bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relaxation of bladder smooth muscle by flavonoids from Sophora flavescens via direct activation of the large‐conductance calcium‐activated potassium channel.
Authors: Han Jisun , Lee Sojung , Lee Narasaem , Jo Hee‐Ji , Park Chul‐seung 
Published: June 2021

The large‐conductance calcium‐activated potassium channel (BKCa channel) plays critical roles in smooth muscle relaxation. In urinary bladder, BKCa channel activity underlies the maintenance of the resting membrane potential and the phasic relaxation. We recently reported kurarinone, a flavonoid found in S. flavescens, as a potent activator of the BKCa channel and thus a strong relaxant of bladder smooth muscle (Lee et al., Mol. Pharmacol., 2016). Since the potentiating effects of flavonoids with similar chemical structures vary significantly, we further screen the flavonoids of S. flavescens. We newly identified three more flavonoids from S. flavescens as potent activator of BKCa channel. In particular, kuraridinol, a prenylated chalcone, strongly activates BKCa from the extracellular side by stabilizing its open conformation. This compound markedly affects the gating kinetics of the channel by stimulating faster opening and slower closing. In order to identify new potent activators of BKCa channel from other natural sources, we are currently screening a flavonoid library using a cell‐based fluorescence assay. Thus, the flavonoids can be an excellent natural source of BKCa channel activators that may be of therapeutic benefit for targeting channel activity.Support or Funding InformationKorea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries(IPET) through Agri‐Bio industry Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affairs(MAFRA)(2017‐352)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
An Astrocyte Model Looking Toward Understanding Neurodeneration
Authors: Corcoran Ellen , Hemkin Sheryl 
Published: June 2021

Astrocytes, the most numerous subtype of glial cell in the central nervous system, have been previously identified as key regulators of neural systems due to their ability to maintain neurochemical homeostasis in the central nervous system. There is growing evidence that astrocytes not only have a supportive role in regulation, but are active partners in the information transfer processes within the brain. A healthy astrocyte can, under unknown circumstances, be transformed to a pathogenic or “reactive” astrocyte. This astrocyte form has been linked to neurodegeneration and enigmatic diseases such as Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis. It is postulated that intercellular signals shuttled through the astrocyte may be at least partially responsible for this neural degeneration, and extracellular stimuli to the astrocyte, such as by glutamate, ATP or TNFα, may cause changes in the oscillatory behavior of the cytosolic calcium and thus cause the downstream signaling. This work proposes a new model to help gain insight as to neuroinflammatory signals alter intracellular calcium dynamics, disrupt astrocyte metabolism, and ultimately facilitate neurodegeneration.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Biochemical Characterization of the Drosophila Methionine Sulfoxide Reductase A
Authors: Tarafdar Sreya , Kim Geumsoo , Rusan Nasser , Levine Rodney 
Published: June 2021

Stereospecific reduction of S‐methionine sulfoxide to methionine is enzymatically catalyzed by methionine sulfoxide reductase A (MsrA) which plays an important role in defense against oxidative stress. Recent work from our laboratory has shown that mammalian MsrA is not only a reductase, but also a methionine oxidase, capable of stereospecifically catalyzing both the oxidation of Met in proteins to S‐methionine sulfoxide (S‐MetO) as well as reduction of S‐MetO back to Met. We reported that mammalian MsrA stereospecifically and selectively oxidizes Met77 in calcium‐bound calmodulin and can fully reduce it as well. The control mechanism that prevents futile cycling is hypothesized to be through interaction with a postulated regulatory protein. Thus, cyclic oxidation and reduction of methionines in proteins by MsrA could function as a redox‐based mechanism of cellular regulation. Our aim in this study was to elucidate the physiological significance of methionine sulfoxide reductase A mediated reversible oxidation of calmodulin Met77 in Drosophila. However, we found that Drosophila MsrA, unlike its mammalian counterpart, is not a methionine oxidase. This led us to explore the mechanistic details of the enzyme. Using a double alkylation approach with HPLC‐mass spectrometric sequencing, we found that the active site cysteine residue in Drosophila MsrA becomes locked in a disulfide bond with the terminal cysteine residue of the protein and thus cannot mediate oxidation. We also created a mutant Drosophila MsrA lacking the two C‐terminal cysteine residues, reasoning that the lack of the resolving cysteines may allow the active site cysteine to mediate both oxidation and reduction of its substrates. However, this mutant Drosophila MsrA also lacked oxidase activity, despite not being able to form a disulfide bond with the active site cysteine. We are currently determining the solution structure of the Drosophila MsrA to understand the structural basis for its difference in catalytic capability from the mammalian enzyme.Support or Funding InformationThis research was supported by the Intramural Research Program of the NIH, NHLBIThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Identification of Batrachochytrium dendrobatidis inhibiting isolates via challenge against salamander skin microbiota.
Authors: Erdman Fantasia Marie , Hill Aubree , Russell Gabrielle , Griffith John , Wharton Megan , Walker Donald 
Published: June 2021

