Identification and characterisation of novel genes involved in neural cell fate specification/asymmetric cell division during the development of the Drosophila embryonic nervous system The generation of cellular diversity is a fundamental process in the development of multicellular organisms. The understanding of asymmetric cell division has come mainly from studies involving the early embryonic development of the nematode C. elegans and the CNS development of the fruit fly Drosophila melanogaster. Although a number of proteins which localise to the apical cortex of Drosophila neuroblasts have been identified which are required to facilitate their asymmetric divisions, many questions still remain as to how these proteins interact with the cell cortex and control the downstream processes of mitotic spindle orientation as well as the asymmetric localisation and segregation of cell fate determinants. Other proteins so far unidentified are likely to be involved in these processes. I propose to conduct a mutagenesis screen using the Drosophila melanogaster neuroblasts as a model to identify novel genes involved in asymmetric cell division of the early embryonic CNS. The main problem associated with identifying novel proteins using this model system is the high levels of maternally contributed protein that could allow normal divisions in an apparent mutant background. I intend to use the FLP/FRT system in conjunction with the dominant female sterile insert P[ovoD] to create germline clones within the female germline which will remove the maternally contributed protein. Embryos generated from the germline clones will be assessed to see what effects they have on asymmetric cell divisions as judged by immunohistochemical analysis using a variety of molecular markers for the developing embryonic CNS. The novel genes identified in the screen will be characterised with respect to their role in localising the previously identified proteins involved in asymmetric cell division, as well as on coordinating mitotic spindle orientation. Genetic epistasis studies will be conducted to determine where they lie within the hierarchy of genes already known to be involved in the process. In addition, molecular and biochemical studies will be performed to determine the nature of the gene products and their likely mechanisms of action. The screen is likely to produce a number of novel candidate genes involved in asymmetric cell division, which will extend our current understanding of this field. The novel genes identified from this screen will likely help elucidate presently unanswered questions within this field. Specifically, addressing how do these proteins localise to specific regions on the cell cortex, the mechanism involved in the localisation and maintainance at this site, and also identifying the links between the apically localised protein complex and the mitotic spindle.

Around half a million people die from pesticide poisoning each year in Asia and the Western Pacific. Most deaths are due to organophosphorus (OP) pesticides; other frequently lethal pesticides are paraquat and phosphide rodenticides. Both primary prevention and improved medical management could rapidly reduce deaths. However, there is little activity on either front. Pesticide regulation is sporadic and usually based on animal data. Current protocols for management of pesticide poisoning are based on little evidence and are difficult to deliver in the resource-poor settings in which most poisonings occur. The few systematic reviews conducted suggest there is no good quality human evidence that any antidote other than atropine is of benefit. Building on a collaboration currently funded by the Wellcome Trust, we propose to establish an Australian/Sir Lankan research collaboration to evaluate methods to reduce deaths from deliberate self-poisoning with pesticides. Tackling the problem on four complementary fronts (research into pathophysiology, antidotes, preventive strategies and improved delivery of evidence based clinical care) we believe we can achieve a 50% reduction in deaths. We will systematically review the evidence for the effectiveness of treatments for pesticide poisoning using Cochrane collaboration methods and test strategies to incorporate available evidence into clinical practice. We will collect data on the relative human toxicity of different pesticides, to guide a strategy to prevent poisoning through pesticide regulation. The most toxic pesticides will be restricted in selected districts. If deaths are reduced, then the restriction will be applied across the country. The neurotoxic effects of OP (Intermediate Syndrome and delayed neuropathy) cause many deaths through respiratory failure. We will conduct serial clinical and neurophysiological examinations to determine if these can be predicted, treated or prevented. A simple algorithm to predict prognosis in paraquat poisoning is needed to identify patients suitable for inclusion in antidote studies - we will determine if changes in creatinine can be used. We will do five phase II studies on new antidotes for pesticides: sodium bicarbonate for chlorphenoxy herbicides; antioxidant therapy for paraquat; sodium bicarbonate, clonidine and diazepam for OP. The effectiveness of the most promising antidote will be tested in a large Phase III study. By including prospective health-economic assessments on new and standard treatments, the costs and benefits of this will be apparent. All strategies are chosen such that they may be adopted by similar programs in other countries of the region.