bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Temperature and Nutrition on Growth Efficiency of the South American Locust (Schistocerca cancellata) During the Sixth Instar
Authors: Elliott Deanna B. , Youngblood Jacob P. , Angilletta Michael J. , Cease Arianne J. 
Published: April 2020

Throughout history, locust swarms have caused ecological and economic destruction in agricultural communities. Today, there are 20 species responsible for plagues on every continent excluding North America and Antarctica. In recent years, the South American species Schistocerca cancellata has wrought such devastation that Argentina and Bolivia were forced to declare states of emergency. Temperature and nutritional content of crops are known to be important variables in where a swarm will occur, but how these phenomena interact has not been studied. This experiment was intended to determine which temperature and dietary composition cause the highest growth rate in S. cancellata, based on the assumption that swarms may very well occur in places where the locusts are most likely to maximize their fitness. To this end, 180 locusts were separated into treatments composed of all combinations of three temperatures and three diets. Each treatment lasted the length of each animal’s 6th instar. Temperatures were held at 25°C, 35°C, and 42.5°C, and diets with protein‐to‐carbohydrate ratios of 0P:42C, 14P:28C, and 35P:7C were fed. Once completed, waste was collected and weighed, and then compared to the mass of diet consumed in order to determine how much mass was retained. Additionally, the caloric content of the diets and waste was measured to calculate energy efficiency between treatments. The hottest treatments tended to result in the highest, fastest growth rate, while the cold treatments grew less and took significantly longer to reach adulthood. The diet highest in protein showed the most weight gain, while the on with no protein had very few survivors. The results of this study may help to predict where and when locust swarms will occur, based on weather and crop content in South America, and allow for precautions, such as chemical control measures, to take place in the probable affected areas.Support or Funding InformationNSF LEAP Scholars Program
Sex Differences in Offensive and Defensive Investment in Crayfish Claws
Authors: Vargas Cindy , Graham Zackary A. , Palaoro Alexandre , Angilletta Michael 
Published: April 2020

Many animals possess weapons that have evolved to inflict damage to opponents during territorial encounters. Although the offensive capabilities of these weapons are important determinants of contest success, the defensive capabilities of the weapons are also important. However, current theory only accounts for investment into offensive performance, and not defensive endurance. To help better understand these dynamics, we investigated claw strength, cuticle thickness, and injury rates in male and female virile crayfish (Faxonius virilis). To measure the offensive capacity of a claw, we collected the max pinch of 3–5 pinches of each claw using a force transducer. To measure the defensive capacity of the claw, we dissected and measured the cuticle thickness of the carapace and seven sections of the claw: merus, dorsal manus, ventral manus, dorsal dactyl, ventral dactyl, dorsal pollex, and the ventral pollex. Injury rate was determined by visual inspection of the claw. Both male and female virile crayfish engage in aggression over access to both food and shelter. Thus, we expected each sex to invest similarly into the offensive and defensive abilities of their weapons. Interestingly, we found that despite males having proportionally larger claws, the average strength for a given size of the claw was similar between the sexes. Furthermore, we did not detect any sex differences in defensive ability as measured by cuticle thickness and injury rates. Overall, we demonstrated that both male and female virile crayfish invest similarly into the offensive and defensive ability of their claws.Support or Funding InformationNational Science Foundation (NSF) LEAP Scholars program
Estradiol’s Permissive Role in Social Stress Susceptibility in Female Rats
Authors: Pope Brittany , Mott Sarah E. , Fadel James R. , Wilson Marlene A. , Wood Susan K. 
Published: April 2020

