bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Aldh1l2 Knockout on the Metabolic Profile of Mouse Liver
Authors: Sharma Jaspreet , Krupenko Natalia I. , Sumner Susan , Helke Kristi L. , Krupenko Sergey A.
Published: April 2020

ALDH1L2 (10‐formyltetrahydrofolate dehydrogenase), an enzyme involved in folate metabolism, resides in mitochondria where it converts 10‐formyl‐THF (tetrahydrofolate) to THF and CO2 in a NADP+‐dependent reaction. Though the enzyme could be an important contributor to the NADPH pool in mitochondria, its overall biological significance is not well understood. We have generated mice with a targeted Aldh1l2 knockout and demonstrated that the enzyme is involved in the regulation of lipid metabolism in the liver. Hepatic tissues from 12–14‐weeks‐old Aldh1l2+/+, Aldh1l2+/− and Aldh1l2−/− male mice were profiled to identify metabolite changes and to pinpoint associated pathways. Global metabolomic analysis was performed by Metabolon Inc. (Durham, NC) using Ultrahigh Performance Liquid Chromatography‐Tandem Mass Spectroscopy (UPLC‐MS/MS) for five samples from each group. Levels of 105 metabolites were decreased and levels of 162 metabolites were elevated in the Aldh1l2−/− compared to Aldh1l2+/+ mice. This analysis also found a Aldh1l2 gene‐dosage effect on the liver metabotype. Notably, no effect of the KO on levels of folate was seen. Metabolites that strongly contribute to the differentiation of the Aldh1l2+/+ and Aldh1l2−/− groups are involved in cysteine, glutathione, citric acid and fatty acid metabolism. Also, levels of intermediates in the CoA biosynthesis pathway, as well as levels of CoA itself, were significantly decreased in the livers of knockout mice. Together with the increased levels of several acylcarnitines seen in the KO mice, these findings indicate impaired mitochondrial beta‐oxidation of fatty acids. This conclusion is supported by histological analysis, which revealed accumulation of lipid vesicles in the livers of KO mice. Overall, our study shows that Aldh1l2 is a key regulator of lipid metabolism in the liver.

Support or Funding Information

These studies were supported by the National Institutes of Health grant DK054388 and CA095030( to S.A.K.)
Alternate fatty acid synthesis initiation in Escherichia coli
Authors: Whaley Sarah G. , Rock Charles O.
Published: April 2020

Fatty acid synthesis is important in both prokaryotes and eukaryotes for formation of functional membranes and dysregulation of the pathway has implications for cell growth and survival. In bacteria, fatty acid production is tightly regulated by the Type II fatty acid synthesis (FASII) pathway. FabH (3‐ketoacyl acyl carrier protein (ACP) synthase III) initiates fatty acid synthesis by condensing acetyl coenzyme A (acetyl‐CoA) with malonyl‐ACP in Escherichia coli. FabH was long thought to be the sole enzyme responsible for initiation of FASII and therefore essential for survival. The observation that fabH deletion strains are viable suggested the existence of an alternate initiation pathway. The yiiD gene was recently identified as essential for initiation of fatty acid synthesis in the absence of FabH in E. coli. The biochemical activity of YiiD is not known.

YiiD has an N‐terminal GCN5‐related N‐acetyltransferase (GNAT) domain and a C‐terminal hotdog domain that is annotated as a thioesterase. The full‐length protein, as well as the N‐terminal and C‐terminal domains were purified using an E. coli expression system. Full length YiiD and the C‐terminal hotdog domain are dimers and the N‐terminal GNAT domain is a monomer.

YiiD lacks condensing enzyme activity, suggesting that the initiation of FASII by YiiD is occurring through an alternate mechanism. We hypothesized that YiiD is initiating FASII by a transacylase reaction. FabH has acetyl‐CoA:ACP transacetylase activity, however protein extracts from an E. coli fabH deletion strain retain transacetylase activity. Purified YiiD has acetyl‐CoA:ACP transacetylase activity. The N‐terminal GNAT domain was inactive, whereas the C‐terminal domain was 100‐fold more active than intact YiiD. This suggests that the C‐terminal domain has the transacetylase active site and that the N‐terminal domain negatively regulates this activity. These data are consistent with YiiD forming acetyl‐ACP that is used by the elongation condensing enzymes (FabB or FabF) to initiate FASII thus bypassing FabH.

Support or Funding Information

National Institutes of Health Grant GM034496, Cancer Center (CORE) Support Grant CA21765, American and Lebanese Syrian Associated Charities (ALSAC)

Proposed model for alternate initiation of fatty acid synthesis by YiiD in E. coli

Figure 1
Lending a Helping Hand; Educational Value of a Hand‐Drawn Video Tutorial on Embryonic Underpinnings of Gross Anatomy
Authors: Ryan Megan Victoria , Stratford Jennifer , Lee Lisa
Published: April 2020

This study investigates the educational value of incorporating a hand‐drawn embryology video tutorial in an integrated gross anatomy course within a medical curriculum. Due to complex spatial and temporal dimensionalities, embryology is a difficult subject for students to learn, especially in an integrated curriculum with limited contact hours. However, thoughtfully integrated embryology concepts can support students’ understanding of gross anatomy. Short video tutorials can be an effective ancillary learning resource that can ensure content mastery, especially when paired with other pedagogical tools such as drawing.

