Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex

Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and, consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis

Death of a 29-Year-Old Male from Undifferentiated Sepsis

Tumour necrosis factor alpha inhibitors, such as infliximab, and other biologic agents are associated with increased risk of opportunistic infection, including tuberculosis. Tuberculosis infections associated with infliximab tend to present atypically and can be difficult to diagnose, as they are more likely to manifest as extrapulmonary or disseminated disease. The authors report a case involving a 29-year-old male patient who died following 16 days of treatment for undifferentiated sepsis and who was found on autopsy to have widespread disseminated tuberculosis. Prior to the onset of illness, the patient had received infliximab for the treatment of Crohn’s disease. Following discussion of the case, the authors review the definition of adverse events, provide a root cause analysis of the cognitive errors and breakdowns in the health care system that contributed to the reported outcome, and identify opportunities to address these breakdowns and improve patient safety measures for future cases

Disruption of the β1L Isoform of GABP Reverses Glioblastoma Replicative Immortality in a TERT Promoter Mutation-Dependent Manner

TERT promoter mutations reactivate telomerase, allowing for indefinite telomere maintenance and enabling cellular immortalization. These mutations specifically recruit the multimeric ETS factor GABP, which can form two functionally independent transcription factor species: a dimer or a tetramer. We show that genetic disruption of GABPβ1L (β1L), a tetramer-forming isoform of GABP that is dispensable for normal development, results in TERT silencing in a TERT promoter mutation-dependent manner. Reducing TERT expression by disrupting β1L culminates in telomere loss and cell death exclusively in TERT promoter mutant cells. Orthotopic xenografting of β1L-reduced, TERT promoter mutant glioblastoma cells rendered lower tumor burden and longer overall survival in mice. These results highlight the critical role of GABPβ1L in enabling immortality in TERT promoter mutant glioblastoma.This work was supported by a generous gift from the Dabbiere family (J.F.C.), the Hana Jabsheh Research Initiative (J.F.C.), NIH grant NCI P50CA097257 (J.F.C. and J.A.D.), NCI P01CA118816-06 (J.F.C.), T32 GM008568 and T32 CA151022 (A.M.), and NCI R01CA163336 (J.S.S.), and the Sontag Foundation Distinguished Scientist Award (J.S.S.). C.F. is supported by a US NIH K99/R00 Pathway to Independence Award (K99GM118909) from the National Institute of General Medical Sciences. Additional support was provided by Fundação para a Ciência e Tecnologia SFRH/BD/88220/2012 (A.X.-M.) and IF/00601/2012 (B.M.C.). J.A.D. is an investigator of the Howard Hughes Medical Institute.info:eu-repo/semantics/publishedVersio

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Effectiveness of discovery learning using a mobile otoscopy simulator on knowledge acquisition and retention in medical students: a randomized controlled trial

Abstract Background Portable educational technologies, like simulators, afford students the opportunity to learn independently. A key question in education, is how to pair self-regulated learning (SRL) with direct instruction. A cloud-based portable otoscopy simulator was employed to compare two curricula involving SRL. Pre-clerkship medical students used a prototype smartphone application, a 3D ear attachment and an otoscope to complete either otoscopy curriculum. Methods Pre-clerkship medical students were recruited and randomized to two curriculum designs. The “Discovery then Instruction” group received the simulator one week before a traditional lecture, while the “Instruction then Discovery” group received it after the lecture. To assess participants’ ability to identify otoscopic pathology, we used a 100-item test at baseline, post-intervention and 2-week retention time points. Secondary outcomes included self-reported comfort, time spent using the device, and a survey on learning preferences. Results Thirty-four students completed the study. Analysis of knowledge acquisition and retention showed improvement in scores of both groups and no significant effects of group (F1,31 = 0.53, p = 0.47). An analysis of participants’ self-reported comfort showed a significant group x test interaction (F1,36 = 4.61, p = 0.04), where only the discovery then instruction group’s comfort improved significantly. Overall device usage was low, as the discovery then instruction group spent 21.47 ± 26.28 min, while the instruction then discovery group spent 13.84 ± 18.71 min. The discovery first group’s time spent with the simulator correlated moderately with their post-test score (r = 0.42, p = 0.07). After the intervention, most participants in both groups (63–68%) stated that they would prefer the instruction then discovery sequence. Conclusions Both curricular sequences led to improved knowledge scores with no statistically significant knowledge differences. When given minimal guidance, students engaged in discovery learning minimally. There is value in SRL in simulation education, and we plan to further improve our curricular design by considering learner behaviours identified in this study

