Nitrate-dependent anaerobic methane oxidation coupled to Fe(III) reduction as a source of ammonium and nitrous oxide

'Candidatus Methanoperedens nitroreducens' is an archaeal methanotroph with global importance that links carbon and nitrogen cycles and great potential for sustainable operation of wastewater treatment. It has been reported to mediate the anaerobic oxidation of methane through a reverse methanogenesis pathway while reducing nitrate to nitrite. Here, we demonstrate that 'Ca. M. nitroreducens' reduces ferric iron forming ammonium (23.1 %) and nitrous oxide (N2O, 46.5 %) from nitrate. These results are supported with the upregulation of genes coding for proteins responsible for dissimilatory nitrate reduction to ammonium (nrfA), N2O formation (norV, cyt P460), and multiple multiheme c-type cytochromes for ferric iron reduction. Concomitantly, an increase in the N2O-reducing SJA-28 lineage and a decrease in the nitrite-reducing 'Candidatus Methylomirabilis oxyfera' are consistent with the changes in 'Ca. M. nitroreducens' end products. These findings demonstrate the highly flexible physiology of 'Ca. M. nitroreducens' in anaerobic ecosystems with diverse electron acceptor conditions, and further reveals its roles in linking methane oxidation to global biogeochemical cycles. 'Ca. M. nitroreducens' could significantly affect the bioavailability of nitrogen sources as well as the emission of greenhouse gas in natural ecosystems and wastewater treatment plants.

Biosynthesis of a new skyllamycin in Streptomyces nodosus: a cytochrome P450 forms an epoxide in the cinnamoyl chain

Activation of a silent gene cluster in Streptomyces nodosus leads to synthesis of a cinnamoyl-containing non-ribosomal peptide (CCNP) that is related to skyllamycins. This novel CCNP was isolated and its structure was interrogated using mass spectrometry and nuclear magnetic resonance spectroscopy. The isolated compound is an oxidised skyllamycin A in which an additional oxygen atom is incorporated in the cinnamoyl side-chain in the form of an epoxide. The gene for the epoxide-forming cytochrome P450 was identified by targeted disruption. The enzyme was overproduced in Escherichia coli and a 1.43 Å high-resolution crystal structure was determined. This is the first crystal structure for a P450 that forms an epoxide in a substituted cinnamoyl chain of a lipopeptide. These results confirm the proposed functions of P450s encoded by biosynthetic gene clusters for other epoxidized CCNPs and will assist investigation of how epoxide stereochemistry is determined in these natural products.

Kinetic, electrochemical and spectral characterization of bacterial and archaeal rusticyanins; unexpected stability issues and consequences for applications in biotechnology

Motivated by the ambition to establish an enzyme-driven bioleaching pathway for copper extraction, properties of the Type-1 copper protein rusticyanin from Acidithiobacillus ferrooxidans (AfR) were compared with those from an ancestral form of this enzyme (N0) and an archaeal enzyme identified in Ferroplasma acidiphilum (FaR). While both N0 and FaR show redox potentials similar to that of AfR their electron transport rates were significantly slower. The lack of a correlation between the redox potentials and electron transfer rates indicates that AfR and its associated electron transfer chain evolved to specifically facilitate the efficient conversion of the energy of iron oxidation to ATP formation. In F. acidiphilum this pathway is not as efficient unless it is up-regulated by an as of yet unknown mechanism. In addition, while the electrochemical properties of AfR were consistent with previous data, previously unreported behavior was found leading to a form that is associated with a partially unfolded form of the protein. The cyclic voltammetry (CV) response of AfR immobilized onto an electrode showed limited stability, which may be connected to the presence of the partially unfolded state of this protein. Insights gained in this study may thus inform the engineering of optimized rusticyanin variants for bioleaching processes as well as enzyme-catalyzed solubilization of copper-containing ores such as chalcopyrite.

Predicting cytopenias, progression, and survival in patients with clonal cytopenia of undetermined significance: a prospective cohort study

BACKGROUND

Somatic mutations are frequently reported in individuals with cytopenia but without a confirmed haematological diagnosis (clonal cytopenia of undetermined significance; CCUS). These patients have an increased risk of progression to a myeloid malignancy and worse overall survival than those with no such mutations. To date, studies have been limited by retrospective analysis or small patient numbers. We aimed to establish the natural history of CCUS by prospectively investigating outcome in a large, well defined patient cohort.

METHODS

This prospective cohort study was conducted at the Haematological Malignancy Diagnostic Service, a diagnostic laboratory in Leeds, UK. Patients aged at least 18 years who were referred for investigation of cytopenia were eligible for inclusion; those with a history of myeloid malignancy were not eligible. Targeted sequencing was conducted alongside routine clinical testing. Baseline mutation analysis was then correlated with the main study outcomes: longitudinal blood counts, disease progression to a myeloid malignancy, and overall survival with a median follow-up of 4·54 years (IQR 4·03-5·04). Data were collected manually from hospital records or extracted from laboratory or clinical outcome databases.

