bluuebunny/crossref_metadata_2025_split huggingface dataset:
BECN Homologs And ATG14 Form A Metastable Coiled‐Coil To Mediate Autophagy
Authors: Sinha Sangita , Su Minfei , Li Yue , Levine Beth , Colbert Christopher 
Published: June 2021

Autophagy, an essential eukaryotic cellular homeostasis pathway, is responsible for sequestration of unwanted, damaged or harmful cytoplasmic components in vesicles called autophagosomes, followed by their lysosomal degradation, thereby enabling nutrient recycling. Autophagosome nucleation is mediated by Class III phosphatidylinositol 3‐kinase complexes that include two key autophagy proteins, a BECN (also called Beclin, ATG6 or VPS30) homolog and ATG14/BARKOR. BECN1 was amongst the first mammalian autophagy proteins to be identified1. Recently, mammals were shown to encode a second BECN paralog, BECN22. BECN2 shares 57% sequence identity with BECN1 is also involved in autophagy as well as in ligand‐induced endolysosomal degradation of several cellular GPCRs. BECN2 heterozygous knockout mice have defective autophagy, increased levels of brain cannabinoid 1 receptor, elevated food intake, obesity and insulin resistance2. Further, BECN2 regulates endolysosomal degradation and oncogenic signaling of GPCRs encoded by the Kaposi's Sarcoma‐associated herpesvirus3.Here we focus on understanding the structure of the helical, coiled‐coil domain (CCD) of BECN homologs and the similarities and differences in their interaction with ATG14. X‐ray crystal structures of the CCDs of human BECN1 and BECN2 (unpublished data), show that they form similar autophagy‐inactive, anti‐parallel homodimers, which includes six and seven non‐ideal packing interactions respectively, although the BECN2 CCD homodimer is significantly more curved and has a tighter binding affinity than that of BECN1. Conversely, the CCDs of both BECN1 and BECN2 bind the ATG14 CCD to form a parallel, curved heterodimer stabilized by multiple, conserved polar interactions. Isothermal calorimetry experiments demonstrate that compared to BECN1, the BECN2 CCD forms a stronger heterodimer with the ATG14 CCD. Mutation of non‐ideal BECN1/BECN2 interface residues to more ideal pairs improves homodimer self‐association and thermal stability. Many of these BECN1 mutations knock‐out binding to ATG14, but all BECN2 CCD mutants bind ATG14, although more weakly than wild‐type. Thus, polar CCD interface residues of BECN homologs result in a metastable homodimer, facilitating dissociation; but enable better interactions with polar ATG14 residues stabilizing the BECN:ATG14 heterodimer. Further, these structure‐based mechanistic differences in BECN1 and BECN2 homodimerization and heterodimerization likely dictate competitive ATG14 recruitment within the cell.Support or Funding InformationThis work was supported by NIH grants RO3 NS090939 (S.C.S.) and R15 GM113227 (C.L.C.); a National Science Foundation grant MCB‐1413525 (S.C.S.); and NSF and North Dakota EPSCoR grant II‐1355466 doctoral dissertation awards for M.S. (PI: S.C.S.).
Role of the inter‐subunit surface interaction in the regulation of the ADP‐glucose pyrophosphorylase from Agrobacterium tumefaciens
Authors: Patel Hiralben P. , Dobrzynski Emily , Liu Dali , Ballicora Miguel A. 
Published: June 2021

