Nectar feeding beyond the tongue: hummingbirds drink using phase-shifted bill opening, flexible tongue flaps and wringing at the tips

Hummingbirds are the most speciose group of vertebrate nectarivores and exhibit striking bill variation in association with their floral food sources. To explicitly link comparative feeding biomechanics to hummingbird ecology, deciphering how they move nectar from the tongue to the throat is as important as understanding how this liquid is collected. We employed synced, orthogonally positioned, high-speed cameras to describe the bill movements, and backlight filming to track tongue and nectar displacements intraorally. We reveal that the tongue base plays a central role in fluid handling, and that the bill is neither just a passive vehicle taking the tongue inside the flower nor a static tube for the nectar to flow into the throat. Instead, we show that the bill is actually a dynamic device with an unexpected pattern of opening and closing of its tip and base. We describe three complementary mechanisms: (1) distal wringing: the tongue is wrung out as soon as it is retracted and upon protrusion, near the bill tip where the intraoral capacity is decreased when the bill tips are closed; (2) tongue raking: the nectar filling the intraoral cavity is moved mouthwards by the tongue base, leveraging flexible flaps, upon retraction; (3) basal expansion: as more nectar is released into the oral cavity, the bill base is open (phase-shifted from the tip opening), increasing the intraoral capacity to facilitate nectar flow towards the throat.

Association of Elevated Arterial Stiffness With Cardiac Target Organ Damage and Cardiac Autonomic Neuropathy in Young Adults With Diabetes: The SEARCH for Diabetes in Youth Study

OBJECTIVE

Adults with diabetes are at risk for cardiovascular (CV) events, possibly due to increased arterial stiffness (AS) and cardiac autonomic neuropathy (CAN). We sought to determine whether 1) AS is associated with cardiac target organ damage in young adults with youth-onset diabetes, 2) whether CAN is associated with AS, as one possible etiology for increased AS in this cohort, and 3) whether these relationships differ by type of diabetes.

RESEARCH DESIGN AND METHODS

Participants from the SEARCH for Diabetes in Youth Study (type 1 diabetes [T1D], n = 222; type 2 diabetes [T2D], n = 177; mean age 23 years) had clinical, echocardiographic, AS, and CAN assessed. Linear regression was performed to determine whether AS was associated with cardiac changes and CAN and whether relationships differed by diabetes type.

RESULTS

AS was significantly associated with cardiac structure (left ventricular mass index, P < 0.0001), systolic function (ejection fraction, P = 0.03) and diastolic function (transmitral peak early [E]/atrial [A] wave velocities ratio, P = 0.008; early [e']/atrial [a'] waves, P = 0.02) after adjustments for CV risk factors. The association between AS and CAN was not significant when other important covariates were added. These relationships were mostly similar in both T1D and T2D.

CONCLUSIONS

AS is associated with cardiac changes in young adults with diabetes. CAN-induced AS does not appear to be an etiology for cardiac abnormalities in this cohort.

Zebrafish cutaneous injury models reveal that Langerhans cells engulf axonal debris in adult epidermis

Somatosensory neurons extend enormous peripheral axons to the skin, where they detect diverse environmental stimuli. Somatosensory peripheral axons are easily damaged due to their small caliber and superficial location. Axonal damage results in Wallerian degeneration, creating vast quantities of cellular debris that phagocytes must remove to maintain organ homeostasis. The cellular mechanisms that ensure efficient clearance of axon debris from stratified adult skin are unknown. Here, we established zebrafish scales as a tractable model to study axon degeneration in the adult epidermis. Using this system, we demonstrated that skin-resident immune cells known as Langerhans cells engulf the majority of axon debris. In contrast to immature skin, adult keratinocytes did not significantly contribute to debris removal, even in animals lacking Langerhans cells. Our study establishes a powerful new model for studying Wallerian degeneration and identifies a new function for Langerhans cells in maintenance of adult skin homeostasis following injury. These findings have important implications for pathologies that trigger somatosensory axon degeneration.

