Increase in Size of Entamoeba Hartmanni Trophozoites Cultured on an Enriched Medium

Ahmad Hajian Institute of Parastology and Malariology, Teheran University, Department of Zoology, University of California, Los Angeles, Iran

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Gordon H. Ball Institute of Parastology and Malariology, Teheran University, Department of Zoology, University of California, Los Angeles, Iran

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Summary

Trophozoites of Entamoeba hartmanni increased significantly in size when they were cultured on an enriched medium. This size increase was not associated with a greater number of binucleate amebae. The greater mean size of E. hartmanni on the enriched medium resulted in a considerable overlap in measurements between culture forms of E. hartmanni and E. histolytica. Since the size increase in E. hartmanni occurred on the first transfer to the enriched medium and continued as long as the amebae were subcultured on it, size is a relatively unstable character in this form and depends to a very great extent upon nutritive conditions. Since E. histolytica and E. hartmanni cannot be separated consistently on the basis of morphological characters or size, it is suggested that a decision on the validity of E. hartmanni as a species distinct from E. histolytica be held in abeyance.

Author Notes

Post-doctoral Research Fellow, U. S. Public Health Service. Grant No. FFG-291.

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