bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shape change throughout the body of the tongue during drinking in the striped skunk (Mephitis mephitis)
Authors: Olson Rachel A. , Montuelle Stéphane J. , Curtis Hannah E. , Williams Susan H. 
Published: June 2021

In mammals, the tongue plays a central role in many oral behaviors, but it is particularly essential for feeding and drinking. During feeding, the tongue is used for ingestion, manipulation and positioning of food within the oral cavity, and swallowing. When mammals drink, they do so by lapping, licking, or sucking, and the tongue is vital to uptake and transport of fluid into and through the oral cavity and oropharynx. All of these behaviors are performed with only a partial reliance on a bony support system; instead the tongue engages in complex movements as a muscular hydrostat – where selective contraction of intrinsic and extrinsic muscle fibers produce movements and deformations of the tongue. The tongue's anatomical complexity and its location inside the oral cavity make it particularly difficult to visualize and study the movements that contribute to these and other oral behaviors. The objective of this study is to test the ability of marker‐based XROMM (X‐ray reconstruction of moving morphology) to track shape changes throughout the body of the tongue. The striped skunk (Mephitis mephitis), a mammalian omnivore belonging to the order Carnivora, was used as a model for rhythmic lapping while drinking a barium liquid. Data was collected using XROMM with markers implanted in the bones of the skull as well as in the body of the tongue. Tongue markers were used to calculate length changes throughout the body of the tongue. Timing and movement parameters are also registered to the gape cycle derived from the rigid body motions derived from skeletal markers. Based on an analysis of 150 cycles, during rhythmic drinking, the middle and posterior tongue underwent the most variation in length change, while the anterior tongue underwent the least amount of variation in length. In contrast, the posterior tongue underwent the least amount of variation in tongue width, as compared to the anterior and middle tongue. Maximum overall tongue length occurred 2.74±29.3 msec before maximum gape, whereas minimal overall tongue length occurred 20.24±7.38 msec before minimum gape. Based on these preliminary results, this method shows promise for producing quantitative data for studying tongue deformations within the oral cavity. Future studies incorporating spatial parameters of the tongue to the rest of the feeding apparatus across mammals will further our understanding of how the tongue functions during feeding and drinking behaviors.Support or Funding InformationNational Science Foundation Grant DBI‐0922988, National Science Foundation Grant IOS‐1456810This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Synthesis and Biochemical Use of N‐Hydroxyl‐N‐(5‐aminopentyl)succinamic acid (HSC) by the Enzyme FslA
Authors: Nguyen James , Hoffmann Katherine 
Published: June 2021

Siderophores are small, high affinity iron chelators used by bacteria for resource gathering. Non‐Ribosomal Peptide Synthetases manufacture siderophores using a novel and under‐described chemistry: they create peptide bonds outside of a ribosome, in the process consuming ATP and a high‐energy adenylate intermediate. Beyond basic science, NIS synthetase have a novel fold and chemistry making it a good target for antibiotic design. Despite their interesting function, there are only nine relevant articles on PubMed database about NIS Synthetases. DesD is a model enzyme for this novel family, an enzyme from Streptomyces coelicolor that makes the siderophore desferrioxamine E. The Hoffmann Lab is pursuing a full biochemical characterization of DesD, which will require the appropriate techniques as well as access to the substrates in a pure, soluble form.DesD is an iterative enzyme, meaning it catalyzes multiple bonds on the same substrate. Specifically, DesD catalyzes all of these events: the serial linking of three molecules of N‐Hydroxyl‐N‐(5‐aminopentyl)succinamic acid (HSC) into a linear trimer called desferrioxamine G, and then a macrocylization event linking the ends. The initial binding of two HSC molecules is a very different binding site occupancy than the binding of the linear trimer for the cyclization bond, and any biochemical characterization should quantify this binding and any differences in kinetics. Desferrioxamine G can be commercially bought to study binding of DesD. HSC however, cannot be bought, only synthesized. This project is concerned with the synthesis of HSC and then the use of it in binding and kinetic studies. While the synthesis has been published in the literature, we have made adjustments to improve yield. Additionally, we are optimizing purification via HPLC. This substrate will be used in thermodynamic binding studies via isothermal titration calorimetry and compared to current binding isotherms of the larger substrate. With the study of large substrate and small substrate thermodynamics and kinetics will contribute both to the understanding of NIS synthetases and of iterative enzymes more broadly.TSupport or Funding InformationThis work was supported by a grant from the National Science Foundation (MCB ‐ 1716986) to K.M.H, and by California Lutheran University.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intact Cell Assay to Measure Agonist‐ and GRK2‐Dependent Phosphorylation of the α2A‐Adrenergic Receptor
Authors: Farina Zachary , Hebert Aaron‐Michael , Weldin Erica , Varney Matthew , Sterne‐Marr Rachel 
Published: June 2021