A 10‐minute video tutorial on embryology of the innervation patterns of the skeletal muscle system was created, using a screen capture of hand‐drawn visual aids (Figure
1). In an IRB exempt study (#19‐1749), the first‐year medical students enrolled in an integrated anatomy course were instructed to view the tutorial, then take a quiz on the subject prior to the embryology lecture on the topic. Two days after the lecture, during an active learning session, students completed another quiz on the topic, as well as a survey assessing the perceived usefulness of the video. Significance of the quiz results was assessed using sigma‐restricted parameterization, whereas Tukey Honest Significant Difference and Chi‐Square tests were used to analyze the survey data.

The first quiz average was 84% (n=180) and the second quiz score average, completed two days later, was significantly lower at 63.3% (n=166) (
p<0.0001; h2=0.22). Surprisingly, students performed significantly worse on easy (simple recall) versus more difficult (problem‐solving) questions on the second quiz (
p<0.000; h2=0.14). Survey analytics revealed that 89% (n=128) of the participants reported they would like to have more hand‐drawn video tutorials in the future to supplement their learning. 42% (n=60) of the students additionally commented that the real‐time drawing helped them follow along. 86% (n=123) of survey participants stated that learning embryology helped them identify innervation patterns in adult gross anatomy.

The study suggests a potential value of the ancillary, hand‐drawn video tutorial on an embryology topic to enhance gross anatomy understanding, at least in the short term. While the significant knowledge decline in the second quiz is alarming, a number of confounds should be considered in its interpretation, such as different level of difficulty in the two quizzes, the quiz taking environments and the time‐allowed, which should be better controlled in the future study.

Screenshots of parts of the hand‐drawn video tutorial that was created.

Figure 1

Screenshots of parts of the hand‐drawn video tutorial that was created.

Figure 2
A Pipeline for the Rapid Production and Dissemination of Mouse Intersectional Genetic Alleles for Functional, Molecular, and Anatomical Neural Circuit Mapping. (mouseintersectionalgenetics.org)
Authors: Perdigones Manuel Alejandro Sarrion , Chang Yuan , Venken Koen , Ray Russell S.
Published: April 2020

Here we describe an effort to build and distribute a community library, based on public input, of more than 100 mouse intersectional genetic alleles to facilitate developmental, anatomical, molecular, and functional characterizations of neural circuit organization in behavior and physiology. Even within narrowly defined cell types, significant diversity is found at multiple levels including genetic and molecular signatures, activity patterns, and synaptic connectivity. Current challenges now center on tools to identify, access, and study cell populations with increasing precision. Intersectional genetics offers exceptionally high resolution to consistently delineate distinct cell types in the embryo and adult mouse for functional, molecular and anatomical studies. Intersectional genetics utilizes a ubiquitously expressed conditional allele that is activated by Cre and Flp site specific recombinases. Upon activation, the intersectional genetic alleles may express any number of Genetically Encodable Effector Molecules (GEEMS), such as channelrhodopsins for neural activity perturbations or an L10‐GFP ribotrap fusion to affinity purify translating mRNAs. The intersectional allele is activated by overlapping expression of both Flp and Cre recombinases in the same cell. Traditionally, these recombinases have been deployed as gene knock‐in or transgenic alleles that are designed to express in a cell or gene specific fashion. The use of two selectors (Cre and Flp) to define a cellular population enables high specificity and modularity in combining any set of Cre, Flp, and intersectional alleles to fit an experiment. The number of Cre and Flp recombinase mouse lines are constantly growing, giving greater access to increasing numbers of cell types. Additionally, these recombinases are the focus of multiple efforts to deploy them in ways that select cells based on other unique properties such as neuronal activity and synaptic connectivity. To make this powerful genetic approach more accessible to as many research laboratories as possible, we are building a production pipeline to create a suite of resources for anyone to easily make their own intersectional mouse line, to produce over 100 targeted ES cell lines that can be developed into mouse lines, as well as 10–15 high demand mouse lines all for public distribution. Priority for the GEEMS to be intersectionally deployed will be based on a public input collected at mouseintersectionalgenetics.org. All plasmids, cell lines, and mouse lines developed under this effort will be distributed without restriction to non‐profit research organizations (Addgene and Mutant Mouse Resource and Research Center; MMRRC).

Support or Funding Information

R21OD025327

Figure 1
Them1 Binds to Free Fatty Acids and is Allosterically Regulated by Lysophosphatidylcholine to Control Fatty Acyl‐CoA Hydrolysis in Brown Adipose Tissue
Authors: Tillman Matthew C. , Li Yue , Khadka Manoj C. , Imai Norihiro , Adhiyaman Akshitha C. , Juneja Puneet C. , Hagen Susan J. , Cohen David E. , Ortlund Eric A.
Published: April 2020

Obesity is a global epidemic, greatly increasing in prevalence over the past 30 years. In mammals, brown adipose tissue (BAT) counteracts obesity through thermogenesis: the burning of fat to produce heat. Thioesterase superfamily member 1 (Them1) is a multi‐domain enzyme in brown adipose tissue that slows thermogenesis by converting acyl‐CoA into fatty acids. Additionally, Them1 contains a lipid‐binding StAR‐related lipid transfer (START) domain with an unknown function. We hypothesized that the lipid‐binding START domain controls thermogenesis by either regulating its localization and/or functioning as a lipid sensor to regulate the activity of the enzymatic domains. To test this, we stably transduced brown adipocytes with full‐length and truncated Them1 without the START domain and found the START domain was necessary for proper localization to the lipid droplet, but not necessary for suppression of thermogenesis. Next, we used mass spectrometry, X‐ray crystallography, and microscale thermophoresis to identify long‐chained fatty acids, products of Them1’s enzymatic reaction, and lysophosphatidylcholine (LPC), important signaling lipids implicated in many diseases, bind to the START domain. We tested the impact of these lipids on Them1 enzymatic activity and found that 18:1 LPC inhibited Them1 activity in a START domain dependent manner. We identified LPC as a novel ligand and allosteric regulator of Them1 activity through the START domain. LPC species are elevated in BAT during thermogenesis and enhance the energy expenditure of the tissue; therefore, we postulate that LPC enhances thermogenesis in BAT through binding to the Them1 START domain and inhibiting the enzymatic activity of Them1.

