bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nematode hexosaminidases – a new biochemical tool for glycan analysis
Authors: Dutkiewicz Zuzanna , Yan Shi , Vanbeselaere Jorick , Paschinger Katharina , B.H. Wilson Iain 
Published: May 2022

Hexosaminidases are ubiquitous enzymes with multiple roles in glycoconjugate metabolism as they remove non‐reducing terminal β ‐N‐acetylhexosamine residues from glycans, glycolipids, glycoproteins and glycosaminoglycans. Amongst many functions in non‐invertebrates, hexosaminidases are involved in maturation of N‐glycans.Previous studies of Caenorhabditis elegans Hexosaminidases (Gutternigg, 2007; Dragosits, 2014) prove that this organism possesses five GH20 family genes: four belong to the subfamily 1: HEX‐2; ‐3; ‐4 and ‐5, one to subfamily 2: HEX‐1. C. elegans HEX‐4 was recently shown to remove terminal GalNAc even from structures in which the underlying GlcNAc was substituted with phosphorylcholine. Now, we have begun to characterize hexosaminidase orthologues from pig parasitic nematodes, specifically Oesophagostomum dentatum, Trichuris suis and Trichinella spiralis. Bioinformatics analyses indicate that T. suis and T. spiralis have only two GH20 genes, one orthologous to HEX‐1 and one paralogous to the HEX‐2‐5, whereas the genome of O. dentatum appears to contain one orthologue each of HEX‐1‐5. Phylogenetic analyses are, however, complicated by incorrect database annotations in most nematode species.In terms of in vitro characterisation, the subfamily 1 GH20 enzyme from T. suis was expressed in yeast and observed to favor pNP‐β‐GalNAc with a pH optimum of 6.5; however, it can remove a single GlcNAc from the a1,3‐mannose of the N‐glycan substrate GnGn‐PA, as well as both GalNAc residues from a biantennary LacdiNAc‐containing structure. Thus, this enzyme appears to have the properties akin to both HEX‐2 and HEX‐4 from C. elegans. Homology‐based 3D‐structure prediction of hexosaminidases from C. elegans and T. suis showed no significant differences in the substrate binding pocket.In summary, nematode hexosaminidases have distinct substrate specificities and different numbers of homologues per species exist. These nematodes enzymes are not only interesting due to their roles in glycan biosynthesis; due to their specificities, they are useful as a complement to mass‐based glycomic workflows.
Exercise and Hypercapnia Differentially Modify Ratios of Extracranial and Intracranial Pulsatility
Authors: DuBose Noah , Ainslie Philip N. , Sherman Sara R. , Baynard Tracy , Hoiland Ryan , Smith Kurt J. , Green Daniel J. 
Published: May 2022

INTRODUCTIONDamping of pulsatile flow between extracranial and intracranial cerebral arteries is an essential allostatic mechanism protecting cerebral microvessels from recalcitrant hemodynamics. The ratio of pulsatility between proximal and distal cerebral arteries may provide a measure of cerebrovascular hemodynamic damping. This might prove useful as an evaluation of cerebrovascular regulation in response to pulsatile perturbations.PURPOSETo characterize cerebral pulsatile damping between extracranial and intracranial environments in response to perturbations eliciting matched shear stress, such as exercise and hypercapnia.METHODSParticipants (n=10) completed two 30‐min experimental conditions aimed at matching cerebral artery shear stress, each separated by 48 hrs: (1) mild hypercapnia (CO2; FICO2:0.045) and (2) submaximal cycling (EX; 60%HRreserve). Cerebral pulsatility index (PI: (systolic velocity‐diastolic velocity)/mean velocity)) was assessed at baseline, during, and following each condition in the internal carotid artery (ICA) and middle cerebral artery (MCA) using Doppler ultrasound. Heart rate (HR) and blood pressure (BP) were assessed continuously using ECG and photoplethysmography, respectively. Cerebral pulsatile damping was calculated: (ICA PI / MCA PI) to investigate ratios of cerebral pulsatile hemodynamics between extracranial and intracranial arteries.RESULTSCerebral pulsatile damping was greater during CO2 (1.66 ± 0.31) than EX (1.22 ± 0.35) (time*condition effect, p=0.002). The change in cerebral pulsatile damping was related to the change in heart rate (r = ‐0.70, p = 0.04), but not BP between baseline and the experimental conditions.CONCLUSIONSAs evidenced by the response in cerebral pulsatile damping, exercise and hypercapnia result in different ratios of extracranial to intracranial pulsatility despite inducing similar vasodilation when shear stress was matched. This might in part be explained by differences in HR between conditions. Further research is important to elucidate the mechanisms behind the deviance in hemodynamic responses.
Processing of DNA Clamp Loader Subunit DnaX Is Important in the Absence of Caulobacter Cell Division Inhibitors
Authors: Tashjian Tommy F. , Chien Peter 
Published: May 2022

