In response to sulphur dioxide emission reductions in North America and Europe, there has been a recent shift in research focus towards understanding ecosystem recovery. Evidence for reversibility in the effects of acidification on lake ecosystems within North America has been, for the most part, constrained to a single locality (Sudbury, Ontario). Lakes in a fume-kill area near Wawa, Ontario, present a new and rare opportunity for studying potentially rapid chemical and biological recovery patterns from extreme acidification. Several lakes acidified (pH ~3) during a period of local iron sintering from 1939 to 1998, and although minimal historical data are available, striking biological recovery has recently been observed. This study used paleolimnological techniques to track diatom (class Bacillariophyceae) responses to historical water quality changes in five fume-kill lakes near Wawa. Prior to the onset of iron sintering, the sediment-recorded diatom assemblages were dominated by species that are typically found in circumneutral or slightly alkaline lakes. Following the known occurrence of lake acidification, there was a striking shift in the sediment record towards dominance by acid- and metal-tolerant species. Water quality of the fume-kill lakes has since improved (i.e. pH has increased from ~3 to ~7 and metal concentrations have decreased). In four of the five lake cores, this was reflected by a decrease in the relative abundance of acid-tolerant species. Surprisingly, diatom communities were not progressing towards pre-disturbance species assemblages. Factors impeding the return of native species might include metal enrichment in surface sediment and potentially altered lake thermal regimes. Documenting and understanding recovery trajectories is necessary to help lake managers evaluate policy decisions regarding the efficacy of emission reduction programs and mitigation measures. This thesis provides evidence from one location in addition to Sudbury that the ecological effects of severe lake acidification can be reversed if SO2 emissions are sufficiently reduced. It also further demonstrates the complexity of recovery patterns in acidified and metal-contaminated lakes. / Thesis (Master, Biology) -- Queen's University, 2009-04-26 18:38:20.58

A rapid detection method combining immunomagnetic separation (IMS), PCR and slot blot detection was developed for the detection of Salmonella and Listeria monocytogenes in milk. Bacteria were first isolated and concentrated from phosphate-buffered saline (PBS) or milk by IMS. After extraction from diluted bacteria culture with the extraction buffer, bacterial DNA was subjected to PCR. Slot blot assay was optimized and used to measure PCR products. The lowest level of detection by this method was 40 cfu/ml in PBS or milk for both pathogens. The whole detection procedure could be completed within 7 h. Moreover, this detection method is simple and easy to handle for a large number of samples. Using multiplex PCR (amplification of two different bacterial DNA in the same PCR tube) and slot blot, simultaneous detection of both bacteria was also assessed. The detection sensitivities of 103 cfu/ml for both bacteria were the same as when PCR and slot blot were used for each bacterium separately. The combination of IMS, PCR and slot blot seems to give a highly sensitive and time-efficient procedure, which could be used for routine detection of Salmonella and L. monocytogenes in milk.

In this study, pollen contamination (measured by the number of seeds pollinated by pollen not belonging to any of the clones on the seed orchard) is compared between open pollination and isolated pollination environments in a Scots pine (Pinus sylvestris) seed orchard called Västerhus, located outside Önsköldsvik. In this seed orchard a tent experiment is taking place. Skogforsk has built six large tents covering 12-14 trees with each tent. Fertilization patterns were compared between one tree in a tent with a supplementation of pollen from five clones not represented in the tent and another tree of the same clone subject to open pollination outside the tents. By using DNA markers the paternity was determined for 48 seeds from each tree. The results show a big difference in pollen contamination between the two trees. The tree inside the tent showed a contamination rate of 0% and the tree from the open pollination had a contamination rate of 20,5%. No difference was found in the numbers of different fathers although the selfing rate of 4,26% was higher in the tent than the selfing rate of 2,56% observed in the open pollination environment. These results match the results of other studies done on the same orchard pretty well and therefore tent isolation with a supplementary pollination can be a good way to reduce unwanted pollen contamination.

In this study, pollen contamination (measured by the number of seeds pollinated by pollen not belonging to any of the clones on the seed orchard) is compared between open pollination and isolated pollination environments in a Scots pine (Pinus sylvestris) seed orchard called Västerhus, located outside Önsköldsvik. In this seed orchard a tent experiment is taking place. Skogforsk has built six large tents covering 12-14 trees with each tent. Fertilization patterns were compared between one tree in a tent with a supplementation of pollen from five clones not represented in the tent and another tree of the same clone subject to open pollination outside the tents. By using DNA markers the paternity was determined for 48 seeds from each tree. The results show a big difference in pollen contamination between the two trees. The tree inside the tent showed a contamination rate of 0% and the tree from the open pollination had a contamination rate of 20,5%. No difference was found in the numbers of different fathers although the selfing rate of 4,26% was higher in the tent than the selfing rate of 2,56% observed in the open pollination environment. These results match the results of other studies done on the same orchard pretty well and therefore tent isolation with a supplementary pollination can be a good way to reduce unwanted pollen contamination.