The α2A‐adrenergic receptor (α2A‐AR) is a G protein‐coupled receptor (GPCR) that is activated by the catecholamines epinephrine and norepinephrine. Its physiological roles include inhibition of insulin secretion from pancreatic beta cells, cardiovascular vasoconstriction, and the inhibition of lipolysis in adipocytes (among other functions). GPCRs are often phosphorylated in an agonist‐dependent fashion and thereby desensitized by GPCR kinases (GRKs). GRK2 phosphorylates the α2A‐AR in vitro and when co‐transfected with the receptor in monkey kidney (COS‐7) cells. GRK2 phosphorylation occurs at four consecutive serine residues in the third intracellular loop of the α2A‐AR (residues 296–299). We recently mapped sites on GRK2 that are necessary for phosphorylation of the β2‐adrenergic receptor and interaction with the α2A‐adrenergic receptor in intact cells. In order to test GRK2 mediated α2A‐AR phosphorylation, we generated an antibody that detects α2A‐AR phosphorylation at serines 296–299. We are developing an intact cell assay to assess residues on both GRK2 and the receptor that are important for α2A‐AR phosphorylation. This will give us a greater understanding of the regulation of this physiologically important receptor.Support or Funding InformationThis work was funded by the National Science Foundation MCB0744739 to Rachel Sterne‐Marr and the Siena College Center for Undergraduate Research and Creative Activity.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Investigating gibberellin phytohormone biosynthesis by plant‐associated bacteria
Authors: Peters Reuben J. 
Published: June 2021

Gibberellins (GAs) are structurally complex diterpenoids that serve as important hormones in plants, with crucial roles in growth and development, but also in modulating defense. Beyond their endogenous production by vascular plants, GAs also are produced by plant‐associated microbes, both fungi and bacteria. We have recently elucidated the biosynthetic pathway by which bacteria produce GA, revealing convergent evolution, yet striking similarities in the underlying (bio)chemical transformations. We are currently engaged in mechanistic studies of the enzymes catalyzing the relevant complex reactions, including structure‐function analyses. In addition, we also are investigating the physiological function of such bacterial phytohormone production and have found two surprisingly distinct roles, which seem to depend on the nature of the plant‐bacteria relationship. In phytopathogens, production of bioactive GA seems to serve to increase virulence. By contrast, symbiotic rhizobia produce only the penultimate precursor, and seem to have co‐evolved with their leguminous host, which catalyze the final step to produce a bioactive GA that then assists symbiosis. Our most recent results will be discussed.Support or Funding InformationThis work was supported, in part, by grants from the USDA (NIFA‐AFRI‐2014‐67013‐21720) and NSF (CHE‐1609917).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Understanding How the Protein Environment Accelerates Cofactor‐Free O2 Activation in Antibiotic Biosynthesis Monooxygenases (ABMs)
Authors: Ellis Emerald , Machovina Melodie M. , DuBois Jennifer L. 
Published: June 2021

