Land Use Implications of Increased Biomass Production Identified by GIS-Based Suitability and Yield Mapping for Miscanthus in England

The need for climate change mitigation and to meet increasing energy demands has led to a rise in the land area under bioenergy crops in many countries. There are concerns that such large-scale land conversion will conflict with food production and impact on the environment. Perennial biomass crops could be grown on more marginal agricultural land. However, for sustainable solutions, biomass yields will need to be sufficient and the wider implications of land-use changes considered. Here, focusing on Miscanthus in England as an example, we combined an empirical model with GIS to produce a yield map and estimated regional energy generation potentials after masking out areas covered by environmental and socio-economic factors which could preclude the planting of energy crops. Agricultural land quality and the distributions of currently grown food crops were then taken into account. Results showed that: (i) regional contrasts occur in the importance of different factors affecting biomass planting; (ii) areas with the highest biomass yields co-locate with food producing areas on high grade land, and; (iii) when such high grade land and unsuitable areas are excluded, a policy-related scenario for increased planting on 350,000 ha utilised 4–28% (depending on the region) of lower grade land and would not necessarily greatly impact on UK food security. We conclude that the GIS-based yield and suitability mapping described here can help identify important issues in bioenergy generation potentials and land use implications at regional or finer spatial scales that would be missed in analyses at the national level.     

Kinetics control preferential heterodimer formation of platelet-derived growth factor from unfolded A- and B-chains

The folding and assembly of platelet-derived growth factor (PDGF), a potent mitogen involved in wound-healing processes and member of the cystine knot growth factor family, was studied. The kinetics of the formation of disulfide-bonded dimers were investigated under redox reshuffling conditions starting either from unfolded and reduced PDGF-A- or B-chains or an equimolar mixture of both chains. It is shown that in all cases the formation of disulfide-bonded dimers is a very slow process occurring in the time scale of hours with a first-order rate-determining step. The formation of disulfide-bonded PDGF-AA or PDGF-BB homodimers displayed identical kinetics, indicating that both monomeric forms as well as the dimerized homodimer have similar folding and assembly pathways. In contrast, the formation of the heterodimer occurred three times more rapidly compared with the formation of the homodimers. As both monomeric forms revealed similar renaturation kinetics, it can be concluded that the first-order rate-determining folding step does not occur during monomer folding but must be attributed to conformational rearrangements of the dimerized, not yet disulfide-bonded protein. These structural rearrangements allow a more rapid formation of intermolecular disulfide bonds between the two different monomers of a heterodimer compared with the formation of the disulfide bonds between two identical monomers. The preferential formation of disulfide-bonded heterodimers from an equimolar mixture of unfolded A- and B-chains is thus a kinetically controlled process. Moreover, similar activation enthalpies for the formation of all different isoforms suggest that faster heterodimerization is controlled by entropic factors.     

Oxidative damage and anti-oxidant capacity in two migratory bird species at a stop-over site

We quantified in the garden warbler (Sylvia borin) and the barn swallow (Hirundo rustica), two long-distance migratory songbirds, the early oxidative damage (ROMs) and plasma anti-oxidant capacity (OXY) variation of individuals caught at a stop-over site after a sustained flight across the sea, during spring migration. Our main goal was to quantify the oxidative damage and anti-oxidant capacity variation in these two migratory species in relation to fat and muscle stores. The birds were sampled in Ponza, a small island along the migratory route of these species. The levels of ROMs and OXY did not show any differences between the two species and in general were higher in individuals with higher fat and protein stores. Nevertheless, the balance between ROMs and OXY was better in individuals in good condition. These patterns were similar in both species. No sex differences emerged for both ROMs and OXY in the barn swallow, the only species that could be sexed. Both markers of oxidative stress did not show any significant variation across a 30-min restrained experiment. These data are the first of this kind in wild birds in a migratory context and suggest that individuals in better condition are exposed to lower oxidative stress, providing an indirect evidence of the oxidative cost caused by prolonged flights.     

Palmitate acutely raises glycogen synthesis in rat soleus muscle by a mechanism that requires its metabolization (Randle cycle)

