I investigated whether Neogobius melanostomus, an invader of biodiversity “hot-spots” in Ontario facilitates or inhibits unionid mussel recruitment by serving as a host or as a sink for their parasitic larvae (glochidia). Infestation and metamorphosis rates of four mussel Species at Risk (Epioblasma torulosa rangiana, Epioblasma triquetra, Lampsilis fasciola, and Villosa iris) and one common species (Actinonaias ligamentina) on N. melanostomus were compared to rates on known hosts in the laboratory. All species successfully infested N. melanostomus, but only E. triquetra, V. iris, and A. ligamentina successfully metamorphosed, albeit at low rates. Neogobius melanostomus collected from areas of unionid occurrence in the Grand and Sydenham rivers exhibited body burdens of 39.4% and 5.1%, respectively. Analyses indicate that N. melanostomus serves more as a sink for glochidia than as a host for unionids, thereby limiting recruitment, which is a novel way by which N. melanostomus is affecting native mussel species.

This thesis concerns the investigation of the neuroprotective effects of the peptides relaxin-2 and relaxin-3. Previous studies have shown that intracerebral relaxin-2 reduces brain lesion size in an in vivo model of stroke, thereby providing evidence of a neuroprotective action of relaxin-2. This thesis set out to extend this work to determine whether or not relaxin-2 and relaxin-3 protected neural tissues from stroke in vivo and to determine the mechanisms by which relaxin-2 and relaxin-3 may protect astrocytes from injury by affecting migration, resistance to hypoxia and prevention of apoptosis. The first set of experiments show that relaxin-2 and relaxin-3 pre- and post-treatments following stroke induction protect neural tissues from cerebral damage in vivo. The next experiments show that relaxin-2 and relaxin-3 increase astrocyte migration in vitro through nitric oxide, phosphoinositide 3-kinase and matrix metalloproteinase-mediated pathways. A third set of experiments show that relaxin-2 and relaxin-3 treated astrocytes exhibited a higher viability compared to untreated astrocytes when exposed to oxygen glucose deprivation for 24 hours. Astrocytes that were cultured with relaxin-2 or relaxin-3 also showed a lower production of reactive oxygen species compared to astrocytes that were exposed to oxygen glucose deprivation alone. Finally, relaxin-2 and relaxin-3 protected astrocytes from 24-hour apoptosis injury that was induced by tumor necrosis factor alpha and hydrogen peroxide. Taken together these experiments provide evidence that relaxin-2 and relaxin-3 peptides protect neural tissues from the deleterious effects of cerebral ischemia in vivo and help elucidate some of the cellular mechanisms by which relaxin peptides might protect the brain. Furthermore, these data show that relaxin-2 and relaxin-3 act directly on astrocytes, the most numerous cell type in the brain, to increase astrocyte migration and to protect these cells from some of the deleterious effects of stroke, namely hypoxia and apoptosis.

This thesis investigates species diversity and patterns of molecular evolution in Arachnida through DNA barcoding. The first chapter assesses mite species richness through comprehensive sampling at a subarctic location in Canada. Barcode analysis of 6279 specimens revealed nearly 900 presumptive species with high rates of turnover between major habitat types, demonstrating the utility of DNA barcoding for biodiversity surveys of understudied taxa. The second chapter explores nucleotide composition, indel occurrence, and rates of amino acid evolution in Arachnida. The results suggest a significant shift in nucleotide composition in the arachnid subclasses of Pulmonata (GC = 37.0%) and Apulmonata (GC = 34.2%). Indels were detected in five apulmonate orders, with deletions being much more common than insertions. Finally, rates of amino acid evolution were detected among the orders, and were negatively correlated with generation length, suggesting that generation time is a significant contributor to variation in molecular rates of evolution in arachnids.