Probing solvation and reactivity in ionized polycyclic aromatic hydrocarbon-water clusters with photoionization mass spectrometry and electronic structure calculations

Polycyclic aromatic hydrocarbons (PAHs) may comprise up to 20% of the carbon budget in our galaxy and most PAHs condense onto water-rich icy grain mantles. Benzene-water clusters have been invoked as model systems for studying the photo-processing of water ice mantles containing PAHs. However, there is a paucity of information on larger aromatics, where the extended pi cloud could affect photo-processing. In this study, tunable vacuum ultraviolet (VUV) photoionization of naphthalene-water clusters N-x(H2O)(y) (N denotes naphthalene) is performed using synchrotron radiation and analyzed by reflectron time-of-flight mass spectrometry. Naphthalene clusters up to x = 4 are generated as are naphthalene-water clusters up to y = 25. At low photon energy (<11 eV), the naphthalene moiety is ionized and there is no proton transfer from N+ to the water sub-cluster, which is very different from the benzene-water system. Protonated products, N[(H2O)(x)H](+) and OH radical addition product (NOH)[(H2O)(x)H](+) are generated above 11 eV, suggesting that water sub-clusters dominate the dynamics at high photon energies. Ab initio calculations are performed to decipher the experimental results. Energetics of the neutral structures N(H2O)(1-4) and their photoionized counterparts are calculated, including ionization on the N moiety as well as on the water sub-cluster. Energy decomposition analysis (EDA) is performed to understand trends in the binding between the naphthalene and the water sub-cluster in the ionized species

Death of a 29-Year-Old Male from Undifferentiated Sepsis

Tumour necrosis factor alpha inhibitors, such as infliximab, and other biologic agents are associated with increased risk of opportunistic infection, including tuberculosis. Tuberculosis infections associated with infliximab tend to present atypically and can be difficult to diagnose, as they are more likely to manifest as extrapulmonary or disseminated disease. The authors report a case involving a 29-year-old male patient who died following 16 days of treatment for undifferentiated sepsis and who was found on autopsy to have widespread disseminated tuberculosis. Prior to the onset of illness, the patient had received infliximab for the treatment of Crohn’s disease. Following discussion of the case, the authors review the definition of adverse events, provide a root cause analysis of the cognitive errors and breakdowns in the health care system that contributed to the reported outcome, and identify opportunities to address these breakdowns and improve patient safety measures for future cases

Death of a 29-Year-Old Male from Undifferentiated Sepsis

Tumour necrosis factor alpha inhibitors, such as infliximab, and other biologic agents are associated with increased risk of opportunistic infection, including tuberculosis. Tuberculosis infections associated with infliximab tend to present atypically and can be difficult to diagnose, as they are more likely to manifest as extrapulmonary or disseminated disease. The authors report a case involving a 29-year-old male patient who died following 16 days of treatment for undifferentiated sepsis and who was found on autopsy to have widespread disseminated tuberculosis. Prior to the onset of illness, the patient had received infliximab for the treatment of Crohn’s disease. Following discussion of the case, the authors review the definition of adverse events, provide a root cause analysis of the cognitive errors and breakdowns in the health care system that contributed to the reported outcome, and identify opportunities to address these breakdowns and improve patient safety measures for future cases.Peer Reviewe

Mapping pedestrian heat stress in current and future heatwaves in Cardiff, Newport, and Wrexham in Wales, UK

The paper describes a study that uses computer simulation to assess the extent of heat stress experienced by pedestrians in three Welsh cities during heatwaves, with a view to identifying implications for urban planning and design practice. The simulation model used localized radiant temperature, wind speed, air temperature, as well as the metabolic rate and clothing insulation of occupants. Simulated results were partially evaluated using field measurement data and from the Land Surface Temperature data obtained from Landsat satellite thermography. Results suggest that peak heat stress is expected to increase by 4.5 °C in Universal Thermal Climate Index equivalent temperature by 2080, especially for urban areas exposed to direct sunlight. The percentage of daytime hours without heat stress are expected to decrease significantly, from 30 to 80% in 2020 to 10–70% by 2080. The study suggests that mitigation measures are essential to reduce future heat stress in Welsh cities and towns; these include interventions such as green and blue infrastructure, choice of trees and artificial shading, choice of both artificial surface materials and vegetation cover, and street layout with proper orientation and aspect ratio. The results have significant implications for local authorities, town planning, and landscape practice