Schematic of lysophosphatidylcholine inhibition of Them1 in brown adipocytes

Figure 1
Using a “favorite figure” to help students learn challenging pharmacology topics
Authors: Brandl Katharina
Published: April 2020

Objective

In the last two decades medical and pharmacy schools have shifted away from traditional, teacher‐centered curricula using didactic lectures as primary teaching modalities. New curricula offer a variety of teaching modalities including more active learning opportunities, small group teaching and self‐directed learning.

Integrating pharmacology instruction into curricula with more active learning opportunities and self‐directed learning can be challenging. Pharmacology is both, a basic science and a clinical science and students are sometimes uncertain what exact drug information (individual compounds versus drug classes) to learn.

To help students learn pharmacology in a more self‐directed environment, laminated flashcards containing the most important information about drug classes and individual compounds used to treat a specific disease state were developed. Each card contains also a “favorite figure” in which the mechanism of action of all different drug classes for a specific disease state are shown. This provides a more easily memorized framework that allows students to fit each detailed puzzle piece into a bigger concept.

Methods

Ten Drug Cards were developed to date and include following drug classes: Antiarrhythmics, Diabetes medications, Antiplatelet and Anticoagulants, Asthma medications, Analgesics, Immunosuppressants, Diuretics, Dyslipidemia Drugs, Drugs used for several Cardiovascular Diseases and Drugs targeting the Autonomic Nervous System. Second Year Pharmacy Students (n=64) of the Skaggs School of Pharmacy and Pharmaceutical Sciences at the University of California, San Diego were provided with these cards. Students were surveyed whether the Drug Cards helped them learn Pharmacology. Students were also questioned how they used the card to learn Pharmacology.

Results

The survey response rate was 89% (n=57). Ninety‐one percent of the students agreed or strongly agreed that the cards helped them learn pharmacology. Students commented that they used the card as a “great review tool” and a “quick reference guide”. They valued the card as “being handy”, and a “great study aid on the go”. Students also noted that the card helped them to decide what drug information is most essential.

Conclusion

Providing the students with a framework to study challenging pharmacology topics might help students to grasp the material without loosing the forest for the leaves.

Antiarrhythmics Drug Card Front Page

Figure 1

Antiarrhythmics Drug Card Back Page

Figure 2
Soluble claudin to study embryonic development
Authors: Keller Julie Young , Taylor Abigail , Mizrachi Dario Young
Published: April 2020

The cause and effect relationship between environmental factors, including toxins (naturally occuring) and toxicants (man‐made environmental contaminants), and embryonic development is well‐established. The claudin family of tetra‐spaning transmembrane proteins is essential for tight junction formation and regulation of paracellular transport between epithelial cells. Claudins also play a role in apical‐basal cell polarity, cell adhesion and link the tight junction to the actin cytoskeleton to exert effects on cell shape. The function of claudins in paracellular transport has been extensively studied through loss‐of‐function and gain‐of‐function studies in cell lines and in animal models, however, their role in morphogenesis has been less appreciated. Here we present a protein‐engineering approach to obtain soluble claudin proteins that preserve their function and organization as if they were membrane bound. We demonstrate their ability to influence embryonic development by simply adding these proteins to the environmental milieu of the animal model zebrafish embryos. We discuss their effectiveness in vivo to understand development and be as efficient as other methods that include manipulation of genomic DNA or messenger RNAs.

A: Zebrafish embryo 30 hpf, 30 C. Somites from this fish are presented below. B: Zebrafish embryo 30 hpf grown at 20 C. This represents delayed development. C: Zebrafish embryo 30 hpf grown at 30 C. Non‐influential protein. D: Zebrafish embryo 30 hpf grown at 30 C. Somites from this fish is presented below. Embryo treated with soluble claudin protein that targets the skin of the fish. In both D and Somites D it is observable the delayed development.

Figure 1
MicroRNAs Contribute to Angiotensin II‐Mediated Regulation of Transmural Electrical Remodeling in the Heart
Authors: Lu Michael Kaiyuan , Gordon Chris , Zuckerman Joan , Brink Peter , Cohen Ira
Published: April 2020

Activation of the local renin angiotensin system (RAS) by Angiotensin II (Ang II) in the heart induces electrical remodeling, including inhibition of transient outward potassium current Ito, prolongation of the action potential, and increased contractility. Moreover, the long‐term, persistent action of Ang II causes cardiac hypertrophy and heart failure (anatomic remodeling). The transmural gradient of multiple ionic currents, including Ito, is involved in Ang II‐mediated electrical remodeling. Differential expression of miRNAs may play a critical role in the signaling cascade for Ang II‐induced electrical remodeling. To investigate this hypothesis, a detailed analysis of potential miRNAs involved in Ang II‐mediated modulation was undertaken using miRNA microarray analysis of endocardium and epicardium tissue from the left ventricle of a Sprague‐Dawley rat. The left ventricular tissue samples were treated with either Ang II (2mM) or Losartan (2mM) to further screen for differences in miRNA expression between EPI and ENDO. Although forty‐nine miRNAs were expressed in a significant gradient between EPI and ENDO, only miR‐385‐5p and miR‐301a‐3p were found to exhibit similar expression patterns as Ito when modulated by Ang II. Taken together, these data suggest that miR‐382‐5p and miR‐301a‐3p could contribute to Ang II‐mediated transmural electrical remodeling and may provide a potential target for the study of heart failure mechanisms and therapeutic application.

