Space-climatic feedback of the magnetic solar cycle through the interplanetary space.

The relationship between solar magnetic activity and solar wind parameters, with observed time-delayed mutual coupling, is an outstanding challenge in space physics. In this study, drawing inspiration from recent observations, we propose a reconciliation framework whose fundamentals stand in the Parker model for solar wind expansion. We investigate the effects on fluctuations in solar wind speed when linearly sustained by an oscillating magnetic solar dynamo described via a modified Van der Pol nonlinear oscillator mimicking the magnetic activity at different timescales. Our findings reveal the presence of a "space-climatic feedback" that, in absence of the driving magnetic activity, slows down solar wind velocity fluctuations. The combined action of the slowing down of fluctuations and a periodic driving is the responsible for the time-delay between solar magnetic activity and solar wind dynamics. Furthermore, we also demonstrate how the space-climatic feedback controls the value of the time-delay which depends on the different periodicities of the driving magnetic activity. This holistic approach provides a formal link at the interplay between solar magnetic activity and solar wind dynamics through the interplanetary space which can advance our understanding of long-term effects of solar activity on solar wind variations, and consequently on interactions with planetary environments.

The crystal structure of methanogen McrD, a methyl-coenzyme M reductase-associated protein.

Methyl-coenzyme M reductase (MCR) is a multi-subunit (α2ß2γ2) enzyme responsible for methane formation via its unique F430 cofactor. The genes responsible for producing MCR (mcrA, mcrB and mcrG) are typically colocated with two other highly conserved genes mcrC and mcrD. We present here the high-resolution crystal structure for McrD from a human gut methanogen Methanomassiliicoccus luminyensis strain B10. The structure reveals that McrD comprises a ferredoxin-like domain assembled into an α + ß barrel-like dimer with conformational flexibility exhibited by a functional loop. The description of the M. luminyensis McrD crystal structure contributes to our understanding of this key conserved methanogen protein typically responsible for promoting MCR activity and the production of methane, a greenhouse gas.

A novel mutation in IAA16 is associated with dicamba resistance in Chenopodium album.

BACKGROUND: Resistance to dicamba in Chenopodium album was first documented over a decade ago, however, the molecular basis of dicamba resistance in this species has not been elucidated. In this research, the resistance mechanism in a dicamba-resistant C. album phenotype was investigated using a transcriptomics (RNA-sequence) approach. RESULTS: The dose-response assay showed that the resistant (R) phenotype was nearly 25-fold more resistant to dicamba than a susceptible (S) phenotype of C. album. Also, dicamba treatment significantly induced transcription of the known auxin-responsive genes, Gretchen Hagen 3 (GH3), small auxin-up RNAs (SAURs), and 1-aminocyclopropane-1-carboxylate synthase (ACS) genes in the susceptible phenotype. Comparing the transcripts of auxin TIR/AFB receptors and auxin/indole-3-acetic acid (AUX/IAA) proteins identified from C. album transcriptomic analysis revealed that the R phenotype contained a novel mutation at the first codon of the GWPPV degron motif of IAA16, resulting in an amino acid substitution of glycine (G) with aspartic acid (D). Sequencing the IAA16 gene in other R and S individuals further confirmed that all the R individuals contained the mutation. CONCLUSION: In this research, we describe the dicamba resistance mechanism in the only case of dicamba-resistant C. album reported to date. Prior work has shown that the dicamba resistance allele confers significant growth defects to the R phenotype investigated here, suggesting that dicamba-resistant C. album carrying this novel mutation in the IAA16 gene may not persist at high frequencies upon removal of dicamba application. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

High-level nitrofurantoin resistance in a clinical isolate of Klebsiella pneumoniae: a comparative genomics and metabolomics analysis.

