1‐deoxy‐d‐xylulose 5‐phosphate serves as a precursor for the biosynthesis of the vitamins thiamine and pyridoxal and for the formation of isopentenyl pyrophosphate and dimethylallyl pyrophosphate via ...the nonmevalonate pathway of terpenoid biosynthesis. Earlier studies had shown that Escherichia coli incorporates unphosphorylated 1‐deoxy‐d‐xylulose into the terpenoid side chain of ubiquinones with high efficacy. We show that d‐xylulokinase of E. coli (EC 2.7.1.17) catalyzes the phosphorylation of 1‐deoxy‐d‐xylulose at the hydroxy group of C‐5 at a rate of 1.6 µmol·mg min−1. This reaction constitutes a potential salvage pathway for the generation of 1‐deoxy‐d‐xylulose 5‐phosphate from exogenous or endogenous 1‐deoxy‐d‐xylulose as starting material for the biosynthesis of terpenoids, thiamine and pyridoxal.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Cultivation of Scots pine (Pinus sylvestris L.) seedlings under simulated global radiation including the UV-B band (280-320 nm; 220 mW m^sup -2^ UV-B^sub BE^) led to increased formation of the ...diacylated flavonol glucosides 3'',6''-di-p-coumaroyl-astragalin and 3'',6''-di-p-coumaroyl-isoquercitrin in primary and cotyledonary needles, respectively. 3'',6''-Di-p-coumaroyl-astragalin was also the main constitutive diacylated flavonol glucoside in both needle types. This compound predominantly accumulated in primary needles upon UV-B irradiation, and reached concentrations of 2.4 μmol g^sup -1^ fresh weight (fw). Its concentration was only weakly affected in cotyledonary needles. 3'',6''-Di-p-coumaroyl-isoquercitrin was mainly induced in cotyledonary needles with maximum concentrations of 0.8 to 0.9 μmol g^sup -1^ fw, but was virtually unaffected in primary needles under the same irradiation conditions. Pulse labelling with L-(U-^sup 14^C)phenylalanine revealed that these metabolites were formed de novo. Phenylalanine ammonia-lyase (EC 4.3.1.5) and chalcone synthase (EC 2.3.1.74) were only slightly induced by the UV-B treatment. The results described here represent the first report on UV-B-induced flavonoid biosynthesis in a conifer species.PUBLICATION ABSTRACT
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In a closed aerated laboratory system super(14)C-monochlorobenzene ( super(14)C-MCB) was incubated with sieved soil, amended with different substrates, to investigate the behavior of this compound in ...an arable soil. The volatilized super(14)C-compounds and super(14)CO sub(2) were trapped separately thus allowing a clear differentiation between volatilization and mineralization of MCB. At the end of the experiment extractable and non-extractable residues were determined and a super(14)C-mass balance was established. The results show clearly, that volatilization is the main loss mechanism of MCB from soils whereas mineralization is of minor importance. Additional nutrition sources could not increase the mineralization process.
