bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure‐Function Studies of the ADPGlucose Pyrophosphorylase from Agrobacterium tumefaciens: Defining the Roles of the K310 and P288 Residues in Allosteric Regulation
Authors: Duong Vanessa , Butz John , Nguyen Tuong , Ochoa Jackie , Meyer Christopher R 
Published: June 2021

ADP‐glucose pyrophosphorylase (ADPG PPase, EC 2.7.7.27) is the enzyme that catalyzes the rate limiting step in the glucan biosynthesis pathway. By identifying important residues of the protein a more active enzyme may be engineered thus yielding more renewable carbon. Agrobacterium tumefaciens (Ag. t) ADPG PPase is activated by fructose‐6‐phosphate (F6P) and pyruvate and is inhibited by inorganic phosphate and sulfate. It is believed these effectors bind at a common allosteric site. Based on previous experiments it is believed the P288 residue, which is part of the loop region connecting the N‐terminus domain to the C‐terminus domain, is involved in allosteric regulation. The P288D mutant displayed higher activity than the wild‐type (WT) in the absence of activators and it displayed desensitization to effectors. Molecular modeling suggests reveals the K310 residue could potentially be forming a salt bridge with the aspartate residue at the substituted P288 site. It had been previously shown that the K310A enzyme displayed very low activity that was similar to WT in its response to activators; the K301A enzyme activity was increased by the presence of the P288D mutation which also desensitized the enzyme to effectors. To further probe the roles of these two residues with respect to charge and size, the K310Q, K310R, P288D/K310Q and P288D/K310R were successfully generated. The altered proteins were generated by site‐directed mutagenesis (QuikChange Kit, Stratagene) and expressed in E.coli glgC− cells. The K310Q and K310R mutants were successfully generated and purified using Phenyl Sepharose, Diethylaminoethanol, and Cibracon Blue chromatography. Substitution of the P288 residue resulted in changes in allosteric behavior with the largest effects being desensitization to activators. Preliminary studies on the crude extract of the K310Q and K310R mutants show a 2.85 and 17.46 fold increase activity compared to the WT, respectively, indicating the importance of shape and charge for optimal activity. For the each double mutation the activity was diminished, for P288D/K310Q and P288D/K310R, a 6.5 and 1.6 fold decrease in activity compared to WT, respectively. Complete kinetic and structural characterization of the single and double mutant enzymes will allow for a comprehensive comparison to the WT enzyme and a more detailed understanding of structure‐function relationships.Support or Funding InformationSupported in part by NSF and NSF BIO MCB grant #0448676.
Endothelial function assessment in nutritional research studies: a comparison of two arterial occlusion sites for assessing reactive hyperemia using a peripheral arterial tonometry device
Authors: Woodhouse Leslie R , Adkins Yuriko , Bonnel Ellen , Peerson Janet M 
Published: June 2021

Endothelial function assessment can be an important tool in evaluating artery health in humans, and can be an important phenotyping tool in nutritional research studies as well as an early indicator of cardiovascular disease. We conducted a study of endothelial function in healthy adults using reactive hyperemia peripheral arterial tonometry (RH‐PAT) by the EndoPAT™ device (Itamar Medical Ltd., Caesarea, Israel) in order to compare two arterial occlusion sites. Brachial artery (upper arm) occlusion is the most common occlusion site, yet a forearm occlusion site may be a potentially valid site for endothelial function testing. RH‐PAT testing is an operator independent, non‐invasive technique that measures the arterial pulse wave amplitude using pneumatic fingertip probes during reactive hyperemia allowing a RH‐PAT index (RHI) to be calculated. Reactive hyperemia was achieved by occluding either the upper arm (brachial artery) or the forearm (ulnar and radial arteries) in the individual using a blood pressure cuff inflated to ~200 mmHg for 5 minutes. Twenty healthy adults (14 female, 6 male), age 38 ± 12 years (mean ± SD) and BMI 24 ± 3 kg/m2 participated in the study. RH‐PAT measurements were determined in the morning after a 12 hour fast. Participants were tested approximately 3 days apart using a crossover design with randomization of upper arm and forearm as occlusion sites. The participant's non‐dominant arm was always the occluded arm. Participants were tested in a quiet, temperature‐controlled (21–24°C) room in a supine position for at least 15 minutes prior to the 15 minute test: 5 minute baseline, 5 minute occlusion, and 5 minute post‐occlusion. A self‐reported numeric pain intensity scale (0–10) was used to evaluate pain during the occlusion and post‐occlusion (hyperemic period) portion of the measurement. The RHI is the post‐to‐pre occlusion PAT signal ratio in the occluded arm, relative to the same ratio in the control arm, corrected for baseline vascular tone of the occluded arm. The mean RHI for the two occlusion sites: 2.15 ± 0.78 (upper arm) and 2.36 ± 0.75 (forearm) was not different (p=0.18, paired t‐test). A Pearson correlation of the RHI from both sites (r=0.602, p=0.005) was positive and significant. The mean reported pain intensity for the upper arm was 3.7 ± 1.3 compared to 2.7 ± 1.8 for the forearm; these indices were significantly different (p=0.002, signed‐rank test). In summary, occlusion of the forearm appears to be a potentially valid alternate occlusion site for RH‐PAT measurement and is less painful than using the upper arm as an occlusion site. In addition, the occlusion site should be standardized in the study protocol. Human study approved by the UC Davis Institutional Review Board.Support or Funding InformationUSDA, ARS Projects: 2032‐51000‐022; 203253000‐001
Long‐term Intermittent Leucine Pulses during Continuous Feeding Impact the Plasma Metabolome of Neonatal Pigs
Authors: Suryawan Agus , Boutry Claire , Manjarín Rodrigo , El‐Kadi Samer W. , Steinhoff‐Wagner Julia , Nguyen Hanh , Fiorotto Marta L. , Davis Teresa A. 
Published: June 2021

