bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Kölliker‐Fuse nucleus drives respiratory modulation of cardiac vagal tone (686.15)
Authors: Farmer David , Dutschmann Mathias , Paton Julian , Pickering Anthony , McAllen Robin 
Published: June 2021

Cardiac vagal tone is a major determinant of health, but its origin is unknown. It is present and well developed in the decerebrate perfused working heart‐brainstem preparation (WHBP) of rat, indicating that it arises from within the brain stem. Direct recordings from the cardiac vagal branch in the WHBP (juvenile rats day 17‐25, n=10) showed spike activity that peaked in late inspiration/postinspiration, correlating with the bradycardia of respiratory sinus arrhythmia (RSA). Bilateral inhibition of neurons in the Kölliker‐Fuse nucleus (KF) of the pons by microinjections of the GABAA receptor agonist, isoguvacine (10 mM, 40‐60nl), abolished the post‐inspiratory peak but had little effect on mean cardiac vagal nerve activity. That activity assumed a tonic pattern, interrupted by brief pauses around the onset of inspiration. RSA was abolished, and heart rate rose modestly (~ 20 beats/min). Transection of the caudal pons at the level of the facial nuclei substantially reduced mean cardiac vagal activity (50‐80%) and raised heart rate substantially (~ 50 beats/min). These results indicate that cardiac vagal tone is distinct from RSA, though both depend on supramedullary connections. Drive from the KF is responsible for RSA, while the origins of most cardiac vagal tone remain to be determined.Grant Funding Source: ARC
Disinhibition of the pontine and dorsal respiratory groups reveals postinspiratory pacemaker activity (714.2)
Authors: Dutschmann Mathias , Bautista Tara 
Published: June 2021

The ‘pontine respiratory group’ in dorsolateral pons overlaps with the Kolliker‐Fuse nucleus (KF) while the ‘dorsal respiratory group’ is associated with ventrolateral areas of the nucleus of the solitary tract (NTS). The contribution of both to the generation of the eupneic respiratory motor pattern remains controversial. This study describes the severe disruption to normal breathing following focal microinjection of bicuculline (GABAA receptor antagonist) into the KF and NTS in the juvenile in in situ preparation of rat. Disinhibition of the KF produced an increased variability in the sequential patterning of the eupneic 3‐phase respiratory motor pattern. The chaotic respiratory pattern after KF disinhibition is largely associated with instability of postinspiratory gating mechanisms. In contrast, disinhibition of the NTS caused repetitive barrages of rhythmic, non‐swallow related discharges in vagus nerve that suppressed inspiratory activity. These rhythmic discharges were likely pacemaker‐driven since they were abolished by the persistent sodium channel blocker riluzole. Moreover, riluzole microinjection into KF or NTS alone triggered delayed inspiratory off‐switch, suggesting that pacemaker currents indeed contribute to the timing of postinspiratory mediated inspiratory off‐switch and respiratory motor patterning.Grant Funding Source: ARC
Characterization of tauopathy in the ponto‐medullary brainstem nuclei of aged Tau‐P301L mice (728.7)
Authors: Stanic Davor , Bautista Tara , Dutschmann Mathias 
Published: June 2021