Expression of miR‐382‐5p and miR‐301a‐3p in EPI and ENDO.A. Left: miR‐382‐5p is upregulated in EPI compared to ENDO. Middle: miR‐382‐5p is upregulated in EPI compared to EPI with Ang II. Right: miR‐382‐5p is downregulated in ENDO compared to ENDO with Losartan.B. Left: miR‐301a‐3p is downregulated in EPI compared to ENDO. Middle: miR‐301a‐3p is downregulated in EPI compared to EPI with Ang II. Right: miR‐301a‐3p is upregulated in ENDO compared to ENDO with Losartan.

Figure 1

Schematic diagram of Ang II‐mediated anatomic and electrical remodeling in the heart. The transmural distribution of Ang II causes the transmural gradient of ionic currents including Ito, Ip, ICaL and ICaTL (electrical remodeling). Under long term imbalances between volume load and maximum contractile strength, the heart undergoes hypertrophy and heart failure (anatomic remodeling). We hypothesize that miR‐382‐5p and miR‐301a‐3p contribute to Ang‐II mediated remodeling of the heart.

Figure 2
mTOR Inhibitor rapamycin can reverses the combination antiretroviral therapy induced central nervous system disorder
Authors: Chennakesavan Karthick
Published: April 2020

Background

Accumulating evidences indicate that the combined antiretroviral therapy (cART) has dramatically increased the life expectancy of HIV infected individuals. However, existing HIV population on cART show several complications including liver or pancreas damage, cardiovascular diseases and central nervous system disorders. Unexpectedly the prevalence of HIV+ associated neurotoxicity is on the rise. Hence, the current study is undertaken to determining the potential therapeutic effects of rapamycin against anti‐retroviral therapy induced neuronal dysfunction.

Objective

This study is aimed at exploring the therapeutic potential of rapamycin on cART induced central nervous system disorder.

Methodology

Primary midbrain neuronal cells (PMNC) were treated with antiretroviral drugs like Ritonavir (protease inhibitor) and Abacavir (reverse transcriptase inhibitor) in the combined form.

Results

After 24 hours treatment, immunoblot analysis shows that there is upregulation of autophagy marker proteins LC3 II, P62 levels in cART treated primary midbrain neuronal cells compared to control cells. Similarly, cART treated cells shows upregulation of endoplasmic reticulum (ER) resident proteins expression with mitochondrial dysfunction. These results are suggesting that neuronal cells treated with cART have dysregulated autophagy, higher ER stress and mitochondrial dysfunction. The beneficial effects of rapamycin are well described; though, it is unknown whether rapamycin ameliorates the harmful effects of cART‐induced toxicity in neuronal cells. Hence, in this study, we intend to investigate the effects of rapamycin on PMNC treated with cART. Our results indicate that rapamycin treatment ameliorates the autophagy dysfunction as well as, it normalizes the mitochondrial function and reduces the ER stress.

Conclusion

This study shows that rapamycin have a good potential in reversing cART‐induced autophagy and mitochondrial dysfunction in primary midbrain neuronal cells.

Schematic representation of therapetic effects of rapamycin

Figure 1
Solution NMR Studies of CYP121 of Mycobacterium tuberculosis; Evidence that Ligand Binding is Bi‐modal
Authors: Estrada D. Fernando , Campomizzi Christopher , Ferguson Shaun , Scheffler Emelie-Jo , Jay Natalie , Lioi James , Kumar Amit
Published: April 2020

Mycobacterium tuberculosis (Mtb) is the causative pathogen in the development of tuberculosis (TB). The rise of multi‐drug resistant forms of TB, combined with the fact that one third of the world’s population are carriers of latent TB, underscores the need for the development of novel anti‐TB agents. A current drug target is the cytochrome P450 (CYP) 121 of Mtb; an essential enzyme that mediates an unusual phenol coupling reaction of the dipeptide di‐cyclotyrosine (cYY). Our current understanding of atomic level active site/inhibitor interactions in CYP121 stems primarily from co‐crystallization of drug fragments or cYY with the enzyme. However, these studies result in protein structures that reflect the same unchanging conformation, thus resulting in a gap in our understanding of dynamic active site/ligand interactions that would otherwise help inform specificity in the design of novel CYP121 inhibitors.