Infants who are unable to maintain oral feeding can be nourished by continuous administration of feed via orogastric tube. We have shown in a neonatal piglet model that intermittent pulses of leucine administered during continuous feeding enhanceslean tissue growth compared to continuous feeding alone. This response was consistent with the attainment of higher rates of muscle protein synthesis in the leucine supplemented piglets. To determine the long‐term effects of intermittent leucine pulses on metabolomic markers in the plasma of neonates, piglets (n = 23, 7‐d‐old) were fed continuously a milk replacement formula via orogastric tube for 21 d with an additional parenteral infusion of either a leucine (800 μmol·kg−1·h−1, CON+LEU)or alanine (CON+ALA) supplement for 1 h every 4 h; blood samples were collected at d 21. Plasma samples were analyzed by Metabolon (Durham, NC, USA) using GC‐MS and LC‐MS. There were 483 compounds identified in the analysis matching known chemical structures. Following log transformation and imputation of missing values, Welch's two‐sample t‐test was used to identify metabolites that differed significantly between experimental groups. The results showed that in the CON+LEU compared to the CON+ALA group, the BCAA‐related changes in metabolites was consistent with increased leucine metabolism. Concentrations of leucine‐containing dipeptides, an indicator of protein synthesis, were elevated in the CON+LEU group compared to the CON+ALA group (P < 0.05). Concentrations of dimethyl arginine, a marker of proteolysis, were reduced in CON+LEU compared to CON+ALA group (P <0.05). These results are consistent with the observed differences in the growth responses to the two treatments. Altogether, these data support the notion that, in addition to increasing protein synthesis, leucine supplementation ameliorates muscle protein degradation, and therefore may be useful as atherapeutic agent to promote growth in neonates. Thus, plasma metabolomics profiling may be a useful tool to identify biomarkers of protein synthesis and degradation pathways that are modulated by leucine supplementation in neonates.Support or Funding InformationNIH AR444474, NIH HD072891, USDA NIFA 2013‐67015‐20438, and USDA/ARS 6250‐51000‐055
Native African Plant Materials Modify in vitro Bioaccessibility of Provitamin A Carotenoids from Blended Cereal Products
Authors: Debelo Hawi , Ndiaye Cheikh , Ferruzzi Mario , Hamaker Bruce 
Published: June 2021

