bluuebunny/crossref_metadata_2025_split huggingface dataset:
Astaxanthin, a xanthophyll carotenoid, inhibited and reversed the activation of mouse primary hepatic stellate cells via the modulation of histone deacetylases (39.1)
Authors: Yang Yue , Lee Ji‐young 
Published: June 2021

Activation of hepatic stellate cells (HSC) is a major event in the development of liver fibrosis. Previously, we have shown that astaxanthin (ASTX), a xanthophyll carotenoid, has a potent anti‐fibrogenic effect in LX‐2 cells, a human HSC cell line. In this study, we investigated if ASTX prevents the activation of quiescent HSC and also facilitates the deactivation of activated, myofibroblast‐like HSC using mouse primary HSC. Incubation of ASTX with quiescent HSC inhibited their activation as evidenced by decreased loss of intracellular lipid droplets, and repressed expression of HSC activation markers, such as α smooth muscle actin (αSMA), at mRNA and protein levels. Moreover, in activated HSC, the addition of ASTX for 2 or 4 d resulted in reappearance of lipid droplets and decreased αSMA expression, suggesting that ASTX reversed HSC activation. As histone deacetylases (HDAC) have a potential role in HSC activation, we screened the effect of ASTX on the expression of all 11 classical HDAC isoforms. Notably, HDAC9 expression was significantly elevated during HSC activation, which was markedly attenuated by ASTX. Taken together, ASTX not only prevented the activation of quiescent HSC but also reversed morphological changes and repressed αSMA expression in activated HSC, possibly via the modulation of HDAC9 expression. Therefore, ASTX may be used for the prevention of liver fibrosis.Grant Funding Source: USDA AFRI 2012‐67018‐19290
Development and assessment of group problem solving exercises to advance student reasoning skills (531.17)
Authors: Beedle Aaron 
Published: June 2021

The development and application of reasoning skills in scientific disciplines is important for student success in undergraduate education. To promote these skills in undergraduates of the new Bachelor in Pharmaceutical Sciences program at the University of Georgia, the required didactic course in human physiology was designed to incorporate six small group problem solving sessions dispersed throughout the course. Sessions were designed for groups of four to five students and used current course topics as a basis for critical thinking exercises. Students were assigned to random groups to work through a series of quests in content areas such as muscle metabolism, the baroreceptor reflex, drug absorption in the GI tract, and autoimmune endocrine disorders. Quests were designed to address skills such as identifying a problem/question, evaluating sources of medical information (bias), understanding limitations of individual studies, and logical application of homeostasis and negative feedback. Group interactions were reinforced by providing unique materials or tasks to individual group members that were necessary for completion of the exercise. Concepts from group sessions were reinforced with individual reflective homework assignments. The efficacy of group sessions was evaluated with pre‐ and post‐course assessments of reasoning skills in the inaugural class of fifteen students. Overall, student responses to problem solving sessions were positive; however, application of the exercises in a larger student population is necessary to better determine their impact on reasoning skills.Grant Funding Source: Supported by the Lilly Teaching Fellow program, Univ. of Georgia Center for Teaching and Learning
The dynamic chromatin configuration during pituitary differentiation (562.1)
Authors: Ho Yugong , Cooke Nancy , Liebhaber Stephen 
Published: June 2021

Pit‐1, a pituitary specific POU homeodomain transcription factor, plays an essential role in the process of differentiation of anterior pituitary. Abolishing the expression of Pit‐1 results in the combined block in the differentiation of somatotropes, lactotropes, and thyrotropes in anterior pituitary. Prior studies have revealed that the initial activation of Pit‐1 at embryonic day 14 (E14) in the developing mouse pituitary. This activation is mediated by the binding of transcription factor Atbf1 at the ‘early enhancer’ of Pit‐1, located ‐5.8 kb upstream of the Pit‐1 promoter, and by concurrent binding of Prop‐1 at the promoter. The maintenance phase of Pit‐1 expression is initiated at E16.5 by an auto‐regulatory mechanism in which Pit‐1 binds to its own promoter and to a distal enhancer (‘late enhancer’) located 10 kb upstream of the Pit‐1 promoter. Despite the identification of these regulatory elements, the accompanying changes in chromatin architecture at the Pit‐1 locus during the pituitary development remains undefined. In the current study, we investigate the chromatin configuration of the Pit‐1 locus at different developmental stages. We detect acetylation that is restricted to the early enhancer and the promoter at E14.5 while acetylation spreads throughout the entire locus at the adult stage. Our 3C assays reveal that the early enhancer is positioned proximal to the Pit‐1 promoter while in the maintenance phase is accompanied by a switch in the locus conformation, with positioning of the distal enhancer in proximity to the promoter. Furthermore, our studies suggest that the interaction between the distal enhancer and the promoter is mediated by Pit‐1 and CBP in differentiated pituitary. Taken together, our studies demonstrate that the regulation of Pit‐1 expression is accompanied by the dynamic alternation of the chromatin conformation during the pituitary differentiation and the chromatin architectures play important roles in activation and maintenance of gene expression.Grant Funding Source: Supported by University Research foundation of University of Pennsylvania
Biogenesis of mitochondrial metabolite carrier proteins in Trypanosoma brucei (574.1)
Authors: Smith Joseph , Chaudhuri Minu 
Published: June 2021

