Synthesis of an Antimicrobial Enterobactin-Muraymycin Conjugate for Improved Activity Against Gram-Negative Bacteria

Overcoming increasing antibiotic resistance requires the development of novel antibacterial agents that address new targets in bacterial cells. Naturally occurring nucleoside antibiotics (such as muraymycins) inhibit the bacterial membrane protein MraY, a clinically unexploited essential enzyme in peptidoglycan (cell wall) biosynthesis. Even though a range of synthetic muraymycin analogues has already been reported, they generally suffer from limited cellular uptake and a lack of activity against Gram-negative bacteria. We herein report an approach to overcome these hurdles: a synthetic muraymycin analogue has been conjugated to a siderophore, i. e. the enterobactin derivative EntKL, to increase the cellular uptake into Gram-negative bacteria. The resultant conjugate showed significantly improved antibacterial activity against an efflux-deficient E. coli strain, thus providing a proof-ofconcept of this novel approach and a starting point for the future optimisation of such conjugates towards potent agents against Gram-negative pathogens

Imaging the Renner-Teller effect using laser-induced electron diffraction

Structural information on electronically excited neutral molecules can be indirectly retrieved, largely through pump-probe and rotational spectroscopy measurements with the aid of calculations. Here, we demonstrate the direct structural retrieval of neutral carbonyl disulfide (CS$_2$) in the B$^1$B$_2$ excited electronic state using laser-induced electron diffraction (LIED). We unambiguously identify the ultrafast symmetric stretching and bending of the field-dressed neutral CS$_2$ molecule with combined picometer and attosecond resolution using intrapulse pump-probe excitation and measurement. We invoke the Renner-Teller effect to populate the B$^1$B$_2$ excited state in neutral CS$_2$, leading to bending and stretching of the molecule. Our results demonstrate the sensitivity of LIED in retrieving the geometric structure of CS$_2$, which is known to appear as a two-center scatterer

Systolic blood pressure reduction during the first 24 h in acute heart failure admission: friend or foe?

Aims: Changes in systolic blood pressure (SBP) during an admission for acute heart failure (AHF), especially those leading to hypotension, have been suggested to increase the risk for adverse outcomes. Methods and results: We analysed associations of SBP decrease during the first 24 h from randomization with serum creatinine changes at the last time-point available (72 h), using linear regression, and with 30- and 180-day outcomes, using Cox regression, in 1257 patients in the VERITAS study. After multivariable adjustment for baseline SBP, greater SBP decrease at 24 h from randomization was associated with greater creatinine increase at 72 h and greater risk for 30-day all-cause death, worsening heart failure (HF) or HF readmission. The hazard ratio (HR) for each 1 mmHg decrease in SBP at 24 h for 30-day death, worsening HF or HF rehospitalization was 1.01 [95% confidence interval (CI) 1.00–1.02; P = 0.021]. Similarly, the HR for each 1 mmHg decrease in SBP at 24 h for 180-day all-cause mortality was 1.01 (95% CI 1.00–1.03; P = 0.038). The associations between SBP decrease and outcomes did not differ by tezosentan treatment group, although tezosentan treatment was associated with a greater SBP decrease at 24 h. Conclusions: In the current post hoc analysis, SBP decrease during the first 24 h was associated with increased renal impairment and adverse outcomes at 30 and 180 days. Caution, with special attention to blood pressure monitoring, should be exercised when vasodilating agents are given to AHF patients

Predictors and associations with outcomes of length of hospital stay in patients with acute heart failure: results from VERITAS

Background: The length of hospital stay (LOS) is important in patients admitted for acute heart failure (AHF) because it prolongs an unpleasant experience for the patients and adds substantially to health care costs. Methods and Results: We examined the association between LOS and baseline characteristics, 10-day post-discharge HF readmission, and 90-day post-discharge mortality in 1347 patients with AHF enrolled in the VERITAS program. Longer LOS was associated with greater HF severity and disease burden at baseline; however, most of the variability of LOS could not be explained by these factors. LOS was associated with a higher HF risk of both HF readmission (odds ratio for 1-day increase: 1.08; 95% confidence interval [CI] 1.01–1.16; P = .019) and 90-day mortality (hazard ratio for 1-day increase: 1.05; 95% CI 1.02–1.07; P < .001), although these associations are partially explained by concurrent end-organ damage and worsening heart failure during the first days of admission. Conclusions: In patients who have been admitted for AHF, longer length of hospital stay is associated with a higher rate of short-term mortality. Clinical Trial Registration: VERITAS-1 and -2: Clinicaltrials.gov identifiers NCT00525707 and NCT00524433

