Abstract
Differentiation into dormant cysts and vegetative trophozoites is an inherent character intimately associated with the life cycle and infectivity of pathogenic amoebae. In the case of human intestinal amoebiasis encystation and excystation are of immediate relevance to the process of transmission of the disease from healthy carriers to susceptible individuals. Using a pathogenic free living amoebaAcanthamoeba culbertsoni as a model, considerable progress has been achieved in understanding the mechanism and control of the process of differentiation. The turnover of the regulatory molecule cyclic 3: ’5′ adenosine monophosphate is responsible for triggering the process of encystation. Amoebae bind effector molecules such as biogenic amines to a membrane localized receptor which itself resembles the β-adrenergic receptor of mammalian organisms. The activation of adenylate cyclase or inhibition of cyclic AMP phosphodiesterase maintain the dynamic intracellular cyclic AMP. The cytosol fraction of amoebae has a cyclic AMP binding protein. During encystation, enzymes needed for synthesis of cellulose and glycoproteins are induced. Control is exercised at transcriptional level and the process is subject to catabolic repression.
Excystation of mature amoebic cysts is mediated by glutamic acid and certain other amino acids by an as yet unelucidated mechanism. During excystation there is dormancy break, induction of deploymerizing enzymesviz. two proteases, a cellulase and a chitinase. The empty cysts or cyst walls are digested by these enzymes and their break down products are used for cellular growth. By invoking a flip-flop mechanism of repression and derepression some plausible explanation can be offered for the cascade of biochemical events that sets in when amoeba is ‘turned on’ to encystation or excystation.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Achar, S. B. and Weissman, R. A. (1980)Biochim. Biophys. Acta,629, 225.
Balamuth, W. (1951)J. Infect. Dis.,88, 230.
Balamuth, W. and Weiboldt, M. L. (1951)Am. J. Trop. Med.,31, 192.
Band, R. N. (1963)J. Protozool.,19, 101.
Bhagwandeen, S. B., Carter, R. F., Naik, K. G. and Levity, D. (1975):J. Clin. Pathol.,63, 483.
Bowers and Korn (1969)J. Cell Biol.,41; 786.
Batt, C. G. (1966)N. Engl. J. Med.,274, 1473.
Carter, R. (1968)J. Pathol. Bacteriol.,96, 1.
Carter, R. F., Cullity, G. J., Ojeda, V. J., Silberstein, P., Willaert, R. (1981)Pathology,13, 51.
Casemere, D. P. (1969)J. Clin. Pathol.,22, 254.
Carva, L. and Novak, K. (1968)Science,160, 92.
Chang, R. S., Geyer, R. P. and Andrus, S. B. (1962).J. Exp. Med. 115, 405.
Chambers, J. A. and Thompson, J. E. (1972)Exp. Cell. Res.,73, 415.
Culbertson, C. G. (1961)Am. J. Clin. Pathol.,35, 195.
Culbertson, C. G., Emsminger, P. W. and Oerton, W. M. (1966)Am. J. Clin. Pathol.,46, 305.
Diamond, L. S. (1968a)J. Parasitol.,54, 715.
Diamond, L. S. (1968b)J. Parasitol.,54, 1047.
Dobell, G. and Neal, R. A. (1952)Parasitology,42, 16
Duma, R. (1972)Cut. Rev. Clin. Lab. Sci.,3, 163.
Duma, R. (1980)Trends in Neuro Sciences,3, 78.
Eldridge, A. and Tobin, J. (1967)Br. Med. J., 1, 29.
Freedman, L. (1958)South Afr. Med. J.,32, 797.
Fowler, M. and Carter, R. F. (1965)Br. Med. J.,2, 740.
Griffiths, R. J. and Hughes, D. E. (1968)J. Protozoal, 15, 673.
Griffin, J. L. (1978) inParasitic Protozoa (ed. J. P. Krejer) (New York: Acad Press) p. 507.
Grunnet, M. L., Cannon, G. H. and Kushner, J. P. (1981)Neurology, 31, 174.
Jager, B. and Stamn, W. (1972)Lancet, 2, 1343.
Jahnes, W. G., Fullmer, H. M. and Li, C. P. (1957)Proc. Soc. Exp. Biol. Med.,96, 487.
Jonckheere, J. F. de (1981)J. Protozool.,28, 56.
Kaushal, D. C. (1976)Chemical studies on the excystment of amoeba, Ph.D. Thesis, University of Kanpur, Kanpur.
Kaushal, D C and Shukla, O. P. (1975)Indian J. Exp. Biol.,13, 242.
Kaushal, D C and Shukla, O. P. (1976)Indian J. Exp. Biol.,14, 498.
Kaushal, D. C. and Shukla, O. P. (1977a)Indian J. Exp. Biol. 15, 542.
Kaushal, D. C. and Shukla, O. P. (1977b)J. Gen. Microbiol.,98, 117.
Kaushal, D. C. and Shukla, O. P. (1978a)Indian J. Exp. Biol., 16,1104.
Kaushal, D. C. and Shukla, O. P, (1978b)Indian J. Exp. Biol.,16, 1102.
Kaushal, D. C. and Shukla, O. P. (1978c)Indian J. Parasitol.,2, 133.
Kaushal, D. C., Verma, A. K. and Raizada, M. K. (1976)Curr. Sci. 45, 181.
Kenny, M. (1971)Health Lab. Sci.,8, 5.