Trypanosoma brucei, a parasitic protozoan and the causative agent of human African trypanosomiasis, possesses a single mitochondrion in which many essential metabolic processes occur. These biological processes require various metabolites to be fluxed in and out of the mitochondrial matrix by specialized transporters called metabolite carrier proteins (MCPs). Metabolite carriers are encoded in the nuclear genome and post‐translationally imported into mitochondria. In yeast and humans, there is a dedicated inner membrane protein translocase, TIM22, and soluble small Tim proteins of the intermembrane space, which are involved in MCP biogenesis. Trypanosoma brucei possesses a large family of MCPs; however, the parasite appears to lack the TIM22 translocase in its entirety. A few putative homologs of soluble Tims have been identified in this parasite, although functions of these proteins are not elucidated. Here, we begin to characterize the T. brucei homologs of the small Tim proteins (TbTim9, TbTim10, and TbTim13/8 that shows similarity to both Tim8 and Tim13 in higher eukaryotes) and their possible involvement in metabolite carrier import. We found that TbTim9, TbTim10, and TbTim13/8 are expressed and localized in mitochondria in T. brucei. Knockdown of TbTim9 and TbTim10 individually decreased cell growth, while knockdown of TbTim13/8 ceased cell growth within 5 days. Reducing the expression of these proteins also reduced the steady‐state levels of the metabolite carrier protein, TbMCP5, suggesting that these TbTims are likely involved in MCP biogenesis. Further experiments are now ongoing to understand the roles of TbTims in the import of TbMCP5 into the mitochondrial inner membrane and also to identify the inner membrane translocase involved in this process.Grant Funding Source: Supported by 2SC1GM081146 and 2R25GM059994
The study of the impact of genetic polymorphism of aromatase (CYP19) enzyme and the susceptibility to polycystic ovary syndrome (575.5)
Authors: Hemimi Neveen , Shaafie Ishtiyaq , Alshawa Haya 
Published: June 2021

Abstract
Background: Aromatase is a key steroidogenic enzyme that catalyzes the conversion of androgens to estrogen. Several studies reported the association of the SNP 50 (rs2414096) in aromatase enzyme with hyperandrogenism.Aim: To investigate the association of genetic polymorphism of aromatase enzyme with polycystic ovary syndrome (PCOS).Material and Method: The study consisted of 62 women diagnosed with PCOS and 60 healthy women as a control group. Individuals were genotyped for rs2414096 of aromatase enzyme by using polymerase chain reaction‐ restriction fragment length polymorphism. Statistical analysis was done by SPSS program.Results: Frequency of (GG) and (GA&AA) genotypes were 64.5% and 35.5% in PCOS group compared to 76.7% and 23.3% in control group. Statistical analysis demonstrated that carriers of (GA&AA) genotype were at higher risk for PCOS compared to carriers of (GG) genotype (OR= 1.81, 95%CI= 0.8‐3.99). Carrier of A allele were also at higher risk of PCOS compared to carrier of G allele (OR=1.3, 95% CI= 0.7‐ 2.3).Conclusion: Polymorphism of rs 2414096 in CYP19 is associated with the pathogenesis of PCOS. Key word: Aromatase, Polymorphism, PCOS.
Single molecule analysis reveals self assembly and nanoscale segregation of two distinct cavin subcomplexes on caveolae (602.1)
Authors: Gambin Yann , Sierecki Emma , Polinkovsky Mark , Alexandrov Kirill , Parton Robert 
Published: June 2021