FINDINGS

Bone marrow samples from 2348 patients were received at the Haematological Malignancy Diagnostic Service between July 1, 2014, and July 31, 2016. Of these, 2083 patients (median age 72 years [IQR 63-80, range 18-99]; 854 [41·0%] female and 1229 [59·0%] male) met the inclusion criteria and had samples of sufficient quality for further analysis. 598 (28·7%) patients received a diagnosis on the basis of their biopsy sample, whereas 1485 (71·3%) samples were classified as non-diagnostic; of these, CCUS was confirmed in 400 (26·9%) patients (256 [64·0%] male and 144 [36·0%] female). TET2, SRSF2, and DNMT3A were the most frequently mutated genes in patients with CCUS, with 320 (80%) of 400 patients harbouring a mutation in at least one of these genes. Age (p<0·0001), sex (p=0·0027), and mutations in ASXL1 (p=0·0009), BCOR (p=0·0056), and TP53 (p=0·0055) correlated with a worse overall survival; however, the number of mutations was the strongest predictor for progression to a myeloid malignancy (two mutations, p=0·0024; three or more mutations, p=0·0004). Extended sequencing of samples from a subgroup of patients with sequential samples and no mutations in the initial myeloid gene panel showed recurrent mutations in both DDX41 and UBA1, suggesting that these genes should be included in clinical test panels.

INTERPRETATION

Mutation analysis is advised in patients who have undergone bone marrow examination and have an otherwise-unexplained cytopenia. High-risk genetic mutations and increased numbers of mutations are predictive of both survival and progression within 5 years of presentation, warranting clinical surveillance and, when necessary, intervention.

FUNDING

MDS Foundation.

Evidence for Nitrous Oxide Emissions by Nitrite-Dependent Anaerobic Methane Oxidizing Bacteria

Nitrite-dependent anaerobic methane oxidizing (n-DAMO) bacteria generally convert nitrite to dinitrogen and bypass the nitrous oxide (N2O) formation step. However, N2O is often detected in n-DAMO bacteria dominated cultures and it remains an open question as to the microbial origin of N2O in these enrichments. Using a stable nitrite consuming microbial community enriched for n-DAMO bacteria, we demonstrated that N2O production was coupled to methane oxidation and the higher initial nitrite concentrations led to increased quantities of N2O being formed. Moreover, continuous exposure of the enrichment culture to about 5 mg of N L-1 nitrite resulted in constant N2O being produced (12.5% of nitrite was reduced to N2O). Metatranscriptomic analyses revealed that nitrite reductase (nirS) and nitric oxide reductase (norZ) transcripts from n-DAMO bacteria increased in response to nitrite exposure. No other bacteria significantly expressed nor genes under these conditions, suggesting n-DAMO bacteria are responsible for N2O being produced. In a 35-day bioreactor experiment, N2O produced by the n-DAMO bacteria accumulated when nitrite was in excess; this was found to be up to 3.2% of the nitrogen that resulted from nitrite removal. Together, these results suggested that excess nitrite is an important driver of N2O production by n-DAMO bacteria. To this end, proper monitoring and control of nitrite levels in wastewater treatment plants would be effective strategies for mitigating N2O emissions to the atmosphere.

Anthropedogenesis in coal mine overburden; the need for a comprehensive, fundamental biogeochemical approach

The primary solid waste product of surface coal mining is overburden (also known as spoil), the material that is moved to access the underlying coal seams. Once removed, this material is generally stored in large (>100 m in height) piles until it is re-contoured in preparation for post-mining rehabilitation, often remaining there for decades. Under ideal conditions, these new landforms would have at least 30 cm veneer of topsoil applied as a growth medium for plants. However, topsoil deficit conditions are common in coal mines, so the forced use of overburden that possess poor chemical, biological, and physical properties as the growth medium hinders plant establishment. To reach the characteristics of a functional soil that can support plants, it is necessary to dramatically improve spoil quality, i.e., accelerate pedogenesis, as an integral part of the rehabilitation process. For decades, overburden rehabilitation has often taken the traditional approach of using the agricultural practice of fertilizer application or focusing primarily on the types of plants used to stabilize these young landforms. In contrast, success improved when the rehabilitation procedures employed a more holistic approach to establishing self-sustaining plant-soil ecosystems. Here we identify constraints that impede spoil-to-soil transformation, discuss the global treatment options practiced post-mining for coal spoils, and describe how a comprehensive biogeochemical approach can be implemented in spoil reclamation processes going forward. Integrating the revitalization of soil organisms, reclamation of soil chemistry, soil structure, and landform into rehabilitation procedures can accelerate the transformation of coal spoils to functional soils. We believe that a shift in the nature of the question from "what chemicals and seeds should we add to coal spoil during site rehabilitation?" to something fundamentally more specific: "How do we induce pedogenic functions in coal spoils to develop fertile soils?" is needed.

