The potential for short rotation energy forestry on restored landfill caps

This review examines the potential for producing biomass on restored landfills using willow and poplar species in short rotation energy forestry. In southern England, the potential production may be about 20 t ha(-1) of dry stem wood annually. However, actual yields are likely to be constrained by detrimental soil conditions, including shallow depth, compaction, low water holding capacity and poor nutritional status. These factors will affect plant growth by causing drought, waterlogging, poor soil aeration and nutritional deficiencies. Practical solutions to these problems include the correct placement and handling of the agricultural cap material, soil amelioration using tillage and the addition of organic matter (such as sewage sludge), irrigation (possibly using landfill leachate), the installation of drainage and the application of inorganic fertilizers. The correct choice of species and clone, along with good site management are also essential if economically viable yields are to be obtained. Further investigations are required to determine the actual yields that can be obtained on landfill sites using a range of management inputs.     

Activation of phosphoinositide 3-kinase gamma by Ras

BACKGROUND: Type I phosphoinositide 3-kinases are responsible for the hormone-sensitive synthesis of the lipid messenger phosphatidylinositol(3,4,5)-trisphosphate. Type IA and IB subfamily members contain a Ras binding domain and are stimulated by activated Ras proteins both in vivo and in vitro. The mechanism of Ras activation of type I PI3Ks is unknown, in part because no robust in vitro assay of this event has been established and characterized. Other Ras effectors, such as Raf and phosphoinositide-phospholipase Cepsilon, have been shown to be translocated into the plasma membrane, leading to their activation.RESULTS: We show that posttranslationally lipid-modified, activated N-, H-, K-, and R-Ras proteins can potently and substantially activate PI3Kgamma when using a stripped neutrophil membrane fraction as a source of phospholipid substrate. We have found GTPgammaS-loaded Ras can significantly (6- to 8-fold) activate PI3Kgamma when using artificial phospholipid vesicles containing their substrate, and this effect is a result of both a decrease in apparent Km for phosphatidylinositol(4,5)-bisphosphate and an increase in the apparent Vmax. However, neither in vivo nor in the two in vitro assays of Ras activation of PI3Kgamma could we detect any evidence of a Ras-dependent translocation of PI3Kgamma to its source of phospholipid substrate.CONCLUSIONS: Our data suggest that Ras activate PI3Kgamma at the level of the membrane, by allosteric modulation and/or reorientation of the PI3Kgamma, implying that Ras can activate PI3Kgamma without its membrane translocation. This view is supported by structural work that has suggested binding of Ras to PI3Kgamma results in a change in the structure of the catalytic pocket.     

Identification of the phosphotyrosine proteome from thrombin activated platelets

Signalling cascades are regulated both positively and negatively by tyrosine phosphorylation. Integrin mediated platelet adhesion triggers signal transduction cascades involving translocation of proteins and tyrosine phosphorylation events, ultimately causing large signalling complexes to be assembled. In resting platelets, a small number of phosphorylated proteins are evident with molecular mass of 50-62 kDa and 120-130 kDa. In thrombin activated human platelets, however, there is a large increase in the number of tyrosine phosphorylated signalling proteins detected. These proteins include pCas (130 kDa), FAK (125 kDa), PI(3)k (85 kDa) and src (85 kDa). However, it is unlikely that this list of proteins represents all the dynamic changes that occur after platelet activation and it is understood that more proteins remain unidentified. In this study, we propose a method for the isolation of the phosphotyrosine proteome from both resting and thrombin activated human platelets. All the dynamic phosphotyrosine events that occur in the platelet after thrombin activation were isolated by immunoprecipitation, using the monoclonal antibody 4G10, allowing us to obtain higher concentrations of relatively low abundant proteins. The resulting phosphotyrosine proteomes were separated by two-dimensional gel electrophoresis. Sixty-seven proteins were reproducibly found to be unique in the thrombin activated platelet proteome when compared to resting platelets. We have positively identified ten of these proteins by Western blotting and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry and these include FAK, Syk, ALK-4, P2X6 and MAPK kinase kinase. This proteomics approach to understanding the signalling events following platelet activation may elucidate potential drug targets for the treatment of coronary thrombosis.     

VIRTUAL2D: A web-accessible predictive database for proteomics analysis

The available archive of sequence databases compiled from whole genome projects and budding proteomics efforts have enabled us to develop VIRTUAL2D, an interactive system for the assembly of virtual protein expression maps computed on the basis of theoretical isoelectric focusing point, molecular weight, tissue specificity and relative abundance for any set of proteins currently catalogued. This tool will assist in the preliminary, albeit putative, prediction of the identity and location of unknown and/or low abundance proteins in experimentally derived two-dimensional polyacrylamide gel electrophoresis maps.     

Determination of the structure of chiral molecules using ab initio vibrational circular dichroism spectroscopy

We discuss the theoretical prediction of vibrational circular dichroism (VCD) spectra using ab initio density functional theory (DFT) and the application of this methodology to the determination of the absolute configurations and conformations of chiral molecules.     

Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body

Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.