bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards a pan‐group activator of the quorum sensing system in the common pathogen Staphylococcus epidermidis
Authors: Shen Wenqi , Tian Yang , Blackwell Helen E. 
Published: June 2021

Quorum sensing (QS) is a chemical communication process that allows bacteria to regulate gene expression based on changes in population density and environmental cues, thereby enabling bacteria to coordinate their behaviors on a community‐wide scale. Among pathogens, QS is often found to play an important role in virulence. One such pathogen is the Gram‐positive bacteria Staphylococcus epidermidis. S. epidermidis is a leading cause of hospital‐acquired infections, and these infections are difficult to eradicate via traditional antibiotic therapy due to increasing antibiotic resistance and the formation of robust biofilms. The pathogenesis of S. epidermidis is mainly under the control of the accessory gene regulator (agr) QS system. agr activation is achieved by the binding of the cyclic peptide (an autoinducing peptide or AIP) signal to its cognate receptor AgrC. Synthetic compounds that target the agr system could represent valuable tools to elucidate the roles of QS and the agr system during S. epidermidis infections.S. epidermidis can be classified into three specificity groups (I, II, or III) based on the unique AIP sequence used by each group (AIP‐I, ‐II, or ‐III). A previous study characterizing the AIP‐I signal has yielded synthetic group‐specific and pan‐group inhibitors targeting the S. epidermidis agr system. The development of pan‐group activators of the agr system is of significant interest, however, as agr activation can reduce biofilm formation by S. epidermidis. To date, no such activators have been identified. The present study was directed toward the identification of synthetic pan‐group agr activators in S. epidermidis by studying and delineating the structure‐activity relationships (SARs) of AIPs‐I, ‐II, and ‐III. Our preliminary data show that the residues at the exocyclic tail region of AIP‐II and AIP‐III are important to maintain the efficacy and potency of the native AIPs, as well as the residues that are important for receptor activation, causing a switch in certain cases from activator to inhibitor. We have also identified endocyclic residues that are important to receptor binding and activation, as well as residues that are more tolerant to change. Utilizing the findings from these systematic SARs studies for all three native AIPs, we designed a small set of AIP analogs containing features hypothesized to be important for receptor activation in each agr group, and tested these AIP analogs in all three groups using reporter strains. From this focused set of AIP analogs, we discovered the first set of pan‐group activators of S. epidermidis agr system. Current efforts are directed toward improving the potency and the efficacy of these compounds, and their application to reduce biofilm accumulation of S. epidermidis on abiotic surfaces.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
In Vitro Microbiological Evaluation Of Some Metal Complexes Of 4‐Hydroxy‐2‐Oxo‐2H‐Chromene‐3‐Carbonitrile
Authors: Odai Sevdije Govori , Ibrahimi Hamide , Daci Majlinda , Haziri Arben 
Published: June 2021

New complexes of 2‐Oxo‐2H‐Chromene‐3‐Carbonitrile with cobalt [Co (II)], nickel [Ni(II)], iron [Fe(III)] and chromium [Cr(III)] were synthesized. The structure of synthesized compounds were characterized by IR, 1H‐NMR and elemental analysis. The synthesized ligand and metal complexes were screened for microbiological activity against Escherichia coli Staphylococcus aureus, and Klebsiella pseumoniae. The complexes have enhanced activity compared to the 4‐Hydroxy‐2‐Oxo‐2H‐Chromene‐3‐Carbonitrile itself as ligand.Support or Funding InformationSupport for this study was provided by the Ministry for Education, Science and Technology of the Republic of Kosovo. Grant number:2‐5521‐2This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
International Research Infrastructures ‐ New research opportunities for biochemists and molecular biologists
Authors: Stechmann Bahne 
Published: June 2021

