Variation in Molybdenum Content Across Broadly Distributed Populations of Arabidopsis thaliana Is Controlled by a Mitochondrial Molybdenum Transporter (MOT1)

Molybdenum (Mo) is an essential micronutrient for plants, serving as a cofactor for enzymes involved in nitrate assimilation, sulfite detoxification, abscisic acid biosynthesis, and purine degradation. Here we show that natural variation in shoot Mo content across 92 Arabidopsis thaliana accessions is controlled by variation in a mitochondrially localized transporter (Molybdenum Transporter 1 - MOT1) that belongs to the sulfate transporter superfamily. A deletion in the MOT1 promoter is strongly associated with low shoot Mo, occurring in seven of the accessions with the lowest shoot content of Mo. Consistent with the low Mo phenotype, MOT1 expression in low Mo accessions is reduced. Reciprocal grafting experiments demonstrate that the roots of Ler-0 are responsible for the low Mo accumulation in shoot, and GUS localization demonstrates that MOT1 is expressed strongly in the roots. MOT1 contains an N-terminal mitochondrial targeting sequence and expression of MOT1 tagged with GFP in protoplasts and transgenic plants, establishing the mitochondrial localization of this protein. Furthermore, expression of MOT1 specifically enhances Mo accumulation in yeast by 5-fold, consistent with MOT1 functioning as a molybdate transporter. This work provides the first molecular insight into the processes that regulate Mo accumulation in plants and shows that novel loci can be detected by association mapping

Evidence of anaerobic syntrophic acetate oxidation in biogas batch reactors by analysis of ¹³C carbon isotopes

Between 2008 and 2010 various batch experiments were carried out to study the stable carbon isotopic composition of biogas (CH4 and CO2) produced from (i) pure sludge and (ii) sludge including maize. From the evolution of the natural isotopic signature, a temporal change of methanogenic pathways could be detected for the treatment with maize showing that a dominance in acetotrophic methanogenesis was replaced by a mixture of hydrogenotrophic and acetotrophic methanogenesis. For pure sludge, hydrogenotrophic methanogenesis was the dominant or probably exclusive pathway. Experiments with isotopically labelled acetate (99% (CH3COONa)-C-13 and 99% (CH3COONa)-C-13) indicated a significant contribution of syntrophic acetate oxidation (SAO) for all the investigated treatments. In the case of pure sludge, experiments from 2008 showed that acetate was almost entirely oxidised to CO2, i.e. acetotrophic methanogenesis was negligible. However, in 2010, the sludge showed a clear dominance in acetotrophic methanogenesis with a minor contribution by SAO indicating a significant change in the metabolic character. Our results indicate that SAO during anaerobic degradation of maize might be a significant process that needs to be considered in biogas research

Wohnbaulandangebot im laendlichen Raum Fallstudie zu Umfang, Struktur und Inanspruchnahme von Baurechten als Rahmenbedingungen fuer die Siedlungsentwicklung

Bibliothek Weltwirtschaft Kiel C122,358 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Stable carbon isotopes of methane for real- time process monitoring in anaerobic digesters

Efficient operation and stability of biogas plants requires continuous monitoring of the digester content. Traditional laboratory analysis of digester sludge is often complex and time-consuming and shows a delayed response to disruptions within the fermentation process. As a new approach, we applied an online measurement technique (laser absorption spectroscopy) for real-time monitoring of stable carbon isotopes of methane (13C CH 4) in a pilot-scale biogas digester (3500 L) regularly fed with maize silage. Generally, isotopic composition of methane gives information about specific substrate degradation, that is, methanogenic pathways that reflect the actual digester state. First results of a 2-wk monitoring experiment show that stable carbon isotopes of methane respond promptly and highly dynamic to changes in the process state of the digester. In combination with other monitoring parameters (methane production rate, concentration of volatile fatty acids, and pH) the fluctuations in 13C CH 4 can be interpreted as a change in methanogenic pathways due to a high organic loading rate. In this context, 13C CH 4 might be used as a new parameter tool for monitoring and characterization of the process state of the digester

Modellrechnungen zur Wohnbaulandnachfrage im Landkreis Holzminden bis 1995 Anlage zum Bericht

TIB: AC 7613 (Anl) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman