Despite the success of genomics in identifying new essential bacterial genes, there is a lack of sustainable leads in antibacterial drug discovery to address increasing multidrug resistance. Type IIA ...topoisomerases cleave and religate DNA to regulate DNA topology and are a major class of antibacterial and anticancer drug targets, yet there is no well developed structural basis for understanding drug action. Here we report the 2.1 A crystal structure of a potent, new class, broad-spectrum antibacterial agent in complex with Staphylococcus aureus DNA gyrase and DNA, showing a new mode of inhibition that circumvents fluoroquinolone resistance in this clinically important drug target. The inhibitor 'bridges' the DNA and a transient non-catalytic pocket on the two-fold axis at the GyrA dimer interface, and is close to the active sites and fluoroquinolone binding sites. In the inhibitor complex the active site seems poised to cleave the DNA, with a single metal ion observed between the TOPRIM (topoisomerase/primase) domain and the scissile phosphate. This work provides new insights into the mechanism of topoisomerase action and a platform for structure-based drug design of a new class of antibacterial agents against a clinically proven, but conformationally flexible, enzyme class.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The increased incidence and severity of Clostridium difficile infection (CDI) are thought to result partly from the emergence of the hypervirulent BI/NAP1/027 strain. Limited recent data are ...available on the prevalence of BI/NAP1/027 in the United States (US). The objective of this study was to assess the recent prevalence of BI/NAP1/027 within the US Veterans Health Administration (VHA).
Patients with CDI at any Veterans Affairs Medical Center found to routinely test for the presence of BI/NAP1/027 during the study period were included between 1 June 2011 and 30 June 2016 in this retrospective, observational, nationwide study.
In total, 7571 patients had 8224 positive C. difficile tests that had a corresponding BI/NAP1/027 test. Of those, there were 1810 (22.0%) presumptive positive for BI/NAP1/027. The overall prevalence of BI/NAP1/027 decreased from a high of 26.2% in 2013 to 16.9% in 2016. Statistically significant reductions in rates from 2012 to 2016 occurred in seven of nine US Census Bureau regions.
The prevalence of C. difficile with the BI/NAP1/027 strain was 22.0% across the VHA between 2012 and 2016. Further studies are needed to confirm these results and for continued monitoring of the trends in BI/NAP1/027 prevalence.
Cell-penetrating peptides (CPPs) are capable of transporting molecules to which they are tethered across cellular membranes. Unsurprisingly, CPPs have attracted attention for their potential drug ...delivery applications, but several technical hurdles remain to be overcome. Chief among them is the so-called 'endosomal escape problem,' i.e. the propensity of CPP-cargo molecules to be endocytosed but remain entrapped in endosomes rather than reaching the cytosol. Previously, a CPP fused to calmodulin that bound calmodulin binding site-containing cargos was shown to efficiently deliver cargos to the cytoplasm, effectively overcoming the endosomal escape problem. The CPP-adaptor, "TAT-CaM," evinces delivery at nM concentrations and more rapidly than we had previously been able to measure. To better understand the kinetics and mechanism of CPP-adaptor-mediated cargo delivery, a real-time cell penetrating assay was developed in which a flow chamber containing cultured cells was installed on the stage of a confocal microscope to allow for observation ab initio. Also examined in this study was an improved CPP-adaptor that utilizes naked mole rat (Heterocephalus glaber) calmodulin in place of human and results in superior internalization, likely due to its lesser net negative charge. Adaptor-cargo complexes were delivered into the flow chamber and fluorescence intensity in the midpoint of baby hamster kidney cells was measured as a function of time. Delivery of 400 nM cargo was observed within seven minutes and fluorescence continued to increase linearly as a function of time. Cargo-only control experiments showed that the minimal uptake which occurred independently of the CPP-adaptor resulted in punctate localization consistent with endosomal entrapment. A distance analysis was performed for cell-penetration experiments in which CPP-adaptor-delivered cargo showing wider dispersions throughout cells as compared to an analogous covalently-bound CPP-cargo. Small molecule endocytosis inhibitors did not have significant effects upon delivery. The real-time assay is an improvement upon static endpoint assays and should be informative in a broad array of applications.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Clinical trials of ACEi-induced angioedema have tried to replicate the success of treatments for hereditary angioedema (HAE) based on the widely accepted shared pathophysiology of bradykinin ...accumulation 2. Given the acute nature of angioedema, inclusion of an emergency medicine-trained physician would have benefitted the development of their study design. In this study, C1-INH was dosed at 20 international units per kilogram (IU/kg), rounded up to the next 500 IU vial.