Molecular oxygen is a nontoxic, naturally abundant, thermodynamically powerful oxidant. Most enzyme‐catalyzed oxidation and oxygenation processes using O2 depend on small, tightly bound metal‐containing or organic cofactors, such as heme or flavin, to activate O2 and thereby accelerate its reaction with organic substrates. Antibiotic Biosynthesis Monooxygenases (ABMs) are a large family of small proteins with the unusual ability to catalyze direct reactions between their substrates and O2 without any cofactors. Prior studies of a representative ABM, Nogalamycin MonoOxygenase (NMO), suggested that its reaction proceeds by rate limiting electron transfer to form a superoxide/substrate radical pair. By comparing the rate and thermodynamic parameters for the catalyzed and uncatalyzed reactions, we sought to determine how the protein environment of NMO helps to catalyze the direct reaction between its substrate and O2. Marcus Theory relates the activation energy (ΔG‡, the difference in energy between the substrate and transition state) to the thermodynamic driving force (ΔG°, the difference in energy between substrate and product) and the reorganization energy (λ0, the energy required to reorganize all atomic nuclei in the reaction sphere without electron transfer): ΔG‡ =(ΔG° + λ0)2/4λ0. Prior work showed that for the flavin‐containing enzyme glucose oxidase, the reorganization energy was responsible for most of the difference in ΔG‡ between the enzymatic and uncatalyzed electron transfers that occur between flavin and O2. A single conserved positive charge was essential for lowering ΔG‡ and therefore accelerating the reaction. We hypothesized that λ0 might likewise be the major contributor to ΔΔG‡ (catalyzed versus uncatalyzed) in NMO, though these enzymes lack conserved positive charges. Here, we tested that hypothesis by measuring ΔG° (via spectroelectrochemical titration of the midpoint potentials) and ΔG‡ (Arrhenius plots) for uncatalyzed and NMO‐catalyzed oxygenation reactions, as well as for reactions catalyzed by two key NMO active site mutants. Our results suggest an unconventional means for accelerating reactions between O2 and certain classes of substrate that depends solely on a properly tuned protein environment.Support or Funding InformationNational Science Foundation, MCB1715176This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
IL‐6 and Bile Acids are Skin‐Derived Factors that Regulate Whole‐Body Metabolism in SCD1 Deficient Mice
Authors: Dumas Sabrina N. , Guo Chang‐an , Ntambi James M. 
Published: June 2021

Stearoyl‐CoA desaturase 1 (SCD1) is a lipogenic enzyme that catalyzes the rate limiting step in monounsaturated fatty acid synthesis by inserting a double bond at the delta‐9 position of long‐chain fatty acids. Specifically, SCD1 converts stearate (18:0) to oleate (18:1n9) and palmitate (16:0) to palmitoleate (16:1n7). Global deletion of SCD1 in mice (GKO) provides complete resistance to both high‐carbohydrate and high‐fat diet‐induced obesity. Furthermore, GKO mice also demonstrate improved insulin sensitivity and glucose clearance. Surprisingly, skin‐specific deletion of SCD1 also provides protection from high‐fat diet‐induced obesity and similar metabolic improvements to GKO mice. Histological analysis of SKO skin demonstrates dermal deviations that include 1) an increased number of hair follicles despite progressive hair‐loss, 2) increased macrophage infiltration and 3) differentially expressed IL‐6 that is localized around hair follicles. Co‐localization of macrophage and IL‐6 markers reveal that IL‐6 is not produced by macrophages but instead is produced by cells of the hair follicles. In plasma, IL‐6 protein levels are 25‐fold increased relative to controls, and downstream IL‐6‐mediated metabolic effects are increased at least 5‐fold in distal tissues such as white adipose tissue and liver. Another skin‐derived factor in SKO mice is bile acids, in that, genetic analysis of bile acid synthesis genes in the skin and liver of SKO mice show unexpected and divergent expression. Cyp7a1 the rate‐limiting bile acid synthesis gene is unchanged in SKO liver, but the extrahepatic equivalent Cyp7b1 is significantly increased in skin. In plasma, bile acid composition is not only increased but is also significantly skewed towards increased levels of tauro‐β‐muricholic acid which is indicative of increased extrahepatic bile acid synthesis in mice. Furthermore, the bile acid pool is also more hydrophilic which is a phenotype that is protective against the development of diseases of the metabolic syndrome. Together, changes in both IL‐6 and bile acid composition in SKO mice strongly suggest that skin metabolism is an important component of whole‐body metabolism, and this opens another avenue for the treatment of metabolic diseases.Support or Funding InformationSabrina Dumas was supported by USDA Hatch W2005This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Modifications in MUC2 and OCLN Expression in Human Alveolar Adenocarcinoma Epithelial Cells Following E‐Cigarette Chemical Exposure
Authors: Wright Alexis , Mitchum Jessica , Daft Joseph G. 
Published: June 2021

