Interactions of Arbuscular Mychorrhizal Fungi and Bacterial Endophytes on Disease Resistance of Common Root Pathogens in Wheat

Arbuscular mycorrhiza, a symbiosis between plants and fungi, help plants to capture nutrients such as phosphorus (P), nitrogen (N) and other micronutrients from the aggre in exchange for up to 20% of the fixed carbon (C) from the plant. In addition, arbuscular mycorrhizal (AM) fungi can improve the resistance against abiotic (drought, salinity), and also biotic (pathogen) stresses. Bacterial endophytes promote plant growth and yield by fixing N2 from the atmosphere, assimilating N and transfer it to the plant. Bacterial endophytes can also solubilize phosphate and stimulate plant defense responses, suppressing pathogens. The host plant provides sucrose and a favorable place to live for the symbionts. Common root rot and foot or crown rot diseases are among the most common and destructive root diseases of wheat in South Dakota and represent a threat to yield productivity in every growing season. The goal of these studies was to examine whether AM fungi and bacterial endophytes can increase resistance of the plant against common root pathogens Bipolaris sorokiniana, and Fusarium acuminatum. We conducted greenhouse experiments to evaluate plant and seed biomass, seed count, root colonization with AM fungi, along with disease symptoms using two wheat cultivars. Our findings show that root colonization by AM fungi and bacterial endophytes can cause positive growth responses in the shoot and root at early time points and the plants don’t show a yield decrease after pathogen inoculation. The current management practices against common root and crown rot include rotation with broadleaf crops, seed treatment with fungicides and use of resistant seed cultivars. This research explores some of the many effects of AM fungi and bacterial endophytes on resistance to wheat root pathogens in the symbiotic relationship between fungi, bacteria and the host plant. Early application of AM fungi and bacterial endophytes can have a positive effect on wheat yield, reduce the addition of pesticides to the environment, assist cultivars in resistance to fungal diseases, and are a source of nutrients and growth stimulants for plants

Highway increases concentrations of toxic metals in giant panda habitat

The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered

The Physical Drivers and Observational Tracers of CO-to-H2 Conversion Factor Variations in Nearby Barred Galaxy Centers

The CO-to-H-2 conversion factor (alpha CO) is central to measuring the amount and properties of molecular gas. It is known to vary with environmental conditions, and previous studies have revealed lower alpha CO in the centers of some barred galaxies on kiloparsec scales. To unveil the physical drivers of such variations, we obtained Atacama Large Millimeter/submillimeter Array bands (3), (6), and (7) observations toward the inner similar to 2 kpc of NGC 3627 and NGC 4321 tracing (CO)-C-12, (CO)-C-13, and (CO)-O-18 lines on similar to 100 pc scales. Our multiline modeling and Bayesian likelihood analysis of these data sets reveal variations of molecular gas density, temperature, optical depth, and velocity dispersion, which are among the key drivers of aCO. The central 300 pc nuclei in both galaxies show strong enhancement of temperature Tk greater than or similar to 100 K and density n(H2) > 10(3) cm(-3). Assuming a CO-to-H-2 abundance of 3 x 10(-4), we derive 4-15 times lower alpha(CO) than the Galactic value across our maps, which agrees well with previous kiloparsec-scale measurements. Combining the results with our previous work on NGC 3351, we find a strong correlation of alpha(CO) with low-J (CO)-C-12 optical depths (tau(CO)), as well as an anticorrelation with Tk. The tCO correlation explains most of the aCO variation in the three galaxy centers, whereas changes in T-k influence alpha(CO) to second order. Overall, the observed line width and (CO)-C-12/(CO)-C-13 2-1 line ratio correlate with tCO variation in these centers, and thus they are useful observational indicators for alpha(CO) variation. We also test current simulation-based alpha(CO) prescriptions and find a systematic overprediction, which likely originates from the mismatch of gas conditions between our data and the simulations

