With a modified color-translating ultraviolet microscope, the distribution of material showing an absorption maximum at 265 mµ was studied in samples from whole cultures of Entamoeba invadens at intervals during growth and from cysts allowed to mature under controlled conditions. Absorption by the cytoplasm in general gradually increased as trophozoites approached the period of maximum encystment. In late trophozoites and precystic forms, the absorbing material was concentrated into small bodies which coalesced to form large crystalloids of very high specific absorption. Maximum crystallization occurred in early cysts, where cytochemical tests have shown the large crystalloids to be ribonucleoprotein. Electron micrographs show that the crystalloids are composed of particles 200 to 300 A in diameter. During cyst maturation the amount of absorbing material per cyst is not visibly reduced, but the large bodies fragment into smaller units until finally there is only a very high diffuse absorption over the entire cyst. From these and other results the hypothesis is advanced that the large crystalloids ("chromatoid bodies") are a manifestation of a special parasite-host adaptive mechanism; ribonucleoprotein is synthesized under favorable conditions, crystallized in the resistant cyst stage, and dispersed in the newly excysted amebae thereby enabling them to establish themselves in a new host by a period of quick growth.
Skip Nav Destination
Article navigation
1 March 1964
Article|
March 01 1964
LOCALIZATION OF CYTOPLASMIC NUCLEIC ACID DURING GROWTH AND ENCYSTMENT OF ENTAMOEBA INVADENS
Douglas Cameron Barker,
Douglas Cameron Barker
From the Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois.
Search for other works by this author on:
George Svihla
George Svihla
From the Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois.
Search for other works by this author on:
Douglas Cameron Barker
From the Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois.
George Svihla
From the Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois.
Dr. Barker's present address is the Department of Zoology, University of Edinburgh, Edinburgh, Scotland
Received:
May 22 1963
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1964 by The Rockefeller Institute Press
1964
J Cell Biol (1964) 20 (3): 389–398.
Article history
Received:
May 22 1963
Citation
Douglas Cameron Barker, George Svihla; LOCALIZATION OF CYTOPLASMIC NUCLEIC ACID DURING GROWTH AND ENCYSTMENT OF ENTAMOEBA INVADENS . J Cell Biol 1 March 1964; 20 (3): 389–398. doi: https://doi.org/10.1083/jcb.20.3.389
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionEmail alerts
Advertisement
Advertisement