The incidences of diarrhoeal episodes in infants and children have mostly been associated with the consumption of contaminated weaning foods. This is especially true in developing countries where factors such as the lack of sanitation systems and electricity have been found to contribute to an increase in the incidence of microbiologically contaminated weaning foods. The process of fermentation has been found to reduce the amount of microbiological contamination in such foods as a result of the production of antimicrobial compounds such as organic acids, peroxides, carbon dioxide and bacteriocins. In this study, microbiological surveys were conducted on sorghum powder samples and their corresponding fermented and cooked fermented porridge samples collected from an informal settlement of the Gauteng Province of South Africa. The process of fermentation was found to result in significant decreases (P>0.05) in Gram-negative counts and spore counts, while aerobic plate counts decreased slightly. Lactic acid bacteria counts, however, increased significantly (P>0.05). The cooking process was found to result in further significant decreases (P>0.05) in all counts. Sorghum powder samples and fermented porridge samples were found to be contaminated with potential foodborne pathogens, including Bacillus cereus, Clostridium perfringens and Escherichia coli, however, none of the pathogens tested for were detected in any of the cooked fermented porridge samples. SDS-PAGE and phenotypic analysis of 180 lactic acid bacteria isolated from sorghum powder samples and their corresponding fermented and cooked fermented porridge samples showed that a majority of the isolates were lactobacilli and leuconostocs, however, some isolates were identified as pediococci and lactococci. These results demonstrated the heterogeneity of the lactic acid bacteria isolates that were associated with fermentation processes in this study. Of the lactic acid bacteria identified, Lactobacillus plantarum and Leuconostoc mesenteroides strains were found to have the highest distribution frequencies, being distributed in 87% and 73% of the households, respectively. Analysis of Lactobacillus plantarum (58) and Leuconostoc mesenteroides (46) strains isolated from sorghum powder samples and corresponding fermented and cooked fermented porridge samples by AFLP fingerprinting showed that they originated from a common source, which was sorghum powder. There was, however, evidence of strains that may have been introduced at household level. Antimicrobial activity of selected lactic acid bacteria was found to be mainly due to a decrease in pH in fermented and cooked fermented porridge samples. None of the lactic acid bacteria tested seemed to produce bacteriocins.

Casein – the main albumen constituent of milk. Food casein is used in the production of caseinat. Caseinats are used in the production of food concentrates, medicines, and cheese products. In addition, they may be used as casein glue. Goals of thesis. To determinate total bacterial contamination of acid casein edible, isolate and identify pathological microorganisms. 1. To determine the general bacterial contamination of edible acid casein samples. 2. To determine the influence of thermophylic bacteria on the general bacterial contamination. 3. To determine the general bacterial contamination of repeatedly researched edible acid casein samples and the presumable quantity of coliformic germs. 4. To define and identify the patological microorganisms out of edible acid casein samples. 5. To determine the chemical composition of edible acid casein samples. Results. Micro flora of crude milk constitutes certain part of micro flora, found in powdered milk. However, the increased level of general contamination and coliform germs shows the signs of secondary contamination. The enlarged bacteriological contamination, which exceeded the preset limit of 3.0x104 CFU/g, was identified in 3 per cent of analyzed acid casein edible samples. This was caused by impurity of crude milk. During the acid casein edible casein production process, the temperature of pasteurization was reached twice and in addition to that, comparatively low pH was maintained. These conditions are not hospitable for... [to full text]

Natural attenuation of trichloroethene (TCE) and technetium (99Tc) was studied for five consecutive seasons (from January 2002 to January 2003) in Little Bayou Creek. The stream receives ground water discharge from an aquifer contaminated by past waste disposal activities at the Paducah Gaseous Diffusion Plant (PGDP), a uranium enrichment facility near Paducah, Kentucky. Results from stream gaging, contaminant monitoring, tracer tests (with bromide, nitrate, rhodamine WT and propane) and simulation modeling indicate the TCE is naturally attenuated by volatilization and dilution, with volatilization rates related to the ambient temperature and surface discharge rate. The only apparent mechanism of 99Tc attenuation is dilution. Travel times of non-gaseous tracers were found to be similar and have highest values in October and lowest in June. It was also estimated from modeling that the transport of the solutes in the stream was mostly one-dimensional with insignificant secondary storage.

We hypothesized that temporal features of EEG are altered in sleep apnea subjects comparedto normal subjects. The initial aim was to develop a measure to discriminate sleep stages innormals. The longer-term goal was to apply these methods to identify differences in EEGactivity in sleep apnea subjects from normals. We analyzed the C3A2 EEG and anelectrooculogram (EOG) recorded from 9 normal adults awake and in rapid eye movement(REM) and non-REM sleep. The EEG signals were filtered to remove EOG contamination. Twomeasures of the irregularity of EEG signals, Sample Entropy (SpEn) and Tsallis Entropy, wereevaluated for their ability to discriminate sleep stages. SpEn changes with sleep state, beinglargest in Wake. Stage 3/4 had the smallest SpEn (0.57??0.11) normalized to Wake values,followed by Stage 2 (0.72??0.09), REM (0.75??0.1) and Stage 1 (0.89??0.05). This pattern wasconsistent in all the polysomnogram records analyzed. Similar pattern was observed in leadO1A2 as well. We conclude that SpEn may be useful as part of a montage for assessing sleepstate. We analyzed data from sleep apnea subjects having obstructive and central apnea eventsand have made some preliminary observations; the SpEn values were more similar across sleepstages and also high correlation with oxygen saturation was observed.