ADP‐glucose pyrophosphorylase (ADP‐Glc PPase) is a key regulatory enzyme involves in the starch and glycogen synthesis for plants and bacteria respectively, which catalyzes the synthesis of ADP‐glucose from glucose 1‐phosphate (Glc1P) and ATP. ADP‐Glc PPase from Agrobacterium tumefaciens is allosterically regulated by fructose 6‐phosphate (Fru6P) and pyruvate (Pyr). Previously, it was observed that removal of a disulfide bridge between the α‐subunits of the potato tuber enzyme resulted in a more active enzyme [1], indicating that inter‐subunit interactions are important in the allosteric mechanism [2]. By studying the structure of the ADP‐Glc PPase enzyme of Agrobacterium tumefaciens, it comes to light that D141 is interacting with the R11 of the opposing subunit [3], which was suggested to be involved in activation by pyruvate [4]. To prove our hypothesis that D141 and R11 residues are involved in regulation, we made three single mutants: D141A, D141R, R11D, and the double mutant R11D‐D141R. D141A exhibited reduced Vmax values in the absence of activators (~4‐fold), reduced apparent affinity for Fru6P (~2.5‐fold), and lower apparent affinity for ATP (~3‐fold). In the presence of Fru6P, D141A exhibited only ~4.3% of the wild‐type activity, and affinity for ATP was not affected as well indicating a virtual insensitivity to Fru6P. When D141R was compared to wild‐type enzyme, the activity lowered ~3600‐fold. For D141R the apparent affinity for ATP was decreased in the presence of Fru6P. R11D was similarly active as the wild‐type, while it is completely insensitive to both activators Fru6P and Pyr. The double mutant R11D‐D141R was showing decreased activity (~95‐fold) in compared to wild type, and insensitive to both activators. Our results suggest that the functional role of the D141 and R11 residues is to interacting with the opposing subunit and enabling the regulation of the ADP‐Glc PPase.Support or Funding InformationNational Science Foundation
Regulation of Phosphatidic Acid Phosphatase by High Glucose in the Oleaginous Yeast Yarrowia lipolytica
Authors: Hardman Derell , Fakas Stylianos 
Published: June 2021

Phosphatidic acid phosphatase (PAP) catalyzes the conversion of phosphatidic acid to diacylglycerol, which is considered the committed step in triacylglycerol (TAG) biosynthesis. TAG biosynthesis in oleaginous microorganisms like Yarrowia lipolytica is typically triggered by high glucose amounts and results in cells accumulating lipids made mostly of TAGs. The objective of this work was to study the regulation of PAP during lipid accumulation induced by high glucose amounts. We hypothesized that the induction of TAG biosynthesis under these conditions should be mediated by PAP. In this work, we grew Y. lipolytica in a high glucose media (HGM) that favors lipid accumulation and in a low glucose media (LGM) where lipid accumulation is minimal. We measured PAP activity and lipid amounts throughout the cultivation period. Our results showed that, over time, the TAG amounts increased eight‐fold in the HGM cultures, while there was no increase in the LGM cultures. PAP activity was induced during TAG accumulation in HGM, which resulted in a two‐fold increase in activity. In contrast, PAP activity was down‐regulated in the LGM cultures, and that decrease coincided with the complete consumption of glucose in the medium. These results indicate that PAP plays a role in the regulation of lipid accumulation in Y. lipolytica.Support or Funding InformationThis project was supported by the Evans‐Allen Grant no.1005735 and Capacity BuildingGrants Program Grant no.1007503 from the USDA National Institute of Food and Agriculture.
Is Food Security Influencing Emotional Health? A Study with Hispanic Immigrant Mothers
Authors: Villegas Elizabeth , Hannon Bridget , Hammons Amber , Teran‐Garcia Margarita , Wiley Angela 
Published: June 2021

IntroductionHispanic immigrants in the U.S. often face a number of negative conditions that influence their emotional health. These problems can be heightened when there are low resources such as food insecurity and pressing stressors. This study looks to understand if food insecurity and acculturation predict depression levels for Hispanic immigrant mothers. From previous literature we hypothesize that food insecurity and higher levels of stress will predict higher depression levels.MethodsThis study used the Larger Multi‐State Abriendo Caminos Intervention program data. Hispanic immigrant mothers completed surveys at pre‐post and 6 month follow up time points. Food security was measured with USDA food security short module. Depression was measured with the CESD‐10 questionnaire and stress with Cohen's perceived stress scale. Multiple regression models were used to analyze data collected at baseline for the Illinois and California cohorts (N= 100). Among our participants, 36% reported some food insecurity with 6% of those having very low food security. Furthermore 24% had depression and, compared to other Hispanic populations, our participants had high levels of stress.ResultsHigher levels of food insecurity significantly predicted maternal depression (β = 0.314, p <0 .001), regardless of acculturation level. Food insecurity explained 10% of the variance in rates of depression and in this analyses higher acculturation levels to Anglo American behaviors account for another 2% of the variance although it is not significant. In addition, when stress was included in the analyses it accounted for an additional 23% of model variance and was a significant predictor of depression (β = 0.48, p < 0.001).ConclusionWe found that food insecurity and stress significantly predicted depression regardless of acculturation level. These psychological variables have been associated with food consumption patterns and weight‐related outcomes in other low income populations. Therefore, our findings suggest the importance of including food insecurity and psychological variables in future research to explore possible interactions with effects on nutritional and behavior outcomes.Support or Funding InformationThis project was supported by Agriculture and Food Research Initiative Competitive grantno. 2015‐60001‐23246 from the USDA National Institute of Food and Agriculture.
Infant formula feeding alters the proliferative status of neonatal mammary glands independent of estrogen signaling
Authors: Bhattacharyya Sudeepa , Mercer Kelly E , Hennings Leah , Chaudhurry Mousumi , Yeruva Laxmi , Ronis Martin , Badger Thomas 
Published: June 2021