Rapid declines in global amphibian populations can be partially attributed to chytridiomycosis caused by the fungus Batrachochytrium dendrobatidis (Bd). Due to how quickly it has spread worldwide, and the number of amphibians affected, this fungus is of increasing concern in both the herpetological and mycological communities. We characterized the cutaneous microbiome of Appalachian salamanders, which persist in the presence of the fungus despite high rates of infection in co‐occurring frog populations. The cutaneous microbiome of vertebrates is known as the first line of defense against invading pathogens. We hypothesized that these salamanders might have resident bacteria on their skin with the ability to inhibit Bd growth. Our objectives were to 1) isolate resident bacteria from salamander skin swabs, 2) challenge these isolates against Bd, and 3) genotype all inhibitory isolates. During the summer of 2016, 82 swabs were collected from three salamander genera including Desmognathus (n=36), Eurycea (n=20), and Plethodon (n=26). To isolate cutaneous bacteria, swabs were streaked on Reasoner's 2A agar plates that we checked daily for two weeks. Colonies with unique morphology were isolated onto secondary plates until pure cultures were obtained. To challenge the isolates against Bd, zoospores were harvested from cultures that had been aged 5–7 days, counted with a hemocytometer, and diluted to approximately 1,000,000 cells/milliliter (mL). Tryptone agar plates were then flooded with 1.0 mL of standardized zoospore solution and dried for 45 minutes in a laminar flow hood. Bacterial isolates were streaked onto each plate in co‐culture with Bd. Plates were incubated at room temperature for four days, examined for noticeable zones of inhibition (ZOI), measured in millimeters. Isolates that produced a measurable ZOI were photographed and will be screened in further testing against Bd. We used direct colony PCR and Sanger sequencing to identify all inhibitory isolates. Presently, 63 of the 472 acquired isolates have been challenged, 16 of which produced a ZOI. The challenge phase is ongoing and we anticipate discovery of additional candidate probiotic species. In addition, we plan to test for possible synergistic inhibition by challenging candidates in polyculture.Support or Funding InformationGreat Smokey Mountains Conservation Association and Tennessee Herpetological SocietyThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Metabolism of Fluoropyrimidine Anticancer Drugs by the Human Gut Microbiome
Authors: Spanogiannopoulos Peter , Patteron Andrew D. , Turnbaugh Peter J. 
Published: June 2021

