bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiorespiratory Fitness, Hippocampal Subfield Volumes, and Pattern Separation Task Performance in Older Adults
Authors: Kern Kathryn L. , Nauer Wehr Rachel K. , Storer Thomas W. , Schon Karin 
Published: April 2020

Cognitive aging is associated with reduced integrity of the medial temporal lobe memory system. A key facet of episodic memory that demonstrates behavioral impairment with aging is pattern separation (PS), or the disambiguation of similar stimuli during neural encoding. PS is supported by the dentate gyrus (DG), a subfield of the hippocampus that demonstrates striking plasticity in response to exercise. Recent work from our laboratory has demonstrated that increasing cardiorespiratory fitness (CRF) through exercise training is associated with increased left anterior DG/CA3 volume and improved PS task performance in young adults. However, how these variables interact in cognitive aging is unknown, yet critical, given that aging is associated with impairments in hippocampal plasticity and PS task performance. Based on our findings in young adults, we predicted that CRF would positively correlate with DG/CA3 volume and PS task performance in older adults. Secondly, given the suggested role of the DG in PS task performance in humans, we predicted that DG/CA3 volume would significantly correlate with PS task performance. Sixty‐four participants aged 55–85 years underwent a submaximal treadmill test to estimate maximal oxygen uptake (VO2MAX), which operationally defined CRF, an MRI scan to examine volume of the hippocampal subfields, and a behavioral task designed to tax PS at parametrically varying levels of stimulus similarity (10, 30, 50%). There was a significant effect of similarity on PS task performance, with participants demonstrating lowest task accuracy in the condition theoretically placing the highest taxation on PS (50%). Left DG/CA3 body volume significantly predicted performance in the 50% condition. However, there was no relationship between CRF and PS task performance. Furthermore, while CRF did not predict DG/CA3 volume, it did significantly predict right and left subiculum volume, which may be unique to female participants between the ages of 60–80 years. Altogether, these findings provide support for a role of the DG in PS in older adults and suggest a relationship between CRF and hippocampal subfield volume that may be unique to the bilateral subiculum in female older adults.Support or Funding InformationThis work was supported by NIH grant R00 AG036845 (Schon), R21 AG049968 (Schon), and the BU Clinical and Translational Science Institute (1UL1TR001430).
Antioxidant and Anti‐inflammatory Activities of Methanolic Fraction from Native Mexican Avocado Seed Oil
Authors: Zavala-Guerrero Baruc , Hernández-García Alejandra , Torres-Martínez Rafael , Meléndez-Herrera Esperanza , Ríos-Chávez Patricia , Ochoa-Zarzosa Alejandra , López-Meza Joel E. , Saavedra-Molina Alfredo , Salgado-Garciglia Rafael 
Published: April 2020

Avocado fruit oil (Persea americana), mainly cultivar Hass, has excellent medicinal properties as antioxidant and anti‐inflammatory activities. However, these properties have not been evaluated in the seed oil of the native Mexican avocado (P. americana var. drymifolia). This study investigated the antioxidant and anti‐inflammatory activity of native Mexican avocado seed oil and the methanolic fraction. Seed oil was obtained with hexane by the Soxhlet method, which was extracted liquid‐liquid to obtain the methanolic fraction. In vitro antioxidant was examined with three radical scavenging methods (ABTS, DPPH and TAC) at 1 mg/mL, and IC50 was determined. Although the oil seed presented high percentage of antioxidant activity in a range of 90.5 to 91.38% with in vitro methods, the highest antioxidant activity was shown by methanolic fraction (99.7%) with ABTS method, presenting an IC50 of 0.035 mg/mL. Anti‐inflammatory activity of oil seed and methanolic fraction (0.1, 1 and 10 mg/kg of body weight) was estimated by measuring the paw edemathickness by carrageenan‐induced paw edema model in male Wistar albino rats (400 g), and compared to Ibuprofen (25 mg/kg of body weight), with topical and oral administration (50 μL) dissolved in DMSO 5%. Control animals received an equal volume of vehicle. Edema was induced with 1% carrageenan to all the groups after four hour of treatments, and paw thickness was checked at 1, 2, 3, 4, and 8 h. With topical administration of 10 mg/kg, the highest anti‐inflammatory effect was observed at 8 h, decreasing by 70.8% and 72.28% in paw thickness with oil seed and methanolic fraction, respectively. This anti‐inflammatory activity was 1.8 times more than Ibuprofen effect. At 8 h, the anti‐inflammatory activity with oral administration of 10 mg/kg of oil seed and methanolic fraction (by 28 days), was similar than with topical administration of oil seed (68.6%) and less than that methanolic fraction (46.69%), although these values were higher than Ibuprofen (39.61%). It shows a direct relationship between antioxidant and anti‐inflammatory activities of methanolic fraction from native Mexican avocado seed oil.Support or Funding InformationFunding from CIC‐UMSNH (2.10 to RSG).
Dynamics of Acetyl Homeostasis in Bacillus subtilis
Authors: Best Brian , Reverdy Alicyn , Chai Yunrong 
Published: April 2020

