bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probing the lipid composition at the site of influenza virus assembly and budding with high‐resolution SIMS
Authors: Kraft Mary L. , Yeager Ashley N. , Weber Peter K. , Zimmerberg Joshua 
Published: June 2021

The formation of infectious influenza virions is sensitive to the cholesterol levels in the host cell. The findings that the influenza viral envelope is enriched with cholesterol and sphingolipids and cholesterol depletion alters the clustering of influenza virus proteins in the plasma membrane, which is detrimental to virus assembly, suggests that the influenza virus assembles and bud from cholesterol‐ and sphingolipid‐enriched domains in the plasma membrane. Although this hypothesis has been around for decades, whether the region of the plasma membrane from which the influenza virus buds is enriched with cholesterol and sphingolipids is still unknown. To answer this question, we have used high‐resolution secondary ion mass spectrometry (SIMS) to image the distributions of stable isotope‐labeled cholesterol and immunolabeled influenza virus protein in the plasma membrane during virus budding with ~100 nm lateral resolution. This work involved metabolically incorporating distinct stable isotopes into the cholesterol and lipids of interest in living MDCK cells. After infecting these MDCK cells with influenza virus for 24 h, we immunolabeled the influenza envelope protein, hemagglutinin. Then we imaged the isotope‐labeled cholesterol, lipids, and immunolabeled influenza hemagglutinin on the surfaces of the virus infected cells with ~100 nm lateral resolution. The resulting images clearly show that the influenza virus does bud from cholesterol‐enriched domains in the membranes of MDCK cells.Support or Funding InformationThis research was supported by the U.S. National Science Foundation under CHE 15‐08662.
A Prokaryotic‐like Lysophosphatidic Acid Acyltransferase Reveals Unique Features of Triacylglycerol Biosynthesis in Microalgae
Authors: Kim Yeongho , Terng Ee Leng , Riekhof Wayne , Cahoon Edgar B. , Cerutti Heriberto 
Published: June 2021

Understanding algal triacylglycerol (TAG) metabolism has strong implications for the biology of storage lipids as well as for biofuel production. Higher plants have prokaryotic (chloroplast located) and eukaryotic (endoplasmic reticulum located) pathways to synthesize specific glycerolipids. Lysophosphatidic acid acyltransferases (LPAATs) in the chloroplast prefer adding C16 fatty acids at the sn‐2 position of the glycerol backbone, generating ‘prokaryotic’ lipid precursors. In contrast, LPAATs in the endoplasmic reticulum (ER) direct the preferential esterification of C18 fatty acids at the sn‐2 position, synthesizing ‘eukaryotic’ lipid precursors. In higher plants, triacylglycerols are considered eukaryotic lipids, as they have predominantly C18 esterified at the sn‐2 position. Moreover, TAG assembly enzymes have been found to localize to the ER in diverse eukaryotes.Chlamydomonas reinhardtii, a unicellular green alga, has primarily C16 fatty acids esterified at the sn‐2 position of TAGs. This observation led to the proposal that Chlamydomonas mainly employs the prokaryotic (chloroplastic) pathway for TAG precursor biosynthesis. However, an alternative hypothesis is suggested by our characterization of a unique C. reinhardtii LPAAT, termed CrLPAAT2. In phylogenetic analyses this enzyme belongs within a Chlorophyte‐specific clade (limited to the Chlorophyceae and Trebouxiophyceae classes of green algae) and it is absent from all other eukaryotes examined. Interestingly, CrLPAAT2 displays a chimeric structure between known eukaryotic and prokaryotic LPAATs and it was found to localize to the ER. RNA‐mediated silencing of CrLPAAT2 indicated that the enzyme is required for TAG accumulation under nitrogen deprivation. We also demonstrated that CrLPAAT2 prefers as substrate C16:0‐CoA over C18:1‐CoA in vitro, by substrate competition assays, and in vivo, by complementation of a LPAAT‐defective yeast strain. Thus, Chlamydomonas (and related green algae) possesses a distinct glycerolipid synthesis pathway that relies on CrLPAAT2 to generate prokaryotic‐like TAG species (with C16 at the sn‐2 position) in the endoplasmic reticulum.Support or Funding InformationThis research is funded by EPSCoR (1004094).
Retention of provitamin A carotenoids in high‐provitamin A biofortified maize and eggs after various cooking methods
Authors: Sowa Margaret , Goltz Shellen , Tanumihardjo Sherry A. 
Published: June 2021