In mammalian cells three closely related cavin proteins cooperate with the scaffolding protein caveolin to form membrane invaginations known as caveolae.Here we have developed new methods that allow reconstitution of the cavin complex and performed a quantitative assessment of cavin complex formation. We use single molecule fluorescence for its proven ability to directly observe multiple populations and quantify interactions in complex mixtures. These techniques are especially well suited for the study of coat proteins and have been used to study the mechanisms of clathrin assembly/disassembly. Those studies required labeling of recombinantly expressed purified proteins, which in the case of the cavin complex is difficult. We have taken an alternative approach to obtain the stoichiometry of the cavin complex and the interactions between the members of the cavin family (cavin1, cavin2, cavin3) directly from cell extracts. Instead of relying on organic dyes, we could perform the full quantitative analysis using genetically encoded fluorophores, shortcutting purification steps.We show that up to 50 cavins associate on a caveola. However, rather than forming a single coat complex containing the three cavin family members, single molecule analysis reveals an exquisite specificity of interactions between cavin1, cavin2 and cavin3. We could observe fascinating behavior of the cavin members, with exquisite segregation of interactors and defined stoichiometries in mixed oligomers. Changes in membrane tension can flatten the caveolae, causing the release of the cavin coat and its disassembly into separate cavin1‐cavin2 and cavin1‐cavin3 subcomplexes. Each of these subcomplexes contain 9±2 cavin molecules and appear to be the building blocks of the caveolar coat. High resolution immunoelectron microscopy suggests a remarkable nanoscale organization of these separate subcomplexes, forming individual striations on the surface of caveolae.
Gtr1‐Gtr2, Ego1‐Ego3 and Vam6‐independent cytoplasmic Gln3 sequestration in conditions of nitrogen excess (609.17)
Authors: Cooper Terrance , Tate Jennifer , Rai Rajendra , Georis Isabelle , Dubois Evelyne 
Published: June 2021

The Gtr1/2, Ego1/3 complexes and Vam6 have been reported to be required for TorC1 kinase activation. In turn, activated TorC1 is accepted to be required for cytoplasmic Gln3 sequestration based on the observations that: (i) a Tor1‐Gln3 interaction is required for high level cytoplasmic Gln3 sequestration in nitrogen excess and (ii) rapamycin treatment elicits cytoplasmic to nuclear Gln3 relocation. These correlations lead to the a priori prediction that Gtr1/2, Ego1/3 and Vam6 should also be similarly required for downstream cytoplasmic Gln3 sequestration when cells are cultured in excess nitrogen. To test this hypothesis, we individually deleted the genes encoding each of the above proteins and determined whether the Gtr‐Ego complexes were required for cytoplasmic Gln3 sequestration in nitrogen rich medium. In every case cytoplasmic Gln3 sequestration occurred to the same degree in the deletion mutants as in wild type. These data indicate that either cytoplasmic Gln3 sequestration occurs in response to a TorC1‐independent regulatory pathway and/or alternatively that TorC1 activation can occur via both Gtr1/2‐Ego1/3‐Vam6‐dependent and ‐independent regulatory pathways.Grant Funding Source: NIH GM‐35642; FRFC 2.4547.11
Control of bacterial chemotaxis by heme nitric oxide/oxygen proteins (614.2)
Authors: Hespen Charles , Marletta Michael 
Published: June 2021

Hemoprotein gas sensors are integral components in the cellular machinery to recognize and rapidly respond to dynamic changes in redox state and the concentration of reactive gases. Heme‐Nitric oxide/Oxygen sensing (H‐NOX) proteins, found in both eukaryotes and bacteria, respond to NO in facultative aerobic bacteria, and regulate biofilm formation through the control of a complex two‐component signaling network. H‐NOX proteins are also found in obligate anaerobic bacteria, predominantly Clostridia, and are fused to Methyl‐accepting Chemotaxis Proteins (MCPs). MCP domains control the chemotaxis‐signaling pathway, which guides bacteria toward beneficial molecules (attractants) and away from harmful molecules (repellents). Obligate anaerobe H‐NOXs contain a conserved H‐bonding network associated with the formation of a stable O2 complex. Because NO and O2 are both toxic to obligate anaerobes, the H‐NOX‐MCP likely senses one or both of these gases and activates a repellent response in bacteria. A gas sensing chemoreceptor has not yet been identified in Clostridia, a class of organisms whose ability to rapidly avoid increasing concentrations of O2 is vital for survival. To characterize how gases affect the H‐NOX‐MCP's control of chemotaxis, the chemotaxis pathway of Clostridium sporogenes has been reconstituted in vitro. Changes in activity of the chemotaxis histidine kinase, CheA, were measured in different H‐NOX‐MCP heme ligation states.Grant Funding Source: Supported by NIH Ruth L. Kirchstein NRSA
Identifying and refining threshold concepts for biochemistry using a community of faculty and students (618.1)
Authors: Loertscher Jennifer , Minderhout Vicky , Green David , Lewis Jennifer 
Published: June 2021