Nitrofurantoin is a commonly used chemotherapeutic agent in the treatment of uncomplicated urinary tract infections caused by the problematic multidrug resistant Gram-negative pathogen Klebsiella pneumoniae. The present study aims to elucidate the mechanism of nitrofurantoin action and high-level resistance in K. pneumoniae using whole-genome sequencing (WGS), qPCR analysis, mutation structural modeling and untargeted metabolomic analysis. WGS profiling of evolved highly resistant mutants (nitrofurantoin minimum inhibitory concentrations > 256 mg/L) revealed modified expression of several genes related to membrane transport (porin ompK36 and efflux pump regulator oqxR) and nitroreductase activity (ribC and nfsB, involved in nitrofurantoin reduction). Untargeted metabolomics analysis of total metabolites extracted at 1 and 4 h post-nitrofurantoin treatment revealed that exposure to the drug caused a delayed effect on the metabolome which was most pronounced after 4 h. Pathway enrichment analysis illustrated that several complex interrelated metabolic pathways related to nitrofurantoin bacterial killing (aminoacyl-tRNA biosynthesis, purine metabolism, central carbohydrate metabolism, and pantothenate and CoA biosynthesis) and the development of nitrofurantoin resistance (riboflavin metabolism) were significantly perturbed. This study highlights for the first time the key role of efflux pump regulator oqxR in nitrofurantoin resistance and reveals global metabolome perturbations in response to nitrofurantoin, in K. pneumoniae.IMPORTANCEA quest for novel antibiotics and revitalizing older ones (such as nitrofurantoin) for treatment of difficult-to-treat Gram-negative bacterial infections has become increasingly popular. The precise antibacterial activity of nitrofurantoin is still not fully understood. Furthermore, although the prevalence of nitrofurantoin resistance remains low currently, the drug's fast-growing consumption worldwide highlights the need to comprehend the emerging resistance mechanisms. Here, we used multidisciplinary techniques to discern the exact mechanism of nitrofurantoin action and high-level resistance in Klebsiella pneumoniae, a common cause of urinary tract infections for which nitrofurantoin is the recommended treatment. We found that the expression of multiple genes related to membrane transport (including active efflux and passive diffusion of drug molecules) and nitroreductase activity was modified in nitrofurantoin-resistant strains, including oqxR, the transcriptional regulator of the oqxAB efflux pump. Furthermore, complex interconnected metabolic pathways that potentially govern the nitrofurantoin-killing mechanisms (e.g., aminoacyl-tRNA biosynthesis) and nitrofurantoin resistance (riboflavin metabolism) were significantly inhibited following nitrofurantoin treatment. Our study could help inform the improvement of nitrofuran derivatives, the development of new pharmacophores, or drug combinations to support the resurgence of nitrofurantoin in the management of multidrug resistant K. pneumouniae infection.

Crystal Structures of Bacterial Pectin Methylesterases Pme8A and PmeC2 from Rumen Butyrivibrio.

Pectin is a complex polysaccharide that forms a substantial proportion of the plant's middle lamella of forage ingested by grazing ruminants. Methanol in the rumen is derived mainly from methoxy groups released from pectin by the action of pectin methylesterase (PME) and is subsequently used by rumen methylotrophic methanogens that reduce methanol to produce methane (CH4). Members of the genus Butyrivibrio are key pectin-degrading rumen bacteria that contribute to methanol formation and have important roles in fibre breakdown, protein digestion, and the biohydrogenation of fatty acids. Therefore, methanol release from pectin degradation in the rumen is a potential target for CH4 mitigation technologies. Here, we present the crystal structures of PMEs belonging to the carbohydrate esterase family 8 (CE8) from Butyrivibrio proteoclasticus and Butyrivibrio fibrisolvens, determined to a resolution of 2.30 Å. These enzymes, like other PMEs, are right-handed ß-helical proteins with a well-defined catalytic site and reaction mechanisms previously defined in insect, plant, and other bacterial pectin methylesterases. Potential substrate binding domains are also defined for the enzymes.