Hot spring distribution and survival mechanisms of thermophilic comammox Nitrospira

The recent discovery of Nitrospira species capable of complete ammonia oxidation (comammox) in non-marine natural and engineered ecosystems under mesothermal conditions has changed our understanding of microbial nitrification. However, little is known about the occurrence of comammox bacteria or their ability to survive in moderately thermal and/or hyperthermal habitats. Here, we report the wide distribution of comammox Nitrospira in five terrestrial hot springs at temperatures ranging from 36 to 80°C and provide metagenome-assembled genomes of 11 new comammox strains. Interestingly, the identification of dissimilatory nitrate reduction to ammonium (DNRA) in thermophilic comammox Nitrospira lineages suggests that they have versatile ecological functions as both sinks and sources of ammonia, in contrast to the described mesophilic comammox lineages, which lack the DNRA pathway. Furthermore, the in situ expression of key genes associated with nitrogen metabolism, thermal adaptation, and oxidative stress confirmed their ability to survive in the studied hot springs and their contribution to nitrification in these environments. Additionally, the smaller genome size and higher GC content, less polar and more charged amino acids in usage profiles, and the expression of a large number of heat shock proteins compared to mesophilic comammox strains presumably confer tolerance to thermal stress. These novel insights into the occurrence, metabolic activity, and adaptation of comammox Nitrospira in thermal habitats further expand our understanding of the global distribution of comammox Nitrospira and have significant implications for how these unique microorganisms have evolved thermal tolerance strategies.

Conical shell illumination incorporating a moving aperture for depth-resolved high-energy X-ray diffraction

In many applications, the main limitation of X-ray absorption methods is that the signals measured are a function of the attenuation coefficient, which tells us almost nothing about the chemical or crystallographic nature of objects under inspection. To calculate fundamental crystallographic parameters requires the measurement of diffracted photons from a sample. Standard laboratory diffraction methods have been refined for well over a century and provide 'gold standard' structural models for well-prepared samples and single crystals but have little applicability for thick heterogeneous samples as demanded by many screening applications. We present a new high-energy X-ray diffraction probe, which in comparison with previous depth-resolving hollow beam techniques, requires a single beam, point detector and a simple swept aperture to resolve sample signatures at unknown locations within an inspection space. We perform Monte Carlo simulations to support experiments on both single- and multiple-material localisation and identification. The new probe is configured and tested using low-cost commercial components to provide a rapid and cost-effective solution for applications including explosives detection, process control and diagnostics.

Translational opportunities of single-cell biology in atherosclerosis

The advent of single-cell biology opens a new chapter for understanding human biological processes and for diagnosing, monitoring, and treating disease. This revolution now reaches the field of cardiovascular disease (CVD). New technologies to interrogate CVD samples at single-cell resolution are allowing the identification of novel cell communities that are important in shaping disease development and direct towards new therapeutic strategies. These approaches have begun to revolutionize atherosclerosis pathology and redraw our understanding of disease development. This review discusses the state-of-the-art of single-cell analysis of atherosclerotic plaques, with a particular focus on human lesions, and presents the current resolution of cellular subpopulations and their heterogeneity and plasticity in relation to clinically relevant features. Opportunities and pitfalls of current technologies as well as the clinical impact of single-cell technologies in CVD patient care are highlighted, advocating for multidisciplinary and international collaborative efforts to join the cellular dots of CVD.

Epigenetic regulator genes direct lineage switching in MLL/AF4 leukemia

The fusion gene MLL/AF4 defines a high-risk subtype of pro-B acute lymphoblastic leukemia. Relapse can be associated with a lineage switch from acute lymphoblastic to acute myeloid leukemia, resulting in poor clinical outcomes caused by resistance to chemotherapies and immunotherapies. In this study, the myeloid relapses shared oncogene fusion breakpoints with their matched lymphoid presentations and originated from various differentiation stages from immature progenitors through to committed B-cell precursors. Lineage switching is linked to substantial changes in chromatin accessibility and rewiring of transcriptional programs, including alternative splicing. These findings indicate that the execution and maintenance of lymphoid lineage differentiation is impaired. The relapsed myeloid phenotype is recurrently associated with the altered expression, splicing, or mutation of chromatin modifiers, including CHD4 coding for the ATPase/helicase of the nucleosome remodelling and deacetylation complex. Perturbation of CHD4 alone or in combination with other mutated epigenetic modifiers induces myeloid gene expression in MLL/AF4+ cell models, indicating that lineage switching in MLL/AF4 leukemia is driven and maintained by disrupted epigenetic regulation.

Reduction of Substituted Benzo-Fused Cyclic Sulfonamides with Mg-MeOH: An Experimental and Computational Study

A study involving the use of Mg-MeOH for the double reductive cleavage of both N–S and C–S bonds in a series of 11 benzo-fused cyclic sulfonamides is reported. Examples where the sulfonamide nitrogen atom is part of a pyrrolidine ring effectively undergo reduction, as long as a methoxy substituent is not para-positioned in the aromatic ring, relative to the sulfonyl group. In contrast, if the nitrogen atom is contained within an aromatic ring (pyrrole or indole), the presence of a para-methoxy substituent does not prohibit reduction. If deuterated methanol is used, aromatic ortho-deuterium incorporation was observed. To better understand how structure affects reactivity, density functional theory calculations were performed using three functionals. Results using CAM-B3LYP were found to best correlate with experimental observations, and these demonstrate the impact that the different aromatic substitution patterns and types of N-atom have on the lowest unoccupied molecular orbital (LUMO) energies and adiabatic electron affinities.