Krishna Murti, C. R. (1971)Cur. Sci. 40, 589.
Krishna Murti, C. R. (1973)Biochem. Soc. Trans.,1, 1152.
Krishna Murti, C. R. (1975)Indian J. Med. Res.,63, 757.
Matter, F. A. and Byers, T. J. (1971)J. Cell Biol.,49, 507.
Me Connochie E. W. (1969)Parasitology, 59, 41.
Mitra, S. (1975)Biochemical studies on Entamoeba histolytica in relation to encystation, Ph.D. Thesis, University of Nagpur, Nagpur.
Mitra, S. and Krishna Murti, C. R. (1978)Proc. Indian Acad. Sci.,B87, 9.
Moore, A. E. and Hlinka, J. (1968)J. Natl. Cancer Inst.,40, 569.
Nagington, J., Watson, P. G., Play Fair, T. J., Me Gill, J., Jones, B. R. and McSteel, A. D. (1974)Lancet, 2, 1537.
Neal, R. A. (1960)Parasitology,50, 531.
Nef, R. J. (1957)J. Protozool.,4, 176
Nef, R. J. and Neff, R. H. (1969)Symp. Soc. Exp. Biol.,23, 51.
Neff, R. J., Ray, S. A., Benton, W. F. and Wilborn, M. (1964) inMethods in Cell Physiology, (ed. D. M. Prescott), (London and New York: Acad. Press) vol. 1, p. 55.
Peloux, Y., Nicolas, A., Reyron, A. and Beurlet, J. (1974)Pathol. Biol.,22, 587.
Raizada, M. K. (1972)Chemical studies on the encystment of amoeba, Ph.D. Thesis, University of Kanpur, Kanpur.
Raizada, M. K. and Krishna Murti, C. R. (1971a).J. Protozool,18, 115.
Raizada, M. K. and Krishna Murti, C. R. (1971b)Symp. Cellular Growth and Differentiation, BARC, Bombay, 1971, p. 426.
Raizada, M. K. and Krishna Murti, C. R. (1972a)J. Cell Biol. 52, 743.
Raizada, M. K. and Krishna Murti, C. R. (1972b)J. Protozool.,19, 691.
Raizada, M. K., Saxena, K. C. and Krishna Murti, C. R. (1972)J. Protozool, 19, 98.
Raizada, M. K. and Krishna Murti, C. R. (1973)Cur. Sci.,42, 202.
Rivera, F., Galvan, M., Robles, E., Leal, P., Gonzates, L. and Lacy, A. M. (1981)J. Protozool.,28, 54.
Robison, G. A., Butcher, R. W. and Sutherland, E. W. (1971)Cyclic AMP (New York: Acad. Press) p. 84.
Robert, V. B. and Rorke, L. B. (1973)Ann. Int. Med.,79, 174.
Rudick, V. L. and Weisman, R. A. (1973)Nature (London),244, 220.
Singh, B. N. (1965) inPathogenic and Non-Pathogenic Amoebae (London and Basingotoke: The Macmillan Press Ltd).
Singh, B. N. and Das, S. R. (1970)Philos. Trans. R. Soc. London, Ser. B.,236, 405.
Srivastava, D. K. (1982) Ph.D. Thesis, University of Kanpur, Kanpur.
Srivastava, D. K. and Shukla, O. P. (1982)Indian J. Parasitol.,6, 211.
Srivastava, D. K. and Shukfa, O. P. (1983a)Indian J. Exp. Biol.,21, 440.
Srivastava, D. K. and Shukla, O. P. (1983b)Indian J. Exp. Biol.,21, 444.
Stevens, A. R. and Pachler, P. F. (1973)J. Cell Biol.,57, 525.
Sussman, M. (1965)Ann. Rev. Microbiol.,19, 59.
Trager, W. (1963)J. Protozool.,14, 114.
Verma, A. K. (1975)Chemical studies on the differentiation of free living amoeba, Ph.D. Thesis, University of Kanpur, Kanpur, India.
Verma, A. K. and Krishna Murti, C. R. (1975)Biochem. Pharmacol.,24, 1133.
Verma, A. K., Krishna Murti, C. R. (1976a)Indian J. Biochem. Biophys.,13, 247.
Verma, A. K. and Krishna Murti, C. R. (1976b)Indian J. Biochem. Biopkys.,13, 75.
Verma, A. K., Raizada, M. K., Shukla, O. P. and Krishna Murti, C. R. (1974)J. Gen. Microbiol.,80, 307.
Verma, A. K. and Raizada, M. K. (1975)Cell. Differ., 4, 167.
Visveswara, G. S. and Balamuth, W. (1975)J. Protozool.,22, 245.
Visweswara, G. S., Jones, D. and Robinson, N. (1975)J. Trop. Med. Hyg.,24, 784.
WHO ({dy1969})Amoebiasis. Tech. Rep. Series No. 421, World Health Organization, Geneva.
Willaret; R, Stevens, A. R. and Tyndall. R. I. (1978)J. Protozool.,25, 1.
Willmer, E. N. (1963)Symp. Soc. Exp. Biol.,17, 215.
Wright, B. E. (1966)Science,153, 830.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Krishna Murti, C.R., Shukla, O.P. Differentiation of pathogenic amoebae: encystation and excystation ofAcanthamoeba culbertsoni — A model. J Biosci 6, 475–489 (1984). https://doi.org/10.1007/BF02703900
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02703900