Biofortification of staple crops to increase the content of provitamin A carotenoids (such as beta‐carotene and beta‐cryptoxanthin) is a strategy being implemented to increase dietary intake of vitamin A in regions where deficiency presents a widespread problem. Heat and light can cause isomerization and oxidation of carotenoids, potentially reducing the provitamin A activity of foods made with biofortified maize after cooking and processing. Thus, an understanding of the provitamin A retention after cooking is important for assessing the utility and maximizing the efficacy of biofortified foods. Retention of carotenoids in eggs from chickens fed high‐beta‐cryptoxanthin maize was assessed after frying, boiling, and microwaving. Retention of carotenoids in high‐beta‐cryptoxanthin maize was assessed in muffins, tortillas, porridge, and fried polenta made from both whole‐grain and sifted maize flour. This work demonstrates that provitamin A retention may be influenced by cooking, and processing methods should be taken into consideration when breeding and implementing biofortified maize varieties.Support or Funding InformationSupported by USDA Hatch WIS01804, Global Health Funds at UW‐Madison, and Harvest Plus breeding contract 5204.
Prolonged High Altitude Exposure Results in Elevated Erythroferrone and Diminished Hepcidin Levels in Healthy Young Male Volunteers
Authors: McClung James P , Hennigar Stephen R. , Berryman Claire E. , Young Andrew J. , Pasiakos Stefan M. 
Published: June 2021

Iron, an essential micronutrient, supports physical and cognitive performance through the binding of proteins and enzymes involved in oxygen transport and energy metabolism. High altitude (HA) acclimatization affects iron metabolism and results in increased hemoglobin concentrations due to hypoxia‐stimulated hemoconcentration and erythropoeisis. Iron homeostasis is regulated by hepcidin, aprotein affecting iron absorption and metabolism through the binding and degradation of ferroportin, the primary cellular iron exporter. Erythroferrone, a recently identified hormone, inhibits hepcidin transcription during erythropoiesis in animal models. As hepcidin and erythroferrone have not been assessed in human volunteers exposed to HA, the primary objective of the present study was to explore the effects of HA on hepcidin, erythroferrone, andiron availability. Hemoglobin, hepcidin, erythroferrone, and serum iron were measured in unacclimatized healthy youngmen (n = 17, age [mean ± SD] = 23.4 ± 5.6 yrs, body weight = 81.9 ± 13.9 kg) residing at sea level(SL) and HA (19 d, 4300 m). While residing at HA, volunteers consumed energy restricted diets providing 70% of SL weight maintenance energy needs, and engaged in prescribed physical activity to induce a 40% total daily energy deficit. As compared to SL, HA resulted in increased hemoglobin (16.6 ± 0.9 vs. 14.3 ± 0.8 g/dL, P <0.01), diminished hepcidin (4.8± 3.4 vs. 7.5 ± 3.4 ng/mL, P <0.05), and increased erythroferrone (3.1 ± 2.1 vs. 0.9 ± 0.6pg/mL, P < 0.01). Serum iron increased at HA as compared to SL (104.7 ± 34.2 vs. 65.4 ± 17.4μg/mL, P < 0.01). Taken together, these data indicate that prolonged HA exposure in humans results in elevated erythroferrone, which is associated with suppressed hepcidin transcription and increased iron availability.Support or Funding InformationResearch supported by the US Army Medical Research and Materiel Command. The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the US Government.
Food Group Intake Differs among Adult Food Secure, Low Food Secure and Very Low Food Secure Rural, Midwestern Emergency Food Pantry Users
Authors: Wright Breanne N. , McCormack Lacey A. , Stluka Suzanne , Contreras Dawn , Franzen‐Castle Lisa , Henne Becky , Mehrle Donna , Remley Dan , Eicher‐Miller Heather A. 
Published: June 2021

