Mode of action of FMRFamide-like peptide on drosophila body wall muscle conractions

Neuropeptides are the largest group of signalling chemicals that can convey the information from the brain to the cells of all tissues. DPKQDFMRFamide, a member of one of the largest families of neuropeptides, FMRFamide-like peptides, has modulatory effects on nerve-evoked contractions of Drosophila body wall muscles (Hewes et aI.,1998) which are at least in part mediated by the ability of the peptide to enhance neurotransmitter release from the presynaptic terminal (Hewes et aI., 1998, Dunn & Mercier., 2005). However, DPKQDFMRFamide is also able to act directly on Drosophila body wall muscles by inducing contractions which require the influx of extracellular Ca 2+ (Clark et aI., 2008). The present study was aimed at identifying which proteins, including the membrane-bound receptor and second messenger molecules, are involved in mechanisms mediating this myotropic effect of the peptide. DPKQDFMRFamide induced contractions were reduced by 70% and 90%, respectively, in larvae in which FMRFamide G-protein coupled receptor gene (CG2114) was silenced either ubiquitously or specifically in muscle tissue, when compared to the response of the control larvae in which the expression of the same gene was not manipulated. Using an enzyme immunoassay (EIA) method, it was determined that at concentrations of 1 ~M- 0.01 ~M, the peptide failed to increase cAMP and cGMP levels in Drosophila body wall muscles. In addition, the physiological effect of DPKQDFMRFamide at a threshold dose was not potentiated by 3-lsobutyl-1-methylxanthine, a phosphodiesterase inhibitor, nor was the response to 1 ~M peptide blocked or reduced by inhibitors of cAMP-dependent or cGMP-dependent protein kinases. The response to DPKQDFMRFamide was not affected in the mutants of the phosholipase C-~ (PLC~) gene (norpA larvae) or IP3 receptor mutants, which suggested that the PLC-IP3 pathway is not involved in mediat ing the peptide's effects. Alatransgenic flies lacking activity of calcium/calmodul in-dependent protein kinase (CamKII showed an increase in muscle tonus following the application of 1 JlM DPKQDFMRFamide similar to the control larvae. Heat shock treatment potentiated the response to DPKQDFMRFamide in both ala1 and control flies by approximately 150 and 100 % from a non heat-shocked larvae, respectively. Furthermore, a CaMKII inhibitor, KN-93, did not affect the ability of peptide to increase muscle tonus. Thus, al though DPKQDFMRFamide acts through a G-protein coupled FMRFamide receptor, it does not appear to act via cAMP, cGMP, IP3, PLC or CaMKl1. The mechanism through which the FMRFamide receptor acts remains to be determined.

Mode of action of a Drosophila FMRFamide in inducing muscle contraction

Drosophila melanogaster is a model system for examining the mechanisms of action of neuropeptides. DPKQDFMRFamide was previously shown to induce contractions in Drosophila body wall muscle fibres in a Ca(2+)-dependent manner. The present study examined the possible involvement of a G-protein-coupled receptor and second messengers in mediating this myotropic effect after removal of the central nervous system. DPKQDFMRFamide-induced contractions were reduced by 70% and 90%, respectively, in larvae with reduced expression of the Drosophila Fmrf receptor (FR) either ubiquitously or specifically in muscle tissue, compared with the response in control larvae in which expression was not manipulated. No such effect occurred in larvae with reduced expression of this gene only in neurons. The myogenic effects of DPKQDFMRFamide do not appear to be mediated through either of the two Drosophila myosuppressin receptors (DmsR-1 and DmsR-2). DPKQDFMRFamide-induced contractions were not reduced in Ala1 transgenic flies lacking activity of calcium/calmodulin-dependent protein kinase (CamKII), and were not affected by the CaMKII inhibitor KN-93. Peptide-induced contractions in the mutants of the phospholipase C-β (PLCβ) gene (norpA larvae) and in IP3 receptor mutants were similar to contractions elicited in control larvae. The peptide failed to increase cAMP and cGMP levels in Drosophila body wall muscles. Peptide-induced contractions were not potentiated by 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, and were not antagonized by inhibitors of cAMP-dependent or cGMP-dependent protein kinases. Additionally, exogenous application of arachidonic acid failed to induce myogenic contractions. Thus, DPKQDFMRFamide induces contractions via a G-protein coupled FMRFamide receptor in muscle cells but does not appear to act via cAMP, cGMP, IP3, PLC, CaMKII or arachidonic acid.

Making it "click": collaborative perceptions of creative practice in art education /

Making it "Click": Collaborative Perceptions ofCreative Practice in Art Education examined the teaching practice of 6 art educators who conducted their work through the Niagara Falls Art Gallery's (NFAG) in-schools and Children's Museum programmes. These community resources service the elementary levels of participatory Public, Catholic and French schools in the Niagara Peninsula. The goal of this research was to find ways in which these teachers could explore their creative potential as art educators. The "click," a term introduced by participants indicating the coming together of all positive factors towards creativity, became the central theme behind this study. Research revealed that the effective creative process was not merely a singular phase, but rather a series of 4 processes: 1 , gathering knowledge; 2, intuitive and experiential; 3, the informal presentation of information in which creativity as a process was explored; and 4, formal presentation that took the analysis of information to a deeper, holistic level. To examine the ways in which experience and knowledge could be shared and brought together through a collaborative process, this study employed data collection that used literature research, interviews, focus group discussions, and personal journal entries. Follow-up discussions that assessed the effectiveness of action research, took place VA months after the initial meetings. It is hoped that this study might assist in creative educational practices, for myself as a member of the NFAG teaching team, for colleagues in the art programmes, art educators, and other teachers in the broader disciplines of education.

An exploratory study of nurses' perceptions of their action learning experience /

Each year, the College of Nurses of Ontario (CNO) requires all registered nurses and registered practical nurses in Ontario to complete a Reflective Practice learning activity. In doing so, nurses are expected to perform a self- assessment, identify a practice problem or issue, create and implement a personal learning plan, and evaluate the learning and outcomes accomplished. The process and components of CNO's Reflective Practice program are very similar to an Action Learning activity. The purpose of this qualitative research was to explore the perceptions of 1 1 nurses who completed at least 1 Action Learning activity. Data analysis of their comments provided insight into their perceptions of the Action Learning experience, perceptions of the negative and positive characteristics of various activities within the Action Learning process, and perceptions of barriers or challenges within this experience. The author concluded that participants perceived their Action Learning activities to be a positive experience because the process focused on practice problems and issues, enhanced thinking about practice problems, and achieved practice-relevant outcomes. However, the results indicated that self-directed learning and journal writing were difficult activities for some participants, and some experienced negative emotional responses during reflection. The research concluded that barriers to implementation of Action Learning include a lack of understanding of the process and a perceived lack of support from employers.