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Biomedical subjects

C F Moffat

Publications and source records attributed to C F Moffat.

At least 19 recordsLinked to original sources
PubMed2006

Application of SSH and a macroarray to investigate altered gene expression in Mytilus edulis in response to exposure to benzo[a]pyrene.

The lack of genomic resources for aquatic invertebrates restricts their use as sentinel species in coastal environments. It is known that where genomic data are not available, suppression subtractive hybridisation (SSH) can generate cDNA libraries representative of pollutant-responsive gene transcription in aquatic vertebrates. To assess whether the approach was equally suited to aquatic invertebrates, altered gene expression in digestive gland of the mussel, Mytilus edulis, in response to exposure to benzo[a]pyrene (BaP) (1 mg/l) was investigated with SSH and a nylon macroarray. Screening of the subtracted libraries showed 112/250 up-regulated and 25/55 down-regulated clones were positive for differential expression and characterisation of these identified 87 with unique sequence suitable for array on a nylon membrane. The transcripts isolated were from a diverse range of genes involved in general stress, oxidative stress, cell adhesion, transcriptional and translational regulation, transport mechanisms, energy metabolism, cell metabolism, lipid metabolism, protein turnover and activation, lysosomal activity and 22 cryptic clones. Subsequent use of the clones in macroarray format to analyse expression of BaP-responsive genes (0 vs 4 day exposed) showed 0-100-fold increased levels of the forward-subtracted probes and between 0 and 0.1-fold down-regulation of the reverse-subtracted probes. Only 15% of the clones showed less than 2-fold change in expression. The gene ontology of the transcripts isolated demonstrates that BaP elicits a multitude of responses with a major feature being disruption of cellular redox status. The results indicate that the use of SSH and a macroarray is a robust method to discover novel pollutant-responsive genes in aquatic invertebrates.

Animals↗
PubMed2005

The effects of oil exploration and production in the Fladen Ground: composition and concentration of hydrocarbons in sediment samples collected during 2001 and their comparison with sediment samples collected in 1989.

Due to the potentially accumulative nature of the Fladen Ground, an area of intense oil activity in the North Sea, a survey was carried out in 1989 to map the distribution of contamination in relation to these oil activities. All the sediments collected were screened by ultraviolet fluorescence (UVF) for polycyclic aromatic hydrocarbons (PAHs) and selected samples were analysed for n-alkanes (by GC-FID), PAHs and biomarkers (by GC-MSD). This survey was repeated in 2001, with all the 1989 sites being resampled. All of these sediments were analysed for UVF oil equivalents, PAHs, n-alkanes and biomarkers. The concentrations of these parameters decreased between 1989 and 2001, with average decreases ranging from 43% to 88%. In addition, no significant difference was found, for all the parameters, between near field (<5 km from an oil installation) and far field (>5 km from an oil installation) sites in 2001 indicating that the Fladen Ground is approaching a 'steady state' or background concentration for contamination.

Carbon↗
PubMed2004

The polycyclic aromatic hydrocarbon and geochemical biomarker composition of sediments from sea lochs on the west coast of Scotland.

Sediments from twelve sea lochs on the west coast of Scotland were analysed for parent and branched 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs), n-alkanes and geochemical biomarkers (triterpanes). Where possible at least fourteen sediment samples were collected at random from each sea loch. All sea lochs were remote, most had limited industrial and urban inputs, although all had fish farms. Four lochs had moderate total PAH concentrations and eight lochs had high total PAH concentrations. Total PAH concentration was related to organic carbon content and particle size distribution, with sandier sediments having lower PAH concentrations. The highest total PAH concentrations, normalised for organic carbon, were in Loch Linnhe and Ballachulish Bay (Loch Leven), close to an aluminium smelter. PAH concentration ratios showed that pyrolysis was the main source of PAHs in most lochs. Only sediments from Loch Clash showed evidence of petrogenic input based on their geochemical biomarker (triterpane and sterane) and n-alkane profiles. PAH profiles were similar across lochs apart from Loch Linnhe and Ballachulish Bay, which had a greater proportion of heavy parent PAHs. West coast sediments had a smaller proportion of heavy PAHs than sediments collected from voes in Shetland and a smaller proportion of alkylated PAHs relative to sediments collected from coastal waters around Orkney.

