About
63
Publications
5,511
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,674
Citations
Publications
Publications (63)
We examined Hg(II) bioaccumulation and compartmentalization patterns in conjunction with antioxidant responses in four aquatic insect species: two caddisflies (Chimarra sp. and Hydropsyche betteni) and two mayflies (Maccaffertium modestum and Isonychia sp). Total antioxidant capabilities differed among unexposed larvae, with both caddisfly species...
Systems biology is an approach to dissection of complex traits that explicitly recognizes the impact of genetic, physiological and environmental interactions in the generation of phenotypic variation. We describe comprehensive transcriptional and metabolic profiling in Drosophila melanogaster across four diets, finding little overlap in modular arc...
Purple-fleshed sweetpotatoes (PFSP) can be a healthy food choice for consumers and a potential source for natural food colorants. This study aimed to identify anthocyanins and anthocyanidins in PFSP, and to evaluate the effect of thermal processing on these polyphenolic compounds. Freeze-dried powder of raw and steamed samples of three PFSP varieti...
We examined Hg(II) bioaccumulation and compartmentalization patterns in conjunction with antioxidant responses in four aquatic insect species: two caddisflies (Chimarra sp. and Hydropsyche betteni) and two mayflies (Maccaffertium modestum and Isonychia sp). Total antioxidant capabilities differed among unexposed larvae, with both caddisfly species...
Introduction Methods Diagnostics and Functional Genomics Metabolomics and Toxicology Suggested Reading
The detection by electron paramagnetic resonance (EPR) spectroscopy of free radical centres trapped in cellulosic materials has been proposed as a potential method for the identification of irradiated foodstuffs of plant origin. However, the published spectra of irradiated cellulose show distinct differences from those obtained from unpurified cell...
Although most genetic association studies are performed with the intention of detecting nucleotide polymorphisms that are correlated with a complex trait, transcript abundance should also be expected to associate with diseases or phenotypes. We performed a scan for such quantitative trait transcripts in adult female heads of the fruit fly (Drosophi...
Optimization of the EPR signal from the ‘cellulosic’ radical of irradiated plant materials can be achieved with an incident microwave power of approximately 250 μW. This is lower than previously recommended (0.5–2.0 mW) and results in signal intensities of up to 200% greater amplitude. the use of this recommended power in any future EPR-based detec...
Patterns of variation for the solanidine-based glycoalkaloids have been determined for tuber material of genebank accessions of landraces of the cultivated potato and three closely-related wild species. Total levels were low in the cultivated taxa investigated,S. phureja, S. stenotomum, and the tetraploidS. tuberosum in its two formsS. tuberosum ss...
To study the variation in genistein + daidzein intake over a 6-month period and test the reliability of 24 h urinary isoflavones as a biomarker of exposure over time.
Dietary genistein + daidzein intake was assessed at various time points throughout six months in 15 healthy subjects. Group 1 (n=8) followed nonsupplemented diets and Group 2 (n=7) to...
Background
The current study assessed the value of spot urine and plasma samples as biomarkers of phyto-oestrogen exposure.
DesignTwenty-one subjects, aged 21–76 (9 males and 12 females) completed the five-week intervention study. They provided spot urine and plasma samples at the start of the study, weekly samples for four weeks while eating a da...
Estimating intake of phyto-oestrogens (PO) is difficult because there is inadequate information on the PO content of foods. Development of a biomarker of intake is therefore necessary for carrying out epidemiological studies. We aimed to validate a newly constructed PO database, containing more than 600 values assigned to foods by using duplicate d...
Several markers of oxidative processes have been measured in leaves of Phaseolus vulgalis infected with Botrytis cinerea, with the specific objective of investigating changes induced by this necrotrophic pathogen in tissue remote from the lesion. There was a progressive decrease with time in the contents of ascorbic acid (AA) in apparently healthy...
