Teaching physiology online: successful use of case studies in a graduate course

To address the need for greater flexibility in access to higher education, an online graduate course in physiology using case studies was developed and offered in summer 2012. Topics in both animal and human physiology were organized as modules that contained a case study with questions, a prerecorded online lecture, and three research journal articles. We followed best practices for teaching and learning in distance education, including the preparation of materials before the course starting date, a discussion board for responding to pre- and postcase discussion questions, and prompt reply to student queries. For exams, students generated their own questions based on new cases and developed their own case study for the final project. Although only 20% of students had previously taken an online course, all students stated that they would recommend this course to others. Postcase assessment indicated that students found the cases interesting, informative, and presented at the appropriate level. Most students said that the online course took them more time but that they learned more content and used the primary literature more than in a traditional class. Our results indicate that a well-organized physiology course using a case study format is a very effective model for online learning. </jats:p

Range dynamics of small mammals along an elevational gradient over an 80-year interval

One expected response to observed global warming is an upslope shift of species elevational ranges. Here, we document changes in the elevational distributions of the small mammals within the Ruby Mountains in northeastern Nevada over an 80-year interval. We quantified range shifts by comparing distributional records from recent comprehensive field surveys (2006–2008) to earlier surveys (1927–1929) conducted at identical and nearby locations. Collector field notes from the historical surveys provided detailed trapping records and locality information, and museum specimens enabled confirmation of species' identifications. To ensure that observed shifts in range did not result from sampling bias, we employed a binomial likelihood model (introduced here) using likelihood ratios to calculate confidence intervals around observed range limits. Climate data indicate increases in both precipitation and summer maximum temperature between sampling periods. Increases in winter minimum temperatures were only evident at mid to high elevations. Consistent with predictions of change associated with climate warming, we document upslope range shifts for only two mesic-adapted species. In contrast, no xeric-adapted species expanded their ranges upslope. Rather, they showed either static distributions over time or downslope contraction or expansion. We attribute these unexpected findings to widespread land-use driven habitat change at lower elevations. Failure to account for land-use induced changes in both baseline assessments and in predicting shifts in species distributions may provide misleading objectives for conservation policies and management practices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78655/1/j.1365-2486.2009.02150.x.pd

Pharmacological and nutritional targeting of voltage-gated sodium channels in the treatment of cancers

International audienc

Post-translational modifications of voltage-gated sodium channels in chronic pain syndromes.

In the peripheral sensory nervous system the neuronal expression of voltage-gated sodium channels (Navs) is very important for the transmission of nociceptive information since they give rise to the upstroke of the action potential (AP). Navs are composed of nine different isoforms with distinct biophysical properties. Studying the mutations associated with the increase or absence of pain sensitivity in humans, as well as other expression studies, have highlighted Nav1.7, Nav1.8, and Nav1.9 as being the most important contributors to the control of nociceptive neuronal electrogenesis. Modulating their expression and/or function can impact the shape of the AP and consequently modify nociceptive transmission, a process that is observed in persistent pain conditions. Post-translational modification (PTM) of Navs is a well-known process that modifies their expression and function. In chronic pain syndromes, the release of inflammatory molecules into the direct environment of dorsal root ganglia (DRG) sensory neurons leads to an abnormal activation of enzymes that induce Navs PTM. The addition of small molecules, i.e., peptides, phosphoryl groups, ubiquitin moieties and/or carbohydrates, can modify the function of Navs in two different ways: via direct physical interference with Nav gating, or via the control of Nav trafficking. Both mechanisms have a profound impact on neuronal excitability. In this review we will discuss the role of Protein Kinase A, B, and C, Mitogen Activated Protein Kinases and Ca++/Calmodulin-dependent Kinase II in peripheral chronic pain syndromes. We will also discuss more recent findings that the ubiquitination of Nav1.7 by Nedd4-2 and the effect of methylglyoxal on Nav1.8 are also implicated in the development of experimental neuropathic pain. We will address the potential roles of other PTMs in chronic pain and highlight the need for further investigation of PTMs of Navs in order to develop new pharmacological tools to alleviate pain

Understanding glucose transport by the bacterial phosphoenolpyruvate. Glycose phosphotransferase system on the basis of kinetic measurements in vitro.

The kinetic parameters in vitro of the components of the phosphoenolpyruvate:glycose phosphotransferase system (PTS) in enteric bacteria were collected. To address the issue of whether the behavior in vivo of the PTS can be understood in terms of these enzyme kinetics, a detailed kinetic model was constructed. Each overall phosphotransfer reaction was separated into two elementary reactions, the first entailing association of the phosphoryl donor and acceptor into a complex and the second entailing dissociation of the complex into dephosphorylated donor and phosphorylated acceptor. Literature data on the K(m) values and association constants of PTS proteins for their substrates, as well as equilibrium and rate constants for the overall phosphotransfer reactions, were related to the rate constants of the elementary steps in a set of equations; the rate constants could be calculated by solving these equations simultaneously. No kinetic parameters were fitted. As calculated by the model, the kinetic parameter values in vitro could describe experimental results in vivo when varying each of the PTS protein concentrations individually while keeping the other protein concentrations constant. Using the same kinetic constants, but adjusting the protein concentrations in the model to those present in cell-free extracts, the model could reproduce experiments in vitro analyzing the dependence of the flux on the total PTS protein concentration. For modeling conditions in vivo it was crucial that the PTS protein concentrations be implemented at their high in vivo values. The model suggests a new interpretation of results hitherto not understood; in vivo, the major fraction of the PTS proteins may exist as complexes with other PTS proteins or boundary metabolites, whereas in vitro, the fraction of complexed proteins is much smaller

Evaluation of biochar for reduction of nitrogen compounds in stormwater remediation systems

Maresca, Julia AnneAs stormwater travels over impervious surfaces it collects a variety of contaminants, including nitrogenous compounds that can contribute to eutrophication if they reach water bodies. Engineering systems, such as bioretention facilities, can treat stormwater; however, these structures typically have inadequate removal of nitrogen compounds like ammonium (NH4+ ) and nitrate (NO3-). The objective of this study was to evaluate the potential for poultry litter (PL) or wood derived (WD) biochar to remove NH4+ and NO3- from artificial stormwater (ASW) and to evaluate any affects biochar may have on the microbial nitrogen cycle. Both PL and WD biochar removed more than 90% of the NH4+ from ASW solutions, while NO3- removal was negligible. WD biochar removed more NH4+ from ASW than PL biochar, and its NH4+ sorption capacity was not significantly affected by the presence of other cations in solution. Particle size of the biochar influenced adsorption. Smaller WD biochar had increased NH4+ adsorption, whereas smaller PL particle size increased NH4+ leaching into solution. In addition, PL biochar produced at 400??C had significantly higher leaching of NH4+ than PL biochar produced at 500??C. In column experiments, WD biochar slightly decreased the pH of the effluent, while PL biochar caused increase in effluent pH. Using the measured adsorption isotherms, the NH4+ sorption capacities of both PL and WD biochars were calculated for field conditions. At application rates of 2% by weight, calculated PL and WD biochar removal of NH4+ was quickly depleted. However, for WD biochar at 10% application, removal efficiencies of over 50% can be achieved for inflows over 200,000 L. This equates to effectiveness for multiple storm events. The microbial results of the experiments were inconclusive, needing a much larger scale of research to get a better representation of the soil communities. These results suggest that biochar can be a useful amendment to bioretention facilities for the removal of NH4+. However, source of the biochar and preparation techniques will influence sorption capacity and may induce different changes to the soil environment of the system.University of Delaware, Department of Civil EngineeringM.C.E