Es werden Prognosemodelle zur Abschaetzung der Baumvitalitaet nach Befall durch den Schwammspinner (Lymantria dispar) in Eichenmischwaeldern (Quercus spp.) praesentiert. Diese Modelle unterscheiden ...von frueheren Ansaetzen dadurch, dass in den Analysen der Blattverlust beruecksichtigt wird. In der kategorialen Varianzanalyse fuer die Mortalitaet zeigten die folgenden Parameter einen hochsignifikanten Einfluss: Intensitaet des Blattverlustes, Kronenzustand vor dem Befall (Kronenvitalitaet), soziale Stellung und Artenzusammensetzung des Bestandes. Schwere Blattverluste waren stark und gleichmaessig mit der zunehmenden Wahrscheinlichkeit des Absterbens korreliert. Zur Entwicklung von praxistauglichen Prognosemodellen fuer die Baummortalitaet wurde die CART-Analyse, ein binominales Entscheidungsverfahren, verwendet. Das beste Modell umfasste 65 Risikogruppen und klassifizierte 75% der lebenden und 76% der abgestorbenen Baeume korrekt. Die Modelle wurden separat auf die verschiedenen Blattverlustklassen angewendet und lieferten fuer 63-78% der Baeume korrekte Klassifikationen. Diese Modelle koennen in der Praxis zur Vorhersage des Mortalitaetsrisikos nach mittleren und schweren Blattverlusten eingesetzt werden. Ausserdem kann damit die prognostizierte Mortalitaet mit der Mortalitaet von nicht befallenen Baeumen verglichen und so die Auswirkung eines L. dispar-Befalles auf die Bestaende bestimmt werden. Aufgrund der Mortalitaetswahrscheinlichkeiten in Abhaengigkeit vom Blattverlust koennen bereits vor einem Befall Richtlinien fuer die waldbauliche Behandlung entwickelt werden, um die Auswirkungen einer L. dispar-Kalamitaet zu minimieren.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Gravitational-wave astronomy has revolutionized humanity's view of the universe, a revolution driven by observations that no other field can make. This white paper describes an observatory that ...builds on decades of investment by the National Science Foundation and that will drive discovery for decades to come: Cosmic Explorer. Major discoveries in astronomy are driven by three related improvements: better sensitivity, higher precision, and opening new observational windows. Cosmic Explorer promises all three and will deliver an order-of-magnitude greater sensitivity than LIGO. Cosmic Explorer will push the gravitational-wave frontier to almost the edge of the observable universe using technologies that have been proven by LIGO during its development. With the unprecedented sensitivity that only a new facility can deliver, Cosmic Explorer will make discoveries that cannot yet be anticipated, especially since gravitational waves are both synergistic with electromagnetic observations and can reach into regions of the universe that electromagnetic observations cannot explore. With Cosmic Explorer, scientists can use the universe as a laboratory to test the laws of physics and study the nature of matter. Cosmic Explorer allows the United States to continue its leading role in gravitational-wave science and the international network of next-generation observatories. With its extraordinary discovery potential, Cosmic Explorer will deliver revolutionary observations across astronomy, physics, and cosmology including: Black Holes and Neutron Stars Throughout Cosmic Time, Multi-Messenger Astrophysics and Dynamics of Dense Matter, New Probes of Extreme Astrophysics, Fundamental Physics and Precision Cosmology, Dark Matter and the Early Universe.
Fifteen collaborating laboratories were sent 9 samples of citrus juice mixtures as blind duplicates for determination of naringin and neohesperidin by liquid chromatography. Two sample pairs were ...100% orange juice and did not contain any naringin or neohesperidin. The remaining 7 sample pairs contained naringin at levels ranging from 3.9 to 46.5 ppm and neohesperidin at levels ranging from 0.14 to 35.6 ppm. Five sample pairs consisted of orange juice mixtures containing 1, 3, and 5% grapefruit juice; 5% sour orange; and 5% K-Early citrus variety. Two sample pairs were orange juice spiked with naringin, neohesperidin, sodium benzoate, and potassium sorbate. Data were received from 13 laboratories. Data from 1 collaborator were eliminated because the method protocol was not followed. Neohesperidin values from another laboratory were also not used because of problems with a coeluting component. Repeatability relative standard deviations ranged from 2.95 to 15.23% for naringin and from 3.00 to 11.74% for neohesperidin. Reproducibility relative standard deviations ranged from 11.34 to 31.94% for naringin and from 10.45 to 26.17% for neohesperidin. The method is reliable for detecting the presence of grapefruit juice in orange juice as indicated by a finding of > or =10 ppm naringin and < or =2 ppm neohesperidin. The method was adopted First Action by AOAC INTERNATIONAL.
