bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigations of Essential Oils as Quorum Sensing Inhibitors of Vibrio fischeri
Authors: Hinspeter Kallie , Danowitz Amy M. 
Published: June 2021

The misuse of traditional antibiotics has gradually caused a decrease in their efficacy. As bacterial resistance continues to spread, the need for the development of novel methodologies to prevent bacterial development has increased. One area of focus in this field is the inhibition of quorum sensing, a process by which bacteria are able to communicate and collectively regulate gene expression in a cell‐population density dependent manner through small molecules called autoinducers. By blocking cellular receptors which bind autoinducers, bacterial communication can be impeded. This can cause a decrease in community behavior including biofilm formation, production of virulence factors, and bioluminescence. Unlike traditional antibiotics, inhibiting quorum sensing obstructs virulence without preventing bacterial growth and is therefore thought to reduce the evolutionary drive for resistance development. Natural plant products, such as phytochemicals including phenolics, flavonoids, quinones, and alkaloids, have been shown to inhibit virulence factor production, quorum sensing, and microbial growth. This research initially aimed to examine the quorum sensing inhibition properties of select essential oils on Vibrio fischeri, a bioluminescent bacteria, through photometric assays. As the bioluminescent properties of Vibrio fischeri function through a quorum‐dependent pathway, the examination of this species allows for the easy detection of quorum sensing inhibition through the quantification of light production. Essential oils tested include caraway (Carum and Carvi oils), cistus or labdanum (Cistus ladaniferus), elemi (Canarium luzonicum), fir needle (Abies sibirica), and pine (Pinus sylvestris). Ongoing experimental results suggest that the essential oils originally selected for this research display antibacterial properties over quorum sensing inhibition. Due to this, future directions will likely move towards an examination of the antibiotic properties of these oils in Escherichia coli, a very common Gram‐negative pathogen that can be harmless in certain strains.Support or Funding InformationFunding for this project was provided by Mercyhurst University.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Accessing new chemical diversity from ancient non‐actinobacterial strains
Authors: Terrell Stephanie M. , Wu Yang , Klein Joshua G. , Charkoudian Louise K. 
Published: June 2021

Our work focuses on the discovery of new biosynthetic routes to chemical diversity through the characterization of unexplored polyketide synthase (PKS) gene clusters and enzymes from ancient and diverse phyla. In the first part of this work, two ancient non‐actinobacterial organisms were cultured, and their secondary metabolites extracted, fractionated, and characterized by liquid chromatography mass spectrometry (LC‐MS) in the search for novel molecules and biosynthetic pathways. These data are currently being compared to existing molecular networks in order to identify novel molecules. In a second part of this work, ancient non‐actinobacterial strains are being evaluated as a source of PKS enzymes that can be expressed in tractable heterologous hosts to enable in vitrocharacterization of poorly‐understood PKSs. We have successfully expressed a ketosynthase‐chain length factor (KS‐CLF) heterodimer pair, which is essential in the manufacturing of polyaromatic polyketides, in Escherichia coli, and are currently evaluating its activity in vitro. Results from these studies are expected to lead to the identification of new chemical diversity encoded by nature, as well as novel tools to enable the biosynthetic engineering of hybrid PKSs.Support or Funding InformationWe would like to acknowledge an NSF CAREER Award #R15GM120704 to Louise K. Charkoudian as a source of funding for this project.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cell‐Based Screening Platforms for Identification of Modifiers of Odor‐Triggered Mosquito Behaviors Acting through Binding to the ORco Subunit of Odorant Receptor Heteromers
Authors: Iatrou Kostas , Tsitoura Panagiota , Sdralia Nadia , Konstantopoulou Maria 
Published: June 2021

