bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat exposure causes a complex stress response in heat‐intolerant mice
Authors: Islam Aminul , Abraham Preetha , Hapner Christopher , Andrews-Shigaki Brian , Deuster Patricia , Chen Yifan
Published: June 2021

We investigated the association between heat‐induced stress responses and heat tolerance levels in mice. Thirty‐eight mice were assigned into control and three heat exposure groups ‐ tolerant (TOL), moderately tolerant (MT) and intolerant (INT), based on their thermal responses. Real‐time core temperature, blood pressure, and heart rate were assessed during heat exposure (120 min at 39.5°C) under conscious condition. Tissue samples were collected 18–22 hours following heat exposure. INT mice had significantly higher peak mean arterial pressure and heart rate than TOL mice during heat exposure. Plasma corticosterone levels were significantly higher in INT than control mice. No changes in plasma cytokines or markers of oxidative status were observed. INT mice showed significant increases in HSP72 and HSP90 protein and mRNA levels in liver, heart and gastrocnemius muscles compared to TOL and control mice. In contrast, INT mice had significantly lower HSF1 and glucocorticoid receptor protein and mRNA levels in these tissues than TOL and control mice. These results suggest that heat exposure causes an extensive stress response in mice with heat intolerance. Complex transcriptional and translational processes are involved in mediation of heat‐induced stress. (supported by ONR N0001411MP20025 and USUHS R091EH)
Resting sympathetic baroreflex sensitivity in subjects with low and high tolerance to simulated hemorrhage with lower body negative pressure
Authors: Hinojosa-Laborde Carmen , Ryan Kathy L , Rickards Caroline A , Convertino Victor A
Published: June 2021

Central hypovolemia elicited by hemorrhage or lower body negative pressure (LBNP) triggers autonomic reflexes to maintain organ perfusion; these reflexes fail with severe blood loss resulting in cardiovascular collapse. The ability to tolerate LBNP is variable and factors contributing to tolerance are unclear. We tested the hypothesis that resting sympathetic baroreflex sensitivity (BRS) is attenuated in subjects who have a low tolerance (LT) to LBNP. Muscle sympathetic nerve activity (MSNA) and diastolic arterial pressure (DAP) were recorded in 48 human subjects who subsequently underwent LBNP to presyncope. LT subjects reached presyncope prior to completing −60 mmHg LBNP, and high tolerant (HT) subjects experienced presyncope after −60 mmHg LBNP. BRS was assessed as the slope of the relationship between spontaneous fluctuations in DAP and MSNA during 5 min of supine rest. MSNA burst incidence/ DAP correlations were strong (r>0.5) in 36 subjects (LT: n= 8; HT: n=28), and BRS was not different between LT and HT (−1.91 ± 0.31 vs. −2.24 ± 0.22 bursts·(100 beats)−1·mmHg−1, p=0.45). MSNA total activity/ DAP correlations were strong (r>0.5) in 34 subjects (LT: n= 8; HT: n=26), and BRS was not different between LT and HT (−592 ± 69 vs. −666 ± 70 arbitrary units·(beats)−1·mmHg−1, p=0.58). We conclude that resting MSNA BRS does not influence tolerance to LBNP. Funded by the US Army Medical Research and Materiel Command.
Anti‐Phase Expression of the BK Channel (Kcnma1) Alters Circadian Locomotor Activity in Mice
Authors: Lai Michael , Wright Breanne , Whitt Joshua , Meredith Andrea
Published: June 2021

Circadian rhythmicity, driven by the suprachiasmatic nucleus (SCN) of the hypothalamus, is essential to the survival or fitness of all organisms. The BK Ca2+ and voltage‐activated K+ channel is expressed in a circadian manner in the SCN, peaking at night, and genetic deletion of the BK channel (Kcnma1−/−) disrupts circadian behavioral rhythms. To determine whether the nighttime‐phased expression pattern was essential for normal circadian rhythmicity, we analyzed wheel running activity of transgenic mice that expressed the BK channel opposite to its normal phase in the SCN (Per1:BKR207Q ). We predicted this alteration of BK phase by expression of one or two copies (1C, 2C) of the Per1:BKR207Q transgene, or one copy of Per1:BKR207Q with one deleted endogenous copy of Kcnma1 (1C; BK het) would disrupt circadian wheel rhythms. In contrast, 1C, 2C, and 1C; BK het mice all had relatively normal baseline circadian rhythms. However, 2C mice had a longer active interval compared to WT, suggesting that nighttime‐phased expression of the BK channel is important for restricting locomotor activity. Additionally, 2C mice had a larger light‐pulse induced phase delays, suggesting these mice were more sensitive to phase‐shifting stimuli than WT. A better understanding of the neural encoding of circadian rhythms may impact the treatment of sleep and other disorders of circadian rhythmicity.

