bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intraneuronal Acidification with Acetic Acid, an Ethanol Metabolite, Increases Excitability of Central Nucleus of Amygdala Neurons with Axon Projecting to Rostral Ventrolateral Medulla (CeA‐RVLM)
Authors: Chapp Andrew D. , Driscoll Kyle M , Shan Zhiying , Carter Jason R. , Chen Qing‐Hui 
Published: November 2023

We have reported that activation of central nucleus of amygdala (CeA) is involved in the in vivo sympathoexcitatory and pressor responses to acute local challenge of acetate, the ethanol metabolite. However, the underlying neural mechanisms have not been determined. Evidence indicates weak organic acids are capable of decreasing intracellular pH due to intracellular transport of the organic acid and alternating neuronal activity. Recently, we have found that bath application of acetate caused a dose dependent increase in the in vitro excitability of CeA neurons with axon projecting to rostral ventrolateral medulla (CeA‐RVLM), which may underlie the mechanisms of increased sympathetic outflow in response to acetate challenge. We hypothesized that intraneuronal acidification due to intracellular transport of acetic acid may be a contributing factor. The role of intraneuronal acidification with the ethanol metabolite acetic acid was investigated under brain slice preparation. Specifically, we compared the action potential firing rate, depolarizing input resistance (Rinput), and voltage threshold (Vt) for firing action potentials between control intracellular recording solution (pH = 7.35) and 7.5 mM acetic acid loaded intracellular recording solution (pH = 5.20). In current‐clamp recordings, graded current injections evoked graded increases in discharge frequency among neurons from both groups. Maximum discharge evoked by +250 pA current injection in the 7.5 mM acetic acid loaded (pH = 5.20) group was 31 ± 1 Hz (n=6), which was significantly greater (P < 0.05) than that of controls group (pH = 7.35, 19 ± 1 Hz, n=7). Intraneuronal acidification with 7.5 mM acetic acid significantly (p < 0.05) increased Rinput of CeA‐RVLM neurons (731 ± 64 MΩ) compared to control (531 ± 48 MΩ). Likewise, 7.5 mM acetic acid caused a significant (p < 0.05) hyperpolarizing shift in Vt (−49.28 ± 1.37 mV) compared to control neurons (−43.83 ± 1.76 mV). In cultured neurons incubated with a pH sensitive probe, increases in bath application of acetate (7.5 mM) significantly (p < 0.05) increased the corrected fluorescence intensity of the neurons compared to control, indicative of a decrease in intraneuronal pH. This data suggests that extracellular acetate leads to intraneuronal acidification via transport of acetic acid which has profound effects on CeA‐RVLM membrane properties that enhance neuronal excitability and may contribute to the mechanism underlying alcohol associated sympathetic activation and hypertension.Support or Funding Information11SDG7420029 (ZYS) and R15‐HL122952 (QHC)
Changes in the Firing Frequency of Medullary Respiratory Neurons of Juvenile Female Rats Exposed to Chronic Intermittent Hypoxia
Authors: Souza George Miguel P R , Amorim Mateus R , Moraes Davi JA , Machado Benedito H 
Published: November 2023

Juvenile female rats exposed to chronic intermittent hypoxia (CIH) presented a significant reduction in the time of inspiration and increase in sympathetic activity during this phase of respiratory cycle, characterizing changes in the respiratory‐sympathetic coupling. There is evidence that the firing frequency of the pre‐sympathetic neurons is modulated by the respiratory neurons activity. In this context, we hypothesized that: in CIH‐female rats, the enhanced sympathetic activity during inspiration is due to the increased inspiratory neurons activity that modulates the pre‐sympathetic neurons firing frequency. We aimed to evaluate the respiratory neurons activity in the ventral surface of the medulla in juvenile female rats exposed to CIH. For this purpose, juvenile female rats (P20–21) were exposed to CIH (FiO2=6%) for 10 days and after this protocol we performed extracellular single unit recordings of medullary respiratory neurons using the working heart‐brainstem preparation (ventral approach). The respiratory neurons were identified and classified by their activity (firing frequency) in relation to the phrenic nerve activity. All experimental protocols were approved by the institutional ethical committee (#091/2013). Pre‐inspiratory/Inspiratory (Pre‐I/I) neurons of CIH‐female rats (n=12) presented a reduced firing frequency (39.3 ±5 vs 61.5 ±8 Hz, p=0.027) when compared to control (n=10). Ramp‐I, Post‐I and Aug‐E neurons presented no significant changes in their firing frequency in CIH‐female rats compared to control. We concluded that Pre‐I/I neurons presented a reduced firing frequency in CIH‐female rats, which may explain the reduced time of inspiration.Support or Funding InformationFAPESP, CAPES and CNPq.
Decreases in Core Temperature and Sweating Onset During Whole‐body Heating in Individuals with Multiple Sclerosis Following Administration of 4‐aminopyridine
Authors: Huang Mu , Allen Dusty R , Frohman Elliot M , Davis Scott L 
Published: November 2023