A constant N2_2H+^+(1-0)-to-HCN(1-0) ratio on kiloparsec scales

Nitrogen hydrides such as NH$_3$ and N$_2$H$^+$ are widely used by Galactic observers to trace the cold dense regions of the interstellar medium. In external galaxies, because of limited sensitivity, HCN has become the most common tracer of dense gas over large parts of galaxies. We provide the first systematic measurements of N$_2$H$^+$(1-0) across different environments of an external spiral galaxy, NGC6946. We find a strong correlation ($r>0.98,p<0.01$) between the HCN(1-0) and N$_2$H$^+$(1-0) intensities across the inner $\sim8\mathrm{kpc}$ of the galaxy, at kiloparsec scales. This correlation is equally strong between the ratios N$_2$H$^+$(1-0)/CO(1-0) and HCN(1-0)/CO(1-0), tracers of dense gas fractions ($f_\mathrm{dense}$). We measure an average intensity ratio of N$_2$H$^+$(1-0)/HCN(1-0)$=0.15\pm0.02$ over our set of five IRAM-30m pointings. These trends are further supported by existing measurements for Galactic and extragalactic sources. This narrow distribution in the average ratio suggests that the observed systematic trends found in kiloparsec-scale extragalactic studies of $f_\mathrm{dense}$ and the efficiency of dense gas (SFE$_\mathrm{dense}$) would not change if we employed N$_2$H$^+$(1-0) as a more direct tracer of dense gas. At kiloparsec scales our results indicate that the HCN(1-0) emission can be used to predict the expected N$_2$H$^+$(1-0) over those regions. Our results suggest that, even if HCN(1-0) and N$_2$H$^+$(1-0) trace different density regimes within molecular clouds, subcloud differences average out at kiloparsec scales, yielding the two tracers proportional to each other.Comment: Accepted for publication in Astronomy & Astrophysic

Linking stellar populations to H II regions across nearby galaxies I. Constraining pre-supernova feedback from young clusters in NGC 1672

Context. Stellar feedback is one of the fundamental factors regulating the evolution of galaxies. However, we still do not have access to strong observational constraints on the relative importance of the different feedback mechanisms (e.g. radiation, ionised gas pressure, stellar winds) in driving Ha II region evolution and molecular cloud disruption. To quantify and compare the different feedback mechanisms, the size of an Ha II region is crucial, whereas samples of well-resolved Ha II regions are scarce. Aims. We constrain the relative importance of the various feedback mechanisms from young massive star populations by resolving Ha II regions across the disk of the nearby star-forming galaxy NGC 1672. Methods. We combined measurements of ionised gas nebular lines obtained by PHANGS-MUSE, with high-resolution (PSF FWHM ∼ 0.1 ∼10 pc) imaging from Hubble Space Telescope (HST) in both the narrow-band Hα and broad-band (NUV, U, B, V, I) filters. We identified a sample of 40 isolated, compact Ha II regions in the HST Hα image. We measured the sizes of these Ha II regions, which were previously unresolved in seeing-limited ground-based observations. In addition, we identified the ionisation source(s) for each Ha II region from catalogues produced as part of the PHANGS-HST survey. In doing so, we were able to link young stellar populations with the properties of their surrounding Ha II regions. Results. The HST observations allowed us to resolve all 40 regions, with radii between 5 and 40 pc. The Ha II regions investigated here are mildly dominated by thermal or wind pressure, yet their elevation above the radiation pressure is within the expected uncertainty range. We see that radiation pressure provides a substantially higher contribution to the total pressure than previously found in the literature over similar size scales. In general, we find higher pressures within more compact Ha II regions, which is driven by the inherent size scaling relations of each pressure term, albeit with significant scatter introduced by the variation in the stellar population properties (e.g. luminosity, mass, age, metallicity). Conclusions. For nearby galaxies, the combination of MUSE/VLT observations with stellar population and resolved Hα observations from HST provides a promising approach that could yield the statistics required to map out how the importance of different stellar feedback mechanisms evolve over the lifetime of a Ha II region

