10 resultados para raptor-accumulated avifauna
em Brock University, Canada
Resumo:
Growth stimulation of Avena coleoptile tissue by indoleacetic acid (IAA) and fusicoccin (FC) was compared by measuring both their influence on RNA and protein synthesis during IAA or FC stimulated growth. FC stimulated growth more than IAA during the initial four hour exposure, after which the growth rate gradually declined to the control rate. FC, but not IAA, increased the uptake of 3H-Ieucine into tissue and the specific radioactivity of extracted protein. Cycloheximide inhibited the incorporation of 3H-Ieucine into protein by approximately 60% to 70% in all cases. In the presence of cycloheximide 3H-radioactivity accumulated in FC-treated tissue, whereas IAA did not seem to influence 3H-accumulation. These results suggest that FC stimulated leucine uptake into the tissue and that increased specific activity of coleoptile protein is due to increased leucine uptake, not an increased rate of protein synthesis. There was no measurable influence of IAA and/or FC on RNA and protein synthesis during the initial hours of a growth stimulation. Inhibitors of RNA and protein synthesis, actinomycin D and cycloheximide, respectively, severely inhibited IAA enhanced growth but only partially inhibited FC stimulated growth. The data are consistent with suggestions that a rapidly turning over protein participates in IAA stimulated growth, and that a continual synthesis of RNA and proteins is an absolute requirement for a long term growth response to IAA. On the contrary, FC-stimulated growth exhibited less dependency on the transcription and translation processes. The data are consistent with proposals suggesting different sites of action for FC and IAA stimulated growth. l?hen compared to CO2-free air, CO2 at 300 ppm had no significant influence on coleoptile growth and protein synthesis in the presence or absence of lAA or FC. Also, I mM malate, pH 6.0 did not influence growth of coleoptiles in the presence or absence of lAA. This result was obtained despite reports indicating that 300 ppm CO2 or I mM malate stimulates growth and protein synthesis. This lack of difference between CO2-treated and untreated tissue could indicate either that the interstitial space CO2 concentration is not actually different in the two treatments due to significant endogenous respiratory CO2 or else the data would suggest a very loose coupling between dark CO2 fixation and growth. IAA stimulated the in vivo fixation of 14c-bicarbonate (NaHI4c03) by about 25% and the addition of cycloheximide caused an inhibition of bicarbonate fixation within 30 min. Cycloheximide has also been reported to inhibit IAA-stimulated H+ excretion. These data are consistent with the acid growth theory and suggest that lAA stimulated growth involves dark CO2 fixation. The roles of dark CO2 fixation in lAA-stimulated growth are discussed.
Resumo:
In light of the heavy reliance of the people of the Niagara Peninsula on the T\\'elve Mile Creek (TMC) watershed for recreational activities and for municipal and industrial uses ( e.g., drinking water, shipping and discharge of effluents), it was deemed prudent to assess the envirol1tnental health of the system by analysing the sediments total and exchangeable metal, and TPH contents. The MOEE has set guidelines with limits for the protection and management of aquatic sediments, and the sediments from the headwaters of the TMC have total metal and TPH (subset of O&G) contents well below the lower provincial limits. Areas of environmental concern where total metal contents in sediments, either individually or collectively, exceed the guideline, are the south side of Lake Gibson, the Old WeIland Canal, a segment of TMC just south of the QEW and Martindale Pond. The total metal content of sediments does not in all instances identify areas of biological concern. Instead, it has been found that the exchangeable metal fraction of sediments is a better indicator of metal availability and thus potential accumulation in organisms. In some instances, the exchangeable metal fraction agrees with the total metal fraction defining areas of environmental concern, but it does vary from site to site reflecting the natural variability of the ambient environment. Overall, the exchangeable metal fraction of sediments appears to be a better indicator of anthropogenic pollution and ecosystem impact. A histochemical study of Anodon.ta sp., Elliptio sp. and zebra mussels (Dreissena polyn'101pha) was done in conjunction with passive biomonitoring of zebra and quagga mussels (Dreissena bugensis) from the Twelve Mile Creek watershed and Lake 51. Clair (Jeanette's Creek, Chatham, Ontario). The highest concentrations of divalent metals such as Cu, Ni, Cd, and Zn, and trivalent Al appear to accumulate in gill and kidney tissues. Metal contents of organ tissues in Anodonta sp. vary with size class. Organ metal content varies among size classes, thus requiring consideration of size in biomonitoring studies. Shucked zebra and quagga mussel tissues, exhibited similar size class