This work was funded by an APS summer research fellowship to (B.N.W.) and NSF (IOS‐0956237) and NHLBI (R01HL102758) to A.L.M.
Skeletal muscle is a potential source of cytokines during heat stroke recovery in mice
Authors: Leon Lisa R , Eustis Heather L , Urso Maria L
Published: June 2021

Skeletal muscle (SM) produces cytokines in response to exercise, but its role in cytokine production during heat stroke (HS) recovery is unknown. Mice show hypothermia and fever during HS recovery and these core temperature (Tc) responses are associated with high plasma cytokine and soluble cytokine receptor levels. We hypothesized that SM is a source of these proteins during mouse HS recovery. Gene expression of cytokines (IL‐1β, IL‐6, IL‐10, TNFα), cytokine receptors (gp130, IL‐6R) and TNFα converting enzyme (ADAM17) was measured in C57BL/6J mouse quadriceps at HS collapse (Tc,Max=42.7°C), hypothermia (HYPO; 29.3±0.4°C) and fever (24h; 37.8±0.3°C). HSP‐72 and ‐27 expression increased at Tc,Max, peaked at HYPO (217‐ and 40‐fold) and was elevated above controls at 24h (4‐ and 9‐fold). IL‐6 and IL‐10 expression increased ~4‐fold at HYPO with ~4‐fold decrease below controls by 24h. ADAM17 expression was ~6‐fold lower than controls at 24h. IL‐1β, TNFα, gp130 and IL‐6R did not change. These data suggest that HS induces cytokine gene expression in SM and this tissue may be a source of these proteins during HS recovery in mice. Research supported by MRMC. Author views not official US Army or DoD policy.
Gene expression in cardiac tissue and liver of hypoxic and hyperoxic Alligator mississippiensis
Authors: Parrilla Leah , Owerkowicz Tomasz , Steele Erin , Omori Miki , Lee Amber , Hicks James , Rourke Bryan
Published: June 2021

Oxygen levels have fluctuated between 16% and 36% as shown from burial rates of organic carbon over the past 500 million years (my). This cyclical pattern has been associated with animal extinction and implicated as a driving force for physiological adaptation. We use Alligator mississippiensis (A.M.) as a model species of longevity and adaptability. Incubated A.M. eggs were raised in oxygen conditions of 16%, 21%, 26%, 31%, and 36% representative of oxygen levels over the last 500my. We hypothesized that A.M. raised in hypoxic environments would have constraints on growth, cardiovascular load, metabolic protein expression and myosin heavy‐chain (MyHC) plasticity related to cardiovascular demands. Heart and metabolic activity in the liver were examined at embryonic, hatchling and post‐hatchling time points as indicators of phenotypic plasticity to differing oxygen environments. MyHC isoform expression was examined in all chambers. Proteomic analysis was used to identify differentially expressed liver proteins from each oxygen group using two dimensional gel electrophoresis and MALDI‐TOF/MS for protein identification. Quantitative PCR was used to measure cardiac gene expression for each oxygen group in the oxygen dependent HIF‐1α gene, E3 ubiquitin ligase gene MAFbx involved in the atrophy signaling pathway, and Myostatin involved in hypertrophy. Funded by NSF grant:IOS‐0922627 NSF RUI
A mathematical model of calcium and phosphate homeostasis and early chronic kidney disease
Authors: Pruett William Andrew , Hester Robert L
Published: June 2021

A complex network of hormones, buffers, and signaling mechanisms must work together to maintain proper calcium and phosphate levels in the human body. Quantification of this network is necessary to gain understanding about how various pathophysiologies develop, and how they can be treated. In particular, calcium and phosphate homeostasis are intertwined through the interactions of parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and 1α,25(OH)2D3 (Calcitriol). In vitro and in vivo studies were used to parameterize a model of hormone production and secretion for PTH, FGF23, and calcitriol including anabolic and catabolic pathways. In addition, it contains a three‐stage kinetic model of Vitamin D with the metabolic shunt path of 24 hydroxylation. The homeostatic mechanism includes various buffering mechanisms within the extracellular fluid compartment, hormonal influence on renal clearance mechanisms, and servo‐control of the calcium‐phosphorus product by a solubility model proposed by Talmage, Bronner, and Stein. The model responds properly to disturbances in the clearance of FGF23 characteristic in autosomal dominant hypophosphatemic rickets, and simulates low calcium or high phosphate diets properly. As an application of the model, we demonstrate the mechanism believed to describe the onset of metabolic bone disease as a complication of chronic kidney disease. In particular, renal damage reduces the ability of the kidney to create calcitriol resulting in increased PTH leading to increased FGF. When renal damage is minimal, compensation is possible, but as kidney damage becomes more intense, compensation is lost and FGF23 rises, the first general clinical indicator of skeletal involvement of CKD. This model does not include a specific bone cell axis, and is thus unable to demonstrate the effects of subsequent decompensation. This project is supported by NIH 1T32HL105324‐01 and EPSCoR 0903787.
A single‐amino acid mutation converts human aquaporin 5 to an anion channel
Authors: Qin Xue , Boron Walter F
Published: June 2021