Threshold concepts are concepts that when mastered, represent a transformed understanding of a discipline, without which the learner cannot progress. We have undertaken a process involving over 75 faculty members and 40 undergraduate students to identify a working list of threshold concepts for biochemistry. The process of identifying threshold concepts for biochemistry was modeled on extensive work related to threshold concepts across a range of disciplines. Three major sources of information were used to identify threshold concepts for biochemistry: faculty workshops, student interviews, and existing data from the literature and other sources. We will report on use of an iterative process to identify three to five concepts to be the focus of future curriculum and assessment materials development. The concepts are likely to relate to foundational ideas from chemistry yet be situated in essential biochemical contexts. Candidate concepts relate to equilibrium, inter/intramolecular interactions, and individual versus populations of molecules. The finalized working list is not intended to be exhaustive, but rather is meant to identify a subset of threshold concepts for biochemistry for which instructional and assessment tools for undergraduate biochemistry will be developed.Grant Funding Source: NSF‐DUE 1224868
Use of student interviews to identify and refine threshold concepts for biochemistry (618.23)
Authors: Lin Sara , Loertscher Jennifer , Minderhout Vicky , Green David , Lewis Jennifer 
Published: June 2021

Threshold concepts are fundamental concepts that require mastering in order to progress towards a deeper understanding of a discipline. Despite their importance in teaching and curriculum reform efforts, threshold concepts have not yet been identified for biochemistry. Using an iterative approach involving over 75 faculty members and over 40 students from diverse institutions nationwide, we have developed a list of candidate threshold concepts, which will inform the design of new active learning materials and assessment tools. Student interviews, conducted with biochemistry and organic chemistry students from five different institutions, were essential in refining the pilot list developed by faculty. Each focus group interview probed student understanding of two of the three candidate threshold concepts: dynamic equilibrium, intra‐ and intermolecular interactions, and individual versus populations of molecules. Analysis of interview transcripts revealed wide variability in student understanding of these concepts that could be due to differences in major, prerequisite coursework and/or amount of biochemistry coursework completed. Despite the variability, trends were observed including an inability to articulate the meaning of steady state in a biological context, difficulty articulating the basis of intermolecular interactions in any context, and recognition that moving between thinking about individual versus populations of molecules is an important and challenging part of learning biochemistry.Grant Funding Source: National Science Foundation NSF‐DUE 1224868
The relative influence of prepregnancy weight and gestational weight gain on offspring birth size in Vietnam (620.7)
Authors: Young Melissa , Nguyen Phuong Hong , Addo O.Yaw , Hao Wei , Nguyen Hieu , Pham Hoa , Truong Truong V , Nguyen Son , Martorell Reynaldo , Ramakrishnan Usha 
Published: June 2021