Darbo tikslas – ištirti bičių kolonijų produkcines ir reprodukcines savybes, laikant įvairaus dydţio aviliuose. Siekiant šio tikslo bus iškelti sekantys uţdaviniai: 1. Įtakoti bičių kolonijų pavasarinio apsiskraidymo laiką; 2. Įvertinti bičių svorį po pavasarinio apsiskraidymo; 3. Nustatyti avilio tipo įtaką bičių šeimų ţiemojimui bei jų fiziologinei būklei; 4. Nustatyti traninių perų pasirodymo laiką bičių kolonijoje; 5. Nustatyti Varroa destructor erkių įtaką tranų lervučių masei; 6. Nustatyti avilio talpumo įtaką motinių lopšelių skaičiui bei bičių produkcijai. Buvo stebimas bičių kolonijų pavasarinis apsiskraidymas, sveriamos bitės po pavasarinio apsiskraidymo, stebimas aptūptų bitėmis korių skaičius 2010–2011 metais. Apţiūrimi pirmieji traniniai perai bičių kolonijoje, sveriant tranų lervas nustatinėjama erkių Varroa destructor įtaka jų masei, įvertinama bičių kolonijų fiziologinė būklė. Taip pat registruojami motininiai lopšeliai bičių šeimose ir medaus kopimo metu atliekama išsukto medaus apskaita. Bičių apsiskraidymas vyko dviem etapais, pirmą kartą apsiskraidė 4 bičių šeimos, o antra likusios 12 šeimų. Ištyrus bičių svorį po pavasarinio apsiskraidymo paaiškėjo, kad iš 60 % tirtų bičių svoris yra 0,11 g, o likusių bičių svoris maţesnis. Nustatant avilio įtaką bičių šeimų ţiemojimui 2010–2011 metais, buvo nustatyta, kad 27 korių aviliuose bičių šeimos yra stipriausios. Apţiūrint bičių kolonijas, iš 16 bičių šeimų, 4 šeimos buvo su pirmaisiais traniniais perais... [toliau žr. visą tekstą] / The aim – to investigate bee colony productive and reproductive characteristics. To achieve this objective will be to raise the following goals: 1. Influence first fly colonies in spring time; 2. To evaluate the weight of the bees in the spring after first fly; 3. Identify type of impact on the hive of bees and their families in winter physiological condition; 4. Set the time of the appearance of peers traninių bee colony; 5. Determine the impact of Varroa destructor mites in drone larvae masses; 6. Set the capacity of the hive mother influence the number of nursery and bee products. Colonies were observed in spring first flight, weighed after spring first flight bees, bees, combs sits observed number 2010–2011 years. Also examined the first drones peers bee colony, weighing the drone larvae of identical mite Varroa destructor influence their weight, assess the physiological state of bee colonies. The nursery also recorded maternal families of honey bees climbing in done unfolded honey accounting. First flight bees gone through two phases, the first flight four colonies, and the second the remaining 12 families. Examination of the weight of the bee first fly spring showed that 60% of tested bees weighing 0.1138 g and the weight of the remaining bees. In determining the impact of the hive bee families influence winter 2010–2011, has been found that 27 hives of bees honeycomb is the strongest of the family. Survey of bee colonies in 16 hives, four families were the first drone... [to full text]

Rhinoceroses are arguably the most endangered of all large mammal taxa. In order for ongoing conservation of this species to be successful, it is crucial to accurately characterize the remaining genetic diversity for all rhinoceros species. To do this, I optimized a standard suite of 24 taxon-specific rhinoceros microsatellite loci. These loci have the power to provide the most comprehensive estimate of comparative microsatellite genetic diversity within and among the four extant African and Asian rhinoceros genera. These loci were further used to evaluate the comparative influences of rhinoceros species versus microsatellite taxonomic origin as predictors of rhino microsatellite diversity, and finally to examine the evolutionary relationships between extant rhino taxa. The African black michaeli rhino subspecies had the highest level of microsatellite genetic variability of all available rhinos, while southern white and Indian rhinos were the least variable rhinos. These findings also suggested that species and taxonomic origin of microsatellite loci were both significant predictors of microsatellite heterozygosity in rhinoceroses. A weak association between the Sumatran and black rhinos was found with a DLR neighbour-joining tree. The standard loci were able to assign unique genotypes to all available rhinos as well as differentiate between all rhino species by correctly assigning individual rhinos back to their respective populations. / Thesis (Master, Biology) -- Queen's University, 2008-07-02 23:01:32.553

