Effects of Dredge Material Placement on Macroinvertebrate Communities: Phase 1

ID: 8809; issued October 1, 1998INHS Technical Report prepared for Rock Island District, US Army Corps of Engineer

Human Erythrocyte Glucose Transporter (GLUT1) Structure, Function, and Regulation: A Dissertation

The structure-function relationship explains how the human erythrocyte glucose transport protein (GLUT1) catalyzes sugar transport across the plasma membrane. This work investigates the glucose transport mechanism, the structural arrangement and dynamics of GLUT1 membrane-spanning α-helices, the molecular basis for glucose transport regulation by ATP, and how cysteine accessibility contributes to GLUT1 structure. A rapid kinetics approach was applied to examine the conformational changes GLUT1 undergoes during the transport cycle. To transition from a global to molecular focus, a novel mass spectrometry technique was developed to resolve GLUT1 sequence that is associated either with membrane embedded GLUT1 subdomains or with water exposed domains. By studying accessibility changes of specific amino acids to covalent modification by a Sulfo-NHS-LC-Biotin probe, specific protein regions associated with glucose transport modulation by ATP were identified. Finally, mass spectrometry was applied to examine cysteine residue accessibility under native and reducing conditions. This thesis presents data supporting the isolation of an intermediate, occluded GLUT1 conformational state that temporally bridges import and export configurations during glucose translocation. Our results confirm that amphipathic α-helices line the translocation pathway and promote interactions with the aqueous environment and substrate. In addition, we show that GLUT1 is conformationally dynamic, undergoes reorganization in the cytoplasmic region in response to ATP modulation, and that GLUT1 contains differentially exposed cysteine residues that affect its folding

Gene Expression and Profiling of Human Islet Cell Subtypes: A Master’s Thesis

Background: The endocrine pancreas contains multiple cell types co-localized into clusters called the Islets of Langerhans. The predominant cell types include alpha and beta cells, which produce glucagon and insulin, respectively. The regulated release of these hormones maintains whole body glucose homeostasis, essential for normal metabolism and to prevent diabetes and complications from the disease. Given the heterogeneous nature of islet composition and absence of unique surface markers, many previous studies have focused on the whole islet. Sorting islet cells by intracellular hormone expression overcomes this limitation and provides pure populations of individual islet cell subsets, specifically alpha and beta cells. This technique provides the framework for characterizing human islet composition and will work towards identifying the genetic changes alpha and beta cells undergo during development, growth, and proliferation. Methods: Human islets obtained from cadaveric donors are dissociated into a single cell suspension, fixed, permeabilized, and labeled with antibodies specific to glucagon, insulin, and somatostatin. Individual alpha, beta, and delta cell populations are simultaneously isolated using fluorescence activated cell sorting. Candidate gene expression and microRNA profiles have been obtained for alpha and beta cell populations using a quantitative nuclease protection assay. Thus far, RNA has been extracted from whole islets and beta cells and subjected to next generation sequencing analysis. Results: The ratio of beta to alpha cells significantly increases with donor age and trends higher in female donors; BMI does not appear to significantly alter the ratio. Further, we have begun to investigate the unique gene expression profiles of alpha and beta cells versus whole islets, and have characterized the microRNA profiles of the two cell subsets. Conclusions: By establishing methods to profile multiple characteristics of alpha and beta cells, we hope to determine how gene, miRNA, and protein expression patterns change under environmental conditions that lead to beta cell failure or promote beta cell development, growth, and proliferation

Diversity of Flower-visiting Bees and their Pollen Loads on a Wildflower Seed Farm in Montana