ObjectivePrevious research has documented the high prevalence of food insecurity, or uncertain access to healthy foods, and poor dietary intake in emergency food pantry (EFP) users. However, no studies have determined whether there are differences in dietary intake when stratified by food security status within the EFP population. This study evaluated associations between food security status and the intake of key nutrients and food groups among EFP clients.Study Design, Setting and ParticipantsAdult EFP clients (n=445) from a multistate sample of 24 rural, Midwestern EFPs participated at a single time point from September–November 2014.Outcome Measures and AnalysisParticipants completed a characteristics survey, the 18‐item U.S. Household Food Security Survey Module, and up to three National Cancer Institute Automated Self‐Administered 24‐hour dietary recalls (ASA24s). Adult food security status, classified as food secure, low or very low food secure, was the independent variable while mean intake of energy, vitamins, minerals, and food groups were dependent variables. Multiple linear regression models adjusted for energy and other confounders were used to determine associations between food security status and nutrient/food group outcomes.ResultsLow adult food security was significantly positively associated with total energy (kcal) intake (β=245.81 p=0.02) compared with very low food security. Adult food security was significantly positively associated with whole fruit (cup equivalents) intake (β=0.17 p=0.04) compared with low food security.Conclusions and ImplicationsResults suggest that food security, low food security, and very low food security status may be specifically associated with the consumption of key food groups and therefore differences in dietary intake by food security range should be considered in the development of future initiatives that target this population.Support or Funding InformationThis project is supported by the Agriculture and Food Research Initiative competitive grant no. 2013‐69004‐20401 of the USDA National Institute of Food and Agriculture.
Gut microbiota dictate metabolic Fate of Curcumin in the colon
Authors: Li Zhengze , Sun Yue , Song Mingyue , Li Fang , Xiao Hang 
Published: June 2021

The metabolic fate of dietary bioactive compounds play critical roles in their health effects. Herein, we determined the metabolic fate of curcumin in the gastrointestinal (GI) tract of mice after long‐term dietary administration of curcumin for 6 weeks. Our results demonstrated that in the GI tract curcumin underwent phase I metabolism to yield three metabolites, namely tetrahydro‐curcumin (M1), hexahydro‐curcumin (M2) and octahydro‐curcumin (M3). Curcumin and these phase I metabolites then were subject to phase II metabolism to yield their corresponding conjugated phase II metabolites. The above‐mentioned metabolism of curcumin occurred in the stomach but to a much less extent than that in the small intestine. Only phase II metabolites of curcumin could be found in the small intestine (i.e., conjugated forms of curcumin, M1 and M2), while only phase I metabolites of curcumin could be detected in the cecum and colon (i.e., M1 and M2). This suggested that gut microbiota might be responsible for the deconjugation of phase II metabolites that converted them back to the corresponding phase I metabolites in the cecum and colon. Indeed, anaerobic fermentation of phase II metabolites (isolated from the small intestine of curcumin‐fed mouse) by both mouse and human fecal bacteria deconjugated them to yield phase I metabolites. Moreover, fecal bacteria were able to transform curcumin to yield M1, M2, and M3, and they can further breakdown these four compounds to yield fission products such as ferulic acid. To confirm the role of gut microbiota in biotransformation of curcumin, curcumin‐fed mice were treated with or without dextran sulfate sodium (DSS) in the drinking water (DSS is an agent capable of altering gut microbiota, and we confirmed the altered microbiota by DSS via next generation sequencing of fecal microbiota). Analyses of colonic content by LC/MS demonstrated that in comparison with the control mice, DSS‐treated mice had a completely different curcumin metabolite profile in the colon, i.e., much higher levels of phase II metabolites and much lower levels of fission products of curcumin. Overall, our results demonstrated that composition of gut microbiota had a profound impact on the biotransformation of curcumin in the colon, which might have a significant influence on the health effects of dietary curcumin, especially in the colon.Support or Funding InformationThis study was partially supported by fund from USDA.
Green Tea Extract Protects Against Hepatic NFκB Activation Along The Gut‐Liver Axis in Diet‐Induced Obese Mice With Nonalcoholic Steatohepatitis By Reducing Endotoxin and TLR4/MyD88 Signaling
Authors: Li Jinhui , Chitchumroonchokchai Chureeporn , Kim Joshua B. , Sasaki Geoffrey Y. , Moller Meredith V. , Bouranis John A. , Bruno Richard S. 
Published: June 2021