Interpretation and actionability of genetic variants in cardiomyopathies: a position statement from the European Society of Cardiology Council on cardiovascular genomics

This document describes the contribution of clinical criteria to the interpretation of genetic variants using heritable Mendelian cardiomyopathies as an example. The aim is to assist cardiologists in defining the clinical contribution to a genetic diagnosis and the interpretation of molecular genetic reports. The identification of a genetic variant of unknown or uncertain significance is a limitation of genetic testing, but current guidelines for the interpretation of genetic variants include essential contributions from clinical family screening that can establish a de novo assignment of the variant or its segregation with the phenotype in the family. A partnership between clinicians and patients helps to solve major uncertainties and provides reliable and clinically actionable information.

Stereoselective synthesis of analogues of deoxyfebrifugine

The preparation of six new optically active analogues of the natural product febrifugine (1) is reported. These analogues, lacking the hydroxy group from the natural product, were prepared from optically active N-protected S-pelletierine (7) and differ in terms of the specific quinazolinone portion included. The required S-7 (80% enantiomeric excess) was prepared from an asymmetric Mannich reaction between piperideine (8) and acetone in the presence of l-proline. The differently substituted quinazolinone used in this study (10a–10g) was either commercially available or was prepared from the corresponding substituted anthranilic acid and were installed via a bromination–alkylation sequence. N-Deprotection of the subsequent adducts (12a–12g) gave target compounds 13a–13f and completed the synthetic sequence.

Gadolinium: pharmacokinetics and toxicity in humans and laboratory animals following contrast agent administration

Gadolinium-based contrast agents (GBCAs) have transformed magnetic resonance imaging (MRI) by facilitating the use of contrast-enhanced MRI to allow vital clinical diagnosis in a plethora of disease that would otherwise remain undetected. Although over 500 million doses have been administered worldwide, scientific research has documented the retention of gadolinium in tissues, long after exposure, and the discovery of a GBCA-associated disease termed nephrogenic systemic fibrosis, found in patients with impaired renal function. An understanding of the pharmacokinetics in humans and animals alike are pivotal to the understanding of the distribution and excretion of gadolinium and GBCAs, and ultimately their potential retention. This has been well studied in humans and more so in animals, and recently there has been a particular focus on potential toxicities associated with multiple GBCA administration. The purpose of this review is to highlight what is currently known in the literature regarding the pharmacokinetics of gadolinium in humans and animals, and any toxicity associated with GBCA use.

Asymmetric Synthesis of γ-Amino-Functionalised Vinyl Sulfones: De Novo Preparation of Cysteine Protease Inhibitors

The enantioselective azo-based α-amination of an aldehyde followed by a Horner–Wadsworth–Emmons-based vinyl sulfone formation is reported. The thus obtained optically active N,N′-diprotected trans-(phenylsulfonyl)vinyl hydrazine products were then converted into the corresponding N-functionalised trans-(phenylsulfonyl)vinyl amines. Specifically, reaction of 4-phenylbutanal with di-tert-butyl azodicarboxylate (DBAD) in the presence of l- or d-proline, followed by addition of diethyl [(phenylsulfonyl)methyl]phosphonate, gave either enantiomer of di-tert-butyl trans-1-[5-phenyl-1-(phenylsulfonyl)pent-1-en-3-yl]hydrazine-1,2-dicarboxylate. The enantiomeric excesses of the (+)- and (–)-enantiomers prepared in this manner were in the range 86–89%. The conversion of these γ-hydrazino vinyl sulfones into the corresponding γ-amino-substituted compounds was achieved following a Boc deprotection, Zn reduction, N-functionalisation sequence. This three-step sequence was reasonably efficient (approx. 50%) and no erosion of enantiopurity was found to have taken place. The compounds accessed via this process include both enantiomers of tert-butyl trans-[5-phenyl-1-(phenylsulfonyl)pent-1-en-3-yl]carbamate and epimeric dipeptide mimetics including 4-methyl-N-{(S)-1-oxo-3-phenyl-1-[((S,E)-5-phenyl-1-(phenylsulfonyl)pent-1-en-3-yl)amino]propan-2-yl}piperazine-1-carboxamide (also known as K777).

Carbon Monoxide Releasing Molecule A1 Reduces Myocardial Damage After Acute Myocardial Infarction in a Porcine Model

ABSTRACT

Infarct size is a major determinant of outcomes after acute myocardial infarction (AMI). Carbon monoxide-releasing molecules (CORMs), which deliver nanomolar concentrations of carbon monoxide to tissues, have been shown to reduce infarct size in rodents. We evaluated efficacy and safety of CORM-A1 to reduce infarct size in a clinically relevant porcine model of AMI. We induced AMI in Yorkshire White pigs by inflating a coronary angioplasty balloon to completely occlude the left anterior descending artery for 60 minutes, followed by deflation of the balloon to mimic reperfusion. Fifteen minutes after balloon occlusion, animals were given an infusion of 4.27 mM CORM-A1 (n = 7) or sodium borate control (n = 6) over 60 minutes. Infarct size, cardiac biomarkers, ejection fraction, and hepatic and renal function were compared amongst the groups. Immunohistochemical analyses were performed to compare inflammation, cell proliferation, and apoptosis between the groups. CORM-A1-treated animals had significant reduction in absolute infarct area (158 ± 16 vs. 510 ± 91 mm2, P < 0.001) and infarct area corrected for area at risk (24.8% ± 2.6% vs. 45.2% ± 4.0%, P < 0.0001). Biochemical markers of myocardial injury also tended to be lower and left ventricular function tended to recover better in the CORM-A1 treated group. There was no evidence of hepatic or renal toxicity with the doses used. The cardioprotective effects of CORM-A1 were associated with a significant reduction in cell proliferation and inflammation. CORM-A1 reduces infarct size and improves left ventricular remodeling and function in a porcine model of reperfused MI by a reduction in inflammation. These potential cardioprotective effects of CORMs warrant further translational investigations.

