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Nitric oxide (NO) is an important signalling molecule that is involved in many different physiological processes in plants. Here, we report about a NO-fixing mechanism in Arabidopsis, which allows the fixation of atmospheric NO into nitrogen metabolism. We fumigated Arabidopsis plants cultivated in soil or as hydroponic cultures during the whole growing period with up to 3 ppmv of NO gas. Transcriptomic, proteomic and metabolomic analyses were used to identify non-symbiotic haemoglobin proteins as key components of the NO-fixing process. Overexpressing non-symbiotic haemoglobin 1 or 2 genes resulted in fourfold higher nitrate levels in these plants compared with NO-treated wild-type. Correspondingly, rosettes size and weight, vegetative shoot thickness and seed yield were 25, 40, 30, and 50% higher, respectively, than in wild-type plants. Fumigation with 250 ppbv 15NO confirmed the importance of non-symbiotic haemoglobin 1 and 2 for the NO-fixation pathway, and we calculated a daily uptake for non-symbiotic haemoglobin 2 overexpressing plants of 250 mg N/kg dry weight. This mechanism is probably important under conditions with limited N supply via the soil. Moreover, the plant-based NO uptake lowers the concentration of insanitary atmospheric NOx, and in this context, NO-fixation can be beneficial to air quality.

This study aimed to understand the molecular mechanisms of nitrogen dioxide (NO2)-induced toxicity and cell death in plants. Exposure of Arabidopsis to high concentrations of NO2 induced cell death in a dose-dependent manner. No leaf symptoms were visible after fumigation for 1 h with 10 parts per million (ppm) NO2. However, 20 ppm NO2 caused necrotic lesion formation and 30 ppm NO2 complete leaf collapse, which had already started during the 1 h fumigation period. NO2 fumigation resulted in a massive accumulation of nitrite and in protein modifications by S-nitrosylation and tyrosine nitration. Nitric oxide (NO) at 30 ppm did not trigger leaf damage or any of the effects observed after NO2 fumigation. The onset of NO2-induced cell death correlated with NO and hydrogen peroxide (H2O2) signaling and a decrease in antioxidants. NO- and H2O2-accumulating mutants were more sensitive to NO2 than wild-type plants. Accordingly, experiments with specific scavengers confirmed that NO and H2O2 are essential promoters of NO2-induced cell death. Leaf injection of 100 mM nitrite caused an increase in S-nitrosylation, NO, H2O2, and cell death suggesting that nitrite functioned as a mediator of NO2-induced effects. A targeted screening of phytohormone mutants revealed a protective role of salicylic acid (SA) signaling in response to NO2. It was also shown that phytohormones were modulators rather than inducers of NO2-induced cell death. The established experimental set-up is a suitable system to investigate NO2 and cell death signaling in large-scale mutant screens.

Dear Sir, We were interested to read the article by Critchell et al. [1] highlighting concerns about the accuracy of bedside capillary blood glucose measurements in critically ill patients. We would agree that the importance of sampling site for blood glucose measurement has been under-emphasized in the published studies on hyperglycaemia and tight glycaemic control. The majority of studies linking hyperglycaemia with adverse clinical outcome have not provided data on the site of sampling. We would like to share preliminary data regarding the use of central venous blood sampling for glucose measurement in critically ill children. The objective of this preliminary study was to compare blood glucose concentrations in simultaneously drawn arterial and central venous blood glucose samples taken for clinical purposes. Paired arterial and central venous blood gas samples were taken to obtain information about oxygen extraction and the results were prospectively documented. Blood glucose was measured on a blood gas analyzer (Bayer Rapidlab; electrochemical biosensor), which is subject to strict quality control by the Clinical Chemistry department. No glucose containing solution was infused into either the arterial or the central venous sampling lines. A total of 245 paired arterial and central venous blood samples were obtained from 71 children, age range 5 days–14 years, between January and October 2006. The majority of cases were children post cardiac surgery, reflecting a group of patients in whom regular assessment of oxygen extraction is undertaken. The median number of samples per patient was 2 (range 1–22). The samples included a wide range of arterial blood glucose values, from 2.4 to 23 mmol/l. There was poor agreement between arterial and central venous blood glucose (Fig. 1). The central venous blood glucose was frequently higher than the arterial blood glucose (median 0.4 mmol/l, CI 0.3–0.5, P \ 0.001 Wilcoxon Signed Rank test). On occasions, the difference exceeded 5 mmol/l. The implications of these findings for titration of insulin therapy are obvious. Inappropriate adjustments to insulin therapy could be made and, importantly, hypoglycaemia could go undetected if central venous sampling is used to monitor blood glucose in this population of critically ill children. It is common for a child to be managed without an arterial line once their cardio-respiratory condition has stabilized, and for bloods to be taken through a central line, if present, to avoid the need for venepuncture. In contrast with our findings, a recent study by Evron et al. [2] found no difference between arterial and central venous blood glucose concentration in adult patients undergoing major orthopaedic or colon surgery though these patients were all studied in the context of general anaesthesia and surgery and were not critically ill. It is possible that glucose containing fluids infused into a vein peripheral to the central venous line or infused via one of the other central venous line lumens could have contaminated the central venous sample that was taken. As this was an opportunistic study performed under uncontrolled conditions information about glucose infusions was not collected, other than confirmation that no glucose containing fluid was infused into either the arterial or central venous sampling lines. However, alternative explanations are possible in that glucose may be generated in peripheral tissues, most notably in muscle, during critical illness and released into the venous system [3, 4]. 0 5 10 15 20 25

