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John L. Harwood

Bio: John L. Harwood is an academic researcher from Cardiff University. The author has contributed to research in topics: Lipid metabolism & Fatty acid. The author has an hindex of 60, co-authored 420 publications receiving 16081 citations. Previous affiliations of John L. Harwood include John L. Scott & Spanish National Research Council.


Papers
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TL;DR: Experiments in vitro showed that elevated Cu 2+ increased the relative labelling of lipids from [ 14 C]acetate without altering total uptake and an alteration in the pattern of fatty acids synthesised was seen in Fucus spp.

15 citations

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TL;DR: CTP:cholinephosphate cytidylyltransferase (EC 2.7.15) was purified from pea stems and was found to have a pH optimum of 7.5, a requirement for Mg 2+ and an M r of 56000.

15 citations

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TL;DR: It is demonstrated that there is no relationship between Dialysate phospholipid levels and the adequacy of filtration, although it corroborates previous reports of an inverse correlation between time on CAPD and dialysate lipid concentrations.
Abstract: A qualitative and quantitative study was undertaken to determine the lipid composition of dialysate effluent from patients maintained on continuous ambulatory peritoneal dialysis (CAPD). Effluent, after a 4-h, 2.27% dextrose dwell, was collected on ice, centrifuged and extracted for lipids with chloroform and methanol. Lipids were separated and identified by thin layer chromatography, and the constituent fatty acids were quantitated by gas liquid chromatography. Effluents from 10 patients were assayed at the commencement of CAPD treatment and again after 6 months of therapy. There was a significant fall in phosphatidylcholine and phospholipid concentrations (P

15 citations

Journal ArticleDOI
TL;DR: The ability of oxygen to induce oleate desaturase independently of temperature in this lower eukaryotic animal model is of novel intrinsic interest, as well as being important for the design of future experiments to determine the molecular mechanism of temperature adaptation in poikilotherms.
Abstract: Induction of fatty acid desaturation is very important for the temperature adaptation of poikilotherms. However, in oxygen-limited late-exponential-phase Acanthamoeba castellanii cultures, oxygen alone was able to induce increased activity of a fatty acid desaturase that converts oleate into linoleate and which has been implicated in the temperature adaptation of this organism. Experiments with [Delta]10-nonadecenoate showed that the enzyme is an n-6 desaturase rather than a [Delta]12-desaturase. It also used preferentially 1-acyl-2-oleoyl-phosphatidylcholine as substrate and NAD(P)H as electron donor. The involvement of cytochrome b5 as an intermediate electron carrier was shown by difference spectra measurements and anti-(cytochrome b5) antibody experiments. Of the three protein components of the desaturase complex, oxygen only increased the activity of the terminal (cyanide-sensitive) protein during n-6 desaturase induction. The induction of this terminal protein paralleled well the increase in overall oleate n-6 desaturation. The ability of oxygen to induce oleate desaturase independently of temperature in this lower eukaryotic animal model is of novel intrinsic interest, as well as being important for the design of future experiments to determine the molecular mechanism of temperature adaptation in poikilotherms.

14 citations

Journal Article
TL;DR: Both the surface tension and biochemical estimations on a control group of rats suggest that there is an increase in the amount of surfactant in the lungs up to about 12 months of age.
Abstract: When rats breathed air containing approximately 70 mg m-3 of respirable crystalline silica 7 h daily for 10 days (2000 mg m-3 h) the surface tension forces of the alveolar lining film were reduced This was shown both by surface tension measurements on lung extracts and by pressure-volume studies with air and saline filling of excised lungs Larger quantities of inhaled silica produced similar effects Chrysotile inhalation caused an even more marked decrease in the surface tension forces In the chrysotile studies these findings were supported by biochemical estimations of the quantity of surfactant in the lungs, which was increased 10-fold by an inhalation of 6500 mg m-3 h Electron microscopy showed an increased number of the type II alveolar cells which produce surfactant and of free phospholipid lattices in the air spaces of the lungs of rats exposed to chrysotile and silica Both the surface tension and biochemical estimations on a control group of rats suggest that there is an increase in the amount of surfactant in the lungs up to about 12 months of age

14 citations


Cited by
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Journal ArticleDOI
Yusuf Chisti1
TL;DR: As demonstrated here, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels.

9,030 citations

Journal ArticleDOI
TL;DR: In this article, the transesterification reaction is aected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats.

4,902 citations

Journal ArticleDOI
TL;DR: The current understanding of IFN‐γ ligand, receptor, ignal transduction, and cellular effects with a focus on macrophage responses and to a lesser extent, responses from other cell types that influence macrophages function during infection are reviewed.
Abstract: Interferon-gamma (IFN-gamma) coordinates a diverse array of cellular programs through transcriptional regulation of immunologically relevant genes. This article reviews the current understanding of IFN-gamma ligand, receptor, signal transduction, and cellular effects with a focus on macrophage responses and to a lesser extent, responses from other cell types that influence macrophage function during infection. The current model for IFN-gamma signal transduction is discussed, as well as signal regulation and factors conferring signal specificity. Cellular effects of IFN-gamma are described, including up-regulation of pathogen recognition, antigen processing and presentation, the antiviral state, inhibition of cellular proliferation and effects on apoptosis, activation of microbicidal effector functions, immunomodulation, and leukocyte trafficking. In addition, integration of signaling and response with other cytokines and pathogen-associated molecular patterns, such as tumor necrosis factor-alpha, interleukin-4, type I IFNs, and lipopolysaccharide are discussed.

3,589 citations

Journal ArticleDOI
TL;DR: A brief summary of the current knowledge on oleaginous algae and their fatty acid and TAG biosynthesis, algal model systems and genomic approaches to a better understanding of TAG production, and a historical perspective and path forward for microalgae-based biofuel research and commercialization are provided.
Abstract: Microalgae represent an exceptionally diverse but highly specialized group of micro-organisms adapted to various ecological habitats. Many microalgae have the ability to produce substantial amounts (e.g. 20-50% dry cell weight) of triacylglycerols (TAG) as a storage lipid under photo-oxidative stress or other adverse environmental conditions. Fatty acids, the building blocks for TAGs and all other cellular lipids, are synthesized in the chloroplast using a single set of enzymes, of which acetyl CoA carboxylase (ACCase) is key in regulating fatty acid synthesis rates. However, the expression of genes involved in fatty acid synthesis is poorly understood in microalgae. Synthesis and sequestration of TAG into cytosolic lipid bodies appear to be a protective mechanism by which algal cells cope with stress conditions, but little is known about regulation of TAG formation at the molecular and cellular level. While the concept of using microalgae as an alternative and renewable source of lipid-rich biomass feedstock for biofuels has been explored over the past few decades, a scalable, commercially viable system has yet to emerge. Today, the production of algal oil is primarily confined to high-value specialty oils with nutritional value, rather than commodity oils for biofuel. This review provides a brief summary of the current knowledge on oleaginous algae and their fatty acid and TAG biosynthesis, algal model systems and genomic approaches to a better understanding of TAG production, and a historical perspective and path forward for microalgae-based biofuel research and commercialization.

3,479 citations