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[
1980]
The practical use of free-living nematodes for aging studies must overcome two problems. Not only must cultures begin with organisms of a similar age, but also reproduction must be prevented, or synchrony will be lost and the aging cultures will become contaminated with newborn orrganisms and will eventually revert to typical "mixed" cultures. The problem of obtaining uniformly small organisms to start cultures has been solved by the use of screens for Turbatrix aceti and the hatching of isolated egg masses for Caenorhabditis elegans. Subsequent reproduction is prevented by the use of the DNA inhibitor fluorodeoxyuridine, or by culturing the organisms at elevated temperatures. Another practical method for aging of T. aceti is the use of a repeated screening process that periodically removes small (young) organisms from the aging cultures.
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[
Worm Breeder's Gazette,
1977]
Adenosine, at 0.004 M, stimulates growth of cultures of Turbatrix aceti in the absence of nucleotides. At 0.016 M, it is strongly inhibitory. In the case of Caenorhabditis briggsae (a strain of C. elegans?), adenosine at 0.008 M is inhibitory and at 0.016 M, it essentially prevents reproduction. Guanosine has little effect up to 0.002 M. Uridine and cytidine are stimulatory. AMP also effectively inhibits growth of C. briggsae. C. briggsae shows limited reproduction in larval cultures with an F1 time of 7-11 days at 20 C in a defined medium containing hemin. Addition to the medium of a fraction isolated from soy-peptone yields large populations with an F1 time of 4-5 days. Similar results are obtained in mass culture: without the soy-peptone factor, populations are about 1/6 of those obtained in the presence of the factor. At the present stage of purification, the factor appears to have a molecular weight of less than 1800. Preliminary results indicate that it contains no nucleic acid, little carbohydrate and no specific spectral properties. After hydrolysis, a substantial ninhydrin reaction is obtained. Chromatography of the hydrolysate indicates the presence of 5-6 amino acids. In short, the material appears to consist of a peptide.
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[
1969]
In order to study properly the nutrition and culture of nematodes, it is desirable to establish the organisms in axenic culture. Only in this way can the metabolic abilities of the nematodes be separated from those of coexisting and interacting organisms. One may settle for a mono-axenic culture, but the best way to attain this is to obtain axenic nematodes and then add the second organism or tissue, for example, alfalfa callus tissue for plant parasitic nematodes (Krusberg, 1961). This chapter will devote itself, in the main, to recent work on the culture and nutrition of nematodes, free-living and parasitic, and will refer only in passing to work already thoroughly reviewed (Dougherty et al., 1959; Nicholas, et al., 1959; Dougherty, 1960).
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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.