The commercial agar from New Zealand Pterocladia species

The compositions of a laboratory extracted agar and commercial agar prepared from a mixture of New Zealand Pterocladia species (P. lucida and P. pinnata) are reported. The structure of the commercial agar has been studied by using methylation analysis, and the results, when considered along with the 13C n.m.r. spectrum, show that the polysaccharide has a structure which is close to that of agarose. Less than 1% of the agar is made up of 1,3-linked 6-O-methyl-D-galactopyranosyl residues. After complete acid hydrolysis, only 2% of the total galactose obtained was the L-enan-tiomer. Reaction of the Pterocladia agarose in the presence of the enzyme D-galactose oxidase showed that the 1,3-linked D-galactosyl residues are oxidized even if they occur in an ordered situation within the molecule.

The chemistry of Pinus radiata. VI. The water-soluble galactoglucomannan

The two major components of the water-soluble polysaccharides extracted from the sapwood of Pinus radiata were a galactoglucomannan and an arabinogalactan. The galactoglucomannan had a number average degree of polymerization of approximately 30, and on complete acid hydrolysis it yielded D-mannose, D-galactose and D-glucose in the ratio 4.5 : 1.3 : 1.0. The structural determination of this polysaccharide by methylation analysis and 13C n.m.r. suggested that it is a linear glucomannan with α-D-galactopyranosyl residues as single side units. No evidence could be found of any branches in the polymer, although the possibility of a small degree of branching cannot be dismissed.

THE CHEMICAL NATURE OF THE SUBSTANCES REQUIRED FOR CELL MULTIPLICATION

1. It has been shown that the ash of liver, hemoglobin, and glutathione each exerts a very slight beneficial effect on the growth of sarcomatous fibroblasts of the rat, or on the condition of their cells when cultivated in a synthetic medium. 2. The addition of all three of these substances, or of only glutathione and hemoglobin, to a mixture of casein digest, glycocoll, and nucleic acid gives a medium in which sarcomatous fibroblasts of the rat proliferate for a considerable time as rapidly as in embryo juice. 3. The mixture is not as adequate a nutritive medium as embryo juice, for after a time dead cells are found surrounding the central fragment of the culture, and after several passages the growth becomes thinner. 4. The hypothesis is suggested that glutathione and hemoglobin may function not only by regulating the respiration and oxidation-reduction reactions within the cell, but also by regulating the oxidation-reduction potential of the medium. 5. It is suggested that the failure to obtain growth of fibroblasts in mixtures of amino acids or of the products of complete acid hydrolysis of proteins is in part due to the absence of glutathione, and that this substance is not synthetized by fibroblasts. 6. The growth of normal fibroblasts of the rat is also increased by the addition of the above mentioned substances to a synthetic medium.