The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein

An investigation was conducted into the influence of manure composition on the odour emission rate (OER) and the emission rate of ammonia (NH(3)), when diets containing 130, 160, 190 and 210gkg(-1) crude protein (CP) were fed to finishing pigs. A group of four boars and four gilts, housed in environmentally sealed pens, were assigned to each diet for a 23-day experimental period which was replicated three times (n=3). Ventilation air from each pen was sampled for NH(3) and odour, by olfactometry, on four days during the trial period. Simultaneous collections of manure were taken from the surface and base of each pit. The pH and the concentrations of dry matter, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids in the manure were measured. Manure composition differed between samples from the surface and base of the pit (P<0.05). Reducing dietary CP concentration decreased the emission of NH(3) (linear, P<0.001). The acetic acid:propionic acid ratio in manure samples was correlated to OER (r=0.79, P<0.001). There was a quadratic relationship between dietary CP concentration and OER (P<0.05). OER decreased between 210gkg(-1) and 160gkg(-1) CP and increased between 160gkg(-1) and 130gkg(-1) CP. In conclusion, reducing dietary crude protein levels could be used effectively to reduce ammonia emissions and OER, although no significant advantage was to be gained in OER from reducing crude protein level below 160gkg(-1).     

Quinazoline derivatives as MC-I inhibitors: evaluation of myocardial uptake using Positron Emission Tomography in rat and non-human primate

Several quinazoline derivatives were made as mitochondrial complex 1 inhibitors. Compound 4 showed an IC(50) of 11.3 nM and was the most potent compound of this series. The (18)F analog of 4, [(18)F] 4, was injected in the rat and showed high and rapid heart uptake, fast liver clearance, and low blood uptake. Images obtained using a microPET showed clear delineation of the myocardium in normal rats and perfusion deficit in ischemic rats. In the non-human primate, [(18)F] 4 showed rapid uptake and clearance from the myocardium and high liver uptake.     

Complex physiological traits as biomarkers of the sub-lethal toxicological effects of pollutant exposure in fishes

Complex physiological traits, such as routine aerobic metabolic rate or exercise performance, are indicators of the functional integrity of fish that can reveal sub-lethal toxicological effects of aquatic pollutants. These traits have proved valuable in laboratory investigations of the sub-lethal effects of heavy metals, ammonia and various xenobiotics. It is not known, however, whether they can also function as biomarkers of the complex potential range of effects upon overall functional integrity caused by exposure to mixtures of chemicals in polluted natural environments. The current study used portable swimming respirometers to compare exercise performance and respiratory metabolism of fish exposed in cages for three weeks to either clean or polluted sites on three urban European river systems: the river Lambro, Milan, Italy; the rivers Blythe, Cole and Tame, Birmingham, UK; and the river Amstel, Amsterdam, The Netherlands. The UK and Italian rivers were variously polluted with high levels of both bioavailable heavy metals and organics, and the Amstel by mixtures of bioavailable organics at high concentrations. In both the UK and Italy, indigenous chub (Leuciscus cephalus) exposed to clean or polluted sites swam equally well in an initial performance test, but the chub from polluted sites could not repeat this performance after a brief recovery interval. These animals were unable to raise the metabolic rate and allocate oxygen towards exercise in the second trial, an effect confirmed in successive campaigns in Italy. Swimming performance was therefore a biomarker indicator of pollutant exposure in chub exposed at these sites. Exposure to polluted sites on the river Amstel did not affect the repeat swimming performance of cultured cloned carp (Cyprinus carpio), indicating either a species-specific tolerance or relative absence of heavy metals. However, measurements of oxygen uptake during swimming revealed increased rates of routine aerobic metabolism in both chub and carp at polluted sites in all of the rivers studied, indicating a sub-lethal metabolic loading effect. Therefore, the physiological traits of exercise performance and metabolic rate have potential as biomarkers of the overall sub-lethal toxic effects of exposure to complex mixtures of pollutants in rivers, and may also provide insight into why fish do not colonize some polluted environments.     

