PURPOSE: Liver transplantation (LTx) is performed in individuals with urea cycle disorders when medical management (MM) insufficiently prevents the occurrence of hyperammonemic events. However, there is a paucity of systematic analyses on the effects of LTx on health-related outcome parameters compared to individuals with comparable severity who are medically managed. METHODS: We investigated the effects of LTx and MM on validated health-related outcome parameters, including the metabolic disease course, linear growth, and neurocognitive outcomes. Individuals were stratified into "severe" and "attenuated" categories based on the genotype-specific and validated in vitro enzyme activity. RESULTS: LTx enabled metabolic stability by prevention of further hyperammonemic events after transplantation and was associated with a more favorable growth outcome compared with individuals remaining under MM. However, neurocognitive outcome in individuals with LTx did not differ from the medically managed counterparts as reflected by the frequency of motor abnormality and cognitive standard deviation score at last observation. CONCLUSION: Whereas LTx enabled metabolic stability without further need of protein restriction or nitrogen-scavenging therapy and was associated with a more favorable growth outcome, LTx-as currently performed-was not associated with improved neurocognitive outcomes compared with long-term MM in the investigated urea cycle disorders.

• Klíčová slova
• Argininosuccinic aciduria, Citrullinemia type 1, Liver transplantation, Ornithine transcarbamylase deficiency, Urea cycle disorders,
• MeSH
• hodnocení výsledků zdravotní péče MeSH
• lidé MeSH
• proteiny MeSH
• transplantace jater * MeSH
• vrozené poruchy cyklu močoviny * genetika   chirurgie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• proteiny MeSH

Trichodesmium is an important dinitrogen (N2)-fixing cyanobacterium in marine ecosystems. Recent nucleic acid analyses indicate that Trichodesmium colonies with their diverse epibionts support various nitrogen (N) transformations beyond N2 fixation. However, rates of these transformations and concentration gradients of N compounds in Trichodesmium colonies remain largely unresolved. We combined isotope-tracer incubations, micro-profiling and numeric modelling to explore carbon fixation, N cycling processes as well as oxygen, ammonium and nitrate concentration gradients in individual field-sampled Trichodesmium colonies. Colonies were net-autotrophic, with carbon and N2 fixation occurring mostly during the day. Ten percent of the fixed N was released as ammonium after 12-h incubations. Nitrification was not detectable but nitrate consumption was high when nitrate was added. The consumed nitrate was partly reduced to ammonium, while denitrification was insignificant. Thus, the potential N transformation network was characterised by fixed N gain and recycling processes rather than denitrification. Oxygen concentrations within colonies were ~60-200% air-saturation. Moreover, our modelling predicted steep concentration gradients, with up to 6-fold higher ammonium concentrations, and nitrate depletion in the colony centre compared to the ambient seawater. These gradients created a chemically heterogeneous microenvironment, presumably facilitating diverse microbial metabolisms in millimetre-sized Trichodesmium colonies.

• MeSH
• amoniové sloučeniny metabolismus   MeSH
• autotrofní procesy MeSH
• denitrifikace MeSH
• dusičnany metabolismus   MeSH
• dusík metabolismus   MeSH
• fixace dusíku MeSH
• koloběh dusíku MeSH
• koloběh uhlíku MeSH
• kyslík metabolismus   MeSH
• mořská voda mikrobiologie   MeSH
• nitrifikace MeSH
• oxid uhličitý metabolismus   MeSH
• Trichodesmium metabolismus   MeSH
• uhlík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• amoniové sloučeniny MeSH
• dusičnany MeSH
• dusík MeSH
• kyslík MeSH
• oxid uhličitý MeSH
• uhlík MeSH

