The mechanism by which potassium causes neurite retraction in lamprey descending neurons in cell culture

Abstract only availableSevere spinal cord injury (SCI) disrupts descending axons from reticulospinal (RS) neurons that project to the spinal cord. In most “higher” vertebrates, including humans, recovery is very minimal due to limited regeneration in the central nervous system, and paralysis is usually permanent below the injury site. In several lower vertebrates, including the lamprey, behavioral recovery is almost complete following SCI due to robust axonal regeneration. To study the cellular and molecular mechanisms that regulate axonal regeneration, neurons are often isolated in cell culture so that the factors that influence neurite outgrowth can be studied under controlled conditions. In our laboratory, we have developed a cell culture system in which neurite outgrowth of RS neurons can be studied (Hong et al., 2002; Ryan et al., 2004). Application of glutamate, an excitatory neurotransmitter, to the growth cones of RS neurons results in neurite retraction, presumably because of depolarization, calcium influx, and an increase in intracellular calcium. Intracellular calcium is thought to be one of the important regulators of the rate and direction of neurite outgrowth. Calcium influx could result from at least two different channels: chemically-gated channels (e.g. NMDA channels); or voltage-gated calcium channels. The purpose of the present study was to determine if calcium influx via voltage-gated calcium channels is sufficient to elicit neurite retraction. First, focal application of a 31 M potassium to growth cones of DiI-labeled RS neurons in culture to open voltage-gated calcium channels significantly reduced neurite growth rates, including neurite retraction, compared to pre-control periods. Second, 2 of Co++ or 300 M Cd++, which block calcium channels, abolished potassium-induced neurite retraction. In conclusion, the results suggest that calcium influx via voltage-gated calcium channels is sufficient to cause neurite retraction. Other experiments will determine if influx through voltage-gated channels is necessary for glutamate to elicit neurite outgrowth. Determination of the factors that regulate neurite outgrowth may provide information about the mechanism by which RS neurons regenerate their axons following spinal cord injury and restore locomotor function.Life Sciences Undergraduate Research Opportunity Progra

Evidence that glutamate induced neurite retraction of reticulospinal neurons is dependent on calcium influx

Abstract only availableLocomotor systems of vertebrates consist of a command system in the brain that activates central pattern generators in the spinal cord to initiate locomotor behavior. Reticulospinal (RS) neurons are the output neural elements of the command system. Following spinal cord injury, axons of RS neurons are severed and must regenerate to restore behavioral functions below the lesion. In higher vertebrates, such as birds and mammals, axonal regeneration is very limited, and spinal cord injury usually results in permanent paralysis below the lesion. In contrast, in the lamprey and a few other lower vertebrates, axonal regeneration is robust following spinal cord injury, and this results in virtually complete behavioral recovery. Therefore, identification of the mechanisms for axonal regeneration in lower vertebrates might provide information about the requirements for regenerating neurons in higher vertebrates. Examination of neurite outgrowth in culture is often used to identify the cellular and molecular mechanisms for axonal regeneration. In our laboratory, we have shown that application of glutamate, an excitatory neurotransmitter, to growth cones of RS neurons in culture causes neurite retraction, presumably by causing depolarization and calcium influx. Intracellular calcium levels are thought to be one of the important regulatory factors for neurite outgrowth. Glutamate might mediate calcium influx via at least two types of channels: chemically-gated channels (e.g. NMDA channels); or voltage-gated calcium channels. The purpose of the present study was to determine if calcium influx via voltage-gated channels is necessary for neurite retraction. The anatomical tracer DiI was applied to the spinal cord to pre-label RS neurons. Following transport, RS neurons were isolated and placed in cell culture. Glutamate was pressure ejected onto the growth cones of RS neurons in the presence of w-conotoxin MVIIC, which is a specific blocker for N and P voltage-gated calcium channels. Under these conditions, conotoxin reduced but did not block glutamate-induced neurite retraction. In conclusion, glutamate-induced neurite retraction of lamprey RS neurons probably is mediated by calcium influx via both chemically-gated and voltage-gated channels. Determination of the factors that regulate neurite outgrowth in culture may provide insights into the mechanisms for axonal regeneration and behavioral recovery following spinal cord injury in whole animals.Life Sciences Undergraduate Research Opportunity Progra

Principles of assembly reveal a periodic table of protein complexes

Structural insights into protein complexes have had a broad impact on our understanding of biological function and evolution. Here we seek a comprehensive understanding of the general principles underlying quaternary structure organisation in protein complexes. To do this, we first examine the fundamental steps by which protein complexes can assemble using experimental and structure-based characterisation of assembly pathways. Most assembly transitions can be classified into three basic types, which can then be used to exhaustively enumerate a large set of possible quaternary structure topologies. These topologies, which include the vast majority of observed protein complex structures, give rise to a natural organisation into a periodic table. Based upon this, we are then able to accurately predict the expected frequencies of quaternary structure topologies, including those not yet observed. Overall, these results have important implications for quaternary structure prediction, modelling and engineering.This work was supported by the Royal Society (S.E.A. and C.V.R.), the Human Frontier Science Program (J.A.M.), the Medical Research Council grant G1000819 (H.H. and C.V.R.) and the Lister Institute for Preventative Medicine (S.A.T.).This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aaa224

Developing teaching for mathematical resilience in further education

The construct ‘Mathematical Resilience’ [1] has been developed to describe a positive stance towards mathematics; resilient learners develop approaches to mathematical learning which help them to overcome the affective barriers and setbacks that can be part of learning mathematics for many people. A resilient stance towards mathematics can be engineered by a strategic and explicit focus on the culture of learning mathematics within both formal and informal learning environments. As part of that engineering, we have developed the notion of ‘Teaching for Mathematical Resilience’. The work described here is focused on developing teachers who know how explicitly to develop resilient learners of mathematics. Teachers for Mathematical Resilience develop a group culture of ‘can do’ mathematics which works to counter the prevalent culture of mathematics helplessness and mathematics anxiety in the general population when faced with mathematical ideas. This paper discusses the changes in awareness brought about by a one-day course designed to develop ‘teaching for mathematical resilience’. The course presentations ran between November 2015 and July 2016 and recruited participants who work as teachers of numeracy or mathematics in Further Education (FE) institutions in England – predominantly in the Midlands. Many of these teachers were being required to teach beyond their own level of mathematical confidence. The data shows that it is possible within a one day course to increase teachers’ awareness of negative past experiences as a possible cause of difficulty with mathematics; teachers become aware of how patterns of behaviour such as avoidance and disruption may have developed as safe-preservation habits and how mathematics anxiety can be transmitted from teacher to student in a vicious cycle. Teachers are supported to work through personal anxieties towards mathematics in a safe and collaborative environment and to develop elements of personal mathematical resilience and awareness of the affective domain. Thus we have sought to break the cycle of mathematics anxiety by educating teacher awareness. However, we have also found that many UK FE teachers request and would likely benefit from further courses

Principles of assembly reveal a periodic table of protein complexes.

Structural insights into protein complexes have had a broad impact on our understanding of biological function and evolution. In this work, we sought a comprehensive understanding of the general principles underlying quaternary structure organization in protein complexes. We first examined the fundamental steps by which protein complexes can assemble, using experimental and structure-based characterization of assembly pathways. Most assembly transitions can be classified into three basic types, which can then be used to exhaustively enumerate a large set of possible quaternary structure topologies. These topologies, which include the vast majority of observed protein complex structures, enable a natural organization of protein complexes into a periodic table. On the basis of this table, we can accurately predict the expected frequencies of quaternary structure topologies, including those not yet observed. These results have important implications for quaternary structure prediction, modeling, and engineering.This work was supported by the Royal Society (S.E.A. and C.V.R.), the Human Frontier Science Program (J.A.M.), the Medical Research Council grant G1000819 (H.H. and C.V.R.) and the Lister Institute for Preventative Medicine (S.A.T.).This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aaa224

Disability and the Dancing Body:A Symposium on Ownership, Identity and Difference in Dance

Acknowledgements We would like to thank Siobhan Davies Studios, which was aptly described by one of our participants as “a Cathedral for contemporary dance”, for hosting the symposium and assisting us on the day. We would also like to thank the staff at the Centre for Dance Research (C-Dare) at Coventry University for their support during the day. We would also, of course, like to thank the AHRC for its kind support of InVisible Difference.Peer reviewedPublisher PD

