bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxin‐antitoxin systems: novel mechanisms of toxin activity and antitoxin inhibition
Authors: Page Rebecca , Peti Wolfgang 
Published: November 2023

Toxin‐antitoxin (TA) modules function as regulatory switches that allow bacteria to adapt to rapidly changing environments. Under conditions of unrestrained growth, these systems are repressed. However, under conditions of stress, these systems are activated, leading to growth arrest and dormancy. Their central role controlling bacterial growth has led to renewed efforts to understand the molecular basis of TA function in order to develop strategies to exploit these systems for societal benefit. The E. coli mqsR gene was originally discovered for its role in promoting biofilm formation and dormancy. During the past five years, we have used biochemistry and structural biology to show that mqsRA is a bona fide toxin‐antitoxin system, in which MqsR is ribonuclease (RNase) toxin, and MqsA is its cognate antitoxin. Unpublished results from our group now demonstrate that MqsR defines a new hybrid family of toxin RNases and that its MqsA antitoxin inhibits MqsR via a novel mechanism. Specifically, we are using NMR chemical shift mapping coupled with mutagenesis and biochemistry to identify the residues that mediate mRNA binding and cleavage and show that MqsR exhibits sequence specificity outside the primary GCU cleavage sequence. Furthermore, our work is revealing that MqsA inhibits MqsR activity via a completely novel mechanism for antitoxins; i.e. it potentially inhibits substrate binding by engaging loops outside the MqsR active site that are critical for the interaction with mRNA. Finally, we extending these studies to evolutionarily related families to elucidate the molecular basis of conservation and divergence of enzyme function in this family. Collectively, these studies are not only revealing that MqsRA defines a novel subfamily of TA systems but, more critically, also leading to the identification of the key molecular details that will allow these systems to be directed for societal benefit.Support or Funding InformationNSF‐CAREER award (MCB0952550) to RP.
HIF1α Activated Etv2 and Notch1 Signaling Biphasically Mediates ESC Differentiation to Arterial Endothelial Cells with Enhanced Sequestration in Ischemic Tissue
Authors: Hyun James , Tsang Kitman , Cheng Kwong , Vargas Micaela , Komarova Yulia , Mehta Dolly , Fukai Masuko , Rehman Jalees , Malik Asrar 
Published: November 2023

Endothelial progenitors derived from embryonic stem cells (ESCs) are an effective and attractive source to treat ischemic tissue. However, the molecular mechanisms mediating the generation of these beneficial cells and their regenerative capacity have not been well characterized. In this study, we demonstrate hypoxia is a critical environmental factor that doubles the number of VE‐cadherin+/CD31+ at the end of 7 days and produces arterial endothelial cells with great therapeutic potential. We determined hypoxia regulates both differentiation of ESCs to endothelial cells and their regenerative function. Initial hypoxic exposure, 1% O2, committed ESCs to endothelial lineage by upregulating the transcription factor Etv2 fivefold via Hif1α. Subsequently, prolonged hypoxia induced Notch signaling also via Hif1α, which specified arterial identity, marked by the increased expression of the arterial specific markers, Ephb2, Notch1, and Dll4. Transplantation of endothelial cells in myocardial infarction and hind limb models demonstrated hypoxia derived arterial endothelial cells conferred long‐term benefit and restored vascularity better than normoxia derived endothelial cells. Based on these findings, Hif1α plays a dual role in first specifying endothelial lineage via upregulation Etv2, and thereafter specifying for arterial lineage through Notch activation. Furthermore, hypoxia derived arterial endothelial cells are superior to normoxia derived endothelial cells in treating ischemic tissue.Support or Funding InformationNIH Lung and Pathobiology Training Program: NIHT32HL007829‐22
Structural Analysis of the 26S Proteasome Complex to Understand Its Function and Regulation
Authors: Huang Lan 
Published: November 2023