Intermittent Normal Ventricular Conduction in Left Bundle Branch Block After TAVR.

In a patient who previously developed left bundle branch block after transcatheter aortic valve replacement, intermittent narrow QRS complexes were recorded on ambulatory electrocardiography monitoring. The peculiar distribution of wide and narrow QRS complexes suggested the presence of a window of supernormality in the refractory period of a branch block that on other occasions exhibited the Wenckebach phenomenon. (Level of Difficulty: Intermediate.).

Multi-Omic Profiling, Structural Characterization, and Potent Inhibitor Screening of Evasion-Related Proteins of a Parasitic Nematode, Haemonchus contortus, Surviving Vaccine Treatment.

The emergence of drug-resistant parasitic nematodes in both humans and livestock calls for development of alternative and cost-effective control strategies. Barbervax® is the only registered vaccine for the economically important ruminant strongylid Haemonchus contortus. In this study, we compared the microbiome, genome-wide diversity, and transcriptome of H. contortus adult male populations that survived vaccination with an experimental vaccine after inoculation in sheep. Our genome-wide SNP analysis revealed 16 putative candidate vaccine evasion genes. However, we did not identify any evidence for changes in microbial community profiling based on the 16S rRNA gene sequencing results of the vaccine-surviving parasite populations. A total of fifty-eight genes were identified as significantly differentially expressed, with six genes being long non-coding (lnc) RNAs and none being putative candidate SNP-associated genes. The genes that highly upregulated in surviving parasites from vaccinated animals were associated with GO terms belonging to predominantly molecular functions and a few biological processes that may have facilitated evasion or potentially lessened the effect of the vaccine. These included five targets: astacin (ASTL), carbonate dehydratase (CA2), phospholipase A2 (PLA2), glutamine synthetase (GLUL), and fatty acid-binding protein (FABP3). Our tertiary structure predictions and modelling analyses were used to perform in silico searches of all published and commercially available inhibitor molecules or substrate analogs with potential broad-spectrum efficacy against nematodes of human and veterinary importance.

Alert-LDL-2: adherence to guidelines and goals attainment in the treatment of diabetic patients with dyslipidemia.

BACKGROUND: Type 2 diabetes mellitus is associated with a cluster of lipid and apolipoprotein abnormalities which increase the risk for atherosclerotic cardiovascular disease. The aim of this study was to evaluate the adherence to guidelines-oriented dyslipidemia treatment in diabetic patients and to assess the efficacy of a territorial goal-oriented program. METHODS: One thousand seventy-one diabetic patients at very high cardiovascular risk were enrolled in this prospective study. They performed a clinical-laboratory follow-up program, received lifestyle recommendations and optimization of their antihyperlipidemic therapies. At the beginning and the 3-month follow-up visit, LDL-c data were collected, and further therapies were prescribed to the patients that did not reach the target. After 12 month follow-up, LDL-c data were collected again. RESULTS: Diabetic patients significantly improved mean LDL cholesterol levels during one-year follow-up (LDLc mean value 135 mg/dL at baseline, 60 mg/dL at the end of the study), obtaining a greater reduction compared to non-diabetic patients participating in the same program. Accordingly, the percentage of patients that reached the lipid target was significantly higher in diabetic patients after 3-months and 12- follow-ups (P<0.05). Diabetic patients assuming statins, both in monotherapy and in combination with ezetimibe, increased during the follow-up (74.1% at the enrolment vs. 88.2% one year later). GLP1ra-treated patients achieved the greatest reduction in cholesterol levels compared to baseline. CONCLUSIONS: The results of the study recommend encouraging strategies and appropriate treatments to achieve a targeted lipid profile in diabetic patients at very high cardiovascular risk.

Accelerating Digitalization in Healthcare with the InSilicoTrials Cloud-Based Platform: Four Use Cases.