During a two-year survey on a wildflower seed farm in southcentral Montana, we collected ∼50 species of bees from 18 genera in sweep samples on cultivated wildflowers and weeds. The two cultivated plant species most intensively sampled attracted different assemblages of bee visitors. Slender white prairie clover (Dalea candida) attracted 27 species, 94% of visitors being Apis mellifera (73%), Lasioglossum spp., Colletes phaceliae, and Bombus spp. Prairie coneflower (Ratibida columnifera) attracted 20 species, the majority being Halictus rubicundus and three Melissodes species; only 3% of visitors to this plant were A. mellifera, despite the fact that the coneflower field was closer to an apiary than were the prairie clover fields. Other apparently non-random plant-bee associations included A. mellifera onOnobrychis viciaefolia, Bombus spp. on Astragalus cicer, and Halictus ligatus and aMelissodes sp. on Symphyotrichum chilensis. Analysis of pollen loads suggests high flower constancy for A. mellifera, Bombus spp., and many of the native solitary bee species foraging on cultivated plants. The low numbers of honey bees on certain plants suggest that native, non-managed bees of such genera as Bombus, Melissodes, Halictus, and Lasioglossum may be critical for plant species for which honey bees show relatively low preference (especially when highly-preferred species such as D. candida are abundant)

When Protests go Virtual: How Organizing Social Protest in Virtual Worlds Changes the Nature of Organizing

In this paper, we introduce a case study of social protest that has occurred in the virtual world Second Life. This case is a labor strike that occurred against IBM by Italian employees and a large European labor union. We begin with identifying the four key elements in the protest organizing process: Identifying Supporters, Organizing and Establishing Hierarchy, Getting the Word Out, and Building Solidarity/Establishing Social Networks. Next, we briefly examine how non-virtual technologies have changed the protest organizing process. Finally, we present our case data and illustrate how moving a protest to a fully virtual environment changes the organizing process. We conclude by asserting that three aspects fundamentally change protest organizing: entertainment, costs, and culture

Gene Expression and Profiling of Human Islet Cell Subtypes

The endocrine pancreas contains multiple cell types co-localized into clusters called the islets of Langerhans. The predominant cell types include alpha and beta cells, which produce glucagon and insulin, respectively. The regulated release of these hormones maintains whole body glucose homeostasis, essential to prevent complications from diabetes (e.g. blindness, kidney failure, and cardiovascular disease). In type 1 diabetes, an autoimmune reaction destroys the beta cells and patients must monitor their blood sugar levels and inject insulin in order to maintain euglycemia. In type 2 diabetes, the beta cells fail to produce sufficient insulin to overcome the individual’s decreased insulin sensitivity. Most studies to date have focused on whole islets, which are very heterogeneous. Recent focus has shifted to studying the individual islet cell subsets (i.e. alpha, beta, delta, PP, and other cell types). Unlike immunological cells, surface molecule reagents do not yet exist to specifically distinguish beta from alpha cells. We have successfully isolated pure populations of insulin producing beta cells and glucagon producing alpha cells by using intracellular hormone staining and fluorescence activated cell sorting. We present data that describe the ratio of beta cells to alpha cells across gender, age, and BMI. Further, we have characterized the miRNA profiles of alpha and beta cells and have begun to investigate the unique gene expression patterns of the two cell types. By developing the ability to profile multiple characteristics of alpha and beta cells, we hope to determine how gene, miRNA, and protein profiles change under environmental conditions that lead to beta cell failure, and others that may promote beta cell health or stimulate beta cell growth and proliferation

Associations Between Adolescent Sport and Exercise Participation and Device-Assessed Physical Activity in Adulthood: Evidence From the 1970 British Cohort Study

BACKGROUND: Adolescence is a critical period filled with life changes. Early implementation of effective health promotion strategies could help alleviate the morbidity and mortality associated with inactivity. This study investigated whether adolescent participation in exercise and sport is associated with device-assessed physical activity (PA) levels in midlife. METHODS: A total of 2984 participants (41.2% male) from the 1970 British Cohort Study were included. Participants were surveyed at age 16 years on 5 indicators of exercise and sport participation. Total daily PA and moderate to vigorous PA (MVPA) at age 46 years were measured using a thigh-worn accelerometer, worn for 7 days. Associations between each adolescent exercise or sport indicator and adulthood total daily PA and MVPA were examined using linear regressions, adjusting for sex, wear time, body mass index, smoking, disability, malaise, alcohol consumption, social class, education, and self-rated health. RESULTS: In fully adjusted models, adolescents who reported exercising "much more" than others (8.6 min/d; 95% confidence interval, -0.1 to 17.1), who played sports at the park/playground more than once a week (8.5 [3.0-14.0] min/d), and who exercised on the most recent Saturday (3.8 [0.7-6.9] min/d) had higher adult total PA levels than those who reported the lowest activity levels. There was no evidence of an association between greater sport and exercise participation at age 16 y and MVPA at age 46 y. There was no association between sports at school and either measure of adult PA. CONCLUSION: Active adolescents, particularly those who engaged in out-of-school exercise, had higher total daily PA levels, but not MVPA levels, in midlife. This highlights the potential of early PA interventions to improve PA levels in adulthood