An enantiodivergent synthesis of N-Boc-protected (R)- and (S)-4-amino cyclopent-2-en-1-one

Routes are reported for the synthesis of both (1 R)- and (1 S)- tert-butyl-(4-oxocyclopent-2-en-1-yl)carbamate 2. Featuring Mitsunobu reactions with di- tert-butyl iminodicarbonate, both syntheses begin from ( S)-4-[( tert-butyldimethylsilyl)oxy]cyclopent-2-en-1-one (3) and take advantage of the 1,4-cyclopentenyl dioxygenation pattern of this optically active starting material. Thus both (−)- and (+)-2 have been accessed from 3 in an enantiodivergent manner in 11% and 10% overall yield over five and seven reaction steps, respectively.

The year in basic vascular biology research: from mechanoreceptors and neutrophil extracellular traps to smartphone data and omics

2020 has been an extraordinary year. The emergence of COVID-19 has driven urgent research in pulmonary and cardiovascular science and other fields. It has also shaped the way that we work with many experimental laboratories shutting down for several months, while bioinformatics approaches and other large data projects have gained prominence. Despite these setbacks, vascular biology research is stronger than ever. On behalf of the European Society of Cardiology Council for Basic Cardiovascular Science (ESC CBCS), here we review some of the vascular biology research highlights for 2020. This review is not exhaustive and there are many outstanding vascular biology publications that we were unable to cite due to page limits. Notwithstanding this, we have provided a snapshot of vascular biology research excellence in 2020 and identify topics that are in the ascendency and likely to gain prominence in coming years.

Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.

Evaluation of a worldwide EQA scheme for complex clonality analysis of clinical lymphoproliferative cases demonstrates a learning effect

Clonality analysis of immunoglobulin (IG) or T-cell receptor (TR) gene rearrangements is routine practice to assist diagnosis of lymphoid malignancies. Participation in external quality assessment (EQA) aids laboratories in identifying systematic shortcomings. The aim of this study was to evaluate laboratories' improvement in IG/TR analysis and interpretation during five EQA rounds between 2014 and 2018. Each year, participants received a total of five cases for IG and five cases for TR testing. Paper-based cases were included for analysis of the final molecular conclusion that should be interpreted based on the integration of the individual PCR results. Wet cases were distributed for analysis of their routine protocol as well as evaluation of the final molecular conclusion. In total, 94.9% (506/533) of wet tests and 97.9% (829/847) of paper tests were correctly analyzed for IG, and 96.8% (507/524) wet tests and 93.2% (765/821) paper tests were correctly analyzed for TR. Analysis scores significantly improved when laboratories participated to more EQA rounds (p=0.001). Overall performance was significantly lower (p=0.008) for non-EuroClonality laboratories (95% for IG and 93% for TR) compared to EuroClonality laboratories (99% for IG and 97% for TR). The difference was not related to the EQA scheme year, anatomic origin of the sample, or final clinical diagnosis. This evaluation showed that repeated EQA participation helps to reduce performance differences between laboratories (EuroClonality versus non-EuroClonality) and between sample types (paper versus wet). The difficulties in interpreting oligoclonal cases highlighted the need for continued education by meetings and EQA schemes.

Endothelial NADPH oxidase 4 protects against angiotensin II-induced cardiac fibrosis and inflammation

Aims

Endothelial activation and inflammatory cell infiltration have important roles in the development of cardiac fibrosis induced by renin–angiotensin system activation. NADPH oxidases (Nox proteins) are expressed in endothelial cells (ECs) and alter their function. Previous studies indicated that Nox2 in ECs contributes to angiotensin II (AngII)‐induced cardiac fibrosis. However, the effects of EC Nox4 on cardiac fibrosis are unknown.

Methods and results

Transgenic (TG) mice overexpressing endothelial‐restricted Nox4 were studied alongside wild‐type (WT) littermates as controls. At baseline, Nox4 TG mice had significantly enlarged hearts compared with WT, with elongated cardiomyocytes (increased by 18.5%, P < 0.01) and eccentric hypertrophy but well‐preserved cardiac function by echocardiography and in vivo pressure–volume analysis. Animals were subjected to a chronic AngII infusion (AngII, 1.1 mg/kg/day) for 14 days. Whereas WT/AngII developed a 2.1‐fold increase in interstitial cardiac fibrosis as compared with WT/saline controls (P < 0.01), TG/AngII mice developed significant less fibrosis (1.4‐fold increase, P > 0.05), but there were no differences in cardiac hypertrophy or contractile function between the two groups. TG hearts displayed significantly decreased inflammatory cell infiltration with reduced levels of vascular cell adhesion molecule 1 in both the vasculature and myocardium compared with WT after AngII treatment. TG microvascular ECs stimulated with AngII in vitro supported significantly less leukocyte adhesion than WT ECs.