The treatment of cancer is notoriously difficult due to the high toxicity of the current medications and unpredictable variations between patients. Genetic polymorphisms within the human genome are certainly important, but they often fail to explain most of the observed variation in treatment outcomes in patients. We propose that the human gut microbiome is a major contributor to the inter‐individual variation in anticancer drug response and hypothesize that this microbial reservoir harbors determinants of resistance towards anticancer drugs, including genes responsible for drug metabolism. We are focusing on the oral cancer drug capecitabine (CAP), a prodrug of 5‐fluorouracil (5FU), due to its widespread administration for colorectal and other cancers, the unexplained differences in drug efficacy and toxicity, and studies suggesting that the mechanism of action and metabolism of this class of compounds (fluoropyrimidines) is conserved in bacteria. Here, we assessed the reciprocal interactions between CAP and 5FU and the human gut microbiome. Ex vivo incubations of human gut microbial communities demonstrated that CAP and 5FU impacts the cellular integrity and growth of gut bacteria. We determined the minimum inhibitory concentration of 5FU versus a diverse collection of 50 individual human gut bacterial type strains. Interestingly, gut bacteria showed a remarkable high variation of sensitivity towards 5FU, ranging over four orders of magnitude. Using a bioassay, we screened 5FU‐resistant gut bacteria for their ability to inactivate 5FU. Several gut bacteria, including Escherichia coli, were capable of 5FU inactivation. Mass spectrometry analysis showed that E. coli converts 5FU to the less active metabolite dihydrofluorouracil (DHFU). This activity is dependent on the preTA operon, which encodes the enzyme dihydropyrimidine dehydrogenase (DPD), as a preTA‐knockout strain of E. coli fails to metabolize 5FU. Orthologs of DPD are found in other gut bacterial species and their ability to metabolize 5FU is being investigated. Such microbial enzymes from the gut microbiome may influence the pharmacokinetics and toxicity of anticancer drugs. Additional studies in animal models and human cohorts are needed to evaluate the clinical relevance of these findings and their utility in improving clinical medicine.Support or Funding InformationPeter Spanogiannopoulos is supported by a Canadian Institutes of Health Research Postdoctoral Fellowship.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Twin Talk Series: A novel method to foster peer‐to‐peer pedagogical training
Authors: Brown Ashley K. , Martínez‐Gálvez Gabriel , Coffman Kirsten E. , Matchett William E. , Horazdovsky Bruce F. 
Published: June 2021

Mayo Clinic annually trains over 1000 predoctoral students and postdoctoral research fellows in medicine and biomedical sciences. However, training opportunities are limited for those interested in teaching and mentoring methodologies. Therefore, Mayo Clinic predoctoral students sought to provide trainee‐led learning opportunities for fellow trainees. A survey was sent to all Mayo Clinic predoctoral and postdoctoral trainees to determine preferences for pedagogy education formats. In response to survey results, the Twin Talk Series was developed. A Twin Talk is a set of one‐hour talks comprised of a Take‐in session and one or more Try‐out session(s). At the Take‐in session, a content expert discusses a pedagogical technique, and at the following Try‐out session(s), trainee volunteers practice the technique among themselves. Eight Twin Talks have been organized to date on several teaching techniques and pedagogical development topics. The impact of each Twin Talk, including understanding, format, and interest level, was evaluated through survey tools. Survey results suggested trainees favored in‐person pedagogy expert presenters during the Take‐in session over video conferences. Furthermore, modeling of the teaching technique by the expert presenter during the Take‐in session was well‐received. However, participation in the follow‐up Try‐out practice session was limited. Overall, the Twin Talk Series is a promising method for trainee‐led, peer‐to‐peer pedagogy education, particularly at institutions with limited access to pedagogical resources. The Twin Talk Series will continue to be refined to increase trainee participation, particularly in the follow‐up Try‐out sessions, and to provide relevant opportunities for trainees to practice teaching.Support or Funding InformationMayo Foundation of Medical Education and ResearchThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Elucidating the Role of a Putative Monooxygenase in the Catabolism of Nicotinic Acid and Nicotine by Bacillus niacini
Authors: Fine Sydney , Snider Mark J. 
Published: June 2021