Social stress is a common risk factor for both depression and cardiovascular disease (CVD), and individuals suffering from depression are at increased risk of CVD‐related mortality. Additionally, women are more likely than men to suffer from depression and anxiety along with comorbid CVD, however this increased risk is confined to the range between the beginning of puberty and end of menopause. Therefore, while specific systems regulating heightened susceptibility in females are unclear, there is evidence to suggest it may be regulated in part by ovarian hormones. Using a social stress model in female rats whereby a female is forced to witness a social defeat encounter between two males (15 mins, 5 days), we have previously shown that intact females are highly susceptible to this form of stress as evidenced by anxiety‐and depressive‐like behaviors, brain cytokines, and diminished vagal tone. Importantly, ovariectomized (OVX) females are resistant. Here we conducted two separate sets of studies to determine the role that 17‐β estradiol (17‐βE, 10μg/rat, sc) plays in susceptibility to social stress in females. In study #1, following ovariectomy and surgical implantation of cardiovascular transmitters (HD‐S11, DSI), rats were treated with either 17‐βE or vehicle and subjected to control or witness stress during cardiovascular recording. In study #2 all females were implanted with an i.v. catheter and either left intact (sham, and treated with vehicle) or OVX (and treated with vehicle or 17‐βE), followed one hour later by witness stress or control handling. Blood samples were collected (0, 15 and 60 mins) and behavior was video recorded. OVX females exhibited a blunted tachycardic response to stress that was reversed by 17‐βE administration. Moreover, epinephrine release in response to witness stress was highly reactive in intact females above that of OVX females, despite similar corticosterone levels. Anxiety‐like responses were also shown to be regulated by 17‐βE; witness stress‐evoked burying that emerged in intact females was blunted by OVX and reinstated by 17‐βE. Taken together these studies identify that proestrous levels of estradiol are critical for acute behavioral and cardiovascular responses to social stress in females. Future studies are aimed at determining the neural systems that are regulated by estradiol and precipitate stress susceptibility.Support or Funding InformationMH113892‐01A1, NARSAD Young Investigator Award 26809
Chronic sodium bicarbonate may promote metabolic dysregulation in a rodent model of CKD
Authors: Mannon Elinor , O'Connor Paul 
Published: April 2020

Chronic kidney disease (CKD) has no cure, and few treatment options targeted at slowing the decline in glomerular filtration rate (GFR). Several small clinical trials have indicated that oral sodium bicarbonate (NaHCO3) targets and slows the decline in GFR in CKD. The reported beneficial effects of NaHCO3 in this setting have led to its now common use clinically. It’s known however, that chronic alkali ingestion can promote potassium (K+) wasting, and that K+ depletion has been linked with metabolic dysregulation. Further, CKD patients who are supplemented chronically with oral NaHCO3 display significantly decreased plasma K+ levels relative to control treated counterparts, although these decreases in plasma K+ remain within normal range. No study has investigated the metabolic impacts of chronic NaHCO3 treatment and K+ wasting in CKD. To this end, we tested the hypothesis that in the setting of high tubular flow, chronic NaHCO3 ingestion would promote K+ wasting and metabolic dysfunction. In order to test our hypothesis, 9 male, 8 wk old Sprague Dawley (SD) rats underwent a 2/3 nephrectomy (Nx) and telemetry implantation. The 2/3 Nx is a model of reduced renal mass that has increased single nephron GFR in the absence of metabolic acidosis, similar to most human patients with CKD. Following 4 weeks of recovery, animals were given either 0.1M NaHCO3 (Bicarb, n=3), 0.1M NaCl (Vehicle, n=3) or 0.2M NH4Cl‐NaHCO3 (AC/B, n=3) in the drinking water for 12 weeks. Following 9 weeks of drinking water treatment, we observed a significantly higher hemoglobin A1c in our bicarb treated group compared to vehicle and AC/B treated groups (Bicarb 4.6 ± 0.1 vs Veh 4.2 ± 0.3 vs AC/B 4.2 ± 0.2; One‐way ANOVA, p=0.05). Following another 3 weeks of drinking water treatment, we performed blood gas measurements to assess plasma K+. In contrast to our hypothesis we observed the highest levels of plasma K+ in our bicarb treated animals compared to our vehicle or AC/B groups (Bicarb 5.18 ± 0.28 vs Veh 4.48 ± 0.66 vs AC/B 4.5 ± 0.21; One‐way ANOVA, p=0.16). Our data show that oral NaHCO3 could worsen blood glucose control in the setting of high tubular flow. Additionally, plasma K+ may not be a reliable measure for assessment of K+ status in CKD patients supplemented with NaHCO3. As the majority of K+ is stored intracellularly, further studies characterizing the effect of chronic alkali ingestion on total body K+ are warranted to assess the impact of NaHCO3 on K+ depletion in this patient population.Support or Funding InformationNIH PO1H134604 and DK099548
ER‐associated Regulation of Astrocyte Mitochondrial Function during METH and HIV‐1 Comorbidity
Authors: Proulx Jessica , Borgmann Kathleen 
Published: April 2020