Soy infant formula contains many phytochemicals, including phytoestrogens, which are structurally similar to estradiol (E2). The mammary gland is particularly sensitive to estrogens, and there are concerns that use of soy‐based infant formulas may potentially have adverse effects on mammary tissue development. In this study, we fed female piglets a soy‐based infant formula, a dairy milk‐based infant formula, or milk formula supplemented with E2, in comparison to piglets receiving sow's breast milk from postnatal day 2–21. Interestingly, we observed a slight but significant increase in terminal end bud number in the mammary glands of the all formula fed groups compared to the sow's milk control. Microarray analysis identified 976 differentially expressed genes between mammary glands from milk formula, soy formula and milk formula supplemented with E2 vs sow fed piglets (±1.5 fold, P<0.05). Of these genes, 45% were held in common between all formula groups. E2 supplemented milk formula altered 369 genes. Milk and soy formula altered 45 and 69 genes, respectively, in comparison to the sow's milk control. Functional annotation analysis indicated up‐regulation of angiogenesis, adipocyte differentiation, and canonical Wnt signaling pathways in the formula fed groups. Real‐time RT‐PCR confirmed decreased Wnt10b mRNA expression, and increased Wnt2b, cyclin D and n‐myc expression, suggesting an heightened proliferative state in the mammary glands of formula fed piglets compared to piglets receiving sow's milk, P<0.05. Pathways unique to the soy formula group had no apparent relevance to mammary gland development and/or function. Real time RT‐PCR expression of the E2‐responsive genes progesterone receptor (Pgr) and transforming growth factor beta‐2 (Tgfb2) were significantly up‐regulated in the E2‐supplemented formula group, compared to the milk formula and soy formula groups and the sow's milk control. These data show that dietary exposure to phytoestrogens associated with soy infant formula do not elicit an estrogenic response in the developing mammary gland. However, the neonatal mammary gland is generally quiescent. Our data also suggest that infant formula feeding may initiate proliferative and cell differentiation pathways independent of estrogenic signaling.Support or Funding InformationThis work was funded by USDA‐ARS Project 6026‐5100‐010‐05S.
Proteomic Analysis of 3T3‐L1 Adipocytes Treated with Methylglyoxal; The Potential Impact of Dietary Sugar on Adipocyte Metabolism
Authors: Komanetsky Susan M , Hedrick Victoria , Sobreira Tiago Jose Paschoal , Kim Kee Hong 
Published: June 2021