National work-family policies and the occupational segregation of women and mothers in European countries, 1999-2016

Some scholars hypothesize that although work-family policies help incorporate women into the labour market, they do so by integrating women, and mothers specifically, into female-dominated occupations. Some suggest that although these policies are 'good' for lower educated women, they harm higher educated women by concentrating them in female-dominated professions. We revisit this debate using the highest quality data brought to bear on this question to date. We use the EU Labour Force Survey 1999-2016 (n = 21 countries, 235 country-years, 2.5 million men and women aged 20-44), combined with an original collection of country-year indicators. Specifically, we examine how the two most widely studied work-family policies-paid parental leave and early childhood education and care (ECEC)-and public sector size affect occupational segregation for men and women by educational attainment and parental status. We find no evidence that 'generous' welfare states promote segregation. Rather, a specific policy-parental leave in excess of 9 months-promotes segregation between men and women broadly, but most acutely for non-tertiary-educated mothers. Findings are generally null for paid leave of up to 9 months. ECEC is associated with greater integration, particularly for tertiary-educated women. Large public sectors are associated with segregation, with both tertiary-educated men and women more likely to work in feminized occupations. Public sector size, however, is not as tightly bundled with work-family policies as previous work suggests.

Design and Characterization of a Novel Venetoclax-Zanubrutinib Nano-Combination for Enhancing Leukemic Cell Uptake and Long-Acting Plasma Exposure

Leukemia remains incurable partly due to difficulties in reaching and maintaining therapeutic drug concentrations in the target tissues and cells. Next-generation drugs targeted to multiple cell checkpoints, including the orally active venetoclax (Bcl-2 target) and zanubrutinib (BTK target), are effective and have improved safety and tolerability compared to conventional, nontargeted chemotherapies. However, dosing with a single agent frequently leads to drug resistance; asynchronous coverage due to the peak-and-trough time-course of two or more oral drugs has prevented drug combinations from simultaneously knocking out the respective drugs' targets for sustained leukemia suppression. Higher doses of the drugs may potentially overcome asynchronous drug exposure in leukemic cells by saturating target occupancy, but higher doses often cause dose-limiting toxicities. To synchronize multiple drug target knockout, we have developed and characterized a drug combination nanoparticle (DcNP), which enables the transformation of two short-acting, orally active leukemic drugs, venetoclax and zanubrutinib, into long-acting nanoformulations (VZ-DCNPs). VZ-DCNPs exhibit synchronized and enhanced cell uptake and plasma exposure of both venetoclax and zanubrutinib. Both drugs are stabilized by lipid excipients to produce the VZ-DcNP nanoparticulate (d ~ 40 nm) product in suspension. The VZ-DcNP formulation has enhanced uptake of the two drugs (VZ) in immortalized leukemic cells (HL-60), threefold over that of its free drug counterpart. Additionally, drug-target selectivity of VZ was noted with MOLT-4 and K562 cells that overexpress each target. When given subcutaneously to mice, the half-lives of venetoclax and zanubrutinib were extended by approximately 43- and 5-fold, respectively, compared to an equivalent free VZ. Collectively, these data suggest that VZ in VZ-DcNP warrant consideration for preclinical and clinical development as a synchronized and long-acting drug-combination for the treatment of leukemia.

Biomimetic Dentin Repair: Amelogenin-Derived Peptide Guides Occlusion and Peritubular Mineralization of Human Teeth

Exposure of dentin tubules due to loss of protective enamel (crown) and cementum (root) tissues as a result of erosion, mechanical wear, gingival recession, etc. has been the leading causes of dentin hypersensitivity. Despite being a widespread ailment, no permanent solution exists to address this oral condition. Current treatments are designed to alleviate the pain by either using desensitizers or blocking dentin tubules by deposition of minerals or solid precipitates, which often have short-lived effects. Reproducing an integrated mineral layer that occludes exposed dentin with concomitant peritubular mineralization is essential to reestablish the structural and mechanical integrity of the tooth with long-term durability. Here, we describe a biomimetic treatment that promotes dentin repair using a mineralization-directing peptide, sADP5, derived from amelogenin. The occlusion was achieved through a layer-by-layer peptide-guided remineralization process that forms an infiltrating mineral layer on dentin. The structure, composition, and nanomechanical properties of the remineralized dentin were analyzed by cross-sectional scanning electron microscopy imaging, energy dispersive X-ray spectroscopy, and nanomechanical testing. The elemental analysis provided calcium and phosphate compositions that are similar to those in hydroxyapatite. The measured average hardness and reduced elastic modulus values for the mineral layer were significantly higher than those of the demineralized and sound human dentin. The structural integration of the new mineral and underlying dentin was confirmed by thermal aging demonstrating no physical separation. These results suggest that a structurally robust and mechanically durable interface is formed between the interpenetrating mineral layer and underlying dentin that can withstand long-term mechanical and thermal stresses naturally experienced in the oral environment. The peptide-guided remineralization procedure described herein could provide a foundation for the development of highly effective oral care products leading to novel biomimetic treatments for a wide range of demineralization-related ailments and, in particular, offers a potent long-term solution for dentin hypersensitivity.