Neurodegenerative diseases, such as Alzheimer’s disease (AD) and dementia, are often linked to swallowing disorders such that aspiration pneumonia resulting from accidental inhalation of ingested material is a common phenomenon. Growing evidence suggests that malfunction in the coordination of swallowing and breathing leads to increased risk of aspiration. We investigated the underlying pathology linking dementia and swallowing dysfunction in Tau‐P301L transgenic mice, an established mouse model of neurodegeneration. Tauopathy and neurofibrillary tangle‐related neuropathological morphology in the brainstem of 10‐month old Tau‐P301L mice was identified by immunohistochemistry using antisera against: 1) pre‐neurofibrillary tangles (Tau phosphoThreonin 231); and 2) extra‐neuronal neurofibrillary tangles (Tau phosphoSerine 199/202). Cell bodies containing diffuse phospho‐tau‐immunoreactivity within the cytoplasm, together with preserved, collapsed or absent dendrites were identified in the Kölliker‐Fuse (KF) nucleus, ventral swallowing group (VSG) dorsomedial to the nucleus ambiguus, and nucleus of the solitary tract (NTS), regions known to co‐ordinate breathing and swallowing. Our results suggest that neurons in the KF, VSG and NTS are susceptible to neurodegeneration, and provide a platform for examining the effect of tauopathy in functionally defined and experimentally controllable brainstem circuits (for swallowing and breathing). This may facilitate a framework for the development of potential drug therapies for neuroprotection and prevention of aspiration and dementia.Grant Funding Source: ARC
Characterization of RPA‐protein interactions and their dependence on the phospho‐mimetic state of the N‐terminus of Saccharomyces cerevisiae Rfa2 (735.13)
Authors: Mueller Erica , Piya Gunjan , Severson Amber , Haring Stuart 
Published: June 2021

Replication protein A (RPA) is a heterotrimeric complex in all eukaryotic cells that is essential for DNA replication, repair/recombination, and cell cycle regulation. A common intermediate of each of these DNA processes is the formation of single‐stranded DNA (ssDNA) and the major biochemical function of RPA is to bind to ssDNA. Therefore, RPA not only acts as a sensor of incomplete duplex DNA, but also as a recruiter of factors necessary to process this intermediate. It is clear that RPA interacts with a number of proteins; however, many of these interactions have not been well characterized in yeast, making unclear the physiological role of each RPA‐protein interaction in cellular DNA metabolism.It is well known that in response to DNA damage, the N‐terminus of the human 32‐kDa subunit (Rpa2) becomes phosphorylated, and this has been demonstrated to modulate some RPA‐protein interactions. Although phosphorylation of the Rfa2 N‐terminus has not been definitively demonstrated during the DNA damage response, we have demonstrated in our lab that phospho‐mutant forms of the budding yeast Rfa2 N‐terminus show DNA damage‐dependent phenotypes. Therefore, we hypothesize that the phosphorylation state of Rpa2 (or Rfa2) coordinates the response to DNA damage through regulation of RPA‐protein interactions. The goals of this research were: 1) to identify yeast RPA‐protein interactions, 2) to map regions important for protein interaction, and 3) to characterize whether these protein interactions are dependent on the phosphorylation state of the Rfa2 N‐terminus We have identified a number of RPA‐protein interactions that are dependent on the state of the Rfa2 N‐terminus, and we have mapped the region(s) of RPA that are important for some of these interactions. This combined data suggests potential models for how the Rfa2 N‐terminal phosphorylation state may be regulating protein interactions to coordinate RPA cellular function.Grant Funding Source: Supported by NIH, NIJ, NSF
Probing the role of the E304 and P288 residues in the allosteric site of Agrobacterium tumefaciens ADPglucose pyrophosphorylase (769.19)
Authors: Karzai Hoomai , Bor Simona , Benjamin Vonice , Silva Emmanual , Meyer Christopher 
Published: June 2021