Maternal and child undernutrition remains an important public health problem. The objective of this research is to examine the relative influence of maternal prepregnancy weight (PPW) and gestational weight gain (GWG) on birth size for 971 singleton live births born to women who participated in a pre‐conceptional micronutrient supplementation trial in Vietnam. Adjusted generalized regression models were used to examine associations with birth weight, BW (mean + SD: 3054 + 400 g); small for gestational age, SGA (22%); and low birth weight, LBW (5%). A 1 SD increase in PPW was associated with a 226 g (95%CI: 220‐231) increase in BW. Similar and independent effects were observed for BW (226 g; 95%CI: 219 – 233) per SD increase in GWG. The relative impact of a 1 SD increase in PPW and GWG were similar for length (0.17 and 0.14 cm), head circumference (0.13 and 0.15 cm) and MUAC (0.15 and 0.14 cm) at birth, respectively. A 1 kg increase in PPW and GWG was also associated with a 9.4% and 9.5% reduction in the risk of delivering a SGA infant and 12% and 15% for LBW, respectively. Women with pre‐pregnancy BMI < 17 kg/m2 (moderate‐severe thinness) or in the lower tertile of GWG had 2.4 – 2.6 times the risk for SGA and 3.9 – 4.6 times the risk for LBW. These findings indicate that programs aimed at improving birth outcomes will have the greatest impact if they address maternal nutrition both before and during pregnancy.Grant Funding Source: Supported by the Micronutrient Initiative & the Mathile Institute for Advancement of Human Nutrition
Comparison of breast milk sodium‐potassium ratio, pro‐inflammatory cytokines, and somatic cell count as potential biomarkers of subclinical mastitis (623.21)
Authors: Wren Hilary , Li Chen , Solomons Noel , Chomat Anne Marie , Scott Marilyn , Koski Kristine 
Published: June 2021

Background: SCM is an asymptomatic inflammatory condition of the lactating breast associated with infant growth faltering. A breast milk Na/K ratio >0.6 is the current indicator for SCM whereas in cows SCC is considered the ‘gold standard’. Our objective was to determine if potential biomarkers of human SCM (SCC, pro‐inflammatory cytokines) were associated with Na/K ratio at two stages of lactation.Methods: Breast milk samples were collected from 53 lactating Mam‐Mayan women with infants < 45d (early lactation) and 52 with infants 4‐6mo (late lactation). Inductively Coupled Plasma Mass Spectrometry measured Na and K. Flow Cytometry was used to measure SCC. Luminex measured 3 pro‐inflammatory cytokines (IL‐6, IL‐8, TNF‐α).Results: One‐fifth had a breast milk Na/K ratio >0.6; an elevated Na/K ratio was more common in early lactation (26%) compared to later lactation (15%). By contrast, both IL‐8 (10.3 vs 38.3 pg/mL) and SCC (313K vs 457K cells/mL) were lower in early verses later lactation. The Na/K ratio was positively correlated with all 3 pro‐inflammatory cytokines in early lactation whereas only IL‐8 was associated in later lactation. SCC was not correlated with either Na/K ratio or pro‐inflammatory cytokines in either stage of lactation.Conclusion: Potential biomarkers of SCM vary by stage of lactation. Based on the Na/K ratio, SCM is more prevalent during early lactation. Results suggest that pro‐inflammatory cytokines may emerge as possible biomarkers and that SCC may not be a useful biomarker of SCM in lactating mothers.Grant Funding Source: McGill University International Mobility Award, NSERC
Isoflurane induces substrate‐dependent early mitochondrial PTP opening (648.13)
Authors: Agarwal Bhawana , Dash Ranjan , Bosnjak Zeijko , Stowe David , Camara Amadou 
Published: June 2021

The volatile anesthetic isoflurane (ISO) may increase permeability of mitochondria to protect against mitochondrial injury. Prolonged opening of the mitochondrial permeability transition pore (mPTP) inevitably causes mitochondrial demise, whereas transient mPTP opening may release accumulated Ca2+ from the matrix to avoid subsequent irreversible mPTP opening due to Ca2+ overload. To test if ISO alters mPTP opening, we isolated mitochondria from Wistar rat hearts to assess buffer Ca2+ uptake by Fura 4F. We found that: (a) ISO (1 mM) induced earlier mPTP opening by increasing Ca2+ uptake rate with succinate (SUC). (b) ISO did not alter mPTP opening but reduced Ca2+ uptake with pyruvate/malate. (c) 10 µM ryanodine or 10 nM imperatoxin A with SUC increased Ca2+ uptake and induced earlier mPTP opening; this suggests that ISO’s effects on mPTP may be due to increased conductance via mitochondrial ryanodine receptors (mRyR). We have patch‐clamped single mRyRs in mitoplasts. Our data infer indirectly that SUC substrate ‐dependent transient mPTP opening may be due to enhanced RyR Ca2+ uptake. Transient Ca2+ release could be a mechanism underlying ISO –induced cardiac protection in ischemia‐reperfusion injury.Grant Funding Source: P01‐GM066730, R01‐HL095122, R01‐HL089514