Infection of leaves of Arabidopsis thaliana with conidial suspensions of the necrotrophic pathogen Botrytis cinerea resulted in a large decrease in the level of ascorbic acid and increases in intensity of a single‐peak free radical and Fe(III)
(g=4.27) signals in electron paramagnetic resonance (EPR) spectra. These changes were not confined to the...
Leaf-surface extracts prepared from 18 non-cultivated (wild) plant species, derived from the Capparidaceae, Cruciferae, Resedaceae and Tropaeolaceae were ranked for their ability to stimulate oviposition by the cabbage root fly, and analysed for glucosinolates. A total of 28 different glucosinolates were identified. A clear relationship was detecte...
- The fungal metabolite botrydial was detected for the first time in ripe fruits of sweet pepper (Capsicum annuum) wound-inoculated with conidial suspensions of Botrytis cinerea and also in leaves of Phaseolus vulgaris and Arabidopsis thaliana inoculated without wounding. This phytotoxin was produced in soft rot regions of the infection. In C. annu...
The oxidation of linoleic acid by soybean lipoxygenase-1 (LOX-1) was inhibited in a time-dependent manner by 4-hydroxy-2(E)-nonenal (HNE). Kinetic analysis indicated the effect was due to slow-binding inhibition conforming to an affinity labeling mechanism-based inhibition. After 25 min of preincubation of LOX-1 with and without HNE, Lineweaver-Bur...
A method using liquid chromatography - atmospheric pressure chemical ionisation mass spectrometry was evaluated for determining the molecular species composition of phospholipids (phosphatidylcholines from soybean, egg yolk and bovine liver) after conversion to diacylglycerol nicotinate derivatives. The structures could be deduced from pseudo-molec...
The role of active oxygen species has been studied in spreading soft-rot lesions caused by the necrotrophic fungal pathogen Botrytis cinerea Pers.:Fr. in leaves of four genotypes of French bean (Phaseolus vulgaris L.). Large increases were observed for the aldehydic end-products of oxidative damage, malondialdehyde and 4-hydroxy-2-nonenal, as a res...
Free radical adducts of the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone have been observed by electron paramagnetic resonance spectroscopy in detached fruits of Capsicum annuum investigated 5 days after infection with Botrytis cinerea. The spectra of these adducts were at a maximum within the soft rot lesion, but they could also be dete...
The antioxidative capacities of a number of Rubus species of varied pigmentation have been investigated. In addition, total phenol, anthocyanin and ascorbic acid contents have been determined. Two methods to assess the antioxidant potential of fruit juices have been used. The antioxidant capacities of the fruit ranged from 0 to 25.3 µmol Trolox equ...
The use of liquid chromatography–atmospheric pressure chemical ionisation–mass spectrometry has been investigated as a potential method for both the identification and quantification of desulphoglucosinolates. The results indicate that this methodology is particularly useful as a rapid technique for the confirmation of the identity of desulphogluco...
The effect of light exposure on the steroidal glycoalkaloid content of Solanum phureja tubers has been investigated and compared with that in domesticated potato (Solanum tuberosum) tubers. The results indicated that the increase in the concentration of solanidine-based glycoalkaloids, alpha-solanine and alpha-chaconine was broadly similar in both...
The antioxidative capacities of a number of Rubus species of varied pigmentation have been investigated. In addition, total phenol, anthocyanin and ascorbic acid contents have been determined. Two methods to assess the antioxidant potential of fruit juices have been used. The antioxidant capacities of the fruit ranged from 0 to 25.3 mmol Trolox equ...
A combination of electron paramagnetic resonance (EPR) spectroscopy and analytical chemistry has been used to study the changes in free radical content, transition metal ion status and lipid peroxidation following inoculation of fruits of sweet pepper (Capsicum annuum) with Botrytis cinerea. EPR detected a high concentration of an unidentified free...
The purpose of this study was to evaluate the toxicological effects of 4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA) on in vitro plant cells using the model morphogenetic system of Daucus carota L. for the production of somatic embryos. It was found that both HNE and MDA inhibited proliferative growth and embryogenesis in D. carota cultures....
