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Determines whether growing cells of F. nucleatum ATCC 25586 could actually utilise peptides to provide the energy-yielding amino acid residues. Overall shows the important role of aminopeptidase in the nutrition and survival of F. nucleatum. / Thesis (Ph.D.)--University of Adelaide, Dept. of Dentistry, 1998