The ubiquitin‐proteasome system (UPS) represents the major pathway for regulated degradation of intracellular proteins in eukaryotes, which plays an important role in regulating many biological processes such as cell cycle progression, signal transduction and DNA repair. The 26S proteasome is the macromolecular machine responsible for ATP/ubiquitin dependent degradation, and is composed of at least 33 subunits that form two subcomplexes, 20S core particle and 19S regulatory particle. Disruption of proteasomal degradation has been implicated in many human diseases, and components in the UPS have become attractive therapeutic targets in recent years. Therefore, structural analysis of the human 26S proteasome complex will not only advance our understanding of its action and regulation mechanisms, but also will uncover potential targets for future cancer therapeutics. However, characterization of the 26S proteasome complex using conventional structural tools has been an extremely challenging task due to its dynamics and heterogeneity. Recently, cross‐linking mass spectrometry (XL‐MS) has emerged as a powerful and alternative structural tool to for studying protein‐protein interactions and elucidating architectures of protein complexes. In addition to capture protein‐protein interactions in cells, XL‐MS experiments allow the identification of cross‐linked peptides and define protein physical contacts at the amino‐acid level resolution. The information obtained can be used to derive protein interaction network topology and structural models of protein complexes. Although effective, XL‐MS studies have several inherent limitations. Here we present a novel cross‐linking mass spectrometry (XL‐MS) strategy based on our newly developed MS‐cleavable cross‐linking reagents and multistage tandem mass spectrometry to define protein‐protein interactions of the human 26S proteasome, especially as they occur in living cells. With this new approach, we have determined structural dynamics of the 26S proteasome and identified cross‐links between proteasome subunits and their interacting proteins. Our results have provided structural details on how protein‐protein interactions are involved in modulating proteasomal functions. The methodology presented here can be adopted for the study of other protein complexes in vitro and in vivo.Support or Funding InformationThis work is supported by NIH RO1GM074830 to L.H, and R01GM106003 to L.H. and S. R..
Effective Transfer of Nutritional Messages to Caregivers by Health Service Providers Trained in Counseling in Two Poor Districts of the Lambayeque Region, Peru
Authors: Charron Myriam B. , Marquis Grace S. , Creed‐Kanashiro Hilary M. , Martinez Rosario Bartolini , Sernaqué Cindy Castro 
Published: November 2023

Suboptimal infant and young child feeding practices contribute to poor nutrition outcomes. The 2015 Peru Demographic Health Survey reported that 49% of infants 6–8 months did not consume meats, poultry, fish, or eggs and 36% received fewer than three food categories. These inadequate feeding practices contribute to the high rates of anemia (43.5% of children 6 – 35 months). In response, the Lambayeque regional government funded a train‐the‐trainer initiative in the four poorest districts of the region to improve the skills of health service professionals (HP) in effective nutrition education counselling. The objectives of the present study were to evaluate how the training was currently applied in counselling by HP and to identify influential factors on effective transfer of improved nutrition practices to caregivers. Of particular interest was to examine interpersonal relationships between HP and caregivers.Data were collected in six health establishments in two of the four selected Lambayeque districts. We completed in‐depth interviews with 5 HP, and 34 exit interviews with caregivers, of whom 7 gave in‐depth interviews and 5 who also permitted home observations. In addition, 29 direct participant observations of visits to the child growth and development monitoring program were conducted to observe the counselling.Counselling messages focused on how to use multi‐micronutrient powders and increase consumption of iron‐rich foods (e.g., liver, sangrecita). A majority of caregivers identified those same messages as the most important ones to assure their children's health. Interviews with caregivers and home observations indicated that nutritional messages (e.g., give more iron‐rich foods, give more legumes) were acceptable and feasible to achieve in the household. Learning materials (e.g., model plates) and group demonstration sessions facilitated caregiver comprehension, whereas caregivers' Quechua language was a barrier. Challenges that affected the continuity of good counselling in the health services were the frequent rotation of health service personnel and poor caregiver attendance. Lastly, beliefs or traditions prevented the adoption of some messages (e.g., duck is a cold meat, consuming animal blood (sangrecita) is comparable to consuming the animal's soul).Health professionals in the targeted districts used counselling skills demonstrated in the on‐going training and delivered the training's key nutrition messages. The HP made use of learning materials and used different delivery methods; caregivers understood the nutritional messages and applied them in their home. To conclude, HP also benefited from this on‐going initiative as they manifested a sense of satisfaction in what they had accomplished in improving children's health and nutritional status.Support or Funding InformationMcBurney Foundation
A novel FADS2 isoform isolated from milk fat globules suppresses FADS2 mediated Δ6‐desaturation of omega‐3 fatty acids
Authors: Kothapalli Kumar , Park Hui Gyu , Guo Xiaoxian , Sun Xuepeng , Zou James , Hyon Stephanie S , Qin Xia , Lawrence Peter , Ran‐Ressler Rinat R , Zhang Ji Yao , Gu Zhenglong , Brenna James Thomas 
Published: November 2023

