Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants ...can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named "brachialactone," this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a γ-lactone ring. It contributed 60-90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in NITROSOMONAS: Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NHFormula: see text) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NHFormula: see text. Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment.
Abstract
We calculate the implied horizontal heat transport due to the spatial anomalies of radiative fluxes at the top of the atmosphere (TOA). The regional patterns of implied heat transport for ...different components of the TOA fluxes are calculated by solving the Poisson equation with the flux components as source terms. The shortwave (SW) part of the spectrum governs the spatial patterns of the total implied heat transport. Using the cloud radiative effect (CRE) as source term, we show that the direct effect of clouds is to reduce the poleward heat transport in the majority of the Northern Hemisphere and at high southern latitudes. Clouds flatten the gradients of the clear-sky energy flux potential and hence reduce the implied heat transport with respect to clear skies. Clouds reduce the implied cross-equatorial heat transport with respect to clear sky through changes in the SW part of the spectrum. It changes from 0.83 PW in clear sky to −0.01 PW in all sky, equivalent to the hemispheric albedo symmetry reported in previous studies. We investigate hemispheric symmetry by introducing a metric that measures the symmetry of implied meridional heat transports at all latitudes. The direct effect of clouds is to increase the symmetry in the implied heat transport, and this is achieved through an increase in symmetry in the SW part of the spectrum in the tropics. Whether this is trivial or the result of a fundamental control in the climate system is still an open question.
Abstract Faced with the uncertainty of whether the vaccines against Covid-19 are effective or not and faced with living or dying, it is important to know the perception and expectation of their ...acceptance. The main aim of the study to analyze the perception and expectation of the vaccine against Covid- 19 that South American families have in an urban area of De Pasco. Descriptive, cross-sectional study, simple random sampling of 197 families. The participants were recruited digitally through a neighborhood leadership and an online survey was applied with prior consent. The logistic regression analysis was performed in EPIDAT 4.1 with a significance level of 5%. Regarding the desire to be vaccinated, it is worth noting that a family member died from the coronavirus, hence the health personnel must continue with the preventive promotional work of vaccination in order to obtain favorable results in the entire population. The majority (100%) have a favorable perception and expectation about the vaccine against Covid- 19 ( X c 2=132.83) and the p-value (0.00); As regards the desire to be vaccinated, it is worth noting having had a family member die from the coronavirus, hence the health personnel must continue with the preventive promotional work of vaccination in order to obtain favorable results in the entire population.
Resumo Diante da incerteza quanto à eficácia das vacinas contra a Covid-19 e diante da possibilidade de viver ou morrer, é importante conhecer a percepção e a expectativa de sua aceitação por parte da população. O objetivo principal do presente estudo é analisar a como a vacina contra a Covid-19 é vista pela população estudada e quais são as expectativas que famílias sul-americanas de uma área urbana de Pasco têm em relação a esta vacina. Este é um estudo descritivo, transversal, usando uma amostragem aleatória simples de 197 famílias. Os participantes foram selecionados digitalmente através do contato com uma liderança local e uma pesquisa online foi aplicada com o consentimento prévio dos indivíduos. A análise de regressão logística foi realizada no EPIDAT 4.1 com nível de significância de 5%. Acerca do desejo de se vacinar, é válido enfatizar que há falecimentos de familiares devido ao coronavírus e, portanto, é necessário que a equipe assistencial continue com o trabalho preventivo de incentivo à vacinação para obter resultados favoráveis para toda a população. De acordo com os resultados encontrados no presente estudo, a maioria (100%) dos participantes demonstrou ter uma percepção e expectativa favoráveis sobre a vacina contra a Covid-19 ( X c 2=132,83), com valor-p (0,00).
