| 1. |
- Abazov, V. M., et al.
(författare)
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Measurement of the Lambda(0)(b) lifetime using semileptonic decays
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 99:18, s. 182001-
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Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the Lambda(0)(b) lifetime using a sample corresponding to 1.3 fb(-1) of data collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. The Lambda(0)(b) baryon is reconstructed via the decay Lambda(0)(b)->mu(nu) over bar Lambda X-+(c). Using 4437 +/- 329 signal candidates, we measure the Lambda(0)(b) lifetime to be tau(Lambda(0)(b))=1.290(-0.110)(+0.119)(stat)(-0.091)(+0.087)(syst) ps, which is among the most precise measurements in semileptonic Lambda(0)(b) decays. This result is in good agreement with the world average value.
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| 2. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 3. |
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| 4. |
- Ainsworth, Elizabeth A., et al.
(författare)
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Next generation of elevated [CO2] experiments with crops: a critical investment for feeding the future world
- 2008
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Ingår i: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 31:9, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO2] provides a unique opportunity to increase the productivity of C-3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO2 responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO2 enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO2]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO2-responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future.
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| 5. |
- Crow, Allister, et al.
(författare)
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Crystal structure and biophysical properties of Bacillus subtilis BdbD: An oxidizing thiol:disulfide oxidoreductase containing a novel metal site
- 2009
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 284:35, s. 23719-23733
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Tidskriftsartikel (refereegranskat)abstract
- BdbD is a thiol: disulfide oxidoreductase (TDOR) from Bacillus subtilis that functions to introduce disulfide bonds in substrate proteins/peptides on the outside of the cytoplasmic membrane and, as such, plays a key role in disulfide bond management. Here we demonstrate that the protein is membrane-associated in B. subtilis and present the crystal structure of the soluble part of the protein lacking its membrane anchor. This reveals that BdbD is similar in structure to Escherichia coli DsbA, with a thioredoxin-like domain with an inserted helical domain. A major difference, however, is the presence in BdbD of a metal site, fully occupied by Ca2+, at an inter-domain position some 14 angstrom away from the CXXC active site. The midpoint reduction potential of soluble BdbD was determined as -75 mV versus normal hydrogen electrode, and the active site N-terminal cysteine thiol was shown to have a low pK(a), consistent with BdbD being an oxidizing TDOR. Equilibrium unfolding studies revealed that the oxidizing power of the protein is based on the instability introduced by the disulfide bond in the oxidized form. The crystal structure of Ca2+-depleted BdbD showed that the protein remained folded, with only minor conformational changes. However, the reduced form of Ca2+-depleted BdbD was significantly less stable than reduced Ca2+-containing protein, and the midpoint reduction potential was shifted by approximately -20 mV, suggesting that Ca2+ functions to boost the oxidizing power of the protein. Finally, we demonstrate that electron exchange does not occur between BdbD and B. subtilis ResA, a low potential extra-cytoplasmic TDOR.
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| 6. |
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| 7. |
- Lewin, Allison, et al.
(författare)
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Effects of substitutions in the CXXC active-site motif of the extracytoplasmic thioredoxin ResA
- 2008
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Ingår i: Biochemical Journal. - 0264-6021. ; 414, s. 81-91
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Tidskriftsartikel (refereegranskat)abstract
- The thiol-disulfide oxidoreductase ResA from Bacillus subtilis fulfils a reductive role in cytochrome c maturation. The pK(a) values for the CEPC (one-letter code) active-site cysteine residues of Ill are unusual for thioredoxin-like proteins ill that they are both high (> 8) and within 0.5 unit of each other. To determine the contribution of the inter-cysteine dipeptide of ResA to its redox and acid-base properties, three variants (CPPC, CEHC and CPHC) were generated representing a stepwise conversion into the active-site sequence of the high-potential DsbA protein from Escherichia coli. The substitutions resulted in large decreases in the pK(a) values of both the active-site cysteine residues: in CPHC (DsbA-type) ResA, Delta pK(a) values of -2.5 were measured for both cysteine residues. Increases in midpoint reduction potentials were also observed, although these were comparatively small: CPHC (DsbA-type) ResA exhibited all increase of +40mV compared with the wild-type protein. Unfolding studies revealed that, despite the observed differences in the properties of the reduced proteins, changes in stability were largely confined to file oxidized state. High-resolution structures of two of the variants (CEHC and CPHC ResA) in their reduced states were determined and are discussed in terms of the observed changes ill properties. Finally, the in vivo functional properties of CEHC RcsA are shown to be significantly affected compared with those of the wild-type protein.
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