Multiple sclerosis (MS) is a progressive neurological disease of the central nervous system that can result in impairments in thermoregulatory function. 4‐aminopyridine (4AP), a voltage‐gated K+ channel blocker, has been postulated to improve conduction in demyelinated axons and improve MS related disabilities. The aim of this study was to test the hypothesis that administration of 4AP would improve sudomotor function in individuals with MS during passive whole‐body heating (WBH). Eleven subjects (8 females, 3 males; 39±7 years; 78.6±24.0 kg; 170±9 cm; 8±4 years since diagnosis) with relapsing‐remitting MS participated in this study. A randomized single‐blinded 2‐week crossover design was utilized with 4‐AP and placebo (PBO) including a 1‐week washout period between drugs. Subjects were outfitted in a tube‐lined water perfusion suit and exposed to a normothermic (NT) baseline (34 °C water) and WBH (48 °C water; increase in internal temperature of ~0.8 °C) condition. Core body temperature (telemetric pill) and sweat rate at the dorsal forearm (capacitance hygrometry) were continuously measured. Baseline NT core body temperature while on 4AP was lower compared to placebo (4AP: 37.3±0.2 °C vs. PBO: 37.5±0.2 °C, p=0.002). Core body temperature at the onset of sweat was also lower while on 4AP compared to placebo (4AP: 37.4±0.2 °C vs. PBO: 37.6±0.3 °C, p=0.0006). However, sweat rate (Δ from NT) on 4AP was similar compared to placebo during WBH (4AP: 0.7±0.3 mg/cm2/min vs. PBO: 0.8±0.4 mg/cm2/min, p=0.49). These initial findings suggest K+ channel blockers may have protective benefits for people living with MS by lowering resting core temperature and the sweat onset core temperature threshold. Thus, administration of 4AP may improve heat sensitivity in MS by expanding the range for core temperatures increases prior to symptom worsening.Support or Funding InformationProject funded by NIH grant (R15 HL117224) and National Multiple Sclerosis Society grants (RG4043A, RG4696A, PP1485)
A monofunctional nonribosomal peptide synthase might be involved in the biosynthesis of marine toxins of the palytoxin family
Authors: Yamazaki Tomoko 
Published: November 2023

