185 research outputs found

    Controlling weeds with natural phytotoxic Substances (NPS) in direct seeded soybean

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    Field trials on weed control in direct seeding with the use of natural phytotoxic ingredients (NPI) were carried out from 2011 to 2013 at the Agricultural Research Institute of Paraná state, Brazil (IAPAR). Soybean was direct seeded into residues of precrop black oats (\textit{Avena strigosa)}. In a split-plot trial the whole-plot treatment consisted of two different weed densities. In the eight subplot treatments the effects of "natural phytotoxic ingredients" (NPI) on weed control was evaluated. The two NPI formulations used in the experiment contained 50 L/ha Pine Oil (formulation ``Pine Oil'') or 50 L/ha d-Limonene (formulation ``Limonene''), both combined with 50 kg/ha NaCl. These formulations were applied once, twice, or three times in a weekly interval. A weedy and a manually hoed clean plot was used as control treatment. The single application treatments of Limonene and Pine Oil scored 41 \% and 52 \%, two applications 53 \% and 56 \% and three applications 61 \% and 67 \% respectively, with a 70 \% rating being considered an acceptable result in conventional herbicide testing. The grain yield for the 'clean' control treatment was highest with 4.07 t/ha and lowest for the untreated control treatment with 2.61 t/ha. The limonene treatments yielded 3.07, 3.22, 3.57, and the pine oil treatments 2.68, 3.00 and 2.96 t/ha with one, two and three applications respectively. The lower grain yields of pine oil despite slightly better performance in the weed control rating can be explained by phytotoxic effects of applied product which came in contact with soybean crop during application

    Lattice Calculation of Glueball Matrix Elements

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    Matrix elements of the form are calculated using the lattice QCD Monte Carlo method. Here, ∣G>|G> is a glueball state with quantum numbers 0++ 0^{++}, 2++ 2^{++}, 0−+ 0^{-+} and GG is the gluon field strength operator. The matrix elements are obtained from the hybrid correlation functions of the fuzzy and plaquette operators performed on the 12412^{4} and 14414^{4} lattices at β=5.9\beta = 5.9 and 5.965.96 respectively. These matrix elements are compared with those from the QCD sum rules and the tensor meson dominance model. They are the non-perturbative matrix elements needed in the calculation of the partial widths of J/ΨJ/\Psi radiative decays into glueballs.Comment: 12 pages, UK/92-0

    The carbonic anhydrase of Clostridium autoethanogenum represents a new subclass of β-carbonic anhydrases

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    Carbonic anhydrase catalyses the interconversion of carbon dioxide and water to bicarbonate and protons. It was unknown if the industrial relevant acetogen Clostridium autoethanogenum possesses these enzymes. We identified two putative carbonic anhydrase genes in its genome, one of the β class and one of the γ class. Carbonic anhydrase activity was found for the purified β class enzyme, but not the γ class candidate. Functional complementation of an Escherichia coli carbonic anhydrase knock-out mutant showed that the β class carbonic anhydrase could complement this activity, but not the γ class candidate gene. Phylogenetic analysis showed that the β class carbonic anhydrase of Clostridium autoethanogenum represents a novel sub-class of β class carbonic anhydrases that form the F-clade. The members of this clade have the shortest primary structure of any known carbonic anhydrase

    Correlation between lasing and transport properties in a quantum dot-resonator system

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    We study a double quantum dot system coherently coupled to an electromagnetic resonator. By suitably biasing the system, a population inversion can be created between the dot levels. The resulting lasing state exists within a narrow resonance window, where the transport current correlates with the lasing state. It allows probing the lasing state via a current measurement. Moreover, the resulting narrow current peak opens perspective for applications of the setup for high resolution measurements.Comment: 4 pages, 4 figures; submitted to "Journal of Physics: Conference Series

