Quantitative estimation of sialic acids. II. A colorimetric resorcinol-hydrochloric acid method.

Method for the determination of hexosamines in tissues.

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

The Determination of Nucleic Acids

Fractionation and characterization of a cyclic adenine ribonucleotide formed by tissue particles

A new spectrophotometric method for the detection and determination of keto sugars and trioses

A spectrophotometric method for the microdetermination of hexosamines.

A new color reaction for the determination of aldopentose in presence of other saccharides.

Changes in the lens of aged humans and animals are among the most conspicuous symptoms of the aging process in the animal body. They can be evaluated approximately by measuring changes in the refractive index of the lens. This and two other factors make the lens a particularly favorable object for investigations of the cellular mechanism of aging. The first of these factors is the relative simplicity of the morphological structure of the lens, due to the lack of vessels. The second factor is the apparent simplicity of the chemical composition and the abundance of the protein in the lens fibers. Two changes in the chemical composition of the lens with advancing age have long been recognized and studied: (1) the continuous loss of water in the lens, first investigated systematically by Burger and Schlomka 1 (1927) and by Salit, 2 and (2) the progressive accumulation, observed as far back

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Ellen Borenfreund

Papers

A new spectrophotometric method for the detection and determination of keto sugars and trioses

A spectrophotometric method for the microdetermination of hexosamines.

A new color reaction for the determination of aldopentose in presence of other saccharides.

Changes in lens proteins of rats during aging.

A specific color reaction of glycolic aldehyde.