Electronic cigarettes (e‐cigarettes) have entered the market promoting a healthy and clean alternative to conventional tobacco cigarettes. Aggressive marketing has led to an increase in usage of e‐cigarettes among adults and adolescents. Despite the promotion of e‐cigarettes as an alternative for tobacco users, the chemical composition of these two products is very similar. Two of the predominant chemicals found in e‐cigarettes are formalin and methylbenzaldehyde, of which, formalin is also found in tobacco cigarettes. We hypothesize that exposure of the alveolar adenocarcinoma (A549) cells to these common e‐cigarette chemicals will alter the lung epithelial barrier as measured by occludin (OCLN) and mucin‐2 (MUC2) expression.Mucin‐2 is a protein that secretes a protective mucus membrane and occludin is a tight junction protein, both contributing to a functional and protective lung epithelial barrier. Overexpression of MUC2 can lead to hypersecretion of mucus, while under expression of OCLN can cause an increase in epithelial permeability, representing a disruption of this barrier. A549 cells will be treated with physiological concentrations of formalin and methylbenzaldehyde to mimic e‐cigarette exposure. We will show that exposure to formalin and methylbenzaldehyde alters MUC2 and OCLN, indicating a disruption of the lung epithelial barrier. These results represent the negative health effects associated with e‐cigarette use, which contradicts the current advertisements marketing e‐cigarettes as a safe product.Support or Funding InformationNational Science Foundation Grant# 1458212This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A transient dopamine signal represents the value of avoidance in negative reinforcement
Authors: Roberts Jonte , Pultorak Katherine , Busch Brandon , Oleson Erik 
Published: June 2021

The mesolimbic dopamine (DA) system has traditionally been examined under a reward based context. While accumulating evidence supports that DA release events represent the value of predicted rewards, there is little known about its role in avoidance. To investigate dopamine's role in the valuation of signaled operant avoidance, we developed an economics‐based shock avoidance task in which rats were given the opportunity to avoid (signaled by the presentation of a cue light) electrical foot‐shock across epochs wherein the unit price (response requirement over mA shock) to avoid or escape increases. After developing this task, we first used fast‐scan cyclic voltammetry (FSCV) to measure DA release events in vivo as the animals performed across a range of prices. We observed that the concentration of DA decreased with price, though both DA and avoidance were initially suppressed at session onset. To establish a causal role, we then used optogenetics to augment DA release at either the presentation of the cue signal or upon successful avoidance of the foot‐shock. Increasing release at the cue made avoidance more sensitive to price; whereas increasing release at successful avoidance made it less sensitive to price. We conclude that this is likely because the neural representation of the value to avoid is greater than predicted at successful avoidance, and worse than expected at the cue on trials in which foot‐shock is administered. We will next assess the role of the rostromedial tegmental nucleus (RMTg), a neural structure known to cause prediction errors, in the valuation of avoidance.Support or Funding InformationFunding for the project was provided by NSF grant IOS‐1557755, NIH grant R03DA038734, Boettcher Young Investigator Award and NARSAD Young Investigator Award to EBO and an institutional UROP to KJP.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Identification of residues in human melatonin type 2 receptor involved in signaling selectivity or general signal transmission using natural variants
Authors: Plouffe Bianca , Karamitri Angeliki , Flock Tilman , Gallion Jonathan M. , Bonnefond Amélie , Guillaume Jean‐Luc , Le Gouill Christian , Froguel Philippe , Lichtarge Olivier , Deupi Xavier , Jockers Ralf , Bouvier Michel 
Published: June 2021

