Bacteria are considered as playing a predominant role in the production of nitrous oxide (N2O) in arable soil. Despite the knowledge that fungi are able to denitrify their contribution to denitrifier ...N2O production from arable soil is uncertain. Here, we assess the capability of fungi and bacteria to contribute to N2O emission from arable soil by measuring potential denitrification rates (PDR) as N2O production, after application of selective inhibitors aimed at distinguishing between fungal and bacterial denitrification, and related PDR to characteristics of the soil microbial community. Soil was sampled from a long-term crop rotation maintained since 1961 at seven different pH levels, ranging in 0.5 increments from pH 4.5 to 7.5, and along a cultivation gradient from freshly ploughed soil to three years under ley grass. Over both pH and cultivation gradients, bacteria contributed up to 54% and fungi contributed to 18% of the PDR. Residual N2O production that was not targeted by the selective inhibitors and hence could not be attributed to fungi or bacteria might be due to pre-synthesised enzymes or resistant organisms. The PDR of the bacterial community responded positively to increase in soil pH with the lowest PDR at pH 4.2 and the highest around pH 5.9. In contrast, fungal denitrification was not influenced by soil pH. Changes in ester linked fatty acids (ELFA) concentrations showed that whilst total bacterial biomass decreased with increasing pH fungal biomass was not significantly influenced by pH, driving an increase in the ratio of fungal–bacterial biomass. Both fungal biomass and bacterial biomass, and the PDR from the control treatment (no inhibitor application) across the pH gradient were greatest under long-term ley. Concentrations of fatty acids a15:0, 16:1ω7 and 17:1ω8 of microbial origin were positively correlated with the proportion of denitrification activity that was repressed by bacterial inhibitors. This suggests that there is a relationship between organisms that possess the fatty acids a15:0, 16:1ω7 and 17:1ω8, and the function of denitrification. Our results demonstrate that both fungal and bacterial denitrification were occurring in this arable soil. That management for pH and cultivation had differing effects on the potential contribution of fungal and bacterial denitrification to N2O production has implications for the development of appropriate management practices for mitigation of this greenhouse gas.
► Fungal denitrification is significant in arable soil. ► Proportion of fungal denitrification was stable over pH and cultivation gradients. ► Bacterial denitrification was influenced by both pH and cultivation. ► ELFA markers correlate to bacterial denitrification.
Rilpivirine long‐acting (RPV‐LA) is a parenteral formulation enabling prolonged plasma exposure. We explored its multiple‐compartment pharmacokinetics (PK) after a single dose, for pre‐exposure ...prophylaxis. Sixty‐six HIV‐negative volunteers were enrolled: women received an intramuscular dose of 300, 600, or 1,200 mg, with plasma and genital levels measured to 84 days postdose; men receiving 600 mg had similar PK determined in plasma and rectum. Ex vivo antiviral activity of cervicovaginal lavage (CVL) was also assessed. After a single dose, RPV concentrations peaked at days 6–8 and were present in plasma and genital‐tract fluid to day 84. Vaginal and male rectal tissue levels matched those in plasma. At the 1,200 mg dose, CVL showed greater antiviral activity, above baseline, at days 28 and 56. All doses were well tolerated. All doses gave prolonged plasma and genital‐tract rilpivirine exposure. PK and viral inhibition of repeated doses will be important in further dose selection.
Clinical Pharmacology & Therapeutics (2014); 96 3, 314–323. advance online publication 25 June 2014. doi:10.1038/clpt.2014.118
Acoustic impulse resonance frequency sensor and miniaturized VIS/NIR spectrometer were applied on apple fruit
Malus domestica ‘Idared’ and ‘Golden Delicious’ (
n
=
800) to predict fruit flesh ...firmness and soluble solids content (SSC) on tree and in shelf life. Partial least-squares calibration models on acoustic data and VIS spectra of ‘Golden Delicious’/‘Idared’ apple fruits on tree were built for predicting the fruit flesh firmness: coefficients of determination (
R
2) and standard errors of cross-validation (SECV) of
R
2
=
0.93/0.81 and SECV
=
7.73/10.50 N/cm
2 were calculated. SSC prediction of freshly harvested apples using NIR spectrometry was obtained with
R
2
=
0.20/0.41 and SECV
=
1.29/0.94 °Brix. Prediction of SSC and fruit flesh firmness of stored ‘Golden Delicious’/‘Idared’ apple fruits showed high errors or was not possible.