Previous investigations have demonstrated that reactive oxygen species such as hydrogen peroxide (H2O2) have the ability to alter electrophysiological and mechanical properties of rat ventricular cardiac myocytes. However, despite the breadth of the literature, there is little definitive consensus on the cellular mechanisms. The purpose of this study, therefore, was to study the cellular mechanism of action of H2O2 and test whether H2O2-mediated affects were partially a result of reverse-mode Na+/Ca2+ exchanger (NCX) activity. Unloaded cell shortening, intracellular Ca2+ transients, caffeine-induced Ca2+ transients, L-type Ca2+ channel recordings, and action potential waveforms were recorded in the presence of combinations of different compounds including Cd2+, H2O2, and KB-R7943. H2O2 was found to cause significant positive inotropy by an increase in contractility of 80 ± 20 % (n=6) and an increased amplitude of Ca2+ transients by 24 ± 14 % (n=8), relative to pre-treatment values. Interestingly, H2O2 caused an increase in contractility even in the presence of Cd2+ block from 4 ± 1 % (n=9) to 15 ± 3 % (n=5) of resting cell length. Using caffeine pulse experiments to induce unloading of the sarcoplasmic reticulum (SR), we found that 100µM H2O2 did not significantly alter SR Ca2+ load. Under control conditions, H2O2 significantly increased L-type Ca2+ currents while this H2O2-induced increase was not observed in myocytes pretreated with Cd2+. Positive inotropy in the presence of H2O2 was blocked using 10µM KB-R7943, a selective reverse-mode inhibitor of the NCX. However, it was found that 10µM KB-R7943 alone altered action potential profile and suppressed normal contraction. Altogether, the major finding of this study is that H2O2 has the ability to enhance myocardial contractility, even under conditions of L-type Ca2+ channel inhibition, through a mechanism that likely involves reverse-mode of the NCX. / Thesis (Master, Physiology) -- Queen's University, 2009-03-31 14:00:34.21

Benzene is a ubiquitous environmental pollutant and a known human leukemogen. Early-life exposure to environmental carcinogens, including benzene, may lead to genomic instability in the fetus, ultimately leading to an increased risk for the development of childhood cancers including leukemia. It is possible that exposure to benzene results in DNA damage that may either be left unrepaired or be repaired erroneously causing genotoxicity. The first objective of this study was to determine if exposure of fetal hematopoietic cells to p-benzoquinone, a known toxic metabolite of benzene, increased DNA recombination in the pKZ1 model of mutagenesis. A significant increase in recombination was observed following exposure to 25 μM and 50 μM p-benzoquinone for 2, 4, 8, and 24 hours. A significant increase in recombination was also observed following exposure to 25 μM p-benzoquinone for 30 min, 45 min, and 1 hour, but not 15 min as compared to vehicle alone. Secondly, this study determined if exposure of fetal hematopoietic cells to p-benzoquinone resulted in DNA damage using γ-H2A.X as a marker for DNA double strand breaks and 8-hydroxy-2’-deoxyguanosine as a marker of oxidative DNA damage. A significant increase in γ-H2A.X foci formation was observed following exposure to 25 μM p-benzoquinone for 30 min, 45 min and one hour. Exposure of fetal hematopoietic cells to 25 μM p-benzoquinone did not significantly increase oxidative DNA damage at any of the examined time points. The third objective of this study was to determine whether or not reactive oxygen species were involved in the observed increase in DNA damage and recombination. Exposure to 25 μM p-benzoquinone for 15 min and 30 min, but not 45 min or one hour, led to an increase in reactive oxygen species production as measured by 5-(and-6)-chloromethyl-2-7-dichlorodihydrofluorescein diacetate fluorescence. Additionally, pretreatment with 400 U/mL PEG-catalase, an antioxidative enzyme, attenuated the increases in both DNA recombination and DNA double strand breaks as compared to treatment with p-benzoquinone alone. These studies indicate that p-benzoquinone is able to induce DNA damage and recombination in fetal hematopoieitic cells and that reactive oxygen species and oxidative stress may be important in the mechanism of toxicity. / Thesis (Master, Pharmacology & Toxicology) -- Queen's University, 2010-07-23 15:44:05.381

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