Conclusions

A chronic increase in endothelial Nox4 stimulates physiological cardiac hypertrophy and protects against AngII‐induced cardiac fibrosis by inhibiting EC activation and the recruitment of inflammatory cells.

Mice with endothelium‐specific overexpression of Nox4 (EndoNox4 TG) exhibit eccentric hypertrophy with well‐preserved cardiac function at baseline.

EndoNox4 TG mice develop significantly less interstitial cardiac fibrosis in response to chronic pressure AngII stimulation, independent of cardiac hypertrophy.

Overexpression of Nox4 in endothelial cells reduces AngII‐induced endothelial activation.

An increase in endothelial Nox4 inhibits AngII‐induced recruitment of inflammatory cells in the heart.

Genome-wide association study identifies risk loci for progressive chronic lymphocytic leukemia

Prognostication in patients with chronic lymphocytic leukemia (CLL) is challenging due to heterogeneity in clinical course. We hypothesize that constitutional genetic variation affects disease progression and could aid prognostication. Pooling data from seven studies incorporating 842 cases identifies two genomic locations associated with time from diagnosis to treatment, including 10q26.13 (rs736456, hazard ratio (HR) = 1.78, 95% confidence interval (CI) = 1.47-2.15; P = 2.71 × 10-9) and 6p (rs3778076, HR = 1.99, 95% CI = 1.55-2.55; P = 5.08 × 10-8), which are particularly powerful prognostic markers in patients with early stage CLL otherwise characterized by low-risk features. Expression quantitative trait loci analysis identifies putative functional genes implicated in modulating B-cell receptor or innate immune responses, key pathways in CLL pathogenesis. In this work we identify rs736456 and rs3778076 as prognostic in CLL, demonstrating that disease progression is determined by constitutional genetic variation as well as known somatic drivers.

Synthesis and optimisation of P3 substituted vinyl sulfone-based inhibitors as anti-trypanosomal agents

A series of lysine-based vinyl sulfone peptidomimetics were synthesised and evaluated for anti-trypanosomal activity against bloodstream forms of T. brucei. This focused set of compounds, varying in the P₃ position, were accessed in a divergent manner from a common intermediate (ammonium salt 8). Several P₃ analogues exhibited sub-micromolar EC₅₀ values, with thiourea 14, urea 15 and amide 21 representing the most potent anti-trypanosomal derivatives of the series. In order to establish an in vitro selectivity index the most active anti-trypanosomal compounds were also assessed for their impact on cell viability and cytotoxity effects in mammalian cells. Encouragingly, all compounds only reduced cellular metabolic activity in mammalian cells to a modest level and little, or no cytotoxicity, was observed with the series.

Synthesis of 2-guanidinyl pyridines and their trypsin inhibition and docking

A range of guanidine-based pyridines, and related compounds, have been prepared (19 examples). These compounds were evaluated in relation to their competitive inhibition of bovine pancreatic trypsin. Results demonstrate that compounds in which the guanidinyl substituent can form an intramolecular hydrogen bond (IMHB) with the pyridinyl nitrogen atom (6a-p) are better trypsin inhibitors than their counterparts (10-13) that are unable to form an IMHB. Among the compounds 6a-p, examples containing a 5-halo substituent were, generally, found to be better trypsin inhibitors. This trend was inversely related to electronegativity, thus, 1-(5-iodopyridin-2-yl)guanidinium ion 6e (K_i = 0.0151 mM) was the optimum inhibitor in the 5-halo series. Amongst the isomeric methyl substituted compounds, 1-(3-methylpyridin-2-yl)guanidinium ion 6h demonstrated optimum levels of trypsin inhibition (K_i = 0.0140 mM). In order to rationalise the measured enzyme inhibition, selected compounds were docked with bovine and human trypsin with a view to understanding active site occupancy and taken together with the K_i values the order of inhibitory ability suggests that the 5-halo 2-guanidinyl pyridine inhibitors form a halogen bond with the catalytically active serine hydroxy group.

A new parafocusing paradigm for X-ray diffraction

A new approach to parafocusing X-ray diffraction implemented with an annular incident beam is demonstrated for the first time. The method exploits an elliptical specimen path on a flat sample to produce relatively high intensity maxima that can be measured with a point detector. It is shown that the flat-specimen approximation tolerated by conventional Bragg–Brentano geometries is not required. A theoretical framework, simulations and experimental results for both angular- and energy-dispersive measurement modes are presented and the scattering signatures compared with data obtained with a conventional pencil-beam arrangement.