The fruit maturity stage on tree was predicted as classes based on calendar weeks for ‘Golden Delicious’/‘Idared’ apple fruits with 64%/66% correct classification and 92%/84% correct plus neighboring class with SECV
=
0.9/0.9 weeks. Classes of ‘Golden Delicious’/‘Idared’ apple fruit at different quality levels due to different storage conditions were non-destructively discriminated with 77%/84% correctly classified fruits and 93%/99% correct plus neighboring class with SECV
=
0.8/0.5 classes.
The results show the potential of non-destructive sensors for predicting accepted fruit parameters enabling the determination of optimum harvest date and fruit quality in shelf life.
Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections in children have occurred primarily in individuals with recognized predisposing risks. Community-acquired MRSA ...infections in the absence of identified risk factors have been reported infrequently.
To determine whether community-acquired MRSA infections in children with no identified predisposing risks are increasing and to define the spectrum of disease associated with MRSA isolation.
Retrospective review of medical records.
Hospitalized children with S aureus isolated between August 1988 and July 1990 (1988-1990) and between August 1993 and July 1995 (1993-1995).
The University of Chicago Children's Hospital.
Prevalence of community-acquired MRSA over time, infecting vs colonizing isolates, and risk factors for disease.
The number of children hospitalized with community-acquired MRSA disease increased from 8 in 1988-1990 to 35 in 1993-1995. Moreover, the prevalence of community-acquired MRSA without identified risk increased from 10 per 100000 admissions in 1988-1990 to 259 per 100000 admissions in 1993-1995 (P<.001), and a greater proportion of isolates produced clinical infection. The clinical syndromes associated with MRSA in children without identified risk were similar to those associated with community-acquired methicillin-susceptible S aureus. Notably, 7 (70%) of 10 community-acquired MRSA isolates obtained from children with an identified risk were nonsusceptible to at least 2 drugs, compared with only 6 (24%) of 25 isolates obtained from children without an identified risk (P=.02).
These findings demonstrate that the prevalence of community-acquired MRSA among children without identified risk factors is increasing.
Objective
To evaluate the influence of Fingolimod treatment on B‐cell subset composition and function in multiple sclerosis patients and its potential clinical relevance.
Methods
Subset composition ...and cytokine production of B cells derived from peripheral blood mononuclear cells from multiple sclerosis patients under Fingolimod treatment, untreated multiple sclerosis patients and healthy controls were analyzed by flow cytometry and ELISA. Migration of lymphocyte subsets across primary human brain microvascular endothelial cells was assessed in an in vitro transmigration assay. Cell numbers and composition of B‐cell subsets in cerebrospinal fluid and peripheral blood were determined by flow cytometry. Regulatory B‐cell frequencies were correlated with parameters of disease stability.
Results
Within the peripheral B‐cell compartment of Fingolimod‐treated patients, the proportion of regulatory B cells (CD38+CD27−CD24+CD5+) was significantly increased as compared to treatment‐naïve multiple sclerosis patients and to healthy controls, and significantly more regulatory B cells produced Interleukin‐10. Fingolimod treatment enhanced the capacity of regulatory B cells to transmigrate across brain endothelial cells in an in vitro model of the blood‐brain‐barrier. In line with these findings, the cerebrospinal fluid/blood ratio of total B cells and regulatory B cells was strongly increased by Fingolimod treatment, and patients exhibited increased regulatory B‐cell frequencies in the cerebrospinal fluid. Finally, elevated regulatory B‐cell percentages in the periphery significantly correlated with clinical and paraclinical disease stability.
Interpretation
These data suggest a novel and as yet unrecognized role of Fingolimod in correction of the imbalance between regulatory and effector B‐cell functions in multiple sclerosis both by direct effects and indirect partitioning effects on B‐cell subpopulations.
Cumulative data support the judicious use of live attenuated vaccines posttransplant in select pediatric solid organ recipients. See article by Posfay‐Barbe et al on page 2974.