Several powdered food products were screened using repetitive element palindrome PCR (rep-PCR) for the presence of enterotoxin producing species of Bacillus. Samples from these products were screened by being placed into a tryptone-peptoneglucose-yeast enrichment medium (TPGY), heat-treated, and shake-incubated. DNA was extracted using a modification of established protocol, leading to the development of an optimized method for each food system. Purified DNA was amplified through rep-PCR using extragenic sequence-targeting primers and optimized for each food product. Amplified PCR products were analyzed electrophoretically and viewed using an ultraviolet photodocumentation system. Bacillus cereus positive control DNA fingerprints were compared to banding patterns from enriched food samples, revealing the presence of the typical diagnostic 1,230 bp band in non-fat dry milk (NFDM). Restriction Fragment Length Polymorphism (RFLP) with Alu I restriction enzyme was performed on the 1230 bp diagnostic band from NFDM and displayed a profile consistent with Bacillus cereus positive control. RPLA (Reverse Passive Latex Agglutination) and BDE ELISA (Bacillus Diarrhoeal Enterotoxin Enzyme Linked Immunosorbent Assay - Tecra Diagnostics) confirmed the presence of HBL and NHE enterotoxin production in NFDM, Coffee creamer, infant milk formula, and two lecithin samples. / Department of Biology

The risk of waterborne infections acquired from the consumption of contaminated water is related to changes in source water fecal contamination, which is often influenced by land-use and hydro-meteorological conditions in the surrounding watershed. The impact of land-use composition on surface water contamination was explored in order to determine the risk of surface water contamination associated with land-use change. Highest contamination was observed in watersheds characterized by more than 12.5% agricultural and more than 1.6% urban land (mean fecal coliform (FC) concentration of these 5 sites = 135 CFU 100ml-1 while the British Columbia (BC) raw water quality guideline = 100 CFU 100ml-1). Contamination increased exponentially, and violated BC raw water quality guidelines with greater frequency, in relation to greater agricultural land in the upstream watershed. Additional factors, such as sewage treatment plants, low dilution in smaller streams, and higher temperatures were also associated with greater contamination. These results indicate the high level of risk posed by agricultural and urban development and the need for source water protection. Fecal contamination levels in source water are also influenced by rainfall and snowmelt-induced surface runoff that transport diffuse fecal contaminants into surface water. Seasonal levels of fecal contamination in surface water was related to the watershed hydro-climatic regime for around half of the watersheds examined. Watersheds with snowmelt-dominant (SD) runoff regimes showed stronger evidence of hydro-meteorological variability driving seasonal contamination levels than those with rainfall and snowmelt-influenced (RSI) and rainfall-dominant (RD) runoff regimes, and thus are more prone to experiencing changes to seasonal variability resulting from climate change. Projected increases in mean annual temperatures of between 1.70C and 4.00C towards the end of the 21st century will alter existing runoff regimes within watersheds. For SD watersheds that remain below freezing and continue to accumulate snowpack during the cold season, transport of fecal contamination will likely occur earlier in the year with greater intensity. Fecal coliform transport in summer is likely to decrease, especially in SD watersheds in which fecal contamination is driven by summer rainfall events. Snowmelt-dominant watersheds transitioning toward a RD runoff regime will experience less contamination during spring but increased contamination during late fall and winter. The extent to which these changes in runoff regime will influence surface water fecal contamination will vary among watersheds. Further investigation is required to identify factors that enhance or mitigate the association of surface water fecal contamination with rainfall and snowmelt-induced runoff in order to identify specific site vulnerability to changing seasonal contamination levels. Total precipitation within BC is projected to increase by 20-30% towards the end of the 21st century. The association of annual FC variability with snowmelt and rainfall variability was examined in order to assess the capacity of such increases to raise the level of surface water fecal contamination. Greater total annual and seasonal rainfall and/or river discharge increased surface water fecal contamination for 58% (11/19) of the sites examined. Hydro-meteorological variability influenced FC concentration during winter, the season of greatest precipitation, and spring, the season of greatest snowmelt, but not during summer or fall. Reduced contamination levels during the El Niño event in 2002/03 were associated with a mean reduction in river discharge during spring and summer. These associations suggest that the risk of increased surface water fecal contamination in response to higher precipitation is likely to be greatest in winter for RD watersheds and spring for SD watersheds, although the magnitude of impact will vary among sites. Climate change and land-use activities within watersheds have the capacity to alter the timing and amount of surface water fecal contamination. These factors are likely to act synergistically by increasing the presence and transport of fecal contaminants within watersheds. Such relationships should be carefully considered to aid the assessment and mitigation of the risk of source water contamination associated with land-use and climate change. / Graduate