Rice (Oryza sativa L.) feeds to two-third of the global population by serving as staple food. It is the main export commodity of several countries; thus, contributes towards foreign exchange earnings. Unfortunately, average global rice yield is far below than its genetic potential. Low nitrogen (N) use efficiency (NUE) is among the major reasons for low average yield. Current study evaluated the impact of nitrogen fertilizer application methods (conventional and deep placement) on growth, yield-related traits, chlorophyll contents, photosynthesis rate, agronomic N-use efficiency (ANUE), partial factors productivity of applied N (PFP) and economic returns of two different transplanted rice varieties (Basmati-515 and Super-Basmati). Fertilizer application methods significantly affected allometry, yield-related traits, chlorophyll contents, photosynthesis rate, ANUE, PFP and economic returns. Deep placement of N-fertilizer (DPNF) observed better allometric traits, high chlorophyll contents, photosynthesis rate, ANUE, PFP, yield attributes and economic returns compared to conventional application of N-fertilizer (CANF). Similarly, Basmati-515 had better allometric and yield-related traits, chlorophyll contents, photosynthesis rate, ANUE, PFP and economic returns than Super-Basmati. Regarding interactions among N-fertilizer application methods and rice varieties, Basmati-515 with DPNF resulted in higher chlorophyll contents, photosynthesis rate, ANUE, PFP, allometric and yield related traits and economic returns than CANF. The lowest values of these traits were observed for Super-Basmati with no application of N-fertilizer. Both varieties had better yield and economic returns with DPNF compared to CANF. It is concluded that DPNF improved yield, ANUE and economic returns; therefore, should be opted to improve productivity of transplanted fine rice. Nonetheless, lower nitrogen doses need to be tested for DPNF to infer whether it could lower N use in rice crop.

• MeSH
• chlorofyl metabolismus   MeSH
• dusík farmakologie   MeSH
• fotosyntéza účinky léků   MeSH
• listy rostlin účinky léků   MeSH
• průmyslová hnojiva * MeSH
• rýže (rod) účinky léků   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• odvolaná publikace MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorofyl MeSH
• dusík MeSH
• průmyslová hnojiva * MeSH

This review critically assesses nitrogen removal technologies applied in the reject water treatment, across different stages of technological development, with a focus on their economic and environmental impacts. The prevalent use of biological processes raises concerns due to potential environmental impacts caused by N2O emissions. However, partial nitritation-anaerobic ammonium oxidation demonstrated economic benefits and the potential for positive environmental outcomes when properly operated and controlled. Furthermore, reject water, in many cases, provides sufficient nitrogen concentrations for nitrogen recovery processes, such as ammonia stripping, substituting production of industrial fertilizers and contributing to a circular economy. Nonetheless, their financial competitiveness is subject to various conditions, including the nitrogen concentration or reject water flow. As the environmental benefits of bioprocesses and economic benefits of nitrogen recovery processes may vary, it is crucial to further optimize both and investigate novel promising technologies such as electrochemical systems, denitrifying anaerobic methane oxidation or direct ammonia oxidation.

• Klíčová slova
• Ammonium nitrogen, Life-cycle assessment, Nitrous oxide, Sidestream treatment, Technology readiness,
• MeSH
• amoniak * MeSH
• bioreaktory MeSH
• denitrifikace * MeSH
• dusík MeSH
• oxidace-redukce MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• amoniak * MeSH
• dusík MeSH

Tree rings provide valuable insight into past environmental changes. This study aimed to evaluate perturbations in tree ring width (TRW) and δ15N alongside soil acidity and nutrient availability gradients caused by the contrasting legacy of air pollution (nitrogen [N] and sulphur [S] deposition) and tree species (European beech, Silver fir and Norway spruce). We found consistent declines of tree ring δ15N, which were temporarily unrelated to the changes in the TRW. The rate of δ15N change in tree rings was related to the contemporary foliar carbon (C) to phosphorus (P) ratio. This observation suggested that the long-term accumulation of 15N depleted N in tree rings, likely mediated by retained N from deposition, was restricted primarily to stands with currently higher P availability. The shifts observed in tree-ring δ15N and TRW suggest that acidic air pollution rather than changes in stand productivity determined alteration of N and C cycles. Stable N isotopes in tree rings provided helpful information on the trajectory of the N cycle over the last century with direct consequences for a better understanding of future interactions among N, P and C cycles in terrestrial ecosystems.

• Klíčová slova
• Eutrophication, Forest productivity, Isotope, Phosphorus, Tree species, nitrogen,
• MeSH
• buk (rod) * MeSH
• dusík MeSH
• ekosystém MeSH
• izotopy dusíku analýza   MeSH
• izotopy uhlíku analýza   MeSH
• lesy MeSH
• smrk * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• izotopy dusíku MeSH
• izotopy uhlíku MeSH