The acute effect of palmitate on glucose metabolism in rat skeletal muscle was examined. Soleus muscles from Wistar male rats were incubated in Krebs-Ringer bicarbonate buffer, for 1 h, in the absence or presence of 10 mU/ml insulin and 0, 50 or 100 microM palmitate. Palmitate increased the insulin-stimulated [(14)C]glycogen synthesis, decreased lactate production, and did not alter D-[U-(14)C]glucose decarboxylation and 2-deoxy-D-[2,6-(3)H]glucose uptake. This fatty acid decreased the conversion of pyruvate to lactate and [1-(14)C]pyruvate decarboxylation and increased (14)CO(2) produced from [2-(14)C]pyruvate. Palmitate reduced insulin-stimulated phosphorylation of insulin receptor substrate-1/2, Akt, and p44/42 mitogen-activated protein kinases. Bromopalmitate, a non-metabolizable analogue of palmitate, reduced [(14)C]glycogen synthesis. A strong correlation was found between [U-(14)C]palmitate decarboxylation and [(14)C]glycogen synthesis (r=0.99). Also, palmitate increased intracellular content of glucose 6-phosphate in the presence of insulin. These results led us to postulate that palmitate acutely potentiates insulin-stimulated glycogen synthesis by a mechanism that requires its metabolization (Randle cycle). The inhibitory effect of palmitate on insulin-stimulated protein phosphorylation might play an important role for the development of insulin resistance in conditions of chronic exposure to high levels of fatty acids.     

The Probiotic Mixture VSL#3 Accelerates Gastric Ulcer Healing by Stimulating Vascular Endothelial Growth Factor

Studies assessing the effect and mechanism of probiotics on diseases of the upper gastrointestinal tract (GI) including gastric ulcers are limited despite extensive work and promising results of this therapeutic option for other GI diseases. In this study, we investigated the mechanisms by which the probiotic mixture VSL#3 (a mixture of eight probiotic bacteria including Lactobacilli, Bifidobacteria and Streptococcus species) heals acetic acid induced gastric ulcer in rats. VSL#3 was administered orally at low (6×10⁹ bacteria) or high (1.2×10¹⁰ bacteria) dosages from day 3 after ulcer induction for 14 consecutive days. VSL#3 treatments significantly enhanced gastric ulcer healing in a dose-dependent manner. To assess the mechanism(s) whereby VSL#3 exerted its protective effects, we quantified the gene expression of several pro-inflammatory cytokines, protein and expression of stomach mucin-Muc5ac, regulatory cytokine-IL-10, COX-2 and various growth factors. Of all the components examined, only expression and protein production of VEGF was increased 332-fold on day 7 in the ulcerated tissues of animals treated with VSL#3. Predictably, animals treated with VEGF neutralizing antibody significantly delayed gastric ulcer healing in VSL#3 treated animals. This is the first report to demonstrate high efficacy of the probiotic mixture VSL#3 in enhancing gastric ulcer healing. Probiotic efficacy was effective at higher concentrations of VSL#3 by specifically increasing the expression and production of angiogenesis promoting growth factors, primarily VEGF.     

Solution structure of reduced Clostridium pasteurianum rubredoxin

The solution structure of reduced Clostridium pasteurianum rubredoxin (MW 6100) is reported here. The protein is highly paramagnetic, with iron(II) being in the S=2 spin state. The Hβ protons of the ligating cysteines are barely observed, and not specifically assigned. Seventy-six percent of the protons have been assigned and 1267 NOESY peaks (of which 1037 are meaningful) have been observed. Nonselective T ₁ measurements have been measured by recording four nonselective 180°-τ-NOESY at different τ values, and fitting the intensity recoveries to an exponential recovery. Thirty-six metal-proton upper and lower distance constraints have been obtained from the above measurements. The use of such constraints is assessed with respect to spin delocalization on the sulfur donor atoms. The solution structure obtained with the program DYANA has been refined through restrained energy minimization. A final family of 20 conformers is obtained with no distance violations larger than 0.24?Å, and RMSD values to the mean structure of 0.58 and 1.03?Å for backbone and all heavy atoms, respectively (measured on residues 3–53). The structure is compared to the X-ray structure of the oxidized and of the zinc substituted protein, and to the available structures of other rubredoxins. In particular, the comparison with the crystal structure and the solution structure of the Zn derivative of the highly thermostable Pyrococcus furiosus rubredoxin suggested that the relatively low thermal stability of the clostridial rubredoxin may be tentatively ascribed to the loosening of its secondary structure elements. This research is a further achievement at the frontier of solution structure determinations of paramagnetic proteins.     

CPEB: a life in translation

Nearly two decades ago, Xenopus oocytes were found to contain mRNAs harboring a small sequence in their 3' untranslated regions that control cytoplasmic polyadenylation and translational activation during development. This cytoplasmic polyadenylation element (CPE) is the binding platform for CPE-binding protein (CPEB), which promotes polyadenylation-induced translation. Since then, the biochemistry and biology of CPEB has grown rather substantially: mechanistically, CPEB nucleates a complex of factors that regulates poly(A) elongation through, of all things, a deadenylating enzyme; biologically, CPEB mediates many processes including germ-cell development, cell division and cellular senescence, and synaptic plasticity and learning and memory. These observations underscore the growing complexities of CPEB involvement in cell function.