Environmental Monitoring↗
PubMed2004

Polycyclic aromatic hydrocarbon (PAH) concentration and composition determined in farmed blue mussels (Mytilus edulis) in a sea loch pre- and post-closure of an aluminium smelter.

Concentrations of polycyclic aromatic hydrocarbons (2- to 6-ring parent and branched PAH) from an actively producing commercial shellfish farm in Loch Leven, Scotland, were found in excess of 4000 ng g(-1) wet weight tissue. These concentrations were considerably greater than had been recorded from mussels sampled elsewhere around the Scottish mainland. The PAH composition of the mussels from Loch Leven was dominated by the 5-ring, parent compounds; benzo[b]fluoranthene was the dominant compound. This data was consistent with the source being a discharge from an aluminium smelter. The individual compounds benz[a]anthracene, benzo[a]pyrene and dibenz[a,h]anthracene returned values of 304 ng g(-1), 446 ng g(-1) and 39 ng g(-1) respectively; these were well above the 15 ng g(-1) pragmatic guideline limit. Over the two year monitoring period, the concentrations of these compounds in mussels from Loch Etive, a reference location, ranged between 'not detected' and 4 ng g(-1)(for benz[a]anthracene). Mussels were transferred from a clean location to Loch Leven which demonstrated that the rate of uptake of PAH was rapid. Following closure of the aluminium smelter, the PAH concentrations in mussels decreased. Differences between the two sites within Loch Leven were noted with the longer-term impact remaining greater for the mussels closer to the original point discharge.

Animals↗
PubMed2003

The polycyclic aromatic hydrocarbon composition of mussels (Mytilus edulis) from Scottish coastal waters.

Blue mussels (Mytilus edulis) were collected from coastal areas and voes in Shetland and Orkney during March and April 1998 and from various coastal locations around mainland Scotland and from the Islands during October and December 1999. The polycyclic aromatic hydrocarbon concentration and composition (2- to 6-ring parent and branched) were determined for all samples. Additional analysis, including sensory assessment and the determination of n-alkanes and geochemical biomarkers, was also undertaken on the Shetland and Orkney mussels collected in 1998. Mussels from Shetland and Orkney exhibited a wide range of total PAH concentration (14.7 to 7,177 ng g(-1) wet weight). Those mussels collected in 1999 exhibited a narrower concentration range. The lowest value (mussels from Loch Kentra) was 8.4 ng g(-1) wet weight while the maximum concentration was 344.1 ng g(-1) wet weight and was determined in mussels from Granton East in the Firth of Forth. The PAH concentration ratios in mussels from Dury Voe (Grunna), Long Hope and Kirkwall Bay were consistent with a predominately petrogenic source for these contaminants. This was supported by both the sensory assessment and the n-alkane and triterpane profiles. Comparisons of the PAH concentrations in mussels with sediments collected from the same locations around Shetland and Orkney showed that in areas of high sediment PAH concentration the bioavailability of these contaminants was limited.

Animals↗
PubMed2001

Biliary PAH metabolites and EROD activity in flounder (Platichthys flesus) from a contaminated estuarine environment.