Native plant materials can play an important role in addressing deficiency of key shortfall micronutrients including vitamin A (VA), iron (Fe) and zinc (Zn) in Sub‐Saharan Africa. However, information on the micronutrient composition of these plants and strategies for their incorporation into viable consumer products is scarce. In particular, limited information is available on the interaction of materials on the bioavailability of key nutrients such as proVA carotenoids. In the current study, 28 distinct plants and traditional cereal grains (millet and sorghum) from Senegal and Niger were characterized for their carotenoid and mineral content. Among the plant materials analyzed, Adansonia digitata (Baobab), Moringa oleifera (Moringa), and Hibiscus sabdariffa (Hibiscus) were identified as potential sources of key shortfall nutrients, Fe (54.5–237.2 μg/g) and Zn (4.2 – 72.38 μg/g). Dried carrot and mango materials common to West Africa were identified as provitamin A sources. Following initial screening, plant materials were formulated in model instant cereal based porridges designed to mimic thin porridge products common to West Africa. Proportions of instant cereal and plant materials were dry blended to deliver ~25% of the RDA for proVA, Fe and Zn as follows: extruded cereal based flour (45–65%), dried proVA rich plants (30% as carrot and mango) and dried mineral rich plants (0–25% as Hibiscus, Moringa or Baobab). Porridges were reconstituted with hot water (100°C), 5% oil was then added and the final product was introduced to an in vitro digestion model to assess the impact of mineral rich plant materials and grain background on the bioaccessibility of proVA carotenoids. Baobab inclusion was found to significantly increase (p<0.05) bioaccessibility of total proVA (TPVA) carotenoids from 18.26±1.8% to 31.68±4.1% (mean ± SEM) in dose‐dependent manner from 5% to 25% baobab. Conversely, carotenoid bioaccessibility was reduced with increased amount of Moringa and Hibiscus. Interestingly, Baobab at 5% had the lowest (p<0.05) digestive recovery of TPVA carotenoids (24.86 ± 5.96%) whereas Hibiscus at 5% had the highest recovery (55.35 ± 2%) suggesting that interactions between plant materials may impact both digestive stability and micellarization of proVA carotenoids. Based on bioaccessible proVA content of digested porridges, 200g of porridge with baobab formulated at 25% of dry mix) would provide 30% of the vitamin A EAR for children 1–3 years old. These results suggest that native plant materials selected to enhance mineral content may also promote interactions that can impact availability of proVA carotenoids in finished products.Support or Funding InformationThis research was supported by USAID Food Processing Innovation Lab (AID‐0AA‐L‐14‐00003).
Activation of ubiquitin‐proteasome system components in heat‐stressed pig skeletal muscle
Authors: Zhao Lidan D , Zhang Zhenhe , Xie Guohao , Selsby Joshua T , Baumgard Lance H , Rhoads Robert P 
Published: June 2021

Hyperthermia causes metabolic changes and leads to lower lean tissue accretion and increased adipose tissue deposition in animals. The direct effect of heat stress on muscle breakdown has been reported in poultry, rabbits and lactating cows. Muscle breakdown occurs by activating the ubiquitin‐proteasome system and the autophagy‐lysosome pathways. To study the mechanism by which heat stress induces muscle breakdown, the ubiquitin‐protease system in the pig skeletal muscle was examined. Pigs (35 ± 0.8 kg) were assigned to one of three treatments: thermal neutral fed ad libitum (TN, 21°C, n=8), heat stress fed ad libitum (HS, 35°C, n=8), or thermal neutral, pair‐fed to HS intake (PF, n=8) for 7 days. Longissimus dorsi muscle was biopsied on day 3 and 7 relative to start of treatments for real‐time PCR and immunoblotting assays. Heat stress increased activating transcription factor‐4 (ATF4), a stress‐response transcription factor, mRNA abundance by more than 1.5 fold regardless of days (P < 0.05). Heat stress increased growth arrest and DNA damage‐inducible 45a (Gadd45a) mRNA abundance by about 1.5 fold compared with PF muscle (P < 0.05). Similarly, the protein abundance of skeletal muscle Gadd45a was elevated in HS pigs by 50% as well as in PF pigs compared with TN pigs (P < 0.05). The phosphorylation of GSK3 β was similar between groups on day 3 and not different in HS versus PF and TN muscle. However, PF pigs had significantly higher phosphorylated GSK3β compared with TN pigs (P < 0.05). HS pigs exhibited intermediate atrogin‐1 mRNA abundance, which was not different from either TN or PF pigs. However, HS pigs had a significantly higher muscle ring finger‐1 (MuRF1) mRNA abundance (approximately 2 fold) compared with PF pigs (P < 0.05). In conclusion, heat stress activated components of muscle breakdown by inducing AFT4, which increased Gadd45a expression, and subsequent apparent activation of the ubiquitin‐protease system.Support or Funding InformationResults described herein were supported by Agriculture and Food Research Initiative Competitive Grant nos. 2011‐6700330007 and 2014‐67015‐21627 from the USDA National Institute of Food and Agriculture.
Bioaccessibility of Vitamin D from Bread Fortified with UV‐Treated Yeast is Lower than Bread Fortified with Crystalline Vitamin D2 and Bovine Milk
Authors: Lipkie Tristan E , Ferruzzi Mario , Weaver Connie M 
Published: June 2021