In Europe, biomedical research infrastructures joined forces in the CORBEL project (www.corbel.project.eu) to offer international scientists open‐access to a wide range of state‐of‐the‐art technology platforms, resources and services in the fields of chemical biology/drug discovery (www.eu‐openscreen.eu), medical and biological imaging (www.eurobioimaging.eu), structural biology (www.structuralbiology.eu), mouse models (www.infrafrontier.eu), clinical resarch (www.ecrin.org), databases (www.elixir‐europe.org), biobanks (www.bbmri‐eric.eu), microbiology (www.mirri.org), marine biology (www.embrc.eu), systems biology (http://project.isbe.eu) and translational research (https://eatris.eu).In the field of Chemical Biology, the academic initiative EU‐OPENSCREEN (www.eu‐openscreen.eu) integrates high‐capacity screening platforms and medicinal chemistry groups throughout Europe. Researchers from academic institutions, SMEs and industrial organisations from around the world can access the rationally selected EU‐OPENSCREEN compound collection, comprising up to 140.000 commercial and proprietary compounds collected from European chemists, to develop novel molecular tool compounds for the validation of novel biological targets, in collaboration with its partner screening platforms and medicinal chemistry groups. Molecular biologists and biochemists who have a robust and suitable assay and are interested in developing a chemical ‘tool’ compound (i.e. inhibitor or activator) for their target‐of‐interest are invited to contact us to discuss their research project. After the screening and identification of active hit compounds, researchers can collaborate with EU‐OPENSCREEN's medicinal chemistry groups during the hit‐to‐tool optimisation, use the imaging facilities of Euro‐BioImaging to characterise the biological effect of the identified compounds, or access INSTRUCT to gain structural information of the biological target.I will highlight these research infrastructures in more detail and explain how international biochemists and molecular biologists can access and collaborate with these research infrastructures to advance their research projects.Support or Funding InformationThis project (CORBEL) receives funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654248.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Protective Effects of a Red Maple (Acer rubrum) Leaves Extract on Human Keratinocytes against H2O2‐induced Oxidative Stress
Authors: Ma Hang , Guo Hao , Liu Chang , Wan Yinsheng , Seeram Navindra P. 
Published: June 2021

The red maple (Acer rubrum) species is endemic to eastern North America. It has been used as a folk medicine by the indigenous people of North America to treat dermatological ailments including skin irritation and inflammation. A series of glucitol‐core containing gallotannins (GCGs) has previously been identified from red maple aerial plant parts. Also, ginnalin A (GA), a major GCG in a proprietary phenolic‐enriched red maple leaves extract (Maplifa™), showed anti‐melanogenic effects in murine melanoma B16F10 cells by down‐regulation of tyrosinase and melanogenic gene expression as well as reduction of oxidative stress. However, the dermatological protective effects of Maplifa™ and GA on keratinocytes remain unknown. Herein, we report the protective effects of Maplifa™ and GA on hydrogen peroxide (H2O2)‐induced oxidative stress in human keratinocyte HaCaT cells. H2O2 (at 200 μM) induced cell damage of HaCaT cells and reduced cell viability by 14%. Maplifa™ (at concentrations ranging from 6.25–25 μg/mL) significantly reduced H2O2‐induced cytotoxicity in HaCaT cells and increased cell viability by 25–55%, respectively, as compared to the H2O2‐treatment group. Similarly, GA (at concentrations ranging from 6.25–50 μM) significantly increased cell viability by 34–47% respectively, as compared to the H2O2‐treatment group. In summary, Maplifa™ may have skin protective effects by reducing oxidative stress in keratinocyte HaCaT cells warranting further studies to evaluate its cosmetic applications.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Inhibition of pentameric ligand‐gated ion channels by lophotoxin, a diterpenoid from coral Lophogorgia chilensis
Authors: Camacho‐Hernandez Gisela Andrea , Huber Laura , Fenical William , Taylor Palmer 
Published: June 2021