The use of in silico trials is expected to play an increasingly important role in the development and regulatory evaluation of new medical products. Among the advantages that in silico approaches offer, is that they permit testing of drug candidates and new medical devices using virtual patients or computational emulations of preclinical experiments, allowing to refine, reduce or even replace time-consuming and costly benchtop/in vitro/ex vivo experiments as well as the involvement of animals and humans in in vivo studies. To facilitate and widen the adoption of in silico trials, InSilicoTrials Technologies has developed a cloud-based platform, hosting healthcare simulation tools for different bench, preclinical and clinical evaluations, and for diverse disease areas. This paper discusses four use cases of in silico trials performed using the InSilicoTrials.com platform. The first application illustrates how in silico approaches can improve the early preclinical assessment of drug-induced cardiotoxicity risks. The second use case is a virtual reproduction of a bench test for the safety assessment of transcatheter heart valve substitutes. The third and fourth use cases are examples of virtual patients generation to evaluate treatment effects in multiple sclerosis and prostate cancer patients, respectively.

Structural characterisation of methanogen pseudomurein cell wall peptide ligases homologous to bacterial MurE/F murein peptide ligases.

Archaea have diverse cell wall types, yet none are identical to bacterial peptidoglycan (murein). Methanogens Methanobacteria and Methanopyrus possess cell walls of pseudomurein, a structural analogue of murein. Pseudomurein differs from murein in containing the unique archaeal sugar N-acetyltalosaminuronic acid instead of N-acetylmuramic acid, ß-1,3 glycosidic bonds in place of ß-1,4 bonds and only l-amino acids in the peptide cross-links. We have determined crystal structures of methanogen pseudomurein peptide ligases (termed pMurE) from Methanothermus fervidus (Mfer762) and Methanothermobacter thermautotrophicus (Mth734) that are structurally most closely related to bacterial MurE peptide ligases. The homology of the archaeal pMurE and bacterial MurE enzymes is clear both in the overall structure and at the level of each of the three domains. In addition, we identified two UDP-binding sites in Mfer762 pMurE, one at the exterior surface of the interface of the N-terminal and middle domains, and a second site at an inner surface continuous with the highly conserved interface of the three domains. Residues involved in ATP binding in MurE are conserved in pMurE, suggesting that a similar ATP-binding pocket is present at the interface of the middle and the C-terminal domains of pMurE. The presence of pMurE ligases in members of the Methanobacteriales and Methanopyrales, that are structurally related to bacterial MurE ligases, supports the idea that the biosynthetic origins of archaeal pseudomurein and bacterial peptidoglycan cell walls are evolutionarily related.

The modulation of acute stress on model-free and model-based reinforcement learning in gambling disorder.

Background and aims: Experiencing acute stress is common in behavioral addictions such as gambling disorder. Additionally, like most substance-induced addictions, aberrant decision-making wherein a reactive habit-induced response (conceptualized as a Model-free [MF] in reinforcement learning) suppresses a flexible goal-directed response (conceptualized as a Model-based [MB]) is also common in gambling disorder. In the current study we investigated the influence of acute stress on the balance between habitual response and the goal-directed system. Methods: A sample of N = 116 problem gamblers (PG) and healthy controls (HC) performed an acute stress task - the Socially Evaluated Cold pressure task (SECPT) - or a control task. Self-reported stress and salivary cortisol were collected as measures of acute stress. Following the SECPT, participants performed the Two-Step Markov Task to account for the relative contribution of MB and MF strategies. Additionally, verbal working memory and IQ measures were collected to account for their mediating effects on the orchestration between MB/MF and the impact of stress. Results: Both groups had comparable baseline and stress-induced cortisol response to the SECPT. Non-stressed PG displayed lower MB learning than HC. MANOVA and regression analyses showed a deleterious effect of stress-induced cortisol response on the orchestration between MB and MF learning in HC but not in PG. These effects remained when controlling for working memory and IQ. Discussion and Conclusions: We found an abnormal pattern of modulation of stress on the orchestration between MB and MF learning among PG. Several interpretations and future research directions are discussed.