Astrocytes are key regulators of central nervous system (CNS) health and neuronal function. However, astrocyte mitochondrial dysfunction, such as induced by METH and HIV‐1, threatens the ability of astrocytes to provide the essential metabolic and antioxidant support to neurons. Thus, being able to determine regulatory pathways that can be targeted to prevent aberrant mitochondria activity in astrocytes will be imperative for ensuring neuronal fitness/survival against CNS pathologies. The current investigation examined the endoplasmic reticulum (ER)‐mitochondrial interface in HIV‐1+ primary human astrocytes with and without METH exposure to characterize changes in mitochondrial bioenergetics, ER stress, Ca2+ signaling, and the regulation of mitochondria associated membranes (MAMs). Then, we explored the role of ER‐associated mechanisms in regulating astrocyte mitochondrial function. The effects of METH treatment were explored in both acute and chronic paradigms while responses to HIV‐1 were determined by transfecting astrocytes with a plasmid expressing whole HIV‐1 genome. Mitochondrial bioenergetics were then assessed using Seahorse Assay. Changes in the expression of unfolded protein response (UPR) and MAM mediators were determined using RT‐PCR and protein expression assays. Finally, pharmacological inhibition of Ca2+ signaling and UPR pathways were used to delineate the regulatory mechanisms mediating the changes in mitochondria bioenergetics. These findings illustrate the importance of ER‐mitochondria communication in regulating astrocyte mitochondrial function during METH/HIV‐1 pathogenesis.Support or Funding InformationThis project was supported by: R01 DA039789 & T32 AG020494‐16 A1 Neurobiology of Aging Fellowship
Aminoglycoside conformation and ring substituents dictate evasion from bacterial resistance mechanisms
Authors: Dey Debayan , Hoffer Eric D. , Francis Dillion , Dunham Christine M. , Conn Graeme L. 
Published: April 2020

Ribosomal RNA (rRNA) methylation by aminoglycoside‐resistance methyltransferases is presumed to reduce antibiotic activity by sterically occluding part of the drug binding site in helix 44 of 16S rRNA. However, for 4,6‐disubstituted deoxystreptamine (4,6‐DOS) aminoglycosides, the m1A1408 aminoglycoside resistance modification results in a wide range of bacterial resistance phenotypes with structurally similar drugs, from complete resistance to highly susceptible. Thus, for currently undefined reasons, some 4,6‐DOS aminoglycosides appear to be able to “evade” the effects of rRNA methylation at A1408. In contrast for the m7G1405 aminoglycoside resistance modification,
all 4,6‐DOS aminoglycosides are rendered inactive. Why these same drugs are unable to evade this methylation is also currently not mechanistically understood. We will describe the development of a framework for understanding methylated rRNA‐antibiotic interactions through the evaluation of energetics of drug‐methylated rRNA complexes for a collection of 4,6‐DOS aminoglycosides. With computational calculations using Monte Carlo simulations and free energy maps of aminoglycosides, we probed the flexibility around each ring’s dihedral angles (ϕ/ψ) in rRNA bound poses and the contributions of Ring I substituents to drug binding. These analyses revealed three key molecular features that may contribute to evasion of m1A1408 modification: 1) The polarity of atoms of the Ring I 6’ substituent; 2) the number of Ring I substituents; and 3) the presence of a L‐hydroxyaminobuteroyl amide (HABA) group on the 2‐DOS core ring. These studies lay a foundation for understanding aminoglycoside‐methylated rRNA interactions at the molecular level and could, for example, directly facilitate design of new aminoglycoside derivatives that retain activity against pathogens harboring aminoglycoside‐resistance rRNA methyltransferases.Support or Funding InformationThis work was supported by National Institutes of Health grants R01‐AI088025 (to GLC) and Cystic Fibrosis Foundation postdoctoral fellowship DEY18F0 (to DD).
Mutations In The Furin Cleavage Site To Improve Cytotoxicity In Anti‐Mesothelin Recombinant Immunotoxins Based On Pseudomonas Exotoxin A
Authors: Butters Keeley , Baker Jillian , Reifer Danielle , Weldon John 
Published: April 2020