to Al content trends. In addition they reflected the Al content trends of top (approximately 10 cm) most sediments in the Twelve Mile Creek watershed. Quagga mussels appear to have higher Al concentrations than zebra mussels, thus suggesting that quagga mussels may be better passive biomonitors of AI. Cd content in zebra mussel tissues, seemed to increase with size class trends. This was not demonstrated in the quagga mussel tissues. This suggests that Cd may be regulated by quagga mussels and not by zebra mussels, and that zebra mussels may be better passivebiomonitors of Cd than are quagga mussels. Zebra mussel, quagga mussel, Anodonta sp., and Elliptio sp. were used in a two part, active (translocated) biomonitoring study of the Twelve Mile Creek watershed. There was no statistical difference in death rates between zebra and quagga mussels after 65 days of biomonitoring. However there does appear to be a difference of death rates between sites. Unfortunately the data base did not permit us to differentiate between sites. Relative to Port Colborne Harbour (Port Colborne, Ontario), the Twelve Mile Creek watershed appears to be elevated in bioavailable AI. An area near the terminus of the Twelve Mile Creek appears to be an area of environmental concern since mussels seemed to have accumulated relatively large concentrations of Cd, Zn, and Pb. In addition to possible metal loading from a nearby outfalls, or possible upstream outfalls, road salt runoff from storm sewers may have contributed to metal accumulation through cation exchanges processes. Similar trends in cumulative quagga mussel metal concentrations during the two time periods (65 and 159 days), suggest that quagga mussels may reach equilibrium within 65 days of translocation. Differences in bioaccumulated metal concentrations of the two dreissenid species demonstrate that active biomonitoring studies must use a variety of organisms to adequately assess the environmental situation of specific waterways and/or bodies.
Resumo:
Over the last two decades, the prevalence of obesity in the general population has been steadily increasing. Obesity is a major issue in scientific research because it is associated with many health problems, one of which is bone quality. In adult females, adiposity is associated with increased bone mineral density, suggesting that there is a protective effect of fat on bone. However, the association between adiposity and bone strength during childhood is not clear. Thus, the purpose of this study was to compare bone strength, as reflected by speed of sound (SOS), of overweight and obese girls and adolescents with normal-weight age-matched controls. Data from 75 females included normal-weight girls (G-NW; body fat:::; 25%; n = 21), overweight and obese girls (GOW; body fat ~ 28%; n = 19), normal-weight adolescents (A-NW, body fat:::; 25%; n = 13) and overweight and obese adolescents (A-OW; body fat ~ 28%; n = 22). Nutrition was assessed with a 24-hour recall questionnaire and habitual physical activity was measured for one week using accelerometry. Using quantitative ultrasound (QUS; Sunlight Omnisense™), bone SOS was measured at the distal radius and mid-tibia. No differences were found between groups in daily total energy, calcium or vitamin D intake. However, all groups were below the recommended daily calcium intake of 1300 mg (Osteoporosis Canada, 2008). Adolescents were significantly less active than girls (14.7 ± 0.6 vs. 6.3 ± 0.6% active for G and A, respectively). OW accumulated significantly less minutes of moderate-to-very vigorous physical activity per day (MVPA) than NW in both age groups (114 ± 6 vs. 57 ± 5 min/day for NW and OW, i respectively). Girls had significantly lower radial SOS (3794 ± 87 vs. 3964 ± 64 mls for G-NW and A-NW, respectively), and tibial SOS (3678 ± 86 vs. 3878 ± 52 mls for G-NW and A-NW, respectively) than adolescents. Radial SOS was similar in the two adiposity groups within each age group. However, tibial SOS was lower in the two overweight groups (3601 ± 75 mls vs. 3739 ± 134 mls for G-OW and A-OW, respectively) compared with the age-matched normal-weight controls. Body fat percentage negatively correlated with tibial SOS in the study sample as a whole (r = -0.30). However, when split into groups, percent bo~y fat correlated with tibial SOS only in the A-OW group (r = -0.53). MVPA correlated with tibial SOS (r = 0.40), once age was partialed out. In conclusion, in contrast withthe higher bone strength characteristic of obese adult women, overweight and obese girls and adolescents are characterized by low tibial bone strength, as assessed with QUS. The differences between adiposity groups in tibial SOS may be at least partially due to the reduced weight-bearing physical activity levels in the overweight girls and adolescents. However, other factors, such as hormonal influences associated with high body fat may also playa role in reducing bone strength in overweight girls. Further research is required to reveal the mechanisms causing low bone strength in overweight and obese children and adolescents.