Previous studies showed that one amino acid substitution N60G converts AQP6 from an anion to a water channel. Reverse mutation of G to N in AQP0, AQP1 and AQP2 reduced osmotic water permeability (Pf) but did not induce current. In the present study, we made single‐point mutations of AQP5 at L51, a residue that faces the central pore of AQP5, and one residue downstream from the N60 equivalent in AQP6. We evaluated function by two‐electrode voltage clamp, measurements of Pf, surface biotinylation, and extracellular surface pH (to assess CO2 permeability). We found that, whereas L51R has no H2O or CO2 permeability, it produces a current that can be blocked by the mercury derivative pCMBS. Double mutant L51R/C182S has currents that are about half those of L51R, but is now insensitive to pCMBS. L51R showed an anion permeability sequence of I− > NO3− > NO2− > Br− > Cl−. Furthermore, we made several other L51 mutants, and found that L51T (polar uncharged) and L51V (nonpolar) retain H2O and CO2 permeability and do not exhibit anion conductance; L51D and L51E (negatively charged) have no H2O or CO2 permeability, L51K and L51H (positively charged) have decreased H2O and CO2 permeability but an anion conductance. All the mutations are expressed on the oocyte plasma membrane. In conclusion, mutations of L51 can convert AQP5 to an anion channel or reduce Pf or reduce CO2 permeability. Funded by AHA 11POST7670014 & ONR N00014‐08‐10532.
Effect of iodine‐iron interactions on iodine status in double‐fortified salt intervention with female Indian tea pluckers
Authors: Hammons Julie , Venkatramanan Sudha , Haas Jere D
Published: June 2021

Previous research showed that consuming iron‐fortified salt improves iron status. Interactions between iodine and iron in double‐fortified salt (DFS) may alter the effect of DFS on iodine status. A randomized, controlled, double‐blind trial was conducted to test the efficacy of DFS as a mechanism to improve iron status. Subjects were 217 female tea pluckers, aged 19–55 yrs, from West Bengal, India. The subjects were randomly assigned to receive iodized salt (controls) or DFS for 10 months. Blood indicators of iron status were measured at baseline and end line, including hemoglobin, serum ferritin, and serum transferrin receptor. Iodine status was determined at baseline and end line by urinary iodine concentration. Subjects consuming DFS had significant improvement in iron status relative to controls. We examined the modifying effect of baseline iodine and iron status and change in iron status across the intervention on the change in iodine status. The results are discussed in the context of designing interventions in multiple‐micronutrient‐deficient settings. Supported by NSF, the Mathile Institute for the Advancement of Human Nutrition and the Micronutrient Initiative.
Age Modulates Effect of Fish Oil on the Immune Response in an Ovalbumin Asthmatic Murine Model
Authors: Histed Alexander , Lee Sanghan , Du Xiaogang , Wu Dayong , Meydani Simin Nikbin
Published: June 2021

Asthma is characterized as a chronic Th2‐mediated, inflammatory airway disease, with elevated number of eosinophils, and effector cells (CD44+CD62L−). Despite numerous studies aimed at examining the role of fish oil (FO), known for its anti‐inflammatory effects on the asthmatic response, none have considered the impact of age, which is proposed to alter the Th1/Th2 paradigm. We sought to determine how age and diet could alter the asthmatic immune response. Young (4 months) and old (22 months) female Balb/c mice were fed a diet supplemented with 10% corn oil (CO) or 8.8% FO and 1.2% CO for 30 days. Only splenocytes from old asthmatic mice showed decreases in both CD4 (29.4 ± 1.2 vs. 44.1 ± 1.2) and CD8 (13.0 ± 1.0 vs. 25.0 ± 1.3) effector cells in FO compared to CO groups (n=5, p=0.004 and 0.011, respectively). In bronchoalveolar lavage fluid, old asthmatic mice fed FO showed decreased eosinophils compared to old CO fed mice (11.2 ± 1.9 vs. 46.4 ± 7.0 respectively) (p=0.032). Our results indicate a potential mechanism for the therapeutic use of FO in elderly asthmatics. Current work is investigating the role of other pathogenic mediators. Supported by USDA contract # 58‐1950‐7‐707.
Anion transporter links to urolithiasis and hepatotoxicity
Authors: Markovich Daniel , McLeay Sarah , Lee Soohyun
Published: June 2021