Bacillus subtilis biofilms are effective models for studying prokaryotic multicellular systems. These biofilms, multicellular bacterial communities encased in a protective polysaccharide and protein matrix, are associated with several bacterial and chronic infections but can also serve beneficial purposes in agriculture and wastewater treatment. Recent investigation into post‐translational protein modification in bacteria has elucidated important regulatory mechanisms for growth and biofilm formation. Protein acetylation has been observed to regulate bacterial multicellularity, and it is closely linked to cellular metabolism by using acetyl metabolites as donors of acetyl groups. The goal of this study is to examine the role of protein lysine acetylation as a regulatory mechanism for metabolism B. subtilis. We hypothesize that bacteria use acetylation as a buffering mechanism for acetyl metabolites to balance levels and prevent metabolite toxicity by increasing acetylation during times of high acetyl metabolite levels and deacetylating proteins to restore metabolites during times of low levels. Wild type bacteria as well as knockout mutants affecting protein acetylation and the carbon overflow pathway are grown in biofilm‐inducing minimal media, and cell and supernatant samples are collected at various ODs. Acetyl‐CoA, acetyl‐phosphate, and acetate levels over the course of growth are measured using fluorometric and colorimetric metabolite test level kits. Dynamics of global lysine acetylation levels are also measured by an anti‐acetyl lysine Western blot. Work so far has focused primarily on optimizing and troubleshooting metabolite assay kits by modifying growth and sample preparation conditions. Acetate dynamics have been measured for the wild type bacteria, showing a continuous secretion of acetate into the supernatant throughout exponential growth. This result is expected, as rapid growth should coincide with continuous utilization of the carbon overflow pathway. Initial Western blots show increased acetylation in the ΔackAΔacuCΔsrtN triple knockout mutant, which is expected due to a buildup of acetyl phosphate and inhibition of deacetylase activity. Future research will also focus on analyzing mutated genes in Δpta suppressor mutants to uncover genes related to acetyl‐CoA‐mediated cell death. Findings from this study will promote the understanding of the regulatory mechanisms behind biofilm formation and potentially uncover novel information about bacterial survival strategies and programmed cell death.Support or Funding InformationThis project was funded by grants from the National Science Foundation, the Northeastern University Honors Program, and the Northeastern University Office of Undergraduate Research and Fellowships.
Regulation of the chaperone‐mediated autophagy receptor LAMP2A by DYNC1LI2 in cystinosis
Authors: Rahman Farhana D. , Johnson Jennifer L. , Catz Sergio D. 
Published: April 2020

