bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gestational weight gain and child weight status at 5 years of age: differential effects by prepregnancy body mass index status
Authors: Hinkle Stefanie Nicole , Sharma Andrea J , Swan Deanne W , Schieve Laura J , Stein Aryeh , Ramakrishnan Usha 
Published: June 2021

In 2009, IOM released recommendations for gestational weight gain (GWG) and noted a data gap on associations with long‐term outcomes, specifically child weight. Currently the mediating role of birthweight and heterogeneity by prepregnancy BMI are unclear. We used the nationally representative Early Childhood Longitudinal Study‐Birth Cohort to examine associations between GWG and subsequent child weight measured at 5 y. We used regression and path analysis to examine direct and indirect effects mediated by birthweight. Among underweight, normal, overweight and obese women, respectively, prevalence of excessive GWG (above recommendations) was 26%, 38%, 62% and 53%, and child obesity (BMI ≥ 95th percentile) was 9%, 13%, 19% and 27%. Multivariable logistic regression indicated null associations between inadequate GWG and child obesity for all prepregnancy BMI groups, but a significant association with excessive GWG among only normal [OR 1.8 (95% CI 1.3, 2.5)] and overweight [OR 2.0 (95% CI 1.1, 3.4)] women. Path analysis with child BMI z‐score further indicated that among normal and overweight women the direct effect of GWG was stronger than the indirect effect. Among obese women, there was no significant total effect of GWG. Our findings indicate that IOM GWG recommendations are appropriate in the context of child weight; prevention of excessive GWG may be a strategy to prevent child obesity.Grant Funding Source: Oak Ridge Institute for Science and Education (ORISE)
Plasma alpha‐tocopherol transport studied using deuterium‐labeled collard greens
Authors: Traber Maret G , Leonard Scott W , Fu Xueyan , Grusak Michael A , Booth Sarah 
Published: June 2021

To evaluate the bioavailability and plasma transport of deuterium‐labeled (d)‐alpha‐tocopherol (aT) from food, we used collard greens grown in deuterated water as a source of d‐aT. A single serving of 120 g steamed d‐collard greens (1.2 ± 0.1 mg d‐aT) was eaten by each of 20 healthy adults with a standard breakfast; blood samples were obtained up to 72 h. Plasma aT concentrations were measured using LC/MS in negative mode; the ion abundances of d‐aT and unlabeled aT were determined using selected ion monitoring to detect d‐aT isotopomers; predominant ones were m/z 438–442. The (m/z 438–442)/(m/z 434–446) ratio was 0.63 in collard greens, which was used to correct the plasma d‐aT abundance. Peak plasma d‐aT concentrations (250 ± 130 nmol/L; 1.2% ± 0.6% total a‐T) occurred at 9 to 16 h with an estimated absorption of ~36%. The post‐peak exponential disappearance rate was 0.6 ± 0.2 pools/d, equivalent to a half‐life of 29 ± 8 h. This is the first time that aT bioavailability from food with naturally incorporated d‐aT has been measured. Our findings confirm the relatively limited absorption and slow plasma disappearance of physiologic d‐aT doses.Grant Funding Source : USDA No. 58‐1950‐7‐707, USDA No. 58‐6250‐6‐003, NIH DK081761, NIH DK069341
Whole grain intake is associated with inflammatory markers in the Framingham Offspring Study
Authors: McKeown Nicola Mary , Ma YiYi , Rogers Gail , Meigs James , Fontes João , Jacques Paul 
Published: June 2021