The present study in the Firth of Forth, Scotland, emphasises the usefulness of biliary metabolite measurements in estuarine monitoring using the flounder (Platichthys flesus). The short time scale (a few hours) of response to polycyclic aromatic hydrocarbon (PAH) exposure, allowed clearer interpretation of trends and differences between sites. Such differences and trends in the metabolite data were not as apparent from 7-ethoxyresorufin O-deethlyation (EROD) activity measurements, which were likely to have been blurred by the movements of flounder between sites. Statistical differences were not observed in EROD activity in flounder from the Firth of Forth (ANOVA, P = 0.065). The biliary metabolites showed statistical differences between the uppermost site of Longannet and Port Edgar, in the outer Firth, for both the 1-OH pyrene and 2-OH naphthalene metabolites (ANOVA, Tukeys, P = 0.012 and 0.022 respectively). There was also a significant correlation between the concentrations of all three individual metabolites (1-OH pyrene, 2-OH naphthalene, I-OH phenanthrene) and the log of the distance downstream from the major PAH input sources of Longannet power station and Grangemouth. Biliary PAH metabolites were shown to better reflect local contamination gradients than EROD activity. This is explained by the relative response times of the two biomarkers and local movements of the flounder in the estuary.

Animals↗
PubMed2001

The polycyclic aromatic hydrocarbon and geochemical biomarker composition of sediments from voes and coastal areas in the Shetland and Orkney Islands.

Marine sediments from coastal areas and voes in the Shetland and Orkney Islands were analysed for parent and branched 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) and geochemical biomarkers. Where possible 14 sediment samples were collected at random from each of 17 Shetland and 9 Orkney sites. The wide range of total PAH concentrations in sediments (i.e., < LOD up to 22619 ng g(-1) dry weight) was indicative of a variety of anthropogenic activities and different sediment types associated with the specific locations. Low PAH concentrations were determined in sandy sediments from areas of limited boat activity. The highest PAH concentrations were found in muddy sediment close to a boat repair yard. PAH concentration ratios were consistent with the main source of these compounds, in most areas, being pyrolysis. Geochemical biomarker (triterpane and sterane) profiles from the sediment were indicative, for some areas, of limited petrogenic input. Punds Voe was the only voe to show evidence of North Sea oil. PAH profiles were similar across sites within each island group, with any differences attributable to known local sources of PAHs. However, there was a clear difference in the PAH profiles of Shetland and Orkney sediments, with Orkney sediments having a higher proportion of the lighter alkylated PAHs.

Environmental Monitoring↗
PubMed2000

Measurement of oilfield chemical residues in produced water discharges and marine sediments.

During oil production, significant quantities of water are produced with the crude oil which, following treatment on the platform, are discharged to the marine environment. This produced water contains residues of oilfield chemicals added by the platform operators to the topside processing equipment to aid oil-water separation and mitigate operational problems. The levels of oilfield chemicals entering the marine environment via this route were investigated using electrospray ionisation tandem mass spectrometry (ESI-MS/MS) and wet chemical analysis techniques. The generic nature of different chemical types was shown by ESI-MS/MS. Studies of the partitioning behaviour of corrosion inhibitors and demulsifiers between the oil and water phases of the produced fluids suggested corrosion inhibitors partitioned primarily into the aqueous phase and demulsifiers into the oil phase. This was reflected in levels observed in produced water although, in the case of a corrosion inhibitor, lower than expected concentrations were measured. Scale inhibitors were discharged with the produced water at their dosing concentrations. Marine sediments in the proximity of two North Sea oil platforms contained low levels of benzalkonium quaternary ammonium salts (0.74-10.84 ng/g), typical corrosion inhibitor chemicals.

Electron Spin Resonance Spectroscopy↗
PubMed2000

Analysis of sediments from Shetland Island voes for polycyclic aromatic hydrocarbons, steranes and triterpanes.