Stewardship Prompts to Improve Antibiotic Selection for Pneumonia

ImportancePneumonia is the most common infection requiring hospitalization and is a major reason for overuse of extended-spectrum antibiotics. Despite low risk of multidrug-resistant organism (MDRO) infection, clinical uncertainty often drives initial antibiotic selection. Strategies to limit empiric antibiotic overuse for patients with pneumonia are needed.ObjectiveTo evaluate whether computerized provider order entry (CPOE) prompts providing patient- and pathogen-specific MDRO infection risk estimates could reduce empiric extended-spectrum antibiotics for non-critically ill patients admitted with pneumonia.Design, setting, and participantsCluster-randomized trial in 59 US community hospitals comparing the effect of a CPOE stewardship bundle (education, feedback, and real-time MDRO risk-based CPOE prompts; n = 29 hospitals) vs routine stewardship (n = 30 hospitals) on antibiotic selection during the first 3 hospital days (empiric period) in non-critically ill adults (≥18 years) hospitalized with pneumonia. There was an 18-month baseline period from April 1, 2017, to September 30, 2018, and a 15-month intervention period from April 1, 2019, to June 30, 2020.InterventionCPOE prompts recommending standard-spectrum antibiotics in patients ordered to receive extended-spectrum antibiotics during the empiric period who have low estimated absolute risk (&lt;10%) of MDRO pneumonia, coupled with feedback and education.Main outcomes and measuresThe primary outcome was empiric (first 3 days of hospitalization) extended-spectrum antibiotic days of therapy. Secondary outcomes included empiric vancomycin and antipseudomonal days of therapy and safety outcomes included days to intensive care unit (ICU) transfer and hospital length of stay. Outcomes compared differences between baseline and intervention periods across strategies.ResultsAmong 59 hospitals with 96 451 (51 671 in the baseline period and 44 780 in the intervention period) adult patients admitted with pneumonia, the mean (SD) age of patients was 68.1 (17.0) years, 48.1% were men, and the median (IQR) Elixhauser comorbidity count was 4 (2-6). Compared with routine stewardship, the group using CPOE prompts had a 28.4% reduction in empiric extended-spectrum days of therapy (rate ratio, 0.72 [95% CI, 0.66-0.78]; P &lt; .001). Safety outcomes of mean days to ICU transfer (6.5 vs 7.1 days) and hospital length of stay (6.8 vs 7.1 days) did not differ significantly between the routine and CPOE intervention groups.Conclusions and relevanceEmpiric extended-spectrum antibiotic use was significantly lower among adults admitted with pneumonia to non-ICU settings in hospitals using education, feedback, and CPOE prompts recommending standard-spectrum antibiotics for patients at low risk of MDRO infection, compared with routine stewardship practices. Hospital length of stay and days to ICU transfer were unchanged.Trial registrationClinicalTrials.gov Identifier: NCT03697070

Stewardship Prompts to Improve Antibiotic Selection for Urinary Tract Infection

ImportanceUrinary tract infection (UTI) is the second most common infection leading to hospitalization and is often associated with gram-negative multidrug-resistant organisms (MDROs). Clinicians overuse extended-spectrum antibiotics although most patients are at low risk for MDRO infection. Safe strategies to limit overuse of empiric antibiotics are needed.ObjectiveTo evaluate whether computerized provider order entry (CPOE) prompts providing patient- and pathogen-specific MDRO risk estimates could reduce use of empiric extended-spectrum antibiotics for treatment of UTI.Design, setting, and participantsCluster-randomized trial in 59 US community hospitals comparing the effect of a CPOE stewardship bundle (education, feedback, and real-time and risk-based CPOE prompts; 29 hospitals) vs routine stewardship (n = 30 hospitals) on antibiotic selection during the first 3 hospital days (empiric period) in noncritically ill adults (≥18 years) hospitalized with UTI with an 18-month baseline (April 1, 2017-September 30, 2018) and 15-month intervention period (April 1, 2019-June 30, 2020).InterventionsCPOE prompts recommending empiric standard-spectrum antibiotics in patients ordered to receive extended-spectrum antibiotics who have low estimated absolute risk (&lt;10%) of MDRO UTI, coupled with feedback and education.Main outcomes and measuresThe primary outcome was empiric (first 3 days of hospitalization) extended-spectrum antibiotic days of therapy. Secondary outcomes included empiric vancomycin and antipseudomonal days of therapy. Safety outcomes included days to intensive care unit (ICU) transfer and hospital length of stay. Outcomes were assessed using generalized linear mixed-effect models to assess differences between the baseline and intervention periods.ResultsAmong 127 403 adult patients (71 991 baseline and 55 412 intervention period) admitted with UTI in 59 hospitals, the mean (SD) age was 69.4 (17.9) years, 30.5% were male, and the median Elixhauser Comorbidity Index count was 4 (IQR, 2-5). Compared with routine stewardship, the group using CPOE prompts had a 17.4% (95% CI, 11.2%-23.2%) reduction in empiric extended-spectrum days of therapy (rate ratio, 0.83 [95% CI, 0.77-0.89]; P &lt; .001). The safety outcomes of mean days to ICU transfer (6.6 vs 7.0 days) and hospital length of stay (6.3 vs 6.5 days) did not differ significantly between the routine and intervention groups, respectively.Conclusions and relevanceCompared with routine stewardship, CPOE prompts providing real-time recommendations for standard-spectrum antibiotics for patients with low MDRO risk coupled with feedback and education significantly reduced empiric extended-spectrum antibiotic use among noncritically ill adults admitted with UTI without changing hospital length of stay or days to ICU transfers.Trial registrationClinicalTrials.gov Identifier: NCT03697096