Urolithiasis and hepatotoxicity are linked to perturbations in oxalate and sulfate homeostasis. Urolithiasis is a common disorder leading to significant health care costs. Drug‐induced liver damage is a major cause of death in patients with acute liver failure. Sat1 (Slc26a1) is an anion transporter that mediates epithelial transport of oxalate and sulfate in the kidney, liver and intestine. Creation of Sat1 null (Sat1−/−) mice revealed the physiological roles of Slc26a1 in vivo. Sat1−/− mice exhibit hyperoxaluria with hyperoxalemia, nephrocalcinosis and calcium oxalate stones in their renal tubules and bladder. Sat1−/− mice also have hypersulfaturia, hyposulfatemia and enhanced liver toxicity when subjected to drugs such as acetaminophen. These data suggest Sat1 regulates both oxalate and sulfate homeostasis and is critical to the development of calcium oxalate urolithiasis and hepatotoxicity.

Funding from NHMRC, ARC and CCQ grants.
FGF signaling is involved in physiological adaptation to pressure overload in developing heart
Authors: Krejci Eliska , Pesevski Zivorad , Nanka Ondrej , Sedmera David
Published: June 2021

Fibroblast growth factors (FGFs) play an important role during embryonic induction, growth and patterning. Exogenous FGF2 as well as pressure loading were shown to induce embryonic myocyte proliferation. Here we tested whether FGF2 signaling is involved in transmission of pressure overload to increased myocyte proliferation in vivo.

Pressure overload was induced by conotruncus constriction in Stage 21 chick embryos. Anti‐bromodeoxyuridine labeling was used to assess proliferation at 24, 48 and 72 h. Western blotting and RT‐PCR to measure FGF2 protein and mRNA levels was performed on ventricular extracts at 48 h interval. Blood was collected at 48 h to assess the amount of FGF2 in serum by ELISA. Proliferation of ventricular myocytes was increased significantly at 48 h. Neither western blotting, nor immunohistochemistry revealed any changes in the amount of myocardial FGF2. ELISA showed a 93% increase of FGF2 in the serum. Increased amount of FGF2 mRNA in ventricular myocardium was confirmed by real time PCR.

We conclude that FGF2 synthesis is increased in embryonic ventricular cardiomyocytes in response to increased stretch due to pressure overload. Increased stretch causes its release into serum, causing it to act in endocrine, rather then paracrine manner.

Supported by Ministry of Education VZ 0021620806, ASCR AV0Z50450515 and AV0Z50110509 and GACR P302/11/1308.

Grant Funding Source : P302/11/1308
Notch signaling through the Jagged‐1 ligand regulates mesenchymal progenitor differentiation and tissue regeneration
Authors: Hankenson Kurt D
Published: June 2021

Notch signaling regulates stem cell differentiation and expansion and influences formation and maintenance of bone. Loss‐of‐function mutations in the Notch ligand Jagged‐1, which are associated with Allagille's Syndrome, result in decreased bone mass. Notch signaling is also implicated in modulating the regeneration of a variety of non‐mineralized tissues. We hypothesize that Notch signaling through Jagged‐1 is crucial for bone regeneration through the regulation of mesenchymal progenitor cell (mesenchymal stem cell – MSC) expansion and differentiation. Canonical notch signaling through Jagged‐1 has pleiotropic, variable effects on MSC lineage progression and proliferation. Jagged‐1 activity is influenced by bone morphogenetic signaling and modulatory proteins of the thrombospondin family. Blocking canonical Notch signaling in mice results in age‐associated bone loss, while mice with conditional deletion of Jagged‐1 show related alterations in bone mass. Notch signaling is up‐regulated during both intramembranous and endochondral bone regeneration and corresponds to increases in expression of Jagged‐1. Jagged‐1 can be coupled to biodegradable biomaterials and induces increased osteoblast differentiation of MSC. Jagged‐1 coupled biomaterial can then be implanted at the site of bone defects and used to modulate bone regeneration.

This work was supported by the DOD and NIH.
The expanded repertoire of a classical intranuclear domain
Authors: Pederson Thoru
Published: June 2021

The first structure to be observed within the cell nucleus was the nucleolus, described in 1836–1839. A century would go by before it was found that this intranuclear domain is the site of ribosome biosynthesis. After another three decades, my laboratory discovered that the nucleolus also is the assembly site of the signal recognition particle, a ribonucleoprotein complex involved in the synthesis on membrane and secreted proteins. This unanticipated finding prompted us to consider yet additional functions, leading us and others to the finding that the nucleolus is involved in cell cycle control. Recently, and most surprising of all, we have found that the nucleoli of myogenic stem cells harbor a set of microRNAs, suggesting a role for this intranuclear domain beyond anything previously even remotely imagined. We are presently trying to understand the meaning of these nucleolar microRNAs and will report an initial clue. Keeping an open mind has proven essential in our work on the nucleolus.