IntroductionAlternative mRNA splicing is increasingly recognized as a modulator of protein structure and function. Here we report identification of a novel alternative transcript of fatty acid desaturase 2 (FADS2) and characterization of its function, discovered during the study of alternative transcripts in human milkfat globules (MFG).MethodsHuman breastmilk collected from a single donor was used to isolate MFG. The isolated MFG was used to extract total RNA and construction of mRNA‐sequencing library. The constructed library was sequenced using an Illumina HiSeq instrument operating in high output mode. Expression levels of evolutionary conserved FADSAT were measured using cDNA from MFG by semi‐quantitative RT‐PCR assay.ResultsA total of 52 million reads were sequenced, showing expression of 15605 transcripts. Classical fatty acid desaturase 2 (FADS2), which catalyzes the rate limiting step in PUFA synthesis, is moderately expressed. A novel FADS2 alternative transcript (FADS2AT2) with 386 amino acids was identified. When FADS2AT2 was transiently transfected to stable FADS2 MCF7 cells and incubated with omega‐3 fatty acid precursor 18:3n‐3, suppression of delta 6 desaturation (D6D) product 18:4n‐3 and its downstream 20:4n‐3 and 20:5n‐3 fatty acids were observed compared to control cells. No significant changes were observed when incubated with omega‐6 fatty acid precursor 18:2n‐6. FADS2, FADS2AT1 and 5 out of 8 known FADS3AT were expressed in MFG. FADS1, FADS3AT3, and FADS3AT5 are undetectable.ConclusionFADS2AT2 regulates noncatalytically classical FADS2 mediated Δ6‐desaturation of n‐3 but not n‐6 PUFA biosynthesis. This novel spliced isoform mediated interaction is the first molecular mechanism by which desaturation of one PUFA family but not the other is modulated.Support or Funding InformationAT007003
If a picture already tells a thousand words, how many more do we need to add?
Authors: Bretschneider Jochen , Rothman Zachary 
Published: November 2023

We review the unique opportunities that video production provides for teaching and learning, with a focus on storytelling using sounds, images, and yes, even (occasionally) words.Subject Matter Expertise is rooted in the written word and the public presentation, but contemporary tools and new methods of distribution require educators and experts to learn a new kind of media literacy.Innovate or perish. Communicate or disappear.We take the audience on a journey from written word to motion picture, using examples of our past video productions ‐ from the high production value 4K UBC Neuroanatomy Series to shorter, cost effective, more focused lessons on human anatomy shot with a smartphone. We show that video production is not only a necessary piece of the new learning ecosystem, but one that you can engage with directly using tools you might already have in your pocket. Engaging and thought provoking, this hands‐on session will create a small army of fledgling filmmakers.Support or Funding InformationNone
Maternal Hypercholesterolemia and Phytosterol Intervention on Oxysterol Concentrations in Newly‐Weaned ApoE Deficient Mice
Authors: Dumolt Jerad , Radhakrishnan Sandhya , Mathew Joyce , Patel Mulchand , Browne Richard , Rideout Todd 
Published: November 2023