The dynein motor protein complex is required for retrograde transport but the specific functions of the intermediate and light chains that form the cargo‐binding complex are not elucidated and the importance of individual subunits in the maintenance of cellular homeostasis is unknown. Cystinosis is a lysosomal storage disorder caused by the accumulation of the amino acid cystine due to genetic defects in the CTNS gene, which encodes cystinosin, the lysosomal cystine transporter. Increased levels of intra‐lysosomal cystine lead to cell malfunction, which is especially manifested in the kidney epithelial proximal tubule cells (PTCs). Many cellular defects in cystinosis are independent of lysosomal overload, suggesting that cystinosin regulates cellular processes independently of its role as a cystine transporter. We showed that cystinotic cells (Ctns−/−) are characterized by vesicular transport defects, increased endoplasmic reticulum (ER) stress and susceptibility to oxidative stress. Here, using a mRNA array and immunoblot assays, we show that the dynein subunit, intermediate chain 2 (DYNC1LI2) is downregulated in cystinotic cells. Reconstitution of the expression of DYNC1LI2 in Ctns−/− fibroblasts re‐established endolysosomal dynamics quantified by Total Internal Reflection Fluorescence microscopy (TIRFM). Rescue of vesicular trafficking by DYNC1LI2 correlated with decreased ER stress manifested as decreased levels of the chaperone Grp78 in cystinotic cells. Mitochondrial fragmentation in cystinotic fibroblasts was also reduced by DYNC1LI2 expression. Survival of cystinotic cells to oxidative stress insult was increased by DYNC1LI2 but not by its paralog DYNC1LI1, which also failed to reestablish endolysosomal trafficking, or to decrease ER stress levels and mitochondrial fragmentation. Cystinotic (CTNS‐KO) PTCs, generated using CRISPR‐Cas9, showed defective endolysosomal trafficking and decreased expression of the Rab‐GTPase Rab11 carrier of the chaperone‐mediated autophagy receptor LAMP2A and the endocytic receptor megalin, both mislocalized in cystinosis. Restoring DYNC1LI2 expression rescued the localization of LAMP2A and restored the expression of megalin at the plasma membrane of CTNS‐KO cells. Expression of GFP‐DYNC1LI2 failed to rescue phenotypes in cystinotic cells (Ctns−/−) when co‐expressed with dominant negative (DN) RAB7/RAB11 but not DN‐Rab5 and in correlation with this finding, TR‐FRET assays show that DYNC1LI2 associates with RILP, a RAB7 effector and Rab11‐FIP4, a Rab11 effector. The rescue of the increased ER stress phenotype by DYNC1LI2 in cystinotic cells was blocked by downregulation of LAMP2A expression. Our results suggest that DYNC1LI2 reconstitution improves cellular homeostasis in a LAMP2A‐dependent manner highlighting DYNC1LI2 as a possible target molecule to improve cellular function in cystinosis.Support or Funding InformationNIHCRF
Effects of in‐vitro exercise‐induced endothelial shear stress on adhesion molecule gene expression
Authors: Conde Daniel , Gomez Manuel , Garcia Mario , Morales-Acuna Francisco , Gurovich Alvaro 
Published: April 2020

BackgroundExercise‐Induced Shear Stress (ESS) is characterized as a mechanical stimulus effecting cellular morphology and physiology. Varying ESS intensity elicit different response mechanisms through cellular signaling pathways. Higher intensity ESS enhances the expression of genes involved in protection against atherosclerosis. Adhesion molecules expression is common in atherosclerosis. Therefore, the purpose of this study was to determine the effects of different intensities of pulsatile ESS on vascular cell adhesion molecule‐1 (VCAM1) and intercellular adhesion molecule (ICAM1) gene expression.MethodsCommercially available human carotid artery endothelial cells (Sigma Aldrich) were cultured until 95–100% confluence and then exposed to pulsatile resting ESS (18 dynes/cm2) for 5 hours, followed by 1 hour low‐intensity ESS (35 dynes/cm2), or high‐intensity ESS (80 dynes/cm2) on parallel fluidic units (Ibidi, USA). Ibidi Pump Control Software (version 1.5.4, Ibidi, USA) was used to control shear stress intensity. mRNA was extracted and expression of VCAM1 and ICAM1 was assessed using qRT‐PCR. Samples were run in Changes in gene expression were calculated using the ΔΔ‐CT method, using GAPDH as the normalizing control gene. One‐way ANOVA was used to asses statistically significant differences (p < 0.05) using Prism version 8 (Graphpad).ResultsThe mRNA expression of VCAM1 and ICAM1 significantly increased (p <0.01). 6 and 8 folds respectively after exposure to low‐intensity ESS. Furthermore, high‐intensity ESS did not significantly increased the expression of VCAM1 and ICAM1.ConclusionLow‐intensity pulsatile exercise‐induced shear stress improves endothelial function in‐vitro through the increase in adhesion molecule’s gene expression.
Collaborative Exams to Promote Significant Learning in University Students in the Subjects of Cell Biology and Biochemistry
Authors: Arroyo Ana Gabriela Campos , Chávez Ricardo Adolfo Manivel , Flores Benjamin Rogelio Hernandez , Matías Flora María Cabrera 
Published: April 2020