We present a numerical study of the magnetic properties of ZnFe2O4 using Monte-Carlo simulations performed considering a Heisenberg model with antiferromagnetic couplings determined by Density ...Functional Theory. Our calculations predict that the magnetic susceptibility has a cusp-like peak centered at 13 K, and follows a Curie–Weiss behavior above this temperature with a high and negative Curie–Weiss temperature (ΘCW=−170 K). These results agree with the experimental data once extrinsic contributions that give rise to the deviation from a Curie–Weiss law are discounted. Additionally, we discuss the spin configuration of ZnFe2O4 below its ordering temperature, where the system presents a high degeneracy.
Clozapine is the most effective antipsychotic for patients with treatment-resistant schizophrenia. However, response is highly variable and possible genetic underpinnings of this variability remain ...unknown. Here, we performed polygenic risk score (PRS) analyses to estimate the amount of variance in symptom severity among clozapine-treated patients explained by PRSs (R2) and examined the association between symptom severity and genotype-predicted CYP1A2, CYP2D6, and CYP2C19 enzyme activity. Genome-wide association (GWA) analyses were performed to explore loci associated with symptom severity. A multicenter cohort of 804 patients (after quality control N = 684) with schizophrenia spectrum disorder treated with clozapine were cross-sectionally assessed using the Positive and Negative Syndrome Scale and/or the Clinical Global Impression-Severity (CGI-S) scale. GWA and PRS regression analyses were conducted. Genotype-predicted CYP1A2, CYP2D6, and CYP2C19 enzyme activities were calculated. Schizophrenia-PRS was most significantly and positively associated with low symptom severity (p = 1.03 × 10
; R2 = 1.85). Cross-disorder-PRS was also positively associated with lower CGI-S score (p = 0.01; R2 = 0.81). Compared to the lowest tertile, patients in the highest schizophrenia-PRS tertile had 1.94 times (p = 6.84×10
) increased probability of low symptom severity. Higher genotype-predicted CYP2C19 enzyme activity was independently associated with lower symptom severity (p = 8.44×10
). While no locus surpassed the genome-wide significance threshold, rs1923778 within NFIB showed a suggestive association (p = 3.78×10
) with symptom severity. We show that high schizophrenia-PRS and genotype-predicted CYP2C19 enzyme activity are independently associated with lower symptom severity among individuals treated with clozapine. Our findings open avenues for future pharmacogenomic projects investigating the potential of PRS and genotype-predicted CYP-activity in schizophrenia.
Abstract
Since 2016, the South African Weather Service (SAWS) has been running convective-scale simulations to assist with forecast operations across southern Africa. These simulations are run with a ...tropical configuration of the Met Office Unified Model (UM), nested in the Met Office global model, but without data assimilation. For November 2016, convection-permitting simulations at 4.4- and 1.5-km grid lengths are compared against a simulation at 10-km grid length with convection parameterization (the current UM global atmosphere configuration) to identify the benefits of increasing model resolution for forecasting convection across southern Africa. The simulations are evaluated against satellite rainfall estimates, CloudSat vertical cloud profiles, and SAWS radar data. In line with previous studies using the UM, on a monthly time scale, the diurnal cycle of convection and the distribution of rainfall rates compare better against observations when convection-permitting model configurations are used. The SAWS radar network provides a three-dimensional composite of radar reflectivity for northeast South Africa at 6-min intervals, allowing the evaluation of the vertical development of precipitating clouds and of the timing of the onset of deep convection. Analysis of four case study days indicates that the 4.4-km simulations have a later onset of convection than the 1.5-km simulations, but there is no consistent bias of the simulations against the radar observations across the case studies.
