Dynamics of the SNARE-mediated synaptic vesicle fusion pore

SNARE-mediated membrane fusion is a key step in the process of neurotransmission. The release of neurotransmitters into the synapse as a result of vesicle fusion, particularly when triggered by an influx of Ca2+, serves as a primary means of signal propagation and communication in cognitive processes. Much work has been done to study these SNARE-mediated fusion events and the role auxiliary proteins play in modulating the overall process. However, our understanding of certain stages in the process is comparatively lacking, and our ability to study them has so far been curtailed by the relatively primitive state of current assays. This is particularly true for the opening and expansion of the fusion pore following hemifusion, necessary for the release of neurotransmitters from the vesicle into the synapse, which has gone largely unexamined despite its importance in understanding both the initial release and the life cycles of neurotransmitter-carrying vesicles. Despite prior difficulties, refinement of an in vitro single vesicle fusion assay to a sufficiently robust state has presented an opportunity to investigate. In this study, we develop a novel method for the study of fusion pore dynamics. Utilizing vesicles containing fluorescently labeled dextran with a vesicle-to-suspended bilayer fusion assay, we can observe the release the release of the dextran through the bilayer as the pore opens and expands beyond the hydrodynamic radius of the dextran. We further observe a halt in release as the pore shrinks beneath this radius, giving rise to multi-staged content release patterns common to many vesicle docking and fusion events in the presence of SNAREs alone. With this assay developed, we also perform preliminary studies into the roles of SNARE accessory proteins known to impact fusion. In particular, we observe the ability of α-synuclein to influence fusion pore dilation. While still in its early stages, we believe that our single vesicle content release assay can provide valuable insight into the roles of this and other proteins in modulating the dynamics of the fusion pore, and a greater understanding of the mechanisms of SNARE-mediated fusion as a whole

The Attentional Demands of Positive Reappraisal in a Dual Task Paradigm

Title from PDF of title page, viewed October 30, 2017Thesis advisor: Diane L. FilionVitaIncludes bibliographical references (pages 52-68)Thesis (M.A.)--Department of Psychology. University of Missouri--Kansas City, 2017Emotion regulation refers to the ability to modulate experienced and expressed emotions. A specific emotion regulation strategy, cognitive reappraisal, has received extensive attention in the literature, as the strategy is widely viewed as adaptive. Cognitive reappraisal effectively alters emotional experiences through a processes of reinterpreting a stimulus, situation or event before an emotion has been fully generated. By changing the meaning of a situation before an emotion fully develops, individuals have the potential to alter the extent to which they feel certain emotions. This strategy has been associated with a wide array of beneficial health and psychological outcomes, and is also used in treating different forms of psychopathology. Despite extensive evidence documenting the effectiveness of cognitive reappraisal, researchers have recently investigated potential negative outcomes associated with this strategy. Notably, researchers have demonstrated that cognitive reappraisal requires attention, and that the attentional demands required to use this strategy can impact performance in other areas. The present study sought to expand on these findings by examining an understudied type of cognitive reappraisal: positive cognitive reappraisal. Furthermore, the present study examined how the attentional demands associated with positive cognitive reappraisal change while the strategy is being implemented as opposed to after implementation. These goals were accomplished by having participants view unpleasant and neutral images, and positively reappraise a subset of unpleasant images while performing a concurrent reaction-time (RT) task, with stimuli for the RT task presented at pseudo-random SOAs during image presentation. Results revealed greater RT during the positive reappraisal condition compared to the negative image viewing condition, and this difference changed depending on when the RT stimuli were presented. A final exploratory question examined the extent to which self-reported worry might interfere with task performance, with results revealing no impact of worry on the pattern of RT observed across conditions. The results of this study demonstrated that engaging in positive cognitive reappraisal can interfere with the ability to respond to other environmental stimuli, suggesting the strategy requires attentional resources, and that the attentional resources required to use the strategy change during the regulatory process.Introduction -- Review of the literature -- Methodology -- Results -- Discussion -- Appendi

New Wilson’s Phalarope Nesting Record from the Central Platte River Valley, Mormon Island, Hall County, Nebraska