Social associations within mixed-species bird flocks can promote information flow about food availability and provide predator avoidance benefits. The relationship between flocking propensity, ...foraging habitat quality, and interspecific competition can be altered by human-induced habitat degradation. Here we take a close look at sociality within two ecologically important flock-leader (core) species, the Carolina chickadee (Poecile carolinensis) and tufted titmouse (Baeolophus bicolor), to better understand how degradation of foraging habitat quality affects mixed-species flocking dynamics. We compared interactions of free ranging wild birds across a gradient of foraging habitat quality in three managed forest remnants. Specifically, we examined aspects of the social network at each site, including network density, modularity, and species assortativity. Differences in the social networks between each end of our habitat gradient suggest that elevated levels of interspecific association are more valuable in the habitat with low quality foraging conditions. This conclusion is supported by two additional findings: First, foraging height for the subordinate Carolina chickadee relative to the tufted titmouse decreased with an increase in the number of satellite species in the most disturbed site but not in the other two sites. Second, the chickadee gargle call rate, an acoustic signal emitted during agonistic encounters between conspecifics, was relatively higher at the high-quality site. Collectively, these results suggest an increase in heterospecific associations increases the value of cross-species information flow in degraded habitats.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
For 7 years, the Kidney Transplantation Committee of the United Network for Organ Sharing/Organ Procurement Transplantation Network has attempted to revise the kidney allocation algorithm for adults ...(≥18 years) in end‐stage renal disease awaiting deceased donor kidney transplants. Changes to the kidney allocation system must conform to the 1984 National Organ Transplant Act (NOTA) which clearly states that allocation must take into account both efficiency (graft and person survival) and equity (fair distribution). In this article, we evaluate three allocation models: the current system, age‐matching and a two‐step model that we call “Equal Opportunity Supplemented by Fair Innings (EOFI)”. We discuss the different conceptions of efficiency and equity employed by each model and evaluate whether EOFI could actually achieve the NOTA criteria of balancing equity and efficiency given current conditions of growing scarcity and donor‐candidate age mismatch.
The authors develop a multiprinciple approach to ethically justify allocation of younger deceased donor kidneys to younger adult recipients meeting the National Organ Transplant Act criteria of balancing equity and efficiency. See editorial by Gill on page 1973.
Emergency departments (EDs) often serve vulnerable populations who may lack primary care and have suffered disproportionate COVID-19 pandemic effects. Comparing patients having and lacking a regular ...source of medical care and other ED patient characteristics, we assessed COVID-19 vaccine hesitancy, reasons for not wanting the vaccine, perceived access to vaccine sites and willingness to get the vaccine as part of ED care.
Cross sectional survey conducted from 12/10/2020 to 3/7/21 at 15 safety net United States EDs. Primary outcomes were COVID-19 vaccine hesitancy, reasons for vaccine hesitancy, and sites (including EDs) for potential COVID-19 vaccine receipt.
Of 2575 patients approached, 2301 (89.4%) participated. Of the 18.4% of respondents who lacked a regular source of medical care, 65% used the ED as their usual source of healthcare. The overall rate of vaccine hesitancy was 39%; the range among the 15 sites was 28 to 58%. Respondents who lacked a regular source of medical care were more commonly vaccine hesitant than those who had a regular source of medical care (47 vs 38%, 9% difference, 95% CI 4 – 14%). Other characteristics associated with greater vaccine hesitancy were younger age, female gender, African American race, Latinx ethnicity, and not having received an influenza vaccine in the past five years. Of the 61% COVID-19 vaccine acceptors, 21% stated that they lacked a primary doctor or clinic to receive it; the vast majority (95%) of these respondents would accept the COVID-19 vaccine as part of their care in the ED.
ED patients who lack a regular source of medical care are particularly hesitant to COVID-19 vaccination. Most COVID-19 vaccine acceptors would accept it as part of their care in the ED. EDs may have pivotal roles in COVID-19 vaccine messaging and delivery to highly vulnerable populations.