Supported by grants from NIH, NSF and the Human Frontier Science Program Organization.
Mango consumption is associated with better diet quality and increased nutrient intakes in adult participants from the National Health and Nutrition Examination Survey (2001–2008)
Authors: Fulgoni Victor L , Nicklas Theresa A , OˈNeil Carol E
Published: June 2021

The association between mango consumption and dietary quality, nutrient intake, and physiological parameters was examined in adults using data from the National Health and Nutrition Examination Survey (2001–2008). Mango consumers were defined as those who had any amount of mangos during the first 24‐hour dietary recall. As compared to non‐consumers (n=17,451), adult (19+ years) mango consumers (n=117) had significantly (p<0.01) better diet quality as measured by Healthy Eating Index (60.8 ± 1.3 vs 50.9 ± 0.2) driven primarily by increased fruit intake (2.5 ± 0.2 vs 1.0 ± 0.02 cup equivalents). Energy intake (2152 ± 84 vs 2190 ± 10 kcal/d) was similar but total fat (77 ± 2.2 vs 83 ± 0.3) was lower (p<0.01) and dietary fiber (21.7 ± 1.3 vs 15.8 ± 0.02 g/d) was higher (p<0.01) in mango consumers as compared to non‐consumers. Vitamin C (159.4 ± 9.9 vs 87.9 ± 1.6 mg/d), magnesium (342 ± 17 vs 290 ± 2 mg/d), and potassium (3240 ± 98 vs 2713 ± 14 mg/d) were significantly (p<0.01) higher and sodium (3116 ± 99 vs 3490 ± 12 mg/d) was significantly lower in mango consumers as compared to non‐consumers. Adult mango consumers had lower body weight (77.4 ± 1.98 vs 1.6 ± 0.4 kg) but similar blood pressures and blood lipids as non‐consumers. However, C‐reactive protein levels was lower in mango consumers (0.34 ± 0.04 vs 0.42 ± 0.01mg/dL, p<0.05) relative to non‐consumers. Therefore, we conclude mango consumption is associated with better diet quality and greater nutrient density in adults. Supported by the National Mango Board and USDA.
What do College Students Want? A Qualitative Study Exploring Nutrition Language and Knowledge
Authors: Hirshberg Shira , Lipschitz Jessica , Lofgren Ingrid
Published: June 2021

Overweight and obesity can cause dyslipidemia, which has been reported in college students. Dietary therapy is an ideal form of treatment for young adults because it is effective, economical, and safe. The Focus on Food Project conducted student focus groups (N= 38) at a mid‐sized northeastern university. The sample was 68.4% female, 19.0 ± 0.9 years old and mean body mass index was 23.1 ± 2.9 kg/m2. Qualitative analysis included data reduction, display, conclusion drawing and verification and coding and data display used NVivo 9. Analysis highlighted several themes; first, students use language different from that of common health messages (i.e “greasy” instead of “high in fat”). Second, students care about nutrition and want more information in the dining halls, including nutrition facts‐type labels and ideas for quick, healthful meals. Third, students were knowledgeable about the health benefits of fruits and vegetables, the importance of moderation and variety, and the health concerns related to consuming sugary beverages. Fourth, they are unsure of how to eat healthfully on‐campus and of the difference between healthful and unhealthful fats, and do not know where to obtain reliable nutrition information. Findings provide awareness of student language and knowledge that can direct nutrition educators in creating relevant, appropriate and attention‐grabbing education programs for college students.

Research was supported by the USDA

Grant Funding Source: USDA
Effect of ω3 PUFA on diet induced non‐alcoholic fatty liver disease (NAFLD) development and progression in C57BL/6J mice
Authors: Depner Christopher M , Jump Donald B
Published: June 2021

The incidence of NAFLD and non‐alcoholic steatohepatitis (NASH) has increased in parallel with obesity. While both are characterized by excessive hepatic lipid accumulation, NASH is defined as hepatic inflammation with hepatocellular damage. Our goal was to examine the effect of C20–22 ω3 PUFA on diet induced NASH in LDLR−/− C57BL/6J mice. Mice consumed the Western Diet (WD) supplemented with olive oil, eicosapentaenoic acid (20:5ω3; EPA), docosahexaenoic acid (22:6 ω3; DHA) or both EPA and DHA for 16 weeks. The WD induced a severe phenotype similar to human NASH; including robust induction of hepatosteatosis, inflammation (MCP1) and fibrosis (ProCol1α1). While dietary C20–22 ω3 PUFA failed to suppress hepatic steatosis, ω3 PUFA attenuated markers of inflammation, fibrosis, and liver damage (plasma ALT, AST). The ω3 PUFA effect on inflammation & fibrosis correlated with the down regulation of multiple transcripts involved in toll‐like receptor signaling (TRL2, TRL4, CD14). Moreover, DHA was significantly more effective than EPA or the combination of EPA & DHA at suppressing markers of inflammation and fibrosis associated with NASH. Thus, dietary ω3 PUFA attenuates inflammation & fibrosis without suppressing hepatic lipid.