In this preliminary work, we’ve begun to address this gap by adapting CYP121 for analysis by solution NMR. The enzyme produces a well‐dispersed, resolvable 1H‐15N HSQC spectrum. We have acquired 2D spectra of the enzyme while bound to a variety of azoles representing a range of ligand sizes and chemistry. We report that, while ligands with a similar overall structure (econazole and miconazole) produce similar perturbations of the NMR spectra, other ligands with distinct overall structures (ketoconazole and fluconazole) produce chemical shift perturbations that are unexpectedly similar to each other, yet can be categorized separately from other ligand‐induced changes. These preliminary studies suggest that ligand binding in CYP121 is partially bi‐modal, indicative of a structure that retains a semi‐rigid backbone in solution. This work lays the foundation for understanding CYP121 dynamics that will be a critical component of future drug design of novel anti‐TB agents.

Support or Funding Information

Research supported by start‐up funds at SUNY Buffalo

A backbone amide resonance of CYP121 in response to azole binding

Figure 1
Is There a Role for Compression Socks in Basketball? Potential Impact on Performance.
Authors: KANTOURIS NIKOLAOS , STEWART CLAIRE
Published: April 2020

Purpose

The aim of this study was to examine the effects of wearing compression socks (CS) on perceived exertion, biochemical parameters and performance parameters in untrained females after a basketball‐simulating exercise.

Methods

Seven untrained females (age 24.9 ± 0.4 years, height 161.7 ± 4.3 cm and weight 56.2 ± 7.0 kg) completed a basketball‐simulating exercise protocol on two occasions, in a random, counter‐balanced order: wearing either CS or placebo socks (PL) during exercise and recovery. Participants were requested to perform up to 6 circuits within 28 s each. Simulated basketball exercise included jogging, running, sprints, jumps, shuffles, all performed on a basketball court. Capillary blood samples were collected pre‐exercise and 1, 3, 5, 7, 9, 15, and 20 min post‐exercise for lactate determination. Three counter‐movement jumps (CMJ) were performed pre‐, 20 min post‐ and 72 h postexercise. Rating of perceived exertion (RPE) was obtained pre‐ and immediately postexercise. Three capillary blood samples were obtained pre‐, 20 min post‐ and 72 h postexercise for the determination of creatine kinase (CK) concentration. Data were analyzed by two‐way ANOVA with repeated measures for CK and CMJ and by paired t tests for RPE, lactate, comfort and tight scales.

Results

No differences were found between CS and PL for CMJ (Figure
1, p = 0.11), CK (p = 0.31), peak postexercise lactate (p = 0.21), 20 min post‐exercise lactate (p = 0.88), RPE (p = 0.52) and comfort (p = 0.36). However, tight feeling of socks was higher in CS when compared with PL (Figure
2, p < 0.001).

Conclusion

Despite increased compression, CS did not exert a positive impact on RPE, lactate peak and clearance, performance or a muscle damage marker after a basketball‐simulating exercise protocol in untrained female individuals.

Support or Funding Information

The authors received no specific funding for this work.

Counter‐movement jump height in compression and control groups. Values are mean ± SD.

Figure 1

Perceptual scales of comfort and tight feeling of socks prior to exercise between compression and control groups. Values are mean ± SD.

Figure 2
Tibetans and Han Chinese residents at intermediate altitude respond differently to chronic and simulated altitude‐induced hypoxia
Authors: Gu Wanjun , Wuren Tana , Qin Ga , Yan Ma , Wei Guan , Wagner Harrieth , Ge Ri-Li , Wagner Peter , Simonson Tatum
Published: April 2020

It has previously been shown that Tibetans residents at high altitude (> 4000m), have higher resting ventilation, lower heart rate, and higher blood‐oxygen saturation compared to Han Chinese residents at the same altitude. However, the extent to which these findings are due to differences in acclimatization versus innate variation between populations is unclear.

Thirty‐seven healthy, non‐smoking subjects, all resident at intermediate altitude (2200m) were studied. The subjects were of Tibetan (NMale = 10; NFemale = 9) and Han Chinese (NMale = 8; NFemale = 10) ancestries between ages of twenty to twenty‐five. The study was carried out under ambient conditions at 2200m and during acutely simulated altitude at 4200m in a hypobaric chamber. For each subject at rest, oxygen consumption (VO2), heart rate (HR), ventilation (VE), hemoglobin concentration ([Hb]), blood oxygen saturation (SaO2), and arterial blood gases were measured at both altitudes.

Tibetans males, compared to Han Chinese, tend to have 1.2 g/dl lower [Hb] at 4200 m and 0.89 g/dl lower [Hb] at 2200 m. However, the difference is only significant at 2200 m (p = 0.036), and no difference in [Hb] is found in females.

At 2200 m, Tibetan males have significantly lower resting heart rate compared to Han Chinese males (p = 0.0062). At 4200 m, this difference persists: both Tibetan males and females have lower resting heart rates than their Han Chinese counterparts (p = 0.042, p = 0.043).

At both 2200 m and 4200 m, Tibetan females tend to have significantly higher VO2 (both p = 0.043), higher VCO2 (p = 0.027, p = 0.033) and higher VE (p = 0.018, p = 0.019) compared to Han Chinese females, suggesting increased ventilation. In males, no differences in VO2 or VCO2 were observed at 2200 m and 4200 m, and Tibetan males tend to have higher VE only at 4200 m, though the result is not statistically significant (p = 0.12).

At 2200 m, there is no difference of SaO2 between Tibetans and Han Chinese; all groups have SaO2 well above ninety percent. However, the difference of SaO2 is more pronounced at 4200 m. Both Tibetan males and females have higher SaO2 compared to Han Chinese, although the result is only significant in the males (p = 0.045) and exhibits a trend in females (p = 0.15).