The DNA clamp loader is critical to the processivity of DNA replication and to the coordination of synthesis on the leading and lagging strands. In bacteria, the major subunit of the clamp loader, DnaX, has two forms: the essential full‐length DnaX tau and a shorter DnaX gamma. These forms are conserved across bacterial species and three distinct mechanisms have been found to create them such as ribosomal frameshift or transcriptional slippage. In Caulobacter crescentus, the full‐length DnaX tau is partially proteolyzed by ClpXP into two shorter DnaX gamma forms. Despite being discovered over 30 years ago, the purpose of maintaining multiple DnaX forms is unknown.To examine the purpose of encoding two forms, we created a nonproteolyzable allele of DnaX (tau‐only) which had no observable growth or morphological defects but showed a mild sensitivity to DNA damage. Adding an additional plasmid encoded copy of dnaX(tau‐only) to the dnaX(tau‐only) strain causes growth defects, filamentation, and increased RecA induction. These defects are not observed when adding a plasmid copy of dnaX(tau‐only) to the wild type strain, suggesting that an excess of DnaX tau is toxic, and likely causes replication stress.To better define the pathways that are affected in the absence of DnaX gamma, we performed transposon sequencing analysis to identifying genes that cause synthetic interactions with the dnaX(tau‐only) allele. We found that the insertions in two cell division inhibitors, sidA and didA, were underrepresented in the dnaX(tau‐only) strain compared to wild type. Consistent with this finding, we observed that adding a plasmid copy of dnaX‐tau‐only in a ΔsidA or ΔdidA strain causes an extreme growth defect and filamentation. Interestingly, although sidA is expressed as part of the RecA/LexA‐dependent DNA damage response in Caulobacter, we do not see a similar filamentation when we add an exogenous copy of the dnaX‐tau‐only allele to a ΔrecA strain. This indicates that the uninduced level of sidA expressing is sufficient to suppress the growth and filamentation phenotypes. The observation that cell division inhibitors are critical in the absence of proper DnaX processing suggests that the coordination of DNA replication and cell division is not intact in the dnaX‐tau‐only allele.
A protein mutated in Parkinson's disease prevents damage of metabolites and proteins caused by a glycolytic metabolite
Authors: Heremans Isaac P. , Caligiore Francesco , Gerin Isabelle , Bury Marina , Lutz Marilena , Graff Julie , Stroobant Vincent , Vertommen Didier , Teleman Aurelio , Van Schaftingen Emile , Bommer Guido T. 
Published: May 2022

The accumulation of cellular damage is suspected to contribute to aging and neurodegenerative diseases. Oxidative stress and environmental factors likely play a role, but other damaging agents likely remain to be discoveredHere we report that an enzyme mutated in hereditary Parkinson’s disease achieves the seemingly impossible task to prevent damage caused by a glycolytic metabolite without affecting the metabolite itself. Inactivation of this enzyme in model systems ranging from flies to human cells leads to the accumulation of a wide range of metabolites and proteins damaged by a newly discovered covalent modification.Thus, this enzyme represents a highly conserved strategy to prevent damage in cells that perform glycolysis. Thereby, it interrupts a fundamental link between carbohydrate metabolism and a type of cellular damage that might contribute to the development of Parkinson’s disease.
Distinct Effects of Mesterolone on Oxidative and Glycolytic Fibers of Avian Skeletal Muscle
Authors: Allouh Mohammed Z. , Ouda Zakaria H. , Ouda Sara H. 
Published: May 2022