A cDNA sequence from Schizosaccharomyces pombe with similarity to 6,7-dimethyl-8-ribityllumazine synthase was expressed in a recombinant Escherichia coli strain. The recombinant protein is a ...homopentamer of 17-kDa subunits with an apparent molecular mass of 87 kDa as determined by sedimentation equilibrium centrifugation (it sediments at an apparent velocity of 5.0 S at 20 degrees C). The protein has been crystallized in space group C2221. The crystals diffract to a resolution of 2.4 A. The enzyme catalyses the formation of 6,7-dimethyl-8-ribityllumazine from 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxy- 2-butanone 4-phosphate. Steady-state kinetic analysis afforded a vmax value of 13 000 nmol.mg-1.h-1 and Km values of 5 and 67 microm for 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate, respectively. The enzyme binds riboflavin with a Kd of 1.2 microm. The fluorescence quantum yield of enzyme-bound riboflavin is < 2% as compared with that of free riboflavin. The protein/riboflavin complex displays an optical transition centered around 530 nm as shown by absorbance and CD spectrometry which may indicate a charge transfer complex. Replacement of tryptophan 27 by tyrosine or phenylalanine had only minor effects on the kinetic properties, but complexes of the mutant proteins did not show the anomalous long wavelength absorbance of the wild-type protein. The replacement of tryptophan 27 by aliphatic amino acids substantially reduced the affinity of the enzyme for riboflavin and for the substrate, 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Enoate reductase (EC) is a protein isolated from Clostridium tyrobutyricum that contains iron, labile sulfide, FAD, and FMN. The enzyme reduces the α,β carbon-carbon double bond of nonactivated ...2-enoates and in a reversible way that of 2-enals at the expense of NADH or reduced methyl viologen. UV-visible and EPR potentiometric titrations detect a semiquinone species in redox intermediate states characterized by an isotropic EPR signal at g = 2.0 without contribution at 580 nm. EPR redox titration shows two widely spread mid-point redox potentials (−190 and −350 mV at pH 7.0), and a nearly stoichiometric amount of this species is detected. The data suggest the semiquinone radical has an anionic nature. In the reduced form, the Fe-S moiety is characterized by a single rhombic EPR spectrum, observed in a wide range of temperatures (4.2-60 K) with g values at 2.013, 1.943, and 1.860 (−180 mV at pH 7.0). The gmax value is low when compared with what has been reported for other iron-sulfur clusters. Mössbauer studies reveal the presence of a 4Fe-4S+2/+1 center. One of the subcomponents of the spectrum shows an unusually large value of quadrupole splitting (ferrous character) in both the oxidized and reduced states. Substrate binding to the reduced enzyme induces subtle changes in the spectroscopic Mössbauer parameters. The Mössbauer data together with known kinetic information suggest the involvement of this iron-sulfur center in the enzyme mechanism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Small, highly absorbing points are randomly present on the surfaces of the main interferometer optics in Advanced LIGO. The resulting nano-meter scale thermo-elastic deformations and substrate lenses ...from these micron-scale absorbers significantly reduces the sensitivity of the interferometer directly though a reduction in the power-recycling gain and indirect interactions with the feedback control system. We review the expected surface deformation from point absorbers and provide a pedagogical description of the impact on power build-up in second generation gravitational wave detectors (dual-recycled Fabry-Perot Michelson interferometers). This analysis predicts that the power-dependent reduction in interferometer performance will significantly degrade maximum stored power by up to 50% and hence, limit GW sensitivity, but suggests system wide corrections that can be implemented in current and future GW detectors. This is particularly pressing given that future GW detectors call for an order of magnitude more stored power than currently used in Advanced LIGO in Observing Run 3. We briefly review strategies to mitigate the effects of point absorbers in current and future GW wave detectors to maximize the success of these enterprises.
While studying amenorrheic runners, the authors became aware of psychiatric differences between them. Psychiatric interviews of 13 amenorrheic and 19 regularly menstruating runners revealed that of ...the amenorrheic runners, 11 reported major affective disorders in themselves or in first- and second-degree relatives and eight reported eating disorders in themselves. Among the regularly menstruating runners, however, there were no eating disorders or major affective disorders, and only one had first-degree relatives with major affective disorders. These data suggest a link between athletic amenorrhea in runners, major affective disorders, and eating disorders.
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