bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Tale of Two Inteins: Similar Inteins with Different C‐termini
Authors: Ramsoomair Christian K , Giaccone Zachary T , Reitter Julie N , Mills Kenneth V 
Published: June 2021

Protein splicing is a post‐translational process facilitated by an intervening polypeptide, or intein. The intein catalyzes its excision from the flanking polypeptides, or exteins, as well as ligation of the exteins. We studied inteins that interrupt the DNA Polymerase II from the cyanobacteria Synechococcus sp. PCC 7002 (Ssp) and Trichodesmium erythraeum (Tery). The two inteins differ mostly in the residues that promote the third step of splicing, side chain cyclization of the C‐terminal residue coupled to peptide bond cleavage. While the Ssp intein has a native C‐terminal Asn, the Tery intein has a native Gln. We hypothesized that the replacement of the native Asn with Gln might slow splicing, whereas replacement of the native Gln with Asn may accelerate splicing, as cyclization of Asn residues is usually considerably faster. Preliminary results suggest that our hypothesis is correct for isolated side chain cyclization, but that the overall splicing reaction is less affected by the identity of the C‐terminal residue. This suggests that conformational changes after step one, an amide to thioester rearrangement, might affect the rate of side‐chain cyclization.Support or Funding InformationThis material is based upon work supported by the National Science Foundation under grants MCB‐1244089 and MCB‐1517138, a Henry Dreyfus Teacher‐Scholar Award (KVM), and Mrs. Jeremiah W. O'Connor, Jr.
Probing the Interactions between α‐1, 4‐Mannobiose Molecules, using AFM
Authors: Perera Komitige Hashanthi , Basu Saswati , Chandran Preethi 
Published: June 2021

Carbohydrate‐carbohydrate interactions (CCIs) have been recognized to govern a wide range of biological processes including species‐recognition, fertilization, embryogenesis, and cell development (1). The goals of our study are to investigate whether mannobiose moieties exhibit CCIs and to determine the solution conditions in which the interactions occur. Mannobiose moieties are disaccharides of mannose sugars. They coat the surfaces of pathogens and immune cells and are extensively involved in host‐pathogen interactions (2). The oligosaccharides are widely used in the design of drug‐delivery vehicles for targeting cells that express mannose receptors (e.g., dendritic cells) (2) and for reducing the cytotoxicity induced by the drug‐delivery vehicles (4). Therefore, the finding of CCIs between mannobiose moieties will impact the field of immunotherapy and the design of drug‐delivery vehicles.CCIs between α‐1, 4‐mannobiose moieties were measured using the force spectroscopy (FS) mode of an atomic force microscope (AFM). The mannobiose molecules were covalently attached to thiolated linkers and assembled as monolayers on gold‐coated mica and AFM tips. The mannobiose exposure on these functionalized surfaces was verified by its selective binding of lectin concanavalin‐A. The strength of CCIs between the mannobiosylated surfaces was determined as a function of the monovalent and divalent ion concentrations in the solution, and of the pH. Control experiments were designed to measure the interactions between the thiolated linkers.Our results indicate that there are self‐adhesive interactions between the mannobiosylated AFM surfaces. These interactions tend to be in the range of 200–800 pN, and predominantly occur as multiples of ~200pN. The addition of free mannobiose significantly diminishes the adhesive forces. We are currently investigating the effect of solution conditions on the magnitude of the interactions. The conclusion of our study is that mannobiosylated surfaces exhibit complex potential for interactions, which can be harnessed for the design of immunotherapies and of drug‐delivery vehicles.Support or Funding InformationThis material is based upon work supported by National Science Foundation under grant no. 1407891 awarded to Preethi Chandran and by a mini‐grant awarded to Preethi Chandran under NSF grant no. 1208880 (PI: Dr. Sonya Smith)
WWOX coordinates with type II TGF‐beta receptor in regulating cell‐to‐cell recognition and immune cell differentiation
Authors: Chen Yu‐An , Sie Yong‐Da , Lu Chen‐Yu , Chang Nan‐Shan 
Published: June 2021