TLR-mediated activation of Waldenström macroglobulinemia B cells reveals an uncoupling from plasma cell differentiation

Waldenström macroglobulinemia (WM) is a rare malignancy in which clonal B cells infiltrate the bone marrow and give rise to a smaller compartment of neoplastic plasma cells that secrete monoclonal immunoglobulin M paraprotein. Recent studies into underlying mutations in WM have enabled a much greater insight into the pathogenesis of this lymphoma. However, there is considerably less characterization of the way in which WM B cells differentiate and how they respond to immune stimuli. In this study, we assess WM B-cell differentiation using an established in vitro model system. Using T-cell-dependent conditions, we obtained CD138+ plasma cells from WM samples with a frequency similar to experiments performed with B cells from normal donors. Unexpectedly, a proportion of the WM B cells failed to upregulate CD38, a surface marker that is normally associated with plasmablast transition and maintained as the cells proceed with differentiation. In normal B cells, concomitant Toll-like receptor 7 (TLR7) activation and B-cell receptor cross-linking drives proliferation, followed by differentiation at similar efficiency to CD40-mediated stimulation. In contrast, we found that, upon stimulation with TLR7 agonist R848, WM B cells failed to execute the appropriate changes in transcriptional regulators, identifying an uncoupling of TLR signaling from the plasma cell differentiation program. Provision of CD40L was sufficient to overcome this defect. Thus, the limited clonotypic WM plasma cell differentiation observed in vivo may result from a strict requirement for integrated activation.

Student Vitality, Teacher Engagement, and Rapport in Studio Music Instruction

Vitality is the feeling of being alive, vigorous, and energetic, and is an important indicator of overall motivation and wellbeing. Studio music instruction holds rich potential for creating feelings of vitality through close relationships, the potential for developing skills, and a shared endeavor of artistic expression. But they also have the potential to deplete vitality – through controlling teaching, a poor quality relationship, or harsh criticism from the teacher. The purpose of this study was to investigate relationships among student and teacher behavior, rapport, and students’ experiences of subjective vitality in the context of university-level applied performance lessons. Participants were six undergraduate instrumental music majors and their teachers located at universities in the United States and Australia, who were selected because they provided the highest (three participants) and lowest (three participants) scores on a measure of subjective vitality completed immediately following a studio music lesson. A lesson was recorded for each student-teacher participant pair, coded for the frequencies of 35 lesson behaviors, described with a qualitative contextual commentary, and rated for evidence of rapport and physical proximity. Clear differences emerged between the high and low vitality lessons with regard to questioning, feedback, modeling, student performance, and student talk. Teachers of high vitality students spent most or all of the lesson within close proximity to their student, and showed stronger rapport than teachers of low vitality students. The findings suggest that students’ vitality may depend on important differences in styles of teacher-student engagement and the quality of student-teacher relationships.

A Simple Zinc-Mediated Method for Selenium Addition to Michael Acceptors

In this work, we focused our attention on seleno-Michael type reactions. These were performed using zinc-selenolates generated in situ from diphenyl diselenide 1, 1,2-bis(3-phenylpropyl)diselenide 30, and protected selenocystine 31 via an efficient biphasic Zn/HCl-based reducing system. Alkenes with a variety of electron-withdrawing groups were investigated in order to gauge the scope and limitations of the process. Results demonstrated that the addition to acyclic α,β-unsaturated ketones, aldehydes, esters amides, and acids was effectively achieved and that alkyl substituents at the reactive β-centre can be accommodated. Similarly, cyclic enones undergo efficient Se-addition and the corresponding adducts were isolated in moderate to good yield. Vinyl sulfones, α,β-unsaturated nitriles, and chalcones are not compatible with these reaction conditions. A recycling experiment demonstrated that the unreacted Zn/HCl reducing system can be effectively reused for seven reaction cycles (91% conversion yield at the 7° recycling rounds).

GATA4-Twist1 Signalling in Disturbed Flow-Induced Atherosclerosis

BACKGROUND

Endothelial cell (EC) dysfunction (enhanced inflammation, proliferation and permeability) is the initial trigger for atherosclerosis. Atherosclerosis shows preferential development near branches and bends exposed to disturbed blood flow. By contrast, sites that are exposed to non-disturbed blood flow are atheroprotected. Disturbed flow promotes atherosclerosis by promoting EC dysfunction. Blood flow controls EC function through transcriptional and post-transcriptional mechanisms that are incompletely understood.

METHODS AND RESULTS

We identified the developmental transcription factors Twist1 and GATA4 as being enriched in EC at disturbed flow, atheroprone regions of the porcine aorta in a microarray study. Further work using the porcine and murine aortae demonstrated that Twist1 and GATA4 expression was enhanced at the atheroprone, disturbed flow sites in vivo. Using controlled in vitro flow systems, the expression of Twist1 and GATA4 was enhanced under disturbed compared to non-disturbed flow in cultured cells. Disturbed flow promoted Twist1 expression through a GATA4-mediated transcriptional mechanism as revealed by a series of in vivo and in vitro studies. GATA4-Twist1 signalling promoted EC proliferation, inflammation, permeability and endothelial-to-mesenchymal transition (EndoMT) under disturbed flow, leading to atherosclerosis development, as shown in a combination of in vitro and in vivo studies using GATA4 and Twist1-specific siRNA and EC-specific GATA4 and Twist1 Knock out (KO) mice.

CONCLUSIONS

We revealed that GATA4-Twist1-Snail signalling triggers EC dysfunction and atherosclerosis; this work could lead to the development of novel anti-atherosclerosis therapeutics.