Research Support: USDA Grant 2009‐65200‐05846
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)
Physical principles underlying cadherin‐mediated cell‐cell recognition
Authors: Honig Barry
Published: June 2021

A variety of cell‐cell adhesion processes are mediated by the (trans) dimerization of cadherin proteins presented from apposing cell surfaces. A multiscale combined experimental/theoretical approach to this general problem will be described with particular focus on the development of a correlation between measured binding affinities at the molecular level and cell‐cell adhesive specificity. Following cell‐cell contact, cadherin dimers cluster together to form cell‐cell junctions. Since such clustering does not occur in the absence of cell‐cell contact, there is a necessary coupling between trans and lateral (cis) interactions. The molecular mechanism that underlies this coupling will be discussed and is characterized in detail through combination of x‐ray crystallography and coarse grained simulations. In addition to the insights that will be discussed in the context of cadherin function, general principles that may underlie the molecular basis of many cell‐cell adhesion processes will be proposed. This work was supported by NSF, MCB‐0918535
Synthesis of the plant cell wallˈs most complex glycan: pectin ‐ surprises in glycosyltransferase processing and anchoring in the Golgi
Authors: Mohnen Debra , Atmodjo Melani , Tan Li , Amos Robert , Zhua Xiang , Atwood James A. , Orlando Ron , Burrell Amy , Sakuragi Yumiko , Hao Zhangying
Published: June 2021

Plant cell walls impart structure and identity to plant cells, have roles in growth, development and defense against microbes, and constitute renewal biomass for biofuel and biomaterial production. Plant walls are comprised of cellulose, the matrix polysaccharides pectin and hemicellulose, cell wall proteins and in many secondary walls, lignin. Pectin is the most structurally complex polysaccharide. The Arabidopsis GAUT1‐related gene family encodes 15 GAUT (GAlactUronosylTransferase) and 10 GATL (GAUT‐Like) proteins that are members of CAZy GT8. GAUT1 is a pectin biosynthetic homogalacturonan (HG):galacturononosyltransferase (GalAT) that is part of a Golgilocalized HG:GalAT GAUT1:GAUT7 core complex. GAUT1 is proteolytically processed and its transmembrane domain removed, leaving the question of how GAUT1 is retained in the Golgi lumen. Biochemical and fluorescent fusion‐protein studies show that GAUT1 is anchored in the Golgi lumen by a reducing agent‐sensitive association with GAUT7. Immunoadsorption of the GAUT1:GAUT7 complex and mass spectrometry identified 12 additional putative GAUT protein complex members whose identities suggest that pectin synthesis may occur as domains. The recent identification of a novel wall glycoconjugate structure is consistent with this view. The data support a role for GAUTs in synthesizing diverse pectic cell wall domains in primary and secondary walls. Funding from USDA AFRI 2010‐65115‐20396; NSF‐MCB 0646109, DOE DE‐FG02‐09ER20097 and BioEnergy Science Center grant DE‐PS02‐06ER64304. BioEnergy Science Center is a U.S. Department of Energy Bioenergy Research Center supported by Office of Biological and Environmental Research in DOE Office of Science.
Effects of bitter melon and toll‐like receptor (TLR) 4 on glucose and lipid parameters in mice fed high fat diet
Authors: Meister Maureen , Ter Sin Ee , Baker Denise , Peterson Sandra , Clarke Stephen L , Smith Brenda J , Lucas Edralin A
Published: June 2021

