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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Rangachari, K. Articles by Gratzer, W. B. Search for Related Content PubMed PubMed Citation Articles by Rangachari, K. Articles by Gratzer, W. B. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Cytoplasmic factor required for entry of malaria parasites into RBCs K Rangachari, AR Dluzewski, RJ Wilson and WB Gratzer Resealed ghosts of human RBCs, containing diluted cytosol, are susceptible to invasion by Plasmodium falciparum. If ATP is present, a dilution of up to about 30-fold, corresponding to an intracellular hemoglobin concentration of approximately 10 mg/mL, can be tolerated without total loss of susceptibility to invasion. Up to a dilution of about one-half this, the parasites also develop normally. When the cytosol is diluted by more than the critical amount, invasion of the resulting resealed ghosts falls off abruptly. If the diluent buffer is replaced by extraneous concentrated hemolysate, an indefinite dilution is possible without loss of invasion. There is thus an intracellular constituent, which must be present at a concentration above some critical level if the parasite is to enter the cell. The factor in question is not dialyzable. It is largely inactivated when the hemolysate is kept for approximately 1 day in the cold or for approximately 20 minutes at 45 degrees C. The inability of a heat- treated hemolysate to support invasion is not due to the generation of inhibitory products, because such a solution can be used as a diluent of a fresh hemolysate without inhibition of invasion. When the inactivated hemolysate is present as a major component, however, the parasites fail to develop to the trophozoite stage. The invasion-linked factor remains in the strongly adsorbed nonheme fraction when a batchwise separation from hemoglobin on an anion exchanger is made and is thus probably acidic in character; the adsorbed fraction, recovered from the ion-exchanger, substantially restores capacity for invasion when sealed into ghosts. Its activity is destroyed by treatment with trypsin. The adsorbed fraction contains many proteins. When fractionated on a gel filtration column by fast liquid chromatography, active material eluted at a volume corresponding to a mol wt for a globular protein in the region of 10,000. A component of apparent subunit mol wt of 13,000 was observed in sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) of this eluate fraction. Volume 70, Issue 1, pp. 77-82, 07/01/1987 Copyright © 1987 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: S. Frankland, A. Adisa, P. Horrocks, T. F. Taraschi, T. Schneider, S. R. Elliott, S. J. Rogerson, E. Knuepfer, A. F. Cowman, C. I. Newbold, et al. Delivery of the Malaria Virulence Protein PfEMP1 to the Erythrocyte Surface Requires Cholesterol-Rich Domains Eukaryot. Cell, May 1, 2006; 5(5): 849 - 860. [Abstract] [Full Text] [PDF]

	Copyright © 1987 by American Society of Hematology         Online ISSN: 1528-0020