HDR Brachytherapy and SBRT as Bridging Therapy to Liver Transplantation in HCC Patients: A Single-Center Experience

Background: In the treatment of patients with HCC awaiting liver transplantation (LT), local ablative treatments (LAT) are available either for downstaging or as bridging treatment. We present our clinical experience with both available radiation-based techniques, brachytherapy (BT), and stereotactic body radiotherapy (SBRT). Methods: All patients diagnosed with HCC and who were treated with BT or SBRT at our institution between 2011 and 2018 were retrospectively reviewed. The current analysis included all patients who subsequently underwent LT. Results: A total of 14 patients (male=9; female=5) were evaluated. Seven underwent BT for bridging before LT, and seven were treated with SBRT. BT was performed with a prescribed dose of 1 × 15 Gy, while SBRT was applied with 37 Gy (65%-iso) in three fractions in six patients, and one patient was treated with 54 Gy (100%-iso) in nine fractions. The treatment was generally well tolerated. One case of grade 3 bleeding was reported after BT, and one case of liver failure occurred following SBRT. All patients underwent LT after a median time interval of 152 days (range 47–311) after BT and 202 days (range 44–775) following SBRT. In eight cases, no viable tumor was found in the explanted liver, while four liver specimens showed vital tumor. The median follow-up after SBRT was 41 months and 17 months following BT. Overall, no hepatic HCC recurrence occurred following LT. Conclusion: Both SBRT and BT are feasible and well tolerated as bridging to LT when applied with caution in patients with impaired liver function. Radiation-based treatments can close the gap for patients not suitable for other locally ablative treatment options

Molecular rationale for antibody-mediated targeting of the hantavirus fusion glycoprotein

Rissanen, Ilona Stass, Robert Krumm, Stefanie A Seow, Jeffrey Hulswit, Ruben Jg Paesen, Guido C Hepojoki, Jussi Vapalahti, Olli Lundkvist, Ake Reynard, Olivier Volchkov, Viktor Doores, Katie J Huiskonen, Juha T Bowden, Thomas A eng MR/L009528/1/Medical Research Council/United Kingdom MR/S007555/1/Medical Research Council/United Kingdom MR/N002091/1/Medical Research Council/United Kingdom MR/K024426/1/Medical Research Council/United Kingdom 309605/Academy of Finland 649053/H2020 European Research Council 203141/Z/16Z/Wellcome Trust/United Kingdom 060208/Z/00/Z/Wellcome Trust/United Kingdom 093305/Z/10/Z/Wellcome Trust/United Kingdom England Elife. 2020 Dec 22;9. pii: 58242. doi: 10.7554/eLife.58242.The intricate lattice of Gn and Gc glycoprotein spike complexes on the hantavirus envelope facilitates host-cell entry and is the primary target of the neutralizing antibody-mediated immune response. Through study of a neutralizing monoclonal antibody termed mAb P-4G2, which neutralizes the zoonotic pathogen Puumala virus (PUUV), we provide a molecular-level basis for antibody-mediated targeting of the hantaviral glycoprotein lattice. Crystallographic analysis demonstrates that P-4G2 binds to a multi-domain site on PUUV Gc and may preclude fusogenic rearrangements of the glycoprotein that are required for host-cell entry. Furthermore, cryo-electron microscopy of PUUV-like particles in the presence of P-4G2 reveals a lattice-independent configuration of the Gc, demonstrating that P-4G2 perturbs the (Gn-Gc)4 lattice. This work provides a structure-based blueprint for rationalizing antibody-mediated targeting of hantaviruses.Peer reviewe