Characterizing variability of electronic health record-driven phenotype definitions

OBJECTIVE

The aim of this study was to analyze a publicly available sample of rule-based phenotype definitions to characterize and evaluate the variability of logical constructs used.

MATERIALS AND METHODS

A sample of 33 preexisting phenotype definitions used in research that are represented using Fast Healthcare Interoperability Resources and Clinical Quality Language (CQL) was analyzed using automated analysis of the computable representation of the CQL libraries.

RESULTS

Most of the phenotype definitions include narrative descriptions and flowcharts, while few provide pseudocode or executable artifacts. Most use 4 or fewer medical terminologies. The number of codes used ranges from 5 to 6865, and value sets from 1 to 19. We found that the most common expressions used were literal, data, and logical expressions. Aggregate and arithmetic expressions are the least common. Expression depth ranges from 4 to 27.

DISCUSSION

Despite the range of conditions, we found that all of the phenotype definitions consisted of logical criteria, representing both clinical and operational logic, and tabular data, consisting of codes from standard terminologies and keywords for natural language processing. The total number and variety of expressions are low, which may be to simplify implementation, or authors may limit complexity due to data availability constraints.

CONCLUSIONS

The phenotype definitions analyzed show significant variation in specific logical, arithmetic, and other operators but are all composed of the same high-level components, namely tabular data and logical expressions. A standard representation for phenotype definitions should support these formats and be modular to support localization and shared logic.

Geometry-dependent valence tautomerism, magnetism, and electrical conductivity in 1D iron–tetraoxolene chains

Here we show how a simple change in the geometry of 1D iron–tetraoxolene chains dramatically alters the observed physical properties, including the presence of valence tautomerism, strong magnetic coupling, and electrical conductivity.

Bird conservation status and cultural values in Indigenous Mexican communities: towards a bioculturally informed conservation policy

BACKGROUND

We summarize comparative ethnoornithological data for ten Mexican Indigenous communities, an initial step towards a comprehensive archive of the avian diversity conserved within Mexico's Indigenous territories. We do so by counting highlighted species listed for bird conservation status on widely recognized "red lists" and their cultural value to build biocultural policies in Mexico for their conservation.

METHODS

Indigenous bird names for each study site were determined to allow calculation of the "Scientific Species Recognition Ratio" (SSRR) for high cultural value birds obtained across communities. This demonstrated patterns of cultural prominence. A matrix of 1275 bird versus seven biocultural values was analysed using a correspondence analysis (InfoStat/L-v2020) to illustrate patterns of concordance between bird conservation status and cultural values.

RESULTS

This paper contributes to quantitative and qualitative data on the role of ethnoornithology and ethnobiology in biocultural conservation. The areas studied provide refugia for almost 70% of the Mexican avifauna within a fraction of 1% of the national territory, that is 769 bird species recorded for all communities. The global correspondence of regions of biological and linguistic megadiversity is well established, while linguistic diversity is widely accepted as a good proxy for general cultural diversity. Our correspondence analysis explained 81.55% of the variation, indicating a strong relation between cultural importance and bird conservation status. We propose three main categories to establish a bioculturally informed public policy in Mexico for the conservation of what we described as high, medium, and bioculturally prominent bird species all include cultural value in any material or symbolic aspect. High are those species appearing on any threatened list, but also considered in any endemic status, while medium include threatened listed species. The last category included species not necessarily listed on any threat list, but with a wide range of social and cultural uses. We suggest that the concept might be extended to other species of biocultural importance.