ADP‐glucose pyrophosphorylase (ADPG PPase) is the rate limiting enzyme in the glucan biosynthesis pathway, a vital source for renewable and biodegradable carbon. Thus ADPG PPase is an attractive target for protein engineering to produce a more active enzyme to increase the biomass. Agrobacterium tumefaciens (Ag. t) ADPG PPase is activated by F6P and pyruvate and inhibited by phosphate and sulfate via common allosteric site(s). The Ag.t ADPG PPase structure (pdb: 3BRK) indicates that the E304 residue is part of the allosteric site. The P288 residue, which is part of the loop region connecting the N‐terminus domain to the C‐terminus domain, is also involved in allosteric regulation. To probe the roles of these two residues the E304A, E304D, and P288E enzymes were generated, purified and kinetically characterized. The purification scheme included Phenyl Sepharose, anion exchange (DEAE or UNO Q), and Blue A chromatography. Substitution of the P288 residue resulted in changes in allosteric behavior with the largest effects being desensitization to activators as well as higher activity in the absence of activators. A decrease in Vmax as well as stability was observed in the P288E mutant in both the absence and presence of activators. Substitution of the E304 residue also resulted in changes in allosteric behavior with the largest effect being desensitization to both activators and inhibitors. The E304D mutant displayed a higher Vmax (~2.5‐fold) in the absence of activators and it was activated by FBP, a gain of function compared to wild type (WT). Future studies include the characterization of E304N and the generation and characterization of K310A (in the presence and absence of P288D) as this residue may be forming a salt bridge with the introduced aspartate residue. Efforts to crystallize the P288D enzyme are underway to compare to the WT structure.Grant Funding Source: Supported by NSF award 0448676
Everyone Needs Folic Acid is a digital program with face and content validity for low‐income diverse audiences (807.4)
Authors: Cheng Feon , Wamboldt Patricia , Lohse Barbara 
Published: June 2021

Everyone Needs Folic Acid, a nutrition program delivered with a digital photo frame platform, was developed to help low‐income persons appreciate the role of folic acid (FA) for all age groups. Program assessment was conducted in 2 stages: Stage 1 focused on the original program and Stage 2 evaluated the subsequent program revisions. Participants (n=73) were white (97%), overweight or obese (43%), not eating competent (73%), and had at least 2 children (53%). The sample was low‐income; 42% used at least 1 assistance program in the past year and 27% were SNAP participants. The original program was easy to read (90%), understandable (87%), and helpful (66%). Suggested improvements were to provide dosage information, increase pictures of folic acid rich foods, and reduce message redundancy. Stage 2 participants (n=50) were recruited from the Stage 1 sample. When asked if they recalled any information about the original program 27% of Stage 2 respondents remembered a lot, 45% remembered some, and 28% reported little or no information recall. 72% had applied information to themselves or their family and 96% indicated that they would recommend this program to others. Participants compared 6 original with revised slides and preferred the original in 2 pairs, the revised slide in the other 4. Everyone Needs Folic Acid demonstrated face and content validity for SNAP‐eligible persons. Funded by USDA, SNAP Ed.Grant Funding Source: USDA, SNAP Ed
Association between serum and brain fatty acid profiles in centenarians (821.2)
Authors: Mohn Emily , Vishwanathan Rohini , Lichtenstein Alice , Matthan Nirupa , Poon Leonard , Johnson Mary Ann , Hausman Dorothy , Davey Adam , Green Robert , Gearing Marla , Woodard John , Nelson Peter , Miller L , Johnson Elizabeth 
Published: June 2021

Profiles of brain fatty acids (FA) may be important indicators of age‐related cognitive decline. There is limited data on brain FA profiles in centenarians. Serum FA may be related to brain FA profiles. The goal of this study was to test this hypothesis in centenarians. Tissue from the frontal, occipital, temporal cortices, and cerebellum were collected from decedents (n=40) in the Georgia Centenarian Study with available banked serum. Brain and serum FA were measured using gas chromatography. FA profiles were different between serum and brain (P<0.0001). On average, saturated FA (SFA) were predominant in the brain (47 mol%), followed by monounsaturated FA (MUFA) (23 mol%), n‐3 polyunsaturated (n‐3) FA (14 mol%, with 91% being docosahexaenoic acid), n‐6 polyunsaturated (n‐6) FA (12 mol%), and trans FA (0.7 mol%). N‐6 FA were highest in serum (38 mol%), followed by SFA (30 mol%), MUFA (25 mol%), n‐3 FA (3 mol %), and trans FA (3 mol%). Serum n‐3 FA were related to brain levels in the frontal (r=0.43, P<0.01) and temporal (r=0.35, P<0.05) cortices and cerebellum (r=0.41, P<0.05). Serum n‐3/n‐6 was related to brain n‐3/n‐6 in all regions (frontal: r=0.41, occipital: r=0.38, P<0.05; cerebellum: r=0.47, temporal: r=0.55, P<0.01). No other FA were related between serum and brain. The data suggest that both n‐3 FA and n‐3/n‐6 FA can be used as markers of brain fatty acid profiles.Grant Funding Source: Supported by: USDA (58‐1950‐0‐014), NIH (1P01‐AG17553), and Abbott Laboratories
Role of metabolism and intracellular trafficking in fructose‐induced GLUT5 regulation (822.4)
Authors: Patel Chirag , Douard Veronique , Tharabenjasin P , Topaktas E , Ferraris Ronaldo 
Published: June 2021