Insect olfactory receptors (ORs) are heteromeric ion channels consisting of a common subunit, ORco, and one of many variable subunits, ORx, to which odorants, receptor agonists or antagonists, bind in an ORx‐specific manner. In cells expressing the ORco subunit alone, however, ORco may also form a functional channel that is activated by ORco‐specific agonists. We have previously shown that mosquito repellents that block odor‐specific responses of multiple ORs of Anopheles gambiae mosquitoes, act as ORco antagonists that are capable of suppressing its activation by ORco‐specific agonists. We have also shown that the in vitro responses of heteromeric receptors that are induced by ORx‐specific agonists are enhanced by one to two orders of magnitude in the presence of either of two ORco‐specific agonists, VUAA1 and OrcoRAM2. The latter finding suggests the induction of allosteric changes in ORx‐bound heteromeric receptor complexes, which are caused by the binding of the ORco agonist and result in enhanced ion influx into the receptor‐expressing cells. To expand on these findings, we have designed a lepidopteran insect cell‐based expression platform that allows the fast screening of collections of pure compounds and compound mixtures for the presence of A. gambiae ORco agonists and antagonists in a single screening assay. Because mosquitoes should be able to detect the presence of olfaction‐relevant bioactive molecules in their natural environments, we screened for the presence of relevant compounds in (i) collections of essential oils obtained from aromatic plants and fractions thereof, which contain volatile constituents, and (ii) collections of pure volatiles of plant or bacterial origin. The initial screening effort resulted in the identification of a small number of hits acting as ORco‐specific agonists or antagonists from both types of examined collections. These hits are currently examined further to establish their functional relevance and effectiveness against mosquito populations in vivo. Should this testing prove the validity of the hypothesis that newly‐identified volatile ORco ligands may modify olfaction‐based mosquito behaviors in a predicted fashion, additional capacities will be generated for enhanced personal protection against indoor and outdoor transmission of malaria and other mosquito‐borne infectious diseases. We also note that equivalent screening platforms could be designed for identification of behavior modifiers of the same type for other arthropod species of interest.Support or Funding InformationThis work has been supported by the ENAROMaTIC consortium project (grant No FP7‐222927 of the EC) and was carried out in the facilities of the OPENSCREEN‐GR National (Greece) Research Infrastructure.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Development of ligand‐based inhibitors for protein N‐terminal methyltransferase
Authors: Huang Rong 
Published: June 2021

Protein alpha‐N‐terminal methyltransferases (NTMTs) are emerging members of protein methyltransferases and methylate the alpha‐N‐terminal amine of proteins starting with an X‐P‐K/R motif. Since its discovery in 2010, NTMT1 has been implicated in regulating chromatin interactions, mitotic division and DNA damage repair. Therefore, specific NTMT1 inhibitors are important tools to elucidate its biological and pharmacological functions. Our lab has developed the first mechanism‐based inhibitors by covalently connecting both substrates to mimic its ternary complex. However, there is no specific and cell‐potent inhibitor available for NTMT1 until now. Based on our crystal structures of NTMT1 ternary complexes, we identified the unique specificity of NTMT1 substrate binding pocket which is in contract to other protein methyltransferases. Thus, we applied a ligand‐based approach to rationally design peptidomimetic inhibitors and optimized in aid of NTMT1 structural information. Our top synthesized inhibitor has a Ki of 440 nM and its inhibition is through specific targeting the protein substrate binding site instead of the SAM binding site. Moreover, the inhibitor exhibits more than 100‐fold selectivity to NTMTs over nearly 40 other methyltransferases. In summary, we have successfully developed the first potent and specific peptidomimetic inhibitors. Our studies have laid a paradigm for the next optimization towards developing cell‐potent inhibitors to interrogate the biological roles of NTMTs.Support or Funding InformationNIH R01 GM117275This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Urinary Platelet‐Activating Factor as an Indicator of Interstitial Cystitis/Bladder Pain Syndrome
Authors: McHowat Jane , Isbell T Scott , Campian E Cristian 
Published: June 2021

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory bladder disease with multiple etiological contributors and risk factors associated with its development, including cigarette smoking. In a recently published manuscript, we have shown that smoking is associated with bladder wall inflammation and accumulation of platelet activating factor (PAF), a potent inflammatory mediator that facilitates transendothelial inflammatory cell migration and reduction in tight junction protein expression, which could contribute to urothelial cell dysfunction. PAF accumulation in response to cigarette smoking is primarily the result of the inhibition of PAF acetylhydrolase (PAF‐AH, the enzyme responsible for PAF hydrolysis and inactivation). The present study was designed to determine whether urine content of PAF or PAF‐AH activity can be used as an indicator of IC/BPS. For stability studies, voided urine specimens were collected from patients with and without a diagnosis of IC/BPS. Samples were stored at room temperature and frozen in liquid nitrogen at intervals up to 60 mins following voiding. PAF content and PAF‐AH activity were measured and normalized to creatinine. Measurement of PAF and PAF‐AH was consistent at all time intervals up to 60 mins, demonstrating stability following voiding. Addition of PAF internal standard to urine samples prior to analysis indicated a recovery of >96% PAF. PAF content in the urine of IC/BPS patients (1.16 ± 0.16 PAF:creatinine ratio, n=6, p<0.05) was significantly greater than that for non‐IC/BPS patients (0.37 ± 0.18 PAF:creatinine ratio, n=5). PAF content was also greater in IC/BPS patients who smoke (1.19 + 0.36 PAF:creatinine ratio, n=4, p<0.05) when compared to non‐IC/BPS patients. PAF‐AH activity was decreased in the urine of IC/BPS patients who were smokers (48.3 ± 2.4 PAF‐AH: creatinine ratio, n=4, p<0.05) or non‐smokers (40.0 ± 7.0 PAF‐AH: creatinine ratio, n=6, p<0.05) when compared to non‐smokers with no IC/BPS (64.6 ± 2.2 PAF‐AH:creatinine ratio, n=5). Our data demonstrate that urine content of PAF and/or PAF‐AH is stable at up to 60 mins storage at room temperature following voiding. Urinary PAF is increased in IC/BPS patients, and is likely the result of PAF‐AH inhibition. Future studies are required to determine the effect of cigarette smoking on the incidence and severity of IC/BPS.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Characterizing Binding Interactions and Elucidating Structure of Aptamer‐Based Biosensors
Authors: Armstrong Lindsay Therese , Bonham Andrew J. 
Published: June 2021