Bitter melon (Momordica charantia, MC) has been shown to improve markers of insulin resistance including adiposity, glucose and lipid profile in mice fed high fat diet. Fatty acids can activate toll‐like receptor (TLR) 4 signaling pathway resulting in the enhanced production and secretion of proinflammatory cytokines which may contribute to insulin resistance associated with diet induced obesity (DIO). The objective of this study was to examine the effect of MC on glucose and lipid homeostasis in an animal model of DIO and the role of TLR4 in mediating these effects. Eight week old male TLR4 mutant (C3H/HeJ) and control (C57BL/6) mice were randomly assigned to four dietary treatment groups for eight weeks (n=12–13/group): control (10% calories from fat), high fat (HF, 60% calories from fat), HF+1% (w/w) MC, and HF+10% (w/w) MC. Our preliminary data suggests that the C3H/HeJ strain exhibited significantly higher body weight, body fat, plasma cholesterol, and triglycerides in response to a high fat diet when compared to the C57BL/6 strain regardless of dietary treatment. However, C3H/HeJ strain had significantly lower area under the curve after a glucose tolerance test, plasma fructosamine and free fatty acid in comparison to the C57BL/6 strain. Mice fed the 10% MC, but not the 1% MC, improved glucose tolerance in the C57BL/6 but not the C3H/HeJ strain, suggesting MC may act through TLR4 signaling to modulate glucose homeostasis. The effects of MC and TLR4 mutation on mRNA expression of genes involved in glucose and lipid metabolism are currently being assessed. (Supported by USDA,#2008‐35200‐18692)
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
Parenting styles moderate links of feeding practices to odds of child obesity and overweight
Authors: Okwonga Ajok Beatrice , Hubbs-Tait Laura , Topham Glade , Larzelere Robert , Rutledge Julie , Cui Lixian , Kennedy Tay Seacord , Page Melanie , Harrist Amanda
Published: June 2021

Study objective was to determine the influence of parenting styles on links between feeding practices and odds of overweight and obesity in children (n=269) followed from 1st to 3rd grades. In 1st, 2nd, and 3rd grades, 73, 90, and 87 children had BMI ≥ 85th %tile and 33, 42, and 45 children had BMI ≥ 95th %tile. Modeling was associated with lower odds of child obesity for 2nd (OR = 0.365; 95% CI: 0.143–.929, p = .034) and 3rd grade children (OR = .453; 95% CI: 0.186–1.105, p = .082) of mothers above the median on authoritative parenting style but not for children of mothers below the median on authoritative style. Restriction was associated with increased odds of overweight for children of mothers higher but not lower on permissive parenting style; for 1st grade: OR= 2.522, 95% CI: 1.342 – 4.742, p = .004; for 2nd grade: OR =1.996, 95% CI: 1.139 – 3.497, p = .016. Results help resolve inconsistent findings on feeding practices and child weight status. Implications for prevention include education of both parents and nutrition educators about importance of parenting styles for the link between feeding practices and reduced odds of child overweight and obesity. Funding: USDA 2004‐05545
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
Point mutations in Escherichia coli DNA pol V that confer resistance to non‐cognate DNA damage
Authors: Hawver Lisa A , Tehrani Mohammad , Kania Danielle , Muser Stephanie , Beuning Penny J
Published: June 2021

When DNA is damaged, replicative DNA polymerases such as E. coli DNA polymerase (pol) III cannot continue replication past this damage. One of the pathways in the cell to cope with such damage is the SOS response that regulates the expression of at least 57 genes, including umuDC and dinB, which encode the Y family DNA polymerases UmuD′2C (pol V) and DinB (pol IV), respectively. UmuD′2C (pol V) is composed of the cleaved form of UmuD, UmuD′2, and UmuC, the polymerase subunit. UmuD′2C is specialized to bypass abasic sites and thymine‐thymine dimers, while DinB specializes in bypass of N2‐dG adducts such as N2‐furfuryl‐dG. Y family polymerases can also replicate undamaged DNA in an error‐prone manner and therefore play a role in mutagenesis and possibly antibiotic resistance. Using hydroxylamine, we generated a library of UmuC mutations from which we then selected those that had the ability to confer survival to nitrofurazone, which is believed to cause predominantly N2‐furfuryl‐dG lesions. We tested in vivo the ability of these selected UmuC variants to confer survival after UV irradiation, as well as their ability to confer the cold sensitivity phenotype and to inhibit RecA‐mediated homologous recombination. In addition, further characterization suggests that some of these variants may interrupt interactions with UmuD. Supported by Res. Corp. for Sci. Adv. and NSF MCB‐0845033.
The Escherichia coli SOS‐induced umuD gene products interact with single‐stranded DNA binding protein
Authors: Silva Michelle Cristine , Chan Monyrath , Beuning Penny J
Published: June 2021

E. coli single‐stranded DNA binding protein, SSB, is a protein that binds single‐stranded DNA (ssDNA) present in the cell and prevents it from forming secondary structures. It is composed of four identical monomers each consisting of an OB domain and a C‐terminal tail. The OB domain is responsible for binding to ssDNA as it contains the tryptophan and phenylalanine residues that interact with the nucleotide bases of ssDNA through base‐stacking interactions. The C‐terminal tail is responsible for binding other proteins. To date, 15 proteins involved in replication, repair, and recombination have been shown to bind SSB. Most of these binding partners have been shown to interact with the C‐terminal tail of SSB. The binding sites of the remaining binding partners have not been determined. Recently our lab has determined that UmuD2, a protein involved in the cell's SOS response to DNA damage, also binds SSB. Furthermore, we have determined that unlike other proteins, UmuD2 does not bind the C‐terminal tail; instead, it binds the OB domain. We have determined that SSB inhibits cleavage of the UmuD N‐terminal arms, a process important for regulating SOS mutagenesis. Research supported by NSF MCB‐0845033.
Molecular dissection of hemolysin A template‐assisted activity
Authors: Weaver Todd Michael , McDermott James Joyce
Published: June 2021