A recombinant immunotoxin (RIT) is a fusion protein composed of an antibody and a toxin. The antibody binds to receptors on target cells and promotes internalization. Once internalized, the toxin kills the cell. RITs based on Pseudomonas exotoxin A (PE) have been created to target and kill cancer cells. In order to do this, internalized PE must reach the cytosol through a retrograde trafficking route, during which it encounters and is cleaved by the protease furin. Furin has been established as an integral part of PE‐based RIT intoxication pathways. Mutations in the PE furin cleavage site have been shown to influence cleavage efficiency and RIT cytotoxicity. In order to explore the role of furin in RIT intoxication further, we have constructed anti‐mesothelin/PE‐based RITs with mutations on either side of the furin cleavage site. Based on previous results, we initially hypothesized that mutations N‐terminal to the cleavage site would increase both cleavage efficiency and cytotoxicity in these RITs, while mutations C‐terminal to the cleavage site would increase cleavage efficiency without significant improvements to cytotoxicity. We expressed, purified, and tested the cytotoxicity of these constructs in tissue culture and found that mutations N‐terminal to the cleavage site decreased cytotoxicity relative to the wild‐type RIT, while mutations C‐terminal to the cleavage site had minimal effect. We next plan to explore cleavage efficiency of the mutant RITs.Support or Funding InformationTowson University Department of Biological Sciences
LPS Treatment Alters Oligodendrocyte Precursor Cell Migration
Authors: McKinley Raechel , Csoka Antonei B. 
Published: April 2020

The etiology of multiple sclerosis (MS), is characterized by the immune system attacking specialized cells within the central nervous system known as oligodendrocytes. Cytosolic projections of oligodendrocytes wrap their processes around axons to insulate them so that fast salutatory conduction of action potentials can occur. However, in MS, myelin is damaged, compromising axonal integrity and salutatory conduction. This destruction is thought to be a combination of many factors such as activation of inflammatory pathways and epigenetic mechanisms. One of the inflammatory pathways that is thought to be involved in the disease pathology of MS is the Toll‐like receptor (TLR) pathway that leads to the release of pro‐inflammatory cytokines such as TNF‐alpha, NFkB, and series of ILs. Together, these pro‐inflammatory cytokines have been shown to cause cells to undergo apoptosis and cell death. Moreover, it has been found in previous studies that there is increased TLR expression in the lesions of MS patients as well as Experimental Autoimmune Encephalomyelitis, which is an animal model used to study MS and other demyelinating diseases. Along with increased TLR expression in MS lesions, DNA methylation changes, such as increased hypermethylation and demethylation have also been found. Although there have been studies looking into TLRs and DNA methylation in MS lesions, understanding the mechanisms of TLRs in the development of new myelin during remyelination needs to be studied. Previously, we found that using lipopolysaccharide (LPS) to activate TLR2 and TLR4 in induced pluripotent stem cells (iPS) derived oligodendrocyte precursor cells (OPCs) resulted in the demethylation of several genes associated with neural and stem cell migration. In this study, we analyzed if TLR2 and TLR4 activation alters OPC migration. To do this, we performed a chemotactic assay in LPS and 5‐Azacytidine treated OPCs and found that TLR2 and TLR4 activation, along with inhibited methylation, results in increased OPC migration.Support or Funding InformationThis project was supported by the National Institute of Health (NIH) R25 Resource Grant (1 R25 AG047843‐01)
Sensitivity of Affective Pain Circuits to Inhibitory G Protein‐Coupled Receptor Signaling
Authors: Jaeckel Elizabeth , Herrera Yoani , Arias-Hervert Erwin , Perez-Medina Alberto , Sanchez-Conde Fransisco , Birdsong William T. 
Published: April 2020

Opioids modulate both sensory and affective components of pain, most significantly through agonist activity at the mu‐opioid receptor (MOR). While cellular mechanisms underlying opioid modulation of perception of stimulus intensity have been well characterized, mechanisms underlying opioid effects on pain‐related negative affect have not been well elucidated. The mediodorsal thalamus (MD) sends glutamatergic projections to the striatum as part of a thalamo‐cortical‐striatal loop that is involved in affective pain perception. Here, we determined the ability of various inhibitory coupled G‐protein coupled receptors (GPCRs), including MOR to inhibit glutamate release via presynaptic mechanisms. In mouse brain slices, MD terminals in the striatum were selectively activated using optogenetic techniques. Excitatory postsynaptic (EPSCs) were measured in striatal medium spiny neurons using whole cell patch‐clamp electrophysiology in the presence and absence of various inhibitory GPCR agonists. MOR full agonists met‐enkephalin (ME) and fentanyl, the delta opioid receptor agonist DPDPE, the adenosine A1 receptor agonist CPA, the GABAB receptor agonist baclofen, and the CB1 receptor agonist WIN 55,212 were tested. EPSC inhibition was seen with application of ME, fentanyl, CPA, and baclofen, indicating the presence of MORs, A1, and GABAB receptors. Inhibition was not seen with application of DPDPE or WIN 55,212, indicating delta opioid receptors and CB1 receptors are not present on these terminals. The effect of chronic opioid treatment on the function of these GPCRs will be discussed. Overall these data provide insight into how presynaptic GPCRs function to regulate neurotransmission in a circuit important for affective pain perception.Support or Funding InformationNIH T32‐DA007281R01DA042779
Small Molecule Inhibits Enterovirus 71 Replication by Targeting the IRES Domain
Authors: Davila-Calderon Jesse , Patwardhan Neeraj , Yuang-Chiu Liang , Sugarman Andrew , Cai Zhengguo , Penutmutchu Srinivasa , Li Mei-Ling , Brewer Gary , Hargrove Amanda , Tolbert Blanton S. 
Published: April 2020