Dose-response association between step count and cardiovascular disease risk markers in middle aged adults

Several step-based daily targets have been widely circulated, but there is a lack of empirical population-based evidence to support such guidance. We examined dose-response associations between step count and classical CVD risk markers (glycated haemoglobin, high density lipoprotein cholesterol, triglycerides, C-reactive protein) in 4,665 adults (aged 46 yr; 51.4% female) in a cross-sectional study. Step counts were measured from a thigh mounted accelerometer (activPAL) worn over 7 days. The shape of the dose response curve for most risk markers was 'L-shaped', with linear risk reduction up to around 10,000 steps a day. Controlling for stepping intensity did not materially alter our results

Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium

Background and Aims: Physical inactivity, sedentary behaviour (SB), and inadequate sleep are key behavioural risk factors of cardiometabolic diseases. Each behaviour is mainly considered in isolation, despite clear behavioural and biological interdependencies. The aim of this study was to investigate associations of five-part movement compositions with adiposity and cardiometabolic biomarkers. Methods: Cross-sectional data from six studies (n = 15 253 participants; five countries) from the Prospective Physical Activity, Sitting and Sleep consortium were analysed. Device-measured time spent in sleep, SB, standing, light-intensity physical activity (LIPA), and moderate-vigorous physical activity (MVPA) made up the composition. Outcomes included body mass index (BMI), waist circumference, HDL cholesterol, total:HDL cholesterol ratio, triglycerides, and glycated haemoglobin (HbA1c). Compositional linear regression examined associations between compositions and outcomes, including modelling time reallocation between behaviours. Results: The average daily composition of the sample (age: 53.7 ± 9.7 years; 54.7% female) was 7.7 h sleeping, 10.4 h sedentary, 3.1 h standing, 1.5 h LIPA, and 1.3 h MVPA. A greater MVPA proportion and smaller SB proportion were associated with better outcomes. Reallocating time from SB, standing, LIPA, or sleep into MVPA resulted in better scores across all outcomes. For example, replacing 30 min of SB, sleep, standing, or LIPA with MVPA was associated with −0.63 (95% confidence interval −0.48, −0.79), −0.43 (−0.25, −0.59), −0.40 (−0.25, −0.56), and −0.15 (0.05, −0.34) kg/m2 lower BMI, respectively. Greater relative standing time was beneficial, whereas sleep had a detrimental association when replacing LIPA/MVPA and positive association when replacing SB. The minimal displacement of any behaviour into MVPA for improved cardiometabolic health ranged from 3.8 (HbA1c) to 12.7 (triglycerides) min/day. Conclusions: Compositional data analyses revealed a distinct hierarchy of behaviours. Moderate-vigorous physical activity demonstrated the strongest, most time-efficient protective associations with cardiometabolic outcomes. Theoretical benefits from reallocating SB into sleep, standing, or LIPA required substantial changes in daily activity.British Heart Foundation Special Grant (SP/F/20/150002)National Health and Medical Research Council (Australia) Investigator (APP1194510) and Ideas (APP1180812) GrantsUnrestricted 2018-20 grant by PAL Technologies (Glasgow, UK)FORTE, Swedish Research Council for Health, Working Life and Welfare (2021-01561)National Health and Medical Research Council Investigator Grant (APP1194510)National Health and Medical Research Council Principal Research Fellowship (APP1121844)British Heart FoundationHorizon 2020 Framework Programme of the European UnionNational Institute for Health Research University College London Hospitals Biomedical Research CentreUK Medical Research CouncilNational Institute for Health ResearchWellcome Trust and works in a unit that receives support from the UK Medical Research Counci