Biology / Biologie

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Conservation des amphibiens : de la theorie à l'action
(Acfas-Sudbury, 2006) Lesbarrères, David
Effets des facteurs environnementaux du drainage minier acide sur les membranes d'Acidithiobacillus ferrooxidans
(Acfas-Sudbury, 2007) Mykytczuk, Nadia; Leduc, Leo; Trevors, Jack T; Ferroni, Garry D
The role of water clarity in structuring niche dimensions and overlap between smallmouth bass and walleye
(Laurentian University of Sudbury, 2013-07-30) Stasko, Ashley D.
Smallmouth bass (Micropterus dolomieu) have experienced substantial range expansions in northern Ontario over the past century, with adverse consequences for native salmonid predators. It is unclear how climate-induced water clarity shifts will affect interactions between native dark-adapted walleye (Sander virteus) and invading smallmouth bass in northern Ontario. This study used stable isotopes of nitrogen (15N/14N) and carbon (13C/12C) in fish muscle tissue to investigate how resource partitioning between walleye and smallmouth bass is related to water clarity in 34 small (100-200 ha) Boreal Shield lakes (ranging from 1 to 8.5 m Secchi depth, and from 3.2 to 13.1 mg/L DOC). Quantitative metrics of trophic niche dimensions (based on the size, position, and dispersion of multivariate ellipses drawn around sampled individuals in δ15N vs. δ13C biplot space) were calculated for each individual population and used to determine trophic interactions and niche overlap between sympatric walleye and smallmouth bass. Linear and multiple regressions were then used to explore potential relationships between trophic interactions and water clarity. Available habitat and fish assemblage data was also explored for potential influences on isotopic niche dimensions and trophic interactions of walleye and smallmouth bass. Total occupied niche space decreased significantly with increasing water clarity for smallmouth bass as populations occupied a narrower range of trophic levels and made greater use of pelagic resources. In contrast, walleye trophic niche dimensions did not respond significantly to water clarity. Isotopic niche overlap ranged from 0 to 65%, but no metric of trophic overlap was significantly related to water clarity. Other abiotic and biotic variables, however, did have a significant influence on the similarity between some aspects of walleye and smallmouth iv bass isotopic niche dimensions (but not interaction). Both species fed on more isotopically similar carbon sources as lakes became shallower, which may be a result of a lack of distinct littoral and limnetic habitats. Walleye and smallmouth bass niche size also became more similar with increasing DOC but this may be a result of lower prey diversity. Both species also occupied more similar average food web positions as yellow perch relative abundance increased, indicating that the exploitation of yellow perch by both species increased with perch abundance. Together with other studies that have found little evidence for an impact of smallmouth bass on walleye fitness and abundance, this research suggests that, unlike salmonid and cyprinid species, walleye may be resilient against smallmouth bass invasions regardless of water clarity conditions in oligotrophic boreal lakes.
Comparative morphogenesis of cynipid leaf galls induced by Diplolepis polita and Diplolepis nebulosa (Hymenoptera: Cynipidae) and modification by inquilines of the genus Periclistus (Hymenoptera: Cynipidae)
(Laurentian University of Sudbury, 2013-07-30) Fenwick, Brandy
Cynipid galls are atypical plant growths induced by wasps in the family Cynipidae that provide larvae with shelter and nutrition. Larvae gain control of attacked plant organs and send them on a new developmental trajectory, with three developmental phases known as initiation, growth, and maturation. Each of the approximately 1400 species of cynipid gall wasps manipulates plant tissues in a slightly different manner such that galls of each species are structurally distinct. Although the means by which cynipids initiate galls has fascinated naturalists for hundreds of years, the basic events in gall induction are still poorly understood. In an attempt to understand the galling strategies and developmental processes responsible for species-specific galls, I chose to compare the intimate details of life history strategies of two taxonomically related species attacking the same plant organs. The strategies included host specificity, phenology, and oviposition strategies, along with gall development to highlight basic events in gall biology and reveal possible stages in past speciation events. It is argued that differences in phenology and gall development played a role in driving speciation and thus, the patterns observed today are a result of extensive ecological interactions in the past that have influenced the evolution of these complex insect-plant relationships. Two species of cynipid wasps of the genus Diplolepis that occur on the wild roses of central Ontario proved to be ideal candidates for the study. One species, Diplolepis polita, induces single-chambered, prickly galls found in clusters on the adaxial surface of leaflets of Rosa acicularis whereas, the other species, D. nebulosa, induces single-chambered, smooth-surfaced galls found in clusters on the abaxial surface of the leaflets of Rosa blanda. Galls at all stages of development, from freshly oviposited eggs to maturation, were found in large numbers for both species. Leaf tissues from the bud stage to maturity of both species of rose were fixed in FAA, embedded in paraffin, sectioned and stained for histological study. Likewise, leaf tissues with freshly oviposited eggs of both species and galls from immaturity to maturity were fixed, sectioned, and stained. Comparing the several thousand slides made for the study revealed that galls of D. polita and D. nebulosa differ in their developmental events as well as the anatomy of their mature galls. Like the galls of all species of cynipids, those of D. polita and D. nebulosa are composed of distinct layers of gall cells known as nutritive, parenchymatous nutritive, sclerenchyma, cortex, and epidermis. Galls of D. polita consist of nutritive cells, parenchymatous nutritive cells, and an epidermis throughout the initiation and growth phases. Larvae remain small in relation to chamber volume until the maturation phase, when a hard layer of sclerenchyma differentiates. In contrast, galls of D. nebulosa have a delayed initiation phase, where galls remain nearly undetectable on leaflets for several weeks after oviposition before they enter the growth phase. Freshly-hatched larvae are protected by two layers of bowl-shaped patches of sclerenchyma that differentiates soon after initiation, along with nutritive cells and parenchymatous nutritive cells that surround the larval chambers, but galls of this species develop without an external layer of epidermis. Galls become spherical as they mature and a second layer of sclerenchyma differentiates within the walls of the galls, as does a layer of spongy cortex that appears between the second layer of sclerenchyma and the gall exterior. Larvae of D. nebulosa occupy nearly the entire volume of their larval chambers throughout gall development. The size of each type of cell found within developing galls of both species, from gall initiation to gall maturity were measured and compared. Cells in the galls of both species continue to increase in size throughout development; however, the cells comprising the galls induced by D. polita are significantly larger than those induced by D. nebulosa. Comparing the biologies and galls of these two species, demonstrates how niche partitioning has occurred. It also shows that striking differences in structures occur within the galls of closely taxonomically related species as a result of differences in adult phenology, oviposition strategies, egg placement, and environmental conditions such as moisture levels. Although it has been proposed by other authors that diversity in cynipid galls results from differentiation of tissues found in the outer parts of galls, such as cortex and epidermis, the present study indicates the reasons are more complex. Furthermore, it is apparent that many aspects of gall development and anatomy have been overlooked by previous researchers and a variety of ecological factors contribute to differences in gall structure. To further complicate the already complex series of events that occur over the course of gall development, galls of D. polita and D. nebulosa are inhabited and structurally modified by inquilines of the genus Periclistus. These insects are also cynipid wasps, and have evolved a close relationship with Diplolepis galls whereby they kill the inducer larvae, feed on gall cells, and change the developmental trajectory of attacked galls. Galls of D. polita and D. nebulosa are attacked by two undescribed, but gall-specific species of Periclistus. Here, the inquiline associated with the galls of D. polita is referred to as Periclistus 1 and the inquiline associated with galls of D. nebulosa is referred to as Periclistus 2. The purpose of this study was to histologically examine all phases of modification by the two species of Periclistus to establish the events that are developmentally unique to inquilines. Periclistus 1 and 2 are phenologically distinct as Periclistus 1 oviposits into immature galls of D. polita in late May soon after galls are induced, and Periclistus 2 oviposits into immature galls of D. nebulosa in July. Modified galls of D. polita differ from modified galls of D. nebulosa as they are significantly enlarged compared to normal galls. Periclistus 1 chambers are arranged around the periphery of the inner gall whereas modified galls of D. nebulosa are of a similar size to normal galls. Chambers of Periclistus 2 are evenly distributed throughout the inner gall. Periclistus 1 and 2-modified galls undergo four phases of development identified as the egg phase, gall enlargement, chamber formation, and maturation phases. Both Periclistus 1 and 2 oviposit into immature galls, killing the inducer larvae with their ovipositors, and then the presence of Periclistus eggs along the inner chamber surface cause changes in gall structure. Diplolepis-induced nutritive cells degrade and Diplolepis-induced parenchymatous nutritive cells enlarge. Galls become significantly enlarged compared to those inhabited by inducer larvae and then feeding by first-instar Periclistus larvae stimulates the differentiation and proliferation of Periclistus-induced parenchymatous nutritive cells and nutritive cells. Immature larvae of both species of Periclistus initially feed around the inner surface of the Diplolepis-induced chamber, and then restrict their feeding to one spot. This results in cell proliferation such that each larva becomes restricted to the centre of a bowl-shaped growth of cells. Continued proliferation causes Periclistus nutritive and parenchymatous nutritive cells to rise up and completely encase the larvae. As this is occurring in modified galls of D. polita, a layer of sclerenchyma, referred to here as the inquiline-induced primary sclerenchyma, differentiates and circumscribes the periphery of the entire gall. This does not occur in galls of D. nebulosa until maturity. In modified galls of both species, nutritive cells and parenchymatous nutritive cells appear in dense clusters throughout the inside surface of Periclistus chambers. Once modified galls enter the maturation phase, inquiline-induced primary sclerenchyma differentiates, circumscribing the periphery of galls of D. nebulosa. In addition, Periclistus 1 and 2-inhabited galls both develop a second layer of inquiline-induced sclerenchyma, known as secondary sclerenchyma, around each inquiline chamber. Secondary sclerenchyma cells in the walls of Periclistus chambers are smaller than primary sclerenchyma cells circumscribing the entire gall. Gall cells induced by Periclistus 1 are larger than those induced by Periclistus 2; however, gall cells induced by both species of Periclistus are larger than those of their host Diplolepis galls. Based on differences in phenology, gall development, and final gall structure, modified galls of D. polita and D. nebulosa are anatomically distinct with each species of Periclistus responsible for gall tissues that are species-specific. In addition, the developmental pattern of Periclistus-modified galls is distinct from that of Diplolepis galls, illustrating the level of control inquilines have over the tissues of their host galls. This thesis demonstrates the complex nature of the interrelationships between cynipid wasps of the genera Diplolepis and Periclistus and their host roses. Diplolepis are true gall inducers that have an intimate relationship with the genus Rosa and there are many attributes of the genus Rosa that have contributed to the success of Diplolepis and allowed for their extensive radiation and divergence in their galls. Similarly, Periclistus inquilines have an intimate relationship with Diplolepis and the rose hosts. Periclistus have evolved the ability to manipulate rose tissues that have previously been under the influence of Diplolepis. Based on two species of inquilines examined in this thesis, Periclistus have also evolved an array of phenologies and modification strategies and like the developmental patterns of the Diplolepis, the developmental trajectories of Periclistus are also species-specific. This project has shown that the histological approach to studying cynipid galls, as well as those occupied by Periclistus inquilines, is highly rewarding and contributes to our overall understanding of these fascinating insects.
An integrative approach to distinguishing taxonomically challenging microhymenoptera: Eurytomidae (Hymenoptera: Chalcidoidea) associated with cynipid galls on rose.
(Laurentian University of Sudbury, 2013-07-31) Zhang, Yuanmeng Miles
iii Abstract Cynipid wasps of the genus Diplolepis Geoffrey induce galls exclusively on roses. These galls are susceptible to attack by various hymenopteran parasitoids, the most common of which are members of the family Eurytomidae, with 10 described species having been recorded in association with rose galls in Canada. Because of their small size, sexual dimorphism, morphological plasticity and poorly known biology, species identification of eurytomids is often uncertain. This thesis focused on identifying the eurytomids associated with the galls of the 14 native species of Diplolepis in Canada, testing species limits using a combination of morphological, mitochondrial DNA cytochrome c oxidase I (COI), ecological and geographical data. Six morphospecies were identified using morphological characters, while molecular data identified eight haplogroups. COI sequences identified one species of Tenuipetiolus Bugbee and seven species of Eurytoma Illiger, all associated with galls induced by Diplolepis in Canada. Inconsistencies were observed when compared to morphospecies, including four haplogroups within the genus Eurytoma that were overlooked by morphological studies. The morphospecies Eurytoma acuta Bugbee is a junior synonym of Eurytoma discordans Bugbee; however, the high intraspecific genetic divergences suggest the existence of a species complex. Two geographically sympatric but genetically distinct haplogroups were found within the morphospecies Eurytoma spongiosa Bugbee, “E. spongiosa 2” being a new species that was previously overlooked. An identification key along with (re)descriptions of all identified species was provided. This integrative taxonomy approach confirmed the oligophagous nature of most eurytomids, and provides new insight into the life history strategies of these parasitoids.
Analysis of RBM5 and RBM10 expression throughout H9C2 skeletal and cardiac muscle cell differentiation.
(Laurentian University of Sudbury, 2013-07-31) Loiselle, Julie Jennifer
RNA Binding Motif (RBM) domain proteins RBM5 and RBM10 have been shown to influence apoptosis, cell cycle arrest and splicing in transformed cells. In this study, RBM5 and RBM10 were examined in non-transformed cells in order to gain a wider range of knowledge regarding their function. Expression of Rbm5 and Rbm10, as well as select splice variants, was examined at the mRNA and protein level throughout H9c2 skeletal and cardiac myoblast differentiation. Results suggest that Rbm5 and Rbm10 may (a) be involved in regulating cell cycle arrest and apoptosis during skeletal myoblast differentiation and (b) undergo post-transcriptional or translational regulation throughout myoblast differentiation. All in all, the expression profiles obtained in the course of this study will help to suggest a role for Rbm5 and Rbm10 in differentiation, as well as possible differentiation-specific target genes with which they may interact.
Un modèle d’étude in vitro de la réversion tumorale du cancer du col utérin dû aux infections par le virus de papillome humain à haut risque (VPH 16 et 18)
(Laurentian University of Sudbury, 2013-10-09) Nomenjanahary, Clara Ernestine
La réversion tumorale est un processus de transformation cellulaire peu fréquent qui s’explique par le rétablissement du contrôle de la croissance cellulaire aboutissant au phénotype cellulaire normal. Plusieurs agents sélectifs (virus, produits chimiques, interféron) peuvent être utilisés pour provoquer ce phénomène. L’efficacité de ces thérapies dépend de l’agressivité des cellules à traiter et les gènes qui sont bloqués. Les cellules HeLa et SiHa sont des lignées cellulaires utilisées fréquemment comme modèle in vitro pour étudier le cancer du col utérin. Ces deux lignées cellulaires comportent des oncogènes E6 et E7 du virus du papillome humain (VPH) à haut risque de type 18 pour les cellules HeLa et de type 16 pour les cellules SiHa. Les oncoprotéines virales E6 et E7 bloquent les protéines suppresseurs de tumeur p53 et pRb respectivement ce qui entraîne la transformation en cellules cancéreuses. La réactivation de la protéine p53 et/ou de la protéine pRb ou d’autres types de protéines effectuée par des agents sélectifs oncosuppressifs peut renormaliser le cycle cellulaire. L’étude proposée pour cette thèse vise à étoffer la littérature scientifique afin d’expliquer la faisabilité d’établir un modèle in vitro qui serait exploité pour 1) déterminer si la réversion tumorale a lieu de manière spontanée dans les cellules HeLa et SiHa, 2) comprendre les effets de différentes thérapies pouvant entraîner la réversion tumorale des cellules cancéreuses du col utérin et 3) comprendre le mécanisme d’action des thérapies oncosuppressives dans le contexte de la réversion tumorale du cancer du col utérin.
Liposomal clarithromycin delivery for the treatment of pseudomonal lung infection in cystic fibrosis.
(Laurentian University of Sudbury, 2013-10-29) Alhajlan, Mai Mohsen A.
The pulmonary infection with Pseudomonas aeruginosa is considered as one of the main causes of health deterioration in cystic fibrosis patients (CF). Efficient management of P. aeruginosa in CF remains difficult mainly with the emergence of multidrug-resistant strains leading ultimately to death. There is a pressing need for new approaches to control these Pseudomonal infections. Current studies on the antimicrobial efficacy of liposomal antibiotics have shown conflicting results. We sought to assess whether the incorporation of clarithromycin into liposomes could improve its antibacterial activity against clinical isolate of Pseudomonas aeruginosa from CF patients. Different formulations of liposomal clarithromycin were prepared, characterized and their antibacterial activities against resistant strains of P. aeruginosa were investigated. These formulations reduced the biofilm formation, the virulence factors production and the bacterial motilities compared to free drug. The therapeutic importance of liposome containing macrolides in the management of experimental pseudomonal lung infection in animals is warranted.
Physical and chemical changes in planarian and non-living aqueous systems from exposure to temporally patterned magnetic fields
(Laurentian University of Sudbury, 2013-11-11) Murugan, Nirosha J.
Planarian maintained in spring water and exposed for two hours to temporally patterned, weak (1 to 5 μT) magnetic field in the dark displayed diminished mobility that simulated the effects of morphine and enhanced this effect at concentrations associated with receptor subtypes. A single (5 hr) exposure to this same pattern following several days of exposure to a very complex patterned field in darkness dissolved the planarian and was associated with an expansion of their volume. Spectral power density analyses of direct measurements of the spring water only following exposure to this field in darkness showed emission spectra that were displayed from control conditions by ~10 nm and associated with an energy increment of ~10-20 J. This value is an intrinsic solution for the physical properties of the water molecule. “Shielding” the exposed water with plastic, aluminum foil or copper foil indicated that only the latter eliminated a powerful spike in photon emission around 280 nm. Continuous measurement of pH indicated that the slow shift towards alkalinity over 12 hours of exposure was associated with enhanced transient pH shifts of .02 units with typical durations between 20 and 40 ms. These results indicate that the appropriately patterned and amplitude of magnetic field that affects water directly could mediate some of the powerful effects displayed by biological aquatic systems.
Characterization of VR118 quinacrine derivative as a potential anticancer agent
(Laurentian University of Sudbury, 2014-03-17) Almnayan, Danah
The discovery and development of effective chemotherapeutic agents in the past few decades have immensely enhanced the treatment and management of human cancer. However, because these drugs are associated with adverse side effects, high genotoxicity, risk for secondary cancers and devastating effects on the patients’ immune system; the need for developing more effective anticancer agents remains. A priority Research shows that 9-aminoacridine (9AA) derivatives have substantial anticancer properties. The pharmacological properties of this agent are well characterized and this scaffold has been widely used to treat different diseases for decades. Quinacrine is a 9AA derivative, which was first discovered as an antimalarial compound in 1930’s and since then had been widely used in treating a variety of parasitic infections and demonstrated potential for cancer treatment. Importantly, the polypharmacology of Quinacrine makes it an attractive drug to treat a variety of cancers. Quinacrine acts by specifically targeting cellular signaling pathways that play an important role in cell survival. Given the distinctive cancer treating abilities of Quinacrine by specifically targeting cellular signaling pathways, it was the objective of this study to develop a compound that has similar properties as Quinacrine but has better efficacy and selectivity in targeting tumor cells. Therefore, for this project we created derivatives of 9AA compound using hybrid pharmapore approach and examined one of the derivatives of Quinacrine compound named VR118. After performing a series of experiments to test the efficacy and selectivity of the Quinacrine derivative VR118, I came to the conclusion that VR118 is highly effective in treating cancer cells and have the potential to selectively target cancer cells without causing severe harm to normal cells at concentrations applicable for malignant cell lines. This report discusses the efficacy and selectivity of VR118 compound in targeting cellular signaling pathways and the mechanisms through which VR118 kills cancer cells.
The introduction of native forest floor plant species in to the industrially disturbed forests of Sudbury, Ontario, Canada
(Laurentian University of Sudbury, 2014-03-17) Santala, Kierann R.
This study investigated the transplantation of understory plants within the Cu-Ni smelterdamaged urban forest of Sudbury, Ontario, Canada, to increase plant biodiversity in an area where natural colonization of understory species is delayed. The goal of my study was to evaluate establishment of 16 m2 vegetation mats along a gradient of smelter disturbance and to relate successful establishment to abiotic and biotic site characteristics. Specific investigations were conducted to determine whether soil quality influenced root growth and transplant establishment. Variables associated with smelter emissions and soil temperature were the best predictors of successful transplant establishment of understory plant species, but relationships were species specific. Also, root growth was not limited to organic soils of the transplant mat and roots were able to grow into receptor site soil. Knowledge of environmental factors influencing establishment will help to determine site locations and to select species to introduce when transplanting understory species in future reclamation projects.
The long road ahead: understanding road-related threats to reptiles and testing if current mitigation measures are effective at minimizing impacts
(Laurentian University of Sudbury, 2014-03-17) Baxter-Gilbert, James H
Reptile populations are suffering substantial global losses and roads are identified as one of the leading threats to their persistence. Currently, efforts to mitigate this threat are being implemented with various levels of success. I studied the effectiveness of exclusion structures (i.e., fencing) at preventing reptiles from gaining access to the road, and reducing road mortality. I also examined if population connectivity structures (i.e., ecopassages) were effective at reducing habitat and population fragmentation and allowing individuals to access habitats, resources, and mates on both sides of a major road (4 lane highway). I found that the fence was ineffective at preventing reptiles from gaining access to the road; however, reptiles were observed using the ecopassages to cross the road. Behavioural trials testing painted turtles’ (Chrysemys picta) willingness to use an ecopassage demonstrated that refusal was twice more likely than use of an ecopassage. I also examined the potential for roads to pose a physiological threat to roadside populations of reptiles by examining corticosterone (CORT), a stress hormone linked to negative health effects in cases of elevated levels over the long-term. To assess if individuals living near a major road had higher CORT levels than individuals from a less impacted population, I developed a novel means of measuring CORT from painted turtle claws in partnership with Dr. Gabriela Mastromonaco (Toronto Zoo). With long-term CORT levels considered as a proxy for chronic physiological stress, I did not find evidence that populations near roads had altered stress levels. However, this seminal study will provide the framework for further examination of more species, including species-at-risk, and a better understanding of effects of anthropogenic environments on wildlife health. As road ecologists strive to expand our understanding of the threats roads pose to reptiles, it is important that this field spans multiple disciplines, so that we can both understand the direct and indirect threats that roads cause and develop effective mitigation that preserves biodiversity within our anthropogenic landscape.
Life-history trade-offs in Northern leopard frog (Lithobates [Rana] Pipiens) tadpoles: interactions of trace metals, temperature, and ranavirus
(Laurentian University of Sudbury, 2014-03-19) Leduc, Joël
Emerging infectious diseases, pollution and climate change are associated with amphibian extinction events worldwide; however, direct causation is often obscured by the interactions of these stressors. Elucidating the possible synergies between metal contamination and disease is, therefore, critical in advancing our knowledge of the co-evolutionary mechanisms in host-pathogen systems and helping with the ability to better forecast the spread of diseases in metal-stressed environments. Additionally, increasing ecotoxicological research has improved our understanding of the complex influence trace metals may have on the physico-chemical nature of aquatic systems; however, the discrepancy in concentration-response within the toxicological literature makes it difficult to accurately define the range of toxicity, often due to the variability in media used in experimentation. The first chapter of this thesis reports an evaluation of copper, nickel and copper/nickel concentrations on several Northern Leopard Frog (Lithobates [Rana] pipiens) larvae life history traits within field collected smelting effluent water. Overall, results indicated that copper had a stronger negative impact on survival than nickel. However, tadpoles exposed to copper displayed increased growth and developmental patterns while those exposed to nickel demonstrated opposing life history traits. These results indicate that tadpoles are displaying different fitness strategies, in terms of survival and life history, in the presence of increased copper and/or nickel stress.
rRNA disruption: a predictive marker of response to taxane chemotherapy
(Laurentian University of Sudbury, 2014-03-19) Narendrula, Rashmi
A recent clinical trial for locally advanced breast cancer patients treated with epirubicin and docetaxel prior to surgery reported significant dose-dependent reductions in tumour RNA integrity values which correlated with pathological complete response. The purpose of the present study was to assess whether similar chemotherapy-dependent alterations in RNA integrity could occur in vitro and to assess its relationship, if any, to apoptosis. Treatment of wildtype A2780 ovarian carcinoma cells with taxanes resulted in dose- and time-dependent RNA degradation, identified as several unique bands on electropherograms having mobilities lower than the 28S and 18S rRNAs. We refer to this chemotherapy-dependent generation of aberrant RNA bands on electropherograms as “RNA disruption”. RNA disruption was found to be temporally associated with the induction of apoptosis, as determined by the appearance of a sub G1 peak of DNA content, positive annexin-V staining, and both PARP-1 and caspase-3 cleavage. Treatment of cells with a caspase-3 inhibitor resulted in a significant reduction in rRNA disruption, suggesting the involvement of caspase-3 or related caspases in RNA disruption. In contrast, docetaxel-dependent rRNA disruption was absent when docetaxel was administered to docetaxel-resistant A2780DXL cells, indicating that changes in RNA integrity may possibly differentiate between responsive and non-responsive tumours in cancer patients.
Population distribution and seasonal resource selection by elk (Cervus Elaphus) in Central Ontario
(Laurentian University of Sudbury, 2014-04-14) McGeachy, David N. C.
Understanding population structure and resource selection are essential for wildlife management and conservation. I assessed the population structure and resource selection of elk (Cervus elaphus) in central Ontario. I used fuzzy and hierarchical cluster analyses to elucidate elk population structure based on spatial data collected from 41 radio-collared elk. I assessed impacts of habitat quality on space use using the minimum convex polygon (MCP) and fixed kernel methods. I evaluated resource selection by elk in winter, spring, summer, and fall, from December 2011 to August 2013, using resource selection functions (RSF’s). I used a generalized linear mixed model (GLMM) to evaluate resource selection functions and used Akaike information criterion (AICc ) to select the best model of 20 candidate models constructed a priori. Models included parameters representing resources known to be important to elk: elevation, aspect, slope, distance to roads and water, and habitat. Both fuzzy and hard clustering indicated that elk in Central Ontario occur in a metapopulation that includes 5 subpopulations. The largest cluster consisted of a core group of 22 radio-collared elk located in Burwash with several satellite subpopulations spread along a 50km long north-south axis and a small subpopulation to the west located in Worthington. Survival rates among subpopulations were similar ranging from 0.71 to 0.83; however, anthropogenic causes of mortality were predominant only in the Burwash subpopulation. Space use and density of elk differed between core and satellite subpopulations. Resource selection by elk differed by time of day and season. In all seasons, elk selected open habitats at night and more forested areas during the day. Elk avoided areas close to roads in spring, but selected them in winter at night. Elk selected higher elevations in winter and for south facing slopes in spring and fall. Elk displayed strong crepuscular activity patterns in all seasons; however, movements were limited in winter. Understanding population structure is important in order to develop appropriate management plans. My results support the conclusion that population structure can be reliably assessed using spatial data. Resource selection is a dynamic process that changes with seasons, as well as animal activity across the diel period. Resource selection should include time of day in order to obtain a complete picture of resources important to a particular species and to support the conservation of habitats used for various animal activities.
Effects of liming on soil respiration, fungi diversity and abundance in a metal-contaminated region in Northern Ontario
(Laurentian University of Sudbury, 2014-05-16) Goupil, Kassandre
At present, little is known concerning the fungi communities inhabiting the Greater Sudbury Region. This study aimed at identifying the fungal species and abundance in limed and unlimed areas contaminated with metals. Samples were collected from the LFH soil layer from Wahnapitae Hydro-Dam, Daisy Lake, Kingsway, Kelly Lake, Hagar, Onaping Falls and Capreol. Limed and unlimed areas were compared for soil metals, pH, fungi diversity, abundance and seasonal soil respiration. Fungi from soil samples were cultured using Sabouraud Dextrose Agar and Malt Extract Agar. A total of 52 fungi species from 34 genera were identified. There was a significantly higher fungal diversity in the limed areas compared to the samples from unlimed sites based on SDA medium data. Fungi abundance followed the same trend. Significantly higher soil respiration rates were recorded for limed sites compared to unlimed sites. Summer soil respiration rates correlated (r = 0.50) with total fungal abundance.
Comparative analysis of soybean (glycine max) accessions using inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers
(Laurentian University of Sudbury, 2014-05-16) Alamri, Sarah
Soybean (Glycine max) is an important crop in the world in terms of total production and usage. It is also among the least diverse species. The main objectives of the present study were 1) to determine differences between ISSR and RAPD marker systems in detecting genetic variation in soybeans and 2) to identify and characterize accession- diagnostic molecular markers in G. max accessions. Genomic DNAs from 108 G. max accessions from 11 different gene pools were analyzed using several ISSR and RAPD primers. The levels of polymorphic loci detected with the two marker systems were in general moderate and similar.. Overall, 82% of genetic distance values were above 0.40 based on ISSR analysis. However, RAPD data revealed that the accessions from different countries are closely related with 64% genetic distance values below 0.40. The dendrograms constructed with ISSR data revealed that the South Korean accessions formed an out-group while the RAPD analysis showed that accessions from Sweden were separate from the other 10 gene pools. One variety-diagnostic marker generated with ISSR 5 primer was identified in the accession Kao Chien Tao from China. This marker was cloned, and sequenced. Although RAPD and ISSR marker systems detected similar levels of genetic variability, they target different regions of the soybean genome, resulting in different clustering of the 11 gene pools indicating different genetic relatedness among them. This finding demonstrates the usefulness of both marker systems in assessing diversity and relatedness among Glycine max gene pools.