Relationships between heavy metal concentrations in three different body fluids and male reproductive parameters: a pilot study

<p>Abstract</p> <p>Background</p> <p>Animal studies have shown the reproductive toxicity of a number of heavy metals. Very few human observational studies have analyzed the relationship between male reproductive function and heavy metal concentrations in diverse biological fluids.</p> <p>Methods</p> <p>The current study assessed the associations between seminal and hormonal parameters and the concentration of the 3 most frequent heavy metal toxicants (lead, cadmium and mercury) in three different body fluids. Sixty one men attending infertility clinics that participated in a case-control study to explore the role of environmental toxins and lifestyles on male infertility were analyzed. Concentration of lead, cadmium and mercury were measured in blood and seminal plasma and whole blood using anodic stripping voltammetry and atomic absorption spectrophotometry. Serum samples were analyzed for follicle-stimulating hormone, luteinizing hormone and testosterone. Semen analyses were performed according to World Health Organization criteria. Mann-Whitney test and Spearman's rank correlations were used for unadjusted analyses. Multiple linear regression models were performed controlling for age, body mass index and number of cigarettes per day.</p> <p>Results</p> <p>There were no significant differences between cases and controls in the concentrations of heavy metals in any of the three body fluids. In multivariate analyses using all subjects no significant associations were found between serum hormone levels and metal concentrations. However there was a significant positive association between the percentage of immotile sperms and seminal plasma levels of lead and cadmium.</p> <p>Conclusions</p> <p>Our results suggest that the presence of lead and cadmium in the reproductive tract of men may be related to a moderate alteration of their seminal parameters.</p

PHANGS-JWST First Results: Multiwavelength View of Feedback-driven Bubbles (the Phantom Voids) across NGC 628

We present a high-resolution view of bubbles within the Phantom Galaxy (NGC 628), a nearby (similar to 10 Mpc), star-forming (similar to 2 M (circle dot) yr(-1)), face-on (i similar to 9 degrees) grand-design spiral galaxy. With new data obtained as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS)-JWST treasury program, we perform a detailed case study of two regions of interest, one of which contains the largest and most prominent bubble in the galaxy (the Phantom Void, over 1 kpc in diameter), and the other being a smaller region that may be the precursor to such a large bubble (the Precursor Phantom Void). When comparing to matched-resolution H alpha observations from the Hubble Space Telescope, we see that the ionized gas is brightest in the shells of both bubbles, and is coincident with the youngest (similar to 1 Myr) and most massive (similar to 10(5) M (circle dot)) stellar associations. We also find an older generation (similar to 20 Myr) of stellar associations is present within the bubble of the Phantom Void. From our kinematic analysis of the H I, H-2 (CO), and H ii gas across the Phantom Void, we infer a high expansion speed of around 15 to 50 km s(-1). The large size and high expansion speed of the Phantom Void suggest that the driving mechanism is sustained stellar feedback due to multiple mechanisms, where early feedback first cleared a bubble (as we observe now in the Precursor Phantom Void), and since then supernovae have been exploding within the cavity and have accelerated the shell. Finally, comparison to simulations shows a striking resemblance to our JWST observations, and suggests that such large-scale, stellar-feedback-driven bubbles should be common within other galaxies

PHANGS-JWST: Data-processing Pipeline and First Full Public Data Release

The exquisite angular resolution and sensitivity of JWST are opening a new window for our understanding of the Universe. In nearby galaxies, JWST observations are revolutionizing our understanding of the first phases of star formation and the dusty interstellar medium. Nineteen local galaxies spanning a range of properties and morphologies across the star-forming main sequence have been observed as part of the PHANGS-JWST Cycle 1 Treasury program at spatial scales of ∼5-50 pc. Here, we describe pjpipe, an image-processing pipeline developed for the PHANGS-JWST program that wraps around and extends the official JWST pipeline. We release this pipeline to the community as it contains a number of tools generally useful for JWST NIRCam and MIRI observations. Particularly for extended sources, pjpipe products provide significant improvements over mosaics from the MAST archive in terms of removing instrumental noise in NIRCam data, background flux matching, and calibration of relative and absolute astrometry. We show that slightly smoothing F2100W MIRI data to 0.′′9 (degrading the resolution by about 30%) reduces the noise by a factor of ≈3. We also present the first public release (DR1.1.0) of the pjpipe processed eight-band 2-21 μm imaging for all 19 galaxies in the PHANGS-JWST Cycle 1 Treasury program. An additional 55 galaxies will soon follow from a new PHANGS-JWST Cycle 2 Treasury program