Tumor suppressor WWOX is anchored, in part, at the cell membrane/cytoskeleton area and is able to sense alterations of extracellular cues. By time‐lapse microscopy, we determined that WWOX plays an important role in controlling cell migration and cell‐to‐cell recognition. Wwox−/−MEF cells migrate individually; however, wild type Wwox+/+ MEF cells migrate collectively. When wild type Wwox+/+ MEF cells meet Wwox−/− cells, they fail to recognize each other. The knockout cells stretch out their pseudopodia to touch the wild type cells, and then move in a retrograde manner, followed by dividing immediately. The phenomenon is observed in many WWOX‐deficient cells upon encountering WWOX‐positive cells. By molecular dissection, an epitope of WWOX, namely WWgre (WWOX7–21), is responsible for attracting visiting cells. In contrast, SDRrepl (WWOX286–299) repels WWOX‐negative visiting cells. Specific antibodies against SDRrepl or WWgre block the cell‐to‐cell recognition effects. Both epitopes are physically associated with type II TGF‐beta receptor (TbetaRII). Accordingly, TGF‐beta and TbetaRII IgG antibody abolish the repellence effect. Notably, synthetic WWgre peptide is highly potent in causing T lymphocyte clonal expansion in the spleen, whereas pS14WWgre induces expansion of Hyal‐2+ CD3‐ CD19‐ (or Z) lymphocyte for memory anticancer response. Taken together, WWOX plays a crucial role in controlling cell migration, recognition, and immune cell differentiation.Support or Funding InformationMOST and NHRI, Taiwan; DoD, USA.
The Effect of Y71 Mutants on The Allosteric Switch of Ras
Authors: Charley Kelsey , Guterres Hugo , Mattos Carla 
Published: June 2021

Ras GTPase is involved in a number of signaling pathways that are responsible for the control of many cellular processes, including cell proliferation. Ras functions like a molecular switch, where its inactive form binds to GDP and its active form binds to GTP. We had shown through crystallography work that in its active form, Ras has two major conformational states, including the T‐state (tardy) and the R‐state (reactive). The R‐state is obtained through an allosteric modulation by the binding of calcium acetate in the crystal structure. Through a wild‐type accelerated molecular dynamics (aMD) simulation, we observed that residue Y71 is involved in the transitioning from R‐ to T‐state. In this study, we aim to elucidate the role of residue Y71 in the allosteric modulation of H‐Ras. We work to obtain the structure of Y71F and Y71A mutants of H‐Ras, and conduct aMD simulations for these mutants. For aMD simulation, we make Y71F and Y71A mutants using homology modeling of wild type H‐Ras structure. In lab, we made mutations using site directed mutagenesis and successfully mutate Tyrosine 71 to Phenylalanine and Alanine. We over‐expressed our mutants in Escherichia coli system, used ion exchange and gel filtration chromatography for protein purification. Our aMD simulation shows that Y71F and Y71A mutants changed the conformational balance between the R‐ and T‐states, favoring the T‐state, relative to wild type H‐Ras. We observe different dynamics in these two mutants, specifically Y71F show higher flexibility near the active site residues, relative to the wild type. Our preliminary crystallization result will also be presented. This study will help elucidate the role of a novel allosteric residue that will help in understanding the allosteric mechanism of H‐Ras.Support or Funding InformationNSF MCB‐1244203.
Enhanced Cholesterol Clearance and Bile Acid Signaling in Skin‐Specific SCD1 Deficient Mice
Authors: Dumas Sabrina , Boehmer Robert , Ntambi James 
Published: June 2021

Stearoyl‐CoA desaturase 1 (SCD1) catalyzes the rate limiting step in monounsaturated fatty acid synthesis by inserting a double bond at the delta‐9 position of long‐chain fatty acids. SCD1 converts stearate (18:0) to oleate (18:1n9) and palmitate (16:0) to palmitoleate (16:1n7). Global deletion of SCD1 in mice provides remarkable resistance to both high‐carbohydrate and high‐fat diet‐induced obesity. These mice also demonstrate improved insulin sensitivity and glucose clearance. Interestingly, skin‐specific deletion of SCD1 also provides protection from high‐fat diet‐induced obesity, and similar metabolic improvements. In addition, these mice have increased skin surface free cholesterol, decreased circulating total cholesterol and increased circulating total bile acids. Cholesterol is minimally lost by the skin, but this loss is upregulated in skin‐specific SCD1 deletion. Reduced circulating cholesterol is a well‐known cardio‐protective phenotype, whereas increased circulating bile acids are protective against weight gain via TGR5 signaling. TGR5 signaling is also related to improved insulin sensitivity. Importantly, cholesterol catabolism into bile acids is the major route of cholesterol excretion. Proteomic and genetic analysis of skin tissue of skin‐specific SCD1 deficient mice indicate upregulated TGR5 signaling, and increased cholesterol and bile acid biosynthesis.Support or Funding InformationSabrina Dumas was supported by USDA Hatch W2005.
Lead and cadmium levels in breast milk and maternal blood and their relation to inflammation markers
Authors: Zhong Yingyi , Kennedy Tay , Stoecker Barbara , Aubuchon‐Endsley Nicki L , Grant Stephanie , Hubbs‐Tait Laura , Thomas David G. 
Published: June 2021