UV‐treated yeast may be used as a vitamin D fortificant in bakery products, yet the vitamin D status of rats fed bread fortified with vitamin D2 enhanced yeast was lower than those fed a diet with crystalline vitamin D3. The purpose of this study was to determine whether the digestive release and micellarization (bioaccessibility) of vitamin D from yeast might be a limiting factor. White wheat and whole wheat bread fortified with vitamin D2‐enhanced yeast or crystalline vitamin D2 and vitamin D3 fortified bovine milks (skim, 2%, and whole) were subject to in vitro digestion, and analyzed by HPLC‐MS. Bioaccessibility was greater (p<0.05) from bovine milks (70–85%) than from breads fortified with vitamin D2 enhanced yeast (6.0–7.5%). Bioaccessibility was about 4× greater from breads fortified with crystalline vitamin D2 than those with vitamin D2 enriched yeast. Presence of intact yeast cells after simulated gastric and upper intestinal digestion suggests that vitamin D may be entrapped within yeast cell membranes. These data suggest that low digestive release of vitamin D from yeast may partly explain the low apparent bioavailability as compared to crystalline vitamin D2 and D3 and additional processing may be required to enhance the digestive release of vitamin D from yeast.Support or Funding InformationSupport provided by Purdue University and the USDA National Needs Fellowship Program.
Plasma Biomarkers Of Glycocalyx Shedding After Hemorrhage And Resuscitation: Correlation With Microvascular Events
Authors: Filho Ivo Torres , Torres Luciana N , Salgado Christi , Valdez Celina , Dubick Michael A 
Published: June 2021

The microvascular endothelial glycocalyx plays an essential role in several physiological functions but can be damaged after hemorrhage and fluid resuscitation. Many studies report plasma levels of syndecan‐1 and heparansulfate as indirect markers of glycocalyx degradation. However, it is unknown how much these measures are representative of the changes occurring at microvascular level. To fill this void, we studied quantitatively the relationship between plasma biomarkers and changes in various microvascular parameters, including glycocalyx thickness, using hemorrhage and a wide range of resuscitation fluids. Rats were bled 40% of estimated total blood volume and resuscitated with different fluids(fresh whole blood, packed red blood cells:lactated Ringer's, fresh frozen plasma, 5% albumin, lactated Ringer's, 3% hypertonic sodium chloride solution, and normal saline). Control animal groups were either not hemorrhaged or not resuscitated. Intravital fluorescence video microscopy was used to estimate glycocalyx thickness and permeability in 270 post‐capillary venules from 58 cremaster preparations in 9 animal groups while other microvascular parameters were measured using non‐invasive techniques. Systemic physiological parameters and blood chemistry were simultaneously collected. In hemorrhaged rats, mean arterial pressure decreased from 100 ± 2 mmHg to 50 ± 3 mmHg after bleeding, and remained at intensities significantly lower than baseline after resuscitation. Exposure of animals to hemorrhage and different resuscitation fluids resulted in various glycocalyx degradation levels as expressed by different levels of glycocalyx thickness and plasma concentrations of syndecan‐1 and heparan sulfate. Glycocalyx thickness changes were correlated with plasma level changes of syndecan‐1 (r = −0.9, p<0.01) and heparansulfate (r = −0.9, p<0.01). Microvascular permeability changes were correlated with changes in both plasma biomarkers (r = 0.7, p<0.05). Syndecan‐1 and heparan sulfate were also correlated (r = 0.7, p<0.05). Except for diameter and permeability, changes in microvascular parameters (red blood cell velocity, blood flow, wall shear rate) did not correlate with plasma biomarkers or glycocalyx thickness changes. Concurrent measurements of microvascular parameters, glycocalyx thickness and levels of plasma biomarkers, coupled with evaluation of systemic parameters, allowed a comprehensive evaluation of glycocalyx degradation after hemorrhage and resuscitation. The quantitative framework provided here suggests that monitoring plasma biomarkers of glycocalyx shedding may be useful in guiding resuscitation strategies following hemorrhage.Support or Funding InformationSupported by US Army Medical Research & Materiel Command.
Stoichiometry of Novel Protein Modifications in Livers of Warm‐adapted Threespine Sticklebacks from Baja California (Mexico)
Authors: Levitan Bryn Bo , Gómez‐Jiménez Silvia , Li Johnathon , Kültz Dietmar 
Published: June 2021

