A Proximity-Dependent Biotin Labeling Based Screen For Protein Kinase A Anchoring Proteins Within Focal Adhesion Complexes

Protein kinase A (PKA) regulates a diverse array of cellular activities including metabolism, differentiation, actomyosin contractility, and migration. The multifunctionality of this ubiquitous enzyme is achieved, in part, through subcellular targeting mediated by the A Kinase Anchoring Proteins (AKAP) family of proteins. AKAPs serve as scaffolding proteins that localize PKA to various cellular compartments and bring together specific targets and modulators of PKA activity. The importance of spatially restricted PKA signaling is particularly apparent in the context of cell motility. It has been observed that both anchoring through AKAPs and the subsequent localized activation of PKA at the leading edge of migrating cells are required for directed migration in multiple cell types. Despite the significant body of evidence linking PKA to the regulation of cellular adhesion, contractility, and migration, the mechanisms governing the spatiotemporal control of PKA signaling during these activities is not fully understood. Focal adhesion complexes, which connect the actin cytoskeleton to the extracellular matrix and are thus intimately involved in the adhesive and contractile state of the cell, are attractive potential sites of PKA signaling. We have evidence indicating that PKA is active within these complexes, and that this activity impacts focal adhesion dynamics. To address the question of how PKA may be recruited to adhesive complexes, we have developed a targeted screen to identify PKA interacting proteins within adhesive and cytoskeletal structures. This method utilizes proximity-dependent biotin labeling in combination with a focal adhesion purification preparation and downstream proteomic analysis. The results of this screen will be used to identify candidate AKAPs and will serve as the foundation for future inquiry into the complex role of PKA in the regulation of cell migration

Phylogenetic Distance Does Not Predict Competitive Ability in Green Algal Communities

An assumption often made by ecologists and phylogeneticists—that closely related species possess similar traits and ecology—can be extended into the hypothesis that closely related species compete more heavily than distant relatives due to shared ecology. The intuition that related species occupy similar niches and thus compete intensely for resources, one outcome of which is competitive exclusion and local reduction of biodiversity, was formally introduced by Darwin in 1859. The past decade has seen a steady rise in tests of Darwin’s “competition-relatedness hypothesis” that experimentally manipulate relatedness, or evolutionary history represented by species in a community, and then measure interaction strengths. Despite the initial enthusiasm for using evolutionary history to predict ecology, different competition studies have arrived at different conclusions regarding whether there is a positive, negative, or no relationship between species’ evolutionary relatedness and the strength of competitive interactions between them. Furthermore, these studies have primarily measured competition for pairs of species rather than the overall competition a species experiences within a multi-species community where more complex (e.g., indirect) interactions might be expected to take place. In order to test whether the competition-relatedness hypothesis holds in communities with a species richness more representative of that found in nature, a mesocosm study was performed using communities of eight species of freshwater green algae. Species relatedness was quantified as the phylogenetic distance between species using a comprehensive multi-gene molecular phylogeny of 59 North American green algae. Three metrics of competition strength—sensitivity to competition (reduction in intrinsic growth rate when grown from low density with competitors versus when grown in monoculture), relative yield, and competitive release (proportional change in biomass of a focal species grown with one competitor missing versus when grown with all competitors)—were not predicted by the relatedness of a species to its community. The finding that species’ relatedness to their resident community was unrelated to the strength of competition they experienced concurs with previous findings from studies of interaction strength as a function of relatedness between pairs of species. This finding suggests that the results of prior studies refuting the competition-relatedness hypothesis can be extended to larger communities in which more complex ecological interactions occur.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/108172/1/opus_naughton.pd

Carbonyl-Twisted 6-Acyl-2-dialkylaminonaphthalenes as Solvent Acidity Sensors

Derivatives of 2-propionyl-6-dimethylaminonaphthalene (PRODAN) with twisted carbonyl groups were investigated as highly responsive sensors of H-bond donating ability. The PRODAN derivative bearing a pivaloyl group (4) was prepared. The torsion angle between the carbonyl and naphthalene is 26° in the crystal. It shows solvatochromism that is similar to five other PRODAN derivatives (1–3, 5, 6). Twisted-carbonyl derivatives 3, 4, and 6 show strong fluorescence quenching in protic solvents. The order of magnitude of the quenching is linearly related to the H-bond donating ability of the solvent (SA) but not to other solvent properties. Binary mixtures of protic solvents show specific interaction effects with respect to quenching and solvatochromism. Aggregation in water is an issue with the pivaloyl derivatives

Plasma free fatty acids metabolic profile with LC-MS and appetite-related hormones in South Asian and White European men in relation to adiposity, physical activity and cardiorespiratory fitness : a cross-sectional study

South Asians have a greater cardiovascular disease (CVD) and type 2 diabetes (T2D) risk than white Europeans, but the mechanisms are poorly understood. This study examined ethnic differences in free fatty acids (FFAs) metabolic profile (assessed using liquid chromatography-mass spectrometry), appetite-related hormones and traditional CVD and T2D risk markers in blood samples collected from 16 South Asian and 16 white European men and explored associations with body composition, objectively-measured physical activity and cardiorespiratory fitness. South Asians exhibited higher concentrations of five FFAs (laurate, myristate, palmitate, linolenic, linoleate; p ≤ 0.040), lower acylated ghrelin (ES = 1.00, p = 0.008) and higher leptin (ES = 1.11, p = 0.004) than white Europeans; total peptide YY was similar between groups (p = 0.381). South Asians exhibited elevated fasting insulin, C-reactive protein, interleukin-6, triacylglycerol and ratio of total cholesterol to high-density lipoprotein cholesterol (HDL-C) and lower fasting HDL-C (all ES ≥ 0.74, p ≤ 0.053). Controlling for body fat percentage (assessed using air displacement plethysmography) attenuated these differences. Despite similar habitual moderate-to-vigorous physical activity (ES = 0.18, p = 0.675), V ˙ O2max was lower in South Asians (ES = 1.36, p = 0.001). Circulating FFAs in South Asians were positively correlated with body fat percentage (r2 = 0.92), body mass (r2 = 0.86) and AUC glucose (r2 = 0.89) whereas in white Europeans FFAs were negatively correlated with total step counts (r2 = 0.96). In conclusion, South Asians exhibited a different FFA profile, lower ghrelin, higher leptin, impaired CVD and T2D risk markers and lower cardiorespiratory fitness than white Europeans