Inflammation is a recognized risk factor for type 2 diabetes (T2D) and cardiovascular disease (CVD). Intake of whole grains is inversely associated with risk of T2D and CVD, and reduced inflammation may be an important mediator in this relationship. We examined the cross‐sectional associations of whole grain intake and markers of inflammation in 1674 participants of the Framingham Offspring Study. Whole grain intake (g/d) was estimated by FFQ and calculated with and without added bran and germ. With the exception of C‐reactive protein (CRP), no sex interactions were observed between whole‐grain intake and markers of inflammation. After adjusting for age, sex, abdominal adiposity, energy intake, current smoking, alcohol intake, dietary fat, multivitamin use, aspirin use, and non‐steroid drug use, intake of whole grains with and without inclusion of added bran and germ was inversely associated with CRP, interleukin 6 (IL‐6), and monocyte chemoattractant protein (MCP‐1). Compared with participants in the lowest quintile category of energy‐adjusted whole‐grain intake, participants in the highest quintile category had 6% and 12% lower concentrations of MCP‐1 (p‐trend <0.001) and IL‐6 (p‐trend=0.05). The concentration of CRP was 23% lower in the highest quintile of whole‐grain intake in men only. Whole‐grain intake was not associated with tumor necrosis factor‐alpha. These findings suggest that inflammation is lower among those consuming on average 3 or more daily servings of whole grains.Supported in part by grants from USDA ARS (contract number 58‐1950‐7‐707.); NHLBI (contract number NO1‐HC‐25195); RO1 HL64753; R01 HL076784; R01 AG028321; General Mills Bell Institute of Health and Nutrition
Changes in micro‐architectural characteristics of mandibular sutures using micro‐CT images in American Alligators during ontogeny
Authors: Zapata Uriel , Liu Sean , Sun Jun , Elsey Ruth M. , Wang Qian 
Published: June 2021

It has been well‐established that sutures in the skull play two main roles: they are associated with early stages of ontogeny allowing the brain growth, and they are not only affected but also influenced by their biomechanical environments during ontogeny. However, questions regarding how the microstructure of the sutures changes with growth and biomechanical environments have not been systematically studied. We hypothesized that, [1] the microstructure of sutural tissue changed during ontogeny, and [2] there were sex‐based difference in the change during ontogeny. Bone volume (BV), tissue volume (TV), bone surface (BS), structural density (BV/TV), and degree of anisotropy were evaluated by using micro‐CT technique in thirty sutures between the surangular and the dentary bones of the mandible of the American alligator (Alligator mississippiensis). Specimens were removed from 15 subject (8 males and 7 females) covering three ontogenetic groups: [1] juvenile from 12–36 in. long, [2] junior adult from 37–72 in. long, and [3] senior adult from 73–96 in. long. Results demonstrated that there were no significant difference between male and female animals. However, there were significant differences in BV/TV between specimens from the senior adult groups and specimens from younger age groups (p<0.05). In conclusion, mineralization processes in mandibular sutures increase during ontogeny, suggesting changes in mechanical properties that could affect sutural function.Grant Funding Source: Supported by NSF BCS‐0725183, and COLCIENCIAS (Bogotá, Colombia)
Creating Effective University‐K12 Outreach Partnerships
Authors: Mills David 
Published: June 2021

Through collaboration with university research faculty and local K‐12 school systems, Louisiana Tech University's (LA Tech) ‘Creating Connections’ program is integrating molecular science and nanotechnology into the K‐12 curriculum. Specifically, the Creating Connections Program goals are to: (1) establish hands‐on science laboratories in partner schools, (2) provide professional development and increased content knowledge for partner teachers, and (3) provide teachers (and their students) with authentic research and scientific experiences. In the summer, teachers participate in selected professional development programs designed as a hands‐on, inquiry‐based experience to introduce LA Tech research into the K12 classroom. Through a series of academic year workshops, partner teachers, in conjunction with LA Tech research faculty, generate lab modules tailored to the grade‐specific curriculum. In addition to their involvement in research, the professional development component of the program provides an introduction to equipment used for nanoscale research, data interpretation and analysis, and how to ‘critique’ the scientific literature. Teachers develop and implement, a classroom‐learning module integrates their nanoscience research experience into the K12 curriculum.Grant Funding Source : National Science Foundation, Shell
The Effects of Citrate on Glyoxasomal Malate Dehydrogenase
Authors: Mays Jacqunae , Marion James , Bell Ellis 
Published: June 2021

Malate Dehydrogenase plays critical roles in the cytosol, the mitochondrion and in plants also in glyoxysomes. Mitochondrial and gyloxysomal forms of malate dehydrogenase are thought to be subject to allosteric regulation by citrate. To explore the mechanisms of citrate effects on the enzyme we have used a combination of initial rate kinetics, site directed mutagenesis, circular dichroism (in conjunction with thermal melts) to follow effects on secondary and tertiary structure, dynamic light scattering to follow effects on quaternary structure and limited proteolysis to explore local flexibility/accessibility changes. Citrate, which binds to only one of the two otherwise identical active sites, is a partial inhibitor under all circumstances examined (varied pH, forward or reverse reaction), has no effect on the quaternary structure of the protein but induces changes in local flexibility/accessibility in a loop near the subunit interface. Several mutations at the subunit interface (V195A, L269A, E256Q, H90Q)also impact citrate inhibition. Together these results suggest that citrate exerts its effects on activity by binding to the “empty” active site in a reciprocating subunit mechanism, eliciting altered subunit interactions that contribute to overall catalysis.This work is supported by NSF Grant MCB 0448905 to EB
The Linkage Between Citrate, pH Regulation and Protein Folding in Glyoxysomal Malate Dehydrogenase
Authors: Yanta Helen , Bell Ellis 
Published: June 2021