CONCLUSIONS

We argue that bird conservation policies should be biocultural, that is they should recognize birds of cultural value on a par with bird species "of special interest" because they are most critical for biodiversity conservation. The desire of local people to protect their traditional community lands and livelihoods can be an effective biodiversity conservation strategy, which should be recognized in national biocultural policies.

Polygenic risk score for ACE-inhibitor-associated cough based on the discovery of new genetic loci

AIMS

To search for sequence variants associated with ACEi discontinuation and to test their association with ACEi-associated adverse drug reactions (ADRs).

METHODS AND RESULTS

A genome-wide association study (GWAS) on ACEi discontinuation was conducted, including 33 959 ACEi-discontinuers and 44 041 controls. Cases were defined as persons who switched from an ACEi treatment to an angiotensin receptor blocker. Controls were defined as persons who continued ACEi treatment for at least 1 year. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed for ACEi discontinuation risk by mixed model regression analysis. Summary statistics from the individual cohorts were meta-analyzed with a fixed-effects model. To test for association with specific ACEi-associated ADRs, any genome-wide significant (P < 5 × 10-8) ACEi discontinuation variants was tested for association with ACEi-associated cough and angioedema. A polygenetic risk score (PRS) based on ACEi discontinuation GWAS data was constructed and tested for association with ACEi-associated cough and angioedema in two population-based samples. In total, seven genetic genome-wide loci were identified, of which six were previously unreported. The strongest association with ACEi discontinuation was at 20q13.3 (NTSR1; OR: 1.21; 95% CI: 1.17-1.24; P = 2.1 × 10-34). Five of seven lead variants were associated with ACEi-associated cough, whereas none were associated with ACEi-associated angioedema. The ACEi discontinuation PRS was associated with ACEi-associated cough in a dose-response manner but not with ACEi-associated angioedema. ACEi discontinuation was genetically correlated with important causes for cough, including gastro-esophageal reflux disease, allergic rhinitis, hay fever, and asthma, which indicates partly shared genetic underpinning between these traits.

CONCLUSION

This study showed the advantage of using prescription patterns to discover genetic links with ADRs. In total, seven genetic loci that associated with ACEi discontinuation were identified. There was evidence of a strong association between our ADR phenotype and ACEi-associated cough. Taken together, these findings increase insight into the pathophysiological processes that underlie ACEi-associated ADRs.

SBbadger: biochemical reaction networks with definable degree distributions

MOTIVATION

An essential step in developing computational tools for the inference, optimization and simulation of biochemical reaction networks is gauging tool performance against earlier efforts using an appropriate set of benchmarks. General strategies for the assembly of benchmark models include collection from the literature, creation via subnetwork extraction and de novo generation. However, with respect to biochemical reaction networks, these approaches and their associated tools are either poorly suited to generate models that reflect the wide range of properties found in natural biochemical networks or to do so in numbers that enable rigorous statistical analysis.

RESULTS

In this work, we present SBbadger, a python-based software tool for the generation of synthetic biochemical reaction or metabolic networks with user-defined degree distributions, multiple available kinetic formalisms and a host of other definable properties. SBbadger thus enables the creation of benchmark model sets that reflect properties of biological systems and generate the kinetics and model structures typically targeted by computational analysis and inference software. Here, we detail the computational and algorithmic workflow of SBbadger, demonstrate its performance under various settings, provide sample outputs and compare it to currently available biochemical reaction network generation software.

AVAILABILITY AND IMPLEMENTATION

SBbadger is implemented in Python and is freely available at https://github.com/sys-bio/SBbadger and via PyPI at https://pypi.org/project/SBbadger/. Documentation can be found at https://SBbadger.readthedocs.io.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