The heavy metals cadmium and lead are well known for their toxicity to the human body. They are carcinogenic and detrimental to multiple organs, including the brain. Various factors such as drinking water, cigarette smoke exposure, and environmental pollution can impact levels of cadmium and lead in nursing mothers, subsequently exposing their infants.The objective of our study is to determine the relation between levels of cadmium and lead in maternal blood and breast milk and see whether these levels correlate with inflammation markers, including C‐reactive protein (CRP) and alpha‐1‐acid glycoprotein (AGP).At 3 month postpartum, 132 primarily white mothers were recruited into our study. Breast milk and blood samples were collected on site using techniques designed to limit trace mineral contamination. Breast milk was manually expressed and later ashed before analysis. Both the breast milk and the maternal blood samples were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP MS). AGP and CRP, inflammation markers, and soluble transferrin receptors (sTFR) were measured using ELISA kits.Lead and cadmium were positively correlated in both blood (r=0.297, p <0.01) and breast milk (r= 0.558, p<0.01).Blood lead concentrations (m=4.96 μg/L, SD=4.11) were significantly greater than breast milk lead concentrations (m=1.85 μg/L, SD=2.12); p<0.001. Blood cadmium concentrations (m=789 ng/L, SD=564) were also significantly greater than those in milk (m=228 ng/L, SD=275); p < 0.001. The mean blood levels were two and half times the mean breast milk levels for lead and nearly three times the mean breast milk levels for cadmium.Blood cadmium concentrations were positively correlated with blood CRP concentrations (r=0.287, p<0.001), while milk cadmium levels were negatively correlated with blood AGP concentrations (r=−0.201, p=0.023). In addition, blood lead concentrations were negatively correlated with sTfR concentrations (r=−0.203, p=0.022).Maternal exposures to lead and cadmium contribute to lead and cadmium in breast milk which may impact their breastfed infants. Our results suggest these minerals may not be actively transported from blood to breast milk but that inflammation might affect the transport of these metals from the blood to breast milk.Support or Funding InformationSupported by National Research Initiative Grant 2008‐35200‐18779 from the USDA National Institute for Food and Agriculture and an OSU Provost's Multidisciplinary Grant
HomeStyles: Strategies Used to Retain Parents of Preschool Children in a Long‐Term Randomized Control Trial
Authors: Delaney Colleen , Martin‐Biggers Jennifer T , Koenings Mallory , Tonnessen Rebecca , Byrd‐Bredbenner Carol 
Published: June 2021

