Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.

https://science.sciencemag.org/content/sci/258/5090/1946.full.pdf

Isolation and structure of a brain constituent that binds to the cannabinoid receptor

The measurement of lipid phosphate is proposed as an indicator of microbial biomass in marine and estuarine sediments. This relatively simple assay can be performed on fresh, frozen or frozen-lyophilized sediment samples with chloroform methanol extraction and subsequent phosphate determination. The sedimentary lipid phosphate recovery correlates with the extractible ATP and the rate of DNA synthesis. Pulse-chase experiments show active metabolism of the sedimentary phospholipids. The recovery of added 14C-labeled bacterial lipids from sediments is quantitative. Replicate analyses from a single sediment sample gave a standard deviation of 11%. The lipid extract can be fractionated by relatively simple procedures and the plasmalogen, diacyl phospholipid, phosphonolipid and non-hydrolyzable phospholipid content determined. The relative fatty acid composition can be readily determined by gas-liquid chromatography. The lipid composition can be used to define the microbial community structure. For example, the absence of polyenoic fatty acids indicates minimal contamination with benthic micro-eukaryotes. Therefore the high content of plasmalogen phospholipids in these sediments suggests that the anaerobic prokaryotic Clostridia are found in the aerobic sedimentary horizon. This would require anaerobic microhabitats in the aerated zones.

Determination of the sedimentary microbial biomass by extractible lipid phosphate.

Publisher Summary This chapter discusses the chemical analysis of microbial cells. The preparation of material for analysis is discussed, because changes in the chemical composition of cells may occur as a result of the washing and storage conditions used. Wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values. Selection of an analytical procedure is a subjective process, because the number of suitable methods is large and each will have different merits and defects. Primary considerations are sensitivity, specificity, reproducibility, and absolute accuracy. Automatic methods for performing biochemical analyses, already widely accepted in hospitals and in industry, are beginning to make their way into the research laboratory. All automatic analyzers developed so far may be classified as either “continuous-flow” or “discrete” types. All of them use colorimetric methods exclusively and contain some form of automatic colorimeter for final read-out. The first and best-known is the Technicon “AutoAnalyzer,” which is of the continuous-flow type.

Chapter III Chemical Analysis of Microbial Cells

Effects of ischemia and electroconvulsive shock on free fatty acid pool in the brain.

Chemotaxonomy of aerobic Actinomycetes: Phospholipid composition

[53] Quantitative and qualitative analysis of lipids and lipid components

The Use of Sephadex for the Removal of Nonlipid Contaminants from Lipid Extracts

A comprehensive study of the postnatal changes in the concentration of the lipids of developing rat brain.

A Microanalytical Technique for the Quantitative Determination of Twenty-four Classes of Brain Lipids*

The biochemistry of long-chain, nonisoprenoid hydrocarbons. I. Characterization of the hydrocarbons of Sarcina lutea and the isolation of possible intermediates of biosynthesis.

John C. Dittmer

Papers

[53] Quantitative and qualitative analysis of lipids and lipid components

The Use of Sephadex for the Removal of Nonlipid Contaminants from Lipid Extracts

A comprehensive study of the postnatal changes in the concentration of the lipids of developing rat brain.

A Microanalytical Technique for the Quantitative Determination of Twenty-four Classes of Brain Lipids*

The biochemistry of long-chain, nonisoprenoid hydrocarbons. I. Characterization of the hydrocarbons of Sarcina lutea and the isolation of possible intermediates of biosynthesis.