N‐Heteroaromatic compounds (NHACs) comprise a class of molecules that are commonly found in pharmaceuticals, personal care products, and pesticides and are known to have toxic effects on the environment. Intriguingly, certain species of soil‐dwelling bacteria have the innate ability to degrade particular NHACs. A better understanding of how these soil bacteria degrade NHACs has important implications in the development of bioremediation techniques to remove toxic compounds from the environment. This investigation focuses on developing preexisting hypotheses in regards to how Bacillus niacini, a ubiquitous species of soil bacteria, degrades nicotinic acid (NA) and nicotine, both of which are NHACs. It has been hypothesized that the non‐canonical NA degradation pathway in B. niacini involves a reaction in which 2,6‐dihydroxynicotinic acid undergoes oxidative decarboxylation to form 2,3,6‐trihydroxypyridine by a enzyme termed NicC‐like. The identity of the nicC‐like gene has yet to be established. A novel transformation technique was developed to generate a B. niacini knock out variant lacking the putative nicC gene. Though there are hypotheses regarding the identity of the nicC‐like gene and its involvement in NA catabolism, sequence analysis indicates that the nicC‐like gene is only 21% similar to the nicC gene involved in NA degradation in Pseudomonas putida. In contrast, the nicC‐like gene is 24% similar to HspB, which encodes an enzyme involved in nicotine degradation. Additionally, the structure and the associated catabolic processes of nicotine and NA are similar, suggesting that the novel nicC‐like gene in B. niacini might play a role in either nicotine or NA degradation. Preliminary HPLC evidence indicates that B. niacini does not degrade nicotine. Thus, the genes currently hypothesized to encode the genes necessary for NA catabolism do not code for nicotine degradation enzymes. Characterizing the reaction catalyzed by the putative NicC‐like enzyme and determining whether or not B. niacini catabolizes nicotine has led to an improved understanding about the genes necessary for NA degradation by this particular species of pervasive soil bacteria. Continued contributions to this field may eventually lead to the development of techniques to remove NHACs from the environment.Support or Funding InformationHenry J. Copeland Fund for Independent Study at the College of WoosterThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Chebulic Acid against t‐BHP‐induced effect via Modulations of Nrf2 and Its Related Enzymes in HepG2 cells
Authors: Lee Kwangwon , Jung Hye‐Lim , Yang Sung‐Yong 
Published: June 2021

Chebulic acid, phenolic compound isolated from the ripe fruits of Terminalia chebular Retz. shows diverse biological effects. The purpose of this study is to investigate protective effects of chebulic acid against tert‐butyl hydroperoxide (t‐BHP) induced oxidative stress and its mechanism related to Nrf2 signal pathway in HepG2 cells. Chebulic acid attenuated cell death and production of reactive oxygen species in t‐BHP‐induced HepG2 cells and increased intracellular glutathione (GSH) content and the ratio of GSH to glutathione disulfide (GSSG). Chebulic acid also upregulated the activity of heme oxygenase‐1 (HO‐1). The treatment with chebulic acid increased the translocation of Nrf2 into the nucleus and the expression of Nrf2 target genes such as γ‐glutamate cysteine ligase and HO‐1 in a dose‐dependent manner. In addition, the exposure of chebulic acid enhanced the phosphorylation of mitogen‐activated protein kinases (MAPK). The overall result is that chebulic acid has cytoprotective effect on t‐BHP‐induced hepatotoxicity in HepG2 cells through Nrf2‐mediated antioxidant enzymes and MAPK.Support or Funding InformationThis work was supported by a Grant from the Institute of Life Science and Natural Resources, Korea 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.
Ubiquinone is a Key Antioxidant during Long Chain Fatty Acid Metabolism in Escherichia coli
Authors: Agrawal Shashank , Jaswal Kanchan , Shiver Anthony , Balecha Himanshi , Patra Tapas , Chaba Rachna 
Published: June 2021