Potential of PRODAN derivatives as chemosensors of the microacidity of cyclodextrin host-guest complexes

Fluorescent chemosensors facilitate the characterization of materials and biological systems. Cyclodextrin (CD), a conical sugar oligomer with a hydrophobic interior and exterior hydroxyl groups, is water-soluble and presents a binding site for fluorescent probes such as PRODAN (6-propionyl-2-dimethylaminonaphthalene). The quenching of PRODAN-based probes occurs as their environment is better able to donate hydrogen bonds, an effect which is enhanced by a twisted conformation of the carbonyl group of the probe. After titrating six structurally distinct probes with beta-CD, emission spectra were analyzed for binding constants, maximum increase of fluorescence quantum yield, and effective solvent acidity of the beta-CD environment. Probes with twisted conformations gave an approximately twenty-fold increase in maximum quantum yield and may bind more strongly to cyclodextrin. While the ideal sensor for microacidity should have increased response to changing environment, the increase should not come at the expense of the range of detectable solvent acidities

Overcoming Legal and Institutional Barriers to the Implementation of Innovative Environmental Technologies

This paper examines the possible reasons that stormwater management system operators (typically municipalities) have generally been reluctant to adopt RTC technology. Our interdisciplinary team of law faculty, engineering faculty, and graduate students from both disciplines studied dozens of examples involving RTC implementation in the United States and abroad. We also examined the literature detailing institutional barriers to RTC innovation. Finally, we reviewed numerous legal decisions related to municipal liability for stormwater management (or mismanagement). From this foundation, we distilled several institutional and legal barriers that prevent municipalities from embracing this particular type of innovation. The paper suggests a variety of strategies to combat these institutional and legal barriers to smooth the transition to RTC systems

Physical activity, and risk factors for Diabetes and Cardiovascular disease in South Asian and European men

Aims: To examine risk factors for type 2 diabetes and cardiovascular disease in South Asian (SA) and white European (WE) men and their relationship with physical activity (PA) levels, cardiorespiratory fitness and food intake. Methods: Sixteen SA and sixteen WE men matched by age (30 ± 8 vs. 36 ± 8 years) and BMI (25.7 ± 5.2 vs. 25.2 ± 3.3) completed a cross-sectional observational study involving body composition assessment by air displacement plethysmography, analysis of metabolic markers, inflammatory factors, appetite hormones and maximal aerobic capacity (VO2max). PA levels and food intake were assessed using triaxial accelerometry, the European Prospective Investigation into Cancer (EPIC) Norfolk PA questionnaire, and three-day food diary. Results: SA had a higher body fat percentage (BF%) (26.4 ± 9.0 vs. 19.5 ± 7.0 %), C-reactive protein, insulin area under the curve, triglyceride and leptin (P < 0.05), whereas acylated ghrelin (AG), insulin sensitivity index, high density lipoprotein cholesterol and VO2max were significantly lower (P < 0.05) compared with WE. No group differences were noted for other biomarkers, self-reported PA or food intake. SA were more sedentary (P = 0.030) while WE spent more time in light physical activities using accelerometry (P = 0.023). Several markers were significantly (P < 0.05) associated with VO2max, notably AG (r=0.472) and BF% (r=-0.718) and sedentary PA levels with leptin (r=0.430) and TAG (r=0.428). Conclusion: SA demonstrated increased cardiometabolic risk compared with WE. Furthermore, low cardiorespiratory fitness and low PA levels were associated with several cardiometabolic risk markers

Development of energetic and enzymatic limitations on microbial carbon cycling in soils

Soil organic carbon (SOC) constitutes an important reservoir in the global carbon cycle that is vulnerable to transformation and loss from land use and climate change. Anoxic conditions protect SOC from microbial degradation through limiting the energetics of respiration and inhibiting extracellular oxidative enzymes. Given growing evidence of prevalent anaerobic microsites in upland soils, we designed an experiment testing the development of dissolved organic carbon (DOC) signatures of energetic and enzymatic limitations on microbial carbon utilization across simulated soil aggregates or peds. Reactors comprised a soil column “aggregate” underlying an advective “macropore” channel. Soils received downward diffusive inputs of aerated porewater media with added nitrate, sulfate, or no amendment—where native ferrihydrite served as dominant anaerobic terminal electron acceptor (TEA). After 40 days, added nitrate resulted in highest bulk respiration and DOC production while sulfate did not differ from the control. Nominal oxidation state of carbon (NOSC) was higher (more favorable) with added TEAs at soil surfaces and decreased with depth, while NOSC in the non-amended soil remained lower and constant with depth. DOC generally increased with depth, which along with decreasing NOSC values indicates joint electron-donor and acceptor control over respiration energetics. Of all organic compound classes, only the relative abundance of phenolics increased between 0 and 0.5 cm depth, which aligns with the oxic-anoxic transition and suggests oxidative enzyme inhibition. Our results suggest that oxygen limitation within upland soil aggregates may preserve SOC via both energetic and enzymatic C protection mechanisms, which are vulnerable upon exposure to oxygen. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Office of Under Secretary for Science12 month embargo; first published online 30 March 2021This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]