The purpose of this study was to investigate molecular phenotypes that have enabled the survival of a species above its typical lethal temperature limit. A unique population of threespine sticklebacks (Gasterosteus aculeatus) from Baja California, Mexico are surviving and able to function normally at temperatures close to 30 degrees Celsius, a temperature that is higher than normal for this species. Understanding how this warm‐adapted population is able to function at high temperatures at the molecular level may give insight into the mechanisms that have allowed for their survival, and the potential for other populations to adapt to increasing temperatures due to global climate change. Livers from sticklebacks of this unique warm‐adapted population (Baja California, Mexico) were compared to those of a typical cold‐adapted population (Anchorage, Alaska) using gel‐free quantitative proteomics by liquid chromatography‐mass spectrometry (LC‐MS/MS) in order to identify post‐translational modifications (PTMs) in proteins involved in redox and detoxifying biochemical pathways. The stoichiometry of these proteins were then compared between the two populations. Nineteen novel PTMs were identified in 11 different redox proteins, with major differences in stoichiometry detected between the two populations for catalase, alcohol dehydrogenase 1, three glutathione‐s‐transferase isozymes, and carbonyl reductase [NADPH] 1. Further investigation into the functional significance of these PTMs has the potential to reveal novel mechanisms by which adaptation to high temperatures affects redox regulation and detoxification mechanisms. It is well known that adaptation to high temperature affects gene and protein sequences at evolutionary time‐scales and the expression of abundances of particular mRNAs and proteins. Our study provides evidence that specific covalent protein modifications also represent important targets of evolutionary selection during high temperature adaptation of fish. Such modifications result in modulation of protein structure and function leading to concomitant changes in molecular and higher‐order phenotypes that provide an apparent adaptive advantage at elevated habitat temperature.Support or Funding InformationThis work was supported by the National Science Foundation, IOB 1355098.
Obesity Prevention Intervention Recruitment and Implementation by Home Visitation Staff (HVS): Characteristics Associated with Success and Implications for Research Staff Training
Authors: Eck Kaitlyn , Byrd‐Bredbenner Carol 
Published: June 2021

HomeStyles is a childhood obesity prevention program disseminated to families with young children via home visitation staff (HVS) who are non‐nutrition professionals (NNPs), but received program‐related training. Little is known about HVS’ abilities to recruit and implement obesity prevention intervention research with high‐risk families. Thus, the purpose of this study was describe the demographic characteristics, attitudes towards weight‐related parenting practices, personality traits, and lifestyle characteristics of home visitation staff (HVS) who are non‐nutrition professionals (NNP) and compare those who successfully recruited families to participate in an obesity prevention intervention to those who did not with the goal of better targeting and tailoring NNP HVS childhood obesity training. HVS were surveyed to describe their characteristics, attitudes towards weight‐related parenting practices, and personality traits. Unpaired t‐tests indicated that HVS who recruited families had significantly (p<.05) more education (93% vs. 49% had baccalaureate degrees) and were younger (age=31.00±8.26SD vs 39.90±8.23SD) than HVS not recruiting families. Successful recruiters were significantly more culturally aware (4.31±0.45SD vs 3.97±0.55SD, 5‐point scale) and had greater needs for cognition (i.e., propensity for enjoying problem solving, (4.31±0.61SD vs. 3.56±0.78SD, 5‐point scale). Successful recruiters also had significantly higher disinhibited (2.22±0.59SD vs 1.92±0.61SD, 4‐point scale) and restraint (2.68±0.65SD vs 2.35±0.59SD, 4‐point scale) eating scores, indicating they were less able to self‐regulate intake and restricted intake to control weight. Attitudes toward weight‐related parenting practices also differed significantly; successful recruiters felt significantly more strongly that parents should not use food rewards (4.40±0.64SD vs 3.92±0.73SD, 5‐point scale), but supported non‐food rewards to get children to eat healthy foods (4.07±0.82SD vs 3.21±1.13SD, 5‐point scale). Findings suggest that to increase HVS recruiting success for childhood obesity prevention programs, staff training should build cultural awareness, align personal eating behaviors with obesity prevention best practices, and improve attitudes toward recommended child feeding practices.Support or Funding InformationUSDA NIFA #2011‐68001‐30170