In drylands, where water scarcity limits vascular plant growth, much of the primary production occurs at the soil surface. This is where complex macro- and microbial communities, in an intricate bond with soil particles, form biological soil crusts (biocrusts). Despite their critical role in regulating C and N cycling in dryland ecosystems, there is limited understanding of the fate of biologically fixed C and N from biocrusts into the mineral soil, or how climate change will affect C and N fluxes between the atmosphere, biocrusts, and subsurface soils. To address these gaps, we subjected biocrust-soil systems to experimental warming and drought under controlled laboratory conditions, monitored CO2 fluxes, and applied dual isotopic labeling pulses (13CO2 and 15N2). This allowed detailed quantification of elemental pathways into specific organic matter (OM) pools and microbial biomass via density fractionation and phospholipid fatty acid analyses. While biocrusts modulated CO2 fluxes regardless of the temperature regime, drought severely limited their photosynthetic C uptake to the extent that the systems no longer sustained net C uptake. Furthermore, the effect of biocrusts extended into the underlying 1 cm of mineral soil, where C and N accumulated as mineral-associated OM (MAOM<63μm). This was strongly associated with increased relative dominance of fungi, suggesting that fungal hyphae facilitate the downward C and N translocation and subsequent MAOM formation. Most strikingly, however, these pathways were disrupted in systems exposed to warming, where no effects of biocrusts on the elemental composition of the underlying soil nor on MAOM were determined. This was further associated with reduced net biological N fixation under combined warming and drought, highlighting how changing climatic conditions diminish some of the most fundamental ecosystem functions of biocrusts, with detrimental repercussions for C and N cycling and the persistence of soil organic matter pools in dryland ecosystems.

En regiones áridas, donde la sequía limita el crecimiento de plantas vasculares, gran parte de la producción primaria ocurre en la superficie del suelo. En este lugar, complejas comunidades microbianas, estrechamente ligadas a partículas del suelo, forman costras biológicas (conocidas también como biocostras). Aunque estas biocostras son cruciales para regular los ciclos del carbono (C) y nitrógeno (N) en ecosistemas áridos, aún existe una comprensión limitada del destino hacia el suelo mineral del C y N fijados biológicamente desde las biocostras, o sobre cómo el cambio climático afectará los flujos de C y N entre la atmósfera, las biocostras y los suelos subsuperficiales. Para abordar estas brechas, sometimos sistemas de biocostra y suelo a aumentos de temperatura y sequía experimentales en condiciones controladas de laboratorio, donde monitoreamos los flujos de CO2 y aplicamos pulsos de etiquetado isotópico dual (13CO2 y 15N2). Esto permitió una cuantificación detallada de las vías de incorporación de los elementos en grupos específicos de materia orgánica (MO) y biomasa microbiana mediante fraccionamiento por densidad y análisis de ácidos grasos de fosfolípidos (PLFA). Si bien las biocostras modularon los flujos de CO2 independientemente del régimen de la temperatura, la sequía restringió severamente la captación fotosintética de C hasta el punto de que los sistemas ya no mantuvieron la absorción neta de C. Además, el efecto de las biocostras se extendió hasta 1 cm del suelo bajo esta, donde el C y el N se acumularon como MO asociada a minerales (MAOM<63μm). Esto se relaciona estrechamente con un aumento en la dominancia relativa de hongos, lo que sugiere que las hifas de los hongos facilitan la translocación descendente de C y N y subsecuentemente la formación de MAOM. Sin embargo, lo más sorprendente es que estas vías se vieron interrumpidas en sistemas expuestos al aumento de temperatura, donde no se determinaron efectos de las biocostras en la composición elemental del suelo subyacente ni en la MAOM. Esto se asoció con una reducción de la fijación biológica neta de N bajo el efecto combinado del aumento de la temperatura y la sequía, destacando cómo las condiciones climáticas cambiantes disminuyen algunas de las funciones ecosistémicas más fundamentales de las biocostras, con repercusiones perjudiciales para el ciclo de C y N y la persistencia de los depósitos de MOS en los ecosistemas áridos.