AimOxidative and glycolytic muscle fibers differ in their responses to physiological stimuli and pathological insults. We examined whether these fibers respond differentially to exogenous anabolic androgenic steroids (AASs) by comparing morphological and histological changes between the oxidative anterior latissimus dorsi (ALD) and glycolytic pectoralis major (PM) fibers in adult avian muscles.MethodsThe AAS mesterolone was selected for this study. Mesterolone is a synthetic steroid that has no estrogenic side effects, low hepatotoxicity, and confers oral activity that allows its oral route of administration. Adult female White Leghorn chickens (Gallus gallus) were randomly divided into five groups: a vehicle control and four mesterolone treatment groups (4, 8, 12, and 16 mg/kg). Mesterolone was administered orally every three days for 4 weeks. Immunocytochemical techniques and morphometric analyses were employed to measure the changes in muscle weight, fiber size, satellite cell (SC) composition, and number of myonuclei.ResultsMesterolone increased both body and muscle weights and induced hypertrophy in glycolytic PM fibers but not in oxidative ALD fibers. Mesterolone induced SC proliferation in both muscles; however, the myonuclear accretion was noticeable only in the PM muscle. In both muscles, the collective changes maintained a constant myonuclear domain size and the changes were dose independent.ConclusionMesterolone induced distinct dose‐independent effects in avian oxidative and glycolytic skeletal muscle fibers; these findings might be clinically valuable in the treatment of age‐related sarcopenia.
A Common Alpha Globin Gene Deletion is Associated with Decreased Arterial Alpha Globin Gene Expression and Altered Vasoreactivity among Black Americans
Authors: Brooks Steven D. , Zeng Xianke , Jackson Mary , Tesfuzigta Naomi , Laurence Kyeisha , Nino de Rivera Jessica , Jackson Jarrett , Emeh Robert , Smith Rachel , Kamenyeva Olena , Ganesan Sundar , Kabat Juraj , Cruz Phillip , Joyce Stacy , Davis Jeremy , Ruhl A. Parker , Ackerman Hans 
Published: May 2022

Alpha globin binds to endothelial nitric oxide (NO) synthase (eNOS) and limits the diffusion of NO from endothelial cells into vascular smooth muscle. Previously, we demonstrated that pharmacologic disruption of alpha globin‐eNOS binding enhanced NOS‐dependent vasodilation in human arteries. Here, we explore the hypothesis that individuals with alpha globin gene deletions will have reduced alpha globin gene expression in resistance arteries and altered arterial vasoreactivity.To test this hypothesis, we screened healthy Black Americans (clinical trial # 02692872) for a common 3.7 kb gene deletion in the alpha globin gene locus (HBA) that reduces the number of functional gene copies. We excluded people with risk factors for cardiovascular disease and created a nested case control study that included 15 people with four copies, 8 people with three copies, and 2 people with two copies of HBA. Each individual underwent an incisional subcutaneous adipose biopsy (clinical trial # 03937817), from which we isolated resistance arteries less than 200 μm in diameter. Resistance arteries were cannulated and perfused free of blood before undergoing multiphoton imaging, gene expression analysis, or pressure myography.Multiphoton imaging of adipose resistance arteries revealed alpha globin to co‐localize with eNOS near the myoendothelial junction between endothelial and smooth muscle cells. Arteries from individuals with three functional copies of HBA had lower expression of HBA compared to arteries from individuals with four functional copies of HBA(1715 copies/ng cDNA vs 1176 copies/ng cDNA, p = 0.03). The concentration of phenylephrine required to constrict the human adipose arteries to 50% of baseline was 8 times greater for arteries from subjects with three copies of HBA compared to arteries from subjects with four copies of HBA (log10[EC50]: ‐4.78 (95% CI: ‐4.29 to ‐5.22) vs ‐5.68 ± (95%CI: ‐5.33 to ‐5.98) p = 0.003). Arteries from individuals with three copies of HBA also had reduced maximal constriction to phenylephrine compared to subjects with four copies of HBA(p < 0.01).These results offer compelling new genetic evidence from humans supporting the role of alpha globin as a regulator of NO signaling in resistance arteries. We demonstrate that HBA deletions reduce arterial expression of HBA and change arterial vasoreactivity. This clinical investigation defines a novel vascular phenotype for individuals with alpha thalassemia and provides insight into a vascular mechanism by which alpha globin gene deletions protect against severe malaria, chronic kidney disease, and vascular complications of sickle cell disease.
Activation of Cold‐Sensitive Afferents Inhibits Aberrant Irritant‐evoked Cardiopulmonary Reflexes in the Spontaneously Hypertensive (SH) Rat
Authors: Hooper Justin S. , Taylor‐Clark Thomas 
Published: May 2022

