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[
Comparative Biochemistry and Physiology,
1963]
1. The free-living nematode, Caenorhabditis briggsae, after incubation with various radioactive substrates, excretes nitrogen chiefly in the form of ammonia and amino acids. No significant amounts of urea, uric acid, allantoin or creatinine are produced. 2. Highly radioactive acidic and neutral components are excreted into the incubation media. 3. The results obtained are in general agreement with the known excretion products of a number of parasitic
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[
Science,
1968]
The free-living, hermaphroditic nematode Caenorhabditis briggsae has a nutritional requirement for sterols. It will reproduce indefinitely in a liquid medium containing only bacterial cells (Escherichia coli) and salts if various sterols are present. Several other lipid-soluble materials are ineffective in supporting reproduction.
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[
Comparative Biochemistry and Physiology,
1969]
1. The free-living nematode, Caenorhabditis briggsae, excretes labeled glycerol as a major product when incubated with acetate-14C in "whole medium". 2. When incubated in water of buffer solution, little or no glycerol is formed, glucose and trehalose being the major products. 3. Turbatrix aceti yields similar results. Panagrellus redivivus shows similar behavior when incubated in water, but in "whole medium" other neutral products, presumably sugars, are formed, in addition to glycerol.
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[
Comparative Biochemistry and Physiology,
1966]
1. The presence of malate synthetase has been demonstrated in the four small free-living nematodes, Caenorhabditis briggsae, Panagrellus redivivus, Rhabditis anomala and Turbatrix aceti. Since the organisms possess isocitrate lyase, the complete glyoxalate cycle appears to be present. 2. A sensitive procedure for the detection of labeled malate has been employed to confirm unequivocally the presence of this acid as a product of malate synthetase.
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[
Biochim Biophys Acta,
1961]
We wish to report what we believe to be the first demonstration of the biosynthesis of "essential amino acids" by a multicellular animal species. Axenic cultures of Caenorhabditis briggsae, a small free-living nematode, were grown at 20C in a chemically defined medium supplemented with a heated liver extract. The amino acid moiety of the medium was replaced with soy-peptone. After two weeks, protein which precipitated was solubilized by treatment of the medium with trypsin for approx. 20 h and the worms were then isolated by centrifugation under sterile conditions.......
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[
Biochim Biophys Acta,
1962]
Axenic cultures of the free-living nematode, Caenorhabditis briggsae, were incubated in water for 6 days in the presence of [1-14C]acetate, [2-14C]acetate, [1-14C]glucose and [2-14C]glycine, respectively. From the last three substrates the worms were found to biosynthesize not only the "non-essential" amino acids represented by glutamic acid, aspartic acid, alanine, glycine, serine and arginine, but also the "essential" amino acids, threonine, tyrosine, valine, leucine, isoleucine, histidine and lysine. This appears to be the first report of such syntheses in an animal species.
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[
Comparative Biochemistry and Physiology,
1968]
1. Under axenic conditions, the free-living nematodes, Caenorhabditis briggsae, Turbatrix aceti and Panagrellus redivivus, are unable to synthesize cholesterol from acetate-2-C14 or DL-mevalonate-2-C14. 2. No evidence could be found that sterols other than cholesterol are synthesized by any of the organisms.
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[
Arch Biochem Biophys,
1964]
The small, free-living nematode, Caenorhabditis briggsae, converts aspartic
acid-4-C14 to labeled glycine. Evidence is presented which suggests that the mechanism for this conversion involves the formation of isocitrate and its subsequent splitting by isocitrate lyase to yield glyoxalate and hence, glycine. In support of this mechanism, the enzyme "isocitrate lyase" has been demonstrated in sonic extracts of C. briggsae.
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[
Comparative Biochemistry and Physiology,
1965]
1. Formate-C14 is readily incorporated into serine by Caenorhabditis briggsae, presumably by a one-carbon addition to glycine. The reverse reaction (conversion of serine to glycine) appears to take place only to a limited degree. The formate-carbon is also incorporated into glutamate, aspartate and alanine. 2. C(14)O(2) is incorporated, as expected, into the amino acids related to the tricarboxylic acid cycle, probably by way of C02 fixation via malic enzyme. A number of unidentified radioactive acids were also formed, suggesting the existence of additional metabolic pathways. 3. Other findings demonstrated the production of glutamine and asparagine in the incubation medium of worms fed acetate-2-C14; the identification of y-aminobutyric acid in the worms; the conversion of phenylalanine to tryosine, and the inability of the worms to form taurine from labeled acetate or methionine. 4. Products found in the incubation medium of C. briggsae depend upon the substrate and show a direct metabolic relationship to the latter.
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[
International Journal of Biochemistry,
1970]
1. The free-living nematodes, Caenorhabditis briggsae and Panagrellus redivivus, are capable of synthesizing polyunsaturated fatty acids de novo. Acetate-2-14C yields labelled linoleic acid (18:2), linolenic acid (18:3), and C20 fatty acids with up to 5 double bonds. Evidence is presented which shows that these acids are labelled throughout the chain and not formed by simple addition of a labelled 2-carbon unit to pre-existing precursors. 2. Stearate-1-14C and oleate-1-14C are also converted directly to polyunsaturated fatty acids in C. briggsae, providing further proof that oleate can be desaturated to linoleate. Of all the multicellular animals studied so far, only free-living nematodes have this biosynthetic capability.