Malate Dehydrogenase, a dimeric enzyme that catalyzes the NAD/NADH‐dependent reversible oxidation of malate into oxaloacetate, is involved in the Citric Acid and Glyoxylate Cycles as well as the malate‐aspartate shuttle. Citrate and pH appear to regulate the activity of glyoxysomal and mitochondrial MDH. The aim of this project is to study the linkage between pH and citrate regulation of Malate Dehydrogenase and protein stability and folding cooperativity. Over the pH range from 6.0 to 8.0 clear effects on secondary structure as shown by circular dichroism are seen. Thermal melts using CD at 222nm with data fitting via a four parameter Hill equation to give both Tm and a cooperativity parameter indicate effects on the unfolding cooperativity as well as the overall stability. Likewise, Citrate binding at various pH values clearly affects both, suggesting a linkage between secondary and tertiary structure stabilities, allosteric behavior and folding cooperativity.This work is supported by NSF Grant MCB 0448905 to EB.
The Roles of Conserved Cysteine Residues in the Structure and Function of Glyoxysomal Malate Dehydrogenase
Authors: Jones Rachel , Bell Ellis 
Published: June 2021

Bioinformatics analysis of malate dehydrogenases from both eukaryotic and prokaryotic sources indicate the existence of a number of cysteine residues that are highly conserved in mitochondrial and glyoxysomal forms of the enzyme (C282 and C295) as well as a cluster of cysteines (145, 151, 152) that are not conserved. In order to probe the roles of these conserved cysteines residues in both structure and folding of the enzyme as well as the catalytic activity, a number of site directed mutants (C145V‐C151S‐C152S triple mutant, C282S and L, and C295S) of watermelon glyoxysomal malate dehydrogenase have been constructed, expressed, purified and characterized. The resultant mutants are characterized for reactivity to DTNB (native protein reacts slowly indicating that one or more of the SH groups are somewhat accessible), secondary and tertiary structure using CD and CD/Thermal melts, and catalytic activity. Preliminary results indicate that all mutants have significant activity with differences in Km and Vmax. Similarly all mutants show evidence via CD for secondary structure but show some differences in stability and cooperativity of folding suggesting that none of the conserved cysteines are critical for activity but contribute to overall structure and function.This work is supported by NSF Grant MCB 0448905 to EB
Structural investigations of ClC‐ec1, a large integral membrane protein, using solution‐state NMR and nanodisc technology
Authors: Chew Thomas , Abraham Sherwin , Elvington Shelley , Maduke Merritt 
Published: June 2021

CLC antiporters mediate Cl−/H+ exchange across cell membranes in organisms ranging from E. coli to humans via coupling of protein conformational changes to ion binding, unbinding and translocation. X‐ray crystallographic structures have provided essential molecular pictures, but details of conformational changes remain elusive. We are using solution state NMR to probe conformational change in ClC‐ec1, a CLC homolog of known structure. 13C labeling of lysine residues is achieved by post translational reductive methylation. 1H‐13C HSQC spectra reveal reversible, substrate‐dependent spectral changes that may reflect conformational changes. To address the concern that the detergent‐solubilized protein is not in a native environment, we are also using nanodiscs, which consist of two amphipathic helices wrapped around a bilayer patch of lipids surrounding the membrane‐embedded protein. The monomeric, 13C‐methylated mutant form of ClC‐ec1 was incorporated into discs and tested for homogeneity and monodispersity. The 1H‐13C HSQC spectra show substrate‐dependent spectral changes in this system, although further experiments will be needed to determine if these represent functionally‐relevant conformational changes. These studies demonstrate the potential for using solution‐state NMR and nanodisc technology to study ClC‐ec1 in a native lipid environment.Supported by: National Science Foundation
A food based intervention for drug‐naïve HIV+ women living in Turbo, Kenya
Authors: Ettyang Grace , Neumann Charlotte , Siika Abraham , Nyandiko Winstone , Ernst Judith 
Published: June 2021