Randomized control trials (RCTs) are the gold standard in scientific research. Keeping participants actively involved throughout the RCT is critical to success, yet little is published with regard to retention strategies. Thus, this abstract describes the strategies used in the 18‐month HomeStyles childhood obesity prevention RCT to retain parents of preschoolers. Retention strategies included 1) high‐quality, attractive, quick and easy to use intervention materials (i.e., guides) responsive to the wants and needs of parents of preschoolers in written in Spanish and English; 2) flexible 24/7 participation opportunities (e.g., web delivery; online data collection) and implementing strategies to minimize participant burden; 3) elements of surprise, such as sending fun, unexpected guide‐related enhancements (e.g., beach ball, hula hoop) and holiday or reminder cards in eye‐catching mylar envelopes; 4) program identity branding of all RCT materials using the colorful HomeStyles logo to remind parents about the project each time they noticed project materials in their homes or received electronic or mailed items; 5) financial stipends in the form of eGift cards to participants’ favorite stores immediately after completion of RCT questionnaires and opportunities to receive earn extra stipends (e.g., bonus bucks for visiting the website frequently, submitting supplementary data including height, weight, and pedometer readings); 6) consistent contact methods in the form of frequent, friendly, positive multi‐mode communication including messages in the form of encouraging and motivating nudges sent every ~4 days via email, SMS, and/or voice mail, and protocols to reach out to participants by phone, email, and mail as soon as they showed signs of inactivity; 7) immediacy, ease, and consistency, such as making communication with the RCT team easy (toll‐free phone, email) and replying rapidly to participants queries by trained staff using uniform procedures and consistent messaging; 8) English‐ and Spanish‐speaking study personnel; 9) effective research management with trained RCT team members, established protocols for all RCT procedures, frequent monitoring of participant activity and rapid application of retention procedures; 10) providing an equivalent control group intervention (Home Safety) and not labeling this group as “control”; 11) nonfinancial incentives encouraging participants to make small changes towards their goal to maintain confidence and manage stress and reminding parents to keep the goal of an even happier, healthier family at the forefront as they worked to make improvements; 12) ability to easily update contact information each time participants logged on to the project website. The retention procedures used in this RCT have the potential to improve RCT retention in a broad range of nutrition education research studies.Support or Funding InformationUSDA NIFA #2011‐68001‐30170
The Modulatory Effect of Common Dietary Fatty Acids on IPEC‐J2 Transport of Lipopolysaccharide and Monolayer Barrier Integrity in vitro
Authors: Lyte Joshua Mark , Gabler Nicholas K , Hollis James H 
Published: June 2021

Recent evidence has demonstrated the ability of dietary fatty acid composition to influence postprandial endotoxemia in humans and swine. However, the mechanism(s) by which fatty acids affect transport of lipopolysaccharide (LPS) across the intestinal epithelium has not yet been fully elucidated. To study this, we utilized non‐transformed porcine jejunum‐derived IPEC‐J2 cells. This cell line is well‐recognized to form confluent polarized monolayers with apical and basolateral regions, allowing for an in vitro model of the intestinal epithelium. The present study investigated the effect dietary fatty acids and inflammation had on intestinal permeability of LPS and barrier integrity in IPEC‐J2 monolayers. We hypothesized that treatment of IPEC‐J2 monolayer with saturated or n‐6 polyunsaturated fatty acids (PUFA) would enhance fluorescein‐isothiocyanate (FITC)‐LPS apical‐to‐basolateral permeability and reduce transepithelial resistance (TER); whereas n‐3 PUFA would attenuate this response. Secondly, we hypothesized that lauric acid would amplify the reduction in monolayer integrity associated with pre‐treatment with LPS. IPEC‐J2 cell monolayers were grown to confluency (>1kΩ) on 0.4 μm Transwell® inserts. In experiment 1, these monolayers were treated with either 50 or 100 μM of docosahexaenoic acid, lauric acid, arachidonic acid or vehicle for 48 hours before TER and FITC‐LPS determination of barrier integrity. In experiment 2, monolayers were treated with either 5 μg/mL LPS, LPS plus 100 μM lauric acid or saline vehicle for 24 hours and then TER and FITC‐LPS determination of barrier integrity assessed. In experiment 1, TER and FITC‐LPS permeability was not altered by fatty acid type or concentration. For experiment 2, compared to the saline control, LPS caused a significant time‐dependent reduction in TER (p<0.001); however, the co‐inclusion of lauric acid fatty acids did not have any additive effect on TER (p>0.05). Although TER was reduced, surprisingly we reported no treatment differences in apical to basolateral FITC‐LPS permeability. In conclusion, fatty acid treatment did not modulate barrier inflammation and permeability in in vitro IPEC‐J2 monolayers. However, live Gram‐negative bacteria or their bacterial cellular membrane fragments may be a better model to study the effects of fatty acids on LPS permeability.Support or Funding InformationResearch supported by the Agriculture and Food Research Initiative Grant No. 2014‐67017‐21778 from the USDA NIFA.
Test‐retest reliability and postprandial time course of the neural responses to visual food stimuli
Authors: Sayer R Drew , Tamer Gregory , Chen Ningning , Tregellas Jason , Cornier Marc , Kareken David , Talavage Thomas , McCrory Megan , Campbell Wayne 
Published: June 2021

