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A new family of surfactants, aminimides, has been screened forin vitro antimicrobial activity. These compounds are active against both bacteria and yeast, activity being a function of chain length. Maximum activity for acetimide and acrylimide amine derivatives was extablished with chain lengths of C14–C16. Homologous compounds with lower or higher chain lengths were less active. While showing low antimicrobial activity against gram negative bacteria, mixtures containing C12 and C16 gave good activity against gram negative strains without losing gram positive activity. Aminimides gave low acute LD50’s (200–400 mg/kg) when tested in mice by intraperitoneal injection.

The LD50 oral ingestion values for the common commercial fatty acids are in the range which are considered nontoxic; 24 hour primary skin irritation is considered positive for octanoic acid but negative for decanoic acid and upwards; 4 hour skin corrosivity is considered positive for decanoic acid and lower, negative for lauric acid and higher; eye irritation is considered positive for lauric acid and lower, negative for myristic acid and higher. Among the fatty acid derivatives that have well recognized bacteriocidal and fungicidal properties are undecanoic acid and its salts, sodium and zinc particularly, (athlete’s foot fungus), fatty amine quaternary salts, (general bacteriocide properties), fatty amide derivatives, and sodium salts of common fatty acids. The highly purified monoglyceride prepared from high C-12 fatty acid has unprecedented activity and sanitizing properties.

SummaryMouse brains were extracted with a variety of solutions composed of inorganic salts, organic solvents, or mixtures of each. During these experiments, it was noted that a differential effect of certain salts and solvents on isozyme patterns could be demonstrated. These effects of isozyme systems [lactic dehydrogenase (LDH) and nonspecific esterase] could best be explained on the basis of lipid-enzyme complexes. Circumstantial evidence is provided for viewing LDH as a lipoprotein catalyst.

The structural relationships of 30 straight-chain fatty acids and derivatives and their bactericidal properties were studied with 8 gram-negative and 12 grampositive organisms. Chain length, unsaturation ( cis, trans ), and functional group were all variables considered in this study. Our data indicate that C 12 (lauric acid) is the most inhibitory saturated fatty acid against gram-positive organisms. Monoenoic acid (C 18:1 ) was more inhibitory than saturated fatty acid, but was less active than dienoic derivatives (C 18:2 ). Other unsaturated compounds were less active than C 18:2 . Alcohols and glyceryl esters were active only against gram-positive organisms. In general, esterification of the carboxyl group led to a compound which was less active; monoglycerides were the sole exception. Amine derivatives, contrary to results with fatty acids, esters, and amides, showed activity against both gram-positive and gram-negative organisms.

A broth dilution method was used to determine the minimal inhibitory concentration of a series of fatty acid esters of polyhydric alcohols against gram-negative and gram-positive organisms. Gram-negative organisms were not affected. Gram-positive organisms were inhibited as follows. Of the monoglycerol esters, monoglycerol laurate was the most active. Esters of polyglycerols (tri-, hexa-, and decaglycerol esters) were generally active when the fatty acid had chain lengths of 8 to 12 carbon atoms. Sucrose esters, when active, except for laurate, are more active than the free fatty acid. The spectrum of antimicrobial action of esters of polyhydric alcohols is narrower when compared with the free acids.

The newest member of the aminimide family of surfactants was screened for antimicrobial activity. The present report supports past conclusions that chain lengths of C14 or C16 gave maximum activity to the aminimide derivative. When a number of hexadecane compounds with different polar groups were compared, the aminimide exhibited wide spectrum antimicrobial activity. Although the functional group was important, the length and character of the acyl chain also help to determine antimicrobial activity. A new amide antibiotic, Cerulenin, with a 4-keto-2-enyl chain, was more active than the unsaturated isomer. Thus, both the functional grup as well as the chain length contribute to biocidal activity.

Dietary lipids, in particular unsaturated fat, promote the development of many experimental tumors. However, no mechanisms to fully explain these effects have been elucidated. Recent reports, which we summarize here, suggest a role for gap junction-mediated intercellular communication in the process of tumor promotion. We also review tumor-promoting effects of dietary fat on experimental, particularly mammary, carcinogenesis. Our main focus is to review recent data examining the inhibitory effects of unsaturated fatty acids on metabolic cooperation in Chinese hamster V79 cells. These data suggest that inhibition of junctional communication may be involved mechanistically in the promotion of tumors by high levels of dietary unsaturated fat. Finally, potential mechanisms by which unsaturated fatty acids inhibit metabolic cooperation are examined.

Aminimides are a new class of surface active agents which have antimicrobial activity. These bipolar compounds have activity against both gran-positive and yeast organisms. Their activity against gram-negative organisms is low or absent. The acyl derivatives tested showed maximum activity at chain lengths of C14 and C16. Fatty acid derivatives, shorter ( C16), were less active. Unsaturation was an important factor contributing to aminimide activity. Their low toxicity and wide spectrum of antimicrobial activity make aminimides ideal candidates for further investigation.

Aminimides, a new class of surfactants, have been screened for in vitro antimicrobial activity. Greatest activity against gram (+) and yeast organisms is achieved when a chain length of C16 is reached. This generalization is true whether or not the chain length is joined to the imide or amine group. The type of functional group associated with the surfactant is less important than chain length. Gram (-) organisms do not fit this generalization, since shorter (

The incorporation of 1-(14)C-Acetate into tissue cholesterol of the baboon was measured. Using this indicator gray matter of the cerebrum indicated greater metabolic activity than did white matter.Other tissues besides neural tissue were examined. The peak of radioactivity occurred between 3 and 4 hr. The highest incorporation of radioactivity was measured in the adrenal gland. Liver, spleen and kidney values were of intermediate order.

Glucose-1 and glucose-6 labeled with tritium or carbon-14 were incorporated in vivo into brain and liver sterol. Differential incorporations of glucose labeled in both positions were compared. A higher than expected incorporation of C-1 from glucose was noted.

Contrary to the limited effects of alkyl amides and their corresponding N -derivatives, alkyl amines affected both gram-positive and gram-negative organisms. As with other alkyl derivatives the most sensitive gram-negative bacteria were usually more resistant than the most resistant gram-positive bacteria. Compounds with a chain-length of 11 to 15 are most active. Although some of the general properties relating the activity of fatty acids to their antimicrobial action are similar to those of amine compounds, the amines are unique in that monounsaturation does not increase compound activity. The possible modes of action of these compounds are discussed.

By the application of the isotope derivative technique with radioactive methanol, a procedure for measuring esterified and nonesterified fatty acids was devised. The present method is ideally suited to measuring large numbers of biological samples when total fatty acid content is required. The wide range of sample size, short time required for measurement, applicability to both free and esterified fatty acids, and possibility of computorized data processing make the present method a valuable supplement to gasliquid chromatography.

The appearance of methyl esters of fatty acids in lipid extracts was studied. Experimental evidence indicates that these esters are both natural components of tissues as well as products of technical manipulation. Effect of temperature on the latter process was studied. The results of these experiments show that the post-mortem increase of fatty acid methyl esters could best be explained by postulating an enzymatic rather than a chemical process.

During the past decade, our laboratory has been involved in studying the biosynthesis of brain cholesterol under various conditions. As a result of these studies, we feel that the hypothesis of metabolic stability of cholesterol in adult life is untenable. Our data suggest that there are several compartments of sterol metabolism ranging from extremely fast to metabolically very slow. It is our hypothesis that (a) brain function is more nearly associated with fast turnover compartments than with metabolically slow ones; (b) these compartments can be altered by a variety of stress conditions.