Green tea extract (GTE) reduces NFκB‐mediated inflammation during nonalcoholic steatohepatitis (NASH). We hypothesized that its antiinflammatory activities would be mediated along the gut‐liver axis in a Toll‐like receptor‐4 (TLR4)‐dependent manner. Wild‐type (WT) and loss‐of‐function TLR4‐mutant (TLR4m) mice were fed a high‐fat diet containing 0 or 2% (w/w) GTE for 8 wk before assessing NASH, NFκB‐mediated inflammation, TLR4 adaptor proteins [myeloid differentiation 88 (MyD88) and TIR‐domain‐containing adapter‐inducing interferon‐β (TRIF)], circulating endotoxin, and intestinal tight junction proteins. In WT mice, phosphorylation of the NFκB p65 subunit and NFκB‐dependent gene expression (MCP‐1, iNOS, MPO) were lower in those provided GTE, and were not different from the lowered levels in TLR4m mice regardless of GTE. Compared with WT controls, TLR4m mice had lower TLR4 mRNA expression, and its expression was lowered by GTE in both genotypes. Protein expression of TRIF, which mediates MyD88‐independent TLR4 signaling, was unaffected by genotype and GTE. In contrast, MyD88 expression was lower in mice fed GTE regardless of genotype. Serum endotoxin was not exacerbated in TLR4m mice, but was lowered by GTE in both genotypes. Similarly, duodenal and jejunal claudin‐1 (CLDN‐1) mRNA expression were not affected in TLR4m mice, but GTE increased their expression in both genotypes. Serum endotoxin was inversely correlated with duodenal and jejunal CLDN‐1 (rp= −0.58 to −0.43, p<0.05), and positively correlated with expression levels of TLR4 and phosphorylated‐p65 (rp= 0.46–0.57; p<0.05). Thus, GTE protects against inflammation during NASH, likely by limiting gut‐derived endotoxin translocation and TLR4/MyD88‐dependent NFκB activation.Support or Funding InformationSupported by USDA‐NIFA.
Plant Polyphenol Extract Regulated Diacylglycerol Acyltransferase and Tristetraprolin Gene Expression in Cultured Mouse Cells
Authors: Cao Heping , Sethumadhavan Kandan , Anderson Richard 
Published: June 2021

Bioactive componentsin plant products have been used for the prevention and treatment of various diseases since ancient history. One of the major classes of bioactive compounds is plant polyphenols, which are found in plant seeds, fruits, leaves and bark. Previous studies have shown that cinnamon is beneficial to people with insulin resistance due in part to the insulin‐like activity of cinnamon polyphenol extract (CPE). The objective of this study was to investigate the effects of CPE, cottonseed extract and insulin on the expression of diacylglycerolacyltransferase (DGAT) and tristetraprolin(TTP), two important gene families whose protein products are related to fatbiosynthesis and anti‐inflammatory response in mammalian cells. DGATs areintegral membrane proteins that catalyze the last step of triacylglycerols (TAGs)biosynthesis in eukaryotic organisms. Plants and animals deficient in DGATs accumulate less TAGs and over‐expression of DGATs increases TAGs. DGAT knockoutmice are resistant to diet‐induced obesity. This study used cultured mouse3T3‐L1 adipocytes and RAW264.7 macrophages. The pre‐adipocytes were induced to oil‐droplet‐filled adipocytes and subsequently treated with insulin (0, 10 and 100 nM) and CPE (0, 10 and 100 μg/ml) for 0, 30, 60, 90 and 120 min. RAW macrophages were treated with CPE (100 μg/ml), insulin (100 nM) and lipopolysaccharides (LPS, 0.1 μg/ml) for 0, 30, 60, 120 and 240 min. Total RNAs were extracted from the cells and converted into cDNAs. TaqMan quantitative real‐time PCR was used to evaluate mRNA levels of mouse DGAT1, DGAT2 and TTP genes using RPL32 and UBQLN3 as internal references. Results showed that DGAT mRNA levels were generally decreased and ZTTP mRNA levels were modestly increased by insulin and CPE in adipoctyes. Insulin and CPE effects on DGAT2 and TTP gene expression were modestly increased but LPS increased TTP mRNA levels up to50‐fold in macrophages. The results from cottonseed extracts will be discussed. Our results support the idea that CPE has insulin‐like effects and suggest apotential positive effect of CPE in reducing fat biosynthesis in adipocytes and increasing anti‐inflammatory activities in macrophages. The significance of this study is that CPE could be potentially useful for obesity prevention.Support or Funding InformationSupported by USDA‐ARS Quality and Utilization of Agricultural Products Research Program 306 through CRIS 6054‐41000‐103‐00D.
Differential effects of isoproterenol and omecamtiv mecarbil on the contractile properties of unloaded myocytes
Authors: Isaac Joslyn Deeann , Buckley Tori Dawn , Campbell Kenneth S. 
Published: June 2021