A continuous labelling experiment using 13C-CO2 was set up in open-top chambers in order to follow fluxes of assimilates from the plant into the rhizosphere. Labelling was performed for one growing season by adding low amounts of CO2 depleted in 13C to the atmosphere of the open-top chambers, resulting in a difference of ∆ 13C 5‰ V-PDB compared to ambient conditions. The label was recovered in both plant parts and soil microbial communities, analysed via phospholipid fatty acid (PLFA) side chains. PLFA 18:2ω6,9 showed a significant incorporation of the 13C label in October, indicating that fungi utilized plant derived carbon. In bacterial PLFA no label incorporation was detected, probably due to a lower use of rhizodeposits or a preference to older carbon compounds as energy sources. This experimental setup represents a low-cost continuous labelling method for field experiments with only minor increase of CO2 concentrations.

An experiment, focusing on the effects of chronically enhanced O3 regimes on young beech (Fagus sylvatica) and on the microbial rhizosphere community structure, was conducted from November 2002 to August 2006 in eight field lysimeters at the Helmholtz Zentrum Munchen. The instrumentations of the lysimeters enabled the establishment of the water balance in the unsaturated zone and the assessment of the water uptake by plants. Further, the containment provided by the lysimeters made it possible to apply a root rot pathogen infection without contaminating the surrounding soil. A free-air fumigation system allowed to double the O3 concentration in the air above four lysimeters relative to the ambient air. To avoid damage of the leaves the maximum O3 concentration was limited to 150 nL L−1. For nearly 70% of the time the set-point concentration was reached within 10%. In the final harvest the whole soil column was retrieved and a nearly complete data-set of above-ground and below-ground parameters became available.

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant–soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003–2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is remarkably consistent, further underlining the phytotoxic potential of elevated tropospheric ozone levels.

In der letzten Mitteilung uber Ergebnisse des IOSDV‐Standortes Limburgerhof mit der Fruchtfolge ‘Kornermais‐Winterweizen‐Wintergerste’ werden Auswirkungen von organischer und mineralischer N‐Dungung im Zeitraum 1987–1995 incl. Nachwirkung im Jahr 1996 dargelegt. Dabei hat sich gezeigt: 1. Die Differenzierung des N‐Angebotes durch verschieden hohe Winterniederschlage hat den N‐Entzug durch die Kornertrage deutlich, den durch Stroh dagegen kaum beeinflust. 2. Zur Ertragssicherheit beitragend, wird nach feuchtem Winterverlauf eine hohere mineralische N‐Gabe besser verwertet als nach trockenem. 3. Bei einem N‐Angebot aus mineralischer und zusatzlicher organischer Dungung setzen die angebauten Kulturen insgesamt mehr Stickstoff in Ertrag und Qualitat um als bei fehlender organischer Dungung. 4. Die Ct und Nt‐Bodenwerte haben sich im Versuchszeitraum mit zunehmender N‐Dungung sowie bei zusatzlicher organischer Dungung erhoht. Die erreichte Differenzierung der Ertragsfahigkeit beim Vergleich der Dungungsvariante...