In conclusion, Tibetans, whose ancestors lived at ~4200m, retain certain physiological traits when resident at 2200m. These include lower resting [Hb], higher VO2, VCO2 and VE. When acutely exposed to altitude‐induced hypoxia, Tibetans tend to maintain higher resting SaO2 and VO2. Therefore, the differences we found between Tibetans and Han Chinese are likely due more to innate differences, such as genetic and epigenetic programs.

Table 1
The early scientific connections of Richard Price
Authors: Diniz Marcio A. , Bellhouse David R.
Published: April 2020

The minutes of the scientific meetings of the Royal Society reveal 23 meetings attended by Richard Price between 1751 and 1764, when he was not yet a Fellow. Examining the names of the Fellows present and the subjects discussed in those meetings we were able to unfold a network of connections Price established at a very young age. Given the scarcity of details about Price's early career, our article sheds some light on this period in the life of a Fellow of the Royal Society with key contributions in several fields.
Zinc-α2-glycoprotein as an inhibitor of amine oxidase copper-containing 3
Authors: Romauch Matthias
Published: April 2020

Zinc-α2-glycoprotein (ZAG) is a major plasma protein whose levels increase in chronic energy-demanding diseases and thus serves as an important clinical biomarker in the diagnosis and prognosis of the development of cachexia. Current knowledge suggests that ZAG mediates progressive weight loss through β-adrenergic signalling in adipocytes, resulting in the activation of lipolysis and fat mobilization. Here, through cross-linking experiments, amine oxidase copper-containing 3 (AOC3) is identified as a novel ZAG binding partner. AOC3—also known as vascular adhesion protein 1 (VAP-1) and semicarbazide sensitive amine oxidase (SSAO)—deaminates primary amines, thereby generating the corresponding aldehyde, H
2
O
2
and NH
3
. It is an ectoenzyme largely expressed by adipocytes and induced in endothelial cells during inflammation. Extravasation of immune cells depends on amine oxidase activity and AOC3-derived H
2
O
2
has an insulinogenic effect. The observations described here suggest that ZAG acts as an allosteric inhibitor of AOC3 and interferes with the associated pro-inflammatory and anti-lipolytic functions. Thus, inhibition of the deamination of lipolytic hormone octopamine by AOC3 represents a novel mechanism by which ZAG might stimulate lipolysis. Furthermore, experiments involving overexpression of recombinant ZAG reveal that its glycosylation is co-regulated by oxygen availability and that the pattern of glycosylation affects its inhibitory potential. The newly identified protein interaction between AOC3 and ZAG highlights a previously unknown functional relationship, which may be relevant to inflammation, energy metabolism and the development of cachexia.
Vibrations of nonlinear elastic lattices: low- and high-frequency dynamic models, internal resonances and modes coupling
Authors: Andrianov Igor V. , Danishevskyy Vladyslav V. , Rogerson Graham
Published: April 2020

We aim to study how the interplay between the effects of nonlinearity and heterogeneity can influence on the distribution and localization of energy in discrete lattice-type structures. As the classical example, vibrations of a cubically nonlinear elastic lattice are considered. In contrast with many other authors, who dealt with infinite and periodic lattices, we examine a finite-size model. Supposing the length of the lattice to be much larger than the distance between the particles, continuous macroscopic equations suitable to describe both low- and high-frequency motions are derived. Acoustic and optical vibrations are studied asymptotically by the method of multiple time scales. For numerical simulations, the Runge–Kutta fourth-order method is employed. Internal resonances and energy exchange between the vibrating modes are predicted and analysed. It is shown that the decrease in the number of particles restricts energy transfers to higher-order modes and prevents the equipartition of energy between all degrees of freedom. The conditions for a possible reduction in the original nonlinear system are also discussed.
Wave scattering on lattice structures involving an array of cracks
Authors: Maurya Gaurav , Lal Sharma Basant
Published: April 2020

Scattering of waves as a result of a vertical array of equally spaced cracks on a square lattice is studied. The convenience of Floquet periodicity reduces the study to that of scattering of a specific wave-mode from a single crack in a waveguide. The discrete Green’s function, for the waveguide, is used to obtain the semi-analytical solution for the scattering problem in the case of finite cracks whereas the limiting case of semi-infinite cracks is tackled by an application of the Wiener–Hopf technique. Reflectance and transmittance of such an array of cracks, in terms of incident wave parameters, is analysed. Potential applications include construction of tunable atomic-scale interfaces to control energy transmission at different frequencies.
Greater variability in chimpanzee (
Pan troglodytes
) brain structure among males
Authors: DeCasien Alex R. , Sherwood Chet C. , Schapiro Steven J. , Higham James P.
Published: April 2020