Background. Annual influenza vaccination is routinely recommended for pediatric solid organ transplant recipients. However, there are limited data defining the immune response to the inactivated ...vaccine in this population. Methods. This prospective study compared the humoral and cell-mediated immune responses to the trivalent subvirion influenza vaccine in pediatric liver transplant recipients with those in their healthy siblings. All subjects received inactivated influenza vaccine. Hemagglutination inhibition and interferon-γ (IFN-γ) enzyme-linked immunosorbent spot assays for New Caledonia and Shanghai strains were performed at baseline, after each vaccine dose, and 3 months after the series. Seroconversion was defined as a 4-fold increase in antibody titers; seroprotection was defined as an antibody titer ⩾1:40. An increase in the number of T cells secreting IFN-γ was considered to be a positive enzyme-linked immunosorbent spot response. Results. After 1 dose of vaccine, transplant recipients achieved rates of antibody seroprotection and seroconversion that were similar to those achieved by their healthy siblings. However, for both influenza strains, IFN-γ responses by enzyme-linked immunosorbent spot were significantly attenuated in transplant recipients after 2 doses of vaccine. No cases of influenza or vaccine-related serious adverse events were documented in the study. Conclusions. The diminished cell-mediated immune response to influenza vaccination that was observed in pediatric liver transplant recipients suggests that the current vaccine strategy may not provide optimal protection. Because of concerns regarding potential emergence of more virulent influenza strains, further studies are warranted to determine if IFN-γ responses are predictive of efficacy and to identify the optimal vaccination strategy to protect populations with a high risk of infection.
Tropheryma whipplei is the causative agent of Whipple's disease and has been detected in stools of asymptomatic carriers. Colonization has been associated with precarious hygienic conditions. There ...is a lack of knowledge about the epidemiology and transmission characteristics on a population level, so the aim of this study was to determine the overall and age-specific prevalence of T. whipplei and to identify risk factors for colonization. This molecular epidemiological survey was designed as a cross-sectional study in a rural community in Central African Gabon and inhabitants of the entire community were invited to participate. Overall prevalence assessed by real-time PCR and sequencing was 19.6% (95% CI 16–23.2%, n = 91) in 465 stool samples provided by the study participants. Younger age groups showed a significantly higher prevalence of T. whipplei colonization ranging from 40.0% (95% CI 27.8–52.2) among the 0–4 year olds to 36.4% (95% CI 26.1–46.6) among children aged 5–10 years. Prevalence decreased in older age groups (p <0.001) from 12.6% (95% CI 5.8–19.4%; 11–20 years) to 9.7% (95% CI 5.7–13.6) among those older than 20. Risk factor analysis revealed young age, male sex, and number of people sharing a bed as factors associated with an increased risk for T. whipplei carriage. These results demonstrate that T. whipplei carriage is highly prevalent in this part of Africa. The high prevalence in early life and the analysis of risk factors suggest that transmission may peak during childhood facilitated through close person-to-person contacts.
Systemic aciclovir and its prodrug valaciclovir are effective in treating and reducing recurrences of genital herpes simplex virus (HSV) and reducing transmission. Local aciclovir delivery, if it can ...achieve and maintain comparable intracellular genital tract levels, may be equally effective in the treatment and suppression of genital HSV. Intravaginal ring (IVR) delivery of aciclovir may provide pre-exposure prophylaxis against HSV acquisition.
Tolerability and pharmacokinetics were evaluated in six HIV-negative women with recurrent genital HSV who switched their daily oral valaciclovir suppression to an aciclovir IVR for 7 days (n = 3) or 14 days (n = 3). Blood and cervicovaginal lavage (CVL) were collected after oral and IVR dosing to measure aciclovir concentrations and genital swabs were obtained to quantify HSV shedding by PCR.
The rings were well tolerated. Median plasma aciclovir concentrations were 110.2 ng/mL (IQR, 85.9-233.5) 12-18 h after oral valaciclovir. Little or no drug was detected in plasma following IVR dosing. Median (IQR) CVL aciclovir levels were 127.3 ng/mL (21-660.8) 2 h after oral valaciclovir, 154.4 ng/mL (60.7-327.5) 12-18 h after oral valaciclovir and 438 ng/mL (178.5-618.5) after 7 days and 393 ng/mL (31.6-1615) after 14 days of aciclovir ring use. Median CVL aciclovir levels 2 h after oral dosing were similar to levels observed 7 (P = 0.99) and 14 (P = 0.75) days after ring use. HSV DNA was not detected in genital swabs and there was no significant change in inflammatory mediators.
This first-in-human study demonstrated that an IVR could safely deliver mucosal levels of aciclovir similar to oral valaciclovir without systemic absorption. More intensive site-specific pharmacokinetic studies are needed to determine whether higher local concentrations are needed to achieve optimal drug distribution within the genital tract.
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