Rising levels of obesity in the United States (US) and in nations adopting a Western diet are of concern due to the associated risk of chronic diseases. As an endocrine organ, adipose tissue regulates whole body immunity and energy homeostasis, but during obesity, disruptions in the normal metabolism of adipocytes, such as increased oxidative stress and reduced mitochondrial function, may contribute to disease development. Diets high in added sugar, particularly sucrose and high fructose corn syrup, may induce metabolic abnormalities in adipocytes by increasing the rate of glycolysis and the accumulation of glycolytic metabolites. Methylglyoxal (MG), a highly reactive metabolite of glycolysis, damages proteins and other cellular components. MG is found at higher concentrations in the serum and tissues of individuals with diabetes and is directly involved in the pathophysiology of diabetic complications, however, MG may have negative effects on cell metabolism before the onset of disease. Recent studies using animal models suggest MG accumulates in adipose tissue during high fructose feeding and impairs insulin signaling pathways. However, the specific effects of MG in adipocytes require further investigation. The objective of this study was to characterize changes in the proteome of mature adipocytes exposed to non‐toxic levels of MG. We treated fully differentiated 3T3‐L1 adipocytes with either MG or PBS as a control for 48 hours. Cells were collected, delipidated, and proteins precipitated. After denaturation, in‐solution protein digestion was performed with trypsin and the resulting peptide fragments were separated by liquid chromatography and scanned by mass spectrometry (MS), followed by additional MS/MS scanning. MS/MS data was analyzed with MaxQuant software and proteins identified by comparison with the Uniprot mouse database. The proteome of MG‐treated adipocytes was characterized by reduced expression of both mitochondria‐related proteins and proteins involved in endogenous antioxidant pathways. In addition, MG treatment altered the expression of proteins involved in several key metabolic pathways, including oxidative phosphorylation, the citric acid cycle, and pyruvate metabolism. We conclude that MG induces changes in adipocytes which may not only contribute to oxidative stress, but which may disrupt normal metabolic pathways. Though this may represent a temporary adaptation to MG exposure, over time, repeated such exposures may make adipocytes more vulnerable to the serious metabolic abnormalities known to be associated with obesity‐related diseases.Support or Funding InformationUSDA NIFA grant #2011‐38420‐20038, Core Pilot grant Indiana Clinical and Translational Sciences Institute #UL1TR001108
The efficacy of nano‐emulsification to improve vitamin D bioaccessibility
Authors: Kadappan Alagu Selvi , Gumus Cansu E. , Bessey Amy , McClements David J. , Wood Richard J. , Liu Zhenhua 
Published: June 2021

Observational, preclinical and clinical studies strongly suggest that vitamin D deficiency is associated with a wide range of diseases, including multiple forms of cancer with the colorectal cancer (CRC) in particular. Vitamin D is among those nutrients and dietary bioactive components that receive substantial attention for CRC prevention. However, after several decades of research, we still lack an efficient dietary strategy to improve vitamin D status. The prevalence of vitamin D inadequacy and deficiency is still common, up to 32%, in the United States. Using an in vitro simulated gastrointestine (GI) system, the present study examined the efficacy of oil‐in‐water nanoemulsion in improving vitamin D bioaccessibility. Comparing to the conventional emulsion of vitamin D with corn oil, the nanoemulsion significantly altered the physiochemical properties of the lipid particles. Nanoemulsion increased negative charges, as indicated by larger negative values of the ζ‐potential, across all the stages of simulated GI tract consisting of mouth, stomach and small intestine phases (p < 0.05), and the particle sizes were significantly decreased along those stages (p < 0.05). Nanoemulsion prevented the loss of cholecalciferol though the simulated GI tract and improved its content in the intestinal digesta by 3.94 folds (p < 0.05), and further improved the incorporation of vitamin D into micelles by 16.7% (p < 0.05). Taken together, the nanoemulsion improved the bioaccessibility, as evaluated by the in vitro simulated GI model, by 4.60 folds. These results provide useful information for designing nanoemulsion‐based delivery system to improve vitamin D status.Support or Funding InformationSupported in part by the United States Department of Agriculture (2014‐67017‐21762 and MAS00454) and UMass Honors Research Grant
Higher‐Protein Intake during Sustained Negative Energy Balance Attenuates Elevations in Resting Metabolic Rate at High Altitude (4300 m)
Authors: Derosier Allyson , Berryman Claire E. , Karl J. Philip , Wilson Marques , Young Andrew J. , Pasiakos Stefan M. 
Published: June 2021