Electrochemical biosensors based on the conformational dynamics of DNA aptamers have found success against a wide variety of proteins, toxins, antibodies, and heavy metals. However, the mechanistic underpinnings of the mechanism by which these surface‐bound DNA molecules change conformation upon target binding, thus changing the dynamics of an appended redox‐active tag and generating a measurable signal, is poorly understood. Our first target for investigation was a previously reported Ricin Chain A binding aptamer biosensor. Here, we have investigated this biosensor using a variety of nucleic acid assays, including PCR‐termination via basepair modification, fluorescence anisotropy, gel mobility shift assays, and FRET tagging to determine 3D orientation. These have allowed us to better characterize the basepair interactions involved in binding targets, as well as offer clues to the changing three dimensional folded structures of these biosensors. These results will help inform the field of biosensors and aptamers in general on strategies for future optimization.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.
Development of Novel Biosensors for Non‐Invasive and Rapid Diagnosis of Celiac Disease
Authors: Nguyen Anna , Bonham Andrew J. 
Published: June 2021

There is a pressing need for rapid, non‐invasive, and accurate detection methods to diagnose individuals with the autoimmune disorder celiac disease (CD). It is estimated to affect up to two million Americans, and is caused by an autoimmune response to consuming gluten, resulting in damage to the lining of the gastrointestinal tract that leads to abdominal pain, diarrhea, nausea, and many other complications. Accurate diagnosis of CD remains challenging; the current diagnostic procedure involves multi‐day laboratory protocols, followed by an invasive duodenal biopsy. Here, we demonstrate work towards a blood sample‐based diagnostic tool to allow for early identification of CD in patients. Our method utilizes known autoimmune interactions that occur in the body of an individual with CD; specifically, when they consume gluten, a part of the gluten incorrectly binds to an enzyme in the bloodstream, and the resultant structure that forms between the gluten and the enzyme is targeted by their immune system. Researchers have identified how parts of this novel structure specifically interacts with the autoantibodies involved in CD. These peptide epitopes closely recapitulate the disease state. We have thus created a biosensor that relies on using these peptide epitopes as the capture probe to detect levels of disease‐specific antibodies. This strategy was incorporated into an electrochemical DNA (E‐DNA) biosensor; a common type of biosensor that utilizes small changes in electrical conductivity to measure whether a target molecule is bound or unbound. This sensor design can, in principle, use unprocessed finger‐lancet blood samples to provide a rapid digital readout, allowing for efficient and sensitive detection of CD in patients.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.
Comparative lipidomic profiling of parasite‐infected and non‐infected Northern saw‐whet owls.
Authors: Peros Colin S. , Garrett Teresa A. 
Published: June 2021

Haematozoa are present in avian species around the world. In some cases, parasite infection may be fatal. For example, Plasmodium and Leucocytozoon cause avian malaria and anemia, respectively, which can be detrimental to host species. These parasites are responsible for massive reductions in the populations of birds native to Hawaii, the Galapagos, and other archipelagos. However, the same parasites have seemingly benign effects in other avian species. Here, we use liquid chromatography‐mass spectrometry to analyze lipid profiles and study host‐parasite interactions in a population of Northern saw‐whet owls (Aegolius acadicus) known to be infected with Leucocytozoon (49.5%), Plasmodium (10%), Haemoproteus (5%), and Trypanosoma (2.9%). Fragment ions from MS/MS analyses revealed major classes of glycerophospholipids, including phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidylcholine (PC). Comparison of the total lipid profiles of infected and non‐infected owls revealed distinct features (p < 0.001) between the two groups in the negative‐ (30) and positive‐ion (376) mode. The lower levels (>1.7‐fold difference) of PC in infected individuals suggests haematozoa infections may influence lipid production, which may impact the health of birds. Further investigations can advance our understanding of bird physiology and the role lipid biomarkers may play in the conservation of parasite‐susceptible avian species.Support or Funding InformationSupported by National Science Foundation Major Research Instrumentation Grant #1039659.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
P‐cadherin Overexpression Enhances Survival Signaling in Dysplastic Oral Epithelia via the Epidermal Growth Factor Receptor
Authors: Neal Christine , Mody Aaron , Parker Ashley , Cameron Emily , Plager Susan , Lawson Kathryn 
Published: June 2021