Patients develop heart failure when their ventricles are unable to maintain adequate cardiac output with normal filling pressures. Omecamtiv mecarbil is a novel small molecule that binds to the myosin head and enhances the rate of Pi release. It is currently in clinical trials as a potential therapy for heart failure. We compared the effects of omecamtiv mecarbil and isoproterenol, a well‐known β‐adrenergic agonist, on the contractile properties of single unloaded cardiac myocytes. Cells were isolated by enzymatic digestion from 3 to 6 month old female Sprague‐Dawley rats and electrically stimulated at 0.5 Hz at 32°C. Sarcomere length shortening profiles were measured using high speed video microscopy. Calcium transients were measured by monitoring Fura‐2AM fluorescence. Experiments measured the effects of 0, 0.1, 1.0, and 10.0 μM omecamtiv mecarbil and 0, 0.01, 0.1, and 1.0 μM isoproterenol. Statistical tests were performed using linear mixed models with Tukey post‐hoc criteria. Isoproterenol increased shortening (p<0.001) and accelerated the rate of shortening and relaxation (both effects, p<0.001). In contrast, 10 μM omecamtiv mecarbil reduced shortening (p<0.001) and slowed shortening and subsequent relaxation (both effects, p<0.001). Our working hypothesis is that at high concentrations, omecamtiv mecarbil increases the duty ratio of myosin heads thereby increasing the number of bound cross‐bridges. These cross‐bridges impose a drag on the myofilaments and slow contraction and relaxation.Support or Funding InformationAHA GRNT2546003, NSF 1538754, NIH TR000117, APS STRIDE, APS UGSRF, HL115473.
Inhibiting pathways involved in B‐cell development enhances sensitivity of B‐cell acute lymphoblastic leukemia to glucocorticoids
Authors: Pufall Miles A , Kruth Karina , Fang Mimi A , Shelton Dawne , Abu‐Halawa Ossama , Tasian Sarah K , Kampmann Martin 
Published: June 2021

Glucocorticoids, such as dexamethasone (dex), are used in combination chemotherapy for leukemias and lymphomas. Dex activates the glucocorticoid receptor (GR), which in turn regulates genes that induce cell death. Although dex is a remarkably effective therapeutic, some patients are insensitive to it, and others develop resistance. From among the thousands of GR‐regulated genes, it is not known which are required to induce cell death, nor how resistance arises in most cases. To understand which GR regulated genes drive lymphoid cell death, and which signaling pathways modulate dex‐sensitivity, we took an integrated functional genomic approach. We first identified sets of dex‐regulated genes by measuring differential gene expression in a panel of childhood B‐cell acute lymphoblastic leukemia (B‐ALL) primary samples and cell lines. We then performed a next‐generation genome‐wide shRNA screen to identify genes that affect growth and sensitivity to dex in B‐ALL. By comparing regulation and effect on sensitivity we essentially validated all genes en masse in B‐ALL, and were able to show that only 10% of dex‐regulated genes contributed to cell death. These genes predominantly function in transcription regulation and B‐cell development. This screen also identified cellular pathways that modulate dex‐induced death, including the B‐cell receptor pathway (BCR), a key checkpoint in B‐cell development. By integrating the gene expression and shRNA data sets we identified a double‐negative feedback loop between GR and PI3Kδ, a lynchpin in the BCR and IL7R pathways. Inhibition of PI3Kδ attenuated phosphorylation of GR, enhanced dex‐induced gene regulation, and restored sensitivity to even highly resistant B‐ALL specimens. Thus, this work elaborates with high resolution fundamental mechanistic details of GR function, and, in doing so, identifies numerous opportunities for enhanced lymphoid‐specific combination chemotherapy.Support or Funding InformationNIH, NSF, Carver Charitable Trust, V Foundation