sconce: a cosmic web finder for spherical and conic geometries

The latticework structure known as the cosmic web provides a valuable insight into the assembly history of large-scale structures. Despite the variety of methods to identify the cosmic web structures, they mostly rely on the assumption that galaxies are embedded in a Euclidean geometric space. Here, we present a novel cosmic web identifier called sconce (Spherical and CONic Cosmic wEb finder) that inherently considers the 2D (RA, DEC) spherical or the 3D (RA, DEC, z) conic geometry. The proposed algorithms in sconce generalize the well-known subspace constrained mean shift (scms) method and primarily address the predominant filament detection problem. They are intrinsic to the spherical/conic geometry and invariant to data rotations. We further test the efficacy of our method with an artificial cross-shaped filament example and apply it to the SDSS galaxy catalogue, revealing that the 2D spherical version of our algorithms is robust even in regions of high declination. Finally, using N-body simulations from Illustris, we show that the 3D conic version of our algorithms is more robust in detecting filaments than the standard scms method under the redshift distortions caused by the peculiar velocities of haloes. Our cosmic web finder is packaged in python as sconce-scms and has been made publicly available.

Emergence of Dalbavancin, Vancomycin, and Daptomycin Nonsusceptible Staphylococcus aureus in a Patient Treated With Dalbavancin: Case Report and Isolate Characterization

A patient with end-stage renal disease received 2 doses of dalbavancin for methicillin-resistant Staphylococcus aureus (MRSA) arteriovenous fistula infection and presented 5 weeks later with infective endocarditis secondary to vancomycin, daptomycin, and dalbavancin nonsusceptible MRSA. Resistance was associated with walK and scrA mutations, reduced long-chain lipid content, and reduced membrane fluidity.

Advancing equity and justice through community science programming in design, construction, and research of a nature-based solution: the Duwamish Floating Wetlands Project

Dx^wdəw refers to the Black-Green Rivers confluences that made the Duwamish River in Seattle, Washington, USA, prior to the 1910s. Significant industrial activity and human-made diversions to these rivers caused heavy pollution and eliminated 97% of historic wetlands, forever altering the historic river systems, salmon runs and human and aquatic health. Today the Green-Duwamish River and Duwamish Estuary are an industrial and commercial corridor, albeit also a site of cultural significance and fishing rights for urban Indigenous and Coast Salish tribes, and home and workplace to diverse urban populations of sustenance fishers, immigrants and refugees, communities of color, and low-income neighborhoods. Using a socio-ecological and environmental justice perspective within a nature-based solution, the Duwamish Floating Wetlands Project designed and piloted four constructed floating wetland structures for two years on the Duwamish River and researched their feasibility to provide habitat for out-migrating juvenile salmon. A multi-pronged community team (community leaders, liaisons, stewards and scientists) worked alongside academics and professionals. This paper showcases the formulation and adaptation of a two-year citizen/community science program integrated into the project. We outline the frameworks, approach, outcomes, and lessons-learned of the community science and outreach program, and compiled these in a list of guidelines to provide practitioner, researcher and community insight into the value and necessity of prioritizing environmental justice, racial equity, and ecosystem needs in nature-based solutions.

Physiology assays in human kidney organoids

Kidney organoids derived from human pluripotent stem cells constitute a novel model of disease, development, and regenerative therapy. Organoids are human, experimentally accessible, high throughput, and enable reconstitution of tissue-scale biology in a petri dish. Although gene expression patterns in organoid cells have been analyzed extensively, less is known about the functionality of these structures. Here, we review assays of physiological function in human kidney organoids, including best practices for quality control, and future applications. Tubular structures in organoids accumulate specific molecules through active transport, including dextran and organic anions, and swell with fluid in response to cAMP stimulation. When engrafted into animal models in vivo, organoids form vascularized glomerulus-like structures capable of size-selective filtration. Organoids exhibit metabolic, endocrine, injury, and infection phenotypes, although their specificity is not yet fully clear. To properly interpret organoid physiology assays, it is important to incorporate appropriate negative and positive controls, statistical methods, data presentation, molecular mechanisms, and clinical data sets. Improvements in organoid perfusion, patterning, and maturation are needed to enable branching morphogenesis, urine production, and renal replacement. Reconstituting renal physiology with kidney organoids is a new field with potential to provide fresh insights into classical phenomena.