P‐cadherin is a calcium‐dependent transmembrane protein that mediates cell‐cell adhesion within oral epithelial tissue. Previous histological analyses have suggested that P‐cadherin protein levels increase in oral dysplasia and subsequently decrease in oral squamous cell carcinoma (OSCC). The epidermal growth factor receptor (EGFR) gene has also been shown to undergo amplification in the dysplastic stage of oral tumor development. In comparative studies, we found that levels of P‐cadherin were increased two‐fold in dysplastic oral keratinocytes (DOK) compared to primary human oral keratinocytes (HOK) obtained from normal oral mucosa. We hypothesized that in dysplastic oral epithelia, upregulated P‐cadherin cooperates with amplified EGFR to enhance survival signaling and facilitate tumor progression. To further explore the interaction of P‐cadherin and EGFR, DOK cells were retrovirally infected to generate stably‐selected control and P‐cadherin‐overexpressing cell lines. We have previously demonstrated that the DOK cell line exhibits comparatively high levels of EGFR expression. We found that P‐cadherin overexpression increased basal, as well as EGF‐stimulated EGFR phosphorylation levels. Furthermore, this was accompanied by increased phosphorylation of a downstream effector of EGFR, signal transducer and activator of transcription (STAT3). This increased phosphorylation was not dependent on an increase in total STAT3 protein level. STAT3 phosphorylation suggested activation of a pro‐survival mechanism, a finding that was further supported by P‐cadherin‐dependent increases in the anti‐apoptotic protein Bcl‐xL. When exposed to chemotherapeutic agents such as paclitaxel and carboplatin, P‐cadherin overexpression increased cell survival compared to control cells. P‐cadherin‐overexpressing cells treated with paclitaxel also exhibited decreased apoptosis. Further analysis confirmed that the difference in cell death was not due to altered proliferation of the two cell lines. We also explored the possibility that EGFR was activated by P‐cadherin‐mediated adherens junction formation. In contrast to ligand‐dependent signaling, we observed that calcium‐dependent cadherin engagement suppressed the phosphorylation of both EGFR and STAT3. These studies suggest that the upregulation of P‐cadherin, together with increased EGFR expression, promotes tumor progression in dysplastic oral epithelia through the activation of prosurvival signaling pathways.Support or Funding InformationMidwestern University Glendale College of Osteopathic Medicine, College of Health Sciences, College of Veterinary MedicineThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
IQGAP1 Binds The Axl Receptor Tyrosine Kinase And Inhibits Its Signaling
Authors: Gorisse Laetitia , Li Zhigang , Hedman Andrew C. , Sacks David B. 
Published: June 2021

IQGAP1 is a scaffold protein that integrates cell signaling pathways by binding several growth factor receptors and intracellular signaling molecules (Trends Cell Biol 2015; 25:171–184). The Axl tyrosine kinase receptor is important in hematopoiesis, the innate immune response, platelet aggregation, engulfment of apoptotic cells and cell survival (Cold Spring Harb Perspect Biol 2013; 5:a009076). Binding of growth arrest‐specific protein 6 (Gas6) to immunoglobulin‐like (Ig‐like) domains of Axl activates intracellular signaling. However, the mechanism of inactivation of the Axl receptor is poorly understood. Here, we investigate the interaction between IQGAP1 and Axl. Using GST pulldown assays and immunoprecipitation from mammalian cell lysates, we found that IQGAP1 associates with Axl in cells. Analysis with multiple discrete fragments of each protein revealed that the binding is direct and mediated by the IQ domain of IQGAP1 and the Ig‐like domains of Axl. We observed by proximity ligation assays that Axl:IQGAP1 complexes are located in the cytoplasm, and this interaction is reduced by 64% when cells are incubated with Gas6. Consistent with these findings, reducing IQGAP1 levels in cells by CRISPR/Cas9 enhanced the ability of Gas6 to stimulate both Axl phosphorylation and activation of Akt. Moreover, reduction of IQGAP1 in cells promoted Gas6‐stimulated transcription of matrix metalloproteinase (MMP)‐2, MMP‐3, MMP‐9 and urokinase‐type plasminogen activator genes. Finally, we observed by confocal microscopy that IQGAP1 downregulates the heterodimerization of Axl with the epidermal growth factor receptor. In summary, we identify IQGAP1 as a previously undescribed suppressor of Axl. These findings differ from the previously reported functions for IQGAP1 as a scaffold that promotes signaling by growth factor receptors (J Biol Chem 2007; 292:3273–3289; J Biol Chem 2011; 286:29734–29747; J Biol Chem 2011; 286:15010–15021). Our data expand the repertoire of binding partners for both Axl and IQGAP1, and provide additional insight into the regulation of Axl function.Support or Funding InformationThis work was supported by the National Institutes of Health Intramural Research 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.