Across the animal kingdom, males tend to exhibit more behavioural and morphological variability than females, consistent with the ‘greater male variability hypothesis'. This may reflect multiple mechanisms operating at different levels, including selective mechanisms that produce and maintain variation, extended male development, and X chromosome effects. Interestingly, human neuroanatomy shows greater male variability, but this pattern has not been demonstrated in any other species. To address this issue, we investigated sex-specific neuroanatomical variability in chimpanzees by examining relative and absolute surface areas of 23 cortical sulci across 226 individuals (135F/91M), using permutation tests of the male-to-female variance ratio of residuals from MCMC generalized linear mixed models controlling for relatedness. We used these models to estimate sulcal size heritability, simulations to assess the significance of heritability, and Pearson correlations to examine inter-sulcal correlations. Our results show that: (i) male brain structure is relatively more variable; (ii) sulcal surface areas are heritable and therefore potentially subject to selection; (iii) males exhibit lower heritability values, possibly reflecting longer development; and (iv) males exhibit stronger inter-sulcal correlations, providing indirect support for sex chromosome effects. These results provide evidence that greater male neuroanatomical variability extends beyond humans, and suggest both evolutionary and developmental explanations for this phenomenon.
Differential ventilation using flow control valves as a potential bridge to full ventilatory support during the COVID-19 crisis: From bench to bedside
Authors: Levin Matthew A. , Chen Martin D. , Shah Anjan , Shah Ronak , Zhou George , Kane Erica , Burnett Garrett , Ranginwala Shams , Madek Jonathan , Gidicsin Christopher , Park Chang , Katz Daniel , Salter Benjamin , Kohli-Seth Roopa , Lin Hung-Mo , Eisenkraft James B. , Uysal Suzan , McCarry Michael , Reich David L. , Leibowitz Andrew B.
Published: April 2020

Background

It has been projected that there will be too few ventilators to meet demand during the COVID-19 (SARS CoV-2) pandemic. Ventilator sharing has been suggested as a crisis standard of care strategy to increase availability of mechanical ventilation. The safety and practicality of shared ventilation in patients is unknown. We designed and evaluated a system whereby one mechanical ventilator can be used to simultaneously ventilate two patients who have different lung compliances using a custom manufactured flow control valve to allow for individual adjustment of tidal volume and airway pressure for each patient.

Methods

The system was first evaluated in a simulation lab using two human patient simulators under expected clinical conditions. It was then tested in an observational study of four patients with acute respiratory failure due to COVID-19. Two separately ventilated COVID-19 patients were connected to a single ventilator for one hour. This intervention was repeated in a second pair of patients. Ventilatory parameters (tidal volume, peak airway pressures, compliance) were recorded at five minute intervals during both studys. Arterial blood gases were taken at zero, thirty, and sixty minutes. The primary outcome was maintenance of stable acid-base status and oxygenation during shared ventilation.

Results

Two male and two female patients, age range 32-56 yrs, participated. Ideal body weight and driving pressure were markedly different among patients. All patients demonstrated stable physiology and ventilation for the duration of shared ventilation. In one patient tidal volume was increased after 30 minutes to correct a respiratory acidosis.

Conclusions

Differential ventilation using a single ventilator and a split breathing circuit with flow control valves is possible. A single ventilator could feasibly be used to safely ventilate two COVID-19 patients simultaneously as a bridge to full ventilatory support.

Summary Statement

Not applicable.
Outcomes of hydroxychloroquine usage in United States veterans hospitalized with Covid-19
Authors: Magagnoli Joseph , Narendran Siddharth , Pereira Felipe , Cummings Tammy , Hardin James W. , Sutton S. Scott , Ambati Jayakrishna
Published: April 2020

BACKGROUND

Despite limited and conflicting data on the use of hydroxychloroquine in patients with Covid-19, the U.S. Food and Drug Administration has authorized the emergency use of this drug when clinical trials are unavailable or infeasible. Hydroxychloroquine, alone or in combination with azithromycin, is being widely used in Covid-19 therapy based on anecdotal and limited observational evidence.

METHODS

We performed a retrospective analysis of data from patients hospitalized with confirmed SARS-CoV-2 infection in all United States Veterans Health Administration medical centers until April 11, 2020. Patients were categorized based on their exposure to hydroxychloroquine alone (HC) or with azithromycin (HC+AZ) as treatments in addition to standard supportive management for Covid-19. The two primary outcomes were death and the need for mechanical ventilation. We determined the association between treatment and the primary outcomes using competing risk hazard regression adjusting for clinical characteristics via propensity scores. Discharge and death were taken into account as competing risks and subdistribution hazard ratios are presented.

RESULTS

A total of 368 patients were evaluated (HC, n=97; HC+AZ, n=113; no HC, n=158). Rates of death in the HC, HC+AZ, and no HC groups were 27.8%, 22.1%, 11.4%, respectively. Rates of ventilation in the HC, HC+AZ, and no HC groups were 13.3%, 6.9%, 14.1%, respectively. Compared to the no HC group, the risk of death from any cause was higher in the HC group (adjusted hazard ratio, 2.61; 95% CI, 1.10 to 6.17; P=0.03) but not in the HC+AZ group (adjusted hazard ratio, 1.14; 95% CI, 0.56 to 2.32; P=0.72). The risk of ventilation was similar in the HC group (adjusted hazard ratio, 1.43; 95% CI, 0.53 to 3.79; P=0.48) and in the HC+AZ group (adjusted hazard ratio, 0.43; 95% CI, 0.16 to 1.12; P=0.09), compared to the no HC group.