Potential impacts of Washington State's wildfire worker protection rule on construction workers

Driven by climate change, wildfires are increasing in frequency, duration, and intensity across the Western United States. Outdoor workers are being exposed to increasing wildfire-related particulate matter and smoke. Recognizing this emerging risk, Washington adopted an emergency rule and is presently engaged in creating a permanent rule to protect outdoor workers from wildfire smoke exposure. While there are growing bodies of literature on the exposure to and health effects of wildfire smoke in the general public and wildland firefighters, there is a gap in knowledge about wildfire smoke exposure among outdoor workers generally and construction workers specifically-a large category of outdoor workers in Washington totaling 200,000 people. Several data sources were linked in this study-including state-collected employment data and national ambient air quality data-to gain insight into the risk of PM2.5 exposure among construction workers and evaluate the impacts of different air quality thresholds that would have triggered a new Washington emergency wildfire smoke rule aimed at protecting workers from high PM2.5 exposure. Results indicate the number of poor air quality days has increased in August and September in recent years. Over the last decade, these months with the greatest potential for particulate matter exposure coincided with an annual peak in construction employment that was typically 9.4-42.7% larger across Washington counties (one county was 75.8%). Lastly, the 'encouraged' threshold of the Washington emergency rule (20.5 μg m-3) would have resulted in 5.5 times more days subject to the wildfire rule on average across all Washington counties compared to its 'required' threshold (55.5 μg m-3), and in 2020, the rule could have created demand for 1.35 million N-95 filtering facepiece respirators among construction workers. These results have important implications for both employers and policy makers as rules are developed. The potential policy implications of wildfire smoke exposure, exposure control strategies, and data gaps that would improve understanding of construction worker exposure to wildfire smoke are also discussed.

Skilled Nursing Facility Organizational Characteristics Are More Strongly Associated With Multiparticipant Therapy Provision Than Patient Characteristics

OBJECTIVES

Multiparticipant physical and occupational therapy provision has fluctuated significantly in skilled nursing facilities (SNFs) under shifts in Medicare reimbursement policy. Multiparticipant therapy includes group (2-6 individuals per therapist) and concurrent therapy (2 individuals per therapist). This study uses recent patient-level data to characterize multiparticipant therapy provision in SNFs to help anticipate shifts under new Medicare policy and the COVID-19 pandemic.

METHODS

This secondary analysis used data on 1,016,984 post-acute rehabilitation stays in SNFs in 2018. This analysis identified patient predictors (eg, demographic, clinical) and organizational predictors (eg, ownership, quality, staffing) of receiving multiparticipant therapy using mixed-effects logistic regression. Among individuals who received any multiparticipant therapy, those patient or facility factors associated with high rates of multiparticipant therapy provision were also determined.

RESULTS

Less than 3% of individuals received multiparticipant therapy in 2018. Patient functional and cognitive impairment and indicators of market regulation were associated with lower odds of multiparticipant therapy. Effect sizes for organizational factors associated with multiparticipant therapy provision were generally larger compared with patient factors. High multiparticipant therapy provision was concentrated in <2% of SNFs and was positively associated with for-profit ownership, contract staffing, and low 5-star quality ratings.

CONCLUSION

SNF organizational characteristics tended to have stronger associations with multiparticipant therapy provision than patient factors, suggesting that changes in patient case-mix, as expected during the COVID-19 pandemic, may have less of an impact on multiparticipant therapy provision than organizational factors. Results suggest that for-profit SNFs in states with higher market regulation, SNFs providing high volumes of therapy, and SNFs utilizing high proportions of assistants and contract staff may be more responsive to Medicare policy by increasing multiparticipant therapy provision.

IMPACT

This study may help identify SNFs that are more likely to increase multiparticipant therapy provision under new Medicare payment policy.

Androgens and estrogens predict sexual function after autologous hematopoietic stem cell transplant in men

BACKGROUND

Autologous hematopoietic stem cell transplantation (AHSCT) is associated with sexual dysfunction and hypogonadism. Androgens are associated with sexual function in healthy men, but the role of estrogens is less well-known, and the association of these sex steroids with sexual function during AHSCT has not been characterized.

OBJECTIVES

The purpose of this study was to determine the predictive value of sex hormones before and acutely after AHSCT on sexual function recovery.

MATERIALS AND METHODS

We examined sex hormones and self-reported sexual function before (PRE) and 1-month post-AHSCT (MONTH1; n = 19), and sexual function again 1-year post-AHSCT in men (YEAR1; n = 15).