Redirection of carotenoid metabolism for the efficient production of taxadiene [taxa-4(5),11(12)-diene] in transgenic tomato fruit

The taxanes are a group of polycyclic diterpenes produced by various species of yew. The potent anticancer drug paclitaxel (marketed as Taxol™) is the commercially most important taxane with annual sales in 2000 exceeding $1.6 billion. Paclitaxel is currently obtained either by direct extraction from yew trees or by the extraction of the precursor 10-deactilbaccatin III, which is then converted to paclitaxel by semi-synthesis. Apart from cost, one of the main draw backs to taxol in cancer treatment is the development of resistance by tumours, commonly due to the expression of ABC transporter efflux pumps which remove the drug from the target cell. A number of natural taxanes and semisynthetic derivates, have recently been shown to act as potent inhibitors of ABC transport proteins. These compounds have no effect upon microtubule polymerization (the normal target of paclitaxel), but have the ability to restore drug sensitivity when given in combination with paclitaxel to resistant cell lines. In work to be described elsewhere, we sort to carry out a structure function analysis of the ability of novel oxidised taxanes to act as ABC transporter inhibitors. For this study 100 mg or more of taxadiene [taxa-4(5),11(12)-diene], the first taxane in the paclitaxel pathway, was required as starting material from which to synthesize these compounds. Taxadiene is synthesised directly from geranylgeranyl diphosphate (GGPP), which is found in most plant tissues where it serves as a common precursor for many metabolites. The synthesis and use of GGDP are tightly regulated in most vegetative organs, however, in tomato fruit it is used almost exclusively for the production of coloured carotenoids which accumulate to high levels in the plastid as lycopene crystals. Expressing taxadiene synthase in a yellow-fruited tomato line that lacks the ability to utilise GGPP for carotenoid synthesis allowed GGPP normally utilised for making carotenoids to be re-routed for the production of taxadiene, allowing the facile extraction of 160 mg of highly pure taxadiene from 1 kg of freeze dried fruit.     

Amyloid formation via supramolecular peptide assemblies

Amyloid fibrils have been classically defined as linear, nonbranched polymeric proteins with a cross beta-sheet structure and the ability to alter the optical properties of the amyloid-specific dye Congo Red. Mounting evidence suggests that soluble oligomeric peptide assemblies approximately 2-20 nm in diameter are critical intermediates in amyloid formation. Using a pathogenic prion protein peptide comprised of residues 23-144, we demonstrate that, under quiescent but not agitated conditions, much larger globular assemblies up to 1 mum in diameter are made. These globules precede fibril formation and directly interact with growing fibril bundles. Fibrils made via these large spherical peptide assemblies displayed a remarkable diversity of ultrastructural features. Fibrillization of the Abeta1-40 peptide under similar conditions yielded similar results, suggesting a mechanism of general amyloid formation that can proceed through intermediates much larger than those previously described. Our data suggest that simply changing the physical microenvironment can profoundly influence the mechanism of amyloid formation and yield fibrils with novel ultrastructural properties.     

Salivaricin P, One of a Family of Two-Component Antilisterial Bacteriocins Produced by Intestinal Isolates of Lactobacillus salivarius

Lactobacillus salivarius DPC6005, a porcine intestinal isolate, produces a two-component bacteriocin, salivaricin P, with homology to ABP-118 produced by a human probiotic L. salivarius strain. Indeed, molecular characterization revealed that while the peptides Sln1 and ABP-118α are identical, their companion peptides (Sln2 and ABP-118β, respectively) differ by two amino acids. This observation suggests that two-component bacteriocins may be a common feature of intestinal L. salivarius strains.     

Bacterial-binding activity and plasma concentration of ladderlectin in rainbow trout (Oncorhynchus mykiss)

Soluble, defense lectins bind conserved microbial patterns leading to pathogen opsonization, enhanced phagocytosis and activation of complement. These immune functions, however, vary widely among individuals due to genetic and acquired differences affecting binding capacity or plasma concentration. Most evidence for the defensive function of soluble lectins is based on mammals, but several functionally homologous, but less well-characterized, lectins have been identified in fish. In this study, we compared binding of rainbow trout plasma ladderlectin to relevant, intact bacterial targets. A polyclonal antiserum raised against a synthetic peptide identical to the 20 N-terminal amino acids of the reduced 16 kDa rainbow trout ladderlectin subunit was used to detect plasma ladderlectin in immunoblots and indirect enzyme-linked immunosorbent assay (ELISA). Ladderlectin binding to Aeromonas salmonicida subsp. salmonicida, Aeromonas hydrophila, Yersinia ruckeri and Pseudomonas sp. was detected by PAGE and immunoblots of saccharide elutions from intact bacteria incubated in the presence of normal trout plasma. Although plasma concentrations of immunoreactive ladderlectin were low in the majority of trout, significant (P < 0.0001) variation between individual fish was observed in two separate populations. In addition, one population demonstrated a subset of individuals whose ladderlectin levels were approximately seven-fold higher than the population median. These findings indicate that rainbow trout have variable amounts of plasma ladderlectin capable of binding to the surfaces of several relevant bacterial targets.