Resumo:
The Loyal Orange Association of British America is a Protestant fraternal society. The Loyal Orange Association originated in Ulster, Ireland during the late eighteenth century. Its purpose was to promote Protestant rights and privileges. The association was exclusively Protestant, fraternal, democratic, and benevolent. Orange principles were brought to Upper Canada by Protestant Irish settlers after 1815. The first Canadian Orange Lodge was formally established in Brockville, Leeds County, 1830. By the late 19th and early 20th century, the Loyal Orange Association of British North America had gained considerable popularity and political influence. Many prominent politicians, including several prime ministers, were members. Orangemen were particularly concerned with issues such as separate school funding, language rights, immigration, religious freedom and conscription. Further, they demanded the execution of Louis Riel and opposed the Jesuits Estates settlement. Administrative sketch courtesy Archives of Ontario.
Resumo:
The Welland Canals Society was a coalition of business, tourism, heritage, and recreational groups that joined with the Regional Government in 1986 to promote the redevelopment of the Welland Canals Corridor. The mandate of the Society was to provide leadership and assistance to the public and private sectors in achieving heritage-sensitive and tourism/recreation-related economic development in the Welland Canals Corridor. The Society folded in 1991 due to government funding cuts.
Resumo:
Icewine is a sweet dessert wine fermented from the juice of grapes naturally frozen on the vine. The production of Icewine faces many challenges such as sluggish fermentation, which often yields wines with low ethanol, and an accumulation of high concentration of volatile acidity, mainly in the form of acetic acid. This project investigated three new yeast strains as novel starter cultures for Icewine fermentation with particular emphasis on reducing acetic acid production: a naturally occurring strain of S. bayanus/S. pastorianus isolated from Icewine grapes, and two hybrids between S. cerevisiae and S. bayanus, AWRI 1571 and AWRI 1572. These strains were evaluated for sugar consumption patterns and metabolic production of ethanol, glycerol and acetic acid, and were compared to the performance of a standard commercial wine yeast KI-VI116. The ITS rONA region of the two A WRI crosses was also analyzed during fermentations to assess their genomic stability. Icewine fermentations were performed in sterile filtered juice, in the absence of indigenous microflora, and also in unfiltered juice in order to mirror commercial wine making practices. The hybrid A WRI 1572 was found to be a promising candidate as a novel starter culture for Icewine production. I t produced 10.3 % v/v of ethanol in sterile Riesling Icewine fermentations and 11.2 % v/v in the unfiltered ones within a reasonable fermentation time (39 days). Its acetic acid production per gram sugar consumed was approximately 30% lower in comparison with commercial wine yeast K I -V 1116 under both sterile filtered and unfiltered fermentations. The natural isolate S. bayanus/S. pastorianus and AWRI 1571 did not appear to be suitable for commercial Icewine production. They reached the target ethanol concentration of approximately 10 % v/v in 39 day fermentations and also produced less acetic acid as a function of both time and sugar consumed in sterile fermentations compared to KI-V1116. However, in unfiltered fermentations, both of them failed to produce the target concentration of ethanol and accumulated high concentration of acetic acid. Both A WRI crosses displayed higher loss of or reduced copies in ITS rDNA region from the S. bayanus parent compared to the S. cerevisiae parent; however, these genomic losses could not be related to the metabolic profile.