Lophotoxin is a member of a cyclic diterpenoid family of toxins, devoid of nitrogen, that are isolated from the soft coral Lophogorgia. Previous work shows irreversible binding of lophotoxin to nicotinic acetylcholine receptors (nAChRs), utilizing membranes prepared from the electric organs of Torpedo californica; the inhibition is thought to be mediated by an electrophilic addition of the toxin with a hydroxyl of a conserved tyrosine (Tyr 190) of this family of receptors. According to molecular modeling, a carbon located in the epoxide moiety of the structure, may form a covalent bond that will irreversibly inhibit nAChRs. This unique family of toxins appear to bind to the agonist site of the nAChR, since binding can be prevented by reversible agonists, such as epibatidine, or competitive antagonists, such as MLA. To investigate receptor interactions of lophotoxin with neuronal nicotinic acetylcholine receptors (nAChRs) and related pentameric ligand‐gated ion channels, we employed HEK cells transfected with cDNA's encoding one of three receptor subtypes: α7‐nAChR, α4β2‐nAChR and 5HT3AR, along with a fluorescent reporter, and a receptor extracellular domain surrogate, the soluble, acetylcholine binding protein (AChBP).We found that lophotoxin not only inhibited α7‐nAChR, α4β2‐nAChR function and AChBP ligand binding, as expected, but surprisingly also function of the serotonin gated ion channel (5HT3A). Our results suggest that these diterpinoid toxins may function not only as self‐defense agents against predators attacking branching points of the coral exoskeleton, but may also inhibit proliferation and attachment of neighboring species that could be a threat for this coral, since serotonin activation has been related to induction of germinal vesicle breakdown in bivalves and spawning in coral species. The mechanism and molecular determinants of lophotoxin interactions with pentameric ligand‐gated ion channels are still unclear, but may be resolved through X‐ray crystallographic and mass spectrometry studies with the soluble receptor surrogate, AChBP.Support or Funding InformationCONACYT graduate fellowship to GACHThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Fenugreek Saponin Improves Insulin Sensitivity in Obese Subjects ‐ A Randomized, Placebo Controlled, Pilot Study
Authors: Nair Sreejayan , Barnes Scarlette L. , Smith Derek T. , Nair Anand S. 
Published: June 2021

BackgroundOur preclinical studies and non‐randomized clinical studies by others have demonstrated that fenugreek saponin has beneficial metabolic effects in diabetes.AimThe aim of this study was to evaluate whether intervention with fenugreek saponin alters body composition and cardiometabolic parameters in obese, insulin‐resistant subjects.Trial DesignThis was a prospective, double blind, placebo‐controlled, randomized, pilot clinical study.MethodsTwenty‐eight male or female subjects with body mass index >25 Kg/m2 and satisfied one of the following 3 criteria, HbA1c >5.6%, 2 h‐post‐challenge glucose > 25 mg/dL, homeostasis model of insulin resistance (HOMA‐IR) >2.5, were randomly assigned to receive either placebo or fenugreek saponin capsules (500mg, twice daily) for 12‐weeks. Body composition (anthropometric measurements, dual energy X‐ray absorptiometry, DEXA) and clinical chemistry (serum lipids, glucose, insulin and C‐reactive protein) and enzyme‐linked immunosorbent assays (for pro‐inflammatory cytokines (tumor‐necrosis factor‐alpha) and oxidative stress (isoprostanes) were performed before and at the end of the intervention. For each parameter the difference between the pre‐ and post‐treatment values were determined and the mean of the delta value was used to determine differences between the groups.ResultsThree months intervention with fenugreek saponin had no effect on body weight, whole‐body fat mass, lean mass and android to gynoid ratio as compared to placebo. Neither did treatment with fenugreek saponin alter fasting serum lipids, insulin, glucose or HbA1c. However, the mean HOMA‐IR was significantly attenuated in the subjects receiving fenugreek saponin. Furthermore, a significant reduction in serum TNF‐alpha and isoprostane levels were observed in the treatment group.ConclusionsFenugreek saponin reduces insulin resistance, inflammation and oxidative stress in obese, insulin resistant subjects. Whether these effects translate to improving glucose control needs to be evaluated in larger studies in diabetic subjects.Support or Funding InformationThis work was supported by a pilot project grant from CTR‐IN which is supported by the NIH through the National Institute of General Medical Sciences #1U54GM104944‐01A1 under the Institutional Development Award (IDeA) program.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Assessment of Humulus lupulus' essential oil profile and its effect on fungal infection
Authors: Walden Sean D. , Anderson C. William , Lowry Edward , Wolyniak Michael J. 
Published: June 2021

