Characterisation of organic phosphorus in overland flow from grassland plots using 31P nuclear magnetic resonance spectroscopy

Grazing animals are known to change the characteristics of agricultural grasslands as a source of and pathway for phosphorus (P) loss to water. Previous work, using physico-chemical analysis of the overland flow revealed that the presence of grazing animals increased the overall quantity of P being lost, in particular the unreactive and particulate P fractions. The aim of this study was to characterise the organic P (Po) fraction in overland flow from grazed and non-grazed grassland small plots using phosphorus-31 nuclear magnetic resonance (³¹P NMR) spectroscopy to give greater insight into P loss to water under simulated rainfall. The effect of the grazing animal was most pronounced in the dissolved unreactive P (DUP) and particulate unreactive P (PUP) fractions measured in overland flow from the grazed plots, over four times higher than from the non-grazed plots. Five distinct classes of P compounds were detected in the ³¹P NMR spectra, inorganic orthophosphate (δ = 6.83 ppm), orthophosphate monoesters (δ = 4.95–5.69 ppm), orthophosphate diesters (δ = 1.89 ppm), phosphonates (δ = 19.38 ppm), and pyrophosphates (δ = −3.26 ppm). Distinct signals at 5.69, 5.37, 5.10, and 4.95 ppm in the overland flow extracts from the plots indicated significant concentrations of myo -inositol hexakisphosphate in the orthophosphate monoester region. Orthophosphate diesters (assigned to phospholipids) and phosphonates were also only detected in overland flow collected from the grazed plot. These results indicate that normal grazing management practices may not only affect the concentrations of Po but also the forms of Po being transferred from grassland systems to water.     

Plant and animal endemism in the eastern Andean slope: challenges to conservation

Background

The Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants) and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients) with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioner's scale (1:250,000-1:1,000,000), based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas.

Results

We found that sizes of endemic species distributions ranged widely (< 20 km² to > 200,000 km²) across the study area. Bird and mammal endemic species richness was greatest within a narrow 2500-3000 m elevation band along the length of the Andes Mountains. Endemic amphibian richness was highest at 1000-1500 m elevation and concentrated in the southern half of the study area. Geographical distribution of plant endemism was highly taxon-dependent. Irreplaceable areas, defined as locations with the highest number of species with narrow ranges, overlapped slightly with areas of high endemism, yet generally exhibited unique patterns across the study area by species group. We found that many endemic species and ecological systems are lacking national-level protection; a third of endemic species have distributions completely outside of national protected areas. Protected areas cover only 20% of areas of high endemism and 20% of irreplaceable areas. Almost 40% of the 91 ecological systems are in serious need of protection (= < 2% of their ranges protected).

Conclusions

We identify for the first time, areas of high endemic species concentrations and high irreplaceability that have only been roughly indicated in the past at the continental scale. We conclude that new complementary protected areas are needed to safeguard these endemics and ecosystems. An expansion in protected areas will be challenged by geographically isolated micro-endemics, varied endemic patterns among taxa, increasing deforestation, resource extraction, and changes in climate. Relying on pre-existing collections, publically accessible datasets and tools, this working framework is exportable to other regions plagued by incomplete conservation data.     

Matrix metalloproteinases in inflammatory pathologies of the horse

The extracellular matrix (ECM) of connective tissue is constantly being remodelled to allow for growth and regeneration. Normal tissue maintenance requires the ECM components to be degraded and re-synthesised in relatively equal proportions. This degradation is facilitated by matrix metalloproteinases (MMPs) and their proteolytic action is controlled primarily by the tissue inhibitors of metalloproteinases (TIMPs). Both MMPs and TIMPs exist in a state of dynamic equilibrium, with a slight excess of one or the other depending on the need for either ECM breakdown or synthesis. Long-term disruption to this balance between MMPs and TIMPs will have pathological consequences.Matrix metalloproteinases are involved in a number of diseases in mammals, including the horse. Excess MMP activity can cause ECM destruction, as seen in the lamellar basement membrane in laminitis and the articular cartilage in osteoarthritis. Matrix metalloproteinase under-activity can potentially impede healing by preventing fibrinolysis in fibrotic conditions and the removal of scar tissue in wounds. Matrix metalloproteinases also degrade non-ECM proteins and regulate cell behaviour via the release of growth factors from the substrates they cleave, increasing the scope of their effects. This review looks at the involvement of MMPs in equine health and pathologies, whilst exploring the potential consequences of therapeutic intervention.     