In einer zweiten Mitteilung uber Ergebnisse des IOSDV‐Standortes Limburgerhof werden Auswirkungen von organischer und mineralischer N‐Dungung im Zeitraum 1987–1995 und der Fruchtfolge ‘Kornermais—Winterweizen—Wintergerste’ dargelegt auf: a) Verlaufe von Nmin(NO3‐N/NH4‐N) und Norg b) Stickstoff‐Verlagerung in Abhangigkeit von Herbst‐ und Winterniederschlag sowie Zwischenfruchtbau und c) Folgewirkungen auf Kornertrag und N‐Entzug Im einzelnen hat sich ergeben: 1. Der Einflus der Dungungsvarianten differenziert sich in den NO3‐N‐Werten Ende Winter (unter Wintergetreide) bzw. Anfang Fruhjahr (vor Kornermais) am relativ schwachsten im Vergleich zu den Terminen ‘nach der Ernte’ und vor allem ‘ Anfang Winter’. 2. Im Mittel von 4 winterfeuchten Jahren (Dezember—Februar: 135 mm) nimmt NO3‐N im Terminvergleich Vor‐ zu Nachwinter um ca. 70% ab gegenuber etwa 25% im Mittel von 4 wintertrockenen Jahren (Dezember—Februar: 70 mm). 3. Mit Zwischenfruchtbau gelingt eine effiziente Reduktion der Nmin‐Werte durch biologisch...

Es werden Ertragsreaktionen von verschiedenen landwirtschaftlichen Kulturen aus zwei N‐P‐K‐Nahr‐stoffmangel‐Dauerfeldversuchen vornehmlich fur den Zeitraum 1970–1996 dargestellt. Die 40 bzw. 60 Jahre alten Dauerfeldversuche liegen auf zwei bodenmasig verschiedenen, aber klimatisch einheitlichen Standorten. 1. Im 60‐jahrigen Dauerfeldversuch Limburgerhof mit u. a. relativ schwachem Humusgehalt, durchlassiger Krume der Bodenart lehmiger Sand und einem sehr gunstigen Phosphat‐Nachlieferungsvermogen zeigen sich folgende Ergebnisse: 1.1 Beim Bewirtschaftungssystem‐Vergleich ‘viehhaltend ‐ viehlos’ steigert die Stallmistgabe den Ertrag von Zuckerruben und Kartoffeln am starksten in den Varianten ‘ohne N’. Bei Kornermais nach Zuckerruben fuhrt Rubenblatt im Trend zu hoheren Ertragen als die Nachwirkung von Stallmist zur Vorfrucht. 1.2 Die PK‐Variante liegt im gesamten Versuchszeitraum ertraglich nur unwesentlich uber ungedungt. 1.3 Die NPK‐ und NK‐Varianten (ohne P) liegen im Mittel der Bewirtschaftungssysteme b...

OBJECTIVE To canvass the current opinion of pediatric intensivists in the United Kingdom regarding the importance of hyperglycemia,their approach to management, and their views in relation to a potential intervention trial of tight glycemic control. DESIGN Electronic survey comprising a 17-point questionnaire,along with six clinical scenarios describing cases of bronchiolitis, septic shock, major trauma, postcardiac surgery, necrotizing enterocolitis,and acute respiratory distress syndrome. SETTING All pediatric intensive care units in the United Kingdom(n = 21). PARTICIPANTS All consultant pediatric intensivists in the United Kingdom (n = 117). INTERVENTIONS None. MEASUREMENTS AND METHODS The response rate was 75% (88 of 117), representing all 21 units. Although all respondents administer insulin to hyperglycemic patients, only one in two believe hyperglycemia causes significant morbidity in critically ill children. Predominant factors influencing the decision to start insulin are severity of hyperglycemia (95% of responders), duration of hyperglycemia (85%), and patient diagnosis (49%). The blood glucose threshold for starting insulin varied widely from 6.1 to>15 mmol x L(-1) (110-270 mg x dL(-1)) for each of the six scenarios,with poor agreement between intensivists within each center(intraclass correlation coefficient of 0.29). Sixty-seven percent of respondents, representing 14 of the 21 units reported having no written policy or guideline in their unit for management of hyper-glycemia in nondiabetic children. Eighty-six percent (76) of intensivists would be prepared to participate in a trial of "tight glycemic control" but only 63% (55) would be prepared to include all patient groups. Only 20% would be willing to target blood glucose below 6.1 mmol x L(-1) (110 mg x dL(-1)) in the tight control group. CONCLUSIONS This survey suggests significant variation in the management of hyperglycemia across the UK Practice varies even among intensivists from the same unit, reflecting the fact that few units have 'an agreed written guidance in place.' The majority of intensivists would be prepared to participate in a trial of tight glycemic control.