ObjectiveTo determine the contribution of a food intervention to nutrient intakes.MethodsDuring 2008–2010, 225 drug naïve HIV+ (WHO Stage 1 or 2; CD4 >250), 19–45 yrs, clients at the USAID‐Academic Model Providing Access to Healthcare (AMPATH) clinic at Turbo enrolled in a randomized trial of beef vs soy vs wheat biscuit supplements. Height and weight were obtained with standardized procedures. Dietary patterns were summarized from food questionnaires. Nutrient intakes were determined with customized computer soft ware. The adequacies of nutrient intakes were determined with the probability approach and estimated average requirement (EAR).ResultsAt baseline, the women mean (±SD) age, body mass index and CD4 were 36.4(7.5) yrs, 22.3(3.6) and 492(191) cells/μL, respectively. Inadequate intakes of 100% occurred for iron, zinc and vit. A. Biscuits were well tolerated and those with beef provided vit. A, selenium, zinc, and vit. B12 at 22%, 24%, 37% and 50% of EAR respectively; soy biscuit provided selenium > EAR.ConclusionsThe beef biscuit provided drug naïve HIV+ Kenyan women micronutrients, whose deficiencies are linked to HIV disease progression. Improved nutrition status and slowed disease progression are expected outcomes from this feeding trial which is near completion. Supported in part by USAID Grant No. PCE‐G‐ 00‐98‐00036‐00, 1R01HD57646‐01A1 (CFDA #93.865) and Heifer Project International.
Web delivered program to demonstrate a pedagogy promoting meaningful learning
Authors: Modell Harold I. , Michael Joel A. , Knoche Craig 
Published: June 2021

Meaningful learning results when acquired information is used to accomplish a goal or solve a problem. Meaningful learning is an iterative process in which the learner (1) recognizes his/her existing mental model, (2) tests the mental model, and (3) refines the mental model. Helping the learner to engage in this process requires a pedagogy in which the instructor assesses the current knowledge of the learner, presents him/her with opportunities to apply this knowledge (e.g. make a prediction), and helps the learner refine his/her mental model before making another prediction. We have developed a web delivered computer program that helps students study mechanisms underlying pressure and volume changes occurring during a cardiac cycle. The program engages the student in a dialog that explores common misconceptions related to the cardiac cycle and helps her/him generate a Wiggers diagram. In an assessment component of the program, the student predicts the nature and site of valve pathophysiology given a Wiggers diagram or predicts the Wiggers diagram resulting from a specific valve pathophysiology. The student is able to test these hypotheses using a simulation of the cardiovascular system.Supported in part by NSF Grant #DUE‐1043422.
Comparative analysis of masticatory apparatus features in neonatal common marmosets (Callithrix jacchus) and cotton‐top tamarins (Saguinus oedipus)
Authors: Mork Amy Lovejoy , Taylor Andrea B , Vinyard Christopher J 
Published: June 2021

Marmosets are unique among callitrichids in habitually gouging trees with their anterior teeth to stimulate exudate flow. Previous analyses suggest that the masticatory apparatus of adult marmosets displays features facilitating relatively large jaw gapes, but decreased load‐resistance ability relative to closely‐related non‐gouging tamarins. We analyzed masticatory apparatus features of neonatal marmosets and tamarins to determine if the morphological differences observed between adults are present at birth. If marmoset infants show similar morphological divergence as adults, then the early appearance of these features suggest they are potential adaptations for tree gouging at wide gapes.We examined six stillborn common marmosets (Callithrix jacchus) and six cotton‐top tamarins (Saguinus oedipus). We microCT scanned the jaws, quantified fiber architecture of masticatory muscles and estimated symphyseal strength in simulated in vitro loading.We found few differences in mandibular cross‐sectional geometry, symphyseal strength or jaw‐muscle architecture between marmoset and tamarin neonates. Collectively, these findings suggest that at least some of the postnatal changes in the marmoset mandible and jaw‐muscle architecture that facilitate wide gapes, but reduced load‐resisting abilities compared to tamarins, arise from phenotypic plasticity related to gouging at wide gapes.Grant Funding Source: This work was funded by grants from the National Science Foundation (BCS‐0959438; BCS‐0412153).
The Role of Vascular Endothelial Growth Factor in Mechanically Stimulated Muscle Derived Stem Cell Repair
Authors: Beckman Sarah , Mlakar Logan , Huard Johnny 
Published: June 2021