• Klíčová slova
• C cycle, PLFA, biocrust, biological soil crusts, climate change, dryland, dual labeling, soil organic matter,
• MeSH
• atmosféra * chemie   MeSH
• dusík metabolismus   analýza   MeSH
• ekosystém MeSH
• klimatické změny * MeSH
• koloběh dusíku * MeSH
• koloběh uhlíku * MeSH
• období sucha * MeSH
• oxid uhličitý metabolismus   analýza   MeSH
• půda * chemie   MeSH
• půdní mikrobiologie * MeSH
• uhlík metabolismus   analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• oxid uhličitý MeSH
• půda * MeSH
• uhlík MeSH

Nitrogen (N) is an essential macronutrient for microalgae, influencing their productivity, composition, and growth dynamics. Despite the dramatic consequences of N starvation, many free-living and endosymbiotic microalgae thrive in N-poor and N-fluctuating environments, giving rise to questions about the existence and nature of their long-term N reserves. Our understanding of these processes requires a unequivocal identification of the N reserves in microalgal cells as well as their turnover kinetics and subcellular localization. Herein, we identified crystalline guanine as the enigmatic large-capacity and rapid-turnover N reserve of microalgae. The identification was unambiguously supported by confocal Raman, fluorescence, and analytical transmission electron microscopies as well as stable isotope labeling. We discovered that the storing capacity for crystalline guanine by the marine dinoflagellate Amphidiniumcarterae was sufficient to support N requirements for several new generations. We determined that N reserves were rapidly accumulated from guanine available in the environment as well as biosynthesized from various N-containing nutrients. Storage of exogenic N in the form of crystalline guanine was found broadly distributed across taxonomically distant groups of microalgae from diverse habitats, from freshwater and marine free-living forms to endosymbiotic microalgae of reef-building corals (Acropora millepora, Euphyllia paraancora). We propose that crystalline guanine is the elusive N depot that mitigates the negative consequences of episodic N shortage. Guanine (C5H5N5O) may act similarly to cyanophycin (C10H19N5O5) granules in cyanobacteria. Considering the phytoplankton nitrogen pool size and dynamics, guanine is proposed to be an important storage form participating in the global N cycle.

• Klíčová slova
• coral, guanine, nitrogen cycle, nutrient storage, phytoplankton,
• MeSH
• Dinoflagellata chemie   metabolismus   MeSH
• dusík metabolismus   MeSH
• ekosystém MeSH
• guanin chemie   metabolismus   MeSH
• kinetika MeSH
• korálnatci MeSH
• krystalizace MeSH
• mikrořasy chemie   metabolismus   MeSH
• nelineární optická mikroskopie metody   MeSH
• symbióza MeSH
• transmisní elektronová mikroskopie MeSH
• tropické klima MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• audiovizuální média MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Arktida MeSH
• Názvy látek
• dusík MeSH
• guanin MeSH

Crocosphaera watsonii (hereafter referred to as Crocosphaera) is a key nitrogen (N) fixer in the ocean, but its ability to consume combined-N sources is still unclear. Using in situ microcosm incubations with an ecological model, we show that Crocosphaera has high competitive capability both under low and moderately high combined-N concentrations. In field incubations, Crocosphaera accounted for the highest consumption of ammonium and nitrate, followed by picoeukaryotes. The model analysis shows that cells have a high ammonium uptake rate (~7 mol N [mol N]-1 d-1 at the maximum), which allows them to compete against picoeukaryotes and nondiazotrophic cyanobacteria when combined N is sufficiently available. Even when combined N is depleted, their capability of nitrogen fixation allows higher growth rates compared to potential competitors. These results suggest the high fitness of Crocosphaera in combined-N limiting, oligotrophic oceans heightening its potential significance in its ecosystem and in biogeochemical cycling. IMPORTANCE Crocosphaera watsonii is as a key nitrogen (N) supplier in marine ecosystems, and it has been estimated to contribute up to half of oceanic N2 fixation. Conversely, a recent study reported that Crocosphaera can assimilate combined N and proposed that unicellular diazotrophs can be competitors with non-N2 fixing phytoplankton for combined N. Despite its importance in nitrogen cycling, the methods by which Crocosphaera compete are not currently fully understood. Here, we present a new role of Crocosphaera as a combined-N consumer: a competitor against nondiazotrophic phytoplankton for combined N. In this study, we combined in situ microcosm experiments and an ecosystem model to quantitatively evaluate the combined-N consumption by Crocosphaera and other non-N2 fixing phytoplankton. Our results suggest the high fitness of Crocosphaera in combined-N limiting, oligotrophic oceans and, thus, heightens its potential significance in its ecosystem and in biogeochemical cycling.

