Flore complète de la France et de la Suisse (comprenant aussi toutes les espèces de Belgique) pour trouver facilement les noms des plantes sans mots techniques : 5338 figures représentant les caractères de toutes les espèces... (5e éd. revue et corrigée) / par Gaston Bonnier,... et G. de Layens,...

Collection : La Végétation de la France, Suisse et Belgique. 1re partie

Amplification of the DFR1 gene in Saccaromyces cerevisiae

A new system was employed to study amplification of t,he DHF'R gene DFB,1 ) in Sa<,:;charoillYCB§. .Q~~Yi...S!i<;1~. . This system consists of a series of yeast strains containing a casset,te which encodes t he yeast, D..ERl gene ttghtly linked tjO a f usion of the yeast 1EU2. regulat,ory region wi tJ1 the LAQZ str ctural gene from E. cO.1-1 (,) . M. Clement , unpubl i,::;hed) . Th's casset;t e was shown t.o be integrat,ed int o a unj que chromosomal l ocati on in each strain . Yeast cells were se l ected for MTX-resistance and overproduction of ~ galac t osi d se ( B-gal ). Since the inserted DF'Rl and ~ACZ genes are independently regulated, it was thought that cel l s with this phenotype probably contain e d ampl if ications of the cassette. A lar ge variat ion in the f requn y o f MTX-resistance was found between the di ff e r ent str ains. These freqlen c ~ es r anged from about 2 x 10 - 7 fo r a population of cells containing the cassette integrated at, the BI J2.l gene in t,he middle of the long arm of chromosome V, to about 5 x 10-4 for a strain with the cassette i nserted in the r DNA cluster Abo It 85% of the MTX- res i stcmt iso l ates examined showed enhanced B·-gal act i v ity rel a t ive t o the parental strain . For the ma jorit y of strains, the mean B- gal activity in drug-r sistant clones was about 3 times that o f the parent following a single se l ect i on step . I n con t r ast, primary MTX-resistant derivat~ves of cells with the cassette inserted 3 at the rDNA cluster showed inc r eases in B- gal activity ranging from 9 - 14 f old r elative to the parent. Analysis of the latte r s train by Southe rn hybr idization indicated that the cassette was inde e d amplified several fold in MTX-re sistant derivatives. A sing l e strain, in which the cassette was inserted at the !lEA;], loc u.s , was used to examine in more detai 1 , the parameters affecting DFRl gene amplificat~ion in yeast . The mean B- gal activity in drug-resistant derivatives of this strain could be increased from 3 to 6 or 7 fold relative to the parent, by stepwise sel ection using increasing MTX concentrations. B-gal overproduction was found to be un stable in all primary and highly -resistant isolates examined. There was no indication, h owever, of a decrease i n growth r a t e in MTX-res i s tant cells which overproduced B - gal.

Transfection of newt blastema mesenchyme using the techniques of lipofection and direct gene transfer

The regenerating amphibian limb provides a useful system for studying genes involved in the establishment of positional information. While a number of candidate genes that may playa role in pattern formation have been identified, their function in vivo is unknown in this system. To better ascertain the role of these genes, it would be useful to be able to alter their normal patterns of expression in vivo and to assess the effects of this misexpression on limb pattern. In order to achieve this, a method of introducing a plasmid containing the eDNA of a gene of interest into a newt blastema (a growth zone of mesenchymal progenitor cells) is needed. Unfortunately, most commonly used transfection techniques cannot be used with newt blastema cells. In this study, I have used the techniques of lipofection and direct gene transfer to introduce plasmid DNA containing reporter genes into the cells of a regenerating newt limb. The technique of lipofection was most effective when the blastema cells were transfected in vitro. The optimal ratio for transfection was shown to be 1:3 DNA:Lipofectin (W/w) , and an increase in the amount of DNA present in the mixture (1:3 ratio maintained) resulted in a corresponding increase in gene expression. The technique of direct gene transfer was used to transfect newt blastema cells with and without prior complex formation with Lipofectin. Injection of plasmid DNA alone provided the most 3 promising results. It was possible to introduce plasmid DNA containing the reporter gene ~-galactosidase and achieve significant gene expression in cells associated with the injection site. In the future, it would be interesting to use this technique to inject plasmid DNA containing a gene which may have a role in pattern formation into specific areas of the newt blastema and to analyze the resulting limb pattern that emerges.

Remembering Lessons Learned: knowledge management techniques for building generational memory

A presentation made at the CAUT Librarians Conference in Ottawa, Ontario in October 2005.

Leisure connections : a case study to understand facilitation techniques with survivors of trauma

Leisure-based therapy is a potentially effective approach to supporting survivors of trauma in their healing. The purpose ofthis qualitative case study was to describe the recreation therapist's facilitation techniques of Leisure Connections, a unique leisurebased psycho-educational group for survivors of trauma, and explore how the facilitation was experienced by participants. Qualitative case study design, following the methods of Yin (1994) was used. One two week, three session Leisure Connections group was observed. Six participants completed the Group· Therapy Alliance Scale (pinsof & Catherall, 1986) and reflection cards. In-depth, semi-structured interviews were conducted with the recreation therapist and four participants. Six themes emerged describing group leader interventions, recreation therapist's actions, recreation therapist's preparation and reflections, group members' experience of a therapeutic alliance, group cohesion, and prior influences and assumptions. Therapeutic alliance and group cohesion were influenced by the recreation therapist's group leader interventions (drawing out, processing, protecting) and actions. The context of the group within a therapeutic community milieu was an important influence.

Strategies and Techniques for Teaching Children with Learning Disabilities: A Case Study of the Spring Reading Program

This case study explored strategies and techniques in order to assist individuals with learning disabilities in their academic achievement. Of particular focus was how a literacy-based program, titled The Spring Reading Program, utilizes effective tactics and approaches that result in academic growth. The Spring Reading Program, offered by the Learning Disabilities Association of Niagara Region (LDANR) and partnered with John McNamara from Brock University, supports children with reading disabilities academically. In addition, the program helps children increase their confidence and motivation towards literacy. I began this study by outlining the importance of reading followed by and exploration of what educators and researchers have demonstrated regarding effective literacy instruction for children with learning disabilities. I studied effective strategies and techniques in the Spring Reading Program by conducting a qualitative case study of the program. This case study subsequently presents in depth, 4 specific strategies: Hands-on activities, motivation, engagement, and one-on-one instruction. Each strategy demonstrates its effectiveness through literature and examples from the Spring Reading Program.

Changements techniques dirigés dans le commerce international: une comparaison d'approches pour les États-Unis.

Rapport de recherche