Supraventricular Tachycardia Following Mitral Valve Surgery.

A man in his mid-50s with a history of mitral valve repair presented to the emergency department with complaints of recent-onset palpitation. The QRS complexes displayed pairs of beats exhibiting complete right bundle branch block and QRS duration of 140 milliseconds followed by a third beat with normal configuration and QRS duration of 70 milliseconds. What would you do next?

Mapping immunogenic epitopes of an adhesin-like protein from Methanobrevibacter ruminantium M1 and comparison of empirical data with in silico prediction methods.

In silico prediction of epitopes is a potentially time-saving alternative to experimental epitope identification but is often subject to misidentification of epitopes and may not be useful for proteins from archaeal microorganisms. In this study, we mapped B- and T-cell epitopes of a model antigen from the methanogen Methanobrevibacter ruminantium M1, the Big_1 domain (AdLP-D1, amino acids 19-198) of an adhesin-like protein. A series of 17 overlapping 20-mer peptides was selected to cover the Big_1 domain. Peptide-specific antibodies were produced in mice and measured by ELISA, while an in vitro splenocyte re-stimulation assay determined specific T-cell responses. Overall, five peptides of the 17 peptides were shown to be major immunogenic epitopes of AdLP-D1. These immunogenic regions were examined for their localization in a homology-based model of AdLP-D1. Validated epitopes were found in the outside region of the protein, with loop like secondary structures reflecting their flexibility. The empirical data were compared with epitope predictions made by programmes based on a range of algorithms. In general, the epitopes identified by in silico predictions were not comparable to those determined empirically.

Clinical outcomes of newly diagnosed, stable angina patients managed according to current guidelines. The ARCA (Arca Registry for Chronic Angina) Registry: A prospective, observational, nationwide study.

BACKGROUND: Clinical outcomes of stable angina patients treated according to guidelines recommendations (medical therapy first, selective revascularization in high risk or unresponsive patients) are not fully known. METHODS AND RESULTS: Eight hundred thirty-three patients with newly diagnosed, stable angina were enrolled in a prospective, observational, nationwide registry and followed for 1 year. Symptoms and quality of life were evaluated with the CCS angina grading, with a self-assessment scale and with the SAQ-7. A composite end-point of MACEs (all-cause death, non-fatal myocardial infarction, non-fatal stroke or hospitalization for unstable angina) at 1 year was considered. Upon enrollment, all patients were prescribed guidelines directed medical therapy. After one month of therapy, angina relieved or improved in 47% of the overall population. Patients in CCS class I significantly increased from 28.4% at enrollment to 67.1% at 12 months, and the SAQ-7 score from 58.4 ± 20 to 85.9 ± 14. The rate of MACEs was low (2.9%) in the overall population. After one month of medical therapy, 40.6% of patients were referred for coronary angiography and revascularization for resistant symptoms (invasive strategy). Among these, 38.2% had normal coronary arteries and 47% actually underwent revascularization. No difference between invasive and medical groups was found at 12 months in symptoms, quality of life and MACEs, except for a greater improvement in self-assessed symptoms in the invasive group. Combined medical and invasive strategies left 28.5% of patients still symptomatic at the end of the study. CONCLUSIONS: The study confirms the efficacy and safety of a tailored approach to stable angina, as recommended by guidelines, with medical therapy first followed by selective revascularization when needed.

ALERT-LDL: adherence to guidelines in the treatment of patients with dyslipidemia.