Humulus lupulus, commonly known as the common hop, is a lucrative cash crop grown in large quantities across Europe and the northwest region of the United States. The mature female flowers, or cones, of H. lupulus produce a yellow, sappy substance as a defense mechanism against insect herbivory. This substance, commonly known as lupulin, contains a collection of essential oils that have signature strong flavors and aromatic qualities that give hops their commercial value in brewing. Beer and mead, the products of hops‐mediated brewing, obtain their unique flavors through the different combinations of oils produced by different varieties of H. lupulus.While the anti‐herbivory properties of H. lupulus essential oils are well‐established, relatively less is known about their role in suppressing the growth of pathogenic fungi. Indeed, H. lupulus populations have been plagued by Downy Mildew (Pseudoperonospora humuli) and Powdery Mildew (Podosphaera macularis). These pathogens can infect entire commercial crops in a short amount of time and can cost commercial producers a significant amount of money if crops become significantly infected. Coincidentally, the climate which favors growth of P. humuli and P. macularis is also the climate in which H. lupulus grow best. This fact underscores the importance of better understanding how to control the growth of these fungi with respect to the future of H. lupulus agriculture. In a recent study, essential oils from thyme (Thymus vulgaris L.) have been shown to have anti‐fungal qualities (Zambonelli 1996). Thus, the essential oils produced by H. lupulus could similarly be effective in preventing infection by these pathogens.With the goal of better understanding the role of essential oils and their distinct profiles in the many varieties of H. lupulus, five common varieties were profiled using Gas Chromatography‐Mass Spectroscopy (GC‐MS). This technique provides a holistic look at the different oils produced in different varieties of H. lupulus. Preliminary work has suggested that the most prominent essential oils present in all tested varieties includes humulene, beta‐myrcene, beta‐caryophyllene, and lupulon. Beta‐caryophyllene is especially interesting in these results based on its previously determined role as an anti‐fungal agent. Humulene is also interesting due to it being an isomer of beta‐caryophyllene. There are some less abundant oils in the profiles that are unique to distinct varieties and which are currently being analyzed through a measure of zone of inhibition following inoculation with individual essential oils on impregnated disks exposed to fungal cultures on potato dextrose agar (PDA) medium.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Utilizing Design Principles of Electrochemical DNA Aptamer Biosensors in Multiple Optical Assay Methodologies
Authors: Bonham Andrew J. 
Published: June 2021

DNA aptamers, short oligonucleotides with high specificity and affinity for a variety of molecular targets, have been widely adopted as capture probes and detection elements for a variety of assay and biosensor applications. In particular, electrochemical DNA (E‐DNA) biosensors have been demonstrated for many applications, ranging from the detection of metal ions (e.g., uranium and mercury), to small molecules (e.g., doxorubicin and other antibiotics), and even to large proteins (e.g., botulinum toxin and transcription factors). E‐DNA biosensors essentially consist of an aptamer oligonucleotide region that is incorporated into a larger oligonucleotide scaffold, with an anchoring modification (typically a thiol) and a reporter modification (typically the dye and redox reporter methylene blue) covalently appended. Recent efforts in our lab have focused on taking insights from E‐DNA biosensor design and incorporation of aptamers into functional probes, and applying them to a variety of alternative, optical assays repurposing existing E‐DNA probes. One of these approaches is the demonstration of Raman spectroscopic detection through dye‐labeled DNA functionalized gold nanoparticle assemblies that dissociate in a dose‐dependent response to the presence of the target molecule. A second approach has been the creation of portable, do‐it‐yourself 3D‐printed total internal reflectance fluorescence based assays using dye‐labeled DNA arrays on acrylate microscope slides where fluorescence intensity, which can be captured on a smart phone, reflects target presence. A third approach has focused on the characterization of rapid lateral flow assay (“dipstick”) assays based on DNA functionalized gold nanoparticles and nitrocellulose arrays, where target presence is reflected in the intensity of a nanoparticle‐based color line. Ultimately, these projects illustrate the high transferability of DNA aptamer biosensor design parameters between different sensing modalities, offering insight into engineering successful biosensor designs.Support or Funding InformationThis work is supported by internal grant funding from the Metropolitan State University of Denver.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A novel suite of genetically encoded fluorescent biosensors for dynamic and sensitive enzyme activity measurements in vivo
Authors: Mehta Sohum , Mo Albert , Zhang Jinfan , Zhang Jin 
Published: June 2021