Resting metabolic rate (RMR) increases in unacclimatized lowlanders who ascend from sea level (SL) to high altitude (HA), contributing to negative energy balance and lossof total body mass. Although RMR declines progressively during HA acclimatization, in part due to the loss of metabolically active fat‐free mass(FFM), RMR remains higher than at sea level (SL) for at least the first 3 wk of residence at HA. At SL, consuming a higher‐protein diet during negative energy balance spares FFM during weight loss, which mitigates the decline in RMR that typically accompanies weight loss. While an elevated RMR aids continued weight loss at SL, this effect may be detrimental while trying to maintain weight at HA. This study examined the effects of protein intake on RMR in 17healthy male SL residents (mean ± SD, 23.4 ± 5.6 y, 81.9 ± 13.9 kg)during a 22 d period of negative energy balance at HA. At SL, volunteers were given dietary instruction to consume a weight maintenance diet containing 1.0 g protein/kg/d for 21 d. Volunteers were then transported to HA (4300 m, Pikes Peak, CO) where they lived for 22 d. On arrival at HA, volunteers were randomized to consume a controlled standard protein (1.0 g protein/kg/d, STD) or higher‐protein(2.0 g protein/kg/d, HIGH) diet designed to elicit a 40% energy deficit (30%caloric deficit, 10% increase in physical activity). Prescribed physical activity and diet were closely supervised. Body weight was measured daily anybody composition was assessed by dual‐energy x‐ray absorptiometry at the end of both SL and HA. RMR was measured on day 0 at SL and days 1, 3, 5, 7, 10, 13, and 19 at HA. RMR was 1769 ± 206 kcal/d at SL (no group differences, P>0.05)and increased to 2777 ± 538 kcal/d on day 1 at HA (P<0.01). Importantly, during HA, RMR decreased to a greater extent in HIGH compared to STD (2339 ±446 vs. 2470 ± 439 kcal/d, main effect of diet P=0.02). Total weight loss (HIGH: −7.8 ± 1.2 vs. STD: −8.0 ± 2.6 kg), FFM loss (HIGH: −3.2 ± 1.5 vs. STD: −4.0 ±3.3 kg) and fat mass loss (HIGH: −3.9 ± 0.8 vs. STD: −3.3 ± 1.8 kg)did not differ between groups (P>0.05), and changes in FFM and fat mass were not associated with RMR (P>0.05). Consuming 2.0 g protein/kg/d during sustained negative energy balance at HA minimizes elevations in RMR. Whether changes in RMR due to higher‐protein intake would result in attenuated weight loss after a more prolonged stay at HA or with a less severe energy deficit requires further research. The opinions or assertions contained herein are the private views of the author(s) and are not to be construed as official or reflecting the views of the Army or the Department of Defense.Support or Funding InformationSupported by USAMRMC.
RELATIONSHIPS BETWEEN HEMODYNAMIC AND SYMPATHETIC NEURAL RESPONSES TO HEAD‐UP TILT DURING MODERATE DEHYDRATION IN HUMANS
Authors: Posch Alexander Morley , Luippold Adam , Mitchell Katherine , Bradbury Karleigh , Cheuvront Samuel , Kenefick Robert , Charkoudian Nisha 
Published: June 2021

Dehydrationcan cause an increase in supine sympathetic nerve activity (SNA) and heart rate(HR). Reflex sympatho excitation and tachycardia are classic baroreflex responses to orthostasis, increasing peripheral resistance and cardiac output, respectively, to maintain arterial pressure during upright posture. We hypothesized that the sympathetic nervous system would have a greater contribution to blood pressure regulation during orthostasis in dehydrated people compared to conditions of euhydration. We studied 14 young healthy subjects (4 F, 10 M) divided into 2groups: euhydrated (EUH, n = 6), previously exercised in 40 ºC while maintaining hydration; and dehydrated (DEH, n = 8), previously exercised in 40 ºC who lost ~4% of body weight via sweat loss. We measured supine muscle SNA (MSNA), HR, blood pressure (BP) during a 7minute baseline period, followed by MSNA, HR and BP responses to 30 and 45º HUT(2 minutes each). Supine MSNA was not different between groups (24 ± 9 vs 28 ±11 bursts/min, P > 0.05). HR and MSNA increased in all subjects during HUT, and mean responses were not different between groups (P>0.05). Individual changes in HR (ΔHR) were directly related to changes in MSNA (ΔMSNA) during 45ºHUT in both hydration conditions (EUH: R=0.92; DEH: R=0.92), suggesting similar responsiveness in both arms of the baroreflex. The MSNA ‐ HR relationships were weaker at 30º HUT in both groups. During DEH, ΔMSNA and ΔBP were positively related(30º HUT: R = 0.57; 45º HUT: R = 0.88); this was not seen in EUH. Our data suggest that, during exercise induced dehydration, there is an augmented contribution of the sympathetic nervous system to BP regulation.Support or Funding InformationFunded by USAMRMC; author views not official US Army or DOD policy.