Some teachers and researchers share the concern that one of the main obstacles involved in learning theoretical subjects, such as Mathematics, Physics, Chemistry or Biological Sciences, is the little practical sense that the student sees in them. Also, at the time of evaluation, there is a great concern about the amount of information that must be understood or retained generating anxiety, stress, confusion, among other factors. Therefore, it is important to create collaborative learning strategies that encourage student interactions, promoting peer education to achieve meaningful learning.ObjectiveKnow if collaborative exams promote significant learning in the subjects of Cell Biology and Biochemistry.Materials and methods107 university students from two biology and two biochemistry groups were considered. During a semester the subjects were taught following the programmatic content of each one, the subjects were biased, and exercises were applied between pairs of review, in addition 3 exams were applied collaboratively (in pairs or teams of 3). At the end of the semester, an adapted survey by Stokes, J. (2019) was applied, with questions aimed at assessing perceived learning, knowledge retention, peer‐to‐peer teaching experience and feelings towards group work.Results94.9% of the students stated that they like to take collaborative exams, 91% consider collaborative exams to be a valuable learning activity and 92.3% mention that they helped them retain knowledge due to the interaction generated in the Time to decide the correct answer.ConclusionsCollaborative exams are a peer learning strategy that can lead to meaningful learning, as well as helping to retain knowledge in subjects that are theoretical or even theoretical practical, improving their academic performance.Support or Funding InformationResearch supported and endorsed by the Michoacana University of San Nicolás of Hidalgo
Regenerative properties of the humerus bone in the absence of Stat3
Authors: Lopez Noah , Rigueur Diana , Lyons Karen 
Published: April 2020

The Interleukin‐6/STAT3 (IL‐6/STAT3) signaling pathway is essential for proper immune response to invading pathogens and viral infections. This signaling pathway has also been greatly investigated in cancer. Moreover, STAT3 has high implications as a therapeutic target for rheumatoid and osteo‐arthritis. Recent literature has found that the IL‐6/STAT3 signaling pathway plays an imperative role in the development of cartilage and bone. However, the direct role and the downstream effectors of STAT3 signaling have not been clearly delineated. Through skeletal preparations, X‐ray micrographs, and histology, our data show that conditional loss of Stat3 in mouse cartilage, via the Col2‐Cre driver, is essential for proper growth plate formation in the forelimbs of the skeleton. Furthermore, loss of STAT3 results in spontaneous bone fractures in the humerus. Interestingly, these severe fractures repair in adulthood, indicating an untapped mechanism for regeneration in bone. These studies will elucidate the imperative role the Stat3‐mediated pathway plays in modulating regeneration of the humerus during endogenous development and repair.Support or Funding InformationNIH R01 80094
Antioxidant and Anti‐inflammatory Effects of the Methanolic Extract of Potentilla indica Fruits
Authors: Sereno-Villaseñor Luis , Hernández-García Alejandra , Torres-Martínez Rafael , Meléndez-Herrera Esperanza , Manzo-Avalos Salvador , Martínez-Flores Héctor Eduardo , Saavedra-Molina Alfredo , Salgado-Garciglia Rafael 
Published: April 2020

Potentilla indica (Jacks.) Th. Wolf (Rosaceae) also known as mock strawberry, to which medicinal properties are attributed related to oxidative stress and chronic inflammation. A methanolic extract was obtained from the mature fruits of P. indica, and methanolic and chloroformic fractions of the extract were obtained by liquid‐liquid fractionation. The chloroformic fraction (1 mg/mL) presented the highest antioxidant activity by in vitro methods, 67.90% (TAC), 67.25% (DPPH) and 44.51% (ABTS). The anti‐inflammatory activity was tested using the carrageenan‐induced paw edema model in male Wistar albino rats (400 g). Ibuprofen was used as standard drug at concentration of 25 mg/kg of body weight. The methanolic extract and chloroformic fraction (dissolved in DMSO 5%) were administered topically and orally (by 28 days) at doses of 0.1, 1 and 10 mg/kg of body weight (50 μL). Control animals received an equal volume of vehicle. Edema was induced with 1% carrageenan to all the groups after four hour of treatments, and paw thickness was checked at 1, 2, 3, 4, and 8 h. Topical administration of the chloroformic fraction (1 mg/kg) decreased by 77.7% in paw thickness, and with oral administration decreased by 72% in paw thickness. The chloroformic fraction of methanolic extract of P. indica fruits had a high antioxidant activity and significantly decreased the inflammatory reactions induced by carrageenan.Support or Funding InformationSupport grant from CIC‐UMSNH (2.10 to RSG).
Chromatin Immunoprecipitation in Native Budding Yeast (Saccharomyces cerevisiae) Using Photo‐Crosslinking Unnatural Amino Acids
Authors: Brown Alon , Wilkins Bryan 
Published: April 2020