Long chain fatty acids (LCFAs) are a rich source of energy for several bacteria including many important pathogens. However, LCFAs also induce oxidative stress. It is thus important to understand the reason for LCFA mediated oxidative stress and the strategies employed by bacteria to counteract this stress. In this study, we establish that fatty acid uptake and degradation is the reason for LCFA mediated oxidative stress in Escherichia coli. Our genetic screen in E. coli on the LCFA, oleate, and its comparison with published genome‐wide screens on multiple carbon sources reveals that among various electron transport chain (ETC) components, genes involved in the biosynthesis of ubiquinone, an electron carrier in ETC are highly required for growth in LCFAs compared to other carbon sources. Detail genetic and biochemical experiments suggest that the increased requirement of ubiquinone on oleate is to counter elevated levels of reactive oxygen species (ROS) generated by LCFA degradation. Additionally, we find that among various oxidative stress combat players in E. coli, ubiquinone is the major antioxidant and acts as the cell's first line of defense against LCFA‐induced oxidative stress. Intriguingly, we find that whereas the requirement of other ETC components is inversely correlated with the energy yield of non‐fermentable carbon sources, the requirement of ubiquinone correlates with oxidative stress. Our results thus suggest that the known electron carrier function of ubiquinone cannot solely explain the antioxidant role of ubiquinone. The mechanism by which ubiquinone combats ROS would depend on the major site of ROS formation during LCFA degradation. We suggest that FadE, a flavoenzyme involved in β‐oxidation that reduces FAD to FADH2 could be a predominant site of ROS formation during LCFA metabolism. It is likely that ubiquinone enables the rapid transfer of electrons from FadE to ETC thereby limiting ROS formation. In this direction, we are currently trying to establish the biochemical activity of FadE and its role in re‐oxidizing FADH2. Taken together, our studies on the role of ubiquinone during LCFA metabolism would provide a rationale to investigate the contribution of this key ETC component in managing oxidative stress in LCFA‐utilizing pathogenic bacteria.Support or Funding InformationThis work was supported by start‐up funds from IISER‐Mohali to Rachna Chaba and was partly funded by CSIR Govt. of India to Rachna Chaba.Shashank Agrawal : Supported by a fellowship from IISER‐Mohali for doctoral work.Kanchan Jaswal : Recipient of a DST‐Inspire fellowship for doctoral work.Himanshi Balecha : Supported by a fellowship from DST‐Inspire for undergraduate studies.Tapas Patra : Supported by a fellowship from IISER‐Mohali for postdoctoral workThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Long‐Chain Acyl‐CoA synthetase 6 deficiency reduces the omega‐3 fatty acid DHA in the brain and disrupts motor control
Authors: Ellis Jessica M. , Fernandez Regina F. , Zhao Yingwei , Counihan Jessica L. , Nomura Daniel K. , Chester Julia A. 
Published: June 2021

Docosahexaenoic acid (DHA) is an omega‐3 fatty acid that is highly abundant in the brain and thought to confer neuroprotection against many diseases and disorders through its anti‐inflammatory and antioxidant actions, yet the fundamental mechanisms regulating the enrichment of DHA in brain remain enigmatic. The metabolism of fatty acids at the cellular level is controlled, in part, by a family of enzymes called Acyl‐CoA Synthetases (ACSs) which perform an energy‐requiring reaction that constitutes the first and required step for nearly every cellular lipid metabolic pathway. Of the identified ACSs, one in particular, Acsl6, appears to be brain specific and its manipulation has been shown to regulate DHA metabolism in vitro. To determine the role of Acsl6 in vivo, we generated a conditional Acsl6‐deficient mouse model (Acsl6−/−). The loss of mouse Acsl6 decreases cerebellar DHA‐containing phospholipid species by 35–72%, and increases arachidonic acid‐, an omega‐6 fatty acid, containing phospholipids 120–200%. Despite the loss of DHA in brain phospholipids, the Acsl6−/− and control inflammatory response to an acute pro‐inflammatory lipopolysaccharide intraperitoneal injection was similar. However, Acsl6−/− mice present with motor dysfunction as evidenced by impaired performance in a wire hang test and reduce startle response to acoustic stimuli. Acsl6−/− brains have reduced glutathione, increased mRNA expression of the oxidative stress‐related transcription factor Nrf2, and increased GFAP protein abundance. Together these data suggest that ACSL6 is required for enriching the brain with the neuroprotective omega‐3 fatty acid, DHA, and that the loss of Acsl6 impairs motor function, increases oxidative stress and promotes astrocyte reactivity in the brain.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.