Marked increases in fructose consumption have been linked to various diseases. Fructose (F) upregulates its own absorption by increasing the expression & activity of the intestinal F transporter GLUT5, but the underlying mechanism is not well understood. Defects or limits in regulation can lead to adult‐onset F intolerance or to F malabsorption in infants. I tested the hypothesis that F transport via GLUT5, metabolism via ketohexokinase (KHK), and GLUT5 intracellular trafficking to the apical membrane via the GTPase Rab11a are required for GLUT5 upregulation. WAdult wildtype (wt), GLUT5‐/‐, and KHK‐/‐, and Rab11a‐/‐ mice were receivedreceiving 30% glucose (G), fructose (F) or lysine (L) by gavage twice a d for 3 d at X.X ml/kgays. 17 d old wt and Rab11a‐/‐ mice were gavaged with either 30% G or F. Afterwards, GLUT5 activity as well as mRNA and protein expression determined in the small intestine. Activity and expression of GLUT5 and of other enzymes involved in F metabolism increased in F‐gavaged mice compared to those gavaged with G or L. This effect was specific because expression of unrelated transporters like SGLT1 did not change. Strikingly, F failed to induce the expression & activity of GLUT5 and of other enzymes involved in F metabolism, in KHK‐/‐, GLUT5‐/‐ and Rab11a‐/‐ mice. Thus, I have demonstrated for the first time the essential roles of membrane transport, metabolism, and Rab11a‐mediated trafficking in F‐ induced GLUT5 upregulation.Grant Funding Source: NSF IOS‐1121049.
Radiofrequency renal nerve denervation decreases blood pressure, sympathetic activity and renal norepinephrine content in spontaneously hypertensive rats (875.16)
Authors: Gao Juan , Kerut Edmund , Smart Frank , Kapusta Daniel 
Published: June 2021

Radiofrequency renal denervation (RF‐RDN) decreases blood pressure (BP) in patients with drug‐resistant hypertension. This study investigated the effects of RF‐RDN on sympathetic activity and BP (Systolic, SBP; Diastolic, DBP) in SHR. Methods Nineteen‐week old male SHR were instrumented with telemetry probes for chronic measurement of BP and BP variability (BPV). After 1‐week, control BP was measured in rats for 3 days. The next day SHR (n=6/group) were anesthetized and randomly received either bilateral Sham‐RDN or RF‐RDN of the renal arteries (Biosense Webster Stockert 70 generator and RF‐probe). BP was then measured in SHR for 8 weeks. Results Following RF‐RDN, SBP/DBP was significantly decreased the day after (153±8/102±4 mmHg) and throughout the post‐RDN study (4‐week SBP/DBP, 173±7/120±5; 8‐weeks, 171±6/116±4 mmHg) compared to pre‐RDN control levels (SBP/DBP, 187±9/130±5 mmHg). RF‐RDN significantly decreased the low frequency component of BPV in SHR with the peak attenuation observed at 8 weeks (LF/HF 2.2±0.2 vs 0.9±0.2); this correlated with a blunting of the hypotensive response to i.p. chlorisondamine in RF‐RDN rats. Finally, at the end of week 8, kidney norepinephrine (NE) levels in RF‐RDN rats (left, 10±10; right, 0.0±0.0 ng/g kidney) were dramatically decreased compared with levels from sham SHR (left, 130±10; right, 110±10 ng/g kidney). Conclusions These data demonstrate that in hypertensive SHR, bilateral RF‐RDN of the renal arteries decreases BP in part by chronic inhibition of sympathetic neural pathways and a decrease in renal tissue NE levels.Grant Funding Source: Biosense Webster grant IIS‐175 to DRK and FS; NIH NIGMS P20 GM103514 to DK
Electrocardiographic markers for cardiac hypertrophy in mice bred for high voluntary wheel running (881.11)
Authors: Kay Jarren , Hampton Thomas , Garland Theodore 
Published: June 2021

