A Highly Sensitive Plant Hybrid Protein Assay System Based on the \u3cem\u3eSpm\u3c/em\u3e Promoter and TnpA Protein for Detection and Analysis of Transcription Activation Domains

TnpA is a multifunctional DNA binding protein encoded by the maize Suppressor-mutator (Spm) transposable element. TnpA is required for transposition and is a repressor of the unmethylated Spm promoter. While analyzing protein domains using a yeast GAL4-based hybrid system in transiently transformed tobacco cells, we found that TnpA represses the \u3e10-fold transcriptional activation observed when the GAL4 DNA-binding domain is used alone. By contrast, compared to the backgroundless TnpA DNA-binding domain alone, 33- to 45-fold activation of the Spm promoter was observed when the VP16 activation domain was fused to it. TnpA-binding sites, but no TATA box, were required for transcription activation. Among the TnpA deletion derivatives tested, those retaining the coding sequences for the DNA-binding and protein dimerization domains gave the highest level of transcription activation when fused with the VP16 activation domain. The TnpA gene and TnpA-binding sites in the short Spm promoter therefore provide a novel, highly sensitive single-hybrid system for identifying and studying plant transcription activation domains in plant cells

SOUND BITES: THE IMPACT OF BOAT NOISE ON FRESHWATER FISH

Noise pollution is rapidly becoming more prevalent on a global scale, yet it is one of the least studied anthropogenic disturbances. Sound has low attenuation in water where it travels five times further than it does in air. Such effects, coupled with the wide spatial and temporal distribution of anthropogenic noise, makes noise pollution a major concern for aquatic species that may lack refuge from this modern-day stressor. This thesis explores how boat noise impacts freshwater fish behaviour and is divided between a lab and field experiment. The lab experiment investigated how fathead minnow and brook char’s anti-predator responses to a looming stimulus was influenced by play-back tracks. Tracks were either recordings of boat noise from different distances (100, 250, 500 and 1000 m) or ambient lake recordings for our control. The field experiment looked at how yellow perch’s oxygen consumption, or stress level, was influenced by exposure to boat noise at different distances away from the running motor (same distances as lab experiment) compared to ambient lake noises. The results from our field experiment showed generally that the closer the boat was to the yellow perch, the more stressed the individual was. Furthermore, the majority of the fish exposed to boat noise at any distance used significantly more DO (dissolved oxygen) compared to individuals that were only exposed to ambient lake noises. In contrast, the lab experiment showed no evidence that boat noise influenced fathead minnow or brook char anti-predator responses; however, use of pre-recorded tracks in the laboratory may minimize effects. Future research needs to continue to understand how to use play-back tracks in a lab setting to create more ecologically relevant conditions. This research adds to the limited literature on how anthropogenic noise is influencing freshwater species

Concerted Formation of Macromolecular \u3cem\u3eSuppressor-mutator\u3c/em\u3e Transposition Complexes

Transposition of the maize Suppressor-mutator (Spm) transposon requires two element-encoded proteins, TnpA and TnpD. Although there are multiple TnpA binding sites near each element end, binding of TnpA to DNA is not cooperative, and the binding affinity is not markedly affected by the number of binding sites per DNA fragment. However, intermolecular complexes form cooperatively between DNA fragments with three or more TnpA binding sites. TnpD, itself not a sequence-specific DNA-binding protein, binds to TnpA and stabilizes the TnpA-DNA complex. The high redundancy of TnpA binding sites at both element ends and the protein-protein interactions between DNA-bound TnpA complexes and between these and TnpD imply a concerted transition of the element from a linear to a protein crosslinked transposition complex within a very narrow protein concentration range

The Recombinant DNA Controversy: A Contemporary Cautionary Tale

A discussion of the scientific and political aspects of recombinant DNA research

Agricultural Biotechnology-An Opportunity to Feed a World of Ten Billion

The latest United Nations population projections predict that the human population will expand from roughly 7.5 billion to between 8.3 and 10.9 billion by mid-century. This presents an acute need to increase agricultural productivity quickly and to do so without unduly damaging the many other kinds of organisms that share our planet. The advances of genetic engineering and genetic modification hold the promise of making it possible for us to grow more food on the same amount of land using less water, energy, and chemicals: critically important objectives if we are to live sustainably within planetary constraints. At the same time, these advances have evoked an almost unprecedented level of societal controversy quite specifically in the realm of food production, resulting in the proliferation of regulatory and legal issues that threaten to block their use in achieving a more sustainable existence for humanity on planet Earth. If modem science is to contribute to the agricultural productivity increases required in coming decades as the climate warms and the human population continues to grow, it is imperative to get beyond the cultural and political biases against molecular crop modification, acknowledge the safety record of GM crops, and ease the regulatory barriers to their development and deployment

Circles of support and accountability (CoSA): a review of the development of CoSA and its international implementation

Circles of Support and Accountability (CoSA) was initially developed in Canada as a community-based program designed to assist in the community reintegration of individuals who are deemed a high or very high risk of sexual recidivism. This article outlines the historical foundations and frameworks of the CoSA model and examines the recruitment and training of CoSA volunteers. It reviews the impact that CoSA has on recidivism, as well as the psychosocial implications of the model on the former offenders participating in CoSA (the ‘Core Members’), volunteers, and the community at large. International implementation of CoSA is addressed by a review of project initiatives undertaken around the world. This article concludes by addressing the future directions of CoSA, both within Canada and internationally