The brain's reward system influences ingestive behavior and subsequently obesity risk. Functional magnetic resonance imaging (fMRI) is a common method for investigating brain reward function. We sought to assess the test‐retest reliability and postprandial time course of neural responses to visual food cues using fMRI. A priori brain regions of interest included bilateral insula, amygdala, orbitofrontal cortex, caudate, and putamen. Fasting‐state fMRI and appetite assessments were completed by 29 overweight or obese women (n=17) and men (n=12) on 2 days for test‐retest reliability analyses determined by intraclass correlation coefficient. A subset of 3 women and 4 men completed postprandial fMRI and appetite assessments 0, 90, 180, and 270 min after consuming a 300 kcal meal to document the postprandial time course of responses. Mean fasting‐state neural responses on Day 1 and Day 2 were not different in 8 of 10 regions of interest. However, test‐retest reliabilities of neural responses were mostly poor or unreliable. Only the left orbitofrontal cortex response demonstrated fair test‐retest reliability. Furthermore, neural responses to visual food stimuli were largely unaffected by meal consumption. In conclusion, fMRI‐measured responses to visual food cues in overweight and obese adults show relatively good group‐level reproducibility but considerable within‐subject variability and are insensitive to meal consumption.Support or Funding InformationAmerican Egg Board, NIH UL1 TR001108, USDA‐NIFA 2011‐38420‐20038, Purdue University Ingestive Behavior Research Center
Effects of Higher Dietary Protein and Fiber Intake at Breakfast on Postprandial Insulin and Glucose Responses in Overweight Adults
Authors: Amankwaah Akua , Sayer R Drew , Wright Amy J , Chen Ningning , McCrory Megan A , Campbell Wayne W 
Published: June 2021

BackgroundDietary protein and fiber independently influence insulin‐mediated glucose control. However, the potential additive or synergistic effects of higher protein and fiber intake on postprandial insulin and glucose responses are not known.PurposeThis study assessed the effects of protein and fiber intakes at breakfast on postprandial insulin and glucose responses.MethodsMen and women [n = 20; age: 26 ± 5 y; body mass index: 26.1 ± 0.2 kg/m2; means ± SEM] consumed provided breakfast meals with varying protein (high = 25 g vs. normal =12.5 g) and fiber (high= 8 g vs. normal = 3 g) amounts during 4, 2‐week interventions (randomized crossover experimental design). Each 2‐week period was separated by a 2‐week washout period. The breakfast variations included: normal protein and fiber (NPNF), normal protein and high fiber (NPHF), high protein and normal fiber (HPNF), or high protein and fiber (HPHF). Breakfast was provided with fixed energy (400 kcal) and digestible carbohydrate (50 g) on each day, and the remainder of daily energy intake was self‐selected. On the last day of each intervention period, a meal tolerance test was completed to assess serum glucose and insulin concentrations at fasting and hourly for 4 hours (240 min). Repeated measures ANOVA was applied for data analyses.ResultsThere were no differential responses among breakfast meals on composite postprandial insulin and glucose (240‐min total areas under the curve (AUC)) after adjusting for fasting values, sex, and breakfast treatment order. Analysis of the 0–120 min and 120–240 min AUCs supported that higher protein and/or fiber did not influence glucose responses. Further, differential responses were not observed for insulin AUC at 0–120 min but were for 120–240 min. The 120–240 min insulin AUC was numerically lowest after NPHF (880 ± 103 μU/mL) and was statistically different from HPNF (1228 ± 104 μU/mL) but not HPHF (1004 ± 104 μU/mL) or NPNF (1049 ± 108 μU/mL).ConclusionDoubling the amount of protein from 12.5 g to 25 g/meal and increasing fiber from 3 to 8 g/meal did not additively or synergistically affect postprandial insulin and glucose responses. These results do not support increasing dietary protein and fiber at breakfast as an effective strategy for modulating insulin‐mediated glucose responses in young, overweight adults.Support or Funding InformationSupport: American Egg Board‐ Egg Nutrition Center; NIH UL1TR0001108; USDA‐NIFA 2011‐38420‐20038