The aim of this study was to identify in the transcriptome of the dinoflagellate Ostreopsis ovata genes, particularly such encoding nonribosomal peptide synthases (NRPSs), that are possibly involved in the biosynthesis of ovatoxins. Polyketide synthases (PKSs) and NRPSs are multienzyme complexes of mainly bacterial and fungal secondary metabolism. They comprise various enzymatic activities and are often organised in so‐called modules, each of which inserts one building block. The minimal NRPS module consists of an adenylation domain (A domain), which selects and activates the substrate, a condensation domain (C domain), which catalyses the formation of the new peptide bond, and a thiolation domain for binding intermediates. In the last decade, PKS and NRPS genes have also been identified in various protists, including some dinoflagellate species. A strain of the dinoflagellate O. ovata that was sampled in Okinawa, Japan, produces several ovatoxin variants. Ovatoxins belong to the same structural family as the extremely poisonous compound palytoxin. The biosynthetic scheme of palytoxin and its congeners is completely unknown. Sequencing of the O. ovata transcriptome by means of RNA‐Seq revealed a wide range of genes encoding PKSs and NRPSs. Most interestingly, O. ovata possesses a new type of NRPS, which is characterised by an unusual monofunctional architecture. This monofunctional architecture resembles a special type of monofunctional PKSs that have been found exclusively in dinoflagellates. The same type of monofunctional NRPSs found in O. ovata was also identified by screening the published draft genome of the dinoflagellate Symbiodinium minutum. These enzymes form a distinct dinoflagellate‐specific clade in comprehensive phylogenetic reconstructions including NRPSs from bacteria, fungi and other eukaryotes. Expression of those genes on the RNA level was confirmed by RT‐PCR, and the sequences of the transcripts demonstrated that the transcriptome‐based prediction of monofunctional NRPSs was not an artefact caused by assembly issues. Therefore, this study has experimentally demonstrated for the first time the existence of a new type of NRPSs, which at present seems to be limited to dinoflagellates. Structural modelling revealed differences between the active centre of A domains of dinoflagellate origin and those from bacteria and fungi. This new type of NRPS found in O. ovata might be involved in the biosynthesis of ovatoxin and related compounds, as the ovatoxin structure hints to incorporation of an amino acid as part of the biosynthesis pathway. The finding presented here will make it possible to initiate the elucidation of the biosynthesis scheme of palytoxin and related compounds.Support or Funding InformationThis study was supported by internal funds of the Okinawa Institute of Science and Technology Graduate University (OIST).
COnsortium for METabolomics Studies (COMETS): Leveraging Resources to Accelerate Scientific Discovery
Authors: Albanes Demetrius , Moore Steven , Ulrich Cornelia , Stolzenberg‐Solomon Rachael , Poole Elizabeth , Temprosa Marinella , Verma Mukesh , Boerwinkle Eric , Casas Juan , Clish Clary , Gerszten Robert , Gunter Marc , Harris Tamara , Herrington David , Langenberg Claudia , Le Marchand Loic , Lotta Luca , Matthews Charles , Menni Cristina , O'Donnell Christopher , Pereira Alexandre , Rexrode Kathryn , Shah Svati , Shu Xiao Ou , Stevens Victoria , Yu Bing , Zanetti Krista 
Published: November 2023

Metabolomics is a systems approachto the biology of health and disease and an ‘‐omics’ discipline that measuressmall metabolites representing end products of a variety of metabolic andcellular processes as reflected in available biological specimens (e.g., blood,urine, saliva, feces and tissue). As an emerging approach used forepidemiologic and clinical studies, metabolomics has the potential to improvedisease risk assessment, screening, diagnosis, prognosis and predictiveresponse to therapy, as well as provide disease mechanistic insight and help toestablish criteria for causation. The number of publications of epidemiologicalstudies that use metabolomics technology has rapidly increased over the past 10years, including application to a wide variety of exposures and disease states.It is timely to establish mechanisms for leveraging existing resources and data for novel biomarker discovery using metabolomics approaches. To this end, the National Institutes of Health COnsortium of METabolomics Studies (COMETS) was established in 2014 (http://epi.grants.cancer.gov/comets/),and currently includes 25 prospective cohorts and 3 established consortia from the United States, Europe, South America, and Asia. The COMETS mission is topromote collaborations among prospective cohort studies that follow participants for a range of outcomes and perform metabolomic profiling of individuals. COMETS aims to facilitate an open exchange of ideas, knowledge, and results to accelerate a shared goal of identifying metabolomic profiles associated with chronic disease phenotypes (e.g., heart disease, diabetes, cancer). Here we describe the COMETS structure and activities which aim to advance the use and impact of metabolite profiling in population‐based research.Support or Funding InformationConsortium support: Intramural and Extramural Research Programs of the National Institutes of Health along with other individual cohort funding.
DNA Aptamers Blocking Activity of Anthrax Lethal Toxin
Authors: Ryabko Alena K , Kozyr Arina V , Kolesnikov Alexander V , Marin Maxim A , Zeninskaya Natalia A , Lisitskaya Lidia A , Shemyakin Igor G 
Published: November 2023