In this study, the role of molecular organization was investigated as related to hemolysin A (HpmA265) template‐assisted behavior. Previous studies have shown that full‐length HpmA can be activated through interaction with purified HpmA265 in template‐assisted fashion. HpmA265 was analyzed via template‐assisted hemolysis, circular‐dichroism, size‐exclusion chromatography and multi‐angle light scattering (SEC‐MALS) before and after tryptic digestion. The results from these investigations were utilized to determine the absolute molecular weight of the template‐assisted active species. The pre‐tryptic digestion data reported a heterogeneous mixture of HpmA265 monomer and dimer. Quantitative hemolytic assays have determined the monomer to be the molecularly active species. Subsequent tryptic digestion, followed by SEC‐MALS, generated a homogenous dimeric species with enhanced template‐assisted behavior and thermal stability. From these data, a new model for template‐assisted activity has been developed where exposed, homogenous, and monomeric on‐edge beta‐strands of HpmA265 facilitate the activation of full‐length HpmA. These findings are significant and may apply to other beta‐helix protein dependent disease states like Alzheimer's Parkinson's and transmittable prion disorders. National Science Foundation Grant (MCB0744754) and (MCB1050435) supported the work.
Biophysical Characterization of Acyl Carrier Protein Domains from a Polyunsaturated Fatty Acid Synthase
Authors: Rodriguez Uldaeliz Trujillo , Oyola-Robles Delise , Arold Stefan , De Melo Fernando Alves , Ladbury John E. , Vazquez Edwin , Vega Irving E. , Baerga-Ortiz Abel
Published: June 2021

Acyl carrier protein (ACP) is a highly conserved protein domain that plays a key role in the biosynthesis of fatty acids and polyketides. The polyunsaturated fatty acid synthase complex from deep‐sea bacteria contains a total of five ACP domains in tandem. No satisfying explanation exists for the selection of this rare arrangement. In an effort to characterize the function of the tandem ACP arrangement, we have expressed individual and tandem ACP in E coli. Structure of tandem ACP in solution was determined by small angle X‐ray scattering (SAXS) in combination with circular dichroism (CD) and differential scanning calorimetry (DSC). SAXS shows that tandem ACP exhibits a flexible beads‐on‐string arrangement. The structural model of tandem ACP was validated by CD and DSC, which show that ACPs are stable and mainly composed of alpha‐helices. Interactions between DH and ACP domains with different bound acyl intermediates, were measured by microscale thermophoresis (MST). A binding affinity [Kd = 306 nM] varies with the acyl intermediate. The results from this work help us to gain insight into the role of tandem ACP arrangement in the biosynthesis of omega‐3 fatty acids. This work was funded by MBRS‐RISE Program, Grant R25GM061838 and NSF Grant CHE0953254.
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
Probing the Role of Proline‐288 in the Regulation of Agrobacterium tumefaciens ADPGlucose Pyrophosphorylase
Authors: Bains Gagandeep , Guzman David , Sanders Jamie , Karzai Hoomai , Bor Simona , Orry Andrew , Meyer Christopher R
Published: June 2021

ADP‐glucose pyrophosphorylase (ADPG PPase) catalyzes the rate limiting step in glucan synthesis pathways of bacteria and plants and is an attractive target for protein engineering to increase the production of renewable carbon. Agrobacterium tumefaciens (Ag.t.) ADPG PPase is activated by F6P and pyruvate and inhibited by Pi; these effectors are believed to bind at allosteric site(s) located between the catalytic N‐terminal and C‐terminal domains. We probed the role of highly conserved P288 in the loop region between the two domains that has shown to be vital in regulation of the E. coli ADPG PPase. The P288A and P288D mutants were successfully expressed and purified while P288G was found to be unstable. P288A displayed a decrease in activity and fold activation by activators versus wild‐type while the P288D enzyme showed ~5‐fold higher activity than wild‐type and insensitivity to activation and inhibition by effectors. The mutations may alter the loop conformation that positions the domains, resulting in enzyme activation, particularly when negative charge is at this site. Molecular modeling indicates the loop region may interact with another subunit in the tetrameric structure of the enzyme. Efforts are underway to test this hypothesis by additional mutagenesis and structural studies. Supported by NSF Award 0448676.