RESULTS

Sexual function decreased from PRE to MONTH1 (p ≤ 0.05) with no differences between PRE and YEAR1. Erectile dysfunction was prevalent at PRE (68.4%) and increased at MONTH1 (100%; p ≤ 0.05) but was not different between PRE and YEAR1 (60.0%). From PRE to MONTH1, total testosterone (TT), dihydrotestosterone (DHT), follicle-stimulating hormone, and sex-hormone-binding globulin (SHBG) increased (p ≤ 0.02) while estradiol (p ≤ 0.026) and estrone decreased (p ≤ 0.001). MONTH1 TT and DHT were associated with sexual function at MONTH1, while PRE SHBG, MONTH1 estradiol, and change in estrone predicted sexual function at YEAR1.

DISCUSSION

Sexual dysfunction is very prevalent prior to AHSCT and is transiently and severely worsened acutely after. AHSCT induces acute decreases in total and free estrogens, with SHBG increases leading to increases in total androgens, without changes in free androgens.

CONCLUSION

Androgens and estrogens are both adversely affected by AHSCT but may predict sexual dysfunction in this population. This supports the premise that estrogen impacts sexual function independent from androgens and that steroid hormones are associated with acute changes in sexual function in this setting. Larger, controlled trials with long-term sex hormone assessment will need to confirm the association between early changes in estrogens and long-term sexual function recovery.

Osteoblasts pattern endothelium and somatosensory axons during zebrafish caudal fin organogenesis

Skeletal elements frequently associate with vasculature and somatosensory nerves, which regulate bone development and homeostasis. However, the deep, internal location of bones in many vertebrates has limited in vivo exploration of the neurovascular-bone relationship. Here, we use the zebrafish caudal fin, an optically accessible organ formed of repeating bony ray skeletal units, to determine the cellular relationship between nerves, bones and endothelium. In adult zebrafish, we establish the presence of somatosensory axons running through the inside of the bony fin rays, juxtaposed with osteoblasts on the inner hemiray surface. During development we show that the caudal fin progresses through sequential stages of endothelial plexus formation, bony ray addition, ray innervation and endothelial remodeling. Surprisingly, the initial stages of fin morphogenesis proceed normally in animals lacking either fin endothelium or somatosensory nerves. Instead, we find that sp7+ osteoblasts are required for endothelial remodeling and somatosensory axon innervation in the developing fin. Overall, this study demonstrates that the proximal neurovascular-bone relationship in the adult caudal fin is established during fin organogenesis and suggests that ray-associated osteoblasts pattern axons and endothelium.

Diaryliodonium Salts Facilitate Metal-Free Mechanoredox Free Radical Polymerizations

Mechanically-induced redox processes offer a promising alternative to more conventional thermal and photochemical synthetic methods. For macromolecule synthesis, current methods utilize sensitive transition metal additives and suffer from background reactivity....

Cell wall and cytoskeletal contributions in single cell biomechanics of Nicotiana tabacum

Studies on the mechanics of plant cells usually focus on understanding the effects of turgor pressure and properties of the cell wall (CW). While the functional roles of the underlying cytoskeleton have been studied, the extent to which it contributes to the mechanical properties of cells is not elucidated. Here, we study the contributions of the CW, microtubules (MTs) and actin filaments (AFs), in the mechanical properties of Nicotiana tabacum cells. We use a multiscale biomechanical assay comprised of atomic force microscopy and micro-indentation in solutions that (i) remove MTs and AFs and (ii) alter osmotic pressures in the cells. To compare measurements obtained by the two mechanical tests, we develop two generative statistical models to describe the cell's behaviour using one or both datasets. Our results illustrate that MTs and AFs contribute significantly to cell stiffness and dissipated energy, while confirming the dominant role of turgor pressure.