The left ventricle becomes enlarged during cardiac hypertrophy, caused by either physiological or pathological factors. Electrocardiogram (ECG) recordings can provide insights into cardiac hypertrophy. We used 100 mice from an ongoing experiment which breeds for high voluntary wheel running. ECGs were recorded before and after 6 days of wheel access using an ECGenie (Mouse Specifics, Quincy, MA). After wheel access, and adjusting for body mass, mice from the four replicate High Runner lines had significantly lower heart rates than those from the four non‐selected Control lines (650 ± 30 bpm vs. 709 ± 14 bpm, LSM ± SE, p<0.05); females had a shorter PQ interval duration than males (19.2 ± 0.3 ms vs. 20.9 ± 0.8 ms, p<0.05). A subset of the HR mice are homozygous for a recessive mutation that causes the mini‐muscle (MM) phenotype, characterized by a ~50% reduction in hindlimb muscle mass and larger hearts than wild types. MM mice had longer PQ intervals after wheel access, and a longer QRS complex compared to Control both before (11.1 ± 0.3 ms vs. 10.2 ± 0.1 ms, p<0.05) and after wheel access (11.2 ± 0.3 ms vs. 10.5 ± 0.1 ms, p<0.05). The longer QRS duration in the MM mice before wheel access points to left ventricular hypertrophy, but whether this is a physiological adaptation to selective breeding or a pathological state requires further study. MM ventricular hypertrophy may be a useful model of cardiac enlargement in human athletes.Grant Funding Source: NSF IOS‐1121273
Sex differences in the ability of high fat diet to inhibit glucose‐induced modulation of 5‐HT3 receptor responses in GI‐vagal afferents in rats (905.4)
Authors: Troy Amanda , Browning Kirsteen 
Published: June 2021

Previous studies in this lab have shown that extracellular glucose modulates 5‐HT3 receptor (5‐HT3R) mediated currents GI vagal afferent neurons and that this response is lost following exposure to a high fat diet (HFD). The aim of this study was to investigate whether this loss of glucose‐induced modulation showed any sex dependent differences.Sprague‐Dawley rats were placed on HFD (60% kcal from fat) at 28 days. Whole cell patch clamp recordings were made subsequently from acutely dissociated identified GI‐projecting vagal afferent neurons. The ability of extracellular glucose (2.5‐10mM) to modulate the magnitude of the 5‐HT‐induced inward current was assessed.After 4 weeks HFD exposure, glucose modulated the 5‐HT‐induced response in 7/8 neurons (87%) from female rats. In contrast, glucose modulated the 5‐HT‐induced inward current in only 4/7 neurons (57%; 4 weeks) from male rats (P<0.2). At this time point, there was no difference in body weights (male: 189±12g vs female: 168±5g; P>0.05) although male rats had significantly higher blood glucose levels (363±13mg/dl vs 251±7mg/dl; P<0.05). These data suggest that, following HFD (i) male rats may be more susceptible to loss of glucose‐induced modulation of 5‐HT‐induced currents in GI vagal afferent neurons and (ii) this loss of glucose‐induced modulation is determined primarily by dysregulated glycemic control rather than diet or obesity.Grant Funding Source: NIH DK078364, NSF IOS1148978
Substrate recognition and processing by the eukaryotic 26S proteasome (936.3)
Authors: Bashore Charlene , Martin Andreas 
Published: June 2021