Breathing Easy: Lung Health and Associated Conditions in the Day Care Setting

Introduction: Air pollutants are associated with many health risks. Children in the day care environment are uniquely suscept-ible to lung damage, infection, systemic illness & pollutant triggered hypersensitivity reactions. The latest public report by the CDC reports Vermont’s (VT) asthma rate is the high-est in the country at 11.1%. This project compared VT’s day care regulations regarding specific environmental factors linked with health risks to regulations in six surrounding New England states. We sought to assess whether VT’s regulations adequately protect children in day carehttps://scholarworks.uvm.edu/comphp_gallery/1064/thumbnail.jp

Association between Pseudonocardia symbionts and Atta leaf-cutting ants suggested by improved isolation methods

Fungus-growing ants associate with multiple symbiotic microbes, including Actinobacteria for production of antibiotics.The best studied of these bacteria are within the genus Pseudonocardia, which in most fungus-growing ants are conspicuouslyvisible on the external cuticle of workers. However, given that fungus-growing ants in the genus Atta do not carry visibleActinobacteria on their cuticle, it is unclear if this genus engages in the symbiosis with Pseudonocardia. Here we explore whetherimproving culturing techniques can allow for successful isolation of Pseudonocardia from Atta cephalotes leaf-cutting ants. Weobtained Pseudonocardia from 9 of 11 isolation method/colony component combinations from all 5 colonies intensively sampled.The most efficient technique was bead-beating workers in phosphate buffer solution, then plating the suspension on carboxymethylcellulosemedium. Placing these strains in a fungus-growing ant-associated Pseudonocardia phylogeny revealed that while somestrains grouped with clades of Pseudonocardia associated with other genera of fungus-growing ants, a large portion of the isolatesfell into two novel phylogenetic clades previously not identified from this ant-microbe symbiosis. Our findings suggest thatPseudonocardia may be associated with Atta fungus-growing ants, potentially internalized, and that localizing the symbiont andexploring its role is necessary to shed further light on the association. [Int Microbiol 2013; 16(1):17-25

Morphometric analysis of ears in two families of pinnipeds

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 2001Pinniped (seal and sea lion) auditory systems operate in two acoustically distinct environments, air and water. Piniped species differ in how much time they typically spend in water. They therefore offer an exceptional opportunity to investigate aquatic versus terrestrial hearing mechanisms. The Otariidae (sea lions and fur seals) generally divide their time evenly between land and water and have several adaptations; e.g. external pinnae, related to this lifestyle. Phocidae (true seals) spend the majority of their time in water; they lack external pinnae and have well developed ear canal valves. Differences in hearing ranges and sensitivities have been reported recently for members of both of these familes (Kastak, D., Schusterman, RJ., 1998. Low frequency amphibious hearing in pinnipeds. J. Acoust. Soc. Am. 1303,2216- 2228.; Moore, P.W.B., Schusterman, RJ., 1987. Audiometric assessment of northern fur seals, Callorhinus ursinus. Mar. Mamm. Sci. 3,31-53.). In this project, the ear anatomy of three species of pinnipeds: an otariid, the California sea lion (Zalophus californianus), and two phocids, the northern elephant seal (Mirounga angustirostris) and the harbor seal (Phoca vitulina), was examined using computerized tomography (CT scans) and gross dissection. Thee-dimensional reconstructions of the heads and ears from CT data were used to determine interaural dimensions and ossicular chain morphometrics. Ossicular weights and densities were measured conventionally. Results strongly support a canalcentric system for pinniped sound reception and localization. Further, true seals show adaptations for aquatic high frequency specialization.I was supported by an NDSEG fellowship from ONR

Growth Mindset As an Approach for Improving Our Lives and Our Students\u27 Lives (August 2017)

This interactive presentation expands on the concept of growth mindset, the concept that growth and learning can come from failure, and discusses the impact that adopting a growth mindset can have on ourselves and our students. Concludes with some concrete suggestions for cultivating a growth mindset and embracing the power of yet