We have previously shown that muscle‐derived stem cells (MDSCs) are significantly better than myoblasts at maintaining cardiac function after infarction, which is likely due to higher survival and vascular endothelial growth factor (VEGF) secretion. Mechanical stimulation increases VEGF secretion, and after mechanically preconditioning MDSCs and injecting them into an acute model of cardiac infarction function is improved. Therefore, we hypothesized that the benefits seen from mechanical stimulation is due to an increase in VEGF, and if we block VEGF we will not see an improvement in repair. To test this we have mechanically stimulated MDSCs transduced with the soluble VEGF receptor antagonist sFlt1 and tested their regenerative potential in the skeletal muscle of a mouse model of Duchene Muscular Dystrophy. We have found that mechanically stimulating MDSCs resulted in an increase in angiogenesis in the engraftment area. The MDSCs transduced with sFlt1 resulted in less angiogenesis, and the mechanically stimulated MDSCs transduced with sFlt1 showed no difference in angiogenesis from the un‐stimulated sFlt1 group. There also appears to be little difference between fibrosis in the sFlt1 stimulated and un‐stimulated groups. Therefore, VEGF appears to be a critical factor in angiogenesis following cell transplantation in mechanically stimulated MDSCs.Grant Funding Source : DOD
Expression and auto‐processing of hedgehog‐like proteins from Brugia malayi
Authors: Savidis George , Drago Matthew J. , Reitter Julie N. , Mills Kenneth V. 
Published: June 2021

Hedgehog proteins have an N‐terminal signaling domain and a C‐terminal auto‐processing domain, called the HINT domain (for Hedgehog‐INTein, as it shares sequence and structural similarities to self‐splicing inteins). The HINT domain has a C‐terminal sterol‐recognition region (SRR) not shared with inteins. We will analyze the post‐translational cleavage between the signaling and HINT domains from a hedgehog‐like protein from the parasitic nematode Brugia malayi. We have created E. coli expression vectors that encode fusion proteins of 1) an N‐terminal maltose‐binding protein to the HINT domain, or 2) an N‐terminal His‐tag to the signaling and HINT domains. We have created both fusion proteins with and without the SRR. We are currently optimizing expression and purification conditions for these proteins, with the aim to study the role of conserved intein residues in the hedgehog‐processing mechanism.This material is based upon work supported by the National Science Foundation under grant MCB‐0950245, the Camille and Henry Dreyfus Foundation (KVM), and a Sherman Fairchild Foundation Summer Research Scholarship (GS).
Side‐chain cyclization of Gln or Asn residues coupled to peptide bond cleavage in an intein and a model peptide
Authors: Urbanski Laura M. , Chin Stacy L. , Reitter Julie N. , Mills Kenneth V. 
Published: June 2021

Protein splicing is a post‐translational event by which an intervening polypeptide, or intein, facilitates its own excision from the flanking polypeptides, or exteins, and the ligation of the exteins. An epimerase found in Trichodesmium erythraeum contains two inteins, Ndse1 and Ndse2. The first intein, Ndse1, can facilitate protein splicing efficiently in E. coli, even with a native C‐terminal Gln replacing the highly conserved Asn. In addition, activity of the intein may be influenced two downstream Cys residues and the presence of disulfide bonds, as we observed differential reactivity in inteins expressed under reducing and non‐reducing conditions. Substitution of Gln for Asn results in an increase in the rate of C‐terminal bond cleavage for the PolII intein from Pyrococcus abyssi. To study side chain cyclization in a model system, we obtained three pentapeptides of Abz‐His‐Xxx‐ Src‐Lys, where Xxx is Gln, Asn or Ala. Dnp, dinitrophenyl, is attached to the C‐terminal Lys and ortho‐aminobenzoic acid (Abz) serves as the N‐terminal residue. Peptide bond cleavage separates the Abz fluorophore from the Dnp quencher.This material is based upon work supported by the National Science Foundation under grant MCB‐0950245, the Camille and Henry Dreyfus Foundation (KM), and a Holy Cross Alumni/Parents Summer Research Scholarship (LU).