The southeastern portion of the Wilson’s Phalarope’s (Phalaropus tricolor) breeding range encompasses parts of Nebraska (Colwell and Jehl 1994), including the Sandhills and northern Panhandle (Silcock and Jorgensen 2018). Additionally, there have been a number of breeding records from southcentral and southeastern Nebraska within the Rainwater Basin ecoregion since the mid-1990s (Mollhoff 2016, Silcock and Jorgensen 2018). However, there is very little evidence of regular breeding activity in the nearby Central Platte River Valley (CPRV), which spans from Chapman west to Overton, Nebraska, and is considered a globally important area for waterbirds (Johnsgard and Brown 2013, Silcock and Jorgensen 2018). Sutton and Arcilla (2018) documented two juvenile Wilson’s Phalaropes with two adults on 28 June 2017, confirming successful breeding in the CPRV on Mormon Island, Hall County, Nebraska. However, Sutton and Arcilla (2018) did not document an active nest and therefore lack a detailed description of the nesting habitat used by Wilson’s Phalaropes in this unique ecoregion. On 6 June 2019 we found a Wilson’s Phalarope nest while walking between avian point count stations on Mormon Island, 4.7 km northwest of Doniphan and 14.4 km southwest of Grand Island, Nebraska, on land owned and managed for the benefit of migratory birds by the Crane Trust (https://cranetrust.org/). The landscape is managed with rotational grazing and prescribed fire to simulate natural disturbance regimes (Fuhlendorf et al. 2009). Mormon Island contains the largest contiguous tract of wet meadow remaining in the CPRV (Currier and Henszey 1996, Brei and Bishop 2008). Mormon Island consists of about 1075 hectares (ha) or 2,656 acres (ac) of primarily relict and restored wet meadow and lowland tallgrass prairie habitat, and exists within a complex of 2,425 ha (5,992 ac) of land protected for conservation purposes along a 13 km (~8 mi.) stretch of the Platte River. The nest was found when an adult male Wilson’s Phalarope flushed directly off the nest from the ground at a distance of approximately 3 meters (m) from approaching observers

Evaluation of Sealers and Waterproofers for Extending the Life Cycle of Concrete

Concrete pavements represent a large portion of the transportation infrastructure. While the vast majority of concrete pavements provide excellent long-term performance, a portion of these pavements have recently shown premature joint deterioration. Substantial interest has developed in understanding why premature joint deterioration is being observed in jointed portland cement concrete pavements (PCCP). While some have attributed this damage to insufficient air void systems, poor mixture design, or chemical reaction between the salt and the paste, it is the hypothesis of this work that a component of this damage can be attributed to fluid absorption at the joints and chemical reactions between the salt and chemistry of the matrix. This paper discusses the role of soy methyl ester - polystyrene blends (SME-PS) as a potential method to extend the service life of concrete pavements by limiting the ingress of salt solutions. The report discusses field application of the SME-PS blends for field investigation in Lafayette and Fishers. Low temperature-differential scanning calorimetry (LT-DSC) techniques identified noticeable differences between plain mortar samples and mortar treated with SME-PS. The report also discusses the development of a test to assess chloride solution ingress during temperature cycling. The aim of this work is to provide background on some aspects that can lead to joint deterioration and provide early documentation showing that sealers may help to reduce the impact of deicers on joint damage, thereby extending the life of the concrete pavement. It should be noted that these sites as well as others are still ongoing and should be monitored for long term performance. Application procedure for SME-PS should follow manufacturer’s recommendation

How neural representations of newly learnt faces change over time: Event-related brain potential evidence for overnight consolidation

Previous experiments have shown that a brief encounter with a previously unfamiliar person leads to the establishment of new facial representations, which can be activated by completely novel pictures of the newly learnt face. The present study examined how stable such novel neural representations are over time, and, specifically, how they become consolidated within the first 24 h after learning. Using event-related brain potentials (ERPs) in a between-participants design, we demonstrate that clear face familiarity effects in the occipito-temporal N250 are evident immediately after learning. These effects then undergo change, with a nearly complete absence of familiarity-related ERP differences 4 h after the initial encounter. Critically, 24 h after learning, the original familiarity effect re-emerges. These findings suggest that the neural correlates of novel face representations are not stable over time but change during the first day after learning. The resulting pattern of change is consistent with a process of consolidation