Antimicrobial susceptibility of Clostridium perfringens isolates of bovine, chicken, porcine, and turkey origin from Ontario

Antimicrobial susceptibilities and toxin types were determined for 275 Clostridium perfringens isolates collected in Ontario in the spring of 2005. Minimal inhibitory concentrations (MICs) of C. perfringens isolates for 12 antimicrobials used in therapy, prophylaxis, and/or growth promotion of cattle (n = 40), swine (n = 75), turkeys (n = 50), and chickens (n = 100) were determined using the microbroth dilution method. Statistical analyses and MIC distributions showed reduced susceptibility to bacitracin, clindamycin, erythromycin, florfenicol, and tetracycline for some isolates. Reduced susceptibility to bacitracin was identified in chicken (64%) and turkey (60%) isolates. Swine isolates had predominantly reduced susceptibility to clindamycin (28%) and erythromycin (31%), whereas bovine isolates had reduced susceptibility to clindamycin (10%) and florfenicol (10%). Reduced susceptibility to tetracycline was spread across all species. No clear reduced susceptibility, but elevated MIC(50) for virginiamycin was found in chicken isolates in comparison with isolates from other species. Toxin typing revealed that C. perfringens type A is the dominant toxin type isolated in this study across all 4 host species.     

Analysis of Environmental Samples Using Microwave-Assisted Acid Digestion and Inductively Coupled Plasma Mass Spectrometry: Maximizing Total Element Recoveries

For the routine determination of metals in environmental samples, we require microwave-assisted digestion methods that yield ‘total’ or ‘near-total’ recoveries while avoiding the use of HF acid. As inductively coupled plasma mass spectrometry (ICP-MS) is the method of detection, it is desirable to minimize the use of HCl to avoid spectral interferences caused by high Cl^– concentrations. Using certified reference materials, we performed a series of modifications to the US EPA method 3051 which included: increasing the temperature and durations of microwave digestion, varying the ratio of sample mass to acid volume, and alterations to the compositions of the acid digestion mixture. The experiments were conducted using urban particulate matter (NIST-1648), coal fly ash (NBS-1633) and six CANMET certified reference materials (Till-2, Till-3, Till-4, LKSD-1, LKSD-2 and LKSD-4), in two laboratories (Health Canada and Environment Canada) using different microwave digestion systems and different ICP-MS instruments. Our modified microwave-assisted nitric acid digestion method improved recoveries for Pb, Zn, V, Fe and Cu approaching ‘total’ recoveries in the same matrices determined using X-ray fluorescence (XRF) and instrumental neutron activation analysis (INAA) as reported in the certificates of analysis. Recoveries for other elements such as Cr and Ni compared well with ‘near-total’ recoveries yielded by traditional (non-assisted) acid digestion methods.     

Headspace sorptive extraction (HSSE), stir bar sorptive extraction (SBSE), and solid phase microextraction (SPME) applied to the analysis of roasted Arabica coffee and coffee brew.

Headspace sorptive extraction (HSSE) and stir bar sorptive extraction (SBSE), two recently introduced solventless enrichment techniques, have been applied to the analysis of the headspace of Arabica roasted coffee and of the headspace of the brew and of the brew itself. In both HSSE and SBSE enrichment is performed on a thick film of poly(dimethylsiloxane) (PDMS) coated onto a magnet incorporated in a glass jacket. Sampling is done by placing the PDMS stir bar in the headspace (gas phase extraction or HSSE) or by immersing it in the liquid (liquid phase extraction or SBSE). The stir bar is then thermally desorbed on-line with capillary GC-MS. The performance of HSSE and SBSE have been compared through the determination of the recoveries and relative abundances of 16 components of the coffee volatile fraction to classical static headspace (S-HS) and to headspace and in-sample solid phase microextraction (HS-SPME and IS-SPME, respectively) applying the fibers PDMS 100 microm, Carbowax/divinylbenzene 65 microm (CW/DVB), Carboxen/PDMS 75 microm(CAR/PDMS), polyacrylate 85 microm(PA), PDMS/divinylbenzene 65 microm(PDMS/DVB), and Carboxen/divinylbenzene/PDMS 50-30 microm(CAR/PDMS/DVB). In all cases, HSSE and SBSE gave higher recoveries, and this is entirely due to the high amount of PDMS applied.