Modifying the extent of fatty acid (FA) biohydrogenation (BH) in the rumen through diet formulation is an effective strategy for changing the content of unsaturated FAs (USFAs) in meat. The present ...study investigated the effects of different sources of forage in high-concentrate diets on intake, digestibility, rumen fermentation, ruminal BH, duodenal flow of FAs and rumen microbiota in Nellore steers. Intake of neutral detergent fibre (NDF) was higher in animals fed with maize silage (MS) than in those fed with sugar cane (SC) and sugar cane bagasse (SB). Higher digestibility of dry matter and NDF was found in animals fed with MS than in those fed with the other diets. In addition, higher crude protein digestibility was observed in animals fed with sugar cane bagasse than in those fed with SC. Non-fibre carbohydrate (NFC) digestibility was higher in animals fed with sugar cane than in those fed with the other diets. Intake of total and individual FAs such as C18 : 1 cis-9, C18 : 2, and C18 : 3 was similar between animals fed with MS and SB, but decreased in animals fed with SC. Diets containing MS and SB showed higher total digestibility of saturated FAs (SFAs) and USFAs, respectively and total FAs and ruminal BH of C18 : 1 and USFA. Intestinal digestibility of overall FAs did not differ among treatments, except for C18 : 3, which increased in animals fed with SC and SB. The profile of FAs in duodenal digesta and faecal outputs did not differ among treatments. However, the flow of NDF was higher in animals fed with SC than in those fed with MS and SB. Animals fed with SB showed higher values of pH than those fed with MS and SC. Animals fed with SC showed lower values of ammonia-nitrogen. Protozoan counts were only influenced by diet for species that belonged to the genera Dasytricha and Isotricha. Populations of fibrolytic bacteria (Ruminococus flavefaciens, Ruminococus albus and Fibrobacter succinogenes) were similar among diets. Populations of Selenomonas ruminantium increased 2·5 and 5 times in animals fed with MS when compared with those fed with SC and SB, respectively. The use of MS increased intake and digestibility of NDF, and the use of SC decreased ruminal BH of total USFA without changing the flow of FAs to the duodenum. Thus, different sources of forage in high-concentrate diets do not modify the duodenal flow of USFA or fibrolytic bacteria. This must be taken into account when formulating diets to modulate ruminal upsets without altering intake.
Eysenhardtia polystachya (Fabaceae) is a valuable medicinal plant from Mexico. There have been no cell culture studies of this plant to produce secondary metabolites. The aim of this work was to ...establish callus and cell suspension cultures of E. polystachya (Ortega) and to evaluate the content of phenols, total flavonoids, and fungicidal activity against Sclerotium cepivorum and Rhizoctonia solani from extracts of wild plant and cell cultures. An efficient protocol for callus induction and cell cultures was established. The maximum percentage of explants inducing callus (100 and 98%) was obtained using 1-naphthaleneacetic acid (8.28μM) plus kinetin (0.41μM) or picloram (4.14μM) plus kinetin (0.41μM), respectively. Only the cell suspension cultures from callus with picloram plus kinetin grew appropriately and the maximum dry biomass accumulation (14gL−1) occurred at 12days of culture. The leaves from wild plants yielded larger amounts of total phenols (155.17mggallic acid equivalentsg−1 dry weight) and total flavonoids (124.3mgquercetin equivalentsg−1 dry weight) compared to cell suspension cultures, which exhibited total phenols amounts of 73.98mggallic acid equivalentsg−1 dry weight and total flavonoids of 16.29mgquercetin equivalentsg−1 dry weight. The fungicide Cercobin® inhibited 100% the S. cepivorum mycelial growth, while 80.0 and 73.0% inhibition was achieved with the ethyl acetate fraction of the dichloromethane extracts from E. polystachya sapwood and heartwood, respectively. However, cell suspension cultures showed only 39% inhibition of S. cepivorum mycelial growth with methanol extracts. The maximum percentage inhibition of R. solani (66.0%) occurred using the hexane fraction of methanolic extracts from cell suspension cultures; however, Cercobin® presented only 33.0% growth inhibition. Extracts of E. polystachya cell suspension cultures can be used as a biotechnological option against phytopathogenic fungi.
•Picloram was the auxin most suitable for inducing callus from E. polystachya leaves.•An efficient protocol for callus induction and cell cultures was established.•Cell suspension cultures produced large amount of total phenolics.•Extracts from cell suspension cultures inhibited the mycelial growth of R. solani.•Dichloromethane extracts of sap wood inhibited the mycelial growth of S. ceviporum.
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