Resumo:
Endonuclease G (EndoG) is a well conserved mitochondrial nuclease with dual lethal and vital roles in the cell. It non-specifically cleaves endogenous DNA following apoptosis induction, but is also active in non-apoptotic cells for mitochondrial DNA (mtDNA) replication and may also be important for replication, repair and recombination of genomic DNA. The aim of our study was to examine whether EndoG exerts similar activities on exogenous DNA substrates such as plasmid DNA (pDNA) and viral DNA vectors, considering their importance in gene therapy applications. The effects of EndoG knockdown on pDNA stability and levels of encoded reporter gene expression were evaluated in the cervical carcinoma HeLa cells. Transfection of pDNA vectors encoding short-hairpin RNAs (shRNAs) reduced levels of EndoG mRNA and nuclease activity in HeLa cells. In physiological circumstances, EndoG knockdown did not have an effect on the stability of pDNA or the levels of encoded transgene expression as measured over a four day time-course. However, when endogenous expression of EndoG was induced by an extrinsic stimulus (a cationic liposome transfection reagent), targeting of EndoG by shRNA improved the perceived stability and transgene expression of pDNA vectors. Therefore, EndoG is not a mediator of exogenous DNA clearance, but in non-physiological circumstances it may non-specifically cleave intracellular DNA regardless of its origin. To investigate possible effects of EndoG on viral DNA vectors, we constructed and evaluated AdsiEndoG, a first generation adenovirus (Ad5 ΔE1) vector encoding a shRNA directed against EndoG mRNA, along with appropriate Ad5 ΔE1 controls. Infection of HeLa cells with AdsiEndoG at a multiplicity of infection (MOI) of 10 p.f.u./cell resulted in an early cell proliferation defect, absent from cells infected at equivalent MOI with control Ad5 ΔE1 vectors. Replication of Ad5 ΔE1 DNA was detected for all vectors, but AdsiEndoG DNA accumulated to levels that were 50 fold higher than initially, four days after infection, compared to 14 fold for the next highest control Ad5 ΔE1 vector. Deregulation of the cell cycle by EndoG depletion, which is characterized by an accumulation of cells in the G2/M transition, is the most likely reason for the observed cell proliferation defect. The enhanced replication of AdsiEndoG is consistent with this conclusion, as Ad5 ΔE1 DNA replication is intimately related to cell cycling and prolongation or delay in G2/M greatly enhances this process. Furthermore, infection of HeLa with AdsiEndoG at MOI of 50 p.f.u./cell resulted in an almost complete disappearance of viable, adherent tumour cells from culture, whereas almost a third of the cells were still adherent after infection with control Ad5 ΔE1 vectors, relative to the non-infected control. Therefore, targeting of EndoG by RNAi is a viable strategy for improving the oncolytic properties of first generation adenovirus vectors. In addition, AdsiEndoG-mediated knockdown of EndoG reduced homologous recombination between pDNA substrates in HeLa cells. The effect was modest but, nevertheless demonstrated that the proposed role of EndoG in homologous recombination of cellular DNA also extends to exogenous DNA substrates.
Resumo:
Teachers can reflect on their practices by articulating and exploring incidents they consider critical to themselves or others. By talking about these critical incidents, teachers can make better sense of seemingly random experiences that occur in their teaching because they hold the real inside knowledge, especially personal intuitive knowledge, expertise and experience that is based on their accumulated years as language educators teaching in schools and classrooms. This paper is about one such critical incident analysis that an ESL teacher in Canada revealed to her critical friend and how both used McCabe’s (2002) narrative framework for analyzing an important critical incident that occurred in the teacher’s class.
Resumo:
The Woodruff Family Collection: From the time the Woodruff Family came to Canada from the United States in 1795, they took an active role in the forming of their communities both in a civic and social manner. This is evident through the documents contained in this collection. The Woodruffs played an active role in the battles fought in Upper Canada and they were an integral part of the Village of St. Davids. They were educated, business-minded and socially engaged. They accumulated much of their fortune through land dealings. Much of this collection focuses on Samuel DeVeaux Woodruff who was principally a businessman. His dedication to his work is shown through his numerous undertakings. He made his mark on the Niagara Peninsula through his work on the railways, roads, marsh land revisions, canals and the paper industry. He was also involved with the founding of the Long Point Company and he took control of building DeVeaux Hall down to the last detail. His offspring inherited his work ethic and his business acumen. The people who married into the Woodruff Family also possessed key social, political and business ties. Anne and Margaret Clement were from a staunch Loyalist background. Samuel Zimmerman was instrumental to the founding of Niagara Falls and Judge Samuel DeVeaux left behind a legacy for poor and homeless boys in Niagara Falls, New York. The Woodruff Family undoubtedly left a mark on the Niagara Peninsula. This collection brings to light many endeavours of the family and their varied contributions.
Chemical, biochemical, and molecular characterization of a low vindoline Catharanthus roseus mutant.
Resumo:
The Madagascar periwinkle (Catharanthus roseus) is the sole source of the anticancer drug vinblastine, which is formed via the coupling of monoterpenoid indole alkaloids (MIAs) catharanthine and vindoline. A mutant line of C. roseus (M2-1865) with an altered MIA profile was identified in a screen of 4000 M2 lines generated by ethylmethanesulfonate (EMS) chemical mutagenesis. While this line did not accumulate vinblastine due to reduced levels of vindoline within the leaves, significant levels of 2,3-epoxide derivatives of tabersonine accumulated on the leaf surface. Detailed nucleotide, amino acid, and enzyme activity analyses of tabersonine 3-reductase in the M2-1865 line showed that a single amino acid substitution (H189Y) diminished the biochemical activity of T3R by 95%. Genetic crosses showed the phenotype to be recessive, exhibiting standard Mendelian single-gene inheritance. The usefulness of EMS mutagenesis in elucidating MIA biosynthesis is highlighted by the results of this study.