    Context-Aware UPnP-AV Services for Adaptive Home Multimedia Systems

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    Recommended by Harald Kosch One possibility to provide mobile multimedia in domestic multimedia systems is the use of Universal Plug and Play Audio Visual (UPnP-AV) devices. In a standard UPnP-AV scenario, multimedia content provided by a Media Server device is streamed to Media Renderer devices by the initiation of a Control Point. However, there is no provisioning of context-aware multimedia content customization. This paper presents an enhancement of standard UPnP-AV services for home multimedia environments regarding context awareness. It comes up with context profile definitions, shows how this context information can be queried from the Media Renderers, and illustrates how a Control Point can use this information to tailor a media stream from the Media Server to one or more Media Renderers. Moreover, since a standard Control Point implementation only queries one Media Server at a time, there is no global view on the content of all Media Servers in the UPnP-AV network. This paper also presents an approach of multimedia content integration on the Media Server side that provides fast search for content on the network. Finally, a number of performance measurements show the overhead costs of our enhancements to UPnP-AV in order to achieve the benefits

    A novel conjugal donor strain for improved DNA transfer into Clostridium spp.

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    © 2019 The Authors Importance: The ability to transfer genetic material into a target organism is crucial for the development of a wide range of targeted genetic manipulation techniques. Overcoming the organisms’ native restriction systems which target foreign incoming DNA is one strategy that can increase the efficiency of genetic transfer. The novel E. coli donor strain described here employs this strategy, increasing the frequencies of conjugation into a range of clostridial strains, and therefore opening up the potential to implement novel gene manipulation techniques. Furthermore this novel donor strain has potential applications across a wide range of genetically recalcitrant organisms, and should be beneficial wherever the frequently occurring Type IV restriction systems are possessed by the target in question

    Metabolic engineering of Clostridium autoethanogenum for selective alcohol production

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    Gas fermentation using acetogenic bacteria such as Clostridium autoethanogenum offers an attractive route for production of fuel ethanol from industrial waste gases. Acetate reduction to acetaldehyde and further to ethanol via an aldehyde: ferredoxin oxidoreductase (AOR) and alcohol dehydrogenase has been postulated alongside the classic pathway of ethanol formation via a bi-functional aldehyde/alcohol dehydrogenase (AdhE). Here we demonstrate that AOR is critical to ethanol formation in acetogens and inactivation of AdhE led to consistently enhanced autotrophic ethanol production (up to 180%). Using ClosTron and allelic exchange mutagenesis, which was demonstrated for the first time in an acetogen, we generated single mutants as well as double mutants for both aor and adhE isoforms to confirm the role of each gene. The aor1+2 double knockout strain lost the ability to convert exogenous acetate, propionate and butyrate into the corresponding alcohols, further highlighting the role of these enzymes in catalyzing the thermodynamically unfavourable reduction of carboxylic acids into alcohols

    Systems-level engineering and characterization of Clostridium autoethanogenum through heterologous production of poly-3-hydroxybutyrate (PHB)

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    Gas fermentation is emerging as an economically attractive option for the sustainable production of fuels and chemicals from gaseous waste feedstocks. Clostridium autoethanogenum can use CO and/or CO + H as its sole carbon and energy sources. Fermentation of C. autoethanogenum is currently being deployed on a commercial scale for ethanol production. Expanding the product spectrum of acetogens will enhance the economics of gas fermentation. To achieve efficient heterologous product synthesis, limitations in redox and energy metabolism must be overcome. Here, we engineered and characterised at a systems-level, a recombinant poly-3-hydroxybutyrate (PHB)-producing strain of C. autoethanogenum. Cells were grown in CO-limited steady-state chemostats on two gas mixtures, one resembling syngas (20% H) and the other steel mill off-gas (2% H). Results were characterized using metabolomics and transcriptomics, and then integrated using a genome-scale metabolic model reconstruction. PHB-producing cells had an increased expression of the Rnf complex, suggesting energy limitations for heterologous production. Subsequent optimization of the bioprocess led to a 12-fold increase in the cellular PHB content. The data suggest that the cellular redox state, rather than the acetyl-CoA pool, was limiting PHB production. Integration of the data into the genome-scale metabolic model showed that ATP availability limits PHB production. Altogether, the data presented here advances the fundamental understanding of heterologous product synthesis in gas-fermenting acetogens
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