Exploiting an expanded genetic code in yeast, we can site‐specifically encode unnatural amino acids into the native chromatin landscape of the living cell. Utilizing the UV‐activated photo‐crosslinking amino acid, p‐benzoylphenylalanine (pBPA), we can covalently trap protein‐protein interactions when contacts between proteins are made within binding distances of ~ 0.4 nm. We have mapped the RSC remodeler complex protein, Sth1, to the nucleosome and shown that its binding is regulated by posttranslational modifications, including acetylation and SUMOylation. RSC has been linked to promoter sites and we want to further our binding map with an understanding of its occupancy across the genome. To map the loci of binding sites we use a double IP chromatin immunoprecipitation (ChIP) technique that utilizes the power of in vivo protein‐protein crosslinking from histones. Histones are well associated with DNA and efficient targets for ChIP analysis; therefore, we propose that if the histone protein is first crosslinked to a nucleosomal protein target, that the histone can be initially precipitated in tandem with its crosslinked protein and associated DNA fragments. The target protein can then be further precipitated to purify DNA, via its interaction with the histone. Our first goal was to establish histone occupancy of pBPA‐containing histones. Using ChIP, we were able to isolate DNA from both wild type and mutant histones where we can achieve a quantitate analysis of the difference with qPCR. Building on this we will move to a double IP system to determine Sth1 occupancy. This work aims to establish a novel approach in ChIP targeting of proteins that are difficult to analyze due to more transient interactions at the nucleosomal core.Support or Funding InformationNIH R15 grant
The Effects of Prolonged Mechanical Ventilation on Structural and Material Properties of Diaphragm Arterioles
Authors: Horn Andrew Gary , Kunkel Olivia Nicole , Baumfalk Dryden Ray , Simon Mikaela Elizabeth , Schulze Kiana Marie , Bruells Christian S. , Poole David C. , Behnke Bradley Jon 
Published: April 2020

IntroductionIn skeletal muscle arterioles, cellular and vasoactive responses are influenced by the physiochemical milieu of the surrounding tissue. Understanding the mechanical properties of the blood vessel wall yields insight into vascular function in health and disease. In blood vessels, the endothelium mediates flow‐dependent vasodilation and contributes to the regulation of arterial mechanics. Prolonged mechanical ventilation (MV)(>6 h) results in large, time‐dependent reductions in diaphragmatic blood flow and impaired endothelium‐dependent (and ‐independent) vasodilation of first‐order (1A) medial costal diaphragm arterioles. The purpose of this investigation was to determine if the severe reductions in diaphragmatic blood flow (and shear‐stress) with MV impair the structural and material properties (i.e. increased stress/stretch relation and/or circumferential stretch) of 1A arterioles from the medial costal diaphragm.MethodsFemale Sprague‐Dawley rats (~5 mo) were randomly divided into two groups, spontaneous breathing (SB, n = 6) and prolonged MV (6 h MV, n =5). Following SB and 6 h MV, 1A medial costal diaphragm arterioles (~200 μm diameter, ~2 mm in length) were isolated and cannulated. After cannulation, vessels were adjusted to a fixed length (L, 1.5 mm) and pressurized. Vessels that exhibited no leaks were subjected to a step‐wise passive‐pressure diameter test (0–140 cmH2O) in calcium‐free Ringer’s solution, at a single fixed axial length (L). Inner diameter (μm) and wall thickness (μm) were measured at each pressure step and used to calculate wall: lumen ratio, incremental distensibility (%/mmHg), Cauchy‐stress (μ), and circumferential stretch (λθ).ResultsFollowing 6 h MV, in the undeformed condition (0 mmHg) the wall: lumen ratio was significantly smaller compared to SB (1.04 ±0.21vs. 2.60 ±0.40; p<0.05). There were no differences in incremental distensibility (%/mmHg) and the stress/stretch (μvs λθ) relation between groups (p>0.05). At every pressure step, circumferential stretch (λθ; undeformed radius (r)/current deformed radius (R)) was significantly increased with 6 h MV versus SB (p<0.05).ConclusionDespite no change in the distensibility and structural behavior (stress/stretch) of resistance vessels from the medial costal diaphragm, prolonged MV resulted in altered material properties (i.e. elevated circumferential stretch (λθ)) of medial costal diaphragm arterioles. Increased circumferential stretch can enhance superoxide generation in the endothelium and vascular smooth muscle cells. Therefore, elevated circumferential stretch of 1A diaphragm arterioles in combination with the severe reductions in blood flow may, in part, explain the previously demonstrated vascular dysfunction in the diaphragm following MV.Support or Funding InformationSupported by: NIH HL137156‐01A1