Cell-wall-associated oxidases extracted from the lignifying xylem of Sitka spruce and ash oxidise sinapyl alcohol at a greater rate than coniferyl alcohol and p -coumaryl alcohol (SA > CA > pCA). The enzyme from ash shows a marked preference, on a specific activity basis, for the oxidation of SA over CA and pCA (SA ≫ CA ≥ pCA) and has a particularl...
Oxidase activity was enriched in extracts of the developing, lignifying xylem of Sitka spruce, Leyland cypress, Lawson cypress and Wych elm obtained by a procedure that selects cell-wall-associated glycoproteins. All of the xylem extracts were able to oxidise the monolignol, coniferyl alcohol, and had a greater affinity for coniferyl alcohol than A...
Free radicals produced during the autoxidation of unsaturated edible oils are extremely short-lived, but are able to react with spin traps to produce adducts with sufficient stability for spectroscopic characterisation at (near) cooking temperatures (353–443 K). EPR spectra have shown that the model esters methyl oleate, linoleate and linolenate ea...
The cytologically active secondary lipid peroxidation products, malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE) have been detected as their 2,4-dinitrophenylhydrazone (DNP) derivatives in plant tissue cultures using LC-MS. This paper reports, for the first time, the use of LC-MS methodology to definitively identify 4-hydroxy-2-nonenal in plants...
A range of techniques have been employed to detect and examine aldehydic products of lipid peroxidation in D. carota cultures. Emphasis is placed on the use of HPLC and LC-MS techniques to aid the identification and profiling of aldehydic dinitrophenyl hydrazone (DNPH)-derivatives in dedifferentiated callus tissues. Using these approaches, malondia...
The cytologically active secondary lipid peroxidation products, malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE) have been detected as their 2,4-dinitrophenylhydrazone (DNP) derivatives in plant tissue cultures using LC-MS. This paper reports, for the first time, the use of LC-MS methodology to definitively identify 4-hydroxy-2-nonenal in plants...
Upward trends in allergy and asthma rates have been reported in most western societies, including the UK, where around 15-20% of the population now suffer from allergy or asthma. Scientific proof of the causes of these increases relies on accurate assessment of exposure and standardized diagnostic tests, such as for specific IgE in blood serum and...
The generation of free radical intermediates as a result of the oxidative degradation of lipid molecules during the heating of grape seed oil has been established by a combination of ''spin trapping'' and electron paramagnetic resonance spectroscopy. The effects of temperature on the rates of formation and decomposition of the adduct with the spin...
The generation of free radical intermediates as a result of the oxidative degradation of lipid molecules during the heating of grape seed oil has been established by a combination of spin trapping and electron paramagnetic resonance spectroscopy. The effects of temperature on the rates of formation and decomposition of the adduct with the spin trap...
Instant coffee solutions were shown by electron paramagnetic resonance (EPR) spectroscopy to act as proxidants by enhancing the production of ascorbyl radicals from ascorbic acid. The coffee solutions were also shown to act as scavengers of superoxide radicals in competition with a spin trap. The radical scavenging capabilities of several component...
Iron nitrosyl haemoglobin (HbFeNO) gives well defined ESR spectra, and can be detected at room temperature, in contrast with most transition metal complexes of biological importance. This is because the unpaired electron remains strongly localised on the NO ligand. It is of importance because it proves the formation of nitric oxide, which unfortuna...
Physiological and biochemical studies of seed storage parameters in Carica papaya - Volume 102 - W. Magill, N. Deighton, H. W. Pritchard, E. E. Benson, B. A. Goodman
Synopsis
The deteriorative processes leading to the death of a population, individual or part of an individual can be genetically programmed or induced by environmental perturbations, physical damage, pests and diseases. Senescence in multicellular plants is typically a phenomenon resulting from cell differentiation and loss of totipotency. Recycli...