The 26S proteasome degrades a multitude of substrates and is essential for eukaryotic cell survival. The 2.5 mega‐dalton protease processes substrates through its 19S regulatory particle: this intricate complex binds, unfolds, and feeds substrates into the proteasomal peptidase, where they are irreversibly degraded. Although the mechanism of proteasome proteolysis has been well characterized, little is known about how the processing steps prior to degradation culminate to give an overall degradation rate. The complexity of substrate processing and the requisite of proteasome function for cell viability pose a significant challenge to quantitative analysis. I have developed an in vitro system to measure degradation and deubiquitination rates as a function of substrate thermodynamic stability and lysine placement. These tools lend insight on the rate limiting step in substrate degradation and how polyubiquitin tags are recognized and processed by this intricate proteolytic machine.Grant Funding Source: Supported by the National Science Foundation
Messenger RNAs and cognate microRNAs in the nucleolus (940.3)
Authors: Reyes‐Gutierrez Pablo , Politz Joan , Pederson Thoru 
Published: June 2021

During studies of muscle cell differentiation in a rat myogenic cell line we discovered, to our surprise, that several microRNAs are concentrated in the nucleolus (Politz et al., PNAS 103: 18957‐18962, 2006; RNA 15:1705‐1715, 2009). Since these nucleolus‐localized microRNAs were also present in the cytoplasm, it seemed plausible that their association with nucleoli represented a station on their nuclear export pathway. These findings prompted us to ask whether certain messenger RNAs might also localized in the nucleoli of these cells. Microarray analysis of RNA from highly purified nucleoli revealed a set of mRNAs present at 30 to 650‐fold higher concentrations than in the nucleoplasm and this was confirmed by in situ hybridization for one of these mRNAs, that encoding insulin‐like growth factor 2 (IGF2), an well‐known autocrine regulator of myoblast proliferation and differentiation. RT‐PCR experiments demonstrated that these nucleolus‐localized IGF2 transcripts are spliced mRNAs, suggesting that they arrive from distal sites in the nucleoplasm. Bioinformatics analysis predicted stable interactions between all of the nucleolus‐localized microRNAs and the 5′ or 3′ untranslated regions of IGF2 mRNA. Additional considerations suggest that at least one of the nucleolus‐localized microRNAs, miR‐206, may be involved in the positive regulation of IGF2 mRNA translation and we speculate that transit through the nucleolus commits IGF2 mRNA to this mode of regulation.Grant Funding Source: NSF MCB‐1051398
A comparative study of xanthine dehydrogenase regulator proteins in Agrobacterium tumefaciens and Streptomyces coelicolor (946.3)
Authors: Sivapragasam Smitha , Grove Anne 
Published: June 2021

A. tumefaciens and S. coelicolor are among the most studied bacteria with the former being the 3rd most important plant pathogen. The transcription factor XdhR of S. coelicolor (ScXdhR) regulates its own gene expression along with the divergently oriented xanthine dehydrogenase ABC (xdh) gene cluster. A similar genomic locus was observed in A. tumefaciens. Xanthine dehydrogenase converts hypoxanthine and xanthine to urate. Based on elecrophoretic mobility shift assays we show that ScXdhR and XdhR of A. tumefaciens (AtXdhR) bound to their respective intergenic regions specifically but with different binding affinities. The ligands GMP, rGTP and xanthine compromised the DNA‐XdhR binding in both cases. The ScXdhR‐DNA complex also dissociated upon addition of H2O2, cumene hydroperoxide and tert‐butyl hydroperoxide, whereas DNA binding by AtXdhR was unaffected. SDS‐PAGE analysis revealed that ScXdhR dimerized upon addition of these oxidants, whereas AtXdhR did not. AtXdhR dimerized in the presence of Co2+ whereas ScXdhR did so in the presence of Cu2+ as well as Co2+. This study suggests that both XdhR proteins may regulate expression of the xdh gene cluster in response to intermediates in the purine degradation pathway. Notably, ScXdhR also responds to oxidation, suggesting upregulation of xdh during oxidative stress.Grant Funding Source: NSF