BackgroundAnthrax has been recently pinpointed as „deliberately emerging disease”. Apart from natural outbreaks occurring constantly around the world, lethality of anthrax and high resistance of B. anthracis spores to envioronment and disinfectants made it the most feared bioterrorist threat.Anthrax three‐component binary toxin consists of receptor subunit, known as protective antigen (PA), and two effectors, edema factor (EF), and lethal factor (LF). The PA‐LF complex known as lethal toxin (LeTx), causes macrophage death and, ultimately, fatal organ dysfunction. Until recently, no effective remedy existed to protect organism from LeTx action.Therapeutic antibodies (mAbs) neutralizing LeTx have been developed, however, all clinically approved mAbs are specific to PA with activity limited to the extracellular milieu, whereas LeTx already entered the cell is impune to the antibody‐mediated neutralization.Diagnostic and therapeutic potential of DNA aptamers, a new prospective class of affinity molecular tools, is actively explored in different fields, including pathogen detection and neutralization.ObjectiveThe purpose of the present study was to develop LeTx‐specific DNA aptamers capable to neutralize anthrax lethal toxin inside the mammalian cell.ResultsWe identified DNA aptamers binding LF by employing new technique tailored to avoid carryover of target‐specific DNA molecules with aptamers binding to the solid phase. For this purpose recombinant LF was produced as fusion protein with His6 affinity tag and cleavable SUMO peptide.Random oligonucleotide library (1014) was subjected to 6 rounds of panning and proteolytic separation of LF with bound aptamers from His6‐ SUMO peptide attached to IMAC magnetic beads. Selected aptamers were analyzed for capability to block proteolysis of internally quenched fluorescent LF substrate. Positively acting aptamers were tested for blocking LeTx intoxication in mice. Co‐administration of some selected aptamer species and LeTx to mice substantially increased their survival compared to the control groups injected with LeTx alone.ConclusionThe data obtained outlines DNA aptamers as prospective tools for the development of the new generation of therapeutic agents, combatting anthrax.Support or Funding InformationThe work was supported by Russian Science Foundation research grant No 14‐15‐00630.
Rational design of potent histidine kinase inhibitors with antimicrobial activities
Authors: Zschiedrich Christopher , Boibessot Thibaut , Lebeau Alexandre , Bénimélis David , Benfodda Zohra , Meffre Patrick , Szurmant Hendrik 
Published: November 2023

The excess use of antibiotics has resulted in the appearance of multidrug resistant pathogens, described as one of the most eminent threats to human health in the 21st century. To address this problem many unique fundamental processes for bacteria are being probed for the development of new antimicrobial drugs. In bacteria signaling via the two‐component system is a widespread mechanism, with bacteria typically featuring in excess of 10 such systems per genome. The two‐component system consists of a sensor histidine kinase and a response regulator. A conserved two‐component system (YycFG aka WalRK) essential for viability has been discovered in most gram‐positive pathogens suggesting that inhibition of these systems would lead to cell death. However, targeting a single system can be expected to quickly result in drug resistances. It would thus seem desirable to discover compounds with the ability to inhibit multiple two‐component systems simultaneously. Synthetic compounds have been described as potent competitive inhibitors of DNA gyrase and one such compound has entered phase 1 clinical trials. Gyrases share a common catalytic ATP‐binding domain with histidine kinases; redesign of these compounds to bind the catalytic domain of the latter thus seemed possible. We utilized available high‐resolution structures of the inhibitor/gyrase complex and of a histidine kinase catalytic domain to rationally design novel compounds and probe histidine kinase binding in silico. The most promising in silico hits were synthesized and tested for their ability to inhibit several histidine kinases of Bacillus subtilis. A series compounds were found to be potent inhibitors of all tested histidine kinases but did not inhibit the structuraly distinct ser/thr kinases in vitro. Several of these compounds showed antimicrobial activities against methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococcus faecalis (VRE) and other Gram‐positive pathogens. Hemolytic assays on sheep erythrocytes ruled out that these compounds act by simply lysing cells, a problem encountered with many previously discovered histidine kinase inhibitors. In summary, the discovered compounds are promising leads for the development of new antibacterial drugs.Support or Funding InformationThis work was supported by grant GM106085 from the US National Institute of General Medical Sciences, National Institutes of Health
Immune modulator effects of hydroalcoholic extract of Matricaria chamomilla in mouse macrophages
Authors: Torres‐Tirado David , Leon‐Buitimea Angel , Perez‐Flores Gabriela 
Published: November 2023