A few days after the grounding of the oil tanker Braer on 5 January 1993, an Exclusion Zone was designated by Order under the Food and Environment Protection Act 1985, prohibiting the harvesting of farmed or wild shellfish within the Zone to prevent contaminated products reaching the market place. The order was progressively lifted for species that were found to be free of petrogenic taint and for which the polycyclic aromatic hydrocarbon (PAH) levels were within the range for reference samples. This Order, however, still remains in place for mussels (Mytilus edulis) as the PAH levels are higher than in reference mussels. To investigate the possible source of PAHs found in these mussels, sediments were collected from three reference and three Zone sites and their hydrocarbon compositions studied using the n-alkane composition and concentration, PAH composition and concentration and the sterane and triterpane composition. The reference site at Olna Firth was found to have the highest levels of 2-6-ring parent and branched PAHs, the highest concentration in one of the pooled sediments being 4,530 ng g(-1) dry weight. Values in the other two reference sites (Vaila Sound and Mangaster Voe) ranged from 248.7 to 902.2 ng g(-1) dry weight. PAH concentrations at the Zone sites (Sandsound Voe, Stromness Voe and Punds Voe) ranged from 641.0 to 2,766 ng g(-1) dry weight. The PAH data were normalised to the percentage of organic carbon and log-transformed prior to being analysed using principal component analysis. The mean total PAH concentrations for Zone sites were found not to be significantly different from the reference sites. The PAH concentration ratios were consistent with the main source of PAHs being pyrolysis. However, there was a petrogenic contribution, suggested by the presence of alkylated PAHs, with Punds Voe having the largest petrogenic hydrocarbon content. This was supported by the triterpane profiles and the presence of a UCM in the aliphatic chromatograms from Punds Voe sediments.

Animals↗
PubMed1998

Dietary intake and tissue concentration of fatty acids in omnivore, vegetarian and diabetic pregnancy.

The aim of this study was to determine the effect of fatty acid intake and insulin dependent diabetes on the fatty acid composition of maternal erythrocytes, the placenta and cord. Fatty acid intake (from food frequency questionnaire) and the fatty acid composition of maternal erythrocytes, the placenta and cord from pregnant vegetarians (n = 4) and insulin dependent diabetics (n = 5) was compared with pregnant omnivores (n = 10). There was a significantly lower intake of n-6 long chain polyunsaturated fatty acid (LCPUFA) (-75% P < 0.01) and n-3 LCPUFA (-92% P < 0.01) and increased ratio of n-6/n-3 LCPUFA in the vegetarians (103%; P < 0.001). The concentrations of 22:4 n-6 (+28%; P < 0.05) and 22:5 n-3 (+40%; P < 0.05) were higher in vegetarian erythrocytes. Placental 18:2 n-6 (+26.9%; P < 0.05) 18:3 n-3 (+139%; P < 0.05) and 22:5 n-3 (+24%; P < 0.05) were increased while 20:5 n-3 (-36%; P < 0.05), 22:6 n-3 (-16%; P = 0.059), and the ratios of 20:4 n-6/18:2 n-6 (P < 0.01) and 22:6 n-3/18:3 n-3 were reduced. 22:6 n-6 (-49%; P < 0.05) and total n-3 LCPUFA (-11%; P < 0.01) were reduced in vegetarian cord. For the diabetic mothers, all of the n-6 LCPUFA and n-3 LCPUFA were reduced in the maternal erythrocytes; 22:4 n-6 (-42%; P < 0.05), 22:5 n-6 (-46%; P < 0.05) and 22:6 n-3 (-41%; P < 0.05). For the diabetic placenta and cord the general pattern of n-3 LCPUFA was the same as that in the vegetarians. In the vegetarian mothers, the PUFA profiles in the maternal erythrocytes, placenta and cord are consistent with an elevation in the rate of LCPUFA synthesis in order to make up the relative deficit in LCPUFA intake. However, it may be that the higher level of desaturase activity is not able to overcome the dietary deficit of 22-6 n-3 and 22:6 n-6. Despite the fact that the dietary LCPUFA intake in the pregnant diabetic was comparable with that in the pregnant 'normal' omnivore mothers, the pattern of PUFA in the tissues resembled that of the vegetarian mothers.

Diabetes Mellitus, Type 1↗
PubMed1997

Heparinase-II-catalyzed degradation of N-propionylated heparin.