Inhalation of irritants activates airway vagal afferent nerves, evoking cardiopulmonary reflexes. Evidence suggests that cardiopulmonary reflexes evoked by irritant/pollution inhalation are remodeled from bradycardia in normal subjects to tachycardia and ventricular arrhythmia in patients with pre‐existing cardiovascular disease. We have shown similar remodeling in the spontaneously hypertensive (SH) rat: selective activation of airway vagal afferent nerves via inhalation of the TRPA1‐specific agonist allyl isothiocyanate (AITC) evoked parasympathetic‐mediated reflex bradycardia in normotensive wistar‐kyoto rats but evoked sympathetically‐mediated tachycardia and premature ventricular contractions (PVCs) in spontaneously hypertensive (SH) rats.Activation of TRPA1‐expressing airway vagal afferents also evokes cough in some conscious animal models. Cough reflexes have been shown to be inhibited by nasal stimulation with L‐menthol via activation of TRPM8 ion channels expressed on cold‐sensitive trigeminal afferents which regulate brainstem respiratory networks. Here, we investigated the cardiopulmonary reflexes evoked by inhalation of L‐menthol (150mg/ml) alone and in combination with AITC (4.7mg/ml) in SH rats. L‐menthol inhalation alone had no effect on respiration/heart rate, but, when inhaled during AITC inhalation, L‐menthol selectively inhibited the AITC‐evoked tachyarrhythmia and tachypnea. Importantly, the inactive isomer D‐menthol (150mg/ml) failed to affect AITC‐evoked sympathoexcitatory reflexes. In another set of studies, the selective TRPM8 agonist WS‐12 (300mM) also inhibited the AITC‐evoked tachyarrhythmia. Therefore, we conclude that aberrant cardiopulmonary reflexes evoked by irritant inhalation are reduced by activation of menthol‐sensitive pathways within the airways. This data supports the therapeutic potential of menthol treatment against irritant‐evoked cardiopulmonary reflexes.
TRPM4 Ion Channels in Glycemic Control during Pregnancy
Authors: Wuyts Caroline , Philippaert Koenraad , Pinto Silvia , Simoens Caroline , Vennekens Rudi 
Published: May 2022

During pregnancy, the glucose homeostasis of the mother adapts to accommodate the needs of a growing fetus. Decreased insulin sensitivity and increased insulin secretion from the pancreatic beta‐cell contribute to this adaptation. Electrophysiological changes in the beta‐cell during pregnancy, that could explain the increased insulin secretion, have not yet been identified. The non‐selective Transient Receptor Potential Melastatin 4 (TRPM4) cation channel, expressed in beta‐cells, may depolarize the beta‐cell membrane and promote insulin release. In other organs, TRPM4 ion channel expression fluctuates depending on the relative concentration of estrogen and progesterone, hormones important during pregnancy. These findings suggest a role of TRPM4 in glycemic control, which can be influenced by female reproductive hormones during pregnancy.Using in vivo continuous glucose monitoring throughout the full pregnancy of wildtype (WT) and TRPM4 knockout (KO) mice allows to analyze glycemia during oral glucose tolerance tests (OGTTs) and spontaneous feeding behavior, and to determine glycemic variability. TRPM4 KOmice are hyperglycemic compared to WT mice, mainly before and during the first half of pregnancy. The mean glucose concentration was increased in TRPM4 KO mice in the beginning of pregnancy. In both WT mice and TRPM4 KO mice, the overall glycemia gradually increased during this period, maintaining the difference in glycemia between the two genotypes. Later in pregnancy, the glycemia of both genotypes started gradually decreasing. However, glycemia of TRPM4 KO mice decreased faster, reducing the difference in glycemia between the two genotypes. This indicates a different adaptation to pregnancy. The maximum glucose levels reached during the OGTTs were larger for the TRPM4 KO mice compared to the wildtype mice, which is in line with the general observed hyperglycemia of TRPM4 KOmice. Furthermore, we observed that fasting glucose concentrations, obtained right before the OGTTs, were significantly increased for the TRPM4 KO mice compared to WT mice. Glycemic variability provides information regarding sudden changes and fluctuations in the blood glucose concentration. In general, there were no substantial differences in terms of glycemic variability between both genotypes. To conclude, we could show that TRPM4 plays an active role in glycemic control, before and during pregnancy.
Effects of Dual‐Species Biofilm Formation on Plastic Degradation by Ideonella sakaiensis
Authors: Williams Tawnie B. , Russell Andrew R. , Mitchell Jon C. 
Published: May 2022

