Evidence that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects. II. Lymphoma 6C3HED cells cultured in a medium devoid of L-asparagine lose their susceptibility to the effects of guinea pig serum in vivo

Cells of the original line of lymphoma 6C3HED, which regularly prove susceptible to the effects of guinea pig serum in vivo, were cultured in Eagle's medium devoid of L-asparagine; after a latent period of 2 or more weeks, during which time the cell population declined markedly, some of the cells began to proliferate, and thereafter continued vigorous growth. On implantation into mice the proliferating cells were found, however, to have completely and permanently lost their susceptibility to the effects of guinea pig serum. By contrast, when cultures of the original line of 6C3HED cells were prepared in Eagle's medium to which L-asparagine was added in a concentration of 20.0 mg/liter or more, they proliferated vigorously from the beginning; after long periods of growth in the enriched medium in vitro they remained susceptible to the effects of guinea pig serum upon test in vivo. Other amino acids, purines, and pyrimidines were unable to substitute for L-asparagine in this relation. Furthermore, a variant subline of 6C3HED cells which had become insensitive to guinea pig serum under in vivo conditions did not require L-asparagine for growth in tissue culture. It seems plain from the findings as a whole, that in 6C3HED cells, L-asparagine dependence in vitro is associated with the in vivo character of guinea pig serum sensitivity, and conversely L-asparagine independent variants are insusceptible to the effects of guinea pig serum. The implications of the findings complement those of a companion paper in which direct evidence is provided that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects.

Evidence that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects. I. Properties of the L-asparaginase of guinea pig serum in relation to those of the antilymphoma substance

A number of the properties of the L-asparaginase present in guinea pig serum have been examined and shown to be indistinguishable from those of the agent responsible for inhibiting cells of lymphoma 6C3HED in vivo. The patterns of instability of the enzyme to changes in temperature and pH were found to parallel closely those of the antilymphoma agent. L-Asparaginase activity was essentially absent from the serum of newborn guinea pigs and this failed to inhibit 6C3HED cells. On separating guinea pig serum proteins by salt precipitation, electrophoresis, and chromatography on DEAE cellulose, antilymphoma activity was found only in fractions which contained L-asparaginase.

ABSORPTION AND FLUORESCENCE OF WATER-SOLUBLE PIGMENTS PRODUCED BY FOUR SPECIES OF PSEUDOMONAS

Pigments produced by four species of Pseudomonas during growth in three media were examined for visible and ultraviolet absorption. Ultraviolet fluorescence excitation and emission spectra were obtained. In all pigments, an absorption maximum occurs at 405 mmu. Ultraviolet excitation of fluorescence occurs primarily at 400 to 410 mmu, with smaller maxima at 460 mmu, or 525 mmu, depending on pH, bacterial species, or medium. Emission maxima, after excitation at 410 mmu, occur at 390 mmu, and 455 to 475 mmu. The differences in fluorescence spectra may be used for taxonomic classification of the Pseudomonas.

QUANTITATIVE COMPARISON BETWEEN OXYTOCIN AND FOUR RELATED NEUROHYPOPSIAL PEPTIDES ON THE HUMAN UTERUS IN SITU

Quantitative assays of four synthetic peptides related to oxytocin were carried out on the post partum human uterus in vivo by means of external tocography. The following activities (U/mg, means and standard errors) were found: isoleucine(8)-oxytocin 365+/-70, asparagine(4)-oxytocin 150+/-40, desamino(1)-oxytocin 1,030+/-300, serine(4)-isoleucine(8)-oxytocin 335+/-95. None of the conventional bioassay procedures proved to be fully reliable for predicting the oxytocic activity in man of peptides related to oxytocin. If the tocographically recorded effects of equipotent doses of the compounds are compared with those of oxytocin no qualitative differences can be observed.

NUTRITIONAL STUDIES OF DEVELOPMENT IN SCHIZOPHYLLIUM COMMUNE

Niederpruem, Donald J. (Indiana University Medical Center, Indianapolis), Hudner Hobbs, and Lyle Henry. Nutritional studies of development in Schizophyllum commune. J. Bacteriol. 88:1721-1729. 1964.-Individual carbon and nitrogen sources which sustain dikaryotic fruiting in the basidiomycete Schizophyllum commune were determined. Combination studies indicated that certain poor substrates were inhibitory; these included acetate, citrate, KNO(2), and l-lysine. Homokaryotic (haploid) fruiting was promoted by dilute culture medium. Both developmental systems were arrested by respiratory CO(2). Elevated temperature (e.g., 30 C) essentially completely blocked homokaryotic fruiting of S. commune.

UPTAKE OF FREE PLASMA AMINO ACIDS BY THE LACTATING COW'S UDDER AND AMINO ACID COMPOSITION OF UDDER LYMPH

1. Total alpha-amino N and the amounts of 24 ninhydrin-positive substances were determined in several samples of plasma and lymph from the cow's udder. The arteriovenous differences of these substances across the mammary glands were measured in several experiments performed on lactating cows and in one experiment on a ;dry' cow. Udder lymph obtained from live lactating cows by a lymph fistula and taken after killing lactating cows was analysed. 2. The concentrations of the individual free amino acids in udder lymph obtained from the live cow were similar to those found in cow's plasma. The concentrations of many amino acids in udder lymph taken immediately after death were two- to four-fold higher than those of the corresponding amino acids in udder lymph obtained from the live cow. 3. Most amino acids of the blood showed a considerable decrease in concentration by passage across the lactating mammary gland. Ornithine, a non-casein amino acid, showed arteriovenous differences of up to 60% of the arterial plasma concentration. No substantial amino acid uptake by the udder could be demonstrated in the experiment on the non-lactating cow. 4. The arteriovenous differences obtained for arginine, glutamine, isoleucine, leucine, lysine, valine, threonine and histidine were probably large enough to provide all the respective amino acid residues in milk protein. 5. The uptake of aspartic acid, asparagine, glutamic acid, serine and proline by the lactating cow's udder was not sufficient to account for all these respective amino acid residues found in milk protein.

AMINO GROUP FORMATION AND GLUTAMATE SYNTHESIS IN STREPTOCOCCUS BOVIS

Burchall, J. J. (University of Illinois, Urbana), R. A. Niederman, and M. J. Wolin. Amino group formation and glutamate synthesis in Streptococcus bovis. J. Bacteriol. 88:1038-1044. 1964.-Extracts of Streptococcus bovis grown on NH(4) (+) as a nitrogen source contain a nicotinamide adenine dinucleotide phosphate (NADP)-linked glutamic dehydrogenase and are devoid of alanine dehydrogenase, other amino acid dehydrohygenases, and aspartase. A potential source of reduced nicotinamide adenine dinucleotide phosphate for glutamate synthesis is a NADP and nicotinamide adenine dinucleotide (NAD)-linked glyceraldehyde-3-phosphate dehydrogenase present in the extracts. Experiments with C(14)-labeled glucose and NaHCO(3) indicate that the glutamate carbon skeleton is synthesized by a tricarboxylic acid pathway. The synthesis of the carbon skeleton of glutamate is repressed when glutamate or casein hydrolysate supplement the NH(4) (+)-containing growth medium. Repression of glutamic dehydrogenase and a NAD-linked isocitric dehydrogenase occurs only when complex nitrogen sources, but not when free amino acids, are added to the growth medium.