Stereoretentive and Regioselective Selenium-catalyzed Intermolecular Propargylic C-H Amination of Alkynes

Herein we report an intermolecular propargylic C–H amination of alkynes. This reaction is operationally convenient and requires no transition metal catalysts or additives. Terminal, silyl, and internal alkynes bearing a wide range of functional groups can be aminated in high yields. The regioselectivity of amination for unsymmetrical internal alkynes is strongly influenced by substitution pattern (tertiary > secondary > primary) and by relatively remote heteroatomic substituents. We demonstrate that amination of alkynes bearing α-stereocenters occurs with retention of configuration at the newly-formed C–N bond. Competition experiments between alkynes, kinetic isotope effects, and DFT calculations are performed to confirm the mechanistic hypothesis that initial ene reaction of a selenium bis(imide) species is the rate- and product-determining step. This ene reaction has a transition state that results in substantial partial positive charge development at the carbon atom closer to the amination position. Inductive and/or hyperconjugative stabilization or destabilization of this positive charge explains the observed regioselectivities.

Selenium catalysis enables a general intermolecular propargylic C–H amination of alkynes. The concerted mechanism gives rise to high regioselectivity for the more electron-rich end of the alkyne and retention of the C–H propargylic stereocenter.

Antigenic evolution of human influenza H3N2 neuraminidase is constrained by charge balancing

As one of the main influenza antigens, neuraminidase (NA) in H3N2 virus has evolved extensively for more than 50 years due to continuous immune pressure. While NA has recently emerged as an effective vaccine target, biophysical constraints on the antigenic evolution of NA remain largely elusive. Here, we apply combinatorial mutagenesis and next-generation sequencing to characterize the local fitness landscape in an antigenic region of NA in six different human H3N2 strains that were isolated around 10 years apart. The local fitness landscape correlates well among strains and the pairwise epistasis is highly conserved. Our analysis further demonstrates that local net charge governs the pairwise epistasis in this antigenic region. In addition, we show that residue coevolution in this antigenic region is correlated with the pairwise epistasis between charge states. Overall, this study demonstrates the importance of quantifying epistasis and the underlying biophysical constraint for building a model of influenza evolution.

Kinetochore-bound Mps1 regulates kinetochore-microtubule attachments via Ndc80 phosphorylation

Dividing cells detect and correct erroneous kinetochore-microtubule attachments during mitosis, thereby avoiding chromosome missegregation. The Aurora B kinase phosphorylates microtubule-binding elements specifically at incorrectly attached kinetochores, promoting their release and providing another chance for proper attachments to form. However, growing evidence suggests that the Mps1 kinase is also required for error correction. Here we directly examine how Mps1 activity affects kinetochore-microtubule attachments using a reconstitution-based approach that allows us to separate its effects from Aurora B activity. When endogenous Mps1 that copurifies with kinetochores is activated in vitro, it weakens their attachments to microtubules via phosphorylation of Ndc80, a major microtubule-binding protein. This phosphorylation contributes to error correction because phospho-deficient Ndc80 mutants exhibit genetic interactions and segregation defects when combined with mutants in other error correction pathways. In addition, Mps1 phosphorylation of Ndc80 is stimulated on kinetochores lacking tension. These data suggest that Mps1 provides an additional mechanism for correcting erroneous kinetochore-microtubule attachments, complementing the well-known activity of Aurora B.

Activated PI3Kδ signals compromise plasma cell survival via limiting autophagy and increasing ER stress

While phosphatidylinositide 3-kinase delta (PI3Kδ) plays a critical role in humoral immunity, the requirement for PI3Kδ signaling in plasma cells remains poorly understood. Here, we used a conditional mouse model of activated PI3Kδ syndrome (APDS), to interrogate the function of PI3Kδ in plasma cell biology. Mice expressing a PIK3CD gain-of-function mutation (aPIK3CD) in B cells generated increased numbers of memory B cells and mounted an enhanced secondary response but exhibited a rapid decay of antibody levels over time. Consistent with these findings, aPIK3CD expression markedly impaired plasma cell generation, and expression of aPIK3CD intrinsically in plasma cells was sufficient to diminish humoral responses. Mechanistically, aPIK3CD disrupted ER proteostasis and autophagy, which led to increased plasma cell death. Notably, this defect was driven primarily by elevated mTORC1 signaling and modulated by treatment with PI3Kδ-specific inhibitors. Our findings establish an essential role for PI3Kδ in plasma cell homeostasis and suggest that modulating PI3Kδ activity may be useful for promoting and/or thwarting specific immune responses.