Integrative analysis of spontaneous CLL regression highlights genetic and microenvironmental interdependency in CLL

Spontaneous regression is a recognized phenomenon in chronic lymphocytic leukemia (CLL) but its biological basis remains unknown. We undertook a detailed investigation of the biological and clinical features of 20 spontaneous CLL regression cases incorporating phenotypic, functional, transcriptomic, and genomic studies at sequential time points. All spontaneously regressed tumors were IGHV-mutated with no restricted IGHV usage or B-cell receptor (BCR) stereotypy. They exhibited shortened telomeres similar to nonregressing CLL, indicating prior proliferation. They also displayed low Ki-67, CD49d, cell-surface immunoglobulin M (IgM) expression and IgM-signaling response but high CXCR4 expression, indicating low proliferative activity associated with poor migration to proliferation centers, with these features becoming increasingly marked during regression. Spontaneously regressed CLL displayed a transcriptome profile characterized by downregulation of metabolic processes as well as MYC and its downstream targets compared with nonregressing CLL. Moreover, spontaneous regression was associated with reversal of T-cell exhaustion features including reduced programmed cell death 1 expression and increased T-cell proliferation. Interestingly, archetypal CLL genomic aberrations including HIST1H1B and TP53 mutations and del(13q14) were found in some spontaneously regressing tumors, but genetic composition remained stable during regression. Conversely, a single case of CLL relapse following spontaneous regression was associated with increased BCR signaling, CLL proliferation, and clonal evolution. These observations indicate that spontaneously regressing CLL appear to undergo a period of proliferation before entering a more quiescent state, and that a complex interaction between genomic alterations and the microenvironment determines disease course. Together, the findings provide novel insight into the biological processes underpinning spontaneous CLL regression, with implications for CLL treatment.

The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus-dominated mixed culture

A methanotrophic community was enriched in a semi-continuous reactor under non-aseptic conditions with methane and ammonia as carbon and nitrogen source. After a year of operation, Methylosinus sp., accounted for 80% relative abundance of the total sequences identified from potential polyhydroxyalkanoates (PHAs) producers, dominated the methane-fed enrichment. Prior to induction of PHA accumulation, cells harvested from the parent reactor contained low level of PHA at 4.0 ± 0.3 wt%. The cells were later incubated in the absence of ammonia with various combinations of methane, propionic acid, and valeric acid to induce biosynthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Previous studies reported that methanotrophic utilization of odd-chain fatty acids for the production of PHAs requires reducing power from methane oxidation. However, our findings demonstrated that the PHB-containing methanotrophic enrichment does not require methane availability to generate 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV)—when odd-chain fatty acids are presented. The enrichment yielded up to 14 wt% PHA with various mole fractions of 3HV monomer depending on the availability of methane and odd-fatty acids. Overall, the addition of valeric acid resulted in a higher PHA content and a higher 3HV fraction. The highest 3HV fraction (up to 65 mol%) was obtained from the methane–valeric acid experiment, which is higher than those previously reported for PHA-producing methanotrophic mixed microbial cultures.

Thermophilic production of poly(3-hydroxybutyrate-co-3-hydrovalerate) by a mixed methane-utilizing culture

The production of polyhydroxyalkanoates (PHAs) from methane is limited to mesophiles and thus suffers from high energy requirements for cooling. To address this issue, the use of thermophilic processes is gaining interest, as this strategy may deliver improved economic feasibility for PHA production. This study reports the first thermophilic PHA-producing culture grown on methane at 55 °C in fill-and-draw batch reactors. Harvested cells were incubated with various combinations of methane, propionic acid and valeric acid to assess their capacity for the synthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Only PHB was produced when fed with methane alone. The addition of odd-carbon-number fatty acids resulted in higher PHA content with 3 HV fractions in the range of 15-99 mol%, depending on the types of fatty acids added. Acetic acid addition enhanced the synthesis of 3HB monomer, but not of 3 HV. On increasing the temperature to 58 °C, PHA productivity was not significantly affected.

Attenuated cortisol reactivity to psychosocial stress is associated with greater visual dependency in postural control

Despite known anatomical links between the hypothalamic-pituitary-adrenal (HPA) axis and the vestibular system, there are no studies on the relationship between postural control and HPA axis function. Visual dependence in postural control, often measured by increased postural sway on exposure to visual motion, is an indication of altered visual-vestibular integration with greater weighting towards visual cues for balance. Visual dependence is more common in older age and a range of vestibular and non-vestibular health conditions. The relationship between visual dependence in postural control was investigated in relation to cortisol reactivity to psychosocial stress (using the Trier Social Stress Test for groups: TSST-G), as an index of HPA axis function, in healthy young females. In those who exhibited a cortisol response (>2 nmol/l), a negative relationship between stress-induced cortisol reactivity and visual dependence in postural control was observed, since those with the largest cortisol response showed less visual motion induced postural sway (measured by force platform). This finding in healthy females indicates that subtle non-clinical differences in vestibular function are associated with dysregulated HPA axis activity as indicated by lower cortisol reactivity to psychosocial stress. It adds to the growing body of evidence linking blunted cortisol reactivity to stress to poor homeostatic regulation and potential negative health and behavioural outcomes.