The effect of Uncaria Tomenosa on the murine melanoma cell line, B16-BL6
(Laurentian University of Sudbury, 2014-09-02) Alfarteesh, Hajer
Uncaria tomentosa, commonly known as Cat’s claw, is a medicinal plant native to Peru. It has been used for decades in the treatment of various inflammatory disorders. Treatment with Uncaria tomentosa has been shown to have effective anti-inflammatory activities. Recent studies show that treatment of cells with extracts of Uncaria tomentosa can inhibit the MAP kinase, Akt, and Wnt signaling pathways, suggesting it has specific anticancer therapeutic properties. Previous work from our laboratory has shown that the effect of Uncaria tomentosa on the monocyte-like THP-1 cell line can block activation of these immune cells. We are now investigating the effect of the Uncaria tomentosa as an anti-cancer therapy. We have shown that Uncaria tomentosa can inhibit the growth of cell cultures and can induce apoptosis in the murine melanoma cell line B16- BL6. Extracts of Uncaria tomentosa with 70% ethanol were more efficient at inducing apoptosis than aqueous extracts. Apoptosis induction was evident as early as 24h after treatment and almost all cells treated with the ethanolic extract of Uncaria tomentosa were apoptotic by 72h. Treatment with Uncaria tomentosa caused an increase in DNA fragmentation (TUNEL assay), caspase-3 cleavage, sub G1 peaks in flow cytometry, and apoptotic morphology. Our experimental results indicate that Uncaria tomentosa can effectively kill melanoma cancer cells in vitro, in a dose-dependent manner, by enhancing apoptosis.
Energy-producing ability of bacteria under oxidative stress
(Laurentian University of Sudbury, 2014-10-07) Appanna, Varun P.
Nitrosative stress is caused by reactive nitrogen species (RNS) and is toxic to most organisms. RNS are generated by the immune system to combat infectious microbes and are known to impede O2-dependent energy production. The goal of this study was to elucidate alternative adenosine triphosphate (ATP)-forming pathways that enable the model bacterium Pseudomonas fluorescens to survive a nitrosative challenge in a fumarate medium. Fumarate was metabolized by fumarase C (FUM C), a RNS-resistant enzyme and fumarate reductase (FRD). The enhanced activities of pyruvate phosphate dikinase (PPDK), adenylated kinase (AK) and nucleoside diphosphate kinase (NDPK) provided an effective route to ATP production by substrate-level phosphorylation (SLP), a process that does not require O2. The metabolic networks utilized to neutralize nitrosative stress reveal potential target against RNS-tolerant bacteria and a route to the conversion of fumarate into succinate, a value-added product.
Developing manufactured soils for reclamation of mined land in the boreal forest ecosystem
(Laurentian University of Sudbury, 2014-10-08) Watkinson, Autumn L.D.
The purpose of this study was to manufacture a cover soil that will be suitable to create ‘cover islands’ of native boreal vegetation for reclamation of large mine rock piles generated through open-pit mining activities in the Boreal Shield region north of Lake Superior. Multiple Technosols were manufactured from blends of mill derived organic residuals and finely crushed mine rock. A ten week growth study assessing the performance of the Technosols as growth media for annual ryegrass demonstrated that blends of at least 50% woody residuals and a mixture of finely crushed mine rock could be used to produce a viable growth media. Reclamation plots were constructed in a field setting using two new Technosols manufactured in ratios of 40 and 80% organics using woody residuals and mixed mine rock, applied to 30 or 60 cm depths over a coarse mine rock pile to simulate ‘vegetation islands’. Soil microclimate data and soil pore-water samples collected over one annual cycle demonstrate that increasing organic matter increased soil moisture and concentration of bioavailable plant nutrients. Increasing depth of plots enabled development of a reservoir of available plant moisture below the rooting zone, but did not increase moisture in surface soils. Low survival rates of tickle grass and green alder can mostly likely be attributed to low moisture availability in the surface soils at the time of planting. Technosols composed of 80% woody residuals and deposited to a 60 cm depth could be appropriate for use in reclamation if surface moisture is increased.

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