Currently there is great interest in the preparation of modified heparins and heparin-like polymers that possess specific and useful bioactivities. This paper demonstrates the potential of a particularly versatile endopolysaccharide lyase (heparinase II) as an analytical tool with which to assess both the chemical modification occurring during synthesis of such polymers and the actual primary structure of the final product of the enzyme activity. Additionally, the work widens our knowledge of the specificity range of this enzyme. The study involved a novel derivative of heparin containing the unnatural N-propionyl group, which was prepared from de-N-sulfated heparin. The extent of the chemical modification was followed throughout the preparation process by incubating samples with heparinase II and analyzing, with HPLC, the products of degradation catalyzed by the enzyme.

Acylation↗
PubMed1992

Cu(2+)-heparin interaction studied by polarimetry.

Plots analogous to isothermal binding curves were derived from polarimetric studies of solutions of Na(+)-heparin to which Cu2+ was added. The shape of the plots suggests that discrete Cu(2+)-heparin complexes may form, the nature and stoichiometry of which depend upon the conditions under which the interaction occurs. Initially, complexes were formed with a stoichiometry of about 1 Cu2+ ion per heparin tetrasaccharide unit. Under these conditions, the complex may exist as a colloid-like phase that is not subject to simple solution equilibrium processes, and that is maintained by forces in addition to electrostatic ones. Further addition of Cu2+ resulted in the formation of a different complex with a stoichiometry of about 1 Cu2+ ion per disaccharide unit.

Cations↗
PubMed1992

A study of Ca(2+)-heparin complex-formation by polarimetry.

Possible inflexions in isothermal binding plots derived from equilibrium-dialysis measurements and in equivalent plots obtained by polarimetric measurements accord with the possibility that discrete Ca(2+)-heparin-water complexes/phases may exist, the nature and proportions of which depend on the conditions under which the interaction occurs. Analysis of the plots obtained by polarimetric study of chemically modified heparins suggests, for individual substituents groups, an order of importance of carboxylate greater than N-sulphonate greater than N-acetyl greater than O-sulphate for the Ca(2+)-heparin interaction occurring at [Ca2+]/[heparin disaccharide] ratios of less than 0.5. At higher ratios, transitions occur that eventually lead to the formation of a complex in which the stoichiometry of association is 1 Ca2+ ion/heparin disaccharide unit.

Binding Sites↗
PubMed1992

A study of the composition of fish liver and body oil triglycerides.

Silver-ion high-performance liquid chromatography (Ag(+)-HPLC) was used to study the range and variations in molecular species of triglycerides from industrial, retail and laboratory extracted fish oils. These were contrasted with a typical plant oil. Selected fish oils were fractionated and the fatty acid distribution of the fractions determined by gas-liquid chromatography. Fish oils gave a characteristic Ag(+)-HPLC profile, typified by sharp, intense peaks at the start of the chromatogram and broad, multiple nongaussian peaks for the late eluting components. Triglycerides ranging from those that were wholly saturated to those containing 16 double bonds were isolated. Cod (Gadus spp.), saithe (Pollachius virens) and monkfish (Squatina squatina) liver oils gave similar triglyceride profiles. Mackerel (Scomber scombrus), capelin (Mallotus villosus) and herring (Clupea harengus) body oils gave characteristic triglyceride profiles which were associated with high concentrations of 20:1 and 22:1 fatty acids. Only small amounts of these particular triglycerides were observed for menhaden (Brevoortia spp.), South African anchovy (Engraulis capensis) and Indian sardine (Sardinella longiceps) oils, all of which contained minor amounts of these acids. The latter oils contained highly unsaturated triglycerides, whereas only traces of these were noted for the former. Chromatography with Ag(+)-HPLC can be used for the rapid screening of fish oils and for selecting those oils rich in polyunsaturated acids that may be suitable for enrichment. Cottonseed oil gave well-defined and discrete peaks. Similar peaks were observed in the chromatogram of Omega-combination, a mixture of primrose and fish oils. Thus, fish, plant and a mixture of these oils can be readily distinguished.

Chromatography, Gas↗