6 resultados para 229

em Brock University, Canada


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Brock Alumnus Pat Beard was the University Secretary during the 1980's. He was a member of BUSU while a student at Brock.

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The nucleotide sequence of a genomic DNA fragment thought previously to contain the dihydrofolate reductase gene (DFR1) of Saccharomyces cerevisiae by genetic criteria was determined. This DNA fragment of 1784' basepairs contains a large open reading frame from position 800 to 1432, which encodes a enzyme with a predicted molecular weight of 24,229.8 Daltons. Analysis of the amino acid sequence of this protein revealed that the yeast polypep·tide contained 211 amino acids, compared to the 186 residues commonly found in the polypeptides of other eukaryotes. The difference in size of the gene product can be attributed mainly to an insert in the yeast gene. Within this region, several consensus sequences required for processing of yeast nuclear and class II mitochondrial introns were identified, but appear not sufficient for the RNA splicing. The primary structure of the yeast DHFR protein has considerable sequence homology with analogous polypeptides from other organisms, especially in the consensus residues involved in cofactor and/or inhibitor binding. Analysis of the nucleotide sequence also revealed the presence of a number of canonical sequences identified in yeast as having some function in the regulation of gene expression. These include UAS elements (TGACTC) required for tIle amino acid general control response, and "TATA H boxes as well as several consensus sequences thought to be required for transcriptional termination and polyadenylation. Analysis of the codon usage of the yeast DFRl coding region revealed a codon bias index of 0.0083. this valve very close to zero suggestes 3 that the gene is expressed at a relatively low level under normal physiological conditions. The information concerning the organization of the DFRl were used to construct a variety of fusions of its 5' regulatory region with the coding region of the lacZ gene of E. coli. Some of such fused genes encoded a fusion product that expressed in E.coli and/or in yeast under the control of the 5' regulatory elements of the DFR1. Further studies with these fusion constructions revealed that the beta-galactosidase activity encoded on multicopy plasmids was stimulated transiently by prior exposure of yeast host cells to UV light. This suggests that the yeast PFRl gene is indu.ced by UV light and nlay in1ply a novel function of DHFR protein in the cellular responses to DNA damage. Another novel f~ature of yeast DHFR was revealed during preliminary studies of a diploid strain containing a heterozygous DFRl null allele. The strain was constructed by insertion of a URA3 gene within the coding region of DFR1. Sporulation of this diploid revealed that meiotic products segregated 2:0 for uracil prototrophy when spore clones were germinated on medium supplemented with 5-formyltetrahydrofolate (folinic acid). This finding suggests that, in addition to its catalytic activity, the DFRl gene product nlay play some role in the anabolisln of folinic acid. Alternatively, this result may indicate that Ura+ haploid segregants were inviable and suggest that the enzyme has an essential cellular function in this species.

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An unsigned, undated draft of a resolution by Mechanics in the Kingston, Ont. area responding to the availability of cheap convict labour. The resolution proposes to shift convict labour to the Marmora, Ont. iron fields.

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Survey map of the Second Welland Canal created by the Welland Canal Company showing the canal in the Thorold Township between Port Robinson and Welland. Identified structures and features associated with the Canal include the towing path, back ditches, and the waterway itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include several road allowances, two bridges(Northern most bridge would be the Quaker Bridge), Spoil Bank, two ponds, and several fences. Properties and property owners of note are: Lot 229, and Jacob Silverthorne.

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Survey map and description of Jonathan Silverthorn's land created by The Welland Canal Company. Included is a written description of the land along with a drawing of the land. The lands surveyed include lots 229 and 230. The land was first surveyed in 1830, then again in 1834, by George Keefer. The original survey only included the feeder and resevoir and wood land, whereas the second survey shows all lands owned by Silverthorn. The land totals 19.2 acres, 2 roads and 32 perches. The land is broken down as follows; 7.6 acres cleared land, canal and towpath, 6.6 acres reservoir - Michael Silverthorn, 5 acres woodland. Surveyor notes are seen in pencil and red pen on the map.See also page 138.

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Guest editorial for themed issue on international activities of Canadian librarians.