Showing papers by "John L. Harwood published in 1975"
TL;DR: Pulmonary surfactants from ox, rabbit, rat and sheep were isolated and analysed; their overall composition were high in hydrophobic amino acid residues and Hexadecanoic acid was the principal fatty acid.
Abstract: 1. Pulmonary surfactants from ox, rabbit, rat and sheep were isolated and analysed. 2. All preparations had a high anenoic phosphatidylcholine content and would produce stable surface tensions of 0.01 Nm-1 or less. 3. Protein content was 8-18% of the dry weights. A number of proteins were observed; their overall composition were high in hydrophobic amino acid residues. 4. Lipid content varied from 79% (ox) to 90% (rabbit) with phosphatidylcholine representing from 58% (sheep) to 83% (rabbit) of the total lipid. The surfactant preparations were rather similar in lipid composition except that sheep surfactant contained about 10% lysophosphatidylcholine. 5. Hexadecanoic acid was the principal fatty acid. It was particularly high in phosphatidylcholine. 6. Phosphatidylglycerol was a minor constituent of all surfactants but phosphatidyldimethylethanolamine was not detected.
79 citations
TL;DR: Lipid content and changes during the first 2 days of germination have been examined in soya bean Glycine max (L.) Merr variety Fiskeby V. Triacylglycerols had low specific radioactivities and, of the phospholipids, phosphatidylglycerol, cardiolipin, and phosph atidylinositol had the highest specificRadioactivities.
38 citations
TL;DR: The rate of fatty acid synthesis by isolated chloroplasts paralleled the changes in endogenous trans-3-hexadecenoic acid levels in the leaves from which they were isolated, and arsenite addition inhibited stearate formation by isolatedchloroplasts but resulted in a two-fold stimulation of overall synthesis.
Abstract: 1
Broad bean (Vicia faba) leaves contain rather high concentrations (about 4% of total fatty acids) of the trans-3-hexadecenoic acid.
2
Amounts of the acid increase with the age of the leaves and are absent from etiolated tissue.
3
Changes in the levels of trans-Δ3-hexadecenoic acid can be produced by subjecting the intact plants to various light/dark periods.
4
Chloroplasts isolated from broad-bean leaves show high rates of fatty acid synthesis from [1-14C]acetate. Synthesis is dependent on coenzyme A and ATP but is insensitive to the addition of exogenous acyl carrier protein.
5
The pattern of acids made includes about 20% palmitic, 5% hexadecenoic, 10% stearic and 60% oleic. trans-3-Hexadecenoic acid synthesis was most active in chloroplasts from plants exposed to the dark for 5 days and light for 3 days.
6
Arsenite addition inhibited stearate formation by isolated chloroplasts but resulted in a two-fold stimulation of overall synthesis.
7
The rate of fatty acid synthesis by isolated chloroplasts paralleled the changes in endogenous trans-3-hexadecenoic acid levels in the leaves from which they were isolated.
31 citations
TL;DR: The results indicate that sulphoquinovosyl diacylgylcerol synthesis in alfalfa probably proceeds by a pathway similar to that in Euglena.
23 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