During hypercholesterolemic pregnancies, the fetus is exposed to excessive cholesterol that is thought to increase cardiovascular disease risk in adults. We recently reported that newly‐weaned offspring from hypercholesterolemic apoE−/− mice have increased blood lipid concentrations that are normalized by maternal phytosterol (PS) supplementation throughout gestation and lactation. However, the influence of maternal hypercholesterolemia and PS supplementation on offspring oxysterols, bioactive oxygenated cholesterol derivatives that regulate arterial health and lesion progression, have yet to be addressed. Therefore, we tested the hypothesis that offspring born to hypercholesterolemic mothers would have increased circulating oxysterol concentrations and that pups from PS‐supplemented mothers would have a more favorable serum and hepatic oxysterol profile compared with pups from unsupplemented mothers. Twenty‐one female apoE−/− mice were randomly assigned to three different chow based diets throughout gestation and lactation: chow (chow; control), chow diet with high cholesterol (CH; 0.15% (w/w), and chow diet with 0.15% (w/w) cholesterol and 2% (w/w) phytosterol (CH/PS). On postnatal day 21, offspring were euthanized for serum and hepatic oxysterol profiling and transcriptional changes in hepatic sterol regulatory targets by HPLC and RT‐PCR, respectively. Pups born to hypercholesterolemic mothers had increased (p<0.05) serum cholesterol, 25‐hydroxycholesterol (HC), 7αHC, 7βHC, and 7‐ketocholesterol that were normalized by maternal PS‐supplementation. Hepatic mRNA expression of 7α‐hydroxylase (CYP7A1) was increased (p<0.05) in pups born to hypercholesterolemic mothers but normalized in pups from PS‐supplemented mothers. Compared with the CH group, pups from PS‐supplemented mothers demonstrated increased transcription of liver X receptor (LXR) and its target gene adenosine triphosphate binding cassette G8 (ABCG8). No difference (p>0.05) in the transcription of hepatic oxysterol binding proteins (OSBP 3, 8, and 7) was observed between the groups. These results suggest that, beyond increased circulating cholesterol, newly‐weaned offspring from hypercholesterolemic mothers have enhanced serum oxysterol concentrations and that maternal PS supplementation attenuates this response.Support or Funding InformationSupported by the National Institute for Complementary and Alternative Medicine.
Quantitation of Trans‐Fatty Acids in Human Plasma from the National Health and Nutrition Examination Survey
Authors: Kuiper Heather C , Caudill Samuel P , Vesper Hubert W 
Published: November 2023

Trans‐fatty acids (TFA) are geometric isomers of naturally occurring cis‐fatty acids, formed industrially via partial hydrogenation of vegetable oils or naturally in ruminant animals. High dietary TFA intake results in increased low density lipoprotein cholesterol levels and has been associated with other risk factors for cardiovascular disease. Due to these adverse health effects, reduction of TFA consumption is a major public health objective. Food intake studies have provided estimates for TFA levels in the U.S. population; however, there is a need for nationally representative data on TFA levels in blood.We developed and validated a new isotope dilution‐gaschromatography‐negative chemical ionization‐mass spectrometry (ID‐GC‐NCI‐MS)method for the quantitation of 27 FA including four major TFA in 100 μl of human plasma at levels as low as 0.02 μM. FA were derivatized with pentafluorobenzyl‐bromide and analyzed on a 7890/5975C GC/MSD from Agilent Technologies in selected ion monitoring mode using NCI with methane as there agent gas. Separation was carried out on an Agilent Select FAME 200m × 250μmx 0.25μm column with hydrogen as the carrier gas. The limits of detection were 0.07 μM for palmitelaidic acid, 0.28 μM for elaidic acid, 0.43 μM for trans‐vaccenic acid, and 0.02 μM for linoelaidic acid. The intraday and inter‐day percent coefficients of variation for the TFA ranged from 1–11%CV and 6–15%CV respectively. The mean accuracy for all four TFA was 102% (95%CI:98%–107%).We used this method to quantitate four major TFA, palmitelaidic acid, elaidic acid, trans‐vaccenic acid, and linoelaidic acid, in a nationally representative group of fasted adults in the U.S. population using National Health and Nutrition Examination Survey (NHANES) samples. The TFA were measured in 1613 participants from NHANES 1999–2000 and 2462 participants from NHANES2009–2010, and were detected in all samples. Geometric means for the sum of the 4 TFAs were 80.9 μmol/l (95% CI: 75.7,86.5 μmol/L) and 37.4 μmol/l (95% CI: 36.1, 38.8 μmol/L) in the NHANES 1999–2000 and 2009–2010, respectively. Overall TFA concentrations were 50% lower in NHANES 2009–2010 compared to 1999–2000.We developed a new highly specific, high resolution ID‐GC‐NCI‐MS method to quantitate TFA and regular FA in humans in large population studies. We used this method to determine TFA levels in fasted adults in the U.S. population from NHANES 1999–2000 and 2009–2010, finding an overall reduction of TFA levels.Support or Funding InformationNone
Almond fatty acid bioavailability in hyperlipidemia: A randomized controlled crossover trial
Authors: Nishi Stephanie K , Kendall Cyril WC , Bazinet Richard P , Jenkins David JA , Sievenpiper John L 
Published: November 2023