• Klíčová slova
• Crocosphaera watsonii, combined nitrogen, ecological model, marine N2 fixer,
• MeSH
• amoniové sloučeniny * MeSH
• dusík MeSH
• ekosystém MeSH
• mořská voda MeSH
• sinice * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amoniové sloučeniny * MeSH
• dusík MeSH

Environmental conditions to which plants acclimate prior exposure to abiotic or biotic stressors can greatly affect their subsequent resilience. This may have a significant impact on the response to ongoing climate change and can be useful for increasing the food security under adverse weather conditions associated with climate change.Within this study, we tested the hypothesis that plant morphological and biochemical acclimation to radiation conditions and nitrogen (N) availability is closely linked with carbon (C) and N balance. Four barley (Hordeum vulgare) varieties, differing in their morphological characteristics and sensitivity to photooxidative stress, were grown at two levels of N supply and four radiation regimes combining distinct levels of ultraviolet (UV) and photosynthetically active radiation (PAR). Changes in root and shoot morphology, accumulation of phenolic compounds, amino acids, and sugars were studied together with the analysis of C and N content in leaves. Both UV and PAR reduced leaf length and increased root-to-shoot ratio (R:S). Such effect was more pronounced under high N availability. High N supply reduced R:S, but this effect showed significant interactions with UV and PAR, and also with barley variety. Changes in R:S were positively related to C:N ratio in leaves that varied in response to both N availability and radiation treatments. UV radiation, particularly in combination with high PAR intensity, led to increases in most phenolic compounds (particularly flavones such as saponarin, homoorientin and isovitexin) which was also closely associated with changes in C:N ratio, while specifically phenolic acids (vanillic and syringic acids) decreased under high levels of UV and PAR, and hydroxycinnamic acids responded positively mainly to PAR. Although high N availability generally reduced the accumulation of phenolic compounds, this effect was genotype-specific and modulated by the radiation regime. A similar antagonistic effect of radiation treatment and N availability was also found for the accumulation of sugars (pentoses), resulting in a close relationship between the accumulation of pentoses and C:N ratio. The accumulation of most amino acids, in contrary to phenolic compounds, increases at high N and is also stimulated by high PAR and UV intensities. We conclude that radiation conditions and N availability have opposite effects on plant morphology and accumulation of most phenolic compounds and modulate the amino acid and sugar metabolism. Strong associations of these responses with changes in C:N ratio indicates that plant stoichiometry integrates acclimation processes and induction of relevant defence mechanisms.

• Klíčová slova
• Amino acids, Barley, Carbon, Nitrogen, Phenolic compounds, Root to shoot ratio, Sugars,
• MeSH
• dusík MeSH
• fotosyntéza MeSH
• ječmen (rod) * MeSH
• listy rostlin MeSH
• rostliny MeSH
• ultrafialové záření MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH

Understorey communities can dominate forest plant diversity and strongly affect forest ecosystem structure and function. Understoreys often respond sensitively but inconsistently to drivers of ecological change, including nitrogen (N) deposition. Nitrogen deposition effects, reflected in the concept of critical loads, vary greatly not only among species and guilds, but also among forest types. Here, we characterize such context dependency as driven by differences in the amounts and forms of deposited N, cumulative deposition, the filtering of N by overstoreys, and available plant species pools. Nitrogen effects on understorey trajectories can also vary due to differences in surrounding landscape conditions; ambient browsing pressure; soils and geology; other environmental factors controlling plant growth; and, historical and current disturbance/management regimes. The number of these factors and their potentially complex interactions complicate our efforts to make simple predictions about how N deposition affects forest understoreys. We review the literature to examine evidence for context dependency in N deposition effects on forest understoreys. We also use data from 1814 European temperate forest plots to test the ability of multi-level models to characterize context-dependent understorey responses across sites that differ in levels of N deposition, community composition, local conditions and management history. This analysis demonstrated that historical management, and plot location on light and pH-fertility gradients, significantly affect how understorey communities respond to N deposition. We conclude that species' and communities' responses to N deposition, and thus the determination of critical loads, vary greatly depending on environmental contexts. This complicates our efforts to predict how N deposition will affect forest understoreys and thus how best to conserve and restore understorey biodiversity. To reduce uncertainty and incorporate context dependency in critical load setting, we should assemble data on underlying environmental conditions, conduct globally distributed field experiments, and analyse a wider range of habitat types.

• Klíčová slova
• Biodiversity, Critical load, Herb layer, N deposition, forestREplot,
• MeSH
• biodiverzita MeSH
• dusík analýza   MeSH
• ekosystém MeSH
• koloběh dusíku MeSH
• lesy * MeSH
• půda MeSH
• rostliny MeSH
• stromy růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• dusík MeSH
• půda MeSH