Exotic foods reveal contact between South Asia and the Near East during the second millennium BCE

Aunque el papel clave del comercio a larga distancia en la transformación de las cocinas en todo el mundo está bien documentado desde al menos la época romana, la prehistoria del comercio de alimentos euroasiático es menos visible. Con el fin de arrojar luz sobre la transformación de las cocinas del Mediterráneo oriental durante la Edad del Bronce y la Edad del Hierro Temprana, analizamos los microrestos y las proteínas conservadas en el cálculo dental de individuos que vivieron durante el segundo milenio a. Nuestros resultados proporcionan evidencia clara del consumo de alimentos básicos esperados, como cereales (Triticeae), sésamo ( Sesamum ) y dátiles ( Phoenix ). Además, informamos evidencia del consumo de soja ( glicina ), probable banano ( Musa ) y cúrcuma (Curcuma ), que hace retroceder la evidencia más antigua de estos alimentos en el Mediterráneo por siglos (cúrcuma) o incluso milenios (soja). Descubrimos que, desde principios del segundo milenio en adelante, al menos algunas personas en el Mediterráneo oriental tuvieron acceso a alimentos de lugares distantes, incluido el sur de Asia, y esos productos probablemente se consumieron en forma de aceites, frutos secos y especias. Estos conocimientos nos obligan a repensar la complejidad y la intensidad del comercio indo-mediterráneo durante la Edad del Bronce, así como el grado de globalización en la cocina del Mediterráneo oriental temprano. Although the key role of long-distance trade in the transformation of cuisines worldwide has been well-documented since at least the Roman era, the prehistory of the Eurasian food trade is less visible. In order to shed light on the transformation of Eastern Mediterranean cuisines during the Bronze Age and Early Iron Age, we analyzed microremains and proteins preserved in the dental calculus of individuals who lived during the second millennium BCE in the Southern Levant. Our results provide clear evidence for the consumption of expected staple foods, such as cereals (Triticeae), sesame (Sesamum), and dates (Phoenix). We additionally report evidence for the consumption of soybean (Glycine), probable banana (Musa), and turmeric (Curcuma), which pushes back the earliest evidence of these foods in the Mediterranean by centuries (turmeric) or even millennia (soybean). We find that, from the early second millennium onwards, at least some people in the Eastern Mediterranean had access to food from distant locations, including South Asia, and such goods were likely consumed as oils, dried fruits, and spices. These insights force us to rethink the complexity and intensity of Indo-Mediterranean trade during the Bronze Age as well as the degree of globalization in early Eastern Mediterranean cuisine

Cytosine-5 RNA methylation links protein synthesis to cell metabolism.

Posttranscriptional modifications in transfer RNA (tRNA) are often critical for normal development because they adapt protein synthesis rates to a dynamically changing microenvironment. However, the precise cellular mechanisms linking the extrinsic stimulus to the intrinsic RNA modification pathways remain largely unclear. Here, we identified the cytosine-5 RNA methyltransferase NSUN2 as a sensor for external stress stimuli. Exposure to oxidative stress efficiently repressed NSUN2, causing a reduction of methylation at specific tRNA sites. Using metabolic profiling, we showed that loss of tRNA methylation captured cells in a distinct catabolic state. Mechanistically, loss of NSUN2 altered the biogenesis of tRNA-derived noncoding fragments (tRFs) in response to stress, leading to impaired regulation of protein synthesis. The intracellular accumulation of a specific subset of tRFs correlated with the dynamic repression of global protein synthesis. Finally, NSUN2-driven RNA methylation was functionally required to adapt cell cycle progression to the early stress response. In summary, we revealed that changes in tRNA methylation profiles were sufficient to specify cellular metabolic states and efficiently adapt protein synthesis rates to cell stress.This work was funded by a Cancer Research UK Senior Fellowship (C10701/A15181), the European Research Council (ERC; 310360), and the Medical Research Council UK (MR/M01939X/1). Part of this work was carried out in the framework of the European COST action EPITRAN 16120. SK receives funding from the DFG (KE1943/3-1). The funders had no role in study design, data collection, and analysis, decision to publish, 5 or preparation of the manuscript