Human Enterovirus 71 (EV71), one of the major etiological agents of the hand, foot, and mouth disease (HFMD), represents a serious global health threat against which there is no FDA‐approved treatment. Enteroviruses utilize a highly structured RNA domain, known as a type I Internal Ribosome Entry Site (IRES), to facilitate cap‐independent translation and genome replication by recruiting multiple host RNA‐binding proteins (ITAFs) that fine‐tune translation. Of particular interest, the stem‐loop II (SLII) IRES domain has been shown to specifically interact with several ITAFs such as hnRNP A1 and AUF1, having the SLII‐bulge as the binding surface to effectively modulate viral translation. Further studies showed that deletions and mutations to the bulge motif inhibit EV71 replication by offsetting IRES‐driven translation. Altogether, the results provide strong basis to classify the EV71 SLII domain as a promising target to develop novel antiviral agents. Here, we screened an RNA focused small molecule (rfsm) library against the EV71 SLII domain which yielded in the identification of six rfms that specifically bind to the bulge motif when detected by NMR spectroscopy and titration calorimetry. One of the aforementioned rfms impairs IRES‐dependent translation and displays dose‐dependent antiviral properties in cell culture. Furthermore, the NMR‐derived 3D structure of the SLII‐rfsm complex provides evidence that the small molecule binds to the bulge to induce a conformational change that exposes key nucleotides on the binding site for AUF1. This was further validated both in an in vitro biochemical assay and in vivo. Collectively, these results suggest an allosteric mechanism of inhibition in which the rfsm stabilizes the SLII‐AUF1 complex to repress translation. Therefore, this study provides structural and functional insight to develop novel RNA‐focused small molecule inhibitors of the Enterovirus genus.Support or Funding InformationNIH R01GM126833
Intestinal Gene Expression of Na+/HCO3− cotransporter 1 (nbce1) Isoforms in Atlantic Salmon During Smoltification and Seawater Acclimation
Authors: McKay Ian , Koltenyuk Victor , Lema Sean , McCormick Stephen , Breves Jason 
Published: April 2020

In preparation for migration from freshwater to marine habitats, Atlantic salmon undergo smoltification, a springtime transformation that includes the development of seawater tolerance. The ability of smolts to inhabit seawater is attained through the coordinated development of ion and water‐transporting processes in key organs such as the gill, kidney, and intestine. To promote solute‐linked water absorption, the intestinal epithelium of fishes acclimated to SW secretes HCO3− to form luminal Ca2+ and Mg2+ precipitates. As a source of HCO3− for apical anion exchange, Na+/HCO3− cotransporter 1 (Nbce1) facilitates the transport of plasma HCO3− into the interior of epithelial cells across the basolateral membrane. While Atlantic salmon (Salmo salar) express three nbce1 isoforms (nbce1.1, nbce1.2a, and nbce1.2b), there is no information on whether their expression corresponds with the development of intestinal fluid absorption that occurs during smoltification. We first determined that nbce1.1 and nbce1.2b gene transcripts were highly expressed in pyloric cacae and anterior intestine of smolts, whereas nbce1.2a showed low expression in the intestine but robust expression in gill. Next, we sampled salmon undergoing parr‐smolt transformation and observed elevated branchial Na+/K+‐ATPase activity in May characteristic of smoltification. Moreover, smolts exhibited an improved ability to maintain ionoregulatory balance when transferred to seawater in May versus March. We will report corresponding patterns of nbce1.1 and nbce1.2b expression in pyloric cacae and anterior intestine during smoltification and following seawater transfer to resolve whether their transcriptional patterns correspond with the acquisition of intestinal fluid absorptive processes.Support or Funding InformationSupported by the National Science Foundation (IOS‐1755131).