Qualitative Behavioural Assessment (QBA) as a welfare indicator for farmed Atlantic salmon (Salmo salar) in response to a stressful challenge

Animal welfare assessments have struggled to investigate the emotional states of animals while focusing solely on available empirical evidence. Qualitative Behavioural Assessment (QBA) may provide insights into an animal’s subjective experiences without compromising scientific rigor. Rather than assessing explicit, physical behaviours (i.e., what animals are doing, such as swimming or feeding), QBA describes and quantifies the overall expressive manner in which animals execute those behaviours (i.e., how relaxed or agitated they appear). While QBA has been successfully applied to scientific welfare assessments in a variety of species, its application within aquaculture remains largely unexplored. This study aimed to assess QBA’s effectiveness in capturing changes in the emotional behaviour of Atlantic salmon following exposure to a stressful challenge. Nine tanks of juvenile Atlantic salmon were video-recorded every morning for 15 min over a 7-day period, in the middle of which a stressful challenge (intrusive sampling) was conducted on the salmon. The resultant 1-min, 63 video clips were then semi-randomised to avoid predictability and treatment bias for QBA scorers. Twelve salmon-industry professionals generated a list of 16 qualitative descriptors (e.g., relaxed, agitated, stressed) after viewing unrelated video-recordings depicting varying expressive characteristics of salmon in different contexts. A different group of 5 observers, with varied experience of salmon farming, subsequently scored the 16 descriptors for each clip using a Visual Analogue Scale (VAS). Principal Components Analysis (correlation matrix, no rotation) was used to identify perceived patterns of expressive characteristics across the video-clips, which revealed 4 dimensions explaining 74.5% of the variation between clips. PC1, ranging from ‘relaxed/content/positive active’ to ‘unsettled/stressed/spooked/skittish’ explained the highest percentage of variation (37%). QBA scores for video-clips on PC1, PC2, and PC4 achieved good inter- and intra-observer reliability. Linear Mixed Effects Models, controlled for observer variation in PC1 scores, showed a significant difference between PC1 scores before and after sampling (p = 0.03), with salmon being perceived as more stressed afterwards. PC1 scores also correlated positively with darting behaviours (r = 0.42, p < 0.001). These results are the first to report QBA’s sensitivity to changes in expressive characteristics of salmon following a putatively stressful challenge, demonstrating QBA’s potential as a welfare indicator within aquaculture

Media and Repository Support Unit, University of Nebraska–Lincoln Libraries, Annual Report July 2018–June 2019

Increasingly, libraries are recognizing the importance of providing access to the research output of their universities. In a June 10, 2019, news release from the provosts of the Big Ten Academic Alliance (BTAA) titled “Sustaining Values and Scholarship” (available at https://tinyurl.com/yyu94aa9), they state, “The Big Ten Academic Alliance will continue its advocacy for a sustainable and open ecosystem of publication. . . . Collectively, our institutions’ more than 50,000 faculty are supported by over $10 billion (2017) in research funding, and our institutions have similarly invested significantly in our capacity to further our missions to advance knowledge. Together, we produce roughly 15% of the research publications in the United States.” This commitment to open information is reflected in the mission of the Media and Repository Support (MARS) unit of the UNL Libraries. We support the creation and preservation of the scholarly accomplishments of the University of Nebraska–Lincoln by providing an infrastructure for disseminating information and scholarship through Digital Commons (articles, reports, journals, books, and more), Luna (multimedia projects), and Rosetta (data) as well as by providing equipment that students and faculty can check out to capture video and digital images. Through our efforts, the intellectual contributions of UNL are provided, when possible, as open access to disseminate information to as wide a community as possible. We provide advice and consult with researchers and students on scholarly communication issues surrounding open education resources, copyright, options for rights management, publication, and preservation of information in coordination with other faculty and staff in the Libraries. We maintain close contact with staff from Archives & Special Collections to ensure that nondigital information is not overlooked in preservation plans. Faculty within the unit have developed close relationships with the UNL Office of Research, faculty across our campus, and colleagues at the other University of Nebraska campuses (through the University of Nebraska Consortium of Libraries, UNCL)