Determination of net flux of 14 amino acids inTetrahymena pyriformis
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Influx of14C-labeled aspartate, leucine and glycine intoT. pyriformis occurs from substrate concentrations as low as 1 μM. The relation between concentration and the rate of influx of14C-aspartate is adequately described by the Michaelis-Menten equation, suggesting a carrier-mediated pathway. The influx of14C-labeled leucine and glycine requires an additional term for diffusional exchange, or a second carrier-mediated system.
Fluorometric determination of changes in primary amines in the medium showed a steady increase with time, regardless of the amino acid substrate supplied in the medium, provided the ambient concentration is 25 μM or less. At an ambient amino acid concentration of 70 μM, net entry of primary amines was observed.
Changes in the ambient level of 14 amino acids supplied at initial levels of 0.5 μM and 5.0 μM are studied using high pressure liquid chromatography. There was a net increase in total amino acids in the medium at the lower substrate level (7.0 μM total) and a net decrease at the higher level (70 μM). Observance of a net increase or decrease in the medium of specific amino acids depends on the level supplied initially and the particular substrate.
We conclude that carrier-mediated influx of labeled substrate may be accompanied by a net entry or net loss of that substrate. A general model of amino acid transport is provided. In addition, our findings suggest that influx of free amino acids, intoT. pyriformis from low environmental concentrations plays only a minor role, if any, in providing nutrients.
KeywordsFree Amino Acid High Pressure Liquid Chromatography Primary Amine Amino Acid Transport Amino Acid Concentration
High Pressure Liquid Chromatography
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- Aomine M (1980) The amino acid absorption and transport in protozoa. Comp Biochem Physiol 68A:531–540Google Scholar
- Blum JJ (1980) Effect of chlorpromazine on active transport of amino acids inTetrahymena. J Protozool 27 (4):498–502Google Scholar
- Christensen HN, deCespedes C, Handlogten ME, Ronquist G (1973) Energization of amino acid transport, studied for the Ehrlich ascites tumor cell. Biochim Biophys Acta 300:487–522Google Scholar
- Gardner WS, Lee FG (1975) The role of amino acids in the nitrogen cycle of Lake Mendota. Limnol Oceanogr 20:379–388Google Scholar
- Hamburger K, Zeuthen E (1957) Synchronous divisions inTetrahymena pyriformis in an inorganic medium. Exp Cell Res 13:443–453Google Scholar
- Heinz A, Jackson JW, Richey BE, Sacks G, Schafer JA (1981) Amino acid active transport and stimulation by substrates in the absence of a Na+ electrochemical potential gradient. J Membr Biol 62:149–160Google Scholar
- Hill DL (1972) The Biochemistry and Physiology ofTetrahymena. Academic Press, New YorkGoogle Scholar
- Hoffmann EK, Kramhoft B (1969) A relationship between amino acid and sodium transport inTetrahymena pyriformis. Exp Cell Res 56:265–268Google Scholar
- Hoffman EK, Rasmussen L (1972) Phenylalanine and methionine transport inTetrahymena pyriformis: Characteristics of a concentrating, inducible transport system. Biochim Biophys Acta 266:206–216Google Scholar
- Jones BN, Paabo S, Stein S (1981) Amino acid analysis and enzymatic sequence determination of peptides by an improved o-phthaldialdehyde precolumn labeling procedure. J Liq Chrom 4:564–586Google Scholar
- Jørgensen BC (1976) August Pütter, August Krogh, and modern ideas of the use of dissolved organic matter in aquatic environments. Biol Rev 51:291–328Google Scholar
- Kaneshiro ES, Beischel LS, Merkel LS, Rhoads DE (1979) The fatty acid composition ofParamecium aurelia cells and cilia. J Protozool 26:147–158Google Scholar
- Kidder GW, Dewey UC: The biochemistry of ciliates in pure culture. In: Lwoff A (ed) Biochemistry and physiology of protozoa, vol 1. Academic Press, New York pp 323–400Google Scholar
- Lindroth P, Mopper K (1979) High performance liquid chromatographic determination of subpicomole amounts of amino acids by precolumn fluorescence derivatization with o-phthaldialdehyde. Anal Chem 51:1667–1674Google Scholar
- Ling KY (1977) A study ofl-phenylalanine transport inTetrahymena thermophila. Ph.D. Dissertation, University of California, Santa BarbaraGoogle Scholar
- Neame KD, Richards TG (1972) Elementary kinetics of membrane carrier transport. John Wiley and Sons, New YorkGoogle Scholar
- Pappas PW, Uglem GL, Read CP (1974) Anion and cation requirements for glucose and methionine accumulation byHymenolepis diminuta (Cestoda). Biol Bull 146:56–66Google Scholar
- Rasmussen L (1976) Nutrient uptake inTetrahymena. Carlsberg Res Commun 41:145–167Google Scholar
- Rasmussen L, Orias E (1975)Petrahymena: growth without phagocytosis. Science 190:464–465Google Scholar
- Rasmussen L, Hoffmann EK, Jorgensen CB (1978) Na+-independent uptake of nutrients inTetrahymena. J Comp Physiol 125:97–99Google Scholar
- Reynolds H (1970) Effect of type of carbohydrate on amino acid accumulation and utilization byTetrahymena. J Bacteriol 104:719–725Google Scholar
- Schmidt-Nielsen K (1979) Animal Physiology: Adaptation and Environment. Cambridge University Press, Cambridge, p 163Google Scholar
- Siebers D (1979) Transintegumentary uptake of dissolved amino acids in the sea starAsterias rubens: a reassessment of its nutritional role with special reference to the significance of heterotropic bacteria. Mar Ecol Prog Ser 1:169–177Google Scholar
- Stephens GC, Kerr NS (1962) Uptake of phenylalanine byTetrahymena pyriformis. Nature 194:1094–1095Google Scholar
- Stoner LC, Dunhan PB (1970) Regulation of cellular osmolarity and volume inTetrahymena. J Exp Biol 53:391–399Google Scholar
- Thompson GA Jr, Nozawa Y (1977)Tetrahymena: a system for studying dynamic membrane alterations within the eukaryotic cell. Biochim Biophys Acta 472:55–92Google Scholar
- Thompson GA Jr, Bambery RJ, Nozawa Y (1971) Further studies of the lipid composition and biochemical properties ofTetrahymena pyriformis membrane systems. Biochemistry 10:4441–4447Google Scholar
- Thompson GA Jr, Bambery RJ, Nozawa Y (1972) Environmentally produced alterations in the tetrahymenol: phospholipid ratio inTetrahymena pyriformis membranes. Biochim Biophys Acta 260:630–638Google Scholar
- Wangersky PJ (1978) Production of dissolved organic matter. In: O. Kinne (ed) Marine ecology, vol IV Dynamics. Wiley, Chichester, pp 115–220Google Scholar
- Wheatley DN, Walker E (1980) Comparison of amino acid uptake and incorporation inTetrahymena pyriformis and HeLa cells. J Comp Physiol 140:267–274Google Scholar
- Wright SH, Stephens GC (1977) Characteristics of influx and net flux of amino acids inMytilus californianus. Biol Bull 152:295–310Google Scholar