Melatonin is a neurohormone secreted by the pineal gland mainly regulating circadian rhythm and binding to 2 receptors: MT1 and MT2. A recent genome‐wide association studies revealed 40 non‐synonymous polymorphisms of MT2. All these variants are normally expressed at cell surface and 4 of them show loss of melatonin binding. Given that no crystal structure is available yet for MT2 and that variants are well distributed along MT2, we took advantage of these natural variants to delineate structural features controlling MT2 functionality. By monitoring β‐arrestin 2 recruitment, ERK phosphorylation, inhibition of cAMP production, Gαi1 and Gαz activation, we generated 40 signaling signatures and similar profiles were grouped together using non‐negative matrix factorization (NMF). A total of 8 different types of signatures (clusters) were obtained. Each cluster has unique signaling features and is distinctly spatially localized along MT2. While residues important for general signal transmission are located in transmembrane regions, the residues responsible for signal selectivity are almost exclusively localized in intracellular domains. Using computational homology modeling (PDB ID: 4Zwj and 3sn6), we proposed molecular mechanisms underlying general signal transmission but also Gα/β‐arrestin and Gαz/Gαi1 selectivities. Altogether, our findings represent a proof of principle that natural variants of a given receptor can be exploited and used as a platform to learn more about its structural properties.Support or Funding InformationThis work was supported by a grant from FRQS to MB, from FRM and ANR to RJ and from NIH, NSF and DARPA to OL. Postdoctoral fellowships from CIHR and from Diabetes Canada to BP, from FRM to AK and from ETH Zurich to TF also funded this work.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Site‐Specific Dueteration Decreases Cytrochrome P450 Production of 12‐Hydroxy‐Nevirapine through the Kinetic Isotope Effect
Authors: Heck Carley J. S. , Seneviratne Herana Kamal , Bumpus Namandjé N. 
Published: June 2021

The non‐nucleoside reverse transcriptase inhibitor nevirapine (NVP), classified as an essential medication by the World Health Organization, has been shown to cause life‐threatening hepatotoxicity and skin rash in patients. The 12‐hydroxyNVP (12‐OHNVP) metabolite of NVP has been implicated in these toxicities and here we aimed to gain a detailed understanding of utility of introducing deuteriums at the 12‐position of NVP as an approach to decreasing the formation of this metabolite. To do so, an ultra‐high performance liquid chromatograph tandem high‐resolution mass spectrometry assay was developed and employed to detect 12‐OHNVP formation following incubation of NVP with human liver microsomes and individual cDNA‐expressed enzymes. Through this work, we found that formation of 12‐OHNVP was most abundant following incubation with cytochrome P450 (P450; CYP) 2C19 although each of the P450s tested, with the exception of CYP3A5, catalyzed the formation of 12‐OHNVP to some extent. In line with this, formation of 12‐OHNVP by human liver microsomes was not abrogated in the presence of any established small molecule inhibitors of P450 activity including ketoconazole (CYP3A inhibitor). In order to test whether the deuterium kinetic isotope effect could be employed to control 12‐OHNVP production by all P450s we investigated the impact of 12th position deuteration of NVP on the formation of this metabolite. Human liver microsomes were incubated with 10 μM NVP or 10 μM 12‐d3NVP for 30 minute and the production of the 12‐OHNVP was measured. The abundance of 12‐OHNVP was 6.8‐fold lower when human liver microsomes were incubated with 12‐d3NVP, as compared to undeuterated NVP incubations. Of note, no difference in the formation of other P450‐dependent metabolites of NVP was observed. In order to test the impact of deuterium kinetic isotope effects on the metabolism of NVP in a whole cell system, we measured metabolite levels in the medium of primary mouse hepatocytes treated with 10 μM NVP and 12‐d3NVP for 24 hours. A 4.7‐fold decrease was observed in 12‐OHNVP production in the medium of cells treated with deuterated NVP as compared to undeuterated NVP. As with the human liver microsome experiments, no significant difference was observed in the production of other P450‐dependent metabolites between treatments. These results demonstrate that dueteration at the 12th position can markedly decrease cytochrome P450 production of 12‐OHNVP through the kinetic isotope effect. The impact of this controlled metabolism on NVP toxicity will be a subject of further research. This work was funded by NSF GRFP DGE‐1232825 awarded to CJSH and NIH R01 GM103853.Support or Funding InformationThis work was funded by NSF GRFP DGE‐1232825 awarded to CJSH and NIH R01 GM103853.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.