•Evaluated incorporation of FSH in an estrous synchronization protocol for TAI.•Incorporation of FSH did not affect TAI or overall pregnancy rates of cows or heifers.•Cows expressing estrus before AI ...had a greater TAI pregnancy rate.•The TAI pregnancy rate in heifers was similar, regardless of estrous response before AI.
One-hundred-eighty crossbred beef cows and 66 crossbred beef heifers across three locations were stratified by body weight (BW), body condition score (BCS), and age (within location) to evaluate administration of follicle stimulating hormone (FSH) on Day 2 using a modified 7-day CO-Synch plus CIDR® protocol (Day 0=CIDR insertion) with timed-artificial insemination (TAI) at 72h (cows) or 54h (heifers) following CIDR removal. Estrous response following CIDR removal was determined using an Estrotect patch and TAI and final pregnancy rates were determined by transrectal ultrasonography 42–45days following TAI and ≥45days following removal of clean-up bulls. Estrous response rate, TAI and final pregnancy rates for cows were not affected (P≥0.65) by treatment. Cows that exhibited estrus had greater (P<0.01) TAI pregnancy rate (66%) than cows not exhibiting estrus (38%). There was an estrous response by postpartum length interaction (P=0.02) where cows exhibiting estrus and ≥55days postpartum had greater TAI pregnancy rates (75%) compared to cows not exhibiting estrus and <55days postpartum (39%) or ≥55days postpartum (28%). For heifers, timed AI (P=0.46) and final pregnancy rates (P=0.45) were similar across treatments and estrous response had no effect (P=0.30) on TAI pregnancy rates. In conclusion, the addition of FSH to the CO-Synch plus CIDR estrous synchronization protocol did not increase TAI pregnancy rates in beef cows or heifers. However, a positive estrous response to the synchronization protocol was associated with increased TAI pregnancy rates in cows.
Marine aquaculture presents an opportunity for increasing seafood production in the face of growing demand for marine protein and limited scope for expanding wild fishery harvests. However, the ...global capacity for increased aquaculture production from the ocean and the relative productivity potential across countries are unknown. Here, we map the biological production potential for marine aquaculture across the globe using an innovative approach that draws from physiology, allometry and growth theory. Even after applying substantial constraints based on existing ocean uses and limitations, we find vast areas in nearly every coastal country that are suitable for aquaculture. The development potential far exceeds the space required to meet foreseeable seafood demand; indeed, the current total landings of all wild-capture fisheries could be produced using less than 0.015% of the global ocean area. This analysis demonstrates that suitable space is unlikely to limit marine aquaculture development and highlights the role that other factors, such as economics and governance, play in shaping growth trajectories. We suggest that the vast amount of space suitable for marine aquaculture presents an opportunity for countries to develop aquaculture in a way that aligns with their economic, environmental and social objectives.
ABSTRACT
Using a 1D Lagrangian code specifically designed to assess the impact of multiple, time-resolved supernovae (SNe) from a single-star cluster on the surrounding medium, we test three commonly ...used feedback recipes: delayed cooling (e.g. used in the gasoline-2 code), momentum-energy injection (a resolution-dependent transition between momentum-dominated feedback and energy-dominated feedback used, e.g. in the fire-2 code), and simultaneous energy injection (e.g. used in the EAGLE simulations). Our work provides an intermediary test for these recipes: we analyse a setting that is more complex than the simplified scenarios for which many were designed, but one more controlled than a full galactic simulation. In particular, we test how well these models reproduce the enhanced momentum efficiency seen for an 11 SN cluster simulated at high resolution (0.6 pc; a factor of 12 enhancement relative to the isolated SN case) when these subgrid recipes are implemented in low resolution (20 pc) runs. We find that: (1) the delayed cooling model performs well – resulting in 9 times the momentum efficiency of the fiducial isolated SN value – when SNe are clustered and 1051 erg are injected per SN, while clearly overpredicting the momentum efficiency in the single SN test case; (2) the momentum-energy model always achieves good results, with a factor of 5 boost in momentum efficiency; and (3) injecting the energy from all SNe simultaneously does little to prevent overcooling and greatly underproduces the momentum deposited by clustered SNe, resulting in a factor of 3 decrease in momentum efficiency on the average.
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