As of 2015, nearly 80% of the world’s virgin plastic ended up in a landfill or the natural environment, a majority accredited to the packaging industry. Due to the composition of the durable plastic, polyethylene terephthalate (PET), the primary polymer found in single‐use packaging, is not naturally biodegradable and thus accumulates. Recently, several microbes were discovered that could degrade the plastic compounds within their gut with no signs of toxicity. Ideonella sakaiensisis a novel bacterium capable of depolymerizing PET using a hydrolase termed PETase. An additional enzyme, MHETase, aids in converting dimers for the complete recovery of monomers within I. sakaiensis. Ultimately, efficiency in degrading PET of varying crystallinity occurs with a preference of low crystallinity PET, in opposition to other species currently known. During degradation, I. sakaiensisforms a thin biofilm over the plastic. It is known that the cells contain special appendages to adhere to the plastic surface, however, little research has been conducted on how the biofilm formation affects the degradation process. Multi‐species biofilms have been shown to create complex communities for enhanced PET degradation in marine plastic debris using other bacterial strains.This research aims to study the biofilm formation as well as its effects on its degradation properties of I. sakaiensisas an isolate, as well as a dual species biofilm with known biofilm forming bacteria: Stenotrophomonas maltophilia, Staphylococcus aureus, and Pseudomonas aeruginosa. The first half of the project characterized the effects of introducing biofilm forming bacteria on I. sakaiensis’ biofilm growth. The second half of the project analyzes the biofilm growth along with a degradation assay to determine the effects of these bacterial strains on the degradation process of I. sakaiensis. These effects were then evaluated to determine the role of biofilm formation in the degradation process. This study provides a foundation that can be used by the biotech, environmental, and molecular communities to lead to a commercialization of plastic degradation products, ultimately creating a circular and stable economy within the consumer world.
Characterization of Novel, Agmatine‐Based NMDA Receptor Antagonists in Multiple Pain States
Authors: Peterson Cristina , Kitto Kelley F. , Wilcox George L. , Fairbanks Carolyn 
Published: May 2022

The worsening opioid epidemic has highlighted the need for the development of new, safe, and effective analgesic therapeutics. Opioid therapy currently is associated with the risk of conversion to addiction, diversion from patients for whom use is intended, and the development of analgesic tolerance, or the loss of efficacy with continued treatment. To this end, we have developed a line of non‐opioid, agmatine‐based compounds and assessed them for their efficacy in reversing behavioral expressions of pain in animal models, as well as evaluated their safety following chronic exposure. We have previously shown that agmatine, decarboxylated L‐arginine, is an N‐methyl‐D‐aspartate (NMDA) receptor antagonist that preferentially antagonizes receptors that express NR2B subunits. This preferential antagonism is desirable for NMDA‐based therapeutics as it can lead to a widening of the therapeutic window and avoidance of the side effects commonly associated with NMDA antagonism including motor ataxia and psychoactive effects. However, agmatine has shown limited penetration through the blood brain barrier (BBB) and a short systemic half‐life, limiting its clinical utility. We have designed strategically‐substituted agmatine (SSA) compounds with the goal of improving its penetration through the BBB by increasing the lipophilicity of agmatine, potentially improving distribution across the BBB and increasing its half‐life following systemic delivery. To this end, we have evaluated this series of SSAs for safety and efficacy in multiple animal models of pain.Mice (21‐30 g, M/F) were assessed for their baseline mechanical sensitivity, and then one of several models of pain was induced: inflammatory pain (Complete Freund’s Adjuvant, (CFA) injected into a hindpaw), neuropathic pain (spared nerve injury surgery), or post‐surgical pain (hindpaw muscle incision). Mechanical sensitivity was again assessed, then an SSA compound, agmatine (the parent compound), or vehicle control was administered, and mechanical sensitivity was recorded for up to three hours following administration. The SSA compounds effectively reversed pain behaviors in mice following administration in the various pain models. Additionally, side effects characteristic of NMDA receptor antagonists were assessed and not found at the range of doses that produced analgesia, indicating a wide therapeutic window.These data indicate that the strategically‐substituted agmatines are anti‐hyperalgesic compounds with a wide therapeutic window, avoiding the motor impairment typical of drugs of this class.