Norepinephrine Turnover in the Hypothalamus of Adult Male Rats: Alteration of Circadian Patterns by Semistarvation

Norepinephrine (NE) turnover, as estimated by 3-methoxy-4-hydroxyphenylethyleneglycol concentration, was studied in the mediobasal hypothalamus of control and semistarved adult male rats at eight time points of a 24-h period. The marked circadian periodicity of NE turnover with a peak in the dark phase in control rats is completely suppressed in semistarved rats. The average 24-h concentration of the NE precursor tyrosine in brain and of tyrosine flow into brain (calculated from plasma amino acid concentrations) is reduced in semistarved rats, but both brain tyrosine and tyrosine flow show continuing circadian fluctuations.     

Distribution of alkanes and fatty acids in theCondalia montana (Rhamnaceae) species complex

The alkane and fatty acid composition of the lipid extracts from leaves of 14 populations ofCondalia: C. microphylla f.xanthocarpa, C. microphylla f.erythrocarpa, C. microphylla f.melanocarpa, C. montana, andC. buxifolia, were determined by gas chromatography. Seventeen alkanes and 14 fatty acids were investigated and a predominance of nonacosane, hentriacontane, palmitic and linoleic acids in all species was found.     

Preparation of chloroplast DNA from pea plastids isolated in a medium of high ionic strength

A simple, rapid, and inexpensive method for the preparation and purification of chloroplast DNA (cpDNA) from pea has been developed. The crucial step is the isolation of chloroplasts in a medium of high ionic strength (I congruent equal to 1.40 M). CpDNA from pea prepared according to this method has successfully been used for restriction enzyme mapping, Southern transfers, and cloning.     

Determination of trace levels of fatty acid metal salts by high-performance liquid chromatography with fluorescence prelabeling

A simple method is described for picomole determinations of fatty acid metal salts. Fatty acid salts are directly labeled with 4-bromomethyl-7-methoxycoumarin in the presence of excess ethylenediaminetetraacetic acid tripotassium salt without any solvent extractions. The fluorescence derivatives of fatty acids are separated by reverse-phase high-performance liquid chromatography followed by fluorometric detection. The response of each fatty acid (C8-C18) calcium salt is linear from 1 to 50 micrograms/ml of samples. The detection limit is about 7 pmol. Good recoveries are obtained for the calcium salts of myrystic acid and soap (C8-C18, C18:1,2). The new method is successfully applied to the study on biodegradation of fatty acids in river water.     

Growth of ectomycorrhizal fungi stimulated by lipids from a pine root exudate

Summary The content of fatty acids was analysed in an exudate from roots of pine seedlings grown axenically in vermiculite with a synthetic nutrient medium. The dominating fatty acdis were fewer in the exudate than in the roots. Unsaturated fatty acids were predominant. The total lipid fraction of the exudate promoted mycelial growth in two of the three ectomycorrhizal fungi tested.     

Application of polyethyleneimine cellulose for the class separation of steroidal carboxylic acids from neutral steroids and pigments in urine

Metabolites of corticosteroids that contain the 21-oic acid moiety are found in human urine. The acids from neutral steroids and urinary pigments have been separated by passing the mixture through a column of polyethyleneimine cellulose. The acids adhering to the column are quantitatively eluted with dilute formic acid. The purified preparation is suitable for derivatization and chromatographic analysis.