ObjectiveAlmond intake is associated with reduced coronary heart disease (CHD) risk, yet concern remains that weight gain may occur due to their high fat content and subsequent energy density. Our aim was to assess fatty acid bioavailability of almond intake, using linoleic acid (18:2n‐6) as a marker of fat absorption, in individuals with hyperlipidemia as part of a secondary analysis of a randomized controlled clinical trial.MethodsIn a randomized crossover study, 27 hyperlipidemic men and women incorporated 3 isoenergetic (mean 423 kcal/d) supplements into a NCEP Step 2 diet each for 1 month. Supplements provided 22.2% of energy and consisted of full‐dose almonds (73±3 g/d), half‐dose almonds plus half‐dose muffins, and full‐dose muffins (control), matched for linoleic acid content. Fecal samples were collected at the end of each treatment period. Fatty acids were measured in the dietary supplements and freeze‐dried fecal samples using gas chromatography.ResultsTwenty‐two participants had fecal fatty acid data available from all 3 dietary phases for analyses. In the control supplement, linoleic acid comprised of 5.4 mg/g (536 mg/d), comparable to the linoleic acid content of the almond supplement of 5.7 mg/g (428 mg/d). There was a significantly greater amount of fecal linoleic acid following almond intake (7201±1147 mg/d) compared with the control (1802±1102 mg/d), adjusted for linoleic intake (P<0.01). For every half dose increase in almond intake (i.e. approximately 37.5 g almonds/day) there was a 2693 mg/day increase in linoleic acid excreted in the feces (P‐trend = 0.0024).ConclusionsA dose‐response was observed with increasing linoleic acid excretion with increased almond intake. The fat content of almonds may not be as bioavailable as predicted by Atwater factors as suggested by the increased linoleic acid excretion with almond intake compared to the control. With less fat being bioavailable, meaning less kilocalories may be absorbed by the body, the concern of the ‘high energy density’ of almonds and risk of weight gain may be overstated.Protocol registration: clinicaltrials.gov identifier, [NCT00507520]Support or Funding InformationSource of Research Support: Almond Board of California; PSI Foundation; Banting and Best Diabetes Centre; Canadian Diabetes Association
The impact of soaring food prices on obesity in women: A longitudinal analysis in 31 developing countries
Authors: Conklin Annalijn I. , Daoud Adel , Shimkhada Riti , Ponce Ninez 
Published: November 2023

ObjectivesTo examine the association between food price inflation and obesity among women in low and middle‐income countries, and assess whether the association differs by socioeconomic status.MethodsLongitudinal study of the international prices of food (FAO food price index), which measures the monthly change in prices of a basket of food commodities, temporally and geographically linked to 295,984 non‐pregnant adult (age>=24 y) women participants in the Demographic and Health Survey (DHS) from 31 low‐ and middle‐income countries (2000–2014). Multilevel logistic regression with two‐level random‐intercept growth models was used to estimate the joint association of food price inflation and SES differences with obesity, conditioning on known confounders. Post‐estimation computed population averaged differences in the predicted probability of being obese across the range of food price inflation values.ResultsWe found that rising food prices were strongly associated with obesity prevalence, and particularly that the relationship showed clear differences by individual socioeconomic status (SES), regardless of the SES indicator used (Figs 1–5). The strongest disparities in the predicted mean obesity level were seen in education at the highest levels of food price inflation. On average, for every 1‐unit increase in food price inflation, women in the top SES categories had between 0.02 and 0.06 percentage point greater predicted obesity prevalence, compared to women in the bottom SES categories.ConclusionThere is robust effect modification by socioeconomic status of the association between food price inflation and obesity in adult women in developing countries. Greater food price inflation was associated with higher levels of obesity in women in the top SES groups, who may be net food consumers most at risk of obesity in developing countries.Support or Funding InformationThis work was supported by the Canadian Institute for Health Research Postdoctoral Fellowship Award (MFE‐135520). No sponsors participated in the study design, data analysis or interpretation of results.