Fluorescent protein‐based biosensors have revolutionized biomedical science by enabling the direct, real‐time visualization of molecular processes with high spatial and temporal resolution in living cells. In particular, biosensors based on fluorescence resonance energy transfer (FRET) are among the most versatile and widely used probes for investigating the dynamic, spatiotemporal regulation of enzymatic activities in the native biological context. Yet the transformative potential of these genetically encoded molecular tools is constrained by their generally low dynamic ranges, which limits their sensitivity in more physiologically and clinically relevant settings (i.e., in vivo). We have developed and optimized a novel class of genetically encoded enzyme activity biosensors whose dynamic ranges exceed those of even the best‐performing FRET‐based activity reporters by several decades and are easily the highest ever reported for genetically encoded enzyme activity reporters. These high‐performance molecular tools permit the robust, sensitive detection of subtle activity changes in vivo and thus further expand the frontiers of “native biochemistry”.Support or Funding InformationThis work was supported by Brain Initiative Grant R01 MH111516 and by R35 CA197622, R01 DK073368, and R01 GM111665 (to J.Z.).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Lipidomics reveals physiological isotope effects during the enzymatic oxygenation of polyunsaturated fatty acids ex vivo.
Authors: Navratil Aaron R. , Shchepinov Mikhail S. , Dennis Edward A. 
Published: June 2021

Arachidonic acid (AA, 20:4) is an omega‐6 polyunsaturated fatty acid (PUFA) and the main precursor to the class of lipid mediators known as eicosanoids. The enzymes that catalyze the oxygenation of AA begin by abstracting hydrogen from one of three bis‐allylic carbons within 1,4‐cis, cis‐diene units. Replacing bis‐allylic hydrogen atoms with deuterium has been shown to strongly slow the rate of enzymatic oxygenation of linoleic acid by soybean lipoxygenase, resulting in a kinetic isotope effect (KIE). Yet, experimental determination of the KIE during oxygenation of AA by mammalian cyclooxygenase (COX) and lipoxygenase (LOX) has revealed far lower values. All prior studies investigating the KIE of PUFA oxygenation have relied on in vitro systems using purified enzymes and were limited by availability of deuterated PUFAs. Here we demonstrate the use of macrophages as an ex vivo model system to study the physiological kinetic isotope effect (PKIE) during enzymatic AA oxygenation by living cells using a newly synthesized library of deuterated AA isotopologues. By extending sensitive lipidomic UPLC‐MS/MS approaches to simultaneously quantify native and deuterated lipid products, we were able to measure the magnitude of the PKIE for COX and LOX oxygenation of AA by macrophages. This work provides the first demonstration that hydrogen(s) present at carbon 10 (C10) of AA play an important role in the catalysis of prostaglandin and thromboxane synthesis. Furthermore, we discovered that deuteration of C10 also promotes the formation of the resolving lipid mediator lipoxin B4 by activated macrophages, possibly by interfering with AA cyclization and shunting AA toward LOX metabolism under physiological conditions.Support or Funding InformationNIH RO1 GM20501‐41This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.