Changes of the in vitro morphogenetic state may be achieved for some potato genotypes, but others are unresponsive (recalcitrant). Although the biochemical basis for somatic recalcitrance is unknown, evidence suggests that two different aspects of oxidative stress may be involved. Phenolic oxidation is a major problem in manipulating cultures of wo...
Synopsis
The major antioxidants present in the essential (volatile) oils of oregano ( Origanum vulgare , L.), summer savory ( Satureja hortensis , L.) and thyme ( Thymus vulgaris , L.) have been identified as carvacrol and thymol which have both been demonstrated to possess fungicidal and bactericidal properties. EPR spectra produced upon oxidation...
The induction of plant defence mechanisms has been extensively studied in recent years and there appear to be three interdependent roles for free radicals in the host response (Sutherland 1991) viz ; oxidation of specific host components, which may include lipid peroxidation (Rogers et al . 1988) and cell wall lignification (Bolwell et al . 1985),...
1. Electron paramagnetic resonance spectroscopy was used to study free-radical signals in freeze-clamped frozen liver tissue from rats after a 1 year period of dietary supplementation with alcohol, iron, or alcohol and iron. In alcohol-fed, iron-fed and alcohol- and iron-fed animals, mild histological damage was seen on light microscopy and evidenc...
The formation of stable free radicals upon reaction of the essential oils of 10 plant species with ultraviolet radiation and the superoxide radical anion, O2−, has been investigated by electron paramagnetic resonance (EPR) spectroscopy. Only the oils from oregano, summer savory and thyme produced EPR spectra and the results can be accounted for in...
The sale of irradiated food in the UK has been legal since the start of 1991 with the proviso that it must be labelled as such. At present there are no methods sufficiently accurate and reliable for the routine detection of irradiated food of all varieties. The current state of development of different physical, chemical and biological methods avai...
The spin-trapping technique has demonstrated that carbon-centered radicals are produced during soluble-methane-monooxygenase catalysis of the hydroxylation of several different types of substrate. The resulting spin-adducts were identified from the hyperfine splitting constants in their EPR spectra. Isotopic labelling showed unequivocally that the...
The absolute requirement of oxygen for a potato tuber (cv. Pentland Crown) to display a resistant response toErwinia carotovora has been demonstrated in EPR measurements. These show that a relatively stable free radical is formed in inoculated hosts only after exposure to air. In an attempt to isolate and identify unstable free radical precursors,...
Soluble methane monooxygenase from Methylococcus capsulatus(Bath) and Methylosinus trichosporium(OB3b) comprises three proteins that are necessary for the formation of methanol from methane, NADH2 and O2. The reductase (Mr= 38 500) contains an FAD and Fe2S2 centre and passes electrons to the hydroxylase (Mr= 250 000) which contains a bridged diiron...
The major iron-storage proteins, ferritin and haemosiderin, comprise a protein skin which envelops closely packed FeIII largely in the form of iron oxyhydroxide. When fully loaded there can be ca. 4500 iron atoms in ferritin and in haemosiderin, but full loading is rare. The EPR spectra comprise very broad features stretching from near-zero field t...
Carbon-centred radical intermediates have been identified by spin-trapping in the soluble methane monooxygenase catalysed hydroxylation of alkyl substrates.
Summary A low molecular weight complex of an iron oligomer ( M r ~ 1000) has been isolated from rat liver and characterized physically and chemically. The h.p.l.c.-purified material contains the free amino acids glutamate and aspartate. Chemical techniques suggest the iron present in the factor is as iron(III) and is readily donated to high-affinit...
T he process of wood formation Wood is the major renewable resource of timber for building, pulp for papermaking and is the main source of fuel in developing countries 1 . Trees also fix millions of tonnes of carbon dioxide into wood, which locks up this 'greenhouse' gas and influences global tempera-ture control. New wood is formed by an extraordi...