CONCLUSIONS

In this study, we found no evidence that use of hydroxychloroquine, either with or without azithromycin, reduced the risk of mechanical ventilation in patients hospitalized with Covid-19. An association of increased overall mortality was identified in patients treated with hydroxychloroquine alone. These findings highlight the importance of awaiting the results of ongoing prospective, randomized, controlled studies before widespread adoption of these drugs.
Two patients with acute meningo-encephalitis concomitant to SARS-CoV-2 infection
Authors: Bernard-Valnet Raphaël , Pizzarotti Beatrice , Anichini Angelica , Demars Yoris , Russo Enrico , Schmidhauser Marie , Cerutti-Sola Jonathan , Rossetti Andrea O. , Pasquier Renaud Du
Published: April 2020

Human coronaviruses are known for their tropism for central nervous system and to be associated with neurological complications. SARS-CoV-2 pandemy represent a major health issue and if respiratory symptoms are at the forefront, neurological symptoms should be expected. Here we report the case of two patient that developed encephalitic symptoms with neuropsychological impairment and pathologic cerebrospinal fluid features concomitantly to SARS-CoV-2 documented infection. Both patient recovered promptly without treatment. This report raises the question of central nervous system involvement in SARS-CoV-2 infection and the need for investigation of neuropsychological complications in infected patient.
Leveraging Deep Learning to Simulate Coronavirus Spike proteins has the potential to predict future Zoonotic sequences
Authors: Crossman Lisa C
Published: April 2020

Motivation

Coronaviridae are a family of positive-sense RNA viruses capable of infecting humans and animals. These viruses usually cause a mild to moderate upper respiratory tract infection, however, they can also cause more severe symptoms, gastrointestinal and central nervous system diseases. These viruses are capable of flexibly adapting to new environments, hence health threats from coronavirus are constant and long-term. Immunogenic spike proteins are glyco-proteins found on the surface of Coronaviridae particles that mediate entry to host cells. The aim of this study was to train deep learning neural networks to produce simulated spike protein sequences, which may be able to aid in knowledge and/or vaccine design by creating alternative possible spike sequences that could arise from zoonotic sources in future.

Results

Here we have trained deep learning recurrent neural networks (RNN) to provide computer-simulated coronavirus spike protein sequences in the style of previously known sequences and examine their characteristics. Training used a dataset of alpha, beta, gamma and delta coronavirus spike sequences. In a test set of 100 simulated sequences, all 100 had most significant BLAST matches to Spike proteins in searches against NCBI non-redundant dataset (NR) and also possessed concomitant Pfam domain matches.

Conclusions

Simulated sequences from the neural network may be able to guide us in future with prospective targets for vaccine discovery in advance of a potential novel zoonosis. We may effectively be able to fast-forward through evolution using neural networks to investigate sequences that could arise.
Affinity proteomic dissection of the human nuclear cap-binding complex interactome
Authors: Dou Yuhui , Kalmykova Svetlana , Pashkova Maria , Oghbaie Mehrnoosh , Jiang Hua , Molloy Kelly R. , Chait Brian T. , Rout Michael P. , Fenyö David , Jensen Torben Heick , Altukhov Ilya , LaCava John
Published: April 2020

A 5’, 7-methylguanosine cap is a quintessential feature of RNA polymerase II-transcribed RNAs, and a textbook aspect of co-transcriptional RNA processing. The cap is bound by the cap-binding complex (CBC), canonically consisting of nuclear cap-binding proteins 1 and 2 (NCBP1/2). The CBC has come under renewed investigative interest in recent years due to its participation in RNA-fate decisions via interactions with RNA productive factors as well as with adapters of the degradative RNA exosome - including the proteins SRRT (a.k.a. ARS2) and ZC3H18, and macromolecular assemblies such as the nuclear exosome targeting (NEXT) complex and the poly(A) exosome targeting (PAXT) connection. A novel cap-binding protein, NCBP3, was recently proposed to form an alternative, non-canonical CBC together with NCBP1, and to interact with the canonical CBC along with the protein SRRT. The theme of post-transcriptional RNA fate, and how it relates to co-transcriptional ribonucleoprotein assembly is abundant with complicated, ambiguous, and likely incomplete models. In an effort to clarify the compositions of NCBP1-, 2-, and 3-related macromolecular assemblies, including their intersections and differences, we have applied an affinity capture-based interactome screening approach, where the experimental design and data processing have been modified and updated to identify interactome differences between targets under a range of experimental conditions, in the context of label-free quantitative mass spectrometry. This study generated a comprehensive view of NCBP-protein interactions in the ribonucleoprotein context and demonstrates the potential of our approach to benefit the interpretation of complex biological pathways.
Sequence determinants and evolution of constitutive and alternative splicing in yeast species
Authors: Schirman Dvir , Yakhini Zohar , Dahan Orna , Pilpel Yitzhak
Published: April 2020

RNA splicing is a key process in eukaryotic gene expression. Most Intron-containing genes are constitutively spliced, hence efficient splicing of an intron is crucial for efficient gene expression. Here we use a large synthetic oligo library of ~20,000 variants to explore how different intronic sequence features affect splicing efficiency and mRNA expression levels inS. cerevisiae. Using a combinatorial design of synthetic introns we demonstrate how non-consensus splice site sequences affect splicing efficiency in each of the three splice sites. We then show thatS. cerevisiaesplicing machinery tends to select alternative 3’ splice sites downstream of the original site, and we suggest that this tendency created a selective pressure, leading to the avoidance of cryptic splice site motifs near introns’ 3’ ends. We further use natural intronic sequences from other yeast species, whose splicing machineries have diverged to various extents, to show how intron architectures in the various species have been adapted to the organism’s splicing machinery. We suggest that the observed tendency for cryptic splicing is a result of a loss of a specific splicing factor, U2AF1. Lastly, we show that synthetic sequences containing two introns give rise to alternative RNA isoforms inS. cerevisiae, exposing intronic features that control and facilitate alternative splicing. Our study reveals novel mechanisms by which introns are shaped in evolution to allow cells to regulate their transcriptome.