The association between LDL-c levels and cardiovascular outcomes suggests tailoring lipid-lowering therapies according to total cardiovascular risk. We aimed to evaluate the adherence to guidelines-oriented dyslipidaemia's treatment in an outpatient population referring to ARCA cardiologists, and assess the efficacy of treatment's optimization for each specific level of risk. Three thousand seventy-five patients enrolled in this prospective study were classified according to cardiovascular risk category, and their therapies were optimized. At the beginning and the 3 month follow-up visit, LDL-c data were collected, and further therapies were prescribed to the patients that did not reach the target. A significant LDL-c reduction was observed in all subgroups at different cardiovascular risk at the end of the study (p < 0.05). The number of patients assuming statins, both in monotherapy and in combination with ezetimibe, increased during the follow-up (63% at the enrollment vs 89% after 12 months). At the enrollment, only 1.4% of patients were treated with PCSK-9 inhibitors while after 12 months the percentage increased both in high (5.8%) and very high-risk (18.4%) patients. At the beginning of the study, only 698/3075 patients (22.7%) reached lipid targets. At the end of the study, carried out by the referring cardiologists in the pertaining healthcare districts and specifically aimed to control the lipid profile, the percentage of patients on target increased in all risk categories (68.5%). Our results suggest carefully implementing measures that encourage outpatients and their cardiologists to achieve the targeted lipid profile according to cardiovascular risk.

Molecular and evolutionary basis for survival, its failure, and virulence factors of the zoonotic nematode Anisakis pegreffii.

Parasitism is a highly successful life strategy and a driving force in genetic diversity that has evolved many times over. Accidental infections of non-targeted hosts represent an opportunity for lateral host switches and parasite niche expansion. However, if directed toward organisms that are phylogenetically distant from parasite's natural host, such as humans, it may present a dead-end environment where the parasite fails to mature or is even killed by host immunity. One example are nematodes of Anisakidae family, genus Anisakis, that through evolution have lost the ability to propagate in terrestrial hosts, but can survive for a limited time in humans causing anisakiasis. To scrutinize versatility of Anisakis to infect an evolutionary-distant host, we performed transcriptomic profiling of larvae successfully migrating through the rat, a representative model of accidental human infection and compared it to that of larvae infecting an evolutionary-familiar, paratenic host (fish). In a homeothermic accidental host Anisakis upregulated ribosome-related genes, cell division, cuticle constituents, oxidative phosphorylation, in an unsuccessful attempt to molt to the next stage. In contrast, in the paratenic poikilothermic host where metabolic pathways were moderately upregulated or silenced, larvae prepared for dormancy by triggering autophagy and longevity pathways. Identified differences and the modelling of handful of shared transcripts, provide the first insights into evolution of larval nematode virulence, warranting their further investigation as potential drug therapy targets.

A mathematical model of lithosphere-atmosphere coupling for seismic events.

Significant evidence of ionosphere disturbance in connection to intense seismic events have been detected since two decades. It is generally believed that the energy transfer can be due to Acoustic Gravity Waves (AGW) excited at ground level by the earthquakes. In spite of the statistical evidence of the detected perturbations, the coupling between lithosphere and atmosphere has not been so far properly explained by an accurate enough model. In this paper, for the first time, we show the result of an analytical-quantitative model that describes how the pressure and density disturbance is generated in the lower atmosphere by the ground motion associated to earthquakes. The direct comparison between observed and modelled vertical profiles of the atmospheric temperature shows the capability of the model to accurately reproduce, with an high statistical significance, the observed temperature fluctuations induced by strong earthquakes.

Wolff-Parkinson-White pattern on alternate beats: What is the mechanism?

The Holter electrocardiogram from an asymptomatic man shows intermittent preexcitation. At the lowest rates all the QRS complexes display a WPW pattern. As the rate increases, preexcitation fails to occur and all the QRS complexes become persistently narrow. With a further increase in sinus rate the WPW occurs on alternate beats and this alternation is maintained for a while. A careful analysis of the accessory pathway conduction in relation to sinus-cycle length and morphology of the prior beat strongly supports the supernormal conduction through the Kent bundle associated with linking as the key mechanism underlying the preexcitation on alternate beats.