Numerical flow simulations with common hydraulic conductivity/depth distributions result in an active and passive turn-over zone, both occurring world wide. Geochemical modeling of uranium species distribution under oxidizing conditions in carbonate and sulfate waters mostly yields negatively charged or neutral UO2-carbonate complexes, which do not sorbe on negatively charged mineral surfaces (pH 5 to 8), which is in good agreement with batch experiments. Contrary, in crystalline aquifers Uranium species are mostly positively charged, favoring sorption. Dilution in the passive turn-over zone is dominated by transverse hydro-dynamic dispersion and gets enhanced by orders of magnitudes in bi-porous sediments through matrix diffusion. At the transition from the passive into the active turn-over zone dilution gets further enhanced.

Fabrication and characteristics of InGaAs/InGaAlAs separate confinement heterostructure multiquantum-well (SCH-MOW) metal-clad ridge-waveguide (MCRW) laser diodes are reported. The layer structures have been grown by atmospheric pressure metalorganic vapor phase epitaxy (AP-MOVPE) without any use of phospine. The lasers emit around 1585 nm, and the minimum cw-threshold current is 15 mA for 200 µm-long lasers with high-reflection (HR) coating on both mirrors. For 600 µm- and 800 µm-long one-side HR-coated devices, continuous wave (CW) output power levels up to 16 mW and CW operation around 60°C have been achieved. A power-limited 3 dB bandwidth of 5.1 GHz has been measured. From small signal modulation measurements, a maximum differential gain of 7.7×10-16 cm2 has been calculated.

Die Frage, warum sich fur verschiedene Hohen einer Membran verschiedene osmotische Drucke berechnen lassen, wurde beantwortet. Es wurde ein Einblick in die Vorgange gewonnen, die sich bei der Einstellung des Gleichgewichtes in verschiedenen Hohen abspielen, und eine tiefere Begrundung fur die Formel gegeben, nach der man den Uberdruck in der Membranmitte dem osmotischen Druck der Ausgangslosung gleichsetzt. Es wurde gezeigt, das sich ein Sedimentationsgleichgewicht durch horizontalen Stofftransport durch eine Membran ausbilden kann. Dieser Vorgang kann unter Umstanden zur Untersuchung von Sedimentationsgleichgewichten hochmolekularer einheitlicher Substanzen im normalen Schwerefeld dienen. Eine Reihe von Fragen, besonders quantitativer Art, bedarf noch der Bearbeitung.

In Analogie zu den Destillations- bzw. Dampflinien der einfachen Destillation werden Rektifikations- bzw. Destillatlinien definiert, welche die Anderung der Zusammensetzung des Destillationsruckstandes (Blaseninhalts) bzw. des Destillats wahrend der Rektifikation homogener Dreistoffgemische angeben. Die Diskussion der Differentialgleichung der Rektifikationslinien fur die Umgebung der Eckpunkte des Darstellungsdreiecks und der binaren azeotropen Punkte erlaubt die Aufstellung allgemeiner Gesetze, denen die Rektifikationslinienscharen gehorchen. Auf diese Weise last sich aus dem Destillationslinienfeld der Charakter des zugehorigen Rektifikationslinienfeldes fur ein gegebenes Rucklaufverhaltnis und eine gegebene Bodenzahl ableiten. Mit den Rektifikationsdiagrammen lassen sich alle Experimente deuten, die mit wirksamen Kolonnen an z. T. komplizierten Dreistoffgemischen durchgefuhrt worden sind. Das zeitweilige Sinken der Siedetemperatur des Destillats und andere Erscheinungen, fur die es kein Analogon bei Zweistoffgemischen gibt, werden im Rahmen der vorliegenden Theorie verstandlich. Eigene Rektifikationsversuche an dem System Methanol-Aceton-Chloroform bestatigen die Richtigkeit der behaupteten Zusammenhange.

Das osmotische Gleichgewicht in verschiedenen Höhen ist mit dem Sedimentationsgleichgewicht eng gekoppelt. Der osmotische Druck hängt von der Höhe ab. Er ist durch diese Abhängigkeit auf die Zustandsgrößen bezogen, die im Sedimentationsgleichgewicht in der betrachteten Höhe vorliegen.