In México is common the use of medicinal plants to treat different illness and symptoms. One of the most commonly used plant used is Matricaria chamomilla or chamomille which is a traditional plant with digestive activity and others effects test partially as antinflammatory and anesthetic that need to continue being studied. The presence of polyphenols in the hydroalcoholic extract suggests the ability to block signal transduction pathways like Mitogen Activated Protein Kinases (MAPK), this could have an important implication in the activation of the immune cells such as macrophages also strengthen the ability to react to external agents to organism. In this work we tested the effects of exposure to one hour of the chamomille hidroalcoholic extract in the J774 cell line and its effects in the viability, bacterial phagocytosis and the pathway activation of MAPK, ERK 1/2‐P. Preliminary results show that the viability of macrophages did not affected in one hour but decrease at the 6 hours of the expose, the phagocytosis of bacteria increase slightly to 5 % and ERK 1/2 expression has not change expression but phosphorylation of ERK 1/2 decrease importantly. Our preliminary conclusions are that the chamomile extract induce sensibility in phagocytosis to bacteria without affect its the viability but decreasing the MAPK pathway activation.Support or Funding InformationPROMEP UASLP‐DSA/103.5/14/11016 and FAI‐UASLP
Identification and testing of inhibitors of kinases secreted from malaria parasites
Authors: Lin Benjamin , Xu Lingyin , Winston Dennis , Brandt Gabriel 
Published: November 2023

Small molecule inhibitors of a family of secreted kinases from the malaria parasite Plasmodium falciparum were identified and shown to arrest parasite growth in blood culture. P. falciparum is primarily an intracellular parasite in its human host. During the blood stage of a malaria infection, the parasite dramatically alters the surface of its host red blood cell, by exporting proteins (accounting for roughly 10% of its genome) into the erythrocyte. Among these proteins is a family of 18 secreted Ser/Thr kinases. Recombinant expression of a number of these kinases and their Plasmodium vivax ortholog has permitted the screening of a library of potential kinase inhibitors. Several of these compounds were found to attenuate kinase activity in vitro. In order to ascertain whether inhibiting kinase activity affects the ability of parasites to remodel the red blood cell surface, the five best inhibitors were incubated with parasites in human blood culture. Scanning electron microscopy was used to assess the extent of red blood cell surface remodeling. Rather than an overt effect on remodeling, initial results showed an overall growth arrest of treated parasites, with no progression to trophozoites in the treated cultures.Support or Funding InformationAmerican Philosophical Society Franklin Research Grant
Effect of Altered Membranous Architecture in Vascular Smooth Muscle Contractility
Authors: Kuo Kuo‐Hsing 
Published: November 2023

Vascular smooth muscle is the direct effector on contractility of blood vessels and is pivotal in maintaining hemodynamic stability. In response to agonist stimulations, such as neurotransmitters, hormones or drugs, the smooth muscle cell (SMC) contracts in close correspondence to the local fluctuations of intracellular calcium ions (Ca2+), which is accomplished by a sequence of repetitive Ca2+ cycling events till the agonist is removed. In brief, the Ca2+ cycles are initiated by receptors binding on the plasma membrane (PM) and followed by: (1) Ca2+ release from the sarcoplasmic reticulum (SR) to activate the contractile machinery, (2) Ca2+ entering through the PM to refill SR Ca2+ storage and (3) Ca2+ removal from the cytosol, all underly the mechanisms of local and wave‐like Ca2+ transient signals. The membranous microarchitecture and microdomain, flanked by the PM and peripheral SR, are the gates to Ca2+ entry/removal and regulate Ca2+ signals. Altered PM may compromise the encoding of the Ca2+ signal and further affect SMC contractility. The objective of this study is to investigate the functional role of the membranous microarchitecture, the caveolar domain in specific, during adrenergic stimulation.The denuded venous vascular smooth muscle was incubated with the cholesterol depleting agent, methyl‐B‐cyclodextrin (MCD), to disrupt the caveolar domain to assess the impact of the altered PM on phenylephrine (PE)‐induced contractility. We observed enhanced sensitivity to PE and a right shift of the dose‐response curve for force generation in the MCD‐treated SMC. Ultrastructurally, the MCD‐treated SMC were characterized by a wavy PM, lack of caveolar domains and enlarged peripheral SR. Notably, the frequency of the wave‐like transient Ca2+ was also enhanced by a dose‐dependent feature to PE concentrations. We believe that the intensified frequency of the wave‐like Ca2+ signal underlies the enhanced PE sensitivity in MCD‐treated SMC and disrupted caveolar domains may delay Ca2+ removal and augment SR Ca2+ retention, contributing to the intensified frequency of the Ca2+ signals.Support or Funding InformationThe Discovery Grant by The Natural Sciences and Engineering Research Council of Canada (NSERC)